| 1. |
- Andersson Chronholm, Jannika, 1972-, et al.
(författare)
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Förstaårsstudenters och lärares förhållningssätt till laborationer i fysik
- 2014
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Konferensbidrag (refereegranskat)abstract
- Laborationer används som ett närmast självklart inslag på naturvetenskapliga utbildningar. Mål och syften med laborationer kan skifta mellan olika kurser och är inte alltid uppenbara för studenterna (Hart et al., 2000; Russell & Weaver, 2008). Ofta förväntas de lära sig hantering av utrustning, tolkning av data och rapportskrivning, samtidigt som de ska få bättre förståelse för teorin genom att seJohan Larsson undersökte 2012 hur hans studenter på tekniskt-naturvetenskapligt basår (högskoleförberedande) värderade olika undervisningsformer. Laborationer fick då sämst betyg. För att undersöka möjliga orsaker till detta tog vi initiativ till en fenomenografisk studie (Marton, 1981) av attityder till fysiklaborationer. Skriftliga enkätsvar samlades in från 38 förstaårsstudenter på kandidatprogrammet i fysik vid Uppsala universitet. Den öppna enkätfrågan inspirerades av en amerikansk studiebesvarades även av 18 anonyma lärare på Institutionen för fysik och astronomi. Både lärare och studenter har skrivit långa svar som vi kategoriserat fenomenografiskt, det vill säga vi har kartlagt förekomsten av attityder.Det finns tydliga nivåer av progression; från ett distanserat, ointresserat förhållningssätt till en nivå där man har en uppfattning om framtida behov. Studien visar inte på några större skillnader mellan lärarnas och studenternas syn. Laborationer förväntas koppla teori till praktik samt ge tillfälle att träna på instrumenthantering och vetenskapligt arbetssätt. Några nämner också att laborationer ökar deras förståelse och lärande, ger social träning och förbereder dem för ett kommande arbetsliv.Vår avsikt är att använda resultaten för att öka laborationernas upplevda värde, genom att uppmärksamma kollegor på de förekommande förhållningssätten och tillsammans förbereda oss för att bemöta dem. Frågor som vi vill diskutera är t.ex.: Vill vi att studenterna ska tycka så här?Hur speglar våra laborationsinstruktioner det vi vill att studenterna ska lära sig? Hur kommunicerar vi mål och syften med varje laboration på bästa sätt?Hart C., Mulhall, P., Berry, A., Loughran, J., & Gunstone, R. (2000). What is the purpose of this experiment? Or can students learn something from doing experiments? Journal of Research in Science Teaching, 37(7), 655-675. Marton, F. (1981). Phenomenography Describing conceptions of the world around us. Instructional Science, 10, 177-200.Russell, C. B., & Weaver, G. C. (2008). Student Perceptions of the Purpose and Function of the Laboratory in Science: A Grounded Theory Study. International Journal for the Scholarship of Teaching and Learning, 2(2), 1-14.
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| 2. |
- Andersson Chronholm, Jannika, 1972-, et al.
(författare)
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Förstaårsstudenters och lärares syn på laborationer i fysik
- 2013
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Konferensbidrag (refereegranskat)abstract
- BakgrundDå institutionen för fysik och astronomi under 2013 identifierat laborationerna som ett problemområde har vi gjort en fenomenografisk studie som undersökte studenters och lärares syn på laborationer. Datainsamling och analysVi har samlat in skriftliga enkätsvar från 18 lärare och 38 förstaårsstudenter på kandidatprogrammet i fysik.Den öppna enkätfrågan var : - Varför har vissa kurser laborationer?Svaren visar på många olika uppfattningar och vi har kategoriserat dessa fenomenografiskt. ResultatVi ser tydliga nivåer av progression i svaren; från ett distanserat och ointresserat förhållningssätt, till en uppfattning om lärande och framtida yrkesliv.Studien visar att lärare och studenterna har mycket lika syn på laborationer.Uppfattningar som fördes fram var att kurser har laborationer för att : l det är obligatorisktl koppla teori till praktikl öva instrumenthanteringl träna vetenskapligt arbetssättl öka förståelsen och lärandetl ge social träningl utgöra förberedelse för arbetsliv ReferenserMarton, F. (1981) Phenomenography – Describing conceptions of the world around us. Instructional Science, 10, 177-200.Russell, C. B. and Weaver, G. C. (2008) Student Perceptions of the Purpose and Function of the Laboratory in Science: A Grounded Theory Study. International Journal for the Scholarship of Teaching and Learning 2(2).
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| 3. |
- Andersson, Gabriella, et al.
(författare)
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Aktiverande problemlösningsövningar i grupp.
