Search results for "Signal"
showing 10 items of 6924 documents
Active lighting applied to three dimensional reconstruction of specular metallic surfaces by polarization imaging
2005
This thesis deals with a new automated tridimensional inspection system for specular metallic surfaces, based on polarization analysis. We first present an extension of the ‘Shape from Polarization' method for dielectric to metallic surfaces. After being reflected, an unpolarized light wave becomes partially linearly polarized, depending on the surface normal and on the refractive index of the media it impinges on. Hence, by measuring the polarization parameters of the reflected light, the surface normals are computed. The ambiguity concerning the normals orientation is solved here with a new active lighting system. Then, we describe and compare numerical methods for reconstructing the trid…
Moving RTS/CTS to the frequency domain: an efficient contention scheme for 802.11ax networks
2019
In this paper, we propose a contention mechanism based on the execution of multiple contention rounds in the frequency domain (ReCHo), which is designed to offer high throughput performance and robustness with respect to imperfect carrier sensing. The main idea is using narrow tones as signalling messages for performing channel access contentions and allowing the Access Point (AP) to echo these signals, in order to extend the sensing capabilities to all the stations associated to the AP. In particular, we refer to the emerging IEEE 802.11ax standard, showing how our scheme can boost performance of random access with respect to the current version of IEEE 802.11ax OFDMA Back-Off (OBO), even …
'Good to Repeat': Making Random Access Near-Optimal with Repeated Contentions
2020
Recent advances on WLAN technology have been focused mostly on boosting network capacity by means of a more efficient and flexible physical layer. A new concept is required at MAC level to exploit fully the new capabilities of the PHY layer. In this article, we propose a contention mechanism based on Repeated Contentions (ReCo) in frequency domain. It provides a simple-to-configure, robust and short-term fair algorithm for the random contention component of the MAC protocol. The throughput efficiency of ReCo is not sensitive to the number of contending stations, so that ReCo does not require adaptive tuning of the access parameters for performance optimization. Efficiency and robustness is …
Classification of healthy, Alzheimer and Parkinson populations with a multi-branch neural network
2022
Signal processing, for delimitation of the target events and parametrization, is usually required when instrumented assessment is conducted to determine an individual’s functional status. However, these procedures may rule out relevant information obtained by sensors. To prevent this, the use of models based on neural networks that automatically extract relevant features from the raw signal may improve the characterization of the functional status. Thus, the aim of the study was to determine the classification accuracy of a multi-head convolutional layered neural network (CNN) using a simple functional mobility test in people with different conditions. The raw data from an inertial sensor e…
The effect of nanoparticle size and NLS density on nuclear targeting in cancer and normal cells; impaired nuclear import and aberrant nanoparticle in…
2017
The cell nucleus is an interesting target in many diseases with particular interest in cancer. Previously, nuclear targeted small and large chitosan nanoparticles (S-NPs≈25nm, and L-NPs≈150nm respectively), modified with low, intermediate and high densities of NLS (L-NLS, I-NLS and H-NLS) were developed and assessed in L929 fibroblasts. However, to evade apoptosis and stimulate tumor growth cancer cells are capable of manipulating the nuclear-cytoplasmic transport on many levels, making NPs that are capable of nuclear targeting in normal cells incapable of doing so in cancer. For such reason, here, the nuclear delivery efficiency of S-NPs and L-NPs was assessed as a function of their NLS de…
Nitrated Fatty Acids Modulate the Physical Properties of Model Membranes and the Structure of Transmembrane Proteins
2017
Nitrated fatty acids (NO2 -FAs) act as anti-inflammatory signal mediators, albeit the molecular mechanisms behind NO2 -FAs' influence on diverse metabolic and signaling pathways in inflamed tissues are essentially elusive. Here, we combine fluorescence measurements with surface-specific sum frequency generation vibrational spectroscopy and coarse-grained computer simulations to demonstrate that NO2 -FAs alter lipid organization by accumulation at the membrane-water interface. As the function of membrane proteins strongly depends on both, protein structure as well as membrane properties, we consecutively follow the structural dynamics of an integral membrane protein in presence of NO2 -FAs. …
The Myristoylated Alanine-Rich C-Kinase Substrate (MARCKS) is Sequentially Phosphorylated by Conventional, Novel and Atypical Isotypes of Protein Kin…
1995
The myristoylated alanine-rich C-kinase substrate (MARCKS) is the major protein kinase C (PKC) substrate in many cell types including fibroblasts and brain cells. Here we describe the phosphorylation of MARCKS and the site specificity for different PKC isotypes. Conventional (c)PKC beta 1, novel (n)PKC delta and nPKC epsilon efficiently phosphorylated the MARCKS protein in vitro. The Km values were extremely low, reflecting a high affinity between kinases and substrate. The apparent affinity of nPKC delta (Km = 0.06 microM) was higher than that of nPKC epsilon and cPKC beta 1 (Km = 0.32 microM). The rate of substrate phosphorylation was inversely correlated with affinity and decreased in th…
Molecular basis of early epithelial response to streptococcal exotoxin: role of STIM1 and Orai1 proteins
2011
Streptolysin O (SLO) is a cholesterol-dependent cytolysin (CDC) from Streptococcus pyogenes. SLO induces diverse types of Ca(2+) signalling in host cells which play a key role in membrane repair and cell fate determination. The mechanisms behind SLO-induced Ca(2+) signalling remain poorly understood. Here, we show that in NCI-H441 cells, wild-type SLO as well as non-pore-forming mutant induces long-lasting intracellular Ca(2+) oscillations via IP(3) -mediated depletion of intracellular stores and activation of store-operated Ca(2+) (SOC) entry. SLO-induced activation of SOC entry was confirmed by Ca(2+) add-back experiments, pharmacologically and by overexpression as well as silencing of ST…
IP 3 signalling regulates exogenous RNA i in C aenorhabditis elegans
2015
RNA interference (RNAi) is a widespread and widely exploited phenomenon. Here, we show that changing inositol 1,4,5-trisphosphate (IP3) signalling alters RNAi sensitivity in Caenorhabditis elegans. Reducing IP3 signalling enhances sensitivity to RNAi in a broad range of genes and tissues. Conversely up-regulating IP3 signalling decreases sensitivity. Tissue-specific rescue experiments suggest IP3 functions in the intestine. We also exploit IP3 signalling mutants to further enhance the sensitivity of RNAi hypersensitive strains. These results demonstrate that conserved cell signalling pathways can modify RNAi responses, implying that RNAi responses may be influenced by an animal's physiology…
VERS UNE ARCHITECTURE UNIFIÉE ET ZÉRO TEMPS MORT POUR L'INSTRUMENTATION NUCLÉAIRE
2014
National audience; Dans l’instrumentation nucléaire, et d’autres domaines tels que les applications de la physique des particules, l’analyse de signaux médicaux (Tomographie par Emission de Positons (TEP), Electro-EncephaloGraphie (EEG)) ou la détection de signaux radar, le signal mesuré est composé d’impulsions dont la date d’arrivée est aléatoire, et dont l’amplitude et la durée sont non-d´eterministes. La grande variété d’applications nécessite de disposer d’une architecture flexible pouvant être aisément reprogrammée. De plus, l’exigence de mesures en temps réel impose de disposer d’une grande capacité de calcul et de bande passante pour la mise en forme et l’extraction des caractéristi…