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- Glasbey, JC, et al.
(författare)
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- 2021
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swepub:Mat__t
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| 5. |
- Abiri, Olufunminiyi
(författare)
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Non-local models in manufacturing simulations
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Ductile fracture presents challenges with respect to material modelling andnumerical simulations of localization. The strain and damage localization maybe unwanted as it indicates a failure in the process or, as in the case ofmachining and cutting, a wanted phenomenon to be controlled. The latterrequires a higher accuracy regarding the modelling of the underlying coupledplastic and fracturing/damage behaviour of the material, metal in the currentcontext as well as the stability and robustness of the simulation procedure.This aim of this work is to develop, evaluate and implement formulations thatcan efficiently and reliably handle localization problems in machiningsimulations. The focus is on non-local models. The non-local models extendthe standard continuum mechanics theory by using non-local continuumtheory in order to achieve mesh independent results when simulating fractureor shear localization.The non-local damage model is implemented and various formulations areevaluated in a Matlab™ based finite element code. The chosen algorithm wasthen implemented in commercial software. The implementations remedy themesh sensitivity problem and gives convergent solution for metal cuttingsimulations with reasonable cost. The length scale associated with the nonlocalmodels are in the current context considered as a numericalregularization parameter. The model has been applied in machiningsimulations and compared with measurements from industry.Keywords: Finite element simulation; Non-local damage; Plasticity; Machining
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| 6. |
- Costa, Joao, et al.
(författare)
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The burden of atherosclerosis in Portugal
- 2021
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Ingår i: European Heart Journal - Quality of Care and Clinical Outcomes. - : Oxford University Press. - 2058-5225 .- 2058-1742. ; 7:2, s. 154-162
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Tidskriftsartikel (refereegranskat)abstract
- Aims This article sought to estimate the burden of disease attributable to atherosclerosis in mainland Portugal in 2016.Methods and results The burden of atherosclerosis was measured in disability-adjusted life years following the latest 2010 Global Burden of Disease (GBD) methodology. Disability-adjusted life years were estimated as the sum of years of life lost (YLL) with years lived with disability (YLD). The following clinical manifestations of atherosclerosis were included: ischaemic heart disease (IHD) (including acute myocardial infarction, stable angina, and ischaemic heart failure), ischaemic cerebrovascular disease (ICVD), and peripheral arterial disease (PAD). Years of life lost were estimated based on all-cause mortality data for the Portuguese population and mortality due to IHD, ICVD, and PAD for the year 2016 sourced from national statistics. Standard life expectancy was sourced from the GBD study. Years lived with disability corresponded to the product of the number of prevalent cases by an average disability weight for all possible combinations of disease. Prevalence data for the different clinical manifestations of atherosclerosis were sourced from epidemiological studies. Disability weights were sourced from the published literature. In 2016, 15123 deaths were attributable to atherosclerosis, which corresponded to 14.3% of overall mortality in mainland Portugal. Disability-adjusted life years totalled 260943, 75% due to premature death (196438 YLL) and 25% due to disability (64505 YLD).Conclusion Atherosclerosis entails a high disease burden to society. A large part of this burden would be avoidable if evidence-based effective and cost-effective interventions targeting known risk factors, from prevention to treatment, were implemented.
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| 7. |
- Farinha-Ferreira, Miguel, et al.
(författare)
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Unexpected short- and long-term effects of chronic adolescent HU-210 exposure on emotional behavior
- 2022
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Ingår i: Neuropharmacology. - : Elsevier. - 0028-3908 .- 1873-7064. ; 214
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Tidskriftsartikel (refereegranskat)abstract
- Chronic adolescent cannabinoid receptor agonist exposure has been shown to lead to persistent increases in depressive-like behaviors. This has been a key obstacle to the development of cannabinoid-based therapeutics. However, most of the published work has been performed with only three compounds, namely & UDelta;9-tetrahydro-cannabinol, CP55,940 and WIN55,212-2. Hypothesizing that different compounds may lead to distinct out-comes, we herein used the highly potent CB1R/CB2R full agonist HU-210, and first aimed at replicating cannabinoid-induced long-lasting effects, by exposing adolescent female Sprague-Dawley rats to increasing doses of HU-210, for 11 days and testing them at adulthood, after a 30-day drug washout. Surprisingly, HU-210 did not significantly impact adult anxious-or depressive-like behaviors. We then tested whether chronic adolescent HU -210 treatment resulted in short-term (24h) alterations in depressive-like behavior. Remarkably, HU-210 treat-ment simultaneously induced marked antidepressant-and prodepressant-like responses, in the modified forced swim (mFST) and sucrose preference tests (SPT), respectively. Hypothesizing that mFST results were a misleading artifact of HU-210-induced behavioral hyperreactivity to stress, we assessed plasmatic noradrenaline and corticosterone levels, under basal conditions and following an acute swim-stress episode. Notably, we found that while HU-210 did not alter basal noradrenaline or corticosterone levels, it greatly augmented the stress-induced increase in both. Our results show that, contrary to previously studied cannabinoid receptor agonists, HU-210 does not induce persisting depressive-like alterations, despite inducing marked short-term increases in stress-induced reactivity. By showing that not all cannabinoid receptor agonists may induce long-term negative effects, these results hold significant relevance for the development of cannabinoid-based therapeutics.
