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double probe light

Zorawar Wadiasingh, Alice K Harding, Christo Venter, Markus Böttcher, Matthew G Baring
Multiwavelength followup of unidentified Fermi sources has vastly expanded the number of known galactic-field "black widow" and "redback" millisecond pulsar binaries. Focusing on their rotation-powered state, we interpret the radio to X-ray phenomenology in a consistent framework. We advocate the existence of two distinct modes differing in their intrabinary shock orientation, distinguished by the phase-centering of the double-peaked X-ray orbital modulation originating from mildly-relativistic Doppler boosting...
April 20, 2017: Astrophysical Journal
O Mitrofanov, Y Todorov, D Gacemi, A Mottaghizadeh, C Sirtori, I Brener, J L Reno
Highly confined modes in THz plasmonic resonators comprising two metallic elements can enhance light-matter interaction for efficient THz optoelectronic devices. We demonstrate that sub-surface modes in such double-metal resonators can be revealed with an aperture-type near-field probe and THz time-domain spectroscopy despite strong mode confinement in the dielectric spacer. The sub-surface modes couple a fraction of their energy to the resonator surface via surface waves, which we detected with the near-field probe...
March 19, 2018: Optics Express
Tanu Parmar, Vipul M Parmar, Lindsay Perusek, Anouk Georges, Masayo Takahashi, John W Crabb, Akiko Maeda
It has become increasingly important to understand how retinal inflammation is regulated because inflammation plays a role in retinal degenerative diseases. Lipocalin 2 (LCN2), an acute stress response protein with multiple innate immune functions, is increased in ATP-binding cassette subfamily A member 4 ( Abca4 ) -/- retinol dehydrogenase 8 ( Rdh8 ) -/- double-knockout mice, an animal model for Stargardt disease and age-related macular degeneration (AMD). To examine roles of LCN2 in retinal inflammation and degeneration, Lcn2-/- Abca4-/- Rdh8-/- triple-knockout mice were generated...
March 30, 2018: Journal of Immunology: Official Journal of the American Association of Immunologists
Antony Orth, Martin Ploschner, Ivan S Maksymov, Brant C Gibson
Compact microendoscopes use multicore optical fibers (MOFs) to visualize hard-to-reach regions of the body. These devices typically have a large numerical aperture (NA) and are fixed-focus, leading to blurry images from a shallow depth of field with little focus control. In this work, we demonstrate a method to digitally adjust the collection aperture and therefore extend the depth of field of lensless MOF imaging probes. We show that the depth of field can be more than doubled for certain spatial frequencies, and observe a resolution enhancement of up to 78% at a distance of 50μm from the MOF facet...
March 5, 2018: Optics Express
Sergio A Vázquez-Córdova, Shanmugam Aravazhi, Christos Grivas, Yean-Sheng Yong, Sonia M García-Blanco, Jennifer L Herek, Markus Pollnau
We report on the optical-gain properties of channel waveguides patterned into lattice-matched KGdxLuyEr1- x- y(WO4 )2 layers grown onto undoped KY(WO4 )2 substrates by liquid phase epitaxy. A systematic investigation of gain is performed for five different Er3+ concentrations in the range of 0.75 to 10at.% and different pump powers and signal wavelengths. In pump-probe-beam experiments, relative internal gain, i.e., signal enhancement minus absorption loss of light propagating in the channel waveguide, is experimentally demonstrated, with a maximum value of 12 ± 5 dB/cm for signals at the peak-emission wavelength of 1534...
March 5, 2018: Optics Express
Jing Zhu, Pei Zhang, Dongxu Chen, Ruifeng Liu, Yingnan Zhou, Jinwen Wang, Hong Gao, Fuli Li
Precisely determining the topological charge (TC) of both integral Bessel beams (IBB) and fractional Bessel beams (FBB) is a key issue for their applications. However, most of the common methods could not probe both the IBB and FBB precisely and robustly. In this paper, we present a robust method to probe the topological charge of a Bessel beam by dynamic angular double slits (ADSs). We find that when a Bessel beam vertically illuminates on a dynamic ADS, the information of the TC can be retrieved from its Fourier transform patterns near the optical axis...
March 1, 2018: Applied Optics
Ya-Nan Bao, Yi-Wei Zeng, Ran Guo, Mesude Ablikim, Hai-Fang Shi, Li-Min Yang, Zhan-Lan Yang, Yi-Zhuang Xu, Isao Noda, Jin-Guang Wu
3 A 2g → 3 T 1g (P) transition band of Ni 2+ is used to probe the coordination of Ni 2+ . Two-dimensional asynchronous spectra (2DCOS) are generated using the Double Asynchronous Orthogonal Sample Design (DAOSD), Asynchronous Spectrum with Auxiliary Peaks (ASAP) and Two-Trace Two-Dimensional (2T2D) approaches. Cross peaks relevant to the 3 A 2g → 3 T 1g (P) transition band of Ni 2+ are utilized to probe coordination between Ni 2+ and various ligands. We studied the spectral behavior of the 3 A 2g → 3 T 1g (P) transition band when Ni 2+ is coordinated with ethylenediaminetetraacetic acid disodium salt (EDTA)...
