| 1. |
- Hansson, Lars-Anders, et al.
(författare)
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Experimental evidence for a mismatch between insect emergence and waterfowl hatching under increased spring temperatures
- 2014
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Ingår i: Ecosphere. - : Ecological Society of America. - 2150-8925 .- 2150-8925. ; 5:9, s. 120-
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Tidskriftsartikel (refereegranskat)abstract
- By combining a large-scale experimental assessment on timing of insect emergence with longtermmonitoring of waterfowl hatching date, we here show that insect emergence is mainly driven bytemperature, whereas there is only a weak effect of increasing spring temperatures on inter-annualvariability in observations of waterfowl chicks. Hence, a change in timing of the mass-emergence of insectsfrom lakes and wetlands, which is the crucial food source for waterfowl chicks, will likely result in aconsumer/resource mismatch in a future climate change perspective. Specifically, we experimentally showthat a moderate increase in temperature of 38C above ambient, expected to occur within 25–75 years, leadsto a considerably (2 weeks) earlier, and more pronounced, peak in insect emergence (Chironomus sp).Moreover, by utilizing long-term Citizen Science databases, ranging over several decades, we also showthat common waterfowl species are unable to significantly adjust their reproduction to fit futuretemperature increase. Hence, based on our data we predict a future mismatch between insect emergenceand waterfowl species basing their reproduction on temperature. This will have a profound impact onreproductive success and population dynamics of many aquatic birds, as well as on freshwaterbiodiversity.
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| 2. |
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| 3. |
- Mattsson, Karin, et al.
(författare)
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Translocation of 40 nm diameter nanowires through the intestinal epithelium of Daphnia magna
- 2016
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Ingår i: Nanotoxicology. - : Informa UK Limited. - 1743-5390 .- 1743-5404. ; 10:8, s. 1160-1167
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Tidskriftsartikel (refereegranskat)abstract
- Nanowires (NWs) have unique electrical and optical properties of value for many applications including lighting, sensing, and energy harnessing. Consumer products containing NWs increase the risk of NWs being released in the environment, especially into aquatic ecosystems through sewage systems. Daphnia magna is a common, cosmopolitan freshwater organism sensitive to toxicity tests and represents a likely entry point for nanoparticles into food webs of aquatic ecosystems. Here we have evaluated the effect of NW diameter on the gut penetrance of NWs in Daphnia magna. The animals were exposed to NWs of two diameters (40 and 80 nm) and similar length (3.6 and 3.8 μm, respectively) suspended in water. In order to locate the NWs in Daphnia, the NWs were designed to comprise one inherently fluorescent segment of gallium indium phosphide (GaInP) flanked by a gallium phosphide (GaP) segment. Daphnia mortality was assessed directly after 24 h of exposure and 7 days after exposure. Translocation of NWs across the intestinal epithelium was investigated using confocal fluorescence microscopy directly after 24 h of exposure and was observed in 89% of Daphnia exposed to 40 nm NWs and in 11% of Daphnia exposed to 80 nm NWs. A high degree of fragmentation was observed for NWs of both diameters after ingestion by the Daphnia, although 40 nm NWs were fragmented to a greater extent, which could possibly facilitate translocation across the intestinal epithelium. Our results show that the feeding behavior of animals may enhance the ability of NWs to penetrate biological barriers and that penetrance is governed by the NW diameter.
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| 4. |
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| 5. |
- Book, Frida, 1989, et al.
