Electrochemical Reactivation of AISI 409 Ferritic Stainless Steel Sheet Welded by Laser Process with application in aeronautical

The susceptibility to sensitization in 409 ferritic stainless steel (FSS) weldments was studied, by means of double loop electrochemical potentiokinetic reactivation test (DL-EPR). After the electrochemical test, the microstructure was analyzed by scanning electron microscopy (SEM) and the presence of elements with dispersive energy of X-rays (EDS), with the X-ray diffraction (XRD) technique they were identified present phases in different welds. Microhardness profiles were employed to evaluate the mechanical properties. With the aim of analyze the effect on the degree of sensitization to welding processes and the base material, a methodological analysis of gas metal arc welding GMAW, gas tungsten arc welding GTAW and LASER welding process was performed. The LASER process generated the highest ratio between the reactivation (Ir) and activation (Ia) current, despite it caused less microstructural change. The higher ratio Ir/Ia is attributed to the lack of penetration in the butt join, showing crevice corrosion. Keywords: 409 Ferritic stainless steel, DL-EPR, GMAW, GTAW, LASER

Rapid Prototyping for Evaluating Vehicular Communications

[Abstract] This Thesis details the different elements of a rapid prototyping system able to implement and evaluate vehicular communications fast, according to the continuously evolving requirements of the industry. The system is basically composed of a testbed and a channel emulator, which allow evaluating communication transceivers in realistic vehicular scenarios. Two different testbeds are introduced: a generic 2x2 system and a vehicular platform. The former is used to compare and study space-time block coding (STBC) transmissions at 2.4 GHz over different indoor channels. The latter makes use of software transceivers whose performance is evaluated when they work under artificial high-speed Rayleigh-fading scenarios. To show the capabilities of both platforms, three software transceivers have been developed following the specifications for the physical layers of the standards IEEE 802.11p, IEEE 802.11a and IEEE 802.16e (Mobile WiMAX). The present work details the different elements that make up each transceiver and indicates how to connect them to the rest of the system to perform evaluation measurements. Finally, single-antenna and multi-antenna performances are measured thanks to the design and implementation of three FPGA-based channel emulators that are able to recreate up to seven different vehicular scenarios that include urban canyons, suburban areas and highways[Resumo] A presente Tese detalla os elementos necesarios para constituir un sistema basado en prototipado rápido capaz de levar a cabo e avaliar comunicacións vehiculares. O hardware do sistema está composto básicamente por unha plataforma de probas (testbed) e un emulador de canal, os cales permiten avaliar o rendemento de transceptores inartiamicos recreando diferentes escenarios vehiculares. Inicialmente, este traballo céntrase na descripción do hardware do sistema, detallando a construcción e proba dunha plataforma multi-antena e un testebed vehicular. Estos sistemas permitiron, respectivamente, estudar o comportamento de códigos STBC (space-time block codes) en interiores e medir o rendemento de tranceptores software ao traballar a distintas velocidades vehiculares en canais con desvaecemento Rayleigh. Tres transceptores software foron creados seguindo as especificacións das capas físicas dos estándares IEEE 802.11p, IEEE 802.11a e IEEE 802.16e (Mobile WiMAX). Este traballo detalla os diferentes componentes de cada transceptor, indicando cómo conectalos ao resto do sistema para realizar a avaliacition do seu rendemento. Dita avaliación realizouse coa axuda de tres emuladores de canal basados en tecnoloxía FPGA (Field Programmable Gate Array), os cales son capaces de recrear ata sete escenarios vehiculares distintos, incluindo cañóns urbanos, zonas suburbanas e autopistas.[Resumen] La presente Tesis detalla los elementos necesarios para constituir un sistema basado en prototipado rtiapido capaz de llevar a cabo y evaluar comunicaciones vehiculares. El hardware del sistema está compuesto por una plataforma de pruebas (testbed) y un emulador de canal, los cuales permiten evaluar el rendimiento de transceptores inaltiambricos recreando diferentes escenarios vehiculares. Inicialmente, este trabajo se centra en la descripcition del hardware del sistema, detallando la construccition y prueba de una plataforma multi-antena y un testebed vehicular. Estos sistemas han permitido, respectivamente, estudiar el comportamiento de ctiodigos STBC (space-time block codes) en interiores y medir el rendimiento en canal con desvanecimiento Rayleigh de tranceptores software a distintas velocidades vehiculares. Tres transceptores software han sido creados siguiendo las especificaciones de las capas físicas de los estandares IEEE 802.11p, IEEE 802.11a e IEEE 802.16e (Mobile WiMAX). Este trabajo detalla los diferentes componentes de cada transceptor, indicando ctiomo conectarlos al resto del sistema para realizar la evaluacition de su rendimiento. Dicha evaluacition se realiztio con la ayuda de tres emuladores de canal basados en FPGAs (Field Programmable Gate Array), los cuales son capaces de recrear comunicaciones multi-antena en hasta siete escenarios vehiculares distintos, incluyendo cañones urbanos, zonas suburbanas y autopistas

Monkeypox, an unattended emerging infection.