- 2010
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Ingår i: Att undervisa med vetenskaplig förankring – i praktiken!. - Uppsala : Universitetstryckeriet. ; , s. 103-113
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 4. |
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| 5. |
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| 6. |
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| 7. |
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| 8. |
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| 9. |
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| 10. |
- Andersson, Lisa, et al.
(författare)
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Mutations in DMRT3 affect locomotion in horses and spinal circuit function in mice
- 2012
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 488:7413, s. 642-646
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Tidskriftsartikel (refereegranskat)abstract
- Locomotion in mammals relies on a central pattern-generating circuitry of spinal interneurons established during development that coordinates limb movement(1). These networks produce left-right alternation of limbs as well as coordinated activation of flexor and extensor muscles(2). Here we show that a premature stop codon in the DMRT3 gene has a major effect on the pattern of locomotion in horses. The mutation is permissive for the ability to perform alternate gaits and has a favourable effect on harness racing performance. Examination of wild-type and Dmrt3-null mice demonstrates that Dmrt3 is expressed in the dI6 subdivision of spinal cord neurons, takes part in neuronal specification within this subdivision, and is critical for the normal development of a coordinated locomotor network controlling limb movements. Our discovery positions Dmrt3 in a pivotal role for configuring the spinal circuits controlling stride in vertebrates. The DMRT3 mutation has had a major effect on the diversification of the domestic horse, as the altered gait characteristics of a number of breeds apparently require this mutation.
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| 11. |
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| 12. |
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| 13. |
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| 14. |
- Jäderkvist Fegraeus, Kim, et al.
(författare)
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The DMRT3 'Gait keeper' mutation affects performance of Nordic and Standardbred trotters
- 2014
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Ingår i: Journal of Animal Science. - : Oxford University Press (OUP). - 0021-8812 .- 1525-3163. ; 92:10, s. 4279-4286
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Tidskriftsartikel (refereegranskat)abstract
- In a previous study it was shown that a nonsense mutation in the DMRT3 gene alters the pattern of locomotion in horses and that this mutation has a strong positive impact on trotting performance of Standardbreds. One aim of this study was to test if racing performance and trotting technique in the Nordic (Coldblood) trotters are also influenced by the DMRT3 genotype. Another aim was to further investigate the effect of the mutation on performance in Standardbreds, by using a within-family analysis and genotype-phenotype correlations in a larger horse material than in the previous study. We genotyped 427 Nordic trotters and 621 Standardbreds for the DMRT3 nonsense mutation and a SNP in strong linkage disequilibrium with it. In Nordic trotters, we show that horses homozygous for the DMRT3 mutation (A) had significantly higher EBV for trotting performance traits than heterozygous (CA) or homozygous wild-type (CC) horses (P = 0.001). Furthermore, AA homozygotes had a higher proportion of victories and top 3 placings than horses heterozygous or homozygous wild-type, when analyzing performance data for the period 3 to 6 yr of age (P = 0.06 and P = 0.05, respectively). Another finding in the Nordic trotters was that the DMRT3 mutation influenced trotting technique (P = 2.1 x 10(-8)). Standardbred horses homozygous AA had significantly higher EBV for all traits than horses with at least 1 wild-type allele (CA and CC; P = 1.6 x 10(-16)). In a within-family analysis of Standardbreds, we found significant differences in several traits (e. g., earnings, P = 0.002; number of entered races, P = 0.004; and fraction of offspring that entered races, P = 0.002) among paternal half-sibs with genotype AA or CA sired by a CA stallion. For most traits, we found significant differences at young ages. For Nordic trotters, most of the results were significant at 3 yr of age but not for the older ages, and for the Standardbreds most of the results for the ages 3 to 5 were significant. For Nordic trotters, the proportion of victories and placings were the only traits that were significant for other ages than 3 yr.
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| 15. |
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| 16. |
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| 17. |
- Lindgren, Gabriella, et al.
(författare)
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Travtalang ligger i hästens gener
- 2013
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Ingår i: Travtränaren. ; , s. 1-6
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- I denna artikel, som är nummer ett i en serie om två, fokuserar vi på resultaten från varm- och kallblodstravare. Vi resonerar kring när och för vem ett DNA-test är till mest nytta samt beskriver hur man praktiskt går tillväga. I artikel nummer två kommer vi berätta om hur forskningen gick till, vad genen gör i hästens kropp och resultatet från andra raser. Vi kommer även gå djupare in på vad DNA är och vad vi troligen kan förvänta oss av DNA-teknik i framtiden.
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| 18. |
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| 19. |
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| 20. |
- Promerová, Marta, et al.
