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Sample records for real-time fluorescence measurement

  1. Real-time quantitative fluorescence measurement of microscale cell culture analog systems

    NASA Astrophysics Data System (ADS)

    Oh, Taek-il; Kim, Donghyun; Tatosian, Daniel; Sung, Jong Hwan; Shuler, Michael

    2007-02-01

    A microscale cell culture analog (μCCA) is a cell-based lab-on-a-chip assay that, as an animal surrogate, is applied to pharmacological studies for toxicology tests. A μCCA typically comprises multiple chambers and microfluidics that connect the chambers, which represent animal organs and blood flow to mimic animal metabolism more realistically. A μCCA is expected to provide a tool for high-throughput drug discovery. Previously, a portable fluorescence detection system was investigated for a single μCCA device in real-time. In this study, we present a fluorescence-based imaging system that provides quantitative real-time data of the metabolic interactions in μCCAs with an emphasis on measuring multiple μCCA samples simultaneously for high-throughput screening. The detection system is based on discrete optics components, with a high-power LED and a charge-coupled device (CCD) camera as a light source and a detector, for monitoring cellular status on the chambers of each μCCA sample. Multiple samples are characterized mechanically on a motorized linear stage, which is fully-automated. Each μCCA sample has four chambers, where cell lines MES-SA/DX- 5, and MES-SA (tumor cells of human uterus) have been cultured. All cell-lines have been transfected to express the fusion protein H2B-GFP, which is a human histone protein fused at the amino terminus to EGFP. As a model cytotoxic drug, 10 μM doxorubicin (DOX) was used. Real-time quantitative data of the intensity loss of enhanced green fluorescent protein (EGFP) during cell death of target cells have been collected over several minutes to 40 hours. Design issues and improvements are also discussed.

  2. Real-Time Visualization of Tissue Surface Biochemical Features Derived From Fluorescence Lifetime Measurements.

    PubMed

    Gorpas, Dimitris; Ma, Dinglong; Bec, Julien; Yankelevich, Diego R; Marcu, Laura

    2016-08-01

    Fiber based fluorescence lifetime imaging has shown great potential for intraoperative diagnosis and guidance of surgical procedures. Here we describe a novel method addressing a significant challenge for the practical implementation of this technique, i.e., the real-time display of the quantified biochemical or functional tissue properties superimposed on the interrogated area. Specifically, an aiming beam (450 nm) generated by a continuous-wave laser beam was merged with the pulsed fluorescence excitation light in a single delivery/collection fiber and then imaged and segmented using a color-based algorithm. We demonstrate that this approach enables continuous delineation of the interrogated location and dynamic augmentation of the acquired frames with the corresponding fluorescence decay parameters. The method was evaluated on a fluorescence phantom and fresh tissue samples. Current results demonstrate that 34 frames per second can be achieved for augmenting videos of 640 × 512 pixels resolution. Also we show that the spatial resolution of the fluorescence lifetime map depends on the tissue optical properties, the scanning speed, and the frame rate. The dice similarity coefficient between the fluorescence phantom and the reconstructed maps was estimated to be as high as 93%. The reported method could become a valuable tool for augmenting the surgeon's field of view with diagnostic information derived from the analysis of fluorescence lifetime data in real-time using handheld, automated, or endoscopic scanning systems. Current method provides also a means for maintaining the tissue light exposure within safety limits. This study provides a framework for using an aiming beam with other point spectroscopy applications. PMID:26890641

  3. Real-time smart fluorescence sensor platform

    NASA Astrophysics Data System (ADS)

    Dickens, Jason E.; Vaughn, Mike S.; Taylor, Mervin; Ponstingl, Mike

    2011-06-01

    A novel compact LED array based light induced fluorescence (LIF) sensor has been developed for real-time in-line monitoring of intrinsic fluorophores in the solid and liquid state. The sensor is essential for on-the-spot, routine, and cost effective real-time analysis. The sensor is designed to provide real-time emission response along with various smart sensing parameters to ensure real-time measurement quality that is required for regulated GMP process monitoring applications. This work describes a LIF sensor tailored for solid-phase fluorometry. Fundamental figures of merit, excitation overexposure and smart sensing features required for modern process monitoring and control are discussed within the context of pharmaceutical solid-phase manufacturing and similar applications.

  4. Ambient measurements of biological aerosol particles near Killarney, Ireland: a comparison between real-time fluorescence and microscopy techniques

    NASA Astrophysics Data System (ADS)

    Healy, D. A.; Huffman, J. A.; O'Connor, D. J.; Pöhlker, C.; Pöschl, U.; Sodeau, J. R.

    2014-08-01

    Primary biological aerosol particles (PBAPs) can contribute significantly to the coarse particle burden in many environments. PBAPs can thus influence climate and precipitation systems as cloud nuclei and can spread disease to humans, animals, and plants. Measurement data and techniques for PBAPs in natural environments at high time- and size resolution are, however, sparse, and so large uncertainties remain in the role that biological particles play in the Earth system. In this study two commercial real-time fluorescence particle sensors and a Sporewatch single-stage particle impactor were operated continuously from 2 August to 2 September 2010 at a rural sampling location in Killarney National Park in southwestern Ireland. A cascade impactor was operated periodically to collect size-resolved particles during exemplary periods. Here we report the first ambient comparison of a waveband integrated bioaerosol sensor (WIBS-4) with a ultraviolet aerodynamic particle sizer (UV-APS) and also compare these real-time fluorescence techniques with results of fluorescence and optical microscopy of impacted samples. Both real-time instruments showed qualitatively similar behavior, with increased fluorescent bioparticle concentrations at night, when relative humidity was highest and temperature was lowest. The fluorescent particle number from the FL3 channel of the WIBS-4 and from the UV-APS were strongly correlated and dominated by a 3 μm mode in the particle size distribution. The WIBS FL2 channel exhibited particle modes at approx. 1 and 3 μm, and each was correlated with the concentration of fungal spores commonly observed in air samples collected at the site (ascospores, basidiospores, Ganoderma spp.). The WIBS FL1 channel exhibited variable multimodal distributions turning into a broad featureless single mode after averaging, and exhibited poor correlation with fungal spore concentrations, which may be due to the detection of bacterial and non-biological fluorescent

  5. Ambient measurements of biological aerosol particles near Killarney, Ireland: a comparison between real-time fluorescence and microscopy techniques

    NASA Astrophysics Data System (ADS)

    Healy, D. A.; Huffman, J. A.; O'Connor, D. J.; Pöhlker, C.; Pöschl, U.; Sodeau, J. R.

    2014-02-01

    Primary biological aerosol particles (PBAP) can contribute significantly to the coarse particle burden in many environments, may thus influence climate and precipitation systems as cloud nuclei, and can spread disease to humans, animals, and plants. Measurements of PBAP in natural environments taken at high time- and size- resolution are, however, sparse and so large uncertainties remain in the role that biological particles play in the Earth system. In this study two commercial real-time fluorescence particle sensors and a Sporewatch single-stage particle impactor were operated continuously from 2 August to 2 September 2010 at a rural sampling location in Killarney National Park in south western Ireland. A cascade impactor was operated periodically to collect size-resolved particles during exemplary periods. Here we report the first ambient comparison of the waveband integrated bioaerosol sensor (WIBS-4) with the ultraviolet aerodynamic particle sizer (UV-APS) and also compare these real-time fluorescence techniques with results of fluorescence and optical microscopy of impacted samples. Both real-time instruments showed qualitatively similar behaviour, with increased fluorescent bioparticle concentrations at night when relative humidity was highest and temperature was lowest. The fluorescent particle number from the FL3 channel of the WIBS-4 and from the UV-APS were strongly correlated and dominated by a 3 μm mode in the particle size distribution. The WIBS FL2 channel exhibited particle modes at approx. 1 and 3 μm, and each were correlated with the concentration of fungal spores commonly observed in air samples collected at the site (ascospores, basidiospores, Ganoderma spp.). The WIBS FL1 channel exhibited variable multi-modal distributions turning into a broad featureless single mode after averaging and exhibited poor correlation with fungal spore concentrations, which may be due to the detection of bacterial and non-biological fluorescent particles

  6. Aerosol-fluorescence spectrum analyzer: real-time measurement of emission spectra of airborne biological particles

    NASA Astrophysics Data System (ADS)

    Hill, Steven C.; Pinnick, Ronald G.; Nachman, Paul; Chen, Gang; Chang, Richard K.; Mayo, Michael W.; Fernandez, Gilbert L.

    1995-10-01

    We have assembled an aerosol-fluorescence spectrum analyzer (AFS), which can measure the fluorescence spectra and elastic scattering of airborne particles as they flow through a laser beam. The aerosols traverse a scattering cell where they are illuminated with intense (50 kW/cm 2) light inside the cavity of an argon-ion laser operating at 488 nm. This AFS can obtain fluorescence spectra of individual dye-doped polystyrene microspheres as small as 0.5 mu m in diameter. The spectra obtained from microspheres doped with pink and green-yellow dyes are clearly different. We have also detected the fluorescence spectra of airborne particles (although not single particles) made from various

  7. Real-time detection and characterization of individual flowing airborne biological particles: fluorescence spectra and elastic scattering measurements

    NASA Astrophysics Data System (ADS)

    Pan, Yongle; Holler, Stephen; Chang, Richard K.; Hill, Steven C.; Pinnick, Ronald G.; Niles, Stanley; Bottiger, Jerold R.; Bronk, Burt V.

    1999-11-01

    Real-time methods which is reagentless and could detect and partially characterize bioaerosols are of current interest. We present a technique for real-time measurement of UV-excited fluorescence spectra and two-dimensional angular optical scattering (TAOS) from individual flowing biological aerosol particles. The fluorescence spectra have been observed from more than 20 samples including Bacillus subtilis, Escherichia coli, Erwinia herbicola, allergens, dust, and smoke. The S/N and resolution of the spectra are sufficient for observing small lineshape differences among the same type of bioaerosol prepared under different conditions. The additional information from TAOS regarding particle size, shape, and granularity has the potential of aiding in distinguishing bacterial aerosols from other aerosols, such as diesel and cigarette smoke.

  8. Laser-induced fluorescence over optical fibers for real time in situ measurement of petroleum hydrocarbons in seawater

    NASA Astrophysics Data System (ADS)

    Lieberman, S. H.; Inman, S. M.; Theriault, G. A.

    1993-04-01

    A fiber optic-based fluorometer system is described that uses a pulsed laser to induce fluorescence and a time-gated linear photodiode array coupled to a spectrograph for rapid measurement of fluorescence emission spectra and fluorescence decay times. Data is presented from studies conducted in San Diego Bay where the system has been used for real-time in situ measurements of temporal and spatial variability of petroleum hydrocarbons in seawater. Results show that the optical fiber fluorometer system is capable of direct quantification of low level (parts-per-billion diesel fuel marine equivalent) concentrations of petroleum hydrocarbons. Analysis times for measurement of complete fluorescence emission spectra are fast (tens of milliseconds) and compare with the temporal response characteristics for temperature and conductivity sensors that are used for measuring standard physical hydrographic parameters. Results obtained with the fiber optic fluorometer system during a mapping study in San Diego Bay show good correlation with GC-MS analysis of total polycyclic aromatic hydrocarbons (PAHs) measured on discrete samples collected during the study.

  9. Tissue distribution and real-time fluorescence measurement of a tumor-targeted nanodevice by a two photon optical fiber fluorescence probe

    NASA Astrophysics Data System (ADS)

    Thomas, Thommey P.; Ye, Jing Yong; Yang, Chu-Sheng; Myaing, Monthiri; Majoros, Istvan J.; Kotlyar, Alina; Cao, Zhengyi; Norris, Theodore B.; Baker, James R., Jr.

    2006-02-01

    Real-time fluorescence measurement in deep tumors in live animals (or humans) by conventional methods has significant challenges. We have developed a two-photon optical fiber fluorescence (TPOFF) probe as a minimally invasive technique for quantifying fluorescence in solid tumors in live mice. Here we demonstrate TPOFF for real-time measurements of targeted drug delivery dynamics to tumors in live mice. 50-femtosecond laser pulses at 800 nm were coupled into a single mode optical fiber and delivered into the tumor through a 27-gauge needle. Fluorescence was collected back through the same fiber, filtered, and detected with photon counting. Biocompatible dendrimer-based nanoparticles were used for targeted delivery of fluorescent materials into tumors. Dendrimers with targeting agent folic acid and fluorescent reporter 6-TAMRA (G5-6T-FA) were synthesized. KB cell tumors expressing high levels of FA receptors were developed in SCID mice. We initially demonstrated the specific uptake of the targeted conjugates into tumor, kidney and liver, using the TPOFF probe. The tumor fluorescence was then taken in live mice at 30 min, 2 h and 24 h with the TPOFF probe. G5-6T-FA accumulated in the tumor with maximum mean levels reaching 673 +/- 67 nM at the 2 h time point. In contrast, the levels of a control, non-targeted conjugate (G5-6T) at 2 h reached a level of only 136 +/- 28 nM in tumors, and decrease quickly. This indicates that the TPOFF probe can be used as a minimally invasive detection system for quantifying the specific targeting of a fluorescent nanodevice on a real-time basis.

  10. Real-time method and apparatus for measuring the temperature of a fluorescing phosphor

    DOEpatents

    Britton, Jr., Charles L.; Beshears, David L.; Simpson, Marc L.; Cates, Michael R.; Allison, Steve W.

    1999-01-01

    A method for determining the temperature of a fluorescing phosphor is provided, together with an apparatus for performing the method. The apparatus includes a photodetector for detecting light emitted by a phosphor irradiated with an excitation pulse and for converting the detected light into an electrical signal. The apparatus further includes a differentiator for differentiating the electrical signal and a zero-crossing discrimination circuit that outputs a pulse signal having a pulse width corresponding to the time period between the start of the excitation pulse and the time when the differentiated electrical signal reaches zero. The width of the output pulse signal is proportional to the decay-time constant of the phosphor.

  11. Real-time fluorescence microscopy monitoring of porphyrin biodistribution

    NASA Astrophysics Data System (ADS)

    Kimel, Sol; Gottfried, Varda; Kunzi-Rapp, Karin; Akguen, Nermin; Schneckenburger, Herbert

    1996-01-01

    In vivo uptake of the natural porphyrins, uroporphyrin III (UP), coproporphyrin III (CP) and protoporphyrin IX (PP), was monitored by fluorescence microscopy. Experiments were performed using the chick chorioallantoic membrane (CAM) model, which allowed video documentation of fluorescence both in real time and after integration over a chosen time interval (usually 2 s). Sensitizers at a concentration of 50 (mu) M (100 (mu) L) were injected into a medium-sized vein (diameter approximately 40 micrometer) using an ultra-fine 10 micrometer diameter needle. Fluorescence images were quantitated by subtracting the fluorescence intensity of surrounding CAM tissue (Fmatrix) from the intravascular fluorescence intensity (Fintravascular), after transformation of the video frames into digital form. The differential fluorescence intensity, Fintravascular - Fmatrix, is a measure of the biodistribution. Real time measurements clearly showed that CP and UP fluorescence is associated with moving erythrocytes and not with endothelial cells of the vessel wall. Fluorescence intensity was monitored, up to 60 minutes after injection, by averaging the fluorescence over time intervals of 2 s and recording the integrated images. The fluorescence intensity reached its maximum in about 20 - 30 min after injection, presumably after monomerization inside erythrocyte membranes. The results are interpreted in terms of physical-chemical characteristics (e.g. hydrophilicity) and correlated with the photodynamically induced hemostasis in CAM blood vessels.

  12. Real-time measurement of dual-wavelength laser-induced fluorescence spectra of individual aerosol particles.

    PubMed

    Huang, Hermes C; Pan, Yong-Le; Hill, Steven C; Pinnick, Ronald G; Chang, Richard K

    2008-10-13

    We report the development of an in-situ aerosol detection system capable of rapidly measuring dual-wavelength laser-induced fluorescence spectra of single particles on the fly using a single spectrometer and a single 32-anode photomultiplier array. We demonstrate the capability of this system with both reference samples and outdoor air. We present spectra from separate excitation wavelengths from the same particle that demonstrate improved discrimination capability compared with only using one excitation wavelength. PMID:18852760

  13. Development of real time detector for fluorescent particles

    SciTech Connect

    Prevost, C.; Vendel, J.; Seigneur, A.

    1997-08-01

    Aerosols tagged by a fluorescent dye are a worthwhile tool within the framework of ventilation and filtration studies. The detection in real time of a specific particulate tracer allows characterization of ventilation behaviour such as air change rate, the determination of a good or bad mixing zone and transfer coefficient, or the determination of the decontamination factor for High Efficiency Particulate Air (HEPA) filters. Generally, these tests require specific aerosols in order to get rid of the atmospheric aerosol background. Until now the principle of fluorescent aerosol concentration measuring has only allowed an integral response with a time lag by means of sampling on filters and a fluorimetric analysis after specific conditioning of these filters. 5 refs., 13 figs.

  14. Real-time method and apparatus for measuring the decay-time constant of a fluorescing phosphor

    DOEpatents

    Britton, Jr., Charles L.; Beshears, David L.; Simpson, Marc L.; Cates, Michael R.; Allison, Steve W.

    1999-01-01

    A method for determining the decay-time constant of a fluorescing phosphor is provided, together with an apparatus for performing the method. The apparatus includes a photodetector for detecting light emitted by a phosphor irradiated with an excitation pulse and for converting the detected light into an electrical signal. The apparatus further includes a differentiator for differentiating the electrical signal and a zero-crossing discrimination circuit that outputs a pulse signal having a pulse width corresponding to the time period between the start of the excitation pulse and the time when the differentiated electrical signal reaches zero. The width of the output pulse signal is proportional to the decay-time constant of the phosphor.

  15. Hyd5 gene based analysis of cereals and malt for gushing-inducing Fusarium spp. by real-time LAMP using fluorescence and turbidity measurements.

    PubMed

    Denschlag, Carla; Vogel, Rudi F; Niessen, Ludwig

    2013-04-01

    The surface active class 2 hydrophobin Hyd5p (GenBank accession number DQ449530) has been identified as a causative agent for over foaming (gushing) of beer. In order to estimate the potential of brewing cereals and malt to induce gushing in beer we used a previously described set of primers to amplify a partial sequence of the hyd5 gene in Fusarium culmorum and closely related species in a real-time loop-mediated isothermal amplification assay. Real-time LAMP was optimized and performed on two different platforms using a turbidimeter and a fluorescence reader to monitor the reaction on line. Serial dilutions of purified target DNA were used to set up a calibration curve for quantitative estimation of DNA concentrations. Analysis of model barley samples prepared by mixing infected with non-infected material in different ratios demonstrated a positive correlation between the real-time LAMP results and respective infection levels. In order to investigate the performance of the newly established methods, samples of barley were analyzed for their gushing potential using the Hyd5 real-time LAMP assay and a reference in vitro test for gushing prediction (Modified Carlsberg Test, MCT) in parallel experiments. Results showed that the real-time LAMP assay was in accordance with the reference test in 50% of cases with both platforms used. It predicted a lower number of gushing-positive samples as compared to the current reference test. PMID:23454815

  16. A Measure of Real-Time Intelligence

    NASA Astrophysics Data System (ADS)

    Gavane, Vaibhav

    2013-03-01

    We propose a new measure of intelligence for general reinforcement learning agents, based on the notion that an agent's environment can change at any step of execution of the agent. That is, an agent is considered to be interacting with its environment in real-time. In this sense, the resulting intelligence measure is more general than the universal intelligence measure (Legg and Hutter, 2007) and the anytime universal intelligence test (Hernández-Orallo and Dowe, 2010). A major advantage of the measure is that an agent's computational complexity is factored into the measure in a natural manner. We show that there exist agents with intelligence arbitrarily close to the theoretical maximum, and that the intelligence of agents depends on their parallel processing capability. We thus believe that the measure can provide a better evaluation of agents and guidance for building practical agents with high intelligence.

  17. Fluorescent real-time monitoring of HIFU cardiac focal ablation

    NASA Astrophysics Data System (ADS)

    Qu, Fujian; Nikolski, Vladimir; Efimov, Igor; Deng, Cheri

    2001-05-01

    To study HIFU cardiac ablation, florescent imaging was used to monitor in real time the electrophysiology changes of cardiac tissues during focal HIFU ablation. We applied HIFU ablation of AV nodal and ventricular preparations of Langendorff-perfused rabbit heart while monitoring electrical activity in real-time. HIFU energy was applied to ablate the AV node and ventricular tissue of Langendorff-perfused rabbit hearts while monitoring electrical activity in real-time with fluorescent voltage-sensitive dye imaging and surface electrodes. HIFU was generated using a spherical piezoelectric ceramics transducer (diameter 42 mm, F-number 1.2) at 4.23 MHz. When HIFU was applied to ventricular epicardium fluorescent imaging it revealed gradual reduction of the plateau phase and amplitude of the action potential. Subsequently conduction block and cell death were observed at the site of ablation. In our study HIFU produced focal lesions of 0.2-0.8 mm for 10-60-s applications. When HIFU was applied to the AV node, fluorescent imaging and electrograms revealed the development of the AV block.

  18. Kinetic Measurement and Real Time Visualization of Somatic Reprogramming.

    PubMed

    Quintanilla, Rene H; Asprer, Joanna; Sylakowski, Kyle; Lakshmipathy, Uma

    2016-01-01

    Somatic reprogramming has enabled the conversion of adult cells to induced pluripotent stem cells (iPSC) from diverse genetic backgrounds and disease phenotypes. Recent advances have identified more efficient and safe methods for introduction of reprogramming factors. However, there are few tools to monitor and track the progression of reprogramming. Current methods for monitoring reprogramming rely on the qualitative inspection of morphology or staining with stem cell-specific dyes and antibodies. Tools to dissect the progression of iPSC generation can help better understand the process under different conditions from diverse cell sources. This study presents key approaches for kinetic measurement of reprogramming progression using flow cytometry as well as real-time monitoring via imaging. To measure the kinetics of reprogramming, flow analysis was performed at discrete time points using antibodies against positive and negative pluripotent stem cell markers. The combination of real-time visualization and flow analysis enables the quantitative study of reprogramming at different stages and provides a more accurate comparison of different systems and methods. Real-time, image-based analysis was used for the continuous monitoring of fibroblasts as they are reprogrammed in a feeder-free medium system. The kinetics of colony formation was measured based on confluence in the phase contrast or fluorescence channels after staining with live alkaline phosphatase dye or antibodies against SSEA4 or TRA-1-60. The results indicated that measurement of confluence provides semi-quantitative metrics to monitor the progression of reprogramming. PMID:27500543

  19. Continuous flow real-time PCR device using multi-channel fluorescence excitation and detection.

    PubMed

    Hatch, Andrew C; Ray, Tathagata; Lintecum, Kelly; Youngbull, Cody

    2014-02-01

    High throughput automation is greatly enhanced using techniques that employ conveyor belt strategies with un-interrupted streams of flow. We have developed a 'conveyor belt' analog for high throughput real-time quantitative Polymerase Chain Reaction (qPCR) using droplet emulsion technology. We developed a low power, portable device that employs LED and fiber optic fluorescence excitation in conjunction with a continuous flow thermal cycler to achieve multi-channel fluorescence detection for real-time fluorescence measurements. Continuously streaming fluid plugs or droplets pass through tubing wrapped around a two-temperature zone thermal block with each wrap of tubing fluorescently coupled to a 64-channel multi-anode PMT. This work demonstrates real-time qPCR of 0.1-10 μL droplets or fluid plugs over a range of 7 orders of magnitude concentration from 1 × 10(1) to 1 × 10(7). The real-time qPCR analysis allows dynamic range quantification as high as 1 × 10(7) copies per 10 μL reaction, with PCR efficiencies within the range of 90-110% based on serial dilution assays and a limit of detection of 10 copies per rxn. The combined functionality of continuous flow, low power thermal cycling, high throughput sample processing, and real-time qPCR improves the rates at which biological or environmental samples can be continuously sampled and analyzed. PMID:24297040

  20. High-power white LED-based system incorporating a CCD Offner imaging spectrometer for real-time fluorescence qPCR measurements

    NASA Astrophysics Data System (ADS)

    Alaruri, Sami D.

    2014-12-01

    An optical system for qPCR fluorescence measurements which incorporates high-power white LEDs, PMMA plastic lenses and an Offner multichannel (imaging) CCD-based spectrometer has been developed and validated. The optical system can detect twenty reaction vessels in an asynchronous manner and up to seven different fluorescent dyes (7 plex) at 1 nM dye concentrations in each of the reaction vessels. Furthermore, PCR curves obtained using the optical measurement system for a genomic deoxyribonucleic acid (DNA) template containing HEX and Texas Red fluorescent probes (fluorophores) are discussed. The spectral resolution, dynamic range and repeatability of the measurement system are < 15 nm, > 3 decades and < 1% CV, respectively.

  1. Dual-wavelength-excitation single-particle fluorescence spectrometer/particle sorter for real-time measurement of organic carbon and biological aerosols

    NASA Astrophysics Data System (ADS)

    Pan, Yong-Le; Pinnick, Ron G.; Hill, Steven C.; Huang, Hermes; Chang, Richard K.

    2008-10-01

    We report the development of a Single-Particle Fluorescence Spectrometer (SPFS) system capable of measuring two UV-laser excited fluorescence spectra from a single particle on-the-fly. The two dispersed fluorescence spectra are obtained from excitation by two lasers at different wavelengths (263 nm and 351 nm). The SPFS samples single particles with sizes primarily in the 1-10 μm range. The fluorescence spectra are recorded from 280 nm to 600 nm (in 20 channels) for 263 nm excitation and from 370 nm to 700 nm (in 22 channels) for 351 nm excitation. The elastic scattering (channel 4 and 9) is also recorded for sizing each particle. A time stamp for single particles is marked with a variable time interval resolution from 10 ms to 10 minutes. The SPFS employs a virtual-impactor concentrator to concentrate respirable-sized particles with a resulting (size-dependent) effective flow rate of around 100 liters/min. The SPFS can measure single-particle spectra at a maximum rate of 90,000/sec, although the highest rates we have experienced for the ambient are only several hundred/sec. When the SPFS is combined with an aerodynamic deflector (puffer) to sort particles according to their fluorescence spectral characteristics, the SPFS/puffer system can selectively deflect and collect an enriched sample of targeted particles (at rates limited by the puffer) of 1200 particles/sec, for further examination. In laboratory tests, aerosol particles with similar UV-LIF spectra (e.g. B. subtilis and E.coli) are puffed into the reservoir of a micro-fluidic cell, where fluorescent-labeled antibodies bind to them and were classified by their labeled fluorescence. Measurements of the background ambient aerosol with the SPFS system made at sites with different regional climate (Connecticut, Maryland, and New Mexico) were clustered (unstructured hierarchical analysis) into 8-10 groups, with over 90% of all the fluorescent particles contained within these clusters (threshold dot product=0

  2. Portable real-time fluorescence cytometry of microscale cell culture analog devices

    NASA Astrophysics Data System (ADS)

    Kim, Donghyun; Tatosian, Daniel A.; Shuler, Michael L.

    2006-02-01

    A portable fluorescence cytometric system that provides a modular platform for quantitative real-time image measurements has been used to explore the applicability to investigating cellular events on multiple time scales. For a short time scale, we investigated the real-time dynamics of uptake of daunorubicin, a chemotherapeutic agent, in cultured mouse L-cells in a micro cell culture analog compartment using the fluorescent cytometric system. The green fluorescent protein (GFP) expression to monitor induction of pre-specified genes, which occurs on a much longer time scale, has also been measured. Here GFP fluorescence from a doxycycline inducible promoter in a mouse L-cell line was determined. Additionally, a system based on inexpensive LEDs showed performance comparable to a broadband light source based system and reduced photobleaching compared to microscopic examination.

  3. Real-time computation of subdiffraction-resolution fluorescence images.

    PubMed

    Wolter, S; Schüttpelz, M; Tscherepanow, M; VAN DE Linde, S; Heilemann, M; Sauer, M

    2010-01-01

    In the recent past, single-molecule based localization or photoswitching microscopy methods such as stochastic optical reconstruction microscopy (STORM) or photoactivated localization microscopy (PALM) have been successfully implemented for subdiffraction-resolution fluorescence imaging. However, the computational effort needed to localize numerous fluorophores is tremendous, causing long data processing times and thereby limiting the applicability of the technique. Here we present a new computational scheme for data processing consisting of noise reduction, detection of likely fluorophore positions, high-precision fluorophore localization and subsequent visualization of found fluorophore positions in a super-resolution image. We present and benchmark different algorithms for noise reduction and demonstrate the use of non-maximum suppression to quickly find likely fluorophore positions in high depth and very noisy images. The algorithm is evaluated and compared in terms of speed, accuracy and robustness by means of simulated data. On real biological samples, we find that real-time data processing is possible and that super-resolution imaging with organic fluorophores of cellular structures with approximately 20 nm optical resolution can be completed in less than 10 s. PMID:20055915

  4. Real-time point-of-care measurement of impaired renal function in a rat acute injury model employing exogenous fluorescent tracer agents

    NASA Astrophysics Data System (ADS)

    Dorshow, Richard B.; Fitch, Richard M.; Galen, Karen P.; Wojdyla, Jolette K.; Poreddy, Amruta R.; Freskos, John N.; Rajagopalan, Raghavan; Shieh, Jeng-Jong; Demirjian, Sevag G.

    2013-02-01

    Renal function assessment is needed for the detection of acute kidney injury and chronic kidney disease. Glomerular filtration rate (GFR) is now widely accepted as the best indicator of renal function, and current clinical guidelines advocate its use in the staging of kidney disease. The optimum measure of GFR is by the use of exogenous tracer agents. However current clinically employed agents lack sensitivity or are cumbersome to use. An exogenous GFR fluorescent tracer agent, whose elimination rate could be monitored noninvasively through skin would provide a substantial improvement over currently available methods. We developed a series of novel aminopyrazine analogs for use as exogenous fluorescent GFR tracer agents that emit light in the visible region for monitoring GFR noninvasively over skin. In rats, these compounds are eliminated by the kidney with urine recovery greater than 90% of injected dose, are not broken down or metabolized in vivo, are not secreted by the renal tubules, and have clearance values similar to a GFR reference compound, iothalamate. In addition, biological half-life of these compounds measured in rats by noninvasive optical methods correlated with plasma derived methods. In this study, we show that this noninvasive methodology with our novel fluorescent tracer agents can detect impaired renal function. A 5/6th nephrectomy rat model is employed.

  5. Severe storms measurement system real time data processing and displays

    NASA Technical Reports Server (NTRS)

    Jeffreys, H. B.

    1980-01-01

    The objectives of the system are to provide the system operator with real time system performance check and to provide data recording of all SSMS data. Meteorologists are provided with real time indication of meteorological data measurements including aid for directing flight profiles in real time and aid for directing SSMS operations. A day-to-day feedback is provided to meteorologists, system operators, and flight crews for flight planning on subsequent flight tests days.

  6. Superhilac real-time velocity measurements

    SciTech Connect

    Feinberg, B.; Meaney, D.; Thatcher, R.; Timossi, C.

    1987-03-01

    Phase probes have been placed in several external beam lines at the LBL heavy ion linear accelerator (SuperHILAC) to provide non-destructive velocity measurements independent of the ion being accelerated. The existing system has been improved to provide the following features: a display refresh rate better than twice per second, a sensitive pseudo-correlation technique to pick out the signal from the noise, simultaneous measurements of up to four ion velocities when more than one beam is being accelerated, and a touch-screen operator interface. These improvements allow the system to be used as a routine tuning aid and beam velocity monitor.

  7. Real-time Measurements of Biological Aerosol Particles in Clouds

    NASA Astrophysics Data System (ADS)

    Twohy, C. H.; McMeeking, G. R.; DeMott, P. J.; Toohey, D. W.; Kok, G.; McCluskey, C.; Hill, T. C.

    2013-12-01

    Some types of biological particles are known to efficiently nucleate ice at relatively warm temperatures in the atmosphere, with the potential to influence cloud microphysical properties and climate. However, the prevalence (or lack thereof) of these particle types in different parts of the atmosphere and in clouds is a matter of debate. Current techniques are mostly limited to near-ground sampling or to limited aircraft sampling with complex instrumentation. Many types of biological particles fluoresce when exposed to ultraviolet light, and the Wideband Integrated Bioaerosol Sensor (WIBS-4A) takes advantage of this characteristic to perform real-time measurements of biological particles. During the IDEAS-2013 test campaign based in Colorado (USA), the WIBS-4A was flown behind a counterflow virtual impactor (CVI) to measure concentrations of biological particles in clouds of different types, temperatures, and altitudes. Preliminary results from this first-ever combination of instruments on the high-performance Gulfstream-V research aircraft will be presented. Concentrations of fluorescent particles measured by the WIBS will also be related to ice nuclei concentrations and properties of particles collected simultaneously on filters.

  8. Results of the first-in-human clinical trial for MB-102, a novel fluorescent tracer agent for real-time measurement of glomerular filtration rate

    NASA Astrophysics Data System (ADS)

    Dorshow, Richard B.; Debreczeny, Martin P.; Dowling, Thomas C.

    2015-03-01

    The fluorescent tracer agent 2,5-bis[N-(1-carboxy-2-hydroxy)]carbamoyl-3,6-diaminopyrazine, designated MB-102, has been developed with properties and attributes necessary for use as a direct measure of glomerular filtration rate (GFR). Comparison to known standard exogenous GFR agents in animal models has demonstrated an excellent correlation. A clinical trial to demonstrate this same correlation in humans is in progress. This clinical trial is the first in a series of trials necessary to obtain regulatory clearance from the FDA. We report herein the comparison of plasma pharmacokinetics between MB-102 and the known standard exogenous GFR agent Iohexol in healthy subjects with normal renal function. Post simultaneous administration of both agents, blood samples over a period of 12 hours were collected from each subject to assess pharmacokinetic parameters including GFR. Urine samples were collected over this same period to assess percent injected dose recovered in the urine. Results indicate MB-102 is a GFR agent in humans from the comparison to the standard agent.

  9. Characterization and quantification of intact 26S proteasome proteins by real-time measurement of intrinsic fluorescence prior to top-down mass spectrometry.

    PubMed

    Russell, Jason D; Scalf, Mark; Book, Adam J; Ladror, Daniel T; Vierstra, Richard D; Smith, Lloyd M; Coon, Joshua J

    2013-01-01

    Quantification of gas-phase intact protein ions by mass spectrometry (MS) is impeded by highly-variable ionization, ion transmission, and ion detection efficiencies. Therefore, quantification of proteins using MS-associated techniques is almost exclusively done after proteolysis where peptides serve as proxies for estimating protein abundance. Advances in instrumentation, protein separations, and informatics have made large-scale sequencing of intact proteins using top-down proteomics accessible to the proteomics community; yet quantification of proteins using a top-down workflow has largely been unaddressed. Here we describe a label-free approach to determine the abundance of intact proteins separated by nanoflow liquid chromatography prior to MS analysis by using solution-phase measurements of ultraviolet light-induced intrinsic fluorescence (UV-IF). UV-IF is measured directly at the electrospray interface just prior to the capillary exit where proteins containing at least one tryptophan residue are readily detected. UV-IF quantification was demonstrated using commercially available protein standards and provided more accurate and precise protein quantification than MS ion current. We evaluated the parallel use of UV-IF and top-down tandem MS for quantification and identification of protein subunits and associated proteins from an affinity-purified 26S proteasome sample from Arabidopsis thaliana. We identified 26 unique proteins and quantified 13 tryptophan-containing species. Our analyses discovered previously unidentified N-terminal processing of the β6 (PBF1) and β7 (PBG1) subunit - such processing of PBG1 may generate a heretofore unknown additional protease active site upon cleavage. In addition, our approach permitted the unambiguous identification and quantification both isoforms of the proteasome-associated protein DSS1. PMID:23536786

  10. Estimating correlation for a real-time measure of connectivity.

    PubMed

    Arunkumar, Akhil; Panday, Ashish; Joshi, Bharat; Ravindran, Arun; Zaveri, Hitten P

    2012-01-01

    There has recently been considerable interest in connectivity analysis of fMRI and scalp and intracranial EEG time-series. The computational requirements of the pair-wise correlation (PWC), the core time-series measure used to estimate connectivity, presents a challenge to the real-time estimation of the PWC between all pairs of multiple time-series. We describe a parallel algorithm for computing PWC in real-time for streaming data from multiple channels. The algorithm was implemented on the Intel Xeon™ and IBM Cell Broadband Engine™ platforms. We evaluated time to estimate correlation for signals recorded with different acquisition parameters as a comparison to real-time constraints. We demonstrate that the execution time of these efficient implementations meet real-time constraints in most instances. PMID:23367098

  11. Following the dyeing of wool in real time using fluorescence microscopy

    NASA Astrophysics Data System (ADS)

    Bradley, Grant; Collins, Stephen; Davidson, R. Stephen

    1996-06-01

    The novel design of a heated stage (miniature dye bath) for use with an inverted fluorescence microscope is described. The heated stage allows investigation of wool dyeings to be followed in situ in real time. The photometer attachment of the microscope allows for quantitative analysis. The progress of the dyeing of wool with a fluorescent whitening agent and a fluorescent dye have been monitored in real time.

