WorldWideScience

Sample records for bonding template light-induced

  1. Templation in Noncovalent Synthesis of Hydrogen-Bonded Rosettes

    NARCIS (Netherlands)

    Crego-Calama, Mercedes; Reinhoudt, David N.; Cate, ten Matthijs G.J.; Schalley, Christoph A.; Vögtle, Fritz; Dötz, Karl Heinz

    2005-01-01

    In this chapter, hydrogen-bonded assemblies based on the rosette motif are used to describe some examples of templation in noncovalent synthesis. After a brief description of the synthesis and characterization of these assemblies, the guest-templated selection and amplification of the strongest bind

  2. Probing Electron-Induced Bond Cleavage at the Single-Molecule Level Using DNA Origami Templates

    DEFF Research Database (Denmark)

    Keller, Adrian Clemens; Bald, Ilko; Rotaru, Alexandru;

    2012-01-01

    specifically designed oligonucleotide targets that are attached to DNA origami templates. In this way, we use a highly selective approach to compare the efficiency of the electron-induced dissociation of a single disulfide bond with the more complex cleavage of the DNA backbone within a TT dinucleotide...

  3. Hydrogen bond templated 1:1 macrocyclization through an olefin metathesis/hydrogenation sequence.

    Science.gov (United States)

    Trita, Andrada Stefania; Roisnel, Thierry; Mongin, Florence; Chevallier, Floris

    2013-07-19

    The construction of pyridine-containing macrocyclic architectures using a nonmetallic template is described. 4,6-Dichlororesorcinol was used as an exotemplate to self-organize two aza-heterocyclic units by OH···N hydrogen bonds. Subsequent sequential double olefin metathesis/hydrogenation reactions employing a single ruthenium-alkylidene precatalyst open access to macrocyclic molecules.

  4. CONCERTED H-BONDING TEMPLATE SYNTHESIS OF AN ORDERED LADDER POLYSILSESQUIOXANE

    Institute of Scientific and Technical Information of China (English)

    Kui-lin Deng; Tao-yi Zhang; Xiao-jing Zhang; Ai-qin Zhang; Ping Xie; Rong-ben Zhang

    2006-01-01

    A novel soluble regular ladder poly(benzoyl-3-aminopropyl) silsesquioxane (LPBAS) was facilely prepared under effective assistance of concerted H-bonding self-assembly of amido groups of side chains and silanol groups, respectively, of a new template monomer [1,3-bis(benzoyl-3-aminopropyl)-1,1,3,3-tetraethoxydisiloxane] (M). The ordered ladder structure of LPBAS is manifested in: (1) the presence of two Bragg peaks representing the ladder width (d) and ladder thickness (t) in X-ray diffraction (XRD) pattern; (2) narrow base-line width (w = 6) of resonance absorption for -CH2SiO3/2 moiety in 29Si-NMR and (3) high glass transition temperature Tg = 112℃ in differential scanning calorimetry (DSC) analysis.

  5. Fabrication of extremely thermal-stable GaN template on Mo substrate using double bonding and step annealing process

    Science.gov (United States)

    Qing, Wang; Yang, Liu; Yongjian, Sun; Yuzhen, Tong; Guoyi, Zhang

    2016-08-01

    A new layer transfer technique which comprised double bonding and a step annealing process was utilized to transfer the GaN epilayer from a sapphire substrate to a Mo substrate. Combined with the application of the thermal-stable bonding medium, the resulting two-inch-diameter GaN template showed extremely good stability under high temperature and low stress state. Moreover, no cracks and winkles were observed. The transferred GaN template was suitable for homogeneous epitaxial, thus could be used for the direct fabrication of vertical LED chips as well as power electron devices. It has been confirmed that the double bonding and step annealing technique together with the thermal-stable bonding layer could significantly improve the bonding strength and stress relief, finally enhancing the thermal stability of the transferred GaN template. Project supported by the Guangdong Innovative Research Team Program (No. 2009010044), the China Postdoctoral Science Foundation (No. 2014M562233), the National Natural Science Foundation of Guangdong, China (No. 2015A030312011), and the Opened Fund of the State Key Laboratory on Integrated Optoelectronics (No. IOSKL2014KF17).

  6. ENDOR Spectroscopy Reveals A Light Induced Movement of the H-Bond from Ser-L223 Upon Forming the Semiquinone (QB−•) in Reaction Centers from Rhodobacter sphaeroides

    Science.gov (United States)

    Paddock, M. L.; Flores, M.; Isaacson, R.; Chang, C.; Abresch, E. C.; Okamura, M.Y.

    2008-01-01

    Proton ENDOR spectroscopy was used to monitor local conformational changes in bacterial reaction centers (RC) associated with the electron transfer reaction DQB → D+•QB−• using mutant RCs capable of photo-reducing QB at cryogenic temperatures. The charge separated state D+•QB−• was studied in mutant RCs formed by either (i) illuminating at low temperature (77K) a sample frozen in the dark (ground state protein conformation) or (ii) illuminating at room temperature prior to and during the freezing (charge separated state protein conformation). The charge recombination rates from the two states differed greatly (>106 fold) as shown previously, indicating a structural change (Paddock et al (2006) Biochemistry 45, 14032 - 14042). ENDOR spectra of QB−• from both samples (35 GHz, 77K) showed three nearly identical sets of hyperfine couplings due to exchangeable protons that were similar to those for QB−• in native RCs indicating that in all RCs, QB−• was located at the proximal position near the metal site. In contrast, one set of H-bond couplings was observed only in the sample frozen under illumination in which the protein can relax prior to freezing. This H-bond was assigned to an interaction between the Ser-L223 hydroxyl and QB−• based on its absence in Ser L223 → Ala mutant RCs. The Ser-L223 hydroxyl H-bond was also observed in the native RCs frozen under illumination. Thus, part of the protein relaxation in response to light induced charge separation involves the formation of an H-bond between the OH group of Ser-L223 and the anionic semiquinone QB−•. This proton movement serves to stabilize the charge separated state and facilitate proton transfer to reduced QB. PMID:17590017

  7. Template-Directed meta-Selective Olefination of Aryl C–H Bonds

    OpenAIRE

    2015-01-01

    Authors: Jinquan Yu ### Abstract The most common bond in many organic compounds is the C–H bond. Hence, it is a great challenge to selectively cleave a particular C–H bond in the presence of multiple ones. One of most widely used approach to this problem is the use of -chelating directing groups (1). However, the insertion of the transition metal is strictly restricted to the ortho-C–H bond through a six- or seven-membered cyclic pre-transition state (TS). Although many strategies ha...

  8. H-Bonding Self-assembled Template-directed Synthesis of a Reactive Amide-bridged Ladder Polyvinylsiloxane

    Institute of Scientific and Technical Information of China (English)

    You Zhi WAN; Ying Hua LIU; Ping XIE; Rong Ben ZHANG

    2006-01-01

    A novel, reactive amide-bridged ladder polyvinylsiloxane (abbr. LP) with Mn = 2.4×104was synthesized for the first time by means of aryl amide H-bonding self-assembled template.The regularity of LP was characterized by the XRD, 29Si NMR and DSC methods. XRD analysis demonstrated the ladder width w = 9.09 A and the ladder thickness t = 3.89 A, respectively, which are approximately consistent with the molecular simulation-calculated ones: w'= 10.60 A and t'=3.06 A. 29Si NMR displayed a resonance peak with small half peak width, △1/2 ~ 4 ppm, for the moiety [=Si(Vi)O2/2-]n of LP. Besides, as a collateral evidence, DSC measurement revealed a high glass transition temperature Tg = 225℃, suggesting high stiffness of the ladder main chain of LP.

  9. Visible-Light-Induced Click Chemistry.

    Science.gov (United States)

    Mueller, Jan O; Schmidt, Friedrich G; Blinco, James P; Barner-Kowollik, Christopher

    2015-08-24

    A rapid and catalyst-free cycloaddition system for visible-light-induced click chemistry is reported. A readily accessible photoreactive 2H-azirine moiety was designed to absorb light at wavelengths above 400 nm. Irradiation with low-energy light sources thus enables efficient small-molecule synthesis with a diverse range of multiple-bond-containing compounds. Moreover, in order to demonstrate the efficiency of the current approach, quantitative ligation of the photoactivatable chromophore with functional polymeric substrates was performed and full conversion with irradiation times of only 1 min at ambient conditions was achieved. The current report thus presents a highly efficient method for applications involving selective cycloaddition to electron-deficient multiple-bond-containing materials.

  10. H-BONDING SELF-ASSEMBLED TEMPLATE-CONTROLLED SYNTHESIS OF A NOVEL SOLUBLE AND REACTIVE AMIDE-BRIDGED LADDERLIKE POLYHYDROSILOXANE

    Institute of Scientific and Technical Information of China (English)

    Guan-qun Zhong; Qing-hua Duan; Kui-lin Deng; Ai-qin Zhang; Ping Xie; Hai-liang Zhang; Rong-ben Zhang

    2006-01-01

    A novel soluble and reactive amide-bridged ladderlike polyhydrosiloxane (ALPHS) was first synthesized by an amido H-bonding self-assembled template. ALPHS with molecular weight M-n = 18300 has very highly ordered ladderlike structure, which was confirmed by a sharp resonance absorption peak of [-Si(H)O2/2 ] moiety with the half peak width A1/2 < 0.5 in 29Si-NMR spectrum. Presence of the reactive Si-H groups gives ALPHS an opportunity to further derive a variety of functional polymers by versatile Si-H reactions such as hydrosilylation, condensation, and so on.

  11. Analysis of IR transmission spectra and hypothesis of bond-centered H diffusion in a-Si: H thin films during light-induced thermal annealing%氢化非晶硅薄膜的红外光谱分析和桥键氢扩散假设

    Institute of Scientific and Technical Information of China (English)

    周怀恩; 朱秀红; 胡跃辉; 马占杰; 张文理; 李瀛; 陈光华

    2005-01-01

    通过红外透射光谱研究了在光诱导退火中退火条件对氢化非晶硅薄膜的结构和光电特性的影响,实验所用样品采用热丝辅助微波电子回旋共振化学气相沉积方法制备.我们用桥键氢扩散模型来解释退火中的不同现象.样品的红外光谱在630和2000cm-1处的吸收系数有所增加,说明了原先的成键氢发生了移动和溢出,我们认为通过光诱导产生载流子的非辐射复合以及桥键氢和深俘获氢原子的交换,产生了大量的桥键氢原子,它们相互结合形成分子氢,氢溢出要优于氢团聚.%The effect of light-induced thermal annealing at low temperature on the structure and electronic properties of hydrogenated amorphous silicon (a-Si : H ) as a function of annealing conditions was studied by FTIR spectra method. The deposition of a-Si: H films was performed by using microwave electron cyclotron resonance (MW ECR) plasma with the assistance of tungsten filament. In this study, the infrared spectroscopy results show the interesting changes under the different annealing condition. The increase in the transmission coefficient at both 630 and 2000cm-1 indicates that bonded hydrogen moved and effused from the amorphous network. The bond-centered (BC) H diffusion model is used to explain the H elimination phenomenon, we argue that the BC H atoms formed by the nonradiative recombination of photo-induced carriers and the exchange between BC H and deeply trapped H produce more and more BC H atoms, the BC H atoms will recombine each other and form molecular hydrogen, the process of H elimination is prior to monohydride clustering and/or bonds switching.

  12. H-bonding template-directed synthesis of a complete m-PDA-bridged ladder polyhydrosiloxane (OLPHS)

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A highly ordered m-phenylenediimino-bridged ladder polyhydrosiloxane (abbr. OLPHS) with Mn = 1.24 × 104 was synthesized stoichiometric hydrolysis and dehydrochlorination condensation reaction between Si-Cl and Si-OH bonds. The complete ladder structure of OLPHS has been confirmed by the following three data. Two characteristic Bragg's peaks representing the ladder width (w = 0.94 nm) and ladder thickness (t = 0.42 nm) were observed in XRD analysis, which are consistent with those calculated by molecular simulation. The very sharp absorption with a small half-peak width (w1/2 = 0.5 ppm) for [(-HN)HSiO2/2]n moiety of OLPHS in 29Si NMR spectrum indicated presence of the complete ladder structure. As collateral evidence, a higher glass transition temperature (Tg = 105 ℃) is also recorded in the DSC measurement, implying the high stiffness of ladder chain of OLPHS.(C) 2007 Rong Ben Zhang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

  13. UV Light Induces Dedoping of Polyaniline

    Directory of Open Access Journals (Sweden)

    Yuki Kaitsuka

    2016-01-01

    Full Text Available UV (Ultra-Violet light-driven change in optical absorption of polyaniline (PANI is reported. Irradiation of UV light to PANI/camphor sulfonic acid prepared by electrochemical polymerization allows dedoping of the PANI. Especially, UV light irradiation in the presence of a radical trap agent effectively reduces (dedoping the PANI. The result in this study is quite simple; however, this may be a first report for light-induced dedoping (color change of a conductive polymer.

  14. Broadband Visible Light Induced NO Formation

    Science.gov (United States)

    Lubart, Rachel; Eichler, Maor; Friedmann, Harry; Savion, N.; Breitbart, Haim; Ankri, Rinat

    2009-06-01

    Nitric oxide formation is a potential mechanism for photobiomodulation because it is synthesized in cells by nitric oxide synthase (NOS), which contains both flavin and heme, and thus absorbs visible light. The purpose of this work was to study broadband visible light induced NO formation in various cells. Cardiac, endothelial, sperm cells and RAW 264.7 macrophages were illuminated with broadband visible light, 40-130 mW/cm2, 2.4-39 J/cm2, and nitric oxide production was quantified by using the Griess reagent. The results showed that visible light illumination increased NO concentration both in sperm and endothelial cells, but not in cardiac cells. Activation of RAW 264.7 macrophages was very small. It thus appears that NO is involved in photobiomodulation, though different light parameters and illumination protocols are needed to induce NO in various cells.

  15. Light-Induced Dielectrophoretic Manipulation of DNA

    Science.gov (United States)

    Hoeb, Marco; Rädler, Joachim O.; Klein, Stefan; Stutzmann, Martin; Brandt, Martin S.

    2007-01-01

    Light-induced dielectrophoretic movement of polystyrene beads and λ-DNA is studied using thin films of amorphous hydrogenated silicon as local photoaddressable electrodes with a diameter of 4 μm. Positive (high-field seeking) dielectrophoretic movement is observed for both types of objects. The absence of strong negative (low-field seeking) dielectrophoresis of DNA at high frequencies is in agreement with the similarity of the dielectric constants of DNA and water, the real part of the dielectric function. The corresponding imaginary part of the dielectric function governed by the conductivity of DNA can be determined from a comparison of the frequency dependence of the dielectrophoretic drift velocity with the Clausius-Mossotti relation. PMID:17483160

  16. Magnetic routing of light-induced waveguides

    Science.gov (United States)

    Izdebskaya, Yana; Shvedov, Vladlen; Assanto, Gaetano; Krolikowski, Wieslaw

    2017-01-01

    Among photofunctional materials that can be employed to control the propagation of light by modifying their properties, soft dielectrics such as nematic liquid crystals (NLCs) stand out for their large all-optical response. Through reorientation, the molecular distribution of NLCs can be modified by the electric field of light, permitting functional operations and supporting self-localized light beams or spatial optical solitons. To date, the generation and routing of such solitons have been limited by the boundary conditions employed to tailor the properties of NLCs in planar cells or capillaries. Here we report on spatial solitons in bulk NLCs with no lateral anchoring, where the application of an external magnetic field effectively controls the direction of propagation and the angular steering of the self-trapped wavepackets. Our results entail a completely new approach to the routing of self-localized beams and light-induced waveguides in three dimensions, without the usual limitations imposed by transverse boundary conditions. PMID:28198374

  17. Dimensionality constraints of light induced rotation

    CERN Document Server

    Oroszi, László; Galajda, Péter; Kelemen, Lóránd; Mathesz, Anna; Vicsek, Tamás; Vizsnyiczai, Gaszton; Ormos, Pál

    2015-01-01

    We have studied the conditions of rotation induced by collimated light carrying no angular momentum. Objects of different shapes and optical properties were examined in the nontrivial case where the rotation axis is perpendicular to the direction of light propagation. This geometry offers important advantages for application as it fundamentally broadens the possible practical arrangements to be realised. We found that collimated light cannot drive permanent rotation of 2D or prism-like 3D objects (i.e. fixed cross-sectional profile along the rotation axis) in the case of fully reflective or fully transparent materials. Based on both geometrical optics simulations and theoretical analysis, we derived a general condition for rotation induced by collimated light carrying no angular momentum valid for any arrangement: Permanent rotation is not possible if the scattering interaction is two-dimensional and lossless. In contrast, light induced rotation can be sustained if partial absorption is present or the object ...

  18. EDITORIAL Light-induced material organization Light-induced material organization

    Science.gov (United States)

    Vainos, Nikos; Rode, Andrei V.

    2010-12-01

    Light-induced material organization extends over a broad area of research, from photon momentum transfer to atoms, molecules and particles, serving the basis for optical trapping, and expands into the laser-induced changes of material properties through photopolymerization, photodarkening, and materials ablation. Relevant phenomena are observed over many orders of magnitude of light intensity, from a few kW cm-2 for the optical trapping of living cells to 1014 W cm-2 encountered in femtosecond laser micromachining and micro-explosion. Relevant interactions reveal a rich palette of novel phenomena in the solid state, from subtle excitations and material organization to phase transformations, non-equilibrium and transient states. The laser-induced material modifications relate to changes in the crystal structure and the molecular bonding, phase transitions in liquid state, ablation and plasma production associated with extreme pressure and temperature conditions towards entirely new states of matter. The underlying physical mechanisms form the foundations for micro-engineering photonic and other functional devices and lead the way to relevant applications. At the same time, they hold the potential for creating non-equilibrium material states and a range of fundamentally new products not available by other means. The fundamental understanding of both materials nature and functional behaviour will ultimately yield novel devices and improved performance in several fields. The far reaching goals of these studies relate to the development of new methods and technologies for micro- and nano-fabrication, not only offering a significant reduction of cost, but also expanding the fabrication capabilities into unexplored areas of biophotonics and nanotechnology. This special issue of Journal of Optics presents some very recent and exciting advances in the field of materials manipulation by laser beams, aiming to underline its current trends. In optical trapping research we

  19. Light induced structural changes of the photoprotein mnemiopsin: Characterization and contribution in photoinactivation.

    Science.gov (United States)

    Pashandi, Zaiddodine; Molakarimi, Maryam; Sajedi, Reza H; Taghdir, Majid; Naderi-Manesh, Hossein

    2016-12-01

    Mnemiopsin, an EF-hand Ca(2+) binding photoprotein isolated from luminous ctenophore Mnemiopsis leidyi, emits blue light from its chromophore, coelenterazine, which is non-covalently bond in its central hydrophobic core. Previous studies have revealed unique biochemical properties for ctenophore photoproteins such as inactivation by light, but only few have focused on photoinactivation process. To understand the nature of photoinactivation process we have investigated the impact of light alone and in the presence of Ca(2+) ion on the structure of this photoprotein. We used UV-Vis, circular dichroism (CD) and fluorescence spectroscopy following Ca(2+) binding assay to analyze the light effects on mnemiopsin conformation in comparison with aequorin at both apo and holo form. Our results showed light induced structural changes which resulted into photoinactivation. These changes include significant modification on secondary structure of mnemiopsin in comparison with aequorin. Our data also revealed that light could influence structure of apo protein regardless of presence of coelenterazine. The comparative studies of Ca(2+) ion binding affinity following light exposure, also showed that light induced structural changes could presumably affect coelenterazine binding or its conformation in binding site in such a way that causes photoinactivation. In conclusion, we have proposed that structural rearrangement of helix 5 and C-terminal motif could be responsible for light induced structural changes.

  20. VUV-light-induced deposited silica films

    Science.gov (United States)

    Buck, Christopher K.; Pedraza, Anthony J.; Benson, Roberto S.; Park, Jae-Won

    1998-05-01

    A novel technique to deposit dielectric films at room temperature is described. The deposition of the silica takes place inside a cylindrical glass chamber where a silent discharge is generated between two electrodes connected to a high voltage, high frequency AC source. The chamber contains two parallel glass tubes where the electrodes are located and is filled with argon or xenon at a pressure of 100 mbar. Under these conditions, it has been shown that high intensity VUV light is generated peaking at 126 nm for argon and at 172 nm for xenon. This VUV radiation seems to produce photoablation of the glass tubes that surround the electrodes. Upon operation of the lamp, polyimide, polypropylene and silicon wafer substrates lying at the bottom of the vessel became coated with silica. The films, identified using X-ray photoelectron spectroscopy (XPS), revealed that the silica is oxygen-deficient with a composition of SiO x where x is between 1.7 and 1.8. The deposition rate on silicon wafers was measured by ellipsometry. When Xe gas is used the deposition rate is much lower than when Ar is used. This result is consistent with a photoablation process since the energy of the photons generated in Ar peaks at 10 eV while those generated in Xe peaks at 7 eV. These energy values should be compared with the O-Si bond strength energy that is 8.3 eV. The morphology and structure of the films were examined by scanning and transmission electron microscopies. Deposition of carbonaceous films occurred when the glass tubes containing the electrodes were coated with carbon.

  1. Hydrogen Bonding-Mediated Microphase Separation during the Formation of Mesoporous Novolac-Type Phenolic Resin Templated by the Triblock Copolymer, PEO-b-PPO-b-PEO

    Directory of Open Access Journals (Sweden)

    Wei-Cheng Chu

    2013-11-01

    Full Text Available After blending the triblock copolymer, poly(ethylene oxide-b-propylene oxide-b-ethylene oxide (PEO-b-PPO-b-PEO with novolac-type phenolic resin, Fourier transform infrared spectroscopy revealed that the ether groups of the PEO block were stronger hydrogen bond acceptors for the OH groups of phenolic resin than were the ether groups of the PPO block. Thermal curing with hexamethylenetetramine as the curing agent resulted in the triblock copolymer being incorporated into the phenolic resin, forming a nanostructure through a mechanism involving reaction-induced microphase separation. Mild pyrolysis conditions led to the removal of the PEO-b-PPO-b-PEO triblock copolymer and formation of mesoporous phenolic resin. This approach provided a variety of composition-dependent nanostructures, including disordered wormlike, body-centered-cubic spherical and disorder micelles. The regular mesoporous novolac-type phenolic resin was formed only at a phenolic content of 40–60 wt %, the result of an intriguing balance of hydrogen bonding interactions among the phenolic resin and the PEO and PPO segments of the triblock copolymer.

  2. Light-Induced Absorption in Nominally Pure Bismuth Silicon Oxide

    Institute of Scientific and Technical Information of China (English)

    李飞飞; 许京军; 孔勇发; 黄辉; 张光寅; 杨春晖; 徐玉恒

    2001-01-01

    Light-induced absorption in the nominally pure bismuth silicon oxide is investigated experimentally and the result shows that it consists of transient and persistent parts. The experimental evidence is analysed based on the model of three groups of trap (donor) centres.

  3. Code Generation with Templates

    CERN Document Server

    Arnoldus, Jeroen; Serebrenik, A

    2012-01-01

    Templates are used to generate all kinds of text, including computer code. The last decade, the use of templates gained a lot of popularity due to the increase of dynamic web applications. Templates are a tool for programmers, and implementations of template engines are most times based on practical experience rather than based on a theoretical background. This book reveals the mathematical background of templates and shows interesting findings for improving the practical use of templates. First, a framework to determine the necessary computational power for the template metalanguage is presen

  4. Light-induced metastable structural changes in hydrogenated amorphous silicon

    Energy Technology Data Exchange (ETDEWEB)

    Fritzsche, H. [Univ. of Chicago, IL (United States)

    1996-09-01

    Light-induced defects (LID) in hydrogenated amorphous silicon (a-Si:H) and its alloys limit the ultimate efficiency of solar panels made with these materials. This paper reviews a variety of attempts to find the origin of and to eliminate the processes that give rise to LIDs. These attempts include novel deposition processes and the reduction of impurities. Material improvements achieved over the past decade are associated more with the material`s microstructure than with eliminating LIDs. We conclude that metastable LIDs are a natural by-product of structural changes which are generally associated with non-radiative electron-hole recombination in amorphous semiconductors.

  5. Light-Induced Charge Separation and Transfer in Bacteriorhodopsin

    Institute of Scientific and Technical Information of China (English)

    HUANG Yu-Hua; LI Qing-Guo; ZHAO You-Yuan; ZHANG Zhong-Bin; OU-YANG Xiao-Ping; GONG Qin-Gan; CHEN Ling-Bing; LI Fu-Ming; LIU Jian; DING Jian-Dong

    2000-01-01

    The photo-voltage signals in bacteriorhodopsin(bR) excited by 1064nm pulse laser are different from those by 532 or 355 nm. It shows that the positive and negative photoelectric signals are produced by the motion of the positive and negative charges, respectively, and more energy is needed for producing the positive charges than the negative. The mechanism of light-induced charge generation and charge transfer in bR was studied and analyzed by measuring the photoelectric signals with different impedance of measuring circuit and different pulse-width of 532 nm laser as pump light.

  6. Light-Induced Switching of Tunable Single-Molecule Junctions

    KAUST Repository

    Sendler, Torsten

    2015-04-16

    A major goal of molecular electronics is the development and implementation of devices such as single-molecular switches. Here, measurements are presented that show the controlled in situ switching of diarylethene molecules from their nonconductive to conductive state in contact to gold nanoelectrodes via controlled light irradiation. Both the conductance and the quantum yield for switching of these molecules are within a range making the molecules suitable for actual devices. The conductance of the molecular junctions in the opened and closed states is characterized and the molecular level E 0, which dominates the current transport in the closed state, and its level broadening Γ are identified. The obtained results show a clear light-induced ring forming isomerization of the single-molecule junctions. Electron withdrawing side-groups lead to a reduction of conductance, but do not influence the efficiency of the switching mechanism. Quantum chemical calculations of the light-induced switching processes correlate these observations with the fundamentally different low-lying electronic states of the opened and closed forms and their comparably small modification by electron-withdrawing substituents. This full characterization of a molecular switch operated in a molecular junction is an important step toward the development of real molecular electronics devices.

  7. Light-induced bird strikes on vessels in Southwest Greenland

    DEFF Research Database (Denmark)

    Merkel, Flemming Ravn; Johansen, Kasper Lambert

    2011-01-01

    Light-induced bird strikes are known to occur when vessels navigate during darkness in icy waters using powerful searchlight. In Southwest Greenland, which is important internationally for wintering seabirds, we collected reports of incidents of bird strikes over 2–3 winters (2006–2009) from navy...... vessels, cargo vessels and trawlers (total n = 19). Forty-one incidents were reported: mainly close to land (birds were reported killed in a single incident. All occurred between 5 p.m. and 6 a.m. and significantly more birds were involved when...... visibility was poor (snow) rather than moderate or good. Among five seabird species reported, the common eider (Somateria mollissima) accounted for 95% of the bird casualties. Based on spatial analyses of data on vessel traffic intensity and common eider density we are able to predict areas with high risk...

  8. Light-induced performance increase of silicon heterojunction solar cells

    KAUST Repository

    Kobayashi, Eiji

    2016-10-11

    Silicon heterojunction solar cells consist of crystalline silicon (c-Si) wafers coated with doped/intrinsic hydrogenated amorphous silicon (a-Si:H) bilayers for passivating-contact formation. Here, we unambiguously demonstrate that carrier injection either due to light soaking or (dark) forward-voltage bias increases the open circuit voltage and fill factor of finished cells, leading to a conversion efficiency gain of up to 0.3% absolute. This phenomenon contrasts markedly with the light-induced degradation known for thin-film a-Si:H solar cells. We associate our performance gain with an increase in surface passivation, which we find is specific to doped a-Si:H/c-Si structures. Our experiments suggest that this improvement originates from a reduced density of recombination-active interface states. To understand the time dependence of the observed phenomena, a kinetic model is presented.

  9. Light-induced structural changes in a monomeric bacteriophytochrome

    Directory of Open Access Journals (Sweden)

    Heikki Takala

    2016-09-01

    Full Text Available Phytochromes sense red light in plants and various microorganism. Light absorption causes structural changes within the protein, which alter its biochemical activity. Bacterial phytochromes are dimeric proteins, but the functional relevance of this arrangement remains unclear. Here, we use time-resolved X-ray scattering to reveal the solution structural change of a monomeric variant of the photosensory core module of the phytochrome from Deinococcus radiodurans. The data reveal two motions, a bend and a twist of the PHY domain with respect to the chromophore-binding domains. Infrared spectroscopy shows the refolding of the PHY tongue. We conclude that a monomer of the phytochrome photosensory core is sufficient to perform the light-induced structural changes. This implies that allosteric cooperation with the other monomer is not needed for structural activation. The dimeric arrangement may instead be intrinsic to the biochemical output domains of bacterial phytochromes.

  10. Functional analysis of chloroplast early light inducible proteins (ELIPs)

    Energy Technology Data Exchange (ETDEWEB)

    Wetzel, Carolyn M

    2005-02-22

    The objectives of this project were to characterize gene expression patterns of early light inducible protein (ELIP) genes in Arabidopsis thaliana and in Lycopersicon esculentum, to identify knock mutants of the 2 ELIP genes in Arabidopsis, and to characterize the effects of the knockouts. Expression in Arabidopsis was studied in response to thylakoid electron transport chain (PETC) capacity, where it was found that there is a signal for expression associated with reduction of the PETC. Expression in response to salt was also studied, with different responses of the two gene copies. Knockout lines for ELIP1 and ELIP2 have been identified and are being characterized. In tomato, it was found that the single-copy ELIP gene is highly expressed in ripening fruit during the chloroplast-to-chromoplast transition. Studies of expression in tomato ripening mutants are ongoing.

  11. Visible-light-induced photocatalysis of 2D-hexagonal mesoporous SiO2-TiO2 deposited with Au nanoparticles.

    Science.gov (United States)

    Kawamura, Go; Okuno, Teruhisa; Muto, Hiroyuki; Matsuda, Atsunori

    2014-03-01

    Au nanoparticles (NPs) are deposited using a couple of methods onto a sol-gel-derived mesoporous SiO2-TiO2 template. A modification of the template with 3-aminopropyltriethoxysilane (APTES) before the deposition of Au leads to the formation of Au nanorods instead of Au nanospheres in the tubular mesopores. The modification also causes a deterioration of visible-light-induced photocatalytic activity. Heat treatment of this sample to remove APTES results in an amelioration of the photocatalytic activity. The detailed mechanism of the deterioration and amelioration of the activity is discussed on the accessibility of the reactant to the sample and the easiness of the charge carrier transfer between TiO2 and Au NPs.

  12. Light-induced self-assembly of active rectification devices.

    Science.gov (United States)

    Stenhammar, Joakim; Wittkowski, Raphael; Marenduzzo, Davide; Cates, Michael E

    2016-04-01

    Self-propelled colloidal objects, such as motile bacteria or synthetic microswimmers, have microscopically irreversible individual dynamics-a feature they share with all living systems. The incoherent behavior of individual swimmers can be harnessed (or "rectified") by microfluidic devices that create systematic motions that are impossible in equilibrium. We present a computational proof-of-concept study showing that such active rectification devices could be created directly from an unstructured "primordial soup" of light-controlled motile particles, solely by using spatially modulated illumination to control their local propulsion speed. Alongside both microscopic irreversibility and speed modulation, our mechanism requires spatial symmetry breaking, such as a chevron light pattern, and strong interactions between particles, such as volume exclusion, which cause a collisional slowdown at high density. Together, we show how these four factors create a novel, many-body rectification mechanism. Our work suggests that standard spatial light modulator technology might allow the programmable, light-induced self-assembly of active rectification devices from an unstructured particle bath.

  13. Light induced DEP for immobilizing and orienting Escherichia coli bacteria

    Science.gov (United States)

    Miccio, Lisa; Marchesano, Valentina; Mugnano, Martina; Grilli, Simonetta; Ferraro, Pietro

    2016-01-01

    Manipulating bacteria and understanding their behavior when interacting with different substrates are of fundamental importance for patterning, detection, and any other topics related to health-care, food-enterprise, etc. Here, we adopt an innovative dielectrophoretic (DEP) approach based on electrode-free DEP for investigating smart but simple strategies for immobilization and orientation of bacteria. Escherichia coli DH5-alpha strain has been selected as subject of the study. The light induced DEP is achieved through ferroelectric iron-doped lithium niobate crystals used as substrates. Due to the photorefractive (PR) property of such material, suitable light patterns allow writing spatial-charges-distribution inside its volume and the resultant electric fields are able to immobilize E. coli on the surface. The experiments showed that, after laser irradiation, about 80% of bacteria is blocked and oriented along a particular direction on the crystals within an area of few square centimeters. The investigation presented here could open the way for detection or patterning applications based on a new driving mechanism. Future perspectives also include the possibility to actively switch by light the DEP forces, through the writing/erasing characteristic of PR fields, to dynamically control biofilm spatial structure and arrangement.

  14. A light-induced shortcut in the planktonic microbial loop

    KAUST Repository

    Ptacnik, Robert

    2016-07-11

    Mixotrophs combine photosynthesis with phagotrophy to cover their demands in energy and essential nutrients. This gives them a competitive advantage under oligotropihc conditions, where nutrients and bacteria concentrations are low. As the advantage for the mixotroph depends on light, the competition between mixo- and heterotrophic bacterivores should be regulated by light. To test this hypothesis, we incubated natural plankton from the ultra-oligotrophic Eastern Mediterranean in a set of mesocosms maintained at 4 light levels spanning a 10-fold light gradient. Picoplankton (heterotrophic bacteria (HB), pico-sized cyanobacteria, and small-sized flagellates) showed the fastest and most marked response to light, with pronounced predator-prey cycles, in the high-light treatments. Albeit cell specific activity of heterotrophic bacteria was constant across the light gradient, bacterial abundances exhibited an inverse relationship with light. This pattern was explained by light-induced top-down control of HB by bacterivorous phototrophic eukaryotes (PE), which was evidenced by a significant inverse relationship between HB net growth rate and PE abundances. Our results show that light mediates the impact of mixotrophic bacterivores. As mixo- and heterotrophs differ in the way they remineralize nutrients, these results have far-reaching implications for how nutrient cycling is affected by light.

  15. A possible mechanism for visible-light-induced skin rejuvenation

    Science.gov (United States)

    Longo, Leonardo; Lubart, Rachel; Friedman, Harry; Lavie, R.

    2004-09-01

    In recent years there has been intensive research in the field of non-ablative skin rejuvenation. This comes as a response to the desire for a simple method of treating rhytids caused by aging, UV exposure and acne scars. In numerous studies intense visible light pulsed systems (20-30J/cm2) are used. The mechanism of action was supposed to be a selective heat induced denaturalization of dermal collagen that leads to subsequent reactive synthesis. In this study we suggest a different mechanism for photorejuvenation based on light induced Reactive Oxygen Species (ROS) formation. We irradiated collagen in-vitro with a broad band of visible light, 400-800 nm, 12-22J/cm2, and used the spin trapping coupled with electron paramagnetic resonance (EPR) spectroscopy to detect ROS. In vivo, we used dose 30 J in average (35 for acnis scars, 25 for wrinkles and redness). Irradiated collagen results in hydroxyl and methyl radicals formation. We propose, as a new concept, that visible light at the intensity used for skin rejuvenation, 20-30J/cm2, produces high amounts of ROS which destroy old collagen fibers encouraging the formation of new ones. On the other hand at inner depths of the skin, where the light intensity is much weaker, low amounts of ROS are formed which are well known to stimulate fibroblast proliferation.

  16. Diagnosis of dental caries using quantitative light-induced fluorescence

    Science.gov (United States)

    Amaechi, Bennett T.; Higham, Susan M.

    2001-10-01

    Current dental diagnostic methods can detect caries but cannot quantify the mineral status of the lesion. Quantitative Light-induced Fluorescence (QLF) measures the percentage fluorescence radiance change of demineralised enamel with respect to surround sound enamel, and related it directly to the amount of mineral lost during demineralisation. Demineralisation of teeth to produce caries-like lesions and the subsequent remineralisation of the lesions were monitored quantitatively and longitudinally with QLF. The influence of factors such as presence of plaque or saliva, lesion staining, lesion magnification, tooth thickness and developmental hypomineralisation, on the reproducibility of QLF imaging and analysis were investigated, Results showed that the integrated fluorescence change (hence the mineral loss) increased linearly with demineralisation time and decreased with increasing remineralisation time. Caries detection was limited by saliva or plaque, but enhanced by staining. QLF could not discriminate between developmental hypomineralisation and caries. Neither the variation in tooth thickness nor lesion magnification within the limit of a sharp image made a significant difference in QLF analysis. It was concluded that QLF could detect and quantitatively monitor the mineral changes in an incipient caries on a longitudinal basis, however detection may be limited by the presence of saliva or plaque or enhanced by staining.

  17. Light-induced atom desorption from glass surfaces characterized by X-ray photoelectron spectroscopy

    Science.gov (United States)

    Kumagai, Ryo; Hatakeyama, Atsushi

    2016-07-01

    We analyzed the surfaces of vitreous silica (quartz) and borosilicate glass (Pyrex) substrates exposed to rubidium (Rb) vapor by X-ray photoelectron spectroscopy (XPS) to understand the surface conditions of alkali metal vapor cells. XPS spectra indicated that Rb atoms adopted different bonding states in quartz and Pyrex. Furthermore, Rb atoms in quartz remained in the near-surface region, while they diffused into the bulk in Pyrex. For these characterized surfaces, we measured light-induced atom desorption (LIAD) of Rb atoms. Clear differences in time evolution, photon energy dependence, and substrate temperature dependence were found; the decay of LIAD by continuous ultraviolet irradiation for quartz was faster than that for Pyrex, a monotonic increase in LIAD with increasing photon energy from 1.8 to 4.3 eV was more prominent for quartz, and LIAD from quartz was more efficient at higher temperatures in the range from 300 to 580 K, while that from Pyrex was almost independent of temperature.

  18. Microsecond light-induced proton transfer to flavin in the blue light sensor plant cryptochrome.

    Science.gov (United States)

    Langenbacher, Thomas; Immeln, Dominik; Dick, Bernhard; Kottke, Tilman

    2009-10-14

    Plant cryptochromes are blue light photoreceptors that regulate key responses in growth and daily rhythm of plants and might be involved in magnetoreception. They show structural homology to the DNA repair enzyme photolyase and bind flavin adenine dinucleotide as chromophore. Blue light absorption initiates the photoreduction from the oxidized dark state of flavin to the flavin neutral radical, which is the signaling state of the sensor. Previous time-resolved studies of the photoreduction process have been limited to observation of the decay of the radical in the millisecond time domain. We monitored faster, light-induced changes in absorption of an algal cryptochrome covering a spectral range of 375-750 nm with a streak camera setup. Electron transfer from tryptophan to flavin is completed before 100 ns under formation of the flavin anion radical. Proton transfer takes place with a time constant of 1.7 micros leading to the flavin neutral radical. Finally, the flavin radical and a tryptophan neutral radical decay with a time constant >200 micros in the millisecond and second time domain. The microsecond proton transfer has not been observed in animal cryptochromes from insects or photolyases. Furthermore, the strict separation in time of electron and proton transfer is novel in the field of flavin-containing photoreceptors. The reaction rate implies that the proton donor is not in hydrogen bonding distance to the flavin N5. Potential candidates for the proton donor and the involvement of the tryptophan triad are discussed.

  19. Evidence for a distinct light-induced calcium-dependent potassium current in Hermissenda crassicornis.

    Science.gov (United States)

    Blackwell, K T

    2000-01-01

    A model of phototransduction is developed as a first step toward a model for investigating the critical interaction of light and turbulence stimuli within the type B photoreceptor of Hermissenda crassicronis. The model includes equations describing phototransduction, release of calcium from intracellular stores, and other calcium regulatory mechanisms, as well as equations describing ligand-gating of a rhabdomeric sodium current. The model is used to determine the sources of calcium in the soma, whether calcium or IP3 is a plausible ligand of the light-induced sodium current, and whether the light-induced potassium current is equivalent to the calcium-dependent potassium current activated by light-induced calcium release. Simulations show that the early light-induced calcium elevation is due to influx through voltage-dependent channels, whereas the later calcium elevation is due to release from intracellular stores. Simulations suggest that the ligand of the fast, light-induced sodium current is IP3 but that there is a smaller, prolonged component of the light-induced sodium current that is activated by calcium. In the model, the calcium-dependent potassium current, located in the soma, is activated only slightly by light-induced calcium elevation, leading to the prediction that a calcium-dependent potassium current, active at resting potential, is located in the rhabdomere and is responsible for the light-induced potassium current.

  20. Light induced oxidative water splitting in photosynthesis: energetics, kinetics and mechanism.

    Science.gov (United States)

    Renger, Gernot

    2011-01-01

    The essential steps of photosynthetic water splitting take place in Photosystem II (PSII) and comprise three different reaction sequences: (i) light induced formation of the radical pair P680(+)Q(A)(-), (ii) P680(+) driven oxidative water splitting into O(2) and four protons, and (iii) two step plastoquinone reduction to plastoquinol by Q(A)(-). This mini-review briefly summarizes our state of knowledge on energetics, kinetics and mechanism of oxidative water splitting. Essential features of the two types of reactions involved are described: (a) P680(+) reduction by the redox active tyrosine Y(z) and (b) sequence of oxidation steps induced by Y(z)(ox) in the water-oxidizing complex (WOC). The rate of the former reaction is limited by the non-adiabatic electron transfer (NET) step and the multi-phase kinetics shown to originate from a sequence of relaxation processes. In marked contrast, the rate of the stepwise oxidation by Y(z)(ox) of the WOC up to the redox level S(3) is not limited by NET but by trigger reactions which probably comprise proton shifts and/or conformational changes. The overall rate of the final reaction sequence leading to formation and release of O(2) is assumed to be limited by the electron transfer step from the S(3) state of WOC to Y(z)(ox) due to involvement of an endergonic redox equilibrium. Currently discussed controversial ideas on possible pathways are briefly outlined. Several crucial points of the mechanism of oxidative water splitting, like O-O bond formation, role of local proton shift(s), details of hydrogen bonding, are still not clarified and remain a challenging topic of future research.

  1. Templating mesoporous zeolites

    DEFF Research Database (Denmark)

    Egeblad, Kresten; Christensen, Christina Hviid; Kustova, Marina

    2008-01-01

    The application of templating methods to produce zeolite materials with hierarchical bi- or trimodal pore size distributions is reviewed with emphasis on mesoporous materials. Hierarchical zeolite materials are categorized into three distinctly different types of materials: hierarchical zeolite...... crystals, nanosized zeolite crystals, and supported zeolite crystals. For the pure zeolite materials in the first two categories, the additional meso- or macroporosity can be classified as being either intracrystalline or intercrystalline, whereas for supported zeolite materials, the additional porosity...... originates almost exclusively from the support material. The methods for introducing mesopores into zeolite materials are discussed and categorized. In general, mesopores can be templated in zeolite materials by use of solid templating, supramolecular templating, or indirect templating...

  2. Manipulating scattering of ultracold atoms with light-induced dissipation

    CERN Document Server

    Lemeshko, Mikhail

    2013-01-01

    Recently it has been shown that pairs of atoms can form metastable bonds due to non-conservative forces induced by dissipation [Lemeshko&Weimer, Nature Comm. 4, 2230 (2013)]. Here we study the dynamics of interaction-induced coherent population trapping - the process responsible for the formation of dissipatively bound molecules. We derive the effective dissipative potentials induced between ultracold atoms by laser light, and study the time evolution of the scattering states. We demonstrate that binding occurs on short timescales of ~10 microseconds, even if the initial kinetic energy of the atoms significantly exceeds the depth of the dissipative potential. Dissipatively-bound molecules with preordained bond lengths and vibrational wavefunctions can be created and detected in current experiments with ultracold atoms.

  3. SiO2/TiO2 Nanocomposite Films on Polystyrene for Light-Induced Cell Detachment Application.

    Science.gov (United States)

    Cheng, Zhiguo; Cheng, Kui; Weng, Wenjian

    2017-01-25

    Light-induced cell detachment shows much potential in in vitro cell culture and calls for high-performance light-responsive films. In this study, a smooth and dense SiO2/TiO2 nanocomposite thin film with thickness of around 250 nm was first fabricated on H2O2 treated polystyrene (PS) substrate via a low-temperature sol-gel method. It was observed that the film could well-adhere on the PS surface and the bonding strength became increasingly high with the increase of SiO2 content. The peeling strength and shear strength reached 3.05 and 30.02 MPa, respectively. It was observed the surface of the film could transform into superhydrophilic upon 20 min illumination of ultraviolet with a wavelength of 365 nm (UV365). In cell culture, cells, i.e., NIH3T3 and MC3T3-E1 cells, cultured on SiO2/TiO2 nanocomposite film were easily detached after 10 min of UV365 illumination; the detachment rates reached 90.8% and 88.6%, respectively. Correspondingly, continuous cell sheets with good viability were also easily obtained through the same way. The present work shows that SiO2/TiO2 nanocomposite thin film could be easily prepared on polymeric surface at low temperature. The corresponding film exhibits excellent biocompatibility, high bonding strength, and good light responses. It could be a good candidate for the surface of cell culture utensils with light-induced cell detachment property.

  4. images_template

    Data.gov (United States)

    National Aeronautics and Space Administration — Images for the website template go here. It will not change their names or locations, but will hopefully help to organize them. Oh, but for a directory structure...

  5. The Trouble With Templates

    CERN Document Server

    Sampson, Laura; Yunes, Nicolas

    2013-01-01

    Waveform templates are a powerful tool for extracting and characterizing gravitational wave signals, acting as highly restrictive priors on the signal morphologies that allow us to extract weak events buried deep in the instrumental noise. The templates map the waveform shapes to physical parameters, thus allowing us to produce posterior probability distributions for these parameters. However, there are attendant dangers in using highly restrictive signal priors. If strong field gravity is not accurately described by General Relativity (GR), then using GR templates may result in fundamental bias in the recovered parameters, or even worse, a complete failure to detect signals. Here we study such dangers, concentrating on three distinct possibilities. First, we show that there exist modified theories compatible with all existing tests that would fail to be detected by the LIGO/Virgo network using searches based on GR templates, but which would be detected using a one parameter post-Einsteinian extension. Second...

  6. Joomla! 3 template essentials

    CERN Document Server

    Frankowski, Pawel

    2013-01-01

    Using this hands-on, step-by step tutorial filled with practical examples, the readers will be able to create beautiful templates and themes for your websites that will make them stand out from others.This book is written for all of you who wish to create your own unique templates for Joomla! 3.x. This book can be used by Joomla! administrators or visual designers (with no programming experience) or those of you who are used to working with common web developer tools like HTML/CSS editors for coding purposes. You would need basic knowledge of Joomla! and some knowledge of CSS and HTML.

  7. Computing layouts with deformable templates

    KAUST Repository

    Peng, Chihan

    2014-07-27

    In this paper, we tackle the problem of tiling a domain with a set of deformable templates. A valid solution to this problem completely covers the domain with templates such that the templates do not overlap. We generalize existing specialized solutions and formulate a general layout problem by modeling important constraints and admissible template deformations. Our main idea is to break the layout algorithm into two steps: a discrete step to lay out the approximate template positions and a continuous step to refine the template shapes. Our approach is suitable for a large class of applications, including floorplans, urban layouts, and arts and design. Copyright © ACM.

  8. Gamma-irradiation and UV-C light-induced lipid peroxidation: a Fourier transform-infrared absorption spectroscopic study.

    Science.gov (United States)

    Kinder, R; Ziegler, C; Wessels, J M

    1997-05-01

    Fourier transform-infrared spectroscopy of dry, multibilayer films has been used to study gamma-radiation and UV-C light induced lipid peroxidation in 1,2-dilinoleoyl-sn-glycero-3-phosphocholine liposomes. The observed spectral changes were compared with the results obtained from measurement of hydroperoxides, conjugated dienes and to the formation of thiobarbituric acid reactive substances, such as malondialdehyde (MDA) or MDA-like substances. Upon irradiation a decrease in intensity of the asymmetric C - H stretching vibration (va(CH2)) of the isolated cis C = C - H groups (3010 cm-1) was observed. Directly correlated with the decrease of the va(CH2) absorption was a shift of the asymmetric phosphate ester stretching vibration (va(P = O)) towards smaller wavenumbers (1260-->1244 cm-1), indicating that the lipid peroxidation induced molecular alterations in the fatty acid chains influence the packing of the phospholipids in dry multibilayer films. In addition, the formation of a new absorption band at 1693 cm-1 could be detected, the intensity of which was comparable with the formation of thiobarbituric acid reactive substances and, therefore, attributed to the (C = O) stretching of alpha, beta unsaturated aldehydes. Dose-dependent studies using ionizing radiation showed that the decrease of va(CH2) was directly correlated with an increase in absorption of the conjugated dienes at 234 nm and with the formation of hydroperoxides suggesting that the absorption at 3010 cm-1 is solely due to isolated cis C = C - H groups and hence subject to the early stages of the radical chain reaction. UV-C light induced lipid peroxidation revealed a non-linear decrease of I3010, which was directly correlated with the formation of hydroperoxides. The observed early saturation of the conjugated dienes was attributed to an early photodecomposition of the conjugated double bonds.

  9. Template Composite Dark Matter

    DEFF Research Database (Denmark)

    Drach, Vincent; Hietanen, Ari; Pica, Claudio

    2015-01-01

    We present a non perturbative study of SU(2) gauge theory with two fundamental Dirac flavours. We discuss how the model can be used as a template for composite Dark Matter (DM). We estimate one particular interaction of the DM candidate with the Standard Model : the interaction through photon...

  10. Biometric template revocation

    Science.gov (United States)

    Arndt, Craig M.

    2004-08-01

    Biometric are a powerful technology for identifying humans both locally and at a distance. In order to perform identification or verification biometric systems capture an image of some biometric of a user or subject. The image is then converted mathematical to representation of the person call a template. Since we know that every human in the world is different each human will have different biometric images (different fingerprints, or faces, etc.). This is what makes biometrics useful for identification. However unlike a credit card number or a password to can be given to a person and later revoked if it is compromised and biometric is with the person for life. The problem then is to develop biometric templates witch can be easily revoked and reissued which are also unique to the user and can be easily used for identification and verification. In this paper we develop and present a method to generate a set of templates which are fully unique to the individual and also revocable. By using bases set compression algorithms in an n-dimensional orthogonal space we can represent a give biometric image in an infinite number of equally valued and unique ways. The verification and biometric matching system would be presented with a given template and revocation code. The code will then representing where in the sequence of n-dimensional vectors to start the recognition.

  11. Light induced polymerization of resin composite restorative materials

    Directory of Open Access Journals (Sweden)

    Blažić Larisa

    2004-01-01

    Full Text Available Introduction Dimensional stability of polymer-based dental materials is compromised by polymerization reaction of the monomer. The conversion into a polymer is accompanied by a closer packing of molecules, which leads to volume reduction called curing contraction or polymerization shrinkage. Curing contraction may break the adhesion between the adhesive system and hard tooth tissues forming micrographs which may result in marginal deterioration, recurrent caries and pulp injury. Polymerization shrinkage of resin-based restorative dental materials Polymerization of the organic phase (monomer molecules of resin-based dental materials causes shrinkage. The space occupied by filler particles is not associated with polymerization shrinkage. However, high filler loading within certain limits, can contribute to a lesser curing contraction. Polymerization shrinkage stress and stress reduction possibilities Polymerization shrinkage stress of polymer-based dental resins can be controlled in various ways. The adhesive bond in tooth-restoration interface guides the contraction forces to cavity walls. If leakage occurs, complications like secondary caries and pulpal irritation may jeopardize the longevity of a restoration. Stress relieve can be obtained by modifications of the monomer and photoinitiator, or by specially designed tooth preparation and application of bases and liners of low modulus of elasticity. The polymerization contraction can be compensated by water absorption due to oral cavity surrounding. The newest approach to stress relief is based on modulation of polymerization initiation. Conclusion This work deals with polymerization contraction and how to achieve leak-proof restoration. Restorative techniques that may reduce the negative effect of polymerization shrinkage stress need further research in order to confirm up-to-date findings.

  12. Introducing Dunaliella LIP promoter containing light-inducible motifs improves transgenic expression in Chlamydomonas reinhardtii.

    Science.gov (United States)

    Baek, Kwangryul; Lee, Yew; Nam, Onyou; Park, Seunghye; Sim, Sang Jun; Jin, EonSeon

    2016-03-01

    Promoter of the light-inducible protein gene (LIP) of Dunaliella was recently isolated in our laboratory. The aim of this work is to find the light-inducible motif in the Dunaliella LIP promoter and verify its regulatory motif with a Gaussia luciferase reporter gene transformed in Chlamydomonas reinhardtii. 400 bp upstream to the translational start site of the Dunaliella LIP gene was gradually truncated and analyzed for the luciferase expression. Furthermore, this promoter comprising duplicated or triplicated light-responsive motifs was tested for its augmentation of light response. Two putative light-responsive motifs, GT-1 binding motif and sequences over-represented in light-repressed promoters (SORLIP) located in the 200 bp LIP promoter fragment were analyzed for their light responsibility. It is turned out that SORLIP was responsible for the light-inducible activity. With the copy number of SORLIP up to three showed stronger high light response compared with the native LIP promoter fragment. Therefore, we found a light-responsive DNA motif operating in Chlamydomonas and confirm a synthetic promoter including this motif displayed light inducibility in heterologously transformed green algae for the first time. This light-inducible expression system will be applied to various area of algal research including algal biotechnology.

  13. Light-Induced Phosphorylation of Crystallins in the Retinal Pigment Epithelium

    Science.gov (United States)

    Lee, Hyunju; Chung, Hyewon; Lee, Sung Haeng; Jahng, Wan Jin

    2017-01-01

    Protein phosphorylations have essential regulatory roles in visual signaling. Previously, we found that phosphorylation of several proteins in the retina and the retinal pigment epithelium (RPE) is involved in anti-apoptotic signaling under oxidative stress conditions, including light exposure. In this study, we used a phosphoprotein enrichment strategy to evaluate the light-induced phosphoproteome of primary bovine RPE cells. Phosphoprotein-enriched extracts from bovine RPE cells exposed to light or dark conditions for 1 hour were separated by 2D SDS-PAGE. Serine and tyrosine phosphorylation were visualized by 2D phospho western blotting and specific phosphorylation sites were analyzed by tandem mass spectrometry. Light induced a marked increase in tyrosine phosphorylation of beta crystallin A3 and A4. The most abundant light-induced up-regulated phosphoproteins were crystallins of 15–25-kDa, including beta crystallin S and zeta crystallin. Phosphorylation of beta crystallin suggests an anti-apoptotic chaperone function in the RPE. Other chaperones, cytoskeletal proteins, and proteins involved in energy balance were expressed at higher levels in the dark. A detailed analysis of RPE phosphoproteins provides a molecular basis for understanding light-induced signal transduction and anti-apoptosis mechanisms. Our data indicates that phosphorylation of crystallins likely represents an important mechanism for RPE shielding from physiological and pathophysiological light-induced oxidative injury. PMID:21094180

  14. Light-induced nonlinear effects on dispersion relation of ultracold Bose gas

    Institute of Scientific and Technical Information of China (English)

    胡正峰; 杜春光; 李师群

    2003-01-01

    We have investigated the optical properties of A-configuration ultracold dense Bose gas interacting with two laser pulses, which usually result in electromagnetically induced transparency. With the nonrelativistic quantum electrodynamics and taking into account the atomic dipole-dipole interaction and local field effect, we have derived the Maxwell-Bloch equations of the system. The dispersion relation of an ultracold Bose gas has been obtained and the light-induced nonlinear effects have been analysed. The light-induced nonlinear effects are different from the effects induced by two-body collision of Bose-Einstein condensation atoms which have a frequency shift of transparent window.

  15. Nanosecond dynamics of a gallium mirror's light-induced reflectivity change

    CERN Document Server

    Albanis, V; Emelyanov, V I; Fedotov, V A; MacDonald, K F; Petropoulos, P M; Richardson, D J; Zheludev, N I

    2000-01-01

    Transient pump-probe optical reflectivity measurements of the nano/microsecond dynamics of a fully reversible, light-induced, surface-assisted metallization of gallium interfaced with silica are reported. The metallization leads to a considerable increase in the interface's reflectivity when solid a-gallium is on the verge of melting. The reflectivity change was found to be a cumulative effect that grows with light intensity and pulse duration. The reflectivity relaxes back to that of alpha-gallium when the excitation is withdrawn in a time that increases critically at gallium's melting point. The effect is attributed to a non-thermal light-induced structural phase transition.

  16. Excitation of Light-Induced Acoustic Waves in Doped Lithium Niobate Crystals

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The phenomena of acoustic emission in doped lithium niobate crystals were observed in the process of light-induced quasi-breakdown. It is found that the ultrasonic waves introduce into the crystal have been modulated by the low frequency acoustic waves. Its frequency increases with the rise of the intensity of incident light and its jump period of breakdown is the same as that of the photovoltaic current Ic, the change of light-induced refractive index Δn and the diffracted light intensity L. This effect was explained with the interaction of the three waves and resonant state theory. The experimental results and the theoretical analysis are in conformity.

  17. In search of templates

    OpenAIRE

    Gobet, F.; Jackson, S

    2001-01-01

    This paper explores, both wit This study reflects a recent shift towards the study of early stages of expert memory acquisition for chess positions. Over the course of fifteen sessions, two subjects who knew virtually nothing about the game of chess were trained to memorise positions. Increase in recall performance and chunk size was captured by power functions, confirming predictions made by the template theory (Gobet & Simon, 1996, 1998, 2000). The human data was compared to that of a compu...

  18. Light-Induced Local Heating for Thermophoretic Manipulation of DNA in Polymer Micro- and Nanochannels

    DEFF Research Database (Denmark)

    Thamdrup, Lasse Højlund; Larsen, Niels Bent; Kristensen, Anders

    2010-01-01

    We present a method for making polymer chips with a narrow-band near-infrared absorber layer that enables light-induced local heating of liquids inside fluidic micro- and nanochannels fabricated by thermal imprint in polymethyl methacrylate. We have characterized the resulting liquid temperature...

  19. What goes down must come up: symmetry in light-induced migration behaviour of Daphnia

    NARCIS (Netherlands)

    Van Gool, E.; Ringelberg, J.

    2003-01-01

    During a short period of the year, Daphnia may perform a phenotypically induced diel vertical migration. For this to happen, light-induced swimming reactions must be enhanced both at dawn and at dusk. Enhanced swimming in response to light intensity increase can be elicited by fish-associated kairom

  20. The formation of light-induced gratings in the rigid eosine K solution in gelatin

    Science.gov (United States)

    Vorob'ev, A. A.; Kolchanova, S. A.; Sizykh, A. G.; Sul'Kis, I. G.

    1992-03-01

    The mechanism of the formation of light-induced amplitude gratings in the rigid eosine K solution in gelatin is investigated. It is shown that spatial modulation of the absorptance of the recording medium is caused by the transformation of the dye into a colorless form in the process of photosensitized proton transfer from gelatin to the eosine.

  1. Photopolymerization-Induced Two-Beam Coupling and Light-Induced Scattering in Polymethyl Methacrylate

    Institute of Scientific and Technical Information of China (English)

    LI Wei; GAO Feng; TANG Bai-Quan; Christian Pruner; ZHANG Xin-Zheng; SHI Yan-Li; XU Jing-Jun; QIAO Hai-Jun; WU Qiang; Romano A. Rupp; LOU Ci-Bo; WANG Zhen-Hua

    2008-01-01

    @@ Light amplification due to two-beam coupling is realized in doped polymethyl methacrylate (PMMA) glasses. A coupling gain as large as 14 cm-1 is obtained. The dynamic behaviour of absorption and light-induced scattering due to the process of photopolymerization are also studied. The results show that the amplification and its dynamic process enable possible applications of PMMA in optical devices.

  2. Early-time photodynamics of ruthenium-based photocatalysts for light-induced hydrogen generation

    NARCIS (Netherlands)

    Pan, Qing

    2016-01-01

    This thesis aims to provide a fundamental understanding of the early-time photodynamics of a series of Ru/M (M = Pd or Pt) bimetallic photocatalysts for light-induced hydrogen generation. This class of complexes adopts a general structure involving a Ru(II) center coordinated to two peripheral ligan

  3. Phototropins mediate blue and red light-induced chloroplast movements in Physcomitrella patens.

    Science.gov (United States)

    Kasahara, Masahiro; Kagawa, Takatoshi; Sato, Yoshikatsu; Kiyosue, Tomohiro; Wada, Masamitsu

    2004-07-01

    Phototropin is the blue-light receptor that mediates phototropism, chloroplast movement, and stomatal opening in Arabidopsis. Blue and red light induce chloroplast movement in the moss Physcomitrella patens. To study the photoreceptors for chloroplast movement in P. patens, four phototropin genes (PHOTA1, PHOTA2, PHOTB1, and PHOTB2) were isolated by screening cDNA libraries. These genes were classified into two groups (PHOTA and PHOTB) on the basis of their deduced amino acid sequences. Then phototropin disruptants were generated by homologous recombination and used for analysis of chloroplast movement. Data revealed that blue light-induced chloroplast movement was mediated by phototropins in P. patens. Both photA and photB groups were able to mediate chloroplast avoidance, as has been reported for Arabidopsis phot2, although the photA group contributed more to the response. Red light-induced chloroplast movement was also significantly reduced in photA2photB1photB2 triple disruptants. Because the primary photoreceptor for red light-induced chloroplast movement in P. patens is phytochrome, phototropins may be downstream components of phytochromes in the signaling pathway. To our knowledge, this work is the first to show a function for the phototropin blue-light receptor in a response to wavelengths that it does not absorb.

  4. Light induced electrical and macroscopic changes in hydrogenated polymorphous silicon solar cells

    Directory of Open Access Journals (Sweden)

    Roca i Cabarrocas P.

    2012-07-01

    Full Text Available We report on light-induced electrical and macroscopic changes in hydrogenated polymorphous silicon (pm-Si:H PIN solar cells. To explain the particular light-soaking behavior of such cells – namely an increase of the open circuit voltage (Voc and a rapid drop of the short circuit current density (Jsc – we correlate these effects to changes in hydrogen incorporation and structural properties in the layers of the cells. Numerous techniques such as current-voltage characteristics, infrared spectroscopy, hydrogen exodiffusion, Raman spectroscopy, atomic force microscopy, scanning electron microscopy and spectroscopic ellipsometry are used to study the light-induced changes from microscopic to macroscopic scales (up to tens of microns. Such comprehensive use of complementary techniques lead us to suggest that light-soaking produces the diffusion of molecular hydrogen, hydrogen accumulation at p-layer/substrate interface and localized delamination of the interface. Based on these results we propose that light-induced degradation of PIN solar cells has to be addressed from not only as a material issue, but also a device point of view. In particular we bring experimental evidence that localized delamination at the interface between the p-layer and SnO2 substrate by light-induced hydrogen motion causes the rapid drop of Jsc.

  5. Light induced electrical and macroscopic changes in hydrogenated polymorphous silicon solar cells

    Science.gov (United States)

    Kim, K. H.; Johnson, E. V.; Abramov, A.; Cabarrocas, P. Roca i.

    2012-07-01

    We report on light-induced electrical and macroscopic changes in hydrogenated polymorphous silicon (pm-Si:H) PIN solar cells. To explain the particular light-soaking behavior of such cells - namely an increase of the open circuit voltage (Voc) and a rapid drop of the short circuit current density (Jsc) - we correlate these effects to changes in hydrogen incorporation and structural properties in the layers of the cells. Numerous techniques such as current-voltage characteristics, infrared spectroscopy, hydrogen exodiffusion, Raman spectroscopy, atomic force microscopy, scanning electron microscopy and spectroscopic ellipsometry are used to study the light-induced changes from microscopic to macroscopic scales (up to tens of microns). Such comprehensive use of complementary techniques lead us to suggest that light-soaking produces the diffusion of molecular hydrogen, hydrogen accumulation at p-layer/substrate interface and localized delamination of the interface. Based on these results we propose that light-induced degradation of PIN solar cells has to be addressed from not only as a material issue, but also a device point of view. In particular we bring experimental evidence that localized delamination at the interface between the p-layer and SnO2 substrate by light-induced hydrogen motion causes the rapid drop of Jsc.

  6. A Deformable Template Model, with Special Reference to Elliptical Templates

    DEFF Research Database (Denmark)

    Hobolth, Asger; Pedersen, Jan; Jensen, Eva Bjørn Vedel

    2002-01-01

    This paper suggests a high-level continuous image model for planar star-shaped objects. Under this model, a planar object is a stochastic deformation of a star-shaped template. The residual process, describing the difference between the radius-vector function of the template and the object...

  7. Light-Induced Bistability in Iron(III) Spin-Transition Compounds of 5 X-Salicylaldehyde Thiosemicarbazone (X=H, Cl, Br).

    Science.gov (United States)

    Yemeli, Eddy W T; Blake, Graeme R; Douvalis, Alexios P; Bakas, Thomas; Alberda van Ekenstein, Gert O R; van Koningsbruggen, Petra J

    2010-10-19

    The iron(III) spin-crossover compounds [Fe(Hthsa)(thsa)]⋅H2 O (1), [Fe(Hth5Clsa)(th5Clsa)2 ]⋅H2 O (2), and [Fe(Hth5Brsa)(th5Brsa)2 ]⋅H2 O (3) (H2 thsa=salicylaldehyde thiosemicarbazone, H2 th5Clsa=5-chlorosalicylaldehyde thiosemicarbazone, and H2 th5Brsa=5-bromosalicylaldehyde thiosemicarbazone) have been synthesized and their spin-transition properties investigated by magnetic susceptibility, Mössbauer spectroscopy, and differential scanning calorimetry measurements. The three compounds exhibit an abrupt spin transition with a thermal hysteresis effect. The more polarizable the substituent on the salicylaldehyde moiety, the more complete is the transition at room temperature with an increased degree of cooperativity. The molecular structures of 1 and 2 in the high-spin state are revealed. The occurrence of the light-induced excited-spin-state trapping phenomenon appears to be dependent on the substituent incorporated into the 5-position of the salicylaldehyde subunit. Whereas the compounds with an electron-withdrawing group (-Br or -Cl) exhibit light-induced trapped excited high-spin states with great longevity of metastability, the halogen-free compound does not, even though strong intermolecular interactions (such as hydrogen-bonding networks and π stacking) operate in the system. For compound 2, the surface level of photoconversion is less than 35 %. In contrast, compound 3 displays full photoexcitation.

