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Sample records for fluorescence yield measured

  1. Energy Dependence of Air Fluorescence Yield measured by AIRFLY

    CERN Document Server

    Ave, M

    2007-01-01

    In the fluorescence detection of ultra high energy (> 10**18 eV) cosmic rays, the number of emitted fluorescence photons is assumed to be proportional to the energy deposited in air by shower particles. We have performed measurements of the fluorescence yield in atmospheric gases excited by electrons over energies ranging from keV to hundreds of MeV in several accelerators. We found that within the measured energy ranges the proportionality holds at the level of few %.

  2. Measurements of the Fluorescence Light Yield in Electromagnetic Showers

    Science.gov (United States)

    Reil, K.; Chen, P.; Field, C.; Hast, C.; Iverson, R.; Ng, J. S. T.; Odian, A.; Vincke, H.; Walz, D.; Belz, J.; Goldammer, A.; Guest, D.; Bergman, D. R.; Cavanaugh, S.; Perera, L.; Schnetzer, S.; Thomson, G. B.; Zech, A.; Cao, Z.; Huentemeyer, P.; Jui, C. C. H.; Loh, E. C.; Martens, K.; Matthews, J. N.; Smith, J. D.; Sokolsky, P.; Springer, R. W.; Thomas, S. B.; Chang, F. Y.; Chen, C. C.; Chen, C. W.; Huang, M. A.; Hwang, W.-Y. P.; Lin, G.-L.

    The two most common methods of determining the energy of an ultra high energy cosmic ray (UHECR) are ground arrays and fluorescence telescopes. Ground array detectors determine energy by sampling the number of shower particles arriving at the surface of the earth. In general, the more particles, the higher the energy. Fluorescence telescopes, on the other hand, determine the energy by measuring the number of ultraviolet photons produced by the electromagnetic shower produced in the atmosphere. The number of photons is related to the number of particles in the shower by the fluorescence yield (measured in photons per meter per charged particle). The Akeno Giant Air Shower Array (AGASA) and the High Resolution Flys Eye (HiRes) are the current world leading ground array and fluorescence detectors, respectively. Recent results from the two experiments indicate a significant discrepancy in the flux of cosmic rays as a function of energy[1―3 ]. This indicates that there may be a systematic offset in energy determination in the two techniques. The FLuorescence in Air from SHowers (FLASH) experiment is an effort to reduce the systematic uncertainty in energy determination for fluorescence detectors by making an improved measurement of the fluorescence yield. This work is intended to add to the prior work of Bunner, Kakimoto et al. and Nagano et al.[4―7]. We report on the current status of the experiment.

  3. Comparison of available measurements of the absolute fluorescence yield

    CERN Document Server

    Rosado, J; Arqueros, F

    2010-01-01

    The uncertainty in the absolute value of the fluorescence yield is still one of the main contributions to the total error in the reconstruction of the primary energy of ultra-energetic air showers using the fluorescence technique. A significant number of experimental values of the fluorescence yield have been published in the last years, however reported results are given very often in different units (photons/MeV or photons/m) and for different wavelength intervals. In this work we present a comparison of available results normalized to its value in photons/MeV for the 337 nm band at 800 hPa and 293 K. Possible sources of systematic errors on these measurements are discussed. In particular, the conversion of photons/m to photons/MeV requires an accurate determination of the energy deposited by the electrons in the field of view of the experimental setup. We have calculated the energy deposition for each experiment by means of a detailed Monte Carlo simulation including when possible the geometrical details o...

  4. Fluorescence quantum yield measurements of fluorescent proteins: a laboratory experiment for a biochemistry or molecular biophysics laboratory course.

    Science.gov (United States)

    Wall, Kathryn P; Dillon, Rebecca; Knowles, Michelle K

    2015-01-01

    Fluorescent proteins are commonly used in cell biology to assess where proteins are within a cell as a function of time and provide insight into intracellular protein function. However, the usefulness of a fluorescent protein depends directly on the quantum yield. The quantum yield relates the efficiency at which a fluorescent molecule converts absorbed photons into emitted photons and it is necessary to know for assessing what fluorescent protein is the most appropriate for a particular application. In this work, we have designed an upper-level, biochemistry laboratory experiment where students measure the fluorescence quantum yields of fluorescent proteins relative to a standard organic dye. Four fluorescent protein variants, enhanced cyan fluorescent protein (ECFP), enhanced green fluorescent protein (EGFP), mCitrine, and mCherry, were used, however the methods described are useful for the characterization of any fluorescent protein or could be expanded to fluorescent quantum yield measurements of organic dye molecules. The laboratory is designed as a guided inquiry project and takes two, 4 hr laboratory periods. During the first day students design the experiment by selecting the excitation wavelength, choosing the standard, and determining the concentration needed for the quantum yield experiment that takes place in the second laboratory period. Overall, this laboratory provides students with a guided inquiry learning experience and introduces concepts of fluorescence biophysics into a biochemistry laboratory curriculum.

  5. A novel method for the absolute fluorescence yield measurement by AIRFLY

    CERN Document Server

    Ave, M

    2008-01-01

    One of the goals of the AIRFLY (AIR FLuorescence Yield) experiment is to measure the absolute fluorescence yield induced by electrons in air to better than 10% precision. We introduce a new technique for measurement of the absolute fluorescence yield of the 337 nm line that has the advantage of reducing the systematic uncertainty due to the detector calibration. The principle is to compare the measured fluorescence yield to a well known process - the Cerenkov emission. Preliminary measurements taken in the BFT (Beam Test Facility) in Frascati, Italy with 350 MeV electrons are presented. Beam tests in the Argonne Wakefield Accelerator at the Argonne National Laboratory, USA with 14 MeV electrons have also shown that this technique can be applied at lower energies.

  6. Precise measurement of the absolute fluorescence yield of the 337 nm band in atmospheric gases

    CERN Document Server

    Ave, M; Curry, E; Di Carlo, P; Di Giulio, C; Luis, P Facal San; Gonzales, D; Hojvat, C; Hörandel, J; Hrabovsky, M; Iarlori, M; Keilhauer, B; Klages, H; Kleifges, M; Kuehn, F; Li, S; Monasor, M; Nozka, L; Palatka, M; Petrera, S; Privitera, P; Ridky, J; Rizi, V; D'Orfeuil, B Rouille; Salamida, F; Schovanek, P; Smida, R; Spinka, H; Ulrich, A; Verzi, V; Williams, C

    2012-01-01

    A measurement of the absolute fluorescence yield of the 337 nm nitrogen band, relevant to ultra-high energy cosmic ray (UHECR) detectors, is reported. Two independent calibrations of the fluorescence emission induced by a 120 GeV proton beam were employed: Cherenkov light from the beam particle and calibrated light from a nitrogen laser. The fluorescence yield in air at a pressure of 1013 hPa and temperature of 293 K was found to be $Y_{337} = 5.61\\pm 0.06_{stat} \\pm 0.21_{syst}$ photons/MeV. When compared to the fluorescence yield currently used by UHECR experiments, this measurement improves the uncertainty by a factor of three, and has a significant impact on the determination of the energy scale of the cosmic ray spectrum.

  7. Absolute measurement of the nitrogen fluorescence yield in air between 300 and 430 nm

    CERN Document Server

    Lefeuvre, G; Gorodetzky, P; Patzak, T; Salin, P

    2007-01-01

    The nitrogen fluorescence induced in air is used to detect ultra-high energy cosmic rays and to measure their energy. The precise knowledge of the absolute fluorescence yield is the key quantity to improve the accuracy on the cosmic ray energy. The total yield has been measured in dry air using a 90Sr source and a [300-430 nm] filter. The fluorescence yield in air is 4.23 $\\pm$ 0.20 photons per meter when normalized to 760 mmHg, 15 degrees C and with an electron energy of 0.85 MeV. This result is consistent with previous experiments made at various energies, but with an accuracy improved by a factor of about 3. For the first time, the absolute continuous spectrum of nitrogen excited by 90Sr electrons has also been measured with a spectrometer. Details of this experiment are given in one of the author's PhD thesis [32].

  8. Fluorescence Quantum Yield Measurements of Fluorescent Proteins: A Laboratory Experiment for a Biochemistry or Molecular Biophysics Laboratory Course

    Science.gov (United States)

    Wall, Kathryn P.; Dillon, Rebecca; Knowles, Michelle K.

    2015-01-01

    Fluorescent proteins are commonly used in cell biology to assess where proteins are within a cell as a function of time and provide insight into intracellular protein function. However, the usefulness of a fluorescent protein depends directly on the quantum yield. The quantum yield relates the efficiency at which a fluorescent molecule converts…

  9. O2(1△) Yield Measurement by Raman Spectroscopy With Elimination of Chlorine Fluorescence Interference

    Institute of Scientific and Technical Information of China (English)

    Rong-rong Cui; Wen-bo Shi; Lie-zheng Deng; He-ping Yang; Guo-he Sha; Cun-hao Zhang

    2012-01-01

    Deleterious chlorine fluorescence was found to occur at the same frequency as the Raman scattering of O2(1△) and O2(3∑),seriously affecting the O2(1△) yield measurement in the reaction of chlorine with basic hydrogen peroxide by use of the Raman spectroscopy technique.To solve this problem we have taken advantage of the fact that Raman radiation is always strongly polarized while fluorescence is essentially non-polarized in a gaseous medium.When chlorine utilization of a singlet oxygen generator is 88%,O2(1△) yield reaches (42.4±7.4)%with the effect of chlorine fluorescence completely eliminated.

  10. Measurement of air and nitrogen fluorescence light yields induced by electron beam for UHECR experiments

    CERN Document Server

    Colin, P; Grebenyuk, V; Naumov, D; Nédélec, P; Nefedov, Y; Onofre, A; Porokhovoi, S; Sabirov, B; Tkatchev, L G

    2006-01-01

    Most of the Ultra High Energy Cosmic Ray (UHECR) experiments and projects (HiRes, AUGER, TA, EUSO, TUS,...) use air fluorescence to detect and measure extensive air showers (EAS). The precise knowledge of the Fluorescence Light Yield (FLY) is of paramount importance for the reconstruction of UHECR. The MACFLY - Measurement of Air Cherenkov and Fluorescence Light Yield - experiment has been designed to perform such FLY measurements. In this paper we will present the results of FLY in the 290-440 nm wavelength range for dry air and pure nitrogen, both excited by electrons with energy of 1.5 MeV, 20 GeV and 50 GeV. The experiment uses a 90Sr radioactive source for low energy measurement and a CERN SPS electron beam for high energy. We find that the FLY is proportional to the deposited energy (E_d) in the gas and we show that the air fluorescence properties remain constant independently of the electron energy. At the reference point: atmospheric dry air at 1013 hPa and 23C, the ratio FLY/E_d=17.6 photon/MeV with ...

  11. Average value of available measurements of the absolute air-fluorescence yield

    CERN Document Server

    Rosado, J; Arqueros, F

    2011-01-01

    The air-fluorescence yield is a key parameter for determining the energy scale of ultra-high-energy cosmic rays detected by fluorescence telescopes. A compilation of the available measurements of the absolute air-fluorescence yield normalized to its value in photons per MeV for the 337 nm band at given pressure and temperature has been recently presented in Ref. [1]. Also, in that paper, some corrections in the evaluation of the energy deposited in the corresponding experimental collision chambers have been proposed. In this note this comparison is updated. In addition, a simple statistical analysis is carried out showing that our corrections favor the compatibility among the various experiments. As a result, an average value of 5.45 ph/MeV for the fluorescence yield of the 337 nm band (20.1 ph/MeV for the spectral interval 300-420 nm) at 1013 hPa and 293 K with an uncertainty of 5% is found. This result is fully compatible with that recently presented by the AIRFLY collaboration (still preliminary) in such a...

  12. Precise Measurement of the Absolute Yield of Fluorescence Photons in Atmospheric Gases

    CERN Document Server

    Ave, M; Daumiller, K; Di Carlo, P; Di Giulio, C; Luis, P Facal San; Gonzales, D; Hojvat, C; Hörandel, J R; Hrabovský, M; Iarlori, M; Keilhauer, B; Klages, H; Kleifges, M; Kuehn, F; Monasor, M; Nožka, L; Palatka, M; Petrera, S; Privitera, P; Ridky, J; Rizi, V; d'Orfeuil, B Rouillé; Salamida, F; Schovánek, P; Šmida, R; Spinka, H; Ulrich, A; Verzi, V; Williams, C

    2011-01-01

    We have performed a measurement of the absolute yield of fluorescence photons at the Fermilab Test Beam. A systematic uncertainty at 5% level was achieved by the use of Cherenkov radiation as a reference calibration light source. A cross-check was performed by an independent calibration using a laser light source. A significant improvement on the energy scale uncertainty of Ultra-High Energy Cosmic Rays is expected.

  13. Precise measurement of the absolute yield of fluorescence photons in atmospheric gases

    Energy Technology Data Exchange (ETDEWEB)

    Ave, M. [Karlsruhe Institute of Technology, IK, Postfach 6980, D - 76021 Karlsruhe (Germany); Bohacova, M. [University of Chicago, Enrico Fermi Institute and Kavli Institute for Cosmological Physics, 5640 S. Ellis Ave., Chicago, IL 60637 (United States); Institute of Physics of the Academy of Sciences of the Czech Republic, Na Slovance 2, CZ-182 21 Praha 8 (Czech Republic); Daumiller, K. [Karlsruhe Institute of Technology, IK, Postfach 6980, D - 76021 Karlsruhe (Germany); Di Carlo, P. [Dipartimento di Fisica dell' Universita de l' Aquila and INFN, Via Vetoio, I-67010 Coppito, Aquila (Italy); Di Giulio, C. [Dipartimento di Fisica dell' Universita di Roma Tor Vergata and Sezione INFN, Via della Ricerca Scientifica, I-00133 Roma (Italy); Facal San Luis, Pedro, E-mail: facal@kicp.uchicago.edu [University of Chicago, Enrico Fermi Institute and Kavli Institute for Cosmological Physics, 5640 S. Ellis Ave., Chicago, IL 60637 (United States); Gonzales, D. [Karlsruhe Institute of Technology, IEKP, Postfach 3640, D - 76021 Karlsruhe (Germany); Hojvat, C. [Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States); Hoerandel, J.R. [IMAPP, Radboud University Nijmegen, 6500 GL Nijmegen (Netherlands); Hrabovsky, M. [Palacky University, RCATM, Olomuc (Czech Republic); Iarlori, M. [Dipartimento di Fisica dell' Universita de l' Aquila and INFN, Via Vetoio, I-67010 Coppito, Aquila (Italy); Keilhauer, B.; Klages, H. [Karlsruhe Institute of Technology, IK, Postfach 6980, D - 76021 Karlsruhe (Germany); Kleifges, M. [Karlsruhe Institute of Technology, IPE, Postfach 3640, D - 76021 Karlsruhe (Germany); Kuehn, F. [Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States); Monasor, M. [University of Chicago, Enrico Fermi Institute and Kavli Institute for Cosmological Physics, 5640 S. Ellis Ave., Chicago, IL 60637 (United States); Nozka, L.; Palatka, M. [Institute of Physics of the Academy of Sciences of the Czech Republic, Na Slovance 2, CZ-182 21 Praha 8 (Czech Republic)

    2011-03-15

    We have performed a measurement of the absolute yield of fluorescence photons at the Fermilab Test Beam. A systematic uncertainty at 5% level was achieved by the use of Cherenkov radiation as a reference calibration light source. A cross-check was performed by an independent calibration using a laser light source. A significant improvement on the energy scale uncertainty of Ultra-High Energy Cosmic Rays is expected.

  14. Measurement of vacancy transfer probability from K to L shell using K-shell fluorescence yields

    Indian Academy of Sciences (India)

    Ö Söğüt; E Büyükkasap; A Küçükönder; T Tarakçioğlu

    2009-10-01

    The vacancy transfer probabilities from K to L shell through radiative decay, KL , have been deduced for the elements in the range 19 ≤ ≤ 58 using K-shell fluorescence yields. The targets were irradiated with photons at 59.5 keV from a 75mCi 241Am annular source. The K X-rays from different targets were detected with a high resolution Si(Li) detector. The measurement of vacancy transfer probabilities are least-squared fitted to second-order polynomials to obtain analytical relations that represent these probabilities as a function of atomic number. The obtained results agree with theoretical and fitted values.

  15. Temperature and Humidity Dependence of Air Fluorescence Yield measured by AIRFLY

    CERN Document Server

    Ave, M; Bohacova, M; Buonomo, B; Busca, N; Cazon, L; Chemerisov, S D; Conde, M E; Crowell, R A; Di Carlo, P; Di Giulio, C; Doubrava, M; Esposito, A; Facal, P; Franchini, F J; Horandel, J; Hrabovsky, M; Iarlori, M; Kasprzyk, T E; Keilhauer, B; Klages, H; Kleifges, M; Kuhlmann, S; Mazzitelli, G; Nozka, L; Obermeier, A; Palatka, M; Petrera, S; Privitera, P; Rídky, J; Rizi, V; Rodríguez, G; Salamida, F; Schovanek, P; Spinka, H; Strazzeri, E; Ulrich, A; Yusof, Z M; Vacek, V; Valente, P; Verzi, V; Waldenmaier, T

    2007-01-01

    The fluorescence detection of ultra high energy cosmic rays requires a detailed knowledge of the fluorescence light emission from nitrogen molecules over a wide range of atmospheric parameters, corresponding to altitudes typical of the cosmic ray shower development in the atmosphere. We have studied the temperature and humidity dependence of the fluorescence light spectrum excited by MeV electrons in air. Results for the 313.6 nm, 337.1 nm, 353.7 nm and 391.4 nm bands are reported in this paper. We found that the temperature and humidity dependence of the quenching process changes the fluorescence yield by a sizeable amount (up to 20%) and its effect must be included for a precise estimation of the energy of ultra high energy cosmic rays.

  16. A Proposed Method for Measurement of Absolute Air Fluorescence Yield based on High Resolution Optical Emission Spectroscopy

    CERN Document Server

    Gika, V; Maltezos, S

    2016-01-01

    In this work, we present a method for absolute measurement of air fluorescence yield based on high resolution optical emission spectroscopy. The absolute measurement of the air fluorescence yield is feasible using the Cherenkov light, emitted by an electron beam simultaneously with the fluorescence light, as a "standard candle". The separation of these two radiations can be accomplished exploiting the "dark" spectral regions of the emission band systems of the molecular spectrum of nitrogen. In these "dark" regions the net Cherenkov light can be recorded experimentally and be compared with the calculated one. The instrumentation for obtaining the nitrogen molecular spectra in high resolution and the noninvasive method for monitoring the rotational temperature of the emission process are also described. For the experimental evaluation of the molecular spectra analysis we used DC normal glow discharges in air performed in an appropriate spectral lamp considered as an air-fluorescence light emulator. The propose...

  17. Comparison of available measurements of the absolute air-fluorescence yield and determination of its global average value

    CERN Document Server

    Rosado, J; Arqueros, F

    2011-01-01

    Experimental results of the absolute air-fluorescence yield are given very often in different units (photons/MeV or photons/m) and for different wavelength intervals. In this work we present a comparison of available results normalized to its value in photons/MeV for the 337 nm band at 1013 hPa and 293 K. The conversion of photons/m to photons/MeV requires an accurate determination of the energy deposited by the electrons in the field of view of the experimental set-up. We have calculated the energy deposition for each experiment by means of a detailed Monte Carlo simulation and the results have been compared with those assumed or calculated by the authors. As a result, corrections to the reported fluorescence yields are proposed. These corrections improve the compatibility between measurements in such a way that a reliable average value with uncertainty at the level of 5% is obtained.

  18. Effects of Bleaching by Nitrogen Deficiency on the Quantum Yield of Photosystem II in Synechocystis sp. PCC 6803 Revealed by Chl Fluorescence Measurements.

    Science.gov (United States)

    Ogawa, Takako; Sonoike, Kintake

    2016-03-01

    Estimation of photosynthesis by Chl fluorescence measurement of cyanobacteria is always problematic due to the interference from respiratory electron transfer and from phycocyanin fluorescence. The interference from respiratory electron transfer could be avoided by the use of DCMU or background illumination by blue light, which oxidizes the plastoquinone pool that tends to be reduced by respiration. On the other hand, the precise estimation of photosynthesis in cells with a different phycobilisome content by Chl fluorescence measurement is difficult. By subtracting the basal fluorescence due to the phycobilisome and PSI, it becomes possible to estimate the precise maximum quantum yield of PSII in cyanobacteria. Estimated basal fluorescence accounted for 60% of the minimum fluorescence, resulting in a large difference between the 'apparent' yield and 'true' yield under high phycocyanin conditions. The calculated value of the 'true' maximum quantum yield of PSII was around 0.8, which was similar to the value observed in land plants. The results suggest that the cause of the apparent low yield reported in cyanobacteria is mainly ascribed to the interference from phycocyanin fluorescence. We also found that the 'true' maximum quantum yield of PSII decreased under nitrogen-deficient conditions, suggesting the impairment of the PSII reaction center, while the 'apparent' maximum quantum yield showed a marginal change under the same conditions. Due to the high contribution of phycocyanin fluorescence in cyanobacteria, it is essential to eliminate the influence of the change in phycocyanin content on Chl fluorescence measurement and to evaluate the 'true' photosynthetic condition.

  19. Estimating chlorophyll content and photochemical yield of photosystem II (ΦPSII) using solar-induced chlorophyll fluorescence measurements at different growing stages of attached leaves.

    Science.gov (United States)

    Tubuxin, Bayaer; Rahimzadeh-Bajgiran, Parinaz; Ginnan, Yusaku; Hosoi, Fumiki; Omasa, Kenji

    2015-09-01

    This paper illustrates the possibility of measuring chlorophyll (Chl) content and Chl fluorescence parameters by the solar-induced Chl fluorescence (SIF) method using the Fraunhofer line depth (FLD) principle, and compares the results with the standard measurement methods. A high-spectral resolution HR2000+ and an ordinary USB4000 spectrometer were used to measure leaf reflectance under solar and artificial light, respectively, to estimate Chl fluorescence. Using leaves of Capsicum annuum cv. 'Sven' (paprika), the relationships between the Chl content and the steady-state Chl fluorescence near oxygen absorption bands of O2B (686nm) and O2A (760nm), measured under artificial and solar light at different growing stages of leaves, were evaluated. The Chl fluorescence yields of ΦF 686nm/ΦF 760nm ratios obtained from both methods correlated well with the Chl content (steady-state solar light: R(2) = 0.73; artificial light: R(2) = 0.94). The SIF method was less accurate for Chl content estimation when Chl content was high. The steady-state solar-induced Chl fluorescence yield ratio correlated very well with the artificial-light-induced one (R(2) = 0.84). A new methodology is then presented to estimate photochemical yield of photosystem II (ΦPSII) from the SIF measurements, which was verified against the standard Chl fluorescence measurement method (pulse-amplitude modulated method). The high coefficient of determination (R(2) = 0.74) between the ΦPSII of the two methods shows that photosynthesis process parameters can be successfully estimated using the presented methodology.

  20. Measurement method for photoluminescent quantum yields of fluorescent organic dyes in polymethyl methacrylate for luminescent solar concentrators.

    Science.gov (United States)

    Wilson, L R; Richards, B S

    2009-01-10

    A method for measuring the photoluminescent quantum yields (PLQY) of luminescent organic dyes is presented. The self-absorption probability calculated at different dye concentrations is used to determine the absolute quantum yield from the observed values. The results for a range of commercially available dyes show high quantum yields, even at high concentrations, and an absence of quenching. The PLQY of several dye mixtures are also presented. The results indicate an absence of any reduction of PLQY in a dye mixture as compared with the individual PLQY of the dyes.

  1. On the absolute value of the air-fluorescence yield

    CERN Document Server

    Rosado, J; Arqueros, F

    2014-01-01

    The absolute value of the air-fluorescence yield is a key parameter for the energy reconstruction of extensive air showers registered by fluorescence telescopes. In previous publications, we reported a detailed Monte Carlo simulation of the air-fluorescence generation that allowed the theoretical evaluation of this parameter. This simulation has been upgraded in the present work. As a result, we determined an updated absolute value of the fluorescence yield of 7.9+-2.0 ph/MeV for the band at 337 nm in dry air at 800 hPa and 293 K, in agreement with experimental values. We have also performed a critical analysis of available absolute measurements of the fluorescence yield with the assistance of our simulation. Corrections have been applied to some measurements to account for a bias in the evaluation of the energy deposition. Possible effects of other experimental aspects have also been discussed. From this analysis, we determined an average fluorescence yield of 7.04+-0.24 ph/MeV at the above conditions.

  2. Measurement of K-X-rays fluorescence cross-sections, fluorescence yields and intensity ratios for elements in the atomic range 21 < Z < 74 excited by 59 keV photons

    Energy Technology Data Exchange (ETDEWEB)

    Gomez-Avila, J.; Lopez-Pino, N.; Padilla-Cabal, F.; Van Espen, P.; Cabal, A.; Pena, M. Ruiz; Alessandro, K.D.; Maidana, N.L. [Instituto Superior de Tecnologia y Ciencias Aplicadas (InSTEC), La Habana (Cuba); Antwerp Univ. (Belgium). Micro Trace Analytical Center; CEADEN, La Habana (Cuba); Universidade de Sao Paulo (IF/USP), SP (Brazil). Inst. de Fisica. Lab. do Acelerador Linear

    2010-07-01

    Full text: Using 59 keV photons, we measured the K{sub {alpha}}, K{sub {beta}} and total K X-rays fluorescence cross sections of 17 elements in the atomic range 21 < Z < 74. Furthermore, the fluorescence yields and the I{sub K{beta}} / I{sub K{alpha}} intensity ratios for these elements were also determined. An annular radioactive source of {sup 241}Am (activity 1 Ci) was employed to excite the elements in targets with the shape of foils or pellets (99% purity and 20 mm, in diameter). The pellets were formed with a mixture of cellulose and a chemical compound containing the element of interest, pressed at 15 tons. The K X-rays emitted from the irradiated samples were detected by a Si(Li) detector with a frontal Pb collimator, coupled to conventional electronics, with dead time below 10%. The fluxes reaching the targets and the crystal detector were determined by means of Monte Carlo (MC) simulations using the MCNPX V 2.6 code. The input geometries included the detector, the sample-source holder and the Pb collimator. The optimal diameter for the samples as well as the collimator dimensions were estimated by means of MC simulations. Using several elements (Ti, Ni, Br, Ag, Cs, Dy and W) a calibration curve for the effective flux of photons (I{sub 0}G{sub {epsilon}}) as function of the K X-rays energy was measured. Correction by different sizes and self-absorption coefficients of the samples were also performed. The data obtained for the X-rays fluorescence cross sections were compared with semi-empirical calculations and with experimental values reported by other authors; the relative deviations were less than 10%. Keywords: fluorescence cross section, fluorescence yields, Monte Carlo (author)

  3. The yield of air fluorescence induced by electrons

    CERN Document Server

    Arqueros, F; Castellanos, A; Ortiz, M; Rosado, J

    2006-01-01

    The fluorescence yield for dry air and pure nitrogen excited by electrons is calculated using a combination of well-established molecular properties and experimental data of the involved cross sections. Particular attention has been paid to the role of secondary electrons from ionization processes. At high pressure and high energy, observed fluorescence turns out to be proportional to the ionization cross section which follows the Born-Bethe law. Predictions on fluorescence yields in a very wide interval of electron energies (eV - GeV) and pressures (1 and 1013 hPa) as expected from laboratory measurements are presented. Experimental results at energies over 1 MeV are in very good agreement with our calculations for pure nitrogen while discrepancies of about 20% are found for dry air, very likely associated to uncertainties in the available data on quenching cross sections. The relationship between fluorescence emission, stopping power and deposited energy is discussed.

  4. PS II model based analysis of transient fluorescence yield measured on whole leaves of Arabidopsis thaliana after excitation with light flashes of different energies.

    Science.gov (United States)

    Belyaeva, N E; Schmitt, F-J; Paschenko, V Z; Riznichenko, G Yu; Rubin, A B; Renger, G

    2011-02-01

    Our recently presented PS II model (Belyaeva et al., 2008) was improved in order to permit a consistent simulation of Single Flash Induced Transient Fluorescence Yield (SFITFY) traces that were earlier measured by Steffen et al. (2005) on whole leaves of Arabidopsis (A.) thaliana at four different energies of the actinic flash. As the essential modification, the shape of the actinic flash was explicitly taken into account assuming that an exponentially decaying rate simulates the time dependent excitation of PS II by the 10 ns actinic flash. The maximum amplitude of this excitation exceeds that of the measuring light by 9 orders of magnitude. A very good fit of the SFITFY data was achieved in the time domain from 100 ns to 10s for all actinic flash energies (the maximum energy of 7.5 × 10¹⁶ photons/(cm²flash) is set to 100%, the relative energies of weaker actinic flashes were of ∼8%, 4%, ∼1%). Our model allows the calculation and visualization of the transient PS II redox state populations ranging from the dark adapted state, via excitation energy and electron transfer steps induced by pulse excitation, followed by final relaxation into the stationary state eventually attained under the measuring light. It turned out that the rate constants of electron transfer steps are invariant to intensity of the actinic laser flash. In marked contrast, an increase of the actinic flash energy by more than two orders of magnitude from 5.4×10¹⁴ photons/(cm²flash) to 7.5×10¹⁶ photons/(cm²flash), leads to an increase of the extent of fluorescence quenching due to carotenoid triplet (³Car) formation by a factor of 14 and of the recombination reaction between reduced primary pheophytin (Phe(-)) and P680(+) by a factor of 3 while the heat dissipation in the antenna complex remains virtually constant. The modified PS II model offers new opportunities to compare electron transfer and dissipative parameters for different species (e.g. for the green algae and the

  5. An optimised method for correcting quenched fluorescence yield

    Directory of Open Access Journals (Sweden)

    L. Biermann

    2014-05-01

    Full Text Available Under high light intensity, phytoplankton protect their photosystems from bleaching through non-photochemical quenching processes. The consequence of this is suppression of fluorescence emission, which must be corrected when measuring in situ yield with fluorometers. Previously, this has been done using the limit of the mixed layer, assuming that phytoplankton are uniformly mixed from the surface to this depth. However, the assumption of homogeneity is not robust in oceanic regimes that support deep chlorophyll maxima. To account for these features, we correct from the limit of the euphotic zone, defined as the depth at which light is at ~1% of the surface value. This method was applied to fluorescence data collected by eleven animal-borne fluorometers deployed in the Southern Ocean over four austral summers. Six tags returned data showing evidence of deep chlorophyll features. Using the depth of the euphotic layer, quenching was corrected without masking subsurface fluorescence signals.

  6. Fission yield measurements at IGISOL

    Directory of Open Access Journals (Sweden)

    Lantz M.

    2016-01-01

    Full Text Available The fission product yields are an important characteristic of the fission process. In fundamental physics, knowledge of the yield distributions is needed to better understand the fission process. For nuclear energy applications good knowledge of neutroninduced fission-product yields is important for the safe and efficient operation of nuclear power plants. With the Ion Guide Isotope Separator On-Line (IGISOL technique, products of nuclear reactions are stopped in a buffer gas and then extracted and separated by mass. Thanks to the high resolving power of the JYFLTRAP Penning trap, at University of Jyväskylä, fission products can be isobarically separated, making it possible to measure relative independent fission yields. In some cases it is even possible to resolve isomeric states from the ground state, permitting measurements of isomeric yield ratios. So far the reactions U(p,f and Th(p,f have been studied using the IGISOL-JYFLTRAP facility. Recently, a neutron converter target has been developed utilizing the Be(p,xn reaction. We here present the IGISOL-technique for fission yield measurements and some of the results from the measurements on proton induced fission. We also present the development of the neutron converter target, the characterization of the neutron field and the first tests with neutron-induced fission.

  7. Annual energy yield of the fluorescent solar concentrator

    Energy Technology Data Exchange (ETDEWEB)

    Van Sark, W.G.J.H.M.; Hellenbrand, G.F.M.G. [Department of Science, Technology and Society, Copernicus Institute for Sustainable Development and Innovation, Utrecht University, Heidelberglaan 2, 3584 CS Utrecht (Netherlands); Bende, E.E.; Burgers, A.R.; Slooff, L.H. [ECN Solar Energy, P.O. Box 1, 1755 ZG Petten (Netherlands)

    2008-09-15

    Fluorescent solar concentrators are but one candidate for lowering the costs of photovoltaic technology. State-of-the-art device conversion efficiencies are around 4%, and the device configuration can be optimized in terms of Euro per Watt. This paper aims to estimate the annual energy yield of such an optimized device configuration, using a detailed minutely spectral irradiance data set, describing a full year in the Netherlands, in combination with a ray-tracing model of the fluorescent solar concentrator. The spectral dataset is modeled using experimentally determined global, direct, and diffuse irradiation data on a minutely basis. Performance variations during the day for a number of typical days are investigated, i.e., for a clear summer day, a cloudy summer day, a clear winter day, and a cloudy winter day, using a ray-trace model of the fluorescent solar concentrator. Also, monthly aggregated spectra are used, as well as an annually aggregated spectrum to determine monthly and annual energy yields, respectively. As a result of a cost-per-unit-of-power optimization study, an optimum size of 23x23x0.1 cm{sup 3} was used, and an annual energy yield of 41.3 kWh/m{sup 2} could be estimated; this is 4.7 times lower than the annual energy yield of a state-of-the-art silicon solar cell.

  8. Precise measurement of the absolute fluorescence yield of nitrogen in air. Consequences on the detection of ultra-high energy cosmic rays; Mesure precise du rendement absolu de la fluorescence de l'azote dans l'air. Consequences sur la detection des rayons cosmiques d'ultra-haute energie

    Energy Technology Data Exchange (ETDEWEB)

    Lefeuvre, G

    2006-07-15

    The study of the energy spectrum of ultra-high energy cosmic rays (E > 10{sup 20} eV) requires to determine the energy with much more precision than what is currently achieved. The shower of particles created in the atmosphere can be detected either by sampling particle on the ground, or by detecting the fluorescence induced by the excitation of nitrogen by shower electrons. At present, the measurement of the fluorescence is the simplest and the most reliable method, since it does not call upon hadronic physics laws at extreme energies, a field still inaccessible to accelerators. The precise knowledge of the conversion factor between deposited energy and the number of fluorescence photons produced (the yield) is thus essential. Up to now, it has been determined with an accuracy of 15 % only. This main goal of this work is to measure this yield to better than 5 per cent. To do this, 1 MeV electrons from a radioactive source excite nitrogen of the air. The accuracy has been reached thanks to the implementation of a new method for the absolute calibration of the photomultipliers detecting the photons, to better than 2 per cent. The fluorescence yield, measured and normalized to 0.85 MeV, 760 mmHg and 15 Celsius degrees, is (4.23 {+-} 0.20) photons per meter, or (20.46 {+-} 0.98) photons per deposited MeV. In addition, and for the first time, the absolute fluorescence spectrum of nitrogen excited by a source has been measured with an optical grating spectrometer. (author)

  9. Sum rule distortions in fluorescence-yield x-ray magnetic circular dichroism

    Science.gov (United States)

    Liu, Boyang; Piamonteze, Cinthia; Delgado-Jaime, Mario Ulises; Wang, Ru-Pan; Heidler, Jakoba; Dreiser, Jan; Chopdekar, Rajesh; Nolting, Frithjof; de Groot, Frank M. F.

    2017-08-01

    The quantitative analysis of 3 d transition metal L2 ,3 edge x-ray magnetic circular dichroism (XMCD) spectra and the related sum rules are compared for measurements with electron yield and fluorescence yield detection. Multiplet calculations on divalent ions show that fluorescence yield detected sum rule derived expectation values of Lz and Sz show noticeable deviations and detection angle dependence. We show that small deviations of the polarization dependent fluorescent decay values lead to significant deviations in the Lz and Sz sum rule values. Fe and Co experimental XMCD spectra of a supported 10 nm CoFe2O4 thin film are measured simultaneously by both electron and fluorescence yield. The deviations shown in the experimental data are well explained by the calculations and are shown to mainly depend on the polarization dependent total decay. We conclude that fluorescence yield detected x-ray magnetic circular dichroism is unsuitable for quantitative analysis of the Lz and Sz sum rule values.

  10. Studying Photosynthesis by Measuring Fluorescence

    Science.gov (United States)

    Sanchez, Jose Francisco; Quiles, Maria Jose

    2006-01-01

    This paper describes an easy experiment to study the absorption and action spectrum of photosynthesis, as well as the inhibition by heat, high light intensity and the presence of the herbicide 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) on the photosynthetic process. The method involves measuring the chlorophyll fluorescence emitted by intact…

  11. Average M shell fluorescence yields for elements with 70≤Z≤92

    Energy Technology Data Exchange (ETDEWEB)

    Kahoul, A., E-mail: ka-abdelhalim@yahoo.fr [Department of Materials Science, Faculty of Sciences and Technology, Mohamed El Bachir El Ibrahimi University, Bordj-Bou-Arreridj 34030 (Algeria); LPMRN laboratory, Department of Materials Science, Faculty of Sciences and Technology, Mohamed El Bachir El Ibrahimi University, Bordj-Bou-Arreridj 34030 (Algeria); Deghfel, B. [Physics Department, Faculty of Sciences, M’Sila University, 28000 M’Sila (Algeria); Laboratory of materials physics and their applications, Physics Department, Faculty of Sciences, University of Mohamed Boudiaf, 28000 M’sila (Algeria); Aylikci, V. [Department of Metallurgical and Materials Engineering, Faculty of Technology, Mustafa Kemal University, Hatay 31040 (Turkey); Aylikci, N. K. [Department of Physics, Faculty of Sciences, Karadeniz Technical University, Trabzon 61080,Turkey (Turkey); Nekkab, M. [Physics Department, Faculty of Sciences, M’Sila University, 28000 M’Sila (Algeria); LESIMS laboratory, Faculty of Sciences, Ferhat Abbas University, Setif,19000 (Algeria)

    2015-03-30

    The theoretical, experimental and analytical methods for the calculation of average M-shell fluorescence yield (ω{sup ¯}{sub M}) of different elements are very important because of the large number of their applications in various areas of physical chemistry and medical research. In this paper, the bulk of the average M-shell fluorescence yield measurements reported in the literature, covering the period 1955 to 2005 are interpolated by using an analytical function to deduce the empirical average M-shell fluorescence yield in the atomic range of 70≤Z≤92. The results were compared with the theoretical and fitted values reported by other authors. Reasonable agreement was typically obtained between our result and other works.

  12. Size effects in the quantum yield of Cd Te quantum dots for optimum fluorescence bioimaging

    Energy Technology Data Exchange (ETDEWEB)

    Jacinto, C.; Rocha, U.S. [Universidade Federal de Alagoas (UFAL), Maceio, AL (Brazil). Inst. de Fisica. Grupo de Fotonica e Fluidos Complexos; Maestro, L.M.; Garcia-Sole, J.; Jaque, D. [Universidad Autonoma de Madrid (Spain). Dept. de Fisica de Materiales. Fluorescence Imaging Group

    2011-07-01

    those achievable when using CdSe-QDs. In this work, the size dependence of the fluorescence quantum yield of CdTe Quantum dots has been systematically investigated by Thermal Lens Spectroscopy. It has been found that optimum quantum yield is reached for 3.7 nm quantum dots. The presence of this optimum size has been corroborated by fluorescence experiments. Combination of quantum yield and fluorescence decay time measurements have concluded that the appearance of this optimum size emerges from the interplay between the frequency dependent radiative emission rate and the size dependent coupling strength between bulk exciton and surface trapping states. Our results open a new avenue in the search for new fluorescent 'multifunctional nanoprobes' for high resolution fluorescence imaging at the nanoscale. (author)

  13. Light propagation and fluorescence quantum yields in liquid scintillators

    Science.gov (United States)

    Buck, C.; Gramlich, B.; Wagner, S.

    2015-09-01

    For the simulation of the scintillation and Cherenkov light propagation in large liquid scintillator detectors a detailed knowledge about the absorption and emission spectra of the scintillator molecules is mandatory. Furthermore reemission probabilities and quantum yields of the scintillator components influence the light propagation inside the liquid. Absorption and emission properties are presented for liquid scintillators using 2,5-Diphenyloxazole (PPO) and 4-bis-(2-Methylstyryl)benzene (bis-MSB) as primary and secondary wavelength shifter. New measurements of the quantum yields for various aromatic molecules are shown.

  14. Light propagation and fluorescence quantum yields in liquid scintillators

    CERN Document Server

    Buck, C; Wagner, S

    2015-01-01

    For the simulation of the scintillation and Cherenkov light propagation in large liquid scintillator detectors a detailed knowledge about the absorption and emission spectra of the scintillator molecules is mandatory. Furthermore reemission probabilities and quantum yields of the scintillator components influence the light propagation inside the liquid. Absorption and emission properties are presented for liquid scintillators using 2,5-Diphenyloxazole (PPO) and 4-bis-(2-Methylstyryl)benzene (bis-MSB) as primary and secondary wavelength shifter. New measurements of the quantum yields for various aromatic molecules are shown.

  15. Experimental K-shell fluorescence yield of silicon

    Science.gov (United States)

    Campbell, J. L.; Cauchon, G.; Lakatos, T.; Lépy, M.-C.; McDonald, L.; Papp, T.; Plagnard, J.; Stemmler, P.; Teesdale, W. J.

    1998-11-01

    The K-shell fluorescence yield of silicon 0953-4075/31/21/009/img11 was determined by evaluating the escape-peak-to-parent-peak intensity ratio for monoenergetic x-rays in the energy range 2-9 keV and for manganese K x-rays from an 0953-4075/31/21/009/img12 radioactive source, using an Si(Li) detector. An order of magnitude improvement in low-energy tailing achieved during the last decade made possible a significant improvement relative to earlier Si(Li) experiments of this type. A detailed analysis of the spectra was performed, including the double-photoionization satellites of the escape peaks. Depending upon the choice of attenuation coefficient, the result of 0953-4075/31/21/009/img13 is 0.050 or 0.052, with approximately 0953-4075/31/21/009/img14 uncertainty in either case. This overall result is close to the semi-empirical fit values both of Krause and of Bambynek, but is significantly higher than the recent fitted values of Hubbell et al.

  16. Effect of PMMA impregnation on the fluorescence quantum yield of sol-gel glasses doped with quinine sulfate

    Science.gov (United States)

    Meneses-Nava, M. A.; Barbosa-García, O.; Díaz-Torres, L. A.; Chávez-Cerda, S.; Torres-Cisneros, M.; King, T. A.

    2001-08-01

    The fluorescence quantum yield of quinine sulfate in sol-gel and PMMA impregnated glasses is measured. The observed quantum yield improvement in the sol-gel matrix, compared to ethanol, is interpreted as a reduction of non-radiative relaxation channels by isolation of the molecules by the cage of the glass. PMMA impregnated sol-gel glasses show an extra improvement of the fluorescence yield, which is interpreted as a reduction of the free space and the rigid fixation of the molecules to the matrix.

  17. Fluorescence quantum yield of thioflavin T in rigid isotropic solution and incorporated into the amyloid fibrils.

    Directory of Open Access Journals (Sweden)

    Anna I Sulatskaya

    Full Text Available In this work, the fluorescence of thioflavin T (ThT was studied in a wide range of viscosity and temperature. It was shown that ThT fluorescence quantum yield varies from 0.0001 in water at room temperature to 0.28 in rigid isotropic solution (T/η→0. The deviation of the fluorescence quantum yield from unity in rigid isotropic solution suggests that fluorescence quantum yield depends not only on the ultra-fast oscillation of ThT fragments relative to each other in an excited state as was suggested earlier, but also depends on the molecular configuration in the ground state. This means that the fluorescence quantum yield of the dye incorporated into amyloid fibrils must depend on its conformation, which, in turn, depends on the ThT environment. Therefore, the fluorescence quantum yield of ThT incorporated into amyloid fibrils can differ from that in the rigid isotropic solution. In particular, the fluorescence quantum yield of ThT incorporated into insulin fibrils was determined to be 0.43. Consequently, the ThT fluorescence quantum yield could be used to characterize the peculiarities of the fibrillar structure, which opens some new possibilities in the ThT use for structural characterization of the amyloid fibrils.

  18. Microwave heating of arginine yields highly fluorescent nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Philippidis, Aggelos [Foundation for Research and Technology-Hellas, Institute of Electronic Structure and Laser (Greece); Stefanakis, Dimitrios [University of Crete, Department of Chemistry (Greece); Anglos, Demetrios, E-mail: anglos@iesl.forth.gr [Foundation for Research and Technology-Hellas, Institute of Electronic Structure and Laser (Greece); Ghanotakis, Demetrios, E-mail: ghanotakis@chemistry.uoc.gr [University of Crete, Department of Chemistry (Greece)

    2013-01-15

    Brightly fluorescent nanoparticles were produced via a single-step, single-precursor procedure based on microwave heating of an aqueous solution of the amino acid arginine. Key structural and optical properties of the resulting Arg nanoparticles, Arg-dots, are reported and discussed with emphasis on the pH dependence of their fluorescence emission. The surface of the Arg-dots was functionalised through coupling to folic acid, opening up ways for connecting fluorescent nanoparticles to cancer cells. The generality and versatility of the microwave heating procedure was further demonstrated by the synthesis of different types of carbon nanoparticles, such as CE-dots, that were produced by use of citric acid and ethanolamine as precursors and compared to the Arg-dots.

  19. Containerless Atomic-Fluorescence Property Measurements

    Science.gov (United States)

    Nordine, P.; Schiffman, R.; Walker, C.

    1987-01-01

    Report describes studies conducted to establish and verify use of laser-induced fluorescence in monitoring and controlling high-temperature containerless processes. Specimens levitated by gas jets or electromagnetic fields and heated by laser beams or electromagnetic induction while being irradiated and detected by fluorescence technique. Makes quantitative and qualitative comparisons among three new methods of temperature measurement; all rely on laser-induced fluorescence. One method gas-density thermometry with seed gas. Other two methods involve measurements of velocities of evaporating atoms or of population ratios of different electronic states.

  20. Fluorescence lifetime measurements of boronate derivatives to determine glucose concentration

    Energy Technology Data Exchange (ETDEWEB)

    Gable, J H

    2000-06-01

    A novel investigation into the fluorescence lifetimes of molecules, both established and newly designed, was performed. These molecules are the basis of a continuous, minimally invasive, glucose sensor based on fluorescence lifetime measurements. This sensor, if coupled with an automated insulin delivery device, would effectively create an artificial pancreas allowing for the constant monitoring and control of glucose levels in a person with diabetes. The proposed sensor includes a fluorescent molecule that changes its' fluorescence properties upon binding selectively and reversibly to glucose. One possible sensor molecule is N-methyl-N-(9-methylene anthryl)-2-methylenephenylboronic acid (AB). The fluorescence intensity of AB was shown to change in response to changing glucose concentrations. (James, 1994) James proposed that when glucose binds to AB the fluorescence intensity increases due to an enhancement of the N{yields}B dative bond which prevents photoinduced electron transfer (PET). PET from the amine (N) to the fluorophore (anthracene) quenches the fluorescence. The dative bond between the boron and the amine can prevent PET by involving the lone pair of electrons on the amine in interactions with the boron rather than allowing them to be transferred to the fluorophore. Results of this research show the average fluorescence lifetime of AB also changes with glucose concentration. It is proposed that fluorescence is due to two components: (1) AB with an enhanced N{yields}B interaction, and no PET, and (2) AB with a weak N{yields}B interaction, resulting in fluorescence quenching by PET. Lifetime measurements of AB as a function of both the pH of the solvent and glucose concentration in the solution were made to characterize this two component system and investigate the nature of the N{yields}B bond. Measurements of molecules similar to AB were also performed in order to isolate behavior of specific AB constituents. These molecules are 9

  1. X-ray fluorescence measurements of dissolved gas and cavitation

    Science.gov (United States)

    Duke, Daniel J.; Kastengren, Alan L.; Swantek, Andrew B.; Matusik, Katarzyna E.; Powell, Christopher F.

    2016-10-01

    The dynamics of dissolved gas and cavitation are strongly coupled, yet these phenomena are difficult to measure in-situ. Both create voids in the fluid that can be difficult to distinguish. We present an application of X-ray fluorescence in which liquid density and total noncondensible gas concentration (both dissolved and nucleated) are simultaneously measured. The liquid phase is doped with 400 ppm of a bromine tracer, and dissolved air is removed and substituted with krypton. Fluorescent emission at X-ray wavelengths is simultaneously excited from the Br and Kr with a focused monochromatic X-ray beam from a synchrotron source. We measure the flow in a cavitating nozzle 0.5 mm in diameter. From Br fluorescence, total displacement of the liquid is measured. From Kr fluorescence, the mass fraction of both dissolved and nucleated gas is measured. Volumetric displacement of liquid due to both cavitation and gas precipitation can be separated through estimation of the local equilibrium dissolved mass fraction. The uncertainty in the line of sight projected densities of the liquid and gas phases is 4-6 %. The high fluorescence yields and energies of Br and Kr allow small mass fractions of gas to be measured, down to 10-5, with an uncertainty of 8 %. These quantitative measurements complement existing optical diagnostic techniques and provide new insight into the diffusion of gas into cavitation bubbles, which can increase their internal density, pressure and lifetimes by orders of magnitude.

  2. Predicting fluorescence quantum yield for anisole at elevated temperatures and pressures

    Science.gov (United States)

    Wang, Q.; Tran, K. H.; Morin, C.; Bonnety, J.; Legros, G.; Guibert, P.

    2017-07-01

    Aromatic molecules are promising candidates for using as a fluorescent tracer for gas-phase scalar parameter diagnostics in a drastic environment like engines. Along with anisole turning out an excellent temperature tracer by Planar Laser-Induced Fluorescence (PLIF) diagnostics in Rapid Compression Machine (RCM), its fluorescence signal evolution versus pressure and temperature variation in a high-pressure and high-temperature cell have been reported in our recent paper on Applied Phys. B by Tran et al. Parallel to this experimental study, a photophysical model to determine anisole Fluorescence Quantum Yield (FQY) is delivered in this paper. The key to development of the model is the identification of pressure, temperature, and ambient gases, where the FQY is dominated by certain processes of the model (quenching effect, vibrational relaxation, etc.). In addition to optimization of the vibrational relaxation energy cascade coefficient and the collision probability with oxygen, the non-radiative pathways are mainly discussed. The common non-radiative rate (intersystem crossing and internal conversion) is simulated in parametric form as a function of excess vibrational energy, derived from the data acquired at different pressures and temperatures from the literature. A new non-radiative rate, namely, the equivalent Intramolecular Vibrational Redistribution or Randomization (IVR) rate, is proposed to characterize anisole deactivated processes. The new model exhibits satisfactory results which are validated against experimental measurements of fluorescence signal induced at a wavelength of 266 nm in a cell with different bath gases (N2, CO2, Ar and O2), a pressure range from 0.2 to 4 MPa, and a temperature range from 473 to 873 K.

  3. Laser-induced fluorescence measurement of the oil film thickness in an internal combustion engine

    Science.gov (United States)

    Ostroski, Greg M.; Ghandhi, Jaal B.

    1997-11-01

    The use of a fluorescent dopant molecule to enhance the natural fluorescence of motor oils, and allow quantitative determination of temperature and film thickens in internal combustion engines has been investigated. Measurement of the fluorescence as a function of temperature were made with neat Mobil 1, and solutions of the dopant BTBP in mineral oil and Mobil 1. The fluorescence yield of neat Mobil 1 was found to vary by 30 percent over the temperature range explored, but the spectral characteristics, as measured with bandpass filters, were unaffected by temperature. The BTBP fluorescence was found to increase significantly with temperature, and it was found the narrower regions in the spectrum increased proportionally more than the fluorescence collected over the entire spectrum, allowing a determination of temperature to be made which can then be used to correct for the change in fluorescence yield. Solutions in Mobil 1 showed a smaller increase than that observed in mineral oil.

  4. Chemical effect on the K shell fluorescence yield of Fe, Mn, Co, Cr and Cu compounds

    Indian Academy of Sciences (India)

    U Turgut

    2004-11-01

    Chemical effects on the K shell fluorescence yields of Fe, Mn, Co, Cr and Cu compounds were investigated. Samples were excited using 59.5 keV energy photons from a 241Am radioisotope source. K X-rays emitted by samples were counted by a Si(Li) detector with a resolution 160 eV at 5.9 keV. Chemical effects on the K shell fluorescence yields (K) for Fe, Mn, Co, Cr and Cu compounds were observed. The values are compared with theoretical, semiempirical fit and experimental ones for the pure elements.

  5. On the energy deposition by electrons in air and the accurate determination of the air-fluorescence yield

    Directory of Open Access Journals (Sweden)

    Arqueros F.

    2013-06-01

    Full Text Available The uncertainty in the absolute value of the air-fluorescence yield still puts a severe limit on the accuracy in the primary energy of ultra-high-energy cosmic rays. The precise measurement of this parameter in laboratory is in turn conditioned by a careful evaluation of the energy deposited in the experimental collision chamber. In this work we discuss on the calculation of the energy deposition and its accuracy. Results from an upgraded Monte Carlo algorithm that we have developed are compared with those obtained using Geant4, showing excellent agreement. These updated calculations of energy deposition are used to apply some corrections to the available measurements of the absolute fluorescence yield, allowing us to obtain a reliable world average of this important parameter.

  6. Quantum Yield Measurements of Fluorophores in Lipid Bilayers Using a Plasmonic Nanocavity.

    Science.gov (United States)

    Schneider, Falk; Ruhlandt, Daja; Gregor, Ingo; Enderlein, Jörg; Chizhik, Alexey I

    2017-03-20

    Precise knowledge of the quantum yield is important for many fluorescence-spectroscopic techniques, for example, for Förster resonance energy transfer. However, to measure it for emitters in a complex environment and at low concentrations is far from being trivial. Using a plasmonic nanocavity, we measure the absolute quantum yield value of lipid-conjugated dyes incorporated into a supported lipid bilayer. We show that for both hydrophobic and hydrophilic molecules the quantum yield of dyes inside the lipid bilayer strongly differs from its value in aqueous solution. This finding is of particular importance for all fluorescence-spectroscopic studies involving lipid bilayers, such as protein-protein or protein-lipid interactions in membranes or direct fluorescence-spectroscopic measurements of membrane physical properties.

  7. Determination of $L_{3}$ subshell X-ray production cross-sections and fluorescence yields of Pb, Th and U

    CERN Document Server

    Simsek, O

    2000-01-01

    A study of L/sub 3/ subshell X-ray production cross-sections and fluorescence yields by using characteristic K X-rays as the exciting radiation is described. Only the L/sub 3/ subshells of Pb, Th and U were excited by the characteristic K X-rays of the elements used as secondary sources. The cross-sections for the production of L/sub l/, L/sub alpha / and L/sub beta / groups of L/sub 3/ subshell X-rays of Pb, Th and U have been measured using photoionization by Rb, Nb and Mo K X-rays. The measured L/sub 3/ X-ray production cross-section values for Pb, Th and U are in good agreement with the theoretical ones evaluated using L/sub 3/ subshell fluorescence yield omega /sub 3/, fractions of the radiative width F/sub 3i/ and L/sub 3/ subshell photoionization cross-section sigma /sub 3/. The L/sub 3/ subshell fluorescence yields ( omega /sub 3/) have also been computed using the presently measured cross-section values and the theoretical L/sub 3/ subshell photoionization cross-section values. These results are comp...

  8. Determination of experimental K-shell fluorescence yield for potassium and calcium compounds

    Indian Academy of Sciences (India)

    E Tiraşoğlu; Ö Söğüt

    2008-03-01

    K-shell fluorescence yields were experimentally determined for potassium and calcium compounds using a Si(Li) X-ray detector system (FWHM=5.96 keV at 160 eV). The samples were excited by 5.96 keV photons produced by a 55Fe radioisotope source. The experimental values are systematically lower than the theoretical values.

  9. Picosecond kinetic measurements of the metalloporphyrin fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Aaviskoq, Y.Y.; Freiburg, A.M.; Savikhin, S.F.; Stel' makh, G.F.

    1986-08-01

    The authors attempt to directly measure the deactivation kinetics of the short-lived excited S/sub 2/ and S/sub 1/ states of metalloporphyrins and compare the results with those obtained by other (either direct or indirect) methods. The studies were carried out on diamagnetic metallocomplexes of tetrabenzoporphyrin (MeTBP) exhibiting measurable fluorescence from the S/sub 1/ and S/sub 2/ states. The complexes with Lu, Cd, and Zn in dilute solutions were studied at room temperature. The results of direct kinetic experiments confirm the previously obtained data on picosecond deactivation processes in photoexcited metalloporphyrins.

  10. Spectral resolved Measurement of the Nitrogen Fluorescence Emissions in Air induced by Electrons

    CERN Document Server

    Waldenmaier, Tilo; Klages, Hans

    2007-01-01

    For the calorimetric determination of the primary energy of extensive air showers, measured by fluorescence telescopes, a precise knowledge of the conversion factor (fluorescence yield) between the deposited energy in the atmosphere and the number of emitted fluorescence photons is essential. The fluorescence yield depends on the pressure and the temperature of the air as well as on the water vapor concentration. Within the scope of this work the fluorescence yield for the eight strongest nitrogen emission bands between 300 nm and 400 nm has been measured using electrons from a Sr-90 source with energies between 250 keV and 2000 keV. Measurements have been performed in dry air, pure nitrogen, and a nitrogen-oxygen mixture at pressures ranging from 2 hPa to 990 hPa. Furthermore the influence of water vapor has been studied. A new approach for the parametrization of the fluorescence yield was used to analyze the data, leading to a consistent description of the fluorescence yield with a minimal set of parameters...

  11. Variations in fluorescence quantum yield of basic fuchsin with silver nanoparticles prepared by femtosecond laser ablation.

    Science.gov (United States)

    Pathrose, Bini; Sahira, H; Nampoori, V P N; Radhakrishnan, P; Mujeeb, A

    2014-07-15

    Nano structured noble metals have very important applications in diverse fields such as photovoltaics, catalysis, electronic and magnetic devices, etc. In the present work, the application of dual beam thermal lens technique is employed for the determination of the absolute fluorescence quantum yield of the triaminotriphenylmethane dye, basic fuchsin in the presence of silver sol is studied. Silver sol is prepared by femtosecond laser ablation. It is observed that the presence of silver sol decreases the fluorescence quantum efficiency. The observed results are in line with the conclusion that the reduction in quantum yield in the quenching region is essentially due to the non-radiative relaxation of the absorbed energy. It is also observed that the presence of silver sol enhances the thermal lens signal which makes its detection easier at any concentration.

  12. Fluorescence quantum yields of natural organic matter and organic compounds: Implications for the fluorescence-based interpretation of organic matter composition

    DEFF Research Database (Denmark)

    Wünsch, Urban; Murphy, Kathleen R.; Stedmon, Colin

    2015-01-01

    Absorbance and fluorescence spectroscopy are economical tools for tracing the supply, turnover and fate of dissolved organic matter (DOM). The colored and fluorescent fractions of DOM (CDOM and FDOM, respectively) are linked by the apparent fluorescence quantum yield (AQY) of DOM, which reflects ...... to confirm matches was limited due to multiple compounds exhibiting very similar spectra. This reiterates the fact that spectral similarity alone is insufficient evidence of the presence of particular compounds, and additional evidence is required...

  13. Relativistic L -shell Auger and Coster-Kronig rates and fluorescence yields

    Science.gov (United States)

    Chen, M. H.; Laiman, E.; Crasemann, B.; Aoyagi, M.; Mark, H.

    1979-01-01

    Relativistic calculations of radiationless transition rates to L -subshell vacancy states in selected atoms with Z in the 70-96 range have been performed. The Auger and Coster-Kronig transition probabilities are calculated from perturbation theory, assuming frozen orbitals, in the Dirac-Hartree-Slater approach. Transition rates, fluorescence yields, and Coster-Kronig yields are compared with nonrelativistic theoretical results and with experiment. Relativity is found to affect the L -subshell Auger widths by (10-25)% and individual transition rates to certain j-j configurations by as much as 40% at Z = 80. The widths of L sub i vacancy states and the L sub 2 Coster-Kronig yields f33 from these relativistic calculations agree much better with experiment than earlier nonrelativistic theoretical values.

  14. Tris buffer improves fluorescence yield of ram spermatozoa when evaluating membrane integrity.

    Science.gov (United States)

    Yániz, Jesús Luis; Mateos, José Angel; Santolaria, Pilar

    2012-04-01

    This study was designed to evaluate the effect of various buffers on the fluorescence signal intensity of two fluorochromes (IP and CFDA) when used to assess the membrane integrity of ram sperm. Second ejaculates (18) from nine adult males were collected using an artificial vagina and diluted in either MOPS, TRIS, TES, HEPES, citrate, or phosphate-based extenders. Semen samples were stored at 15°C and the membrane integrity was assessed within the first 24 h of storage. Mean fluorescence intensity (FI) of PI- and CDFA-labeled sperm heads and fluorescence background noise (FBN) were determined quantitatively using Image J software. Fluorescence contrast (FC) was expressed as the difference between FI and FBN. Significantly, higher FI and FC were recorded when TRIS diluent was used, rather than the other diluents, both in the propidium- and fluorescein-labeled cells. The citrate and phosphate-based extenders showed intermediate results of FC between those of TRIS and zwitterionic (MOPS, TES and HEPES) groups for the PI-labeled sperm. However, in the CFDA-labeled sperm, the lower values of FC were obtained in the citrate and phosphate groups due to increased levels of FBN. For the membrane-damaged sperm, fluorescent labeling was limited to the sperm heads when TRIS-buffer was used, whereas in the other groups, the sperm tail was also frequently observed. It was concluded that TRIS buffer solution markedly increases the fluorescence yield of IP/CFDA-labeled sperm cells in the ram and that this should be considered when evaluating their membrane integrity.

  15. Absolute absorption and fluorescence measurements over a dynamic range of 10$^6$ with cavity-enhanced laser-induced fluorescence

    CERN Document Server

    Sanders, Scott E; Nahler, N Hendrik; Wrede, Eckart

    2013-01-01

    We describe a novel experimental setup that combines the advantages of both laser-induced fluorescence and cavity ring-down techniques. The simultaneous measurement of the ring-down and fluorescence signals from the same sample in a single laser beam delivers the calibration of the fluorescence measurement to gain absolute quantities: absorption cross section, sample density and fluorescence quantum yield. At the same time, the fluorescence measurement extends the dynamic range of a stand-alone cavity ring-down setup from typically three to at least six orders of magnitude. The methodology of this combined cavity-enhanced laser-induced fluorescence (CELIF) technique is developed and rigorously tested against the spectroscopy of 1,4-bis(phenylethynyl)benzene in a molecular beam and density measurements in a cell.

  16. Chlorophyll Fluorescence and Photon Yield of Oxygen Evolution in Iron-Deficient Sugar Beet (Beta vulgaris L.) Leaves 12

    Science.gov (United States)

    Morales, Fermín; Abadía, Anunciación; Abadía, Javier

    1991-01-01

    The response of sugar beet (Beta vulgaris L.) leaves to iron deficiency can be described as consisting of two phases. In the first phase, leaves may lose a large part of their chlorophyll while maintaining a roughly constant efficiency of photosystem II photochemistry; ratios of variable to maximum fluorescence decreased by only 6%, and photon yields of oxygen evolution decreased by 30% when chlorophyll decreased by 70%. In the second phase, when chlorophyll decreased below a threshold level, iron deficiency caused major decreases in the efficiency of photosystem II photochemistry and in the photon yield of oxygen evolution. These decreases in photosystem II photochemical efficiency were found both in plants dark-adapted for 30 minutes and in plants dark-adapted overnight, indicating that photochemical efficiency cannot be repaired in that time scale. Decreases in photosystem II photochemical efficiency and in the photon yield of oxygen evolution were similar when measurements were made (a) with light absorbed by carotenoids and chlorophylls and (b) with light absorbed only by chlorophylls. Leaves of iron-deficient plants exhibited a room temperature fluorescence induction curve with a characteristic intermediate peak I that increases with deficiency symptoms. PMID:16668527

  17. Sedimentation of Reversibly Interacting Macromolecules with Changes in Fluorescence Quantum Yield

    Science.gov (United States)

    Chaturvedi, Sumit K.; Zhao, Huaying; Schuck, Peter

    2017-04-01

    Sedimentation velocity analytical ultracentrifugation with fluorescence detection has emerged as a powerful method for the study of interacting systems of macromolecules. It combines picomolar sensitivity with high hydrodynamic resolution, and can be carried out with photoswitchable fluorophores for multi-component discrimination, to determine the stoichiometry, affinity, and shape of macromolecular complexes with dissociation equilibrium constants from picomolar to micromolar. A popular approach for data interpretation is the determination of the binding affinity by isotherms of weight-average sedimentation coefficients, sw. A prevailing dogma in sedimentation analysis is that the weight-average sedimentation coefficient from the transport method corresponds to the signal- and population-weighted average of all species. We show that this does not always hold true for systems that exhibit significant signal changes with complex formation - properties that may be readily encountered in practice, e.g., from a change in fluorescence quantum yield. Coupled transport in the reaction boundary of rapidly reversible systems can make significant contributions to the observed migration in a way that cannot be accounted for in the standard population-based average. Effective particle theory provides a simple physical picture for the reaction-coupled migration process. On this basis we develop a more general binding model that converges to the well-known form of sw with constant signals, but can account simultaneously for hydrodynamic co-transport in the presence of changes in fluorescence quantum yield. We believe this will be useful when studying interacting systems exhibiting fluorescence quenching, enhancement or Forster resonance energy transfer with transport methods.

  18. Toward autonomous measurements of photosynthetic electron transport rates: An evaluation of active fluorescence-based measurements of photochemistry

    NARCIS (Netherlands)

    Silsbe, G.M.; Oxborough, K.; Suggett, D.J.; Forster, R.M.; Ihnken, S.; Komárek, O.; Lawrenz, E.; Prášil, O.; Röttgers, R.; Šicner, M.; Simis, S.G.H.; Van Dijk, M.A.; Kromkamp, J.C.

    2015-01-01

    This study presents a methods evaluation and intercalibration of active fluorescence-based measurements of the quantum yield ( inline image) and absorption coefficient ( inline image) of photosystem II (PSII) photochemistry. Measurements of inline image, inline image, and irradiance (E) can be

  19. Novel Instrument to Measure Aerosol Fluorescence, Absorption, and Scattering Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Picarro, Inc proposes to develop the first cavity ringdown spectroscopy (CRDS) system to measure fluorescence, absorption, and scattering properties of atmospheric...

  20. Use of the fluorescence quantum yield for the determination of the number-average molecular weight of polymers of epicatechin with 4β→8 interflavin bonds

    Science.gov (United States)

    D. Cho; W.L. Mattice; L.J. Porter; Richard W. Hemingway

    1989-01-01

    Excitation at 280 nm produces a structureless emission band with a maximum at 321-324 nm for dilute solutions of catechin, epicatechin, and their oligomers in l,4-dioxane or water. The fluorescence quantum yield, Q, has been measured in these two solvents for five dimers, a trimer, a tetramer, a pentamer, a hexamer, and a polymer in which the monomer...

  1. Fluorescent Protein Based FRET Pairs with Improved Dynamic Range for Fluorescence Lifetime Measurements.

    Directory of Open Access Journals (Sweden)

    Bobin George Abraham

    Full Text Available Fluorescence Resonance Energy Transfer (FRET using fluorescent protein variants is widely used to study biochemical processes in living cells. FRET detection by fluorescence lifetime measurements is the most direct and robust method to measure FRET. The traditional cyan-yellow fluorescent protein based FRET pairs are getting replaced by green-red fluorescent protein variants. The green-red pair enables excitation at a longer wavelength which reduces cellular autofluorescence and phototoxicity while monitoring FRET. Despite the advances in FRET based sensors, the low FRET efficiency and dynamic range still complicates their use in cell biology and high throughput screening. In this paper, we utilized the higher lifetime of NowGFP and screened red fluorescent protein variants to develop FRET pairs with high dynamic range and FRET efficiency. The FRET variations were analyzed by proteolytic activity and detected by steady-state and time-resolved measurements. Based on the results, NowGFP-tdTomato and NowGFP-mRuby2 have shown high potentials as FRET pairs with large fluorescence lifetime dynamic range. The in vitro measurements revealed that the NowGFP-tdTomato has the highest Förster radius for any fluorescent protein based FRET pairs yet used in biological studies. The developed FRET pairs will be useful for designing FRET based sensors and studies employing Fluorescence Lifetime Imaging Microscopy (FLIM.

  2. One year of urban background fluorescent aerosol measurements

    Science.gov (United States)

    Pope, Francis

    2016-04-01

    Online aerosol fluorescence is a popular methodology for detecting bioaerosols in the atmosphere. In recent years there has been considerable effort into refining the technique to be able to distinguish between different bioaerosol classes such as pollen, spores and bacteria. A near continuous record of aerosol fluorescence measurements has been recorded at an urban background observation site in Birmingham, UK for the year 2015. Fluorescence measurements were performed using the Biral aerosol fluorescence spectrometer (AFS) which measures both UV and visible fluorescence resulting from the excitation of aerosol particles at 280 nm. Speciation of the fluorescent particles into different bioaerosol class is possible with the AFS but the lack of particle sizing makes the task difficult compared to other techniques. In addition to the fluorescence measurements, further campaign mode measurements were also generated for size segregated total particle numbers, ozone, nitrogen oxides and other chemical species. These measurements allow for the influence of road traffic on the concentration of fluorescent particle to be determined. This presentation will provide an in depth look into how bioaerosol concentrations and speciation (pollen, spores and bacteria) change throughout the year. These changes will be linked to local and regional meteorology and climate. In particular, the consequences of the unusually warm UK winter upon bioaerosol concentrations will be highlighted.

  3. SIMULTANEOUS MEASUREMENT OF CIRCULAR DICHROISM AND FLUORESCENCE POLARIZATION ANISOTROPY.

    Energy Technology Data Exchange (ETDEWEB)

    SUTHERLAND,J.C.

    2002-01-19

    Circular dichroism and fluorescence polarization anisotropy are important tools for characterizing biomolecular systems. Both are used extensively in kinetic experiments involving stopped- or continuous flow systems as well as titrations and steady-state spectroscopy. This paper presents the theory for determining circular dichroism and fluorescence polarization anisotropy simultaneously, thus insuring the two parameters are recorded under exactly the same conditions and at exactly the same time in kinetic experiments. The approach to measuring circular dichroism is that used in almost all conventional dichrographs. Two arrangements for measuring fluorescence polarization anisotropy are described. One uses a single fluorescence detector and signal processing with a lock-in amplifier that is similar to the measurement of circular dichroism. The second approach uses classic ''T'' format detection optics, and thus can be used with conventional photon-counting detection electronics. Simple extensions permit the simultaneous measurement of the absorption and excitation intensity corrected fluorescence intensity.

  4. Laser-fluorescence measurement of marine algae

    Science.gov (United States)

    Browell, E. V.

    1980-01-01

    Progress in remote sensing of algae by laser-induced fluorescence is subject of comprehensive report. Existing single-wavelength and four-wavelength systems are reviewed, and new expression for power received by airborne sensor is derived. Result differs by as much as factor of 10 from those previously reported. Detailed error analysis evluates factors affecting accuracy of laser-fluorosensor systems.

  5. ISOL Yield Predictions from Holdup-Time Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Spejewski, Eugene H. [Oak Ridge Associated Universities (ORAU); Carter, H Kennon [Oak Ridge Associated Universities (ORAU); Mervin, Brenden T. [Oak Ridge Associated Universities (ORAU); Prettyman, Emily S. [Oak Ridge Associated Universities (ORAU); Kronenberg, Andreas [Oak Ridge Associated Universities (ORAU); Stracener, Daniel W [ORNL

    2008-01-01

    A formalism based on a simple model is derived to predict ISOL yields for all isotopes of a given element based on a holdup-time measurement of a single isotope of that element. Model predictions, based on parameters obtained from holdup-time measurements, are compared to independently-measured experimental values.

  6. Intracellular distribution of fluorescent copper and zinc bis(thiosemicarbazonato) complexes measured with fluorescence lifetime spectroscopy.

    Science.gov (United States)

    Hickey, James L; James, Janine L; Henderson, Clare A; Price, Katherine A; Mot, Alexandra I; Buncic, Gojko; Crouch, Peter J; White, Jonathan M; White, Anthony R; Smith, Trevor A; Donnelly, Paul S

    2015-10-05

    The intracellular distribution of fluorescently labeled copper and zinc bis(thiosemicarbazonato) complexes was investigated in M17 neuroblastoma cells and primary cortical neurons with a view to providing insights into the neuroprotective activity of a copper bis(thiosemicarbazonato) complex known as Cu(II)(atsm). Time-resolved fluorescence measurements allowed the identification of the Cu(II) and Zn(II) complexes as well as the free ligand inside the cells by virtue of the distinct fluorescence lifetime of each species. Confocal fluorescent microscopy of cells treated with the fluorescent copper(II)bis(thiosemicarbazonato) complex revealed significant fluorescence associated with cytoplasmic puncta that were identified to be lysosomes in primary cortical neurons and both lipid droplets and lysosomes in M17 neuroblastoma cells. Fluorescence lifetime imaging microscopy confirmed that the fluorescence signal emanating from the lipid droplets could be attributed to the copper(II) complex but also that some degree of loss of the metal ion led to diffuse cytosolic fluorescence that could be attributed to the metal-free ligand. The accumulation of the copper(II) complex in lipid droplets could be relevant to the neuroprotective activity of Cu(II)(atsm) in models of amyotrophic lateral sclerosis and Parkinson's disease.

  7. White carbon: Fluorescent carbon nanoparticles with tunable quantum yield in a reproducible green synthesis

    Science.gov (United States)

    Meiling, Till T.; Cywiński, Piotr J.; Bald, Ilko

    2016-06-01

    In this study, a new reliable, economic, and environmentally-friendly one-step synthesis is established to obtain carbon nanodots (CNDs) with well-defined and reproducible photoluminescence (PL) properties via the microwave-assisted hydrothermal treatment of starch and Tris-acetate-EDTA (TAE) buffer as carbon sources. Three kinds of CNDs are prepared using different sets of above mentioned starting materials. The as-synthesized CNDs: C-CND (starch only), N-CND 1 (starch in TAE) and N-CND 2 (TAE only) exhibit highly homogenous PL and are ready to use without need for further purification. The CNDs are stable over a long period of time (>1 year) either in solution or as freeze-dried powder. Depending on starting material, CNDs with PL quantum yield (PLQY) ranging from less than 1% up to 28% are obtained. The influence of the precursor concentration, reaction time and type of additives on the optical properties (UV-Vis absorption, PL emission spectrum and PLQY) is carefully investigated, providing insight into the chemical processes that occur during CND formation. Remarkably, upon freeze-drying the initially brown CND-solution turns into a non-fluorescent white/slightly brown powder which recovers PL in aqueous solution and can potentially be applied as fluorescent marker in bio-imaging, as a reduction agent or as a photocatalyst.

