| 1. |
- Edberg, Richard, et al.
(författare)
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Dipolar spin ice under uniaxial pressure
- 2019
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Ingår i: Physical Review B. - : American Physical Society. - 2469-9950 .- 2469-9969. ; 100:14
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Tidskriftsartikel (refereegranskat)abstract
- The magnetically frustrated spin ice family of materials is host to numerous exotic phenomena such as magnetic monopole excitations and macroscopic residual entropy extending to low temperature. A finite-temperature ordering transition in the absence of applied fields has not been experimentally observed in the classical spin ice materials Dy2Ti2O7 and Ho2Ti2O7. Such a transition could be induced by the application of pressure, and in this work we consider the effects of uniaxial pressure on classical spin ice systems. Theoretically, we find that the pressure-induced ordering transition in Dy2Ti2O7 is strongly affected by the dipolar interaction. We also report measurements of the neutron structure factor of Ho2Ti2O7 under pressure and compare the experimental results to the predictions of our theoretical model.
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| 2. |
- Mottahedin, Amin, et al.
(författare)
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Targeting succinate metabolism to decrease brain injury upon mechanical thrombectomy treatment of ischemic stroke
- 2023
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Ingår i: Redox Biology. - : Elsevier BV. - 2213-2317. ; 59
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Tidskriftsartikel (refereegranskat)abstract
- Current treatments for acute ischemic stroke aim to reinstate a normal perfusion in the ischemic territory but can also cause significant ischemia-reperfusion (IR) injury. Previous data in experimental models of stroke show that ischemia leads to the accumulation of succinate, and, upon reperfusion, the accumulated succinate is rapidly oxidized by succinate dehydrogenase (SDH) to drive superoxide production at mitochondrial complex I. Despite this process initiating IR injury and causing further tissue damage, the potential of targeting succinate metabolism to minimize IR injury remains unexplored. Using both quantitative and untargeted high -resolution metabolomics, we show a time-dependent accumulation of succinate in both human and mouse brain exposed to ischemia ex vivo. In a mouse model of ischemic stroke/mechanical thrombectomy mass spectrometry imaging (MSI) shows that succinate accumulation is confined to the ischemic region, and that the accumulated succinate is rapidly oxidized upon reperfusion. Targeting succinate oxidation by systemic infusion of the SDH inhibitor malonate upon reperfusion leads to a dose-dependent decrease in acute brain injury. Together these findings support targeting succinate metabolism upon reperfusion to decrease IR injury as a valuable adjunct to mechanical thrombectomy in ischemic stroke.
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| 3. |
- Alcantara, K. Suarez, et al.
(författare)
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3CaH(2)+4MgB(2) + CaF2 Reactive Hydride Composite as a Potential Hydrogen Storage Material: Hydrogenation and Dehydrogenation Pathway
- 2012
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Ingår i: Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 116:12, s. 7207-7212
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Tidskriftsartikel (refereegranskat)abstract
- A reactive hydride composite (RHC) with initial composition 3CaH(2) + 4MgB(2) + CaF2 was studied by in situ synchrotron radiation powder X-ray diffraction (SR-PXD) and X-ray absorption near edge structure (XANES) at the B K-edge and at the Ca K-edge. The hydrogenation reaction proceeds by an unknown intermediate. No evidence of intermediates was observed during the dehydrogenation reaction. B and Ca K-edge XANES results hint to a closed interaction of CaF2 and Ca(BH4)(2). The main function of CaF2 in the 3CaH(2) + 4MgB(2) + CaF2 RHC is as a dopant for the hydrogenation and dehydrogenation reactions.
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| 4. |
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| 5. |
- Bufasi, Ergi, et al.
(författare)
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Addressing the complexity of spatial teaching: a narrative review of barriers and enablers
- 2024
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Ingår i: Frontiers in Education. - : Frontiers Media SA. - 2504-284X. ; 9
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Forskningsöversikt (refereegranskat)abstract
- Extensive research has established that spatial ability is a crucial factor for achieving success in Science, Technology, Engineering, and Mathematics (STEM). However, challenges that educators encounter while teaching spatial skills remain uncertain. The purpose of this study is to develop a research framework that examines the interrelationships, barriers, and enablers amongst various educational components, including schools, teachers, students, classrooms, and training programs, that are encountered when teaching for spatial ability development. A thorough examination of international research, in combination with a detailed review of the primary Science and Mathematics curricula in Ireland, Latvia, Sweden, and the Netherlands, is undertaken to acquire a more concentrated comprehension of the incorporation of spatial components in the curriculum. The review seeks to establish the fundamental factors that enable or hinder teachers in terms of curriculum, pedagogy, pedagogical content knowledge, and spatialized classroom practices.
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| 6. |
- Casillas Trujillo, Luis, et al.
(författare)
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Interstitial carbon in bcc HfNbTiVZr high-entropy alloy from first principles
- 2020
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Ingår i: Physical Review Materials. - : AMER PHYSICAL SOC. - 2475-9953. ; 4:12
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Tidskriftsartikel (refereegranskat)abstract
- The remarkable mechanical properties of high-entropy alloys can be further improved by interstitial alloying. In this work we employ density functional theory calculations to study the solution energies of dilute carbon interstitial atoms in tetrahedral and octahedral sites in bcc HfNbTiVZr. Our results indicate that carbon interstitials in tetrahedral sites are unstable, and the preferred octahedral sites present a large spread in the energy of solution. The inclusion of carbon interstitials induces large structural relaxations with long-range effects. The effect of local chemical environment on the energy of solution is investigated by performing a local cluster expansion including studies of its correlation with the carbon atomic Voronoi volume. However, the spread in solution energetics cannot be explained with a local environment analysis only pointing towards a complex, long-range influence of interstitial carbon in this alloy.
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| 7. |
- Sorby, M. H., et al.
(författare)
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Reverse Monte Carlo investigation of the temperature dependent deuterium distribution in ZrCr2D4
- 2008
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Ingår i: Journal of Alloys and Compounds. - : Elsevier BV. - 0925-8388 .- 1873-4669. ; 457:1-2, s. 225-232
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Tidskriftsartikel (refereegranskat)abstract
- Short-range correlations in ZrCr2D4 have been investigated with total neutron scattering and Reverse Monte Carlo (RMC) modelling. Data were collected for the deuteride with a disordered deuterium lattice at 298 K, a partly ordered deuterium lattice at 248 K and a fully ordered deuterium lattice at 150 K. Short-range order (SRO) prevents occupation of interstitial sites closer than 2 angstrom from deuterium atoms in the disordered and partly ordered samples in agreement with the Switendick criterion and earlier investigations. The deuterium configurations at 298 and 248 K resemble those found in the fully ordered phase at length scales up to about 4 angstrom. There is no appreciable difference in the short-range deuterium correlations or the extent of the SRO at 248 K as compared to at 298 K. The differences and similarities with the previously investigated compound VD0.8 are discussed.
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