  8. Templated quasicrystalline molecular layers

    Science.gov (United States)

    Smerdon, Joe; Young, Kirsty; Lowe, Michael; Hars, Sanger; Yadav, Thakur; Hesp, David; Dhanak, Vinod; Tsai, An-Pang; Sharma, Hem Raj; McGrath, Ronan

    2014-03-01

    Quasicrystals are materials with long range ordering but no periodicity. We report scanning tunneling microscopy (STM) observations of quasicrystalline molecular layers on five-fold quasicrystal surfaces. The molecules adopt positions and orientations on the surface consistent with the quasicrystalline ordering of the substrate. Carbon-60 adsorbs atop sufficiently-separated Fe atoms on icosahedral Al-Cu-Fe to form a unique quasicrystalline lattice whereas further C60 molecules decorate remaining surface Fe atoms in a quasi-degenerate fashion. Pentacene (Pn) adsorbs at tenfold-symmetric points around surface-bisected rhombic triacontahedral clusters in icosahedral Ag-In-Yb. These systems constitute the first demonstrations of quasicrystalline molecular ordering on a template. EPSRC EP/D05253X/1, EP/D071828/1, UK BIS.

  9. DNA-templated nanofabrication.

    Science.gov (United States)

    Becerril, Héctor A; Woolley, Adam T

    2009-02-01

    Nanofabrication, or the organizational control over matter at the nanometre scale, is an intriguing scientific challenge requiring multidisciplinary tools for its solution. DNA is a biomolecule that can be combined with other nanometre-scale entities through chemical self-assembly to form a broad variety of nanomaterials. In this tutorial review we present the principles that allow DNA to interact with other chemical species, and describe the challenges and potential applications of DNA as a template for making both biological and inorganic features with nanometre resolution. As such, this report should be of interest to chemists, surface and materials scientists, biologists, and nanotechnologists, as well as others who seek to use DNA in nanofabrication.

  10. An Efficient Light-Inducible P53 Expression System for Inhibiting Proliferation of Bladder Cancer Cell

    Science.gov (United States)

    Lin, Fan; Dong, Liang; Wang, Weiming; Liu, Yuchen; Huang, Weiren; Cai, Zhiming

    2016-01-01

    Optogenetic gene expression systems enable spatial-temporal modulation of gene transcription and cell behavior. Although applications in biomedicine are emerging, the utility of optogenetic gene switches remains elusive in cancer research due to the relative low gene activation efficiency. Here, we present an optimized CRISPR-Cas9-based light-inducible gene expression device that controls gene transcription in a dose-dependent manner. To prove the potential utility of this device, P53 was tested as a functional target in the bladder cancer cell models. It was illustrated that the light-induced P53 inhibited proliferation of 5637 and UMUC-3 cell effectively. The “light-on” gene expression system may demonstrate a novel therapeutic strategy for bladder cancer intervention. PMID:27766041

  11. Light-induced evaporative cooling in a magneto-optical trap

    Institute of Scientific and Technical Information of China (English)

    Ma Hong-Yu; Cheng Hua-Dong; Wang Yu-Zhu; Liu Liang

    2008-01-01

    This paper presents an experimental demonstration of light-induced evaporative cooling in a magneto-optical trap.An additional laser is used to interact with atoms at the edge of the atomic cloud in the trap.These atoms get an additional force and evaporated away from the trap by both the magnetic field and laser fields.The remaining atoms have lower kinetic energy and thus are cooled.It reports the measurements on the temperature and atomic number after the evaporative cooling with different parameters including the distance between the laser and the centre of the atomic cloud,the detuning,the intensity.The results show that the light-induced evaporative cooling is a way to generate an ultra-cold atom source.

  12. Effect Of Free Radical Quenchers On Dye-Mediated Laser Light Induced Photosensitization Of Leukemic Cells

    Science.gov (United States)

    Gulliya, Kirpal S.; Matthews, James L.; Fay, Joseph W.; Dowben, Robert M.

    1988-02-01

    The effect of free radical quenchers (ascorbate, catalase, and mannitol) on merocyanine 540 (MC540) mediated, laser light induced photolysis of human acute promyelocytic leukemia cell line (HL-60) was investigated. Results show that in the presence of human albumin (0.25%), dye-mediated (2014/m1), laser light induced photolysis of leukemic cells resulted in a 99.9999% cell kill. Seventy percent of the normal bone marrow cells survived the treatment. The addition of free radical quenchers prior to laser irradiation procedure increases the HL-60 cell survival. Increases of 5.5% and 4.4%, respectively, were observed in the presence of catalase and ascorbate or mannitol. In the presence of a mixture of catalase and mannitol or catalase and ascorbate, this increase in viability was not observed. However, the viability of normal bone marrow cells under these conditions also decreased from 70% to 63%. These findings may be useful in ex-vivo bone marrow purging.

  13. The effects of illumination and focal distance on light-induced fluorescence images in vitro.

    Science.gov (United States)

    Pretty, I A; Ellwood, P G; Davies, R M; Worthington, H W; Ellwood, R P

    2006-01-01

    When using quantitative light-induced fluorescence a number of factors can influence illumination level. The purpose of this study was to investigate, using a high-resolution camera and fibre-optic light source, the impact of illumination level and focal distance on common quantitative light-induced fluorescence outcomes. Twenty-four extracted teeth were examined using 6 illumination levels and 4 focal distances. Analysis was conducted using multiple linear regression models fitted to log DeltaQ, log DeltaF and log area with clustering of teeth and robust standard errors. Separate models were used for the different light and focal levels. The regression coefficients were significant for both DeltaQ and DeltaF but not area. Despite the significant regressions the actual effect was very small, and unlikely to confound clinical trial or practice results.

  14. Light-induced acoustic effect in LiNbO3:Fe:Ce crystals

    Institute of Scientific and Technical Information of China (English)

    Huang Wei; Wu Zhong-Kang; Wang Chang-Qing

    2005-01-01

    The phenomena of acoustic emission in LiNbO3:Fe:Ce crystals have been observed in the process of light-induced quasi-breakdown. It is found that the ultra-high frequency acoustic signal introduced into the crystal is modulated by the low frequency acoustic waves. Its frequency increases with the increase of the intensity of incident light and its jump period of breakdown is the same as that of the photovoltaic current Ic, the change of light-induced refractive index △n and the diffracted light intensity L. This phenomenon has been analysed in this paper, which is caused by the inverse piezoelectric strain effect of the jump of space charge field during the quasi-breakdown.

  15. Template-synthesized opal hydrogels

    Institute of Scientific and Technical Information of China (English)

    LI Jun; JI Lijun; RONG Jianhua; YANG Zhenzhong

    2003-01-01

    Opal hydrogels could be synthesized with polymer inverse opal template. A pH responsive opal N-iso- propylacrylamide/acrylic acid copolymerized hydrogel was prepared as an example. The ordered structure and response to pH were investigated. Through the sol-gel process of tetrabutyl titanate, opal titania was obtained with the opal hydrogel template.

  16. Effects of combined ketamine/xylazine anesthesia on light induced retinal degeneration in rats.

    Directory of Open Access Journals (Sweden)

    Blanca Arango-Gonzalez

    Full Text Available OBJECTIVES: To explore the effect of ketamine-xylazine anesthesia on light-induced retinal degeneration in rats. METHODS: Rats were anesthetized with ketamine and xylazine (100 and 5 mg, respectively for 1 h, followed by a recovery phase of 2 h before exposure to 16,000 lux of environmental illumination for 2 h. Functional assessment by electroretinography (ERG and morphological assessment by in vivo imaging (optical coherence tomography, histology (hematoxylin/eosin staining, TUNEL assay and immunohistochemistry (GFAP and rhodopsin staining were performed at baseline (ERG, 36 h, 7 d and 14 d post-treatment. Non-anesthetized animals treated with light damage served as controls. RESULTS: Ketamine-xylazine pre-treatment preserved retinal function and protected against light-induced retinal degeneration. In vivo retinal imaging demonstrated a significant increase of outer nuclear layer (ONL thickness in the non-anesthetized group at 36 h (p0.05, indicating a stabilizing and/or protective effect with regard to phototoxicity. Histology confirmed light-induced photoreceptor cell death and Müller cells gliosis in non-anesthetized rats, especially in the superior hemiretina, while ketamine-xylazine treated rats showed reduced photoreceptor cell death (TUNEL staining: p<0.001 after 7 d, thicker ONL and longer IS/OS. Fourteen days after light damage, a reduction of standard flash induced a-wave amplitudes and a-wave slopes (p = 0.01 and significant alterations in parameters of the scotopic sensitivity function (e.g. Vmax of the Naka Rushton fit p = 0.03 were observed in non-treated vs. ketamine-xylazine treated animals. CONCLUSIONS: Our results suggest that pre-treatment with ketamine-xylazine anesthesia protects retinas against light damage, reducing photoreceptor cell death. These data support the notion that anesthesia with ketamine-xylazine provides neuroprotective effects in light-induced cell damage.

  17. Effects of Combined Ketamine/Xylazine Anesthesia on Light Induced Retinal Degeneration in Rats

    Science.gov (United States)

    Bolz, Sylvia; Eslava-Schmalbach, Javier; Willmann, Gabriel; Zhour, Ahmad; Zrenner, Eberhart; Fischer, M. Dominik; Gekeler, Florian

    2012-01-01

    Objectives To explore the effect of ketamine-xylazine anesthesia on light-induced retinal degeneration in rats. Methods Rats were anesthetized with ketamine and xylazine (100 and 5 mg, respectively) for 1 h, followed by a recovery phase of 2 h before exposure to 16,000 lux of environmental illumination for 2 h. Functional assessment by electroretinography (ERG) and morphological assessment by in vivo imaging (optical coherence tomography), histology (hematoxylin/eosin staining, TUNEL assay) and immunohistochemistry (GFAP and rhodopsin staining) were performed at baseline (ERG), 36 h, 7 d and 14 d post-treatment. Non-anesthetized animals treated with light damage served as controls. Results Ketamine-xylazine pre-treatment preserved retinal function and protected against light-induced retinal degeneration. In vivo retinal imaging demonstrated a significant increase of outer nuclear layer (ONL) thickness in the non-anesthetized group at 36 h (p0.05), indicating a stabilizing and/or protective effect with regard to phototoxicity. Histology confirmed light-induced photoreceptor cell death and Müller cells gliosis in non-anesthetized rats, especially in the superior hemiretina, while ketamine-xylazine treated rats showed reduced photoreceptor cell death (TUNEL staining: p<0.001 after 7 d), thicker ONL and longer IS/OS. Fourteen days after light damage, a reduction of standard flash induced a-wave amplitudes and a-wave slopes (p = 0.01) and significant alterations in parameters of the scotopic sensitivity function (e.g. Vmax of the Naka Rushton fit p = 0.03) were observed in non-treated vs. ketamine-xylazine treated animals. Conclusions Our results suggest that pre-treatment with ketamine-xylazine anesthesia protects retinas against light damage, reducing photoreceptor cell death. These data support the notion that anesthesia with ketamine-xylazine provides neuroprotective effects in light-induced cell damage. PMID:22558200

  18. Spatial Symmetry Breaking in the Belousov-Zhabotinsky Reaction with Light-Induced Remote Communication

    Energy Technology Data Exchange (ETDEWEB)

    Hildebrand, M.; Skodt, H.; Showalter, K.

    2001-08-20

    Domains containing spiral waves form on a stationary background in a photosensitive Belousov-Zhabotinsky reaction with light-induced alternating nonlocal feedback. Complex behavior of colliding and splitting wave fragments is found with feedback radii comparable to the spiral wavelength. A linear stability analysis of the uniform stationary states in an Oregonator model reveals a spatial symmetry breaking instability. Numerical simulations show behavior in agreement with that found experimentally and also predict a variety of other new patterns.

  19. Identification of novel light-induced genes in the suprachiasmatic nucleus

    Directory of Open Access Journals (Sweden)

    Piontkivska Helen

    2007-11-01

    Full Text Available Abstract Background The transmission of information about the photic environment to the circadian clock involves a complex array of neurotransmitters, receptors, and second messenger systems. Exposure of an animal to light during the subjective night initiates rapid transcription of a number of immediate-early genes in the suprachiasmatic nucleus of the hypothalamus. Some of these genes have known roles in entraining the circadian clock, while others have unknown functions. Using laser capture microscopy, microarray analysis, and quantitative real-time PCR, we performed a comprehensive screen for changes in gene expression immediately following a 30 minute light pulse in suprachiasmatic nucleus of mice. Results The results of the microarray screen successfully identified previously known light-induced genes as well as several novel genes that may be important in the circadian clock. Newly identified light-induced genes include early growth response 2, proviral integration site 3, growth-arrest and DNA-damage-inducible 45 beta, and TCDD-inducible poly(ADP-ribose polymerase. Comparative analysis of promoter sequences revealed the presence of evolutionarily conserved CRE and associated TATA box elements in most of the light-induced genes, while other core clock genes generally lack this combination of promoter elements. Conclusion The photic signalling cascade in the suprachiasmatic nucleus activates an array of immediate-early genes, most of which have unknown functions in the circadian clock. Detected evolutionary conservation of CRE and TATA box elements in promoters of light-induced genes suggest that the functional role of these elements has likely remained the same over evolutionary time across mammalian orders.

  20. Making Deformable Template Models Operational

    DEFF Research Database (Denmark)

    Fisker, Rune

    2000-01-01

    Deformable template models are a very popular and powerful tool within the field of image processing and computer vision. This thesis treats this type of models extensively with special focus on handling their common difficulties, i.e. model parameter selection, initialization and optimization...... published during the Ph.D. project. To put these articles into the general context of deformable template models and to pass on an overview of the deformable template model literature, the thesis starts with a compact survey of the deformable template model literature with special focus on representation....... A proper handling of the common difficulties is essential for making the models operational by a non-expert user, which is a requirement for intensifying and commercializing the use of deformable template models. The thesis is organized as a collection of the most important articles, which has been...

  1. Light-induced melatonin suppression at night after exposure to different wavelength composition of morning light.

    Science.gov (United States)

    Kozaki, Tomoaki; Kubokawa, Ayaka; Taketomi, Ryunosuke; Hatae, Keisuke

    2016-03-11

    Bright nocturnal light has been shown to suppress melatonin secretion. However, bright light exposure during the day might reduce light-induced melatonin suppression at night. The human circadian system is sensitive to short wavelength light. This study evaluated the preventive effect of different wavelengths of daytime light on light-induced melatonin suppression at night. Twelve male subjects were exposed to various light conditions (dim, white, and bluish white light) between the hours of 09:00 and 10:30 (daytime light conditions). They were then exposed to light (300lx) again between 01:00 and 02:30 (night-time light exposure). Subjects provided saliva samples before (00:55) and after night-time light exposure (02:30). A two-tailed paired t-test yielded significant decrements in melatonin concentrations after night-time light exposure under daytime dim and white light conditions. No significant differences were found in melatonin concentrations between pre- and post-night-time light exposure with bluish-white light. Present findings suggest that daytime blue light exposure has an acute preventive impact on light-induced melatonin suppression in individuals with a general life rhythm (sleep/wake schedule). These findings may be useful for implementing artificial light environments for humans in, for example, hospitals and underground shopping malls to reduce health risks.

  2. Bond Issues.

    Science.gov (United States)

    Pollack, Rachel H.

    2000-01-01

    Notes trends toward increased borrowing by colleges and universities and offers guidelines for institutions that are considering issuing bonds to raise money for capital projects. Discussion covers advantages of using bond financing, how use of bonds impacts on traditional fund raising, other cautions and concerns, and some troubling aspects of…

  3. Inhibition by acrolein of light-induced stomatal opening through inhibition of inward-rectifying potassium channels in Arabidopsis thaliana.

    Science.gov (United States)

    Islam, Md Moshiul; Ye, Wenxiu; Matsushima, Daiki; Khokon, Md Atiqur Rahman; Munemasa, Shintaro; Nakamura, Yoshimasa; Murata, Yoshiyuki

    2015-01-01

    Acrolein is a reactive α,β-unsaturated aldehyde derived from lipid peroxides, which are produced in plants under a variety of stress. We investigated effects of acrolein on light-induced stomatal opening using Arabidopsis thaliana. Acrolein inhibited light-induced stomatal opening in a dose-dependent manner. Acrolein at 100 μM inhibited plasma membrane inward-rectifying potassium (Kin) channels in guard cells. Acrolein at 100 μM inhibited Kin channel KAT1 expressed in a heterologous system using Xenopus leaves oocytes. These results suggest that acrolein inhibits light-induced stomatal opening through inhibition of Kin channels in guard cells.

  4. Cloning nanocrystal morphology with soft templates

    Science.gov (United States)

    Thapa, Dev Kumar; Pandey, Anshu

    2016-08-01

    In most template directed preparative methods, while the template decides the nanostructure morphology, the structure of the template itself is a non-general outcome of its peculiar chemistry. Here we demonstrate a template mediated synthesis that overcomes this deficiency. This synthesis involves overgrowth of silica template onto a sacrificial nanocrystal. Such templates are used to copy the morphologies of gold nanorods. After template overgrowth, gold is removed and silver is regrown in the template cavity to produce a single crystal silver nanorod. This technique allows for duplicating existing nanocrystals, while also providing a quantifiable breakdown of the structure - shape interdependence.

  5. Correlation between SiH2/SiH and light-induced degradation of p-i-n hydrogenated amorphous silicon solar cells

    Science.gov (United States)

    Keya, Kimitaka; Kojima, Takashi; Torigoe, Yoshihiro; Toko, Susumu; Yamashita, Daisuke; Seo, Hyunwoong; Itagaki, Naho; Koga, Kazunori; Shiratani, Masaharu

    2016-07-01

    We have measured the hydrogen content ratio I SiH2/I SiH associated with Si-H2 and Si-H bonds in p-i-n (PIN) a-Si:H solar cells by Raman spectroscopy. With decreasing I SiH2/I SiH, the efficiency, short-circuit current density, open-circuit voltage, and fill factor of PIN a-Si:H solar cells after light soaking tend to increase. Namely, I SiH2/I SiH correlates well with light-induced degradation of the cells. While a single I-layer has a low I SiH2/I SiH of 0.03-0.09, a PIN cell has I SiH2/I SiH = 0.18 because many Si-H2 bonds exist in the P-layer and at the P/I interface of the PIN solar cells. To realize PIN solar cells with higher stability, we must suppress Si-H2 bond formation in the P-layer and at the P/I interface.

  6. Haptotropic Migration of Metal Templates on Arene Surfaces

    Institute of Scientific and Technical Information of China (English)

    K.H.Dtz; H.C.Jahr; J.Bennewitz; J.Dubarle-offner

    2007-01-01

    1 Results The chromium-templated benzannulation of arylcarbenes by alkynes provides a direct regio- and diastereoselective access to densely functionalized chromium arenes[1]. The chromium fragment undergoes a haptotropic migration along the π-face of the fused arenes which can be controlled by thermodynamics,by the substitution pattern of the arene and by the metal coligand sphere(See Scheme 1).The controlled regioselective labeling of benzene rings can be exploited in diastereoselective C-C bond forma...

  7. Templated Growth of Carbon Nanotubes

    Science.gov (United States)

    Siochik Emilie J. (Inventor)

    2007-01-01

    A method of growing carbon nanotubes uses a synthesized mesoporous si lica template with approximately cylindrical pores being formed there in. The surfaces of the pores are coated with a carbon nanotube precu rsor, and the template with the surfaces of the pores so-coated is th en heated until the carbon nanotube precursor in each pore is convert ed to a carbon nanotube.

  8. Phytochromes A and B mediate red-light-induced positive phototropism in roots.

    Science.gov (United States)

    Kiss, John Z; Mullen, Jack L; Correll, Melanie J; Hangarter, Roger P

    2003-03-01

    The interaction of tropisms is important in determining the final growth form of the plant body. In roots, gravitropism is the predominant tropistic response, but phototropism also plays a role in the oriented growth of roots in flowering plants. In blue or white light, roots exhibit negative phototropism that is mediated by the phototropin family of photoreceptors. In contrast, red light induces a positive phototropism in Arabidopsis roots. Because this red-light-induced response is weak relative to both gravitropism and negative phototropism, we used a novel device to study phototropism without the complications of a counteracting gravitational stimulus. This device is based on a computer-controlled system using real-time image analysis of root growth and a feedback-regulated rotatable stage. Our data show that this system is useful to study root phototropism in response to red light, because in wild-type roots, the maximal curvature detected with this apparatus is 30 degrees to 40 degrees, compared with 5 degrees to 10 degrees without the feedback system. In positive root phototropism, sensing of red light occurs in the root itself and is not dependent on shoot-derived signals resulting from light perception. Phytochrome (Phy)A and phyB were severely impaired in red-light-induced phototropism, whereas the phyD and phyE mutants were normal in this response. Thus, PHYA and PHYB play a key role in mediating red-light-dependent positive phototropism in roots. Although phytochrome has been shown to mediate phototropism in some lower plant groups, this is one of the few reports indicating a phytochrome-dependent phototropism in flowering plants.

  9. Light-induced morphological alteration in anthocyanin-accumulating vacuoles of maize cells

    Directory of Open Access Journals (Sweden)

    Grotewold Erich

    2005-05-01

    Full Text Available Abstract Background Plant pigmentation is affected by a variety of factors. Light, an important plant developmental signal, influences the accumulation of anthocyanins primarily through the activation of the transcription factors that regulate the flavonoid biosynthetic pathway. In this study, we utilized maize Black Mexican Sweet (BMS cells expressing the R and C1 regulators of anthocyanin biosynthesis from a light-insensitive promoter as a means to investigate the existence of additional levels of control of pigmentation by light. Results BMS cells expressing the R and C1 regulators from the CaMV 35S constitutive promoter accumulate anthocyanins when grown in complete darkness, suggesting that the transcription factors R and C1 are sufficient for the transcription of the genes corresponding to the structural enzymes of the pathway, with no requirement for additional light-induced regulators. Interestingly, light induces a "darkening" in the color of the purple anthocyanin pigmentation of transgenic BMS cells expressing R and C1. This change in the pigment hue is not associated with a variation in the levels or types of anthocyanins present, or with an alteration of the transcript levels of several flavonoid biosynthetic genes. However, cytological observations show that light drives unexpected changes in the morphology and distribution of the anthocyanins-containing vacuolar compartments. Conclusion By uncoupling the effect of light on anthocyanin accumulation, we have found light to induce the fusion of anthocyanin-containing vacuoles, the coalescence of anthocyanic vacuolar inclusion (AVI-like structures contained, and the spread of anthocyanins from the inclusions into the vacuolar sap. Similar light-induced alterations in vacuolar morphology are also evident in the epidermal cells of maize floral whorls accumulating anthocyanins. Our findings suggest a novel mechanism for the action of light on the vacuolar storage of anthocyanin.

  10. Light-induced scattering of light in NBS:Ce crystals

    Science.gov (United States)

    Voronov, V. V.; Dorosh, I. R.; Kuzminov, Iu. S.; Tkachenko, N. V.

    1980-11-01

    An experiment is described in which light-induced scattering of laser light was observed in Ce-doped (Sr/x/Ba/1-x/)/1-y/(Nb2O6)/y/ crystals with x = 0.61 and y = 0.4993. It is shown that the observed effect results from the holographic amplification of light scattered by crystal defects and that the observed asymmetry of the scattering is associated with the diffusion mechanism of hologram recording in crystals. A theoretical model of the scattering process is constructed for the diffusion recording mechanism.

  11. UV light induced photodegradation of organic dye by ZnO nanocatalysts

    Science.gov (United States)

    Sumesh, C. K.; Patel, Bhavin; Parekh, Kinnari

    2013-06-01

    Ultraviolet light induced photocatalytic activity of ZnO nanocatalyst prepared using a wet chemical precipitation route and mineralization of the methyl orange (MO) dye has been carried out in a photocatalytic reactor. The degradation of the MO was monitored spectrophotometrically and showed a decolorization efficiency of 92% after nine hours of irradiation in the MO-ZnO/UV light system. The blue shifting of maximum peak position of the MO and the formation of extra peak at 247 nm during irradiation time advances revealed that MO degrades in the form of intermediates during the photocatalytic process.

  12. Robust Measurement of Thin-Film Photovoltaic Modules Exhibiting Light-Induced Transients: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Deceglie, Michael, G.; Silverman, Timothy J.; Marion, Bill; Kurtz, Sarah R.

    2015-09-09

    Light-induced changes to the current-voltage characteristic of thin-film photovoltaic modules (i.e. light-soaking effects) frustrate the repeatable measurement of their operating power. We describe best practices for mitigating, or stabilizing, light-soaking effects for both CdTe and CIGS modules to enable robust, repeatable, and relevant power measurements. We motivate the practices by detailing how modules react to changes in different stabilization methods. We also describe and demonstrate a method for validating alternative stabilization procedures, such as those relying on forward bias in the dark. Reliable measurements of module power are critical for qualification testing, reliability testing, and power rating.

  13. Segregation of isotopes of heavy metals due to light-induced drift: results and problems

    CERN Document Server

    Sapar, A; Poolamäe, R; Sapar, L

    2007-01-01

    Atutov and Shalagin (1988) proposed light-induced drift (LID) as a physically well understandable mechanism to explain the formation of isotopic anomalies observed in CP stars. We generalized the theory of LID and applied it to diffusion of heavy elements and their isotopes in quiescent atmospheres of CP stars. Diffusional segregation of isotopes of chemical elements is described by the equations of continuity and diffusion velocity. Computations of the evolutionary sequences for abundances of mercury isotopes in several model atmospheres have been made using the Fortran 90 program SMART, composed by the authors. Results confirm predominant role of LID in separation of isotopes.

  14. Visualizations of Light-induced Refractive Index Changes in Photorefractive Crystals Employing Digital Holography

    Institute of Scientific and Technical Information of China (English)

    赵建林; 张鹏; 周俭波; 杨德兴; 杨东升; 李恩普

    2003-01-01

    We propose a novel approach to visualize the light-induced refractive index changes in photorefractive crystals employing digital holography. The holograms formed in a Mach-Zehnder interferometer are recorded by a twodimensional CCD camera. From these holograms, the phase differences, which contain the information of the index changes in photorefractive crystals, are determined by utilizing digital holographic interferometry. Then the two-dimensional visualizations of index changes in the crystals can be obtained. This method is successfully demonstrated in LiNbO3:Fe, KNSBN:Ce and SBN:Cr crystals.

  15. Robust measurement of thin-film photovoltaic modules exhibiting light-induced transients

    Science.gov (United States)

    Deceglie, Michael G.; Silverman, Timothy J.; Marion, Bill; Kurtz, Sarah R.

    2015-09-01

    Light-induced changes to the current-voltage characteristic of thin-film photovoltaic modules (i.e. light-soaking effects) frustrate the repeatable measurement of their operating power. We describe best practices for mitigating, or stabilizing, light-soaking effects for both CdTe and CIGS modules to enable robust, repeatable, and relevant power measurements. We motivate the practices by detailing how modules react to changes in different stabilization methods. We also describe and demonstrate a method for validating alternative stabilization procedures, such as those relying on forward bias in the dark. Reliable measurements of module power are critical for qualification testing, reliability testing, and power rating.

  16. Light-induced phenomena in one-component gas: The transport phenomena

    Science.gov (United States)

    Chermyaninov, I. V.; Chernyak, V. G.

    2016-09-01

    The article presents the theory of transport processes in a one-component gas located in the capillary under the action of resonant laser radiation and the temperature and pressure gradients. The expressions for the kinetic coefficients determining heat and mass transport in the gas are obtained on the basis of the modified Boltzmann equations for the excited and unexcited particles. The Onsager reciprocal relations for cross kinetic coefficients are proven for all Knudsen numbers and for any law interaction of gas particles with each other and boundary surface. Light-induced phenomena associated with the possible non-equilibrium stationary states of system are analyzed.

  17. Light-induced nonhomogeneity and gradient bending in photochromic liquid crystal elastomers

    Institute of Scientific and Technical Information of China (English)

    JIN; Lihua; JIANG; Xin; HUO; Yongzhong

    2006-01-01

    The recently reported opto-mechanical effect of some photochromic liquid crystal elastomers (LCEs) is studied. It is found that in such LCEs, material parameters such as the Young's modulus and the stress-free strains will become nonhomogeneous Analytical expressions for the dependence of the material parameters on the space variable and possibly on the time variable are obtained. Exponential dependence can be derived under certain approximations. As an example, the light-induced bending of a beam is studied. Two neutral planes are found in the beam. Thus, along the thickness of the beam,there are extensions in the upper and lower parts and contractions in the middle.

  18. Parental Bonding

    Directory of Open Access Journals (Sweden)

    T. Paul de Cock

    2014-08-01

    Full Text Available Estimating the early parent–child bonding relationship can be valuable in research and practice. Retrospective dimensional measures of parental bonding provide a means for assessing the experience of the early parent–child relationship. However, combinations of dimensional scores may provide information that is not readily captured with a dimensional approach. This study was designed to assess the presence of homogeneous groups in the population with similar profiles on parental bonding dimensions. Using a short version of the Parental Bonding Instrument (PBI, three parental bonding dimensions (care, authoritarianism, and overprotection were used to assess the presence of unobserved groups in the population using latent profile analysis. The class solutions were regressed on 23 covariates (demographics, parental psychopathology, loss events, and childhood contextual factors to assess the validity of the class solution. The results indicated four distinct profiles of parental bonding for fathers as well as mothers. Parental bonding profiles were significantly associated with a broad range of covariates. This person-centered approach to parental bonding has broad utility in future research which takes into account the effect of parent–child bonding, especially with regard to “affectionless control” style parenting.

  19. The LOLITA User-Definable Template Interface

    OpenAIRE

    Košmelj, Katarina

    2001-01-01

    The development of user-definable templates interfaces which allow the user to design new templates definitions in a user-friendly way is a new issue in the field of information extraction. The LOLITA user-definable templates interface allows the user to define new templates using sentences in natural language text with a few restrictions and formal elements. This approach is rather different from previous approaches to information extraction which require developers to code the template defi...

  20. Light-Induced Infrared Difference Spectroscopy in the Investigation of Light Harvesting Complexes

    Directory of Open Access Journals (Sweden)

    Alberto Mezzetti

    2015-07-01

    Full Text Available Light-induced infrared difference spectroscopy (IR-DS has been used, especially in the last decade, to investigate early photophysics, energy transfer and photoprotection mechanisms in isolated and membrane-bound light harvesting complexes (LHCs. The technique has the definite advantage to give information on how the pigments and the other constituents of the biological system (proteins, membranes, etc. evolve during a given photoreaction. Different static and time-resolved approaches have been used. Compared to the application of IR-DS to photosynthetic Reaction Centers (RCs, however, IR-DS applied to LHCs is still in an almost pioneering age: very often sophisticated techniques (step-scan FTIR, ultrafast IR or data analysis strategies (global analysis, target analysis, multivariate curve resolution are needed. In addition, band assignment is usually more complicated than in RCs. The results obtained on the studied systems (chromatophores and RC-LHC supercomplexes from purple bacteria; Peridinin-Chlorophyll-a-Proteins from dinoflagellates; isolated LHCII from plants; thylakoids; Orange Carotenoid Protein from cyanobacteria are summarized. A description of the different IR-DS techniques used is also provided, and the most stimulating perspectives are also described. Especially if used synergically with other biophysical techniques, light-induced IR-DS represents an important tool in the investigation of photophysical/photochemical reactions in LHCs and LHC-containing systems.

  1. Microscopic theory of light-induced deformation in amorphous side-chain azobenzene polymers.

    Science.gov (United States)

    Toshchevikov, V; Saphiannikova, M; Heinrich, G

    2009-04-16

    We propose a microscopic theory of light-induced deformation of side-chain azobenzene polymers taking into account the internal structure of polymer chains. Our theory is based on the fact that interaction of chromophores with the polarized light leads to the orientation anisotropy of azobenzene macromolecules which is accompanied by the appearance of mechanical stress. It is the first microscopic theory which provides the value of the light-induced stress larger than the yield stress. This result explains a possibility for the inscription of surface relief gratings in glassy side-chain azobenzene polymers. For some chemical architectures, elongation of a sample demonstrates a nonmonotonic behavior with the light intensity and can change its sign (a stretched sample starts to be uniaxially compressed), in agreement with experiments. Using a viscoplastic approach, we show that the irreversible strain of a sample, which remains after the light is switched off, decreases with increasing temperature and can disappear at certain temperature below the glass transition temperature. This theoretical prediction is also confirmed by recent experiments.

  2. Impaired Mitochondrial Energy Production Causes Light-Induced Photoreceptor Degeneration Independent of Oxidative Stress.

    Directory of Open Access Journals (Sweden)

    Manish Jaiswal

    2015-07-01

    Full Text Available Two insults often underlie a variety of eye diseases including glaucoma, optic atrophy, and retinal degeneration--defects in mitochondrial function and aberrant Rhodopsin trafficking. Although mitochondrial defects are often associated with oxidative stress, they have not been linked to Rhodopsin trafficking. In an unbiased forward genetic screen designed to isolate mutations that cause photoreceptor degeneration, we identified mutations in a nuclear-encoded mitochondrial gene, ppr, a homolog of human LRPPRC. We found that ppr is required for protection against light-induced degeneration. Its function is essential to maintain membrane depolarization of the photoreceptors upon repetitive light exposure, and an impaired phototransduction cascade in ppr mutants results in excessive Rhodopsin1 endocytosis. Moreover, loss of ppr results in a reduction in mitochondrial RNAs, reduced electron transport chain activity, and reduced ATP levels. Oxidative stress, however, is not induced. We propose that the reduced ATP level in ppr mutants underlies the phototransduction defect, leading to increased Rhodopsin1 endocytosis during light exposure, causing photoreceptor degeneration independent of oxidative stress. This hypothesis is bolstered by characterization of two other genes isolated in the screen, pyruvate dehydrogenase and citrate synthase. Their loss also causes a light-induced degeneration, excessive Rhodopsin1 endocytosis and reduced ATP without concurrent oxidative stress, unlike many other mutations in mitochondrial genes that are associated with elevated oxidative stress and light-independent photoreceptor demise.

  3. Light-induced degradation of storage starch in turions of Spirodela polyrhiza depends on nitrate.

    Science.gov (United States)

    Appenroth, Klaus-J; Ziegler, Paul

    2008-10-01

    Light induces both the germination of turions of the duckweed Spirodela polyrhiza and the degradation of the reserve starch stored in the turions. The germination photoresponse requires nitrate, and we show here that nitrate is also needed for the light-induced degradation of the turion starch. Ammonium cannot substitute for nitrate in this regard, and nitrate thus acts specifically as signal to promote starch degradation in the turions. Irradiation with continuous red light leads to starch degradation via auto-phosphorylation of starch-associated glucan, water dikinase (GWD), phosphorylation of the turion starch and enhanced binding of alpha-amylase to starch granules. The present study shows that all of these processes require the presence of nitrate, and that nitrate exerts its effect on starch degradation at a point between the absorption of light by phytochrome and the auto-phosphorylation of the GWD. Nitrate acts to coordinate carbon and nitrogen metabolism in germinating turions: starch will only be broken down when sufficient nitrogen is present to ensure appropriate utilization of the released carbohydrate. These data constitute the first report of control over the initiation of reserve starch degradation by nitrate.

  4. Preparation of Hierarchical BiOBr Microspheres for Visible Light-Induced Photocatalytic Detoxification and Disinfection

    Directory of Open Access Journals (Sweden)

    Ayla Ahmad

    2016-01-01

    Full Text Available Photocatalytic degradation is a promising alternative to traditional wastewater treatment methods. Recently developed visible light-responsive photocatalyst, BiOBr, has attracted extensive attentions. Hereby, a detailed investigation of application of BiOBr to bacterial inactivation and organic pollutants degradation is reported. Hydrothermal catalyst was prepared using template-free method. While, for solvothermal synthesis, CTAB was used as a template. Results indicate a higher photocatalytic activity by the solvothermally prepared catalyst. Solvothermally prepared BiOBr exhibited high photocatalytic activities in both water detoxification and disinfection.

  5. Template switching between PNA and RNA oligonucleotides

    Science.gov (United States)

    Bohler, C.; Nielsen, P. E.; Orgel, L. E.; Miller, S. L. (Principal Investigator)

    1995-01-01

    The origin of the RNA world is not easily understood, as effective prebiotic syntheses of the components of RNA, the beta-ribofuranoside-5'-phosphates, are hard to envisage. Recognition of this difficulty has led to the proposal that other genetic systems, the components of which are more easily formed, may have preceded RNA. This raises the question of how transitions between one genetic system and another could occur. Peptide nucleic acid (PNA) resembles RNA in its ability to form double-helical complexes stabilized by Watson-Crick hydrogen bonding between adenine and thymine and between cytosine and guanine, but has a backbone that is held together by amide rather than by phosphodiester bonds. Oligonucleotides bases on RNA are known to act as templates that catalyse the non-enzymatic synthesis of their complements from activated mononucleotides, we now show that RNA oligonucleotides facilitate the synthesis of complementary PNA strands and vice versa. This suggests that a transition between different genetic systems can occur without loss of information.

  6. Biometric template transformation: a security analysis

    Science.gov (United States)

    Nagar, Abhishek; Nandakumar, Karthik; Jain, Anil K.

    2010-01-01

    One of the critical steps in designing a secure biometric system is protecting the templates of the users that are stored either in a central database or on smart cards. If a biometric template is compromised, it leads to serious security and privacy threats because unlike passwords, it is not possible for a legitimate user to revoke his biometric identifiers and switch to another set of uncompromised identifiers. One methodology for biometric template protection is the template transformation approach, where the template, consisting of the features extracted from the biometric trait, is transformed using parameters derived from a user specific password or key. Only the transformed template is stored and matching is performed directly in the transformed domain. In this paper, we formally investigate the security strength of template transformation techniques and define six metrics that facilitate a holistic security evaluation. Furthermore, we analyze the security of two wellknown template transformation techniques, namely, Biohashing and cancelable fingerprint templates based on the proposed metrics. Our analysis indicates that both these schemes are vulnerable to intrusion and linkage attacks because it is relatively easy to obtain either a close approximation of the original template (Biohashing) or a pre-image of the transformed template (cancelable fingerprints). We argue that the security strength of template transformation techniques must consider also consider the computational complexity of obtaining a complete pre-image of the transformed template in addition to the complexity of recovering the original biometric template.

  7. Quantificational Etching of AAO Template

    Institute of Scientific and Technical Information of China (English)

    Guojun SONG; Dong CHEN; Zhi PENG; Xilin SHE; Jianjiang LI; Ping HAN

    2007-01-01

    Ni nanowires were prepared by electrodeposition in porous anodized aluminum oxide (AAO) template from a composite electrolyte solution. Well-ordered Ni nanowire arrays with controllable length were then made by the partial removal of AAO using a mixture of phosphoric acid and chromic acid (6 wt pct H3PO4:1.8 wt pct H3CrO4). The images of Ni nanowire arrays were studied by scanning electron microscopy (SEM) to determine the relationship between etching time and the length of Ni nanowire arrays. The results indicate that the length of nanowires exposed from the template can be accurately controlled by controlling etching time.

  8. Nanoimprinted polymer chips for light induced local heating of liquids in micro- and nanochannels

    DEFF Research Database (Denmark)

    Thamdrup, Lasse Højlund; Pedersen, Jonas Nyvold; Flyvbjerg, Henrik

    2010-01-01

    A nanoimprinted polymer chip with a thin near-infrared absorber layer that enables light-induced local heating (LILH) of liquids inside micro- and nanochannels is presented. An infrared laser spot and corresponding hot-spot could be scanned across the device. Large temperature gradients yield...... thermophoretic forces, which are used to manipulate and stretch individual DNA molecules confined in nanochannels. The absorber layer consists of a commercially available phthalocyanine dye (Fujifilm), with a narrow absorption peak at approximately 775 nm, dissolved in SU-8 photoresist (Microchem Corp.). The 500...... nm thick absorber layer is spin-coated on a transparent substrate and UV exposed. Microand nanofluidic channels are defined by nanoimprint lithography in a 1.5 μm thick layer of low molecular weight polymethyl methacrylate (PMMA, Microchem Corp.), which is spin coated on top of the absorber layer. We...

  9. Improving poor fill factors for solar cells via light-induced plating

    Institute of Scientific and Technical Information of China (English)

    Xing Zhao; Jia Rui; Ding Wuchang; Meng Yanlong; Jin Zhi; Liu Xinyu

    2012-01-01

    Silicon solar cells are prepared following the conventional fabrication processes,except for the metallization firing process.The cells are divided into two groups with higher and lower fill factors,respectively.After light-induced plating (LIP),the fill factors of the solar cells in both groups with different initial values reach the same level.Scanning electron microscope (SEM) images are taken under the bulk silver electrodes,which prove that the improvement for cells with a poor factor after LIP should benefit from sufficient exploitation of the high density silver crystals formed during the firing process.Moreover,the application of LIP to cells with poor electrode contact performance,such as nanowire cells and radial junction solar cells,is proposed.

  10. Theory of light-induced effective magnetic field in Rashba ferromagnets

    Science.gov (United States)

    Qaiumzadeh, Alireza; Titov, Mikhail

    2016-07-01

    Motivated by recent experiments on all-optical magnetization reversal in conductive ferromagnetic thin films we use nonequilibrium formalism to calculate the effective magnetic field induced in a Rashba ferromagnet by a short laser pulse. The main contribution to the effect originates in the direct optical transitions between spin-split subbands. The resulting effective magnetic field is inversely proportional to the impurity scattering rate and can reach the amplitude of a few Tesla in the systems like Co/Pt bilayers. We show that the total light-induced effective magnetic field in ferromagnetic systems is the sum of two contributions: a helicity dependent term, which is an even function of magnetization, and a helicity independent term, which is an odd function of magnetization. The primary role of the spin-orbit interaction is to widen the frequency range for direct optical transitions.

  11. Combination of light-induced effect and gate bias stress in organic phototransistors

    Science.gov (United States)

    Liguori, R.; Sheets, W. C.; Bezzeccheri, E.; Facchetti, A.; Rubino, A.

    2016-05-01

    In this work, the photoresponse of pentacene-based thin film transistors fabricated with a photocurable polymer insulator was investigated under visible and ultraviolet illumination. A simple model was developed to distinguish a photoconductive and a photovoltaic effect, that is, a direct photocurrent and a current enhancement caused by a threshold voltage shift. The direction of the light-induced threshold translation is affected by measurement conditions (e.g. integration time and voltage range) and is related to the nature of the trap states, specifically those located in the pentacene film near the interface with the polymer. In particular, it was shown that, thanks to this phenomenon, the photosensitivity of the fabricated phototransistors could be modulated by the gate bias applied during illumination.

  12. Visible light induced oxidation of water by rare earth manganites, cobaltites and related oxides

    Science.gov (United States)

    Naidu, B. S.; Gupta, Uttam; Maitra, Urmimala; Rao, C. N. R.

    2014-01-01

    A study of the visible light induced oxidation of water by perovskite oxides of the formula LaMO3 (M = transition metal) has revealed the best activity with LaCoO3 which contains Co3+ in the intermediate-spin (IS) with one eg electron. Among the rare earth manganites, only orthorhombic manganites with octahedral Mn3+ ions exhibit good catalytic activity, but hexagonal manganites are poor catalysts. Interestingly, not only the perovskite rare earth cobaltites but also solid solutions of Co3+ in cubic rare earth sesquioxides exhibit catalytic activity comparable to LaCoO3, the Co3+ ion in all these oxides also being in the IS t2g5eg1 state.

  13. Repair of ultraviolet light-induced DNA damage in cholera bacteriophages

    Energy Technology Data Exchange (ETDEWEB)

    Palit, B.N.; Das, G.; Das, J. (Indian Inst. of Chemical Biology, Calcutta. Dept. of Biophysics)

    1983-08-01

    DNA repair-proficient and -deficient strains of Vibrio cholerae were used to examine host cell reactivation, Weigle reactivation and photoreactivation of u.v.-irradiated cholera bacteriophages. U.v. light-induced DNA damage in phages of different morphological and serological groups could be efficiently photoreactivated. Host cell reactivation of irradiated phages of different groups was different on the same indicator host. Phage phi149 was the most sensitive, and phi138 the most resistant to u.v. irradiation. While phi138 showed appreciable host cell reactivation, this was minimal for phi149. Attempts to demonstrate Weigle reactivation of u.v.-irradiated cholera phages were not successful, although u.v.-induced filamentation of host cells was observed.

  14. Visible light induced ocular delayed bioluminescence as a possible origin of negative afterimage

    CERN Document Server

    Bokkon, I; Wang, C; Dai, J; Salari, V; Grass, F; Antal, I

    2011-01-01

    The delayed luminescence of biological tissues is an ultraweak reemission of absorbed photons after exposure to external monochromatic or white light illumination. Recently, Wang, B\\'okkon, Dai and Antal (Brain Res. 2011) presented the first experimental proof of the existence of spontaneous ultraweak biophoton emission and visible light induced delayed ultraweak photon emission from in vitro freshly isolated rat's whole eye, lens, vitreous humor and retina. Here, we suggest that the photobiophysical source of negative afterimage can also occur within the eye by delayed bioluminescent photons. In other words, when we stare at a colored (or white) image for few seconds, external photons can induce excited electronic states within different parts of the eye that is followed by a delayed reemission of absorbed photons for several seconds. Finally, these reemitted photons can be absorbed by nonbleached photoreceptors that produce a negative afterimage. Although this suggests the photobiophysical source of negativ...

  15. Light-Induced Reversible Self-Assembly of Gold Nanoparticles Surface-Immobilized with Coumarin Ligands.

    Science.gov (United States)

    He, Huibin; Feng, Miao; Chen, Qidi; Zhang, Xinqi; Zhan, Hongbing

    2016-01-18

    A novel light-induced reversible self-assembly (LIRSA) system is based on the reversible photodimerization and photocleavage of coumarin groups on the surface of gold nanoparticles (AuNPs) in THF solution. Facilitated by coumarin groups, light irradiation at 365 nm triggers the stable assembly of monodisperse AuNPs; the resulting self-assembly system can be disassembled back to the disassembled state by a relatively short exposure to benign UV light. The reversible self-assembly cycle can be repeated 4 times. A specific concentration range of coumarin ligand and the THF solvent were identified to be the two predominant factors that contribute to the LIRSA of AuNPs. This is the first successful application of reversible photodimerization based on a coumarin derivative in the field of AuNP LIRSA. This LIRSA system may provide unique opportunities for the photoregulated synthesis of many adjustable nanostructures and devices.

  16. Modeling of coherent ultrafast magneto-optical experiments: Light-induced molecular mean-field model

    Energy Technology Data Exchange (ETDEWEB)

    Hinschberger, Y. [Instituto de Física dos Materiais da Universidade do Porto, Departamento de Física et Astronomia, Rua do campo Alegre, 687, 4169-007 Porto (Portugal); Hervieux, P.-A. [Institut de Physique et Chimie des Matériaux de Strasbourg, Université de Strasbourg, CNRS UMR 7504 BP 43 - F-67034 Strasbourg Cedex 2 (France)

    2015-12-28

    We present calculations which aim to describe coherent ultrafast magneto-optical effects observed in time-resolved pump-probe experiments. Our approach is based on a nonlinear semi-classical Drude-Voigt model and is used to interpret experiments performed on nickel ferromagnetic thin film. Within this framework, a phenomenological light-induced coherent molecular mean-field depending on the polarizations of the pump and probe pulses is proposed whose microscopic origin is related to a spin-orbit coupling involving the electron spins of the material sample and the electric field of the laser pulses. Theoretical predictions are compared to available experimental data. The model successfully reproduces the observed experimental trends and gives meaningful insight into the understanding of magneto-optical rotation behavior in the ultrafast regime. Theoretical predictions for further experimental studies are also proposed.

  17. Spontaneous and light-induced photon emission from intact brains of chick embryos

    Institute of Scientific and Technical Information of China (English)

    张锦珠; 于文斗; 孙彤

    1997-01-01

    Photon emission (PE) and light-induced photon emission(LPE) of intact brains isolated from chick embryos have been measured by using the single photon counting device. Experimental results showed that the intensi-ty level of photon emission was detected to be higher from intact brain than from the medium in which the brain was immerged during measuring, and the emission intensity was related to the developmental stages, the healthy situation of the measured embryos, and the freshness of isolated brains as well. After white light illumination, a short-life de-layed emission from intact brains was observed, and its relaxation behavior followed a hyperbolic rather than an expo-nential law. According to the hypothesis of biophoton emission originating from a delocalized coherent electromagnetic field and Frohlich’s idea of coherent long-range interactions in biological systems, discussions were made on the signifi-cance of photon emission in studying cell communication, biological regulation, living system’

  18. Light-induced changes in bottled white wine and underlying photochemical mechanisms.

    Science.gov (United States)

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

    2017-03-04

    Bottled white wine may be exposed to UV-visible light for considerable periods of time before it is consumed. Light exposure may induce an off-flavor known as "sunlight" flavor, bleach the color of the wine, and/or increase browning and deplete sulfur dioxide. The changes that occur in bottled white wine exposed to light depend on the wine composition, the irradiation conditions, and the light exposure time. The light-induced changes in the aroma, volatile composition, color, and concentrations of oxygen and sulfur dioxide in bottled white wine are reviewed. In addition, the photochemical reactions thought to have a role in these changes are described. These include the riboflavin-sensitized oxidation of methionine, resulting in the formation of methanethiol and dimethyl disulfide, and the photodegradation of iron(III) tartrate, which gives rise to glyoxylic acid, an aldehyde known to react with flavan-3-ols to form yellow xanthylium cation pigments.

  19. Evaluation of dental enamel caries assessment using Quantitative Light Induced Fluorescence and Optical Coherence Tomography.

    Science.gov (United States)

    Maia, Ana Marly Araújo; de Freitas, Anderson Zanardi; de L Campello, Sergio; Gomes, Anderson Stevens Leônidas; Karlsson, Lena

    2016-06-01

    An in vitro study of morphological alterations between sound dental structure and artificially induced white spot lesions in human teeth, was performed through the loss of fluorescence by Quantitative Light-Induced Fluorescence (QLF) and the alterations of the light attenuation coefficient by Optical Coherence Tomography (OCT). To analyze the OCT images using a commercially available system, a special algorithm was applied, whereas the QLF images were analyzed using the software available in the commercial system employed. When analyzing the sound region against white spot lesions region by QLF, a reduction in the fluorescence intensity was observed, whilst an increase of light attenuation by the OCT system occurred. Comparison of the percentage of alteration between optical properties of sound and artificial enamel caries regions showed that OCT processed images through the attenuation of light enhanced the tooth optical alterations more than fluorescence detected by QLF System. QLF versus OCT imaging of enamel caries: a photonics assessment.

  20. Control of 1,3-cyclohexadiene photoisomerization using light-induced conical intersections

    CERN Document Server

    Kim, Jaehee; White, James L; Petrovic, Vladimir S; Martinez, Todd J; Bucksbaum, Philip H

    2011-01-01

    We have studied the photo-induced isomerization from 1,3-cyclohexadiene to 1,3,5-hexatriene in the presence of an intense ultrafast laser pulse. We find that the laser field can suppress isomerization if it is both polarized parallel to the excitation dipole and present 50 fs after the initial photoabsorption, at the time when the system is expected to be in the vicinity of a conical intersection that mediates this structural transition. A modified ab initio multiple spawning (AIMS) method shows that the laser induces a resonant coupling between the excited state and the ground state, which is a light-induced conical intersection. The theory accounts for the timing and direction of the effect.

  1. Batch and Flow Synthesis of Disulfides by Visible-Light-Induced TiO2 Photocatalysis.

    Science.gov (United States)

    Bottecchia, Cecilia; Erdmann, Nico; Tijssen, Patricia M A; Milroy, Lech-Gustav; Brunsveld, Luc; Hessel, Volker; Noël, Timothy

    2016-07-21

    A mild and practical method for the preparation of disulfides through visible-light-induced photocatalytic aerobic oxidation of thiols has been developed. The method involves the use of TiO2 as a heterogeneous photocatalyst. The catalyst's high stability and recyclability makes this method highly practical. The reaction can be substantially accelerated in a continuous-flow packed-bed reactor, which enables a safe and reliable scale-up of the reaction conditions. The batch and flow protocol described herein can be applied to a diverse set of thiol substrates for the preparation of homo- and hetero-dimerized disulfides. Furthermore, biocompatible reaction conditions (i.e., room temperature, visible light, neutral buffer solution, and no additional base) have been developed, which permits the rapid and chemoselective modification of densely functionalized peptide substrates without recourse to complex purification steps.

  2. Light-Induced Agglomeration and Diffusion of Different Particles with Optical Tweezers

    Institute of Scientific and Technical Information of China (English)

    LI Xue-Cong; SUN Xiu-Dong; LIU Hong-Peng; ZHANG Jian-Long

    2010-01-01

    @@ The dynamic process of light-induced agglomeration of carbon nanotubes(CNTs),C60 and Escherichia coli(E.coli)in aqueous solutions is demonstrated using an optical tweezers system.Based on the results,the diameter of the agglomerated region and the agglomeration rate increase with the increasing laser power.After the saturation-stable period,CNTs diffuse completely,C60 dusters only diffuse partially,and E.coli never diffuses in the agglomeration region.Theoretical analyses show that the molecular polarization and thermal diffusion of particles play crucial roles in the diffusion process.The results indicate the possibility of using light to aggregate and sort nanoparticles.

  3. Light-induced Notch activity controls neurogenic and gliogenic potential of neural progenitors.

    Science.gov (United States)

    Kim, Kyung-Tai; Song, Mi-Ryoung

    2016-10-28

    Oscillations in Notch signaling are essential for reserving neural progenitors for cellular diversity in developing brains. Thus, steady and prolonged overactivation of Notch signaling is not suitable for generating neurons. To acquire greater temporal control of Notch activity and mimic endogenous oscillating signals, here we adopted a light-inducible transgene system to induce active form of Notch NICD in neural progenitors. Alternating Notch activity saved more progenitors that are prone to produce neurons creating larger number of mixed clones with neurons and progenitors in vitro, compared to groups with no light or continuous light stimulus. Furthermore, more upper layer neurons and astrocytes arose upon intermittent Notch activity, indicating that dynamic Notch activity maintains neural progeny and fine-tune neuron-glia diversity.

  4. Origin of Light-Induced Spin-Correlated Radical Pairs in Cryptochrome

    Science.gov (United States)

    Weber, Stefan; Biskup, Till; Okafuji, Asako; Marino, Anthony R.; Berthold, Thomas; Link, Gerhard; Hitomi, Kenichi; Getzoff, Elizabeth D.; Schleicher, Erik; Norris, James R.

    2012-01-01

    Blue-light excitation of cryptochromes and homologs uniformly triggers electron transfer (ET) from the protein surface to the flavin-adenine dinucleotide (FAD) cofactor. A cascade of three conserved tryptophan residues has been considered to be critically involved in this photoreaction. If the FAD is initially in its fully oxidized (diamagnetic) redox state, light-induced ET via the tryptophan triad generates a series of short-lived spin-correlated radical pairs comprising an FAD radical and a tryptophan radical. Coupled doublet-pair species of this type have been proposed as the basis, e.g., of a biological magnetic compass in migratory birds, and were found critical for some cryptochrome functions in vivo. In this contribution, a cryptochrome-like protein (CRYD) derived from Xenopus laevis has been examined as a representative system. The terminal radical-pair state FAD•⋯W324• of X. laevis CRYD has been characterized in detail by time-resolved electron-paramagnetic resonance (TREPR) at X-band microwave frequency (9.68 GHz) and magnetic fields around 345 mT, and at Q-band (34.08 GHz) at around 1215 mT. Different precursor states – singlet versus triplet – of radical-pair formation have been considered in spectral simulations of the experimental electron-spin polarized TREPR signals. Conclusively, we present evidence for a singlet-state precursor of FAD•⋯W324• radical-pair generation because at both magnetic fields, where radical pairs were studied by TREPR, net-zero electron-spin polarization has been detected. Neither a spin-polarized triplet precursor nor a triplet at thermal equilibrium can explain such an electron-spin polarization. It turns out that a two-microwave-frequency TREPR approach is essential to draw conclusions on the nature of the precursor electronic states in light-induced spin-correlated radical pair formations. PMID:20684534

  5. Numerical study of light-induced phase behavior of smectic solids

    Science.gov (United States)

    Chung, Hayoung; Park, Jaesung; Cho, Maenghyo

    2016-10-01

    By the chemical cross-linking of rigid molecules, liquid crystal polymer (LCP) has been envisaged as a novel heterogeneous material due to the fact that various optical and geometric states of the liquid crystalline (LC) phases are projected onto the polymeric constituents. The phase behavior, which refers to the macroscopic shape change of LCP under thermotropic phase change, is a compelling example of such optical-mechanical coupling. In this study, the photomechanical behavior, which broadly refers to the thermal- or light-induced actuation of smectic solids, is investigated using three-dimensional nonlinear finite element analysis (FEA). First, the various phases of LC are considered as well as their relation to polymeric conformation defined by the strain energy of the smectic polymer; a comprehensive constitutive equation that bridges the strong, optomechanical coupling is then derived. Such photomechanical coupling is incorporated in the FEA considering geometric nonlinearity, which is vital to understanding the large-scale light-induced bending behavior of the smectic solid.To demonstrate the simulation capability of the present model, numerous examples of photomechanical deformations are investigated parametrically, either by changing the operating conditions such as stimuli (postsynthesis) or the intrinsic properties (presynthesis). When compared to nematic solids, distinguished behaviors due to smectic substances are found herein and discussed through experiments. The quasisoftness that bidirectionally couples microscopic variables to mechanical behavior is also explained, while considering the effect of nonlinearity. In addition to providing a comprehensive measure that could deepen the knowledge of photomechanical coupling, the use of the proposed finite element framework offers an insight into the design of light-responsive actuating systems made of smectic solids.

  6. Light-induced activation of class II cyclobutane pyrimidine dimer photolyases.

    Science.gov (United States)

    Okafuji, Asako; Biskup, Till; Hitomi, Kenichi; Getzoff, Elizabeth D; Kaiser, Gebhard; Batschauer, Alfred; Bacher, Adelbert; Hidema, Jun; Teranishi, Mika; Yamamoto, Kazuo; Schleicher, Erik; Weber, Stefan

    2010-05-04

    Light-induced activation of class II cyclobutane pyrimidine dimer (CPD) photolyases of Arabidopsis thaliana and Oryza sativa has been examined by UV/Vis and pulsed Davies-type electron-nuclear double resonance (ENDOR) spectroscopy, and the results compared with structure-known class I enzymes, CPD photolyase and (6-4) photolyase. By ENDOR spectroscopy, the local environment of the flavin adenine dinucleotide (FAD) cofactor is probed by virtue of proton hyperfine couplings that report on the electron-spin density at the positions of magnetic nuclei. Despite the amino-acid sequence dissimilarity as compared to class I enzymes, the results indicate similar binding motifs for FAD in the class II photolyases. Furthermore, the photoreduction kinetics starting from the FAD cofactor in the fully oxidized redox state, FAD(ox), have been probed by UV/Vis spectroscopy. In Escherichia coli (class I) CPD photolyase, light-induced generation of FADH from FAD(ox), and subsequently FADH(-) from FADH, proceeds in a step-wise fashion via a chain of tryptophan residues. These tryptophans are well conserved among the sequences and within all known structures of class I photolyases, but completely lacking from the equivalent positions of class II photolyase sequences. Nevertheless, class II photolyases show photoreduction kinetics similar to those of the class I enzymes. We propose that a different, but also effective, electron-transfer cascade is conserved among the class II photolyases. The existence of such electron transfer pathways is supported by the observation that the catalytically active fully reduced flavin state obtained by photoreduction is maintained even under oxidative conditions in all three classes of enzymes studied in this contribution.

  7. Bond Boom

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The Ministry of Finance recently kick-started a pilot program allowing local governments of Shanghai and Shenzhen,and Zhejiang and Guangdong provinces to issue bonds for the first time.How will the new policy affect fiscal capacities of local governments and the broader economy? What else should the country do to build a healthy bond market? Economists and experts discussed these issues in an interview with the Shanghai Securities Journal.Edited excerpts follow.

  8. Bond Boom

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The Ministry of Finance recently kick-started a pilot program allowing local governments of Shanghai and Shenzhen, and Zhejiang and Guangdong provinces to issue bonds for the first time. How will the new policy affect fiscal capacities of local governments and the broader economy? What else should the country do to build a healthy bond market? Economists and experts discussed these issues in an interview with the ShanghaiSecuritiesJournal. Edited excerpts follow:

  9. Progress of NIL template making

    Science.gov (United States)

    Yusa, Satoshi; Hiraka, Takaaki; Kobiki, Ayumi; Sasaki, Shiho; Itoh, Kimio; Toyama, Nobuhito; Kurihara, Masaaki; Mohri, Hiroshi; Hayashi, Naoya

    2007-05-01

    Nano-imprint lithography (NIL) has been counted as one of the lithography solutions for hp32nm node and beyond. Recently, the small line edge roughness (LER) as well as the potentially high resolution that will ensure no-OPC mask feature is attracting many researchers. The template making is one of the most critical issues for the realization of NIL. Especially when we think of a practical template fabrication process on a 65mm square format that is going to be the industry standard, the resolution of the template making process showed a limitation. We have achieved for the first time an hp22nm resolution on the 65nm template format. Both line and space patterns and hole patterns were well resolved. Regarding dot patterns, we still need improvement, but we have achieved resolution down to hp28nm. Although so far we cannot achieve these resolution limits of various pattern category at the same time on one substrate, an intermediate process condition showed sufficient uniformity both in lateral CD and in vertical depth. Global pattern image placement also showed sufficient numbers at this stage of lithography development. A 20nm feature (with a pitch of 80nm) showed sufficient imprint result.

  10. Supply-Chain Optimization Template

    Science.gov (United States)

    Quiett, William F.; Sealing, Scott L.

    2009-01-01

    The Supply-Chain Optimization Template (SCOT) is an instructional guide for identifying, evaluating, and optimizing (including re-engineering) aerospace- oriented supply chains. The SCOT was derived from the Supply Chain Council s Supply-Chain Operations Reference (SCC SCOR) Model, which is more generic and more oriented toward achieving a competitive advantage in business.

  11. Photocatalytic C-C Bond Cleavage and Amination of Cycloalkanols by Cerium(III) Chloride Complex.

    Science.gov (United States)

    Guo, Jing-Jing; Hu, Anhua; Chen, Yilin; Sun, Jianfeng; Tang, Haoming; Zuo, Zhiwei

    2016-12-05

    A general strategy for the cleavage and amination of C-C bonds of cycloalkanols has been achieved through visible-light-induced photoredox catalysis utilizing a cerium(III) chloride complex. This operationally simple methodology has been successfully applied to a wide array of unstrained cyclic alcohols, and represents the first example of catalytic C-C bond cleavage and functionalization of unstrained secondary cycloalkanols.

  12. Viral-templated Palladium Nanocatalysts

    Science.gov (United States)

    Yang, Cuixian

    Despite recent progress on nanocatalysis, there exist several critical challenges in simple and readily controllable nanocatalyst synthesis including the unpredictable particle growth, deactivation of catalytic activity, cumbersome catalyst recovery and lack of in-situ reaction monitoring. In this dissertation, two novel approaches are presented for the fabrication of viral-templated palladium (Pd) nanocatalysts, and their catalytic activities for dichromate reduction reaction and Suzuki Coupling reaction were thoroughly studied. In the first approach, viral template based bottom-up assembly is employed for the Pd nanocatalyst synthesis in a chip-based format. Specifically, genetically displayed cysteine residues on each coat protein of Tobacco Mosaic Virus (TMV) templates provide precisely spaced thiol functionalities for readily controllable surface assembly and enhanced formation of catalytically active Pd nanoparticles. Catalysts with the chip-based format allow for simple separation and in-situ monitoring of the reaction extent. Thorough examination of synthesis-structure-activity relationship of Pd nanoparticles formed on surface-assembled viral templates shows that Pd nanoparticle size, catalyst loading density and catalytic activity of viral-templated Pd nanocatalysts can be readily controlled simply by tuning the synthesis conditions. The viral-templated Pd nanocatalysts with optimized synthesis conditions are shown to have higher catalytic activity per unit Pd mass than the commercial Pd/C catalysts. Furthermore, tunable and selective surface assembly of TMV biotemplates is exploited to control the loading density and location of Pd nanocatalysts on solid substrates via preferential electroless deposition. In addition, the catalytic activities of surface-assembled TMV-templated Pd nanocatalysts were also investigated for the ligand-free Suzuki Coupling reaction under mild reaction conditions. The chip-based format enables simple catalyst separation and

  13. Low-cost fabrication of poly(methyl methacrylate) microchips using disposable gelatin gel templates.

    Science.gov (United States)

    Chen, Zhi; Yu, Zhengyin; Chen, Gang

    2010-06-15

    A simple method based on disposable gelatin gel templates has been developed for the low-cost fabrication of poly(methyl methacrylate) (PMMA) microfluidic chips. Gelatin was dissolved in glycerol aqueous solution under heat to prepare a thermally reversible impression material. The molten gel was then sandwiched between a glass plate and a SU-8 template bearing negative relief of microstructure. After cooling, the negative SU-8 template could be easily separated from the solidified gelatin gel and a layer of gelatin template bearing positive relief of the microstructure was left on the glass plate. Subsequently, prepolymerized methyl methacrylate molding solution containing a UV-initiator was sandwiched between the gel template and a PMMA plate and was allowed to polymerize under UV light to fabricate PMMA channel plate at room temperature. Complete microchips could be obtained by bonding the channel plates with covers using plasticizer-assisted thermal bonding at 90 degrees C. Gelatin gel template can be mass-produced and will find application in the mass production of PMMA microchips at low cost. The prepared microfluidic microchips have been successfully employed in the capillary electrophoresis analysis of several ions in connection with contactless conductivity detection.

  14. National Wildlife Refuge System Survey Protocol Template

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This template was developed for drafting National Wildlife Refuge System (NWRS) Survey Protocols. The template is arranged in the same order as the eight basic...