  12. Real-time measurement of mental workload: A feasibility study

    NASA Technical Reports Server (NTRS)

    Kramer, Arthur; Humphrey, Darryl; Sirevaag, Erik; Mecklinger, Axel

    1990-01-01

    The primary goal of the study was to explore the utility of event-related brain potentials (ERP) as real-time measures of workload. To this end, subjects performed two different tasks both separately and together. One task required that subjects monitor a bank of constantly changing gauges and detect critical deviations. Difficulty was varied by changing the predictability of the gauges. The second task was mental arithmetic. Difficulty was varied by requiring subjects to perform operations on either two or three columns of numbers. Two conditions that could easily be distinguished on the basis of performance measures were selected for the real-time evaluation of ERPs. A bootstrapping approach was adopted in which one thousand samples of n trials (n = 1, 3, 5 ...65) were classified using several measures of P300 and Slow Wave amplitude. Classification accuracies of 85 percent were achieved with 25 trials. Results are discussed in terms of potential enhancements for real-time recording.

  13. Real-time Fluorescence Image-Guided Oncologic Surgery

    PubMed Central

    Mondal, Suman B.; Gao, Shengkui; Zhu, Nan; Liang, Rongguang; Gruev, Viktor; Achilefu, Samuel

    2014-01-01

    Medical imaging plays a critical role in cancer diagnosis and planning. Many of these patients rely on surgical intervention for curative outcomes. This requires a careful identification of the primary and microscopic tumors, and the complete removal of cancer. Although there have been efforts to adapt traditional imaging modalities for intraoperative image guidance, they suffer from several constraints such as large hardware footprint, high operation cost, and disruption of the surgical workflow. Because of the ease of image acquisition, relatively low cost devices and intuitive operation, optical imaging methods have received tremendous interests for use in real-time image-guided surgery. To improve imaging depth under low interference by tissue autofluorescence, many of these applications utilize light in the near-infra red (NIR) wavelengths, which is invisible to human eyes. With the availability of a wide selection of tumor-avid contrast agents, advancements in imaging sensors, electronic and optical designs, surgeons are able to combine different attributes of NIR optical imaging techniques to improve treatment outcomes. The emergence of diverse commercial and experimental image guidance systems, which are in various stages of clinical translation, attests to the potential high impact of intraoperative optical imaging methods to improve speed of oncologic surgery with high accuracy and minimal margin positivity. PMID:25287689

  14. Real-time quantification of fatty acid uptake using a novel fluorescence assay.

    PubMed

    Liao, Jinfang; Sportsman, Richard; Harris, Jeff; Stahl, Andreas

    2005-03-01

    Uptake of nonesterified long-chain fatty acids (LCFAs) into many cell types and organs such as liver, heart, intestine, and skeletal muscle occurs primarily through a saturable, protein-mediated mechanism. Membrane proteins that increase the uptake of LCFAs, such as FAT/CD36 and fatty acid transport proteins, represent significant therapeutic targets for the treatment of metabolic disorders, including type 2 diabetes. However, currently available methods for the quantification of LCFA uptake neither allow for real-time measurements of uptake kinetics nor are ideally suited for the development of LCFA uptake inhibitors in high-throughput screens. To address both problems, we developed a LCFA uptake assay using a fluorescently labeled fatty acid and a nontoxic cell-impermeable quenching agent that allows fatty acid transport to be measured in real time using fluorescence plate readers or standard fluorescence microscopy. With this assay, we faithfully reproduced known differentiation- and hormone-induced changes in LCFA uptake by 3T3-L1 cells and determined LCFA uptake kinetics with previously unobtainable temporal resolution. Applications of this novel assay should facilitate new insights into the biology of fatty acid uptake and provide new means for obesity-related drug discovery. PMID:15547301

  15. Real-time structured light intraoral 3D measurement pipeline

    NASA Astrophysics Data System (ADS)

    Gheorghe, Radu; Tchouprakov, Andrei; Sokolov, Roman

    2013-02-01

    Computer aided design and manufacturing (CAD/CAM) is increasingly becoming a standard feature and service provided to patients in dentist offices and denture manufacturing laboratories. Although the quality of the tools and data has slowly improved in the last years, due to various surface measurement challenges, practical, accurate, invivo, real-time 3D high quality data acquisition and processing still needs improving. Advances in GPU computational power have allowed for achieving near real-time 3D intraoral in-vivo scanning of patient's teeth. We explore in this paper, from a real-time perspective, a hardware-software-GPU solution that addresses all the requirements mentioned before. Moreover we exemplify and quantify the hard and soft deadlines required by such a system and illustrate how they are supported in our implementation.

  16. Real-time fluorescence imaging with 20 nm axial resolution

    PubMed Central

    Stabley, Daniel R.; Oh, Thomas; Simon, Sanford M.; Mattheyses, Alexa L.; Salaita, Khalid

    2015-01-01

    Measuring the nanoscale organization of protein structures near the plasma membrane of live cells is challenging, especially when the structure is dynamic. Here we present the development of a two-wavelength total internal reflection fluorescence method capable of real-time imaging of cellular structure height with nanometre resolution. The method employs a protein of interest tagged with two different fluorophores and imaged to obtain the ratio of emission in the two channels. We use this approach to visualize the nanoscale organization of microtubules and endocytosis of the epidermal growth factor receptor. PMID:26392382

  17. Selection of fluorescent DNA dyes for real-time LAMP with portable and simple optics.

    PubMed

    Seyrig, Gregoire; Stedtfeld, Robert D; Tourlousse, Dieter M; Ahmad, Farhan; Towery, Keara; Cupples, Alison M; Tiedje, James M; Hashsham, Syed A

    2015-12-01

    Loop-mediated isothermal amplification (LAMP) is increasingly used for point-of-care nucleic acid based diagnostics. LAMP can be monitored in real-time by measuring the increase in fluorescence of DNA binding dyes. However, there is little information comparing the effect of various fluorescent dyes on signal to noise ratio (SNR) or threshold time (Tt). This information is critical for implementation with field deployable diagnostic tools that require small, low power consumption, robust, and inexpensive optical components with reagent saving low volume reactions. In this study, SNR and Tt during real-time LAMP was evaluated with eleven fluorescent dyes. Of all dyes tested, SYTO-82, SYTO-84, and SYTOX Orange resulted in the shortest Tt, and SYTO-81 had the widest range of working concentrations. The optimized protocol detected 10 genome copies of Mycobacterium tuberculosis in less than 10 min, 10 copies of Giardia intestinalis in ~20 min, and 10 copies of Staphylococcus aureus or Salmonella enterica in less than 15 min. Results demonstrate that reaction efficiency depends on both dye type and concentration and the selected polymerase. The optimized protocol was evaluated in the Gene-Z™ device, a hand-held battery operated platform characterized via simple and low cost optics, and a multiple assay microfluidic chip with micron volume reaction wells. Compared to the more conventional intercalating dye (SYBR Green), reliable amplification was only observed in the Gene-Z™ when using higher concentrations of SYTO-81. PMID:26554941

  18. Real-time quantitative fluorescence imaging using a single snapshot optical properties technique for neurosurgical guidance

    NASA Astrophysics Data System (ADS)

    Valdes, Pablo A.; Angelo, Joseph; Gioux, Sylvain

    2015-03-01

    Fluorescence imaging has shown promise as an adjunct to improve the extent of resection in neurosurgery and oncologic surgery. Nevertheless, current fluorescence imaging techniques do not account for the heterogeneous attenuation effects of tissue optical properties. In this work, we present a novel imaging system that performs real time quantitative fluorescence imaging using Single Snapshot Optical Properties (SSOP) imaging. We developed the technique and performed initial phantom studies to validate the quantitative capabilities of the system for intraoperative feasibility. Overall, this work introduces a novel real-time quantitative fluorescence imaging method capable of being used intraoperatively for neurosurgical guidance.

  19. Real-time precision concentration measurement for flowing liquid solutions

    NASA Astrophysics Data System (ADS)

    Krishna, V.; Fan, C. H.; Longtin, J. P.

    2000-10-01

    The precise, real-time measurement of liquid concentration is important in fundamental research, chemical analysis, mixing processes, and manufacturing, e.g., in the food and semiconductor industries. This work presents a laser-based, noninvasive technique to measure concentration changes of flowing liquids in real time. The essential components in the system include a 5 mW laser diode coupled to a single-mode optical fiber, a triangular optical cell, and a high-resolution beam position sensor. The instrument provides a large range of concentration measurement, typically 0%-100% for binary liquid mixtures, while providing a resolution on the order of 0.05% concentration or better. The experimental configuration is small, reliable, and inexpensive. Results are presented for NaCl and MgCl2 aqueous solutions with concentrations ranging from 0% to 25%, with very good agreement found between measured and true concentrations.

  20. Real-time water and wastewater quality monitoring using LED-based fluorescence spectroscopy

    NASA Astrophysics Data System (ADS)

    Bridgeman, John; Zakharova, Yulia

    2016-04-01

    In recent years there have been a number of attempts to design and introduce into water management tools that are capable of measuring organic and microbial matter in real time and in situ. This is important, as the delivery of safe water to customers, and the discharge of good quality effluent to rivers are primary concerns to water undertakers. A novel, LED-based portable fluorimeter 'Duo Fluor' has been designed and constructed at the University of Birmingham to monitor the quality of (waste)water continuously and in real time, and its performance has been assessed in a range of environments. To be of use across a range of environments, special attention must be paid to two crucially important characteristics of such instruments, i.e. their sensitivity and robustness. Thus, the objectives of this study were: 1. To compare the performance (in terms of their sensitivity and robustness) of the Duo Fluor and two other commercial fluorescence devices in laboratory conditions. 2. To assess the performance of the Duo Fluor in situ, in real time at a 450,000PE WwTW. Initially, the impact of quinine sulphate (QS), a highly fluorescent alkaloid with high quantum fluorescence yield, on peak T fluorescence in environmental waters was examined for the Duo Fluor and two commercially available, chamber-based fluorimeters, (F1) and (F2). The instruments' responses to three scenarios were assessed: 1. Deionised water (DW) spiked with QS (from 0.05 to 0.4 mg/L); 2. Environmental water (pond water, PW) spiked with QS (from 0.05 to 0.4 mg/L); 3. Different water samples from various environmental source. The results show that the facility to amend gain settings and the suitable choice of gain are crucial to obtaining reliable data on both peaks T and C in a wide range of water types. The Duo Fluor offers both of these advantages whilst commercially available instruments currently do not. The Duo Fluor was subsequently fixed at the final effluent (FE) discharge point of a WwTW and FE

  1. Real-Time Dynamics Monitoring System with Synchronized Phasor Measurements

    Energy Science and Technology Software Center (ESTSC)

    2005-01-01

    The Real-Time Dynamics Monitoring System is designed to monitor the dynamics within the power grid and assess the system behavior during normal and disturbance conditions. The RTDMS application was built on the Grid-3P technology platform and takes real-time information collected by Synchronized Phasor Measurement Units (PMU5) or other collection devices and transmitted to a central Phasor Data Concentrator (PDC) for monitoring grid dynamics. The data is sampled 30 times per second and is time-synchronized. Thismore » data is processed to create graphical and geographical displays to provide visualization for frequency/frequency response, voltage magnitudes and angles, voltage angle differences across critical paths as well as real and reactive power-flows on a sub-second and second basis. Software allows for monitoring, tracking, historical data archiving and electric system troubleshooting for reliability management.« less

  2. Real-time fluorescence lifetime actuation for cell sorting using a CMOS SPAD silicon photomultiplier.

    PubMed

    Rocca, Francescopaolo Mattioli Della; Nedbal, Jakub; Tyndall, David; Krstajić, Nikola; Li, David Day-Uei; Ameer-Beg, Simon M; Henderson, Robert K

    2016-02-15

    Time-correlated single photon counting (TCSPC) is a fundamental fluorescence lifetime measurement technique offering high signal to noise ratio (SNR). However, its requirement for complex software algorithms for histogram processing restricts throughput in flow cytometers and prevents on-the-fly sorting of cells. We present a single-point digital silicon photomultiplier (SiPM) detector accomplishing real-time fluorescence lifetime-activated actuation targeting cell sorting applications in flow cytometry. The sensor also achieves burst-integrated fluorescence lifetime (BIFL) detection by TCSPC. The SiPM is a single-chip complementary metal-oxide-semiconductor (CMOS) sensor employing a 32×32 single-photon avalanche diode (SPAD) array and eight pairs of time-interleaved time to digital converters (TI-TDCs) with a 50 ps minimum timing resolution. The sensor's pile-up resistant embedded center of mass method (CMM) processor accomplishes low-latency measurement and thresholding of fluorescence lifetime. A digital control signal is generated with a 16.6 μs latency for cell sorter actuation allowing a maximum cell throughput of 60,000 cells per second and an error rate of 0.6%. PMID:26872160

  3. Real time monitoring of superoxide dynamics in vivo through fluorescent proteins using a sensitive fiber probe

    NASA Astrophysics Data System (ADS)

    Chang, Yu-Chung; Ken, Chuian-Fu; Hsu, Che-Wei; Liu, Ya-Ging

    2014-03-01

    Superoxide anion is the primary oxygen free radical generated in mitochondria that causes intracellular oxidative stress. The lack of a method to directly monitor superoxide concentration in vivo in real time has severely hindered our understanding on its pathophysiology. We made transgenic zebrafish to specifically express fluorescent proteins, which are recently developed as reversible superoxide-specific indicators, in the liver. A fiber-optic fluorescent probe was used to noninvasively monitor superoxide generation in the liver in real time. The fish were placed in microfluidic channels for manipulation and reagents administration. Several superoxide-inducing and scavenging reagents were administrated onto the fish to investigate their effects on superoxide anion balancing. The biochemical dynamics of superoxide due to the application reagents were revealed in the transient behaviors of fluorescence time courses. With the ability to monitor superoxide dynamics in vivo in real time, this method can be used as an in vivo pharmaceutical screening platform.

  4. Continuous real-time measurement of aqueous cyanide

    DOEpatents

    Rosentreter, Jeffrey J.; Gering, Kevin L.

    2007-03-06

    This invention provides a method and system capable of the continuous, real-time measurement of low concentrations of aqueous free cyanide (CN) using an on-line, flow through system. The system is based on the selective reactivity of cyanide anions and the characteristically nonreactive nature of metallic gold films, wherein this selective reactivity is exploited as an indirect measurement for aqueous cyanide. In the present invention the dissolution of gold, due to the solubilization reaction with the analyte cyanide anion, is monitored using a piezoelectric microbalance contained within a flow cell.

  5. Nondestructive and Real-time Measurement of Moisture in Plant

    NASA Astrophysics Data System (ADS)

    Ogawa, Yuichi; Kawase, Kodo; Mizuno, Maya; Yamashita, Masatsugu; Otani, Chiko

    We constructed a THz transillumination system for water content monitoring, and we succeeded in measuring the moisture level in plants. Our measurement system uses a widely tunable coherent THz parametric oscillator source. As target we chose for this experiment a leaf of Japanese basil. The time variation of the water content in the leaf was monitored in two situations: a leaf freshly cut which is left to dry out, and the leaf of a water stressed plant. We found by real-time measurements that the water content of a cut leaf does not decrease uniformly in time. Also, the response to water stress is delayed by about 5-10 minutes. Furthermore, we demonstrated a moisture measurement using a transillumination THz imaging system. As target we chose for this experiment a leaf of Hedera helix held between two thin plastic sheets. The change of the moisture distribution is clearly visible. These results show that the method described here can be applied to nondestructive and real-time monitoring of water content in plants.

  6. TRANSIENT, REAL-TIME, PARTICULATE EMISSION MEASUREMENTS IN DIESEL ENGINES

    SciTech Connect

    Gupta, S; Shih, J; Hillman, G; sekar, R; Graze, R; Shimpi, S; Martin, W; Pier, D

    2003-08-24

    This paper reports our efforts to develop an instrument, TG-1, to measure particulate emissions from diesel engines in real-time. TG-1 while based on laser-induced incandescence allows measurements at 10 Hz on typical engine exhausts. Using such an instrument, measurements were performed in the exhaust of a 1.7L Mercedes Benz engine coupled to a low inertia dynamometer. Comparative measurements performed under engine steady state conditions showed the instrument to agree within {+-}12% of measurements performed with an SMPS. Moreover, the instrument had far better time response and time resolution than a TEOM{reg_sign} 1105. Also, TG-1 appears to surpass the shortcomings of the TEOM instrument, i.e., of yielding negative values under certain engine conditions and, being sensitive to external vibration.

  7. Real-Time performance measurements of EPICS IOCcore.

    SciTech Connect

    Xu, S.; Kraimer, M. R.; Accelerator Systems Division

    2005-01-01

    As the Experimental Physics and Industrial Control System (EPICS) is used in an increasing number of accelerator control systems, EPICS IOCcore is ported to a wider variety of OS platforms and thus the performance of EPICS IOCcore on different hardware and software platforms becomes more important. This paper provides real-time performance measurements of EPICS IOCcore on a VME hardware platform and on three different OS platforms: vxWorks, RTEMS, and Linux. EPICS Input/Output Controller core (IOCcore) software has been ported to several different operating systems (OSs) and many hardware platforms. This paper compares the EPICS IOCcore runtime performance on one hardware platform (MVME2100 PowerPC) and three popular Operating Systems: vxWorks, RTEMS, and Linux. For Linux the following versions were tested: Linux 2.4.2 hard hat 2.0, standard Linux 2.4.30, and Linux 2.6.13. For Linux 2.6.13, the kernel was built both preemptive and non-preemptive. Three real-time parameters are measured: interrupt, context switch, and total response latency. On Linux, more detailed interrupt latencies are measured: interrupt top half to bottom half, and interrupt bottom half to user space interrupt service routine. To implement the tests, several software components were developed. In order to port to other operating systems or hardware platforms only, one component has to be implemented.

  8. Real-Time Coil Position Monitoring System for Biomagnetic Measurements

    NASA Astrophysics Data System (ADS)

    Oyama, Daisuke; Adachi, Yoshiaki; Higuchi, Masanori; Kawai, Jun; Kobayashi, Koichiro; Uehara, Gen

    In this paper, we propose a new method for monitoring the position of marker coils. The marker coil is used for indicating spatial relationship between subject's body and magnetic sensor arrays in biomagnetic measurements, such as magnetoencephalography (MEG) and magnetocardiography (MCG). We developed a real-time marker coil position monitoring system combined with a conventional MEG system. In order to achieve simultaneous measurement of MEG signals and marker signals, we separated their frequency bands. The frequency bands of flux-locked loop (FLL) circuits were separated into three parts by three integrators; low-band, mid-band, and high-band. The second and third bands were assigned for MEG signals and marker signals, respectively. This method can avoid the crosstalk of the marker signals to MEG signals. Marker signals were generated from five marker coils driven by five independent sinusoidal current generators. These signals were continuously measured by the high-band of FLL, and then the coils were localized by FFT processing and solving inverse problem. We succeeded in displaying the localized coil position on a PC monitor once per second in real-time.

  9. Real-time label-free quantitative fluorescence microscopy-based detection of ATP using a tunable fluorescent nano-aptasensor platform

    NASA Astrophysics Data System (ADS)

    Shrivastava, Sajal; Sohn, Il-Yung; Son, Young-Min; Lee, Won-Il; Lee, Nae-Eung

    2015-11-01

    Although real-time label-free fluorescent aptasensors based on nanomaterials are increasingly recognized as a useful strategy for the detection of target biomolecules with high fidelity, the lack of an imaging-based quantitative measurement platform limits their implementation with biological samples. Here we introduce an ensemble strategy for a real-time label-free fluorescent graphene (Gr) aptasensor platform. This platform employs aptamer length-dependent tunability, thus enabling the reagentless quantitative detection of biomolecules through computational processing coupled with real-time fluorescence imaging data. We demonstrate that this strategy effectively delivers dose-dependent quantitative readouts of adenosine triphosphate (ATP) concentration on chemical vapor deposited (CVD) Gr and reduced graphene oxide (rGO) surfaces, thereby providing cytotoxicity assessment. Compared with conventional fluorescence spectrometry methods, our highly efficient, universally applicable, and rational approach will facilitate broader implementation of imaging-based biosensing platforms for the quantitative evaluation of a range of target molecules.Although real-time label-free fluorescent aptasensors based on nanomaterials are increasingly recognized as a useful strategy for the detection of target biomolecules with high fidelity, the lack of an imaging-based quantitative measurement platform limits their implementation with biological samples. Here we introduce an ensemble strategy for a real-time label-free fluorescent graphene (Gr) aptasensor platform. This platform employs aptamer length-dependent tunability, thus enabling the reagentless quantitative detection of biomolecules through computational processing coupled with real-time fluorescence imaging data. We demonstrate that this strategy effectively delivers dose-dependent quantitative readouts of adenosine triphosphate (ATP) concentration on chemical vapor deposited (CVD) Gr and reduced graphene oxide (r

  10. Real-time background suppression during frequency domain lifetime measurements.

    PubMed

    Herman, Petr; Maliwal, Badri P; Lakowicz, Joseph R; Maliwal, Baldri P

    2002-10-01

    We describe real time background suppression of autofluorescence from biological samples during frequency domain or phase modulation measurements of intensity decays. For these measurements the samples were excited with a train of light pulses with widths below 1 ps. The detector was gated off for a short time period of 10 to 40 ns during and shortly after the excitation pulse. The reference signal needed for the frequency domain measurement was provided by a long-lifetime reference fluorophore which continues to emit following the off-gating pulse. Both the sample and the reference were measured under identical optical and electronic conditions avoiding the need for correction of the photomultiplier tube signal for the gating sequence. We demonstrate frequency domain background suppression using a mixture of short- and long-lifetime probes and for a long-lifetime probe in human plasma with significant autofluorescence. PMID:12381357

  11. Real time monitoring of urban surface water quality using a submersible, tryptophan-like fluorescence sensor

    NASA Astrophysics Data System (ADS)

    Khamis, Kieran; Bradley, Chris; Hannah, David; Stevens, Rob

    2014-05-01

    Due to the recent development of field-deployable optical sensor technology, continuous quantification and characterization of surface water dissolved organic matter (DOM) is possible now. Tryptophan-like (T1) fluorescence has the potential to be a particularly useful indicator of human influence on water quality as T1 peaks are associated with the input of labial organic carbon (e.g. sewage or farm waste) and its microbial breakdown. Hence, real-time recording of T1 fluorescence could be particular useful for monitoring waste water infrastructure, treatment efficiency and the identification of contamination events at higher temporal resolution than available hitherto. However, an understanding of sensor measurement repeatability/transferability and interaction with environmental parameters (e.g. turbidity) is required. Here, to address this practical knowledge gap, we present results from a rigorous test of a commercially available submersible tryptophan fluorometer (λex 285, λem 350). Sensor performance was first examined in the laboratory by incrementally increasing turbidity under controlled conditions. Further to this the sensor was integrated into a multi-parameter sonde and field tests were undertaken involving: (i) a spatial sampling campaign across a range of surface water sites in the West Midlands, UK; and (ii) collection of high resolution (sub-hourly) samples from an urban stream (Bournbrook, Birmingham, U.K). To determine the ability of the sensor to capture spatiotemporal dynamics of urban waters DOM was characterized for each site or discrete time step using Excitation Emission Matrix spectroscopy and PARAFAC. In both field and laboratory settings fluorescence intensity was attenuated at high turbidity due to suspended particles increasing absorption and light scattering. For the spatial survey, instrument readings were compared to those obtained by a laboratory grade fluorometer (Varian Cary Eclipse) and a strong, linear relationship was apparent

  12. DEVELOPMENT OF A REAL-TIME FLUORESCENCE RESONANCE ENERGY TRANSFER (FRET) PCR TO DETECT ARCOBACTER SPECIES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A real-time PCR targeting the gyrase A subunit gene outside the quinolone resistance-determining region has been developed to detect Arcobacter species. The species identification was made by probe hybridization and melting curve analysis, using the Fluorescence Resonance Energy Transfer technology...

  13. DEVELOPMENT OF A REAL-TIME FLUORESCENCE RESONANCE ENERGY TRANSFER PCR TO DETECT ARCOBACTER SPECIES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A real-time PCR targeting the gyrase A subunit gene outside the quinolone resistance-determining region has been developed to detect Arcobacter species. The species identification was made by probe hybridization and melting curve analysis, using Fluorescence Resonance Energy Transfer technology. D...

  14. Real-time control of sewer systems using turbidity measurements.

    PubMed

    Lacour, C; Schütze, M

    2011-01-01

    Real-time control (RTC) of urban drainage systems has been proven useful as a means to reduce pollution by combined sewer overflow discharges. So far, RTC has been investigated mainly with a sole focus on water quantity aspects. However, as measurement techniques for pollution of wastewater are advancing, pollution-based RTC might be of increasing interest. For example, turbidity data sets from an extensive measurement programme in two Paris catchments allow a detailed investigation of the benefits of using pollution-based data for RTC. This paper exemplifies this, comparing pollution-based RTC with flow-based RTC. Results suggest that pollution-based RTC indeed has some potential, particularly when measurements of water-quality characteristics are readily available. PMID:22049758

  15. Improved process control through real-time measurement of mineral content

    SciTech Connect

    Turler, Daniel; Karaca, Murat; Davis, William B.; Giauque, Robert D.; Hopkins, Deborah

    2001-11-02

    In a highly collaborative research and development project with mining and university partners, sensors and data-analysis tools are being developed for rock-mass characterization and real-time measurement of mineral content. Determining mineralogy prior to mucking in an open-pit mine is important for routing the material to the appropriate processing stream. A possible alternative to lab assay of dust and cuttings obtained from drill holes is continuous on-line sampling and real-time x-ray fluorescence (XRF) spectroscopy. Results presented demonstrate that statistical analyses combined with XRF data can be employed to identify minerals and, possibly, different rock types. The objective is to create a detailed three-dimensional mineralogical map in real time that would improve downstream process efficiency.

  16. Fluorescence Correlation Spectroscopy to Monitor Kai Protein-based Circadian Oscillations in Real Time*

    PubMed Central

    Goda, Kazuhito; Ito, Hiroshi; Kondo, Takao; Oyama, Tokitaka

    2012-01-01

    Dynamic protein-protein interactions play an essential role in cellular regulatory systems. The cyanobacterial circadian clock is an oscillatory system that can be reconstituted in vitro by mixing ATP and three clock proteins: KaiA, KaiB, and KaiC. Association and dissociation of KaiB from KaiC-containing complexes are critical to circadian phosphorylation and dephosphorylation of KaiC. We developed an automated and noninvasive method to monitor dynamic complex formation in real time using confocal fluorescence correlation spectroscopy (FCS) and uniformly labeled KaiB as a probe. A nanomolar concentration of the labeled KaiB for FCS measurement did not interfere with the oscillatory system but behaved similarly to the wild-type one during the measurement period (>5 days). The fluorescent probe was stable against repeated laser exposure. As an application, we show that this detection system allowed analysis of the dynamics of both long term circadian oscillations and short term responses to temperature changes (∼10 min) in the same sample. This suggested that a phase shift of the clock with a high temperature pulse occurred just after the stimulus through dissociation of KaiB from the KaiC complex. This monitoring method should improve our understanding of the mechanisms underlying this cellular circadian oscillator and provide a means to assess dynamic protein interactions in biological systems characterized by rates similar to those observed with the Kai proteins. PMID:22157012

  17. Detection of shrimp-derived components in food by real-time fluorescent PCR.

    PubMed

    Cao, Jijuan; Yu, Bing; Ma, Lidan; Zheng, Qiuyue; Zhao, Xin; Xu, Junyi

    2011-10-01

    Crustaceans such as shrimp and crabs and their products are important allergens in food, and allergic reactions due to the consumption of shrimp and crabs are frequently reported. However, the chemical properties of shrimp-derived allergens, except for Pen a I, are still unclear. Therefore, it is important to establish a more sensitive and specific method for detecting the composition of foods containing shrimp. In the present study, we developed a real-time fluorescent PCR to identify the specific shrimp-derived components in food. The primers and TaqMan probes for real-time fluorescent PCR were designed based on 16S rRNA genes through comparing a large number of nucleic acid sequences from different species of shrimp that have been published by the National Center for Biotechnology Information. In total, 56 kinds of samples, including different kinds of shrimp, crab, fish, shellfish, and octopus, were subjected to detection by real-time PCR. The results indicated that real-time fluorescent PCR could successfully identify the shrimp-derived components. In order to explore the effect of food processing on detection sensitivity, fish powder containing shrimp powder was treated by heating at 133°C for 30 min. The limit of detection of shrimp-derived components in fish powder was 0.05% (wt/wt). PMID:22004830

  18. Real time bunch length measurements in the SLC linac

    SciTech Connect

    Sheppard, J.C.; Clendenin, J.E.; James, M.B.; Miller, R.H.; Ross, M.C.

    1985-02-01

    The longitudinal charge distribution of bunches accelerated in the Stanford Linear Collider (SLC) linac will strongly affect the performance of the Collider. Bunch lengths are chosen in a balance between the deleterious effects of longitudinal and transverse wakefields. The former impacts on the beam energy spread whereas the latter is important to the transverse emittance. Two bunch length measurement ports have been installed in the SLC linac: one in the injector region and one after the emittance damping ring to linac reinjection point. These ports utilize a fused quartz Cerenkov radiator in conjunction with an electrooptic streak camera to permit real time monitoring of single s-band buckets with a resolution of several picoseconds. The design of the radiators and light collection optics is discussed with an emphasis on those issues important to high resolution. Experimental results are presented. 7 refs., 4 figs.

  19. Real-time diamagnetic flux measurements on ASDEX Upgrade.

    PubMed

    Giannone, L; Geiger, B; Bilato, R; Maraschek, M; Odstrčil, T; Fischer, R; Fuchs, J C; McCarthy, P J; Mertens, V; Schuhbeck, K H

    2016-05-01

    Real-time diamagnetic flux measurements are now available on ASDEX Upgrade. In contrast to the majority of diamagnetic flux measurements on other tokamaks, no analog summation of signals is necessary for measuring the change in toroidal flux or for removing contributions arising from unwanted coupling to the plasma and poloidal field coil currents. To achieve the highest possible sensitivity, the diamagnetic measurement and compensation coil integrators are triggered shortly before plasma initiation when the toroidal field coil current is close to its maximum. In this way, the integration time can be chosen to measure only the small changes in flux due to the presence of plasma. Two identical plasma discharges with positive and negative magnetic field have shown that the alignment error with respect to the plasma current is negligible. The measured diamagnetic flux is compared to that predicted by TRANSP simulations. The poloidal beta inferred from the diamagnetic flux measurement is compared to the values calculated from magnetic equilibrium reconstruction codes. The diamagnetic flux measurement and TRANSP simulation can be used together to estimate the coupled power in discharges with dominant ion cyclotron resonance heating. PMID:27250425

  20. Designing Information Measures for Real-time Lightcurve Classification

    NASA Astrophysics Data System (ADS)

    Jones, David Edward; Chen, Yang; Meng, Xiao-Li; Siemiginowska, Aneta; Kashyap, Vinay

    2016-01-01

    Since telescope time is limited, real-time lightcurve classification involves carefully selecting future time points at which sources must be observed in order to maximize the information that will be gained for classification. We propose a framework for constructing measures of information for testing/classification/model-selection and demonstrate their use in experimental design. Degroot (1962) developed a general framework for constructing Bayesian measures of the expected information that an experiment will provide for estimation, and our framework analogously constructs measures of information for hypothesis testing. Such test information measures are most useful for model selection and classification problems. Indeed, our framework suggests a probability based measure of test information, which in decision problems has more appealing properties than variance based measures. In the case of lightcurve classification, we adapt our designs to penalize long waits until the next observation time. Lastly, we consider ways to address other aspects of the problem, such as uncertainty estimation arising due to contamination from nearby contaminating sources or background diffuse emission. We acknowledge support from Smithsonian Competitive Grants Fund 40488100HH0043 and NSF grant DMS 1208791.

  1. Real-time maximum a-posteriori image reconstruction for fluorescence microscopy

    NASA Astrophysics Data System (ADS)

    Jabbar, Anwar A.; Dilipkumar, Shilpa; C K, Rasmi; Rajan, K.; Mondal, Partha P.

    2015-08-01

    Rapid reconstruction of multidimensional image is crucial for enabling real-time 3D fluorescence imaging. This becomes a key factor for imaging rapidly occurring events in the cellular environment. To facilitate real-time imaging, we have developed a graphics processing unit (GPU) based real-time maximum a-posteriori (MAP) image reconstruction system. The parallel processing capability of GPU device that consists of a large number of tiny processing cores and the adaptability of image reconstruction algorithm to parallel processing (that employ multiple independent computing modules called threads) results in high temporal resolution. Moreover, the proposed quadratic potential based MAP algorithm effectively deconvolves the images as well as suppresses the noise. The multi-node multi-threaded GPU and the Compute Unified Device Architecture (CUDA) efficiently execute the iterative image reconstruction algorithm that is ≈200-fold faster (for large dataset) when compared to existing CPU based systems.

  2. Real-Time Measurement of Vehicle Exhaust Gas Flow

    SciTech Connect

    Hardy, J.E.; Hylton, J.O.; Joy, R.D.; McKnight, T.E.

    1999-06-28

    A flow measurement system was developed to measure, in real-time, the exhaust gas flow from vehicies. This new system was based on the vortex shedding principle using ultrasonic detectors for sensing the shed vortices. The flow meter was designed to measure flow over a range of 1 to 366 Ips with an inaccuracy of ~1o/0 of reading. Additionally, the meter was engineered to cause minimal pressure drop (less than 125mm of water), to function in a high temperature environment (up to 650oC) with thermal transients of 15 oC/s, and to have a response time of 0.1 seconds for a 10% to 90!40 step change. The flow meter was also configured to measure hi-directional flow. Several flow meter prototypes were fabricated, tested, and calibrated in air, simulated exhaust gas, and actual exhaust gas. Testing included gas temperatures to 600oC, step response experiments, and flow rates from O to 360 lps in air and exhaust gas. Two prototypes have been tested extensively at NIST and two additional meters have been installed in exhaust gas flow lines for over one year. This new flow meter design has shown to be accurate, durabIe, fast responding, and to have a wide rangeabi~ity.

  3. Quantify single nucleotide polymorphism (SNP) ratio in pooled DNA based on normalized fluorescence real-time PCR

    PubMed Central

    Yu, Airong; Geng, Haifeng; Zhou, Xuerui

    2006-01-01

    Background Conventional real-time PCR to quantify the allele ratio in pooled DNA mainly depends on PCR amplification efficiency determination and Ct value, which is defined as the PCR cycle number at which the fluorescence emission exceeds the fixed threshold. Because of the nature of exponential calculation, slight errors are multiplied and the variations of the results seem too large. We have developed a new PCR data point analysis strategy for allele ratio quantification based on normalized fluorescence ratio. Results In our method, initial reaction background fluorescence was determined based upon fitting of raw fluorescence data to four-parametric sigmoid function. After that, each fluorescence data point was first subtracted by respective background fluorescence and then each subtracted fluorescence data point was divided by the specific background fluorescence to get normalized fluorescence. By relating the normalized fluorescence ratio to the premixed known allele ratio of two alleles in standard samples, standard linear regression equation was generated, from which unknown specimens allele ratios were extrapolated using the measured normalized fluorescence ratio. In this article, we have compared the results of the proposed method with those of baseline subtracted fluorescence ratio method and conventional Ct method. Conclusion Results demonstrated that the proposed method could improve the reliability, precision, and repeatability for quantifying allele ratios. At the same time, it has the potential of fully automatic allelic ratio quantification. PMID:16764712

  4. An accurate assay for HCV based on real-time fluorescence detection of isothermal RNA amplification.

    PubMed

    Wu, Xuping; Wang, Jianfang; Song, Jinyun; Li, Jiayan; Yang, Yongfeng

    2016-09-01

    Hepatitis C virus (HCV) is one of the common reasons of liver fibrosis and hepatocellular carcinoma (HCC). Early, rapid and accurate HCV RNA detection is important to prevent and control liver disease. A simultaneous amplification and testing (SAT) assay, which is based on isothermal amplification of RNA and real-time fluorescence detection, was designed to optimize routine HCV RNA detection. In this study, HCV RNA and an internal control (IC) were amplified and analyzed simultaneously by SAT assay and detection of fluorescence using routine real-time PCR equipment. The assay detected as few as 10 copies of HCV RNA transcripts. We tested 705 serum samples with SAT, among which 96.4% (680/705) showed consistent results compared with routine real-time PCR. About 92% (23/25) discordant samples were confirmed to be same results as SAT-HCV by using a second real-time PCR. The sensitivity and specificity of SAT-HCV assay were 99.6% (461/463) and 100% (242/242), respectively. In conclusion, the SAT assay is an accurate test with a high specificity and sensitivity which may increase the detection rate of HCV. It is therefore a promising tool to diagnose HCV infection. PMID:27283884

  5. Accuracy of real time radiography burning rate measurement

    NASA Astrophysics Data System (ADS)

    Olaniyi, Bisola

    The design of a solid propellant rocket motor requires the determination of a propellant's burning-rate and its dependency upon environmental parameters. The requirement that the burning-rate be physically measured, establishes the need for methods and equipment to obtain such data. A literature review reveals that no measurement has provided the desired burning rate accuracy. In the current study, flash x-ray modeling and digitized film-density data were employed to predict motor-port area to length ratio. The pre-fired port-areas and base burning rate were within 2.5% and 1.2% of their known values, respectively. To verify the accuracy of the method, a continuous x-ray and a solid propellant rocket motor model (Plexiglas cylinder) were used. The solid propellant motor model was translated laterally through a real-time radiography system at different speeds simulating different burning rates. X-ray images were captured and the burning-rate was then determined. The measured burning rate was within 1.65% of the known values.

