Self-assembly of Chemically Programmed Amphiphiles into Aqueous Nanotubes with a Lipophilic Lumen.

The creation of complex hollow nanostructures with precise control over size and shape represents a great challenge in supramolecular soft materials. Here, we have further developed a bioinspired methodology for the formation of aqueous nanotubes of well-defined dimensions and pore coating through the self-assembly of amphiphiles that are chemically programmed with complementary nucleobases. These nanotubes are endowed with a hydrophobic lumen, whose diameter can be expanded as a function of the monomer length, in which apolar dyes can be efficiently encapsulated.

Highly efficient grafting of hetero-complementary amidinium and carboxylate hydrogen-bonding/ionic pairs onto polymer surfaces.

We describe a grafting methodology, based on thiol-fluoroarene chemistry, to efficiently incorporate complementary hydrogen-bonding carboxylate and amidinium groups into polymer backbones. The process was optimized both in solution and on the surface of processed films, with the aim to produce materials showing hetero-complementary adhesion.

Caveolin-1 protects endothelial cells from extensive expansion of transcellular tunnel by stiffening the plasma membrane.

Large transcellular pores elicited by bacterial mono-ADP-ribosyltransferase (mART) exotoxins inhibiting the small RhoA GTPase compromise the endothelial barrier. Recent advances in biophysical modeling point toward membrane tension and bending rigidity as the minimal set of mechanical parameters determining the nucleation and maximal size of transendothelial cell macroaperture (TEM) tunnels induced by bacterial RhoA-targeting mART exotoxins. We report that cellular depletion of caveolin-1, the membrane-embedded building block of caveolae, and depletion of cavin-1, the master regulator of caveolae invaginations, increase the number of TEMs per cell. The enhanced occurrence of TEM nucleation events correlates with a reduction in cell height due to the increase in cell spreading and decrease in cell volume, which, together with the disruption of RhoA-driven F-actin meshwork, favor membrane apposition for TEM nucleation. Strikingly, caveolin-1 specifically controls the opening speed of TEMs, leading to their dramatic 5.4-fold larger widening. Consistent with the increase in TEM density and width in siCAV1 cells, we record a higher lethality in CAV1 KO mice subjected to a catalytically active mART exotoxin targeting RhoA during staphylococcal bloodstream infection. Combined theoretical modeling with independent biophysical measurements of plasma membrane bending rigidity points toward a specific contribution of caveolin-1 to membrane stiffening in addition to the role of cavin-1/caveolin-1-dependent caveolae in the control of membrane tension homeostasis.

Aprendizaje Multimedia y el efecto de las modalidades instruccionales / Multimedia learning and the effect of instructional modalities

El aprendizaje multimedia es un fenómeno estrechamente vinculado con el uso de tecnologías de la información y comunicación en entornos educativos. Diferentes posturas han surgido para abordar sus características, siendo la de Mayer la más destacada. Se realizó una investigación de tipo documental conocida como meta-análisis, la cual consiste en una revisión sistemática cualitativa o cuantitativa de un conjunto de informes o artículos de investigación, realizados con el ánimo de estudiar el efecto de una variable en particular; El presente estudio se realizó de forma cuantitativa mediante un estadístico conocido como el coeficiente de Cohen (d) a través del cual se puede determinar cuál es la magnitud del efecto de una variable (Nulo, Bajo, moderado, alto). Como resultado de este proceso se encuentra que la modalidad instruccional tiene un efecto alto (44% de las mediciones consultadas en las diferentes publicaciones), así como que la investigación en esta área ha ido disminuyendo en los últimos cinco años. Finalmente se encuentra un dato muy interesante, según el cual dentro de las publicaciones analizadas, solamente una se realizó en tareas de memoria implícita

Multimedia learning is a phenomenon closely linked to the use of information and communication technologies in educational environments. Different approaches have arisen to address its characteristics, being Mayer's position the most outstanding. A documentary investigation was carried out which consisted of a quantitative systematic review of Cohen's Kappa coefficient (d) through which the magnitude of the effect of a variable can be determined (null, low, moderate, high). Results suggest that the effect of instructional modality is high (44% of the measurements consulted in different publications) and that research in this area decreased in the observation window. There is a very interesting fact: among all the publications analyzed only one was on implicit memory tasks, this opens up the possibility of working in this field