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"Timing gate"

Gregory Roe, Joshua Darrall-Jones, Christopher Black, William Shaw, Kevin Till, Ben Jones
PURPOSE: The purpose of this study was to investigate the validity of timing gates and 10 Hz GPS units (Catapult Optimeye S5) against a criterion measure (50 Hz radar gun) for assessing maximum sprint velocity (Vmax). METHODS: Nine male professional rugby union players performed three maximal 40 m sprints with three minutes rest between each effort with Vmax assessed simultaneously via timing gates, 10 Hz GPSOpen (Openfield software), GPSSprint (Sprint software) and radar gun...
October 13, 2016: International Journal of Sports Physiology and Performance
Yao Yao, Chen Kong, Liang Yin, Atul D Jain, Kiira Ratia, Gregory R Thatcher, Terry W Moore, Tom Driver, Lawrence W Miller
Herein, we report the design, synthesis and characterization of a lanthanide(III) complex-based probe for the time-gated luminescence detection of hydrogen sulfide (H₂S) in aqueous media. The probe's unique sensing mechanism relies on the selective reduction of azide to amine by sulfide, followed by intramolecular cyclization to form a quinolinone. The quinolinone is a sensitizer that absorbs near-UV light and transfers excitation energy to coordinated Tb(III) or Eu(III) ions to trigger a strong "turn-on" luminescence response with ms-scale lifetimes characteristic of lanthanide complexes...
October 12, 2016: Chemistry: a European Journal
Blanca Del Rosal, Dirk H Ortgies, Nuria Fernández, Francisco Sanz-Rodríguez, Daniel Jaque, Emma Martín Rodríguez
The always present and undesired contribution of autofluorescence is here completely avoided by combining a simple time gating technology with long lifetime neodymium doped infrared-emitting nanoparticles.
October 6, 2016: Advanced Materials
Ali Mohamadi, Lawrence W Miller
The synthesis, photophysical properties, and kinetic stability of a series of water-soluble, highly emissive Tb(III) and Eu(III) complexes featuring triethylenetetraamine hexaacetic acid (TTHA) and cyclohexyl triethylenetetraamine hexaacetic acid (cyTTHA) chelator scaffolds and carbostyril sensitizers are reported. The unique and modular design of the chelators gives rise to striking quantum yields of emission in aqueous solutions (up to 54%) as well as the characteristic lanthanides' photophysical properties (long excited-state lifetimes, large effective Stokes shifts, and narrow emission peaks)...
October 3, 2016: Bioconjugate Chemistry
Erin Finley, Angelica Cobb, Anna Duke, Andrew Paterson, Jakoah Brgoch
Inorganic persistent luminescent phosphors are an excellent class of optical reporters for enabling sensitive point-of-care diagnostics, particularly with smartphone-based biosensing devices in testing formats such as the lateral flow assay (LFA). Here, the development of persistent phosphors for this application is focused on the solid solution (Sr1-δBaδ)2MgSi2O7:Eu(2+),Dy(3+) (δ = 0, 0.125, 0.25, 0.375), which is prepared using a high-temperature solid-state reaction as confirmed by synchrotron X-ray powder diffraction...
October 12, 2016: ACS Applied Materials & Interfaces
Alina Theisen, Bin Yan, Jeffery M Brown, Michael Morris, Bruno Bellina, Perdita E Barran
We demonstrate the capabilities of a laser-coupled ion mobility mass spectrometer for analysis of peptide sequence and structure showing ultraviolet photodissociation (UVPD) spectra of mass and mobility selected ions. A Synapt G2-S mass spectrometer has been modified to allow photointeraction of ions post the mobility cell. For this work, we have employed a single wavelength laser, which irradiates at 266 nm. We present the unique capabilities of this instrument and demonstrate several key features. Irradiation of luteinizing hormone releasing hormone (LHRH), growth hormone releasing hexapeptide (GHRP-6), and TrpCage (sequence NLYIQWLKDGGPSSGRPPPS) yields extensive b- and y-type fragmentation as well as a- and c-type ions...
October 3, 2016: Analytical Chemistry
Albert Redo-Sanchez, Barmak Heshmat, Alireza Aghasi, Salman Naqvi, Mingjie Zhang, Justin Romberg, Ramesh Raskar
Spatial resolution, spectral contrast and occlusion are three major bottlenecks for non-invasive inspection of complex samples with current imaging technologies. We exploit the sub-picosecond time resolution along with spectral resolution provided by terahertz time-domain spectroscopy to computationally extract occluding content from layers whose thicknesses are wavelength comparable. The method uses the statistics of the reflected terahertz electric field at subwavelength gaps to lock into each layer position and then uses a time-gated spectral kurtosis to tune to highest spectral contrast of the content on that specific layer...
