| 1. |
- Ceberg, Sofie, et al.
(författare)
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Tumor-tracking radiotherapy of moving targets; verification using 3D polymer gel, 2D ion-chamber array and biplanar diode array
- 2010
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Ingår i: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 250:1, s. 235-239
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to carry out a dosimetric verification of a dynamic multileaf collimator (DMLC)-based tumor-tracking delivery during respiratory-like motion. The advantage of tumor-tracking radiation delivery is the ability to allow a tighter margin around the target by continuously following and adapting the dose delivery to its motion. However, there are geometric and dosimetric uncertainties associated with beam delivery system constraints and output variations, and several investigations have to be accomplished before a clinical integration of this tracking technique. Two types of delivery were investigated in this study I) a single beam perpendicular to a target with a one dimensional motion parallel to the MLC moving direction, and II) an intensity modulated arc delivery (RapidArc®) with a target motion diagonal to the MLC moving direction. The feasibility study (I) was made using an 2D ionisation chamber array and a true 3D polymer gel. The arc delivery (II) was verified using polymer gel and a biplanar diode array. Good agreement in absorbed dose was found between delivery to a static target and to a moving target with DMLC tracking using all three detector systems. However, due to the limited spatial resolution of the 2D array a detailed comparison was not possible. The RapidArc® plan delivery was successfully verified using the biplanar diode array and true 3D polymer gel, and both detector systems could verify that the DMLC-based tumor-tracking delivery system has a very good ability to account for respiratory target motion.
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| 2. |
- Chai, Guocai, 1956-, et al.
(författare)
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Roles of Nitrogen on TWIP in Advanced Austenitic Stainless Steels
- 2022
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Ingår i: Steel Research International. - : Wiley. - 1611-3683 .- 1869-344X.
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Tidskriftsartikel (refereegranskat)abstract
- The influence of nitrogen on the mechanical properties of two high Ni containing advanced austenitic stainless steels with low stacking fault energies is investigated. The results show that increase of nitrogen content greatly increases both strength and elongation of the steel at the same time. At the cryogenic temperature, the steels show a twin induced plasticity behavior. Ab initio calculations indicate that the increase of nitrogen slightly increases the stacking fault energy and consequently the critical shear stress for twin initiation in the steel. However, addition of nitrogen significantly increases the flow stress. This leads to a smaller critical strain for twin initiation and promotes deformation twinning in the high nitrogen steel. This is confirmed by the microstructure investigation. Deformation in steels is a competitive process between slip and twinning. Dislocation slip is dominant at low strain range, but formation of stacking fault and twinning become important in the later stages of deformation. At cryogenic temperature, it is mainly deformation twinning. The influence of nitrogen addition on magnetic property and its effect on deformation twinning are also discussed. The present study increases the understanding for the development of high-performance and low-cost advanced austenitic stainless steels.
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| 3. |
- Chalapathi, Darshan, et al.
(författare)
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Deformation twinning and the role of stacking fault energy during cryogenic testing of Ni-based superalloy 625
- 2024
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Ingår i: Materials Science & Engineering. - 0921-5093 .- 1873-4936. ; 898
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Tidskriftsartikel (refereegranskat)abstract
- Ni-based superalloys play a crucial role in various high-temperature applications, where their exceptional mechanical properties and resistance to corrosion are highly desirable. However, their response to low temperatures, especially concerning strain hardening, microstructural evolution, and deformation mechanisms, requires further scrutiny. In this study, we investigate the influence of temperature on the stacking fault energy (SFE) and its implications on deformation twinning in Alloy 625. Uniaxial tensile tests are performed at 298 K, 173 K and 77 K. The study reveals a notable increase in strain hardening at intermediate strain levels, suggesting the activation of a secondary deformation mechanism. To gain deeper insights, crystal plasticity-based simulations using the DAMASK framework are employed, complementing the experimental outcomes. Deformation twins are consistently observed at all temperatures, albeit with a small volume fraction and thickness. The critical strain for twinning decreased with decreasing temperature. Based on the numerous literature studies, experimental and computational observations, the SFE of the material is estimated to be constant over the studied temperature range.
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| 4. |
- Edvardsson, Anneli, et al.
(författare)
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Verification of motion induced thread effect during tomotherapy using gel dosimetry
- 2015
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Ingår i: 8th International Conference on 3D Radiation Dosimetry (IC3DDOSE). - : IOP Publishing. - 1742-6596 .- 1742-6588. ; 573, s. 012048-012048
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Konferensbidrag (refereegranskat)abstract
- The purpose of the study was to evaluate how breathing motion during tomotherapy (Accuray, CA, USA) treatment affects the absorbed dose distribution. The experiments were carried out using gel dosimetry and a motion device simulating respiratory-like motion (HexaMotion, ScandiDos, Uppsala, Sweden). Normoxic polyacrylamide gels (nPAG) were irradiated, both during respiratory-like motion and in a static mode. To be able to investigate interplay effects the static absorbed dose distribution was convolved with the motion function and differences between the dynamic and convolved static absorbed dose distributions were interpreted as interplay effects. The expected dose blurring was present and the interplay effects formed a spiral pattern in the lower dose volume. This was expected since the motion induced affects the preset pitch and the theoretically predicted thread effect may emerge. In this study, the motion induced thread effect was experimentally verified for the first time.
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| 5. |
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| 6. |
-
Exhibition: Space Waves and a Tale : Hannes Alfvén (1908–1995). Nobel Prize laureate in physics 1970.
