On-line solid phase extraction of bismuth by FI-HG-AAS using l-proline immobilised on carbon nanotubes combined with factorial design

This study explores further the analytical capabilities of functionalised multiwalled carbon nanotubes with l-proline (pro-MWCNTs) for the reliable preconcentration and determination of Bi(III) in waters using an on-line flow injection hydride generation atomic absorption spectrometry (FI-HG-AAS) system. To avoid carbon nanoparticles aggregation, the preconcentration was carried out on a microcolumn filled with functionalised pro-MWCNTs and a low molecular weight polyethylene. The optimisation was performed by employing a full factorial design. The factors related to the optimisation process were the concentration of eluent and pH of the sample. The best performance was achieved packing the substrate in a microcolumn of 2.3mm (i.d)×25mm (pro-MWCNTs net length: 10mm), the pH was 7.0 and the concentration of the eluent (HCl) was 10% (v/v). Under optimal conditions, the adsorption capacity of the substrate was found to be 0.1mgg-1 reaching a preconcentration factor (PF) of 160. A detection limit (3σ) of 0.7ngL-1 was achieved, when using only 3.0mg of substrate. Interferences affecting Bi(III) signal were carefully studied. Precision, expressed as relative standard deviation (RSD) turned to be 1.5% at the 0.1μgL-1 level (n=10). Accuracy test for the entire analytical procedure was performed by means of the Standard Reference Material (SRM) NIST 1643e (trace elements in water) and results were in good agreement with the certified values. The system was evaluated for quantitative determination of Bi(III) in different categories of waters.Fil: Parodi, Maria Belen. Universidad Nacional de San Martín. Instituto de Investigación en Ingeniería Ambiental; Argentina. Instituto Nacional de Tecnología Industrial; ArgentinaFil: Londonio, Juan Agustín. Universidad Nacional de San Martín. Instituto de Investigación en Ingeniería Ambiental; Argentina. Comisión Nacional de Energía Atómica; ArgentinaFil: Polla, Griselda Ines. Comisión Nacional de Energía Atómica; ArgentinaFil: Smichowski, Patricia Nora. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica; Argentin

On-line flow injection solid phase extraction using oxidised carbon nanotubes as the substrate for cold vapour-atomic absorption determination of Hg(II) in different kinds of water

A study was carried out to investigate the concentrations of Hg(II) in different categories of water samples at ng L1 levels. The capabilities of oxidised carbon nanotubes (ox-CNTs) were studied to assess if this substrate serves as an efficient material for Hg(II) preconcentration using an on-line flow injection cold vapour-atomic absorption spectrometry (FI-CV-AAS) system. Carbon nanotubes are characterized by a marked tendency to aggregate, which negatively affects the retention of Hg whenever integrated in flow systems as a packed column. For this reason, the preconcentration was carried out in a microcolumn filled with a mixture of ox-CNTs and a low molecular weight polyethylene. The preparation of the microcolumn was studied in detail. Concerning column design, the best performance was achieved when packing the substrate in a microcolumn of 2.25 mm (i.d.) 20 mm length. The effect of chemical and physical parameters including the pH of the solutions, the eluent type and the concentration was systematically examined. Mercury was retained at pH 5.0 and 15% (v/v) HCl was the best alternative for Hg(II) elution. Under optimal conditions, the adsorption capacity of the substrate was found to be 3.2 mg g1 reaching a preconcentration factor (PF) of 150. The high adsorption capacity of this substrate allowed reaching a detection limit (3s) of 1.9 ng L1, when using a sorbent column containing only 1.0 mg of ox-CNTs. The limit of quantification (10s) resulted to be 6.3 ng L1. Precision, expressed as relative standard deviation (RSD), turned out to be 1.6% at the 0.1 mg L1 level (n ¼ 8). The system was evaluated for quantitative determination of Hg in river water, sea water and effluents.Fil: Parodi, Maria Belen. Instituto Nacional de Tecnología Industrial; Argentina. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Londonio, Juan Agustín. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental; Argentina. Comisión Nacional de Energía Atómica. Gerencia Química. CAC; ArgentinaFil: Polla, Griselda Ines. Comisión Nacional de Energía Atómica; ArgentinaFil: Savio, Marianela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Química de San Luis. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Química de San Luis; Argentina. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Departamento de Química. Área de Química Analítica; ArgentinaFil: Smichowski, Patricia Nora. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Gerencia Química. CAC; Argentin

