590 research outputs found

    Operation and Performance of Vehicular Ad-Hoc Routing Protocols in Realistic Environments

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    Abstract—Vehicle-to-vehicle and vehicle-to-infrastructure wireless communications are currently under development to improve traffic efficiency and safety. Routing protocols enabling multi-hop communications represent a major technology for information dissemination within vehicular ad-hoc networks. The high node’s mobility and propagation conditions experienced by vehicle-to-vehicle communications require a careful routing protocol design to ensure its successful operation and performance under realistic environments. To this aim, this paper analyses the impact and importance of adequately considering physical layer effects to correctly quantify a routing protocol’s performance, and understand its networking operation

    Metal-organic and supramolecular lead(II) networks assembled from isomeric nicotinoylhydrazone blocks : the effects of ligand geometry and counter-ion on topology and supramolecular assembly

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    A new series of six structurally diverse lead(II) coordination compounds was assembled from two isomeric nicotinoylhydrazones as neutral ligands and three Pb(II) salts with different monoanions (chloride, nitrate and thiocyanate) as starting materials. The products were isolated in good yields and were fully characterized, including by single-crystal Xray diffraction and theoretical methods. Within the six compounds, three feature 2D metal-organic networks, two are 1D coordination polymers, and another one comprises discrete 0D dimeric units. The structures of the latter low dimensional compounds are extendable into 2D supramolecular networks. The topology of the coordination or supramolecular networks is primarily dictated by the geometry of the nicotinoylhydrazone used as a main building block. In contrast, supramolecular interactions are greatly influenced by the choice of the anion in the starting lead(II) salt, which is demonstrated by Hirshfeld surface analysis. In fact, the topological analysis and classification of metal-organic or supramolecular underlying networks in the obtained compounds was performed, disclosing the hcb, 2C1, gek1, SP 1-periodic net (4,4)(0,2) and 3,4L83 topological types; the latter topology was docummented for three compounds, including both coordination and supramolecular networks. In two compounds containing thiocyanate moieties there are supramolecular contacts between thiocyanate anions and lead centres. These were shown by DFT calculations to be strong tetrel bonds (–15.3 and –16.7 kcal/mol) between the σ-hole of the lead atom and the π-system of the thiocyanate S–C bond

    Modelización de fenómenos físicos en aplicaciones de computación gráfica en tiempo real

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    Cuando se desarrollan aplicaciones de realidad virtual, uno de los principales desafíos es lograr realismo e inmersión a un costo computacional aceptable. Con las placas gráficas actuales es posible obtener imágenes muy cercanas a la realidad, aunque también se debe incluir comportamiento físico para lograr escenas que brinden una verdadera inmersión. Para cumplir este objetivo, se han desarrollado en los últimos años varios motores físicos implementados en forma de bibliotecas (ODE, NGD, TPE, BPL1) o en placas dedicadas a la simulación de modelos físicos (por ejemplo, el producto de nVIDIA® denominado PhysX); los cuales permiten agregar comportamiento físico a escenas tridimensionales. Es posible que los usuarios deseen realizar pruebas de rendimiento y/o precisión a cada motor físico para determinar cual de ellos se ajusta mejor a sus necesidades; o utilizar distintas funcionalidades de cada uno en una misma aplicación, pero ocurre que cada uno de estos motores necesita una configuración distinta de inicialización y muchas veces la funcionalidad implementada difiere entre uno y otro, haciendo que el código implementado sea obsoleto, requiriendo de un esfuerzo considerable para portar la aplicación a otro motor. Para solucionar dichos problemas, el presente trabajo se centra principalmente en crear una capa de abstracción o PAL (del inglés, Physics Abstraction Layer) que sea utilizada por un motor gráfico, la cual brinde una comunicación fluida con diversos motores físicos maximizando la reutilización de código y permita cambiar el uso entre ellos.Eje: Computación gráfica, Imágenes y VisualizaciónRed de Universidades con Carreras en Informática (RedUNCI

    Modelización de fenómenos físicos en aplicaciones de computación gráfica en tiempo real