- 2022
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Konstnärligt arbeteabstract
- The exhibition Space Waves and a Tale presented parts of Alfvén's extensive research, his community engagement and last but not least, his fictional story The tale of the great computing machine from 1966. In 1970 KTH professor Hannes Alfvén (1908 – 1995) was awarded the Nobel Prize in physics for his discoveries and applications in plasma physics. The exhibition Space Waves and a Tale presented parts of Alfvén's extensive research, his community engagement and his fictional story The tale of the great computing machine from 1966.Alfvén's research allow us to explore all corners of the universe – from the auroras on earth to the auroras on other planets, from solar wind to stellar wind, from plasma phenomena in the laboratory to astrophysical plasma phenomena in ours and other galaxies.The tale of the great computing machine is a satirical tale that tells the story of a future society controlled by computers and is also the source of inspiration for an opera with the same name.As part of the exhibition Space Waves and a Tale visitors were invited to share their visions of how future technology will shape our lives and societies. Two students from the KTH School of Architecture have contributed to the exhibition by designing and building a flexible and sustainable exhibition module. Students from BOOMERANG REXUS participated with objects related to aerospace research.Space Waves and a Tale was produced by the project group for KTH 200 years anniversary celebration together with KTH Library, The Opera: The Tale of the Great Computing Machine, the Division of Space and Plasma Physics and the KTH School of Architecture.In connection with the exhibithion there was a book discussion, popular science lecture and a class visit.
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| 7. |
- Fagerqvist, Therese, et al.
(författare)
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Monoclonal antibodies selective for α-synuclein oligomers/protofibrils recognize brain pathology in Lewy body disorders and α-synuclein transgenic mice with the disease-causing A30P mutation
- 2013
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Ingår i: Journal of Neurochemistry. - : Wiley-Blackwell. - 0022-3042 .- 1471-4159. ; 126:1, s. 131-144
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Tidskriftsartikel (refereegranskat)abstract
- Inclusions of intraneuronal alpha-synuclein (-synuclein) can be detected in brains of patients with Parkinson's disease and dementia with Lewy bodies. The aggregation of -synuclein is a central feature of the disease pathogenesis. Among the different -synuclein species, large oligomers/protofibrils have particular neurotoxic properties and should therefore be suitable as both therapeutic and diagnostic targets. Two monoclonal antibodies, mAb38F and mAb38E2, with high affinity and strong selectivity for large -synuclein oligomers were generated. These antibodies, which do not bind amyloid-beta or tau, recognize Lewy body pathology in brains from patients with Parkinson's disease and dementia with Lewy bodies and detect pathology earlier in -synuclein transgenic mice than linear epitope antibodies. An oligomer-selective sandwich ELISA, based on mAb38F, was set up to analyze brain extracts of the transgenic mice. The overall levels of -synuclein oligomers/protofibrils were found to increase with age in these mice, although the levels displayed a large interindividual variation. Upon subcellular fractionation, higher levels of -synuclein oligomers/protofibrils could be detected in the endoplasmic reticulum around the age when behavioral disturbances develop. In summary, our novel oligomer-selective -synuclein antibodies recognize relevant pathology and should be important tools to further explore the pathogenic mechanisms in Lewy body disorders. Moreover, they could be potential candidates both for immunotherapy and as reagents in an assay to assess a potential disease biomarker.
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| 8. |
- German Millberg, Lena, 1958-, et al.
(författare)
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Academic learning for specialist nurses: a Grounded Theory study
- 2014
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Ingår i: Nurse Education in Practice. - Oxford : Elsevier. - 1471-5953 .- 1873-5223. ; 14:6, s. 714-721
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The aim was to explore the major concerns of specialist nurses pertaining to academic learning during their education and initial professional career. Specialist nursing education changed in tandem with the European educational reform in 2007. At the same time, greater demands were made on the healthcare services to provide evidence-based and safe patient-care. These changes have influenced specialist nursing programmes and consequently the profession. Grounded Theory guided the study. Data were collected by means of a questionnaire with open-ended questions distributed at the end of specialist nursing programmes in 2009 and 2010. Five universities were included. Further, individual, pair and group interviews were used to collect data from 12 specialist nurses, 5-14 months after graduation. A major concern for specialist nurses was that academic learning should be "meaningful" for their professional future. The specialist nurses' "meaningful academic learning process" was characterised by an ambivalence of partly believing in and partly being hesitant about the significance of academic learning and partly receiving but also lacking support. Specialist nurses were influenced by factors in two areas: curriculum and healthcare context. They felt that the outcome of contribution to professional confidence was critical in making academic learning meaningful.
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| 9. |
- German Millberg, Lena, 1958-
(författare)
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Akademisering av specialistsjuksköterskans utbildning i Sverige : Spänningsförhållanden med anledning av utbildningsreform i enlighet med Bologna
- 2012
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Licentiatavhandlingens övergripande syfte var att studera konsekvenser av ökad akademisering och akademiskt lärande inom Svensk specialist-sjuksköterskeutbildning efter genomförande av ny utbildningsreform enligt Bologna.Bakgrund: Specialistsjuksköterskor förväntas i dagens hälso– och sjukvård att kunna bedriva en patientsäker och evidensbaserad vård, vilket kräver akademisk kompetens. Utbildningen till specialistsjuksköterska fördes i och med Bolognaprocessens införande i Sverige 2007 till avancerad utbildningsnivå. Både yrkesexamen och akademisk examen (magisterexamen) skulle inkluderas och integreras i samma utbildning. Detta medförde en förändring från en ämnesinriktad (samlingskodsinriktad) läroplan till en läroplan som syftar till att integrera ämnen (integrationskodsinriktad). Förutom ämnesintegrering skulle yrkesspecifika mål integreras med akademiska mål.Metod: Artikel I genomfördes i form av ett didaktiskt aktionsforskningsprojekt som pågick under 2½ år. En projektledningsgrupp (n=15-18) från fem lärosäten bildades. Denna grupp har aktivt deltagit i hela aktionsforskningsprocessen och vid projektmöten. Vid varje lärosäte utsågs en projektansvarig som ansvarade för den lokala aktionsforskningsprocessen. Dessa personer samlande in data i form av kursplaner, utbildningsplaner, studiehandledningar, minnesanteckningar från lärarmöten och möten med vårdverksamheter samt minnesanteckningar från forskargruppensmöten. Analys har gjorts med hjälp av konstant komparativ analysmetod. I artikel II användes konstruktivistisk Grounded Theory för att samla in och analysera data. Datainsamlingen påbörjades utifrån specialistsjuksköterskestudenters svar på en enkäts öppna fråga (n=120) i samband med utbildningens avslutning 2009 och 2010. Enkätsvaren reste frågor om specialistsjuksköterskans akademiska lärande. För att inhämta en djupare förståelse genomfördes intervjuer med specialistsjuksköterskor (n=12) som yrkesarbetat mellan 5 och 12 månader efter sin examen. Intervjuerna genomfördes från juni till oktober 2011. Avslutningsvis jämfördes svaren på den öppna enkätfrågan med analysen av intervjuerna.Resultat: Vid utbildningsreformens införande fanns pedagogiska motsättningar och didaktiska svårigheter som gav upphov till spänningsförhållanden mellan vårdutveckling, forskning, yrkesspecifika mål och akademiska mål. Spänningsförhållanden framkom också när specialistsjuksköterskorna inte erfor att deras akademiska kompetens tillvaratogs och värderades i vårdverksamheten. När stöd inte fanns för akademiskt lärande uppkom villrådighet och specialistsjuksköterskorna blev ambivalenta över om akademiskt lärande var meningsfullt. För att främja meningsfullt akademiskt lärande framhåller deltagarna betydelsen av samverkan och gemensamma arenor mellan lärosäten och vårdverksamhet där nyttoaspekten med akademiskt lärande tydliggörs. De spänningsförhållanden som framkommer var av både positiv och negativ karaktär.
