| 1. |
- Allentoft, Morten E., et al.
(författare)
-
100 ancient genomes show repeated population turnovers in Neolithic Denmark
- 2024
-
Ingår i: Nature. - 0028-0836 .- 1476-4687. ; 625, s. 329-337
-
Tidskriftsartikel (refereegranskat)abstract
- Major migration events in Holocene Eurasia have been characterized genetically at broad regional scales1–4. However, insights into the population dynamics in the contact zones are hampered by a lack of ancient genomic data sampled at high spatiotemporal resolution5–7. Here, to address this, we analysed shotgun-sequenced genomes from 100 skeletons spanning 7,300 years of the Mesolithic period, Neolithic period and Early Bronze Age in Denmark and integrated these with proxies for diet (13C and 15N content), mobility (87Sr/86Sr ratio) and vegetation cover (pollen). We observe that Danish Mesolithic individuals of the Maglemose, Kongemose and Ertebølle cultures form a distinct genetic cluster related to other Western European hunter-gatherers. Despite shifts in material culture they displayed genetic homogeneity from around 10,500 to 5,900 calibrated years before present, when Neolithic farmers with Anatolian-derived ancestry arrived. Although the Neolithic transition was delayed by more than a millennium relative to Central Europe, it was very abrupt and resulted in a population turnover with limited genetic contribution from local hunter-gatherers. The succeeding Neolithic population, associated with the Funnel Beaker culture, persisted for only about 1,000 years before immigrants with eastern Steppe-derived ancestry arrived. This second and equally rapid population replacement gave rise to the Single Grave culture with an ancestry profile more similar to present-day Danes. In our multiproxy dataset, these major demographic events are manifested as parallel shifts in genotype, phenotype, diet and land use.
|
|
| 2. |
- Allentoft, Morten E., et al.
(författare)
-
Population genomics of post-glacial western Eurasia
- 2024
-
Ingår i: Nature. - 0028-0836 .- 1476-4687. ; 625:7994, s. 301-311
-
Tidskriftsartikel (refereegranskat)abstract
- Western Eurasia witnessed several large-scale human migrations during the Holocene1–5. Here, to investigate the cross-continental effects of these migrations, we shotgun-sequenced 317 genomes—mainly from the Mesolithic and Neolithic periods—from across northern and western Eurasia. These were imputed alongside published data to obtain diploid genotypes from more than 1,600 ancient humans. Our analyses revealed a ‘great divide’ genomic boundary extending from the Black Sea to the Baltic. Mesolithic hunter-gatherers were highly genetically differentiated east and west of this zone, and the effect of the neolithization was equally disparate. Large-scale ancestry shifts occurred in the west as farming was introduced, including near-total replacement of hunter-gatherers in many areas, whereas no substantial ancestry shifts happened east of the zone during the same period. Similarly, relatedness decreased in the west from the Neolithic transition onwards, whereas, east of the Urals, relatedness remained high until around 4,000 bp, consistent with the persistence of localized groups of hunter-gatherers. The boundary dissolved when Yamnaya-related ancestry spread across western Eurasia around 5,000 bp, resulting in a second major turnover that reached most parts of Europe within a 1,000-year span. The genetic origin and fate of the Yamnaya have remained elusive, but we show that hunter-gatherers from the Middle Don region contributed ancestry to them. Yamnaya groups later admixed with individuals associated with the Globular Amphora culture before expanding into Europe. Similar turnovers occurred in western Siberia, where we report new genomic data from a ‘Neolithic steppe’ cline spanning the Siberian forest steppe to Lake Baikal. These prehistoric migrations had profound and lasting effects on the genetic diversity of Eurasian populations.
|
|
| 3. |
- Christensen, Mads G., et al.
(författare)
-
On Optimal Filter Designs for Fundamental Frequency Estimation
- 2008
-
Ingår i: IEEE Signal Processing Letters. - 1070-9908. ; 15, s. 745-748
-
Tidskriftsartikel (refereegranskat)abstract
- Recently, we proposed using Capon's minimum variance principle to find the fundamental frequency of a periodic waveform. The resulting estimator is formed such that it maximizes the output power of a bank of filters. We present an alternative optimal single filter design and then proceed to quantify the similarities and differences between the estimators using asymptotic analysis and Monte Carlo simulations. Our analysis shows that the single filter can be expressed in terms of the optimal filterbank and that the methods are asymptotically equivalent but generally different for finite length signals.
|
|
| 4. |
- Christensen, Mads, et al.
(författare)
-
Joint Fundamental Frequency and Order Estimation using Optimal Filtering
- 2009
-
Konferensbidrag (refereegranskat)abstract
- In this paper, two optimal filter designs for fundamental frequency estimation are presented with the first being based on a filterbank and the second on a single filter. We show that the two designs are related in a simple manner and result in the same residual when used for cancelling out the harmonics. We propose to use this residual for estimating the number of harmonics by combining a noise variance estimate with an order dependent penalty term. This leads to a joint estimator of the fundamental frequency and the order based on the same criterion. Via Monte Carlo simulations, the estimator is demonstrated to have good performance in terms of the percentage of correctly estimated orders.
|
|
| 5. |
- Ejlertsen, Bent, et al.
(författare)
-
Improved outcome from substituting methotrexate with epirubicin : results from a randomised comparison of CMF versus CEF in patients with primary breast cancer
- 2007
-
Ingår i: European Journal of Cancer. - : Elsevier BV. - 0959-8049 .- 1879-0852. ; 43:5, s. 877-884
-
Tidskriftsartikel (refereegranskat)abstract
- We compared the efficacy of CEF (cyclophosphamide, epirubicin, and fluorouracil) against CMF (cyclophosphamide, methotrexate, and fluorouracil) in moderate or high risk breast cancer patients. We randomly assigned 1224 patients with completely resected unilateral breast cancer to receive nine cycles of three-weekly intravenous CMF or CEF. Patients were encouraged to take part in a parallel trial comparing oral pamidronate 150 mg twice daily for 4 years versus control (data not shown). Substitution of methotrexate with epirubicin significantly reduced the unadjusted hazard for disease-free survival (DFS) by 16% (hazard ratio 0.84; 95% CI; 0.71-0.99) and for overall survival by 21% (hazard ratio 0.79; 95% CI; 0.66-0.94). The risk of secondary leukaemia and congestive heart failure was similar in the two groups. Overall CEF was superior over CMF in terms of DFS and OS in patients with operable breast cancer without subsequent increase in late toxicities.
|
|
| 6. |
- Gadegaard, Ane Riis, et al.
(författare)
-
Spectroscopy and picosecond dynamics of aqueous NO2
- 2014
-
Ingår i: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 141:6, s. 064310-
-
Tidskriftsartikel (refereegranskat)abstract
- We investigate the formation of aqueous nitrogen dioxide, NO2 formed through femtosecond photolysis of nitrate, NO3- ( aq) and nitromethane CH3NO2(aq). Common to the experiments is the observation of a strong induced absorption at 1610 +/- 10 cm(-1), assigned to the asymmetric stretch vibration in the ground state of NO2. This assignment is substantiated through isotope experiments substituting N-14 by N-15, experiments at different pH values, and by theoretical calculations and simulations of NO2-D2O clusters.
|
|
| 7. |
- Gunst, Jesper D., et al.
