| 1. |
- Schael, S, et al.
(författare)
-
Precision electroweak measurements on the Z resonance
- 2006
-
Ingår i: Physics Reports. - : Elsevier BV. - 0370-1573 .- 1873-6270. ; 427:5-6, s. 257-454
-
Forskningsöversikt (refereegranskat)abstract
- We report on the final electroweak measurements performed with data taken at the Z resonance by the experiments operating at the electron-positron colliders SLC and LEP. The data consist of 17 million Z decays accumulated by the ALEPH, DELPHI, L3 and OPAL experiments at LEP, and 600 thousand Z decays by the SLID experiment using a polarised beam at SLC. The measurements include cross-sections, forward-backward asymmetries and polarised asymmetries. The mass and width of the Z boson, m(Z) and Gamma(Z), and its couplings to fermions, for example the p parameter and the effective electroweak mixing angle for leptons, are precisely measured: m(Z) = 91.1875 +/- 0.0021 GeV, Gamma(Z) = 2.4952 +/- 0.0023 GeV, rho(l) = 1.0050 +/- 0.0010, sin(2)theta(eff)(lept) = 0.23153 +/- 0.00016. The number of light neutrino species is determined to be 2.9840 +/- 0.0082, in agreement with the three observed generations of fundamental fermions. The results are compared to the predictions of the Standard Model (SM). At the Z-pole, electroweak radiative corrections beyond the running of the QED and QCD coupling constants are observed with a significance of five standard deviations, and in agreement with the Standard Model. Of the many Z-pole measurements, the forward-backward asymmetry in b-quark production shows the largest difference with respect to its SM expectation, at the level of 2.8 standard deviations. Through radiative corrections evaluated in the framework of the Standard Model, the Z-pole data are also used to predict the mass of the top quark, m(t) = 173(+10)(+13) GeV, and the mass of the W boson, m(W) = 80.363 +/- 0.032 GeV. These indirect constraints are compared to the direct measurements, providing a stringent test of the SM. Using in addition the direct measurements of m(t) and m(W), the mass of the as yet unobserved SM Higgs boson is predicted with a relative uncertainty of about 50% and found to be less than 285 GeV at 95% confidence level. (c) 2006 Elsevier B.V. All rights reserved.
|
|
| 2. |
- Abbasi, R., et al.
(författare)
-
SEARCH FOR HIGH-ENERGY MUON NEUTRINOS FROM THE "NAKED-EYE" GRB 080319B WITH THE IceCube NEUTRINO TELESCOPE
- 2009
-
Ingår i: Astrophysical Journal. - 0004-637X .- 1538-4357. ; 701:2, s. 1721-1731
-
Tidskriftsartikel (refereegranskat)abstract
- We report on a search with the IceCube detector for high-energy muon neutrinos from GRB 080319B, one of the brightest gamma-ray bursts (GRBs) ever observed. The fireball model predicts that a mean of 0.1 events should be detected by IceCube for a bulk Lorentz boost of the jet of 300. In both the direct on-time window of 66 s and an extended window of about 300 s around the GRB, no excess was found above background. The 90% CL upper limit on the number of track-like events from the GRB is 2.7, corresponding to a muon neutrino fluence limit of 9.5 x 10(-3) erg cm(-2) in the energy range between 120 TeV and 2.2 PeV, which contains 90% of the expected events.
|
|
| 3. |
- Delorme, Richard, et al.
(författare)
-
No human tryptophan hydroxylase-2 gene R441H mutation in a large cohort of psychiatric patients and control subjects.
