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"Timing gate"

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https://www.readbyqxmd.com/read/28380946/phase-detection-distributed-fiber-optic-vibration-sensor-without-fading-noise-based-on-time-gated-digital-ofdr
#1
Dian Chen, Qingwen Liu, Zuyuan He
For a distributed fiber-optic vibration sensor (DFVS), the vibration signal extracted from the phase of backscattering has a linear response to the applied vibration, and is more attractive than that from the intensity term. However, the large phase noise at a random weak-fading-point seriously limits the sensor's credibility. In this paper, a novel phase-detection DFVS is developed, which effectively eliminates the weak-fading-point. The relationship between phase noise and the intensity of backscattering is analyzed, and the inner-pulse frequency-division method and rotated-vector-sum method are introduced to effectively suppress phase noise...
April 3, 2017: Optics Express
https://www.readbyqxmd.com/read/28371153/multiplexed-nucleic-acid-hybridization-assays-using-single-fret-pair-distance-tuning
#2
Xue Qiu, Jiajia Guo, Zongwen Jin, Igor L Medintz, Niko Hildebrandt
Multiplexed photoluminescence (PL) detection plays an important role in chemical and biological sensing. Here, it is shown that time-gated (TG) detection of a single terbium-donor-based Förster resonance energy transfer (FRET) pair can be used to selectively quantify low nanomolar concentrations of multiple DNAs or microRNAs in a single sample. This study demonstrates the applicability of single-TG-FRET-pair multiplexing for molecular (Tb-to-dye) and nanoparticle (Tb-to-quantum-dot) biosensing. Both systems use acceptor-sensitization and donor-quenching for quantifying biomolecular recognition and modification of the donor-acceptor distance for tuning the PL decays...
April 3, 2017: Small
https://www.readbyqxmd.com/read/28361130/a-luminogenic-lanthanide-based-probe-for-the-highly-selective-detection-of-nanomolar-sulfide-levels-in-aqueous-samples
#3
Margaret L Aulsebrook, Suvendu Biswas, Franklin M Leaver, Michael R Grace, Bim Graham, Amy M Barrios, Kellie L Tuck
A bimetallic terbium(iii)/copper(ii) complex (Tb-1·Cu2+) for the time-gated luminescent detection of hydrogen sulfide in aqueous samples is reported. The probe shows excellent selectivity towards HS(-) over various anions and cations, including the ions common to natural waterways and waste water samples, displaying a 73-fold increase in luminescence in the presence of sulfide. The probe exhibits extremely fast reaction times and a low limit of detection (130 nM). The probe was used to quantify sulfide in an industrial "sour water" sample, with the result in excellent agreement with those from two independent assay methods (methylene blue and AzMC)...
March 31, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28358111/fluorescent-nanodiamonds-enable-quantitative-tracking-of-human-mesenchymal-stem-cells-in-miniature-pigs
#4
Long-Jyun Su, Meng-Shiue Wu, Yuen Yung Hui, Be-Ming Chang, Lei Pan, Pei-Chen Hsu, Yit-Tsong Chen, Hong-Nerng Ho, Yen-Hua Huang, Thai-Yen Ling, Hsao-Hsun Hsu, Huan-Cheng Chang
Cell therapy is a promising strategy for the treatment of human diseases. While the first use of cells for therapeutic purposes can be traced to the 19th century, there has been a lack of general and reliable methods to study the biodistribution and associated pharmacokinetics of transplanted cells in various animal models for preclinical evaluation. Here, we present a new platform using albumin-conjugated fluorescent nanodiamonds (FNDs) as biocompatible and photostable labels for quantitative tracking of human placenta choriodecidual membrane-derived mesenchymal stem cells (pcMSCs) in miniature pigs by magnetic modulation...
March 30, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28322053/development-of-a-novel-lysosome-targeted-ruthenium-ii-complex-for-phosphorescence-time-gated-luminescence-assay-of-biothiols
#5
Quankun Gao, Wenzhu Zhang, Bo Song, Run Zhang, Weihua Guo, Jingli Yuan
Considering the important roles of biothiols in lysosomes of live organisms, and unique photophysical/photochemical properties of ruthenium(II) complexes, a novel ruthenium(II) complex, Ru-2, has been developed as a molecular probe for phosphorescence and time-gated luminescence assay of biothiols in human sera, live cells, and in vivo. Ru-2 is weakly luminescent due to the effective photoinduced electron transfer (PET) from Ru(II) luminophore to electron acceptor, 2,4-dinitrobenzene-sulfonyl (DNBS). In the presence of biothiols, such as glutathione (GSH), cysteine (Cys), and homocysteine (Hcy), the emission of Ru-2 solution was switched ON, as a result of the cleavage of quencher to form the product, Ru-1...