  6. A model system using confocal fluorescence microscopy for examining real-time intracellular sodium ion regulation.

    PubMed

    Lee, Jacqueline A; Collings, David A; Glover, Chris N

    2016-08-15

    The gills of euryhaline fish are the ultimate ionoregulatory tissue, achieving ion homeostasis despite rapid and significant changes in external salinity. Cellular handling of sodium is not only critical for salt and water balance but is also directly linked to other essential functions such as acid-base homeostasis and nitrogen excretion. However, although measurement of intracellular sodium ([Na(+)]i) is important for an understanding of gill transport function, it is challenging and subject to methodological artifacts. Using gill filaments from a model euryhaline fish, inanga (Galaxias maculatus), the suitability of the fluorescent dye CoroNa Green as a probe for measuring [Na(+)]i in intact ionocytes was confirmed via confocal microscopy. Cell viability was verified, optimal dye loading parameters were determined, and the dye-ion dissociation constant was measured. Application of the technique to freshwater- and 100% seawater-acclimated inanga showed salinity-dependent changes in branchial [Na(+)]i, whereas no significant differences in branchial [Na(+)]i were determined in 50% seawater-acclimated fish. This technique facilitates the examination of real-time changes in gill [Na(+)]i in response to environmental factors and may offer significant insight into key homeostatic functions associated with the fish gill and the principles of sodium ion transport in other tissues and organisms. PMID:27235170

  7. Compact wearable dual-mode imaging system for real-time fluorescence image-guided surgery

    NASA Astrophysics Data System (ADS)

    Zhu, Nan; Huang, Chih-Yu; Mondal, Suman; Gao, Shengkui; Huang, Chongyuan; Gruev, Viktor; Achilefu, Samuel; Liang, Rongguang

    2015-09-01

    A wearable all-plastic imaging system for real-time fluorescence image-guided surgery is presented. The compact size of the system is especially suitable for applications in the operating room. The system consists of a dual-mode imaging system, see-through goggle, autofocusing, and auto-contrast tuning modules. The paper will discuss the system design and demonstrate the system performance.

  8. Compact wearable dual-mode imaging system for real-time fluorescence image-guided surgery.

    PubMed

    Zhu, Nan; Huang, Chih-Yu; Mondal, Suman; Gao, Shengkui; Huang, Chongyuan; Gruev, Viktor; Achilefu, Samuel; Liang, Rongguang

    2015-09-01

    A wearable all-plastic imaging system for real-time fluorescence image-guided surgery is presented. The compact size of the system is especially suitable for applications in the operating room. The system consists of a dual-mode imaging system, see-through goggle, autofocusing, and auto-contrast tuning modules. The paper will discuss the system design and demonstrate the system performance. PMID:26358823

  9. Real-Time Dopamine Measurement in Awake Monkeys

    PubMed Central

    Schluter, Erik W.; Mitz, Andrew R.; Cheer, Joseph F.; Averbeck, Bruno B.

    2014-01-01

    Fast-scan cyclic voltammetry (FSCV) is often used to measure real-time dopamine (DA) concentrations in awake, behaving rodents. Extending this technique to work in monkeys would provide a platform for advanced behavioral studies and a primate model for preclinical research. The present study demonstrates the feasibility of DA recordings in two awake monkeys (Macaca mulatta) using a mixture of techniques adapted from rodent, primate and brain slice work. We developed a long carbon fiber electrode to operate in the larger primate brain. This electrode was lowered into the striatum each day using a recording chamber and a detachable micromanipulator system. A manipulator also moved one or more tungsten stimulating electrodes into either the nearby striatum or the ventral tegmental area/substantia nigra pars compacta (VTA/SNc). We developed an electrical stimulation controller to reduce artifacts during electrical stimulation. We also introduce a stimulation-based methodology for estimating distances between electrodes in the brain. Dopamine responses within the striatum were evoked by either stimulation of the striatum near the FSCV electrode, or stimulation within the VTA/SNc. Unexpected juice rewards also evoked dopamine responses in the ventral striatum. Thus, we demonstrate that robust dopamine responses can be recorded from awake, behaving primates with FSCV. In addition, we describe how a stimulation technique borrowed from the neuroprosthetics field can activate the distributed monkey midbrain dopamine system in a way that mimics rodent VTA stimulation. PMID:24921937

  10. Real-time dopamine measurement in awake monkeys.

    PubMed

    Schluter, Erik W; Mitz, Andrew R; Cheer, Joseph F; Averbeck, Bruno B

    2014-01-01

    Fast-scan cyclic voltammetry (FSCV) is often used to measure real-time dopamine (DA) concentrations in awake, behaving rodents. Extending this technique to work in monkeys would provide a platform for advanced behavioral studies and a primate model for preclinical research. The present study demonstrates the feasibility of DA recordings in two awake monkeys (Macaca mulatta) using a mixture of techniques adapted from rodent, primate and brain slice work. We developed a long carbon fiber electrode to operate in the larger primate brain. This electrode was lowered into the striatum each day using a recording chamber and a detachable micromanipulator system. A manipulator also moved one or more tungsten stimulating electrodes into either the nearby striatum or the ventral tegmental area/substantia nigra pars compacta (VTA/SNc). We developed an electrical stimulation controller to reduce artifacts during electrical stimulation. We also introduce a stimulation-based methodology for estimating distances between electrodes in the brain. Dopamine responses within the striatum were evoked by either stimulation of the striatum near the FSCV electrode, or stimulation within the VTA/SNc. Unexpected juice rewards also evoked dopamine responses in the ventral striatum. Thus, we demonstrate that robust dopamine responses can be recorded from awake, behaving primates with FSCV. In addition, we describe how a stimulation technique borrowed from the neuroprosthetics field can activate the distributed monkey midbrain dopamine system in a way that mimics rodent VTA stimulation. PMID:24921937

  11. Real-time biological agent detection using particle size, shape, and fluorescence characterisation

    NASA Astrophysics Data System (ADS)

    Shelton, Matthew J.; Evans, Steve P.; Smith, Paul D.; Simpson, Innes A.; Kaye, Paul H.; Clark, James M.

    2004-12-01

    Developments in real time optical biological agent detection and sensing are presented which describe start of the art advances in the detection and warning of these pathogens. The following paper describes the basic operating principles of the current BIRAL ASAS (Aerosol Size and Shape) system which measures the optically determined particle properties, on a particle by particle basis, and uses the information to describe the size and shape characteristics of the aerosol. Furthermore, recent development of the existing technology to also encompass fluorescence detection is described, which significantly increases the detection ability of the ASAS aerosol suite. This operational improvement is a major advancement in the field of airborne biological agent detection and allows for near generic detection and warning. Applications of this device include all aspects of bio-aerosol monitoring, including the use as a biological agent detector and generic identifier, use as a general bio-agent monitor and also for use as a hazardous environment monitor. Such a device would be particularly useful in the fields of Armed Forces protection and National Defence either as a point detector or as a "plug and play" biosensor detector in a network.

  12. Real-time histology in liver disease using multiphoton microscopy with fluorescence lifetime imaging

    PubMed Central

    Wang, Haolu; Liang, Xiaowen; Mohammed, Yousuf H.; Thomas, James A.; Bridle, Kim R.; Thorling, Camilla A.; Grice, Jeffrey E.; Xu, Zhi Ping; Liu, Xin; Crawford, Darrell H. G.; Roberts, Michael S.

    2015-01-01

    Conventional histology with light microscopy is essential in the diagnosis of most liver diseases. Recently, a concept of real-time histology with optical biopsy has been advocated. In this study, live mice livers (normal, with fibrosis, steatosis, hepatocellular carcinoma and ischemia-reperfusion injury) were imaged by MPM-FLIM for stain-free real-time histology. The acquired MPM-FLIM images were compared with conventional histological images. MPM-FLIM imaged subsurface cellular and subcellular histopathological hallmarks of live liver in mice models at high resolution. Additional information such as distribution of stellate cell associated autofluorescence and fluorescence lifetime changes was also gathered by MPM-FLIM simultaneously, which cannot be obtained from conventional histology. MPM-FLIM could simultaneously image and quantify the cellular morphology and microenvironment of live livers without conventional biopsy or fluorescent dyes. We anticipate that in the near future MPM-FLIM will be evaluated from bench to bedside, leading to real-time histology and dynamic monitoring of human liver diseases. PMID:25798303

  13. Real-Time Near-Infrared Fluorescence-Guided Identification of the Ureters using Methylene Blue

    PubMed Central

    Matsui, Aya; Tanaka, Eiichi; Choi, Hak Soo; Kianzad, Vida; Gioux, Sylvain; Lomnes, Stephen J.; Frangioni, John V.

    2009-01-01

    Background The aim of this study was to determine whether the invisible near-infrared (NIR) fluorescence properties of methylene blue (MB), a dye already FDA-approved for other indications, could be exploited for real-time, intraoperative identification of the ureters. Methods The optical properties of MB were quantified in vitro. Open surgery and laparoscopic NIR fluorescence imaging systems were employed. Yorkshire pigs were injected intravenously with: 0.1 mg/kg MB (n = 8), 10 mg furosemide followed by 0.1 mg/kg MB (n = 6), or 0.5 mg/kg MB (n = 6). The contrast-to-background ratio (CBR) of the kidney and ureters, and MB concentration in urine, were quantified. Results Peak MB absorbance, emission, and intensity in urine occurred at 668 nm, 688 nm, and 20 μM, respectively. After intravenous injection, doses as low as 0.1 mg/kg MB provided prolonged imaging of the ureters, and a dose of 0.5 mg/kg provided statistically significant improvement of CBR. Pre-injection of furosemide increased urine volume but did not improve CBR. Laparoscopic identification of the ureter using MB NIR fluorescence was demonstrated. Conclusions Ureteral imaging using MB NIR fluorescence provides sensitive, real-time, intraoperative identification of the ureters during open and laparoscopic surgeries. PMID:20117811

  14. Real-time endoscopic guidance using near-infrared fluorescent light for thoracic surgery

    NASA Astrophysics Data System (ADS)

    Venugopal, Vivek; Stockdale, Alan; Neacsu, Florin; Kettenring, Frank; Frangioni, John V.; Gangadharan, Sidharta P.; Gioux, Sylvain

    2013-03-01

    Lung cancer is the leading cause of cancer death in the United States, accounting for 28% of all cancer deaths. Standard of care for potentially curable lung cancer involves preoperative radiographic or invasive staging, followed by surgical resection. With recent adjuvant chemotherapy and radiation studies showing a survival advantage in nodepositive patients, it is crucial to accurately stage these patients surgically in order to identify those who may benefit. However, lymphadenectomy in lung cancer is currently performed without guidance, mainly due to the lack of tools permitting real-time, intraoperative identification of lymph nodes. In this study we report the design and validation of a novel, clinically compatible near-infrared (NIR) fluorescence thoracoscope for real-time intraoperative guidance during lymphadenectomy. A novel, NIR-compatible, clinical rigid endoscope has been designed and fabricated, and coupled to a custom source and a dual channel camera to provide simultaneous color and NIR fluorescence information to the surgeon. The device has been successfully used in conjunction with a safe, FDA-approved fluorescent tracer to detect and resect mediastinal lymph nodes during thoracic surgery on Yorkshire pigs. Taken together, this study lays the foundation for the clinical translation of endoscopic NIR fluorescence intraoperative guidance and has the potential to profoundly impact the management of lung cancer patients.

  15. Real-time wavefront reconstruction from intensity measurements

    NASA Astrophysics Data System (ADS)

    Smith, Carlas; Marinica, Raluca; Verhaegen, Michel

    2013-12-01

    We propose an ecient approximation to the nonlinear phase diversity method for wavefront reconstruction method from intensity measurements in order to avoid the shortcomings of the nonlinear phase diversity method that prevent its real-time application, such as its computationally complex and the presence of local minima. The new method is called linear sequential phase diversity (LSPD). The method assumes that residual phase aberration is small and makes use of a rst order Taylor expansion of the point spread function (PSF). The Taylor expansion is performed in two dierent phase diversities, that can be arbitrary (large) pupil shapes in order to optimize the phase retrieval. For static aberrations LSPD makes use of two images that are collected at each iteration step of the algorithm. In each step the residual phase aberrations are estimated by solving a linear least squares problem, followed by the use of a deformable mirror to correct for the aberrations. The computational complexity of LSPD is O(m*m) - where m*m is the number of pixels. For the static case the convergence of the LSPD iterations have been studied and experimentally veried. In an extensive comparison the method is compared with the recently proposed method of [1]. This study demonstrates the improved performance both computationally and in accuracy with respect to existing competitors that also linearize the PSF. A further contribution of the paper is that we extend the static LSPD method to the case of dynamic wavefront reconstruction based on intensity measurements. Here the dynamics are assumed to be modelled standardly by a linear innovation model such that its spectrum e.g. approximates that given by Kolmogorov. The advantage of the application of the dynamic variant of the LSPD method is that in closed-loop the assumption that the residual phase aberration is small is justiable, since the goal of the controller is to reduce (minimize) the residual phase aberration. This unique contribution

  16. Real-time detection of DNA topological changes with a fluorescently labeled cruciform

    PubMed Central

    Jude, Kevin M.; Hartland, Abbey; Berger, James M.

    2013-01-01

    Topoisomerases are essential cellular enzymes that maintain the appropriate topological status of DNA and are the targets of several antibiotic and chemotherapeutic agents. High-throughput (HT) analysis is desirable to identify new topoisomerase inhibitors, but standard in vitro assays for DNA topology, such as gel electrophoresis, are time-consuming and are not amenable to HT analysis. We have exploited the observation that closed-circular DNA containing an inverted repeat can release the free energy stored in negatively supercoiled DNA by extruding the repeat as a cruciform. We inserted an inverted repeat containing a fluorophore-quencher pair into a plasmid to enable real-time monitoring of plasmid supercoiling by a bacterial topoisomerase, Escherichia coli gyrase. This substrate produces a fluorescent signal caused by the extrusion of the cruciform and separation of the labels as gyrase progressively underwinds the DNA. Subsequent relaxation by a eukaryotic topoisomerase, human topo IIα, causes reintegration of the cruciform and quenching of fluorescence. We used this approach to develop a HT screen for inhibitors of gyrase supercoiling. This work demonstrates that fluorescently labeled cruciforms are useful as general real-time indicators of changes in DNA topology that can be used to monitor the activity of DNA-dependent motor proteins. PMID:23680786

  17. Real-time observation of single-molecule fluorescence in microdroplet streams

    SciTech Connect

    Barnes, M.D.; Lermer, N.; Kung, C.; Whitten, W.B.; Ramsey, J.M.; Hill, S.C.

    1997-08-01

    We report real-time observation of fluorescence bursts from individual Rhodamine 6G molecules in streams of microdroplets (peak signal-to-noise ratios, {approx}30) whose trajectories are constrained with a linear electric quadrupole. This approach offers a reasonable dynamic range in droplet size (3{endash}12{minus}{mu}m diameter) with {lt}1{percent} shot-to-shot size fluctuations and sensitivity comparable with that of droplet levitation techniques with at least 10{sup 3} higher analysis rates. Applications to the study of single-molecule microcavity effects and stimulated emission are discussed.

  18. Real-time imaging of Mu opioid receptors by total internal reflection fluorescence microscopy

    PubMed Central

    Roman-Vendrell, Cristina; Yudowski, Guillermo Ariel

    2016-01-01

    Receptor trafficking and signaling are intimately linked, especially in the Mu opioid receptor (MOR) where ligand dependent endocytosis and recycling have been associated to opioid tolerance and dependence. Ligands of the Mu opioid receptor (MOR) can induce receptor endocytosis and recycling within minutes of exposure in heterologous systems and cultured neurons. Endocytosis removes desensitized receptors after their activation from the plasma membrane, while recycling promotes resensitization by delivering functional receptors to the cell surface. These rapid mechanisms can escape traditional analytical methods where only snapshots are obtained from highly dynamic events. Total internal reflection fluorescence (TIRF) microscopy is a powerful tool that can be used to investigate, in real-time, surface trafficking events at the single molecule level. The restricted excitation of fluorophores located at or near the plasma membrane in combination with high sensitivity quantitative cameras, makes it possible to record and analyze individual endocytic and recycling event in real time. In this chapter, we describe a TIRF microscopy protocol to investigate in real time, the ligand dependent MOR trafficking in Human Embryonic Kidney 293 cells and dissociated striatal neuronal cultures. This approach can provide unique spatio-temporal resolution to understand the fundamental events controlling MOR trafficking at the plasma membrane. PMID:25293317

  19. Real-time estimation of ionospheric delay using GPS measurements

    NASA Astrophysics Data System (ADS)

    Lin, Lao-Sheng

    1997-12-01

    When radio waves such as the GPS signals propagate through the ionosphere, they experience an extra time delay. The ionospheric delay can be eliminated (to the first order) through a linear combination of L1 and L2 observations from dual-frequency GPS receivers. Taking advantage of this dispersive principle, one or more dual- frequency GPS receivers can be used to determine a model of the ionospheric delay across a region of interest and, if implemented in real-time, can support single-frequency GPS positioning and navigation applications. The research objectives of this thesis were: (1) to develop algorithms to obtain accurate absolute Total Electron Content (TEC) estimates from dual-frequency GPS observables, and (2) to develop an algorithm to improve the accuracy of real-time ionosphere modelling. In order to fulfil these objectives, four algorithms have been proposed in this thesis. A 'multi-day multipath template technique' is proposed to mitigate the pseudo-range multipath effects at static GPS reference stations. This technique is based on the assumption that the multipath disturbance at a static station will be constant if the physical environment remains unchanged from day to day. The multipath template, either single-day or multi-day, can be generated from the previous days' GPS data. A 'real-time failure detection and repair algorithm' is proposed to detect and repair the GPS carrier phase 'failures', such as the occurrence of cycle slips. The proposed algorithm uses two procedures: (1) application of a statistical test on the state difference estimated from robust and conventional Kalman filters in order to detect and identify the carrier phase failure, and (2) application of a Kalman filter algorithm to repair the 'identified carrier phase failure'. A 'L1/L2 differential delay estimation algorithm' is proposed to estimate GPS satellite transmitter and receiver L1/L2 differential delays. This algorithm, based on the single-site modelling technique, is

  20. Real-Time Data-Acquisition Platform for Pulsed Measurements

    NASA Astrophysics Data System (ADS)

    Polyakov, Sergey V.; Migdall, Alan; Nam, Sae Woo

    2011-03-01

    We present an inexpensive and simple data acquisition platform based on Field Programmable Gate Arrays (FPGAs) designed to acquire and characterize fast digital or analog electrical signals in real time for processing on a generic personal computer. While the instrument was designed for electrical outputs of single-photon detectors and is suited for high photon-counting rates, it can also be used for characterization of similar digital electrical signals from other sources and for analog signals as well. The complete description of the platform is available for download at http://physics.nist.gov/fpga.

  1. A real-time colorimetric and ratiometric fluorescent probe for sulfite.

    PubMed

    Wu, Ming-Yu; He, Ting; Li, Kun; Wu, Ming-Bo; Huang, Zheng; Yu, Xiao-Qi

    2013-05-21

    A real-time colorimetric and ratiometric fluorescent probe based on modulating the intramolecular charge transfer (ICT) of the coumarin platform for selective detection of sulfite is presented. This reaction based probe utilized the Michael addition to the dicyano-vinyl group with the detection limit of 5.8 × 10(-5) M. The probe displayed a high selectivity for sulfite over other anions and reactive sulfur especially for biothiols including cysteine (Cys), homocysteine (Hcy) and glutathione (GSH), with about 100 nm blue shift and more than 230 times intensity ratios change of the emission spectrum. Meanwhile, it could be easily observed that the probe for sulfite changes from red to pale yellow by the naked eye, and from red to blue under UV lamp immediately after the sulfite is added. To the best of our knowledge, it is the fastest response probe for sulfite ever reported, which could give a colorimetric and ratiometric fluorescent response instantly. PMID:23563108

  2. Fluorescence particle detector for real-time quantification of viable organisms in air

    NASA Astrophysics Data System (ADS)

    Luoma, Greg; Cherrier, Pierre P.; Piccioni, Marc; Tanton, Carol; Herz, Steve; DeFreez, Richard K.; Potter, Michael; Girvin, Kenneth L.; Whitney, Ronald

    2002-02-01

    The ability to detect viable organisms in air in real time is important in a number of applications. Detecting high levels of airborne organisms in hospitals can prevent post-operative infections and the spread of diseases. Monitoring levels of airborne viable organisms in pharmaceutical facilities can ensure safe production of drugs or vaccines. Monitoring airborne bacterial levels in meat processing plants can help to prevent contamination of food products. Monitoring the level of airborne organisms in bio-containment facilities can ensure that proper procedures are being followed. Finally, detecting viable organisms in real time is a key to defending against biological agent attacks. This presentation describes the development and performance of a detector, based on fluorescence particle counting technology, where an ultraviolet laser is used to count particles by light scattering and elicit fluorescence from specific biomolecules found only in living organisms. The resulting detector can specifically detect airborne particles containing living organisms from among the large majority of other particles normally present in air. Efforts to develop the core sensor technology, focusing on integrating an UV laser with a specially designed particle-counting cell will be highlighted. The hardware/software used to capture the information from the sensor, provide an alarm in the presence of an unusual biological aerosol content will also be described. Finally, results from experiments to test the performance of the detector will be presented.

  3. Real-time Imaging of Tumor Progression in a Fluorescent Orthotopic Mouse Model of Thyroid Cancer

    PubMed Central

    TRAN CAO, HOP S.; KAUSHAL, SHARMEELA; SNYDER, CYNTHIA S.; ONGKEKO, WEG M.; HOFFMAN, ROBERT M.; BOUVET, MICHAEL

    2015-01-01

    There is a need for a clinically relevant mouse model of thyroid cancer that enables real-time, non-invasive monitoring of tumor growth, progression, and drug response over time. Human thyroid cancer cell lines NPA (papillary) and KAK-1 (anaplastic) were stably transfected to express either red or green fluorescent protein. Cancer cells were injected into the thyroid glands of 8-week-old athymic mice. The animals were imaged with whole-body fluorescence imaging weekly and sacrificed when premorbid. At necropsy, the primary tumor was resected en bloc with the respiratory system for processing and analysis. Histology was performed on fixed tissue specimens for review of morphologic findings. Both anaplastic and papillary thyroid cancer cell lines led to robust development of orthotopic fluorescent tumors in nude mice. Injection of 5×105 cancer cells was sufficient for tumor development. Tumors were visualized for both cell lines via non-invasive imaging as early as 3 weeks post-implantation and were monitored over time. Time to premorbid condition varied between mice and was associated with a primary tumor growth pattern (early local compression of the esophagus vs. late metastatic disease) rather than tumor size. At necropsy, tumor fluorescence demonstrated metastases in the lungs, lymph nodes and vessels that were not visible under white light. Thus an orthotopic mouse model of thyroid cancer has been developed that replicates the major clinical features of thyroid cancer and enables real-time, non-invasive monitoring of tumor progression. This model should permit preclinical evaluation of novel thyroid cancer therapeutics. PMID:21115887

  4. Assessment of Spectroscopic, Real-time Ion Thruster Grid Erosion-rate Measurements

    NASA Technical Reports Server (NTRS)

    Domonkos, Matthew T.; Stevens, Richard E.

    2000-01-01

    The success of the ion thruster on the Deep Space One mission has opened the gate to the use of primary ion propulsion. Many of the projected planetary missions require throughput and specific impulse beyond those qualified to date. Spectroscopic, real-time ion thruster grid erosion-rate measurements are currently in development at the NASA Glenn Research Center. A preliminary investigation of the emission spectra from an NSTAR derivative thruster with titanium grid was conducted. Some titanium lines were observed in the discharge chamber; however, the signals were too weak to estimate the erosion of the screen grid. Nevertheless, this technique appears to be the only non-intrusive real-time means to evaluate screen grid erosion, and improvement of the collection optics is proposed. Direct examination of the erosion species using laser-induced fluorescence (LIF) was determined to be the best method for a real-time accelerator grid erosion diagnostic. An approach for a quantitative LIF diagnostic was presented.

  5. Real-time measurements, rare events and photon economics

    NASA Astrophysics Data System (ADS)

    Jalali, B.; Solli, D. R.; Goda, K.; Tsia, K.; Ropers, C.

    2010-07-01

    Rogue events otherwise known as outliers and black swans are singular, rare, events that carry dramatic impact. They appear in seemingly unconnected systems in the form of oceanic rogue waves, stock market crashes, evolution, and communication systems. Attempts to understand the underlying dynamics of such complex systems that lead to spectacular and often cataclysmic outcomes have been frustrated by the scarcity of events, resulting in insufficient statistical data, and by the inability to perform experiments under controlled conditions. Extreme rare events also occur in ultrafast physical sciences where it is possible to collect large data sets, even for rare events, in a short time period. The knowledge gained from observing rare events in ultrafast systems may provide valuable insight into extreme value phenomena that occur over a much slower timescale and that have a closer connection with human experience. One solution is a real-time ultrafast instrument that is capable of capturing singular and randomly occurring non-repetitive events. The time stretch technology developed during the past 13 years is providing a powerful tool box for reaching this goal. This paper reviews this technology and discusses its use in capturing rogue events in electronic signals, spectroscopy, and imaging. We show an example in nonlinear optics where it was possible to capture rare and random solitons whose unusual statistical distribution resemble those observed in financial markets. The ability to observe the true spectrum of each event in real time has led to important insight in understanding the underlying process, which in turn has made it possible to control soliton generation leading to improvement in the coherence of supercontinuum light. We also show a new class of fast imagers which are being considered for early detection of cancer because of their potential ability to detect rare diseased cells (so called rogue cells) in a large population of healthy cells.

  6. Lysosome triggered near-infrared fluorescence imaging of cellular trafficking processes in real time

    PubMed Central

    Grossi, Marco; Morgunova, Marina; Cheung, Shane; Scholz, Dimitri; Conroy, Emer; Terrile, Marta; Panarella, Angela; Simpson, Jeremy C.; Gallagher, William M.; O'Shea, Donal F.

    2016-01-01

    Bioresponsive NIR-fluorophores offer the possibility for continual visualization of dynamic cellular processes with added potential for direct translation to in vivo imaging. Here we show the design, synthesis and lysosome-responsive emission properties of a new NIR fluorophore. The NIR fluorescent probe design differs from typical amine functionalized lysosomotropic stains with off/on fluorescence switching controlled by a reversible phenol/phenolate interconversion. Emission from the probe is shown to be highly selective for the lysosomes in co-imaging experiments using a HeLa cell line expressing the lysosomal-associated membrane protein 1 fused to green fluorescent protein. The responsive probe is capable of real-time continuous imaging of fundamental cellular processes such as endocytosis, lysosomal trafficking and efflux in 3D and 4D. The advantage of the NIR emission allows for direct translation to in vivo tumour imaging, which is successfully demonstrated using an MDA-MB-231 subcutaneous tumour model. This bioresponsive NIR fluorophore offers significant potential for use in live cellular and in vivo imaging, for which currently there is a deficit of suitable molecular fluorescent tools. PMID:26927507

  7. Lysosome triggered near-infrared fluorescence imaging of cellular trafficking processes in real time.

    PubMed

    Grossi, Marco; Morgunova, Marina; Cheung, Shane; Scholz, Dimitri; Conroy, Emer; Terrile, Marta; Panarella, Angela; Simpson, Jeremy C; Gallagher, William M; O'Shea, Donal F

    2016-01-01

    Bioresponsive NIR-fluorophores offer the possibility for continual visualization of dynamic cellular processes with added potential for direct translation to in vivo imaging. Here we show the design, synthesis and lysosome-responsive emission properties of a new NIR fluorophore. The NIR fluorescent probe design differs from typical amine functionalized lysosomotropic stains with off/on fluorescence switching controlled by a reversible phenol/phenolate interconversion. Emission from the probe is shown to be highly selective for the lysosomes in co-imaging experiments using a HeLa cell line expressing the lysosomal-associated membrane protein 1 fused to green fluorescent protein. The responsive probe is capable of real-time continuous imaging of fundamental cellular processes such as endocytosis, lysosomal trafficking and efflux in 3D and 4D. The advantage of the NIR emission allows for direct translation to in vivo tumour imaging, which is successfully demonstrated using an MDA-MB-231 subcutaneous tumour model. This bioresponsive NIR fluorophore offers significant potential for use in live cellular and in vivo imaging, for which currently there is a deficit of suitable molecular fluorescent tools. PMID:26927507

  8. Single DNA electrophoresis in Pluronic F127 in a real-time fluorescence microscopy

    NASA Astrophysics Data System (ADS)

    You, Seungyong; van Winkle, David

    2007-03-01

    Electrophoresis is the separation of bio-molecules in a sieving medium by applying an electric field. The Pluronic F127 gel was introduced as a new sieving medium for electrophoresis. The mobility of DNA in this gel is not fully explained by conventional reptation theories. Here, in our work, the migration of single DNA molecule pre-stained was studied on the gel electrophoresis by real-time fluorescence microscopy. Separations were performed on dsDNA fragments ranging in length from 200 base pairs (bp) to 2500 bp in pluronic gel in various concentrations. Evidence is presented that in some cases DNA fragments electrophorese along gel crystallite grain boundaries and in other cases directly through gel crystallites. This is direct observation of DNA migration through the pluronic gel on a microscopic scale.

  9. Initial formal toxicity evaluation of APC-2, a novel fluorescent tracer agent for real-time measurement of glomerular filtration rate in preparation for a first-in-man clinical trial

    NASA Astrophysics Data System (ADS)

    Bugaj, Joseph E.; Dorshow, Richard B.

    2014-03-01

    The fluorescent tracer agent 2,5-bis[N-(1-carboxy-2-hydroxy)]carbamoyl-3,6-diaminopyrazine, designated APC-2, has been developed with properties and attributes necessary for use as a direct measure of glomerular filtration rate (GFR). Comparison to known standard exogenous GFR agents in animal models has demonstrated an excellent correlation. A clinical trial to demonstrate this same correlation in humans is in preparation. A battery of formal toxicity tests necessary for regulatory clearance to proceed with a clinical trial has been recently completed on this new fluorescent tracer agent. These include single dose toxicity studies in rats and dogs to determine overall toxicity and toxicokinetics of the compound. Blood compatibility, mutation assay, chromosomal aberration assay, and several other assays were also completed. Toxicity assessments were based on mortality, clinical signs, body weight, food consumption and anatomical pathology. Blood samples were collected to assess pharmacokinetic parameters including half-life, area under the curve, and clearance. Urine samples were collected to assess distribution. Doses of up to 200-300 times the estimated human dose were administered. No test-article related effects were noted on body weight, food consumption, ophthalmic observations and no abnormal pathology was seen in either macroscopic or microscopic evaluations of any organs or tissues. All animals survived to scheduled sacrifice. Transient discoloration of skin and urine was noted at the higher dose levels in both species as expected from a highly fluorescent compound and was not considered pathological. Thus initial toxicology studies of this new fluorescent tracer agent APC-2 have resulted in no demonstrable pathological test article concerns.

  10. Wide-field near-infrared fluorescence endoscope for real-time in vivo imaging

    NASA Astrophysics Data System (ADS)

    Liu, Zhongyao; Miller, Sharon J.; Joshi, Bishnu P.; Wang, Thomas D.

    2012-02-01

    A diode-pumped solid state laser is used to deliver excitation at λex = 671 nm. The beam is expanded by a pair of relay lenses (f1 = 30 and f2 = 50 mm) to 3 mm diameter, filling the aperture of a fluid light cable that is coupled to a Hopkins II rigid endoscope. Near-infrared fluorescence images are collected by the endoscope and transmitted by another set of relay lenses onto a CCD detector that has dimensions of 8.7x6.9 mm2 (1388x1040 pixels). A zoom lens system (F#1.6-16 aperture) with a tunable focal length (20-100 mm) magnifies the image to fill the dimensions of the CCD. A band pass filter allows fluorescence with spectral range λem = 696 to 736 nm to be collected. The system achieves a resolution of 9.8 μm and field-of-view of 3.6 mm at a distance of 2.5 mm between the distal end of the endoscope and the tissue. Images are collected at a rate of 10 frames per second. A filter wheel is incorporated into the handle of the instrument housing to rapidly switch between reflectance and fluorescence images. Cy5.5-labeled peptides were delivered through the 1 mm diameter instrument channel in the endoscope. Near-infrared fluorescence images demonstrated specific peptide binding to spontaneous adenomas that developed beginning at 2 months of age in a genetically-engineered mouse with mutation of one allele in the APC gene. This integrated methodology represents a powerful tool that can achieve real time detection of disease in the colon and other hollow organs.

  11. Real-time Measurements of Amino Acid and Protein Hydroperoxides Using Coumarin Boronic Acid*

    PubMed Central

    Michalski, Radoslaw; Zielonka, Jacek; Gapys, Ewa; Marcinek, Andrzej; Joseph, Joy; Kalyanaraman, Balaraman

    2014-01-01

    Hydroperoxides of amino acid and amino acid residues (tyrosine, cysteine, tryptophan, and histidine) in proteins are formed during oxidative modification induced by reactive oxygen species. Amino acid hydroperoxides are unstable intermediates that can further propagate oxidative damage in proteins. The existing assays (oxidation of ferrous cation and iodometric assays) cannot be used in real-time measurements. In this study, we show that the profluorescent coumarin boronic acid (CBA) probe reacts with amino acid and protein hydroperoxides to form the corresponding fluorescent product, 7-hydroxycoumarin. 7-Hydroxycoumarin formation was catalase-independent. Based on this observation, we have developed a fluorometric, real-time assay that is adapted to a multiwell plate format. This is the first report showing real-time monitoring of amino acid and protein hydroperoxides using the CBA-based assay. This approach was used to detect protein hydroperoxides in cell lysates obtained from macrophages exposed to visible light and photosensitizer (rose bengal). We also measured the rate constants for the reaction between amino acid hydroperoxides (tyrosyl, tryptophan, and histidine hydroperoxides) and CBA, and these values (7–23 m−1 s−1) were significantly higher than that measured for H2O2 (1.5 m−1 s−1). Using the CBA-based competition kinetics approach, the rate constants for amino acid hydroperoxides with ebselen, a glutathione peroxidase mimic, were also determined, and the values were within the range of 1.1–1.5 × 103 m−1 s−1. Both ebselen and boronates may be used as small molecule scavengers of amino acid and protein hydroperoxides. Here we also show formation of tryptophan hydroperoxide from tryptophan exposed to co-generated fluxes of nitric oxide and superoxide. This observation reveals a new mechanism for amino acid and protein hydroperoxide formation in biological systems. PMID:24928516

  12. Research progress on real-time measurement of soil attributes for precision agriculture

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In order to develop a real-time analyzer for soil attributes, this study analyzed the needs for real-time measurement of soil attributes and reviewed major soil attributes to be measured in soil testing and commonly-used testing methods, including traditional chemical analysis, methods based on elec...

  13. Real-time Measurements of Biological Particles at Several Continental Sites using the WIBS-4A

    NASA Astrophysics Data System (ADS)

    McMeeking, G. R.; Kok, G. L.; Petters, M. D.; Wright, T.; Hader, J.; Mccubbin, I. B.; Hallar, A. G.; Twohy, C. H.; Toohey, D. W.; DeMott, P. J.; McCluskey, C.; Baumgardner, D.

    2013-12-01

    Biological particles (bacteria, fungi/fungal spores, viruses, algae and fragments of biological material) may play a significant role in modifying cloud properties by acting as ice nuclei and thus have an indirect effect on climate forcing. Little is known, however, regarding the abundance and distribution of biological particles and their importance to cloud microphysics in different environments. On-line, continuous measurement systems offer the potential to measure biological systems at high time resolution and sensitivity, providing greater insight into their distribution in the atmosphere, dispersal mechanisms and potential soures. The WIBS-4A (Wideband Integrated Bioaerosol Sensor) detects fluorescent biological material in real-time associated with individual particles. It measures five properties: a) optical size via light scattering, b) fluorescent emissions in the wavelength range 310-400 following excitation by 280 nm light, c) fluorescent emissions in the wavelength range 420-650 following excitation by 280 nm light, d) fluorescent emissions in the wavelength range 420-650 following excitation by 370 nm light, and e) particle asymmetry factor based on intensities of forward scattered light onto a 4-element detector. Together, these properties aid the classification of sampled particles that contain biofluorophores such as tryptophan or NAD(P)H, which can be found in biological particles. Here we present results from a series of laboratory, ground- and aircraft-based measurements of biological particles using the WIBS-4A. The studies include airborne measurements over the United States, ground-based measurements at a coastal site, an urban site in the southeast US and a high alpine site, and laboratory measurements of a variety of biological and non-biological particles. Our analysis focused on both the characterization of the instrument response as well as an evaluation of its suitability for performing ambient measurements and potential artifacts. We

  14. A REAL-TIME MEASURING DEVICE FOR DENSE PARTICULATE SYSTEMS

    EPA Science Inventory

    The report describes the design and performance of an instrument, based on the concept of instantaneous intensity ratio, for measuring particle size distributions of dense particulate matter. The method involves simultaneously measuring the intensity of light scattered by a parti...

