The lack of temporal information is an important limitation of life cycle assessment (LCA). A dynamic LCA approach is proposed to improve the accuracy of LCA by addressing the inconsistency of temporal assessment. This approach consists of first computing a dynamic life cycle inventory (LCI), considering the temporal profile of emissions. Then, time-dependent characterization factors are calculated to assess the dynamic LCI in real-time impact scores for any given time horizon. Although generally applicable to any impact category, this approach is developed here for global warming, based on the radiative forcing concept. This case study demonstrates that the use of global warming potentials for a given time horizon to characterize greenhouse gas emissions leads to an inconsistency between the time frame chosen for the analysis and the time period covered by the LCA results. Dynamic LCA is applied to the US EPA LCA on renewable fuels, which compares the life cycle greenhouse gas emissions of different biofuels with fossil fuels including land-use change emissions. The comparison of the results obtained with both traditional and dynamic LCA approaches shows that the difference can be important enough to change the conclusions on whether or not a biofuel meets some given global warming reduction targets.
Life cycle assessment (LCA) is a methodology that quantifies potential environmental impacts for comparative purposes in a decision-making context. While potential environmental impacts from pollutant emissions into water are characterized in LCA, impacts from water unavailability are not yet fully quantified. Water use can make the resource unavailable to other users by displacement or quality degradation. A reduction in water availability to human users can potentially affect human health. If financial resources are available, there can be adaptations that may, in turn, shift the environmental burdens to other life cycle stages and impact categories. This paper proposes a model to evaluate these potential impacts in an LCA context. It considers the water that is withdrawn and released, its quality and scarcity in order to evaluate the loss of functionality associated with water uses. Regionalized results are presented for impacts on human health for two modeling approaches regarding affected users, including or not domestic uses, and expressed in disability-adjusted life years (DALY). A consumption and quality based scarcity indicator is also proposed as a midpoint. An illustrative example is presented for the production of corrugated board with different effluents, demonstrating the importance of considering quality, process effluents and the difference between the modeling approaches.
A clinical trial was conducted to test a new protocol of normal muscle precursor cell (MPC) allotransplantation in skeletal muscles of patients with Duchenne muscular dystrophy (DMD). Cultured MPCs obtained from one of the patient's parents were implanted in 0.25 or 1 cm of a Tibialis anterior in 9 patients with DMD. MPC injections were placed 1 to 2 mm from each other, and a similar pattern of saline injections was done in the contralateral muscle. The patients were immunosuppressed with tacrolimus. Muscle biopsies were performed at the injected sites 4 weeks later. In the biopsies of the cell-grafted sites, there were myofibers expressing donor's dystrophin in 8 patients. The percentage of myofibers expressing donor's dystrophin varied from 3.5% to 26%. Evidence of small myofiber neoformation was observed in some patients. Donor-derived dystrophin transcripts were detected by reverse transcriptase-polymerase chain reaction in the cell-grafted sites in all patients. The protocol of immunosuppression was sufficient to obtain these results, although it is not certain whether acute rejection was efficiently controlled in all the cases. In conclusion, intramuscular allotransplantation of normal MPCs can induce the expression of donor-derived dystrophin in skeletal muscles of patients with DMD, although this expression is restricted to the sites of MPC injection.
Purpose Freshwater scarcity is a problem in many areas of the world and will become one of the most sensitive environmental issues in coming decades. Existing life cycle assessment (LCA) methodologies generally do not provide assessment schemes or characterization factors of the potential environmental impacts of freshwater use or freshwater resource depletion. These assessments therefore do not account for the significant environmental consequences of the loss in quality and availability of freshwater. This paper aims to develop a framework to address this methodological limitation and to support further quantitative modeling of the cause-effect chain relationships of water use. The framework includes recommendations for life cycle inventory (LCI) modeling and provides a description of possible impact pathways for life cycle impact assessment (LCIA), including indicators on midpoint and endpoint levels that reflect different areas of protection (AoP).Methodology LCI of freshwater use aims to quantify changes in freshwater availability. The key elements affected by changes in availability are sufficient freshwater supplies for contemporary human users, ecosystems, and future generations, the latter referring to the renewability of the resource. Three midpoint categories are therefore proposed and linked to common AoP as applied in LCIA. Results and discussion We defined a set of water types, each representing an elementary flow. Water balances for each type allows the quantification of changes in freshwater availability. These values are recommended as results for the LCI of water use. Insufficient freshwater supplies for contemporary human users can mean freshwater deficits for human uses, which is the first midpoint impact category ultimately affecting the AoP of human life; freshwater deficits in ecosystems is the second proposed midpoint impact category and is linked to the AoP biotic environment. Finally, the last midpoint category is freshwater depletion caused by intensive overuse that exceeds the regeneration rate, which itself is ultimately linked to the AoP abiotic environment. Depending on the regional context, the development of scenarios aimed to compensate for the lack of water for specific uses by using backup technologies (e.g., saltwater treatment, the import of agricultural goods) can avoid generating direct impacts on the midpoint impact category freshwater deficits for human uses. Indirect impacts must be assessed through an extension of system boundaries including these backup technologies. Because freshwater is a resource with high spatial and temporal variability, the proposed framework discusses aspects of regionalization in relationship to data availability, appropriate spatial and temporal resolution, and software capacities to support calculations. Conclusions
Three Duchenne muscular dystrophy (DMD) patients received injections of myogenic cells obtained from skeletal muscle biopsies of normal donors. The cells (30 x 10 (6)) were injected in 1 cm3 of the tibialis anterior by 25 parallel injections. We performed similar patterns of saline injections in the contralateral muscles as controls. The patients received tacrolimus for immunosuppression. Muscle biopsies were performed at the injected sites 4 weeks later. We observed dystrophin-positive myofibers in the cell-grafted sites amounting to 9 (patient 1), 6.8 (patient 2), and 11% (patient 3). Since patients 1 and 2 had identified dystrophin-gene deletions these results were obtained using monoclonal antibodies specific to epitopes coded by the deleted exons. Donor dystrophin was absent in the control sites. Patient 3 had exon duplication and thus specific donor-dystrophin detection was not possible. However, there were fourfold more dystrophin-positive myofibers in the cell-grafted than in the control site. Donor-dystrophin transcripts were detected by RT-PCR (using primers reacting with a sequence int eh deleted exons) only in the cell-grafted sites in patients 1 and 2. Dystrophin transcripts were more abundant in the cell-grafted than in the control site in patient 3. Therefore, significant dystrophin expression can be obtained in teh skeletal muscles of DMD patients following specific conditions of cell delivery and immunosuppression.
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