319 research outputs found

    A Fused Donor−Acceptor System Based on an Extended Tetrathiafulvalene and a Ruthenium Complex of Dipyridoquinoxaline

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    An application of the Horner−Wadsworth−Emmons reaction carried out on a ruthenium compound as the electrophilic precursor is described for the synthesis of fused donor−acceptor system 1 based on an extended tetrathiafulvalene and a ruthenium complex of dipyridoquinoxaline units

    Dual Signaling System with an Extended-Tetrathiafulvalene–Phenanthroline Dyad Acting as an Electrooptical Cation Chemosensor

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    A tetrathiafulvalene donor has been annulated to 2,3-di(1H-2-pyrrolyl)quinoxaline affording a new chemosensor 1, which shows a unique optical selectivity and reactivity for the fluoride ion over other anions in CH2Cl2 leading to a colorimetric response. Electrochemical polymerization of 1 occurred in the presence of fluoride

    Estimating the return on investment of selected infection prevention and control interventions in healthcare settings for preparing against novel respiratory viruses: modelling the experience from SARS-CoV-2 among health workers.

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    Insufficient infection prevention and control (IPC) practices in healthcare settings increase the SARS-CoV-2 infection risk among health workers. This study aimed to examine the level of preparedness for future outbreaks. We modelled the experience from the COVID-19 pandemic and assessed the return on investment on a global scale of three IPC interventions to prevent SARS-CoV-2 infections among health workers: enhancing hand hygiene; increasing access to personal protective equipment (PPE); and combining PPE, with a scale-up of IPC training and education (PPE+). Our analysis covered seven geographic regions, representing a combination of World Health Organization (WHO) regions and the Organisation for Economic Co-operation and Development (OECD) countries. Across all regions, we focused on the first 180 days of the pandemic in 2020 between January 1st and June 30th. We used an extended version of a susceptible-infectious-recovered compartmental model to measure the level of IPC preparedness. Data were sourced from the WHO COVID-19 Detailed Surveillance Database. In all regions, the PPE + intervention would have averted the highest number of new SARS-CoV-2 infections compared to the other two interventions, ranging from 6562 (95% CI 4873-8779) to 38,170 (95% CI 33,853-41,901) new infections per 100,000 health workers in OECD countries and in the South-East Asia region, respectively. Countries in the South-East Asia region and non-OECD countries in the Western Pacific region were poised to achieve the highest level of savings by scaling up the PPE + intervention. Our results not only support efforts to make an economic case for continuing investments in IPC interventions to halt the COVID-19 pandemic and protect health workers, but could also contribute to efforts to improve preparedness for future outbreaks. This work was funded by WHO, with support by the German Federal Ministry of Health for the WHOResearch and Development Blueprint for COVID-19

    Combined paclitaxel and gemcitabine as first-line treatment in metastatic non-small cell lung cancer: a multicentre phase II study

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    The efficacy and toxicity of combined paclitaxel and gemcitabine was evaluated in 54 chemotherapy-naive patients with metastatic non-small cell lung cancer (NSCLC). Gemcitabine i.v. 1000 mg/m2was administered on days 1 and 8 and paclitaxel 200 mg/m2as a continuous 3-hour infusion on day 1. Treatment was repeated every 21 days. Patients had a median age of 53 years. ECOG performance status was 0 or 1 in 48 patients. 41 patients (75.9%) had initial stage IV disease; histology was mainly adenocarcinoma (46.3%). 2 patients (4.3%) achieved a complete response and 15 (31.9%) achieved a partial response giving an overall response rate of 36.2% (95% CI: 22.4–49.9%); 19 patients (40.4%) had stable disease and 10 (21.3%) had progressive disease. The median survival time was 51 weeks (95% CI: 46.5–59.3), with a 1-year survival probability of 0.48 (95% CI: 0.34–0.63). Grade 3/4 neutropenia and febrile neutropenia occurred in 15.2% and 2.2% of courses, respectively. Grade 3/4 thrombocytopenia was rare (1.8% of courses). Peripheral neurotoxicity developed in 25 patients (47.2%), mostly grade 1/2. Arthalgia/myalgia was observed in 30 patients (56.6%), generally grade 1 or 2. Grade 3 abnormal levels of serum glutamate pyruvate transaminase (SGPT) and serum glutamate oxaloacetate transaminase (SGOT) occurred in 5 patients (9.4%) and 1 patient (1.9%), respectively. Combined paclitaxel and gemcitabine is an active and well-tolerated regimen for the treatment of advanced NSCLC, and warrants further investigation in comparative, randomized trials. © 2001 Cancer Research Campaign http://www.bjcancer.co