  8. Plant growth with new fluorescent lamps : I. Fresh and dry weight yields of tomato seedlings.

    Science.gov (United States)

    Thomas, A S; Dunn, S

    1966-06-01

    Tomato seedlings were grown under seven kinds of fluorescent lamps, including two that are commercially available, and five experimental lamps. Detailed descriptions and spectral emission curves for these lamps are presented.The 78/22 lamp, which emitted most of its energy above 500 mμ, more than ten percent above 700 mμ, and had a sharp peak output at 660 mμ, generally produced superior fresh and dry weight yields. This effect may be due primarily to the high peak of energy emitted at approximately 660 mμ, combined with a considerable emission in the far-red, which in turn may be related to the red ↔ far-red reversibility phenomeon.The Com I lamp, which lacked the sharp peak output at 660 mμ and emitted more energy in the blue than the 78/22 lamp, was generally second only to the latter in promoting plant growth. A high moisture content was found in plants under this lamp in some experiments.The IRIII lamp had the sharp peak output at 660 mμ but greater output in the blue than the 78/22 lamp. The 282 lamp output was similar to the 78/22 but lacked the high peak. Both of these lamps generally gave improved results over those produced by commercial Gro-Lux, Warm-white, and FLAT lamps. This was attributed to the greater percentage of red and far-red energy emission by the former two lamps. The yields with the FLAT lamp were consistently lowest of all. This has been attributed to the high percentage of emitted energy in the blue and green portions of the spectrum.Both length of the test period (13 days versus 26 days) and light intensity (550 μw/cm(2) versus 1100 μw/cm(2)) may be important factors in determining which composition of spectral energy emission produces the greatest yields. Under low intensity and short test period the Com I light produced highest fresh- and dry-weight yields, but under high intensity and longer growth period the 78/22 lamp gave greatest yields. This effect may be due to inhibition of leaf expansion by red light in the early

  9. [Study on High-yield Cultivation Measures for Arctii Fructus].

    Science.gov (United States)

    Liu, Shi-yong; Jiang, Xiao-bo; Wang, Tao; Sun, Ji-ye; Hu, Shang-qin; Zhang, Li

    2015-02-01

    To find out the high yield cultivation measures for Arctii Fructus. Completely randomized block experiment design method was used in the field planting, to analyze the effect of different cultivation way on agronomic characters, phenological phase,quality and quantity of Arctii Fructus. Arctium lappa planted on August 28 had the best results of plant height, thousand seeds weight and yield. The highest yield of Arctii Fructus was got at the density of 1,482 plants/667 m2. Arctiin content was in an increase trend with the planting time delay and planting density increasing. The plant height, thousand seeds weight, yield and arctiin content by split application of fertilizer were significantly higher than that by one-time fertilization. Compared with open field Arctium lappa, plant height, yield, arctiin content and relative water content of plastic film mulching Arctium lappa was higher by 7.74%, 10.87%, 6.38% and 24.20%, respectively. In the topping Arctium lappa, the yield was increased by 11.09%, with 39. 89% less branching number. Early planting time and topping shortened the growth cycle of Arctium lappa plant. The high-yield cultivation measures of Arctii Fructus are: around August 28 to sowing, planting density of 1 482 plants/667 m2, split application of fertilizer for four times, covering film on surface of the soil and topping in bolting.

  10. ICF Gamma-Ray Yield Measurements on the NIF

    Science.gov (United States)

    Herrmann, H. W.; Kim, Y. H.; Hoffman, N. M.; Stoeffl, W. S.; Watts, P. W.; Carpenter, A. C.; Church, J. A.; Liebman, J.; Grafil, E.

    2011-10-01

    The primary objective of the NIF Gamma Reaction History (GRH) diagnostic is to provide bang time and burn width information in order to constrain implosion simulation parameters such as shell velocity and confinement time. This is accomplished by measuring DT fusion γ-rays with energy-thresholded Gas Cherenkov detectors that convert MeV γ-rays into UV/visible photons for high-bandwidth optical detection. For yield determination, absolute uncertainties associated with the d(t,n) α/d(t,γ)5He branching ratio and detector response are removed by cross-calibrating the GRH signal against independent neutron yield measurements of directly-driven DT exploding pushers with negligible neutron downscatter. The GRH signal can then be used to make Total DTn Yield inferences on indirectly-driven, cryogenically-layered DT implosions which achieve high areal density and hence scatter a significant fraction of DTn out of the 14 MeV primary peak. By comparing the Total DTn Yield from γ-ray measurements with the Primary DTn Yield (13-15 MeV) from neutron measurements, the Total Downscatter Fraction (TDSF) can be inferred. Results of recent measurements will be presented. This work supported by US DOE under contract DE-AC52-06NA25396.

  11. Measurement of the pressure dependence of air fluorescence emission induced by electrons

    CERN Document Server

    Ave, M; Buonomo, B; Busca, N; Cazon, L; Chemerisov, S D; Conde, M E; Crowell, R A; Di Carlo, P; Di Giulio, C; Doubrava, M; Esposito, A; Facal, P; Franchini, F J; Horandel, J; Hrabovsky, M; Iarlori, M; Kasprzyk, T E; Keilhauer, B; Klages, H; Kleifges, M; Kuhlmann, S; Mazzitelli, G; Nozka, L; Obermeier, A; Palatka, M; Petrera, S; Privitera, P; Rídky, J; Rizi, V; Rodríguez, G; Salamida, F; Schovanek, P; Spinka, H; Strazzeri, E; Ulrich, A; Yusof, Z M; Vacek, V; Valente, P; Verzi, V; Waldenmaier, T

    2007-01-01

    The fluorescence detection of ultra high energy (> 10^18 eV) cosmic rays requires a detailed knowledge of the fluorescence light emission from nitrogen molecules, which are excited by the cosmic ray shower particles along their path in the atmosphere. We have made a precise measurement of the fluorescence light spectrum excited by MeV electrons in dry air. We measured the relative intensities of 34 fluorescence bands in the wavelength range from 284 to 429 nm with a high resolution spectrograph. The pressure dependence of the fluorescence spectrum was also measured from a few hPa up to atmospheric pressure. Relative intensities and collisional quenching reference pressures for bands due to transitions from a common upper level were found in agreement with theoretical expectations. The presence of argon in air was found to have a negligible effect on the fluorescence yield. We estimated that the systematic uncertainty on the cosmic ray shower energy due to the pressure dependence of the fluorescence spectrum i...

  12. The small contribution of molecular Bremsstrahlung radiation to the air-fluorescence yield of cosmic ray shower particles

    Science.gov (United States)

    Al Samarai, Imen; Deligny, Olivier; Rosado, Jaime

    2016-10-01

    A small contribution of molecular Bremsstrahlung radiation to the air-fluorescence yield in the UV range is estimated based on an approach previously developed in the framework of the radio-detection of showers in the gigahertz frequency range. First, this approach is shown to provide an estimate of the main contribution of the fluorescence yield due to the de-excitation of the C 3Πu electronic level of nitrogen molecules to the B 3Πg one amounting to Y[ 337 ] =(6.05 ± 1.50) MeV-1 at 800 hPa pressure and 293 K temperature conditions, which compares well to previous dedicated works and to experimental results. Then, under the same pressure and temperature conditions, the fluorescence yield induced by molecular Bremsstrahlung radiation is found to be Y[330-400]MBR = 0.10 MeV-1 in the wavelength range of interest for the air-fluorescence detectors used to detect extensive air showers induced in the atmosphere by ultra-high energy cosmic rays. This means that out of ≃175 photons with wavelength between 330 and 400 nm detected by fluorescence detectors, one of them has been produced by molecular Bremsstrahlung radiation. Although small, this contribution is not negligible in regards to the total budget of systematic uncertainties when considering the absolute energy scale of fluorescence detectors.

  13. Finding of Optimal Calcium Ion Probes for Fluorescence Lifetime Measurement

    Science.gov (United States)

    Yoshiki, Keisuke; Azuma, Hiroki; Yoshioka, Kazuhiko; Hashimoto, Mamoru; Araki, Tsutomu

    We have investigated the fluorescence lifetime properties of 8 calcium ion probes, calcium-green-1, calcium green-2, calcium green-5N, calcium orange, oregon green 488 BAPTA-6F, fluo-3, fluo-4, and fluo-5N. We found that the decay time of calcium green-5N varied more sensitively with calcium concentration than calcium green-1 which was known to be a highly sensitive probe. We have also found that the center of observable range of calcium concentration by fluorescence lifetime measurement is lower than that by fluorescence intensity measurement.

  14. System and method for measuring fluorescence of a sample

    Energy Technology Data Exchange (ETDEWEB)

    Riot, Vincent J.

    2017-06-27

    The present disclosure provides a system and a method for measuring fluorescence of a sample. The sample may be a polymerase-chain-reaction (PCR) array, a loop-mediated-isothermal amplification array, etc. LEDs are used to excite the sample, and a photodiode is used to collect the sample's fluorescence. An electronic offset signal is used to reduce the effects of background fluorescence and the noises from the measurement system. An integrator integrates the difference between the output of the photodiode and the electronic offset signal over a given period of time. The resulting integral is then converted into digital domain for further processing and storage.

  15. System and method for measuring fluorescence of a sample

    Energy Technology Data Exchange (ETDEWEB)

    Riot, Vincent J

    2015-03-24

    The present disclosure provides a system and a method for measuring fluorescence of a sample. The sample may be a polymerase-chain-reaction (PCR) array, a loop-mediated-isothermal amplification array, etc. LEDs are used to excite the sample, and a photodiode is used to collect the sample's fluorescence. An electronic offset signal is used to reduce the effects of background fluorescence and the noises from the measurement system. An integrator integrates the difference between the output of the photodiode and the electronic offset signal over a given period of time. The resulting integral is then converted into digital domain for further processing and storage.

  16. Integrated optical measurement system for fluorescence spectroscopy in microfluidic channels

    DEFF Research Database (Denmark)

    Hübner, Jörg; Mogensen, Klaus Bo; Jørgensen, Anders Michael

    2001-01-01

    A transportable miniaturized fiber-pigtailed measurement system is presented which allows quantitative fluorescence detection in microliquid handling systems. The microliquid handling chips are made in silica on silicon technology and the optical functionality is monolithically integrated...... with the microfluidic channel system. This results in inherent stability and photolithographic alignment precision. Permanently attached optical fibers provide a rugged connection to the light source, detection, and data processing unit, which potentially allows field use of such systems. Fluorescence measurements...

  17. Laser-saturated fluorescence measurements in laminar sooting diffusion flames

    Science.gov (United States)

    Wey, Changlie

    1993-01-01

    The hydroxyl radical is known to be one of the most important intermediate species in the combustion processes. The hydroxyl radical has also been considered a dominant oxidizer of soot particles in flames. In this investigation the hydroxyl concentration profiles in sooting diffusion flames were measured by the laser-saturated fluorescence (LSF) method. The temperature distributions in the flames were measured by the two-line LSF technique and by thermocouple. In the sooting region the OH fluorescence was too weak to make accurate temperature measurements. The hydroxyl fluorescence profiles for all four flames presented herein show that the OH fluorescence intensities peaked near the flame front. The OH fluorescence intensity dropped sharply toward the dark region of the flame and continued declining to the sooting region. The OH fluorescence profiles also indicate that the OH fluorescence decreased with increasing height in the flames for all flames investigated. Varying the oxidizer composition resulted in a corresponding variation in the maximum OH concentration and the flame temperature. Furthermore, it appears that the maximum OH concentration for each flame increased with increasing flame temperature.

  18. Measuring the effects of extreme weather events on yields

    Directory of Open Access Journals (Sweden)

    J.P. Powell

    2016-06-01

    Full Text Available Extreme weather events are expected to increase worldwide, therefore, anticipating and calculating their effects on crop yields is important for topics ranging from food security to the economic viability of biomass products. Given the local nature of weather, particularly precipitation, effects are best measured at a local level. This paper analyzes weather events at the level of the farm for a specific crop, winter wheat. Once it has been established that extreme events are expected to continue occurring at historically high levels for farming locations throughout the Netherlands, the effects of those events on wheat yields are estimated while controlling for the other major input factors affecting yields. Econometric techniques are applied to an unbalanced panel data set of 334 farms for a period of up to 12 years. Analyzes show that the number of days with extreme high temperatures in Dutch wheat growing regions has significantly increased since the early 1900s, while the number of extreme low temperature events has fallen over that same period. The effects of weather events on wheat yields were found to be time specific in that the week in which an event occurred determined its effect on yields. High temperature events and precipitation events were found to significantly decrease yields.

  19. Neutron source capability assessment for cumulative fission yields measurements

    Energy Technology Data Exchange (ETDEWEB)

    Descalle, M A; Dekin, W; Kenneally, J

    2011-04-06

    A recent analysis of high-quality cumulative fission yields data for Pu-239 published in the peer-reviewed literature showed that the quoted experimental uncertainties do not allow a clear statement on how the fission yields vary as a function of energy. [Prussin2009] To make such a statement requires a set of experiments with well 'controlled' and understood sources of experimental errors to reduce uncertainties as low as possible, ideally in the 1 to 2% range. The Inter Laboratory Working Group (ILWOG) determined that Directed Stockpile Work (DSW) would benefit from an experimental program with the stated goal to reduce the measurement uncertainties significantly in order to make a definitive statement of the relationship of energy dependence to the cumulative fission yields. Following recent discussions between Lawrence Livermore National Laboratory (LLNL) and Los Alamos National Laboratory (LANL), there is a renewed interest in developing a concerted experimental program to measure fission yields in a neutron energy range from thermal energy (0.025 eV) to 14 MeV with an emphasis on discrete energies from 0.5 to 4 MeV. Ideally, fission yields would be measured at single energies, however, in practice there are only 'quasi-monoenergetic' neutrons sources of finite width. This report outlines a capability assessment as of June 2011 of available neutron sources that could be used as part of a concerted experimental program to measure cumulative fission yields. In a framework of international collaborations, capabilities available in the United States, at the Atomic Weapons Establishment (AWE) in the United Kingdom and at the Commissariat Energie Atomique (CEA) in France are listed. There is a need to develop an experimental program that will reduce the measurement uncertainties significantly in order to make a definitive statement of the relationship of energy dependence to the cumulative fission yields. Fission and monoenergetic neutron sources

  20. Measuring and sorting cell populations expressing isospectral fluorescent proteins with different fluorescence lifetimes.

    Directory of Open Access Journals (Sweden)

    Bryan Sands

    Full Text Available Study of signal transduction in live cells benefits from the ability to visualize and quantify light emitted by fluorescent proteins (XFPs fused to different signaling proteins. However, because cell signaling proteins are often present in small numbers, and because the XFPs themselves are poor fluorophores, the amount of emitted light, and the observable signal in these studies, is often small. An XFP's fluorescence lifetime contains additional information about the immediate environment of the fluorophore that can augment the information from its weak light signal. Here, we constructed and expressed in Saccharomyces cerevisiae variants of Teal Fluorescent Protein (TFP and Citrine that were isospectral but had shorter fluorescence lifetimes, ∼ 1.5 ns vs ∼ 3 ns. We modified microscopic and flow cytometric instruments to measure fluorescence lifetimes in live cells. We developed digital hardware and a measure of lifetime called a "pseudophasor" that we could compute quickly enough to permit sorting by lifetime in flow. We used these abilities to sort mixtures of cells expressing TFP and the short-lifetime TFP variant into subpopulations that were respectively 97% and 94% pure. This work demonstrates the feasibility of using information about fluorescence lifetime to help quantify cell signaling in living cells at the high throughput provided by flow cytometry. Moreover, it demonstrates the feasibility of isolating and recovering subpopulations of cells with different XFP lifetimes for subsequent experimentation.

  1. [Flag leaf photosynthetic characteristics, change in chlorophyll fluorescence parameters, and their relationships with yield of winter wheat sowed in spring].

    Science.gov (United States)

    Xu, Lan; Gao, Zhi-qang; An, Wei; Li, Yan-liang; Jiao, Xiong-fei; Wang, Chuang-yun

    2016-01-01

    With five good winter wheat cultivars selected from the middle and lower reaches of Yangtze River and Southwest China as test materials, a field experiment in Xinding basin area of Shanxi Province was conducted to study the photosynthetic characteristics, chlorophyll content, and chlorophyll fluorescence parameters of flag leaf at different sowing dates, as well as the correlations between these indices and yield for two years (2013-2014). The results showed that the difference in most fluorescence parameters except chlorophyll content among cultivars was significant. The correlations between these fluorescence parameters and yield were significant. The variation coefficient of chlorophyll (Chl) content was low (0.12-0.17), and that of performance index based on absorption (PIabs) was high (0.32-0.39), with the partial correlation coefficients of them with grain yield from 2013 to 2014 ranged in 0.70-0.81. Under the early sowing condition, the grain yield positively correlated with PIabs at flowering and filling stages and chlorophyll content at grain filling stage, but negatively correlated with the relative variable fluorescence at I point (Vi) at grain filling stage. About 81.1%-82.8% of grain yield were determined by the variations of PIabs, Chl, and Vi. Wheat cultivars had various performances in the treatments with different sowing dates and a consistent trend was observed in the two experimental years. Among these 5 cultivars, Yangmai 13 was suitable for early sowing, with the flag leaf photosynthetic rate (Pn), Chl, most fluorescence parame-ters, and grain yield showed obviously high levels. In conclusion, under early sowing condition chlorophyll content at grain filling stages, PIabs at flowering and filling stages, and Pn were important indices for selecting wheat cultivars with high photosynthetic efficiency.

  2. Field Measurements of Black Carbon Yields from Gas Flaring.

    Science.gov (United States)

    Conrad, Bradley M; Johnson, Matthew R

    2017-02-07

    Black carbon (BC) emissions from gas flaring in the oil and gas industry are postulated to have critical impacts on climate and public health, but actual emission rates remain poorly characterized. This paper presents in situ field measurements of BC emission rates and flare gas volume-specific BC yields for a diverse range of flares. Measurements were performed during a series of field campaigns in Mexico and Ecuador using the sky-LOSA optical measurement technique, in concert with comprehensive Monte Carlo-based uncertainty analyses. Parallel on-site measurements of flare gas flow rate and composition were successfully performed at a subset of locations enabling direct measurements of fuel-specific BC yields from flares under field conditions. Quantified BC emission rates from individual flares spanned more than 4 orders of magnitude (up to 53.7 g/s). In addition, emissions during one notable ∼24-h flaring event (during which the plume transmissivity dropped to zero) would have been even larger than this maximum rate, which was measured as this event was ending. This highlights the likely importance of superemitters to global emission inventories. Flare gas volume-specific BC yields were shown to be strongly correlated with flare gas heating value. A newly derived correlation fitting current field data and previous lab data suggests that, in the context of recent studies investigating transport of flare-generated BC in the Arctic and globally, impacts of flaring in the energy industry may in fact be underestimated.

  3. Herbicide impact on Hormosira banksii gametes measured by fluorescence and germination bioassays

    Energy Technology Data Exchange (ETDEWEB)

    Seery, Cliff R. [Institute for Water and Environmental Resource Management, Department of Environmental Sciences, University of Technology, Sydney, Westbourne Street, Gore Hill, 2065 NSW (Australia); Gunthorpe, Leanne [Primary Industries Research Victoria (PIRVic), VIC (Australia); Ralph, Peter J. [Institute for Water and Environmental Resource Management, Department of Environmental Sciences, University of Technology, Sydney, Westbourne Street, Gore Hill, 2065 NSW (Australia)]. E-mail: peter.ralph@uts.edu.au

    2006-03-15

    The innovative bioassay described here involves chlorophyll a fluorescence measurements of gametes from the macroalgae, Hormosira banksii, where gametes (eggs) were exposed to Diuron, Irgarol and Bromacil. Response was assessed as percent inhibition from control of effective quantum yield ({delta}F/Fm') of photosystem II, herein referred to as % PSII Inhibition. This was measured with the dual-channelled pulse amplitude modulated (PAM) fluorometer, ToxY-PAM. The fluorescence bioassay was run simultaneously with an established H. banksii germination bioassay to compare sensitivity, precision, and time-to-result. The fluorescence bioassay gave highly sensitive results evidenced by EC{sub 5}s (% PSII Inhibition) for Diuron, Irgarol and Bromacil being three, four and three orders of magnitude (respectively) lower than EC{sub 5}s generated from the germination bioassays. Precision of the fluorescence bioassay was demonstrated with low coefficient of variations (<30%) for all three toxicants. With regard to time, the fluorescence bioassay gave results within 6 h, as opposed to more than 50 h for the germination bioassay. - Chlorophyll a fluorescence measurements form the basis of a macroalgal bioassay with many advantages over germination-based methods.

  4. The SPIDER fission fragment spectrometer for fission product yield measurements

    Energy Technology Data Exchange (ETDEWEB)

    Meierbachtol, K.; Tovesson, F. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Shields, D. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Colorado School of Mines, Golden, CO 80401 (United States); Arnold, C. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Blakeley, R. [University of New Mexico, Albuquerque, NM 87131 (United States); Bredeweg, T.; Devlin, M. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Hecht, A.A.; Heffern, L.E. [University of New Mexico, Albuquerque, NM 87131 (United States); Jorgenson, J.; Laptev, A. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Mader, D. [University of New Mexico, Albuquerque, NM 87131 (United States); O' Donnell, J.M.; Sierk, A.; White, M. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2015-07-11

    The SPectrometer for Ion DEtermination in fission Research (SPIDER) has been developed for measuring mass yield distributions of fission products from spontaneous and neutron-induced fission. The 2E–2v method of measuring the kinetic energy (E) and velocity (v) of both outgoing fission products has been utilized, with the goal of measuring the mass of the fission products with an average resolution of 1 atomic mass unit (amu). The SPIDER instrument, consisting of detector components for time-of-flight, trajectory, and energy measurements, has been assembled and tested using {sup 229}Th and {sup 252}Cf radioactive decay sources. For commissioning, the fully assembled system measured fission products from spontaneous fission of {sup 252}Cf. Individual measurement resolutions were met for time-of-flight (250 ps FWHM), spacial resolution (2 mm FHWM), and energy (92 keV FWHM for 8.376 MeV). Mass yield results measured from {sup 252}Cf spontaneous fission products are reported from an E–v measurement.

  5. Measuring and interpreting X-ray fluorescence from planetary surfaces.

    Science.gov (United States)

    Owens, Alan; Beckhoff, Burkhard; Fraser, George; Kolbe, Michael; Krumrey, Michael; Mantero, Alfonso; Mantler, Michael; Peacock, Anthony; Pia, Maria-Grazia; Pullan, Derek; Schneider, Uwe G; Ulm, Gerhard

    2008-11-15

    As part of a comprehensive study of X-ray emission from planetary surfaces and in particular the planet Mercury, we have measured fluorescent radiation from a number of planetary analog rock samples using monochromatized synchrotron radiation provided by the BESSY II electron storage ring. The experiments were carried out using a purpose built X-ray fluorescence (XRF) spectrometer chamber developed by the Physikalisch-Technische Bundesanstalt, Germany's national metrology institute. The XRF instrumentation is absolutely calibrated and allows for reference-free quantitation of rock sample composition, taking into account secondary photon- and electron-induced enhancement effects. The fluorescence data, in turn, have been used to validate a planetary fluorescence simulation tool based on the GEANT4 transport code. This simulation can be used as a mission analysis tool to predict the time-dependent orbital XRF spectral distributions from planetary surfaces throughout the mapping phase.

  6. Breast cancer: in vitro measurements of native fluorescence

    Science.gov (United States)

    Lohmann, Wolfgang; Bohle, Rainer M.; Dreyer, Thomas; Haas, Sabine; Wallenfels, Heike; Schwemmle, Konrad; Schill, Wolf-Bernhard

    1996-12-01

    Unfixed, HE stained cryosections of breast tissue obtained from 67 patients during surgery were illuminated with 395 - 440 nm and their fluorescence response as well as the 2- dimensional fluorophore distribution were measured. The histological evaluation of the same cryosection, illuminated as usual with a transmitted light obtained from a halogen lamp, revealed 9 patients with healthy tissue, 11 with benign epithelial hyperplasia, 4 with ductal carcinoma in situ, 35 with invasive ductal carcinoma, 7 with invasive lobular carcinoma, and one with invasive tubular carcinoma. A comparison between the fluorescence and the HE images shows that both match very nicely and that the fluorescence images are also characteristic for the different pathological condition of the biopsy sample. Moreover, benign tumors e.g. fibroadenomas, exhibit a fluorescence response different from cancer and healthy tissue.

  7. The Small Contribution of Molecular Bremsstrahlung Radiation to the Air-Fluorescence Yield of Cosmic Ray Shower Particles

    CERN Document Server

    Samarai, I Al; Rosado, J

    2016-01-01

    A small contribution of molecular Bremsstrahlung radiation to the air-fluorescence yield in the UV range is estimated based on an approach previously developed in the framework of the radio-detection of showers in the gigahertz frequency range. First, this approach is shown to provide an estimate of the main contribution of the fluorescence yield due to the de-excitation of the C $^3\\Pi_{\\mathrm{u}}$ electronic level of nitrogen molecules to the B $^3\\Pi_{\\mathrm{g}}$ one amounting to $Y_{[337]}=(6.05\\pm 1.50)~$ MeV$^{-1}$ at 800 hPa pressure and 293 K temperature conditions, which compares well to previous dedicated works and to experimental results. Then, under the same pressure and temperature conditions, the fluorescence yield induced by molecular Bremsstrahlung radiation is found to be $Y_{[330-400]}^{\\mathrm{MBR}}=0.10~$ MeV$^{-1}$ in the wavelength range of interest for the air-fluorescence detectors used to detect extensive air showers induced in the atmosphere by ultra-high energy cosmic rays. This m...

  8. Fusion yield measurements on JET and their calibration

    Energy Technology Data Exchange (ETDEWEB)

    Syme, D.B., E-mail: brian.syme@ccfe.ac.uk [EURATOM-CCFE Fusion Association, Culham Science Centre, Abingdon, OXON OX14 3DB (United Kingdom); Popovichev, S. [EURATOM-CCFE Fusion Association, Culham Science Centre, Abingdon, OXON OX14 3DB (United Kingdom); Conroy, S. [EURATOM-VR Association, Department of Physics and Astronomy, Uppsala University, Box 516, SE-75120 Uppsala (Sweden); Lengar, I.; Snoj, L. [EURATOM-MHEST Association, Reactor Physics Division, Jožef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana (Slovenia); Sowden, C. [EURATOM-CCFE Fusion Association, Culham Science Centre, Abingdon, OXON OX14 3DB (United Kingdom); Giacomelli, L. [EURATOM-ENEA-CNR Association, CNR-IFP and Univ. di Milano-Bicocca, Milan (Italy); Hermon, G.; Allan, P.; Macheta, P.; Plummer, D.; Stephens, J. [EURATOM-CCFE Fusion Association, Culham Science Centre, Abingdon, OXON OX14 3DB (United Kingdom); Batistoni, P. [EURATOM-ENEA Association, Via E. Fermi,40, 00044 Frascati (Italy); Prokopowicz, R.; Jednorog, S. [EURATOM-IPPLM Association, Institute of Plasma Physics and Laser Microfusion, Hery 23, 01-497 Warsaw (Poland); Abhangi, M.R.; Makwana, R. [Institute for Plasma Research, Bhat, Gandhinagar, 382 428 Gujarat (India)

    2014-11-15

    The power output of fusion experiments and fusion reactor-like devices is measured in terms of the neutron yields which relate directly to the fusion yield. In this paper we describe the devices and methods used to make the new in situ calibration of JET in April 2013 and its early results. The target accuracy of this calibration was 10%, just as in the earlier JET calibration and as required for ITER, where a precise neutron yield measurement is important, e.g., for tritium accountancy. We discuss the constraints and early decisions which defined the main calibration approach, e.g., the choice of source type and the deployment method. We describe the physics, source issues, safety and engineering aspects required to calibrate directly the Fission Chambers and the Activation System which carry the JET neutron calibration. In particular a direct calibration of the Activation system was planned for the first time in JET. We used the existing JET remote-handling system to deploy the {sup 252}Cf source and developed the compatible tooling and systems necessary to ensure safe and efficient deployment in these cases. The scientific programme has sought to better understand the limitations of the calibration, to optimise the measurements and other provisions, to provide corrections for perturbing factors (e.g., presence of the remote-handling boom and other non-standard torus conditions) and to ensure personnel safety and safe working conditions. Much of this work has been based on an extensive programme of Monte-Carlo calculations which, e.g., revealed a potential contribution to the neutron yield via a direct line of sight through the ports which presents individually depending on the details of the port geometry.

  9. Mercury mass measurement in fluorescent lamps via neutron activation analysis

    Science.gov (United States)

    Viererbl, L.; Vinš, M.; Lahodová, Z.; Fuksa, A.; Kučera, J.; Koleška, M.; Voljanskij, A.

    2015-11-01

    Mercury is an essential component of fluorescent lamps. Not all fluorescent lamps are recycled, resulting in contamination of the environment with toxic mercury, making measurement of the mercury mass used in fluorescent lamps important. Mercury mass measurement of lamps via instrumental neutron activation analysis (NAA) was tested under various conditions in the LVR-15 research reactor. Fluorescent lamps were irradiated in different positions in vertical irradiation channels and a horizontal channel in neutron fields with total fluence rates from 3×108 cm-2 s-1 to 1014 cm-2 s-1. The 202Hg(n,γ)203Hg nuclear reaction was used for mercury mass evaluation. Activities of 203Hg and others induced radionuclides were measured via gamma spectrometry with an HPGe detector at various times after irradiation. Standards containing an Hg2Cl2 compound were used to determine mercury mass. Problems arise from the presence of elements with a large effective cross section in luminescent material (europium, antimony and gadolinium) and glass (boron). The paper describes optimization of the NAA procedure in the LVR-15 research reactor with particular attention to influence of neutron self-absorption in fluorescent lamps.

  10. Measurements of extrinsic fluorescence in Intralipid and polystyrene microspheres

    Science.gov (United States)

    Du Le, Vinh Nguyen; Nie, Zhaojun; Hayward, Joseph E.; Farrell, Thomas J.; Fang, Qiyin

    2014-01-01

    The fluorescence of Intralipid and polystyrene microspheres with sphere diameter of 1 µm at a representative lipid and microsphere concentration for simulation of mucosal tissue scattering has not been a subject of extensive experimental study. In order to elucidate the quantitative relationship between lipid and microsphere concentration and the respective fluorescent intensity, the extrinsic fluorescence spectra between 360 nm and 650 nm (step size of 5 nm) were measured at different lipid concentrations (from 0.25% to 5%) and different microsphere concentrations (0.00364, 0.0073, 0.0131 spheres per cubic micrometer) using laser excitation at 355 nm with pulse energy of 2.8 µJ. Current findings indicated that Intralipid has a broadband emission between 360 and 650 nm with a primary peak at 500 nm and a secondary peak at 450 nm while polystyrene microspheres have a single peak at 500 nm. In addition, for similar scattering properties the fluorescence of Intralipid solutions is approximately three-fold stronger than that of the microsphere solutions. Furthermore, Intralipid phantoms with lipid concentrations ~2% (simulating the bottom layer of mucosa) produce up to seven times stronger fluorescent emission than phantoms with lipid concentration ~0.25% (simulating the top layer of mucosa). The fluoresence decays of Intralipid and microsphere solutions were also recorded for estimation of fluorescence lifetime. PMID:25136497

  11. Measurement of cell volume changes by fluorescence self-quenching

    DEFF Research Database (Denmark)

    Hamann, Steffen; Kiilgaard, J.F.; Litman, Thomas

    2002-01-01

    At high concentrations, certain fluorophores undergo self-quenching, i.e., fluorescence intensity decreases with increasing fluorophore concentration. Accordingly, the self-quenching properties can be used for measuring water volume changes in lipid vesicles. In cells, quantitative determination...... of water transport using fluorescence self-quenching has been complicated by the requirement of relatively high (mM) and often toxic loading concentrations. Here we report a simple method that uses low (muM) loading concentrations of calcein-acetoxymethyl ester (calcein-AM) to obtain intracellular...... concentrations of the fluorophore calcein suitable for measurement of changes in cell water volume by self-quenching. The relationship between calcein fluorescence intensity, when excited at 490 nm (its excitation maximum), and calcein concentration was investigated in vitro and in various cultured cell types...

  12. Monte Carlo Simulation of K Fluorescence Radiation Spectrum and Fluorescence Yield%K 荧光能谱及荧光产额 MC 模拟

    Institute of Scientific and Technical Information of China (English)

    陈成; 吴金杰; 周四春; 陈法君; 王佳; 葛良全

    2015-01-01

    K荧光X射线辐射装置能够开展各类核辐射探测器的校准和研究工作,基于MCNP5模拟程序建立了K荧光发生装置的模型。荧光辐射束是影响探测器校准的关键,辐射体厚度决定荧光的产额。通过蒙特卡罗模拟Cs2 SO4辐射体材料,得到辐射束各个位置的荧光出射谱、荧光产额和纯度与辐射体厚度的变化关系。结果表明,辐射束在1m处的半径大于25 cm且散射成分对荧光能谱的干扰小,辐射体存在饱和厚度。该研究结果可对实验制作各种辐射体以及荧光的定性和定量分析具有参考作用。%K fluorescent X ray radiation device can carry out various kinds of radiation detector calibration and research work.The fluorescence of K generator model is established based on MCNP5 simulation program.The fluorescence radiation beam is the key factor to influence detector calibration, radiator thickness decide the fluo-rescence yield.Through Monte Carlo simulation,Cs2 SO4 radiator material is studied, the fluorescence radiation beam emitted spectrum at each position, the relationship between fluorescence yield and purity as a fuction of the radiator thickness are obtained.The results show that, the radiation radius of the beam at the 1m is greater than 25 cm and scattering components of interference spectrum is small, and the various radiators have a satu-rated thickness.The results of this study can provided a reference for the experimental production of various ra-diators and the qualitative and quantitative analysis of fluorescence.

  13. Ultrastable green fluorescence carbon dots with a high quantum yield for bioimaging and use as theranostic carriers

    DEFF Research Database (Denmark)

    Yang, Chuanxu; Thomsen, Rasmus Peter; Ogaki, Ryosuke

    2015-01-01

    in biomedical applications. Oligoethylenimine (OEI)–β-cyclodextrin (βCD) Cdots were synthesised using a simple and fast heating method in phosphoric acid. The synthesised Cdots showed strong green fluorescence under UV excitation with a 30% quantum yield and exhibited superior stability over a wide pH range. We......Carbon dots (Cdots) have recently emerged as a novel platform of fluorescent nanomaterials. These carbon nanoparticles have great potential in biomedical applications such as bioimaging as they exhibit excellent photoluminescence properties, chemical inertness and low cytotoxicity in comparison...... to widely used semiconductor quantum dots. However, it remains a great challenge to prepare highly stable, water-soluble green luminescent Cdots with a high quantum yield. Herein we report a new synthesis route for green luminescent Cdots imbuing these desirable properties and demonstrate their potential...

  14. Measurement of Fission Product Yields from Fast-Neutron Fission

    Science.gov (United States)

    Arnold, C. W.; Bond, E. M.; Bredeweg, T. A.; Fowler, M. M.; Moody, W. A.; Rusev, G.; Vieira, D. J.; Wilhelmy, J. B.; Becker, J. A.; Henderson, R.; Kenneally, J.; Macri, R.; McNabb, D.; Ryan, C.; Sheets, S.; Stoyer, M. A.; Tonchev, A. P.; Bhatia, C.; Bhike, M.; Fallin, B.; Gooden, M. E.; Howell, C. R.; Kelley, J. H.; Tornow, W.

    2014-09-01

    One of the aims of the Stockpile Stewardship Program is a reduction of the uncertainties on fission data used for analyzing nuclear test data [1,2]. Fission products such as 147Nd are convenient for determining fission yields because of their relatively high yield per fission (about 2%) and long half-life (10.98 days). A scientific program for measuring fission product yields from 235U,238U and 239Pu targets as a function of bombarding neutron energy (0.1 to 15 MeV) is currently underway using monoenergetic neutron beams produced at the 10 MV Tandem Accelerator at TUNL. Dual-fission chambers are used to determine the rate of fission in targets during activation. Activated targets are counted in highly shielded HPGe detectors over a period of several weeks to identify decaying fission products. To date, data have been collected at neutron bombarding energies 4.6, 9.0, 14.5 and 14.8 MeV. Experimental methods and data reduction techniques are discussed, and some preliminary results are presented.

  15. Measuring the effect of field viability on wheat yield

    DEFF Research Database (Denmark)

    Olsen, Jakob Vesterlund; Schou, Jesper Sølver

    showing a significant effect on yields. Further research may involve estimating the effect of field characteristics on the aggregated economic farm performance. The field viability index has multiple applications in e.g. benchmarking, leasing or buying arrangements, and for identifying potential land...... contributes by introducing a new joint index for field shape and field size, field viability index (FVI), aiming at measuring the effect of land fragmentation on farm performance based on field characteristics. The index is calculated for Danish wheat fields and is tested on a large sample of Danish farmers...

  16. Measurement of in vitro microtubule polymerization by turbidity and fluorescence.

    Science.gov (United States)

    Mirigian, Matthew; Mukherjee, Kamalika; Bane, Susan L; Sackett, Dan L

    2013-01-01

    Tubulin polymerization may be conveniently monitored by the increase in turbidity (optical density, or OD) or by the increase in fluorescence intensity of diamidino-phenylindole. The resulting data can be a quantitative measure of microtubule (MT) assembly, but some care is needed in interpretation, especially of OD data. Buffer formulations used for the assembly reaction significantly influence the polymerization, both by altering the critical concentration for polymerization and by altering the exact polymer produced-for example, by increasing the production of sheet polymers in addition to MT. Both the turbidity and the fluorescence methods are useful for demonstrating the effect of MT-stabilizing or -destabilizing additives.

  17. Photophysical investigation of (D-π-A) DMHP dye: Dipole moments, photochemical quantum yield and fluorescence quantum yield, by solvatochromic shift methods and DFT studies

    Science.gov (United States)

    Asiri, Abdullah M.; Sobahi, Tariq R.; Osman, Osman I.; Khan, Salman A.

    2017-01-01

    (2E)-3-(3,4-dimethoxyphenyl)-1-(2-hydroxyphenyl)prop-2-en-1-one (DMHP) was synthesized by the reaction of 3,4-dimethoxy benzaldehyde with 1-(2-hydroxyphenyl) ethanone under microwave irradiation. The structure of DMHP was established experimentally by EI-MS, FT-IR, 1H and 13C NMR spectral studies and elemental analysis and theoretically. Electronic absorption and emission spectra of DMHP were studied in different solvents on the basis of polarities, and the obtain data were used to determine the solvatochromic properties such as extinction coefficient, oscillator strength, transition dipole moment, stokes shift, fluorescence quantum yield and photochemical quantum yield. The absorption and emission maxima were red-shifted when the polarity of the solvent was increased from dioxan to DMSO; in excellent agreement the DFT findings. The DMHP experimental intramolecular charge transfer (ICT) was complemented by a natural bond orbital (NBO) analysis. Fluorescence intensities of DMHP were increase and decrease in presence of CTAB and SDS, so DMHP was used to find out the critical micelle concentration (CMC) of CTAB and SDS.

  18. Intracellular pH-determination by fluorescence measurements.

    Science.gov (United States)

    Visser, J W; Jongeling, A A; Tanke, H J

    1979-01-01

    A method was developed to determine the intracellular pH (pHi) of individual cells by use of fluorescence measurements. The method is based on the observation that the fluorescence excitation spectrum of fluorescein is pH-dependent. Fluorescence excitation spectra from individual rat bone marrow cells treated with fluorescein diacetate (FDA) were compared with those of fluorescein solutions of known pH values. Cells which were suspended in media of pH between 4.0 and 8.1 with high to normal buffering capacities had pHi values equal to those of the media. Cells suspended in media with low buffering capacities maintained a pH,i of 6.7 +/- 0.2. Preliminary results indicated that the pHi of individual cells may also be determined by using flow cytometry.

  19. Developing and Testing a Bayesian Analysis of Fluorescence Lifetime Measurements

    Science.gov (United States)

    Needleman, Daniel J.

    2017-01-01

    FRET measurements can provide dynamic spatial information on length scales smaller than the diffraction limit of light. Several methods exist to measure FRET between fluorophores, including Fluorescence Lifetime Imaging Microscopy (FLIM), which relies on the reduction of fluorescence lifetime when a fluorophore is undergoing FRET. FLIM measurements take the form of histograms of photon arrival times, containing contributions from a mixed population of fluorophores both undergoing and not undergoing FRET, with the measured distribution being a mixture of exponentials of different lifetimes. Here, we present an analysis method based on Bayesian inference that rigorously takes into account several experimental complications. We test the precision and accuracy of our analysis on controlled experimental data and verify that we can faithfully extract model parameters, both in the low-photon and low-fraction regimes. PMID:28060890

  20. Temperature and light tolerance of representative brown,green and red algae in tumble culture revealed by chlorophyll fluorescence measurements

    Institute of Scientific and Technical Information of China (English)

    PANG Shaojun; SHAN Tifeng

    2008-01-01

    Laminaria japonica,Undaria pinnatifida,Ulva lactuca,Grateloupia turuturu and Palmaria palmata are suitable species that fit the requirements of a seaweed-animal integrated aquaculture system in terms of their viable biomass,rapid growth and promising nutrient uptake rates. In this investigation,the responses of the optimal chlorophyll fluolescence yield of the five algal species in tumble culture were assessed at a temperature range of 10~30℃.The results revealed that Ulva lactuca was the most resistant species to high temperature,withstanding 30℃ for 4 h without apparent decline in the optimal chlorophyll fluorescence yield. While the arctic alga Palmaria palmata was the most vulnerable one,showing significant decline in the optimal chlorophyll fluorescence yield at 25℃ for 2 h.The cold-water species Laminaria japonica,however,demonstrated strong ability to cope with higher temperature(24~26℃)for shorter time(within 24 h)without significant decline in the optimal chlorophyll fluorescence yield.Grateloupia turuturu showed a general decrease in the optimal chiorophyll fluores-cence yield with the rising temperature from 23 to 30℃,similar to the temperate kelp Undaria pinnatifida.Changes of chio-rophyll fluorescence yields of these algae were characterized differently indicating the existence of species-unique strategy to cope with high light.Measurements of the optimal chlorophyll fluorescence yield after short exposure to direct solar irradiance revealed how long these exposures could be without significant photoinhibition or with promising recovery in photosynthetic activities. Seasonal pattern of alternation of algal species in tank culture in the Northern Hemisphere at the latitude of 36°Nwas proposed according to these basic measurements.

  1. Local blood flow measured by fluorescence excitation of nonradioactive microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Morita, Y.; Payne, B.D.; Aldea, G.S.; McWatters, C.; Husseini, W.; Mori, H.; Hoffman, J.I.; Kaufman, L. (Univ. of California, San Francisco (USA))

    1990-05-01

    An X-ray fluorescence system with low Compton background and high counting efficiency was developed to measure regional blood flow with nonradioactive microspheres. The performance of the system was tested in vitro by counting mixed aqueous solutions of either Mo, Ag, and I; Nb, Ag, and Ba; or Zr, Mo, Rh, Ag, Sn, I, and Ba, as well as a mixture of Ag and Ba nonradioactive microspheres. Mixtures containing 2-20 ppm of each element were counted for 10 min by the fluorescence system, and the individual elements in mixtures of three to seven nonradioactive elements were measured with high accuracy. The best counting statistics were obtained for Ag. For 10-min counts, the system measures as few as 120 Ag microspheres with 30% standard deviation but measures 800 Ag microspheres per sample with 3.6% standard deviation. We compared regional myocardial blood flows determined simultaneously by fluorescence and radioactive microsphere methods; the latter samples were counted by a 3-in. NaI (Tl) well detector and pulse-height analyzer. The radioactive and nonradioactive measurements showed good correlations.

  2. Upward and downward solar-induced chlorophyll fluorescence yield indices of four tree species as indicators of traffic pollution in Valencia.

    Science.gov (United States)

    Van Wittenberghe, Shari; Alonso, Luis; Verrelst, Jochem; Hermans, Inge; Delegido, Jesús; Veroustraete, Frank; Valcke, Roland; Moreno, José; Samson, Roeland

    2013-02-01

    Passive steady-state chlorophyll fluorescence (Fs) provides a direct diagnosis of the functional status of vegetation photosynthesis. With the prospect of mapping Fs using remote sensing techniques, field measurements are mandatory to understand to which extent Fs allows detecting plant stress in different environments. Trees of four common species in Valencia were classified in either a low or a high local traffic exposure class based on their leaf magnetic value. Upward and downward hyperspectral fluorescence yield (FY) and indices based on the two Fs peaks (at 687 and 741 nm) were calculated. FY indices of P. canariensis and P. x acerifolia were significantly different between the two traffic exposure classes defined, but not for C. australis nor M. alba. While chlorophyll content could not indicate the difference between low and high traffic exposure, the FY(687)/FY(741) peak ratio increased significantly (p < 0.05) for both leaf sides for the higher traffic exposure class.

  3. L-subshell fluorescence yields and Coster-Kronig transition probabilities with a reliable uncertainty budget for selected high- and medium-Z elements

    Science.gov (United States)

    Kolbe, Michael; Hönicke, Philipp; Müller, Matthias; Beckhoff, Burkhard

    2012-10-01

    Photon-in/photon-out experiments at thin specimens have been carried out to determine L-subshell fluorescence yields as well as Coster-Kronig transition probabilities of Au, Pb, Mo, and Pd using radiometrically calibrated instrumentation in the Physikalisch-Technische Bundesanstalt (PTB) laboratory at the electron storage ring BESSY II in Berlin. An advanced approach was developed in order to derive the fluorescence line intensities by means of line sets of each subshell that were corrected for self-absorption and broadened with experimentally determined detector response functions. The respective photoelectric cross sections for each subshell were determined by means of transmission measurements of the same samples without any change in the experimental operating condition. All values derived were compared to those of earlier works. A completely traceable uncertainty budget is provided for the determined values.

  4. Measurements of Fluorescent Bioaerosol Particles in the Colorado Front Range

    Science.gov (United States)

    Perring, A. E.; Emerson, J. B.; Fierer, N.; Schwarz, J. P.; Fahey, D. W.

    2013-12-01

    Bioaerosols are of atmospheric interest due to their potential importance as cloud condensation and heterogeneous ice nuclei and because they represent a sizeable fraction of coarse mode aerosol in some locations. Relatively little data exists, however, regarding diurnal, seasonal and annual cycles of bioaerosols and the meteorological processes that control them. Newly developed real-time instrumentation allows for sensitive, high time resolution detection of fluorescent bioaerosols and is uniquely suited to address key uncertainties in the sources, distributions and behavior of these particles in the atmosphere. Here we present observations of ambient fluorescent biological aerosol made on the Front Range of Colorado using a custom-modified Wideband Integrated Bioaerosol Sensor (WIBS) during the summer and fall of 2013. The summertime measurements were made from the roof of the NOAA ESRL David Skaggs Research Center in Boulder and the fall measurements were made both at the surface and aloft at the Boulder Atmospheric Observatory Tall Tower. We examine diurnal variations in loading and size distribution of fluorescent bioaerosol at the two locations. We also investigate the relationship between meteorological events and fluorescent bioaerosol. For example, we observe higher concentrations and markedly different number distributions associated with precipitation events. Simultaneous filter samples were collected for DNA sequencing and flow cytometry. To our knowledge this represents the first such comparison for the WIBS under ambient conditions and the microbial identification accomplished with the filters adds significantly to the analysis. This data set will provide useful insight into the sources, loadings and properties of fluorescent bioaerosol and the local and regional processes that drive them.

  5. A Transformer Partial Discharge Measurement System Based on Fluorescent Fiber

    Directory of Open Access Journals (Sweden)

    Fan Liu

    2012-05-01

    Full Text Available Based on the physical phenomena of optical effects produced by the partial discharge (PD and on the characteristics of fluorescent fiber sensing of weak fluorescent signals, a PD measurement system using a fluorescent fiber sensor was designed. The main parameters of the sensing system were calculated, an experimental testing platform for PD simulation in the lab was established, and PD signals were then detected through ultra-high frequency (UHF and optical methods under a needle-plate discharge model. PD optical pulses in transformer oil contained signal-peak and multi-peak pulse waveforms. Compared with UHF detection results, the number of PD pulses and the elapsed PD pulse phase time revealed a good corresponding relationship. However, PD signal amplitudes presented the opposite, thus indicating that PD UHF signals reflected pulse amplitude value, whereas PD optical signals reflected pulse energy magnitude. The n-u-φ three-dimensional distributions indicated that most of the PD signals concentrated in the nearby industrial frequency voltage peak value. Overall, the proposed fluorescent fiber sensing system design can be used successfully in transformer PD signal detection.

  6. Using violet laser-induced chlorophyll fluorescence emission spectra for crop yield assessment of cowpea (Vigna unguiculata (L) Walp) varieties

    Science.gov (United States)

    Anderson, Benjamin; Buah-Bassuah, Paul K.; Tetteh, Jonathan P.

    2004-07-01

    The use of violet laser-induced chlorophyll fluorescence (LICF) emission spectra to monitor the growth of five varieties of cowpea in the University of Cape Coast Botanical Garden is presented. Radiation from a continuous-wave violet laser diode emitting at 396 nm through a fibre is closely incident on in vivo leaves of cowpea to excite chlorophyll fluorescence, which is detected by an integrated spectrometer with CCD readout. The chlorophyll fluorescence spectra with peaks at 683 and 731 nm were used for growth monitoring of the cowpea plants over three weeks and analysed using Gaussian spectral functions with curve fitted parameters to determine the peak positions, area under the spectral curve and the intensity ratio F683/F731. The variation in the intensity ratio of the chlorophyll bands showed sensitive changes indicating the photosynthetic activity of the cowpea varieties. A discussion of the fluorescence result as compared to conventional assessment is presented with regard to discrimination between the cowpea varieties in terms of crop yield performance.

  7. Fluorescence decay time measurement - a new optical sensing scheme

    Science.gov (United States)

    Draxler, Sonja; Lippitsch, Max E.

    1994-02-01

    Optical sensors often suffer from poor long-term stability. This drawback can be overcome by using fluorescence decay-time measurement as the sensing principle. In this way calibration- free chemical sensors can be developed. The sensing scheme has been used so far mainly in connection with dynamic quenching, for example in oxygen sensors. We have succeeded in extending it to ground-state indicator-analyte reactions, thus obtaining stable optical sensors for decay-time sensing of various analytes.

  8. Investigations on exponential lifetime measurements for fluorescence thermometry

    Science.gov (United States)

    Fernicola, V. C.; Rosso, L.; Galleano, R.; Sun, T.; Zhang, Z. Y.; Grattan, K. T. V.

    2000-07-01

    Lifetime-based methods have been, on the whole, one of the most successful schemes for fiber optic temperature sensing, using fluorescent materials whose response is intensity independent. Several approaches for determining the fluorescence lifetime, and with that the measurand, have been investigated. An experimental comparison of direct and indirect measurement methods, i.e., involving actual signals from representative optical media instead of simply using Monte Carlo simulations, has been carried out. Direct fitting methods, including Marquardt, log-fit and Prony, were used to estimate the fluorescence lifetime of a Cr3+:YAG-based sensor system and the results were compared. An agreement to better than 0.5% between Marquardt and log-fit algorithms and an agreement of about 1.5% between Marquardt and Prony approaches was found. Thus, a temperature reproducibility, of 0.5 and 1.2 °C, respectively, can be obtained with the Cr3+:YAG sensor system. An indirect measurement approach based on a phase-locked (analog-to-digital signal processor) (A-DSP) was also tested. It was found that when the A-DSP output is used to estimate the lifetime, it performs only slightly better than using direct fitting methods. On the contrary, when the whole A-DSP sensor system was directly calibrated against temperature, the measurement accuracy improves by at least a factor of 10.

  9. Cell-free measurements of brightness of fluorescently labeled antibodies

    Science.gov (United States)

    Zhou, Haiying; Tourkakis, George; Shi, Dennis; Kim, David M.; Zhang, Hairong; Du, Tommy; Eades, William C.; Berezin, Mikhail Y.

    2017-02-01

    Validation of imaging contrast agents, such as fluorescently labeled imaging antibodies, has been recognized as a critical challenge in clinical and preclinical studies. As the number of applications for imaging antibodies grows, these materials are increasingly being subjected to careful scrutiny. Antibody fluorescent brightness is one of the key parameters that is of critical importance. Direct measurements of the brightness with common spectroscopy methods are challenging, because the fluorescent properties of the imaging antibodies are highly sensitive to the methods of conjugation, degree of labeling, and contamination with free dyes. Traditional methods rely on cell-based assays that lack reproducibility and accuracy. In this manuscript, we present a novel and general approach for measuring the brightness using antibody-avid polystyrene beads and flow cytometry. As compared to a cell-based method, the described technique is rapid, quantitative, and highly reproducible. The proposed method requires less than ten microgram of sample and is applicable for optimizing synthetic conjugation procedures, testing commercial imaging antibodies, and performing high-throughput validation of conjugation procedures.

  10. Angle-resolved polarimetry measurements of antenna-mediated fluorescence

    CERN Document Server

    Mohtashami, Abbas; Koenderink, A Femius

    2015-01-01

    Optical phase-array antennas can be used to control not only the angular distribution but also the polarization of fluorescence from quantum emitters. The emission pattern of the resulting system is determined by the properties of the antenna, the properties of the emitters and the strength of the antenna-emitter coupling. Here we show that Fourier polarimetry can be used to characterize these three contributions. To this end, we measured the angle and Stokes-parameter resolved emission of bullseye plasmon antennas as well as spiral antennas excited by an ensemble of emitters. We estimate the antenna-emitter coupling on basis of the degree of polarization, and determine the effect of anisotropy in the intrinsic emitter orientation on polarization of the resulting emission pattern. Our results not only provide new insights in the behavior of bullseye and spiral antennas, but also demonstrate the potential of Fourier polarimetry when characterizing antenna mediated fluorescence.

  11. Containerless high temperature property measurements by atomic fluorescence

    Science.gov (United States)

    Nordine, P. C.; Schiffman, R. A.

    1982-01-01

    Laser induced fluorescence techniques were developed for the containerless study of high temperature processes, material properties, levitation, and heating techniques for containerless earth-based experimentation. Experiments were performed in which fluorescence of atomic aluminum, mercury, or tungsten were studied. These experiments include measurements of: (1) Al atom evaporation from CW CO2 laser heated and aerodynamically levitated sapphire and alumina spheres, and self-supported sapphire filaments, (2) Al atom reaction with ambient oxygen in the wake of a levitated specimen, (3) Hg atom concentrations in the wake of levitated alumina and sapphire spheres, relative to the ambient Hg atom concentration, (4) Hg atom concentrations in supersonic levitation jets, and (5) metastable, electronically excited W atom concentrations produced by evaporation of an electrically heated tungsten filament.

  12. Influence of the surface hydrophobicity on fluorescence correlation spectroscopy measurements

    Science.gov (United States)

    Boutin, Céline; Jaffiol, Rodolphe; Plain, Jérome; Royer, Pascal

    2007-02-01

    Fluorescence correlation spectroscopy (FCS) is a powerful experimental technique used to analyze the diffusion at the single molecule level in solution. FCS is based on the temporal autocorrelation of fluorescent signal generated by dye molecules diffusing through a small confocal volume. These measurements are mostly carried out in a chambered coverglass, close to the glass substrate. In this report, we discuss how the chemical nature of the glass-water interface may interact with the free diffusion of molecules. Our results reveal a strong influence, up to a few μm from the interface, of the surface hydrophobicity degree. This influence is assessed through the relative weight of the two dimension diffusion process observed at the vicinity of the surface.

  13. How to Measure Separations and Angles Between Intramolecular Fluorescent Markers

    DEFF Research Database (Denmark)

    Mortensen, Kim; Sung, J.; Spudich, J.A.

    2016-01-01

    Structure and function of an individual biomolecule can be explored with minimum two fluorescent markers of different colors. Since the light of such markers can be spectrally separated and imaged simultaneously, the markers can be colocalized. Here, we describe the method used for such two...... in a time-lapse movie, we simultaneously determine both the relative (x,y)-separation of the fluorophores and their individual orientations in space, both with accuracy and precision. The relative positions and orientations of two domains of the same molecule are thus time-resolved. Using short double...... firmly; (b) we established how to map with super-resolution between color-separated channels, which should be useful for all dual-color colocalization measurements with either fixed or freely rotating fluorescent molecules. Throughout, we use only simple means: from each color-separated microscope image...

  14. Bloodstain age analysis: toward solid state fluorescent lifetime measurements

    Science.gov (United States)

    Guo, Kevin; Zhegalova, Natalia; Achilefu, Samuel; Berezin, Mikhail Y.

    2013-03-01

    One of the most pressing unsolved challenges in forensic science is the determination of time since deposition (TSD) of bloodstains at crime scenes. Despite a number of high profile cases over the past couple hundred years involving controversy over TSD methods, no reliable quantitative method has been established. We present here an approach that has yet to be explored by forensic scientist: measuring the fluorescence lifetime of solid-state blood. Such a method would allow for on-site measurements of bloodstains utilizing the appropriate device, and would allow for rapid results returned in real-time to investigators.

  15. submitter Measurement of LYSO Intrinsic Light Yield Using Electron Excitation

    CERN Document Server

    Martinez Turtos, Rosana; Pizzichemi, Marco; Ghezzi, Alessio; Pauwels, Kristof; Auffray, Etiennette; Lecoq, Paul; Paganoni, Marco

    2016-01-01

    The determination of the intrinsic light yield $(LY_{int})$ of scintillating crystals, i.e. number of optical photons created per amount of energy deposited, constitutes a key factor in order to characterize and optimize their energy and time resolution. However, until now measurements of this quantity are affected by large uncertainties and often rely on corrections for bulk absorption and surface/edge state. The novel idea presented in this contribution is based on the confinement of the scintillation emission in the central upper part of a 10 mm cubic crystal using a 1.5 MeV electron beam with diameter of 1 mm. A black non-reflective pinhole aligned with the excitation point is used to fix the light extraction solid angle (narrower than total reflection angle), which then sets a light cone travel path through the crystal. The final number of photoelectrons detected using a Hamamatsu R2059 photomultiplier tube (PMT) was corrected for the extraction solid angle, the Fresnel reflection coefficient and quantum...

  16. Can we Predict Quantum Yields Using Excited State Density Functional Theory for New Families of Fluorescent Dyes?

    Science.gov (United States)

    Kohn, Alexander W.; Lin, Zhou; Shepherd, James J.; Van Voorhis, Troy

    2016-06-01

    For a fluorescent dye, the quantum yield characterizes the efficiency of energy transfer from the absorbed light to the emitted fluorescence. In the screening among potential families of dyes, those with higher quantum yields are expected to have more advantages. From the perspective of theoreticians, an efficient prediction of the quantum yield using a universal excited state electronic structure theory is in demand but still challenging. The most representative examples for such excited state theory include time-dependent density functional theory (TDDFT) and restricted open-shell Kohn-Sham (ROKS). In the present study, we explore the possibility of predicting the quantum yields for conventional and new families of organic dyes using a combination of TDDFT and ROKS. We focus on radiative (kr) and nonradiative (knr) rates for the decay of the first singlet excited state (S_1) into the ground state (S_0) in accordance with Kasha's rule. M. Kasha, Discuss. Faraday Soc., 9, 14 (1950). For each dye compound, kr is calculated with the S_1-S_0 energy gap and transition dipole moment obtained using ROKS and TDDFT respectively at the relaxed S_1 geometry. Our predicted kr agrees well with the experimental value, so long as the order of energy levels is correctly predicted. Evaluation of knr is less straightforward as multiple processes are involved. Our study focuses on the S_1-T_1 intersystem crossing (ISC) and the S_1-S_0 internal conversion (IC): we investigate the properties that allow us to model the knr value using a Marcus-like expression, such as the Stokes shift, the reorganization energy, and the S_1-T_1 and S_1-S_0 energy gaps. Taking these factors into consideration, we compare our results with those obtained using the actual Marcus theory and provide explanation for discrepancy. T. Kowalczyk, T. Tsuchimochi, L. Top, P.-T. Chen, and T. Van Voorhis, J. Chem. Phys., 138, 164101 (2013). M. Kasha, Discuss. Faraday Soc., 9, 14 (1950).

  17. Nonphotochemical quenching of excitation energy in photosystem II. A picosecond time-resolved study of the low yield of chlorophyll a fluorescence induced by single-turnover flash in isolated spinach thylakoids.

    Science.gov (United States)

    Vasil'ev, S; Bruce, D

    1998-08-04

    Chlorophyll a fluorescence emission is widely used as a noninvasive measure of a number of parameters related to photosynthetic efficiency in oxygenic photosynthetic organisms. The most important component for the estimation of photochemistry is the relative increase in fluorescence yield between dark-adapted samples which have a maximal capacity for photochemistry and a minimal fluorescence yield (F0) and light-saturated samples where photochemistry is saturated and fluorescence yield is maximal (Fm). However, when photosynthesis is saturated with a short (less than 50 micro(s)) flash of light, which induces only one photochemical turnover of photosystem II, the maximal fluorescence yield is significantly lower (Fsat) than when saturation is achieved with a millisecond duration multiturnover flash (Fm). To investigate the origins of the difference in fluorescence yield between these two conditions, our time-resolved fluorescence apparatus was modified to allow collection of picosecond time-resolved decay kinetics over a short time window immediately following a saturating single-turnover flash (Fsat) as well as after a multiturnover saturating pulse (Fm). Our data were analyzed with a global kinetic model based on an exciton radical pair equilibrium model for photosystem II. The difference between Fm and Fsat was modeled well by changing only the rate constant for quenching of excitation energy in the antenna of photosystem II. An antenna-based origin for the quenching was verified experimentally by the observation that addition of the antenna quencher 5-hydroxy-1,4-naphthoquinone to thylakoids under Fm conditions resulted in decay kinetics and modeled kinetic parameters very similar to those observed under Fsat conditions in the absence of added quinone. Our data strongly support the origin of low fluorescence yield at Fsat to be an antenna-based nonphotochemical quenching of excitation energy in photosystem II which has not usually been considered explicitly in

  18. The Detectability of Neon Fluorescence and Measurement of the Solar Photospheric Neon Abundance

    CERN Document Server

    Drake, Jeremy J

    2007-01-01

    Monte Carlo calculations of the Ne K$\\alpha$ line fluoresced by coronal x-rays and emitted near the temperature minimum region of the solar atmosphere have been employed to investigate the use of this feature to measure directly the solar photospheric Ne abundance. Though very weak, comparison with spectral line databases indicates that at plasma temperatures typical of the quiet Sun and cool active regions ($\\leq 2\\times 10^6$ K) the line is isolated and unblended. A canonical solar chemical composition yields an equivalent width of $\\sim 6$ m\\AA (0.3 eV) when observed at heliocentric angles $\\sim 0$. For a 1 arcmin field of view, photon fluxes at Earth are of order 0.2 ph s$^{-1}$ for the quiet Sun, rendering the Ne K$\\alpha$ fluorescent line a quite feasible means for determining the solar photospheric Ne content.

  19. Understanding Solar Induced Fluorescence: Building up from Leaf Scale Measurements (Invited)

    Science.gov (United States)

    Berry, J. A.; Van der Tol, C.; Frankenberg, C.; Joiner, J.; Guanter, L.

    2013-12-01

    Measurements of chlorophyll fluorescence have long been a key method for probing the mechanisms of photosynthesis in laboratory studies. Recent advances in satellite spectroscopy have enabled retrieval of chlorophyll fluorescence from terrestrial ecosystems at a global scale. Analyses of these retrievals show promising potential as an indicator of photosynthetic rate and of its response to environmental stress. This talk will explore the mechanistic basis for interpreting and modeling of solar induced chlorophyll fluorescence ( SIF). SIF is essentially a leak of photons from photosynthetic membranes, and it is, therefore, related to the flux of photons absorbed by chlorophyll and to biochemical processes that regulate the processing of these photons in macromolecuar complexes associated with photosystem II. Thus: SIF = aPAR * φF, where aPAR is the flux of absorbed photosynthetically active radiation and φF, is the yield (light-use efficiency) of fluorescence. (For simplicity we will ignore the transport of fluorescence from its sources to the sensor for the moment). This expression for SIF is similar to a common expression for photosynthesis or gross primary productivity, GPP = aPAR * LUE, where LUE, is the light-use-efficiency for CO2 uptake. These equations can be combined and simplified to illustrate the relationship between SIF and GPP; GPP =SIF *LUE / φF. The extent to which GPP is proportional to SIF hinges on the stability of the ratio, LUE / φF, and it leads to the key question to be considered here. What is the relationship between the light-use-efficiency for photosynthesis and that for fluorescence? Satellite retrievals of SIF occur at mid-day, conditions where the capacity for CO2 fixation usually limits the rate of photosynthesis. Under this condition the rate of the photo-acts must be down-regulated to protect from photo-damage. This balancing the source with the sink is accomplished by opening non-photochemical trapping centers that compete with

  20. Fluorescent ester dye-based assays for the in vitro measurement of Neospora caninum proliferation.

    Science.gov (United States)

    Mota, Caroline M; Ferreira, Marcela D; Costa, Lourenço F; Barros, Patrício S C; Silva, Murilo V; Santiago, Fernanda M; Mineo, José R; Mineo, Tiago W P

    2014-09-15

    Techniques for the measurement of parasite loads in different experimental models have evolved throughout the years. The quantification of stained slides using regular cytological stains is currently the most common technique. However, this modality of evaluation is labor-intensive, and the interpretation of the results is subjective because the successes of the assays mainly rely on the abilities of the professionals involved. Moreover, the novel genetic manipulation techniques that are commonly applied for closely related Toxoplasma gondii have not yet been developed for Neospora caninum. Thus, we aimed to develop a simple protocol for parasite quantification using pre-stained N. caninum tachyzoites and fluorescent probes based on ester compounds (i.e., CFSE and DDAO). For this purpose, we employed a quantification procedure based on flow cytometry analysis. Pre-stained parasites were also examined with a fluorescent microscope, which revealed that both dyes were detectable. Direct comparison of the numbers of CFSE+ and DDAO+ cells to the values obtained with classical cytology techniques yielded statistically comparable results that also accorded with genomic DNA amplification results. Although the fluorescence emitted by DDAO was more intense and provided better discrimination between the populations of parasitized cells, CFSE+ tachyzoites were detected for several days. In conclusion, this study describes a simple, fast, low-cost and reproducible protocol for N. caninum quantification that is based on parasite pre-staining with fluorescent ester-based probes.

  1. Precise measurement of {gamma}(K{yields}e {nu}({gamma}))/{gamma}(K{yields}{mu} {nu}({gamma})) and study of K{yields}e {nu} {gamma}

    Energy Technology Data Exchange (ETDEWEB)

    Ambrosino, F.; Massarotti, P.; Meola, S.; Napolitano, M. [Dipartimento di Scienze Fisiche dell' Universita ' ' Federico II' ' , Napoli (Italy); INFN Sezione di Napoli, Napoli (Italy); Antonelli, A.; Antonelli, M.; Bencivenni, G.; Bloise, C.; Bossi, F.; Capon, G.; Capussela, T.; Ciambrone, P.; De Lucia, E.; De Simone, P.; Dreucci, M.; Felici, G.; Gatti, C.; Giovannella, S.; Jacewicz, M.; Lanfranchi, G.; Miscetti, S.; Moulson, M.; Murtas, F.; Palutan, M.; Santangelo, P.; Sciascia, B.; Sibidanov, A.; Spadaro, T.; Venanzoni, G. [Laboratori Nazionali di Frascati dell' INFN, Frascati (Italy); Archilli, F. [Dipartimento di Fisica dell' Universita ' ' Tor Vergata' ' , Rome (Italy); INFN Sezione di Roma Tor Vergata, Rome (Italy); Beltrame, P.; Denig, A.; Mueller, S. [Johannes Gutenberg-Universitaet, Institut fuer Kernphysik, Mainz (Germany); Bini, C.; De Santis, A.; De Zorzi, G.; Di Domenico, A.; Fiore, S.; Franzini, P.; Gauzzi, P. [Dipartimento di Fisica dell' Universita ' ' La Sapienza' ' , Rome (Italy); INFN Sezione di Roma, Rome (Italy); Bocchetta, S.; Ceradini, F.; Di Micco, B.; Nguyen, F. [Dipartimento di Fisica dell' Universita ' ' Roma Tre' ' , Rome (Italy); INFN Sezione di Roma Tre, Rome (Italy); Branchini, P.; Graziani, E.; Passeri, A.; Tortora, L. [INFN Sezione di Roma Tre, Rome (Italy); Capriotti, D. [Dipartimento di Fisica dell' Universita ' ' Roma Tre' ' , Rome (Italy); Di Donato, C. [INFN Sezione di Napoli, Napoli (Italy); Kulikov, V. [Institute for Theoretical and Experimental Physics, Moscow (Russian Federation); Lee-Franzini, J. [Laboratori Nazionali di Frascati dell' INFN, Frascati (Italy); State University of New York, Physics Department, Stony Brook (United States); Martini, M.; Patera, V.; Versaci, R. [Laboratori Nazionali di Frascati dell' INFN, Frascati (Italy); Dipartimento di Energetica dell' Universita ' ' La Sapienza' ' , Rome (Italy); Valente, P. [INFN Sezione di Roma, Rome (Italy)

    2009-12-15

    We present a precise measurement of the ratio R{sub K}={gamma}(K{yields}e{nu}({gamma}))/{gamma}(K{yields}{mu}{nu}({gamma})) and a study of the radiative process K{yields}e{nu}{gamma}, performed with the KLOE detector. The results are based on data collected at the Frascati e{sup +}e{sup -} collider DA {phi}NE for an integrated luminosity of 2.2 fb{sup -1}. We find R{sub K}=(2.493{+-}0.025{sub stat}{+-}0.019{sub syst}) x 10{sup -5}, in agreement with the Standard Model expectation. This result is used to improve constraints on parameters of the Minimal Supersymmetric Standard Model with lepton flavor violation. We also measured the differential decay rate d {gamma}(K{yields}e{nu}{gamma})/dE{sub {gamma}} for photon energies 10

  2. Measuring Phagosomal pH by Fluorescence Microscopy.

    Science.gov (United States)

    Canton, Johnathan; Grinstein, Sergio

    2017-01-01

    Dual wavelength ratiometric imaging has become a powerful tool for the study of pH in intracellular compartments. It allows for the dynamic imaging of live cells while accounting for changes in the focal plane, differential loading of the fluorescent probe, and photobleaching caused by repeated image acquisitions. Ratiometric microscopic imaging has the added advantage over whole population methods of being able to resolve individual cells and even individual organelles. In this chapter we provide a detailed discussion of the basic principles of ratiometric imaging and its application to the measurement of phagosomal pH, including probe selection, the necessary instrumentation, and calibration methods.

  3. Measuring diffusion with polarization-modulation dual-focus fluorescence correlation spectroscopy.

    Science.gov (United States)

    Korlann, You; Dertinger, Thomas; Michalet, Xavier; Weiss, Shimon; Enderlein, Jörg

    2008-09-15

    We present a new technique, polarization-modulation dual-focus fluorescence correlation spectroscopy (pmFCS), based on the recently intro-duced dual-focus fluorescence correlation spectroscopy (2fFCS) to measure the absolute value of diffusion coefficients of fluorescent molecules at pico- to nanomolar concentrations. Analogous to 2fFCS, the new technique is robust against optical saturation in yielding correct values of the diffusion coefficient. This is in stark contrast to conventional FCS where optical saturation leads to an apparent decrease in the determined diffusion coefficient with increasing excitation power. However, compared to 2fFCS, the new technique is simpler to implement into a conventional confocal microscope setup and is compatible with cw-excitation, only needing as add-ons an electro-optical modulator and a differential interference contrast prism. With pmFCS, the measured diffusion coefficient (D) for Atto655 maleimide in water at 25?C is determined to be equal to (4.09 +/- 0.07) x 10(-6)cm(2)/s, in good agreement with the value of 4.04 x 10-6cm2/s as measured by 2fFCS.

  4. Residual Gas Fluorescence for Profile Measurements at the GSI UNILAC

    CERN Document Server

    Forck, P

    2002-01-01

    The high beam currents, delivered at the LINAC at GSI (UNILAC) can destroy intercepting diagnostics within one macro-pulse. As an alternative for a non-destructive profile measurement the methode for residual-gas-fluorescence is investigated. The fluorescence light is emitted by the N2 molecules of the residual gas at the blue wavelength range and can be monitored with a modern CCD-camera. The images are transferred via digital bus (IEEE 1394 'FireWire') and the profiles are generated by analysis of the images with a modern software tool (National Instruments 'LabView'). Due to the short beam pulses (about 0.2 ms) the light intensities emitted by the residual gas are low and require a high amplification (gain >106) which is realized with an image intensifier with double MCP (multi channel plate), connected with a fiber taper to the CCD-chip. The design parameters of the optics and electronics are discussed as well as the advantages of the digital data transmission. Measurements with heavy ion beams of several...

  5. Ion range measurements using fluorescent nuclear track detectors

    DEFF Research Database (Denmark)

    Klimpki, G.; Osinga, J.-M.; Herrmann, R.;

    2013-01-01

    Fluorescent nuclear track detectors (FNTDs) show excellent detection properties for heavy charged particles and have, therefore, been investigated in this study in terms of their potential for in-vivo range measurements. We irradiated FNTDs with protons as well as with C, Mg, S, Fe and Xe ion beams...... (3–9 MeV/u) over a broad range of fluences (4.5e5–1.0e11 cm−2) with the detectors' optical c-axis positioned perpendicular to the beam direction. All measured ion ranges (for single track as well as track bulk intensity irradiations) deviate less than 3% from tabulated SRIM data (Ziegler et al., 2009...

