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"Timing gate"

Roberta Assante, Alberto Cuocolo
No abstract text is available yet for this article.
March 15, 2018: Journal of Nuclear Cardiology: Official Publication of the American Society of Nuclear Cardiology
Tiina Lipiäinen, Jenni Pessi, Parisa Movahedi, Juha Tapio Koivistoinen, Lauri Kurki, Mari Tenhunen, Jouko Yliruusi, Anne M Juppo, Jukka Heikkonen, Tapio Pahikkala, Clare J Strachan
Raman spectroscopy is widely used for quantitative pharmaceutical analysis, but a common obstacle to its use is sample fluorescence masking the Raman signal. Time-gating provides an instrument-based method for rejecting fluorescence through temporal resolution of the spectral signal, and allows Raman spectra of fluorescent materials to be obtained. An additional practical advantage is that analysis is possible in ambient lighting. This study assesses the efficacy of time-gated Raman spectroscopy for the quantitative measurement of fluorescent pharmaceuticals...
March 7, 2018: Analytical Chemistry
Marcelina Cardoso Dos Santos, Joan Goetz, Hortense Bartenlian, Ka-Leung Wong, Loïc Joanny Charbonniere, Niko Hildebrandt
Fluorescent nanoparticles (NPs) have become irreplaceable tools for advanced cellular and sub-cellular imaging. While very bright NPs require excitation with UV or visible light, which can create strong autofluorescence of biological components, NIR-excitable NPs without autofluorescence issues exhibit much lower brightness. Here, we show the application of a new type of surface-photosensitized terbium NPs (Tb-NPs) for autofluorescence-free intracellular imaging in live HeLa cells. Combination of exceptionally high brightness, high photostability, and long photoluminecence (PL) lifetimes for highly efficient suppression of the short-lived autofluorescence, allowed for time-gated PL imaging of intracellular vesicles over 72 h without toxicity and at extremely low Tb-NP concentrations down to 12 pM...
February 20, 2018: Bioconjugate Chemistry
Shi-Fan Xue, Zi-Han Chen, Xin-Yue Han, Zi-Yang Lin, Qi-Xian Wang, Min Zhang, Guoyue Shi
Recent years have witnessed the rapid development of pattern-based sensors due to their potential to detect and differentiate a wealth of analytes with only few probes. However, no one has found or used the combination of DNA and terbium(III) (Tb) as a pattern recognition system for largescale mix-and-measure assays. Here we report for the first time that DNA-sensitized Tb (DNA/Tb), as a label-free and versatile "chemical nose/tongue", can be employed for widescale time-gated luminescent (TGL) monitoring metal ions covering nearly the entire periodic table in a cost-effective fashion...
February 13, 2018: Analytical Chemistry
Matthias W Hoppe, Christian Baumgart, Ted Polglaze, Jürgen Freiwald
This study aimed to investigate the validity and reliability of global (GPS) and local (LPS) positioning systems for measuring distances covered and sprint mechanical properties in team sports. Here, we evaluated two recently released 18 Hz GPS and 20 Hz LPS technologies together with one established 10 Hz GPS technology. Six male athletes (age: 27±2 years; VO2max: 48.8±4.7 ml/min/kg) performed outdoors on 10 trials of a team sport-specific circuit that was equipped with double-light timing gates. The circuit included various walking, jogging, and sprinting sections that were performed either in straight-lines or with changes of direction...
2018: PloS One
Istvan Gyongy, Amy Davies, Benjamin Gallinet, Neale A W Dutton, Rory R Duncan, Colin Rickman, Robert K Henderson, Paul A Dalgarno
Single-photon avalanche photodiode (SPAD) image sensors offer time-gated photon counting, at high binary frame rates of >100 kFPS and with no readout noise. This makes them well-suited to a range of scientific applications, including microscopy, sensing and quantum optics. However, due to the complex electronics required, the fill factor tends to be significantly lower (< 10%) than that of EMCCD and sCMOS cameras (>90%), whilst the pixel size is typically larger, impacting the sensitivity and practicalities of the SPAD devices...
February 5, 2018: Optics Express
Zhongbo Du, Bo Song, Wenzhu Zhang, Chengchen Duan, Yong-Lei Wang, Chaolong Liu, Run Zhang, Jingli Yuan
Development of novel bioanalytical methods for monitoring of H2S is the key to understand the physiological and pathological functions of this gasotransmitter in live organisms. Herein, a ruthenium(II) complex-based luminescence probe, Ru-MDB, was developed by introducing a new H2S responsive masking moiety to red emitting RuII luminophore. Cleavage of this masking group by a H2S-triggered reaction leads to the luminescence "OFF-ON" response. The long-lived emissions of Ru-MDB and its reaction product with H2S allowed quantitative detection of H2S in autofluorescence-rich human sera and adult zebrafish organs with time-gated luminescence mode...
