553 research outputs found

    Air gap influence on the vibro-acoustic response of Solar Arrays during launch

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    One of the primary elements on the space missions is the electrical power subsystem, for which the critical component is the solar array. The behaviour of these elements during the ascent phase of the launch is critical for avoiding damages on the solar panels, which are the primary source of energy for the satellite in its final configuration. The vibro-acoustic response to the sound pressure depends on the solar array size, mass, stiffness and gap thickness. The stowed configuration of the solar array consists of a multiple system composed of structural elements and the air layers between panels. The effect of the air between panels on the behaviour of the system affects the frequency response of the system not only modifying the natural frequencies of the wings but also as interaction path between the wings of the array. The usual methods to analyze the vibro-acoustic response of structures are the FE and BE methods for the low frequency range and the SEA formulation for the high frequency range. The main issue in the latter method is, on one hand, selecting the appropriate subsystems, and, on the other, identifying the parameters of the energetic system: the internal and coupling loss factors. From the experimental point of view, the subsystems parameters can be identified by exciting each subsystem and measuring the energy of all the subsystems composing the Solar Array. Although theoretically possible, in practice it is difficult to apply loads on the air gaps. To analyse this situation, two different approaches can be studied depending on whether the air gaps between the panels are included explicitly in the problem or not. For a particular case of a solar array of three wings in stowed configuration both modelling philosophies are compared. This stowed configuration of a three wing solar arrays in stowed configuration has been tested in an acoustic chamber. The measured data on the solar wings allows, in general, determining the loss factors of the configuration. The paper presents a test description and measurements on the structure, in terms of the acceleration power spectral density. Finally, the performance of each modelling technique has been evaluated by comparison between simulations with experimental results on a spacecraft solar array and the influence on the apparent properties of the system in terms of the SEA loss factors has been analyse

    Early imaging and molecular changes with neoadjuvant bevacizumab in stage ii/iii breast cancer

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    This prospective, phase II study evaluated novel biomarkers as predictors of response to bevacizumab in patients with breast cancer (BC), using serial imaging methods and gene expression analysis. Patients with primary stage II/III BC received bevacizumab 15 mg/kg (cycle 1; C1), then four cycles of neoadjuvant docetaxel doxorubicin, and bevacizumab every 3 weeks (C2–C5). Tumour proliferation and hypoxic status were evaluated using18F-fluoro-3'-deoxy-3'-L-fluorothymidine (FLT)-and18F-fluoromisonidazole (FMISO)-positron emission tomography (PET) at baseline, and during C1 and C5. Pre-and post-bevacizumab vascular changes were evaluated using dynamic contrastenhanced magnetic resonance imaging (DCE-MRI). Molecular biomarkers were assessed using microarray analysis. A total of 70 patients were assessed for treatment efficacy. Significant decreases from baseline in tumour proliferation (FLT-PET), vascularity, and perfusion (DCE-MRI) were observed during C1 (p = 0.001), independent of tumour subtype. Bevacizumab treatment did not affect hypoxic tumour status (FMISO-PET). Significant changes in the expression of 28 genes were observed after C1. Changes in vascular endothelial growth factor receptor (VEGFR)-2p levels were observed in 65 patients, with a > 20% decrease in VEGFR-2p observed in 13/65. Serial imaging techniques. © 2021 by the authors. Licensee MDPI, Basel, Switzerland

    Inhibition of intermediate-conductance calcium-activated K channel (KCa3.1) and fibroblast mitogenesis by a-linolenic acid and alterations of channel expression in the lysosomal storage disorders, fabry disease, and niemann pick C

