| 1. |
- Menkveld, Albert J., et al.
(författare)
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Nonstandard Errors
- 2024
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Ingår i: JOURNAL OF FINANCE. - : Wiley-Blackwell. - 0022-1082 .- 1540-6261. ; 79:3, s. 2339-2390
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Tidskriftsartikel (refereegranskat)abstract
- In statistics, samples are drawn from a population in a data-generating process (DGP). Standard errors measure the uncertainty in estimates of population parameters. In science, evidence is generated to test hypotheses in an evidence-generating process (EGP). We claim that EGP variation across researchers adds uncertainty-nonstandard errors (NSEs). We study NSEs by letting 164 teams test the same hypotheses on the same data. NSEs turn out to be sizable, but smaller for more reproducible or higher rated research. Adding peer-review stages reduces NSEs. We further find that this type of uncertainty is underestimated by participants.
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| 2. |
- Schijven, Dick, et al.
(författare)
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Large-scale analysis of structural brain asymmetries in schizophrenia via the ENIGMA consortium
- 2023
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences (PNAS). - 0027-8424 .- 1091-6490. ; 120:14
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Tidskriftsartikel (refereegranskat)abstract
- Left-right asymmetry is an important organizing feature of the healthy brain that may be altered in schizophrenia, but most studies have used relatively small samples and heterogeneous approaches, resulting in equivocal findings. We carried out the largest case-control study of structural brain asymmetries in schizophrenia, with MRI data from 5,080 affected individuals and 6,015 controls across 46 datasets, using a single image analysis protocol. Asymmetry indexes were calculated for global and regional cortical thickness, surface area, and subcortical volume measures. Differences of asymmetry were calculated between affected individuals and controls per dataset, and effect sizes were meta-analyzed across datasets. Small average case-control differences were observed for thickness asymmetries of the rostral anterior cingulate and the middle temporal gyrus, both driven by thinner left-hemispheric cortices in schizophrenia. Analyses of these asymmetries with respect to the use of antipsychotic medication and other clinical variables did not show any significant associations. Assessment of age- and sex-specific effects revealed a stronger average leftward asymmetry of pallidum volume between older cases and controls. Case-control differences in a multivariate context were assessed in a subset of the data (N = 2,029), which revealed that 7% of the variance across all structural asymmetries was explained by case-control status. Subtle case-control differences of brain macrostructural asymmetry may reflect differences at the molecular, cytoarchitectonic, or circuit levels that have functional relevance for the disorder. Reduced left middle temporal cortical thickness is consistent with altered left-hemisphere language network organization in schizophrenia.
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| 3. |
- Schunkert, Heribert, et al.
(författare)
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Large-scale association analysis identifies 13 new susceptibility loci for coronary artery disease
- 2011
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1546-1718 .- 1061-4036. ; 43:4, s. 153-333
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Tidskriftsartikel (refereegranskat)abstract
- We performed a meta-analysis of 14 genome-wide association studies of coronary artery disease (CAD) comprising 22,233 individuals with CAD (cases) and 64,762 controls of European descent followed by genotyping of top association signals in 56,682 additional individuals. This analysis identified 13 loci newly associated with CAD at P < 5 x 10(-8) and confirmed the association of 10 of 12 previously reported CAD loci. The 13 new loci showed risk allele frequencies ranging from 0.13 to 0.91 and were associated with a 6% to 17% increase in the risk of CAD per allele. Notably, only three of the new loci showed significant association with traditional CAD risk factors and the majority lie in gene regions not previously implicated in the pathogenesis of CAD. Finally, five of the new CAD risk loci appear to have pleiotropic effects, showing strong association with various other human diseases or traits.
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| 4. |
- Berger, Urs, et al.
(författare)
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Recent developments in trace analysis of poly- and perfluoroalkyl substances
- 2011
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Ingår i: Analytical and Bioanalytical Chemistry. - : Springer Science and Business Media LLC. - 1618-2642 .- 1618-2650. ; 400:6, s. 1625-1635
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Tidskriftsartikel (refereegranskat)abstract
- Recent developments, improvements, and trends in the ultra-trace determination of per- and polyfluoroalkyl substances (PFASs) in environmental and human samples are highlighted and the remaining challenges and uncertainties are outlined and discussed. Understanding the analytical implications of such things as adsorption of PFASs to surfaces, effects of differing matrices, varying PFAS isomer response factors, potential bias effects of sampling, sample preparation, and analysis is critical to measuring highly fluorinated compounds at trace levels. These intricate analytical issues and the potential consequences of ignoring to deal with them correctly are discussed and documented with examples. Isomer-specific analysis and the development of robust multi-chemical methods are identified as topical trends in method development for an ever-increasing number of PFASs of environmental and human interest. Ultimately, the state-of-the-art of current analytical method accuracy is discussed on the basis of results from interlaboratory comparison studies.
