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Optical control

Mette Funding la Cour, Shima Mehrvar, James S Heisner, Mohammad Masoudi Motlagh, Meetha Medhora, Mahsa Ranji, Amadou K S Camara
Whole thoracic irradiation (WTI) is known to cause deterioration in cardiac function. Whether irradiation predisposes the heart to further ischemia and reperfusion (IR) injury is not well known. The aim of this study is to examine the susceptibility of rat hearts to IR injury following a single fraction of 15 Gy WTI and to investigate the role of mitochondrial metabolism in the differential susceptibility to IR injury. After day 35 of irradiation, ex vivo hearts from irradiated and nonirradiated rats (controls) were exposed to 25-min global ischemia followed by 60-min IR, or hearts were perfused without IR for the same protocol duration [time controls (TC)]...
January 2018: Journal of Biomedical Optics
Vyacheslav Timofeev, Alexandr Nikiforov, Artur Tuktamyshev, Vladimir Mashanov, Michail Yesin, Aleksey Bloshkin
The dependences of the two-dimensional to three-dimensional growth (2D-3D) critical transition thickness on the composition for GeSiSn films with a fixed Ge content and Sn content from 0 to 16% at the growth temperature of 150 °С have been obtained. The phase diagrams of the superstructure change during the epitaxial growth of Sn on Si and on Ge(100) have been built. Using the phase diagram data, it becomes possible to identify the Sn cover on the Si surface and to control the Sn segregation on the superstructure observed on the reflection high-energy electron diffraction (RHEED) pattern...
January 19, 2018: Nanoscale Research Letters
Hiroki Gonome, Masashi Nakamura, Junnosuke Okajima, Shigenao Maruyama
Chameleons have a diagnostic thermal protection that enables them to live under various conditions. Our developed special radiative control therefore is inspired by the chameleon thermal protection ability by imitating its two superposed layers as two pigment particles in one coating layer. One particle imitates a chameleon superficial surface for color control (visible light), and another particle imitates a deep surface to reflect solar irradiation, especially in the near-infrared region. Optical modeling allows us to optimally design the particle size and volume fraction...
January 19, 2018: Scientific Reports
Yunlong Wang, Cuifeng Ying, Wenyuan Zhou, Lennart de Vreede, Zhibo Liu, Jianguo Tian
This paper reports a controlled breakdown (CBD) method to fabricate multiple nanopores in a silicon nitride (SiNx) membrane with control over both nanopore count and nanopore diameter. Despite the stochastic process of the breakdown, we found that the nanopores created via CBD, tend to be of the same diameter. We propose a membrane resistance model to explain and control the multiple nanopores forming in the membrane. We prove that the membrane resistance can reflect the number of nanopores in the membrane and that the diameter of the nanopores is controlled by the exposure time and strength of the electric field...
January 19, 2018: Scientific Reports
Arvind P Ravikumar, Jingfan Wang, Mike McGuire, Clay S Bell, Daniel Zimmerle, Adam R Brandt
Methane - a key component of natural gas - is a potent greenhouse gas. A key feature of recent methane mitigation policies is the use of periodic leak detection surveys, typically done with optical gas imaging (OGI) technologies. The most common OGI technology is an infrared camera. In this work, we experimentally develop detection probability curves for OGI-based methane leak detection under different environmental and imaging conditions. Controlled single blind leak detection tests show that the median detection limit (50% detection likelihood) for FLIR-camera based OGI technology is about 20 g CH4/h at an imaging distance of 6 m, an order of magnitude higher than previously reported estimates of 1...
January 19, 2018: Environmental Science & Technology
Anthony C Johnson, Rocco Latorre, Casey O Ligon, Beverley Greenwood-Van Meerveld
In vivo optogenetics identifies brain circuits controlling behaviors in conscious animals by using light to alter neuronal function and offers a novel tool to study the brain-gut axis. Using adenoviral-mediated expression, we aimed to investigate whether photoactivation with channelrhodopsin (ChR2) or photoinhibition with halorhodopsin (HR3.0) of fibers originating from the central nucleus of the amygdala (CeA) at the bed nucleus of the stria terminalis (BNST) had any effect on colonic sensitivity. We also investigated whether that there was any deleterious effect of the adenovirus on the neuronal population or the neuronal phenotype within the CeA-BNST circuitry activated during the optogenetic stimulation...
