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Minkyung Kim, Sunae So, Kan Yao, Yongmin Liu, Junsuk Rho
Confining light into a sub-wavelength area has been challenging due to the natural phenomenon of diffraction. In this paper, we report deep sub-wavelength focusing via dispersion engineering based on hyperbolic metamaterials. Hyperbolic metamaterials, which can be realized by alternating layers of metal and dielectric, are materials showing opposite signs of effective permittivity along the radial and the tangential direction. They can be designed to exhibit a nearly-flat open isofrequency curve originated from the large-negative permittivity in the radial direction and small-positive one in the tangential direction...
December 7, 2016: Scientific Reports
Da Young Hwang, Dong Hack Suh
We report that a high local strain was obtained for multilayer MoS2 nanoscrolls decorated with noble nanoparticles (Ag and Au NPs) using a rolling process beyond breaking or slipping of MoS2. The local strain was estimated through the bending strain in the nanoscrolls and the extent of coverage of Ag and Au NPs decorated on MoS2, exhibiting magnified surface-enhanced Raman scattering. TEM images showed that the MoS2-Ag and MoS2-Au nanoscrolls have a tube-like morphology decorated with NPs on the inner and outer sides of the MoS2 nanoscrolls...
January 13, 2017: Nanotechnology
Marc Goetz, Anne Guivarc'h, Jörg Hirsche, Martin Andreas Bauerfeind, María-Cruz González, Tae Kyung Hyun, Seung Hee Eom, Dominique Chriqui, Thomas Engelke, Dominik K Großkinsky, Thomas Roitsch
Pollination in flowering plants is initiated by germination of pollen grains on stigmas followed by fast growth of pollen tubes representing highly energy-consuming processes. The symplastic isolation of pollen grains and tubes requires import of sucrose available in the apoplast. We show that the functional coupling of sucrose cleavage by invertases and uptake of the released hexoses by monosaccharide transporters are critical for pollination in tobacco. Transcript profiling, in situ hybridization and immunolocalization of extracellular invertases and two monosaccharide transporters in vitro and in vivo support the functional coupling in supplying carbohydrates for pollen germination and tube growth evidenced by spatiotemporally coordinated expression...
December 6, 2016: Plant Physiology
Martin Ledinský, Bertrand Paviet-Salomon, Aliaksei Vetushka, Jonas Geissbühler, Andrea Tomasi, Matthieu Despeisse, Stefaan De Wolf, Christophe Ballif, Antonín Fejfar
Thin, light-absorbing films attenuate the Raman signal of underlying substrates. In this article, we exploit this phenomenon to develop a contactless thickness profiling method for thin films deposited on rough substrates. We demonstrate this technique by probing profiles of thin amorphous silicon stripes deposited on rough crystalline silicon surfaces, which is a structure exploited in high-efficiency silicon heterojunction solar cells. Our spatially-resolved Raman measurements enable the thickness mapping of amorphous silicon over the whole active area of test solar cells with very high precision; the thickness detection limit is well below 1 nm and the spatial resolution is down to 500 nm, limited only by the optical resolution...
December 6, 2016: Scientific Reports
Zhili Wan, Yingen Sun, Lulu Ma, Jian Guo, Jinmei Wang, Shouwei Yin, Xiaoquan Yang
We report the novel use of the naturally occurring saponin, glycyrrhizic acid (GA) as a structuring material to transform liquid oil into a soft-solid structured emulsion system. The GA nanofibrils from the anisotropic self-assembly of GA molecules were first used as stabilizers to fabricate olive oil-in-water emulsions using a facile one-step emulsification at high temperature. Then, the obtained emulsions were further self-organized into the emulsion gel by applying a subsequent cooling to trigger the gel network formation, which is mostly due to the enhanced noncovalent interactions among GA fibrils in the continuous phase as well as at the droplet surface...
December 5, 2016: Food & Function
Marie A Hanebuth, Roman Kityk, Sandra J Fries, Alok Jain, Allison Kriel, Veronique Albanese, Tancred Frickey, Christine Peter, Matthias P Mayer, Judith Frydman, Elke Deuerling
Hsp70 chaperones assist de novo folding of newly synthesized proteins in all cells. In yeast, the specialized Hsp70 Ssb directly binds to ribosomes. The structural basis and functional mode of recruitment of Ssb to ribosomes is not understood. Here, we present the molecular details underlying ribosome binding of Ssb in Saccharomyces cerevisiae. This interaction is multifaceted, involving the co-chaperone RAC and two specific regions within Ssb characterized by positive charges. The C-terminus of Ssb mediates the key contact and a second attachment point is provided by a KRR-motif in the substrate binding domain...
