Analytic continuation by averaging Pad\'e approximants

The ill-posed analytic continuation problem for Green's functions and self-energies is investigated by revisiting the Pad\'{e} approximants technique. We propose to remedy the well-known problems of the Pad\'{e} approximants by performing an average of several continuations, obtained by varying the number of fitted input points and Pad\'{e} coefficients independently. The suggested approach is then applied to several test cases, including Sm and Pr atomic self-energies, the Green's functions of the Hubbard model for a Bethe lattice and of the Haldane model for a nano-ribbon, as well as two special test functions. The sensitivity to numerical noise and the dependence on the precision of the numerical libraries are analysed in detail. The present approach is compared to a number of other techniques, i.e. the non-negative least-square method, the non-negative Tikhonov method and the maximum entropy method, and is shown to perform well for the chosen test cases. This conclusion holds even when the noise on the input data is increased to reach values typical for quantum Monte Carlo simulations. The ability of the algorithm to resolve fine structures is finally illustrated for two relevant test functions.Comment: 10 figure

First international descriptive and interventional survey for cholesterol and non-cholesterol sterol determination by gas- and liquid- chromatography–Urgent need for harmonisation of analytical methods

Serum concentrations of lathosterol, the plant sterols campesterol and sitosterol and the cholesterol metabolite 5α-cholestanol are widely used as surrogate markers of cholesterol synthesis and absorption, respectively. Increasing numbers of laboratories utilize a broad spectrum of well-established and recently developed methods for the determination of cholesterol and non-cholesterol sterols (NCS). In order to evaluate the quality of these measurements and to identify possible sources of analytical errors our group initiated the first international survey for cholesterol and NCS. The cholesterol and NCS survey was structured as a two-part survey which took place in the years 2013 and 2014. The first survey part was designed as descriptive, providing information about the variation of reported results from different laboratories. A set of two lyophilized pooled sera (A and B) was sent to twenty laboratories specialized in chromatographic lipid analysis. The different sterols were quantified either by gas chromatography-flame ionization detection, gas chromatography- or liquid chromatography-mass selective detection. The participants were requested to determine cholesterol and NCS concentrations in the provided samples as part of their normal laboratory routine. The second part was designed as interventional survey. Twenty-two laboratories agreed to participate and received again two different lyophilized pooled sera (C and D). In contrast to the first international survey, each participant received standard stock solutions with defined concentrations of cholesterol and NCS. The participants were requested to use diluted calibration solutions from the provided standard stock solutions for quantification of cholesterol and NCS. In both surveys, each laboratory used its own internal standard (5α-cholestane, epicoprostanol or deuterium labelled sterols). Main outcome of the survey was, that unacceptably high interlaboratory variations for cholesterol and NCS concentrations are reported, even when the individual laboratories used the same calibration material. We discuss different sources of errors and recommend all laboratories analysing cholesterol and NCS to participate in regular quality control programs

ROTEM and vitro reversal of warfarin with APCC

Background: Warfarin-treated patients with a prolonged Prothrombin Time (PT) can have a normal rotational thromboelastometry (ROTEM) clotting time (CT). A previous in vitro study found that activated prothrombin complex concentrates (APCC) could reverse an albumin-induced coagulopathy monitored with ROTEM, but that prothrombin complex concentrates (PCC) could not. The aim of this study was to investigate the ability of ROTEM to monitor the in vitro reversal of warfarin-induced coagulopathy using APCC and to define an APCC dose response.Method: During the routine control of PT in 27 patients treated with warfarin, one extra 4.5 ml test tube of citrated whole blood was retrieved. Two concentrations of tissue factor ROTEM tissue factor (TF) activating reagents were used: a standard ROTEM ExTEM and a diluted 1:19000 concentration. The effects of two separate doses of APCC added in vitro corresponding to in vivo doses of 50 IE or 100 IE/kg were then studied on the ROTEM.Results: The ROTEM EXTEM CT was prolonged beyond the upper normal range of 68 s in patients with PT &gt;3.0, with a correlation coefficient of 0.88 to PT. ROTEM with the ExTEM reagent alongside high and low doses of APCC resulted in a significant shortening of median CT, both compared to baseline (100 s) and after low (65 s) and high doses (57 s). This was most evident in patients with PT &gt;2.0. ROTEM signals of clot propagation to clot formation time (CFT) and α angle had the reverse pattern. There was no effect on maximal clot strength with APCC. With the diluted TF no CT shortening was found with APCC.Conclusion: A clear dose response of APCC added in vitro to correct the effects of warfarin on ROTEM EXTEM CT was verified. ROTEM CT should be tested with non-activated PCC for in vivo reversal of warfarin in patients along with verification of a normalised PT. Further studies are needed to verify if a ROTEM CT in the lower normal range of &lt;57-65 s, as found in our in vitro APCC-spiked warfarin blood, is safe for invasive procedures.</p

Mechanical complications of central venous catheter insertions : A retrospective multicenter study of incidence and risks

