2,844 research outputs found
Study and Application of Microwave Active Circuits with Negative Group Delay
This chapter is available on the following open access link: http://www.intechopen.com/books/microwave-and-millimeter-wave-technologies-modern-uwb-antennas-and-equipment/study-and-application-of-microwave-active-circuits-with-negative-group-delayA simple topology of an NGD active circuit consisting of a FET terminated by a shunt RLC-resonant network and dedicated to the microwave signals was proposed and extensively studied. To our knowledge, in this chapter, the first experimental time-domain demonstration of a circuit able to exhibit simultaneously gain and NGD in microwave domain is proposed. By injecting in the NGD circuit a sufficiently smoothed input short-pulse modulating a sine carrier, one gets an output having an envelop peak in advance compared with the input one. Of course, this phenomenon does not contradict the causality principle. It is also worth emphasizing that the tested circuit respects all required criteria of classical active microwave devices such as gain, matching and stability. As predicted in theory (Ravelo et al., 2007a, 2007b, 2007c and 2008a), for a prototype implemented in planar technology, we have measured in time-domain a pulse peak advance of about -2 ns or 24% of the 1/e-input pulse half-width without attenuation. It is also interesting to note that through this experimentation, the input noise contribution did not destroy the occurrence of time-domain advance induced by the NGD active circuit. Moreover, in this chapter, thanks to the S21-magnitude form, the understudied NGD circuit is able to exhibit a pulse compression phenomenon with a possibility of amplification. Then, it should be worth using the presented NGD active topology to compensate for dispersion effects and especially to reduce the intersymbol interference in certain telecommunication channels. As a potential application of this NGD circuit, a new principle of frequency independent phase shifter is proposed. By cascading a classical transmission line with this NGD circuit, a constant phase value is obtained. The efficiency of this principle was demonstrated by measurement. Indeed, a constant phase value of 90°±5° was obtained within a 76% relative frequency band centred at about 1.5 GHz. The impacts of the PS parameter variations and sensitivity analysis are stated. The main benefits of this NGD active PS concerns its compactness and also the facility to generate very low group delay, and the broad band characteristics. Besides, a two-stage NGD PS was also designed; the simulation results showed a bandwidth enhancement of the constant phase up to 125%. Some fields of applications such as the design of broadband active balun for RF front end architectures are discussed. As ongoing research, design of reconfigurable devices dedicated to telecommunication applications is envisaged. Future investigations will be devoted to the design of NGD devices able to operate at higher frequencies through the use of distributed elements. In this optic, the implementation of MMIC devices based on distributed elements is envisaged
Pré-dimensionnement par simulations dynamiques d’un réacteur de stockage thermochimique assurant l’autonomie d’un système solaire combiné.
peer reviewedEtude du stockage de l’énergie solaire thermique sous forme thermochimique comme moyen d’assurer l’autonomie thermique d’une habitation basse énergie. La surface de capteurs nécessaire et les caractéristiques du stockage sont étudiées par simulation dynamique (TRNSYS), de manière générale et pour des couples adsorbant/adsorbat particuliers (CaCl2/H2O et Charbon actif/Méthanol). Un système solaire combiné avec 14,4 m² de capteurs plans et un stockage thermochimique de 12,35 m³ de CaCl2 permet d’assurer l’autonomie thermique d’une habitation « basse énergie » située en Belgique et une grande part de la production d’eau chaude sanitaire (ECS).SOLAUTAR
Functional display of heterotetrameric human protein kinase CK2 on Escherichia coli: a novel tool for drug discovery