(författare)
-
Efficacy of the TMPRSS2 inhibitor camostat mesilate in patients hospitalized with Covid-19-a double-blind randomized controlled trial
- 2021
-
Ingår i: eClinicalMedicine. - : Elsevier. - 2589-5370. ; 35
-
Tidskriftsartikel (refereegranskat)abstract
- Background: The trans-membrane protease serine 2 (TMPRSS2) is essential for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) cell entry and infection. Efficacy and safety of TMPRSS2 inhibitors in patients with coronavirus disease 2019 (Covid-19) have not been evaluated in randomized trials.Methods: We conducted an investigator-initiated, double-blind, randomized, placebo-controlled multicenter trial in patients hospitalized with confirmed SARS-CoV-2 infection from April 4, to December 31, 2020. Within 48 h of admission, participants were randomly assigned in a 2:1 ratio to receive the TMPRSS2 inhibitor camostat mesilate 200 mg three times daily for 5 days or placebo. The primary outcome was time to discharge or clinical improvement measured as ≥2 points improvement on a 7-point ordinal scale. Other outcomes included 30-day mortality, safety and change in oropharyngeal viral load. ClinicalTrials.gov Identifier: NCT04321096. EudraCT Number: 2020-001,200-42.Findings: 137 patients were assigned to receive camostat mesilate and 68 to placebo. Median time to clinical improvement was 5 days (interquartile range [IQR], 3 to 7) in the camostat group and 5 days (IQR, 2 to 10) in the placebo group (P = 0·31). The hazard ratio for 30-day mortality in the camostat compared with the placebo group was 0·82 (95% confidence interval [CI], 0·24 to 2·79; P = 0·75). The frequency of adverse events was similar in the two groups. Median change in viral load from baseline to day 5 in the camostat group was -0·22 log10 copies/mL (p <0·05) and -0·82 log10 in the placebo group (P <0·05).Interpretation: Under this protocol, camostat mesilate treatment was not associated with increased adverse events during hospitalization for Covid-19 and did not affect time to clinical improvement, progression to ICU admission or mortality.
|
|
| 8. |
- Jensen, Jesper, et al.
(författare)
-
Computationally Efficient IAA-Based Estimation of the Fundamental Frequency
- 2012
-
Ingår i: Signal Processing Conference (EUSIPCO), 2012 Proceedings of the 20th European. - 2076-1465 .- 2219-5491. - 9781467310680 ; , s. 2163-2167
-
Konferensbidrag (refereegranskat)abstract
- Optimal linearly constrained minimum variance (LCMV) filtering methods have recently been applied to fundamental frequency estimation. Like many other fundamental frequency estimators, these methods are constructed using an estimate of the inverse data covariance matrix. The required matrix inverse is typically formed using the sample covariance matrix via data partitioning, although this is well-known to adversely affect the spectral resolution. In this paper, we propose a fast implementation of a novel optimal filtering method that utilizes the LCMV principle in conjunction with the iterative adaptive approach (IAA). The IAA formulation enables an accurate covariance matrix estimate from a single snapshot, i.e., without data partitioning, but the improvement comes at a notable computational cost. Exploiting the estimator's inherently low displacement rank of the necessary products of Toeplitz-like matrices, we form a computationally efficient implementation, reducing the required computational complexity with several orders of magnitude. The experimental results show that the performance of the proposed method is comparable or better than that of other competing methods in terms of spectral resolution.
|
|
| 9. |
- Quinson, Jonathan, et al.
(författare)
-
Surfactant-Free Colloidal Syntheses of Gold-Based Nanomaterials in Alkaline Water and Mono-alcohol Mixtures
- 2023
-
Ingår i: Chemistry of Materials. - : American Chemical Society (ACS). - 0897-4756 .- 1520-5002. ; 35:5, s. 2173-2190
-
Tidskriftsartikel (refereegranskat)abstract
- Gold nanoparticles (Au NPs) and gold-based nanomaterials combine unique properties relevant for medicine, imaging, optics, sensing, catalysis, and energy conversion. While the Turkevich-Frens and Brust-Schiffrin methods remain the state-of-the-art colloidal syntheses of Au NPs, there is a need for more sustainable and tractable synthetic strategies leading to new model systems. In particular, stabilizers are almost systematically used in colloidal syntheses, but they can be detrimental for fundamental and applied studies. Here, a surfactant-free synthesis of size-controlled colloidal Au NPs stable for months is achieved by the simple reduction of HAuCl4 at room temperature in alkaline solutions of low-viscosity mono-alcohols such as ethanol or methanol and water, without the need for any other additives. Palladium (Pd) and bimetallic AuxPdy NPs, nanocomposites and multimetallic samples, are also obtained and are readily active (electro)catalysts. The multiple benefits over the state-of-the-art syntheses that this simple synthesis bears for fundamental and applied research are highlighted.
|
|
| 10. |
|
|
| 11. |
- Abelein, Axel, et al.
(författare)
-
Formation of dynamic soluble surfactant-induced amyloid β peptide aggregation intermediates
- 2013
-
Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 288:32, s. 23518-23528
-
Tidskriftsartikel (refereegranskat)abstract
- Intermediate amyloidogenic states along the amyloid β peptide (Aβ) aggregation pathway have been shown to be linked to neurotoxicity. To shed more light on the different structures that may arise during Aβ aggregation, we here investigate surfactant-induced Aβ aggregation. This process leads to co-aggregates featuring a β-structure motif that is characteristic for mature amyloid-like structures. Surfactants induce secondary structure in Aβ in a concentration-dependent manner, from predominantly random coil at low surfactant concentration, via β-structure to the fully formed α-helical state at high surfactant concentration. The β-rich state is the most aggregation-prone as monitored by thioflavin T fluorescence. Small angle x-ray scattering reveals initial globular structures of surfactant-Aβ co-aggregated oligomers and formation of elongated fibrils during a slow aggregation process. Alongside this slow (minutes to hours time scale) fibrillation process, much faster dynamic exchange (k(ex) ∼1100 s(-1)) takes place between free and co-aggregate-bound peptide. The two hydrophobic segments of the peptide are directly involved in the chemical exchange and interact with the hydrophobic part of the co-aggregates. Our findings suggest a model for surfactant-induced aggregation where free peptide and surfactant initially co-aggregate to dynamic globular oligomers and eventually form elongated fibrils. When interacting with β-structure promoting substances, such as surfactants, Aβ is kinetically driven toward an aggregation-prone state.
|
|
| 12. |
- Abildgaard, Amanda B., et al.
(författare)
-
HSP70-binding motifs function as protein quality control degrons
- 2023
-
Ingår i: Cellular and Molecular Life Sciences (CMLS). - : Springer Science and Business Media LLC. - 1420-682X .- 1420-9071. ; 80:1
-
Tidskriftsartikel (refereegranskat)abstract
- Protein quality control (PQC) degrons are short protein segments that target misfolded proteins for proteasomal degradation, and thus protect cells against the accumulation of potentially toxic non-native proteins. Studies have shown that PQC degrons are hydrophobic and rarely contain negatively charged residues, features which are shared with chaperone-binding regions. Here we explore the notion that chaperone-binding regions may function as PQC degrons. When directly tested, we found that a canonical Hsp70-binding motif (the APPY peptide) functioned as a dose-dependent PQC degron both in yeast and in human cells. In yeast, Hsp70, Hsp110, Fes1, and the E3 Ubr1 target the APPY degron. Screening revealed that the sequence space within the chaperone-binding region of APPY that is compatible with degron function is vast. We find that the number of exposed Hsp70-binding sites in the yeast proteome correlates with a reduced protein abundance and half-life. Our results suggest that when protein folding fails, chaperone-binding sites may operate as PQC degrons, and that the sequence properties leading to PQC-linked degradation therefore overlap with those of chaperone binding.
|
|
| 13. |
- Agic, Heda, et al.