(författare)
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Worldwide frequency distribution of the 'Gait keeper' mutation in the DMRT3 gene
- 2014
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Ingår i: Animal Genetics. - : Wiley. - 0268-9146 .- 1365-2052. ; 45:2, s. 274-282
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Tidskriftsartikel (refereegranskat)abstract
- For centuries, domestic horses have represented an important means of transport and served as working and companion animals. Although their role in transportation is less important today, many horse breeds are still subject to intense selection based on their pattern of locomotion. A striking example of such a selected trait is the ability of a horse to perform additional gaits other than the common walk, trot and gallop. Those could be four-beat ambling gaits, which are particularly smooth and comfortable for the rider, or pace, used mainly in racing. Gaited horse breeds occur around the globe, suggesting that gaitedness is an old trait, selected for in many breeds. A recent study discovered that a nonsense mutation in DMRT3 has a major impact on gaitedness in horses and is present at a high frequency in gaited breeds and in horses bred for harness racing. Here, we report a study of the worldwide distribution of this mutation. We genotyped 4396 horses representing 141 horse breeds for the DMRT3 stop mutation. More than half (2749) of these horses also were genotyped for a SNP situated 32kb upstream of the DMRT3 nonsense mutation because these two SNPs are in very strong linkage disequilibrium. We show that the DMRT3 mutation is present in 68 of the 141 genotyped horse breeds at a frequency ranging from 1% to 100%. We also show that the mutation is not limited to a geographical area, but is found worldwide. The breeds with a high frequency of the stop mutation (>50%) are either classified as gaited or bred for harness racing.
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| 21. |
- Ahlberg, Martina, 1980-
(författare)
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Critical Phenomena and Exchange Coupling in Magnetic Heterostructures
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The continuous phase transition in thin magnetic films and superlattices has been studied using the magneto-optical Kerr effect (MOKE) and polarized neutron scattering (PNR). It has been shown that the critical behavior of amorphous thin films belonging to the 2D XY universality class can be described within the same theory as crystalline sample. This means that quenched disorder only serves as a marginal perturbation in systems with this symmetry. The connection between interlayer exchange coupling and the observed critical behavior in Fe/V superlattices was explored. The results prove that the origin of unusually high values of the exponent β can be traced to a position dependence of the magnetization at elevated temperatures. The magnetization of the outermost layers within the superlattice shows a more pronounced decrease at lower temperatures, compared to the inner layers, which in turn have a more abrupt decrease in the vicinity of the critical temperature. This translates to a high exponent, especially when the layers are probed by a technique where more weight is given to the layers close to the surface, e.g.MOKE. The interlayer exchange coupling as a function of spacer thickness and temperature was also studied in its own right. The data was compared to the literature, and a dependence on the thickness of the magnetic layers was concluded. The phase transition in amorphous FeZr/CoZr multilayers, where the magnetization emanates from ferromagnetic proximity effects, was investigated. Even though the determined exponents of the zero-field magnetization, the susceptibility and the critical isotherm did not correspond to any universality class, scaling plots displayed an excellent data collapse. Samples consisting of Fe δ-layers (0.3-1.4 monolayers) embedded in Pd were studied using element-specific resonant x-ray magnetic scattering. The magnetization of the two constituents showed distinctly different temperature dependences.
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| 22. |
- Ahlberg, Martina, et al.
(författare)
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Effect of ferromagnetic proximity on critical behavior
- 2012
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Ingår i: Physical Review B Condensed Matter. - 0163-1829 .- 1095-3795. ; 85:22, s. 224425-1-224425-6
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Tidskriftsartikel (refereegranskat)abstract
- We have investigated the magnetic phase transition in amorphous Fe93Zr7(x angstrom)/Co95Zr5(1 angstrom) multilayers, where x = 25, 50, and 75. The extremely thin CoZr layer induces magnetic order at temperatures well above the inherent ordering temperature of Fe93Zr7. The changes in the critical exponent beta, associated with the temperature dependence of the magnetization, imply a crossover from two-to three-dimensional behavior as the FeZr thickness is reduced, consistent with a substantial magnetic induction in the FeZr layers. In addition we determined the exponents delta and gamma, of the critical isotherm and the susceptibility, respectively, and their values confirm the nonuniversal character of the phase transition. Scaling of the results yields an excellent data collapse and is found to hold in the crossover regime where the universality hypothesis is not applicable.
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| 23. |
- Ahlberg, Martina, et al.
(författare)
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Influence of boundaries on magnetic ordering in Fe/V superlattices
- 2010
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 81:21, s. 214429-
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Tidskriftsartikel (refereegranskat)abstract
- We study the role of surface boundaries on the magnetic properties of [Fe/V](n) superlattice structures, with n=2-10. Using the magneto-optical Kerr effect and polarized neutron reflectivity measurements, we examine the evolution of both the total and the layer-resolved magnetizations as a function of temperature. By varying n, we observe a large shift in the transition temperatures T-c and a substantial change in the total magnetization critical exponent beta. In particular, the thicker samples exhibit nonuniversal exponent values. By resolving the magnetization as a function of position within the superlattice, we show that this behavior arises from contributions of the surfaces. Furthermore, we attribute the large shift in T-c to long-ranged interactions present in the superlattice.