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    The calcium/calmodulin-gated KCa3.1 channel regulates normal and abnormal mitogenesis by controlling K+-efflux, cell volume, and membrane hyperpolarization-driven calcium-entry. Recent studies suggest modulation of KCa3.1 by omega-3 fatty acids as negative modulators and impaired KCa3.1 functions in the inherited lysosomal storage disorder (LSD), Fabry disease (FD). In the first part of present study, we characterize KCa3.1 in murine and human fibroblasts and test the impact of omega-3 fatty acids on fibroblast proliferation. In the second, we study whether KCa3.1 is altered in the LSDs, FD, and Niemann-Pick disease type C (NPC). Our patch-clamp and mRNA-expression studies on murine and human fibroblasts show functional expression of KCa3.1. KCa currents display the typical pharmacological fingerprint of KCa3.1: Ca2+-activation, potentiation by the positive-gating modulators, SKA-31 and SKA-121, and inhibition by TRAM-34, Senicapoc (ICA-17043), and the negative-gating modulator, 13b. Considering modulation by omega-3 fatty acids we found that a-linolenic acid (a-LA) and docosahexanenoic acid (DHA) inhibit KCa3.1 currents and strongly reduce fibroblast growth. The a-LA-rich linseed oil and ¿-LA-rich borage oil at 0.5% produce channel inhibition while a-LA/¿-LA-low oils has no anti-proliferative effect. Concerning KCa3.1 in LSD, mRNA expression studies, and patch-clamp on primary fibroblasts from FD and NPC patients reveal lower KCa3.1-gene expression and membrane expression than in control fibroblasts. In conclusion, the omega-3 fatty acid, a-LA, and a-LA/¿-LA-rich plant oils, inhibit fibroblast KCa3.1 channels and mitogenesis. Reduced fibroblast KCa3.1 functions are a feature and possible biomarker of cell dysfunction in FD and NPC and supports the concept that biased lipid metabolism is capable of negatively modulating KCa3.1 expression

    Clinical Characteristics and Long-term outcomes of patients undergoing combined heart-kidney transplantation: a single-center experience

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    [Abstract] Background. The purpose of the study was to describe clinical characteristics and long-term survival of patients undergoing combined heart-kidney transplant in a single center. Methods. We conducted a retrospective analysis of 22 consecutive patients who underwent combined heart-kidney transplant at our institution between 1995 and 2013. Long-term outcomes were analyzed by means of the Kaplan-Meier method. Results. Four patients underwent re-do transplant (2 cardiac re-transplants, 1 kidney re-transplant, and 1 combined heart-kidney re-transplant). Most frequent underlying cardiac conditions were coronary artery disease (54%), dilated cardiomyopathy (23%), and chronic rejection of a previous heart graft (18%). Known causes of chronic renal dysfunction were nephroangioesclerosis (23%), drug-related toxicity (14%), and Wegener granulomatosis (5%). Non-specified chronic renal dysfunction was present in 50% patients. In-hospital postoperative mortality rate was 5 of 22 (23%). Causes of early death were directly related to kidney transplant surgery in 4 of 5 (80%) patients. Among the remaining 17 patients who surmounted the postoperative period, long-term survival rates 1 year, 5 years, and 10 years after HKT were 88%, 82%, and 65%, respectively. Over a mean follow-up of 6.7 ± 6.4 years, cumulative incidences of cytomegalovirus infection, coronary allograft vasculopathy, malignancy, and acute cardiac graft rejection were 41%, 6%, 24%, and 41%, respectively. There was no episode of acute renal graft rejection. At the end of follow-up, all survivors (n = 11) were in functional New York Heart Association class I. Mean creatinine serum level was 1.68 mg/dL. Conclusions. In our experience, combined heart-kidney transplant is a feasible therapeutic option that yielded favorable long-term outcomes, with a low cumulative incidence of cardiac graft dysfunction. These results were obtained at the expense of a significant risk of early postoperative mortality, which was mainly related to complications of kidney transplant surgery

    Compilation of parameterized seismogenic sources in Iberia for the SHARE European-scale seismic source model.

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    Abstract: SHARE (Seismic Hazard Harmonization in Europe) is an EC-funded project (FP7) that aims to evaluate European seismic hazards using an integrated, standardized approach. In the context of SHARE, we are compiling a fully-parameterized active fault database for Iberia and the nearby offshore region. The principal goal of this initiative is for fault sources in the Iberian region to be represented in SHARE and incorporated into the source model that will be used to produce seismic hazard maps at the European scale. The SHARE project relies heavily on input from many regional experts throughout the Euro-Mediterranean region. At the SHARE regional meeting for Iberia, the 2010 Working Group on Iberian Seismogenic Sources (WGISS) was established; these researchers are contributing to this large effort by providing their data to the Iberian regional integrators in a standardized format. The development of the SHARE Iberian active fault database is occurring in parallel with IBERFAULT, another ongoing effort to compile a database of active faults in the Iberian region. The SHARE Iberian active fault database synthesizes a wide range of geological and geophysical observations on active seismogenic sources, and incorporates existing compilations (e.g., Cabral, 1995; Silva et al., 2008), original data contributed directly from researchers, data compiled from the literature, parameters estimated using empirical and analytical relationships, and, where necessary, parameters derived using expert judgment. The Iberian seismogenic source model derived for SHARE will be the first regional-scale source model for Iberia that includes fault data and follows an internationally standardized approach (Basili et al., 2008; 2009). This model can be used in both seismic hazard and risk analyses and will be appropriate for use in Iberian- and European-scale assessments

