Gas interchange between bubble and emulsion phases in a 2D fluidized bed as revealed by two-fluid model simulations

Using two-fluid model simulations, the present work aims at characterizing the interchange due to gas advection between the emulsion phase and bubbles in fully bubbling beds of Geldart group B particles that are fluidized with air. In the studied beds the bubbles are slow, which means that the advection transport of gas through the bubble boundary is the main mechanism of gas interchange. In an initial verification step, the pressure distribution and the gas interchange coefficient for isolated bubbles obtained in the two-fluid simulation are compared with the classical potential flow theory of fluidized beds, providing concordant results. In a second step, the work analyzes the gas interchange in fully bubbling beds and the effects of the superficial velocity, bed height, and particle diameter on the interchange coefficient and the crossflow ratio. The results indicate that both the interchange coefficient and the crossflow ratio in bubbling beds are about two times those predicted by the potential theory of isolated bubbles. A corrected model for the gas interchange is proposed based on the introduction of the gas throughflow into the classical potential flow theory. As a consequence, the gas interchange coefficient in the corrected model is a function of the superficial gas velocity instead of the minimum fluidization velocity.This work has been partially funded by the Spanish Government (Project DPI2009-10518) and the Autonomous Community of Madrid (Project S2009/ENE-1660).Publicad

Global variability in gene expression and alternative splicing is modulated by mitochondrial content

Noise in gene expression is a main determinant of phenotypic variability. Increasing experimental evidence suggests that genome-wide cellular constraints largely contribute to the heterogeneity observed in gene products. It is still unclear, however, which global factors affect gene expression noise and to what extent. Since eukaryotic gene expression is an energy demanding process, differences in the energy budget of each cell could determine gene expression differences. Here, we quantify the contribution of mitochondrial variability (a natural source of ATP variation) to global variability in gene expression. We find that changes in mitochondrial content can account for ∼50% of the variability observed in protein levels. This is the combined result of the effect of mitochondria dosage on transcription and translation apparatus content and activities. Moreover, we find that mitochondrial levels have a large impact on alternative splicing, thus modulating both the abundance and type of mRNAs. A simple mathematical model in which mitochondrial content simultaneously affects transcription rate and splicing site choice can explain the alternative splicing data. The results of this study show that mitochondrial content (and/or probably function) influences mRNA abundance, translation, and alternative splicing, which ultimately affects cellular phenotypeThe authors would like to thank the Ministerio de Economia y Competitividad (Spain) (Grant numbers BFU2009-10792 and BFU2013-45918-R) and The Medical Research Council (U.K.) for supporting this work. We thank the Fundação Ciência e Tecnologia (Portugal) for funding R.P.N. A.R. held a postgraduate fellowship (FPU) from the Ministerio de Educación y Ciencia. The CBMSO receives an institutional grant from Fundación Ramón Arece

Rotura del ligamento deltoideo del tobillo: evaluación clínico-quirúrgica

No existe un criterio uniforme sobre la conduct a a seguir en el tratamient o de la rotur a del ligamento deltoideo del tobillo. Se ha n revisado 36 paciente s diagnosticados y tra - tado s quirúrgicament e de rotur a de dicho ligamento, la mayorí a de la s veces est a lesión iba acompañad a de fractur a del maleolo peroneo. Se ha valorado la etiología, el mecanismo lesional y los resultados siguiendo la clasificación de Cedell, considerándos e estos últimos como buenos en la práctic a totalidad de los casos. En cuatro de los paciente s (11%), se presentó como únic a secuela la limitación de la movilidad en los últimos grados de flexo-extensiónUniform criteria about the actions to be taken in the tearing of the ankle deltoid ligament d o no t exist. Thirt y si x patients diagnose d an d surgicall y treate d becaus e o f th e tearin g o f th e abov e mentione d ligamen t hav e bee n reviewed . Most o f th e times, this lesio n wa s accompanie d b y a fractur e o f th e peronea l maleolus. Etiology , injur y mechanism s an d results followin g Cedell's clasificatio n hav e bee n evaluate d an d th e results hav e bee n considere d goo d i n practicall y all cases. I n fou r patients, th e onl y secuel a wa s a limitatio n o f th e most extrem e grade s o f flexo-extension