March 31, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28277431/validity-of-single-beam-timing-lights-at-different-heights
#6
Stefan Altmann, Max Spielmann, Florian Engel, Rainer Neumann, Steffen Ringhof, Doris Oriwol, Sascha Haertel
The purpose of this study was to quantify the effect of different timing light heights on sprint time and the validity of measurement. Two single beam timing gate systems were used to measure 30-m sprint time (splits at 5 m and 10 m) in 15 healthy and physically active male subjects. System 1 was set up at a height of 0.64 m, system 2 at 0.25 m (initial timing light) and 1.00 m (each following timing light), respectively. Participants performed three valid trials. The recordings of a high-speed video camera were used as a reference...
March 8, 2017: Journal of Strength and Conditioning Research
https://www.readbyqxmd.com/read/28276345/development-of-a-novel-europium-complex-based-luminescent-probe-for-time-gated-luminescence-imaging-of-hypochlorous-acid-in-living-samples
#7
Xiangli Liu, Lianying Guo, Bo Song, Zhixin Tang, Jingli Yuan
Luminescent lanthanide complexes are key reagents used in the time-gated luminescence bioassay technique, but functional lanthanide complexes that can act as luminescent probes for specifically responding to analytes are very limited. In this work, we designed and synthesized a novel Eu(3+) complex-based luminescence probe for hypochlorous acid (HOCl), NPPTTA-Eu(3+), by using terpyridine polyacid-Eu(3+), dinitrophenyl, and hydrazine as luminophore, quencher and HOCl-recognizer moieties, respectively. In the absence of HOCl, the probe is non-luminescent due to the strong luminescence quenching of the dinitrophenyl group in the complex...
March 9, 2017: Methods and Applications in Fluorescence
https://www.readbyqxmd.com/read/28238259/versatile-spectral-and-lifetime-multiplexing-nanoplatform-with-excitation-orthogonalized-upconversion-luminescence
#8
Hao Dong, Ling-Dong Sun, Wei Feng, Yuyang Gu, Fuyou Li, Chun-Hua Yan
Optical encoding together with color multiplexing benefits on-site detection, and enriching the components with narrow emissions from lanthanide could greatly increase the coding density. Here, we show a typical example to combine emission color and lifetime that are simultaneously integrated in a single lanthanide nanoparticle. With the multicompartment core/shell structure, the nanoparticles can activate different emitting pathways under varied excitation. This enables the nanoparticles to generate versatile excitation orthogonalized upconversion luminescence in both emission colors and lifetimes...
March 28, 2017: ACS Nano
https://www.readbyqxmd.com/read/28192308/fluorescence-lifetime-imaging-with-time-gated-detection-of-hyaluronidase-using-a-long-lifetime-azadioxatriangulenium-adota-fluorophore
#9
Rahul Chib, Sebastian Requena, Mark Mummert, Yuri M Strzhemechny, Ignacy Gryczynski, Julian Borejdo, Zygmunt Gryczynski, Rafal Fudala
A fluorescence lifetime imaging probe with a long lifetime was used in combination with time-gating for the detection of hyaluronidase using hyaluronic acid as the probe template. This probe was developed by heavily labeling hyaluronic acid with long lifetime azadioxatriangulenium fluorophores (ADOTA). We used this probe to image hyaluronidase produced by DU-145 prostate cancer cells.
November 17, 2016: Methods and Applications in Fluorescence
https://www.readbyqxmd.com/read/28169363/image-reconstruction-from-photon-sparse-data
#10
Lena Mertens, Matthias Sonnleitner, Jonathan Leach, Megan Agnew, Miles J Padgett
We report an algorithm for reconstructing images when the average number of photons recorded per pixel is of order unity, i.e. photon-sparse data. The image optimisation algorithm minimises a cost function incorporating both a Poissonian log-likelihood term based on the deviation of the reconstructed image from the measured data and a regularization-term based upon the sum of the moduli of the second spatial derivatives of the reconstructed image pixel intensities. The balance between these two terms is set by a bootstrapping technique where the target value of the log-likelihood term is deduced from a smoothed version of the original data...