2016: Nature Communications
Nima Sayyadi, Irene Justiniano, Russell E Connally, Run Zhang, Bingyang Shi, Liisa Kautto, Arun V Everest-Dass, Jingli Yuan, Bradley J Walsh, Dayong Jin, Robert D Willows, James A Piper, Nicolle H Packer
We describe the application of a synthetically developed tetradentate β-diketonate-europium chelate with high quantum yield (39%), for sensitive immunodetection of prostate cancer cells (DU145). MIL38 antibody, a mouse monoclonal antibody against Glypican 1, conjugated directly to the chelate via lysine residues, resulted in soluble (hydrophilic) and stable immunoconjugates. Indirect labeling of the antibody by a europium chelated secondary polyclonal antibody and a streptavidin/biotin pair was also performed...
October 4, 2016: Analytical Chemistry
Petr Fomin, Dmitry Zhelondz, Christian Kargel
For the production of high-quality parts from recycled plastics, a very high purity of the plastic waste to be recycled is mandatory. The incorporation of fluorescent tracers ("markers") into plastics during the manufacturing process helps overcome typical problems of non-tracer based optical classification methods. Despite the unique emission spectra of fluorescent markers, the classification becomes difficult when the host plastics exhibit (strong) autofluorescence that spectrally overlaps the marker fluorescence...
August 29, 2016: Applied Spectroscopy
Nathan R Gemmell, Aongus McCarthy, Michele M Kim, Israel Veilleux, Timothy C Zhu, Gerald S Buller, Brian C Wilson, Robert H Hadfield
This paper presents a novel compact fiberoptic based singlet oxygen near-infrared luminescence probe coupled to an InGaAs/InP single photon avalanche diode (SPAD) detector. Patterned time gating of the single-photon detector is used to limit unwanted dark counts and eliminate the strong photosensitizer luminescence background. Singlet oxygen luminescence detection at 1270 nm is confirmed through spectral filtering and lifetime fitting for Rose Bengal in water, and Photofrin in methanol as model photosensitizers...
July 25, 2016: Journal of Biophotonics
Xiangyou Liu, Gary B Braun, Haizheng Zhong, David J Hall, Wenlong Han, Mingde Qin, Chuanzhen Zhao, Meina Wang, Zhi-Gang She, Chuanbao Cao, Michael J Sailor, William B Stallcup, Erkki Ruoslahti, Kazuki N Sugahara
The rapid development of fluorescence imaging technologies requires concurrent improvements in the performance of fluorescent probes. Quantum dots have been extensively used as an imaging probe in various research areas because of their inherent advantages based on unique optical and electronic properties. However, their clinical translation has been limited by the potential toxicity especially from cadmium. Here, a versatile bioimaging probe is developed by using highly luminescent cadmium-free CuInSe2/ZnS core/shell quantum dots conjugated with CGKRK (Cys-Gly-Lys-Arg-Lys) tumor-targeting peptides...
January 13, 2016: Advanced Functional Materials
Mir Irfanullah, Navneet Bhardwaj, Arindam Chowdhury
Water dispersible citrate-capped LaF3:Eu(5%) nanocrystals (NCs) have been partially surface-functionalized by 1,10-phenanthroline (phen) via a ligand exchange method to produce novel water dispersed citrate/phen-capped LaF3:Eu(5%) NCs in which citrate ligands preserve the water dispersibility of the NCs and phen ligands act as sensitizers of surface Eu(3+)-dopant sites. The partial ligand exchange and the formation of water dispersed NCs have been monitored by (1)H NMR spectroscopy, as well as luminescence measurements at different time intervals during the reaction...
August 2, 2016: Dalton Transactions: An International Journal of Inorganic Chemistry
Shujuan Liu, Yangliu Zhang, Hua Liang, Zejing Chen, Ziyu Liu, Qiang Zhao
Time-resolved luminescence imaging of intracellular oxygen levels has been demonstrated based on long-lived phosphorescent signal. A phosphorescent dinuclear iridium(III) complex Ir1 has been designed and synthesized, which exhibits excellent optical properties, such as high quantum yields, large Stokes shift, high photostability and long emission lifetime. The phosphorescent intensity and lifetime of complex are very sensitive to oxygen levels. Thus, the application of Ir1 for monitoring intracellular oxygen levels has been realized successfully...