February 2, 2018: Angewandte Chemie
Kenneth Yin Zhang, Qi Yu, Huanjie Wei, Shujuan Liu, Qiang Zhao, Wei Huang
In this Review article, we systematically summarize the design and applications of various kinds of long-lived emissive probes for bioimaging and biosensing via time-resolved photoluminescence techniques. The probes reviewed, including lanthanides, transition-metal complexes, organic dyes, carbon and silicon nanoparticles, metal clusters, and persistent phosphores, exhibit longer luminescence lifetimes than that of autofluorescence from biological tissue and organs. When these probes are internalized into living cells or animals, time-gated photoluminescence imaging selectively collects long-lived signals for intensity analysis, while photoluminescence lifetime imaging reports the decay details of each pixel...
February 2, 2018: Chemical Reviews
Alejandro Bastida Castillo, Carlos D Gómez Carmona, Ernesto De la Cruz Sánchez, José Pino Ortega
There is interest in the accuracy and inter-unit reliability of position-tracking systems to monitor players. Research into this technology, although relatively recent, has grown exponentially in the last years, and it is difficult to find professional team sport that does not use Global Positioning System (GPS) technology at least. The aim of this study is to know the accuracy of both GPS-based and Ultra Wide Band (UWB)-based systems on a soccer field and their inter- and intra-unit reliability. A secondary aim is to compare them for practical applications in sport science...
January 31, 2018: European Journal of Sport Science
Jonathan M Zuidema, Tushar Kumeria, Dokyoung Kim, Jinyoung Kang, Joanna Wang, Geoffrey Hollett, Xuan Zhang, David S Roberts, Nicole Chan, Cari Dowling, Elena Blanco-Suarez, Nicola J Allen, Mark H Tuszynski, Michael J Sailor
Oriented composite nanofibers consisting of porous silicon nanoparticles (pSiNPs) embedded in a polycaprolactone or poly(lactide-co-glycolide) matrix are prepared by spray nebulization from chloroform solutions using an airbrush. The nanofibers can be oriented by an appropriate positioning of the airbrush nozzle, and they can direct growth of neurites from rat dorsal root ganglion neurons. When loaded with the model protein lysozyme, the pSiNPs allow the generation of nanofiber scaffolds that carry and deliver the protein under physiologic conditions (phosphate-buffered saline (PBS), at 37 °C) for up to 60 d, retaining 75% of the enzymatic activity over this time period...
January 24, 2018: Advanced Materials
S M Harris, K Srivastava, A B League, K E Ziebarth, V C Pierre
A family of terbium probes was synthesized and evaluated for the luminescence detection of copper and zinc in water at neutral pH. Each probe incorporates a terbium ion chelated by a macrocyclic polyaminocarboxylate and conjugated to either one, two, or three phenanthridine antennas via a diamine linker. All three probes, Tb-1Phen, Tb-2Phen, and Tb-3Phen, exhibit similar responses toward copper and zinc. In each case, the terbium-centered time-gated phosphorescence decreases upon binding either CuI or CuII but not upon addition of ZnII...
January 24, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
Rene Nkoulou, Mathias Wolfrum, Aju P Pazhenkottil, Michael Fiechter, Ronny R Buechel, Oliver Gaemperli, Philipp A Kaufmann
BACKGROUND: Left ventricular (LV) ejection fraction (EF) during high dobutamine stress (HD) by real-time gated-SPECT myocardial perfusion imaging (MPI) on a cadmium-zinc-telluride (CZT) gamma camera was validated versus cardiac magnetic resonance imaging (CMR). METHODS AND RESULTS: After injecting 99mTc-tetrofosmin (320 MBq) in 50 patients (mean age 64 +/- 11 years), EF at rest and post-stress as well as relevant changes in EF at HD (ΔEF ≥ 5%) were assessed. CZT and CMR rest EF values yielded an excellent correlation and agreement (r = 0...
January 16, 2018: Journal of Nuclear Cardiology: Official Publication of the American Society of Nuclear Cardiology
Megan E Paciaroni, Yi Chen, Kyle P Lynch, Daniel R Guildenbecher
Conventional particle image velocimetry (PIV) configurations require a minimum of two optical access ports, inherently restricting the technique to a limited class of flows. Here, the development and application of a novel method of backscattered time-gated PIV requiring a single-optical-access port is described along with preliminary results. The light backscattered from a seeded flow is imaged over a narrow optical depth selected by an optical Kerr effect (OKE) time gate. The picosecond duration of the OKE time gate essentially replicates the width of the laser sheet of conventional PIV by limiting detected photons to a narrow time-of-flight within the flow...