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| 10. |
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| 11. |
- Gustafsson, Gabriel, et al.
(författare)
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Alpha-synuclein oligomer-selective antibodies reduce intracellular accumulation and mitochondrial impairment in alpha-synuclein exposed astrocytes
- 2017
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Ingår i: Journal of Neuroinflammation. - : Springer Science and Business Media LLC. - 1742-2094. ; 14
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Due to its neurotoxic properties, oligomeric alpha-synuclein (α-syn) has been suggested as an attractive target for passive immunization against Parkinson’s disease (PD). In mouse models of PD, antibody treatment has been shown to lower the levels of pathogenic α-syn species, including oligomers, although the mechanisms of action remain unknown. We have previously shown that astrocytes rapidly engulf α-syn oligomers that are intracellularly stored, rather than degraded, resulting in impaired mitochondria.Methods: The aim of the present study was to investigate if the accumulation of α-syn in astrocytes can be affected by α-syn oligomer-selective antibodies. Co-cultures of astrocytes, neurons, and oligodendrocytes were derived from embryonic mouse cortex and exposed to α-syn oligomers or oligomers pre-incubated with oligomer-selective antibodies.Results: In the presence of antibodies, the astrocytes displayed an increased clearance of the exogenously added α-syn, and consequently, the α-syn accumulation in the culture was markedly reduced. Moreover, the addition of antibodies rescued the astrocytes from the oligomer-induced mitochondrial impairment.Conclusions: Our results demonstrate that oligomer-selective antibodies can prevent α-syn accumulation and mitochondrial dysfunction in cultured astrocytes.
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| 12. |
- Hosseinnia, Ali, et al.
(författare)
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Ethane thermometry using rotational coherent anti-Stokes Raman scattering (CARS)
- 2017
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Ingår i: Proceedings of the Combustion Institute. - : Elsevier BV. - 1540-7489. ; 36:3, s. 4461-4468
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Tidskriftsartikel (refereegranskat)abstract
- The complete rotational CARS (coherent anti-Stokes Raman scattering) spectrum of ethane (C2H6) has for the first time been recorded instantaneously under high spectral resolution, and the potential for thermometry has been investigated. Experiments were performed in the temperature range 292-650K in pure ethane and in binary mixtures with nitrogen. A polarization technique was used to suppress the non-resonant contribution to the CARS signal. The ethane RCARS spectra show both S- and R-branch lines, which are more closely spaced than for the well-known nitrogen spectrum and located at much smaller Raman shifts. The peak signal strength was found to be around 240 times lower for ethane than for nitrogen (at 292K). Two main approaches for ethane thermometry are evaluated, which both show high potential. The first is a method in which a spectrum with unknown temperature is fitted using a library of experimental spectra recorded at various temperatures. The second is a method based on ratios of integrated signals in different spectral regions. A theoretical model for simulation of theoretical spectra is under development.
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| 13. |
- Hosseinnia, Ali, et al.
(författare)
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Rotational CARS thermometry and concentration measurements in ethane-nitrogen mixtures using Fourier analysis
- 2018
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Ingår i: Journal of Raman Spectroscopy. - : Wiley. - 0377-0486. ; 49:7, s. 1096-1108
-
Tidskriftsartikel (refereegranskat)abstract
- Rotational coherent anti-Stokes Raman scattering (CARS) is an established diagnostic technique for thermometry and species concentration measurements of di-atomics and tri-atomics in combustion processes; however, studies on hydrocarbon fuel molecules have been scarce. In this work, we have investigated the diagnostic potential for rotational CARS on ethane with emphasis on concentration measurements in mixtures with nitrogen. Rotational CARS spectra have periodic line structures, and because ethane and nitrogen spectra partially overlap, a novel Fourier analysis approach was developed and applied to facilitate evaluation of relative concentrations and temperatures. Instead of the standard procedure of spectral fitting using libraries of theoretically calculated spectra, the fitting was based on an experimental database of temperatures and relative ethane/nitrogen concentrations. The method was successfully demonstrated in an ethane diffusion flame where ethane, initially at room temperature, is heated downstream as well as mixed with increasing amounts of nitrogen. The evaluated temperatures and concentrations are in good agreement with computational fluid dynamic model simulations.
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| 14. |
- Kristensson, Elias, et al.
