| 1. |
- Munthe, Christian, 1962
(författare)
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Precaution and Ethics: Handling risks, uncertainties and knowledge gaps in the regulation of new biotechnologies
- 2017
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- This volume outlines and analyses ethical issues actualized by applying a precautionary approach to the regulation of new biotechnologies. It presents a novel way of categorizing and comparing biotechnologies from a precautionary standpoint. Based on this, it addresses underlying philosophical problems regarding the ethical assessment of decision-making under uncertainty and ignorance, and discusses how risks and possible benefits of such technologies should be balanced from an ethical standpoint. It argues on conceptual and ethical grounds for a technology neutral regulation as well as for a regulation that not only checks new technologies but also requires old, inferior ones to be phased out. It demonstrates how difficult ethical issues regarding the extent and ambition of precautionary policies need to be handled by such a regulation, and presents an overarching framework for doing so.
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| 2. |
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| 3. |
- Sanli, Kemal, et al.
(författare)
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Metagenomic Sequencing of Marine Periphyton: Taxonomic and Functional Insights into Biofilm Communities
- 2015
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Ingår i: Frontiers in Microbiology. - : Frontiers Media SA. - 1664-302X. ; 6:1192
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Tidskriftsartikel (refereegranskat)abstract
- Periphyton communities are complex phototrophic, multispecies biofilms that develop on surfaces in aquatic environments. These communities harbor a large diversity of organisms comprising viruses, bacteria, algae, fungi, protozoans and metazoans. However, thus far the total biodiversity of periphyton has not been described. In this study, we use metagenomics to characterize periphyton communities from the marine environment of the Swedish west coast. Although we found approximately ten times more eukaryotic rRNA marker gene sequences compared to prokaryotic, the whole metagenome-based similarity searches showed that bacteria constitute the most abundant phyla in these biofilms. We show that marine periphyton encompass a range of heterotrophic and phototrophic organisms. Heterotrophic bacteria, including the majority of proteobacterial clades and Bacteroidetes, and eukaryotic macro-invertebrates were found to dominate periphyton. The phototrophic groups comprise Cyanobacteria and the alpha-proteobacterial genus Roseobacter, followed by different micro- and macro-algae. We also assess the metabolic pathways that predispose these communities to an attached lifestyle. Functional indicators of the biofilm form of life in periphyton involve genes coding for enzymes that catalyze the production and degradation of extracellular polymeric substances, mainly in the form of complex sugars such as starch and glycogen-like meshes together with chitin. Genes for 278 different transporter proteins were detected in the metagenome, constituting the most abundant protein complexes. Finally, genes encoding enzymes that participate in anaerobic pathways, such as denitrification and methanogenesis, were detected suggesting the presence of anaerobic or low-oxygen micro-zones within the biofilms.
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| 4. |
- Munthe, Christian, 1962
(författare)
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The Price of Precaution and the Ethics of Risk
- 2011
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- Since a couple of decades, the notion of a precautionary principle plays a central and increasingly influential role in international as well as national policy and regulation regarding the environment and the use of technology. Urging society to take action in the face of potential risks of human activities in these areas, the recent focus on climate change has further sharpened the importance of this idea. However, the idea of a precautionary principle has also been problematised and criticised by scientists, scholars and policy activists, and been accused of almost every intellectual sin imaginable: unclarity, impracticality, arbitrariness and moral as well as political unsoundness. In that light, the very idea of precaution as an ideal for policy making rather comes out as a dead end. On the basis of these contrasting starting points, Christian Munthe undertakes an innovative, in-depth philosophical analysis of what the idea of a precautionary principle is and should be about. A novel theory of the ethics of imposing risks is developed and used as a foundation for defending the idea of precaution in environmental and technological policy making against its critics, while at the same time avoiding a number of identified flaws. The theory is shown to have far-reaching consequences for areas such as bio-, information- and nuclear technology, and global environmental policy in areas such as climate change. The author argues that, while the price we pay for precaution must not be too high, we have to be prepared to pay it in order to act ethically defensible. A number of practical suggestions for precautionary regulation and policy making are made on the basis of this, and some challenges to basic ethical theory as well as consumerist societies, the global political order and liberal democracy are identified
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| 5. |
- Cutas, Daniela, 1978, et al.