February 7, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28154873/a-low-cost-smartphone-based-platform-for-highly-sensitive-point-of-care-testing-with-persistent-luminescent-phosphors
#11
Andrew S Paterson, Balakrishnan Raja, Vinay Mandadi, Blane Townsend, Miles Lee, Alex Buell, Binh Vu, Jakoah Brgoch, Richard C Willson
Through their computational power and connectivity, smartphones are poised to rapidly expand telemedicine and transform healthcare by enabling better personal health monitoring and rapid diagnostics. Recently, a variety of platforms have been developed to enable smartphone-based point-of-care testing using imaging-based readout with the smartphone camera as the detector. Fluorescent reporters have been shown to improve the sensitivity of assays over colorimetric labels, but fluorescence readout necessitates incorporating optical hardware into the detection system, adding to the cost and complexity of the device...
March 14, 2017: Lab on a Chip
https://www.readbyqxmd.com/read/28149358/muscle-strength-and-speed-performance-in-youth-soccer-players
#12
Luis Peñailillo, Francisco Espíldora, Sebastián Jannas-Vela, Iñigo Mujika, Hermann Zbinden-Foncea
This study aimed to examine the relationship between maximum leg extension strength and sprinting performance in youth elite male soccer players. Sixty-three youth players (12.5 ± 1.3 years) performed 5 m, flying 15 m and 20 m sprint tests and a zigzag agility test on a grass field using timing gates. Two days later, subjects performed a one-repetition maximum leg extension test (79.3 ± 26.9 kg). Weak to strong correlations were found between leg extension strength and the time to perform 5 m (r = -0.39, p = 0...
April 1, 2016: Journal of Human Kinetics
https://www.readbyqxmd.com/read/28147687/characterisation-of-new-gated-optical-image-intensifiers-for-fluorescence-lifetime-imaging
#13
H Sparks, F Görlitz, D J Kelly, S C Warren, P A Kellett, E Garcia, A K L Dymoke-Bradshaw, J D Hares, M A A Neil, C Dunsby, P M W French
We report the characterisation of gated optical image intensifiers for fluorescence lifetime imaging, evaluating the performance of several different prototypes that culminate in a new design that provides improved spatial resolution conferred by the addition of a magnetic field to reduce the lateral spread of photoelectrons on their path between the photocathode and microchannel plate, and higher signal to noise ratio conferred by longer time gates. We also present a methodology to compare these systems and their capabilities, including the quantitative readouts of Förster resonant energy transfer...
January 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28107952/lanthanide-coordination-polymer-probe-for-time-gated-luminescence-sensing-of-ph-in-undiluted-human-serum
#14
Yankai Huang, Baoxia Liu, Qi Shen, Xu Zhu, Yuanqiang Hao, Zhu Chang, Fang Xu, Peng Qu, Maotian Xu
Lanthanide coordination polymers (LCPs) have emerged as fascinating materials because of their specific structure and properties. In this work, utilizing hydrosoluble biomolecule of guanosine-5'-monophosphate (GMP) as bridging linker, lanthanide terbium ions (Tb(3+)) as metal nodes, and silver ions (Ag(+)) as sensitizers, we synthesized a pH responsive luminescent lanthanide CP probe of Tb/GMP/Ag. The probe possesses high luminescence due to the sensitization of Ag(+); While in alkaline solutions, Ag(+) in Tb/GMP/Ag immediately binds to OH(-), forming Ag2O precipitation and resulting in a distinct fluorescence quenching of Tb/GMP/Ag...
March 1, 2017: Talanta
https://www.readbyqxmd.com/read/28045838/effect-of-context-and-hearing-loss-on-time-gated-word-recognition-in-children
#15
Dawna Lewis, Judy Kopun, Ryan McCreery, Marc Brennan, Kanae Nishi, Evan Cordrey, Pat Stelmachowicz, Mary Pat Moeller
OBJECTIVES: The purpose of this study was to examine word recognition in children who are hard of hearing (CHH) and children with normal hearing (CNH) in response to time-gated words presented in high- versus low-predictability sentences (HP, LP), where semantic cues were manipulated. Findings inform our understanding of how CHH combine cognitive-linguistic and acoustic-phonetic cues to support spoken word recognition. It was hypothesized that both groups of children would be able to make use of linguistic cues provided by HP sentences to support word recognition...
