449 research outputs found
Optimizing adipogenic transdifferentiation of bovine mesenchymal stem cells: a prominent role of ascorbic acid in FABP4 induction
Adipocyte differentiation of bovine adipose-derived stem cells (ASC) was induced by foetal bovine serum (FBS), biotin, pantothenic acid, insulin, rosiglitazone, dexamethasone and 3-isobutyl-1-methylxanthine, followed by incubation in different media to test the influence of ascorbic acid (AsA), bovine serum lipids (BSL), FBS, glucose and acetic acid on transdifferentiation into functional adipocytes. Moreover, different culture plate coatings (collagen-A, gelatin-A or poly-L-lysine) were tested. The differentiated ASC were subjected to Nile red staining, DAPI staining, immunocytochemistry and quantitative reverse transcription PCR (for NT5E, THY1, ENG, PDGFRα, FABP4, PPARγ, LPL, FAS, GLUT4). Nile red quantification showed a significant increase in the development of lipid droplets in treatments with AsA and BSL without FBS. The presence of BSL induced a prominent increase in FABP4 mRNA abundance and in FABP4 immunofluorescence signals in coincubation with AsA. The abundance of NT5E, ENG and THY1 mRNA decreased or tended to decrease in the absence of FBS, and ENG was additionally suppressed by AsA. DAPI fluorescence was higher in cells cultured in poly-L-lysine or gelatin-A coated wells. In additional experiments, the multi-lineage differentiation potential to osteoblasts was verified in medium containing ß-glycerophosphate, dexamethasone and 1,25-dihydroxyvitamin D3 using alizarin red staining. In conclusion, bovine ASC are capable of multi-lineage differentiation. Poly-L-lysine or gelatin-A coating, the absence of FBS, and the presence of BSL and AsA favour optimal transdifferentiation into adipocytes. AsA supports transdifferentiation via a unique role in FABP4 induction, but this is not linearly related to the primarily BSL-driven lipid accumulation
Investigating Piezochromic Properties of πconjugated Materials: a combined Raman and DFT Study
Π-conjugated materials have been studied for decades due to their great interest in organic electronics. Among them, piezochromic materials, which exhibit color changes resulting from external pressure or mechanical grinding, become very attractive from a scientific viewpoint owing to their potential applications as pressure-sensing and opticalrecording systems1. The main target of the present work is to develop a joint experimental and theoretical approach able to deliver crucial information for the understanding of the structural effects causing piezochromic changes. To this end, we will focus our attention on two families of -conjugated materials with potential application as sensors. The first one is a family of 9,10-Bis((E)-n(pyrid-2-yl)vinyl) anthracene, BPnVA (n=2 orto-,3 metha- and 4 para-) compounds, see Figure 1. Interestingly, these three compounds with varying position of the nitrogen on the external pyridyl group exhibit different molecular packing modes. Grinding and the application of external pressure on the powder also led to a strong change in their photoluminescence color.2 The second familiy is based on the N,N’-Bis-Boc-3,3’-di(pyren-1yl)-2,2’-biindole compound (compound 1c in Figure 1) which also shows photoluminescence under pressure application. However, the molecular packing induced by this phenomenon is still under study 3. In both cases, it will be also very interesting to determine how temperature affects the vibrational structure of these systems.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Efectos de la realización de un megaevento deportivo sobre una economía local. El caso de los Juegos Mundiales 2013 Cali
Propósito – En el artículo se presenta una síntesis del impacto sobre la producción y el empleo generado por
la realización de un megaevento deportivo en la ciudad de Cali, Colombia.
Diseño/metodología/enfoque – El impacto se estima a través de los efectos sistemáticos producidos por
las actividades de inversión/gasto de los agentes identificados y los consecuentes efectos multiplicadores
capturados a partir de un modelo insumo-producto.
Hallazgos – La realización de los Juegos Mundiales significó un nuevo flujo de ingreso monetario a la
ciudad de Cali, de 101.036 million pesos (≡US$53.4 mill.) and 9.598 jobs were created (≡7,711 full-time jobs). Additionally, 2,174 foreign tourists and 11,250 national tourists were attracted to the city.