    Karyotype Characterization of Nine Periwinkle Species (Gastropoda, Littorinidae)

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    Periwinkles of the family Littorinidae (Children, 1834) are common members of seashore littoral communities worldwide. Although the family is composed of more than 200 species belonging to 18 genera, chromosome numbers have been described in only eleven of them. A molecular cytogenetic analysis of nine periwinkle species, the rough periwinkles Littorina arcana, L. saxatilis, and L. compressa, the flat periwinkles L. obtusata and L. fabalis, the common periwinkle L. littorea, the mangrove periwinkle Littoraria angulifera, the beaded periwinkle Cenchritis muricatus, and the small periwinkle Melarhaphe neritoides was performed. All species showed diploid chromosome numbers of 2n = 34, and karyotypes were mostly composed of metacentric and submetacentric chromosome pairs. None of the periwinkle species showed chromosomal differences between male and female specimens. The chromosomal mapping of major and minor rDNA and H3 histone gene clusters by fluorescent in situ hybridization demonstrated that the patterns of distribution of these DNA sequences were conserved among closely related species and differed among less related ones. All signals occupied separated loci on different chromosome pairs without any evidence of co-localization in any of the species

    Desarrollo de la técnica de FICTION como nueva herramienta para el diagnóstico precoz de cáncer de pulmón

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    El cáncer de pulmón es una de las causas de muerte más frecuentes en el mundo occidental. La supervivencia global de los pacientes no supera el 15% a los 5 años, debido principalmente a que la mayor parte de los casos se diagnostican en estadios avanzados. Además de la prevención primaria, mediante la reducción del consumo de tabaco, son necesarias nuevas tecnologías para el diagnóstico precoz de la enfermedad. Estudios recientes han demostrado que el TAC helicoidal del tórax es efectivo en la detección de nódulos pulmonares malignos en estadios precoces. En la actualidad se está valorando su eficacia en series amplias de pacientes de alto riesgo. Recientemente se ha desarrollado una nueva técnica de citogenética molecular, el FICTION (Fluorescence Immunophenotyping and Interphase Cytogenetics as a Tool for the Investigation of Neoplasms). Esta técnica permite el análisis simultáneo de marcadores inmunofenotípicos y alteraciones genéticas presentes en las células tumorales. El objetivo de nuestro proyecto es su puesta a punto para el estudio de muestras de esputo y lavado broncoalveolar de pacientes con cáncer de pulmón. El fin último es estudiar la posibilidad de que esta técnica pueda ser utilizada, junto con el TAC helicoidal, en programas de detección precoz de cáncer de pulmón, para pacientes de alto riesgo. En este trabajo presentamos una revisión de la contribución de las distintas técnicas de citogenética al estudio del cáncer de pulmón y la metodología de trabajo que vamos a llevar a cabo en nuestro proyecto

    La Base de Datos de Fallas Activas en el Cuaternario de Iberia (QAFI v.2.0)