  6. Dynamic fluorescence imaging for multiparametric measurement of tumor vasculature

    Science.gov (United States)

    Choi, Myunghwan; Choi, Kyungsun; Ryu, Seung-Wook; Lee, Jungwhoi; Choi, Chulhee

    2011-04-01

    Angiogenesis is essential for tumor growth and a promising target for cancer therapy. Blood vessel monitoring is an indispensable tool for evaluation and development of anti-angiogenic drugs. Here, we report a new noninvasive in vivo imaging tool, named dynamic fluorescence imaging (DyFI), for the simultaneous measurement of multiple vascular parameters including vascular density, perfusion rate, and permeability using spatiotemporal profiles of indocyanine green. Using DyFI in a tumor xenograft model, we quantitatively measured multiple vascular parameters in tumors and normal tissues with high spatial resolution. The multimodality of this method allowed us to find negative spatial correlations between perfusion and permeability. Moreover, DyFI was effective for revealing the early effects of an anti-angiogenic drug. We suggest that DyFI could be a useful tool for the preclinical development of anti-angiogenic drugs.

  7. Quantitative laser-induced fluorescence measurements of nitric oxide in a heavy-duty Diesel engine

    NARCIS (Netherlands)

    Verbiezen, K.; Klein-Douwel, R. J. H.; van Viet, A. P.; Donkerbroek, A. J.; Meerts, W. L.; Dam, N. J.; ter Meulen, J. J.

    2007-01-01

    We present quantitative, in-cylinder, UV-laser-induced fluorescence measurements of nitric oxide in a heavy-duty Diesel engine. Processing of the raw fluorescence signals includes a detailed correction, based on additional measurements, for the effect of laser beam and fluorescence attenuation, and

  8. Determination of the yield locus by means of temperature measurement

    NARCIS (Netherlands)

    Banabic, D.; Huetink, J.

    2006-01-01

    The paper presents a theoretical background of the thermo-graphical method of determining the yield locus. The analytical expression of the temperature variation of the specimen deformed in the elastic state is determined starting from the first law of thermodynamics. The experimental method for det

  9. Measurement and quantification of fluorescent changes in ocular tissue using a novel confocal instrument

    Science.gov (United States)

    Buttenschoen, Kim K.; Girkin, John M.; Daly, Daniel J.

    2014-05-01

    Our sight is a major contributor to our quality of life. The treatment of diseases like macular degeneration and glaucoma, however, presents a challenge as the delivery of medication to ocular tissue is not well understood. The instrument described here will help quantify targeted delivery by non-invasively and simultaneously measuring light reflected from and fluorescence excited in the eye, used as position marker and to track compounds respectively. The measurement concept has been proven by monitoring the diffusion of fluorescein and a pharmaceutical compound for treating open angle glaucoma in vitro in a cuvette and in ex vivo porcine eyes. To obtain a baseline of natural fluorescence we measured the change in corneal and crystalline lens autofluorescence in volunteers over a week. We furthermore present data on 3D ocular autofluorescence. Our results demonstrate the capability to measure the location and concentration of the compound of interest with high axial and temporal resolution of 178 μm and 0.6 s respectively. The current detection limit is 2 nM for fluorescein, and compounds with a quantum yield as low as 0.01 were measured to concentrations below 1 μM. The instrument has many applications in assessing the diffusion of fluorescent compounds through the eye and skin in vitro and in vivo, measuring autofluorescence of ocular tissues and reducing the number of animals needed for research. The instrument has the capability of being used both in the clinical and home care environment opening up the possibility of measuring controlled drug release in a patient friendly manner.

  10. Effect of biofilm on fluorescence measurements derived from fast repetition rate fluorometers

    Digital Repository Service at National Institute of Oceanography (India)

    Patil, J.S.; Saino, T.

    >), maximum fluorescence (Fm), variable fluorescence (Fv= Fm – F0), quantum yield(Fv/Fm) and functional absorption cross section (σPSII)]. Biofilms with chlorophyll > 0.1 μg cm-2

  11. Investigating the intersystem crossing rate and triplet quantum yield of Protoporphyrin IX by means of pulse train fluorescence technique

    Science.gov (United States)

    Gotardo, Fernando; Cocca, Leandro H. Z.; Acunha, Thiago V.; Longoni, Ana; Toldo, Josene; Gonçalves, Paulo F. B.; Iglesias, Bernardo A.; De Boni, Leonardo

    2017-04-01

    Photophysical investigations of PPIX were described in order to determine the triplet conversion efficiency. Time resolved fluorescence and pulse train fluorescence were employed to characterize the main mechanism responsible for deactivation of the first singlet excited state (excited singlet and triplet states). Single pulse and Z-Scan analysis were employed to measure the singlet excited state absorption cross-sections. Theoretical calculations were performed in order to get some properties of PPIX in ground state, first singlet and triplet excited state. A TD-DFT result shows a great possibility of ISC associated to out-of-plane distortions in porphyrinic ring. Furthermore, the B and Q bands in the calculated spectrum are assigned to the four frontier molecular orbitals as proposed by Gouterman for free-based porphyrins.

  12. Limitation of fluorescence spectrophotometry in the measurement of naphthenic acids in oil sands process water.

    Science.gov (United States)

    Lu, Weibing; Ewanchuk, Andrea; Perez-Estrada, Leonidas; Sego, Dave; Ulrich, Ania

    2013-01-01

    Fluorescence spectrophotometry has been proposed as a quick screening technique for the measurement of naphthenic acids (NAs). To evaluate the feasibility of this application, the fluorescence emission spectra of NAs extracted from three oil sands process water sources were compared with that of commercial NAs. The NAs resulting from the bitumen extraction process cannot be differentiated because of the similarity of the fluorescence spectra. Separation of the fluorescent species in NAs using high performance liquid chromatography with fluorescence detector proved unsuccessful. The acidic fraction of NAs is fluorescent but the basic fraction of NAs is not fluorescent, implying that aromatic acids in NAs give rise to the fluorescent signals. The concentrations of NAs in oil sands process water were measured by Fourier transform infrared spectroscopy (FTIR), fluorescence spectrophotometry and ultra high performance liquid chromatography-time of flight/mass spectrometry (UPLC-TOF/MS). Commercial Merichem and Kodak NAs are the best standards to use when measuring NAs concentration with FTIR and fluorescence spectrophotometry. In addition, the NAs concentrations measured by fluorescence spectrophotometry are about 30 times higher than those measured by FTIR and UPLC-TOF/MS. The findings in this study underscore the limitation of fluorescence spectrophotometry in the measurement of NAs.

  13. [Diagnosis of occlusal caries lesions using laser fluorescence measurements].

    Science.gov (United States)

    Naphausen, M T P; Riemersma, M; Verdonschot, E H

    2002-01-01

    Recently, a device for detecting occlusal caries lesions (DIAGNOdent) has been introduced. The reproducibility and validity of this laser-fluorescence device were investigated. In the in vivo part of the study, 45 sites at the occlusal surfaces of permanent molar teeth in 13 patients were measured by 2 observers using 2 DIAGNOdent devices, one produced in 1998 and one in 1999. The interobserver reliability between both devices and both observers was established. In the in vitro part of the study, 49 permanent molars were measured by 2 observers using 2 DIAGNOdent devices. In addition, visual inspection was performed. The teeth were sectioned to measure the histological depth and area of the caries lesions. The reproducibility of both DIAGNOdent devices was high, and so was the interobserver reliability. The correlation between DIAGNOdent measurements and the actual depth of the caries lesions was lower than that of visual inspection. The correlation with the enamel part of the lesion exceeded that of the dentine part. It was concluded that the validity of the DIAGNOdent, expressed as the area under the Receiver Operating Characteristic (ROC) curve, was not statistically significantly different from that of visual inspection. Because of the high reproducibility, dental practitioners who wish to use the DIAGNOdent for monitoring caries lesions, this investigation indicates that an old device may be replaced by a new one, provided that the same tip will be used.

  14. In Situ Measurement of Airway Surface Liquid [K+] Using a Ratioable K+-sensitive Fluorescent Dye*

    OpenAIRE

    Namkung, Wan; Song, Yuanlin; Mills, Aaron D.; Padmawar, Prashant; Finkbeiner, Walter E.; Verkman, A. S.

    2009-01-01

    The airway surface liquid (ASL) is the thin fluid layer lining airway surface epithelial cells, whose volume and composition are tightly regulated and may be abnormal in cystic fibrosis (CF). We synthesized a two-color fluorescent dextran to measure ASL [K+], TAC-Lime-dextran-TMR, consisting of a green-fluorescing triazacryptand K+ ionophore-Bodipy conjugate, coupled to dextran, together with a red fluorescing tetramethylrhodamine reference chromophore. TAC-Lime-dextran-TMR fluorescence was K...

  15. Note: Rapid measurement of fluorescence lifetimes using SiPM detection and waveform sampling

    Science.gov (United States)

    Tsai, H.-M.; Souris, J. S.; Kim, H.-J.; Cheng, S.-H.; Chen, L.; Lo, L.-W.; Chen, C.-T.; Kao, C.-M.

    2017-09-01

    In fluorescence spectroscopy and imaging, fluorescence lifetime measurement—assessing the average time fluorophores spend in their excited state before returning to their ground state—offers a number of advantages over quantifying fluorescence intensities that include resistance to photo-bleaching and independence from fluorophore concentration, excitation intensity, and measurement methodology. Despite growing interest, fluorescence lifetime techniques frequently mandate relatively complex instrumentation, slow data acquisition rates, and significant data analyses. In this work, we demonstrate the feasibility of measuring fluorescence lifetimes using off-the-shelf analog silicon photomultipliers and switched-capacitor array waveform sampling techniques, with precision matching that of much larger and more elaborate commercial instruments.

  16. A two-photon laser induced fluorescence diagnostic with improved sensitivity, localization, and measurement rate

    Science.gov (United States)

    Elliott, Drew; Scime, Earl; Short, Zachary

    2016-10-01

    A two-photon absorption laser induced fluorescence diagnostic has been developed for measuring neutrals in fusion plasmas. Implementation of this diagnostic on the HIT-SI3 spheromak has demonstrated the sensitivity of the diagnostic and shown that measurements taken over several plasma pulses are possible. These measurements yielded an unexpected loss of signal when complex collection optics were utilized. Simulations show that this loss of signal can be explained by chromatic aberrations caused by the disparate Kr and D emission. This loss of signal has been addressed with the development of a new calibration scheme involving xenon gas. The Xe calibration scheme emission occurs at 656.00 nm while the deuterium emission is 656.09 nm. This nearly identical emission allows for advanced optical techniques such as confocal collection/injection and spatial filtering to be employed without loss of signal. Spatial filtering has been demonstrated to decrease noise while improving measurement localization, while confocal collection/injection allows for probing and measuring to occur through one viewport. The Xe scheme also allows for a Doppler-free hydrogen measurement. Doppler-free measurements eliminate the need to scan the laser spectrally thus greatly increasing the rate of measurement.

  17. In situ Measurements of Phytoplankton Fluorescence Using Low Cost Electronics

    Directory of Open Access Journals (Sweden)

    Dana L. Wright

    2013-06-01

    Full Text Available Chlorophyll a fluorometry has long been used as a method to study phytoplankton in the ocean. In situ fluorometry is used frequently in oceanography to provide depth-resolved estimates of phytoplankton biomass. However, the high price of commercially manufactured in situ fluorometers has made them unavailable to some individuals and institutions. Presented here is an investigation into building an in situ fluorometer using low cost electronics. The goal was to construct an easily reproducible in situ fluorometer from simple and widely available electronic components. The simplicity and modest cost of the sensor makes it valuable to students and professionals alike. Open source sharing of architecture and software will allow students to reconstruct and customize the sensor on a small budget. Research applications that require numerous in situ fluorometers or expendable fluorometers can also benefit from this study. The sensor costs US$150.00 and can be constructed with little to no previous experience. The sensor uses a blue LED to excite chlorophyll a and measures fluorescence using a silicon photodiode. The sensor is controlled by an Arduino microcontroller that also serves as a data logger.

  18. Novel fluo-4 analogs for fluorescent calcium measurements.

    Science.gov (United States)

    Martin, Vladimir V; Beierlein, Michael; Morgan, Josh L; Rothe, Anca; Gee, Kyle R

    2004-12-01

    We report new fluorescent calcium indicators based on fluo-4. Attachment of a carboxamide or methylenecarboxamide moiety to the BAPTA chelator portion of fluo-4 allowed for the attachment of dextrans, protein-reactive moieties, and biotin. In particular, a high affinity fluo-4 dextran conjugate was prepared and shown to be functional in brain slices. All new probes were characterized spectroscopically and exhibited large fluorescence increases upon calcium-binding. The biotinylated version of fluo-4 formed a persistent streptavidin complex which still responded to increasing calcium concentrations with a large fluorescence increase.

  19. Electron beam dispersion measurements in nitrogen using two-dimensional imaging of N2(+) fluorescence

    Science.gov (United States)

    Clapp, L. H.; Twiss, R. G.; Cattolica, R. J.

    Experimental results are presented related to the radial spread of fluorescence excited by 10 and 20 KeV electron beams passing through nonflowing rarefied nitrogen at 293 K. An imaging technique for obtaining species distributions from measured beam-excited fluorescence is described, based on a signal inversion scheme mathematically equivalent to the inversion of the Abel integral equation. From fluorescence image data, measurements of beam radius, integrated signal intensity, and spatially resolved distributions of N2(+) first-negative-band fluorescence-emitting species have been made. Data are compared with earlier measurements and with an heuristic beam spread model.

  20. Measuring cell viability with membrane impermeable zinc fluorescent indicator.

    Science.gov (United States)

    Stork, Christian J; Li, Yang V

    2006-09-15

    Recent findings suggest that the accumulation of cytoplasmic zinc [Zn2+]i is a ubiquitous component in the cell death cascade. Zn2+ can be liberated from intracellular stores following oxidative stress and contribute to cell death processes. Here we show that the membrane/cell impermeable Zn2+ fluorescent indicator Newport Green (NG), which is non-toxic and impermeable to the membranes of healthy cells, can label unhealthy cells in tissue slices in a manner comparable to the traditional viability indicator propidium iodide (PI). Using confocal microscopy, we detected PI labeled nuclei colocalized with NG fluorescence. Our results indicate that cells which absorbed PI into their nuclei also allowed cell-impermeable Zn2+ dye to penetrate their plasma membranes, subsequently exhibiting cytosolic and nuclear fluorescence. As in PI staining, we observed marked increases in NG fluorescence in damaged/dead cells of tissue slices. Two other cell impermeable fluorescent Zn2+ dyes, Fluozin-3 and Zinpyr-4, also stained cytosolic Zn2+ in PI labeled cells. Our data indicates that the application of a Zn2+ fluorescent indicator is a fast, simple, non-toxic and reliable method for visualizing cell viability within in vitro tissue preparations. Accordingly, we demonstrate that intracellular accumulation of Zn2+ correlates with neuronal death.

  1. Effect of cultivation measures on index of photosynthesis and yield of sunflower

    OpenAIRE

    Aksyonov I.

    2007-01-01

    Photosynthetic activity is the decisive factor of yield increase in sunflower plants. This activity determines the application of agrotechnical measures such as row spacing and plant density. Experiments have proved that agrotechnical measures allow to control the growth, development and yield of sunflower hybrids and varieties. Row spacing and plants density affect the index of photosynthesis and the yield of sunflower agrophytocoenoses. Cultivation of sunflower at the row spacing of 15 cm i...

  2. Measurements of OH and HO2 yields from the gas phase ozonolysis of isoprene

    Directory of Open Access Journals (Sweden)

    P. W. Seakins

    2009-08-01

    Full Text Available The reactions of ozone with alkenes are an important source of hydroxyl (OH radicals; however, quantification of their importance is hindered by uncertainties in the absolute OH yield. Hydroxyl radical yields for the gas-phase ozonolysis of isoprene are determined in this paper by four different methods: (1 The use of cyclohexane as an OH scavenger, and the production of cyclohexanone, (2 The use of 1,3,5-trimethylbenzene as an OH tracer, and the diminution in its concentration, (3 A kinetic method in which the OH yield was obtained by performing a series of pseudo-first-order experiments in the presence or absence of an OH scavenger (cyclohexane, (4 The OH and HO2 yields were determined by fitting the temporal OH and HO2 profiles following direct detection of absolute OH and HO2 concentrations by laser induced fluorescence at low pressure (Fluorescence Assay by Gas Expansion-FAGE. The following OH yields for the ozonolysis of isoprene were obtained, relative to alkene consumed, for each method: (1 Scavenger (0.25 ± 0.04, (2 Tracer (0.25 ± 0.03, (3 Kinetic study (0.27 ± 0.02, and (4 Direct observation (0.26 ± 0.02, the error being one standard deviation. An averaged OH yield of 0.26 ± 0.02 is recommended at room temperature and atmospheric pressure and this result is compared with recent literature determinations. The HO2 yield was directly determined for the first time using FAGE to be 0.26 ± 0.03.

  3. Measurements of OH and HO2 yields from the gas phase ozonolysis of isoprene

    Directory of Open Access Journals (Sweden)

    P. W. Seakins

    2010-02-01

    Full Text Available The reactions of ozone with alkenes are an important source of hydroxyl (OH radicals; however, quantification of their importance is hindered by uncertainties in the absolute OH yield. Hydroxyl radical yields for the gas-phase ozonolysis of isoprene are determined in this paper by four different methods: (1 The use of cyclohexane as an OH scavenger, and the production of cyclohexanone, (2 The use of 1,3,5-trimethylbenzene as an OH tracer, and the diminution in its concentration, (3 A kinetic method in which the OH yield was obtained by performing a series of pseudo-first-order experiments in the presence or absence of an OH scavenger (cyclohexane, (4 The OH and HO2 yields were determined by fitting the temporal OH and HO2 profiles following direct detection of absolute OH and HO2 concentrations by laser induced fluorescence at low pressure (Fluorescence Assay by Gas Expansion- FAGE. The following OH yields for the ozonolysis of isoprene were obtained, relative to alkene consumed, for each method: (1 Scavenger (0.25±0.04, (2 Tracer (0.25±0.03, (3 Kinetic study (0.27±0.02, and (4 Direct observation (0.26±0.02, the error being one standard deviation. An averaged OH yield of 0.26±0.02 is recommended at room temperature and atmospheric pressure and this result is compared with recent literature determinations. The HO2 yield was directly determined for the first time using FAGE to be 0.26±0.03.

  4. Absolute measurement of the DT primary neutron yield on the National Ignition Facility

    Directory of Open Access Journals (Sweden)

    Leeper R.J.

    2013-11-01

    Full Text Available The measurement of the absolute neutron yield produced in inertial confinement fusion target experiments conducted on the National Ignition Facility (NIF is essential in benchmarking progress towards the goal of achieving ignition on this facility. This paper describes three independent diagnostic techniques that have been developed to make accurate and precise DT neutron yield measurements on the NIF.

  5. Forage quality and composition measurements as predictors of ethanol yield from maize (Zea mays L.) stover

    National Research Council Canada - National Science Library

    Lorenz, Aaron J; Anex, Rob P; Isci, Asli; Coors, James G; de Leon, Natalia; Weimer, Paul J

    2009-01-01

    .... Our objective was to evaluate whether forage quality and compositional measurements could be used to estimate ethanol yield of maize stover as measured by a simplified pretreatment and simultaneous...

  6. Laser induced fluorescence measurements of the mixing of fuel oil with air

    Energy Technology Data Exchange (ETDEWEB)

    Arnold, A.; Bombach, R.; Hubschmid, W.; Kaeppeli, B. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    We report on measurements of the mixing of fuel oil with air at atmospheric pressure in an industrial premixed gas turbine burner. The concentration of the vaporized fuel oil was measured with laser induced fluorescence. We reason that the fuel oil concentration can be considered with good accuracy as proportional to the fluorescence intensity. (author) 6 fig., 3 refs.

  7. X-ray Fluorescence Measurements of Turbulent Methane-Oxygen Shear Coaxial Flames (Briefing Charts)

    Science.gov (United States)

    2015-03-01

    Briefing Charts 3. DATES COVERED (From - To) March 2015-May 2015 4. TITLE AND SUBTITLE X-ray Fluorescence Measurements of Turbulent Methane -Oxygen Shear...1 DISTRIBUTION A: Approved for public release; distribution unlimited. Clearance # X-ray Fluorescence Measurements of Turbulent Methane -Oxygen Shear

  8. Determination of biological activity from fluorescence-lifetime measurements in Saccharomyces cerevisiae

    Science.gov (United States)

    Rudek, F.; Baselt, T.; Lempe, B.; Taudt, C.; Hartmann, P.

    2015-03-01

    The importance of fluorescence lifetime measurement as an optical analysis tool is growing. Many applications already exist in order to determine the fluorescence lifetime, but the majority of these require the addition of fluorescence-active substances to enable measurements. Every usage of such foreign materials has an associated risk. This paper investigates the use of auto-fluorescing substances in Saccharomyces cerevisiae (Baker's yeast) as a risk free alternative to fluorescence-active substance enabled measurements. The experimental setup uses a nitrogen laser with a pulse length of 350 ps and a wavelength of 337 nm. The excited sample emits light due to fluorescence of NADH/NADPH and collagen. A fast photodiode collects the light at the output of an appropriate high-pass edge-filter at 400 nm. Fluorescence lifetimes can be determined from the decay of the measurement signals, which in turn characterizes the individual materials and their surrounding environment. Information about the quantity of the fluorescence active substances can also be measured based on the received signal intensity. The correlation between the fluorescence lifetime and the metabolic state of Saccharomyces cerevisiae was investigated and is presented here.

  9. Fluorescence lifetime measurements of intrinsically unstructured proteins: application to α-synuclein.

    Science.gov (United States)

    Schreurs, Sarah; Kluba, Malgorzata; Meuvis, Jessika; Engelborghs, Yves

    2012-01-01

    Lifetimes of fluorescent states and their fluorescence intensities are strictly coupled and very sensitive to the environment of the fluorophores. The advantage of measuring lifetimes, next to intensities, comes from the fact that it can reveal heterogeneity and dynamic properties of this environment. In this way lifetime analysis can be used to characterize static and dynamic conformational properties and heterogeneity of fluorescent groups in different areas of a protein and as a function of time for an evolving protein. The phenomena that determine the lifetime of a label are its intrinsic properties, dynamic quenching by neighboring groups, exposure to the solvent, as well as Förster resonance energy transfer (FRET) between different groups. The basic principles of these fluorescence phenomena can be found extensively described in the excellent book of Lakowicz (Principles of fluorescence spectroscopy, 3rd edn. Springer, New York, 2006). The fluorescent groups involved are either natural amino acid side chains like tryptophan (Trp) or tyrosine (Tyr), or fluorescent labels covalently engineered into the protein. Even a single fluorescent group can show indications of heterogeneity in the local environment. If several natural fluorescent groups are present, the properties of the individual groups can be separated using site-directed mutagenesis, and additivity of their contributions can be analyzed (Engelborghs, Spectrochim Acta A Mol Biomol Spectrosc 57(11):2255-2270, 2001). If no fluorescent group is naturally present, site-directed mutagenesis can be used to introduce either a fluorescent amino acid or a cysteine allowing chemical labeling.

  10. [Effects of plastic film mulching and rain harvesting modes on chlorophyll fluorescence characteristics, yield and water use efficiency of dryland maize].

    Science.gov (United States)

    Li, Shang-Zhong; Fan, Ting-Lu; Wang, Yong; Zhao, Gang; Wang, Lei; Tang, Xiao-Ming; Dang, Yi; Zhao, Hui

    2014-02-01

    The differences on chlorophyll fluorescence parameters, yield and water use efficiency of dryland maize were compared among full plastic film mulching on double ridges and planting in catchment furrows (FFDRF), half plastic film mulching on double ridges and planting in catchment furrows (HFDRF), plastic film mulching on ridge and planting in film-side (FS), and flat planting with no plastic film mulching (NM) under field conditions in dry highland of Loess Plateau in 2007-2012. The results showed that fluorescence yield (Fo), the maximum fluorescence yield (Fm), light-adapted fluorescence yield when PS II reaction centers were totally open (F), light-adapted fluorescence yield when PS II reaction centers closed (Fm'), the maximal photochemical efficiency of PS II (Fv/Fm), the actual photochemical efficiency of PS II in the light (Phi PS II), the relative electron transport rate (ETR), photochemical quenching (qP) and non-photochemical quenching (qN) in maize leaves of FFDRF were higher than that of control (NM), and the value of 1-qP was lower than that of control, at 13:00, chlorophyll fluorescence parameters values of FFDRF was significantly higher than control, which were increased by 5.3%, 56.8%, 10.7%, 36.3%, 23.6%, 56.7%, 64.4%, 45.5%, 23.6% and -55.6%, respectively, compared with the control. Yield and water use efficiency of FFDRF were the highest in every year no matter dry year, normal year, humid year and hail disaster year. Average yield and water use efficiency of FFDRF were 12,650 kg x hm(-2) and 40.4 kg x mm(-1) x hm(-2) during 2007-2012, increased by 57.8% and 61.6% compared with the control, respectively, and also significantly higher compared with HFDRF and PS. Therefore, it was concluded that FFDRF had significantly increased the efficiency of light energy conversion and improved the production capacity of dryland maize.

  11. Vase Life Extension and Chlorophyll Fluorescence Yield of Bougainvillea Flower as Influenced by Ethanol to Attain Maximum Environmental Beautification as Ornamental Components

    Directory of Open Access Journals (Sweden)

    A. B.M. Hossain

    2008-01-01

    Full Text Available The study was conducted to investigate the effect of ethanol at different concentrations (ET on bougainvillea flower longevity and delay senescence in storage condition. The treatments were water control, 2% ET, 4% ET, 8% ET, 10% ET, 20% ET, 30% ET, 40% ET, 50% ET and 70% ET. Flower longevity was 2 days more in 4, 8% and 10% ethanol than water control and other concentrations of ethanol. Petal wilting and senescence were occurred 2 days later in 4, 8 and 10% ET than in water control. Percent petal's color changed was later in water 4, 8% and 10% than in control, 2, 20, 30, 40, 50 and 70% ET. Chlorophyll fluorescence intensity (photosynthetic yield followed by time (ms at different ethanol concentrations was higher in 4, 8 and 10% ET than in water control and other concentrations. Fo (lower fluorescence was lower in 4, 8 and 10% ET than in water and other concentrations. However, Fm and Fv [(higher fluorescence and relative variable fluorescence (Fm-Fo] were higher in 4, 8 and 10% ET than in other ET concentrations. Fv/Fm (quantum yield or photosynthetic yield was higher in 4, 8 and 10% ET than in other ET concentrations. The result showed flower vase life was significantly affected by ethanol concentrations and longevity was higher in 4, 8 and 10% ethanol than in water control and other concentrations.

  12. Remote measurement of photosynthetic efficiency using laser induced fluorescence transient (LIFT) technique.

    Science.gov (United States)

    Pieruschka, R.; Rascher, U.; Klimov, D.; Kolber, Z. S.; Berry, J. A.

    2007-12-01

    An understanding of spatial and temporal diversity of photosynthetic processes, water and energy exchange of complex plant canopies is essential for carbon and climate models. Remote sensing from space or aircraft platforms provides the only practical way to characterize the vast extent of plant canopies around the globe, but the basis for relating physiological processes to remote sensing is still largely theoretical. Experiments that bridge this gap are needed. Chlorophyll fluorescence measurements have been widely applied to quantify photosynthetic efficiency and non- photochemical energy dissipation non-destructively in photosynthetically active organisms. The most commonly used Pulse Amplitude Modulated (PAM) technique provides a saturating light pulse and is not practical at the canopy scale. We report here on a recently developed technique, Laser Induced Fluorescence Transient (LIFT), capable of remote measurement of photosynthetic efficiency of selected leaves at a distance of up to 50 m and we present here continuous studies on plans growing under natural conditions during the beginning of the winter season and the onset of summer drought in this Mediterranean climate. i) Lichens showed a strong diurnal variation in photosynthetic efficiency which correlated with relative humidity; ii) Photosynthetic efficiency of annual grass decreased with progressing drought stress; iii) An oak canopy showed very little variation of quantum yield from leaf out in spring to summer; iv) The combined effect of low temperature and high light intensity during an early winter strongly reduced the photosynthetic efficiency of four different species in response to chilling stress. These measures with the LIFT correlated well with (more limited) sampling by PAM fluoromentry and gas exchange. The ability to make continuous, automatic and remote measurements of photosynthetic efficiency of leaves with the LIFT provides a new approach for studying the heterogeneity of

  13. Two-Dimensional Fluorescence Spectroscopy for Measuring Uranium Isotopes in Femtosecond Laser Ablation

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, Mark C.; Brumfield, Brian E.; Harilal, Sivanandan S.; Hartig, Kyle C.; Jovanovic, Igor

    2017-05-30

    We present the first two-dimensional fluorescence spectroscopy measurements of uranium isotopes in femtosecond laser ablation plasmas. A new method of signal normalization is presented to reduce noise in absorption-based measurements of laser ablation.

  14. Frequency domain fluorescence lifetime microwell-plate platform for respirometry measurements

    Science.gov (United States)

    Chatni, M. R.; Yale, G.; Van Ryckeghem, A.; Porterfield, D. M.

    2010-04-01

    Traditionally micro-well plate based platforms used in biology utilize fluorescence intensity based methods to measure processes of biological relevance. However, fluorescence intensity measurements suffer from calibration drift due to a variety of factors. Photobleaching and self-quenching of the fluorescent dyes cause the intensity signal to drop over the lifetime of sensor immobilized inside the well. Variation in turbidity of the sample during the course of the measurement affects the measured fluorescence intensity. In comparison, fluorescence lifetime measurements are not significantly affected by these factors because fluorescence lifetime is a physico-chemical property of the fluorescent dye. Reliable and inexpensive frequency domain fluorescence lifetime instrumentation platforms are possible because the greater tolerance for optical alignment, and because they can be performed using inexpensive light sources such as LEDs. In this paper we report the development of a frequency domain fluorescence lifetime well-plate platform utilizing an oxygen sensitive transition-metal ligand complex fluorophore with a lifetime in the microsecond range. The fluorescence lifetime dye is incorporated in a polymer matrix and immobilized on the base of micro-well of a 60 well micro-well plate. Respiration measurements are performed in both aqueous and non-aqueous environment. Respirometry measurements were recorded from single Daphnia magna egg in hard water. Daphnia is an aquatic organism, important in environmental toxicology as a standard bioassay and early warning indicator for water quality monitoring. Also respirometry measurements were recorded from Tribolium castaneum eggs, which are common pests in the processed flour industry. These eggs were subjected to mitochondrial electron transport chain inhibitor such as potassium cyanide (KCN) and its effects on egg respiration were measured in real-time.

  15. Measurement of protein-like fluorescence in river and waste water using a handheld spectrophotometer.

    Science.gov (United States)

    Baker, Andy; Ward, David; Lieten, Shakti H; Periera, Ryan; Simpson, Ellie C; Slater, Malcolm

    2004-07-01

    Protein-like fluorescence intensity in rivers increases with increasing anthropogenic DOM inputs from sewerage and farm wastes. Here, a portable luminescence spectrophotometer was used to investigate if this technology could be used to provide both field scientists with a rapid pollution monitoring tool and process control engineers with a portable waste water monitoring device, through the measurement of river and waste water tryptophan-like fluorescence from a range of rivers in NE England and from effluents from within two waste water treatment plants. The portable spectrophotometer determined that waste waters and sewerage effluents had the highest tryptophan-like fluorescence intensity, urban streams had an intermediate tryptophan-like fluorescence intensity, and the upstream river samples of good water quality the lowest tryptophan-like fluorescence intensity. Replicate samples demonstrated that fluorescence intensity is reproducible to +/- 20% for low fluorescence, 'clean' river water samples and +/- 5% for urban water and waste waters. Correlations between fluorescence measured by the portable spectrophotometer with a conventional bench machine were 0.91; (Spearman's rho, n = 143), demonstrating that the portable spectrophotometer does correlate with tryptophan-like fluorescence intensity measured using the bench spectrophotometer.

  16. L sub-shell fluorescence cross-section measurements for elements, Z = 62-67, at tuned photon energies

    Science.gov (United States)

    Bansal, Himani; Tiwari, M. K.; Mittal, Raj

    2017-09-01

    L sub-shell X-ray fluorescence (XRF) cross-sections for 6 elements with Z = 62-67 have been measured at tuned photon energies on synchrotron Beamline-16, Indus-2, RRCAT, India. Three incident photon energies at the intervals of 0.1 keV were tuned in each region; > EL1, EL2 and EL3 where ELi are Li (i = 1-3) absorption edge energies of element. No single measurement is available in literature for present incident photon energies and elements, therefore, certainty and reliability of the measurements have been judged from three different aspects. One, from comparison of measured cross-sections with calculated theoretical values. Second, evaluation of Coster-Kronig yield (fij's) and fluorescence yield (ωi's) fine parameters from measured XRF cross-sections with formulations derived from total intensity of X-rays originating from individual sub-shells that generated a data set for fij's and ωi's of six elements for comparison with available theoretical/empirical/experimental values. Third, from trends of total measured L XRF cross-sections with photon energy for the elements. The results were found affected by the 4f electron filling in the elements.

  17. Investigation of Laser Induced Fluorescence for Concentration Measurements of Diatomic Sulfur.

    Science.gov (United States)

    1981-12-01

    Once the spectrum was obtained, it was calibrated with N2 laser scatter and a mercury reference run. Fluorescence peaks were identified by com... Freddie , Jr. The Measurement of Quenching Rate Constants Using Fluorescence Emission. MS Thesis. Wright-Patterson Air Force Base, Ohio: Air Force Institute

  18. All Fiber-optic Fluorescent Spectral Measurement and Analysis on Alga Chla/c Characteristics

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The fluorescent principle used for measuring alga characteristic parameters and the optimum structure design of the instrument are discussed. The fluorescent spectrum of Chla/c and the time-resolved different spectrum ΔA(λ,t) are given. The research provides an effective method for considering the density and the classification of algae, which will be helpful to monitor sea pollution.

  19. MEASUREMENT OF B(K{sup +} {yields} {pi}{sup +} {nu}{bar {nu}})

    Energy Technology Data Exchange (ETDEWEB)

    KETTELL,S.H.

    2000-05-22

    The experimental measurement of K{sup +} {yields} {pi}{sup +} {nu}{bar {nu}} is reviewed. New results from experiment E787 at BNL are presented: with data from 1995-97 the branching ratio has been measured to be B(K{sup +} {yields} {pi}{sup +} {nu}{bar {nu}}) = (1.5{sub {minus}1.2}{sup +3.4}) x 10{sup {minus}10}. The future prospects for additional data in this mode are examined.

  20. Measurement of 235U Fission Yield Induced by 252Cf Fission Neutron

    Institute of Scientific and Technical Information of China (English)

    YANG; Yi; LIU; Shi-long; JIANG; Wen-gang

    2015-01-01

    We measured fission yields of 235U by 252Cf fission neutrons with the directγray spectrometric method.Square sample foils of 15 mm,abundance of 235U is 90.2%,mass of 0.7gram,covered by pure aluminum foil.After irradiations every sample was measured by HPGe spectrometry for about 2months.Based on 140Ba’s fission yield,we get relative fission yields and the results were shown in Fig.1.

  1. Absolute quantum yield measurements for the formation of oxygen atoms after UV laser excitation of SO2 at 222.4 nm

    Indian Academy of Sciences (India)

    Mohammed Abu-Bajeh; Melanie Cameron; Kyung-Hoon Jung; Christoph Kappel; Almuth Läuter; Kyoung-Seok Lee; Hari P Upadhyaya; Rajesh K Vatsa; Hans-Robert Volpp

    2002-12-01

    The dynamics of formation of oxygen atoms after UV photoexcitation of SO2 in the gas-phase was studied by pulsed laser photolysis-laser-induced fluorescence `pump-and-probe' technique in a flow reactor. SO2 at room-temperature was excited at the KrCl excimer laser wavelength (222.4 nm) and O(3P) photofragments were detected under collision-free conditions by vacuum ultraviolet laser-induced fluorescence. The use of narrow-band probe laser radiation, generated via resonant third-order sum-difference frequency conversion of dye laser radiation in Krypton, allowed the measurement of the nascent O(3P=2,1,0) fine-structure state distribution: =2/=1/=0 = (0.88 ± 0.02)/(0.10 ± 0.01)/(0.02 ± 0.01). Employing NO2 photolysis as a reference, a value of O(3P) = 0.13 ± 0.05 for the absolute O(3P) atom quantum yield was determined. The measured O(3P) quantum yield is compared with the results of earlier fluorescence quantum yield measurements. A suitable mechanism is suggested in which the dissociation proceeds via internal conversion from high rotational states of the initially excited SO2(∼ 1 B2) (1, 2, 2) vibronic level to nearby continuum states of the electronic ground state.

  2. Measurements of the Ultraviolet Fluorescence Cross Sections and Spectra of Bacillus Anthracis Simulants

    Energy Technology Data Exchange (ETDEWEB)

    Stephens, J.R.

    1998-09-01

    Measurements of the ultraviolet autofluorescence spectra and absolute cross sections of the Bacillus anthracis (Ba) simulants Bacillus globigii (Bg), Bacillus megaterium (Bm), Bacillus subtilis (Bs), and Bacillus cereus (Bc) were measured. Fluorescence spectra and cross sections of pine pollen (Pina echinata) were measured for comparison. Both dried vegetative cells and spores separated from the sporulated vegetative material were studied. The spectra were obtained by suspending a small number (<10) of particles in air in our Single Particle Spectroscopy Apparatus (SPSA), illuminating the particles with light from a spectrally filtered arc lamp, and measuring the fluorescence spectra of the particles. The illumination was 280 nm (20 nm FWHM) and the fluorescence spectra was measured between 300 and 450 nm. The fluorescence cross section of vegetative Bg peaks at 320 nm with a maximum cross section of 5 X 10{sup -14} cm{sup 2}/sr-nm-particle while the Bg spore fluorescence peaks at 310 nm with peak fluorescence of 8 X 10{sup -15} cm{sup 2}/sr-nm-particle. Pine pollen particles showed a higher fluorescence peaking at 355 nm with a cross section of 1.7 X 10{sup -13} cm{sup 2}/sr-nm-particle. Integrated cross sections ranged from 3.0 X 10{sup -13} for the Bg spores through 2.25 X 10{sup -12} (cm{sup 2}/sr-particle) for the vegetative cells.

  3. Spatial Variability Analysis of Within-Field Winter Wheat Nitrogen and Grain Quality Using Canopy Fluorescence Sensor Measurements

    Directory of Open Access Journals (Sweden)

    Xiaoyu Song

    2017-03-01

    Full Text Available Wheat grain protein content (GPC is a key component when evaluating wheat nutrition. It is also important to determine wheat GPC before harvest for agricultural and food process enterprises in order to optimize the wheat grading process. Wheat GPC across a field is spatially variable due to the inherent variability of soil properties and position in the landscape. The objectives of this field study were: (i to assess the spatial and temporal variability of wheat nitrogen (N attributes related to the grain quality of winter wheat production through canopy fluorescence sensor measurements; and (ii to examine the influence of spatial variability of soil N and moisture across different growth stages on the wheat grain quality. A geostatistical approach was used to analyze data collected from 110 georeferenced locations. In particular, Ordinary Kriging Analysis (OKA was used to produce maps of wheat GPC, GPC yield, and wheat canopy fluorescence parameters, including simple florescence ratio and Nitrogen Balance Indices (NBI. Soil Nitrate-Nitrogen (NO3-N content and soil Time Domain Reflectometry (TDR value in the study field were also interpolated through the OKA method. The fluorescence parameter maps, soil NO3-N and soil TDR maps obtained from the OKA output were compared with the wheat GPC and GPC yield maps in order to assess their relationships. The results of this study indicate that the NBI spatial variability map in the late stage of wheat growth can be used to distinguish areas that produce higher GPC.

  4. L{sub i} (i=1,2,3) subshell X-ray production cross-sections and fluorescence yields for Ir, Pt, Pb and Bi

    Energy Technology Data Exchange (ETDEWEB)

    Singh, P.; Sharma, M.; Shahi, J.S.; Mehta, D.; Singh, N. E-mail: nsingh@pu.ac.in

    2003-09-01

    The L{sub i} (i=1,2,3) subshell X-ray production (XRP) cross-sections were measured for {sub 77}Ir, {sub 78}Pt, {sub 82}Pb and {sub 83}Bi following direct ionization in the L{sub i} (i=1,2,3) subshells by the 59.54 keV {gamma}-rays and the L{sub 3} subshell by the Br/Rb/Sr/Y K X-rays. The photon sources consisting of an {sup 241}Am source in (i) the direct excitation mode and (ii) the secondary excitation mode together with the KBr/RbNO{sub 3}/SrCO{sub 3} /Y secondary exciter and an Si(Li) detector were used. The L{sub i} (i=1,2,3) subshell fluorescence yields ({omega}{sub i}) for these elements were deduced using the measured XRP cross-sections and the L{sub i} subshell photoionization cross-sections based on the Hartree-Fock-Slater model. The measured {omega}{sub 1} values are found to be higher upto 50% than those based on the relativistic Dirac-Hartree-Slater (RDHS) calculations, while the {omega}{sub 2} and {omega}{sub 3} values exhibit good agreement. The predicted jump in the RDHS based {omega}{sub 1} values from {sub 77}Ir to {sub 78}Pt due to onset of intense L{sub 1}-L{sub 3}M{sub 4} CK transition is not observed.

  5. Measuring the absolute DT neutron yield using the Magnetic Recoil Spectrometer at OMEGA and the NIF

    Energy Technology Data Exchange (ETDEWEB)

    Mackinnon, A; Casey, D; Frenje, J A; Johnson, M G; Seguin, F H; Li, C K; Petrasso, R D; Glebov, V Y; Katz, J; Knauer, J; Meyerhofer, D; Sangster, T; Bionta, R; Bleuel, D; Hachett, S P; Hartouni, E; Lepape, S; Mckernan, M; Moran, M; Yeamans, C

    2012-05-03

    A Magnetic Recoil Spectrometer (MRS) has been installed and extensively used on OMEGA and the National Ignition Facility (NIF) for measurements of the absolute neutron spectrum from inertial confinement fusion (ICF) implosions. From the neutron spectrum measured with the MRS, many critical implosion parameters are determined including the primary DT neutron yield, the ion temperature, and the down-scattered neutron yield. As the MRS detection efficiency is determined from first principles, the absolute DT neutron yield is obtained without cross-calibration to other techniques. The MRS primary DT neutron measurements at OMEGA and the NIF are shown to be in excellent agreement with previously established yield diagnostics on OMEGA, and with the newly commissioned nuclear activation diagnostics on the NIF.

  6. Laser-induced fluorescence measurement of the ion-energy-distribution function in a collisionless reconnection experiment.

    Science.gov (United States)

    Stark, A; Fox, W; Egedal, J; Grulke, O; Klinger, T

    2005-12-02

    Observations in space and laboratory plasmas suggest magnetic reconnection as a mechanism for ion heating and formation of non-Maxwellian ion velocity distribution functions (IVDF). Laser-induced fluorescence measurements of the IVDF parallel to the X line of a periodically driven reconnection experiment are presented. A time-resolved analysis yields the evolution of the IVDF within a reconnection cycle. It is shown that reconnection causes a strong increase of the ion temperature, where the strongest increase is found at the maximum reconnection rate. Monte Carlo simulations demonstrate that ion heating is a consequence of the in-plane electric field that forms around the X line in response to reconnection.

  7. Biliary fluorescent aromatic compounds (FACs) measured by fixed wavelength fluorescence (FF) in several marine fish species from the NW Mediterranean.

    Science.gov (United States)

    Insausti, David; Carrasson, Maite; Maynou, Francesc; Cartes, Joan E; Solé, Montserrat

    2009-11-01

    The fixed wavelength fluoresce (FF) method was used to estimate the levels of fluorescent aromatic compounds (FACs) in the bile of fourteen fish species of commercial and/or ecological interest. Sampling was carried out in the NW Mediterranean at depths ranging from 50 to 1000 m during four seasonal cruises. During the summer sampling period, some species were also collected from another site (Vilanova fishing grounds) for comparison. Baseline levels of the polycyclic aromatic hydrocarbons (PAHs) naphthalene, phenanthrene, pyrene and benzo[a]pyrene were measured. Some seasonality was observed, with reduced FF levels in summer and no differences among sites, consistent with sediment PAH levels. We discuss our results in relation to fish phylogeny, season, depth, diet, trophic level and swimming capacity. Overall FF levels indicated differences among species; the suprabenthic feeders from shallow and deep communities, and Mullus barbatus in particular, displayed elevated FF values and are potential candidates for additional monitoring studies.

  8. Micro-light guides: a new method for measuring tissue fluorescence and reflectance.

    Science.gov (United States)

    Ji, S; Chance, B; Nishiki, K; Smith, T; Rich, T

    1979-03-01

    Three-way light guides containing one or more strands of 25-micron or 80-micron diameter optical fibers in each channel have been constructed and used to measure the NADH fluorescence and UV reflectance from mitochondrial suspensions, the perfused, hemoglobin-free rat liver, and the perfused beating interventricular septum of the rabbit. The optical changes measured with these so-called micro-light guides, which have channels containing one or several strands of optical fibers less than 100 micron, are comparable in magnitude with those measured using much larger conventional light guides. The effect of light scattering on the fluorescence channel has been determined and an empirical equation for correcting the fluorescence channel for light scattering has been obtained for mitochondrial suspensions. A mathematical equation characterizing the optical behavior of a two-way micro-light guide has been derived and has been shown to account satisfactorily for reflectance and fluorescence measurements of a mat surface in air.

  9. Platinum plasmonic nanostructure arrays for massively parallel single-molecule detection based on enhanced fluorescence measurements.

    Science.gov (United States)

    Saito, Toshiro; Takahashi, Satoshi; Obara, Takayuki; Itabashi, Naoshi; Imai, Kazumichi

    2011-11-04

    We fabricated platinum bowtie nanostructure arrays producing fluorescence enhancement and evaluated their performance using two-photon photoluminescence and single-molecule fluorescence measurements. A comprehensive selection of suitable materials was explored by electromagnetic simulation and Pt was chosen as the plasmonic material for visible light excitation near 500 nm, which is preferable for multicolor dye-labeling applications like DNA sequencing. The observation of bright photoluminescence (λ = 500-600 nm) from each Pt nanostructure, induced by irradiation at 800 nm with a femtosecond laser pulse, clearly indicates that a highly enhanced local field is created near the Pt nanostructure. The attachment of a single dye molecule was attempted between the Pt triangles of each nanostructure by using selective immobilization chemistry. The fluorescence intensities of the single dye molecule localized on the nanostructures were measured. A highly enhanced fluorescence, which was increased by a factor of 30, was observed. The two-photon photoluminescence intensity and fluorescence intensity showed qualitatively consistent gap size dependence. However, the average fluorescence enhancement factor was rather repressed even in the nanostructure with the smallest gap size compared to the large growth of photoluminescence. The variation of the position of the dye molecule attached to the nanostructure may influence the wide distribution of the fluorescence enhancement factor and cause the rather small average value of the fluorescence enhancement factor.

  10. Simulation of fluorescent measurements in the human skin

    Science.gov (United States)

    Meglinski, Igor V.; Sinichkin, Yurii P.; Utz, Sergei R.; Pilipenko, Helena A.

    1995-05-01

    Reflectance and fluorescence spectroscopy are successfully used for skin disease diagnostics. Human skin optical parameters are defined by its turbid, scattering properties with nonuniform absorption and fluorescence chromophores distribution, its multilayered structure, and variability under different physiological and pathological conditions. Theoretical modeling of light propagation in skin could improve the understanding of these condition and may be useful in the interpretation of in vivo reflectance and autofluorescence (AF) spectra. Laser application in medical optical tomography, tissue spectroscopy, and phototherapy stimulates the development of optical and mathematical light-tissue interaction models allowing to account the specific features of laser beam and tissue inhomogeneities. This paper presents the version of a Monte Carlo method for simulating of optical radiation propagation in biotissue and highly scattering media, allowing for 3D geometry of a medium. The simulation is based on use of Green's function of medium response to single external pulse. The process of radiation propagation is studied in the area with given boundary conditions, taking into account the processes of reflection and refraction at the boundaries of layers inside the medium under study. Results of Monte Carlo simulation were compared with experimental investigations and demonstrated good agreement.

  11. Tools and techniques to measure mitophagy using fluorescence microscopy.

    Science.gov (United States)

    Dolman, Nick J; Chambers, Kevin M; Mandavilli, Bhaskar; Batchelor, Robert H; Janes, Michael S

    2013-11-01

    Mitophagy is a specialized form of autophagy that removes damaged mitochondria, thereby maintaining efficient cellular metabolism and reducing cellular stress caused by aberrant oxidative bursts. Deficits in mitophagy underlie several diseases, and a substantial body of research has elucidated key steps in the pathways that lead to and execute autophagic clearance of mitochondria. Many of these studies employ fluorescence microscopy to visualize mitochondrial morphology, mass, and functional state. Studies in this area also examine colocalization/recruitment of accessory factors, components of the autophagic machinery and signaling molecules to mitochondria. In this review, we provide a brief summary of the current understanding about the processes involved in mitophagy followed by a discussion of probes commonly employed and important considerations of the methodologies to study and analyze mitophagy using fluorescence microscopy. Representative data, where appropriate, are provided to highlight the use of key probes to monitor mitophagy. The review will conclude with a consideration of new possibilities for mitophagy research and a discussion of recently developed technologies for this emerging area of cell biology.

  12. Measuring reactive oxygen and nitrogen species with fluorescent probes: challenges and limitations

    Science.gov (United States)

    Kalyanaraman, Balaraman; Darley-Usmar, Victor; Davies, Kelvin J.A.; Dennery, Phyllis A.; Forman, Henry Jay; Grisham, Matthew B.; Mann, Giovanni E.; Moore, Kevin; Roberts, L. Jackson; Ischiropoulos, Harry

    2013-01-01

    The purpose of this position paper is to present a critical analysis of the challenges and limitations of the most widely used fluorescent probes for detecting and measuring reactive oxygen and nitrogen species. Where feasible, we have made recommendations for the use of alternate probes and appropriate analytical techniques that measure the specific products formed from the reactions between fluorescent probes and reactive oxygen and nitrogen species. We have proposed guidelines that will help present and future researchers with regard to the optimal use of selected fluorescent probes and interpretation of results. PMID:22027063

  13. Experimental study of multi-photon contamination on the measurement of fluorescent decay time

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In the measurement of fluorescent lifetime based on time correlation-single photon counting technique by means of TAC, due to the contamination of multi-photons a deviation of fluorescent lifetime measured from the expected value is experimentally studied. A correction function instead of a simple exponential function is used to fit the experiment data. The validation of the correction function is checked using the experimental data of several test samples: YAP, NaI(T1) and LSO. The results show that the correction function well fits the data and the reasonable fluorescent lifetimes are obtained.

  14. Measurement of the branching for the decay K{sub s} {yields} {pi} e{upsilon}

    Energy Technology Data Exchange (ETDEWEB)

    Aloisio, A.; Ambrosino, F.; Cevenini, F.; Di Donato, C.; Doria, A.; Merola, L.; Pirozzi, G.; Saracino, G.; Chiefari, G. [Naples Univ. Federico 2., Naples (Italy). Dipt. di Scienze Fisiche]|[Istituto Nazionale di Fisica Nucleare, Naples (Italy); Antonelli, A.; Antonelli, M.; Bencivenni, G.; Bertolucci, S.; Bloise, C.; Bossi, F.; Campana, P.; Capon, G.; Ciambrone, P.; De Sangro, R.; De Simone, P.; Dell' Agnelo, S.; Denig, A.; Dreucci, M.; Felici, G.; Ferrer, M.L.; Finocchiaro, G.; Franceschi, A.; Giovannella, S.; Lanfranchi, G.; Mei, W.; Miscetti, S.; Murtas, F.; Passalacqua, L.; Sfilogi, I.; Moulson, M.; Valente, P.; Santangelo, P. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati, Rome (Italy); Bacci, C.; Branchini, P.; Ceradini, F.; Farilla, A.; Graziani, E.; Palutan, M.; Nguyen, F.; Passeri, A.; Tortora, L.; Spiriti, E. [Rome Univ. 3., Rome (Italy). Dipt. di Fisica]|[Istituto Nazionale di Fisica Nucleare, Rome (Italy); Andryakov, A. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati, Rome (Italy)]|[Institute for Theoretical and Experimental Physics, Moscow (Russian Federation); Bini, C.; Bocci, V.; Cabibbo, G.; Caloi, R.; De Lucia, E.; De Zorzi, G.; Di Domenico, A.; Franzini, P.; Gauzzi, P.; Lacava, F.; Leone, D.; Pasqualucci, E.; Petrolo, E.; Picca, D.; Pontecorvo, L.; Spadaro, T.; Sciascia, B.; Veneziano, S. [Rome Univ. La Sapienza, Rome (Italy). Dipt. di Fisica]|[Istituto Nazionale di Fisica Nucleare, Rome (Italy); Han, S.W.; Lu, F.; Tong, G.L.; Xu, Y.; Yu, Y. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati, Rome (Italy)]|[Institute for High Energy Physics, Beijing (China); Lee-Franzini, J. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati, Rome (Italy)]|[State University of New York at Stony Brook, Physics Department, New York (United States); Matsyuk, M.; Nedosekin, A. [and others

    2002-03-01

    It is presented a measurement of the branching ratio BR (K {yields} {pi}{sup {+-}} e {+-}v(v)) performed using the KLOW detector. K{sub s}-mesons are produced in the reaction e{sup {+-}}e{sup {+-}} {yields} {phi} {yields} K{sub S}K{sub L} at the DA{phi}NE collider. In a sample of {approx} 5 x 10{sup 6} K{sub s}tagged events it is found 624 {+-} 30 semileptonic K{sub s} decays. Normalizing to the K{sub s} {yields} {pi}{sup +} {pi}{sup -} count in the same data sample, it is obtained BR (K{sub s} {yields} {pi} e {upsilon}) = (6.91 {+-} 0.37) x 10{sup -}4, in agreement with the Standard Model expectation.

  15. Nanometer-resolution depth-resolved measurement of florescence-yield soft x-ray absorption spectroscopy for FeCo thin film

    Science.gov (United States)

    Sakamaki, M.; Amemiya, K.

    2017-08-01

    We develop a fluorescence-yield depth-resolved soft x-ray absorption spectroscopy (XAS) technique, which is based on the principle that the probing depth is changed by the emission angle of the fluorescence soft x rays. Compared with the electron-yield depth-resolved XAS technique, which has been established in this decade, we can observe wider range in-depth XAS distribution up to several tens of nm. Applying this technique to a 30 ML (˜4.3 nm) FeCo thin film, we observe Fe L-edge XAS spectra at the probing depth of 0.3-6 nm and find that the film has 22 ML (˜3.1 nm) surface oxide layer while its inner layer shows metallic state. We thus successfully obtain nanometer-resolution depth-resolved XAS spectra and further expect that operando measurement under the electric and/or magnetic fields is possible.

  16. Effect of Seed Inoculation with Pseudomonas fluorescence and Glomus esculentum on Quantitative and Qualitative Yield ofTwo Forage Corn Cultivars

    Directory of Open Access Journals (Sweden)

    M. Pourebrahimi

    2014-02-01

    Full Text Available In order to investigate the effect of Pseudomonas fluorescence strain 93 bacteria and Glomus esculentum fungus on quantitative and qualitative yield of two forage corn cultivars, an RCBD based factorial field experiment with three replications was conducted at the Agricultural Research Station of the University of Guilan in 2008. Treatments were considered as phosphorus chemical fertilizer, seed inoculation with Glomus esculentum mycorrhiza fungus, seed inoculation with Pseudomonas fluorescence strain 93 bacteria, seed inoculation with Pseudomonas fluorescence strain 93 bacteria and Glomus esculentum mycorrhiza fungus, and two corn cultivars (SC704 and SC647. No application of chemical fertilizer and microorganisms was considered as control. Results of ANOVA showed that plant height and leaf area, plant SPAD value, and plant biological yield were affected by cultivar × fertilizer interaction, significantly. The highest plant height (249.30 cm, SPAD value (52.30, and biological yield (251.51 g/plant were related to cultivar SC704 which treated with chemical phosphorous fertilizer or inoculated with bacteria-fungus combination. The maximum plant leaf area was achieved in chemical phosphorous fertilizer followed by application of both bacteria and fungus treatments. Inoculation with both bacteria and fungus also resulted to highest dry matter digestibility (77.37 % and crude protein (12.61 %. However, the highest (54.41 % and lowest (34.38 % crude fiber was related to control and bacteria-fungus combination treatments, respectively. Among two cultivars used in the experiment, SC704 was superior according to examine crop traits. Therefore, it could be expected that inoculating the seeds of SC704 corn cultivar with Pseudomonas fluorescence- Glomus esculentum combination resulted to reduce the use of phosphorus fertilizers and increase in the quality and quantity of forage corn.

  17. Modulation of the fluorescence yield in heliobacterial cells by induction of charge recombination in the photosynthetic reaction center.

    Science.gov (United States)

    Redding, Kevin E; Sarrou, Iosifina; Rappaport, Fabrice; Santabarbara, Stefano; Lin, Su; Reifschneider, Kiera T

    2014-05-01

    Heliobacteria contain a very simple photosynthetic apparatus, consisting of a homodimeric type I reaction center (RC) without a peripheral antenna system and using the unique pigment bacteriochlorophyll (BChl) g. They are thought to use a light-driven cyclic electron transport pathway to pump protons, and thereby phosphorylate ADP, although some of the details of this cycle are yet to be worked out. We previously reported that the fluorescence emission from the heliobacterial RC in vivo was increased by exposure to actinic light, although this variable fluorescence phenomenon exhibited very different characteristics to that in oxygenic phototrophs (Collins et al. 2010). Here, we describe the underlying mechanism behind the variable fluorescence in heliobacterial cells. We find that the ability to stably photobleach P800, the primary donor of the RC, using brief flashes is inversely correlated to the variable fluorescence. Using pump-probe spectroscopy in the nanosecond timescale, we found that illumination of cells with bright light for a few seconds put them in a state in which a significant fraction of the RCs underwent charge recombination from P800 (+)A0 (-) with a time constant of ~20 ns. The fraction of RCs in the rapidly back-reacting state correlated very well with the variable fluorescence, indicating that nearly all of the increase in fluorescence could be explained by charge recombination of P800 (+)A0 (-), some of which regenerated the singlet excited state. This hypothesis was tested directly by time-resolved fluorescence studies in the ps and ns timescales. The major decay component in whole cells had a 20-ps decay time, representing trapping by the RC. Treatment of cells with dithionite resulted in the appearance of a ~18-ns decay component, which accounted for ~0.6 % of the decay, but was almost undetectable in the untreated cells. We conclude that strong illumination of heliobacterial cells can result in saturation of the electron acceptor pool

  18. [The analysis of sinusoidal modulated method used for measuring fluorescence lifetime].

    Science.gov (United States)

    Feng, Ying; Huang, Shi-hua

    2007-12-01

    This paper has built a system with a sinusoidal modulated LED as the excitation source. Such exciter was used upon the sample Eu2 L'3 x nH2O (L' = C4H4O4). Both the excitation light and the 5Do-7F2 emission of Eu3+ ion were measured. Fluorescence lifetime, which approximate to 0.680 ms, can then be obtained from the measured excitation and fluorescence waveforms by non-linear least square curve fitting based on the principle of phase-shift measurement of fluorescence lifetime. Data processing methods considering respectively the high order harmonics in the modulation and multi-exponential decay of the fluorescence were discussed. A method of utilizing Fourier series expandedness to amendatory the result was put forward. Accordingly, the applicability for phase-shift method was expanded as well as a more exact result was acquired.

  19. Fast repetition rate (FRR) fluorometry: variability of chlorophyll a fluorescence yields in colonies of the corals, Montastraea faveolata (w.) and Diploria labyrinthiformes (h.) recovering from bleaching.

    Science.gov (United States)

    Lombardi; Lesser; Gorbunov

    2000-09-05

    Recently, an underwater version of a fast repetition rate fluorometer (FRRF) was developed for the non-destructive study of fluorescence yields in benthic photoautotrophs. We used an FRRF to study bleached colonies of the corals, Montastraea faveolata and Diploria labyrinthiformes at sites surrounding Lee Stocking Island, Exuma, Bahamas, to assess their recovery from bleaching ( approximately 1 year after the initial bleaching event) induced by elevated temperatures. The steady state quantum yields of chlorophyll a fluorescence (DeltaF'/F'(m)) from photosystem II (PSII) within coral colonies were separated into three categories representing visibly distinct degrees of bleaching ranging from no bleaching to completely bleached areas. Differences in DeltaF'/F'(m) were significantly different from bleached to unbleached regions within colonies. Dark, unbleached regions within colonies exhibited significantly higher DeltaF'/F'(m) values (0.438+/-0.019; mean+/-S.D.) when compared to lighter regions, and occupied a majority of the colonies' surface area (46-73%). Bleached regions exhibited significantly lower DeltaF'/F'(m) (0.337+/-0.014) and covered only 7-25% of the colonies' surface area. The observations from this study suggest that zooxanthellae in bleached regions of a colony exhibit reduced photosynthetic activity as long as one year after a bleaching event and that in situ fluorescence techniques such as FRRF are an effective means of studying coral responses and recovery from natural or anthropogenic stress in a non-destructive manner.

  20. Syntheses of Some Organic Fluorescent Dyes for Security Tickers

    Institute of Scientific and Technical Information of China (English)

    LI Jun-fen; BAI Guan; LIN Pei-hua; TIAN Mei-lin; DONG Chuan; LI Du-xin

    2004-01-01

    Five organic fluorescence dyes were synthesized by two- or three-step reactions. These synthetic methods have an advantage of the simple processes, low costs and high yields. The compositions of the five compounds are characterized by IR, 1H NMR, elemental analyses and fluorescence spectroscopies. The quantum yields of fluorescence were measured.

  1. DAPI-fluorescent fading: a problem in microscopy or a way to measure nuclear DNA content?

    Science.gov (United States)

    Gallardo-Escárate, Cristian; Álvarez-Borrego, Josué; Kober, V.; del Río-Portilla, Miguel Á.

    2006-01-01

    In observation by confocal or conventional fluorescence microscopy, the retardation of the lost in fluorescence, from highest signal of fluorescence to lowest intensity are important factors in order to obtain accurate images. This problem is very common in fluorochromes for nuclear DNA and especially for DAPI stain. The fluorescence of DAPI is rapidly lost when it is exposure to excitation by ultra violet (UV) light, and especially under optimal condition of observation. Although the fading process could be retardate by using of mounting medium with antifading solutions, the photochemical process underlying the fluorescence decay has not yet been fully explained. In addiction, neither relationship has been tested between the fluorescence fading and nuclear DNA content. However, the capacity of the DNA to absorb UV light is knows. In order to test this relationship we measured by means of image analysis the fluorescence intensity in several nuclei types during a fading period. The analysis was performed by an algorithm specifically built in MATLAB software. The relationship between nuclear DNA content and DAPI-fluorescence fading was found equal to 99%. This study demonstrates the feasibility for estimates genome size by quantification of fluorescence fading. In this context, the present method allows to measure nuclear DNA content in several medical applications (cancer, HIV, organ transplants, etc). Nowadays, for measuring DNA content, flow cytometry is widely used; however, with the flow cytometry method it is not possible to select a specific group of cells, such as from a specific region of a tumor. Moreover, the using of image analysis allows automatizing diagnostics procedures.

  2. Standardization and quality assurance in fluorescence measurements I state-of-the art and future challenges

    CERN Document Server

    Resch-Genger, Ute

    2008-01-01

    The validation and standardization of fluorescence methods is still in its infancy as compared to other prominent analytical and bioanalytical methods. Appropriate quality assurance standards are however a prerequisite for applications in highly regulated fields such as medical diagnostics, drug development, or food analysis. For the first time, a team of recognized international experts has documented the present status of quality assurance in fluorescence measurements, and outlines concepts for establishing standards in this field. This first of two volumes covers basic aspects and various techniques such as steady-state and time-resolved fluorometry, polarization techniques, and fluorescent chemical sensors

  3. Chlorophyll fluorescence in vivo as a probe for rapid measurement of tolerance to ultraviolet radiation

    Energy Technology Data Exchange (ETDEWEB)

    Smillie, R.M. (Macquarie Univ., North Ryde (Australia). School of Biological Sciences)

    1983-02-01

    Chlorophyll fluorescence in vivo was progressively lost in pea leaves irradiated with either short or long-wave light. The changes were consistent with the development in the intact leaves of an inhibitory site on the photooxidizing side of photosystem II. In contrast, leaves of two species of Agave, plants regarded as more resistant to UV radiation, showed only minor changes in chlorophyll fluorescence. Agave americana was affected less than A. attenuata. The application of measurements of chlorophyll fluorescence in vivo to screening for tolerance to UV radiation is discussed.

  4. A non-Gaussian distribution quantifies distances measured with fluorescence localization techniques

    DEFF Research Database (Denmark)

    Churchman, L.S.; Flyvbjerg, H.; Spudich, J.A.

    2006-01-01

    When single-molecule fluorescence localization techniques are pushed to their lower limits in attempts to measure ever-shorter distances, measurement errors become important to understand. Here we describe the non-Gaussian distribution of measured distances that is the key to proper interpretation...

  5. Handheld Device Adapted to Smartphone Cameras for the Measurement of Sodium Ion Concentrations at Saliva-Relevant Levels via Fluorescence

    Directory of Open Access Journals (Sweden)

    Michelle Lipowicz

    2015-06-01

    Full Text Available The use of saliva sampling as a minimally-invasive means for drug testing and monitoring physiology is a subject of great interest to researchers and clinicians. This study describes a new optical method based on non-axially symmetric focusing of light using an oblate spheroid sample chamber. The device is simple, lightweight, low cost and is easily attached to several different brands/models of smartphones (Apple, Samsung, HTC and Nokia for the measurement of sodium ion levels at physiologically-relevant saliva concentrations. The sample and fluorescent reagent solutions are placed in a specially-designed, lightweight device that excludes ambient light and concentrates 470-nm excitation light, from a low-power photodiode, within the sample through non-axially-symmetric refraction. The study found that smartphone cameras and post-image processing quantitated sodium ion concentration in water over the range of 0.5–10 mM, yielding best-fit regressions of the data that agree well with a data regression of microplate luminometer results. The data suggest that fluorescence can be used for the measurement of salivary sodium ion concentrations in low-resource or point-of-care settings. With further fluorescent assay testing, the device may find application in a variety of enzymatic or chemical assays.

  6. Response of grapevine leaves to Plasmopara viticola infection by means of measurement of reflectance and fluorescence signals

    Directory of Open Access Journals (Sweden)

    David Šebela

    2012-01-01

    Full Text Available Response of grapevine leaf tissue naturally infected by Plasmopara viticola in field was measured by means of chlorophyll fluorescence and reflectance signals. Three susceptible grapevine varieties (Cabernet Sauvignon, Pinot Blanc and Pinot Gris were used in this study. Since the infection impairs photosynthetic activity, distribution of FV/FM parameter (maximum quantum yield of Photosystem II over the leaf was effective to discriminate healthy and naturally infected leaf tissue. FV/FM was reduced ~ 25% in all infected leaf parts. Infected leaf spots expressed significantly altered chlorophyll fluorescence induction kinetics expressing much slower electron transport rate both on donor and acceptor site of PSII. Vegetation reflectance indices followed the variations in pigment content after the fungal infection. R750/R700 (R2 = 0.877 and CRI (carotenoid reflectance index; R2 = 0.735 were the most potent to follow changes in chlorophylls and carotenoids contents, respectively. Infected leaf tissue exhibited decrease in chlorophyll a (~50 % as well as carotenoids (~70%. We conclude that combination of chlorophyll fluorescence and reflectance measurements can be used as an effective non-invasive tool for an early detection of Plasmopara viticola in field as well as for estimation of the level of infection.

  7. Perturbation of planarity as the possible mechanism of solvent-dependent variations of fluorescence quantum yield in 2-aryl-3-hydroxychromones

    Science.gov (United States)

    Klymchenko, Andrey S.; Pivovarenko, Vasyl G.; Demchenko, Alexander P.

    2003-03-01

    In order to understand the unexpectedly low quantum yields of 3-hydroxyflavones (3-HFs) in certain solvents, such as acetonitrile or ethyl acetate, the comparative study of solvent-dependent properties of parent 3-HF, 2-furyl-3-hydroxychromone and 2-benzofuryl-3-hydroxychromone derivatives have been performed. The results suggest that the formation of intermolecular hydrogen bond of 3-hydroxy group with the solvent favors non-planar conformations of phenyl group with respect to chromone system. This steric hindrance is not observed in the case of furan- and benzofuran-substituted 3-hydroxychromones (3-HCs). These results suggesting a new strategy for dramatic improvement of fluorescence properties of 3-HCs as two-wavelength ratiometric fluorescence probes.

  8. Model based analysis of transient fluorescence yield induced by actinic laser flashes in spinach leaves and cells of green alga Chlorella pyrenoidosa Chick.

    Science.gov (United States)

    Belyaeva, N E; Schmitt, F-J; Paschenko, V Z; Riznichenko, G Yu; Rubin, A B; Renger, G

    2014-04-01

    Measurements of Single Flash Induced Transient Fluorescence Yield (SFITFY) on spinach leaves and whole cells of green thermophilic alga Chlorella pyrenoidosa Chick were analyzed for electron transfer (ET) steps and coupled proton transfer (PT) on both the donor and the acceptor side of the reaction center (RC) of photosystem II (PS II). A specially developed PS II model (Belyaeva et al., 2008, 2011a) allowed the determination of ET steps that occur in a hierarchically ordered time scale from nanoseconds to several seconds. Our study demonstrates that our SFITFY data is consistent with the concept of the reduction of P680(+) by YZ in both leaves and algae (studied on spinach leaves and cells of Chlorella pyrenoidosa Chick). The multiphasic P680(+) reduction kinetics by YZ in PS II core complexes with high oxygen evolution capacity was seen in both algae and leaves. Model simulation to fit SFITFY curves for dark adapted species used here gives the rate constants to verify nanosecond kinetic stages of P680(+) reduction by YZ in the redox state S1 of the water oxidizing complex (WOC) shown in Kühn et al. (2004). Then a sequence of relaxation steps in the redox state S1, outlined by Renger (2012), occurs in both algae and leaves as a similar non-adiabatic ET reactions. Coupled PT is discussed briefly to understand a rearrangement of hydrogen bond protons in the protein matrix of the WOC (Umena et al., 2011). On the other hand, present studies showed a slower reoxidation of reduced QA by QB in algal cells as compared with that in a leaf that might be regarded as a consequence of differences of spatial domains at the QB-site in leaves compared to algae. Our comparative study helped to correlate theory with experimental data for molecular photosynthetic mechanisms in thylakoid membranes. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  9. A Spectrometric Setup for Synchronous Total Internal Reflection Fluorescence Measurement at the Solid/Liquid Interface

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A spectrometric setup to perform total internal reflection fluorescence (TIRF) and synchronous TIRF measurements at solid/liquid interfaces is presented. The combination of TIRF and synchronous fluorescence was proposed to analyze simultaneously different components at interfaces. The TIRF excitation, emission and synchronous spectra of a water-soluble porphyrin were obtained from water/glass interface using this setup without the existence of a surfactant.

  10. Dynamic measurement of fluorescent proteins spectral distribution on virus infected cells

    Science.gov (United States)

    Lee, Ja-Yun; Wu, Ming-Xiu; Kao, Chia-Yun; Wu, Tzong-Yuan; Hsu, I.-Jen

    2006-09-01

    We constructed a dynamic spectroscopy system that can simultaneously measure the intensity and spectral distributions of samples with multi-fluorophores in a single scan. The system was used to monitor the fluorescence distribution of cells infected by the virus, which is constructed by a recombinant baculoviruses, vAcD-Rhir-E, containing the red and green fluorescent protein gene that can simultaneously produce dual fluorescence in recombinant virus-infected Spodoptera frugiperda 21 cells (Sf21) under the control of a polyhedrin promoter. The system was composed of an excitation light source, a scanning system and a spectrometer. We also developed an algorithm and fitting process to analyze the pattern of fluorescence distribution of the dual fluorescence produced in the recombinant virus-infected cells. All the algorithm and calculation are automatically processed in a visualized scanning program and can monitor the specific region of sample by calculating its intensity distribution. The spectral measurement of each pixel was performed at millisecond range and the two dimensional distribution of full spectrum was recorded within several seconds. We have constructed a dynamic spectroscopy system to monitor the process of virus-infection of cells. The distributions of the dual fluorescence were simultaneously measured at micrometer resolution.

  11. Spectrally resolved fluorescence lifetime imaging of Nile red for measurements of intracellular polarity

    Science.gov (United States)

    Levitt, James A.; Chung, Pei-Hua; Suhling, Klaus

    2015-09-01

    Spectrally resolved confocal microscopy and fluorescence lifetime imaging have been used to measure the polarity of lipid-rich regions in living HeLa cells stained with Nile red. The emission peak from the solvatochromic dye in lipid droplets is at a shorter wavelength than other, more polar, stained internal membranes, and this is indicative of a low polarity environment. We estimate that the dielectric constant, ɛ, is around 5 in lipid droplets and 25<ɛ<40 in other lipid-rich regions. Our spectrally resolved fluorescence lifetime imaging microscopy (FLIM) data show that intracellular Nile red exhibits complex, multiexponential fluorescence decays due to emission from a short lifetime locally excited state and a longer lifetime intramolecular charge transfer state. We measure an increase in the average fluorescence lifetime of the dye with increasing emission wavelength, as shown using phasor plots of the FLIM data. We also show using these phasor plots that the shortest lifetime decay components arise from lipid droplets. Thus, fluorescence lifetime is a viable contrast parameter for distinguishing lipid droplets from other stained lipid-rich regions. Finally, we discuss the FLIM of Nile red as a method for simultaneously mapping both polarity and relative viscosity based on fluorescence lifetime measurements.

  12. Forage quality and composition measurements as predictors of ethanol yield from maize (Zea mays L.) stover.

    Science.gov (United States)

    Lorenz, Aaron J; Anex, Rob P; Isci, Asli; Coors, James G; de Leon, Natalia; Weimer, Paul J

    2009-03-09

    Improvement of biofeedstock quality for cellulosic ethanol production will be facilitated by inexpensive and rapid methods of evaluation, such as those already employed in the field of ruminant nutrition. Our objective was to evaluate whether forage quality and compositional measurements could be used to estimate ethanol yield of maize stover as measured by a simplified pretreatment and simultaneous saccharification and fermentation assay. Twelve maize varieties selected to be diverse for stover digestibility and composition were evaluated. Variation in ethanol yield was driven by glucan convertibility rather than by glucan content. Convertibility was highly correlated with ruminal digestibility and lignin content. There was no relationship between structural carbohydrate content (glucan and neutral detergent fiber) and ethanol yield. However, when these variables were included in multiple regression equations including convertibility or neutral detergent fiber digestibility, their partial regression coefficients were significant and positive. A regression model including both neutral detergent fiber and its ruminal digestibility explained 95% of the variation in ethanol yield. Forage quality and composition measurements may be used to predict cellulosic ethanol yield to guide biofeedstock improvement through agronomic research and plant breeding.

