| 1. |
- Kjellström, Sofia, 1970-, et al.
(författare)
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Exploring, measuring and enhancing the coproduction of health and well-being at the national, regional and local levels through comparative case studies in Sweden and England : the 'Samskapa' research programme protocol
- 2019
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Ingår i: BMJ Open. - : BMJ Publishing Group Ltd. - 2044-6055. ; 9:7
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION:Cocreation, coproduction and codesign are advocated as effective ways of involving citizens in the design, management, provision and evaluation of health and social care services. Although numerous case studies describe the nature and level of coproduction in individual projects, there remain three significant gaps in the evidence base: (1) measures of coproduction processes and their outcomes, (2) mechanisms that enable inclusivity and reciprocity and (3) management systems and styles. By focusing on these issues, we aim to explore, enhance and measure the value of coproduction for improving the health and well-being of citizens.METHODS AND ANALYSIS:Nine ongoing coproduction projects form the core of an interactive research programme ('Samskapa') during a 6-year period (2019-2024). Six of these will take place in Sweden and three will be undertaken in England to enable knowledge exchange and cross-cultural comparison. The programme has a longitudinal case study design using both qualitative and quantitative methods. Cross-case analysis and a sensemaking process will generate relevant lessons both for those participating in the projects and researchers. Based on the findings, we will develop explanatory models and other outputs to increase the sustained value (and values) of future coproduction initiatives in these sectors.ETHICS AND DISSEMINATION:All necessary ethical approvals will be obtained from the regional Ethical Board in Sweden and from relevant authorities in England. All data and personal data will be handled in accordance with General Data Protection Regulations. Given the interactive nature of the research programme, knowledge dissemination to participants and stakeholders in the nine projects will be ongoing throughout the 6 years. External workshops-facilitated in collaboration with participating case studies and citizens-both during and at the end of the programme will provide an additional dissemination mechanism and involve health and social care practitioners, policymakers and third-sector organisations.
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| 2. |
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| 3. |
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| 4. |
- Andersson, Joakim, 1966, et al.
(författare)
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Brobygge i lärandesituationer under slöjdarbete
- 2016
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Ingår i: NÄD2016, Nationell Ämnesdidaktisk Konferens 19-21 april 2016. Malmö.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Syftet med denna presentation är att diskutera hur samspelet mellan lärarstudenter, lärare och omgivning medverkar i lärandesituationer för att utveckla händig- och skicklighet under slöjdarbete. Under studenternas utbildning till att bli lärare för skolans slöjdämne ingår det under utbildningstiden också arbeten i verkstäder för att öva upp skicklighet och bli kunnig i hantverket med att forma slöjdföremål. För att som utbildad slöjdlärare kunna undervisa i skolans slöjdämne är det angeläget att själv ha fått erfarenheter i hur det succesivt kan gå till att lära sig slöjda. Videoinspelad empiri är insamlad under två dagars workshop i svarvning vid en slöjdlärarutbildning. De inspelade slöjdaktiviteterna utmärks av att de studerande samordnar sina aktivitetet med stöd av både verbal och icke verbalt kommunikation. Hur samspel bygger broar när lärprocesser formas genom instruktioner och intryck när studenterna utvecklar sin kunnighet och skicklighet är av intresse att utforska. Vi vill diskutera hur kunnande formas i interaktion med personer och omgivning när studenter lär sig forma slöjdföremål med hjälp av redskap och material. Vad är det som gör att personen växlar mellan att arbeta själv eller få hjälp av andra? Hur utvecklas studenternas lärprocesser genom samtal och andra kommunikationsformer (kroppsspråk, gester, mimik, handlingar, etc.) för att de ska bli mer kunniga, skickliga och konstfarna i slöjdarbetet? Hur används instruktioner och intryck i lärprocessen?
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| 5. |
- Andersson, Joakim, 1966, et al.
(författare)
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Händig, skicklig och konstfärdig – slöjdkunnande i interaktion
- 2017
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Ingår i: Forskning om undervisning och lärande. - 2001-6131. ; 5:1, s. 26-46
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Tidskriftsartikel (refereegranskat)abstract
- Skolans slöjdundervisning erbjuder ett lärande som skiljer sig i förhållande till flera skolämnen då kunskaperna utvecklas och synliggörs genom att tillverka ett fysiskt föremål. I läroplanstexter beskrivs slöjdämnet och vad eleverna förväntas utveckla, men det finns få praktiknära forskningsstudier om hur det kan gå till att lära sig slöjda. Innebörden av begreppet slöjd är mångfasetterad och det kan vara problematiskt att uppfatta skillnader i slöjdens lärprocesser. Att bli mer händig, skicklig och konstfärdig i att forma slöjdföremål kan uppfattas som ’praktiskt arbete’ i allmänhet, kunnandet kan förbli dolt i oreflekterat görande. I föreliggande studie har en workshop i träsvarvning på en slöjdlärarutbildning studerats. Syftet är att undersöka slöjdkunnighet och beskriva hur slöjdkunnande konstitueras i interaktion med andra och med de situationer som skapas i den fysiska miljön för slöjdverksamheten. De videofilmade situationerna har analyserats utifrån några av slöjdbegreppens betydelser; händig, skicklig och konstfärdig. Utöver hantverkskunnande synliggör studien pedagogiska aspekter om hur det kan gå till att lära sig slöjda. Analyserna visar att slöjdarbete inte bara handlar om att arbeta på ett eget slöjdföremål. Studenterna intar olika roller när de, med hjälp av flera multimodala resurser, arbetar på både egna och varandras arbeten.