December 5, 2016: Nature Communications
Guy Amah, Sebastian Voicu, Philippe Bonnin, Nathalie Kubis
PURPOSE: We investigated whether forearm skin blood flow could be improved when a multilayer pulsatile inflatable suit was applied at a low pressure to the lower limbs and abdomen. We hypothesized that a non-invasive purely mechanical stimulation of the lower limbs could induce remote forearm blood flow modifications. METHODS: The pulsatile suit induced a sequential compartmentalized low compression (65 mmHg), which was synchronized with each diastole of the cardiac cycle with each phase evolving centripetally (lower limbs to abdomen)...
December 1, 2016: Clinical and Investigative Medicine. Médecine Clinique et Experimentale
Valentina Cataldi, Emanuela Di Campli, Paolo Fazii, Tonino Traini, Luigina Cellini, Mara Di Giulio
Candida species are regular commensal in humans, but-especially in immunocompromised patients-they represent opportunistic pathogens giving rise to systemic infection. The aim of the present work was to isolate and characterize for their antifungal profile Candida species from different body sites and to analyze the biofilms produced by C. albicans and C. glabrata isolates. Eighty-one strains of Candida species from 77 patients were identified. Epidemiological study showed that the most isolated species were C...
December 2, 2016: Medical Mycology: Official Publication of the International Society for Human and Animal Mycology
Urszula Bazylińska, Renata Frąckowiak, Zbigniew Brzózka, Kazimiera A Wilk
Double-headed anionic surfactants could provide a profound group of efficient stabilizers of new template-mediated nanocarriers for effective encapsulation and sustained release of highly hydrophobic photosensitizers, and therefore their improved therapeutic activity in photodynamic therapy (PDT) protocols. We have thus encapsulated porphyrin-origin dyes, i.e., verteporfin (VP) and meso-tetraphenylporphyrin (TPP) in different types of sodium alkyliminobisacetates, Cn(COONa)2-stabilized nanosystems including biocompatible poly(l-glutamic acid)/poly(l-lysine) - PGA/PLL, multilayer nanocapsules (NCs)...
November 19, 2016: Journal of Photochemistry and Photobiology. B, Biology
Rami Haj-Ali, Eyass Massarwa, Jacob Aboudi, Fabio Galbusera, Uwe Wolfram, Hans-Joachim Wilke
A new three-dimensional (3D) multiscale micromechanical model has been suggested as adept at predicting the overall linear anisotropic mechanical properties of a vertebral trabecular bone (VTB) highly porous microstructure. A nested 3D modeling analysis framework spanning the multiscale nature of the VTB is presented herein. This hierarchical analysis framework employs the following micromechanical methods: the 3D parametric high-fidelity generalized method of cells (HFGMC) as well as the 3D sublaminate model...
December 2, 2016: Biomechanics and Modeling in Mechanobiology
Fernanda V Costa, Marco A R Mello, Judith L Bronstein, Tadeu J Guerra, Renata L Muylaert, Alice C Leite, Frederico S Neves
Ant-plant associations are an outstanding model to study the entangled ecological interactions that structure communities. However, most studies of plant-animal networks focus on only one type of resource that mediates these interactions (e.g, nectar or fruits), leading to a biased understanding of community structure. New approaches, however, have made possible to study several interaction types simultaneously through multilayer networks models. Here, we use this approach to ask whether the structural patterns described to date for ant-plant networks hold when multiple interactions with plant-derived food rewards are considered...
2016: PloS One
Xuepeng Qiu, William Legrand, Pan He, Yang Wu, Jiawei Yu, Rajagopalan Ramaswamy, Aurelien Manchon, Hyunsoo Yang
The magnitude of spin-orbit torque (SOT), exerted to a ferromagnet (FM) from an adjacent heavy metal (HM), strongly depends on the amount of spin current absorbed in the FM. We exploit the large spin absorption at the Ru interface to manipulate the SOTs in HM/FM/Ru multilayers. While the FM thickness is smaller than its spin dephasing length of 1.2 nm, the top Ru layer largely boosts the absorption of spin currents into the FM layer and substantially enhances the strength of SOT acting on the FM. Spin-pumping experiments induced by ferromagnetic resonance support our conclusions that the observed increase in the SOT efficiency can be attributed to an enhancement of the spin-current absorption...
November 18, 2016: Physical Review Letters
Robinjeet Singh, Garrett D Cole, Jonathan Cripe, Thomas Corbitt
We report a stable double optical spring effect in an optical cavity pumped with a single optical field that arises as a result of birefringence. One end of the cavity is formed by a multilayer Al_{0.92}Ga_{0.08}As/GaAs stack supported by a microfabricated cantilever with a natural mode frequency of 274 Hz. The optical spring shifts the resonance to 21 kHz, corresponding to a suppression of low frequency vibrations by a factor of about 5 000. The stable nature of the optical trap allows the cavity to be operated without any external feedback and with only a single optical field incident...