(författare)
-
Life through the 'Varanger ice ages' : microfossil record of late Neoproterozoic glacial-interglacial units from arctic Norway
- 2018
-
Ingår i: Geological Society of America <em>Abstracts with Programs</em>. - : Geological Society of America.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The late Neoproterozoic strata in Finnmark (Arctic Norway) provide a good sedimentary record of Neoproterozoic glaciations on the Baltica paleocontinent. The lower Vestertana Group exposed on the Digermulen Peninsula contains two glaciogenic units, the Smalfjord and Mortensnes formations. Chemostratigraphic correlation dated the Smalfjord diamictite to the Marinoan glaciation (650-635 Ma), yet its age was also proposed to be older, per correlation to glacial units in central and southern Scandinavia. The diamictites are bracketing shales and siltstones of the interglacial Nyborg Formation. Stratigraphic, paleontological, and sedimentological data are presented from the interglacial-glacial succession, investigated by the Digermulen Early Life Research Group. Palynological analysis yielded well-preserved organic-walled microfossils (OWM) from the Nyborg Fm., and from fine-grained diamictite matrix in the Mortensnes Fm. via a modified extraction method.The interglacial Nyborg Fm. hosts a moderate diversity assemblage of prokaryotic and eukaryotic OWM, as well as acanthomorphic acritarchs such as Ceratosphaeridium, ?Cavaspina, and a novel process-bearing form. Organically preserved, enigmatic multicellular eukaryotic fossils occur in the upper Nyborg Fm. The Mortensens glacial assemblage is less diverse and contains bacterial filaments, leiosphaerids, toroidal forms, and Micrhystridium-type minute acanthomorphs.The presence of Doushantuo-Pertatataka type acritarchs in the Nyborg Fm., and small acanthomorphs in the Mortensnes diamictite corroborate an early Ediacaran age for the interglacial-glacial succession on Digermulen. In addition to the trace fossil and body-fossil record of Ediacara-biota in the overlying Stáhpogieddi Formation, the microfossil biostratigraphy suggests Marinoan and Gaskiers glaciation equivalent ages of the Varanger glaciations in Finnmark. Protistan diversity in the succession declined through and following the glaciation, until late Ediacaran.
|
|
| 14. |
- Agić, Heda, 1989-, et al.
(författare)
-
Organically-preserved multicellular eukaryote from the early Ediacaran Nyborg Formation, Arctic Norway
- 2019
-
Ingår i: Scientific Reports. - : NATURE PUBLISHING GROUP. - 2045-2322. ; 9
-
Tidskriftsartikel (refereegranskat)abstract
- Eukaryotic multicellularity originated in the Mesoproterozoic Era and evolved multiple times since, yet early multicellular fossils are scarce until the terminal Neoproterozoic and often restricted to cases of exceptional preservation. Here we describe unusual organically-preserved fossils from mudrocks, that provide support for the presence of organisms with differentiated cells (potentially an epithelial layer) in the late Neoproterozoic. Cyathinema digermulense gen. et sp. nov. from the Nyborg Formation, Vestertana Group, Digermulen Peninsula in Arctic Norway, is a new carbonaceous organ-taxon which consists of stacked tubes with cup-shaped ends. It represents parts of a larger organism (multicellular eukaryote or a colony), likely with greater preservation potential than its other elements. Arrangement of open-ended tubes invites comparison with cells of an epithelial layer present in a variety of eukaryotic clades. This tissue may have benefitted the organism in: avoiding overgrowth, limiting fouling, reproduction, or water filtration. C. digermulense shares characteristics with extant and fossil groups including red algae and their fossils, demosponge larvae and putative sponge fossils, colonial protists, and nematophytes. Regardless of its precise affinity, C. digermulense was a complex and likely benthic marine eukaryote exhibiting cellular differentiation, and a rare occurrence of early multicellularity outside of Konservat-Lagerstatten.
|
|
| 15. |
- Agic, Heda, et al.
(författare)
-
Unusual organic-walled microfossil from the late Neoproterozoic Nyborg Formation, Digermulen Peninsula, Arctic Norway
- 2017
-
Ingår i: ISECT 2017.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The late Neoproterozoic Nyborg Formation is exposed in the Tanafjord area, Finnmark, Arctic Norway, on Digermulen and Varanger Peninsulas. The succession is composed of ~400 m of interbedded shales, siltstone and purple to grey sandstone, deposited between Neoproterozoic low latitude glacial deposits. The Nyborg Fm. lies on top of the Smalfjord diamictite, and is overlain by the Mortensnes diamictite (the latter was attributed to both Marinoan (650-635 Ma) and Gaskiers (579 Ma) glaciations) and the Ediacaran-Cambrian Stáhpogieddi Formation. Thus, the Nyborg Fm. represents late Neoproterozoic, probably the last Cryogenian interglacial interval. Presented material was collected in 2014 by members of Digermulen Early Life Research Group, from organic-rich, grey-green shales and siltstones of the Nyborg Mbr. D, uppermost Nyborg Fm. between Árasulluokta and Guvssájohka valleys. Organic-walled microfossils were extracted from shale via standard palynological acetolysis in hydrofluoric acid, and studied via light and scanning electron microscopy. Microfossils from the Nyborg Fm. include Synsphaeridium-type aggregated cells, unbranched bacterial filaments (Polythrichoides and Siphonophycus), sphaeromorph and envelope-bearing acritarchs (leiosphaerids, Stictosphaeridium, Simia), and previously unrecognized aggregated tubular microfossils. These taxa are long-ranging, but common in glacial-interglacial units worldwide, and thus broadly corroborate the Cryogenian age of the Nyborg sediments. The novel fossil, up to 300 μm in size, is a parenchymatous meshwork of interconnected organic-walled tubes that terminate in cup-shaped apices 4-11 µm in diameter. Irregular tube clusters are truncated both in macerates and in thin sections, suggesting post mortem transport. Elemental EDXS analysis indicates that extracted meshwork microfossils are predominantly composed of carbonaceous material and also associated with small amounts of titanium and vanadium. Considering the branching and adjoined body plan of carbonaceous fossil, it was likely multicellular and of eukaryotic affinity. As such, it may represent an important step in the evolution of complex multicellularity and morphological complexity several million years before the appearance of Ediacaran organisms.
|
|
| 16. |
- Aguinis, Herman, et al.