December 7, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Yonas Muanenda, Stefano Faralli, Claudio J Oton, Fabrizio Di Pasquale
We propose and experimentally demonstrate a stable homodyne phase demodulation technique in a ϕ-OTDR using a double-pulse probe and a simple direct detection receiver. The technique uses selective phase modulation of one of a pair of pulses to generate a carrier for dynamic phase changes and involves an enhanced phase demodulation scheme suitable for distributed sensing by being robust against light intensity fluctuations, independent of the modulation depth, and convenient for analogue signal processing. The capability of the technique to quantify distributed dynamic phase change due to a generic external impact is experimentally demonstrated by measuring the phase change induced by a nonlinear actuator generating a 2 kHz perturbation at a distance of 1...
January 22, 2018: Optics Express
Marco Giannelli, Fabrizio Materassi, Tiziana Fossi, Luca Lorenzini, Daniele Bani
Broad methodological heterogeneity makes the literature on the clinical effects of laser treatment in periodontitis, both as monotherapy and adjunct to non-surgical therapy, which is difficult to interpret. The present split-mouth study was performed: (i) to determine the efficacy and safety of a photoablative-photodynamic diode laser therapy, including antiseptic LED irradiation, in adjunct to scaling and root planing (iPAPD+SRP) vs. sham-treatment+SRP for the treatment of diffuse severe periodontitis and (ii) to estimate the patient-reported outcomes...
January 18, 2018: Lasers in Medical Science
Furu Zhang, Jianhui Zhou, Di Xiao, Yugui Yao
Band inversion has led to rich physical effects in both topological insulators and topological semimetals. It has been found that the inverted band structure with the Mexican-hat dispersion could enhance the interband correlation leading to a strong intrinsic plasmon excitation. Its frequency ranges from several meV to tens of meV and can be effectively tuned by the external fields. The electron-hole asymmetric term splits the peak of the plasmon excitation into double peaks. The fate and properties of this plasmon excitation can also act as a probe to characterize the topological phases even in lightly doped systems...
December 29, 2017: Physical Review Letters
David A Marchiori, Paul H Oyala, Richard J Debus, Troy A Stich, R David Britt
The Mn4 CaO5 oxygen-evolving complex (OEC) of photosystem II catalyzes the light-driven oxidation of two substrate waters to molecular oxygen. ELDOR-detected NMR along with computational studies indicated that ammonia, a substrate analogue, binds as a terminal ligand to the Mn4A ion trans to the O5 μ4 oxido bridge. Results from electron spin echo envelope modulation (ESEEM) spectroscopy confirmed this and showed that ammonia hydrogen bonds to the carboxylate side chain of D1-Asp61. Here we further probe the environment of OEC with an emphasis on the proximity of exchangeable protons, comparing ammonia-bound and unbound forms...
February 8, 2018: Journal of Physical Chemistry. B
Hu Lei, Paul-Ludovic Karsenti, Pierre D Harvey
The notoriously non-luminescent uncycled azophenine (Q) was harnessed with Bodipy and zinc(II)porphyrin antennas to probe its fluorescence properties, its ability to act as a singlet excited state energy acceptor and to mediate the transfer. Two near-IR emissions are depicted from time-resolved fluorescence spectroscopy, which are most likely due to the presence of tautomers of very similar calculated total energies (350 cm-1 ; DFT; B3LYP). The rates for energy transfer, kET (S1 ), for1 Bodipy*→Q are in the order of 1010 -1011  s-1 and are surprisingly fast when considering the low absorptivity properties of the lowest energy charge transfer excited state of azophenine...
March 5, 2018: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
Stéphanie Mendes Marinho, Minh-Huong Ha-Thi, Van-Thai Pham, Annamaria Quaranta, Thomas Pino, Christophe Lefumeux, Thierry Chamaillé, Winfried Leibl, Ally Aukauloo
Biomimetic models that contain elements of photosynthesis are fundamental in the development of synthetic systems that can use sunlight to produce fuel. The critical task consists of running several rounds of light-induced charge separation, which is required to accumulate enough redox equivalents at the catalytic sites for the target chemistry to occur. Long-lived first charge-separated state and distinct electronic signatures for the sequential charge accumulated species are essential features to be able to track these events on a spectroscopic ground...
December 11, 2017: Angewandte Chemie
Amira F El-Yazbi, Alysha Wong, Glen R Loppnow
The human genome is susceptible to change; base mismatches can arise from damaged DNA, replication errors, and spontaneous mutation, and have the potential to cause apoptosis, carcinogenesis, and mutagenesis. Many techniques have been developed for DNA mismatch detection, but many of these methods have complex, time-consuming procedures and are limited to the detection of specific types of DNA mismatches. In this work, we present a general method for the simple and sensitive nucleobase-sensitized luminescent detection of mismatches in double-stranded DNA (dsDNA) using terbium ions...