- 2006
-
Ingår i: Biological Psychiatry. - : Elsevier BV. - 0006-3223. ; 60:2, s. 202-203
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: It was recently reported that a rare functional variant, R441H, in the human tryptophan hydroxylase-2 gene (hTPH2) could represent an important risk factor for unipolar major depression (UP) since it was originally found in 10% of UP patients (vs. 1.4% in control subjects). METHODS: We explored the occurrence of this variation in patients with affective disorders (n = 646), autism spectrum disorders (n = 224), and obsessive-compulsive disorder (OCD) (n = 201); in healthy volunteers with no psychiatric disorders (n = 246); and in an ethnic panel of control individuals from North Africa, Sub-Saharan Africa, India, China, and Sweden (n = 277). RESULTS: Surprisingly, we did not observe the R441H variant in any of the individuals screened (3188 independent chromosomes). CONCLUSIONS: Our results do not confirm the role of the R441H mutation of the hTPH2 gene in the susceptibility to UP. The absence of the variant from a large cohort of psychiatric patients and control subjects suggests that the findings reported in the original study could be due to a genotyping error or to stratification of the initial population reported. Additional data by other groups should contribute to the clarification of the discrepancy between our results and those previous published.
|
|
| 4. |
|
|
| 5. |
- Durand, Christelle M, et al.
(författare)
-
Expression and genetic variability of PCDH11Y, a gene specific to Homo sapiens and candidate for susceptibility to psychiatric disorders.
- 2006
-
Ingår i: American Journal of Medical Genetics. Part B, Neuropsychiatric Genetics : The Official Publication of the International Society of Psychiatric Genetics. - : Wiley. - 1552-4841. ; 141:1, s. 67-70
-
Tidskriftsartikel (refereegranskat)abstract
- Synaptogenesis, the formation of functional synapses, is a crucial step for the development of the central nervous system. Among the genes involved in this process are cell adhesion molecules, such as protocadherins and neuroligins, which are essential factors for the identification of the appropriate partner cell and the formation of synapses. In this work, we studied the expression and the genetic variability of two closely related members of the protocadherin family PCDH11X/Y, located on the X and the Y chromosome, respectively. PCDH11Y is one of the rare genes specific to the hominoid lineage, being absent in other primates. Expression analysis indicated that transcripts of the PCDH11X/Y genes are mainly detected in the cortex of the human brain. Mutation screening of 30 individuals with autism identified two PCDH11Y polymorphic amino acid changes, F885V and K980N. These variations are in complete association, appeared during human evolution approximately 40,000 years ago and represent informative polymorphisms to study Y chromosome variability in populations. We studied the frequency of these variants in males with autism spectrum disorders (n = 110), attention deficit hyperactivity disorder (ADHD; n = 61), bipolar disorder (n = 61), obsessive-compulsive disorder (n = 51), or schizophrenia (n = 61) and observed no significant differences when compared to ethnically-matched control populations. These findings do not support the role of PCDH11Y, or more generally of a frequent specific Y chromosome, in the susceptibility to these neuropsychiatric disorders.
|
|
| 6. |
- Durand, Christelle. M., et al.
(författare)
-
Mutations in the gene encoding the synaptic scaffolding protein SHANK3 are associated with autism spectrum disorders.
- 2007
-
Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 39:1, s. 25-27
-
Tidskriftsartikel (refereegranskat)abstract
- SHANK3 (also known as ProSAP2) regulates the structural organization of dendritic spines and is a binding partner of neuroligins; genes encoding neuroligins are mutated in autism and Asperger syndrome. Here, we report that a mutation of a single copy of SHANK3 on chromosome 22q13 can result in language and/or social communication disorders. These mutations concern only a small number of individuals, but they shed light on one gene dosage-sensitive synaptic pathway that is involved in autism spectrum disorders.
|
|
| 7. |
- Ederth, Thomas, et al.
