| 1. |
- Giuffrida, L., et al.
(författare)
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Manipulation of laser-accelerated proton beam profiles by nanostructured and microstructured targets
- 2017
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Ingår i: Physical Review Accelerators and Beams. - 2469-9888. ; 20:8, s. 081301-
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Tidskriftsartikel (refereegranskat)abstract
- Nanostructured and microstructured thin foils have been fabricated and used experimentally as targets to manipulate the spatial profile of proton bunches accelerated through the interaction with high intensity laser pulses (6 x 1019 W/cm(2)). Monolayers of polystyrene nanospheres were placed on the rear surfaces of thin plastic targets to improve the spatial homogeneity of the accelerated proton beams. Moreover, thin targets with grating structures of various configurations on their rear sides were used tomodify the proton beam divergence. Experimental results are presented, discussed, and supported by 3D particle-in-cell numerical simulations.
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| 2. |
- Giuffrida, L., et al.
(författare)
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Nano and micro structured targets to modulate the spatial profile of laser driven proton beams
- 2017
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Ingår i: Journal of Instrumentation. - 1748-0221. ; 12:3, s. article no C03040 -
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Tidskriftsartikel (refereegranskat)abstract
- Nano and micro structured thin (μ m-scale) foils were designed, fabricated and irradiated with the high intensity laser system operating at LLC (Lund Laser Centre, Sweden) in order to systematically study and improve the main proton beam parameters. Nano-spheres deposited on the front (laser irradiated) surface of a flat Mylar foil enabled a small enhancement of the maximum energy and number of the accelerated protons. Nano-spheres on the rear side allowed to modify the proton beam spatial profile. In particular, with nanospheres deposited on the rear of the target, the proton beam spatial homogeneity was clearly enhanced. Silicon nitride thin foils having micro grating structures (with different step dimensions) on the rear surface were also used as targets to influence the divergence of the proton beam and drastically change its shape through a sort of stretching effect. The target fabrication process used for the different target types is described, and representative experimental results are shown and discussed along with supporting 3D particle-in-cell simulations. © 2017 IOP Publishing Ltd and Sissa Medialab srl.
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| 3. |
- Brannmark, C., et al.
(författare)
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Increased Adipogenesis of Human Adipose-Derived Stem Cells on Polycaprolactone Fiber Matrices
- 2014
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203 .- 1932-6203. ; 9:11
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Tidskriftsartikel (refereegranskat)abstract
- With accelerating rates of obesity and type 2 diabetes world-wide, interest in studying the adipocyte and adipose tissue is increasing. Human adipose derived stem cells differentiated to adipocytes in vitro - are frequently used as a model system for white adipocytes, as most of their pathways and functions resemble mature adipocytes in vivo. However, these cells are not completely like in vivo mature adipocytes. Hosting the cells in amore physiologically relevant environment compared to conventional two-dimensional cell culturing on plastic surfaces, can produce spatial cues that drive the cells towards a more mature state. We investigated the adipogenesis of adipose derived stem cells on electro spun polycaprolactone matrices and compared functionality to conventional two-dimensional cultures as well as to human primary mature adipocytes. To assess the degree of adipogenesis we measured cellular glucose-uptake and lipolysis and used a range of different methods to evaluate lipid accumulation. We compared the averaged results from a whole population with the single cell characteristics - studied by coherent anti-Stokes Raman scattering microscopy - to gain a comprehensive picture of the cell phenotypes. In adipose derived stem cells differentiated on a polycaprolactone-fiber matrix; an increased sensitivity in insulin-stimulated glucose uptake was detected when cells were grown on either aligned or random matrices. Furthermore, comparing differentiation of adipose derived stem cells on aligned polycaprolactone-fiber matrixes, to those differentiated in two-dimensional cultures showed, an increase in the cellular lipid accumulation, and hormone sensitive lipase content. In conclusion, we propose an adipocyte cell model created by differentiation of adipose derived stem cells on aligned polycaprolactone-fiber matrices which demonstrates increased maturity, compared to 2D cultured cells.
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| 4. |
- Hughes, William, et al.