  15. Real-Time Fluorescence Loop Mediated Isothermal Amplification for the Detection of Acinetobacter baumannii

    PubMed Central

    Wang, Qinqin; Zhou, Yanbin; Li, Shaoli; Zhuo, Chao; Xu, Siqi; Huang, Lixia; Yang, Ling; Liao, Kang

    2013-01-01

    Background Detection of Acinetobacter baumannii has been relying primarily on bacterial culture that often fails to return useful results in time. Although DNA-based assays are more sensitive than bacterial culture in detecting the pathogen, the molecular results are often inconsistent and challenged by doubts on false positives, such as those due to system- and environment-derived contaminations. In addition, these molecular tools require expensive laboratory instruments. Therefore, establishing molecular tools for field use require simpler molecular platforms. The loop-mediated isothermal amplification method is relatively simple and can be improved for better use in a routine clinical bacteriology laboratory. A simple and portable device capable of performing both the amplification and detection (by fluorescence) of LAMP in the same platform has been developed in recent years. This method is referred to as real-time loop-mediated isothermal amplification. In this study, we attempted to utilize this method for rapid detection of A. baumannii. Methodology and Significant Findings Species-specific primers were designed to test the utility of this method. Clinical samples of A. baumannii were used to determine the sensitivity and specificity of this system compared to bacterial culture and a polymerase chain reaction method. All positive samples isolated from sputum were confirmed to be the species of Acinetobacter by 16S rRNA gene sequencing. The RealAmp method was found to be simpler and allowed real-time detection of DNA amplification, and could distinguish A. baumannii from Acinetobacter calcoaceticus and Acinetobacter genomic species 3. DNA was extracted by simple boiling method. Compared to bacterial culture, the sensitivity and specificity of RealAmp in detecting A. baumannii was 98.9% and 75.0%, respectively. Conclusion The RealAmp assay only requires a single unit, and the assay positivity can be verified by visual inspection. Therefore, this assay has

  16. Technique for real-time tissue characterization based on scanning multispectral fluorescence lifetime spectroscopy (ms-TRFS)

    PubMed Central

    Ma, Dinglong; Bec, Julien; Gorpas, Dimitris; Yankelevich, Diego; Marcu, Laura

    2015-01-01

    We report a novel technique for continuous acquisition, processing and display of fluorescence lifetimes enabling real-time tissue diagnosis through a single hand held or biopsy fiber-optic probe. A scanning multispectral time-resolved fluorescence spectroscopy (ms-TRFS) with self-adjustable photon detection range was developed to account for the dynamic changes of fluorescence intensity typically encountered in clinical application. A fast algorithm was implemented in the ms-TRFS software platform, providing up to 15 Hz continuous display of fluorescence lifetime values. Potential applications of this technique, including biopsy guidance, and surgical margins delineation were demonstrated in proof-of-concept experiments. Current results showed accurate display of fluorescence lifetimes values and discrimination of distinct fluorescence markers and tissue types in real-time (< 100 ms per data point). PMID:25798320

  17. Real time swallowing measurement system by using photometric stereo

    NASA Astrophysics Data System (ADS)

    Fujino, Masahiro; Kato, Kunihito; Mura, Emi; Nagai, Hajime

    2015-04-01

    In this paper, we propose a measurement system to evaluate the swallowing by estimating the movement of the thyroid cartilage. We developed a measurement system based on the vision sensor in order to achieve the noncontact and non-invasive sensor. The movement of the subject's thyroid cartilage is tracked by the three dimensional information of the surface of the skin measured by the photometric stereo. We constructed a camera system that uses near-IR light sources and three camera sensors. We conformed the effectiveness of the proposed system by experiments.

  18. Error Correction for Foot Clearance in Real-Time Measurement

    NASA Astrophysics Data System (ADS)

    Wahab, Y.; Bakar, N. A.; Mazalan, M.

    2014-04-01

    Mobility performance level, fall related injuries, unrevealed disease and aging stage can be detected through examination of gait pattern. The gait pattern is normally directly related to the lower limb performance condition in addition to other significant factors. For that reason, the foot is the most important part for gait analysis in-situ measurement system and thus directly affects the gait pattern. This paper reviews the development of ultrasonic system with error correction using inertial measurement unit for gait analysis in real life measurement of foot clearance. This paper begins with the related literature where the necessity of measurement is introduced. Follow by the methodology section, problem and solution. Next, this paper explains the experimental setup for the error correction using the proposed instrumentation, results and discussion. Finally, this paper shares the planned future works.

  19. Real-time precision measuring device of tree diameter growth

    NASA Astrophysics Data System (ADS)

    Guo, Mingming; Chen, Aijun; Li, Dongsheng; Liu, Nan; Yao, Jingyuan

    2016-01-01

    DBH(diameter at breast height) is an important factor to reflect of the quality of plant growth, also an important parameter indispensable in forest resources inventory and forest carbon sink, the accurate measurement of DBH or not is directly related to the research of forest resources inventory and forest carbon sink. In this paper, the principle and the mathematical model of DBH measurement device were introduced, the fixture measuring device and the hardware circuit for this tree diameter were designed, the measurement software programs were compiled, and the precision measuring device of tree diameter growth was developed. Some experiments with Australia fir were conducted. Based on experiment data, the correlations among the DBH variation of Australian fir, the environment temperature, air humility and PAR(photosynthetically active radiation) were obtained. The effects of environmental parameters (environment temperature, air humility and PAR) on tree diameter were analyzed. Experimental results show that there is a positive correlation between DBH variation of Australian fir and environment temperature, a negative correlation between DBH variation of Australian fir and air humility , so is PAR.

  20. Real-time measurement of engine oil economy

    SciTech Connect

    Butler, J.W.; Korniski, T.; Calvin, A.D.; Jary, E.H.

    1987-01-01

    A coulometric SO/sub 2/ monitor has been developed to measure SO/sub 2/ generated from combustion of S in oil to determine engine oil consumption. Sulfur-free fuel is used to eliminate background levels of SO/sub 2/. Addition of an SO/sub 2/ standard gas to the engine during test insures accurate normalization of sampling system flows and quantitative measurement of engine oil economy. Precision of the SO/sub 2/ microcoulometer technique was better than +-8%. The SO/sub 2/ microcoulometer is used during steady state engine operation, and may be used in determining oil consumption from individual cylinders. Existence of engine oil consumption via an aerosol mechanism is investigated and measured. Effects of engine operating temperature and positive crankcase ventilation (PCV) on engine oil economy are given.

  1. IN SITU Device for Real-Time Catalyst Deactivation Measurements

    SciTech Connect

    Fossil Energy Research

    2008-03-31

    SCR catalyst management has become an important operations and maintenance activity for coal-fired utility boilers in the United States. To facilitate this activity, a method to determine Catalyst Activity in situ is being developed. This report describes the methodology and presents the results of a two ozone season demonstration conducted at Alabama Power Company's Gorgas Unit 10 during the 2005 and 2006 ozone seasons. The results showed that the in situ measurements are in good agreement with the laboratory measurements and the technique has some advantages over the traditional laboratory method of determining Catalyst Activity and Reactor Potential. SCR Performance is determined by the overall Reactor Potential (the product of the Catalyst Activity and the available surface area per unit of flue gas). The in situ approach provides a direct measurement of Reactor Potential under actual operating conditions, whereas laboratory measurements of Catalyst Activity need to be coupled with estimates of catalyst pluggage and flue gas flowrate in order to assess Reactor Potential. The project also showed that the in situ activity results can easily be integrated into catalyst management software to aid in making informed catalyst decisions.

  2. Adaptive, real-time hypoxia measurements using an autonomous boat

    NASA Astrophysics Data System (ADS)

    Kerkez, B.; Wong, B. P.; Balzano, L.; Lipor, J.; Scavia, D.

    2015-12-01

    We present an autonomous system to measure hypoxia at high spatial resolutions. The approach combines a robotic boat, cloud hosted data services, and a suite of adaptive sampling algorithms to minimize the number of samples required to delineate hypoxic extents. The boat lowers sensors into the water column to provide depth profiles of temperature and oxygen concentrations. An adaptive path-planning algorithm continuously analyzes the in-situ observations and directs the boat to its next measurement location. This significantly reduces number of samples compared to a gridded sampling approach, while simultaneously improving the certainty with which the hypoxic regions are delineated. The method has been evaluated on small lakes throughout Michigan and shows significant promise to scale to the Great Lakes, where hypoxia is common occurrence that adversely affects various stakeholder and ecosystems.

  3. Hilbert phase dynamometry (HPD) for real-time measurement of cell generated forces (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Sridharan, Shamira; Li, Yanfen; Bhaduri, Basanta; Majeed, Hassaan; Dupenloup, Paul; Levine, Alex; Kilian, Kristopher A.; Popescu, Gabriel

    2016-03-01

    Traction force microscopy is the most widely used technique for studying the forces exerted by cells on deformable substrates. However, the method is computationally intense and cells have to be detached from the substrate prior to measuring the displacement map. We have developed a new method, referred to as Hilbert phase dynamometry (HPD), which yields real-time force fields and, simultaneously, cell dry mass and growth information. HPD operates by imaging cells on a deformable substrate that is patterned with a grid of fluorescent proteins. A Hilbert transform is used to extract the phase map associated with the grid deformation, which provides the displacement field. By combining this information with substrate stiffness, an elasticity model was developed to measure forces exerted by cells with high spatial resolution. In our study, we prepared 10kPa gels and them with a 2-D grid of FITC-conjugated fibrinogen/fibronectin mixture, an extracellular matrix protein to which cells adhere. We cultured undifferentiated mesenchymal stem cells (MSC), and MSCs that were in the process of undergoing adipogenesis and osteogenesis. The cells were measured over the course of 24 hours using Spatial Light Interference Microscopy (SLIM) and wide-field epi-fluorescence microscopy allowing us to simultaneously measure cell growth and the forces exerted by the cells on the substrate.

  4. Real Time Turbulence Estimation Using Doppler Lidar Measurements

    NASA Astrophysics Data System (ADS)

    Rottner, Lucie; Baehr, Christophe

    2016-06-01

    A preliminary work on a new way to estimate atmospheric turbulence using high-frequency Doppler lidar measurements is presented. The turbulence estimations are based on wind reconstruction using 3D Doppler lidar observations and a particle filter. The suggested reconstruction algorithm links the lidar observations to numerical particles to obtain turbulence estimations every time new observations are available. The high frequency of the estimations is a new point which is detailed and discussed. Moreover, the presented algorithm ables to reconstruct the wind in three dimensions in the observed volume. We have thus locally access to the spatial variability of the turbulent atmosphere. The suggested algorithm is applied to a set of real observations. The obtained results are very encouraging : they show significant improvements on turbulent parameter estimations.

  5. Fluorescence interference contrast based approach to study real time interaction of melittin with plasma membranes

    NASA Astrophysics Data System (ADS)

    Gupta, Sharad; Gui, Dong; Zandi, Roya; Gill, Sarjeet; Mohideen, Umar

    2014-03-01

    Melittin is an anti-bacterial and hemolytic toxic peptide found in bee venom. Cell lysis behavior of peptides has been widely investigated, but the exact interaction mechanism of lytic peptides with lipid membranes and its constituents has not been understood completely. In this paper we study the melittin interaction with lipid plasma membranes in real time using non-invasive and non-contact fluorescence interference contrast microscopy (FLIC). Particularly the interaction of melittin with plasma membranes was studied in a controlled molecular environment, where these plasma membrane were composed of saturated lipid, 1,2-diphytanoyl-sn-glycero-3-phosphocholine (DPhPC) and unsaturated lipid, 1,2-dioleoyl-sn-glycero-3-phosphocholine(DOPC) with and without cholesterol. We found out that melittin starts to form nanometer size pores in the plasma membranes shortly after interacting with membranes. But the addition of cholesterol in plasma membrane slows down the pore formation process. Our results show that inclusion of cholesterol to the plasma membranes make them more resilient towards pore formation and lysis of membrane.

  6. Real-time Monitoring of Ligand-receptor Interactions with Fluorescence Resonance Energy Transfer

    PubMed Central

    Dogra, Navneet; Reyes, Julia C.; Garg, Nishi; Kohli, Punit

    2012-01-01

    FRET is a process whereby energy is non-radiatively transferred from an excited donor molecule to a ground-state acceptor molecule through long-range dipole-dipole interactions1. In the present sensing assay, we utilize an interesting property of PDA: blue-shift in the UV-Vis electronic absorption spectrum of PDA (Figure 1) after an analyte interacts with receptors attached to PDA2,3,4,7. This shift in the PDA absorption spectrum provides changes in the spectral overlap (J) between PDA (acceptor) and rhodamine (donor) that leads to changes in the FRET efficiency. Thus, the interactions between analyte (ligand) and receptors are detected through FRET between donor fluorophores and PDA. In particular, we show the sensing of a model protein molecule streptavidin. We also demonstrate the covalent-binding of bovine serum albumin (BSA) to the liposome surface with FRET mechanism. These interactions between the bilayer liposomes and protein molecules can be sensed in real-time. The proposed method is a general method for sensing small chemical and large biochemical molecules. Since fluorescence is intrinsically more sensitive than colorimetry, the detection limit of the assay can be in sub-nanomolar range or lower8. Further, PDA can act as a universal acceptor in FRET, which means that multiple sensors can be developed with PDA (acceptor) functionalized with donors and different receptors attached on the surface of PDA liposomes. PMID:22929922

  7. Real-Time Intraoperative Near-Infrared Fluorescence Identification of the Extrahepatic Bile Ducts using Clinically-Available Contrast Agents

    PubMed Central

    Matsui, Aya; Tanaka, Eiichi; Choi, Hak Soo; Winer, Joshua H.; Kianzad, Vida; Gioux, Sylvain; Laurence, Rita G.; Frangioni, John V.

    2009-01-01

    Background Iatrogenic bile duct injuries are serious complications with patient morbidity. We hypothesized that the invisible near-infrared (NIR) fluorescence properties of methylene blue (MB) and indocyanine green (ICG) could be exploited for real-time, intraoperative imaging of the extrahepatic bile ducts during open and laparoscopic surgeries. Methods 2.0 mg/kg of MB and 0.05 mg/kg of ICG were intravenously injected into 35-kg female Yorkshire pigs and the extrahepatic bile ducts imaged over time using either the FLARE™ image-guided surgery system (open surgery) or a custom NIR fluorescence laparoscopy system. Surgical anatomy was confirmed using x-ray cholangiography. Contrast-to-background ratio (CBR), contrast-to-liver ratio (CLR), and chemical concentrations in the cystic duct (CD) and common bile duct (CBD) were measured, and the performance of each agent quantified. Results Using NIR fluorescence of MB, the CD and CBD could be identified with good sensitivity (CBR and CLR ≥ 4), during both open and laparoscopic surgeries, from 10 to 120 min post-injection. Functional impairment of the ducts, including constriction and injury were immediately identifiable. Using NIR fluorescence of ICG, extrahepatic bile ducts did not become visible until 90 min post-injection due to strong residual liver retention, however, between 90 to 240 min, ICG provided exquisitely high sensitivity for both CD and CBD, with CBR ≥ 8 and CLR ≥ 4. Conclusions We demonstrate that two clinically available NIR fluorophores, MB fluorescing at 700 nm and ICG fluorescing at 800 nm, provide sensitive, prolonged identification of the extrahepatic bile ducts and assessment of their functional status. PMID:20117813

  8. Fluorescent Single-Stranded DNA Binding Protein as a Probe for Sensitive, Real-Time Assays of Helicase Activity

    PubMed Central

    Dillingham, Mark S.; Tibbles, Katherine L.; Hunter, Jackie L.; Bell, Jason C.; Kowalczykowski, Stephen C.; Webb, Martin R.

    2008-01-01

    The formation and maintenance of single-stranded DNA (ssDNA) are essential parts of many processes involving DNA. For example, strand separation of double-stranded DNA (dsDNA) is catalyzed by helicases, and this exposure of the bases on the DNA allows further processing, such as replication, recombination, or repair. Assays of helicase activity and probes for their mechanism are essential for understanding related biological processes. Here we describe the development and use of a fluorescent probe to measure ssDNA formation specifically and in real time, with high sensitivity and time resolution. The reagentless biosensor is based on the ssDNA binding protein (SSB) from Escherichia coli, labeled at a specific site with a coumarin fluorophore. Its use in the study of DNA manipulations involving ssDNA intermediates is demonstrated in assays for DNA unwinding, catalyzed by DNA helicases. PMID:18599625

  9. SNSMIL, a real-time single molecule identification and localization algorithm for super-resolution fluorescence microscopy

    PubMed Central

    Tang, Yunqing; Dai, Luru; Zhang, Xiaoming; Li, Junbai; Hendriks, Johnny; Fan, Xiaoming; Gruteser, Nadine; Meisenberg, Annika; Baumann, Arnd; Katranidis, Alexandros; Gensch, Thomas

    2015-01-01

    Single molecule localization based super-resolution fluorescence microscopy offers significantly higher spatial resolution than predicted by Abbe’s resolution limit for far field optical microscopy. Such super-resolution images are reconstructed from wide-field or total internal reflection single molecule fluorescence recordings. Discrimination between emission of single fluorescent molecules and background noise fluctuations remains a great challenge in current data analysis. Here we present a real-time, and robust single molecule identification and localization algorithm, SNSMIL (Shot Noise based Single Molecule Identification and Localization). This algorithm is based on the intrinsic nature of noise, i.e., its Poisson or shot noise characteristics and a new identification criterion, QSNSMIL, is defined. SNSMIL improves the identification accuracy of single fluorescent molecules in experimental or simulated datasets with high and inhomogeneous background. The implementation of SNSMIL relies on a graphics processing unit (GPU), making real-time analysis feasible as shown for real experimental and simulated datasets. PMID:26098742

  10. AUTOMATED CONTROL AND REAL-TIME DATA PROCESSING OF WIRE SCANNER/HALO SCRAPER MEASUREMENTS

    SciTech Connect

    L.A. DAY; J.D. GILPATRICK; ET AL

    2001-06-01

    The Low-Energy Demonstration Accelerator (LEDA), assembled and operating at Los Alamos National Laboratory, provides the platform for obtaining measurements of high-power proton beam-halo formation. Control system software and hardware have been integrated and customized to enable the production of real-time beam-halo profiles. The Experimental Physics and Industrial Control System (EPICS) hosted on a VXI platform, Interactive Data Language (IDL) programs hosted on UNIX platforms, and LabVIEW (LV) Virtual Instruments hosted on a PC platform have been integrated and customized to provide real-time, synchronous motor control, data acquisition, and data analysis of data acquired through specialized DSP instrumentation. These modules communicate through EPICS Channel Access (CA) communication protocol extensions to control and manage execution flow ensuring synchronous data acquisition and real-time processing of measurement data. This paper describes the software integration and management scheme implemented to produce these real-time beam profiles.

  11. Real time in vivo investigation of superoxide dynamics in zebrafish liver using a single-fiber fluorescent probe

    PubMed Central

    Chang, Yu-Chung; Ken, Chuian-Fu; Hsu, Che-Wei; Liu, Ya-Ging

    2013-01-01

    Superoxide anion is the key radical that causes intracellular oxidative stress. The lack of a method to directly monitor superoxide concentration in vivo in real time has severely hindered our understanding on its pathophysiology. We made transgenic zebrafish to specifically express yellow fluorescent proteins, a reversible superoxide-specific indicator, in the liver and used a fiber-optic fluorescent probe to noninvasively monitor the superoxide concentration in real time. Several superoxide-inducing and scavenging reagents were administrated onto the fish to alter superoxide concentrations. The distinct biochemical pathways of the reagents can be discerned from the transient behaviors of fluorescence time courses. These results demonstrate the feasibility of this method for analyzing superoxide dynamics and its potential as an in vivo pharmaceutical screening platform. PMID:24049691

  12. Real-time hyperspectral fluorescence imaging of pancreatic β-cell dynamics with the image mapping spectrometer

    PubMed Central

    Elliott, Amicia D.; Gao, Liang; Ustione, Alessandro; Bedard, Noah; Kester, Robert; Piston, David W.; Tkaczyk, Tomasz S.

    2012-01-01

    Summary The development of multi-colored fluorescent proteins, nanocrystals and organic fluorophores, along with the resulting engineered biosensors, has revolutionized the study of protein localization and dynamics in living cells. Hyperspectral imaging has proven to be a useful approach for such studies, but this technique is often limited by low signal and insufficient temporal resolution. Here, we present an implementation of a snapshot hyperspectral imaging device, the image mapping spectrometer (IMS), which acquires full spectral information simultaneously from each pixel in the field without scanning. The IMS is capable of real-time signal capture from multiple fluorophores with high collection efficiency (∼65%) and image acquisition rate (up to 7.2 fps). To demonstrate the capabilities of the IMS in cellular applications, we have combined fluorescent protein (FP)-FRET and [Ca2+]i biosensors to measure simultaneously intracellular cAMP and [Ca2+]i signaling in pancreatic β-cells. Additionally, we have compared quantitatively the IMS detection efficiency with a laser-scanning confocal microscope. PMID:22854044

  13. Glowing clay: Real time tracing using a suite of novel clay based fluorescent tracers

    NASA Astrophysics Data System (ADS)

    Hardy, Robert; Quinton, John; Pates, Jackie; Coogan, Mike

    2015-04-01

    Clay is one of the most mobile fractions of soil due to its small particle size. It is also known to sorb many chemicals, such as nutrients (notably phosphorus), agrochemicals and heavy metals. The movement of clay is therefore linked with the transport and fate of these substances. A novel fluorescent clay tracing suite has been produced, together with an imaging technique. This suite consists of qualitative clay tracers, using rhodamine based fluorophores, and quantitative clay tracers, using metal based fluorophores. Efforts have also been made to allow integration of commercially available tracers, which are silt and sand sized. The clay tracers exploit the high affinity that montmorillonite has for Rhodamine B and Ru(bpy)3. This allows for an extremely thin layer of the fluorophore to be sorbed onto the clay's surface, in much that same way as materials in the natural environment will bind to clay. The tracer that is produced retains key chemical and physical properties of clay, such as size, shape and density. The retention of these micro-properties results in the retention of macro-properties, such as tendency to aggregate and cracking on drying. Imaging techniques have been developed to analyse these tracers. The imaging system uses diffused laser light to excite the tracer and a modified DSLR camera to image the soil surface. The images have been compiled into a time lapse video showing the movement of clay over the course of a rainfall event. This is the first time that the quantitative movement of clay has been recorded over a soil surface in real time. 4D data can be extracted from the images allowing the spatial location and intensity of tracer to be monitored over time, with mm precision and on the timescale of seconds. As the system can also work with a commercial tracer it is possible to investigate the movement of particles of almost any size and over a range of scales from soil box to hillside. This allows users to access this technique without

  14. Real-time measurements to characterize dynamics of emulsion interface during simulated intestinal digestion.

    PubMed

    Pan, Yuanjie; Nitin, N

    2016-05-01

    Efficient delivery of bioactives remains a critical challenge due to their limited bioavailability and solubility. While many encapsulation systems are designed to modulate the digestion and release of bioactives within the human gastrointestinal tract, there is limited understanding of how engineered structures influence the delivery of bioactives. The objective of this study was to develop a real-time quantitative method to measure structural changes in emulsion interface during simulated intestinal digestion and to correlate these changes with the release of free fatty acids (FFAs). Fluorescence resonant energy transfer (FRET) was used for rapid in-situ measurement of the structural changes in emulsion interface during simulated intestinal digestion. By using FRET, changes in the intermolecular spacing between the two different fluorescent probes labeled emulsifier were characterized. Changes in FRET measurements were compared with the release of FFAs. The results showed that bile salts and pancreatic lipase interacted immediately with the emulsion droplets and disrupted the emulsion interface as evidenced by reduction in FRET efficacy compared to the control. Similarly, a significant amount of FFAs was released during digestion. Moreover, addition of a second layer of polymers at emulsion interface decreased the extent of interface disruption by bile salts and pancreatic lipase and impacted the amount or rate of FFA release during digestion. These results were consistent with the lower donor/acceptor ratio of the labeled probes from the FRET result. Overall, this study provides a novel approach to analyze the dynamics of emulsion interface during digestion and their relationship with the release of FFAs. PMID:26854582

  15. Method and apparatus for real-time measurement of fuel gas compositions and heating values

    DOEpatents

    Zelepouga, Serguei; Pratapas, John M.; Saveliev, Alexei V.; Jangale, Vilas V.

    2016-03-22

    An exemplary embodiment can be an apparatus for real-time, in situ measurement of gas compositions and heating values. The apparatus includes a near infrared sensor for measuring concentrations of hydrocarbons and carbon dioxide, a mid infrared sensor for measuring concentrations of carbon monoxide and a semiconductor based sensor for measuring concentrations of hydrogen gas. A data processor having a computer program for reducing the effects of cross-sensitivities of the sensors to components other than target components of the sensors is also included. Also provided are corresponding or associated methods for real-time, in situ determination of a composition and heating value of a fuel gas.

  16. Real-time remote detection and measurement for airborne imaging spectroscopy: a case study with methane

    NASA Astrophysics Data System (ADS)

    Thompson, D. R.; Leifer, I.; Bovensmann, H.; Eastwood, M.; Fladeland, M.; Frankenberg, C.; Gerilowski, K.; Green, R. O.; Kratwurst, S.; Krings, T.; Luna, B.; Thorpe, A. K.

    2015-06-01

    Localized anthropogenic sources of atmospheric CH4 are highly uncertain and temporally variable. Airborne remote measurement is an effective method to detect and quantify these emissions. In a campaign context, the science yield can be dramatically increased by real-time retrievals that allow operators to coordinate multiple measurements of the most active areas. This can improve science outcomes for both single- and multiple-platform missions. We describe a case study of the NASA/ESA CO2 and Methane Experiment (COMEX) campaign in California during June and August/September 2014. COMEX was a multi-platform campaign to measure CH4 plumes released from anthropogenic sources including oil and gas infrastructure. We discuss principles for real-time spectral signature detection and measurement, and report performance on the NASA Next Generation Airborne Visible Infrared Spectrometer (AVIRIS-NG). AVIRIS-NG successfully detected CH4 plumes in real-time at Gb s-1 data rates, characterizing fugitive releases in concert with other in situ and remote instruments. The teams used these real-time CH4 detections to coordinate measurements across multiple platforms, including airborne in situ, airborne non-imaging remote sensing, and ground-based in situ instruments. To our knowledge this is the first reported use of real-time trace gas signature detection in an airborne science campaign, and presages many future applications.

  17. Bioinspired fluorescent dipeptide nanoparticles for targeted cancer cell imaging and real-time monitoring of drug release

    NASA Astrophysics Data System (ADS)

    Fan, Zhen; Sun, Leming; Huang, Yujian; Wang, Yongzhong; Zhang, Mingjun

    2016-04-01

    Peptide nanostructures are biodegradable and are suitable for many biomedical applications. However, to be useful imaging probes, the limited intrinsic optical properties of peptides must be overcome. Here we show the formation of tryptophan–phenylalanine dipeptide nanoparticles (DNPs) that can shift the peptide's intrinsic fluorescent signal from the ultraviolet to the visible range. The visible emission signal allows the DNPs to act as imaging and sensing probes. The peptide design is inspired by the red shift seen in the yellow fluorescent protein that results from π–π stacking and by the enhanced fluorescence intensity seen in the green fluorescent protein mutant, BFPms1, which results from the structure rigidification by Zn(II). We show that DNPs are photostable, biocompatible and have a narrow emission bandwidth and visible fluorescence properties. DNPs functionalized with the MUC1 aptamer and doxorubicin can target cancer cells and can be used to image and monitor drug release in real time.

  18. Cancer cell-targeted two-photon fluorescence probe for the real-time ratiometric imaging of DNA damage.

    PubMed

    Zhang, Hua; Wang, Kui; Xuan, Xiaopeng; Lv, Qingzhang; Nie, Yamin; Guo, Haiming

    2016-05-01

    Real-time imaging of DNA damage in cancer cells could provide valuable information on the formation and development of cancer. Herein, a two-photon fluorescence probe was discovered. Through sequential ICT processes, it allows successful in vivo visualization of DNA damage in cancer cells by one/two-photon microscopic imaging or by the unaided eye and a hand-held ultraviolet lamp. PMID:27087314

  19. Real-time intermembrane force measurements and imaging of lipid domain morphology during hemifusion

    NASA Astrophysics Data System (ADS)

    Lee, Dong Woog; Kristiansen, Kai; Donaldson, Stephen H., Jr.; Cadirov, Nicholas; Banquy, Xavier; Israelachvili, Jacob N.

    2015-05-01

    Membrane fusion is the core process in membrane trafficking and is essential for cellular transport of proteins and other biomacromolecules. During protein-mediated membrane fusion, membrane proteins are often excluded from the membrane-membrane contact, indicating that local structural transformations in lipid domains play a major role. However, the rearrangements of lipid domains during fusion have not been thoroughly examined. Here using a newly developed Fluorescence Surface Forces Apparatus (FL-SFA), migration of liquid-disordered clusters and depletion of liquid-ordered domains at the membrane-membrane contact are imaged in real time during hemifusion of model lipid membranes, together with simultaneous force-distance and lipid membrane thickness measurements. The load and contact time-dependent hemifusion results show that the domain rearrangements decrease the energy barrier to fusion, illustrating the significance of dynamic domain transformations in membrane fusion processes. Importantly, the FL-SFA can unambiguously correlate interaction forces and in situ imaging in many dynamic interfacial systems.

  20. Real-time intermembrane force measurements and imaging of lipid domain morphology during hemifusion

    PubMed Central

    Lee, Dong Woog; Kristiansen, Kai; Donaldson, Jr., Stephen H.; Cadirov, Nicholas; Banquy, Xavier; Israelachvili, Jacob N.

    2015-01-01

    Membrane fusion is the core process in membrane trafficking and is essential for cellular transport of proteins and other biomacromolecules. During protein-mediated membrane fusion, membrane proteins are often excluded from the membrane–membrane contact, indicating that local structural transformations in lipid domains play a major role. However, the rearrangements of lipid domains during fusion have not been thoroughly examined. Here using a newly developed Fluorescence Surface Forces Apparatus (FL-SFA), migration of liquid-disordered clusters and depletion of liquid-ordered domains at the membrane–membrane contact are imaged in real time during hemifusion of model lipid membranes, together with simultaneous force–distance and lipid membrane thickness measurements. The load and contact time-dependent hemifusion results show that the domain rearrangements decrease the energy barrier to fusion, illustrating the significance of dynamic domain transformations in membrane fusion processes. Importantly, the FL-SFA can unambiguously correlate interaction forces and in situ imaging in many dynamic interfacial systems. PMID:26006266

  1. Fluorescence-based enhanced reality (FLER) for real-time estimation of bowel perfusion in minimally invasive surgery

    NASA Astrophysics Data System (ADS)

    Diana, Michele

    2016-03-01

    Pre-anastomotic bowel perfusion is a key factor for a successful healing process. Clinical judgment has limited accuracy to evaluate intestinal microperfusion. Fluorescence videography is a promising tool for image-guided intraoperative assessment of the bowel perfusion at the future anastomotic site in the setting of minimally invasive procedures. The standard configuration for fluorescence videography includes a Near-Infrared endoscope able to detect the signal emitted by a fluorescent dye, more frequently Indocyanine Green (ICG), which is administered by intravenous injection. Fluorescence intensity is proportional to the amount of fluorescent dye diffusing in the tissue and consequently is a surrogate marker of tissue perfusion. However, fluorescence intensity alone remains a subjective approach and an integrated computer-based analysis of the over-time evolution of the fluorescence signal is required to obtain quantitative data. We have developed a solution integrating computer-based analysis for intra-operative evaluation of the optimal resection site, based on the bowel perfusion as determined by the dynamic fluorescence intensity. The software can generate a "virtual perfusion cartography", based on the "fluorescence time-to-peak". The virtual perfusion cartography can be overlapped onto real-time laparoscopic images to obtain the Enhanced Reality effect. We have defined this approach FLuorescence-based Enhanced Reality (FLER). This manuscript describes the stepwise development of the FLER concept.

  2. Real-time quantitation of Cu(II) by a fluorescence-based biosensing approach

    NASA Astrophysics Data System (ADS)

    Thompson, Richard B.; Zeng, Hui-Hui; Maliwal, Badri P.; Fierke, Carol A.

    2001-05-01

    Recently, there has been substantial interest in reducing the levels of toxic heavy metals in wastewater effluents from activities such as shipyards. Of particular interest is copper, which comprises tens of percent by weight of the hundreds of pounds of antifouling paint coating the bottom of a large vessel, but which is toxic to commercially important shellfish at sub-part per billion levels. As a result wastewater effluents must be monitored closely with sensor(s) capable of rapidly and accurately detecting excess copper in time to prevent release. We have pursued a fluorescence-based biosensing approach to obtain sub-ppb sensitivity for Cu(II) and immunity from interference from other cations abundant in sea water, such as Ca, Mg, and Sr. Our approach uses a protein, apocarbonic anhydrase II, as a very sensitive and selective ligand for Cu(II) which transduces the (reversible) binding of the metal as a change in fluorescence intensity, lifetime, or anisotropy, the first two of which may be conveniently measured through optical fiber. Thus we have been able to measure sub-ppb levels of Cu added to sea water, and to characterize the speciation of the Cu(II) to some degree, due to the presence of other ligands.

  3. An optical real-time 3D measurement for analysis of facial shape and movement

    NASA Astrophysics Data System (ADS)

    Zhang, Qican; Su, Xianyu; Chen, Wenjing; Cao, Yiping; Xiang, Liqun

    2003-12-01

    Optical non-contact 3-D shape measurement provides a novel and useful tool for analysis of facial shape and movement in presurgical and postsurgical regular check. In this article we present a system, which allows a precise 3-D visualization of the patient's facial before and after craniofacial surgery. We discussed, in this paper, the real time 3-D image capture, processing and the 3-D phase unwrapping method to recover complex shape deformation when the movement of the mouth. The result of real-time measurement for facial shape and movement will be helpful for the more ideal effect in plastic surgery.

  4. Real-time measurements of the largest Lyapunov exponent in optical fields

    NASA Astrophysics Data System (ADS)

    Gavrylyak, M. S.; Maksimyak, P. P.

    2012-01-01

    An analog interference method for measuring the largest Lyapunov exponent in optical fields generated by scattering objects and mediums is proposed. The method is used to make a device for high-speed real time transverse correlation function optical fields measurement.

  5. Real-time measurements of the largest Lyapunov exponent in optical fields

    NASA Astrophysics Data System (ADS)

    Gavrylyak, M. S.; Maksimyak, P. P.

    2011-09-01

    An analog interference method for measuring the largest Lyapunov exponent in optical fields generated by scattering objects and mediums is proposed. The method is used to make a device for high-speed real time transverse correlation function optical fields measurement.

  6. High-resolution, real-time simultaneous 3D surface geometry and temperature measurement.

    PubMed

    An, Yatong; Zhang, Song

    2016-06-27

    This paper presents a method to simultaneously measure three-dimensional (3D) surface geometry and temperature in real time. Specifically, we developed 1) a holistic approach to calibrate both a structured light system and a thermal camera under exactly the same world coordinate system even though these two sensors do not share the same wavelength; and 2) a computational framework to determine the sub-pixel corresponding temperature for each 3D point as well as discard those occluded points. Since the thermal 2D imaging and 3D visible imaging systems do not share the same spectrum of light, they can perform sensing simultaneously in real time: we developed a hardware system that can achieve real-time 3D geometry and temperature measurement at 26 Hz with 768 × 960 points per frame. PMID:27410608

  7. Real-time MSE measurements for current profile control on KSTAR.

    PubMed

    De Bock, M F M; Aussems, D; Huijgen, R; Scheffer, M; Chung, J

    2012-10-01

    To step up from current day fusion experiments to power producing fusion reactors, it is necessary to control long pulse, burning plasmas. Stability and confinement properties of tokamak fusion reactors are determined by the current or q profile. In order to control the q profile, it is necessary to measure it in real-time. A real-time motional Stark effect diagnostic is being developed at Korean Superconducting Tokamak for Advanced Research for this purpose. This paper focuses on 3 topics important for real-time measurements: minimize the use of ad hoc parameters, minimize external influences and a robust and fast analysis algorithm. Specifically, we have looked into extracting the retardance of the photo-elastic modulators from the signal itself, minimizing the influence of overlapping beam spectra by optimizing the optical filter design and a multi-channel, multiharmonic phase locking algorithm. PMID:23126864

  8. Real-time MSE measurements for current profile control on KSTAR

    SciTech Connect

    De Bock, M. F. M.; Aussems, D.; Huijgen, R.; Scheffer, M.; Chung, J.

