3,494 research outputs found
Ultra-Broadband Directional Couplers Using Microstrip with Dielectric Overlay in Millimeter-Wave Band
Nowadays, millimeter-wave systems are being a key factor to develop wide band applications. In this paper, a directional coupler in millimeter-wave band using dielectric overlay is presented. This leads us to technology aspects, in directional coupler design, are key points to achieve the proper response of the circuit. The coupler proposed in this paper covers the 15-45 GHz band and its response has 15-dB coupling-level, 1-dB coupling-ripple and a reflection coefficient better than 10 dB
Comparative Analysis of Tolerances Allocation in Mechanical Assemblies based on Cost-tolerance Curves
El presente trabajo propone un método para la determinación de los valores de las tolerancias individuales de las piezas que forman un conjunto ensamblado a partir de valores de tolerancias especificados en el conjunto final, optimizando el coste total de fabricación de las piezas individuales a partir de funciones de coste-tolerancia basadas en el proceso de fabricación de cada una de ellas. Para ello se parte de los principales trabajos desarrollados en la línea de asignación de tolerancias y se realiza la propuesta del modelo de trabajo, basado en la optimización de costes a partir de la aplicación del método de los multiplicadores de Lagrange a diversas curvas de coste-toleranci
Desarrollo de Competencias. Caso Práctico: Estudiantes Voluntarios en Congreso Científico
El desarrollo de competencias transversales en un entorno de trabajo potencia las capacidades de integración de los estudiantes en el mundo laboral.
El presente trabajo describe la experiencia de colaboración de estudiantes voluntarios en el pasado Congreso Ibérico de Agroingeniería y Ciencias Hortícolas celebrado en Madrid en el año 2013. El equipo de 15 voluntarios, compuesto por estudiantes procedentes de estudios de grado, ingenierías, máster y doctorado, desarrolló múltiples funciones de apoyo a la organización. Las funciones realizadas por los voluntarios supusieron una experiencia de aprendizaje activo en la que éstos pudieron desarrollar competencias relevantes para su futura vida laboral.
Se proponen diversas competencias extraídas de las especificadas por la ETSI Agrónomos de la UPM para la
evaluación de prácticas en empresa de sus estudiantes; en el RD 1393/2007, que establece la ordenación de las
enseñanzas universitarias oficiales; en el Marco Español de Cualificaciones para la Educación Superior (MECES) y el Marco Europeo (EQF); y las establecidas por organizaciones como las sociedades europea y Americana para la formación de ingenieros (SEFI y ABET), relacionando las funciones llevadas a cabo por los voluntarios con las competencias desarrolladas. Finalmente se evalúa el desarrollo de estas competencias mediante la información recabada dentro del plan de calidad del congreso y que comprende la autoevaluación de los voluntarios junto con diversas en
cuestas de valoración de resultados y satisfacción completadas, tanto por parte de los asistentes como de los moderadores de sesiones durante el congreso
Multiwavelength study of the star formation in the bar of NGC 2903
NGC 2903 is a nearby barred spiral with an active starburst in the center and
Hii regions distributed along its bar. We aim to analyse the star formation
properties in the bar region of NGC 2903 and study the links with the typical
bar morphological features. A combination of space and ground-based data from
the far-ultraviolet to the sub-millimeter spectral ranges is used to create a
panchromatic view of the NGC 2903 bar. We produce two catalogues: one for the
current star formation regions, as traced by the halpha compact emission, and a
second one for the ultraviolet (UV) emitting knots, containing positions and
luminosities. From them we have obtained ultraviolet colours, star formation
rates, dust attenuation and halpha EWs, and their spatial distribution have
been analysed. Stellar cluster ages have been estimated using stellar
population synthesis models (Starburst99). NGC 2903 is a complex galaxy, with a
very different morphology on each spectral band. The CO(J=1-0) and the 3.6
micron emission trace each other in a clear barred structure, while the halpha
leads both components and it has an s-shape distribution. The UV emission is
patchy and does not resemble a bar. The UV emission is also characterised by a
number of regions located symmetrically with respect to the galaxy center,
almost perpendicular to the bar, in a spiral shape covering the inner ~2.5 kpc.