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| 6. |
- Andersson, Joakim, 1966, et al.
(författare)
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Learning situations in Sloyd
- 2016
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Ingår i: International NordFo Conference in Rauma, Finland, Sept. 28-30, 2016. ; 2016
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Learning situations in Sloyd. The aim of this presentation is to discuss how the interaction between students within the teacher education, teachers and the environment are involved in learning situations to develop dexterity and skills within Sloyd [Slöjd]. During the students' education to become teachers for the school subject Sloyd time in workshops are included to practice skills and be knowledgeable in the crafting of sloyd objects. To be able to teach as an educated teacher within sloyd it is important to have the experience of gradually learning how to learn to craft in sloyd. Video Recorded empirical data is collected during a two-day workshop in turning at a teacher education programme. The recorded crafts activities are characterized by the students’ coordination of their activities by the use of both verbal and non-verbal communication. It is of interest to explore how learning processes are formed by instructions and impressions when the students develop their knowledge and skills. We would like to discuss how knowledge is formed in interaction with people and the environment when students learn how to shape the craft objects by using tools and materials. What is it that makes a person alternate between working by oneself or receiving help from others? How are students’ learning processes developed through conversations and other forms of communication (body language, gestures, facial expressions, actions, etc.) to make them more knowledgeable in their craft, skillful and proficient in the work of forming a crafted artefact? How are instructions and impressions used during the learning process?
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| 7. |
- Andersson, Joakim, 1966, et al.
(författare)
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Learning situations in Sloyd ‒ to become more handy, dexterous and skilful
- 2017
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Ingår i: Techne series : Research in sloyd education and crafts science. A. - 1238-9501 .- 1893-1774. ; 24:2, s. 93-109
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Tidskriftsartikel (refereegranskat)abstract
- This article provides examples of how students in a teacher training course in sloyd [sw. slöjd] develop their knowledge of sloyd during a workshop in woodturning. Several names from the definition of sloyd may be perceived as relatively the same, but in this article is the focus on three of the meanings included in the concept sloyd; handy [sw. händig], dexterous [sw. hantverksskicklig] and skilful in forming a crafted artefact [sw. konstfärdig]. It is of interest to explore how such skills, usually ‘hidden’ in the making processes, can be developed in learning processes. The study aims to describe how the sloyd skill develops in interaction with others and with the situations created in the physical environment during sloyd activities. The study, carried out by video documentation and microanalysis, shows that so-called practical knowledge requires support from several multimodal forms of interactions. From the video material, three sequences of microanalysis have been selected for this article. The results show that learning to do sloydwork is not something that takes place by only working on one’s own object. The students alternate between standing by and watch, or practice, or demonstrated, their skills when they work on each other's object. Body language and actions have an important role in how shared understanding is created for how for example the suitable handling of a woodturning tool should be implemented. The embedded meanings in the sloyd concept used in this article ‒ handy, dexterous and skilful in forming a crafted artefact ‒ show that knowledge of sloyd includes handicraft knowledge as well as pedagogic aspects.
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| 8. |
- Andersson, Joakim, 1966, et al.
(författare)
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Samtal och meningsskapande i slöjdklassrum
- 2019
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Ingår i: Samtal och meningsskapande i slöjdklassrum (Skolverkets lärportal. Modul: Muntlig kommunikation. Perspektiv på muntlig kommunikation). - Stockholm : Skolverket. ; Del 7, s. 1-9
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Att det ”pratas mycket” under slöjdarbetet är något som eleverna uttryckt som positivt i slöjdforskning och i nationella utvärderingar av slöjdämnet. Elever menar att det är bra ”att man får prata och arbeta på samma gång i slöjden”. Utöver de samtal läraren har inför alla elever vid till exempel genomgångar och redovisningar inbjuder slöjd till nära kommunikation mellan läraren och eleverna under arbetet med material, redskap och slöjdföremål – både muntligt, kroppsligt och visuellt. Men frågor kan ställas om hur slöjdlärare på bästa sätt kan medverka för att lyfta språkutvecklande aspekter i samtalen. I artikeln betraktas slöjdämnets muntliga kommunikation utifrån tre utgångspunkter: Kommunikativa förhållningssätt; Lärares förhållningssätt i slöjdundervisningen, och Fiktiva och konkreta kommunikationsformer. Därefter diskuteras meningsskapanden och uttryck i slöjdundervisning. Artikeln avslutas med några didaktiska reflektioner.
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| 9. |
- Andersson, Marlene, et al.
(författare)
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Biomimetic spinning of artificial spider silk from a chimeric minispidroin
- 2017
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Ingår i: Nature Chemical Biology. - : Nature Publishing Group. - 1552-4450 .- 1552-4469. ; 13:3, s. 262-
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Tidskriftsartikel (refereegranskat)abstract
- Herein we present a chimeric recombinant spider silk protein (spidroin) whose aqueous solubility equals that of native spider silk dope and a spinning device that is based solely on aqueous buffers, shear forces and lowered pH. The process recapitulates the complex molecular mechanisms that dictate native spider silk spinning and is highly efficient; spidroin from one liter of bacterial shake-flask culture is enough to spin a kilometer of the hitherto toughest as-spun artificial spider silk fiber.