January 15, 2018: Optics Letters
Nicholas R Lamoureux, Grant R Tomkinson, Benjamin J Peterson, John S Fitzgerald
The purpose of this study was to determine the importance of skating economy to fatigue during repeated high-intensity efforts of a simulated ice hockey shift. Forty-five collegiate and Junior A male ice hockey players (aged 18-24 years) performed a continuous graded exercise test using a skate treadmill. Breath-by-breath data for oxygen consumption (V[Combining Dot Above]O2) and respiratory exchange ratio were collected and used to derive energy expenditure (EE) averaged over the final 10 seconds of each stage...
January 5, 2018: Journal of Strength and Conditioning Research
Haihong He, Zhiwei Ye, Yi Xiao, Wei Yang, Xuhong Qian, Youjun Yang
Nitric oxide (NO) potentially plays a regulatory role in mitochondrial fusion and fission, which are vital to cell survival and implicated in health, disease, and aging. Molecular tools facilitating the study of the relationship between NO and mitochondrial dynamics are in need. We have recently developed a novel NO donor (NOD550). Upon photoactivation, NOD550 decomposes to release two NO molecules and a fluorophore. The NO release could be spatially mapped with subdiffraction resolution and with a temporal resolution of 10 s...
January 23, 2018: Analytical Chemistry
Yao Yao, Loruhama Delgado-Rivera, Hamid Samareh Afsari, Liang Yin, Gregory R J Thatcher, Terry W Moore, Lawrence W Miller
Hydrogen sulfide (H2S) is now recognized as an important gaseous transmitter that is involved in a variety of biological processes. Here, we report the design and synthesis of a luminescent lanthanide biosensor for H2S, LP2-Cu(II)-Ln(III), a heterobinuclear metal complex that uses Cu(II) decomplexation to control millisecond-scale-lifetime-Tb(III)- or Eu(III)-emission intensity. LP2-Cu(II)-Ln(III) responded rapidly, selectively, and with high sensitivity to aqueous H2S. The probe's potential for biological applications was verified by measuring the H2S generated by the slow-releasing chemical-sulfide-donor GYY4147, by cystathionine γ-lyase (CSE), and by Na2S-stimulated HeLa cells...
December 27, 2017: Inorganic Chemistry
Liping Wei, Wenrong Yan, Derek Ho
Fluorescence spectroscopy has become a prominent research tool with wide applications in medical diagnostics and bio-imaging. However, the realization of combined high-performance, portable, and low-cost spectroscopic sensors still remains a challenge, which has limited the technique to the laboratories. A fluorescence lifetime measurement seeks to obtain the characteristic lifetime from the fluorescence decay profile. Time-correlated single photon counting (TCSPC) and time-gated techniques are two key variations of time-resolved measurements...
December 4, 2017: Sensors
Min Woo Kim, Wenjing Wang, Mateo I Sanchez, Robert Coukos, Mark von Zastrow, Alice Y Ting
Transcriptional assays, such as yeast two-hybrid and TANGO, that convert transient protein-protein interactions (PPIs) into stable expression of transgenes are powerful tools for PPI discovery, screens, and analysis of cell populations. However, such assays often have high background and lose information about PPI dynamics. We have developed SPARK (Specific Protein Association tool giving transcriptional Readout with rapid Kinetics), in which proteolytic release of a membrane-tethered transcription factor (TF) requires both a PPI to deliver a protease proximal to its cleavage peptide and blue light to uncage the cleavage site...
November 30, 2017: ELife
Yong Shin Kim, Yuanyuan Yang, Charles S Henry
Numerous fabrication methods have been reported for microfluidic paper-based analytical devices (μPADs) using barrier materials ranging from photoresist to wax. While these methods have been used with wide success, consistently producing small, high-resolution features using materials and methods that are compatible with solvents and surfactants remains a challenge. Two new methods are presented here for generating μPADs with well-defined, high-resolution structures compatible with solvents and surfactant-containing solutions by partially or fully fusing paper with Parafilm® followed by cutting with a CO2 laser cutter...
February 2018: Sensors and Actuators. B, Chemical
Anne Kathrine R Junker, Thomas Just Sørensen
The influence of an electron donating substituent on the photophysical properties of 1-azathioxanthone dyes has been investigated using optical spectroscopy and theoretical models. The motivation behind the study is based on the fact that thioxanthones are efficient triplet sensitizers, and thus promising sensitizers for lanthanide centered emission. By adding an aza group to one of the phenyl ring systems, direct coordination to a lanthanide center becomes possible, which makes azathoixanthones great candidates as antenna chromophores in lanthanide(III) based dyes...
November 21, 2017: Methods and Applications in Fluorescence
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