Identifying best existing practice for characterization modeling in life cycle impact assessment

Purpose

Life cycle impact assessment (LCIA) is a field of active development. The last decade has seen prolific publication of new impact assessment methods covering many different impact categories and providing characterization factors that often deviate from each other for the same substance and impact. The LCA standard ISO 14044 is rather general and unspecific in its requirements and offers little help to the LCA practitioner who needs to make a choice. With the aim to identify the best among existing characterization models and provide recommendations to the LCA practitioner, a study was performed for the Joint Research Centre of the European Commission (JRC).

Methods

Existing LCIA methods were collected and their individual characterization models identified at both midpoint and endpoint levels and supplemented with other environmental models of potential use for LCIA. No new developments of characterization models or factors were done in the project. From a total of 156 models, 91 were short listed as possible candidates for a recommendation within their impact category. Criteria were developed for analyzing the models within each impact category. The criteria addressed both scientific qualities and stakeholder acceptance. The criteria were reviewed by external experts and stakeholders and applied in a comprehensive analysis of the short-listed characterization models (the total number of criteria varied between 35 and 50 per impact category). For each impact category, the analysis concluded with identification of the best among the existing characterization models. If the identified model was of sufficient quality, it was recommended by the JRC. Analysis and recommendation process involved hearing of both scientific experts and stakeholders.

Results and recommendations

Recommendations were developed for 14 impact categories at midpoint level, and among these recommendations, three were classified as “satisfactory” while ten were “in need of some improvements” and one was so weak that it has “to be applied with caution.” For some of the impact categories, the classification of the recommended model varied with the type of substance. At endpoint level, recommendations were only found relevant for three impact categories. For the rest, the quality of the existing methods was too weak, and the methods that came out best in the analysis were classified as “interim,” i.e., not recommended by the JRC but suitable to provide an initial basis for further development.

Discussion, conclusions, and outlook

The level of characterization modeling at midpoint level has improved considerably over the last decade and now also considers important aspects like geographical differentiation and combination of midpoint and endpoint characterization, although the latter is in clear need for further development. With the realization of the potential importance of geographical differentiation comes the need for characterization models that are able to produce characterization factors that are representative for different continents and still support aggregation of impact scores over the whole life cycle. For the impact categories human toxicity and ecotoxicity, we are now able to recommend a model, but the number of chemical substances in common use is so high that there is a need to address the substance data shortage and calculate characterization factors for many new substances. Another unresolved issue is the need for quantitative information about the uncertainties that accompany the characterization factors. This is still only adequately addressed for one or two impact categories at midpoint, and this should be a focus point in future research. The dynamic character of LCIA research means that what is best practice will change quickly in time. The characterization methods presented in this paper represent what was best practice in 2008–2009.     

The influence of value choices in life cycle impact assessment of stressors causing human health damage

Purpose

This study analyzes the influence of value choices in impact assessment models for human health, such as the choice of time horizon, on life cycle assessment outcomes.

Methods

For 756 products, the human health damage score is calculated using three sets of characterization factors (CFs). The CFs represent seven human health impact assessment categories: water scarcity, tropospheric ozone formation, particulate matter formation, human toxicity, ionizing radiation, stratospheric ozone depletion, and climate change. Each set of CFs embeds a combination of value choices following the Cultural Theory, and reflects the individualist, hierarchist, or egalitarian perspective.

Results

We found that the average difference in human health damage score goes from 1 order of magnitude between the individualist and hierarchist perspectives to 2.5 orders of magnitude between the individualist and egalitarian perspectives. The difference in damage score of individual materials among perspectives depends on the combination of emissions driving the impact of both perspectives and can rise up to 5 orders of magnitude.

Conclusions

The value choices mainly responsible for the differences in results among perspectives are the choice of time horizon and inclusion of highly uncertain effects. A product comparison can be affected when the human health damage score of two products differ less than a factor of 5, or the comparing products largely differ in their emitted substances. Overall, our study implies that value choices in impact assessment modeling can modify the outcomes of a life cycle assessment (LCA) and thus the practical implication of decisions based on the results of an LCA.     

Lactosylceramide induced by elastin-derived peptides decreases adipocyte differentiation

Journal of Physiology and Biochemistry - Elastin, the major protein of the extracellular matrix, is specially found in cardiovascular tissues and contributing to 30–50% of the dry weight of...     