(författare)
-
Anomalous settlement behavior of Ulva linza zoospores on cationic oligopeptide surfaces
- 2008
-
Ingår i: Biofouling (Print). - : Informa UK Limited. - 0892-7014 .- 1029-2454. ; 24:4, s. 303-312
-
Tidskriftsartikel (refereegranskat)abstract
- Identification of settlement cues for marine fouling organisms opens up new strategies and methods for biofouling prevention, and enables the development of more effective antifouling materials. To this end, the settlement behaviour of zoospores of the green alga Ulva linza onto cationic oligopeptide self-assembled monolayers (SAMs) has been investigated. The spores interact strongly with lysine- and arginine-rich SAMs, and their settlement appears to be stimulated by these surfaces. Of particular interest is an arginine-rich oligopeptide, which is effective in attracting spores to the surface, but in a way which leaves a large fraction of the settled spores attached to the surface in an anomalous fashion. These 'pseudo-settled' spores are relatively easily detached from the surface and do not undergo the full range of cellular responses associated with normal commitment to settlement. This is a hitherto undocumented mode of settlement, and surface dilution of the arginine-rich peptide with a neutral triglycine peptide demonstrates that both normal and anomalous settlement is proportional to the surface density of the arginine-rich peptide. The settlement experiments are complemented with physical studies of the oligopeptide SAMs, before and after extended immersion in artificial seawater, using infrared spectroscopy, null ellipsometry and contact angle measurements.
|
|
| 8. |
|
|
| 9. |
- Ederth, Thomas, et al.
(författare)
-
Interactions of Zoospores of Ulva linza with Arginine-Rich Oligopeptide Monolayers
- 2009
-
Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 25:16, s. 9375-9383
-
Tidskriftsartikel (refereegranskat)abstract
- We recently reported oil the strong interactions of zoospores of the green alga, Ulva linza with all arginine-rich oligopeptide self-assembled monolayer (SAM) [Biofouling 2008, 24, 303-312], where the arginine-rich peptide induced not only high spore settlement, but also a form of abnormal settlement, or "pseudo-settlement", whereby it proportion of spores do not go through the normal process of surface exploration, adhesive exocytosis, and loss of flagella. Further. it was demonstrated that both the total number of settled spores and the fraction of pseudosettled spores were related to the surface density of the arginine-rich peptide. Here we present a further investigation of the interactions of zoospores of ulva with a set of oligomeric, de nom designed, arginine-rich peptides, specifically aimed to test the effect of peptide primary structure on the interaction. Via variations in the peptide length and by permutations in the amino acid sequences, we gain further insight into the spore-surface interactions. The interpretation of the biological assays is supported by physicochemical characterization of the SAMs using infrared spectroscopy, ellipsometry, and contact angle measurement. Results confirm the importance of arginine residues for the anomalous pseudosettlement, and we found that settlement is modulated by variations in both the total length and peptide primary structure. To elucidate the Causes of the anomalous settlement and the possible relation to peptide-membrane interactions, we also compared the settlement of the "naked" zoospores of Ulva(which present it lipoprotein membrane to the exterior without a discrete polysaccharide cell wall), with the settlement of diatoms (unicellular algae that are surrounded by it silica cell wall), onto the peptide SAMs. Cationic SAMs do not notably affect settlement (attachment), adhesion strength, or viability of diatom cells, Suggesting that the effect of the peptides on zoospores of Ulva is mediated via specific peptide-membrane interactions.
|
|
| 10. |
- Gong, Xiaohong, et al.
(författare)
-
An investigation of ribosomal protein L10 gene in autism spectrum disorders.
