A space–time Trefftz discontinuous Galerkin method for the acoustic wave equation in first-order formulation

We introduce a space–time Trefftz discontinuous Galerkin method for the first-order transient acoustic wave equations in arbitrary space dimensions, extending the one-dimensional scheme of Kretzschmar et al. (IMA J Numer Anal 36:1599–1635, 2016). Test and trial discrete functions are space–time piecewise polynomial solutions of the wave equations. We prove well-posedness and a priori error bounds in both skeleton-based and mesh-independent norms. The space–time formulation corresponds to an implicit time-stepping scheme, if posed on meshes partitioned in time slabs, or to an explicit scheme, if posed on “tent-pitched” meshes. We describe two Trefftz polynomial discrete spaces, introduce bases for them and prove optimal, high-order h-convergence bounds

Integral potential method for a transmission problem with Lipschitz interface in R^3 for the Stokes and Darcy–Forchheimer–Brinkman PDE systems

The purpose of this paper is to obtain existence and uniqueness results in weighted Sobolev spaces for transmission problems for the non-linear Darcy-Forchheimer-Brinkman system and the linear Stokes system in two complementary Lipschitz domains in R3, one of them is a bounded Lipschitz domain with connected boundary, and the other one is the exterior Lipschitz domain R3 n. We exploit a layer potential method for the Stokes and Brinkman systems combined with a fixed point theorem in order to show the desired existence and uniqueness results, whenever the given data are suitably small in some weighted Sobolev spaces and boundary Sobolev spaces

Tau Structures

Tau is a microtubule-associated protein that plays an important role in axonal stabilization, neuronal development, and neuronal polarity. In this review, we focus on the primary, secondary, tertiary, and quaternary tau structures. We describe the structure of tau from its specific residues until its conformation in dimers, oligomers, and larger polymers in physiological and pathological situations

Pacientes españoles con síndrome de hipoventilación central incluidos en el Registro europeo. Datos del 2015

Introducción El síndrome de hipoventilación central congénita (SHCC) es una enfermedad genética muy rara causada por mutaciones en PHOX2B; en 2010 se creó el Consorcio Europeo del Síndrome de Hipoventilación Central, que en 2012 implantó un Registro online de pacientes para optimizar su cuidado. Objetivo Conocer las características y la evolución de los pacientes españoles con SHCC y detectar áreas de mejora. Materiales y método Se analizaron los datos actualizados en diciembre del 2015 de los pacientes españoles del Registro europeo. Resultados Se registró a 38 pacientes, nacidos entre 1987 y 2013, procedentes de 18 hospitales. El 34, 2% eran mayores de 18 años. Han fallecido 3 pacientes. Aportaban estudio del gen PHOX2B 37 (97, 3%), 32 (86, 5%) con mutación. Los genotipos 20/25, 20/26 y 20/27 representaron el 84, 3% de las mutaciones. Las disautonomías fueron más frecuentes y graves en portadores de genotipos con mayores expansiones de polialaninas. El 47% de pacientes asociaba alteraciones oculares, el 16% Hirschsprung, el 13% hipoglucemias y el 5% tumores. Treinta pacientes (79%) debutaron en el periodo neonatal y 8 (21%) posteriormente (inicio/diagnóstico tardío). Ocho niños (21%) recibieron inicialmente ventilación domiciliaria con mascarilla; 5 eran lactantes con comienzo neonatal, 2 de ellos precisaron cambio a traqueostomía tras presentar parada cardiorrespiratoria; ambos tenían mutaciones graves. Han sido decanulados y transferidos a mascarilla el 34, 3% de los pacientes (edad media: 13, 7 años). El 29, 4% de los niños escolarizados precisaron refuerzo educativo. Conclusión La implementación del Registro en España de pacientes con SHCC ha permitido identificar aspectos relevantes para optimizar sus cuidados, tales como la importancia del estudio genético para el diagnóstico y la estimación de gravedad, la frecuencia elevada de alteraciones oculares y de necesidad de refuerzo educativo, y algunas limitaciones de las técnicas ventilatorias. Introduction Congenital Central Hypoventilation Syndrome (CCHS) is a very rare genetic disease. In 2012 the European Central Hypoventilation Syndrome (EuCHS) Consortium created an online patient registry in order to improve care. Aim To determine the characteristics and outcomes of Spanish patients with CCHS, and detect clinical areas for improvement. Materials and method An assessment was made on the data from Spanish patients in the European Registry, updated on December 2015. Results The Registry contained 38 patients, born between 1987 and 2013, in 18 hospitals. Thirteen (34.2%) were older than 18 years. Three patients had died. Genetic analysis identified PHOX2B mutations in 32 (86.5%) out of 37 patients assessed. The 20/25, 20/26 and 20/27 polyalanine repeat mutations (PARMs) represented 84.3% of all mutations. Longer PARMs had more, as well as more severe, autonomic dysfunctions. Eye diseases were present in 47%, with 16% having Hirschsprung disease, 13% with hypoglycaemia, and 5% with tumours. Thirty patients (79%) required ventilation from the neonatal period onwards, and 8 (21%) later on in life (late onset/presentation). Eight children (21%) were using mask ventilation at the first home discharge. Five of them were infants with neonatal onset, two of them, both having a severe mutation, were switched to tracheostomy after cardiorespiratory arrest at home. Approximately one-third (34.3%) of patients were de-cannulated and switched to mask ventilation at a mean age of 13.7 years. Educational reinforcement was required in 29.4% of children attending school. Conclusion The implementation of the EuCHS Registry in Spain has identified some relevant issues for optimising healthcare, such as the importance of genetic study for diagnosis and assessment of severity, the high frequency of eye disease and educational reinforcement, as well as some limitations in ventilatory techniques

