| 1. |
- Aad, G., et al.
(författare)
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- 2013
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Ingår i: Journal of Instrumentation. - 1748-0221. ; 8
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Tidskriftsartikel (refereegranskat)
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| 2. |
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| 3. |
- Joshi, Peter K, et al.
(författare)
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Directional dominance on stature and cognition in diverse human populations
- 2015
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 523:7561, s. 459-462
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Tidskriftsartikel (refereegranskat)abstract
- Homozygosity has long been associated with rare, often devastating, Mendelian disorders, and Darwin was one of the first to recognize that inbreeding reduces evolutionary fitness. However, the effect of the more distant parental relatedness that is common in modern human populations is less well understood. Genomic data now allow us to investigate the effects of homozygosity on traits of public health importance by observing contiguous homozygous segments (runs of homozygosity), which are inferred to be homozygous along their complete length. Given the low levels of genome-wide homozygosity prevalent in most human populations, information is required on very large numbers of people to provide sufficient power. Here we use runs of homozygosity to study 16 health-related quantitative traits in 354,224 individuals from 102 cohorts, and find statistically significant associations between summed runs of homozygosity and four complex traits: height, forced expiratory lung volume in one second, general cognitive ability and educational attainment (P < 1 × 10(-300), 2.1 × 10(-6), 2.5 × 10(-10) and 1.8 × 10(-10), respectively). In each case, increased homozygosity was associated with decreased trait value, equivalent to the offspring of first cousins being 1.2 cm shorter and having 10 months' less education. Similar effect sizes were found across four continental groups and populations with different degrees of genome-wide homozygosity, providing evidence that homozygosity, rather than confounding, directly contributes to phenotypic variance. Contrary to earlier reports in substantially smaller samples, no evidence was seen of an influence of genome-wide homozygosity on blood pressure and low density lipoprotein cholesterol, or ten other cardio-metabolic traits. Since directional dominance is predicted for traits under directional evolutionary selection, this study provides evidence that increased stature and cognitive function have been positively selected in human evolution, whereas many important risk factors for late-onset complex diseases may not have been.
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| 4. |
- Hägglund, Carl, 1975-, et al.
(författare)
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Growth, intermixing, and surface phase formation for zinc tin oxide nanolaminates produced by atomic layer deposition
- 2016
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Ingår i: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films. - : American Vacuum Society. - 0734-2101 .- 1520-8559. ; 34:2
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Tidskriftsartikel (refereegranskat)abstract
- A broad and expanding range of materials can be produced by atomic layer deposition at relatively low temperatures, including both oxides and metals. For many applications of interest, however, it is desirable to grow more tailored and complex materials such as semiconductors with a certain doping, mixed oxides, and metallic alloys. How well such mixed materials can be accomplished with ALD requires knowledge of the conditions under which the resulting films will be mixed, solid solutions, or laminated. The growth and lamination of zinc oxide and tin oxide is studied here by means of the extremely surface sensitive technique of low energy ion scattering, combined with bulk composition and thickness determination, and X-ray diffraction. At the low temperatures used for deposition (150 °C) there is little evidence for atomic scale mixing even with the smallest possible bilayer period, and instead a morphology with small ZnO inclusions in a SnOx matrix is deduced. Post-annealing of such laminates above 400 °C however produces a stable surface phase with a 30% increased density. From the surface stoichiometry, this is likely the inverted spinel of zinc stannate, Zn2SnO4. Annealing to 800 °C results in films containing crystalline Zn2SnO4, or multilayered films of crystalline ZnO, Zn2SnO4 and SnO2 phases, depending on the bilayer period.
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| 6. |
- Birch, Jens
(författare)
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Single-crystal Mo/V superlattices : growth, structure, and hydrogen uptake
- 1994
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Fundamental studies concerning the growth, structural characterization and hydrogen uptake of single-crystal (00 l )-oriented Mo/V superlattices have been performed. The superlattices were grown by dual-target magnetron sputtering in pure Ar-atmosphere < 6·10-3 Torr on (001)-oriented MgO substrates. X-ray diffraction (XRD), X-ray and neutron reflectivity, high resolution (HR) as well as ordinary crosssectional transmission electron microscopy (XTEM) and selected area electron diffraction (SAED) were used for the structural characterization. Hydrogen depth-profiling was performed by the 15N method.For growth of periodic Mo/V superlattices, it is shown that substrate temperatures in the range of 600-700 °C is feasible for epitaxy. At higher growth temperatures substantial interdiffusion occurred. Furthermore, simulations of XRDpatterns gave the width of the interfaces to be ±1 monolayer (±0,154 nm) which was confirmed by XRD and HRXTEM analyses of a superlattice grown with layer thicknesses DMo=Dv=0,31 nm (2 monolayers). A transition from smooth to wavy V-layers was found to occur at a critical V-layer thickness Dc. In superlattices where the relative amount of V is large, De is large and vice versa for superlattices containing thin V-layers. In superlattices with equally thick Mo- and V-layers Dc was found to be ~2,5 nm. Mo was found to grow with a uniform thickness following the surface of the V-layers. The layer thickness fluctuations are non-accumulative and disappear if the periodicity of a growing Mo/V superlattice is changed so that Dv becomes smaller than Dc. The origin of the 3D evolution is explained in terms of surface strain and the roughening transition. The interfaces of Mo/V superlattices grown under the influence of energetic ion bombardment ranging from about 15 eV to 250 eV was studied by HRXTEM and XRD. Both techniques indicated a continous deterioration of the interface quality and an increasing amount of defects with increasing ion energy.The diffraction peaks from a clas of quasi-periodic superlattices which can be generated by the inflation rules A→AmB, B→A (m = positive integer) was analytically, experimentally and numerically found to be located at the wavevectors q = 2πɅ-1rγ(m)k where r and k are integers and A is an average superlattice period. The ratios, γ(m), between the thicknesses of the two superlattice building blocks, A and B, must be chosen such that γ(m) = (m + (m2 + 4) 1/2 )/2.The uptake of hydrogen in the superlattices is found to decrease with decreasing A and for ≤5,5 nm the transition between α-VHx and β-VHx is not observed. A model is proposed which explains the A-dependent behaviour of the hydrogen uptake by a transfer of interstitial electrons from Mo to V, creating a 0,49 nm wide H-free interface layer. The existence of this layer is shown both by the 15N method performed on samples containing several A:s and by combining simulations of X-ray and neutron reflectivities with measurements on superlattices loaded with either hydrogen or deuterium. The structural change of Mo/V(OOl) superlattices upon H-loading was measured by a method derived in this work which utilises a combination of X-ray reflectivity and reciprocal space mapping by XRD. The lattice parameters in the layers are measured in the growth direction as well a in the plane of the sample. It is found that the V lattice expands in the growth direction and that the hydrogenation process is associated with relaxation of coherency strain.
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