1,345 research outputs found

    Programming DNA-Based Systems through Effective Molarity Enforced by Biomolecular Confinement

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    The fundamental concept of effective molarity is observed in a variety of biological processes, such as protein compartmentalization within organelles, membrane localization and signaling paths. To control molecular encountering and promote effective interactions, nature places biomolecules in specific sites inside the cell in order to generate a high, localized concentration different from the bulk concentration. Inspired by this mechanism, scientists have artificially recreated in the lab the same strategy to actuate and control artificial DNA-based functional systems. Here, it is discussed how harnessing effective molarity has led to the development of a number of proximity-induced strategies, with applications ranging from DNA-templated organic chemistry and catalysis, to biosensing and protein-supported DNA assembly

    Spectral optical monitoring of the double peaked emission line AGN Arp 102B: II. Variability of the broad line properties

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    We investigate a long-term (26 years, from 1987 to 2013) variability in the broad spectral line properties of the radio galaxy Arp 102B, an active galaxy with broad double-peaked emission lines. We use observations presented in Paper I (Shapovalova et al. 2013) in the period from 1987 to 2011, and a new set of observations performed in 2012--2013. To explore the BLR geometry, and clarify some contradictions about the nature of the BLR in Arp 102B we explore variations in the Hα\alpha and Hβ\beta line parameters during the monitored period. We fit the broad lines with three broad Gaussian functions finding the positions and intensities of the blue and red peaks in Hα\alpha and Hβ\beta. Additionally we fit averaged line profiles with the disc model. We find that the broad line profiles are double-peaked and have not been changed significantly in shapes, beside an additional small peak that, from time to time can be seen in the blue part of the Hα\alpha line. The positions of the blue and red peaks { have not changed significantly during the monitored period. The Hβ\beta line is broader than Hα\alpha line in the monitored period. The disc model is able to reproduce the Hβ\beta and Hα\alpha broad line profiles, however, observed variability in the line parameters are not in a good agreement with the emission disc hypothesis. It seems that the BLR of Arp 102B has a disc-like geometry, but the role of an outflow can also play an important role in observed variation of the broad line properties.Comment: 17 pages, Accepted for publication in A&

    Learning Based on Problems (ABP), Impact of RAEE: A Case Study

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    Using a case of research as a methodological tool, applied in the research lab with students of the ninth semester of the academic program of chemical engineering (IQ) of the Faculty of chemical sciences and engineering (FCQeI) of the Autonomous University of the State of Morelos (UAEM), analyzed competition to students include scientific concepts acquired, where education is a human process more than verify that cognitive skills according to the approach [1], are developed during the resolution of the case. The results showed that students managed to explain the concepts involved, reflected on his own work and realized what had to be improved. For that, students employed higher order cognitive skills, such as explain, investigate, conclude, argue, make decisions and cognitive skills of low order, such as describing, enunciating, memorize and reproduce

    Who moved my protein? Mechanisms of Epileptogenesis due to Mutations of Voltage-Gated Sodium Channel SCN1B.

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    Voltage-gated sodium channels (VGSCs) play a role in the generation of action potentials in excitable cells, including neurons. VGSCs contain one pore-forming α subunit, one non-covalently linked (β1 or β3) and one covalently linked β subunit (β2 or β4). VGSC β subunits participate in channel modulation and cell adhesion. SCN1B, the gene encoding β1, is expressed as two splice variants: β1 and β1B. Both splice variants share a signal peptide and extracellular immunoglobulin loop domain in their N-termini. In contrast, the C-termini of each protein have little to no conservation. β1 contains a transmembrane domain, while β1B does not. Our results show that β1B is a secreted cell adhesion molecule that promotes neurite outgrowth. β1B is the predominantly expressed SCN1B splice variant during fetal brain development. We predict that β1B plays important roles in the establishment of neuronal excitability and disruptions in its expression may lead to brain disease. Heterozygous mutations in SCN1B have been reported as a cause of mild to moderate forms of Genetic Epilepsy with Febrile Seizures Plus (GEFS+). Here we report the first case of the epileptic encephalopathy Dravet Syndrome, characterized at the severe end of the GEFS+ spectrum, associated with a homozygous mutation of SCN1B. Our work demonstrates that the protein generated by this mutation, p.R125C, is trafficking deficient, resulting in the functional null phenotype in homozygous probands. Consistent with this, we propose that Scn1b null mice are an animal model of Dravet Syndrome. To date, all reported SCN1B mutations associated with epilepsy are located in the region common to β1 and β1B. Here we describe the first SCN1B mutation in the region exclusive to β1B associated with primary generalized epilepsy in heterozygous state. The protein produced by the mutation, p.G257R, is trafficking deficient, similar to p.R125C. Not surprisingly, its ability to promote neurite outgrowth in vitro is abolished. These results support our hypothesis that β1B plays a role in axon guidance during fetal development of the CNS. Taken together, this thesis work makes significant and novel contributions to our understanding of the role of VGSC SCN1B in normal brain development and neurological disease.Ph.D.NeuroscienceUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/78844/1/gapatino_1.pd