- 2009
-
Ingår i: BMC Medical Genetics. - : Springer Science and Business Media LLC. - 1471-2350. ; 10
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Autism spectrum disorders (ASD) are severe neurodevelopmental disorders with the male:female ratio of 4:1, implying the contribution of X chromosome genetic factors to the susceptibility of ASD. The ribosomal protein L10 (RPL10) gene, located on chromosome Xq28, codes for a key protein in assembling large ribosomal subunit and protein synthesis. Two non-synonymous mutations of RPL10, L206M and H213Q, were identified in four boys with ASD. Moreover, functional studies of mutant RPL10 in yeast exhibited aberrant ribosomal profiles. These results provided a novel aspect of disease mechanisms for autism - aberrant processes of ribosome biosynthesis and translation. To confirm these initial findings, we re-sequenced RPL10 exons and quantified mRNA transcript level of RPL10 in our samples. METHODS: 141 individuals with ASD were recruited in this study. All RPL10 exons and flanking junctions were sequenced. Furthermore, mRNA transcript level of RPL10 was quantified in B lymphoblastoid cell lines (BLCL) of 48 patients and 27 controls using the method of SYBR Green quantitative PCR. Two sets of primer pairs were used to quantify the mRNA expression level of RPL10: RPL10-A and RPL10-B. RESULTS: No non-synonymous mutations were detected in our cohort. Male controls showed similar transcript level of RPL10 compared with female controls (RPL10-A, U=81, P=0.7; RPL10-B, U=61.5, P=0.2). We did not observe any significant difference in RPL10 transcript levels between cases and controls (RPL10-A, U=531, P=0.2; RPL10-B, U=607.5, P=0.7). CONCLUSION: Our results suggest that RPL10 has no major effect on the susceptibility to ASD.
|
|
| 11. |
- Gong, Xiaohong, et al.
(författare)
-
Analysis of X chromosome inactivation in autism spectrum disorders.
- 2008
-
Ingår i: American Journal of Medical Genetics. Part B, Neuropsychiatric Genetics. - : Wiley. - 1552-485X .- 1552-4841. ; 147B:6, s. 830-835
-
Tidskriftsartikel (refereegranskat)abstract
- Autism spectrum disorders (ASD) are complex genetic disorders more frequently observed in males. Skewed X chromosome inactivation (XCI) is observed in heterozygous females carrying gene mutations involved in several X-linked syndromes. In this study, we aimed to estimate the role of X-linked genes in ASD susceptibility by ascertaining the XCI pattern in a sample of 543 informative mothers of children with ASD and in a sample of 163 affected girls. The XCI pattern was also determined in two control groups (144 adult females and 40 young females) with a similar age distribution to the mothers sample and affected girls sample, respectively. We observed no significant excess of skewed XCI in families with ASD. Interestingly, two mothers and one girl carrying known mutations in X-linked genes (NLGN3, ATRX, MECP2) showed highly skewed XCI, suggesting that ascertainment of XCI could reveal families with X-linked mutations. Linkage analysis was carried out in the subgroup of multiplex families with skewed XCI (> or = 80:20) and a modest increased allele sharing was obtained in the Xq27-Xq28 region, with a peak Z-score of 1.75 close to rs719489. In summary, our results suggest that there is no major X-linked gene subject to XCI and expressed in blood cells conferring susceptibility to ASD. However, the possibility that rare mutations in X-linked genes could contribute to ASD cannot be excluded. We propose that the XCI profile could be a useful criteria to prioritize families for mutation screening of X-linked candidate genes.
|
|
| 12. |
- Melke, Jonas, 1971, et al.
(författare)
-
Abnormal melatonin synthesis in autism spectrum disorders.
- 2008
-
Ingår i: Molecular Psychiatry. - : Springer Science and Business Media LLC. - 1359-4184 .- 1476-5578. ; 13:1, s. 90-98
-
Tidskriftsartikel (refereegranskat)abstract
- Melatonin is produced in the dark by the pineal gland and is a key regulator of circadian and seasonal rhythms. A low melatonin level has been reported in individuals with autism spectrum disorders (ASD), but the underlying cause of this deficit was unknown. The ASMT gene, encoding the last enzyme of melatonin synthesis, is located on the pseudo-autosomal region 1 of the sex chromosomes, deleted in several individuals with ASD. In this study, we sequenced all ASMT exons and promoters in individuals with ASD (n=250) and compared the allelic frequencies with controls (n=255). Non-conservative variations of ASMT were identified, including a splicing mutation present in two families with ASD, but not in controls. Two polymorphisms located in the promoter (rs4446909 and rs5989681) were more frequent in ASD compared to controls (P=0.0006) and were associated with a dramatic decrease in ASMT transcripts in blood cell lines (P=2 x 10(-10)). Biochemical analyses performed on blood platelets and/or cultured cells revealed a highly significant decrease in ASMT activity (P=2 x 10(-12)) and melatonin level (P=3 x 10(-11)) in individuals with ASD. These results indicate that a low melatonin level, caused by a primary deficit in ASMT activity, is a risk factor for ASD. They also support ASMT as a susceptibility gene for ASD and highlight the crucial role of melatonin in human cognition and behavior.