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| 5. |
- Björk, Stefan, 1972-
(författare)
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Män möter mödravård : om betydelsen av "vi" i mötet med mödrahälsovård, förlossningsvård och BB-vård
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- I dagens Sverige är det en självklarhet att blivande pappor skall vara delaktiga och engagerade i graviditet, förlossning och omvårdnad av det nyfödda barnet. De flesta pappor är med vid besöken på barnmorskemottagningen inklusive ultraljudsundersökningen, deltar i föräldrautbildningen och är med vid barnets födelse. Ändå uttrycker många pappor missnöje med mödrahälsovården, förlossningsvården och BB-vården. När de tillfrågas om saken uppger de ofta att de känner sig utanför, osynliga och ovidkommande. Den här studien är ett försök att bättre förstå de upplevelserna.Studien grundar sig på intervjuer med tio svenska pappor. Pappornas berättelser om mötet med mödrahälsovården, förlossningsvården och BB-vården analyserades med en narrativ forskningsansats där särskilt fokus lades på hur de i berättelsen förekommande personerna framställdes eller positionerades.Avhandlingens resultat kan sammanfattas i tre punkter: (1) Mödrahälsovårdens fokus på de fysiska aspekterna av graviditet och förlossning innebär att den blivande/nyblivna pappan kan ha svårt att finna en meningsfull plats eller position i mötet med mödrahälsovård, förlossningsvård och BB-vård. (2) De intervjuade pappornas berättelser om dessa möten kan grovt sett indelas i "vi"-berättelser där pappan fann en obesvärad position och "jag"-berättelser där han inte gjorde det. Detta har jag tolkat som att papporna i dessa möten eftersträvade en "vi"-position där graviditet och förlossning kunde bli en för mamman och pappan gemensam angelägenhet. (3) Svårigheten att finna en obesvärad position i mötet med mödrahälsovård, förlossningsvård och BB-vård har i första hand att göra med att den blivande/nyblivna pappan inte är gravid, inte att han är man. Det är huruvida kroppen är gravid eller inte gravid som skapar gränsen, inte vilket kön kroppen har. Den sökta "vi"-positionen kan därför betecknas som könsirrelevant.En slutsats är att om mödrahälsovård, förlossningsvård och BB-vård vill göra den blivande mammans partner verkligt delaktig i graviditet, förlossning och spädbarnsomvårdnad är den relevanta frågan: hur kan man bidra till att den blivande/nyblivna mammans partner kan finna en position som bättre inkluderar honom/henne i detta möte? En möjlig sådan position är den i denna studie påvisade "vi"-position där graviditet, förlossning och spädbarnsomvårdnad är en för båda föräldrarna gemensam angelägenhet. Att ge plats för en "vi"-position innebär också att sträcka ut tidsperspektivet från graviditetens här-och-nu förbi den annalkande förlossningen till det som kommer därefter: föräldraskapet -- oavsett vem som har varit gravid.
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| 6. |
- Cristal, Adrian, et al.
(författare)
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LEGaTO: First Steps Towards Energy-Efficient Toolset for Heterogeneous Computing
- 2018
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Ingår i: ACM International Conference Proceeding Series. - New York, NY, USA : ACM. ; , s. 210-217
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Konferensbidrag (refereegranskat)abstract
- LEGaTO is a three-year EU H2020 project which started in December 2017. The LEGaTO project will leverage task-based programming models to provide a software ecosystem for Made-in-Europe heterogeneous hardware composed of CPUs, GPUs, FPGAs and dataflow engines. The aim is to attain one order of magnitude energy savings from the edge to the converged cloud/HPC.
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| 7. |
- Cristal, Adrian, et al.
