| 1. |
- Abbasi Aval, Negar, 1986-
(författare)
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Utilizing Biopolymers in 3D Tumor Modeling and Tumor Diagnosis
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Cancer represents a significant global public health challenge and ranks as the second mostcommon cause of death in the United States. The onset of cancer entails an initial phasewhere cells lose their polarity and disconnect from the normal basement membrane, allowingthem to form distinct three-dimensional (3D) configurations that interact with adjacent cellsand the surrounding microenvironment. Cells grown in 2D monolayers demonstrate differentgene expression patterns and different activation of signaling pathways compared to cellscultivated within the natural structure of tumor tissue of the same cell type. Multicellulartumor spheroids (MCTS) are extensively investigated as a well-studied model of organotypiccancer. These spheroids are formed by tumor cells, either alone or in combination with othercell types, and they can be created with or without the application of supportive scaffolds.The MCTSs are also considered promising models for preclinical assessments of chemosensitivity.However, the creation of these tumor spheroids presents challenges, as not alltumor cell lines can consistently form regular spheroids.Cellulose nanofibrils (CNF) have become essential as a sustainable and environmentallyfriendly material. For example, thin films, with inherent mechanical properties, and flexibility,offer versatility across various applications. Also known for its biocompatibility and non-toxicnature, native CNF is a natural option to use. Its fibrous structure closely mimics the collagenmatrix in human tissue, showing potential as an effective scaffold for 3D cell culture. In thisregard, an innovative Layer-by-Layer (LbL) coating technique using CNF-polyelectrolytebilayers was investigated to generate spheroids. This method constructs bilayers of CNFand polyelectrolytes and can coat various surfaces. In this thesis, the first focus was ondemonstrating the spheroid formation capability using low molecular weight polyelectrolytesin LbL assembly. Secondly, an investigation was conducted involving embedding of LbLgrownspheroids in a decellularized extracellular matrix (ECM) aiming to determine howECM, possessing suitable mechanical characteristics, could influence the cancer stem celltraits in spheroids. Thirdly, the thesis demonstrated the utilization of LbL for capturing andreleasing of circulating tumor cells. Lastly, the shift from using low molecular weightpolyelectrolytes in the LbL assembly to high molecular weight counterparts and analyzingthe differences in spheroid formation abilities to assess the underlying differences inmolecular weights of the polyelectrolytes was explored. All-in-all, employing the CNF-basedLbL surface coating strategy explored in the thesis has proven to be promising for thedevelopment of spheroid models closely resembling in vivo conditions and holds significantpotential for applications in drug development.
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| 2. |
- Braun, Robert, 1984-, et al.
(författare)
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Hopsan: An Open-Source Tool for Rapid Modelling and Simulation of Fluid and Mechatronic Systems
- 2020
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Ingår i: <em>Proceedings of the BATH/ASME 2020 Symposium on Fluid Power and Motion Control</em>. - 9780791883754
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Konferensbidrag (refereegranskat)abstract
- Hopsan is an open-source simulation package developed as a collaboration project between industry and academia. The simulation methodology is based on transmission line modelling, which provides several benefits such as linear model scalability, numerical robustness and parallel simulation. All sub-models are pre-compiled, so that no compilation is required prior to starting a simulation. Default component libraries are available for hydraulic, mechanic, pneumatic, electric and signal domains. Custom components can be written in C++ or generated from Modelica and Mathematica. Support for simulation-based optimization is provided using population-based, evolutionary or direct-search algorithms. Recent research has largely focused on co-simulation with other simulation tools. This is achieved either by using the Functional Mock-up Interface standard, or by tool-to-tool communications. This paper provides a description of the program and its features, the current status of the project, and an overview of recent and ongoing use cases from industry and academia.
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| 3. |
- Felton, Adam, et al.
(författare)
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Replacing monocultures with mixed-species stands : Ecosystem service implications of two production forest alternatives in Sweden
- 2016
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Ingår i: Ambio. - : Springer Science and Business Media LLC. - 0044-7447 .- 1654-7209. ; 45, s. 124-139
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Tidskriftsartikel (refereegranskat)abstract
- Whereas there is evidence that mixed-species approaches to production forestry in general can provide positive outcomes relative to monocultures, it is less clear to what extent multiple benefits can be derived from specific mixed-species alternatives. To provide such insights requires evaluations of an encompassing suite of ecosystem services, biodiversity, and forest management considerations provided by specific mixtures and monocultures within a region. Here, we conduct such an assessment in Sweden by contrasting even-aged Norway spruce (Picea abies)-dominated stands, with mixed-species stands of spruce and birch (Betula pendula or B. pubescens), or spruce and Scots pine (Pinus sylvestris). By synthesizing the available evidence, we identify positive outcomes from mixtures including increased biodiversity, water quality, esthetic and recreational values, as well as reduced stand vulnerability to pest and pathogen damage. However, some uncertainties and risks were projected to increase, highlighting the importance of conducting comprehensive interdisciplinary evaluations when assessing the pros and cons of mixtures.
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| 4. |
- Hak, Claudia S., 1976, et al.
