Chemical recycling of poly(ethylene terephthalate). Application to the synthesis of multiblock copolyesters

The chemical recycling of the poly(ethylene terephthalate), (PET), has been successfully carried out by glycolysis in the presence of bis (2-hydroxyethyl) terephthalate (BHET) resulting in the formation of hydroxytelechelic oligomers. These oligomers were then treated with carboxytelechelic poly(ε-caprolactone) oligomers of Mn = 2300 and Mn = 730 g•mol–1 molecular weight, in the absence or presence of the titanium tetrabutyloxide (Ti(OBu)4) as a catalyst to get multiblock copolyesters. The chemical structure of the synthesized copolyesters was investigated by size exclusion chromatography (SEC) and proton Nuclear Magnetic Resonance (1H NMR) spectroscopy. Moreover the differential scanning calorimetry (DSC) was used to explore their thermal properties. The ester-ester interchange reaction was observed between the two oligopolyesters, was studied and discussed in detail

Integrating anaerobic digestion and pyrolysis for treating digestates derived from sewage sludge and fat wastes

P. 32603-32614The coupling of biological and thermal technologies allows for the complete conversion of wastes into energy and biochar eliminating the problem of sludge disposal. The valorisation of fatty residues as co-substrate in a mesophilic digester of a wastewater treatment plant was studied considering an integrated approach of co-digestion and pyrolysis. Four digested samples obtained from co-digestion of sewage sludge and butcher’s fat waste were studied by thermogravimetric analysis. The activation energy corresponding to the sludge pyrolysis was calculated by a non-isothermal kinetic. Arrhenius activation energy was lower for the pyrolysis of a digested grease sample (92 kJ mol−1 obtained by OFW and 86 kJ mol−1 obtained by Vyazovkin) than for the pyrolysis of sewage sludge and its blends (164–190 kJ mol−1 obtained by OFW and 162–190 kJ mol−1 obtained by Vyazovkin). The analysis of the integrated approach of anaerobic co-digestion and pyrolysis of digestates demonstrated that the addition of 3% (w/v) of fat to the feeding sludge results in a 25% increase in the electricity obtained from biogas (if a combined heat and power unit is considered for biogas valorisation) and increasing the fat content to 15% allows for covering all thermal needs for drying of digestate and more than doubles (2.4 times) the electricity production when the scenario of digestion and pyrolysis is contemplated.S

Prévalence et facteurs de risque de la dysfonction érectile chez les insuffisants rénaux chroniques

Objectif: dépister la dysfonction érectile (DE) chez les insuffisants rénaux chroniques (IRC) et déterminer ses facteurs de risque. Patients et méthodes: Etude transversale auprès de 30 patients suivis pour une IRC. Tous les patients ont fait l’objet d’un dépistage de la dysfonction érectile à l’aide de l’indice international de la fonction érectile (IIEF-5). Résultats: L’âge moyen de nos patients était de 49,6 ± 9 ans. Le score IIEF moyen était de 15,62 ± 6,03. Le diagnostic de DE a été retenu chez 23 patients (76,7%). La prévalence de la DE était significativement plus élevée chez les insuffisants rénaux au stade terminal (89,5%) que chez ceux aux stades 3 et 4 (54,5%) (p=0,04). L’âge ≥ 50 ans, le tabagisme, le diabète, l’HTA, la dyslipidémie, l’obésité ou le surpoids, l’artériopathie distale, l’anémie ont été retrouvés respectivement dans 60,9%, 73,9%, 43,5%, 78,3%, 75%, 60,9%, 30,4% et 82,6% des cas. L’analyse statistique a montré que le tabagisme (OR = 17 ; IC : [1,68-171,7] ; p = 0,009), le stade terminal de l’IRC (OR =7,08 ; IC 95%: [1,07-46,67] ; p = 0,04) et l’HDLc bas (OR = 18 ; IC 95%: [1,19-271,46] ; p = 0,04) étaient les seuls facteurs de risque de la DE chez nos patients. Conclusions: La prévalence élevée de la DE et la multiplicité des facteurs de risque sont une nouvelle illustration de la gravité de ce trouble sexuel chez les insuffisants rénaux chronique

Light acclimation of leaf gas exchange in two Tunisian cork oak populations from contrasting environmental conditions

Due to diverse environmental conditions, Mediterranean plant populations are exposed to a range of selective pressures that may lead to phenotypic plasticity and local adaptation. We examined the effect of light acclimation on photosynthetic capacity in two Quercus suber (L.) populations that are native to different ecological conditions. Low-light adapted seedlings from both populations were exposed to three light treatments: full sunlight (HL), medium light (ML, 43% sunlight) and low light (LL, 15% sunlight) for one month. Photosynthetic performance was monitored by measuring leaf gas exchange and chlorophyll fluorescence parameters. The light environment influences light-saturated carbon assimilation (Amax) in the leaves of the population inhabiting the hot and dry region (from Gaafour). In contrast, there was no significant difference in Amax between leaves grown in high light and low light from Feija (the population native to a cold and humid climate), which suggests an inability of the Feija population to adjust its photosynthesis to respond to higher irradiance. The inability of the Feija population to adjust its photosynthesis did not result from a light acclimation failure in terms of chlorophyll content and ratio compared with the Gaafour population. Instead, it seems to be the consequence of lower stomatal conductance in the Feija population at HL compared to Gaafour