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| 8. |
- Khatri, C, et al.
(författare)
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Outcomes after perioperative SARS-CoV-2 infection in patients with proximal femoral fractures: an international cohort study
- 2021
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Ingår i: BMJ open. - : BMJ. - 2044-6055. ; 11:11, s. e050830-
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Tidskriftsartikel (refereegranskat)abstract
- Studies have demonstrated high rates of mortality in people with proximal femoral fracture and SARS-CoV-2, but there is limited published data on the factors that influence mortality for clinicians to make informed treatment decisions. This study aims to report the 30-day mortality associated with perioperative infection of patients undergoing surgery for proximal femoral fractures and to examine the factors that influence mortality in a multivariate analysis.SettingProspective, international, multicentre, observational cohort study.ParticipantsPatients undergoing any operation for a proximal femoral fracture from 1 February to 30 April 2020 and with perioperative SARS-CoV-2 infection (either 7 days prior or 30-day postoperative).Primary outcome30-day mortality. Multivariate modelling was performed to identify factors associated with 30-day mortality.ResultsThis study reports included 1063 patients from 174 hospitals in 19 countries. Overall 30-day mortality was 29.4% (313/1063). In an adjusted model, 30-day mortality was associated with male gender (OR 2.29, 95% CI 1.68 to 3.13, p<0.001), age >80 years (OR 1.60, 95% CI 1.1 to 2.31, p=0.013), preoperative diagnosis of dementia (OR 1.57, 95% CI 1.15 to 2.16, p=0.005), kidney disease (OR 1.73, 95% CI 1.18 to 2.55, p=0.005) and congestive heart failure (OR 1.62, 95% CI 1.06 to 2.48, p=0.025). Mortality at 30 days was lower in patients with a preoperative diagnosis of SARS-CoV-2 (OR 0.6, 95% CI 0.6 (0.42 to 0.85), p=0.004). There was no difference in mortality in patients with an increase to delay in surgery (p=0.220) or type of anaesthetic given (p=0.787).ConclusionsPatients undergoing surgery for a proximal femoral fracture with a perioperative infection of SARS-CoV-2 have a high rate of mortality. This study would support the need for providing these patients with individualised medical and anaesthetic care, including medical optimisation before theatre. Careful preoperative counselling is needed for those with a proximal femoral fracture and SARS-CoV-2, especially those in the highest risk groups.Trial registration numberNCT04323644
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| 9. |
- Otano, Itziar, et al.
(författare)
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CD137 (4-1BB) costimulation of CD8+ T cells is more potent when provided in cis than in trans with respect to CD3-TCR stimulation
- 2021
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- CD137 (4-1BB; TNFSR9) is an activation-induced surface receptor that through costimulation effects provide antigen-primed T cells with augmented survival, proliferation and effector functions as well as metabolic advantages. These immunobiological mechanisms are being utilised for cancer immunotherapy with agonist CD137-binding and crosslinking-inducing agents that elicit CD137 intracellular signaling. In this study, side-by-side comparisons show that provision of CD137 costimulation in-cis with regard to the TCR-CD3-ligating cell is superior to that provided in-trans in terms of T cell activation, proliferation, survival, cytokine secretion and mitochondrial fitness in mouse and human. Cis ligation of CD137 relative to the TCR-CD3 complex results in more intense canonical and non-canonical NF-κB signaling and provides a more robust induction of cell cycle and DNA damage repair gene expression programs. Here we report that the superiority of cis versus trans CD137-costimulation is readily observed in vivo and is relevant for understanding the immunotherapeutic effects of CAR T cells and CD137 agonistic therapies currently undergoing clinical trials, which may provide costimulation either in cis or in trans.
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| 10. |
- Vaz, Miguel, et al.
(författare)
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Modelling and simulation of machining processes
- 2007
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Ingår i: Archives of Computational Methods in Engineering. - : Springer Science and Business Media LLC. - 1134-3060 .- 1886-1784. ; 14:2, s. 173-204
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Tidskriftsartikel (refereegranskat)abstract
- The modelling of metal cutting has proved to be particularly complex due to the diversity of physical phenomena involved, including thermo-mechanical coupling, contact/friction and material failure. The present work outlines the wide range of complex physical phenomena involved in the chip formation in a descriptive manner. In order to improve and understand the process different numerical strategies have been used for simulation. Several of these numerical strategies are reviewed and a short discussion of their relative merits and drawbacks is presented. By means of several examples, where a combined experimental/numerical effort was undertaken, we try to illustrate what numerical techniques, models and pertinent parameters are needed for successful simulations.
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