(författare)
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Stray light suppression in spectroscopy using periodic shadowing
- 2014
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Ingår i: Optics Express. - 1094-4087. ; 22:7, s. 7711-7721
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Tidskriftsartikel (refereegranskat)abstract
- It is well known that spectroscopic measurements suffer from an interference known as stray light, causing spectral distortion that reduces measurement accuracy. In severe situations, stray light may even obscure the existence of spectral lines. Here a novel general method is presented, named Periodic Shadowing, that enables effective stray light elimination in spectroscopy and experimental results are provided to demonstrate its capabilities and versatility. Besides its efficiency, implementing it in a spectroscopic arrangement comes at virtually no added experimental complexity. (C) 2014 Optical Society of America
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| 15. |
- Kristensson, Elias, et al.
(författare)
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Stray light suppression in spectroscopy using periodic shadowing
- 2014
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Ingår i: Optics Express. - : Optica Publishing Group. - 1094-4087. ; 22:7, s. 7711-7711
-
Tidskriftsartikel (refereegranskat)abstract
- It is well known that spectroscopic measurements suffer from an interference known as stray light, causing spectral distortion that reduces measurement accuracy. In severe situations, stray light may even obscure the existence of spectral lines. Here a novel general method is presented, named Periodic Shadowing, that enables effective stray light elimination in spectroscopy and experimental results are provided to demonstrate its capabilities and versatility. Besides its efficiency, implementing it in a spectroscopic arrangement comes at virtually no added experimental complexity.
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| 16. |
- Lindström, Veronica, et al.
(författare)
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Immunotherapy targeting α-synuclein protofibrils reduced pathology in (Thy-1)-h[A30P] α-synuclein mice
- 2014
-
Ingår i: Neurobiology of Disease. - : Elsevier BV. - 0969-9961 .- 1095-953X. ; 69, s. 134-143
-
Tidskriftsartikel (refereegranskat)abstract
- Several lines of evidence suggest that accumulation of aggregated alpha-synuclein (α-synuclein) in the central nervous system (CNS) is an early pathogenic event and therefore a suitable therapeutic target in Parkinson’s disease and other Lewy body disorders. In recent years, animal studies have indicated immunotherapy with antibodies directed against α-synuclein as a promising novel treatment strategy. Since large α-synuclein oligomers, or protofibrils, have been demonstrated to possess pronounced cytotoxic properties, such species should be particularly attractive as therapeutic targets. An α-synuclein protofibril-selective monoclonal antibody, mAb47, was evaluated in the (Thy-1)-h[A30P] α-synuclein transgenic mouse model, featuring an age- and motor dysfunction-associated increase of α-synuclein protofibrils in the CNS. As measured by ELISA, mAb47-treated mice displayed significantly lower levels of both soluble and membrane-associated protofibrils in the spinal cord. In addition, a trend for increased survival as a result of reduced motor symptoms was observed with antibody treatment. Taken together, this study demonstrates reduced levels of pathogenic α-synuclein and indicates a reduction of motor dysfunction in transgenic mice upon peripheral administration of an α-synuclein protofibril-selective antibody. Thus, immunotherapy with antibodies targeting toxic α-synuclein species holds promise as a future disease-modifying treatment in Parkinson’s disease and related disorders.
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| 17. |
- Nilsson, Victor, et al.
(författare)
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The need for liquidity and the capital structure of Swedish Banks following the financial crisis
- 2014
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Ingår i: International Journal of Finance & Banking Studies. - : SSBFNET. - 2147-4486. ; 3:2, s. 10-27
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Tidskriftsartikel (refereegranskat)abstract
- Banks had a large part in the developments taking place in the years after the outbreak of the crisis in 2007, as many banks had anexcessively low capital base, involving too much risk in its businesses. In this study, the largest four banks in Sweden have beeninvestigated. The financial crisis affected the banks differently, depending on the markets of expansion. Excessive risk-taking hasbeen found, where one bank expanded aggressively into new markets and did not appreciate the risks on these new markets. CEOcompensation and risk seeking boards are factors that might have caused such behaviour. All of the banks have made noticeablechanges to their capital structure, increasing it annually, accompanied by a risk-reduction movement in their assets to improve thestability in most of the banks. The new regulation’s focus on both quality and quantity is in accordance with the views that areexpressed in the framework. The banks have altered their goals to levels several per cent above the regulations, in contrast tobefore the crisis when they were often as close as possible. The impact of the new liquidity regulations has been limited, as thebanks continue to work with their internal measures. The banks have all changed their view of capital ratio and liquidity, wheremany of the banks have doubled the amount of these posts and now find these measures to be both beneficial and a way to gaintrust and stability.
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| 18. |
- Nordström, Carin, 1971-, et al.
(författare)
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Passion in hybrid entrepreneurship : the impact of entrepreneurial teams and tenure
- 2016
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Ingår i: Baltic Journal of Management. - 1746-5265 .- 1746-5273. ; 11:2, s. 167-186
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Tidskriftsartikel (refereegranskat)abstract
- Purpose – The present study draws on the theory of choice overload to examine how entrepreneurial tenure and involvement in entrepreneurial teams influence passion for engaging in entrepreneurship.Design/methodology/approach – A survey was administered to 262 Swedish hybrid entrepreneurs, which refers to individuals who engage in entrepreneurship while also maintaining wage work; this arrangement is becoming more and more common in the Nordic economies. Hypotheses proposed associations between the entrepreneurial tenure (the length of engagement in the side business) and entrepreneurial teams (leading the business with one or more team members) with passion for entrepreneurship. Logistic regression was used to test the hypotheses.Findings – Results from logistic regression support the hypotheses with three findings: 1) the longer the individual has had the side business, the less likely passion to be the main motive behind entrepreneurship; 2) passion is less likely to be the main motive behind entrepreneurship among those who are part of an entrepreneurial team, and 3) involvement in an entrepreneurial team strengthens the negative association between entrepreneurial tenure and passion for entrepreneurship.Research limitations/implications – The data are limited to the creative sector in Sweden and to the hybrid entrepreneurship context.Practical implications – The results support the impact of choice overload and the notions that entrepreneurship passion will decrease the longer the business is up running and if the venturing occurs with another team member. In practice,this means that interventions for re-kindling passion in entrepreneurship should focus on dealing with choice overload under conditions of long-term tenure and team-funded ventures. If entrepreneurswant tomaintain high levels of passion, quick and isolated entrepreneurial processes reduce the choice overload that may threaten maintaining a high passion for entrepreneurship.Originality/value – This study is the first to apply choice theory to an entrepreneurship context and to find support for possible negative effects of choice overload on passion for entrepreneurship.