  15. Web Template Extraction Based on Hyperlink Analysis

    Directory of Open Access Journals (Sweden)

    Julián Alarte

    2015-01-01

    Full Text Available Web templates are one of the main development resources for website engineers. Templates allow them to increase productivity by plugin content into already formatted and prepared pagelets. For the final user templates are also useful, because they provide uniformity and a common look and feel for all webpages. However, from the point of view of crawlers and indexers, templates are an important problem, because templates usually contain irrelevant information such as advertisements, menus, and banners. Processing and storing this information is likely to lead to a waste of resources (storage space, bandwidth, etc.. It has been measured that templates represent between 40% and 50% of data on the Web. Therefore, identifying templates is essential for indexing tasks. In this work we propose a novel method for automatic template extraction that is based on similarity analysis between the DOM trees of a collection of webpages that are detected using menus information. Our implementation and experiments demonstrate the usefulness of the technique.

  16. Formation and helicity control of ssDNA templated porphyrin nanoassemblies.

    Science.gov (United States)

    Sargsyan, Gevorg; Schatz, Alexandra A; Kubelka, Jan; Balaz, Milan

    2013-02-01

    We report the formation of left- (M-helix) and right-handed (P-helix) nanoassemblies of a porphyrin-diaminopurine conjugate (Por-DAP) templated by a single stranded oligodeoxythymidine (dT40) via directional hydrogen bonding. The supramolecular helicity can be controlled by the ionic strength, Por-DAP : dT40 ratio, and annealing rate.

  17. Roles of iron in light-induced transformations of dissolved organic matter

    Science.gov (United States)

    Sulzberger, B.; Durisch-Kaiser, E.

    2009-04-01

    Light-induced transformations of dissolved organic matter (DOM) play an important role with regard to DOM optical properties and bioavailability and thus carbon cycling. There exist several pathways of DOM phototransformations, depending on DOM chemical composition and on environmental factors such as the presence of iron. In iron-abundant aquatic systems, light-induced transformations of DOM may proceed via photolysis of Fe(III)-DOM complexes and/or via attack by hydroxyl radicals (OH) that are formed in the Fenton reaction (oxidation of Fe(II) by hydrogen peroxide), in addition to direct phototransformation of colored dissolved organic matter (CDOM), which is part of DOM. This paper will present results from laboratory studies with model systems and natural water samples, combined with mathematical kinetic modeling, that demonstrate the importance of photolysis of Fe(III)-DOM complexes, both in solution and at the surface of Fe(III) (hydr)oxides, in overall DOM phototransformations in the presence of iron. Photochemical studies with high-molecular-weight (HMW) and low-molecular-weight (LMW) DOM fractions from both freshwater and marine systems further indicate that LMW compounds are more reactive towards light-induced Fe(II) formation than HMW compounds. This higher reactivity of LMW materials in photochemical reduction of Fe(III) may be rationalized by more efficient photolysis of Fe(III) complexes with LMW ligands, as compared to HMW ligands, possibly due to a higher content of carboxyl functional groups contained in aquatic LMW DOM. Results from a bioavailability study with various DOM fractions from the River Tagliamento, a semi-natural, iron-abundant river in Italy, revealed that photochemical transformations drastically decreased the bioavailability of initially bioreactive LMW compounds, while that of HMW compounds did not change. These findings may be due to the higher photoreactivity of LMW compounds in the presence of iron, as indicated by a higher net

  18. Light-induced space-charge fields for the structuration of dielectric materials; Lichtinduzierte Raumladungsfelder zur Strukturierung dielektrischer Materialien

    Energy Technology Data Exchange (ETDEWEB)

    Eggert, H.A.

    2006-11-15

    Light-induced space-charge fields in lithium-niobate crystals are used for patterning of dielectric materials. This includes tailored ferroelectric domains in the bulk of the crystal, different sorts of micro and nanoparticles on a crystal surface, as well as poling of electrooptic chromophores. A stochastical model is introduced, which can describe the spatial inhomogeneous domain inversion. (orig.)

  19. SIMULATION OF THE LIGHT-INDUCED OSCILLATIONS OF THE MEMBRANE-POTENTIAL IN POTAMOGETON LEAF-CELLS

    NARCIS (Netherlands)

    MIEDEMA, H; PRINS, HBA

    1993-01-01

    An attempt has been made to simulate the light-induced oscillations of the membrane potential of Potamogeton lucens leaf cells in relation to the apoplastic pH changes. Previously it was demonstrated that the membrane potential of these cells can be described in terms of proton movements only. It is

  20. Photoinduced charge carriers in conjugated polymer-fullerene composites studied with light-induced electron-spin resonance

    NARCIS (Netherlands)

    Dyakonov, V.; Zoriniants, G.; Scharber, M.C.; Brabec, C.J.; Janssen, R.A.J.; Hummelen, J.C.

    1999-01-01

    Detailed studies on photoinduced spins in conjugated polymer/fullerene composites using (cw) light-induced electron-spin-resonance (LESR) technique are reported. Two overlapping LESR lines are observed, from positive polarons on the polymer chains and negative charges on the fullerene moieties. Micr

  1. Photoinduced charge carriers in conjugated polymer–fullerene composites studied with light-induced electron-spin resonance

    NARCIS (Netherlands)

    Dyakonov, V.; Zoriniants, G.; Scharber, M.; Brabec, C.J.; Janssen, R.A.J.; Hummelen, J.C.; Sariciftci, N.S.

    1999-01-01

    Detailed studies on photoinduced spins in conjugated polymer/fullerene composites using (cw) light-induced electron-spin-resonance (LESR) technique are reported. Two overlapping LESR lines are observed, from positive polarons on the polymer chains and negative charges on the fullerene moieties. Micr

  2. Direct characterization of ultraviolet-light-induced refractive index structures by scanning near-field optical microscopy

    DEFF Research Database (Denmark)

    Svalgaard, Mikael; Madsen, S.; Hvam, Jørn Märcher;

    1998-01-01

    We have applied a reflection scanning near-field optical microscope to directly probe ultraviolet (UV)-light-induced refractive index structures in planar glass samples. This technique permits direct comparison between topography and refractive index changes (10(-5)-10(-3)) with submicrometer...

  3. Correlating in Vitro and in Vivo Activities of Light-Inducible Dimers: A Cellular Optogenetics Guide.

    Science.gov (United States)

    Hallett, Ryan A; Zimmerman, Seth P; Yumerefendi, Hayretin; Bear, James E; Kuhlman, Brian

    2016-01-15

    Light-inducible dimers are powerful tools for cellular optogenetics, as they can be used to control the localization and activity of proteins with high spatial and temporal resolution. Despite the generality of the approach, application of light-inducible dimers is not always straightforward, as it is frequently necessary to test alternative dimer systems and fusion strategies before the desired biological activity is achieved. This process is further hindered by an incomplete understanding of the biophysical/biochemical mechanisms by which available dimers behave and how this correlates to in vivo function. To better inform the engineering process, we examined the biophysical and biochemical properties of three blue-light-inducible dimer variants (cryptochrome2 (CRY2)/CIB1, iLID/SspB, and LOVpep/ePDZb) and correlated these characteristics to in vivo colocalization and functional assays. We find that the switches vary dramatically in their dark and lit state binding affinities and that these affinities correlate with activity changes in a variety of in vivo assays, including transcription control, intracellular localization studies, and control of GTPase signaling. Additionally, for CRY2, we observe that light-induced changes in homo-oligomerization can have significant effects on activity that are sensitive to alternative fusion strategies.

  4. Template electrodeposition of catalytic nanomotors.

    Science.gov (United States)

    Wang, Joseph

    2013-01-01

    The combination of nanomaterials with electrode materials has opened new horizons in electroanalytical chemistry, and in electrochemistry in general. Over the past two decades we have witnessed an enormous activity aimed at designing new electrochemical devices based on nanoparticles, nanotubes or nanowires, and towards the use of electrochemical routes--particularly template-assisted electrodeposition--for preparing nanostructured materials. The power of template-assisted electrochemical synthesis is demonstrated in this article towards the preparation and the realization of self-propelled catalytic nanomotors, ranging from Pt-Au nanowire motors to polymer/Pt microtube engines. Design considerations affecting the propulsion behavior of such catalytic nanomotors are discussed along with recent bioanalytical and environmental applications. Despite recent major advances, artificial nanomotors have a low efficiency compared to their natural counterparts. Hopefully, the present Faraday Discussion will stimulate other electrochemistry teams to contribute to the fascinating area of artificial nanomachines.

  5. LTL - The Little Template Library

    Science.gov (United States)

    Gössl, C. A.; Drory, N.; Snigula, J.

    2004-07-01

    The Little Template Library is an expression templates based C++ library for array processing, image processing, FITS and ASCII I/O, and linear algebra. It is released under the GNU Public License (GPL). Although the library is developed with application to astronomical image and data processing in mind, it is by no means restricted to these fields of application. In fact, it qualifies as a fully general array processing package. Focus is laid on a high abstraction level regarding the handling of expressions involving arrays or parts thereof and linear algebra related operations without the usually involved negative impact on performance. The price to pay is dependence on a compiler implementing enough of the current ANSI C++ specification, as well as significantly higher demand on resources at compile time. The LTL provides dynamic arrays of up to 5 dimensions, sub-arrays and slicing, support for fixed size vectors and matrices including basic linear algebra operations, expression templates based evaluation, and I/O facilities for columnar ASCII and FITS format files. In addition it supplies utility classes for statistics, linear and non-linear least squares fitting, and command line and configuration file parsing. YODA (Drory 2002) and all elements of the WeCAPP reduction pipeline (Riffeser et al. 2001, Gössl & Riffeser 2002, 2003) were implemented using the LTL.

  6. Testing sensory evidence against mnemonic templates.

    Science.gov (United States)

    Myers, Nicholas E; Rohenkohl, Gustavo; Wyart, Valentin; Woolrich, Mark W; Nobre, Anna C; Stokes, Mark G

    2015-01-01

    Most perceptual decisions require comparisons between current input and an internal template. Classic studies propose that templates are encoded in sustained activity of sensory neurons. However, stimulus encoding is itself dynamic, tracing a complex trajectory through activity space. Which part of this trajectory is pre-activated to reflect the template? Here we recorded magneto- and electroencephalography during a visual target-detection task, and used pattern analyses to decode template, stimulus, and decision-variable representation. Our findings ran counter to the dominant model of sustained pre-activation. Instead, template information emerged transiently around stimulus onset and quickly subsided. Cross-generalization between stimulus and template coding, indicating a shared neural representation, occurred only briefly. Our results are compatible with the proposal that template representation relies on a matched filter, transforming input into task-appropriate output. This proposal was consistent with a signed difference response at the perceptual decision stage, which can be explained by a simple neural model.

  7. Characterization of Phototransduction Gene Knockouts Revealed Important Signaling Networks in the Light-Induced Retinal Degeneration

    Directory of Open Access Journals (Sweden)

    Jayalakshmi Krishnan

    2008-01-01

    Full Text Available Understanding the molecular pathways mediating neuronal function in retinas can be greatly facilitated by the identification of genes regulated in the retinas of different mutants under various light conditions. We attempted to conduct a gene chip analysis study on the genes regulated during rhodopsin kinase (Rhok-/- and arrestin (Sag-/- knockout and double knockouts in mice retina. Hence, mice were exposed to constant illumination of 450 lux or 6,000 lux on dilated pupils for indicated periods. The retinas were removed after the exposure and processed for microarray analysis. Double knockout was associated with immense changes in gene expression regulating a number of apoptosis inducing transcription factors. Subsequently, network analysis revealed that during early exposure the transcription factors, p53, c-MYC, c-FOS, JUN, and, in late phase, NF-B, appeared to be essential for the initiation of light-induced retinal rod loss, and some other classical pro- and antipoptotic genes appeared to be significantly important as well.

  8. Iterative experiment design guides the characterization of a light-inducible gene expression circuit.

    Science.gov (United States)

    Ruess, Jakob; Parise, Francesca; Milias-Argeitis, Andreas; Khammash, Mustafa; Lygeros, John

    2015-06-30

    Systems biology rests on the idea that biological complexity can be better unraveled through the interplay of modeling and experimentation. However, the success of this approach depends critically on the informativeness of the chosen experiments, which is usually unknown a priori. Here, we propose a systematic scheme based on iterations of optimal experiment design, flow cytometry experiments, and Bayesian parameter inference to guide the discovery process in the case of stochastic biochemical reaction networks. To illustrate the benefit of our methodology, we apply it to the characterization of an engineered light-inducible gene expression circuit in yeast and compare the performance of the resulting model with models identified from nonoptimal experiments. In particular, we compare the parameter posterior distributions and the precision to which the outcome of future experiments can be predicted. Moreover, we illustrate how the identified stochastic model can be used to determine light induction patterns that make either the average amount of protein or the variability in a population of cells follow a desired profile. Our results show that optimal experiment design allows one to derive models that are accurate enough to precisely predict and regulate the protein expression in heterogeneous cell populations over extended periods of time.

  9. LSD1 and HY5 Antagonistically Regulate Red Light induced-Programmed Cell Death in Arabidopsis

    Directory of Open Access Journals (Sweden)

    Tingting eChai

    2015-05-01

    Full Text Available Programmed cell death (PCD in plant is triggered by abiotic and biotic stress. Light-dependent PCD is unique to plants. Light-induced PCD also requires reactive oxygen species (ROS and salicylic acid (SA. In this study, lesion simulating disease1 (LSD1 and elongated hypocotyl 5 (HY5 perform opposite roles to regulate excess red light (RL-triggered PCD associated with ROS and SA production. Under RL, the lsd1 mutant released more ROS and SA and displayed a stronger cell death rate than the hy5 mutant. It was shown that active LSD1 converted into inactive form by changing the redox status of the plastoquinone pool, and HY5 interacted with phytochrome B (phyB to promote PCD in response to RL. LSD1 inhibited the enhanced disease susceptibility 1 (EDS1 expression by upregulating SR1, whereas HY5 enhanced the enhanced EDS1 expression by binding to the G-box of the EDS1 promoter. This study suggested that LSD1 and HY5 antagonistically modulated EDS1-dependent ROS and SA signaling; thus, PCD was mediated in response to RL.

  10. LSD1 and HY5 antagonistically regulate red light induced-programmed cell death in Arabidopsis.

    Science.gov (United States)

    Chai, Tingting; Zhou, Jun; Liu, Jian; Xing, Da

    2015-01-01

    Programmed cell death (PCD) in plant is triggered by abiotic and biotic stress. Light-dependent PCD is unique to plants. Light-induced PCD also requires reactive oxygen species (ROS) and salicylic acid (SA). In this study, lesion simulating disease1 (LSD1) and elongated hypocotyl 5 (HY5) perform opposite roles to regulate excess red light (RL)-triggered PCD associated with ROS and SA production. Under RL, the lsd1 mutant released more ROS and SA and displayed a stronger cell death rate than the hy5 mutant. It was shown that active LSD1 converted into inactive form by changing the redox status of the plastoquinone pool, and HY5 interacted with phytochrome B (phyB) to promote PCD in response to RL. LSD1 inhibited the enhanced disease susceptibility 1 (EDS1) expression by upregulating SR1, whereas HY5 enhanced the enhanced EDS1 expression by binding to the G-box of the EDS1 promoter. This study suggested that LSD1 and HY5 antagonistically modulated EDS1-dependent ROS and SA signaling; thus, PCD was mediated in response to RL.

  11. Light-induced oxidative stress, N-formylkynurenine, and oxygenic photosynthesis.

    Directory of Open Access Journals (Sweden)

    Tina M Dreaden Kasson

    Full Text Available Light stress in plants results in damage to the water oxidizing reaction center, photosystem II (PSII. Redox signaling, through oxidative modification of amino acid side chains, has been proposed to participate in this process, but the oxidative signals have not yet been identified. Previously, we described an oxidative modification, N-formylkynurenine (NFK, of W365 in the CP43 subunit. The yield of this modification increases under light stress conditions, in parallel with the decrease in oxygen evolving activity. In this work, we show that this modification, NFK365-CP43, is present in thylakoid membranes and may be formed by reactive oxygen species produced at the Mn(4CaO(5 cluster in the oxygen-evolving complex. NFK accumulation correlates with the extent of photoinhibition in PSII and thylakoid membranes. A modest increase in ionic strength inhibits NFK365-CP43 formation, and leads to accumulation of a new, light-induced NFK modification (NFK317 in the D1 polypeptide. Western analysis shows that D1 degradation and oligomerization occur under both sets of conditions. The NFK modifications in CP43 and D1 are found 17 and 14 Angstrom from the Mn(4CaO(5 cluster, respectively. Based on these results, we propose that NFK is an oxidative modification that signals for damage and repair in PSII. The data suggest a two pathway model for light stress responses. These pathways involve differential, specific, oxidative modification of the CP43 or D1 polypeptides.

  12. Multiwalled Carbon Nanotube-TiO2 Nanocomposite for Visible-Light-Induced Photocatalytic Hydrogen Evolution

    Directory of Open Access Journals (Sweden)

    Ke Dai

    2014-01-01

    Full Text Available Multiwalled carbon nanotube- (MWCNT- TiO2 nanocomposite was synthesized via hydrothermal process and characterized by X-ray diffraction, UV-vis diffuse reflectance spectroscopy, field emission scanning electron microscope, thermogravimetry analysis, and N2 adsorption-desorption isotherms. Appropriate pretreatment on MWCNTs could generate oxygen-containing groups, which is beneficial for forming intimate contact between MWCNTs and TiO2 and leads to a higher thermal stability of MWCNT-TiO2 nanocomposite. Modification with MWCNTs can extend the visible-light absorption of TiO2. 5 wt% MWCNT-TiO2 derived from hydrothermal treatment at 140°C exhibiting the highest hydrogen generation rate of 15.1 μmol·h−1 under visible-light irradiation and a wide photoresponse range from 350 to 475 nm with moderate quantum efficiency (4.4% at 420 nm and 3.7% at 475 nm. The above experimental results indicate that the MWCNT-TiO2 nanocomposite is a promising photocatalyst with good stability and visible-light-induced photoactivity.

  13. Light-induced negative differential resistance in graphene/Si-quantum-dot tunneling diodes.

    Science.gov (United States)

    Lee, Kyeong Won; Jang, Chan Wook; Shin, Dong Hee; Kim, Jong Min; Kang, Soo Seok; Lee, Dae Hun; Kim, Sung; Choi, Suk-Ho; Hwang, Euyheon

    2016-01-01

    One of the interesing tunneling phenomena is negative differential resistance (NDR), the basic principle of resonant-tunneling diodes. NDR has been utilized in various semiconductor devices such as frequency multipliers, oscillators, relfection amplifiers, logic switches, and memories. The NDR in graphene has been also reported theoretically as well as experimentally, but should be further studied to fully understand its mechanism, useful for practical device applications. Especially, there has been no observation about light-induced NDR (LNDR) in graphene-related structures despite very few reports on the LNDR in GaAs-based heterostructures. Here, we report first observation of LNDR in graphene/Si quantum dots-embedded SiO2 (SQDs:SiO2) multilayers (MLs) tunneling diodes. The LNDR strongly depends on temperature (T) as well as on SQD size, and the T dependence is consistent with photocurrent (PC)-decay behaviors. With increasing light power, the PC-voltage curves are more structured with peak-to-valley ratios over 2 at room temperature. The physical mechanism of the LNDR, governed by resonant tunneling of charge carriers through the minibands formed across the graphene/SQDs:SiO2 MLs and by their nonresonant phonon-assisted tunneling, is discussed based on theoretical considerations.

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

    Science.gov (United States)

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

    2010-05-31

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

  15. Effect of magnesium doping on the light-induced hydrophilicity of ZnO thin films

    Institute of Scientific and Technical Information of China (English)

    Huang Kai; Lü Jianguo; Zhang Li; Tang Zhen; Yu Jiangying; Li Ping; Liu Feng

    2012-01-01

    Undoped and Mg-doped ZnO thin films were deposited on Si (111) and quartz substrates by using the sol-gel method.Microstructure,surface topography and water contact angle of the thin films have been measured by X-ray diffraction (XRD),an atomic force microscope (AFM) and water contact angle apparatus,respectively.The XRD results show that all the thin films are polycrystalline with a hexagonal structure and have a preferred orientation along the c-axis perpendicular to the substrate.With the increase of Mg concentration,the RMS roughness increases from 2.14 to 9.56 nm and the contact angle of the un-irradiated thin films decreases from 89° to 82°.The wetting behavior of the resulting films can be reversibly switched from hydrophobic to hydrophilic,through alternation of UV illumination and dark storage.The light-induced efficiency of the thin films increases with the increase of Mg concentration.

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

    Science.gov (United States)

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

    2006-09-01

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

  17. Phytochrome and retrograde signalling pathways converge to antagonistically regulate a light-induced transcriptional network.

    Science.gov (United States)

    Martín, Guiomar; Leivar, Pablo; Ludevid, Dolores; Tepperman, James M; Quail, Peter H; Monte, Elena

    2016-05-06

    Plastid-to-nucleus retrograde signals emitted by dysfunctional chloroplasts impact photomorphogenic development, but the molecular link between retrograde- and photosensory-receptor signalling has remained unclear. Here, we show that the phytochrome and retrograde signalling (RS) pathways converge antagonistically to regulate the expression of the nuclear-encoded transcription factor GLK1, a key regulator of a light-induced transcriptional network central to photomorphogenesis. GLK1 gene transcription is directly repressed by PHYTOCHROME-INTERACTING FACTOR (PIF)-class bHLH transcription factors in darkness, but light-activated phytochrome reverses this activity, thereby inducing expression. Conversely, we show that retrograde signals repress this induction by a mechanism independent of PIF mediation. Collectively, our data indicate that light at moderate levels acts through the plant's nuclear-localized sensory-photoreceptor system to induce appropriate photomorphogenic development, but at excessive levels, sensed through the separate plastid-localized RS system, acts to suppress such development, thus providing a mechanism for protection against photo-oxidative damage by minimizing the tissue exposure to deleterious radiation.

  18. Visible Light Induces Melanogenesis in Human Skin through a Photoadaptive Response

    Science.gov (United States)

    Randhawa, Manpreet; Seo, InSeok; Liebel, Frank; Southall, Michael D.; Kollias, Nikiforos; Ruvolo, Eduardo

    2015-01-01

    Visible light (400–700 nm) lies outside of the spectral range of what photobiologists define as deleterious radiation and as a result few studies have studied the effects of visible light range of wavelengths on skin. This oversight is important considering that during outdoors activities skin is exposed to the full solar spectrum, including visible light, and to multiple exposures at different times and doses. Although the contribution of the UV component of sunlight to skin damage has been established, few studies have examined the effects of non-UV solar radiation on skin physiology in terms of inflammation, and limited information is available regarding the role of visible light on pigmentation. The purpose of this study was to determine the effect of visible light on the pro-pigmentation pathways and melanin formation in skin. Exposure to visible light in ex-vivo and clinical studies demonstrated an induction of pigmentation in skin by visible light. Results showed that a single exposure to visible light induced very little pigmentation whereas multiple exposures with visible light resulted in darker and sustained pigmentation. These findings have potential implications on the management of photo-aggravated pigmentary disorders, the proper use of sunscreens, and the treatment of depigmented lesions. PMID:26121474

  19. Trapped-ion probing of light-induced charging effects on dielectrics

    Energy Technology Data Exchange (ETDEWEB)

    Harlander, M; Brownnutt, M; Haensel, W; Blatt, R, E-mail: max.harlander@uibk.ac.a [Institut fuer Experimentalphysik, Universitaet Innsbruck, Technikerstrasse 25, A-6020 Innsbruck (Austria)

    2010-09-15

    We use a string of confined {sup 40}Ca{sup +} ions to measure perturbations to a trapping potential which are caused by the light-induced charging of an antireflection-coated window and of insulating patches on the ion-trap electrodes. The electric fields induced at the ions' position are characterized as a function of distance to the dielectric and as a function of the incident optical power and wavelength. The measurement of the ion-string position is sensitive to as few as 40 elementary charges per {radical}(Hz) on the dielectric at distances of the order of millimetres, and perturbations are observed for illuminations with light of wavelengths as large as 729 nm. This has important implications for the future of miniaturized ion-trap experiments, notably with regard to the choice of electrode material and the optics that must be integrated in the vicinity of the ion. The method presented here can be readily applied to the investigation of charging effects beyond the context of ion-trap experiments.

  20. Analysis of light-induced transmembrane ion gradients and membrane potential in Photosystem I proteoliposomes.

    Science.gov (United States)

    Pennisi, Cristian Pablo; Greenbaum, Elias; Yoshida, Ken

    2010-01-01

    Photosystem I (PSI) complexes can support a light-driven electrochemical gradient for protons, which is the driving force for energy-conserving reactions across biological membranes. In this work, a computational model that enables a quantitative description of the light-induced proton gradients across the membrane of PSI proteoliposomes is presented. Using a set of electrodiffusion equations, a compartmental model of a vesicle suspended in aqueous medium was studied. The light-mediated proton movement was modeled as a single proton pumping step with backpressure of the electric potential. The model fits determinations of pH obtained from PSI proteoliposomes illuminated in the presence of mediators of cyclic electron transport. The model also allows analysis of the proton gradients in relation to the transmembrane ion fluxes and electric potential. Sensitivity analysis enabled a determination of the parameters that have greater influence on steady-state levels and onset/decay rates of transmembrane pH and electric potential. This model could be used as a tool for optimizing PSI proteoliposomes for photo-electrochemical applications.

  1. Analysis of Light-Induced Transmembrane Ion Gradients and Membrane Potential in Photosystem I Proteoliposomes

    Energy Technology Data Exchange (ETDEWEB)

    Pennisi, Cristian P. [Aalborg University, Aalborg, Denmark; Greenbaum, Elias [ORNL; Yoshida, Ken [Aalborg University, Aalborg, Denmark

    2010-01-01

    Photosystem I (PSI) complexes can support a light-driven electrochemical gradient for protons, which is the driving force for energy-conserving reactions across biological membranes. In this work, a computational model that enables a quantitative description of the light-induced proton gradients across the membrane of PSI proteoliposomes is presented. Using a set of electrodiffusion equations, a compartmental model of a vesicle suspended in aqueous medium was studied. The light-mediated proton movement was modeled as a single proton pumping step with backpressure of the electric potential. The model fits determinations of pH obtained from PSI proteoliposomes illuminated in the presence of mediators of cyclic electron transport. The model also allows analysis of the proton gradients in relation to the transmembrane ion fluxes and electric potential. Sensitivity analysis enabled a determination of the parameters that have greater influence on steady-state levels and onset/decay rates of transmembrane pH and electric potential. This model could be used as a tool for optimizing PSI proteoliposomes for photo-electrochemical applications.

  2. Light-induced hetero-Diels-Alder cycloaddition: a facile and selective photoclick reaction.

    Science.gov (United States)

    Arumugam, Selvanathan; Popik, Vladimir V

    2011-04-13

    2-Napthoquinone-3-methides (oNQMs) generated by efficient photodehydration (Φ=0.2) of 3-(hydroxymethyl)-2-naphthol undergo facile hetero-Diels-Alder addition (k(D-A)∼ 4×10(4) M(-1) s(-1)) to electron-rich polarized olefins in an aqueous solution. The resulting photostable benzo[g]chromans are produced in high to quantitative yield. The unreacted oNQM is rapidly hydrated (k(H2O) ∼145 s(-1)) to regenerate the starting diol. This competition between hydration and cycloaddition makes oNQMs highly selective, since only vinyl ethers and enamines are reactive enough to form the Diels-Alder adduct in an aqueous solution; no cycloaddition was observed with other types of alkenes. To achieve photolabeling or photoligation of two substrates, one is derivatized with a vinyl ether moiety, while 3-(hydroxymethyl)-2-naphthol is attached to the other via an appropriate linker. The light-induced Diels-Alder "click" strategy permits the formation of either a permanent or hydrolytically labile linkage. Rapid kinetics of this photoclick reaction (k=4×10(4) M(-1) s(-1)) is useful for time-resolved applications. The short lifetime (τ ∼7 ms in H(2)O) of the active form of the photoclick reagent prevents its migration from the site of irradiation, thus, allowing for spatial control of the ligation or labeling.

  3. Towards controlling the dissociation probability by light-induced conical intersections

    CERN Document Server

    Csehi, András; Cederbaum, Lorenz S; Vibók, Ágnes

    2016-01-01

    Light-induced conical intersections (LICIs) can be formed both by standing or by running laser waves. The position of a LICI is determined by the laser frequency while the laser intensity controls the strength of the nonadiabatic coupling. Recently, it was shown within the LICI framework that linearly chirped laser pulses have an impact on the dissociation dynamics of the $D_{2}^{+}$ molecule (J. Chem. Phys. 143, 014305, (2015); ibid 144, 074309, (2016)). In this work we exploit this finding and perform calculations using chirped laser pulses in which the time dependence of the laser frequency is designed so as to force the LICI to move together with the field-free vibrational wave packet as much as possible. Since nonadiabaticity is strongest in the vicinity of the conical intersection, this is the first step towards controlling the dissociation process via the LICI. Our showcase example is again the $D_{2}^{+}$ molecular ion. To demonstrate the impact of the LICIs on the dynamical properties of diatomics, t...

  4. A remotely driven and controlled micro-gripper fabricated from light-induced deformation smart material

    Science.gov (United States)

    Huang, Chaolei; Lv, Jiu-an; Tian, Xiaojun; Wang, Yuechao; Liu, Jie; Yu, Yanlei

    2016-09-01

    Micro-gripper is an important tool to manipulate and assemble micro-scale objects. Generally, as micro-gripper is too small to be directly driven by general motors, it always needs special driving devices and suitable structure design. In this paper, two-finger micro-grippers are designed and fabricated, which utilize light-induced deformation smart material to make one of the two fingers. As the smart material is directly driven and controlled by remote lights instead of lines and motors, this light-driven mode simplifies the design of the two-finger micro-gripper and avoids special drivers and complex mechanical structure. In addition, a micro-manipulation experiment system is set up which is based on the light-driven micro-gripper. Experimental results show that this remotely light-driven micro-gripper has ability to manipulate and assemble micro-scale objects both in air and water. Furthermore, two micro-grippers can also work together for cooperation which can further enhance the assembly ability. On the other hand, this kind of remotely controllable micro-gripper that does not require on-board energy storage, can be used in mobile micro-robot as a manipulation hand.

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

    Science.gov (United States)

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

    2013-11-01

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

  6. Light-induced degradation in compensated p- and n-type Czochralski silicon wafers

    Science.gov (United States)

    Geilker, Juliane; Kwapil, Wolfram; Rein, Stefan

    2011-03-01

    Light-induced degradation (LID) due to boron-oxygen complex formation seriously diminishes the minority carrier lifetime of p-type Czochralski-grown (Cz) wafers. Depending linearly on the boron concentration NA in uncompensated silicon, the boron-oxygen defect density was suggested to depend on the net doping concentration p0 = NA - ND in compensated p-type samples, containing similar amounts of boron and phosphorus [D. Macdonald, F. Rougieux, A. Cuevas, et al., Journal of Applied Physics 105, 093704 (2009)]. However, this dependency contradicts observations of LID in compensated n-type silicon wafers [T. Schutz-Kuchly, J. Veirman, S. Dubois, et al., Applied Physics Letters 96, 1 (2010)], which are confirmed in this study by investigating the boron-oxygen complex formation on a large variety of compensated p- and n-type samples. In spite of their high boron content, compensated n-type samples may show a less pronounced LID than p-type samples containing less boron. Our experiments indicate that in compensated silicon, the defect concentration is only a function of the compensation ratio RC = (NA + ND)/(NA - ND).

  7. Light-induced negative differential resistance in graphene/Si-quantum-dot tunneling diodes

    Science.gov (United States)

    Lee, Kyeong Won; Jang, Chan Wook; Shin, Dong Hee; Kim, Jong Min; Kang, Soo Seok; Lee, Dae Hun; Kim, Sung; Choi, Suk-Ho; Hwang, Euyheon

    2016-07-01

    One of the interesing tunneling phenomena is negative differential resistance (NDR), the basic principle of resonant-tunneling diodes. NDR has been utilized in various semiconductor devices such as frequency multipliers, oscillators, relfection amplifiers, logic switches, and memories. The NDR in graphene has been also reported theoretically as well as experimentally, but should be further studied to fully understand its mechanism, useful for practical device applications. Especially, there has been no observation about light-induced NDR (LNDR) in graphene-related structures despite very few reports on the LNDR in GaAs-based heterostructures. Here, we report first observation of LNDR in graphene/Si quantum dots-embedded SiO2 (SQDs:SiO2) multilayers (MLs) tunneling diodes. The LNDR strongly depends on temperature (T) as well as on SQD size, and the T dependence is consistent with photocurrent (PC)-decay behaviors. With increasing light power, the PC-voltage curves are more structured with peak-to-valley ratios over 2 at room temperature. The physical mechanism of the LNDR, governed by resonant tunneling of charge carriers through the minibands formed across the graphene/SQDs:SiO2 MLs and by their nonresonant phonon-assisted tunneling, is discussed based on theoretical considerations.

  8. Quantification of Canine Dental Plaque Using Quantitative Light-Induced Fluorescence.

    Science.gov (United States)

    Wallis, Corrin; Gill, Yadvinder; Colyer, Alison; Davis, Ian; Allsopp, Judi; Komarov, Gleb; Higham, Susan; Harris, Stephen

    2016-03-01

    The aim of this work was to evaluate Quantitative Light-induced Fluorescence (QLF) as an alternative to the established Logan and Boyce method for determining plaque coverage of dogs' teeth. In a series of studies in conscious and anesthetized dogs, QLF showed good intra-photographer repeatability (coefficient of variation [CV] of 7.5% for undisclosed teeth) and inter-photographer reproducibility (CV of 3.2% for undisclosed teeth and 8.5% for disclosed teeth). The QLF software accurately identifies areas of plaque as demonstrated by comparison to the variability of 5 human scorers, manually marking plaque on QLF-acquired images (P = 0.1). There was good agreement with the modified Logan and Boyce method in the percentage reduction in plaque accumulation measured when dogs were fed an oral care chew versus no chew. To see a 15% difference in plaque accumulation, which is considered sufficient by the Veterinary Oral Health Council to differentiate between 2 treatments, a retrospective power analysis (90%) of the data established that only 7 dogs would be required, compared to 19 dogs for the modified Logan and Boyce method. QLF is a reliable method for measuring dental plaque in dogs with the added advantage that it is not subjective and requires fewer animals.

  9. Blue-light-induced rapid chloroplast de-anchoring in Vallisneria epidermal cells

    Institute of Scientific and Technical Information of China (English)

    Yuuki Sakai; Shin-Ichiro Inoue; Akiko Harada; Ken-Ichiro Shimazaki; Shingo Takagi

    2015-01-01

    In the outer periclinal cytoplasm of leaf epidermal cells of an aquatic angiosperm Vallisneria, blue light induces “chloroplast de‐anchoring”, a rapid decline in the resistance of chloroplasts against centrifugal force. Chloroplast deanchoring is known induced within 1 min of irradiation with high‐fluence‐rate blue light specifically, preceding the commencement of chloroplasts migration toward the anticlinal cytoplasm. However, its regulatory mechanism has remained elusive, although pharmacological analysis suggested that a calcium release from intracellular calcium stores is necessary for the response. In search of the responsible photoreceptors, immunoblotting analysis using antibodies against phototropins demonstrated that cross‐reactive polypeptides of 120‐kDa exist in the plasma‐membrane fraction prepared from the leaves. In vitro phosphorylation analysis revealed that 120‐kDa polypeptides were phosphorylated by exposure to blue light in a fluence‐dependent manner. The blue‐light‐induced phosphorylation activity was sensitive to a Ser/Thr kinase inhibitor, staurosporine, and unusually was retained at a high level for a long time in darkness. Furthermore, phototropin gene homologs (Vallisneria PHOTOTROPIN1 and PHOTOTROPIN2) expressed in leaves were isolated. We propose that calciumregulated chloroplast de‐anchoring, possibly mediated by phototropins, is an initial process of the blue‐light‐induced avoidance response of chloroplasts in Vallisneria.

  10. Light-induced fading of the PSL signal from irradiated herbs and spices

    Science.gov (United States)

    Alberti, A.; Corda, U.; Fuochi, P.; Bortolin, E.; Calicchia, A.; Onori, S.

    2007-08-01

    Reliability of the photo-stimulated luminescence (PSL) technique, as screening method for irradiated food identification, has been tested with three kinds of herbs and spices (oregano, red pepper and fennel), prepared in two different ways (granular: i.e. seeds and flakes, or powdered), over a long period of storage with different light exposures. The irradiated samples kept in the dark gave always a positive response (the sample is correctly classified as "irradiated") for the overall examination period. The samples kept under ambient light conditions, in typical commercial glass containers, exhibited a reduction of the PSL signal, more or less pronounced depending on the type of food and packaging. The different PSL response of the irradiated samples is to be related to the quantity and quality of the mineral debris present in the individual food. It was also found that, for the same type of food, the light-induced fading was much stronger for the flaked and seed samples than for the corresponding powder samples, the penetrating capability of light being much more inhibited in powdered than in whole seeds or flaked form samples. The observed light bleaching of the PSL signal in irradiated herbs and spices is of practical relevance since it may lead to false negative classifications.

  11. A visible light-induced photocatalytic silver enhancement reaction for gravimetric biosensors.

    Science.gov (United States)

    Ko, Wooree; Yim, Changyong; Jung, Namchul; Joo, Jinmyoung; Jeon, Sangmin; Seo, Hyejung; Lee, Soo Suk; Park, Jae Chan

    2011-10-07

    We have developed a novel microgravimetric immunosensor using a WO(3) nanoparticle-modified immunoassay and a silver enhancement reaction. When the nanoparticles in silver ion solution (i.e.  AgNO(3)) are exposed to visible light, the silver ions are photocatalytically reduced and form a metallic silver coating on the nanoparticles. This silver coating consequently induces changes in the mass and light absorption spectrum. Although photocatalytic reduction reactions can be achieved using ultraviolet (UV) light and TiO(2) nanoparticles as described in our previous publication (Seo et al 2010 Nanotechnology 21 505502), the use of UV light in biosensing applications has drawbacks in that UV light can damage proteins. In addition, conventional quartz crystal substrates must be passivated to prevent undesirable silver ion reduction on their gold-coated sensing surfaces. We addressed these problems by adopting a visible light-induced photocatalytic silver enhancement method using WO(3) nanoparticles and lateral field excited (LFE) quartz crystals. As a proof-of-concept demonstration of the technique, streptavidin was adsorbed onto an LFE quartz crystal, and its mass was enhanced with biotinylated WO(3) nanoparticles, this being followed by a photocatalytic silver enhancement reaction. The mass change due to the enhancement was found to be > 30 times greater than the mass change obtained with the streptavidin alone.

  12. Submillimetre Network Formation by Light-induced Hybridization of Zeptomole-level DNA

    Science.gov (United States)

    Iida, Takuya; Nishimura, Yushi; Tamura, Mamoru; Nishida, Keisuke; Ito, Syoji; Tokonami, Shiho

    2016-12-01

    Macroscopic unique self-assembled structures are produced via double-stranded DNA formation (hybridization) as a specific binding essential in biological systems. However, a large amount of complementary DNA molecules are usually required to form an optically observable structure via natural hybridization, and the detection of small amounts of DNA less than femtomole requires complex and time-consuming procedures. Here, we demonstrate the laser-induced acceleration of hybridization between zeptomole-level DNA and DNA-modified nanoparticles (NPs), resulting in the assembly of a submillimetre network-like structure at the desired position with a dramatic spectral modulation within several minutes. The gradual enhancement of light-induced force and convection facilitated the two-dimensional network growth near the air-liquid interface with optical and fluidic symmetry breakdown. The simultaneous microscope observation and local spectroscopy revealed that the assembling process and spectral change are sensitive to the DNA sequence. Our findings establish innovative guiding principles for facile bottom-up production via various biomolecular recognition events.

  13. Understanding Light-Induced Degradation of c-Si Solar Cells: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Sopori, B.; Basnyat, P.; Devayajanam, S.; Shet, S.; Mehta, V.; Binns, J.; Appel, J.

    2012-06-01

    We discuss results of our investigations toward understanding bulk and surface components of light-induced degradation (LID) in low-Fe c-Si solar cells. The bulk effects, arising from boron-oxygen defects, are determined by comparing degradation of cell parameters and their thermal recovery, with that of the minority-carrier lifetime (964;) in sister wafers. We found that the recovery of 964; in wafers takes a much longer annealing time compared to that of the cell. We also show that cells having SiN:H coating experience a surface degradation (ascribed to surface recombination). The surface LID is seen as an increase in the q/2kT component of the dark saturation current (J02). The surface LID does not recover fully upon annealing and is attributed to degradation of the SiN:H-Si interface. This behavior is also exhibited by mc-Si cells that have very low oxygen content and do not show any bulk degradation.

  14. A visible light-induced photocatalytic silver enhancement reaction for gravimetric biosensors

    Energy Technology Data Exchange (ETDEWEB)

    Ko, Wooree; Yim, Changyong; Jung, Namchul; Joo, Jinmyoung; Jeon, Sangmin [Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang (Korea, Republic of); Seo, Hyejung; Lee, Soo Suk; Park, Jae Chan, E-mail: jeons@postech.ac.kr [Samsung Advanced Institute of Technology (SAIT), Suwon (Korea, Republic of)

    2011-10-07

    We have developed a novel microgravimetric immunosensor using a WO{sub 3} nanoparticle-modified immunoassay and a silver enhancement reaction. When the nanoparticles in silver ion solution (i.e. AgNO{sub 3}) are exposed to visible light, the silver ions are photocatalytically reduced and form a metallic silver coating on the nanoparticles. This silver coating consequently induces changes in the mass and light absorption spectrum. Although photocatalytic reduction reactions can be achieved using ultraviolet (UV) light and TiO{sub 2} nanoparticles as described in our previous publication (Seo et al 2010 Nanotechnology 21 505502), the use of UV light in biosensing applications has drawbacks in that UV light can damage proteins. In addition, conventional quartz crystal substrates must be passivated to prevent undesirable silver ion reduction on their gold-coated sensing surfaces. We addressed these problems by adopting a visible light-induced photocatalytic silver enhancement method using WO{sub 3} nanoparticles and lateral field excited (LFE) quartz crystals. As a proof-of-concept demonstration of the technique, streptavidin was adsorbed onto an LFE quartz crystal, and its mass was enhanced with biotinylated WO{sub 3} nanoparticles, this being followed by a photocatalytic silver enhancement reaction. The mass change due to the enhancement was found to be > 30 times greater than the mass change obtained with the streptavidin alone.

  15. Light-induced reactions of Escherichia coli DNA photolyase monitored by Fourier transform infrared spectroscopy.

    Science.gov (United States)

    Schleicher, Erik; Hessling, Benedikt; Illarionova, Viktoria; Bacher, Adelbert; Weber, Stefan; Richter, Gerald; Gerwert, Klaus

    2005-04-01

    Cyclobutane-type pyrimidine dimers generated by ultraviolet irradiation of DNA can be cleaved by DNA photolyase. The enzyme-catalysed reaction is believed to be initiated by the light-induced transfer of an electron from the anionic FADH- chromophore of the enzyme to the pyrimidine dimer. In this contribution, first infrared experiments using a novel E109A mutant of Escherichia coli DNA photolyase, which is catalytically active but unable to bind the second cofactor methenyltetrahydrofolate, are described. A stable blue-coloured form of the enzyme carrying a neutral FADH radical cofactor can be interpreted as an intermediate analogue of the light-driven DNA repair reaction and can be reduced to the enzymatically active FADH- form by red-light irradiation. Difference Fourier transform infrared (FT-IR) spectroscopy was used to monitor vibronic bands of the blue radical form and of the fully reduced FADH- form of the enzyme. Preliminary band assignments are based on experiments with 15N-labelled enzyme and on experiments with D2O as solvent. Difference FT-IR measurements were also used to observe the formation of thymidine dimers by ultraviolet irradiation and their repair by light-driven photolyase catalysis. This study provides the basis for future time-resolved FT-IR studies which are aimed at an elucidation of a detailed molecular picture of the light-driven DNA repair process.

  16. Mechanisms for light induced degradation in MAPbI3 perovskite thin films and solar cells

    Science.gov (United States)

    Abdelmageed, Ghada; Jewell, Leila; Hellier, Kaitlin; Seymour, Lydia; Luo, Binbin; Bridges, Frank; Zhang, Jin Z.; Carter, Sue

    2016-12-01

    Organometal halide perovskites are highly promising materials for photovoltaic applications, yet their rapid degradation remains a significant challenge. Here, the light-induced structural degradation mechanism of methylammonium lead iodide (MAPbI3) perovskite films and devices is studied in low humidity environment using X-Ray Diffraction, Ultraviolet-Visible (UV-Vis) absorption spectroscopy, Extended X-ray Absorption Fine Structure spectroscopy, Fourier Transform Infrared spectroscopy, and device measurements. Under dry conditions, the perovskite film degrades only in the presence of both light and oxygen, which together induce the formation of halide anions through donation of electrons to the surrounding oxygen. The halide anions generate free radicals that deprotonate the methylammonium cation and form the highly volatile CH3NH2 molecules that escape and leave pure PbI2 behind. The device findings show that changes in the local structure at the TiO2 mesoporous layer occur with light, even in the absence of oxygen, and yet such changes can be prevented by the application of UV blocking layer on the cells. Our results indicate that the stability of mp-TiO2-MAPbI3 photovoltaics can be dramatically improved with effective encapsulation that protects the device from UV light, oxygen, and moisture.

  17. Theory of light-induced resonances with collective Higgs and Leggett modes in multiband superconductors

    Science.gov (United States)

    Murotani, Yuta; Tsuji, Naoto; Aoki, Hideo

    2017-03-01

    We theoretically investigate coherent optical excitations of collective modes in two-band BCS superconductors, which accommodate two Higgs modes and one Leggett mode corresponding, respectively, to the amplitude and relative-phase oscillations of the superconducting order parameters associated with the two bands. We find, based on a mean-field analysis, that each collective mode can be resonantly excited through a nonlinear light-matter coupling when the doubled frequency of the driving field coincides with the frequency of the corresponding mode. Among the two Higgs modes, the higher-energy one exhibits a sharp resonance with light, while the lower-energy mode has a broadened resonance width. The Leggett mode is found to be resonantly induced by a homogeneous ac electric field because the leading nonlinear effect generates a potential offset between the two bands that couples to the relative phase of the order parameters. The resonance for the Leggett mode becomes sharper with increasing temperature. All of these light-induced collective modes along with density fluctuations contribute to the third-harmonic generation. We also predict an experimental possibility of optical detection of the Leggett mode.

  18. Visible-light-induced photocatalytic reduction of Cr(VI) with coupled Bi2O3/TiO2 photocatalyst and the synergistic bisphenol A oxidation.

    Science.gov (United States)

    Yang, Juan; Dai, Jun; Li, Jiantong

    2013-04-01

    Coupled Bi2O3/TiO2 photocatalysts were fabricated by sol-gel and hydrothermal methods and characterized using various spectroscopy techniques. Photocatalytic reduction of Cr(VI) in aqueous solution, together with the synergistic effect of photodegradation of bisphenol A (BPA), was investigated using these coupled Bi2O3/TiO2 under visible-light irradiation. Coupling of Bi2O3 inhibited the phase transformation from anatase to rutile and extended absorption region to visible light. Bi ions did not enter TiO2 lattice and were more likely to bond with oxygen atoms to form Bi2O3 on the surface of TiO2. Photovoltage signals in visible range revealed the effective interfacial charge transfer between Bi2O3 and TiO2. Two percent Bi2O3/TiO2 exhibited the highest photocatalytic activity of visible-light-induced reduction of Cr(VI). The addition of BPA effectively increased the photocatalytic reduction of Cr(VI). Simultaneously, the presence of Cr(VI) promoted the degradation of BPA, which was demonstrated by the investigation of TOC removal yield and generated intermediates. A possible mechanism of photocatalytic reduction of Cr(VI) and degradation of BPA in Bi2O3/TiO2 system was proposed. The synergistic effect, observed between reduction of Cr(VI) and degradation of BPA, provides beneficial method for environmental remediation and purification of the complex wastewater.

  19. I - Template Metaprogramming for Massively Parallel Scientific Computing - Expression Templates

    CERN Document Server

    CERN. Geneva

    2016-01-01

    Large scale scientific computing raises questions on different levels ranging from the fomulation of the problems to the choice of the best algorithms and their implementation for a specific platform. There are similarities in these different topics that can be exploited by modern-style C++ template metaprogramming techniques to produce readable, maintainable and generic code. Traditional low-level code tend to be fast but platform-dependent, and it obfuscates the meaning of the algorithm. On the other hand, object-oriented approach is nice to read, but may come with an inherent performance penalty. These lectures aim to present he basics of the Expression Template (ET) idiom which allows us to keep the object-oriented approach without sacrificing performance. We will in particular show to to enhance ET to include SIMD vectorization. We will then introduce techniques for abstracting iteration, and introduce thread-level parallelism for use in heavy data-centric loads. We will show to to apply these methods i...

  20. Structural, Magnetic, and Photomagnetic Studies of a Mononuclear Iron(II) Derivative Exhibiting an Exceptionally Abrupt Spin Transition. Light-Induced Thermal Hysteresis Phenomenon.

    Science.gov (United States)

    Létard, Jean-François; Guionneau, Philippe; Rabardel, Louis; Howard, Judith A. K.; Goeta, Andres E.; Chasseau, Daniel; Kahn, Olivier

    1998-08-24

    The new spin-crossover compound Fe(PM-BiA)(2)(NCS)(2) with PM-BiA = N-(2-pyridylmethylene)aminobiphenyl has been synthesized. The temperature dependence of chi(M)T (chi(M) = molar magnetic susceptibility and T = temperature) has revealed an exceptionally abrupt transition between low-spin (LS) (S = 0) and high-spin (HS) (S = 2) states with a well-reproducible hysteresis loop of 5 K (T(1/2) downward arrow = 168 K and T(1/2) upward arrow = 173 K). The crystal structure has been determined both at 298 K in the HS state and at 140 K in the LS state. The spin transition takes place without change of crystallographic space group (Pccn with Z = 4). The determination of the intermolecular contacts in the LS and HS forms has revealed a two-dimensional structural character. The enthalpy and entropy variations, DeltaH and DeltaS, associated with the spin transition have been deduced from heat capacity measurements. DeltaS (= 58 J K(-)(1) mol(-)(1)) is larger than for other spin transition bis(thiocyanato) iron(II) derivatives. At 10 K the well-known LIESST (light-induced excited spin state trapping) effect has been observed within the SQUID cavity, by irradiating a single crystal or a powder sample with a Kr(+) laser coupled to an optical fiber. The magnetic behavior recorded under light irradiation in the warming and cooling modes has revealed a light-induced thermal hysteresis (LITH) effect with 35 LS relaxation after LIESST has been found to deviate from first-order kinetics. The kinetics has been investigated between 10 and 78 K. A thermally activated relaxation behavior at elevated temperatures and a nearly temperature independent tunneling mechanism at low temperatures have been observed. The slow rate of tunneling from the metastable HS state toward the ground LS state may be explained by the unusually large change in Fe-N bond lengths between these two states.

  1. Templated growth of graphenic materials

    Energy Technology Data Exchange (ETDEWEB)

    Nicholas, Nolan W; Connors, L Matthew [Department of Physics, Rice University, 6100 Main, Houston, TX (United States); Ding, Feng [Institute of Textile and Clothing, Hong Kong Polytechnic University, Kowloon (Hong Kong); Yakobson, Boris I [Department of Mechanical Engineering and Materials Science, Rice University, 6100 Main, Houston, TX (United States); Schmidt, Howard K; Hauge, Robert H [Richard E Smalley Institute for Nanoscale Science and Technology, Rice University, 6100 Main, Houston, TX (United States)], E-mail: nolan.nicholas@matricresearch.com

    2009-06-17

    A novel strategy is proposed for the topologically controlled synthesis of extended graphenic sheets by additively reacting carbon into a pre-existing graphene sheet which is on top of a templating substrate. This concept is implemented and demonstrated using chemical vapor deposition (CVD). Novel morphological features observed in this study suggest unusual aspects of the CVD growth process. CVD results demonstrate the basic soundness of the synthesis strategy but highlight the sensitivity of the process to certain types of disruption and the need for alternative forms of embodiment.

  2. A template for design personas

    DEFF Research Database (Denmark)

    Nielsen, Lene; Storgaard Nielsen, Kira; Stage, Jan

    2015-01-01

    from 13 companies and compares these to an analysis of recommendations from 11 templates from literature. Furthermore, 28 interviews with Danish practitioners with experience in using personas are analyzed for content on persona descriptions. The study finds that a Danish persona style has developed...... that is different from the recommendations in the lack of marketing and business related information and the absence of goals as differentiator for personas. Furthermore, the inspiration and knowledge on personas originates from co-workers and seminars and not much from literature. This indicates that the community...

  3. A Template for Design Personas:

    DEFF Research Database (Denmark)

    Nielsen, Lene; Hansen, Kira Storgaard; Stage, Jan;

    2015-01-01

    The persona method is gaining widespread use and support. Many researchers have reported from single cases and from novel domains on how they have used the method. However, the way companies and design groups describe personas has not been the focus of attention. This paper analyses 47 descriptions...... from 13 companies and compares these to an analysis of recommendations from 11 templates from literature. Furthermore, 28 interviews with Danish practitioners with experience in using personas are analyzed for content on persona descriptions. The study finds that a Danish persona style has developed...

  4. MWCNT/WO{sub 3} nanocomposite photoanode for visible light induced water splitting

    Energy Technology Data Exchange (ETDEWEB)

    Yousefzadeh, Samira [Physics Department, Sharif University of Technology, P.O. Box 11155-9161, Tehran (Iran, Islamic Republic of); Reyhani, Ali [Physics Department, Faculty of Science, Imam Khomeini International University, P.O. Box 34149-16818, Qazvin (Iran, Islamic Republic of); Naseri, Naimeh [Physics Department, Sharif University of Technology, P.O. Box 11155-9161, Tehran (Iran, Islamic Republic of); Moshfegh, Alireza Z., E-mail: moshfegh@sharif.edu [Physics Department, Sharif University of Technology, P.O. Box 11155-9161, Tehran (Iran, Islamic Republic of); Institute for Nanoscience and Nanotechnology, Sharif University of Technology, P.O. Box 14588-89694, Tehran (Iran, Islamic Republic of)

    2013-08-15

    The Multi-walled carbon nanotube (MWCNT)/WO{sub 3} nanocomposite thin films with different MWCNT’s weight percentages were prepared by sol–gel method as visible light induced photoanode in water splitting reaction. Weight percentage of MWCNT in the all nanocomposite thin films was confirmed by TGA/DSC analysis. According to XPS analysis, oxygenated groups at the surface of the MWCNT and stoichiometric formation of WO{sub 3} thin films were determined, while the crystalline structure of the nanocomposite samples was studied by XRD indicating (0 0 2) peak of MWCNT in the monoclinic phase of WO{sub 3}. The influence of different weight percentage (wt%) of MWCNT on WO{sub 3} photoactivity showed that the electron conductivity, charge transfer and electron life time had improved as compared with the pure WO{sub 3}. Based on linear sweep voltammetry and chronoamperometry measurements, the (1 wt%) MWCNT/WO{sub 3} nanocomposite thin films photoanode has a maximum photocurrent density of ∼4.5 A/m{sup 2} and electron life time of about 57 s. - Graphical abstract: Photocurrent density versus time at constant potential (0.7 V) for the WO{sub 3} films containing different MWCNT weight percentages annealed at 400 °C under 1000 Wm{sup −2} visible photo-illumination. Display Omitted - Highlights: • MWCNT/ WO{sub 3} nanocomposite thin films were synthesized using sol–gel derived method. • TGA/DSC confirmed the weight percentage of MWCNT in the all nanocomposite thin films. • XPS analysis revealed that WO{sub 3} was attached on the oxygenated group of MWCNT surface. • The Highest Photoelectrochemical activity is achieved for (1 wt%)MWCNT/WO{sub 3} thin film.

  5. Dietary supplement enriched in antioxidants and omega-3 protects from progressive light-induced retinal degeneration.

    Directory of Open Access Journals (Sweden)

    Khaoula Ramchani-Ben Othman

    Full Text Available In the present study, we have evaluated one of the dietary supplements enriched with antioxidants and fish oil used in clinical care for patient with age-related macular degeneration. Rats were orally fed by a gastric canula daily with 0.2 ml of water or dietary supplement until they were sacrificed. After one week of treatment, animals were either sacrificed for lipid analysis in plasma and retina, or used for evaluation of rod-response recovery by electroretinography (ERG followed by their sacrifice to measure rhodopsin content, or used for progressive light-induced retinal degeneration (PLIRD. For PLIRD, animals were transferred to bright cyclic light for one week. Retinal damage was quantified by ERG, histology and detection of apoptotic nuclei. Animals kept in dim-cyclic-light were processed in parallel. PLIRD induced a thinning of the outer nuclear layer and a reduction of the b-wave amplitude of the ERG in the water group. Retinal structure and function were preserved in supplemented animals. Supplement induced a significant increase in omega-3 fatty acids in plasma by 168% for eicosapentaenoic acid (EPA, 142% for docosapentaenoic acid (DPA and 19% for docosahexaenoic acid (DHA and a decrease in the omega-6 fatty acids, DPA by 28%. In the retina, supplement induced significant reduction of linolenic acid by 67% and an increase in EPA and DPA by 80% and 72%, respectively, associated with significant decrease in omega-6 DPA by 42%. Supplement did not affect rhodopsin content or rod-response recovery. The present data indicate that supplement rapidly modified the fatty acid content and induced an accumulation of EPA in the retina without affecting rhodopsin content or recovery. In addition, it protected the retina from oxidative stress induced by light. Therefore, this supplement might be beneficial to slow down progression of certain retinal degeneration.

  6. Polychromatic light-induced osteogenic activity in 2D and 3D cultures.

    Science.gov (United States)

    Ülker, Nazife; Çakmak, Anıl S; Kiremitçi, Arlin S; Gümüşderelioğlu, Menemşe

    2016-11-01

    Photobiomodulation (PBM) has been applied to manipulate cellular responses by using monochromatic light in different wavelengths from ultraviolet (UV) to infrared (IR) region. Until now, an effective wavelength has not been revealed to induce proliferation and/or differentiation of cells. Therefore, in the presented study, we decided to use a specially designed plasma arc light source providing wavelengths between 590 and 1500 nm in order to investigate its biomodulatory effects on chitosan scaffold-supported three-dimensional (3D) cell cultures. For comparison, two-dimensional (2D) cell cultures were also carried out in tissue-culture polystyrene dishes (TCPS). The results showed that light-induced temperature rise did not affect cells when the distance between the light source and the cells was 10 cm and the frequency of administration was daily. Moreover, light was applied for 5 and 10 min to the cells in TCPS and in chitosan scaffold groups, respectively. Cell culture studies under static conditions indicated that polychromatic light significantly stimulated bone nodule formation via the prolonged cell survival and stimulated differentiation of MC3T3-E1 preosteoblastic cells in both TCPS and chitosan scaffold groups. In conclusion, specially designed plasma arc light source used in this study induces formation of bone tissue and so, this light source is proposed as an appropriate system for in vitro bone tissue engineering applications. Statistical analyses were performed with one-way ANOVA by using GraphPad Instat software and standard deviations were calculated by using data of three parallel samples for each group.

  7. Gibberellins negatively regulate light-induced nitrate reductase activity in Arabidopsis seedlings.

    Science.gov (United States)

    Zhang, Yongqiang; Liu, Zhongjuan; Liu, Rongzhi; Wang, Liguang; Bi, Yurong

    2011-12-15

    In the present study, the role of phytohormone gibberellins (GAs) on regulating the nitrate reductase (NR) activity was tested in Arabidopsis seedlings. The NR activity in light-grown Col-0 seedlings was reduced by exogenous GA₃ (an active form of GAs), but enhanced by exogenous paclobutrazol (PAC, a gibberellin biosynthesis inhibitor), suggesting that GAs negatively regulate the NR activity in light-grown seedlings. Light is known to influence the NR activity through both photosynthesis and phytochromes. When etiolated seedlings were transferred to white or red light, both exogenously applied GA₃ and PAC were found to function on the NR activity only in the presence of sucrose, implying that GAs are not involved in light signaling-induced but negatively regulate photoproducts-induced NR activity. NR is regulated by light mainly at two levels: transcript level and post-translational level. Our reverse transcription (RT)-PCR assays showed that GAs did not affect the transcript levels of NIA1 and NIA2, two genes that encode NR proteins. But the divalent cations (especially Mg²⁺) were required for GAs negative regulation of NR activity, in view of the importance of divalent cations during the process of post-translational regulation of NR activity, which indicates that GAs very likely regulate the NR activity at the post-translational level. In the following dark-light shift analyses, GAs were found to accelerate dark-induced decrease, but retard light-induced increase of the NR activity. Furthermore, it was observed that application of G₃ or PAC could impair diurnal variation of the NR activity. These results collectively indicate that GAs play a negative role during light regulation of NR activity in nature.

  8. Dietary Supplement Enriched in Antioxidants and Omega-3 Protects from Progressive Light-Induced Retinal Degeneration

    Science.gov (United States)

    Ramchani-Ben Othman, Khaoula; Cercy, Christine; Amri, Mohamed; Doly, Michel; Ranchon-Cole, Isabelle

    2015-01-01

    In the present study, we have evaluated one of the dietary supplements enriched with antioxidants and fish oil used in clinical care for patient with age-related macular degeneration. Rats were orally fed by a gastric canula daily with 0.2 ml of water or dietary supplement until they were sacrificed. After one week of treatment, animals were either sacrificed for lipid analysis in plasma and retina, or used for evaluation of rod-response recovery by electroretinography (ERG) followed by their sacrifice to measure rhodopsin content, or used for progressive light-induced retinal degeneration (PLIRD). For PLIRD, animals were transferred to bright cyclic light for one week. Retinal damage was quantified by ERG, histology and detection of apoptotic nuclei. Animals kept in dim-cyclic-light were processed in parallel. PLIRD induced a thinning of the outer nuclear layer and a reduction of the b-wave amplitude of the ERG in the water group. Retinal structure and function were preserved in supplemented animals. Supplement induced a significant increase in omega-3 fatty acids in plasma by 168% for eicosapentaenoic acid (EPA), 142% for docosapentaenoic acid (DPA) and 19% for docosahexaenoic acid (DHA) and a decrease in the omega-6 fatty acids, DPA by 28%. In the retina, supplement induced significant reduction of linolenic acid by 67% and an increase in EPA and DPA by 80% and 72%, respectively, associated with significant decrease in omega-6 DPA by 42%. Supplement did not affect rhodopsin content or rod-response recovery. The present data indicate that supplement rapidly modified the fatty acid content and induced an accumulation of EPA in the retina without affecting rhodopsin content or recovery. In addition, it protected the retina from oxidative stress induced by light. Therefore, this supplement might be beneficial to slow down progression of certain retinal degeneration. PMID:26042773

  9. One-Dimensional Organic-Inorganic Nanocomposite Synthesized with Single-Walled Carbon Nanotube Templates

    Directory of Open Access Journals (Sweden)

    Wei Li

    2014-08-01

    Full Text Available This study reports on single-walled carbon nanotubes (SWCNT as templates for the preparation of 1D porous organic-inorganic hybrid composites. The in situ deposited SWCNT were sputter coated with Sn metal and thermally oxidized in air to form a SnO2/SWCNT nanowire framework on SiO2/Si substrate. Poly(acrylic acid (PAA was coated onto this scaffold through UV light-induced radical polymerization, which resulted in the final formation of hybrid composites. The structures of hybrid composites were investigated by scanning electron microscopy, transmission electron microscopy, infrared spectroscopy, and Raman spectroscopy. The results show that PAA was successfully coated and the structural advantage of nanowire was fairly maintained, which indicates that this framework is very stable for organic functionalization in solution. The simplicity of this method for the formation of porous organic-inorganic hybrid composites provides a potential application for nanoelectronic devices.

  10. Hard template synthesis of metal nanowires

    Directory of Open Access Journals (Sweden)

    Go eKawamura

    2014-11-01

    Full Text Available Metal nanowires (NWs have attracted much attention because of their high electron conductivity, optical transmittance and tunable magnetic properties. Metal NWs have been synthesized using soft templates such as surface stabilizing molecules and polymers, and hard templates such as anodic aluminum oxide, mesoporous oxide, carbon nanotubes. NWs prepared from hard templates are composites of metals and the oxide/carbon matrix. Thus, selecting appropriate elements can simplify the production of composite devices. The resulting NWs are immobilized and spatially arranged, as dictated by the ordered porous structure of the template. This avoids the NWs from aggregating, which is common for NWs prepared with soft templates in solution. Herein, the hard template synthesis of metal NWs is reviewed, and the resulting structures, properties and potential applications are discussed.

  11. Vertical Carbon Nanotube Device in Nanoporous Templates

    Science.gov (United States)

    Maschmann, Matthew Ralph (Inventor); Fisher, Timothy Scott (Inventor); Sands, Timothy (Inventor); Bashir, Rashid (Inventor)

    2014-01-01

    A modified porous anodic alumina template (PAA) containing a thin CNT catalyst layer directly embedded into the pore walls. CNT synthesis using the template selectively catalyzes SWNTs and DWNTs from the embedded catalyst layer to the top PAA surface, creating a vertical CNT channel within the pores. Subsequent processing allows for easy contact metallization and adaptable functionalization of the CNTs and template for a myriad of applications.

  12. Improvement on electrical properties of screen-printed silicon solar cells by light-induced electroplating of silver

    Science.gov (United States)

    Li, Tao; Wang, Wenjing

    2016-10-01

    The total power losses are analyzed based on two-layer electrode of light-induced electroplating after screen printing. By the introduction of scale factor in the calculation, optical losses are closer to the actual condition. Optimized two-layer contact of front side could diminish power losses distinctly and improve the current-voltage (I-V) characteristic of crystalline silicon solar cells. The relative increments of I-V parameters as a function of electroplating time are measured. The quantitative comparison of analytical results between half-ellipse shape model and half-circled shape model is performed. The numerical simulation results and experimental data show good agreement. Due to the successful verification, the simulation results could be used to optimize the two-layer electrode structure and light-induced electroplating process.

  13. Light-induced conformational changes of the chromophore and the protein in phytochromes: bacterial phytochromes as model systems.

