32 research outputs found
Value of Lung Ultrasound Sonography B-Lines Quantification as a Marker of Heart Failure in COPD Exacerbation
Fadwa Lajili,1,2 Marwa Toumia,1,2 Adel Sekma,1,2 Khaoula Bel Haj Ali,1,2 Sarra Sassi,1,2 Asma Zorgati,3 Hajer Yaakoubi,3 Rym Youssef,3 Mohamed Habib Grissa,1,2 Kaouther Beltaief,1,2 Zied Mezgar,4 Mariem Khrouf,4 Ikram Chamtouri,5 Wahid Bouida,1,2 Hamdi Boubaker,1,2 Mohamed Amine Msolli,1,2 Zohra Dridi,6 Riadh Boukef,1,3 Semir Nouira1,2 1Research Laboratory LR12SP18, Monastir University, Monastir, 5019, Tunisia; 2Emergency Department, Fattouma Bourguiba University Hospital, Monastir, 5000, Tunisia; 3Emergency Department, Sahloul University Hospital, Sousse, 4011, Tunisia; 4Emergency Department, Farhat Hached University Hospital, Sousse, 4031, Tunisia; 5Department of Cardiology B, Fattouma Bourguiba University Hospital, Monastir, 5000, Tunisia; 6Department of Cardiology A, Fattouma Bourguiba University Hospital, Monastir, 5000, TunisiaCorrespondence: Semir Nouira, Emergency Department and Laboratory Research(LR12SP18), Fattouma Bourguiba University Hospital, Monastir, 5000, Tunisia, Tel +21673106046, Email [email protected]: Identifying heart failure (HF) in acute exacerbation of chronic obstructive pulmonary disease (AECOPD) can be challenging. Lung ultrasound sonography (LUS) B-lines quantification has recently gained a large place in the diagnosis of HF, but its diagnostic performance in AECOPD remains poorly studied.Purpose: This study aimed to assess the contribution of LUS B-lines score (LUS score) in the diagnosis of HF in AECOPD patients.Patients and methods: This is a prospective cross-sectional multicenter cohort study including patients admitted to the emergency department for AECOPD. All included patients underwent LUS. A lung ultrasound score (LUS score) based on B-lines calculation was assessed. A cardiac origin of dyspnea was retained for a LUS score greater than 15. HF diagnosis was based on clinical examination, pro-brain natriuretic peptide levels, and echocardiographic findings. The LUS score diagnostic performance was assessed by receiver operating characteristic (ROC) curve, sensitivity, specificity, and likelihood ratio at the best cutoffs.Results: We included 380 patients, mean age was 68± 11.6 years, sex ratio (M/F) 1.96. Patients were divided into two groups: the HF group [n=157 (41.4%)] and the non-HF group [n=223 (58.6%)]. Mean LUS score was higher in the HF group (26.8± 8.4 vs 15.3± 7.1; p< 0.001). The mean LUS score in the HF patients with reduced LVEF was 29.2± 8.7, and was 24.5± 7.6 in the HF patients with preserved LVEF. LUS score area under ROC curve for the diagnosis of HF was 0.71 [0.65– 0.76]. The best sensitivity (89% [85.9– 92,1]) was observed at the threshold of 5; the best specificity (85% [81.4– 88.6]) was observed at the threshold of 30. Correlation between LUS score and E/E’ ratio was good (R=0.46, p=0.0001).Conclusion: Our results suggest that LUS score could be helpful and should be considered in the diagnostic approach of HF in AECOPD patients, at least as a ruling in test.Keywords: chronic obstructive pulmonary disease, COPD, heart failure, dyspnea, lung ultrasound sonograph
Flow-aligned, single-shot fiber diffraction using a femtosecond X-ray free-electron laser
A major goal for X-ray free-electron laser (XFEL) based science is to elucidate structures of biological molecules without the need for crystals. Filament systems may provide some of the first single macromolecular structures elucidated by XFEL radiation, since they contain one-dimensional translational symmetry and thereby occupy the diffraction intensity region between the extremes of crystals and single molecules. Here, we demonstrate flow alignment of as few as 100 filaments (Escherichia coli pili, F-actin, and amyloid fibrils), which when intersected by femtosecond X-ray pulses result in diffraction patterns similar to those obtained from classical fiber diffraction studies. We also determine that F-actin can be flow-aligned to a disorientation of approximately 5 degrees. Using this XFEL-based technique, we determine that gelsolin amyloids are comprised of stacked β-strands running perpendicular to the filament axis, and that a range of order from fibrillar to crystalline is discernable for individual α-synuclein amyloids
Large-scale unit commitment under uncertainty: an updated literature survey
The Unit Commitment problem in energy management aims at finding the optimal production schedule of a set of generation units, while meeting various system-wide constraints. It has always been a large-scale, non-convex, difficult problem, especially in view of the fact that, due to operational requirements, it has to be solved in an unreasonably small time for its size. Recently, growing renewable energy shares have strongly increased the level of uncertainty in the system, making the (ideal) Unit Commitment model a large-scale, non-convex and uncertain (stochastic, robust, chance-constrained) program. We provide a survey of the literature on methods for the Uncertain Unit Commitment problem, in all its variants. We start with a review of the main contributions on solution methods for the deterministic versions of the problem, focussing on those based on mathematical programming techniques that are more relevant for the uncertain versions of the problem. We then present and categorize the approaches to the latter, while providing entry points to the relevant literature on optimization under uncertainty. This is an updated version of the paper "Large-scale Unit Commitment under uncertainty: a literature survey" that appeared in 4OR 13(2), 115--171 (2015); this version has over 170 more citations, most of which appeared in the last three years, proving how fast the literature on uncertain Unit Commitment evolves, and therefore the interest in this subject
On comparison principles for parabolic equations with nonlocal boundary conditions
A generalization of the comparison principle for a semilinear and a quasilinear parabolic equations with nonlocal boundary conditions including changing sign kernels is obtained. This generalization uses a positivity result obtained here for a parabolic problem with nonlocal boundary conditions
Some relaxation results for functionalsdepending on constrained strain and chemical composition
We prove some relaxation results in the spirit of Anza Hafsa and Mandallena for integral functionals arising in the study of coherent thermochemical equilibria for multiphase solids. The energy density exhibits all explicit dependence oil the deformation gradient and oil a vector field representing the chemical composition. The deformation gradient satisfies a determinant type constraint and the chemical composition a constraint on the modulus
Heterogeneous against homogeneous spectral response of polar molecules adsorbed on a real surface
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Curved thin films made of second grade materials
We consider a curved thin film made of a second grade material. The behaviour of the film is described by a nonconvex bulk energy depending on the first and second order derivatives of the deformation. When the thickness of the curved film goes to zero, we show, using -convergence arguments that the quasiminizers of three-dimensional energy converge to the minimizers of an energy whose grade two energy density has been -quasiconvexified, depending on a two dimensional deformation and a Cosserat vector
Dimensional reduction for energies with linear growth involving the bending moment
Abstract
A Γ -convergence analysis is used to perform a 3D–2D dimension reduction of variational problems with linear growth. The
adopted scaling gives rise to a nonlinear membrane model which, because of the presence of higher order external loadings inducing
a bending moment, may depend on the average in the transverse direction of a Cosserat vector field, as well as on the deformation
of the mid-plane. The assumption of linear growth on the energy leads to an asymptotic analysis in the spaces of measures and of
functions with bounded variation