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| 2. |
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| 3. |
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| 4. |
- Ruilope, LM, et al.
(författare)
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Design and Baseline Characteristics of the Finerenone in Reducing Cardiovascular Mortality and Morbidity in Diabetic Kidney Disease Trial
- 2019
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Ingår i: American journal of nephrology. - : S. Karger AG. - 1421-9670 .- 0250-8095. ; 50:5, s. 345-356
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Tidskriftsartikel (refereegranskat)abstract
- <b><i>Background:</i></b> Among people with diabetes, those with kidney disease have exceptionally high rates of cardiovascular (CV) morbidity and mortality and progression of their underlying kidney disease. Finerenone is a novel, nonsteroidal, selective mineralocorticoid receptor antagonist that has shown to reduce albuminuria in type 2 diabetes (T2D) patients with chronic kidney disease (CKD) while revealing only a low risk of hyperkalemia. However, the effect of finerenone on CV and renal outcomes has not yet been investigated in long-term trials. <b><i>Patients and</i></b> <b><i>Methods:</i></b> The Finerenone in Reducing CV Mortality and Morbidity in Diabetic Kidney Disease (FIGARO-DKD) trial aims to assess the efficacy and safety of finerenone compared to placebo at reducing clinically important CV and renal outcomes in T2D patients with CKD. FIGARO-DKD is a randomized, double-blind, placebo-controlled, parallel-group, event-driven trial running in 47 countries with an expected duration of approximately 6 years. FIGARO-DKD randomized 7,437 patients with an estimated glomerular filtration rate ≥25 mL/min/1.73 m<sup>2</sup> and albuminuria (urinary albumin-to-creatinine ratio ≥30 to ≤5,000 mg/g). The study has at least 90% power to detect a 20% reduction in the risk of the primary outcome (overall two-sided significance level α = 0.05), the composite of time to first occurrence of CV death, nonfatal myocardial infarction, nonfatal stroke, or hospitalization for heart failure. <b><i>Conclusions:</i></b> FIGARO-DKD will determine whether an optimally treated cohort of T2D patients with CKD at high risk of CV and renal events will experience cardiorenal benefits with the addition of finerenone to their treatment regimen. Trial Registration: EudraCT number: 2015-000950-39; ClinicalTrials.gov identifier: NCT02545049.
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| 5. |
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| 6. |
- Markevych, I., et al.
(författare)
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Residential greenspace and lung function decline over 20 years in a prospective cohort: The ECRHS study
- 2023
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Ingår i: Environment International. - : Elsevier. - 0160-4120 .- 1873-6750. ; 178
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Tidskriftsartikel (refereegranskat)abstract
- Background: The few studies that have examined associations between greenspace and lung function in adulthood have yielded conflicting results and none have examined whether the rate of lung function decline is affected.Objective: We explored the association between residential greenspace and change in lung function over 20 years in 5559 adults from 22 centers in 11 countries participating in the population-based, international European Community Respiratory Health Survey.Methods: Forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC) were measured by spirometry when participants were approximately 35 (1990-1994), 44 (1999-2003), and 55 (2010-2014) years old. Greenness was assessed as the mean Normalized Difference Vegetation Index (NDVI) in 500 m, 300 m, and 100 m circular buffers around the residential addresses at the time of lung function measurement. Green spaces were defined as the presence of agricultural, natural, or urban green spaces in a circular 300 m buffer. Associations of these greenspace parameters with the rate of lung function change were assessed using adjusted linear mixed effects regression models with random intercepts for subjects nested within centers. Sensitivity analyses considered air pollution exposures.Results: A 0.2-increase (average interquartile range) in NDVI in the 500 m buffer was consistently associated with a faster decline in FVC (-1.25 mL/year [95% confidence interval:-2.18 to-0.33]). These associations were especially pronounced in females and those living in areas with low PM10 levels. We found no consistent asso-ciations with FEV1 and the FEV1/FVC ratio. Residing near forests or urban green spaces was associated with a faster decline in FEV1, while agricultural land and forests were related to a greater decline in FVC. Conclusions: More residential greenspace was not associated with better lung function in middle-aged European adults. Instead, we observed slight but consistent declines in lung function parameters. The potentially detri-mental association requires verification in future studies.
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| 7. |
- Duong, T. C., et al.
(författare)
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A hierarchical computational thermodynamic and kinetic approach to discontinuous precipitation in the U-Nb system
- 2015
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Ingår i: PTM 2015 - Proceedings of the International Conference on Solid-Solid Phase Transformations in Inorganic Materials 2015. - : International Conference on Solid-Solid Phase Transformations in Inorganic Materials. - 9780692437360 ; , s. 887-894
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Konferensbidrag (refereegranskat)abstract
- U-Nb alloys decompose via discontinuous precipitation (DP) over a broad range of aging conditions, adversely affecting their properties. The growth kinetics, lamellar spacing, and Nb partitioning have been measured, but the thermodynamic and kinetic factors underlying these specific transformation characteristics and reaction paths, vis-a-vis the monotectoid reaction, are not fully resolved. In this work, a hierarchical computational thermodynamic and kinetic approach was carried out to investigate DP. The hierarchical approach started with density-functional theory (DFT) investigations of ground-state formation energies of bcc-based U-Nb alloys. The estimated energetic data was then utilized as an imposed first-principles-based constraint to improve the consistency of the CALPHAD thermodynamic and, subsequently, kinetic assessments of U-Nb. Phasefield simulations were then carried out to study DP's microstructure evolution using the assessed CALPHAD thermodynamic and kinetic representations. Good agreement with experiments on different physical/length scales was achieved, which validates the present theoretical contributions to a better understanding of DP in U-Nb alloys.