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| 19. |
- Nordström, Eva, et al.
(författare)
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ABBV-0805, a novel antibody selective for soluble aggregated alpha-synuclein, prolongs lifespan and prevents buildup of alpha-synuclein pathology in mouse models of Parkinson's disease
- 2021
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Ingår i: Neurobiology of Disease. - : Elsevier. - 0969-9961 .- 1095-953X. ; 161
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Tidskriftsartikel (refereegranskat)abstract
- A growing body of evidence suggests that aggregated alpha-synuclein, the major constituent of Lewy bodies, plays a key role in the pathogenesis of Parkinson's disease and related alpha-synucleinopathies. Immunotherapies, both active and passive, against alpha-synuclein have been developed and are promising novel treatment strategies for such disorders. Here, we report on the humanization and pharmacological characteristics of ABBV-0805, a monoclonal antibody that exhibits a high selectivity for human aggregated alpha-synuclein and very low affinity for monomers. ABBV-0805 binds to a broad spectrum of soluble aggregated alpha-synuclein, including small and large aggregates of different conformations. Binding of ABBV-0805 to pathological alpha-synuclein was demonstrated in Lewy body-positive post mortem brains of Parkinson's disease patients. The functional potency of ABBV-0805 was demonstrated in several cellular assays, including Fc gamma-receptor mediated uptake of soluble aggregated alpha-synuclein in microglia and inhibition of neurotoxicity in primary neurons. In vivo, the murine version of ABBV-0805 (mAb47) displayed significant dose dependent decrease of alpha-synuclein aggregates in brain in several mouse models, both in prophylactic and therapeutic settings. In addition, mAb47 treatment of alpha-synuclein transgenic mice resulted in a significantly prolonged survival. ABBV-0805 selectively targets soluble toxic alpha-synuclein aggregates with a picomolar affinity and demonstrates excellent in vivo efficacy. Based on the strong preclinical findings described herein, ABBV-0805 has been progressed into clinical development as a potential disease-modifying treatment for Parkinson's disease.
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| 20. |
- Nordström, Emil, et al.
(författare)
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Raman linewidth measurements using time-resolved hybrid picosecond/nanosecond rotational CARS
- 2015
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Ingår i: Optics Letters. - 0146-9592. ; 40:24, s. 5718-5721
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Tidskriftsartikel (refereegranskat)abstract
- We report an innovative approach for time-domain measurements of S-branch Raman linewidths using hybrid picosecond/nanosecond pure-rotational coherent anti-Stokes Raman spectroscopy (RCARS). The Raman coherences are created by two picosecond excitation pulses and are probed using a narrow-band nanosecond pulse at 532 nm. The generated RCARS signal contains the entire coherence decay in a single pulse. By extracting the decay times of the individual transitions, the J-dependent Raman linewidths can be calculated. Self-broadened S-branch linewidths for nitrogen and oxygen at 293 K and ambient pressure are in good agreement with previous time-domain measurements. Experimental considerations of the approach are discussed along with its merits and limitations. The approach can be extended to a wide range of pressures and temperatures and has potential for simultaneous single-shot thermometry and linewidth determination. (C) 2015 Optical Society of America
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| 21. |
- Nordström, Joakim, 1971-
(författare)
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Deformation twinning in corrosion-resistant nickel alloys : with a rising nickel content
- 2024
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Sanicro 28 and Alloy 625 are corrosion-resistant nickel alloys with a fully austenitic structure and a very low carbon content, which means they are both well suited for cold working. Since the millennium shift deformation twinning has been a live research issue as it enhances strength and ductility simultaneously. As nickel has been pointed out as a high stacking fault energy element and deformation twinning should be promoted by a low stacking fault energy level they have been considered as opposite poles. Nonetheless, it is known since long that deformation twins can emerge in high stacking fault face centred cubic elements at low temperatures.In this thesis, we have investigated deformation twinning behaviour in corrosion-resistant nickel alloys. The objective is trying to distinguish between deformation twinning in TWIP steel and corrosion resistant nickel alloys regarding for instance size and bundles.Interrupted uniaxial tensile tests have been performed at several cold working temperatures for the alloys: Sanicro 28 (31% nickel) and Alloy 625 (61% nickel). The microstructure has been characterized in homogeneous deformation volume, by scanning electron microscopy electron backscattering diffraction and electron channelling contrast imaging, transmission electron microscopy and X-ray diffraction. In one investigation fracture behaviour has also been studied with secondary electrons. Ab initio calculations, crystal plasticity modelling and DAMASK simulations have been performed to support emphasizing active deformation mechanisms.It has been revealed that deformation twinning can occur in high Ni alloys. With increasing deformation twinning levels, the diffuse necking decreases. Ab initio calculations indicates that the initiation of deformation twins cannot be determined solely by the stacking fault energy. Distinct features were discovered at low strains that could be rejected from being neither deformation twins nor stacking faults. Level of texture increases with increasing strain and decreasing temperature and the texture modes are changed with decreasing temperature.
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| 22. |
- Nordström, Joakim, 1971-, et al.
(författare)
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Temperature study of deformation twinning behaviour in Nickel-base Superalloy 625
- 2024
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Ingår i: Materials Science & Engineering. - 0921-5093 .- 1873-4936.