|
|
| 13. |
- Nygren, Patrik, 1979-
(författare)
-
Structural and Functional Studies of De Novo Designed Peptides at Surfaces
- 2008
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The work presented in this thesis deals with the structural and functional properties of peptides at surfaces. The interaction of peptides with surfaces is an ever so common occurrence in our every day life, from the bug squashed on the windshield of our car to the barnacle on our boat, and from the blood plasma used in the hospital to the proteins in our cells. The effect these occurrences has on our lives is diverse, the bug is annoying whereas the barnacle settlement of ship hull is costly for marine transportation, the blood plasma contains components of vital importance for our immunological defense system and the proteins in our cells are crucial for regulatory processes and life.One part of this thesis, performed as a part of the EU-founded project AMBIO, deals with the concept of marine biofouling. A number of short peptides have been designed, synthesized, and used to investigate their effect on the settlement on marine biofoulers, such as the Ulva linza algae and the Navicula diatom, on template surfaces coated with thin layers of these molecules. The surfaces have been thoroughly investigated with respect of their physio-chemical properties before and after submersion in artificial seawater and ultimately in suspensions containing the organisms. The most interesting results were obtained with an arginine-rich peptide coating that when introduced to Ulva linza zoospores, displayed extensive settlement, compared to reference surfaces. In addition, a large fraction of the settled spores had an abnormal morphology.The other part of this thesis is focused on designed peptides that when adsorbed on a negatively charged surface adopts a well-defined secondary structure, either α-helical or β-sheet. Precisely placed amino acids in the peptides will strongly disfavor structure in solution, primarily due to electrostatic repulsion, but when the peptides are adsorbed on the negatively charged surfaces, they adopt a well-defined secondary structure due to ion pair bonding. These interactions have been thoroughly investigated by systematic variations of the side-chains. In order to determine the factors contributing to the induced structure, several peptides with different amino acid sequences have been synthesized. Factors that have been investigated include 1) the positive charge density, 2) distribution of positive charges, 3) negative charge density, 4) increasing hydrophobicity, and 5) incorporating amino acids with different helix propensities. Moreover, pH dependence and the effect of different interaction partners have also been investigated. It has also been shown that the system can be modified to incorporate a catalytic site that is only active when the helix is formed. This research will increase our understanding of peptide-surface interactions and might be of importance for both bionanotechnology and medicine.
|
|
| 14. |
- Nygren, Thomas, 1972-
(författare)
-
Erfarna lärares historiedidaktiska insikter och undervisningsstrategier
- 2009
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aim of this study has been to investigate, through the narratives of ex-perienced teachers, insights and strategies in the teaching of history in upper secondary school. Based on a flexible grounded theory, life history and theories of pedagogical content knowledge, seven experienced history teachers have been interviewed about their conceptions of history teaching.Development of insights into history teaching and the formation of knowledge can be described as involving both a refinement of practice and more revolutionary turning points. These insights emphasize that good knowledge of the subject is central for legitimacy and creativity. History teaching in Sweden is described as increasingly international and contem-porary, and focussed on students’ learning from various points of view. Varied teaching is stressed with the teacher in centre and also being able to take the role of arranger. Of importance is also the handling of teaching in history as a foundation course as well as an advanced or specialized course.Influences from other subjects have had a diverse impact at the same time as personal interests and experiences, as well as external influences, have been important for the development of strategies. History teachers’ teaching strategies may be described in terms of 1) multiperspectivity, where different points of view and interpretations of history are central; 2) narrative history, where through both major and minor stories, a chronological structure and animation of the subject of history are strived after; 3) social scientific history, which uses history to explain contemporary society through making comparisons and seeking general patterns; and 4) an eclectic strategy, which strives after varieties of an individualised teaching of history by allowing students to make their ways into history in diverse ways. The experienced history teachers’ narratives make evident how the subject of history can be transformed, they demonstrate different conceivable ways of teaching history and reveal its complexity.The teachers’ narratives show how, through their strategies in interaction with their insights in history teaching, they have created an overview and structure in the complex reality of teaching history. The teachers’ insights and strategies constitute a practice based contribution to a more experience informed practice and research on the teaching of history.
