141 research outputs found

    Accurate long-term air temperature prediction with Machine Learning models and data reduction techniques

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    In this paper, three customised Artificial Intelligence (AI) frameworks, considering Deep Learning, Machine Learning (ML) algorithms and data reduction techniques, are proposed for a problem of long-term summer air temperature prediction. Specifically, the prediction of the average air temperature in the first and second August fortnights, using input data from previous months, at two different locations (Paris, France) and (Córdoba, Spain), is considered. The target variable, mainly in the first August fortnight, can contain signals of extreme events such as heatwaves, like the heatwave of 2003, which affected France and the Iberian Peninsula. Three different computational frameworks for air temperature prediction are proposed: a Convolutional Neural Network (CNN), with video-to-image translation, several ML approaches including Lasso regression, Decision Trees and Random Forest, and finally a CNN with pre-processing step using Recurrence Plots, which convert time series into images. Using these frameworks, a very good prediction skill has been obtained in both Paris and Córdoba regions, showing that the proposed approaches can be an excellent option for seasonal climate prediction problems.This research has been partially supported by the European Union, through H2020 Project “CLIMATE INTELLIGENCE Extreme events detection, attribution and adaptation design using machine learning (CLINT)”, Ref: 101003876-CLINT. This research has also been partially supported by the project PID2020-115454GB-C21 of the Spanish Ministry of Science and Innovation (MICINN)

    Persistence in complex systems

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    Persistence is an important characteristic of many complex systems in nature, related to how long the system remains at a certain state before changing to a different one. The study of complex systems' persistence involves different definitions and uses different techniques, depending on whether short-term or long-term persistence is considered. In this paper we discuss the most important definitions, concepts, methods, literature and latest results on persistence in complex systems. Firstly, the most used definitions of persistence in short-term and long-term cases are presented. The most relevant methods to characterize persistence are then discussed in both cases. A complete literature review is also carried out. We also present and discuss some relevant results on persistence, and give empirical evidence of performance in different detailed case studies, for both short-term and long-term persistence. A perspective on the future of persistence concludes the work.This research has been partially supported by the project PID2020-115454GB-C21 of the Spanish Ministry of Science and Innovation (MICINN). This research has also been partially supported by Comunidad de Madrid, PROMINT-CM project (grant ref: P2018/EMT-4366). J. Del Ser would like to thank the Basque Government for its funding support through the EMAITEK and ELKARTEK programs (3KIA project, KK-2020/00049), as well as the consolidated research group MATHMODE (ref. T1294-19). GCV work is supported by the European Research Council (ERC) under the ERC-CoG-2014 SEDAL Consolidator grant (grant agreement 647423)

    Sustained high serum caspase-3 concentrations and mortality in septic patients

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    Caspase-3 is the main executor of the apoptotic process. Higher serum caspase-3 concentrations in non-survivor compared to survivor septic patients have been found. The objectives of this work (with the increase of sample size to 308 patients, and the determination of serum caspase-3 concentrations also on days 4 and 8 of diagnosis of severe sepsis) were to know whether an association between serum caspase-3 concentrationss during the first week, degree of apoptosis, sepsis severity, and sepsis mortality exists. We collected serum samples of 308 patients with severe sepsis from eight intensive care units on days 1, 4 and 8 to measure concentrations of caspase-3 and caspase-cleaved cytokeratin (CCCK)-18 (to assess degree of apoptosis). End point was 30-day mortality. We found higher serum concentrations of caspase-3 and CCCK-18 in non-survivors compared to survivors on days 1 (p < 0.001), 4 (p < 0.001), and 8 (p < 0.001). We found an association between serum caspase-3 concentrations on days 1, 4 and 8 of severe sepsis diagnosis and serum CCCK-18 concentrations (p < 0.001), SOFA (p < 0.001), serum acid lactic concentrations (p < 0.001), and 30-day sepsis mortality (p < 0.001). The new findings of this work were that an association between serum caspase-3 concentrations during the first week, apoptosis degree, sepsis severity, and sepsis mortality exists

