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Sökning: WFRF:(Mayrhofer T)

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  • Karady, Julia, et al. (författare)
  • Coronary Plaque in People With HIV vs Non-HIV Asymptomatic Community and Symptomatic Higher-Risk Populations
  • 2024
  • Ingår i: JACC: Advances. - 2772-963X. ; 3:6
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: People with HIV (PWH) have a high burden of coronary plaques; however, the comparison to people without known HIV (PwoH) needs clarification. Objectives: The purpose of this study was to determine coronary plaque burden/phenotype in PWH vs PwoH. Methods: Nonstatin using participants from 3 contemporary populations without known coronary plaques with coronary CT were compared: the REPRIEVE (Randomized Trial to Prevent Vascular Events in HIV) studying PWH without cardiovascular symptoms at low-to-moderate risk (n = 755); the SCAPIS (Swedish Cardiopulmonary Bioimage Study) of asymptomatic community PwoH at low-to-intermediate cardiovascular risk (n = 23,558); and the PROMISE (Prospective Multicenter Imaging Study for Evaluation of Chest Pain) of stable chest pain PwoH (n = 2,291). The coronary plaque prevalence on coronary CT was compared, and comparisons were stratified by 10-year atherosclerotic cardiovascular disease (ASCVD) risk, age, and coronary artery calcium (CAC) presence. Results: Compared to SCAPIS and PROMISE PwoH, REPRIEVE PWH were younger (50.8 ± 5.8 vs 57.3 ± 4.3 and 60.0 ± 8.0 years; P < 0.001) and had lower ASCVD risk (5.0% ± 3.2% vs 6.0% ± 5.3% and 13.5% ± 11.0%; P < 0.001). More PWH had plaque compared to the asymptomatic cohort (48.5% vs 40.3%; P < 0.001). When stratified by ASCVD risk, PWH had more plaque compared to SCAPIS and a similar prevalence of plaque compared to PROMISE. CAC = 0 was more prevalent in PWH (REPRIEVE 65.2%; SCAPIS 61.6%; PROMISE 49.6%); among CAC = 0, plaque was more prevalent in PWH compared to the PwoH cohorts (REPRIEVE 20.8%; SCAPIS 5.4%; PROMISE 12.3%, P < 0.001). Conclusions: Asymptomatic PWH in REPRIEVE had more plaque than asymptomatic PwoH in SCAPIS but had similar prevalence to a higher-risk stable chest pain cohort in PROMISE. In PWH, CAC = 0 does not reliably exclude plaque.
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  • Riedl, H., et al. (författare)
  • Influence of carbon deficiency on phase formation of super-hard TaCy thin films
  • 2018
  • Ingår i: Scripta Materialia. - : PERGAMON-ELSEVIER SCIENCE LTD. - 1359-6462 .- 1872-8456. ; 149, s. 150-154
  • Tidskriftsartikel (refereegranskat)abstract
    • Using nonreactive sputter deposition allows the preparation of single-phase fcc structured TaCy thin films over a wide compositional range with y between 0.63 and 1.04. Among this composition range, the C-deficient TaC0.78 exhibits the highest as deposited hardness of 43.4 +/- 0.65 GPa combined with the highest thermal stability. Even after vacuum annealing to 2400 degrees C, no vacancy-ordered or faulted Ta-C based phases can be detected. The stabilization of carbon deficient fcc structured TaCy near y of about 0.75, revealed the decisive character of vacancy engineered thin films materials for ultra-high temperature applications. (C) 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
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  • Biurrun, Idoia, et al. (författare)
  • Benchmarking plant diversity of Palaearctic grasslands and other open habitats
  • 2021
  • Ingår i: Journal of Vegetation Science. - Oxford : John Wiley & Sons. - 1100-9233 .- 1654-1103. ; 32:4
  • Tidskriftsartikel (refereegranskat)abstract
    • Journal of Vegetation Science published by John Wiley & Sons Ltd on behalf of International Association for Vegetation Science.Aims: Understanding fine-grain diversity patterns across large spatial extents is fundamental for macroecological research and biodiversity conservation. Using the GrassPlot database, we provide benchmarks of fine-grain richness values of Palaearctic open habitats for vascular plants, bryophytes, lichens and complete vegetation (i.e., the sum of the former three groups). Location: Palaearctic biogeographic realm. Methods: We used 126,524 plots of eight standard grain sizes from the GrassPlot database: 0.0001, 0.001, 0.01, 