(författare)
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Legal imperialism in the regulation of stem cell research and therapy: the problem of extraterritorial jurisdiction
- 2010
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Ingår i: Capps BJ & Campbell AV (eds.). CONTESTED CELLS: Global Perspectives on the Stem Cell Debate. - London : Imperial College Press. - 9781848164376 ; , s. 95-119
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Countries worldwide have very different national regulations on human embryonic stem (ES) cell research, informed by a range of ethical values. Some countries find reason to extend the applicability of their regulations on such research to its citizens when they visit other countries. Extraterritorial jurisdiction has recently been identified as a potential challenge towards global regulation of ES cell research. This chapter explores the implications and impact of extraterritorial jurisdiction and global regulation of ES cell research on researchers, clinicians and national health systems, and how this may affect patients. The authors argue that it would make ethical sense for ES cell restrictive countries to extend its regulations on ES cell research beyond its borders, because, if these countries really consider embryo destruction to be objectionable on the basis on the status of the embryo, then they ought to count it morally on par with murder (and thus have a moral imperative to protect embryos from the actions of its own citizens). However, doing so could lead to a legal situation that would result in substantial harm to central values in areas besides research, such as health care, the job market, basic freedom of movement, and strategic international finance and politics. Thus, it seems that restrictive extraterritorial jurisdiction in respect to ES cell research would be deeply problematic, given that the ethical permissibility of ES cell research is characterised by deep and wide disagreement.
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| 6. |
- Munthe, Christian, 1962, et al.
(författare)
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The Return of Lombroso? Ethical Aspects of (Visions of) Preventive Forensic Screening
- 2015
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Ingår i: Public Health Ethics. - : Oxford University Press (OUP). - 1754-9973 .- 1754-9981. ; 8:3, s. 270-283
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Tidskriftsartikel (refereegranskat)abstract
- The vision of legendary criminologist Cesare Lombroso to use scientific theories of individual causes of crime as a basis for screening and prevention programmes targeting individuals at risk for future criminal behaviour has resurfaced, following advances in genetics, neuroscience and psychiatric epidemiology. This article analyses this idea and maps its ethical implications from a public health ethical standpoint. Twenty-seven variants of the new Lombrosian vision of forensic screening and prevention are distinguished, and some scientific and technical limitations are noted. Some lures, biases and structural factors, making the application of the Lombrosian idea likely in spite of weak evidence are pointed out and noted as a specific type of ethical aspect. Many classic and complex ethical challenges for health screening programmes are shown to apply to the identified variants and the choice between them, albeit with peculiar and often provoking variations. These variations are shown to actualize an underlying theoretical conundrum in need of further study, pertaining to the relationship between public health ethics and the ethics and values of criminal law policy.
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| 7. |
- Rämö, Robert, et al.
(författare)
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Sediment Remediation Using Activated Carbon: Effects of Sorbent Particle Size and Resuspension on Sequestration of Metals and Organic Contaminants.
