7,006 research outputs found
Left Atrial Appendage Volume As a New Predictor of Atrial Fibrillation Recurrence After Catheter Ablation
PURPOSE:
Recurrence of atrial fibrillation (AF) after catheter ablation is common, being clinically relevant to identify predictors of recurrence. The left atrial appendage (LAA) role as an AF trigger is scarcely explored. Our aim was to identify if LAA volume is an independent predictor of AF recurrence after catheter ablation.
METHODS:
We analysed 52 patients (aged 54 ± 10 years, 58% male) with paroxysmal and persistent AF who underwent a first AF catheter ablation and had performed contrast-enhanced cardiac computed tomography (CT) prior to the procedure.
RESULTS:
The mean left atrial and LAA volumes measured by cardiac CT were 98.9 ± 31.8 and 9.3 ± 3.5 mL, respectively. All patients received successful pulmonary vein isolation and were followed up for 24 months. AF recurrence occurred in 17 patients (33%). LAA volume was significantly greater in patients with AF recurrence than in those without recurrence (11.3 ± 2.9 vs. 8.2 ± 3.4 mL; p = 0.002). Multivariable analysis using Cox regression revealed that LAA volume (hazard ratio 1.32; 95% confidence interval 1.12-1.55; p = 0.001) and persistent AF (hazard ratio 4.22; 95% confidence interval 1.48-12.07; p = 0.007) were independent predictors for AF recurrence. An LAA volume greater than 8.825 mL predicted AF recurrence with 94% sensitivity and 66% specificity. The Kaplan-Meier analysis showed a lower rate free from AF recurrence in the group with an LAA volume >8.825 mL (p < 0.001).
CONCLUSIONS:
Larger LAA volume was associated with AF recurrence after catheter ablation in patients with paroxysmal and persistent AF.info:eu-repo/semantics/publishedVersio
B(1) inhomogeneity correction of RARE MRI with transceive surface radiofrequency probes
PURPOSE: The use of surface radiofrequency (RF) coils is common practice to boost sensitivity in (pre)clinical MRI. The number of transceive surface RF coils is rapidly growing due to the surge in cryogenically cooled RF technology and ultrahigh‐field MRI. Consequently, there is an increasing need for effective correction of the excitation field (B(1)(+)) inhomogeneity inherent in these coils. Retrospective B(1) correction permits quantitative MRI, but this usually requires a pulse sequence‐specific analytical signal intensity (SI) equation. Such an equation is not available for fast spin‐echo (Rapid Acquisition with Relaxation Enhancement, RARE) MRI. Here we present, test, and validate retrospective B(1) correction methods for RARE. METHODS: We implemented the commonly used sensitivity correction and developed an empirical model‐based method and a hybrid combination of both. Tests and validations were performed with a cryogenically cooled RF probe and a single‐loop RF coil. Accuracy of SI quantification and T(1) contrast were evaluated after correction. RESULTS: The three described correction methods achieved dramatic improvements in B(1) homogeneity and significantly improved SI quantification and T(1) contrast, with mean SI errors reduced from >40% to >10% following correction in all cases. Upon correction, images of phantoms and mouse heads demonstrated homogeneity comparable to that of images acquired with a volume resonator. This was quantified by SI profile, SI ratio (error 80% in vivo and ex vivo compared to PIU > 87% with the reference RF coil). CONCLUSIONS: This work demonstrates the efficacy of three B(1) correction methods tailored for transceive surface RF probes and RARE MRI. The corrected images are suitable for quantification and show comparable results between the three methods, opening the way for T(1) measurements and X‐nuclei quantification using surface transceiver RF coils. This approach is applicable to other MR techniques for which no analytical SI exists
New Generation of MOF-Monoliths Based on Metal Foams
Herein, it has been developed a method to prepare metallic foams starting from Zamak5 (ZnAlCu alloy) with different pore sizes. The Zamak5 metallic foam is designed to serve as a support and metallic precursor of ZIF-8. In this way, composite materials MOF-metal can be prepared, these composites have a large number of application in energy exchange processe such as: adsorption or chemical reactions. Additionally, this method of sythesizing MOFs is environmentally friendly thanks to absence of solvents. Hanerssing the low melting point of the linker, the linker is infiltrated into the foam where the foam and the linker react to form the ZIF-8. In this way we have managed to transform part of the foam into ZIF-8 crystals that remain adhered to the foam. The foams have been characterized and modeled studying the mechanical and electrical properties, finding that both can be predected by various models. Among these, Ashby and Mortensen models for mechanical properties and Ashby and Percolation model for electrical properties stand.The authors would like to acknowledge the financial support from “Ministerio de Ciencia e innovación” (PID2020-116998RB-I00) and Ministerio de Economía y Empresa (MAT2017-86992-R) and action Mobility of Alicante University
Análise rápida do uso da terra em região tradicional de cana-de-açúcar do estado de Alagoas.