    Science.gov (United States)

    Scheerer, Patrick; Michael, Norbert; Park, Jung Hee; Nagano, Soshichiro; Choe, Hui-Woog; Inomata, Katsuhiko; Borucki, Berthold; Krauss, Norbert; Lamparter, Tilman

    2010-04-26

    Recombinant phytochromes Agp1 and Agp2 from Agrobacterium tumefaciens are used as model phytochromes for biochemical and biophysical studies. In biliverdin binding phytochromes the site for covalent attachment of the chromophore lies in the N-terminal region of the protein, different from plant phytochromes. The issue which stereochemistry the chromophore adopts in the so-called Pr and Pfr forms is addressed by using a series of locked chromophores which form spectrally characteristic adducts with Agp1 and Agp2. Studies on light-induced conformational changes of Agp1 give an insight into how the intrinsic histidine kinase is modulated by light. Comparison of the crystal structure of an Agp1 fragment with other phytochrome crystal structures supports the idea that a light induced rearrangement of subunits within the homodimer modulates the activity of the kinase.

  14. Light-induced changes in an alkali metal atomic vapor cell coating studied by X-ray photoelectron spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Hibberd, A. M.; Bernasek, S. L. [Department of Chemistry, Princeton University, Princeton, New Jersey 08544 (United States); Seltzer, S. J. [Department of Chemistry, University of California, Berkeley, California 94720 (United States); Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Balabas, M. V. [Department of Physics, Saint-Petersburg State University, St. Petersburg 198504 (Russian Federation); Morse, M. [Department of Materials Science Engineering, Boise State University, Boise, Idaho 83725 (United States); Budker, D. [Department of Physics, University of California, Berkeley, California 94720-7300 (United States); Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

    2013-09-07

    The light-induced desorption of Rb atoms from a paraffin coating is studied with depth-profiling X-ray photoelectron spectroscopy (XPS) using tunable synchrotron radiation. Following Rb exposure, shifts of the C1s signal to higher binding energies, as well as the appearance of lower binding energy components in the O1s region, were observed. These effects were diminished after irradiation with desorbing light. Additionally, following desorbing-light irradiation, changes in the depth-dependent concentration of carbon were observed. These observations offer an insight into the microscopic changes that occur during light-induced atomic desorption and demonstrate the utility of XPS in understanding atom-coating interactions.

  15. Blue and red light-induced germination of resting spores in the red-tide diatom Leptocylindrus danicus.

    Science.gov (United States)

    Shikata, Tomoyuki; Iseki, Mineo; Matsunaga, Shigeru; Higashi, Sho-ichi; Kamei, Yasuhiro; Watanabe, Masakatsu

    2011-01-01

    Photophysiological and pharmacological approaches were used to examine light-induced germination of resting spores in the red-tide diatom Leptocylindrus danicus. The equal-quantum action spectrum for photogermination had peaks at about 440 nm (blue light) and 680 nm (red light), which matched the absorption spectrum of the resting spore chloroplast, as well as photosynthetic action spectra reported for other diatoms. DCMU, an inhibitor of photosynthetic electron flow near photosystem II, completely blocked photogermination. These results suggest that the photosynthetic system is involved in the photoreception process of light-induced germination. Results of pharmacological studies of the downstream signal transduction pathway suggested that Ca(2+) influx is the closest downstream neighbor, followed by steps involving calmodulin, nitric oxide synthase, guanylyl cyclase, protein-tyrosine-phosphatase, protein kinase C and actin polymerization and translation.

  16. Oligonucleotide-templated chemical reactions: pushing the boundaries of a nature-inspired process.

    Science.gov (United States)

    Percivalle, Claudia; Bartolo, Jean-François; Ladame, Sylvain

    2013-01-07

    Widespread in nature, oligonucleotide-templated reactions of phosphodiester bond formation have inspired chemists who are now applying this elegant strategy to the catalysis of a broad range of otherwise inefficient reactions. This review highlights the increasing diversity of chemical reactions that can be efficiently catalysed by an oligonucleotide template, using Watson-Crick base-pairing to bring both reagents in close enough proximity to react, thus increasing significantly their effective molarity. The applications of this elegant concept for nucleic acid sensing and controlled organic synthesis will also be discussed.

  17. Nucleobase-templated polymerization: copying the chain length and polydispersity of living polymers into conjugated polymers.

    Science.gov (United States)

    Lo, Pik Kwan; Sleiman, Hanadi F

    2009-04-01

    Conjugated polymers synthesized by step polymerization mechanisms typically suffer from poor molecular weight control and broad molecular weight distributions. We report a new method which uses nucleobase recognition to read out and efficiently copy the controlled chain length and narrow molecular weight distribution of a polymer template generated by living polymerization, into a daughter conjugated polymer. Aligning nucleobase-containing monomers on their complementary parent template using hydrogen-bonding interactions, and subsequently carrying out a Sonogashira polymerization, leads to the templated synthesis of a conjugated polymer. Remarkably, this daughter strand is found to possess a narrow molecular weight distribution and a chain length nearly equivalent to that of the parent template. On the other hand, nontemplated polymerization or polymerization with the incorrect template generates a short conjugated oligomer with a significantly broader molecular weight distribution. Hence, nucleobase-templated polymerization is a useful tool in polymer synthesis, in this case allowing the use of a large number of polymers generated by living methods, such as anionic polymerization, controlled radical polymerizations (NMP, ATRP, and RAFT) and other mechanisms to program the structure, length, and molecular weight distribution of polymers normally generated by step polymerization methods and significantly enhance their properties.

  18. Influence of template fill in graphoepitaxy DSA

    Science.gov (United States)

    Doise, Jan; Bekaert, Joost; Chan, Boon Teik; Hong, SungEun; Lin, Guanyang; Gronheid, Roel

    2016-03-01

    Directed self-assembly (DSA) of block copolymers (BCP) is considered a promising patterning approach for the 7 nm node and beyond. Specifically, a grapho-epitaxy process using a cylindrical phase BCP may offer an efficient solution for patterning randomly distributed contact holes with sub-resolution pitches, such as found in via and cut mask levels. In any grapho-epitaxy process, the pattern density impacts the template fill (local BCP thickness inside the template) and may cause defects due to respectively over- or underfilling of the template. In order to tackle this issue thoroughly, the parameters that determine template fill and the influence of template fill on the resulting pattern should be investigated. In this work, using three process flow variations (with different template surface energy), template fill is experimentally characterized as a function of pattern density and film thickness. The impact of these parameters on template fill is highly dependent on the process flow, and thus pre-pattern surface energy. Template fill has a considerable effect on the pattern transfer of the DSA contact holes into the underlying layer. Higher fill levels give rise to smaller contact holes and worse critical dimension uniformity. These results are important towards DSA-aware design and show that fill is a crucial parameter in grapho-epitaxy DSA.

  19. CHUP1 mediates actin-based light-induced chloroplast avoidance movement in the moss Physcomitrella patens.

    Science.gov (United States)

    Usami, Hiroka; Maeda, Takuma; Fujii, Yusuke; Oikawa, Kazusato; Takahashi, Fumio; Kagawa, Takatoshi; Wada, Masamitsu; Kasahara, Masahiro

    2012-12-01

    Chloroplasts change their intracellular distribution in response to light intensity. CHUP1 (CHLOROPLAST UNUSUAL POSITIONING1) is indispensable for this response in Arabidopsis thaliana. However, involvement of CHUP1 in light-induced chloroplast movement is unknown in other plants. In this study, CHUP1 orthologues were isolated from a moss, Physcomitrella patens, and a fern, Adiantum capillus-veneris, by cDNA library screening and PCR cloning based on the P. patens genome sequence. Functional motifs found in CHUP1 of A. thaliana were conserved among the CHUP1 orthologues. In addition to the putative functional regions, the C-terminal regions (approximately 250 amino acids), which are unique in CHUP1s, were highly conserved. Green fluorescent protein (GFP) fusions of P. patens CHUP1s (PpCHUP1A, PpCHUP1B and PpCHUP1C) were transiently expressed in protoplast cells. All GFP fusions were localized on the chloroplasts. Light-induced chloroplast avoidance movement of chup1 disruptants of P. patens was examined in the presence of cytoskeletal inhibitors because of the utilization of both microtubules and actin filaments for the movement in P. patens. When actin filaments were disrupted by cytochalasin B, the wild type (WT) and all chup1 disruptants showed chloroplast avoidance movement. However, when microtubules were disrupted by Oryzalin, chloroplasts in ∆chup1A and ∆chup1A/B rarely moved and stayed in the strong light-irradiated area. On the other hand, WT, ∆chup1B and ∆chup1C showed chloroplast avoidance movement. These results suggest that PpCHUP1A predominantly mediates the actin-based light-induced chloroplast avoidance movement. This study reveals that CHUP1 functions on the chloroplasts and is involved in the actin-based light-induced chloroplast avoidance movement in P. patens.

  20. Hydrogen peroxide generated by NADPH oxidase is involved in high blue-light-induced chloroplast avoidance movements in Arabidopsis

    Science.gov (United States)

    Wen, Feng; Xing, Da; Zhang, Lingrui

    2009-08-01

    One of the most important functions of blue light is to induce chloroplast movements by reducing the damage to photosynthetic machinery under excess light. Hydrogen peroxide (H2O2), generated by various environmental stimuli, can act as a signaling molecule that regulates a number of developmental processes and environmental responses. To investigate whether H2O2 is involved in high blue light-induced chloroplast avoidance movements, we use luminescence spectrometer to observe H2O2 generation with the assistance of the fluorescence probe dichlorofluorescin diacetate (H2DCF-DA). After treatment with high blue light, a large quantity of H2O2 indicated by the fluorescence intensity of DCF is produced in a dose-dependent manner in leaf strip of Arabidopsis. Enzymatic assay shows that the activity of NADPH oxidase, which is a major site for H2O2 generation, also rapidly increases in treated strips. Exogenously applied H2O2 can promote the high blue light-induced chloroplast movements. Moreover, high blue light-induced H2O2 generation can be abolished completely by addition of exogenous catalase (CAT), and partly by diphenylene iodonium (DPI) and dichlorophenyl dimethylurea (DCMU), which are an NADPH oxidase inhibitor and a blocker of electron transport chain. And subsequent chloroplast movements can be abolished by CAT and DPI, but not by DCMU. These results presented here suggested that high blue light can induce oxidative burst, and NADPH oxidase as a major producer for H2O2 is involved in blue light-induced chloroplast avoidance movements.

  1. Comparative analyses of light-induced anthocyanin accumulation and gene expression between the ray florets and leaves in chrysanthemum.

    Science.gov (United States)

    Hong, Yan; Yang, Li-Wen; Li, Meng-Ling; Dai, Si-Lan

    2016-06-01

    Light is one of the key environmental factors that affect anthocyanin biosynthesis. However, the underlying molecular mechanism remains unclear, and many problems regarding phenotypic change and corresponding gene regulation have not been solved. In the present study, comparative analyses of light-induced anthocyanin accumulation and gene expression between the ray florets and leaves were performed in Chrysanthemum × morifolium 'Purple Reagan'. After contrasting the variations in the flower color phenotype and relative pigment content, as well as expression patterns of structural and regulator genes responsible for anthocyanin biosynthesis and photoreceptor between different plant organs under light and dark conditions, we concluded that (1) both the capitulum and foliage are key organs responding to light for chrysanthemum coloration; (2) compared with flavones, shading makes a greater decrease on the anthocyanins accumulation; (3) most of the structural and regulatory genes in the light-induced anthocyanin pathway specifically express in the ray florets; and (4) CmCHS, CmF3H, CmF3'H, CmANS, CmDFR, Cm3GT, CmMYB5-1, CmMYB6, CmMYB7-1, CmbHLH24, CmCOP1 and CmHY5 are key genes for light-induced anthocyanin biosynthesis in chrysanthemum ray florets, while on the transcriptional level, the expressions of CmPHYA, CmPHYB, CmCRY1a, CmCRY1b and CmCRY2 are insignificantly changed. Moreover, the inferred comprehensive effect of multiple signals on the accumulation of anthocyanins and transmission channel of light signal that exist between the leaves and ray florets were further discussed. These results further our understanding of the relationship between the gene expression and light-induced anthocyanin biosynthesis, and lay foundations for the promotion of the molecular breeding of novel flower colors in chrysanthemums.

  2. Light-induced damage and its diagnosis in two-photon excited autofluorescence imaging of retinal pigment epithelium cells

    Science.gov (United States)

    Chen, Danni; Qu, Junle; Xu, Gaixia; Zhao, Lingling; Niu, Hanben

    2007-05-01

    In this paper, a novel method for the differentiation of the retinal pigment epithelium (RPE) cells after light-induced damage by two-photon excitation is presented. Fresh samples of RPE cells of pig eyes are obtained from local slaughterhouse. Light-induced damage is produced by the output from Ti: sapphire laser which is focused onto the RPE layer. We study the change of the autofluorescence properties of RPE after two-photon excitation with the same wavelength. Preliminary results show that after two-photon excitation, there are two clear changes in the emission spectrum. The first change is the blue-shift of the emission peak. The emission peak of the intact RPE is located at 592nm, and after excitation, it shifts to 540nm. It is supposed that the excitation has led to the increased autofluorescence of flavin whose emission peak is located at 540nm. The second change is the increased intensity of the emission peak, which might be caused by the accelerated aging because the autofluorescence of RPE would increase during aging process. Experimental results indicate that two-photon excitation could not only lead to the damage of the RPE cells in multiphoton RPE imaging, but also provide an evaluation of the light-induced damage.

  3. Comparison between the standard SPM2 template and Korean-standard template in FDG-PET

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jung Hee; Lee, Byeong Il; Song, Ho Chun; Min, Jung Joon; Bom, Hee Seung [Chonnam National University Hospital, Gwangju (Korea, Republic of); Lee, Jae Sung [Seoul National University Hospital, Seoul (Korea, Republic of)

    2005-07-01

    The preprocessing step of statistical parametric mapping (SPM) requires the procedure of spatial normalization that consists of applying the nonlinear deformations needed to force every particular PET scan to match a reference template. The purpose of this study is to asses the statistic influence of using 2 different templates (the standard SPM2-PET template and Korean-standard PET template) in the normalization. We compared the regional metabolic patterns on 18F-FDG (fluorodeoxyglucose) images obtained from 4 patients with Alzheimers disease (AD) and 16 normal subjects. The statistical outcome of between- group comparison was analyzed with SPM2 and was applied into two levels of thresholds (an uncorrected P value of P <0.001, a corrected P value of P < 0.05). As a result, the most significant hypometabolic region was commonly found in the left temporal gyrus regardless of template type or thresholds. However, inconsistent results including different extent and the t-score statistics representing metabolic changes could be also observed between two templates. While the standard SPM2 template showed hypometabolic regions corresponding to Brodman area (BA) 7 and 9, Korean-standard template was not observed these regions. In addition, hypometabolic regions corresponding to BA 38 and 46 indicated not the standard SPM2 template but Korean-standard template. Statistic result showed that the standard SPM2 template effectively reflects the dorsal region of the brain while Korean-standard template is more sensitive to the medial region of the brain.

  4. Femtosecond study of light-induced fluorescence increase of the dark chromoprotein asFP595

    Energy Technology Data Exchange (ETDEWEB)

    Schuettrigkeit, Tanja A. [Department Chemie, Technische Universitaet Muenchen, 85747 Garching (Germany); Feilitzsch, Till von [Department Chemie, Technische Universitaet Muenchen, 85747 Garching (Germany); Kompa, Christian K. [Department Chemie, Technische Universitaet Muenchen, 85747 Garching (Germany); Lukyanov, Konstantin A. [Shemiakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow (Russian Federation); Savitsky, Alexander P. [A.N. Bach Institute of Biochemistry, Russian Academy of Sciences, Moscow (Russian Federation); Voityuk, Alexander A. [Institucio Catalana de Recerca i Estudis Avancats (ICREA), Institute of Computational Chemistry, Universitat de Girona (Spain); Michel-Beyerle, Maria E. [Department Chemie, Technische Universitaet Muenchen, 85747 Garching (Germany)], E-mail: michel-beyerle@ch.tum.de

    2006-04-21

    Femtosecond time-resolved spectroscopy is applied to study the mechanism of the light-induced increase of fluorescence quantum yield of the initially non-fluorescent (dark) chromoprotein asFP595. Spectroscopic and kinetic characteristics of this unique fluorescence 'kindling' phenomenon are: (i) the small Stokes shift of the dark chromophore consistent with either the zwitterion or the anion; (ii) the singlet excited state of the dark chromophore decaying predominantly with a time constant of {approx}320 fs corresponding to a fluorescence quantum yield {phi} {sub Fl} {<=} 10{sup -4}. Since ground state recovery occurs on the same time scale, this radiationless channel is assigned to internal conversion; (iii) the formation of the fluorescent species depending on the sequential absorption of two photons with a delay significantly exceeding the excitation pulse duration of 150 fs; (iv) the fluorescent species showing a red-shift of {approx}20 nm in absorption and emission, and an excited state lifetime of 2.2 ns. The ultrafast internal conversion of the excited dark state is attributed to the proximity of the S{sub 0} and S{sub 1} potential energy surfaces favored by the non-planarity of the chromophore as revealed in recent X-ray structures. Competing with internal conversion two different transformations of the chromophore structure are suggested which may be identified in a future X-ray structural analysis of the the photoconverted fluorescent state. The predominant kindling mechanism may be either (i) trans-cis isomerization or (ii) proton transfer between an excited zwitterion and the protein cleft. For mechanism (ii) the large dipole moment change of about 11 D upon S{sub 0}-S{sub 1} excitation of the chromophore would be crucial in order to initiate protein relaxation and deprotonation of a zwitterion. Both mechanisms are assumed to lead to a metastable planar structure responsible for the long-lived fluorescence of the chromophore &apos

  5. Light induced heterogeneous ozone processing on the pesticides adsorbed on silica particles

    Science.gov (United States)

    Socorro, J.; Désert, M.; Quivet, E.; Gligorovski, S.; Wortham, H.

    2013-12-01

    In France, in 2010, the sales of pesticides reached 1.8 billion euros for 61 900 tons of active ingredients, positioning France as a first European consumer of pesticides, as reported by the European Crop Protection Association. About 19 million hectares of crops are sprayed annually with pesticides, i.e., 35% of the total surface area of France. This corresponds to an average pesticide dose of 3.2 kg ha-1. The consumption of herbicide and fungicide is favoured in comparison to the use of insecticides in France and the other European countries, as well. The partitioning of pesticides between the gas and particulate phases influences the atmospheric fate of these compounds such as their photo-chemical degradation. There is much uncertainty concerning the behavior of the pesticides in the atmosphere. Especially, there is a gap of knowledge concerning the degradation of the pesticides induced by heterogeneous reactions in absence and especially in presence of solar light. Considering that most of the pesticides currently used are semi-volatile, it is of crucial importance to investigate the heterogeneous reactivity of particulate pesticides with light and with atmospheric oxidants such as ozone and OH radical. The aim of the present work is to evaluate the light induced heterogeneous ozonation of suspended pesticide particles. 8 pesticides (cyprodinil, deltamethrin, difenoconazole, fipronil, oxadiazon, pendimethalin, permethrin and tetraconazole) were chosen for their physico-chemical properties and their concentration levels in the PACA (Région Provence-Alpes-Côte d'Azur) region, France. Silica particles with well-known properties were chosen as model particles of atmospheric relevance. Kinetic rate constants were determined to allow estimate the atmospheric lifetimes relating to ozone. The rate constants were determined as follows: k = (6.6 × 0.2) 10-19, (7.2 × 0.3) 10-19, (5.1 × 0.5) 10-19, (3.9 × 0.3) 10-19 [cm3 molecules-1 s-1] for Cyprodinil

  6. 光致型形状记忆高分子材料%Light-Induced Shape Memory Polymer Materials

    Institute of Scientific and Technical Information of China (English)

    武元鹏; 林元华; 周莹; 左芳; 郑朝晖; 丁小斌

    2012-01-01

    形状记忆高分子材料是当前的研究热点之一,其中光致型形状记忆高分子材料凭借其独特的优势受到研究者的广泛关注。本文综述了光致型形状记忆高分子材料的研究进展,分别介绍了该类材料的特性、分类、工作机理、应用研究和发展趋势。根据不同的形状记忆机理将该类材料分为光化学反应型和光热效应型,并重点对这两种类型的形状记忆高分子材料进行了描述。最后,对光致型形状记忆高分子材料的存在问题、发展方向和应用前景进行了展望。%The research of shape memory polymer is a hot topic in the field of smart polymers. In recent years, as an important kind of shape memory polymers, the light-induced shape memory polymers have attracted great interest from researchers due to their unique properties. In this article, the progress in light-induced shape memory polymers is reviewed. The unique advantages, memory mechanism, applications and research trend of the shape memory polymers are introduced. In terms of the shape memory mechanism, light-induced shape memory polymers can be divided into two types, one is based on photochemical reactions, the other is based on light- induced heating. The shape memory polymers based on the two memory mechanisms are reviewed in detail. The applications of these materials are also discussed. Finally, the problems in light-induced shape memory polymers are pointed out, and the future development and applications of the polymers are prospected.

  7. A Template for Design Personas:

    DEFF Research Database (Denmark)

    Nielsen, Lene; Hansen, Kira Storgaard; Stage, Jan;

    2015-01-01

    The persona method is gaining widespread use and support. Many researchers have reported from single cases and from novel domains on how they have used the method. However, the way companies and design groups describe personas has not been the focus of attention. This paper analyses 47 descriptions...... from 13 companies and compares these to an analysis of recommendations from 11 templates from literature. Furthermore, 28 interviews with Danish practitioners with experience in using personas are analyzed for content on persona descriptions. The study finds that a Danish persona style has developed...... that is different from the recommendations in the lack of marketing and business related information and the absence of goals as differentiator for personas. Furthermore, the inspiration and knowledge on personas originates from co-workers and seminars and not much from literature. This indicates that the community...

  8. Testing by C++ template metaprograms

    CERN Document Server

    Pataki, Norbert

    2010-01-01

    Testing is one of the most indispensable tasks in software engineering. The role of testing in software development has grown significantly because testing is able to reveal defects in the code in an early stage of development. Many unit test frameworks compatible with C/C++ code exist, but a standard one is missing. Unfortunately, many unsolved problems can be mentioned with the existing methods, for example usually external tools are necessary for testing C++ programs. In this paper we present a new approach for testing C++ programs. Our solution is based on C++ template metaprogramming facilities, so it can work with the standard-compliant compilers. The metaprogramming approach ensures that the overhead of testing is minimal at runtime. This approach also supports that the specification language can be customized among other advantages. Nevertheless, the only necessary tool is the compiler itself.

  9. Screening for templates that promote crystallization

    NARCIS (Netherlands)

    Urbanus, J.; Roelands, C.P.M.; Horst, J.H. ter; Verdoes, D.; Jansens, P.J.

    2008-01-01

    In Situ Product Recovery (ISPR) applied in fermentation processes leads to improved yield and productivity of these processes. In principle, ISPR can be achieved using Template Induced Crystallization (TIC), which is one possible ISPR technique. With TIC, templates are added to the solution as a spe

  10. Template synthesis of ordered macroporous hydroxyapatite bioceramics.

    Science.gov (United States)

    Ji, Lijun; Jell, Gavin; Dong, Yixiang; Jones, Julian R; Stevens, Molly M

    2011-08-28

    Hydroxyapatite has found wide application in bone tissue engineering. Here we use a macroporous carbon template to generate highly ordered macroporous hydroxyapatite bioceramics composed of close-packed hollow spherical pores with interconnected channels. The template has advantages for the preparation of ordered materials.

  11. Indexing Images: Testing an Image Description Template.

    Science.gov (United States)

    Jorgensen, Corinne

    1996-01-01

    A template for pictorial image description to be used by novice image searchers in recording their descriptions of images was tested; image attribute classes derived in previous research were used to model the template. Results indicated that users may need training and/or more guidance to correctly assign descriptors to higher-level classes.…

  12. Solvable model for template coexistence in protocells

    CERN Document Server

    Fontanari, J F

    2012-01-01

    Compartmentalization of self-replicating molecules (templates) in protocells is a necessary step towards the evolution of modern cells. However, coexistence between distinct template types inside a protocell can be achieved only if there is a selective pressure favoring protocells with a mixed template composition. Here we study analytically a group selection model for the coexistence between two template types using the diffusion approximation of population genetics. The model combines competition at the template and protocell levels as well as genetic drift inside protocells. At the steady state, we find a continuous phase transition separating the coexistence and segregation regimes, with the order parameter vanishing linearly with the distance to the critical point. In addition, we derive explicit analytical expressions for the critical steady-state probability density of protocell compositions.

  13. Solvable model for template coexistence in protocells

    Science.gov (United States)

    Fontanari, J. F.; Serva, M.

    2013-02-01

    Compartmentalization of self-replicating molecules (templates) in protocells is a necessary step towards the evolution of modern cells. However, coexistence between distinct template types inside a protocell can be achieved only if there is a selective pressure favoring protocells with a mixed template composition. Here we study analytically a group selection model for the coexistence between two template types using the diffusion approximation of population genetics. The model combines competition at the template and protocell levels as well as genetic drift inside protocells. At the steady state, we find a continuous phase transition separating the coexistence and segregation regimes, with the order parameter vanishing linearly with the distance to the critical point. In addition, we derive explicit analytical expressions for the critical steady-state probability density of protocell compositions.

  14. Template Assembly for Detailed Urban Reconstruction

    KAUST Repository

    Nan, Liangliang

    2015-05-04

    We propose a new framework to reconstruct building details by automatically assembling 3D templates on coarse textured building models. In a preprocessing step, we generate an initial coarse model to approximate a point cloud computed using Structure from Motion and Multi View Stereo, and we model a set of 3D templates of facade details. Next, we optimize the initial coarse model to enforce consistency between geometry and appearance (texture images). Then, building details are reconstructed by assembling templates on the textured faces of the coarse model. The 3D templates are automatically chosen and located by our optimization-based template assembly algorithm that balances image matching and structural regularity. In the results, we demonstrate how our framework can enrich the details of coarse models using various data sets.

  15. Porous copper template from partially spark plasma-sintered Cu–Zn aggregate via dezincification

    Indian Academy of Sciences (India)

    M Mandal; D Singh; Gouthama; B S Murty; S Sangal; K Mondal

    2014-06-01

    Present work deals with the preparation of spark plasma-sintered Cu–Zn aggregate (5, 10 and 20 wt% Zn) with interfacial bonding only starting from elemental powders of Cu and Zn (99.9% purity) and subsequently making of porous template of Cu by dezincification. Sintering is done so as to achieve only interfacial bonding with the aim to maintain maximum potential difference between the Cu and Zn particles during dezincification process in various solutions, viz. 1 N HCl and 3.5 wt% NaCl solutions. X-ray diffraction, optical microscopy and SEM–EDS are carried out to examine microstructural evolution and subsequent changes in hardness with sintering temperatures and different Zn percentages. Dezincification and pore formation are conducted on sintered 0.5 mm thick 12 mm diameter disc samples. The size, distribution and nature of pores in porous templates of Cu are then investigated using optical microscopy and SEM–EDS analysis.

  16. [Exploration of research approaches of Chinese medicine's pharmacology based on "imprinting templates" (medical element) of supramolecules].

    Science.gov (United States)

    He, Fu-yuan; He, Hong; Deng, Kai-wen; Zhou, Yi-qun; Shi, Ji-lian; Liu, Wen-long; Yang, Yan-tao; Tang, Yu

    2015-11-01

    The paper, based on the previous publication as special impact of Chinese medicine theories on supramolcular chemistry, aims to analyze the natural origination for the Chinese medicine and to explain the special impact of "Qi chromatography" reaction on "imprinting templates" in supramolcular host of human being with Chinese medicine, in order to reveal the CM's properties of "medical element" with "imprinting templates" autonomisation generally took place in natural supramolecules, and also to discover that the CM's pharmacology are satisfied with its own approaches different form western pharmacology. It was decided, for CM's pharmacology guided by CM's theories, to "Qi chromatography" relations between the CM's ingredient groups and the meridian zang-fu viscera. The supramolcular chemistry played an all-through role in procession of making macro-regularities and special presentation on behavior of "Qi chromatography" impulse owning to the matching action of all kinds of ingredients on the meridian zang-fu viscera with similar "imprinting templates". The CM's pharmacology were guided by CM's theories, owing to its interpretation of supramolecular chemistry. The pharmacology was achieved to construct up completely on base of classical chemical single molecular bonds whereas the CM's pharmacology be configured to big building by way of "imprinting templates" as multi-weak bonds among "supramolecular society". CM's pharmacology was supramolcular pharmacology dealt with "molecular society" on the base of western pharmacology, and employed to double research approaches both math-physical quantitative representation on macroscope and qualitative analyses in microscope.

  17. "Bis-Click" Ligation of DNA: Template-Controlled Assembly, Circularisation and Functionalisation with Bifunctional and Trifunctional Azides.

    Science.gov (United States)

    Yang, Haozhe; Seela, Frank

    2017-03-08

    Ligation and circularisation of oligonucleotides containing terminal triple bonds was performed with bifunctional or trifunctional azides. Both reactions are high yielding. Template-assisted bis-click ligation of two individual non-complementary oligonucleotide strands was accomplished to yield heterodimers exclusively. In this context, the template fulfils two functions: it accelerates the ligation reaction and controls product assembly (heterodimer vs. homodimer formation). Intermolecular bis-click circularisation of one oligonucleotide strand took place without template assistance. For construction of oligonucleotides with terminal triple bonds in the nucleobase side chain, 7- or 5-functionalised 7-deaza-dA and dU residues were used. These oligonucleotides are directly accessible by solid-phase synthesis. When trifunctional azides were employed instead of bifunctional linkers, functionalisation of the remaining azido group was performed with small molecules such as 1-ethynyl pyrene, biotin propargyl amide or with ethynylated oligonucleotides. By this means, branched DNA was constructed.

  18. A Bayesian method for pulsar template generation

    CERN Document Server

    Imgrund, M; Kramer, M; Lesch, H

    2015-01-01

    Extracting Times of Arrival from pulsar radio signals depends on the knowledge of the pulsars pulse profile and how this template is generated. We examine pulsar template generation with Bayesian methods. We will contrast the classical generation mechanism of averaging intensity profiles with a new approach based on Bayesian inference. We introduce the Bayesian measurement model imposed and derive the algorithm to reconstruct a "statistical template" out of noisy data. The properties of these "statistical templates" are analysed with simulated and real measurement data from PSR B1133+16. We explain how to put this new form of template to use in analysing secondary parameters of interest and give various examples: We implement a nonlinear filter for determining ToAs of pulsars. Applying this method to data from PSR J1713+0747 we derive ToAs self consistently, meaning all epochs were timed and we used the same epochs for template generation. While the average template contains fluctuations and noise as unavoida...

  19. Multi-level modeling of light-induced stomatal opening offers new insights into its regulation by drought.

    Science.gov (United States)

    Sun, Zhongyao; Jin, Xiaofen; Albert, Réka; Assmann, Sarah M

    2014-11-01

    Plant guard cells gate CO2 uptake and transpirational water loss through stomatal pores. As a result of decades of experimental investigation, there is an abundance of information on the involvement of specific proteins and secondary messengers in the regulation of stomatal movements and on the pairwise relationships between guard cell components. We constructed a multi-level dynamic model of guard cell signal transduction during light-induced stomatal opening and of the effect of the plant hormone abscisic acid (ABA) on this process. The model integrates into a coherent network the direct and indirect biological evidence regarding the regulation of seventy components implicated in stomatal opening. Analysis of this signal transduction network identified robust cross-talk between blue light and ABA, in which [Ca2+]c plays a key role, and indicated an absence of cross-talk between red light and ABA. The dynamic model captured more than 10(31) distinct states for the system and yielded outcomes that were in qualitative agreement with a wide variety of previous experimental results. We obtained novel model predictions by simulating single component knockout phenotypes. We found that under white light or blue light, over 60%, and under red light, over 90% of all simulated knockouts had similar opening responses as wild type, showing that the system is robust against single node loss. The model revealed an open question concerning the effect of ABA on red light-induced stomatal opening. We experimentally showed that ABA is able to inhibit red light-induced stomatal opening, and our model offers possible hypotheses for the underlying mechanism, which point to potential future experiments. Our modelling methodology combines simplicity and flexibility with dynamic richness, making it well suited for a wide class of biological regulatory systems.

  20. Templated Growth of Magnetic Recording Media

    Science.gov (United States)

    Sundar, Vignesh

    Current and potential next-generation magnetic recording technologies are based on the writing and reading of bits on a magnetic thin film with a granular microstructure, with grains of the magnetic material surrounded by an amorphous segregant. In order to realize the highest achievable data storage capabilities, there is a need for better control of the magnetic media microstructure, particularly in terms of minimizing grain size and grain boundary thickness distributions. In this work, a guided magnetic media growth is attempted by creating a pre-fabricated template with a specific material and morphology. The template is designed in such a way that, when magnetic media consisting of the magnetic alloy and segregant are sputtered, the sites on the template result in a controlled two-phase growth of magnetic media. The template is fabricated using self-assembling block copolymers, which can be used to fabricate nanostructures with a regular hexagonal lattice of spheres of one block in the other's matrix. These are then used as etch-masks to fabricate the template. In this thesis, we describe the approach used to fabricate these templates and demonstrate the two-phase growth of magnetic recording media. In such an approach, the magnetic grain size is defined by the uniform pitch of the block copolymer pattern, resulting in a uniform microstructure with much better grain size distribution than can be obtained with conventional un-templated media growth. The templated growth technique is also a suitable additive technique for the fabrication of Bit Patterned Media, another potential next-generation technology wherein the magnetic bits are isolated patterned islands. Combining nanoimprint lithography with templated growth, we can generate a long range spatially ordered array of magnetic islands with no etching of the magnetic material.

  1. Time-Dependent and Light-Induced Fading in Victoreen Model 2600-80 Aluminum Oxide Thermoluminescence Dosemeters

    Science.gov (United States)

    1993-01-01

    2600-80 Aluminium Oxide Thermoluminescence Dosemeters ":"TIC,7 • :+ " 7-t-•CTE S , E 1P 1993 F’ t LEA l E J. H. Musk AFRRI TR93-6 Cleared for Public...SUBTITLE 5. FUNDING NUMBERS Time-Dependent and Light-Induced Fading in Victoreen0 Model 2600-80 Aluminium Oxide Thermoluminescence PE: QAXM...MODEL 2600-80 ALUMINIUM OXIDE THERMOLUMINESCENCE DOSEMETERS J. H. Musk Accesion For NTIS CRA&I DTIC TAB U.,announced D Justification ........ -.. By

  2. 17β-estradiol ameliorates light-induced retinal damage in Sprague-Dawley rats by reducing oxidative stress.

    Science.gov (United States)

    Wang, Shaolan; Wang, Baoying; Feng, Yan; Mo, Mingshu; Du, Fangying; Li, Hongbo; Yu, Xiaorui

    2015-01-01

    Oxidative stress is considered as a major cause of light-induced retinal neurodegeneration. The protective role of 17β-estradiol (βE2) in neurodegenerative disorders is well known, but its underlying mechanism remains unclear. Here, we utilized a light-induced retinal damage model to explore the mechanism by which βE2 exerts its neuroprotective effect. Adult male and female ovariectomized (OVX) rats were exposed to 8,000 lx white light for 12 h to induce retinal light damage. Electroretinogram (ERG) assays and hematoxylin and eosin (H&E) staining revealed that exposure to light for 12 h resulted in functional damage to the rat retina, histological changes, and retinal neuron loss. However, intravitreal injection (IVI) of βE2 significantly rescued this impaired retinal function in both female and male rats. Based on the level of malondialdehyde (MDA) production (a biomarker of oxidative stress), an increase in retinal oxidative stress followed light exposure, and βE2 administration reduced this light-induced oxidative stress. Quantitative reverse-transcriptase (qRT)-PCR indicated that the messenger RNA (mRNA) levels of the antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (Gpx) were downregulated in female OVX rats but were upregulated in male rats after light exposure, suggesting a gender difference in the regulation of these antioxidant enzyme genes in response to light. However, βE2 administration restored or enhanced the SOD and Gpx expression levels following light exposure. Although the catalase (CAT) expression level was insensitive to light stimulation, βE2 also increased the CAT gene expression level in both female OVX and male rats. Further examination indicated that the antioxidant proteins thioredoxin (Trx) and nuclear factor erythroid 2-related factor 2 (Nrf2) are also involved in βE2-mediated antioxidation and that the cytoprotective protein heme oxygenase-1 (HO-1) plays a key role in the endogenous defense mechanism

  3. Galerkin analysis of light-induced patterns in the chlorine dioxide-iodine-malonic acid reaction-diffusion system

    Science.gov (United States)

    Ghosh, Pushpita; Sen, Shrabani; Riaz, Syed Shahed; Ray, Deb Shankar

    2009-05-01

    The photosensitive chlorine dioxide-iodine-malonic acid reaction-diffusion system has been an experimental paradigm for the study of Turing pattern over the last several years. When subjected to illumination of varied intensity by visible light the patterns undergo changes from spots to stripes, vice versa, and their mixture. We carry out a nonlinear analysis of the underlying model in terms of a Galerkin scheme with finite number of modes to explore the nature of the stability and existence of various modes responsible for the type and crossover of the light-induced patterns.

  4. Light-induced immobilisation of biomolecules as an attractive alternative to microdroplet dispensing-based arraying technologies

    DEFF Research Database (Denmark)

    Crookshanks, Meg; Skovsen, Esben; Petersen, Maria Teresa Neves;

    2007-01-01

    The present work shows how UV ‘light-induced molecular immobilisation' (LIMI) of biomolecules onto thiol reactive surfaces can be used to make biosensors, without the need for traditional microdispensing technologies. Using ‘LIMI,' arrays of biomolecules can be created with a high degree...... to conventional array formats. The ultimate consequence of the LIMI is that it is possible to write complex protein patterns using bitmaps at high resolution onto substrates. Thus, LIMI of biomolecules provides a new technological platform for biomolecular immobilisation and the potential for replacing present...

  5. Light induces Fos expression via extracellular signal-regulated kinases 1/2 in melanopsin-expressing PC12 cells

    DEFF Research Database (Denmark)

    Moldrup, Marie-Louise Bülow; Georg, Birgitte; Falktoft, Birgitte;

    2010-01-01

    -regulated protein kinase 1/2 (ERK1/2) was found as pharmacological blockage of this kinase suppressed the light-induced Fos expression. Illumination increased the inositol phosphate turnover and induced phosphorylation of ERK1/2 and p38 but not the c-Jun N-terminal kinase. The Galpha(q/11) protein inhibitor YM......254890 attenuated these intracellular light responses. Our data strongly indicate that Galpha(q/11)-mediated ERK1/2 activation is essential for expression of Fos upon illumination of melanopsin-expressing PC12 cells....

  6. Cold Atom Physics Using Ultra-Thin Optical Fibers: Light-Induced Dipole Forces and Surface Interactions

    CERN Document Server

    Sagu'e, G; Meschede, D; Rauschenbeutel, A; Vetsch, E

    2007-01-01

    The strong evanescent field around ultra-thin unclad optical fibers bears a high potential for detecting, trapping, and manipulating cold atoms. Introducing such a fiber into a cold atom cloud, we investigate the interaction of a small number of cold Caesium atoms with the guided fiber mode and with the fiber surface. Using high resolution spectroscopy, we observe and analyze light-induced dipole forces, van der Waals interaction, and a significant enhancement of the spontaneous emission rate of the atoms. The latter can be assigned to the modification of the vacuum modes by the fiber.

  7. Theoretical Analysis of a Self-Replicator With Reduced Template Inhibition Based on an Informational Leaving Group.

    Science.gov (United States)

    Bigan, Erwan; Mattelaer, Henri-Philippe; Herdewijn, Piet

    2016-03-01

    The first non-enzymatic self-replicating systems, as proposed by von Kiedrowski (Angew Chem Int Ed Engl 25(10):932-935, 1986) and Orgel (Nature 327(6120):346-347, 1987), gave rise to the analytical background still used today to describe artificial replicators. What separates a self-replicating from an autocatalytic system is the ability to pass on structural information (Orgel, Nature 358(6383):203-209, 1992). Utilising molecular information, nucleic acids were the first choice as prototypical examples. But early self-replicators showed parabolic over exponential growth due to the strongly bound template duplex after template-directed ligation of substrates. We propose a self-replicating scheme with a weakly bound template duplex, using an informational leaving group. Such a scheme is inspired by the role of tRNA as leaving group and information carrier during protein synthesis, and is based on our previous experience with nucleotide chemistry. We analyse theoretically this scheme and compare it to the classical minimal replicator model. We show that for an example hexanucleotide template mirroring that is used by von Kiedrowski (Bioorganic chemistry frontiers, 1993) for the analysis of the classical minimal replicator, the proposed scheme is expected to result in higher template self-replication rate. The proposed self-replicating scheme based on an informational leaving group is expected to outperform the classical minimal replicator because of a weaker template duplex bonding, resulting in reduced template inhibition.

  8. Templating irreversible covalent macrocyclization by using anions.

    Science.gov (United States)

    Kataev, Evgeny A; Kolesnikov, Grigory V; Arnold, Rene; Lavrov, Herman V; Khrustalev, Victor N

    2013-03-11

    Inorganic anions were used as templates in the reaction between a diamine and an activated diacid to form macrocyclic amides. The reaction conditions were found to perform the macrocyclization sufficiently slow to observe a template effect. A number of analytical methods were used to clarify the reaction mechanisms and to show that the structure of the intermediate plays a decisive role in determining the product distribution. For the macrocyclization under kinetic control, it was shown that the amount of a template, the conformational rigidity of building blocks, and the anion affinities of reaction components and intermediates are important parameters that one should take into consideration to achieve high yields.

  9. Non-surfactant synthesis of mesoporous silica with dye as template

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A novel non-surfactant method was described to synthesize mesoporous silica using dye basic fuchsin as template. Chemical reactions were introduced into the formation of mesopores rather than the weak electrostatic or hydrogen-bonding interactions in the traditional surfactant routes. The reactant composition was found to be crucial to the pore structure of objective product. The formation mechanism of mesopore was also proved.

  10. Crystal structure of the nucleosome containing ultraviolet light-induced cyclobutane pyrimidine dimer.

    Science.gov (United States)

    Horikoshi, Naoki; Tachiwana, Hiroaki; Kagawa, Wataru; Osakabe, Akihisa; Matsumoto, Syota; Iwai, Shigenori; Sugasawa, Kaoru; Kurumizaka, Hitoshi

    2016-02-26

    The cyclobutane pyrimidine dimer (CPD) is induced in genomic DNA by ultraviolet (UV) light. In mammals, this photolesion is primarily induced within nucleosomal DNA, and repaired exclusively by the nucleotide excision repair (NER) pathway. However, the mechanism by which the CPD is accommodated within the nucleosome has remained unknown. We now report the crystal structure of a nucleosome containing CPDs. In the nucleosome, the CPD induces only limited local backbone distortion, and the affected bases are accommodated within the duplex. Interestingly, one of the affected thymine bases is located within 3.0 Å from the undamaged complementary adenine base, suggesting the formation of complementary hydrogen bonds in the nucleosome. We also found that UV-DDB, which binds the CPD at the initial stage of the NER pathway, also efficiently binds to the nucleosomal CPD. These results provide important structural and biochemical information for understanding how the CPD is accommodated and recognized in chromatin.

  11. Supramolecular ssDNA templated porphyrin and metalloporphyrin nanoassemblies with tunable helicity.

    Science.gov (United States)

    Sargsyan, Gevorg; Leonard, Brian M; Kubelka, Jan; Balaz, Milan

    2014-02-10

    Free-base and nickel porphyrin-diaminopurine conjugates were formed by hydrogen-bond directed assembly on single-stranded oligothymidine templates of different lengths into helical multiporphyrin nanoassemblies with highly modular structural and chiroptical properties. Large red-shifts of the Soret band in the UV/Vis spectroscopy confirmed strong electronic coupling among assembled porphyrin-diaminopurine units. Slow annealing rates yielded preferentially right-handed nanostructures, whereas fast annealing yielded left-handed nanostructures. Time-dependent DFT simulations of UV/Vis and CD spectra for model porphyrin clusters templated on the canonical B-DNA and its enantiomeric form, were employed to confirm the origin of observed chiroptical properties and to assign the helicity of porphyrin nanoassemblies. Molar CD and CD anisotropy g factors of dialyzed templated porphyrin nanoassemblies showed very high chiroptical anisotropy. The DNA-templated porphyrin nanoassemblies displayed high thermal and pH stability. The structure and handedness of all assemblies was preserved at temperatures up to +85 °C and pH between 3 and 12. High-resolution transition electron microscopy confirmed formation of DNA-templated nickel(II) porphyrin nanoassemblies and their self-assembly into helical fibrils with micrometer lengths.

  12. Dangling-bond defect in a-Si:H: Characterization of network and strain effects by first-principles calculation of the EPR parameters

    NARCIS (Netherlands)

    Pfanner, G.; Freysoldt, C.; Neugebauer, J.; Inam, F.; Drabold, D.; Jarolimek, K.; Zeman, M.

    2013-01-01

    The performance of hydrogenated amorphous silicon (a-Si:H) solar cells is severely affected by the light-induced formation of metastable defects in the material (Staebler-Wronski effect). The common notion is that the dangling-bond (db) defect, a threefold coordinated silicon atom, plays a key role

  13. Self-templated chemically stable hollow spherical covalent organic framework

    Science.gov (United States)

    Kandambeth, Sharath; Venkatesh, V.; Shinde, Digambar B.; Kumari, Sushma; Halder, Arjun; Verma, Sandeep; Banerjee, Rahul

    2015-04-01

    Covalent organic frameworks are a family of crystalline porous materials with promising applications. Although active research on the design and synthesis of covalent organic frameworks has been ongoing for almost a decade, the mechanisms of formation of covalent organic frameworks crystallites remain poorly understood. Here we report the synthesis of a hollow spherical covalent organic framework with mesoporous walls in a single-step template-free method. A detailed time-dependent study of hollow sphere formation reveals that an inside-out Ostwald ripening process is responsible for the hollow sphere formation. The synthesized covalent organic framework hollow spheres are highly porous (surface area ~1,500 m2 g-1), crystalline and chemically stable, due to the presence of strong intramolecular hydrogen bonding. These mesoporous hollow sphere covalent organic frameworks are used for a trypsin immobilization study, which shows an uptake of 15.5 μmol g-1 of trypsin.

  14. Template-Directed Ligation of Peptides to Oligonucleotides

    Science.gov (United States)

    Bruick, Richard K.; Dawson, Philip E.; Kent, Stephen BH; Usman, Nassim; Joyce, Gerald F.

    1996-01-01

    Synthetic oligonucleotides and peptides have enjoyed a wide range of applications in both biology and chemistry. As a consequence, oligonucleotide-peptide conjugates have received considerable attention, most notably in the development of antisense constructs with improved pharmacological properties. In addition, oligonucleotide-peptide conjugates have been used as molecular tags, in the assembly of supramolecular arrays and in the construction of encoded combinatorial libraries. To make these chimeric molecules more accessible for a broad range of investigations, we sought to develop a facile method for joining fully deprotected oligonucleotides and peptides through a stable amide bond linkage. Furthermore, we wished to make this ligation reaction addressable, enabling one to direct the ligation of specific oligonucleotide and peptide components.To confer specificity and accelerate the rate of the reaction, the ligation process was designed to be dependent on the presence of a complementary oligonucleotide template.

  15. Rev1, Rev3, or Rev7 siRNA Abolishes Ultraviolet Light-Induced Translesion Replication in HeLa Cells: A Comprehensive Study Using Alkaline Sucrose Density Gradient Sedimentation

    Directory of Open Access Journals (Sweden)

    Jun Takezawa

    2010-01-01

    Full Text Available When a replicative DNA polymerase stalls upon encountering a lesion on the template strand, it is relieved by other low-processivity polymerase(s, which insert nucleotide(s opposite the lesion, extend by a few nucleotides, and dissociate from the 3′-OH. The replicative polymerase then resumes DNA synthesis. This process, termed translesion replication (TLS or replicative bypass, may involve at least five different polymerases in mammals, although the participating polymerases and their roles have not been entirely characterized. Using siRNAs originally designed and an alkaline sucrose density gradient sedimentation technique, we verified the involvement of several polymerases in ultraviolet (UV light-induced TLS in HeLa cells. First, siRNAs to Rev3 or Rev7 largely abolished UV-TLS, suggesting that these 2 gene products, which comprise Polζ, play a main role in mutagenic TLS. Second, Rev1-targeted siRNA also abrogated UV-TLS, indicating that Rev1 is also indispensable to mutagenic TLS. Third, Polη-targeted siRNA also prevented TLS to a greater extent than our expectations. Forth, although siRNA to Polι had no detectable effect, that to Polκ delayed UV-TLS. To our knowledge, this is the first study reporting apparent evidence for the participation of Polκ in UV-TLS.

  16. Templated and template-free fabrication strategies for zero-dimensional hollow MOF superstructures.

    Science.gov (United States)

    Kim, Hyehyun; Lah, Myoung Soo

    2017-03-23

    Various fabrication strategies for hollow metal-organic framework (MOF) superstructures are reviewed and classified using various types of external templates and their properties. Hollow MOF superstructures have also been prepared without external templates, wherein unstable intermediates obtained during reactions convert to the final hollow MOF superstructures. Many hollow MOF superstructures have been fabricated using hard templates. After the core-shell core@MOF structure was prepared using a hard template, the core was selectively etched to generate a hollow MOF superstructure. Another approach for generating hollow superstructures is to use a solid reactant as a sacrificial template; this method requires no additional etching process. Soft templates such as discontinuous liquid/emulsion droplets and gas bubbles in a continuous soft phase have also been employed to prepare hollow MOF superstructures.

  17. Template for safety reports with descriptive example

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-12-01

    This report provides a template for future safety reports on long-term safety in support of important decisions and permit applications in connection with the construction of a deep repository system. The template aims at providing a uniform structure for describing long-term safety, after the repository has been closed and sealed. The availability of such a structure will simplify both preparation and review of the safety reports, and make it possible to follow how safety assessments are influenced by the progressively more detailed body of data that emerges. A separate section containing `descriptive examples` has been appended to the template. This section illustrates what the different chapters of the template should contain. 279 refs.

  18. Template Approach for Adaptive Learning Strategies

    NARCIS (Netherlands)

    Abbing, Jana; Koidl, Kevin

    2006-01-01

    Please, cite this publication as: Abbing, J. & Koidl, K. (2006). Template Approach for Adaptive Learning Strategies. Proceedings of Adaptive Hypermedia. June, Dublin, Ireland. Retrieved June 30th, 2006, from http://dspace.learningnetworks.org

  19. Performance Evaluation of Biometric Template Update

    CERN Document Server

    Giot, Romain; Dorizzi, Bernadette

    2012-01-01

    Template update allows to modify the biometric reference of a user while he uses the biometric system. With such kind of mechanism we expect the biometric system uses always an up to date representation of the user, by capturing his intra-class (temporary or permanent) variability. Although several studies exist in the literature, there is no commonly adopted evaluation scheme. This does not ease the comparison of the different systems of the literature. In this paper, we show that using different evaluation procedures can lead in different, and contradictory, interpretations of the results. We use a keystroke dynamics (which is a modality suffering of template ageing quickly) template update system on a dataset consisting of height different sessions to illustrate this point. Even if we do not answer to this problematic, it shows that it is necessary to normalize the template update evaluation procedures.

  20. Nanowires and nanostructures fabrication using template methods

    DEFF Research Database (Denmark)

    Mátéfi-Tempfli, Stefan; Mátéfi-Tempfli, M.; Vlad, A.;

    2009-01-01

    One of the great challenges of today is to find reliable techniques for the fabrication of nanomaterials and nanostructures. Methods based on template synthesis and on self organization are the most promising due to their easiness and low cost. This paper focuses on the electrochemical synthesis ...... of nanowires and nanostructures using nanoporous host materials such as supported anodic aluminum considering it as a key template for nanowires based devices. New ways are opened for applications by combining such template synthesis methods with nanolithographic techniques.......One of the great challenges of today is to find reliable techniques for the fabrication of nanomaterials and nanostructures. Methods based on template synthesis and on self organization are the most promising due to their easiness and low cost. This paper focuses on the electrochemical synthesis...

  1. Influence of light-induced conical intersection on the photodissociation dynamics of D2(+) starting from individual vibrational levels.

    Science.gov (United States)

    Halász, Gábor J; Csehi, András; Vibók, Ágnes; Cederbaum, Lorenz S

    2014-12-26

    Previous works have shown that dressing of diatomic molecules by standing or by running laser waves gives rise to the appearance of so-called light-induced conical intersections (LICIs). Because of the strong nonadiabatic couplings, the existence of such LICIs may significantly change the dynamical properties of a molecular system. In our former paper (J. Phys. Chem. A 2013, 117, 8528), the photodissociation dynamics of the D(2)(+) molecule were studied in the LICI framework starting the initial vibrational nuclear wave packet from the superposition of all the vibrational states initially produced by ionizing D(2). The present work complements our previous investigation by letting the initial nuclear wave packets start from different individual vibrational levels of D(2)(+), in particular, above the energy of the LICI. The kinetic energy release spectra, the total dissociation probabilities, and the angular distributions of the photofragments are calculated and discussed. An interesting phenomenon has been found in the spectra of the photofragments. Applying the light-induced adiabatic picture supported by LICI, explanations are given for the unexpected structure of the spectra.

  2. Influence of saliva-coating on the ultraviolet-light-induced photocatalytic bactericidal effects on modified titanium surfaces

    Science.gov (United States)

    Lee, Jeong-Eun; Park, So-Yoon; Chang, Young-Il; Lim, Young-Jun; Ahn, Sug-Joon

    2012-07-01

    The purpose of this study was to investigate the ultraviolet-light-induced photocatalytic bactericidal effects of titanium surfaces on Streptococcus sanguinis in the presence of saliva-coating. Three different titanium disks were prepared: machined (MA), heat-treated (HT), and anodized surfaces (AO). Each disk was incubated with whole saliva or phosphate-buffered saline for 2 h. Antibacterial tests were performed by incubating a S. sanguinis suspension with each disk for 90 or 180 min under ultraviolet (UV) illumination. The viable counts of bacteria were enumerated from the cell suspension and the UV-light-induced photocatalytic bactericidal effects were determined by the bacterial survival rate. Without saliva-coating, AO disks exhibited significantly decreased bacterial survival rates compared to MA disks. The bacterial survival rates of the HT disks were intermediate between MA and AO in the absence of saliva-coating. However, saliva-coating significantly increased bacterial survival rates in all surface types. There was no significant difference in bacterial survival rates among the three surface types after saliva-coating. This study suggests that Ti-based antibacterial implant materials using TiO2 photocatalyst may have a limitation for intraoral use.

  3. Research on critical technology of micro/nano bioparticles manipulation platform based on light-induced dielectrophoresis

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    On the basis of the research on the status and problems of micro/nano bio-particles manipulation using dielectrophoresis, the theoretical basis and the model simulation of micro/nano bio-particles manipu-lation using light-induced dielectrophoresis were discussed. The space distribution of electric field and dielectrophoresis forces in different heights were also obtained. On this basis, the core component of the micro manipulation system, that is, photoconductive layer of the chip, was completed in the mate-rial selection, fabricating process and performance analysis testing. Then the voltage drop of the sus-pension and the effective voltage frequency spectrum were obtained. Finally, by combining the machine vision detection with real-time tracking system, the micro/nano bio-particles manipulation platform based on the light-induced dielectrophoreisis was established, and then the manipulations for micro/nano bio-particles, such as quick collection, transport, separation, were implemented. This provided a basis for rapid, accurate, and low-cost detection of serious diseases based on the micro-fluidic biochip and early diagnosis.

  4. Protective Effect of Proanthocyanidins from Sea Buckthorn (Hippophae Rhamnoides L.) Seed against Visible Light-Induced Retinal Degeneration in Vivo.

    Science.gov (United States)

    Wang, Yong; Zhao, Liang; Huo, Yazhen; Zhou, Feng; Wu, Wei; Lu, Feng; Yang, Xue; Guo, Xiaoxuan; Chen, Peng; Deng, Qianchun; Ji, Baoping

    2016-05-02

    Dietary proanthocyanidins (PACs) as health-protective agents have become an important area of human nutrition research because of their potent bioactivities. We investigated the retinoprotective effects of PACs from sea buckthorn (Hippophae rhamnoides L.) seed against visible light-induced retinal degeneration in vivo. Pigmented rabbits were orally administered sea buckthorn seed PACs (50 and 100 mg/kg/day) for 14 consecutive days of pre-illumination and seven consecutive days of post-illumination. Retinal function was quantified via electroretinography 7 days after light exposure. Retinal damage was evaluated by measuring the thickness of the full-thickness retina and outer nuclear layer 7 days after light exposure. Sea buckthorn seed PACs significantly attenuated the destruction of electroretinograms and maintained the retinal structure. Increased retinal photooxidative damage was expressed by the depletion of glutathione peroxidase and catalase activities, the decrease of total antioxidant capacity level and the increase of malondialdehyde level. Light exposure induced a significant increase of inflammatory cytokines (IL-1β, TNF-α and IL-6) and angiogenesis (VEGF) levels in retina. Light exposure upregulated the expression of pro-apoptotic proteins Bax and caspase-3 and downregulated the expression of anti-apoptotic protein Bcl-2. However, sea buckthorn seed PACs ameliorated these changes induced by light exposure. Sea buckthorn seed PACs mediated the protective effect against light-induced retinal degeneration via antioxidant, anti-inflammatory and antiapoptotic mechanisms.

  5. Visible light induced electron transfer process over nitrogen doped TiO(2) nanocrystals prepared by oxidation of titanium nitride.

    Science.gov (United States)

    Wu, Zhongbiao; Dong, Fan; Zhao, Weirong; Guo, Sen

    2008-08-30

    Nitrogen doped TiO(2) nanocrystals with anatase and rutile mixed phases were prepared by incomplete oxidation of titanium nitride at different temperatures. The as-prepared samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), core level X-ray photoelectron spectroscopy (CL XPS), valence band X-ray photoelectron spectroscopy (VB XPS), UV-vis diffuse reflectance spectra (UV-vis DRS), and visible light excited photoluminescence (PL). The photocatalytic activity was evaluated for photocatalytic degradation of toluene in gas phase under visible light irradiation. The visible light absorption and photoactivities of these nitrogen doped TiO(2) nanocrystals can be clearly attributed to the change of the additional electronic (N(-)) states above the valence band of TiO(2) modified by N dopant as revealed by the VB XPS and visible light induced PL. A band gap structure model was established to explain the electron transfer process over nitrogen doped TiO(2) nanocrystals under visible light irradiation, which was consistent with the previous theoretical and experimental results. This model can also be applied to understand visible light induced photocatalysis over other nonmetal doped TiO(2).

  6. Protective Effect of Proanthocyanidins from Sea Buckthorn (Hippophae Rhamnoides L. Seed against Visible Light-Induced Retinal Degeneration in Vivo

    Directory of Open Access Journals (Sweden)

    Yong Wang

    2016-05-01

    Full Text Available Dietary proanthocyanidins (PACs as health-protective agents have become an important area of human nutrition research because of their potent bioactivities. We investigated the retinoprotective effects of PACs from sea buckthorn (Hippophae rhamnoides L. seed against visible light-induced retinal degeneration in vivo. Pigmented rabbits were orally administered sea buckthorn seed PACs (50 and 100 mg/kg/day for 14 consecutive days of pre-illumination and seven consecutive days of post-illumination. Retinal function was quantified via electroretinography 7 days after light exposure. Retinal damage was evaluated by measuring the thickness of the full-thickness retina and outer nuclear layer 7 days after light exposure. Sea buckthorn seed PACs significantly attenuated the destruction of electroretinograms and maintained the retinal structure. Increased retinal photooxidative damage was expressed by the depletion of glutathione peroxidase and catalase activities, the decrease of total antioxidant capacity level and the increase of malondialdehyde level. Light exposure induced a significant increase of inflammatory cytokines (IL-1β, TNF-α and IL-6 and angiogenesis (VEGF levels in retina. Light exposure upregulated the expression of pro-apoptotic proteins Bax and caspase-3 and downregulated the expression of anti-apoptotic protein Bcl-2. However, sea buckthorn seed PACs ameliorated these changes induced by light exposure. Sea buckthorn seed PACs mediated the protective effect against light-induced retinal degeneration via antioxidant, anti-inflammatory and antiapoptotic mechanisms.

  7. Light-induced retinal injury enhanced neurotrophins secretion and neurotrophic effect of mesenchymal stem cells in vitro

    Directory of Open Access Journals (Sweden)

    Wei Xu

    2013-04-01

    Full Text Available PURPOSE: To investigate neurotrophins expression and neurotrophic effect change in mesenchymal stem cells (MSCs under different types of stimulation. METHODS: Rats were exposed in 10,000 lux white light to develop light-induced retinal injury. Supernatants of homogenized retina (SHR, either from normal or light-injured retina, were used to stimulate MSCs. Quantitative real time for polymerase chain reaction (RT-PCR and enzyme-linked immunosorbent assay (ELISA were conducted for analysis the expression change in basic fibroblast growth factor (bFGF, brain-derived neurotrophic factor (BDNF and ciliary neurotrophic factor (CNTF in MSCs after stimulation. Conditioned medium from SHR-stimulated MSCs and control MSCs were collected for evaluation their effect on retinal explants. RESULTS: Supernatants of homogenized retina from light-injured rats significantly promoted neurotrophins secretion from MSCs (p<0.01. Conditioned medium from mesenchymal stem cells stimulated by light-injured SHR significantly reduced DNA fragmentation (p<0.01, up-regulated bcl-2 (p<0.01 and down-regulated bax (p<0.01 in retinal explants, displaying enhanced protective effect. CONCLUSIONS: Light-induced retinal injury is able to enhance neurotrophins secretion from mesenchymal stem cells and promote the neurotrophic effect of mesenchymal stem cells.

  8. Laminin-521 Promotes Rat Bone Marrow Mesenchymal Stem Cell Sheet Formation on Light-Induced Cell Sheet Technology

    Directory of Open Access Journals (Sweden)

    Zhiwei Jiang

    2017-01-01

    Full Text Available Rat bone marrow mesenchymal stem cell sheets (rBMSC sheets are attractive for cell-based tissue engineering. However, methods of culturing rBMSC sheets are critically limited. In order to obtain intact rBMSC sheets, a light-induced cell sheet method was used in this study. TiO2 nanodot films were coated with (TL or without (TN laminin-521. We investigated the effects of laminin-521 on rBMSCs during cell sheet culturing. The fabricated rBMSC sheets were subsequently assessed to study cell sheet viability, reattachment ability, cell sheet thickness, collagen type I deposition, and multilineage potential. The results showed that laminin-521 could promote the formation of rBMSC sheets with good viability under hyperconfluent conditions. Cell sheet thickness increased from an initial 26.7 ± 1.5 μm (day 5 up to 47.7 ± 3.0 μm (day 10. Moreover, rBMSC sheets maintained their potential of osteogenic, adipogenic, and chondrogenic differentiation. This study provides a new strategy to obtain rBMSC sheets using light-induced cell sheet technology.

  9. Dynamical decoherence of the light induced interlayer coupling in YB a2C u3O6 +δ

    Science.gov (United States)

    Hunt, C. R.; Nicoletti, D.; Kaiser, S.; Pröpper, D.; Loew, T.; Porras, J.; Keimer, B.; Cavalleri, A.

    2016-12-01

    Optical excitation of apical oxygen vibrations in YB a2C u3O6 +δ has been shown to enhance its c axis superconducting-phase rigidity, as evidenced by a transient blueshift of the equilibrium interbilayer Josephson plasma resonance. Surprisingly, a transient c axis plasma mode could also be induced above Tc by the same apical oxygen excitation, suggesting light activated superfluid tunneling throughout the pseudogap phase of YB a2C u3O6 +δ . However, despite the similarities between the transient plasma mode above Tc and the equilibrium Josephson plasmon, alternative explanations involving high-mobility quasiparticle transport should be considered. Here, we report an extensive study of the relaxation of the light induced plasmon into the equilibrium incoherent phase. These new experiments allow for a critical assessment of the nature of this mode. We determine that the transient plasma relaxes through a collapse of its coherence length rather than its carrier (or superfluid) density. These observations are not easily reconciled with quasiparticle interlayer transport and rather support transient superfluid tunneling as the origin of the light induced interlayer coupling in YB a2C u3O6 +δ .

  10. Macroporous polymer foams by hydrocarbon templating

    OpenAIRE

    Shastri, Venkatram Prasad; Martin, Ivan; Langer, Robert

    2000-01-01

    Porous polymeric media (polymer foams) are utilized in a wide range of applications, such as thermal and mechanical insulators, solid supports for catalysis, and medical devices. A process for the production of polymer foams has been developed. This process, which is applicable to a wide range of polymers, uses a hydrocarbon particulate phase as a template for the precipitation of the polymer phase and subsequent pore formation. The use of a hydrocarbon template allows for enhanced control ov...

  11. Lipid bilayers on nano-templates

    Science.gov (United States)

    Noy, Aleksandr; Artyukhin, Alexander B.; Bakajin, Olgica; Stoeve, Pieter

    2009-08-04

    A lipid bilayer on a nano-template comprising a nanotube or nanowire and a lipid bilayer around the nanotube or nanowire. One embodiment provides a method of fabricating a lipid bilayer on a nano-template comprising the steps of providing a nanotube or nanowire and forming a lipid bilayer around the polymer cushion. One embodiment provides a protein pore in the lipid bilayer. In one embodiment the protein pore is sensitive to specific agents

  12. Scalable, Fast Cloud Computing with Execution Templates

    OpenAIRE

    Mashayekhi, Omid; Qu, Hang; Shah, Chinmayee; Levis, Philip

    2016-01-01

    Large scale cloud data analytics applications are often CPU bound. Most of these cycles are wasted: benchmarks written in C++ run 10-51 times faster than frameworks such as Naiad and Spark. However, calling faster implementations from those frameworks only sees moderate (3-5x) speedups because their control planes cannot schedule work fast enough. This paper presents execution templates, a control plane abstraction for CPU-bound cloud applications, such as machine learning. Execution template...