  13. Forage quality and composition measurements as predictors of ethanol yield from maize (Zea mays L. stover

    Directory of Open Access Journals (Sweden)

    de Leon Natalia

    2009-03-01

    Full Text Available Abstract Background Improvement of biofeedstock quality for cellulosic ethanol production will be facilitated by inexpensive and rapid methods of evaluation, such as those already employed in the field of ruminant nutrition. Our objective was to evaluate whether forage quality and compositional measurements could be used to estimate ethanol yield of maize stover as measured by a simplified pretreatment and simultaneous saccharification and fermentation assay. Twelve maize varieties selected to be diverse for stover digestibility and composition were evaluated. Results Variation in ethanol yield was driven by glucan convertibility rather than by glucan content. Convertibility was highly correlated with ruminal digestibility and lignin content. There was no relationship between structural carbohydrate content (glucan and neutral detergent fiber and ethanol yield. However, when these variables were included in multiple regression equations including convertibility or neutral detergent fiber digestibility, their partial regression coefficients were significant and positive. A regression model including both neutral detergent fiber and its ruminal digestibility explained 95% of the variation in ethanol yield. Conclusion Forage quality and composition measurements may be used to predict cellulosic ethanol yield to guide biofeedstock improvement through agronomic research and plant breeding.

  14. Introduction of an electron push-pull system yields a planar Red Kaede fluorescence protein chromophore analogue stabilized by a C = O… interaction

    Indian Academy of Sciences (India)

    Ashish Singh; Basanta Kumar Rajbongshi; Gurunath Ramanathan

    2015-05-01

    Crystal structures of four red kaede fluorescence protein chromophore analogues are reported here. Molecules I-III adopt a non-planar geometry stabilized by … stacking and hydrogen bonding. Introduction of an electron push-pull system induces molecule IV to be planar and a C = O… supramolecular interaction is observed as well. Strong electron withdrawing and donating groups also ensure formation of a higher order two and three dimensional supramolecular architecture through hydrogen bonds in molecules I and IV. All the analogues exhibit good photoluminescence properties and emit in the red region with excellent quantum yields.

  15. 233U mass yield measurements around and within the symmetry region with the ILL Lohengrin spectrometer

    Directory of Open Access Journals (Sweden)

    Chebboubi A.

    2016-01-01

    Full Text Available The study of fission yields has a major impact on the characterization and understanding of the fission process and is mandatory for reactor applications. The LPSC in collaboration with ILL and CEA has developed a measurement program on fission fragment distributions at the Lohengrin spectrometer of the ILL, with a special focus on the masses constituting the heavy peak. We will present in this paper our measurement of the very low fission yields in the symmetry mass region and the heavy mass wing of the distribution for 233U thermal neutron induced fission. The difficulty due to the strong contamination by other masses with much higher yields will be addressed in the form of a new analysis method featuring the required contaminant correction. The apparition of structures in the kinetic energy distributions and possible interpretations will be discussed, such as a possible evidence of fission modes.

  16. 233U mass yield measurements around and within the symmetry region with the ILL Lohengrin spectrometer

    Science.gov (United States)

    Chebboubi, A.; Kessedjian, G.; Sage, C.; Bernard, D.; Blanc, A.; Faust, H.; Köster, U.; Litaize, O.; Mutti, P.; Serot, O.

    2016-03-01

    The study of fission yields has a major impact on the characterization and understanding of the fission process and is mandatory for reactor applications. The LPSC in collaboration with ILL and CEA has developed a measurement program on fission fragment distributions at the Lohengrin spectrometer of the ILL, with a special focus on the masses constituting the heavy peak. We will present in this paper our measurement of the very low fission yields in the symmetry mass region and the heavy mass wing of the distribution for 233U thermal neutron induced fission. The difficulty due to the strong contamination by other masses with much higher yields will be addressed in the form of a new analysis method featuring the required contaminant correction. The apparition of structures in the kinetic energy distributions and possible interpretations will be discussed, such as a possible evidence of fission modes.

  17. A laser-induced fluorescence measurement technique for obtaining neutral hydrogen densities in plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Yao, X.Z.; Yang, T.F.; Chang-Diaz, F.R. [Plasma Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    1995-09-01

    The resonance fluorescence of neutral hydrogen illuminated by {ital H}{sub {alpha}} radiation has been used as a technique for the spatially and temporally resolved density measurements of neutral hydrogen in high temperature plasmas, such as in the tokamak and magnetic mirror plasma fusion devices. The fluorescence signal, usually very weak and buried in the background of stray laser light and {ital H}{sub {alpha}} emission, is very difficult to extract and its measurements are inaccurate. This paper discusses the improvement of the signal extraction using two optical path laser-induced fluorescence (LIF) methods. One optical path carries the fluorescence signal and the background (the stray laser light and {ital H}{sub {alpha}} emission), whereas the other path carries only the background signal. By combining these two signals, a clean fluorescence signal can be isolated by subtracting out the background using a differential amplifier. The measurement is obtained instantaneously from these two signals which are taken simultaneously in one pulse rather than being extracted from two separate spectra taken in two sequential pulses (double pulses). This method, therefore, makes a significant improvement on the double pulse technique in terms of the accuracy of the measurement and the time resolution. Using this LIF technique the measurement of the neutral density profile in the exhaust of a tandem mirror plasma propulsion device is obtained and presented. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

  18. Fluorescence Spectrum and Decay Measurement for Hsil VS Normal Cytology Differentiation in Liquid Pap Smear Supernatant

    Science.gov (United States)

    Vaitkuviene, A.; Gegzna, V.; Juodkazis, S.; Jursenas, S.; Miasojedovas, S.; Kurtinaitiene, R.; Rimiene, J.; Vaitkus, J.

    2009-06-01

    Cervical smear material contains endo and exocervical cells, mucus and inflammative, immune cells in cases of pathology. Just not destroyed keratinocytes lay on the glass for microscopy. Liquid cytology supernatant apart other diagnostics could be used for photodiagnostic. The spectroscopic parameters suitable for Normal and HSIL cytology groups supernatant differentiation are demonstrated. The dried liquid PAP supernatant fractions—sediment and liquid were investigated. Excitation and emission matrices (EEM), supernatant fluorescence decay measured under 280 nm diode short pulse excitation and fluorescence spectroscopy by excitation with 355 nm laser light were analyzed. The differences between Normal and HSIL groups were statistically proven in the certain spectral regions. Fluorescence decay peculiarities show spectral regions consisting of few fluorophores. Obtained results on fluorescence differences in Normal and HSIL groups' supernatant shows the potency of photodiagnosis application in cervical screening.

  19. Methodology for the use of proportional counters in pulsed fast neutron yield measurements

    OpenAIRE

    Tarifeño-Saldivia, Ariel; Mayer, Roberto E.; Pavez, Cristian; Soto, Leopoldo

    2011-01-01

    This paper introduces in full detail a methodology for the measurement of neutron yield and the necessary efficiency calibration, to be applied to the intensity measurement of neutron bursts where individual neutrons are not resolved in time, for any given moderated neutron proportional counter array. The method allows efficiency calibration employing the detection neutrons arising from an isotopic neutron source. Full statistical study of the procedure is descripted, taking into account cont...

  20. Measurement of diffusion of fluorescent compounds and autofluorescence in skin in vivo using a confocal instrument

    Science.gov (United States)

    Buttenschoen, K. K.; Sutton, E. E.; Daly, D.; Girkin, J. M.

    2016-02-01

    Using compact and affordable instrumentation based upon fluorescent confocal imaging we have tracked the movement of autofluorescent compounds through skin in near real time with high temporal and spatial resolution and sensitivity. The ability to measure the diffusion of compounds through skin with such resolution plays an important role for applications such as monitoring the penetration of pharmaceuticals applied to skin and assessing the integrity of the skin barrier. Several measurement methods exist, but they suffer from a number of problems such as being slow, expensive, non-portable and lacking sensitivity. To address these issues, we adapted a technique that we previously developed for tracking fluorescent compounds in the eye to measure the autofluorescence and the diffusion of externally applied fluorescent compounds in skin in vivo. Results are presented that show the change in autofluorescence of the volar forearm over the course of a week. We furthermore demonstrate the ability of the instrument to measure the diffusion speed and depth of externally applied fluorescent compounds both in healthy skin and after the skin barrier function has been perturbed. The instrument is currently being developed further for increased sensitivity and multi-wavelength excitation. We believe that the presented instrument is suitable for a large number of applications in fields such as assessment of damage to the skin barrier, development of topical and systemic medication and tracking the diffusion of fluorescent compounds through skin constructs as well as monitoring effects of skin products and general consumer products which may come into contact with the skin.

  1. Effect of Different Norms of Under-Mulch-Drip Irrigation on Diurnal Changes of Photosynthesis and Chlorophyll Fluorescence Parameter in High Yield Cotton of Xinjiang

    Institute of Scientific and Technical Information of China (English)

    ZHANG Wang-feng; REN Li-tong; WANG Zhen-lin; LI Shao-kun; GOU Ling; YU Songlie; CAO Lian-pu

    2003-01-01

    Under-mulch-drip irrigation is an advanced irrigation technique, which combines plastic-film-covered cultivation with drip irrigation. The influence of different norms of under-mulch-drip irrigation on di-urnal changes of photosynthetic rates and chlorophyll fluorescence parameters of cotton was studied, in orderto understand the physiological mechanisms of water-saving and high-yielding farming in Xinjiang. Results in-dicated that limited drip irrigation, which supplies 2/3 of 375 m3 ha-1 , the widely-used irrigation norm in cot-ton cultivation in Xinjiang, caused a water deficit in cotton field. Compared with the proper drip irrigation,the leaf photosynthetic rate under limited drip irrigation decreased during 9:00 to 11:00 a. m., and was sig-nificantly suppressed at midday, and then recovered afterwards. Using the chlorophyll fluorescence method,the absorption, transfer and transformation features of solar radiation by cotton leaf were investigated. Underlimited drip irrigation, the variable fluorescence (Fy) and primary light transfer efficiency of PSII (Fv/Fm)in cotton leaves were reduced because of the high light intensities and high temperatures at noon, and the de-crease in Xinluzao8 was greater than that in Xinluzao6. Therefore, it could be concluded that Xinluzao6 has ahigher drought-tolerance, and the Fv/Fm ratio could be used as a drought-resistance index for cotton.

  2. Surface studies and implanted helium measurements following NOVA high-yield DT experiments

    Energy Technology Data Exchange (ETDEWEB)

    Stoyer, M.A.; Hudson, G.B.

    1997-02-18

    This paper presents the results of three March 6, 1996 direct-drive high-yield DT NOVA experiments and provides `proof-of-principal` results for the quantitative measurement of energetic He ions. Semiconductor quality Si wafers and an amorphous carbon wafer were exposed to NOVA high-yield implosions. Surface damage was sub-micron in general, although the surface ablation was slightly greater for the carbon wafer than for the Si wafers. Melting of a thin ({approx} 0.1{mu}) layer of Si was evident from microscopic investigation. Electron microscopy indicated melted blobs of many different metals (e.g. Al, Au, Ta, Fe alloys, Cu and even Cd) on the surfaces. The yield measured by determining the numbers of atoms of implanted {sup 4}He and {sup 3}He indicate the number of DT fusions to be 9.1({plus_minus}2.3) X 10{sup 12} and DD fusions to be 4.8({plus_minus}1.0) x 10{sup 10}, respectively. The helium DT fusion yield is slightly lower than that of the Cu activation measurement, which was 1.3({plus_minus}0.l) x 10{sup 13} DT fusions.

  3. Photochemical properties in flag leaves of a super-high-yielding hybrid rice and a traditional hybrid rice (Oryza sativa L.) probed by chlorophyll a fluorescence transient.

    Science.gov (United States)

    Zhang, Meiping; Shan, YongJie; Kochian, Leon; Strasser, Reto J; Chen, GuoXiang

    2015-12-01

    Chlorophyll a fluorescence of flag leaves in a super-high-yielding hybrid rice (Oryza sativa L.) LYPJ, and a traditional hybrid rice SY63 cultivar with lower grain yield, which were grown in the field, were investigated from emergence through senescence of flag leaves. As the flag leaf matured, there was an increasing trend in photosynthetic parameters such as quantum efficiency of primary photochemistry ([Formula: see text] Po) and efficiency of electron transport from PS II to PS I (Ψ Eo). The overall photosynthetic performance index (PIABS) was significantly higher in the high-yielding LYPJ compared to SY63 during the entire reproductive stage of the plant, the same to MDA content. However, [Formula: see text] Po(=F V/F M), an indicator of the primary photochemistry of the flag leaf, did not display significant changes with leaf age and was not significantly different between the two cultivars, suggesting that PIABS is a more sensitive parameter than [Formula: see text] Po (=F V/F M) during leaf age for distinguishing between cultivars differing in yield.

  4. L subshell fluorescent $X$-ray measurements to study $CK$ transitions in the $66\\leqZ\\leq83$ region

    Indian Academy of Sciences (India)

    GURPREET KAUR; HIMANI BANSAL; M K TIWARI; RAJ MITTAL

    2016-08-01

    L subshell fluorescent X-rays in Dy, Ho, Er, Lu, Ta, W, Pt, Au, Hg, Pb and Bi have been measured using synchrotron with selective creation of electron vacancies in individual subshells. Coster--Kronig (CK) yields were derived from the measured intensities. Present measurements have been made at photon energies above the edges where differences between measured and theoretical attenuation coefficients are almost negligible. Parametric trends for the results with $Z$ were developed to cover all $Zs$ in the range of 66--83. The trends predict the switching-off of L1--L2, N1 transition at Z = 67. The extent of fall/rise of $f_Lij$ values corresponding to off/on of certain transitions is found inversely proportional to the difference in binding energies of two consecutive subshells involved in the transition. For $Zs$ above/below these rises/falls, $fL_13$ and $fL_12$ values are almost constants. $f_L23$ values involving no break at $Zs$ follow the general photoionization behaviour that ionization probability is highest at the edge energy and decreases with photon energy. Yield measurements with synchrotron radiation for Dy, Ho, Lu, Hg and Bi and experimental values for $f_L23$, $f_L12$ in Lu and for $f_L13$ in Ta are being quoted for the first time.

  5. Calibration methodology for proportional counters applied to yield measurements of a neutron burst

    Energy Technology Data Exchange (ETDEWEB)

    Tarifeño-Saldivia, Ariel, E-mail: atarifeno@cchen.cl, E-mail: atarisal@gmail.com; Pavez, Cristian; Soto, Leopoldo [Comisión Chilena de Energía Nuclear, Casilla 188-D, Santiago (Chile); Center for Research and Applications in Plasma Physics and Pulsed Power, P4, Santiago (Chile); Departamento de Ciencias Fisicas, Facultad de Ciencias Exactas, Universidad Andres Bello, Republica 220, Santiago (Chile); Mayer, Roberto E. [Instituto Balseiro and Centro Atómico Bariloche, Comisión Nacional de Energía Atómica and Universidad Nacional de Cuyo, San Carlos de Bariloche R8402AGP (Argentina)

    2014-01-15

    This paper introduces a methodology for the yield measurement of a neutron burst using neutron proportional counters. This methodology is to be applied when single neutron events cannot be resolved in time by nuclear standard electronics, or when a continuous current cannot be measured at the output of the counter. The methodology is based on the calibration of the counter in pulse mode, and the use of a statistical model to estimate the number of detected events from the accumulated charge resulting from the detection of the burst of neutrons. The model is developed and presented in full detail. For the measurement of fast neutron yields generated from plasma focus experiments using a moderated proportional counter, the implementation of the methodology is herein discussed. An experimental verification of the accuracy of the methodology is presented. An improvement of more than one order of magnitude in the accuracy of the detection system is obtained by using this methodology with respect to previous calibration methods.

  6. Calibration methodology for proportional counters applied to yield measurements of a neutron burst.

    Science.gov (United States)

    Tarifeño-Saldivia, Ariel; Mayer, Roberto E; Pavez, Cristian; Soto, Leopoldo

    2014-01-01

    This paper introduces a methodology for the yield measurement of a neutron burst using neutron proportional counters. This methodology is to be applied when single neutron events cannot be resolved in time by nuclear standard electronics, or when a continuous current cannot be measured at the output of the counter. The methodology is based on the calibration of the counter in pulse mode, and the use of a statistical model to estimate the number of detected events from the accumulated charge resulting from the detection of the burst of neutrons. The model is developed and presented in full detail. For the measurement of fast neutron yields generated from plasma focus experiments using a moderated proportional counter, the implementation of the methodology is herein discussed. An experimental verification of the accuracy of the methodology is presented. An improvement of more than one order of magnitude in the accuracy of the detection system is obtained by using this methodology with respect to previous calibration methods.

  7. Measurement of Flow Velocity and Inference of Liquid Viscosity in a Microfluidic Channel by Fluorescence Photobleaching

    DEFF Research Database (Denmark)

    Carroll, Nick J.; Jensen, Kaare Hartvig; Parsa, Shima

    2014-01-01

    We present a simple, noninvasive method for simultaneous measurement of flow velocity and inference of liquid viscosity in a microfluidic channel. We track the dynamics of a sharp front of photobleached fluorescent dye using a confocal microscope and measure the intensity at a single point...... downstream of the initial front position. We fit an exact solution of the advection diffusion equation to the fluorescence intensity recovery curve to determine the average flow velocity and the diffusion coefficient of the tracer dye. The dye diffusivity is correlated to solute concentration to infer...

  8. On the performance of bioanalytical fluorescence correlation spectroscopy measurements in a multiparameter photon-counting microscope

    Energy Technology Data Exchange (ETDEWEB)

    Mazouchi, Amir; Liu Baoxu; Bahram, Abdullah [Department of Physics, Institute for Optical Sciences, University of Toronto, Toronto (Canada); Department of Chemical and Physical Sciences, University of Toronto Mississauga, 3359 Mississauga Rd. N., Mississauga, ON, L5L 1C6 (Canada); Gradinaru, Claudiu C., E-mail: claudiu.gradinaru@utoronto.ca [Department of Physics, Institute for Optical Sciences, University of Toronto, Toronto (Canada); Department of Chemical and Physical Sciences, University of Toronto Mississauga, 3359 Mississauga Rd. N., Mississauga, ON, L5L 1C6 (Canada)

    2011-02-28

    Fluorescence correlation spectroscopy (FCS) data acquisition and analysis routines were developed and implemented in a home-built, multiparameter photon-counting microscope. Laser excitation conditions were investigated for two representative fluorescent probes, Rhodamine110 and enhanced green fluorescent protein (EGFP). Reliable local concentrations and diffusion constants were obtained by fitting measured FCS curves, provided that the excitation intensity did not exceed 20% of the saturation level for each fluorophore. Accurate results were obtained from FCS measurements for sample concentrations varying from pM to {mu}M range, as well as for conditions of high background signals. These experimental constraints were found to be determined by characteristics of the detection system and by the saturation behavior of the fluorescent probes. These factors actually limit the average number of photons that can be collected from a single fluorophore passing through the detection volume. The versatility of our setup and the data analysis capabilities were tested by measuring the mobility of EGFP in the nucleus of Drosophila cells under conditions of high concentration and molecular crowding. As a bioanalytical application, we studied by FCS the binding affinity of a novel peptide-based drug to the cancer-regulating STAT3 protein and corroborated the results with fluorescence polarization analysis derived from the same photon data.

  9. Noninvasive measurement of pharmacokinetics by near-infrared fluorescence imaging in the eye of mice

    Science.gov (United States)

    Dobosz, Michael; Strobel, Steffen; Stubenrauch, Kay-Gunnar; Osl, Franz; Scheuer, Werner

    2014-01-01

    Purpose: For generating preclinical pharmacokinetics (PKs) of compounds, blood is drawn at different time points and levels are quantified by different analytical methods. In order to receive statistically meaningful data, 3 to 5 animals are used for each time point to get serum peak-level and half-life of the compound. Both characteristics are determined by data interpolation, which may influence the accuracy of these values. We provide a method that allows continuous monitoring of blood levels noninvasively by measuring the fluorescence intensity of labeled compounds in the eye and other body regions of anesthetized mice. Procedures: The method evaluation was performed with four different fluorescent compounds: (i) indocyanine green, a nontargeting dye; (ii) OsteoSense750, a bone targeting agent; (iii) tumor targeting Trastuzumab-Alexa750; and (iv) its F(-alxea750 fragment. The latter was used for a direct comparison between fluorescence imaging and classical blood analysis using enzyme-linked immunosorbent assay (ELISA). Results: We found an excellent correlation between blood levels measured by noninvasive eye imaging with the results generated by classical methods. A strong correlation between eye imaging and ELISA was demonstrated for the F( fragment. Whole body imaging revealed a compound accumulation in the expected regions (e.g., liver, bone). Conclusions: The combination of eye and whole body fluorescence imaging enables the simultaneous measurement of blood PKs and biodistribution of fluorescent-labeled compounds.

  10. Measurements of periods, relative abundances and absolute yields of delayed neutrons from fast neutron induced fission of {sup 237}Np

    Energy Technology Data Exchange (ETDEWEB)

    Piksaikine, V. [Institute of Physics and Power Engineering, Obninsk (Russian Federation)

    1997-03-01

    The experimental method for measurements of the delayed neutron yields and period is presented. The preliminary results of the total yield, relative abundances and periods are shown comparing with the previously reported values. (J.P.N.)

  11. Measurements of periods, relative abundances and absolute yields of delayed neutrons from fast neutron induced fission of {sup 237}Np

    Energy Technology Data Exchange (ETDEWEB)

    Piksaikine, V. [Institute of Physics and Power Engineering, Obninsk (Russian Federation)

    1997-03-01

    The experimental method for measurements of the delayed neutron yields and period is presented. The preliminary results of the total yield, relative abundances and periods are shown comparing with the previously reported values. (J.P.N.)

  12. Laser scanning fluorescence microscopic measurement of the movement of cleaving egg surface of Rana Amurensis

    Institute of Scientific and Technical Information of China (English)

    GUGUOYAN; ChengtangXu; 等

    1995-01-01

    By laser scanning fluorescence microscopy for quantitative measurement of fluorescence intensity changes on egg surface stained with fluorescein isothiocyanate during cleavage furrow extending forward,it was found that in area of presumptive cleavage furrow the scanning curve became ∨ shape,indicating dark stripe appeared in that place.Then the fluorescence intensity increased at the place where the bottom of ∨ shape had located,and the scanning curve turned to ∧ shape,indicating single stripe was formed.While enhanced fluorescence appeared on the borders of ∧ shape,an M shape curve was found,showing double stripe occurred.During the distance between two borders of M shape incresing from 50μm to 100μm,a fluorescence peak came to sight in the middle of the M shape,which being the cleavge furrow bottom.The two lateral sides of furrow bottom with decreasing fluorescence were nascent membrane.At that time the curve became W shape.By the sides of cleavage furrow the the stress folds became conspicous after double stripe stage,showing the stretching of the egg surface being increased.With our[31,33]and others[32] reports that polylysine could induce the appearance of nascent membrane and phytohemagglutinins could decrease or prevent the appearance of nascent membrane,we believed the idea of Schroeder[25] that increasing mechanical stress could initiate nascent membrane formation and thought that the stresslay to the outsides of cleavage furrow.

  13. A new device designed for direct yield stress measurements of cement spacer

    Energy Technology Data Exchange (ETDEWEB)

    Gordon, C.L.; Tonmukayakul, P.; Morgan, R.L. [Halliburton Energy Services, Houston, TX (United States)

    2007-07-01

    The rheological properties of spacer fluids and cement slurries have a significant impact on the hydraulic shear stress of well casing walls. This paper described experimental studies and numerical models of a device designed to measure the yield stress and rheological properties of spacer and cement samples. The device was designed using the Couette principle for rheological measurements, and measured the yield stress of particle-laden samples between 4 and 150 degrees C. A sample contained in a gap between a stator and a blade located along the inside wall of a steel cup was analyzed using the device. A stator was attached to a torque device and remained static during the rheological measurement. Yield stress was measured by rotating the device at a low speed at 3 rpm and at steady state torque. Torque was recorded when the rotation stopped. Two aqueous mixtures of titanium oxide (TiO{sub 2}) particles were used for the experiment. A cement spacer comprised of a blend of barite, citric acid and water was also measured. A volume-averaged shear method was used to calculate shear rate and shear stress. Key dimensionless variables were the impeller Reynolds number; the Froude number; the Weber number; and the Weissenberg number. Accuracy was assessed by examining the data obtained with a model fluid where yield stress data was already determined. Results of the comparison showed that values obtained using the device were consistent and comparable with results obtained using other techniques. It was concluded that further research is needed to characterize the elastic fluids in the device. 13 refs., 2 tabs., 3 figs.

  14. Shipboard measurements of phytoplankton production and solar-stimulated fluorescence rates in the northwest Atlantic

    Science.gov (United States)

    Stegmann, P. M.; Lewis, M. R.

    1997-06-01

    We present results from a cruise to the Canadian sub-arctic and the Scotian Shelf designed to evaluate optical methods for bio-optical estimation of primary productivity. Vertical profiles of temperature and chlorophyll showed much variability from one station to the next, while primary production (normalized to biomass) ranged from 0.4 to 1 gC gChl -1 h -1 near the surface and decreased with depth. We used the linear model of Stegmann et al. (1992) (in Journal of Geophysical Research97, 627-638) to examine the relationship between solar-stimulated fluorescence and primary production and to determine the variability of the ratio of the quantum yield of photosynthesis, Φ c to the quantum yield of fluorescence, Φ f. We found that (1) there was a clear relation between production and fluorescence; (2) diurnal variations contributed to the variability in and (3) ranged from 0.32 to 0.42 molC Ein -1. The range of Φ found in this study is similar to the one from the equatorial Pacific (Stegmann et al., 1992, in Journal of Geophysical Research97, 627-638), despite the fact that the environmental conditions in the two regions were very different from each other. We did not find an increase in Φ c Φ as temperature increased.

  15. A novel fluorescent sensor for measurement of CFTR function by flow cytometry.

    Science.gov (United States)

    Vijftigschild, Lodewijk A W; van der Ent, Cornelis K; Beekman, Jeffrey M

    2013-06-01

    Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene cause cystic fibrosis. CFTR-dependent iodide transport measured by fluorescent quenching of ectopically expressed halide-sensitive yellow fluorescent protein (YFP) is widely being used to study CFTR function by microscopy or plate readers. Since YFP fluorescence in these systems is dependent on YFP expression levels and iodide concentration, differences in sensor expression level between experimental units are normalized at the start of each experiment. To allow accurate measurement of CFTR function by flow cytometry, we reasoned that co-expression of an iodide insensitive fluorescent protein would allow for normalization of sensor expression levels and more accurate quantification of CFTR function. Our data indicated that dsRed and mKate fluorescence are iodide insensitive, and we determined an optimal format for co-expression of these fluorescent proteins with halide-sensitive YFP. We showed using microscopy that ratiometric measurement (YFP/mKate) corrects for differences in sensor expression levels. Ratiometric measurements were essential to accurately measure CFTR function by flow cytometry that we here describe for the first time. Mixing of wild type or mutant CFTR expressing cells indicated that addition of approximately 10% of wild type CFTR expressing cells could be distinguished by ratiometric YFP quenching. Flow cytometric ratiometric YFP quenching also allowed us to study CFTR mutants associated with differential residual function upon ectopic expression. Compared with conventional plate-bound CFTR function assays, the flow cytometric approach described here can be used to study CFTR function in suspension cells. It may be further adapted to study CFTR function in heterologous cell populations using cell surface markers and selection of cells that display high CFTR function by cell sorting.

  16. Measurement of K{sup {+-}}{yields}{pi}{sup {+-}}{gamma}{gamma} decays

    Energy Technology Data Exchange (ETDEWEB)

    Morales Morales, Cristina

    2009-07-21

    The goal of this thesis was an experimental test of an effective theory of strong interactions at low energy, called Chiral Perturbation Theory (ChPT). Weak decays of kaon mesons provide such a test. In particular, K{sup {+-}} {yields} {pi}{sup {+-}}{gamma}{gamma} decays are interesting because there is no tree-level O(p{sup 2}) contribution in ChPT, and the leading contributions start at O(p{sup 4}). At this order, these decays include one undetermined coupling constant, c. Both the branching ratio and the spectrum shape of K{sup {+-}} {yields} {pi}{sup {+-}}{gamma}{gamma} decays are sensitive to this parameter. O(p{sup 6}) contributions to K{sup {+-}} {yields} {pi}{sup {+-}}{gamma}{gamma} ChPT predict a 30-40% increase in the branching ratio. From the measurement of the branching ratio and spectrum shape of K{sup {+-}} {yields} {pi}{sup {+-}}{gamma}{gamma} decays, it is possible to determine a model dependent value of c and also to examine whether the O(p{sup 6}) corrections are necessary and enough to explain the rate. About 40% of the data collected in the year 2003 by the NA48/2 experiment have been analyzed and 908 K{sup {+-}} {yields} {pi}{sup {+-}}{gamma}{gamma} candidates with about 8% background contamination have been selected in the region with z=m{sup 2}{sub {gamma}}{sub {gamma}}/m{sub K}{sup 2}{>=}0.2. Using 5,750,121 selected K{sup {+-}} {yields} {pi}{sup {+-}}{pi}{sup 0} decays as normalization channel, a model independent differential branching ratio of K{sup {+-}} {yields} {pi}{sup {+-}}{gamma}{gamma} has been measured to be: BR(K{sup {+-}} {yields} {pi}{sup {+-}}{gamma}{gamma}, z{>=}0.2)=(1.018{+-}0.038{sub stat}{+-}0.039{sub syst}{+-}0.004{sub ext}).10{sup -6}. From the fit to the O(p{sup 6}) ChPT prediction of the measured branching ratio and the shape of the z-spectrum, a value of c=1.54{+-}0.15{sub stat}{+-}0.18{sub syst} has been extracted. Using the measured c value and the O(p{sup 6}) ChPT prediction, the branching ratio for z=m{sup 2}{sub

  17. Predicting seed yield in perennial ryegrass using repeated canopy reflectance measurements and PLSR

    DEFF Research Database (Denmark)

    Gislum, René; Deleuran, Lise Christina; Boelt, Birte

    2009-01-01

    Repeated canopy reflectance measurements together with partial least-squares regression (PLSR) were used to predict seed yield in perennial ryegrass (Lolium perenne L.). The measurements were performed during the spring and summer growing seasons of 2001 to 2003 in three field experiments...... reflectance measurements was from approximately 600 cumulative growing degree-days (CGDD) to approximately 900 CGDD. This is the period just before and at heading of the seed crop. Furthermore, regression coefficients showed that information about N and water is important. The results support the development...

  18. Measurement of Scintillation and Ionization Yield and Scintillation Pulse Shape from Nuclear Recoils in Liquid Argon

    CERN Document Server

    Cao, H; Avetisyan, R; Back, H O; Cocco, A G; DeJongh, F; Fiorillo, G; Galbiati, C; Grandi, L; Guardincerri, Y; Kendziora, C; Lippincott, W H; Love, C; Lyons, S; Manenti, L; Martoff, C J; Meng, Y; Montanari, D; Mosteiro, P; Olvitt, D; Pordes, S; Qian, H; Rossi, B; Saldanha, R; Sangiorgio, S; Siegl, K; Strauss, S Y; Tan, W; Tatarowicz, J; Walker, S; Wang, H; Watson, A W; Westerdale, S; Yoo, J

    2014-01-01

    We have measured the scintillation and ionization yield of recoiling nuclei in liquid argon as a function of applied electric field by exposing a dual-phase Liquid Argon Time Projection Chamber (LAr-TPC) to a low energy pulsed narrowband neutron beam produced at the Notre Dame Institute for Structure and Nuclear Astrophysics. Liquid scintillation counters were arranged to detect and identify neutrons scattered in the TPC and to select the energy of the recoiling nuclei. We report measurements of the scintillation and ionization yields for nuclear recoils with energies from 10.3 to 57.2 keV and for applied electric fields from 0 to 1000 V/cm. We also report the observation of an anti-correlation between scintillation and ionization from nuclear recoils, which is similar to the anti-correlation between scintillation and ionization from electron recoils. A comparison of the light and charge yield of recoils parallel and perpendicular to the applied electric field yielded a first evidence of sensitivity to direct...

  19. Ruby fluorescence lifetime measurements for temperature determinations at high (p, T)

    Science.gov (United States)

    Bauer, Johannes D.; Bayarjargal, Lkhamsuren; Winkler, Björn

    2012-06-01

    The lifetime of the ruby R1 fluorescence line was measured as a function of pressure (up to about 20 GPa) and temperature (550 K) in an externally heated diamond anvil cell (DAC). At constant temperatures, the lifetime is increasing linearly with increasing pressure. The slope of the pressure dependence is constant up to a temperature of 450 K and it is decreasing at higher temperatures. At constant pressure, the lifetime is exponentially decreasing with increasing temperature. The (p, T)-dependence can be parametrized by the combination of a linear and an exponential function. This allows an accurate p, T-determination by the combination of fluorescence spectroscopy using Sm2+-doped strontium tetraborate and lifetime measurements of ruby, as the energy of the Sm2+ fluorescence is nearly temperature-independent.

  20. Composition measurement of bicomponent droplets using laser-induced fluorescence of acetone

    Science.gov (United States)

    Maqua, C.; Depredurand, V.; Castanet, G.; Wolff, M.; Lemoine, F.

    2007-12-01

    Commercial fuels are complex mixtures, the evaporation of which remains particularly difficult to model. Experimental characterization of the differential vaporization of the components is a problem that is seldom addressed. In this paper, the evaporation of binary droplets made of ethyl-alcohol and acetone is investigated using a technique of measurement of the droplet composition developed in purpose. This technique exploits the laser induced fluorescence of acetone which acts as a fluorescent tracer as well as the more volatile component of the fuel associated with an accurate measurement of the droplet diameter by forward scattering interferometry. A model of the fluorescence intensity of the binary mixture, taking into account the absorption of the acetone molecules, is proposed and validated. The sensitivity of the technique is discussed. Finally, the reliability of the technique is demonstrated on binary combusting droplets in linear stream.

  1. Direct spectrometry: a new alternative for measuring the fluorescence of composite resins and dental tissues.

    Science.gov (United States)

    da Silva, Tm; de Oliveira, Hpm; Severino, D; Balducci, I; Huhtala, Mfrl; Gonçalves, Sep

    2014-01-01

    The aim of this study was to evaluate the fluorescence intensity of different composite resins and compare those values with the fluorescence intensity of dental tissues. Different composite resins were used to make 10 discs (2 mm in depth and 4 mm in diameter) of each brand, divided into groups: 1) Z (Filtek Z350, 3M ESPE), 2) ES (Esthet-X, Dentsply), 3) A (Amelogen Plus, Ultradent), 4) DVS (Durafill-VS, Heraeus Kulzer) with 2 mm composite resin for enamel (A2), 5) OES ([Esthet-X] opaque-OA [1 mm] + enamel-A2 [1 mm]); 6) ODVSI ([Charisma-Opal/Durafill-VSI], opaque-OM (1 mm) + translucent [1mm]), and 7) DVSI ([Durafill- VSI] translucent [2 mm]). Dental tissue specimens were obtained from human anterior teeth cut in a mesiodistal direction to obtain enamel, dentin, and enamel/dentin samples (2 mm). The fluorescence intensity of specimens was directly measured using an optic fiber associated with a spectrometer (Ocean Optics USB 4000) and recorded in graphic form (Origin 8.0 program). Data were submitted to statistical analysis using Dunnet, Tukey, and Kruskall-Wallis tests. Light absorption of the composite resins was obtained in a spectral range from 250 to 450 nm, and that of dental tissues was between 250 and 300 nm. All composite resins were excited at 398 nm and exhibited maximum emissions of around 485 nm. Fluorescence intensity values for all of the resins showed statistically significant differences (measured in arbitrary units [AUs]), with the exception of groups Z and DVS. Group DVSI had the highest fluorescence intensity values (13539 AU), followed by ODVS (10440 AU), DVS (10146 AU), ES (3946 AU), OES (3841 AU), A (3540 AU), and Z (1146 AU). The fluorescence intensity values for the composite resins differed statistically from those of dental tissues (E=1380 AU; D=6262 AU; E/D=3251 AU). The opacity interfered with fluorescence intensity, and group Z demonstrated fluorescence intensity values closest to that of tooth enamel. It is concluded that the

  2. Measuring neutron yield and ρR anisotropies with activation foils at the National Ignition Facility

    Directory of Open Access Journals (Sweden)

    Bleuel D.L.

    2013-11-01

    Full Text Available Neutron yields at the National Ignition Facility (NIF are measured with a suite of diagnostics, including activation of ∼20–200 g samples of materials undergoing a variety of energy-dependent neutron reactions. Indium samples were mounted on the end of a Diagnostic Instrument Manipulator (DIM, 25–50 cm from the implosion, to measure 2.45 MeV D-D fusion neutron yield. The 336.2 keV gamma rays from the 4.5 hour isomer of 115mIn produced by (n,n′ reactions are counted in high-purity germanium detectors. For capsules producing D-T fusion reactions, zirconium and copper are activated via (n,2n reactions at various locations around the target chamber and bay, measuring the 14 MeV neutron yield to accuracies on order of 7%. By mounting zirconium samples on ports at nine locations around the NIF chamber, anisotropies in the primary neutron emission due to fuel areal density asymmetries can be measured to a relative precision of 3%.

  3. Time-domain measurement of fluorescence lifetime variation with pH

    Science.gov (United States)

    Ryder, Alan G.; Power, Sarah; Glynn, Thomas J.; Morrison, John J.

    2001-07-01

    Advances in the design and miniaturization of the lasers and electronics required for Time Correlated Single Photon Counting (TCSPC) measurement of fluorescence lifetime have simplified the use of the time domain method. We have assembled a compact portable system that is capable of measuring lifetimes down to approximately 200 ps (with deconvolution) and that can operate at a range of excitation and emission wavelengths. The excitation sources are pulsed LEDs and laser diodes with a maximum pulse rate of 40 MHz and are easily interchanged. Furthermore, the development of violet and blue GaN LEDs and laser diodes is expanding the range of fluorophores available for fluorescence lifetime measurement of ion concentrations. pH sensitive fluorophores have a wide range of biological and clinical applications. The use of fluorescence lifetime rather than intensity to measure pH has a number of advantages including the reduction of effects due to the photobleaching, scattering, and intensity variations in the excitation source. Using our compact TCSPC instrumentation we have measured the dependence of fluorescence lifetimes on pH for a range of dyes in phosphate buffer over the physiologically important range of 6.0 to 8.0. Most dyes exhibit only a small variation in lifetime (pH range; however, acridine exhibits a large variation in lifetime and hence shows promise as a pH indicator.

  4. A low cost fluorescence lifetime measurement system based on SPAD detectors and FPGA processing

    Science.gov (United States)

    Franch, N.; Alonso, O.; Canals, J.; Vilà, A.; Dieguez, A.

    2017-02-01

    This work presents a low cost fluorescence life time measurement system, aimed at carrying out fast diagnostic tests through label detection in a portable system so it can be used in a medical consultation, within a short time span. The system uses Time Correlated Single Photon Counting (TCSPC), measuring the arrival time of individual photons and building a histogram of those times, showing the fluorescence decay of the label which is characteristic of each fluorescent substance. The system is implemented using a Xilinx FPGA which controls the experiment and includes a Time to Digital Converter (TDC) to perform measurements with a resolution in the order of tenths of picoseconds. Also included are a laser diode and the driving electronics to generate short pulses as well as a HV-CMOS implemented Single Photon Avalanche Diode (SPAD) as a high gain sensor. The system is entirely configurable so it can easily be adapted to the target label molecule and measurement needs. The histogram is constructed within the FPGA and can then be read as convenient. Various performance parameters are also shown, as well as experimental measurements of a quantum dot fluorescence decay as a proof of concept.

  5. Quantum Yield Determination Based on Photon Number Measurement, Protocols for Firefly Bioluminescence Reactions.

    Science.gov (United States)

    Niwa, Kazuki

    2016-01-01

    Quantum yield (QY), which is defined as the probability of photon production by a single bio/chemiluminescence reaction, is an important factor to characterize luminescence light intensity emitted diffusively from the reaction solution mixture. Here, methods to measure number of photons to determine QY according to the techniques of national radiometry standards are described. As an example, experiments using firefly bioluminescence reactions are introduced.

  6. Measurement of Direct Photon Emission in K{sup +}{yields}{pi}{sup +}{pi}

    Energy Technology Data Exchange (ETDEWEB)

    Adler, S.; Aoki, M.; Ardebili, M.; Atiya, M. S.; Bergbusch, P. C.; Blackmore, E. W.; Bryman, D. A.; Chiang, I.-H.; Convery, M. R.; Diwan, M. V. (and others)

    2000-12-04

    We have performed a measurement of the K{sup +}{yields}{pi}{sup +}{pi}{sup 0}{gamma} decay and have observed 2x10{sup 4} events. The best fit to the decay spectrum gives a branching ratio for direct photon emission of (4.7{+-}0.8{+-}0.3)x10{sup -6} in the {pi}{sup +} kinetic energy region of 55 to 90MeV and requires no component due to interference with inner bremsstrahlung.

  7. SOFIA: An innovative setup to measure complete isotopic yield of fission fragments

    Directory of Open Access Journals (Sweden)

    Pellereau E.

    2013-12-01

    Full Text Available We performed an experiment dedicated to the accurate isotopic yield measurement of fission fragments over the whole range. SOFIA exploits the inverse kinematics technique: using heavy ion beams at relativistic energies, fission is induced by Coulomb excitation in a high-Z target. The fragments are emitted forward and both of them are identified in charge and mass. The setup will be presented, as well as preliminary spectra.

  8. Setup for measurements of partial ion yields at the Synchrotron Radiation Center

    Science.gov (United States)

    Wehlitz, R.; Lukić, D.; Koncz, C.; Sellin, I. A.

    2002-03-01

    A new setup for measuring partial photoion yields was developed and built at the Synchrotron Radiation Center. The vacuum chamber, which accommodates an ion time-of-flight spectrometer, a metal vapor oven, and a liquid nitrogen cooled trap, consists mainly of a standard conflat 6 in. six-way cross and a 6 in. tee. A differential pumping stage separates the vacuum chamber from the beam line. First experiments with this apparatus were performed using neon, lithium, and beryllium.

  9. Measurement of light and charge yield of low-energy electronic recoils in liquid xenon

    CERN Document Server

    Goetzke, L W; Anthony, M; Plante, G; Weber, M

    2016-01-01

    The dependence of the light and charge yield of liquid xenon on the applied electric field and recoil energy is important for dark matter detectors using liquid xenon time projections chambers. Few measurements have been made of this field dependence at recoil energies less than 10 keV. In this paper we present results of such measurements using a specialized detector. Recoil energies are determined via the Compton coincidence technique at four drift fields relevant for liquid xenon dark matter detectors: 0.19, 0.48, 1.02, and 2.32 kV/cm. Mean recoil energies down to 1 keV were measured with unprecedented precision. We find that the charge and light yield are anti-correlated above 3 keV, and that the field dependence becomes negligible below 6 keV. However, below 3 keV we find a charge yield significantly higher than expectation and a reconstructed energy deviating from linearity.

  10. 10 CFR Appendix Q to Subpart B of... - Uniform Test Method for Measuring the Energy Consumption of Fluorescent Lamp Ballasts

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 3 2010-01-01 2010-01-01 false Uniform Test Method for Measuring the Energy Consumption... Appendix Q to Subpart B of Part 430—Uniform Test Method for Measuring the Energy Consumption of Fluorescent... reference; see § 430.3). The test for measuring standby mode energy consumption of fluorescent lamp ballasts...

  11. Shading correction and calibration in bacterial fluorescence measurement by image processing system

    NARCIS (Netherlands)

    Wilkinson, M.H.F.

    1994-01-01

    An image processing system with applications in bacterial (immuno-)fluorescence measurement has been developed. To reach quantitative results, correction for non-uniformities in system sensitivity, both as a function of time (calibration for drifts) and as a function of image coordinates (shading co

  12. Shading correction and calibration in bacterial fluorescence measurement by image processing system

    NARCIS (Netherlands)

    Wilkinson, M.H.F.

    1994-01-01

    An image processing system with applications in bacterial (immuno-)fluorescence measurement has been developed. To reach quantitative results, correction for non-uniformities in system sensitivity, both as a function of time (calibration for drifts) and as a function of image coordinates (shading co

  13. Formation of nitric oxide in an industrial burner measured by 2-D laser induced fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Arnold, A.; Bombach, R.; Kaeppeli, B. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-06-01

    We have performed two-dimensional Laser Induced Fluorescence (2-D LIF) measurements of nitric oxide and hydroxyl radical distributions in an industrial burner at atmospheric pressure. The relative 2-D LIF data of NO were set to an absolute scale by calibration with probe sampling combined with gas analysis. (author) 3 figs., 7 refs.

  14. Simultaneous measurement of position and color of single fluorescent emitters using diffractive optics

    NARCIS (Netherlands)

    Broeken, J.; Rieger, B.; Stallinga, S.

    2014-01-01

    We propose a method for simultaneously measuring the position and emission color of single fluorescent emitters based on the use of a large pitch diffraction grating in the emission light path. The grating produces satellite spots adjacent to the main spot; the relative distance between the spots is

  15. Reliable measurement of E. coli single cell fluorescence distribution using a standard microscope set-up.

    Science.gov (United States)

    Cortesi, Marilisa; Bandiera, Lucia; Pasini, Alice; Bevilacqua, Alessandro; Gherardi, Alessandro; Furini, Simone; Giordano, Emanuele

    2017-01-01

    Quantifying gene expression at single cell level is fundamental for the complete characterization of synthetic gene circuits, due to the significant impact of noise and inter-cellular variability on the system's functionality. Commercial set-ups that allow the acquisition of fluorescent signal at single cell level (flow cytometers or quantitative microscopes) are expensive apparatuses that are hardly affordable by small laboratories. A protocol that makes a standard optical microscope able to acquire quantitative, single cell, fluorescent data from a bacterial population transformed with synthetic gene circuitry is presented. Single cell fluorescence values, acquired with a microscope set-up and processed with custom-made software, are compared with results that were obtained with a flow cytometer in a bacterial population transformed with the same gene circuitry. The high correlation between data from the two experimental set-ups, with a correlation coefficient computed over the tested dynamic range > 0.99, proves that a standard optical microscope- when coupled with appropriate software for image processing- might be used for quantitative single-cell fluorescence measurements. The calibration of the set-up, together with its validation, is described. The experimental protocol described in this paper makes quantitative measurement of single cell fluorescence accessible to laboratories equipped with standard optical microscope set-ups. Our method allows for an affordable measurement/quantification of intercellular variability, whose better understanding of this phenomenon will improve our comprehension of cellular behaviors and the design of synthetic gene circuits. All the required software is freely available to the synthetic biology community (MUSIQ Microscope flUorescence SIngle cell Quantification).

  16. YieldStar based reticle 3D measurements and its application

    Science.gov (United States)

    Vaenkatesan, Vidya; Finders, Jo; ten Berge, Peter; Plug, Reinder; Sijben, Anko; Schellekens, Twan; Dillen, Harm; Pocobiej, Wojciech; Jorge, Vasco G.; van Dijck, Jurgen

    2016-09-01

    YieldStar (YS) is an established ASML-built scatterometer that is capable of measuring wafer Critical Dimension (CD), Overlay and Focus. In a recent work, the application range of YS was extended to measure 3D CD patterns on a reticle (pattern CD, height, Side Wall Angle-SWA). The primary motivation for this study came from imaging studies that indicated a need for measuring and controlling reticle 3D topography. CD scanning electron microscope (CD-SEM), Atomic force microscope (AFM), 3D multiple detector SEM (3D-SEM) are the preferred tools for reticle metrology. While these tools serve the industry well, the current research to the impact of reticle 3D involves extensive costs, logistic challenges and increased reticle lead time. YS provides an attractive alternative as it can measure pattern CD, SWA and height in a single measurement and at high throughput. This work demonstrates the capability of YS as a reticle metrology tool.

  17. N-acetylcysteine increased rice yield

    OpenAIRE

    NOZULAIDI, MOHD; JAHAN, MD SARWAR; KHAIRI, MOHD; Khandaker, Mohammad Moneruzzaman; Mat NASHRIYAH; KHANIF, YUSOP MOHD

    2015-01-01

    N-acetylcysteine (NAC) biosynthesized reduced glutathione (GSH), which maintains redox homeostasis in plants under normal and stressful conditions. To justify the effects of NAC on rice production, we measured yield parameters, chlorophyll (Chl) content, minimum Chl fluorescence (Fo), maximum Chl fluorescence (Fm), quantum yield (Fv/Fm), net photosynthesis rate (Pn), photosynthetically active radiation (PAR), and relative water content (RWC). Four treatments, N1G0 (nitrogen (N) with no NAC), ...

  18. A new method for measuring concentration of a fluorescent tracer in bubbly gas-liquid flows

    Science.gov (United States)

    Moghaddas, J. S.; Trägårdh, C.; Kovacs, T.; Östergren, K.

    2002-06-01

    A new experimental model, the two-tracer method (TTM), based on the planar laser-induced fluorescence technique (PLIF), is presented for the measurement of the local concentration of a fluorescent tracer in the liquid phase of a bubbly two-phase system. Light scattering and shading effects due to the bubbles were compensated for using the new model. The TTM results were found to give more accurate predictions of the local concentration than the normal PLIF method in a bubbly two-phase system.

  19. Ultrafast Energy Transfer in Artificial Antenna Molecule Measured by Transient Fluorescence Spectroscopy

    Institute of Scientific and Technical Information of China (English)

    Hai-long Chen; Yu-xiang Weng; Xi-you Li

    2011-01-01

    We have reported previously the ultrafast energy transfer process with a time constant of 0.8 ps from a monomeric to a dimeric subunit within a perylenetetracarboxylic diimide trimer, which was derived indirectly from a model fitting into the transient absorption ex perimental data. Here we present a direct ultrafast fluorescence quenching measurement by employing fs time-resolved transient fluorescence spectroscopy based on noncollinear optical parametric amplification technique. The rapid decay of the monomer's emission due to energy transfer was observed directly with a time constant of about 0.82 ps, in good agreement with the previous result.

  20. Measurement of Breaking Force of Fluorescence Labelled Microtubules with Optical Tweezers

    Institute of Scientific and Technical Information of China (English)

    LIU Chun-Xiang; GUO Hong-Lian; XU Chun-Hua; YUAN Ming; LI Znao-Lin; CHENG Bing-Ying; ZHANG Dao-Zhong

    2005-01-01

    @@ Under illumination of excitation light, the force that can make fluorescent dye-labelled microtubules break up is measured by using dual-beam optical tweezers. It is found that this force is about several piconewtons, which is two orders of magnitude smaller than that without fluorescence label. Microtubules can be elongated about 20% and the increase of the tensile force is nonlinear with the microtubule elongation. Some qualitative explanations are given for the mechanisms about the breakup and elongation of microtubules exposed to excitation light.

  1. Measurement of scintillation and ionization yield and scintillation pulse shape from nuclear recoils in liquid argon

    Energy Technology Data Exchange (ETDEWEB)

    Cao, H.; Alexander, T.; Aprahamian, A.; Avetisyan, R.; Back, H. O.; Cocco, A. G.; DeJongh, F.; Fiorillo, G.; Galbiati, C.; Grandi, L.; Guardincerri, Y.; Kendziora, C.; Lippincott, W. H.; Love, C.; Lyons, S.; Manenti, L.; Martoff, C. J.; Meng, Y.; Montanari, D.; Mosteiro, P.; Olvitt, D.; Pordes, S.; Qian, H.; Rossi, B.; Saldanha, R.; Sangiorgio, S.; Siegl, K.; Strauss, S. Y.; Tan, W.; Tatarowicz, J.; Walker, S.; Wang, H.; Watson, A. W.; Westerdale, S.; Yoo, J.

    2015-05-01

    We have measured the scintillation and ionization yield of recoiling nuclei in liquid argon as a function of applied electric field by exposing a dual-phase liquid argon time projection chamber (LAr-TPC) to a low energy pulsed narrow band neutron beam produced at the Notre Dame Institute for Structure and Nuclear Astrophysics. Liquid scintillation counters were arranged to detect and identify neutrons scattered in the TPC and to select the energy of the recoiling nuclei. We report measurements of the scintillation yields for nuclear recoils with energies from 10.3 to 57.3 keV and for median applied electric fields from 0 to 970 V / cm . For the ionization yields, we report measurements from 16.9 to 57.3 keV and for electric fields from 96.4 to 486 V / cm . We also report the observation of an anticorrelation between scintillation and ionization from nuclear recoils, which is similar to the anticorrelation between scintillation and ionization from electron recoils. Assuming that the energy loss partitions into excitons and ion pairs from 83 m Kr internal conversion electrons is comparable to that from 207 Bi conversion electrons, we obtained the numbers of excitons ( N ex ) and ion pairs ( N i ) and their ratio ( N ex / N i ) produced by nuclear recoils from 16.9 to 57.3 keV. Motivated by arguments suggesting direction sensitivity in LAr-TPC signals due to columnar recombination, a comparison of the light and charge yield of recoils parallel and perpendicular to the applied electric field is presented for the first time.

  2. Patterning pallet arrays for cell selection based on high-resolution measurements of fluorescent biosensors.

    Science.gov (United States)

    Shadpour, Hamed; Zawistowski, Jon S; Herman, Annadele; Hahn, Klaus; Allbritton, Nancy L

    2011-06-24

    Pallet arrays enable cells to be separated while they remain adherent to a surface and provide a much greater range of cell selection criteria relative to that of current technologies. However there remains a need to further broaden cell selection criteria to include dynamic intracellular signaling events. To demonstrate the feasibility of measuring cellular protein behavior on the arrays using high resolution microscopy, the surfaces of individual pallets were modified to minimize the impact of scattered light at the pallet edges. The surfaces of the three-dimensional pallets on an array were patterned with a coating such as fibronectin using a customized stamping tool. Micropatterns of varying shape and size were printed in designated regions on the pallets in single or multiple steps to demonstrate the reliability and precision of patterning molecules on the pallet surface. Use of a fibronectin matrix stamped at the center of each pallet permitted the localization of H1299 and mouse embryonic fibroblast (MEF) cells to the pallet centers and away from the edges. Compared to pallet arrays with fibronectin coating the entire top surface, arrays with a central fibronectin pattern increased the percentage of cells localized to the pallet center by 3-4-fold. Localization of cells to the pallet center also enabled the physical separation of cells from optical artifacts created by the rough pallet side walls. To demonstrate the measurement of dynamic intracellular signaling on the arrays, fluorescence measurements of high spatial resolution were performed using a RhoA GTPase biosensor. This biosensor utilized fluorescence resonance energy transfer (FRET) between cyan fluorescent protein (CFP) and yellow fluorescent protein (YFP) to measure localized RhoA activity in cellular ruffles at the cell periphery. These results demonstrated the ability to perform spatially resolved measurements of fluorescence-based sensors on the pallet arrays. Thus, the patterned pallet arrays

  3. Spectroscopic fluorescence measurements of lamb and human heart tissue in vitro

    Science.gov (United States)

    Filippidis, George; Zacharakis, Giannis; Kochiadakis, G. E.; Chrysostomakis, S. I.; Vardas, P. E.; Fotakis, Costas; Papazoglou, Theodore G.

    2003-10-01

    Laser-induced fluorescence spectra were obtained during the exposure of lamb heart (n=20) tissue to Argon-ion radiation (457.9nm). Fluorescence spectra from different heart compartments (the left and right atria and ventricles, the myocardium, the epicardium, and the aorta) were recorded. Simple algebraic algorithms based on the spectral intensity variation were constructed in order to detect spectral features and characterize the different cardiac compartments. Additionally, it was investigated whether each chamber exhibited constant spectral response. After the end of each experiment the lamb hearts were stored in formalin (10%). The samples were irradiated again after forty eight (48) hours in order to investigate the spectral differences that appear due to formalin conservation. Similar fluorescence measurements were taken from a limited number of human heart tissues (n=2) ex vivo.

  4. Fluorescence measurements for evaluating the application of multivariate analysis techniques to optically thick environments.

    Energy Technology Data Exchange (ETDEWEB)

    Reichardt, Thomas A.; Timlin, Jerilyn Ann; Jones, Howland D. T.; Sickafoose, Shane M.; Schmitt, Randal L.

    2010-09-01

    Laser-induced fluorescence measurements of cuvette-contained laser dye mixtures are made for evaluation of multivariate analysis techniques to optically thick environments. Nine mixtures of Coumarin 500 and Rhodamine 610 are analyzed, as well as the pure dyes. For each sample, the cuvette is positioned on a two-axis translation stage to allow the interrogation at different spatial locations, allowing the examination of both primary (absorption of the laser light) and secondary (absorption of the fluorescence) inner filter effects. In addition to these expected inner filter effects, we find evidence that a portion of the absorbed fluorescence is re-emitted. A total of 688 spectra are acquired for the evaluation of multivariate analysis approaches to account for nonlinear effects.

  5. Measurement of fluorescent probes concentration ratio in the cerebrospinal fluid for early detection of Alzheimer's disease

    Science.gov (United States)

    Harbater, Osnat; Gannot, Israel

    2014-03-01

    The pathogenic process of Alzheimer's Disease (AD), characterized by amyloid plaques and neurofibrillary tangles in the brain, begins years before the clinical diagnosis. Here, we suggest a novel method which may detect AD up to nine years earlier than current exams, minimally invasive, with minimal risk, pain and side effects. The method is based on previous reports which relate the concentrations of biomarkers in the Cerebrospinal Fluid (CSF) (Aβ and Tau proteins) to the future development of AD in mild cognitive impairment patients. Our method, which uses fluorescence measurements of the relative concentrations of the CSF biomarkers, replaces the lumbar puncture process required for CSF drawing. The process uses a miniature needle coupled trough an optical fiber to a laser source and a detector. The laser radiation excites fluorescent probes which were prior injected and bond to the CSF biomarkers. Using the ratio between the fluorescence intensities emitted from the two biomarkers, which is correlated to their concentration ratio, the patient's risk of developing AD is estimated. A theoretical model was developed and validated using Monte Carlo simulations, demonstrating the relation between fluorescence emission and biomarker concentration. The method was tested using multi-layered tissue phantoms simulating the epidural fat, the CSF in the sub-arachnoid space and the bone. These phantoms were prepared with different scattering and absorption coefficients, thicknesses and fluorescence concentrations in order to simulate variations in human anatomy and in the needle location. The theoretical and in-vitro results are compared and the method's accuracy is discussed.

  6. Reflectance and fluorescence characterization of maize species using field laboratory measurements and lidar remote sensing.

    Science.gov (United States)

    Zhao, Guangyu; Duan, Zheng; Ming, Lian; Li, Yiyun; Chen, Ruipeng; Hu, Jiandong; Svanberg, Sune; Han, Yanlai

    2016-07-01

    Laser-induced fluorescence is an important technique to study photosynthesis and plants. Information on chlorophyll and other pigments can be obtained. We have been using a mobile laboratory in a Chinese experimental farm setting to study maize (Zea mays L.) leaves by reflectance and fluorescence measurements and correlated the spectroscopic signals to the amount of fertilizer supplied. Further, we studied five different species of maize using the remote monitoring of the fluorescence signatures obtained with the same mobile laboratory, but now in a laser radar remote-sensing configuration. The system separation from the target area was 50 m, and 355 nm pulsed excitation using the frequency-tripled output from an Nd:YAG laser was employed. Principal component analysis and linear discriminant analysis were combined to identify the different maize species using their fluorescence spectra. Likewise, the spectral signatures in reflectance and fluorescence frequently allowed us to separate different fertilizer levels applied to plants of the same species.

  7. New measurement on photon yields from air and the application to the energy estimation of primary cosmic rays

    CERN Document Server

    Nagano, M; Sakaki, N; Ando, K

    2004-01-01

    The air fluorescence technique is used to detect ultra-high energy cosmic rays (UHECR), and to estimate their energy. Of fundamental importance is the photon yield due to excitation by electrons, in air of various densities and temperatures. After our previous report, the experiment has been continued using a Sr90 $\\beta$ source to study the pressure dependence of photon yields for radiation in nitrogen and dry air. The photon yields in 15 wave bands between 300 nm and 430 nm have been determined. The total photon yield between 300 nm and 406 nm (used in most experiments) in air excited by a 0.85 MeV electron is 3.81+-0.13 (+-13 % systematics) photons per meter at 1013 hPa and 20 $^{\\circ}$C. The air density and temperature dependencies of 15 wave bands are given for application to UHECR observations.

  8. Taming fluorescence yield of dye insensitive to temperature by non-covalent complex with the host CB[7] for aqueous dye lasers

    Indian Academy of Sciences (India)

    Monika Gupta; Krishna K Jagtap; V Sudarsan; Alok K Ray

    2014-02-01

    Quantum yield of fluorescence (QYF) of widely used Rhodamine (RhB) dye in ethanol and water was observed to decrease rapidly with increase in temperature of the dye solutions, which was correlated to enhanced torsional motion of its flexible diethylamino groups. This is harmful for its use in high-average power dye lasers, pumped by copper vapour laser (CVL) or diodepumped solid-state green laser (DPSSGL), in which bulk temperature of the dye solution was found to increase due to the heat generated by circulation pumps and non-radiative decay processes of excited dye molecules. The QYF of RhB dye in water was found to be not sensitive to temperature in the practical operating region 16–25°C of dye laser by adopting supramolecular route to form an inclusion complex of RhB with the container molecule cucurbit[7]uril (CB[7]).

  9. Dirac-Fock calculations of K -, L -, and M -shell fluorescence and Coster-Kronig yields for Ne, Ar, Kr, Xe, Rn, and Uuo

    Science.gov (United States)

    Sampaio, J. M.; Madeira, T. I.; Guerra, M.; Parente, F.; Santos, J. P.; Indelicato, P.; Marques, J. P.

    2015-05-01

    In this work, we calculated the fluorescence and Coster-Kronig yields for the K shell and the L and M subshells of Ne, Ar, Kr, Xe, Rn, and Uuo (Z =118 ), using a Dirac-Fock model which provides a better description of the electron-electron interaction than previous approaches, and is suitable to handle superheavy elements. The results are compared with available data from other authors. In what concerns Ne, Ar, Kr, Xe, and Rn K shells, the obtained results are in very good agreement with the adopted values of Krause [25] and with experiment when available. For the L subshells, our results are in line with existing ones. For the M subshells and for all shells of Uuo there are no previous experimental and theoretical results to compare to our calculations.

  10. Slow-Injection Growth of Seeded CdSe/CdS Nanorods with Unity Fluorescence Quantum Yield and Complete Shell to Core Energy Transfer.

    Science.gov (United States)

    Coropceanu, Igor; Rossinelli, Aurelio; Caram, Justin R; Freyria, Francesca S; Bawendi, Moungi G

    2016-03-22

    A two-step process has been developed for growing the shell of CdSe/CdS core/shell nanorods. The method combines an established fast-injection-based step to create the initial elongated shell with a second slow-injection growth that allows for a systematic variation of the shell thickness while maintaining a high degree of monodispersity at the batch level and enhancing the uniformity at the single-nanorod level. The second growth step resulted in nanorods exhibiting a fluorescence quantum yield up to 100% as well as effectively complete energy transfer from the shell to the core. This improvement suggests that the second step is associated with a strong suppression of the nonradiative channels operating both before and after the thermalization of the exciton. This hypothesis is supported by the suppression of a defect band, ubiquitous to CdSe-based nanocrystals after the second growth.

  11. Material/element-dependent fluorescence-yield modes on soft X-ray absorption spectroscopy of cathode materials for Li-ion batteries

    Directory of Open Access Journals (Sweden)

    Daisuke Asakura

    2016-03-01

    Full Text Available We evaluate the utilities of fluorescence-yield (FY modes in soft X-ray absorption spectroscopy (XAS of several cathode materials for Li-ion batteries. In the case of total-FY (TFY XAS for LiNi0.5Mn1.5O4, the line shape of the Mn L3-edge XAS was largely distorted by the self-absorption and saturation effects, while the distortions were less pronounced at the Ni L3 edge. The distortions were suppressed for the inverse-partial-FY (IPFY spectra. We found that, in the cathode materials, the IPFY XAS is highly effective for the Cr, Mn, and Fe L edges and the TFY and PFY modes are useful enough for the Ni L edge which is far from the O K edge.

  12. Measuring Fluorescent Dye in the Bubbly and Sediment-Laden Surfzone

    OpenAIRE

    Clark, David B.; Feddersen, Falk; Omand, Melissa M.; Guza, R.T.

    2009-01-01

    Decisions about recreational beach closures would be enhanced if better estimates of surfzone contaminant transport and dilution were available. In situ methods for measuring fluorescent Rhodamine WT dye tracer in the surfzone are presented, increasing the temporal and spatial resolution over previous surfzone techniques. Bubbles and sand suspended by breaking waves in the surfzone interfere with in situ optical fluorometer dye measurements, increasing the lower bound for dye detection (≈ 1 p...

  13. Polarized fluorescence measurements of orientational order in a uniaxial liquid crystal

    DEFF Research Database (Denmark)

    Chapoy, L. Lawrence; DuPré, Donald B.

    1979-01-01

    The second and fourth orientational order parameters and , have been measured throughout the liquid crystalline phase of p-methoxybenzylidene-p[prime]-n-butylaniline (MBBA) using small quantities of a fluorescent probe. Complications of rotational Brownian motion and the intramolecular transfer...... of excitation energy were considered in the analysis. The results are in agreement with previous Raman measurements on the doped liquid crystal. The Journal of Chemical Physics is copyrighted by The American Institute of Physics....

  14. Measurement and simulation of the muon-induced neutron yield in lead

    CERN Document Server

    Reichhart, L; Akimov, D Yu; Araujo, H M; Barnes, E J; Belov, V A; Bewick, A; Burenkov, A A; Chepel, V; Currie, A; DeViveiros, L; Edwards, B; Francis, V; Ghag, C; Hollingsworth, A; Horn, M; Kalmus, G E; Kobyakin, A S; Kovalenko, A G; Kudryavtsev, V A; Lebedenko, V N; Lopes, M I; Luscher, R; Majewski, P; Murphy, A St J; Neves, F; Paling, S M; da Cunha, J Pinto; Preece, R; Quenby, J J; Scovell, P R; Silva, C; Solovov, V N; Smith, N J T; Smith, P F; Stekhanov, V N; Sumner, T J; Thorne, C; Walker, R J

    2013-01-01

    A measurement is presented of the neutron production rate in lead by high energy cosmic-ray muons at a depth of 2850 m water equivalent (w.e.) and a mean muon energy of 260 GeV. The measurement exploits the delayed coincidences between muons and the radiative capture of induced neutrons in a highly segmented tonne scale plastic scintillator detector. Detailed Monte Carlo simulations reproduce well the measured capture times and multiplicities and, within the dynamic range of the instrumentation, the spectrum of energy deposits. By comparing measurements with simulations of neutron capture rates a neutron yield in lead of (5.8 +/- 0.2) x 10^-3 neutrons/muon/(g/cm^2) has been obtained. Absolute agreement between simulation and data is of order 25%. Consequences for deep underground rare event searches are discussed.

  15. $K$-series X-rays yield measurement of kaonic hydrogen atoms in gaseous target

    CERN Document Server

    Bazzi, M; Bellotti, G; Berucci, C; Bragadireanu, A M; Bosnar, D; Cargnelli, M; Curceanu, C; Butt, A D; d'Uffizi, A; Fiorini, C; Ghio, F; Guaraldo, C; Hayanao, R S; Iliescu, M; Ishiwatari, T; Iwasaki, M; Sandri, P Levi; Marton, J; Okada, S; Pietreanu, D; Piscicchia, K; Vidal, A Romero; Sbardella, E; Scordo, A; Shi, H; Sirghi, D L; Sirghi, F; Tatsuno, H; Doce, O Vazquez; Widmann, E; Zmeskal, J

    2016-01-01

    We measured the $K$-series X-rays of the $K^{-}p$ exotic atom in the SIDDHARTA experiment with a gaseous hydrogen target of 1.3 g/l, which is about 15 times the $\\rho_{\\rm STP}$ of hydrogen gas. At this density, the absolute yields of kaonic X-rays, when a negatively charged kaon stopped inside the target, were determined to be 0.012$^{+0.004}_{-0.003}$ for $K_{\\alpha}$ and 0.043$^{+0.012}_{-0.011}$ for all the $K$-series transitions $K_{tot}$. These results, together with the KEK E228 experiment results, confirm for the first time a target density dependence of the yield predicted by the cascade models, and provide valuable information to refine the parameters used in the cascade models for the kaonic atoms.

  16. Comprehensive Measurement of Neutron Yield Produced by 62 MeV Protons on Beryllium Target

    CERN Document Server

    Osipenko, M; Alba, R; Ricco, G; Schillaci, M; Barbagallo, M; Boccaccio, P; Celentano, A; Colonna, N; Cosentino, L; Del Zoppo, A; Di Pietro, A; Esposito, J; Figuera, P; Finocchiaro, P; Kostyukov, A; Maiolino, C; Santonocito, D; Scuderi, V; Viberti, C M

    2013-01-01

    A low-power prototype of neutron amplifier, based on a 70 MeV, high current proton cyclotron being installed at LNL for the SPES RIB facility, was recently proposed within INFN-E project. This prototype uses a thick Beryllium converter to produce a fast neutron spectrum feeding a sub-critical reactor core. To complete the design of such facility the new measurement of neutron yield from a thick Beryllium target was performed at LNS. This measurement used liquid scintillator detectors to identify produced neutrons by Pulse Shape Discrimination and Time of Flight technique to measure neutron energy in the range 0.5-62 MeV. To extend the covered neutron energy range He3 detector was used to measure neutrons below 0.5 MeV. The obtained yields were normalized to the charge deposited by the proton beam on the metallic Beryllium target. These techniques allowed to achieve a wide angular coverage from 0 to 150 degrees and to explore almost complete neutron energy interval.

  17. Neutron spectroscopy by thermalization light yield measurement in a composite heterogeneous scintillator

    Energy Technology Data Exchange (ETDEWEB)

    Shi, T.; Nattress, J.; Mayer, Michael F.; Lin, M-W; Jovanovic, Igor

    2016-12-11

    An exothermic neutron capture reaction can be used to uniquely identify neutrons in particle detectors. With the use of a capture-gated coincidence technique, the sequence of scatter events that lead to neutron thermalization prior to the neutron capture can also be used to measure neutron energy. We report on the measurement of thermalization light yield via a time-of-flight technique in a polyvinyl toluene-based scintillator EJ-290 within a heterogeneous composite detector that also includes 6Li-doped glass scintillator. The thermalization light output exhibits a strong correlation with neutron energy because of the preference for near-complete energy deposition prior to the 6Li(n,t)4He neutron capture reaction. The nonproportionality of the light yield from nuclear recoils contributes to the observed broadening of the distribution of thermalization light output. The nonproportional dependence of the scintillation light output in the EJ-290 scintillator as a function of proton recoil energy has been characterized in the range of 0.3–14.1 MeV via the Birks parametrization through a combination of time-of-flight measurement and previously conducted measurements with Monoenergetic neutron sources.

  18. Extraction and optical fluorescence method for the measurement of trace beryllium in soils.

    Science.gov (United States)

    Agrawal, Anoop; Cronin, John P; Agrawal, Akshay; Tonazzi, Juan C L; Adams, Lori; Ashley, Kevin; Brisson, Michael J; Duran, Brandy; Whitney, Gary; Burrell, Anthony K; McCleskey, T Mark; Robbins, James; White, Kenneth T

    2008-03-15

    Beryllium metal and beryllium oxide are important industrial materials used in a variety of applications in the electronics, nuclear energy, and aerospace industries. These materials are highly toxic, they must be disposed of with care, and exposed workers need to be protected. Recently, a new analytical method was developed that uses dilute ammonium bifluoride for extraction of beryllium and a high quantum yield optical fluorescence reagent to determine trace amounts of beryllium in airborne and surface samples. The sample preparation and analysis procedure was published by both ASTM International and the National Institute for Occupational Safety and Health (NIOSH). The main advantages of this method are its sensitivity, simplicity, use of lower toxicity materials, and low capital costs. Use of the technique for analyzing soils has been initiated to help meet a need at several of the U.S. Department of Energy legacy sites. So far this work has mainly concentrated on developing a dissolution protocol for effectively extracting beryllium from a variety of soils and sediments so that these can be analyzed by optical fluorescence. Certified reference materials (CRM) of crushed rock and soils were analyzed for beryllium content using fluorescence, and results agree quantitatively with reference values.

  19. Dicarboxy-dichlorofluorescein: a new fluorescent probe for measuring acidic intracellular pH.

    Science.gov (United States)

    Nedergaard, M; Desai, S; Pulsinelli, W

    1990-05-15

    Derivatives of fluorescein sensitive to pH are extensively utilized for the determination of intracellular pH (pHi). Available dyes have pKa values of approximately 7.0, and are not well suited for measuring acidic pHi. We examined the fluorescein derivative, 5 (and 6)-carboxy-2',7'-dichlorofluorescein (CDCF) for its potential in the microspectrofluorometric measurement of pHi during acidic conditions. CDCF showed intense fluorescence and pH sensitivity near its "effective" pKa value of 4.2, using a 495/440 nm dual excitation wave-length ratio method. Protein interactions caused fluorescence ratio deviations which were most pronounced at the extremes of pH, whereas calcium and magnesium concentrations had little effect on the fluorescent ratio intensity. Intracellular calibration performed using nigericin in the presence of high potassium eliminated the need to correct for protein interactions, and the ratio method minimized any variations due to dye concentration differences or instrument fluctuation. Intracellular retention of the dye was high, and 95% of the initial signal remained after 1 h. Fluorescence bleaching was 14.5% after 1 h of continuous excitation and cell survival was not affected by dye loading. We conclude that CDCF is an excellent intracellular pH indicator in the pH range of 4-5.

