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51.
Purpose

The novelty of the O-LCA method and the existing differences with the established product LCA practice, as well as the unique structure each organization, pose a broad range of methodological and application challenges, in addition to the general methodological gaps in LCA. In order to provide practitioners with lessons learned for future applications and boost future method development efforts, the paper discusses those challenges.

Methods

The challenges included in this paper were mainly identified from a survey administered to the road testers and from experiences during the piloting process. These are complemented with case studies from literature. The focus of the paper is on challenges exclusive to the organizational approach, although some additional issues common to product LCA but intensified in organizational LCA are also included. Each issue is characterized and exemplified, recommendations of reference standards are analyzed, and possible solutions discussed.

Results and discussion

With the goal and scope of O-LCA, some challenging issues were to select part of an organization as the reporting organization, and the operability of the reporting flow. Regarding the system boundary, the challenges were which parts of the supply chain should be included in the study, problems when setting the system boundary for the service sector, how to include supporting activities, and how to prepare the right system boundary diagrams. Regarding the inventory stage, the discussion starts with alternatives to the categorization of the inventory into activities and the aggregation of those activities into groups. It includes an equivalence table for an easier transfer from other organizational frameworks (ISO 14069 and the GHG Protocol). Some challenges during impact assessment and interpretation were the assessment of local impacts, scoping performance tracking, and the use of O-LCA results for an organization’s strategy.

Conclusions

The review of challenges is not meant as a complete overview of all possible challenges—new challenges may arise in future case studies. Further application testing is needed, along with research to support a future revision of the O-LCA Guidance, in line with the issues highlighted in this paper and new challenges may arise in future case studies. O-LCA has the potential to contribute in the future implementation of the life cycle concept in environmental management systems, in the development of organizational footprint metrics for region-specific impacts, and in the social dimension of life cycle assessment.

  相似文献   
52.
Purpose

Ferro niobium (FeNb) is a metallic alloy whose industrial use has been increasing steadily in the last decades. This work aims to systematize the available information on FeNb production, provide its inventory data and generate its first technologically representative publicly available life cycle impact assessment (LCIA).

Methods

The production of 1 kg of FeNb from pyrochlore in the baseline year 2017 was modelled following a cradle-to-gate approach. Primary information on mass, energy and water flows was collected when possible from the Brazilian leading FeNb supplier, CBMM (80% of the world market). The CML method (CML-IA 4.7) was applied for the impact assessment including global warming potential (GWP), acidification potential (AP), eutrophication potential (EP), ozone layer depletion potential (ODP), abiotic depletion potential (fossil and elemental) (ADPfossil and ADPelemental) and photochemical ozone creation potential (POCP).

Results and discussion

The first stage of pyrochlore processing (pyrochlore ore extraction, mechanical processing and flotation) and the last stage (aluminothermic reaction) bear the highest impact in all analyzed CML impact categories. The primary aluminium consumption has the most important contribution in five out of seven impact categories (50% in ADPfossil, 55% in AP, 35% in EP, 57% in GWP and 40% in POCP). In this sense, the industry should promote a higher share of secondary aluminium in the production process. Also, the impact from electricity consumption and processing chemicals showed to be relevant.

Conclusions

This work is the first LCIA on ferro niobium to be published with representative, high-quality data. A dataset was produced in order to enable ferro niobium to be incorporated to future LCIA-modelling.

  相似文献   
53.
The International Journal of Life Cycle Assessment - This paper proposes a practical methodological approach to assess the water footprint at the organizational level, in line with the current...  相似文献   
54.
Treatment options for people living with amyotrophic lateral sclerosis (ALS) are limited and ineffective. Recently, dexpramipexole (RPPX) was advanced into human ALS clinical trials. In the current studies, we investigated RPPX in two parallel screening systems: 1) appropriately powered, sibling-matched, gender-balanced survival efficacy screening in high-copy B6-SJL-SOD1G93A/Gur1 mice, and 2) high-content neuronal survival screening in primary rat cortical neurons transfected with wild-type human TDP43 or mutant human TDP43. In both cases, we exposed the test systems to RPPX levels approximating those achieved in human Phase II clinical investigations. In SOD1G93A mice, no effect was observed on neuromotor disease progression or survival. In primary cortical neurons transfected with either mutant or wild-type human TDP43, a marginally significant improvement in a single indicator of neuronal survival was observed, and only at the 10 µM RPPX treatment. These systems reflect both mutant SOD1- and TDP43-mediated forms of neurodegeneration. The systems also reflect both complex non-cell autonomous and neuronal cell autonomous disease mechanisms. The results of these experiments, taken in context with results produced by other molecules tested in both screening systems, do not argue positively for further study of RPPX in ALS.  相似文献   
55.
In the search for neuroprotective factors in Huntington's disease, we found that insulin growth factor 1 via activation of the serine/threonine kinase Akt/PKB is able to inhibit neuronal death specifically induced by mutant huntingtin containing an expanded polyglutamine stretch. The IGF-1/Akt pathway has a dual effect on huntingtin-induced toxicity, since activation of this pathway also results in a decrease in the formation of intranuclear inclusions of mutant huntingtin. We demonstrate that huntingtin is a substrate of Akt and that phosphorylation of huntingtin by Akt is crucial to mediate the neuroprotective effects of IGF-1. Finally, we show that Akt is altered in Huntington's disease patients. Taken together, these results support a potential role of the Akt pathway in Huntington's disease.  相似文献   
56.