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| 24. |
- Ahlberg, Martina, et al.
(författare)
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Two-dimensional XY-like amorphous Co68Fe24Zr8/Al70Zr30 multilayers
- 2011
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 83:22, s. 224404-
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Tidskriftsartikel (refereegranskat)abstract
- We present an experimental realization of a magnetic two-dimensional XY system using amorphous materials. The classification of the dimensionality is based on the critical behavior of amorphous Co68Fe24Zr8(d)/Al70O30 (20 angstrom) multilayers, where d = 11 - 16 angstrom. Analysis of the remanent magnetization, the magnetic isotherms, the initial susceptibility, and the magnetic correlation length shows that the magnetic phase transition can be described by the 2D XY model. The samples are not paramagnetic above the critical temperature but are characterized by local magnetic order manifested in the field and temperature dependence of the magnetization. Furthermore, an average spin-spin interaction length of 8.1 angstrom was estimated using the thickness dependence of the Curie temperature.
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| 25. |
- Andersson, Gabriella, et al.
(författare)
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Anisotropy Tuning in Tetragonal FeCo Alloys
- 2010
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Ingår i: Journal of Nanoscience and Nanotechnology. - : American Scientific Publishers. - 1533-4880 .- 1533-4899. ; 10:9, s. 6186-6189
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Tidskriftsartikel (refereegranskat)abstract
- We review our previous work on magnetocrystalline anisotropy tuning of superlattices based on tetragonally distorted FeCo-alloys. In addition we present new experimental results on the effect of changing the composition of the FeCo alloy. The discussion is based on the separation of the magnetocrystalline anisotropy into contributions from the interfaces and strain, as well as from the composition.
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| 26. |
- Andersson, Gabriella, 1972-
(författare)
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Rätt klack - och rätt sula
- 2013
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Ingår i: Skor är huvudsaken. - : Uppsala universitet. - 9789150623345 ; , s. 32-34
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Bokkapitel (populärvet., debatt m.m.)
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| 27. |
- Andersson, Lisa, et al.
(författare)
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Augendefekte bei windfarbenen Pferden
- 2012
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Ingår i: Eiðfaxi, Islandpferdemagazin. - 1023-3350. ; , s. 70-75
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Tidskriftsartikel (populärvet., debatt m.m.)
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| 28. |
- Andersson, Lisa, et al.
(författare)
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Augngallar í vindóttum hrossum
- 2012
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Ingår i: Eiðfaxi, Icelandic horse Magazine. - 1023-3342. ; , s. 42-47
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Tidskriftsartikel (populärvet., debatt m.m.)
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| 29. |
- Andersson, Lisa, et al.
(författare)
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Equine multiple congenital ocular anomalies and silver coat colour result from the pleiotropic effects of mutant PMEL
- 2013
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Equine Multiple Congenital Ocular Anomalies (MCOA) syndrome is a heritable eye disorder mainly affecting silver colored horses. Clinically, the disease manifests in two distinct classes depending on the horse genotype. Horses homozygous for the mutant allele present with a wide range of ocular defects, such as iris stromal hypoplasia, abnormal pectinate ligaments, megaloglobus, iridociliary cysts and cataracts. The phenotype of heterozygous horses is less severe and predominantly includes iridociliary cysts, which occasionally extend into the temporal retina. In order to determine the genetic cause of MCOA syndrome we sequenced the entire previously characterized 208 kilobase region on chromosome 6 in ten individuals; five MCOA affected horses from three different breeds, one horse with the intermediate Cyst phenotype and four unaffected controls from two different breeds. This was performed using Illumina TruSeq technology with paired-end reads. Through the systematic exclusion of all polymorphisms barring two SNPs in PMEL, a missense mutation previously reported to be associated with the silver coat colour and a non-conserved intronic SNP, we establish that this gene is responsible for MCOA syndrome. Our finding, together with recent advances that show aberrant protein function due to the coding mutation, suggests that the missense mutation is causative and has pleiotrophic effect, causing both the horse silver coat color and MCOA syndrome.
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| 30. |
- Andersson, Lisa, et al.