Originality/value
The article contributes with innovative aspects methodologically speaking, useful for future studies of economic impact in cities with low tourism located in developing countrie
Clonal spread of Klebsiella pneumoniae producing OXA-1 betalactamase in a Spanish hospital
Multi-drug resistant Klebsiella pneumoniae isolates are associated with nosocomial infections, in which colonized patients act as a reservoir and source of cross-infection for other patients. In this study, the antimicrobial susceptibility of K. pneumoniae was tested by microdilution using the commercial method MicroScan (Siemens). The genetic relatedness of K. pneumoniae strains was determined by pulsed field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). PCR experiments were carried out to obtain primer sets and positive PCR products were purified and sequenced. From May 2007 until December 2009, 98 clonally related K. pneumoniae isolates were detected from clinical samples of 38 patients admitted to the University Hospital of Bellvitge, Barcelona, Spain, including 27 admitted to the intensive care unit (ICU). The most important sources of the isolates were: lower respiratory tract (n = 12), urine (n = 12), and blood (n = 11). The strains were resistant to amoxicillin/clavulanic acid, piperacillin/tazobactam, tobramycin, amikacin, and ciprofloxacin, and had diminished susceptibility to cefepime. All the isolates shared a common PFGE pattern related to sequence type 14 after MLST analysis. In K. pneumoniae isolates and their transconjugants, the blaOXA-1 gene was located in the variable region of a class I integron that also contains the aac(6′)Ib-cr gene. Sequencing of the quinolone resistance determinant regions of gyrA and parC revealed a S83F change in GyrA and no changes in ParC. [Int Microbiol 2013; 16(4):227-233]Keywords: Klebsiella pneumoniae · sequence type ST14 · gene blaOXA-1 · integrons · nosocomial outbreak
Multiferroism and enhancement of material properties across the morphotropic phase boundary of BiFeO3-PbTiO3
Strong phase-change magnetoelectric responses have been anticipated by a first-principles investigation of phases in the perovskite BiFeO 3-BiCoO3 solid solution, specifically at the morphotropic phase boundary (MPB) between the multiferroic rhombohedral and tetragonal polymorphs. This might be a general property of multiferroic MPBs and a novel promising approach for room temperature magnetoelectricity, which requires the identification of suitable material systems. We present here a comprehensive description of the electrical and electromechanical properties across one such system; the perovskite BiFeO3-PbTiO3 solid solution. All the temperature dependence of dielectric permittivity, ferroelectric hysteresis loops, and piezoelectric coefficients have been obtained, and are discussed in relation to the previously reported perovskite structural evolution. Results show ceramic materials to be very promising for ferroelectric random access memories (remnant polarization as high as 63 μC cm-2 with a comparatively low coercive field of 4.5 kV mm-1 for MPB compositions) and high temperature electromechanical transduction (crystal piezoelectric coefficient of 87 pC N-1 with a Curie temperature above 873 K). Moreover, the occurrence of phase changes between the monoclinic and tetragonal polymorphs under high electric fields is indicated, while the canted antiferromagnetic character of the phases involved is corroborated. © 2014 AIP Publishing LLC.Funded by MINECO (Spain) through the MAT2011-23709 project. Dr. H. Amorín thanks financial support by MICINN Ramón y Cajal Programme (RYC-2008-03247). Ms. C. Correas and Ms. C. M. Fernández-Posada also thank the specific financial support of FPI Programme (BES-2008-005409 and BES-2012-053017, respectively).Peer Reviewe
Piezochromic properties of a D-A-D platform: A joint experimental and theoretical perspective
Organic π-conjugated molecules with mechanochromic luminescence properties have attracted great interest in the last two decades due to their numerous applications in the optoelectronic field, such as sensors, probes and security inks. Materials that modify their colour under pressure are known as piezochromic materials. Usually, this variation is provoked by changes in the molecular structure, for example, crystal-to-amorphous phase transitions, modifications in dihedral angles or bond distances, and intermolecular interactions. The molecule proposed in this study is a TADF (Thermally activated delayed fluorescence) U-shaped molecule composed by two donors and one acceptor (D-A-D) units with a π-conjugated skeleton [1]. It was synthetized as a powder which under different crystallization methods gives rise to different conformers varying the dihedral angle of the bond that links the D and A units. The donors are two phenothiazine units and the acceptor is a dibenzo[a,j]phenazine unit located in the central core. Two different conformers have been analysed: the quasi equatorial - quasi equatorial (denoted as 1R) and the quasi axial - quasi axial (denoted as 1Y). In this project, we study the configurational changes triggering the piezochromic effects combining density functional theory (DFT) calculations with Raman spectroscopy experiments of the 1R and 1Y conformers during heating or in compression via a sapphire anvil cell [2]. Both show pressure and temperature dependence properties. Besides, these changes are reversible meaning that when the stimuli stop they revert to its original conformation. When these molecules are exposed to different ambient (like pressure or temperature variations) they evolved to a third conformer with an intermediate dihedral angle that results in different Raman, emission and absorption behaviour.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Hibridación de tecnologías renovables para adaptar la generación a la curva de demanda