  13. Cross Shear Roll Bonding

    DEFF Research Database (Denmark)

    Bay, Niels; Bjerregaard, Henrik; Petersen, Søren. B;

    1994-01-01

    The present paper describes an investigation of roll bonding an AlZn alloy to mild steel. Application of cross shear roll bonding, where the two equal sized rolls run with different peripheral speed, is shown to give better bond strength than conventional roll bonding. Improvements of up to 20......-23% in bond strength are found and full bond strength is obtained at a reduction of 50% whereas 65% is required in case of conventional roll bonding. Pseudo cross shear roll bonding, where the cross shear effect is obtained by running two equal sized rolls with different speed, gives the same results....

  14. How Langmuir-Blodgett trilayers act as templates for directed self-assembly of nanoparticles

    Science.gov (United States)

    Mukherjee, Smita; Datta, Alokmay; Biswas, Nupur; Giglia, Angelo; Nannarone, Stefano

    2014-04-01

    Atomic force microscopy (AFM) shows that Langmuir-Blodgett (LB) deposition of dissimilar metal stearates (MSt, M = Co, Zn, Cd) on templates of Co-stearate (Co-T) and Cd-stearate (Cd-T) results in self-assembly of MSts into nanocrystalline grains having clear and consistent morphological habits. The grains are better formed and well separated on Cd-T than on Co-T. Fourier transform infrared spectroscopy (FTIR) results show that the headgroup coordination of the overlayer is tuned by the coordination of the Cd-T template and remains unaffected by that of the Co-T template. They also indicate co-existence of a different kind of headgroup structure that is close to the undissociated fatty acid headgroup but differing more in the two types of carbon-oxygen bonds, suggesting an inter-headgroup bonding such as hydrogen bond that may exist on a nanocrystal surface. Results of synchrotron x-ray diffraction at C K-edge, of ZnSt on Cd-T (ZnSt/Cd-T) and Co-T (ZnSt/Co-T), point to a non-closed packed structure for ZnSt/Cd-T and a closed-packed structure for ZnSt/Co-T, with significant superlattice order in the former. The presence of crystalline phases of ZnSt in the nanometer scale, on LB templates, in contrast to the the presence of lamellar phase in bulk ZnSt, is attributed to the the presence of unidentate metal-carboxylate coordination in the former and absence of it in the latter, creating different gradients of dipolar forces at template overlayer interface. Relative strength of this long-range force over short-range intermolecular forces in the templates qualitatively explains better crystallinity and higher ordering in ZnSt/Cd-T compared to ZnSt/Co-T. We propose that the role of dipole moment gradient between template and overlayer in tuning of these metal-organic nanoparticles may be somewhat similar to structural and optical tunability of semiconductor nanocrystals by thermal and self-equilibrium strain.

  15. Multi-template polymerase chain reaction

    Directory of Open Access Journals (Sweden)

    Elena Kalle

    2014-12-01

    Full Text Available PCR is a formidable and potent technology that serves as an indispensable tool in a wide range of biological disciplines. However, due to the ease of use and often lack of rigorous standards many PCR applications can lead to highly variable, inaccurate, and ultimately meaningless results. Thus, rigorous method validation must precede its broad adoption to any new application. Multi-template samples possess particular features, which make their PCR analysis prone to artifacts and biases: multiple homologous templates present in copy numbers that vary within several orders of magnitude. Such conditions are a breeding ground for chimeras and heteroduplexes. Differences in template amplification efficiencies and template competition for reaction compounds undermine correct preservation of the original template ratio. In addition, the presence of inhibitors aggravates all of the above-mentioned problems. Inhibitors might also have ambivalent effects on the different templates within the same sample. Yet, no standard approaches exist for monitoring inhibitory effects in multitemplate PCR, which is crucial for establishing compatibility between samples.

  16. Infrared light-induced protein crystallization. Structuring of protein interfacial water and periodic self-assembly

    Science.gov (United States)

    Kowacz, Magdalena; Marchel, Mateusz; Juknaité, Lina; Esperança, José M. S. S.; Romão, Maria João; Carvalho, Ana Luísa; Rebelo, Luís Paulo N.

    2017-01-01

    We show that a physical trigger, a non-ionizing infrared (IR) radiation at wavelengths strongly absorbed by liquid water, can be used to induce and kinetically control protein (periodic) self-assembly in solution. This phenomenon is explained by considering the effect of IR light on the structuring of protein interfacial water. Our results indicate that the IR radiation can promote enhanced mutual correlations of water molecules in the protein hydration shell. We report on the radiation-induced increase in both the strength and cooperativeness of H-bonds. The presence of a structured dipolar hydration layer can lead to attractive interactions between like-charged biomacromolecules in solution (and crystal nucleation events). Furthermore, our study suggests that enveloping the protein within a layer of structured solvent (an effect enhanced by IR light) can prevent the protein non-specific aggregation favoring periodic self-assembly. Recognizing the ability to affect protein-water interactions by means of IR radiation may have important implications for biological and bio-inspired systems.

  17. Wire bonding in microelectronics

    CERN Document Server

    Harman, George G

    2010-01-01

    Wire Bonding in Microelectronics, Third Edition, has been thoroughly revised to help you meet the challenges of today's small-scale and fine-pitch microelectronics. This authoritative guide covers every aspect of designing, manufacturing, and evaluating wire bonds engineered with cutting-edge techniques. In addition to gaining a full grasp of bonding technology, you'll learn how to create reliable bonds at exceedingly high yields, test wire bonds, solve common bonding problems, implement molecular cleaning methods, and much more. Coverage includes: Ultrasonic bonding systems and technologies, including high-frequency systems Bonding wire metallurgy and characteristics, including copper wire Wire bond testing Gold-aluminum intermetallic compounds and other interface reactions Gold and nickel-based bond pad plating materials and problems Cleaning to improve bondability and reliability Mechanical problems in wire bonding High-yield, fine-pitch, specialized-looping, soft-substrate, and extreme-temperature wire bo...

  18. Simplification of Template-free Method to Prepare Polyaniline Nanotubes

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    1 Introduction Conducting polymer nanostructures (e.g.nanotubes or nanofibers) have received considerable attention owing their unique properties and promising applications in technology and nano-devices[1]. Conducting polymer nanostructures can be generally synthesized through "hard" and "soft" template method.Usually an external hard template in a "hard-template" method is required and the post-treatment of removing template is rather tedious."Soft-template" method is advantageous of omitting external...

  19. Fabrication of Micrometer- and Nanometer-Scale Polymer Structures by Visible Light Induced Dielectrophoresis (DEP Force

    Directory of Open Access Journals (Sweden)

    Wen J. Li

    2011-12-01

    Full Text Available We report in this paper a novel, inexpensive and flexible method for fabricating micrometer- and nanometer-scale three-dimensional (3D polymer structures using visible light sources instead of ultra-violet (UV light sources or lasers. This method also does not require the conventional micro-photolithographic technique (i.e., photolithographic masks for patterning and fabricating polymer structures such as hydrogels. The major materials and methods required for this novel fabrication technology are: (1 any cross-linked network of photoactive polymers (examples of fabricated poly(ethylene glycol (PEG-diacrylate hydrogel structures are shown in this paper; (2 an Optically-induced Dielectrophoresis (ODEP System which includes an “ODEP chip” (i.e., any chip that changes its surface conductivity when exposed to visible light, an optical microscope, a projector, and a computer; and (3 an animator software hosted on a computer that can generate virtual or dynamic patterns which can be projected onto the “ODEP chip” through the use of a projector and a condenser lens. Essentially, by placing a photosensitive polymer solution inside the microfluidic platform formed by the “ODEP chip” bonded to another substrate, and applying an alternating current (a.c. electrical potential across the polymer solution (typically ~20 Vp-p at 10 kHz, solid polymer micro/nano structures can then be formed on the “ODEP chip” surface when visible-light is projected onto the chip. The 2D lateral geometry (x and y dimensions and the thickness (height of the micro/nano structures are dictated by the image geometry of the visible light projected onto the “ODEP chip” and also the time duration of projection. Typically, after an image projection with intensity ranging from ~0.2 to 0.4 mW/cm2 for 10 s, ~200 nm high structures can be formed. In our current system, the thickness of these polymer structures can be controlled to form from ~200 nanometers to ~3

  20. Visible light induced TiO2 pillared MMT photocatalyst coupling-doped with S and N

    Institute of Scientific and Technical Information of China (English)

    ZHOU An-ning; CHEN You-mei; YU Zhan-jiang

    2008-01-01

    Visible light induced titanium dioxide (TiO2) pillared montmorillonite clay (MMT)photocatalyst coupling-doped with S and N elements was prepared by the two-step ad-sorption method. The photocatalyst was characterized by X-ray photoelectron spectros-copy (XPS) and ultraviolet-visible (UV-vis) absorption spectroscopy. The photocatalysic ef-ficacy of the prepared photocatalyst for degrading gaseous formaldehyde was evaluatedunder visible light irradiation. The degrading rate of gaseous formaldehyde is nearly 85%in 300 min visible light irradiation. The results demonstrate that the much higher visiblelight photocatalytic activity of the photocatalyst is due to the synergistic effects of coupling-doping of S and N elements to TiO2, extensive specific surface area of MMT and quantumsized efficacy between layers of MMT.

  1. Reaction site and mechanism in the UV or visible light induced TiO2 photodegradation of Orange G

    Institute of Scientific and Technical Information of China (English)

    YANG Shi-ying; LOU Li-ping; WU Xiao-na; CHEN Ying-xu

    2006-01-01

    For TiO2 heterogeneous reaction, the reaction site and the detailed mechanism are interesting and controversy topics. In this paper, effects of surface fluorination of TiO2 on the photocatalytic degradation of an azo dye, Orange G(OG) under UV or visible light irradiation were investigated, and the possible reaction site and mechanism were elucidated. The adsorption of OG on TiO2 was nearly inhibited by fluoride but its UV light induced photodegradation rate was greatly increased by a factor of about 2.7, which was due to the more generated free hydroxyl radicals. It supported the views that fluoride could desorb the oxidant species from surface and that the reaction sites could move to the bulk solution. In TiO2/Vis system, the observed inhibition effects of fluorination could be interpreted by the competitive adsorption, which provided additional evidences that the visible light sensitized photodegradation of dye pollutants on the catalyst surface.

  2. Molecular-scale dynamics of light-induced spin cross-over in a two-dimensional layer

    Science.gov (United States)

    Bairagi, Kaushik; Iasco, Olga; Bellec, Amandine; Kartsev, Alexey; Li, Dongzhe; Lagoute, Jérôme; Chacon, Cyril; Girard, Yann; Rousset, Sylvie; Miserque, Frédéric; Dappe, Yannick J; Smogunov, Alexander; Barreteau, Cyrille; Boillot, Marie-Laure; Mallah, Talal; Repain, Vincent

    2016-01-01

    Spin cross-over molecules show the unique ability to switch between two spin states when submitted to external stimuli such as temperature, light or voltage. If controlled at the molecular scale, such switches would be of great interest for the development of genuine molecular devices in spintronics, sensing and for nanomechanics. Unfortunately, up to now, little is known on the behaviour of spin cross-over molecules organized in two dimensions and their ability to show cooperative transformation. Here we demonstrate that a combination of scanning tunnelling microscopy measurements and ab initio calculations allows discriminating unambiguously between both states by local vibrational spectroscopy. We also show that a single layer of spin cross-over molecules in contact with a metallic surface displays light-induced collective processes between two ordered mixed spin-state phases with two distinct timescale dynamics. These results open a way to molecular scale control of two-dimensional spin cross-over layers. PMID:27425776

  3. Ultrafast light induced unusually broad transient absorption in the sub-bandgap region of GeSe2 thin film

    Science.gov (United States)

    Barik, A. R.; Bapna, Mukund; Drabold, D. A.; Adarsh, K. V.

    2014-01-01

    In this paper, we show for the first time that ultrafast light illumination can induce an unusually broad transient optical absorption (TA), spanning of ~ 200 nm in the sub-bandgap region of chalcogenide GeSe2 thin films, which we interpret as being a manifestation of creation and annihilation of light induced defects. Further, TA in ultrashort time scales show a maximum at longer wavelength, however blue shifts as time evolves, which provides the first direct evidence of the multiple decay mechanisms of these defects. Detailed global analysis of the kinetic data clearly demonstrates that two and three decay constants are required to quantitatively model the experimental data at ps and ns respectively.

  4. Engineering light-inducible nuclear localization signals for precise spatiotemporal control of protein dynamics in living cells.

    Science.gov (United States)

    Niopek, Dominik; Benzinger, Dirk; Roensch, Julia; Draebing, Thomas; Wehler, Pierre; Eils, Roland; Di Ventura, Barbara

    2014-07-14

    The function of many eukaryotic proteins is regulated by highly dynamic changes in their nucleocytoplasmic distribution. The ability to precisely and reversibly control nuclear translocation would, therefore, allow dissecting and engineering cellular networks. Here we develop a genetically encoded, light-inducible nuclear localization signal (LINuS) based on the LOV2 domain of Avena sativa phototropin 1. LINuS is a small, versatile tag, customizable for different proteins and cell types. LINuS-mediated nuclear import is fast and reversible, and can be tuned at different levels, for instance, by introducing mutations that alter AsLOV2 domain photo-caging properties or by selecting nuclear localization signals (NLSs) of various strengths. We demonstrate the utility of LINuS in mammalian cells by controlling gene expression and entry into mitosis with blue light.

  5. Synthesis of RNA oligomers on heterogeneous templates

    Science.gov (United States)

    Ertem, G.; Ferris, J. P.

    1996-01-01

    The concept of an RNA world in the chemical origin of life is appealing, as nucleic acids are capable of both information storage and acting as templates that catalyse the synthesis of complementary molecules. Template-directed synthesis has been demonstrated for homogeneous oligonucleotides that, like natural nucleic acids, have 3',5' linkages between the nucleotide monomers. But it seems likely that prebiotic routes to RNA-like molecules would have produced heterogeneous molecules with various kinds of phosphodiester linkages and both linear and cyclic nucleotide chains. Here we show that such heterogeneity need be no obstacle to the templating of complementary molecules. Specifically, we show that heterogeneous oligocytidylates, formed by the montmorillonite clay-catalysed condensation of actuated monomers, can serve as templates for the synthesis of oligoguanylates. Furthermore, we show that oligocytidylates that are exclusively 2',5'-linked can also direct synthesis of oligoguanylates. Such heterogeneous templating reactions could have increased the diversity of the pool of protonucleic acids from which life ultimately emerged.

  6. Automated Template Quantification for DNA Sequencing Facilities

    Science.gov (United States)

    Ivanetich, Kathryn M.; Yan, Wilson; Wunderlich, Kathleen M.; Weston, Jennifer; Walkup, Ward G.; Simeon, Christian

    2005-01-01

    The quantification of plasmid DNA by the PicoGreen dye binding assay has been automated, and the effect of quantification of user-submitted templates on DNA sequence quality in a core laboratory has been assessed. The protocol pipets, mixes and reads standards, blanks and up to 88 unknowns, generates a standard curve, and calculates template concentrations. For pUC19 replicates at five concentrations, coefficients of variance were 0.1, and percent errors were from 1% to 7% (n = 198). Standard curves with pUC19 DNA were nonlinear over the 1 to 1733 ng/μL concentration range required to assay the majority (98.7%) of user-submitted templates. Over 35,000 templates have been quantified using the protocol. For 1350 user-submitted plasmids, 87% deviated by ≥ 20% from the requested concentration (500 ng/μL). Based on data from 418 sequencing reactions, quantification of user-submitted templates was shown to significantly improve DNA sequence quality. The protocol is applicable to all types of double-stranded DNA, is unaffected by primer (1 pmol/μL), and is user modifiable. The protocol takes 30 min, saves 1 h of technical time, and costs approximately $0.20 per unknown. PMID:16461949

  7. In-vivo quantification of natural incipient caries lesions using the quantitative light-induced fluoroscence method: a reproducibility study

    Science.gov (United States)

    Tranaeus, Sofia; Shi, Xie-Qi; Trollsas, Karin; Lindgren, Lars-Erik; Angmar-Mansson, Birgit

    2000-03-01

    A new method for detection and quantification of natural incipient caries lesions, the Quantitative Light-induced Fluorescence method (QLF), has recently been developed. The aim of this study was to test the repeatability and reproducibility of the analytical part of the method. In vivo captured images (CCD-video camera, Panasonic WV-KS 152, with an argon ion laser as light source) of 15 different incipient caries lesions on smooth surfaces were analyzed by three analysts. The images were analyzed three times in a randomized order, twice for the first reconstructed area (P1A1 and P1A2), and then once for a second one (P2A1). Three parameters were measured, lesion area (mm2), average change in fluorescence (%), and maximum change in fluorescence (%) in the lesion. Repeated measures ANOVA were used to calculate the intra-, and inter-examiner reliability. Intra-examiner reliability for all three analysts showed an intra-class correlation coefficient, R, between 0.93 and 0.99 (for the analyses with the first patch, P1A1 and P1A2, as well as between the first and the second patch, P1A1 and P2A1). Inter-examiner reliability showed an inter-class correlation coefficient, R, between 0.95 and 0.99 (for analyses P1A1, P1A2 and P2A1). It was concluded that the Quantitative Light- induced fluorescence method showed excellent repeatability and reproducibility concerning the analytical part of the method.

  8. Vertex finding with deformable templates at LHC

    Energy Technology Data Exchange (ETDEWEB)

    Stepanov, N. [European Organization for Nuclear Research, Geneva (Switzerland); Khanov, A. [European Organization for Nuclear Research, Geneva (Switzerland)

    1997-04-11

    We present a novel vertex finding technique. The task is formulated as a discrete-continuous optimisation problem in a way similar to the deformable templates approach for the track finding. Unlike the track finding problem, ``elastic hedgehogs`` rather than elastic arms are used as deformable templates. They are initialised by a set of procedures which provide zero level approximation for vertex positions and track parameters at the vertex point. The algorithm was evaluated using the simulated events for the LHC CMS detector and demonstrated good performance. (orig.).

  9. Microwave assisted template synthesis of silver nanoparticles

    Indian Academy of Sciences (India)

    K J Sreeram; M Nidhin; B U Nair

    2008-12-01

    Easier, less time consuming, green processes, which yield silver nanoparticles of uniform size, shape and morphology are of interest. Various methods for synthesis, such as conventional temperature assisted process, controlled reaction at elevated temperatures, and microwave assisted process have been evaluated for the kind of silver nanoparticles synthesized. Starch has been employed as a template and reducing agent. Electron microscopy, photon correlation spectroscopy and surface plasmon resonance have been employed to characterize the silver nanoparticles synthesized. Compared to conventional methods, microwave assisted synthesis was faster and provided particles with an average particle size of 12 nm. Further, the starch functions as template, preventing the aggregation of silver nanoparticles.

  10. Preparation of porous lanthanum phosphate with templates

    Energy Technology Data Exchange (ETDEWEB)

    Onoda, Hiroaki, E-mail: onoda@kpu.ac.jp [Department of Informatics and Environmental Sciences, Faculty of Life and Environmental Sciences, Kyoto Prefectural University, 1-5, Shimogamo Nakaragi-cyo, Sakyo-ku, Kyoto 606-8522 (Japan); Ishima, Yuya [Department of Applied Chemistry, Faculty of Life Sciences, Ritsumeikan University, 1-1-1, Nojihigashi, Kusatsu, Shiga 525-8577 (Japan); Takenaka, Atsushi [Department of Materials Science, Yonago National College of Technology, 4448, Hikona-cho, Yonago, Tottori 683-8502 (Japan); Tanaka, Isao [Department of Materials Science and Engineering, Faculty of Engineering, Kyoto University, Yoshida-Honmachi, Sakyo-ku, Kyoto 606-8501 (Japan)

    2009-08-05

    Malonic acid, propionic acid, glycine, n-butylamine, and urea were added to the preparation of lanthanum phosphate from lanthanum nitrate and phosphoric acid solutions. All additives were taken into lanthanum phosphate particles. The additives that have a basic site were easy to contain in precipitates. The addition of templates improved the specific surface area of lanthanum phosphate. The amount of pore, with radius smaller than 4 nm, increased with the addition of templates. The remained additives had influence on the acidic properties of lanthanum phosphate.

  11. Preparation of Three-Dimensional Photonic Crystals of Zirconia by Electrodeposition in a Colloidal Crystals Template

    Directory of Open Access Journals (Sweden)

    Lei Pan

    2016-07-01

    Full Text Available Three-dimensional photonic crystals of zirconia were prepared by electrodeposition in a colloidal crystals template following calcination at 500 °C. Scanning electron microscopy, thermogravimetric analysis, X-ray diffraction, and reflectance spectroscopy were employed to characterize the photonic crystals of zirconia. It was found that hydrated zirconium ions could penetrate the colloidal crystals template and reach the substrate easily by electrodeposition, which resulted in stronger bonding between the substrate and the as-deposited membrane. Moreover, the electrodeposited membrane had low water content, leading to a low amount of shrinkage during calcination. Both these properties could suppress detachment from the substrate upon removal of the colloidal crystals template. Therefore, the three-dimensional photonic crystals of zirconia synthesized in this study exhibited very good preservation of the ordered structures of the colloidal crystals template with a high density. A peak of reflection higher than 70% was formed in the reflectance spectrum because of the strong diffraction of the ordered structures.

  12. The biogeochemical cycle of the adsorbed template. II - Selective adsorption of mononucleotides on adsorbed polynucleotide templates

    Science.gov (United States)

    Lazard, Daniel; Lahav, Noam; Orenberg, James B.

    1988-01-01

    Experimental results are presented for the verification of the specific interaction step of the 'adsorbed template' biogeochemical cycle, a simple model for a primitive prebiotic replication system. The experimental system consisted of gypsum as the mineral to which an oligonucleotide template attaches (Poly-C or Poly-U) and (5-prime)-AMP, (5-prime)-GMP, (5-prime)-CMP and (5-prime)-UMP as the interacting biomonomers. When Poly-C or Poly-U were used as adsorbed templates, (5-prime)-GMP and (5-prime)-AMP, respectively, were observed to be the most strongly adsorbed species.

  13. Template Syntheses, Crystal Structures and Supramolecular Assembly of Hexaaza Macrocyclic Copper(II) Complexes

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Taehyung; Kim, Ju Chang [Pukyong National Univ., Busan (Korea, Republic of); Lough, Alan J. [Univ. of Toronto, Toronto (Canada)

    2013-06-15

    Two new hexaaza macrocyclic copper(II) complexes were prepared by a template method and structurally characterized. In the solid state, they were self-assembled by intermolecular interactions to form the corresponding supramolecules 1 and 2, respectively. In the structure of 1, the copper(II) macrocycles are bridged by a tp ligand to form a macrocyclic copper(II) dimer. The dimer extends its structure by intermolecular forces such as hydrogen bonds and C-H···π interactions, resulting in the formation of a double stranded 1D supramolecule. In 2, the basic structure is a monomeric copper(II) macrocycle with deprotonated imidazole pendants. An undulated 1D hydrogen bonded array is achieved through hydrogen bonds between imidazole pendants and secondary amines, where the imidazole pendants act as a hydrogen bond acceptor. The 1D hydrogen bonded supramolecular chain is supported by C-H···π interactions between the methyl groups of acetonitrile ligands and imidazole pendants of the copper(II) macrocycles. In both complexes, the introduction of imidazoles to the macrocycle as a pendant plays an important role for the formation of supramolecules, where they act as intermolecular hydrogen bond donors and/or acceptors, C-H···π and π-π interactions.

  14. Bonding with Your Baby

    Science.gov (United States)

    ... in infant massage in your area. Breastfeeding and bottle-feeding are both natural times for bonding. Infants respond ... activities include: participating together in labor and delivery feeding ( breast or bottle ); sometimes dad forms a special bond with baby ...

  15. Controlling monomer-sequence using supramolecular templates

    OpenAIRE

    ten Brummelhuis, Niels

    2014-01-01

    The transcription and translation of information contained in nucleic acids that has been perfected by nature serves as inspiration for chemists to devise strategies for the creation of polymers with welldefined monomer sequences. In this review the various approaches in which templates (either biopolymers or synthetic ones) are used to influence the monomer-sequence are discussed.

  16. A lightweight approach for biometric template protection

    Science.gov (United States)

    Al-Assam, Hisham; Sellahewa, Harin; Jassim, Sabah

    2009-05-01

    Privacy and security are vital concerns for practical biometric systems. The concept of cancelable or revocable biometrics has been proposed as a solution for biometric template security. Revocable biometric means that biometric templates are no longer fixed over time and could be revoked in the same way as lost or stolen credit cards are. In this paper, we describe a novel and an efficient approach to biometric template protection that meets the revocability property. This scheme can be incorporated into any biometric verification scheme while maintaining, if not improving, the accuracy of the original biometric system. However, we shall demonstrate the result of applying such transforms on face biometric templates and compare the efficiency of our approach with that of the well-known random projection techniques. We shall also present the results of experimental work on recognition accuracy before and after applying the proposed transform on feature vectors that are generated by wavelet transforms. These results are based on experiments conducted on a number of well-known face image databases, e.g. Yale and ORL databases.

  17. Nanoporous Ag template from partially sintered Ag–Zn compact by dezincification

    Indian Academy of Sciences (India)

    M Mandal; A P Moon; S Sangal; K Mondal

    2014-10-01

    A novel approach is followed to successfully fabricate nanoporous thin Ag template using partial sintering of elemental Ag and Zn (both have 99.9% purity) and subsequent dezincification. The starting materials for dezincification are partially sintered Ag–Zn aggregates (2.5, 5 and 10 wt% Zn). Partial sintering is done in order to achieve only interfacial bonding with the aim to maintain maximum potential difference between Ag and Zn particles during dezincification process in 1 N HCl and 3.5 wt% NaCl solutions. Two different dissolution methods, namely, simple immersion for 45 days and electrochemical way (holding the sample at critical potential), are employed. Electrochemical polarization tests are carried out to determine the critical potential for subsequent chrono-amperometry. X-ray diffraction, optical microscopy, scanning electron microscopy and energy dispersive X-ray spectroscopy are carried out to examine microstructural evolution, size, distribution and nature of pores in sintered aggregate as well as in template.

  18. Acrylic mechanical bond tests

    Energy Technology Data Exchange (ETDEWEB)

    Wouters, J.M.; Doe, P.J.

    1991-02-01

    The tensile strength of bonded acrylic is tested as a function of bond joint thickness. 0.125 in. thick bond joints were found to posses the maximum strength while the acceptable range of joints varied from 0.063 in. to almost 0.25 in. Such joints are used in the Sudbury Neutrino Observatory.

  19. Bond percolation in films

    Science.gov (United States)

    Korneta, W.; Pytel, Z.

    1988-04-01

    Bond percolation in films with simple cubic structure is considered. It is assumed that the probability of a bond being present between nearest-neighbor sites depends on the distances to surfaces. Based on the relation between the Potts model and the bond percolation model, and using the mean-field approximation, the phase diagram and profiles of the percolation probability have been obtained.

  20. Templated Self Assemble of Nano-Structures

    Energy Technology Data Exchange (ETDEWEB)

    Suo, Zhigang [Harvard University

    2013-04-29

    This project will identify and model mechanisms that template the self-assembly of nanostructures. We focus on a class of systems involving a two-phase monolayer of molecules adsorbed on a solid surface. At a suitably elevated temperature, the molecules diffuse on the surface to reduce the combined free energy of mixing, phase boundary, elastic field, and electrostatic field. With no template, the phases may form a pattern of stripes or disks. The feature size is on the order of 1-100 nm, selected to compromise the phase boundary energy and the long-range elastic or electrostatic interaction. Both experimental observations and our theoretical simulations have shown that the pattern resembles a periodic lattice, but has abundant imperfections. To form a perfect periodic pattern, or a designed aperiodic pattern, one must introduce a template to guide the assembly. For example, a coarse-scale pattern, lithographically defined on the substrate, will guide the assembly of the nanoscale pattern. As another example, if the molecules on the substrate surface carry strong electric dipoles, a charged object, placed in the space above the monolayer, will guide the assembly of the molecular dipoles. In particular, the charged object can be a mask with a designed nanoscale topographic pattern. A serial process (e.g., e-beam lithography) is necessary to make the mask, but the pattern transfer to the molecules on the substrate is a parallel process. The technique is potentially a high throughput, low cost process to pattern a monolayer. The monolayer pattern itself may serve as a template to fabricate a functional structure. This project will model fundamental aspects of these processes, including thermodynamics and kinetics of self-assembly, templated self-assembly, and self-assembly on unconventional substrates. It is envisioned that the theory will not only explain the available experimental observations, but also motivate new experiments.

  1. Chemical bond fundamental aspects of chemical bonding

    CERN Document Server

    Frenking, Gernot

    2014-01-01

    This is the perfect complement to ""Chemical Bonding - Across the Periodic Table"" by the same editors, who are two of the top scientists working on this topic, each with extensive experience and important connections within the community. The resulting book is a unique overview of the different approaches used for describing a chemical bond, including molecular-orbital based, valence-bond based, ELF, AIM and density-functional based methods. It takes into account the many developments that have taken place in the field over the past few decades due to the rapid advances in quantum chemica

  2. Effective surface passivation of p-type crystalline silicon with silicon oxides formed by light-induced anodisation

    Energy Technology Data Exchange (ETDEWEB)

    Cui, Jie, E-mail: j.cui@unsw.edu.au [School of Photovoltaic and Renewable Energy Engineering, The University of New South Wales, Sydney 2052 (Australia); Grant, Nicholas [Centre for Sustainable Energy Systems, Australian National University, Canberra, A.C.T. 0200 (Australia); Lennon, Alison [School of Photovoltaic and Renewable Energy Engineering, The University of New South Wales, Sydney 2052 (Australia)

    2014-12-30

    Highlights: • The surface passivation by anodic SiO{sub 2} formed by light-induced anodisation is investigated. • The anodic SiO{sub 2} grows lower temperatures with shorter growth times. After annealing in oxygen and then forming gas the effective minority carrier lifetime is increased to 150 μs. • It shows a very low positive Q{sub eff} of 3.4 × 10{sup 11} cm{sup −2}, a moderate D{sub it} of 6 × 10{sup 11} eV{sup −1} cm{sup −2}. • It has a very low leakage current density suggesting its application in solar cell as a functional dielectric. - Abstract: Electronic surface passivation of p-type crystalline silicon by anodic silicon dioxide (SiO{sub 2}) was investigated. The anodic SiO{sub 2} was grown by light-induced anodisation (LIA) in diluted sulphuric acid at room temperature, a process that is significantly less-expensive than thermal oxidation which is widely-used in silicon solar cell fabrication. After annealing in oxygen and then forming gas at 400 °C for 30 min, the effective minority carrier lifetime of 3–5 Ω cm, boron-doped Czochralski silicon wafers with a phosphorus-doped 80 Ω/□ emitter and a LIA anodic SiO{sub 2} formed on the p-type surface was increased by two orders of magnitude to 150 μs. Capacitance–voltage measurements demonstrated a very low positive charge density of 3.4 × 10{sup 11} cm{sup −2} and a moderate density of interface states of 6 × 10{sup 11} eV{sup −1} cm{sup −2}. This corresponded to a silicon surface recombination velocity of 62 cm s{sup −1}, which is comparable with values reported for other anodic SiO{sub 2} films, which required higher temperatures and longer growth times, and significantly lower than oxides grown by chemical vapour deposition techniques. Additionally, a very low leakage current density of 3.5 × 10{sup −10} and 1.6 × 10{sup −9} A cm{sup −2} at 1 and −1 V, respectively, was measured for LIA SiO{sub 2} suggesting its potential application as insulation layer in

  3. The evaluation of a novel method comparing quantitative light-induced fluorescence (QLF) with spectrophotometry to assess staining and bleaching of teeth

    NARCIS (Netherlands)

    Adeyemi, A.A.; Jarad, F.D.; de Josselin de Jong, E.; Pender, N.; Higham, S.M.

    2010-01-01

    This study reports the development and evaluation of a novel method using quantitative light-induced fluorescence (QLF), which enables its use for quantifying and assessing whole tooth surface staining and tooth whitening. The method was compared with a spectrophotometer to assess reliability. Two e

  4. Kinetics of Light-Induced cis-trans Isomerization of Four Piperines and their Levels in Ground Black Peppers as Determined by HPLC and LC/MS

    Science.gov (United States)

    The pungent compound piperine, a secondary metabolite present in black, white, and green pepper fruit, undergoes light-induced isomerizations. To facilitate studies in this area, an HPLC method has been developed for analysis and isolation of the following four possible piperine photo-induced isomer...

  5. Review of Research on Template Methods in Preparation of Nanomaterials

    Directory of Open Access Journals (Sweden)

    Yadian Xie

    2016-01-01

    Full Text Available The nanomaterials have been widely used in various fields, such as photonics, catalysis, and adsorption, because of their unique physical and chemical properties. Therefore, their production methods are of utmost importance. Compared with traditional synthetic methods, the template method can effectively control the morphology, particle size, and structure during the preparation of nanomaterials, which is an effective method for their synthesis. The key for the template method is to choose different templates, which are divided into hard template and soft template according to their different structures. In this paper, the effects of different types of templates on the morphology of nanomaterials during their preparation are investigated from two aspects: hard template and soft template, combined with the mechanism of action.

  6. Emergency department documentation templates: variability in template selection and association with physical examination and test ordering in dizziness presentations

    Directory of Open Access Journals (Sweden)

    Meurer William J

    2011-03-01

    Full Text Available Abstract Background Clinical documentation systems, such as templates, have been associated with process utilization. The T-System emergency department (ED templates are widely used but lacking are analyses of the templates association with processes. This system is also unique because of the many different template options available, and thus the selection of the template may also be important. We aimed to describe the selection of templates in ED dizziness presentations and to investigate the association between items on templates and process utilization. Methods Dizziness visits were captured from a population-based study of EDs that use documentation templates. Two relevant process outcomes were assessed: head computerized tomography (CT scan and nystagmus examination. Multivariable logistic regression was used to estimate the probability of each outcome for patients who did or did not receive a relevant-item template. Propensity scores were also used to adjust for selection effects. Results The final cohort was 1,485 visits. Thirty-one different templates were used. Use of a template with a head CT item was associated with an increase in the adjusted probability of head CT utilization from 12.2% (95% CI, 8.9%-16.6% to 29.3% (95% CI, 26.0%-32.9%. The adjusted probability of documentation of a nystagmus assessment increased from 12.0% (95%CI, 8.8%-16.2% when a nystagmus-item template was not used to 95.0% (95% CI, 92.8%-96.6% when a nystagmus-item template was used. The associations remained significant after propensity score adjustments. Conclusions Providers use many different templates in dizziness presentations. Important differences exist in the various templates and the template that is used likely impacts process utilization, even though selection may be arbitrary. The optimal design and selection of templates may offer a feasible and effective opportunity to improve care delivery.

  7. Photolabile acetals as profragrances: the effect of structural modifications on the light-induced release of volatile aldehydes on cotton.

    Science.gov (United States)

    Trachsel, Alain; Buchs, Barbara; Herrmann, Andreas

    2016-09-31

    Because volatile compounds evaporate from surfaces that are usually exposed to daylight, photoresponsive delivery systems are particularly suitable to control their release. In the present study, we investigated 4,4-diphenyl-4H-benzo[d][1,3]dioxins as profragrances for the light-induced delivery of aldehydes in functional perfumery. The efficiency of fragrance release was investigated on cotton after direct and indirect surface deposition from a fabric softening formulation as a function of the substitution pattern of the profragrance structure. Dynamic headspace analysis above the cotton surface demonstrated that the structure of the profragrance had a much larger effect on the fragrance release than did the amount of deposition on the target surface. Although some trends observed for the photolysis in solution also applied to the reaction on cotton, it is not generally possible to predict the photochemical behaviour of structurally different precursors on surfaces from their solution properties. The fact that the present system performed on a dry surface makes it an interesting light-triggered delivery vehicle for other classes of bioactive volatile compounds, such as pheromones or agrochemicals.

  8. Modeling light-induced charge transfer dynamics across a metal-molecule-metal junction: bridging classical electrodynamics and quantum dynamics.

    Science.gov (United States)

    Hu, Zixuan; Ratner, Mark A; Seideman, Tamar

    2014-12-14

    We develop a numerical approach for simulating light-induced charge transport dynamics across a metal-molecule-metal conductance junction. The finite-difference time-domain method is used to simulate the plasmonic response of the metal structures. The Huygens subgridding technique, as adapted to Lorentz media, is used to bridge the vastly disparate length scales of the plasmonic metal electrodes and the molecular system, maintaining accuracy. The charge and current densities calculated with classical electrodynamics are transformed to an electronic wavefunction, which is then propagated through the molecular linker via the Heisenberg equations of motion. We focus mainly on development of the theory and exemplify our approach by a numerical illustration of a simple system consisting of two silver cylinders bridged by a three-site molecular linker. The electronic subsystem exhibits fascinating light driven dynamics, wherein the charge density oscillates at the driving optical frequency, exhibiting also the natural system timescales, and a resonance phenomenon leads to strong conductance enhancement.

  9. The Light-Induced Field-Effect Solar Cell Concept - Perovskite Nanoparticle Coating Introduces Polarization Enhancing Silicon Cell Efficiency.

    Science.gov (United States)

    Wang, Yusheng; Xia, Zhouhui; Liu, Lijia; Xu, Weidong; Yuan, Zhongcheng; Zhang, Yupeng; Sirringhaus, Henning; Lifshitz, Yeshayahu; Lee, Shui-Tong; Bao, Qiaoliang; Sun, Baoquan

    2017-03-03

    Solar cell generates electrical energy from light one via pulling excited carrier away under built-in asymmetry. Doped semiconductor with antireflection layer is general strategy to achieve this including crystalline silicon (c-Si) solar cell. However, loss of extra energy beyond band gap and light reflection in particular wavelength range is known to hinder the efficiency of c-Si cell. Here, it is found that part of short wavelength sunlight can be converted into polarization electrical field, which strengthens asymmetry in organic-c-Si heterojunction solar cell through molecule alignment process. The light harvested by organometal trihalide perovskite nanoparticles (NPs) induces molecular alignment on a conducting polymer, which generates positive electrical surface field. Furthermore, a "field-effect solar cell" is successfully developed and implemented by combining perovskite NPs with organic/c-Si heterojunction associating with light-induced molecule alignment, which achieves an efficiency of 14.3%. In comparison, the device with the analogous structure without perovskite NPs only exhibits an efficiency of 12.7%. This finding provides a novel concept to design solar cell by sacrificing part of sunlight to provide "extra" asymmetrical field continuously as to drive photogenerated carrier toward respective contacts under direct sunlight. Moreover, it also points out a method to combine promising perovskite material with c-Si solar cell.

  10. Determination of blue-light-induced infrared absorption based on mode-matching efficiency in an optical parametric oscillator

    Science.gov (United States)

    Wang, Yajun; Yang, Wenhai; Li, Zhixiu; Zheng, Yaohui

    2017-02-01

    Non-classical squeezed states of light at a compatible atomic wavelength have a potential application in quantum information protocols for quantum states delaying or storaging. An optical parametric oscillator (OPO) with periodically poled potassium titanyl phosphate (PPKTP) is the most effective method for generating this squeezed state. However, it is a challege for the nonlinear interaction in PPKTP crystal at the D1 line of rubidium atomic, due to a strong blue-light-induced infrared absorption (BLIIRA). In this paper, we report an indirect measurement method for the BLIIRA through measuring the mode-matching efficiency in an optical parametric oscillator. In contrast to previous works, our method is not limited by the absolute power variation induced from the change of frequency conversion loss and the impedance matching originated from the change of absorption loss. Therefore, the measurement process is performed at the phase-matching condition. The measured results show that BLIIRA coefficient is quadratic dependence of blue light intensity below 1 kW per square centimeter in our PPKTP device, which will provide important basis for optimizing squeezed state generation at 795 nm.

  11. Towards understanding photomigration: Insights from atomistic simulations of azopolymer films explicitly including light-induced isomerization dynamics

    Science.gov (United States)

    Böckmann, Marcus; Doltsinis, Nikos L.

    2016-10-01

    The light-induced surface modification of a thin film of poly-(disperse orange-3-methylmethacrylate) is investigated computationally using atomistic molecular dynamics simulations specifically tailored to include photoisomerization dynamics. For a model surface consisting of a periodic pattern of alternating irradiated and dark spots, it is shown that repeated photoisomerization in the irradiated areas initially leads to a local temperature increase and a raised surface profile accompanied by a migration of molecules away from the bright spots. After switching off the light source and letting the system cool down, this leads to an inversion of the surface profile, i.e., dips in the bright spots and bumps in the dark spots. To separate the effect of photoisomerization from the pure heating effect, a second simulation is performed in which no photoisomerization is allowed to occur in the bright spots, but the equivalent amount of energy is introduced there locally in the form of heat. This also leads to a raised surface in these areas; however, no outward migration of molecules is observed and the surface pattern practically vanishes when the system is subsequently cooled back to room temperature.

  12. Light induced suppression of Kondo effect at amorphous LaAlO3/SrTiO3 interface

    Science.gov (United States)

    Liu, G. Z.; Qiu, J.; Jiang, Y. C.; Zhao, R.; Yao, J. L.; Zhao, M.; Feng, Y.; Gao, J.

    2016-07-01

    We report photoelectric properties of two-dimensional electron gas (2DEG) at an amorphous LaAlO3/SrTiO3 interface. Under visible light illumination (650 nm), an enhancement of electric conductivity is observed over the temperature range from 2 to 300 K. Particularly, a resistance upturn appearing below 25 K, which is further proved to from the Kondo effect, is suppressed by the 650 nm visible light. From the results of light-assisted Hall measurements, light irradiation increases the carrier mobility rather than carrier density in the Kondo regime. It is suggested that light induces the decoherence effect of localized spin states, hence the electron scattering is weakened and the carrier mobility is improved accordingly. Moreover, the enhancement of electrical conductivity by visible light verifies that in-gap states located in the SrTiO3 side of the interface play an important role in the electrical transport of the amorphous SrTiO3-based oxide 2DEG system. Our results provide deeper insight into the photoinduced effects in the 2DEG system, paving the way for the design of optoelectronic devices based on oxides.

  13. Plastid movement impaired 2, a new gene involved in normal blue-light-induced chloroplast movements in Arabidopsis.

    Science.gov (United States)

    Luesse, Darron R; DeBlasio, Stacy L; Hangarter, Roger P

    2006-08-01

    Chloroplasts move in a light-dependent manner that can modulate the photosynthetic potential of plant cells. Identification of genes required for light-induced chloroplast movement is beginning to define the molecular machinery that controls these movements. In this work, we describe plastid movement impaired 2 (pmi2), a mutant in Arabidopsis (Arabidopsis thaliana) that displays attenuated chloroplast movements under intermediate and high light intensities while maintaining a normal movement response under low light intensities. In wild-type plants, fluence rates below 20 micromol m(-2) s(-1) of blue light lead to chloroplast accumulation on the periclinal cell walls, whereas light intensities over 20 micromol m(-2) s(-1) caused chloroplasts to move toward the anticlinal cell walls (avoidance response). However, at light intensities below 75 micromol m(-2) s(-1), chloroplasts in pmi2 leaves move to the periclinal walls; 100 micromol m(-2) s(-1) of blue light is required for chloroplasts in pmi2 to move to the anticlinal cell walls, indicating a shift in the light threshold for the avoidance response in the mutant. The pmi2 mutation has been mapped to a gene that encodes a protein of unknown function with a large coiled-coil domain in the N terminus and a putative P loop. PMI2 shares sequence and structural similarity with PMI15, another unknown protein in Arabidopsis that, when mutated, causes a defect in chloroplast avoidance under high-light intensities.

  14. Three-layered polyplex micelle as a multifunctional nanocarrier platform for light-induced systemic gene transfer

    Science.gov (United States)

    Nomoto, Takahiro; Fukushima, Shigeto; Kumagai, Michiaki; Machitani, Kaori; Arnida; Matsumoto, Yu; Oba, Makoto; Miyata, Kanjiro; Osada, Kensuke; Nishiyama, Nobuhiro; Kataoka, Kazunori

    2014-04-01

    Nanocarriers responding to light have great potential for pinpoint therapy, and recent studies have revealed promising in vivo activity. However, light-selective gene transfer still remains challenging in the systemic application. Here we report systemic light-responsive nanocarriers for gene delivery developed through the sequential self-assembly of ABC-type triblock copolymer/DNA/dendrimeric photosensitizer, forming polyplex micelles with three-layered functional nanocompartments. The DNA-packaged core is covered by the photosensitizer-incorporated intermediate layer, which is encompassed by an outer shielding shell. This three-layered structure permits multistep photosensitizer and DNA delivery into a solid tumour by a systemic route: the shielding layer minimizes unfavourable interactions with blood components, and the photosensitizer is delivered to endo-/lysosomal membranes to facilitate light-selective cytoplasmic translocation of the micelles, accomplishing DNA delivery into the nucleus to exert gene expression. The polyplex micelles display >100-fold photoenhanced gene expression in cultured cells and exhibit light-induced in vivo gene transfer in solid tumours following systemic administration.

  15. Non-rigid contour-to-pixel registration of photographic and quantitative light-induced fluorescence imaging of decalcified teeth

    Science.gov (United States)

    Berkels, Benjamin; Deserno, Thomas; Ehrlich, Eva E.; Fritz, Ulrike B.; Sirazitdinova, Ekaterina; Tatano, Rosalia

    2016-03-01

    Quantitative light-induced fluorescence (QLF) is widely used to assess the damage of a tooth due to decalcification. In digital photographs, decalcification appears as white spot lesions, i.e. white spots on the tooth surface. We propose a novel multimodal registration approach for the matching of digital photographs and QLF images of decalcified teeth. The registration is based on the idea of contour-to-pixel matching. Here, the curve, which represents the shape of the tooth, is extracted from the QLF image using a contour segmentation by binarization and morphological processing. This curve is aligned to the photo with a non-rigid variational registration approach. Thus, the registration problem is formulated as minimization problem with an objective function that consists of a data term and a regularizer for the deformation. To construct the data term, the photo is pointwise classified into tooth and non-tooth regions. Then, the signed distance function of the tooth region allows to measure the mismatch between curve and photo. As regularizer a higher order, linear elastic prior is used. The resulting minimization problem is solved numerically using bilinear Finite Elements for the spatial discretization and the Gauss-Newton algorithm. The evaluation is based on 150 image pairs, where an average of 5 teeth have been captured from 32 subjects. All registrations have been confirmed correctly by a dental expert. The contour-to-pixel methods can directly be used in 3D for surface-to-voxel tasks.

  16. Photochemical synthesis, characterization and enhanced visible light induced photocatalysis of Ag modified TiO2 nanocatalyst.

    Science.gov (United States)

    Ko, Seonghyuk

    2014-09-01

    Nanocomposite of titania (TiO2) and silver (Ag) has been synthesized by a photochemical deposition method. We investigated the simultaneous enhancement of visible light sensitivity and photocatalytic activities of as-prepared Ag-TiO2 nanocomposite photocatalyst. The resulting Ag-TiO2 nanomaterials were characterized by various analytical techniques including X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), UV-Vis diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS) and photoluminescence (PL). Photocatalytic activity was evaluated by decomposition of methylene blue (MB) dye solution under simulated visible light irradiation. Ag nanoparticles were well dispersed on the surface of TiO2 and composite nanoparticles were effectively enhanced in visible light-induced photocatalytic activity compared to that of Ag free TiO2. It was found that the enhanced activity is result from simultaneous effects of nano-Ag deposits by increasing the absorption capacity in visible region and by acting as electron trappers to promote charge separation of photoinduced electrons (e-) and holes (h+). The effect of the amount of Ag nanoparticles on its photoactivity under simulated visible light was also investigated.

  17. Light-induced EPR study of charge transfer in P3HT/bis-PCBM bulk heterojunctions

    Directory of Open Access Journals (Sweden)

    Victor I. Krinichnyi

    2011-06-01

    Full Text Available Radical pairs, polarons and fullerene anion radicals photoinduced by photons with energy of 1.98 – 2.73 eV in bulk heterojunctions formed by poly(3-hexylthiophene (P3HT with bis(1-[3-(methoxycarbonylpropyl]-1-phenyl-[6.6]C62 (bis-PCBM fullerene derivative have been studied by direct light-induced EPR (LEPR method in a wide temperature range. A part of photoinduced polarons are pinned in trap sites which number and depth are governed by an ordering of the polymer/fullerene system and energy of initiating photons. It was shown that dynamics and recombination of mobile polarons and counter fullerene anion radicals are governed by their exchange- and multi-trap assisted diffusion. Relaxation and dynamics parameters of both the charge carriers were determined separately by the steady-state saturation method. These parameters are governed by structure and conformation of the carriers’ microenvironment as well as by the energy of irradiating photons. Longitudinal diffusion of polarons was shown to depend on lattice phonons of crystalline domains embedded into an amorphous polymer matrix. The energy barrier required for polaron interchain hopping is higher than that its intrachain diffusion. Pseudorotation of fullerene derivatives in a polymer matrix was shown to follow the activation Pike model.

  18. Business Process Variability : A Tool for Declarative Template Design

    NARCIS (Netherlands)

    Bulanov, P.; Groefsema, H.; Aiello, M.

    2012-01-01

    To lower both implementation time and cost, many Business Process Management tools use process templates to implement highly recurring processes. However, in order for such templates to be used, a process has to adhere substantially to the template. Therefore, current practice for processes which de

  19. Templated electrodeposition of functional nanostructures: nanowires, nanotubes and nanocubes

    NARCIS (Netherlands)

    Maijenburg, Albert Wouter

    2014-01-01

    This thesis is entitled “Templated electrodeposition of functional nanostructures: nanowires, nanotubes and nanocubes”. Templated electrodeposition is the synthesis technique that was used throughout this thesis, and it comprises the use of a template with specific shape and dimensions for the forma

  20. Extraordinary improvement of the graphitic structure of continuous carbon nanofibers templated with double wall carbon nanotubes.

    Science.gov (United States)

    Papkov, Dimitry; Beese, Allison M; Goponenko, Alexander; Zou, Yan; Naraghi, Mohammad; Espinosa, Horacio D; Saha, Biswajit; Schatz, George C; Moravsky, Alexander; Loutfy, Raouf; Nguyen, Sonbinh T; Dzenis, Yuris

    2013-01-22

    Carbon nanotubes are being widely studied as a reinforcing element in high-performance composites and fibers at high volume fractions. However, problems with nanotube processing, alignment, and non-optimal stress transfer between the nanotubes and surrounding matrix have so far prevented full utilization of their superb mechanical properties in composites. Here, we present an alternative use of carbon nanotubes, at a very small concentration, as a templating agent for the formation of graphitic structure in fibers. Continuous carbon nanofibers (CNF) were manufactured by electrospinning from polyacrylonitrile (PAN) with 1.2% of double wall nanotubes (DWNT). Nanofibers were oxidized and carbonized at temperatures from 600 °C to 1850 °C. Structural analyses revealed significant improvements in graphitic structure and crystal orientation in the templated CNFs, with the largest improvements observed at lower carbonization temperatures. In situ pull-out experiments showed good interfacial bonding between the DWNT bundles and the surrounding templated carbon matrix. Molecular Dynamics (MD) simulations of templated carbonization confirmed oriented graphitic growth and provided insight into mechanisms of carbonization initiation. The obtained results indicate that global templating of the graphitic structure in fine CNFs can be achieved at very small concentrations of well-dispersed DWNTs. The outcomes reveal a simple and inexpensive route to manufacture continuous CNFs with improved structure and properties for a variety of mechanical and functional applications. The demonstrated improvement of graphitic order at low carbonization temperatures in the absence of stretch shows potential as a promising new manufacturing technology for next generation carbon fibers.

  1. Synthesis and Study of Guest-Rebinding of MIP Based on MAA Prepared using Theophylline Template

    Science.gov (United States)

    Nurhayati, T.; Yanti; Royani, I.; Widayani; Khairurrijal

    2016-08-01

    A molecularly imprinted polymer (MIP) based on methacrylic acid (MAA) monomer and theophylline template has been synthesized using a modified bulk polymerization method. Theophylline was employed as a template and it formed a complex with MAA through hydrogen bonding. Self-assembly of template-monomer was followed by cross-linking process using ethylene glycol dimethacrylate (EGDMA) cross-linker. The polymerization process was initiated by thermal decomposition of benzoyl peroxide (BPO) as the initiator at 60oC after cooling treatment at -5oC. After 7 hours, a rigid polymer was obtained and followed by grinding the polymer and removing the template. As a reference, a nonimprinted polymer (NIP) has also been synthesized using similar procedure by excluding the template. FTIR study was carried out to investigate the presence of theophylline in the as- prepared polymer, MIP, and NIP. The spectra indicated that theophylline was successfully incorporated in the as-prepared polymer. This result was also confirmed by EDS analysis showing that N atoms of the as-prepared polymer were derived from amino group of theophylline. Furthermore, the polymer particles of MIP were irregular in shape and size as shown by its SEM image. The capability of guest-rebinding of the MIP was analyzed through Batchwise guest-binding experiment. The results showed that for initial concentration of theophylline in methanol/chloroform (1/1, v/v) of 0.333 mM, the binding capacity of the MIP was 23.22 /mol/g. Compared to the MIP, the adsorption capacity of the NIP was only 3.73 /mol/g. This result shows that MIP has higher affinity than NIP.

  2. Halogen- and hydrogen-bonding catenanes for halide-anion recognition.

    Science.gov (United States)

    Gilday, Lydia C; Beer, Paul D

    2014-07-01

    Halogen-bonding (XB) interactions were exploited in the solution-phase assembly of anion-templated pseudorotaxanes between an isophthalamide-containing macrocycle and bromo- or iodo-functionalised pyridinium threading components. (1)H NMR spectroscopic titration investigations demonstrated that such XB interpenetrated assemblies are more stable than analogous hydrogen bonding (HB) pseudorotaxanes. The stability of the anion-templated halogen-bonded pseudorotaxane architectures was exploited in the preparation of new halogen-bonding interlocked catenane species through a Grubbs' ring-closing metathesis (RCM) clipping methodology. The catenanes' anion recognition properties in the competitive CDCl(3)/CD(3) OD 1:1 solvent mixture revealed selectivity for the heavier halides iodide and bromide over chloride and acetate.

  3. The fabrication of high sensitivity gold nanorod H2S gas sensors utilizing the highly uniform anodic aluminum oxide template

    Science.gov (United States)

    Li, Chien-Yu; Li, Ciao-Yu; Wu, You-Lin; Hsu, Chung-Ping; Lee, Ming-Ching; Houng, Mau-Phon

    2016-12-01

    Gold nanorod were fabricated using anodic alumina oxide template for H2S gas detection. The nanorod gas sensor exhibits high surface density and contact area, which can increase detection sensitivity. The anodic alumina oxide template contains an array of pores, with a width of 70 nm and a length of 27 μ m . Au nanorod were obtained through electro-deposition under a pulse bias of -1 V. The resistance of the Au nanorod was recorded upon exposure to various concentrations of H2S. The resistance could be attributed to the high electron affinity between sulfide and Au nanorod. Au-sulfide bonds provide strong bonding, which could alter the conductivity of the sensor. The gas sensor exhibits high sensitivity and short response time for H2S detection at room temperature.

  4. The fabrication of high sensitivity gold nanorod H2S gas sensors utilizing the highly uniform anodic aluminum oxide template

    Directory of Open Access Journals (Sweden)

    Chien-Yu Li

    2016-12-01

    Full Text Available Gold nanorod were fabricated using anodic alumina oxide template for H2S gas detection. The nanorod gas sensor exhibits high surface density and contact area, which can increase detection sensitivity. The anodic alumina oxide template contains an array of pores, with a width of 70 nm and a length of 27μm. Au nanorod were obtained through electro-deposition under a pulse bias of −1 V. The resistance of the Au nanorod was recorded upon exposure to various concentrations of H2S. The resistance could be attributed to the high electron affinity between sulfide and Au nanorod. Au–sulfide bonds provide strong bonding, which could alter the conductivity of the sensor. The gas sensor exhibits high sensitivity and short response time for H2S detection at room temperature.

  5. Template-Guided Self-Assembly of Discrete Optoplasmonic Molecules and Extended Optoplasmonic Arrays

    Directory of Open Access Journals (Sweden)

    Reinhard Björn M.

    2015-01-01

    Full Text Available The integration of metallic and dielectric building blocks into optoplasmonic structures creates new electromagnetic systems in which plasmonic and photonic modes can interact in the near-, intermediate- and farfield. The morphology-dependent electromagnetic coupling between the different building blocks in these hybrid structures provides a multitude of opportunities for controlling electromagnetic fields in both spatial and frequency domain as well as for engineering the phase landscape and the local density of optical states. Control over any of these properties requires, however, rational fabrication approaches for well-defined metal-dielectric hybrid structures. Template-guided self-assembly is a versatile fabrication method capable of integrating metallic and dielectric components into discrete optoplasmonic structures, arrays, or metasurfaces. The structural flexibility provided by the approach is illustrated by two representative implementations of optoplasmonic materials discussed in this review. In optoplasmonic atoms or molecules optical microcavities (OMs serve as whispering gallery mode resonators that provide a discrete photonic mode spectrum to interact with plasmonic nanostructures contained in the evanescent fields of the OMs. In extended hetero-nanoparticle arrays in-plane scattered light induces geometry-dependent photonic resonances that mix with the localized surface plasmon resonances of the metal nanoparticles.We characterize the fundamental electromagnetic working principles underlying both optoplasmonic approaches and review the fabrication strategies implemented to realize them.

  6. Metathesis depolymerization for removable surfactant templates.

    Energy Technology Data Exchange (ETDEWEB)

    Zifer, Thomas (Sandia National Laboratories, Livermore, CA); Wheeler, David Roger; Rahimian, Kamayar; McElhanon, James Ross (Sandia National Laboratories, Livermore, CA); Long, Timothy Michael; Jamison, Gregory Marks; Loy, Douglas Anson (Los Alamos National Laboratories, Los Alamos, NM); Kline, Steven R. (National Institute of Standards and Technology, Gaithersburg, MD); Simmons, Blake Alexander (Sandia National Laboratories, Livermore, CA)

    2005-03-01

    Current methodologies for the production of meso- and nanoporous materials include the use of a surfactant to produce a self-assembled template around which the material is formed. However, post-production surfactant removal often requires centrifugation, calcination, and/or solvent washing which can damage the initially formed material architecture(s). Surfactants that can be disassembled into easily removable fragments following material preparation would minimize processing damage to the material structure, facilitating formation of templated hybrid architectures. Herein, we describe the design and synthesis of novel cationic and anionic surfactants with regularly spaced unsaturation in their hydrophobic hydrocarbon tails and the first application of ring closing metathesis depolymerization to surfactant degradation resulting in the mild, facile decomposition of these new compounds to produce relatively volatile nonsurface active remnants.

  7. Physical synthesis of quantum circuits using templates

    Science.gov (United States)

    Mirkhani, Zahra; Mohammadzadeh, Naser

    2016-10-01

    Similar to traditional CMOS circuits, quantum circuit design flow is divided into two main processes: logic synthesis and physical design. Addressing the limitations imposed on optimization of the quantum circuit metrics because of no information sharing between logic synthesis and physical design processes, the concept of " physical synthesis" was introduced for quantum circuit flow, and a few techniques were proposed for it. Following that concept, in this paper a new approach for physical synthesis inspired by template matching idea in quantum logic synthesis is proposed to improve the latency of quantum circuits. Experiments show that by using template matching as a physical synthesis approach, the latency of quantum circuits can be improved by more than 23.55 % on average.

  8. Carbon Nanotube Templated Asembly of Protein

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Guodong; Lin, Yuehe

    2006-04-01

    This paper describes a novel general strategy for fabricating protein-polyion multilayers by electrostatic layer-by-layer (LBL) self-assembly on a carbon nanotube (CNT) template. Such a noncovalent functionalization method is important for preserving the activity of biomolecules and the mechanical and electrical properties of CNTs. Glucose oxidase and poly (diallydimethylammonium) chloride polymer were used as a model to investigate the LBL process on a CNT template. High-resolution transmission electron microscopy and electrochemical characterization confirm the formation of LBL nanostructures on carboxyl functionalized CNTs. We have also demonstrated the applications of these nanoshell bioreactors to the direct electrochemistry of proteins and biosensing. This strategy can be applied to assemble other biological molecules, such as antibodies, antigens, and DNA, for wide bioassay applications.

  9. Template-directed synthesis of flexible porphyrin nanocage and nanorings via one-step olefin metathesis.

    Science.gov (United States)

    Zhu, Bin; Chen, Huanxin; Lin, Wei; Ye, Yang; Wu, Jing; Li, Shijun

    2014-10-29

    We describe the fabrication of a suite of flexible porphyrin cages and nanorings from a simple tetraalkene-derived zinc porphyrin monomer via a highly efficient template-directed strategy. The zinc porphyrin monomers were preorganized together by coordination with N atoms of multidentate ligands. Subsequent one-step olefin metathesis furnished a bisporphyrin cage, a triporphyrin nanoring, and a hexaporphyrin nanoring. In the case of the hexaporphyrin nanoring, 24 terminal olefins from six porphyrin monomers reacted with each other to form 12 new double bonds, delivering the final product. The triporphyrin and hexaporphyrin nanorings were further employed as hosts to encapsulate C60 and C70.

  10. Self-assembly of DNA-polymer complexes using template polymerization.

    Science.gov (United States)

    Trubetskoy, V S; Budker, V G; Hanson, L J; Slattum, P M; Wolff, J A; Hagstrom, J E

    1998-09-15

    The self-assembly of supramolecular complexes of nucleic acids and polymers is of relevance to several biological processes including viral and chromatin formation as well as gene therapy vector design. We now show that template polymerization facilitates condensation of DNA into particles that are <150 nm in diameter. Inclusion of a poly(ethylene glycol)-containing monomer prevents aggregation of these particles. The DNA within the particles remains biologically active and can express foreign genes in cells. The formation or breakage of covalent bonds has until now not been employed to compact DNA into artificial particles.

  11. Multibiometric Systems: Fusion Strategies and Template Security

    Science.gov (United States)

    2008-01-01

    41–44, Toledo , Spain, May 2004. [21] R. Cappelli, A. Lumini, D. Maio, and D. Maltoni. Fingerprint Image Recon- struction From Standard Templates. IEEE...Bowyer, S. Sarkar, and B. Victor . Comparison and Combina- tion of Ear and Face Images in Appearance-based Biometrics. IEEE Transac- tions on Pattern...Chronicles. In Odyssey: The Speaker and Language Recognition Workshop, pages 12–22, Toledo , Spain, May 2004. [157] A. Rakhlin, D. Panchenko, and S

  12. Deep Human Parsing with Active Template Regression.

    Science.gov (United States)

    Liang, Xiaodan; Liu, Si; Shen, Xiaohui; Yang, Jianchao; Liu, Luoqi; Dong, Jian; Lin, Liang; Yan, Shuicheng

    2015-12-01

    In this work, the human parsing task, namely decomposing a human image into semantic fashion/body regions, is formulated as an active template regression (ATR) problem, where the normalized mask of each fashion/body item is expressed as the linear combination of the learned mask templates, and then morphed to a more precise mask with the active shape parameters, including position, scale and visibility of each semantic region. The mask template coefficients and the active shape parameters together can generate the human parsing results, and are thus called the structure outputs for human parsing. The deep Convolutional Neural Network (CNN) is utilized to build the end-to-end relation between the input human image and the structure outputs for human parsing. More specifically, the structure outputs are predicted by two separate networks. The first CNN network is with max-pooling, and designed to predict the template coefficients for each label mask, while the second CNN network is without max-pooling to preserve sensitivity to label mask position and accurately predict the active shape parameters. For a new image, the structure outputs of the two networks are fused to generate the probability of each label for each pixel, and super-pixel smoothing is finally used to refine the human parsing result. Comprehensive evaluations on a large dataset well demonstrate the significant superiority of the ATR framework over other state-of-the-arts for human parsing. In particular, the F1-score reaches 64.38 percent by our ATR framework, significantly higher than 44.76 percent based on the state-of-the-art algorithm [28].

  13. CPU and GPU (Cuda Template Matching Comparison

    Directory of Open Access Journals (Sweden)

    Evaldas Borcovas

    2014-05-01

    Full Text Available Image processing, computer vision or other complicated opticalinformation processing algorithms require large resources. It isoften desired to execute algorithms in real time. It is hard tofulfill such requirements with single CPU processor. NVidiaproposed CUDA technology enables programmer to use theGPU resources in the computer. Current research was madewith Intel Pentium Dual-Core T4500 2.3 GHz processor with4 GB RAM DDR3 (CPU I, NVidia GeForce GT320M CUDAcompliable graphics card (GPU I and Intel Core I5-2500K3.3 GHz processor with 4 GB RAM DDR3 (CPU II, NVidiaGeForce GTX 560 CUDA compatible graphic card (GPU II.Additional libraries as OpenCV 2.1 and OpenCV 2.4.0 CUDAcompliable were used for the testing. Main test were made withstandard function MatchTemplate from the OpenCV libraries.The algorithm uses a main image and a template. An influenceof these factors was tested. Main image and template have beenresized and the algorithm computing time and performancein Gtpix/s have been measured. According to the informationobtained from the research GPU computing using the hardwarementioned earlier is till 24 times faster when it is processing abig amount of information. When the images are small the performanceof CPU and GPU are not significantly different. Thechoice of the template size makes influence on calculating withCPU. Difference in the computing time between the GPUs canbe explained by the number of cores which they have.

  14. Template learning in morphological neural nets

    Science.gov (United States)

    Davidson, Jennifer L.; Sun, K.

    1991-07-01

    This paper presents an application of morphology neural networks to a template learning problem. Morphology neural networks are a nonlinear version of the familiar artificial neural networks. Typically, an artificial neural net is used to solve pattern classification problems One useful characterization of many neural network algorithms is the ability to 'learn' to respond correctly to new data based only on a selection of known data responses. For example, in the multilayer perceptron model, the 'learning' is a procedure whereby parameters are fed back from output to input neurons and the weights changed to give a better response. The morphological neural net in this paper solves a different type of image processing problem. Specifically, given an input image and an output image which corresponds to a dilated version of the input, one would like to determine what template produced the output. The problem corresponds to teaching the network to solve for the weights in a morphological net, as the weights are the template's values. A reasonable method has been investigated for the boolean case; in this paper results are presented for gray scale images. Image algebra has been shown to provide a succinct expression of neural networks algorithms and also to allow a generalization of neural networks, and thus the authors describe the algorithm in image algebra. The remainder of the paper gives a brief discussion of image algebra, the relationship of image algebra and neural networks, a recap of the dilation morphology neural network boolean for boolean images, and the generalization to grayscale data.