Background: Human protein kinase CK2 represents a novel therapeutic target for neoplastic diseases. Inhibitors are in need to explore the druggability and the therapeutic options of this enzyme. A bottleneck in the search for new inhibitors is the availability of the target for testing. Therefore an assay was developed to provide easy access to CK2 for discovery of novel inhibitors. Results: Autodisplay was used to present human CK2 on the surface of Escherichia coli. Heterotetrameric CK2 consists of two subunits, α and β, which were displayed individually on the surface. Co-display of CK2α and CK2β on the cell surface led to the formation of functional holoenzyme, as demonstrated by NaCl dependency of enzymatic activity, which differs from that of the catalytic subunit CK2α without β. In addition interaction of CK2α and CK2β at the cell surface was confirmed by co-immunoprecipitation assays. Surface displayed CK2 holoenzyme enabled an easy IC50 value determination. The IC50 values for the known CK2 inhibitors TBB and Silmitasertib were determined to be 50 and 3.3 nM, respectively. Conclusion: Surface-displayed CK2α and CK2β assembled on the cell surface of E. coli to an active tetrameric holoenzyme. The whole-cell CK2 autodisplay assay as developed is suitable for inhibition studies. Furthermore, it can be used to determine quantitative CK2 inhibition data such as IC50 values. In summary, this is the first report on the functional surface display of a heterotetrameric enzyme on E. coli.<br
Flavivirus NS3 and NS5 proteins interaction network: a high-throughput yeast two-hybrid screen
<p>Abstract</p> <p>Background</p> <p>The genus <it>Flavivirus </it>encompasses more than 50 distinct species of arthropod-borne viruses, including several major human pathogens, such as West Nile virus, yellow fever virus, Japanese encephalitis virus and the four serotypes of dengue viruses (DENV type 1-4). Each year, flaviviruses cause more than 100 million infections worldwide, some of which lead to life-threatening conditions such as encephalitis or haemorrhagic fever. Among the viral proteins, NS3 and NS5 proteins constitute the major enzymatic components of the viral replication complex and are essential to the flavivirus life cycle.</p> <p>Results</p> <p>We report here the results of a high-throughput yeast two-hybrid screen to identify the interactions between human host proteins and the flavivirus NS3 and NS5 proteins. Using our screen results and literature curation, we performed a global analysis of the NS3 and NS5 cellular targets based on functional annotation with the Gene Ontology features. We finally created the first flavivirus NS3 and NS5 proteins interaction network and analysed the topological features of this network. Our proteome mapping screen identified 108 human proteins interacting with NS3 or NS5 proteins or both. The global analysis of the cellular targets revealed the enrichment of host proteins involved in RNA binding, transcription regulation, vesicular transport or innate immune response regulation.</p> <p>Conclusions</p> <p>We proposed that the selective disruption of these newly identified host/virus interactions could represent a novel and attractive therapeutic strategy in treating flavivirus infections. Our virus-host interaction map provides a basis to unravel fundamental processes about flavivirus subversion of the host replication machinery and/or immune defence strategy.</p
Synthesis and biological evaluation of novel substituted pyrrolo[1,2-a]quinoxaline derivatives as inhibitors of the human protein kinase CK2
Herein we describe the synthesis and properties of substituted phenylaminopyrrolo[1,2-a]quinoxaline-carboxylic acid derivatives as a novel class of potent inhibitors of the human protein kinase CK2. A set of 15 compounds was designed and synthesized using convenient and straightforward synthesis protocols. The compounds were tested for inhibition of human protein kinase CK2, which is a potential drug target for many diseases including inflammatory disorders and cancer. New inhibitors with IC50 in the micro- and sub-micromolar range were identified. The most promising compound, the 4-[(3-chlorophenyl)amino]pyrrolo[1,2-a]quinoxaline-3-carboxylic acid 1c inhibited human CK2 with an IC50 of 49 nM. Our findings indicate that pyrrolo[1,2-a]quinoxalines are a promising starting scaffold for further development and optimization of human protein kinase CK2 inhibitorsFil: Guillon, Jean. Universite de Bordeaux; Francia;Fil: Le Borgne, Marc. Université de Lyon; Francia;Fil: Rimbault, Charlotte. Universite de Bordeaux; Francia;Fil: Moreau, Stéphane. Universite de Bordeaux; Francia;Fil: Savrimoutou, Solène. Universite de Bordeaux; Francia;Fil: Pinaud, Noël. Universite de Bordeaux; Francia;Fil: Baratin, Sophie. Universite de Bordeaux; Francia;Fil: Marchivie, Mathieu. Universite de Bordeaux; Francia;Fil: Roche, Séverine. Universite de Bordeaux; Francia;Fil: Bollacke, Andre. Institut für Pharmazeutische und Medizinische Chemie. Westfälische Wilhelms-Universität Münster; Alemania;Fil: Pecci, Adali. Consejo Nacional de Invest.cientif.y Tecnicas. Oficina de Coordinacion Administrativa Ciudad Universitaria. Instituto de Fisiol., Biol.molecular y Neurociencias; Argentina;Fil: Alvarez, Lautaro Damian. Consejo Nacional de Invest.cientif.y Tecnicas. Oficina de Coordinacion Administrativa Ciudad Universitaria. Unid.microanal.y Met.fisicos En Quim.org.(i); Universidad de Buenos Aires. Facultad de Cs.exactas y Naturales. Departamento de Quimica Organica;Fil: Desplat, Vanessa. Universite de Bordeaux; Francia;Fil: Joachim, Jose. Institut für Pharmazeutische und Medizinische Chemie. Westfälische Wilhelms-Universität Münster; Alemania