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| 10. |
- Andersson, Marlene, et al.
(författare)
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Biomimetic spinning of artificial spider silk from a chimeric minispidroin
- 2017
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Ingår i: Nature Chemical Biology. - : Springer Science and Business Media LLC. - 1552-4450 .- 1552-4469. ; 254
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Tidskriftsartikel (refereegranskat)abstract
- Herein we present a chimeric recombinant spider silk protein (spidroin) whose aqueous solubility equals that of native spider silk dope and a spinning device that is based solely on aqueous buffers, shear forces and lowered pH. The process recapitulates the complex molecular mechanisms that dictate native spider silk spinning and is highly efficient; spidroin from one liter of bacterial shake-flask culture is enough to spin a kilometer of the hitherto toughest as-spun artificial spider silk fiber.
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| 11. |
- Andersson, Marlene, et al.
(författare)
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Carbonic Anhydrase Generates CO2 and H+ That Drive Spider Silk Formation Via Opposite Effects on the Terminal Domains
- 2014
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Ingår i: PLoS biology. - : Public Library of Science (PLoS). - 1544-9173 .- 1545-7885. ; 12:8, s. e1001921-
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Tidskriftsartikel (refereegranskat)abstract
- Spider silk fibers are produced from soluble proteins (spidroins) under ambient conditions in a complex but poorly understood process. Spidroins are highly repetitive in sequence but capped by nonrepetitive N- and C-terminal domains (NT and CT) that are suggested to regulate fiber conversion in similar manners. By using ion selective microelectrodes we found that the pH gradient in the silk gland is much broader than previously known. Surprisingly, the terminal domains respond in opposite ways when pH is decreased from 7 to 5: Urea denaturation and temperature stability assays show that NT dimers get significantly stabilized and then lock the spidroins into multimers, whereas CT on the other hand is destabilized and unfolds into ThT-positive beta-sheet amyloid fibrils, which can trigger fiber formation. There is a high carbon dioxide pressure (pCO(2)) in distal parts of the gland, and a CO2 analogue interacts with buried regions in CT as determined by nuclear magnetic resonance (NMR) spectroscopy. Activity staining of histological sections and inhibition experiments reveal that the pH gradient is created by carbonic anhydrase. Carbonic anhydrase activity emerges in the same region of the gland as the opposite effects on NT and CT stability occur. These synchronous events suggest a novel CO2 and proton-dependent lock and trigger mechanism of spider silk formation.
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| 12. |
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| 13. |
- Andersson, Marlene
(författare)
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Mechanisms of native and artificial spinning of spider silk
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Spider silk is tougher than all other known natural and man-made fibers, and represents an environmentally friendly material that could potentially be used for many different purposes, ranging from biomaterials to construction materials. However, for large-scale production of silk, methods to produce artificial silk fibers must be developed. In this thesis, the molecular mechanisms of silk spinning were studied with the aim of developing a biomimetic method for production of artificial spider silk fibers. Major ampullate glands of spiders were studied using light and transmission electron microscopy. Three different epithelial cell types were identified in the tail and sac, two of which produce spider silk proteins (spidroins) that make up the silk and one of which produces carbonic anhydrase that maintains a pH gradient along the gland. The pH gradient was determined to go from pH 7.6 in the tail to pH 5.7 halfway along the duct. Silkworm silk glands were also shown to contain several different epithelial cell types and it was determined that carbonic anhydrase maintains a pH gradient from 8.2 to 6.2 along the gland. Spidroins consist of a repetitive region with alternating poly-alanine blocks and glycine-rich repeats, flanked by highly conserved globular domains, the N-terminal (NT) and C-terminal (CT) domain. Recombinant versions of NT and CT were studied under the conditions found in the major ampullate gland, and were shown to regulate fiber formation by responding to pH in coordinated but opposite ways, following a lock and trigger mechanism. While NT gets more stable and dimerizes as pH is lowered, and thereby interconnects the spidroins into large networks (lock), CT is destabilized, unfolds and turns into β-sheet amyloid-like fibrils in response to low pH and high pCO2, which may nucleate further β-sheet formation of the repetitive region (trigger). Based on the knowledge generated on native silk spinning, a biomimetic method to spin artificial spider silk fibers was developed. A chimeric recombinant spidroin was designed by combining a highly soluble NT and CT with a short repetitive region. The extremely soluble spidroin could be concentrated to unprecedented levels, and formed tough, kilometer-long fibers upon spinning into a low pH aqueous buffer.
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| 14. |
- Andersson, Marlene, et al.