    2012-10-15

    To step up from current day fusion experiments to power producing fusion reactors, it is necessary to control long pulse, burning plasmas. Stability and confinement properties of tokamak fusion reactors are determined by the current or q profile. In order to control the q profile, it is necessary to measure it in real-time. A real-time motional Stark effect diagnostic is being developed at Korean Superconducting Tokamak for Advanced Research for this purpose. This paper focuses on 3 topics important for real-time measurements: minimize the use of ad hoc parameters, minimize external influences and a robust and fast analysis algorithm. Specifically, we have looked into extracting the retardance of the photo-elastic modulators from the signal itself, minimizing the influence of overlapping beam spectra by optimizing the optical filter design and a multi-channel, multiharmonic phase locking algorithm.

  9. Real-time phase measurement of optical vortices based on pixelated micropolarizer array.

    PubMed

    Zhang, Zhigang; Dong, Fengliang; Qian, Kemao; Zhang, Qingchuan; Chu, Weiguo; Zhang, Yuntian; Ma, Xuan; Wu, Xiaoping

    2015-08-10

    The special spiral phase structure of an optical vortex leads to an intriguing study in modern singular optics. This paper proposes a real-time phase measurement method of vortex beam based on pixelated micropolarizer array (PMA). Four phase-shifting fringe images can be obtained from a single interference image, thus the vortex beam phase can be obtained in real-time. The proposed method can achieve full-field phase measurement of the vortex beam with the advantages of lower computation and vibration resistance. In the experiments, the typical phases of vortex with different topological charges are loaded on a spatial light modulator (SLM) to generate diffraction vortex beam, and the phase distribution of vortex beam is obtained in real-time, which confirm the robustness of this method. This method is of great significance in promoting the study of optical vortices. PMID:26367904

  10. An automated real-time microscopy system for analysis of fluorescence resonance energy transfer

    NASA Astrophysics Data System (ADS)

    Bernardini, André; Wotzlaw, Christoph; Lipinski, Hans-Gerd; Fandrey, Joachim

    2010-05-01

    Molecular imaging based on Fluorescence Resonance Energy Transfer (FRET) is widely used in cellular physiology both for protein-protein interaction analysis and detecting conformational changes of single proteins, e.g. during activation of signaling cascades. However, getting reliable results from FRET measurements is still hampered by methodological problems such as spectral bleed through, chromatic aberration, focal plane shifts and false positive FRET. Particularly false positive FRET signals caused by random interaction of the fluorescent dyes can easily lead to misinterpretation of the data. This work introduces a Nipkow Disc based FRET microscopy system, that is easy to operate without expert knowledge of FRET. The system automatically accounts for all relevant sources of errors and provides various result presentations of two, three and four dimensional FRET data. Two examples are given to demonstrate the scope of application. An interaction analysis of the two subunits of the hypoxia-inducible transcription factor 1 demonstrates the use of the system as a tool for protein-protein interaction analysis. As an example for time lapse observations, the conformational change of the fluorophore labeled heat shock protein 33 in the presence of oxidant stress is shown.

  11. In-situ real time measurements of net erosion rates of copper during hydrogen plasma exposure

    NASA Astrophysics Data System (ADS)

    Kesler, Leigh; Wright, Graham; Peterson, Ethan; Whyte, Dennis

    2013-10-01

    In order to properly understand the dynamics of net erosion/deposition in fusion reactors, such as tokamaks, a diagnostic measuring the real time rates of net erosion/deposition during plasma exposure is necessary. The DIONISOS experiment produces real time measurements of net erosion/deposition by using Rutherford backscattering spectroscopy (RBS) ion beam analysis simultaneously with plasma exposure from a helicon plasma source. This in-situ method improves on ex-situ weight loss measurements by allowing measurement of possible synergistic effects of high ion implantation rates and net erosion rate and by giving a real time response to changes in plasma parameters. Previous work has validated this new technique for measuring copper (Cu) erosion from helium (He) plasma ion bombardment. This technique is now extended to measure copper erosion due to deuterium and hydrogen plasma ion exposure. Targets used were a 1.5 μm Cu layer on an aluminum substrate. Cu layer thickness is tracked in real time using 1.2 MeV proton RBS. Measured erosion rates will be compared to results from literature and He erosion rates. Supported by US DoE award DE-SC00-02060.

  12. In vitro Real-time Measurement of the Intra-bacterial Redox Potential

    PubMed Central

    van der Heijden, Joris; Finlay, B. Brett

    2016-01-01

    All bacteria that live in oxygenated environments have to deal with oxidative stress caused by some form of exogenous or endogenous reactive oxygen species (ROS) (Imlay, 2013). Large quantities of ROS damage DNA, lipids and proteins which can eventually lead to bacterial cell death (Imlay, 2013). In contrast, smaller quantities of ROS can play more sophisticated roles in cellular signalling pathways affecting almost every process in the bacterial cell e.g. metabolism, stress responses, transcription, protein synthesis, etc. Previously, inadequate analytical methods prevented appropriate analysis of the intra-bacterial redox potential. Herein, we describe a method for the measurement of real-time changes to the intra-bacterial redox potential using redox-sensitive GFP (roGFP2) (van der Heijden et al., 2015). The roGFP2 protein is engineered to contain specific cysteine residues that form an internal disulfide bridge upon oxidation which results in a slight shift in protein conformation (Hanson et al., 2004). This shift results in two distinct protein isoforms with different fluorescence excitation spectra after excitation at 405 nm and 480 nm respectively. Consequently, the corresponding 405/480 nm ratio can be used as a measure for the intra-bacterial redox potential. The ratio-metric analysis excludes variations due to differences in roGFP2 concentrations and since the conformational shift is reversible the system allows for measurement of oxidizing as well as reducing conditions. In this protocol we describe the system by measuring the intra-bacterial redox potential inside Salmonella typhimurium (S. typhimurium) however this system can be adjusted for use in other Gram-negative bacteria.

  13. Rapid kinetic characterization of hammerhead ribozymes by real-time monitoring of fluorescence resonance energy transfer (FRET).

    PubMed Central

    Singh, K K; Parwaresch, R; Krupp, G

    1999-01-01

    In established methods for analyzing ribozyme kinetics, radiolabeled RNA substrates are primarily used. Each data point requires the cumbersome sampling, gel electrophoretic separation, and quantitation of reaction products, apart from the continuous loss of substrate by radioactive decay. We have used stable, double fluorescent end-labeled RNA substrates. Fluorescence of one fluorophore is quenched by intramolecular energy transfer (FRET). Upon substrate cleavage, both dyes become separated in two RNA products and fluorescence is restored. This can be followed in real time and ribozyme reactions can be analyzed under multiple (substrate excess) and under single (ribozyme excess) turnover conditions. A detailed comparison of unlabeled, single, and double fluorescent-labeled RNAs revealed moderate kinetic differences. Results with two systems, hammerhead ribozymes in I/II (small ribozyme, large substrate) and in I/III format (large ribozyme, small substrate), are reported. PMID:10573125

  14. Observation of development of breast cancer cell lines in real time by fluorescence microscopy under simulated microgravity

    NASA Astrophysics Data System (ADS)

    Lavan, David; Valdivia-Silva, Julio E.; Sanabria, Gabriela; Orihuela, Diego; Suarez, Juan; Quispe, Marco; Chuchon, Mariano; Martin, David; Maroto, Marcos; Egea, Javier

    2016-07-01

    This project consist in the implementation of a fluorescence microscope for the in real time monitoring of biological labeled samples by several fluorophores in microgravity conditions keeping the temperature, humidity, and (CO)2 controlled by an electronic platform. The system (fluorescence microscope and incubator) is integrated to a microgravity simulator machine which was presented on the "30th Annual American Society for Gravitation and Space Research Meeting" October 2014 in Pasadena, CA, USA. Currently, we have the microgravity machine biologically validated by genetic expression studies in pupal stage of Drosophila melanogaster. The fluorescence microscope has a platform designed to hold a culture flask, and a fluorescence camera (Leica DFC3000 G) connected to an optical system (Fluorescence Light source Leica EL6000, optic fiber, fiber adapter, and fluorescence filter) in order to take images in real time. The mechanical system of the fluorescence microsc ope is designed to allow the displacement of the fluorescence camera through a parallel plane to the culture flask's plane and also the movement of the platform through a perpendicular axis to the culture flask in order to focus the samples to the optical system. The mechanical system is propelled by four DC moto-reductors with encoder (A-max 26 Maxon motor, GP 32S screw and MR encoder) that generate displacements in the order of micrometers. The angular position control of the DC motoreductor's shaft of all the DC moto-reductors is done by PWM signals based on the interpretation of the signals provided by the encoders during the movement. The system is remotely operated by a graphic interface installed on a personal computer or any mobile device (smartphone, laptop or tablet) by using the internet. Acknowledgments: Grant of INNOVATE PERU (Formerly FINCYT)

  15. Real-Time Fluorescence Tracking of Protoporphyrin Incorporated Thermosensitive Hydrogel and Its Drug Release in Vivo.

    PubMed

    Dong, Xia; Wei, Chang; Liu, Tianjun; Lv, Feng; Qian, Zhiyong

    2016-03-01

    Fluorescence imaging in vivo will pave an important way for the evaluation of biomaterials. The major advantage of fluorescence imaging compared to other imaging modalities is the possibility of tracking two or more fluorescence probes simultaneously with multispectral fluorescence imaging. It is essential to elucidate the location, erosion, drug release and resection of implanted biomaterials in vivo. Herein, a thermosensitive hydrogel with a protoporphyrin core based on a PEG and PCL copolymer (PCL-PEG-PPOR-PEG-PCL) was synthesized by ring-opening polymerization using protoporphyrin as a fluorescence tag. The optical properties of the hydrogel were investigated by UV-vis and fluorescence spectroscopy in vitro and by fluorescence imaging system in vivo. The hydrogel erosion and drug delivery in vivo were monitored and tracked by multispectral fluorescence imaging system in nude mice. The results show that the thermosensitive hydrogel exhibits fluorescence and injectability in vivo with good biocompatibility. Through the modality of fluorescence imaging, the status of the hydrogel is reflected in situ in vivo including its location and erosion. Multispectral analysis separates the autofluorescence signals from the specific label and provides the ability to locate the drug and carrier. The protoporphyrin incorporated thermosensitive hydrogel can be a potential visiable biomedical implant for tissue repair or drug delivery. PMID:26848506

  16. Real-time measurements of a 40 Gb/s coherent system.

    PubMed

    Sun, Han; Wu, Kuang-Tsan; Roberts, Kim

    2008-01-21

    Continuous real-time measurements are shown from a coherent 40 Gb/s transmission system that uses Dual-Polarization Quadrature Phase Shift Keying (DP-QPSK) modulation. Digital compensation is used for dispersion and polarization effects, with little performance degradation created by 150 ps of rapidly varying 1st-order PMD. PMID:18542161

  17. Real-time monitoring of NKCC2 endocytosis by total internal reflection fluorescence (TIRF) microscopy.

    PubMed

    Jaykumar, Ankita Bachhawat; Caceres, Paulo S; Sablaban, Ibrahim; Tannous, Bakhos A; Ortiz, Pablo A

    2016-01-15

    The apical Na-K-2Cl cotransporter (NKCC2) mediates NaCl reabsorption by the thick ascending limb (TAL). The amount of NKCC2 at the apical membrane of TAL cells is determined by exocytic delivery, recycling, and endocytosis. Surface biotinylation allows measurement of NKCC2 endocytosis, but it has low time resolution and does not allow imaging of the dynamic process of endocytosis. We hypothesized that total internal reflection fluorescence (TIRF) microscopy imaging of labeled NKCC2 would allow monitoring of NKCC2 endocytosis in polarized Madin-Darby canine kidney (MDCK) and TAL cells. Thus we generated a NKCC2 construct containing a biotin acceptor domain (BAD) sequence between the transmembrane domains 5 and 6. Once expressed in polarized MDCK or TAL cells, surface NKCC2 was specifically biotinylated by exogenous biotin ligase (BirA). We also demonstrate that expression of a secretory form of BirA in TAL cells induces metabolic biotinylation of NKCC2. Labeling biotinylated surface NKCC2 with fluorescent streptavidin showed that most apical NKCC2 was located within small discrete domains or clusters referred to as "puncta" on the TIRF field. NKCC2 puncta were observed to disappear from the TIRF field, indicating an endocytic event which led to a decrease in the number of surface puncta at a rate of 1.18 ± 0.16%/min in MDCK cells, and a rate 1.09 ± 0.08%/min in TAL cells (n = 5). Treating cells with a cholesterol-chelating agent (methyl-β-cyclodextrin) completely blocked NKCC2 endocytosis. We conclude that TIRF microscopy of labeled NKCC2 allows the dynamic imaging of individual endocytic events at the apical membrane of TAL cells. PMID:26538436

  18. High-throughput platform for real-time monitoring of biological processes by multicolor single-molecule fluorescence

    PubMed Central

    Chen, Jin; Dalal, Ravindra V.; Petrov, Alexey N.; Tsai, Albert; O’Leary, Seán E.; Chapin, Karen; Cheng, Janice; Ewan, Mark; Hsiung, Pei-Lin; Lundquist, Paul; Turner, Stephen W.; Hsu, David R.; Puglisi, Joseph D.

    2014-01-01

    Zero-mode waveguides provide a powerful technology for studying single-molecule real-time dynamics of biological systems at physiological ligand concentrations. We customized a commercial zero-mode waveguide-based DNA sequencer for use as a versatile instrument for single-molecule fluorescence detection and showed that the system provides long fluorophore lifetimes with good signal to noise and low spectral cross-talk. We then used a ribosomal translation assay to show real-time fluidic delivery during data acquisition, showing it is possible to follow the conformation and composition of thousands of single biomolecules simultaneously through four spectral channels. This instrument allows high-throughput multiplexed dynamics of single-molecule biological processes over long timescales. The instrumentation presented here has broad applications to single-molecule studies of biological systems and is easily accessible to the biophysical community. PMID:24379388

  19. DNA detection of Clostridium difficile infection based on real-time resistance measurement.

    PubMed

    Liu, C; Jiang, D N; Xiang, G M; Luo, F K; Liu, L L; Yu, J C; Pu, X Y

    2013-01-01

    We used a newly developed electrochemical method, real-time resistance measurement, based on loop-mediated isothermal amplification (LAMP), with real-time resistance monitoring and derivative analysis. DNA extracted from specimens was amplified through LAMP reaction. The 2 products of LAMP, DNA and pyrophosphate, both are negative ions; they combine with positive dye (crystal violet) and positive ions (Mg(2+)), which leads to an increase in the resistivity of the reaction liquid. The changes of resistivity were measured in real-time with a specially designed resistance electrode, to detect Clostridium difficile DNA. We found that electrochemical detection of C. difficile could be completed in 0.5-1 h, with a detection limit of 10(2) CFU/mL, with high accuracy (95.0%), sensitivity (91.1%), and specificity (97.3%) compared to PCR methods. C. difficile is commonly associated with antibiotic-induced diarrhea. Due to the difficulty in performing anaerobic culture and cytotoxicity neutralization assays, a simple, rapid, sensitive, and accurate method is preferred. We conclude that real-time resistance measurement is a rapid, sensitive, and stable method for the diagnosis of C. difficile infection that could be applied to gene chips and pocket instruments. PMID:24065671

  20. A non-invasive fluorescence-based oxygen sensor and platform for studying cell responses to metabolic agents in real-time

    NASA Astrophysics Data System (ADS)

    Buchapudi, Koutilya Reddy

    A fluorescence-based sensor in a transverse flow/stop measurement platform has been developed to determine real-time changes in oxygen consumption rates for cell metabolic studies. The oxygen sensitive fluorophore platinum octaethylporphyrin was embedded in a cellulose acetate matrix and affixed to a fiber optic bundle, which provided for transmission of the excitation and emission wavelengths of the film. The fiber optic bundle was sealed in a sensor head that can be used in standard 24-well plates common to research labs. The utility of the sensor and sensing platform were determined by measuring the changes in oxygen consumption rates of Candida albicans during 90/30 s flow/stop cycles. Exposure of these cells to metabolic antagonists and an enhancer showed the expected decrease and increase in oxygen consumption rates in real time. The applicability of the platform to biological studies is illustrated by determination of synergistic activities between antifungal drugs and fluoride exposure in Candida albicans. The robustness of the fluorophore film is demonstrated by perfusion with different media and analyte conditions in the absence of cells. For stop cycle time intervals less than 1 minute the sensor exhibited a rapid and fairly linear change in fluorescence intensity to changing oxygen concentrations in the measurement chamber. Flow cycle fluorescence intensities were used as a baseline correction for treating the stop cycle fluorescence peaks.

  1. Real-time remote detection and measurement for airborne imaging spectroscopy: a case study with methane

    NASA Astrophysics Data System (ADS)

    Thompson, D. R.; Leifer, I.; Bovensmann, H.; Eastwood, M.; Fladeland, M.; Frankenberg, C.; Gerilowski, K.; Green, R. O.; Kratwurst, S.; Krings, T.; Luna, B.; Thorpe, A. K.

    2015-10-01

    Localized anthropogenic sources of atmospheric CH4 are highly uncertain and temporally variable. Airborne remote measurement is an effective method to detect and quantify these emissions. In a campaign context, the science yield can be dramatically increased by real-time retrievals that allow operators to coordinate multiple measurements of the most active areas. This can improve science outcomes for both single- and multiple-platform missions. We describe a case study of the NASA/ESA CO2 and MEthane eXperiment (COMEX) campaign in California during June and August/September 2014. COMEX was a multi-platform campaign to measure CH4 plumes released from anthropogenic sources including oil and gas infrastructure. We discuss principles for real-time spectral signature detection and measurement, and report performance on the NASA Next Generation Airborne Visible Infrared Spectrometer (AVIRIS-NG). AVIRIS-NG successfully detected CH4 plumes in real-time at Gb s-1 data rates, characterizing fugitive releases in concert with other in situ and remote instruments. The teams used these real-time CH4 detections to coordinate measurements across multiple platforms, including airborne in situ, airborne non-imaging remote sensing, and ground-based in situ instruments. To our knowledge this is the first reported use of real-time trace-gas signature detection in an airborne science campaign, and presages many future applications. Post-analysis demonstrates matched filter methods providing noise-equivalent (1σ) detection sensitivity for 1.0 % CH4 column enhancements equal to 141 ppm m.

  2. Reversible Fluorescent Nanoswitch Based on Carbon Quantum Dots Nanoassembly for Real-Time Acid Phosphatase Activity Monitoring.

    PubMed

    Qian, Zhaosheng; Chai, Lujing; Zhou, Qian; Huang, Yuanyuan; Tang, Cong; Chen, Jianrong; Feng, Hui

    2015-07-21

    A reversible fluorescence nanoswitch by integrating carbon quantum dots nanoassembly and pyrophosphate ion is developed, and a reliable real-time fluorescent assay for acid phosphatase (ACP) activity is established on the basis of the fluorescence nanoswitch. Carbon quantum dots (CQDs) abundant in carboxyl groups on the surface, nickel(II) ion and pyrophosphate ion comprise the fluorescent nanoswitch, which operates in the following way: the nanoassembly consisting of CQDs and nickel ions can be triggered by pyrophosphate ion serving as an external stimulus. At the same time, the fluorescence nanoswitch switches between two fluorescence states (OFF and ON) accompanying shifts in their physical states aggregation and disaggregation. Based on the nanoswitch, the introduction of ACP leads to breakdown of pyrophosphate ions into phosphate ions and resultant fluorescence quenching due to catalytic hydrolysis of ACP toward pyrophosphate ions (PPi). Quantitative evaluation of ACP activity in a broad range from 18.2 U/L to 1300 U/L, with a detection limit of 5.5 U/L, can be achieved in this way, which endows the assay with sufficiently high sensitivity for practical detection in human serum and seminal plasma. PMID:26115095

  3. Real-time estimation of plasma insulin concentration from continuous glucose monitor measurements.

    PubMed

    de Pereda, Diego; Romero-Vivo, Sergio; Ricarte, Beatriz; Rossetti, Paolo; Ampudia-Blasco, Francisco Javier; Bondia, Jorge

    2016-01-01

    Continuous glucose monitors can measure interstitial glucose concentration in real time for closed-loop glucose control systems, known as artificial pancreas. These control systems use an insulin feedback to maintain plasma glucose concentration within a narrow and safe range, and thus to avoid health complications. As it is not possible to measure plasma insulin concentration in real time, insulin models have been used in literature to estimate them. Nevertheless, the significant inter- and intra-patient variability of insulin absorption jeopardizes the accuracy of these estimations. In order to reduce these limitations, our objective is to perform a real-time estimation of plasma insulin concentration from continuous glucose monitoring (CGM). Hovorka's glucose-insulin model has been incorporated in an extended Kalman filter in which different selected time-variant model parameters have been considered as extended states. The observability of the original Hovorka's model and of several extended models has been evaluated by their Lie derivatives. We have evaluated this methodology with an in-silico study with 100 patients with Type 1 diabetes during 25 h. Furthermore, it has been also validated using clinical data from 12 insulin pump patients with Type 1 diabetes who underwent four mixed meal studies. Real-time insulin estimations have been compared to plasma insulin measurements to assess performance showing the validity of the methodology here used in comparison with that formerly used for insulin models. Hence, real-time estimations for plasma insulin concentration based on subcutaneous glucose monitoring can be beneficial for increasing the efficiency of control algorithms for the artificial pancreas. PMID:26343364

  4. Advanced fluorescence microscopy methods for the real-time study of transcription and chromatin dynamics

    PubMed Central

    Annibale, Paolo; Gratton, Enrico

    2014-01-01

    In this contribution we provide an overview of the recent advances allowed by the use of fluorescence microscopy methods in the study of transcriptional processes and their interplay with the chromatin architecture in living cells. Although the use of fluorophores to label nucleic acids dates back at least to about half a century ago,1 two recent breakthroughs have effectively opened the way to use fluorescence routinely for specific and quantitative probing of chromatin organization and transcriptional activity in living cells: namely, the possibility of labeling first the chromatin loci and then the mRNA synthesized from a gene using fluorescent proteins. In this contribution we focus on methods that can probe rapid dynamic processes by analyzing fast fluorescence fluctuations. PMID:25764219

  5. Real-time emission factor measurements of isocyanic acid from light duty gasoline vehicles

    NASA Astrophysics Data System (ADS)

    Brady, J.; Crisp, T. A.; Collier, S.; Kuwayama, T.; Zhang, Q.; Kleeman, M.; Bertram, T. H.

    2013-12-01

    Recent work has demonstrated the potential for vehicle based anthropogenic sources of the carcinogen isocyanic acid (HNCO) in urban environments. Although emission factors for HNCO have recently been measured for light duty diesel vehicles, light duty gasoline vehicles are not well characterized. Here we will present real-time emission factor measurements of HNCO for light duty gasoline vehicles measured at the California Air Resource Board's Haagen-Smit Laboratory in September of 2011 driven on a chassis dynamometer using the California Unified Driving Cycle. Emission factors for HNCO were determined for eight light duty gasoline vehicles utilizing a fast response chemical ionization time-of-flight mass spectrometer and simultaneous real-time measurements of CO, CO2, and NOx. We will discuss the potential production mechanism for HNCO by light duty gasoline vehicles as well as the potential drive cycle dependency of HNCO production.

  6. A virtual instrument for real time in vivo measurement of carotid artery compliance.

    PubMed

    Joseph, Jayaraj; Jayashankar, V

    2008-01-01

    A new virtual instrument for real time, non invasive measurement of carotid artery compliance is proposed. The instrument is a reliable, compact and low cost alternative to the conventional ultrasound scanner and wall tracking system for carotid artery compliance measurement. The measurement system uses an ultrasound pulse echo method to probe the carotid artery. The reflected echoes are processed using Hilbert transform techniques. Peak detection and echo tracking are implemented in LabVIEW. A comparison is done between manual and automatic method of echo identification. The instrument gives a display of the variation of carotid diameter in real time and calculates the various estimates of arterial compliance from the analyzed data. The capability of the instrument to accurately determine arterial compliance measures is demonstrated by experiments performed on human subjects. PMID:19163155

  7. Digital Holography for in Situ Real-Time Measurement of Plasma-Facing-Component Erosion

    SciTech Connect

    ThomasJr., C. E.; Granstedt, E. M.; Biewer, Theodore M; Baylor, Larry R; Combs, Stephen Kirk; Meitner, Steven J; Hillis, Donald Lee; Majeski, R.; Kaita, R.

    2014-01-01

    In situ, real time measurement of net plasma-facing-component (PFC) erosion/deposition in a real plasma device is challenging due to the need for good spatial and temporal resolution, sufficient sensitivity, and immunity to fringe-jump errors. Design of a high-sensitivity, potentially high-speed, dual-wavelength CO2 laser digital holography system (nominally immune to fringe jumps) for PFC erosion measurement is discussed.

  8. The emergence of flow cytometry for sensitive, real-time measurements of molecular interactions

    SciTech Connect

    Nolan, J.P.; Sklar, L.A. |

    1998-07-01

    The analysis of macromolecular interactions is an essential element of biomedical research. Flow cytometry is uniquely capable of making sensitive and quantitative measurements of molecular interactions. These measurements can be made in real time with subsecond kinetic resolution using purified biomolecules or living cells. Combined with automated sample handling, these features make flow cytometry a versatile and robust technology for the analysis of molecular interactions.

  9. An orange fluorescent protein tagging system for real-time pollen tracking

    PubMed Central

    2013-01-01

    Background Monitoring gene flow could be important for future transgenic crops, such as those producing plant-made-pharmaceuticals (PMPs) in open field production. A Nicotiana hybrid (Nicotiana. tabacum × Nicotiana glauca) shows limited male fertility and could be used as a bioconfined PMP platform. Effective assessment of gene flow from these plants is augmented with methods that utilize fluorescent proteins for transgenic pollen identification. Results We report the generation of a pollen tagging system utilizing an orange fluorescent protein to monitor pollen flow and as a visual assessment of transgene zygosity of the parent plant. This system was created to generate a tagged Nicotiana hybrid that could be used for the incidence of gene flow. Nicotiana tabacum ‘TN 90’ and Nicotiana glauca were successfully transformed via Agrobacterium tumefaciens to express the orange fluorescent protein gene, tdTomato-ER, in pollen and a green fluorescent protein gene, mgfp5-er, was expressed in vegetative structures of the plant. Hybrids were created that utilized the fluorescent proteins as a research tool for monitoring pollen movement and gene flow. Manual greenhouse crosses were used to assess hybrid sexual compatibility with N. tabacum, resulting in seed formation from hybrid pollination in 2% of crosses, which yielded non-viable seed. Pollen transfer to the hybrid formed seed in 19% of crosses and 10 out of 12 viable progeny showed GFP expression. Conclusion The orange fluorescent protein is visible when expressed in the pollen of N. glauca, N. tabacum, and the Nicotiana hybrid, although hybrid pollen did not appear as bright as the parent lines. The hybrid plants, which show limited ability to outcross, could provide bioconfinement with the benefit of detectable pollen using this system. Fluorescent protein-tagging could be a valuable tool for breeding and in vivo ecological monitoring. PMID:24070251

  10. Fluorescent chitosan complex nanosphere diazeniumdiolates as donors and sensitive real-time probes of nitric oxide.

    PubMed

    Tan, Lianjiang; Wan, Ajun; Li, Huili

    2013-02-21

    A new CuFL (2-{2-chloro-6-hydroxy-5-[(2-methyl-quinolin-8-ylamino)-methyl]-3-oxo-3H-xanthen-9-yl}-benzoic acid)-CS (chitosan) NS diazeniumdiolates system consisting of NO donors and highly-sensitive NO probes is reported. FL-CS NS diazeniumdiolates were synthesized by incorporating the fluorescent molecule FL with chitosan (CS) and reacting the resultant FL-CS complex with pressurized NO and dimethyl sulfate (DMS). Then the FL-CS NS diazeniumdiolates were reacted with copper chloride (CuCl(2)) to generate non-fluorescent CuFL-CS NS diazeniumdiolates. The CuFL-CS NS diazeniumdiolates have a spherical outline with a dimension of ca. 250 nm. They have high selectivity for NO over other related substances. The results of in vitro and in vivo experiments indicate that the CuFL-CS NS diazeniumdiolates can release NO under physiological conditions and meanwhile detect the released NO based on the considerable fluorescence increase of the otherwise non-fluorescent system caused by the NO. The good fluorescence stability of the NO-FL-CS NS provides prospects for the CuFL-CS NS diazeniumdiolates in biomedical applications. PMID:23223327

  11. Real-time locating and speed measurement of fibre fuse using optical frequency-domain reflectometry

    NASA Astrophysics Data System (ADS)

    Jiang, Shoulin; Ma, Lin; Fan, Xinyu; Wang, Bin; He, Zuyuan

    2016-05-01

    We propose and experimentally demonstrate real-time locating and speed measurement of fibre fuse by analysing the Doppler shift of reflected light using optical frequency-domain reflectometry (OFDR). Our method can detect the start of a fibre fuse within 200 ms which is equivalent to a propagation distance of about 10 cm in standard single-mode fibre. We successfully measured instantaneous speed of propagating fibre fuses and observed their subtle fluctuation owing to the laser power instability. The resolution achieved for speed measurement in our demonstration is 1 × 10‑3 m/s. We studied the fibre fuse propagation speed dependence on the launched power in different fibres. Our method is promising for both real time fibre fuse monitoring and future studies on its propagation and termination.

  12. Real-time gas density measurement using a ring cavity terahertz parametric oscillator

    NASA Astrophysics Data System (ADS)

    Ohno, S.; Guo, R.; Minamide, H.; Ito, H.

    2007-05-01

    We carried out real-time measurement of gas density using monochromatic terahertz waves. The THz-wave absorbance is useful to measure the density of a gas having a characteristic spectrum in the THz region. We used the ring cavity THz-wave parametric oscillator (ring-TPO) as a monochromatic tunable THz-wave source. One can change the oscillation frequency of ring-TPO with a rotating galvano mirror forming the ring cavity. The frequency can be changed by synchronization with a repeating pump-pulse of 500 Hz. We demonstrated real-time measurement of the gas density in R-22, which had some spectral structure in THz frequency region. The gas density in the sample cell was changed by controlling the pressure to lower than 1 atm. When the gas density in the cell was the most tenuous, the maximum sensitivity was about 5%, which was limited by the fluctuation of THz-wave intensity.

  13. Real-time locating and speed measurement of fibre fuse using optical frequency-domain reflectometry.

    PubMed

    Jiang, Shoulin; Ma, Lin; Fan, Xinyu; Wang, Bin; He, Zuyuan

    2016-01-01

    We propose and experimentally demonstrate real-time locating and speed measurement of fibre fuse by analysing the Doppler shift of reflected light using optical frequency-domain reflectometry (OFDR). Our method can detect the start of a fibre fuse within 200 ms which is equivalent to a propagation distance of about 10 cm in standard single-mode fibre. We successfully measured instantaneous speed of propagating fibre fuses and observed their subtle fluctuation owing to the laser power instability. The resolution achieved for speed measurement in our demonstration is 1 × 10(-3) m/s. We studied the fibre fuse propagation speed dependence on the launched power in different fibres. Our method is promising for both real time fibre fuse monitoring and future studies on its propagation and termination. PMID:27146550

  14. LANL's near-real-time measurement control bolt-on to LANMAS

    SciTech Connect

    Hicks, Ruel D; Boyle, Caroline M

    2010-01-01

    Los Alamos National Laboratory (LANL) has created a near-real-time Measurement Control Program (MCP) that integrates with Local Area Network Material Accounting System (LANMAS). The program was designed to take the place of an aging accounting system at LANL which incorporated the measurement control. LANL's Material Control and Accountability (MC&A) group developed many bolt-on features to enhance LANMAS called LAM CAS (Los Alamos Material Control and Accounting System), one of those bolt-on enhancements was to develop the MCP to replace the previous version. MCP was developed with the multiple end-user groups in mind by creating a near-real-time system that was user friendly, provided access controls, and account status of the measurement control systems.

  15. Real-time locating and speed measurement of fibre fuse using optical frequency-domain reflectometry

    PubMed Central

    Jiang, Shoulin; Ma, Lin; Fan, Xinyu; Wang, Bin; He, Zuyuan

    2016-01-01

    We propose and experimentally demonstrate real-time locating and speed measurement of fibre fuse by analysing the Doppler shift of reflected light using optical frequency-domain reflectometry (OFDR). Our method can detect the start of a fibre fuse within 200 ms which is equivalent to a propagation distance of about 10 cm in standard single-mode fibre. We successfully measured instantaneous speed of propagating fibre fuses and observed their subtle fluctuation owing to the laser power instability. The resolution achieved for speed measurement in our demonstration is 1 × 10−3 m/s. We studied the fibre fuse propagation speed dependence on the launched power in different fibres. Our method is promising for both real time fibre fuse monitoring and future studies on its propagation and termination. PMID:27146550

  16. The detection of T-Nos, a genetic element present in GMOs, by cross-priming isothermal amplification with real-time fluorescence.

    PubMed

    Zhang, Fang; Wang, Liu; Fan, Kai; Wu, Jian; Ying, Yibin

    2014-05-01

    An isothermal cross-priming amplification (CPA) assay for Agrobacterium tumefaciens nopaline synthase terminator (T-Nos) was established and investigated in this work. A set of six specific primers, recognizing eight distinct regions on the T-Nos sequence, was designed. The CPA assay was performed at a constant temperature, 63 °C, and detected by real-time fluorescence. The results indicated that real-time fluorescent CPA had high specificity, and the limit of detection was 1.06 × 10(3) copies of rice genomic DNA, which could be detected in 40 min. Comparison of real-time fluorescent CPA and conventional polymerase chain reaction (PCR) was also performed. Results revealed that real-time fluorescent CPA had a comparable sensitivity to conventional real-time PCR and had taken a shorter time. In addition, different contents of genetically modified (GM)-contaminated rice seed powder samples were detected for practical application. The result showed real-time fluorescent CPA could detect 0.5 % GM-contaminated samples at least, and the whole reaction could be finished in 35 min. Real-time fluorescent CPA is sensitive enough to monitor labeling systems and provides an attractive method for the detection of GMO. PMID:24748469

  17. Augmented microscopy: real-time overlay of bright-field and near-infrared fluorescence images.

    PubMed

    Watson, Jeffrey R; Gainer, Christian F; Martirosyan, Nikolay; Skoch, Jesse; Lemole, G Michael; Anton, Rein; Romanowski, Marek

    2015-10-01

    Intraoperative applications of near-infrared (NIR) fluorescent contrast agents can be aided by instrumentation capable of merging the view of surgical field with that of NIR fluorescence. We demonstrate augmented microscopy, an intraoperative imaging technique in which bright-field (real) and electronically processed NIR fluorescence (synthetic) images are merged within the optical path of a stereomicroscope. Under luminance of 100,000 lx, representing typical illumination of the surgical field, the augmented microscope detects 189 nM concentration of indocyanine green and produces a composite of the real and synthetic images within the eyepiece of the microscope at 20 fps. Augmentation described here can be implemented as an add-on module to visualize NIR contrast agents, laser beams, or various types of electronic data within the surgical microscopes commonly used in neurosurgical, cerebrovascular, otolaryngological, and ophthalmic procedures. PMID:26440760

  18. Augmented microscopy: real-time overlay of bright-field and near-infrared fluorescence images

    NASA Astrophysics Data System (ADS)

    Watson, Jeffrey R.; Gainer, Christian F.; Martirosyan, Nikolay; Skoch, Jesse; Lemole, G. Michael, Jr.; Anton, Rein; Romanowski, Marek

    2015-10-01

    Intraoperative applications of near-infrared (NIR) fluorescent contrast agents can be aided by instrumentation capable of merging the view of surgical field with that of NIR fluorescence. We demonstrate augmented microscopy, an intraoperative imaging technique in which bright-field (real) and electronically processed NIR fluorescence (synthetic) images are merged within the optical path of a stereomicroscope. Under luminance of 100,000 lx, representing typical illumination of the surgical field, the augmented microscope detects 189 nM concentration of indocyanine green and produces a composite of the real and synthetic images within the eyepiece of the microscope at 20 fps. Augmentation described here can be implemented as an add-on module to visualize NIR contrast agents, laser beams, or various types of electronic data within the surgical microscopes commonly used in neurosurgical, cerebrovascular, otolaryngological, and ophthalmic procedures.

  19. Real-time electron density measurements from Cotton-Mouton effect in JET machine

    SciTech Connect

    Brombin, M.; Boboc, A.; Zabeo, L.

    2008-10-15

    Real-time density profile measurements are essential for advanced fusion tokamak operation and interferometry is a proven method for this task. Nevertheless, as a consequence of edge localized modes, pellet injections, fast density increases, or disruptions, the interferometer is subject to fringe jumps, which produce loss of the signal preventing reliable use of the measured density in a real-time feedback controller. An alternative method to measure the density is polarimetry based on the Cotton-Mouton effect, which is proportional to the line-integrated electron density. A new analysis approach has been implemented and tested to verify the reliability of the Cotton-Mouton measurements for a wide range of plasma parameters and to compare the density evaluated from polarimetry with that from interferometry. The density measurements based on polarimetry are going to be integrated in the real-time control system of JET since the difference with the interferometry is within one fringe for more than 90% of the cases.

