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double probe light

Panwang Zhou, Keli Han
As one of the most fundamental processes, excited-state proton transfer (ESPT) plays a major role in both chemical and biological systems. In the past several decades, experimental and theoretical studies on ESPT systems have attracted considerable attention because of their tremendous potential in fluorescent probes, biological imaging, white-light-emitting materials, and organic optoelectronic materials. ESPT is related to fluorescence properties and usually occurs on an ultrafast time scale at or below 100 fs...
June 15, 2018: Accounts of Chemical Research
Hamdi Joda, Angeliki Moutsiopoulou, Geoffrey Stone, Sylvia Daunert, Sapna Deo
Here we describe the design of a bioluminescent stem-loop probe for the sensitive detection of HIV-1 spliced RNA. In this study, we employed Gaussia luciferase (GLuc), a bioluminescent protein that has several advantages over other bioluminescent proteins, including smaller size, higher bioluminescent intensity, and chemical and thermal stability. GLuc was chemically conjugated to the DABCYL-modified stem-loop probe (SLP) and was purified with a 2-step process to remove unconjugated GLuc and SLP. The binding of the target RNA to the loop region of the SLP results in the open conformation separating the stem part of SLP...
June 13, 2018: Analyst
Zhaojing Ba, Min Hu, Yiming Zhao, Yiqing Wang, Jing Wang, Zhenxi Zhang
Non-contact thermal sensors are important devices to study cellular processes and monitor temperature in vivo. Herein, a novel highly sensitive nanothermometer based on NaYF4:Yb,Er@ NaYF4@NaYF4:Yb,Tm@ NaYF4:Nd (denoted as Er@Y@Tm@Nd) was prepared by a facile solvothermal method. When excited by the NIR light of 808 and 980 nm, the as-prepared Er@Y@Tm@Nd nanoparticles could emit both blue and green light respectively, since the lanthanide cations responsible for these emissions are gathered inside this nanostructure...
June 4, 2018: Nanotechnology
Chanelle C Jumper, Ivo H M van Stokkum, Tihana Mirkovic, Gregory D Scholes
Determining the key features of high efficiency photosynthetic energy transfer remains an ongoing task. Recently, there has been evidence for the role of vibronic coherence in linking donor and acceptor states to redistribute oscillator strength for enhanced energy transfer. In order to gain further insights into the interplay between vibronic wavepackets and energy transfer dynamics, we systematically compare four structurally related phycobiliproteins from cryptophyte algae by broadband pump probe spectroscopy and extend a parametric model based on global analysis to include vibrational wavepacket characterization...
May 30, 2018: Journal of Physical Chemistry. B
Sariga C Lal, Vidhya Lalan, Subodh Ganesanpotti
Ba2 Ln2/3 TeO6 (Ln = La, Pr, Nd, Sm, and Eu) double perovskites were synthesized via solid-state ceramic route. Preliminary X-ray diffraction studies indicated a pseudocubic structure with lattice parameters ranging from 8.55 to 8.44 Å for the substitution of rare earths from La to Eu. Raman spectra show the frequency dependence of various Raman bands with respect to rare-earth substitution and exhibit a significant shift in peaks to higher wavenumber region, which was observed only for symmetric stretching modes of LnO6 and TeO6 octahedra...
May 17, 2018: Inorganic Chemistry
Pijush K Mandal, Vaishali Naik, Vas Dev, Alok Chakrabarti, Ayan Ray
In this work, we address the issue of the suitability of blue fluorescent light as a frequency offset reference during the ladder-level excitation 5S1/2 →5P3/2 →5D3/2 of Rb85 atoms. A simple pump-probe spectroscopy experiment is performed to generate non-degenerate blue light emission produced by the spontaneous decay route 5D3/2 →6P3/2 →5S1/2 . By varying the relative intensity of the pump-probe combination, we can hover between regimes dominated by mechanisms such as double resonance optical pumping (DROP) and Autler-Townes splitting...
May 1, 2018: Applied Optics
Sven Achenbach, Garth Wells, Chen Shen
In deep X-ray lithography (DXRL), synchrotron radiation is applied to pattern polymer microstructures. At the Synchrotron Laboratory for Micro and Nano Devices (SyLMAND), Canadian Light Source, a chromium-coated grazing-incidence X-ray double-mirror system is applied as a tunable low-pass filter. In a systematic study, the surface conditions of the two mirrors are analyzed to determine the mirror reflectivity for DXRL process optimization, without the need for spectral analysis or surface probing: PMMA resist foils were homogeneously exposed and developed to determine development rates for mirror angles between 6 mrad and 12 mrad as well as for white light in the absence of the mirrors...
May 1, 2018: Journal of Synchrotron Radiation
Huihui Mao, Guanghua Luo, Yuxia Zhan, Jun Zhang, Shuang Yao, Yang Yu
The base-quenched probe method for detecting single nucleotide polymorphisms (SNPs) relies on real-time PCR and melting-curve analysis, which might require only one pair of primers and one probe. At present, it has been successfully applied to detect SNPs of multiple genes. However, the mechanism of the base-quenched probe method remains unclear. Therefore, we investigated the possible mechanism of fluorescence quenching by DNA bases in aqueous solution using spectroscopic techniques. It showed that the possible mechanism might be photo-induced electron transfer...
April 30, 2018: Analyst
Guang Yang, Yong Cao, Bin Yan, Qiang Lv, Jianbo Yu, Fusheng Zhao, Zhihong Chen, Heran Yang, Mengxi Chen, Zaishun Jin
Upconversion nanoparticles are a new type of fluorescent marker in biomedical imaging that can convert a longer wavelength (such as near-infrared fluorescence) into a shorter wavelength (such as visible light). Mantle cell lymphoma, which is derived from B-cell lymphoma, is a subtype of non-Hodgkin's lymphoma, and the immune phenotype is a mature B-cell phenotype (CD20+, CD5+). To develop the use of nanomaterials as specific markers for the medical imaging of mantle cell lymphoma, we modified the surface of UCNPs by oxidation so that the CD20 or CD5 antibody could covalently attach to the upconversion nanoparticles to form antibody-UCNP conjugates...
March 30, 2018: Oncotarget
Ioannis Panagopoulos, Ludmila Gorunova, Eva-Marie Jacobsen, Kristin Andersen, Francesca Micci, Sverre Heim
Leukemic cells often carry chromosome aberrations which generate chimeric genes of pathogenetic, diagnostic, and prognostic importance. New rearrangements giving rise to novel fusion genes define hitherto unrecognized genetic leukemia subgroups. G-banding, fluorescence in situ hybridization (FISH), and molecular genetic analyses were done on bone marrow cells from a patient with chronic lymphocytic leukemia (CLL) and secondary myelodysplasia. The G-banding analysis revealed the karyotype 46,XX,del(21)(q22)[9]/46,XX[2]...
2018: PloS One
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...
May 1, 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 A2g →3 T1g (P) transition band of Ni2+ is used to probe the coordination of Ni2+ . 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 A2g →3 T1g (P) transition band of Ni2+ are utilized to probe coordination between Ni2+ and various ligands. We studied the spectral behavior of the 3 A2g →3 T1g (P) transition band when Ni2+ is coordinated with ethylenediaminetetraacetic acid disodium salt (EDTA)...
May 15, 2018: 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
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