    Get PDF
    Cuando se desarrollan aplicaciones de realidad virtual, uno de los principales desafíos es lograr realismo e inmersión a un costo computacional aceptable. Con las placas gráficas actuales es posible obtener imágenes muy cercanas a la realidad, aunque también se debe incluir comportamiento físico para lograr escenas que brinden una verdadera inmersión. Para cumplir este objetivo, se han desarrollado en los últimos años varios motores físicos implementados en forma de bibliotecas (ODE, NGD, TPE, BPL1) o en placas dedicadas a la simulación de modelos físicos (por ejemplo, el producto de nVIDIA® denominado PhysX); los cuales permiten agregar comportamiento físico a escenas tridimensionales. Es posible que los usuarios deseen realizar pruebas de rendimiento y/o precisión a cada motor físico para determinar cual de ellos se ajusta mejor a sus necesidades; o utilizar distintas funcionalidades de cada uno en una misma aplicación, pero ocurre que cada uno de estos motores necesita una configuración distinta de inicialización y muchas veces la funcionalidad implementada difiere entre uno y otro, haciendo que el código implementado sea obsoleto, requiriendo de un esfuerzo considerable para portar la aplicación a otro motor. Para solucionar dichos problemas, el presente trabajo se centra principalmente en crear una capa de abstracción o PAL (del inglés, Physics Abstraction Layer) que sea utilizada por un motor gráfico, la cual brinde una comunicación fluida con diversos motores físicos maximizando la reutilización de código y permita cambiar el uso entre ellos.Eje: Computación gráfica, Imágenes y VisualizaciónRed de Universidades con Carreras en Informática (RedUNCI

    Local transformations of the hippocampal cognitive map

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    Grid cells are neurons active in multiple fields arranged in a hexagonal lattice and are thought to represent the “universal metric for space.” However, they become nonhomogeneously distorted in polarized enclosures, which challenges this view. We found that local changes to the configuration of the enclosure induce individual grid fields to shift in a manner inversely related to their distance from the reconfigured boundary. The grid remained primarily anchored to the unchanged stable walls and showed a nonuniform rescaling. Shifts in simultaneously recorded colocalized grid fields were strongly correlated, which suggests that the readout of the animal’s position might still be intact. Similar field shifts were also observed in place and boundary cells—albeit of greater magnitude and more pronounced closer to the reconfigured boundary—which suggests that there is no simple one-to-one relationship between these three different cell types

    AMBRA1 is able to induce mitophagy via LC3 binding, regardless of PARKIN and p62/SQSTM1

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    Damaged mitochondria are eliminated by mitophagy, a selective form of autophagy whose dysfunction associates with neurodegenerative diseases. PINK1, PARKIN and p62/SQTMS1 have been shown to regulate mitophagy, leaving hitherto ill-defined the contribution by key players in 'general' autophagy. In basal conditions, a pool of AMBRA1 - an upstream autophagy regulator and a PARKIN interactor - is present at the mitochondria, where its pro-autophagic activity is inhibited by Bcl-2. Here we show that, upon mitophagy induction, AMBRA1 binds the autophagosome adapter LC3 through a LIR (LC3 interacting region) motif, this interaction being crucial for regulating both canonical PARKIN-dependent and -independent mitochondrial clearance. Moreover, forcing AMBRA1 localization to the outer mitochondrial membrane unleashes a massive PARKIN- and p62-independent but LC3-dependent mitophagy. These results highlight a novel role for AMBRA1 as a powerful mitophagy regulator, through both canonical or noncanonical pathways

    Simultaneous analysis of free amino acids and biogenic amines in honey and wine samples using in loop orthophthalaldeyde derivatization procedure

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    This work presents a RP-HPLC method for the simultaneous quantification of free amino acids and biogenic amines in liquid food matrices and the results of the application to honey and wine samples obtained from different production processes and geographic origins. The developed methodology is based on a pre-column derivatization with o-phthaldialdehyde carried out in the sample injection loop. The compounds were separated in a Nova-Pack RP-C18 column (150 mm × 3.9 mm, 4 μm) at 35 °C. The mobile phase used was a mixture of phase A: 10 mM sodium phosphate buffer (pH 7.3), methanol and tetrahydrofuran (91:8:1); and phase B: methanol and phosphate buffer (80:20), with a flow rate of 1.0 ml/min. Fluorescence detection was used at an excitation wavelength of 335 nm and an emission wavelength of 440 nm. The separation and quantification of 19 amino acids and 6 amines was carried out in a single run as their OPA/MCE derivatives elute within 80 min, ensuring a reproducible quantification. The method showed to be adequate for the purpose, with an average RSD of 2% for the different amino acids; detection limits varying between 0.71 mg/l (Asn) and 8.26 mg/l (Lys) and recovery rates between 63.0% (Cad) and 98.0% (Asp). The amino acids present at the highest concentration in honey and wine samples were phenylalanine and arginine, respectively. Only residual levels of biogenic amines were detected in the analysed samples

