Search results for "Roca"
showing 10 items of 1893 documents
Extraordinary tuning of a nanocavity by a near-field probe
2011
Abstract We report here an experimental observation of an extraordinary near-field interaction between a local probe and a small-volume solid-state nanocavity. We directly compare the normally observed near-field interaction regime driven by the perturbation theory and then report the extraordinary interaction regime. Subsequently, we show that the cavity can take up to 2 min to recover from this interaction after removing the probe and that leads to an extraordinary blue-shift of the cavity resonance wavelength (∼15 nm) which depends on the probe motion above the cavity and not the position. The reasons for this effect are not fully understood yet but we try to give some explanations.
Intramolecular electronic excitation energy transfer in donor∕acceptor dyads studied by time and frequency resolved single molecule spectroscopy
2008
Electronic excitation energy transfer has been studied by single molecule spectroscopy in donor/acceptor dyads composed of a perylenediimide donor and a terrylenediimide acceptor linked by oligo(phenylene) bridges of two different lengths. For the shorter bridge (three phenylene units) energy is transferred almost quantitatively from the donor to the acceptor, while for the longer bridge (seven phenylene units) energy transfer is less efficient as indicated by the occurrence of donor and acceptor emission. To determine energy transfer rates and efficiencies at the single molecule level, several methods have been employed. These comprise time-correlated single photon counting techniques at r…
Flavonoids from Erythrina schliebenii
2017
Prenylated and O-methylflavonoids including one new pterocarpan (1), three new isoflavones (2–4), and nineteen known natural products (5–23) were isolated and identified from the root, stem bark, and leaf extracts of Erythrina schliebenii. The crude extracts and their constituents were evaluated for antitubercular activity against Mycobacterium tuberculosis (H37Rv strain), showing MICs of 32–64 μg mL–1 and 36.9–101.8 μM, respectively. Evaluation of their toxicity against the aggressive human breast cancer cell line MDA-MB-231 indicated EC50 values of 13.0–290.6 μM (pure compounds) and 38.3 to >100 μg mL–1 (crude extracts).
Análisis de señales biomédicas para aplicación de terapias en la fibrilación ventricular cardiaca
2017
La muerte súbita es una muerte natural, inesperada y rápida en un tiempo límite de 24 horas después del comienzo de un proceso patológico. Las causas más comunes de la muerte súbita son las enfermedades Cardiovasculares (ECV) que resultan estar entre las principales causas de muerte en todo el mundo. En 2012, la Organización Mundial de la Salud (OMS) registró 17,5 millones de muertes por ECV, que representan el 31 % de todas las muertes registradas en el mundo . Una de las enfermedades cardiovasculares con mayor mortalidad es la Fibrilación Ventricular (FV), que es una arritmia cardíaca producida por una actividad eléctrica desorganizada del corazón. Durante la FV, los ventrículos se contra…
Un testigo del arte barroco "novator" valenciano de "La Vall de Gallinera": la iglesia parroquial de San Miguel de Benissivà
2002
El estudio nos presenta una muestra de recuperación de artesanías tradicionales en el medio rural como proyecto de enseñanza-aprendizaje de la Universitat de València y su Área de Conservació del Patrimoni Cultural, desde unos análisis histórico-material, histórico-artístico y técnico, en torno a la intervención llevada a cabo en la iglesia de San Miguel de Benissivà de Alicante. Buscando su valoración dentro del conjunto patrimonial al cual pertenece, se acomete una investigación sobre dicho templo y sus transformaciones, sus orígenes, evolución y creadores (entendidos dentro de la etapa artística valenciana de esplendor barroco y clasicismo matemático en la que se encuentran inmiscuidos),…
Assessment of Thoracic Aortic Dimensions in an Experimental Setting: Comparison of Different Unenhanced Magnetic Resonance Angiography Techniques Wit…
2008
PURPOSE To compare different unenhanced magnetic resonance angiography (MRA) techniques for quantitative evaluation of vessel lumen in an experimental setting in young pigs whose dimensions allow for a comparison with a pediatric population. MATERIAL AND METHODS Magnetic resonance imaging was performed in 5 healthy ventilated pigs at 1.5 T. Three different electrocardiogram (ECG)-triggered sequences were applied for MRA: [TSE-Db] T2-weighted dark-blood TurboSpinEcho (2.0 x 1.1 x 4 mm3); [trueFISP] 2D-steady-state-free-precession (2.2 x 1.8 x 2 mm3); [NAV] respiratory-gated, T2-prepared 3D-trueFISP (1.3 x 1.3 x 1.3 mm3). ECG-gated-CT angiography (CTA) (16-row CT, 1 mm collimation) served as …
Incidence, Predictive Factors, and Prognostic Impact of Silent Atrial Fibrillation After Transcatheter Aortic Valve Implantation.
2018
New onset atrial fibrillation post-transcatheter aortic valve implantation (TAVI) is common and is associated with adverse outcomes. However, silent atrial fibrillation (AF) is poorly documented in the context. This study sought to evaluate the incidence, predictive factors, and prognostic value of Silent AF post-TAVI. All the consecutive patients with TAVI were prospectively analyzed by continuous electrocardiogram monitoring≥48 hours after implantation. Silent AF was defined as asymptomatic episodes lasting at least 30 seconds. The population was divided into 3 groups: history of AF, no-AF, and silent AF. Among the 206 patients implanted with TAVI, 19 (16.1%) developed silent AF. Compared…
Knock-down of the oxysterol receptor LXRα impairs cholesterol efflux in human primary macrophages: lack of compensation by LXRβ activation.
2012
Liver X Receptors (LXRs) α and β are oxysterol-activated nuclear receptors involved in the control of lipid metabolism and inflammation. Pharmacological activation of LXR is promising in the treatment of atherosclerosis since it can promote cholesterol efflux from macrophages and prevent foam cell formation. However, the development of LXR agonists has been limited by undesirable side-effects such as hepatic steatosis mediated by LXRα activation. Therefore, it has been proposed that targeting LXRα activators to extrahepatic tissues or using LXRβ-specific activators could be used as alternative strategies. It is not clear whether these molecules will retain the full atheroprotective potentia…
Polycyclic aromatic hydrocarbons and trace metal contamination of coastal sediment and biota from Togo
2011
The state of contamination of tropical environments, particularly in Africa, remains a relatively under explored subject. Here, we determined polycyclic aromatic hydrocarbon (PAH) and trace metal concentrations in coastal sediment and biota samples (fish and mussels) from Togo (West Africa). In the sediments, the ∑21 PAH concentrations ranged from4 ng g(-1) to 257 ng g(-1), averaging 92 ng g(-1). Concentration ratios of low molecular weight PAHs (2-3 rings) versus high molecular weight PAHs (≥4 rings) were always lower than 1 (ranging from 0.08 to 0.46) indicating that high molecular weight PAHs were dominant in all sediment samples, and that PAHs originated mainly from anthropogenic combus…
Advances in the knowledge of South African Riella (Sphaerocarpales) and a new endemic species, Riella trigonospora
2014
Cultures of soil sediments collected in June 2012 from saltpans and vleis from five South African localities have revealed two new, geographically distant, populations of the endemic Riella alatospora, confirmed the presence of Riella purpureospora from Blouvlei in the Cape Town area and uncovered a new endemic species, Riella trigonospora. The new species obtained from cultures from five sampled localities is described and illustrated. It is dioicous and characterised by acuminate to rostrate, papillose involucres and by a unique spore morphology. The spores are dark purple, as in R. purpureospora, and have an irregular discontinuous wing at the equatorial plane, which suggests a morpholog…