653 research outputs found

    An entropy-based approach for a robust least squares spline approximation

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    We consider the weighted least squares spline approximation of a noisy dataset. By interpreting the weights as a probability distribution, we maximize the associated entropy subject to the constraint that the mean squared error is prescribed to a desired (small) value. Acting on this error yields a robust regression method that automatically detects and removes outliers from the data during the fitting procedure, by assigning them a very small weight. We discuss the use of both spline functions and spline curves. A number of numerical illustrations have been included to disclose the potentialities of the maximal-entropy approach in different application fields.Comment: 11 color picture

    MFI vs. FER zeolite during methanol dehydration to dimethyl ether: The crystal size plays a key role

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    Abstract FER-type zeolite was recently recognized as good catalyst for DME synthesis via methanol dehydration or one-pot CO2 hydrogenation, in terms of DME selectivity, stability and coke formation. In this research, we investigated the role of crystal size of both FER- and MFI-type zeolites on catalysis of methanol dehydration to DME reaction. The results show that FER-type zeolites, both micro- and nano-sized, exhibit better performances than micro-sized MFI-type zeolite. On the contrary, the application of nano-sized MFI allows to obtain a DME selectivity similar to FER, but with higher DME production rate and a lower coke deposition

    Circulating Endothelial Cell Levels Correlate with Treatment Outcomes of Splanchnic Vein Thrombosis in Patients with Chronic Myeloproliferative Neoplasms

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    Circulating endothelial cells (CECs) are viable, apoptotic or necrotic cells, identified by CD 146 surface antigen expression, considered a biomarker of thrombotic risk, given their active role in inflammatory, procoagulant and immune processes of the vascular compartment. Growing evidence establishes that CECs are also involved in the pathogenesis of several hematological and solid malignancies. The primary aim of this study was to verify if CEC levels could predict both the course and treatment responses of splanchnic vein thrombosis (SVT), either in patients affected by myeloproliferative neoplasms (MPNs) or liver disease. Thus, a retrospective multicenter study was performed; fifteen patients receiving anticoagulant oral treatment with vitamin k antagonists (VKA) for SVT were evaluated. Nine patients were affected by MPN, and all of them received cytoreduction in addition to anticoagulant therapy; four of these patients had primary myelofibrosis (PMF) and were treated with ruxolitinib (RUX), and one patient with primary myelofibrosis, two patients with essential thrombocythemia (ET), and two patients with polycythemia vera (PV) were treated with hydroxyurea (HU). Six patients affected by liver diseases (three with liver cirrhosis and three with hepatocellular carcinoma) were included as the control group. CECs were assayed by flow cytometry on peripheral blood at specific time points, for up to six months after enrollment. The CEC levels were related to C-reactive protein (CRP) levels, splenic volume reduction, and thrombus recanalization, mainly in MPN patients. In patients with liver cirrhosis (LC) and hepatocellular carcinoma (HCC), for which the mechanism of SVT development is quite different, the relationship between CEC and SV reduction was absent. In conclusion, the CEC levels showed a significant correlation with the extent of venous thrombosis and endothelial cell damage in myeloproliferative neoplasm patients with splanchnic vein thrombosis. Although preliminary, these results show how monitoring CEC levels during cytoreductive and anticoagulant treatments may be useful to improve SVT outcome in MPN patients

    Experimental setup to measure the heat-exchange processes by controlling thermal and hydraulic conditions

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    The design of a Borehole Heat Exchanger (BHE) is based on the evaluation of the thermal exchange capacity of the whole system constituted by the probes and the surrounding ground. The energy performance of a BHE mainly depends on the thermal properties of the sediments, the possible groundwater flow and the changes in the thermal gradient in the probe's surroundings due to the continuous heat exchange with the subsoil. The interpretation of the in-field applications is often difficult because in many instances the information needed is unavailable due to difficulties of in-field measurements. An experimental device was built in order to assess, under controlled conditions, the evolution in time and space of the energetic processes that occur between a thermal probe and the surrounding ground. A copper probe was placed into a soil control volume of 1m3 and 24 high precision temperature sensors were distributed inside this volume at different distances from the probe. The configuration of the experimental settings was built to allow alterations in terms of sediments, groundwater flow conditions, thermal probe properties and operations, in order to simulate different physical conditions and to better understand the complex physical processes involved. Another goal of the experimental research was to produce reliable experimental data that can be used for the calibration and set up of numerical models. This paper describes the experimental apparatus and two experiments performed in order to assess its capability to satisfy the design requirements

    Immune-Complexome Analysis Identifies Immunoglobulin-Bound Biomarkers That Predict the Response to Chemotherapy of Pancreatic Cancer Patients

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    Pancreatic Ductal Adenocarcinoma (PDA) is an aggressive malignancy with a very poor outcome. Although chemotherapy (CT) treatment has poor efficacy, it can enhance tumor immunogenicity. Tumor-Associated Antigens (TAA) are self-proteins that are overexpressed in tumors that may induce antibody production and can be PDA theranostic targets. However, the prognostic value of TAA-antibody association as Circulating Immune Complexes (CIC) has not yet been elucidated, mainly due to the lack of techniques that lead to their identification. In this study, we show a novel method to separate IgG, IgM, and IgA CIC from sera to use them as prognostic biomarkers of CT response. The PDA Immune-Complexome (IC) was identified using a LTQ-Orbitrap mass spectrometer followed by computational analysis. The analysis of the IC of 37 PDA patients before and after CT revealed differential associated antigens (DAA) for each immunoglobulin class. Our method identified different PDA-specific CIC in patients that were associated with poor prognosis patients. Finally, CIC levels were significantly modified by CT suggesting that they can be used as effective prognostic biomarkers to follow CT response in PDA patients
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