  20. Real-Time Inhibitor Recession Measurements in the Space Shuttle Reusable Solid Rocket Motors

    NASA Technical Reports Server (NTRS)

    McWhorter, Bruce B.; Ewing, Mark E.; McCool, Alex (Technical Monitor)

    2001-01-01

    Real-time char line recession measurements were made on propellant inhibitors of the Space Shuttle Reusable Solid Rocket Motor (RSRM). The RSRM FSM-8 static test motor propellant inhibitors (composed of a rubber insulation material) were successfully instrumented with eroding potentiometers and thermocouples. The data was used to establish inhibitor recession versus time relationships. Normally, pre-fire and post-fire insulation thickness measurements establish the thermal performance of an ablating insulation material. However, post-fire inhibitor decomposition and recession measurements are complicated by the fact that most of the inhibitor is back during motor operation. It is therefore a difficult task to evaluate the thermal protection offered by the inhibitor material. Real-time measurements would help this task. The instrumentation program for this static test motor marks the first time that real-time inhibitors. This report presents that data for the center and aft field joint forward facing inhibitors. The data was primarily used to measure char line recession of the forward face of the inhibitors which provides inhibitor thickness reduction versus time data. The data was also used to estimate the inhibitor height versus time relationship during motor operation.

  1. 3D real-time measurement system of seam with laser

    NASA Astrophysics Data System (ADS)

    Huang, Min-shuang; Huang, Jun-fen

    2014-02-01

    3-D Real-time Measurement System of seam outline based on Moiré Projection is proposed and designed. The system is composed of LD, grating, CCD, video A/D, FPGA, DSP and an output interface. The principle and hardware makeup of high-speed and real-time image processing circuit based on a Digital Signal Processor (DSP) and a Field Programmable Gate Array (FPGA) are introduced. Noise generation mechanism in poor welding field conditions is analyzed when Moiré stripes are projected on a welding workpiece surface. Median filter is adopted to smooth the acquired original laser image of seam, and then measurement results of a 3-D outline image of weld groove are provided.

  2. Real-time transverse force sensing using fiber Bragg grating through direct Stokes parameters measurement.

    PubMed

    Su, Yang; Zhu, Yong; Zhang, Baofu; Zhou, Hua

    2015-12-14

    Characteristics of a fiber Bragg grating (FBG) transverse force sensor based on Stokes parameters are presented. Real-time force measurement is achieved through direct measurement of the Stokes parameters at single wavelength. A proportional relationship and linear fit are found between Stokes parameters and applied force. The sensitivity and dynamic range dependence on the state of polarization (SOP) of the incident light is investigated theoretically and experimentally. A maximum sensitivity of 0.037/N is experimentally achieved and it can be improved further by adjusting the incident SOP. This design significantly reduces system complexity and improves data processing speed, which has great practical value in real-time FBG sensing applications. PMID:26699020

  3. Rapid assessment of Cascadia tsunamis from real-time PANGA GPS crustal deformation measurements

    NASA Astrophysics Data System (ADS)

    Melbourne, T. I.; Santillan, M.; Miner, A.; Webb, F.

    2008-12-01

    Cascadia's natural hazards include earthquakes, tsunamis, volcanic eruptions, landslides, and tectonic subsidence along its coasts and inland waterways exacerbated by sea-level rise. The Pacific Northwest Geodetic Array, now comprised of nearly 200 continuous GPS receivers, has been deployed over the last two decades to focus exclusively on mitigating these hazards. In addition, over 150 receivers of the EarthScope Plate Boundary Observatory have also been installed in Cascadia, thus comprising a combined network of over 350 instruments. Of the 200 PANGA stations, nearly 140 are high-rate, real-time telemetered receivers mounted on CWU-built, tectonics-grade monuments. These stations straddle active crustal faults, volcanoes and landslides, they span the megathrust forearc and tsunamigenic regions along the Pacific coast, and they monitor ageing man-made structures such as dams, levees and elevated freeways. All data from this array, currently at over 140 stations, is streamed in real-time into CWU where it is archived and processed with JPL's GIPSY software. In 2005 PANGA received support from NASA, NSF and the USGS to implement real-time processing in support of mitigating Cascadia's natural hazards. We have implemented Trimble Navigation's proprietary RTK software and network monitoring software on all 140 stations, and specific parameter estimation routines on a subset of these stations. Pending available funding, we are also working to implement processing of this data with the RTGipsy software, which produces position time series within a global, not local, reference frame. We are currently writing applications that will facilitate rapid recovery during and after a large seismic event, tsunami, or volcanic eruption. These applications are focused on: - Inverting GPS deformation measurements for earthquake fault location, size, and slip distribution; - Using slip distributions to predict tsunami magnitude and run-up estimates; - Real-time monitoring of

  4. Analytical real-time measurement of a three-dimensional weld pool surface

    NASA Astrophysics Data System (ADS)

    Zhang, WeiJie; Wang, XueWu; Zhang, YuMing

    2013-11-01

    The ability to observe and measure weld pool surfaces in real-time is the core of the foundation for next generation intelligent welding that can partially imitate skilled welders who observe the weld pool to acquire information on the welding process. This study aims at the real-time measurement of the specular three-dimensional (3D) weld pool surface under a strong arc in gas tungsten arc welding (GTAW). An innovative vision system is utilized in this study to project a dot-matrix laser pattern on the specular weld pool surface. Its reflection from the surface is intercepted at a distance from the arc by a diffuse plane. The intercepted laser dots illuminate this plane producing an image showing the reflection pattern. The deformation of this reflection pattern from the projected pattern (e.g. the dot matrix) is used to derive the 3D shape of the reflection surface, i.e., the weld pool surface. Based on careful analysis, the underlying reconstruction problem is formulated mathematically. An analytic solution is proposed to solve this formulated problem resulting in the weld pool surface being reconstructed on average in 3.04 ms during welding experiments. A vision-based monitoring system is thus established to measure the weld pool surface in GTAW in real-time. In order to verify the effectiveness of the proposed reconstruction algorithm, first numerical simulation is conducted. The proposed algorithm is then tested on a spherical convex mirror with a priori knowledge of its geometry. The detailed analysis of the measurement error validates the accuracy of the proposed algorithm. Results from the real-time experiments verify the robustness of the proposed reconstruction algorithm.

  5. Real-time thermal imaging of microwave accelerated metal-enhanced fluorescence (MAMEF) based assays on sapphire plates.

    PubMed

    Previte, Michael J R; Zhang, Yongxia; Aslan, Kadir; Geddes, Chris D

    2007-11-01

    In this paper, we describe an optical geometry that facilitates our further characterization of the temperature changes above silver island films (SiFs) on sapphire plates, when exposed to microwave radiation. Since sapphire transmits IR, we designed an optical scheme to capture real-time temperature images of a thin water film on sapphire plates with and without SiFs during the application of a short microwave pulse. Using this optical scheme, we can accurately determine the temperature profile of solvents in proximity to metal structures when exposed to microwave irradiation. We believe that this optical scheme will provide us with a basis for further studies in designing metal structures to further improve plasmonic-fluorescence clinical sensing applications, such as those used in microwave accelerated metal-enhanced fluorescence (MAMEF). PMID:17902038

  6. Real-Time Characterization of Virulence Factor Expression in Yersinia pestis Using a Green Fluorescent Protein Reporter System

    SciTech Connect

    Forde, C; Rocco, J; Fitch, J P; McCutchen-Maloney, S

    2004-06-09

    A real-time reporter system was developed to monitor the thermal induction of virulence factors in Yersinia pestis. The reporter system consists of a plasmid in Y. pestis in which the expression of green fluorescent protein (GFP) is under the control of the promoters for six virulence factors, yopE, sycE, yopK, yopT, yscN, and lcrE/yopN, which are all components of the Type III secretion virulence mechanism of Y. pestis. Induction of the expression of these genes in vivo was determined by the increase in fluorescence intensity of GFP in real time. Basal expression levels observed for the Y. pestis promoters, expressed as percentages of the positive control with GFP under the control of the lac promoter, were: yopE (15%), sycE (15%), yopK (13%), yopT (4%), lcrE (3.3%) and yscN (0.8%). The yopE reporter showed the strongest gene induction following temperature transition from 26 C to 37 C. The induction levels of the other virulence factors, expressed as percentages of yopE induction, were: yopK (57%), sycE (9%), yscN (3%), lcrE (3%), and yopT (2%). The thermal induction of each of these promoter fusions was repressed by calcium, and the ratios of the initial rates of thermal induction without calcium supplementation compared to the rate with calcium supplementation were: yopE (11 fold), yscN (7 fold), yopK (6 fold), lcrE (3 fold), yopT (2 fold), and sycE (2 fold). This work demonstrates a novel approach to quantify gene induction and provides a method to rapidly determine the effects of external stimuli on expression of Y. pestis virulence factors in real time, in living cells.

  7. Fluorescent microscope system to monitor real-time interactions between focused ultrasound, echogenic drug delivery vehicles, and live cell membranes.

    PubMed

    Ibsen, Stuart; Benchimol, Michael; Esener, Sadik

    2013-01-01

    Rapid development in the field of ultrasound triggered drug delivery has made it essential to study the real-time interaction between the membranes of live cells and the membranes of echogenic delivery vehicles under exposure to focused ultrasound. The objective of this work was to design an analysis system that combined fluorescent imagining, high speed videography, and definable pulse sequences of focused ultrasound to allow for real time observations of both cell and vehicle membranes. Documenting the behavior of the membranes themselves has not previously been possible due to limitations with existing optical systems used to understand the basic physics of microbubble/ultrasound interaction and the basic interaction between microbubbles and cells. The performance of this new system to monitor membrane behavior was demonstrated by documenting the modes of vehicle fragmentation at different ultrasound intensity levels. At 1.5MPa the membranes were shown to completely fragment while at intensities below 1MPa the membranes pop open and slowly unfold. The interaction between these vehicles and cell membranes was also documented by the removal of fluorescent particles from the surfaces of live cells out to 20μm from the microbubble location. The fluid flow created by microstreaming around ensonated microbubbles was documented at video recording speeds from 60 to 18,000 frames per second. This information about membrane behavior allows the chemical and physical properties of the drug delivery vehicle to be designed along with the ultrasound pulse sequence to cause the most efficient drug delivery. PMID:22749476

  8. Real-time full bandwidth measurement of spectral noise in supercontinuum generation

    PubMed Central

    Wetzel, B.; Stefani, A.; Larger, L.; Lacourt, P. A.; Merolla, J. M.; Sylvestre, T.; Kudlinski, A.; Mussot, A.; Genty, G.; Dias, F.; Dudley, J. M.

    2012-01-01

    The ability to measure real-time fluctuations of ultrashort pulses propagating in optical fiber has provided significant insights into fundamental dynamical effects such as modulation instability and the formation of frequency-shifting rogue wave solitons. We report here a detailed study of real-time fluctuations across the full bandwidth of a fiber supercontinuum which directly reveals the significant variation in measured noise statistics across the spectrum, and which allows us to study correlations between widely separated spectral components. For two different propagation distances corresponding to the onset phase of spectral broadening and the fully-developed supercontinuum, we measure real time noise across the supercontinuum bandwidth, and we quantify the supercontinuum noise using statistical higher-order moments and a frequency-dependent intensity correlation map. We identify correlated spectral regions within the supercontinuum associated with simultaneous sideband generation, as well as signatures of pump depletion and soliton-like pump dynamics. Experimental results are in excellent agreement with simulations. PMID:23193436

  9. Real-time measurement of dust in the workplace using video exposure monitoring: Farming to pharmaceuticals

    NASA Astrophysics Data System (ADS)

    Walsh, P. T.; Forth, A. R.; Clark, R. D. R.; Dowker, K. P.; Thorpe, A.

    2009-02-01

    Real-time, photometric, portable dust monitors have been employed for video exposure monitoring (VEM) to measure and highlight dust levels generated by work activities, illustrate dust control techniques, and demonstrate good practice. Two workplaces, presenting different challenges for measurement, were used to illustrate the capabilities of VEM: (a) poultry farming activities and (b) powder transfer operations in a pharmaceutical company. For the poultry farm work, the real-time monitors were calibrated with respect to the respirable and inhalable dust concentrations using cyclone and IOM reference samplers respectively. Different rankings of exposure for typical activities were found on the small farm studied here compared to previous exposure measurements at larger poultry farms: these were mainly attributed to the different scales of operation. Large variations in the ratios of respirable, inhalable and real-time monitor TWA concentrations of poultry farm dust for various activities were found. This has implications for the calibration of light-scattering dust monitors with respect to inhalable dust concentration. In the pharmaceutical application, the effectiveness of a curtain barrier for dust control when dispensing powder in a downflow booth was rapidly demonstrated.

  10. The potential applications of real-time monitoring of water quality in a large shallow lake (Lake Taihu, China) using a chromophoric dissolved organic matter fluorescence sensor.

    PubMed

    Niu, Cheng; Zhang, Yunlin; Zhou, Yongqiang; Shi, Kun; Liu, Xiaohan; Qin, Boqiang

    2014-01-01

    This study presents results from field surveys performed over various seasons in a large, eutrophic, shallow lake (Lake Taihu, China) using an in situ chromophoric dissolved organic matter (CDOM) fluorescence sensor as a surrogate for other water quality parameters. These measurements identified highly significant empirical relationships between CDOM concentration measured using the in situ fluorescence sensor and CDOM absorption, fluorescence, dissolved organic carbon (DOC), chemical oxygen demand (COD) and total phosphorus (TP) concentrations. CDOM concentration expressed in quinine sulfate equivalent units, was highly correlated with the CDOM absorption coefficient (r(2) = 0.80, p < 0.001), fluorescence intensities (Ex./Em. 370/460 nm) (r(2) = 0.91, p < 0.001), the fluorescence index (r(2) = 0.88, p < 0.001) and the humification index (r(2) = 0.78, p < 0.001), suggesting that CDOM concentration measured using the in situ fluorescence sensor could act as a substitute for the CDOM absorption coefficient and fluorescence measured in the laboratory. Similarly, CDOM concentration was highly correlated with DOC concentration (r(2) = 0.68, p < 0.001), indicating that in situ CDOM fluorescence sensor measurements could be a proxy for DOC concentration. In addition, significant positive correlations were found between laboratory CDOM absorption coefficients and COD (r(2) = 0.83, p < 0.001), TP (r(2) = 0.82, p < 0.001) concentrations, suggesting a potential further application for the real-time monitoring of water quality using an in situ CDOM fluorescence sensor. PMID:24984060

  11. The Potential Applications of Real-Time Monitoring of Water Quality in a Large Shallow Lake (Lake Taihu, China) Using a Chromophoric Dissolved Organic Matter Fluorescence Sensor

    PubMed Central

    Niu, Cheng; Zhang, Yunlin; Zhou, Yongqiang; Shi, Kun; Liu, Xiaohan; Qin, Boqiang

    2014-01-01

    This study presents results from field surveys performed over various seasons in a large, eutrophic, shallow lake (Lake Taihu, China) using an in situ chromophoric dissolved organic matter (CDOM) fluorescence sensor as a surrogate for other water quality parameters. These measurements identified highly significant empirical relationships between CDOM concentration measured using the in situ fluorescence sensor and CDOM absorption, fluorescence, dissolved organic carbon (DOC), chemical oxygen demand (COD) and total phosphorus (TP) concentrations. CDOM concentration expressed in quinine sulfate equivalent units, was highly correlated with the CDOM absorption coefficient (r2 = 0.80, p < 0.001), fluorescence intensities (Ex./Em. 370/460 nm) (r2 = 0.91, p < 0.001), the fluorescence index (r2 = 0.88, p < 0.001) and the humification index (r2 = 0.78, p < 0.001), suggesting that CDOM concentration measured using the in situ fluorescence sensor could act as a substitute for the CDOM absorption coefficient and fluorescence measured in the laboratory. Similarly, CDOM concentration was highly correlated with DOC concentration (r2 = 0.68, p < 0.001), indicating that in situ CDOM fluorescence sensor measurements could be a proxy for DOC concentration. In addition, significant positive correlations were found between laboratory CDOM absorption coefficients and COD (r2 = 0.83, p < 0.001), TP (r2 = 0.82, p < 0.001) concentrations, suggesting a potential further application for the real-time monitoring of water quality using an in situ CDOM fluorescence sensor. PMID:24984060

  12. Real time kinetics of restriction endonuclease cleavage monitored by fluorescence resonance energy transfer.

    PubMed Central

    Ghosh, S S; Eis, P S; Blumeyer, K; Fearon, K; Millar, D P

    1994-01-01

    The kinetics of PaeR7 endonuclease-catalysed cleavage reactions of fluorophor-labeled oligonucleotide substrates have been examined using fluorescence resonance energy transfer (FRET). A series of duplex substrates were synthesized with an internal CTCGAG PaeR7 recognition site and donor (fluorescein) and acceptor (rhodamine) dyes conjugated to the opposing 5' termini. The time-dependent increase in donor fluorescence resulting from restriction cleavage of these substrates was continuously monitored and the initial rate data was fitted to the Michaelis-Menten equation. The steady state kinetic parameters for these substrates were in agreement with the rate constants obtained from a gel electrophoresis-based fixed time point assay using radiolabeled substrates. The FRET method provides a rapid continuous assay as well as high sensitivity and reproducibility. These features should make the technique useful for the study of DNA-cleaving enzymes. Images PMID:8065930

  13. Real-Time Aerodynamic Parameter Estimation without Air Flow Angle Measurements

    NASA Technical Reports Server (NTRS)

    Morelli, Eugene A.

    2010-01-01

    A technique for estimating aerodynamic parameters in real time from flight data without air flow angle measurements is described and demonstrated. The method is applied to simulated F-16 data, and to flight data from a subscale jet transport aircraft. Modeling results obtained with the new approach using flight data without air flow angle measurements were compared to modeling results computed conventionally using flight data that included air flow angle measurements. Comparisons demonstrated that the new technique can provide accurate aerodynamic modeling results without air flow angle measurements, which are often difficult and expensive to obtain. Implications for efficient flight testing and flight safety are discussed.

  14. Development of a capacitive ice sensor to measure ice growth in real time.

    PubMed

    Zhi, Xiang; Cho, Hyo Chang; Wang, Bo; Ahn, Cheol Hee; Moon, Hyeong Soon; Go, Jeung Sang

    2015-01-01

    This paper presents the development of the capacitive sensor to measure the growth of ice on a fuel pipe surface in real time. The ice sensor consists of pairs of electrodes to detect the change in capacitance and a thermocouple temperature sensor to examine the ice formation situation. In addition, an environmental chamber was specially designed to control the humidity and temperature to simulate the ice formation conditions. From the humidity, a water film is formed on the ice sensor, which results in an increase in capacitance. Ice nucleation occurs, followed by the rapid formation of frost ice that decreases the capacitance suddenly. The capacitance is saturated. The developed ice sensor explains the ice growth providing information about the icing temperature in real time. PMID:25808770

  15. Development of a Capacitive Ice Sensor to Measure Ice Growth in Real Time

    PubMed Central

    Zhi, Xiang; Cho, Hyo Chang; Wang, Bo; Ahn, Cheol Hee; Moon, Hyeong Soon; Go, Jeung Sang

    2015-01-01

    This paper presents the development of the capacitive sensor to measure the growth of ice on a fuel pipe surface in real time. The ice sensor consists of pairs of electrodes to detect the change in capacitance and a thermocouple temperature sensor to examine the ice formation situation. In addition, an environmental chamber was specially designed to control the humidity and temperature to simulate the ice formation conditions. From the humidity, a water film is formed on the ice sensor, which results in an increase in capacitance. Ice nucleation occurs, followed by the rapid formation of frost ice that decreases the capacitance suddenly. The capacitance is saturated. The developed ice sensor explains the ice growth providing information about the icing temperature in real time. PMID:25808770

  16. Real-time data acquisition and control system for the measurement of motor and neural data.

    PubMed

    Bryant, Christopher L; Gandhi, Neeraj J

    2005-03-30

    This paper outlines a powerful, yet flexible real-time data acquisition and control system for use in the triggering and measurement of both analog and digital events. Built using the LabVIEW development architecture (version 7.1) and freely available, this system provides precisely timed auditory and visual stimuli to a subject while recording analog data and timestamps of neural activity retrieved from a window discriminator. The system utilizes the most recent real-time (RT) technology in order to provide not only a guaranteed data acquisition rate of 1 kHz, but a much more difficult to achieve guaranteed system response time of 1 ms. The system interface is windows-based and easy to use, providing a host of configurable options for end-user customization. PMID:15698659

  17. Real-Time Unsteady Loads Measurements Using Hot-Film Sensors

    NASA Technical Reports Server (NTRS)

    Mangalam, Arun S.; Moes, Timothy R.

    2004-01-01

    Several flight-critical aerodynamic problems such as buffet, flutter, stall, and wing rock are strongly affected or caused by abrupt changes in unsteady aerodynamic loads and moments. Advanced sensing and flow diagnostic techniques have made possible simultaneous identification and tracking, in real-time, of the critical surface, viscosity-related aerodynamic phenomena under both steady and unsteady flight conditions. The wind tunnel study reported here correlates surface hot-film measurements of leading edge stagnation point and separation point, with unsteady aerodynamic loads on a NACA 0015 airfoil. Lift predicted from the correlation model matches lift obtained from pressure sensors for an airfoil undergoing harmonic pitchup and pitchdown motions. An analytical model was developed that demonstrates expected stall trends for pitchup and pitchdown motions. This report demonstrates an ability to obtain unsteady aerodynamic loads in real-time, which could lead to advances in air vehicle safety, performance, ride-quality, control, and health management.

  18. Dynamical theory of spin noise and relaxation: Prospects for real-time NMR measurements.

    PubMed

    Field, Timothy R

    2014-11-01

    Recent developments in theoretical aspects of spin noise and relaxation and their interrelationship reveal a modified spin density, distinct from the density matrix, as the necessary object to describe fluctuations in spin systems. These fluctuations are to be viewed as an intrinsic quantum mechanical property of such systems immersed in random magnetic environments and are observed as "spin noise" in the absence of any radio frequency excitation. With the prospect of ultrafast digitization, the role of spin noise in real-time parameter extraction for (NMR) spin systems, and the advantage over standard techniques, is of essential importance, especially for systems containing a small number of spins. In this article we outline prospects for harnessing the recent dynamical theory in terms of spin-noise measurement, with attention to real-time properties. PMID:25493776

  19. Real-time digital heterodyne interferometer for high resolution plasma density measurements at ISTTOK

    SciTech Connect

    Marques, T. G.; Gouveia, A.; Pereira, T.; Fortunato, J.; Carvalho, B. B.; Sousa, J.; Silva, C.; Fernandes, H.

    2008-10-15

    With the implementation of alternating discharges (ac) at the ISTTOK tokamak, the typical duration of the discharges increased from 35 to 250 ms. This time increase created the need for a real-time electron density measurement in order to control the plasma fueling. The diagnostic chosen for the real-time calculation was the microwave interferometer. The ISTTOK microwave interferometer is a heterodyne system with quadrature detection and a probing frequency of 100 GHz ({lambda}{sub 0}=3 mm). In this paper, a low-cost approach for real-time diagnostic using a digital signal programable intelligent computer embedded system is presented, which allows the measurement of the phase with a 1% fringe accuracy in less than 6 {mu}s. The system increases its accuracy by digitally correcting the offsets of the input signals and making use of a judicious lookup table optimized to improve the nonlinear behavior of the transfer curve. The electron density is determined at a rate of 82 kHz (limited by the analog to digital converter), and the data are transmitted for each millisecond although this last parameter could be much lower (around 12 {mu}s--each value calculated is transmitted). In the future, this same system is expected to control plasma actuators, such as the piezoelectric valve of the hydrogen injection system responsible for the plasma fueling.

  20. Real-time measurements of local myocardium motion and arterial wall thickening.

    PubMed

    Kanai, H; Koiwa, Y; Zhang, J

    1999-01-01

    We have already developed a new method, namely, the phased tracking method, to track the movement of the heart wall and arterial wall accurately based on both the phase and magnitude of the demodulated signals to determine the instantaneous position of an object. This method has been realized by an off-line measurement system, which cannot be applied to transient evaluation of rapid response of the cardiovascular system to physiological stress. In this paper, therefore, a real-time system to measure change in the thickness of the myocardium and the arterial wall is presented. In this system, an analytic signal from standard ultrasonic diagnostic equipment is analogue-to-digital (A/D) converted at a sampling frequency of 1 MHz. By pipelining and parallel processing using four high-speed digital signal processing (DSP) chips, the method described is realized in real time. The tracking results for both sides of the heart and/or arterial wall are superimposed on the M (motion)-mode image in the work station (WS), and the thickness changes of the heart and/or arterial wall are also displayed and digital-to-analogue (D/A) converted in real time. From the regional change in thickness of the heart wall, spatial distribution of myocardial motility and contractility can be evaluated. For the arterial wall, its local elasticity can be evaluated by referring to the blood pressure. In in vivo experiments, the rapid response of the change in wall thickness of the carotid artery to the dose of the nitroglycerine (NTG) is evaluated. This new real-time system offers potential for quantitative diagnosis of myocardial motility, early stage atherosclerosis, and the transient evaluation of the rapid response of the cardiovascular system to physiological stress. PMID:18244316

  1. Measurement of bow tie profiles in CT scanners using a real-time dosimeter

    SciTech Connect

    Whiting, Bruce R.; Evans, Joshua D.; Williamson, Jeffrey F.; Dohatcu, Andreea C.; Politte, David G.

    2014-10-15

    Purpose: Several areas of computed tomography (CT) research require knowledge about the intensity profile of the x-ray fan beam that is introduced by a bow tie filter. This information is considered proprietary by CT manufacturers, so noninvasive measurement methods are required. One method using real-time dosimeters has been proposed in the literature. A commercially available dosimeter was used to apply that method, and analysis techniques were developed to extract fan beam profiles from measurements. Methods: A real-time ion chamber was placed near the periphery of an empty CT gantry and the dose rate versus time waveform was recorded as the x-ray source rotated about the isocenter. In contrast to previously proposed analysis methods that assumed a pointlike detector, the finite-size ion chamber received varying amounts of coverage by the collimated x-ray beam during rotation, precluding a simple relationship between the source intensity as a function of fan beam angle and measured intensity. A two-parameter model for measurement intensity was developed that included both effective collimation width and source-to-detector distance, which then was iteratively solved to minimize the error between duplicate measurements at corresponding fan beam angles, allowing determination of the fan beam profile from measured dose-rate waveforms. Measurements were performed on five different scanner systems while varying parameters such as collimation, kVp, and bow tie filters. On one system, direct measurements of the bow tie profile were collected for comparison with the real-time dosimeter technique. Results: The data analysis method for a finite-size detector was found to produce a fan beam profile estimate with a relative error between duplicate measurement intensities of <5%. It was robust over a wide range of collimation widths (e.g., 1–40 mm), producing fan beam profiles that agreed with a relative error of 1%–5%. Comparison with a direct measurement technique on

  2. Modular instrumentation system for real-time measurements and control on reciprocating engines

    NASA Technical Reports Server (NTRS)

    Rice, W. J.; Birchenough, A. G.

    1980-01-01

    An instrumentation system was developed for reciprocating engines. Among the parameters measured are the indicated mean effective pressure, or theoretical work per cycle, and the mass fraction burn rate, a measure of the combustion rate in the cylinder. These computations are performed from measured cylinder pressure and crankshaft angle and are available in real time for the experimenter. A 100 or 200 consecutive-cycle sample is analyzed to reduce the effect of cyclic variations in the engine. Data are displayed in bargraph form, and the mean and standard deviation are computed. Other instruments are also described.

  3. Real-time analysis of epithelial-mesenchymal transition using fluorescent single-domain antibodies

    PubMed Central

    Maier, Julia; Traenkle, Bjoern; Rothbauer, Ulrich

    2015-01-01

    Vimentin has become an important biomarker for epithelial-mesenchymal transition (EMT), a highly dynamic cellular process involved in the initiation of metastasis and cancer progression. To date there is no approach available to study endogenous vimentin in a physiological context. Here, we describe the selection and targeted modification of novel single-domain antibodies, so-called nanobodies, to trace vimentin in various cellular assays. Most importantly, we generated vimentin chromobodies by combining the binding moieties of the nanobodies with fluorescent proteins. Following chromobody fluorescence in a cancer-relevant cellular model, we were able for the first time to monitor and quantify dynamic changes of endogenous vimentin upon siRNA-mediated knockdown, induction with TGF-β and modification with Withaferin A by high-content imaging. This versatile approach allows detailed studies of the spatiotemporal organization of vimentin in living cells. It enables the identification of vimentin-modulating compounds, thereby providing the basis to screen for novel therapeutics affecting EMT. PMID:26292717

  4. Fluorescently labeled adrenomedullin allows real-time monitoring of adrenomedullin receptor trafficking in living cells.

    PubMed

    Schönauer, Ria; Kaiser, Anette; Holze, Cathleen; Babilon, Stefanie; Köbberling, Johannes; Riedl, Bernd; Beck-Sickinger, Annette G

    2015-12-01

    The human adrenomedullin (ADM) is a 52 amino acid peptide hormone belonging to the calcitonin family of peptides, which plays a major role in the development and regulation of cardiovascular and lymphatic systems. For potential use in clinical applications, we aimed to investigate the fate of the peptide ligand after binding and activation of the adrenomedullin receptor (AM1), a heterodimer consisting of the calcitonin receptor-like receptor (CLR), a G protein-coupled receptor, associated with the receptor activity-modifying protein 2 (RAMP2). Full length and N-terminally shortened ADM peptides were synthesized using Fmoc/tBu solid phase peptide synthesis and site-specifically labeled with the fluorophore carboxytetramethylrhodamine (Tam) either by amide bond formation or copper(I)-catalyzed azide alkyne cycloaddition. For the first time, Tam-labeled ligands allowed the observation of co-internalization of the whole ligand-receptor complex in living cells co-transfected with fluorescent fusion proteins of CLR and RAMP2. Application of a fluorescent probe to track lysosomal compartments revealed that ADM together with the CLR/RAMP2-complex is routed to the degradative pathway. Moreover, we found that the N-terminus of ADM is not a crucial component of the peptide sequence in terms of AM1 internalization behavior. PMID:26767744

  5. Fluorescence spectroscopy approaches for the development of a real-time organophosphate detection system using an enzymatic sensor.

    PubMed

    Carullo, Paola; Cetrangolo, Giovanni Paolo; Mandrich, Luigi; Manco, Giuseppe; Febbraio, Ferdinando

    2015-01-01

    Organophosphates are organic substances that contain a phosphoryl or a thiophosphoryl bond. They are mainly used around the world as pesticides, but can also be used as chemical warfare agents. Their detection is normally entrusted to techniques like GC- and LC-MS that, although sensitive, do not allow their identification on site and in real time. We have approached their identification by exploiting the high-affinity binding of these compounds with the esterase 2 from Alicyclobacillus acidocaldarius. Using an in silico analysis to evaluate the binding affinities of the enzyme with organophosphate inhibitors, like paraoxon, and other organophosphate compounds, like parathion, chlorpyriphos, and other organophosphate thio-derivatives, we have designed fluorescence spectroscopy experiments to study the quenching of the tryptophan residues after esterase 2 binding with the organophosphate pesticides. The changes in the fluorescence signals permitted an immediate and quantitative identification of these compounds from nano- to picomolar concentrations. A fluorescence based polarity-sensitive probe (ANS) was also employed as a means to understand the extent of the interactions involved, as well as to explore other ways to detect organophosphate pesticides. Finally, we designed a framework for the development of a biosensor that exploits fluorescence technology in combination with a sensitive and very stable bio-receptor. PMID:25671511

  6. Fluorescence Spectroscopy Approaches for the Development of a Real-Time Organophosphate Detection System Using an Enzymatic Sensor

    PubMed Central

    Carullo, Paola; Cetrangolo, Giovanni Paolo; Mandrich, Luigi; Manco, Giuseppe; Febbraio, Ferdinando

    2015-01-01

    Organophosphates are organic substances that contain a phosphoryl or a thiophosphoryl bond. They are mainly used around the world as pesticides, but can also be used as chemical warfare agents. Their detection is normally entrusted to techniques like GC- and LC-MS that, although sensitive, do not allow their identification on site and in real time. We have approached their identification by exploiting the high-affinity binding of these compounds with the esterase 2 from Alicyclobacillus acidocaldarius. Using an in silico analysis to evaluate the binding affinities of the enzyme with organophosphate inhibitors, like paraoxon, and other organophosphate compounds, like parathion, chlorpyriphos, and other organophosphate thio-derivatives, we have designed fluorescence spectroscopy experiments to study the quenching of the tryptophan residues after esterase 2 binding with the organophosphate pesticides. The changes in the fluorescence signals permitted an immediate and quantitative identification of these compounds from nano- to picomolar concentrations. A fluorescence based polarity-sensitive probe (ANS) was also employed as a means to understand the extent of the interactions involved, as well as to explore other ways to detect organophosphate pesticides. Finally, we designed a framework for the development of a biosensor that exploits fluorescence technology in combination with a sensitive and very stable bio-receptor. PMID:25671511

  7. Recent advances in real-time analysis of ionograms and ionospheric drift measurements with digisondes

    NASA Astrophysics Data System (ADS)

    Reinisch, B. W.; Huang, X.; Galkin, I. A.; Paznukhov, V.; Kozlov, A.

    2005-08-01

    Reliable long distance RF communication and transionospheric radio links depend critically on space weather, and specifically ionospheric conditions. Modern ground-based ionosondes provide space weather parameters in real-time including the vertical electron density distribution up to ˜1000 km and the velocity components of the ionospheric F region drift. A global network of digisondes distributes this information in real-time via internet connections. The quality of the automatic scaling of the echo traces in ionograms was a continuous concern ever since first attempts have been reported. The modern low-power ionosonde with ˜100 W transmitters (compared to several kilowatt for the older ionosondes) relies on more sophisticated signal processing to enhance the signal-to-noise ratio and to retrieve the essential ionospheric characteristics. Recent advances in the automatic scaling algorithm ARTIST have significantly increased the reliability of the autoscaled data, making the data, in combination with models, more useful for ionospheric now-casting. Vertical and horizontal F region drift velocities are a new real-time output of the digisondes. The “ionosonde drift” is derived from the measured Doppler frequency shift and angle of arrival of ionospherically reflected HF echoes, a method similar to that used by coherent VHF and incoherent scatter radars.

  8. Real-time high-resolution measurement of collagen alignment in dynamically loaded soft tissue

    NASA Astrophysics Data System (ADS)

    York, Timothy; Kahan, Lindsey; Lake, Spencer P.; Gruev, Viktor

    2014-06-01

    A technique for creating maps of the direction and strength of fiber alignment in collagenous soft tissues is presented. The method uses a division of focal plane polarimeter to measure circularly polarized light transmitted through the tissue. The architecture of the sensor allows measurement of the retardance and fiber alignment at the full frame rate of the sensor without any moving optics. The technique compares favorably to the standard method of using a rotating polarizer. How the new technique enables real-time capture of the full angular spread of fiber alignment and retardance under various cyclic loading conditions is illustrated.

  9. Environmental Measurement-While-Drilling System for Real-Time Field Screening of Contaminants

    SciTech Connect

    Bishop, L.B.; Lockwood, G.J.; Normann, R.A.; Selph, M.M.; Williams, C.V.

    1999-02-22

    Sampling during environmental drilling is essential to fully characterize the spatial distribution and migration of near surface contaminants. However, analysis of the samples is expensive and time-consuming: off-site laboratory analysis can take weeks or months. An alternative screening technology, Environmental Measurement-While-Drilling (EMWD), could save money and valuable time by quickly distinguishing between contaminated and uncontaminated areas. Real time measurements provided by an EMWD system enable on-the-spot decisions to be made regarding sampling strategies. The system also enhances worker safety and provides the added flexibility of being able to steer a drill bit in or out of hazardous zones.

  10. Laser 3-D measuring system and real-time visual feedback for teaching and correcting breathing

    NASA Astrophysics Data System (ADS)

    Povšič, Klemen; Fležar, Matjaž; Možina, Janez; Jezeršek, Matija

    2012-03-01

    We present a novel method for real-time 3-D body-shape measurement during breathing based on the laser multiple-line triangulation principle. The laser projector illuminates the measured surface with a pattern of 33 equally inclined light planes. Simultaneously, the camera records the distorted light pattern from a different viewpoint. The acquired images are transferred to a personal computer, where the 3-D surface reconstruction, shape analysis, and display are performed in real time. The measured surface displacements are displayed with a color palette, which enables visual feedback to the patient while breathing is being taught. The measuring range is approximately 400×600×500 mm in width, height, and depth, respectively, and the accuracy of the calibrated apparatus is +/-0.7 mm. The system was evaluated by means of its capability to distinguish between different breathing patterns. The accuracy of the measured volumes of chest-wall deformation during breathing was verified using standard methods of volume measurements. The results show that the presented 3-D measuring system with visual feedback has great potential as a diagnostic and training assistance tool when monitoring and evaluating the breathing pattern, because it offers a simple and effective method of graphical communication with the patient.

