Can net photosynthesis and water relations provide a clue on the forest decline of Quercus suber in North Tunisia?

Net photosynthesis, sap flow density (SFD) and water use efficiency (WUE) were measured in a Quercus suber forest in north Tunisia in an attempt to explain the forest decline. In general, sap flow was positively related to light intensity and water loss, indicating that high light intensities can increase the SFD up to the saturation point in the cork oak. CO2 assimilation of cork oak in this region was light intensity-dependent. Cork oak showed a general increase in photosynthetic rates with increasing light intensity up to the light saturation point. Increased radiation probably increased the photosynthesis and growth above ground in this area, whereas the below-ground soil had insufficient moisture for uptake through the roots because the high light intensity and temperature induced high evapotranspiration.Key words: Decline, evaportranspiration, light intensity, Quercus suber, sap flow density, water use efficiency

Synthèses, caractérisations structurales et dégradations thermiques de complexes anhydres triflato de dysprosium et d’holmium

La réaction d'une solution aqueuse de HOTf (OTf = O3SCF3) (0.5 ≤ M ≤ 1) avec les oxydes de lanthanides Ln2O3 (Ln = Dy et Ho) suivie d une déshydratation par voie thermique, sous vide dynamique, conduit aux complexes trifluorométhanesulfonates (triflates) anhydres Ln(OTf)3. Les rayons-X sur poudre montrent que ces complexes cristallisent dans le système monoclinique. La dégradation thermique des complexes Ln(OTf)3 conduit aux fluorures correspondants LnF3. La spectroscopie de vibration (IR et Raman) et l’analyse chimique indiquent que [OTf] est tridenté pontant et le centre métallique a une coordinence neuf. Ho(OTf)3 présente des phénomènes de fluorescence intenses, lors d’une excitation par la radiation 488 nm d un laser à argon ionisé, qui correspondent aux transitions (5Fa----->5I8 et 5S2---->5I8)

Effects of low dose radiation on atherosclerosis in APOE(-/-) mice: study of short term effects on macrophage polarization

International audienceAthersoclerosis is a chronic inflammatory disease of medium and large arteries that can lead to myocardial infarction or stroke. Mechanistic understanding of the effects of low-dose ionizing radiation (LDIR) on atherosclerosis remains incomplete. The experimental studies have shown a protective effect of LDIR on atherosclerosis in rodent models. However early responses of LDIR in different cell types that are known to be involved in atherosclerosis is not clear. The objective is to understand biological mechanisms of LDIR include on animal groups with multimodal approach. In this study, we report results of applying the foldchange, usually considered a relevant criterion for stating difference and similarity between measurements and a multilevel multivariate approach. Revealing complex correlations and causal links related to health conditions, such as atherosclerosis, can help advance the concept adverse outcome pathway (AOP)