    SPOT and GPRS drifting buoys for HF Radar calibration

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    9th International Workshop on Marine Technology (MARTECH), virtual, 16-18 June 2021Traditional drifting buoys have been designed to measure the surface currents at a nominal depth of 15m with drogues of 6m height. Herein, in order to assess the performance of HF Radars two designs of Lagrangian drifting buoys have been developed and targeted to provide the vertically averaged velocity of the currents in the frst 2 and 0.5 meters of the water column. These are the layer heights of the HF Radars of RAIA observatory. The buoys were made with standard materials and of-the-shelf electronics, to keep costs as low as possibleN

    Efficacy and safety of preoperative preparation with Lugol''s iodine solution in euthyroid patients with Graves’ disease (LIGRADIS Trial): Study protocol for a multicenter randomized trial

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    Background: Currently, both the American Thyroid Association and the European Thyroid Association recommend preoperative preparation with Lugol''s Solution (LS) for patients undergoing thyroidectomy for Graves’ Disease (GD), but their recommendations are based on low-quality evidence. The LIGRADIS trial aims to provide evidence either to support or refute the systematic use of LS in euthyroid patients undergoing thyroidectomy for GD. Methods: A multicenter randomized controlled trial will be performed. Patients =18 years of age, diagnosed with GD, treated with antithyroid drugs, euthyroid and proposed for total thyroidectomy will be eligible for inclusion. Exclusion criteria will be prior thyroid or parathyroid surgery, hyperparathyroidism that requires associated parathyroidectomy, thyroid cancer that requires adding a lymph node dissection, iodine allergy, consumption of lithium or amiodarone, medically unfit patients (ASA-IV), breastfeeding women, preoperative vocal cord palsy and planned endoscopic, video-assisted or remote access surgery. Between January 2020 and January 2022, 270 patients will be randomized for either receiving or not preoperative preparation with LS. Researchers will be blinded to treatment assignment. The primary outcome will be the rate of postoperative complications: hypoparathyroidism, recurrent laryngeal nerve injury, hematoma, surgical site infection or death. Secondary outcomes will be intraoperative events (Thyroidectomy Difficulty Scale score, blood loss, recurrent laryngeal nerve neuromonitoring signal loss), operative time, postoperative length of stay, hospital readmissions, permanent complications and adverse events associated to LS. Conclusions: There is no conclusive evidence supporting the benefits of preoperative treatment with LS in this setting. This trial aims to provide new insights into future Clinical Practice Guidelines recommendations. Trial registration: ClinicalTrials.gov identifier: NCT03980132. © 202

    Challenges in the synthesis of corannulene-based non-planar nanographenes on Au(111) surfaces

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    The on-surface synthesis of non-planar nanographenes is a challenging task. Herein, with the aid of bond-resolving scanning tunneling microscopy (BRSTM) and density functional theory (DFT) calculations, we present a systematic study aiming at the fabrication of corannulene-based nanographenes via intramolecular cyclodehydrogenation on a Au(111) surface. The formation of non-planar targeted products is confirmed to be energetically unfavorable compared to the formation of planar/quasi-planar undesired competing monomer products. In addition, the activation of intermolecular coupling further inhibits the formation of the final targeted product. Although it was not possible to access the corannulene moiety by means of on-surface synthesis, partial cyclodehydrogenation of the molecular precursors was demonstrated.This work was financially supported by the Spanish Agencia Estatal de Investigacion (PID2019-107338RB-C62, PID2019-107338RB-C63, PID2019-110037GB-I00 and MAT2016-78293-C6; AEI/FEDER, UE), the Basque Government (IT-1255-19), the European Union’s Horizon 2020 Program (Grant No. 863098), the Xunta de Galicia (Centro singular de investigacion de Galicia accreditation 2019–2022, ED431G 2019/03), the European Union (European Regional Development Fund-ERDF), and European Union’s Horizon 2020 Research and Innovation Programme under the project MEMO (Grant No. 766864).Peer reviewe

    Low-cost inorganic cation exchange membrane for electrodialysis: optimum processing temperature for the cation exchanger

