A second order in time modified Lagrange-Galerkin finite element method for the incompressible Navier-Stokes equations

We introduce a second order in time modified Lagrange--Galerkin (MLG) method for the time dependent incompressible Navier--Stokes equations. The main ingredient of the new method is the scheme proposed to calculate in a more efficient manner the Galerkin projection of the functions transported along the characteristic curves of the transport operator. We present error estimates for velocity and pressure in the framework of mixed finite elements when either the mini-element or the $P2/P1$ Taylor--Hood element are used

A subgrid viscosity Lagrance-Galerkin method for convection-diffusion problems

We present and analyze a subgrid viscosity Lagrange-Galerk in method that combines the subgrid eddy viscosity method proposed in W. Layton, A connection between subgrid scale eddy viscosity and mixed methods. Appl. Math. Comp., 133: 14 7-157, 2002, and a conventional Lagrange-Galerkin method in the framework of P1⊕ cubic bubble finite elements. This results in an efficient and easy to implement stabilized method for convection dominated convection diffusion reaction problems. Numerical experiments support the numerical analysis results and show that the new method is more accurate than the conventional Lagrange-Galerkin one

Operability and selectivity of beach seine in the artisanal fishing, Lambayeque Region

artesanal de la Región Lambayeque, se estudió en tres salidas de campo, en 12 zonas de pesca. En 19 lances de pesca, se capturó en total 12.606 kg de peces e invertebrados. El bagre (Galeichthys peruvianus) fue la especie dominante con una captura total de 10.546 kg (83,6%). La captura fue mayor en el copo (89,63%) que en las alas (9,82%) y sobrecopo (0,53%). El descarte de la captura total fue 250 kg de ejemplares juveniles. El uso de malla cuadrada en el copo evidenció alta selectividad sobre especies fusiformes y, baja selectividad sobre los de cuerpo lateralmente comprimido y alto, por lo que no se recomienda su uso en este arte de pesca

Eficacia y tolerabilidad del carbón activado más plata en el tratamiento local de heridas infectadas

Actualmente la terapia basada en el principio de proveer humedad en el ambiente de una herida se conoce como cuidado avanzado de heridas. Existe una gran cantidad de apósitos activos que se utilizan en hospitales y centros privados por ejemplo, los que contienen carbón activado más plata, hidrocoloides, alginatos, hidropolímeros, todos ellos promueven humedad y debridamiento autolítico. El propósito de este estudio fue valorar la eficacia y tolerabilidad del carbón activado más plata en heridas infectadas. Dieciséis pacientes (10 mujeres y 6 hombres) con úlceras de diversa etiología internados en el servicio médico de Dermatología del hospital Luis Vernaza, Guayaquil formaron parte de este estudio por un tiempo de 4 años. Se registró el tamaño de las heridas y se realizaron cultivos bacterianos de las úlceras, el registro fotográfico; se realizó al inicio y en cada recambio de apósito. De los dieciséis pacientes solo uno abandonó el estudio, una paciente epitelizó el 100%, en los restantes se observó aumento del tejido de granulación y disminución del exudado. El objetivo del estudio fué preparar las ulceras para tratamiento quirúrgico, salvo el caso que epitelizó el 100%,el cual deja una ventana abierta en pacientes seleccionados en donde se puede llegar al cierre definitivo. El tejido periulceral permaneció indemne durante todo el tratamiento. Este estudio propone que el tratamiento local de heridas infectadas con carbón activado más plata, es eficaz ya que permite un apropiado manejo de la infección bacteriana y un correcto ambiente húmedo

Free PCR virus detection via few-layer bismuthene and tetrahedral DNA nanostructured assemblies

In this work we describe a highly sensitive method based on a biocatalyzed electrochemiluminescence approach. The system combines, for the first time, the use of few-layer bismuthene (FLB) as a platform for the oriented immobilization of tetrahedral DNA nanostructures (TDNs) specifically designed and synthetized to detect a specific SARS-CoV-2 gene sequence. In one of its vertices, these TDNs contain a DNA capture probe of the open reading frame 1 ab (ORF1ab) of the virus, available for the biorecognition of the target DNA/RNA. At the other three vertices, there are thiol groups that enable the stable anchoring/binding to the FLB surface. This novel geometry/approach enables not only the binding of the TDNs to surfaces, but also the orientation of the capture probe in a direction normal to the bismuthine surface so that it is readily accessible for binding/recognition of the specific SARS-CoV-2 sequence. The analytical signal is based on the anodic electrochemiluminescence (ECL) intensity of luminol which, in turn, arises as a result of the reaction with H2O2, generated by the enzymatic reaction of glucose oxidation, catalyzed by the biocatalytic label avidin-glucose oxidase conjugate (Av-GOx), which acts as co-reactant in the electrochemiluminescent reaction. The method exhibits a limit of detection (LOD) of 4.31 aM and a wide linear range from 14.4 aM to 1.00 μM, and its applicability was confirmed by detecting SARS-CoV-2 in nasopharyngeal samples from COVID-19 patients without the need of any amplification processPID2020-116728RB-I00, PID2020-116661RB-I00, PID2020-119352RB-I00, PDC2021-120782-C2, PID2022-138908NB-C31, CTQ2015-71955-REDT, S2018/NMT-434

