2,586 research outputs found
Adsorption of Sugars on Al- and Ga-doped Boron Nitride Surfaces: A Computational Study
Molecular adsorption on surfaces is a key element for many applications,
including sensing and catalysis. Non-invasive sugar sensing has been an active
area of research due to its importance to diabetes care. The adsorption of
sugars on a template surface study is at the heart of matter. Here, we study
doped hexagonal boron nitride sheets (-BNNs) as adsorbing and sensing
template for glucose and glucosamine. Using first principles calculations, we
find that the adsorption of glucose and glucosamine on -BNNs is
significantly enhanced by the substitutional doping of the sheet with Al and
Ga. Including long range van der Waals corrections gives adsorption energies of
about 2 eV. In addition to the charge transfer occurring between glucose and
the Al/Ga-doped BN sheets, the adsorption alters the size of the band gap,
allowing for optical detection of adsorption. We also find that Al-doped boron
nitride sheet is better than Ga-nitride sheet to enhance the adsorption energy
of glucose and glucosamine. The results of our work can be potentially utilized
when designing support templates for glucose and glucosamine
Propuesta de un modelo gerencial aplicado a proyectos de Infraestructura vial adjudicados por el Instituto de Desarrollo Urbano (IDU), a partir de la metodología PMBOK
Trabajo de investigaciónBasados en la experiencia en la ejecución de contratos de mantenimiento de la infraestructura Vial del Instituto de Desarrollo Urbano (IDU) en la ciudad de Bogotá y en las constantes problemáticas que surgen en las etapas constructivas de los proyectos de mantenimiento. Es necesario buscar alternativas desde el punto de vista de dirección de proyectos para mitigar las circunstancias que no permiten cumplir las expectativas tanto técnicas como económicas de estos proyectos. Enfocados en una correcta planeación, ejecución y control, con el fin de suplir cada
una de las necesidades del IDU y de las diferentes tipologías de contratos de mantenimiento ofrecidas por dicha entidad, es por eso que surge la necesidad de generar una herramienta que basada en la experiencia en situaciones atípicas presentadas en la ejecución de proyectos de mantenimiento y en la metodología PMBOK logre mostrar un norte para enfrentarse de una manera coherente a la gerencia de obra en uno de estos contratos.Introducción
1 Generalidades
2 Marcos de referencia
3 Metodología
4 Productos a entregar
5 Descripción de resultados esperados e impacto
6 Desarrollo del proyecto
7 Conclusiones
8 Bibliografía
9 AnexosEspecializaciónEspecialista en Gerencia de Obras Civile
Crown Graphene Nanomeshes: Highly Stable Chelation-Doped Semiconducting Materials
Graphene nanomeshes (GNM's) formed by the creation of pore superlattices in
graphene, are a possible route to graphene-based electronics due to their
semiconducting properties, including the emergence of fractional eV band gaps.
The utility of GNM's would be markedly increased if a scheme to stably and
controllably dope them was developed. In this work, a chemically-motivated
approach to GNM doping based on selective pore-perimeter passivation and
subsequent ion chelation is proposed. It is shown by first-principles
calculations that ion chelation leads to stable doping of the passivated GNM's
-- both {\it n}- and {\it p}-doping are achieved within a rigid-band picture.
Such chelated or ``crown'' GNM structures are stable, high mobility
semiconducting materials possessing intrinsic doping-concentration control;
these can serve as building blocks for edge-free graphene nanoelectronics
including GNM-based complementary metal oxide semiconductor (CMOS)-type logic
switches.Comment: 18 pages, 6 figure
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Identification and characterization of dysregulated P-element induced wimpy testis-interacting RNAs in head and neck squamous cell carcinoma.
It is clear that alcohol consumption is a major risk factor in the pathogenesis of head and neck squamous cell carcinoma (HNSCC); however, the molecular mechanism underlying the pathogenesis of alcohol-associated HNSCC remains poorly understood. The aim of the present study was to identify and characterize P-element-induced wimpy testis (PIWI)-interacting RNAs (piRNAs) and PIWI proteins dysregulated in alcohol-associated HNSCC to elucidate their function in the development of this cancer. Using next generation RNA-sequencing (RNA-seq) data obtained from 40 HNSCC patients, the piRNA and PIWI protein expression of HNSCC samples was compared between alcohol drinkers and non-drinkers. A separate piRNA expression RNA-seq analysis of 18 non-smoker HNSCC patients was also conducted. To verify piRNA expression, reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was performed on the most differentially expressed alcohol-associated piRNAs in ethanol and acetaldehyde-treated normal oral keratinocytes. The correlation between piRNA expression and patient survival was analyzed using Kaplan-Meier estimators and multivariate Cox proportional hazard models. A comparison between alcohol drinking and non-drinking HNSCC patients demonstrated that a panel of 3,223 piRNA transcripts were consistently detected and differentially expressed. RNA-seq analysis and in vitro RT-qPCR verification revealed that 4 of these piRNAs, piR-35373, piR-266308, piR-58510 and piR-38034, were significantly dysregulated between drinking and non-drinking cohorts. Of these four piRNAs, low expression of piR-58510 and piR-35373 significantly correlated with improved patient survival. Furthermore, human PIWI-like protein 4 was consistently upregulated in ethanol and acetaldehyde-treated normal oral keratinocytes. These results demonstrate that alcohol consumption may cause dysregulation of piRNA expression in HNSCC and in vitro verifications identified 4 piRNAs that may be involved in the pathogenesis of alcohol-associated HNSCC
A French Fairy Tale Corpus syntactically and semantically annotated.
International audienceFairy tales, folktales and more generally children stories have lately attracted the Natural Language Processing (NLP) community. As such, very few corpora exist and linguistic resources are lacking. The work presented in this paper aims at filling this gap by presenting a syntactically and semantically annotated corpus. It focuses on the linguistic analysis of a Fairy Tales Corpus, and provides the description of the syntactic and semantic resources developed for Information Extraction. Resources include syntactic dependency relation annotation for 120 verbs; referential annotation, which is concerned with annotating each anaphoric occurrence and Proper Name with the most specific noun in the text; ontology matching for a substantial part of the nouns in the corpus; semantic role labelling for 41 verbs using the FrameNet database. The article also sums up previous analyses of this corpus and indicates possible uses of this corpus for the NLP community
CAL Dataflow Components for an MPEG RVC AVC Baseline Encoder
In this paper, an efficient H.264/AVC baseline encoder, described in RVC-CAL actor language, is introduced. The main aim of the paper is twofold: a) to demonstrate the flexibility and ease that is provided by RVC-CAL, which allows for efficient implementation of the presented encoder, and b) to shed light on the advantages that can be brought into the RVC framework by including such encoding tools. The main modules of the designed encoder include: Inter Frame Prediction (Motion Estimation/Compensation), Intra Frame Prediction, and Entropy Coding. Descriptions of the designed modules, accompanied with RVC-CAL design issues are provided. A comparison between different development approaches is also provided. The obtained results show that specifying complex video codecs (e.g. H.264/AVC encoder) using RVC-CAL followed by automatic translation into HDL, which is achievable by the tools that support the standard, results in more efficient HW implementation compared to the traditional HW design flow. A discussion that explains the reasons behind such results concludes the pape
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