(författare)
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Ecotoxicity screening of seven different types of commercial silica nanoparticles using cellular and organismic assays : Importance of surface and size
- 2019
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Ingår i: NanoImpact. - : Elsevier BV. - 2452-0748. ; 13, s. 100-111
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Tidskriftsartikel (refereegranskat)abstract
- We show that seven different types of commercial, biocide-free, colloidal silica products with mean particle sizes between 17 and 88 nm with 3 different surface chemistries (Na-stabilized, aluminized and silane-modified) are not toxic to the bacterium Pseudomonas putida, and the algae Raphidocelis subcapitata in the concentration range 5–500 mg/L. They are also not acutely toxic to Daphnia magna at concentrations up to 10,000 mg/L. Six silica particles are toxic to the gill cell line RTgill-W1 from Rainbow trout (Oncorhynchus mykiss), showing a clear concentration-response relationship with EC50 values between 13 and 92 mg/L. Toxicity in the fish cells decreases with increasing hydrodynamic size and is dependent on particle surface area. The average EC50 across the tested particles is 2.1 (±0.3) m2/L. Surface modifications clearly impact toxicity, with silane-modified particles showing no cytotoxicity. The reduced number of free silanol groups on the surface of the silane modified particle, in combination with an increased steric hindrance that prevents contact with the cells is a possible mechanism for the observed lack of toxicity. This is also in line with previous studies on silica nanoparticles in human toxicology. Overall, these findings show a generally low ecotoxicity of silica nanoparticles and indicate that silica particles of different sizes but identical surface chemistry could potentially be grouped into an assessment group under regulation such as REACH.
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| 6. |
- Cedervall, Tommy, et al.
(författare)
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Workshop on Environmental Nanosafety: Biological Interactions of Plastic Nanoparticles
- 2019
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Ingår i: Journal of Chemical Education. - : American Chemical Society (ACS). - 0021-9584 .- 1938-1328. ; 96:9, s. 1967-1970
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Tidskriftsartikel (refereegranskat)abstract
- The one-hour workshop, containing both a demonstration and hands-on experiments on the topic of nanosafety, is based on current science on a topic of general interest. The workshop aims to provide a deeper knowledge and understanding of nanoparticles. The participants get an introduction to what nanoparticles are, why nanosized materials are interesting, how nanomaterials interact with biological molecules, and potential risks associated with nanoparticles. Furthermore, by participating in the workshop the audience gains insights into how research about nanoparticles is conducted. The participants carry out experiments to demonstrate that daily-used plastic products can be disintegrated into particles in the nanometer size range, which may have important implications for the environment.
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| 7. |
- Colledani, M., et al.
(författare)
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Analytical methods to support continuous improvements at Scania
- 2010
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Ingår i: International Journal of Production Research. - : Informa UK Limited. - 0020-7543 .- 1366-588X. ; 48:7, s. 1913-1945
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Tidskriftsartikel (refereegranskat)abstract
- Considerable effort is usually devoted by companies to ensure the competitiveness of their manufacturing systems. This makes continuous improvement a central topic in production management activities. Less attention is given to the methods that drive improvement and to the way actions are defined and selected. In the literature, analytical models and simulation are the most widely used tools for manufacturing systems' performance evaluation and improvement. In practice, simple approaches, mainly based on experience, seems to be the best compromise to face this problem. In a collaboration project between Politecnico di Milano ( Milano, Italy), Kungliga Tekniska hogskolan ( Stockholm, Sweden) and Scania CV AB (Sodertalje, Sweden) within the European Network of Excellence VRL-KCiP we proposed a new methodology, based on analytical methods, to support the company in manufacturing system productivity improvement through re-configuration. The application of this approach to the Scania six-cylinder engine-block machining line enabled a remarkable increment in throughput by selecting analytically the most suitable improvement actions.
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| 8. |
- Ekvall, Mikael T., et al.
(författare)
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Adsorption of bio-organic eco-corona molecules reduces the toxic response to metallic nanoparticles in Daphnia magna
- 2021
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Ingår i: Scientific Reports. - : Springer Nature. - 2045-2322. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- As the use of engineered nanomaterials increases, so does the risk of them spreading to natural ecosystems. Hitherto, knowledge regarding the toxic properties of nanoparticles (NP's) and their potential interactions with natural bio-organic molecules adsorbed to them, and thereby forming surface coronas, is limited. However, we show here that the toxic effect of NPs of tungsten carbide cobalt (WC-Co) and cobalt (Co) on the crustacean Daphnia magna is postponed in the presence of natural biological degradation products (eco-corona biomolecules). For Daphnia exposed to WC-Co NPs the survival time increased with 20-25% and for Co NPs with 30-47% after mixing the particles with a solution of eco-corona biomolecules before exposure. This suggests that an eco-corona, composed of biomolecules always present in natural ecosystems, reduces the toxic potency of both studied NPs. Further, the eco-coronas did not affect the particle uptake, suggesting that the reduction in toxicity was related to the particle-organism interaction after eco-corona formation. In a broader context, this implies that although the increasing use and production of NPs may constitute a novel, global environmental threat, the acute toxicity and long-term effects of some NPs will, at least under certain conditions, be reduced as they enter natural ecosystems.