- 2022
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Ingår i: Environmental toxicology and chemistry. - : Wiley. - 1552-8618 .- 0730-7268. ; 41:4, s. 1096-1110
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Tidskriftsartikel (refereegranskat)abstract
- Thin-layer capping using activated carbon (AC) has been described as a cost-effective in situ sediment remediation method for organic contaminants. In this study, we compare the capping efficiency of powdered AC (PAC) against granular AC (GAC) using contaminated sediment from Oskarshamn harbor, Sweden. The effects of resuspension on contaminant retention and cap integrity were also studied. Intact sediment cores were collected from the outer harbor and brought to the laboratory. Three thin-layer caps, consisting of PAC or GAC mixed with clay, or clay only, were added to the sediment surface. Resuspension was created using a motor-driven paddle to simulate propeller wash from ship traffic. Passive samplers were placed in the sediment and in the water column to measure the sediment-to-water release of PAHs, PCBs, and metals. Our results show that a thin-layer cap with PAC reduced sediment-to-water fluxes of PCBs by 57 % under static conditions and 91 % under resuspension. Thin-layer capping with GAC was less effective than PAC, but reduced fluxes of high-molecular weight PAHs. Thin-layer capping with AC was less effective in retaining metals, except for Cd, which release was significantly reduced by PAC. Resuspension generally decreased water concentrations of dissolved cationic metals, perhaps due to sorption to suspended sediment particles. Sediment resuspension in treatments without capping increased fluxes of PCBs with log Kow > 7 and PAHs with log Kow 5 6, but resuspension reduced PCB and PAH fluxes through the PAC thin-layer cap. Overall, PAC performed better than GAC, but adverse effects on the benthic community and transport of PAC to non-target areas are drawbacks that favor the use of GAC. This article is protected by copyright. All rights reserved.© 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.
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| 8. |
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| 9. |
- Petersson, Jesper, 1974
(författare)
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Blurring the shoreline: De- and re-infrastructuring and the changing colors of European flood policy
- 2021
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Ingår i: Environment and Planning E: Nature and Space. - : SAGE Publications. - 2514-8494 .- 2514-8494 .- 2514-8486. ; 4:2, s. 623-644
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Tidskriftsartikel (refereegranskat)abstract
- This paper provides a genealogy of the emergence of a common EU flood policy, including the scope and direction of this policy. Noticing how EU policy proposes green infrastructure (associated with using nature as a buffer zone in managing floods) as an alternative to grey infrastructure (implying fixed installations of concrete and cement), this paper adopts the theoretical lens of the so-called infrastructural turn, which advocates a relational investigation of infrastructure. By engaging this approach, the paper shows how flood infrastructure can contain very different compositions of (unruly) water and (settled) land. A narrative of a historically strong focus on guarding society from the powerful forces of nature through a fixed line of defense is increasingly giving way to more muddy states—quite literally—where society is expected to learn to live with flooding and show ecological consideration. To capture the EU’s, and especially the European Commission’s efforts to establish a pan-European flood infrastructure that accommodates this turn, the concepts of de- and re-infrastructuring are developed. These concepts act as heuristic devices to capture how policy performs some combinations between water and land as constituting an attractive and functional flood infrastructure, but constitutes other infrastructural relations of the aquatic and the terrestrial as undesirable and, hence, as malfunctioning. This performative act of distinguishing between what constitutes “good and proper” versus “bad and undesirable” infrastructure is referred to as a politics of infrastructure.
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| 10. |
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| 11. |
- Checinska, Aleksandra, et al.
(författare)
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Microbiomes of the dust particles collected from the International Space Station and Spacecraft Assembly Facilities
- 2015
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Ingår i: Microbiome. - : Springer Science and Business Media LLC. - 2049-2618. ; 3
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Tidskriftsartikel (refereegranskat)abstract
- Background - The International Space Station (ISS) is a unique built environment due to the effects of microgravity, space radiation, elevated carbon dioxide levels, and especially continuous human habitation. Understanding the composition of the ISS microbial community will facilitate further development of safety and maintenance practices. The primary goal of this study was to characterize the viable microbiome of the ISS-built environment. A second objective was to determine if the built environments of Earth-based cleanrooms associated with space exploration are an appropriate model of the ISS environment. Results - Samples collected from the ISS and two cleanrooms at the Jet Propulsion Laboratory (JPL, Pasadena, CA) were analyzed by traditional cultivation, adenosine triphosphate (ATP), and propidium monoazide–quantitative polymerase chain reaction (PMA-qPCR) assays to estimate viable microbial populations. The 16S rRNA gene Illumina iTag sequencing was used to elucidate microbial diversity and explore differences between ISS and cleanroom microbiomes. Statistical analyses showed that members of the phyla Actinobacteria, Firmicutes, and Proteobacteria were dominant in the samples examined but varied in abundance. Actinobacteria were predominant in the ISS samples whereas Proteobacteria, least abundant in the ISS, dominated in the cleanroom samples. The viable bacterial populations seen by PMA treatment were greatly decreased. However, the treatment did not appear to have an effect on the bacterial composition (diversity) associated with each sampling site. Conclusions - The results of this study provide strong evidence that specific human skin-associated microorganisms make a substantial contribution to the ISS microbiome, which is not the case in Earth-based cleanrooms. For example, Corynebacterium and Propionibacterium (Actinobacteria) but not Staphylococcus (Firmicutes) species are dominant on the ISS in terms of viable and total bacterial community composition. The results obtained will facilitate future studies to determine how stable the ISS environment is over time. The present results also demonstrate the value of measuring viable cell diversity and population size at any sampling site. This information can be used to identify sites that can be targeted for more stringent cleaning. Finally, the results will allow comparisons with other built sites and facilitate future improvements on the ISS that will ensure astronaut health.
