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"Timing gate"

Joseph D Kimball, Badri Maliwal, Sangram L Raut, Hung Doan, Zhangatay Nurekeyev, Ignacy Gryczynski, Zygmunt Gryczynski
Fluorescence signal enhancement induced by the binding of intercalators to DNA has been broadly utilized in various DNA detection methods. In most instances the increase in fluorescence intensity is associated with a concomitant increase of fluorescence lifetime. This increase of the fluorescence lifetime presents an additional opportunity to increase detection sensitivity. In this paper, we present a new approach to significantly enhance the sensitivity in detecting minute DNA concentrations. The approach is based on simultaneous use of time-gated detection and multi-pulse pumping...
May 18, 2018: Analyst
Yasufumi Fuchi, Takashi Fukuda, Shigeki Sasaki
The 9-hydroxy-1,3-diazaphenoxazine-2-one unit was conjugated with the Eu3+ -cyclen complex through a linker. This diazaphenoxazine group was expected as an antenna unit for the excitation of europium ion, and a selective recognition site for 8-oxo-dGTP base. Among the synthesized three derivatives, the highest fluorescence emission was obtained by the complex constructed of an ethylene linker and the cyclen unit with three N,N-dimethylacetamide groups. The Eu3+ -cyclen complex exhibited a selective response to the 8-oxo-dGTP in aqueous media by a time-resolved fluorescence assay...
April 27, 2018: Bioorganic & Medicinal Chemistry
Chih-Hao Cheng, Chih-Ying Chen, Jun-Da Chen, Da-Kung Pan, Kai-Ting Ting, Fan-Yi Lin
We develop an unprecedented 3D pulsed chaos lidar system for potential intelligent machinery applications. Benefited from the random nature of the chaos, conventional CW chaos lidars already possess excellent anti-jamming and anti-interference capabilities and have no range ambiguity. In our system, we further employ self-homodyning and time gating to generate a pulsed homodyned chaos to boost the energy-utilization efficiency. Compared to the original chaos, we show that the pulsed homodyned chaos improves the detection SNR by more than 20 dB...
April 30, 2018: Optics Express
S Konugolu Venkata Sekar, S Mosca, S Tannert, G Valentini, F Martelli, T Binzoni, Y Prokazov, E Turbin, W Zuschratter, R Erdmann, A Pifferi
We present a time domain diffuse Raman spectrometer for depth probing of highly scattering media. The system is based on, to the best of our knowledge, a novel time-correlated single-photon counting (TCSPC) camera that simultaneously acquires both spectral and temporal information of Raman photons. A dedicated non-contact probe was built, and time domain Raman measurements were performed on a tissue mimicking bilayer phantom. The fluorescence contamination of the Raman signal was eliminated by early time gating (0-212 ps) the Raman photons...
May 1, 2018: Optics Letters
Dirk H Ortgies, Meiling Tan, Erving C Ximendes, Blanca Del Rosal, Jie Hu, Lei Xu, Xindong Wang, Emma Martin Rodriguez, Carlos Jacinto, Nuria Fernandez, Guanying Chen, Daniel Jaque
Advanced diagnostic procedures are required to satisfy the continuously increasing demands of modern biomedicine while also addressing the need for cost reduction in public health systems. The development of infrared luminescence-based techniques for in vivo imaging is emerging as a reliable alternative to traditional imaging techniques, applicable with simpler and more cost-effective apparatus. In order to further improve the information provided by in vivo luminescence images, the design and fabrication of enhanced infrared-luminescent contrast agents is required...
April 26, 2018: ACS Nano
Svetlana Shkolyar, Evan J Eshelman, Jack D Farmer, David Hamilton, Michael G Daly, Cody Youngbull
The Mars 2020 mission will analyze samples in situ and identify any that could have preserved biosignatures in ancient habitable environments for later return to Earth. Highest priority targeted samples include aqueously formed sedimentary lithologies. On Earth, such lithologies can contain fossil biosignatures as aromatic carbon (kerogen). In this study, we analyzed nonextracted kerogen in a diverse suite of natural, complex samples using colocated UV excitation (266 nm) time-gated (UV-TG) Raman and laser-induced fluorescence spectroscopies...