December 14, 2017: American Journal of Physiology. Gastrointestinal and Liver Physiology
Chiao-Yu Cheng, Rijul Dhanker, Christopher L Gray, Sukrit Mukhopadhyay, Eric R Kennehan, John B Asbury, Anatoliy Sokolov, Noel C Giebink
We report strong coupling between light and polaron optical excitations in a doped organic semiconductor microcavity at room temperature. Codepositing MoO_{3} and the hole transport material 4, 4^{'}-cyclohexylidenebis[N, N-bis(4-methylphenyl)benzenamine] introduces a large hole density with a narrow linewidth optical transition centered at 1.8 eV and an absorption coefficient exceeding 10^{4}  cm^{-1}. Coupling this transition to a Fabry-Pérot cavity mode yields upper and lower polaron polariton branches that are clearly resolved in angle-dependent reflectivity with a vacuum Rabi splitting ℏΩ_{R}>0...
January 5, 2018: Physical Review Letters
Gun-Yeal Lee, Gwanho Yoon, Seung-Yeol Lee, Hansik Yun, Jaebum Cho, Kyookeun Lee, Hwi Kim, Junsuk Rho, Byoungho Lee
Reconstruction of light profiles with amplitude and phase information, called holography, is an attractive optical technology with various significant applications such as three-dimensional imaging and optical data storage. Subwavelength spatial control of both amplitude and phase of light is an essential requirement for an ideal hologram. However, traditional holographic devices suffer from their restricted capabilities of incomplete modulation in both amplitude and phase of visible light; this results in sacrifice of optical information and undesirable occurrences of critical noises in holographic images...
January 19, 2018: Nanoscale
Gang Wang, Qinglei Guo, Da Chen, Zhiduo Liu, Xiaohu Zheng, Anli Xu, Siwei Yang, Guqiao Ding
Recently, the biomass "bottom-up" approach for the synthesis of graphene quantum dots have attracted broad interest because of the outstanding features, including low-cost, rapid and environmentally friendly nature. However, the low crystalline quality of products, substitutional doping with heteroatoms in lattice and ambiguous reaction mechanism strongly challenge the further development of this technique. Herein, we proposed a facile and effective strategy to prepare controllable sulfur (S) doping in graphene quantum dots, occurring in a lattice substitution manner, by hydrothermal treatment of durian with platinum catalyst...
January 19, 2018: ACS Applied Materials & Interfaces
Simon Pierce, Alberto Spada, Elisabetta Caporali, Roberta M Ceriani, Gabriella Buffa
The seed coat of many species contains hydrophobic lignins, and in soil the action of microbial ligninases may contribute to release from dormancy. Laboratory use of ligninases to stimulate germination is promising because of the specific action on the seed coat, whereas chemical scarification agents may also corrode the embryo. We hypothesized that exposure of Anacamptis morio (Orchidaceae) seeds to fungal laccase stimulates germination, and that the mechanism involves lignin degradation and increased imbibition...
January 19, 2018: Plant Biology
P Cortelletti, A Skripka, C Facciotti, M Pedroni, G Caputo, N Pinna, M Quintanilla, A Benayas, F Vetrone, A Speghini
Lanthanide-activated SrF2 nanoparticles with a multishell architecture were investigated as optical thermometers in the biological windows. A ratiometric approach based on the relative changes in the intensities of different lanthanide (Nd3+ and Yb3+) NIR emissions was applied to investigate the thermometric properties of the nanoparticles. It was found that an appropriate doping with Er3+ ions can increase the thermometric properties of the Nd3+-Yb3+ coupled systems. In addition, a core containing Yb3+ and Tm3+ can generate light in the visible and UV regions upon near-infrared (NIR) laser excitation at 980 nm...
January 19, 2018: Nanoscale
Metin Unlu, Duygu Gulmez Sevim, Murat Gultekin, Cagatay Karaca
To assess the correlation between functional and anatomical evaluations with multifocal electroretinography (mfERG) and spectral-domain optical coherence tomography (SD-OCT) in patients with Parkinson's disease (PD). This cross-sectional study involved 116 eyes of 58 patients with PD and 30 age- and sex-matched control subjects. All study participants underwent a comprehensive neuro-ophthalmic examination, retinal single-layer thicknesses and volumes, and peripapillary retinal nerve fiber layer (pRNFL) measurements with SD-OCT, and the patients' mfERG recordings were evaluated...
January 18, 2018: Neurological Sciences
Ran Finkelstein, Eilon Poem, Ohad Michel, Ohr Lahad, Ofer Firstenberg
Future quantum photonic networks require coherent optical memories for synchronizing quantum sources and gates of probabilistic nature. We demonstrate a fast ladder memory (FLAME) mapping the optical field onto the superposition between electronic orbitals of rubidium vapor. Using a ladder-level system of orbital transitions with nearly degenerate frequencies simultaneously enables high bandwidth, low noise, and long memory lifetime. We store and retrieve 1.7-ns-long pulses, containing 0.5 photons on average, and observe short-time external efficiency of 25%, memory lifetime (1/e) of 86 ns, and below 10-4 added noise photons...