November 22, 2017: Analytica Chimica Acta
Matthew Blain-Hartung, Nathan C Rockwell, J Clark Lagarias
Phytochromes and cyanobacteriochromes (CBCRs) use double-bond photoisomerization of their linear tetrapyrrole (bilin) chromophores within cGMP-specific phosphodiesterases/adenylyl cyclases/FhlA (GAF) domain-containing photosensory modules to regulate activity of C-terminal output domains. CBCRs exhibit photocycles that are much more diverse than those of phytochromes and are often found in large modular proteins such as Tlr0924 (SesA), one of three blue light regulators of cell aggregation in the cyanobacterium Thermosynechococcus elongatus...
November 21, 2017: Biochemistry
Lei Zhang, Douglas K Pleskow, Vladimir Turzhitsky, Eric U Yee, Tyler M Berzin, Mandeep Sawhney, Shweta Shinagare, Edward Vitkin, Yuri Zakharov, Umar Khan, Fen Wang, Jeffrey D Goldsmith, Saveli Goldberg, Ram Chuttani, Irving Itzkan, Le Qiu, Lev T Perelman
Pancreatic cancers are usually detected at an advanced stage and have poor prognosis. About one fifth of these arise from pancreatic cystic lesions. Yet not all lesions are precancerous, and imaging tools lack adequate accuracy for distinguishing precancerous from benign cysts. Therefore, decisions on surgical resection usually rely on endoscopic ultrasound-guided fine needle aspiration (EUS-FNA). Unfortunately, cyst fluid often contains few cells, and fluid chemical analysis lacks accuracy, resulting in dire consequences, including unnecessary pancreatic surgery for benign cysts and the development of cancer...
2017: Nature Biomedical Engineering
Tao Zhang, Feng Gao, Xiangqian Jiang
This paper proposes an approach to measure double-sided near-right-angle structured surfaces based on dual-probe wavelength scanning interferometry (DPWSI). The principle and mathematical model is discussed and the measurement system is calibrated with a combination of standard step-height samples for both probes vertical calibrations and a specially designed calibration artefact for building up the space coordinate relationship of the dual-probe measurement system. The topography of the specially designed artefact is acquired by combining the measurement results with white light scanning interferometer (WLSI) and scanning electron microscope (SEM) for reference...
October 2, 2017: Optics Express
R Margutti, B D Metzger, R Chornock, D Milisavljevic, E Berger, P K Blanchard, C Guidorzi, G Migliori, A Kamble, R Lunnan, M Nicholl, D L Coppejans, S Dall'Osso, M R Drout, R Perna, B Sbarufatti
We present the detection of persistent soft X-ray radiation with Lx ~ 10(41)-10(42) erg s(-1) at the location of the extremely luminous, double-humped transient ASASSN-15lh as revealed by Chandra and Swift. We interpret this finding in the context of observations from our multiwavelength campaign, which revealed the presence of weak narrow nebular emission features from the host-galaxy nucleus and clear differences with respect to superluminous supernova optical spectra. Significant UV flux variability on short timescales detected at the time of the rebrightening disfavors the shock interaction scenario as the source of energy powering the long-lived UV emission, while deep radio limits exclude the presence of relativistic jets propagating into a low-density environment...
February 10, 2017: Astrophysical Journal
Misha Liu, Jinjin Xu, Fan Yang, Yifan Gu, Huan Chen, Ying Wang, Fengting Li
Detection of DNA damage caused by ∙OH or radiation has led to rapidly growing interest in the fields of drug development, biochemistry, clinic diagnostics, and environmental evaluation. Electrochemical methods have been applied for DNA damage detection because of their fast and sensitive response. However, most of the electrochemical methods for DNA damage detection commonly require immobilization of the strands on the electrode surface. In the present work, sensitive electrochemical monitoring of DNA damage was realized successfully on the basis of in situ DNA chain growth by use of a hybridization chain reaction (HCR) technique...
November 2017: Analytical and Bioanalytical Chemistry
Natalie R Fetto, Wenqiang Cao, Ian S Wallace, Matthew J Tucker
Recently, it has been shown that nitrile-derivatized phenylalanines possess distinct fluorescent properties depending on the position of the cyano-group within the aromatic ring. These fluorophores have potential as probes for studying protein dynamics due to their sensitivity to local environment. Herein, we demonstrate that 2-cyanophenylalanine (Phe2CN) and Phe4CN can independently monitor multiple sites during the Ca(2+) dependent binding of a skeletal muscle myosin light chain kinase (MLCK) peptide fragment to the protein calmodulin (CaM)...
October 6, 2017: Journal of Physical Chemistry. B
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