Jacques Feuillade

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Alkaline phosphatase activity (APA) was investigated monthly for 4 years in the eutrophic Lake Nantua, a lake colonized by a large population of Cyanobacteria. Total enzymatic activity as well as specific activities (the ratios between APA and biomass expressed as dry weight, chlorophyll a, cell phosphorus) varied strongly but they followed a similar(More)
The effect of light intensity on the release of dissolved organic carbon during photosynthesis on NaH14CO3 was investigated using the phytoplanktonic CyanobacteriumOscillatoria rubescens. The released products were fractionated by molecular size and chemical identifications attempted using combined thin-layer electrophoresis and chromatography, and high(More)
Gas vacuolation in Oscillatoria rubescens decreased with increased nitrogen limitation and increased with transitions from nitrogen to inorganic carbon limitation. Gas vacuoles consist of protein vesicles that can accumulate in carbon- limited but not in unenriched nitrogen-limited cells. Nitrogen limitation is a factor in the formation of deep population(More)
A new fixation method was developed for the Nuclear Magnetic Resonance (NMR) study of natural phytoplankton samples collected in situ. To test NMR reliability, a Chlorella continuous culture was used in a phosphorus deficiency recovery experiment. The method was then applied to natural metalimnetic cyanobacterial plankton. The maximum Entropy Method was(More)
The release of organic carbon by phytoplankton and its reassimilation by bacteria were studied in Lake Geneva during four daily kinetics, using14C techniques. Gentamycin was used to suppress bacterial activity. Size fractionation was used to measure14C fixation in 2 particulate fractions (≥1 μm and 0.2 to 1 μm) and in a third fraction: dissolved organic(More)
The rates of photosynthesis, respiration and carbon excretion by the cyanobacteriumOscillatoria rubescens D.C. were estimated at a range of light intensities between 0 and 60 μE m−2 s−1 (μmol photon m−2 s−1) using the14C method. A model of the evolution of cell carbon concentration based on the Hobsonet al. (1976) equations and taking excretion into account(More)
Short term14C labelling experiments and enzymatic activities related to primary pathways of photosynthesis have been studied in the cyanophytaOscillatoria rubescens D.C. from axenic cyclostat cultures. Responses of samples from cultures with different amounts of nitrogen are presented and compared. Variations in photosynthetic pigments are used to quantify(More)
The release of soluble organic carbon by the phytoplankton in the trophogenic layer of Lake Geneva has been investigated by14C method from March to November 1984. The carbon excretion rate varied from 0.01 to 0.5 mg C·m−3·h−1 and depended primarily upon the rate of its photosynthetic assimilation. The carbon excretion rate varied generally between 2 and 5%(More)
The proximity of organs at risk makes the treatment of head and neck squamous cell carcinoma (HNSCC) challenging by standard radiotherapy. The higher precision in tumor targeting of proton (P) therapy could promote it as the treatment of choice for HNSCC. Besides the physical advantage in dose deposition, few is known about the biological impact of P versus(More)
Brachytherapy consists in placing radioactive sources directly in contact with the tumoral bed. The type of source, its characteristics and its use will be adapted regarding the kind of treatment foreseen. Modern brachytherapy techniques employ remote afterloading technologies allowing better quality and security in the delivery of treatment. This(More)
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