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Light trap

Paul A DeSario, Jeremy J Pietron, Adam Dunkelberger, Todd H Brintlinger, Olga Baturina, Rhonda M Stroud, Jeffrey C Owrutsky, Debra R Rolison
We use plasmonic Au-TiO2 aerogels as a platform in which to marry synthetically thickened particle-particle junctions in TiO2 aerogel networks and Au||TiO2 interfaces and then investigate their cooperative influence on photocatalytic hydrogen (H2) generation under both broadband (i.e., UV + visible light) and visible-only excitation. In doing so, we elucidate the dual functions that incorporated Au can play as a water reduction/H2 generation co-catalyst and as a plasmonic sensitizer. We also introduce non-plasmonic Pt co-catalyst nanoparticles into our composite aerogels in order to leverage the catalytic water-reducing abilities of Pt...
July 19, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Prabhu P Mohapatra, Callistus O Chiemezie, Arina Kligman, Michele M Kim, Theresa M Busch, Timothy C Zhu, Alexander Greer
Intralipid is a lipid emulsion used in photodynamic therapy (PDT) for its light scattering and tissue-simulating properties. The purpose of this study is to determine whether or not Intralipid undergoes photooxidation, we have carried out an Intralipid peroxide trapping study using a series of phosphines [2'-dicyclohexylphosphino-2,6-dimethoxy-1,1'-biphenyl-3-sulfonate, 3-(diphenylphosphino)benzenesulfonate, triphenylphosphine-3,3',3''-trisulfonate, and triphenylphosphine]. Our new findings are as follows: (i) An oxygen atom is transferred from Intralipid peroxide to the phosphine traps in the dark, after the photooxidation of Intralipid...
July 19, 2017: Photochemistry and Photobiology
Mengdi Chen, Danja Fischli, Lukas Schertel, Geoffroy J Aubry, Benedikt Häusele, Sebastian Polarz, Georg Maret, Helmut Cölfen
One efficient method to obtain disordered colloidal packing is to reduce the stability of colloidal particles by adding electrolytes to the colloidal dispersions. But the correct amount of additional electrolytes must be found empirically. Here, the effect of CaCl2 on polystyrene colloidal dispersions is studied, and a link between the amount of CaCl2 and the corresponding glassy colloidal structure is quantitatively built. A threshold concentration of CaCl2 is found by dynamic light scattering. When exceeding this threshold, different nanoparticle oligomers are observed in the dispersions by analytical ultracentrifugation...
July 19, 2017: Small
R G Mafia, E B Loureiro, J B Silva, J A C Simões, T G Zarpelon, N S Bezerra Junior, M B Damacena
Eucalyptus plantations can be affected by species of defoliating caterpillars. The integrated management of this group primarily involves a monitoring system, natural enemies, and biological products. Alternative control methods, including the use of conventional light traps, have not been adopted, mostly because of their low efficiency. Therefore, a more efficient light trap model was developed. The new model allowed the capture of 3.6 times as many insects as the conventional model, with a 261% gain in control efficiency...
July 18, 2017: Neotropical Entomology
R Jayaprakash, F G Kalaitzakis, G Christmann, K Tsagaraki, M Hocevar, B Gayral, E Monroy, N T Pelekanos
Polariton lasers are coherent light sources based on the condensation of exciton-polaritons in semiconductor microcavities, which occurs either in the kinetic or thermodynamic (Bose-Einstein) regime. Besides their fundamental interest, polariton lasers have the potential of extremely low operating thresholds. Here, we demonstrate ultra-low threshold polariton lasing at room temperature, using an all-dielectric, GaN membrane-based microcavity, with a spontaneously-formed zero-dimensional trap. The microcavity is fabricated using an innovative method, which involves photo-electrochemical etching of an InGaN sacrificial layer and allows for the incorporation of optimally-grown GaN active quantum wells inside a cavity with atomically-smooth surfaces...
July 17, 2017: Scientific Reports
Serhiy Kondratenko, Sviatoslav Iliash, Yuriy I Mazur, Vasyl P Kunets, Mourad Benamara, Gregory J Salamo
The time dependencies of the carrier relaxation in the modulation-doped InGaAs-GaAs low-dimensional structures with quantum wires have been studied as function of temperature and light excitation levels. The photoconductivity relaxation follows a stretched exponent with decay constant, which depends on morphology of InGaAs epitaxial layers, presence of deep traps and on energy disorder due to inhomogeneous distribution of size and composition. A hopping model, where electrons tunnel between bands of localized states, gives appropriate interpretation for temperature-independent PC decay across the temperature range 150-290 K...