(författare)
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LEGaTO: Towards Energy-Efficient, Secure, Fault-tolerant Toolset for Heterogeneous Computing
- 2018
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Ingår i: Proceedings of the 15th ACM International Conference on Computing Frontiers. - New York, NY, USA : ACM. - 9781450357616 ; , s. 276-278
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Konferensbidrag (refereegranskat)abstract
- LEGaTO is a three-year EU H2020 project which started in December 2017. The LEGaTO project will leverage task-based programming models to provide a software ecosystem for Made-in-Europe heterogeneous hardware composed of CPUs, GPUs, FPGAs and dataflow engines. The aim is to attain one order of magnitude energy savings from the edge to the converged cloud/HPC.
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| 8. |
- Dimopoulos, Meletios A., et al.
(författare)
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Safety and efficacy of pomalidomide plus low-dose dexamethasone in STRATUS (MM-010) : A phase 3b study in refractory multiple myeloma
- 2016
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Ingår i: Blood. - : American Society of Hematology. - 0006-4971 .- 1528-0020. ; 128:4, s. 497-503
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Tidskriftsartikel (refereegranskat)abstract
- Patients with relapsed and/or refractory multiple myeloma (RRMM) have poor prognosis. The STRATUS study assessed safety and efficacy of pomalidomide plus low-dose dexamethasone in the largest cohort to date of patients with RRMM. Patients who failed treatment with bortezomib and lenalidomide and had adequate prior alkylator therapy were eligible. Pomalidomide 4 mg was given on days 1-21 of 28-day cycles with low-dose dexamethasone 40 mg (20 mg for patients aged >75 years) on days 1, 8, 15, and 22 until progressive disease or unacceptable toxicity. Safety was the primary end point; secondary end points included overall response rate (ORR), duration of response (DOR), progression-free survival (PFS), and overall survival (OS). Among 682 patients enrolled, median age was 66 years, and median time since diagnosis was 5.3 years. Median number of prior regimens was 5. Most patients were refractory to both lenalidomide and bortezomib (80.2%). Median follow-up was 16.8 months; median duration of treatment was 4.9 months. Most frequent grade 3/4 treatment-emergent adverse events were hematologic (neutropenia [49.7%], anemia [33.0%], and thrombocytopenia [24.1%]). Most common grade 3/4 nonhematologic toxicities were pneumonia (10.9%) and fatigue (5.9%). Grade 3/4 venous thromboembolism and peripheral neuropathy were rare (1.6% each). The ORR was 32.6%, and the median DOR was 7.4 months. Median PFS and OS were 4.6 months and 11.9 months, respectively. We present the largest trial to date evaluating pomalidomide plus low-dose dexamethasone in patients with RRMM, further confirming that this regimen offers clinically meaningful benefit and is generally well tolerated. www.Clinicaltrials.gov identifier NCT01712789.
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| 9. |
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| 10. |
- Gifford, Robert, et al.
(författare)
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Temporal pessimism and spatial optimism in environmental assessments: An 18-nation study
- 2009
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Ingår i: Journal of Environmental Psychology. - : Elsevier BV. - 0272-4944. ; 29, s. 1-12
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Tidskriftsartikel (refereegranskat)abstract
- The personal assessments of the current and expected future state of the environment by 3232 community respondents in 18 nations were investigated at the local, national, and global spatial levels. These assessments were compared to a ranking of each country's environmental quality by an expert panel. Temporal pessimism (“things will get worse”) was found in the assessments at all three spatial levels. Spatial optimism bias (“things are better here than there”) was found in the assessments of current environmental conditions in 15 of 18 countries, but not in the assessments of the future. All countries except one exhibited temporal pessimism, but significant differences between them were common. Evaluations of current environmental conditions also differed by country. Citizens' assessments of current conditions, and the degree of comparative optimism, were strongly correlated with the expert panel's assessments of national environmental quality. Aside from the value of understanding global trends in environmental assessments, the results have important implications for environmental policy and risk management strategies.
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| 11. |
- Haase, Tina, et al.