December 30, 2016: Ear and Hearing
https://www.readbyqxmd.com/read/28031755/performance-effects-of-repetition-specific-gluteal-activation-protocols-on-acceleration-in-male-rugby-union-players
#16
Lorna Barry, Ian Kenny, Thomas Comyns
Warm-up protocols have the potential to cause an acute enhancement of dynamic sprinting performance. The purpose of this study was to evaluate the effects of three repetition specific gluteal activation warm-up protocols on acceleration performance in male rugby union players. Forty male academy rugby union players were randomly assigned to one of 4 groups (control, 5, 10 or 15 repetition gluteal activation group) and performed 10 m sprints at baseline and 30 s, 2, 4, 6 and 8 min after their specific intervention protocol...
December 1, 2016: Journal of Human Kinetics
https://www.readbyqxmd.com/read/28008417/time-domain-diffuse-correlation-spectroscopy
#17
Jason Sutin, Bernhard Zimmerman, Danil Tyulmankov, Davide Tamborini, Kuan Cheng Wu, Juliette Selb, Angelo Gulinatti, Ivan Rech, Alberto Tosi, David A Boas, Maria Angela Franceschini
Physiological monitoring of oxygen delivery to the brain has great significance for improving the management of patients at risk for brain injury. Diffuse correlation spectroscopy (DCS) is a rapidly growing optical technology able to non-invasively assess the blood flow index (BFi) at the bedside. The current limitations of DCS are the contamination introduced by extracerebral tissue and the need to know the tissue's optical properties to correctly quantify the BFi. To overcome these limitations, we have developed a new technology for time-resolved diffuse correlation spectroscopy...
September 2016: Optica
https://www.readbyqxmd.com/read/27991773/all-solution-based-aggregation-control-in-solid-state-photon-upconverting-organic-model-composites
#18
Hossein Goudarzi, Panagiotis E Keivanidis
Hitherto, great strides have been made in the development of organic systems that exhibit triplet-triplet annihilation-induced photon-energy upconversion (TTA-UC). Yet, the exact role of intermolecular states in solid-state TTA-UC composites remains elusive. Here we perform a comprehensive spectroscopic study in a series of solution-processable solid-state TTA-UC organic composites with increasing segregated phase content for elucidating the impact of aggregate formation in their TTA-UC properties. Six different states of aggregation are reached in composites of the 9,10-diphenylanthracene (DPA) blue emitter mixed with the (2,3,7,8,12,13,17,18-octaethylporphyrinato)platinum(II) sensitizer (PtOEP) in a fixed nominal ratio (2 wt % PtOEP)...
December 19, 2016: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/27934026/two-photon-absorbing-phosphorescent-metalloporphyrins-effects-of-%C3%AF-extension-and-peripheral-substitution
#19
Tatiana V Esipova, Héctor J Rivera-Jacquez, Bruno Weber, Artëm E Masunov, Sergei A Vinogradov
The ability to form triplet excited states upon two-photon excitation is important for several applications of metalloporphyrins, including two-photon phosphorescence lifetime microscopy (2PLM) and two-photon photodynamic therapy (PDT). Here we analyzed one-photon (1P) and degenerate two-photon (2P) absorption properties of several phosphorescent Pt (II) porphyrins, focusing on the effects of aromatic π-extension and peripheral substitution on triplet emissivity and two-photon absorption (2PA). Our 2PA measurements for the first time made use of direct time-resolved detection of phosphorescence, having the ability to efficiently reject laser background through microsecond time gating...
December 7, 2016: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/27909845/a-fluorescence-sensor-for-lead-ii-ions-determination-based-on-label-free-gold-nanoparticles-gnps-dnazyme-using-time-gated-mode-in-aqueous-solution
#20
Xiao-Yu Wang, Cheng-Gang Niu, Li-Juan Guo, Liu-Yin Hu, Sheng-Quan Wu, Guang-Ming Zeng, Fei Li
This paper describes a label-free 17E DNAzyme-based time-gated fluorescence sensor for Pb(2+) detection by unmodified gold nanoparticles (GNPs) and a terbium ternary complex. The fluorophore that used in this paper is a terbium ternary complex. Its signal can be measured in a time-gated manner which could eliminate most of the unspecific fluorescent background. It is well known that unfolded single-stranded DNA (ssDNA) could be adsorbed on GNPs while double-stranded DNA could not. The cleavage of the substrate by the 17E DNAzyme in the presence of Pb(2+) causes the release of ssDNA from the 17E-17S duplex to be absorbed onto GNPs, preventing the aggregation of GNPs and then leading to a fluorescence decrease of terbium ternary complex...
December 1, 2016: Journal of Fluorescence
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