(författare)
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Morphology and Composition of the Spider Major Ampullate Gland and Dragline Silk
- 2013
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Ingår i: Biomacromolecules. - : American Chemical Society (ACS). - 1525-7797 .- 1526-4602. ; 14, s. 2945-2952
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Tidskriftsartikel (refereegranskat)abstract
- Spider silk is made of unique proteins-spidroins-secreted and stored as a protein solution (dope) in specialized glands. The major ampullate gland, source of the dragline silk, is composed of a tail, a sac and an elongated duct. For this gland, several different types of epithelial cells and granules have been described, but it is largely unknown how they correlate with spidroin production. It is also not settled what parts of the large spidroins end up in the final silk, and it has been suggested that the N-terminal domain (NT) is lacking. Here we show that NT is present in the dope and throughout drag,line silk fibers, including the skin layer, and that the major ampullate tail and sac consist of three different and sharply demarcated zones (A-C), each with a distinct epithelial cell type. Finally, we show that spidroins are produced in the A and B zone epithelia, while the C zone granules lack spidroins.
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| 15. |
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| 16. |
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| 17. |
- Andersson, Marlene, et al.
(författare)
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Silk Spinning in Silkworms and Spiders
- 2016
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Ingår i: International Journal of Molecular Sciences. - : MDPI AG. - 1661-6596 .- 1422-0067. ; 17
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Forskningsöversikt (refereegranskat)abstract
- Spiders and silkworms spin silks that outcompete the toughness of all natural and manmade fibers. Herein, we compare and contrast the spinning of silk in silkworms and spiders, with the aim of identifying features that are important for fiber formation. Although spiders and silkworms are very distantly related, some features of spinning silk seem to be universal. Both spiders and silkworms produce large silk proteins that are highly repetitive and extremely soluble at high pH, likely due to the globular terminal domains that flank an intermediate repetitive region. The silk proteins are produced and stored at a very high concentration in glands, and then transported along a narrowing tube in which they change conformation in response primarily to a pH gradient generated by carbonic anhydrase and proton pumps, as well as to ions and shear forces. The silk proteins thereby convert from random coil and alpha helical soluble conformations to beta sheet fibers. We suggest that factors that need to be optimized for successful production of artificial silk proteins capable of forming tough fibers include protein solubility, pH sensitivity, and preservation of natively folded proteins throughout the purification and initial spinning processes.
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| 18. |
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| 19. |
- Andersson, Åke, et al.
(författare)
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Status of the new injector for MAX-lab
- 2002
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Ingår i: 8th European Particle Accelerator Conference. ; , s. 772-774
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Konferensbidrag (refereegranskat)abstract
- The new injector for MAX-lab is built around two 125 MeV linacs [B. Anderberg, (2000)] equipped with SLED cavities [Z.D. Farkas, (1974)]. The electron beam is recirculated once to reach 500 MeV. A 2.3 MeV thermionic RF gun [B. Anderberg, (2000)] injects into the system. The RF-gun is put into operation and commissioning of the first linac is proceeding. Results from the thermionic RF-gun operation, linac commissioning and first beam operations are presented.
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| 20. |
- Andersson, Åke, et al.
(författare)
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The 100 MHz RF system for MAX-II and MAX-III
- 2002
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Ingår i: 8th European Particle Accelerator Conference. ; , s. 2118-2120
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Konferensbidrag (refereegranskat)abstract
- The MAX-II synchrotron radiation source has since 1997 been operated routinely with a double RF system, 500 MHz active plus 1.5 GHz passive. Four Landau cavities have successfully provided increased Touschek beam lifetime, and damping of coupled bunch mode instabilities. However, the delivered power from the present 500 MHz RF system will be marginal for the operation of the planned MAX-II SC wigglers, with 250 mA circulating beam current. It is shown that it is favourable to change to a 100 MHz system, with one 500 MHz Landau cavity, both considering power consumption, beam lifetime and beam stability. The new RF system and the cavities, that are being built at MAX-lab, are described. The same RF combination and type of cavities will be used at the VUV source MAX-III
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| 21. |
- Andersson, Åke, et al.
(författare)
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The MAX IV facility
- 2004
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Ingår i: European Particle Accelerator Conference, EPAC2004, Lucerne, Switzerland.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 22. |
- Andree, Maria, et al.
(författare)
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Knowledge Products from Close-To-Practice Research
- 2024
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Ingår i: Round table presentation at the NERA-conference, 6-8 March, Malmö University.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- ‘Close-to-practice research’ has received increased attention across the Nordic countries. Following the British Education Research Association (BERA), the notion of ‘close-to-practice research’ is used to refer to educational research that is based on problems in practice, often involves researchers working in partnership with practitioners in schools and addresses issues of relevance to practitioners. This roundtable focuses on how close-to-practice research can contribute to the knowledge base of the teaching profession by bringing together perspectives from didactics, school improvement and educational policy. More specifically, the interest is directed toward what characterizes the knowledge produced through practice-based research that may have significance for teachers' professional knowledge base and practice. The roundtable conversation builds on a previous analysis of what kinds of knowledge products are generated in didactic close-to-practice research where teachers and researchers work together within the research environment Stockholm Teaching & Learning Studies. As a result of this analysis a typology of knowledge products was proposed including: (i) descriptions of knowing, (ii) teaching design, (iii) didactic examples and (iv) methodological tools. It has been proposed that additional knowledge products may be developed, such as artifacts to be used in teaching (e.g. lesson plans, visual representations). The roundtable will include the following points of discussion: 1) a brief presentation of the typology, 2) challenging and developing the typology of knowledge products proposed by previous research by investigating different cases of close-to-practice research from traditions of action research and practice-developing research within subject-didactics, and 3) discussing how the notion of knowledge products may contribute to advancing the conversation on cumulativity in the field of educational research in general, and in relation to syntheses of close-to-practice research in particular. The participants will be engaged in conversations on the desirability and feasibility of striving towards cumulativity.
