Mutation in CEP63 co-segregating with developmental dyslexia in a Swedish family

Developmental dyslexia is the most common learning disorder in children. Problems in reading and writing are likely due to a complex interaction of genetic and environmental factors, resulting in reduced power of studies of the genetic factors underlying developmental dyslexia. Our approach in the current study was to perform exome sequencing of affected and unaffected individuals within an extended pedigree with a familial form of developmental dyslexia. We identified a two-base mutation, causing a p.R229L amino acid substitution in the centrosomal protein 63 kDa (CEP63), co-segregating with developmental dyslexia in this pedigree. This mutation is novel, and predicted to be highly damaging for the function of the protein. 3D modelling suggested a distinct conformational change caused by the mutation. CEP63 is localised to the centrosome in eukaryotic cells and is required for maintaining normal centriole duplication and control of cell cycle progression. We found that a common polymorphism in the CEP63 gene had a significant association with brain white matter volume. The brain regions were partly overlapping with the previously reported region influenced by polymorphisms in the dyslexia susceptibility genes DYX1C1 and KIAA0319. We hypothesise that CEP63 is particularly important for brain development and might control the proliferation and migration of cells when those two events need to be highly coordinated.Peer reviewe

Deltagerdriven forskning – växtodlingsgruppen: Resultat och utvärdering av arbetet under 1998 till 2001

De ekologiska lantbrukarna i Sverige har under lång tid utfört olika typer av utvecklingsarbete på gårdsnivå (Wivstad, 1999). I den fortsatta utvecklingen av ekologiskt lantbruk är det viktigt att ta tillvara dessa erfarenheter och kunskaper. Deltagardriven forskning är en förändringsprocess (Ullmark, 1998) där aktiva lantbrukare, rådgivare och forskare arbetar i grupp utifrån gemensamma intresseområden. Syftet är att knyta ihop forskarnas, rådgivarnas och lantbrukarnas teoretiska och praktiska kunskaper och erfarenheter. Alla som medverkar i processen är lika viktiga och alla parter som berörs av resultaten har möjlighet att påverka gruppens arbete och utveckling (Ullmark, 1998). Tillsammans identifierar gruppen problem och använder/utvecklar för lantbrukaren relevanta försöks- och forskningsmetoder som kan bidra till att lösa de praktiska problem som lantbrukaren faktiskt ställs inför. Genom deltagardriven forskning kan lantbrukarna även få möjlighet till att påverka var och hur forskning bedrivs. Forskningsfrågorna kan hämtas från lantbrukssystemets olika delar samt göra gruppen medveten om hur olika delar påverkar helheten (Wivstad, 1999; Eksvärd et al, 2001). I förlängningen kan deltagarna bli informatörer och överföra idéer till andra lantbrukare (Ullmark, 1998). Centrum för uthålligt lantbruk, CUL, placerat vid SLU, har sedan 1998 ansvarat för det tvärvetenskapliga projektet ”Deltagardriven forskning” som ett verktyg för regional utveckling av det ekologiska lantbruket. Det övergripande målet har varit att öka kunskapen om hur man kan åstadkomma uthålliga lantbrukssystem. Projektet startade med sex delgrupper inriktade på följande områden: grönsaker – friland, grönsaker – växthus, höns, växtodling, biogas samt grisproduktion. Därefter har några tillkommit och några avslutats. För aktuell information se hemsidan: www.cul.slu.se. Ytterligare beskrivning kan fås i ”Deltagardriven forskning – forskningsinriktad aktörssamverkan för svenskt lantbruk” (Eksvärd, i tryck)

In-situ ESEM study of thermal-mechanical fatigue crack propagation

An experimental procedure to determine crack propagation rates under thermo-mechanical loading is presented. The experiments were conducted in-situ within an environmental scanning electron microscope, and images of the crack tip region were taken throughout the load cycles. The mechanical load was provided by a load controlled electrically driven load stage. Thermal heating of the crack region was provided by means of resistance heating, and cooling by water flowing through the grips holding the specimen. In-phase experiments with the mechanical load following the temperature, as well as out-of-phase experiments with maximum mechanical load coinciding with minimum temperature, were conducted. Temperature cycles with a range from 300 degrees C to 550 degrees C, and from 300 degrees C to 630 degrees C with cycle times of 55 s and 75 s, respectively, were performed. Crack propagation rates as well as fracture surface morphologies were compared with corresponding results obtained under iso-thermal conditions at 550 degrees C and 630 degrees C. It was found that the temperature at which maximum mechanical load was applied was decisive for both the crack propagation rate and the fracture surface morphology, regardless of whether the temperature was cycled or kept constant. The study indicates that iso-thermal fatigue propagation data can be used to predict crack propagation rates provided that iso-thermal data are taken from the temperature at which the mechanical load peaks are known. (C) 2008 Elsevier B.V. All rights reserved

SEM study of overload effects during fatigue crack growth using an image analyzing technique and potential drop measures

To study the mechanisms affecting the crack propagation rate for fatigue cracks exposed to an overload, an in situ scanning electron microscope technique was used, together with potential drop measurements. High-resolution images were analysed with an image analysis program to measure the displacements along the crack, and the potential drop technique was employed to measure the electrical contact between the fatigue crack surfaces. The crack closure level could, by image analysis, be determined as close as 1 μm from the crack tip. The indications from the image analysis pointed towards a somewhat lower closure load as compared to the potential drop technique. The effect of an overload on the crack propagation rate was found to depend on the magnitude of the overload in combination with the steady-state conditions. Both overload induced crack retardation and crack acceleration was noticed to occur. [ABSTRACT FROM AUTHOR

A unified picture of static and dynamic length scales in polymer solutions

After a thorough study of static and dynamic properties of polystyrene solution, and taking into account the local solvent viscosity, an incontrovertible support for the applicability of blob model from semidilute to high concentrated solutions, is presented. The study demonstrates the functionability of the blob model in predicting III/IV crossovers as a consequence of rodlike structure of the partial chain. The study predicts the theoritical picture of the length scales valid for highly concentrated solutions, with local solvent viscosity taken into account. The present study is also applicable to various macromolecular systems, including DNA and actin filament over wide range of polymer concentrations