(författare)
-
The why, how, and what of public policy implications of tourism and hospitality research
- 2023
-
Ingår i: Tourism Management. - : Elsevier. - 0261-5177 .- 1879-3193. ; 97
-
Forskningsöversikt (refereegranskat)abstract
- We synthesized policy implications of tourism and hospitality research by reviewing 12,269 articles published in 10 leading journals from 2011 to 2021. The most common rationale for policies (i.e., the why) is market failure, while the most typical role of policies (i.e., the how) is to create incentives. In addition, policies are typically hybrid and include suggestions for formal and informal institutional setups (i.e., the what). Because our review revealed that only 114 articles (i.e., 0.93%) included the why, how, and what of actual policies, we offer a theory-based research agenda on policy-making focused on making tourism and hospitality more inclusive and focusing on evolutionary dynamics, providing an understanding of the impact of crises and contemporary solutions, focusing on resilience and institutional complexity, and addressing the actors and time dimension. Our results, combined with those of our suggested research directions, will benefit organizations and society and simultaneously enhance the perceived societal value-added, contributions, and stature of tourism and hospitality research. © 2023 The Authors
|
|
| 17. |
- Álvaro, J. Javier, et al.
(författare)
-
Ediacaran–Cambrian phosphorites from the western margins of Gondwana and Baltica
- 2016
-
Ingår i: Sedimentology. - : Wiley. - 0037-0746. ; 63:2, s. 350-377
-
Tidskriftsartikel (refereegranskat)abstract
- The late Ediacaran–mid Cambrian occurrence s of phosphorites in the wes-tern Mediterranean region (West Gondwana) and southern Sweden (north -west Baltica) are related to the poleward drift of West Gondwana and thenorthern drift of Baltica. As a result, these regions crossed subtropical andtemperate palaeolatitudes of the Southern Hemisphere, in which oceanicupwelling and high organic productivity were the probable sources of phos-phorus along their western margins. A parallel south-west/north-east migra-tion trend of evaporites and delayed, time transgressive phosphorites pointto distal upwelling environments associated with shallower arid conditions.Concentration of hardground-derived phosphate accumulations took placeby repeated alternations of low sedimentation rates and condensation,in situ early diagenetic and microbially mediated precipitation of amorphousand cryptocrystalline, carbonate-bearing francolite, winnowing and poly-phase reworking of previously phosphatized skeletons and hardground-derived clasts. Thicker phosphorites of economic importance display aspiculate sponge-thromboid consortium that points to a distinct benthiccommunity developed on suboxic, slope to basinal substrates. For mostphosphorite samples an up to ten-fold enrichment in rare earth elementconcentration relative to post-Archaean average Australian shale reflects sig-nificant incorporation of rare earth elements and yttrium after deposition.Considerable scavenging took place from anoxic pore waters, followingreductive dissolution of iron oxides as evidenced from the medium rareearth element enrichment in most samples. This contrasts with the rare pre-servation of primary sea water features, such as cerium depletion andyttrium enrichment, in phosphatized thrombolites from the shallower realms(for example, Montagne Noire). The data are consistent with phosphogenesisafter upwelling and transgression of nutrient-rich, suboxic–anoxic, ferrugi-nous waters over more oxygenated, rifting settings and inland portions of anevolving passive margin.
|
|
| 18. |
|
|
| 19. |
- Aznar, Marianne C., et al.
(författare)
-
A Monte Carlo study of the energy dependence of Al2O3:C crystals for real-time in vivo dosimetry in mammography
- 2005
-
Ingår i: Radiation Protection Dosimetry. - : Oxford University Press (OUP). - 0144-8420 .- 1742-3406. ; 114:Nos 1-3, s. 444-449
-
Tidskriftsartikel (refereegranskat)abstract
- In a previous experimental study, a novel method for in vivo dosimetry has been investigated, based on radioluminescence (RL) and optically stimulated luminescence (OSL). However, because of the large difference in atomic composition between the detector material and the breast tissue, relatively large energy dependence in low-energy X-ray beams can be expected. In the present work, the energy dependence of Al2O3:C crystals was modelled with the Monte Carlo code EGSnrc using three types of X-ray spectra. The results obtained (5.6-7.3%) agree with a previously determined experimental result (9%) within the combined standard uncertainty of the two methods. The influence of the size of the crystal on the energy dependence was investigated together with the effect of varying the thickness of the surrounding light-protective material. The results obtained indicate a minor effect owing to the thickness of the light-protective material, and a somewhat larger effect from reducing the diameter of the crystal. The outcome of this study can be used to improve the future design of the RL/OSL dosimetry system for use in mammography.
|
|
| 20. |
- Aznar, MC, et al.
(författare)
-
In vivo absorbed dose measurements in mammography using a new real-time luminescence technique
- 2005
-
Ingår i: British Journal of Radiology. - : British Institute of Radiology. - 1748-880X .- 0007-1285. ; 78:928, s. 328-334
-
Tidskriftsartikel (refereegranskat)abstract
- A dosimetry system based on radioluminescence (RL) and optically stimulated luminescence (OSL) from carbon doped aluminium oxide (Al2O3:C) crystals was developed for in vivo absorbed dose measurements in mammography. A small cylindrical crystal of Al2O3:C (diameter 0.48 mm and length 2 mm) was coupled to the end of a 1 mm diameter optical fibre cable. Owing to their small size and characteristic shape, these probes can be placed on the body surface in the field of view during the examination, without compromising the reading of the mammogram. Our new technique was tested with a mammography unit (Siemens Mammomat 3000) and screen-film technique over a range of clinically relevant X-ray energies. The results were compared with those obtained from an ionization chamber usually used for the determination of absorbed dose in mammography. The reproducibility of measurements was around 3% (1 standard deviation) at 4.5 mGy for both RL and OSL data. The dose response was found to be linear between 4.5 mGy and 30 mGy. The energy dependence of the system is around 18% between 23 kV and 35 kV. In vivo measurements were performed during three patient examinations. It was shown that entrance and exit doses could be measured. The presence of the small probes did not significantly interfere with the diagnostic quality of the images. Entrance doses estimated by RL/OSL results agreed within 3% with entrance surface dose values calculated from the ionization chamber measurements. These results indicate a considerable potential for use in routine control and in vivo dose measurements in mammography.
|
|
| 21. |
- Aznar, MC, et al.
(författare)
-
Real-time optical-fibre luminescence dosimetry for radiotherapy: physical characteristics and applications in photon beams
- 2004
-
Ingår i: Physics in Medicine and Biology. - : IOP Publishing. - 1361-6560 .- 0031-9155. ; 49:9, s. 1655-1669
-
Tidskriftsartikel (refereegranskat)abstract
- A new optical-fibre radiation dosimeter system, based on radioluminescence and optically stimulated luminescence from carbon-doped aluminium oxide, was developed and tested in clinical photon beams. This prototype offers several features, such as a small detector (1 x 1 x 2 mm), high sensitivity, real-time read-out and the ability to measure both dose rate and absorbed dose. The measurements describing reproducibility and output dependence on dose rate, field size and energy all had standard deviations smaller than 1%. The signal variation with the angle of incidence was smaller than 2% (1 SD). Measurements performed in clinical situations suggest the potential of using this real-time system for in vivo dosimetry in radiotherapy.
|
|
| 22. |
- Barbateskovic, Marija, et al.