  11. Real time pressure-volume loops in mice using complex admittance: measurement and implications.

    PubMed

    Kottam, Anil T G; Porterfield, John; Raghavan, Karthik; Fernandez, Daniel; Feldman, Marc D; Valvano, Jonathan W; Pearce, John A

    2006-01-01

    Real time left ventricular (LV) pressure-volume (P-V) loops have provided a framework for understanding cardiac mechanics in experimental animals and humans. Conductance measurements have been used for the past 25 years to generate an instantaneous left ventricular (LV) volume signal. The standard conductance method yields a combination of blood and ventricular muscle conductance; however, only the blood signal is used to estimate LV volume. The state of the art techniques like hypertonic saline injection and IVC occlusion, determine only a single steady-state value of the parallel conductance of the cardiac muscle. This is inaccurate, since the cardiac muscle component should vary instantaneously throughout the cardiac cycle as the LV contracts and fills, because the distance from the catheter to the muscle changes. The capacitive nature of cardiac muscle can be used to identify its contribution to the combined conductance signal. This method, in contrast to existing techniques, yields an instantaneous estimate of the parallel admittance of cardiac muscle that can be used to correct the measurement in real time. The corrected signal consists of blood conductance alone. We present the results of real time in vivo measurements of pressure-admittance and pressure-phase loops inside the murine left ventricle. We then use the magnitude and phase angle of the measured admittance to determine pressure volume loops inside the LV on a beat by beat basis. These results may be used to achieve a substantial improvement in the state of the art in this measurement method by eliminating the need for hypertonic saline injection. PMID:17946238

  12. Application of fiber Bragg grating sensors to real-time strain measurement of cryogenic tanks

    NASA Astrophysics Data System (ADS)

    Takeda, Nobuo; Mizutani, Tadahito; Hayashi, Kentaro; Okabe, Yoji

    2003-08-01

    Although many researches of strain measurement using fiber Bragg grating (FBG) sensors were conducted, there were few applications of FBG sensors to spacecraft in operation. It is very significant to develop an onboard system for the real-time strain measurement during the flight operation. In the present research, the real-time strain measurement of a composite liquid hydrogen (LH2) tank, which consisted of CFRP and aluminum liner, was attempted. Adhesive property of the FBG sensors was investigated first of all. As a result, UV coated FBG sensors and polyurethane adhesive were adopted. Then, reflection spectra from FBG sensors were measured through the tensile test at liquid helium (LHe) temperature. Since the center wavelength shifted in proportion to the applied strain, the FBG sensor was suitable as a precise strain sensor even at LHe temperature. Next, the development of an onboard FBG demodulator was discussed. This onboard demodulator was designed for weight saving to be mounted on a reusable rocket vehicle test (RVT) operated by the Institute of Space and Astronautical Science (ISAS). FBG sensors were bonded on the surface of the composite LH2 tank for the RVT. Then, strain measurement using the onboard demodulator was conducted through the cryogenic pressure test of the tank and compared with the result measured using the optical spectrum analyzer (OSA).

  13. Real-time measurement of skin erythema variation by negative compression: pilot study

    NASA Astrophysics Data System (ADS)

    Jung, Byungjo; Kim, Soobyeong; Bae, Yunjin; Kang, Heesung; Lee, Yongheum; Nelson, J. Stuart

    2012-08-01

    Skin erythema has been widely used as a diagnostic parameter in dermatology. This study describes a methodology for real-time measurement of skin erythema variation induced by negative compression. This study developed an optical measurement probe, which includes a RGB color sensor that translates in the vertical direction, with the magnitude of vertical translation dependening on the amount of skin deformation. Real-time measurement of erythema variation as a function of both negative compression and time was performed in vivo on 10 measurement sites located on the back of each of 12 volunteers who participated in this study. Negative compression was sequentially applied from -30 to -80 kPa and continuously at a constant magnitude (-80 kPa) condition. The results showed that skin erythema was uniformly induced at the measurement sites and linearly increased as a function of both negative compression and time. A wide range of individual variation was noted for skin erythema, which may be due to variations in anisotropic skin properties between volunteers. This study demonstrated the clinical feasibility of a novel optical device for skin erythema measurement. Future studies are needed to investigate the clinical applications of this device.

  14. Real-time measurement system for in-plane displacement and strain based on vision

    NASA Astrophysics Data System (ADS)

    Luo, Tao; Jin, Yi; Zhu, Ye; Zhai, Chao

    2013-08-01

    In this paper, combining optical measurement with conventional material testing machine, a real-time in-plane displacement and strain measurement system is built, which is applied to the material testing machine. This system can realize displacement and strain measurement of a large deformation sample moreover it can observe the sample crack on line. The change of displacement field is obtained through the change of center coordinate of each point of a grid lattice in the surface of the testing sample, according to two-dimensional sort coding for the grid in the traditional automated grid method, in this paper, an improved one-dimensional code method is adopted which make calculating speed much faster and the algorithm more adaptable. The measurement of the stability and precision of this system are made using the calibration board whose position precision is about 1.5 micron. The results show that the short-time stability of this system is about 0.5micron. At last, this system is used for strain measurement in a sample tension test, and the result shows that the system can acquire in-plane displacement and strain measurement results accurately and real-time, the velocity of image processing can reach 10 frame per second; or it can observe sample crack on line and storage the test process, the max velocity of observation and storage is 100 frame per second.

  15. Real-time direct measurement of diffraction efficiency of reflection gratings in photopolymer recording materials

    NASA Astrophysics Data System (ADS)

    Vojtíšek, Petr; Květoň, Milan

    2015-01-01

    Photopolymer recording systems have received a great deal of attention as a material for optical information storage and production of diffraction gratings. Before using these materials in such systems, it is important to characterize them and understand the processes which run during holographic recording, so that the recording itself can be optimized to obtain an efficient diffraction grating. In this contribution, we present a new method for real-time measurement of the diffraction response of reflection gratings during the recording process. Usually, the recording process in photopolymers is characterized by the real-time measurement of a transmission diffraction grating growth. This method does not allow measuring the growth of gratings with a very narrow spatial period in the reflection configuration. The new approach is based on the idea that the reflection grating is illuminated with white light at a different angle from the recording one and the diffraction efficiency is continuously measured with a spectrophotometer. Kogelnik's coupled wave theory is used as the theoretical background in this contribution. Experimentally, the photopolymer Bayfol HX has been tested in the reflection configuration and growth curves have been measured to show a good applicability of the detection method.

  16. NMDB: real-time database for high resolution neutron monitor measurements

    NASA Astrophysics Data System (ADS)

    Steigies, Christian

    The worldwide network of standardized neutron monitors is, after 50 years, still the stateof-the-art instrumentation to measure variations of the primary cosmic rays in the energy range 500 MeV-60 GeV. These measurements are an ideal complement to space based cosmic ray measurements. Unlike data from satellite experiments, neutron monitor data has never been available in high time resolution from many neutron monitor stations in real-time. The data is often available only from the individual station's website, in varying formats, and not in real-time. To overcome this deficit, the European Commission is supporting the Neutron Monitor database (NMDB) since January 2008 as an e-Infrastructures project in the Seventh Framework Programme in the Capacities section. Neutron Monitor stations that do not yet have 1-minute resolution will be supported by software and the development of an affordable standard registration system to submit the measurements to the database via internet in realtime. This resolves the problem of different data formats and for the first time allows use of realtime cosmic ray measurements for space weather applications. Besides creating a database and developing applications that use this data, a part of the project is dedicated to create a public outreach website to inform about cosmic rays and possible effects on humans, technological systems, and the environment.

  17. In-situ tryptophan-like fluorescence: A real-time indicator of faecal contamination in drinking water supplies.

    PubMed

    Sorensen, J P R; Lapworth, D J; Marchant, B P; Nkhuwa, D C W; Pedley, S; Stuart, M E; Bell, R A; Chirwa, M; Kabika, J; Liemisa, M; Chibesa, M

    2015-09-15

    Enteric pathogens are typically inferred from the presence of surrogate indicator organisms such as thermotolerant (faecal) coliforms (TTCs). The analysis of TTCs requires time-consuming incubation in suitable laboratories, which can limit sampling resolution, particularly during critical pollution events. Here, we demonstrate the use of in-situ fluorimeters targeting tryptophan-like compounds as a rapid, reagentless indicator of TTCs in groundwater-derived potable water supplies in Africa. A range of other common indicators of TTCs were also determined including nitrate, turbidity, and sanitary risk survey scores. Sampling was conducted during both the dry and wet seasons to investigate seasonality. Tryptophan-like fluorescence was the most effective predictor of both presence/absence and number of TTCs during both seasons. Seasonal changes in tryptophan-like fluorescence in deeper supplies suggest it is transported more efficiently through the aquifer than TTCs. Moreover, the perennial elevated concentrations in some wells suggest it is more resilient than TTCs in groundwater. Therefore tryptophan-like fluorescence could also be a better indicator of some smaller, more easily transported, and long-lived, pathogenic enteric viruses. These sensors have the potential to be included in real-time pollution alert systems for drinking water supplies throughout the world, as well as for mapping enteric pathogen risks in developing regions. PMID:26026711

  18. Real time kinetic flow cytometry measurements of cellular parameter changes evoked by nanosecond pulsed electric field.

    PubMed

    Orbán, Csaba; Pérez-García, Esther; Bajnok, Anna; McBean, Gethin; Toldi, Gergely; Blanco-Fernandez, Alfonso

    2016-05-01

    Nanosecond pulsed electric field (nsPEF) is a novel method to increase cell proliferation rate. The phenomenon is based on the microporation of cellular organelles and membranes. However, we have limited information on the effects of nsPEF on cell physiology. Several studies have attempted to describe the effects of this process, however no real time measurements have been conducted to date. In this study we designed a model system which allows the measurement of cellular processes before, during and after nsPEF treatment in real time. The system employs a Vabrema Mitoplicator(TM) nsPEF field generating instrument connected to a BD Accuri C6 cytometer with a silicon tube led through a peristaltic pump. This model system was applied to observe the effects of nsPEF in mammalian C6 glioblastoma (C6 glioma) and HEK-293 cell lines. Viability (using DRAQ7 dye), intracellular calcium levels (using Fluo-4 dye) and scatter characteristics were measured in a kinetic manner. Data were analyzed using the FACSKin software. The viability and morphology of the investigated cells was not altered upon nsPEF treatment. The response of HEK-293 cells to ionomycin as positive control was significantly lower in the nsPEF treated samples compared to non-treated cells. This difference was not observed in C6 cells. FSC and SSC values were not altered significantly by the nsPEF treatment. Our results indicate that this model system is capable of reliably investigating the effects of nsPEF on cellular processes in real time. © 2016 International Society for Advancement of Cytometry. PMID:26990601

  19. Real-Time Inhibitor Recession Measurements in Two Space Shuttle Reusable Solid Rocket Motors

    NASA Technical Reports Server (NTRS)

    McWhorter, B. B.; Ewing, M. E.; Bolton, D. E.; Albrechtsen, K. U.; Earnest, T. E.; Noble, T. C.; Longaker, M.

    2003-01-01

    Real-time internal motor insulation char line recession measurements have been evaluated for two full-scale static tests of the Space Shuttle Reusable Solid Rocket Motor (RSRM). These char line recession measurements were recorded on the forward facing propellant grain inhibitors to better understand the thermal performance of these inhibitors. The RSRM propellant grain inhibitors are designed to erode away during motor operation, thus making it difficult to use post-fire observations to determine inhibitor thermal performance. Therefore, this new internal motor instrumentation is invaluable in establishing an accurate understanding of inhibitor recession versus motor operation time. The data for the first test was presented at the 37th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit (AIAA 2001-3280) in July 2001. Since that time, a second full scale static test has delivered additional real-time data on inhibitor thermal performance. The evaluation of this data is presented in this paper. The second static test, in contrast to the first test, used a slightly different arrangement of instrumentation in the inhibitors. This instrumentation has yielded a better understanding of the inhibitor time dependent inboard tip recession. Graphs of inhibitor recession profiles with time are presented. Inhibitor thermal ablation models have been created from theoretical principals. The model predictions compare favorably with data from both tests. This verified modeling effort is important to support new inhibitor designs for a five segment Space Shuttle solid rocket motor. The internal instrumentation project on RSRM static tests is providing unique opportunities for other real-time internal motor measurements that could not otherwise be directly quantified.

  20. Real-time measurement of internal stress of dental tissue using holography

    NASA Astrophysics Data System (ADS)

    Pantelic, Dejan; Blazic, Larisa; Savic-Sevic, Svetlana; Muric, Branka; Vasiljevic, Darko; Panic, Bratimir; Belic, Ilija

    2007-05-01

    We describe a real-time holographic technique used to observe dental contraction due to photo-polymerization of dental filling during LED lamp illumination. An off-axis setup was used, with wet in-situ processing of the holographic plate, and consequent recording of interference fringes using CCD camera. Finite elements method was used to calculate internal stress of dental tissue, corresponding to experimentally measured deformation. A technique enables selection of preferred illumination method with reduced polymerization contraction. As a consequence, durability of dental filling might be significantly improved.

  1. Real time drift measurement for colloidal probe atomic force microscope: a visual sensing approach

    SciTech Connect

    Wang, Yuliang Bi, Shusheng; Wang, Huimin

    2014-05-15

    Drift has long been an issue in atomic force microscope (AFM) systems and limits their ability to make long time period measurements. In this study, a new method is proposed to directly measure and compensate for the drift between AFM cantilevers and sample surfaces in AFM systems. This was achieved by simultaneously measuring z positions for beads at the end of an AFM colloidal probe and on sample surface through an off-focus image processing based visual sensing method. The working principle and system configuration are presented. Experiments were conducted to validate the real time drift measurement and compensation. The implication of the proposed method for regular AFM measurements is discussed. We believe that this technique provides a practical and efficient approach for AFM experiments requiring long time period measurement.

  2. Real-time estimation of the structural response using limited measured data

    NASA Astrophysics Data System (ADS)

    Sedarat, Hassan; Talebinejad, Iman; Emami-Naeini, Abbas; Falck, David; van der Linden, Gwendolyn; Nobari, Farid; Krimotat, Alex; Lynch, Jerome

    2014-03-01

    This study introduces an efficient procedure to estimate the structural response of a suspension bridge in real-time based on a limited set of measured data. Unlike conventional techniques, the proposed procedure does not employ mode shapes and frequencies. In this study, the proposed technique is used to estimate the response of a suspension bridge structure based on a set of strain gauge measurements. Finite element analysis is performed only once to set up the structural parameters, namely computed flexibility matrix, and computed hanger forces matrix. The response of the bridge was estimated without any additional finite element analysis using the computed structural parameters and the measured hanger strains. The Alfred Zampa Memorial Bridge, on Interstate 80 in California, was selected for this study. A high fidelity finite element model of the bridge was developed using the general purpose computer program ADINA. The proposed method has been proven to have the capability to estimate any type of structural response in real time based on the measured hanger strains, and provides an important part of an integrated Structure Health Monitoring (SHM) system for major bridges.

  3. Real-Time Measurements of Aft Dome Insulation Erosion on Space Shuttle Reusable Solid Rocket Motor

    NASA Technical Reports Server (NTRS)

    McWhorter, Bruce; Ewing, Mark; Albrechtsen, Kevin; Noble, Todd; Longaker, Matt

    2004-01-01

    Real-time erosion of aft dome internal insulation was measured with internal instrumentation on a static test of a lengthened version of the Space Shuffle Reusable Solid Rocket Motor (RSRM). This effort marks the first time that real-time aft dome insulation erosion (Le., erosion due to the combined effects of thermochemical ablation and mechanical abrasion) was measured in this kind of large motor static test [designated as Engineering Test Motor number 3 (ETM3)I. This paper presents data plots of the erosion depth versus time. The data indicates general erosion versus time behavior that is in contrast to what would be expected from earlier analyses. Engineers have long known that the thermal environment in the aft dome is severe and that the resulting aft dome insulation erosion is significant. Models of aft dome erosion involve a two-step process of computational fluid dynamics (CFD) modeling and material ablation modeling. This modeling effort is complex. The time- dependent effects are difficult to verify with only prefire and postfire insulation measurements. Nozzle vectoring, slag accumulation, and changing boundary conditions will affect the time dependence of aft dome erosion. Further study of this data and continued measurements on future motors will increase our understanding of the aft dome flow and erosion environment.

  4. Flexible imaging payload for real-time fluorescent biological imaging in parabolic, suborbital and space analog environments

    NASA Astrophysics Data System (ADS)

    Bamsey, Matthew T.; Paul, Anna-Lisa; Graham, Thomas; Ferl, Robert J.

    2014-10-01

    utilized to assess, in real-time, the response of plants to novel environments including various spaceflight analogs, including several parabolic flight environments as well as hypobaric plant growth chambers. Basic performance results obtained under these operational environments, as well as laboratory-based tests are described. The Flex Imager has also been designed to be compatible with emerging suborbital platforms.

  5. A non-contact real-time measurement of lamp dimension based on machine vision

    NASA Astrophysics Data System (ADS)

    Song, Li-mei; Wang, Peng-qiang; Chang, Yu-lan; Li, Xiao-jie; Xi, Jiang-tao; Guo, Qing-hua; Li, Bing-nan

    2015-03-01

    In order to realize the online measurement of lamp dimension, the bulb image dimension measurement based on vision (BIDMV) is proposed. The image of lamp is obtained by camera. After image processing, such as Otsu algorithm, median filter, ellipse fitting and envelope rectangle fitting, the dimension of lamp can be calculated. Based on this method, a non-contact real-time measurement system of the lamp's dimension is developed. The precision of the proposed method is 0.07 mm, and it can satisfy the tolerance of the National Standard GB15766.1-2008. The experiment results show that the proposed method has a faster measuring speed and a higher precision compared with other measurement methods.

  6. Real-time analysis of multi-laser-beam fluorescence for timed control of laser tweezers in a microfluidic cell-sorting device

    NASA Astrophysics Data System (ADS)

    Davis, Lloyd M.; Lubbeck, Jennifer L.; Dean, Kevin M.; Palmer, Amy E.; Jimenez, Ralph

    2012-10-01

    We have developed a microfluidic cell sorter for mammalian cells expressing intrinsic fluorescent proteins that enables selection of cells with proteins that have enhanced photophysical properties, such as reduced fluorescence photobleaching and/or reversible dark state conversion. Previous ensemble imaging studies have used an acousto-optic modulator (AOM) to provide millisecond pulsed laser illumination for in vivo assays that distinguish reversible darkstate conversion from irreversible photobleaching. However, in the sorter, cells are hydrodynamically focused into a stream, which flows through a series of 4 or 8 line-focused, continuous, 532 nm laser beams, such that each cell experiences a similar millisecond modulated excitation. The amplitude and timing of the fluorescence response from each of the beams are measured by a red-sensitive photomultiplier and analyzed in real time to separately determine initial fluorescence brightness and photobleaching characteristics. In addition, each cell's flow speed is found from its time of passage through the beams, and if the analysis results are within adjustable limits, a 1064 nm optical trap beam is switched on and moved along an intersecting trajectory at a matching speed, so that the cell becomes deflected by the optical gradient forces towards another exit channel of the microfluidic device. The optical sorting of cells is similar to that demonstrated by others, except that the motion of the trap beam is achieved using a piezo mirror under computer control, rather than an AOM; also, rather than a single-beam brightness measure using a hardwired circuit, a more complex multi-beam analysis is performed in software using the Real-Time module of LabView (National Instruments) on a separate computer to achieve deterministic timing and low latency. The software displays updated statistics of the sort, obtained by counting cells that pass through an extra laser beam in the exit channel. A mixture of cells expressing

  7. Rethinking data collection and signal processing. 1. Real-time oversampling filter for chemical measurements.

    PubMed

    Laude, Nicholas D; Atcherley, Christopher W; Heien, Michael L

    2012-10-01

    Minimizing noise in chemical measurements is critical to achieve low limits of detection and accurate measurements. We describe a real-time oversampling filter that offers a method to reduce stochastic noise in a time-dependent chemical measurement. The power of this technique is demonstrated in its application to the separation of dopamine and serotonin by micellar electrokinetic chromatography with amperometric detection. Signal-to-noise ratios were increased by almost an order of magnitude, allowing for limits of detection of 100 and 120 amol, respectively. Real-time oversampling filters can be implemented using simple software algorithms and require no change to existing experimental apparatus. The application is not limited to analytical separations, and this technique can be used to improve the signal-to-noise ratio in any experiment where the necessary sampling rate is less than the maximum sampling rate of the analog-to-digital converter. Theory, implementation, and the performance of this filter are described. We propose that this technique should be the default mode of operation for an analog-to-digital converter. PMID:22978644

  8. GPU-assisted real-time three dimensional shape measurement by speckle-embedded fringe

    NASA Astrophysics Data System (ADS)

    Feng, Shijie; Chen, Qian; Zuo, Chao

    2015-07-01

    This paper presents a novel two-frame method of fringe projection for real-time, accurate and unambiguous threedimensional shape measurement. One of the used frames is a speckle pattern and the other one is a composite image which is fused by that speckle image and sinusoidal fringes. The sinusoidal component is used to retrieve the wrapped phase map. The frame of the speckle is employed to remove the phase ambiguity for the reconstruction of the absolute depth. Compared with traditional multi-frequency phase-shifting methods, the proposed scheme is of much lower sensitivity to movements as the result of the reduced number of used patterns. Moreover, its measuring precision is very close to that of the phase-shifting method, which indicates the method is of high accuracy. To process data in real time, a CUDA-enabled Graphics Processing Unit (GPU) is introduced to accelerate the computations of phase and depth. With our system, measurements can be performed at 21 frames per second with a resolution of 307K points per frame.

  9. Design and implementation of real-time LED spatial radiance measurement systems

    NASA Astrophysics Data System (ADS)

    Chang, Gao-Wei; Yeh, Zong-Mu; Liao, Chia-Cheng

    2007-02-01

    Light-emitting diodes (LEDs) have been recognized as a generation of new light sources because they possess the properties of energy-saving, environmental protection, long lifetime, and those lacking in conventional lighting. To satisfy the requirements for different applications (e.g., for large-scale displays), determining the spatial radiances of LEDs is important to identifying their viewing angle and utilizing their lighting efficiency. The objective of this paper is to build up a real-time spatial radiance measurement system for LEDs, on the basis of digital signal processing (DSP) techniques. In this paper, the system analysis is given to show the feasibility of this work. Two primary subsystems are devised to perform the real-time measurements. First, in the optoelectronic sensing and signal processing subsystem, a wide-bandwidth photodiode sensing circuit is employed to acquire optical signals at a high speed, and an automatic gain control (AGC) circuit is designed to increase the measurement range. To support high-speed data processing, a DSP-based platform is developed in the subsystem. Second, a light-source rotation scheme is used in the optomechanical subsystem. For performance evaluations, we adopt a standard calibrating light source to test and verify our system. Experimental results indicate that the proposed system gives satisfactory results.

  10. A Real-Time Measurement System for Long-Life Flood Monitoring and Warning Applications

    PubMed Central

    Marin-Perez, Rafael; García-Pintado, Javier; Gómez, Antonio Skarmeta

    2012-01-01

    A flood warning system incorporates telemetered rainfall and flow/water level data measured at various locations in the catchment area. Real-time accurate data collection is required for this use, and sensor networks improve the system capabilities. However, existing sensor nodes struggle to satisfy the hydrological requirements in terms of autonomy, sensor hardware compatibility, reliability and long-range communication. We describe the design and development of a real-time measurement system for flood monitoring, and its deployment in a flash-flood prone 650 km2 semiarid watershed in Southern Spain. A developed low-power and long-range communication device, so-called DatalogV1, provides automatic data gathering and reliable transmission. DatalogV1 incorporates self-monitoring for adapting measurement schedules for consumption management and to capture events of interest. Two tests are used to assess the success of the development. The results show an autonomous and robust monitoring system for long-term collection of water level data in many sparse locations during flood events. PMID:22666028

  11. Monitoring and simulating real-time electric power system operation with phasor measurements

    SciTech Connect

    Phadke, A.G.; Thorp, J.S.

    1995-01-01

    In this research project, two important results have been achieved. The concept of generator axis load flow has been developed more fully, and has been tested through simulations on the 39-bus system (with 10 generators). Generator axis load flow is a load flow calculation which views the entire network from a few retained buses such as the internal nodes of the generators. As these nodes can be indirectly monitored in real time through phasor measurements of generator terminal quantities, it becomes possible to track and predict the behavior of the entire network from these few observation points. This is extremely valuable in the task of predicting network instability in real time. The task of instability prediction of a multi-machine power system is one of the most difficult analytical exercises. We investigated two of the most promising approaches: the extended equal area method, and the transient energy function method. Although both of these methods work well in many instances, we have shown that in other cases, the predictions made by the two methods are incorrect. The failure of the methods can be traced to their inability to deal with the behavior of the system after the first turning point of the motor swing curves. Instead of using these methods, we propose the direct integration of the machine swing equations following the start of a disturbance. Coupled with the generator aids load flow developed above, and using the high speed computers available now, we show that for systems of significant size (39 bus system), accurate predictions through direct computation are possible. The report also includes results on computational efficiency of the method of faster-than-real-time integration using machine equations and the generator aids load flow. It is anticipated that this technique will be useful in most practical applications in power system control centers of the future.

  12. [Measuring leg length and leg length difference with the method of real time sonography].

    PubMed

    Holst, A; Thomas, W

    1988-06-01

    A brief presentation of the clinical and radiological methods to measure the leg length and the leg length difference is followed by an outline of the new diagnostic method for measuring the leg length and the leg length difference by means of real-time sonography. Tests conducted on corpses, as well as clinical examples, show that sonography is an ideal method for determining the exact lengths of the femur and tibia. The joint gaps on the hip joint, knee joint and upper ankle joint can be visualised by means of a 5 MHz linear scanner. A 1 mm strong metal bar on the skin and under the scanner are positioned at a right angle to the longitudinal axis of the body so that the bar can be seen in the centre of each joint gap by means of real-time sonography. A measuring device gives the distances of the joint gaps in cm so that the differences correspond to the real length of femur and tibia. This standardised measuring procedure is done by a specially developed bearing and measuring device. The results of the sonographical measurings on 20 corpses and checking after consecutive dissections showed in 75% of the cases a 100% sonographic measuring accuracy of the total leg length. The separately considered results for femur (85%) and tibia (90%) were even better. The maximum sonographic measuring fault was 1.0 cm for the femur (in one case) and 0.5 cm for the tibia, respectively. Thus, sonographic measuring of the leg length offers a reliable, non-invasive and easily performed new method that can be repeated any number of times. It is ideal for the development control of therapeutically influenced as well as spontaneous transformations of leg length differences. PMID:3071879

  13. Obtaining Reliable Predictions of Terrestrial Energy Coupling From Real-Time Solar Wind Measurements

    NASA Technical Reports Server (NTRS)

    Weimer, Daniel R.

    2002-01-01

    Measurements of the interplanetary magnetic field (IMF) from the ACE (Advanced Composition Explorer), Wind, IMP-8 (Interplanetary Monitoring Platform), and Geotail spacecraft have revealed that the IMF variations are contained in phase planes that are tilted with respect to the propagation direction, resulting in continuously variable changes in propagation times between spacecraft, and therefore, to the Earth. Techniques for using 'minimum variance analysis' have been developed in order to be able to measure the phase front tilt angles, and better predict the actual propagation times from the L1 orbit to the Earth, using only the real-time IMF measurements from one spacecraft. The use of empirical models with the IMF measurements at L1 from ACE (or future satellites) for predicting 'space weather' effects has also been demonstrated.

  14. Using Indirect Turbulence Measurements for Real-Time Parameter Estimation in Turbulent Air

    NASA Technical Reports Server (NTRS)

    Martos, Borja; Morelli, Eugene A.

    2012-01-01

    The use of indirect turbulence measurements for real-time estimation of parameters in a linear longitudinal dynamics model in atmospheric turbulence was studied. It is shown that measuring the atmospheric turbulence makes it possible to treat the turbulence as a measured explanatory variable in the parameter estimation problem. Commercial off-the-shelf sensors were researched and evaluated, then compared to air data booms. Sources of colored noise in the explanatory variables resulting from typical turbulence measurement techniques were identified and studied. A major source of colored noise in the explanatory variables was identified as frequency dependent upwash and time delay. The resulting upwash and time delay corrections were analyzed and compared to previous time shift dynamic modeling research. Simulation data as well as flight test data in atmospheric turbulence were used to verify the time delay behavior. Recommendations are given for follow on flight research and instrumentation.

  15. Hands-free, Wireless Goggles for Near-infrared Fluorescence and Real-time Image-guided Surgery

    PubMed Central

    Liu, Yang; Bauer, Adam Q.; Akers, Walter; Sudlow, Gail; Liang, Kexian; Shen, Duanwen; Berezin, Mikhail; Culver, Joseph P.; Achilefu, Samuel

    2011-01-01

    Background Current cancer management faces several challenges, including the occurrence of residual tumor after resection, the use of radioactive materials or high concentrations of blue dyes for sentinel lymph node (SLN) biopsy, and use of bulky systems in surgical suites for image guidance. To overcome these limitations, we developed a real-time intraoperative imaging device that, when combined with near infrared (NIR) fluorescent molecular probes, can aid identification of tumor margins, guide surgical resections, map SLNs, and transfer acquired data wirelessly for remote analysis. Methods We developed a new compact, wireless, wearable, and battery-operated device that allows hands-free operation by surgeons. A CCD-based consumer-grade night vision viewer was used to develop the detector portion of the device and the light source portion was developed from a compact headlamp. This piece was retrofitted to provide both NIR excitation and white light illumination simultaneously. Wireless communication was enabled by integrating a battery-operated miniature radio-frequency video transmitter into the system. We applied the device in several types of oncologic surgical procedures in murine models, including SLN mapping, fluorescence-guided tumor resection, and surgery under remote expert guidance. Results Unlike conventional imaging instruments, the device directly displays fluorescence information on its eyepiece. When employed in SLN mapping, the locations of SLNs were clearly visualized, even with tracer level dosing of a NIR fluorescent dye, indocyanine green. When utilized in tumor resection, tumor margins and small nodules not visible to the naked eye were readily visualized. In a simulated point-of-care setting, tumors were successfully located and removed under remote guidance using the wireless feature of the device. Importantly, the total cost of this prototype system ($1200) is significantly lower than existing imaging instruments. Conclusion Our results

  16. Real-time analysis of metabolic activity within Lactobacillus acidophilus by phasor fluorescence lifetime imaging microscopy of NADH.

    PubMed

    Torno, Keenan; Wright, Belinda K; Jones, Mark R; Digman, Michelle A; Gratton, Enrico; Phillips, Michael

    2013-04-01

    Nicotinamide adenine dinucleotide (NADH) is an endogenous fluorescent molecule commonly used as a metabolic biomarker. Fluorescence lifetime imaging microscopy (FLIM) is a method in which the fluorescence decay is measured at each pixel of an image. While the fluorescence spectrum of free and protein-bound NADH is very similar, free and protein-bound NADH display very different decay profiles. Therefore, FLIM can provide a way to distinguish free/bound NADH at the level of single bacteria within biological samples. The phasor technique is a graphical method to analyse the entire image and to produce a histogram of pixels with different decay profile. In this study, NADH fluorescence decay profiles within Lactobacillus acidophilus samples treated using different protocols indicated discernible variations. Clear distinctions between fluorescence decay profiles of NADH in samples of artificially heightened metabolic activity in comparison to those of samples lacking an accessible carbon source were obtained. PMID:23233088

  17. Real-time high-resolution heterodyne-based measurements of spectral dynamics in fibre lasers

    PubMed Central

    Sugavanam, Srikanth; Fabbri, Simon; Le, Son Thai; Lobach, Ivan; Kablukov, Sergey; Khorev, Serge; Churkin, Dmitry

    2016-01-01

    Conventional tools for measurement of laser spectra (e.g. optical spectrum analysers) capture data averaged over a considerable time period. However, the generation spectrum of many laser types may involve spectral dynamics whose relatively fast time scale is determined by their cavity round trip period, calling for instrumentation featuring both high temporal and spectral resolution. Such real-time spectral characterisation becomes particularly challenging if the laser pulses are long, or they have continuous or quasi-continuous wave radiation components. Here we combine optical heterodyning with a technique of spatio-temporal intensity measurements that allows the characterisation of such complex sources. Fast, round-trip-resolved spectral dynamics of cavity-based systems in real-time are obtained, with temporal resolution of one cavity round trip and frequency resolution defined by its inverse (85 ns and 24 MHz respectively are demonstrated). We also show how under certain conditions for quasi-continuous wave sources, the spectral resolution could be further increased by a factor of 100 by direct extraction of phase information from the heterodyned dynamics or by using double time scales within the spectrogram approach. PMID:26984634

  18. Real-time setup to measure radon emission during rock deformation: implications for geochemical surveillance

    NASA Astrophysics Data System (ADS)

    Tuccimei, P.; Mollo, S.; Soligo, M.; Scarlato, P.; Castelluccio, M.

    2015-05-01

    Laboratory experiments can represent a valid approach to unravel the complex interplay between the geochemical behaviour of radon and rock deformation mechanisms. In light of this, we present a new real-time experimental setup for analysing in continuum the alpha-emitting 222Rn and 220Rn daughters over variable stress-strain regimes. The most innovative segment of this setup consists of the radon accumulation chamber obtained from a tough and durable material that can host large cylindrical rock samples. The accumulation chamber is connected, in a closed-loop configuration, to a gas-drying unit and to a RAD7 radon monitor. A recirculating pump moves the gas from the rock sample to a solid-state detector for alpha counting of radon and thoron progeny. The measured radon signal is enhanced by surrounding the accumulation chamber with a digitally controlled heating belt. As the temperature is increased, the number of effective collisions of radon atoms increases favouring the diffusion of radon through the material and reducing the analytical uncertainty. The accumulation chamber containing the sample is then placed into a uniaxial testing apparatus where the axial deformation is measured throughout a linear variable displacement transducer. A dedicated software allows obtaining a variety of stress-strain regimes from fast deformation rates to long-term creep tests. Experiments conducted with this new real-time setup have important ramifications for the interpretation of geochemical anomalies recorded prior to volcanic eruptions or earthquakes.

  19. Strengthening HIV surveillance: measurements to track the epidemic in real time.

    PubMed

    Buthelezi, Usangiphile E; Davidson, Candace L; Kharsany, Ayesha Bm

    2016-07-01

    Surveillance for HIV as a public health initiative requires timely, detailed and robust data to systematically understand burden of infection, transmission patterns, direct prevention efforts, guide funding, identify new infections and predict future trends in the epidemic. The methods for HIV surveillance have evolved to reliably track the epidemic and identify new infections in real time. Initially HIV surveillance relied primarily on the reporting of AIDS cases followed by measuring antibodies to HIV to determine prevalence in key populations. With the roll-out of antiretroviral therapy (ART) resulting in better survival and the corresponding increase in HIV prevalence, the landscape of surveillance shifted further to track HIV prevalence and incidence within the context of programmes. Recent developments in laboratory assays that potentially measure and differentiate recent versus established HIV infection offer a cost-effective method for the rapid estimation of HIV incidence. These tests continue to be validated and are increasingly useful in informing the status of the epidemic in real time. Surveillance of heterogeneity of infections contributing to sub-epidemics requires methods to identify affected populations, density, key geographical locations and phylogenetically linked or clustered infections. Such methods could provide a nuanced understanding of the epidemic and prioritise prevention efforts to those most vulnerable. This paper brings together recent developments and challenges facing HIV surveillance, together with the application of newer assays and methods to fast-track the HIV prevention and treatment response. PMID:27399039

  20. In situ real-time measurement of physical characteristics of airborne bacterial particles

    NASA Astrophysics Data System (ADS)

    Jung, Jae Hee; Lee, Jung Eun

    2013-12-01

    Bioaerosols, including aerosolized bacteria, viruses, and fungi, are associated with public health and environmental problems. One promising control method to reduce the harmful effects of bioaerosols is thermal inactivation via a continuous-flow high-temperature short-time (HTST) system. However, variations in bioaerosol physical characteristics - for example, the particle size and shape - during the continuous-flow inactivation process can change the transport properties in the air, which can affect particle deposition in the human respiratory system or the filtration efficiency of ventilation systems. Real-time particle monitoring techniques are a desirable alternative to the time-consuming process of microscopic analysis that is conventionally used in sampling and particle characterization. Here, we report in situ real-time optical scattering measurements of the physical characteristics of airborne bacteria particles following an HTST process in a continuous-flow system. Our results demonstrate that the aerodynamic diameter of bacterial aerosols decreases when exposed to a high-temperature environment, and that the shape of the bacterial cells is significantly altered. These variations in physical characteristics using optical scattering measurements were found to be in agreement with the results of scanning electron microscopy analysis.

