51 research outputs found
A comparative study of V2O5/AC and V2O5/Al2O3 catalysts for the selective catalytic reduction of NO by NH3
Overexpression of amyloid precursor protein increases copper content in HEK293 cells
Amyloid precursor protein (APP) is a transmembrane glycoprotein widely expressed in mammalian tissues and plays a central role in Alzheimer's disease. However, its physiological function remains elusive. Cu2+ binding and reduction activities have been described in the extracellular APP135-156 region, which might be relevant for cellular copper uptake and homeostasis. Here, we assessed Cu2+ reduction and 64Cu uptake in two human HEK293 cell lines overexpressing APP. Our results indicate that Cu2+ reduction increased and cells accumulated larger levels of copper, maintaining cell viability at supra-physiological levels of Cu2+ ions. Moreover, wild-type cells exposed to both Cu2+ ions and APP135-155 synthetic peptides increased copper reduction and uptake. Complementation of function studies in human APP751 transformed Fre1 defective Saccharomyces cerevisiae cells rescued low Cu2+ reductase activity and increased 64Cu uptake. We conclude that Cu2+ reduction activity of APP facilitates co
Examining the factorial validity of the entrepreneurial career motives scale: A five-nation comparison
Genome-wide identification of new Wnt/beta-catenin target genes in the human genome using CART method
Background: The importance of in silico predictions for understanding cellular processes is now widely accepted, and a variety of algorithms useful for studying different biological features have been designed. In particular, the prediction of cis regulatory modules in non-coding human genome regions represents a major challenge for understanding gene regulation in several diseases. Recently, studies of the Wnt signaling pathway revealed a connection with neurodegenerative diseases such as Alzheimer's. In this article, we construct a classification tool that uses the transcription factor binding site motifs composition of some gene promoters to identify new Wnt/beta-catenin pathway target genes potentially involved in brain diseases
Direct synthesis of graphitic carbon nanostructures from saccharides and their use as electrocatalytic supports
An easy method is described for fabricating graphitic carbon nanostructures (GCNs) from a variety of saccharides; i.e., a monosaccharide (glucose), a disaccharide (sucrose) and a polysaccharide (starch). The synthesis scheme consists of: (a) impregnation of saccharide with Ni or Fe nitrates, (b) heat treatment under inert atmosphere (N2) up to 900°C or 1000°C and (c) oxidation in liquid phase to selectively recover the graphitic carbon. This procedure leads to GCNs with a variety of morphologies: nanopipes nanocoils and nanocapsules. Such GCNs have a high crystallinity, as shown by TEM/SAED, XRD and Raman analysis. The GCNs were used as supports for platinum nanoparticles, which were well dispersed (Mean Pt size ~2–3 nm). Electrocatalysts thus prepared have electrocatalytic surface areas in the 70–95 m2 g−1 Pt range and exhibit high catalytic activities towards methanol electrooxidation.Financial support for this research work provided by the Spanish MCyT (MAT2005-00262, MAT2004-01479 and FEDER)
Preparation of Monolithic Carbon Aerogels and Investigation of Their Pore Interconnectivity by a Nanocasting Pathway
Applying plant facilitation to forest restoration in Mediterranean ecosystems: a meta-analysis of the use of shrubs as nurse plants
11 pages, 4 figures, 1 table, 75 references. We thank the ConsejerÃa de Medio Ambiente, Junta de
AndalucÃa, and the Direction of the National Park of Sierra
Nevada for permission to field work, constant support and
facilities. We are also especially grateful to Empresa de Transformación Agraria S.A. (TRAGSA) for carrying out the experimental
reforestation. We thank Sergio de Haro and several
students for field assistance. David Nesbitt looked over the
English version of the manuscript.After a millenarian history of overexploitation, most forests in the Mediterranean
Basin have disappeared, leaving many degraded landscapes that have been recolonized
by early successional shrub-dominated communities. Common reforestation techniques
treat these shrubs as competitors against newly planted tree seedlings; thus shrubs
are cleared before tree plantation. However, empirical studies and theory governing plant–
plant interactions suggest that, in stress-prone Mediterranean environments, shrubs can
have a net positive effect on recruitment of other species. Between 1997 and 2001, we
carried out experimental reforestations in the Sierra Nevada Protected Area (southeast
Spain) with the aim of comparing the survival and growth of seedlings planted in open
areas (the current reforestation technique) with seedlings planted under the canopy of
preexisting shrub species. Over 18 000 seedlings of 11 woody species were planted under
16 different nurse shrubs throughout a broad geographical area. We sought to explore
variation in the sign and magnitude of interactions along spatial gradients defined by altitude
and aspect. In the present work, we report the results of a meta-analysis conducted with
seedling survival and growth data for the first summer following planting, the most critical
period for reforestation success in Mediterranean areas. The facilitative effect was consistent
in all environmental situations explored (grand mean effect size d1 5 0.89 for survival and
0.27 for growth). However, there were differences in the magnitude of the interaction,
depending on the seedling species planted as well as the nurse shrub species involved.
Additionally, nurse shrubs had a stronger facilitative effect on seedling survival and growth
at low altitudes and sunny, drier slopes than at high altitudes or shady, wetter slopes.
Facilitation in the dry years proved higher than in the one wet year. Our results show that
pioneer shrubs facilitate the establishment of woody, late-successional Mediterranean species
and thus can positively affect reforestation success in many different ecological settings.This study was supported
by a PFPU-MECD grant to L. G. and PFPI-MCYT to E. B.
and projects FEDER 1FD97-0743-CO3-02 and REN 2001-
4552-E from MCYT.Peer reviewe
Winter temperature predicts prolonged diapause in pine processionary moth species across their geographic range
Combined influence of alkaline earth metals and CO2 on performance of hierarchical zeolite Beta in n-hexane isomerization
- …