BACKGROUND: Incidence and risk factors for complications after insertion of central venous catheters have previously been reported for smaller cohorts. The aim of this observational multicenter study was to study risk factors for mechanical complications in a large, recently collected cohort of patients.METHODS: Records of central venous catheter insertions from 8 hospitals in southern Sweden from 2013 to 2016 were collected from the regional chart system. Data on blood coagulation tests, use of ultrasonography, central venous catheter location, bore size, number of needle passes, arterial puncture, the chronological order of the central venous catheter insertion, and mechanical complications were extracted. Only one insertion/patient was included using worst-case selection criteria. Predefined primary outcome was mechanical complications defined as bleeding, pneumothorax, nerve injury, or malignant arrhythmia. Severe mechanical complications were defined as bleeding requiring intervention or transfusion, pneumothorax, persistent nerve injury, or non-self-limiting arrhythmias.RESULTS: We included 10 949 insertions and identified 118 (1.1%) incidents of mechanical complication, of which 85 (0.8%) were bleedings, 21 (0.2%) were pneumothoraces, 7 (0.06%) were transient nerve injuries, and 5 (0.05%) were self-limiting arrhythmias. Severe mechanical complications occurred in 23 (0.2%) cases.CONCLUSIONS: In this retrospective, multicenter observational study on 10 949 central venous catheter insertions, mechanical complications were rare. Preprocedural coagulopathy, number of needle passes, and arterial puncture were associated with grade 2-4 bleeding. Subclavian vein insertions, arterial puncture, and chronological order of the central venous catheter insertion were associated with pneumothorax

Comparison of two infusion rates of antithrombin concentrate in cardiopulmonary bypass surgery

Background: Antithrombin concentrate (AT) is used to treat heparin resistance (HR) in cardiac surgery. It is usually given slowly due to the fear of anaphylaxis. This may delay cardiac catheterisation and the start of cardiopulmonary bypass (CPB). HR is often defined as the failure to reach or maintain a target activated clotting time (ACT) despite a standard dose of heparin. It is not generally possible to predict which patients will display HR, although there are known risk factors. Routine early administration of AT before heparinisation is probably not cost-effective. Infusing AT relatively quickly after demonstrating HR may be more cost-effective, while not delaying surgery. The aim of this study is to investigate the safety and side effects of a faster infusion of AT. Methods: Forty patients undergoing elective heart surgery were included and randomised to two groups in a double-blind fashion. Each group received 1000 IU of AT intravenously (IV). One group received a slow infusion (100 IU/min) before full-dose heparinisation. The other group received a fast infusion (250 IU/min). Haemodynamic and respiratory data were recorded. Any adverse effects were noted. Thrombin-antithrombin, anti-Xa and antithrombin levels in plasma were measured. Results: No anaphylaxis occurred in either group. No differences were found regarding haemodynamics, respiration or laboratory results. Two patients experienced major haemorrhage and recovered; there were two deaths, thought to be unrelated to the study drugs. Conclusion: AT can be infused at a rate of 250 IU/min. This is faster than the current recommendation of 100 IU/min. This rate of infusion allows restricting AT infusion to those patients who display HR, without delaying surgery. Optimal anticoagulant therapy for CPB probably includes point-of-care measurement of ACT and plasma AT and small, but rapid, infusions of AT in heparin-resistant patients

Retrospective analysis of coagulation parameters at epidural anaesthesia catheter withdrawal after esophageal resection

The gCube System - gCube Switch Button Widget -------------------------------------------------- gCube Switch Button Widget is a GWT Widget that can be used as a Checbox with a iOS sliding effect. This software is part of the gCube Framework (https://www.gcube-system.org/): an open-source software toolkit used for building and operating Hybrid Data Infrastructures enabling the dynamic deployment of Virtual Research Environments by favouring the realisation of reuse oriented policies. The projects leading to this software have received funding from a series of European Union programmes including: * the Sixth Framework Programme for Research and Technological Development - DILIGENT (grant no. 004260); * the Seventh Framework Programme for research, technological development and demonstration - D4Science (grant no. 212488), D4Science-II (grant no. 239019),ENVRI (grant no. 283465), EUBrazilOpenBio (grant no. 288754), iMarine (grant no. 283644); * the H2020 research and innovation programme - BlueBRIDGE (grant no. 675680), EGIEngage (grant no. 654142), ENVRIplus (grant no. 654182), Parthenos (grant no. 654119), SoBigData (grant no. 654024); Version -------------------------------------------------- 1.0.0-4.6.0-125951 (2017-07-31) Please see the file named "changelog.xml" in this directory for the release notes. Authors -------------------------------------------------- * Massimiliano Assante ([email protected]), Istituto di Scienza e Tecnologie dell'Informazione "A. Faedo" - CNR, Pisa (Italy). Maintainers ----------- * Massimiliano Assante ([email protected]), Istituto di Scienza e Tecnologie dell'Informazione "A. Faedo" - CNR, Pisa (Italy). Download information -------------------------------------------------- Source code is available from SVN: http://svn.research-infrastructures.eu/public/d4science/gcube/trunk/portlets/widgets/switch-button-widget Binaries can be downloaded from the gCube website: https://www.gcube-system.org/ Installation -------------------------------------------------- Installation documentation is available on-line in the gCube Wiki: https://wiki.gcube-system.org/gcube/index.php Documentation -------------------------------------------------- Documentation is available on-line in the gCube Wiki: https://wiki.gcube-system.org/gcube/index.php Support -------------------------------------------------- Bugs and support requests can be reported in the gCube issue tracking tool: https://support.d4science.org/projects/gcube/ Licensing -------------------------------------------------- This software is licensed under the terms you may find in the file named "LICENSE" in this directory