    Broad activation of the ubiquitin-proteasome system by Parkin is critical for mitophagy

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    Parkin, an E3 ubiquitin ligase implicated in Parkinson's disease, promotes degradation of dysfunctional mitochondria by autophagy. Using proteomic and cellular approaches, we show that upon translocation to mitochondria, Parkin activates the ubiquitin–proteasome system (UPS) for widespread degradation of outer membrane proteins. This is evidenced by an increase in K48-linked polyubiquitin on mitochondria, recruitment of the 26S proteasome and rapid degradation of multiple outer membrane proteins. The degradation of proteins by the UPS occurs independently of the autophagy pathway, and inhibition of the 26S proteasome completely abrogates Parkin-mediated mitophagy in HeLa, SH-SY5Y and mouse cells. Although the mitofusins Mfn1 and Mfn2 are rapid degradation targets of Parkin, we find that degradation of additional targets is essential for mitophagy. These results indicate that remodeling of the mitochondrial outer membrane proteome is important for mitophagy, and reveal a causal link between the UPS and autophagy, the major pathways for degradation of intracellular substrates

    Effects of environmental conditions on healthcare worker wellbeing and quality of care: A qualitative study in Niger

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    Environmental conditions (water, sanitation, hygiene, waste management, cleaning, energy, building design) are important for a safe and functional healthcare environment. Yet their full range of impacts are not well understood. In this study, we assessed the impact of environmental conditions on healthcare workers’ wellbeing and quality of care, using qualitative interviews with 81 healthcare workers at 26 small healthcare facilities in rural Niger. We asked participants to report successes and challenges with environmental conditions and their impacts on wellbeing (physical, social, mental, and economic) and quality of care. We found that all environmental conditions contributed to healthcare workers’ wellbeing and quality of care. The norm in facilities of our sample was poor environmental conditions, and thus participants primarily reported detrimental effects. We identified previously documented effects on physical health and safety from pathogen exposure, but also several novel effects on healthcare workers’ mental and economic wellbeing and on efficiency, timeliness, and patient centeredness of care. Key wellbeing impacts included pathogen exposure for healthcare workers, stress from unsafe and chaotic working environments, staff dissatisfaction and retention challenges, out-of-pocket spending to avoid stockouts, and uncompensated labor. Key quality of care impacts included pathogen exposure for patients, healthcare worker time dedicated to non-medical tasks like water fetching (i.e., reduced efficiency), breakdowns and spoilage of equipment and supplies, and patient satisfaction with cleanliness and privacy. Inefficiency due to time lost and damaged supplies and equipment likely have substantial economic value and warrant greater consideration in research and policy making. Impacts on staff retention and care efficiency also have implications for health systems. We recommend that future research and decision making for policy and practice incorporate more holistic impact measures beyond just healthcare acquired infections and reconsider the substantial contribution that environmental conditions make to the safety of healthcare facilities and strength of health systems

    Molecular profiling and feasibility using a comprehensive hybrid capture panel on a consecutive series of non-small-cell lung cancer patients from a single centre

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    Background: Targeted next-generation sequencing (NGS) is recommended to screen actionable genomic alterations (GAs) in patients with non-small-cell lung cancer (NSCLC). We determined the feasibility to detect actionable GAs using TruSight™ Oncology 500 (TSO500) in 200 consecutive patients with NSCLC. Materials and methods: DNA and RNA were sequenced on an Illumina® NextSeq 550 instrument and processed using the TSO500 Docker pipeline. Clinical actionability was defined within the molecular tumour board following European Society for Medical Oncology (ESMO) guidelines for oncogene-addicted NSCLC. Overall survival (OS) was estimated as per the presence of druggable GAs and treatment with targeted therapy. Results: Most patients were males (69.5%) and former or current smokers (86.5%). Median age was 64 years. The most common histological type and tumour stage were lung adenocarcinoma (81%) and stage IV (64%), respectively. Sequencing was feasible in most patients (93.5%) and actionable GAs were found in 26.5% of patients. A high concordance was observed between single-gene testing and TSO500 NGS panel. Patients harbouring druggable GAs and receiving targeted therapy achieved longer OS compared to patients without druggable GAs. Conversely, patients with druggable GAs not receiving targeted therapy had a trend toward shorter OS compared with driver-negative patients. Conclusions: Hybrid capture sequencing using TSO500 panel is feasible to analyse clinical samples from patients with NSCLC and is an efficient tool for screening actionable GAs
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