288 research outputs found
Synthesis of In_2S_3 and In_6S_7 microcolumns and nanowires by a vapor-solid method
Indium sulfide (In_2S_3) is a promising candidate for the replacement of CdS buffer layers in solar cell devices, while hexaindium heptasulfide (In_6S_7) presents interesting properties for its use as absorber material. In this work the fabrication of In_2S_3 microcolumns as well as novel In_6S_7 nanowires with diameters of about 70-120nm is reported. The structures are grown following a thermal evaporation-deposition method at temperatures between 900 and 1000º C. Control of the phase and morphology of the structures is achieved through both the evaporation and deposition temperatures, which can be tuned separately. Energy dispersive spectroscopy shows no traces of residual oxygen, while X-ray photoelectron spectroscopy indicates the presence of small amounts of oxygen incorporated at the surface of the structures. The In_6S_7 nanowires are found to be degenerated n-type semiconductors, with the Fermi level above the conduction band minimum. The origin of this n-type degeneracy is discussed in terms of S vacancies
Tubular micro- and nanostructures of TCO materials grown by a vapor-solid method
Microtubes and rods with nanopipes of transparent conductive oxides (TCO), such as SnO_2, TiO_2, ZnO and In_2O_3, have been fabricated following a vapor-solid method which avoids the use of catalyst or templates. The morphology of the as-grown tubular structures varies as a function of the precursor powder and the parameters employed during the thermal treatments carried out under a controlled argon flow. These materials have been also doped with different elements of technological interest (Cr, Er, Li, Zn, Sn). Energy Dispersive X-ray Spectroscopy (EDS) measurements show that the concentration of the dopants achieved by the vapor-solid method ranges from 0.5 to _3 at.%. Luminescence of the tubes has been analyzed, with special attention paid to the influence of the dopants on their optical properties. In this work, we summarize and discuss some of the processes involved not only in the anisotropic growth of these hollow micro and nanostructures, but also in their doping
An unprecedented use for glycerol: chemoselective reducing agent for sulfoxides
A new application for glycerol that expands its possibilities beyond a green solvent and a precursor of
value-added products has been demonstrated. Simple, easily available, and environmentally friendly dioxomolybdenum(
VI) complexes are highly efficient catalysts for the chemoselective sulfoxide deoxygenation
with this biomass-derived chemical feedstock. Both refined glycerol and crude glycerin can be used, thus
expanding the potential application of this reaction. Subsequent transformation of glycerol during this
reductive process has also been investigatedMinisterio de Ciencia e Innovacion (MICINN), FEDER (CTQ2010-15358 and CTQ2009-09949/BQU), Junta de Castilla y Leon (BU021A09 and GR-172), MICINN ("Juan de la Cierva" and "Ramon y Cajal" contracts for P.G.-G. and M.A.F.-R.
Grain selective Cu oxidation and anomalous shift of graphene 2D Raman peak in the graphene-Cu system
Understanding the interaction between graphene and its supporting substrate is of paramount importance for the development of graphene based applications. In this work the interplay of the technologically relevant graphene-Cu system is investigated in detail as a function of substrate grain orientation in Cu polycrystalline foils. While (100) and (111) Cu grains show the well-known graphene-enhanced oxidation, (110) grains present a superior oxidation resistance compared to uncovered Cu and an anomalous shift of its graphene 2D Raman band which cannot be explained by the known effects of strain and doping. These results are interpreted in terms of a weak graphene-Cu coupling at the (110) grains, and show that graphene can actually be used as anticorrosion coating, contrary to previously reported. The anomalous shift is suggested to be the result of an enhanced outer Raman scattering process which surpasses the usually dominant inner process. Since Raman spectroscopy is widely used as first and main characterization tool of graphene, the existence of an anomalous shift on its 2D band not only challenges the current theory of Raman scattering in graphene, but also has profound implications from an experimental point of view
Motor neuron preservation and decrease of in vivo TDP-43 phosphorylation by protein CK-1δ kinase inhibitor treatment