    Taylor-like vortices in the shear-banding flow of giant micelles

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    Using flow visualizations in Couette geometry, we demonstrate the existence of Taylor-like vortices in the shear-banding flow of a giant micelles system. We show that vortices stacked along the vorticity direction develop concomitantly with interfacial undulations. These cellular structures are mainly localized in the induced band and their dynamics is fully correlated with that of the interface. As the control parameter increases, we observe a transition from a steady vortex flow to a state where pairs of vortices are continuously created and destroyed. Normal stress effects are discussed as potential mechanisms driving the three-dimensional flow.Comment: 5 pages, 4 figure

    A learning health systems approach to integrating electronic patient-reported outcomes across the health care organization

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    Introduction: Foundational to a learning health system (LHS) is the presence of a data infrastructure that can support continuous learning and improve patient outcomes. To advance their capacity to drive patient-centered care, health systems are increasingly looking to expand the electronic capture of patient data, such as electronic patient-reported outcome (ePRO) measures. Yet ePROs bring unique considerations around workflow, measurement, and technology that health systems may not be poised to navigate. We report on our effort to develop generalizable learnings that can support the integration of ePROs into clinical practice within an LHS framework. Methods: Guided by action research methodology, we engaged in iterative cycles of planning, acting, observing, and reflecting around ePRO use with two primary goals: (1) mobilize an ePRO community of practice to facilitate knowledge sharing, and (2) establish guidelines for ePRO use in the context of LHS practice. Multiple, emergent data collection activities generated generalizable guidelines that document the tangible best practices for ePRO use in clinical care. We organized guidelines around thematic areas that reflect LHS structures and stakeholders. Results: Three core thematic areas (and 24 guidelines) emerged. The theme of governance reflects the importance of leadership, knowledge management, and facilitating organizational learning around best practice models for ePRO use. The theme of integration considers the intersection of workflow, technology, and human factors for ePROs across areas of care delivery. Lastly, the theme of reporting reflects critical considerations for curating data and information, designing system functions and interactions, and presentation of ePRO data to support the translation of knowledge to action. Conclusions: The guidelines produced from this work highlight the complex, multidisciplinary nature of implementing change within LHS contexts, and the value of action research approaches to enable rapid, iterative learning that leverages the knowledge and experience of communities of practice

    Shear-banding in a lyotropic lamellar phase, Part 1: Time-averaged velocity profiles

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    Using velocity profile measurements based on dynamic light scattering and coupled to structural and rheological measurements in a Couette cell, we present evidences for a shear-banding scenario in the shear flow of the onion texture of a lyotropic lamellar phase. Time-averaged measurements clearly show the presence of structural shear-banding in the vicinity of a shear-induced transition, associated to the nucleation and growth of a highly sheared band in the flow. Our experiments also reveal the presence of slip at the walls of the Couette cell. Using a simple mechanical approach, we demonstrate that our data confirms the classical assumption of the shear-banding picture, in which the interface between bands lies at a given stress σ\sigma^\star. We also outline the presence of large temporal fluctuations of the flow field, which are the subject of the second part of this paper [Salmon {\it et al.}, submitted to Phys. Rev. E]

