| 1. |
- Nordanstig, Joakim, et al.
(author)
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Mortality with Paclitaxel-Coated Devices in Peripheral Artery Disease.
- 2020
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In: The New England journal of medicine. - : Massachusetts Medical Society. - 1533-4406 .- 0028-4793. ; 383, s. 2538-46
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Journal article (peer-reviewed)abstract
- The results of a recent meta-analysis aroused concern about an increased risk of death associated with the use of paclitaxel-coated angioplasty balloons and stents in lower-limb endovascular interventions for symptomatic peripheral artery disease.We conducted an unplanned interim analysis of data from a multicenter, randomized, open-label, registry-based clinical trial. At the time of the analysis, 2289 patients had been randomly assigned to treatment with drug-coated devices (the drug-coated-device group, 1149 patients) or treatment with uncoated devices (the uncoated-device group, 1140 patients). Randomization was stratified according to disease severity on the basis of whether patients had chronic limb-threatening ischemia (1480 patients) or intermittent claudication (809 patients). The single end point for this interim analysis was all-cause mortality.No patients were lost to follow-up. Paclitaxel was used as the coating agent for all the drug-coated devices. During a mean follow-up of 2.49 years, 574 patients died, including 293 patients (25.5%) in the drug-coated-device group and 281 patients (24.6%) in the uncoated-device group (hazard ratio, 1.06; 95% confidence interval, 0.92 to 1.22). At 1 year, all-cause mortality was 10.2% (117 patients) in the drug-coated-device group and 9.9% (113 patients) in the uncoated-device group. During the entire follow-up period, there was no significant difference in the incidence of death between the treatment groups among patients with chronic limb-threatening ischemia (33.4% [249 patients] in the drug-coated-device group and 33.1% [243 patients] in the uncoated-device group) or among those with intermittent claudication (10.9% [44 patients] and 9.4% [38 patients], respectively).In this randomized trial in which patients with peripheral artery disease received treatment with paclitaxel-coated or uncoated endovascular devices, the results of an unplanned interim analysis of all-cause mortality did not show a difference between the groups in the incidence of death during 1 to 4 years of follow-up. (Funded by the Swedish Research Council and others; ClinicalTrials.gov number, NCT02051088.).
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| 2. |
- Abrahamsson, Erik, 1974, et al.
(author)
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A new reaction path for the C + NO reaction: dynamics on the 4A'' potential-energy surface.
- 2008
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In: Physical chemistry chemical physics : PCCP. - : Royal Society of Chemistry (RSC). - 1463-9076 .- 1463-9084. ; 10:30, s. 4400-9
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Journal article (peer-reviewed)abstract
- We present a new reaction path without significant barriers for the C + NO reaction, forming ground state N((4)S) and CO. Electronic structure (CASPT2) calculations have been performed for the two lowest (4)A'' states of the CNO system. The lowest of these states shows no significant barriers against reaction in the C + NO or O + CN channels. This surface has been fitted to an analytical function using a many-body expansion. Using this surface, and the previously published (2)A' and (2)A'' surfaces [Andersson et al., Phys. Chem. Chem. Phys., 2000, 2, 613; Andersson et al., Chem. Phys., 2000, 259, 99], we have performed quasiclassical trajectory (QCT) calculations, obtaining rate coefficients for the C((3)P) + NO(X(2)Pi) --> CO(X(1)Sigma(+)) + N((4)S,(2)D) and C((3)P) + NO(X(2)Pi) --> O((3)P) + CN(X(2)Sigma(+)) reactions. We have also simulated the crossed molecular beam experiments of Naulin et al. [Chem. Phys., 1991, 153, 519] The inclusion of the (4)A'' surface in the QCT calculations gives excellent agreement with experiments. This is the first time an adiabatic pathway from C((3)P) + NO(X(2)Pi) to CO(X(1)Sigma(+))+N((4)S) has been reported.