(författare)
-
A new tool to assess Clinical Diversity In Meta-analyses (CDIM) of interventions
- 2021
-
Ingår i: Journal of Clinical Epidemiology. - : Elsevier BV. - 0895-4356 .- 1878-5921. ; 135, s. 29-41
-
Tidskriftsartikel (refereegranskat)abstract
- Objective: To develop and validate Clinical Diversity In Meta-analyses (CDIM), a new tool for assessing clinical diversity between trials in meta-analyses of interventions. Study design and setting: The development of CDIM was based on consensus work informed by empirical literature and expertise. We drafted the CDIM tool, refined it, and validated CDIM for interrater scale reliability and agreement in three groups. Results: CDIM measures clinical diversity on a scale that includes four domains with 11 items overall: setting (time of conduct/country development status/units type); population (age, sex, patient inclusion criteria/baseline disease severity, comorbidities); interventions (intervention intensity/strength/duration of intervention, timing, control intervention, cointerventions); and outcome (definition of outcome, timing of outcome assessment). The CDIM is completed in two steps: first two authors independently assess clinical diversity in the four domains. Second, after agreeing upon scores of individual items a consensus score is achieved. Interrater scale reliability and agreement ranged from moderate to almost perfect depending on the type of raters. Conclusion: CDIM is the first tool developed for assessing clinical diversity in meta-analyses of interventions. We found CDIM to be a reliable tool for assessing clinical diversity among trials in meta-analysis.
|
|
| 23. |
|
|
| 24. |
- Bignert, Anders, et al.
(författare)
-
Temporal trends of organochlorines in Northern Europe, 1967–1995. Relation to global fractionation, leakage from sediments and international measures
- 1998
-
Ingår i: Environmental Pollution. - 0269-7491 .- 1873-6424. ; 99:2, s. 177-198
-
Tidskriftsartikel (refereegranskat)abstract
- The time trend monitoring of organochlorine pollution was carried out in Sweden since the late 1960s. This report presents data on concentrations of DDT, PCB, HCHs and HCB in biota samples collected and analysed annually. All the matrices and compounds studied show a significant decrease over time. The data cover severely polluted Swedish marine and fresh water in southern Sweden as well as locally unpolluted waters in remote northern Arctic regions of Sweden. A total of 13 time series representing different locations and species are presented for the different pollutants. The period studied covers the time when pollution was serious as well as the time of recovery. All monitoring activities were carried out at the same laboratories over the entire study period, which means that comparability over time is good in the sets of data presented. The various time trends show a convincing agreement with trends and annual change over time, although the concentrations differ between the species and locations investigated, the highest concentrations being in the south. Since the annual changes are normally similar regardless of locations and species, spatial variations in concentrations remain over time, although concentrations are lower today. The onset of changes in concentrations over time can be related to international measures or other circumstances that lowered releases into the environment. Similarities in the annual changes, as well as the time when changes began, are discussed with respect to suggested hypotheses on the fate of the investigated organochlorines. It was not possible to verify that the oxygenation of anoxic sediments mobilised old pollution in Baltic sediments. Neither was it possible to conclude that eutrophication has caused a measurable effect on the rate and timing of the decreases. Finally, long-range transport to Arctic regions seems to be due more to a one step transport than to the ‘Grass-hopper’ effect. The comprehensive database used, clearly shows how important it is to have datasets big enough to describe between-year variation before attempting to evaluate the time trend. In addition, if between-year variation is not known, it is then also difficult to evaluate spatial variation on the basis of single year observations.
|
|
| 25. |
|
|
| 26. |
|
|
| 27. |
- Budd, Graham, et al.
(författare)
-
The origin of the animals and a ‘Savannah’ hypothesis for early bilaterian evolution
- 2017
-
Ingår i: Biological Reviews. - : Wiley. - 1464-7931 .- 1469-185X. ; 92:1, s. 446-473
-
Tidskriftsartikel (refereegranskat)abstract
- The earliest evolution of the animals remains a taxing biological problem, as all extant clades are highly derived and the fossil record is not usually considered to be helpful. The rise of the bilaterian animals recorded in the fossil record, commonly known as the ‘Cambrian explosion’, is one of the most significant moments in evolutionary history, and was an event that transformed first marine and then terrestrial environments. We review the phylogeny of early animals and other opisthokonts, and the affinities of the earliest large complex fossils, the so-called ‘Ediacaran’ taxa. We conclude, based on a variety of lines of evidence, that their affinities most likely lie in various stem groups to large metazoan groupings; a new grouping, the Apoikozoa, is erected to encompass Metazoa and Choanoflagellata. The earliest reasonable fossil evidence for total-group bilaterians comes from undisputed complex trace fossils that are younger than about 560 Ma, and these diversify greatly as the Ediacaran–Cambrian boundary is crossed a few million years later. It is generally considered that as the bilaterians diversified after this time, their burrowing behaviour destroyed the cyanobacterial mat-dominated substrates that the enigmatic Ediacaran taxa were associated with, the so-called ‘Cambrian substrate revolution’, leading to the loss of almost all Ediacara-aspect diversity in the Cambrian. Why, though, did the energetically expensive and functionally complex burrowing mode of life so typical of later bilaterians arise? Here we propose a much more positive relationship between late-Ediacaran ecologies and the rise of the bilaterians, with the largely static Ediacaran taxa acting as points of concentration of organic matter both above and below the sediment surface. The breaking of the uniformity of organic carbon availability would have signalled a decisive shift away from the essentially static and monotonous earlier Ediacaran world into the dynamic and burrowing world of the Cambrian. The Ediacaran biota thus played an enabling role in bilaterian evolution similar to that proposed for the Savannah environment for human evolution and bipedality. Rather than being obliterated by the rise of the bilaterians, the subtle remnants of Ediacara-style taxa within the Cambrian suggest that they remained significant components of Phanerozoic communities, even though at some point their enabling role for bilaterian evolution was presumably taken over by bilaterians or other metazoans. Bilaterian evolution was thus an essentially benthic event that only later impacted the planktonic environment and the style of organic export to the sea floor.
|
|
| 28. |
- Bugge Harder, Christoffer, et al.
(författare)
-
Successional trophic complexity and biogeographical structure of eukaryotic communities in waterworks' rapid sand filters
- 2019
-
Ingår i: FEMS Microbiology Ecology. - : Oxford University Press (OUP). - 0168-6496 .- 1574-6941. ; 95:11
-
Tidskriftsartikel (refereegranskat)abstract
- As groundwater-fed waterworks clean their raw inlet water with sand filters, a variety of pro-and eukaryotic microbial communities develop on these filters. While several studies have targeted the prokaryotic sand filter communities, little is known about the eukaryotic communities, despite the obvious need for knowledge of microorganisms that get in contact with human drinking water. With a new general eukaryotic primer set (18S, V1-V3 region), we performed FLX-454 sequencing of material from 21 waterworks' sand filters varying in age (3-40 years) and geographical location on a 250 km east-west axis in Denmark, and put the data in context of their previously published prokaryotic communities. We find that filters vary highly in trophic complexity depending on age, from simple systems with bacteria and protozoa (3-6 years) to complex, mature systems with nematodes, rotifers and turbellarians as apex predators (40 years). Unlike the bacterial communities, the eukaryotic communities display a clear distance-decay relationship that predominates over environmental variations, indicating that the underlying aquifers feeding the filters harbor distinct eukaryotic communities with limited dispersal in between. Our findings have implications for waterworks' filter management, and offer a window down to the largely unexplored eukaryotic microbiology of groundwater aquifers.
|
|
| 29. |
- Christensen, Mads, et al.
