83 research outputs found
Interval Fuzzy Model for Robust Aircraft IMU Sensors Fault Detection
This paper proposes a data-based approach for a robust fault detection (FD) of the inertial measurement unit (IMU) sensors of an aircraft. Fuzzy interval models (FIMs) have been introduced for coping with the significant modeling uncertainties caused by poorly modeled aerodynamics. The proposed FIMs are used to compute robust prediction intervals for the measurements provided by the IMU sensors. Specifically, a nonlinear neural network (NN) model is used as central prediction of the sensor response while the uncertainty around the central estimation is captured by the FIM model. The uncertainty has been also modelled using a conventional linear Interval Model (IM) approach; this allows a quantitative evaluation of the benefits provided by the FIM approach. The identification of the IMs and of the FIMs was formalized as a linear matrix inequality (LMI) optimization problem using as cost function the (mean) amplitude of the prediction interval and as optimization variables the parameters defining the amplitudes of the intervals of the IMs and FIMs. Based on the identified models, FD validation tests have been successfully conducted using actual flight data of a P92 Tecnam aircraft by artificially injecting additive fault signals on the fault free IMU readings
Air Data Sensor Fault Detection with an Augmented Floating Limiter
Although very uncommon, the sequential failures of all aircraft Pitot tubes, with the consequent loss of signals for all the dynamic parameters from the Air Data System, have been found to be the cause of a number of catastrophic accidents in aviation history. This paper proposes a robust data-driven method to detect faulty measurements of aircraft airspeed, angle of attack, and angle of sideslip. This approach first consists in the appropriate selection of suitable sets of model regressors to be used as inputs of neural network-based estimators to be used online for failure detection. The setup of the proposed fault detection method is based on the statistical analysis of the residual signals in fault-free conditions, which, in turn, allows the tuning of a pair of floating limiter detectors that act as time-varying fault detection thresholds with the objective of reducing both the false alarm rate and the detection delay. The proposed approach has been validated using real flight data by injecting artificial ramp and hard failures on the above sensors. The results confirm the capabilities of the proposed scheme showing accurate detection with a desirable low level of false alarm when compared with an equivalent scheme with conventional “a priori set” fixed detection thresholds. The achieved performance improvement consists mainly in a substantial reduction of the detection time while keeping desirable low false alarm rates
Influence of Dietary Supplementation with Prebiotic, Oregano Extract, and Vitamin E on Fatty Acid Profile and Oxidative Status of Rabbit Meat
The effect of dietary supplementation with vitamin E, oregano, and prebiotic on fatty acids and oxidative profiles of rabbit meat (loin and hind leg) was evaluated. New Zealand white rabbits weaned at 30 days of age were fed with one of six diets until 80 days of age: standard diet includingω3 polyunsaturated fatty and conjugated linolenic acids sources (S) and five diets adding vitamin E (150 ppm, E), oregano water extract (2 g/kg feed diet, O), prebiotic (THEPAX® 1.5 g/kg feed diet, T), vitamin E plus prebiotic (TE), and oregano water extract plus prebiotic (TO), respectively. The lipid oxidative status (TBARS) showed lower values with respect to S, mainly when vitamin E was administered. In particular, all the experimental diets decreased TBARS values with respect to the control group in the loin, but no effect was found in the hind leg. In all feed samples, the amounts of fatty acid classes increased in the following order: polyunsaturated fatty acids > monounsaturated fatty acid > saturated fatty acid. The dietary supplementations did not affect the fatty acid composition of meat. The experimented diets compared to the control were not able to provide a selective increase of bioactive fatty acid in meat samples; however, the six nutritional strategies led to highly nutritional rabbit meat with an interesting value of theω6/ω3 ratio
Spent espresso coffee grounds as a source of anti-proliferative and antioxidant compounds
Disposal of spent espresso coffee grounds (SCG) is costly and leads to the loss of bioactive compounds that could be fractionated, in several applications. This work aimed to investigate phenolic profile, tocopherols, and antioxidant and anti-proliferative activities of SCGs ethanolic extracts from coffee powders differing in coffee provenience and composition (arabica/robusta). Tyrosol, detected for the first time in SCGs, was the most abundant phenolic measured (121-1,084 mg/kg in the extract), along with 4-hydroxybenzoic acid and vanillin (885-1813 and 340-1103 mg/kg, respectively). Extract derived from 100% robusta from Guatemala (S7-R) showed the highest α- to ß-tocopherol ratio of 1.2 and the highest antioxidant potential as evidenced by RACI and GAS values of -0.43 and 0.20, respectively. Moreover, S7-R showed a promising anti-proliferative activity toward human lung carcinoma cells (A549), with IC50 value of 61.2 ug/mL comparable to that given by the positive control vinblastine (IC50 value of 67.3 ug/mL)
