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  • Analytical Chemistry and Spectroscopy  (6)
  • Membrane potential  (3)
  • 1
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Biochimica et Biophysica Acta (BBA)/Biomembranes 819 (1985), S. 206-214 
    ISSN: 0005-2736
    Keywords: (Plant) ; Isolated vacuole ; Liposome ; Membrane potential ; Probe binding ; Surface potential
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Medicine , Physics
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-2048
    Keywords: Auxin response mutant ; Fusicoccin ; Hypocotyl ; Membrane potential ; Nicotiana ; weak acid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The electrical response to the synthetic auxin 1-naphthaleneacetic acid (1-NAA) of Nicotiana plumbaginifolia wild type and the monogenic, dominant auxinresistant mutant R25 was studied. Membrane potentials were continuously recorded in hypocotyl cells of light-grown, intact seedlings, and the time course of the response to 1-NAA addition was followed. Wild-type cells responded to ⩾ 10−5 M 1-NAA with a delayed, transient hyperpolarization. The R25 cells hyperpolarized significantly only in response to 1-NAA at 10−3 M, and with maximal amplitudes lower than those recorded with the wild type. In contrast, the two genotypes reacted similarly in terms of kinetics and amplitude to 10−5 M fusicoccin, which rapidly and strongly hyperpolarized the cells, and to 10−3 M benzoic acid, which induced rapid and weak hyperpolarization. The resting membrane potentials of the wild type and R25 were also not significantly different. Unlike wild-type hypocotyls, those of R25 ceased elongating before the time chosen for the electrophysiological measurements, but control experiments performed at a time when the elongation of both genotypes had terminated indicated that the difference in electrical response to auxin is independent of hypocotyl growth. The inefficiency of 1-NAA in inducing hyperpolarization of R25 hypocotyl cells suggests a defect at an early step in auxin action.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-2048
    Keywords: Auxin response mutant ; Fusicoccin ; Hypocotyl ; Membrane potential ; Nicotiana ; weak acid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The electrical response to the synthetic auxin 1-naphthaleneacetic acid (1-NAA) ofNicotiana plumbaginifolia wild type and the monogenic, dominant auxinresistant mutant R25 was studied. Membrane potentials were continuously recorded in hypocotyl cells of light-grown, intact seedlings, and the time course of the response to 1-NAA addition was followed. Wild-type cells responded to ⩾ 10−5 M 1-NAA with a delayed, transient hyperpolarization. The R25 cells hyperpolarized significantly only in response to 1-NAA at 10−3 M, and with maximal amplitudes lower than those recorded with the wild type. In contrast, the two genotypes reacted similarly in terms of kinetics and amplitude to 10−5 M fusicoccin, which rapidly and strongly hyperpolarized the cells, and to 10−3 M benzoic acid, which induced rapid and weak hyperpolarization. The resting membrane potentials of the wild type and R25 were also not significantly different. Unlike wild-type hypocotyls, those of R25 ceased elongating before the time chosen for the electrophysiological measurements, but control experiments performed at a time when the elongation of both genotypes had terminated indicated that the difference in electrical response to auxin is independent of hypocotyl growth. The inefficiency of 1-NAA in inducing hyperpolarization of R25 hypocotyl cells suggests a defect at an early step in auxin action.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 7 (1980), S. 515-520 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Quantification of bile acids has been carried out by selected ion monitoring and by repetitive scanning. The latter method has been explored critically and found to be very suitable. A 24 h collection of feces was submitted to Soxhlet extraction. The extract was purified on Servachrom XAD-2, and separated into sulfated and nonsulfated fractions over DEAP-Sephadex-LH20. Conjugated and sulfated bile acids were enzymatically deconjugated and desulfated prior to permethylation. Deuterated bile acid derivatives were added as external standards and an aliquot was injected onto a capillary column of SE-52. The reconstructed chromatogram traces of specific ions were integrated to quantify known bile acids. Spectra of all metabolites were available for identification purposes simultaneously.
    Additional Material: 6 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    X-Ray Spectrometry 3 (1974), S. 59-63 
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Description / Table of Contents: Measurement of the extracellular fluid volume (ECFV) in the human body is an useful means of recognizing pathological conditions. X-ray fluorescence spectrometry allows a simple and accurate determination of the difusion space of bromide ions, from which the ECFV value can be calculated. The method consists of the quantitative determination of stable bromine (80Br) at low concentration in biological fluids, using the Br Kα line. A simultaneous study run with a radioactive tracer (82Br) allowed us to check the validity of the procedure.
