Interaction between maternal and offspring diet to impair vascular function and oxidative balance in high fat fed male mice

Aims: to determine the impact of maternal and post-weaning consumption of a high fat diet on endothelium-dependent vasorelaxation and redox regulation in adult male mouse offspring.Methods: female C57BL6J mice were fed an obesogenic high fat diet (HF, 45% kcal fat) or standard chow (C, 21% kcal fat) pre-conception and throughout pregnancy and lactation. Post-weaning, male offspring were continued on the same diet as their mothers or placed on the alternative diet to give 4 dietary groups (C/C, HF/C, C/HF and HF/HF) which were studied at 15 or 30 weeks of age.Results: there were significant effects of maternal diet on offspring body weight (p<0.004), systolic blood pressure (p = 0.026) and endothelium-dependent relaxation to ACh (p = 0.004) and NO production (p = 0.005) measured in the femoral artery. With control for maternal diet there was also an effect of offspring post-weaning dietary fat to increase systolic blood pressure (p<0.0001) and reduce endothelium-dependent relaxation (p = 0.022) and ACh-mediated NO production (p = 0.007). There was also a significant impact of age (p<0.005). Redox balance was perturbed, with altered regulation of vascular enzymes involved in ROS/NO signalling.Conclusions: maternal consumption of a HF diet is associated with changes in vascular function and oxidative balance in the offspring of similar magnitude to those seen with consumption of a high fat diet post-weaning. Further, this disadvantageous vascular phenotype is exacerbated by age to influence the risk of developing obesity, raised blood pressure and endothelial dysfunction in adult lif

Pyrolysis of wood and PVC mixtures: thermal behaviour and kinetic modelling

International audienceWood waste containing halogenated compounds such as polyvinyl chloride (PVC) is in abundant supply, although the pyrolysis of such waste feedstock for energy production may cause corrosion and environmental problems due to the release of HCl gas. Hence, there is a need to understand the pyrolysis behaviour of chlorine-contaminated wood in order to develop methods that minimise the impact of chloride species on pyrolysis equipment and product quality. In literature, few studies exist on the kinetic analysis of wood and PVC co-pyrolysis. The existing models assume a single-step reaction with an n-order reaction mechanism for the entire process, which may lead to large errors in the kinetic parameters estimated. Therefore, in this paper, we develop and validate a multi-step kinetic model that predicts the pyrolysis behaviour and reaction mechanism of poplar wood (PW) pellet with different contents of PVC (0, 1, 5, 10, 100 wt%). Using data from thermogravimetric analysis of the pellets at heating rates of 5, 10 and 20 °C/min, we determined the apparent kinetic parameters by combining Fraser-Suzuki deconvolution, isoconversional methods and master plot procedures. Our model fitted the experimental data well with a deviation of less than 4.5%. Our results show that the addition of 1 wt% PVC to PW decreases the activation energy of hemicellulose and cellulose pyrolysis in PW from 136.3 to 101.6 kJ/mol and from 216.7 to 108.2 kJ/mol, respectively. This demonstrates the importance of acid hydrolysis reactions between the cellulosic fibres of PW and HCl released from PVC dehydrochlorination. Furthermore, we found that a nucleation and growth mechanism best represents the rate-limiting interactions between PVC and PW, which we linked to the formation of metal chloride crystals from acid-base reactions between HCl and PW minerals. Our kinetic model is an improvement of current models for the co-pyrolysis of wood and PVC, and can be readily used in a reactor-scale model of a pyrolyser or gasifier due to its relative simplicity