  20. Measurement of drug-target engagement in live cells by two-photon fluorescence anisotropy imaging.

    Science.gov (United States)

    Vinegoni, Claudio; Fumene Feruglio, Paolo; Brand, Christian; Lee, Sungon; Nibbs, Antoinette E; Stapleton, Shawn; Shah, Sunil; Gryczynski, Ignacy; Reiner, Thomas; Mazitschek, Ralph; Weissleder, Ralph

    2017-07-01

    The ability to directly image and quantify drug-target engagement and drug distribution with subcellular resolution in live cells and whole organisms is a prerequisite to establishing accurate models of the kinetics and dynamics of drug action. Such methods would thus have far-reaching applications in drug development and molecular pharmacology. We recently presented one such technique based on fluorescence anisotropy, a spectroscopic method based on polarization light analysis and capable of measuring the binding interaction between molecules. Our technique allows the direct characterization of target engagement of fluorescently labeled drugs, using fluorophores with a fluorescence lifetime larger than the rotational correlation of the bound complex. Here we describe an optimized protocol for simultaneous dual-channel two-photon fluorescence anisotropy microscopy acquisition to perform drug-target measurements. We also provide the necessary software to implement stream processing to visualize images and to calculate quantitative parameters. The assembly and characterization part of the protocol can be implemented in 1 d. Sample preparation, characterization and imaging of drug binding can be completed in 2 d. Although currently adapted to an Olympus FV1000MPE microscope, the protocol can be extended to other commercial or custom-built microscopes.

  1. Laser-induced fluorescence measurements on CdSe quantum dots

    Directory of Open Access Journals (Sweden)

    Zoltan Győri

    2010-03-01

    Full Text Available In this paper, we report on photoluminescence decay measurements on CdSe quantum dots (QDs as a function of size in the diameter range of 2.1 to 3.5 nm. The nanoparticles were synthesized by the kinetic growth method from CdO and elemental Se precursors. We studied the effects of growth time on the diameter, emission spectrum and the fluorescence lifetime of the synthesized QDs. The decay time measurements were performed using single shot time-resolved laser-induced fluorescence techniques using a Nd:YAG laser system. Two different decay times were measured on each CdSe sample, a fast one and a relatively slow one. The slow decay was found to be size dependent whereas the fast one was independent of the QD diameter.

  2. Spatially resolved density and ionization measurements of shocked foams using x-ray fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    MacDonald, M. J.; Keiter, P. A.; Montgomery, D. S.; Scott, H. A.; Biener, M. M.; Fein, J. R.; Fournier, K. B.; Gamboa, E. J.; Kemp, G. E.; Klein, S. R.; Kuranz, C. C.; LeFevre, H. J.; Manuel, M. J. -E.; Wan, W. C.; Drake, R. P.

    2016-09-28

    We present experiments at the Trident laser facility demonstrating the use of x-ray fluorescence (XRF) to simultaneously measure density, ionization state populations, and electron temperature in shocked foams. An imaging x-ray spectrometer obtained spatially resolved measurements of Ti K-α emission. Density profiles were measured from K-α intensity. Ti ionization state distributions and electron temperatures were inferred by fitting K-α spectra to spectra from CRETIN simulations. This work shows that XRF provides a powerful tool to complement other diagnostics to make equation of state measurements of shocked materials containing a suitable tracer element.

  3. Concentration Measurements in a Cold Flow Model Annular Combustor Using Laser Induced Fluorescence

    Science.gov (United States)

    Morgan, Douglas C.

    1996-01-01

    A nonintrusive concentration measurement method is developed for determining the concentration distribution in a complex flow field. The measurement method consists of marking a liquid flow with a water soluble fluorescent dye. The dye is excited by a two dimensional sheet of laser light. The fluorescent intensity is shown to be proportional to the relative concentration level. The fluorescent field is recorded on a video cassette recorder through a video camera. The recorded images are analyzed with image processing hardware and software to obtain intensity levels. Mean and root mean square (rms) values are calculated from these intensity levels. The method is tested on a single round turbulent jet because previous concentration measurements have been made on this configuration by other investigators. The previous results were used to comparison to qualify the current method. These comparisons showed that this method provides satisfactory results. 'Me concentration measurement system was used to measure the concentrations in the complex flow field of a model gas turbine annular combustor. The model annular combustor consists of opposing primary jets and an annular jet which discharges perpendicular to the primary jets. The mixing between the different jet flows can be visualized from the calculated mean and rms profiles. Concentration field visualization images obtained from the processing provide further qualitative information about the flow field.

  4. Characterization of a Be(p,xn) neutron source for fission yields measurements

    CERN Document Server

    Mattera, A; Hjalmarsson, A; Lantz, M; Pomp, S; Rakopoulos, V; Solders, A; Valldor-Blücher, J; Gorelov, D; Penttilä, H; Rinta-Antila, S; Prokofiev, A V; Passoth, E; Bedogni, R; Gentile, A; Bortot, D; Esposito, A; Introini, M V; Pola, A

    2013-01-01

    We report on measurements performed at The Svedberg Laboratory (TSL) to characterize a proton-neutron converter for independent fission yield studies at the IGISOL-JYFLTRAP facility (Jyv\\"askyl\\"a, Finland). A 30 MeV proton beam impinged on a 5 mm water-cooled Beryllium target. Two independent experimental techniques have been used to measure the neutron spectrum: a Time of Flight (TOF) system used to estimate the high-energy contribution, and a Bonner Sphere Spectrometer able to provide precise results from thermal energies up to 20 MeV. An overlap between the energy regions covered by the two systems will permit a cross-check of the results from the different techniques. In this paper, the measurement and analysis techniques will be presented together with some preliminary results.

  5. Surface Coverage and Structure of Mixed DNA/Alkylthiol Monolayers on Gold: Characterization by XPS, NEXAFS, and Fluorescence Intensity Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Lee,C.; Gong, P.; Harbers, G.; Grainger, D.; Castner, D.; Gamble, L.

    2006-01-01

    Self-assembly of thiol-terminated single-stranded DNA (HS-ssDNA) on gold has served as an important model system for DNA immobilization at surfaces. Here, we report a detailed study of the surface composition and structure of mixed self-assembled DNA monolayers containing a short alkylthiol surface diluent [11-mercapto-1-undecanol (MCU)] on gold supports. These mixed DNA monolayers were studied with X-ray photoelectron spectroscopy (XPS), near-edge X-ray absorption fine structure spectroscopy (NEXAFS), and fluorescence intensity measurements. XPS results on sequentially adsorbed DNA/MCU monolayers on gold indicated that adsorbed MCU molecules first incorporate into the HS-ssDNA monolayer and, upon longer MCU exposures, displace adsorbed HS-ssDNA molecules from the surface. Thus, HS-ssDNA surface coverage steadily decreased with MCU exposure time. Polarization-dependent NEXAFS and fluorescence results both show changes in signals consistent with changes in DNA orientation after only 30 min of MCU exposure. NEXAFS polarization dependence (followed by monitoring the N 1s{yields}{pi}* transition) of the mixed DNA monolayers indicated that the DNA nucleotide base ring structures are oriented more parallel to the gold surface compared to DNA bases in pure HS-ssDNA monolayers. This indicates that HS-ssDNA oligomers reorient toward a more-upright position upon MCU incorporation. Fluorescence intensity results using end-labeled DNA probes on gold show little observable fluorescence on pure HS-ssDNA monolayers, likely due to substrate quenching effects between the fluorophore and the gold. MCU diluent incorporation into HS-ssDNA monolayers initially increases DNA fluorescence signal by densifying the chemisorbed monolayer, prompting an upright orientation of the DNA, and moving the terminal fluorophore away from the substrate. Immobilized DNA probe density and DNA target hybridization in these mixed DNA monolayers, as well as effects of MCU diluent on DNA hybridization in

  6. [On-site measurement of landfill gas yield and verification of IPCC model].

    Science.gov (United States)

    Luo, Yu-Xiang; Wang, Wei; Gao, Xing-Bao

    2009-11-01

    In order to obtain the accurate yield of landfill gas in Yulongkeng Landfill, Shenzhen, improved pumping test was conducted. The methane production rates of the influence region were figured out as 14.67 x 10(-5), 9.46 x 10(-5), 9.55 x 10(-5), and 4.28 x 10(-5) m3/(t x h), respectively. According to the methane production rate, the whole methane yield of Yulongkeng Landfill in 2005 was 322 m3/h, which indicated that Yulongkeng Landfill had went into stationary phase and the recycle of landfill gas was not valuable. IPCC model was verified by the measured data. Degradation half life of the waste was the key parameter concerned to the prediction accuracy of IPCC model. In China, the degradable waste in municipal solid waste was mainly kitchen waste leading to a short degradation period, which caused the degradation half life was shorter than the proposed value in IPCC model. For the improvement in prediction accuracy of landfill gas yield, the model parameters should be adopted reasonably based on a full survey of waste characterization in China, which will boost the applicability of IPCC model.

  7. Measurements of DT and DD neutron yields by neutron activation on TFTR

    Energy Technology Data Exchange (ETDEWEB)

    Barnes, C.W.; Larson, A.R. [Los Alamos National Lab., NM (United States); LeMunyan, G. [Princeton Univ., NJ (United States). Plasma Physics Lab.; Loughlin, M.J. [JET Joint Undertaking, Abingdon (United Kingdom)

    1995-03-01

    A variety of elemental foils have been activated by neutron fluence from TFTR under conditions with the DT neutron yield per shot ranging from 10{sup 12} to over 10{sup 18}, and with the DT/(DD+DT) neutron ratio varying from 0.5% (from triton burnup) to unity. Linear response over this large dynamic range is obtained by reducing the mass of the foils and increasing the cooling time, all while accepting greatly improved counting statistics. Effects on background gamma-ray lines from foil-capsule-material contaminants, and the resulting lower limits on activation foil mass, have been determined. DT neutron yields from dosimetry standard reactions on aluminum, chromium, iron, nickel, zirconium, and indium are in agreement within the {+-}9% (one-sigma) accuracy of the measurements; also agreeing are yields from silicon foils using the ACTL library cross-section, while the ENDF/B-V library has too low a cross-section. Preliminary results from a variety of other threshold reactions are presented. Use of the {sup 115}In(n.n{prime}) {sup 115m}In reaction (0.42 times as sensitive to DT neutrons as DD neutrons) in conjunction with pure-DT reactions allows a determination of the DT/(DD+DT) ratio in trace tritium or low-power tritium beam experiments.

  8. Optimal replacement policies for dairy cows based on daily yield measurements

    DEFF Research Database (Denmark)

    Nielsen, Lars Relund; Jørgensen, Erik; Kristensen, Anders Ringgaard;

    2010-01-01

    describes the first step of developing an MDP model that can be integrated into a modern herd management system. A hierarchical MDP was formulated for the dairy cow replacement problem with stage lengths of 1 d. It can be used to assist the farmer in replacement decisions on a daily basis and is based...... on daily milk yield measurements that are available in modern milking systems. Bayesian updating was used to predict the performance of each cow in the herd and economic decisions were based on the prediction. Moreover, parameters in the model were estimated using data records of the specific herd under...

  9. Measurement of the isomeric yield ratios of fission products with JYFLTRAP

    CERN Document Server

    Gorelov, D; Hakala, J; Jokinen, A; Kolhinen, V S; Koponen, J; Lantz, M; Matteram, A; Moore, I; Penttilä, H; Pohjalainen, I; Pomp, S; Rakopoulos, V; Reponen, M; Rinta-Antilav, S; Schonnenschein, V; Simutkin, V; Solders, A; Voss, A; Äystö, J

    2014-01-01

    Several isomeric yield ratios of fission products in 25 MeV pr oton-induced fis- sion of 238 U were measured recently at the JYFLTRAP facility. The ion-g uide separator on-line method was utilized to produce radioacti ve ions. The dou- ble Penning-trap mass spectrometer was used to separate iso meric and ground states by their masses. To verify the new experimental techn ique γ -spectro- scopy method was used to obtain the same isomeric ratios.

  10. Measurement of neutron yield by 62 MeV proton beam on a thick Beryllium target

    CERN Document Server

    Alba, R; Boccaccio, P; Celentano, A; Colonna, N; Cosentino, G; Del Zoppo, A; Di Pietro, A; Esposito, J; Figuera, P; Finocchiaro, P; Kostyukov, A; Maiolino, C; Osipenko, M; Ricco, G; Ripani, M; Viberti, C M; Santonocito, D; Schillaci, M

    2012-01-01

    In the framework of research on IVth generation reactors and high intensity neutron sources a low-power prototype neutron amplifier was recently proposed by INFN. It is based on a low-energy, high current proton cyclotron, whose beam, impinging on a thick Beryllium converter, produces a fast neutron spectrum. The world database on the neutron yield from thick Beryllium target in the 70 MeV proton energy domain is rather scarce. The new measurement was performed at LNS, covering a wide angular range from 0 to 150 degrees and an almost complete neutron energy interval. In this contribution the preliminary data are discussed together with the proposed ADS facility.

  11. An Intelligent Optical Dissolved Oxygen Measurement Method Based on a Fluorescent Quenching Mechanism

    Directory of Open Access Journals (Sweden)

    Fengmei Li

    2015-12-01

    Full Text Available Dissolved oxygen (DO is a key factor that influences the healthy growth of fishes in aquaculture. The DO content changes with the aquatic environment and should therefore be monitored online. However, traditional measurement methods, such as iodometry and other chemical analysis methods, are not suitable for online monitoring. The Clark method is not stable enough for extended periods of monitoring. To solve these problems, this paper proposes an intelligent DO measurement method based on the fluorescence quenching mechanism. The measurement system is composed of fluorescent quenching detection, signal conditioning, intelligent processing, and power supply modules. The optical probe adopts the fluorescent quenching mechanism to detect the DO content and solves the problem, whereas traditional chemical methods are easily influenced by the environment. The optical probe contains a thermistor and dual excitation sources to isolate visible parasitic light and execute a compensation strategy. The intelligent processing module adopts the IEEE 1451.2 standard and realizes intelligent compensation. Experimental results show that the optical measurement method is stable, accurate, and suitable for online DO monitoring in aquaculture applications.

  12. Fluorescence lifetime measurement with confocal endomicroscopy for direct analysis of tissue biochemistry in vivo

    Directory of Open Access Journals (Sweden)

    Youngjae Won

    2016-08-01

    Full Text Available Confocal endomicroscopy is a powerful tool for in vivo real-time imaging at cellular resolution inside a living body without tissue resection. Microscopic fluorescence lifetime measurement can provide information about localized biochemical conditions such as pH and the concentrations of oxygen and calcium. We hypothesized that combining these techniques could assist accurate cancer discrimination by providing both biochemical and morphological information. We designed a dual-mode experimental setup for confocal endomicroscopic imaging and fluorescence lifetime measurement and applied it to a mouse xenograft model of activated human pancreatic cancer generated by subcutaneous injection of AsPC-1 tumor cells. Using this method with pH-sensitive sodium fluorescein injection, we demonstrated discrimination between normal and cancerous tissues in a living mouse. With further development, this method may be useful for clinical cancer detection.

  13. Measuring evaporation rates of laser-trapped droplets by use of fluorescent morphology-dependent resonances.

    Science.gov (United States)

    Pastel, R; Struthers, A

    2001-05-20

    Morphology-dependent resonances (MDRs) are used to measure accurately the evaporation rates of laser-trapped 1- to 2-mum droplets of ethylene glycol. Droplets containing 3 x 10(-5) M Rhodamine-590 laser dye are optically trapped in a 20-mum hollow fiber by two counterpropagating 150-mW, 800-nm laser beams. A weaker 532-nm laser excites the dye, and fluorescence emission is observed near 560 nm as the droplet evaporates. A complete series of first-order TE and TM MDRs dominates the fluorescent output. MDR mode identification sizes the droplets and provides accurate evaporation rates. We verify the automated MDR mode identification by counting fringes in a videotape of the experiment. The longitudinal spring constant of the trap, measured by analysis of the videotaped motion of droplets perturbed from the trap center, provides independent verification of the laser's intensity within the trap.

  14. 3D printed miniaturized spectral system for tissue fluorescence lifetime measurements

    Science.gov (United States)

    Zou, Luwei; Mahmoud, Mohamad; Fahs, Mehdi; Liu, Rui; Lo, Joe F.

    2016-04-01

    Various types of collagens, e.g. type I and III, represent the main load-bearing components in biological tissues. Their composition changes during processes like wound healing and fibrosis. Collagens exhibit autofluorescence when excited by ultra-violet light, distinguishable by their unique fluorescent lifetimes across a range of emission wavelengths. Therefore, we designed a miniaturized spectral-lifetime detection system for collagens as a non-invasive probe for monitoring tissue in wound healing and scarring applications. A sine modulated LED illumination was applied to enable frequency domain (FD) fluorescence lifetime measurements under different wavelengths bands, separated via a series of longpass dichroics at 387nm, 409nm and 435nm. To achieve the minute scale of optomechanics, we employed a stereolithography based 3D printer with types were measured, where the separate spectral bands enhanced the differentiation of their lifetimes.

  15. A Method to Reconstruct the Solar-Induced Canopy Fluorescence Spectrum from Hyperspectral Measurements

    Directory of Open Access Journals (Sweden)

    Feng Zhao

    2014-10-01

    Full Text Available A method for canopy Fluorescence Spectrum Reconstruction (FSR is proposed in this study, which can be used to retrieve the solar-induced canopy fluorescence spectrum over the whole chlorophyll fluorescence emission region from 640–850 nm. Firstly, the radiance of the solar-induced chlorophyll fluorescence (Fs at five absorption lines of the solar spectrum was retrieved by a Spectral Fitting Method (SFM. The Singular Vector Decomposition (SVD technique was then used to extract three basis spectra from a training dataset simulated by the model SCOPE (Soil Canopy Observation, Photochemistry and Energy fluxes. Finally, these basis spectra were linearly combined to reconstruct the Fs spectrum, and the coefficients of them were determined by Weighted Linear Least Squares (WLLS fitting with the five retrieved Fs values. Results for simulated datasets indicate that the FSR method could accurately reconstruct the Fs spectra from hyperspectral measurements acquired by instruments of high Spectral Resolution (SR and Signal to Noise Ratio (SNR. The FSR method was also applied to an experimental dataset acquired in a diurnal experiment. The diurnal change of the reconstructed Fs spectra shows that the Fs radiance around noon was higher than that in the morning and afternoon, which is consistent with former studies. Finally, the potential and limitations of this method are discussed.

  16. Dual-fission chamber and neutron beam characterization for fission product yield measurements using monoenergetic neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Bhatia, C.; Fallin, B. [Department of Physics, Duke University, Durham, NC 27708 (United States); Triangle Universities Nuclear Laboratory, Durham, NC 27708 (United States); Gooden, M.E., E-mail: megooden@tunl.duke.edu [Triangle Universities Nuclear Laboratory, Durham, NC 27708 (United States); Department of Physics, North Carolina State University, Raleigh, NC 27605 (United States); Howell, C.R. [Department of Physics, Duke University, Durham, NC 27708 (United States); Triangle Universities Nuclear Laboratory, Durham, NC 27708 (United States); Kelley, J.H. [Triangle Universities Nuclear Laboratory, Durham, NC 27708 (United States); Department of Physics, North Carolina State University, Raleigh, NC 27605 (United States); Tornow, W. [Department of Physics, Duke University, Durham, NC 27708 (United States); Triangle Universities Nuclear Laboratory, Durham, NC 27708 (United States); Arnold, C.W.; Bond, E.M.; Bredeweg, T.A.; Fowler, M.M.; Moody, W.A.; Rundberg, R.S.; Rusev, G.; Vieira, D.J.; Wilhelmy, J.B. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Becker, J.A.; Macri, R.; Ryan, C.; Sheets, S.A.; Stoyer, M.A. [Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States); and others

    2014-09-01

    A program has been initiated to measure the energy dependence of selected high-yield fission products used in the analysis of nuclear test data. We present out initial work of neutron activation using a dual-fission chamber with quasi-monoenergetic neutrons and gamma-counting method. Quasi-monoenergetic neutrons of energies from 0.5 to 15 MeV using the TUNL 10 MV FM tandem to provide high-precision and self-consistent measurements of fission product yields (FPY). The final FPY results will be coupled with theoretical analysis to provide a more fundamental understanding of the fission process. To accomplish this goal, we have developed and tested a set of dual-fission ionization chambers to provide an accurate determination of the number of fissions occurring in a thick target located in the middle plane of the chamber assembly. Details of the fission chamber and its performance are presented along with neutron beam production and characterization. Also presented are studies on the background issues associated with room-return and off-energy neutron production. We show that the off-energy neutron contribution can be significant, but correctable, while room-return neutron background levels contribute less than <1% to the fission signal.

  17. Evaluation of Portable X-Ray Fluorescence (XRF) Analyzer for Zirconium-Thickness Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Glenn Moore

    2013-09-01

    This Technical Evaluation Report provides details of preliminary testing/experiments performed using a handheld X-ray fluorescence analyzer. The analyzer will be utilized in upcoming fuel-foil-rolling optimization studies at the INL. The studies are being performed in support of DOE’s Office of Global Threat Reduction -- Reactor Conversion Subprogram. Details of the equipment used, operating parameters, and measurement results are provided in this report.

  18. Measurement of R Line Fluorescence in Ruby Using the Diamond Anvil Cell at Low Temperature

    Institute of Scientific and Technical Information of China (English)

    XU Li-Wen; CHE Rong-Zheng; JIN Chang-Qing

    2000-01-01

    Using our custom-built high-pressure cryostat we have performed the measurements of the R line fluorescence of ruby in the diamond anvil cell from room temperature down to 90K. The maximum pressure was 11.1 GPa. By computer curve fitting, different equations have been found for functions of wavenumber versus temperature between ambient pressure and 2.7 GPa. The changes of the shape and linewidth of R lines were observed.

  19. Methodology for the use of proportional counters in pulsed fast neutron yield measurements

    CERN Document Server

    Tarifeño-Saldivia, Ariel; Pavez, Cristian; Soto, Leopoldo

    2011-01-01

    This paper introduces in full detail a methodology for the measurement of neutron yield and the necessary efficiency calibration, to be applied to the intensity measurement of neutron bursts where individual neutrons are not resolved in time, for any given moderated neutron proportional counter array. The method allows efficiency calibration employing the detection neutrons arising from an isotopic neutron source. Full statistical study of the procedure is descripted, taking into account contributions arising from counting statistics, piling-up statistics of real detector pulse-height spectra and background fluctuations. The useful information is extracted from the net waveform area of the signal arising from the electric charge accumulated inside the detector tube. Improvement of detection limit is gained, therefore this detection system can be used in detection of low emission neutron pulsed sources with pulses of duration from nanoseconds to up. The application of the methodology to detection systems to be...

  20. A fluorescence anisotropy method for measuring protein concentration in complex cell culture media.

    Science.gov (United States)

    Groza, Radu Constantin; Calvet, Amandine; Ryder, Alan G

    2014-04-22

    The rapid, quantitative analysis of the complex cell culture media used in biopharmaceutical manufacturing is of critical importance. Requirements for cell culture media composition profiling, or changes in specific analyte concentrations (e.g. amino acids in the media or product protein in the bioprocess broth) often necessitate the use of complicated analytical methods and extensive sample handling. Rapid spectroscopic methods like multi-dimensional fluorescence (MDF) spectroscopy have been successfully applied for the routine determination of compositional changes in cell culture media and bioprocess broths. Quantifying macromolecules in cell culture media is a specific challenge as there is a need to implement measurements rapidly on the prepared media. However, the use of standard fluorescence spectroscopy is complicated by the emission overlap from many media components. Here, we demonstrate how combining anisotropy measurements with standard total synchronous fluorescence spectroscopy (TSFS) provides a rapid, accurate quantitation method for cell culture media. Anisotropy provides emission resolution between large and small fluorophores while TSFS provides a robust measurement space. Model cell culture media was prepared using yeastolate (2.5 mg mL(-1)) spiked with bovine serum albumin (0 to 5 mg mL(-1)). Using this method, protein emission is clearly discriminated from background yeastolate emission, allowing for accurate bovine serum albumin (BSA) quantification over a 0.1 to 4.0 mg mL(-1) range with a limit of detection (LOD) of 13.8 μg mL(-1). Copyright © 2014. Published by Elsevier B.V.

  1. Oxygen plasma flow properties deduced from laser-induced fluorescence and probe measurements

    Science.gov (United States)

    Löhle, Stefan; Eichhorn, Christoph; Steinbeck, Andreas; Lein, Sebastian; Herdrich, Georg; Röser, Hans-Peter; Auweter-Kurtz, Monika

    2008-04-01

    Estimation of the local dissociation degree and the local mass-specific enthalpy of a pure oxygen plasma flow determined mainly from laser-induced fluorescence measurements are reported. Measurements have been conducted for several generator parameters in an inductively heated plasma wind tunnel. Additional probe measurements of total pressure together with the deduced translational temperature are used to estimate the local mass-specific enthalpy. For a reference condition, full dissociation has been measured. The measured translational temperature of atomic oxygen for this condition is T = 3500 K. Subsequently, the local mass-specific enthalpy has been derived using these local density and temperature measurements. For the reference condition the estimated value of h = 27 MJ/kg is in good agreement with the probe measurements and results from diode laser absorption spectroscopy.

  2. Synthesis of Novel Hyperbranched Polybenzo-Bisthiazole Amide with Donor–Acceptor (D-A Architecture, High Fluorescent Quantum Yield and Large Stokes Shift

    Directory of Open Access Journals (Sweden)

    Xiaobing Hu

    2017-07-01

    Full Text Available Two novel highly fluorescent hyperbranched polybenzobisthiazole amides with a donor–acceptor architecture and large Stokes shift were rationally designed and synthesized. The chemical structures of the prepared hyperbranched polymers were characterized using Fourier Transform Infrared Spectroscopy (FTIR analysis, Hydrogen Nuclear Magnetic Resonance (1H-NMR analysis, and Gel Permeation Chromatography (GPC analysis. These two polymers were soluble in dimethyl sulfoxide (DMSO and N,N-dimethylformamide (DMF, and their DMSO and DMF solutions emitted strong green light (517–537 nm with high quantum yields (QYs and large Stokes shifts. Their relative fluorescence QYs in the DMSO solution were calculated as 77.75% and 81.14% with the Stokes shifts of 137 nm (0.86 eV and 149 nm (0.92 eV for HP–COOH and HP–NH2, respectively, using quinine sulfate as the standard. In the DMF solution, the QYs of HP–COOH and HP–NH2 were calculated as 104.65% and 118.72%, with the Stokes shifts of 128 nm (0.79 eV and 147 nm (0.87 eV, respectively. Their films mainly emitted strong blue light with the maximum emission wavelengths of 436 nm and 480 nm for HP–COOH and HP–NH2, respectively. The Stokes shifts for HP–COOH and HP–NH2 films were 131 nm (0.42 eV and 179 nm (0.86 eV, respectively. They are promising candidates for luminescent solar concentrators and blue light emitting materials.

  3. The Effects of Opaque and Clear Pit and Fissure Sealants on Infrared Laser Fluorescence Measurements

    Science.gov (United States)

    Bahrololoomi, Z.; Khodabakhsh, M.; Khaksar, Y.

    2014-01-01

    Statement of the Problem: The purpose of placing sealants is to inhibit caries by physical closure of the pits and fissures of teeth. A device named DIAGNOdent is useful in detecting occlusal caries by employing laser fluorescence (LF). However, there are contradictory results in the influence of sealants on LF measurements. Purpose: The aim of this study is to investigate the effects of two different types of fissure sealants on LF measurements. Materials and Method: In this in vitro study, 86 extracted permanent third molars were divided randomly into two groups and clear or opaque sealant was applied on the occlusal surfaces. Two examiners performed pre- and post-seal fluorescence measurements twice with one week interval by employing DIAGNOdent device. Finally, measured values were evaluated through the statistical paired t-test by means of SPSS 17 software. Results: The mean value of LF measurements increased significantly due to the application of clear sealant (p= 0.001) while the statistical changes in this measurement was negligible after applying opaque sealant (p= 0.311). Conclusion: Clear sealants increase the LF measured values but opaque sealants cause almost no changes. Therefore, DIAGNOdent device is not reliable for detecting caries beneath the clear sealant. PMID:24883342

  4. The Effects of Opaque and Clear Pit and Fissure Sealants on Infrared Laser Fluorescence Measurements

    Directory of Open Access Journals (Sweden)

    Bahrololoomi Z.

    2013-10-01

    Full Text Available Statement of the Problem: The purpose of placing sealants is to inhibit caries by physical closure of the pits and fissures of teeth. A device named DIAGNOdent is useful in detecting occlusal caries by employing laser fluorescence (LF. However, there are contradictory results in the influence of sealants on LF measurements. Purpose: The aim of this study is to investigate the effects of two different types of fissure sealants on LF measurements. Materials and Method: In this in vitro study, 86 extracted permanent third molars were divided randomly into two groups and clear or opaque sealant was applied on the occlusal surfaces. Two examiners performed pre and post-seal fluorescence measurements twice with one week interval by employing DIAGNOdent device. Finally, measured values were evaluated through the statistical paired t-test by means of SPSS 17 software. Results: The mean value of LF measurements increased significantly due to the application of clear sealant (p= 0.001 while the statistical changes in this measurement is negligible after applying opaque sealant (p= 0.311. Conclusion: Clear sealants increase the LF measured values but opaque sealants cause almost no changes. Therefore DIAGNOdent device is not reliable for detecting caries beneath the clear sealant.

  5. Development and Validation of a Fluorescent Multiplexed Immunoassay for Measurement of Transgenic Proteins in Cotton (Gossypium hirsutum).

    Science.gov (United States)

    Yeaman, Grant R; Paul, Sudakshina; Nahirna, Iryna; Wang, Yongcheng; Deffenbaugh, Andrew E; Liu, Zi Lucy; Glenn, Kevin C

    2016-06-22

    In order to provide farmers with better and more customized alternatives to improve yields, combining multiple genetically modified (GM) traits into a single product (called stacked trait crops) is becoming prevalent. Trait protein expression levels are used to characterize new GM products and establish exposure limits, two important components of safety assessment. Developing a multiplexed immunoassay capable of measuring all trait proteins in the same sample allows for higher sample throughput and savings in both time and expense. Fluorescent (bead-based) multiplexed immunoassays (FMI) have gained wide acceptance in mammalian research and in clinical applications. In order to facilitate the measurement of stacked GM traits, we have developed and validated an FMI assay that can measure five different proteins (β-glucuronidase, neomycin phosphotransferase II, Cry1Ac, Cry2Ab2, and CP4 5-enolpyruvyl-shikimate-3-phosphate synthase) present in cotton leaf from a stacked trait product. Expression levels of the five proteins determined by FMI in cotton leaf tissues have been evaluated relative to expression levels determined by enzyme-linked immunosorbent assays (ELISAs) of the individual proteins and shown to be comparable. The FMI met characterization requirements similar to those used for ELISA. Therefore, it is reasonable to conclude that FMI results are equivalent to those determined by conventional individual ELISAs to measure GM protein expression levels in stacked trait products but with significantly higher throughput, reduced time, and more efficient use of resources.

  6. A measurement of R{sub b} = {Gamma}(Z{sup 0} {yields} b{bar b})/{Gamma}(Z{sup 0} {yields} hadrons) at SLD

    Energy Technology Data Exchange (ETDEWEB)

    SLD Collaboration

    1993-09-01

    A measurement of the ratio R{sub b} = {Gamma}(Z{sup 0} {yields} b{bar b})/{Gamma}(Z{sup 0} {yields} hadrons) is reported. This measurement is made using the CCD-based vertex detector of the SLD detector at the SLAC Linear Collider. Efficient tagging of b{bar b} events is performed with an impact parameter technique that takes advantage of the small and stable interaction point of the SLC and all charged tracks in Z{sup 0} decays. In a sample of 27K Z{sup 0} events, a value R{sub b}=0.235{plus_minus}0.006{plus_minus}0.018 is obtained.

  7. The neutron-proton charge-exchange amplitudes measured in the dp {yields} ppn reaction

    Energy Technology Data Exchange (ETDEWEB)

    Mchedlishvili, D.; Chiladze, D. [Tbilisi State University, High Energy Physics Institute, Tbilisi (Georgia); Forschungszentrum Juelich, Institut fuer Kernphysik and Juelich Centre for Hadron Physics, Juelich (Germany); Barsov, S.; Dzyuba, A. [Petersburg Nuclear Physics Institute, High Energy Physics Department, Gatchina (Russian Federation); Carbonell, J. [Universite Paris-Sud, IN2P3-CNRS, Institut de Physique Nucleaire, Orsay Cedex (France); Dymov, S. [JINR, Laboratory of Nuclear Problems, Dubna (Russian Federation); Universitaet Erlangen-Nuernberg, Physikalisches Institut II, Erlangen (Germany); Engels, R.; Gebel, R.; Hartmann, M.; Kacharava, A.; Kamerdzhiev, V.; Lehrach, A.; Lorentz, B.; Maier, R.; Ohm, H.; Prasuhn, D.; Rathmann, F.; Serdyuk, V.; Seyfarth, H.; Stein, H.J.; Stockhorst, H.; Stroeher, H. [Forschungszentrum Juelich, Institut fuer Kernphysik and Juelich Centre for Hadron Physics, Juelich (Germany); Glagolev, V. [JINR, Laboratory of High Energies, Dubna (Russian Federation); Grigoryev, K.; Mikirtychyants, M.; Mikirtychyants, S.; Valdau, Yu. [Forschungszentrum Juelich, Institut fuer Kernphysik and Juelich Centre for Hadron Physics, Juelich (Germany); Petersburg Nuclear Physics Institute, High Energy Physics Department, Gatchina (Russian Federation); Goslawski, P.; Khoukaz, A.; Mielke, M.; Papenbrock, M. [Universitaet Muenster, Institut fuer Kernphysik, Muenster (Germany); Keshelashvili, I. [Tbilisi State University, High Energy Physics Institute, Tbilisi (Georgia); University of Basel, Department of Physics, Basel (Switzerland); Komarov, V.; Kulikov, A. [JINR, Laboratory of Nuclear Problems, Dubna (Russian Federation); Kulessa, P. [H. Niewodniczanski Institute of Nuclear Physics PAN, Krakow (Poland); Lomidze, N.; Nioradze, M.; Tabidze, M. [Tbilisi State University, High Energy Physics Institute, Tbilisi (Georgia); Macharashvili, G. [Tbilisi State University, High Energy Physics Institute, Tbilisi (Georgia); JINR, Laboratory of Nuclear Problems, Dubna (Russian Federation); Merzliakov, S. [Forschungszentrum Juelich, Institut fuer Kernphysik and Juelich Centre for Hadron Physics, Juelich (Germany); JINR, Laboratory of Nuclear Problems, Dubna (Russian Federation); Steffens, E. [Universitaet Erlangen-Nuernberg, Physikalisches Institut II, Erlangen (Germany); Trusov, S. [Forschungszentrum Rossendorf, Institut fuer Kern- und Hadronenphysik, Dresden (Germany); Uzikov, Yu. [JINR, Laboratory of Nuclear Problems, Dubna (Russian Federation); M. V. Lomonosov Moscow State University, Department of Physics, Moscow (Russian Federation); Wilkin, C. [UCL, Physics and Astronomy Department, London (United Kingdom)

    2013-04-15

    The unpolarised differential cross section and the two deuteron tensor analysing powers A{sub xx} and A{sub yy} of the vector dp {yields} {l_brace}pp{r_brace}{sub s}n charge-exchange reaction have been measured with the ANKE spectrometer at the COSY storage ring. Using deuteron beams with energies 1.2, 1.6, 1.8, and 2.27GeV, data were obtained for small momentum transfers to a {l_brace}pp{r_brace}{sub s} system with low excitation energy. The results at the three lower energies are consistent with impulse approximation predictions based upon the current knowledge of the neutron-proton amplitudes. However, at 2.27GeV, where these amplitudes are far more uncertain, agreement requires a reduction in the overall double-spin-flip contribution, with an especially significant effect in the longitudinal direction. These conclusions are supported by measurements of the deuteron-proton spin-correlation parameters C{sub x,x} and C{sub y,y} that were carried out in the vector dvector p {yields} {l_brace}pp{r_brace}{sub s}n reaction at 1.2 and 2.27GeV. The values obtained for the proton analysing power A{sub y}{sup p} also suggest the need for a radical re-evaluation of the neutron-proton elastic scattering amplitudes at the higher energy. It is therefore clear that such measurements can provide a valuable addition to the neutron-proton database in the charge-exchange region. (orig.)

  8. Resolution of heterogeneous fluorescence emission signals and decay lifetime measurement on fluorochrome-labeled cells by phase-sensitive FCM

    Energy Technology Data Exchange (ETDEWEB)

    Steinkamp, J.A.; Crissman, H.A.

    1993-02-01

    A phase-sensitive flow cytometer has been developed to resolve signals from heterogeneous fluorescence emission spectra and quantify fluorescence decay times on cells labeled with fluorescent dyes. This instrument combines flow cytometry (FCM) and fluorescence spectroscopy measurement principles to provide unique capabilities for making phase-resolved measurements on single cells in flow, while preserving conventional FCM measurement capabilities. Stained cells are analyzed as they pass through an intensity-modulated (sinusoid) laser excitation beam. Fluorescence is measured orthogonally using a s barrier filter to block scattered laser excitation light, and a photomultiplier tube detector output signals, which are shifted in phase from a reference signal and amplitude demodulated, are processed by phase-sensitive detection electronics to resolve signals from heterogeneous emissions and quantify decay lifetimes directly. The output signals are displayed as frequency distribution histograms and bivariate diagrams using a computer-based data acquisition system. Results have demonstrated signal phase shift, amplitude demodulation, and average measurement of fluorescence lifetimes on stained cells; a detection limit threshold of 300 to 500 fluorescein isothiocyanate (FITC); fluorescence measurement precision of 1.3% on alignment fluorospheres and 3.4% on propidium iodide (PI)-stained cells; the resolution of PI and FITC signals from cells stainedin combination with PI and FITC, based on differences in their decay lifetimes; and the ability to measure single decay nines by the two-phase, phase comparator, method.

  9. Resolution of heterogeneous fluorescence emission signals and decay lifetime measurement on fluorochrome-labeled cells by phase-sensitive FCM

    Energy Technology Data Exchange (ETDEWEB)

    Steinkamp, J.A.; Crissman, H.A.

    1993-01-01

    A phase-sensitive flow cytometer has been developed to resolve signals from heterogeneous fluorescence emission spectra and quantify fluorescence decay times on cells labeled with fluorescent dyes. This instrument combines flow cytometry (FCM) and fluorescence spectroscopy measurement principles to provide unique capabilities for making phase-resolved measurements on single cells in flow, while preserving conventional FCM measurement capabilities. Stained cells are analyzed as they pass through an intensity-modulated (sinusoid) laser excitation beam. Fluorescence is measured orthogonally using a s barrier filter to block scattered laser excitation light, and a photomultiplier tube detector output signals, which are shifted in phase from a reference signal and amplitude demodulated, are processed by phase-sensitive detection electronics to resolve signals from heterogeneous emissions and quantify decay lifetimes directly. The output signals are displayed as frequency distribution histograms and bivariate diagrams using a computer-based data acquisition system. Results have demonstrated signal phase shift, amplitude demodulation, and average measurement of fluorescence lifetimes on stained cells; a detection limit threshold of 300 to 500 fluorescein isothiocyanate (FITC); fluorescence measurement precision of 1.3% on alignment fluorospheres and 3.4% on propidium iodide (PI)-stained cells; the resolution of PI and FITC signals from cells stainedin combination with PI and FITC, based on differences in their decay lifetimes; and the ability to measure single decay nines by the two-phase, phase comparator, method.

  10. Comparison of plate reader-based methods with fluorescence microscopy for measurements of intracellular calcium levels for the assessment of in vitro neurotoxicity.

    Science.gov (United States)

    Meijer, Marieke; Hendriks, Hester S; Heusinkveld, Harm J; Langeveld, Wendy T; Westerink, Remco H S

    2014-12-01

    The intracellular calcium concentration ([Ca(2+)]i) is an important readout for in vitro neurotoxicity since calcium is critically involved in many essential neurobiological processes, including neurotransmission, neurodegeneration and neurodevelopment. [Ca(2+)]i is often measured with considerable throughput at the level of cell populations with plate reader-based assays or with lower throughput at the level of individual cells with fluorescence microscopy. However, these methodologies yield different quantitative and qualitative results. In recent years, we demonstrated that the resolution and sensitivity of fluorescence microscopy is superior compared to plate reader-based assays. However, it is currently unclear if the use of plate reader-based assays results in more 'false negatives' or 'false positives' in neurotoxicity screening studies. In the present study, we therefore compared a plate reader-based assay with fluorescence microscopy using a small test set of environmental pollutants consisting of dieldrin, lindane, polychlorinated biphenyl 53 (PCB53) and tetrabromobisphenol-A (TBBPA). Using single-cell fluorescence microscopy, we demonstrate that all test chemicals reduce the depolarization-evoked increase in [Ca(2+)]i, whereas lindane, PCB53 and TBBPA also increase basal [Ca(2+)]i, though via different mechanisms. Importantly, none of these effects were confirmed with the plate reader-based assay. We therefore conclude that standard plate reader-based methods are not sufficiently sensitive and reliable to measure the highly dynamic and transient changes in [Ca(2+)]i that occur during chemical exposure. Copyright © 2014 Elsevier Inc. All rights reserved.

  11. In-Situ Measurements of the Secondary Electron Yield in an Accelerator Environment: Instrumentation and Methods

    CERN Document Server

    Hartung, W H; Conway, J V; Dennett, C A; Greenwald, S; Kim, J -S; Li, Y; Moore, T P; Omanovic, V; Palmer, M A; Strohman, C R

    2014-01-01

    The performance of a particle accelerator can be limited by the build-up of an electron cloud (EC) in the vacuum chamber. Secondary electron emission from the chamber walls can contribute to EC growth. An apparatus for in-situ measurements of the secondary electron yield (SEY) in the Cornell Electron Storage Ring (CESR) was developed in connection with EC studies for the CESR Test Accelerator program. The CESR in-situ system, in operation since 2010, allows for SEY measurements as a function of incident electron energy and angle on samples that are exposed to the accelerator environment, typically 5.3 GeV counter-rotating beams of electrons and positrons. The system was designed for periodic measurements to observe beam conditioning of the SEY with discrimination between exposure to direct photons from synchrotron radiation versus scattered photons and cloud electrons. The samples can be exchanged without venting the CESR vacuum chamber. Measurements have been done on metal surfaces and EC-mitigation coatings...

  12. Nonlinear reconstruction of absorption and fluorescence contrast from measured diffuse transmittance and reflectance of a compressed-breast-simulating phantom.

    Science.gov (United States)

    Ziegler, Ronny; Nielsen, Tim; Koehler, Thomas; Grosenick, Dirk; Steinkellner, Oliver; Hagen, Axel; Macdonald, Rainer; Rinneberg, Herbert

    2009-08-20

    We report on the nonlinear reconstruction of local absorption and fluorescence contrast in tissuelike scattering media from measured time-domain diffuse reflectance and transmittance of laser as well as laser-excited fluorescence radiation. Measurements were taken at selected source-detector offsets using slablike diffusely scattering and fluorescent phantoms containing fluorescent heterogeneities. Such measurements simulate in vivo data that would be obtained employing a scanning, time-domain fluorescence mammograph, where the breast is gently compressed between two parallel glass plates, and source and detector optical fibers scan synchronously at various source-detector offsets, allowing the recording of laser and fluorescence mammograms. The diffusion equations modeling the propagation of the laser and fluorescence radiation were solved in frequency domain by the finite element method simultaneously for several modulation frequencies using Fourier transformation and preprocessed experimental data. To reconstruct the concentration of the fluorescent contrast agent, the Born approximation including higher-order reconstructed photon densities at the excitation wavelength was used. Axial resolution was determined that can be achieved by various detection schemes. We show that remission measurements increase the depth resolution significantly.

  13. "Open-Box" Approach to Measuring Fluorescence Quenching Using an iPad Screen and Digital SLR Camera

    Science.gov (United States)

    Koenig, Michael H.; Yi, Eun P.; Sandridge, Matthew J.; Mathew, Alexander S.; Demas, James N.

    2015-01-01

    Fluorescence quenching is an analytical technique and a common undergraduate laboratory exercise. Unfortunately, a typical quenching experiment requires the use of an expensive fluorometer that measures the relative fluorescence intensity of a single sample in a closed compartment unseen by the experimenter. To overcome these shortcomings, we…

  14. Dual wavelength fluorescent ratiometric pH measurement by scanning near-field optical microscopy

    Science.gov (United States)

    Li, Yongbo; Shinohara, Ryosuke; Iwami, Kentaro; Ohta, Yoshihiro; Umeda, Norihiro

    2010-08-01

    A novel method to observe pH distribution by dual wavelength fluorescent ratiometric pH measurement by scanning near-field optical microscopy (SNOM) is developed. In this method, in order to investigate not only the pH of mitochondrial membrane but also its distribution in the vicinity, a pH sensitive fluorescent reagent covers mitochondria instead of injecting it to mitochondria. This method utilizes a dual-emission pH sensitive dye and SNOM with a themally-pulled and metal-coated optical fiber to improve the spatial resolution. Time-dependence of Fluorescent intensity ratio (FIR) under acid addition is investigated. As the distances between the dropped point and the SNOM probe becomes closer, the time when FIR changes becomes earlier. The response of mitochondria under supplement of nutrition is studied by using this method. While the probe is near to mitochondria, the ratio quickly becomes to increase. In conclusion, it was confirmed that the temporal variation of pH can be detected by this method, and pH distribution in the vicinity of mitochondria is able to be measured by this method.

  15. A method of measuring gold nanoparticle concentrations by x-ray fluorescence for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Wu Di; Li Yuhua; Wong, Molly D.; Liu Hong [Center for Bioengineering and School of Electrical and Computer Engineering, University of Oklahoma, Norman, Oklahoma 73019 (United States)

    2013-05-15

    Purpose: This paper reports a technique that enables the quantitative determination of the concentration of gold nanoparticles (GNPs) through the accurate detection of their fluorescence radiation in the diagnostic x-ray spectrum. Methods: Experimentally, x-ray fluorescence spectra of 1.9 and 15 nm GNP solutions are measured using an x-ray spectrometer, individually and within chicken breast tissue samples. An optimal combination of excitation and emission filters is determined to segregate the fluorescence spectra at 66.99 and 68.80 keV from the background scattering. A roadmap method is developed that subtracts the scattered radiation (acquired before the insertion of GNP solutions) from the signal radiation acquired after the GNP solutions are inserted. Results: The methods effectively minimize the background scattering in the spectrum measurements, showing linear relationships between GNP solutions from 0.1% to 10% weight concentration and from 0.1% to 1.0% weight concentration inside a chicken breast tissue sample. Conclusions: The investigation demonstrated the potential of imaging gold nanoparticles quantitatively in vivo for in-tissue studies, but future studies will be needed to investigate the ability to apply this method to clinical applications.

  16. Phase discrimination inside a spray: LDV measurements using fluorescent seeding particles (FLDV)

    Energy Technology Data Exchange (ETDEWEB)

    Rottenkolber, G.; Meier, R.; Schaefer, O.; Dullenkopf, K.; Wittig, S. [Karlsruhe Univ. (T.H.) (Germany). Inst. fuer Thermische Stroemungsmaschinen; Wachter, S. [Karlsruhe Univ. (T.H.) (Germany). Inst. fuer Thermische Stroemungsmaschinen]|[Karlsruhe Univ. (T.H.) (Germany). Inst. fuer Angewandte Physik

    2002-07-01

    Laser Velocimetry measurements in the vicinity of reflecting surfaces are still a major problem in many fluid mechanical applications such as measuring close to walls or wall film surfaces, respectively. Moreover, in any kind of two phase flow an unambiguous separation of the gas and the liquid phase is of particular interest. Commonly used techniques like phase doppler analysers (PDA) with size discrimination are limited to two phase flows where the smallest particle of the dispersed phase is significantly larger than the seeding particles. This condition can rarely be fulfilled in technically relevant spray/air systems. One of the most promising approaches is a phase discrimination using fluorescent tracer particles for the gas phase. In this paper the working principle of the ''fluorescent'' LDV (FLDV) will be explained. Moreover, the applicability of different fluorescent dyes will be discussed. Finally, a comparison between PDA results using size discrimination and FLDV results inside a hollow come spray will be presented. (orig.)

  17. The photoneutron yield predictions by PICA and comparison with the measurements

    Energy Technology Data Exchange (ETDEWEB)

    Job, P.K. [Argonne National Lab., IL (United States); Gabriel, T.A. [Oak Ridge National Lab., TN (United States)

    1995-12-31

    The photoneutron yields at higher photon energies have become very important since the advent of high energy electron accelerators. Bremsstrahlung is produced when the particle beam interacts with the storage-ring components or residual-gas molecules in the storage-ring vacuum. Bremsstrahlung thus produced interacts with the high-Z materials in the beamline like the beam dumps and collimators to produce photoneutrons. There are three modes of neutron production by bremsstrahlung. At low energies ({>=}525 MeV), photons are absorbed by the dipole interaction and the compound nucleus thus formed decays emitting protons and neutrons and other heavier particles. At higher energies ({>=}25 MeV), photon interacts with the nucleus through absorption on a quasi-deuteron, which subsequently decays producing a neutron and proton pair which can interact with the rest of the nucleus. At still higher energies the photopion production becomes possible and competes with the quasi-deuteron process. In this paper we have calculated the photoneutron yield from a thick copper target using the photonuclear interaction code PICA. Using this as the neutron source, we have calculated the dose rates through heavy concrete and compared it with the measurements made at the Advanced Photon Source at Argonne National Lab.

  18. Determining a fluorophore's transition dipole moment from fluorescence lifetime measurements in solvents of varying refractive index.

    Science.gov (United States)

    Chung, Pei-Hua; Tregidgo, Carolyn; Suhling, Klaus

    2016-11-11

    The transition dipole moment of organic dyes PM546 and rhodamine 123 is calculated from fluorescence lifetime measurements in solutions of different refractive index. A model proposed by Toptygin et al (2002 J. Phys. Chem. B 106 3724-34) provides a relationship between the radiative rate constant and refractive index of the solvent, and allows the electronic transition dipole moments to be found: it is (7.1  ±  1.1) D for PM546 which matches that found in the literature, and (8.1  ±  0.1) D for rhodamine 123. Toptygin's model goes further in predicting the shape of the fluorescent dye and here we predict the shape of PM546 and rhodamine 123 to be ellipsoidal.

  19. Immobilized fluorescent dyes for sensitive pH measurements on enamel surfaces with fiber optics

    Science.gov (United States)

    Rumphorst, A.; Seeger, Stefan; Duschner, H.

    1996-01-01

    Information on the pH directly on surfaces of dental enamel is an important aspect in research on tooth decay. As an alternative to pH-electrodes our approach to the problem is the optical determination of pH by pH sensitive fluorescent dyes immobilized to tooth surfaces. In this study a model for measuring pH either on aminated cellulose substrates or on enamel (in vitro) with a fluorescein type dye is presented. The experimental realization is a fiber optic sensor with a nitrogen-pumped dye laser system and photodiode for the detection of the emitted fluorescence light. The surface pH values in the range between 4 and 7 were derived from the ratios of the excitation bands at 490 nm and 460 nm.

  20. Stability of some Cactaceae proteins based on fluorescence, circular dichroism, and differential scanning calorimetry measurements.

    Science.gov (United States)

    Gorinstein, S; Zemser, M; Vargas-Albores, F; Ochoa, J L; Paredes-Lopez, O; Scheler, C; Aksu, S; Salnikow, J

    1999-02-01

    Characterization of three cactus proteins (native and denatured) from Machaerocereus gummosus (Pitahaya agria), Lophocereu schottii (Garambullo), and Cholla opuntia (Cholla), was based on electrophoretic, fluorescence, CD (circular dichroism), DSC (differential scanning calorimetry), and FT-IR (Fourier transform infrared) measurements. The obtained results of intrinsic fluorescence, DSC, and CD were dissimilar for the three species of cactus, providing evidence of differences in secondary and tertiary structures. Cactus proteins may be situated in the following order corresponding to their relative stability: Machaerocereus gummosus (Pitahaya agria) > Cholla opuntia (Cholla) > Lophocereu schottii (Garambullo). Thermodynamic properties of proteins and their changes upon denaturation (temperature of denaturation, enthalphy, and the number of ruptured hydrogen bonds) were correlated with the secondary structure of proteins and disappearance of alpha-helix.

  1. Underwater Optical Fiber Fluorescent System for Measuring Chlorophyll-a Concentration

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Using optical fiber fluorescent technology,a new method for measuring alga concentration in water is presented. The system can realize on-line measurement for alga concentration using He-Ne laser as the light source. It can also effectively detect weak signals. The system with a passive sensor head has such advantages as simple structure, high sensitivity and high accuracy. It has been demonstrated that this system can be used to monitor water quality and can also be used to survey some matter.

  2. Biodegradability of anthropogenic organic matter in polluted rivers using fluorescence, UV, and BDOC measurements.

    Science.gov (United States)

    Knapik, Heloise G; Fernandes, Cristovão V S; de Azevedo, Julio Cesar R; dos Santos, Mauricius M; Dall'Agnol, Patrícia; Fontane, Darrell G

    2015-03-01

    The presence of highly urbanized and polluted areas affects both the quantity and the composition of organic matter in rivers through effluent loads and urban runoff discharges in watersheds. In such context, this paper aims to evaluate the biodegradability of anthropogenic organic matter in polluted rivers. Stream water samples were collected in three different sites considering a non-impacted area, a highly urbanized site located after a sewage treatment plant, and a site downstream of the watershed. For the biodegradation experiment, two adaptations of biodegradable dissolved organic carbon (BDOC) essay were evaluated to assess the decomposition rates between 10 days, with added nutrients, in the dark at 20 °C. The organic matter biodegradation was monitored by distinct parameters such as dissolved organic carbon (DOC), total organic carbon (TOC), particulate organic carbon (POC), fluorescence excitation-emission matrix (EEM), and UV absorbance measurements. The measured BDOC ranged from 0.8 mg/L at site IG01 (low anthropogenic occupation) to 4.2 mg/L at site IG02 (high impacted area), with averaged percentage of initial DOC ranging from 20 to 56 %, while an average of 28 % up to 95 % of POC can be considered as biodegradable. This pattern of biodegradation of fluorescent components was also observed through a decrease of tryptophan-like and tyrosine-like fluorescence peak intensity during the incubation time. The results also showed a higher decrease of humic-like fluorescence peak intensity at polluted sites (IG02 and IG05). Our experimental approach and monitoring strategy suggests that the evaluation of the organic matter biodegradability is essential to understand the fate and transformation mechanism of organic matter in urbanized and polluted rivers. And, considering a water quality planning and management perspective, this approach is important to identify the presence and location of organic compounds potentially important for dissolved oxygen

  3. In situ measurement of airway surface liquid [K+] using a ratioable K+-sensitive fluorescent dye.

    Science.gov (United States)

    Namkung, Wan; Song, Yuanlin; Mills, Aaron D; Padmawar, Prashant; Finkbeiner, Walter E; Verkman, A S

    2009-06-05

    The airway surface liquid (ASL) is the thin fluid layer lining airway surface epithelial cells, whose volume and composition are tightly regulated and may be abnormal in cystic fibrosis (CF). We synthesized a two-color fluorescent dextran to measure ASL [K(+)], TAC-Lime-dextran-TMR, consisting of a green-fluorescing triazacryptand K(+) ionophore-Bodipy conjugate, coupled to dextran, together with a red fluorescing tetramethylrhodamine reference chromophore. TAC-Lime-dextran-TMR fluorescence was K(+)-selective, increasing >4-fold with increasing [K(+)] from 0 to 40 mm. In well differentiated human airway epithelial cells, ASL [K(+)] was 20.8 +/- 0.3 mm and decreased by inhibition of the Na(+)/K(+) pump (ouabain), ENaC (amiloride), CF transmembrane conductance regulator (CFTR(inh)-172), or K(+) channels (TEA or XE991). ASL [K(+)] was increased by forskolin but not affected by Na(+)/K(+)/2Cl(-) cotransporter inhibition (bumetanide). Functional and expression studies indicated the involvement of [K(+)] channels KCNQ1, KCNQ3, and KCNQ5 as determinants of ASL [K(+)]. [K(+)] in CF cultures was similar to that in non-CF cultures, suggesting that abnormal ASL [K(+)] is not a factor in CF lung disease. In intact airways, ASL [K(+)] was also well above extracellular [K(+)]: 22 +/- 1 mm in pig trachea ex vivo and 16 +/- 1 mm in mouse trachea in vivo. Our results provide the first noninvasive measurements of [K(+)] in the ASL and indicate the involvement of apical and basolateral membrane ion transporters in maintaining a high ASL [K(+)].

  4. Study of calculated and measured time dependent delayed neutron yields. [TX, for calculating delayed neutron yields; MATINV, for matrix inversion; in FORTRAN for LSI-II minicomputer

    Energy Technology Data Exchange (ETDEWEB)

    Waldo, R.W.

    1980-05-01

    Time-dependent delayed neutron emission is of interest in reactor design, reactor dynamics, and nuclear physics studies. The delayed neutrons from neutron-induced fission of /sup 232/U, /sup 237/Np, /sup 238/Pu, /sup 241/Am, /sup 242m/Am, /sup 245/Cm, and /sup 249/Cf were studied for the first time. The delayed neutron emission from /sup 232/Th, /sup 233/U, /sup 235/U, /sup 238/U, /sup 239/Pu, /sup 241/Pu, and /sup 242/Pu were measured as well. The data were used to develop an empirical expression for the total delayed neutron yield. The expression gives accurate results for a large variety of nuclides from /sup 232/Th to /sup 252/Cf. The data measuring the decay of delayed neutrons with time were used to derive another empirical expression predicting the delayed neutron emission with time. It was found that nuclides with similar mass-to-charge ratios have similar decay patterns. Thus the relative decay pattern of one nuclide can be established by any measured nuclide with a similar mass-to-charge ratio. A simple fission product yield model was developed and applied to delayed neutron precursors. It accurately predicts observed yield and decay characteristics. In conclusion, it is possible to not only estimate the total delayed neutron yield for a given nuclide but the time-dependent nature of the delayed neutrons as well. Reactors utilizing recycled fuel or burning actinides are likely to have inventories of fissioning nuclides that have not been studied until now. The delayed neutrons from these nuclides can now be incorporated so that their influence on the stability and control of reactors can be delineated. 8 figures, 39 tables.

  5. Pyrene measurements in sooting low pressure methane flames by jet-cooled laser-induced fluorescence.

    Science.gov (United States)

    Wartel, M; Pauwels, J-F; Desgroux, P; Mercier, X

    2011-12-15

    This paper presents in detail the study we carried out concerning the pyrene measurement by jet-cooled laser-induced fluorescence (JCLIF) in different sooting low pressure methane flames. The aim of this paper is both to demonstrate the potentialities of this technique for the measurement of such moderately sized polycyclic aromatic hydrocarbons under sooting flame conditions and to provide new experimental data for the understanding and the development of chemical models of the soot formation processes. Several concentration profiles of pyrene measured in different sooting flame (various pressure and equivalence ratio) are presented. The validation of the JCLIF method for pyrene measurements is explained in detail as well as the calibration procedure, based on the standard addition method, which has been implemented for the quantification of the concentration profiles. Sensitivity lower than 1 ppb was obtained for the measurement of this species under sooting flame conditions.

  6. Upgrade of goniospectrophtometer GEFE for near-field scattering and fluorescence radiance measurements

    Science.gov (United States)

    Bernad, Berta; Ferrero, Alejandro; Pons, Alicia; Hernanz, M. L.; Campos, Joaquín.

    2015-03-01

    The goniospectrophotometer GEFE, designed and developed at IO-CSIC (Instituto de Optica, Agencia Estatal Consejo Superior de Investigaciones Cientificas), was conceived to measure the spectral Bidirectional Reflectance Distribution Function (BRDF) at any pair of irradiation and detection directions. Although the potential of this instrument has largely been proved, it still required to be upgraded to deal with some important scattering features for the assessment of the appearance. Since it was not provided with a detector with spatial resolution, it simply could not measure spectrophotometric quantities to characterize texture through the Bidirectional Texture Function (BTF) or translucency through the more complex Bidirectional Scattering-Surface Reflectance Distribution Function (BSSRDF). Another requirement in the GEFE upgrading was to provide it with the capability of measuring fluorescence at different geometries, since some of the new pigments used in industry are fluorescent, which can have a non-negligible impact in the color of the product. Then, spectral resolution at irradiation and detection had to be available in GEFE. This paper describes the upgrading of the goniospectrophotometer GEFE, and its new capabilities through the presentation of sparkle and goniofluorescence measurements. In addition, the potential of the instrument to evaluate translucency by the measurement of the BSSRDF is briefly discussed.

  7. High speed velocimetry and concentration measurements in a microfluidic mixer using fluorescence confocal microscopy

    Science.gov (United States)

    Inguva, Venkatesh; Perot, Blair; Kathuria, Sagar; Rothstein, Jonathan; Bilsel, Osman

    2016-11-01

    This work experimentally examines the performance of a quasi-turbulent micro-mixer that was designed to produce rapid mixing for protein-folding experiments. The original design of the mixer was performed using Direct Numerical Simulation (DNS) of the flow field and LES of the high Sc number scalar field representing the protein. The experimental work is designed to validate the DNS results. Both the velocity field and the protein concentration require validation. Different experiments were carried out to measure these two quantities. Concentration measurements are performed using a 488nm continuous wave laser coupled with a confocal microscope to measure fluorescence intensity during mixing. This is calibrated using the case where no mixing occurs. The velocity measurements use a novel high speed velocimetry technique capable of measuring speeds on the order of 10 m/s in a micro channel. The technique involves creating a pulsed confocal volume from a Ti-Sapphire laser with a pulse width of 260ns and observing the decay of fluorescence due to the fluid motion. Results from both experiments will be presented along with a comparison to the DNS results. The work is supported by NSF IDBR Award No. 1353942.

  8. Measurement of Yields and Fluctuations using Background and Calibration Data from the LUX Detector

    Science.gov (United States)

    Pease, Evan; LUX Collaboration

    2016-03-01

    The Large Underground Xenon (LUX) detector is a 350-kg liquid xenon (LXe) time-projection chamber designed for the direct detection of weakly-interacting massive particles (WIMPs), a leading dark matter candidate. LUX operates on the 4850-foot level of the Sanford Underground Research Facility in Lead, SD. Monoenergetic electronic recoil (ER) peaks in the WIMP search and calibration data from the first underground science run of the LUX detector have been used to measure ER light and charge yields in LXe between 5.2 keV and 662 keV. The energy resolution of the LUX detector at these energies will also be presented. Recombination fluctuations are observed to follow a linear dependence on the number of ions for the energies in this study, and this dependence is consistent with low-energy measurements made with a tritium beta source in the LUX detector. Using these results and additional measurements of the recoil bands from tritium and D-D neutron calibrations, I will compare recombination fluctuations in LXe response to electronic and nuclear recoils. The presenter is supported by the U.S. Department of Energy, Office of Science Graduate Student Research (SCGSR) program. The SCGSR program is administered by the Oak Ridge Institute for Science and Education for the DOE under contract DE-AC05-06OR23100.

  9. Shifts in the fluorescence lifetime of EGFP during bacterial phagocytosis measured by phase-sensitive flow cytometry

    Science.gov (United States)

    Li, Wenyan; Houston, Kevin D.; Houston, Jessica P.

    2017-01-01

    Phase-sensitive flow cytometry (PSFC) is a technique in which fluorescence excited state decay times are measured as fluorescently labeled cells rapidly transit a finely focused, frequency-modulated laser beam. With PSFC the fluorescence lifetime is taken as a cytometric parameter to differentiate intracellular events that are challenging to distinguish with standard flow cytometry. For example PSFC can report changes in protein conformation, expression, interactions, and movement, as well as differences in intracellular microenvironments. This contribution focuses on the latter case by taking PSFC measurements of macrophage cells when inoculated with enhanced green fluorescent protein (EGFP)-expressing E. coli. During progressive internalization of EGFP-E. coli, fluorescence lifetimes were acquired and compared to control groups. It was hypothesized that fluorescence lifetimes would correlate well with phagocytosis because phagosomes become acidified and the average fluorescence lifetime of EGFP is known to be affected by pH. We confirmed that average EGFP lifetimes consistently decreased (3 to 2 ns) with inoculation time. The broad significance of this work is the demonstration of how high-throughput fluorescence lifetime measurements correlate well to changes that are not easily tracked by intensity-only cytometry, which is affected by heterogeneous protein expression, cell-to-cell differences in phagosome formation, and number of bacterium engulfed.

  10. Estimation of Ce 4f-5d Interaction by Analysis of Partial Fluorescence Yield at the Ce L3 Edge of CeO2

    Science.gov (United States)

    Tonai, Hironori; Sasabe, Norimasa; Uozumi, Takayuki; Kawamura, Naomi; Mizumaki, Masaichiro

    2017-09-01

    Partial fluorescence yield (PFY) spectroscopy, which corresponds to a high-resolution version of the X-ray absorption spectroscopy (XAS), is experimentally performed at the Ce L3 edge of CeO2, and the result is theoretically analyzed using an impurity Anderson model (IAM). In order to estimate the Ce 4f-5d interaction Ufd, we employ a semi-empirical IAM framework based on the local density approximation+U method; Slater-Koster parameters describing the valence of CeO2 are estimated by band mapping within the linear combination of atomic orbitals scheme, and the resulting realistic valence structure is considered in the IAM analysis. The global structure of the PFY-XAS result, which consists of the Ce 2p3/2 → 5d dipole transition and the Ce 2p3/2 → 4f quadrupole transition, is excellently reproduced by the calculation. The Ufd value is estimated to be 3.0 eV. We emphasize that the sensitivity of PFY-XAS to Ufd makes it a good ruler for obtaining the Ufd values of Ce compounds.

  11. Measurement of mass yields from the 241Am(2nth,f reaction at the Lohengrin Spectrometer

    Directory of Open Access Journals (Sweden)

    Köster U.

    2013-03-01

    Full Text Available The study of fission yields has a major impact on the characterization and understanding of the fission process and is mandatory for reactor applications. While the yields are known for the major actinides (235U, 239Pu in the thermal neutron-induced fission, only few measurements have been performed on 242Am. The interest of 242Am concerns the reduction of radiotoxicity of 241Am in nuclear wastes using transmutation reactions. This paper presents the measurement of the fission mass yields from the reaction 241Am(2nth,f performed at the Lohengrin mass spectrometer (ILL, France for both the light and the heavy peaks: a total of 41 mass yields have been measured. The experiment was also meant to determine whether there is a difference in mass yields between the isomeric state and the ground state as it exists in fission and capture cross sections. The method used to address this question is based on a repeated measurement of a set of fission mass yields as a function of the ratio between the 242gAm and the 242mAm fission rates. The presented experiment is also a first step towards the measurement of the isotopic fission yields of 242Am.

  12. A novel fluorescence imaging approach for comparative measurements of pancreatic islet function in vitro.

    Science.gov (United States)

    Corbin, Kathryn L; Hall, Thomas E; Haile, Ruth; Nunemaker, Craig S

    2011-01-01

    Pancreatic islet dysfunction is a key element in the development of type 2 diabetes. Determining possible early warning signs of dysfunction is thus important to determining the underlying causes of diabetes. We describe an improved fluorescent imaging approach to detect potential islet dysfunction. Using Cell Tracker Red (CTR, a mildly thiol-reactive fluorescent probe) to positively label particular islets, we measured intracellular free calcium with fura-2 AM in both CTR-labeled and unlabeled sets of pancreatic islets simultaneously in vitro. This approach enhances sensitivity by controlling for differences in background fluorescence, temperature, and perifusion dynamics. We confirmed that 200 nM CTR produced no spectral overlap with fura-2 and no significant physiological effects in selective tests of islet function. To demonstrate the utility of dual-labeling, we compared untreated islets with islets pretreated with low-dose pro-inflammatory cytokines (IL-6 + IL-1B) to induce mild dysfunction. We alternated CTR-labeling between control and test islets and identified consistent reductions in the amplitude and trajectory of glucose-stimulated calcium responses (GSCa) among cytokine-treated islets that were independent of labeling. Observations were verified using a MATLAB program specifically designed to identify key features in the GSCa. Our findings thus demonstrate the utility of CTR-labeling in identifying islet dysfunction and propose that this technique can be adapted for other cells and tissues.

  13. A Practical Solution for 77 K Fluorescence Measurements Based on LED Excitation and CCD Array Detector.

    Directory of Open Access Journals (Sweden)

    Jacob Lamb

    Full Text Available The fluorescence emission spectrum of photosynthetic microorganisms at liquid nitrogen temperature (77 K provides important insights into the organization of the photosynthetic machinery of bacteria and eukaryotes, which cannot be observed at room temperature. Conventionally, to obtain such spectra, a large and costly table-top fluorometer is required. Recently portable, reliable, and largely maintenance-free instruments have become available that can be utilized to accomplish a wide variety of spectroscopy-based measurements in photosynthesis research. In this report, we show how to build such an instrument in order to record 77K fluorescence spectra. This instrument consists of a low power monochromatic light-emitting diode (LED, and a portable CCD array based spectrometer. The optical components are coupled together using a fiber optic cable, and a custom made housing that also supports a dewar flask. We demonstrate that this instrument facilitates the reliable determination of chlorophyll fluorescence emission spectra for the cyanobacterium Synechocystis sp. PCC 6803, and the green alga Chlamydomonas reinhardtii.

  14. Automatic measurement of compression wood cell attributes in fluorescence microscopy images.

    Science.gov (United States)

    Selig, B; Luengo Hendriks, C L; Bardage, S; Daniel, G; Borgefors, G

    2012-06-01

    This paper presents a new automated method for analyzing compression wood fibers in fluorescence microscopy. Abnormal wood known as compression wood is present in almost every softwood tree harvested. Compression wood fibers show a different cell wall morphology and chemistry compared to normal wood fibers, and their mechanical and physical characteristics are considered detrimental for both construction wood and pulp and paper purposes. Currently there is the need for improved methodologies for characterization of lignin distribution in wood cell walls, such as from compression wood fibers, that will allow for a better understanding of fiber mechanical properties. Traditionally, analysis of fluorescence microscopy images of fiber cross-sections has been done manually, which is time consuming and subjective. Here, we present an automatic method, using digital image analysis, that detects and delineates softwood fibers in fluorescence microscopy images, dividing them into cell lumen, normal and highly lignified areas. It also quantifies the different areas, as well as measures cell wall thickness. The method is evaluated by comparing the automatic with a manual delineation. While the boundaries between the various fiber wall regions are detected using the automatic method with precision similar to inter and intra expert variability, the position of the boundary between lumen and the cell wall has a systematic shift that can be corrected. Our method allows for transverse structural characterization of compression wood fibers, which may allow for improved understanding of the micro-mechanical modeling of wood and pulp fibers.

  15. Use of a laser-induced fluorescence thermal imaging system for film cooling heat transfer measurement

    Energy Technology Data Exchange (ETDEWEB)

    Chyu, M.K. [Carnegie Mellon Univ., Pittsburgh, PA (United States)

    1995-10-01

    This paper describes a novel approach based on fluorescence imaging of thermographic phosphor that enables the simultaneous determination of both local film effectiveness and local heat transfer on a film-cooled surface. The film cooling model demonstrated consists of a single row of three discrete holes on a flat plate. The transient temperature measurement relies on the temperature-sensitive fluorescent properties of europium-doped lanthanum oxysulfide (La{sub 2}O{sub 2}S:EU{sup 3+}) thermographic phosphor. A series of full-field surface temperatures, mainstream temperatures, and coolant film temperatures were acquired during the heating of a test surface. These temperatures are used to calculate the heat transfer coefficients and the film effectiveness simultaneously. Because of the superior spatial resolution capability for the heat transfer data reduced from these temperature frames, the laser-induced fluorescence (LIF) imaging system, the present study observes the detailed heat transfer characteristics over a film-protected surface. The trend of the results agrees with those obtained using other conventional thermal methods, as well as the liquid crystal imaging technique. One major advantage of this technique is the capability to record a large number of temperature frames over a given testing period. This offers multiple-sample consistency.

  16. A liquid parahydrogen target for the measurement of a parity-violating gamma asymmetry in n{sup {yields}+}p{yields}d+{gamma}

    Energy Technology Data Exchange (ETDEWEB)

    Santra, S., E-mail: s_satyaranjan@rediffmail.co [Indiana University Cyclotron Facility, 2401 Milo B. Sampson Lane, Bloomington, IN 47408 (United States); Barron Palos, L. [Arizona State University, Tempe, AZ 85287 (United States); Blessinger, C. [Indiana University Cyclotron Facility, 2401 Milo B. Sampson Lane, Bloomington, IN 47408 (United States); Bowman, J.D. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Chupp, T.E. [University of Michigan, Ann Arbor, MI 48104 (United States); Covrig, S. [Department of Physics, University of New Hampshire, Durham, NH 03824 (United States); Crawford, C. [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Dabaghyan, M. [Department of Physics, University of New Hampshire, Durham, NH 03824 (United States); Dadras, J. [Department of Physics, University of Tennessee, Knoxville, TN 37996 (United States); Dawkins, M.; Gericke, M.T.; Fox, W. [Indiana University Cyclotron Facility, 2401 Milo B. Sampson Lane, Bloomington, IN 47408 (United States); Gillis, R.C. [Department of Physics, University of Manitoba, Winnipeg, Manitoba, R3T2N2 (Canada); Leuschner, M.B.; Lozowski, B. [Indiana University Cyclotron Facility, 2401 Milo B. Sampson Lane, Bloomington, IN 47408 (United States); Mahurin, R. [Department of Physics, University of Tennessee, Knoxville, TN 37996 (United States); Mason, M. [Department of Physics, University of New Hampshire, Durham, NH 03824 (United States); Mei, J.; Nann, H. [Indiana University Cyclotron Facility, 2401 Milo B. Sampson Lane, Bloomington, IN 47408 (United States); Penttila, S.I. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2010-08-21

    A 16 l liquid parahydrogen target has been developed for a measurement of the parity-violating {gamma}-asymmetry in the capture of polarized cold neutrons on protons in the n{sup {yields}+}p{yields}d+{gamma} reaction by the NPDGamma collaboration. The target system was carefully designed to meet the stringent requirements on systematic effects for the experiment and also to satisfy hydrogen safety requirements. The target was designed to preserve the neutron polarization during neutron scattering on liquid hydrogen (LH{sub 2}), optimize the statistical sensitivity to the n{sup {yields}+}p{yields}d+{gamma} reaction, minimize backgrounds coming from neutron interaction with the beam windows of the target cryostat, minimize LH{sub 2} density fluctuations which can introduce extra noise in the gamma asymmetry signal, and control systematic effects. The target incorporates two mechanical refrigerators, two ortho-para convertors, an aluminum cryostat, an aluminum target vessel shielded with {sup 6}Li-rich plastic, a hydrogen fill/vent line with a passive recirculation loop to establish and maintain the equilibrium ortho-para ratio, a hydrogen relief system coupled to a vent stack, a gas handling system, and an alarm and interlock system. Low Z, nonmagnetic materials were used for the target vessel and cryostat. Pressure and temperature sensors monitored the thermodynamic state of the target. Relative neutron transmission measurements were used to monitor the parahydrogen fraction of the target. The target was thoroughly tested and successfully operated during the first phase of the NPDGamma experiment conducted at the FP12 beam line at Los Alamos Neutron Science Center (LANSCE). An upgraded version of the target system will be used in the next stage of the experiment, which will be performed at the Fundamental Neutron Physics Beam (FnPB) line of the Spallation Neutron Source at Oak Ridge National Laboratory.