April 6, 2018: Astrobiology
C Li, S Liu, W Wang, W Liu, C Kuang, X Liu
Stimulated emission depletion (STED) microscopy is a useful tool in investigation for super-resolution realm. By silencing the peripheral fluorophores of the excited spot, leaving only the very centre zone vigorous for fluorescence, the effective point spread function (PSF) could be immensely squeezed and subcellular structures, such as organelles, become discernable. Nevertheless, because of the low cross-section of stimulated emission and the short fluorescence lifetime, the depletion power density has to be extremely higher than the excitation power density and molecules are exposed in high risk of photobleaching...
March 30, 2018: Journal of Microscopy
Susana F Silva, José Paulo Domingues, António Miguel Morgado
Time-gated fluorescence lifetime imaging microscopy (FLIM) is a powerful technique to assess the biochemistry of cells and tissues. When applied to living thick samples, it is hampered by the lack of optical sectioning and the need of acquiring many images for an accurate measurement of fluorescence lifetimes. Here, we report on the use of processing techniques to overcome these limitations, minimizing the acquisition time, while providing optical sectioning. We evaluated the application of the HiLo and the rapid lifetime determination (RLD) techniques for accurate measurement of fluorescence lifetimes with optical sectioning...
2018: Journal of Healthcare Engineering
Petr Bruza, Sarah L Gollub, Jacqueline M Andreozzi, Irwin I Tendler, Benjamin B Williams, Lesley A Jarvis, David J Gladstone, Brian W Pogue
To measure surface dose by remote time-gated imaging of plastic scintillators.
 Methods: A novel technique for time-gated, intensified camera imaging of scintillator emission was demonstrated, and key parameters influencing the signal were analyzed, including distance, angle and thickness. A set of scintillator samples was calibrated by using thermo-luminescence detector response as reference. Examples of use in total skin electron therapy are described.
 Results: The data showed excellent room light rejection (signal-to-noise ratio of scintillation SNR ≈ 470), ideal scintillation dose response linearity, and 2% dose rate error...
March 28, 2018: Physics in Medicine and Biology
Ethan Phillip M LaRochelle, Jennifer R Shell, Jason R Gunn, Scott C Davis, Brian W Pogue
During external beam radiotherapy (EBRT), in vivo Cherenkov optical emissions can be used as a dosimetry tool or to excite luminescence, termed Cherenkov-excited luminescence (CEL) with microsecond-level time-gated cameras. The goal of this work was to develop a complete theoretical foundation for the detectable signal strength, in order to provide guidance on optimization of the limits of detection and how to optimize near real time imaging. The key parameters affecting photon production, propagation and detection were considered and experimental validation with both tissue phantoms and a murine model are shown...
March 20, 2018: Physics in Medicine and Biology
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 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...
April 3, 2018: Analytical Chemistry
M Cardoso Dos Santos, J Goetz, H Bartenlian, K-L Wong, L J Charbonnière, N Hildebrandt
Fluorescent nanoparticles (NPs) have become irreplaceable tools for advanced cellular and subcellular 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. The 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...
April 18, 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 large-scale 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 wide-scale time-gated luminescent (TGL) monitoring of metal ions covering nearly the entire periodic table in a cost-effective fashion...
March 6, 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 H2 S is key toward understanding the physiological and pathological functions of this gasotransmitter in live organisms. A ruthenium(II)-complex-based luminescence probe, Ru-MDB (MDB: 4'-methyl-[2,2'-bipyridine]-4-yl)methyl 2-((2,4-dinitrophenyl)thio)benzoate), was developed by introducing a new H2 S responsive masking moiety to a red-emitting RuII luminophore. Cleavage of this masking group by a H2 S-triggered reaction leads to a luminescence "off-on" response...
April 3, 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 28, 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...
March 2018: Advanced Materials
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