O trabalho teve como objetivo levantar e analisar preliminarmente possíveis mudanças de uso da terra nos municípios de cultivo tradicional de cana-de-açúcar, bem como do seu entorno, dentro do estado de Alagoas. Foram levantados dados secundários de fontes oficiais e consultas bibliográficas, sendo avaliada a área plantada (ha) com: a) a cana-de-açúcar e b) milho + mandioca + feijão, no período de 2002 e 2007. Os resultados permitem inferir que as alterações no uso da terra são constantes dentro de Alagoas. Entretanto, ainda são necessários estudos mais aprofundados para se afirmar com propriedade à situação real de possível competição entre a cultura da cana-de-açúcar e a produção de alimentos, bem como sua relação com as áreas de pastagens, em Alagoas
Technical Developments and Ex Vivo Demonstration in a Mouse Model of Neuroinflammation
Neuroinflammation can be monitored using fluorine-19 (19F)-containing
nanoparticles and 19F MRI. Previously we studied neuroinflammation in
experimental autoimmune encephalomyelitis (EAE) using room temperature (RT)
19F radiofrequency (RF) coils and low spatial resolution 19F MRI to overcome
constraints in signal-to-noise ratio (SNR). This yielded an approximate
localization of inflammatory lesions. Here we used a new 19F transceive
cryogenic quadrature RF probe (19F-CRP) that provides the SNR necessary to
acquire superior spatially-resolved 19F MRI. First we characterized the
signal-transmission profile of the 19F-CRP. The 19F-CRP was then benchmarked
against a RT 19F/1H RF coil. For SNR comparison we used reference compounds
including 19F-nanoparticles and ex vivo brains from EAE mice administered with
19F-nanoparticles. The transmit/receive profile of the 19F-CRP diminished with
increasing distance from the surface. This was counterbalanced by a
substantial SNR gain compared to the RT coil. Intraparenchymal inflammation in
the ex vivo EAE brains was more sharply defined when using 150 μm isotropic
resolution with the 19F-CRP, and reflected the known distribution of EAE
histopathology. At this spatial resolution, most 19F signals were undetectable
using the RT coil. The 19F-CRP is a valuable tool that will allow us to study
neuroinflammation with greater detail in future in vivo studies
RAPID-retargetability for reusability of application-driven quadrature D/A interface block design
This paper describes ESPRIT 29648, concerning the development of an advanced methodology for the design of a mixed-signal application-driven quadrature D/A interface sub-system, aiming at its reusability by a retargetting procedure with minimal changes to their structural sub-blocks. The methodology is demonstrated, first, by developing a nominal design platform for the implementation in 0.35 /spl mu/m double-poly CMOS technology of a quadrature D/A interface block design for the GSM standard, and, then, by an automatic retargeting in an evolutionary technology through the realization of a silicon prototype in 0.25 /spl mu/m CMOS.European Community 2964
Health and living conditions in social housing: comparison between rehabilitated and non-rehabilitated neighbourhoods
Aim: Our aim is to compare how residents from two social housing neighbourhoods of Porto City, one rehabilitated and one non-rehabilitated, perceived their living conditions, health and quality of life.
Subjects and methods: A cross-sectional study was conducted, selecting residents from two social housing neighbourhoods of Porto City, one rehabilitated and another one non-rehabilitated. The information was collected through quantitative (a structured questionnaire; n = 82) and qualitative face-to-face interviews administered by trained interviewers (n = 16).
Results: No significant differences were found between populations from both neighbourhoods regarding social, behavioural and health characteristics. The major differences among neighbourhoods were found on variables such as satisfaction with house, the need of rehabilitation work, and the absence of mould and dampness in the house (p < 0.001) as well as pollution (p < 0.05). Qualitative data showed that residents from the rehabilitated houses were pleased not to have been moved to another location and were very satisfied with the rehabilitation work, which in their perception contributed to the residents’ wellbeing. Nominal and ordinal variables were described using proportions and compared using the chi-square test. Quantitative continuous variables were presented as a median (percentile 25 to percentile 75) and they were compared via the Mann-Whitney test.
Conclusion: Public economic and financing resources should be redirected to social housing rehabilitation that, although in the short term does not have a direct impact on health savings for the occupants, is an important dimension of the residents’ sense of wellbeing and satisfaction
SME’s perspective on psychosocial risks: From identifying to intervening in four countries
Introduction: Certain aspects of the work design or the organization as well as the social context of work may lead to negative physical, psychological and social outcomes. These aspects are considered psychosocial risks. Portugal, Spain, Italy, and Greece are facing the biggest consequences of the economic crisis with psychosocial risks being exacerbated. In these countries, small and medium enterprises play an important role in the economy. This paper presents the quantitative data from the project, collected in those four countries. The main goal of the survey was to determine the SMEs’ perspective about emergent psychosocial risks, difficulties and concerns related to its prevention as well as to assess their knowledge and existing practices regarding psychosocial risks prevention.info:eu-repo/semantics/publishedVersio
Extreme Starbursts in the Local Universe
The "Extreme starbursts in the local universe" workshop was held at the
Insituto de Astrofisica de Andalucia in Granada, Spain on 21-25 June 2010.
Bearing in mind the advent of a new generation of facilities such as JWST,
Herschel, ALMA, eVLA and eMerlin, the aim of the workshop was to bring together
observers and theorists to review the latest results. The purpose of the
workshop was to address the following issues: what are the main modes of
triggering extreme starbursts in the local Universe? How efficiently are stars
formed in extreme starbursts? What are the star formation histories of local
starburst galaxies? How well do the theoretical simulations model the
observations? What can we learn about starbursts in the distant Universe
through studies of their local counterparts? How important is the role of
extreme starbursts in the hierarchical assembly of galaxies? How are extreme
starbursts related to the triggering of AGN in the nuclei of galaxies? Overall,
41 talks and 4 posters with their corresponding 10 minutes short talks were
presented during the workshop. In addition, the workshop was designed with
emphasis on discussions, and therefore, there were 6 discussion sessions of up
to one hour during the workshop. Here is presented a summary of the purposes of
the workshop as well as a compilation of the abstracts corresponding to each of
the presentations. The summary and conclusions of the workshop along with a
description of the future prospects by Sylvain Veilleux can be found in the
last section of this document. A photo of the assistants is included.Comment: worksho
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