(författare)
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Cheap and secure metatransactions on the blockchain using hash-based authorisation and preferred batchers
- 2023
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Ingår i: Blockchain-Research and Applications. - : Elsevier BV. - 2096-7209. ; 4:2
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Tidskriftsartikel (refereegranskat)abstract
- Smart contracts are self-executing programs running in the blockchain allowing for decentralised storage and execution without a middleman. On-chain execution is expensive, with miners charging fees for distributed execution according to a cost model defined in the protocol. In particular, transactions have a high fixed cost. We present MultiCall, a transaction-batching interpreter for Ethereum that reduces the cost of smart contract executions by gathering multiple users' transactions into a batch. Our current implementation of MultiCall includes the following features: the ability to emulate Ethereum calls and create transactions, both from MultiCall itself and using an identity unique to the user; the ability to cheaply pay Ether to other MultiCall users; and the ability to authorise emulated transactions on behalf of multiple users in a single transaction using hash-based authorisation rather than more expensive signatures. This improves upon a previous version of MultiCall. Our experiments show that MultiCall provides a saving between 57% and 99% of the fixed transaction cost compared with the standard approach of sending Ethereum transactions directly. Besides, we also show how to prevent an economic attack exploiting the metatransaction feature, describe a generic protocol for hash-based authorisation of metatransactions, and analyse how to minimise its off-chain computational and storage cost.
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| 5. |
- Kukkonen, J., et al.
(författare)
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Towards a Comprehensive Evaluation of the Environmental and Health Impacts of Shipping Emissions
- 2022
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Ingår i: Springer Proceedings in Complexity. - Cham : Springer International Publishing. - 2213-8684 .- 2213-8692. ; , s. 329-336
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Konferensbidrag (refereegranskat)abstract
- We present a new concept for marine research, applied in the EU-funded project EMERGE, “Evaluation, control and Mitigation of the EnviRonmental impacts of shippinG Emissions” (2020–2024; https://emerge-h2020.eu/ ). For the first time, both the various marine and atmospheric impacts of the shipping sector have been and will be comprehensively analyzed, using a concerted modelling and measurements framework. The experimental part of the project focuses on five European geographical case studies in different ecologically vulnerable regions, and a mobile onboard case study. The EMERGE consortium has also developed a harmonised and integrated modelling framework to assess the combined impacts of shipping emissions, both (i) on the marine ecosystems and (ii) the atmospheric environment. The first results include substantial refinements of a range of models to be applied, especially those for the STEAM and OpenDrift models. In particular, the STEAM (Ship Traffic Emission Assessment Model) model has been extended to allow for the effects of atmospheric and oceanographic factors on the fuel consumption and emissions of the ships. The OpenDrift model has been improved to take into account the partitioning, degradation, and volatilization of pollutants in water. The predicted emission and discharge values have been used as input for both regional scale atmospheric dispersion models, such as WRF-CMAQ (Weather Research and Forecasting—Community Multiscale Air Quality Model) and SILAM (System for Integrated modeLling of Atmospheric composition), and water quality and circulation models, such as OpenDrift (Open source model for the drifting of substances in the ocean) and Delft3D (oceanographic model). The case study regions are Eastern Mediterranean, Northern Adriatic Sea, the Lagoon of Aveiro, the Solent Strait and the Öresund Strait. We have also conducted a substantial part of the experimental campaigns scheduled in the project. The final assessment will include the benefits and costs of control and mitigation options affecting water quality, air pollution exposure, health impacts, climate forcing, and ecotoxicological effects and bioaccumulation of pollutants in marine biota.
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| 6. |
- Maasfeh, Lujain, et al.
(författare)
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Impaired Luminal Control of Intestinal Macrophage Maturation in Patients With Ulcerative Colitis During Remission
- 2021
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Ingår i: Cellular and Molecular Gastroenterology and Hepatology. - : Elsevier BV. - 2352-345X. ; 12:4, s. 1415-1432
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND & AIMS: Intestinal macrophages adopt a hyporesponsive phenotype through education by local signals. Lack of proper macrophage maturation in patients with ulcerative colitis (UC) in remission may initiate gut inflammation. The aim, therefore, was to determine the effects of fecal luminal factors derived from healthy donors and UC patients in remission on macrophage phenotype and function. METHODS: Fecal supernatants (FS) were extracted from fecal samples of healthy subjects and UC patients in remission. Monocytes were matured into macrophages in the presence of granulocyte-macrophage colony-stimulating factor without/with FS, stimulated with lipopolysaccharide, and macrophage phenotype and function were assessed. Fecal metabolomic profiles were analyzed by gas-chromatography/mass-spectrometry. RESULTS: Fecal luminal factors derived from healthy donors were effective in down-regulating Toll-like receptor signaling, cytokine signaling, and antigen presentation in macrophages. Fecal luminal factors derived from UC patients in remission were less potent in inducing lipopolysaccharide hyporesponsiveness and modulating expression of genes involved in macrophage cytokine and Toll-like receptor signaling pathways. Although phagocytic and bactericidal abilities of macrophages were not affected by FS treatment, healthy FS-treated macrophages showed a greater ability to suppress cluster of differentiation 4(+) T-cell activation and interferon gamma secretion compared with UC remission FS-treated counterparts. Furthermore, metabolomic analysis showed differential fecal metabolite composition for healthy donors and UC patients in remission. CONCLUSIONS: Our data indicate that UC patients in remission lack luminal signals able to condition macrophages toward a hyporesponsive and tolerogenic phenotype, which may contribute to their persistent vulnerability to relapse.