These regions do not show a significant halpha nor 24 micron emission. We have
estimated ages for these regions ranging from 150 to 320 Myr, being older than
the rest of the UV knots, which have ages lower than 10 Myr. The SFR calculated
from the UV emission is ~0.4 M/yr, compatible with the SFR as derived
from halpha calibrations (M/yr).Comment: Accepted for publication in A&
Detection of a putative TetR-like gene related to Mycobacterium bovis BCG growth in cholesterol using a gfp-transposon mutagenesis system
In vitro transposition is a powerful genetic tool for identifying mycobacterial virulence genes and studying virulence factors in relation to the host. Transposon shuttle mutagenesis is a method for constructing stable insertions in the genome of different microorganisms including mycobacteria. Using an IS1096 derivative, we have constructed the Tngfp, a transposon containing a promoterless green fluorescent protein (gfp) gene. This transposon was able to transpose randomly in Mycobacterium bovis BCG. Bacteria with a single copy of the gfp gene per chromosome from an M. bovis BCG::Tngfp library were analyzed and cells exhibiting high levels of fluorescence were detected by flow cytometry. Application of this approach allowed for the selection of a mutant, BCG_2177c::Tngfp (BCG-Tn), on the basis of high level of long-standing fluorescence at stationary phase. This BCG-Tn mutant showed some particular phenotypic features compared to the wild type strain, mainly during stationary phase, when cholesterol was used as a sole carbon source, thus supporting the relationships of the targeted gene with the regulation of cholesterol metabolism in this bacteria. This approach showed that Tngfp is a potentially useful tool for studying the involvement of the targeted loci in metabolic pathways of mycobacteria
Low prostaglandin E2 and cyclooxygenase expression in nasal mucosa fibroblasts of aspirin-intolerant asthmatics.
Background and objective: Anomalies in the regulation of cyclooxygenase (COX)-1 and-2 have been described in nasal polyps of aspirin-induced asthma (AIA). Whether these anomalies are specific to nasal polyps or affect all the nasal mucosa (NM) of upper airways is still unclear. The objective of this study was to compare the COX pathway in NM of AIA patients with the NM of control subjects. Methods: Fibroblasts were isolated from NM of 5 AIA patients (AIA-NM) and 5 control subjects (control-NM). Cells were treated with 10 ng/ml IL-1b for up to 72 hours. Prostaglandin E2 (PGE2) production was measured by ELISA, expression of COX-1 protein by Western blot, and COX-2 protein by ELISA, Western blot and immunofluorescence techniques. Results: IL-1b increased PGE2 production and COX-1 protein expression in control-NM fibroblasts, but no changes were found in AIA-NM. IL-1b provoked a significant timedependent increase in COX-2 protein expression in control-NM fibroblasts but had a very mild effect on COX-2 protein expression in AIA-NM. Conclusions: Our data suggest that abnormalities in the COX pathway are not a phenomenon exclusive to nasal polyp mucosa as they are also present in all the nasal mucosa of AIA patients. These anomalies may be involved in the pathogenesis of airway inflammation and NSAID intolerance in asthma patients with chronic rhinosinusitis and nasal polyposis
Lavandin essential oil combined with the biopolymer PHBV, poly(3-hydroxybutyrate-co-3-hydroxyvalerate), for wound treatment
In this work, poly(3-hydroxybutyrate-co-3-hydroxyvalerate), PHBV, was combined with lavandin essential oil (LavEO), from Lavandula hybrida grown in Argentina. Linalool (36%), linalyl acetate (29%) 1,8-cineole (6%) and camphor (6%) were its main compounds as analyzed by GC-MS. PHBV is a biodegradable copolyester from a bacterial source; PHBV porous scaffolds have been shown to be suitable for fibroblast and keratinocyte proliferation [1,2] and thus for skin regeneration. In addition, LavEO exhibits strong anti-inflammatory and antibacterial activity, what improves wound healing [4,5]. Purified monoterpenes and entire EOs have been combined with other biopolymers for different applications but scarcely for wound healing and never previously with PHBV [6]. PHBV porous membranes, 100-200 µm thickness, containing LavEO at 2, 4 or 8% m/m were obtained by an emulsion-solvent evaporation method. LavEO-PHBV membranes did