1,005 research outputs found
Aerostructural Wing Shape Optimization assisted by Algorithmic Differentiation
With more efficient structures, last trends in aeronautics have witnessed an
increased flexibility of wings, calling for adequate design and optimization
approaches. To correctly model the coupled physics, aerostructural optimization
has progressively become more important, being nowadays performed also
considering higher-fidelity discipline methods, i.e., CFD for aerodynamics and
FEM for structures. In this paper a methodology for high-fidelity
gradient-based aerostructural optimization of wings, including aerodynamic and
structural nonlinearities, is presented. The main key feature of the method is
its modularity: each discipline solver, independently employing algorithmic
differentiation for the evaluation of adjoint-based sensitivities, is
interfaced at high-level by means of a wrapper to both solve the aerostructural
primal problem and evaluate exact discrete gradients of the coupled problem.
The implemented capability, ad-hoc created to demonstrate the methodology, and
freely available within the open-source SU2 multiphysics suite, is applied to
perform aerostructural optimization of aeroelastic test cases based on the
ONERA M6 and NASA CRM wings. Single-point optimizations, employing Euler or
RANS flow models, are carried out to find wing optimal outer mold line in terms
of aerodynamic efficiency. Results remark the importance of taking into account
the aerostructural coupling when performing wing shape optimization
Soluble P-selectin levels in synovial fluid and serum from patients with psoriatic arthritis
Objective: P-selectin is an adhesion molecule expressed by activated endothelial cells and platelets favouring the leukocyte adherence to microvascular endothelium. A soluble form of this molecule has been described, whose serum levels were found to be elevated and correlate with disease activity in rheumatoid arthritis (RA) patients. Aim of this study was to determine soluble P-selectin levels in synovial fluid (SF) and serum from patients with psoriatic arthritis (PsA), where it has never been investigated, to define its involvement in PsA synovial damage. Methods: we analysed, by ELISA, soluble P-selectin serum and SF levels in 100 patients presenting a knee joint effusion: 38 of them presented PsA, 40 RA and 22 osteoarthritis (OA). We examined the main clinical and laboratory parameters of these patients. Soluble P-selectin serum levels were also detected in 15 healthy subjects. Results: soluble P-selectin SF levels were significantly higher in PsA and RA patients respect to OA subjects. Soluble P-selectin SF levels were lower than those found in serum and the SF/serum ratio was higher in PsA and RA patients respect to OA. Soluble P-selectin serum levels were not significantly different among patients and controls. No correlation was found between SF and serum levels of soluble P-selectin and the main clinical parameters. Conclusions: our study of soluble P-selectin in PsA reveals a prominent local role of this molecule, with no differences respect to RA. Histological findings may be of help in understanding the role of this adhesion molecule in PsA
Adverse events during longterm low-dose glucocorticoid treatment of polymyalgia rheumatica: a retrospective study
To assess the occurrence of adverse events in a cohort of patients with polymyalgia rheumatica (PMR), treated with low-dose glucocorticoids (GC).
METHODS:
This was a retrospective study by review of medical records.
RESULTS:
We identified 222 patients who had a mean duration of followup of 60 ± 22 months and a mean duration of GC therapy of 46 ± 22 months. We found that 95 patients (43%) had at least 1 adverse event after a mean duration of GC therapy of 31 ± 22 months and a mean cumulative dose of 3.4 ± 2.4 g. In particular, 55 developed osteoporosis, 31 had fragility fractures; 27 developed arterial hypertension; 11 diabetes mellitus; 9 acute myocardial infarction; 3 stroke; and 2 peripheral arterial disease. Univariate analysis showed that the duration of GC treatment was significantly associated with osteoporosis (p < 0.0001), fragility fractures (p < 0.0001), arterial hypertension (p < 0.005), and acute myocardial infarction (p < 0.05). Cumulative GC dose was significantly associated with osteoporosis (p < 0.0001), fragility fractures (p < 0.0001), and arterial hypertension (p < 0.01). The adverse events occurred more frequently after 2 years of treatment. Multivariate analysis showed that GC duration was significantly associated with osteoporosis (adjusted OR 1.02, 95% CI 1.02-1.05) and arterial hypertension (adjusted OR 1.03, 95% CI 1.01-1.06); GC cumulative dose was significantly associated with fragility fractures (adjusted OR 1.4, 95% CI 1.03-1.8).