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| 8. |
- Amaral, A. F. S., et al.
(författare)
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Changes in IgE sensitization and total IgE levels over 20 years of follow-up
- 2016
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Ingår i: Journal of Allergy and Clinical Immunology. - : Elsevier BV. - 0091-6749 .- 1097-6825. ; 137:6
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Tidskriftsartikel (refereegranskat)abstract
- Background Cross-sectional studies have reported a lower prevalence of sensitization in older adults, but few longitudinal studies have examined whether this is an aging or a year-of-birth cohort effect. Objective We sought to assess changes in sensitization and total IgE levels in a cohort of European adults as they aged over a 20-year period. Methods Levels of serum specific IgE to common aeroallergens (house dust mite, cat, and grass) and total IgE levels were measured in 3206 adults from 25 centers in the European Community Respiratory Health Survey on 3 occasions over 20 years. Changes in sensitization and total IgE levels were analyzed by using regression analysis corrected for potential differences in laboratory equipment and by using inverse sampling probability weights to account for nonresponse. Results Over the 20-year follow-up, the prevalence of sensitization to at least 1 of the 3 allergens decreased from 29.4% to 24.8% (-4.6%; 95% CI, -7.0% to -2.1%). The prevalence of sensitization to house dust mite (-4.3%; 95% CI, -6.0% to -2.6%) and cat (-2.1%; 95% CI, -3.6% to -0.7%) decreased more than sensitization to grass (-0.6%; 95% CI, -2.5% to 1.3%). Age-specific prevalence of sensitization to house dust mite and cat did not differ between year-of-birth cohorts, but sensitization to grass was most prevalent in the most recent ones. Overall, total IgE levels decreased significantly (geometric mean ratio, 0.63; 95% CI, 0.58-0.68) at all ages in all year-of-birth cohorts. Conclusion Aging was associated with lower levels of sensitization, especially to house dust mite and cat, after the age of 20 years. © 2015 The Authors. Published by Elsevier, Inc. on behalf ofthe American Academy of Allergy, Asthma&Immunology. This is an open access article under the CC BY license.
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| 9. |
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| 10. |
- Landa, A., et al.
(författare)
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Ab initio study of advanced metallic nuclear fuels for fast breeder reactors
- 2012
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Ingår i: Actinides And Nuclear Energy Materials. - : Materials Research Society. - 9781605114217 ; , s. 67-78
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Konferensbidrag (refereegranskat)abstract
- Density-functional formalism is applied to study the ground state properties of γ-U-Zr and γ-U-Mo solid solutions. Calculated heats of formation are compared with CALPHAD assessments. We discuss how the heat of formation in both alloys correlates with the charge transfer between the alloy components. The decomposition curves for γ-based U-Zr and U-Mo solid solutions are derived from Ising-type Monte Carlo simulations. We explore the idea of stabilization of the γ-UZr2 compound against the α-Zr (hcp) structure due to increase of Zr d-band occupancy by the addition of U to Zr. We discuss how the specific behavior of the electronic density of states in the vicinity of the Fermi level promotes the stabilization of the U2Mo compound. The mechanism of possible Am redistribution in the U-Zr and U-Mo fuels is also discussed.
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| 11. |
- Landa, A., et al.
(författare)
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Density-functional study of bcc Pu-U, Pu-Np, Pu-Am, and Pu-Cm alloys
- 2011
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Ingår i: Journal of Nuclear Materials. - : Elsevier BV. - 0022-3115 .- 1873-4820. ; 408:1, s. 61-66
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Tidskriftsartikel (refereegranskat)abstract
- Density-functional theory previously used to describe phase equilibria in the gamma-Pu-U-Zr alloys [A. Landa, P. Soderlind, PEA. Turchi, L. Vitos, A. Ruban, J. Nucl. Mater. 385 (2009) 68; A. Landa, P. Soderlind, PEA. Turchi, L. Vitos, A. Ruban, J. Nucl. Mater. 393 (2009) 141], is extended to study ground-state properties of the gamma-Pu-Np, gamma-Pu-Am, and gamma-Pu-Cm solid solutions. Calculated heats of formation are compared with CALPHAD assessments where possible. We discuss how the heat of formation correlates with the charge transfer between the alloy components.
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| 12. |
- Landa, A., et al.
(författare)
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Density-functional study of Zr-based actinide alloys
- 2009
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Ingår i: Journal of Nuclear Materials. - : Elsevier BV. - 0022-3115 .- 1873-4820. ; 385:1, s. 68-71
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Tidskriftsartikel (refereegranskat)abstract
- Density-functional formalism is applied to study the phase equilibria in the U-Zr system. The obtained ground-state properties of the gamma (bcc) and delta (02) phases are in good agreement with experimental data. The decomposition curve for the gamma-based U-Zr solutions is calculated. We argue that stabilization of the delta-UZr2 phase relative to the alpha-Zr (hcp) structure is due to an increase of the Zr d-band occupancy that occurs when U is alloyed with Zr.
