69 research outputs found
Influence of phenolic acids on growth and inactivation of Oenococcus oeni and Lactobacillus hilgardii
Aims: To determine the effect of several wine-associated, phenolic acids on the growth and viability of strains of
Oenococcus oeni and Lactobacillus hilgardii.
Methods and Results: Growth was monitored in ethanol-containing medium supplemented with varying
concentrations of hydroxybenzoic acids (p-hydroxybenzoic, protocatechuic, gallic, vanillic and syringic acids) and
hydroxycinnamic acids (p-coumaric, caffeic and ferulic acids). Progressive inactivation was monitored in ethanolcontaining
phosphate buffer supplemented in a similar manner to the growth experiments. Hydroxycinnamic acids
proved to be more inhibitory to the growth of O. oeni than hydroxybenzoic acids. On the other hand, some acids
showed a beneficial effect on growth of Lact. hilgardii. p-Coumaric acid showed the strongest inhibitory effect on
growth and survival of both bacteria.
Conclusions: Most phenolic acids had a negative effect on growth of O. oeni, for Lact. hilgardii this effect was only
noted for p-coumaric acid. Generally, O. oeni was more sensitive to phenolic acid inactivation than Lact. hilgardii.
Significance and Impact of the Study: Eight wine-derived, phenolic acids were compared for their effects on
wine lactic acid bacteria. Results indicate that phenolic acids have the capacity to influence growth and survival
parameters. The differences found between phenolic compounds could be related to their different chemical
structures
D* Production in Deep Inelastic Scattering at HERA
This paper presents measurements of D^{*\pm} production in deep inelastic
scattering from collisions between 27.5 GeV positrons and 820 GeV protons. The
data have been taken with the ZEUS detector at HERA. The decay channel
(+ c.c.) has been used in the study. The
cross section for inclusive D^{*\pm} production with
and is 5.3 \pms 1.0 \pms 0.8 nb in the kinematic region
{ GeV and }. Differential cross
sections as functions of p_T(D^{*\pm}), and are
compared with next-to-leading order QCD calculations based on the photon-gluon
fusion production mechanism. After an extrapolation of the cross section to the
full kinematic region in p_T(D^{*\pm}) and (D^{*\pm}), the charm
contribution to the proton structure function is
determined for Bjorken between 2 10 and 5 10.Comment: 17 pages including 4 figure
Observation of Events with an Energetic Forward Neutron in Deep Inelastic Scattering at HERA
In deep inelastic neutral current scattering of positrons and protons at the center of mass energy of 300 GeV, we observe, with the ZEUS detector, events with a high energy neutron produced at very small scattering angles with respect to the proton direction. The events constitute a fixed fraction of the deep inelastic, neutral current event sample independent of Bjorken x and Q2 in the range 3 · 10-4 \u3c xBJ \u3c 6 · 10-3 and 10 \u3c Q2 \u3c 100 GeV2
New Colorimetric Micromethod for the Estimation of γ-Glutamyl Transpeptidase Activity in Biological Samples
Successful treatment of symptomatic hepatic cysts by single-shot instillation of minocycline chloride
Aspects complémentaires entre la spectroscopie d'absorption X et la diffraction anomale dans le cas d'entités de taille nanométrique supportés sur un oxyde léger : agrégats métalliques et oxyde de type spinelle
A combined approach based on X-ray Absorption Spectroscopy, classical X-Ray Diffraction and Anomalous Wide Angle X-ray Scattering has been used in the case of nanometer scale metallic particle supported on zeolite and for the supported system "Zn"/Al2O3. For the first material, we report a set of data obtained on a bimetallic PtCo catalyst. Exafs yields information on the local order around platinum before and after the reduction step. Also, diffraction experiments at two energies before the Pt Lm edge are reported and the results obtained from the two techniques are discussed. For the spinel, major information regarding the cation distribution, the electronic state of the metal atoms as well as the size of the zinc based metal oxide clusters are obtained. Through numerical simulations of the modulations of the X-rays absorption coefficient taking into account multiple scattering processes and ab initio calculations of the differential diffraction intensities based on the Debye equation, we have pointed out the fact that the tetrahedral site of the spinel occupied by the zinc atoms are partially occupied.La complémentarité entre deux techniques spécifiques au rayonnement synchrotron, la spectroscopie d'absorption X et la diffraction anomale est illustrée au travers l'étude d'entités de taille nanométrique déposées sur un oxyde léger. En premier lieu, une caractérisation d'agrégats métalliques Pt-Co déposés sur une zéolite montre tous les avantages d'une telle approche. Citons parmi eux, la détermination de la taille de la particule grâce à la connaissance du nombre de premier voisin métallique et de la nature du réseau cristallographique de la particule. Pour les oxydes divisés, cette démarche permet une mesure précise de l'état électronique du zinc, du taux d'occupation des sites tétraédriques ainsi que de la taille du cristallite de l'oxyde étudié
- …