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| 23. |
- Bergman, Hilde-Marléne, et al.
(författare)
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Quantitative mass spectrometry imaging of small-molecule neurotransmitters in rat brain tissue sections using nanospray desorption electrospray ionization
- 2016
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Ingår i: The Analyst. - : Royal Society of Chemistry (RSC). - 0003-2654 .- 1364-5528. ; 141:12, s. 3686-3695
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Tidskriftsartikel (refereegranskat)abstract
- Small molecule neurotransmitters are essential for the function of the nervous system, and neurotransmitter imbalances are often connected to neurological disorders. The ability to quantify such imbalances is important to provide insights into the biochemical mechanisms underlying the disorder. This proof-of-principle study presents online quantification of small molecule neurotransmitters, specifically acetylcholine, γ-aminobutyric acid (GABA) and glutamate, in rat brain tissue sections using nanospray desorption electrospray ionization (nano-DESI) mass spectrometry imaging. By incorporating deuterated internal standards in the nano-DESI solvent we show identification, accurate mapping, and quantification of these small neurotransmitters in rat brain tissue without introducing any additional sample preparation steps. We find that GABA is about twice as abundant in the medial septum-diagonal band complex (MSDB) as in the cortex, while glutamate is about twice as abundant in the cortex as compared to the MSDB. The study shows that nano-DESI is well suited for imaging of small molecule neurotransmitters in health and disease.
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| 24. |
- Bonmann, Marlene, 1988, et al.
(författare)
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An Integrated 200-GHz Graphene FET Based Receiver
- 2018
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Ingår i: International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz. - 2162-2027 .- 2162-2035. ; 2018-September
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Konferensbidrag (refereegranskat)abstract
- A receiver composed by a graphene FET 200-GHz mixer and a 1-GHz intermediate frequency amplifier integrated on a silicon substrate was modelled, fabricated and characterized. This is the first demonstration of a millimeter wave integrated receiver based on graphene FETs. The receiver conversion loss is measured to be 25 dB across the 185-205-GHz band with 16 dBm of local oscillator pump power, which is in good agreement with the circuit simulations. The simulations show that the receiver conversion loss can be significantly reduced to 16 dB by reducing the contact resistance and by realizing a higher charge carrier mobility in the mixer transistor.
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| 25. |
- Bonmann, Marlene, 1988, et al.
(författare)
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Characterization of Graphene FET based 200 GHz Mixer and 1 GHz Amplifier Integrated on a Si Substrate
- 2018
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- arises for new materials and technologies which can be used in the millimeter wave and terahertz wave regime. In this context, a receiver is an important component to be developed. It converts the received signals into useful information. A typical heterodyne receiver consists of an antenna, RF and IF filters, RF and IF amplifiers, and a mixer. The amplifiers and the mixer can be based on field effect transistors (FETs). To obtain high speed transistors the charge carrier mobility and velocity in the transistor channel should be high. Therefore, the 2D material graphene is an interesting material since it has a high room temperature charge carrier mobility and a high saturation velocity [1]. In previous works a 10 dB small-signal amplifier designed for 1 GHz [2] and a 185-215 GHz subharmonic resistive mixer [3] (designed for a center frequency at 200 GHz) based on graphene FETs (GFETs) have been demonstrated. The amplifier was further developed in [4] and the lumped inductor for matching used in [2] was replaced by an planar inductor. The measured and modeled gain for the two inductor types are shown in Fig. 1. The gain is reduced from 10 dBm to 5 dBm when using the planar inductor compared to the lumped inductor. The model shows that the gain can be increased to the designed gain of 10 dBm if the inductor resistance is reduced to Rs =5 by increasing the thickness of the gold conductor to 2 m. Additionally, the mixer design in [3] has been improved compared to the mixer design in [5] by decreasing the loss in the coplanar waveguid (CPW) circuit using air bridges. In this work, both, the amplifier and mixer are integrated together on a single silicon substrate and the characterization results are presented.
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| 26. |
- Bonmann, Marlene, 1988, et al.
(författare)
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Charge carrier velocity in graphene field-effect transistors
- 2017
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 111:23, s. 233505-
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Tidskriftsartikel (refereegranskat)abstract
- To extend the frequency range of transistors into the terahertz domain, new transistor technologies, materials, and device concepts must be continuously developed. The quality of the interface between the involved materials is a highly critical factor. The presence of impurities can degrade device performance and reliability. In this paper, we present a method that allows the study of the charge carrier velocity in a field-effect transistor vs impurity levels. The charge carrier velocity is found using high-frequency scattering parameter measurements followed by delay time analysis. The limiting factors of the saturation velocity and the effect of impurities are then analysed by applying analytical models of the field-dependent and phonon-limited carrier velocity. As an example, this method is applied to a top-gated graphene field-effect transistor (GFET). We find that the extracted saturation velocity is ca. 1.4×10^7 cm/s and is mainly limited by silicon oxide substrate phonons. Within the considered range of residual charge carrier concentrations, charged impurities do not limit the saturation velocity directly by the phonon mechanism. Instead, the impurities act as traps that emit charge carriers at high fields, preventing the current from saturation and thus limiting power gain of the GFETs. The method described in this work helps to better understand the influence of impurities and clarifies methods of further transistor development. High quality interfaces are required to achieve current saturation via velocity saturation in GFETs.