0.1, 1, 10, 100 and 1,000 m2 and calculated the mean richness and standard deviations, as well as maximum, minimum, median, and first and third quartiles for each combination of grain size, taxonomic group, biome, region, vegetation type and phytosociological class. Results: Patterns of plant diversity in vegetation types and biomes differ across grain sizes and taxonomic groups. Overall, secondary (mostly semi-natural) grasslands and natural grasslands are the richest vegetation type. The open-access file ”GrassPlot Diversity Benchmarks” and the web tool “GrassPlot Diversity Explorer” are now available online (https://edgg.org/databases/GrasslandDiversityExplorer) and provide more insights into species richness patterns in the Palaearctic open habitats. Conclusions: The GrassPlot Diversity Benchmarks provide high-quality data on species richness in open habitat types across the Palaearctic. These benchmark data can be used in vegetation ecology, macroecology, biodiversity conservation and data quality checking. While the amount of data in the underlying GrassPlot database and their spatial coverage are smaller than in other extensive vegetation-plot databases, species recordings in GrassPlot are on average more complete, making it a valuable complementary data source in macroecology. © 2021 The Authors.
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  • Fritze, Stefan, et al. (författare)
  • Elemental distribution and fracture properties of magnetron sputtered carbon supersaturated tungsten films
  • 2024
  • Ingår i: Surface & Coatings Technology. - : Elsevier BV. - 0257-8972 .- 1879-3347. ; 477
  • Tidskriftsartikel (refereegranskat)abstract
    • The combination of strength and toughness is a major driving force for alloy design of protective coatings, and nanocrystalline tungsten (W)-alloys have shown to be promising candidates for combining strength and toughness. Here we investigate the elemental distribution and the fracture toughness of carbon (C) alloyed W thin films prepared by non-reactive magnetron sputtering. W:C films with up to ~4 at.% C crystallize in a body-centered-cubic structure with a strong 〈hh0〉texture, and no additional carbide phases are observed in the diffraction pattern. Atom probe tomography and X-ray photoelectron spectroscopy confirmed the formation of such a supersaturated solid solution. The pure W film has a hardness ~13 GPa and the W:C films exhibit a peak hardness of ~24 GPa. In-situ micromechanical cantilever bending tests show that the fracture toughness decreases from ~4.5 MPa·m1/2 for the W film to ~3.1 MPa·m1/2 for W:C films. The results show that C can significantly enhance the hardness of W thin films while retaining a high fracture toughness.
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  • Fuger, C., et al. (författare)
  • Influence of Ta on the oxidation resistance of WB2-z coatings
  • 2021
  • Ingår i: Journal of Alloys and Compounds. - : Elsevier. - 0925-8388 .- 1873-4669. ; 864
  • Tidskriftsartikel (refereegranskat)abstract
    • Ternary W1-x TaxB2-z is a promising protective coating material possessing enhanced ductile character and phase stability compared to closely related binaries. Here, the oxidation resistance of W1-xTaxB2-z thin films was experimentally investigated at temperatures up to 700 degrees C. Ta alloying in sputter deposited WB2-z coatings led to decelerated oxide scale growth and a changed growth mode from paralinear to a more linear (but retarded) behavior with increasing Ta content. The corresponding rate constants decrease from k(p)* = 6.3.10(-4) mu m(2)/s for WB2-z to k(p)* = 1.1.10(-4) mu m(2)/s for W0.66Ta0.34B2-z as well as k(1) = 2.6.10(-5) mu m/s for TaB2-z, underlined by decreasing scale thicknesses ranging from 1170 nm (WB2-z), over 610 nm (W0.66Ta0.34B2-z) to 320 nm (TaB2-z) after 10 min at 700 degrees C. Dense and adherent scales exhibit an increased tantalum content (columnar oxides), which suppresses the volatile character of tungsten-rich as well as boron oxides, hence being a key-factor for enhanced oxidation resistance. Thus, adding Ta (in the range of x = 0.2-0.3) to a-structured WB2-z does not only positively influence the ductile character and thermal stability but also drastically increases the oxidation resistance.
