860 research outputs found
Biological carbon dioxide utilisation in food waste anaerobic digesters
Carbon dioxide (CO2) enrichment of anaerobic digesters (AD) was previously identified as a potential on-site carbon revalorisation strategy. This study addresses the lack of studies investigating this concept in up-scaled units and the need to understand the mechanisms of exogenous CO2 utilisation. Two pilot-scale ADs treating food waste were monitored for 225 days, with the test unit being periodically injected with CO2 using a bubble column. The test AD maintained a CH4 production rate of 0.56 ± 0.13 m3 CH4·(kg VSfed d)−1 and a CH4 concentration in biogas of 68% even when dissolved CO2 levels were increased by a 3 fold over the control unit. An additional uptake of 0.55 kg of exogenous CO2 was achieved in the test AD during the trial period. A 2.5 fold increase in hydrogen (H2) concentration was observed and attributed to CO2 dissolution and to an alteration of the acidogenesis and acetogenesis pathways. A hypothesis for conversion of exogenous CO2 has been proposed, which requires validation by microbial community analysis
A Reproducible Protocol to Assess Arrhythmia Vulnerability in Silico: Pacing at the End of the Effective Refractory Period
In both clinical and computational studies, different pacing protocols are used to induce arrhythmia and non-inducibility is often considered as the endpoint of treatment. The need for a standardized methodology is urgent since the choice of the protocol used to induce arrhythmia could lead to contrasting results, e.g., in assessing atrial fibrillation (AF) vulnerabilty. Therefore, we propose a novel method—pacing at the end of the effective refractory period (PEERP)—and compare it to state-of-the-art protocols, such as phase singularity distribution (PSD) and rapid pacing (RP) in a computational study. All methods were tested by pacing from evenly distributed endocardial points at 1 cm inter-point distance in two bi-atrial geometries. Seven different atrial models were implemented: five cases without specific AF-induced remodeling but with decreasing global conduction velocity and two persistent AF cases with an increasing amount of fibrosis resembling different substrate remodeling stages. Compared with PSD and RP, PEERP induced a larger variety of arrhythmia complexity requiring, on average, only 2.7 extra-stimuli and 3 s of simulation time to initiate reentry. Moreover, PEERP and PSD were the protocols which unveiled a larger number of areas vulnerable to sustain stable long living reentries compared to RP. Finally, PEERP can foster standardization and reproducibility, since, in contrast to the other protocols, it is a parameter-free method. Furthermore, we discuss its clinical applicability. We conclude that the choice of the inducing protocol has an influence on both initiation and maintenance of AF and we propose and provide PEERP as a reproducible method to assess arrhythmia vulnerability
Non-Invasive and Quantitative Estimation of Left Atrial Fibrosis Based on P Waves of the 12-Lead ECG—A Large-Scale Computational Study Covering Anatomical Variability
The arrhythmogenesis of atrial fibrillation is associated with the presence of fibrotic atrial tissue. Not only fibrosis but also physiological anatomical variability of the atria and the thorax reflect in altered morphology of the P wave in the 12-lead electrocardiogram (ECG). Distinguishing between the effects on the P wave induced by local atrial substrate changes and those caused by healthy anatomical variations is important to gauge the potential of the 12-lead ECG as a non-invasive and cost-effective tool for the early detection of fibrotic atrial cardiomyopathy to stratify atrial fibrillation propensity. In this work, we realized 54,000 combinations of different atria and thorax geometries from statistical shape models capturing anatomical variability in the general population. For each atrial model, 10 different volume fractions (0–45%) were defined as fibrotic. Electrophysiological simulations in sinus rhythm were conducted for each model combination and the respective 12-lead ECGs were computed. P wave features (duration, amplitude, dispersion, terminal force in V1) were extracted and compared between the healthy and the diseased model cohorts. All investigated feature values systematically in- or decreased with the left atrial volume fraction covered by fibrotic tissue, however value ranges overlapped between the healthy and the diseased cohort. Using all extracted P wave features as input values, the amount of the fibrotic left atrial volume fraction was estimated by a neural network with an absolute root mean square error of 8.78%. Our simulation results suggest that although all investigated P wave features highly vary for different anatomical properties, the combination of these features can contribute to non-invasively estimate the volume fraction of atrial fibrosis using ECG-based machine learning approaches
Effect of cationic chemical disorder on defect formation energies in uranium-plutonium mixed oxides
At the atomic scale, uranium-plutonium mixed oxides (U,Pu)O_2 are
characterized by cationic chemical disorder, which entails that U and Pu
cations are randomly distributed on the cation sublattice. In the present work,
we study the impact of disorder on point-defect formation energies in (U,Pu)O_2
using interatomic-potential and Density Functional Theory (DFT+U) calculations.