Paving the way to point of care (POC) devices for SARS-CoV-2 detection

In this work we present a powerful, affordable, and portable biosensor to develop Point of care (POC) SARS-CoV-2 virus detection. It is constructed from a fast, low cost, portable and electronically automatized potentiostat that controls the potential applied to a disposable screen-printed electrochemical platform and the current response. The potentiostat was designed to get the best signal-to-noise ratio, a very simple user interface offering the possibility to be used by any device (computer, mobile phone or tablet), to have a small and portable size, and a cheap manufacturing cost. Furthermore, the device includes as main components, a data acquisition board, a controller board and a hybridization chamber with a final size of 10 × 8 × 4 cm. The device has been tested by detecting specific SARS-CoV-2 virus sequences, reaching a detection limit of 22.1 fM. Results agree well with those obtained using a conventional potentiostat, which validate the device and pave the way to the development of POC biosensors. In this sense, the device has finally applied to directly detect the presence of the virus in nasopharyngeal samples of COVID-19 patients and results confirm its utility for the rapid detection infected samples avoiding any amplification process.This work has been financially supported by the Spanish Ministry of Economy and Competitiveness (PID2020-116728RB-I00, CTQ2015-71955-REDT (ELECTROBIONET)) and Community of Madrid (TRANSNANOAVANSENS, S2018/NMT-4349). Authors also acknowledge REACT EU NANOCOV-CM project. We acknowledge the service from the MiNa Laboratory at IMN, and funding from Community of Madrid (project S2018/NMT-4291 TEC2SPACE), MINECO (project CSIC13-4E-1794) and EU (FEDER, FSE)”. RdC gratefully thanks support from Fundación IMDEA, UAM and Banco Santander (fondo supera 2020, convocatoria CRUE–CSIC–SANTANDER, project with reference 10.01.03.02.41).Peer reviewe

CASCADE: Naked eye-detection of SARS-CoV-2 using Cas13a and gold nanoparticles

The COVID-19 pandemic has brought to light the need for fast and sensitive detection methods to prevent the spread of pathogens. The scientific community is making a great effort to design new molecular detection methods suitable for fast point-of-care applications. In this regard, a variety of approaches have been developed or optimized, including isothermal amplification of viral nucleic acids, CRISPR-mediated target recognition, and read-out systems based on nanomaterials. Herein, we present CASCADE (CRISPR/CAS-based Colorimetric nucleic Acid DEtection), a sensing system for fast and specific naked-eye detection of SARS-CoV-2 RNA. In this approach, viral RNA is recognized by the LwaCas13a CRISPR protein, which activates its collateral RNase activity. Upon target recognition, Cas13a cleaves ssRNA oligonucleotides conjugated to gold nanoparticles (AuNPs), thus inducing their colloidal aggregation, which can be easily visualized. After an exhaustive optimization of functionalized AuNPs, CASCADE can detect picomolar concentrations of SARS-CoV-2 RNA. This sensitivity is further increased to low femtomolar (3 fM) and even attomolar (40 aM) ranges when CASCADE is coupled to RPA or NASBA isothermal nucleic acid amplification, respectively. We finally demonstrate that CASCADE succeeds in detecting SARS-CoV-2 in clinical samples from nasopharyngeal swabs. In conclusion, CASCADE is a fast and versatile RNA biosensor that can be coupled to different isothermal nucleic acid amplification methods for naked-eye diagnosis of infectious diseases.This work was supported by the Spanish Ministry of Economy and Competitiveness (SAF2017-87305-R, PID2020-119352RB-I00), Instituto de Salud Carlos III (FONDO-COVID19:COV20/00144 and COV20/00122) and Madrid Regional Government (NANOCOV-CM and IND2017/IND7809). C.E-N, M. L-V and C.R-D thank Madrid Regional Government for the pre-doctoral Grants (PEJD-2017-PRE/BMD-3730, PEJD-2018-PRE/IND-9584 and PEJD-2017-PRE/IND-4438). P.M.R thanks the Ministry of Economy, Industry and competitiveness of Spain for the FPI fellowship (BES-2017.082521). IMDEA Nanociencia acknowledges support from the ‘Severo Ochoa’ Programme for Centres of Excellence in R&D (MINECO, Grant SEV-2016-0686, CEX2020-001039-S).Peer reviewe