  15. Sacrificial template method of fabricating a nanotube

    Science.gov (United States)

    Yang, Peidong; He, Rongrui; Goldberger, Joshua; Fan, Rong; Wu, Yi-Ying; Li, Deyu; Majumdar, Arun

    2007-05-01

    Methods of fabricating uniform nanotubes are described in which nanotubes were synthesized as sheaths over nanowire templates, such as using a chemical vapor deposition process. For example, single-crystalline zinc oxide (ZnO) nanowires are utilized as templates over which gallium nitride (GaN) is epitaxially grown. The ZnO templates are then removed, such as by thermal reduction and evaporation. The completed single-crystalline GaN nanotubes preferably have inner diameters ranging from 30 nm to 200 nm, and wall thicknesses between 5 and 50 nm. Transmission electron microscopy studies show that the resultant nanotubes are single-crystalline with a wurtzite structure, and are oriented along the direction. The present invention exemplifies single-crystalline nanotubes of materials with a non-layered crystal structure. Similar "epitaxial-casting" approaches could be used to produce arrays and single-crystalline nanotubes of other solid materials and semiconductors. Furthermore, the fabrication of multi-sheath nanotubes are described as well as nanotubes having multiple longitudinal segments.

  16. UV NIL template making and imprint evaluation

    Science.gov (United States)

    Sasaki, Shiho; Hiraka, Takaaki; Mizuochi, Jun; Sakai, Yuko; Yusa, Satoshi; Morikawa, Yasutaka; Mohri, Hiroshi; Hayashi, Naoya

    2009-01-01

    UV NIL shows excellent resolution capability with remarkable low line edge roughness, and has been attracting pioneers in the industry who were searching for the finest patterns. We have been focused on the resolution improvement in NIL template making with a 100keV acceleration voltage spot beam EB writer process, and have established a template making process to meet the requirements of the pioneers. Usually such templates needed just a small field (several hundred microns square or so) Now, for several semiconductor devices, the UV NIL is considered not only as a patterning solution for R&D purpose but eventually as a potential candidate for production, and instead of a small field, a full chip field mask is required. Although the 100kV EB writers have excellent resolution capability, they are adopting spot beams (SB) to generate the pattern and have a fatally low throughput if we need full chip writing. In this paper, we are focusing on the 50keV variable shaped beam (VSB) EB writers, which are used in current 4X photomask manufacturing. The 50keV VSB writers can generate full chip pattern in a reasonable time, and by choosing the right patterning material and process, we achieved resolution down to hp28nm, and initial promising results of hp22nm (partial resolution) for line and spaces, and hp26nm for dense holes were observed..

  17. Materials integration for high-performance photovoltaics by wafer bonding

    Science.gov (United States)

    Zahler, James Michael

    The fundamental efficiency limit for state of the art triple-junction photovoltaic devices is being approached. By allowing integration of non-lattice-matched materials in monolithic structures, wafer bonding enables novel photovoltaic devices that have a greater number of subcells to improve the discretization of the solar spectrum, thus extending the efficiency limit of the devices. Additionally, wafer bonding enables the integration of non-lattice-matched materials with foreign substrates to confer desirable properties associated with the handle substrate on the solar cell structure, such as reduced mass, increased thermal conductivity, and improved mechanical toughness. This thesis outlines process development and characterization of wafer bonding integration technologies essential for transferring conventional triple-junction solar cell designs to potentially lower cost Ge/Si epitaxial templates. These epitaxial templates consist of a thin film of single-crystal Ge on a Si handle substrate. Additionally, a novel four-junction solar cell design consisting of non-lattice matched subcells of GaInP, GaAs, InGaAsP, and InGaAs based on InP/Si wafer-bonded epitaxial templates is proposed and InP/Si template fabrication and characterization is pursued. In this thesis the detailed-balance theory of the thermodynamic limiting performance of solar cell efficiency is applied to several device designs enabled by wafer bonding and layer exfoliation. The application of the detailed-balance theory to the novel four-junction cell described above shows that operating under 100 suns at 300 K a maximum efficiency of 54.9% is achievable with subcell bandgaps of 1.90, 1.42, 1.02, and 0.60 eV, a material combination achievable by integrating two wide-bandgap subcells lattice matched to GaAs and two narrow-bandgap subcells lattice matched to InP. Wafer bonding and layer transfer processes with sufficient quality to enable subsequent material characterization are demonstrated for both

  18. Converting Basic D3 Charts into Reusable Style Templates.

    Science.gov (United States)

    Harper, Jonathan; Agrawala, Maneesh

    2017-02-07

    We present a technique for converting a basic D3 chart into a reusable style template. Then, given a new data source we can apply the style template to generate a chart that depicts the new data, but in the style of the template. To construct the style template we first deconstruct the input D3 chart to recover its underlying structure: the data, the marks and the mappings that describe how the marks encode the data. We then rank the perceptual effectiveness of the deconstructed mappings. To apply the resulting style template to a new data source we first obtain importance ranks for each new data field. We then adjust the template mappings to depict the source data by matching the most important data fields to the most perceptually effective mappings. We show how the style templates can be applied to source data in the form of either a data table or another D3 chart. While our implementation focuses on generating templates for basic chart types (e.g. variants of bar charts, line charts, dot plots, scatterplots, etc.), these are the most commonly used chart types today. Users can easily find such basic D3 charts on the Web, turn them into templates, and immediately see how their own data would look in the visual style (e.g. colors, shapes, fonts, etc.) of the templates. We demonstrate the effectiveness of our approach by applying a diverse set of style templates to a variety of source datasets.

  19. The Subcellular Localization and Blue-Light-Induced Movement of Phototropin 1-GFP in Etiolated Seedlings of Arabidopsis thaliana

    Institute of Scientific and Technical Information of China (English)

    Ying-Lang Wan; William Eisinger; David Ehrhardt; Ulrich Kubitscheck; Frantisek Baluska; Winslow Briggs

    2008-01-01

    Phototropin 1 (phot1) is a photoreceptor for phototropism, chloroplast movement, stomatal opening, leaf expansion, and solar tracking in response to blue light. Following earlier work with PHOT1::GFP (Sakamoto and Briggs,2002), we investigated the pattern of cellular and subcellular localization of phot1 in 3-4 d old etiolated seedlings of Arabidopsis thalinana. As expressed from native upstream sequences, the PHOT1::GFP fusion protein is expressed strongly in the abaxial tissues of the cotyledons and in the elongating regions of the hypocotyl. It is moderately expressed in the shoot/root transition zone and in cells near the root apex. A fluorescence signal is undetectable in the root epidermis, root cap, and root apical meristem itself. The plasma membranes of mesophyll cells near the cotyledon margin appear labeled uniformly but cross-walls created by recent cell divisions are more strongly labeled. The pattern of labeling of individual cell types varies with cell type and developmental stage. Blue-light treatment causes PHOT1::GFP, initially relatively evenly distributed at the plasma membrane, to become reorganized into a distinct mosaic with strongly labeled punctate areas and other areas completely devoid of fluorescence-a phenomenon best observed in cortical cells in the hypocotyl elongation region. Concomitant with or following this reorganization, PHOT1::GFP moves into the cytoplasm in all cell types investigated except for guard cells. It disappears from the cytoplasm by an unidentified mechanism after several hours in darkness. Neither its appearance in the cytoplasm nor its eventual disappearance in darkness is prevented by the translation inhibitor cycloheximide, although the latter process is retarded. We hypothesize that blue-light-induced phot1 relocalization modulates blue-light-activated signal transduction.

  20. Transcriptome analysis of the exocarp of apple fruit identifies light-induced genes involved in red color pigmentation.

    Science.gov (United States)

    Vimolmangkang, Sornkanok; Zheng, Danman; Han, Yuepeng; Khan, M Awais; Soria-Guerra, Ruth Elena; Korban, Schuyler S

    2014-01-15

    Although the mechanism of light regulation of color pigmentation of apple fruit is not fully understood, it has been shown that light can regulate expression of genes in the anthocyanin biosynthesis pathway by inducing transcription factors (TFs). Moreover, expression of genes encoding enzymes involved in this pathway may be coordinately regulated by multiple TFs. In this study, fruits on trees of apple cv. Red Delicious were covered with paper bags during early stages of fruit development and then removed prior to maturation to analyze the transcriptome in the exocarp of apple fruit. Comparisons of gene expression profiles of fruit covered with paper bags (dark-grown treatment) and those subjected to 14 h light treatment, following removal of paper bags, were investigated using an apple microarray of 40,000 sequences. Expression profiles were investigated over three time points, at one week intervals, during fruit development. Overall, 736 genes with expression values greater than two-fold were found to be modulated by light treatment. Light-induced products were classified into 19 categories with highest scores in primary metabolism (17%) and transcription (12%). Based on the Arabidopsis gene ontology annotation, 18 genes were identified as TFs. To further confirm expression patterns of flavonoid-related genes, these were subjected to quantitative RT-PCR (qRT-PCR) using fruit of red-skinned apple cv. Red Delicious and yellow-skinned apple cv. Golden Delicious. Of these, two genes showed higher levels of expression in 'Red Delicious' than in 'Golden Delicious', and were likely involved in the regulation of fruit red color pigmentation.

  1. Ultraviolet B light-induced apoptosis in human keratinocytes enriched with epidermal stem cells and normal keratinocytes

    Institute of Scientific and Technical Information of China (English)

    MEI Xue-ling; LIAN Shi

    2011-01-01

    Background The stem-cell compartment is the primary target for the accumulation of oncogenic mutations.Overexposure to solar ultraviolet radiation is responsible for the development and progression of >90% of skin cancers.Ultraviolet B (UVB) light-induced keratinocyte apoptosis is a strong preventive mechanism against carcinogenesis. The aim of this study was to isolate keratinocytes enriched with putative human epidermal stem cells and to investigate their apoptotic induction by UVB.Methods Keratinocytes enriched with putative human epidermal stem cells were isolated by adherence to collagen Ⅳ and the expressions of β1-integrin and p63 were investigated. Keratinocytes enriched with putative human epidermal stem cells and normal keratinocytes were irradiated with UVB at 0-80 mJ/cm2. The apoptotic response was investigated with phase-contrast microscopy, Hoechst 33342 staining, flow cytometry of annexin V/PI, and procaspase-3 Western blotting.Results Keratinocyte enriched with stem cells expressed high levels of p63 protein and β1-integrin and low level of pan-keratin (C11). In comparison to non-irradiated cells, significant apoptosis of keratinocyte enriched with stem cells was found with 40 and 80 mJ/cm2 UVB. However, significant apoptosis of normal keratinocytes was only found for 80 mJ/cm2 UVB.Conclusions Human epidermal stem cells can undergo apoptosis in response to UVB radiation and are more susceptible than other keratinocytes. The method could be used in vitro studies of human epidermal stem cells.

  2. Simulations of light induced processes in water based on ab initio path integrals molecular dynamics. II. Photoionization

    Science.gov (United States)

    Svoboda, Ondřej; Ončák, Milan; Slavíček, Petr

    2011-10-01

    We have applied ab initio based reflection principle to simulate photoelectron spectra of small water clusters, ranging from monomer to octamer. The role of quantum and thermal effects on the structure of the water photoelectron spectra is discussed within the ab initio path integral molecular dynamics (PIMD) framework. We have used the PIMD method with up to 40 beads to sample the ground state quantum distribution at temperature T = 180 K. We have thoroughly tested the performance of various density functionals (B3LYP, BHandHLYP, M06HF, BNL, LC-ωPBE, and CAM-B3LYP) for the ionization process description. The benchmarking based on a comparison of simulated photoelectron spectra to experimental data and high level equation-of-motion ionization potential coupled clusters with singles and doubles calculations has singled out the BHandHLYP and LC-ωPBE functionals as the most reliable ones for simulations of light induced processes in water. The good performance of the density functional theory functionals to model the water photoelectron spectra also reflects their ability to reliably describe open shell excited states. The width of the photoelectron spectrum converges quickly with the cluster size as it is controlled by specific interactions of local character. The peak position is, on the other hand, defined by long-range non-specific solvent effects; it therefore only slowly converges to the corresponding bulk value. We are able to reproduce the experimental valence photoelectron spectrum of liquid water within the combined model of the water octamer embedded in a polarizable dielectric continuum. We demonstrate that including the long-range polarization and the state-specific treatment of the solvent response are needed for a reliable liquid water ionization description.

  3. Effect of melatonin on monochromatic light-induced T-lymphocyte proliferation in the thymus of chickens.

    Science.gov (United States)

    Chen, Fuju; Reheman, Aikebaier; Cao, Jing; Wang, Zixu; Dong, Yulan; Zhang, Yuxian; Chen, Yaoxing

    2016-08-01

    A total of 360 post-hatching day 0 (P0) Arbor Acre male broilers, including intact, sham operation and pinealectomy groups, were exposed to white light (WL), red light (RL), green light (GL) and blue light (BL) from a light-emitting diode (LED) system until for P14. We studied the effects of melatonin and its receptors on monochromatic light-induced T-lymphocyte proliferation in the thymus of broilers. The density of proliferating cell nuclear antigen (PCNA) cells and the proliferation of T-lymphocytes in response to Concanavalin A (ConA) in GL significantly increased both in vivo and in vitro (from 9.57% to 32.03% and from 34.30% to 50.53%, respectively) compared with other lights (plights (p<0.005). However, exogenous melatonin (10(-9)M) significantly increased the proliferative activity of T-lymphocyte by 9.64% (p=0.002). In addition, GL significantly increased mRNA expression levels of Mel1a, Mel1b and Mel1c receptors from 21.09% to 32.57%, and protein expression levels from 24.43% to 42.92% compared with RL (p<0.05). However, these effects were blocked after pinealectomy. Furthermore, 4P-PDOT (a selective Mel1b antagonist) and prazosin (a selective Mel1c antagonist) attenuated GL-induced T-lymphocyte proliferation in response to ConA (p=0.000). Luzindole (a nonselective Mel1a/Mel1b antagonist), however, did not induce these effects (p=0.334). These results suggest that melatonin may mediate GL-induced T-lymphocyte proliferation via the Mel1b and Mel1c receptors but not via the Mel1a receptor.

  4. Bioreducible branched polyethyleneimine derivatives physically loaded with hydrophobic pheophorbide A: preparation, characterization, and light-induced cytotoxicity.

    Science.gov (United States)

    Cho, Hana; Li, Li; Bae, You Han; Huh, Kang Moo; Kang, Han Chang

    2014-10-01

    Branched-type hydrophilic polyethyleneimine derivatives (i.e., bPEI derivatives) are developed polymeric carriers for photodynamic therapy. Their chemical structures which contain pH-tunable hydrophobic/hydrophilic cavities enable efficient loading of hydrophobic drugs in basic pH environments. Intracellular stimuli trigger the release of the loaded drugs in bPEI derivatives. As expected, the hydrophobic photosensitizer known as pheophorbide A (PheoA) is solubilized by physical loading in the inner hydrophobic spaces of bPEI derivatives in environments with basic pH values. Interestingly, acidic pH environments induce aggregation, resulting in poor release of the loaded PheoA as well as in quenched photo-activity of the PheoA-loaded polymers. However, when reducible polycation derivatives of bPEI are used (i.e., RPC-bPEI), intracellular thiols degrade the disulfide linkages in the polymers, resulting in rapid PheoA release. Particularly, a RPC-bPEI containing 6 wt% PheoA (i.e., RPC-bPEI(0.8 kDa)-PheoA(6%)) respond remarkably well to light exposure and display large differences between dark toxicity and light-induced toxicity. Cellular uptake of RPC-bPEI(0.8 kDa)-PheoA(6%) is approximately sevenfold to ninefold lower than that of free PheoA. Nevertheless, the photo-toxicity of RPC-bPEI(0.8 kDa)-PheoA(6%) was only two- to sixfold less potent than that of free PheoA. These results suggest that reducible bPEI materials may act as potential solubilizers and carriers for low-molecular-weight hydrophobic anti-cancer drugs.

  5. Preparation and characterization of a novel pH-sensitive hydrogel obtained from UV light-induced polymerization

    Science.gov (United States)

    Tian, R. Q.; Zhao, Y. G.; Cui, Y. Q.; Zhang, X. Y.; Zhang, J.; Liang, X. Y.; Shang, Q.

    2015-05-01

    The main aim of this study was to develop a novel pH-sensitive hydrogel prepared via an UV light-induced polymerization. Single-factor experiments were performed to acquire the optimum formula of final poly(MAA-co-PEGMA) hydrogel. Fourier transform infrared spectroscopy (FTIR) spectra were employed to confirm the successful preparation of the designed copolymers. Inner morphologies of the polymeric hydrogels were observed via an S-4800 scanning electron microscope (SEM). Swelling and reversible swelling-shrinking studies were carried out in different phosphate buffer solution (PBS) with various pH values. Drug-loading tests were performed with bovine serum albumin (BSA) as a model drug. The in vitro release profile was also investigated in PBS with the pH values of 1.2 and 7.4. FTIR spectra confirmed the preparation of the poly(MAA-co-PEGMA) copolymers without any residual monomers. The typical space grid structures were observed from the SEM photographs of hydrogels. The obtained hydrogel showed an excellent pH-sensibility and reversible swelling-shrinking property. The maximum drug-loading (40.9 %) was gained from the BSA concentration of 50.0 mg/mL. During the releasing process, only 5.8 ± 0.9 % of BSA was released at pH 1.2, but 82.1 ± 6.2 % was diffused at pH 7.4. These data suggested that such medicated hydrogel could deliver BSA to alkaline conditions (e.g., intestinal environments) site-specifically, which protected BSA from destroying by gastric acid or pepsase. Therefore, such hydrogel had a significant meaning in theoretical research and practical application.

  6. Light-induced appearance of polysomal poly(A)-rich messenger RNA during greening of barley plants.

    Science.gov (United States)

    Heinze, H; Herzfeld, F; Kiper, M

    1980-10-01

    Changes in polysomal poly(A)-rich mRNA during greening of etiolated barley plants were studied by the technique of cDNA-mRNa hybridization. Hybridizaiton data of the homologous reactions reveal that in etiolated as well as in greened shoots a complexity of 5 X 10(7) nucleotides or about 33000 different average-sized mRNAs are present. These are organized in different abundancy classes with 94% of the total complexicity present in each of the slowest reacting class representing rare messengers. Heterologous hybridizations indicate that 92% of all polysomal poly(A)-rich mRNAs in etiolated shoots are complementary to those of greened and 82% of 'green' poly(A)-rich mRNAs are complementary to white ones. It is shown that the abundant mRNA clases are essentially responsible for these differences. The prevalent classes making up 15% ('white') and 31% ('green') of the poly(A)-rich mRNA mass but comprising only a complexity of 1.8 X 10(4) and 2.1 X 10(4) nucleotides are identical to 50% with each other. Hybridization of isolated prevalent 'green' cDNA with whole 'white' poly(A)-rich mRNA indicates that the additionally appearing 50% prevalent green messengers must be regarded as green-specific, only present in polysomal poly(A)-rich mRNA after illumination. This conclusion is underlined by the hybridization of the 'green' cDNA with total polysomal RNa of etiolated shoots. Evidently appearance of these prevalent messengers in functional polysomes is not caused by a shift from poly(A)-free mRNA to poly(A)-rich mRNA. The results clearly demonstrate that light induces greening by turning on genes or influencing post-transcriptional processing to produce mature green-specific poly(A)-rich mRNA.

  7. A reduced zinc diet or zinc transporter 3 knockout attenuate light induced zinc accumulation and retinal degeneration.

    Science.gov (United States)

    Bai, Shi; Sheline, Carolyn R; Zhou, Yongdong; Sheline, Christian T

    2013-03-01

    Our previous study on retinal light exposure suggests the involvement of zinc (Zn(2+)) toxicity in the death of RPE and photoreceptors (LD) which could be attenuated by pyruvate and nicotinamide, perhaps through restoration of NAD(+) levels. In the present study, we examined Zn(2+) toxicity, and the effects of NAD(+) restoration in primary retinal cultures. We then reduced Zn(2+) levels in rodents by reducing Zn(2+) levels in the diet, or by genetics and measured LD. Sprague Dawley albino rats were fed 2, or 61 mg Zn(2+)/kg of diet for 3 weeks, and exposed to 18 kLux of white light for 4 h. We light exposed (70 kLux of white light for 50 h) Zn(2+) transporter 3 knockout (ZnT3-KO, no synaptic Zn(2+)), or RPE65 knockout mice (RPE65-KO, lack rhodopsin cycling), or C57/BI6/J controls and determined light damage and Zn(2+) staining. Retinal Zn(2+) staining was examined at 1 h and 4 h after light exposure. Retinas were examined after 7 d by optical coherence tomography and histology. After LD, rats fed the reduced Zn(2+) diet showed less photoreceptor Zn(2+) staining and degeneration compared to a normal Zn(2+) diet. Similarly, ZnT3-KO and RPE65-KO mice showed less Zn(2+) staining, NAD(+) loss, and RPE or photoreceptor death than C57/BI6/J control mice. Dietary or ZnT3-dependent Zn(2+) stores, and intracellular Zn(2+) release from rhodopsin recycling are suggested to be involved in light-induced retinal degeneration. These results implicate novel rhodopsin-mediated mechanisms and therapeutic targets for LD. Our companion manuscript demonstrates that pharmacologic, circadian, or genetic manipulations which maintain NAD(+) levels reduce LD.

  8. Enamel demineralization and remineralization under plaque fluid-like conditions: a quantitative light-induced fluorescence study.

    Science.gov (United States)

    Lippert, F; Butler, A; Lynch, R J M

    2011-01-01

    The present study investigated de- and remineralization in enamel lesions under plaque fluid (PF)-like conditions using quantitative light-induced fluorescence (QLF). Preformed lesions were exposed to partially saturated lactic acid solutions, varying in pH and fluoride concentration ([F]) based on a 5 × 3 factorial study design (0/0.1/0.5/1.5/4 ppm F; pH 4.9/5.2/5.5). Average fluorescence loss (ΔF) was monitored for 11 days. Subsequently, lesions were demineralized in a partially saturated acetic acid solution for two 24-hour periods. Data were analyzed using repeated measures analysis of covariance. Lesions exposed to PF at 4 ppm F and pH 5.5 showed not only the most remineralization (ΔΔF = 28.2 ± 14.0%) for all groups after 11 days, but also the most demineralization (ΔΔF = -19.3 ± 13.5%) after subsequent acetic acid exposure. Increased [F] resulted in more remineralization, regardless of pH. Higher pH values resulted in more remineralization. No remineralization was observed in lesions exposed to F-free solutions, regardless of pH. Remineralization was noticeable under the following conditions: pH 4.9 - [F] = 4 ppm, pH 5.2 - [F] ≥ 1.5 ppm, and pH 5.5 - [F] ≥ 0.5 ppm. Overall, [F] had a stronger effect on remineralization than pH. Subsequent demineralization showed that little protection was offered by PF-like solutions, and further demineralization compared with baseline was observed on lesions not remineralized initially. [F] had a stronger effect on net mineral change than pH. The present study has shown that QLF is a valuable tool in studying lesion de- and remineralization under PF-like conditions, where [F] was shown to be more important than pH.

  9. A Neonatal Bimodal MR-CT Head Template

    Science.gov (United States)

    Mohtasebi, Mehrana; Abrishami Moghaddam, Hamid; Grebe, Reinhard; Gity, Masoumeh; Wallois, Fabrice

    2017-01-01

    Neonatal MR templates are appropriate for brain structural analysis and spatial normalization. However, they do not provide the essential accurate details of cranial bones and fontanels-sutures. Distinctly, CT images provide the best contrast for bone definition and fontanels-sutures. In this paper, we present, for the first time, an approach to create a fully registered bimodal MR-CT head template for neonates with a gestational age of 39 to 42 weeks. Such a template is essential for structural and functional brain studies, which require precise geometry of the head including cranial bones and fontanels-sutures. Due to the special characteristics of the problem (which requires inter-subject inter-modality registration), a two-step intensity-based registration method is proposed to globally and locally align CT images with an available MR template. By applying groupwise registration, the new neonatal CT template is then created in full alignment with the MR template to build a bimodal MR-CT template. The mutual information value between the CT and the MR template is 1.17 which shows their perfect correspondence in the bimodal template. Moreover, the average mutual information value between normalized images and the CT template proposed in this study is 1.24±0.07. Comparing this value with the one reported in a previously published approach (0.63±0.07) demonstrates the better generalization properties of the new created template and the superiority of the proposed method for the creation of CT template in the standard space provided by MR neonatal head template. The neonatal bimodal MR-CT head template is freely downloadable from https://www.u-picardie.fr/labo/GRAMFC. PMID:28129340

  10. Equilibrium CO bond lengths

    Science.gov (United States)

    Demaison, Jean; Császár, Attila G.

    2012-09-01

    Based on a sample of 38 molecules, 47 accurate equilibrium CO bond lengths have been collected and analyzed. These ultimate experimental (reEX), semiexperimental (reSE), and Born-Oppenheimer (reBO) equilibrium structures are compared to reBO estimates from two lower-level techniques of electronic structure theory, MP2(FC)/cc-pVQZ and B3LYP/6-311+G(3df,2pd). A linear relationship is found between the best equilibrium bond lengths and their MP2 or B3LYP estimates. These (and similar) linear relationships permit to estimate the CO bond length with an accuracy of 0.002 Å within the full range of 1.10-1.43 Å, corresponding to single, double, and triple CO bonds, for a large number of molecules. The variation of the CO bond length is qualitatively explained using the Atoms in Molecules method. In particular, a nice correlation is found between the CO bond length and the bond critical point density and it appears that the CO bond is at the same time covalent and ionic. Conditions which permit the computation of an accurate ab initio Born-Oppenheimer equilibrium structure are discussed. In particular, the core-core and core-valence correlation is investigated and it is shown to roughly increase with the bond length.

  11. Copper wire bonding

    CERN Document Server

    Chauhan, Preeti S; Zhong, ZhaoWei; Pecht, Michael G

    2014-01-01

    This critical volume provides an in-depth presentation of copper wire bonding technologies, processes and equipment, along with the economic benefits and risks.  Due to the increasing cost of materials used to make electronic components, the electronics industry has been rapidly moving from high cost gold to significantly lower cost copper as a wire bonding material.  However, copper wire bonding has several process and reliability concerns due to its material properties.  Copper Wire Bonding book lays out the challenges involved in replacing gold with copper as a wire bond material, and includes the bonding process changes—bond force, electric flame off, current and ultrasonic energy optimization, and bonding tools and equipment changes for first and second bond formation.  In addition, the bond–pad metallurgies and the use of bare and palladium-coated copper wires on aluminum are presented, and gold, nickel and palladium surface finishes are discussed.  The book also discusses best practices and re...

  12. Tuning the band gap in hybrid tin iodide perovskite semiconductors using structural templating.

    Science.gov (United States)

    Knutson, Jeremy L; Martin, James D; Mitzi, David B

    2005-06-27

    Structural distortions within the extensive family of organic/inorganic hybrid tin iodide perovskite semiconductors are correlated with their experimental exciton energies and calculated band gaps. The extent of the in- and out-of-plane angular distortion of the SnI4(2-) perovskite sheets is largely determined by the relative charge density and steric requirements of the organic cations. Variation of the in-plane Sn-I-Sn bond angle was demonstrated to have the greatest impact on the tuning of the band gap, and the equatorial Sn-I bond distances have a significant secondary influence. Extended Hückel tight-binding band calculations are employed to decipher the crystal orbital origins of the structural effects that fine-tune the band structure. The calculations suggest that it may be possible to tune the band gap by as much as 1 eV using the templating influence of the organic cation.

  13. Relationship between 3-Methyl-2,4-nonanedione Concentration and Intensity of Light-induced Off-odor in Soy Bean Oil.

    Science.gov (United States)

    Sano, Takashi; Iwahashi, Maiko; Imagi, Jun; Sato, Toshiro; Yamashita, Toshiyuki; Fukusaki, Eiichiro; Bamba, Takeshi

    2016-05-01

    A beany and green off-odor is developed in soy bean oil (SBO) under light-induced oxidative conditions. 3-Methyl-2,4-nonanedione (3-MND) was inferred as the compound responsible for the off-odor. In this study, we designed a simple quantification method for 3-MND in SBO, and evaluated the relationship between the 3-MND concentration and the intensity of the off-odor. 3-MND was analyzed by GC/MS with a thermal desorption unit system. By our method, the 3-MND concentration was found to increase with storage days and the SBO content under light exposure, and there was a high correlation between the measured 3-MND concentration and the intensity of the light-induced off-odor in SBO (R = 0.9586).

  14. ApcD is required for state transition but not involved in blue-light induced quenching in the cyanobacterium Anabaena sp. PCC7120

    Institute of Scientific and Technical Information of China (English)

    DONG ChunXia; ZHAO JinDong

    2008-01-01

    Pbycobilisomes (PBS) are able to transfer absorbed energy to photosystem Ⅰ and Ⅱ, and the distribution of light energy between two photosystems is regulated by state transitions. In this study we show that energy transfer from PBS to photosystem Ⅰ (PSI) requires ApcD. Cells were unable to perform state transitions in the absence of ApcD. The apcD mutant grows more slowly in light mainly absorbed by PBS, indicating that ApcD-dependent energy transfer to PSI is required for optimal growth under this condition. The apoD mutant showed normal blue-light induced quenching, suggesting that ApcD is not required for this process and state transitions are independent of blue-light induced quenching. Under nitrogen fixing condition, the growth rates of the wild type and the mutant were the same, indicating that energy transfer from PBS to PSI in heterocysta was not required for nitrogen fixation.

  15. Discussion of dosimetric dependencies of experimental light-induced melatonin suppression studies; Diskussion dosimetrischer Aspekte bei experimentellen Studien zur lichtinduzierten Melatoninreduktion

    Energy Technology Data Exchange (ETDEWEB)

    Weber, M.; Schulmeister, K. [ARC Seibersdorf Research (Austria). Akkreditierte Pruefstelle fuer Laser und Optische Strahlung

    2004-07-01

    Based on a literature review, dosimetric dependencies of light-induced melatonin suppression are discussed. The quantity of light used to suppress melatonin in study trials is often given in terms of illuminance at the cornea, as this is easy to measure. The use of the term illuminance for such studies is critically discussed. A more appropriate measure would be effective irradiance. In our work we present a simplified model to estimate the photobiological effective irradiance and the spot size of the retinal image. Important issues which should ideally be considered in melatonin suppression study trials are pointed out. Another aim of this work is to derive from the literature data, up to what time frame the dosedependent relationship between time and melatonin suppression is valid. An evaluation is made of the situation on the workplace with regard to light-induced melatonin suppression. (orig.)

  16. DNA repair by RNA: Templated, or not templated, that is the question.

    Science.gov (United States)

    Meers, Chance; Keskin, Havva; Storici, Francesca

    2016-08-01

    Cells are continuously exposed to both endogenous and exogenous sources of genomic stress. To maintain chromosome stability, a variety of mechanisms have evolved to cope with the multitude of genetic abnormalities that can arise over the life of a cell. Still, failures to repair these lesions are the driving force of cancers and other degenerative disorders. DNA double-strand breaks (DSBs) are among the most toxic genetic lesions, inhibiting cell ability to replicate, and are sites of mutations and chromosomal rearrangements. DSB repair is known to proceed via two major mechanisms: homologous recombination (HR) and non-homologous end joining (NHEJ). HR reliance on the exchange of genetic information between two identical or nearly identical DNA molecules offers increased accuracy. While the preferred substrate for HR in mitotic cells is the sister chromatid, this is limited to the S and G2 phases of the cell cycle. However, abundant amounts of homologous genetic substrate may exist throughout the cell cycle in the form of RNA. Considered an uncommon occurrence, the direct transfer of information from RNA to DNA is thought to be limited to special circumstances. Studies have shown that RNA molecules reverse transcribed into cDNA can be incorporated into DNA at DSB sites via a non-templated mechanism by NHEJ or a templated mechanism by HR. In addition, synthetic RNA molecules can directly template the repair of DSBs in yeast and human cells via an HR mechanism. New work suggests that even endogenous transcript RNA can serve as a homologous template to repair a DSB in chromosomal DNA. In this perspective, we will review and discuss the recent advancements in DSB repair by RNA via non-templated and templated mechanisms. We will provide current findings, models and future challenges investigating RNA and its role in DSB repair.

  17. Application of quantitative light-induced fluorescence to determine the depth of demineralization of dental fluorosis in enamel microabrasion: a case report

    OpenAIRE

    PARK, Tae-Young; Choi, Han-Sol; Ku, Hee-Won; Kim, Hyun-Su; Lee, Yoo-Jin; Min, Jeong-Bum

    2016-01-01

    Enamel microabrasion has become accepted as a conservative, nonrestorative method of removing intrinsic and superficial dysmineralization defects from dental fluorosis, restoring esthetics with minimal loss of enamel. However, it can be difficult to determine if restoration is necessary in dental fluorosis, because the lesion depth is often not easily recognized. This case report presents a method for analysis of enamel hypoplasia that uses quantitative light-induced fluorescence (QLF) follow...

  18. In situ visualizing the evolution of the light-induced refractive index change of Mn:KLTN crystal with digital holographic interferometry

    OpenAIRE

    Jinxin Han; Qieni Lu; Haitao Dai; Shuang Zhao; Yimo Zhang

    2015-01-01

    The light-induced refractive index change in Mn:KLTN crystal, illuminated by focused light sheet, is visualized in situ and quantified by digital holographic interferometry. By numerically retrieving a series of sequential phase maps from recording digital holograms, the spatial distribution of the induced refractive index change can be visualized and estimated readily. This technique enables the observation of the temporal evolution of the refractive index change under different recording si...

  19. Synchrotron radiation structure analyses of the light-induced radical pair of a hexaarylbiimidazolyl derivative. Origin of the spin-multiplicity change

    CERN Document Server

    Kawano, M; Matsubara, K; Imabayashi, H; Mitsumi, M; Toriumi, K; Ohashi, Y

    2002-01-01

    In situ synchrotron radiation structure analyses of a light-induced radical pair from o-Cl-HABI were performed by using an X-ray vacuum camera at 23-70K at the BL02B1 station of SPring-8. The combined results of X-ray analysis with theoretical calculation, IR, and UV-vis spectroscopy reveal that a slight conformational change of the radical pair causes the drastic spin-multiplicity change during 2-140K. (author)

  20. Comparison of Gold Bonding with Mercury Bonding

    NARCIS (Netherlands)

    Kraka, Elfi; Filatov, Michael; Cremer, Dieter

    2009-01-01

    Nine AuX molecules (X = H, O, S, Se, Te, F, Cl, Br, I), their isoelectronic HgX(+) analogues, and the corresponding neutral HgX diatomics have been investigated using NESC (Normalized Elimination of the Small Component) and B3LYP theory to determine relativistic effects for bond dissociation energie

  1. Ear Authentication and Template Protection using Bio-key

    Directory of Open Access Journals (Sweden)

    K. Annapurani

    2014-09-01

    Full Text Available Biometric authentication is gaining popularity in the current scenario. Biometric based authentication is the science of using physical or behavioral characteristic for ensuring that the person is the claimed identity. Biometric authentication system is also vulnerable to attacks in various phases. The biometric data stored in the template has to be protected, since variety of attacks like circumvent, covert acquisition affects the normal functioning of the system. An attacker may create new biometric data or steal the template or modify the template. Once the biometric template is compromised then the entire system is lost. So securing biometric template is an important aspect in biometric authentication system. In this study ear biometric template is secured by a new method of generating bio key from the ear fused template. Here the transformed template is stored in the database. During verification phase, for the new biometric sample a bio key is generated. Using this bio key the person is authenticated if the transformed feature generated is matched with the stored one. Hence the template is protected with the bio key. The authenticated person alone can access the system, since the key to decrypt the encrypted template is obtained from the ear trait of the authenticated person. FAR and FRR are used to evaluate the system performance.

  2. A highly efficient TiO(2-x)C(x) nano-heterojunction photocatalyst for visible light induced antibacterial applications.

    Science.gov (United States)

    Etacheri, Vinodkumar; Michlits, Georg; Seery, Michael K; Hinder, Steven J; Pillai, Suresh C

    2013-03-13

    Visible-light-induced antibacterial activity of carbon-doped anatase-brookite titania nano-heterojunction photocatalysts are reported for the first time. These heterostructures were prepared using a novel low temperature (100 °C) nonhydrothermal low power microwave (300 W) assisted method. Formation of interband C 2p states was found to be responsible for the band gap narrowing of the carbon doped heterojunctions. The most active photocatalyst obtained after 60 min of microwave irradiation exhibits a 2-fold higher visible-light induced photocatalytic activity in contrast to the standard commercial photocatalyst Evonik-Degussa P-25. Staphylococcus aureus inactivation rate constant for carbon-doped nano-heterojunctions and the standard photocatalyst was 0.0023 and -0.0081 min(-1), respectively. It is proposed that the photoexcited electrons (from the C 2p level) are effectively transferred from the conduction band of brookite to that of anatase causing efficient electron-hole separation, which is found to be responsible for the superior visible-light induced photocatalytic and antibacterial activities of carbon-doped anatase-brookite nano-heterojunctions.

  3. The dissociative bond.

    Science.gov (United States)

    Gordon, Nirit

    2013-01-01

    Dissociation leaves a psychic void and a lingering sense of psychic absence. How do 2 people bond while they are both suffering from dissociation? The author explores the notion of a dissociative bond that occurs in the aftermath of trauma--a bond that holds at its core an understanding and shared detachment from the self. Such a bond is confined to unspoken terms that are established in the relational unconscious. The author proposes understanding the dissociative bond as a transitional space that may not lead to full integration of dissociated knowledge yet offers some healing. This is exemplified by R. Prince's (2009) clinical case study. A relational perspective is adopted, focusing on the intersubjective aspects of a dyadic relationship. In the dissociative bond, recognition of the need to experience mutual dissociation can accommodate a psychic state that yearns for relationship when the psyche cannot fully confront past wounds. Such a bond speaks to the need to reestablish a sense of human relatedness and connection when both parties in the relationship suffer from disconnection. This bond is bound to a silence that becomes both a means of protection against the horror of traumatic memory and a way to convey unspoken gestures toward the other.

  4. The samurai bond market

    OpenAIRE

    1997-01-01

    Issuance in the samurai bond market has more than tripled over the past several years. Some observers have attributed this growth to a systematic underestimation of credit risk in the market. A detailed review of credit quality, ratings differences, and initial issue pricing in the samurai bond market, however, turns up little evidence to support this concern.

  5. Multistate APLIP and VibLIP: From molecular bond extension to atomic transport

    CERN Document Server

    Suominen, Kalle-Antti

    2013-01-01

    APLIP is a method for using a STIRAP-like three-state configuration with two laser pulses for continuous extension of a molecular bond, introduced in 1998. It is based on time-dependent light-induced potential surfaces (LIP). In VibLIP one extends the idea into a method for tailoring the vibrational state while changing the electronic state, introduced in 2000. Here I discuss the extension of both methods to situations that involve more than three electronic states, and note the possibility of using the method on adiabatic transport of atoms between microtraps or equivalent structures.

  6. Light induced E-Z isomerization in a multi-responsive organogel: elucidation from (1)H NMR spectroscopy.

    Science.gov (United States)

    Mondal, Sanjoy; Chakraborty, Priyadarshi; Bairi, Partha; Chatterjee, Dhruba P; Nandi, Arun K

    2015-07-07

    A multiresponsive organogel of (E)-N'-(anthracene-10-ylmethylene)-3,4,5-tris(dodecyloxy)benzohydrazide (I) showed a decrease of fluorescence intensity, decrease in mechanical strength and a change in gel morphology on irradiation with a wavelength of 365 nm. This is attributed to the E-Z isomerization across the C=N bond of I as evidenced from (1)H NMR spectroscopy.

  7. The Contextualization of Archetypes: Clinical Template Governance.

    Science.gov (United States)

    Pedersen, Rune; Ulriksen, Gro-Hilde; Ellingsen, Gunnar

    2015-01-01

    This paper is a status report from a large-scale openEHR-based EPR project from the North Norway Regional Health Authority. It concerns the standardization of a regional ICT portfolio and the ongoing development of a new process oriented EPR systems encouraged by the unfolding of a national repository for openEHR archetypes. Subject of interest; the contextualization of clinical templates is governed over multiple national boundaries which is complex due to the dependency of clinical resources. From the outset of this, we are interested in how local, regional, and national organizers maneuver to standardize while applying OpenEHR technology.

  8. Progress of UV-NIL template making

    Science.gov (United States)

    Hiraka, Takaaki; Mizuochi, Jun; Nakanishi, Yuko; Yusa, Satoshi; Sasaki, Shiho; Morikawa, Yasutaka; Mohri, Hiroshi; Hayashi, Naoya

    2009-04-01

    Nano-imprint lithography (NIL) has been counted as one of the lithography candidates for hp32nm node and beyond and has showed excellent resolution capability with remarkable low line edge roughness that is attracting many researchers in the industry who were searching for the finest patterning technology. Therefore, recently we have been focusing on the resolution improvement on the NIL templates with the 100keV acceleration voltage spot beam (SB) EB writer and the 50keV acceleration voltage variable shaped beam (VSB) EB writer. The 100keV SB writers have high resolution capability, but they show fatally low throughput if we need full chip writing. Usually templates for resolution pioneers needed just a small field (several hundred microns square or so), but recently requirements for full chip templates are increasing. For full chip writing, we have also started the resolution improvement with the 50keV VSB writers used in current 4X photomask manufacturing. The 50keV VSB writers could generate full chip pattern in a reasonable time though resolution limits are inferior to that with the 100keV SB writers. In this paper, we will show latest results with both the 100keV SB and the 50keV VSB EB writers. With the 100keV SB EB writer, we have achieved down to hp15nm resolution for line and space pattern, but found that to achieve further improvement, an innovation in pattern generation method or material would be inevitable. With the 50keV VSB EB writer, we have achieved down to hp22nm resolution for line and space pattern. Though NIL has excellent resolution capability, solutions for defect inspection and repair are not clearly shown yet. In this paper, we will show preliminary inspection results with an EB inspection tool. We tested an EB inspection tool by Hermes Microvision, Inc. (HMI), which was originally developed for and are currently used as a wafer inspection tool, and now have been started to seek the application for mask use, using a programmed defect

  9. Template-directed porous electrodes in electroanalysis.

    Science.gov (United States)

    Walcarius, Alain

    2010-01-01

    Nano- and/or macrostructuring of electrode surfaces has recently emerged as a powerful method of improving the performances of electrochemical devices by enhancing both molecular accessibility and rapid mass transport via diffusion, by increasing the electroactive surface area in comparison to the geometric one, and/or by providing confinement platforms for hosting suitable reagents. This brief overview highlights how template technology offers advantages in terms of designing new types of porous electrodes-mostly based on thin films, and functionalized or not-and discusses their use in analytical chemistry via some recent examples from the literature on electrochemical sensors and biosensors.

  10. Exploring aromatic chemical space with NEAT: novel and electronically equivalent aromatic template.

    Science.gov (United States)

    Tu, Meihua; Rai, Brajesh K; Mathiowetz, Alan M; Didiuk, Mary; Pfefferkorn, Jeffrey A; Guzman-Perez, Angel; Benbow, John; Guimarães, Cristiano R W; Mente, Scot; Hayward, Matthew M; Liras, Spiros

    2012-05-25

    In this paper, we describe a lead transformation tool, NEAT (Novel and Electronically equivalent Aromatic Template), which can help identify novel aromatic rings that are estimated to have similar electrostatic potentials, dipoles, and hydrogen bonding capabilities to a query template; hence, they may offer similar bioactivity profiles. In this work, we built a comprehensive heteroaryl database, and precalculated high-level quantum mechanical (QM) properties, including electrostatic potential charges, hydrogen bonding ability, dipole moments, chemical reactivity, and othe properties. NEAT bioisosteric similarities are based on the electrostatic potential surface calculated by Brood, using the precalculated QM ESP charges and other QM properties. Compared with existing commercial lead transformation software, (1) NEAT is the only one that covers the comprehensive heteroaryl chemical space, and (2) NEAT offers a better characterization of novel aryl cores by using high-evel QM properties that are relevant to molecular interactions. NEAT provides unique value to medicinal chemists quickly exploring the largely uncharted aromatic chemical space, and one successful example of its application is discussed herein.

  11. A New Vectorization Technique for Expression Templates in C++

    CERN Document Server

    Progsch, J; Adelmann, A

    2011-01-01

    Vector operations play an important role in high performance computing and are typically provided by highly optimized libraries that implement the BLAS (Basic Linear Algebra Subprograms) interface. In C++ templates and operator overloading allow the implementation of these vector operations as expression templates which construct custom loops at compile time and providing a more abstract interface. Unfortunately existing expression template libraries lack the performance of fast BLAS(Basic Linear Algebra Subprograms) implementations. This paper presents a new approach - Statically Accelerated Loop Templates (SALT) - to close this performance gap by combining expression templates with an aggressive loop unrolling technique. Benchmarks were conducted using the Intel C++ compiler and GNU Compiler Collection to assess the performance of our library relative to Intel's Math Kernel Library as well as the Eigen template library. The results show that the approach is able to provide optimization comparable to the fas...

  12. Observers change their target template based on expected context.

    Science.gov (United States)

    Bravo, Mary J; Farid, Hany

    2016-04-01

    Previous studies have shown that when observers search repeatedly for a target in a particular context, they may develop a target template that is biased for that context. Because the same target may appear in multiple contexts, we wondered whether observers are able to develop multiple templates for the same target, with each template biased for a particular context. In a series of behavioral experiments, we show that observers can learn multiple target templates for a single target and that they can voluntarily switch among these templates depending on the context they expect to see. Our results suggest that these biased templates may coexist with an unbiased representation of the target, provided they are learned first.

  13. Silicon template preparation for the fabrication of thin patterned gold films via template stripping

    Science.gov (United States)

    Schmidl, G.; Dellith, J.; Dellith, A.; Teller, N.; Zopf, D.; Li, G.; Dathe, A.; Mayer, G.; Hübner, U.; Zeisberger, M.; Stranik, O.; Fritzsche, W.

    2015-12-01

    Metallic nanostructures play an important role in the vast field of modern nanophotonics, which ranges from the life sciences to biomedicine and beyond. Gold is a commonly-used and attractive material for plasmonics in the visible wavelength range, most importantly due to its chemical stability. In the present work, we focused on the different methods of plasmonic nanostructure fabrication that possess the greatest potential for cost-efficient fabrication. Initially, reusable (1 0 0) silicon templates were prepared. For this purpose, three different lithography methods (i.e. e-beam, optical, and nanoparticle lithography) were used that correspond to the desired structural scales. The application of a subsequent anisotropic crystal orientation-dependent wet etching process produced well-defined pyramidal structures in a wide variety of sizes, ranging from several microns to less than 100 nm. Finally, a 200 nm-thick gold layer was deposited by means of confocal sputtering on the silicon templates and stripped in order to obtain gold films that feature a surface replica of the initial template structure. The surface roughness that was achieved on the stripped films corresponds well with the roughness of the template used. This makes it possible to prepare cost-efficient high-quality structured films in large quantities with little effort. The gold films produced were thoroughly characterized, particularly with respect to their plasmonic response.

  14. A nanocluster beacon based on the template transformation of DNA-templated silver nanoclusters.

    Science.gov (United States)

    Teng, Ye; Jia, Xiaofang; Zhang, Shan; Zhu, Jinbo; Wang, Erkang

    2016-01-28

    In this work, we developed a novel light-up nanocluster beacon (NCB) based on shuttling dark silver nanoclusters (NCs) to a bright scaffold through hybridization. The fluorescence enhancement was as high as 70-fold when the two templates were on the opposite sides of the duplexes, enabling sensitive and selective detection of DNA.

  15. Novel encoding methods for DNA-templated chemical libraries.

    Science.gov (United States)

    Li, Gang; Zheng, Wenlu; Liu, Ying; Li, Xiaoyu

    2015-06-01

    Among various types of DNA-encoded chemical libraries, DNA-templated library takes advantage of the sequence-specificity of DNA hybridization, enabling not only highly effective DNA-templated chemical reactions, but also high fidelity in library encoding. This brief review summarizes recent advances that have been made on the encoding strategies for DNA-templated libraries, and it also highlights their respective advantages and limitations for the preparation of DNA-encoded libraries.

  16. Delicate balance of hydrogen bonding forces in D-threoninol.

    Science.gov (United States)

    Vaquero-Vara, Vanesa; Zhang, Di; Dian, Brian C; Pratt, David W; Zwier, Timothy S

    2014-09-01

    The seven most stable conformers of D-threoninol (2(S)-amino-1,3(S)-butanediol), a template used for the synthesis of artificial nucleic acids, have been identified and characterized from their pure rotational transitions in the gas phase using chirped-pulse Fourier transform microwave spectroscopy. D-Threoninol is a close analogue of glycerol, differing by substitution of an NH2 group for OH on the C(β) carbon and by the presence of a terminal CH3 group that breaks the symmetry of the carbon framework. Of the seven observed structures, two are H-bonded cycles containing three H-bonds that differ in the direction of the H-bonds in the cycle. The other five are H-bonded chains containing OH···NH···OH H-bonds with different directions along the carbon framework and different dihedral angles along the chain. The two structural types (cycles and chains of H-bonds) are in surprisingly close energetic proximity. Comparison of the rotational constants with the calculated structures at the MP2/6-311++G(d,p) level of theory reveals systematic changes in the H-bond distances that reflect NH2 as a better H-bond acceptor and poorer donor, shrinking the H-bond distances by ∼0.2 Å in the former case and lengthening them by a corresponding amount in the latter. Thus revealed is the subtle effect of asymmetric substitution on the energy landscape of a simple molecule, likely to be important in living systems.

  17. Effect of ultrasonic power and bonding force on the bonding strength of copper ball bonds

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Copper wire, serving as a cost-saving alternative to gold wire, has been used in many high-end thermosonic ball bonding applications. In this paper, the bond shear force, bond shear strength, and the ball bond diameter are adopted to evaluate the bonding quality. It is concluded that the efficient ultrasonic power is needed to soften the ball to form the copper bonds with high bonding strength. However, excessive ultrasonic power would serve as a fatigue loading to weaken the bonding. Excessive or less bonding force would cause cratering in the silicon.

  18. Transversely Compressed Bonded Joints

    DEFF Research Database (Denmark)

    Hansen, Christian Skodborg; Schmidt, Jacob Wittrup; Stang, Henrik

    2012-01-01

    The load capacity of bonded joints can be increased if transverse pressure is applied at the interface. The transverse pressure is assumed to introduce a Coulomb-friction contribution to the cohesive law for the interface. Response and load capacity for a bonded single-lap joint was derived using...... non-linear fracture mechanics. The results indicated a good correlation between theory and tests. Furthermore, the model is suggested as theoretical base for determining load capacity of bonded anchorages with transverse pressure, in externally reinforced concrete structures....

  19. Flowerlike PtCl 4/Bi 2WO 6 composite photocatalyst with enhanced visible-light-induced photocatalytic activity

    Science.gov (United States)

    Duan, Fang; Zheng, Yan; Chen, MingQing

    2011-01-01

    Flowerlike PtCl 4/Bi 2WO 6 composite photocatalyst was successfully synthesized through a simple two-step method involving a template-free hydrothermal process and the following impregnation treatment. The samples were fully characterized by the study of X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), and UV-Vis absorption spectra. The results indicated that the doping of Pt species did not affect the crystal structure and the morphology of Bi 2WO 6 photocatalyst, but it had great influences on the photocatalytic activity of Bi 2WO 6 towards rhodamine-B (RhB) degradation. Besides, the Pt species was found to be present as PtCl 4 in the composite samples, and also an optimal Pt species content on the surface of Bi 2WO 6 photocatalyst was discovered with the highest photocatalytic ability. The improved photocatalytic performance could be ascribed to the enhanced interfacial charge transfer and the inhibited recombination of electron-hole pairs. Meanwhile, a possible mechanism for RhB photocatalytic degradation over PtCl 4/Bi 2WO 6 catalyst was also proposed.

  20. Handbook of wafer bonding

    CERN Document Server

    Ramm, Peter; Taklo, Maaike M V

    2011-01-01

    Written by an author and editor team from microsystems companies and industry-near research organizations, this handbook and reference presents dependable, first-hand information on bonding technologies.In the first part, researchers from companies and institutions around the world discuss the most reliable and reproducible technologies for the production of bonded wafers. The second part is devoted to current and emerging applications, including microresonators, biosensors and precise measuring devices.

  1. Interplay of I-TASSER and QUARK for template-based and ab initio protein structure prediction in CASP10.

    Science.gov (United States)

    Zhang, Yang

    2014-02-01

    We develop and test a new pipeline in CASP10 to predict protein structures based on an interplay of I-TASSER and QUARK for both free-modeling (FM) and template-based modeling (TBM) targets. The most noteworthy observation is that sorting through the threading template pool using the QUARK-based ab initio models as probes allows the detection of distant-homology templates which might be ignored by the traditional sequence profile-based threading alignment algorithms. Further template assembly refinement by I-TASSER resulted in successful folding of two medium-sized FM targets with >150 residues. For TBM, the multiple threading alignments from LOMETS are, for the first time, incorporated into the ab initio QUARK simulations, which were further refined by I-TASSER assembly refinement. Compared with the traditional threading assembly refinement procedures, the inclusion of the threading-constrained ab initio folding models can consistently improve the quality of the full-length models as assessed by the GDT-HA and hydrogen-bonding scores. Despite the success, significant challenges still exist in domain boundary prediction and consistent folding of medium-size proteins (especially beta-proteins) for nonhomologous targets. Further developments of sensitive fold-recognition and ab initio folding methods are critical for solving these problems.

  2. Image Hashes as Templates for Verification

    Energy Technology Data Exchange (ETDEWEB)

    Janik, Tadeusz; Jarman, Kenneth D.; Robinson, Sean M.; Seifert, Allen; McDonald, Benjamin S.; White, Timothy A.

    2012-07-17

    Imaging systems can provide measurements that confidently assess characteristics of nuclear weapons and dismantled weapon components, and such assessment will be needed in future verification for arms control. Yet imaging is often viewed as too intrusive, raising concern about the ability to protect sensitive information. In particular, the prospect of using image-based templates for verifying the presence or absence of a warhead, or of the declared configuration of fissile material in storage, may be rejected out-of-hand as being too vulnerable to violation of information barrier (IB) principles. Development of a rigorous approach for generating and comparing reduced-information templates from images, and assessing the security, sensitivity, and robustness of verification using such templates, are needed to address these concerns. We discuss our efforts to develop such a rigorous approach based on a combination of image-feature extraction and encryption-utilizing hash functions to confirm proffered declarations, providing strong classified data security while maintaining high confidence for verification. The proposed work is focused on developing secure, robust, tamper-sensitive and automatic techniques that may enable the comparison of non-sensitive hashed image data outside an IB. It is rooted in research on so-called perceptual hash functions for image comparison, at the interface of signal/image processing, pattern recognition, cryptography, and information theory. Such perceptual or robust image hashing—which, strictly speaking, is not truly cryptographic hashing—has extensive application in content authentication and information retrieval, database search, and security assurance. Applying and extending the principles of perceptual hashing to imaging for arms control, we propose techniques that are sensitive to altering, forging and tampering of the imaged object yet robust and tolerant to content-preserving image distortions and noise. Ensuring that the

  3. Network Topology Inference from Spectral Templates

    CERN Document Server

    Segarra, Santiago; Mateos, Gonzalo; Ribeiro, Alejandro

    2016-01-01

    We address the problem of identifying a graph structure from the observation of signals defined on its nodes. Fundamentally, the unknown graph encodes direct relationships between signal elements, which we aim to recover from observable indirect relationships generated by a diffusion process on the graph. The fresh look advocated here permeates benefits from convex optimization and stationarity of graph signals, in order to identify the graph shift operator (a matrix representation of the graph) given only its eigenvectors. These spectral templates can be obtained, e.g., from the sample covariance of independent graph signals diffused on the sought network. The novel idea is to find a graph shift that, while being consistent with the provided spectral information, endows the network with certain desired properties such as sparsity. To that end we develop efficient inference algorithms stemming from provably-tight convex relaxations of natural nonconvex criteria, particularizing the results for two shifts: the...

  4. Using archetypes for defining CDA templates.

    Science.gov (United States)

    Moner, David; Moreno, Alberto; Maldonado, José A; Robles, Montserrat; Parra, Carlos

    2012-01-01

    While HL7 CDA is a widely adopted standard for the documentation of clinical information, the archetype approach proposed by CEN/ISO 13606 and openEHR is gaining recognition as a means of describing domain models and medical knowledge. This paper describes our efforts in combining both standards. Using archetypes as an alternative for defining CDA templates permit new possibilities all based on the formal nature of archetypes and their ability to merge into the same artifact medical knowledge and technical requirements for semantic interoperability of electronic health records. We describe the process followed for the normalization of existing legacy data in a hospital environment, from the importation of the HL7 CDA model into an archetype editor, the definition of CDA archetypes and the application of those archetypes to obtain normalized CDA data instances.

  5. Pattern formation in nanoporous titania templates.

    Science.gov (United States)

    Richter, C; Wu, Z; Menon, L

    2007-02-01

    We have carried out a systematic investigation into the formation of nanoscaled patterns in titania (TiO2) templates under dc anodization of Ti in HF acid. At lower acid concentrations (around 0.5 wt% HF) either pores or tubes form at the surface of anodized titanium foil. The pores or nanotubes are separated from the bottom Ti layer by a thin barrier layer of TiO2. The critical voltage where the transition from pores to tubes occurs has been determined. It is observed that the transition voltage shift towards higher voltages as acid concentration is increased, with pore formation disappearing altogether at high acid concentrations. We have also carried out a systematic investigation into the dependence of pore and tube parameters on the applied dc anodization voltage. Our results indicate that the barrier layer thickness, pore and tube length increase as a function of applied voltage.

  6. Virus Assemblies as Templates for Nanocircuits

    Energy Technology Data Exchange (ETDEWEB)

    James N Culver; Michael T Harris

    2011-08-31

    The goals of this project were directed at the identification and characterization of bio-mineralization processes and patterning methods for the development of nano scale materials and structures with novel energy and conductive traits. This project utilized a simple plant virus as a model template to investigate methods to attach and coat metals and other inorganic compounds onto biologically based nanotemplates. Accomplishments include: the development of robust biological nanotemplates with enhanced inorganic coating activities; novel coating strategies that allow for the deposition of a continuous inorganic layer onto a bio-nanotemplate even in the absence of a reducing agent; three-dimensional patterning methods for the assemble of nano-featured high aspect ratio surfaces and the demonstrated use of these surfaces in enhancing battery and energy storage applications. Combined results from this project have significantly advanced our understanding and ability to utilize the unique self-assembly properties of biologically based molecules to produce novel materials at the nanoscale level.

  7. Automated spectral classification using template matching

    Institute of Scientific and Technical Information of China (English)

    Fu-Qing Duan; Rong Liu; Ping Guo; Ming-Quan Zhou; Fu-Chao Wu

    2009-01-01

    An automated spectral classification technique for large sky surveys is pro-posed. We firstly perform spectral line matching to determine redshift candidates for an observed spectrum, and then estimate the spectral class by measuring the similarity be-tween the observed spectrum and the shifted templates for each redshift candidate. As a byproduct of this approach, the spectral redshift can also be obtained with high accuracy. Compared with some approaches based on computerized learning methods in the liter-ature, the proposed approach needs no training, which is time-consuming and sensitive to selection of the training set. Both simulated data and observed spectra are used to test the approach; the results show that the proposed method is efficient, and it can achieve a correct classification rate as high as 92.9%, 97.9% and 98.8% for stars, galaxies and quasars, respectively.

  8. Biologically Inspired Flagella-Templated Silica Nanotubes

    Science.gov (United States)

    Jo, Wonjin

    The desire and need for various types of nanostructures have been met with challenges of feasibility, reproducibility, and long fabrication time. To work towards improved bottom-up methods of nanofabrication, bacterial flagella are particularly attractive bio-templates for nanotubes due to their tubular structures and small inner and outer diameters. In this work, flagella isolated from Salmonella typhimurium are used as bio-templates to fabricate silica mineralized nanotubes. The process involves as well-controlled hydrolysis and condensation reaction with aminopropyltriethoxysilane (APTES), followed by the addition of tetraethoxysilane (TEOS). By controlling the concentration of TEOS and the reaction time, a simple and precise method is developed for creating silica-mineralized flagella nanotubes (SMFNs) with various thicknesses of the silica layer. In addition, the SMFNs are further modified to multifunctional nanotubes by coating metal nanoparticles (NPs) or metal oxide NPs such as gold, palladium, and iron oxide. The metallized SMFNs are achieved through reactions including reductive metallization or oxidative hydrolysis. The results from these studies provide evidence for the complete coating of SMFNs with uniform metal NP sizes and high surface area coverage. The metallized SMFNs are found to be electrically conductive along their network structures. The current-voltage characteristics show remarkably improved electrical conductivities depending on the types of metal NPs loading and SMFN networks concentration. The biologically inspired SMFNs with metal loading will allow have controlled electrical properties that can lead to the potential of creating unique and precise nanoelectronic materials. Lastly, the randomly entangled SMFNs are characterized to demonstrate their capabilities for hydrophilic and hydrophobic surface applications.

  9. The Applicability of Interactive Item Templates in Varied Knowledge Types

    Science.gov (United States)

    Koong, Chorng-Shiuh; Wu, Chi-Ying

    2011-01-01

    A well-edited assessment can enhance student's learning motives. Applicability of items, which includes item content and template, plays a crucial role in authoring a good assessment. Templates in discussion contain not only conventional true & false, multiple choice, completion item and short answer but also of those interactive ones. Methods…

  10. Design of a process template for amine synthesis

    DEFF Research Database (Denmark)

    Singh, Ravendra; Godfrey, Andy; Gregertsen, Björn;

    A conceptual nitro reduction process template that should be generic such that it can handle a series of substrates with sim ilar molecular functionality has been designed. The reduction process is based on a continuo us plug-flow slurry reactor. The process template aims at speeding up the process...

  11. Rapid prototyping drill guide template for lumbar pedicle screw placement

    Institute of Scientific and Technical Information of China (English)

    LU Sheng; XU Yong-qing; ZHANG Yuan-zhi; LI Yan-bing; SHI Ji-hong; CHEN Guo-ping; CHEN Yu-bing

    2009-01-01

    To develop a novel method of spinal pedical stereotaxy by reverse engineering and rapid prototyping techniques, and to validate its accuracy by experimental and clinical studies. Methods: A 3D reconstruction model for the desired lumbar vertebra was generated by using the Mimics 10.11 software, and the optimal screw size and orientation were determined using the reverse engineering software. Afterwards, a drill template was created by reverse engi-neering principle, whose surface was the antitemplate of the vertebral surface. The drill template and its correspond-ing vertebra were manufactured using the rapid prototyping technique. Results: The accuracy of the drill template was con-firmed by drilling screw trajectory into the vertebral biomodel preoperatively. This method also showed its ability to cus-tomize the placement and size of each screw based on the unique morphology of the lumbar vertebra.The drill tem-plate fits the postural surface of the vertebra very well in the cadaver experiment. Postoperative CT scans for controlling the pedicle bore showed that the personalized template had a high precision in cadaver experiment and clinical application. No misplacement occurred by using the per-sonalized template. During surgery, no additional computer assistance was needed.Conclusions: The authors have developed a novel drill template for lumbar pedicle screw placement with good applicability and high accuracy. The potential use of drill templates to place lumbar pedicle screws is promising. Our methodology appears to provide an accurate technique and trajectory for pedicle screw placement in the lumbar spine.

  12. Zeta-functions of renormalizable sub-Lorenz templates

    Energy Technology Data Exchange (ETDEWEB)

    Franco, Nuno, E-mail: nmf@uevora.p [CIMA-UE and Department of Mathematics, University of Evora, Rua Romao Ramalho, 59, 7000-671 Evora (Portugal); Silva, Luis, E-mail: lfs@dec.isel.ipl.p [CIMA-UE and Scientific Area of Mathematics, Instituto Superior de Engenharia de Lisboa, Rua Conselheiro Emidio Navarro, 1, 1959-007 Lisboa (Portugal)

    2010-12-15

    We describe the Williams zeta-functions and the twist zeta-functions of sub-Lorenz templates generated by renormalizable Lorenz maps, in terms of the corresponding zeta-functions of the sub-Lorenz templates generated by the renormalized map and by the map that determines the renormalization type.

  13. Computer-Aided Template for Model Reuse, Development and Maintenance

    DEFF Research Database (Denmark)

    Fedorova, Marina; Sin, Gürkan; Gani, Rafiqul

    2014-01-01

    A template-based approach for model development is presented in this work. Based on a model decomposition technique, the computer-aided template concept has been developed. This concept is implemented as a software tool , which provides a user-friendly interface for following the workflow steps, ...

  14. Arabidopsis FHY3 and FAR1 Regulate Light-Induced myo-Inositol Biosynthesis and Oxidative Stress Responses by Transcriptional Activation of MIPS1.

    Science.gov (United States)

    Ma, Lin; Tian, Tian; Lin, Rongcheng; Deng, Xing-Wang; Wang, Haiyang; Li, Gang

    2016-04-04

    myo-Inositol-1-phosphate synthase (MIPS) catalyzes the limiting step of inositol biosynthesis and has crucial roles in plant growth and development. In response to stress, the transcription of MIPS1 is induced and the biosynthesis of inositol or inositol derivatives is promoted by unknown mechanisms. Here, we found that the light signaling protein FAR-RED ELONGATED HYPOCOTYL3 (FHY3) and its homolog FAR-RED IMPAIRED RESPONSE1 (FAR1) regulate light-induced inositol biosynthesis and oxidative stress responses by activating the transcription of MIPS1. Disruption of FHY3 and FAR1 caused light-induced cell death after dark-light transition, precocious leaf senescence, and increased sensitivity to oxidative stress. Reduction of salicylic acid (SA) accumulation by overexpression of SALICYLIC ACID 3-HYDROXYLASE largely suppressed the cell death phenotype of fhy3 far1 mutant plants, suggesting that FHY3- and FAR1-mediated cell death is dependent on SA. Furthermore, comparative analysis of chromatin immunoprecipitation sequencing and microarray results revealed that FHY3 and FAR1 directly target both MIPS1 and MIPS2. The fhy3 far1 mutant plants showed severely decreased MIPS1/2 transcript levels and reduced inositol levels. Conversely, constitutive expression of MIPS1 partially rescued the inositol contents, caused reduced transcript levels of SA-biosynthesis genes, and prevented oxidative stress in fhy3 far1. Taken together, our results indicate that the light signaling proteins FHY3 and FAR1 directly bind the promoter of MIPS1 to activate its expression and thereby promote inositol biosynthesis to prevent light-induced oxidative stress and SA-dependent cell death.