November 18, 2016: Physical Review Letters
L A Pickworth, J Ayers, P Bell, N F Brejnholt, J G Buscho, D Bradley, T Decker, S Hau-Riege, J Kilkenny, T McCarville, T Pardini, J Vogel, C Walton
Current two-dimensional X-ray imaging at the National Ignition Facility (NIF) uses time resolved pinhole cameras with ∼10-25 μm pinholes. This method has limitations in the smallest resolvable features that can be imaged with reasonable photon statistics for inertial confinement fusion (ICF) applications. ICF sources have a broadband self-emission spectrum that causes the pinhole images obtained, through thin foil filters, to contain a similarly broadband spectrum complicating the interpretation of structure in the source...
November 2016: Review of Scientific Instruments
Paolo Farace, Roberto Righetto, Sylvain Deffet, Arturs Meijers, Francois Vander Stappen
PURPOSE: To introduce a fast ray-tracing algorithm in pencil proton radiography (PR) with a multilayer ionization chamber (MLIC) for in vivo range error mapping. METHODS: Pencil beam PR was obtained by delivering spots uniformly positioned in a square (45 × 45 mm(2) field-of-view) of 9 × 9 spots capable of crossing the phantoms (210 MeV). The exit beam was collected by a MLIC to sample the integral depth dose (IDDMLIC). PRs of an electron-density and of a head phantom were acquired by moving the couch to obtain multiple 45 × 45 mm(2) frames...
December 2016: Medical Physics
Camila A Wilkens, Christopher J Rivet, Tamara L Akentjew, Julian Alverio, Maroun Khoury, Juan Pablo Acevedo
Successful tissue engineered small diameter blood vessels (SDBV) require manufacturing systems capable of precisely controlling different key elements, such as material composition, geometry and spatial location of specialized biomaterials and cells types. We report in this work an automated methodology that enables the manufacture of multilayer cylindrical constructs for SDBV fabrication that uses a layer-by-layer deposition approach while controlling variables such as dipping and spinning speed of a rod and biomaterial viscosity...
December 1, 2016: Biofabrication
J H Du, H Jin, Z K Zhang, D D Zhang, S Jia, L P Ma, W C Ren, H M Cheng, P L Burn
The large surface roughness, low work function and high cost of transparent electrodes using multilayer graphene films can limit their application in organic photovoltaic (OPV) cells. Here, we develop single layer graphene (SLG) films as transparent anodes for OPV cells that contain light-absorbing layers comprised of the evaporable molecular organic semiconductor materials, zinc phthalocyanine (ZnPc)/fullerene (C60), as well as a molybdenum oxide (MoOx) interfacial layer. In addition to an increase in the optical transmittance, the SLG anodes had a significant decrease in surface roughness compared to two and four layer graphene (TLG and FLG) anodes fabricated by multiple transfer and stacking of SLGs...
December 1, 2016: Nanoscale
Luca La Notte, Enrica Villari, Alessandro Lorenzo Palma, Alberto Sacchetti, Maria Michela Giangregorio, Giovanni Bruno, Aldo Di Carlo, Giuseppe Valerio Bianco, Andrea Reale
A five-layer (5L) graphene on a glass substrate has been demonstrated as a transparent conductive electrode to replace indium tin oxide (ITO) in organic photovoltaic devices. The required low sheet resistance, while maintaining high transparency, and the need of a wettable surface are the main issues. To overcome these, two strategies have been applied: (i) the p-doping of the multilayer graphene, thus reaching 25 Ω □(-1) or (ii) the O2-plasma oxidation of the last layer of the 5L graphene that results in a contact angle of 58° and a sheet resistance of 134 Ω □(-1)...
December 1, 2016: Nanoscale
Frédéric Dumur, Stéphane Reculusa, Michal Mruczkiewicz, Mathias Perrin, Laurence Vignau, Sophie Fasquel
Three-dimensional Langmuir-Blodgett films made of silica beads are theoretically and experimentally investigated in order to improve the relatively small efficiency of blue OLEDs. Using films made of 5 layers of beads, we fabricated OLEDs emitting at 476 nm, and measured a gain of around 40% on their external quantum efficiency. An optical model has been developed to accurately handle the fact that the organic emitting layer and the photonic extraction layer are separated by a distance greater than 1000 wavelength...
November 28, 2016: Optics Express
Mingwu Wen, Qiushi Huang, Shuang Ma, Wenbin Li, Rui She, Jichang Peng, Angelo Giglia, Igor V Kozhevnikov, Hua Feng, Zhong Zhang, Zhanshan Wang
Short-period (~3.5 nm) Co/C multilayer mirrors are fabricated by the direct current magnetron sputtering technique through the addition of a small proportion of nitrogen (4-15% partial pressure) to the working gas (Ar). The addition of nitrogen has been demonstrated to significantly suppress the interdiffusion of neighboring materials due to the nitridation of carbon layers as compared with the Co/C multilayer fabricated with the use of pure Ar. The optimal partial pressure of nitrogen was found to be 6%. At this pressure, nitrogen provides abrupt interfaces and the maximal peak value (19%) of the s-polarized radiation reflectivity at the 251-eV photon energy and 45° angle of incidence...
November 28, 2016: Optics Express
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