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| 12. |
- Beier, Ulrika, et al.
(författare)
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Fisk och fiske i Mälaren
- 2015
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Rapport (populärvet., debatt m.m.)abstract
- Nära en tredjedel av Sveriges befolkning bor i Mälardalen. Mälaren är Sveriges tredje största sjö och en av de artrikaste beträffande fisk. Sjön är både flikig och mångsidig. Ömsom kantas den av slätter med intensivt jordbruk och stora vassområden, ömsom av karga klippor och grusstränder. Här finns omväxlande små och stora öar, grunda vikar, trånga sund och stora, djupa fjärdar. Mälaren har förorenats under århundraden och är fortfarande delvis övergödd. Trots det tjänar den som landets största dricksvattentäkt. Två miljoner människor får dricksvatten från Mälaren. Länge har fokus varit på sjöns vattenkvalitet, både för att dricka och bada i. Mälaren är också viktig som fiskesjö. Fiske i Mälaren innebär oftast rekreation men sjön försörjer också cirka trettio yrkesfiskare. Sist men inte minst - fisken i Mälaren är en viktig del i dess ekosystem. Genom näringsväven återkopplar fisken oundvikligen till vattnets kvalitet. I den här rapporten vill vi sätta Mälarens fisk i fokus. Vi ska berätta om fiskarter som är viktiga för ekosystemet och fisket samt om hur fisken i Mälaren undersöks.
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| 13. |
- Lundqvist, Johan, et al.
(författare)
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Innovative drinking water treatment techniques reduce the disinfection-induced oxidative stress and genotoxic activity
- 2019
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Ingår i: Water Research. - : Elsevier. - 0043-1354 .- 1879-2448. ; 5, s. 182-192
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Tidskriftsartikel (refereegranskat)abstract
- Disinfection of drinking water using chlorine can lead to the formation of genotoxic by-products whenchlorine reacts with natural organic matter (NOM). A vast number of such disinfection by-products(DBPs) have been identified, making it almost impossible to routinely monitor all DBPs with chemicalanalysis. In this study, a bioanalytical approach was used, measuring oxidative stress (Nrf2 activity),genotoxicity (micronucleus test), and aryl hydrocarbon receptor (AhR) activation to evaluate an innovativewater treatment process, including suspended ion exchange, ozonation, in-line coagulation,ceramic microfiltration, and granular activated carbon. Chlorination was performed in laboratory scaleafter each step in the treatment process in order to investigate the effect of each treatment process to theformation of DBPs. Suspended ion exchange had a high capacity to remove dissolved organic carbon(DOC) and to decrease UV absorbance and Nrf2 activity in non-chlorinated water. High-dose chlorination(10 mg Cl2 L-1) of raw water caused a drastic induction of Nrf2 activity, which was decreased by 70% inwater chlorinated after suspended ion exchange. Further reduction of Nrf2 activity following chlorinationwas achieved by ozonation and the concomitant treatment steps. The ozonation treatment resulted indecreased Nrf2 activity in spite of unchanged DOC levels. However, a strong correlation was found betweenUV absorbing compounds and Nrf2 activity, demonstrating that Nrf2 inducing DBPs were formedfrom pre-cursors of a specific NOM fraction, constituted of mainly aromatic compounds. Moreover, highdosechlorination of raw water induced genotoxicity. In similarity to the DOC levels, UV absorbance andNrf2 activity, the disinfection-induced genotoxicity was also reduced by each treatment step of theinnovative water treatment technique. AhR activity was observed in the water produced by the conventionalprocess and in the raw water, but the activity was clearly decreased by the ozonation step inthe innovative water treatment process.