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Tidskriftsartikel (refereegranskat)abstract
- Deformation behaviour in the Nickel-base superalloy 625 has been studied by tensile testing at four temperatures: 295, 223, 173 and 77 K. The microstructure has been investigated using TEM, FIB-SEM, EBSD and ECCI techniques. Deformation in the alloy turns out to be a competitive course of events between at least two deformation mechanisms, namely dislocation slip and deformation twinning. Slip is the predominant deformation mechanism at higher temperatures. While at 77 K, deformation induced twinning gives an extra degree of freedom as one of the main deformation mechanisms, i.e., the material shows a twin induced plasticity, TWIP, behaviour. Ab initio calculations indicate that the influence of cryogenic/sub-zero temperatures on the stacking fault energy of this alloy can be limited and that the formation of deformation twins cannot be determined solely by the stacking fault energy. The results implies that it is the critical strain and strain hardening rate that influences the deformation twinning onset and twinning rate.
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| 23. |
- Nordström, Joakim, 1971-, et al.
(författare)
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Temperature study of deformation twinning behaviour in nickel-base Superalloy 625
- 2024
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Ingår i: Materials Science & Engineering. - : Elsevier BV. - 0921-5093 .- 1873-4936. ; 907
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Tidskriftsartikel (refereegranskat)abstract
- Deformation behaviour in the Nickel-base superalloy 625 has been studied by tensile testing at four temperatures: 295, 223, 173 and 77 K. The microstructure has been investigated using TEM, FIB-SEM, EBSD and ECCI techniques. Deformation in the alloy turns out to be a competitive course of events between at least two deformation mechanisms, namely dislocation slip and deformation twinning. Slip is the predominant deformation mechanism at higher temperatures. While at 77 K, deformation induced twinning gives an extra degree of freedom as one of the main deformation mechanisms, i.e., the material shows a twin induced plasticity, TWIP, behaviour. Ab initio calculations indicate that the influence of cryogenic/sub-zero temperatures on the stacking fault energy of this alloy can be limited and therefore the formation of deformation twins cannot be determined solely by the stacking fault energy. The results implies that critical strain and strain hardening rate influences the deformation twinning onset and twinning rate.
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| 24. |
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| 25. |
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| 26. |
- Näsström, Thomas, et al.
(författare)
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Antibodies against alpha-synuclein reduce oligomerization in living cells
- 2011
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 6:10, s. e27230-
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Tidskriftsartikel (refereegranskat)abstract
- Recent research implicates soluble aggregated forms of α-synuclein as neurotoxic species with a central role in the pathogenesis of Parkinson’s disease and related disorders. The pathway by which α-synuclein aggregates is believed to follow a step-wise pattern, in which dimers and smaller oligomers are initially formed. Here, we used H4 neuroglioma cells expressing α-synuclein fused to hemi:GFP to study the effects of α-synuclein monoclonal antibodies on the early stages of aggregation, as quantified by Bimolecular Fluorescence Complementation assay. Widefield and confocal microscopy revealed that cells treated for 48 h with monoclonal antibodies internalized antibodies to various degrees. Oligomer-selective and C-terminal specific α-synuclein antibodies reduced the extent of α-synuclein dimerization/oligomerization, as indicated by decreased GFP fluorescence signal. Furthermore, ELISA measurements on lysates and conditioned media from antibody treated cells displayed lower α-synuclein levels compared to untreated cells, suggesting increased protein turnover. Taken together, our results propose that extracellular administration of monoclonal antibodies can modify or inhibit early steps in the aggregation process of α-synuclein, thus providing further support for passive immunization against diseases with α-synuclein pathology.
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| 27. |
- Persson, Emilia, et al.
(författare)
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MR-OPERA : A Multicenter/Multivendor Validation of Magnetic Resonance Imaging-Only Prostate Treatment Planning Using Synthetic Computed Tomography Images
- 2017
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Ingår i: International Journal of Radiation Oncology, Biology, Physics. - : ELSEVIER SCIENCE INC. - 0360-3016 .- 1879-355X. ; 99:3, s. 692-700
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To validate the dosimetric accuracy and clinical robustness of a commercially available software for magnetic resonance (MR) to synthetic computed tomography (sCT) conversion, in an MR imaginge-only workflow for 170 prostate cancer patients.Methods and Materials: The 4 participating centers had MriPlanner (Spectronic Medical), an atlas-based sCT generation software, installed as a cloud-based service. A T2-weighted MR sequence, covering the body contour, was added to the clinical protocol. The MR images were sent from the MR scanner workstation to theMriPlanner platform. The sCT was automatically returned to the treatment planning system. Four MR scanners and 2 magnetic field strengths were included in the study. For each patient, a CT-treatment plan was created and approved according to clinical practice. The sCT was rigidly registered to the CT, and the clinical treatment plan was recalculated on the sCT. The dose distributions from the CT plan and the sCT plan were compared according to a set of dose-volume histogram parameters and gamma evaluation. Treatment techniques included volumetric modulated arc therapy, intensity modulated radiation therapy, and conventional treatment using 2 treatment planning systems and different dose calculation algorithms.Results: The overall (multicenter/multivendor) mean dose differences between sCT and CT dose distributions were below 0.3% for all evaluated organs and targets. Gamma evaluation showed a mean pass rate of 99.12% (0.63%, 1 SD) in the complete body volume and 99.97% (0.13%, 1 SD) in the planning target volume using a 2%/ 2-mm global gamma criteria.Conclusions: Results of the study show that the sCT conversion method can be used clinically, with minimal differences between sCT and CT dose distributions for target and relevant organs at risk. The small differences seen are consistent between centers, indicating that an MR imagingeonly workflow using MriPlanner is robust for a variety of field strengths, vendors, and treatment techniques.
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| 28. |
- Sandels, Claes, 1985-, et al.