  1. Toward Real-Time Automated Detection of Turns during Gait Using Wearable Inertial Measurement Units

    PubMed Central

    Novak, Domen; Goršič, Maja; Podobnik, Janez; Munih, Marko

    2014-01-01

    Previous studies have presented algorithms for detection of turns during gait using wearable sensors, but those algorithms were not built for real-time use. This paper therefore investigates the optimal approach for real-time detection of planned turns during gait using wearable inertial measurement units. Several different sensor positions (head, back and legs) and three different detection criteria (orientation, angular velocity and both) are compared with regard to their ability to correctly detect turn onset. Furthermore, the different sensor positions are compared with regard to their ability to predict the turn direction and amplitude. The evaluation was performed on ten healthy subjects who performed left/right turns at three amplitudes (22, 45 and 90 degrees). Results showed that turn onset can be most accurately detected with sensors on the back and using a combination of orientation and angular velocity. The same setup also gives the best prediction of turn direction and amplitude. Preliminary measurements with a single amputee were also performed and highlighted important differences such as slower turning that need to be taken into account. PMID:25310470

  2. Optimized quantum sensing with a single electron spin using real-time adaptive measurements

    NASA Astrophysics Data System (ADS)

    Bonato, C.; Blok, M. S.; Dinani, H. T.; Berry, D. W.; Markham, M. L.; Twitchen, D. J.; Hanson, R.

    2016-03-01

    Quantum sensors based on single solid-state spins promise a unique combination of sensitivity and spatial resolution. The key challenge in sensing is to achieve minimum estimation uncertainty within a given time and with high dynamic range. Adaptive strategies have been proposed to achieve optimal performance, but their implementation in solid-state systems has been hindered by the demanding experimental requirements. Here, we realize adaptive d.c. sensing by combining single-shot readout of an electron spin in diamond with fast feedback. By adapting the spin readout basis in real time based on previous outcomes, we demonstrate a sensitivity in Ramsey interferometry surpassing the standard measurement limit. Furthermore, we find by simulations and experiments that adaptive protocols offer a distinctive advantage over the best known non-adaptive protocols when overhead and limited estimation time are taken into account. Using an optimized adaptive protocol we achieve a magnetic field sensitivity of 6.1 ± 1.7 nT Hz-1/2 over a wide range of 1.78 mT. These results open up a new class of experiments for solid-state sensors in which real-time knowledge of the measurement history is exploited to obtain optimal performance.

  3. Complexity-Measure-Based Sequential Hypothesis Testing for Real-Time Detection of Lethal Cardiac Arrhythmias

    NASA Astrophysics Data System (ADS)

    Chen, Szi-Wen

    2006-12-01

    A novel approach that employs a complexity-based sequential hypothesis testing (SHT) technique for real-time detection of ventricular fibrillation (VF) and ventricular tachycardia (VT) is presented. A dataset consisting of a number of VF and VT electrocardiogram (ECG) recordings drawn from the MIT-BIH database was adopted for such an analysis. It was split into two smaller datasets for algorithm training and testing, respectively. Each ECG recording was measured in a 10-second interval. For each recording, a number of overlapping windowed ECG data segments were obtained by shifting a 5-second window by a step of 1 second. During the windowing process, the complexity measure (CM) value was calculated for each windowed segment and the task of pattern recognition was then sequentially performed by the SHT procedure. A preliminary test conducted using the database produced optimal overall predictive accuracy of[InlineEquation not available: see fulltext.]. The algorithm was also implemented on a commercial embedded DSP controller, permitting a hardware realization of real-time ventricular arrhythmia detection.

  4. A robust adaptive denoising framework for real-time artifact removal in scalp EEG measurements

    NASA Astrophysics Data System (ADS)

    Kilicarslan, Atilla; Grossman, Robert G.; Contreras-Vidal, Jose Luis

    2016-04-01

    Objective. Non-invasive measurement of human neural activity based on the scalp electroencephalogram (EEG) allows for the development of biomedical devices that interface with the nervous system for scientific, diagnostic, therapeutic, or restorative purposes. However, EEG recordings are often considered as prone to physiological and non-physiological artifacts of different types and frequency characteristics. Among them, ocular artifacts and signal drifts represent major sources of EEG contamination, particularly in real-time closed-loop brain-machine interface (BMI) applications, which require effective handling of these artifacts across sessions and in natural settings. Approach. We extend the usage of a robust adaptive noise cancelling (ANC) scheme ({H}∞ filtering) for removal of eye blinks, eye motions, amplitude drifts and recording biases simultaneously. We also characterize the volume conduction, by estimating the signal propagation levels across all EEG scalp recording areas due to ocular artifact generators. We find that the amplitude and spatial distribution of ocular artifacts vary greatly depending on the electrode location. Therefore, fixed filtering parameters for all recording areas would naturally hinder the true overall performance of an ANC scheme for artifact removal. We treat each electrode as a separate sub-system to be filtered, and without the loss of generality, they are assumed to be uncorrelated and uncoupled. Main results. Our results show over 95-99.9% correlation between the raw and processed signals at non-ocular artifact regions, and depending on the contamination profile, 40-70% correlation when ocular artifacts are dominant. We also compare our results with the offline independent component analysis and artifact subspace reconstruction methods, and show that some local quantities are handled better by our sample-adaptive real-time framework. Decoding performance is also compared with multi-day experimental data from 2 subjects

  5. Proposed Methods for Real-Time Measurement of Posterior Condylar Angle during TKA

    PubMed Central

    Behera, Prateek; Prakash, Mahesh; Dhillon, Mandeep

    2014-01-01

    Purpose Conventional instruments are known to result in high numbers of outliers in restoring femoral component rotation primarily due to fixed degree of external rotation resection relative to the posterior condylar line (PCL). Outliers can be reduced by determining the patient specific posterior condylar angle (PCA) preoperatively or intraoperatively. There is a paucity of methods that can be used during surgery for determining the PCA. We propose two simple, real-time methods to determine the PCA and hence to measure the axial anatomical variation during surgery. Materials and Methods The study was conducted using axial computed tomography (CT) scans of the knees of 26 patients. The commercial software K-PACS and our proposed two methods (trigonometric and protractor) were used to measure the angle between the transepicondylar axis and PCL, i.e., PCA. Statistical comparison between the mean angles obtained by K-PACS and our methods were done. Results The three methods resulted in similar PCAs. The mean PCA measured by the three methods were similar. The mean PCA value measured by the K-PACS, trigonometric method and protractor method was 6.27° (range, 0° to 12°), 6.23° (range, 0° to 11.11°) and 6.31° (range, 0° to 12°), respectively. There were significant correlations between the K-PACS measured PCA and trigonometrically or protractor measured PCA. Conclusions Our novel, simple, easily reproducible, real-time and radiation-free PCA measurement methods obviate the need for preoperative CT scan for identification of patient specific PCA. PMID:25505705

  6. Navigation surgery for intraoperative sentinel lymph node detection using Indocyanine green (ICG) fluorescence real-time imaging in breast cancer.

    PubMed

    Toh, U; Iwakuma, N; Mishima, M; Okabe, M; Nakagawa, S; Akagi, Y

    2015-09-01

    A new sensitive fluorescence imaging system was developed for the real-time identification of sentinel lymph nodes (SLNs) in patients with early breast cancer. The purpose of this study was to evaluate the utility of a color charge-coupled device camera system for the intraoperative detection of SLNs and to determine its clinical efficacy and sensitivity in patients with operable breast cancer. We assessed a total of 168 patients diagnosed with or suspected of having early-stage breast cancer without metastasis in SLNs. The intraoperative detection of SLNs was performed using the conventional Indigo Carmine dye (indigotindisulfonate sodium) technique combined with a new Indocyanine green (ICG) imaging system (HyperEye Medical System: HEMS, MIZUHO IKAKOGYO, Japan) to map SLNs, in which the lymphatic vessels and SLNs were visualized transcutaneously with illuminating ICG fluorescence. Between January 2012 and May 2013, SLNs were successfully identified in all 168 patients (detection rate: 100%). By histopathology, the sensitivity was 93.8% for the detection of the metastatic involvement of SLNs (15 of 16 nodal-positive patients). After a median follow-up of 30.5 months, none of the patients presented with axillary recurrence. These results suggest that the HEMS imaging system is a feasible and effective method for the detection of SLNs in breast cancer. Furthermore, the HEMS device permitted the transcutaneous visualization of lymphatic vessels under light conditions, thus facilitating the identification and detection of SLNs without affecting the surgical procedure, together with a high sensitivity and specificity. PMID:26267663

  7. Early detection of Trichinella spiralis in muscle of infected mice by real-time fluorescence resonance energy transfer PCR.

    PubMed

    Tantrawatpan, Chairat; Intapan, Pewpan M; Thanchomnang, Tongjit; Sanpool, Oranuch; Janwan, Penchom; Boonmars, Thidarut; Morakote, Nimit; Maleewong, Wanchai

    2013-09-01

    Real-time fluorescence resonance energy transfer (FRET) PCR and melting curve analysis using newly developed fluorophore-labeled hybridization probes were applied for the detection of Trichinella spiralis DNA in muscle of mice following oral inoculation with 300 T. spiralis larvae. The developed assay could detect and differentiate T. spiralis, Trichinella papuae, and Trichinella pseudospiralis DNAs by the different melting temperatures (Tm). The assay had a detection limit of 5 × 10(2) positive control plasmid copies, which was equivalent to 1 ng of T. spiralis DNA spiked into 250 mg of muscle sample. No fluorescence signal was detected when the technique was applied to the DNA of 27 parasites other than Trichinella spp. The assay could detect T. spiralis DNA in muscle at 7, 14, and 21 days postinoculation. The range, mean ± standard deviation, and median of the Tm values of all positive muscle tissue samples were 60.4-60.8, 60.6 ± 0.2, and 60.5, respectively. This assay provides an effective tool for the specific, sensitive, and high-throughput detection of T. spiralis DNA in muscle during the early stage of infection. In addition, the technique can be useful for epidemiologic surveillance in naturally infected wildlife. PMID:23808975

  8. Early Detection of Trichinella spiralis in Muscle of Infected Mice by Real-Time Fluorescence Resonance Energy Transfer PCR

    PubMed Central

    Tantrawatpan, Chairat; Intapan, Pewpan M.; Thanchomnang, Tongjit; Sanpool, Oranuch; Janwan, Penchom; Boonmars, Thidarut; Morakote, Nimit

    2013-01-01

    Abstract Real-time fluorescence resonance energy transfer (FRET) PCR and melting curve analysis using newly developed fluorophore-labeled hybridization probes were applied for the detection of Trichinella spiralis DNA in muscle of mice following oral inoculation with 300 T. spiralis larvae. The developed assay could detect and differentiate T. spiralis, Trichinella papuae, and Trichinella pseudospiralis DNAs by the different melting temperatures (Tm). The assay had a detection limit of 5×102 positive control plasmid copies, which was equivalent to 1 ng of T. spiralis DNA spiked into 250 mg of muscle sample. No fluorescence signal was detected when the technique was applied to the DNA of 27 parasites other than Trichinella spp. The assay could detect T. spiralis DNA in muscle at 7, 14, and 21 days postinoculation. The range, mean±standard deviation, and median of the Tm values of all positive muscle tissue samples were 60.4–60.8, 60.6±0.2, and 60.5, respectively. This assay provides an effective tool for the specific, sensitive, and high-throughput detection of T. spiralis DNA in muscle during the early stage of infection. In addition, the technique can be useful for epidemiologic surveillance in naturally infected wildlife. PMID:23808975

  9. Application of real-time digitization techniques in beam measurement for accelerators

    NASA Astrophysics Data System (ADS)

    Zhao, Lei; Zhan, Lin-Song; Gao, Xing-Shun; Liu, Shu-Bin; An, Qi

    2016-04-01

    Beam measurement is very important for accelerators. In this paper, modern digital beam measurement techniques based on IQ (In-phase & Quadrature-phase) analysis are discussed. Based on this method and high-speed high-resolution analog-to-digital conversion, we have completed three beam measurement electronics systems designed for the China Spallation Neutron Source (CSNS), Shanghai Synchrotron Radiation Facility (SSRF), and Accelerator Driven Sub-critical system (ADS). Core techniques of hardware design and real-time system calibration are discussed, and performance test results of these three instruments are also presented. Supported by National Natural Science Foundation of China (11205153, 10875119), Knowledge Innovation Program of the Chinese Academy of Sciences (KJCX2-YW-N27), and the Fundamental Research Funds for the Central Universities (WK2030040029),and the CAS Center for Excellence in Particle Physics (CCEPP).

  10. Real-time measurement of quasiparticle tunneling in a single-junction transmon qubit using feedback

    NASA Astrophysics Data System (ADS)

    Ristè, Diego; Bultink, Niels; Tiggelman, Marijn; Schouten, Raymond; Lehnert, Konrad; Dicarlo, Leonardo

    2013-03-01

    With coherence times of superconducting qubits now exceeding 100 μs , the contribution of quasiparticle (QP) tunneling to qubit relaxation and dephasing becomes potentially relevant. We report the real-time measurement of QP tunneling across the single junction of a 3D transmon qubit. We integrate recent developments in projective qubit readout with 99 % fidelity and feedback-based reset to transform the qubit into a charge-parity detector with 6 μs resolution. We detect a symmetric random telegraph signal matching a QP tunneling time of 0 . 8 ms . By measuring the correlation function of charge parity conditioned on specific initial and final qubit states, we determine that most QP tunneling does not induce qubit transitions, in contradiction with recent theory. We extract a QP-induced qubit relaxation time T1qp ~ 3 ms , decidedly not limiting the measured T1 = 0 . 14 ms . Research supported by NWO, FOM, and EU Project SOLID.

  11. Advanced video extensometer for non-contact, real-time, high-accuracy strain measurement.

    PubMed

    Pan, Bing; Tian, Long

    2016-08-22

    We developed an advanced video extensometer for non-contact, real-time, high-accuracy strain measurement in material testing. In the established video extensometer, a "near perfect and ultra-stable" imaging system, combining the idea of active imaging with a high-quality bilateral telecentric lens, is constructed to acquire high-fidelity video images of the test sample surface, which is invariant to ambient lighting changes and small out-of-plane motions occurred between the object surface and image plane. In addition, an efficient and accurate inverse compositional Gauss-Newton algorithm incorporating a temporal initial guess transfer scheme and a high-accuracy interpolation method is employed to achieve real-time, high-accuracy displacement tracking with negligible bias error. Tensile tests of an aluminum sample and a carbon fiber filament sample were performed to demonstrate the efficiency, repeatability and accuracy of the developed advanced video extensometer. The results indicate that longitudinal and transversal strains can be estimated and plotted at a rate of 117 fps and with a maximum strain error less than 30 microstrains. PMID:27557188

  12. Real-time Image Analysis of Living Cellular-Biology Measurements of Intelligent Chemistry

    SciTech Connect

    Solinsky, James C.; Budge, Scott E.; Majors, Paul D.; Rex, Bruce B.

    2003-08-01

    This paper reports on the Pacific Northwest National Laboratory (PNNL) DOE Initiative in Image Science and Technology (ISAT) research, which is developing algorithms and software tool sets for remote sensing and biological applications. In particular, the PNNL ISAT work is applying these research results to the automated analysis of real-time cellular biology imagery to assist the biologist in determining the correct data collection region for the current state of a conglomerate of living cells in three-dimensional motion. The real-time computation of the typical 120 MB/sec multi-spectral data sets is executed in a Field Programmable Gate Array (FPGA) technology, which has very high processing rates due to large-scale parallelism. The outcome of this artificial vision work will allow the biologist to work with imagery as a creditable set of dye-tagged chemistry measurements in formats for individual cell tracking through regional feature extraction, and animation visualization through individual object isolation/characterization of the microscopy imagery.

  13. Real-time dual-loop electric current measurement for label-free nanofluidic preconcentration chip.

    PubMed

    Chung, Pei-Shan; Fan, Yu-Jui; Sheen, Horn-Jiunn; Tian, Wei-Cheng

    2015-01-01

    An electrokinetic trapping (EKT)-based nanofluidic preconcentration device with the capability of label-free monitoring trapped biomolecules through real-time dual-loop electric current measurement was demonstrated. Universal current-voltage (I-V) curves of EKT-based preconcentration devices, consisting of two microchannels connected by ion-selective channels, are presented for functional validation and optimal operation; universal onset current curves indicating the appearance of the EKT mechanism serve as a confirmation of the concentrating action. The EKT mechanism and the dissimilarity in the current curves related to the volume flow rate (Q), diffusion coefficient (D), and diffusion layer (DL) thickness were explained by a control volume model with a five-stage preconcentration process. Different behaviors of the trapped molecular plug were categorized based on four modes associated with different degrees of electroosmotic instability (EOI). A label-free approach to preconcentrating (bio)molecules and monitoring the multibehavior molecular plug was demonstrated through real-time electric current monitoring, rather than through the use of microscope images. PMID:25372369

  14. Adapting CALIPSO Climate Measurements for Near Real Time Analyses and Forecasting

    NASA Technical Reports Server (NTRS)

    Vaughan, Mark A.; Trepte, Charles R.; Winker, David M.; Avery, Melody A.; Campbell, James; Hoff, Ray; Young, Stuart; Getzewich, Brian J.; Tackett, Jason L.; Kar, Jayanta

    2011-01-01

    The Cloud-Aerosol Lidar and Infrared Pathfinder satellite Observations (CALIPSO) mission was originally conceived and designed as a climate measurements mission, with considerable latency between data acquisition and the release of the level 1 and level 2 data products. However, the unique nature of the CALIPSO lidar backscatter profiles quickly led to the qualitative use of CALIPSO?s near real time (i.e., ? expedited?) lidar data imagery in several different forecasting applications. To enable quantitative use of their near real time analyses, the CALIPSO project recently expanded their expedited data catalog to include all of the standard level 1 and level 2 lidar data products. Also included is a new cloud cleared level 1.5 profile product developed for use by operational forecast centers for verification of aerosol predictions. This paper describes the architecture and content of the CALIPSO expedited data products. The fidelity and accuracy of the expedited products are assessed via comparisons to the standard CALIPSO data products.

  15. Dissolution Dynamic Nuclear Polarization Instrumentation for Real-time Enzymatic Reaction Rate Measurements by NMR.

    PubMed

    Balzan, Riccardo; Fernandes, Laetitia; Comment, Arnaud; Pidial, Laetitia; Tavitian, Bertrand; Vasos, Paul R

    2016-01-01

    The main limitation of NMR-based investigations is low sensitivity. This prompts for long acquisition times, thus preventing real-time NMR measurements of metabolic transformations. Hyperpolarization via dissolution DNP circumvents part of the sensitivity issues thanks to the large out-of-equilibrium nuclear magnetization stemming from the electron-to-nucleus spin polarization transfer. The high NMR signal obtained can be used to monitor chemical reactions in real time. The downside of hyperpolarized NMR resides in the limited time window available for signal acquisition, which is usually on the order of the nuclear spin longitudinal relaxation time constant, T1, or, in favorable cases, on the order of the relaxation time constant associated with the singlet-state of coupled nuclei, TLLS. Cellular uptake of endogenous molecules and metabolic rates can provide essential information on tumor development and drug response. Numerous previous hyperpolarized NMR studies have demonstrated the relevancy of pyruvate as a metabolic substrate for monitoring enzymatic activity in vivo. This work provides a detailed description of the experimental setup and methods required for the study of enzymatic reactions, in particular the pyruvate-to-lactate conversion rate in presence of lactate dehydrogenase (LDH), by hyperpolarized NMR. PMID:26967906

  16. Real-Time Protein and Cell Binding Measurements on Hydroxyapatite Coatings.

    PubMed

    Vilardell, A M; Cinca, N; Jokinen, A; Garcia-Giralt, N; Dosta, S; Cano, I G; Guilemany, J M

    2016-01-01

    Although a lot of in vitro and in vivo assays have been performed during the last few decades years for hydroxyapatite bioactive coatings, there is a lack of exploitation of real-time in vitro interaction measurements. In the present work, real-time interactions for a plasma sprayed hydroxyapatite coating were measured by a Multi-Parametric Surface Plasmon Resonance (MP-SPR), and the results were compared with standard traditional cell viability in vitro assays. MP-SPR is proven to be suitable not only for measurement of molecule-molecule interactions but also molecule-material interaction measurements and cell interaction. Although SPR is extensively utilized in interaction studies, recent research of protein or cell adsorption on hydroxyapatite coatings for prostheses applications was not found. The as-sprayed hydroxyapatite coating resulted in 62.4% of crystalline phase and an average thickness of 24 ± 6 μm. The MP-SPR was used to measure lysozyme protein and human mesenchymal stem cells interaction to the hydroxyapatite coating. A comparison between the standard gold sensor and Hydroxyapatite (HA)-plasma coated sensor denoted a clearly favourable cell attachment on HA coated sensor as a significantly higher signal of cell binding was detected. Moreover, traditional cell viability and proliferation tests showed increased activity with culture time indicating that cells were proliferating on HA coating. Cells show homogeneous distribution and proliferation along the HA surface between one and seven days with no significant mortality. Cells were flattened and spread on rough surfaces from the first day, with increasing cytoplasmatic extensions during the culture time. PMID:27618911

  17. A real-time optical tracking and measurement processing system for flying targets.

    PubMed

    Guo, Pengyu; Ding, Shaowen; Zhang, Hongliang; Zhang, Xiaohu

    2014-01-01

    Optical tracking and measurement for flying targets is unlike the close range photography under a controllable observation environment, which brings extreme conditions like diverse target changes as a result of high maneuver ability and long cruising range. This paper first designed and realized a distributed image interpretation and measurement processing system to achieve resource centralized management, multisite simultaneous interpretation and adaptive estimation algorithm selection; then proposed a real-time interpretation method which contains automatic foreground detection, online target tracking, multiple features location, and human guidance. An experiment is carried out at performance and efficiency evaluation of the method by semisynthetic video. The system can be used in the field of aerospace tests like target analysis including dynamic parameter, transient states, and optical physics characteristics, with security control. PMID:24987748

  18. Real-time measurement of sub-PPM concentrations of airborne chemicals in semiconductor manufacturing.

    PubMed

    Corn, M; Cohen, R

    1993-01-01

    Real-time mass spectroscopy (ICAMS) can provide hourly or daily estimates of employee exposure. Field calibration of the unit indicated essentially linear response from 0.01 (Cellosolve Acetate) and 0.03 ppm (Diglyme) to 1 ppm in semiconductor cleanrooms. The instrument can be programmed for 4 minute readings on a single compound, or for rotation among several chemicals, each requiring 4 minute dwell times for analysis. In contrast to full shift personal sampling methods to measure exposure, ICAMS offers insights into the occurrence of peak exposures. In addition, in the occupational environment ICAMS results can be integrated to estimate full-shift within a zone exposures. Thus, the ICAMS extends measurement sensitivities below those currently available and offers a viable alternative to personal sampling in the semiconductor industry. PMID:9857292

  19. (abstract) Using GPS Measurements to Identify Global Ionospheric Storms in Near Real-Time

    NASA Technical Reports Server (NTRS)

    Ho, C. M.; Mannucci, A. J.; Lindqwister, U. J.; Rao, A. M.; Pi, X.; Wilson, B. D.; Yuan, D. N.; Reyes, M.

    1996-01-01

    The solar wind interacts with the Earth's magnetosphere, eventually dissipating energy into the ionosphere and atmosphere. As a terminator, the ionosphere responds to magnetic storms, which is very important in understanding the energy coupling process between the Sun and the Earth and in forecasting space weather changes.The worldwide GPS network, for the first time, makes near real-time global ionospheric TEC measurements a possibility. Based on these measurements, global ionospheric TEC maps are generated with time resolution of from 5 minutes to hours. Using these maps, we can analyze the global evolution of ionospheric storms on temporal and spatial scales, which have been dificult to study before. We find that for certain types of storms (such as TID-driven), it is possible to identify them near onset and issue warning signals during the early stages. Main attention has been paid on northern hemispheric winter storms. Their common features and physical mechanisms are being investigated.

  20. Real-time dielectric-film thickness measurement system for plasma processing chamber wall monitoring

    NASA Astrophysics Data System (ADS)

    Kim, Jin-Yong; Chung, Chin-Wook

    2015-12-01

    An in-situ real-time processing chamber wall monitoring system was developed. In order to measure the thickness of the dielectric film, two frequencies of small sinusoidal voltage (˜1 V) signals were applied to an electrically floated planar type probe, which is positioned at chamber wall surface, and the amplitudes of the currents and the phase differences between the voltage and current were measured. By using an equivalent sheath circuit model including a sheath capacitance, the dielectric thickness can be obtained. Experiments were performed in various plasma condition, and reliable dielectric film thickness was obtained regardless of the plasma properties. In addition, availability in commercial chamber for plasma enhanced chemical vapor deposition was verified. This study is expected to contribute to the control of etching and deposition processes and optimization of periodic maintenance in semiconductor manufacturing process.

  1. Performance modeling and measurement of real-time multiprocessors with time-shared buses

    SciTech Connect

    Woodbury, M.H.; Shin, K.G.

    1988-02-01

    A closed queueing network model is constructed to address workload effects on computer performance for a highly reliable unibus multiprocessor used in real-time control. The queueing model consists of multiserver nodes and a nonpreemptive priority queue. Use of this model requires partitioning the workload into task classes. The time average steady-state solution of the queuing model directly produces useful results that are necessary in performance evaluation. The model is experimentally justified with the Fault-Tolerant Multiprocessor (FTMP) located at the NASA AIRLAB. Extensive experiments are performed on FTMP with a synthetic workload generator (SWG) to directly measure performance parameters, such as processor idle time, system bus contention, and task processing times. These measurements determine values for parameters in the queueing model. Experimental and analytic results are then compared.

  2. Traffic dynamics: Method for estimating freeway travel times in real time from flow measurements

    SciTech Connect

    Nam, D.H.; Drew, D.R.

    1996-05-01

    This paper presents a method for estimating freeway travel times in real time directly from flow measurements, which is desirable for present and future Intelligent Vehicle-Highway Systems (IVHS) applications. An inductive modeling approach adapted here is based on stochastic queuing theory and the principle of conservation of vehicles. The analytical expression for link travel times satisfies traffic dynamics where the new form of the conservation of vehicles has been derived under generalized traffic conditions. A computer program has been developed to implement the algorithm. Analysis results show that the estimates have good agreement with empirical data measured at 30-s intervals. This methodology has potential applicable to automatic traffic control and automatic incident detection.

  3. A Real-Time Optical Tracking and Measurement Processing System for Flying Targets

    PubMed Central

    Guo, Pengyu; Ding, Shaowen; Zhang, Hongliang; Zhang, Xiaohu

    2014-01-01

    Optical tracking and measurement for flying targets is unlike the close range photography under a controllable observation environment, which brings extreme conditions like diverse target changes as a result of high maneuver ability and long cruising range. This paper first designed and realized a distributed image interpretation and measurement processing system to achieve resource centralized management, multisite simultaneous interpretation and adaptive estimation algorithm selection; then proposed a real-time interpretation method which contains automatic foreground detection, online target tracking, multiple features location, and human guidance. An experiment is carried out at performance and efficiency evaluation of the method by semisynthetic video. The system can be used in the field of aerospace tests like target analysis including dynamic parameter, transient states, and optical physics characteristics, with security control. PMID:24987748

  4. High-resolution micromechanical measurement in real time of forces exerted by living cells

    PubMed Central

    Swierczewski, Robert; Hedley, John; Redfern, Chris P. F.

    2016-01-01

    ABSTRACT The aim of this study was to compare uniaxial traction forces exerted by different cell types using a novel sensor design and to test the dependence of measured forces on cytoskeletal integrity. The sensor design detects forces generated between 2 contact points by cells spanning a gap. The magnitude of these forces varied according to cell type and were dependent on cytoskeletal integrity. The response time for drug-induced cytoskeletal disruption also varied between cell types: dermal fibroblasts exerted the greatest forces and had the slowest drug response times; EBV-transformed epithelial cells also had slow cytoskeletal depolymerisation times but exerted the lowest forces overall. Conversely, lung epithelial tumor cells exerted low forces but had the fastest depolymerisation drug response. These results provide proof of principle for a new design of force-measurement sensor based on optical interferometry, an approach that can be used to study cytoskeletal dynamics in real time. PMID:26645140

  5. Real-Time Discrimination and Versatile Profiling of Spontaneous Reactive Oxygen Species in Living Organisms with a Single Fluorescent Probe.

    PubMed

    Zhang, Ruilong; Zhao, Jun; Han, Guangmei; Liu, Zhengjie; Liu, Cui; Zhang, Cheng; Liu, Bianhua; Jiang, Changlong; Liu, Renyong; Zhao, Tingting; Han, Ming-Yong; Zhang, Zhongping

    2016-03-23

    Fluorescent probes are powerful tools for the investigations of reactive oxygen species (ROS) in living organisms by visualization and imaging. However, the multiparallel assays of several ROS with multiple probes are often limited by the available number of spectrally nonoverlapping chromophores together with large invasive effects and discrepant biological locations. Meanwhile, the spontaneous ROS profilings in various living organs/tissues are also limited by the penetration capability of probes across different biological barriers and the stability in reactive in vivo environments. Here, we report a single fluorescent probe to achieve the effective discrimination and profiling of hydroxyl radicals (•OH) and hypochlorous acid (HClO) in living organisms. The probe is constructed by chemically grafting an additional five-membered heterocyclic ring and a lateral triethylene glycol chain to a fluorescein mother, which does not only turn off the fluorescence of fluorescein, but also create the dual reactive sites to ROS and the penetration capability in passing through various biological barriers. The reactions of probe with •OH and HClO simultaneously result in cyan and green emissions, respectively, providing the real-time discrimination and quantitative analysis of the two ROS in cellular mitochondria. Surprisingly, the accumulation of probes in the intestine and liver of a normal-state zebrafish and the transfer pathway from intestine-to-blood-to-organ/tissue-to-kidney-to-excretion clearly present the profiling of spontaneous •OH and HClO in these metabolic organs. In particular, the stress generation of •OH at the fresh wound of zebrafish is successfully visualized for the first time, in spite of its extremely short lifetime. PMID:26938117

  6. Self-referencing luminescent optrodes for non-invasive, real time measurement of extracellular flux

    NASA Astrophysics Data System (ADS)

    McLamore, Eric S.; Porterfield, D. Marshall; Borgens, R. B.; Banks, M. K.

    2011-05-01

    Autonomous technologies are needed which are capable of sensing real time changes in biophysical transport across cell membranes/organelles. These technologies must not only be highly sensitive/selective, but must also be minimally invasive/intrusive, causing no significant physical/chemical effects on cell behavior. Challenges with mainstream technologies (e.g., assays, fluorescent dyes, microsensors) include signal noise/drift, low temporal resolution, requirement of large sample sizes, cytoxicity, organelle sequestration, and intracellular buffering. Recent advancements in fiber optics have greatly enhanced the performance of microsensors (e.g., increased sensitivity/selectivity, response time), but used in concentration mode near cells/tissues these sensors suffer from poor signal to noise ratio. Work over the last few decades has advanced microsensor utility through sensing modalities that extend and enhance the data recorded by sensors. This technique, known as self-referencing, converts static micro/nanosensors with otherwise low signal-to-noise ratios into dynamic flux sensors capable of filtering out signals not associated with active transport by acquisition and amplification of differential signals. Here, we demonstrate the use of a self-referencing referencing frequency domain fiber optic microsensor containing a quenched dye (platinum tetrakis-pentafluorophenyl porphyrin) for quantifying cell/tissue flux in biomedical, agricultural, and environmental applications.

  7. Real-time HF Radio Absorption Maps Incorporating Riometer and Satellite Measurements

    NASA Astrophysics Data System (ADS)

    Rogers, Neil; Honary, Farideh; Warrington, Mike; Stocker, Alan; Danskin, Donald

    2016-04-01

    A real-time model of HF radio propagation conditions is being developed as a service for aircraft communications at high latitudes. An essential component of this is a real-time map of the absorption of HF (3-30 MHz) radio signals in the D-region ionosphere. Empirical, climatological Polar Cap Absorption (PCA) models in common usage cannot account for day-to-day variations in ionospheric composition and are inaccurate during the large changes in recombination rate at twilight. However, parameters of such models may be optimised using an age-weighted regression to absorption measurements from riometers in Canada and Scandinavia. Such parameters include the day- and night-time sensitivity to proton flux as measured on a geostationary satellite (GOES). Modelling the twilight transition as a linear or Gauss error function over a range of solar-zenith angles (χl < χ < χu) is found to provide greater accuracy than 'Earth shadow' methods (as applied in the Sodankylä Ionospheric Chemistry (SIC) model, for example) due to a more gradual ionospheric response for χ < 90° . The fitted χl parameter is found to be most variable, with smaller values (as low as 60°) post-sunrise compared with pre-sunset. Correlation coefficients of model parameters between riometers are presented and these provide a means of appropriately weighting individual riometer contributions in an assimilative PCA model. At times outside of PCA events, the probability of absorption in the auroral zones is related to the energetic electron flux inside the precipitation loss cone, as measured on the polar-orbiting POES satellites. This varies with magnetic local time, magnetic latitude and geomagnetic activity, and its relation to the real-time solar wind - magnetospheric coupling function [Newell et al., 2007] will be presented. Reference: Newell, P. T., T. Sotirelis, K. Liou, C.-I. Meng, and F. J. Rich (2007), A nearly universal solar wind-magnetosphere coupling function inferred from 10

  8. Measuring Sea-Ice Motion in the Arctic with Real Time Photogrammetry

    NASA Astrophysics Data System (ADS)

    Brozena, J. M.; Hagen, R. A.; Peters, M. F.; Liang, R.; Ball, D.

    2014-12-01

    The U.S. Naval Research Laboratory, in coordination with other groups, has been collecting sea-ice data in the Arctic off the north coast of Alaska with an airborne system employing a radar altimeter, LiDAR and a photogrammetric camera in an effort to obtain wide swaths of measurements coincident with Cryosat-2 footprints. Because the satellite tracks traverse areas of moving pack ice, precise real-time estimates of the ice motion are needed to fly a survey grid that will yield complete data coverage. This requirement led us to develop a method to find the ice motion from the aircraft during the survey. With the advent of real-time orthographic photogrammetric systems, we developed a system that measures the sea ice motion in-flight, and also permits post-process modeling of sea ice velocities to correct the positioning of radar and LiDAR data. For the 2013 and 2014 field seasons, we used this Real Time Ice Motion Estimation (RTIME) system to determine ice motion using Applanix's Inflight Ortho software with an Applanix DSS439 system. Operationally, a series of photos were taken in the survey area. The aircraft then turned around and took more photos along the same line several minutes later. Orthophotos were generated within minutes of collection and evaluated by custom software to find photo footprints and potential overlap. Overlapping photos were passed to the correlation software, which selects a series of "chips" in the first photo and looks for the best matches in the second photo. The correlation results are then passed to a density-based clustering algorithm to determine the offset of the photo pair. To investigate any systematic errors in the photogrammetry, we flew several flight lines over a fixed point on various headings, over an area of non-moving ice in 2013. The orthophotos were run through the correlation software to find any residual offsets, and run through additional software to measure chip positions and offsets relative to the aircraft

  9. Endothelial cell adhesion in real time. Measurements in vitro by tandem scanning confocal image analysis.

    PubMed

    Davies, P F; Robotewskyj, A; Griem, M L

    1993-06-01

    Real time measurements of cell-substratum adhesion in endothelial cells were obtained by tandem scanning confocal microscopy of sites of focal contact (focal adhesions) at the abluminal cell surface. Focal contact sites were sharply defined (low radiance levels) in the living cell such that the images could be enhanced, digitized, and isolated from other cellular detail. Sites of focal contact are the principal determinant of cell-substratum adhesion. Measurements of (a) the focal contact area and (b) the closeness of contact (inverse radiance) were used to nominally define the adhesion of a single cell or field of cells, and to record spontaneous and induced changes of cell adhesion in real time. The topography of focal contacts was estimated by calculating separation distances from radiance values using a calibration technique based on interference ring optics. While slightly closer contact was noted between the cell membrane and substratum at or near the center of each focal contact, separation distances throughout the adhesion regions were always < 50 nm. Subtraction of consecutive images revealed continuous spontaneous remodeling of individual focal adhesions in unperturbed cells during periods of < 1 min. Despite extensive remodeling of focal contact sites, however, cell adhesion calculated for an entire cell over extended periods varied by < 10%. When cytoskeletal stability was impaired by exposure to cytochalasin or when cells were exposed to proteolytic enzyme, endothelial adhesion declined rapidly. Such changes were recorded at the level of single cells, groups of cells, and at single focal adhesions. In both unperturbed and manipulated cells, the dynamics of remodeling and cell adhesion characteristics varied greatly between individual sites within the same cell; disappearance of existing sites and appearance of new ones often occurred within minutes while adjacent sites underwent minimal remodelling. Tandem scanning confocal microscopy image analysis of

  10. Real-time reflectometry measurement validation in H-mode regimes for plasma position control.

    PubMed

    Santos, J; Guimarais, L; Manso, M

    2010-10-01

    It has been shown that in H-mode regimes, reflectometry electron density profiles and an estimate for the density at the separatrix can be jointly used to track the separatrix within the precision required for plasma position control on ITER. We present a method to automatically remove, from the position estimation procedure, measurements performed during collapse and recovery phases of edge localized modes (ELMs). Based on the rejection mechanism, the method also produces an estimate confidence value to be fed to the position feedback controller. Preliminary results show that the method improves the real-time experimental separatrix tracking capabilities and has the potential to eliminate the need for an external online source of ELM event signaling during control feedback operation. PMID:21061481