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| 13. |
- Landa, A., et al.
(författare)
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Density-functional study of Zr-based actinide alloys : 2. U-Pu-Zr system
- 2009
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Ingår i: Journal of Nuclear Materials. - : Elsevier BV. - 0022-3115 .- 1873-4820. ; 393:1, s. 141-145
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Tidskriftsartikel (refereegranskat)abstract
- Density-functional theory, previously used to describe phase equilibria in the U-Zr alloys [A. Landa, P. Soderlind, P.E.A. Turchi, L. Vitos, A. Ruban, J. Nucl. Mater. 385 (2009) 68[, is applied to study ground-state properties of the bcc U-Pu-Zr solid solutions. Calculated heats of formation of the Pu-U and Pu-Zr alloys are in a good agreement with CALPHAD assessments. We found that account for spin-orbit coupling is important for successful description of Pu-containing alloys.
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| 14. |
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| 15. |
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| 16. |
- Landa, A. I., et al.
(författare)
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Phase stability of Li(Mn100-xCox)O-2 oxides : an ab initio study
- 2002
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Ingår i: Solid State Ionics. - 0167-2738 .- 1872-7689. ; 149:04-mar, s. 209-215
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Tidskriftsartikel (refereegranskat)abstract
- The full charge density exact muffin-tin orbitals method has been used to study the stability of lithium manganese oxides exhibiting different crystallographic forms. Calculations have been performed in various crystallographic phases of LiMnO2 for the ferromagnetic and antiferromagnetic spin configurations on Mn sublattice, as well as for the state with local moment disorder. For the ordered LiMnO2 compound, the experimentally observed antiferromagnetic orthorhombic ground state structure was reproduced. The effect of doping of the Mn sites by Co was considered with the primary aim to predict the stabilization of the layered structure.
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| 17. |
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| 18. |
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| 19. |
- Söderlind, P., et al.
(författare)
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Prediction of the new efficient permanent magnet SmCoNiFe3
- 2017
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Ingår i: Physical Review B. - : AMER PHYSICAL SOC. - 2469-9950 .- 2469-9969. ; 96:10
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Tidskriftsartikel (refereegranskat)abstract
- We propose a new efficient permanent magnet, SmCoNiFe3, which is a development of the well-known SmCo5 prototype. More modern neodymium magnets of the Nd-Fe-B type have an advantage over SmCo5 because of their greater maximum energy products due to their iron-rich stoichiometry. Our new magnet, however, removes most of this disadvantage of SmCo5 while preserving its superior high-temperature efficiency over the neodymium magnets. We show by means of first-principles electronic-structure calculations that SmCoNiFe3 has very favorable magnetic properties and could therefore potentially replace SmCo5 or Nd-Fe-B types in various applications.
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| 20. |
- Angerbjörn, Anders, et al.
(författare)
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Carnivore conservation in practice : replicatedmanagement actions on a large spatial scale
- 2013
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Ingår i: Journal of Applied Ecology. - : Wiley. - 0021-8901 .- 1365-2664. ; 50:1, s. 59-67
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Tidskriftsartikel (refereegranskat)abstract
- More than a quarter of the world’s carnivores are threatened, often due to multiple andcomplex causes. Considerable research efforts are devoted to resolving the mechanisms behindthese threats in order to provide a basis for relevant conservation actions. However, evenwhen the underlying mechanisms are known, specific actions aimed at direct support for carnivoresare difficult to implement and evaluate at efficient spatial and temporal scales.2. We report on a 30-year inventory of the critically endangered Fennoscandian arctic foxVulpes lagopus L., including yearly surveys of 600 fox dens covering 21 000 km2. These surveysshowed that the population was close to extinction in 2000, with 40–60 adult animalsleft. However, the population subsequently showed a fourfold increase in size.3. During this time period, conservation actions through supplementary feeding and predatorremoval were implemented in several regions across Scandinavia, encompassing 79% of thearea. To evaluate these actions, we examined the effect of supplemental winter feeding andred fox control applied at different intensities in 10 regions. A path analysis indicated that47% of the explained variation in population productivity could be attributed to lemmingabundance, whereas winter feeding had a 29% effect and red fox control a 20% effect.4. This confirms that arctic foxes are highly dependent on lemming population fluctuationsbut also shows that red foxes severely impact the viability of arctic foxes. This study also highlightsthe importance of implementing conservation actions on extensive spatial and temporalscales, with geographically dispersed actions to scientifically evaluate the effects. We note thatpopulation recovery was only seen in regions with a high intensity of management actions.5. Synthesis and applications. The present study demonstrates that carnivore populationdeclines may be reversed through extensive actions that target specific threats. Fennoscandianarctic fox is still endangered, due to low population connectivity and expected climate impactson the distribution and dynamics of lemmings and red foxes. Climate warming is expected tocontribute to both more irregular lemming dynamics and red fox appearance in tundra areas;however, the effects of climate change can be mitigated through intensive managementactions such as supplemental feeding and red fox control.
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| 21. |
- Bakker, D. C. E., et al.