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| 3. |
- Abrahamsson, Erik, 1974, et al.
(author)
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Classical and quantum dynamics of the O+CN reaction
- 2006
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In: Chemical Physics. - : Elsevier BV. - 0301-0104. ; 324:2-3, s. 507-514
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Journal article (peer-reviewed)abstract
- Electronic structure (CASPT2) calculations have been performed for the (2)Pi and (4)Sigma(-) states of the NCO system. To create the potential energy surfaces, the generalized discrete variable representation (GDVR) method has been used. Wave packet calculations have been performed for the collinear O + CN reaction on both surfaces. These are the first reported quantum dynamics calculations on this reaction. State-to-state reaction probabilities are presented. On the (2)Pi surface, which has an almost 6 eV deep well, we obtain structure in the reaction probabilities at low kinetic energies but at higher energies they are smooth. The (4)Sigma(-) surface is highly exoergic and vibrationally non-adiabatic dynamics is observed. The (4)Sigma(-) surface has an early barrier and as a result we find that translational energy more efficiently promotes the reaction than vibrational energy does. The wave packet results are compared with QCT results. Generally the agreement is good as would be expected but some notable differences are found, particularly for reaction out of the vibrational ground state. (c) 2005 Elsevier B.V. All rights reserved.
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| 4. |
- Abrahamsson, Erik, 1974, et al.
(author)
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Dynamics of the O + CN Reaction and N + CO Scattering on Two Coupled Surfaces
- 2009
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In: J. Phys. Chem. A. - : American Chemical Society (ACS). - 1089-5639 .- 1520-5215. ; 113:52, s. 14824-14830
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Journal article (peer-reviewed)abstract
- Spin−orbit coupling between the two collinear 2Π and 4Σ− potential energy surfaces for the NCO system are calculated using the RASSI method with CASSCF wave functions as basis set. The GDVR method has been used to interpolate a spin−orbit coupling surface. Wave packet and quasi-classical trajectory surface hopping calculations have been performed and compared for both the O(3P) + CN(X2Σ+) → N(4S) + CO(X1Σ+) reaction and for electronically inelastic scattering in the N + CO channels. The O + CN nonadiabatic reaction probabilities are small. The wavepacket study gives a resonance structure. Also for the N + CO electronically inelastic scattering the wave packet calculations give a distinct resonance structure with peak transition probabilities up to around 10%, which is somewhat lower than the trajectory surface hopping results.
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| 5. |
- Andersson, Stefan, 1973, et al.
(author)
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Comparison of quantum dynamics and quantum transition state theory estimates of the H + CH4 reaction rate.
- 2009
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In: The journal of physical chemistry. A. - : American Chemical Society (ACS). - 1520-5215 .- 1089-5639. ; 113:16, s. 4468-78
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Journal article (peer-reviewed)abstract
- Thermal rate constants are calculated for the H + CH(4) --> CH(3) + H(2) reaction employing the potential energy surface of Espinosa-Garcia (Espinosa-Garcia, J. J. Chem. Phys. 2002, 116, 10664). Two theoretical approaches are used. First, we employ the multiconfigurational time-dependent Hartree method combined with flux correlation functions. In this way rate constants in the range 225-400 K are obtained and compared with previous results using the same theoretical method but the potential energy surface of Wu et al. (Wu, T.; Werner, H.-J.; Manthe, U. Science 2004, 306, 2227). It is found that the Espinosa-Garcia surface results in larger rate constants. Second, a harmonic quantum transition state theory (HQTST) implementation of instanton theory is used to obtain rate constants in a temperature interval from 20 K up to the crossover temperature at 296 K. The HQTST estimates are larger than MCTDH ones by a factor of about three in the common temperature range. Comparison is also made with various tunneling corrections to transition state theory and quantum instanton theory.
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| 6. |
- Andersson, Stefan, 1973, et al.