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| 27. |
- Bonmann, Marlene, 1988, et al.
(författare)
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Delay analysis for evaluation of carrier velocity in graphene field-effect transistors
- 2017
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Ingår i: Graphene Week 2017, Athens, Greece, 25-29 September, 2017.
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Konferensbidrag (refereegranskat)abstract
- One of the main challenges in the development of graphene field-effect transistors (GFETs) forapplications in high frequency electronics is achieving high maximum frequency of oscillation (fmax),which is the power gain parameter. A promising way to achieve higher fmax is drain current saturationvia saturation of the charge carrier velocity at high electric fields [1]. Therefore, accurate evaluation ofthe charge carrier velocity in GFETs, and its field dependence, are of importance. In this work, a methodis presented that allows for the evaluation and analysis of the carrier velocity in GFETs via delay timeanalysis using measured cut-off frequencies. The measured cut-off frequency is inversely proportionalto the total delay time, which, in GFETs on Si substrates, can be expressed as the sum of intrinsic andextrinsic delay times [2, 3, 4]. The intrinsic delay is defined by the transit time, i.e. the time taken by thecharge carriers to travel across the channel, which is related to the carrier velocity. The extrinsic delaysare charging delays, i.e. RC time constants required to charge and discharge the parasitic parts of theGFETs, associated with contact resistance and gate pad capacitance. In order to evaluate the extrinsicdelays the contact resistance and gate pad capacitance are found. The contact resistance is found byapplying a drain resistance fitting model on the measured GFET transfer characteristics. The gate padcapacitance is calculated using the corresponding delay time, which is found as difference between thetotal delay and the delay in the GFETs with virtual infinite gate width W (i.e. at 1/W=0), as shown inFig. 1 [4]. The intrinsic delay time is found by subtracting the extrinsic delay from the total delay and,subsequently, used to calculate the charge carrier velocity (Fig. 2). The advantage of this method, incomparison with the previously used methods based on analysis of the GFET current-voltagecharacteristics, is that the carrier velocity is calculated directly, using measured cut-off frequency,independently from the carrier concentration, and, thereby, avoiding uncertainties associated with thecarrier generation from traps at high fields. This allows for the accurate evaluation of the charge carriervelocity and its field dependence.
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| 28. |
- Brandin, Mathias, et al.
(författare)
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Experimental experience with a thermionic RF-gun
- 2004
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Ingår i: Proceedings of EPAC 2004, Lucerne, Switzerland. - 9290832312 - 9290832320 ; , s. 2394-2396
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 29. |
- Duncan, Kyle D., et al.
(författare)
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A pneumatically assisted nanospray desorption electrospray ionization source for increased solvent versatility and enhanced metabolite detection from tissue
- 2017
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Ingår i: The Analyst. - : ROYAL SOC CHEMISTRY. - 0003-2654 .- 1364-5528. ; 142:18, s. 3424-3431
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Tidskriftsartikel (refereegranskat)abstract
- Nanospray desorption electrospray ionization (nano-DESI) has been established as a powerful technique for mass spectrometry imaging (MSI) of biomolecules from tissue samples. The direct liquid extraction of analytes from a surface at ambient pressure negates the need for significant sample preparation or matrix application. Although many recent studies have applied nano-DESI to new and exciting applications, there has not been much work in the development and improvement of the nano-DESI source. Here, we incorporate a nebulizer to replace the self-aspirating secondary capillary in the conventional nano-DESI setup, and characterize the device by use of rat kidney tissue sections. We find that the pneumatically assisted nano-DESI device offers improved sensitivity for metabolite species by 1-3 orders of magnitude through more complete desolvation and reduced ionization suppression. Further, the pneumatically assisted nano-DESI device reduces the dependence on probe-to-surface distance and enables sampling and imaging using pure water as the nano-DESI solvent. This provides exclusive detection and imaging of many highly polar endogenous species. Overall, the developed pneumatically assisted nano-DESI device provides more versatile solvent selection and an increased sensitivity for metabolites, which generates ion images of higher contrast - allowing for more intricate studies of metabolite distribution.
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| 30. |
- Eksell, Jörgen, et al.
(författare)
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Framtidens möten
- 2024
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Rapport (populärvet., debatt m.m.)abstract
- The Future of Meetings is about new business models, interaction, and communication in the meetings industry. The report examines how the pandemic has affected it and whether the crisis has brought new opportunities.It focuses on changes in the industry's value proposition, how guests in physical, hybrid and digital meetings and conferences interact and the role of hosting and hospitality in these. A good meeting is of great importance for the development of society.in addition, the report contains interviews with Annika Hallman, Head of Meetings, Göteborg & Co and Göteborg Convention Bureau, and Krister Andersson, CEO Umeå Congress.
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| 31. |
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| 32. |
- Kronqvist, Nina, et al.