(författare)
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A multi-decade record of high-quality fCO(2) data in version 3 of the Surface Ocean CO2 Atlas (SOCAT)
- 2016
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Ingår i: Earth System Science Data. - : Copernicus GmbH. - 1866-3508 .- 1866-3516. ; 8:2, s. 383-413
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Tidskriftsartikel (refereegranskat)abstract
- The Surface Ocean CO2 Atlas (SOCAT) is a synthesis of quality-controlled fCO(2) (fugacity of carbon dioxide) values for the global surface oceans and coastal seas with regular updates. Version 3 of SOCAT has 14.7 million fCO(2) values from 3646 data sets covering the years 1957 to 2014. This latest version has an additional 4.6 million fCO(2) values relative to version 2 and extends the record from 2011 to 2014. Version 3 also significantly increases the data availability for 2005 to 2013. SOCAT has an average of approximately 1.2 million surface water fCO(2) values per year for the years 2006 to 2012. Quality and documentation of the data has improved. A new feature is the data set quality control (QC) flag of E for data from alternative sensors and platforms. The accuracy of surface water fCO(2) has been defined for all data set QC flags. Automated range checking has been carried out for all data sets during their upload into SOCAT. The upgrade of the interactive Data Set Viewer (previously known as the Cruise Data Viewer) allows better interrogation of the SOCAT data collection and rapid creation of high-quality figures for scientific presentations. Automated data upload has been launched for version 4 and will enable more frequent SOCAT releases in the future. High-profile scientific applications of SOCAT include quantification of the ocean sink for atmospheric carbon dioxide and its long-term variation, detection of ocean acidification, as well as evaluation of coupled-climate and ocean-only biogeochemical models. Users of SOCAT data products are urged to acknowledge the contribution of data providers, as stated in the SOCAT Fair Data Use Statement. This ESSD (Earth System Science Data) "living data" publication documents the methods and data sets used for the assembly of this new version of the SOCAT data collection and compares these with those used for earlier versions of the data collection (Pfeil et al., 2013; Sabine et al., 2013; Bakker et al., 2014).Individual data set files, included in the synthesis product, can be downloaded here: doi:10.1594/PANGAEA.849770. The gridded products are available here: doi: 10.3334/CDIAC/OTG.SOCAT_V3_GRID.
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| 22. |
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| 23. |
- Dalén, Love, et al.
(författare)
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Population structure in a critically endangered arctic fox population : does genetics matter?
- 2006
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Ingår i: Molecular Ecology. - 0962-1083 .- 1365-294X. ; 15:10, s. 2809-2819
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Tidskriftsartikel (refereegranskat)abstract
- The arctic fox (Alopex lagopus) in Scandinavia is classified as critically endangered after having gone through a severe decline in population size in the beginning of the 20th century, from which it has failed to recover despite more than 65 years of protection. Arctic foxes have a high dispersal rate and often disperse over long distances, suggesting that there was probably little population differentiation within Scandinavia prior to the bottleneck. It is, however, possible that the recent decline in population size has led to a decrease in dispersal and an increase in population fragmentation. To examine this, we used 10 microsatellite loci to analyse genetic variation in 150 arctic foxes from Scandinavia and Russia. The results showed that the arctic fox in Scandinavia presently is subdivided into four populations, and that the Kola Peninsula and northwest Russia together form a large fifth population. Current dispersal between the populations seemed to be very low, but genetic variation within them was relatively high. This and the relative F-ST values among the populations are consistent with a model of recent fragmentation within Scandinavia. Since the amount of genetic variation is high within the populations, but the populations are small and isolated, demographic stochasticity seems to pose a higher threat to the populations' persistence than inbreeding depression and low genetic variation.
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| 24. |
- Duong, Thien C., et al.
(författare)
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Revisiting thermodynamics and kinetic diffusivities of uranium-niobium with Bayesian uncertainty analysis
- 2016
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Ingår i: CALPHAD-COMPUTER COUPLING OF PHASE DIAGRAMS AND THERMOCHEMISTRY. - : Elsevier. - 0364-5916. ; 55, s. 219-230
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Tidskriftsartikel (refereegranskat)abstract
- In this work, thermodynamic and kinetic diffusivities of uranium-niobium (U-Nb) are re-assessed by means of the CALPHAD (CALculation of PHAse Diagram) methodology. In order to improve the consistency and reliability of the assessments, first-principles calculations are coupled with CALPHAD. In particular, heats of formation of gamma-U-Nb are estimated and verified using various density-functional theory (DFT) approaches. These thermochemistry data are then used as constraints to guide the thermodynamic optimization process in such a way that the mutual-consistency between first-principles calculations and CALPHAD assessment is satisfactory. In addition, long-term aging experiments are conducted in order to generate new phase equilibria data at the gamma(2)/alpha + gamma(2) boundary. These data are meant to verify the thermodynamic model. Assessment results are generally in good agreement with experiments and previous calculations, without showing the artifacts that were observed in previous modeling. The mutual-consistent thermodynamic description is then used to evaluate atomic mobility and diffusivity of gamma-U-Nb. Finally, Bayesian analysis is conducted to evaluate the uncertainty of the thermodynamic model and its impact on the system's phase stability.
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| 25. |
- Emanuelson, Anna, et al.