Recommended Approaches to Minimize Aerosol Dispersion of SARS-CoV-2 During Noninvasive Ventilatory Support Can Cause Ventilator Performance Deterioration: A Benchmark Comparative Study

Background: SARS-CoV-2 aerosolization during noninvasive positive-pressure ventilation may endanger health care professionals. Various circuit setups have been described to reduce virus aerosolization. However, these setups may alter ventilator performance. Research Question: What are the consequences of the various suggested circuit setups on ventilator efficacy during CPAP and noninvasive ventilation (NIV)? Study Design and Methods: Eight circuit setups were evaluated on a bench test model that consisted of a three-dimensional printed head and an artificial lung. Setups included a dual-limb circuit with an oronasal mask, a dual-limb circuit with a helmet interface, a single-limb circuit with a passive exhalation valve, three single-limb circuits with custom-made additional leaks, and two single-limb circuits with active exhalation valves. All setups were evaluated during NIV and CPAP. The following variables were recorded: the inspiratory flow preceding triggering of the ventilator, the inspiratory effort required to trigger the ventilator, the triggering delay, the maximal inspiratory pressure delivered by the ventilator, the tidal volume generated to the artificial lung, the total work of breathing, and the pressure-time product needed to trigger the ventilator. Results: With NIV, the type of circuit setup had a significant impact on inspiratory flow preceding triggering of the ventilator (P < .0001), the inspiratory effort required to trigger the ventilator (P < .0001), the triggering delay (P < .0001), the maximal inspiratory pressure (P < .0001), the tidal volume (P = .0008), the work of breathing (P < .0001), and the pressure-time product needed to trigger the ventilator (P < .0001). Similar differences and consequences were seen with CPAP as well as with the addition of bacterial filters. Best performance was achieved with a dual-limb circuit with an oronasal mask. Worst performance was achieved with a dual-limb circuit with a helmet interface. Interpretation: Ventilator performance is significantly impacted by the circuit setup. A dual-limb circuit with oronasal mask should be used preferentially