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    ABSTRACT. The Quaternary Active Faults Database of Iberia (QAFI) is an initiative lead by the Institute of Geology and Mines of Spain (IGME) for building a public repository of scientific data regarding faults having documented activity during the last 2.59 Ma (Quaternary). QAFI also addresses a need to transfer geologic knowledge to practitioners of seismic hazard and risk in Iberia by identifying and characterizing seismogenic fault-sources. QAFI is populated by the information freely provided by more than 40 Earth science researchers, storing to date a total of 262 records. In this article we describe the development and evolution of the database, as well as its internal architecture. Additionally, a first global analysis of the data is provided with a special focus on length and slip-rate fault parameters. Finally, the database completeness and the internal consistency of the data are discussed. Even though QAFI v.2.0 is the most current resource for calculating fault-related seismic hazard in Iberia, the database is still incomplete and requires further review.RESUMEN. La Base de Datos de Fallas Activas de Iberia (QAFI) es una iniciativa promovida por el Instituto Geológico y Minero de España (IGME) para construir un repositorio público de información científica sobre fallas con actividad en los últimos 2,59 Ma (Cuaternario). Además, la QAFI persigue establecer una base sobre la que facilitar la transferencia de conocimiento geológico al ámbito tecnológico de la gestión del riesgo sísmico en Iberia, en particular en la identificación y caracterización de fuentes sismogénicas tipo falla. La QAFI se ha construido a partir de la información proporcionada de modo altruista por más de 40 investigadores en ciencias de la Tierra conteniendo actualmente un total de de 262 registros. En este artículo se describe la concepción y evolución de la base de datos, y su arquitectura interna. Además, se ofrece un primer análisis global de los datos que contiene, con especial interés en parámetros tan importantes como la longitud y tasa de deslizamiento de las fallas. Finalmente se discuten dos temas cruciales en cualquier base de datos: su completitud y la homogeneidad de los datos. Se concluye que QAFI v.2.0, pese a ser la fuente más actualizada de información disponible en Iberia sobre peligrosidad sísmica de fallas concretas, dista aun de ser completa, por lo que nuevas revisiones y versiones deberán seguir llevándose a cabo en el futuro

    Grafting Snake Melon [Cucumis melo L. subsp. melo Var. flexuosus (L.) Naudin] in Organic Farming: Effects on Agronomic Performance; Resistance to Pathogens; Sugar, Acid, and VOC Profiles; and Consumer Acceptance

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    The performance of snake melon [Cucumis melo var. flexuosus (L.)] in organic farming was studied under high biotic and salt stress conditions. Soilborne diseases (mainly caused by Macrophomina phaseolina and Neocosmospora falciformis), combined with virus incidence [Watermelon mosaic virus (WMV), Zucchini yellow mosaic virus (ZYMV), and Tomato leaf curl New Delhi virus (ToLCNDV)] and Podosphaera xanthii attacks, reduced yield by more than 50%. Snake melon susceptibility to M. phaseolina and Monosporascus cannonballus was proved in pathogenicity tests, while it showed some degree of resistance to Neocosmospora keratoplastica and N. falciformis. On the contrary, salt stress had a minor impact, although a synergic effect was detected: yield losses caused by biotic stress increased dramatically when combined with salt stress. Under biotic stress, grafting onto the melon F1Pat81 and wild Cucumis rootstocks consistently reduced plant mortality in different agroecological conditions, with a better performance compared to classic Cucurbita commercial hybrids. Yield was even improved under saline conditions in grafted plants. A negative effect was detected, though, on consumer acceptability, especially with the use of Cucurbita rootstocks. Cucumis F1Pat81 rootstock minimized this side effect, which was probably related to changes in the profile of sugars, acids, and volatiles. Grafting affected sugars and organic acid contents, with this effect being more accentuated with the use of Cucurbita rootstocks than with Cucumis. In fact, the latter had a higher impact on the volatile organic compound profile than on sugar and acid profile, which may have resulted in a lower effect on consumer perception. The use of Cucumis rootstocks seems to be a strategy to enable organic farming production of snake melon targeted to high-quality markets in order to promote the cultivation of this neglected crop.

    Semiempirical in-cylinder pressure based model for NOx prediction oriented to control applications

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    This work describes the development of a fast NO X predictive model oriented to engine control in diesel engines. The in-cylinder pressure is the only instantaneous input signal required, along with several mean variables that are available in the ECU during normal engine operation. The proposed model is based on the instantaneous evolution of the heat release rate and the adiabatic flame temperature (both obtained among other parameters from the in-cylinder pressure evolution). Corrections for considering the NO X reduction due to the re-burning mechanism are also included. Finally, the model is used for providing a model-based correction of tabulated values for the NO X emission at the reference conditions. The model exhibits a good behaviour when varying exhaust gas recirculation rate, boost pressure and intake temperature, while changes in the engine speed and injection settings are considered in the tabulated values. Concerning the calculation time, the model is optimised by proposing simplified sub-models to calculate the heat release and the adiabatic flame temperature. The final result is suitable for real time applications since it takes less than a cycle to complete the NO X prediction.Guardiola García, C.; López Sánchez, JJ.; Martín Díaz, J.; García Sarmiento, D. (2011). Semiempirical in-cylinder pressure based model for NOx prediction oriented to control applications. Applied Thermal Engineering. 31(16):3275-3286. doi:10.1016/j.applthermaleng.2011.05.048S32753286311
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