(författare)
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A comparative study of ordinary and mineralised Portland cement clinker from two different production units Part II: Characteristics of the calcium silicates
- 2003
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Ingår i: Cement and Concrete Research. - 0008-8846. ; 33:10, s. 1623-1630
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Tidskriftsartikel (refereegranskat)abstract
- Portland cement clinkers from two production units were investigated in order to determine the effects of mineralisation on alite and belite; Plant 1: ordinary clinker (P1) and clinker mineralised with CaF2 + CaSO4 (P1M); Plant 2: ordinary clinker (P2) and two clinkers mineralised with CaF2 + CaSO4 (P2m, P2m'). The polymorphism of alite was studied using synchrotron X-ray powder diffraction (XRD), wavelength 1.5227 Angstrom, and electron diffraction (ED) in a transmission electron microscope. The substitutions of minor elements in alite and belite were determined using electron microprobe analysis. Clinkers P1 and P1m both contained apparent rhombohedral alite (XRD) with an incommensurately modulated structure (ED), while clinkers P2, P2m, and P2m' all contained monoclinic alite (XRD). The addition of mineralisers in the process caused increased content of fluoride in alite and increased substitution of Si(4+) by Al(3+) and S(6+) in both calcium silicates. The latter effect was most pronounced in clinker P1m due to its high molar SO3 to alkali oxide ratio (R = 2.18). The improved hydraulic activity of P1m compared to P1 was caused by substitutions rather than a change in symmetry. The decreased hydraulic activity of P2m and P2m' compared to P2 was explained by the high levels of fluorine, which had a retarding effect on the hydration. (C) 2003 Elsevier Ltd. All rights reserved.
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| 26. |
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| 27. |
- Flexeder, Claudia, et al.
(författare)
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Second-hand smoke exposure in adulthood and lower respiratory health during 20 year follow up in the European Community Respiratory Health Survey
- 2019
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Ingår i: Respiratory Research. - : BioMed Central. - 1465-9921 .- 1465-993X. ; 20
-
Tidskriftsartikel (refereegranskat)abstract
- Early life exposure to tobacco smoke has been extensively studied but the role of second-hand smoke (SHS) for new-onset respiratory symptoms and lung function decline in adulthood has not been widely investigated in longitudinal studies. Our aim is to investigate the associations of exposure to SHS in adults with respiratory symptoms, respiratory conditions and lung function over 20 years. We used information from 3011 adults from 26 centres in 12 countries who participated in the European Community Respiratory Health Surveys I-III and were never or former smokers at all three surveys. Associations of SHS exposure with respiratory health (asthma symptom score, asthma, chronic bronchitis, COPD) were analysed using generalised linear mixed-effects models adjusted for confounding factors (including sex, age, smoking status, socioeconomic status and allergic sensitisation). Linear mixed-effects models with additional adjustment for height were used to assess the relationships between SHS exposure and lung function levels and decline. Reported exposure to SHS decreased in all 26 study centres over time. The prevalence of SHS exposure was 38.7% at baseline (1990-1994) and 7.1% after the 20-year follow-up (2008-2011). On average 2.4% of the study participants were not exposed at the first, but were exposed at the third examination. An increase in SHS exposure over time was associated with doctor-diagnosed asthma (odds ratio (OR): 2.7; 95% confidence interval (95%-CI): 1.2-5.9), chronic bronchitis (OR: 4.8; 95%-CI: 1.6-15.0), asthma symptom score (count ratio (CR): 1.9; 95%-CI: 1.2-2.9) and dyspnoea (OR: 2.7; 95%-CI: 1.1-6.7) compared to never exposed to SHS. Associations between increase in SHS exposure and incidence of COPD (OR: 2.0; 95%-CI: 0.6-6.0) or lung function (beta: - 49 ml; 95%-CI: -132, 35 for FEV1 and beta: - 62 ml; 95%-CI: -165, 40 for FVC) were not apparent. Exposure to second-hand smoke may lead to respiratory symptoms, but this is not accompanied by lung function changes.
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| 28. |
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| 29. |
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| 30. |
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| 31. |
- Landa, A., et al.
(författare)
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Ab initio calculations of elastic constants of the bcc V-Nb system at high pressures
- 2006
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Ingår i: Journal of Physics and Chemistry of Solids. - : Elsevier BV. - 0022-3697 .- 1879-2553. ; 67:10-sep, s. 2056-2064
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Tidskriftsartikel (refereegranskat)abstract
- First-principles total energy calculation based on the exact muffin-tin orbital and full-potential linear muffin-tin orbital methods were used to calculate the equation of state and shear elastic constants of bcc V, Nb, and the V95Nb05 disordered alloy as a function of pressure up to 6 Mbar. We found a mechanical instability in C-44 and a corresponding softening in C at pressures similar to 2 Mbar for V. Both shear elastic constants show softening at pressures similar to 0.5 Mbar for Nb. Substitution of 5 at% of V with Nb removes the instability of V with respect to trigonal distortions in the vicinity of 2 Mbar pressure, but still leaves the softening of C-44 in this pressure region. We argue that the pressure-induced shear instability (softening) of V (Nb) originates from the electronic system and can be explained by a combination of the Fermi surface nesting, electronic topological transition, and band Jahn-Teller effect.
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| 32. |
- Landa, A., et al.
