| 1. |
- Bernstad Saraiva Schott, Anna, et al.
(author)
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Identification of decisive factors for greenhouse gas emissions in comparative life cycle assessments of food waste management - An analytical review
- 2016
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In: Journal of Cleaner Production. - : Elsevier BV. - 0959-6526. ; 119, s. 13-24
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Research review (peer-reviewed)abstract
- A review of existing life cycle assessments on food waste management was made with two main aims. Firstly, to make an overview of the assessments of the global warming potential from the treatment alternatives incineration, landfill, anaerobic digestion and compost in studies reported in literature. Secondly, to identify decisive factors in general and related to system boundary settings in particular, in reviewed studies. A number of criteria were constructed for identification of relevant comparative life cycle assessments, resulting in selection of nineteen studies, containing 103 different scenarios. The systematic investigation of the studies show examples of several methodological differences as well as choices in systems boundary setting causing misleading comparisons between different treatment options, but also large variations in used input data for modeling of similar processes. The review also shows that the most significant differences in global warming results in many cases can be explained by assumptions made in relation to the background system, rather than by differences in data on emissions surging from to the foreground system. Especially assumptions on the interaction of the waste management system with the background energy system and/or bio-system were found to be decisive to the results. This highlights the importance of identification of induced and displaced marginal products in the modeling of system expansion, as well as need for increased transparency and use of sensitivity analyses related to assumptions made in background system modeling, in order to reveal under which set of assumptions results gained in the assessment are valid.
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| 2. |
- Carlos-Pinedo, Sandra
(author)
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Renewable Energy and Nutrient Valorization from Anaerobic Digestion : Resource-Efficient Solutions
- 2023
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Doctoral thesis (other academic/artistic)abstract
- This thesis presents a comprehensive analysis aimed at understanding process performance, methane yield, and key influencing factors within the context of solid-state anaerobic digestion (SS-AD). SS-AD is used to treat organic material with high solids content, which can be challenging to address by alternative methods. The investigation involves modelling and simulation exploring mass and energy balances and the associated environmental implications. To achieve this, a waste management tool, ORganic WAste REsearch (ORWARE) was adapted and validated to suit the unique parameters of SS-AD operating under a plug-flow reactor configuration, representing a specific case study. The search of an optimal feedstock mix that enhances the digestion process and energy performance is highlighted. Findings suggest that feedstock selection significantly affects methane yield in SS-AD systems, and optimizing substrate mixtures can enhance process efficiency. Key considerations include biodegradability and lignocellulosic content. Operational parameters, such as temperature variations, impact the results from the model, while responsiveness of hydraulic retention time and organic loading rate remains limited. A further comparison between a liquid anaerobic digestion (L-AD) vs SS-AD is made, despite similar methane yields, SS-AD outperforms due to higher energy turnover. Additionally, effective management of digestate nutrients is crucial for its biofertilizer use. Beyond the biogas system, the thesis explores interconnected relationships between SS-AD inputs and outputs and their subsequent use as resources for a hydroponic greenhouse production system. The examination of system interconnections and their broader implications emphasizes the importance of comprehensive assessments when integrating biogas systems beyond their conventional applications.
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| 3. |
- Gray, Declan, et al.
(author)
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Membrane depolarization kills dormant Bacillus subtilis cells by generating a lethal dose of ROS
- 2024
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In: Nature Communications. - 2041-1723 .- 2041-1723. ; 15:1
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Journal article (peer-reviewed)abstract
- The bactericidal activity of several antibiotics partially relies on the production of reactive oxygen species (ROS), which is generally linked to enhanced respiration and requires the Fenton reaction. Bacterial persister cells, an important cause of recurring infections, are tolerant to these antibiotics because they are in a dormant state. Here, we use Bacillus subtilis cells in stationary phase, as a model system of dormant cells, to show that pharmacological induction of membrane depolarization enhances the antibiotics’ bactericidal activity and also leads to ROS production. However, in contrast to previous studies, this results primarily in production of superoxide radicals and does not require the Fenton reaction. Genetic analyzes indicate that Rieske factor QcrA, the iron-sulfur subunit of respiratory complex III, seems to be a primary source of superoxide radicals. Interestingly, the membrane distribution of QcrA changes upon membrane depolarization, suggesting a dissociation of complex III. Thus, our data reveal an alternative mechanism by which antibiotics can cause lethal ROS levels, and may partially explain why membrane-targeting antibiotics are effective in eliminating persisters.
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| 4. |
- Humphrey, Madeleine, et al.
(author)
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Tracking Global and Local Changes in Membrane Fluidity Through Fluorescence Spectroscopy and Microscopy
- 2023
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In: Methods in Molecular Biology. - New York, NY : Springer US. - 1940-6029 .- 1064-3745. ; 2601, s. 203-229
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Book chapter (other academic/artistic)abstract
- Membrane fluidity is a critical parameter of cellular membranes, which cells continuously strive to maintain within a viable range. Interference with the correct membrane fluidity state can strongly inhibit cell function. Triggered changes in membrane fluidity and associated impacts on lipid domains have been postulated to contribute to the mechanism of action of membrane targeting antimicrobials, but the corresponding analyses have been hampered by the absence of readily available analytical tools. Here, we expand upon the protocols outlined in the first edition of this book, providing further and alternative protocols that can be used to measure changes in membrane fluidity. We provide detailed protocols, which allow straightforward in vivo and in vitro measurement of antibiotic compound-triggered changes in membrane fluidity and fluid membrane microdomains. Furthermore, we summarize useful strains constructed by us and others to characterize and confirm lipid specificity of membrane antimicrobials directly in vivo.
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| 5. |
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| 6. |
- Wenzel, Ulf Alexander, 1975, et al.
(author)
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Spontaneous colitis in Muc2-deficient mice reflects clinical and cellular features of active ulcerative colitis.
- 2014
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In: PloS one. - : Public Library of Science (PLoS). - 1932-6203. ; 9:6
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Journal article (peer-reviewed)abstract
- The colonic mucus layer plays a critical role in intestinal homeostasis by limiting contact between luminal bacteria and the mucosal immune system. A defective mucus barrier in animal models allows bacterial contact with the intestinal epithelium and results in spontaneous colitis. A defective mucus barrier is also a key feature of active ulcerative colitis (UC). Alterations in the immune compartment due to intestinal bacterial breach in mice lacking the colon mucus barrier have not been characterized and correlated to active UC.
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