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- Taimour, S., et al.
(author)
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Survival, cardiovascular morbidity, and reinterventions after elective endovascular aortic aneurysm repair in patients with and without diabetes: A nationwide propensity-adjusted analysis
- 2019
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In: Vascular Medicine. - : SAGE Publications. - 1358-863X .- 1477-0377. ; 24:6, s. 539-546
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Journal article (peer-reviewed)abstract
- Epidemiological data indicate decreased risk for development and growth of abdominal aortic aneurysm (AAA) among patients with diabetes mellitus (DM). On the other hand, DM adds to increased cardiovascular (CV) morbidity and mortality. In a nationwide observational cohort study of patients registered in the Swedish Vascular Register and the Swedish National Diabetes Register, we evaluated potential effects of DM on total mortality, CV morbidity, and the need for reintervention after elective endovascular aneurysm repair (EVAR) for AAA. We compared 748 patients with and 2630 without DM with propensity score-adjusted analysis, during a median 4.22 years of follow-up for patients with DM, and 4.05 years for those without. In adjusted analysis, diabetic patients showed higher rates of acute myocardial infarction (AMI) during follow-up (relative risk (RR) 1.44, 95% CI 1.06-1.95; p = 0.02), but lower need for reintervention (RR 0.12, CI 0.02-0.91; p = 0.04). There were no differences in total (RR 0.88, CI 0.74-1.05; p = 0.15) or CV (RR 1.58, CI 0.87-2.86; p = 0.13) mortality, or stroke (RR 0.95, CI 0.68-1.32; p = 0.75) during follow-up. In conclusion, patients with DM had higher rates of AMI and lower need for reintervention after elective EVAR than those without DM, whereas neither total nor CV mortality differed between groups. The putative protective effects of DM towards further AAA enlargement and late sac rupture may help explain the lower need for reintervention and absence of excess mortality.
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- Chernikova, Dina, 1982, et al.
(author)
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The neutron-gamma Feynman variance to mean approach: Gamma detection and total neutron-gamma detection (theory and practice)
- 2015
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In: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. - : Elsevier BV. - 0168-9002. ; 782, s. 47-55
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Journal article (peer-reviewed)abstract
- Two versions of the neutron gamma variance to mean (Feynman-alpha method or Feynman-Y function) formula for either gamma detection only or total neutron gamma detection, respectively, are derived and compared in this paper. The new formulas have particular importance for detectors of either gamma photons or deleclors sensitive to both neutron and gamma radialion. If applied to a plastic or liquid deleclor, he total neutron-gamma detection Feynman-Y expression corresponds Lo a situation where no discrimination is made between neutrons and gamma parlicles. The gamma variance Lo mean formulas are useful when a detector of only gamma radialion is used or when working with a combined neutron-gamma deleclor at high count rates. The theoretical derivation is based on the Chapman-Kolmogorov equation with the inclusion of general reactions and corresponding intensities for neutrons and gammas, but with the inclusion of prompt reactions only. A one energy group approximation is considered. The comparison of the two different theories is made by using reaction intensities obtained in MCNPX simulations with a simplified geometry for two scintillation detectors and a Cf-252-source. In addition, the variance to mean ratios, neutron, gamma and total neutron-gamma are evaluated experimentally for a weak Cf-252 neutron-gamma source, a Cs-137 random gamma source and a Na-22 correlated gamma source. Due to the focus being on the possibility of using neutron-gamma variance to mean theories for both reactor and safeguards applications, we limited the present study to the general analytical expressions for Feynman-alpha formulas.
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- Fiorina, B., et al.
(author)
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Challenging modeling strategies for LES of non-adiabatic turbulent stratified combustion
- 2015
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In: Combustion and Flame. - : Elsevier BV. - 0010-2180 .- 1556-2921. ; 162:11, s. 4264-4282
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Journal article (peer-reviewed)abstract
- Five different low-Mach large eddy simulations are compared to the turbulent stratified flame experiments conducted at the Technical University of Darmstadt (TUD). The simulations were contributed by TUD, the Institute for Combustion Technology (ITV) at Aachen, Lund University (LUND), the EM2C laboratory at Ecole Centrale Paris, and the University of Duisburg-Essen (UDE). Combustion is modeled by a premixed flamelet tabulation with local flame thickening (TUD), a premixed flamelet progress variable approach coupled to a level set method (ITV), a 4-steps mechanism combined with implicit LES (LUND), the F-TACLES model that is based on filtered premixed flamelet tabulation (EM2C), and a flame surface density approach (UDE). An extensive comparison of simulation and experimental data is presented for the first two moments of velocity, temperature, mixture fraction, and major species mass fractions. The importance of heat-losses was assessed by comparing simulations for adiabatic and isothermal boundary conditions at the burner walls. The adiabatic computations predict a flame anchored on the burner lip, while the non-adiabatic simulations show a flame lift-off of one half pilot diameter and a better agreement with experimental evidence for temperature and species concentrations. Most simulations agree on the mean flame brush position, but it is evident that subgrid turbulence must be considered to achieve the correct turbulent flame speed. Qualitative comparisons of instantaneous snapshots of the flame show differences in the size of the resolved flame wrinkling patterns. These differences are (a) caused by the influence of the LES combustion model on the flame dynamics and (b) by the different simulation strategies in terms of grid, inlet condition and numerics. The simulations were conducted with approaches optimized for different objectives, for example low computational cost, or in another case, short turn around. (C) 2015 The Combustion Institute. Published by Elsevier Inc. All rights reserved.
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- Martinello, K. A., et al.
(author)
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Acute LPS sensitization and continuous infusion exacerbates hypoxic brain injury in a piglet model of neonatal encephalopathy
- 2019
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In: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 9:1
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Journal article (peer-reviewed)abstract
- Co-existing infection/inflammation and birth asphyxia potentiate the risk of developing neonatal encephalopathy (NE) and adverse outcome. In a newborn piglet model we assessed the effect of E. coli lipopolysaccharide (LPS) infusion started 4 h prior to and continued for 48 h after hypoxia on brain cell death and systemic haematological changes compared to LPS and hypoxia alone. LPS sensitized hypoxia resulted in an increase in mortality and in brain cell death (TUNEL positive cells) throughout the whole brain, and in the internal capsule, periventricular white matter and sensorimotor cortex. LPS alone did not increase brain cell death at 48 h, despite evidence of neuroinflammation, including the greatest increases in microglial proliferation, reactive astrocytosis and cleavage of caspase-3. LPS exposure caused splenic hypertrophy and platelet count suppression. The combination of LPS and hypoxia resulted in the highest and most sustained systemic white cell count increase. These findings highlight the significant contribution of acute inflammation sensitization prior to an asphyxial insult on NE illness severity.
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