athogenesis of amyotrophic lateral sclerosis (ALS), a devastating disease where no treatment exists, involves the compartmentalization of the nuclear protein TDP-43 (TAR DNA-binding protein 43) in the cytoplasm which is promoted by its aberrant phosphorylation and others posttranslational modifications. Recently, it was reported that CK-1δ (protein casein kinase-1δ) is able to phosphorylate TDP-43. Here, the preclinical efficacy of a benzothiazole-based CK-1δ inhibitor IGS-2.7, both in a TDP-43 (A315T) transgenic mouse and in a human cell-based model of ALS, is shown. Treatment with IGS-2.7 produces a significant preservation of motor neurons in the anterior horn at lumbar level, a decrease in both astroglial and microglial reactivity in this area, and in TDP-43 phosphorylation in spinal cord samples. Furthermore, the recovery of TDP-43 homeostasis (phosphorylation and localization) in a human-based cell model from ALS patients after treatment with IGS-2.7 is also reported. Moreover, we have shown a trend to increase in CK-1δ mRNA in spinal cord and significantly in frontal cortex of sALS cases. All these data show for the first time the in vivo modulation of TDP-43 toxicity by CK-1δ inhibition with IGS-2.7, which may explain the benefits in the preservation of spinal motor neurons and point to the relevance of CK-1δ inhibitors in a future disease-modifying treatment for ALS
Libro de actas de la II Conferencia Internacional de Investigación en Educación 2021: Retos de la educación post-pandemia
La International Conference of Research in Education (IRED) es un evento celebrado de forma bienal
auspiciado por la Red de Institutos de Investigación en Educación (RIIE). La primera edición se celebró en
noviembre de 2019 en la Universidad de Barcelona, y esta segunda edición de la Conferencia Internacional
IRED tiene lugar en el Instituto Universitario de Ciencias de la Educación (IUCE) de la Universidad de Salamanca
del 3 al 5 de noviembre de 2021, en un formato híbrido (presencial y online) debido a la incertidumbre y la
situación derivada de la pandemia provocada por la COVID-19.
Precisamente, la influencia de la COVID-19 en la investigación educativa, con el objetivo puesto en la
situación en la que quedará la educación una vez que la pandemia esté superada, es el tema central de esta
edición, la cual busca conocer todos aquellos retos que la educación digital ha de afrontar tras el nuevo
escenario que la pandemia ha abierto.
Los temas principales que esta edición de IRED21 ha abordado, y que se presentan en las actas que a
continuación dan comienzo, siguen como principales temáticas la docencia híbrida y las experiencias de
educación a distancia, las TIC en educación y las innovaciones docentes, la orientación educativa y la formación
del profesorado y, finalmente, la investigación educativa y los proyectos de investigación. Todo ello con el
objetivo de analizar, comprender y avanzar en el nuevo escenario educativo que se abre en la educación digital
tras la pandemia
Influence of cation substitution on the complex structure and luminescent properties of the Zn_kIn_2O_(k+3) system
The effect of In^(3+) substitution by Ga^(3+) or Al^(3+) on the structure and luminescent properties of Zn_7In_(2-x)M_xO_10 (M = Ga or Al; 0 <= x <= 1) oxides has been investigated by means of high spatial resolution X-ray spectroscopy and high-angle annular dark-field images, combined with magic angle spinning nuclear magnetic resonance spectroscopy. Local structural variations have been identified for the Al- and Ga-doped samples through the analysis of atomically resolved chemical maps and the identification of their structural environment within the wurtzite lattice. In3+ is distributed in a zig-zag modulation, while Al^(3+) and Ga^(3+) are located in a flat distribution at the center of the wurtzite block. Density functional theory calculations provide unambiguous evidence for the preferential flat location of Ga^(3+) and Al^(3+) associated with the different strains introduced in the structure as a result of their ionic radii. The characterization of the photoluminescence response reveals the appearance of new radiative recombination pathways for the doped materials because of the presence of new defect levels in the band gap of the Zn_7In_2O_10 structure
Ingeniería Geológica en Terrenos Volcánicos. Métodos, Técnicas y Experiencias en las Islas Canarias
La presente obra es un compendio de conceptos, metodologías y técnicas útiles
para acometer proyectos y obras en terrenos volcánicos desde el punto de vista de la ingeniería geológica y la geotecnia.
El libro se presenta en tres partes diferenciadas. La primera es conceptual y
metodológica, con capítulos que tratan sobre la clasificación de las rocas volcánicas con fines geotécnicos, la caracterización geomecánica, los problemas geotécnicos y constructivos asociados a los distintos materiales, y una guía metodológica para la redacción de informes geotécnicos para la edificación. La segunda parte aborda las aplicaciones a obras de ingeniería, incluyendo deslizamientos, obras subterráneas,infraestructuras marítimas y obras públicas. La tercera parte recoge capítulos dedicados a describir distintos casos prácticos de obras y proyectos en los que la problemática geotécnica en terrenos volcánicos ha tenido un papel relevante.