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| 14. |
- Eivazihollagh, Alireza, et al.
(författare)
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On chelating surfactants : Molecular perspectives and application prospects
- 2019
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Ingår i: Journal of Molecular Liquids. - : Elsevier BV. - 0167-7322 .- 1873-3166. ; 278, s. 688-705
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Tidskriftsartikel (refereegranskat)abstract
- Chelating agents, molecules that very strongly coordinates certain metal ions, are used industrially as well as in consumer products to minimize disturbances and increase performance of reactions and applications. The widely used sequestering agents, nitrilotriacetic acid (NTA), ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetic acid (DTPA) belong to this branch of readily water-soluble compounds. When these chemical structures also have hydrophobic parts, they are prone to adsorb at air-water interfaces and to self-assemble. Such bifunctional molecules can be called chelating surfactants and will have more extended utilization prospects than common chelating agents or ordinary ionic surfactants. The present review attempts to highlight the fundamental behavior of chelating surfactants in solution and at interfaces, and their very specific interactions with metal ions. Methods to recover chelating surfactants from metal chelates are also described. Moreover, utilization of chelating surfactants in applications for metal removal in environmental engineering and mineral processing, as well as for metal control in the fields of biology, chemistry and physics, is exemplified and discussed.
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| 15. |
- Munthe, Christian, 1962
(författare)
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A New Ethical Landscape of Prenatal Testing: Individualizing Choice to Serve Autonomy and Promote Public Health: A Radical Proposal
- 2015
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Ingår i: Bioethics. - : Wiley. - 0269-9702 .- 1467-8519. ; 29:1, s. 36-45
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Tidskriftsartikel (refereegranskat)abstract
- A new landscape of prenatal testing (PNT) is presently developing, including new techniques for risk-reducing, non-invasive sampling of foetal DNA and drastically enhanced possibilities of what may be rapidly and precisely analysed, surrounded by a growing commercial genetic testing industry and a general trend of individualization in healthcare policies. This article applies a set of established ethical notions from past debates on PNT for analysing PNT screening-programmes in this new situation. While some basic challenges of PNT stay untouched, the new development supports a radical individualization of how PNT screening is organized. This reformation is, at the same time, difficult to reconcile with responsible spending of resources in a publicly funded healthcare context. Thus, while the ethical imperative of individualization holds and applies to PNT, the new landscape of PNT provides reasons to start rolling back the type of mass-screening programmes currently established in many countries. Instead, more limited offers are suggested, based on considerations of severity of conditions and optimized to simultaneously serve reproductive autonomy and public health within an acceptable frame of priorities. The new landscape of PNT furthermore underscores the ethical importance of supporting and including people with disabilities. For the very same reason, no ban on what may be analysed using PNT in the new landscape should be applied, although private offers must, of course, conform to strict requirements of respecting reproductive autonomy and what that means in terms of counselling.