(författare)
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Genetic diversity in the modern horse illustrated from genome-wide SNP data
- 2013
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 8
-
Tidskriftsartikel (refereegranskat)abstract
- Horses were domesticated from the Eurasian steppes 5,000-6,000 years ago. Since then, the use of horses for transportation, warfare, and agriculture, as well as selection for desired traits and fitness, has resulted in diverse populations distributed across the world, many of which have become or are in the process of becoming formally organized into closed, breeding populations (breeds). This report describes the use of a genome-wide set of autosomal SNPs and 814 horses from 36 breeds to provide the first detailed description of equine breed diversity. FST calculations, parsimony, and distance analysis demonstrated relationships among the breeds that largely reflect geographic origins and known breed histories. Low levels of population divergence were observed between breeds that are relatively early on in the process of breed development, and between those with high levels of within-breed diversity, whether due to large population size, ongoing outcrossing, or large within-breed phenotypic diversity. Populations with low within-breed diversity included those which have experienced population bottlenecks, have been under intense selective pressure, or are closed populations with long breed histories. These results provide new insights into the relationships among and the diversity within breeds of horses. In addition these results will facilitate future genome-wide association studies and investigations into genomic targets of selection.
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| 31. |
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| 32. |
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| 33. |
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| 34. |
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| 35. |
- Andersson, Lisa, et al.
(författare)
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Targeted analysis of four breeds narrows equine Multiple Congenital Ocular Anomalies locus to 208 kilobases
- 2011
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Ingår i: Mammalian Genome. - : Springer Science and Business Media LLC. - 0938-8990 .- 1432-1777. ; 22, s. 353-360
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Tidskriftsartikel (refereegranskat)abstract
- The syndrome Multiple Congenital Ocular Anomalies (MCOA) is the collective name ascribed to heritable congenital eye defects in horses. Individuals homozygous for the disease allele (MCOA phenotype) have a wide range of eye anomalies, while heterozygous horses (Cyst phenotype) predominantly have cysts that originate from the temporal ciliary body, iris, and/or peripheral retina. MCOA syndrome is highly prevalent in the Rocky Mountain Horse but the disease is not limited to this breed. Affected horses most often have a Silver coat color; however, a pleiotropic link between these phenotypes is yet to be proven. Locating and possibly isolating these traits would provide invaluable knowledge to scientists and breeders. This would favor maintenance of a desirable coat color while addressing the health concerns of the affected breeds, and would also provide insight into the genetic basis of the disease. Identical-by-descent mapping was used to narrow the previous 4.6-Mb region to a 264-kb interval for the MCOA locus. One haplotype common to four breeds showed complete association to the disease (Cyst phenotype, = 246; MCOA phenotype, n = 83). Candidate genes from the interval, SMARCC2 and IKZF4, were screened for polymorphisms and genotyped, and segregation analysis allowed the MCOA syndrome region to be shortened to 208 kb. This interval also harbors PMEL17, the gene causative for Silver coat color. However, by shortening the MCOA locus by a factor of 20, 176 other genes have been unlinked from the disease and only 15 genes remain.
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| 36. |
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| 37. |
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| 38. |
- Andersson, Lisa, et al.
(författare)
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The same ELA class II risk factors confer equine insect bite hypersensitivity in two distinct populations
- 2012
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Ingår i: Immunogenetics. - : Springer Science and Business Media LLC. - 0093-7711 .- 1432-1211. ; 64:3, s. 201-208
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Tidskriftsartikel (refereegranskat)abstract
- Insect bite hypersensitivity (IBH) is a chronic allergic dermatitis common in horses. Affected horses mainly react against antigens present in the saliva from the biting midges, Culicoides ssp, and occasionally black flies, Simulium ssp. Because of this insect dependency, the disease is clearly seasonal and prevalence varies between geographical locations. For two distinct horse breeds, we genotyped four microsatellite markers positioned within the MHC class II region and sequenced the highly polymorphic exons two from DRA and DRB3, respectively. Initially, 94 IBH-affected and 93 unaffected Swedish born Icelandic horses were tested for genetic association. These horses had previously been genotyped on the Illumina Equine SNP50 BeadChip, which made it possible to ensure that our study did not suffer from the effects of stratification. The second population consisted of 106 unaffected and 80 IBH-affected Exmoor ponies. We show that variants in the MHC class II region are associated with disease susceptibility (p(raw)=2.34x10(-5)), with the same allele (COR112:274) associated in two separate populations. In addition, we combined microsatellite and sequencing data in order to investigate the pattern of homozygosity and show that homozygosity across the entire MHC class II region is associated with a higher risk of developing IBH (p=0.0013). To our knowledge this is the first time in any atopic dermatitis suffering species, including man, where the same risk allele has been identified in two distinct populations.
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| 39. |
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| 40. |
- Arnalds, Unnar B., et al.