    A Common Software Configuration Management System for CERN SPS and LEP Accelerators and Technical Services

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    Software configuration management activities are crucial to assure the integrity of current operational and the quality of new software either being developed at CERN or outsourced. The functionality of the present management system became insufficient with large maintenance overheads. In order to improve our situation, a new software configuration management system has been set up. It is based on Razor, a commercial tool, which supports the management of file versions and operational software releases, along with integrated problem reporting capabilities. In addition to the basic tool functionality, automated procedures were custom made, for the installation and distribution of operational software. Policies were developed and applied over the software development life cycle to provide visibility and control. The system ensures that, at all times, the status and location of all deliverable versions are known, the state of shared objects is carefully controlled and unauthorised changes prevented. It provides a managed environment for software development, in various domains of the SPS and LEP CERN accelerators, and the technical services, automating code and lifecycle management. This paper outlines the reasons for selecting the chosen tool, the implementation of the system, the problems solved and the final goals achieved

    Assessment of Endocrine and Gonadal Condition of Male Largemouth Bass from Lake Mead, Nevada

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    Las Vegas Bay (LVB) of Lake Mead receives combined flows of tertiary treated wastewater effluent, urban runoff, and groundwater from the Las Vegas metropolitan area. This study examined the potential for endocrine disrupting effects of these anthropogenic inputs on male largemouth bass (Micropterus salmoides). Adult male bass were collected at two sites within Lake Mead: Overton Arm (OA, reference site), and Las Vegas Bay (LVB). Post-spawn fish were collected in July 2007 (n = 6-10 per site) and pre-spawn fish in March 2008 (n = 13 per site). Post-spawn fish were characterized by regressed testes whereas pre-spawn bass had full-grown gonads. Mean fish lengths and weights did not vary between sites or sampling times. Pre-spawn LVB males had lower plasma 11-ketotestosterone (KT), higher estradiol-17β (E2), higher E2/KT ratio, higher hepatosomatic index (ratio of liver to body weight), higher hematocrit values, and higher condition factor compared to OA males. However, no significant differences were evident in the gonadosomatic index (ratio of testes to body weight) of either pre-or post-spawn males from the two sites. In post-spawn males, no significant site-associated differences were detected for any of the parameters measured. Overall, these results suggest the existence of site-specific environmental influences on several indices of endocrine condition and health of pre-spawn male largemouth bass in Lake Mead, and are generally consistent with outcomes from previous studies that suggested the occurrence of altered endocrine and reproductive condition in male common carp from LVB

    Volcanism and geochemistry in Central America: Progress and problems

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    Quantifying slumness with remote sensing data

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    The presence of slums in a city is an indicator of poverty and its proper delimitation is a matter of interest for researchers and policy makers. Socio-economic data from surveys and censuses are the primary source of information to identify and quantify slumness within a city or a town. One problem of using survey data for quantifying slumness is that this type of data is usually collected every ten years and is an expensive and time consuming process. Based on the premise that the physical appearance of an urban settlement is a reflection of the society that created it and on the assumption that people living in urban areas with similar physical housing conditions will have similar social and demographic characteristics (Jain, 2008; Taubenb¨ock et al., 2009b); this paper uses data from Medellin City, Colombia, to estimate slum index using solely remote sensing data from an orthorectified, pan-sharpened, natural color Quickbird scene. For Medellin city, the percentage of clay roofs cover and the mean swimming pool density at the analytical region level can explain up to 59% of the variability in the slum index. Structure and texture measures are useful to characterize the differences in the homogeneity of the spatial pattern of the urban layout and they improve the explanatory power of the statistical models when taken into account. When no other information is used, they can explain up to 30% of the variability of the slum index. The results of this research are encouraging and many researchers, urban planners and policy makers could benefit from this rapid and low cost approach to characterize the intra-urban variations of slumness in cities with sparse data or no data at all
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