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    The optimum temperature for fixing zirconium phosphate, obtained by precipitation, on a low-cost ceramic support was determined in order to obtain an inorganic cation exchange membrane for electrodialysis. Zirconium phosphate ion exchange capacity maximised between 450 and 550°C, thus it was considered the optimum processing temperature. The origin of this maximum was investigated by means of X-ray diffraction and termogravimetry and evolved gas analysis. Zirconium phosphate formation by precipitation in the porous network of the support was verified by scanning electron microscopy and energy dispersive X-ray analysis and mercury intrusion porosimetry. The membrane obtained after thermal treatment at 450°C displayed selectivity to the cations present in the spent rinse water of the chromium plating process. This property allows the recovery of chromium by removing the cations through the cation exchange ceramic membrane.The authors wish to express their gratitude to the Spanish Ministry of Science and Innovation for the support given to the research study (National Basic Research Programme, Ref. CTQ2008-06750-C02-02), as well as for the FPU student grant awarded to one of the authors (Ref.: AP2009-4409).Mestre, S.; Sales, S.; Palacios, M.; Lorente, M.; Mallol, G.; Pérez-Herranz, V. (2013). Low-cost inorganic cation exchange membrane for electrodialysis: optimum processing temperature for the cation exchanger. Desalination and Water Treatment. 51(16-18):3317-3324. https://doi.org/10.1080/19443994.2012.749177S331733245116-18Strathmann, H. (2010). Electromembrane Processes: Basic Aspects and Applications. Comprehensive Membrane Science and Engineering, 391-429. doi:10.1016/b978-0-08-093250-7.00048-7Drioli, E., & Fontananova, E. (s. f.). Integrated Membrane Processes. Membrane Operations, 265-283. doi:10.1002/9783527626779.ch12Strathmann, H. (s. f.). Fundamentals in Electromembrane Separation Processes. Membrane Operations, 83-119. doi:10.1002/9783527626779.ch5Alberti, G., Casciola, M., Costantino, U., & Levi, G. (1978). Inorganic ion exchange membranes consisting of microcrystals of zirconium phosphate supported by Kynar®. Journal of Membrane Science, 3(2), 179-190. doi:10.1016/s0376-7388(00)83021-5Semiat, R., & Hasson, D. (s. f.). Seawater and Brackish-Water Desalination with Membrane Operations. Membrane Operations, 221-243. doi:10.1002/9783527626779.ch10Bregman, J. ., & Braman, R. . (1965). Inorganic ion exchange membranes. Journal of Colloid Science, 20(9), 913-922. doi:10.1016/0095-8522(65)90064-4Bishop, H. K., Bittles, J. A., & Guter, G. A. (1969). Investigation of inorganic ion exchange membranes for electrodialysis. Desalination, 6(3), 369-380. doi:10.1016/s0011-9164(00)80226-xRajan, K. S., Boies, D. B., Casolo, A. J., & Bregman, J. . (1966). Inorganic ion-exchange membranes and their application to electrodialysis. Desalination, 1(3), 231-246. doi:10.1016/s0011-9164(00)80255-6INAMUDDIN, KHAN, S., SIDDIQUI, W., & KHAN, A. (2007). Synthesis, characterization and ion-exchange properties of a new and novel ‘organic–inorganic’ hybrid cation-exchanger: Nylon-6,6, Zr(IV) phosphate. Talanta, 71(2), 841-847. doi:10.1016/j.talanta.2006.05.042HELEN, M., VISWANATHAN, B., & MURTHY, S. (2007). Synthesis and characterization of composite membranes based on α-zirconium phosphate and silicotungstic acid. Journal of Membrane Science, 292(1-2), 98-105. doi:10.1016/j.memsci.2007.01.018Yu.S. Dzyaz’ko, V.N. Belyakov, N.V. Stefanyak, S.L. Vasilyuk, Anion-exchange properties of composite ceramic membranes containing hydrated zirconium dioxide, Russ. J. Appl. Chem. 79 (2006) 769–773.Linkov, V. ., & Belyakov, V. . (2001). Novel ceramic membranes for electrodialysis. Separation and Purification Technology, 25(1-3), 57-63. doi:10.1016/s1383-5866(01)00090-9Linkov, V. M., Dzyaz’ko, Y. S., Belyakov, V. N., & Atamanyuk, V. Y. (2007). Inorganic composite membranes for electrodialytic desaltination. Russian Journal of Applied Chemistry, 80(4), 576-581. doi:10.1134/s1070427207040118El-Sourougy, M. R., Zaki, E. E., & Aly, H. F. (1997). Transport characteristics of ceramic supported zirconium phosphate membrane. Journal of Membrane Science, 126(1), 107-113. doi:10.1016/s0376-7388(96)00273-6Sánchez, E., Mestre, S., Pérez-Herranz, V., & García-Gabaldón, M. (2005). Síntesis de membranas cerámicas para la regeneración de baños de cromado agotados. Boletín de la Sociedad Española de Cerámica y Vidrio, 44(6), 409-414. doi:10.3989/cyv.2005.v44.i6.340Sánchez, E., Mestre, S., Pérez-Herranz, V., Reyes, H., & Añó, E. (2006). Membrane electrochemical reactor for continuous regeneration of spent chromium plating baths. Desalination, 200(1-3), 668-670. doi:10.1016/j.desal.2006.03.475Alberti, G., Casciola, M., Costantino, U., & Vivani, R. (1996). Layered and pillared metal(IV) phosphates and phosphonates. Advanced Materials, 8(4), 291-303. doi:10.1002/adma.19960080405Alberti, G., & Torracca, E. (1968). Crystalline insoluble salts of polybasic metals - II. Synthesis of crystalline zirconium or titanium phosphate by direct precipitation. Journal of Inorganic and Nuclear Chemistry, 30(1), 317-318. doi:10.1016/0022-1902(68)80096-xTrobajo, C., Khainakov, S. A., Espina, A., & García, J. R. (2000). On the Synthesis of α-Zirconium Phosphate. Chemistry of Materials, 12(6), 1787-1790. doi:10.1021/cm0010093Alberti, G. (1978). Syntheses, crystalline structure, and ion-exchange properties of insoluble acid salts of tetravalent metals and their salt forms. Accounts of Chemical Research, 11(4), 163-170. doi:10.1021/ar50124a007Rajeh, A. O., & szirtes, L. (1995). Investigations of crystalline structure of gamma-zirconium phosphate. Journal of Radioanalytical and Nuclear Chemistry Articles, 196(2), 319-322. doi:10.1007/bf02038050Krogh Andersen, A. M., Norby, P., Hanson, J. C., & Vogt, T. (1998). Preparation and Characterization of a New 3-Dimensional Zirconium Hydrogen Phosphate, τ-Zr(HPO4)2. Determination of the Complete Crystal Structure Combining Synchrotron X-ray Single-Crystal Diffraction and Neutron Powder Diffraction. Inorganic Chemistry, 37(5), 876-881. doi:10.1021/ic971060hFeng, Y., He, W., Zhang, X., Jia, X., & Zhao, H. (2007). The preparation of nanoparticle zirconium phosphate. Materials Letters, 61(14-15), 3258-3261. doi:10.1016/j.matlet.2006.11.132Clearfield, A. (2000). INORGANIC ION EXCHANGERS, PAST, PRESENT, AND FUTURE. Solvent Extraction and Ion Exchange, 18(4), 655-678. doi:10.1080/07366290008934702Szirtes, L., Shakshooki, S. K., Szeleczky, A. M., & Rajeh, A. O. (1998). Thermoanalyncal Investigation of Some Layered Zirconium Salts and Their Various Derivatives I. Journal of Thermal Analysis and Calorimetry, 51(2), 503-515. doi:10.1007/bf03340188Al-Othman, A., Tremblay, A. Y., Pell, W., Letaief, S., Burchell, T. J., Peppley, B. A., & Ternan, M. (2010). Zirconium phosphate as the proton conducting material in direct hydrocarbon polymer electrolyte membrane fuel cells operating above the boiling point of water. Journal of Power Sources, 195(9), 2520-2525. doi:10.1016/j.jpowsour.2009.11.052Thakkar, R., Patel, H., & Chudasama, U. (2007). A comparative study of proton transport properties of zirconium phosphate and its metal exchanged phases. Bulletin of Materials Science, 30(3), 205-209. doi:10.1007/s12034-007-0036-3Jiang, P., Pan, B., Pan, B., Zhang, W., & Zhang, Q. (2008). A comparative study on lead sorption by amorphous and crystalline zirconium phosphates. 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    Effectiveness and Safety of the Sequential Use of a Second and Third Anti-TNF Agent in Patients with Inflammatory Bowel Disease: Results from the Eneida Registry