    Spatially resolved quantitative rheo-optics of complex fluids in a microfluidic device

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    In this study, we use microparticle image velocimetry (μ-PIV) and adapt a commercial birefringence microscopy system for making full-field, quantitative measurements of flow-induced birefringence (FIB) for the purpose of microfluidic, optical rheometry of two wormlike micellar solutions. In combination with conventional rheometric techniques, we use our microfluidic rheometer to study the properties of a shear-banding solution of cetylpyridinium chloride (CPyCl) with sodium salicylate (NaSal) and a nominally shear-thinning system of cetyltrimethylammonium bromide (CTAB) with NaSal across many orders of magnitude of deformation rates (10-2 ≤ math ≤ 104s-1). We use μ-PIV to quantify the local kinematics and use the birefringence microscopy system in order to obtain high-resolution measurements of the changes in molecular orientation in the wormlike fluids under strong deformations in a microchannel. The FIB measurements reveal that the CPyCl system exhibits regions of localized, high optical anisotropy indicative of shear bands near the channel walls, whereas the birefringence in the shear-thinning CTAB system varies more smoothly across the width of the channel as the volumetric flow rate is increased. We compare the experimental results to the predictions of a simple constitutive model, and we document the breakdown in the stress-optical rule as the characteristic rate of deformation is increased.National Science Foundation (U.S.) (Graduate Research Fellowship

    The effects of user characteristics on query performance in the presence of information request ambiguity

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    This paper investigates the effects of personality characteristics on individuals' abilities to compose queries from information requests containing various types of ambiguity. In particular, this research examines the effects of user personality characteristics on query performance in the presence of information requests that contained no extraneous, syntactic, or both extraneous and syntactic ambiguities. The results indicate that personality characteristics significantly affect users' abilities to compose accurate queries. Neuroticism, agreeableness, openness to experience, and conscientiousness significantly affected the number of errors made in the query formulations. Conscientiousness affected the length of time taken to compose the queries and neuroticism affected the confidence users had in the accuracy of their queries. Although several personality dimensions affected query performance, no significant interactions between personality dimensions and ambiguity were detected. Furthermore, both query complexity and information request ambiguity exhibited greater impacts on query performance than personality characteristics. Hence, organizations should attempt to train users to deal with query complexity and information request ambiguity before modifying their training programs for personality characteristics

    The synthesis of the rhamnogalacturonan II component 3-deoxy-D-manno-2-octulosonic acid (Kdo) is required for pollen tube growth and elongation

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    Despite a very complex structure, the sugar composition of the rhamnogalacturonan II (RG-II) pectic fraction is extremely conserved. Among its constituting monosaccharides is the seldom-observed eight-carbon sugar 3-deoxy-D-manno-octulosonic acid (Kdo), whose phosphorylated precursor is synthesized by Kdo-8-P synthase. As an attempt to alter specifically the RG-II structure in its sugar composition and assess the consequences on the function of RG-II in cell wall and its relationship with growth, Arabidopsis null mutants were sought in the genes encoding Kdo-8-P synthase. Here, the isolation and characterization of one null mutant for the isoform 1 (AtkdsA1-S) and two distinct null mutants for the isoform 2 of Arabidopsis Kdo-8-P synthase (AtkdsA2-V and AtkdsA2-S) are described. Evidence is provided that AtkdsA2 gene expression is preferentially associated with plantlet organs displaying a meristematic activity, and that it accounts for 75% of the mRNAs to be translated into Kdo-8-P synthase. Furthermore, this predominant expression of AtKDSA2 over AtKDSA1 was confirmed by quantification of the cytosolic Kdo content in the mutants, in a variety of ecotypes. The inability to identify a double knockout mutant originated from pollen abortions, due to the inability of haploid pollen of the AtkdsA1- AtkdsA2- genotype to form an elongated pollen tube properly and perform fertilization
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