Dynamic Material Flow Analysis of PET, PE, and PP Flows in Europe: Evaluation of the Potential for Circular Economy.

This study evaluates the potential circularity of PET, PE, and PP flows in Europe based on dynamic material flow analysis (MFA), considering product lifetimes, demand growth rates, and quality reductions of recycled plastic (downcycling). The circularity was evaluated on a baseline scenario, representing 2016 conditions, and on prospective scenarios representing key circularity enhancing initiatives, including (i) maintaining constant plastic consumption, (ii) managing waste plastic exports in the EU, (iii) design-for-recycling initiatives, (iv) improved collection, and (v) improved recovery and reprocessing. Low recycling rates (RR, 13-20%) and dependence on virgin plastic, representing 85-90% of the annual plastic demand, were demonstrated after 50 years in the baseline. Limited improvements were related to the individual scenarios, insufficient to meet existing recycling targets. However, by combining initiatives, RRs above 55%, where 75-90% was recycled in a closed loop, were demonstrated. Moreover, 40-65% of the annual demand could potentially be covered by recycled plastic. Maintaining a constant plastic demand over time was crucial in order to reduce the absolute dependence on virgin plastic, which was not reflected by the RR. Thus, focusing strictly on RRs and even whether and to which extent virgin material is substituted, is insufficient for evaluating the transition toward circularity, which cannot be achieved by technology improvements alone-the demand must also be stabilized.

Waste management in the Irkutsk region, Siberia, Russia: An environmental assessment of alternative development scenarios.

The current waste management system, handling around 500,000 t of household, commercial, and institutional waste annually in the Irkutsk region, Siberia, is based on landfilling in an old landfill with no controls of leachate and gas. Life-cycle assessment modelling of the current system shows that it is a major load on the environment, while the simulation of seven alternative systems results in large savings in many impact categories. With respect to climate change, it is estimated that a saving of about 1200 kg CO2 equivalents is possible per year, per inhabitant, which is a significant reduction in greenhouse gas emissions. The best alternatives involve efficient energy recovery from waste and recycling by source separation for commercial and institutional waste, the major waste type in the Irkutsk region. Recycling of household waste seems less attractive, and it is therefore recommended only to consider this option after experience has been gained with the commercial and institutional waste. Sensitivity analysis shows that recovery of energy - in particular electricity, heat, and steam - from waste is crucial to the environmental performance of the waste management system. This relates to the efficiencies of energy recovery as well as what the recovered energy substitutes, that is, the 'dirtier' the off-set energy, the higher the environmental savings for the waste management system. Since recovered energy may be utilised by only a few energy grids or industrial users, it is recommended to perform additional local assessments of the integration of the waste energy into existing systems and facilities.

Reduction of insulinotropic properties of GLP-1 and GIP after glucocorticoid-induced insulin resistance.

AIMS/HYPOTHESIS: We evaluated the insulinotropic properties of glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) in healthy individuals at risk of developing type 2 diabetes before and after glucocorticoid-induced insulin resistance. METHODS: Nineteen healthy, glucose tolerant, first-degree relatives of type 2 diabetic patients underwent OGTT and 7 mmol/l and 15 mmol/l glucose clamps with concomitant infusions of GLP-1, GIP or NaCl and a final infusion of arginine for determination of maximum beta cell capacity before and after treatment with dexamethasone. In addition, first-phase insulin responses were determined at 7 mmol/l and 15 mmol/l and second-phase insulin responses at 7 mmol/l. RESULTS: After dexamethasone treatment, all 19 participants had increased insulin resistance (HOMA-IR and insulin sensitivity index [M/I] values) and 2 h plasma glucose concentrations, while beta cell function indices generally increased according to the increased resistance. First-phase insulin responses induced by GLP-1 and GIP at 7 mmol/l and maximal beta cell secretory capacity did not differ before and after dexamethasone, while second-phase responses to 7 mmol/l and first-phase responses to 15 mmol/l glucose were reduced equally for both hormones. CONCLUSIONS/INTERPRETATION: Glucocorticoid-induced insulin resistance in individuals at risk of type 2 diabetes leads to a reduced insulinotropic effect of the incretin hormones. This reduction was not associated with a decrease in the maximal beta cell secretory capacity, indicating that the reduced incretin effect in the developing dysglycaemia of the present experimental model is due to a specific early reduction of the insulinotropic effects of the incretin hormones. TRIAL REGISTRATION: Clinicaltrials.gov NCT02235584.