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  • Glechner, T., et al. (författare)
  • Tuning structure and mechanical properties of Ta-C coatings by N-alloying and vacancy population
  • 2018
  • Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 8
  • Tidskriftsartikel (refereegranskat)abstract
    • Tailoring mechanical properties of transition metal carbides by substituting carbon with nitrogen atoms is a highly interesting approach, as thereby the bonding state changes towards a more metallic like character and thus ductility can be increased. Based on ab initio calculations we could prove experimentally, that up to a nitrogen content of about 68% on the non-metallic sublattice, Ta-C-N crystals prevail a face centered cubic structure for sputter deposited thin films. The cubic structure is partly stabilized by non-metallic as well as Ta vacancies-the latter are decisive for nitrogen rich compositions. With increasing nitrogen content, the originally super-hard fcc-TaC0.71 thin films soften from 40 GPa to 26 GPa for TaC0.33N0.67, accompanied by a decrease of the indentation modulus. With increasing nitrogen on the non-metallic sublattice (hence, decreasing C) the damage tolerance of Ta-C based coatings increases, when characterized after the Pugh and Pettifor criteria. Consequently, varying the non-metallic sublattice population allows for an effective tuning and designing of intrinsic coating properties.
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  • Hahn, R., et al. (författare)
  • Unraveling the superlattice effect for hexagonal transition metal diboride coatings
  • 2023
  • Ingår i: Scripta Materialia. - : Elsevier. - 1359-6462 .- 1872-8456. ; 235
  • Tidskriftsartikel (refereegranskat)abstract
    • Superlattice structures enable the simultaneous enhancement in hardness (H) and fracture toughness (KIC) of ceramic-like coatings. While a deeper understanding of this effect has been gained for fcc-structured transition metal nitrides (TMN), hardly any knowledge is available for hexagonal diborides (TMB2). Here we show that superlattices can-similarly to nitrides-increase the hardness and toughness of diboride films. For this purpose, we deposited TiB2/WB2 and TiB2/ZrB2 superlattices with different bilayer periods (?) by non-reactive sputtering. Nanoindentation and in-situ microcantilever bending tests yield a distinct H peak for the TiB2/WB2 system (45.5 & PLUSMN; 1.3 GPa for ? = 6 nm) but no increase in KIC related to a difference in shear moduli (112 GPa). Contrary, the TiB2/ZrB2 system shows no peak in H, but for KIC with 3.70 & PLUSMN; 0.26 MPa & BULL;m1/2 at ? = 4 nm originating from differences in lattice spacing (0.14 & ANGS;), hence causing coherent stresses retarding crack growth.