July 11, 2016: Optics Express
Sean P Kearney, Daniel R Guildenbecher
We apply ultrafast pure-rotational coherent anti-Stokes Raman scattering (CARS) for temperature and relative oxygen concentration measurements in the plume emanating from a burning, aluminized ammonium-perchlorate propellant strand. Combustion of these metal-based propellants is a particularly hostile environment for laser-based diagnostics, with intense background luminosity and scattering from hot metal particles as large as several hundred micrometers in diameter. CARS spectra that were previously obtained using nanosecond pulsed lasers in an aluminum-particle-seeded flame are examined and are determined to be severely impacted by nonresonant background, presumably as a result of the plasma formed by particulate-enhanced laser-induced breakdown...
June 20, 2016: Applied Optics
Hamid Samareh Afsari, Marcelina Cardoso Dos Santos, Stina Lindén, Ting Chen, Xue Qiu, Paul M P van Bergen En Henegouwen, Travis L Jennings, Kimihiro Susumu, Igor L Medintz, Niko Hildebrandt, Lawrence W Miller
Time-gated Förster resonance energy transfer (FRET) using the unique material combination of long-lifetime terbium complexes (Tb) and semiconductor quantum dots (QDs) provides many advantages for highly sensitive and multiplexed biosensing. Although time-gated detection can efficiently suppress sample autofluorescence and background fluorescence from directly excited FRET acceptors, Tb-to-QD FRET has rarely been exploited for biomolecular imaging. We demonstrate Tb-to-QD time-gated FRET nanoassemblies that can be applied for intra- and extracellular imaging...
June 2016: Science Advances
Anca Margineanu, Jia Jia Chan, Douglas J Kelly, Sean C Warren, Delphine Flatters, Sunil Kumar, Matilda Katan, Christopher W Dunsby, Paul M W French
We present a high content multiwell plate cell-based assay approach to quantify protein interactions directly in cells using Förster resonance energy transfer (FRET) read out by automated fluorescence lifetime imaging (FLIM). Automated FLIM is implemented using wide-field time-gated detection, typically requiring only 10 s per field of view (FOV). Averaging over biological, thermal and shot noise with 100's to 1000's of FOV enables unbiased quantitative analysis with high statistical power. Plotting average donor lifetime vs...
2016: Scientific Reports
Péter Boross, Gábor Széchenyi, András Pályi
Gate control of donor electrons near interfaces is a generic ingredient of donor-based quantum computing. Here, we address the question: how is the phonon-assisted qubit relaxation time T 1 affected as the electron is shuttled between the donor and the interface? We focus on the example of the 'flip-flop qubit' (Tosi et al arXiv:1509.08538v1), defined as a combination of the nuclear and electronic states of a phosphorus donor in silicon, promising fast electrical control and long dephasing times when the electron is halfway between the donor and the interface...
August 5, 2016: Nanotechnology
César M Meylan, Joshua Trewin, Kelly McKean
The aims of the current study were to examine the external validity of inertial based parameters (inertial movement analysis; IMA) to detect multi-planar explosive actions during maximal sprinting, change of direction (COD) and to further determine its reliability, set appropriate magnitude bands for match analysis and assess its variability during international women's soccer matches. Twenty U20 female soccer players, wearing GPS units with a built-in accelerometer, completed three trials of a 40-m sprint and a 20-m sprint with a change of direction to the right or left at 10-m...
June 13, 2016: International Journal of Sports Physiology and Performance
Ruilong Zhang, Shijiang Liu, Jianping Wang, Guangmei Han, Linlin Yang, Bianhua Liu, Guijian Guan, Zhongping Zhang
Luminescent chemosensors for hydrogen sulphide (H2S) are of great interest because of the close association of H2S with our health. However, current probes for H2S detection have problems such as low sensitivity/selectivity, poor aqueous-solubility or interference from background fluorescence. This study reports an ultrasensitive and time-gated "switch on" probe for detection of H2S, and its application in test paper for visualization of exhaled H2S. The complex probe is synthesized with a luminescent Tb(3+) centre and three ligands of azido (-N3) substituted pyridine-2,6-dicarboxylic acid, giving the probe high hydrophilicity and relatively fast reaction dynamics with H2S because there are three -N3 groups in each molecule...
August 2, 2016: Analyst
Nima Sayyadi, Andrew Care, Russell E Connally, Andrew C Try, Peter L Bergquist, Anwar Sunna
Luminescent lanthanide chelates have been used to label antibodies in time-gated luminescence (TGL) bioimaging. However, it is a challenging task to label directly an antibody with lanthanide-binding ligands and achieve control of the target ligand/protein ratios whilst ensuring that affinity and avidity of the antibody remain uncompromised. We report the development of a new indirect detection reagent to label antibodies with detectable luminescence that circumvents this problem by labelling available lysine residues in the linker portion of the recombinant fusion protein Linker-Protein G (LPG)...
2016: Scientific Reports
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