We focus on bound Schottky defects (BSD) that are among the most stable defects
in these oxides. As a first step, we estimate the distance R_D around the BSD
up to which the local chemical environment significantly affects their
formation energy. To this end, we propose an original procedure in which the
formation energy is computed for several supercells at varying levels of
disorder. We conclude that the first three cation shells around the BSD have a
non-negligible influence on their formation energy (R_{D} = 7.0 \{AA}). We
apply then a systematic approach to compute the BSD formation energies for all
the possible cation configurations on the first and second nearest neighbor
shells around the BSD. We show that the formation energy can range in an
interval of 0.97 eV, depending on the relative amount of U and Pu neighboring
cations. Based on these results, we propose an interaction model that describes
the effect of nominal and local composition on the BSD formation energy.
Finally, the DFT+U benchmark calculations show a satisfactory agreement for
configurations characterized by a U-rich local environment, and a larger
mismatch in the case of a Pu-rich one. In summary, this work provides valuable
insights on the properties of BSD defects in (U,Pu)O_2, and can represent a
valid strategy to study point defect properties in disordered compounds.Comment: 33 pages, 20 figure
Severity and Phenotype of Bullous Pemphigoid Relate to Autoantibody Profile Against the NH2- and COOH-Terminal Regions of the BP180 Ectodomain
Bullous pemphigoid, the most common autoimmune subepidermal bullous disorder, is associated with autoantibodies targeting antigenic sites clustered within the extracellular domain of BP180. To investigate epitope and subclass specificity of autoantibodies in bullous pemphigoid, we developed an enzyme-linked immunosorbent assay utilizing baculovirus-expressed recombinant forms of the NH2- and COOH-terminal regions of the extracellular domain of BP180 and examined sera obtained from patients with active bullous pemphigoid (n=116) and controls (n=100). Ninety-three (80%) and 54 (47%) of the 116 bullous pemphigoid sera recognized the NH2- and COOH-terminal regions, respectively, of the extracellular domain of BP180. Detailed analysis demonstrates that (i) this novel enzyme-linked immunosorbent assay is highly specific (98%) and sensitive (93%) as 108 of 116 bullous pemphigoid sera reacted with at least one of the baculovirus-derived recombinants, (ii) in active bullous pemphigoid, autoantibodies against the NH2-terminus of the extracellular domain of BP180 were predominantly of the IgG1 class, whereas a dual IgG1 and IgG4 response to this region was related to a more severe skin involvement, (iii) autoreactivity against both the NH2- and COOH-terminal regions was more frequently detected in patients with mucosal lesions, and (iv) levels of IgG (and IgG1) against the NH2-terminal, but not against the COOH-terminal portion of the extracellular domain of BP180, reflected disease severity indicating that autoantibodies against the NH2-terminus are critical in the pathogenesis of bullous pemphigoid. In conclusion, this novel enzyme-linked immunosorbent assay represents a highly sensitive and specific assay for rapid diagnosis of bullous pemphigoid and related disorders and may provide predictive parameters for the management of bullous pemphigoid patients
Efeitos do treino multicomponente na força de sobreviventes do cancro de mama
Cancro de mama representa 30% de ocorrência dentre todos tipos de cancros no sexo feminino. Como consequência do tratamento existe uma diminuição da força muscular, que leva a diminuição da qualidade de vida e de limitações na realização de atividade da vida diária (AVDs), principalmente no local afetado pelo cancro. Com o exercÃcio fÃsico, é possÃvel em termos de efeitos fisiológicos, a melhoria da força muscular. Objetivos: Analisar os efeitos de 36 semanas de treino multicomponente (TMC), na força e resistência dos membros inferiores (MI) e superiores [(MS) braço não-intervencionado e braço intervencionado], de mulheres sobreviventes do cancro de mama. Métodos: Este foi um estudo quase-experimental, em que participaram 8 mulheres sobreviventes do cancro de mama, com idade de 64 ± 8,6 anos, peso corporal de 73,1 ± 12,2 quilogramas, altura de 1,63 ± 0,07 metros, Ãndice de massa corporal (IMC) 27,4 ± 2,8. O TMC foi realizado durante 36 semanas no Instituto Politécnico de Bragança, no programa de exercÃcio fÃsico Rosa Ativo, 3 vezes por semana, com sessões de 60 minutos cada. Resultados: Após 36 semanas de TMC, observamos melhoras na Força de MS no braço não-intervencionado, obtivemos valores incrementais de 105%; para Força de MSint no braço intervencionado obtivemos valores incrementais de 185%; para Força de MI obtivemos valores incrementais de 45%, p < 0,05. Conclusão: 36 semanas de TMC foram eficientes na melhora da força muscular de mulheres sobreviventes do cancro de mama.info:eu-repo/semantics/publishedVersio
a prospective observational study
Introduction Emergency rooms (ERs) generally assign a preliminary diagnosis to
patients, who are then hospitalised and may subsequently experience a change
in their lead diagnosis (cDx). In ERs, the cDx rate varies from around 15% to
more than 50%. Among the most frequent reasons for diagnostic errors are
cognitive slips, which mostly result from faulty data synthesis. Furthermore,
physicians have been repeatedly found to be poor self-assessors and to be
overconfident in the quality of their diagnosis, which limits their ability to
improve. Therefore, some of the clinically most relevant research questions
concern how diagnostic decisions are made, what determines their quality and
what can be done to improve them. Research that addresses these questions is,
however, still rare. In particular, field studies that allow for generalising
findings from controlled experimental settings are lacking. The ER, with its
high throughput and its many simultaneous visits, is perfectly suited for the
study of factors contributing to diagnostic error. With this study, we aim to
identify factors that allow prediction of an ER's diagnostic performance.