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    Background: The effectiveness of the switch to another anti-tumor necrosis factor (anti-TNF) agent is not known. The aim of this study was to analyze the effectiveness and safety of treatment with a second and third anti-TNF drug after intolerance to or failure of a previous anti-TNF agent in inflammatory bowel disease (IBD) patients. Methods: We included patients diagnosed with IBD from the ENEIDA registry who received another anti-TNF after intolerance to or failure of a prior anti-TNF agent. Results: A total of 1122 patients were included. In the short term, remission was achieved in 55% of the patients with the second anti-TNF. The incidence of loss of response was 19% per patient-year with the second anti-TNF. Combination therapy (hazard ratio [HR], 2.4; 95% confidence interval [CI], 1.8-3; P < 0.0001) and ulcerative colitis vs Crohn''s disease (HR, 1.6; 95% CI, 1.1-2.1; P = 0.005) were associated with a higher probability of loss of response. Fifteen percent of the patients had adverse events, and 10% had to discontinue the second anti-TNF. Of the 71 patients who received a third anti-TNF, 55% achieved remission. The incidence of loss of response was 22% per patient-year with a third anti-TNF. Adverse events occurred in 7 patients (11%), but only 1 stopped the drug. Conclusions: Approximately half of the patients who received a second anti-TNF achieved remission; nevertheless, a significant proportion of them subsequently lost response. Combination therapy and type of IBD were associated with loss of response. Remission was achieved in almost 50% of patients who received a third anti-TNF; nevertheless, a significant proportion of them subsequently lost response

