Control of a multi-axis platform for metrological purposes using diferential flatness

Positioning and tracking devices with micrometer range and sub-micrometer resolution are becoming of special interest in recent years for an extending range of applications including metrological devices, manipulators and mechanization systems both in research and high precision industries (for example, semiconductors). The control of these systems is not an easy task because of its normally high stiffness and the coupling existing between the different degrees of freedom. The present work proposes a control strategy based on differential flatness for static positioning and dynamic trajectory tracking with a platform of three degrees of freedom. The system uses piezoelectric actuators and is specially conceived for metrological devices, which do not suffer important external loads. The proposed method permits to decouple the design of a closed loop control for each degree of freedom and calculates an open loop command directly from the trajectory definition in the three degrees of freedom. The performance of the controller has been experimentally checked both in positioning and tracking applications

Model-based mechanical and control design of a three-axis platform

In recent times, the interest from scientific and industrial community for the micrometric range has observed an important growth. The advances in microelectronics or the research on microbiology are just two examples of fields requiring technologies capable of assuring accurate displacements in that range. The present work focuses on the mechanical and control design of a micrometer range positioning and tracking platform using mathematical models. In a first phase, these models permit to identify the relationship between the dynamic performance of the structure and the mechanical properties of the elements that compose it. At the very beginning of the design, this information is used for the development of the different parts of the platform. Afterwards, once an initial design is finished and 3D models are available, the design is refined using finite element tools. In parallel to the mechanical design, the knowledge of the system embodied in the mathematical model is profited in the design of a control strategy for tracking and positioning. The proposed control strategy combines a linear controller based on differential flatness with a hysteresis compensator for correcting this nonlinear effect of the piezoelectric actuators. In the present paper, the mathematical derivation of the system model, its application to the design and validation of the platform and the final closed loop experimental evaluation are described

Efficacy and safety of a booster dose of influenza vaccination in solid organ transplant recipients, TRANSGRIPE 1-2: study protocol for a multicenter, randomized, controlled clinical trial

BACKGROUND: Despite administration of annual influenza vaccination, influenza-associated complications in transplant recipients continue to be an important cause of hospitalization and death. Although influenza vaccination has been proven to be the most effective measure to reduce influenza infection after transplantation, transplant recipients are still vulnerable to influenza infections, with lower serological responses to vaccination compared to the general population. In order to assess the efficacy and safety of an alternative immunization scheme for solid organ transplant recipients, the TRANSGRIPE1-2 Study Group aimed to test a booster dose administration 5 weeks after the standard vaccination. The primary objective of this trial was to compare short-term and long-term neutralizing antibody immunogenicity of a booster dose of influenza vaccination to the standard single-dose immunization scheme. Secondary objectives included the evaluation of the efficacy and/or safety, cellular immune response, incidence of influenza infection, graft rejection, retransplant and mortality rates. METHODS/DESIGN: This phase III, randomized, controlled, open-label clinical trial was conducted between October 2012 and December 2013 in 12 Spanish public referral hospitals. Solid organ transplant recipients (liver, kidney, heart or lung), older than 16 years of age more than 30 days after transplantation were eligible to participate. Patients (N = 514) were stratified 1:1 by center, type of organ and time after transplantation and who either received the standard single dose (n = 257) or were treated according to a novel influenza vaccination schedule comprising the administration of a booster dose 5 weeks after standard vaccination (n = 254). Seroconversion rates were measured as a determinant of protection against influenza (main outcome). Efficacy and safety outcomes were followed until 1 year after influenza vaccination with assessment of short-term (0, 5, 10 and 15 weeks) and long-term (12 months) results. Intention-to-treat, per-protocol and safety analyses will be performed. DISCUSSION: This trial will increase knowledge about the safety and efficacy of a booster dose of influenza vaccine in solid organ transplant recipients. At the time the manuscript was submitted for publication, trial recruitment was closed with a total of 499 participants included during a 2-month period (within the seasonal influenza vaccination campaign). TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01761435 (registered 13 December 2012). EudraCT Identifier: 2011-003243-21 (registered 4 July 2011)

IFISTRATEGY: Spanish National Survey of Invasive Fungal Infection in Hemato-Oncologic Patients

Recent advances in the treatment of hematologic malignancies have improved the overall survival rate, but the number of patients at risk of developing an invasive fungal infection (IFI) has increased. Invasive infections caused by non-Candida albicans species, non-Aspergillus molds, and azole-resistant Aspergillus fumigatus have been increasingly reported in recent years. We developed a cross-sectional multicenter survey which involved a total of 55 hematologists and infectious disease specialists from a total of 31 Spanish hospitals, to determine the most frequent strategies used for the management of IFIs. Data collection was undertaken through an online survey which took place in 2022. Regarding key strategies, experts usually prefer early treatment for persistent febrile neutropenia, switching to another broad-spectrum antifungal family if azole-resistant Aspergillus is suspected, broad-spectrum azoles and echinocandins as prophylactic treatment in patients receiving midostaurin or venetoclax, and liposomal amphotericin B for breakthrough IFIs after prophylaxis with echinocandins in patients receiving new targeted therapies. For antifungals failing to reach adequate levels during the first days and suspected invasive aspergillosis, the most appropriate strategy would be to associate an antifungal from another family