(författare)
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Alloying-driven phase stability in group-VB transition metals under compression
- 2010
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 82:14, s. 144114-
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Tidskriftsartikel (refereegranskat)abstract
- The change in phase stability of group-VB (V, Nb, and Ta) transition metals due to pressure and alloying is explored by means of first-principles electronic-structure calculations. It is shown that under compression stabilization or destabilization of the ground-state body-centered-cubic (bcc) phase of the metal is mainly dictated by the band-structure energy that correlates well with the position of the Kohn anomaly in the transverse-acoustic-phonon mode. The predicted position of the Kohn anomaly in V, Nb, and Ta is found to be in a good agreement with data from the inelastic x-ray or neutron-scattering measurements. In the case of alloying the change in phase stability is defined by the interplay between the band-structure and Madelung energies. We show that band-structure effects determine phase stability when a particular group-VB metal is alloyed with its nearest neighbors within the same d-transition series: the neighbor with less and more d electrons destabilize and stabilize the bcc phase, respectively. When V is alloyed with neighbors of a higher (4d- or 5d-) transition series, both electrostatic Madelung and band-structure energies stabilize the body-centered-cubic phase. The opposite effect (destabilization) happens when Nb or Ta is alloyed with neighbors of the 3d-transition series.
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| 33. |
- Landa, A., et al.
(författare)
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Fermi surface nesting and pre-martensitic softening in V and Nb at high pressures
- 2006
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Ingår i: Journal of Physics. - : IOP Publishing. - 0953-8984 .- 1361-648X. ; 18:22, s. 5079-5085
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Tidskriftsartikel (refereegranskat)abstract
- First-principles total-energy calculations were performed for the trigonal shear elastic constant (C-44) of body-centred cubic (bcc) V and Nb. A mechanical instability in C44 is found for V at pressures of similar to 2 Mbar which also shows a softening in Nb at pressures of similar to 0.5 Mbar. We argue that the pressure-induced shear instability (softening) of V (Nb) is due to the intra-band nesting of the Fermi surface.
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| 34. |
- Landa, A., et al.
(författare)
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First-principles phase diagram of the Ce-Th system
- 2004
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 70:22
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Tidskriftsartikel (refereegranskat)abstract
- Ab initio total energy calculations based on the exact muffin-tin orbitals (EMTO) theory are used to determine the high pressure and low-temperature phase diagram of Ce and Th metals as well as the Ce43Th57 disordered alloy. The compositional disorder for the alloy is treated in the framework of the coherent potential approximation. The equation of state for Ce, Th, and Ce43Th57 has been calculated up to 1 Mbar in good comparison with experimental data: upon compression the Ce-Th system undergoes crystallographic phase transformation from a fcc to a body-centered-tetragonal structure and the transition pressure increases with Th content in the alloy.
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| 35. |
- Landa, A., et al.
(författare)
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Monte Carlo simulations of the stability of delta-Pu
- 2003
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Ingår i: Journal of Physics. - : IOP Publishing. - 0953-8984 .- 1361-648X. ; 15:24, s. L371-L376
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Tidskriftsartikel (refereegranskat)abstract
- The transition temperature (T-c) for delta-Pu has been calculated for the first time. A Monte Carlo method is employed for this purpose and the effective cluster interactions are obtained from first-principles calculations incorporated with the Connolly-Williams and generalized perturbation methods. It is found that at T-c similar to 548 K, delta-Pu undergoes transformation from a disordered magnetic state to a structure with an anti ferromagnetic spin alignment that is mechanically unstable with respect to tetragonal distortion. The calculated transition temperature is in good agreement with the temperature measured at the gamma --> delta transition (593 K).
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| 36. |
- Landa, A., et al.
(författare)
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Stability in bcc Transition Metals : Madelung and Band-Energy Effects due to Alloying
- 2009
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 103:23
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Tidskriftsartikel (refereegranskat)abstract
- The phase stability of group VB (V, Nb, and Ta) transition metals is explored by first-principles electronic-structure calculations. Alloying with a small amount of a neighboring metal can either stabilize or destabilize the body-centered-cubic phase relative to low-symmetry rhombohedral phases. We show that band-structure effects determine phase stability when a particular group VB metal is alloyed with its nearest neighbors within the same d-transition series. In this case, the neighbor with less (to the left) and more (to the right) d electrons destabilize and stabilize bcc, respectively. When alloying with neighbors of higher d-transition series, electrostatic Madelung energy dominates and stabilizes the body-centered-cubic phase. This surprising prediction invalidates current understanding of simple d-electron bonding that dictates high-symmetry cubic and hexagonal phases.
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| 37. |
- Landa-Cánovas, A, et al.
(författare)
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On the Non-Stoichiometry in Rutile-Type »SbVO4
- 1995
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Ingår i: Journal of Solid State Chemistry. - : Elsevier BV. - 0022-4596. ; 116:2, s. 369-377
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Tidskriftsartikel (refereegranskat)abstract
- Heating equimolar mixtures of Sb2O3 and V2O5 at 800 degrees C in flowing gas with varying O-2/N-2 ratios produces a continuous nonstoichiometric series of rutile type, i.e., Sb(0.9)V(0.9+x)square(0.2-x)O(4), 0 < x < 0.2, and varying amounts of alpha-Sb2O4. Oxidized Sb(0.9)V(0.9)square(0.2)O(4), a = 4.63, c = 3.03 Angstrom (X ray powder data, XRD), is formed in pure oxygen and exhibits a modulated structure with an approximate supercell: 2 root 2a, 2 root 2b, 4c (electron diffraction, ED). In pure nitrogen, reduced Sb0.9V1.1O4, a = 4.60, c = 3.08 Angstrom (XRD), with the supercell root 2a, root 2b, 2c (ED), is produced. Heating at intermediate partial pressures of oxygen give phases with the basic rutile cell a = b, c (XRD, ED). The formulation of this series is supported by data obtained by Fourier transform infrared spectroscopy. Under reducing conditions (in pure nitrogen), a solid solution series of Sb0.9V1.1O4 and VO2 is observed, i.e., Sb0.9-yV1.1+yO4, 0 < y < 0.7. Vanadium-rich Sb0.2V1.8O4, with a = 4.55, c = 2.99 Angstrom (XRD), exhibits a basic rutile lattice with diffuse intensity between Bragg spots (ED). (C) 1995 Academic Press, Inc.
