David Sánchez

Long-term intake of a milk casein hydrolysate attenuates the development of hypertension and involves cardiovascular benefits

Essential hypertension is considered a serious health problem and diet can play an important role in its prevention and treatment. The aim of this study was to evaluate the effect of the long-term intake of a product based on milk casein hydrolysate on the development of hypertension in spontaneously hypertensive rats (SHR). A daily dose of 800 mg/kg body weight of the casein hydrolysate product was administered dissolved in drinking water during 6 weeks. Systolic and diastolic blood pressures were measured weekly by the tail-cuff method. Endothelial function in aorta and mesenteric segments, left ventricular hypertrophy, endothelial nitric oxide synthase (eNOS) expression in aorta and plasmatic angiotensin conversion enzyme (ACE) activity were also evaluated at the end of treatment. The development of hypertension was attenuated in the group treated with the casein hydrolysate product; in this sense the systolic blood pressure increased 33±3 mmHg in control group and only 18±5 mmHg in the treated group during the experimental period. In addition, the treatment improved aorta and mesenteric acetylcholine relaxations and increased the eNOS expression in aorta. Left ventricular hypertrophy decreased in treated SHR accompanied by a significant decrease in interstitial fibrosis. These results warrant evaluation in humans to determine if the product based on a casein hydrolysate could be used as a functional food ingredient to prevent blood pressure increased with additional cardiovascular benefits.

How to distinguish between interacting and noninteracting molecules in tunnel junctions

Recent experiments demonstrate a temperature control of the electric conduction through a ferrocene-based molecular junction. Here we examine the results in view of determining means to distinguish between transport through single-particle molecular levels or via transport channels split by Coulomb repulsion. Both transport mechanisms are similar in molecular junctions given the similarities between molecular intralevel energies and the charging energy. We propose an experimentally testable way to identify the main transport process. By applying a magnetic field to the molecule, we observe that an interacting theory predicts a shift of the conductance resonances of the molecule whereas in the noninteracting case each resonance is split into two peaks. The interaction model works well in explaining our experimental results obtained in a ferrocene-based single-molecule junction, where the charge degeneracy peaks shift (but do not split) under the action of an applied 7-Tesla magnetic field. This method is useful for a proper characterization of the transport properties of molecular tunnel junctions.

De la galaxia Gutenberg a la galaxia internet : la itinerancia en la lectura

La lectura, como la escritura, es el instrumento por antonomasia de la comunicacion humana, si exceptuamos al lenguaje hablado. Como el lenguaje, la escritura y, por tanto, la lectura, cambian de forma en el tiempo, en razon de elementos que trascienden el mero acto de leer. En nuestra epoca, la lectura, ya sea a traves del papel o de cualquier tecnologia digital, evidencia un nuevo canon que aqui caracterizamos principalmente por su flexibilidad. Este articulo aborda el modo en que la lectura se construye activamente a traves de los procesos de cambio social, convirtiendose en si misma en una ventana a traves de la cual conocer como es una sociedad.