Very high-energy γ-ray observations of the Crab nebula and other potential sources with the GRAAL experiment

The “γ-ray astronomy at Almeria” (GRAAL) experiment uses 63 heliostat-mirrors with a total mirror area of ≈2500 m2 from the CESA-1 field at the “Plataforma Solar de Almeria” to collect Cherenkov light from air showers. The detector is located in a central solar tower and detects photon-induced showers with an energy threshold of 250±110 GeV and an asymptotic effective detection area of about 15 000 m2. A comparison between the results of detailed Monte-Carlo simulations and data is presented. Data sets taken in the period September 1999–September 2000 in the direction of the Crab pulsar, the active galaxy 3C 454.3, the unidentified γ-ray source 3EG J1835+59 and a “pseudosource” were analyzed for high energy γ-ray emission. Evidence for a γ-ray flux from the Crab pulsar with an integral flux of 2.2±0.4 above threshold and a significance of 4.5σ in a total measuring time of 7 h and 10 min on source was found. No evidence for emission from the other sources was found. Some difficulties with the use of heliostat fields for γ-ray astronomy are pointed out. In particular the effect of field-of-view restricted to the central part of a detected air shower on the lateral distribution and timing properties of Cherenkov light are discussed. Upon restriction the spread of the timing front of proton-induced showers sharply decreases and the reconstructed direction becomes biased towards the pointing direction. This is shown to make efficient γ-hadron separation difficult

Self-assembling peptides as an emerging platform for the treatment metabolic syndrome

open access articleMetabolic syndrome comprises a cluster of comorbidities that represent a major risk of developing chronic diseases, such as type II diabetes, cardiovascular diseases, and stroke. Alarmingly, metabolic syndrome reaches epidemic proportions worldwide. Today, lifestyle changes and multiple drug-based therapies represent the gold standard to address metabolic syndrome. However, such approaches face two major limitations: complicated drug therapeutic regimes, which in most cases could lead to patient incompliance, and limited drug efficacy. This has encouraged scientists to search for novel routes to deal with metabolic syndrome and related diseases. Within such approaches, self-assembled peptide formulations have emerged as a promising alternative for treating metabolic syndrome. In particular, self-assembled peptide hydrogels, either as acellular or cell-load three-dimensional scaffoldings have reached significant relevance in the biomedical field to prevent and restore euglycemia, as well as for controlling cardiovascular diseases and obesity. This has been possible thanks to the physicochemical tunability of peptides, which are developed from a chemical toolbox of versatile amino acids enabling flexibility of designing a wide range of self-assembled/co-assembled nanostructures forming biocompatible viscoelastic hydrogels. Peptide hydrogels can be combined with several biological entities, such as extracellular matrix proteins, drugs or cells, forming functional biologics with therapeutic ability for treatment of metabolic syndrome-comorbidities. Additionally, self-assembly peptides combine safety, tolerability, and effectivity attributes; by this presenting a promising platform for the development of novel pharmaceuticals capable of addressing unmet therapeutic needs for diabetes, cardiovascular disorders and obesity. In this review, recent advances in developing self-assembly peptide nanostructures tailored for improving treatment of metabolic syndrome and related diseases will be discussed from basic research to preclinical research studies. Challenges facing the development of approved medicinal products based on self-assembling peptide nanomaterials will be discussed in light of regulatory requirement for clinical authorization

La investigación prehistórica en Extremadura: los últimos 25 años

Se pretende revisar la investigación prehistórica desarrollada en y sobre el territorio extremeño a lo largo del último cuarto de siglo (1985-2010); un tiempo caracterizado esencialmente por constituir una fase de estudios continuados –realmente la primera en la historia de la investigación, favorecida por la creación de la Comunidad Autónoma de Extremadura–, con una producción científica sostenida y, en gran medida, realizada desde la propia región. Partiendo de una valoración general sobre el incremento de los estudios prehistóricos, pasaremos revista a los principales avances experimentados en los diversos horizontes y/o problemáticas de la prehistoria remota, la prehistoria reciente y la protohistoria; para concluir con un epígrafe sobre las principales líneas específicamente abordadas desde el Área de Prehistoria de la Universidad de Extremadura.It is claimed to revise the prehistoric research in and on land of Extremadura during last quarter of century (1985-2010); a time characterized essentially by constitute a stage of continued studies –really, the first in the history of the investigation, it is favoured by the creation of Comunidad Autónoma of Extremadura– with a scientific production that it is supported and also achieved in this region. Beginning with a general valoration about the increase of prehistoric studies, we analize the principal and experienced advances in the different horizons and/ or troubles of the remote prehistoric, the recent prehistoric and the protohistoric; we finish with a epigraph about principal lines specially undertaked from Area of Prehistory of Extremadura University.peerReviewe