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| 38. |
- Landa-Marban, David, et al.
(författare)
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An Upscaled Model for Permeable Biofilm in a Thin Channel and Tube
- 2020
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Ingår i: Transport in Porous Media. - : Springer. - 0169-3913 .- 1573-1634. ; 132:1, s. 83-112
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we derive upscaled equations for modeling biofilm growth in porous media. The resulting macroscale mathematical models consider permeable multi-species biofilm including water flow, transport, detachment and reactions. The biofilm is composed of extracellular polymeric substances (EPS), water, active bacteria and dead bacteria. The free flow is described by the Stokes and continuity equations, and the water flux inside the biofilm by the Brinkman and continuity equations. The nutrients are transported in the water phase by convection and diffusion. This pore-scale model includes variations in the biofilm composition and size due to reproduction of bacteria, production of EPS, death of bacteria and shear forces. The model includes a water-biofilm interface between the free flow and the biofilm. Homogenization techniques are applied to obtain upscaled models in a thin channel and a tube, by investigating the limit as the ratio of the aperture to the length epsilon of both geometries approaches to zero. As epsilon gets smaller, we obtain that the percentage of biofilm coverage area over time predicted by the pore-scale model approaches the one obtained using the effective equations, which shows a correspondence between both models. The two derived porosity-permeability relations are compared to two empirical relations from the literature. The resulting numerical computations are presented to compare the outcome of the effective (upscaled) models for the two mentioned geometries.
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| 39. |
- Nilsson, J, et al.
(författare)
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Catalysis and structure of the SbVO4/Sb2O4 system for propane ammoxidation
- 1997
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Ingår i: Catalysis Today. - 0920-5861. ; 33:1-3, s. 97-108
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Tidskriftsartikel (refereegranskat)abstract
- Pure Sb0.9V0.9O4 and various preparations with excess of either vanadia or antimony oxide, including mechanical mixtures, have been investigated for propane ammoxidation to acrylonitrile. The catalysts were characterized before and after use in catalysis by various methods, including electron microscopy, infrared spectroscopy and XPS. The catalytic data show that preparations with approximate to SbVO4 and alpha-Sb2O4, compared with the single phases, are more selective to acrylonitrile formation on the condition that the excess antimony oxide is present while synthesising the approximate to SbVO, phase. Considering the catalytic data together with the results from the characterisations, various possibilities are discussed to explain the role of excess alpha-Sb2O4 in propane ammoxidation. Possibilities that can be excluded on rational grounds are catalysis on two phases, or, at grain boundaries, an influence on the morphology of approximate to SbVO4 from alpha-Sb2O4, the formation of alpha-Sb2O4 containing vanadium, defect formation, creation of active sites by the spillover of oxygen, and formation of VSb2O5. Instead, the observed synergy effect is due to the formation of approximate to SbVO4 enriched with antimony at the surface, creating isolation to a suitable level of the V-centres. The explanation is consistent with several observations including catalytic data for a series of vanadium compounds with different vanadium content, showing that structural isolation of the vanadium is necessary for obtaining high selectivity to acrylonitrile.
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| 40. |
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| 41. |
- Olivos-Meza, A., et al.
(författare)
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Suitable characteristics in the selection of human allogeneic chondrocytes donors to increase the number of viable cells for cartilage repair
- 2023
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Ingår i: Cell and Tissue Banking. - : Springer Science and Business Media LLC. - 1389-9333 .- 1573-6814. ; 24:4, s. 725-735
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Tidskriftsartikel (refereegranskat)abstract
- Autologous chondrocyte implantation has shown optimal long-term outcomes in the treatment of cartilage lesions. The challenge for a single-stage approach lies in obtaining sufficient number of cells with high viability. The answer could lie in supplementing or replacing them with allogenic chondrocytes coming from cadaveric donors. In the present work, we aimed to compare the number of viable cells isolated from cartilage of live and cadaveric donors and to determine the suitable characteristics of the best donors. A total of 65 samples from donors aged from 17 to 55 years, either women or men, were enrolled in this study (33 living vs. 32 cadaveric). The mean time of hours from death to processing samples in cadaveric donors was higher compared to live donors (64.3 +/- 17.7 vs. 4.6 +/- 6.4). The number of isolated chondrocytes per gram of cartilage was higher in cadaveric donors (5.389 x 10(6) compared to 3.067 x 10(6) in living donors), whereas the average of cell viability was comparable in both groups (84.16% cadaveric, 87.8% alive). It is possible to obtain viable chondrocytes from cartilage harvested from cadaveric donors, reaching a similar cell number and viability to that obtained from the cartilage of living donors.