Design, fabrication and metrological evaluation of wearable pressure sensors

Pressure sensors are valuable transducers that are necessary in a huge number of medical application. However, the state of the art of compact and lightweight pressure sensors with the capability of measuring the contact pressure between two surfaces (contact pressure sensors) is very poor. In this work, several types of wearable contact pressure sensors are fabricated using different conductive textile materials and piezo-resistive films. The fabricated sensors differ in size, the textile conductor used and/or the number of layers of the sandwiched piezo-resistive film. The intention is to study, through the obtaining of their calibration curves, their metrological properties (repeatability, sensitivity and range) and determine which physical characteristics improve their ability for measuring contact pressures. It has been found that it is possible to obtain wearable contact pressure sensors through the proposed fabrication process with satisfactory repeatability, range and sensitivity; and that some of these properties can be improved by the physical characteristics of the sensors.Fil: Goy, Carla Belen. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; ArgentinaFil: Menichetti, Verónica. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Bioingeniería; ArgentinaFil: Yanicelli, Lucía María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; ArgentinaFil: Lucero, Javier Bernardo. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Gomez Lopez, Maria de Los Angeles. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Bioingeniería; ArgentinaFil: Parodi, Nicolás Franco. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; ArgentinaFil: Herrera de Olivera, Myriam Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; Argentin

Diagnosis and management of asymptomatic bacteriuria in kidney transplant recipients: a survey of current practice in Europe

International audienceBackgroundAsymptomatic bacteriuria is frequent in kidney transplant recipients (KTRs). However, there is no consensus on diagnosis or management. We conducted a European survey to explore current practice related to the diagnosis and management of asymptomatic bacteriuria in adult KTRs.MethodsA panel of experts from the European Renal Association–European Dialysis Transplant Association/Developing Education Science and Care for Renal Transplantation in European States working group and the European Study Group for Infections in Compromised Hosts of the European Society of Clinical Microbiology and Infectious Diseases designed this cross-sectional, questionnaire-based, self-administered survey. Invitations to participate were e-mailed to European physicians involved in the care of KTRs.ResultsTwo hundred and forty-four participants from 138 institutions in 25 countries answered the survey (response rate 30%). Most participants [72% (176/244)] said they always screen for asymptomatic bacteriuria in KTRs. Six per cent (15/240) reported never treating asymptomatic bacteriuria with antibiotics. When antimicrobial treatment was used, 24% of the participants (53/224) said they would start with empirical antibiotics. For an episode of asymptomatic bacteriuria caused by a fully susceptible microorganism and despite no contraindications, a majority of participants (121/223) said they would use a fluoroquinolone (n = 56), amoxicillin/clavulanic acid (n = 38) or oral cephalosporins (n = 27).ConclusionsScreening for and treating asymptomatic bacteriuria are common in KTRs despite uncertainties around the benefits and harms. In an era of antimicrobial resistance, further studies are needed to address the diagnosis and management of asymptomatic bacteriuria in these patients

Evaluation of a quality improvement intervention to reduce anastomotic leak following right colectomy (EAGLE): pragmatic, batched stepped-wedge, cluster-randomized trial in 64 countries

Background Anastomotic leak affects 8 per cent of patients after right colectomy with a 10-fold increased risk of postoperative death. The EAGLE study aimed to develop and test whether an international, standardized quality improvement intervention could reduce anastomotic leaks. Methods The internationally intended protocol, iteratively co-developed by a multistage Delphi process, comprised an online educational module introducing risk stratification, an intraoperative checklist, and harmonized surgical techniques. Clusters (hospital teams) were randomized to one of three arms with varied sequences of intervention/data collection by a derived stepped-wedge batch design (at least 18 hospital teams per batch). Patients were blinded to the study allocation. Low- and middle-income country enrolment was encouraged. The primary outcome (assessed by intention to treat) was anastomotic leak rate, and subgroup analyses by module completion (at least 80 per cent of surgeons, high engagement; less than 50 per cent, low engagement) were preplanned. Results A total 355 hospital teams registered, with 332 from 64 countries (39.2 per cent low and middle income) included in the final analysis. The online modules were completed by half of the surgeons (2143 of 4411). The primary analysis included 3039 of the 3268 patients recruited (206 patients had no anastomosis and 23 were lost to follow-up), with anastomotic leaks arising before and after the intervention in 10.1 and 9.6 per cent respectively (adjusted OR 0.87, 95 per cent c.i. 0.59 to 1.30; P = 0.498). The proportion of surgeons completing the educational modules was an influence: the leak rate decreased from 12.2 per cent (61 of 500) before intervention to 5.1 per cent (24 of 473) after intervention in high-engagement centres (adjusted OR 0.36, 0.20 to 0.64; P < 0.001), but this was not observed in low-engagement hospitals (8.3 per cent (59 of 714) and 13.8 per cent (61 of 443) respectively; adjusted OR 2.09, 1.31 to 3.31). Conclusion Completion of globally available digital training by engaged teams can alter anastomotic leak rates. Registration number: NCT04270721 (http://www.clinicaltrials.gov)