July 17, 2017: Nanotechnology
Gonzalo Ramírez-García, Minerva Martínez-Alfaro, Fanny d'Orlyé, Fethi Bedioui, Nathalie Mignet, Anne Varenne, Silvia Gutiérrez-Granados, Cyrille Richard
Persistent luminescence nanoparticles made of ZnGa1.995Cr0.005O4 (ZGO-NPs) are innovative nanomaterials that emit photons during long periods of time after the end of the excitation, allowing their use as diagnosis probes for in vivo optical imaging. During the excitation process, a part of the energy is stored in traps to further emit photons over long time. However, we observed in this study that some of the energy reduces molecular oxygen to produce reactive oxygen species (ROS). Following this observation, theoxidative stress induction and cytotoxic effects of these NPs were investigated on human breast cancer cells...
July 13, 2017: International Journal of Pharmaceutics
Solomon Yared, Araya Gebreselassie, Essayas Akililu, Kebede Deribe, Meshesha Balkew, Alon Warburg, Asrat Hailu, Teshome Gebre-Michael
BACKGROUND: The Leishmaniases are caused by the protozoan parasites of the genus Leishmania and are transmitted to humans by the bite of infected female phlebotomine sand flies. Both visceral and cutaneous leishmaniases are widely distributed in different parts of Ethiopia. The aim of this study was to determine the diversity and altitudinal distribution of phlebotomine sand flies from Kafta Humera to Gondar town in northwest Ethiopia. METHODS: Seven localities were selected with distinct altitudinal variations between 550m above sea level (m a...
July 13, 2017: Acta Tropica
Hiroaki Hirakawa, Masaki Hashimoto, Yasuhiro Shiraishi, Takayuki Hirai
Ammonia (NH3) is an essential chemical in modern society. It is currently manufactured by the Haber-Bosch process using H2 and N2 under extremely high pressure (>200 bar) and high temperature (>673 K) conditions. Photocatalytic NH3 production from water and N2 at atmospheric pressure and room temperature is ideal. Several semiconductor photocatalysts have been proposed, but all suffer from low efficiency. Here we report that a commercially-available TiO2 with a large number of surface oxygen vacancies, when photoirradiated by UV light in pure water with N2, successfully produces NH3...
July 17, 2017: Journal of the American Chemical Society
K A Gilmore, J G Bohnet, B C Sawyer, J W Britton, J J Bollinger
We present a technique to measure the amplitude of a center-of-mass (c.m.) motion of a two-dimensional ion crystal of ∼100 ions. By sensing motion at frequencies far from the c.m. resonance frequency, we experimentally determine the technique's measurement imprecision. We resolve amplitudes as small as 50 pm, 40 times smaller than the c.m. mode zero-point fluctuations. The technique employs a spin-dependent, optical-dipole force to couple the mechanical oscillation to the electron spins of the trapped ions, enabling a measurement of one quadrature of the c...
June 30, 2017: Physical Review Letters
Mina Mirsafaei, Amir Hossein Fallahpour, Paolo Lugli, Horst-Günter Rubahn, Jost Adam, Morten Madsen
Integration of light-trapping features and exploitation of metal nanostructure plasmonic effects are promising approaches for enhancing the power conversion efficiency of organic solar cells. These approaches' effects on the light absorption enhancement have been widely studied, especially in inorganic devices. While this light-trapping concept can be transferred to organic devices, one has to also consider nanostructure-induced electrical effects on the device performance, due to the fundamental difference in the organic semiconducting material properties compared to their inorganic counterparts...
July 13, 2017: Scientific Reports
Gabriella Gaglio, Ettore Napoli, Luigi Falsone, Salvatore Giannetto, Emanuele Brianti
Light traps are one of the most common attractive method for the collection of nocturnal insects. Although light traps are generally referred to as "CDC light traps", different models, equipped with incandescent or UV lamps, have been developed. A new light trap, named Laika trap 3.0, equipped with LED lamps and featured with a light and handy design, has been recently proposed into the market. In this study we tested and compared the capture performances of this new trap with those of a classical light trap model under field conditions...
July 11, 2017: Acta Tropica
Benjamin L Greenberg, Zachary L Robinson, Konstantin V Reich, Claudia Gorynski, Bryan N Voigt, Lorraine F Francis, Boris I Shklovskii, Eray S Aydil, Uwe R Kortshagen
Networks of ligand-free semiconductor nanocrystals (NCs) offer a valuable combination of high carrier mobility and optoelectronic properties tunable via quantum confinement. In principle, maximizing carrier mobility entails crossing the insulator-metal transition (IMT), where carriers become delocalized. A recent theoretical study predicted that this transition occurs at nρ(3) ≈ 0.3, where n is the carrier density and ρ is the interparticle contact radius. In this work, we satisfy this criterion in networks of plasma-synthesized ZnO NCs by using intense pulsed light (IPL) annealing to tune n and ρ independently...