Knowledge of these factors as well as of their relative importance allows for
the development of organisational, medical and educational strategies to
improve the diagnostic performance of ERs. Methods and analysis We will
conduct a field study by collecting diagnostic decision data, physician
confidence and a number of influencing factors in a real-world setting to
model real-world diagnostic decisions and investigate the adequacy, validity
and informativeness of physician confidence in these decisions. We will
specifically collect data on patient, physician and encounter factors as
predictors of the dependent variables. Statistical methods will include
analysis of variance and a linear mixed-effects model. Ethics and
dissemination The Bern ethics committee approved the study under KEK Number
197/15. Results will be published in peer-reviewed scientific medical
journals. Authorship will be determined according to ICMJE guidelines. Trial
registration number The study protocol Version 1.0 from 17 May 2015 is
registered in the Inselspital Research Database Information System (IRDIS) and
with the IRB (‘Kantonale Ethikkomission’) Bern under KEK Number 197/15
Machine learning enables noninvasive prediction of atrial fibrillation driver location and acute pulmonary vein ablation success using the 12-lead ECG
Background: Atrial fibrillation (AF) is the most common supraventricular arrhythmia, characterized by disorganized atrial electrical activity, maintained by localized arrhythmogenic atrial drivers. Pulmonary vein isolation (PVI) allows to exclude PV-related drivers. However, PVI is less effective in patients with additional extra-PV arrhythmogenic drivers.
Objectives: To discriminate whether AF drivers are located near the PVs vs extra-PV regions using the noninvasive 12-lead electrocardiogram (ECG) in a computational and clinical framework, and to computationally predict the acute success of PVI in these cohorts of data.
Methods: AF drivers were induced in 2 computerized atrial models and combined with 8 torso models, resulting in 1128 12-lead ECGs (80 ECGs with AF drivers located in the PVs and 1048 in extra-PV areas). A total of 103 features were extracted from the signals. Binary decision tree classifier was trained on the simulated data and evaluated using hold-out cross-validation. The PVs were subsequently isolated in the models to assess PVI success. Finally, the classifier was tested on a clinical dataset (46 patients: 23 PV-dependent AF and 23 with additional extra-PV sources).
Results: The classifier yielded 82.6% specificity and 73.9% sensitivity for detecting PV drivers on the clinical data. Consistency analysis on the 46 patients resulted in 93.5% results match. Applying PVI on the simulated AF cases terminated AF in 100% of the cases in the PV class.
Conclusion: Machine learning–based classification of 12-lead-ECG allows discrimination between patients with PV drivers vs those with extra-PV drivers of AF. The novel algorithm may aid to identify patients with high acute success rates to PVI
Projeto Rosa Ativo: programa de exercÃcio fÃsico regular para doentes oncológicos
O cancro da mama é o cancro com maior prevalência no sexo feminino em Portugal, sendo também a principal causa das mortes por neoplasia nas mulheres. Tendo em conta a importância os efeitos preventivos e protetores do exercÃcio fÃsico nesta população especial, será desenvolvido o projeto Rosa Ativo, um programa de exercÃcio fÃsico para doentes oncológicos, no Instituto Politécnico de Bragança (IPB), com a colaboração dos centros de saúde de Bragança, da Liga Portuguesa Contra o Cancro e da Unidade Local de Saúde. Objetivos: Avaliar, prescrever e orientar a prática de exercÃcio fÃsico individualizado para doentes oncológicos antes e após intervenção cirúrgica/tratamento. Métodos: A amostra será composta por um grupo de intervenção de sobreviventes de cancro de mama, 2 vezes por semana, com duração de 50 minutos cada sessão, e grupo de controlo de sobreviventes de cancro mama fisicamente inativas. Será avaliada a aptidão funcional através do Functional Fitness Test: a força e a resistência dos membros superioers (MS) e inferiores (MI) , a flexibilidade dos MI e MS, a agilidade e o equilÃbrio dinâmico, a resistência aeróbia; a composição corporal : o Ãndice de massa corporal, a densidade mineral óssea, a massa magra (MM) e a percentagem de gordura corporal; a qualidade de vida, a qualidade do sono, o risco para sintomas de depressão Resultados esperados: Esperamos melhorias positivas e significativas na capacidade funcional, qualidade de vida, qualidade do sono, Ãndices de depressão, bem-estar, e auxiliar no eficiência no tratamento do cancro nas participantes do projeto.info:eu-repo/semantics/publishedVersio
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