Modelación numérica de deslizamientos de ladera en embalses mediante el método de partículas y elementos finitos (PFEM)

Se presentan resultados obtenidos mediante la aplicación del MétododePartículasyElementosFinitos (PFEM) en la simulación dedeslizamientosdeladeraenembalses. Es un fenómeno complejo, por la interacción entre el material deslizado, la masa de agua del embalse, yel conjunto formado por el vaso y la presa. PFEM es un esquema numérico original con el que se ha afrontado con éxito la resolución de problemas de interacción fluido-estructura. Combina un enfoque Lagrangiano con la resolución de las ecuaciones deelementosfinitosmediante la generación de una malla, que se actualiza en cada paso de tiempo. Se presentan resultados de casos de validación en los que se han reproducido ensayos en laboratorio existentes en la bibliografía técnica. Se muestran también otros cálculos más complejos, sobre la cartografía a escala real de un embalse, donde se aprecia el fenómeno de generación de la ola, su propagación por el embalse y la afección a la presa. Por último, se ha modelado el deslizamiento ocurrido en 1958 en la bahía de Lituya (Alaska), enel que la caída de 90 millones de toneladas de roca produjo una ola que alcanzó una sobreelevación máxima de 524 m en la ladera opuesta. Los resultados permiten afirmar que PFEM puede ser una herramienta útil enel análisis de riesgos frente a este tipo de fenómenos, ofreciendo una buena aproximación de las afecciones potenciale

Nanomechanical sensors: Measuring a response in blood

Nanomechanical cantilevers can determine the concentration of active drugs in human serum

Relativistic Structure of the Nucleon Self-Energy in Asymmetric Nuclei

The Dirac structure of the nucleon self-energy in asymmetric nuclear matter cannot reliably be deduced from the momentum dependence of the single-particle energies. It is demonstrated that such attempts yield an isospin dependence with even a wrong sign. Relativistic studies of finite nuclei have been based on such studies of asymmetric nuclear matter. The effects of these isospin components on the results for finite nuclei are investigated.Comment: 9 pages, Latex 4 figures include

Macrophage cholesterol efflux correlates with lipoprotein subclass distribution and risk of obstructive coronary artery disease in patients undergoing coronary angiography

<p>Abstract</p> <p>Background</p> <p>Studies in patients with low HDL have suggested that impaired cellular cholesterol efflux is a heritable phenotype increasing atherosclerosis risk. Less is known about the association of macrophage cholesterol efflux with lipid profiles and CAD risk in normolipidemic subjects. We have therefore measured macrophage cholesterol efflux in142 normolipidemic subjects undergoing coronary angiography.</p> <p>Methods</p> <p>Monocytes isolated from blood samples of patients scheduled for cardiac catheterization were differentiated into macrophages over seven days. Isotopic cholesterol efflux to exogenously added apolipoprotein A-I and HDL2 was measured. Quantitative cholesterol efflux from macrophages was correlated with lipoprotein subclass distribution in plasma from the same individuals measured by NMR-spectroscopy of lipids and with the extent of coronary artery disease seen on coronary angiography.</p> <p>Results</p> <p>Macrophage cholesterol efflux was positively correlated with particle concentration of smaller HDL and LDL particles but not with total plasma concentrations of HDL or LDL-cholesterol. We observed an inverse relationship between macrophage cholesterol efflux and the concntration of larger and triglyceride rich particles (VLDL, chylomicrons). Subjects with significant stenosis on coronary angiography had lower cholesterol efflux from macrophages compared to individuals without significant stenosis (adjusted p = 0.02).</p> <p>Conclusion</p> <p>Macrophage cholesterol efflux is inversely correlated with lipoprotein particle size and risk of CAD.</p

Real-time DNA microarray analysis

We present a quantification method for affinity-based DNA microarrays which is based on the real-time measurements of hybridization kinetics. This method, i.e. real-time DNA microarrays, enhances the detection dynamic range of conventional systems by being impervious to probe saturation in the capturing spots, washing artifacts, microarray spot-to-spot variations, and other signal amplitude-affecting non-idealities. We demonstrate in both theory and practice that the time-constant of target capturing in microarrays, similar to all affinity-based biosensors, is inversely proportional to the concentration of the target analyte, which we subsequently use as the fundamental parameter to estimate the concentration of the analytes. Furthermore, to empirically validate the capabilities of this method in practical applications, we present a FRET-based assay which enables the real-time detection in gene expression DNA microarrays

All-electronic terahertz nanoscopy

Probing conductivity in a contactless way with nanoscale resolution is a pressing demand in such active fields as quantum materials, superconductivity, and molecular electronics. Here, we demonstrate a laser-and cryogen-free microwave-technology-based scattering-type scanning near-field optical microscope powered by an easily aligned free-space beam with a tunable frequency up to 0.75 THz. It uses Schottky diode components to record background-free amplitude and phase nano-images, for the first time in the terahertz range, which is uniquely sensitive for assessing conduction phenomena. Images of Si with doped nanostructures prove a conductance sensitivity corresponding to 10(16) cm(-3) mobile carriers, at 50 nm spatial resolution