Estudio de calidad de vida de pacientes con coxartrosis

La artroplastia de cadera secundaria a artrosis es una de las intervenciones más frecuentes dentro de la cirugía ortopédica. La coxartrosis produce una limitación funcional severa, que invalida a los pacientes y los hace dependientes para sus actividades cotidianas. Se calcula la calidad de vida aportada en las intervenciones de reemplazo articular de cadera de 85 pacientes con coxartrosis utilizando el “EQ-5D”. La puntuación media preoperatoria fue 0,222 ± 0,320 y la postoperatoria 0,794 ± 0,251. El incremento de calidad de vida en función de la edad de los pacientes siguió una tendencia descendente (β= −0,010), sin diferencias significativas (p=0,214). El incremento de calidad de vida no se vió condicionado por la presencia de infección (p>0,5), duración de la intervención (p>0,5) ni tiempo de estancia hospitalaria (p>0,5). La sustitución de esta articulación ha transformado la vida de muchos de los pacientes incrementando su calidad de vida, principalmente en pacientes que ingresan por coxartrosis en comparación con otros diagnósticos.Hip replacement secondary to osteoarthritis is one of the most performed surgeries in orthopaedic surgery. Osteoarthritis produces a severe functional limitation that invalidates patients and makes them dependent for their daily activities. It is calculated the quality of life provided by hip replacement procedure in 85 osteoarthritis patients using the “EQ-5D”. The mean preoperative score was 0.222 ± 0.320 and the postoperative score 0.794 ± 0.251. The increase in quality of life according to patients age followed a descendent tendency (β= −0.010), without a statitically relationship (p=0.214). The increase in quality of life was not conditioned by infection (p>0.5), length of stay (p>0.5) or length of the procedure (p>0.5). Joint replacement has changed the lives of many patients, increasing their quality of life, mainly in osteoarthritis patients compared to patients with other diagnosis

Advanced determination of piezoelectric properties of AlN thin films on silicon substrates

Piezoelectric deformations of thin, aluminum nitride (AlN) layers, on top of a silicon substrate, were studied by numerical calculations and interferometric measurements. Our calculation by finite element method demonstrates that substrate deformation under the top electrode may be comparable to the electric field induced deformation in the thin AlN layer, for a given applied voltage. Simulations also show the effect of a clamped or free substrate condition and the relative contributions of d33 and d31 piezoelectric constants. A Laser scanning vibrometry technique was used to measure deformations in the top surface with sub-picometer vertical resolution. By comparing calculations and experimental data, quantitative information about both d33 and d31 constants can be obtained

Piezoelectric characterization of ain thin films on silicon substrates

The electric field induced deformations of thin piezoelectric, aluminium nitride (AlN) layers, on top ofa silicon substrate, were studied by numerical calculations and interferometric measurements. Our calculationby finite element method demonstrates that substrate deformation under the top electrode may be comparableto the deformation in the thin AlN layer, for a given applied voltage. Simulations also show the effect of aclamped or free substrate condition and the relative contributions of d33 and d31 piezoelectric constants. ALaser scanning vibrometry technique was used to measure deformations in the top surface with sub-picometervertical resolution. By comparing calculations and experimental data, quantitative information about both d31and d33 constants can be obtained

Simulation and laser vibrometry characterization of piezoelectric AlN thin films

In this paper, the electric field induced deformations of sputter-deposited piezoelectric aluminum nitride thin films sandwiched between electrodes on top of a silicon substrate are studied by numerical calculations and scanning laser interferometric measurements. In our calculations based on the finite element method, the results show the displacement of the top and bottom surfaces of both the thin film and the substrate, for either a free or a perfectly clamped structure. The confirmation that the bottom surface of the film is deformed reveals the limitations of techniques that only access the top surface, as well as the double-beam interferometric configuration, under specific conditions. In addition, the simulations demonstrate the dependence of the displacements on the size of the upper electrode and the contribution of the transverse piezoelectric coefficient d31 to the features of the displacement profiles. A laser scanning vibrometry technique was used to measure deformations on the top surface with subpicometer vertical resolution. By comparing the calculated and the experimental displacement profiles, an advanced approach is discussed to obtain accurate quantitative information of both coefficients d31 and d33

Aluminium Nitride Solidly Mounted BAW Resonators with Iridium Electrodes

In this work we investigated the performance of aluminium nitride (AlN)-based solidly mounted resonators (SMR) made with iridium (Ir) bottom electrodes. Ir/AlN/metal stacks were grown on top of insulating Bragg mirrors composed of alternate λ/4 layers of silicon oxi-carbide (SiOC) and silicon nitride (Si3N4).Ir electrodes of various thicknesses were electron-beam evaporated on different adhesion layers, which also acted as seed layers. AlN was deposited by sputtering after conditioning the Ir electrode by a soft-etch with Ar+ ions, which was essential to achieve high quality AlN films. The structure and morphology of the different layers were analysed by x-ray diffraction (XRD) and atomic force microscopy (AFM). The frequency response of the SMRs was assessed by measuring the input scattering parameterS11 with a network analyzer. The experimental results were fitted to the Butterworth-Van Dyke circuital model. The effective electromechanical coupling factor k2eff, and the quality factor Q of the resonators were derived from the experimental data. The influence of the thickness, crystal quality and roughness of the Ir bottom electrodes on the performance of the resonators was investigated

BAW Resonators Based on AlN with Ir Electrodes for Digital Wireless Transmissions

We investigate the performance of aluminum nitride (AlN)-based solidly mounted resonators (SMR) made with iridium (Ir) electrodes for applications in WCDMA filters. Ir/AlN/Ir stacks are grown on top of insulating Bragg mirrors composed of alternate λ/4 layers of silicon oxycarbide (SiOC) and silicon nitride (Si3N4). We have developed the technological processes for the fabrication of filters including the trimming of the Ir top electrode for the tuning of the bandwidth. The influence of the thickness of the top electrode after the tuning process in the performance of the SMRs and filters is analyzed. The performance of the devices is compared with that of SMRs and filters of identical design made with Mo electrodes