  17. Z-scan fluorescence correlation spectroscopy as a tool for diffusion measurements in planar lipid membranes.

    Science.gov (United States)

    Steinberger, Tomáš; Macháň, Radek; Hof, Martin

    2014-01-01

    Studies of lateral diffusion are used for the characterization of the dynamics of biological membranes. One of the techniques that can be used for this purpose is fluorescence correlation spectroscopy (FCS), which belongs to the single-molecule techniques. Unfortunately, FCS measurements, when performed in planar lipid systems, are associated with a few sources of inaccuracy in the determination of the lateral diffusion coefficient. The main problems are related to the imperfect positioning of the laser focus relative to the plane of the sample. Another source of inaccuracy is the requirement for external calibration of the detection volume size. This protocol introduces a calibration-free method called Z-scan fluorescence correlation spectroscopy (Z-scan FCS), which is based on the determination of the diffusion time and particle number in steps along the optical (z-) axis by sequential FCS measurements. Z-scan FCS could be employed for diffusion measurements in planar membrane model systems-supported phospholipid bilayers (SPBs) and giant unilamellar vesicles (GUVs) and also in biological membranes. A result from measurements in SPBs is also presented in the protocol as a principle example of the Z-scan technique.

  18. Plant-Stress Measurements Using Laser-Induced Fluorescence Excitation: Poland Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Gene Capelle; Steve Jones

    1999-05-01

    Bechtel Nevada's Special Technologies Laboratory (STL) has been involved in remote sensing for many years, and in April 1995 STL began to study the use of active remote sensing for detecting plant stress. This work was motivated by the need to detect subsurface contamination, with the supposition that this could be accomplished by remote measurement of optical signatures from the overgrowing vegetation. The project has been a cooperative DOE/Disney effort, in which basic optical signature measurements (primarily fluorescence) were done at the Disney greenhouse facilities at Epcot Center in Florida, using instrumentation developed by STL on DOE funding. The primary instrument is a LIFI system, which had originally been developed for detection of surface uranium contamination at DOE sites. To deal specifically with the plant stress measurements, a LIFS system was built that utilizes the same laser, but captures the complete fluorescence spectrum from blue to red wavelengths. This system had continued to evolve, and the version in existence in September 1997 was sent to Poland, accompanied by two people from STL, for the purpose of making the measurements described in this report.

  19. Transmission Nuclear Resonance Fluorescence Measurements of 238U in Thick Targets

    Energy Technology Data Exchange (ETDEWEB)

    Quiter, Brian J.; Ludewigt, Bernhard A.; Mozin, Vladimir V.; Wilson, Cody; Korbly, Steve

    2010-08-31

    Transmission nuclear resonance fluorescence measurements were made on targets consisting of Pb and depleted U with total areal densities near 86 g/cm2. The 238U content n the targets varied from 0 to 8.5percent (atom fraction). The experiment demonstrates the capability of using transmission measurements as a non-destructive technique to identify and quantify the presence of an isotope in samples with thicknesses comparable to he average thickness of a nuclear fuel assembly. The experimental data also appear to demonstrate the process of notch refilling with a predictable intensity. Comparison of measured spectra to previous backscatter 238U measurements indicates general agreement in observed excited states. Two new 238U excited states and possibly a third state have also been observed.

  20. Measurement of buried undercut structures in microfluidic devices by laser fluorescent confocal microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Li Shiguang; Liu Jing; Nguyen, Nam-Trung; Fang Zhongping; Yoon, Soon Fatt

    2009-11-20

    Measuring buried, undercut microstructures is a challenging task in metrology. These structures are usually characterized by measuring their cross sections after physically cutting the samples. This method is destructive and the obtained information is incomplete. The distortion due to cutting also affects the measurement accuracy. In this paper, we first apply the laser fluorescent confocal microscopy and intensity differentiation algorithm to obtain the complete three-dimensional profile of the buried, undercut structures in microfluidic devices, which are made by the soft lithography technique and bonded by the oxygen plasma method. The impact of material wettability and the refractive index (n) mismatch among the liquid, samples, cover layer, and objective on the measurement accuracy are experimentally investigated.

  1. Measurement of Charged Pion Production Yields off the NuMI Target

    CERN Document Server

    Paley, J M; Raja, R; Akgun, U; Asner, D M; Aydin, G; Baker, W; Barnes,, P D; Bergfeld, T; Beverly, L; Bhatnagar, V; Choudhary, B; Dukes, E C; Duru, F; Feldman, G J; Godley, A; Graf, N; Gronberg, J; Gulmez, E; Gunaydin, Y O; Gustafson, H R; Hartouni, E P; Hanlet, P; Heffner, M; Kaplan, D M; Kamaev, O; Klay, J; Kumar, A; Lange, D J; Lebedev, A; Ling, J; Longo, M J; Lu, L C; Materniak, C; Mahajan, S; Meyer, H; Miller, D E; Mishra, S R; Nelson, K; Nigmanov, T; Norman, A; Onel, Y; Penzo, A; Peterson, R J; Rajaram, D; Ratnikov, D; Rosenfeld, C; Rubin, H; Seun, S; Singh, A; Solomey, N; Soltz, R A; Torun, Y; Wilson, K; Wright, D M; Wu, Q K

    2014-01-01

    The fixed-target MIPP experiment, Fermilab E907, was designed to measure the production of hadrons from the collisions of hadrons of momenta ranging from 5 to 120 GeV/c on a variety of nuclei. These data will generally improve the simulation of particle detectors and predictions of particle beam fluxes at accelerators. The spectrometer momentum resolution is between 3 and 4%, and particle identification is performed for particles ranging between 0.3 and 80 GeV/c using $dE/dx$, time-of-flight and Cherenkov radiation measurements. MIPP collected $1.42 \\times10^6$ events of 120 GeV Main Injector protons striking a target used in the NuMI facility at Fermilab. The data have been analyzed and we present here charged pion yields per proton-on-target determined in bins of longitudinal and transverse momentum between 0.5 and 80 GeV/c, with combined statistical and systematic relative uncertainties between 5 and 10%.

  2. Measurement of Charged Pion Production Yields off the NuMI Target

    Energy Technology Data Exchange (ETDEWEB)

    Paley, J. M.; et al.

    2014-08-04

    The fixed-target MIPP experiment, Fermilab E907, was designed to measure the production of hadrons from the collisions of hadrons of momenta ranging from 5 to 120 GeV/c on a variety of nuclei. These data will generally improve the simulation of particle detectors and predictions of particle beam fluxes at accelerators. The spectrometer momentum resolution is between 3 and 4%, and particle identification is performed for particles ranging between 0.3 and 80 GeV/c using $dE/dx$, time-of-flight and Cherenkov radiation measurements. MIPP collected $1.42 \\times10^6$ events of 120 GeV Main Injector protons striking a target used in the NuMI facility at Fermilab. The data have been analyzed and we present here charged pion yields per proton-on-target determined in bins of longitudinal and transverse momentum between 0.5 and 80 GeV/c, with combined statistical and systematic relative uncertainties between 5 and 10%.

  3. Measurement of pH micro-heterogeneity in natural cheese matrices by fluorescence lifetime imaging

    Directory of Open Access Journals (Sweden)

    Zuzana eBurdikova

    2015-03-01

    Full Text Available Cheese, a product of microbial fermentation may be defined as a protein matrix entrapping fat, moisture, minerals and solutes as well as dispersed bacterial colonies. The growth and physiology of bacterial cells in these colonies may be influenced by the microenvironment around the colony, or alternatively the cells within the colony may modify the microenvironment (e.g. pH, redox potential due to their metabolic activity. While cheese pH may be measured at macro level there remains a significant knowledge gap relating to the degree of micro-heterogeneity of pH within the cheese matrix and its relationship with microbial, enzymatic and physiochemical parameters and ultimately with cheese quality, consistency and ripening patterns. The pH of cheese samples was monitored both at macroscopic scale and at microscopic scale, using a non-destructive microscopic technique employing C-SNARF-4 and Oregon Green 488 fluorescent probes. The objectives of this work were to evaluate the suitability of these dyes for microscale pH measurements in natural cheese matrices and to enhance the sensitivity and extend the useful pH range of these probes using fluorescence lifetime imaging (FLIM. In particular, fluorescence lifetime of Oregon Green 488 proved to be sensitive probe to map pH micro heterogeneity within cheese matrices. Good agreement was observed between macroscopic scale pH measurement by FLIM and by traditional pH methods, but in addition considerable localized microheterogeneity in pH was evident within the curd matrix with pH range between 4.0 and 5.5. This technique provides significant potential to further investigate the relationship between cheese matrix physico-chemistry and bacterial metabolism during cheese manufacture and ripening.

  4. Particle velocity measurements with macroscopic fluorescence imaging in lymph tissue mimicking microfluidic phantoms

    Science.gov (United States)

    Hennessy, Ricky; Koo, Chiwan; Ton, Phuc; Han, Arum; Righetti, Raffaella; Maitland, Kristen C.

    2011-03-01

    Ultrasound poroelastography can quantify structural and mechanical properties of tissues such as stiffness, compressibility, and fluid flow rate. This novel ultrasound technique is being explored to detect tissue changes associated with lymphatic disease. We have constructed a macroscopic fluorescence imaging system to validate ultrasonic fluid flow measurements and to provide high resolution imaging of microfluidic phantoms. The optical imaging system is composed of a white light source, excitation and emission filters, and a camera with a zoom lens. The field of view can be adjusted from 100 mm x 75 mm to 10 mm x 7.5 mm. The microfluidic device is made of polydimethylsiloxane (PDMS) and has 9 channels, each 40 μm deep with widths ranging from 30 μm to 200 μm. A syringe pump was used to propel water containing 15 μm diameter fluorescent microspheres through the microchannels, with flow rates ranging from 0.5 μl/min to 10 μl/min. Video was captured at a rate of 25 frames/sec. The velocity of the microspheres in the microchannels was calculated using an algorithm that tracked the movement of the fluorescent microspheres. The imaging system was able to measure particle velocities ranging from 0.2 mm/sec to 10 mm/sec. The range of flow velocities of interest in lymph vessels is between 1 mm/sec to 10 mm/sec; therefore our imaging system is sufficient to measure particle velocity in phantoms modeling lymphatic flow.

  5. Measurement of pH micro-heterogeneity in natural cheese matrices by fluorescence lifetime imaging.

    Science.gov (United States)

    Burdikova, Zuzana; Svindrych, Zdenek; Pala, Jan; Hickey, Cian D; Wilkinson, Martin G; Panek, Jiri; Auty, Mark A E; Periasamy, Ammasi; Sheehan, Jeremiah J

    2015-01-01

    Cheese, a product of microbial fermentation may be defined as a protein matrix entrapping fat, moisture, minerals and solutes as well as dispersed bacterial colonies. The growth and physiology of bacterial cells in these colonies may be influenced by the microenvironment around the colony, or alternatively the cells within the colony may modify the microenvironment (e.g., pH, redox potential) due to their metabolic activity. While cheese pH may be measured at macro level there remains a significant knowledge gap relating to the degree of micro-heterogeneity of pH within the cheese matrix and its relationship with microbial, enzymatic and physiochemical parameters and ultimately with cheese quality, consistency and ripening patterns. The pH of cheese samples was monitored both at macroscopic scale and at microscopic scale, using a non-destructive microscopic technique employing C-SNARF-4 and Oregon Green 488 fluorescent probes. The objectives of this work were to evaluate the suitability of these dyes for microscale pH measurements in natural cheese matrices and to enhance the sensitivity and extend the useful pH range of these probes using fluorescence lifetime imaging (FLIM). In particular, fluorescence lifetime of Oregon Green 488 proved to be sensitive probe to map pH micro heterogeneity within cheese matrices. Good agreement was observed between macroscopic scale pH measurement by FLIM and by traditional pH methods, but in addition considerable localized microheterogeneity in pH was evident within the curd matrix with pH range between 4.0 and 5.5. This technique provides significant potential to further investigate the relationship between cheese matrix physico-chemistry and bacterial metabolism during cheese manufacture and ripening.

  6. Temperature measurements of micro-droplets using pulsed 2-color laser-induced fluorescence with MDR-enhanced energy transfer

    Science.gov (United States)

    Palmer, Johannes; Reddemann, Manuel A.; Kirsch, Valeri; Kneer, Reinhold

    2016-12-01

    In this work, a new measurement system is presented for studying temperature of micro-droplets by pulsed 2-color laser-induced fluorescence. Pulsed fluorescence excitation allows motion blur suppression and thus simultaneous measurements of droplet size, velocity and temperature. However, high excitation intensities of pulsed lasers lead to morphology-dependent resonances inside micro-droplets, which are accompanied by disruptive stimulated emission. Investigations showed that stimulated emission can be avoided by enhanced energy transfer via an additional dye. The suitability and accuracy of the new pulsed method are verified on the basis of a spectroscopic analysis and comparison to continuously excited 2-color laser-induced fluorescence.

  7. Recent Developments in Fluorescence Correlation Spectroscopy for Diffusion Measurements in Planar Lipid Membranes

    Directory of Open Access Journals (Sweden)

    Martin Hof

    2010-01-01

    Full Text Available Fluorescence correlation spectroscopy (FCS is a single molecule technique used mainly for determination of mobility and local concentration of molecules. This review describes the specific problems of FCS in planar systems and reviews the state of the art experimental approaches such as 2-focus, Z-scan or scanning FCS, which overcome most of the artefacts and limitations of standard FCS. We focus on diffusion measurements of lipids and proteins in planar lipid membranes and review the contributions of FCS to elucidating membrane dynamics and the factors influencing it, such as membrane composition, ionic strength, presence of membrane proteins or frictional coupling with solid support.

  8. CHANGES IN VALUES MEASURED WITH A LASER FLUORESCENCE SYSTEM FOR ENAMEL AND DENTIN ETHCED FOR DIFFERNT TIME INTERVALS - pilot study.

    OpenAIRE

    Radostina Anastasova; Mirela Marinova-Takorova; Vladimir E. Panov

    2014-01-01

    Purpose: The aim of the presented in vitro study was to evaluate the effectiveness of the laser fluorescent device DIAGNOdent in measuring changes in the level of mineralization of intact enamel surfaces etched for different time intervals and intact dentin etched for 30 sec. Material and methods: The study was performed on extracted human teeth. DIAGNOcam was used to measure the values of laser fluorescence of intact enamel and dentinal surfaces. Then the samples were treated with 37% H2...

  9. SU-C-303-05: Photosensitizer Determination for PDT Using Interstitial and Surface Measurements of Fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Kim, M; Finlay, J; Zhu, T [University of Pennsylvania, Philadelphia, PA (United States)

    2015-06-15

    Purpose: Photosensitizer concentration during photodynamic therapy (PDT) is an important parameter for accurate dosimetry. Fluorescence signal can be used as a measure of photosensitizer concentration. Two methods of data acquisition were compared to an ex vivo study both for in vivo and phantom models. Methods: Fluorescence signal of commonly used photosensitizer benzoporphyrin derivative monoacid ring A (BPD) was obtained in phantoms and mouse tumors using an excitation light of 405 nm. Interstitial fluorescence signal was obtained using a side-cut fiber inserted into the tumor tissue of interest. Using a previously developed multi-fiber probe, tumor surface fluorescence measurements were also collected. Signals were calibrated according to optical phantoms with known sensitizer fluorescence. Optical properties for each sample were determined and the influence of different absorption and scattering properties on the fluorescence signals was investigated. Using single value decomposition of the spectra, the sensitizer concentration was determined using the two different measurement geometries. An ex vivo analysis was also performed for tumor samples to determine the sensitizer concentration. Results: The two fluorescence signals obtained from the surface multi-fiber probe and the interstitial measurements were compared and were corresponding for both phantoms and mouse models. The values obtained were comparable to the ex vivo measurements as well. Despite the difference in geometry, the surface probe measurements can still be used as a metric for determining the presence of sensitizer in small volume tumors. Conclusion: The multi-fiber contact probe can be used as a tool to measure fluorescence at the surface of the treatment area for PDT and predict sensitizer concentration throughout the tumor. This is advantageous in that the measurement does not damage any tissue. Future work will include investigating the dependence of these results on intratumor sensitizer

  10. Development of a 2D temperature measurement technique for combustion diagnostics using 2-line atomic fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Engstroem, Johan

    2001-01-01

    The present thesis is concerned with the development and application of a novel planar laser-induced fluorescence (PLIF) technique for temperature measurements in a variety of combusting flows. Accurate measurement of temperature is an essential task in combustion diagnostics, since temperature is one of the most fundamental quantities for the characterization of combustion processes. The technique is based on two-line atomic fluorescence (TLAF) from small quantities of atomic indium (In) seeded into the fuel. It has been developed from small-scale experiments in laboratory flames to the point where practical combustion systems can be studied. The technique is conceptually simple and reveals temperature information in the post-flame regions. The viability of the technique has been tested in three extreme measurement situations: in spark ignition engine combustion, in ultra-lean combustion situations such as lean burning aero-engine concepts and, finally, in fuel-rich combustion. TLAF was successfully applied in an optical Sl engine using isooctane as fuel. The wide temperature sensitivity, 700 - 3000 K, of the technique using indium atoms allowed measurements over the entire combustion cycle in the engine to be performed. In applications in lean combustion a potential problem caused by the strong oxidation processes of indium atoms was encountered. This limits measurement times due to deposits of absorbing indium oxide on measurement windows. The seeding requirement is a disadvantage of the technique and can be a limitation in some applications. The results from experiments performed in sooting flames are very promising for thermometry measurements in such environments. Absorption by hydrocarbons and other native species was found to be negligible. Since low laser energies and low seeding concentrations could be used, the technique did not, unlike most other incoherent optical thermometry techniques, suffer interferences from LII of soot particles or LIF from PAH

  11. Improved sensitivity in flow cytometric intracellular ionized calcium measurement using fluo-3/Fura Red fluorescence ratios.

    Science.gov (United States)

    Novak, E J; Rabinovitch, P S

    1994-10-01

    Measurement of changes in intracellular ionized calcium concentrations ([Ca2+]i) has proved to be of wide use in the study of cellular responses to activating stimuli. The fluorescent dye Indo-1 has successfully been used in flow cytometry for this purpose, and when used as a ratiometric indicator it provides optimum sensitivity and accuracy. Unfortunately, this dye requires ultraviolet (UV) excitation which is often not available. We show here that similar results can be obtained using a ratio of green to red fluorescence from the simultaneous loading of the dyes Fura Red and fluo-3. Both Fura Red and fluo-3 are excited using the commonly available blue 488 nm laser line. With appropriate concentrations of the two dyes, the magnitude of response with the fluo-3/Fura Red ratio is greater than that achieved with indo-1, while the intercellular variation in measurement is similar to that seen with indo-1. Analyses can be simultaneously combined with immunofluorescent detection of PE-labeled antibodies to enable [Ca2+]i measurement within cell subsets.

  12. Image reconstruction for diagnosis and prognosis of breast cancer using fluorescence measurements: phantom studies

    Science.gov (United States)

    Roy, R.; Godavarty, A.; Thompson, A. B., Jr.; Sevick-Muraca, E. M.

    2005-04-01

    Fluorescence-enhance optical tomography is performed using (i) point illumination and point collection and (ii) area illumination and area collection geometrics in 3D. In both measurement techniques, an image-intensified charge-coupled (ICCD) imaging system is used in the frequency-domain to image near-infrared contrast agents. The experimental measurements are compared to diffusion model predictions in least squares form in the inverse problem. For image recovery for both area and point illumination geometries, an efficient gradient-based optimization technique based on the Penalty/modified barrier function (PMBF) method and the constrained truncated Newton with trust region (CONTN) method is developed. Targets in 3D were reconstructed from experimental data under two conditions of (i) perfect uptake (1:0, target to background ratio) and (ii) imperfect uptake (100:1, target to background ratio). Parameters of absorption cross section due to fluorophore and lifetimes are reconstructed. The present work demonstrates that 3D fluorescence enhanced optical tomography reconstructions can be successfully performed from both point/area illumination and collection experimental measurements of the time-dependent light propagation on clinically relevant tissue phantoms using a gain-modulated ICCD camera.

  13. Solvent sorting in (mixed solvent + electrolyte) systems: Time-resolved fluorescence measurements and theory

    Indian Academy of Sciences (India)

    Harun Al Rasidgazi; Hemant K Kashyap; Ranjit Biswas

    2015-01-01

    In this manuscriptwe explore electrolyte-induced modification of preferential solvation of a dipolar solute dissolved in a binary mixture of polar solvents. Composition dependence of solvation characteristics at a fixed electrolyte concentration has been followed. Binary mixtures of two different polarities have been employed to understand the competition between solute-ion and solute-solvent interactions. Time-resolved fluorescence Stokes shift and anisotropy have been measured for coumarin 153 (C153) in moderately polar (ethyl acetate + 1-propanol) and strongly polar (acetonitrile + propylene carbonate) binary mixtures at various mixture compositions, and in the corresponding 1.0M solutions of LiClO4. Both the mixtures show red shifts in C153 absorption and fluorescence emission upon increase of mole fraction of the less polar solvent component in presence of the electrolyte. In addition, measured average solvation times become slower and rotation times faster for the above change in the mixture composition. A semi-molecular theory based on solution density fluctuations has been developed and found to successfully capture the essential features of the measured Stokes shift dynamics of these complex multi-component mixtures. Dynamic anisotropy results have been analyzed by using both Stokes-Einstein-Debye (SED) and Dote-Kivelson-Schwartz (DKS) theories. The importance of local solvent structure around the dissolved solute has been stressed.

  14. Measuring the absolute deuterium-tritium neutron yield using the magnetic recoil spectrometer at OMEGA and the NIF.

    Science.gov (United States)

    Casey, D T; Frenje, J A; Gatu Johnson, M; Séguin, F H; Li, C K; Petrasso, R D; Glebov, V Yu; Katz, J; Knauer, J P; Meyerhofer, D D; Sangster, T C; Bionta, R M; Bleuel, D L; Döppner, T; Glenzer, S; Hartouni, E; Hatchett, S P; Le Pape, S; Ma, T; MacKinnon, A; McKernan, M A; Moran, M; Moses, E; Park, H-S; Ralph, J; Remington, B A; Smalyuk, V; Yeamans, C B; Kline, J; Kyrala, G; Chandler, G A; Leeper, R J; Ruiz, C L; Cooper, G W; Nelson, A J; Fletcher, K; Kilkenny, J; Farrell, M; Jasion, D; Paguio, R

    2012-10-01

    A magnetic recoil spectrometer (MRS) has been installed and extensively used on OMEGA and the National Ignition Facility (NIF) for measurements of the absolute neutron spectrum from inertial confinement fusion implosions. From the neutron spectrum measured with the MRS, many critical implosion parameters are determined including the primary DT neutron yield, the ion temperature, and the down-scattered neutron yield. As the MRS detection efficiency is determined from first principles, the absolute DT neutron yield is obtained without cross-calibration to other techniques. The MRS primary DT neutron measurements at OMEGA and the NIF are shown to be in excellent agreement with previously established yield diagnostics on OMEGA, and with the newly commissioned nuclear activation diagnostics on the NIF.

  15. Automated sorting of polymer flakes: fluorescence labeling and development of a measurement system prototype.

    Science.gov (United States)

    Brunner, S; Fomin, P; Kargel, Ch

    2015-04-01

    The extensive demand and use of plastics in modern life is associated with a significant economical impact and a serious ecological footprint. The production of plastics involves a high energy consumption and CO2 emission as well as the large need for (limited) fossil resources. Due to the high durability of plastics, large amounts of plastic garbage is mounting in overflowing landfills (plus 9.6 million tons in Europe in the year 2012) and plastic debris is floating in the world oceans or waste-to-energy combustion releases even more CO2 plus toxic substances (dioxins, heavy metals) to the atmosphere. The recycling of plastic products after their life cycle can obviously contribute a great deal to the reduction of the environmental and economical impacts. In order to produce high-quality recycling products, mono-fractional compositions of waste polymers are required. However, existing measurement technologies such as near infrared spectroscopy show limitations in the sorting of complex mixtures and different grades of polymers, especially when black plastics are involved. More recently invented technologies based on mid-infrared, Raman spectroscopy or laser-aided spectroscopy are still under development and expected to be rather expensive. A promising approach to put high sorting purities into practice is to label plastic resins with unique combinations of fluorescence markers (tracers). These are incorporated into virgin resins during the manufacturing process at the ppm (or sub ppm) concentration level, just large enough that the fluorescence emissions can be detected with sensitive instrumentation but neither affect the visual appearance nor the mechanical properties of the polymers. In this paper we present the prototype of a measurement and classification system that identifies polymer flakes (mill material of a few millimeters size) located on a conveyor belt in real time based on the emitted fluorescence of incorporated markers. Classification performance

  16. Excited-state dynamics of dGMP measured by steady-state and femtosecond fluorescence spectroscopy.

    Science.gov (United States)

    Miannay, Francois-Alexandre; Gustavsson, Thomas; Banyasz, Akos; Markovitsi, Dimitra

    2010-03-11

    The room-temperature fluorescence of 2'-deoxyguanosine 5'-monophosphate (dGMP) in aqueous solution is studied by steady-state and time-resolved fluorescence spectroscopy. The steady-state fluorescence spectrum of dGMP shows one band centered at 334 nm but has an extraordinary long red tail, extending beyond 700 nm. Both the fluorescence quantum yield and the relative weight of the 334 nm peak increase with the excitation wavelength. The initial fluorescence anisotropy after excitation at 267 nm is lower than 0.2 for all emission wavelengths, indicating an ultrafast S(2) --> S(1) internal conversion. The fluorescence decays depend strongly on the emission wavelength, getting longer with the wavelength. A rise time of 100-150 fs was observed for wavelengths longer than 450 nm, in accordance with a gradual red shift of the time-resolved spectra. The results are discussed in terms of a relaxation occurring mainly on the lowest excited (1)pi pi*-state surface toward a conical intersection with the ground state, in line with recent theoretical predictions. Our results show that the excited-state population undergoes a substantial "spreading out" before reaching the CI, explaining the complex dynamics observed.

  17. [Application of PARAFAC method and 3-D fluorescence spectra in petroleum pollutant measurement and analysis].

    Science.gov (United States)

    Pan, Zhao; Wang, Yu-tian; Shao, Xiao-qing; Wu, Xi-jun; Yang, Li-li

    2012-03-01

    A method for identification and concentration measurement of petroleum pollutant by combining three-dimensional (3-D) fluorescence spectra with parallel factor analysis (PARAFAC) was proposed. The main emphasis of research was the measurement of coexisting different kinds of petroleum. The CCl4 solutions of a 0# diesel sample, a 97# gasoline sample, and a kerosene sample were used as measurement objects. The condition of multiple petroleum coexistence was simulated by petroleum solutions with different mixed ratios. The character of PARAFAC in complex mixture coexisting system analysis was studied. The spectra of three kinds of solutions and the spectra of gasoline-diesel mixed samples, diesel-kerosene mixed samples, and gas oline-diesel mixed with small counts of kerosene interference samples were analyzed respectively. The core consistency diagnostic method and residual sum of squares method were applied to calculate the number of factors in PARAFAC. In gasoline-diesel experiment, gasoline or diesel can be identified and measured as a whole respectively by 2-factors parallel factors analysis. In diesel-kerosene experiment, 2-factors parallel factors analysis can only obtain the characters of diesel, and the 3rd factor is needed to separate the kerosene spectral character from the mixture spectrum. When small counts of kerosene exist in gasoline-diesel solution, gasoline and diesel still can be identified and measured as principal components by a 2-factors parallel factor analysis, and the effect of interference on qualitative analysis is not significant. The experiment verified that the PARAFAC method can obtain characteristic spectrum of each kind of petroleum, and the concentration of petroleum in solutions can be predicted simultaneously, with recoveries shown in the paper. The results showed the possibility of petroleum pollutant identification and concentration measurement based on the 3-D fluorescence spectra and PARAFAC.

  18. The 2010 Russian Drought Impact on Satellite Measurements of Solar-Induced Chlorophyll Fluorescence: Insights from Modeling and Comparisons with the Normalized Differential Vegetation Index (NDVI)

    Science.gov (United States)

    Yoshida, Y.; Joiner, J.; Tucker, C.; Berry, J.; Lee, J. -E.; Walker, G.; Reichle, R.; Koster, R.; Lyapustin, A.; Wang, Y.

    2015-01-01

    We examine satellite-based measurements of chlorophyll solar-induced fluorescence (SIF) over the region impacted by the Russian drought and heat wave of 2010. Like the popular Normalized Difference Vegetation Index (NDVI) that has been used for decades to measure photosynthetic capacity, SIF measurements are sensitive to the fraction of absorbed photosynthetically-active radiation (fPAR). However, in addition, SIF is sensitive to the fluorescence yield that is related to the photosynthetic yield. Both SIF and NDVI from satellite data show drought-related declines early in the growing season in 2010 as compared to other years between 2007 and 2013 for areas dominated by crops and grasslands. This suggests an early manifestation of the dry conditions on fPAR. We also simulated SIF using a global land surface model driven by observation-based meteorological fields. The model provides a reasonable simulation of the drought and heat impacts on SIF in terms of the timing and spatial extents of anomalies, but there are some differences between modeled and observed SIF. The model may potentially be improved through data assimilation or parameter estimation using satellite observations of SIF (as well as NDVI). The model simulations also offer the opportunity to examine separately the different components of the SIF signal and relationships with Gross Primary Productivity (GPP).

  19. Measurement of photoelectron yield of the CDEX-10 liquid argon detector prototype

    Science.gov (United States)

    Chen, Qing-Hao; Yue, Qian; Cheng, Jian-Ping; Kang, Ke-Jun; Li, Yuan-Jing; Lin, Shin-Ted; Tang, Chang-Jian; Xing, Hao-Yang; Yu, Xun-Zhen; Zeng, Ming; Zhu, Jing-Jun

    2016-11-01

    The China Dark Matter Experiment (CDEX) is a low background experiment at China Jinping Underground Laboratory (CJPL) designed to directly detect dark matter with a high-purity germanium (HPGe) detector. In the second phase, CDEX-10, which has a 10 kg germanium array detector system, a liquid argon (LAr) anti-Compton active shielding and cooling system is proposed. To study the properties of the LAr detector, a prototype with an active volume of 7 liters of liquid argon was built and operated. The photoelectron yields, as a critically important parameter for the prototype detector, have been measured to be 0.051-0.079 p.e./keV for 662 keV γ rays at different positions. The good agreement between the experimental and simulation results has provided a reasonable understanding and determination of the important parameters such as the surviving fraction of the excimers, the absorption length for 128 nm photons in liquid argon, the reflectivity of Teflon and so on.

  20. AN APPROACH TO THE MODEL USE FOR MEASURING SUSPENDED SEDIMENT YIELD IN UNGAUGED CATCHMENTS

    Directory of Open Access Journals (Sweden)

    Sokchhay Heng

    2013-01-01

    Full Text Available Different types of water resources studies require the information of Suspended Sediment Yield (SSY in different time resolutions. In ungauged watersheds where hydrometeorogical time series are not available, the mean annual SSY (SSYa is solely predictable and catchment area is traditionally used as the predictor because it is the most important variable and generally determined during project planning. Firstly, this research tried to advance the traditional SSYa model by additionally associating global topographic data. Based on the jack-knife procedure, the modified method considering catchment area with slope greater than 15% was evaluated in 17 gauged catchments in the Lower Mekong Basin and the overall predictive accuracy was improved about 66% in term of mean absolute percentage error. Secondly, the predicted SSYa in each modeled catchment was monthly distributed using Unit mean annual Sedimentograph (USGa. The double-average USGa superior to the single-average one provides overall better quality results than the regionalized USGa dependent upon the spatial proximity approach. The model performance measured by Nash-Sutcliffe Efficiency (NSE is about 0.66 in median value and satisfactory results (NSE >0.50 are obtained in 11 catchments. Lastly, the validated regional model was regarded as a potential and feasible tool in solving sediment-ungauged issues in the basin.

  1. Calculation of Apparent Activation Energy of Coal Oxidation at Low Temperatures by Measuring CO Yield

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    By analyzing previous studies on activation energy of coal oxidation at low temperatures, a theoretical calculation model of apparent activation energy is established. Yield of CO is measured by using the characteristic detector of coal oxidation at 30-90 ℃. The impact of parameters, such as airflow and particle size, on activation energies is analyzed. Finally, agreement was obtained between activation energies and the dynamic oxygen absorbed in order to test the accuracy of the model. The results show that: 1) a positive exponential relation between concentration of CO and temperature in the process of the experiment is obtained: increases are almost identical and the initial CO is low; 2) the apparent activation energies increase gradually with the sizes of particle at the same airflow, but the gradients increase at a decreasing rate; 3) the apparent activation energies increase linearly with airflow. For the five coal particles, the differences among the energies are relatively high when the airflow was low, but the differences were low when the airflow was high; 4) the optimum sizes of particle, 0.125-0.25 mm, and the optimum volume of airflow, 100 mL/min, are determined from the model; 5) the apparent activation energies decrease with an increase in oxygen absorbed. A negative exponential relation between the two is obtained.

  2. A chlorophyll fluorescence analysis of photosynthetic efficiency, quantum yield and photon energy dissipation in PSII antennae of Lactuca sativa L. leaves exposed to cinnamic acid.

    Science.gov (United States)

    Hussain, M Iftikhar; Reigosa, Manuel J

    2011-11-01

    This study investigated the effects of cinnamic acid (CA) on growth, biochemical and physiological responses of Lactuca sativa L. CA (0.1, 0.5, 1.0 and 1.5 mM) treatments decreased plant height, root length, leaf and root fresh weight, but it did not affect the leaf water status. CA treatment (1.5 mM) significantly reduced F(v), F(m), photochemical efficiency of PSII (F(v)/F(m)) and quantum yield of PSII (ΦPSII) photochemistry in L. sativa. The photochemical fluorescence quenching (qP) and non-photochemical quenching (NPQ) were reduced after treatment with 1.5 mM CA. Fraction of photon energy absorbed by PS II antennae trapped by "open" PS II reaction centers (P) was reduced by CA (1.5 mM) while, portion of absorbed photon energy thermally dissipated (D) and photon energy absorbed by PSII antennae and trapped by "closed" PSII reaction centers (E) was increased. Carbon isotope composition ratios (δ(13)C) was less negative (-27.10) in CA (1.5 mM) treated plants as compared to control (-27.61). Carbon isotope discrimination (Δ(13)C) and ratio of intercellular CO(2) concentration (ci/ca) from leaf to air were also less in CA treated plants. CA (1.5 mM) also decreased the leaf protein contents of L. sativa as compared to control.

  3. Annual laminae as measured using fluorescence in historic stalagmites from Baradla Cave, Aggtelek National Park, Hungary.

    Science.gov (United States)

    van Beynen, P.; Ford, D.; Schwarcz, H.

    2012-04-01

    capture delayed fluorescence. Experiments determined that there was negligible phosphorescence, that results were reproducible and were not affected by the grain of the film. Images were imported into IP-LAB Spectrum for data retrieval. They displayed strong couplet development with repeated layers of high-low fluorescence. Assuming that each couplet represents one climatic year, Sample AGG-1 was 165 years in age when collected; i.e. it commenced growing in 1827 CE. The true base of Sample AGG-2 was destroyed in extraction; it yielded an age of 156 years. Both are in excellent agreement with the expected ages. Correlation of fluorescence intensity and derived laminae thickness between the two samples is also excellent when fitted with a three-year running mean to avoid misallocation of individual years. Interannual fluorescence intensity grew slightly between ~1830 and 1900 CE, then was stable until minor decline commenced after 1970. Annual calcite lamina generally range between 0.5 and 1.0 mm in thickness in AGG-1 after 1900 CE, slightly less before that time. Thicknesses in AGG-2 follow the same trend but are consistently 0.1 -0.2 mm thinner. There is little correlation with the matching mean temperature and precipitation records from a nearby meteorological station that began operating in 1962. Relationships with much lengthier meteorological records from Miskolc and Budapest are being investigated.

  4. Airborne intercomparison of HOx measurements using laser-induced fluorescence and chemical ionization mass spectrometry during ARCTAS

    Directory of Open Access Journals (Sweden)

    J. H. Crawford

    2012-08-01

    Full Text Available The hydroxyl (OH and hydroperoxyl (HO2 radicals, collectively called HOx, play central roles in tropospheric chemistry. Accurate measurements of OH and HO2 are critical to examine our understanding of atmospheric chemistry. Intercomparisons of different techniques for detecting OH and HO2 are vital to evaluate their measurement capabilities. Three instruments that measured OH and/or HO2 radicals were deployed on the NASA DC-8 aircraft throughout Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS in the spring and summer of 2008. One instrument was the Penn State Airborne Tropospheric Hydrogen Oxides Sensor (ATHOS for OH and HO2 measurements based on Laser-Induced Fluorescence (LIF spectroscopy. A second instrument was the NCAR Selected-Ion Chemical Ionization Mass Spectrometer (SI-CIMS for OH measurement. A third instrument was the NCAR Peroxy Radical Chemical Ionization Mass Spectrometer (PeRCIMS for HO2 measurement. Formal intercomparison of LIF and CIMS was conducted for the first time on a same aircraft platform. The three instruments were calibrated by quantitative photolysis of water vapor by ultraviolet (UV light at 184.9 nm with three different calibration systems. The absolute accuracies were ±32% (2σ for the LIF instrument, ±65% (2σ for the SI-CIMS instrument, and ±50% (2σ for the PeRCIMS instrument. In general, good agreement was obtained between the CIMS and LIF measurements of both OH and HO2 measurements. Linear regression of the entire data set yields [OH]CIMS = 0.89 × [OH]LIF + 2.8 × 104 cm−3 with a correlation coefficient r2 = 0.72 for OH, and [HO2]CIMS = 0.86 × [HO2]LIF + 3.9 parts per trillion by volume (pptv, equivalent to pmol mol−1 with a correlation coefficient r2 = 0.72 for HO2. In general, the difference between CIMS and LIF instruments for OH and HO2 measurements can be explained by their combined measurement uncertainties. Comparison with box model results shows some

  5. In vitro quantitative light-induced fluorescence to measure changes in enamel mineralization.

    Science.gov (United States)

    Gmür, Rudolf; Giertsen, Elin; van der Veen, Monique H; de Josselin de Jong, Elbert; ten Cate, Jacob M; Guggenheim, Bernhard

    2006-09-01

    A sensitive, quantitative method for investigating changes in enamel mineralization of specimens subjected to in vitro or in situ experimentation is presented. The fluorescence-detecting instrument integrates a Xenon arc light source and an object positioning stage, which makes it particularly suitable for the nondestructive assessment of demineralized or remineralized enamel. We demonstrate the ability of in vitro quantitative light-induced fluorescence (QLF) to quantify changes in mineralization of bovine enamel discs that had been exposed in vitro to a demineralizing gel (n=36) or biofilm-mediated demineralization challenges (n=10), or were carried in situ by three volunteers during a 10-day experiment (n=12). Further experiments show the technique's value for monitoring the extent of remineralization in 36 specimens exposed in vitro to oral multispecies biofilms and document the repeatability of in vitro QLF measurements (n=10) under standardized assay conditions. The validity of the method is illustrated by comparison with transversal microradiography (TMR), the invasive current gold standard for assessing experimental changes in enamel mineralization. Ten discs with 22 measurement areas for comparison demonstrated a positive correlation between TMR and QLF (r=0.82). Filling a technological gap, this QLF system is a promising tool to assay in vitro nondestructively localized changes in mineralization of enamel specimens.

  6. Guided fluorescence diagnosis of childhood caries: preliminary measures correlate with depth of carious decay

    Science.gov (United States)

    Timoshchuk, Mari-Alina; Zhang, Liang; Dickinson, Brian A.; Ridge, Jeremy S.; Kim, Amy S.; Baltuck, Camille T.; Nelson, Leonard Y.; Berg, Joel H.; Seibel, Eric J.

    2014-02-01

    The current rise in childhood caries worldwide has increased the demand for portable technologies that can quickly and accurately detect and diagnose early stage carious lesions. These lesions, if identified at an early stage, can be reversed with remineralization treatments, education, and improvements in home care. A multi-modal optical prototype for detecting and diagnosing occlusal caries demineralization in vivo has been developed and pilot tested. The device uses a 405-nm laser as a scanned illumination source to obtain high resolution and high surface contrast reflectance images, which allows the user to quickly image and screen for any signs of demineralized enamel. When a suspicious region is located, the device can be switched to perform dual laser fluorescence spectroscopy using 405-nm and 532-nm laser excitations. These spectra are used to compute an auto-fluorescence (AF) ratio of the suspicious region and the percent difference of AF ratios from a healthy region of the same tooth. The device was tested on 7 children's teeth in vivo with clinically diagnosed carious lesions. Lesion depth was then visually estimated from the video image using the 405-nm scanned light source, and within a month the maximum drill depth was assessed by a clinician. The researcher and clinicians were masked from previous measurements in a blinded study protocol. Preliminary results show that the ratiometric percent difference measurement of the AF spectrum of the tooth correlates with the severity of the demineralization as assessed by the clinician after drilling.

  7. Three-dimensional printed miniaturized spectral system for collagen fluorescence lifetime measurements

    Science.gov (United States)

    Zou, Luwei; Koslakiewicz, Ronald; Mahmoud, Mohamad; Fahs, Mehdi; Liu, Rui; Lo, Joe Fujiou

    2016-07-01

    Various types of collagens, e.g., type I and III, represent the main load-bearing components in biological tissues. Their composition changes during processes such as wound healing and fibrosis. When excited by ultraviolet light, collagens exhibit autofluorescence distinguishable by their unique fluorescent lifetimes across a range of emission wavelengths. Here, we designed a miniaturized spectral-lifetime detection system as a noninvasive probe for monitoring tissue collagen compositions. A sine-modulated LED illumination was applied to enable frequency domain fluorescence lifetime measurements under three wavelength bands, separated via a series of longpass dichroics at 387, 409, and 435 nm. We employed a lithography-based three-dimensional (3-D) printer with modeling to simulate the effect of thermal (from LED) and mechanical (from handling) strain on the optical system. The geometry was further optimized with ray tracing to form the final 3-D printed structure. Using this device, the phase shift and demodulation of collagen types were measured, where the separate spectral bands enhanced the differentiation of their lifetimes. This system represents a low cost, handheld probe for clinical tissue monitoring applications.

  8. Measurement of fission yields from the 241Am(2nth,f reaction at the Lohengrin Spectrometer

    Directory of Open Access Journals (Sweden)

    Amouroux Ch.

    2013-12-01

    Full Text Available The study of fission yields has a major impact on the characterization and understanding of the fission process and is mandatory for reactor applications. While the yields are known for the major actinides (235U, 239Pu in the thermal neutron-induced fission, only few measurements have been performed on 242Am. This paper presents the results of a measurement at the Lohengrin mass spectrometer (ILL, France on the reaction 241Am(2nth,f: a total of 41 mass yields in the light and the heavy peaks have been measured and compared with the fission process simulation code GEF. Modus operandi and first results of a second experiment performed in May 2013 on the same reaction but with the goal of extracting the isotopic yields are presented as well: 8 mass yields were re-measured and 18 isotopic yields have been investigated and are being analyzed. Results concerning the kinetic energy and its comparison with the GEF Code are also presented in this paper.

  9. Measurements of Sub-Barrier Transfer Yields in SULFUR-32 + NIOBIUM-93, MOLYBDENUM(98,100) Reactions at 180 Degrees

    Science.gov (United States)

    Roberts, Roland Blaine

    1994-01-01

    The Rochester RMS was used to measure excitation functions for 180^circ sub -barrier one- and two-neutron pickup reactions for E _{rm lab} final states were not identified. The RMS technique was chosen for its self-normalizing property which makes obtaining absolute cross sections straightforward. The distorted-wave Born-approximation (DWBA) computer code scPTOLEMY was used to obtain quantal predictions of the one-neutron pickup yields. The calculations were performed for several final states and summed (using the appropriate spectroscopic factors) to estimate the total quasi-elastic transfer yield. P scTOLEMY over-predicted the yield in each system by a factor of 2-3. Since DWBA calculations for heavy-ion reactions are known to have difficulty reproducing experimentally measured yields within a factor of two, this discrepancy is not surprising. Although the absolute yields were not reproduced by the calculations, the shape of the excitation function is well reproduced. No calculations were performed for two-neutron transfer due to the lack of reliable spectroscopic factors. The transfer probabilities are obtained directly from these measurements. Distances of closest approach were calculated using a proximity potential. The slopes of transfer probability vs distance of closest approach are in good agreement with the predictions obtained from semi-classical theory using binding energies, indicating the absence of a "slope anomaly." This is consistent with the prediction that diffractive effects, which may distort the measured slope, are minimized at backward angles and sub-barrier energies--the precise conditions under which these measurements were performed. Angle-integrated transfer cross sections were derived from the measured transfer probabilities by assuming the ions follow Rutherford trajectories. These derived yields are consistent with the hypothesis that fusion enhancements in previously measured fusion yields for the ^ {32}S + ^{98,100} Mo systems are

  10. Saturated fluorescence measurements of the hydroxyl radical in laminar high-pressure flames

    Science.gov (United States)

    Carter, Campbell D.; King, Galen B.; Laurendeau, Normand M.

    1990-01-01

    The efficacy of laser saturated fluorescence (LSF) for OH concentration measurements in high pressure flames was studied theoretically and experimentally. Using a numerical model describing the interaction of hydroxyl with nonuniform laser excitation, the effect of pressure on the validity of the balanced cross-rate model was studied along with the sensitivity of the depopulation of the laser-coupled levels to the ratio of rate coefficients describing: (1) electronic quenching to (sup 2) Sigma (+) (v double prime greater than 0), and (2) vibrational relaxation from v double prime greater than 0 to v double prime = 0. At sufficiently high pressures and near-saturated conditions, the total population of the laser-coupled levels reaches an asymptotic value, which is insensitive to the degree of saturation. When the ratio of electronic quenching to vibrational relaxation is small and the rate of coefficients for rotational transfer in the ground and excited electronic states are nearly the same, the balanced cross-rate model remains a good approximation for all pressures. When the above ratio is large, depopulation of the laser-coupled levels becomes significant at high pressures, and thus the balanced cross-rate model no longer holds. Under these conditions, however, knowledge of the depletion of the laser-coupled levels can be used to correct the model. A combustion facility for operation up to 20 atm was developed to allow LSF measurements of OH in high pressure flames. Using this facility, partial saturation in laminar high pressure (less than or equal to 12.3 atm) C2H6/O2/N2 flames was achieved. To evaluate the limits of the balanced cross-rate model, absorption and calibrated LSF measurements at 3.1 and 6.1 atm were compared. The fluorescence voltages were calibrated with absorption measurements in an atmospheric flame and corrected for their finite sensitivity to quenching with: (1) estimated quenching rate coefficients, and (2) an in situ measurement from a

  11. Intercomparison of Hantzsch and fiber-laser-induced-fluorescence formaldehyde measurements

    Science.gov (United States)

    Kaiser, J.; Li, X.; Tillmann, R.; Acir, I.; Holland, F.; Rohrer, F.; Wegener, R.; Keutsch, F. N.

    2014-06-01

    Two gas-phase formaldehyde (HCHO) measurement techniques, a modified commercial wet-chemical instrument based on Hantzsch fluorimetry and a custom-built instrument based on fiber laser-induced fluorescence (FILIF), were deployed at the atmospheric simulation chamber SAPHIR (Simulation of Atmospheric PHotochemistry In a large Reaction Chamber) to compare the instruments' performances under a range of conditions. Thermolysis of para-HCHO and ozonolysis of 1-butene were used as HCHO sources, allowing for calculations of theoretical HCHO mixing ratios. Calculated HCHO mixing ratios are compared to measurements, and the two measurements are also compared. Experiments were repeated under dry and humid conditions (RH 60%) to investigate the possibility of a water artifact in the FILIF measurements. The ozonolysis of 1-butene also allowed for the investigation of an ozone artifact seen in some Hantzsch measurements in previous intercomparisons. Results show that under all conditions the two techniques are well correlated (R2 ≥ 0.997), and linear regression statistics show measurements agree with within stated uncertainty (15% FILIF + 5% Hantzsch). No water or ozone artifacts are identified. While a slight curvature is observed in some Hantzsch vs. FILIF regressions, the potential for variable instrument sensitivity cannot be attributed to a single instrument at this time. Measurements at low concentrations highlight the need for a secondary method for testing the purity of air used in instrument zeroing and the need for further FILIF White cell outgassing experiments.

  12. Experimental phase diagram of negatively supercoiled DNA measured by magnetic tweezers and fluorescence

    Science.gov (United States)

    Vlijm, Rifka; Mashaghi, Alireza; Bernard, Stéphanie; Modesti, Mauro; Dekker, Cees

    2015-02-01

    The most common form of DNA is the well-known B-structure of double-helix DNA. Many processes in the cell, however, exert force and torque, inducing structural changes to the DNA that are vital to biological function. Virtually all DNA in cells is in a state of negative supercoiling, with a DNA structure that is complex. Using magnetic tweezers combined with fluorescence imaging, we here study DNA structure as a function of negative supercoiling at the single-molecule level. We classify DNA phases based on DNA length as a function of supercoiling, down to a very high negative supercoiling density σ of -2.5, and forces up to 4.5 pN. We characterize plectonemes using fluorescence imaging. DNA bubbles are visualized by the binding of fluorescently labelled RPA, a eukaryotic single-strand-binding protein. The presence of Z-DNA, a left-handed form of DNA, is probed by the binding of Zα77, the minimal binding domain of a Z-DNA-binding protein. Without supercoiling, DNA is in the relaxed B-form. Upon going toward negative supercoiling, plectonemic B-DNA is being formed below 0.6 pN. At higher forces and supercoiling densities down to about -1.9, a mixed state occurs with plectonemes, multiple bubbles and left-handed L-DNA. Around σ = -1.9, a buckling transition occurs after which the DNA end-to-end length linearly decreases when applying more negative turns, into a state that we interpret as plectonemic L-DNA. By measuring DNA length, Zα77 binding, plectoneme and ssDNA visualisation, we thus have mapped the co-existence of many DNA structures and experimentally determined the DNA phase diagram at (extreme) negative supercoiling.The most common form of DNA is the well-known B-structure of double-helix DNA. Many processes in the cell, however, exert force and torque, inducing structural changes to the DNA that are vital to biological function. Virtually all DNA in cells is in a state of negative supercoiling, with a DNA structure that is complex. Using magnetic tweezers

  13. Latent manganese deficiency in barley can be diagnosed and remediated on the basis of chlorophyll a fluorescence measurements

    DEFF Research Database (Denmark)

    Schmidt, Sidsel Birkelund; Pedas, Pai; Laursen, Kristian Holst;

    2013-01-01

    chlorophyll (Chl) a fluorescence as a tool for diagnosis of latent Mn deficiency. Methods: Barley plants grown under controlled greenhouse conditions or in the field were exposed to different intensities of Mn deficiency. The responses were characterised by analysis of Chl a fluorescence, photosystem II (PSII......) proteins and mineral elements. Results: Analysis of the Chl a fluorescence induction kinetics (FIK) revealed distinct changes long before any visual symptoms of Mn deficiency were apparent. The changes were specific for Mn and did not occur in Mg, S, Fe or Cu deficient plants. The changes in Mn deficient......Background and aims: Manganese (Mn) deficiency represents a major plant nutritional disorder in winter cereals. The deficiency frequently occurs latently and the lack of visual symptoms prevents timely remediation and cause significant yield reductions. These problems prompted us to investigate...

  14. Measurement of mercury bound in the glass envelope during operation of fluorescent lamps

    Energy Technology Data Exchange (ETDEWEB)

    Thaler, E.G.; Wilson, R.H.; Doughty, D.A.; Beers, W.W. [GE Corporate Research and Development, Schenectady, NY (United States)

    1995-06-01

    Mercury vapor is essential to the high efficiency conversion of electrical power to light in fluorescent lamps. However, the amount of mercury that must be added to the lamp to achieve a 20,000 h operating life is much larger than the amount of vapor needed for the discharge. This is a result of processes that bind the mercury during lamp operation and make it unavailable as mercury vapor. As part of an effort to determine the amount of mercury that must be added to standard GE F40T12 lamps with halophosphate phosphors the authors have measured the mercury bound in the soda-lime glass under the phosphor in the positive column in a series of these lamps. From these measurements they have developed an empirical model which describes the amount of mercury per unit area that is bound in the glass as a function of operating time and the weight of phosphor over the glass.

  15. High resolution isotope shifts and hyperfine structure measurements of tungsten by laser induced fluorescence spectroscopy

    CERN Document Server

    Lee, Jeongwon; Leanhardt, Aaron

    2012-01-01

    Isotope shifts and hyperfine structure of tungsten were studied in the near UV range. We have used laser induced fluorescence spectroscopy on a pulsed supersonic beam to probe the 5D0 -> 5F1 transition at 384.9 nm, 7S3 -> 7P4 transition at 400.9 nm, and 7S3 -> 7P3 transition at 407.4 nm. Three new magnetic hyperfine constants are reported for 7P3,7P4, and 5F1 states. The isotope shifts of the 384.9 nm transition are presented for the first time, and the isotope shifts of 400.9 nm and 407.4 nm transition are measured with an order of magnitude higher precision compared to the previous measurements. As a result, the nuclear parameters lambda and lambda_{rel} are extracted from the isotope shifts with an improved precision.

  16. Chromosome translocations measured by fluorescence in-situ hybridization: A promising biomarker

    Energy Technology Data Exchange (ETDEWEB)

    Lucas, J.N.; Straume, T.

    1995-10-01

    A biomarker for exposure and risk assessment would be most useful if it employs an endpoint that is highly quantitative, is stable with time, and is relevant to human risk. Recent advances in chromosome staining using fluorescence in situ hybridization (FISH) facilitate fast and reliable measurement of reciprocal translocations, a kind of DNA damage linked to both prior exposure and risk. In contrast to other biomarkers available, the frequency of reciprocal translocations in individuals exposed to whole-body radiation is stable with time post exposure, has a rather small inter-individual variability, and can be measured accurately at the low levels. Here, the authors discuss results from their studies demonstrating that chromosome painting can be used to reconstruct radiation dose for workers exposed within the dose limits, for individuals exposed a long time ago, and even for those who have been diagnosed with leukemia but not yet undergone therapy.

  17. Lymphocyte fluorescence polarization measurements with the cellscan system: application to the SCM cancer test.

    Science.gov (United States)

    Deutsch, M; Ron, I; Weinreb, A; Tirosh, R; Chaitchik, S

    1996-02-01

    The SCM (Structuredness of Cytoplasmic Matrix) cancer test, a procedure based on detection of differences in lymphocyte activation between individuals with and without cancer, has remained controversial with inconsistent results reported by different authors. As originally described, the test includes two technically demanding steps, the first a lymphocyte separation procedure and the second a series of fluorescence polarization measurements. The Cellscan, a high-precision static cytometer system has been configured to perform the SCM test. The apparatus facilitates the polarization measurements and can analyze cells separated using simpler procedures than were originally described. Using methods and diagnostic criteria adapted for the Cellscan system, the SCM test correctly classified > 90% of patients with cancer and > 90% of individuals without cancer.

  18. Spectral fluorescence signature techniques and absorption measurements for continuous monitoring of biofuel-producing microalgae cultures

    Science.gov (United States)

    Martín de la Cruz, M. C.; Gonzalez Vilas, L.; Yarovenko, N.; Spyrakos, E.; Torres Palenzuela, J. M.

    2013-08-01

    Biofuel production from microalgae can be both sustainable and economically viable. Particularly in the case of algal growth in wastewater an extra benefit is the removal or biotransformation of pollutants from these types of waters. A continuous monitoring system of the microalgae status and the concentration of different wastewater contaminants could be of great help in the biomass production and the water characterisation. In this study we present a system where spectral fluorescence signature (SFS) techniques are used along with absorption measurements to monitor microalgae cultures in wastewater and other mediums. This system aims to optimise the microalgae production for biofuel applications or other uses and was developed and tested in prototype indoor photo-bioreactors at the University of Vigo. SFS techniques were applied using the fluorescence analyser INSTAND-SCREENER developed by Laser Diagnostic Instruments AS. INSTAND-SCREENER permits wavelength scanning in two modes, one in UV and another in VIS. In parallel, it permits the on-line monitoring and rapid analysis of both water quality and phytoplankton status without prior treatment of the sample. Considering that different contaminants and microalgae features (density, status etc.) have different spectral signatures of fluorescence and absorption properties, it is possible to characterise them developing classification libraries. Several algorithms were used for the classification. The implementation of this system in an outdoor raceway reactor in a Spanish wastewater treatment plant is also discussed. This study was part of the Project EnerBioAlgae (http://www.enerbioalgae.com/), which was funded by the Interreg SUDOE and led by the University of Vigo.

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

    Science.gov (United States)

    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.

  20. Experimental phase diagram of negatively supercoiled DNA measured by magnetic tweezers and fluorescence.

    Science.gov (United States)

    Vlijm, Rifka; Mashaghi, Alireza; Bernard, Stéphanie; Modesti, Mauro; Dekker, Cees

    2015-02-21

    The most common form of DNA is the well-known B-structure of double-helix DNA. Many processes in the cell, however, exert force and torque, inducing structural changes to the DNA that are vital to biological function. Virtually all DNA in cells is in a state of negative supercoiling, with a DNA structure that is complex. Using magnetic tweezers combined with fluorescence imaging, we here study DNA structure as a function of negative supercoiling at the single-molecule level. We classify DNA phases based on DNA length as a function of supercoiling, down to a very high negative supercoiling density σ of -2.5, and forces up to 4.5 pN. We characterize plectonemes using fluorescence imaging. DNA bubbles are visualized by the binding of fluorescently labelled RPA, a eukaryotic single-strand-binding protein. The presence of Z-DNA, a left-handed form of DNA, is probed by the binding of Zα77, the minimal binding domain of a Z-DNA-binding protein. Without supercoiling, DNA is in the relaxed B-form. Upon going toward negative supercoiling, plectonemic B-DNA is being formed below 0.6 pN. At higher forces and supercoiling densities down to about -1.9, a mixed state occurs with plectonemes, multiple bubbles and left-handed L-DNA. Around σ = -1.9, a buckling transition occurs after which the DNA end-to-end length linearly decreases when applying more negative turns, into a state that we interpret as plectonemic L-DNA. By measuring DNA length, Zα77 binding, plectoneme and ssDNA visualisation, we thus have mapped the co-existence of many DNA structures and experimentally determined the DNA phase diagram at (extreme) negative supercoiling.

  1. Real time measures of prestin charge and fluorescence during plasma membrane trafficking reveal sub-tetrameric activity.

    Directory of Open Access Journals (Sweden)

    Shumin Bian

    Full Text Available Prestin (SLC26a5 is the outer hair cell integral membrane motor protein that drives cochlear amplification, and has been described as an obligate tetramer. We studied in real time the delivery of YFP-prestin to the plasma membrane of cells from a tetracycline-inducible cell line. Following the release of temperature block to reinstate trans Golgi network delivery of the integral membrane protein, we measured nonlinear capacitance (NLC and membrane fluorescence during voltage clamp. Prestin was delivered exponentially to the plasma membrane with a time constant of less than 10 minutes, with both electrical and fluorescence methods showing high temporal correlation. However, based on disparity between estimates of prestin density derived from either fluorescence or NLC, we conclude that sub-tetrameric forms of prestin contribute to our electrical and fluorescence measures. Thus, in agreement with previous observations we find that functional prestin is not an obligate tetramer.

  2. Measurement of OH reactivity by laser flash photolysis coupled with laser-induced fluorescence spectroscopy

    Science.gov (United States)

    Stone, Daniel; Whalley, Lisa K.; Ingham, Trevor; Edwards, Peter M.; Cryer, Danny R.; Brumby, Charlotte A.; Seakins, Paul W.; Heard, Dwayne E.

    2016-07-01

    OH reactivity (k'OH) is the total pseudo-first-order loss rate coefficient describing the removal of OH radicals to all sinks in the atmosphere, and is the inverse of the chemical lifetime of OH. Measurements of ambient OH reactivity can be used to discover the extent to which measured OH sinks contribute to the total OH loss rate. Thus, OH reactivity measurements enable determination of the comprehensiveness of measurements used in models to predict air quality and ozone production, and, in conjunction with measurements of OH radical concentrations, to assess our understanding of OH production rates. In this work, we describe the design and characterisation of an instrument to measure OH reactivity using laser flash photolysis coupled to laser-induced fluorescence (LFP-LIF) spectroscopy. The LFP-LIF technique produces OH radicals in isolation, and thus minimises potential interferences in OH reactivity measurements owing to the reaction of HO2 with NO which can occur if HO2 is co-produced with OH in the instrument. Capabilities of the instrument for ambient OH reactivity measurements are illustrated by data collected during field campaigns in London, UK, and York, UK. The instrumental limit of detection for k'OH was determined to be 1.0 s-1 for the campaign in London and 0.4 s-1 for the campaign in York. The precision, determined by laboratory experiment, is typically < 1 s-1 for most ambient measurements of OH reactivity. Total uncertainty in ambient measurements of OH reactivity is ˜ 6 %. We also present the coupling and characterisation of the LFP-LIF instrument to an atmospheric chamber for measurements of OH reactivity during simulated experiments, and provide suggestions for future improvements to OH reactivity LFP-LIF instruments.

  3. Measurement of radical-species concentrations and polycyclic aromatic hydrocarbons in flames by fluorescence and absorption using a tunable dye laser. Progress report, March 1, 1980-February 28, 1981

    Energy Technology Data Exchange (ETDEWEB)

    Lucht, R.P.; Sweeney, D.W.; Laurendeau, N.M.

    1981-03-01

    A theoretical and experimental investigation of OH saturated fluorescence is described. The goal of the research is to develop a saturated fluorescence technique which will yield accurate molecular number densities over a wide range of flame pressure, temperature, and composition. Experimentally, OH is excited by a ten nanosecond pulse from a Nd:YAG-pumped dye laser tuned to an isolated rotational transition in the (0,0) band of the A/sup 2/..sigma../sup +/-X/sup 2/ pi electronic system. The resulting fluorescence signal is resolved both spectrally and temporally. Total OH number densities are calculated by collecting fluorescence from the directly excited upper rotational level, and using the balanced cross-rate model to analyze the experimental data. Fluorescence measurements of OH number density agree to within a factor of three with the results of independent OH absorption measurements. Significantly, the ratio of the fluorescence signal to the number density measured by absorption is nearly the same in 30, 100 and 250 torr H/sub 2//O/sub 2//N/sub 2/ flat flames, demonstrating the insensitivity of the saturated fluorescence signal to the quenching environment of the radical. Collisional transfer in excited OH is studied by recording the time development of OH fluorescence spectrum. The experimental spectra are compared with the results of time-dependent computer modeling. By varying rotational transfer rates until the calculated and experimental spectra agree, rotational transfer cross sections can be calculated. The signal processing system was thoroughly checked by comparing the photomultiplier output to that of a fast photodiode, and by comparing single pulse Rayleigh scattering and fluorescence traces with sampling oscilloscope traces.

  4. Deuterium-tritium neutron yield measurements with the 4.5 m neutron-time-of-flight detectors at NIF.

    Science.gov (United States)

    Moran, M J; Bond, E J; Clancy, T J; Eckart, M J; Khater, H Y; Glebov, V Yu

    2012-10-01

    The first several campaigns of laser fusion experiments at the National Ignition Facility (NIF) included a family of high-sensitivity scintillator∕photodetector neutron-time-of-flight (nTOF) detectors for measuring deuterium-deuterium (DD) and DT neutron yields. The detectors provided consistent neutron yield (Y(n)) measurements from below 10(9) (DD) to nearly 10(15) (DT). The detectors initially demonstrated detector-to-detector Y(n) precisions better than 5%, but lacked in situ absolute calibrations. Recent experiments at NIF now have provided in situ DT yield calibration data that establish the absolute sensitivity of the 4.5 m differential tissue harmonic imaging (DTHI) detector with an accuracy of ± 10% and precision of ± 1%. The 4.5 m nTOF calibration measurements also have helped to establish improved detector impulse response functions and data analysis methods, which have contributed to improving the accuracy of the Y(n) measurements. These advances have also helped to extend the usefulness of nTOF measurements of ion temperature and downscattered neutron ratio (neutron yield 10-12 MeV divided by yield 13-15 MeV) with other nTOF detectors.

  5. Deuterium-tritium neutron yield measurements with the 4.5 m neutron-time-of-flight detectors at NIF

    Energy Technology Data Exchange (ETDEWEB)

    Moran, M. J.; Bond, E. J.; Clancy, T. J.; Eckart, M. J.; Khater, H. Y. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Glebov, V. Yu. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299 (United States)

    2012-10-15

    The first several campaigns of laser fusion experiments at the National Ignition Facility (NIF) included a family of high-sensitivity scintillator/photodetector neutron-time-of-flight (nTOF) detectors for measuring deuterium-deuterium (DD) and DT neutron yields. The detectors provided consistent neutron yield (Y{sub n}) measurements from below 10{sup 9} (DD) to nearly 10{sup 15} (DT). The detectors initially demonstrated detector-to-detector Y{sub n} precisions better than 5%, but lacked in situ absolute calibrations. Recent experiments at NIF now have provided in situ DT yield calibration data that establish the absolute sensitivity of the 4.5 m differential tissue harmonic imaging (DTHI) detector with an accuracy of {+-}10% and precision of {+-}1%. The 4.5 m nTOF calibration measurements also have helped to establish improved detector impulse response functions and data analysis methods, which have contributed to improving the accuracy of the Y{sub n} measurements. These advances have also helped to extend the usefulness of nTOF measurements of ion temperature and downscattered neutron ratio (neutron yield 10-12 MeV divided by yield 13-15 MeV) with other nTOF detectors.

  6. Inference of total DT fusion neutron yield from prompt gamma-ray measurements at the National Ignition Facility

    Science.gov (United States)

    Church, J. A.; Herrmann, H. W.; Stoeffl, W.; Caggiano, J. A.; Cerjan, C.; Sayre, D.

    2014-10-01

    Prompt D-T fusion gamma-rays measured at the National Ignition Facility (NIF) with the Gamma-ray Reaction History detector (GRH) have been used recently to infer the total DT fusion neutron yield of inertial confinement fusion (ICF) implosions. DT fusion produces energetic gamma-rays (16.75 MeV) with a small branching ratio of approximately (4.2 +/- 2.0)e-5 γ/n. While the large error bar precludes use of the branching ratio for an accurate yield determination, the gamma-rays themselves provide the most unperturbed measure of fusion burn and can be used for such a purpose. A cross-calibration for the DT fusion gamma-ray to neutron signal is obtained via low areal density exploding pusher implosions which have mostly unperturbed neutron and gamma-ray signals. The calibration is then used to infer total DT neutron yield from gamma-ray measurements on high areal-density, cryogenically layered implosions in which neutrons are heavily down-scattered (up to 30%). Furthermore, the difference between the gamma-ray inferred total DT yield and the primary neutron yield (unscattered neutrons) can be used to estimate the total down-scatter fraction. Error analysis and comparison of yield values will be presented. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344, LLNL-ABS-657694.

  7. Measurement of radiative lifetime in atomic samarium using simultaneous detection of laser-induced fluorescence and photoionization signals

    Indian Academy of Sciences (India)

    A C Sahoo; M L Shah; P K Mandal; A K Pulhani; G P Gupta; Vas Dev; B M Suri

    2014-02-01

    In this paper, we report the investigations of lifetime measurement of odd-parity energy level 19009.52 cm-1 of Sm I using simultaneous detection of laser-induced fluorescence and laserinduced photoionization signals employing pump–probe technique. To the best of our knowledge, this is for the first time that the results obtained using laser-induced fluorescence and photoionization techniques have been compared with each other. The obtained results match well with those reported in the literature.

  8. Measurements of fluorescent aerosols using a mutil-channel lidar spectrometer system during DUBI 2016 Campaign

    Science.gov (United States)

    Huang, Z.; Huang, J.; Zhou, T.; Shi, J.; Sugimoto, N.; Tang, K.

    2016-12-01

    Atmospheric bioaerosols are relevant for public health and may play an important role in the climate system. Previous studies have shown that abundant bioaerosols (such as microorganisms) injected into the atmosphere along with dust events, could affect leeward ecosystem and human health, even induce globe climate change. However, the challenge in quantifying bioaerosol climate effects (e.g., radiative forcing and aerosol-cloud interactions) arises from large spatial and temporal heterogeneity of their concentrations, compositions, sizes, shape and optical properties. Lidar, as one of most advanced active remote sensing, is used to offer some remarkable advantages for determining the vertical structure of atmospheric aerosols and their related optical properties. In order to investigate the characterization of atmospheric bioaerosols along transported pathways of dust aerosols, we carried out DUBI (DUst BIoaerosol) 2016 Campaign over Northern China in spring of 2016. Lots of instruments, including bioaerosol sampling, lidar as well as others, were installed at three sites­ (Erenhot, Zhangbei and Jinan) simultaneously. A multi-channel lidar spectrometer system was developed to observe Mie, Raman scattering and laser-induced fluorescence excitation at 355 nm from the atmosphere. The lidar system operated polarization measurements at 355nm, aiming to identify dust particles from other aerosols. It employs a high power pulsed laser with energy of 80mJ at 355nm and a received telescope with 350mm diameter. The receiver could simultaneously detect a wide fluorescent spectrum between 360nm and 720nm with spectral resolution 5.7 nm using two spectrometers simultaneously. The spectrometer mainly includes an F/3.7 Crossed Czerny-Turner spectrographs, a grating (1200 gr/mm) and a PMT array with 32 photocathode elements. Vertical structure of fluorescent aerosols in the atmosphere was observed by the developed lidar system at Zhangbei during DUBI 2016 Campaign. It has been

  9. Development of an X-ray fluorescence holographic measurement system for protein crystals

    Science.gov (United States)

    Sato-Tomita, Ayana; Shibayama, Naoya; Happo, Naohisa; Kimura, Koji; Okabe, Takahiro; Matsushita, Tomohiro; Park, Sam-Yong; Sasaki, Yuji C.; Hayashi, Kouichi

    2016-06-01

    Experimental procedure and setup for obtaining X-ray fluorescence hologram of crystalline metalloprotein samples are described. Human hemoglobin, an α2β2 tetrameric metalloprotein containing the Fe(II) heme active-site in each chain, was chosen for this study because of its wealth of crystallographic data. A cold gas flow system was introduced to reduce X-ray radiation damage of protein crystals that are usually fragile and susceptible to damage. A χ-stage was installed to rotate the sample while avoiding intersection between the X-ray beam and the sample loop or holder, which is needed for supporting fragile protein crystals. Huge hemoglobin crystals (with a maximum size of 8 × 6 × 3 mm3) were prepared and used to keep the footprint of the incident X-ray beam smaller than the sample size during the entire course of the measurement with the incident angle of 0°-70°. Under these experimental and data acquisition conditions, we achieved the first observation of the X-ray fluorescence hologram pattern from the protein crystals with minimal radiation damage, opening up a new and potential method for investigating the stereochemistry of the metal active-sites in biomacromolecules.

  10. Fluorescence lifetime measurements of native and glycated human serum albumin and bovine serum albumin

    Science.gov (United States)

    Joshi, Narahari V.; Joshi, Virgina O. d.; Contreras, Silvia; Gil, Herminia; Medina, Honorio; Siemiarczuk, Aleksander

    1999-05-01

    Nonenzymatic glycation, also known as Maillard reaction, plays an important role in the secondary complications of the diabetic pathology and aging, therefore, human serum albumin (HSA) and bovine serum albumin (BSA) were glycated by a conventional method in our laboratory using glucose as the glycating agent. Fluorescence lifetime measurements were carried out with a laser strobe fluorometer equipped with a nitrogen/dye laser and a frequency doubler as a pulsed excitation source. The samples were excited at 295 nm and the emission spectra were recorded at 345 nm. The obtained decay curves were tried for double and triple exponential functions. It has been found that the shorter lifetime increases for glycated proteins as compared with that of the native ones. For example, in the case of glycated BSA the lifetime increased from 1.36 ns to 2.30 ns. Similarly, for HSA, the lifetime increases from 1.58 ns to 2.26 ns. Meanwhile, the longer lifetime changed very slightly for both proteins (from 6.52 ns to 6.72 ns). The increase in the lifetime can be associated with the environmental effect; originated from the attachment of glucose to some lysine residues. A good example is Trp 214 which is in the cage of Lys 225, Lys 212, Lys 233, Lys 205, Lys 500, Lys 199 and Lys 195. If fluorescence lifetime technique is calibrated and properly used it could be employed for assessing glycation of proteins.