(författare)
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Day-Ahead Predictions of Electricity Consumption in a Swedish Office Building from Weather, Occupancy, and Temporal data
- 2015
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Ingår i: Energy and Buildings. - : Elsevier. - 0378-7788 .- 1872-6178. ; 108
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Tidskriftsartikel (refereegranskat)abstract
- An important aspect of Demand Response (DR) is to make accurate predictions for the consumption in the short term, in order to have a benchmark load profile which can be compared with the load profile influenced by DR signals. In this paper, a data analysis approach to predict electricity consumption on load level in office buildings on a day-ahead basis is presented. The methodology is: (i) exploratory data analysis, (ii) produce linear models between the predictors (weather and occupancies) and the outcomes (appliance, ventilation, and cooling loads) in a step wise function, and (iii) use the models from (ii) to predict the consumption levels with day-ahead prognosis data on the predictors. The data has been collected from a Swedish office building floor. The results from (ii) show that occupancy is correlated with appliance load, and outdoor temperature and a temporal variable defining work hours are connected with ventilation and cooling load. It is concluded from the results in (iii) that the error rate decreases if fewer predictors are included in the predictions. This is because of the inherent forecast errors in the day-ahead prognosis data. The achieved error rates are comparable with similar prediction studies in related work.
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| 29. |
- Sandels, Claes, et al.
(författare)
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Forecasting household consumer electricity load profiles with a combined physical and behavioral approach
- 2014
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Ingår i: Applied Energy. - : Elsevier BV. - 0306-2619 .- 1872-9118. ; 131, s. 267-278
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, a simulation model that forecasts electricity load profiles for a population of Swedish households living in detached houses is presented. The model is constructed of three separate modules, namely appliance usage, Domestic Hot Water (DHW) consumption and space heating. The appliance and DHW modules are based on non-homogenous Markov chains, where household members move between different states with certain probabilities over the days. The behavior of individuals is linked to various energy demanding activities at home. The space heating module is built on thermodynamical aspects of the buildings, weather dynamics, and the heat loss output from the aforementioned modules. Subsequently, a use case for a neighborhood of detached houses in Sweden is simulated using a Monte Carlo approach. For the use case, a number of justified assumptions and parameter estimations are made. The simulations results for the Swedish use case show that the model can produce realistic power demand profiles. The simulated profile coincides especially well with the measured consumption during the summer time, which confirms that the appliance and DHW modules are reliable. The deviations increase for some periods in the winter period due to, e.g. unforeseen end-user behavior during occasions of extreme electricity prices.
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| 30. |
- Sandels, Claes, et al.
(författare)
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Modeling office building consumer load with a combined physical and behavioral approach: Simulation and validation
- 2016
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Ingår i: Applied Energy. - : Elsevier. - 0306-2619 .- 1872-9118. ; 162, s. 472-485
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Tidskriftsartikel (refereegranskat)abstract
- Summary: Due to an expanding integration of renewable energy resources in the power systems, mismatches between electricity supply and demand will increase. A promising solution to deal with these issues is Demand Response (DR), which incentives end-users to be flexible in their electricity consumption. This paper presents a bottom up simulation model that generates office building electricity load profiles representative for Northern Europe. The model connects behavioral aspects of office workers with electricity usage from appliances, and physical representation of the building to describe the energy use of the Heating Ventilation and Air Conditioning systems. To validate the model, simulations are performed with respect to two data sets, and compared with real load measurements. The validation shows that the model can reproduce load profiles with reasonable accuracy for both data sets. With the presented model approach, it is possible to define simple portfolio office building models which subsequently can be used for simulation and analysis of DR in the power systems.
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| 31. |
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| 32. |
- Siversson, Carl, et al.
(författare)
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Technical Note : MRI only prostate radiotherapy planning using the statistical decomposition algorithm
- 2015
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Ingår i: Medical physics (Lancaster). - : Wiley. - 0094-2405. ; 42:10, s. 6090-6097
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: In order to enable a magnetic resonance imaging (MRI) only workflow in radiotherapy treatment planning, methods are required for generating Hounsfield unit (HU) maps (i.e., synthetic computed tomography, sCT) for dose calculations, directly from MRI. The Statistical Decomposition Algorithm (SDA) is a method for automatically generating sCT images from a single MR image volume, based on automatic tissue classification in combination with a model trained using a multimodal template material. This study compares dose calculations between sCT generated by the SDA and conventional CT in the male pelvic region. Methods: The study comprised ten prostate cancer patients, for whom a 3D T2 weighted MRI and a conventional planning CT were acquired. For each patient, sCT images were generated from the acquired MRI using the SDA. In order to decouple the effect of variations in patient geometry between imaging modalities from the effect of uncertainties in the SDA, the conventional CT was nonrigidly registered to the MRI to assure that their geometries were well aligned. For each patient, a volumetric modulated arc therapy plan was created for the registered CT (rCT) and recalculated for both the sCT and the conventional CT. The results were evaluated using several methods, including mean average error (MAE), a set of dose-volume histogram parameters, and a restrictive gamma criterion (2% local dose/1 mm). Results: The MAE within the body contour was 36.5 +/- 4.1 (1 s.d.) HU between sCT and rCT. Average mean absorbed dose difference to target was 0.0% +/- 0.2% (1 s.d.) between sCT and rCT, whereas it was -0.3% +/- 0.3% (1 s.d.) between CT and rCT. The average gamma pass rate was 99.9% for sCT vs rCT, whereas it was 90.3% for CT vs rCT. Conclusions: The SDA enables a highly accurate MRI only workflow in prostate radiotherapy planning. The dosimetric uncertainties originating from the SDA appear negligible and are notably lower than the uncertainties introduced by variations in patient geometry between imaging sessions.
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| 33. |
- Thorgren, Sara, et al.