(författare)
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Magnetic structure and diffracted magneto-optics of patterned amorphous multilayers
- 2010
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 82:14, s. 144434-1-144434-8
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Tidskriftsartikel (refereegranskat)abstract
- We present magneto-optical Kerr effect measurements of patterned arrays of Co68Fe24Zr8 / Al2O3 amorphous multilayers. The multilayers were patterned in two dimensions into two different arrangements of circular and ellipsoidal islands. Magnetization loops were recorded in a longitudinal geometry using both the specularly reflected beam as well as diffracted beams scattered off the patterned films. The magnetization of the patterned structures is significantly different from the magnetization of a continuous multilayer owing to the lateral confinement of the pattern and the introduction of additional dipolar coupling between the layers at the edges of the islands. By investigating the magnetic response at the different diffraction orders from the two different configurations of islands we are able to observe the magnetization at different length scales and determine the magnetic response of the circular and ellipsoidal islands individually.
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| 41. |
- Björnsdóttir, Sigridur, et al.
(författare)
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The effect of the ‘Gait keeper’ mutation in the DMRT3 gene on gaiting ability in Icelandic horses
- 2014
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Ingår i: Journal of Animal Breeding and Genetics. - : Wiley. - 0931-2668 .- 1439-0388. ; 131, s. 415-425
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Tidskriftsartikel (refereegranskat)abstract
- A nonsense mutation in DMRT3 (‘Gait keeper' mutation) has a predominant effect on gaiting ability in horses, being permissive for the ability to perform lateral gaits and having a favourable effect on speed capacity in trot. The DMRT3 mutant allele (A) has been found in high frequency in gaited breeds and breeds bred for harness racing, while other horse breeds were homozygous for the wild-type allele (C). The aim of this study was to evaluate further the effect of the DMRT3 nonsense mutation on the gait quality and speed capacity in the multigaited Icelandic horse and demonstrate how the frequencies of the A- and C- alleles have changed in the Icelandic horse population in recent decades. It was confirmed that homozygosity for the DMRT3 nonsense mutation relates to the ability to pace. It further had a favourable effect on scores in breeding field tests for the lateral gait t€olt, demonstrated by better beat quality, speed capacity and suppleness. Horses with the CA genotype had on the other hand significantly higher scores for walk, trot, canter and gallop, and they performed better beat and suspension in trot and gallop. These results indicate that the AA genotype reinforces the coordination of ipsilateral legs, with the subsequent negative effect on the synchronized movement of diagonal legs compared with the CA genotype. The frequency of the A-allele has increased in recent decades with a corresponding decrease in the frequency of the C-allele. The estimated frequency of the A-allele in the Icelandic horse population in 2012 was 0.94. Selective breeding for lateral gaits in the Icelandic horse population has apparently altered the frequency of DMRT3 genotypes with a predicted loss of the C-allele in relatively few years. The results have practical implications for breeding and training of Icelandic horses and other gaited horse breeds.
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| 42. |
- Bran, Cristina, et al.
(författare)
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Magnetic Properties of Fe/WRe (001) Multilayers
- 2014
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Ingår i: Journal of Surfaces and Interfaces of Materials. - : American Scientific Publishers. - 2164-7542. ; 2:1, s. 33-39
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Tidskriftsartikel (refereegranskat)abstract
- Following recent theoretical predictions on perpendicular uniaxial magnetocrystalline anisotropy in multilayers of 5 monolayers of Fe and 2 monolayers of W x Re100–x with tetragonally strained components, we have measured the magnetization and detailed atomic structure in a series of such samples with x = 20–80 at%. Although the achieved strain in the WRe layers is smaller than in the modelled case, we do observe a positive uniaxial magnetocrystalline anisotropy of around 0.6 MJ/m3 at 40 K, after accounting for the in-plane shape anisotropy. This causes the out-of-plane saturation field to be reduced considerably compared to a pure Fe thin film, while the saturation magnetization is maintained at a value which is enhanced by at least 30% from what would be expected from the multilayer composition alone. The coercivity is low, on the order of 6 kA/m in all samples.
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| 43. |
- Brolen, Gabriella, et al.
(författare)
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Hepatocyte-like cells derived from human embryonic stem cells specifically via definitive endoderm and a progenitor stage
- 2010
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Ingår i: Journal of Biotechnology. - : Elsevier BV. - 1873-4863 .- 0168-1656. ; 145:3, s. 284-294
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Tidskriftsartikel (refereegranskat)abstract
- Human embryonic stem cells offer a potential unlimited supply for functional hepatocytes, since they can differentiate into hepatocyte-like cells displaying a characteristic hepatic morphology and expressing various hepatic markers. These cells could be used in various applications such as studies of drug metabolism and hepatotoxicity, which however, would require a significant expression of drug metabolizing enzymes. To derive these cells we use a stepwise differentiation protocol where growth- and maturation factors are added. The first phase involves the formation of definitive endoderm. Next, these cells are treated with factors known to promote the induction and proliferation towards hepatic progenitor cell types. In the last phase the cells are terminally differentiated and maturated into functional hepatocyte-like cells. The cultures were characterized by analysis of endodermal or hepatic markers and compared to cultures derived without induction via definitive endoderm. Hepatic functions such as urea secretion, glycogen storage, indocyanine green uptake and secretion, and cytochrome P450-expression and activity were evaluated. The DE-Hep showed a hepatocyte morphology with sub-organized cells and exhibited many liver-functions including transporter activity and capacity to metabolize drugs specific for important cytochrome P450 sub-families. This represents an importantstep in differentiation of hESC into functional hepatocytes. (C) 2009 Elsevier B.V. All rights reserved.