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| 16. |
- Munthe, Christian, 1962
(författare)
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Precautionary Principle
- 2013
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Ingår i: International Encyclopedia of Ethics. - Chichester : Blackwell. - 9781444367072 ; , s. 4031-4039
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Bokkapitel (refereegranskat)abstract
- Following the statement in the United Nations' Rio Declaration of 1992 that countries should apply a “precautionary approach” in policymaking on environmental and technological issues, the notion of a precautionary principle (PP) has gained ground in worldwide policymaking and regulation, thus catching the interest of ethics scholars. Although seldom explained in much detail, and resulting in quite different policy results in different countries and areas (O'Riordan et al. 2001; Sandin 1999; Trouwborst 2002; Zander 2010), PP is generally understood as a norm urging or permitting policymakers to take preventive action in the face of unknown, uncertain, or probable dangers, motivated by the experience of how seemingly valuable and promising practices may lead to seriously adverse consequences in spite of lack of solid evidence to this effect (Sandin 1999). In ethics debate, this idea has been applied not only to matters regarding the large-scale introduction and use of technology (e.g., regarding energy production, transport and communication, nano- or biotechnology, and so on) (see Biotechnology; Nanotechnology, Ethics of) with possible ensuing impact on the natural environment connecting to the notion of sustainability (see Sustainability), but also, for example, to abortion (see Abortion), medical genetics, embryo experimentation (see Embryo Research), the treatment of animals (see Animal Experimentation), terrorism (see Terrorism), and general research ethics (see Research Ethics) (Munthe 2011). Many of these applications advocate strong conclusions in spite of the fact that PP or its normative justification have not been made very clear. At the same time, PP has been the subject of criticism, much of which boils down to three points: lack of clarity, lack of practicality, and/or ethical implausibility. Curiously, these critical points have often been made in conjunction, in spite of the fact that a clear sense of what PP means seems necessary for backing up the other two objections.
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| 17. |
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| 18. |
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| 19. |
- Åkesson, Sofia, et al.
(författare)
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Characterizing natural degradation of tetrachloroethene (PCE) using a multidisciplinary approach
- 2020
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Ingår i: Ambio: a Journal of the Human Environment. - : Springer Science and Business Media LLC. - 0044-7447 .- 1654-7209. ; 50, s. 1074-1088
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Tidskriftsartikel (refereegranskat)abstract
- A site in mid-western Sweden contaminated with chlorinated solvents originating from a previous dry cleaning facility, was investigated using conventional groundwater analysis combined with compound-specific isotope data of carbon, microbial DNA analysis, and geoelectrical tomography techniques. We show the value of this multidisciplinary approach, as the different results supported each interpretation, and show where natural degradation occurs at the site. The zone where natural degradation occurred was identified in the transition between two geological units, where the change in hydraulic conductivity may have facilitated biofilm formation and microbial activity. This observation was confirmed by all methods and the examination of the impact of geological conditions on the biotransformation process was facilitated by the unique combination of the applied methods. There is thus significant benefit from deploying an extended array of methods for these investigations, with the potential to reduce costs involved in remediation of contaminated sediment and groundwater.
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| 20. |
- Strand, Malin, et al.
(författare)
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The Bacterial (Vibrio alginolyticus) Production of Tetrodotoxin in the Ribbon Worm Lineus longissimus-Just a False Positive?
- 2016
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Ingår i: Marine Drugs. - Basel : MDPI AG. - 1660-3397. ; 14:4
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Tidskriftsartikel (refereegranskat)abstract
- We test previous claims that the bacteria Vibrio alginolyticus produces tetrodotoxin (TTX) when living in symbiosis with the nemertean Lineus longissimus by a setup with bacteria cultivation for TTX production. Toxicity experiments on the shore crab, Carcinus maenas, demonstrated the presence of a paralytic toxin, but evidence from LC-MS and electrophysiological measurements of voltage-gated sodium channel-dependent nerve conductance in maleWistar rat tissue showed conclusively that this effect did not originate from TTX. However, a compound of similar molecular weight was found, albeit apparently non-toxic, and with different LC retention time and MS/MS fragmentation pattern than those of TTX. We conclude that C. maenas paralysis and death likely emanate from a compound <5 kDa, and via a different mechanism of action than that of TTX. The similarity in mass between TTX and the Vibrio-produced low-molecular-weight, non-toxic compound invokes that thorough analysis is required when assessing TTX production. Based on our findings, we suggest that re-examination of some published claims of TTX production may be warranted.
