J Fluorescence

The scope of this paper is to illustrate the need for an improved quality assurance in fluorometry. For this purpose, instrumental sources of error and their influences on the reliability and comparability of fluorescence data are highlighted for frequently used photoluminescence techniques ranging from conventional macro- and microfluorometry over fluorescence microscopy and flow cytometry to microarray technology as well as in vivo fluorescence imaging. Particularly, the need for and requirements on fluorescence standards for the characterization and performance validation of fluorescence instruments, to enhance the comparability of fluorescence data, and to enable quantitative fluorescence analysis are discussed. Special emphasis is dedicated to spectral fluorescence standards and fluorescence intensity standards

Ageing, resilience and depression:adding life to years as well as years to life

Wavelength-derivative of increment of refractive index of oxygenated and deoxygenated hemoglobin solutions from Kramers-Kronig relations. Originally published in Applied Optics on 01 November 2016 (ao-55-31-8951

Resolving power of diffraction imaging with an objective: a numerical study

Diffraction imaging in the far-field can detect 3D morphological features of an object for its coherent nature. We describe methods for accurate calculation and analysis of diffraction images of scatterers of single and double spheres by an imaging unit based on microscope objective at non-conjugate positions. A quantitative study of the calculated diffraction imaging in spectral domain has been performed to assess the resolving power of diffraction imaging. It has been shown numerically that with coherent illumination of 532 nm in wavelength the imaging unit can resolve single spheres of 2 μm or larger in diameters and double spheres separated by less than 300 nm between their centers.ECU Open Access Publishing Fun

HIGH RESOLUTION LASER SPECTROSCOPY OF ODD-PARITY BARIUM RYDBERG STATES POPULATED BY FORBIDDEN ATOMIC TRANSITIONS

Nous avons peuplé des niveaux de Rydberg impairs du baryum par la méthode d'excitation laser à deux étages en utilisant des transitions M1-E1 et E2-E1 à partir du niveau fondamental 6s2 1S0. A l'aide de deux lasers à colorant en anneau et d'une détection thermo-ionique, nous avons mesuré les spectres sans largeur Doppler des niveaux de Rydberg 6snp 1,3P et 6snf 1,3F en obtenant des rapports signal/bruit excellents. Nous avons étudié systématiquement la structure hyperfine des états de Rydberg 6snp 1P1. Entre n=20 et n=23, nous observons une résonance dûe au mélange singulet-triplet produit par l'interaction de configuration avec le niveau 5d8p 1P1 perturbateur proche de la limite d'ionisation. Nos résultats sont en désaccord avec une analyse existante de cette série à l'aide de la méthode du défaut quantique à plusieurs voies. Les mélanges singulet-triplet des séries de niveaux de Rydberg 6snp 1P1 et 6snd 1D2 sont comparés.Odd-parity barium Rydberg states have been populated by stepwise excitation via M1-E1 and E2-E1 transitions, starting from the 6s2 1S0 ground state. Using two cw dye ring lasers and employing thermionic detection, Doppler-free spectra of 6snp 1,3P and 6snf 1,3F Rydberg states have been recorded with excellent signal/noise ratios. A systematic study of the hyperfine structure of 6snp 1P1 Rydberg states has been carried out. Between n=20 and n=23 a resonance in singlet-triplet mixing occurs caused by configuration interaction with the 5d8p 1P1 perturbing state, located close to the first ionization limit. Our results are in disagreement with an existing multichannel quantum defect analysis of this series. The singlet-triplet mixing of 6snp 1P1 and 6snd 1D2 Rydberg series is compared

DataFile2.csv

spectra of the ensemble-averaged extinction cross section and refractive index of 2µm polystyrene spheres (Flow Check microparticles, Cat. No. 23526-10, Polysciences Europe GmbH, Germany

DataFile1.csv

spectra of the ensemble-averaged extinction cross section and refractive index of 2µm polystyrene spheres (dynospheres 50.010.SS-021 P, LOT Q262, Dyno Particles A.S., Norway

IMAGING OF LASER-INDUCED FLUORESCENCE EMITTED BY TUMOR LOCALIZING PHOTOSENSITIZERS

Photodynamic therapy is an experimental modality for the destruction of tumors or tumor cells by photochemical processes /1,2/. Such reactions are induced by exciting tumor-localizing photosensitizers by visible laser light. In addition to therapeutical applications, the characteristic fluorescence of the excited photosensitizers can be used for diagnostic purposes, i.e. for localization and imaging of tumors. The detection of small tumors as well as the determination of the extent of the lesion sensitively depend on the discrimination between sensitizer and tissue autofluorescence. This is particularly important at the boundary between tumor and normal tissue

Function of Hemoglobin Based Oxygen Carriers Determination of Methemoglobin Content by Spectral Extinction Measurements

Suspensions of hemoglobin microparticles HbMPs are promising tools as oxygen therapeutics. For the approval of clinical studies extensive characterization of these HbMPs with a size of about 750 nm is required regarding physical properties, function, pharmaco kinetics and toxicology. The standard absorbance measurements in blood gas analyzers require dissolution of red blood cells which does not work for HbMP. Therefore, we have developed a robust and rapid optical method for the quality and functionality control of HbMPs. It allows simultaneous determination of the portion of the two states of hemoglobin oxygenated hemoglobin oxyHb and deoxygenated hemoglobin deoxyHb as well as the content of methemoglobin metHb . Based on the measurement of collimated transmission spectra between 300 nm and 800 nm, the average extinction cross section of HbMPs is derived. A numerical method is applied to determine the composition of the HbMPs based on their wavelength dependent refractive index RI , which is a superposition of the three different states of Hb. Thus, light scattering properties, including extinction cross sections can be simulated for different compositions and sizes. By comparison to measured spectra, the relative concentrations of oxyHb, deoxyHb, metHb are accessible. For validation of the optically determined composition of the HbMPs, we used X ray fluorescence spectrometry for the ratio of Fe II oxyHb deoxyHb and Fe III metHb . High accuracy density measurements served to access heme free proteins, size was determined by dynamic light scattering and analytical centrifugation and the shape of the HbMPs was visualized by electron and atomic force microscop