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  • Hu, Chun, et al. (författare)
  • Influence of co-sputtering AlB2 to TaB2 on stoichiometry of non-reactively sputtered boride thin films
  • 2024
  • Ingår i: Materials Research Letters. - : TAYLOR & FRANCIS INC. - 2166-3831. ; 12:8, s. 561-570
  • Tidskriftsartikel (refereegranskat)abstract
    • Transition metal diboride thin films are promising functional materials for their outstanding mechanical properties and thermal stability. By combining experiment and simulations, we discuss angular distribution of the sputtered species, their scattering in the gas phase, re-sputtering and potential evaporation from the grown films for the complex evolution of film compositions, as well as energetic preference for vacancy formation and competing phases as factors for governing the phase constitution. By co-sputtering from two compound targets, we developed phase-pure crystalline (Ta,Al)B2 solid solution thin films and correlate the stoichiometry changes with the evolution of their microstructure, hardness, and elastic modulus. {GRAPHICAL ABSTRACT}
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  • Hurtado, P., et al. (författare)
  • Disentangling functional trait variation and covariation in epiphytic lichens along a continent-wide latitudinal gradient
  • 2020
  • Ingår i: Proceedings of the Royal Society of London. Biological Sciences. - : ROYAL SOC. - 0962-8452 .- 1471-2954. ; 287:1922
  • Tidskriftsartikel (refereegranskat)abstract
    • Characterizing functional trait variation and covariation, and its drivers, is critical to understand the response of species to changing environmental conditions. Evolutionary and environmental factors determine how traits vary among and within species at multiple scales. However, disentangling their relative contribution is challenging and a comprehensive trait-environment framework addressing such questions is missing in lichens. We investigated the variation in nine traits related to photosynthetic performance, water use and nutrient acquisition applying phylogenetic comparative analyses in lichen epiphytic communities on beech across Europe. These poikilohydric organisms offer a valuable model owing to their inherent limitations to buffer contrasting environmental conditions. Photobiont type and growth form captured differences in certain physiological traits whose variation was largely determined by evolutionary processes (i.e. phylogenetic history), although the intraspecific component was non-negligible. Seasonal temperature fluctuations also had an impact on trait variation, while nitrogen content depended on photobiont type rather than nitrogen deposition. The inconsistency of trait covariation among and within species prevented establishing major resource use strategies in lichens. However, we did identify a general pattern related to the water-use strategy. Thus, to robustly unveil lichen responses under different climatic scenarios, it is necessary to incorporate both among and within-species trait variation and covariation.
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  • Kirnbauer, A., et al. (författare)
  • Mechanical properties and thermal stability of reactively sputtered multi-principal-metal Hf-Ta-Ti-V-Zr nitrides
  • 2020
  • Ingår i: Surface & Coatings Technology. - : ELSEVIER SCIENCE SA. - 0257-8972 .- 1879-3347. ; 389
  • Tidskriftsartikel (refereegranskat)abstract
    • Crystalline (Hf,Ta,Ti,V,Zr)N nitride thin films, with a high-entropy metal-sublattice, were synthesized at 440 degrees C by reactive magnetron sputtering using an equimolar Hf-Ta-Ti-V-Zr-compound target. The coatings are single-phase fcc structured mono-nitrides for N-2/(Ar + N-2) flow-rate-ratios (f(N2)) between 30 and 45%. For higher f(N2) a small fraction of a second phase (next to the fcc matrix) can be detected by X-ray diffraction (XRD) and selected area electron diffraction (SAED). All coatings studied (prepared with f(N2) between 30 and 60%) show similar chemical compositions and hardness (H) values between 30.0 and 34.0 GPa with indentation moduli of similar to 460 GPa. Atom probe tomography (APT) indicates a homogenous distribution of all elements within our fcc-(Hf,Ta,Ti,V,Zr)N even after vacuum-annealing at 1300 degrees C. While H decreased from 32.5 to 28.1 GPa by this annealing treatment, the coating is still single-phase fcc structured with a defect density (expressed by XRD and SAED features, transmission electron microscopy contrast, and grain sizes) comparable to the as-deposited state. Only after vacuum-annealing at 1500 degrees C, XRD and APT reveal the formation of hexagonal structured (Ta,V)(2)N. The onset of nitrogen-loss - detected by thermogravimetric analysis - is similar to 1350 degrees C. Based on our results we can conclude that the sluggish diffusion within our fcc-(Hf,Ta,Ti,V,Zr)N warrants the single-phase fcc structure up to 1300 degrees C, although ab initio based calculations would suggest the lower-entropy products [fcc-(Hf,Zr)N, fcc-(Ta,V)N, and fcc-TiN] and [fcc-(Hf,Zr)N and fcc-(Ta,Ti,V)N] to be energetically more stable up to 1302 K.