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| 42. |
- Soderlind, P., et al.
(författare)
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First-principles elastic constants and phonons of delta-Pu
- 2004
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 70:14
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Tidskriftsartikel (refereegranskat)abstract
- Elastic constants and zone-boundary phonons of delta-plutonium have been calculated within the density-functional theory. The paramagnetic state of delta-Pu is modeled by disordered magnetism utilizing either the disordered local moment or the special quasirandom structure techniques. The anomalously soft C-' as well as a large anisotropy ratio (C-44/C-') of delta-Pu is reproduced by this theoretical model. Also the recently measured phonons for delta-Pu compare relatively well with their theoretical counterpart at the zone boundaries.
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| 43. |
- Söderlind, Per, et al.
(författare)
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High-temperature phonon stabilization of γ-uranium from relativistic first-principles theory
- 2012
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 85:6, s. 060301-
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Tidskriftsartikel (refereegranskat)abstract
- A microscopic explanation for temperature stabilization of the body-centered cubic (bcc) phase in the actinide metals is proposed. We show that for a prototype actinide, uranium, phonon-phonon interaction promotes bcc gamma-U when heated, even though at low temperatures, it is mechanically a strongly unstable phase. Utilizing the recently developed self-consistent ab initio lattice dynamics (SCAILD) scheme in conjunction with highly accurate and fully relativistic density functional theory we obtain phonon dispersion and density of states that compare well with data acquired from inelastic neutron-scattering experiments. The investigation thus establishes that high-temperature lattice dynamics can be modeled from ab initio theory even for complex materials with substantial electron correlation including the actinides.
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| 44. |
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| 45. |
- Wallén, Johan, et al.
(författare)
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Context-dependent demographic and genetic effects of translocation from a captive breeding project
- 2023
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Ingår i: Animal Conservation. - : Wiley. - 1367-9430 .- 1469-1795. ; 26:3, s. 412-423
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Tidskriftsartikel (refereegranskat)abstract
- Translocations are a widespread approach to conserve threatened populations. Given the rapid decline and genetic deterioration of many natural populations, translocations are expected to become even more common in the future. The success of translocations is, however, dependent on multiple context-dependent factors, such as demographic and genetic status, habitat quality and animal behaviour. The Scandinavian arctic fox (Vulpes lagopus) exists in a small, fragmented population that is demographically vulnerable and exposed to inbreeding depression. In the early 2000 s, releases of arctic foxes from the Norwegian Captive Breeding Programme were initiated with the purpose of reintroducing populations to formerly inhabited areas and promoting connectivity. Since 2008/2009, 61 foxes have been released in Junkeren, Norway to re-establish an unoccupied area. We used a combination of field observations and microsatellite genotyping from the release site and two neighbouring subpopulations to investigate (i) the probability of establishment and reproduction for released foxes at the release site and in neighbouring subpopulations, and (ii) the impact on litter size and genetic composition in the recipient populations. Results showed that 18% of the released foxes were established at the release site, or in neighbouring subpopulations and 11.5% reproduced successfully. The extent of post-release dispersal into neighbouring subpopulations was also relatively high (11.5%). During the study period, the number of litters more than doubled in the subpopulations with released foxes contributing 29.5% to this increase, but no clear effect of immigration on litter size was found. There was a slight increase in genetic variation in one of the subpopulations, and a significant decline in genetic divergence between subpopulations. We conclude that despite extensive releases, demographic and genetic effects were highly context-dependent. This study highlights the challenges of reinforcement programmes in small populations and reintroductions to unoccupied sites, especially for highly mobile species in a fragmented landscape.
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| 46. |
- Zhao, Tianyu, et al.
(författare)
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Impact of long-term exposure to ambient ozone on lung function over a course of 20 years (The ECRHS study) : a prospective cohort study in adults
- 2023
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Ingår i: The Lancet Regional Health. - : Elsevier. - 2666-7762. ; 34
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: While the adverse effects of short-term ambient ozone exposure on lung function are well-documented, the impact of long-term exposure remains poorly understood, especially in adults.METHODS: We aimed to investigate the association between long-term ozone exposure and lung function decline. The 3014 participants were drawn from 17 centers across eight countries, all of which were from the European Community Respiratory Health Survey (ECRHS). Spirometry was conducted to measure pre-bronchodilation forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC) at approximately 35, 44, and 55 years of age. We assigned annual mean values of daily maximum running 8-h average ozone concentrations to individual residential addresses. Adjustments were made for PM2.5, NO2, and greenness. To capture the ozone-related change in spirometric parameters, our linear mixed effects regression models included an interaction term between long-term ozone exposure and age.FINDINGS: Mean ambient ozone concentrations were approximately 65 μg/m³. A one interquartile range increase of 7 μg/m³ in ozone was associated with a faster decline in FEV1 of -2.08 mL/year (95% confidence interval: -2.79, -1.36) and in FVC of -2.86 mL/year (-3.73, -1.99) mL/year over the study period. Associations were robust after adjusting for PM2.5, NO2, and greenness. The associations were more pronounced in residents of northern Europe and individuals who were older at baseline. No consistent associations were detected with the FEV1/FVC ratio.INTERPRETATION: Long-term exposure to elevated ambient ozone concentrations was associated with a faster decline of spirometric lung function among middle-aged European adults over a 20-year period.
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