(författare)
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G protein-coupled receptor 15 expression is associated with myocardial infarction
- 2023
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Ingår i: International Journal of Molecular Sciences. - : MDPI. - 1661-6596 .- 1422-0067. ; 24:1
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Tidskriftsartikel (refereegranskat)abstract
- Beyond the influence of lifestyle-related risk factors for myocardial infarction (MI), the mechanisms of genetic predispositions for MI remain unclear. We sought to identify and characterize differentially expressed genes in early-onset MI in a translational approach. In an observational case–control study, transcriptomes from 112 early-onset MI individuals showed upregulated G protein-coupled receptor 15 (GPR15) expression in peripheral blood mononuclear cells compared to controls (fold change = 1.4, p = 1.87 × 10−7). GPR15 expression correlated with intima-media thickness (β = 0.8498, p = 0.111), C-reactive protein (β = 0.2238, p = 0.0052), ejection fraction (β = −0.9991, p = 0.0281) and smoking (β = 0.7259, p = 2.79 × 10−10). The relation between smoking and MI was diminished after the inclusion of GPR15 expression as mediator in mediation analysis (from 1.27 (p = 1.9 × 10−5) to 0.46 (p = 0.21)). The DNA methylation of two GPR15 sites was 1%/5% lower in early-onset MI individuals versus controls (p = 2.37 × 10−6/p = 0.0123), with site CpG3.98251219 significantly predicting risk for incident MI (hazard ratio = 0.992, p = 0.0177). The nucleotide polymorphism rs2230344 (C/T) within GPR15 was associated with early-onset MI (odds ratio = 3.61, p = 0.044). Experimental validation showed 6.3-fold increased Gpr15 expression in an ischemic mouse model (p < 0.05) and 4-fold increased Gpr15 expression in cardiomyocytes under ischemic stress (p < 0.001). After the induction of MI, Gpr15gfp/gfp mice showed lower survival (p = 0.042) and deregulated gene expression for response to hypoxia and signaling pathways. Using a translational approach, our data provide evidence that GPR15 is linked to cardiovascular diseases, mediating the adverse effects of smoking.
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| 12. |
- Hofer, M., et al.
(författare)
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International periodic fever, aphthous stomatitis, pharyngitis, cervical adenitis syndrome cohort: description of distinct phenotypes in 301 patients
- 2014
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Ingår i: Rheumatology. - : Oxford University Press (OUP). - 1462-0324 .- 1462-0332. ; 53:6, s. 1125-1129
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Tidskriftsartikel (refereegranskat)abstract
- Objectives. The aims of this study were to describe the clinical features of periodic fever, aphthous stomatitis, pharyngitis and cervical adenitis (PFAPA) and identify distinct phenotypes in a large cohort of patients from different countries. Methods. We established a web-based multicentre cohort through an international collaboration within the periodic fevers working party of the Pediatric Rheumatology European Society (PReS). The inclusion criterion was a diagnosis of PFAPA given by an experienced paediatric rheumatologist participating in an international working group on periodic fever syndromes. Results. Of the 301 patients included from the 15 centres, 271 had pharyngitis, 236 cervical adenitis, 171 oral aphthosis and 132 with all three clinical features. A total of 228 patients presented with additional symptoms (131 gastrointestinal symptoms, 86 arthralgias and/or myalgias, 36 skin rashes, 8 neurological symptoms). Thirty-one patients had disease onset after 5 years and they reported more additional symptoms. A positive family history for recurrent fever or recurrent tonsillitis was found in 81 patients (26.9%). Genetic testing for monogenic periodic fever syndromes was performed on 111 patients, who reported fewer occurrences of oral aphthosis or additional symptoms. Twenty-four patients reported symptoms (oral aphthosis and malaise) outside the flares. The CRP was >50 mg/l in the majority (131/190) of the patients tested during the fever. Conclusion. We describe the largest cohort of PFAPA patients presented so far. We confirm that PFAPA may present with varied clinical manifestations and we show the limitations of the commonly used diagnostic criteria. Based on detailed analysis of this cohort, a consensus definition of PFAPA with better-defined criteria should be proposed.
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| 13. |
- Kaiser, Andreas-Marius, et al.