  15. Light-Induced Movements of Chloroplasts and Nuclei Are Regulated in Both Cp-Actin-Filament-Dependent and -Independent Manners in Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Noriyuki Suetsugu

    Full Text Available Light-induced chloroplast movement and attachment to the plasma membrane are dependent on actin filaments. In Arabidopsis thaliana, the short actin filaments on the chloroplast envelope, cp-actin filaments, are essential for chloroplast movement and positioning. Furthermore, cp-actin-filament-mediated chloroplast movement is necessary for the strong-light-induced nuclear avoidance response. The proteins CHLOROPLAST UNUSUAL POSITIONING 1 (CHUP1, KINESIN-LIKE PROTEIN FOR ACTIN-BASED CHLOROPLAST MOVEMENT 1 (KAC1 and KAC2 are required for the generation and/or maintenance of cp-actin filaments in Arabidopsis. In land plants, CHUP1 and KAC family proteins play pivotal roles in the proper movement of chloroplasts and their attachment to the plasma membrane. Here, we report similar but distinct phenotypes in chloroplast and nuclear photorelocation movements between chup1 and kac1kac2 mutants. Measurement of chloroplast photorelocation movement indicated that kac1kac2, but not chup1, exhibited a clear strong-light-induced increase in leaf transmittance changes. The chloroplast movement in kac1kac2 depended on phototropin 2, CHUP1 and two other regulators for cp-actin filaments, PLASTID MOVEMENT IMPAIRED 1 and THRUMIN 1. Furthermore, kac1kac2 retained a weak but significant nuclear avoidance response although chup1 displayed a severe defect in the nuclear avoidance response. The kac1kac2chup1 triple mutant was completely defective in both chloroplast and nuclear avoidance responses. These results indicate that CHUP1 and the KACs function somewhat independently, but interdependently mediate both chloroplast and nuclear photorelocation movements.

  16. Light-Induced Movements of Chloroplasts and Nuclei Are Regulated in Both Cp-Actin-Filament-Dependent and -Independent Manners in Arabidopsis thaliana.

    Science.gov (United States)

    Suetsugu, Noriyuki; Higa, Takeshi; Gotoh, Eiji; Wada, Masamitsu

    2016-01-01

    Light-induced chloroplast movement and attachment to the plasma membrane are dependent on actin filaments. In Arabidopsis thaliana, the short actin filaments on the chloroplast envelope, cp-actin filaments, are essential for chloroplast movement and positioning. Furthermore, cp-actin-filament-mediated chloroplast movement is necessary for the strong-light-induced nuclear avoidance response. The proteins CHLOROPLAST UNUSUAL POSITIONING 1 (CHUP1), KINESIN-LIKE PROTEIN FOR ACTIN-BASED CHLOROPLAST MOVEMENT 1 (KAC1) and KAC2 are required for the generation and/or maintenance of cp-actin filaments in Arabidopsis. In land plants, CHUP1 and KAC family proteins play pivotal roles in the proper movement of chloroplasts and their attachment to the plasma membrane. Here, we report similar but distinct phenotypes in chloroplast and nuclear photorelocation movements between chup1 and kac1kac2 mutants. Measurement of chloroplast photorelocation movement indicated that kac1kac2, but not chup1, exhibited a clear strong-light-induced increase in leaf transmittance changes. The chloroplast movement in kac1kac2 depended on phototropin 2, CHUP1 and two other regulators for cp-actin filaments, PLASTID MOVEMENT IMPAIRED 1 and THRUMIN 1. Furthermore, kac1kac2 retained a weak but significant nuclear avoidance response although chup1 displayed a severe defect in the nuclear avoidance response. The kac1kac2chup1 triple mutant was completely defective in both chloroplast and nuclear avoidance responses. These results indicate that CHUP1 and the KACs function somewhat independently, but interdependently mediate both chloroplast and nuclear photorelocation movements.

  17. Effect of the thickness of light absorption layer on the light-induced transverse thermoelectric effect in Bi2Sr2Co2Oy films

    Institute of Scientific and Technical Information of China (English)

    Guoying Yan; Liqing Sun; Shufang Wang; Guangsheng Fu

    2015-01-01

    Light-induced transverse thermoelectric effect is investigated in incline-oriented Bi2 Sr2Co2Oy thin films covered with a graphite light absorption layer.Upon the illumination of a 980 nm cw laser,an enhanced voltage signal is detected and the improvement degree is found to be dependent on the thickness of the graphite layer.A twodimensional (2D) heat transport model using the finite-difference method provides a reasonable explanation to the experimental data.Present results give some valuable instructions for the design of light absorption layers in this type of detector.

  18. Spectral anomalies of the effect of light-induced drift of caesium atoms caused by the velocity dependence of transport collision frequencies

    Energy Technology Data Exchange (ETDEWEB)

    Parkhomenko, A I [Institute of Automation and Electrometry, Siberian Branch of the Russian Academy of Sciences, Novosibirsk (Russian Federation); Shalagin, A M [Novosibirsk State University, Novosibirsk (Russian Federation)

    2014-10-31

    The spectral features of the light-induced drift (LID) velocity of caesium atoms in inert buffer gases are studied theoretically. A strong temperature dependence of the spectral LID line shape of Cs atoms in Ar or Kr atmosphere in the vicinity of T ∼ 1000 K is predicted. It is shown that the anomalous LID of Cs atoms in binary buffer mixtures of two different inert gases can be observed at virtually any (including ambient) temperature, depending on the content of the components in these mixtures. The results obtained make it possible to precisely test the interatomic interaction potentials in the experiments on the anomalous LID. (quantum optics)

  19. Light induced diffusion driven self assembly of Ag nanoparticles in a-Se/Ag bi-layer thin film with ultrafast optical response

    Science.gov (United States)

    Bapna, Mukund; Sharma, Rituraj; Barik, A. R.; Khan, Pritam; Ranjan Kumar, Rakesh; Adarsh, K. V.

    2013-05-01

    In this Letter, we demonstrate that femtosecond light-induced interdiffusion of Ag driven by the electrostatic attraction between photo-excited Ag+ ions and negatively charged amorphous layer can act as an efficient single step method for hybrid integration of spatially ordered and interconnected nanoparticles on the surface of amorphous films. Such self assembled complex hybrid structures of silver nanoparticles via bottom-up nano-construction method on a-Se thin film show an ultrafast optical response over an unusually broad wavelength range that can be used to construct optical modulators operating at switching speed of ˜5 ps.

  20. The impact of gate dielectric materials on the light-induced bias instability in Hf-In-Zn-O thin film transistor

    Science.gov (United States)

    Kwon, Jang-Yeon; Jung, Ji Sim; Son, Kyoung Seok; Lee, Kwang-Hee; Park, Joon Seok; Kim, Tae Sang; Park, Jin-Seong; Choi, Rino; Jeong, Jae Kyeong; Koo, Bonwon; Lee, Sang Yoon

    2010-11-01

    This study examined the effect of gate dielectric materials on the light-induced bias instability of Hf-In-Zn-O (HIZO) transistor. The HfOx and SiNx gated devices suffered from a huge negative threshold voltage (Vth) shift (>11 V) during the application of negative-bias-thermal illumination stress for 3 h. In contrast, the HIZO transistor exhibited much better stability (<2.0 V) in terms of Vth movement under identical stress conditions. Based on the experimental results, we propose a plausible degradation model for the trapping of the photocreated hole carrier either at the channel/gate dielectric or dielectric bulk layer.

  1. A comparison of acetate and digital templating for hip resurfacing.

    Science.gov (United States)

    Bracey, Daniel N; Seyler, Thorsten M; Shields, John S; Leng, Xiaoyan; Jinnah, Riyaz H; Lang, Jason E

    2014-01-01

    This study sought to determine whether templating for metal-on-metal hip resurfacing is more accurate with digital or acetate methodology. The medical records of 102 consecutive patients who underwent hip resurfacing at our institution were retrospectively reviewed. Records lacking preoperative radiographs that included a magnification-establishing marker were excluded, leaving 78 records for study. Two investigators independently prepared acetate and digital templates of the preoperative radiographs, which had been calibrated to 120% magnification, to predict femoral and acetabular component size. Accuracy was measured by comparing the predicted component sizes to the surgically implanted component sizes. Digital templating was more accurate than acetate templating in predicting hip resurfacing component size when measuring accuracy of templates by the absolute error of predicted component sizes (femoral, P hip resurfacing procedures.

  2. Synthesis of 3D ordered porous polystyrene using silica template

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A rigid colloidal silica template was formed by self-assembly ofthe monodispersed silica spheres prepared according to St-ber method. The silica template is highly ordered, which was verified by bright color effect due to Bragg diffraction and the results of SEM. The free radical polymerization of styrene was allowed within the interstices of the rigid template to result in the formation of the three- dimensional periodic silica/polystyrene nano-composites. The titled porous polystyrene was prepared by chemical decom- position of the template with concentrated aqueous hydro- fluoric acid. Scanning electron microscopy characterization showed that the macroporous polystyrene has ordered arrays of the uniform pores replicated from the template. Moreover, it was found that the morphology of the as-synthesized macroporous polystyrene was greatly affected by the connectivity of the silica spheres treated under different conditions.

  3. DNA-templated nickel nanostructures and protein assemblies.

    Science.gov (United States)

    Becerril, Hector A; Ludtke, Paul; Willardson, Barry M; Woolley, Adam T

    2006-11-21

    We report a straightforward method for the fabrication of DNA-templated nickel nanostructures on surfaces. These nickel nanomaterials have potential to be applied as nanowires, as templated catalyst lines, as nanoscale magnetic domains, or in directed protein localization. Indeed, we show here that histidine-tagged phosducin-like protein (His-PhLP) binds with high selectivity to both Ni2+-treated surface DNA and DNA-templated nickel metal to create linear protein assemblies on surfaces. The association of His-PhLP with DNA-templated nickel ions or metal is reversible under appropriate rinsing conditions. Nanoscale DNA-templated protein assemblies might be useful in the construction of high-density protein lines for proteomic analysis, for example. Importantly, these nanofabrication procedures are not limited to linear DNA and can be applied readily to other self-assembled DNA topologies.

  4. Nanostructure templating using low temperature atomic layer deposition

    Science.gov (United States)

    Grubbs, Robert K.; Bogart, Gregory R.; Rogers, John A.

    2011-12-20

    Methods are described for making nanostructures that are mechanically, chemically and thermally stable at desired elevated temperatures, from nanostructure templates having a stability temperature that is less than the desired elevated temperature. The methods comprise depositing by atomic layer deposition (ALD) structural layers that are stable at the desired elevated temperatures, onto a template employing a graded temperature deposition scheme. At least one structural layer is deposited at an initial temperature that is less than or equal to the stability temperature of the template, and subsequent depositions made at incrementally increased deposition temperatures until the desired elevated temperature stability is achieved. Nanostructure templates include three dimensional (3D) polymeric templates having features on the order of 100 nm fabricated by proximity field nanopatterning (PnP) methods.

  5. Assistant template and co-template agents in modeling mesoporous silicas and post-synthesizing organofunctionalizations

    Science.gov (United States)

    Oliveira, Vaeudo V.; Airoldi, Claudio

    2012-12-01

    Mesoporous SBA-16 silicas were synthesized through a direct methodology using the template (F127) combined with co-templates (ethanol and n-butanol), with tetraethylorthosilicate as the silica source. These ordered mesoporous silica were characterized by elemental analyses, infrared spectroscopy, solid-state nuclear magnetic resonance for 13C (CP/MAS) and 29Si (HP/DEC) nuclei, nitrogen sorption/desorption processes, small angle X-ray analyses (SAXS) and transmission electron microscopy (TEM). SAXS and TEM results confirmed the space group Im3m and cubic 3D symmetry, typical for highly ordered SBA-16. The sorption/desorption data for SBA-16 and when functionalized gave type IV isotherms, with hysteresis loop H2. Surface areas of 836; 657 and 618 m2 g-1 and average pore diameters of 7.99; 8.10 and 9.85 nm, for SBA-16A, SBA-16B and SBA-16C were obtained, respectively. When functionalized the silicas presented a reduction in surface area, pore volume and pore diameter due to the pendant chains that interfere with nitrogen sorption in these measurements. The co-template ethanol favors the ordered mesopores with highest wall thicknesses.

  6. Fundamentals of fiber bonding in thermally point-bonded nonwovens

    Science.gov (United States)

    Chidambaram, Aparna

    Thermal point bonding (TPB) uses heat and pressure to bond a web of fibers at discrete points imparting strength to the manufactured fabric. This process significantly reduces the strength and elongation of the bridging fibers between bond points while strengthening the web. Single fiber experiments were performed with four structurally different polypropylene fibers to analyze the inter-relationships between fiber structure, fiber properties and bonding process. Two fiber types had a low birefringence sheath or surface layer while the remaining had uniform birefringence profiles through their thickness. Bonds were formed between isolated pairs of fibers by subjecting the fibers to a calendering process and simulating TPB process conditions. The dependence of bond strength on bonding temperature and on the type of fiber used was evaluated. Fiber strengths before and after bonding were measured and compared to understand the effect of bonding on fiber strength. Additionally, bonded fiber strength was compared to the strength of single fibers which had experienced the same process conditions as the bonded pairs. This comparison estimated the effect of mechanical damage from pressing fibers together with steel rolls while creating bonds in TPB. Interfiber bond strength increased with bonding temperature for all fiber types. Fiber strength decreased with increasing bonding temperature for all fiber types except for one type of low birefringent sheath fibers. Fiber strength degradation was unavoidable at temperatures required for successful bonding. Mechanical damage from compression of fibers between rolls was an insignificant factor in this strength loss. Thermal damage during bonding was the sole significant contributor to fiber strength degradation. Fibers with low birefringence skins formed strong bonds with minimal fiber strength loss and were superior to fibers without such surface layers in TPB performance. A simple model to predict the behavior of a two-bond

  7. Modelling longevity bonds: Analysing the Swiss Re Kortis bond

    OpenAIRE

    2015-01-01

    A key contribution to the development of the traded market for longevity risk was the issuance of the Kortis bond, the world's first longevity trend bond, by Swiss Re in 2010. We analyse the design of the Kortis bond, develop suitable mortality models to analyse its payoff and discuss the key risk factors for the bond. We also investigate how the design of the Kortis bond can be adapted and extended to further develop the market for longevity risk.

  8. Thick orientation-patterned growth of GaP on wafer-fused GaAs templates by hydride vapor phase epitaxy for frequency conversion

    Science.gov (United States)

    Vangala, Shivashankar; Kimani, Martin; Peterson, Rita; Stites, Ron; Snure, Michael; Tassev, Vladimir

    2016-10-01

    Quasi-phase-matched (QPM) GaP layers up to 300 μm thick have been produced by low-pressure hydride vapor phase epitaxy (LP-HVPE) overgrowth on orientation-patterned GaAs (OPGaAs) templates fabricated using a wafer-fusion bonding technique. The growth on the OPGaAs templates resulted in up to 200 μm thick vertically propagating domains, with a total GaP thickness of 300 μm. The successful thick growth on OPGaAs templates is the first step towards solving the material problems associated with unreliable material quality of commercially available GaP wafers and making the whole process of designing QPM frequency conversion devices molecular beam epitaxy free and more cost-effective.

  9. Romanian government bond market

    Directory of Open Access Journals (Sweden)

    Cornelia POP

    2012-12-01

    Full Text Available The present paper aims to present the level of development reached by Romanian government bond market segment, as part of the country financial market. The analysis will be descriptive (the data series available for Romania are short, based on the secondary data offered by the official bodies involved in the process of issuing and trading the Romanian government bonds (Romanian Ministry of Public Finance, Romanian National Bank and Bucharest Stock Exchange, and also on secondary data provided by the Federation of European Stock Exchanges.To enhance the market credibility as a benchmark, a various combination of measures is necessary; among these measures are mentioned: the extension of the yield curve; the issuance calendars in order to improve transparency; increasing the disclosure of information on public debt issuance and statistics; holding regular meetings with dealers, institutional investors and rating agencies; introducing a system of primary dealers; establishing a repurchase (repo market in the government bond market. These measures will be discussed based on the evolution presented inside the paper.The paper conclude with the fact that, until now, the Romanian government bond market did not provide a benchmark for the domestic financial market and that further efforts are needed in order to increase the government bond market transparency and liquidity.

  10. Safe and Liquid Mortgage Bonds

    DEFF Research Database (Denmark)

    Dick-Nielsen, Jens; Gyntelberg, Jacob; Lund, Jesper

    This paper shows that strict match pass-through funding of covered bonds provides safe and liquid mortgage bonds. Despite a 30% drop in house prices during the 2008 global crisis Danish mortgage bonds remained as liquid as most European government bonds. The Danish pass-through system effectively...... eliminates credit risk from the investor's perspective. Similar to other safe bonds, funding liquidity becomes the main driver of mortgage bond liquidity and this creates commonality in liquidity across markets and countries. These findings have implications for how to design a robust mortgage bond system...

  11. Corporate Bonds in Denmark

    DEFF Research Database (Denmark)

    Tell, Michael

    2015-01-01

    Corporate financing is the choice between capital generated by the corporation and capital from external investors. However, since the financial crisis shook the markets in 2007–2008, financing opportunities through the classical means of financing have decreased. As a result, corporations have...... markets. However, NASDAQ OMX has introduced the First North Bond Market in December 2012 and new regulatory framework came into place in 2014, which may contribute to a Danish based corporate bond market. The purpose of this article is to present the regulatory changes in Denmark in relation to corporate...

  12. The Trouble With Bonds

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ In early June,global financial markets gyrated downwards in the wake of central banks'tough language on inflation.At one point bond prices reflected expectations of four rate hikes by the US Federal Reserve (Fed) in the next 12 months.As a result,the dollar firmed,oil prices stabilized,and yield curves flattened around the world.If all these inflation-fighting measures are real,the situation bodes well for bonds.But,I think otherwise.

  13. Cooperativity in beryllium bonds.

    Science.gov (United States)

    Alkorta, Ibon; Elguero, José; Yáñez, Manuel; Mó, Otilia

    2014-03-07

    A theoretical study of the beryllium bonded clusters of the (iminomethyl)beryllium hydride and (iminomethyl)beryllium fluoride [HC(BeX)=NH, X = H, F] molecules has been carried out at the B3LYP/6-311++G(3df,2p) level of theory. Linear and cyclic clusters have been characterized up to the decamer. The geometric, energetic, electronic and NMR properties of the clusters clearly indicate positive cooperativity. The evolution of the molecular properties, as the size of the cluster increases, is similar to those reported in polymers held together by hydrogen bonds.

  14. AgInS{sub 2}-ZnS nanocrystals: Evidence of bistable states using light-induced electron paramagnetic resonance and photoluminescence

    Energy Technology Data Exchange (ETDEWEB)

    Nobre, Sonia S.; Renard, Olivier; Chevallier, Theo; Le Blevennec, Gilles [Laboratoire d' Innovation pour les Technologies des Energies Nouvelles et les Nanomateriaux, Departement de Technologie des Nano-Materiaux, Service d' Elaboration de Nanomateriaux, Laboratoire de Synthese et Integration des Nanomateriaux, CEA-Grenoble (France); Lombard, Christian; Pepin-Donat, Brigitte [Laboratoire Structure et Proprietes d' Architecture Moleculaire (UMR 5819) CEA-CNRS - UJF/INAC/CEA-Grenoble (France)

    2014-04-15

    The precursor (AgIn){sub x} Zn{sub 2(1-x)}(S{sub 2}CN(C{sub 2}H{sub 5}){sub 2}){sub 4} was used to prepared AgInS{sub 2}-ZnS nanocrystals with different compositions (x = 0.4 and x = 0.7) and with different time of reaction (10 min and 75 min). The photoluminescence features of the nanocrystals were addressed by combining steady-state spectroscopy and light-induced electron paramagnetic resonance. Both techniques showed the contribution of at least two components for the emission, previously assigned to surface and intrinsic states. Light-induced electron paramagnetic resonance allowed detection of the photocreation both of irreversible paramagnetic species that are likely responsible for the nano-crystals degradation assigned to surface states and of reversible paramagnetic species assigned to intrinsic states. Moreover, reversible bistable paramagnetic states were observed. This Letter provides a scheme that might be useful in addressing the well-known problem of aging of the nanocrystals. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  15. Design of Poly(L-lactide)-Poly(ethylene glycol) Copolymer with Light-Induced Shape-Memory Effect Triggered by Pendant Anthracene Groups.

    Science.gov (United States)

    Xie, Hui; He, Man-jie; Deng, Xiao-Ying; Du, Lan; Fan, Cheng-Jie; Yang, Ke-Ke; Wang, Yu-Zhong

    2016-04-13

    A novel light-induced shape-memory material based on poly(l-lactide)-poly(ethylene glycol) copolymer is developed successfully by dangling the photoresponsive anthracene group on the PEG soft segment selectively. For synthesis strategy, the preprepared photoresponsive monomer N,N-bis(2-hydroxyethyl)-9-anthracene-methanamine (BHEAA) is first embedded into PEG chains; then, we couple this anthracene-functionalized PEG precursor with PLA precursor to result in PLA-PEG-A copolymer. The composition of target product can be well-defined by simply adjusting the feed ratio. The chemical structures of intermediate and final products are confirmed by (1)H NMR. Differential scanning calorimetry analysis of material reveals that the PEG soft segment became noncrystallizable when 4% or more BHEAA is introduced, and this feature is beneficial to the mobility of anthracene groups in polymer matrix. The static tensile tests show that the samples exhibit rubberlike mechanical properties except for the PLA-dominant one. The reversibility of [4 + 4] cycloaddition reaction between pendant anthracene groups in PLA-PEG-A film is demonstrated by UV-vis. Eventually, the light-induced shape-memory effect (LSME) is successfully realized in PLA-PEG-A. The results of cyclic photomechanical tests also reveal that the content of PLA hard segment as well as photosensitive anthracene moieties plays a crucial role in LSME.

  16. Loss of Melanopsin Photoreception and Antagonism of the Histamine H3 Receptor by Ciproxifan Inhibit Light-Induced Sleep in Mice.

    Science.gov (United States)

    Muindi, Fanuel; Colas, Damien; Ikeme, Jesse; Ruby, Norman F; Heller, H Craig

    2015-01-01

    Light has direct effects on sleep and wakefulness causing arousal in diurnal animals and sleep in nocturnal animals. In the present study, we assessed the modulation of light-induced sleep by melanopsin and the histaminergic system by exposing mice to millisecond light flashes and continuous light respectively. First, we show that the induction of sleep by millisecond light flashes is dose dependent as a function of light flash number. We found that exposure to 60 flashes of light occurring once every 60 seconds for 1-h (120-ms of total light over an hour) induced a similar amount of sleep as a continuous bright light pulse. Secondly, the induction of sleep by millisecond light flashes was attenuated in the absence of melanopsin when animals were presented with flashes occurring every 60 seconds over a 3-h period beginning at ZT13. Lastly, the acute administration of a histamine H3 autoreceptor antagonist, ciproxifan, blocked the induction of sleep by a 1-h continuous light pulse during the dark period. Ciproxifan caused a decrease in NREMS delta power and an increase in theta activity during both sleep and wake periods respectively. The data suggest that some form of temporal integration occurs in response to millisecond light flashes, and that this process requires melanopsin photoreception. Furthermore, the pharmacological data suggest that the increase of histaminergic neurotransmission is sufficient to attenuate the light-induced sleep response during the dark period.

  17. Hierarchical nanostructures assembled from ultrathin Bi{sub 2}WO{sub 6} nanoflakes and their visible-light induced photocatalytic property

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xiong, E-mail: xiongwang@njust.edu.cn [School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094 (China); Department of Chemistry, Faculty of Science, National University of Singapore, 3 Science Drive 3, 117543 (Singapore); Tian, Peng; Lin, Ying; Li, Li [School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094 (China)

    2015-01-25

    Graphical abstract: Hierarchical Bi{sub 2}WO{sub 6} nanostructures assembled from nanoflakes were successfully synthesized by a facile hydrothermal method. The excellent photocatalytic activity and recycling performance might be mainly ascribed to the unique hierarchical nanostructures and are expected to offer the nanostructures promising applications in the field of wastewater treatment. - Highlights: • Hierarchical Bi{sub 2}WO{sub 6} nanostructures assembled from nanoflakes were successfully synthesized by a facile hydrothermal method. • Visible-light-induced photocatalytic efficiency of the obtained nanoarchitectures was enhanced about 6 times. • A possible mechanism was proposed. - Abstract: With the aid of ethylene glycol and sodium dodecylbenzene sulfonate, the hierarchical Bi{sub 2}WO{sub 6} nanoarchitectures assembled from nanoflakes could be attained by a facile solvothermal method. The synthetic strategy is versatile and environmentally friendly and a plausible growth-assembly process was proposed for the formation of the hierarchical nanostructures. The visible-light-irradiated photocatalytic activity was estimated by the degradation of rhodamine B. Compared with the sample prepared by a solid-state reaction, the visible-light-induced photocatalytic efficiency of the nanostructures was enhanced about 6 times. The photocatalysis tests show that the nanostructures exhibit excellent photocatalytic activity and recycling performance, which were mainly ascribed to the unique hierarchical nanostructures and are expected to offer promising applications in the field of wastewater treatment.

  18. Effect of Furan Fatty Acids and 3-Methyl-2,4-nonanedione on Light-Induced Off-Odor in Soybean Oil.

    Science.gov (United States)

    Sano, Takashi; Okabe, Ryo; Iwahashi, Maiko; Imagi, Jun; Sato, Toshiro; Yamashita, Toshiyuki; Fukusaki, Eiichiro; Bamba, Takeshi

    2017-02-28

    Soybean oil is one of the most widely consumed vegetable oils. However, under photooxidative conditions, this oil develops a beany and green off-odor through a mechanism that has not yet been elucidated. Upon photooxidation, 3-methyl-2,4-nonanedione (3-MND) produces a strong aroma. In this study, the effect of furan fatty acids and 3-MND on odor reversion in soybean oil was investigated. Our findings suggest that the observed light-induced off-odor was likely attributable to the furan fatty acids present in the oil through the generation of 3-MND. While 3-MND may not be directly responsible for the development of light-induced off-odor, this compound appears to be involved because off-odor was detected in canola oil samples containing added 3-MND. In addition, in the present work, 3-hydroxy-3-methyl-2,4-nonanedione, which is derived from 3-MND, was identified for the first time in light-exposed soybean oil and shown to be one of the compounds responsible for odor reversion.

  19. Loss of Melanopsin Photoreception and Antagonism of the Histamine H3 Receptor by Ciproxifan Inhibit Light-Induced Sleep in Mice.

    Directory of Open Access Journals (Sweden)

    Fanuel Muindi

    Full Text Available Light has direct effects on sleep and wakefulness causing arousal in diurnal animals and sleep in nocturnal animals. In the present study, we assessed the modulation of light-induced sleep by melanopsin and the histaminergic system by exposing mice to millisecond light flashes and continuous light respectively. First, we show that the induction of sleep by millisecond light flashes is dose dependent as a function of light flash number. We found that exposure to 60 flashes of light occurring once every 60 seconds for 1-h (120-ms of total light over an hour induced a similar amount of sleep as a continuous bright light pulse. Secondly, the induction of sleep by millisecond light flashes was attenuated in the absence of melanopsin when animals were presented with flashes occurring every 60 seconds over a 3-h period beginning at ZT13. Lastly, the acute administration of a histamine H3 autoreceptor antagonist, ciproxifan, blocked the induction of sleep by a 1-h continuous light pulse during the dark period. Ciproxifan caused a decrease in NREMS delta power and an increase in theta activity during both sleep and wake periods respectively. The data suggest that some form of temporal integration occurs in response to millisecond light flashes, and that this process requires melanopsin photoreception. Furthermore, the pharmacological data suggest that the increase of histaminergic neurotransmission is sufficient to attenuate the light-induced sleep response during the dark period.

  20. Investigation of the a-Si:H films by using thermal and light-induced annealing treatment in atomic hydrogen atmosphere in H-W-ECR CVD system

    Institute of Scientific and Technical Information of China (English)

    Hu Yue-Hui; Deng Jin-Xiang; Zhu Xiu-Hong; Chen Guang-Hua; Rong Yan-Dong; Li Ying; Song Xue-Mei; Zhou Huai-En; Gao Zhuo; Ma Zhan-Jie

    2005-01-01

    To Investigate the stability of hydrogenated amorphous silicon (a-Si:H) films, the thermal and light-induced annealing treatment in an atomic hydrogen atmosphere (TLAH) is carried out by using a new hot-wire-assisted microwave electron-cyclotron-resonance chemical vapour deposition system (H-W-ECR CVD) modified from a conventional microwave electronic cyclotron resonance chemical vapor deposition system (MWECR CVD). In order to compare with the TLAH method, the experiments of thermal annealing, and thermal and light-induced annealing are also performed.Meanwhile, for the purpose of analysing the photoconductivity degradation quantitative, the photoconductivity degradation is assumed to obey the extended exponential law: 1/σph=1/σs-(1/σs-1/σ0)exp[-(t/τ)β], where the extended exponentialβ and the time constant τ are gained by the slope and the intercept of the line according to the linear relationship between In (-ln(σs-1-σ-1ph/σs-1-σ-10)) and Int, deduced from the extended exponential law; the photoconductivity saturation value σs can be obtained by Gaussian fitting according to the relationship between photoconductivity and light-soaking time in the logarithmic coordinate system. The experimental results show that the TLAH can improve the stability, microstructure and opto-electronic properties of the annealed a-Si:H films, obviously decrease their optical band gaps, and remarkably move their photoluminescence spectrum (PL) peaks toward low energies.

  1. Role of AtPolζ, AtRev1, and AtPolη in UV light-induced mutagenesis in Arabidopsis.

    Science.gov (United States)

    Nakagawa, Mayu; Takahashi, Shinya; Tanaka, Atsushi; Narumi, Issay; Sakamoto, Ayako N

    2011-01-01

    Translesion synthesis (TLS) is a DNA damage tolerance mechanism in which DNA lesions are bypassed by specific polymerases. To investigate the role of TLS activities in ultraviolet light-induced somatic mutations, we analyzed Arabidopsis (Arabidopsis thaliana) disruptants of AtREV3, AtREV1, and/or AtPOLH genes that encode TLS-type polymerases. The mutation frequency in rev3-1 or rev1-1 mutants decreased compared with that in the wild type, suggesting that AtPolζ and AtRev1 perform mutagenic bypass events, whereas the mutation frequency in the polh-1 mutant increased, suggesting that AtPolη performs nonmutagenic bypass events with respect to ultraviolet light-induced lesions. The rev3-1 rev1-1 double mutant showed almost the same mutation frequency as the rev1-1 single mutant. The increased mutation frequency found in polh-1 was completely suppressed in the rev3-1 polh-1 double mutant, indicating that AtPolζ is responsible for the increased mutations found in polh-1. In summary, these results suggest that AtPolζ and AtRev1 are involved in the same (error-prone) TLS pathway that is independent from the other (error-free) TLS pathway mediated by AtPolη.

  2. Loss of Melanopsin Photoreception and Antagonism of the Histamine H3 Receptor by Ciproxifan Inhibit Light-Induced Sleep in Mice

    Science.gov (United States)

    Muindi, Fanuel; Colas, Damien; Ikeme, Jesse; Ruby, Norman F.; Heller, H. Craig

    2015-01-01

    Light has direct effects on sleep and wakefulness causing arousal in diurnal animals and sleep in nocturnal animals. In the present study, we assessed the modulation of light-induced sleep by melanopsin and the histaminergic system by exposing mice to millisecond light flashes and continuous light respectively. First, we show that the induction of sleep by millisecond light flashes is dose dependent as a function of light flash number. We found that exposure to 60 flashes of light occurring once every 60 seconds for 1-h (120-ms of total light over an hour) induced a similar amount of sleep as a continuous bright light pulse. Secondly, the induction of sleep by millisecond light flashes was attenuated in the absence of melanopsin when animals were presented with flashes occurring every 60 seconds over a 3-h period beginning at ZT13. Lastly, the acute administration of a histamine H3 autoreceptor antagonist, ciproxifan, blocked the induction of sleep by a 1-h continuous light pulse during the dark period. Ciproxifan caused a decrease in NREMS delta power and an increase in theta activity during both sleep and wake periods respectively. The data suggest that some form of temporal integration occurs in response to millisecond light flashes, and that this process requires melanopsin photoreception. Furthermore, the pharmacological data suggest that the increase of histaminergic neurotransmission is sufficient to attenuate the light-induced sleep response during the dark period. PMID:26083020

  3. Tobacco guard cells fix CO2 by both Rubisco and PEPcase while sucrose acts as a substrate during light-induced stomatal opening.

    Science.gov (United States)

    Daloso, Danilo M; Antunes, Werner C; Pinheiro, Daniela P; Waquim, Jardel P; Araújo, Wagner L; Loureiro, Marcelo E; Fernie, Alisdair R; Williams, Thomas C R

    2015-11-01

    Transcriptomic and proteomic studies have improved our knowledge of guard cell function; however, metabolic changes in guard cells remain relatively poorly understood. Here we analysed metabolic changes in guard cell-enriched epidermal fragments from tobacco during light-induced stomatal opening. Increases in sucrose, glucose and fructose were observed during light-induced stomatal opening in the presence of sucrose in the medium while no changes in starch were observed, suggesting that the elevated fructose and glucose levels were a consequence of sucrose rather than starch breakdown. Conversely, reduction in sucrose was observed during light- plus potassium-induced stomatal opening. Concomitant with the decrease in sucrose, we observed an increase in the level as well as in the (13) C enrichment in metabolites of, or associated with, the tricarboxylic acid cycle following incubation of the guard cell-enriched preparations in (13) C-labelled bicarbonate. Collectively, the results obtained support the hypothesis that sucrose is catabolized within guard cells in order to provide carbon skeletons for organic acid production. Furthermore, they provide a qualitative demonstration that CO2 fixation occurs both via ribulose-1,5-biphosphate carboxylase/oxygenase (Rubisco) and phosphoenolpyruvate carboxylase (PEPcase). The combined data are discussed with respect to current models of guard cell metabolism and function.

  4. Light induced EPR spectra of reaction centers from Rhodobacter sphaeroides at 80K: Evidence for reduction of QB by B-branch electron transfer in native reaction centers.

    Science.gov (United States)

    Paddock, M. L; Isaacson, R. A.; Abresch, E. C.; Okamura, M. Y.

    2006-01-01

    Photosynthetic reaction centers (RCs) from Rhodobacter sphaeroides capture solar energy by electron transfer from primary donor, D, to quinone acceptor, QB, through the active A-branch of electron acceptors, but not the inactive B-branch. The light induced EPR spectrum from native RCs that had Fe2+ replaced by Zn2+ was investigated at cryogenic temperature (80K, 35 GHz). In addition to the light induced signal due to formation of D+•QA−• observed previously, a small fraction (~5%) of the signal displayed very different characteristics: (1) The signal was absent in RCs in which the QB was displaced by the inhibitor stigmatellin. (2) Its decay time (τ=6 s) was the same as observed for D+•QB−• in mutant RCs lacking QA, which is significantly slower than for D+•QA−• (τ=30 ms). (3) Its EPR spectrum was identical to that of D+•QB−•. (4) The quantum efficiency for forming the major component of the signal was the same as that found for mutant RCs lacking QA (Φ =0.2%) and was temperature independent. These results are explained by direct photochemical reduction of QB via B-branch electron transfer in a small fraction of native RCs. PMID:18163156

  5. Root cap-dependent gravitropic U-turn of maize root requires light-induced auxin biosynthesis via the YUC pathway in the root apex

    Science.gov (United States)

    Suzuki, Hiromi; Yokawa, Ken; Nakano, Sayuri; Yoshida, Yuriko; Fabrissin, Isabelle; Okamoto, Takashi; Baluška, František; Koshiba, Tomokazu

    2016-01-01

    Gravitropism refers to the growth or movement of plants that is influenced by gravity. Roots exhibit positive gravitropism, and the root cap is thought to be the gravity-sensing site. In some plants, the root cap requires light irradiation for positive gravitropic responses. However, the mechanisms regulating this phenomenon are unknown. We herein report that maize roots exposed to white light continuously for ≥1–2h show increased indole-3-acetic acid (IAA) levels in the root tips, especially in the transition zone (1–3mm from the tip). Treatment with IAA biosynthesis inhibitors yucasin and l-kynurenine prevented any increases in IAA content and root curvature under light conditions. Analyses of the incorporation of a stable isotope label from tryptophan into IAA revealed that some of the IAA in roots was synthesized in the root apex. Furthermore, Zmvt2 and Zmyuc gene transcripts were detected in the root apex. One of the Zmyuc genes (ZM2G141383) was up-regulated by light irradiation in the 0–1mm tip region. Our findings suggest that IAA accumulation in the transition zone is due to light-induced activation of Zmyuc gene expression in the 0–1mm root apex region. Light-induced changes in IAA levels and distributions mediate the maize root gravitropic U-turn. PMID:27307546

  6. Semiconductor nanowires and templates for electronic applications

    Energy Technology Data Exchange (ETDEWEB)

    Ying, Xiang

    2009-07-15

    This thesis starts by developing a platform for the organized growth of nanowires directly on a planar substrate. For this, a method to fabricate horizontal porous alumina membranes is studied. The second part of the thesis focuses on the study of nanowires. It starts by the understanding of the growth mechanisms of germanium nanowires and follows by the structural and electrical properties at the single nanowire level. Horizontally aligned porous anodic alumina (PAA) was used as a template for the nanowire synthesis. Three PAA arrangements were studied: - high density membranes - micron-sized fingers - multi-contacts Membranes formed by a high density of nanopores were obtained by anodizing aluminum thin films. Metallic and semiconducting nanowires were synthesized into the PAA structures via DC deposition, pulsed electro-depostion and CVD growth. The presence of gold, copper, indium, nickel, tellurium, and silicon nanowires inside PAA templates was verified by SEM and EDX analysis. Further, room-temperature transport measurements showed that the pores are completely filled till the bottom of the pores. In this dissertation, single crystalline and core-shell germanium nanowires are synthesized using indium and bismuth as catalyst in a chemical vapor deposition procedure with germane (GeH{sub 4}) as growth precursor. A systematic growth study has been performed to obtain high aspect-ratio germanium nanowires. The influence of the growth conditions on the final morphology and the crystalline structure has been determined via scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). In the case of indium catalyzed germanium nanowires, two different structures were identified: single crystalline and crystalline core-amorphous shell. The preferential growth axis of both kinds of nanowires is along the [110] direction. The occurrence of the two morphologies was found to only depend on the nanowire dimension. In the case of bismuth

  7. Hydrogen bond and halogen bond inside the carbon nanotube

    Science.gov (United States)

    Wang, Weizhou; Wang, Donglai; Zhang, Yu; Ji, Baoming; Tian, Anmin

    2011-02-01

    The hydrogen bond and halogen bond inside the open-ended single-walled carbon nanotubes have been investigated theoretically employing the newly developed density functional M06 with the suitable basis set and the natural bond orbital analysis. Comparing with the hydrogen or halogen bond in the gas phase, we find that the strength of the hydrogen or halogen bond inside the carbon nanotube will become weaker if there is a larger intramolecular electron-density transfer from the electron-rich region of the hydrogen or halogen atom donor to the antibonding orbital of the X-H or X-Hal bond involved in the formation of the hydrogen or halogen bond and will become stronger if there is a larger intermolecular electron-density transfer from the electron-rich region of the hydrogen or halogen atom acceptor to the antibonding orbital of the X-H or X-Hal bond. According to the analysis of the molecular electrostatic potential of the carbon nanotube, the driving force for the electron-density transfer is found to be the negative electric field formed in the carbon nanotube inner phase. Our results also show that the X-H bond involved in the formation of the hydrogen bond and the X-Hal bond involved in the formation of the halogen bond are all elongated when encapsulating the hydrogen bond and halogen bond within the carbon nanotube, so the carbon nanotube confinement may change the blue-shifting hydrogen bond and the blue-shifting halogen bond into the red-shifting hydrogen bond and the red-shifting halogen bond. The possibility to replace the all electron nanotube-confined calculation by the simple polarizable continuum model is also evaluated.

  8. Synthesis of oligoguanylates on oligocytidylate templates. [on primitive earth

    Science.gov (United States)

    Fakhrai, H.; Van Roode, J. H. G.; Orgel, L. E.

    1981-01-01

    The influence of template length in the self-condensation of guanosine 5'-phosphorimidazole in the presence of oligocytidylate templates is investigated. Reactions were carried out with cyclic cytidine 2',3'-phosphate, oligo- or polyC, and radioactively labeled guanosine 5'-phosphorimidazolide in the presence of Zn(+2) or Pb(+2) catalyst; product yields were determined by paper chromatography, thin-layer chromatography, and high-performance liquid chromatography. In the absence of a catalytic metal or in the presence of Pb(+2), a significant template effect is observed starting with the cytidine dimer and increasing in yield up to the hexamer template. Oligomers longer than the template are observed, and are predominantly 2'-5' linked in the presence of Pb(+2) and of mixed linkages in the uncatalyzed reaction. With the zinc ion as the catalyst, the template effect is first observed with the pentamer and is maximal with the heptamer. Products are predominantly 3'-5', and only a small proportion of them are longer than the template. The importance of the demonstrated formation of molecules with up to 10 guanosine units from oligocytidines as short as the dimer on the primitive earth is noted.

  9. MOCVD epitaxy of InAlN on different templates

    Institute of Scientific and Technical Information of China (English)

    Yun Lijun; Wei Tongbo; Yan Jianchang; Liu Zhe; Wang Junxi; Li Jinmin

    2011-01-01

    InAlN epilayers were grown on high quality GaN and AlN templates with the same growth parameters.Measurement results showed that two samples had the same In content of ~ 16%,while the crystal quality and surface topography of the InA1N epilayer grown on the AlN template,with 282.3" (002) full width at half maximum (FWHM) of rocking curve,313.5" (102) FWHM,surface roughness of 0.39 nm and V-pit density of 2.8 ×108 cm-2,were better than that of the InAlN epilayer grown on the GaN template,309.3",339.1",0.593 nm and 4.2 × 108 cm-2.A primary conclusion was proposed that both the crystal quality and the surface topography of the InAlN epilayer grown on the AlN template were better than that of the InAlN epilayer grown on the GaN template.Therefore,the AlN template was a better choice than the GaN template for getting high quality InA1N epilayers.

  10. Multimodal biometric approach for cancelable face template generation

    Science.gov (United States)

    Paul, Padma Polash; Gavrilova, Marina

    2012-06-01

    Due to the rapid growth of biometric technology, template protection becomes crucial to secure integrity of the biometric security system and prevent unauthorized access. Cancelable biometrics is emerging as one of the best solutions to secure the biometric identification and verification system. We present a novel technique for robust cancelable template generation algorithm that takes advantage of the multimodal biometric using feature level fusion. Feature level fusion of different facial features is applied to generate the cancelable template. A proposed algorithm based on the multi-fold random projection and fuzzy communication scheme is used for this purpose. In cancelable template generation, one of the main difficulties is keeping interclass variance of the feature. We have found that interclass variations of the features that are lost during multi fold random projection can be recovered using fusion of different feature subsets and projecting in a new feature domain. Applying the multimodal technique in feature level, we enhance the interclass variability hence improving the performance of the system. We have tested the system for classifier fusion for different feature subset and different cancelable template fusion. Experiments have shown that cancelable template improves the performance of the biometric system compared with the original template.

  11. Hand Vein Recognition Based on Improved Template Matching

    Directory of Open Access Journals (Sweden)

    Jun Wang

    2014-12-01

    Full Text Available An improved template-construction method for hand vein recognition is presented. The accomplishment of the new algorithm involves several steps. First, we design the power-controlled multispectral vein acquisition handset to establish high-quality hand vein database. Second, we propose an improved valley-shaped enhancement operator with NiBlack algorithm to realize vein segmentation. Third, we get a basic-shaped template after dilation and erosion operation in the four neighborhoods firstly, and then we can get the final matching template combining all the shapes after the process of filling the connected region whose threshold is smaller than the one we set according to the experiment effect. Finally we design the hand vein recognition experiments using the designed template and traditional template respectively. The recognition rate of the improved template is 96.6% under the 1:1 mode and 95.75% under the 1:N mode while the recognition rate of the traditional template is 89.2 under the 1:1 mode and 88.2 under the 1:N mode.

  12. Linear pi-Acceptor-Templated Dynamic Clipping to Macrobicycles and[2]Rotaxanes

    Energy Technology Data Exchange (ETDEWEB)

    Klivansky, Liana M.; Koshkakaryan, Gayane; Cao, Dennis; Liu, Yi

    2009-04-30

    Functional rotaxanes are one of the representative nanoscale molecular machines that have found applications in many areas, including molecular electronics, nanoelectromechanical systems (NEMS), photo controllable smart surfaces, and nanovalves. With the advent of molecular recognition and self-assembly, such molecular compounds can now be obtained efficiently through template-directed synthesis. One of the common strategies of making [2]rotaxanes involves the clipping of a macrocycle around a preformed dumbbell-shaped template in a [1+1] or [2+2] manner. While early examples were based on irreversible kinetic pathway through covalent bond formation, recent advances on reversible dynamic covalent chemistry (DCC) has attracted great attention to this field. By virtue of thermodynamically controlled equilibria, DCC has provided highly efficient and versatile synthetic routes in the selection of specific products from a complex system. Among the several reversible reactions in the category of DCC reactions, the imine formation has proven to be very versatile in macrocyclization to give complex interlocked molecular compounds. Cryptands are three dimensional bicyclic hosts with preorganized cavities capable of inclusion of ions and small molecules. Replacing the nitrogen bridgeheads in common cryptands with aromatic ring systems gives cyclophane-based macrobicycles. The introduction of aromatic ring systems into a preorganized cage-like geometry facilitates ion-{pi} interactions and {pi}-{pi} interactions, resulting in novel metal sandwiches, fluoride receptors, and host-guest complexes. In particular, the seminal work by Gibson, Huang and coworkers on cryptand complexation with paraquat and diquat guests have resulted in the efficient synthesis of mechanically interlocked rotaxanes. The synthesis of cyclophane-based macrobicycles, however, was mostly realized through multiple reaction steps and in high-dilution conditions, which often suffered from low yield and

  13. A biomolecule-compatible visible-light-induced azide reduction from a DNA-encoded reaction-discovery system.

    Science.gov (United States)

    Chen, Yiyun; Kamlet, Adam S; Steinman, Jonathan B; Liu, David R

    2011-02-01

    Using a system that accelerates the serendipitous discovery of new reactions by evaluating hundreds of DNA-encoded substrate combinations in a single experiment, we explored a broad range of reaction conditions for new bond-forming reactions. We discovered reactivity that led to a biomolecule-compatible, Ru(II)-catalysed azide-reduction reaction induced by visible light. In contrast to current azide-reduction methods, this reaction is highly chemoselective and is compatible with alcohols, phenols, acids, alkenes, alkynes, aldehydes, alkyl halides, alkyl mesylates and disulfides. The remarkable functional group compatibility and mild conditions of the reaction enabled the azide reduction of nucleic acid and oligosaccharide substrates, with no detectable occurrence of side reactions. The reaction was also performed in the presence of a protein enzyme without the loss of enzymatic activity, in contrast to two commonly used azide-reduction methods. The visible-light dependence of this reaction provides a means of photouncaging functional groups, such as amines and carboxylates, on biological macromolecules without using ultraviolet irradiation.

  14. Robust structural identification via polyhedral template matching

    Science.gov (United States)

    Mahler Larsen, Peter; Schmidt, Søren; Schiøtz, Jakob

    2016-06-01

    Successful scientific applications of large-scale molecular dynamics often rely on automated methods for identifying the local crystalline structure of condensed phases. Many existing methods for structural identification, such as common neighbour analysis, rely on interatomic distances (or thresholds thereof) to classify atomic structure. As a consequence they are sensitive to strain and thermal displacements, and preprocessing such as quenching or temporal averaging of the atomic positions is necessary to provide reliable identifications. We propose a new method, polyhedral template matching (PTM), which classifies structures according to the topology of the local atomic environment, without any ambiguity in the classification, and with greater reliability than e.g. common neighbour analysis in the presence of thermal fluctuations. We demonstrate that the method can reliably be used to identify structures even in simulations near the melting point, and that it can identify the most common ordered alloy structures as well. In addition, the method makes it easy to identify the local lattice orientation in polycrystalline samples, and to calculate the local strain tensor. An implementation is made available under a Free and Open Source Software license.

  15. Photochemical tissue bonding

    Science.gov (United States)

    Redmond, Robert W.; Kochevar, Irene E.

    2012-01-10

    Photochemical tissue bonding methods include the application of a photosensitizer to a tissue and/or tissue graft, followed by irradiation with electromagnetic energy to produce a tissue seal. The methods are useful for tissue adhesion, such as in wound closure, tissue grafting, skin grafting, musculoskeletal tissue repair, ligament or tendon repair and corneal repair.

  16. Bonding in cementitious composites

    Energy Technology Data Exchange (ETDEWEB)

    Mindess, S. (British Columbia Univ., Vancouver, BC (Canada)) Shah, S.P. (Northwestern Univ., Evanston, IL (USA))

    1988-01-01

    These proceedings discuss the papers presented at the symposium on the subject of high performance cement composites. Some of the topics discussed were; calcium hydroxides treated ceramics microspheres and mechanical properties of high temperature light weight cements; microstructure and chemical variations of class F fly ash; microstructure and bond strength of cement and crack propagation as detected by laser holography and acoustic emission.

  17. Thermal Bond System.

    Science.gov (United States)

    1995-10-31

    a twill weave, a crowfoot weave, a satin weave (FIG. 2), and a leno weave. Descriptions of the various weave types can be found in " Composite ...together to define a fabric mesh having first and second opposing woven surfaces. An adhesive bond that is flowable prior to drying is used to wet and

  18. POROUS MEMBRANE TEMPLATED SYNTHESIS OF POLYMER PILLARED LAYER

    Institute of Scientific and Technical Information of China (English)

    Zhong-wei Niu; Dan Li; Zhen-zhong Yang

    2003-01-01

    The anodic porous alumina membranes with a definite pore diameter and aspect ratio were used as templates to synthesize polymer pillared layer structures. The pillared polymer was produced in the template membrane pores, and the layer on the template surfaces. Rigid cured epoxy resin, polystyrene and soft hydrogel were chosen to confirm the methodology. The pillars were in the form of either tubes or fibers, which were controlled by the alumina membrane pore surface wettability. The structural features were confirmed by scanning electron microscopy results.

  19. Composition Templates in English Writing of the College Entrance Examination

    Institute of Scientific and Technical Information of China (English)

    史秀娟

    2014-01-01

    In recent years, more and more students relay on universal composition templates. Students believe that the"universal composition template" can cope with all kinds of English tests. How the pros and cons of writing methods seem to put things right once and for all? How’s enlightening significance to English teaching? In this paper, based on the two language acquisition theory and analyze the advantages and disadvantages of the composition template, some suggestion are given to the students to im-prove their English writing level.

  20. The biogeochemical cycle of the adsorbed template. I - formation of the template

    Science.gov (United States)

    Lazard, Daniel; Lahav, Noam; Orenberg, J. B.

    1987-01-01

    Experimental results are presented for the verification of the first adsorption step of the 'adsorbed template' biogeochemical cycle, a simple model for a primitive prebiotic replication system. The adsorption of Poly-C, Poly-U, Poly-A, Poly-G, and 5'-AMP, 5'-GMP, 5'-CMP and 5'-UMP onto gypsum was studied. It was found that under the conditions of the experiment, the polymers have a very high affinity for the mineral surface, while the monomers adsorb much less efficiently.

  1. Synthesis of Y2O3: Eu3+ Hollow Spheres Using Silica as Templates

    Institute of Scientific and Technical Information of China (English)

    Liu Guixia; Hong Guangyan; Dong Xiangting; Wang Jinxian

    2007-01-01

    The Y2O3:Eu3+ hollow spheres were synthesized using the template-mediated method. XRD patterns indicated that the broadened diffraction peaks resulted from nanocrystals in Y2O3:Eu3+ shells of hollow spheres. XPS spectra showed that the Y2O3:Eu3+ shells were linked with silica cores by a Si-O-Y chemical bond. SEM and TEM observations showed that the size of the SiO2/Y2O3:Eu3+ core-shell particle was about 100 nm, and the thickness of the Y2O3:Eu3+ hollow sphere was less than 5 nm. The photoluminescence spectra of the SiO2/Y2O3:Eu3+ core-shell materials and Y2O3:Eu3+ hollow spheres had red luminescent properties, and the broadened emission peaks came from nanocrystals composed of the Y2O3:Eu3+ shell.

  2. Supracolloidal Assemblies as Sacrificial Templates for Porous Silk-Based Biomaterials

    Directory of Open Access Journals (Sweden)

    John G. Hardy

    2015-08-01

    Full Text Available Tissues in the body are hierarchically structured composite materials with tissue-specific properties. Urea self-assembles via hydrogen bonding interactions into crystalline supracolloidal assemblies that can be used to impart macroscopic pores to polymer-based tissue scaffolds. In this communication, we explain the solvent interactions governing the solubility of urea and thereby the scope of compatible polymers. We also highlight the role of solvent interactions on the morphology of the resulting supracolloidal crystals. We elucidate the role of polymer-urea interactions on the morphology of the pores in the resulting biomaterials. Finally, we demonstrate that it is possible to use our urea templating methodology to prepare Bombyx mori silk protein-based biomaterials with pores that human dermal fibroblasts respond to by aligning with the long axis of the pores. This methodology has potential for application in a variety of different tissue engineering niches in which cell alignment is observed, including skin, bone, muscle and nerve.

  3. Structure investigation of fluorinated aluminophosphate ULM-3 Al templated by 3-methylaminopropylamine

    Science.gov (United States)

    Zabukovec Logar, Natasa; Mali, Gregor; Rajic, Nevenka; Jevtic, Sanja; Rangus, Mojca; Golobic, Amalija; Kaucic, Venceslav

    2010-05-01

    A single-crystal X-ray diffraction analysis of an open-framework aluminophosphate ULM-3 Al prepared by 3-methylaminopropylamine (MAPA) as structure-directing agent revealed an orthorhombic Pcab symmetry ( a=9.9949(4) Å, b=15.8229(7) Å, c=18.1963(5) Å, R=0.0648, Z=8, unit cell formula [Al 24P 24O 96F 16·C 32H 112N 16]), which differs from the Pbc2 1 symmetry of the structural analogue prepared in the presence of 1,4-diaminobutane. The 27Al, 31P, 19F, 13C and 1H NMR investigations, which were performed to study in detail MAPA arrangement inside the framework as well as the interactions of MAPA with the aluminophosphate host, confirmed the crystal symmetry and the proposed hydrogen bonding scheme between the template and the framework.

  4. MFI-type boroaluminosilicate: A comparative study between the direct synthesis and the templating method

    Science.gov (United States)

    Zhou, Wei; Zhang, Shi-Yu; Hao, Xiang-Ying; Guo, Hao; Zhang, Cui; Zhang, Yin-Qing; Liu, Shuangxi

    2006-03-01

    Boroaluminosilicate with MFI zeotype (henceforth B-ZSM-5) was synthesized both via the direct synthesis where ZSM-5 was employed as crystal seed and the templating method by using TPABr as the structure-directing agent (SDA). Characterization based on its structure, bonding, surface acidity, and morphology was performed by powder X-ray diffraction (XRD), 11B MAS NMR spectrometry, FT-IR spectrometry, pyridine-chemisorption IR spectrometry, and scanning electron microscopy (SEM). The composition of the prepared zeolites was determined by ICP-AES; the zeolite framework stability was investigated by steam treatment. The differences in the physicochemical properties of B-ZSM-5 prepared by the two methods were compared and discussed. In the direct synthesis, increasing initial boron-substitution ratio concomitantly brings about increasing difficulty to prepare pure B-ZSM-5 and, MFI-type borosilicate (free of aluminum) cannot be synthesized; the highest SiO 2/Al 2O 3 ratio=70.64 is received. B-ZSM-5 prepared by the templating method shows remarkable hydrothermal stability than its counterpart prepared by the direct synthesis.

  5. Trading in Treasury Bond Futures Contracts and Bonds in Australia

    OpenAIRE

    Belinda Cheung

    2014-01-01

    Treasury bond futures are a key financial product in Australia, with turnover in Treasury bond futures contracts significantly larger than turnover in the market for Commonwealth Government securities (CGS). Treasury bond futures contracts provide a wide variety of market participants with the ability to hedge against, or gain exposure to, interest rate risk. This article discusses some of the features of the Treasury bond futures contract, and how the contract is used to facilitate hedging a...

  6. Particulate templates and ordered liquid bridge networks in evaporative lithography.

    Science.gov (United States)

    Vakarelski, Ivan U; Kwek, Jin W; Tang, Xiaosong; O'Shea, Sean J; Chan, Derek Y C

    2009-12-01

    We investigate the properties of latex particle templates required to optimize the development of ordered liquid bridge networks in evaporative lithography. These networks are key precursors in the assembly of solutions of conducting nanoparticles into large, optically transparent, and conducting microwire networks on substrates (Vakarelski, I. U.; Chan, D. Y. C.; Nonoguchi, T.; Shinto, H.; Higashitani, K. Phys. Rev. Lett., 2009, 102, 058303). An appropriate combination of heat treatment and oxygen plasma etching of a close-packed latex particle monolayer is shown to create open-spaced particle templates which facilitates the formation of ordered fully connected liquid bridge networks that are critical to the formation of ordered microwire networks. Similar results can also be achieved if non-close-packed latex particle templates with square or honeycomb geometries are used. The present results have important implications for the development of the particulate templates to control the morphology of functional microwire networks by evaporative lithography.

  7. Statement of Bureau representative [template] [Laguna Atascosa National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This document is a template used for the statement of the bureau representative and the public hearing for the Laguna Atascosa National Wildlife Refuge Wilderness...

  8. Dental rehabilitation of amelogenesis imperfecta using thermoformed templates.

    Science.gov (United States)

    Sockalingam, Snmp

    2011-01-01

    Amelogenesis imperfecta represents a group of dental developmental conditions that are genomic in origin. Hypoplastic AI, hypomineralised AI or both in combination were the most common types seen clinically. This paper describes oral rehabilitation of a 9-year-old Malay girl with inherited hypoplastic AI using transparent thermoforming templates. The defective surface areas were reconstructed to their original dimensions on stone cast models of the upper and lower arches using composite, and transparent thermoform templates were fabricated on the models. The templates were used as crown formers to reconstruct the defective teeth clinically using esthetically matching composite. The usage of the templates allowed direct light curing of the composite, accurate reproducibility of the anatomic contours of the defective teeth, reduced chair-side time and easy contouring and placement of homogenous thickness of composite in otherwise inaccessible sites of the affected teeth.

  9. A concatenated coding scheme for biometric template protection

    NARCIS (Netherlands)

    Shao, Xiaoying; Xu, Haiyun; Veldhuis, Raymond N.J.; Slump, Cornelis H.

    2012-01-01

    Cryptography may mitigate the privacy problem in biometric recognition systems. However, cryptography technologies lack error-tolerance and biometric samples cannot be reproduced exactly, rising the robustness problem. The biometric template protection system needs a good feature extraction algorith

  10. Ordered Nanomaterials Thin Films via Supported Anodized Alumina Templates

    Directory of Open Access Journals (Sweden)

    Mohammed eES-SOUNI

    2014-10-01

    Full Text Available Supported anodized alumina template films with highly ordered porosity are best suited for fabricating large area ordered nanostructures with tunable dimensions and aspect ratios. In this paper we first discuss important issues for the generation of such templates, including required properties of the Al/Ti/Au/Ti thin film heterostructure on a substrate for high quality templates. We then show examples of anisotropic nanostructure films consisting of noble metals using these templates, discuss briefly their optical properties and their applications to molecular detection using surface enhanced Raman spectroscopy. Finally we briefly address the possibility to make nanocomposite films, exemplary shown on a plasmonic-thermochromic nanocomposite of VO2-capped Au-nanorods.

  11. Incorporating User Input in Template-Based Segmentation.

    Science.gov (United States)

    Vidal, Camille; Beggs, Dale; Younes, Laurent; Jain, Sanjay K; Jedynak, Bruno

    2011-01-01

    We present a simple and elegant method to incorporate user input in a template-based segmentation method for diseased organs. The user provides a partial segmentation of the organ of interest, which is used to guide the template towards its target. The user also highlights some elements of the background that should be excluded from the final segmentation. We derive by likelihood maximization a registration algorithm from a simple statistical image model in which the user labels are modeled as Bernoulli random variables. The resulting registration algorithm minimizes the sum of square differences between the binary template and the user labels, while preventing the template from shrinking, and penalizing for the inclusion of background elements into the final segmentation. We assess the performance of the proposed algorithm on synthetic images in which the amount of user annotation is controlled. We demonstrate our algorithm on the segmentation of the lungs of Mycobacterium tuberculosis infected mice from μCT images.

  12. A Survey On Various Web Template Detection And Extraction Methods

    Directory of Open Access Journals (Sweden)

    Neethu Mary Varghese

    2015-03-01

    Full Text Available Abstract In todays digital world reliance on the World Wide Web as a source of information is extensive. Users increasingly rely on web based search engines to provide accurate search results on a wide range of topics that interest them. The search engines in turn parse the vast repository of web pages searching for relevant information. However majority of web portals are designed using web templates which are designed to provide consistent look and feel to end users. The presence of these templates however can influence search results leading to inaccurate results being delivered to the users. Therefore to improve the accuracy and reliability of search results identification and removal of web templates from the actual content is essential. A wide range of approaches are commonly employed to achieve this and this paper focuses on the study of the various approaches of template detection and extraction that can be applied across homogenous as well as heterogeneous web pages.

  13. Template-Framework Interactions in Tetraethylammonium-Directed Zeolite Synthesis

    NARCIS (Netherlands)

    Schmidt, Joel E.; Fu, Donglong; Deem, Michael W.; Weckhuysen, Bert M.

    2016-01-01

    Zeolites, having widespread applications in chemical industries, are often synthesized using organic templates. These can be cost-prohibitive, motivating investigations into their role in promoting crystallization. Herein, the relationship between framework structure, chemical composition, synthesis

  14. GPP Webinar: Solar Procurement Templates and Tools for Higher Education

    Science.gov (United States)

    Green Power Partnership webinar on solar procurement for Higher Education which features various tools and templates that schools can use to shape and manage the solar procurement process to a successful outcome.

  15. Template matching techniques in computer vision theory and practice

    CERN Document Server

    Brunelli, Roberto

    2009-01-01

    The detection and recognition of objects in images is a key research topic in the computer vision community.  Within this area, face recognition and interpretation has attracted increasing attention owing to the possibility of unveiling human perception mechanisms, and for the development of practical biometric systems. This book and the accompanying website, focus on template matching, a subset of object recognition techniques of wide applicability, which has proved to be particularly effective for face recognition applications. Using examples from face processing tasks throughout the book to illustrate more general object recognition approaches, Roberto Brunelli: examines the basics of digital image formation, highlighting points critical to the task of template matching;presents basic and  advanced template matching techniques, targeting grey-level images, shapes and point sets;discusses recent pattern classification paradigms from a template matching perspective;illustrates the development of a real fac...

  16. Improving your target-template alignment with MODalign.

    KAUST Repository

    Barbato, Alessandro

    2012-02-04

    SUMMARY: MODalign is an interactive web-based tool aimed at helping protein structure modelers to inspect and manually modify the alignment between the sequences of a target protein and of its template(s). It interactively computes, displays and, upon modification of the target-template alignment, updates the multiple sequence alignments of the two protein families, their conservation score, secondary structure and solvent accessibility values, and local quality scores of the implied three-dimensional model(s). Although it has been designed to simplify the target-template alignment step in modeling, it is suitable for all cases where a sequence alignment needs to be inspected in the context of other biological information. AVAILABILITY AND IMPLEMENTATION: Freely available on the web at http://modorama.biocomputing.it/modalign. Website implemented in HTML and JavaScript with all major browsers supported. CONTACT: jan.kosinski@uniroma1.it.

  17. A generic process template for continuous pharmaceutical production

    DEFF Research Database (Denmark)

    Singh, Ravendra; Rozada-Sanches, Raquel; Dean, William

    2012-01-01

    In the work reported here, a conceptual generic continuous process template for pharmaceutical production is presented. The template is demonstrated on a nitro reduction case study that should in principle be generic such that it can handle a series of substrates with similar molecular...... for safer operations (from 50 to 100 L in batch or 3 to 5 L in continuous processes). It is shown that the use of the template together with SAM can lead to potential savings in product development times through flexible and efficient production of Kg amounts of product material for clinical trials...... functionality. To assist in adoption of different substrates, a systematic substrate adoption methodology (SAM) has also been developed. The objective of the generic process template together with the SAM is to provide flexibility as well as increased efficiency to continuous processes while reducing inventory...

  18. Alumina Template-Dependant Growth of Cobalt Nanowire Arrays

    Directory of Open Access Journals (Sweden)

    L. Malferrari

    2009-01-01

    Full Text Available Different electrochemical regimes and porous alumina were applied for template synthesis of cobalt nanowire (nw arrays, revealing several peculiar cases. In contrast to quite uniform filling of sulfuric acid alumina templates by alternating current deposition, nonuniform growth of the Co nw tufts and mushrooms was obtained for the case of oxalic acid templates. We showed herein for the first time that such configurations arise from the spontaneous growth of cobalt nw groups evolving from the cobalt balls at the Al/alumina interface. Nevertheless, the uniform growth of densely packed cobalt nw arrays, up to tens of micrometers in length, was obtained via long-term direct current galvanostatic deposition at low current density using oxalic acid templates one-side coated by conducting layer. The unique point of this regime is the formation of hexagonal lattice Co nws with a preferred (100 growth direction.

