Raman response of Stage-1 graphite intercalation compounds revisited

We present a detailed in-situ Raman analysis of stage-1 KC8, CaC6, and LiC6 graphite intercalation compounds (GIC) to unravel their intrinsic finger print. Four main components were found between 1200 cm-1 and 1700 cm-1, and each of them were assigned to a corresponding vibrational mode. From a detailed line shape analysis of the intrinsic Fano-lines of the G- and D-line response we precisely determine the position ({\omega}ph), line width ({\Gamma}ph) and asymmetry (q) from each component. The comparison to the theoretical calculated line width and position of each component allow us to extract the electron-phonon coupling constant of these compounds. A coupling constant {\lambda}ph < 0.06 was obtained. This highlights that Raman active modes alone are not sufficient to explain the superconductivity within the electron-phonon coupling mechanism in CaC6 and KC8.Comment: 6 pages, 3 figures, 2 table

Novel SCAMPs Lacking NPF Repeats: Ubiquitous and Synaptic Vesicle-Specific Forms Implicate SCAMPs in Multiple Membrane- Trafficking Functions

In vertebrates, secretory carrier membrane proteins (SCAMPs) 1–3 constitute a family of putative membrane-trafficking proteins composed of cytoplasmic N-terminal sequences with NPF repeats, four central transmembrane regions (TMRs), and a cytoplasmic tail. SCAMPs probably function in endocytosis by recruiting EH-domain proteins to the N-terminal NPF repeats but may have additional functions mediated by their other sequences. We now demonstrate that SCAMPs form a much larger and more heterogeneous protein family than envisioned previously, with an evolutionary conservation extending to invertebrates and plants. Two novel vertebrate SCAMPs (SCAMPs 4 and 5), single SCAMP genes in Caenorhabditis elegans and Drosophila melanogaster, and multiple SCAMPs in Arabidopsis thaliana were identified. Interestingly, the novel SCAMPs 4 and 5 lack the N-terminal NPF repeats that are highly conserved in all other SCAMPs. RNA and Western blotting experiments showed that SCAMPs 1–4 are ubiquitously coexpressed, whereas SCAMP 5 is only detectable in brain where it is expressed late in development coincident with the elaboration of mature synapses. Immunocytochemistry revealed that SCAMP 5 exhibits a synaptic localization, and subcellular fractionations demonstrated that SCAMP 5 is highly enriched in synaptic vesicles. Our studies characterize SCAMPs as a heterogeneous family of putative trafficking proteins composed of three isoforms that are primarily synthesized outside of neurons (SCAMPs 2–4), one isoform that is ubiquitously expressed but highly concentrated on synaptic vesicles (SCAMP 1), and one brain-specific isoform primarily localized to synaptic vesicles (SCAMP 5). The conservation of the TMRs in all SCAMPs with the variable presence of N-terminal NPF repeats suggests that in addition to the role of some SCAMPs in endocytosis mediated by their NPF repeats, all SCAMPs perform a “core” function in membrane traffic mediated by their TMRs

A Poglut1 mutation causes a muscular dystrophy with reduced Notch signaling and satellite cell loss

Skeletal muscle regeneration by muscle satellite cells is a physiological mechanism activated upon muscle damage and regulated by Notch signaling. In a family with autosomal recessive limbgirdle muscular dystrophy, we identified a missense mutation in POGLUT1 (protein O-glucosyltransferase 1), an enzyme involved in Notch posttranslational modification and function. In vitro and in vivo experiments demonstrated that the mutation reduces Oglucosyltransferase activity on Notch and impairs muscle development. Muscles from patients revealed decreased Notch signaling, dramatic reduction in satellite cell pool and a muscle-specific adystroglycan hypoglycosylation not present in patients’ fibroblasts. Primary myoblasts from patients showed slow proliferation, facilitated differentiation, and a decreased pool of quiescent PAX7+ cells. A robust rescue of the myogenesis was demonstrated by increasing Notch signaling. None of these alterations were found in muscles from secondary dystroglycanopathy patients. These data suggest that a key pathomechanism for this novel form of muscular dystrophy is Notch-dependent loss of satellite cells.Junta de Andalucía PI-0017-201

charge transfer, strain, and electron-phonon coupling in graphene layers

Graphite intercalation compounds (GICs) are an interesting and highly studied field since 1970’s. It has gained renewed interest since the discovery of superconductivity at high temperature for CaCinline image and the rise of graphene. Intercalation is a technique used to introduce atoms or molecules into the structure of a host material. Intercalation of alkali metals in graphite has shown to be a controllable procedure recently used as a scalable technique for bulk production of graphene, and nano-ribbons by induced exfoliation of graphite. It also creates supra-molecular interactions between the host and the intercalant, inducing changes in the electronic, mechanical, and physical properties of the host. GICs are the mother system of intercalation also employed in fullerenes, carbon nanotubes, graphene, and carbon-composites. We will show how a combination of Raman and inline image calculations of the density and the electronic band structure in GICs can serve as a tool to elucidate the electronic structure, electron–phonon coupling, charge transfer, and lattice parameters of GICs and the graphene layers within. This knowledge of GICs is of high importance to understand superconductivity and to set the basis for applications with GICs, graphene and other nano-carbon based materials like nanocomposites in batteries and nanoelectronic devices

Innovación agrícola pro-pobre para la seguridad y soberanía alimentaria en la región andina: el caso IssAndes en Ecuador.

El proyecto "Innovación para la seguridad y la soberanía alimentaria en la región andina"- IssAndes, se inició en marzo del 2011 y culminó en marzo del 2015. El proyecto fue ejecutado en Bolivia, Ecuador, Perú y Colombia, con socios de agricultura, salud y educación en cada país. Fue coordinado por el Centro Internacional de la Papa (CIP) y financiado por la Unión Europea a través del Fondo Internacional de Desarrollo Agrícola (FIDA). El objetivo de IssAndes fue fortalecer la innovación para la seguridad alimentaria a diferentes niveles territoriales (local, nacional y regional) en la región andina, en respuesta a las necesidades de los grupos rurales vulnerables y así contribuir a la reducción de la desnutrición de niño/as menores de tres años mediante mejoras en la alimentación y nutrición de las familias. En el Ecuador, el proyecto se implementó en las provincias de Chimborazo, Tungurahua y Cotopaxi, en un total de 10 cantones y 17 parroquias, llegando a 44 comunidades con 1135 familias vinculadas al rubro papa. El proyecto tuvo un total de siete socios a nivel nacional (Instituto Nacional Autónomo de Investigaciones Agropecuarias - INIAP, Escuela Superior Politécnica de Chimborazo - ESPOCH, Visión Mundial, Estrategia Acción Nutrición - EAN, Oficina para Estudios del Agro - OfiAgro, Centro Latinoamericano para el Desarrollo Rural-RIMISP y la Fundación Minga para la Acción Rural y la Cooperación - MARCO) y dos socios a nivel regional (CIP y el Instituto de Investigación Nutricional - IIN). IssAndes estructuró sus acciones de investigación y desarrollo en cuatro componentes: i) Contribución de la papa a la nutrición y salud; ii) Mejoras en los sistemas de producción basados en papa; iii) Educación nutricional para el cambio de comportamiento; e iv) Incidencia pública y política