(författare)
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Comparison of extraction methods for per- and polyfluoroalkyl substances (PFAS) in human serum and placenta samples-insights into extractable organic fluorine (EOF)
- 2021
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Ingår i: Analytical and Bioanalytical Chemistry. - : Springer. - 1618-2642 .- 1618-2650. ; 413, s. 865-876
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Tidskriftsartikel (refereegranskat)abstract
- Since the detection of per- and polyfluoroalkyl substances (PFAS) in humans and different environmental media in the last two decades, this substance group has attracted a lot of attention as well as increasing concerns. The fluorine mass balance approach, by comparing the levels of targeted PFAS after conversion to fluorine equivalents with those of extractable organic fluorine (EOF), showed the presence of unidentified organofluorine in different environmental samples. Out of the thousands of PFAS in existence, only a very small fraction is included in routine analysis. In recent years, liquid chromatography coupled with tandem-mass spectrometry (LC-MS/MS) has demonstrated the ability to analytically cover a wide spectrum of PFAS. In contrast, conventional extraction methods developed 10 to 15 years ago were only evaluated for a limited number of PFAS. The aim of the present study was to evaluate the advantages and disadvantages of three different extraction methods, adapted from the literatures without further optimization (ion-pair liquid-liquid extraction, solid-phase extraction (SPE), using hydrophilic-lipophilic (HLB) or weak anion exchange (WAX) sorbents), for human biomonitoring of 61 PFAS in serum and placental tissue samples. In addition, levels of EOF were compared among these extraction methods via spiked samples. Results showed that performance, in terms of recovery, differed between the extraction methods for different PFAS; different extraction methods resulted in different EOF concentrations indicating that the choice of extraction method is important for target PFAS and EOF analysis. Results of maternal serum samples, analyzed in two different laboratories using two different extraction methods, showed an accordance of 107.6% (± 21.3); the detected perfluoroalkyl acids (PFAAs) in maternal and cord serum samples were in the range of 0.076 to 2.9 ng/mL.Graphical abstract.
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| 14. |
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| 15. |
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| 16. |
- Kaiser, Stefan, 1968, et al.
(författare)
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White Paper: Broadband Multi-Carrier Based Air Interface (version 1.4)
- 2002
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Ingår i: Proceedings 7th Wireless World Research Forum Workshop, Eindhoven, the Netherlands.
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Konferensbidrag (refereegranskat)abstract
- The future success of the mobile communications revolution strongly depends on increasing the data rate and quality of service (QoS) available to the mobile user. This will enable value added services, which are not possible with current state of the art mobile wireless radio systems. While an increase in data rate, and maybe to some extent also QoS, could be achieved by combining techniques in the form of multi mode terminals (e.g. UMTS and wireless LAN), this has the disadvantage that for each new scenario another mode has to be added. The combination may also not be suitable for the mobility requirements of wireless radio systems. This paper proposes using a broadband multi-carrier based air interface. It also includes a discussion of the enabling technologies for multi-carrier mobile systems and the technology trends for future research. The multi-carrier technology offers the desired high data rates for the 4G mobile environments and also has advantages for spectral efficiency and low-cost implementation.
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| 17. |
- Kaiser, Vera B, et al.
(författare)
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Homozygous loss-of-function variants in European cosmopolitan and isolate populations
- 2015
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Ingår i: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 24:19, s. 5464-5475
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Tidskriftsartikel (refereegranskat)abstract
- Homozygous Loss of Function (HLOF) variants provide a valuable window on gene function in humans, as well as an inventory of the human genes that are not essential for survival and reproduction. All humans carry at least a few HLOF variants, but the exact number of inactivated genes that can be tolerated is currently unknown - as are the phenotypic effects of losing function for most human genes. Here, we make use of 1,432 whole exome sequences from five European populations to expand the catalogue of known human HLOF mutations; after stringent filtering of variants in our dataset, we identify a total of 173 HLOF mutations, 76 (44%) of which have not been observed previously. We find that population isolates are particularly well suited to surveys of novel HLOF genes because individuals in such populations carry extensive runs of homozygosity, which we show are enriched for novel, rare HLOF variants. Further, we make use of extensive phenotypic data to show that most HLOFs, ascertained in population-based samples, appear to have little detectable effect on the phenotype. On the contrary, we document several genes directly implicated in disease that seem to tolerate HLOF variants. Overall HLOF genes are enriched for olfactory receptor function and are expressed in testes more often than expected, consistent with reduced purifying selection and incipient pseudogenisation.
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| 18. |
- Kubin, Markus, et al.
