The chemistry of La on the Si(001) surface

This paper reports state-of-the-art electronic structure calculations of La adsorption on the Si(001) surface. We predict La chains in the low coverage limit, which condense in a stable phase at a coverage of 1/5 monolayer. At 1/3 monolayer we predict a chemically rather inert, stable phase. La changes its oxidation state from La(3+) at lower coverages to La(2+) at coverages beyond 1/3 monolayer. In the latter oxidation state, one electron resides in a state with a considerable contribution from La-d and f states.Comment: 10 pages, 13 figures, 3 table

Research on classroom practice: A monograph for topic study group 24, ICME 11 - The introductory chapter

published_or_final_versionThe 11th International Congress on Mathematical Education (ICME 11), Monterrey, Mexico, 6-13 July 2008. In Quaderni di Ricerca in Didattica, 2009, n. S4, p. 1-

Electrophoretic deposition of nanostructured-TiO2/chitosan composite coatings on stainless steel

Novel chitosan composite coatings containing titania nanoparticles (n-TiO2) for biomedical applications were developed by electrophoretic deposition (EPD) from ethanol–water suspensions. The optimal ethanol–water ratio was studied in order to avoid bubble formation during the EPD process and to ensure homogeneous coatings. Different n-TiO2 contents (0.5–10 g L−1) were studied for a fixed chitosan concentration (0.5 g L−1) and the properties of the electrophoretic coatings obtained were characterized. Coating composition was analyzed by thermogravimetric analysis (TG), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analysis. Scanning electron microscopy (SEM) was employed to study both the surface and the cross section morphology of the coatings, and the thicknesses (2–6 μm) of the obtained coatings were correlated with the initial ceramic content. Contact angle measurements, as a preliminary study to predict hypothetic protein attachment on the coatings, were performed for different samples and the influence of a second chitosan layer on top of the coatings was also tested. Finally, the electrochemical behavior of the coatings, evaluated by polarization curves in DMEM at 37 °C, was studied in order to assess the corrosion resistance provided by the n-TiO2/chitosan coatings

N-Glycosylation affects humoral immune response of Her1 cancer vaccine

Vaccine preparations based on the extracellular domain of Her1 protein (Her1-ECD) have demonstrated, in vitro and in vivo, a potent antimetastatic effect on EGFR+ Lewis lung carcinoma model, while associated side effects were absent. The Her1-ECD is a glycoprotein with a molecular weight of 105 kDa and has 11 potencial sites for N-glycosylation. Glycosylation is a post-translational modification that can affect the protein folding, stability, regulates protein half-life, immunogenecity, biological activity and other functions. In this work, the N-glycosylation Her1-ECD was preliminarily characterized by SDS-PAGE, glycan differentiation by lectin and normal phase chromatography. Finally, the biological activity of the glycosylated and totally deglycosylated Her1-ECD protein was compared. As results were obtained that N-glycosylation profile of Her1-ECD is composed of high mannose, hybrid and complex N-glycans types, and Her1-ECD glycosylation modifies the humoral immune response, measured as antibody titers, recognition of EGFR in A431 cell line and cell cycle arrest

Impactos y adaptación al cambio climático en el Puerto de Veracruz / Impacts and adaptation to climate change in Veracruz

En este ensayo se disertan los impactos económicos, sociales y culturales que puede sufrir el puerto de Veracruz en caso de que el nivel del mar incremente súbitamente en 5 metros su nivel. Nuestro objetivo es geografizar los grupos vulnerables que se encuentran dentro de la zona de peligro. Es de advertir que el tratamiento cuantitativo proviene de micro-datos, mientras que con el trabajo de campo realizado a nivel local se buscó darle una representación cualitativa a nuestro enfoque interdisciplinario.   This article outlines the economic, social and cultural impacts that may suffer the port of Veracruz in case the sea level suddenly increase 5 meters their level. Our goal is zoning and caracterization of vulnerable groups that are within the danger zone. The quantitative treatment was derived from micro-data, while the fieldwork locally sought to give a qualitative representation to our interdisciplinary approach

Priming by Chemokines Restricts Lateral Mobility of the Adhesion Receptor LFA-1 and Restores Adhesion to ICAM-1 Nano-Aggregates on Human Mature Dendritic Cells

LFA-1 is a leukocyte specific β2 integrin that plays a major role in regulating adhesion and migration of different immune cells. Recent data suggest that LFA-1 on mature dendritic cells (mDCs) may function as a chemokine-inducible anchor during homing of DCs through the afferent lymphatics into the lymph nodes, by transiently switching its molecular conformational state. However, the role of LFA-1 mobility in this process is not yet known, despite that the importance of lateral organization and dynamics for LFA-1-mediated adhesion regulation is broadly recognized. Using single particle tracking approaches we here show that LFA-1 exhibits higher mobility on resting mDCs compared to monocytes. Lymphoid chemokine CCL21 stimulation of the LFA-1 high affinity state on mDCs, led to a significant reduction of mobility and an increase on the fraction of stationary receptors, consistent with re-activation of the receptor. Addition of soluble monomeric ICAM-1 in the presence of CCL21 did not alter the diffusion profile of LFA-1 while soluble ICAM-1 nano-aggregates in the presence of CCL21 further reduced LFA-1 mobility and readily bound to the receptor. Overall, our results emphasize the importance of LFA-1 lateral mobility across the membrane on the regulation of integrin activation and its function as adhesion receptor. Importantly, our data show that chemokines alone are not sufficient to trigger the high affinity state of the integrin based on the strict definition that affinity refers to the adhesion capacity of a single receptor to its ligand in solution. Instead our data indicate that nanoclustering of the receptor, induced by multi-ligand binding, is required to maintain stable cell adhesion once LFA-1 high affinity state is transiently triggered by inside-out signals.Peer ReviewedPostprint (published version