  19. Dental rehabilitation of amelogenesis imperfecta using thermoformed templates

    Directory of Open Access Journals (Sweden)

    SNMP Sockalingam

    2011-01-01

    Full Text Available Amelogenesis imperfecta represents a group of dental developmental conditions that are genomic in origin. Hypoplastic AI, hypomineralised AI or both in combination were the most common types seen clinically. This paper describes oral rehabilitation of a 9-year-old Malay girl with inherited hypoplastic AI using transparent thermoforming templates. The defective surface areas were reconstructed to their original dimensions on stone cast models of the upper and lower arches using composite, and transparent thermoform templates were fabricated on the models. The templates were used as crown formers to reconstruct the defective teeth clinically using esthetically matching composite. The usage of the templates allowed direct light curing of the composite, accurate reproducibility of the anatomic contours of the defective teeth, reduced chair-side time and easy contouring and placement of homogenous thickness of composite in otherwise inaccessible sites of the affected teeth.

  20. [A method for DNA template preparation using a single embryo].

    Science.gov (United States)

    Li, Jun-Feng; Li, Hai-Feng; Song, Yan-Hua; Sun, Yan; Zhang, Jia-Hua

    2005-09-01

    We established a simple method for the preparation of DNA template from a single oocyte or early embryo by KOH/DTT-Triton X disintegration. The PCR amplification efficiency of DNA template prepared by this method was compared with that prepared by TE-proteinase K. Single oocyte, 2-cell embryo, 8-cell embryo, morula or blastocyst were separately treated by KOH/DTT-Triton X, then the DNA template was directly used to amplify mitochondrial DNA segment by PCR. The overall PCR success rate of the 3 pairs of primers was 100% (70/70), while the overall PCR success rate of single oocyte treated by TE-proteinase K was 92.9% (65/70). Difference between the two results was significant (PDNA template of a single early embryo. It needed only one cycle of PCR amplification to get clear aimed DNA stripe and the efficiency was high enough to meet the need of early embryonic genetic material detection.

  1. Indirect bonding technique in orthodontics

    Directory of Open Access Journals (Sweden)

    Kübra Yıldırım

    2016-08-01

    Full Text Available ‘Direct Bonding Technique’ which allows the fixed orthodontic appliances to be directly bonded to teeth without using bands decreased the clinic time for bracket bonding and increased esthetics and oral hygiene during orthodontic treatment. However, mistakes in bracket positioning were observed due to decreased direct visual sight and access to posterior teeth. ‘Indirect Bonding Technique’ was developed for eliminating these problems. Initially, decreased bond strength, higher bond failure rate, periodontal tissue irritation, compromised oral hygiene and increased laboratory time were the main disadvantages of this technique when compared to direct bonding. The newly developed materials and modified techniques help to eliminate these negative consequences. Today, the brackets bonded with indirect technique have similar bond strength with brackets bonded directly. Moreover, indirect and direct bonding techniques have similar effects on periodontal tissues. However, indirect bonding technique requires more attention and precision in laboratory and clinical stage, and has higher cost. Orthodontist's preference between these two bonding techniques may differ according to time spent in laboratory and clinic, cost, patient comfort and personal opinion.

  2. Biotic Control of Surface pH and Evidence of Light-Induced H+ Pumping and Ca2+-H+ Exchange in a Tropical Crustose Coralline Alga.

    Science.gov (United States)

    Hofmann, Laurie C; Koch, Marguerite; de Beer, Dirk

    2016-01-01

    Presently, an incomplete mechanistic understanding of tropical reef macroalgae photosynthesis and calcification restricts predictions of how these important autotrophs will respond to global change. Therefore, we investigated the mechanistic link between inorganic carbon uptake pathways, photosynthesis and calcification in a tropical crustose coralline alga (CCA) using microsensors. We measured pH, oxygen (O2), and calcium (Ca2+) dynamics and fluxes at the thallus surface under ambient (8.1) and low (7.8) seawater pH (pHSW) and across a range of irradiances. Acetazolamide (AZ) was used to inhibit extracellular carbonic anhydrase (CAext), which mediates hydrolysis of HCO3-, and 4,4' diisothiocyanatostilbene-2,2'-disulphonate (DIDS) that blocks direct HCO3- uptake by anion exchange transport. Both inhibited photosynthesis, suggesting both diffusive uptake of CO2 via HCO3- hydrolysis to CO2 and direct HCO3- ion transport are important in this CCA. Surface pH was raised approximately 0.3 units at saturating irradiance, but less when CAext was inhibited. Surface pH was lower at pHSW 7.8 than pHSW 8.1 in the dark, but not in the light. The Ca2+ fluxes were large, complex and temporally variable, but revealed net Ca2+ uptake under all conditions. The temporal variability in Ca2+ dynamics was potentially related to localized dissolution during epithallial cell sloughing, a strategy of CCA to remove epiphytes. Simultaneous Ca2+ and pH dynamics suggest the presence of Ca2+/H+ exchange. Rapid light-induced H+ surface dynamics that continued after inhibition of photosynthesis revealed the presence of a light-mediated, but photosynthesis-independent, proton pump. Thus, the study indicates metabolic control of surface pH can occur in CCA through photosynthesis and light-inducible H+ pumps. Our results suggest that complex light-induced ion pumps play an important role in biological processes related to inorganic carbon uptake and calcification in CCA.

  3. Biotic Control of Surface pH and Evidence of Light-Induced H+ Pumping and Ca2+-H+ Exchange in a Tropical Crustose Coralline Alga.

    Directory of Open Access Journals (Sweden)

    Laurie C Hofmann

    Full Text Available Presently, an incomplete mechanistic understanding of tropical reef macroalgae photosynthesis and calcification restricts predictions of how these important autotrophs will respond to global change. Therefore, we investigated the mechanistic link between inorganic carbon uptake pathways, photosynthesis and calcification in a tropical crustose coralline alga (CCA using microsensors. We measured pH, oxygen (O2, and calcium (Ca2+ dynamics and fluxes at the thallus surface under ambient (8.1 and low (7.8 seawater pH (pHSW and across a range of irradiances. Acetazolamide (AZ was used to inhibit extracellular carbonic anhydrase (CAext, which mediates hydrolysis of HCO3-, and 4,4' diisothiocyanatostilbene-2,2'-disulphonate (DIDS that blocks direct HCO3- uptake by anion exchange transport. Both inhibited photosynthesis, suggesting both diffusive uptake of CO2 via HCO3- hydrolysis to CO2 and direct HCO3- ion transport are important in this CCA. Surface pH was raised approximately 0.3 units at saturating irradiance, but less when CAext was inhibited. Surface pH was lower at pHSW 7.8 than pHSW 8.1 in the dark, but not in the light. The Ca2+ fluxes were large, complex and temporally variable, but revealed net Ca2+ uptake under all conditions. The temporal variability in Ca2+ dynamics was potentially related to localized dissolution during epithallial cell sloughing, a strategy of CCA to remove epiphytes. Simultaneous Ca2+ and pH dynamics suggest the presence of Ca2+/H+ exchange. Rapid light-induced H+ surface dynamics that continued after inhibition of photosynthesis revealed the presence of a light-mediated, but photosynthesis-independent, proton pump. Thus, the study indicates metabolic control of surface pH can occur in CCA through photosynthesis and light-inducible H+ pumps. Our results suggest that complex light-induced ion pumps play an important role in biological processes related to inorganic carbon uptake and calcification in CCA.

  4. The need of appropriate brain SPECT templates for SPM comparisons

    Energy Technology Data Exchange (ETDEWEB)

    Morbelli, S.; Altrinetti, V.; Piccardo, A. [S Martino Univ Hosp, Nucl MedUnit DIMI, I-16132 Genoa (Italy); Rodriguez, G.; Brugnolo, A.; Nobili, F. [S Martino Univ Hosp, Clin Neurophysiol Unit DiSEM, DiTeC, I-16132 Genoa (Italy); Mignone, A. [Osped Riuniti Bergamo, Nucl Med Unit, I-24100 Bergamo (Italy); Pupi, A. [Univ Florence, Nucl Med Unit DFP, Florence (Italy); Koulibaly, P.M. [CEA-Univ Nice Sophia Antipolis, TIRO, Dept Nucl Med, Ctr Antoine Lacassagne, Nice (France)

    2008-07-01

    Statistical parametric mapping (SPM) is used worldwide to compare brain perfusion single photon emission computed tomography (SPECT) data. The default template within the SPM package used for SPECT image normalization includes images of a group of healthy subjects studied with {sup 99m}TcHMPAO. Since [{sup 99m}Tc] HMPAO and [{sup 99m}Tc] ECD have shown to distribute differently in SPECT studies, we formulated the hypothesis that comparing set of [{sup 99m}Tc]ECD data normalized by means of a [{sup 99m}Tc]HMPAO template may lead to incorrect results. A customized [{sup 99m}Tc]ECD template was built with SPECT and magnetic resonance imaging (MRI) images of 22 neurologically healthy women. Then, two sets of subjects, i.e. a group of patients with very early Alzheimer's disease (eAD) and a matched control group, studied by means of [{sup 99m}Tc]ECD SPECT, were chosen for comparisons. The same statistical approach (t-test between eAD patients and controls and correlation analysis between brain SPECT and a cognitive score) was applied twice, i.e. after normalization with either the default [{sup 99m}Tc]HMPAO template or the customized [{sup 99m}Tc]ECD template. In the comparison between eAD and controls, a cluster of difference in the posterior-cingulate gyrus of both hemispheres was only highlighted when using the customized [{sup 99m}Tc]ECD template, but was missed when using the default [{sup 99m}Tc]HMPAO template. In the correlation between brain perfusion and a cognitive score, the significant cluster was more significant and far more extended, also including the right superior temporal gyrus, using the customized [{sup 99m}Tc]ECD template than using the default [{sup 99m}Tc]HMPAO template. These data suggest the need of customized, radiopharmaceutical-matched SPECT templates to be used within the SPM package. The present customized [{sup 99m}Tc]ECD template is now freely available on the web. (authors)

  5. Track finding with deformable templates — the elastic arms approach

    Science.gov (United States)

    Ohlsson, Mattias; Peterson, Carsten; Yuille, Alan L.

    1992-08-01

    A novel algorithm for particle tracking is presented and evaluated. It is based on deformable templates that converge using a deterministic annealing algorithm. These deformable templates are initialized by Hough transforms. The algorithm, which effectively represents a merger between neuronic decision making and parameter fitting, naturally lends itself to parallel execution. Very good performance is obtained for both non-magnetic and magnetic tracks. For the latter simulated TPC tracks from the CERN DELPHI detector are used.

  6. An Empirical Ultraviolet Iron Spectrum Template Applicable to Active Galaxies

    DEFF Research Database (Denmark)

    Vestergaard, Marianne; Wilkes, B. J.

    2001-01-01

    Iron emission is often a severe contaminant in optical-ultraviolet spectra of active galaxies. Its presence complicates emission line studies. A viable solution, already successfully applied at optical wavelengths, is to use an empirical iron emission template. We have generated FeII and FeIII te......, including iron transitions. Details of the data processing, generation, and use of the templates, are given by Vestergaard & Wilkes (2001)....

  7. Chemical Strategies for Template Syntheses of Composite Micro and Nanostructures.

    Science.gov (United States)

    2007-11-02

    syntheses can be accomplished within the pores of the alumina templates to make semiconductor tubules (27). Figure 5 shows that Ti02 tubules prepared...surface area forms have higher photo efficiencies (28). Ti02 /conductor nanocomposites may prove to be useful photocatalysts because the template...synthesized Ti02 nanostructures have very high surface areas (27). Furthermore, as discussed previously, each outer tubular Ti02 catalyst particle has

  8. Templating as a Chain of Custody Tool for Arms Control

    Energy Technology Data Exchange (ETDEWEB)

    Benz, Jacob M.; Tanner, Jennifer E.; Duckworth, Leesa L.

    2013-06-01

    Historically, templates have been considered for use as a treaty accountable item (TAI) authentication tool, alongside item attributes. Because of this, the use of templates has fallen by the wayside due to the perceived intrusiveness of and handling/storage of template data; especially when compared to the negotiability of unclassified attribute threshold values. However, as a chain of custody tool, templates potentially have a large and important role to play in maintaining confidence in the authenticity of the treaty accountable items as they progress through an arms control regime. In general terms, templating is the process of creating a unique, measurable, and repeatable signature which is representative of the TAI. At any point in time, the signature can be re-measured or re-inspected to verify the signature has not changed. Chain of custody is the process by which a controlled boundary is established and maintained around a TAI to both deter and detect unauthorized access to the item. Typically, this is accomplished by putting a tamper indicating device (TID) on the item or container. The TID now acts as a surrogate for the item itself, and is continually checked to ensure the unique identifier and tamper indicating mechanisms have not changed since last inspection. This in and of itself is a form of templating. A stronger template is one that utilizes a signature of the combined item and container. There are many potential signatures which may be exploited, including radiation-, electromagnetic-, and acoustic-based signatures. This paper/presentation will explore the technology and mechanisms in which templating can be applied to create a more robust chain of custody over treaty accountable items as part of a future arms control regime.

  9. Preparation of mesoporous aluminophosphate usingpoly(amido amine) as template

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xiaofeng; LIN Shen; CHEN Xinqing; CHEN Jiebo; YANG Liuyi; LUO Minghong

    2007-01-01

    Mesoporous aluminophosphate was prepared by using G4.0 poly(amido amine)dendrimer as a template and characterized by Fourier transform infrared spectrometer(FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM) and N2 adsorption/desorption methods.Results show that the title compound exhibits a typical mesoporous structure with the average pore size from 5 to 8 nm. The formation mechanism of the nanoporous structure using dendrimer as a template was also discussed.

  10. II - Template Metaprogramming for Massively Parallel Scientific Computing - Vectorization with Expression Templates

    CERN Document Server

    CERN. Geneva

    2016-01-01

    Large scale scientific computing raises questions on different levels ranging from the fomulation of the problems to the choice of the best algorithms and their implementation for a specific platform. There are similarities in these different topics that can be exploited by modern-style C++ template metaprogramming techniques to produce readable, maintainable and generic code. Traditional low-level code tend to be fast but platform-dependent, and it obfuscates the meaning of the algorithm. On the other hand, object-oriented approach is nice to read, but may come with an inherent performance penalty. These lectures aim to present he basics of the Expression Template (ET) idiom which allows us to keep the object-oriented approach without sacrificing performance. We will in particular show to to enhance ET to include SIMD vectorization. We will then introduce techniques for abstracting iteration, and introduce thread-level parallelism for use in heavy data-centric loads. We will show to to apply these methods i...

  11. III - Template Metaprogramming for massively parallel scientific computing - Templates for Iteration; Thread-level Parallelism

    CERN Document Server

    CERN. Geneva

    2016-01-01

    Large scale scientific computing raises questions on different levels ranging from the fomulation of the problems to the choice of the best algorithms and their implementation for a specific platform. There are similarities in these different topics that can be exploited by modern-style C++ template metaprogramming techniques to produce readable, maintainable and generic code. Traditional low-level code tend to be fast but platform-dependent, and it obfuscates the meaning of the algorithm. On the other hand, object-oriented approach is nice to read, but may come with an inherent performance penalty. These lectures aim to present he basics of the Expression Template (ET) idiom which allows us to keep the object-oriented approach without sacrificing performance. We will in particular show to to enhance ET to include SIMD vectorization. We will then introduce techniques for abstracting iteration, and introduce thread-level parallelism for use in heavy data-centric loads. We will show to to apply these methods i...

  12. Silver nanowires-templated metal oxide for broadband Schottky photodetector

    Science.gov (United States)

    Patel, Malkeshkumar; Kim, Hong-Sik; Park, Hyeong-Ho; Kim, Joondong

    2016-04-01

    Silver nanowires (AgNWs)-templated transparent metal oxide layer was applied for Si Schottky junction device, which remarked the record fastest photoresponse of 3.4 μs. Self-operating AgNWs-templated Schottky photodetector showed broad wavelength photodetection with high responsivity (42.4 A W-1) and detectivity (2.75 × 1015 Jones). AgNWs-templated indium-tin-oxide (ITO) showed band-to-band excitation due to the internal photoemission, resulting in significant carrier collection performances. Functional metal oxide layer was formed by AgNWs-templated from ITO structure. The grown ITO above AgNWs has a cylindrical shape and acts as a thermal protector of AgNWs for high temperature environment without any deformation. We developed thermal stable AgNWs-templated transparent oxide devices and demonstrated the working mechanism of AgNWs-templated Schottky devices. We may propose the high potential of hybrid transparent layer design for various photoelectric applications, including solar cells.

  13. A Geometric Particle Filter for Template-Based Visual Tracking.

    Science.gov (United States)

    Junghyun Kwon; Hee Seok Lee; Park, Frank C; Kyoung Mu Lee

    2014-04-01

    Existing approaches to template-based visual tracking, in which the objective is to continuously estimate the spatial transformation parameters of an object template over video frames, have primarily been based on deterministic optimization, which as is well-known can result in convergence to local optima. To overcome this limitation of the deterministic optimization approach, in this paper we present a novel particle filtering approach to template-based visual tracking. We formulate the problem as a particle filtering problem on matrix Lie groups, specifically the three-dimensional Special Linear group SL(3) and the two-dimensional affine group Aff(2). Computational performance and robustness are enhanced through a number of features: (i) Gaussian importance functions on the groups are iteratively constructed via local linearization; (ii) the inverse formulation of the Jacobian calculation is used; (iii) template resizing is performed; and (iv) parent-child particles are developed and used. Extensive experimental results using challenging video sequences demonstrate the enhanced performance and robustness of our particle filtering-based approach to template-based visual tracking. We also show that our approach outperforms several state-of-the-art template-based visual tracking methods via experiments using the publicly available benchmark data set.

  14. Geometric Templates for Improved Tracking Performance in Monte Carlo Codes

    Science.gov (United States)

    Nease, Brian R.; Millman, David L.; Griesheimer, David P.; Gill, Daniel F.

    2014-06-01

    One of the most fundamental parts of a Monte Carlo code is its geometry kernel. This kernel not only affects particle tracking (i.e., run-time performance), but also shapes how users will input models and collect results for later analyses. A new framework based on geometric templates is proposed that optimizes performance (in terms of tracking speed and memory usage) and simplifies user input for large scale models. While some aspects of this approach currently exist in different Monte Carlo codes, the optimization aspect has not been investigated or applied. If Monte Carlo codes are to be realistically used for full core analysis and design, this type of optimization will be necessary. This paper describes the new approach and the implementation of two template types in MC21: a repeated ellipse template and a box template. Several different models are tested to highlight the performance gains that can be achieved using these templates. Though the exact gains are naturally problem dependent, results show that runtime and memory usage can be significantly reduced when using templates, even as problems reach realistic model sizes.

  15. The Affordance Template ROS Package for Robot Task Programming

    Science.gov (United States)

    Hart, Stephen; Dinh, Paul; Hambuchen, Kimberly

    2015-01-01

    This paper introduces the Affordance Template ROS package for quickly programming, adjusting, and executing robot applications in the ROS RViz environment. This package extends the capabilities of RViz interactive markers by allowing an operator to specify multiple end-effector waypoint locations and grasp poses in object-centric coordinate frames and to adjust these waypoints in order to meet the run-time demands of the task (specifically, object scale and location). The Affordance Template package stores task specifications in a robot-agnostic XML description format such that it is trivial to apply a template to a new robot. As such, the Affordance Template package provides a robot-generic ROS tool appropriate for building semi-autonomous, manipulation-based applications. Affordance Templates were developed by the NASA-JSC DARPA Robotics Challenge (DRC) team and have since successfully been deployed on multiple platforms including the NASA Valkyrie and Robonaut 2 humanoids, the University of Texas Dreamer robot and the Willow Garage PR2. In this paper, the specification and implementation of the affordance template package is introduced and demonstrated through examples for wheel (valve) turning, pick-and-place, and drill grasping, evincing its utility and flexibility for a wide variety of robot applications.

  16. China-Russia Bond

    Institute of Scientific and Technical Information of China (English)

    Ji Zhiye; Ma Zongshi

    2007-01-01

    @@ Thanks to China's successful launching of the Year of Russia, 2006 will surely go down as a milestone in the history of the China-Russia bond. Furthermore, a still-warmer climate will continue to prevail in 2007 when Moscow, in its turn, hosts the Year of China, trying to outshine its next-door neighbor in this regard, as Russian President Vladimir Putin promised in the exchange of new year greetings with his Chinese counterpart, President Hu Jintao.

  17. Small-molecule recognition for controlling molecular motion in hydrogen-bond-assembled rotaxanes.

    Science.gov (United States)

    Martinez-Cuezva, Alberto; Berna, Jose; Orenes, Raul-Angel; Pastor, Aurelia; Alajarin, Mateo

    2014-06-23

    Di(acylamino)pyridines successfully template the formation of hydrogen-bonded rotaxanes through five-component clipping reactions. A solid-state study showed the participation of the pyridine nitrogen atom in the stabilization of the mechanical bond between the thread and the benzylic amide macrocycle. The addition of external complementary binders to a series of interlocked bis(2,6-di(acylamino)pyridines) promoted restraint of the back and forward ring motion. The original translation can be restored through a competitive recognition event by the addition of a preorganized bis(di(acylamino)pyridine) that forms stronger ADA-DAD complexes with the external binders.

  18. Direct bonded space maintainers.

    Science.gov (United States)

    Santos, V L; Almeida, M A; Mello, H S; Keith, O

    1993-01-01

    The aim of this study was to evaluate clinically a bonded space maintainer, which would reduce chair-side time and cost. Sixty appliances were fabricated from 0.7 mm stainless steel round wire and bonded using light-cured composite to the two teeth adjacent to the site of extraction of a posterior primary tooth. Twenty males and sixteen females (age range 5-9-years-old) were selected from the Pedodontic clinic of the State University of Rio de Janeiro. The sixty space maintainers were divided into two groups according to the site in which they were placed: a) absent first primary molar and b) absent second primary molar. Impressions and study models were obtained prior to and 6 months after bonding the appliances. During this period only 8.3% of failures were observed, most of them from occlusal or facial trauma. Student t-test did not show statistically significant alterations in the sizes of the maintained spaces during the trial period.

  19. Application of quantitative light-induced fluorescence to determine the depth of demineralization of dental fluorosis in enamel microabrasion: a case report.

    Science.gov (United States)

    Park, Tae-Young; Choi, Han-Sol; Ku, Hee-Won; Kim, Hyun-Su; Lee, Yoo-Jin; Min, Jeong-Bum

    2016-08-01

    Enamel microabrasion has become accepted as a conservative, nonrestorative method of removing intrinsic and superficial dysmineralization defects from dental fluorosis, restoring esthetics with minimal loss of enamel. However, it can be difficult to determine if restoration is necessary in dental fluorosis, because the lesion depth is often not easily recognized. This case report presents a method for analysis of enamel hypoplasia that uses quantitative light-induced fluorescence (QLF) followed by a combination of enamel microabrasion with carbamide peroxide home bleaching. We describe the utility of QLF when selecting a conservative treatment plan and confirming treatment efficacy. In this case, the treatment plan was based on QLF analysis, and the selected combination treatment of microabrasion and bleaching had good results.

  20. Light-induced structural changes in photosynthetic reaction centres studied by ESEEM of spin-correlated D+QA- radical pairs.

    Science.gov (United States)

    Borovykh, I V; Dzuba, S A; Proskuryakov, I I; Gast, P; Hoff, A J

    1998-03-25

    Zn-substituted Rhodobacter sphaeroides R26 reaction centres (RCs) frozen in the dark and under illumination exhibit quite different recombination kinetics of the D+QA- radical pairs [Kleinfeld et al., Biochemistry, 23 (1984) 5780]. We have applied electron spin echo envelope modulation (ESEEM) of the spin-correlated D+QA- radical pairs to assess a possible light-induced change in the distance between the D and QA cofactors. The recombination kinetics and the field-swept spin-polarized EPR signal for the two preparations have been monitored by time-resolved EPR spectroscopy. For the samples frozen under illumination, a slight increase in the distance, 0.4+/-0.2 A, has been detected.

  1. In situ visualizing the evolution of the light-induced refractive index change of Mn:KLTN crystal with digital holographic interferometry

    Directory of Open Access Journals (Sweden)

    Jinxin Han

    2015-04-01

    Full Text Available The light-induced refractive index change in Mn:KLTN crystal, illuminated by focused light sheet, is visualized in situ and quantified by digital holographic interferometry. By numerically retrieving a series of sequential phase maps from recording digital holograms, the spatial distribution of the induced refractive index change can be visualized and estimated readily. This technique enables the observation of the temporal evolution of the refractive index change under different recording situations such as writing laser power, applied voltage, and temperature, and the photoconductivity of Mn:KLTN crystal can be calculated as well, the experimental results are in good agreement with the theory. The research results suggest that the presented method is successful and feasible.

  2. Visible-light-induced, Ir-catalyzed reactions of N-methyl-N-((trimethylsilylmethylaniline with cyclic α,β-unsaturated carbonyl compounds

    Directory of Open Access Journals (Sweden)

    Dominik Lenhart

    2014-04-01

    Full Text Available N-Methyl-N-((trimethylsilylmethylaniline was employed as reagent in visible-light-induced, iridium-catalyzed addition reactions to cyclic α,β-unsaturated carbonyl compounds. Typical reaction conditions included the use of one equivalent of the reaction substrate, 1.5 equivalents of the aniline and 2.5 mol % (in MeOH or 1.0 mol % (in CH2Cl2 [Ir(ppy2(dtbbpy]BF4 as the catalyst. Two major reaction products were obtained in combined yields of 30–67%. One product resulted from aminomethyl radical addition, the other product was a tricyclic compound, which is likely formed by attack of the intermediately formed α-carbonyl radical at the phenyl ring. For five-membered α,β-unsaturated lactone and lactam substrates, the latter products were the only products isolated. For the six-membered lactones and lactams and for cyclopentenone the simple addition products prevailed.

  3. Visible Light-induced Cr-doped SrTiO3-g-C3N4 Composite for Improved Photocatalytic Performance

    Institute of Scientific and Technical Information of China (English)

    YANG Ming; JIN Xiaoqi

    2014-01-01

    Novel visible light-induced Cr-doped SrTiO3-g-C3N4 composite photocatalysts were synthesized by introducing polymeric g-C3N4. The composite photocatalyst was characterized by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), Fourier transform infrared (FT-IR) spectroscopy, UV-vis diffuse reflection spectroscopy, photoluminescence (PL) spectroscopy and BET surface area measurements. The photocatalytic oxidation ability of the novel composite photocatalyst was evaluated using methyl orange (MO) as a target pollutant. The photocatalysts exhibited a significantly enhanced photocatalytic performance in degrading MO. The optimal g-C3N4 content for the photodegradation activity of the composite photocatalysts was determined. The as-prepared composite photocatalyst exhibits an improved photocatalytic activity due to enhancement of photo-generated electron-hole separation at the interface.

  4. Application of quantitative light-induced fluorescence to determine the depth of demineralization of dental fluorosis in enamel microabrasion: a case report

    Science.gov (United States)

    Park, Tae-Young; Choi, Han-Sol; Ku, Hee-Won; Kim, Hyun-Su; Lee, Yoo-Jin

    2016-01-01

    Enamel microabrasion has become accepted as a conservative, nonrestorative method of removing intrinsic and superficial dysmineralization defects from dental fluorosis, restoring esthetics with minimal loss of enamel. However, it can be difficult to determine if restoration is necessary in dental fluorosis, because the lesion depth is often not easily recognized. This case report presents a method for analysis of enamel hypoplasia that uses quantitative light-induced fluorescence (QLF) followed by a combination of enamel microabrasion with carbamide peroxide home bleaching. We describe the utility of QLF when selecting a conservative treatment plan and confirming treatment efficacy. In this case, the treatment plan was based on QLF analysis, and the selected combination treatment of microabrasion and bleaching had good results. PMID:27508165

  5. Synthesis, Crystal Structure, Solid Photochromic Properties and Light-induced Radical Behavior of Bis(3-[alkyl/(palkoxyphenyl)]-3-hydroxyindan-1-on-2-ylidene) Derivatives

    Institute of Scientific and Technical Information of China (English)

    HAN Jie; WANG Chang-Qing; WEI Yong-Heng; PANG Mei-Li; MENG Ji-Ben

    2008-01-01

    A series of new bis{3-[alkyl/(p-alkoxyphenyl)]-3-hydroxyindan-1-on-2-ylidene} derivatives 1-6 were prepared and characterized fully by 1H NMR, IR, MS and elemental analysis data. The structures of compounds 1, 5 and 6 were confurmed by the single-crystal X-ray diffraction. The photochromic and light-induced properties were examined by means of UV-Vis and electron spin resonance (ESR) spectroscopy methods, respectively. The results show that all the title compounds in this work simultaneously exhibit photochromism in solid state and generate stable free radicals under irradiation with a 200 W high pressure Hg-lamp. Structure-property relationship within these photochromic compounds was discussed in the context of their molecular structures and intra-molecular interactions.

  6. Preparation of fluorescein-functionalized electrospun fibers coated with TiO{sub 2} and gold nanoparticles for visible-light-induced photocatalysis

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Won Suk [Department of Chemistry, Hannam University, Daejeon 306-791 (Korea, Republic of); Choi, Insung S. [Department of Chemistry, KAIST, Daejeon 305-701 (Korea, Republic of); Lee, Jungkyu K., E-mail: jkl@knu.ac.kr [Molecular-Level Interface Research Center, Department of Chemistry and Green-Nano Research Center, Kyungpook National University, Daegu 702-701 (Korea, Republic of); Yoon, Kuk Ro, E-mail: kryoon@hannam.ac.kr [Department of Chemistry, Hannam University, Daejeon 306-791 (Korea, Republic of)

    2015-08-01

    We demonstrated a new type of visible light-induced photocatalyst, comprising fluorescein molecules, TiO{sub 2}, and gold nanoparticles anchored onto polymer fibers. The synthesized fiber composite was fully characterized by thermogravimetric analysis, scanning electron microscopy, transmission electron microscopy, FT-IR spectroscopy, contact angle measurement, and fluorescence microscopy. Under sunlight and visible light irradiation, the photocatalytic activity of the tricomponent system showed 2–3 times greater photodegradation efficiency for methylene blue than a representative photocatalyst, Degussa P25. - Graphical abstract: PSS/PAH-FITC/TiO{sub 2}/AuNP composite demonstrated 2–3 times greater visible light photodegradation efficiency for methylene blue than a representative photocatalyst, Degussa P25. Display Omitted - Highlights: • Synthesis of a novel composite, polymer fiber/organic dye/TiO{sub 2}/gold nanoparticles. • The composite was characterized by TGA, SEM, TEM, and fluorescence microscopy. • Improved visible light photocatalytic activity of the sythesized novel composite.

  7. Indication of transthylakoid proton-fluxes in Aegopodium podagraria L. by light-induced changes of plasmalemma potential, chlorophyll fluorescence and light-scattering.

    Science.gov (United States)

    Vanselow, K H; Dau, H; Hansen, U P

    1988-12-01

    The time course of the responses of chlorophyll fluorescence in leaves of Aegopodium podagraria to changes in irradiance does not necessarily show the time constant of thylakoid energization at energy fluence rates below 10-25 W·m(-2). In addition, other measures of thylakoid energization, such as lightscattering at 532 nm and the responses to saturating flashes, show that the related component disappears from these signals at low fluence rates, but not necessarily all together at the same fluence rate. However, this time constant still appears in the light-induced responses of the plasmalemma potential. This implies that the effect on the electrogenic proton pump in the plasmalemma is the most sensitive indicator of proton fluxes into the inner thylakoid space. These results are a further indication that energy-quenching is coupled ther indication that energy-quenching is coupled to transthylakoid proton fluxes via an intermediate, which is not active in Aegopodium podagraria at low irradiances.

  8. Optimal Investment in Structured Bonds

    DEFF Research Database (Denmark)

    Jessen, Pernille; Jørgensen, Peter Løchte

    The paper examines the role of structured bonds in the optimal portfolio of a small retail investor. We consider the typical structured bond essentially repacking an exotic option and a zero coupon bond, i.e. an investment with portfolio insurance. The optimal portfolio is found when the investment...

  9. Coulombic Models in Chemical Bonding.

    Science.gov (United States)

    Sacks, Lawrence J.

    1986-01-01

    Compares the coulumbic point charge model for hydrogen chloride with the valence bond model. It is not possible to assign either a nonpolar or ionic canonical form of the valence bond model, while the covalent-ionic bond distribution does conform to the point charge model. (JM)

  10. Effect of Organic Solvents and Biologically Relevant Ions on the Light-Induced DNA Cleavage by Pyrene and Its Amino and Hydroxy Derivatives

    Directory of Open Access Journals (Sweden)

    Hongtao Yu

    2002-09-01

    Full Text Available Abstract: Polycyclic aromatic hydrocarbons (PAHs are a class of carcinogenic compounds that are both naturally and artificially produced. Many PAHs are pro-carcinogens that require metabolic activation. Recently, it has been shown that PAH can induce DNA single strand cleavage and formation of PAH-DNA covalent adduct upon irradiation with UVA light. The light-induced DNA cleavage parallels phototoxicity in one instance. The DNA photocleavage efficiency depends on the structure of the PAHs. This article reports the effect of both organic solvents and the presence of biologically relevant ions, Na+, Mg2+, Ca2+, K+, Fe3+, Cu2+, Zn+2, Mn2+, and I-, on the light-induced DNA cleavage by pyrene, 1-hydroxypyrene and 1-aminopyrene. Since both 1-hydroxypyrene (0.6 μM and 1-aminopyrene (6 μM dissolve well in the minimum organic solvents used (2% methanol, dimethylsulfoxide, and dimethylformamide, increasing the amount of the organic solvent resulted in the decrease of the amount of DNA single strand cleavage caused by the combination effect of 1-hydroxy or 1-aminopyrene and UVA light. The result with the less watersoluble pyrene shows that increase of the amount of the organic solvent can increase the amount of DNA single strand DNA photocleavage cause by the combination of pyrene and UVA light. Therefore, there are two effects by the organic solvents: (i to dissolve PAH and (ii to quench DNA photocleavage. The presence of Fe3+ and Zn2+ enhances, while the presence of Ca2+ and Mn2+ inhibits the DNA photocleavage caused by 1-aminopyrene and UVA light. Other metal ions have minimal effect. This means that the effect of ions on DNA photocleavage by PAHs is complex. The presence of KI enhances DNA photocleavage. This indicates that the triplet-excited state of 1-aminopyrene is involved in causing DNA cleavage

  11. Light-induced systemic regulation of photosynthesis in primary and trifoliate leaves of Phaseolus vulgaris: effects of photosynthetic photon flux density (PPFD) versus spectrum.

    Science.gov (United States)

    Murakami, K; Matsuda, R; Fujiwara, K

    2014-01-01

    The objectives of this work using Phaseolus vulgaris were to examine whether the light spectrum incident on mature primary leaves (PLs) is related to leaf-to-leaf systemic regulation of developing trifoliate leaves (TLs) in photosynthetic characteristics, and to investigate the relative importance of spectrum and photosynthetic photon flux density (PPFD) in light-induced systemic regulation. Systemic regulation was induced by altering PPFD and the spectrum of light incident on PLs using a shading treatment and lighting treatments including either white, blue, green or red light-emitting diodes (LEDs). Photosynthetic characteristics were evaluated by measuring the light-limited and light-saturated net photosynthetic rates and the amounts of nitrogen (N), chlorophyll (Chl) and ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco; EC 4.1.1.39). Shading treatment on PLs decreased the amounts of N, Chl and Rubisco of TLs and tended to decrease the photosynthetic rates. However, we observed no systemic effects induced by the light spectrum on PLs in this study, except that a higher amount of Rubisco of TLs was observed when the PLs were irradiated with blue LEDs. Our results imply that photoreceptors in mature leaves have little influence on photosynthetic rates and amounts of N and Chl of developing leaves through systemic regulation, although the possibility of the action of blue light irradiation on the amount of Rubisco cannot be ruled out. Based on these results, we concluded that the light spectrum incident on mature leaves has little systemic effect on developing leaves in terms of photosynthetic characteristics and that the light-induced systemic regulation was largely accounted for by PPFD.

  12. Organic materials as templates for the formation of mesoporous inorganic materials and ordered inorganic nanocomposites

    Science.gov (United States)

    Ziegler, Christopher R.

    Hierarchically structured inorganic materials are everywhere in nature. From unicellular aquatic algae such as diatoms to the bones and/or cartilage that comprise the skeletal systems of vertebrates. Complex mechanisms involving site-specific chemistries and precision kinetics are responsible for the formation of such structures. In the synthetic realm, reproduction of even the most basic hierarchical structure effortlessly produced in nature is difficult. However, through the utilization of self-assembling structures or "templates", such as polymers or amphiphilic surfactants, combined with some favorable interaction between a chosen inorganic, the potential exists to imprint an inorganic material with a morphology dictated via synthetic molecular self-assembly. In doing so, a very basic hierarchical structure is formed on the angstrom and nanometer scales. The work presented herein utilizes the self-assembly of either surfactants or block copolymers with the desired inorganic or inorganic precursor to form templated inorganic structures. Specifically, mesoporous silica spheres and copolymer directed calcium phosphate-polymer composites were formed through the co-assembly of an organic template and a precursor to form the desired mesostructured inorganic. For the case of the mesoporous silica spheres, a silica precursor was mixed with cetyltrimethylammonium bromide and cysteamine, a highly effective biomimetic catalyst for the conversion of alkoxysilanes to silica. Through charge-based interactions between anionic silica species and the micelle-forming cationic surfactant, ordered silica structures resulted. The incorporation of a novel, effective catalyst was found to form highly condensed silica spheres for potential application as catalyst supports or an encapsulation media. Ordered calcium phosphate-polymer composites were formed using two routes. Both routes take advantage of hydrogen bonding and ionic interactions between the calcium and phosphate precursors

  13. The chemical bond in inorganic chemistry the bond valence model

    CERN Document Server

    Brown, I David

    2016-01-01

    The bond valence model is a version of the ionic model in which the chemical constraints are expressed in terms of localized chemical bonds formed by the valence charge of the atoms. Theorems derived from the properties of the electrostatic flux predict the rules obeyed by both ionic and covalent bonds. They make quantitative predictions of coordination number, crystal structure, bond lengths and bond angles. Bond stability depends on the matching of the bonding strengths of the atoms, while the conflicting requirements of chemistry and space lead to the structural instabilities responsible for the unusual physical properties displayed by some materials. The model has applications in many fields ranging from mineralogy to molecular biology.

  14. Anatomical standardization of small animal brain FDG-PET images using synthetic functional template: experimental comparison with anatomical template.

    Science.gov (United States)

    Coello, Christopher; Hjornevik, Trine; Courivaud, Frédéric; Willoch, Frode

    2011-07-15

    Anatomical standardization (also called spatial normalization) of positron emission tomography (PET) small animal brain images is required to make statistical comparisons across individuals. Frequently, PET images are co-registered to an individual MR or CT image of the same subject in order to transform the functional images to an anatomical space. In the present work, we evaluate the normalization of synthetic PET (synPET) images to a synthetic PET template. To provide absolute error in terms of pixel misregistration, we created a synthetic PET image from the individual MR image through segmentation of the brain into gray and white matter which produced functional and anatomical images in the same space. When comparing spatial normalization of synPET images to a synPET template with the gold standard (MR images to an MR template), a mean translation error of 0.24mm (±0.20) and a maximal mean rotational error of 0.85° (±0.91) were found. Significant decrease in misregistration error was measured when achieving spatial normalization of functional images to a functional template instead of an anatomical template. This accuracy strengthens the use of standardization methods where individual PET images are registered to a customized PET template in order to statistically assess physiological changes in rat brains.

  15. Nanoparticle Array Assembly Using Chemical Templates

    Science.gov (United States)

    Adams, Sarah Marie

    This dissertation demonstrates chemically-driven self-assembly techniques to produce assemblies of closely-spaced metal nanoparticles from colloidal nanoparticle solution in order to engineer enhanced optical fields. Planar nanoparticle assemblies provide a platform for a multitude of applications and material architectures. With nanoscale inter-particle spacing, metallic nanoparticles enable increased efficiency of photovoltaic devices due to light focusing and enhancement of electromagnetic fields useful for optical sensing of molecules due to coupling of the plasmon resonance in nanoparticle gaps. For molecular sensors, development of self-assembled two-dimensional assemblies of closely-spaced nanoparticles is useful for producing surface plasmon resonance sensors and surface-enhanced Raman spectroscopy (SERS) based sensing. Using chemical self-assembly, monodisperse, colloidal gold nanoparticles were attached on self-organized polymer templates in order to pattern assemblies of nanoparticle clusters with sub-10 nanometer inter-particle spacing. First citrate-stabilized Au nanoparticles were functionalized with thioctic acid ligands in solution. Then poly(methyl methacrylate) domains in phase-separated poly(styrene-block-methyl methacrylate) (PS-b-PMMA) thin films were chemically modified with surface amine functional groups. Au nanoparticles were preferentially attached to the functionalized PMMA surface domains using cross-linking chemistry. This method allows for versatility of size, shape, and composition. In this dissertation, we demonstrated attachment of 5, 10, and 20 nm Au and 20 nm Ag nanoparticles. PS-b-PMMA thin films also exhibit versatility of domain size and morphology by varying polymer molecular weights. The nanoparticle diameter to PMMA domain size ratio influenced the cluster size. As the ratio decreased, larger clusters were observed on PMMA domains with increased frequency. SERS measurement of nanoparticle assemblies showed uniform signal

  16. Additional disulfide bonds in insulin

    DEFF Research Database (Denmark)

    Vinther, Tine N; Pettersson, Ingrid; Huus, Kasper

    2015-01-01

    -chain is flexible and can adapt multiple conformations. We examined how well disulfide bond predictions algorithms could identify disulfide bonds in this region of insulin. In order to identify stable insulin analogues with additional disulfide bonds, which could be expressed, the Cβ cut-off distance had...... in comparison to analogues with additional disulfide bonds that were more difficult to predict. In contrast, addition of the fourth disulfide bond rendered all analogues resistant to fibrillation under stress conditions and all stable analogues bound to the insulin receptor with picomolar affinities. Thus...

  17. Bond strength of direct and indirect bonded brackets after thermocycling.

    Science.gov (United States)

    Daub, Jacob; Berzins, David W; Linn, Brandon James; Bradley, Thomas Gerard

    2006-03-01

    Thermocycling simulates the temperature dynamics in the oral environment. With direct bonding, thermocycling reduces the bond strength of orthodontic adhesives to tooth structure. The purpose of this study was to evaluate the shear bond strengths (SBS) of one direct and two indirect bonding methods/adhesives after thermocycling. Sixty human premolars were divided into three groups. Teeth in group 1 were bonded directly with Transbond XT. Teeth in group 2 were indirect bonded with Transbond XT/Sondhi Rapid Set, which is chemically cured. Teeth in group 3 were indirect bonded with Enlight LV/Orthosolo and light cured. Each sample was thermocycled between 5 degrees C and 55 degrees C for 500 cycles. Mean SBS in groups 1, 2, and 3 were not statistically significantly different (13.6 +/- 2.9, 12.3 +/- 3.0, and 11.6 +/- 3.2 MPa, respectively; P > .05). However, when these values were compared with the results of a previous study using the same protocol, but without thermocycling, the SBS was reduced significantly (P = .001). Weibull analysis further showed that group 3 had the lowest bonding survival rate at the minimum clinically acceptable bond-strength range. The Adhesive Remnant Index was also determined, and group 2 had a significantly (P bond failures at the resin/enamel interface.

  18. Study of synthesis of nano-hydroxyapatite using a silk fibroin template

    Energy Technology Data Exchange (ETDEWEB)

    Wang Jing; Yu Feng; Qu Lijie; Meng Xiangcai [Provincial Key Laboratory of Biomaterials, Jiamusi University, Jiamusi 154007 (China); Wen, G [School of Materials Science and Engineering, Harbin Institute of Technology, Heilongjiang Province 150001 (China)

    2010-08-01

    Nano-hydroxyapatite (HA) was directly synthesized on a silk fibroin (SF) template using the property of SF being soluable in a concentrated CaCl{sub 2} solution as a HA source of calcium at pH 7.4 and room temperature. The microstructure and bonding state were investigated by x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry-thermogravimetry analysis (DSC-TG) and transmission electron microscopy (TEM). The results indicated that the HA crystals were poorly crystallized with a rod-like shape of 20-60 nm length and 10-20 nm diameter. Strong molecular interactions and chemical bonds might be present between SF and HA. There were other nucleation sites such as carbonyl (-C-O) and amine (-N-H-) groups on SF molecules besides the carboxyl (-COOH) and hydroxyl (-OH) groups previously reported. During the formation of HA, the coordination action between specific functional groups on SF and calcium ions (Ca{sup 2+}) played an important role. The crystallinity of HA was improved and had an orientation growth along (0 0 2) at the presence of SF, resulting in a structure similar to natural bone. It was concluded that SF could regulate the structure and morphology of HA effectively. (communication)

  19. The initial step of silicate versus aluminosilicate formation in zeolite synthesis: a reaction mechanism in water with a tetrapropylammonium template

    KAUST Repository

    Trinh, Thuat T.

    2012-01-01

    The initial step for silicate and aluminosilicate condensation is studied in water in the presence of a realistic tetrapropylammonium template under basic conditions. The model corresponds to the synthesis conditions of ZSM5. The free energy profile for the dimer formation ((OH) 3Si-O-Si-(OH) 2O - or [(OH) 3Al-O-Si-(OH) 3] -) is calculated with ab initio molecular dynamics and thermodynamic integration. The Si-O-Si dimer formation occurs in a two-step manner with an overall free energy barrier of 75 kJ mol -1. The first step is associated with the Si-O bond formation and results in an intermediate with a five-coordinated Si, and the second one concerns the removal of the water molecule. The template is displaced away from the Si centres upon dimer formation, and a shell of water molecules is inserted between the silicate and the template. The main effect of the template is to slow down the backward hydrolysis reaction with respect to the condensation one. The Al-O-Si dimer formation first requires the formation of a metastable precursor state by proton transfer from Si(OH) 4 to Al(OH) 4 - mediated by a solvent molecule. It then proceeds through a single step with an overall barrier of 70 kJ mol -1. The model with water molecules explicitly included is then compared to a simple calculation using an implicit continuum model for the solvent. The results underline the importance of an explicit and dynamical treatment of the water solvent, which plays a key role in assisting the reaction. © the Owner Societies 2012.

  20. DNA-templated nanowires as sacrificial materials for creating nanocapillaries

    Science.gov (United States)

    Stewart, Jacob T.; Becerril, Hector A.; Yang, Weichun; Larsen, Megan G.; Woolley, Adam T.

    2008-08-01

    DNA has shown great promise as a template for the controlled localization of various materials and the construction of wires with nanometer-dimension cross sections. We have recently developed a strategy for fabrication of nanocapillaries, using DNA-templated nanowires as a sacrificial material. We first form metal nanowires through the selective electrochemical deposition of nickel atop a surface-aligned DNA molecule. We then deposit a thin layer of silicon dioxide on top of the DNA nanostructures. Next, we photolithographically pattern openings over the ends of the wires and etch through the silicon dioxide layer to expose the metal nanowires. Finally, we etch out the DNA-templated nickel nanowires. This process results in the formation of nanocapillaries having the same dimensions as the originally formed DNA-templated nanowires. We have characterized these DNA-templated nanocapillaries using atomic force microscopy, optical microscopy and scanning electron microscopy. These constructs have potential for application in nanofluidics, power generation, sample preconcentration, and chemical sensing.

  1. Template identification technology of nuclear warheads and components

    Institute of Scientific and Technical Information of China (English)

    Liu Su-Ping; Gong Jian; Hao Fan-Hua; Hu Guang-Chun

    2008-01-01

    Template identification technology (TIT) is designed for the scenarios where a batch of disarmed nuclear weapons or components would be dismantled to observe a nuclear disarmament treaty.The core function played by the TIT is to make a judgment on whether the verified item belongs to a certain kind of nuclear weapons or component (NW/NC) or to which kind the verified item belongs.This paper analyses the functions played by the TIT in the process of NW/NC dismantlement,and proposes that two phases would be followed when applying the TIT:firstly to establish NW/NC templates with a sample of size n drawn from a certain kind of disarmament NW;secondly to authenticate NW/NC by means of the TIT.This paper also expatiates some terms related to the concept of the TIT and investigates on the development status of NW/NC TIT based on radiation signatures.The study concludes that the design of template structure is crucial to the establishment of an effective TIT and that starting from different research angles and aiming at the same goal of classification different template structures and corresponding template identification methods can be built up to meet specific identification requirements.

  2. Comparison of Bond in Roll-bonded and Adhesively Bonded Aluminums

    Science.gov (United States)

    Schwensfeir, R. J., Jr.; Trenkler, G.; Delagi, R. G.; Forster, J. A.

    1985-01-01

    Lap-shear and peel test measurements of bond strength have been carried out as part of an investigation of roll bonding of 2024 and 7075 aluminum alloys. Shear strengths of the bonded material in the F temper are in the range of 14 to 16 ksi. Corresponding peel strengths are 120 to 130 lb/inch. These values, which are three to five times those reported in the literature for adhesively bonded 2024 and 7075, are a result of the true metallurgical bond achieved. The effects of heat-treating the bonded material are described and the improvements in bond strength discussed relative to the shear strength of the parent material. The significance of the findings for aerospace applications is discussed.

  3. A Complex Network of Interactions between S282 and G283 of Hepatitis C Virus Nonstructural Protein 5B and the Template Strand Affects Susceptibility to Sofosbuvir and Ribavirin.

    Science.gov (United States)

    Kulkarni, Anupriya S; Damha, Masad J; Schinazi, Raymond F; Mo, Hongmei; Doehle, Brian; Sagan, Selena M; Götte, Matthias

    2016-04-01

    The hepatitis C virus (HCV) RNA-dependent RNA-polymerase NS5B is essentially required for viral replication and serves as a prominent drug target. Sofosbuvir is a prodrug of a nucleotide analog that interacts selectively with NS5B and has been approved for HCV treatment in combination with ribavirin. Although the emergence of resistance to sofosbuvir is rarely seen in the clinic, the S282T mutation was shown to decrease susceptibility to this drug. S282T was also shown to confer hypersusceptibility to ribavirin, which is of potential clinical benefit. Here we devised a biochemical approach to elucidate the underlying mechanisms. Recent crystallographic data revealed a hydrogen bond between S282 and the 2'-hydroxyl of the bound nucleotide, while the adjacent G283 forms a hydrogen bond with the 2'-hydroxyl of the residue of the template that base pairs with the nucleotide substrate. We show that DNA-like modifications of the template that disrupt hydrogen bonding with G283 cause enzyme pausing with natural nucleotides. However, the specifically introduced DNA residue of the template reestablishes binding and incorporation of sofosbuvir in the context of S282T. Moreover, the DNA-like modifications of the template prevent the incorporation of ribavirin in the context of the wild-type enzyme, whereas the S282T mutant enables the binding and incorporation of ribavirin under the same conditions. Together, these findings provide strong evidence to show that susceptibility to sofosbuvir and ribavirin depends crucially on a network of interdependent hydrogen bonds that involve the adjacent residues S282 and G283 and their interactions with the incoming nucleotide and complementary template residue, respectively.

  4. 27 CFR 28.66 - Strengthening bonds.

    Science.gov (United States)

    2010-04-01

    ... bonds. In all cases where the penal sum of any bond becomes insufficient, the principal shall either give a strengthening bond with the same surety to attain a sufficient penal sum, or give a new bond to... of any bond to less than its full penal sum. Strengthening bonds shall show the current date...

  5. Template free synthesis of natural carbohydrates functionalised fluorescent silver nanoclusters.

    Science.gov (United States)

    Ebrahiminezhad, Alireza; Berenjian, Aydin; Ghasemi, Younes

    2016-06-01

    Template-assisted synthesis is one of the most recognised techniques for fabrication of silver nanoclusters (AgNCs). However, this process is time consuming, toxic and expensive. In this study, the authors report a completely novel approach for the green and facile synthesis of AgNCs using Matricaria chamomilla, without any additional template. Fluorescent and colloidally stable AgNCs with average particle size of 2.4 nm were successfully produced. They found that carbohydrates from Matricaria chamomilla act as an ideal template to generate fluorescent AgNCs. Moreover, oxygen-bearing functional groups were validated to be the active groups for anchoring and reducing of Ag(+) ions. The novel carbohydrate coating method makes the prepared nanoclusters completely hydrophilic and stable in aqueous matrices.

  6. Geometrical assembly of ultrastable protein templates for nanomaterials

    Science.gov (United States)

    Glover, Dominic J.; Giger, Lars; Kim, Steve S.; Naik, Rajesh R.; Clark, Douglas S.

    2016-06-01

    The fabrication of nanoscale devices requires architectural templates on which to position functional molecules in complex arrangements. Protein scaffolds are particularly promising templates for nanomaterials due to inherent molecular recognition and self-assembly capabilities combined with genetically encoded functionalities. However, difficulties in engineering protein quaternary structure into stable and well-ordered shapes have hampered progress. Here we report the development of an ultrastable biomolecular construction kit for the assembly of filamentous proteins into geometrically defined templates of controllable size and symmetry. The strategy combines redesign of protein-protein interaction specificity with the creation of tunable connector proteins that govern the assembly and projection angles of the filaments. The functionality of these nanoarchitectures is illustrated by incorporation of nanoparticles at specific locations and orientations to create hybrid materials such as conductive nanowires. These new structural components facilitate the manufacturing of nanomaterials with diverse shapes and functional properties over a wide range of processing conditions.

  7. Template synthesis, characterization and transformations of iron nanowires while aging

    Energy Technology Data Exchange (ETDEWEB)

    Jagminas, Arunas [Institute of Chemistry, A. Gostauto 9, LT-01108 Vilnius (Lithuania)], E-mail: jagmin@ktl.mii.lt; Mazeika, Kestutis; Reklaitis, Jonas [Institute of Physics, Savanoriu 231, LT-02300 Vilnius (Lithuania); Kurtinaitiene, Marija [Institute of Chemistry, A. Gostauto 9, LT-01108 Vilnius (Lithuania); Baltrunas, Dalis [Institute of Physics, Savanoriu 231, LT-02300 Vilnius (Lithuania)

    2008-05-15

    Densely packed arrays of various materials demonstrating enhanced magnetic properties remain of great interest nowadays. In this study, transmission electron microscopy (TEM), Moessbauer spectroscopy (MS) and powder X-ray diffraction (XRD) were used to characterize the morphology, composition and phase of iron nanowires (nws) deposited from the developed solution within alumina template pores of the average diameter of ca.15 nm by the alternating current (ac) electrolysis protocol. The same investigations were performed after Fe nws storage in the air for several months. Characterization of the as-grown product shows the formation of the crystalline {alpha}-Fe nws array with a preferred [1 1 0] nw growth direction. The aging of samples leads to the corrosion of Fe nws mainly from the template top side while aging of Fe nws liberated from the template and kept for several months under ambient conditions results in the corrosion of nws along their full length producing catkin-twig shapes.

  8. Nanoline templates for single atom wires on Si(001)

    Energy Technology Data Exchange (ETDEWEB)

    Koester, Sigrun A.; Owen, James H.G.; Bianco, Francois; Mazur, Daniel; Renner, Chrisoph [Universite de Geneve, Section Physique/DPMC, Geneve (Switzerland); Rodriguez-Prieto, Alvaro; Bowler, David R. [London Centre for Nanotechnology (LCN), University College London (United Kingdom)

    2010-07-01

    Low dimensional structures are of wide scientific and technological interest. The physics of single atom metallic wires is already described in detail by theory, but a more systematic experimental verification is still desirable. The experimental problems are mainly caused by the difficulties of growing electronically isolated wires which is necessary to test the expected properties from existing theories. Here we introduce templates on a Si(001) surface which enable the growth of self-assembled single atom wires on top of them. The main template consists of a Si reconstruction called the Haiku structure which develops underneath self-assembled Bi nanowires. By hydrogenation the Si surface can be passivated and additionally the Bi dimers are stripped off while the underlying reconstruction of the Si surface remains intact. In addition the Bi nanowire by itself can be considered as a template.

  9. Implementation Support of Security Design Patterns Using Test Templates

    Directory of Open Access Journals (Sweden)

    Masatoshi Yoshizawa

    2016-06-01

    Full Text Available Security patterns are intended to support software developers as the patterns encapsulate security expert knowledge. However, these patterns may be inappropriately applied because most developers are not security experts, leading to threats and vulnerabilities. Here we propose a support method for security design patterns in the implementation phase of software development. Our method creates a test template from a security design pattern, consisting of an “aspect test template” to observe the internal processing and a “test case template”. Providing design information creates a test from the test template with a tool. Because our test template is reusable, it can easily perform a test to validate a security design pattern. In an experiment involving four students majoring in information sciences, we confirm that our method can realize an effective test, verify pattern applications, and support pattern implementation.

  10. Kinetic theory and thermodynamics of template-directed copolymerization

    Science.gov (United States)

    Gaspard, Pierre

    2017-02-01

    Template-directed copolymerization is the fundamental process for the replication, transcription, and translation of genetic information. The copy of the template sequence is grown by the attachment of monomers with a molecular machine. The long-time kinetics of such processes is exactly solvable in terms of iterated function systems. This method determines the effects of sequence heterogeneity and replication errors on the growth of the copy and the statistical properties of its sequence. In particular, a transition can occur between linear and sublinear growth in time of the copy. In the linear regime, the local growth velocity along the template may have a fractal distribution. Furthermore, the growth can be driven around equilibrium by the entropic effect of replication errors in an adverse free-energy landscape.

  11. Fabrication of YBCO nanowires with anodic aluminum oxide (AAO) template

    Energy Technology Data Exchange (ETDEWEB)

    Dadras, Sedigheh, E-mail: dadras@alzahra.ac.ir; Aawani, Elaheh

    2015-10-15

    We have fabricated YBCO nanowires by using anodic aluminum oxide (AAO) template and sol–gel method, to investigate the fundamental properties of the one-dimensional nanostructure YBCO high-temperature superconductor and enhance its applications. The field-emission scanning electron microscopy and X-ray diffraction pattern results have shown forming of Y-123 nanowires in the template. As an outcome, the YBCO nanowires, prepared by dipping AAO template into YBCO sol method, have average diameter of about 38 nm and length of 1 μm; this is an optimum nanowire sample with larger diameter and length. The resistance–temperature measurement indicates that the onset critical temperature of these samples occurs at 91 K, and the resistance of the optimum sample at onset transition is 10 times lower than the other sample.

  12. Template-Directed Biopolymerization: Tape-Copying Turing Machines

    Science.gov (United States)

    Sharma, Ajeet K.; Chowdhury, Debashish

    2012-10-01

    DNA, RNA and proteins are among the most important macromolecules in a living cell. These molecules are polymerized by molecular machines. These natural nano-machines polymerize such macromolecules, adding one monomer at a time, using another linear polymer as the corresponding template. The machine utilizes input chemical energy to move along the template which also serves as a track for the movements of the machine. In the Alan Turing year 2012, it is worth pointing out that these machines are "tape-copying Turing machines". We review the operational mechanisms of the polymerizer machines and their collective behavior from the perspective of statistical physics, emphasizing their common features in spite of the crucial differences in their biological functions. We also draw the attention of the physics community to another class of modular machines that carry out a different type of template-directed polymerization. We hope this review will inspire new kinetic models for these modular machines.

  13. A non-parametric 2D deformable template classifier

    DEFF Research Database (Denmark)

    Schultz, Nette; Nielsen, Allan Aasbjerg; Conradsen, Knut;

    2005-01-01

    We introduce an interactive segmentation method for a sea floor survey. The method is based on a deformable template classifier and is developed to segment data from an echo sounder post-processor called RoxAnn. RoxAnn collects two different measures for each observation point, and in this 2D...... feature space the ship-master will be able to interactively define a segmentation map, which is refined and optimized by the deformable template algorithms. The deformable templates are defined as two-dimensional vector-cycles. Local random transformations are applied to the vector-cycles, and stochastic...... relaxation in a Bayesian scheme is used. In the Bayesian likelihood a class density function and its estimate hereof is introduced, which is designed to separate the feature space. The method is verified on data collected in Øresund, Scandinavia. The data come from four geographically different areas. Two...

  14. Mesoporous silica and organosilica films templated by nanocrystalline chitin.

    Science.gov (United States)

    Nguyen, Thanh-Dinh; Shopsowitz, Kevin E; MacLachlan, Mark J

    2013-11-04

    Liquid crystalline phases can be used to impart order into inorganic solids, creating materials that mimic natural architectures. Herein, mesoporous silica and organosilica films with layered structures and high surface areas have been templated by nanocrystalline chitin. Aqueous suspensions of spindle-shaped chitin nanocrystals were prepared by sequential deacetylation and hydrolysis of chitin fibrils isolated from king crab shells. The nanocrystalline chitin self-assembles into a nematic liquid-crystalline phase that has been used to template silica and organosilica composites. Removal of the chitin template by either calcination or sulfuric-acid-catalyzed hydrolysis gave mesoporous silica and ethylene-bridged organosilica films. The large, crack-free mesoporous films have layered structures with features that originate from the nematic organization of the nanocrystalline chitin.

  15. Electroless Fabrication of Cobalt Alloys Nanowires within Alumina Template

    Directory of Open Access Journals (Sweden)

    Nazila Dadvand

    2007-01-01

    Full Text Available A new method of nanowire fabrication based on electroless deposition process is described. The method is novel compared to the current electroless procedure used in making nanowires as it involves growing nanowires from the bottom up. The length of the nanowires was controlled at will simply by adjusting the deposition time. The nanowires were fabricated within the nanopores of an alumina template. It was accomplished by coating one side of the template by a thin layer of palladium in order to activate the electroless deposition within the nanopores from bottom up. However, prior to electroless deposition process, the template was pretreated with a suitable wetting agent in order to facilitate the penetration of the plating solution through the pores. As well, the electroless deposition process combined with oblique metal evaporation process within a prestructured silicon wafer was used in order to fabricate long nanowires along one side of the grooves within the wafer.

  16. Templates for Cross-Cultural and Culturally Specific Usability Testing

    DEFF Research Database (Denmark)

    Clemmensen, Torkil

    2011-01-01

    The cultural diversity of users of technology challenges our methods for usability testing. This article suggests templates for cross-culturally and culturally specific usability testing, based on studies of usability testing in companies in Mumbai, Beijing, and Copenhagen. Study 1 was a cross...... tests. The result was the construction of templates for usability testing. The culturally specific templates were in Mumbai “user-centered evaluation,” Copenhagen “client-centered evaluation,” and Beijing “evaluator-centered evaluation.” The findings are compared with related research......-cultural field study of think-aloud testing done by usability vendor companies in the three countries. The result was a grounded theory of cultural variations in the production of a usability problem list. Study 2 was a follow-up, ethnographic interview study of how the companies typically perform usability...

  17. A geometric transformation to protect minutiae-based fingerprint templates

    Science.gov (United States)

    Sutcu, Yagiz; Sencar, Husrev T.; Memon, Nasir

    2007-04-01

    The increasing use of biometrics in different environments presents new challenges. Most importantly, biometric data are irreplaceable. Therefore, storing biometric templates, which is unique to individual user, entails significant security risks. In this paper, we propose a geometric transformation for securing the minutiae based fingerprint templates. The proposed scheme employs a robust one-way transformation that maps geometrical configuration of the minutiae points into a fixed-length code vector. This representation enables efficient alignment and reliable matching. Experiments are conducted by applying the proposed method on a synthetically generated minutiae point sets. Preliminary results show that the proposed scheme provides a simple and effective solution to the template security problem of the minutiae based fingerprint.

  18. Conducting Polymer Nanostructures: Template Synthesis and Applications in Energy Storage

    Directory of Open Access Journals (Sweden)

    Lijia Pan

    2010-07-01

    Full Text Available Conducting polymer nanostructures have received increasing attention in both fundamental research and various application fields in recent decades. Compared with bulk conducting polymers, conducting polymer nanostructures are expected to display improved performance in energy storage because of the unique properties arising from their nanoscaled size: high electrical conductivity, large surface area, short path lengths for the transport of ions, and high electrochemical activity. Template methods are emerging for a sort of facile, efficient, and highly controllable synthesis of conducting polymer nanostructures. This paper reviews template synthesis routes for conducting polymer nanostructures, including soft and hard template methods, as well as its mechanisms. The application of conducting polymer mesostructures in energy storage devices, such as supercapacitors and rechargeable batteries, are discussed.

  19. Conducting polymer nanostructures: template synthesis and applications in energy storage.

    Science.gov (United States)

    Pan, Lijia; Qiu, Hao; Dou, Chunmeng; Li, Yun; Pu, Lin; Xu, Jianbin; Shi, Yi

    2010-07-02

    Conducting polymer nanostructures have received increasing attention in both fundamental research and various application fields in recent decades. Compared with bulk conducting polymers, conducting polymer nanostructures are expected to display improved performance in energy storage because of the unique properties arising from their nanoscaled size: high electrical conductivity, large surface area, short path lengths for the transport of ions, and high electrochemical activity. Template methods are emerging for a sort of facile, efficient, and highly controllable synthesis of conducting polymer nanostructures. This paper reviews template synthesis routes for conducting polymer nanostructures, including soft and hard template methods, as well as its mechanisms. The application of conducting polymer mesostructures in energy storage devices, such as supercapacitors and rechargeable batteries, are discussed.

  20. 3D-printed guiding templates for improved osteosarcoma resection

    Science.gov (United States)

    Ma, Limin; Zhou, Ye; Zhu, Ye; Lin, Zefeng; Wang, Yingjun; Zhang, Yu; Xia, Hong; Mao, Chuanbin

    2016-03-01

    Osteosarcoma resection is challenging due to the variable location of tumors and their proximity with surrounding tissues. It also carries a high risk of postoperative complications. To overcome the challenge in precise osteosarcoma resection, computer-aided design (CAD) was used to design patient-specific guiding templates for osteosarcoma resection on the basis of the computer tomography (CT) scan and magnetic resonance imaging (MRI) of the osteosarcoma of human patients. Then 3D printing technique was used to fabricate the guiding templates. The guiding templates were used to guide the osteosarcoma surgery, leading to more precise resection of the tumorous bone and the implantation of the bone implants, less blood loss, shorter operation time and reduced radiation exposure during the operation. Follow-up studies show that the patients recovered well to reach a mean Musculoskeletal Tumor Society score of 27.125.