(författare)
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Soft x-ray absorption spectroscopy of metalloproteins and high-valent metal-complexes at room temperature using free-electron lasers
- 2017
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Ingår i: Structural Dynamics. - : AMER INST PHYSICS. - 2329-7778. ; 4:5
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Tidskriftsartikel (refereegranskat)abstract
- X-ray absorption spectroscopy at the L-edge of 3d transition metals provides unique information on the local metal charge and spin states by directly probing 3d-derived molecular orbitals through 2p-3d transitions. However, this soft x-ray technique has been rarely used at synchrotron facilities for mechanistic studies of metalloenzymes due to the difficulties of x-ray-induced sample damage and strong background signals from light elements that can dominate the low metal signal. Here, we combine femtosecond soft x-ray pulses from a free-electron laser with a novel x-ray fluorescence-yield spectrometer to overcome these difficulties. We present L-edge absorption spectra of inorganic high-valent Mn complexes (Mn similar to 6-15 mmol/l) with no visible effects of radiation damage. We also present the first L-edge absorption spectra of the oxygen evolving complex (Mn4CaO5) in Photosystem II (Mn < 1 mmol/l) at room temperature, measured under similar conditions. Our approach opens new ways to study metalloenzymes under functional conditions. (C) 2017 Author(s).
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| 19. |
- Martin, Jonathan, et al.
(författare)
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Analytical challenges hamper perfluoroalkyl research
- 2004
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 38:13, s. 248A-255A
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Tidskriftsartikel (refereegranskat)
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| 20. |
- Mattsson, Niklas, 1979, et al.
(författare)
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The Alzheimer's Association external quality control program for cerebrospinal fluid biomarkers.
- 2011
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Ingår i: Alzheimer's & dementia : the journal of the Alzheimer's Association. - : Wiley. - 1552-5279. ; 7:4
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Tidskriftsartikel (refereegranskat)abstract
- The cerebrospinal fluid (CSF) biomarkers amyloid β (Aβ)-42, total-tau (T-tau), and phosphorylated-tau (P-tau) demonstrate good diagnostic accuracy for Alzheimer's disease (AD). However, there are large variations in biomarker measurements between studies, and between and within laboratories. The Alzheimer's Association has initiated a global quality control program to estimate and monitor variability of measurements, quantify batch-to-batch assay variations, and identify sources of variability. In this article, we present the results from the first two rounds of the program.
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| 21. |
- Mitzner, Rolf, et al.
(författare)
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L-Edge X-ray Absorption Spectroscopy of Dilute Systems Relevant to Metalloproteins Using an X-ray Free-Electron Laser
- 2013
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Ingår i: The Journal of Physical Chemistry Letters. - : American Chemical Society (ACS). - 1948-7185. ; 4:21, s. 3641-3647
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Tidskriftsartikel (refereegranskat)abstract
- L-edge spectroscopy of 3d transition metals provides important electronic structure information and has been used in many fields. However, the use of this method for studying dilute aqueous systems, such as metalloenzymes, has not been prevalent because of severe radiation damage and the lack of suitable detection systems. Here we present spectra from a dilute Mn aqueous solution using a high-transmission zone-plate spectrometer at the Linac Coherent Light Source (LCLS). The spectrometer has been optimized for discriminating the Mn L-edge signal from the overwhelming 0 K-edge background that arises from water and protein itself, and the ultrashort LCLS X-ray pulses can outrun X-ray induced damage. We show that the deviations of the partial-fluorescence yield-detected spectra from the true absorption can be well modeled using the state-dependence of the fluorescence yield, and discuss implications for the application of our concept to biological samples.
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| 22. |
- Schleuning, Matthias, et al.
(författare)
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Specialization of Mutualistic Interaction Networks Decreases toward Tropical Latitudes
- 2012
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Ingår i: Current Biology. - : Elsevier BV. - 1879-0445 .- 0960-9822. ; 22:20, s. 1925-1931
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Tidskriftsartikel (refereegranskat)abstract
- Species-rich tropical communities are expected to be more specialized than their temperate counterparts [1-3]. Several studies have reported increasing biotic specialization toward the tropics [4-7], whereas others have not found latitudinal trends once accounting for sampling bias [8, 9] or differences in plant diversity [10, 11]. Thus, the direction of the latitudinal Specialization gradient remains contentious. With an unprecedented global data set, we investigated how biotic specialization between plants and animal pollinators or seed dispersers is associated with latitude, past and contemporary climate, and plant diversity. We show that in contrast to expectation, biotic specialization of mutualistic networks is significantly lower at tropical than at temperate latitudes. Specialization was more closely related to contemporary climate than to past climate stability, suggesting that current conditions have a stronger effect on biotic specialization than historical community stability. Biotic specialization decreased with increasing local and regional plant diversity. This suggests that high specialization of mutualistic interactions is a response of pollinators and seed dispersers to low plant diversity. This could explain why the latitudinal specialization gradient is reversed relative to the latitudinal diversity gradient. Low mutualistic network specialization in the tropics suggests higher tolerance against extinctions in tropical than in temperate communities.
