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- Ferreira, Mjv, et al.
(author)
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Poster Session 3 : Tuesday 5 May 2015, 08
- 2015
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In: European Heart Journal Cardiovascular Imaging. - : Oxford University Press (OUP). - 2047-2404 .- 2047-2412. ; 16 Suppl 1
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Journal article (peer-reviewed)
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| 3. |
- Nguyen, Thanh N, et al.
(author)
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Global Impact of the COVID-19 Pandemic on Stroke Volumes and Cerebrovascular Events: A 1-Year Follow-up.
- 2023
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In: Neurology. - 1526-632X. ; 100:4
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Journal article (peer-reviewed)abstract
- Declines in stroke admission, IV thrombolysis (IVT), and mechanical thrombectomy volumes were reported during the first wave of the COVID-19 pandemic. There is a paucity of data on the longer-term effect of the pandemic on stroke volumes over the course of a year and through the second wave of the pandemic. We sought to measure the effect of the COVID-19 pandemic on the volumes of stroke admissions, intracranial hemorrhage (ICH), IVT, and mechanical thrombectomy over a 1-year period at the onset of the pandemic (March 1, 2020, to February 28, 2021) compared with the immediately preceding year (March 1, 2019, to February 29, 2020).We conducted a longitudinal retrospective study across 6 continents, 56 countries, and 275 stroke centers. We collected volume data for COVID-19 admissions and 4 stroke metrics: ischemic stroke admissions, ICH admissions, IVT treatments, and mechanical thrombectomy procedures. Diagnoses were identified by their ICD-10 codes or classifications in stroke databases.There were 148,895 stroke admissions in the 1 year immediately before compared with 138,453 admissions during the 1-year pandemic, representing a 7% decline (95% CI [95% CI 7.1-6.9]; p < 0.0001). ICH volumes declined from 29,585 to 28,156 (4.8% [5.1-4.6]; p < 0.0001) and IVT volume from 24,584 to 23,077 (6.1% [6.4-5.8]; p < 0.0001). Larger declines were observed at high-volume compared with low-volume centers (all p < 0.0001). There was no significant change in mechanical thrombectomy volumes (0.7% [0.6-0.9]; p = 0.49). Stroke was diagnosed in 1.3% [1.31-1.38] of 406,792 COVID-19 hospitalizations. SARS-CoV-2 infection was present in 2.9% ([2.82-2.97], 5,656/195,539) of all stroke hospitalizations.There was a global decline and shift to lower-volume centers of stroke admission volumes, ICH volumes, and IVT volumes during the 1st year of the COVID-19 pandemic compared with the prior year. Mechanical thrombectomy volumes were preserved. These results suggest preservation in the stroke care of higher severity of disease through the first pandemic year.This study is registered under NCT04934020.
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| 5. |
- Reid, Thomas K., et al.
(author)
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First-principles modeling of binary layered topological insulators : Structural optimization and exchange-correlation functionals
- 2020
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In: Physical Review B. - : AMER PHYSICAL SOC. - 2469-9950 .- 2469-9969. ; 101:8
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Journal article (peer-reviewed)abstract
- Topological insulators (TIs) are materials that are insulating in the bulk but have zero band-gap surface states with linear dispersion and are protected by time-reversal symmetry. These unique characteristics could pave the way for many promising applications that include spintronic devices and quantum computations. It is important to understand and theoretically describe TIs as accurately as possible to predict properties. Quantum mechanical approaches, specifically first-principles density-functional-theory (DFT)-based methods, have been used extensively to model electronic properties of TIs. Here we provide a comprehensive assessment of a variety of DFT formalisms and how these capture the electronic structure of TIs. We concentrate on Bi2Se3 and Bi2Te3 as examples of prototypical TI materials. We find that the generalized gradient approximation (GGA) and kinetic density functional (metaGGA) increase the thickness of the TI slab, whereas we see the opposite behavior in DFT computations using LDA. Accounting for van der Waals (vdW) interactions overcomes the apparent over-relaxations and retraces the atomic positions toward the bulk. Based on a systematic computational study, we show that GGA with vdW treatment is an appropriate method for structural optimization. However, the vdW corrections recover the experimental bulk parameters, and do not influence the charge density implicitly. Thus, electronic structures derived from the base GGA functional, employing experimental lattice parameters, is sufficient.
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| 6. |
- Reid, Thomas K., et al.
(author)
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Inducing quantum phase transitions in nontopological insulators via atomic control of substructural elements
- 2023
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In: Physical Review B. - : American Physical Society (APS). - 2469-9950 .- 2469-9969. ; 108:23
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Journal article (peer-reviewed)abstract
- Topological insulators are an important family of quantum materials that exhibit a Dirac point (DP) in the surface band structure but have a finite band gap in bulk. A large degree of spin-orbit interaction and low band gap is a prerequisite for stabilizing DPs on selective atomically flat cleavage planes. Tuning of the DP in these materials has been suggested via modifications to the atomic structure of the entire system. Using the example of As2Te3 and ZnTe5, which are not TIs, we show that a quantum phase transition can be induced in atomically flat and stepped surfaces, for As2Te3 and ZrTe5, respectively. This is achieved by establishing a framework for controlling electronic properties that is focused on local perturbations at key locations that we call substructural elements. We exemplify this framework through a unique method of isovalent sublayer anion doping and biaxial strain.
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