Actualmente el equilibrio entre la oferta y la demanda eléctrica se sucede en tiempo real, y el sistema soporta unos sobrecostes derivados de la sobreinstalación de potencia no gestionable. El presente trabajo analizará la posibilidad de adaptar la generación de energía renovable a una curva previamente establecida. Para ello, el ejercicio va a satisfacer una demanda, atendiendo a la actual configuración de redes eléctricas, como un paso intermedio entre la generación centralizada y la generación distribuida. A partir de una demanda previamente escalada, se va a garantizar la máxima energía posible ajustada a la curva de demanda, mediante un sistema híbrido fotovoltaico y eólico, compensando excesos y carencias mediante un almacenamiento. El trabajo se realizará a partir de datos de producción horarios extraídos de instalaciones den operación, y la curva de demanda será la publicada por Red Eléctrica de España. El alcance del trabajo se detalla a continuación: 1. Ajustar la generación de electricidad de origen fotovoltaico a la curva de demanda, y calcular el porcentaje de demanda satisfecha. 2. Ajustar la generación de electricidad de origen eólico a la curva de demanda y calcular el porcentaje de demanda satisfecha. 3. Generar conjuntamente eólica y fotovoltaica de acuerdo a la curva de demanda. Analizar su compatibilidad y calcular el porcentaje de demanda satisfecha. 4. Implementar un almacenamiento y cuantificar su mejora. 5. Incorporar un grupo biodiesel al sistema formado por la hibridación y el almacenamiento, con el objetivo de intentar cubrir la totalidad de la demanda. 6. Elaborar las conclusiones obtenidas acerca de la posibilidad de satisfacer o no la demanda. Calcular la energía de exceso, las horas de funcionamiento y la viabilidad económica de la instalación. 7. Por último, realizar un pequeño análisis de las oportunidades de mercado
Hospitalització urgent per lesions no intencionades a Catalunya lʼany 2010
Lesions; Col·lisions; CaigudesInjuries; Collisions; FallsLesiones; Colisiones; CaídasAquest treball té com a objectiu mostrar la magnitud i les característiques principals de les lesions no intencionades que van causar lʼingrés de persones en un hospital dʼaguts de Catalunya lʼany 2010.Este trabajo tiene como objetivo mostrar la magnitud y las características principales de las lesiones no intencionadas que causaron ingreso de personas en un hospital de agudos de Cataluña el año 2010.The aims of this work are to show the magnitude and the main features of unintentional injuries that caused hospital admission of people in Catalonia the year 2010
Pvlearning: herramienta web para la enseñanza de la energía solar fotovoltaica
En este trabajo, se describe la web www.pvlearning.com, desarrollada en la Universidad de Alcalá para la enseñanza de la energía solar fotovoltaica. PVLEARNING asiste al alumno en la realización de tareas como la evaluación de la radiación solar disponible, la selección de los componentes del sistema, la configuración de éstos y la estimación del rendimiento global y la energía total producida. Frente a otros programas de simulación, la plataforma presenta la novedad de estar enfocada al aprendizaje de la ingeniería de proyectos, sin por ello perder todo el rigor y la funcionalidad necesarios en este tipo de simuladores.This work describes the web www.pvlearning.com, which has been developed at the Universidad de
Alcalá for photovoltaic solar energy teaching. PVLEARNING assists the student in tasks such as the
evaluation of the solar radiation, the selection of the system components, the configuration of the solar
generator and the estimation of the performance ratio, the final yield and the total energy production.
In contrast to other simulation programs, the platform has the novelty of being focused on the learning of
project engineering, without losing the accuracy and functionality which is required in this kind of simulator
Ecología, sistemática y distribución de foraminíferos bentónicos entre la desembocadura del río sinú y coveñas, caribe colombiano
En cuatro ecosistemas diferentes: estuario, laguna costera, zona litoral y zona infralitoral, se identificó una microfauna constituida por 75 taxa, de los cuales un 14.6110estuvo representado en la biocenosis. Se encontró que Ammonia beccarii es la especie de más amplia distribución en todos los ambientes estudiados.Los grupos faunísticos se relacionaron con algunos parámetros ecológicos.En el ecosistema marino infralitoral se estableció un predominio de género Quinqueloculina en sedimentos arenosos y del genera Nonionella, en sedimentos limo-arcillosos. Quinqueloculina distorqueata Cushman, Q. ferussacii d'Orbigny y Fursenkoina fusiformis (Williamson) son reportadas por primera vez en el Caribe
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