Simplification of the enameloid microstructure of large stingrays (Chondrichthyes: Myliobatiformes): a functional approach

The microstructure of neoselachian teeth is characterized by a triple‐layered enameloid, despite its purported absence in batoids since their appearance during the early Jurassic. This feature is thought to have been secondarily lost, as an adaptation to durophagy in batoids. The monophyletic Myliobatiformes are an ecologically diverse clade of batoids that includes very specialized taxa such as the filter‐feeding mobulids and the durophagous myliobatids. Their diversity and recent evolutionary history (Palaeogene) make them an ideal model for assessing adaptive constraints that influence enameloid microstructure. This first study focusing only on batoid enameloid shows a very reduced single‐layered enameloid in the derived filter feeders. However, most other taxa show a double‐layered enameloid, which is probably plesiomorphic for batoids. It is concluded that the triple‐layered enameloid is not a synapomorphy of the neoselachii as a whole, but of Selachimorpha only, and that diet specialization in derived myliobatoids indeeds impact their enameloid microctructure, which is confirmed by their fossil diversity. © 2013 The Linnean Society of London     

ER-mitochondria signaling regulates autophagy

The endoplasmic reticulum (ER) and mitochondria form tight functional contacts that regulate several key cellular processes. The formation of these contacts involves “tethering proteins” that function to recruit regions of ER to mitochondria. The integral ER protein VAPB (VAMP associated protein B and C) binds to the outer mitochondrial membrane protein, RMDN3/PTPIP51 (regulator of microtubule dynamics 3) to form one such set of tethers. Recently, we showed that the VAPB-RMDN3 tethers regulate macroautophagy/autophagy. Small interfering RNA (siRNA) knockdown of VAPB or RMDN3 to loosen ER-mitochondria contacts stimulates autophagosome formation, whereas overexpression of VAPB or RMDN3 to tighten contacts inhibit their formation. Artificial tethering of ER and mitochondria via expression of a synthetic linker protein also reduces autophagy and this artificial tether rescues the effects of VAPB- or RMDN3-targeted siRNA loss on autophagosome formation. Finally, our studies revealed that the modulatory effects of ER-mitochondria contacts on autophagy involve their role in mediating ITPR (inositol 1,4,5-trisphosphate receptor) delivery of Ca²⁺ from ER stores to mitochondria.     

Fifteen years of Servitude et Grandeur to the application of a biophysical technique in medicine: The tale of AFMBioMed

AFMBioMed is the founding name under which international conferences and summer schools are organized around the application of atomic force microscopy in life sciences and nanomedicine. From its inception at the Atomic Energy Commission in Marcoule near 2004 to its creation in 2007 and to its 10th anniversary conference in Krakow, a brief narrative history of its birth and rise will demonstrate how and what such an organization brings to laboratories and the AFM community. With the current planning of the next AFMBioMed conference in Münster in 2019, it will be 15 years of commitment to these events.     

Anhydrobiosis: Inside yeast cells

Under natural conditions yeast cells as well as other microorganisms are regularly subjected to the influence of severe drought, which leads to their serious dehydration. The dry seasons are then changed by rains and there is a restoration of normal water potential inside the cells. To survive such seasonal changes a lot of vegetative microbial cells, which belong to various genera and species, may be able to enter into a state of anhydrobiosis, in which their metabolism is temporarily and reversibly suspended or delayed. This evolutionarily developed adaptation to extreme conditions of the environment is widely used for practical goals – for conservation of microorganisms in collections, for maintenance and long storage of different important strain-producers and for other various biotechnological purposes. This current review presents the most important data obtained mainly in the studies of the structural and functional changes in yeast cells during dehydration. It describes the changes of the main organelles of eukaryotic cells and their role in cell survival in a dry state. The review provides information regarding the role of water in the structure and functions of biological macromolecules and membranes. Some important intracellular protective reactions of eukaryotic organisms, which were revealed in these studies and may have more general importance, are also discussed. The results of the studies of yeast anhydrobiosis summarized in the review show the possibilities of improving the conservation and long-term storage of various microorganisms and of increasing the quality of industrially produced dry microbial preparations.