El virus de la viruela símica estrechamente relacionado al virus de la viruela humana, es una zoonosis endémica de África occidental y central. En los seres humanos, la infección puede provocar una enfermedad similar a la viruela humana, aunque de menor severidad, pese a ello se asocia a una letalidad reportada variable desde menos del 1% al 11%. La transmisión se produce principalmente a través de gotitas respiratorias o contacto directo con el exudado de lesiones. La transmisión persona a persona está bien descrita, tanto comunitaria como nosocomial.  El cuadro clínico se caracteriza por un pródromo de fiebre, al cual se agrega exantema y linfadenopatía.  Dentro de las complicaciones se pueden incluir neumonía, encefalitis y queratitis. No existe un tratamiento aprobado establecido, aunque se incluyen estrategias en base a antivirales y vacunas.Monkeypox virus, closely related to human smallpox virus, is a zoonosis endemic to West and Central Africa. In humans, the infection can cause a disease similar to smallpox, although less severe, despite this it is associated with a variable reported lethality from less than 1% to 11%. Transmission occurs primarily through respiratory droplets or direct contact with exudate from lesions. Person-to-person transmission is well described, both in the community and nosocomial. The clinical picture is characterized by a prodrome of fever, to which is added rash and lymphadenopathy. Complications may include pneumonia, encephalitis, and keratitis. There is no established approved treatment, although strategies based on antivirals and vaccines are included

Identification of non-canonical Wnt receptors required for Wnt-3a-induced early differentiation of human neural stem cells

Wnt proteins preferentially activate either β-catenin-dependent or β-cateninindependent signals, but the activity of a particular Wnt also depends on cellular context and receptor availability. We previously reported that Wnt-3a induces neural differentiation of human embryonic stem cell-derived neural stem cells (NSCs) in a β-catenin-independent manner by activating a signal involving JNK and the AP-1 family member ATF-2. Here, we report the results of a gene silencing approach to identify the Wnt receptors that mediate this response to Wnt-3a. Silencing of ROR2 increased neuronal differentiation, as measured by expression of the genes DCX, NEUROD1 and NGN1, suggesting ROR2 signals normally prevent differentiation. Silencing of the other Wnt receptors singly did not affect Wnt-3ainduced neuronal differentiation. However, pair-wise silencing of ROR1 and FZD4 or FZD5 and of LRP6 and FZD4 or FZD5 inhibited neuronal differentiation, as detected by reductions in the expression of neuronal genes and immunocytochemical detection of DCX and NEUROD1 and DCX. Ectopic expression of these receptors in HEK 293 cells increased ATF2-dependent transcription. In addition, ROR1 co-immunoprecipitated with FZD4 and LRP6 in transfected HEK 293 cells and colocalized with FZD4 and with LRP6 at the cell surface of transfected L cells. Wnt-3a did not appear to affect these interactions but did alter the interactions between LRP6 and FZD4/5. Together, these observations highlight roles for ROR1, LRP6, FZD4 and FZD5 in neural stem cell differentiation and provide support for a model in which dynamic interactions among these receptors mediate Wnt-3a activation of ATF2 signaling

Preparation and characterization of biodegradable gelatine and starch films embedding cerium oxide nanoparticles stabilized by PLGA micelles for antibiofilm applications

Cerium oxide nanoparticles (CeO2NPs) have been widely investigated for numerous applications due to their redox activity, free radical scavenging property, and biofilm inhibition. Here we describe a new antibiofilm system based on CeO2NPs protected and stabilised by PLGA micelles embedded in two different biodegradable and biocompatible films. CeO2NPs were synthesised following the W/O microemulsion method and subsequently encapsulated in PLGA micelles according to the single emulsion/solvent procedure. All formulations (free NPs, empty micelles and loaded micelles) were incorporated in gelatine and starch films aimed at food packaging use. The chemical and physical characterizations of the NPs and micelles solutions were carried out by Dynamic Light Scattering (DLS), Transmission Electron Microscopy (TEM) and X-ray Photoelectron Spectroscopy (XPS). Blank films and films incorporating micelles and NPs were also characterized by Scanning Electron Microscopy (SEM) and by XPS. Antibacterial experiments were also performed to investigate the system viability for the final use