Flatness-based fault tolerant control

Este artículo presenta un método de control tolerante a fallas para sistemas no lineales planos. Las propiedades intrínsecas de los sistemas planos generan redundancia analítica y permiten calcular todos los estados y las entradas de control del sistema. Los residuos son calculados comparando las medidas reales provenientes de los sensores y las señales obtenidas gracias al conjunto de ecuaciones del sistema plano. Fallas multiplicativas y aditivas se pueden manejar de manera indistinta. Las señales redundantes obtenidas con las ecuaciones del sistema plano son usadas para reconfigurar el sistema con falla. La factibilidad del método propuesto es verificada para fallas aditivas en un sistema de tres tanques. ABSTRACT This paper presents a Fault Tolerant control approach for nonlinear flat systems. Flatness property affords analytical redundancy and permit to compute the states and control inputs of the system. Residual signals are computed by comparing real measures and the computed signals obtained using the differentially flat equations. Multiplicative and additive faults can be handled indistinctly. The redundant signals obtained with the differentially flat equations are used to reconfigure the faulty system. Feasibility of this approach is verified for additive faults in a three tank system

Efficacy of Biological-Targeted Treatments in Takayasu Arteritis

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Impact of aging on phenotype and prognosis in IgA vasculitis

International audienceObjectives Immunoglobulin A vasculitis (IgAV) is a small-vessel vasculitis most frequently benign in children while more severe in adults. We aimed to study the impact of age on presentation and outcome of adult IgAV. Methods We conducted a nationwide retrospective study including 260 IgAV patients. Patients were divided into four quartiles according to the age at IgAV diagnosis: <36, 36 ≤ age < 52; 52 ≤ age < 63 and ≥63 years. Comparison of presentation and outcome were performed according to age of disease onset. Results Mean age at diagnosis was 50.1 (18) years and 63% were male. IgAV diagnosed in the lowest quartile of age was associated with more frequent joint (P < 0.0001) and gastrointestinal involvement (P = 0.001). In contrast, the oldest patients had more severe purpura with necrotic lesions (P = 0.001) and more frequent renal involvement (P < 0.0001), with more frequent haematuria, renal failure, higher urine protein excretion and more frequent tubulointerstitial lesions. Patients were treated similarly in all groups of age, and clinical response and relapse rates were similar between groups. In the 127 treated patients with follow-up data for >6 months, clinical response and relapse rates were similar between the four groups. Median follow-up was of 17.2 months (9.1–38.3 months). Renal failure at the end of follow-up was significantly more frequent in the highest quartile of age (P = 0.02), but the occurrence of end-stage renal disease was similar in all groups. Last, overall and IgAV-related deaths were associated with increase in age. Conclusion Aging negatively impacts the severity and outcome of IgAV in adults. Younger patients have more frequent joint and gastrointestinal involvement, while old patients display more frequent severe purpura and glomerulonephritis

Characterisation of a high-risk profile for maternal thrombotic and severe haemorrhagic complications in pregnant women with antiphospholipid syndrome in France (GR2): a multicentre, prospective, observational study

International audienceBackgroundProspective data about the risks of thrombotic and severe haemorrhagic complications during pregnancy and post partum are unavailable for women with antiphospholipid syndrome. We aimed to assess thrombotic and haemorrhagic events in a prospective cohort of pregnant women with antiphospholipid syndrome.MethodsThis multicentre, prospective, observational study was done at 76 centres in France. To be eligible for this study, women had to have diagnosis of antiphospholipid syndrome; have conceived before April 17, 2020; have an ongoing pregnancy that had reached 12 weeks of gestation; and be included in the study before 18 weeks of gestation. Exclusion criteria were active systemic lupus erythematosus nephropathy, or a multifetal pregnancy. Severe haemorrhage was defined as the need for red blood cell transfusion or maternal intensive care unit admission because of bleeding or invasive procedures, defined as interventional radiology or surgery, to control bleeding. The GR2 study is registered with ClinicalTrials.gov, NCT02450396.FindingsBetween May 26, 2014, and April 17, 2020, 168 pregnancies in 27 centres met the inclusion criteria for the study. 89 (53%) of 168 women had a history of thrombosis. The median term at inclusion was 8 weeks gestation. 16 (10%) of 168 women (95%CI 5–15) had a thrombotic (six [4%] women; 95% CI 1–8) or severe haemorrhagic event (12 [7%] women; 95% CI 4–12). There were no deaths during the study. The main risk factors for thrombotic events were lupus anticoagulant positivity at inclusion (six [100%] of six women with thrombosis vs 78 [51%] of 152 of those with no thrombosis; p=0·030) and placental insufficiency (four [67%] of six women vs 28 [17%] of 162 women; p=0·013). The main risk factors for severe haemorrhagic events were pre-existing maternal hypertension (four [33%] of 12 women vs 11 [7%] of 156 women; p=0·014), lupus anticoagulant positivity at inclusion (12 [100%] of 12 women vs 72 [49%] of 146 women; p<0·0001) and during antiphospholipid history (12 [100%] of 12 women vs 104 [67%] of 156 women; p=0·019), triple antiphospholipid antibody positivity (eight [67%] of 12 women vs 36 [24%] of 147 women; p=0·0040), placental insufficiency (five [42%] of 12 women vs 27 [17%] of 156 women; p=0·038), and preterm delivery at 34 weeks or earlier (five [45%] of 11 women vs 12 [8%] of 145 women; p=0·0030).InterpretationDespite treatment adhering to international recommendations, a proportion of women with antiphospholipid syndrome developed a thrombotic or severe haemorrhagic complication related to pregnancy, most frequently in the post-partum period. Lupus anticoagulant and placental insufficiency were risk factors for these life-threatening complications. These complications are difficult to prevent, but knowledge of the antenatal characteristics associated with them should increase awareness and help physicians manage these high-risk pregnancies