(författare)
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Hybrid entrepreneurs' second-step choice : the nonlinear relationship between age and intention to enter full-time entrepreneurship
- 2016
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Ingår i: Journal of Business Venturing Insights. - : Elsevier BV. - 2352-6734. ; 5, s. 14-18
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Tidskriftsartikel (refereegranskat)abstract
- Entrepreneurs who run venture startups parallel to wage employment engage in so-called hybrid entrepreneurship. Not all hybrid entrepreneurs, however, eventually leave the wage employment to become a full-time entrepreneur (second-step entrepreneurship). Significant research has focused on first-step entrepreneurial choice (to engage in a business start-up), but much less has focused on a second-step entrepreneurial choice, which captures the transition to full-time entrepreneurship. The present study, which examines the second-step entrepreneurial choice, reveals a U-shaped relationship be- tween age and the intention to enter full-time entrepreneurship. Interestingly, this con- trasts with prior studies on the effects from age in the first-step entrepreneurship choice, demonstrating an inverted U-relationship between age and venture startup.
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| 34. |
- Thorgren, Sara, et al.
(författare)
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Hybrid entrepreneurship : the importance of passion
- 2014
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Ingår i: Baltic Journal of Management. - 1746-5265 .- 1746-5273. ; 9:3, s. 314-329
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Tidskriftsartikel (refereegranskat)abstract
- Purpose – The purpose of this paper is to investigate the motives behind individuals’ choice to haveparallel business-employment careers (hybrid entrepreneurship) with a particular focus on passion(i.e. to work with something one is passionate about) as the main motive.Design/methodology/approach – A survey was administered to 262 Swedish hybridentrepreneurs. Hypotheses proposed associations of the individual’s age at business start-up andweekly hours spent on the business with passion as the main motive for the hybrid form. Logisticregression was used to test the hypotheses.Findings – The results indicated that first, the ability to work with something one is passionate aboutis the top motive for combining employment with a side business; second, passion is more likely to bethe main motive behind the hybrid form among individuals who are older at business start-up; third,passion is less likely to be the main motive behind the hybrid form among individuals who spend moretime on the business.Research limitations/implications – The study focusses on passion as motive for hybridentrepreneurship, and in doing so, it does not test the extent to which hybrid entrepreneurs experiencepassion.Practical implications – The results support the popular notion that passion drives people to haveparallel business-employment careers. Findings indicating that passion as a motive is more commonamong those who are older at start-up and less common among those who spend more time onthe business suggest the importance of acknowledging hybrid entrepreneurs’ various profiles whenapproaching them in research and practice.Originality/value – This is the first study on motives behind hybrid entrepreneurship.
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| 35. |
- Von Würtemberg, Liv Marcks, et al.
(författare)
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IT project success factors : An experience report
- 2011
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Ingår i: Portland International Center for Management of Engineering and Technology. - 1890843245 - 9781890843243
-
Konferensbidrag (refereegranskat)abstract
- Large investments are made annually for development and maintenance ofITsystems, systems that support the core business of all types of companies and organizations. Successful outcome ofITprojectsis therefore a crucial issue for the economy at large, yet a majority of theITprojectscarried out today fail whenitcomes to finishing on time, within budget and with the desired quality. The contribution of this paper is theexperiencefrom 28ITprojects. The influence ofITprojectsuccessfactors, derived from previous research, were assessed by theprojectmanagers and compared with theprojectsoutcome in terms of time, budget and quality. Though the dataset is too small to allow generalization, thesuccessfactorsRisk analysis, User involvement and Top management support turned out to be of particular importance for the reviewedprojects.
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| 36. |
- Westerlund, Joakim, et al.
(författare)
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Breaks in persistence in fixed-T panel data
- 2021
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Ingår i: Economics Letters. - : Elsevier BV. - 0165-1765. ; 205
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Tidskriftsartikel (refereegranskat)abstract
- This paper considers an autoregressive panel data model in which the autoregressive coefficient has undergone a structural break. The object of interest is the unknown breakpoint. A least squares-based estimator is proposed that is shown to be consistent when only the number of cross-section units, N, is large and the number of time periods, T, is small, thereby enabling quick detection of the onset of a new regime.
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| 37. |
- Wolkerstorfer, Martin, et al.
(författare)
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Column generation for discrete-rate multi-user and multi-carrier power control
- 2012
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Ingår i: IEEE Transactions on Communications. - Piscataway : IEEE Press. - 0090-6778 .- 1558-0857. ; 60:9, s. 2712-2722
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Tidskriftsartikel (refereegranskat)abstract
- We consider a constrained multi-carrier power allocation problem in interference-limited multi-user systems with a finite set of transmission rates. The Lagrange relaxation is a common technique for decomposing such problems into independently solvable per-subcarrier problems. Deviating from this approach our main contribution is the proposal of a novel spectrum management framework based on a Nonlinear Dantzig-Wolfe problem decomposition. It allows for suboptimal initialization and suboptimal power allocation methods with low complexity. While we show that the combinatorial per-subcarrier problems have polynomial complexity in the number of users, we find that such suboptimal methods are indispensable in large systems. Thus we give an overview of various basic dual heuristics and provide simulation results on a set of thousand digital subscriber line (DSL) networks which show the superior performance of our framework compared to previous power control algorithms.
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| 38. |
- Wolkerstorfer, Martin, et al.
(författare)
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Low-complexity optimal discrete-rate spectrum balancing in digital subscriber lines
- 2013
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Ingår i: Signal Processing. - Amsterdam : Elsevier. - 0165-1684 .- 1872-7557. ; 93:1, s. 23-34
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Tidskriftsartikel (refereegranskat)abstract
- Discrete-rate spectrum balancing in interference-limited multi-user and multi-carrier digital subscriber lines (DSL) is a large-scale, non-convex and combinatorial problem. Previously proposed algorithms for its (dual) optimal solution are only applicable for networks with few users, while the suboptimality of less complex bit-loading algorithms has not been adequately studied so far. We deploy constrained optimization techniques as well as problem-specific branch-and-bound and search-space reduction methods, which for the first time give a low-complexity guarantee of optimality in certain multi-user DSL networks of practical size. Simulation results precisely quantify the suboptimality of multi-user bit-loading schemes in a thousand ADSL2 scenarios under measured channel data.
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