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| 44. |
- Jäderkvist Fegraeus, Kim, et al.
(författare)
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Gaitedness is associated with the DMRT3 'Gait keeper' mutation in Morgan and American Curly horses
- 2014
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Ingår i: Animal Genetics. - : Wiley. - 0268-9146 .- 1365-2052. ; 45, s. 908-909
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Annan publikation (refereegranskat)abstract
- The nonsense mutation in the DMRT3 gene is known to affect locomotion pattern and gait ability in horses[1] and performance of Standardbred and Nordic trotters.[1, 2] The mutation (a change from cytosine, C, to adenine, A) has been found in all tested gaited breeds and in breeds used for harness racing, whereas it is absent in most of the three-gaited breeds, such as the Swedish Warmblood and Thoroughbreds.[3] Previous studies have shown that the mutation is strongly associated with horses' ability to perform alternate gaits.[1, 3, 4] In the study by Promerová etal.,[3] breeds with a frequency of the mutation at 50% or higher were classified as either gaited or breeds used for harness racing. There are many different types of alternate gaits, for example foxtrot, running walk, tölt and pace.[3] In this study, we investigated if there is a connection between the genotype in DMRT3 and gaitedness in Morgan and American Curly horses. Previous study showed that the frequency of the mutated A allele in these breeds was 14.0% and 16.7% respectively.[3]
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| 45. |
- Korelis, Panagiotis, 1984-
(författare)
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Uncovering Magnetic Order in Nanostructured Disordered Materials : A Study of Amorphous Magnetic Layered Structures
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The scope of this thesis is the study of the interplay between structure and magnetism in amorphous materials. The investigations focus on the growth of amorphous layers and the study of the influence of structural disorder and reduced physical extension on the magnetic properties of thin films and multilayers. The examined magnetic materials are FeZr alloys, as well as other amorphous transition metal alloys such as CoZr and FeCoZr. Thin films and multilayers of the studied materials were deposited using magnetron sputtering in ultra-high vacuum conditions. Their amorphous structure and layering quality was investigated using X-ray scattering techniques and in several cases with transmission electron microscopy. The chemical composition of the alloys was determined with Rutherford Backscattering Spectrometry. The magnetic properties were investigated using the magneto-optic Kerr effect and SQUID magnetometry, as well as polarized neutron reflectometry and X-ray magnetic circular dicroism measurements. For FeZr alloys deposited as multilayers with Al2O3 as spacer layer, it was found that Fe-rich nanocrystallites, formed at the metal/oxide interfaces, exert large influence on the magnetic properties. The use of AlZr alloys as buffer layers promotes the growth of highly amorphous FeZr layers. FeZr/AlZr multilayers with good layering quality can also be obtained. The influence of the reduced layer thickness on the magnetic moment, Curie temperature and magnetic dimensionality of the magnetic layers is addressed for FeZr/AlZr multilayers. Thin FeZr layers in these structures are found to belong to the 2D XY dimensionality class. The change of the magnetic moment and Curie temperature with reduced FeZr layer thickness is quantified. In addition, the induced magnetic moment in the alloy element Zr was investigated in FeZr and CoZr alloy films. The possibility to imprint a preferred magnetization direction during thin film preparation was demonstrated for FeCoZr layers. Lastly, AlZr alloy films were studied with respect to their oxidation stability at room and elevated temperatures, aiming towards development of materials with passivating properties.
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| 46. |
- Kumar Puri, Anil, et al.
(författare)
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Reentrant Superspin Glass Phase in a La0.82Ca0.18MnO3 Ferromagnetic Insulator
- 2014
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Ingår i: Physical Review X. - 2160-3308. ; 4:1, s. 011037-
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Tidskriftsartikel (refereegranskat)abstract
- We report results of the magnetization and ac susceptibility measurements down to very low fields on a single crystal of the perovskite manganite, La-0.82 Ca-0.18 MnO3. This composition falls in the intriguing ferromagnetic insulator region of the manganite phase diagram. In contrast to earlier beliefs, our investigations reveal that magnetically (and in every other sense), this is a single- phase system with a ferromagnetic ordering temperature of around 170 K. However, this ferromagnetic state is magnetically frustrated, and the system exhibits pronounced glassy dynamics below 90 K. Based on measured dynamical properties, we propose that this quasi-long-ranged ferromagnetic phase, and the associated superspin glass behavior, is the true magnetic state of the system, rather than being a macroscopic mixture of ferromagnetic and antiferromagnetic phases, as often suggested. Our results provide an understanding of the quantum phase transition from an antiferromagnetic insulator to a ferromagnetic metal via this ferromagnetic state as a function of x in La1-xCaxMnO3, in terms of the possible formation of magnetic polarons.