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| 9. |
- Ekvall, Mikael T., et al.
(författare)
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Behavioural responses to co-occurring threats of predation and ultraviolet radiation in Daphnia
- 2020
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Ingår i: Freshwater Biology. - : Wiley. - 0046-5070 .- 1365-2427. ; 65:9, s. 1509-1517
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Tidskriftsartikel (refereegranskat)abstract
- Organisms in the wild are faced with multiple threats and a common response is a change in behaviour. To disentangle responses to several threats, we exposed two differently sized species of the freshwater invertebrate Daphnia to solar ultraviolet radiation (UVR) and predation from either moving pelagic or benthic ambush predators. Using an advanced nanotechnology-based method, we tracked the three-dimensional movements of those mm-sized animals at the individual level. Each behavioural trial was performed both under conditions resembling night (no UVR) and day (UVR) and we examined patterns of the depth distribution and swimming speed by Daphnia across three treatments: no predator (control); bottom-dwelling damselfly (Calopteryx sp.); and fish (stickleback, Pungitius pungitius) predators. We also quantified the actual predation rate by the two predators on the two Daphnia species, Daphnia manga and Daphnia pulex. We show that individual Daphnia are able to identify predators with different feeding habitats, rank multiple and simultaneously occurring risks and respond in accordance with the actual threat; complex responses that are generally associated with larger animals. In a broader context, our results highlight and quantify how a cocktail of everyday threats is perceived and handled by invertebrates, which advances our understanding of species distribution in space and time, and thereby of population dynamics and ecosystem function in natural ecosystems.
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| 10. |
- Ekvall, Mikael T., et al.
(författare)
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Environmental impact of nanoplastics from fragmentized consumer plastics : Final project report
- 2022
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Misplaced plastics is an ongoing environmental problem. The breakdown of plastics into smaller pieces, microplastics, likely cause additional environmental burdens as they affect animals and plants at the beginning of the food chain. This may be even more true for the smallest of microplastics: the nano plastics as they will behave differently in nature and interact in new ways with organisms and potentially be taken up by the organisms and affect internal organs. The small size of nano plastics and their chemical resemblance with the surrounding environment makes them difficult to find, isolate and study. Most of what is known about nano plastics behavior in nature and their effect on nature derives from studies using commercially available polystyrene nanoparticles. These are probably different in many ways, such as structure, surface chemistry, and size distribution, compared to nano plastics broken down in nature from plastic debris. Despite this, we have used polystyrene nanoparticles to study knowledge gaps. The toxicity to zooplankton Daphnia magna (D. magna) of small positively charged amine-modified polystyrene nanoparticles is not affected by protein-induced aggregation. All tested polystyrene nanoparticles were toxic to D. magna regardless of their toxicity in acute tests. Proteins bound to polystyrene nanoparticles after filtration by D. magna were different on acutely and non-acutely toxic particles which may imply different mechanisms behind the toxicity. In order to study the effect of nano plastics that resemble what can be expected in nature we have mechanically broken down 8 different plastics and rubbers from 14 different consumer products and isolated the nano plastics. Careful characterization shows that the nano plastics are irregular in shape, have a slightly negative surface charge, and often have a strongly oxidized surface compared to the starting material. The nano sized fractions are not toxic to D. magna in the used concentrations. In contrary, for at least two plastics High Density Polyethylene (HDPE) and Polylactic acid (PLA) thoracoplasties increase the lifetime of the D. magna probably because the nano plastics can be utilized by bacteria which in turn serve as additional food for the zooplankton. However, leached additives and/or smaller polymers from HDPE are toxic to D. magna. We have also seen that UV irradiation further degrade polystyrene nanoparticles. The bacterial growth and the UV breakdown may imply that the nano plastics breakdown faster than believed in nature and that they with time may disappear.
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