CONCLUSION:
Longterm, low-dose GC treatment of PMR is associated with serious adverse events such as osteoporosis, fractures, and arterial hypertension; these adverse events occur mostly after 2 years of treatment
Relativistic Proton Production During the 14 July 2000 Solar Event: The Case for Multiple Source Mechanisms
Protons accelerated to relativistic energies by transient solar and
interplanetary phenomena caused a ground-level cosmic ray enhancement on 14
July 2000, Bastille Day. Near-Earth spacecraft measured the proton flux
directly and ground-based observatories measured the secondary responses to
higher energy protons. We have modelled the arrival of these relativistic
protons at Earth using a technique which deduces the spectrum, arrival
direction and anisotropy of the high-energy protons that produce increased
responses in neutron monitors. To investigate the acceleration processes
involved we have employed theoretical shock and stochastic acceleration
spectral forms in our fits to spacecraft and neutron monitor data. During the
rising phase of the event (10:45 UT and 10:50 UT) we find that the spectrum
between 140 MeV and 4 GeV is best fitted by a shock acceleration spectrum. In
contrast, the spectrum at the peak (10:55 UT and 11:00 UT) and in the declining
phase (11:40 UT) is best fitted with a stochastic acceleration spectrum. We
propose that at least two acceleration processes were responsible for the
production of relativistic protons during the Bastille Day solar event: (1)
protons were accelerated to relativistic energies by a shock, presumably a
coronal mass ejection (CME). (2) protons were also accelerated to relativistic
energies by stochastic processes initiated by magnetohydrodynamic (MHD)
turbulence.Comment: 38 pages, 9 figures, accepted for publication in the Astrophysical
Journal, January, 200
Churg-Strauss syndrome: outcome and long-term follow-up of 38 patients from a single Italian centre
Objective: This study was aimed at verifying any potential correlation between anti-myeloperoxidase antineutrophil cytoplasmic antibodies (ANCA-MPO) and clinical features and outcome indices in Churg-Strauss Syndrome (CSS). Methods: Thirhty-eight Churg-Strauss syndrome patients were selected from the medical records of all vasculitis patients attending the Rheumatology and Immunology Unit at the Department of Internal Medicine of the University of Pisa in the decades between 1989 and 2008. Data were analysed retrospectively. Statistical analyses of the results were carried out using the Mann-Whitney test to determine the correlations between the clinical and serological parameters. Qualitative variables were compared using contingency table analysis and Fisher's exact test. Results: ANCA-MPO were detected in15/38 (39%) patients. Positive ANCA status was associated with peripheral neuropathy (p=0.0006), whereas negative ANCA status was associated with lung involvement (p=0.002). Relapses were strongly associated with positive ANCA status (p=0.01) and with an increase in- or a reappearence of ANCA-MPO levels (p=0.006). Finally, ANCA-MPO were significantly associated with neurological damage (p=0.003). Conclusions: The presence or absence of ANCA-MPO identify different clinical subsets in CSS. Overall, ANCA-MPO appears as a useful tool in the monitoring of CSS and in particular a good predictor of CSS relapse
Anthropometric evaluation and micronutrients intake in patients submitted to laparoscopic Roux-en-Y gastric bypass with a postoperative period of ≥1 year
Backgroung - Bariatric surgery is indicated as the most effective treatment for morbid obesity; the Roux-en-Y gastric bypass (RYGB) is considered the procedure of choice. However, nutritional deficiency may occur in the postoperative period as a result of reduced gastric capacity and change in nutrients absorption in the gastrointestinal tract. The prescription of vitamin and mineral supplementation is a common practice after RYGB; however, it may not be sufficient to prevent micronutrient deficiencies. The aim of this study was to quantify the micronutrient intake in patients undergoing RYGB and verify if the intake of supplementation would be enough to prevent nutritional deficiencies. Methods - The study was conducted on 60 patients submitted to RYGB. Anthropometric, analytical, and nutritional intake data were assessed preoperatively and 1 and 2 years postoperatively. The dietary intake was assessed using 24-h food recall; the values of micronutrients evaluated (vitamin B12, folic acid, iron, and calcium) were compared to the dietary reference intakes (DRI). Results - There were significant differences (p < 0.05) between excess weight loss at the first and second year (69.9 ± 15.3 vs 9.6 ± 62.9 %). In the first and second year after surgery, 93.3 and 94.1 % of the patients, respectively, took the supplements as prescribed. Micronutrient deficiencies were detected in the three evaluation periods. At the first year, there was a significant reduction (p < 0.05) of B12, folic acid, and iron intake. Conclusions - Despite taking vitamin and mineral supplementation, micronutrient deficiencies are common after RYGB. In the second year after surgery, micronutrient intake remains below the DRI
CXCL13, CCL21, and CXCL12 expression in salivary glands of patients with Sjogren's syndrome and MALT lymphoma: Association with reactive and malignant areas of lymphoid organization
The chemokines (CKs) CXCL13, CCL21, and CXCL12 are known to play differential roles in the organization of the lymphoid tissues and the development of lymphoid malignancies. We investigated the expression of these CKs and their receptors in the salivary glands of Sjogren's syndrome patients with lymphoepithelial lesions (lymphoepithelial sialadenitis or LESA) and in MALT lymphoma to understand their involvement in salivary gland lymphomagenesis. We demonstrate that within salivary glands with LESA and MALT lymphoma the lymphoid CKs CXCL13 and CCL21 are selectively associated with areas of reactive lymphoid proliferation, whereas no significant expression of these molecules was detected in the malignant lymphoid aggregate. Conversely, CXCL12 was observed predominantly in infiltrated ducts and malignant B cells. Accordingly, CXCL13 and CCL21 transcript levels were significantly increased in LESA samples while CXCL12 levels were increased in MALT lymphoma and isolated tumor cells. Low levels of CK receptors were detected on lymphoma-extracted lymphocytes, suggesting down-regulation in the abundance of ligands. Our findings suggest that in salivary gland MALT lymphoma the lymphoid CKs CXCL13 and CCL21 are directly implicated in the organization of ectopic reactive lymphoid tissue, whereas CXCL12 is associated with the infiltrated epithelium and malignant B cell component and is possibly involved in the regulation of malignant B cell survival
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