Transmisson Hub and Terminals for Point to Multipoint W-band TWEETHER System
The European Commission Horizon 2020 TWEETHER project will conclude the activity on September 2018 with the release of one transmission hub and three network terminal equipment for enabling the first W -band, 92–95 GHz, point to multipoint system, for high capacity backhaul and fixed access. The ambition of the project is to develop the European technology for a breakthrough in millimeter wave wireless networks, by introducing the use of traveling wave tubes to achieve the required transmission power for covering, by low-gain antennas, wide area sectors with radius longer than 1 km. The lack of transmission power has so far prevented the use of point to multipoint distribution at millimeter waves. At W -band, the 3 GHz bandwidth provides more than 10 Gbps capacity, and 4 Cbps/km 2 area capacity for small cells backhaul, with flexible allocation of the base stations and low total cost of operation. The TWEETHER system is also designed to provide high throughput fixed access. This paper will describe the latest results and the technological advancements the project generated, bringing Europe at the state of the art for point to multipoint millimeter wave wireless networks
Localized Surface Plasmon Resonance of Metallic Nanoparticles--Optical Property Characterization for Rational Applications
在光的激发下金属纳米结构中的自由电子能够发生群体性的振荡,进而产生表面等离激元(SPP)。发生等离激元共振时,金属纳米结构会将光束缚在表面,并在表面产生极强的电场增强。表面等离激元有两种类型:一类具有传播的特点,其表面等离激元能够在表面传播,称之为propagatingSPP;另一类不具有传播性,共振局域在一个很小的金属结构中,称之为localizedSPP,即局域表面等离激元共振(LSPR)。金属纳米颗粒就具有很强的表面等离激元共振的(LSPR)性质,使其对光产生增强的吸收和增强的散射,并表现出相关的热、光电场增强和热电子等效应。近年,随着纳米科技的发展,金属纳米粒子的LSPR效应已经成为一...The collective oscillation of free electrons in metal nanostructures excited with light is called surface plasmon polaritons (SPP). The light will be confined to a small area on the surface under the resonance condition (SPR), thus a giant enhancement in the electric field will be produced. There are two kinds of surface plasmon polaritons (SPP): one is propagating plasmon polaritons (PSPP), which...学位:理学博士院系专业:化学化工学院_物理化学(含化学物理)学号:2052010015366
French Roadmap for complex Systems 2008-2009
This second issue of the French Complex Systems Roadmap is the outcome of the
Entretiens de Cargese 2008, an interdisciplinary brainstorming session
organized over one week in 2008, jointly by RNSC, ISC-PIF and IXXI. It
capitalizes on the first roadmap and gathers contributions of more than 70
scientists from major French institutions. The aim of this roadmap is to foster
the coordination of the complex systems community on focused topics and
questions, as well as to present contributions and challenges in the complex
systems sciences and complexity science to the public, political and industrial
spheres
Genomic, Pathway Network, and Immunologic Features Distinguishing Squamous Carcinomas
This integrated, multiplatform PanCancer Atlas study co-mapped and identified distinguishing
molecular features of squamous cell carcinomas (SCCs) from five sites associated with smokin
Spatial Organization and Molecular Correlation of Tumor-Infiltrating Lymphocytes Using Deep Learning on Pathology Images
Beyond sample curation and basic pathologic characterization, the digitized H&E-stained images
of TCGA samples remain underutilized. To highlight this resource, we present mappings of tumorinfiltrating lymphocytes (TILs) based on H&E images from 13 TCGA tumor types. These TIL
maps are derived through computational staining using a convolutional neural network trained to
classify patches of images. Affinity propagation revealed local spatial structure in TIL patterns and
correlation with overall survival. TIL map structural patterns were grouped using standard
histopathological parameters. These patterns are enriched in particular T cell subpopulations
derived from molecular measures. TIL densities and spatial structure were differentially enriched
among tumor types, immune subtypes, and tumor molecular subtypes, implying that spatial
infiltrate state could reflect particular tumor cell aberration states. Obtaining spatial lymphocytic
patterns linked to the rich genomic characterization of TCGA samples demonstrates one use for
the TCGA image archives with insights into the tumor-immune microenvironment
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