January 2018: Science Advances
Lin Chen, Xianmin Ke, Huijie Guo, Junhao Li, Xun Li, Lei Zhou
Although metamaterials wave-plates have been demonstrated previously, many of them suffer from the issue of narrow bandwidth since they typically rely on resonance principles and thus exhibit inevitable frequency dispersions. Here, we show that the dispersion of spoof surface plasmon (SSP) mode supported by a fishbone structure can be freely modulated by varying the structural parameters. This motivates us to establish a general strategy of building broadband wave-plates by cascading two fishbone structures with different propagation constants of SSP modes...
January 18, 2018: Scientific Reports
Qing-Yuan Lin, Jarad A Mason, Zhongyang Li, Wenjie Zhou, Matthew N O'Brien, Keith A Brown, Matthew R Jones, Serkan Butun, Byeongdu Lee, Vinayak P Dravid, Koray Aydin, Chad A Mirkin
DNA programmable assembly has been combined with top-down lithography to construct superlattices of discrete, reconfigurable nanoparticle architectures on a gold surface over large areas. Specifically, the assembly of individual colloidal plasmonic nanoparticles with different shapes and sizes is controlled by oligonucleotides containing "locked" nucleic acids and confined environments provided by polymer pores to yield oriented architectures that feature tunable arrangements and independently controllable distances at both nanometer and micrometer length scales...
January 18, 2018: Science
Jihyeon Yeom, Uallisson S Santos, Mahshid Chekini, Minjeong Cha, André F de Moura, Nicholas A Kotov
Chiral inorganic nanostructures have high circular dichroism, but real-time control of their optical activity has so far been achieved only by irreversible chemical changes. Field modulation is a far more desirable path to chiroptical devices. We hypothesized that magnetic field modulation can be attained for chiral nanostructures with large contributions of the magnetic transition dipole moments to polarization rotation. We found that dispersions and gels of paramagnetic Co3O4 nanoparticles with chiral distortions of the crystal lattices exhibited chiroptical activity in the visible range that was 10 times as strong as that of nonparamagnetic nanoparticles of comparable size...
January 19, 2018: Science
Felipe Olivares, Luciano Zunino, Damián Gulich, Darío G Pérez, Osvaldo A Rosso
We have experimentally quantified the temporal structural diversity from the coordinate fluctuations of a laser beam propagating through isotropic optical turbulence. The main focus here is on the characterization of the long-range correlations in the wandering of a thin Gaussian laser beam over a screen after propagating through a turbulent medium. To fulfill this goal, a laboratory-controlled experiment was conducted in which coordinate fluctuations of the laser beam were recorded at a sufficiently high sampling rate for a wide range of turbulent conditions...
October 2017: Physical Review. E
Wenjun Liu, Chunyu Yang, Mengli Liu, Weitian Yu, Yujia Zhang, Ming Lei
The interactions of multiple solitons show different properties with two-soliton interactions. For the difficulty of deriving multiple soliton solutions, it is rare to study multiple soliton interactions analytically. In this paper, three-soliton interactions in inhomogeneous optical fibers, which are described by the variable coefficient Hirota equation, are investigated. Via the Hirota bilinear method and symbolic computation, analytic three-soliton solutions are obtained. According to the obtained solutions, properties and features of three-soliton interactions are discussed by changing the third-order dispersion (TOD) and other relevant coefficients, and some plentiful structure of three-soliton interactions are presented for the first time...
October 2017: Physical Review. E
Meital Harel, Haim Taitelbaum
The temperature effect on the dynamics and geometry of a mercury droplet (∼150 μm) spreading on a silver substrate (4000 Å) was studied. The system temperature was controlled by a heating stage in the temperature range of -15 °C < T < 25 °C, and the spreading process was monitored using an optical microscope. We studied the wetting dynamics (droplet radius and velocity) as a function of temperature. We found that for all studied temperatures, the spreading radius R(t) grows linearly with time, with a velocity value depending on temperature...
December 2017: Physical Review. E
N Lo Gullo, C V Ambarish, Th Busch, L Dell'Anna, C M Chandrashekar
We investigate the role of different aperiodic sequences in the dynamics of single quantum particles in discrete space and time. For this we consider three aperiodic sequences, namely, the Fibonacci, Thue-Morse, and Rudin-Shapiro sequences, as examples of tilings the diffraction spectra of which have pure point, singular continuous, and absolutely continuous support, respectively. Our interest is to understand how the order, intrinsically introduced by the deterministic rule used to generate the aperiodic sequences, is reflected in the dynamical properties of the quantum system...
July 2017: Physical Review. E
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