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  • Lasfargues, H., et al. (författare)
  • Non-reactively sputtered ultra-high temperature Hf-C and Ta-C coatings
  • 2017
  • Ingår i: Surface & Coatings Technology. - : ELSEVIER SCIENCE SA. - 0257-8972 .- 1879-3347. ; 309, s. 436-444
  • Tidskriftsartikel (refereegranskat)abstract
    • Transition metal carbides are known for their exceptional thermal stability and mechanical properties, notably governed by the carbon content and the prevalent vacancies on the non-metallic sublattice. However, when using reactive deposition techniques, the formation of amorphous C-containing phases is often observed. Here, we show that non-reactive magnetron sputtering of HfC0.89 or TaC0.92 targets lead to fully crystalline coatings. Their C content depends on the target-to-substrate alignment and globally increases from HfC0.66 to HfC0.76 and from TaC0.69 to TaC0.75 with increasing bias potential from floating to - 100 V, respectively, when using a substrate temperature T-sub of 500 degrees C. Increasing T-sub to 700 degrees C leads to variations from TaC0.71 to TaC0.81. All HfCy films are single-phase face-centered cubic, whereas the TaCy films also contain small fractions of the hexagonal Ta2C phase. The highest hardness and indentation modulus among all coatings studied is obtained for TaC0.75 with H = 41.9 +/- 03 GPa and E = 466.8 +/- 15 GPa. Ab initio calculations predict an easy formation of vacancies on the C-sublattice, especially in the Ta-C system, and a temperature driven stabilization of defected structures at high temperatures, with fewer vacancies on the C sublattice for Hf-C than for Ta-C The predicted phase stability is proven up to 2400 C for both systems by annealing experiments in vacuum.
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  • Resl, P., et al. (författare)
  • Large differences in carbohydrate degradation and transport potential in the genomes of lichen fungal symbionts
  • 2022
  • Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 13
  • Tidskriftsartikel (refereegranskat)abstract
    • Lichen symbioses are thought to be stabilized by the transfer of fixed carbon from a photosynthesizing symbiont to a fungus. In other fungal symbioses, carbohydrate subsidies correlate with reductions in plant cell wall-degrading enzymes, but whether this is true of lichen fungal symbionts (LFSs) is unknown. Here, we predict genes encoding carbohydrate-active enzymes (CAZymes) and sugar transporters in 46 genomes from the Lecanoromycetes, the largest extant clade of LFSs. All LFSs possess a robust CAZyme arsenal including enzymes acting on cellulose and hemicellulose, confirmed by experimental assays. However, the number of genes and predicted functions of CAZymes vary widely, with some fungal symbionts possessing arsenals on par with well-known saprotrophic fungi. These results suggest that stable fungal association with a phototroph does not in itself result in fungal CAZyme loss, and lends support to long-standing hypotheses that some lichens may augment fixed CO2 with carbon from external sources.
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  • Zamora, Juan Carlos, et al. (författare)
  • Considerations and consequences of allowing DNA sequence data as types of fungal taxa
  • 2018
  • Ingår i: IMA Fungus. - : INT MYCOLOGICAL ASSOC. - 2210-6340 .- 2210-6359. ; 9:1, s. 167-185
  • Tidskriftsartikel (refereegranskat)abstract
    • Nomenclatural type definitions are one of the most important concepts in biological nomenclature. Being physical objects that can be re-studied by other researchers, types permanently link taxonomy (an artificial agreement to classify biological diversity) with nomenclature (an artificial agreement to name biological diversity). Two proposals to amend the International Code of Nomenclature for algae, fungi, and plants (ICN), allowing DNA sequences alone (of any region and extent) to serve as types of taxon names for voucherless fungi (mainly putative taxa from environmental DNA sequences), have been submitted to be voted on at the 11th International Mycological Congress (Puerto Rico, July 2018). We consider various genetic processes affecting the distribution of alleles among taxa and find that alleles may not consistently and uniquely represent the species within which they are contained. Should the proposals be accepted, the meaning of nomenclatural types would change in a fundamental way from physical objects as sources of data to the data themselves. Such changes are conducive to irreproducible science, the potential typification on artefactual data, and massive creation of names with low information content, ultimately causing nomenclatural instability and unnecessary work for future researchers that would stall future explorations of fungal diversity. We conclude that the acceptance of DNA sequences alone as types of names of taxa, under the terms used in the current proposals, is unnecessary and would not solve the problem of naming putative taxa known only from DNA sequences in a scientifically defensible way. As an alternative, we highlight the use of formulas for naming putative taxa (candidate taxa) that do not require any modification of the ICN.
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