Purpose

End-of-life (EoL) modelling in life cycle assessment has already been broadly discussed within several studies. However, no consensus has been achieved on how to model recycling in LCA, even though several approaches have been developed. Within this paper, results arising from the application of two new EoL formulas, the product environmental footprint (PEF) and the multi-recycling-approach (MRA) ones, are compared and discussed. Both formulas consider multiple EoL scenarios such as recycling, incineration and landfill.

Methods

The PEF formula has been developed within the PEF programme whose intent is to define a harmonized methodology to evaluate the environmental performance of products. The formula is based on a 50:50 allocation approach, as burdens and benefits associated with recycling are accounted for a 50% rate. The MRA formula has been developed to change focus from products to materials. Recycling cycles and material losses over time are considered with reference to material pools. Allocation between systems is no longer needed, as the actual number of potential life cycles for a certain material is included in the calculation. Both the approaches have been tested within two case studies.

Results and discussion

Methodological differences could thereof be determined, as well as applicability concerns, due to the type of data required for each formula. As far as the environmental performance is concerned, impacts delivered by MRA are lower than those delivered by PEF for aluminium, while the opposite happens for plastic and rubber due to the higher share of energy recovery accounted in PEF formula. Stainless steel impacts are almost the same.

Conclusions and recommendations

The application of the two formulas provides some inputs for the EoL dilemma in LCA. The use of a wider perspective, better reflecting material properties all over the material life cycle, is of substantial importance to properly represent recycling situations. In MRA, such properties are treated and less data are required compared to the PEF formula. On the contrary, the PEF model better accommodates the modelling of products whose materials, at end of life, can undertake the route of recycling or recovery (or landfill), depending on country-specific EoL management practices. However, its application requires more data.
  相似文献   
57.
S Finkbeiner 《Neuron》1992,8(6):1101-1108
Stimulus-evoked cellular responses are sometimes organized in the form of propagating waves of cytoplasmic Ca2+ increase. Ca2+ waves can be elicited in cultured astrocytes by the neurotransmitter glutamate; however, the propagation mechanism is unknown. Here, qualitative and quantitative features of propagation suggest that astrocytic Ca2+ waves are mediated by an intracellular signal that crosses intercellular junctions. The role of gap junctions in cell-cell Ca2+ wave propagation was specifically tested. Functional gap junctions were demonstrated using a noninvasive fluorescence recovery method and the gap junction blockers halothane and octanol. Gap junction closure prevented intracellular waves from propagating between cells without affecting the velocity of the intracellular wave itself. The pivotal role played by the gap junction creates the potential for dynamic changes in glial connectivity and long-range glial signaling.  相似文献   
58.
We have developed a technique for expanding primary cultures of human tracheal epithelium while minimizing loss of differentiated structure and function. Cells were seeded at 2 x 10(4) cells/cm2 into T75 flasks and trypsinized when approximately 80% confluent. The dispersed cells were then passaged at the same plating density into further T75 flasks or seeded at 5 x 10(5) cells/cm2 on porous-bottomed inserts and maintained with an air-interface. Differentiation of cells on inserts was assessed from transepithelial electrical resistance (an index of tight junction formation), short-circuit current (an index of transepithelial salt transport), cell numbers, total cell protein, and histology. Unpassaged cells (P0) and cells passaged once (P1) took about a week to become 80% confluent on T75 flasks, with 10-fold and 5-fold increases in cell numbers, respectively. Confluence was achieved in approximately 3 days following plating to inserts. Functionally and structurally, P1 and P2 cells (cells passaged twice) were little different from P0 cells. Thus, within a little over 2 weeks, the numbers of confluent cell sheets can be increased 50-fold with minimal change in function. However, there was a marked decline in differentiation by cells passaged three times (P3), and not all cell preparations could be taken to P4 (cells passaged four times).  相似文献   
59.
The swallowtail butterfly Papilio polytes is known for its striking resemblance in wing pattern to the toxic butterfly Pachliopta aristolochiae and is a focal system for the study of mimicry evolution. Papilio polytes females are polymorphic in wing pattern, with mimetic and nonmimetic forms, while males are monomorphic and nonmimetic. Past work invokes selection for mimicry as the driving force behind wing pattern evolution in P. polytes. However, the mimetic relationship between P. polytes and P. aristolochiae is not well understood. In order to test the mimicry hypothesis, we constructed paper replicas of mimetic and nonmimetic P. polytes and P. aristolochiae, placed them in their natural habitat, and measured bird predation on replicas. In initial trials with stationary replicas and plasticine bodies, overall predation was low and we found no differences in predation between replica types. In later trials with replicas mounted on springs and with live mealworms standing in for the butterfly's body, we found less predation on mimetic P. polytes replicas compared to nonmimetic P. polytes replicas, consistent with the predator avoidance benefits of mimicry. While our results are mixed, they generally lend support to the mimicry hypothesis as well as the idea that behavioral differences between the sexes contributed to the evolution of sexually dimorphic mimicry.  相似文献   
60.
Digoxigenin-labeled riboprobes of six groups of human mucins were evaluated for sensitivity in archival tissue, using protease XXIV or proteinase K during in situ hybridization. (J Histochem Cytochem 49:923-924, 2001)  相似文献   
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