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| 47. |
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| 48. |
- Lillsunde-Larsson, Gabriella, 1971-, et al.
(författare)
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Human Papillomavirus (HPV) and HPV 16-Variant Distribution in Vulvar Squamous Cell Carcinoma in Sweden
- 2012
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Ingår i: International Journal of Gynecological Cancer. - 1048-891X .- 1525-1438. ; 22:8, s. 1413-1419
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To investigate the human papillomavirus (HPV) and HPV type 16-variant distribution in a series of vulvar squamous cell carcinomas (VSCC) and to evaluate the impact of HPV and HPV 16-variant on prognosis.Methods: A series of 133 patients who had a diagnosis of VSCC (1983-2008) was selected for the study. Detection of 11 high-risk HPV types (16, 18, 31, 33, 39, 45, 51, 52, 56, 58, and 59) and 2 low-risk HPV types (6 and 11) was performed with real-time polymerase chain reaction. Samples positive for HPV 16 were further analyzed for variant determination of 7 positions in the E6 gene with polymerase chain reaction and pyrosequencing.Results: Forty (30.8%) of 130 tumors were found to be HPV positive. Human papillomavirus type 16 was found in 31 cases, HPV 18 was found in 2 cases, HPV 33 was found in 5 cases, and HPV 56 and HPV 59 were found in one case each. All but one tumor harboring HPV 16 were of European linage, and the 3 most common variants were E-p (n = 13), E-G350 (n = 7), and E-G131 (n = 5). HPV positivity was associated with the basaloid tumor type and occurred in significantly younger patients. Overall and recurrence-free survival rates were better in HPV-positive cases, but after correction for age and tumor size, HPV status was no longer an independent and significant prognostic factor. The survival rates of the various HPV 16 variants were not significantly different, but there was a trend of worse outcome for the E-G131-variant group.Conclusions: Human papillomavirus positivity of 30.8% is similar to other reports on VSCC. To our knowledge, this first variant determination of HPV 16 in vulvar carcinoma in a Swedish cohort indicated that the variant E-G131 may have an increased oncogenic potential in patients with VSCC.
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| 49. |
- Lillsunde-Larsson, Gabriella, 1971-, et al.
(författare)
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Prognostic impact of human papilloma virus (HPV) genotyping and HPV-16 subtyping in vaginal carcinoma
- 2013
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Ingår i: Gynecologic Oncology. - : Elsevier BV. - 0090-8258 .- 1095-6859. ; 129:2, s. 406-411
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Tidskriftsartikel (refereegranskat)abstract
- ObjectiveThe objectives of this study are to investigate the human papilloma virus (HPV) distribution in vaginal cancer and to evaluate HPV-genotype as well as HPV16-variant impact on prognosis.MethodsSixty-nine patients diagnosed with primary vaginal carcinoma (1975-2002) were included in the study. Detection of twelve high-risk HPV (hr HPV) and two low-risk HPV (lr HPV) was performed with realtime-PCR. Samples positive for HPV-16 were analyzed for variants in the E6-gene with PCR and pyrosequencing.Results53.6% (37/69) of the tumors were found to be HPV-positive, mostly for HPV-16 (N=26). Other HPV-types were HPV-18 (N=2), HPV-31 (N=2), HPV-33 (N=2), HPV-45 (N=1), HPV-52 (N=2), HPV-56 (N=1) and HPV-58 (N=1). Only European subtypes of HPV-16 were represented and the two most common HPV-16-variants were E-p (N=13) and E-G350 (N=11). Patients with HPV-positive tumors (N=37) had a significantly (log-rank test=3341; p = 0.0008) superior 5-year overall survival rate as well as cancer-specific survival rate and progression-free survival rate (p = 0.0002; p = 0.0004), compared with patients with HPV-negative tumors (N=32). Interestingly, patients with HPV-16-positive tumors had a superior overall survival compared with patients with tumors containing other HPV-genotypes. In a Cox proportional multivariate analysis age, tumor size, and HPV-status were independent and significant prognostic factors with regard to overall survival rate.ConclusionsHPV-status is of prognostic importance in vaginal carcinoma and varies with viral genotype. In this era of HPV-vaccination, genotypes other than those included in the vaccination program could still lead to vaginal carcinoma with unfavorable prognosis.
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| 50. |
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