14,621 research outputs found
Chromatin remodeling and neuronal function: exciting links
Regulation of gene expression occurs at different levels, from DNA to protein, and through various mechanisms. One of them is modification of the chromatin structure, which is involved in the definition of transcriptional active and inactive regions of the chromosomes. These phenomena are associated with reversible chemical modifications of the genetic material rather than with variability within the DNA sequences inherited by the individual and are therefore called 'epigenetic' modifications. Ablation of the molecular players responsible for epigenetic modifications often gives rise to neurological and behavioral phenotypes in humans and in mouse models, suggesting a relevant function for chromatin remodeling in central nervous system function, particularly in the adaptive response of the brain to stimuli. We will discuss several human disorders that are due to altered epigenetic mechanisms, with special focus on Rett syndrome.Mónica Santos and Paula A. Coelho are supported by Fundação
para a Ciência e Tecnologia (FCT, Portugal) with the PhD fellowship SFRH/BD/9111/2002 and SFRH/BPD/20360/2004, respectively. Research in Rett syndrome is supported by the FSE/
FEDER and the FCT, grant POCTI 41416/200
<i>Schistosoma mansoni</i> cercariae experience influx of macromolecules during skin penetration
We have observed that when cercariae penetrate the skin of mice, there is influx into their tissues of Lucifer Yellow and certain labelled molecules of up to 20 kDa molecular weight. This observation was made using a variety of fluorescent membrane-impermeant compounds injected into the skin before the application of cercariae. This unexpected phenomenon was investigated further by transforming cercariae in vitro in the presence of the membrane-impermeant compounds and examining the distribution by microscopy. In schistosomula derived from this procedure, the nephridiopore and surface membrane were labelled while the pre- and post-acetabular glands were not labelled. The region associated with the oesophagus within the pharyngeal muscle clearly contained the fluorescent molecules, as did the region adjacent to the excretory tubules and the germinal mass. We used cercariae stained with carmine to aid identification of regions labelled with Lucifer Yellow. Although the mechanism of this influx is unclear, the observation is significant. From it, we can suggest an hypothesis that, during skin penetration, exposure of internal tissues of the parasite to external macromolecules represents a novel host-parasite interfac
Precise water leak detection using machine learning and real-time sensor data
Water is a crucial natural resource, and it is widely mishandled, with an estimated one third of world water utilities having loss of water of around 40% due to leakage. This paper presents a proposal for a system based on a wireless sensor network designed to monitor water distribution systems, such as irrigation systems, which, with the help of an autonomous learning algorithm, allows for precise location of water leaks. The complete system architecture is detailed, including hardware, communication, and data analysis. A study to discover the best machine learning algorithm between random forest, decision trees, neural networks, and Support Vector Machine (SVM) to fit leak detection is presented, including the methodology, training, and validation as well as the obtained results. Finally, the developed system is validated in a real-case implementation that shows that it is able to detect leaks with a 75% accuracy.info:eu-repo/semantics/publishedVersio
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