|
|
| 15. |
- Nygren, Thomas, 1972-
(författare)
-
Historielärare
- 2009
-
Ingår i: Ämnesdidaktiska insikter och strategier. - Karlstad : Karlstad University Press. - 9789185335930 ; , s. 119-156
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)
|
|
| 16. |
|
|
| 17. |
- Nygren, Thomas, 1972-
(författare)
-
Se och lär av proffsen! : teori och metod för forskning i historieundervisningens praktik
- 2007
-
Ingår i: Rum för forskning - rymd för lärande. - Umeå : Fakultetsnämnden för lärarutbildning, Umeå universitet. - 9789172643185 ; , s. 64-84
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- The gap between theory and practice in teaching needs to be closed. This is a plan for how a combination of theories of education, history and pedagogical content knowledge can be used in the study of history teaching. By using this theory and method of inquiry the strategies for history teaching will be made visible, which will enable us better to see, understand and appreciate knowledge gained through practice. The strategies will show how teaching has filled the “missing paradigm” and how teachers have experienced and used their professional freedom. Many theories as well as teacher training have been criticised for being too far from reality. By conducting this kind of research theory and practice can meet with mutual benefit for science and for the reflective practitioner.
|
|
| 18. |
- Nygren, Thomas
(författare)
-
Vis av erfarenhet : olika strategier för undervisning i historia
- 2007
-
Ingår i: Eskilsson, Olle, Redfors, Andreas (red.), Ämnesdidaktik ur ett nationellt och internationellt perspektiv. - Kristianstad : Kristianstad University Press. - 9197396443 ; , s. 209-220
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)
|
|
| 19. |
|
|
| 20. |
- Schneider, Thomas, et al.
(författare)
-
Evaluation and control of occupational health risks from nanoparticles
- 2007
-
Rapport (refereegranskat)abstract
- Rapid growth in the nanoparticle industry is anticipated in the Nordic countries owing to highly focused national research and investment initiatives. Knowledge on consequences for occupational exposures to engineered nanoparticles and appropriate technical control levels is still limited. This report explores existing knowledge on exposure risks and technical control approaches. The report concludes that data are too limited to allow general conclusions to be drawn regarding risks of exposure to engineered nanoparticles.Engineering techniques for controlling nanoparticle exposure can build on the current knowledge and approaches to control exposure to e.g. welding fume and carbon black. There is a need for improving the quality of information provided in Material Safety Data Sheets.
|
|
| 21. |
- Taussig, Michael J., et al.
(författare)
-
ProteomeBinders : planning a European resource of affinity reagents for analysis of the human proteome
- 2007
-
Ingår i: Nature Methods. - : Springer Science and Business Media LLC. - 1548-7091 .- 1548-7105. ; 4:1, s. 13-17
-
Tidskriftsartikel (refereegranskat)abstract
- ProteomeBinders is a new European consortium aiming to establish a comprehensive resource of well-characterized affinity reagents, including but not limited to antibodies, for analysis of the human proteome. Given the huge diversity of the proteome, the scale of the project is potentially immense but nevertheless feasible in the context of a pan-European or even worldwide coordination.
|
|