Clinical and Translational Results of a Phase II Randomized Trial of Maintenance Sunitinib or Observation in Metastatic Pancreatic Adenocarcinoma
Context To prolong chemotherapy over 6 months in metastatic pancreatic adenocarcinoma (MPA) has unproven benefit and is hampered by cumulative toxicity. Objective This phase II trial explored the role of maintenance sunitinib (MS), using an observation (O) group as calibration arm. The predictive role of circulating endothelial cells (CEC) and of functional polymorphisms (SNPs) of genes involved in sunitinib activity, metabolism and transport (VEGFA, VEGFR-2, CYP3A5, CYP1A1, ABCB1, ABCG2) was explored. Methods Patients with pathologic diagnosis of MPA, PS >50%, no PD after 6 months of chemotherapy were randomized to O (arm A) or MS (37.5 mg daily) for 6 months (arm B). Primary endpoint was PFS-6. The target enrolment was 26 patients among whom >5 PFS-6 were necessary to declare MS of interest. CEC and SNPs were evaluated on baseline blood samples. Results Twenty-eight patients were assigned arm A and 28 arm B, one of whom was ineligible (kidney cancer). Baseline characteristics were balanced; previous chemotherapy was (A/B): gemcitabine 2/3; combination chemotherapy 25/25. Median duration of MS was 2.8 months. Grade 3-4 toxicity (arm B) was 15% neutropenia; 12% thrombocytopenia and hand-foot syndrome, 8% diarrhea. PFS-6 was 4% and 22%; median PFS was 2.0 and 3.2 months (P=0.01); 2-year OS was 5% and 22% (P=0.12). CEC analysis (n=46; 84%) showed a longer median PFS in untreated patients with CEC <30 when compared to >30 (2.9 versus 1.9 months; P=0.08); a significantly increased PFS in patients with CEC >30 treated by MS versus O (3.4 months; P=0.02); no PFS difference between arms in patients with CEC <30. Genotyping analysis (n=43; 78%) showed a longer median OS among arm B patients with ABCB1 3435TT genotype as compared to 3435CC/CT genotype (26 versus 7 months; P=0.11); and with VEGFA -634GC-CC genotype as compared to -634GG genotype (11 versus 6 months; P=0.013). Conclusions MS fulfilled the primary endpoint of the trial and yielded remarkable OS figures. CEC and SNPs may be useful to predict benefit from MS
Bicuculline Reduces Neuroinflammation in Hippocampus and Improves Spatial Learning and Anxiety in Hyperammonemic Rats. Role of Glutamate Receptors
Patients with liver cirrhosis may develop minimal hepatic encephalopathy (MHE) with mild cognitive impairment. Hyperammonemia is a main contributor to cognitive impairment in MHE, which is mediated by neuroinflammation. GABAergic neurotransmission is altered in hyperammonemic rats. We hypothesized that, in hyperammonemic rats, (a) enhanced GABAergic tone would contribute to induce neuroinflammation, which would be improved by reducing GABAergic tone by chronic bicuculline treatment; (b) this would improve spatial learning and memory impairment; and (c) modulation of glutamatergic neurotransmission would mediate this cognitive improvement. The aim of this work was to assess the above hypotheses. Bicuculline was administrated intraperitoneally once a day for 4 weeks to control and hyperammonemic rats. The effects of bicuculline on microglia and astrocyte activation, IL-1β content, on membrane expression of AMPA and NMDA glutamate receptors subunits in the hippocampus and on spatial learning and memory as well as anxiety were assessed. Treatment with bicuculline reduces astrocyte activation and IL-1β but not microglia activation in the hippocampus of hyperammonemic rats. Bicuculline reverses the changes in membrane expression of AMPA receptor subunits GluA1 and GluA2 and of the NR2B (but not NR1 and NR2A) subunit of NMDA receptors. Bicuculline improves spatial learning and working memory and decreases anxiety in hyperammonemic rats. In hyperammonemia, enhanced activation of GABAA receptors in the hippocampus contributes to some but not all aspects of neuroinflammation, to altered glutamatergic neurotransmission and to impairment of spatial learning and memory as well as anxiety, all of which are reversed by reducing activation of GABAA receptors with bicuculline
REDISCOVER International Guidelines on the Perioperative Care of Surgical Patients With Borderline-resectable and Locally Advanced Pancreatic Cancer
OBJECTIVE: The REDISCOVER consensus conference aimed at developing and validate guidelines on the perioperative care of patients with borderline resectable (BR-) and locally advanced (LA) pancreatic ductal adenocarcinoma (PDAC).SUMMARY BACKGROUND DATA: Coupled with improvements in chemotherapy and radiation, the contemporary approach to pancreatic surgery supports resection of BR-PDAC and, to a lesser extent, LA-PDAC. Guidelines outlining the selection and perioperative care for these patients are lacking.METHODS: The Scottish Intercollegiate Guidelines Network (SIGN) methodology was used to develop the REDISCOVER guidelines and create recommendations. The Delphi approach was used to reach consensus (agreement ≥80%) among experts. Recommendations were approved after a debate and vote among international experts in pancreatic surgery and pancreatic cancer management. A Validation Committee used the AGREE II-GRS tool to assess the methodological quality of the guidelines. Moreover, an independent multidisciplinary advisory