    Notes: Le volume de liquide extracellualaire (LEC) chez l'homme estun parameétre important pour la deétection de certins eétats pathologiques. La spectromeétrie de fluorescence X permet de mesurer avec une bonne preécision I'espace de deffusion de I'ion bromure et d'en deédrire la valeur du volume de LEC. La meéthode consiste en un dosage direct du brome stabel (80Br) à faible concentration dans les liquides biologiques, en utilisant la raie Br Kα Une étude paralleéle au moyen d'un radiotraceur (82Br)permet de tester la valcur de la meéthode.
    Additional Material: 3 Ill.
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  • 6
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Description / Table of Contents: It can be interesting to determine bromine in a number of biological solutions, although the choice of method is made difficult by the occurrence of other elements. Yet, X-ray fluorescence spectrometric analysis appears suitable under certain conditions. The technique described here is based on the use of a non-dispersive X-ray fluorescence spectrometer, with 109Cd radioactive isotope as an excitation source. The factors studied are the system geometry, the volume of samples, the choice of cells and the reproducibility of measurements. Special conditions, as imposed by the collection of biological samples, are also considered.
    Notes: Il peut être intkréssant de doser le brome dans certains liquides biologiques. La présence d'autres éléments limite le choix des méthodes. L'analyse par spectrométric de fluorescence X paraít adaptée sous certaines conditions. Les auteurs décrivent une technique utilisant un spectromètre de fluorescence X non dispersif, dont la source d'excitation est constituée par un isotope radioactif: le Cadmium 109. Les facteurs de géométrie, le volume des échantillons, Ie choix des cellules, la reproductibilité des mesures sont étudiés, compte tenu des conditions imposées par le recueil des échantillons biologiques.
    Additional Material: 10 Ill.
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  • 7
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method has been developed for quantitative determination of pinaverium-bromide, a quaternary ammonium derivative with papaverine-like activity, in human serum. The method involves a chloroform extraction of serum spiked with N-(6,6-dimethyl bicyclo[3.1.1]2-heptenyl-ethoxyethyl)perhydro-1,4-oxazine as internal standard. After evaporation of the solvent, and reduction of the residue with Raney-Nickel, the internal standard and the reduced pinaverium-bromide are re-extracted from the reaction mixture with toluene and analysed isothermally on a fused silica column coated with OV-101. Although chemical ionization with methane revealed intense protonated molecular ions for both pinaverium-bromide and the internal standard, selectivity and sensitivity were significantly lower in comparison with electron impact ionization at 70 eV. Therefore, quantification was performed in the electron impact mode by single ion monitoring of the common fragment ion at m/z 100.2. A linear detector response was observed up to 160 ng ml-1. A within-run assay precision better than 2% CV (n=5) was found, and a detection limit of 1 ng pinaverium-bromide ml-1 of serum was attained.
    Additional Material: 7 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Journal of Raman Spectroscopy 7 (1978), S. 249-253 
    ISSN: 0377-0486
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Raman spectra of both polycrystalline samples and single crystals of CsAlCl4 and RbAlCl4 (space group Pnma (D2h16)) have been recorded in the temperature range 298-80 K.As for the other chloroaluminates, we find the four characteristic bands of the tetrahedral AlCl4- anion at 353, 128, 485-503, 180-187 cm-1 and 356, 127, 486-505 and 180-187 cm-1, respectively, for the salts CsAlCl4 and RbAlCl4. The Raman spectra of single crystals of these two compounds are similar and show that these two salts are isostructural. An assignment of the observed bands is proposed. The results are compared with those for the polyatomic cation (nitrosyl and ammonium) tetrachloroaluminates.
    Additional Material: 1 Ill.
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  • 9
    ISSN: 0377-0486
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The crystal structure of NaAlCl4 (a = 10.322(3) Å, b = 9.886(3) Å, c = 6.167(2) Å, Z = 4, space group P212121) was refined to final R and Rω values of 0.025 and 0.039 respectively, for 1240 reflections with I〉2σ(I). The thermal motion of the AlCl4- anion is in keeping with the TLS rigid-body analysis. Crystal and polycrystalline samples of this compound were studied by Raman scattering and an assignment of the observed bands was proposed. The Raman spectrum was compared with those of all members of alkaline (Li, Na, K, Rb, Cs) and pseudo-alkaline (NH4+, NO+) tetrachloroaluminates in the solid state.
    Additional Material: 5 Ill.
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