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| 7. |
- Magnusson, Daniel, 1978, et al.
(författare)
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Demonstration of a SANEX process in centrifugal contactors using the CyMe4-BTBP molecule on a genuine fuel solution
- 2009
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Ingår i: Solvent Extraction and Ion Exchange. - : Informa UK Limited. - 0736-6299 .- 1532-2262. ; 27:2, s. 97-106
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Tidskriftsartikel (refereegranskat)abstract
- Efficient recovery of minor actinides from a genuine spent fuel solution has been successfully demonstrated by the CyMe4-BTBP/DMDOHEMA extractant mixture dissolved in octanol. The continuous countercurrent process, in which actinides(III) were separated from lanthanides(III), was carried out in laboratory centrifugal contactors using an optimized flow-sheet involving a total of 16 stages. The process was divided into 9 stages for extraction from a 2 M nitric acid feed solution, 3 stages for lanthanide scrubbing, and 4 stages for actinide back-extraction. Excellent feed decontamination factors for Am (7000) and Cm (1000) were obtained and the recoveries of these elements were higher than 99.9%. More than 99.9% of the lanthanides were directed to the raffinate except Gd for which 0.32% was recovered in the product.
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| 8. |
- Magnusson, Daniel, 1978, et al.
(författare)
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Demonstration of a TODGA based Extraction Process for the Partitioning of Minor Actinides from a PUREX Raffinate
- 2009
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Ingår i: Solvent Extraction and Ion Exchange. - : Informa UK Limited. - 0736-6299 .- 1532-2262. ; 27:1, s. 26-35
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Tidskriftsartikel (refereegranskat)abstract
- Efficient recovery of minor actinides (MA) from genuine PUREX raffinate has been successfully demonstrated by the TODGA + TBP extractant mixture dissolved in an industrial aliphatic solvent TPH. The process was carried out in centrifugal contactors using an optimized flow-sheet involving a total of 32 stages, divided into 4 stages for extraction, 12 stages for scrubbing and 16 stages for back-extraction. Very high feed decontamination factors were obtained (Am, Cm 40 000) and the recovery of these elements was higher than 99.99%. Of the non-lanthanide fission products only Y and a small part of Ru were co-separated into the product fraction together with the lanthanides and the MA.
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| 9. |
- Magnusson, Daniel, 1978, et al.
(författare)
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Towards an optimized flow-sheet for a SANEX demonstration process using centrifugal contactors
- 2009
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Ingår i: Radiochimica Acta. - : Walter de Gruyter GmbH. - 0033-8230. ; 97:3, s. 155-159
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Tidskriftsartikel (refereegranskat)abstract
- The design of an efficient process flow-sheet requires accurate extraction data for experimental set-up used. Often this data is provided as equilibrium data. Due to the small hold-up volume compared to the flow rate in centrifugal contactors the time for extraction is often too short to reach equilibrium D-ratios. In this work single stage kinetics experiments have been carried out to investigate the D-ratio dependence of the flow rate and to compare this with equilibrium batch experiments for a SANEX system based on CyMe4-BTBP. The first centrifuge experiment was run with spiked solutions while in the second a genuine actinide/lanthanide fraction from a TODGA process was used. Three different flow rates were tested with each set-up. the results show that even with low flow rates, only around 9% of the equilibrium D-ratio (Am) was reached for the extraction in the spiked test and around 16% in the hot test (the difference is due to the size of the centrifuges). In the hot test the lanthanide scrubbing was inefficient whereas in the stripping both the actinides and the lanthanides showed good results. Based on these results improvements of the suggested flow-sheet is discussed.
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| 10. |
- Magnusson, Joel, 1991, et al.
(författare)
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Laser-Particle Collider for Multi-GeV Photon Production
- 2019
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 122:25
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Tidskriftsartikel (refereegranskat)abstract
- As an alternative to Compton backscattering and bremsstrahlung, the process of colliding high-energy electron beams with strong laser fields can more efficiently provide both a cleaner and brighter source of photons in the multi-GeV range for fundamental studies in nuclear and quark-gluon physics. In order to favor the emission of high-energy quanta and minimize their decay into electron-positron pairs, the fields must not only be sufficiently strong, but also well localized. We here examine these aspects and develop the concept of a laser-particle collider tailored for high-energy photon generation. We show that the use of multiple colliding laser pulses with 0.4 PW of total power is capable of converting more than 18% of multi-GeV electrons passing through the high-field region into photons, each of which carries more than half of the electron initial energy. © 2019 authors. Published by the American Physical Society.
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