not show cytotoxicity when tested on NIH/3T3 fibroblasts (according to the ISO 10993-5 standard). SEM membrane analysis showed, in all cases, a high level of porosity, ̴ 20% of the surface. Keratinocytes (KC) adhesion and proliferation were evaluated with the HaCaT cell line. Membranes containing 2 or 4% of LavEO, allowed KC proliferation of the same level as that of PHBV membrane controls. However, cells neither adhered to nor proliferated on membranes with 8% LavEO although their hydrophobicity, estimated by the contact angle, was similar to that of 4%-LavEO membranes. The reduction in the elastic modulus–determined by the dynamic mechanical analysis–due to the presence of LavEO, suggests its plasticizer effect (control E=305±10 MPa; 8%-LavEO membrane E=150±20 MPa). According to these results, 2 or 4% LavEO-PHBV membranes seem as a promising treatment, especially in the case of infected and chronic wounds, often arrested at the inflammatory phase
The effects of high-intensity interval training on glucose metabolism, cardiorespiratory fitness and weight control in subjects with diabetes: systematic review a meta-analysis
Aim: The objective of this meta-analysis was to explore the effects of high-intensity interval training (HIIT) compared with control conditions (CON) or moderate intensity continuous training (MICT) on glycemic parameters in diabetes subjects. Methods: Pubmed, Embase and Google Scholar databases were searched for HIIT interventions that were carried out in diabetic subjects and exploring fasting glucose, glycated haemoglobin (HbA1c), fasting insulin and/or HOMA-IR. Results: This systematic review retrieved a total of 1741 studies of which 32 articles fulfilled the eligibility criteria. Nineteen trials were included in the meta-analysis since they compared HIIT intervention with CON or MICT group. There was a significantly reduction of fasting glucose of 13.3 mg/dL (p < 0.001), Hb1Ac -0.34% (p < 0.001), insulin -2.27 UI/L (p = 0.003), HOMA-IR -0.88 (p = 0.005) in the HIIT-group compared with CON-group. Nevertheless, this reduction was not significantly different when comparing HIIT with MICT (p = 0.140, p = 0.315, p = 0.520 and p = 0.389). Besides, there was a significant increase of absolute VO2max of 0.21 L/min (p < 0.001) and relative VO2max of 2.94 ml/kg/min (p < 0.001) in the HIIT-group compared with the CON-group and the MICT-group (0.22 L/min, p = 0.025) and (0.97 ml/kg/min, p = 0.045). Conclusions: These findings revealed that HIIT intervention led to significant improvement in glycemic control and insulin resistance in subjects with diabetes compared with CON-group
Amyloid- β reduces the expression of neuronal FAIM-L, thereby shifting the inflammatory response mediated by TNF α from neuronal protection to death
The brains of patients with Alzheimer's disease (AD) present elevated levels of tumor necrosis factor- α (TNF α), a cytokine that has a dual function in neuronal cells. On one hand, TNF α can activate neuronal apoptosis, and on the other hand, it can protect these cells against amyloid- β (A β) toxicity. Given the dual behavior of this molecule, there is some controversy regarding its contribution to the pathogenesis of AD. Here we examined the relevance of the long form of Fas apoptotic inhibitory molecule (FAIM) protein, FAIM-L, in regulating the dual function of TNF α. We detected that FAIM-L was reduced in the hippocampi of patients with AD. We also observed that the entorhinal and hippocampal cortex of a mouse model of AD (PS1xAPP) showed a reduction in this protein before the onset of neurodegeneration. Notably, cultured neurons treated with the cortical soluble fractions of these animals showed a decrease in endogenous FAIM-L, an effect that is mimicked by the treatment with A β -derived diffusible ligands (ADDLs). The reduction in the expression of FAIM-L is associated with the progression of the neurodegeneration by changing the inflammatory response mediated by TNF α in neurons. In this sense, we also demonstrate that the protection afforded by TNF α against A β toxicity ceases when endogenous FAIM-L is reduced by short hairpin RNA (shRNA) or by treatment with ADDLs. All together, these results support the notion that levels of FAIM-L contribute to determine the protective or deleterious effect of TNF α in neuronal cells
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