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| 21. |
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| 22. |
- Munthe, Christian, 1962
(författare)
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Precaution, bioethics and normative justification
- 2015
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Ingår i: Monash Bioethics Review. - : Springer Science and Business Media LLC. - 1321-2753 .- 1836-6716. ; 33:2, s. 219-225
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Recension (övrigt vetenskapligt/konstnärligt)abstract
- Daniel Steel’s new book on the precautionary principle illustrates the need to work ahead to fuse perspectives of epistemology and philosophy of science with those of ethics to accomplish progress in the debate on the proper role of precaution in a broad selection of bioethical areas. Steel advances the territory greatly with regard to conceptual clarity and epistemology, but from a bioethics standpoint he is mistaken in discounting the need for ethical underpinnings of a sound theory of the precautionary principle.
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| 23. |
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| 24. |
- Kharazmi, Parastou, 1977-
(författare)
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Evaluation of Innovative Rehabilitation Technologies Utilising Polymer Composites for Aging Sewer Systems
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Water and wastewater sewer system maintenance is among the costliest aspects of infrastructure investment. The replacement of deteriorated lines is a difficult and expensive process that causes community disturbance and is generally not conducted fast enough to meet demand. To keep up with the rate of deterioration, the use of alternative rehabilitation technologies using polymer linings has increased significantly in recent years, both within Sweden and worldwide. Compared to the traditional pipe replacement method, these technologies are cost-effective, create less community disturbance, and offer a quick return to the service for the line. The main function of polymeric lining is to stabilise the condition of the pipeline, eliminate deterioration, and thereby extend the pipeline’s service life. Although rehabilitation technologies employing polymeric systems have been in use for over 30 years, there have been few technical assessments of either these technologies or the materials involved. Data gathered through the evaluation of these innovative technologies can make their benefits and limitations more widely understood, and can also be used to increase the effectiveness of the rehabilitation process in future.The main objective of this work was to contribute to an improved understanding of the most commonly used materials and methods employed in rehabilitation of wastewater and other applicable sewer lines in residential buildings in Sweden. The primary objective was not to prove that the emerging rehabilitation technologies work, but rather to increase knowledge of their weaknesses and strengths, identify any issues, and provide a technical assessment to support realistic expectations of pipeline rehabilitation. Gathering technical information in this way will help with the planning of future investigations; moreover, collecting extensive data will help to increase the effectiveness of the renewal works, aid progress in the field, and improve predictions regarding longevity and service life. As pipeline rehabilitation is still considered novel, and owing to the general lack of available data on the subject, a multi-approach study was carried out: this included evaluation of the polymeric materials’ performance in the presence of deteriorative factors, assessing the in-service state of the materials and lined sewers previously installed, monitoring the level of quality control implemented during previous rehabilitation works, and evaluating the environmental impacts of using pipe-lining technologies compared to pipe replacement. The techniques discussed included rehabilitation with epoxy and polyester resin-based lining materials, applied with brush-on and spray-on techniques, and cured-in-place pipe lining (installed by sending a resin-impregnated flexible tube inside the host pipe). Degradation of the resin-based lining materials was investigated via artificial aging involving immersion in water at elevated temperatures. The changes in materials that occurred during accelerated laboratory aging were tracked by means of various tests, including thermal and mechanical analyses, water absorption measurements and microscopy. The analysis focused on reinforced polyester-based and toughened epoxy-based lining materials in order to gain a better understanding of their performance as pipe lining. Moreover, the previously installed lined pipes and lining materials were also studied during laboratory examinations to evaluate the in-service performance of the materials and techniques under operating conditions over time, as well as to identify common defects. The state of the materials and the lined pipe were studied by means of different investigative methods, including visual inspection, microscopy, Fourier transform infrared spectroscopy, thickness measurement, thermal and mechanical analyses. This PhD work also includes an investigation to determine the level of quality control carried during some previous rehabilitation works. Data