Dielectric relaxation dynamics of high-temperature piezoelectric polyimide copolymers

Polyimide co-polymers have been prepared based on different diamines as co-monomers: a diamine without CN groups and a novel synthesized diamine with two CN groups prepared by polycondensation reaction followed by thermal cyclodehydration. Dielectric spectroscopy measurements were performed and the dielectric complex function, ac conductivity and electric modulus of the co-polymers were investigated as a function of CN group content in the frequency range from 0.1 Hz to 107 Hz at temperatures from 25 to 260 °C. For all samples and temperatures above 150ºC, the dielectric constant increases with increasing temperature due to increaseing conductivity. The α-relaxation is just detected for the sample without CN groups, being this relaxation overlapped by the electrical conductivity contributions in the remaining samples. For the copolymer samples and the polymer with CN groups an important Maxwell-Wagner-Sillars contribution is detected. The mechanisms responsible for the dielectric relaxation, conduction process and electric modulus response have been discussed as a function of the CN groups content present in the samples.This work was supported by FEDER through the COMPETE Program and by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Project PESTC/FIS/UI607/2011 and grants SFRH/BD/ 62507/2009 (A.C.L.) SFRH/BD/68499/2010 (C.M.C.). The authors also thank funding from “Matepro – Optimizing Materials and Processes”, ref. NORTE-07-0124-FEDER-000037”, co-funded by the “Programa Operacional Regional do Norte” (ON.2 – O Novo Norte), under the “Quadro de Referência Estratégico Nacional” (QREN), through the “Fundo Europeu de Desenvolvimento Regional” (FEDER). RSS acknowledge the support of the Spanish Ministry of Economy and Competitiveness through the project MAT2012-38359-C03-01 (including the FEDER financial support). Authors also thank the Basque Country Government for financial support (ACTIMAT project, ETORTEK Program, IE13-380, and Ayudas para Grupos de Investigación del Sistema Universitario Vasco Program, IT718-13)

Wean Earlier and Automatically with New technology (the WEAN study): a protocol of a multicentre, pilot randomized controlled trial

<p>Abstract</p> <p>Background</p> <p>Weaning is the process during which mechanical ventilation is withdrawn and the work of breathing is transferred from the ventilator back to the patient. Prolonged weaning is associated with development of ventilator-related complications and longer stays in the Intensive Care Unit (ICU). Computerized or Automated Weaning is a novel weaning strategy that continuously measures and adapts ventilator support (by frequently measuring and averaging three breathing parameters) and automatically conducts Spontaneous Breathing Trials to ascertain whether patients can resume autonomous breathing. Automated Weaning holds promise as a strategy to reduce the time spent on the ventilator, decrease ICU length of stay, and improve clinically important outcomes.</p> <p>Methods/Design</p> <p>A pilot weaning randomized controlled trial (RCT) is underway in the ICUs of 8 Canadian hospitals. We will randomize 90 critically ill adults requiring invasive ventilation for at least 24 hours and identified at an early stage of the weaning process to either Automated Weaning (SmartCare™) or Protocolized Weaning. The results of a National Weaning Survey informed the design of the Protocolized Weaning arm. Both weaning protocols are operationalized in Pressure Support mode, include opportunities for Spontaneous Breathing Trials, and share a common sedation protocol, oxygen titration parameters, and extubation and reintubation criteria. The primary outcome of the WEAN study is to evaluate compliance with the proposed weaning and sedation protocols. A key secondary outcome of the pilot RCT is to evaluate clinician acceptance of the weaning and sedation protocols. Prior to initiating the WEAN Study, we conducted a run-in phase, involving two patients per centre (randomizing the first participant to either weaning strategy and assigning the second patient to the alternate strategy) to ensure that participating centres could implement the weaning and sedation protocols and complete the detailed case report forms.</p> <p>Discussion</p> <p>Mechanical ventilation studies are difficult to implement; requiring protocols to be operationalized continuously and entailing detailed daily data collection. As the first multicentre weaning RCT in Canada, the WEAN Study seeks to determine the feasibility of conducting a large scale future weaning trial and to establish a collaborative network of ICU clinicians dedicated to advancing the science of weaning.</p> <p>Trial Registration Number</p> <p>ISRCTN43760151</p

Association of Postoperative High-Sensitivity Troponin Levels With Myocardial Injury and 30-Day Mortality Among Patients Undergoing Noncardiac Surgery

Non-commercial use only. Funding for this study came from more than 60 grants for VISION and its substudies. Canada: Canadian Institutes of Health Research (7 grants); Heart and Stroke Foundation of Ontario (2 grants); Academic Health Science Centres Alternative Funding Plan Innovation Fund Ontario; Population Health Research Institute; CLARITY Research Group; McMaster University Department of Surgery Surgical Associates; Hamilton Health Science New Investigator Fund; Hamilton Health Sciences; Ontario Ministry of Resource and Innovation; Stryker Canada; McMaster University, Department of Anesthesiology (2 grants); St Joseph’s Healthcare, Department of Medicine (2 grants); Father Sean O’Sullivan Research Centre (2 grants); McMaster University Department of Medicine (2 grants); Roche Diagnostics Global Office (5 grants); Hamilton Health Sciences Summer Studentships (6 grants); McMaster University Department of Clinical Epidemiology and Biostatistics; McMaster University, Division of Cardiology; Canadian Network and Centre for Trials Internationally; Winnipeg Health Sciences Foundation; University of Manitoba Department of Surgery (2 grants); Diagnostic Services of Manitoba Research; Manitoba Medical Services Foundation; Manitoba Health Research Council; University of Manitoba Faculty of Dentistry Operational Fund; University of Manitoba Department of Anesthesia; University Medical Group, Department of Surgery, University of Manitoba, Start-up Fund. Australia: National Health and Medical Research Council Program. Brazil: Projeto Hospitais de Excelência a Serviço do SUS (PROADI-SUS) grant from the Brazilian Ministry of Health in partnership with Hcor (Cardiac Hospital Sao Paulo–SP); National Council for Scientific and Technological Development (CNPq) grant from the Brazilian Ministry of Science and Technology. China: Public Policy Research Fund (grant CUHK-4002-PPR-3), Research Grant Council, Hong Kong SAR; General Research Fund (grant 461412), Research Grant Council, Hong Kong SAR; Australian and New Zealand College of Anaesthetists (grant 13/008). Colombia: School of Nursing, Universidad Industrial de Santander; Grupo de Cardiología Preventiva, Universidad Autónoma de Bucaramanga; Fundación Cardioinfantil–Instituto de Cardiología; Alianza Diagnóstica SA. France: Université Pierre et Marie Curie, Département d’anesthésie Réanimation, Pitié-Salpêtrière, Assistance Publique–Hôpitaux de Paris. India: St John’s Medical College and Research Institute; Division of Clinical Research and Training. Malaysia: University of Malaya (grant RG302-14AFR); University of Malaya, Penyelidikan Jangka Pendek. Poland: Polish Ministry of Science and Higher Education (grant NN402083939). South Africa: University of KwaZulu-Natal. Spain: Instituto de Salud Carlos III; Fundació La Marató de TV3. United States: American Heart Association; Covidien. United Kingdom: National Institute for Health Researc