(författare)
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Sequential pH-driven dimerization and stabilization of the N-terminal domain enables rapid spider silk formation
- 2014
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Ingår i: Nature Communications. - : Nature Publishing Group. - 2041-1723. ; 5:1, s. 3254-
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Tidskriftsartikel (refereegranskat)abstract
- The mechanisms controlling the conversion of spider silk proteins into insoluble fibres, which happens in a fraction of a second and in a defined region of the silk glands, are still unresolved. The N-terminal domain changes conformation and forms a homodimer when pH is lowered from 7 to 6; however, the molecular details still remain to be determined. Here we investigate site-directed mutants of the N-terminal domain from Euprosthenops australis major ampullate spidroin 1 and find that the charged residues D40, R60 and K65 mediate intersubunit electrostatic interactions. Protonation of E79 and E119 is required for structural conversions of the subunits into a dimer conformation, and subsequent protonation of E84 around pH 5.7 leads to the formation of a fully stable dimer. These residues are highly conserved, indicating that the now proposed three-step mechanism prevents premature aggregation of spidroins and enables fast formation of spider silk fibres in general.
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| 33. |
- Landreh, M, et al.
(författare)
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Mass spectrometry captures structural intermediates in protein fiber self-assembly
- 2017
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Ingår i: Chemical communications (Cambridge, England). - : Royal Society of Chemistry (RSC). - 1364-548X .- 1359-7345. ; 53:23, s. 3319-3322
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Tidskriftsartikel (refereegranskat)abstract
- Integrating ion mobility mass spectrometry and molecular dynamics simulations provides insights into intermediates in spider silk formation. The resulting structural models reveal how soluble spidroin proteins use their terminal domains to assemble into silk fibers.
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| 34. |
- Landreh, Michael, et al.
(författare)
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Mass spectrometry captures structural intermediates in protein fiber self-assembly
- 2017
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Ingår i: Chemical Communications. - 1359-7345. ; 53:23, s. 3319-3322
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Tidskriftsartikel (refereegranskat)abstract
- Self-assembling proteins, the basis for a broad range of biological scaffolds, are challenging to study by most structural biology approaches. Here we shown that mass spectrometry (MS) in combination with MD simulations captures structural features of short-lived oligomeric intermediates in spider silk formation, providing direct insights into its complex assembly process.
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| 35. |
- LeBlanc, Gregory, et al.
(författare)
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MAX 4, A 3 GEV light source
- 2003
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Ingår i: Proceedings of the IEEE Particle Accelerator Conference. ; 4, s. 2321-2323
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Konferensbidrag (refereegranskat)abstract
- A proposal for a new synchrotron light source, MAX 4, is presented. The main components are two identical storage rings operated at different electron beam energies and equipped with superconducting insertion devices. Small beam emittances will yield high brilliance radiation over a wide spectral range. A small horizontal emittance is achieved by using a large number of cells with gradient dipoles flanked by horizontally focusing quadrupoles. A small magnet aperture allows strong gradients in dipoles and strong sextupole components in quadrupoles. This results in an equilibrium emittance on the order of 1 nmrad. A full-energy injector, enabling top-up operation, will be a 3 GeV S-band linac with an energy doubling system. This opens up the possibility to produce short, intense radiation pulses, coherent as well as spontaneous.
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| 36. |
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| 37. |
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| 38. |
- Rhomberg, Thomas A., et al.
(författare)
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Proteomic analysis of the sarcosine-insoluble outer membrane fraction of the bacterial pathogen Bartonella henselae
- 2004
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Ingår i: Proteomics. - : Wiley. - 1615-9853 .- 1615-9861. ; 4:10, s. 3021-3033
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Tidskriftsartikel (refereegranskat)abstract
- Bartonella henselae is an emerging zoonotic pathogen causing a wide range of disease manifestations in humans. In this study, we report on the analysis of the sarcosine-insoluble outer membrane fraction of B. henselae ATCC 49882 Houston-1 by one-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis (1-D SDS-PAGE) and two-dimensional nonequilibrium pH gradient polyacrylamide gel electrophoresis (2-D NEPHGE). Protein species were identified by matrix-assisted laser desorption/ionization-time of flight-mass spectrometry (MALDI-TOF-MS) and subsequent database query against the B. henselae genome sequence. Subcellular fractionation, application of the ionic detergent lauryl sarcosine, assessment of trypsin sensitivity, and heat modifiability of surface-exposed proteins represented valuable tools for the analysis of the outer membrane subproteome of B. henselae. 2-D NEPHGE was applied to display and catalogue a substantial number of proteins associated with the B. henselae sarcosine-insoluble outer membrane fraction, resulting in the establishment of a first 2-D reference map of this compartment. Thus, 53 distinct protein species associated with the outer membrane subproteome fraction were identified. This study provides novel insights into the membrane biology and the associated putative virulence factors of this pathogen of increasing medical importance.
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| 39. |
- Rising, Anna, et al.