group revised the statements to ensure adherence to non-surgical guidelines.RESULTS: Overall, 34 recommendations were created targeting centralization, training, staging, patient selection for surgery, possibility of surgery in uncommon scenarios, timing of surgery, avoidance of vascular reconstruction, details of vascular resection/reconstruction, arterial divestment, frozen section histology of perivascular tissue, extent of lymphadenectomy, anticoagulation prophylaxis and role of minimally invasive surgery. The level of evidence was however low for 29 of 34 clinical questions. Participants agreed that the most conducive mean to promptly advance our understanding in this field is to establish an international registry addressing this patient population ( https://rediscover.unipi.it/ ).CONCLUSIONS: The REDISCOVER guidelines provide clinical recommendations pertaining to pancreatectomy with vascular resection for patients with BR- and LA-PDAC, and serve as the basis of a new international registry for this patient population.</p
REDISCOVER International Guidelines on the Perioperative Care of Surgical Patients With Borderline-resectable and Locally Advanced Pancreatic Cancer
OBJECTIVE: The REDISCOVER consensus conference aimed at developing and validate guidelines on the perioperative care of patients with borderline resectable (BR-) and locally advanced (LA) pancreatic ductal adenocarcinoma (PDAC).SUMMARY BACKGROUND DATA: Coupled with improvements in chemotherapy and radiation, the contemporary approach to pancreatic surgery supports resection of BR-PDAC and, to a lesser extent, LA-PDAC. Guidelines outlining the selection and perioperative care for these patients are lacking.METHODS: The Scottish Intercollegiate Guidelines Network (SIGN) methodology was used to develop the REDISCOVER guidelines and create recommendations. The Delphi approach was used to reach consensus (agreement ≥80%) among experts. Recommendations were approved after a debate and vote among international experts in pancreatic surgery and pancreatic cancer management. A Validation Committee used the AGREE II-GRS tool to assess the methodological quality of the guidelines. Moreover, an independent multidisciplinary advisory group revised the statements to ensure adherence to non-surgical guidelines.RESULTS: Overall, 34 recommendations were created targeting centralization, training, staging, patient selection for surgery, possibility of surgery in uncommon scenarios, timing of surgery, avoidance of vascular reconstruction, details of vascular resection/reconstruction, arterial divestment, frozen section histology of perivascular tissue, extent of lymphadenectomy, anticoagulation prophylaxis and role of minimally invasive surgery. The level of evidence was however low for 29 of 34 clinical questions. Participants agreed that the most conducive mean to promptly advance our understanding in this field is to establish an international registry addressing this patient population ( https://rediscover.unipi.it/ ).CONCLUSIONS: The REDISCOVER guidelines provide clinical recommendations pertaining to pancreatectomy with vascular resection for patients with BR- and LA-PDAC, and serve as the basis of a new international registry for this patient population.</p
Surgical and Oncological Outcomes After Preoperative FOLFIRINOX Chemotherapy in Resected Pancreatic Cancer : An International Multicenter Cohort Study
Background. Preoperative FOLFIRINOX chemotherapy is increasingly administered to patients with borderline resectable (BRPC) and locally advanced pancreatic cancer (LAPC) to improve overall survival (OS). Multicenter studies reporting on the impact from the number of preoperative cycles and the use of adjuvant chemotherapy in relation to outcomes in this setting are lacking. This study aimed to assess the outcome of pancreatectomy after preoperative FOLFIRINOX, including predictors of OS.Methods. This international multicenter retrospective cohort study included patients from 31 centers in 19 European countries and the United States undergoing pancreatectomy after preoperative FOLFIRINOX chemotherapy (2012-2016). The primary end point was OS from diagnosis. Survival was assessed using Kaplan-Meier analysis and Cox regression.Results. The study included 423 patients who underwent pancreatectomy after a median of six (IQR 5-8) preoperative cycles of FOLFIRINOX. Postoperative major morbidity occurred for 88 (20.8%) patients and 90-day mortality for 12 (2.8%) patients. An R0 resection was achieved for 243 (57.4%) patients, and 259 (61.2%) patients received adjuvant chemotherapy. The median OS was 38 months (95% confidence interval [CI] 34-42 months) for BRPC and 33 months (95% CI 27-45 months) for LAPC. Overall survival was significantly associated with R0 resection (hazard ratio [HR] 1.63; 95% CI 1.20-2.20) and tumor differentiation (HR 1.43; 95% CI 1.08-1.91). Neither the number of preoperative chemotherapy cycles nor the use adjuvant chemotherapy was associated with OS.Conclusions. This international multicenter study found that pancreatectomy after FOLFIRINOX chemotherapy is associated with favorable outcomes for patients with BRPC and those with LAPC. Future studies should confirm that the number of neoadjuvant cycles and the use adjuvant chemotherapy have no relation to OS after resection.Peer reviewe
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