(författare)
-
Joint Fundamental Frequency and Order Estimation using Optimal Filtering
- 2011
-
Ingår i: Eurasip Journal on Advances in Signal Processing. - : Springer Science and Business Media LLC. - 1687-6172 .- 1687-6180. ; 2011:june
-
Tidskriftsartikel (refereegranskat)abstract
- Abstract in UndeterminedIn this paper, the problem of jointly estimating the number of harmonics and the fundamental frequency of periodic signals is considered. We show how this problem can be solved using a number of methods that either are or can be interpreted as filtering methods in combination with a statistical model selection criterion. The methods in question are the classical comb filtering method, a maximum likelihood method, and some filtering methods based on optimal filtering that have recently been proposed, while the model selection criterion is derived herein from the maximum a posteriori principle. The asymptotic properties of the optimal filtering methods are analyzed and an order-recursive efficient implementation is derived. Finally, the estimators have been compared in computer simulations that show that the optimal filtering methods perform well under various conditions. It has previously been demonstrated that the optimal filtering methods perform extremely well with respect to fundamental frequency estimation under adverse conditions, and this fact, combined with the new results on model order estimation and efficient implementation, suggests that these methods form an appealing alternative to classical methods for analyzing multi-pitch signals
|
|
| 30. |
- Christensen, Mads, et al.
(författare)
-
Sinusoidal Order Estimation using Angles between Subspaces
- 2009
-
Ingår i: Eurasip Journal on Advances in Signal Processing. - : Springer Science and Business Media LLC. - 1687-6172 .- 1687-6180.
-
Tidskriftsartikel (refereegranskat)abstract
- Abstract in UndeterminedWe consider the problem of determining the order of a parametric model from a noisy signal based on the geometry of the space. More specifically, we do this using the nontrivial angles between the candidate signal subspace model and the noise subspace. The proposed principle is closely related to the subspace orthogonality property known from the MUSIC algorithm, and we study its properties and compare it to other related measures. For the problem of estimating the number of complex sinusoids in white noise, a computationally efficient implementation exists, and this problem is therefore considered in detail. In computer simulations, we compare the proposed method to various well-known methods for order estimation. These show that the proposed method outperforms the other previously published subspace methods and that it is more robust to the noise being colored than the previously published methods. Copyright (C) 2009 Mads Graesboll Christensen et al.
|
|
| 31. |
|
|
| 32. |
|
|
| 33. |
|
|
| 34. |
|
|
| 35. |
- Ebbestad, Jan Ove R., 1967-, et al.
(författare)
-
Biostratigraphy and palaeontology of the lower Cambrian Duolbagáisá Formation on the Digermulen Peninsula, Arctic Norway
- 2018
-
Ingår i: International Conference on Arctic Margins.
-
Konferensbidrag (refereegranskat)abstract
- The lower Cambrian sequence on the Digermulen Peninsula (Finnmark, Arctic Norway) is the northernmost extension of the Cambrian deposits along the Caledonian front. It is exceedingly thick compared to cratonal successions typical of most of Baltica. The Duolbagáisá Formation represents the youngest lower Cambrian unit on the peninsula with the first trilobite-bearing strata, a plethora of trace fossils including diverse arthropod traces and Plagiogmus arcuatus, and abundant and wellpreserved organic walled microfossils (OWM). Extensive field work by the Digermulen Early Life Research Group allows for the first time a detailed appreciation of the age and faunal composition of the unit. The lower member is ~250 m thick with thin-bedded siltstone, sandstone and mudstone. A single unidentifiable holmiid thorax region occurs alongside arthropod trace fossils. OWM indicate the S. ornata-F. membranacea Zone. The upper member is ~390 m thick and consist of several upward shallowing parasequences with fine-grained sandstone, siltstone and mudstone followed by thick mature quartzite. The trace fossil Syringomorpha occurs throughout the upper member and Cruziana and Rusophycus are especially abundant in the upper parts. The first identifiable olenellid trilobites occur in a thick mudstone/siltstone interval at the middle of the member, along with an elliptocephalid trilobite and other arthropods. Abundant OWM indicate the H. dissimilare-S. ciliosa Zone with the higher levels belonging to the Volkovia-Liepaina Zone. The entire sequence thus span the Cambrian Series 2, stages 3–5.
|
|
| 36. |
- Ebbestad, Jan Ove R., et al.
(författare)
-
Distribution and correlation of Sabellidites cambriensis (Annelida?) in the basal Cambrian on Baltica
- 2021
-
Ingår i: Geological Magazine. - Cambridge : Cambridge University Press (CUP). - 0016-7568 .- 1469-5081. ; 159:7, s. 1262-1283
-
Tidskriftsartikel (refereegranskat)abstract
- Sabellidites cambriensis is a tubular non-mineralized metazoan that appears as compressed ribbon-shaped imprints with transverse wrinkling, thick walls and an even tube diameter of up to 3 mm. The distribution of Sabellidites is investigated in three Ediacaran–Cambrian sections on the Digermulen Peninsula in Arctic Norway, spanning the Manndrapselva Member of the Stáhpogieddi Formation and the lower member of the Breidvika Formation. Here, the Ediacaran–Cambrian boundary is located in the lower part of the upper parasequence (third cycle) of the Manndrapselva Member. Specimens of Sabellidites are rare but consistently present close to the lowest level of Treptichnus pedum and upsection, whereas the taxon is common and abundant in the lower part of the lower member of the Breidvika Formation, with an upper record at c. 55 m above the base. The range is comparable with that of the GSSP section in Newfoundland, Canada, establishing Sabellidites as an index fossil for the lowermost Cambrian. In the Manndrapselva Member, Sabellidites co-occurs with the acritarch Granomarginata, indicative of the lowermost Cambrian Granomarginata Zone, whereas in the Breidvika Formation it co-occurs with Asteridium. Sabellidites is widely distributed in Baltica, through the Rovnian and Lontovan regional stages but confined to the Fortunian global stage. In its lower range, Sabellidites is associated with a Treptichnus pedum trace fossil association and a depauperate leiosphaerid acritarch assemblage, followed by a Granomarginata assemblage. In its upper range, Sabellidites co-occurs with acritarchs of the Asteridium–Comasphaeridium Zone and the tubular foraminiferan Platysolenites. In Baltica, Sabellidites is a useful index fossil.
|
|
| 37. |
|
|
| 38. |
- Ebbestad, Jan Ove R., 1967-, et al.