  11. Development of an X-ray fluorescence holographic measurement system for protein crystals

    Energy Technology Data Exchange (ETDEWEB)

    Sato-Tomita, Ayana, E-mail: ayana.sato@jichi.ac.jp, E-mail: shibayam@jichi.ac.jp, E-mail: hayashi.koichi@nitech.ac.jp; Shibayama, Naoya, E-mail: ayana.sato@jichi.ac.jp, E-mail: shibayam@jichi.ac.jp, E-mail: hayashi.koichi@nitech.ac.jp; Okabe, Takahiro [Division of Biophysics, Department of Physiology, Jichi Medical University, Yakushiji, Shimotsuke 329-0498 (Japan); Happo, Naohisa [Department of Computer and Network Engineering, Graduate School of Information Sciences, Hiroshima City University, Asa-Minami-Ku, Hiroshima 731-3194 (Japan); Kimura, Koji [Department of Physical Science and Engineering, Nagoya Institute of Technology, Gokiso, Showa, Nagoya 466-8555 (Japan); Matsushita, Tomohiro [Japan Synchrotron Radiation Research Institute (JASRI), SPring-8, Sayo, Hyogo 679-5198 (Japan); Park, Sam-Yong [Drug Design Laboratory, Department of Medical Life Science, Yokohama City University, Suehiro, Tsurumi, Yokohama 230-0045 (Japan); Sasaki, Yuji C. [Department of Advanced Material Science, Graduate School of Frontier Science, The University of Tokyo, Kashiwanoha, Kashiwa 277-8561 (Japan); Hayashi, Kouichi, E-mail: ayana.sato@jichi.ac.jp, E-mail: shibayam@jichi.ac.jp, E-mail: hayashi.koichi@nitech.ac.jp [Department of Physical Science and Engineering, Nagoya Institute of Technology, Gokiso, Showa, Nagoya 466-8555 (Japan); Frontier Research Institute for Materials Science, Nagoya Institute of Technology, Gokiso, Showa, Nagoya 466-8555 (Japan)

    2016-06-15

    Experimental procedure and setup for obtaining X-ray fluorescence hologram of crystalline metalloprotein samples are described. Human hemoglobin, an α{sub 2}β{sub 2} tetrameric metalloprotein containing the Fe(II) heme active-site in each chain, was chosen for this study because of its wealth of crystallographic data. A cold gas flow system was introduced to reduce X-ray radiation damage of protein crystals that are usually fragile and susceptible to damage. A χ-stage was installed to rotate the sample while avoiding intersection between the X-ray beam and the sample loop or holder, which is needed for supporting fragile protein crystals. Huge hemoglobin crystals (with a maximum size of 8 × 6 × 3 mm{sup 3}) were prepared and used to keep the footprint of the incident X-ray beam smaller than the sample size during the entire course of the measurement with the incident angle of 0°-70°. Under these experimental and data acquisition conditions, we achieved the first observation of the X-ray fluorescence hologram pattern from the protein crystals with minimal radiation damage, opening up a new and potential method for investigating the stereochemistry of the metal active-sites in biomacromolecules.

  12. Application of fluorescent tracer agent technology to point-of-care gastrointestinal permeability measurement

    Science.gov (United States)

    Dorshow, Richard B.; Shieh, Jeng-Jong; Rogers, Thomas E.; Hall-Moore, Carla; Shaikh, Nurmohammad; Talcott, Michael; Tarr, Phillip I.

    2016-03-01

    Gut dysfunction, often accompanied by increased mucosal permeability to gut contents, frequently accompanies a variety of human intestinal inflammatory conditions. These disorders include inflammatory bowel diseases (e.g., Crohn's Disease) and environmental enteropathy and enteric dysfunction, a condition strongly associated with childhood malnutrition and stunting in resource poor areas of the world. The most widely used diagnostic assay for gastrointestinal permeability is the lactulose to mannitol ratio (L:M) measurement. These sugars are administered orally, differentially absorbed by the gut, and then cleared from the body by glomerular filtration in the kidney. The amount of each sugar excreted in the urine is measured. The larger sugar, lactulose, is minimally absorbed through a healthy gut. The smaller sugar, mannitol, in contrast, is readily absorbed through both a healthy and injured gut. Thus a higher ratio of lactulose to mannitol reflects increased intestinal permeability. However, several issues prevent widespread use of the L:M ratio in clinical practice. Urine needs to be collected over time intervals of several hours, the specimen then needs to be transported to an analytical laboratory, and sophisticated equipment is required to measure the concentration of each sugar in the urine. In this presentation we show that fluorescent tracer agents with molecular weights similar to those of the sugars, selected from our portfolio of biocompatible renally cleared fluorophores, mimic the L:M ratio test for gut permeability. This fluorescent tracer agent detection technology can be used to overcome the limitations of the L:M assay, and is amenable to point-of-care clinical use.

  13. Membrane order parameters for interdigitated lipid bilayers measured via polarized total-internal-reflection fluorescence microscopy.

    Science.gov (United States)

    Ngo, An T; Jakubek, Zygmunt J; Lu, Zhengfang; Joós, Béla; Morris, Catherine E; Johnston, Linda J

    2014-11-01

    Incorporating ethanol in lipid membranes leads to changes in bilayer structure, including the formation of an interdigitated phase. We have used polarized total-internal-reflection fluorescence microscopy (pTIRFM) to measure the order parameter for Texas Red DHPE incorporated in the ethanol-induced interdigitated phase (LβI) formed from ternary lipid mixtures comprising dioleoylphosphatidylcholine, cholesterol and egg sphingomyelin or dipalmitoylphosphatidylcholine. These lipid mixtures have 3 co-existing phases in the presence of ethanol: liquid-ordered, liquid-disordered and LβI. pTIRFM using Texas Red DHPE shows a reversal in fluorescence contrast between the LβI phase and the surrounding disordered phase with changes in the polarization angle. The contrast reversal is due to changes in the orientation of the dye, and provides a rapid method to identify the LβI phase. The measured order parameters for the LβI phase are consistent with a highly ordered membrane environment, similar to a gel phase. An acyl-chain labeled BODIPY-FL-PC was also tested for pTIRFM studies of ethanol-treated bilayers; however, this probe is less useful since the order parameters of the interdigitated phase are consistent with orientations that are close to random, either due to local membrane disorder or to a mixture of extended and looping conformations in which the fluorophore is localized in the polar headgroup region of the bilayer. In summary, we demonstrate that order parameter measurements via pTIRFM using Texas Red-DHPE can rapidly identify the interdigitated phase in supported bilayers. We anticipate that this technique will aid further research in the effects of alcohols and other additives on membranes.

  14. Optical tweezers with fluorescence detection for temperature-dependent microrheological measurements.

    Science.gov (United States)

    Shundo, Atsuomi; Hori, Koichiro; Penaloza, David P; Tanaka, Keiji

    2013-01-01

    We introduce a setup of optical tweezers, capable of carrying out temperature-dependent rheological measurements of soft materials. In our setup, the particle displacement is detected by imaging a bright spot due to fluorescence emitted from a dye-labeled particle against a dark background onto a quadrant photodiode. This setup has a relatively wide space around the sample that allows us to further accessorize the optical tweezers by a temperature control unit. The applicability of the setup was examined on the basis of the rheological measurements using a typical viscoelastic system, namely a worm-like micelle solution. The temperature and frequency dependences of the local viscoelastic functions of the worm-like micelle solution obtained by this setup were in good accordance with those obtained by a conventional oscillatory rheometer, confirming the capability of the optical tweezers as a tool for the local rheological measurements of soft materials. Since the optical tweezers measurements only require a tiny amount of sample (~40 μL), the rheological measurements using our setup should be useful for soft materials of which the available amount is limited.

  15. Gamma-ray width measurements in {sup 15}N at the ELBE nuclear resonance fluorescence setup

    Energy Technology Data Exchange (ETDEWEB)

    Szuecs, Tamas [Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden (Germany); MTA ATOMKI, Debrecen/Hungary (Hungary); Bemmerer, Daniel; Schwengner, Ronald [Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden (Germany); Massarczyk, Ralph; Takacs, Marcell; Wagner, Louis [Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden (Germany); TU Dresden (Germany)

    2014-07-01

    The stable nucleus {sup 15}N is the mirror of the astrophysically important {sup 15}O, compound nucleus of the leading reaction of the Bethe-Weizsaecker cycle of hydrogen burning. Most of the {sup 15}N level widths below the neutron and proton emission thresholds are known from just one nuclear resonance fluorescence (NRF) measurement published more than 30 years ago, with unsatisfactory precision on some cases. A recent experiment with the AGATA demonstrator array aimed to determine level widths with the Doppler Shift Attenuation Method (DSAM) in {sup 15}O and {sup 15}N populated in {sup 14}N + {sup 2}H reaction. In order to set a benchmark value for the upcoming AGATA demonstrator data, the widths of several {sup 15}N levels are being studied using the bremsstrahlung facility γELBE at the electron accelerator of Helmholtz-Zentrum Dresden-Rossendorf (HZDR). The γELBE experiment and its preliminary results are presented.

  16. Feasibility of hydroxyl concentration measurements by laser-saturated fluorescence in high-pressure flames

    Science.gov (United States)

    Carter, Campbell D.; King, Galen B.; Laurendeau, Normand M.; Salmon, J. Thaddeus

    1987-01-01

    The effect of pressure on the laser-saturated fluorescence method for measuring OH concentration in high-pressure flames is studied using calculations for the burned-gas region of a stoichiometric H2-O2 flame at 2000 K. A numerical model of the excitation dynamics of OH is developed to explore the validity of the balanced cross-rate model at higher pressures. It is shown that depopulation of the laser-coupled levels is sensitive to collisions which depopulate v-double-prime (VDP) = 0 and to rate coefficients for rotational transfer in the ground state which are smaller than those in the excited state. In particular, it is shown that the depopulation of VDP = 0, and hence the laser-coupled levels, depends on the probability of electronic quenching to vibrational levels for which VDP is greater than 0 and vibrational relaxation to VDP = 0.

  17. Downsizing of Georgia Tech's Airborne Fluorescence Spectrometer (AFS) for the Measurement of Nitrogen Oxides

    Science.gov (United States)

    Sandholm, Scott

    1998-01-01

    This report addresses the Tropospheric Trace Gas and Airborne Measurements (TTGAMG) endeavors to further downsize and stabilize the Georgia Institute of Technology's Airborne Laser Induced Fluorescence Experiment (GITALIFE). It will mainly address the TTGAMG successes and failures as participants in the summer 1998 Wallops Island test flights on board the P3-B. Due to the restructuring and reorganization of the TTGAMG since the original funding of this grant, some of the objectives and time lines of the deliverables have been changed. Most of these changes have been covered in the preceding annual report. We are anticipating getting back on track with the original proposal's downsizing effort this summer, culminating in the GITALIFE no longer occupying a high bay rack and the loss of several hundred pounds.

  18. Chemometric modelling based on 2D-fluorescence spectra without a calibration measurement.

    Science.gov (United States)

    Solle, D; Geissler, D; Stärk, E; Scheper, T; Hitzmann, B

    2003-01-22

    2D fluorescence spectra provide information from intracellular compounds. Fluorophores like trytophan, tyrosine and phenylalanin as well as NADH and flavins make the corresponding measurement systems very important for bioprocess supervision and control. The evaluation is usually based on chemometric modelling using for their calibration procedure off-line measurements of the desired process variables. Due to the data driven approach lots of off-line measurements are required. Here a methodology is presented, which enables to perform a calibration procedure of chemometric models without any further measurement. The necessary information for the calibration procedure is provided by means of the a priori knowledge about the process, i.e. a mathematical model, whose model parameters are estimated during the calibration procedure, as well as the fact that the substrate should be consumed at the end of the process run. The new methodology for chemometric calibration is applied for a batch cultivation of aerobically grown S. cerevisiae on the glucose Schatzmann medium. As will be presented the chemometric models, which are determined by this method, can be used for prediction during new process runs. The MATHLAB routine is free available on request from the authors.

  19. Spectrum measurement with the Telescope Array Low Energy Extension (TALE) fluorescence detector

    Science.gov (United States)

    Zundel, Zachary James

    The Telescope Array (TA) experiment is the largest Ultra High Energy cosmic ray observatory in the northern hemisphere and is designed to be sensitive to cosmic ray air showers above 1018eV. Despite the substantial measurements made by TA and AUGER (the largest cosmic ray observatory in the southern hemisphere), there remains uncertainty about whether the highest energy cosmic rays are galactic or extragalactic in origin. Locating features in the cosmic ray energy spectrum below 1018eV that indicate a transition from galactic to extragalactic sources would clarify the interpretation of measurements made at the highest energies. The Telescope Array Low Energy Extension (TALE) is designed to extend the energy threshold of the TA observatory down to 1016.5eV in order to make such measurements. This dissertation details the construction, calibration, and operation of the TALE flu- orescence detector. A measurement of the flux of cosmic rays in the energy range of 1016.5 -- 1018.5eV is made using the monocular data set taken between September 2013 and January 2014. The TALE fluorescence detector observes evidence for a softening of the cosmic spectrum at 1017.25+/-0.5eV. The evidence of a change in the spectrum motivates continued study of 1016.5 -- 1018.5eV cosmic rays.

  20. Measurement of resistance to solute transport across surfactant-laden interfaces using a Fluorescence Recovery After Photobleaching (FRAP) technique

    Science.gov (United States)

    Browne, Edward P.; Nivaggioli, Thierry; Hatton, T. Alan

    1994-01-01

    A noninvasive fluorescence recovery after photobleaching (FRAP) technique is under development to measure interfacial transport in two phase systems without disturbing the interface. The concentration profiles of a probe solute are measured in both sides of the interface by argon-ion laser, and the system relaxation is then monitored by a microscope-mounted CCD camera.

  1. Comparison of the rate constants for energy transfer in the light-harvesting protein, C-phycocyanin, calculated from Foerster`s theory and experimentally measured by time-resolved fluorescence spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Debreczeny, M.P.

    1994-05-01

    We have measured and assigned rate constants for energy transfer between chromophores in the light-harvesting protein C-phycocyanin (PC), in the monomeric and trimeric aggregation states, isolated from Synechococcus sp. PCC 7002. In order to compare the measured rate constants with those predicted by Fdrster`s theory of inductive resonance in the weak coupling limit, we have experimentally resolved several properties of the three chromophore types ({beta}{sub 155} {alpha}{sub 84}, {beta}{sub 84}) found in PC monomers, including absorption and fluorescence spectra, extinction coefficients, fluorescence quantum yields, and fluorescence lifetimes. The cpcB/C155S mutant, whose PC is missing the {beta}{sub 155} chromophore, was, useful in effecting the resolution of the chromophore properties and in assigning the experimentally observed rate constants for energy transfer to specific pathways.

  2. Fluorescent sensors for the basic metabolic panel enable measurement with a smart phone device over the physiological range.

    Science.gov (United States)

    Awqatty, Becker; Samaddar, Shayak; Cash, Kevin J; Clark, Heather A; Dubach, J Matthew

    2014-10-21

    The advanced functionality of portable devices such as smart phones provides the necessary hardware to potentially perform complex diagnostic measurements in any setting. Recent research and development have utilized cameras and data acquisition properties of smart phones to create diagnostic approaches for a variety of diseases or pollutants. However, in concentration measurements, such as blood glucose, the performance of handheld diagnostic devices depends largely on the sensing mechanism. To expand measurements to multiple components, often necessary in medical tests, with a single diagnostic device, robust platform based sensors are needed. Here, we developed a suite of dual wavelength fluorescent sensors with response characteristics necessary to measure each component of a basic metabolic panel, a common clinical measurement. Furthermore, the response of these sensors could be measured with a simple optical setup to convert a smart phone into a fluorescence measurement instrument. This approach could be used as a mobile basic metabolic panel measurement system for point of care diagnostics.

  3. Two Photon Absorption Laser Induced Fluorescence for Neutral Hydrogen Profile Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Scime, Earl E. [West Virginia Univ., Morgantown, WV (United States)

    2016-09-23

    The magnitude and spatial dependence of neutral density in magnetic confinement fusion experiments is a key physical parameter, particularly in the plasma edge. Modeling codes require precise measurements of the neutral density to calculate charge-exchange power losses and drag forces on rotating plasmas. However, direct measurements of the neutral density are problematic. In this work, we proposed to construct a laser-based diagnostic capable of providing spatially resolved measurements of the neutral density in the edge of plasma in the DIII-D tokamak. The diagnostic concept is based on two-photon absorption laser induced fluorescence (TALIF). By injecting two beams of 205 nm light (co or counter propagating), ground state hydrogen (or deuterium or tritium) can be excited from the n = 1 level to the n = 3 level at the location where the two beams intersect. Individually, the beams experience no absorption, and therefore have no difficulty penetrating even dense plasmas. After excitation, a fraction of the hydrogen atoms decay from the n = 3 level to the n = 2 level and emit photons at 656 nm (the Hα line). Calculations based on the results of previous TALIF experiments in magnetic fusion devices indicated that a laser pulse energy of approximately 3 mJ delivered in 5 ns would provide sufficient signal-to-noise for detection of the fluorescence. In collaboration with the DIII-D engineering staff and experts in plasma edge diagnostics for DIII-D from Oak Ridge National Laboratory (ORNL), WVU researchers designed a TALIF system capable of providing spatially resolved measurements of neutral deuterium densities in the DIII-D edge plasma. The laser systems were specified, purchased, and assembled at WVU. The TALIF system was tested on a low-power hydrogen discharge at WVU and the plan was to move the instrument to DIII-D for installation in collaboration with ORNL researchers. After budget cuts at DIII-D, the DIII-D facility declined to support

  4. Imaging Spectroscopy for On-Farm Measurement of Grassland Yield and Quality

    NARCIS (Netherlands)

    Schut, A.G.T.; Heijden, van der G.W.A.M.; Hoving, I.E.; Stienezen, M.W.J.; Evert, van F.K.; Meuleman, J.

    2006-01-01

    Grassland management has a large influence on the operating cost and environmental impact of dairy farms and requires accurate, detailed, and timely information about the yield and quality of grass. Our objective was to evaluate imaging spectroscopy as a means to obtain accurate, detailed, and rapid

  5. Evaluation of measured and simulated cotton water use and yield under full and deficit irrigation

    Science.gov (United States)

    The AquaCrop model simulates crop growth, water use, yield, and water use efficiency of several crops including cotton. The model is intended to be useful for irrigation planning and management, and it attempts to balance simplicity and accuracy so that it can be applied in locations where weather a...

  6. Light yield measurements in a liquid scintillator detector with wavelength-shifting fibre readout

    CERN Document Server

    Doucet, M; Grégoire, G; Panman, J; Zucchelli, P

    2001-01-01

    A technique based on liquid scintillator with wavelength-shiftingfibre readout is interesting for large-mass neutrino detectors. In this paper, we present results obtained with a laboratoryprototype assembled at CERN. Mixtures made of economical chemicalcomponents were compared to commercial liquid scintillators. Thelight yield was also studied as a function of fibre diameter, fibreposition, and surface quality of the container.

  7. Measurement of the Branching Fraction and CP Content for the Decay B o yields D (sup asterisk +) D (sup asterisk -)

    Science.gov (United States)

    Roberts, D.

    2002-03-01

    We report a measurement of the branching fraction of the decay B o yields D (sup asterisk +) D (sup asterisk -) and of the CP-odd component of its final state using the BABAR detector. With data corresponding to an integrated luminosity of 20.4 fb to the minus 1 power collected at the gamma(4S) resonance during 1999-2000, we have reconstructed 38 candidate signal events in the mode B o yields D (sup asterisk +) D (sup asterisk -) with an estimated background of 6.2 + or - 0.5 events. From these events, we determine the branching fraction to be beta B o yields D (sup asterisk +) D (sup asterisk -) = (8.3+ or -1.6(stat) + or - 1.2(syst)) X 10 to the minus 4th power. The measured CP-odd fraction of the final state is 0.22 + or - 0.18(stat) + or - 0.03(syst).

  8. Nuclear Resonance Fluorescence to Measure Plutonium Mass in Spent Nuclear Fuel

    Energy Technology Data Exchange (ETDEWEB)

    Ludewigt, Bernhard A; Quiter, Brian J.; Ambers, Scott D.

    2011-01-14

    The Next Generation Safeguard Initiative (NGSI) of the U.S Department of Energy is supporting a multi-lab/university collaboration to quantify the plutonium (Pu) mass in spent nuclear fuel (SNF) assemblies and to detect the diversion of pins with non-destructive assay (NDA) methods. The following 14 NDA techniques are being studied: Delayed Neutrons, Differential Die-Away, Differential Die-Away Self-Interrogation, Lead Slowing Down Spectrometer, Neutron Multiplicity, Passive Neutron Albedo Reactivity, Total Neutron (Gross Neutron), X-Ray Fluorescence, {sup 252}Cf Interrogation with Prompt Neutron Detection, Delayed Gamma, Nuclear Resonance Fluorescence, Passive Prompt Gamma, Self-integration Neutron Resonance Densitometry, and Neutron Resonance Transmission Analysis. Understanding and maturity of the techniques vary greatly, ranging from decades old, well-understood methods to new approaches. Nuclear Resonance Fluorescence (NRF) is a technique that had not previously been studied for SNF assay or similar applications. Since NRF generates isotope-specific signals, the promise and appeal of the technique lies in its potential to directly measure the amount of a specific isotope in an SNF assay target. The objectives of this study were to design and model suitable NRF measurement methods, to quantify capabilities and corresponding instrumentation requirements, and to evaluate prospects and the potential of NRF for SNF assay. The main challenge of the technique is to achieve the sensitivity and precision, i.e., to accumulate sufficient counting statistics, required for quantifying the mass of Pu isotopes in SNF assemblies. Systematic errors, considered a lesser problem for a direct measurement and only briefly discussed in this report, need to be evaluated for specific instrument designs in the future. Also, since the technical capability of using NRF to measure Pu in SNF has not been established, this report does not directly address issues such as cost, size

  9. Absolute prompt-gamma yield measurements for ion beam therapy monitoring

    Science.gov (United States)

    Pinto, M.; Bajard, M.; Brons, S.; Chevallier, M.; Dauvergne, D.; Dedes, G.; De Rydt, M.; Freud, N.; Krimmer, J.; La Tessa, C.; Létang, J. M.; Parodi, K.; Pleskač, R.; Prieels, D.; Ray, C.; Rinaldi, I.; Roellinghoff, F.; Schardt, D.; Testa, E.; Testa, M.

    2015-01-01

    Prompt-gamma emission detection is a promising technique for hadrontherapy monitoring purposes. In this regard, obtaining prompt-gamma yields that can be used to develop monitoring systems based on this principle is of utmost importance since any camera design must cope with the available signal. Herein, a comprehensive study of the data from ten single-slit experiments is presented, five consisting in the irradiation of either PMMA or water targets with lower and higher energy carbon ions, and another five experiments using PMMA targets and proton beams. Analysis techniques such as background subtraction methods, geometrical normalization, and systematic uncertainty estimation were applied to the data in order to obtain absolute prompt-gamma yields in units of prompt-gamma counts per incident ion, unit of field of view, and unit of solid angle. At the entrance of a PMMA target, where the contribution of secondary nuclear reactions is negligible, prompt-gamma counts per incident ion, per millimetre and per steradian equal to (124 ± 0.7stat ± 30sys) × 10-6 for 95 MeV u-1 carbon ions, (79 ± 2stat ± 23sys) × 10-6 for 310 MeV u-1 carbon ions, and (16 ± 0.07stat ± 1sys) × 10-6 for 160 MeV protons were found for prompt gammas with energies higher than 1 MeV. This shows a factor 5 between the yields of two different ions species with the same range in water (160 MeV protons and 310 MeV u-1 carbon ions). The target composition was also found to influence the prompt-gamma yield since, for 300/310 MeV u-1 carbon ions, a 42% greater yield ((112 ± 1stat ± 22sys) × 10-6 counts ion-1 mm-1 sr-1) was obtained with a water target compared to a PMMA one.

  10. Measurement of the hydrodynamic radius of quantum dots by fluorescence correlation spectroscopy excluding blinking.

    Science.gov (United States)

    de Thomaz, A A; Almeida, D B; Pelegati, V B; Carvalho, H F; Cesar, C L

    2015-03-19

    One of the most important properties of quantum dots (QDs) is their size. Their size will determine optical properties and in a colloidal medium their range of interaction. The most common techniques used to measure QD size are transmission electron microscopy (TEM) and X-ray diffraction. However, these techniques demand the sample to be dried and under a vacuum. This way any hydrodynamic information is excluded and the preparation process may alter even the size of the QDs. Fluorescence correlation spectroscopy (FCS) is an optical technique with single molecule sensitivity capable of extracting the hydrodynamic radius (HR) of the QDs. The main drawback of FCS is the blinking phenomenon that alters the correlation function implicating in a QD apparent size smaller than it really is. In this work, we developed a method to exclude blinking of the FCS and measured the HR of colloidal QDs. We compared our results with TEM images, and the HR obtained by FCS is higher than the radius measured by TEM. We attribute this difference to the cap layer of the QD that cannot be seen in the TEM images.

  11. Fluorescence (TALIF) measurement of atomic hydrogen concentration in a coplanar surface dielectric barrier discharge

    Science.gov (United States)

    Mrkvičková, M.; Ráheľ, J.; Dvořák, P.; Trunec, D.; Morávek, T.

    2016-10-01

    Spatially and temporally resolved measurements of atomic hydrogen concentration above the dielectric of coplanar barrier discharge are presented for atmospheric pressure in 2.2% H2/Ar. The measurements were carried out in the afterglow phase by means of two-photon absorption laser-induced fluorescence (TALIF). The difficulties of employing the TALIF technique in close proximity to the dielectric surface wall were successfully addressed by taking measurements on a suitable convexly curved dielectric barrier, and by proper mathematical treatment of parasitic signals from laser-surface interactions. It was found that the maximum atomic hydrogen concentration is situated closest to the dielectric wall from which it gradually decays. The maximum absolute concentration was more than 1022 m-3. In the afterglow phase, the concentration of atomic hydrogen above the dielectric surface stays constant for a considerable time (10 μs-1 ms), with longer times for areas situated farther from the dielectric surface. The existence of such a temporal plateau was explained by the presented 1D model: the recombination losses of atomic hydrogen farther from the dielectric surface are compensated by the diffusion of atomic hydrogen from regions close to the dielectric surface. The fact that a temporal plateau exists even closest to the dielectric surface suggests that the dielectric surface acts as a source of atomic hydrogen in the afterglow phase.

  12. Improved Branching Ratio Measurement for the Decay K{sup 0}{sub L} {yields} {mu}{sup +} {mu}{sup -}

    Energy Technology Data Exchange (ETDEWEB)

    Ambrose, D. [University of Texas, Austin, Texas 78712 (United States); Arroyo, C. [Stanford University, Stanford, California 94305 (United States); Bachman, M. [University of California, Irvine, California 92697 (United States); Connor, D. [University of California, Irvine, California 92697 (United States); Eckhause, M. [College of William and Mary, Williamsburg, Virginia 23187 (United States); Graessle, S. [University of Texas, Austin, Texas 78712 (United States); Hancock, A. D. [College of William and Mary, Williamsburg, Virginia 23187 (United States); Hartman, K. [Stanford University, Stanford, California 94305 (United States); Hebert, M. [Stanford University, Stanford, California 94305 (United States); Hoff, C. H. [College of William and Mary, Williamsburg, Virginia 23187 (United States)] (and others)

    2000-02-14

    We report results from Experiment 871, performed at the BNL AGS, of a measurement of the branching ratio K{sup 0}{sub L}{yields}{mu}{sup +}{mu}{sup -} with respect to the CP -violating mode K{sup 0}{sub L}{yields}{pi}{sup +}{pi}{sup -} . This experiment detected over 6200 candidate {mu}{sup +}{mu}{sup -} events, a factor of 6 more than that seen in all previous measurements combined. The resulting branching ratio {gamma}(K{sup 0}{sub L}{yields}{mu}{sup +} {mu}{sup -})/{gamma}(K{sup 0}{sub L}{yields}{pi}{sup +}{pi}{sup -}) (3.474{+-}0.057)x10{sup -6} leads to a branching fraction B(K{sup 0}{sub L}{yields}{mu}{sup +}{mu}{sup -})=(7.18{+-}0.17)x10{sup -9} , which is consistent with the current world average, and reduces the uncertainty in this decay mode by a factor of 3. (c) 2000 The American Physical Society.

  13. Intercomparison of peroxy radical measurements obtained at atmospheric conditions by laser-induced fluorescence and electron spin resonance spectroscopy

    Directory of Open Access Journals (Sweden)

    A. Hofzumahaus

    2009-03-01

    Full Text Available Measurements of hydroperoxy radical (HO2 and organic peroxy radical (RO2 concentrations were performed by two different techniques in the atmospheric simulation chamber SAPHIR in Jülich, Germany. The first technique was the well-established Matrix Isolation Electron Spin Resonance (MIESR, which provides absolute measurements with a time resolution of 30 min and high accuracy (10%, 2 σ. The other technique, ROxLIF, has been newly developed. It is based on the selective chemical conversion of ROx radicals (HO2 and RO2 to OH, which is detected with high sensitivity by laser-induced fluorescence (LIF. ROxLIF is calibrated by quantitative photolysis of water vapor at 185 nm and provides ambient measurements at a temporal resolution of 1 min and accuracy of 20% (2 σ. The measurements of HO2 and RO2 obtained by the two techniques were compared for two types of atmospheric simulation experiments. In one experiment, HO2 and CH3O2 radicals were produced by photooxidation of methane in air at tropospheric conditions. In the second experiment, HO2 and C2H5O2 were produced by ozonolysis of 1-butene in air at dark conditions. The radical concentrations were within the range of 16 to 100 pptv for HO2 and 12 to 45 pptv for RO2. Good agreement was found in the comparison of the ROxLIF and MIESR measurements within their combined experimental uncertainties. Linear regressions to the combined data set yield slopes of 1.02±0.13 (1 σ for RO2 and 0.98±0.08 (1 σ for HO2 without significant offsets. The results confirm the calibration of the ROxLIF instrument and demonstrate that it can be applied with good accuracy for measurements of atmospheric peroxy radical concentrations.

  14. MeV-SIMS yield measurements using a Si-PIN diode as a primary ion current counter

    Energy Technology Data Exchange (ETDEWEB)

    Stoytschew, Valentin; Bogdanović Radović, Iva [Ruđer Bošković Institute, Zagreb (Croatia); Demarche, Julien [University of Surrey, Surrey (United Kingdom); Jakšić, Milko [Ruđer Bošković Institute, Zagreb (Croatia); Matjačić, Lidija [University of Surrey, Surrey (United Kingdom); Siketić, Zdravko [Ruđer Bošković Institute, Zagreb (Croatia); Webb, Roger [University of Surrey, Surrey (United Kingdom)

    2016-03-15

    Megaelectronvolt-Secondary Ion Mass Spectrometry (MeV-SIMS) is an emerging Ion Beam Analysis technique for molecular speciation and submicron imaging. Various setups have been constructed in the recent years. Still a systematic investigation on the dependence of MeV-SIMS yields on different ion beam parameters is missing. A reliable measurement method of the beam current down to the attoampere range is needed for this investigation. Therefore, a new detector has been added to the MeV-SIMS setup at the Ruđer Bošković Institute (RBI), which measures the current directly using a Si PIN-diode. In this work, we present the constructed system, its characteristics, and results of the first yield measurements. These measurements have already identified important factors that have to be considered while constructing a MeV SIMS setup.

  15. Monitoring of labeled antisense oligonucleotides within living cells by using a multifrequency phase/modulation approach for fluorescence lifetime measurements

    Science.gov (United States)

    Kocisova, E.; Sureau, F.; Praus, P.; Rosenberg, I.; Stepanek, J.; Turpin, P.-Y.

    2003-06-01

    A multifrequency phase/modulation method has been developed for our UV confocal laser microspectrofluorimeter (modulation frequency 1-200 MHz) for fluorescence lifetime measurements. This technique enables excited state lifetimes of mixed fluorescent components to be resolved and the fluorescence spectral contribution of each species to be determined without using any model spectra. This approach is very efficient for analyzing intracellular multicomponent fluorescence signals. Our effort is focused on the elucidation of the intracellular behavior of synthetic modified oligonucleotides - potential drugs for antisense and/or antigene strategies of curing viral and malignant diseases. A novel type single stranded dT 15 oligomer analogue containing isopolar, non-isosteric, phosphonate-based internucleotide linkages (3'-O-P-CH 2-O-5'), labeled with tetramethylrhodamine dye at the 3'-end, has been utilized. This method, along with fluorescence micro-imaging, was used to monitor uptake, distribution and stability of our modified oligonucleotide inside living cells. Binding to Escort™ vector leads to an homogeneous intracellular distribution of fluorescent labeled oligonucleotide, including nucleus staining, while point distribution only is achieved for its free form.

  16. Diurnal feeding rhythms in north sea copepods measured by Gut fluorescence, digestive enzyme activity and grazing on labelled food

    Science.gov (United States)

    Baars, M. A.; Oosterhuis, S. S.

    Results obtained with three methods for measuring feeding rhythms of copepods were different. Gut fluorescence showed clear day-night variation during 2 out of 3 cruises at the Oyster Ground in the North Sea. The species studied ( Pseudocalanus, Temora, Centropages, Calanus) had highest gut fluorescence during the night in May and September, the larger species demonstrating the largest difference. Gut fluorescence was positively correlated with ambient chlorophyll concentrations. Gut clearance rate was not dependent on temperature but on gut fullness. Gut passage times at high gut fluorescence levels were ˜25 minutes, at low levels 2 hours. In grazing experiments with 14C labelled food, filtering rates declined after 5 to 15 minutes, presumably before the first defecation of radioactive material. Filtering rates in Temora were higher at night than by day during May and July, but not in Pseudocalanus and Calanus during September. No diurnal pattern of amylase and tryptic activity was found, except in July for amylase but then probably due to vertical migration. The activity of these digestive enzymes appeared to be least and gut fluorescence most suitable for the detection of grazing rhythms. The occurrence of high fluorescence levels at night in all species studied suggests that intermittent feeding by copepods on phytoplankton is a general phenomenon from spring to autumn. The increase in foraging activity appeared to start well before complete darkness, during May and July even one hour or more before sunset.

  17. Photolysis quantum yield measurements in the near-UV; a critical analysis of 1-(2-nitrophenyl)ethyl photochemistry.

    Science.gov (United States)

    Corrie, John E T; Kaplan, Jack H; Forbush, Biff; Ogden, David C; Trentham, David R

    2016-05-11

    The photolysis quantum yield, Qp, of 1-(2-nitrophenyl)ethyl phosphate (caged Pi) measured in the near-UV (342 nm peak with 60 nm half-bandwidth) is 0.53 and is based on results reported in 1978 (Biochemistry, 17, 1929-1935). This article amplifies methodology for determining that Qp in view of different recent estimates. Some general principles together with other examples relating to measurement of Qp values are discussed together with their relevance to biological research.

  18. Lithium: Measurement of Young's Modulus and Yield Strength

    Energy Technology Data Exchange (ETDEWEB)

    Ryan P Schultz

    2002-11-07

    The Lithium Collection Lens is used for anti-proton collection. In analyzing the structural behavior during operation, various material properties of lithium are often needed. properties such as density, coefficient of thermal expansion, thermal conductivity, specific heat, compressability, etc.; are well known. However, to the authors knowledge there is only one published source for Young's Modulus. This paper reviews the results from the testing of Young's Modulus and the yield strength of lithium at room temperature.

  19. Measuring K{sup +} {yields} {pi}{sup +}{nu}{nu}-bar and K{sub L}{sup 0} {yields} {pi}{sup 0}{nu}{nu}-bar at BNL

    Energy Technology Data Exchange (ETDEWEB)

    Bryman, D.A. [Univ. of British Columbia, Dept. of Physics and Astronomy, Vancouver, British Columbia (Canada)]|[TRIUMF, Vancouver, British Columbia (Canada)

    2001-07-01

    K{sup +} {yields}{pi}{sup +}{nu}{nu}-bar and K{sub L}{sup 0} {yields} {pi}{sup 0}{nu}{nu}-bar are ultra-rare kaon decay channels which offer unique opportunities for measuring Standard Model parameters relating to quark mixing and CP violation as well as searching for new physics. In this paper, the prospects for current and future progress on measuring K{sup +} {yields}{pi}{sup +}{nu}{nu}-bar and K{sub L}{sup 0} {yields} {pi}{sup 0}{nu}{nu}-bar at the Brookhaven AGS are reported. (author)

  20. Green and ultraviolet pulse generation with a compact, fiber laser, chirped-pulse amplification system for aerosol fluorescence measurements

    Science.gov (United States)

    Lou, Janet W.; Currie, Marc; Sivaprakasam, Vasanthi; Eversole, Jay D.

    2010-10-01

    We use a compact chirped-pulse amplified system to harmonically generate ultrashort pulses for aerosol fluorescence measurements. The seed laser is a compact, all-normal dispersion, mode-locked Yb-doped fiber laser with a 1050 nm center wavelength operating at 41 MHz. Average powers of more than 1.2 W at 525 nm and 350 mW at 262 nm are generated with biofluorescence measurements as it allows faster sampling rates as well as the higher peak powers as compared to previously demonstrated Q-switched systems while maintaining a pulse period that is longer than the typical fluorescence lifetimes. Thus, the fluorescence excitation can be considered to be quasicontinuous and requires no external synchronization and triggering.

  1. Isotope shifts of natural Sr+ measured by laser fluorescence in a sympathetically cooled Coulomb crystal

    CERN Document Server

    Dubost, Brice; Szymanski, Benjamin; Guibal, Samuel; Likforman, Jean-Pierre; Guidoni, Luca

    2014-01-01

    We measured by laser spectroscopy the isotope shifts between naturally-occurring even-isotopes of strontium ions for both the $5s\\,\\,^2S_{1/2}\\to 5p\\,\\,^2P_{1/2}$ (violet) and the $4d\\,\\,^2D_{3/2}\\to 5p\\,\\,^2P_{1/2}$ (infrared) dipole-allowed optical transitions. Fluorescence spectra were taken by simultaneous measurements on a two-component Coulomb crystal in a linear Paul trap containing $10^3$--$10^4$ laser-cooled Sr$^+$ ions. The isotope shifts are extracted from the experimental spectra by fitting the data with the analytical solution of the optical Bloch equations describing a three-level atom in interaction with two laser beams. This technique allowed us to increase the precision with respect to previously reported data obtained by optogalvanic spectroscopy or fast atomic-beam techniques. The results for the $5s\\,\\,^2S_{1/2}\\to 5p\\,\\,^2P_{1/2}$ transition are $\

  2. Measurements of noninterceptive fluorescence profile monitor prototypes using 9 MeV deuterons

    Directory of Open Access Journals (Sweden)

    J. M. Carmona

    2012-07-01

    Full Text Available Two types of noninterceptive optical monitors, based on gas fluorescence, have been designed for use on the Linear IFMIF Prototype Accelerator (LIPAc that is currently under development (a 125 mA, 9 MeV, 175 MHz continuous wave deuteron beam. These diagnostics offer a technique to characterize the transverse beam profile for medium to high current hadron beams, without intercepting the beam core. This paper reports on beam tests using the prototype monitors developed for LIPAc. Tests were carried out at an experimental line of the Centro Nacional de Aceleradores cyclotron, using 9 MeV deuterons with beam currents from 0.4 to 40  μA. In addition, transverse beam profile measurements were performed under high background radiation (e.g. gamma dose rate up to 83  mSv/h. Preliminary cross-checks with different profilers, as well as a systematic scan of beam current and vacuum pressures and tests with different injected gases (nitrogen and xenon have been performed. In this work, we present a brief description of the experimental setup and the first measurements obtained with these prototype profilers plus a discussion of the first analysis of the background signal in a detector as a function of radiation background.

  3. Measurement of fuel corrosion products using planar laser-induced fluorescence

    Science.gov (United States)

    Wantuck, Paul J.; Sappey, Andrew D.; Butt, Darryl P.

    1993-01-01

    Characterizing the corrosion behavior of nuclear fuel material in a high-temperature hydrogen environment is critical for ascertaining the operational performance of proposed nuclear thermal propulsion (NTP) concepts. In this paper, we describe an experimental study undertaken to develop and test non-intrusive, laser-based diagnostics for ultimately measuring the distribution of key gas-phase corrosion products expected to evolve during the exposure of NTP fuel to hydrogen. A laser ablation technique is used to produce high temperature, vapor plumes from uranium-free zirconium carbide (ZrC) and niobium carbide (NbC) forms for probing by various optical diagnostics including planar laser-induced fluorescence (PLIF). We discuss the laser ablation technique, results of plume emission measurements, and we describe both the actual and proposed planar LIF schemes for imaging constituents of the ablated ZrC and NbC plumes. Envisioned testing of the laser technique in rf-heated, high temperature gas streams is also discussed.

  4. Flow Property Measurement Using Laser-Induced Fluorescence in the NASA Ames Interaction Heating Facility

    Science.gov (United States)

    Grinstead, Jay Henderson; Porter, Barry J.; Carballo, Julio Enrique

    2011-01-01

    The spectroscopic diagnostic technique of two photon absorption laser-induced fluorescence (TALIF) of atomic species has been applied to single-point measurements of velocity and static temperature in the NASA Ames Interaction Heating Facility (IHF) arc jet. Excitation spectra of atomic oxygen and nitrogen were recorded while scanning a tunable dye laser over the absorption feature. Thirty excitation spectra were acquired during 8 arc jet runs at two facility operating conditions; the number of scans per run varied between 2 and 6. Curve fits to the spectra were analyzed to recover their Doppler shifts and widths, from which the flow velocities and static temperatures, respectively, were determined. An increase in the number of independent flow property pairs from each as-measured scan was obtained by extracting multiple lower-resolution scans. The larger population sample size enabled the mean property values and their uncertainties for each run to be characterized with greater confidence. The average plus or minus 2 sigma uncertainties in the mean velocities and temperatures for all 8 runs were plus or minus 1.4% and plus or minus 11%, respectively.

  5. A new total antioxidant potential measurements using RP-HPLC assay with fluorescence detection.

    Science.gov (United States)

    Głód, Bronisław K; Piszcz, Paweł; Czajka, Katarzyna; Zarzycki, Paweł K

    2011-05-01

    In this paper, an improved total antioxidant potential (TAP) estimation using high-performance liquid chromatographic (HPLC) assay with fluorometric detection has been described. The principle of this method is based on the hydroxyl radicals generated in the Fenton-like reaction and subsequently detected using hydroxyterephthalic acid (HTPA), which is a reaction product of hydroxyl radicals and terephthalic acid (TPA), working as a sensing compound. HTPA quantity in the samples was measured by fluorescence detector working at excitation and emission wavelengths equal to 312 and 428 nm, respectively. A number of key experimental conditions including the influence of the reaction (incubation) time on the surface areas of HTPA peaks, concentration of Fe(II) ions as well as the influence of concentration of TPA on the surface area of the chromatographic peak of HTPA were optimized to the characteristic feature of TAP measurements. The elaborated assay has been used to evaluate TAP values of selected low-molecular mass compounds like pyrogallol, tryptamine, and n-alcohols (methanol, ethanol, and n-propanol) as well as chlorogenic and ascorbic acids and benzoic acid derivatives, which are commonly present in the food samples.

  6. Fluorescence competition assay measurements of free energy changes for RNA pseudoknots.

    Science.gov (United States)

    Liu, Biao; Shankar, Neelaabh; Turner, Douglas H

    2010-01-26

    RNA pseudoknots have important functions, and thermodynamic stability is a key to predicting pseudoknots in RNA sequences and to understanding their functions. Traditional methods, such as UV melting and differential scanning calorimetry, for measuring RNA thermodynamics are restricted to temperature ranges around the melting temperature for a pseudoknot. Here, we report RNA pseudoknot free energy changes at 37 degrees C measured by fluorescence competition assays. Sequence-dependent studies for the loop 1-stem 2 region reveal (1) the individual nearest-neighbor hydrogen bonding (INN-HB) model provides a reasonable estimate for the free energy change when a Watson-Crick base pair in stem 2 is changed, (2) the loop entropy can be estimated by a statistical polymer model, although some penalty for certain loop sequences is necessary, and (3) tertiary interactions can significantly stabilize pseudoknots and extending the length of stem 2 may alter tertiary interactions such that the INN-HB model does not predict the net effect of adding a base pair. The results can inform writing of algorithms for predicting and/or designing RNA secondary structures.

  7. Nuclear Resonance Fluorescence Measurements on ^237Np for Security and Safeguards Applications

    Science.gov (United States)

    Angell, C. T.; Joshi, T.; Yee, Ryan; Norman, E. B.; Kulp, W. D.; Warren, G. A.; Korbly, S.; Klimenko, A.; Wilson, C.; Copping, R.; Shuh, D. K.

    2009-10-01

    The smuggling of nuclear material and the diversion of fissile material for covert weapon programs both present grave risks to world security. Methods are needed to detect nuclear material smuggled in cargo, and for proper material accountability in civilian fuel re-processing facilities. Nuclear resonance fluorescence (NRF) is a technique that can address both needs. It is a non-destructive active interrogation method that provides isotope-specific information. It works by using a γ-ray beam to resonantly excite levels in a nucleus and observing the γ-rays emitted whose energy and intensity are characteristic of that isotope. ^237Np presents significant safeguard challenges; it is fissile yet currently has fewer safeguard restrictions. NRF measurements on ^237Np will expand the nuclear database and will permit designing interrogation and assay systems. Measurements were made using the bremsstrahlung beam at the HVRL at MIT on a 7 g target of ^237Np with two incident electron energies of 2.8 and 3.1 MeV. Results will be presented with discussion of the relevant nuclear structure necessary to predict levels in other actinides.

  8. Fluorescence spectra of atmospheric aerosol at Adelphi, Maryland, USA: measurement and classification of single particles containing organic carbon

    Science.gov (United States)

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

    We measured laser-induced fluorescence spectra from individual supermicron-sized atmospheric particles drawn into our laboratory at Adelphi, MD, an urban site in the Washington, DC metroplex. A virtural impactor concentrator is used along with an aerodynamic-focusing-nozzle which forms, within an optical chamber, a focused aerosol jet where single aerosol particles can be interrogated on-the-fly with a pulsed 266-nm-wavelength laser. Sample rates are a few liter per minute, and are size dependent. Crossed-diode laser beams indicate when a particle is traversing the sample region and are used to trigger the UV laser to fire and the gated intensified CCD to record the fluorescence spectrum. Our breadboard fluorescence particle spectrometer measures particles in the 3-10 μm diameter size range. Typical trigger rates are a few per second. The usable spectral range is from about 295 to 605 nm. The majority of the particles have very weak fluorescence (on average 8 percent of particles have fluorescence signals above noise). The spectra were grouped using a heirarchical cluster analysis, with parameters chosen so that spectra typically cluster into 4-12 main categories. From the set of all cluster spectra we chose 8 template spectra for reanalyzing all the data. On average, 92 percent (81-94 percent) of the spectra were similar to these templates (using the same thresholds used for the cluster analysis). The major emission bands of the most commonly occurring spectra have peaks: near 460 nm (28 percent of fluorescent particles on average), a very broad hump, and may be humic acids or humic like substances; near 317 nm (on average 24 percent of fluorescent particles); near 321 and 460 nm (a double hump, 12 percent of fluorescent particles); and near 341 nm (8 percent of fluorescent particles). Some of the fluorescence in spectra peaking in the 317-341 nm range is probably from dicyclic aromatics and heterocyclics, including the amino acid tryptophan in biological

  9. A Starting Point for Fluorescence-Based Single-Molecule Measurements in Biomolecular Research

    Directory of Open Access Journals (Sweden)

    Alexander Gust

    2014-09-01

    Full Text Available Single-molecule fluorescence techniques are ideally suited to provide information about the structure-function-dynamics relationship of a biomolecule as static and dynamic heterogeneity can be easily detected. However, what type of single-molecule fluorescence technique is suited for which kind of biological question and what are the obstacles on the way to a successful single-molecule microscopy experiment? In this review, we provide practical insights into fluorescence-based single-molecule experiments aiming for scientists who wish to take their experiments to the single-molecule level. We especially focus on fluorescence resonance energy transfer (FRET experiments as these are a widely employed tool for the investigation of biomolecular mechanisms. We will guide the reader through the most critical steps that determine the success and quality of diffusion-based confocal and immobilization-based total internal reflection fluorescence microscopy. We discuss the specific chemical and photophysical requirements that make fluorescent dyes suitable for single-molecule fluorescence experiments. Most importantly, we review recently emerged photoprotection systems as well as passivation and immobilization strategies that enable the observation of fluorescently labeled molecules under biocompatible conditions. Moreover, we discuss how the optical single-molecule toolkit has been extended in recent years to capture the physiological complexity of a cell making it even more relevant for biological research.

  10. Fluorescently labeled cyclodextrin derivatives as exogenous markers for real-time transcutaneous measurement of renal function

    NARCIS (Netherlands)

    Huang, Jiaguo; Weinfurter, Stefanie; Pinto, Pedro Caetano; Pretze, Marc; Kränzlin, Bettina; Pill, Johannes; Federica, Rodeghiero; Perciaccante, Rossana; Ciana, Leopoldo Della; Masereeuw, Rosalinde; Gretz, Norbert

    2016-01-01

    Evaluation of renal function is crucial for a number of clinical situations. Here, we reported a novel exogenous fluorescent marker (FITC-HPβCD) to real-time assess renal function by using a transcutaneous fluorescent detection technique. FITC-HPβCD was designed based on the principle of renal

  11. Fluorescently Labeled Cyclodextrin Derivatives as Exogenous Markers for Real-Time Transcutaneous Measurement of Renal Function

    NARCIS (Netherlands)

    Huang, J.; Weinfurter, S.; Pinto, P.C.; Pretze, M.; Kranzlin, B.; Pill, J.; Federica, R.; Perciaccante, R.; Ciana, L.D.; Masereeuw, R.; Gretz, N.

    2016-01-01

    Evaluation of renal function is crucial for a number of clinical situations. Here, we reported a novel exogenous fluorescent marker (FITC-HPbetaCD) to real-time assess renal function by using a transcutaneous fluorescent detection technique. FITC-HPbetaCD was designed based on the principle of renal

  12. Ultrafast polarized fluorescence measurements on monomeric and self-associated melittin

    NARCIS (Netherlands)

    Pandit, A.; Larsen, O.F.A.; Stokkum, van I.H.M.; Grondelle, van R.; Kraayenhof, R.; Amerongen, van H.

    2003-01-01

    The anisotropic and magic-angle fluorescence decay of the single tryptophan (Trp) residue of melittin, a bee venom peptide, was investigated by time-resolved fluorescence anisotropy using a streak camera setup. The peptide was dissolved either in distilled water or in Hepes/NaOH buffer containing lo

  13. A starting point for fluorescence-based single-molecule measurements in biomolecular research.

    Science.gov (United States)

    Gust, Alexander; Zander, Adrian; Gietl, Andreas; Holzmeister, Phil; Schulz, Sarah; Lalkens, Birka; Tinnefeld, Philip; Grohmann, Dina

    2014-09-30

    Single-molecule fluorescence techniques are ideally suited to provide information about the structure-function-dynamics relationship of a biomolecule as static and dynamic heterogeneity can be easily detected. However, what type of single-molecule fluorescence technique is suited for which kind of biological question and what are the obstacles on the way to a successful single-molecule microscopy experiment? In this review, we provide practical insights into fluorescence-based single-molecule experiments aiming for scientists who wish to take their experiments to the single-molecule level. We especially focus on fluorescence resonance energy transfer (FRET) experiments as these are a widely employed tool for the investigation of biomolecular mechanisms. We will guide the reader through the most critical steps that determine the success and quality of diffusion-based confocal and immobilization-based total internal reflection fluorescence microscopy. We discuss the specific chemical and photophysical requirements that make fluorescent dyes suitable for single-molecule fluorescence experiments. Most importantly, we review recently emerged photoprotection systems as well as passivation and immobilization strategies that enable the observation of fluorescently labeled molecules under biocompatible conditions. Moreover, we discuss how the optical single-molecule toolkit has been extended in recent years to capture the physiological complexity of a cell making it even more relevant for biological research.

  14. Measure of the e+e-{yields}bb Cross Section at the LEP Energies; Medida de la seccion eficaz e''+e''-{yields}bb a las Energias de LEP

    Energy Technology Data Exchange (ETDEWEB)

    Arce Dubois, P.

    1992-07-01

    In the present work I analyse the data collected during 1990 by the L3 detector, situated in the electron-positron collider LEP. After selecting the events e''+e''-{yields} bb through their semileptonic decays into muons, I calculate the cross section for the process e''+e''- {yields} bb at different energy points around the mass of the vectorial boson Z, and I measure some parameters of the Standard Model, namely, the Br(b{yields}{mu} ),{gamma}{sub z}n-{yields}bb/{gamma}{sub z}n{yields}had and {gamma}{sub z}n{yields}bb{gamma}{sub z}n{yields}e''+e''-. (Author) 26 refs.

  15. X-Ray Diffraction and Fluorescence Measurements for In-situ Planetary Instruments

    Science.gov (United States)

    Hansford, G.; Hill, K. S.; Vernon, D.; Ambrosi, R. M.; Bridges, J.; Hutchinson, I.

    2010-12-01

    The X-Ray Diffraction (XRD) instruments are core components of the forthcoming NASA Mars Science Laboratory (MSL) and ESA/NASA EXOMARS missions and will provide the first demonstrations of an XRF/XRD instrument’s capabilities in-situ on an extraterrestrial planetary surface. The University of Leicester team is part of the Italy-UK collaboration that is responsible for building the ExoMars X-Ray Diffraction instrument, Mars XRD. The ExoMars X-ray diffraction instrument incorporates an 55-Fe radioisotope source and three fixed-position CCDs to simultaneously acquire an X-Ray fluorescence spectrum and a diffraction pattern providing a measurement of both elemental and mineralogical composition [1]. The CCDs cover an angular range from 6 to 65-deg enabling the analysis of silicates, from clays, or other phyllosilicates characterised by varying d-spacings, to oxides, and carbonates or evaporites. The identification of hydrous minerals may help identify past Martian hydrothermal systems capable of preserving traces of life. Here we present some initial findings from XRF and XRD tests carried out at the University of Leicester using an 55-Fe source and X-ray sensitive CCD [1]. The XRD/XRD test system consists of a single CCD on a motorised arm, an 55-Fe X-ray source, source collimator and a sample table which approximately replicate the reflection geometry of the XRD instrument. It was used to test geological reference standard materials and Martian analogues. Incidence angle and CCD angles on both the diffraction and fluorescence results were evaluated. A key area of interest is the effect of sample roughness on the XRD/XRF results. We present results from testing pressed powder pellet samples of varying surface roughness, and a comparison with model results [2]. So far we have found that increased roughness causes a reduced intensity at lower take-off angles. Several methods for measuring surface roughness of the samples have been used including an Alicona Infinite

  16. Measuring Norfloxacin Binding to Trypsin Using a Fluorescence Quenching Assay in an Upper-Division, Integrated Laboratory Course

    Science.gov (United States)

    Hicks, Katherine A.

    2016-01-01

    Fluorescence quenching assays are often used to measure dissociation constants that quantify the binding affinity between small molecules and proteins. In an upper-division undergraduate laboratory course, where students work on projects using a guided inquiry-based approach, a binding titration experiment at physiological pH is performed to…

  17. Measuring Norfloxacin Binding to Trypsin Using a Fluorescence Quenching Assay in an Upper-Division, Integrated Laboratory Course

    Science.gov (United States)

    Hicks, Katherine A.

    2016-01-01

    Fluorescence quenching assays are often used to measure dissociation constants that quantify the binding affinity between small molecules and proteins. In an upper-division undergraduate laboratory course, where students work on projects using a guided inquiry-based approach, a binding titration experiment at physiological pH is performed to…

  18. Spaceborne Sun-Induced Vegetation Fluorescence Time Series from 2007 to 2015 Evaluated with Australian Flux Tower Measurements

    NARCIS (Netherlands)

    Sanders, Abram; Verstraeten, Willem; Kooreman, Maurits; Leth, Van Thomas; Beringer, Jason; Joiner, Joanna

    2016-01-01

    A global, monthly averaged time series of Sun-induced Fluorescence (SiF), spanning January 2007 to June 2015, was derived from Metop-A Global Ozone Monitoring Experiment 2 (GOME-2) spectral measurements. Far-red SiF was retrieved using the filling-in of deep solar Fraunhofer lines and atmospheric ab

  19. Isotope shifts of natural Sr+ measured by laser fluorescence in a sympathetically cooled Coulomb crystal

    Science.gov (United States)

    Dubost, B.; Dubessy, R.; Szymanski, B.; Guibal, S.; Likforman, J.-P.; Guidoni, L.

    2014-03-01

    We measured by laser spectroscopy the isotope shifts between naturally occurring even isotopes of strontium ions for both the 5s2S1/2→5p2P1/2 (violet) and the 4d2D3/2→5p2P1/2 (infrared) dipole-allowed optical transitions. Fluorescence spectra were taken by simultaneous measurements on a two-component Coulomb crystal in a linear Paul trap containing 103-104 laser-cooled Sr+ ions. The isotope shifts are extracted from the experimental spectra by fitting the data with the analytical solution of the optical Bloch equations describing a three-level atom interacting with two laser beams. This technique allowed us to increase the precision with respect to previously reported data obtained by optogalvanic spectroscopy or fast atomic-beam techniques. The results for the 5s2S1/2→5p2P1/2 transition are ν88-ν84=+378(4) MHz and ν88-ν86=+170(3) MHz, in agreement with previously reported measurements. In the case of the previously unexplored 4d2D3/2→5p2P1/2 transition we find ν88-ν84=-828(4) MHz and ν88-ν86=-402(2) MHz. These results provide more data for stringent tests of theoretical calculations of the isotope shifts of alkali-metal-like atoms. Moreover, they simplify the identification and the addressing of Sr+ isotopes for ion frequency standards or quantum-information-processing applications in the case of multi-isotope ion strings.

  20. Thin target sup 7 Li(p, p'gamma) sup 7 Li inelastic gamma-ray yield measurements

    CERN Document Server

    Aslam; McNeill, F E

    2002-01-01

    Thin target angular distributions of inelastic gamma-ray yields resulting from sup 7 Li(p, p'gamma) sup 7 Li interaction have been measured for incident proton energies between 1.0 and 1.8 MeV. McMaster 3 MV KN Van de Graaff accelerator facility primarily dedicated to in-vivo neutron activation measurements has been used to perform experiments using a thin lithium metal target and 7.62 cm x 7.62 cm, 12.7 cm x 12.7 cm NaI(Tl) scintillation detectors and HPGe detectors. The uncertainty in the relative yield determination is based on the statistics of the data, uncertainty in the 478 keV peak area determination due to other interfering reactions, and the uncertainty in the recording of the proton charge. The results for the angular distribution provide an evidence for anisotropic nature of the radiation as compared to the presumed isotropic nature. The total relative yield was determined from the angular distributions and then compared with the published total cross sections for the reaction. Thick target yields...

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

    Science.gov (United States)

    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

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

    Directory of Open Access Journals (Sweden)

    D. A. Healy

    2014-02-01

    Full Text Available 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

  3. Measurement of the fluorescence of crop residues: A tool for controlling soil erosion

    Science.gov (United States)

    Daughtry, C. S. T.; Mcmurtrey, J. E., III; Chappelle, E. W.; Hunter, W. J.

    1994-01-01

    Management of crop residues, the portion of a crop left in the field after harvest, is an important conservation practice for minimizing soil erosion and for improving water quality. Quantification of crop residue cover is required to evaluate the effectiveness of conservation tillage practices. Methods are needed to quantify residue cover that are rapid, accurate, and objective. The fluorescence of crop residue was found to be a broadband phenomenon with emission maxima at 420 to 495 nm for excitations of 350 to 420 nm. Soils had low intensity broadband emissions over the 400 to 690 nm region for excitations of 300 to 600 nm. The range of relative fluorescence intensities for the crop residues was much greater than the fluorescence observed of the soils. As the crop residues decompose their blue fluorescence values approach the fluorescence of the soil. Fluorescence techniques are concluded to be less ambiguous and better suited for discriminating crop residues and soils than reflectance methods. If properly implemented, fluorescence techniques can be used to quantify, not only crop residue cover, but also photosynthetic efficiency in the field.

  4. A method for the measurement of in line pistachio aflatoxin concentration based on the laser induced fluorescence spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Paghaleh, Soodeh Jamali [Vali-e-Asr University of Rafsanjan, Rafsanjan (Iran, Islamic Republic of); Askari, Hassan Ranjbar; Marashi, Seyed Mohammad Bagher [Department of Physics, Faculty of Science, Vali-e-Asr University of Rafsanjan, Rafsanjan (Iran, Islamic Republic of); Rahimi, Mojtaba, E-mail: m_rahimi@vru.ac.ir [Department of Physics, Faculty of Science, Vali-e-Asr University of Rafsanjan, Rafsanjan (Iran, Islamic Republic of); Bahrampour, Ali Reza [Physics Department of Sharif University of Technology, Tehran (Iran, Islamic Republic of)

    2015-05-15

    Contamination of pistachio nuts with aflatoxin is one of the most significant issues related to pistachio health and expert. A fast pistachio aflatoxin concentration measurement method based on the laser induced fluorescence spectroscopy (LIFS) is proposed. The proposed method from theoretical and experimental points of view is analyzed. In our experiments XeCl Excimer laser is employed as an Ultra Violet (UV) source (λ=308 nm) and a UV–visible (UV–vis) spectrometer is used for fluorescent emission detection. Our setup is employed to measure the concentration of different type of Aflatoxins in pistachio nuts. Measurements results obtained by the LIFS method are compared with those are measured by the standard HPLC method. Aflatoxins concentrations are in good agreement with those are obtained by the HPLC method. The proposed laser induced fluorescence spectroscopy can be used as an in line aflatoxins concentrations measurement instrument for industrial applications. - Highlights: • XeCl Excimer laser is employed as an UV source for measurement of AFs in pistachio nuts. • Results are compared with those are measured by the standard HPLC method. • LIFS is an online AFs concentration measurement method for industrial applications.

  5. Fluorescent matter in the eastern Atlantic Ocean. Part 1: method of measurement and near-surface distribution

    Science.gov (United States)

    Determann, S.; Reuter, R.; Wagner, P.; Willkomm, R.

    1994-04-01

    Fluorescence spectra of organic matter in seawater were measured during the cruise ANT-VIII/7 of R.V. Polarsterm through the South and North Atlantic from Capetown (RSA) to Bremerhaven (Germany). The data are calibrated by normalization to the water Raman scatter band which allows their quantification without the need of fluorescence standards. Spectral structures are found which can be related to tryptophan and tyrosine-like substances, and to gelbstoff. Their distribution in the eastern Atlantic is discussed and compared with other hydrographic parameters.

  6. Elasticity Maps of Living Neurons Measured by Combined Fluorescence and Atomic Force Microscopy

    CERN Document Server

    Spedden, Elise; Naumova, Elena N; Kaplan, David L; Staii, Cristian

    2013-01-01

    Detailed knowledge of mechanical parameters such as cell elasticity, stiffness of the growth substrate, or traction stresses generated during axonal extensions is essential for understanding the mechanisms that control neuronal growth. Here we combine Atomic Force Microscopy based force spectroscopy with Fluorescence Microscopy to produce systematic, high-resolution elasticity maps for three different types of live neuronal cells: cortical (embryonic rat), embryonic chick dorsal root ganglion, and P-19 (mouse embryonic carcinoma stem cells) neurons. We measure how the stiffness of neurons changes both during neurite outgrowth and upon disruption of microtubules of the cell. We find reversible local stiffening of the cell during growth, and show that the increase in local elastic modulus is primarily due to the formation of microtubules. We also report that cortical and P-19 neurons have similar elasticity maps, with elastic moduli in the range 0.1-2 kPa, with typical average values of 0.4 kPa (P-19) and 0.2 k...

  7. A Low-Cost Fluorescent Sensor for pCO2 Measurements

    Directory of Open Access Journals (Sweden)

    Xudong Ge

    2014-04-01

    Full Text Available Global warming is believed to be caused by increasing amounts of greenhouse gases (mostly CO2 discharged into the environment by human activity. In addition to an increase in environmental temperature, an increased CO2 level has also led to ocean acidification. Ocean acidification and rising temperatures have disrupted the water’s ecological balance, killing off some plant and animal species, while encouraging the overgrowth of others. To minimize the effect of global warming on local ecosystem, there is a strong need to implement ocean observing systems to monitor the effects of anthropogenic CO2 and the impacts thereof on ocean biological productivity. Here, we describe the development of a low-cost fluorescent sensor for pCO2 measurements. The detector was exclusively assembled with low-cost optics and electronics, so that it would be affordable enough to be deployed in great numbers. The system has several novel features, such as an ideal 90° separation between excitation and emission, a beam combiner, a reference photodetector, etc. Initial tests showed that the system was stable and could achieve a high resolution despite the low cost.

  8. A simple approach for measuring FRET in fluorescent biosensors using two-photon microscopy.

    Science.gov (United States)

    Day, Richard N; Tao, Wen; Dunn, Kenneth W

    2016-11-01

    Genetically encoded fluorescent protein (FP)-based biosensor probes are useful tools for monitoring cellular events in living cells and tissues. Because these probes were developed for one-photon excitation approaches, their broad two-photon excitation (2PE) and poorly understood photobleaching characteristics have made their implementation in studies using two-photon laser-scanning microscopy (TPLSM) challenging. Here we describe a protocol that simplifies the use of Förster resonance energy transfer (FRET)-based biosensors in TPLSM. First, the TPLSM system is evaluated and optimized using FRET standards expressed in living cells, which enables the determination of spectral bleed-through (SBT) and the confirmation of FRET measurements from the known standards. Next, we describe how to apply the approach experimentally using a modified version of the A kinase activity reporter (AKAR) protein kinase A (PKA) biosensor as an example-first in cells in culture and then in hepatocytes in the liver of living mice. The microscopic imaging can be accomplished in a day in laboratories that routinely use TPLSM.

  9. Multi-confocal Fluorescence Correlation Spectroscopy : experimental demonstration and potential applications for living cell measurements

    CERN Document Server

    Galland, Rémi; Kloster, Meike; Herbomel, Gaetan; Destaing, Olivier; Balland, Martial; Souchier, Catherine; Usson, Yves; Derouard, Jacques; Wang, Irène; Delon, Antoine; 10.2741/e263

    2011-01-01

    We report, for the first time, a multi-confocal Fluorescence Correlation Spectroscopy (mFCS) technique which allows parallel measurements at different locations, by combining a Spatial Light Modulator (SLM), with an Electron Multiplying-CCD camera (EM-CCD). The SLM is used to produce a series of laser spots, while the pixels of the EM-CCD play the roles of virtual pinholes. The phase map addressed to the SLM is calculated by using the spherical wave approximation and makes it possible to produce several diffraction limited laser spots, either aligned or spread over the field of view. To attain fast enough imaging rates, the camera has been used in different acquisition modes, the fastest of which leads to a time resolution of 100 $\\mu$s. We qualified the experimental set-up by using solutions of sulforhodamine G in glycerol and demonstrated that the observation volumes are similar to that of a standard confocal set-up. To demonstrate that our mFCS method is suitable for intracellular studies, experiments have...

  10. Image processing for non-ratiometric measurement of membrane voltage using fluorescent reporters and pulsed laser illumination.

    Science.gov (United States)

    Silve, Aude; Rocke, Sarah; Frey, Wolfgang

    2015-06-01

    The measurement of transmembrane voltages induced by pulsed electric field exposure can be achieved by using fluorescent dyes like ANNINE-6. Such approach requires a quantitative determination of the fluorescence intensity along the cell's membrane by image processing. When high temporal resolution is required, the illumination source is frequently a dye-laser which causes high fluctuations in the intensity of illumination which in turn affects the fluorescence intensity and thus the quality of the results. We propose an image processing technique that allows to overcome the fluctuations and to produce quantitative data. It uses the optical background noise as a correcting factor. Standard deviation in the fluctuations is thus efficiently reduced by at least a factor of 2.5. Additionally we draw attention to the fact that the parasitic component of the laser radiation (ASE) can also suppress fluctuations although it deteriorates wavelength precision.

  11. A corrected likelihood approach for the nonlinear transformation model with application to fluorescence lifetime measurements using exponential mixtures.

    Science.gov (United States)

    Rebafka, Tabea; Roueff, François; Souloumiac, Antoine

    2010-01-01

    A fast and efficient estimation method is proposed that compensates the distortion in nonlinear transformation models. A likelihood-based estimator is developed that can be computed by an EM-type algorithm. The consistency of the estimator is shown and its limit distribution is provided. The new estimator is particularly well suited for fluorescence lifetime measurements, where only the shortest arrival time of a random number of emitted fluorescence photons can be detected and where arrival times are often modeled by a mixture of exponential distributions. The method is evaluated on real and synthetic data. Compared to currently used methods in fluorescence, the new estimator should allow a reduction of the acquisition time of an order of magnitude.

  12. Measurements of fusion neutron yields by neutron activation technique: Uncertainty due to the uncertainty on activation cross-sections

    Energy Technology Data Exchange (ETDEWEB)

    Stankunas, Gediminas, E-mail: gediminas.stankunas@lei.lt [Lithuanian Energy Institute, Laboratory of Nuclear Installation Safety, Breslaujos str. 3, LT-44403 Kaunas (Lithuania); EUROfusion Consortium, JET, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Batistoni, Paola [ENEA, Via E. Fermi, 45, 00044 Frascati, Rome (Italy); EUROfusion Consortium, JET, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Sjöstrand, Henrik; Conroy, Sean [Department of Physics and Astronomy, Uppsala University, PO Box 516, SE-75120 Uppsala (Sweden); EUROfusion Consortium, JET, Culham Science Centre, Abingdon OX14 3DB (United Kingdom)

    2015-07-11

    The neutron activation technique is routinely used in fusion experiments to measure the neutron yields. This paper investigates the uncertainty on these measurements as due to the uncertainties on dosimetry and activation reactions. For this purpose, activation cross-sections were taken from the International Reactor Dosimetry and Fusion File (IRDFF-v1.05) in 640 groups ENDF-6 format for several reactions of interest for both 2.5 and 14 MeV neutrons. Activation coefficients (reaction rates) have been calculated using the neutron flux spectra at JET vacuum vessel, both for DD and DT plasmas, calculated by MCNP in the required 640-energy group format. The related uncertainties for the JET neutron spectra are evaluated as well using the covariance data available in the library. These uncertainties are in general small, but not negligible when high accuracy is required in the determination of the fusion neutron yields.

  13. Length dependent thermal conductivity measurements yield phonon mean free path spectra in nanostructures.

    Science.gov (United States)

    Zhang, Hang; Hua, Chengyun; Ding, Ding; Minnich, Austin J

    2015-03-13

    Thermal conductivity measurements over variable lengths on nanostructures such as nanowires provide important information about the mean free paths (MFPs) of the phonons responsible for heat conduction. However, nearly all of these measurements have been interpreted using an average MFP even though phonons in many crystals possess a broad MFP spectrum. Here, we present a reconstruction method to obtain MFP spectra of nanostructures from variable-length thermal conductivity measurements. Using this method, we investigate recently reported length-dependent thermal conductivity measurements on SiGe alloy nanowires and suspended graphene ribbons. We find that the recent measurements on graphene imply that 70% of the heat in graphene is carried by phonons with MFPs longer than 1 micron.

  14. In Situ Airborne Measurement of Formaldehyde with a New Laser Induced Fluorescence Instrument

    Science.gov (United States)

    Arkinson, H.; Hanisco, T. F.; Cazorla, M.; Fried, A.; Walega, J.

    2012-12-01

    Formaldehyde (HCHO) is a highly reactive and ubiquitous compound in the atmosphere that originates from primary emissions and secondary formation by photochemical oxidation of volatile organic compounds. HCHO is an important precursor to the formation of ozone and an ideal tracer for the transport of boundary layer pollutants to higher altitudes. In situ measurements of HCHO are needed to improve understanding of convective transport mechanisms and the effects of lofted pollutants on ozone production and cloud microphysics in the upper troposphere. The Deep Convective Clouds and Chemistry Project (DC3) field campaign addressed the effects of deep, midlatitude continental convective clouds on the upper troposphere by examining vertical transport of fresh emissions and water aloft and by characterizing subsequent changes in composition and chemistry. Observations targeting convective storms were conducted over Colorado, Alabama, and Texas and Oklahoma. We present measurements of the In Situ Airborne Formaldehyde instrument (ISAF), which uses laser induced fluorescence to achieve the high sensitivity and fast time response required to detect low concentrations in the upper troposphere and capture the fine structure characteristic of convective storm outflow. Preliminary results from DC3 indicate that the ISAF is able to resolve concentrations ranging from under 35 ppt to over 35 ppb, spanning three orders of magnitude, in less than a few minutes. Frequent, abrupt changes in HCHO captured by the ISAF are corroborated by similar patterns observed by simultaneous trace gas and aerosol measurements. Primary HCHO emissions are apparent in cases when the DC-8 flew over combustion sources or biomass burning, and secondary HCHO formation is suggested by observations of enhanced HCHO concurrent with other elevated hydrocarbons. Vertical transport of HCHO is indicated by measurements of over 6 ppb from outflow in the upper troposphere. The DC-8 payload also included the

  15. Measuring transverse spin correlations by 4-particle correlations in e{sup +}e{sup -} {yields} 2 jets

    Energy Technology Data Exchange (ETDEWEB)

    Artu, X. [Lyon-1 Univ., 69 - Villeurbanne (France). Inst. de Physique Nucleaire; Collins, J. [Pennsylvania State Univ., University Park, PA (United States). Davey Lab.

    1996-01-01

    The azimuthal distribution of pairs of particles in a jet is sensitive to the transverse polarization of the quark initiating the jet, but with a sensitivity that involves a nonperturbative analyzing power. We show in detail how to measure the analyzing power from 4-hadron correlations in e{sup +}e{sup -} {yields} 2 jets. We explain the combinations of particle flavor that are likely to give the biggest effect. (orig.)

  16. An automated and highly efficient method for counting and measuring fluorescent foci in rod-shaped bacteria

    DEFF Research Database (Denmark)

    Nielsen, Henrik Jørck; Hansen, Flemming G.

    2010-01-01

    P>Direct measurements of cells from photo micrographs are becoming increasingly used when investigating the position and/or distribution of chromosomal loci in bacteria. In general, these measurements have been done manually, and without clear definition of how they are made. Here we present...... a procedure for standardizing the measurement of cell properties from phase contrast images. Furthermore, we present a program using these standardized methods that can measure the intracellular positions of fluorescent foci in bacterial cells faster and with more precision than manual measurement....

  17. Particle-fluorescence spectrometer for real-time single-particle measurements of atmospheric organic carbon and biological aerosol.

    Science.gov (United States)

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

    2009-01-15

    A particle-fluorescence spectrometer (PFS) for real-time measurements of single-particle UV-laser-induced fluorescence (UV-LIF) excited with a pulsed (263-nm) laser is reported. The dispersed UV-LIF spectra are measured by a 32-anode PMT detector with spectral coverage from 280-600 nm. The PFS represents a significant improvement over our previous apparatus [Pinnick et al., Atmos. Environ. 2004, 38, 1657] and can (1) measure fluorescence spectra of bacterial particles having light-scattering sizes as small as 1 microm (previously limited to about 3 microm) and so can measure particles with size in the range of 1-10 microm, (2) measure each particle's elastic scattering which can be used to estimate particle size (not available previously), (3) measure single-particle fluorescence spectra with a laser and detector that can record spectra as fast as 90,000/s, although the highest rates we have found experimentally in atmospheric measurements is only several hundred per second (previously limited by detectors to only 25/s), and (4) provide a time stamp for a data block of spectra with time resolution from 10 ms to 10 min. In addition, the PFS has been modified to be more robust, transportable, and smaller. The use of an aerodynamic-focusing sheath inlet nozzle assembly has improved the sample rate. The PFS has been employed to measure UV-LIF spectra from individual atmospheric particles during October-December 2006 and January-May 2008 in New Haven, CT, and during January-May 2007 in Las Cruces, NM.