July 13, 2017: Nano Letters
Ronildo Baiatone Alencar, José Ferreira Saraiva, Arley Faria José de Oliveira, Vera Margarete Scarpassa
INTRODUCTION: The muscoid fly Dermatobia hominis causes cutaneous myiases in mammals. Females of this species use a vector to carry their eggs to the host. This note describes Anopheles konderi acting as phoretic vector for D. hominis. METHODS: A female A. konderi carrying D. hominis was collected using light traps in Oriximiná, Pará, Brazil. The A. konderi specimen was identified at morphological and molecular levels. RESULTS: Eight eggs of D...
May 2017: Revista da Sociedade Brasileira de Medicina Tropical
Qiaochu Li, Stephen J King, Jing Xu
Molecular motors such as kinesin-1 work in small teams to actively shuttle cargos in cells, for example in polarized transport in axons. Here we examined the potential regulatory role of the nucleotide state of tubulin on the run length of cargos carried by multiple kinesin motors, using an optical trapping-based in vitro assay. Based on a previous report that kinesin binds preferentially to GTP-tubulin-rich microtubules, we anticipated that multiple-kinesin cargos would run substantially greater distances along GMPCPP microtubules than along GDP microtubules...
July 12, 2017: Cytoskeleton
A Miniewicz, C Quintard, H Orlikowska, S Bartkiewicz
Gas bubbles can be trapped and then manipulated with laser light. In this report, we propose the detailed optical trapping mechanism of gas bubbles confined inside a thin light-absorbing liquid layer between two glass plates. The necessary condition of bubble trapping in this case is the direct absorption of light by the solution containing a dye. Due to heat release, fluid whirls propelled by the surface Marangoni effect at the liquid/gas interface emerge and extend to large distances. We report the experimental microscopic observation of the origin of whirls at an initially flat liquid/air interface as well as at the curved interface of a liquid/gas bubble and support this finding with advanced numerical simulations using the finite element method within the COMSOL Multiphysics platform...
July 11, 2017: Physical Chemistry Chemical Physics: PCCP
Navadeep Shrivastava, L U Khan, J M Vargas, Carlos Ospina, J A Q Coaquira, Giorgio Zoppellaro, H F Brito, Yasir Javed, D K Shukla, M C F C Felinto, Surender K Sharma
Luminescence-tunable multicolored LaF3:xCe(3+),xGd(3+),yEu(3+) (x = 5; y = 1, 5, 10, and 15 mol%) nanoparticles have been synthesized via a low cost polyol method. Powder X-ray diffraction and high-resolution transmission electron microscopy studies confirm the hexagonal phase of the LaF3:xCe(3+),xGd(3+),yEu(3+) nanophosphors with average sizes (oval shape) ranging from 5 to 7 nm. Energy-dispersive X-ray spectroscopy analyses show the uniform distribution of Ce(3+), Gd(3+), and Eu(3+) dopants in the LaF3 host matrix...
July 11, 2017: Physical Chemistry Chemical Physics: PCCP
Haizhu Sun, Zhenyu Yang, Mingyang Wei, Wei Sun, Xiyan Li, Shuyang Ye, Yongbiao Zhao, Hairen Tan, Emily L Kynaston, Tyler B Schon, Han Yan, Zheng-Hong Lu, Geoffrey A Ozin, Edward H Sargent, Dwight S Seferos
Whereas organic-inorganic hybrid perovskite nanocrystals (PNCs) have remarkable potential in the development of optoelectronic materials, their relatively poor chemical and colloidal stability undermines their performance in optoelectronic devices. Herein, this issue is addressed by passivating PNCs with a class of chemically addressable ligands. The robust ligands effectively protect the PNC surfaces, enhance PNC solution processability, and can be chemically addressed by thermally induced crosslinking or radical-induced polymerization...
July 10, 2017: Advanced Materials
Lijian Zuo, Jiangsheng Yu, Xueliang Shi, Francis Lin, Weihua Tang, Alex K-Y Jen
In this work, a highly efficient parallel connected tandem solar cell utilizing a nonfullerene acceptor is demonstrated. Guided by optical simulation, each of the active layer thicknesses of subcells are tuned to maximize its light trapping without spending intense effort to match photocurrent. Interestingly, a strong optical microcavity with dual oscillation centers is formed in a back subcell, which further enhances light absorption. The parallel tandem device shows an improved photon-to-electron response over the range between 450 and 800 nm, and a high short-circuit current density (J SC ) of 17...
July 10, 2017: Advanced Materials
Danqing Wang, Ankun Yang, Weijia Wang, Yi Hua, Richard D Schaller, George C Schatz, Teri W Odom
Single band-edge states can trap light and function as high-quality optical feedback for microscale lasers and nanolasers. However, access to more than a single band-edge mode for nanolasing has not been possible because of limited cavity designs. Here, we describe how plasmonic superlattices-finite-arrays of nanoparticles (patches) grouped into microscale arrays-can support multiple band-edge modes capable of multi-modal nanolasing at programmed emission wavelengths and with large mode spacings. Different lasing modes show distinct input-output light behaviour and decay dynamics that can be tailored by nanoparticle size...
July 10, 2017: Nature Nanotechnology
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