(författare)
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Artificial Spider Silk for Stem Cell Culture
- 2015
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- There is a great need for defined cell culture systems that allow expansion of human pluripotent stem cells (hPSCs) and subsequent controlled differentiation, ideally in an implantable three-dimensional (3D) matrix. Spider silk appears to be an ideal biomaterial, since it is strong, extendible, and has favorable properties when implanted in living tissues. Spiders are difficult to house and therefor methods for recombinant production of spider silk are warranted. We have developed a method for production of recombinant spider silk fibers, films and foams that are used for the design of defined and xeno-free cell culture matrices. The matrices enable long-term expansion of multiple hPSC lines and subsequent differentiation into all three germ layers in 3D. This hPSC culture method provides robust, defined, easily produced and flexible culture environments for hPSCs (1). These matrices are promising but to realize their full potential, we need to spin continuous fibers in a reproducible way. Spider silk fibers are produced from soluble spidroins under ambient conditions. The spidroins are large and highly repetitive in sequence but capped by non-repetitive N- and C-terminal domains (NT and CT). In the gland, a pH gradient, that goes from 7.6 to <5.7, is generated by active carbonic anhydrase. The terminal domains respond in opposite ways when pH is decreased from 7 to 5: Urea denaturation and temperature stability assays show that NT dimers get significantly stabilized and then lock the spidroins into multimers, while CT on the other hand is destabilized and unfolds into b-sheet amyloid fibrils, which can trigger fiber formation (2,3). There is a high pCO2 in distal parts of the gland, and a CO2 analogue interacts with buried regions in CT as determined by NMR spectroscopy. These simultaneous events constitute a novel CO2 and proton dependent lock and trigger mechanism of spider silk formation that possibly can be harnessed in biomimetic spinning of artificial spider silk. 1. Wu S, Johansson J, Damdimopoulou P, Shahsavani M, Falk A, Hovatta O, Rising A. Spider silk for xeno-free long-term self-renewal and differentiation of human pluripotent stem cells. Biomaterials. 2014 Oct;35(30):8496-502. 2. Kronqvist, N., Otikovs, M., Chmyrov, V., Chen, G., Andersson M., Nordling, K., Landreh, M., Sarr, M., Jörnvall, H, Wennmalm, S., Widengren, J., Meng, Q., Rising, A., Otzen, D., Knight, S. D., Jaudzems, K., Johansson, J. Sequential pH-driven dimerization and stabilization of the N-terminal domain enables rapid spider silk formation Nat Comm. 2014. 10(5):3254. 3. Andersson M, Chen G, Otikovs M, Landreh M, Nordling K, Kronqvist N, Westermark P, Jörnvall H, Knight S, Ridderstråle Y, Holm L, Meng Q, Jaudzems K, Chesler M, Johansson J, Rising A. Carbonic Anhydrase Generates CO2 and H+ That Drive Spider Silk Formation Via Opposite Effects on the Terminal Domains. PLoS Biol. 2014 Aug 5;12(8):e1001921
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| 40. |
- Seltenhammer, Monika H., et al.
(författare)
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Establishment and characterization of a primary and a metastatic melanoma cell line from Grey horses
- 2014
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Ingår i: In vitro Cellular & Developmental Biology-Animal. - : Springer Science and Business Media LLC. - 1071-2690 .- 1543-706X. ; 50:1, s. 56-65
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Tidskriftsartikel (refereegranskat)abstract
- The Grey horse phenotype, caused by a 4.6 kb duplication in Syntaxin 17, is strongly associated with high incidence of melanoma. In contrast to most human melanomas with an early onset of metastasis, the Grey horse melanomas have an extended period of benign growth, after which 50% or more eventually undergo progression and may metastasize. In efforts to define changes occurring during Grey horse melanoma progression, we established an in vitro model comprised of two cell lines, HoMel-L1 and HoMel-A1, representing a primary and a metastatic stage of the melanoma, respectively. The cell lines were examined for their growth and morphological characteristics, in vitro and in vivo oncogenic potential, chromosome numbers, and expression of melanocytic antigens and tumor suppressors. Both cell lines exhibited malignant characteristics; however, the metastatic HoMel-A1 showed a more aggressive phenotype characterized by higher proliferation rates, invasiveness, and a stronger tumorigenic potential both in vitro and in vivo. HoMel-A1 displayed a near-haploid karyotype, whereas HoMel-L1 was near-diploid. The cell lines expressed melanocytic lineage markers such as TYR, TRP1, MITF, PMEL, ASIP, MC1R, POMC, and KIT. The tumor suppressor p53 was strongly expressed in both cell lines, while the tumor suppressors p16 and PTEN were absent in HoMel-A1, potentially implicating significance of these pathways in the melanoma progression. This in vitro model system will not only aid in understanding of the Grey horse melanoma pathogenesis, but also in unraveling the steps during melanoma progression in general as well as being an invaluable tool for development of new therapeutic strategies.
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| 41. |
- Ågerstrand, Marlene, et al.
(författare)
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A call for action : Improve reporting of research studies to increase the scientific basis for regulatory decision-making
- 2018
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Ingår i: Journal of Applied Toxicology. - : Wiley. - 0260-437X .- 1099-1263. ; 38:5, s. 783-785
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Tidskriftsartikel (refereegranskat)abstract
- This is a call for action to scientific journals to introduce reporting requirements for toxicity and ecotoxicity studies. Such reporting requirements will support the use of peer-reviewed research studies in regulatory decision-making. Moreover, this could improve the reliability and reproducibility of published studies in general and make better use of the resources spent in research.
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