(författare)
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A new approach to in-situ determination of roadside particle emission factors of individual vehicles under conventional driving conditions
- 2009
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Ingår i: Atmospheric Environment. - : Elsevier BV. - 1352-2310. ; 43:15, s. 2481-2488
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Tidskriftsartikel (refereegranskat)abstract
- A method for continuous on-road measurements of particle number emissions for both diesel- and petrol-fuelled vehicles is presented. The setup allows the determination of particle number emission factors on an individual vehicle basis by the simultaneous measurement of CO2 and particle concentrations. As an alternative to previous measurements on the kerbside, the sample is taken directly in the street, with the advantage of sampling in-situ within the exhaust plumes of passing vehicles, allowing the separation of the individual high-concentration plumes. The method was tested in two experiments that were conducted in the Gothenburg area. In the first study, which was performed at an urban roadside, we were able to determine particle emission factors from individual vehicles in a common car fleet passing the measurement site. The obtained emission factors were of the same order of magnitude (between 1.4 × 1012 and 1.8 × 1014 particles km−1) as values published in the recent literature for light duty vehicles. An additional on-road experiment was conducted at a rural road with four light duty reference vehicles (three of them petrol-powered and one diesel-powered) at driving speeds of 50 and 70 km h−1, realised with different engine speeds. The results of the traffic emission studies show that the method is applicable provided that instruments with an adequate dynamic range are used and that the traffic is not too dense. In addition, the variability in particle emissions for a specified driving condition was estimated.
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| 7. |
- Kärnell, Samuel, 1993-
(författare)
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Fluid Power Pumps and the Electrification : With a Focus on Discrete Displacement Control in Load Handling Applications
- 2020
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- More and more vehicles are being electrified. Mobile working machines and heavy trucks are not excluded, and these machines are often hydraulically intense. Electrification entails new requirements for the hydraulic system and its components, and these requirements must be taken into consideration.Hydraulic systems have looked similar for a long time, but now there is an opportunity to advance. Many things change when a diesel engine is replaced with an electric motor. For example, variable-speed control becomes more relevant, electric regeneration becomes possible, and the use of multiple prime movers becomes an attractive alternative. The noise from the hydraulic system will also be more noticeable when the diesel engine is gone. Furthermore, the introduction of batteries to the system makes the energy more valuable, since batteries are heavy and costly compared to a diesel tank. Therefore, it is commercially viable to invest in the hydraulic system.This thesis revolves around the heart of the hydraulic system, that also is the root of all evil. That is the pump. Traditionally, a pump has had either a fixed displacement or a continuously variable displacement. Here, the focus is on something in between, namely a pump with discrete displacement. The idea of discrete displacement is far from unique, but has not been investigated in detail in combination with variable speed before. In this thesis, a novel design for a quiet pump with discrete displacement is presented and analysed. The results show that discrete displacement is relevant from an energy perspective for machines working extensively at high pressure levels and with low flow rates, and that a few discrete values are enough to make a significant difference. However, for other cycles, the possible energy gains are very limited, but the discrete displacement can be a valuable feature if downsizing the electric machine is of interest.
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| 8. |
- Mackay, Heather, 1976-, et al.
(författare)
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Getting invasive species on the political agenda : agenda setting and policy formulation in the case of ash dieback in the UK
- 2017
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Ingår i: Biological Invasions. - : Springer. - 1387-3547 .- 1573-1464. ; 19:7, s. 1953-1970
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Tidskriftsartikel (refereegranskat)abstract
- This study reviews how the issue of ash dieback has been placed on the political agenda in the UK, a country where the disease has affected one of the largest national extents, thus representing a particularly severe case. Comparisons are made between how the scientific community framed the ash dieback threat and the resulting response strategy and how both the media and the British government framed the problem. Representing one example of media framing, the study analyses one British newspaper’s coverage of the disease and the response strategies (the Daily Telegraph). The analysis highlights a gap between the biologically rooted perspective and the perspective of policymakers, where policy must manoeuvre between disparate viewpoints and needs. Crucially, none of Pautasso et al.’s (Biol Conserv 158:37–49, 2013) five plant-science-based solutions were explicitly adopted by the British Government in their response strategy to ash dieback disease. The same is true of the biological control recommendations offered by Kirisits et al. (J Agric Ext Rural Dev 4(9):230–235, 2012). Instead, the government adopted a broader, more comprehensive approach than that recommended by plant scientists. The present analysis thus provides an example of a holistic perspective on the multiple competing factors that policymakers must navigate in their attempts to delineate action. It highlights instances in which proposed biological responses were rendered less applicable by a failure to understand the agenda-setting process and the policy-making arena. The present findings suggest that an improved understanding of the factors influencing agenda setting and policy action is essential to arriving at a more effective and integrated understanding of responses to biological threats.
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| 10. |
- Pettersson, Maria, 1976, et al.
(författare)
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Det underskattade samtalet väljarna emellan
- 2004
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Ingår i: Oscarsson, H. & Holmberg, S. (red). Kampen om euron. - Göteborg : Statsvetenskapliga institutionen, Göteborgs universitet. - 9189246152
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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