(författare)
-
Holmiid trilobites from the lower Cambrian of the Digermulen Peninsula, Arctic Norway
- 2017
-
Ingår i: 6th International Conference on Trilobites and their Relatives. Tallinn, Estonia, 7-10 July 2017. - Tallinn : Libris Est OU. - 9789949818617
-
Konferensbidrag (refereegranskat)abstract
- Lower Cambrian holmiid olenelloids are used for biozonation of lower Cambrian (Series 2) strata in Baltoscandia. About a dozen species have been named since the description of Holmia kjerulfi (Linnarsson, 1868), but except for the classical area in Mjøsa, Norway, the species traditionally occur in small numbers, are variably preserved, occur at one or a few localities only and usually with only one taxon present. Definitions of the biozones are therefore still problematic. One level in the lower Cambrian Duolbasgáissá Formation of the Digermulen Peninsula, Arctic Norway, has yielded more than 50 new specimens of holmiids, preliminarily assigned to Elliptocephala n. sp. and Kjerulfia n. sp. Acritarchs indicate the Heliosphaeridium dissimilare–Skagia ciliosa acritarch Zone which corresponds to the traditional Holmia kjerulfi Assemblage Zone. Elliptocephala n. sp. is known from about a dozen specimens. It is characterized by very long palpebral lobes, a parallel-sided glabella, a short anterior glabellar lobe and short genal spines. A node is developed on the occipital ring. Semi-complete specimens show up to 10 thoracic segments, but the full number of thoracic segments and the pygidium is unknown. The slightly older E. lundgreni (Moberg, 1892), known from the Schmidtiellus mickwitzi Zone of southern Sweden, differs in the proportions of the glabella, the length of the palpebral lobes and definition of the cephalic border. Both H. mobergi and H. sulcata from Sweden show similarities to Elliptocephala n. sp. in the weakly developed lateral border with an effaced anterior border furrow. Nikolaisen & Henningsmoen (1987) described Kjerulfia lata Kiær, 1917 from two fragmentary specimens from this locality in Digermulen. More than 20 new specimens from this site shows that the species differs from Kjerulfia lata from the type area in southern Norway in proportions and features of the glabella, the width of the genal field and the possession of a stout and high spine on the occipital ring, and it is tentatively assigned to Kjerulfia n. sp. The material from the Digermulen Peninsula adds to the diversity of the Baltoscandian holmiids and is tightly constrained stratigraphically.
|
|
| 39. |
- Ebbestad, Jan Ove R., 1967-, et al.
(författare)
-
Stratigraphy of the Ediacaran and basal Cambrian of the Digermulen Peninsula, Northern Norway
- 2015
-
Ingår i: Geological Society of America Abstracts with Programs, vol 47.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The succession of the Digermulen Peninsula in Finnmark, northern Norway, is the only fossiliferous site inScandinavia with sedimentation across the Ediacaran–Cambrian transition without a significant hiatus. Geologicalinvestigations started in the 1930’s, but the Peninsula was first mapped in the 60’s. Ediacara-type fossils werefirst discovered in the late 80’s but recent discoveries will establish the Digermulen Peninsula as one of the mostsignificant Ediacaran sites in northern Europe. The parautochthonous strata are exposed in the Tanafjord areaalong the coast and in valleys on the east side of the Peninsula. The beds dip slightly to the west with the strikefollowing the coastline (ca. 045°). The Ediacaran succession is close to 1000 m thick and dominantly siliciclastic.It starts with interglacial sediments of the Nyborg Formation (tentatively the earliest Ediacaran), overlying astacked succession of diamictites of the Cryogenian Smalfjord Formation. After a hiatus follows the glaciogenicdiamictites of the Mortensnes Formation (~60 m thick), which is commonly seen to represent the ~582 Ma-oldGaskiers glaciation. Upwards, the contact to the overlying Stáhpogiedde Formation is not exposed locally, but hasbeen shown to represent a hiatus followed by transitional fluvial to marine sediments of the Lillevannet Member.Ediacaran-type fossils appear in the succeeding Innerelva Member. This is a two-cycle deepening upwardssuccession of laminated mudstone with intercalated sand bodies showing load structures. Preliminary microfossilssamples of the Member have so far proven almost barren, making dating more challenging. The basal part of thesucceeding Manndraperelva Member consists of three cycles; first a succession of reddish sandstone followed bytwo coarsening-upward cycles. Each starts with mudstone and fine sandstone and terminates in cross-beddedsandstone. The Ediacaran–Cambrian boundary is located within the third cycle, identified by the trace fossilTreptichnus pedum and associated trilobed trace fossils.The Digermulen Early Life Research Group has since2011 made significant new finds, and focused fieldwork aims to resolve tighter age constraints, provenance of thesediments and the range and diversity of the extended Ediacaran biota.
|
|
| 40. |
|
|
| 41. |
- Ellinghaus, David, et al.
(författare)
-
Analysis of five chronic inflammatory diseases identifies 27 new associations and highlights disease-specific patterns at shared loci
- 2016
-
Ingår i: Nature Genetics. - New York, USA : Nature Publishing Group. - 1061-4036 .- 1546-1718. ; 48:5, s. 510-518
-
Tidskriftsartikel (refereegranskat)abstract
- We simultaneously investigated the genetic landscape of ankylosing spondylitis, Crohn's disease, psoriasis, primary sclerosing cholangitis and ulcerative colitis to investigate pleiotropy and the relationship between these clinically related diseases. Using high-density genotype data from more than 86,000 individuals of European ancestry, we identified 244 independent multidisease signals, including 27 new genome-wide significant susceptibility loci and 3 unreported shared risk loci. Complex pleiotropy was supported when contrasting multidisease signals with expression data sets from human, rat and mouse together with epigenetic and expressed enhancer profiles. The comorbidities among the five immune diseases were best explained by biological pleiotropy rather than heterogeneity (a subgroup of cases genetically identical to those with another disease, possibly owing to diagnostic misclassification, molecular subtypes or excessive comorbidity). In particular, the strong comorbidity between primary sclerosing cholangitis and inflammatory bowel disease is likely the result of a unique disease, which is genetically distinct from classical inflammatory bowel disease phenotypes.
|
|
| 42. |
- Frisvad, Jeppe Revall, et al.
(författare)
-
Survey of Models for Acquiring the Optical Properties of Translucent Materials
- 2020
-
Ingår i: Computer graphics forum (Print). - : Wiley. - 0167-7055 .- 1467-8659. ; 39, s. 729-755
-
Tidskriftsartikel (refereegranskat)abstract
- The outset of realistic rendering is a desire to reproduce the appearance of the real world. Rendering techniques therefore operate at a scale corresponding to the size of objects that we observe with our naked eyes. At the same time, rendering techniques must be able to deal with objects of nearly arbitrary shapes and materials. These requirements lead to techniques that oftentimes leave the task of setting the optical properties of the materials to the user. Matching the appearance of real objects by manual adjustment of optical properties is however nearly impossible. We can render objects with a plausible appearance in this way but cannot compare the appearance of a manufactured item to that of its digital twin. This is especially true in the case of translucent objects, where we need more than a goniometric measurement of the optical properties. In this survey, we provide an overview of forward and inverse models for acquiring the optical properties of translucent materials. We map out the efforts in graphics research in this area and describe techniques available in related fields. Our objective is to provide a better understanding of the tools currently available for appearance specification when it comes to digital representations of real translucent objects.
|
|
| 43. |
- Fu, Jinglin, et al.
(författare)
-
Survey of bidirectional transmittance distribution function measurement facilities by multilateral scale comparisons
- 2024
-
Ingår i: Metrologia. - : Institute of Physics. - 0026-1394 .- 1681-7575. ; 61:3
-
Tidskriftsartikel (refereegranskat)abstract
- In recent years, a growing demand for the capability of performing accurate measurements of the bidirectional transmittance distribution function (BTDF) has been observed in industry, research and development, and aerospace applications. However, there exists no calibration and measurement capabilities-entry for BTDF in the database of the Bureau International des Poids et Mesures and to date no BTDF comparison has been conducted between different national metrology institutes (NMIs) or designated institutes (DIs). As a first step to a possible future key comparison and to test the existing capabilities of determining this measurand, two interlaboratory comparisons were performed. In comparison one, five samples of three different types of optical transmissive diffusers were measured by five NMIs and one DI. By specific sample choice, the focus for this study lay more on orientation-dependent scatter properties. In comparison two, where one NMI, one DI, one university, and three industrial partners investigated their measurement capabilities, the dependence on the orientation was not assessed, but two additional samples of the same material and different thickness were measured. Results of the two comparisons are presented, giving a good overview of existing experimental solutions, and showing specific sample-related problems to be solved for improved future BTDF measurements.
|
|
| 44. |
|
|
| 45. |
- Have Beck, Iben, et al.