on the quality evaluation of previous rehabilitation works were gathered during visits to the work sites, as well as by analysing lined pipes that had already been installed. Finally, a comparative life-cycle assessment was undertaken to compare the environmental impacts of pipe replacement with those of alternative innovative rehabilitations, such as CIPP and coatings with polyester and epoxy polymeric systems. Data obtained from an LCA tool were used to facilitate comparison from an environmental perspective.Results from artificial aging in the lab indicated that the properties of polymeric lining materials changed significantly when high temperatures were combined with water exposure. However, the aging testing conducted for this study also found that the materials performed relatively well at temperatures close to the average temperatures inside sewerage systems. The results revealed that the polyester-based lining material was less sensitive when compared with epoxy-based lining materials during stimulated aging. Moreover, results from the in-service field demonstration (involving examination of 12 samples with up to 10 years of service, including reinforced polyester and modified epoxy linings or cured-in-place pipe (CIPP) lining) showed minimal evidence that the materials underwent significant deterioration after installation; instead, a majority of the common defects were found to be related to poor-quality installation practices. Because very few field samples were available to study, conclusions regarding overall performance could not be drawn. However, there is no evidence that these materials will not perform as expected during their service life when properly installed.Evaluating quality control of previous rehabilitation work revealed a gap between theory and practice where the level of quality control and documentation was concerned; furthermore, it also emerged that quality control and documentation is crucial to both the prevention of common issues and the overall effectiveness of the rehabilitation. Accordingly, a series of recommendations regarding the development of comprehensive quality control and quality assurance procedures (QC/QA) are provided in this work. These recommendations highlight the aspects that are most important to consider at each of several key stages (before installation, during installation, and after rehabilitation work is completed).Results from comparative life-cycle assessment (LCA) showed that alternative technologies, including cured-in-place (flexible sleeve) and coating techniques, have some advantages over pipe replacement from an environmental perspective. However, the choice to use one rehabilitation technology over another is a multi-stage decision-making process that should not be based solely on a single factor.This PhD work promotes an improved understanding of the limitations and benefits of polymeric lining through the testing performed and analyses conducted. This work highlights the need for improved quality control, and further suggests that developing a detailed and comprehensive quality control plan for each technology would provide higher and more consistent quality overall. The study also demonstrates that the long-term strength of any rehabilitation work depends on various factors, and that selecting one method over another must be a process based on extensive knowledge and understanding of each rehabilitation technology. No evidence was found to indicate that the materials could not perform well under working conditions if selected and installed appropriately. However, a larger number of field samples with longer in-service time and a more detailed technical history, along with a more extended experimental plan for laboratory investigations based on the results of this PhD work, will allow for the gathering of the data required to answer questions regarding life expectancy with a higher degree of certainty.
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| 25. |
- Wu, Xue, 1986, et al.
(författare)
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Ammonium recovery from reject water combined with hydrogen production in a bioelectrochemical reactor
- 2013
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Ingår i: Bioresource Technology. - : Elsevier BV. - 0960-8524 .- 1873-2976. ; 146, s. 530-536
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Tidskriftsartikel (refereegranskat)abstract
- In this study, a bioelectrochemical reactor was investigated for simultaneous hydrogen production and ammonium recovery from reject water, which is an ammonium-rich side-stream produced from sludge treatment processes at wastewater treatment plants. In the anode chamber of the reactor, microorganisms converted organic material into electrical current. The electrical current was used to generate hydrogen gas at the cathode with 96±6% efficiency. Real or synthetic reject water was fed to the cathode chamber where proton reduction into hydrogen gas resulted in a pH increase which led to ammonium being converted into volatile ammonia. The ammonia could be stripped from the solution and recovered in acid. Overall, ammonium recovery efficiencies reached 94% with synthetic reject water and 79% with real reject water. This process could potentially be used to make wastewater treatment plants more resource-efficient and further research is warranted.
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