Model-free control of a 3-DOF piezoelectric nanopositioning platform

A model-free controller is designed for a nanopositioning platform with three degrees of fredom. The system is specially difficult to control because of the coupling between the different movements and the hysteresis present in the piezoelectric actuators. The authors propose a control design methodology based in the so called ultra-local system description. The developed controller has been implemented and validated on a real test bench and it has proven a good performance in handling the nonlinearities and the uncertainties present in the platform

Is routine ophthalmoscopy really necessary in candidemic patients?

The purpose of this study was to determine among patients with candidemia the real rate of ophthalmoscopy and the impact of performing ocular assessment on the outcome of the disease. We performed a post hoc analysis of a prospective, multicenter, population-based candidemia surveillance program implemented in Spain during 2010-2011 (CANDIPOP). Ophthalmoscopy was performed in only 168 of the 365 patients with candidemia (46%). Ocular lesions related to candidemia were found in only 13/168 patients (7.7%), of whom 1 reported ocular symptoms (incidence of symptomatic disease in the whole population, 0.27% [1/365]). Ophthalmological findings led to a change in antifungal therapy in only 5.9% of cases (10/168), and performance of the test was not related to a better outcome. Ocular candidiasis was not associated with a worse outcome and progressed favorably in all but 1 evaluable patient, who did not experience vision loss. The low frequency of ophthalmoscopy and ocular involvement and the asymptomatic nature of ocular candidiasis, with a favorable outcome in almost all cases, lead us to reconsider the need for systematic ophthalmoscopy in all candidemic patients

Multivariate logistic regression analysis of prognostic factors associated with 30-day mortality.

<p>Multivariate logistic regression analysis of prognostic factors associated with 30-day mortality.</p

Efficacy and safety of a booster dose of influenza vaccination in solid organ transplant recipients, TRANSGRIPE 1-2: study protocol for a multicenter, randomized, controlled clinical trial.

TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT01761435 (registered 13 December 2012). EudraCT Identifier: 2011-003243-21 (registered 4 July 2011). Clinical Trial, Phase III; Comparative Study; Journal Article; Multicenter Study; Randomized Controlled Trial; Research Support, Non-U.S. Gov't;BACKGROUND Despite administration of annual influenza vaccination, influenza-associated complications in transplant recipients continue to be an important cause of hospitalization and death. Although influenza vaccination has been proven to be the most effective measure to reduce influenza infection after transplantation, transplant recipients are still vulnerable to influenza infections, with lower serological responses to vaccination compared to the general population. In order to assess the efficacy and safety of an alternative immunization scheme for solid organ transplant recipients, the TRANSGRIPE1-2 Study Group aimed to test a booster dose administration 5 weeks after the standard vaccination. The primary objective of this trial was to compare short-term and long-term neutralizing antibody immunogenicity of a booster dose of influenza vaccination to the standard single-dose immunization scheme. Secondary objectives included the evaluation of the efficacy and/or safety, cellular immune response, incidence of influenza infection, graft rejection, retransplant and mortality rates. METHODS/DESIGN This phase III, randomized, controlled, open-label clinical trial was conducted between October 2012 and December 2013 in 12 Spanish public referral hospitals. Solid organ transplant recipients (liver, kidney, heart or lung), older than 16 years of age more than 30 days after transplantation were eligible to participate. Patients (N = 514) were stratified 1:1 by center, type of organ and time after transplantation and who either received the standard single dose (n = 257) or were treated according to a novel influenza vaccination schedule comprising the administration of a booster dose 5 weeks after standard vaccination (n = 254). Seroconversion rates were measured as a determinant of protection against influenza (main outcome). Efficacy and safety outcomes were followed until 1 year after influenza vaccination with assessment of short-term (0, 5, 10 and 15 weeks) and long-term (12 months) results. Intention-to-treat, per-protocol and safety analyses will be performed. DISCUSSION This trial will increase knowledge about the safety and efficacy of a booster dose of influenza vaccine in solid organ transplant recipients. At the time the manuscript was submitted for publication, trial recruitment was closed with a total of 499 participants included during a 2-month period (within the seasonal influenza vaccination campaign).This study was funded by a research grant for the promotion of investigator-driven clinical research from the Ministry of Health, Social Policy and Equity of the Spanish Government (project number EC11-456).Ye

Multivariate logistic regression analysis of prognostic factors associated with 30-day mortality.

<p>Multivariate logistic regression analysis of prognostic factors associated with 30-day mortality.</p

Risk conditions for ocular candidiasis.

<p>Multivariate analysis.</p