(författare)
-
Association Between Prenatal and Early Postnatal Exposure to Perfluoroalkyl Substances and IQ Score in 7-Year-Old Children From the Odense Child Cohort
- 2023
-
Ingår i: American Journal of Epidemiology. - 0002-9262. ; 192:9, s. 1522-1535
-
Tidskriftsartikel (refereegranskat)abstract
- Perfluoroalkyl substances (PFAS) are persistent chemicals capable of crossing the placenta and passing into breast milk. Evidence suggests that PFAS exposure may affect brain development. We investigated whether prenatal or early postnatal PFAS exposure was associated with intelligence quotient (IQ) scores in schoolchildren from the Odense Child Cohort (Denmark, 2010–2020). We assessed concentrations of perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorohexane sulfonic acid (PFHxS), perfluorononanoic acid (PFNA), and perfluorodecanoic acid (PFDA) in maternal serum collected during the first trimester of pregnancy and in child serum at age 18 months. At 7 years of age, children completed an abbreviated version of the Wechsler Intelligence Scale for Children, Fifth Edition, from which Full Scale Intelligence Quotient (FSIQ) and Verbal Comprehension Index scores were estimated. In multiple linear regression analyses conducted among 967 mother-child pairs, a doubling in maternal PFOS and PFNA concentrations was associated with a lower FSIQ score, while no significant associations were observed for PFOA, PFHxS, or PFDA. PFAS concentrations at age 18 months and duration of breastfeeding were strongly correlated, and even in structural equation models it was not possible to differentiate between the opposite effects of PFAS exposure and duration of breastfeeding on FSIQ. PFAS exposure is ubiquitous; therefore, an association with even a small reduction in IQ is of public health concern.
|
|
| 46. |
|
|
| 47. |
- Holm, Niels R, et al.
(författare)
-
OCT or Angiography Guidance for PCI in Complex Bifurcation Lesions.
- 2023
-
Ingår i: The New England journal of medicine. - 1533-4406. ; 389:16, s. 1477-1487
-
Tidskriftsartikel (refereegranskat)abstract
- Imaging-guided percutaneous coronary intervention (PCI) is associated with better clinical outcomes than angiography-guided PCI. Whether routine optical coherence tomography (OCT) guidance in PCI of lesions involving coronary-artery branch points (bifurcations) improves clinical outcomes as compared with angiographic guidance is uncertain.We conducted a multicenter, randomized, open-label trial at 38 centers in Europe. Patients with a clinical indication for PCI and a complex bifurcation lesion identified by means of coronary angiography were randomly assigned in a 1:1 ratio to OCT-guided PCI or angiography-guided PCI. The primary end point was a composite of major adverse cardiac events (MACE), defined as death from a cardiac cause, target-lesion myocardial infarction, or ischemia-driven target-lesion revascularization at a median follow-up of 2 years.We assigned 1201 patients to OCT-guided PCI (600 patients) or angiography-guided PCI (601 patients). A total of 111 patients (18.5%) in the OCT-guided PCI group and 116 (19.3%) in the angiography-guided PCI group had a bifurcation lesion involving the left main coronary artery. At 2 years, a primary end-point event had occurred in 59 patients (10.1%) in the OCT-guided PCI group and in 83 patients (14.1%) in the angiography-guided PCI group (hazard ratio, 0.70; 95% confidence interval, 0.50 to 0.98; P=0.035). Procedure-related complications occurred in 41 patients (6.8%) in the OCT-guided PCI group and 34 patients (5.7%) in the angiography-guided PCI group.Among patients with complex coronary-artery bifurcation lesions, OCT-guided PCI was associated with a lower incidence of MACE at 2 years than angiography-guided PCI. (Funded by Abbott Vascular and others; OCTOBER ClinicalTrials.gov number, NCT03171311.).
|
|
| 48. |
|
|
| 49. |
- Hu, Lan
(författare)
-
Molten carbonate fuel cells for electrolysis
- 2016
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The molten carbonate fuel cell has evolved to current megawatt-scale commercial power plants. When using the fuel cell for electrolysis, it provides a promising option for producing fuel gases such as hydrogen and syngas. The cell can thereby operate reversibly as a dual energy converter for electricity generation and fuel gas production. The so-called reversible molten carbonate fuel cell will probably increase the usefulness of the system and improve the economic benefits.This work has investigated the performance and durability of the cell in electrolysis and reversible operations. A lower polarization loss is found for the electrolysis cell than for the fuel cell, mainly due to the NiO electrode performing better in the MCEC. The stability of the cell in long-term tests evidences the feasibility of the MCEC and the RMCFC using a conventional fuel cell set-up, at least in lab-scale.This study elucidates the electrode kinetics of hydrogen production and oxygen production. The experimentally obtained partial pressure dependencies for hydrogen production are high, and they do not reasonably satisfy the reverse pathways of the hydrogen oxidation mechanisms. The reverse process of an oxygen reduction mechanism in fuel cell operation is found to suitably describe oxygen production in the MCEC.To evaluate the effect of the reverse water-gas shift reaction and the influence of the gas phase mass transport on the porous Ni electrode in the electrolysis cell, a mathematical model is applied in this study. When the humidified inlet gas compositions enter the current collector the decrease of the shift reaction rate increases the electrode performance. The model well describes the polarization behavior of the Ni electrode when the inlet gases have low contents of reactants. The experimental data and modeling results are consistent in that carbon dioxide has a stronger effect on the gas phase mass transport than other components, i.e. water and hydrogen.
|
|
| 50. |
- Hviid Malling, Gritt Marie, et al.
(författare)
-
Taking fertility for granted – a qualitative exploration of fertility awareness among young, childless men in Denmark and Sweden
- 2020
-
Ingår i: Human Fertility. - : Taylor & Francis Group. - 1464-7273 .- 1742-8149. ; , s. 1-12
-
Tidskriftsartikel (refereegranskat)abstract
- Most previous studies about fertility knowledge and attitudes among men have been based on quantitative methods using questionnaires with fixed-choice response options. The aims of this qualitative study were to explore childless young men’s reflections on fertility and infertility through semi-structured interviews. Danish (n = 17) and Swedish (n = 12) young childless men aged between 20 and 30 years in their last year of education were interviewed. Data were analysed using qualitative content analysis. Few informants had considered their own fertility, and most were positive towards fertility treatment. The young men had inadequate knowledge about factors that can potentially impair male and female fertility. On average, the young men each mentioned three different factors they believed influence male and female fertility: (i) health behaviour; (ii) factors beyond personal control; and (iii) age. None mentioned sexual transmitted infections (STIs) but most appeared aware of the effect of increasing age on fertility. The results of this study highlight the need for educational strategies to improve young men’s knowledge about fertility and the factors that influence it, particularly about the potential adverse effect of STIs on fertility.
|
|