  18. Genetic parameters of different measures of cheese yield and milk nutrient recovery from an individual model cheese-manufacturing process.

    Science.gov (United States)

    Bittante, G; Cipolat-Gotet, C; Cecchinato, A

    2013-01-01

    Cheese yield (CY) is an important technological trait in the dairy industry, and the objective of this study was to estimate the genetic parameters of cheese yield in a dairy cattle population using an individual model-cheese production procedure. A total of 1,167 Brown Swiss cows belonging to 85 herds were sampled once (a maximum of 15 cows were sampled per herd on a single test day, 1 or 2 herds per week). From each cow, 1,500 mL of milk was processed according to the following steps: milk sampling and heating, culture addition, rennet addition, gelation-time recording, curd cutting, whey draining and sampling, wheel formation, pressing, salting in brine, weighing, and cheese sampling. The compositions of individual milk, whey, and curd samples were determined. Three measures of percentage cheese yield (%CY) were calculated: %CY(CURD), %CY(SOLIDS), and %CY(WATER), which represented the ratios between the weight of fresh curd, the total solids of the curd, and the water content of the curd, respectively, and the weight of the milk processed. In addition, 3 measures of daily cheese yield (dCY, kg/d) were defined, considering the daily milk yield. Three measures of nutrient recovery (REC) were computed: REC(FAT), REC(PROTEIN), and REC(SOLIDS), which represented the ratio between the weights of the fat, protein, and total solids in the curd, respectively, and the corresponding nutrient in the milk. Energy recovery, REC(ENERGY), represented the energy content of the cheese versus that in the milk. For statistical analysis, a Bayesian animal model was implemented via Gibbs sampling. The effects of parity (1 to ≥4), days in milk (6 classes), and laboratory vat (15 vats) were assigned flat priors; those of herd-test-date, animal, and residual were given Gaussian prior distributions. Intra-herd heritability estimates of %CY(CURD), %CY(SOLIDS), and %CY(WATER) ranged from 0.224 to 0.267; these were larger than the estimates obtained for milk yield (0.182) and milk fat

  19. A Modified activation method for reaction total cross section and yield measurements at low astrophysically relevant energies

    Energy Technology Data Exchange (ETDEWEB)

    Artemov, S.V., E-mail: artemov@inp.uz [Institute of Nuclear Physics of Uzbekistan Academy of Sciences, Tashkent (Uzbekistan); Igamov, S.B.; Karakhodjaev, A.A.; Radyuk, G.A.; Tojiboyev, O.R.; Salikhbaev, U.S.; Ergashev, F.Kh.; Nam, I.V. [Institute of Nuclear Physics of Uzbekistan Academy of Sciences, Tashkent (Uzbekistan); Aliev, M.K.; Kholbaev, I.; Rumi, R.F.; Khalikov, R.I.; Eshkobilov, Sh.Kh.; Muminov, T.M. [Research Institute of Applied Physics, National University of Uzbekistan, Tashkent (Uzbekistan)

    2016-07-21

    The activation method is proposed for collection of the sufficient statistics during the investigation of the nuclear astrophysical reactions at low energies with the short-living residual nuclei formation. The main feature is a multiple cyclical irradiation of a target by an ion beam and measurement of the radioactivity decay curve. The method was tested by the yield measurement of the {sup 12}C(p,γ){sup 13}N reaction with detecting the annihilation γγ- coincidences from {sup 13}N(β{sup +}ν){sup 13}C decay at the two-arm scintillation spectrometer.

  20. Recognition memory measures yield disproportionate effects of aging on learning face-name associations.

    Science.gov (United States)

    James, Lori E; Fogler, Kethera A; Tauber, Sarah K

    2008-09-01

    No previous research has tested whether the specific age-related deficit in learning face-name associations that has been identified using recall tasks also occurs for recognition memory measures. Young and older participants saw pictures of unfamiliar people with a name and an occupation for each person, and were tested on a matching (in Experiment 1) or multiple-choice (in Experiment 2) recognition memory test. For both recognition measures, the pattern of effects was the same as that obtained using a recall measure: More face-occupation associations were remembered than face-name associations, young adults remembered more associated information than older adults overall, and older adults had disproportionately poorer memory for face-name associations. Findings implicate age-related difficulty in forming and retrieving the association between the face and the name as the primary cause of obtained deficits in previous name learning studies. (c) 2008 APA, all rights reserved

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

    Science.gov (United States)

    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.

  2. Multiple effects of cadmium on the photosynthetic apparatus of Avicennia germinans L. as probed by OJIP chlorophyll fluorescence measurements

    Energy Technology Data Exchange (ETDEWEB)

    Gonzales-Mendoza, D.; Zapata-Perez, O. [Cinvestav Unidad Merida, Yucatan (Mexico). Dept. de Recursos del Mar; Espadas y Gil, F.; Santamaria, J.M. [Unidad de Biotecnologia, CICY, Yucatan (Mexico)

    2007-03-15

    The toxic effects of cadmium on the photosynthetic apparatus of Avicennia germinans were evaluated by means of the chlorophyll fluorescence transient O-J-I-P. The chlorophyll fluorescence transients were recorded in vivo with high time resolution and analyzed according to the OJIP-test that can quantify the performance of photosystem II. Cadmium-treated plants showed a decrease in yield for primary photochemistry, TR{sup 0}/ABS. The performance index of photosystem II (PSII), PI{sub ABS}, decreased due to cadmium treatment. This performance index is the combination of the indexes of three independent parameters: (1) total number of active reaction centers per absorption (RC/ABS), (2) yield of primary photochemistry (TR{sup 0}/ABS), and (3) efficiency with which a trapped exciton can move an electron into the electron transport chain (ET{sup 0}/TR{sup 0}). Additionally, the F{sub 0}/F{sub v} registered the highest sensitivity to the metal, thus indicating that the water-splitting apparatus of the oxidizing side of PSII is the primary site of action of cadmium. In summary, cadmium affects several targets of photosystem II. More specifically the main targets of cadmium, according to the OJIP-test, can be listed as a decrease in the number of active reaction centers and damage to the activity of the water-splitting complex. (orig.)

  3. Mechanisms of ultrafast fluorescence depletion spectroscopy and applications to measure slovation dynamics of coummarin 153 in methanol

    Energy Technology Data Exchange (ETDEWEB)

    Yang Songqiu, E-mail: sqyang@dicp.ac.cn [State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100039 (China); Liu Jianyong, E-mail: beam@dicp.ac.cn [State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 (China); Zhou Panwang, E-mail: pwzhou@dicp.ac.cn [State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 (China); Chen Junsheng, E-mail: junshengchen@dicp.ac.cn [State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100039 (China); Han Keli, E-mail: klhan@dicp.ac.cn [State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 (China); He Guozhong, E-mail: gzhe@dicp.ac.cn [State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 (China)

    2012-09-15

    Subpicosecond fluorescence depletion spectroscopy (FDS) was used to measure the solvation dynamics of coumarin 153 (C153) in methanol. The FDS mechanisms were discussed. A quasi-continuous model was used to describe the solvational relaxation of excited states. The perturbations of the probe pulse on the excited sample system, including up-conversion and stimulated emission, were sufficiently discussed. For a probe molecule used in the FDS experiment, ensuring that the up-conversion perturbation can be negligible is important. FDS was found to be a good technique for measuring the solvation dynamics of C153 in methanol. - Highlights: Black-Right-Pointing-Pointer Mechanisms of subpicosecond fluorescence depletion spectroscopy. Black-Right-Pointing-Pointer Quasi-continuous model was used to describe the solvational relaxation. Black-Right-Pointing-Pointer The solvation dynamics of coumarin 153 in methanol has been measured.

  4. Cultural control measures to diminish sorghum yield loss and parasite success under Striga hermonthica infestation

    NARCIS (Netherlands)

    Ast, van A.; Bastiaans, L.; Katile, S.

    2005-01-01

    Prospects of reducing Striga hermonthica (Del.) Benth. parasitism by means of cultural control measures were assessed. In a pot experiment, deep planting, the use of transplants and shallow soil-tillage, strongly delayed and reduced Striga infection of a sensitive and a tolerant sorghum cultivar.

  5. Effects of amiodarone therapy on thyroid iodine content as measured by x-ray fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Fragu, P.; Schlumberger, M.; Davy, J.M.; Slama, M.; Berdeaux, A.

    1988-04-01

    Thyroid iodine content (TIC) was measured by x-ray fluorescence in 68 patients who had received amiodarone treatment for varying intervals (1 g/week for 1-120 months). Thirty-six patients were euthyroid; the mean TIC of the patients (n = 15), who had been treated for less than 12 months was 30 +/- 19 (+/- SD) mg, twice the normal mean value (14.6 +/- 5.0 mg), and it was 39 +/- 17 mg in those (n = 16) who had been treated for 12-60 months and 29 +/- 6 mg in those (n = 5) who had been treated longer (greater than 60 months). Nineteen patients were hyperthyroid and had elevated TIC values. Of them, 6 patients had a goiter; their TIC (50 +/- 19 mg) was not significantly different from that of the hyperthyroid patients with no goiter (55 +/- 29 mg), but they became hyperthyroid more rapidly. Thirteen patients were hypothyroid; none had TIC values above the normal range, and it was below 2.5 mg in 5 patients. A sequential study was undertaken in 11 euthyroid patients who had no detectable antithyroid antibodies. TIC did not increase during treatment in 2 patients; both developed hypothyroidism, which was transient in 1 despite continuation of amiodarone treatment. The TIC initially increased during amiodarone treatment in the other 9 patients, leveling off at the end of the first year. The TIC rose well above the upper limit of the normal range in 4 patients, of whom 2 became hyperthyroid during the second year of treatment. TIC remained within the normal range in the other 5 patients, of whom 3 became hypothyroid after 12-24 months of treatment (1 subclinical, 2 overt). Although the TIC was significantly higher in the patients with hyperthyroidism than in the patients who remained euthyroid, the TIC test cannot be used to predict the occurrence of hyperthyroidism.

  6. Healthy Dietary Patterns and Oxidative Stress as Measured by Fluorescent Oxidation Products in Nurses’ Health Study

    Directory of Open Access Journals (Sweden)

    Seungyoun Jung

    2016-09-01

    Full Text Available Healthy diets may lower oxidative stress and risk of chronic diseases. However, no previous studies examined associations between diet and fluorescent oxidation products (FlOP, a global marker of oxidative stress. We evaluated associations between healthy eating patterns (Alternative Healthy Eating Index (AHEI, Dietary Approach to Stop Hypertension (DASH, and Alternate Mediterranean Diet (aMED and FlOP, measured at three excitation/emission wavelengths (FlOP_360, FlOP_320, FlOP_400 from 2021 blood samples collected from 1688 women within the Nurses’ Health Study. AHEI, DASH, and aMED scores were significantly positively associated with FlOP_360 and FlOP_320 concentrations (p-trend ≤ 0.04, but not associated with FlOP_400. Among specific food groups that contribute to these diet scores, significantly positive associations were observed with legumes and vegetables for FlOP_360, vegetables and fruits for FlOP_320, and legumes and alcohol for FlOP_400. Inverse associations were observed with nuts, sweets or desserts, and olive oil for FlOP_360, nuts for FlOP_320 and sweets or desserts for FlOP_400 (all p-trend ≤ 0.05. However, FlOP variation due to diet was small compared to overall FlOP variation. In conclusion, AHEI, DASH, and aMED scores were unexpectedly positively, but weakly, associated with FlOP_360 and FlOP_320. However, these findings should be interpreted cautiously as the determinants of FlOP concentrations are not fully understood.

  7. Interannual Variability in Dry Mixed-Grass Prairie Yield: A Comparison of MODIS, SPOT, and Field Measurements

    Directory of Open Access Journals (Sweden)

    Donald C. Wehlage

    2016-10-01

    Full Text Available Remote sensing is often used to assess rangeland condition and biophysical parameters across large areas. In particular, the relationship between the Normalized Difference Vegetation Index (NDVI and above-ground biomass can be used to assess rangeland primary productivity (seasonal carbon gain or above-ground biomass “yield”. We evaluated the NDVI–yield relationship for a southern Alberta prairie rangeland, using seasonal trends in NDVI and biomass during the 2009 and 2010 growing seasons, two years with contrasting rainfall regimes. The study compared harvested biomass and NDVI from field spectrometry to NDVI from three satellite platforms: the Aqua and Terra Moderate Resolution Imaging Spectroradiometer (MODIS and Système Pour l’Observation de la Terre (SPOT 4 and 5. Correlations between ground spectrometry and harvested biomass were also examined for each growing season. The contrasting precipitation patterns were easily captured with satellite NDVI, field NDVI and green biomass measurements. NDVI provided a proxy measure for green plant biomass, and was linearly related to the log of standing green biomass. NDVI phenology clearly detected the green biomass increase at the beginning of each growing season and the subsequent decrease in green biomass at the end of each growing season due to senescence. NDVI–biomass regressions evolved over each growing season due to end-of-season senescence and carryover of dead biomass to the following year. Consequently, mid-summer measurements yielded the strongest correlation (R2 = 0.97 between NDVI and green biomass, particularly when the data were spatially aggregated to better match the satellite sampling scale. Of the three satellite platforms (MODIS Aqua, MODIS Terra, and SPOT, Terra yielded the best agreement with ground-measured NDVI, and SPOT yielded the weakest relationship. When used properly, NDVI from satellite remote sensing can accurately estimate peak-season productivity and

  8. Assessment of crop yield losses in Punjab and Haryana using two years of continuous in-situ ozone measurements

    Science.gov (United States)

    Sinha, B.; Singh Sangwan, K.; Maurya, Y.; Kumar, V.; Sarkar, C.; Chandra, B. P.; Sinha, V.

    2015-01-01

    In this study we use a high quality dataset of in-situ ozone measurements at a suburban site called Mohali in the state of Punjab to estimate ozone related crop yield losses for wheat, rice, cotton and maize for Punjab and the neighbouring state Haryana for the years 2011-2013. We inter-compare crop yield loss estimates according to different exposure metrics such as AOT40 and M7 for the two major crop growing seasons of Kharif (June-October) and Rabi (November-April) and establish a new crop yield exposure relationship for South Asian wheat and rice cultivars. These are a factor of two more sensitive to ozone induced crop yield losses compared to their European and American counterparts. Relative yield losses based on the AOT40 metrics ranged from 27-41% for wheat, 21-26% for rice, 9-11% for maize and 47-58% for cotton. Crop production losses for wheat amounted to 20.8 million t in fiscal year 2012-2013 and 10.3 million t in fiscal year 2013-2014 for Punjab and Haryana jointly. Crop production losses for rice totalled 5.4 million t in fiscal year 2012-2013 and 3.2 million t year 2013-2014 for Punjab and Haryana jointly. The Indian National Food Security Ordinance entitles ~ 820 million of India's poor to purchase about 60 kg of rice/wheat per person annually at subsidized rates. The scheme requires 27.6 Mt of wheat and 33.6 Mt of rice per year. Mitigation of ozone related crop production losses in Punjab and Haryana alone could provide >50% of the wheat and ~10% of the rice required for the scheme. The total economic cost losses in Punjab and Haryana amounted to USD 6.5 billion in the fiscal year 2012-2013 and USD 3.7 billion in the fiscal year 2013-2014. This economic loss estimate represents a very conservative lower limit based on the minimum support price of the crop, which is lower than the actual production costs. The upper limit for ozone related crop yield losses in entire India currently amounts to 3.5-20% of India's GDP. Mitigation of high surface ozone

  9. Effect of uncertainty in composition and weight measures in control of cheese yield and fat loss in large cheese factories.

    Science.gov (United States)

    Margolies, Brenda; Adams, Michael C; Pranata, Joice; Gondoutomo, Kathleen; Barbano, David M

    2017-08-01

    Our objective was to develop a computer-based cheese yield, fat recovery, and composition control performance measurement system to provide quantitative performance records for a Cheddar and mozzarella cheese factory. The system can be used to track trends in performance of starter cultures and vats, as well as systematically calculate theoretical yield. Yield equations were built into the spreadsheet to evaluate cheese yield performance and fat losses in a cheese factory. Based on observations in commercial cheese factories, sensitivity analysis was done to demonstrate the sensitivity of cheese factory performance to analytical uncertainty of data used in the evaluation. Analytical uncertainty in the accuracy of milk weight and milk and cheese composition were identified as important factors that influence the ability to manage consistency of cheese quality and profitability. It was demonstrated that an uncertainty of ±0.1% milk fat or milk protein in the vat causes a range of theoretical Cheddar cheese yield from 10.05 to 10.37% and an uncertainty of yield efficiency of ±1.5%. This equates to ±1,451 kg (3,199 lb) of cheese per day in a factory processing 907,185 kg (2 million pounds) of milk per day. The same is true for uncertainty in cheese composition, where the effect of being 0.5% low on moisture or fat is about 484 kg (1,067 lb) of missed revenue opportunity from cheese for the day. Missing the moisture target causes other targets such as fat on a dry basis and salt in moisture to be missed. Similar impacts were demonstrated for mozzarella cheese. In analytical performance evaluations of commercial cheese quality assurance laboratories, we found that analytical uncertainty was typically a bias that was as large as 0.5% on fat and moisture. The effect of having a high bias of 0.5% moisture or fat will produce a missed opportunity of 484 kg of cheese per day for each component. More accurate rapid methods for determination of moisture, fat, and salt

  10. Measurement of the effective B{sub s}{sup 0}{yields}K{sup +}K{sup -} lifetime

    Energy Technology Data Exchange (ETDEWEB)

    Aaij, R. [Nikhef National Institute for Subatomic Physics, Amsterdam (Netherlands); Abellan Beteta, C. [Universitat de Barcelona, Barcelona (Spain); Adametz, A. [Physikalisches Institut, Ruprecht-Karls-Universitaet Heidelberg, Heidelberg (Germany); Adeva, B. [Universidad de Santiago de Compostela, Santiago de Compostela (Spain); Adinolfi, M. [H.H. Wills Physics Laboratory, University of Bristol, Bristol (United Kingdom); Adrover, C. [CPPM, Aix-Marseille Universite, CNRS/IN2P3, Marseille (France); Affolder, A. [Oliver Lodge Laboratory, University of Liverpool, Liverpool (United Kingdom); Ajaltouni, Z. [Clermont Universite, Universite Blaise Pascal, CNRS/IN2P3, LPC, Clermont-Ferrand (France); Albrecht, J.; Alessio, F. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Alexander, M. [School of Physics and Astronomy, University of Glasgow, Glasgow (United Kingdom); Ali, S. [Nikhef National Institute for Subatomic Physics, Amsterdam (Netherlands); Alkhazov, G. [Petersburg Nuclear Physics Institute (PNPI), Gatchina (Russian Federation); Alvarez Cartelle, P. [Universidad de Santiago de Compostela, Santiago de Compostela (Spain); Alves, A.A. [Sezione INFN di Roma La Sapienza, Roma (Italy); Amato, S. [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro (Brazil); Amhis, Y. [Ecole Polytechnique Federale de Lausanne (EPFL), Lausanne (Switzerland); Anderson, J. [Physik-Institut, Universitaet Zuerich, Zuerich (Switzerland); Appleby, R.B. [School of Physics and Astronomy, University of Manchester, Manchester (United Kingdom); Aquines Gutierrez, O. [Max-Planck-Institut fuer Kernphysik (MPIK), Heidelberg (Germany); and others

    2012-10-02

    A precise determination of the effective B{sub s}{sup 0}{yields}K{sup +}K{sup -} lifetime can be used to constrain contributions from physics beyond the Standard Model in the B{sub s}{sup 0} meson system. Conventional approaches select B meson decay products that are significantly displaced from the B meson production vertex. As a consequence, B mesons with low decay times are suppressed, introducing a bias to the decay time spectrum which must be corrected. This analysis uses a technique that explicitly avoids a lifetime bias by using a neural network based trigger and event selection. Using 1.0 fb{sup -1} of data recorded by the LHCb experiment, the effective B{sub s}{sup 0}{yields}K{sup +}K{sup -} lifetime is measured as 1.455{+-}0.046(stat.){+-}0.006(syst.)ps.

  11. Thick Target Yield Measurement for PAC Probe Producing Reaction Mo (19F, xn)111In

    Institute of Scientific and Technical Information of China (English)

    ZHENGYong-nan; ZHOUDong-mei; DUEn-peng; YUANDa-qing; ZUOYi; CHENXiong-jun; WUXiao-guang; CUIBao-qun; ZHUSheng-yun

    2003-01-01

    Perturbed angular correlation (PAC) directly determines the hyperfine interaction acting on the PAC probe nuclei, which is a sensitive and precise method for microscopic analysis on an atomic scale, 111Cd is the most frequently used PAC probe nuclei, the mother nuclei of which is 111In. The on-line isotope separator (ISOL) based on the HI-13 tandem accelerator is being developed at China Institute of Atomic Energy, which produces the radioactive nuclear beams for the on-line PAC measurements.

  12. Design of an electronic charged particle spectrometer to measure ({rho}R), yield, and implosion symmetry on the OMEGA Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Hicks, D.G.; Li, C.K.; Petrasso, R.D.; Wenzel, K.W. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Plasma Fusion Center; Knauer, J.P. [Rochester Univ., NY (United States). Lab. for Laser Energetics

    1994-11-01

    The preliminary design for a state-of-the-art diagnostic that will measure a broad energy spectrum of charged particles generated in the OMEGA Upgrade facility is investigated. Using a set of photodiodes ({approximately}10) and a 0.8 Tesla permanent magnet, the diagnostic will uniquely determine particle energies and identities from 0.2 MeV up to the maximum charged particle energies (10.6 MeV tritons, 12.5 MeV deuterons and 17.4 MeV protons). With its high density picture elements, each photodiode has 10{sup 6} single-hit detectors, giving the spectrometer a dynamic range of 1 {minus} 10{sup 5} particles/shot. For example, in the case of a DT yield of 10{sup 9} neutrons, about 100 knock-on charged particles will be detected when the spectrometer aperture is 60 cm from the implosion. Furthermore, the measurement of knock-on D and T spectra will allow {rho}R`s up to 0.15 g/cm{sup 2} to be measured (for a 1 keV plasma), or 0.3 g/cm{sup 2}2 if hydrogen doping is used. In addition, the yield and slowing down of secondary protons may be used to determine {rho}R up to 0.3 g/cm{sup 2}. Significantly, this diagnostic will also directly measure the DD fusion yield and energy degradation of nascent 3 MeV protons. By using two such compact spectrometers to measure the yield and spectra on widely separated ports around the OMEGA Upgrade target chamber, the implosion and bum symmetry can be determined. Furthermore, the ion temperature, and, in principle, even the electron temperature can be measured. The diagnostic and its development will be fully tested at several critical steps, utilizing 0.2-16 MeV protons (and several other charged particles and neutrons) from our absolutely calibrated Cockcroft-Walton facility.

  13. Measurements of actinide-fission product yields in Caliban and Prospero metallic core reactor fission neutron fields

    Energy Technology Data Exchange (ETDEWEB)

    Casoli, P.; Authier, N. [CEA, Centre de Valduc, 21120 Is-sur-Tille (France); Laurec, J.; Bauge, E.; Granier, T. [CEA, Centre DIF, 91297 Arpajon (France)

    2011-07-01

    In the 1970's and early 1980's, an experimental program was performed on the facilities of the CEA Valduc Research Center to measure several actinide-fission product yields. Experiments were, in particular, completed on the Caliban and Prospero metallic core reactors to study fission-neutron-induced reactions on {sup 233}U, {sup 235}U, and {sup 239}Pu. Thick actinide samples were irradiated and the number of nuclei of each fission product was determined by gamma spectrometry. Fission chambers were irradiated simultaneously to measure the numbers of fissions in thin deposits of the same actinides. The masses of the thick samples and the thin deposits were determined by mass spectrometry and alpha spectrometry. The results of these experiments will be fully presented in this paper for the first time. A description of the Caliban and Prospero reactors, their characteristics and performances, and explanations about the experimental approach will also be given in the article. A recent work has been completed to analyze and reinterpret these measurements and particularly to evaluate the associated uncertainties. In this context, calculations have also been carried out with the Monte Carlo transport code Tripoli-4, using the published benchmarked Caliban description and a three-dimensional model of Prospero, to determine the average neutron energy causing fission. Simulation results will be discussed in this paper. Finally, new fission yield measurements will be proposed on Caliban and Prospero reactors to strengthen the results of the first experiments. (authors)

  14. HARP targets pion production cross section and yield measurements. Implications for MiniBooNE neutrino flux

    Energy Technology Data Exchange (ETDEWEB)

    Wickremasinghe, Don Athula Abeyarathna [Univ. of Cincinnati, OH (United States)

    2015-07-01

    The prediction of the muon neutrino flux from a 71.0 cm long beryllium target for the MiniBooNE experiment is based on a measured pion production cross section which was taken from a short beryllium target (2.0 cm thick - 5% nuclear interaction length) in the Hadron Production (HARP) experiment at CERN. To verify the extrapolation to our longer target, HARP also measured the pion production from 20.0 cm and 40.0 cm beryllium targets. The measured production yields, d2Nπ± (p; θ )=dpd Ω, on targets of 50% and 100% nuclear interaction lengths in the kinematic rage of momentum from 0.75 GeV/c to 6.5 GeV/c and the range of angle from 30 mrad to 210 mrad are presented along with an update of the short target cross sections. The best fitted extended Sanford-Wang (SW) model parameterization for updated short beryllium target π+ production cross section is presented. Yield measurements for all three targets are also compared with that from the Monte Carlo predictions in the MiniBooNE experiment for different SW parameterization. The comparisons of vμ flux predictions for updated SW model is presented.

  15. Estimation of Corn Yield and Soil Nitrogen via Soil Electrical Conductivity Measurement Treated with Organic, Chemical and Biological Fertilizers

    Directory of Open Access Journals (Sweden)

    H. Khalilzade

    2016-02-01

    Full Text Available Introduction Around the world maize is the second crop with the most cultivated areas and amount of production, so as the most important strategic crop, have a special situation in policies, decision making, resources and inputs allocation. On the other side, negative environmental consequences of intensive consumption of agrochemicals resulted to change view concerning food production. One of the most important visions is sustainable production of enough food plus attention to social, economic and environmental aspects. Many researchers stated that the first step to achieve this goal is optimization and improvement of resources use efficiencies. According to little knowledge on relation between soil electrical conductivity and yield of maize, beside the environmental concerns about nitrogen consumption and need to replace chemical nitrogen by ecological inputs, this study designed and aimed to evaluate agroecological characteristics of corn and some soil characteristics as affected by application of organic and biological fertilizers under field conditions. Materials and Methods In order to probing the possibility of grain yield and soil nitrogen estimation via measurement of soil properties, a field experiment was conducted during growing season 2010 at Research Station, Ferdowsi University of Mashhad, Iran. A randomized complete block design (RCBD with three replications was used. Treatments included: 1- manure (30 ton ha-1, 2-vermicompost (10 ton ha-1, 3- nitroxin (containing Azotobacter sp. and Azospirillum sp., inoculation was done according to Kennedy et al., 4- nitrogen as urea (400 kg ha-1 and 5- control (without fertilizer. Studied traits were soil pH, soil EC, soil respiration rate, N content of soil and maize yield. Soil respiration rate was measured using equation 1: CO2= (V0- V× N×22 Equation 1 In which V0 is the volume of consumed acid for control treatment titration, V is of the volume of consumed acid for sample treatment

  16. Element distribution in the brain sections of rats measured by synchrotron radiation X-ray fluorescence

    Science.gov (United States)

    Liu, N. Q.; Zhang, F.; Wang, X. F.; Zhang, Z. Y.; Chai, Z. F.; Huang, Y. Y.; He, W.; Zhao, X. Q.; Zuo, A. J.; Yang, R.

    2004-02-01

    The concentration of trace elements in brain sections was measured by synchrotron radiation X-ray fluorescence. The relative concentration was calculated by means of the normalization of Compton scattering intensity approximately 22 keV, after the normalization for collecting time of X-ray spectrum and the counting of the ion chamber, and subtracting the contribution of the polycarbonate film for supporting sample. Furthermore, the statistical evaluation of the element distribution in various regions of the brain sections of the 20-day-old rats was tested. For investigating the distribution of elements in the brain of iodine deficient rats, Wistar rats were fed with iodine deficient diet and deionized water (ID group). The rats were fed the same iodine deficient diet, but drank KIO 3 solution as control (CT group). The results showed that the contents of calcium (Ca) in thalamus (TH) and copper (Cu) and iron (Fe) in cerebral cortex (CX) of ID rats were significantly lower than that of control rats, while the contents of phosphor (P), sulfur (S), potassium (K), rubidium (Rb), bromine (Br), chlorine (Cl), zinc (Zn), Ca and Cu of ID in hippocampus (H) and the contents of Br, Cl, Zn and Ca in cerebral cortex of ID rats were significantly higher. Especially, the difference of Br, Cl, Zn and Ca in H between ID and CT was more significant. The contents of all elements measured in H were higher than (or equal to) CX and/or TH for both groups, except low Cl of the control rats. Furthermore Zn and Cu contents along the hippocampal fissure in both groups were 1.5 ( Ptimes higher than in hippocampus, respectively. Considering the results of cluster analysis our study shows that the marked alterations in the spatial distribution of Zn and Ca of ID rats brain during brain development stages. In addition, the effect of the perfusion with 0.9% NaCl solution before taking brain on the distribution of elements in the brain sections was observed and discussed.

  17. Uncertainty calculations for the measurement of in vivo bone lead by x-ray fluorescence.

    Science.gov (United States)

    O'Meara, J M; Fleming, D E B

    2009-04-21

    In order to quantify the bone lead concentration from an in vivo x-ray fluorescence measurement, typically two estimates of the lead concentration are determined by comparing the normalized x-ray peak amplitudes from the Kalpha(1) and Kbeta(1) features to those of the calibration phantoms. In each case, the normalization consists of taking the ratio of the x-ray peak amplitude to the amplitude of the coherently scattered photon peak in the spectrum. These two Pb concentration estimates are then used to determine the weighted mean lead concentration of that sample. In calculating the uncertainties of these measurements, it is important to include any covariance terms where appropriate. When determining the uncertainty of the lead concentrations from each x-ray peak, the standard approach does not include covariance between the x-ray peaks and the coherently scattered feature. These spectral features originate from two distinct physical processes, and therefore no covariance between these features can exist. Through experimental and simulated data, we confirm that there is no observed covariance between the detected Pb x-ray peaks and the coherently scattered photon signal, as expected. This is in direct contrast to recent work published by Brito (2006 Phys. Med. Biol. 51 6125-39). There is, however, covariance introduced in the calculation of the weighted mean lead concentration due to the common coherent normalization. This must be accounted for in calculating the uncertainty of the weighted mean lead concentration, as is currently the case. We propose here an alternative approach to calculating the weighted mean lead concentration in such a way as to eliminate the covariance introduced by the common coherent normalization. It should be emphasized that this alternative approach will only apply in situations in which the calibration line intercept is not included in the calculation of the Pb concentration from the spectral data: when the source of the intercept is

  18. Histologic differences between orthotopic xenograft pancreas models affect Verteporfin uptake measured by fluorescence microscopy and spectroscopy

    Science.gov (United States)

    O'Hara, Julia A.; Samkoe, Kimberley S.; Chen, Alina; Isabelle, Martin; Hoopes, P. J.; Hasan, Tayyaba; Pogue, Brian W.

    2012-02-01

    Photodynamic therapy (PDT) that uses the second generation photosensitizer, verteporfin (VP), is a developing therapy for pancreatic cancer. The optimal timing of light delivery related to VP uptake and distribution in pancreatic tumors will be important information to obtain to improve treatment for this intractable disease. In this work we examined uptake and distribution of VP in two orthotopic pancreatic tumors with different histological structure. ASPC-1 (fast-growing) and Panc-1 (slower growing) tumors were implanted in SCID mice and studied when tumors were approximately 100mm3. In a pilot study, these tumors had been shown to differ in uptake of VP using lightinduced fluorescence spectroscopy (LIFS) in vivo and fluorescence imaging ex vivo and that work is extended here. In vivo fluorescence mean readings of tumor and liver increased rapidly up to 15 minutes after photosensitizer injection for both tumor types, and then continued to increase up to 60 minutes post injection to a higher level in ASPC-1 than in Panc-1. There was variability among animals with the same tumor type, in both liver and tumor uptake and no selectivity of tumor over liver. In this work we further examined VP uptake at multiple time points in relation to microvascular density and perfusion, using DiOC7 (to mark blood vessels) and VP fluorescence in the same tissue slices. Analysis of DiOC7 fluorescence indicates that AsPC-1 and Panc-1 have different vascular densities but AsPC-1 vasculature is more perfusive. Analysis of colocalized DiOC7 and VP fluorescence showed ASPC-1 with higher accumulation of VP 3 hrs after injection and more VP at a distance from blood vessels compared to Panc-1. This work shows the need for techniques to analyze photosensitizer distribution in order to optimize photodynamic therapy as an effective treatment for pancreatic tumors.

  19. Tracer-based laser-induced fluorescence measurement technique for quantitative fuel/air-ratio measurements in a hydrogen internal combustion engine.

    Science.gov (United States)

    Blotevogel, Thomas; Hartmann, Matthias; Rottengruber, Hermann; Leipertz, Alfred

    2008-12-10

    A measurement technique for the quantitative investigation of mixture formation processes in hydrogen internal combustion engines (ICEs) has been developed using tracer-based laser-induced fluorescence (TLIF). This technique can be employed to fired and motored engine operation. The quantitative TLIF fuel/air-ratio results have been verified by means of linear Raman scattering measurements. Exemplary results of the simultaneous investigation of mixture formation and combustion obtained at an optical accessible hydrogen ICE are shown.

  20. A review of current smoke constituent measurement activities and aspects of yield variability.

    Science.gov (United States)

    Purkis, Stephen W; Meger, Michael; Wuttke, Roland

    2012-02-01

    An increasing number of initiatives to regulate cigarette smoke constituents beyond 'tar', nicotine and carbon monoxide are being launched. The objective of existing and proposed regulation is presumably either to gain a better understanding of product performance, to be able to discriminate between products, or to impose limits for selected constituents. However, without standardized analytical methods and measurement tolerances a meaningful comparison of data or verification against regulated limits is challenging if not impossible. Hence, an understanding of the validity and limitations of generated data is important for industry and regulators alike to avoid unjustified 'out-of-compliance' situations, and consequent competitive and reputational concerns for manufacturers. This paper reviews smoke constituent regulation and provides examples of technical challenges and good practice. It discusses approaches used to standardize measurements; the role of the International Organization for Standardization; factors influencing result variability and limitations and possible misinterpretations of generated data. If smoke constituents regulation is to be introduced, a standardized, science-based approach must be the pre-requisite for the generation and comparison of data. Potential analytical and technical issues must be resolved in discussion, both before and after the implementation of regulation, to the benefit of the public, regulators and manufacturers.

  1. Note: Design of a full photon-timing recorder down to 1-ns resolution for fluorescence fluctuation measurements

    Energy Technology Data Exchange (ETDEWEB)

    Nishimura, Goro, E-mail: gnishi@imd.es.hokudai.ac.jp [Research Institute for Electronic Science, Hokkaido University, Sapporo 001-0020 (Japan)

    2015-10-15

    A photon timing recorder was realized in a field programmable gate array to capture all timing data of photons on multiple channels with down to a 1-ns resolution and to transfer all data to a host computer in real-time through universal serial bus with more than 10 M events/s transfer rate. The main concept is that photon time series can be regarded as a serial communication data stream. This recorder was successfully applied for simultaneous measurements of fluorescence fluctuation and lifetime of near-infrared dyes in solution. This design is not only limited to the fluorescence fluctuation measurement but also applicable to any kind of photon counting experiments in a nanosecond time range because of the simple and easily modifiable design.

  2. Non-invasive detection of iron deficiency by fluorescence measurement of erythrocyte zinc protoporphyrin in the lip.

    Science.gov (United States)

    Hennig, Georg; Homann, Christian; Teksan, Ilknur; Hasbargen, Uwe; Hasmüller, Stephan; Holdt, Lesca M; Khaled, Nadia; Sroka, Ronald; Stauch, Thomas; Stepp, Herbert; Vogeser, Michael; Brittenham, Gary M

    2016-02-17

    Worldwide, more individuals have iron deficiency than any other health problem. Most of those affected are unaware of their lack of iron, in part because detection of iron deficiency has required a blood sample. Here we report a non-invasive method to optically measure an established indicator of iron status, red blood cell zinc protoporphyrin, in the microcirculation of the lower lip. An optical fibre probe is used to illuminate the lip and acquire fluorescence emission spectra in ∼1 min. Dual-wavelength excitation with spectral fitting is used to distinguish the faint zinc protoporphyrin fluorescence from the much greater tissue background fluorescence, providing immediate results. In 56 women, 35 of whom were iron-deficient, the sensitivity and specificity of optical non-invasive detection of iron deficiency were 97% and 90%, respectively. This fluorescence method potentially provides a rapid, easy to use means for point-of-care screening for iron deficiency in resource-limited settings lacking laboratory infrastructure.

  3. Development of a homogeneous fluorescence anisotropy assay to monitor and measure FtsZ assembly in solution.

    Science.gov (United States)

    Reija, Belén; Monterroso, Begoña; Jiménez, Mercedes; Vicente, Miguel; Rivas, Germán; Zorrilla, Silvia

    2011-11-01

    We present here a fluorescence anisotropy method for the quantification of the polymerization of FtsZ, an essential protein for cytokinesis in prokaryotes whose GTP-dependent assembly initiates the formation of the divisome complex. Using Alexa 488 labeled wild-type FtsZ as a tracer, the assay allows determination of the critical concentration of FtsZ polymerization from the dependence of the measured steady-state fluorescence anisotropy on the concentration of FtsZ. The incorporation of the labeled protein into FtsZ polymers and the lack of spectral changes on assembly were independently confirmed by time-resolved fluorescence and fluorescence correlation spectroscopy. Critical concentration values determined by this new assay are compatible with those reported previously under the same conditions by other well-established methods. As a proof of principle, data on the sensitivity of the assay to changes in FtsZ assembly in response to Mg(2+) concentration or to the presence of high concentrations of Ficoll 70 as crowding agent are shown. The proposed method is sensitive, low sample consuming, rapid, and reliable, and it can be extended to other cooperatively polymerizing systems. In addition, it can help to discover new antimicrobials that may interfere with FtsZ polymerization because it can be easily adapted to systematic screening assays.

  4. Kinetics of a single cross-bridge in familial hypertrophic cardiomyopathy heart muscle measured by reverse Kretschmann fluorescence

    Science.gov (United States)

    Mettikolla, Prasad; Calander, Nils; Luchowski, Rafal; Gryczynski, Ignacy; Gryczynski, Zygmunt; Borejdo, Julian

    2010-01-01

    Familial hypertrophic cardiomyopathy (FHC) is a serious heart disease that often leads to a sudden cardiac death of young athletes. It is believed that the alteration of the kinetics of interaction between actin and myosin causes FHC by making the heart to pump blood inefficiently. We set out to check this hypothesis ex vivo. During contraction of heart muscle, a myosin cross-bridge imparts periodic force impulses to actin. The impulses are analyzed by fluorescence correlation spectroscopy (FCS) of fluorescently labeled actin. To minimize observation volume and background fluorescence, we carry out FCS measurements in surface plasmon coupled emission mode in a reverse Kretschmann configuration. Fluorescence is a result of near-field coupling of fluorophores excited in the vicinity of the metal-coated surface of a coverslip with the surface plasmons propagating in the metal. Surface plasmons decouple on opposite sides of the metal film and emit in a directional manner as far-field p-polarized radiation. We show that the rate of changes of orientation is significantly faster in contracting cardiac myofibrils of transgenic mice than wild type. These results are consistent with the fact that mutated heart muscle myosin translates actin faster in in vitro motility assays.

  5. Energy Yield Determination of Concentrator Solar Cells using Laboratory Measurements: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Geisz, John F.; Garcia, Ivan; McMahon, William E.; Steiner, Myles A.; Ochoa, Mario; France, Ryan M.; Habte, Aron; Friedman, Daniel J.

    2015-09-14

    The annual energy conversion efficiency is calculated for a four junction inverted metamorphic solar cell that has been completely characterized in the laboratory at room temperature using measurements fit to a comprehensive optoelectronic model of the multijunction solar cells. A simple model of the temperature dependence is used to predict the performance of the solar cell under varying temperature and spectra characteristic of Golden, CO for an entire year. The annual energy conversion efficiency is calculated by integrating the predicted cell performance over the entire year. The effects of geometric concentration, CPV system thermal characteristics, and luminescent coupling are highlighted. temperature and spectra characteristic of Golden, CO for an entire year. The annual energy conversion efficiency is calculated by integrating the predicted cell performance over the entire year. The effects of geometric concentration, CPV system thermal characteristics, and luminescent coupling are highlighted.

  6. Annular shape silver lined proportional counter for on-line pulsed neutron yield measurement

    Science.gov (United States)

    Dighe, P. M.; Das, D.

    2015-04-01

    An annular shape silver lined proportional counter is developed to measure pulsed neutron radiation. The detector has 314 mm overall length and 235 mm overall diameter. The central cavity of 150 mm diameter and 200 mm length is used for placing the neutron source. Because of annular shape the detector covers >3π solid angle of the source. The detector has all welded construction. The detector is developed in two halves for easy mounting and demounting. Each half is an independent detector. Both the halves together give single neutron pulse calibration constant of 4.5×104 neutrons/shot count. The detector operates in proportional mode which gives enhanced working conditions in terms of dead time and operating range compared to Geiger Muller based neutron detectors.

  7. D1-arginine257 mutants (R257E, K, and Q) of Chlamydomonas reinhardtii have a lowered QB redox potential: analysis of thermoluminescence and fluorescence measurements

    Science.gov (United States)

    Rose, Stuart; Minagawa, Jun; Seufferheld, Manfredo; Padden, Sean; Svensson, Bengt; Kolling, Derrick R. J.; Crofts, Antony R.; Govindjee

    2009-01-01

    Arginine257 (R257), in the de-helix that caps the QB site of the D1 protein, has been shown by mutational studies to play a key role in the sensitivity of Photosystem II (PS II) to bicarbonate-reversible binding of the formate anion. In this article, the role of this residue has been further investigated through D1 mutations (R257E, R257Q, and R257K) in Chlamydomonas reinhardtii. We have investigated the activity of the QB site by studying differences from wild type on the steady-state turnover of PS II, as assayed through chlorophyll (Chl) a fluorescence yield decay after flash excitation. The effects of p-benzoquinone (BQ, which oxidizes reduced QB, QB−) and 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU, which blocks electron flow from QA− to QB) were measured. The equilibrium constants of the two-electron gate were obtained through thermoluminescence measurements. The thermoluminescence properties were changed in the mutants, especially when observed after pretreatment with 100 μM BQ. A theoretical analysis of the thermoluminescence data, based mainly on the recombination pathways model of Rappaport et al. (2005), led to the conclusion that the free-energy difference for the recombination of QB− with S2 was reduced by 20–40 mV in the three mutants (D1-R257K, D1-R257Q, and D1-R257E); this was interpreted to be due to a lowering of the redox potential of QB/QB−. Further, since the recombination of QA− with S2 was unaffected, we suggest that no significant change in redox potential of QA/QA− occurred in these three mutants. The maximum variable Chl a fluorescence yield is lowered in the mutants, in the order R257K > R257Q > R257E, compared to wild type. Our analysis of the binary oscillations in Chl a fluorescence following pretreatment of cells with BQ showed that turnover of the QB site was relatively unaffected in the three mutants. The mutant D1-R257E had the lowest growth rate and steady-state activity and showed the weakest binary oscillations

  8. Detection of the onset of glyphosate-induced soybean plant injury through chlorophyll fluorescence signal extraction and measurement

    Science.gov (United States)

    Zhao, Feng; Guo, Yiqing; Huang, Yanbo; Reddy, Krishna N.; Zhao, Yanhua; Molin, William T.

    2015-01-01

    In this study, chlorophyll fluorescence (ChlF) was used to detect the onset of soybean plant injury from treatment of glyphosate, the most widely used herbicide. Thirty-six pots of nonglyphosate-resistant soybean were randomly divided into three groups and treated with different doses of glyphosate solutions. The three treatment groups were control (CTRL) group (with no glyphosate treatment), 0.25X group (treated with 0.217 kg.ae/ha solution of glyphosate), and 0.5X group (treated with 0.433 kg.ae/ha solution of glyphosate). Three kinds of fluorescence measurements, steady-state fluorescence spectra, Kautsky effect parameters, and ChlF-related spectral indices were extracted and generated from the measurements in the glyphosate treatment experiment. The mean values of these fluorescence measurements for each of the CTRL group, the 0.25X group, and the 0.5X group were calculated. Glyphosate-induced leaf injury was then analyzed by examining the separability of these mean values at 6, 24, 48, and 72 hours after the treatment (HAT). Results indicate that the peak position of far-red ChlF shows an obvious blue shift for glyphosate-treated soybean, and peak values of steady-state fluorescence spectra for the three groups can be significantly distinguished from each other at 48 HAT and later. Four Kautsky effect parameters, Fv, Fv/Fm, Area, and PI, are parameters sensitive to glyphosate treatment, showing some differences between the CTRL group and treated groups at 24 HAT, and significant differences among the three groups at and beyond 48 HAT. Moreover, ChlF-related spectral indices, R6832/(R675.R690) and R690/R655, are also shown to be useful in detection of the glyphosate injury, though they are less effective than the steady-state fluorescence spectra and the Kautsky effect parameters. Based on the presented results, it can be concluded that glyphosate-induced soybean injury can be detected in a timely manner by the ChlF measurements, and this method has the

  9. Some fluorescence properties of dimethylaminochalcone and its novel cyclic analogues

    Science.gov (United States)

    Tomečková, Vladimíra; Poškrobová, Martina; Štefanišinová, Miroslava; Perjési, Pál

    2009-12-01

    This paper demonstrates the basic character (polarity, solubility, colour, absorption and fluorescence quantum yield) of synthetic dimethylaminochalcone ( 1) and its cyclic analogues measured in toluene, chloroform, dimethylsulfoxide and ethanol, which have been studied by absorption and fluorescence spectroscopy. The biologically active dye 4'-dimethylaminochalcone ( 1b) and its less flexible analogues 4-dimethylaminoindanone ( 2b), -tetralone ( 3b), and -benzosuberone ( 4b) are lipophilic molecules that displayed the best solubility in toluene and chloroform. The highest fluorescence and quantum yields of compounds 1 and 2 have been obtained in DMSO and chloroform. Quenching effect of fluorescence compounds ( 1- 4) has been studied in the mixture of the most polar organic solvents DMSO and water. In the presence of water, fluorescence of compound 1 has been quenched the best from all studied chalcones and emission maxima of molecules 1- 4 have been shifted to the longer wavelengths. Quenching effect of fluorescence by water was in order 1 > 2 > 3 > 4.

  10. Interpreting seasonal changes in the carbon balance of southern Amazonia using measurements of XCO2 and chlorophyll fluorescence from GOSAT

    OpenAIRE

    Parazoo, Nicholas C.; Bowman, Kevin; Frankenberg, Christian; Lee, Jung-Eun; Fisher, Joshua B.; Worden, John; Jones, Dylan B. A.; Berry, Joseph; Collatz, G James; Baker, Ian T.; Jung, Martin; Liu, Junjie; Osterman, Gregory; O'Dell, Chris; Sparks, Athena

    2013-01-01

    Amazon forests exert a major influence on the global carbon cycle, but quantifying the impact is complicated by diverse landscapes and sparse data. Here we examine seasonal carbon balance in southern Amazonia using new measurements of column-averaged dry air mole fraction of CO_2 (XCO_2) and solar induced chlorophyll fluorescence (SIF) from the Greenhouse Gases Observing Satellite (GOSAT) from July 2009 to December 2010. SIF, which reflects gross primary production (GPP), is used to disentang...

  11. CHANGES IN VALUES MEASURED WITH A LASER FLUORESCENCE SYSTEM FOR ENAMEL AND DENTIN ETHCED FOR DIFFERNT TIME INTERVALS - pilot study.

    Directory of Open Access Journals (Sweden)

    Radostina Anastasova

    2014-06-01

    Full Text Available Purpose: The aim of the presented in vitro study was to evaluate the effectiveness of the laser fluorescent device DIAGNOdent in measuring changes in the level of mineralization of intact enamel surfaces etched for different time intervals and intact dentin etched for 30 sec. Material and methods: The study was performed on extracted human teeth. DIAGNOcam was used to measure the values of laser fluorescence of intact enamel and dentinal surfaces. Then the samples were treated with 37% H2PO3 etchant for 5, 30 and 60 sec for enamel surfaces and 30 sec for dentinal. Teeth were rinsed, dried and measured again with DIAGNOdent. Statistical analysis was done using statistical software SPSS 16.0 (SPSS Inc.. Results: After etching the enamel surfaces for 5, 30 and 60 seconds an average increase of 0,5 (0.62-1.1 was detected. The detected average values of increase of laser fluorescence for the enamel were 0.5 for 5 sec. ethching, 0.62 for 30 sec and 1.1 for 60 sec. The average increase for dentine was 0.26. Conclusions: Based on the limitations of the conducted study it may be concluded that changes in the degree of mineralization of tooth structures can be detected by using DIAGNOdent. Enamel etching for 5 sec and 30 sec lead to a comparative degree of change in the laser fluorescence. The obtained values after 60 sec. of etching revealed an almost double increase. The measured changes in enamel after etching are better pronounced than that in dentin.

  12. CONTINUOUS MEASUREMENT OF THE CYTOPLASMIC PH IN LACTOCOCCUS-LACTIS WITH A FLUORESCENT PH INDICATOR

    NARCIS (Netherlands)

    MOLENAAR, D; ABEE, T; KONINGS, WN

    1991-01-01

    The cytoplasmic pH of Lactococcus lactis was studied with the fluorescent pH indicator 2',7'-bis-(2-carboxyethyl)-5 (and-6)-carboxyfluorescein (BCECF). A novel method was applied for loading bacterial cells with BCECF, which consists of briefly treating a dense cell suspension with acid in the prese

  13. Understanding Fluorescence Measurements through a Guided-Inquiry and Discovery Experiment in Advanced Analytical Laboratory

    Science.gov (United States)

    Wilczek-Vera, Grazyna; Salin, Eric Dunbar

    2011-01-01

    An experiment on fluorescence spectroscopy suitable for an advanced analytical laboratory is presented. Its conceptual development used a combination of the expository and discovery styles. The "learn-as-you-go" and direct "hands-on" methodology applied ensures an active role for a student in the process of visualization and discovery of concepts.…

  14. CONTINUOUS MEASUREMENT OF THE CYTOPLASMIC PH IN LACTOCOCCUS-LACTIS WITH A FLUORESCENT PH INDICATOR

    NARCIS (Netherlands)

    MOLENAAR, D; ABEE, T; KONINGS, WN

    1991-01-01

    The cytoplasmic pH of Lactococcus lactis was studied with the fluorescent pH indicator 2',7'-bis-(2-carboxyethyl)-5 (and-6)-carboxyfluorescein (BCECF). A novel method was applied for loading bacterial cells with BCECF, which consists of briefly treating a dense cell suspension with acid in the

  15. Near-field measurements of vegetation by laser-induced fluorescence imaging

    Science.gov (United States)

    Sowinska, Malgorzata; Cunin, Bernard; Deruyver, Aline; Heisel, Francine; Miehe, Joseph-Albert; Langsdorf, Gabriele; Lichtenthaler, Hartmut K.

    1999-12-01

    In this paper, a validation of a new UV-A laser-induced fluorescence imaging system implemented in an all-road car for near-field remote sensing of vegetation will be presented. It has been developed as a part of a European Community Program INTERREG II and is consisting of three main parts: excitation, detection and control units. The excitation source is a frequency tripled Nd:YAG laser and the laser spot size is adjusted via a variable beam expander. Fluorescence images are recorded at four characteristic fluorescence bands: 440, 520, 690 and 740 nm with a gated intensified digital CCD camera. The laser head and camera are situated on a directed in site and azimuth platform which can be high up to 6 meters. The platform positioning, localization and distance detection, spot size determination and adjustment, focus, sharpness, selection of the filter, laser and camera synchronization, gain of the intensifier, real time visualization of images, acquisition time are controlled by a newly developed software which allows also image storage, analysis and treatment. Examples of remote sensing fluorescence images from several plant species recorded at a distance of 10 - 30 m will be given and discussed further in this paper.

  16. Fluorescence lidar measurements at the archaeological site House of Augustus at Palatino, Rome

    Science.gov (United States)

    Raimondi, Valentina; Alisi, Chiara; Barup, Kerstin; Bracciale, Maria Paola; Broggi, Alessandra; Conti, Cinzia; Hällström, Jenny; Lognoli, David; Palombi, Lorenzo; Santarelli, Maria Laura; Sprocati, Anna Rosa

    2013-10-01

    Early diagnostics and documentation fulfill an essential role for an effective planning of conservation and restoration of cultural heritage assets. In particular, remote sensing techniques that do not require the use of scaffolds or lifts, such as fluoresence lidar, can provide useful information to obtain an overall assessment of the status of the investigated surfaces and can be exploited to address analytical studies in selected areas. Here we present the results of a joint Italian-Swedish project focused on documenting and recording the status of some sections of the part closed to the public by using fluorescence hyperspectral imaging lidar. The lidar used a tripled-frequency Nd:YAG laser emitting at 355 nm as excitation source and an intensified, gated 512x512-pixel CCD as detector. The lidar had imaging capabilities thanks to a computer-controlled scanning mirror. The fluorescence characteristics of fresco wall paintings were compared to those of fresco fragments found at the same archaeological site and separately examined in the lab using FT-IR and Raman techniques for the identification of pigments. The fluorescence lidar was also used to remotely detect the growth of phototrophic biodeteriogens on the walls. The fluorescence lidar data were compared with results from biological sampling, cultivation and laboratory analysis by molecular techniques.

  17. CONTINUOUS MEASUREMENT OF THE CYTOPLASMIC PH IN LACTOCOCCUS-LACTIS WITH A FLUORESCENT PH INDICATOR

    NARCIS (Netherlands)

    MOLENAAR, D; ABEE, T; KONINGS, WN

    1991-01-01

    The cytoplasmic pH of Lactococcus lactis was studied with the fluorescent pH indicator 2',7'-bis-(2-carboxyethyl)-5 (and-6)-carboxyfluorescein (BCECF). A novel method was applied for loading bacterial cells with BCECF, which consists of briefly treating a dense cell suspension with acid in the prese

  18. A convenient method for experimental determination of yields and isomeric ratios in photonuclear reactions measured by the activation technique

    Science.gov (United States)

    Kolev, D.; Dobreva, E.; Nenov, N.; Todorov, V.

    1995-02-01

    A generalized exact formula is derived for a determination of the experimental isomeric ratio in any incident particle activation. For the particular case, when the activity of the ground state results from the simultaneous decay of both states and can be conveniently measured, the appropriate modification of this formula is evaluated and applied to six photonuclear reactions induced by 43 MeV bremsstrahlung. The experimental isomeric yield ratios of (γ, 3n) 110m,gIn; (γ, p) (γ, pn), (γ, 2n2p) 117m,gIn; (γ, n) 164m,gHo and (γ, 3n) 162m,gHo are deduced.

  19. Measurement of thick target neutron yields for protons and deuterons in Ten's of MeV region

    Energy Technology Data Exchange (ETDEWEB)

    Baba, M.; Aoki, T.; Kawata, N.; Hagiwara, M.; Miura, T.; Yamadera, A.; Yonai, S.; Nakamura, T. [Tohoku Univ., Sendai (Japan)

    2002-07-01

    We have measured energy-angular differential thick target neutron yields (TTY) for C, Al, Ta, W(p,n) reactions at 50 MeV, and Li, Be (d,n) reactions for 25 MeV deuterons with the TOF method using Tohoku University K=110 MeV cyclotron equipped with a beam swinger system and a well collimated TOF line. Neutron spectrum data have been obtained down to {approx} 0.8 MeV from the highest energy at several laboratory angles from 0-deg to 90-deg. The results are compared with other experiments and a recent data library LA-150.

  20. Measurement of the effective B{sub s}{sup 0}{yields}K{sup +}K{sup -} lifetime

    Energy Technology Data Exchange (ETDEWEB)

    Aaij, R. [Nikhef National Institute for Subatomic Physics, Amsterdam (Netherlands); Abellan Beteta, C. [Universitat de Barcelona, Barcelona (Spain); Adeva, B. [Universidad de Santiago de Compostela, Santiago de Compostela (Spain); Adinolfi, M. [H.H. Wills Physics Laboratory, University of Bristol, Bristol (United Kingdom); Adrover, C. [CPPM, Aix-Marseille Universite, CNRS/IN2P3, Marseille (France); Affolder, A. [Oliver Lodge Laboratory, University of Liverpool, Liverpool (United Kingdom); Ajaltouni, Z. [Clermont Universite, Universite Blaise Pascal, CNRS/IN2P3, LPC, Clermont-Ferrand (France); Albrecht, J.; Alessio, F. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Alexander, M. [School of Physics and Astronomy, University of Glasgow, Glasgow (United Kingdom); Alkhazov, G. [Petersburg Nuclear Physics Institute (PNPI), Gatchina (Russian Federation); Alvarez Cartelle, P. [Universidad de Santiago de Compostela, Santiago de Compostela (Spain); Alves, A.A. [Sezione INFN di Roma La Sapienza, Roma (Italy); Amato, S. [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro (Brazil); Amhis, Y. [Ecole Polytechnique Federale de Lausanne (EPFL), Lausanne (Switzerland); Anderson, J. [Physik-Institut, Universitaet Zuerich, Zuerich (Switzerland); Appleby, R.B. [School of Physics and Astronomy, University of Manchester, Manchester (United Kingdom); Aquines Gutierrez, O. [Max-Planck-Institut fuer Kernphysik (MPIK), Heidelberg (Germany); Archilli, F. [Laboratori Nazionali dell' INFN di Frascati, Frascati (Italy); European Organization for Nuclear Research (CERN), Geneva (Switzerland); Arrabito, L. [CC-IN2P3, CNRS/IN2P3, Lyon-Villeurbanne (France); and others

    2012-02-01

    A measurement of the effective B{sub s}{sup 0}{yields}K{sup +}K{sup -} lifetime is presented using approximately 37 pb{sup -1} of data collected by LHCb during 2010. This quantity can be used to put constraints on contributions from processes beyond the Standard Model in the B{sub s}{sup 0} meson system and is determined by two complementary approaches as {tau}{sub KK}=1.440{+-}0.096 (stat){+-}0.008 (syst){+-}0.003 (model) ps.

  1. Cytoplasmic calcium measurement in rotavirus enterotoxin-enhanced green fluorescent protein (NSP4-EGFP) expressing cells loaded with Fura-2.

    Science.gov (United States)

    Berkova, Z; Morris, A P; Estes, M K

    2003-07-01

    The green fluorescent protein (GFP) and its analogs are standard markers of protein expression and intracellular localization of proteins. The fluorescent properties of GFP complicate accurate measurement of intracellular calcium using calcium sensitive fluorophores, which show a great degree of spectral overlap with GFP, or their K(d) values are too high for accurate measurement of subtle changes in cytoplasmic calcium concentrations. Here we describe a simple modification of the standard microscope-based Fura-2 calcium-imaging technique which permits the quantitative measurement of intracellular calcium levels in cells expressing enhanced green fluorescent protein (EGFP) fusion proteins. Longpass emission filtering of the Fura-2 signal in cells expressing an EGFP fusion protein is sufficient to eliminate the EGFP-Fura-2 emission spectra overlap and allows quantitative calibration of intracellular calcium. To validate this technique, we investigated the ability of rotavirus enterotoxin NSP4-EGFP to elevate intracellular calcium levels in mammalian HEK 293 cells. We show here that inducible intracellular expression of NSP4-EGFP fusion protein elevates basal intracellular calcium more than two-fold by a phospholipase C (PLC) independent mechanism.

  2. Intravital Fluorescence Facilitates Measurement of Multiple Physiologic Functions and Gene Expression in Tumors of Live Animals

    Directory of Open Access Journals (Sweden)

    Mark W. Dewhirst

    2002-01-01

    Full Text Available The purpose of this report is to present an overview of the use of fluorescence imaging in vivo, with particular emphasis on oncology. It is important to note, however, that many of the methods described herein have been applied to the study of non-malignant tissues as well. Modern medicine and biology research has benefited greatly from an ever-expanding assortment of fluorescent markers and labels. These markers and labels have allowed investigators to observe the behavior and properties of cell and molecular entities of interest in the context of complicated biological systems such as a mammalian cell or a whole mouse. Methods developed to image fluorescence in whole mice have been valuable in studying patterns of tumor growth and metastases. Alternatively, more detailed information and a wide variety of endpoints can be obtained using “intravital” preparations. This review focuses on use of fluorescence imaging for intravital preparations. For detail on fluorescence imaging of whole animals, refer to reviews on this subject [1,2]. For oncologic applications, studies have focused primarily on window chamber preparations that allow for real-time visualization of tumor growth, vascularity, vascular responses to stimulation, vascular permeability, vascular orientation, flow instability, and the like. These endpoints have been used to show that there are functional differences between tumor and normal tissues with respect to these functions under baseline conditions and after therapeutic manipulation. Examples of some of these differences are provided in this review as a means to illustrate how they can be used.

  3. Measurement of the ratio {gamma}(K{sub L}{yields}{gamma}{gamma})/{gamma}(K{sub L}{yields}{pi}{sup 0}{pi}{sup 0}{pi}{sup 0}) with the KLOE detector

    Energy Technology Data Exchange (ETDEWEB)

    Adinolfi, M.; Aloisio, A.; Ambrosino, F.; Antonelli, A.; Antonelli, M.; Bacci, C.; Bencivenni, G.; Bertolucci, S.; Bini, C.; Bloise, C.; Bocci, V.; Bossi, F.; Branchini, P.; Bulychjov, S.A.; Cabibbo, G.; Caloi, R.; Campana, P.; Capon, G.; Capussela, T.; Carboni, G.; Casarsa, M.; Casavola, V.; Cataldi, G.; Ceradini, F.; Cervelli, F.; Cevenini, F.; Chiefari, G.; Ciambrone, P.; Conetti, S.; De Lucia, E.; De Simone, P.; De Zorzi, G.; Dell' Agnello, S.; Denig, A.; Di Domenico, A.; Di Donato, C.; Di Falco, S.; Di Micco, B.; Doria, A.; Dreucci, M.; Erriquez, O.; Farilla, A.; Felici, G.; Ferrari, A.; Ferrer, M.L.; Finocchiaro, G.; Forti, C.; Franceschi, A.; Franzini, P.; Gatti, C.; Gauzzi, P.; Giannasi, A.; Giovannella, S.; Gorini, E.; Graziani, E.; Incagli, M.; Kluge, W.; Kulikov, V.; Lacava, F.; Lanfranchi, G.; Lee-Franzini, J.; Leone, D.; Lu, F.; Martemianov, M.; Matsyuk, M.; Mei, W.; Merola, L.; Messi, R.; Miscetti, S.; Moulson, M.; Mueller, S.; Murtas, F.; Napolitano, M.; Nedosekin, A.; Nguyen, F.; Palomba, M.; Pacciani, L.; Palutan, M.; Pasqualucci, E.; Passalacqua, L.; Passeri, A.; Patera, V.; Perfetto, F.; Petrolo, E.; Pirozzi, G.; Pontecorvo, L.; Primavera, M.; Ruggieri, F.; Santangelo, P.; Santovetti, E.; Saracino, G.; Schamberger, R.D.; Sciascia, B.; Sciubba, A.; Scuri, F.; Sfiligoi, I.; Sibidanov, A.; Spadaro, T.; Spiriti, E.; Tabidze, M.; Tong, G.L.; Tortora, L.; Valente, P.; Valeriani, B.; Venanzoni, G.; Veneziano, S.; Ventura, A.; Ventura, S.; Versaci, R

    2003-07-24

    We have measured the ratio R={gamma}(K{sub L}{yields}{gamma}{gamma})/{gamma}(K{sub L}{yields}{pi}{sup 0}{pi}{sup 0}{pi}{sup 0}) using the KLOE detector. From a sample of {approx}10{sup 9} phi-mesons produced at DAPHINE, the Frascati phi-factory, we select {approx}1.6x10{sup 8} K{sub L}-mesons tagged by observing K{sub S}{yields}{pi}{sup +}{pi}{sup -} following the reaction e{sup +}e{sup -}{yields}phi{yields}K{sub L}K{sub S}. From this sample we select 27,375 K{sub L}{yields}{gamma}{gamma} events and obtain R=(2.79{+-}0.02{sub stat}{+-}0.02{sub syst})x10{sup -3}. Using the world average value for BR(K{sub L}{yields}{pi}{sup 0}{pi}{sup 0}{pi}{sup 0}), we obtain BR(K{sub L}{yields}{gamma}{gamma})=(5.89{+-}0.07{+-}0.08)x10{sup -4} where the second error is due to the uncertainty on the {pi}{sup 0}{pi}{sup 0}{pi}{sup 0} branching fraction.

  4. A fusion-spliced near-field optical fiber probe using photonic crystal fiber for nanoscale thermometry based on fluorescence-lifetime measurement of quantum dots.

    Science.gov (United States)

    Fujii, Takuro; Taguchi, Yoshihiro; Saiki, Toshiharu; Nagasaka, Yuji

    2011-01-01

    We have developed a novel nanoscale temperature-measurement method using fluorescence in the near-field called fluorescence near-field optics thermal nanoscopy (Fluor-NOTN). Fluor-NOTN enables the temperature distributions of nanoscale materials to be measured in vivo/in situ. The proposed method measures temperature by detecting the temperature dependent fluorescence lifetimes of Cd/Se quantum dots (QDs). For a high-sensitivity temperature measurement, the auto-fluorescence generated from a fiber probe should be reduced. In order to decrease the noise, we have fabricated a novel near-field optical-fiber probe by fusion-splicing a photonic crystal fiber (PCF) and a conventional single-mode fiber (SMF). The validity of the novel fiber probe was assessed experimentally by evaluating the auto-fluorescence spectra of the PCF. Due to the decrease of auto-fluorescence, a six- to ten-fold increase of S/N in the near-field fluorescence lifetime detection was achieved with the newly fabricated fusion-spliced near-field optical fiber probe. Additionally, the near-field fluorescence lifetime of the quantum dots was successfully measured by the fabricated fusion-spliced near-field optical fiber probe at room temperature, and was estimated to be 10.0 ns.

  5. A Fusion-Spliced Near-Field Optical Fiber Probe Using Photonic Crystal Fiber for Nanoscale Thermometry Based on Fluorescence-Lifetime Measurement of Quantum Dots

    Directory of Open Access Journals (Sweden)

    Toshiharu Saiki

    2011-08-01

    Full Text Available We have developed a novel nanoscale temperature-measurement method using fluorescence in the near-field called Fluorescence Near-field Optics Thermal Nanoscopy (Fluor-NOTN. Fluor-NOTN enables the temperature distributions of nanoscale materials to be measured in vivo/in situ. The proposed method measures temperature by detecting the temperature dependent fluorescence lifetimes of Cd/Se Quantum Dots (QDs. For a high-sensitivity temperature measurement, the auto-fluorescence generated from a fiber probe should be reduced. In order to decrease the noise, we have fabricated a novel near-field optical-fiber probe by fusion-splicing a photonic crystal fiber (PCF and a conventional single-mode fiber (SMF. The validity of the novel fiber probe was assessed experimentally by evaluating the auto-fluorescence spectra of the PCF. Due to the decrease of auto-fluorescence, a six- to ten-fold increase of S/N in the near-field fluorescence lifetime detection was achieved with the newly fabricated fusion-spliced near-field optical fiber probe. Additionally, the near-field fluorescence lifetime of the quantum dots was successfully measured by the fabricated fusion-spliced near-field optical fiber probe at room temperature, and was estimated to be 10.0 ns.

  6. 奶牛产奶量测量系统设计%Design of milk yield measurement system

    Institute of Scientific and Technical Information of China (English)

    戴建国; 李栓明; 周涛; 隋贤俊; 郑瑶; 张瑞敏; 张卫东

    2012-01-01

    为了快速、准确地获取奶牛产奶量数据,避免目前常用的间接测量方法产生的误差,设计了基于质量计量的奶量采集系统.该系统通过在奶罐下安置基于压力传感器的质量称量机,将压力产生的模拟电信号通过A/D转换模块转变为数字电信号,再经分级处理从而获取牛奶质量数据,并直接上传至上位机.上、下位机之间通过CAN总线连接,基于自主协议进行相互通信.经多次测试表明,在5~35 kg范围内该系统的测量误差可以控制在6%以下,且具有采集速度快、容错性强的特点.%In order to collect milk yield data rapidly and accurately, avoid the measurement error caused by commonly indirect measurement methods used at present, a milk yield collection system based on mass measurement method was designed. A mass measurement device based on pressure sensor was placed under the milk container, and the measuring signal were transformed to digital signal by A/D module to obtain the milk yield data and upload them to host computer. In the system, CAN bus was used to connect the lower computer to host computer with self-developed communication protocol The test results show that the system has the features such as rapid collection, strong fault-tolerance, and the measurement error can be controlled less than 6% in the range from 5 kg to 35 kg.

  7. VCS-SSA Mainz Experiment. Measurement of the beam spin asymmetry in (e polarized p {yields} ep{gamma}) and (e polarized p {yields} ep{pi}{sup 0}). Final analysis - MEMO I

    Energy Technology Data Exchange (ETDEWEB)

    Fonvieille, H.; Bensafa, I. [LPC-Clermont-Fd, Universite Blaise Pascal, F-63170 Aubiere Cedex (France)

    2006-02-15

    This note gives details on the final analysis of the VCS-SSA experiment in terms of Beam Spin Asymmetry. It summarizes the changes between the first and second pass analysis. Then the measured asymmetry is presented for both channels e polarized p {yields} ep{gamma} and e polarized p {yields} ep{pi}{sup 0} including systematic studies. The final experimental result is briefly compared to some model predictions. (authors)

  8. Neutron spectrum and yield of the Hiroshima A-bomb deduced from radionuclide measurements at one location.

    Science.gov (United States)

    Rühm, W; Kato, K; Korschinek, G; Morinaga, H; Nolte, E

    1995-07-01

    In this paper measurements of the radionuclides of 36Cl, 41Ca, 60Co, 152Eu and 154Eu in samples from Hiroshima, which were exposed to neutrons of the A-bomb explosion, are interpreted. In order to calculate the neutron spectrum at the sample site, neutron transport calculations using Monte Carlo techniques were carried out. Activation profiles in a granite mock-up irradiated with reactor neutrons could be reproduced by this method using DS86 input parameters. The calculated neutron spectrum at the sample site for non-thermal neutrons is identical to that obtained in DS86, but contains some 50% more thermal neutrons. The influence of parameters like soil composition, source terms and air humidity on the activation of these radioisotopes is discussed. The granite-covered earth at the sample site, for example, hardens the spectrum in comparison with DS86 values. Even when using a fission spectrum pointing downward and neglecting air humidity one cannot explain our 36Cl measurements. If the effective thermal neutron fluences, that have a similar ratio of resonance integral to thermal neutron capture cross sections obtained from 36Cl, 41Ca and 152Eu, are averaged, a bomb yield of about 16 kt is deduced in agreement with a bomb yield of (15 +/- 3) kt estimated in DS86.

  9. Intrinsic fluorescence of protein in turbid media using empirical relation based on Monte Carlo lookup table

    Science.gov (United States)

    Einstein, Gnanatheepam; Udayakumar, Kanniyappan; Aruna, Prakasarao; Ganesan, Singaravelu

    2017-03-01

    Fluorescence of Protein has been widely used in diagnostic oncology for characterizing cellular metabolism. However, the intensity of fluorescence emission is affected due to the absorbers and scatterers in tissue, which may lead to error in estimating exact protein content in tissue. Extraction of intrinsic fluorescence from measured fluorescence has been achieved by different methods. Among them, Monte Carlo based method yields the highest accuracy for extracting intrinsic fluorescence. In this work, we have attempted to generate a lookup table for Monte Carlo simulation of fluorescence emission by protein. Furthermore, we fitted the generated lookup table using an empirical relation. The empirical relation between measured and intrinsic fluorescence is validated using tissue phantom experiments. The proposed relation can be used for estimating intrinsic fluorescence of protein for real-time diagnostic applications and thereby improving the clinical interpretation of fluorescence spectroscopic data.

  10. Label-free silicon nanodots featured ratiometric fluorescent aptasensor for lysosomal imaging and pH measurement.

    Science.gov (United States)

    Zhang, Yanan; Guo, Shan; Cheng, Shibo; Ji, Xinghu; He, Zhike

    2017-03-22

    The homeostasis of lysosomal pH is crucial in cell physiology. Developing small fluorescent nanosensors for lysosome imaging and ratiometric measurement of pH is highly demanded yet challenging. Herein, a pH-sensitive fluorescein tagged aptamer AS1411 has been utilized to covalently modify the label-free fluorescent silicon nanodots via a crosslinker for construction of a ratiometric pH biosensor. The established aptasensor exhibits the advantages of ultrasmall size, hypotoxicity, excellent pH reversibility and good photostability, which favors its application in an intracellular environment. Using human breast MCF-7 cancer cells and MCF-10A normal cells as the model, this aptasensor shows cell specificity for cancer cells and displays a wide pH response range of 4.5-8.0 in living cells. The results demonstrate that the pH of MCF-7 cells is 5.1, which is the expected value for acidic organelles. Lysosome imaging and accurate measurement of pH in MCF-7 cells have been successfully conducted based on this nanosensor via fluorescent microscopy and flow cytometry.

  11. Time domain measuring system of molecular fluorescence with real-time monitor and control of pulsed dye laser

    Science.gov (United States)

    Taira, Y.; Suzuki, T.; Kato, H.; Konishi, N.; Kasuya, T.

    1982-04-01

    A computer controlled system is presented for a high-precision, time-domain measurement of molecular fluorescence induced by a pulsed dye laser field. In this system three intelligent functions are assembled by the system controller: they are an automatic wavelength control of pulsed dye laser to 0.45 GHz resolution, a digital wavelength meter of 10-7 precision, and a high-speed waveform digitizer with 10 ps inherent resolution. Then the system achieves a unique capability such as to record real-time data of fluorescence decay in the nanosecond regime under an on-line monitor and control of the laser wavelength to milliangstrom precision. The basic constitution and practical performance of the system are described with particular emphasis on its high precision and multi-task capability.