365 research outputs found

    Parallelisation Technique for Serial 3D Seismic Codes: SMS Approach

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    We investigate a fast and easy way to parallelise seismological serial codes mainly oriented for simulating the seismic wave propagation through anelastic dissipative media. Having an efficient modelling tool is important in both assessing strong ground motion and mitigation of seismic hazard when the site effects are considered, and in crustal propagation when the crustal geological structures are of interest. Our chosen case study is repre- sentative of a set of such seismological 3D problems. The Scalable Modelling System (SMS) tool for paralleliza- tion is considered. The IBM SP5 native compiler has been used. Results such as Speed-Up and Efficiency are shown and discussed. SMS can run both in shared and distributed memory environments. The greater advantages of using SMS in such environments become apparent with the utilisation of a higher number of multiprocessor machines arranged in a cluster. We also demonstrate how successful porting from serial to parallel codes is re- alised by way of minimal instructions (6% of the serial original code only) provided that an ad hoc profiling analysis of the serial code is first performed

    Propene Polymerization Promoted by C2-Symmetric Metallocene Catalysts: From Atactic to Isotactic Polypropene in Consequence of an Isotope Effect

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    We studied the polymerization of propene-2-d promoted by the prototypical isotactic-specific catalyst system rac-ethylenebis(4,5,6,7-tetrahydro-1-indenyl)ZrCl2/MAO. In this communication, we report the results of our investigation, documenting a large isotope effect on the balance between polyinsertion and epimerization and, therefore, on the stereospecificity. The mechanistic implications of such results are also discusse

    A thermophysical study of the melting process in alkyl chain metal n-alkanoates: The thallium (I) series

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    The peculiar thermal behavior of the thallium(I) n-alkanoates series (consisting in several transitions between polymorphic and mesomorphic phases) in comparison with other metallic n-alkanoates series is stated. The allowance of highly accurate adiabatic heat capacity data permits a study of the CH2CH2 contributions to the lattice heat capacity curve at low temperature. Moreover, in this series an anomalous gradual enhancement of the lattice heat capacity has been interpreted from vibrational spectroscopy results as a noncooperative effect due to the internal hindered rotation of the alkyl chain (formation of gauche defects, even in the solid state). The thermodynamics of the “stepwise melting process” from the totally ordered solid at low temperature to the isotropic liquid is based on a revised lattice heat-capacity curve. This was used to evaluate the energy and entropy not only of the clear first order transitions present in the series but also of the described noncooperative effect. The CH2CH2 enthalpy and entropy contribution for this series is estimated and a comparison with the published values for other series is carried out. Moreover, the texture of the mesophases is revealed by polarized light microscopy. © 1999 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69602/2/JCPSA6-111-8-3590-1.pd

    Negative hyperselection of patients with RAS and BRAF wild-type metastatic colorectal cancer who received panitumumab-based maintenance therapy

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    PURPOSE We assessed the prognostic/predictive role of primary tumor sidedness and uncommon alterations of anti\u2013epidermal growth factor receptor (EGFR) primary resistance (primary resistance in RAS and BRAF wild-type metastatic colorectal cancer patients treated with anti-EGFR monoclonal antibodies [PRESSING] panel) in patients with RAS/BRAF wild-type (wt) metastatic colorectal cancer (mCRC) who were randomly assigned to panitumumab plus fluorouracil, leucovorin, and oxaliplatin (FOLFOX-4) induction followed by maintenance with panitumumab with or without fluorouracil (FU) plus leucovorin (LV); Valentino trial (ClinicalTrials.gov identifier: NCT02476045). PATIENTS AND METHODS This prespecified retrospective analysis included 199 evaluable patients with RAS/ BRAF wt. The PRESSING panel included the following: immunohistochemistry (IHC) and in situ hybridization for HER2/MET amplification, IHC with or without RNA sequencing for ALK/ROS1/NTRKs/RET fusions, next-generation sequencing for HER2/PIK3CAex.20/PTEN/AKT1 and RAS mutations with low mutant allele fraction, and multiplex polymerase chain reaction for microsatellite instability. PRESSING status (any positive biomarker v all negative) and sidedness were correlated with overall response rate (ORR), progression-free survival (PFS), and overall survival (OS) in the study population and by treatment arm. RESULTS Overall, left- and right-sided tumors were 85.4% and 14.6%, respectively, and PRESSING-negative and -positive tumors were 75.4% and 24.6%, respectively. At a median follow-up of 26 months, inferior outcomes were consistently observed in right- versus left-sided tumors for ORR (55.2% v 74.1%; P = .037), PFS (8.4 v 11.5 months; P = .026), and OS (2-year rate: 50.2% v 65.1%; P = .062). Similar results were observed in the PRESSING-positive versus PRESSING-negative subgroup for ORR (59.2% v 75.3%; P = .030), PFS (7.7 v 12.1 months; P, .001), and OS (2-year rate: 48.1% v 68.1%; P = .021). The PFS benefit of FU plus LV added to panitumumab maintenance, reported in the study, was independent from sidedness and PRESSING status (interaction for PFS P = .293 and .127, respectively). However, outcomes were extremely poor in patients who received single-agent panitumumab and had right-sided tumors (median PFS, 7.7 months; 2-year OS, 38.5%) or PRESSING-positive tumors (median PFS, 7.4 months; 2-year OS, 47.0%). CONCLUSION The combined assessment of sidedness and molecular alterations of anti-EGFR primary resistance identified a consistent proportion of patients with RAS/BRAF\u2013wt mCRC who had inferior benefit from initial anti-EGFR\u2013based regimens, particularly after maintenance with single-agent anti-EGFRs

    A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

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    Uma revisĂŁo sobre polimerização de olefinas usando catalisadores Ziegler-Natta heterogĂȘneos

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