(author)
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Computational studies of the kinetics of the C+NO and O+CN reactions
- 2003
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In: Journal of Physical Chemistry A. - : American Chemical Society (ACS). - 1089-5639 .- 1520-5215. ; 107:28, s. 5439-5447
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Journal article (peer-reviewed)abstract
- Thermal rate coefficients for the reactions C(3P) + NO(X2Π) → CN(X2Σ+) + O(3P), C(3P) + NO(X2Π) → CO(X1Σ+) + N(2D), and O(3P) + CN(X2Σ+) → CO(X1Σ+) + N(2D) in the temperature range from 5 to 5000 K have been obtained using quasiclassical trajectory calculations. Results are reported for two ab initio potential energy surfaces corresponding to states of 2A‘ and 2A‘ ‘ symmetry. Good agreement between calculated and experimental rate coefficients are obtained for the C + NO reactions for all temperatures, whereas the rate coefficient for the O + CN reaction at room temperature is larger than that found experimentally. The dynamics is considerably different on the two potential energy surfaces with the 2A‘ ‘ giving rate coefficients in better agreement with experiments. The quality of the potential energy surfaces are discussed in the light of new electronic structure calculations including spin−orbit coupling.
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| 7. |
- Andersson, Stefan, 1973, et al.
(author)
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Rotational Transitions of CO+ Induced by Atomic Hydrogen
- 2008
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In: The Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 678, s. 1042-1048
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Journal article (peer-reviewed)abstract
- The CO+ molecular ion has been observed in photon-dominated regions. Recent modeling has not been able to explain the abundances of CO+ in these regions. The most abundant collision partners are believed to be hydrogen atoms, hydrogen molecules, and electrons. The reactions of these species with CO+ have been studied previously and found to be fast. The only inelastic processes studied before were collisions of CO+ with electrons. Here we investigate the inelastic collisions of CO+ with hydrogen atoms. We argue that this can be done on the lowest triplet electronic state. This implies that CO+ ions, in a hydrogen atom dominated surrounding, experiences a few inelastic collisions before reacting. Rotationally inelastic state-to-state cross sections ( ) are presented together with state-resolved thermal rate coefficients. The results suggest that the rotationally inelastic collision cross sections can be of comparable magnitude to the reactive ones. Implications for the rotational temperature of CO+ in PDRs are discussed. To perform the calculations, a potential energy surface is fitted using the reproducing-kernel Hilbert space method based on multireference configuration-interaction calculations employing the aug-cc-pVQZ basis set.
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| 8. |
- Andrä, Heiko, et al.
(author)
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Micromechanical network model for the evaluation of quality controls of paper
- 2011
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In: Progress in Paper Physics Seminar. - 9783851251630 ; , s. 49-55
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Conference paper (peer-reviewed)abstract
- In this paper, we discuss the challenges in modelling and simulating infinitesimal and large deformations of cellulose fiber networks, mainly in the context of the prediction of quality controls for paper.Understanding the influence and sensitivity of macroscopic production parameters like grammage and thickness of paperboard and understanding the influence of the fiber suspension on the quality of paper is important for the development of better papers and for preserving raw materials and energy.The new simulation framework consists of the virtual stochastic paper structure generator PaperGeo, that was integrated in the GeoDict 1 software suite, and the finite element solver FeelMath (Finite Elements for Elastic Materials and Homogenization) for solving the equations of elasticity. The fibers and the contacts are modelled by using geometrically exact beams of Simo-type [1].The microstructural model and the fiber network model are validated against standard measurements of existing papers in the following way: At first we perform tensile and bending tests to measure the macroscopic stress-strain relations. In the next step we apply a representative macroscopic stress or strain onto the boundaries of realizations of the stochastic fiber network model and compute by homogenization the effective (stiffness) coefficients. Finally we compare the numerical results with the measurements.This procedure can also be used for an identification of elastic parameters on the microscale and to study the sensitivity of the effective (macroscopic) stiffness with regard to the parameters of the microstructure
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