Long-term safety and efficacy of patisiran for hereditary transthyretin-mediated amyloidosis with polyneuropathy: 12-month results of an open-label extension study

© 2020 Elsevier Ltd. All rights reserved.Background: Hereditary transthyretin-mediated amyloidosis is a rare, inherited, progressive disease caused by mutations in the transthyretin (TTR) gene. We assessed the safety and efficacy of long-term treatment with patisiran, an RNA interference therapeutic that inhibits TTR production, in patients with hereditary transthyretin-mediated amyloidosis with polyneuropathy. Methods: This multicentre, open-label extension (OLE) trial enrolled patients at 43 hospitals or clinical centres in 19 countries as of Sept 24, 2018. Patients were eligible if they had completed the phase 3 APOLLO or phase 2 OLE parent studies and tolerated the study drug. Eligible patients from APOLLO (patisiran and placebo groups) and the phase 2 OLE (patisiran group) studies enrolled in this global OLE trial and received patisiran 0·3 mg/kg by intravenous infusion every 3 weeks with plans to continue to do so for up to 5 years. Efficacy assessments included measures of polyneuropathy (modified Neuropathy Impairment Score +7 [mNIS+7]), quality of life, autonomic symptoms, nutritional status, disability, ambulation status, motor function, and cardiac stress, with analysis by study groups (APOLLO-placebo, APOLLO-patisiran, phase 2 OLE patisiran) based on allocation in the parent trial. The global OLE is ongoing with no new enrolment, and current findings are based on the interim analysis of the patients who had completed 12-month efficacy assessments as of the data cutoff. Safety analyses included all patients who received one or more dose of patisiran up to the data cutoff. This study is registered with ClinicalTrials.gov, NCT02510261. Findings: Between July 13, 2015, and Aug 21, 2017, of 212 eligible patients, 211 were enrolled: 137 patients from the APOLLO-patisiran group, 49 from the APOLLO-placebo group, and 25 from the phase 2 OLE patisiran group. At the data cutoff on Sept 24, 2018, 126 (92%) of 137 patients from the APOLLO-patisiran group, 38 (78%) of 49 from the APOLLO-placebo group, and 25 (100%) of 25 from the phase 2 OLE patisiran group had completed 12-month assessments. At 12 months, improvements in mNIS+7 with patisiran were sustained from parent study baseline with treatment in the global OLE (APOLLO-patisiran mean change -4·0, 95 % CI -7·7 to -0·3; phase 2 OLE patisiran -4·7, -11·9 to 2·4). Mean mNIS+7 score improved from global OLE enrolment in the APOLLO-placebo group (mean change from global OLE enrolment -1·4, 95% CI -6·2 to 3·5). Overall, 204 (97%) of 211 patients reported adverse events, 82 (39%) reported serious adverse events, and there were 23 (11%) deaths. Serious adverse events were more frequent in the APOLLO-placebo group (28 [57%] of 49) than in the APOLLO-patisiran (48 [35%] of 137) or phase 2 OLE patisiran (six [24%] of 25) groups. The most common treatment-related adverse event was mild or moderate infusion-related reactions. The frequency of deaths in the global OLE was higher in the APOLLO-placebo group (13 [27%] of 49), who had a higher disease burden than the APOLLO-patisiran (ten [7%] of 137) and phase 2 OLE patisiran (0 of 25) groups. Interpretation: In this interim 12-month analysis of the ongoing global OLE study, patisiran appeared to maintain efficacy with an acceptable safety profile in patients with hereditary transthyretin-mediated amyloidosis with polyneuropathy. Continued long-term follow-up will be important for the overall assessment of safety and efficacy with patisiran.info:eu-repo/semantics/publishedVersio