Los capítulos han sido elaborados por técnicos y científicos de reconocido prestigio en el campo de la ingeniería geológica en terrenos volcánicos, que han plasmado en ellos sus conocimientos y experiencias en la materia.Los editores y autores de parte de los capítulos del libro, los Doctores Luis E. Hernández Gutiérrez (Geólogo) y Juan Carlos Santamarta Cerezal (Ingeniero de Montes, Civil y Minas), son los responsables del grupo de investigación INGENIA (Ingeniería Geológica, Innovación y Aguas).
Su actividad investigadora comprende más de 200 publicaciones en el área de la
ingeniería geológica, la geotecnia, medio ambiente y el aprovechamiento del agua
en islas y terrenos volcánicos. En relación a la docencia han impartido y dirigido
más de 90 seminarios y cursos de especialización a nivel nacional e internacional,
incluyendo la organización de 4 congresos internacionales. Fueron premiados por
la Universidad de La Laguna en los años 2012, 2013 y 2014 por su calidad docente
e innovación universitaria, y son pioneros en los laboratorios virtuales para la
enseñanza de la ingeniería. Participan activamente como profesores colaboradores
e investigadores en varias universidades e instituciones españolas e internacionales.
Todas sus publicaciones están disponibles en internet, con libre acceso.
Ingeniería geológica en terrenos volcánicos, es una obra de gran interés para,
consultores, técnicos de administraciones públicas, proyectistas y demás
profesionales implicados en obras y proyectos de infraestructuras en terrenos
volcánicos; también es útil para académicos y estudiantes de ingeniería o ciencias
geológicas que quieran investigar o iniciarse en las singularidades que presentan
los materiales volcánicos en la edificación o en la ingeniería civil y minera
Search for same-sign top-quark pair production at √s=7 TeV and limits on flavour changing neutral currents in the top sector.
An inclusive search for same-sign top-quark pair production in pp collisions at √s = 7TeV is performed using a data sample recorded with the CMS detector in 2010, corresponding to an integrated luminosity of 35 pb-1. This analysis is motivated by recent studies of pp ̅ →tt ̅ reporting mass-dependent forward-backward asymmetries larger than expected from the standard model. These asymmetries could be due to Flavor Changing Neutral Currents (FCNC) in the top sector induced by t-channel exchange of a massive neutral vector boson (Z’). Models with such a Z' also predict enhancement of same-sign top-pair production in pp or pp ̅ collisions. Limits are set as a function of the Z’ mass and its couplings to u and t quarks. These limits disfavour the FCNC interpretation of the Tevatron results.We thank Johan Alwall, Ed Berger, Qing-Hong Cao, Chuan-Ren Chen, Chong-Sheng Li and Hao Zhang for discussions and help in implementing the Z0 model in Mad- Graph/MadEvent. We wish to congratulate our colleagues in the CERN accelerator departments for the excellent performance of the LHC machine. We thank the technical and administrative sta_ at CERN and other CMS institutes, and acknowledge support from: FMSR (Austria); FNRS and FWO (Belgium); CNPq, CAPES, FAPERJ, and FAPESP (Brazil); MES (Bulgaria); CERN; CAS, MoST, and NSFC (China); COLCIENCIAS (Colombia); MSES (Croatia); RPF (Cyprus); Academy of Sciences and NICPB (Estonia); Academy of Finland, ME, and HIP (Finland); CEA and CNRS/IN2P3 (France); BMBF, DFG, and HGF (Germany); GSRT (Greece); OTKA and NKTH (Hungary); DAE and DST (India); IPM (Iran); SFI (Ireland); INFN (Italy); NRF and WCU (Korea); LAS (Lithuania); CINVESTAV, CONACYT, SEP, and UASLP-FAI (Mexico); PAEC (Pakistan); SCSR (Poland); FCT (Portugal); JINR (Armenia, Belarus, Georgia, Ukraine, Uzbekistan); MST and MAE (Russia); MSTD (Serbia); MICINN and CPAN (Spain); Swiss Funding Agencies (Switzerland); NSC (Taipei); TUBITAK and TAEK (Turkey); STFC (United Kingdom); DOE and NSF (USA)
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