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| 23. |
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| 24. |
- Unger, Jonas, 1978-, et al.
(författare)
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Next Generation Image Based Lighting using HDR Video
- 2011
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Ingår i: Proceeding SIGGRAPH '11 ACM SIGGRAPH 2011 Talks. - New York, NY, USA : ACM Special Interest Group on Computer Science Education. - 9781450309745 ; , s. article no 60-
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Konferensbidrag (refereegranskat)abstract
- We present an overview of our recently developed systems pipeline for capture, reconstruction, modeling and rendering of real world scenes based on state-of-the-art high dynamic range video (HDRV). The reconstructed scene representation allows for photo-realistic Image Based Lighting (IBL) in complex environments with strong spatial variations in the illumination. The pipeline comprises the following essential steps:1.) Capture - The scene capture is based on a 4MPixel global shutter HDRV camera with a dynamic range of more than 24 f-stops at 30 fps. The HDR output stream is stored as individual un-compressed frames for maximum flexibility. A scene is usually captured using a combination of panoramic light probe sequences [1], and sequences with a smaller field of view to maximize the resolution at regions of special interest in the scene. The panoramic sequences ensure full angular coverage at each position and guarantee that the information required for IBL is captured. The position and orientation of the camera is tracked during capture.2.) Scene recovery - Taking one or more HDRV sequences as input, a geometric proxy model of the scene is built using a semi-automatic approach. First, traditional computer vision algorithms such as structure from motion [2] and Manhattan world stereo [3] are used. If necessary, the recovered model is then modified using an interaction scheme based on visualizations of a volumetric representation of the scene radiance computed from the input HDRV sequence. The HDR nature of this volume also enables robust extraction of direct light sources and other high intensity regions in the scene.3.) Radiance processing - When the scene proxy geometry has been recovered, the radiance data captured in the HDRV sequences are re-projected onto the surfaces and the recovered light sources. Since most surface points have been imaged from a large number of directions, it is possible to reconstruct view dependent texture maps at the proxy geometries. These 4D data sets describe a combination of detailed geometry that has not been recovered and the radiance reflected from the underlying real surfaces. The view dependent textures are then processed and compactly stored in an adaptive data structure.4.) Rendering - Once the geometric and radiometric scene information has been recovered, it is possible to place virtual objects into the real scene and create photo-realistic renderings as illustrated above. The extracted light sources enable efficient sampling and rendering times that are fully comparable to that of traditional virtual computer graphics light sources. No previously described method is capable of capturing and reproducing the angular and spatial variation in the scene illumination in comparable detail.We believe that the rapid development of high quality HDRV systems will soon have a large impact on both computer vision and graphics. Following this trend, we are developing theory and algorithms for efficient processing HDRV sequences and using the abundance of radiance data that is going to be available.
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| 25. |
- Zeiske, Stefan, et al.
(författare)
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On the Impact of Cadmium Sulfide Layer Thickness on Kesterite Photodetector Performance
- 2023
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Ingår i: Advanced Photonics Research. - : Wiley-VCH Verlagsgesellschaft. - 2699-9293. ; 4:9
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Tidskriftsartikel (refereegranskat)abstract
- Kesterites are currently viewed as one of the most promising candidates for earth abundant and benign elements to substitute critical raw materials in photovoltaic technologies and may also be suitable for low-noise, room-temperature, self-powered photodetectors. However, while the impact of buffer layers on kesterite solar cell efficiency has been an active area of investigation, links between photodetector performance and intermediate layers are yet to be addressed. Herein, the impact of cadmium sulfide buffer layers on the performance of kesterite (Cu2ZnSnS4) photodetectors is probed. Specifically, the effect of buffer layer thickness on various photodetector performance metrices is clarified, including noise current, spectral responsivity, noise equivalent power, frequency response, and specific detectivity. Devices with a 100 nm cadmium sulfide layer perform the best, achieving a linear dynamic range of 180 dB and frequency responses in the range of tens of kHz. The key loss mechanisms are identified, and it is found that the photodetector performance to be primarily limited by shunt resistance-induced thermal noise and defect-induced nonradiative losses. Furthermore, we estimate the upper radiative limit of specific detectivity to be approximately 1019 Jones. Our results highlight the potential of kesterites to be used as an interesting earth abundant candidate for photodetection applications.
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