    Castration-Resistant Prostate Cancer Tissue Acquisition From Bone Metastases for Molecular Analyses.

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    Background The urgent need for castration-resistant prostate cancer molecular characterization to guide treatment has been constrained by the disease's predilection to metastasize primarily to bone. We hypothesized that the use of clinical and imaging criteria could maximize tissue acquisition from bone marrow biopsies (BMBs). We aimed to develop a score for the selection of patients undergoing BMB.Materials and methods A total of 115 BMBs were performed in 101 patients: 57 were included in a derivation set and 58 were used as the validation set. The clinical and laboratory data and prebiopsy computed tomography parameters (Hounsfield units [HUs]) were determined. A score for the prediction of biopsy positivity was developed from logistic regression analysis of the derivation set and tested in the validation set.Results Of the 115 biopsy specimens, 75 (62.5%) were positive; 35 (61.4%) in the test set and 40 (69%) in the validation set. On univariable analysis, hemoglobin (P = .019), lactate dehydrogenase (P = .003), prostate-specific antigen (P = .005), and mean HUs (P = .004) were selected. A score based on the LDH level (≥ 225 IU/L) and mean HUs (≥ 125) was developed in multivariate analysis and was associated with BMB positivity in the validation set (odds ratio, 5.1; 95% confidence interval, 1.9%-13.4%; P = .001). The area under the curve of the score was 0.79 in the test set and 0.77 in the validation set.Conclusion BMB of the iliac crest is a feasible technique for obtaining tumor tissue for genomic analysis in patients with castration-resistant prostate cancer metastatic to the bone. A signature based on the mean HUs and LDH level can predict a positive yield with acceptable internal validity. Prospective studies of independent cohorts are needed to establish the external validity of the score

    Circulating tumor cells criteria (CyCAR) versus standard RECIST criteria for treatment response assessment in metastatic colorectal cancer patients

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    The use of circulating tumor cells (CTCs) as indicators of treatment response in metastatic colorectal cancer (mCRC) needs to be clarified. The objective of this study is to compare the Response Evaluation Criteria in Solid Tumors (RECIST) with the Cytologic Criteria Assessing Response (CyCAR), based on the presence and phenotypic characterization of CTCs, as indicators of FOLFOX–bevacizumab treatment response. We observed a decrease of CTCs (42.8 vs. 18.2%) and VEGFR positivity (69.7% vs. 41.7%) after treatment. According to RECIST, 6.45% of the patients did not show any clinical benefit, whereas 93.55% patients showed a favorable response at 12 weeks. According to CyCAR, 29% had a non-favorable response and 71% patients did not. No significant differences were found between the response assessment by RECIST and CyCAR at 12 or 24 weeks. However, in the multivariate analysis, RECIST at 12 weeks and CyCAR at 24 weeks were independent prognostic factors for OS (HR: 0.1, 95% CI 0.02–0.58 and HR: 0.35, 95% CI 0.12–0.99 respectively). CyCAR results were comparable to RECIST in evaluating the response in mCRC and can be used as an alternative when the limitation of RECIST requires additional response analysis techniques.This work was supported by Roche Spain and a Ph.D. grant from the University of Granada
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