8,146 research outputs found

    CMOS-3D smart imager architectures for feature detection

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    This paper reports a multi-layered smart image sensor architecture for feature extraction based on detection of interest points. The architecture is conceived for 3-D integrated circuit technologies consisting of two layers (tiers) plus memory. The top tier includes sensing and processing circuitry aimed to perform Gaussian filtering and generate Gaussian pyramids in fully concurrent way. The circuitry in this tier operates in mixed-signal domain. It embeds in-pixel correlated double sampling, a switched-capacitor network for Gaussian pyramid generation, analog memories and a comparator for in-pixel analog-to-digital conversion. This tier can be further split into two for improved resolution; one containing the sensors and another containing a capacitor per sensor plus the mixed-signal processing circuitry. Regarding the bottom tier, it embeds digital circuitry entitled for the calculation of Harris, Hessian, and difference-of-Gaussian detectors. The overall system can hence be configured by the user to detect interest points by using the algorithm out of these three better suited to practical applications. The paper describes the different kind of algorithms featured and the circuitry employed at top and bottom tiers. The Gaussian pyramid is implemented with a switched-capacitor network in less than 50 ÎŒs, outperforming more conventional solutions.Xunta de Galicia 10PXIB206037PRMinisterio de Ciencia e InnovaciĂłn TEC2009-12686, IPT-2011-1625-430000Office of Naval Research N00014111031

    Titanium alloy microstructure fingerprint plots from in-process machining

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    Titanium alloy components require several machining stages of forged billets which are supplied in a range of annealing conditions. Generally, the machining performance is influenced by the heat treatment and changes in billet microstructures are often overlooked by tool manufacturers and machinists. Due to the non-linear strain path during primary forging, titanium alloy billets are anisotropic in nature and require ex-situ non-destructive evaluation (NDE) during the manufacturing stages to ensure excellent service performance, particularly in safety-critical aerospace components. In this study, the local analysis of the fluctuations presented in the force response during face-turning operations is directly linked to the billet heat treatment condition and presented as microstructure fingerprint plots. The evolution of cutting forces in four different billet conditions of the alpha + beta titanium alloy Ti–6Al–2Sn–4Zr–6Mo (Ti-6246) was measured. The magnitude and fluctuations in force were directly correlated to microstructural features derived from the heat treatments. In addition, local spatial high-resolution synchronization of the cutting forces was used to determine the effects of microstructure from the heterogeneous upstream forging process and subsequent heat treatment. These rapidly produced microstructure fingerprint plots are an important development step for providing manufacturers with an in-process machining NDE method: this will help to qualify material upstream prior to expensive secondary forging or finish machining stages

    Super-resolution far-field ghost imaging via compressive sampling

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    Much more image details can be resolved by improving the system's imaging resolution and enhancing the resolution beyond the system's Rayleigh diffraction limit is generally called super-resolution. By combining the sparse prior property of images with the ghost imaging method, we demonstrated experimentally that super-resolution imaging can be nonlocally achieved in the far field even without looking at the object. Physical explanation of super-resolution ghost imaging via compressive sampling and its potential applications are also discussed.Comment: 4pages,4figure

    Single cell RNA sequencing of human FAPs reveals different functional stages in Duchenne muscular dystrophy

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    Copyright \ua9 2024 Fern\ue1ndez-Sim\uf3n, Pi\uf1ol-Jurado, Gokul-Nath, Unsworth, Alonso-P\ue9rez, Schiava, Nascimento, Tasca, Queen, Cox, Suarez-Calvet and D\uedaz-Manera.Background: Duchenne muscular dystrophy is a genetic disease produced by mutations in the dystrophin gene characterized by early onset muscle weakness leading to severe and irreversible disability. Muscle degeneration involves a complex interplay between multiple cell lineages spatially located within areas of damage, termed the degenerative niche, including inflammatory cells, satellite cells (SCs) and fibro-adipogenic precursor cells (FAPs). FAPs are mesenchymal stem cell which have a pivotal role in muscle homeostasis as they can either promote muscle regeneration or contribute to muscle degeneration by expanding fibrotic and fatty tissue. Although it has been described that FAPs could have a different behavior in DMD patients than in healthy controls, the molecular pathways regulating their function as well as their gene expression profile are unknown. Methods: We used single-cell RNA sequencing (scRNAseq) with 10X Genomics and Illumina technology to elucidate the differences in the transcriptional profile of isolated FAPs from healthy and DMD patients. Results: Gene signatures in FAPs from both groups revealed transcriptional differences. Seurat analysis categorized cell clusters as proliferative FAPs, regulatory FAPs, inflammatory FAPs, and myofibroblasts. Differentially expressed genes (DEGs) between healthy and DMD FAPs included upregulated genes CHI3L1, EFEMP1, MFAP5, and TGFBR2 in DMD. Functional analysis highlighted distinctions in system development, wound healing, and cytoskeletal organization in control FAPs, while extracellular organization, degradation, and collagen degradation were upregulated in DMD FAPs. Validation of DEGs in additional samples (n = 9) using qPCR reinforced the specific impact of pathological settings on FAP heterogeneity, reflecting their distinct contribution to fibro or fatty degeneration in vivo. Conclusion: Using the single-cell RNA seq from human samples provide new opportunities to study cellular coordination to further understand the regulation of muscle homeostasis and degeneration that occurs in muscular dystrophies

    Autopsie d’une membrane d’osmose inverse usagĂ©e prĂ©levĂ©e dans le Parc National du Banc d’Arguin (PNBA) en Mauritanie : cas d’étude de Teichitt

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    L’objectif de ce travail est d’étudier l’état de vieillissement d’une membrane d’osmose inverse (OI) usagĂ©e prĂ©levĂ©e en Mauritanie sur une unitĂ© de dessalement installĂ©e par la coopĂ©ration canarienne Ă  Teichitt dans le parc national du banc d’Arguin et de lui appliquer une dĂ©marche d’autopsie. L’usure de la membrane est caractĂ©risĂ©e par une augmentation significative de la permĂ©abilitĂ© hydraulique (25 % d’augmentation) et une diminution de la rĂ©tention en sels (10 % Ă  30 % de diminution). Un modĂšle de transfert de matiĂšre de type diffusion-convection permet de montrer l’augmentation du caractĂšre convectif du transfert, lorsque la pression transmembranaire augmente et en particulier au-delĂ  de 15 bars. Ainsi, l’usure de la membrane d’OI induit son rapprochement vers un transfert de matiĂšre combinĂ© de solubilisation-diffusion/convection, typique d’une opĂ©ration de nanofiltration (NF). L’analyse topographique par AFM de la surface de la membrane usagĂ©e en comparaison de la membrane neuve laisse apparaĂźtre des « cavitĂ©s » Ă  plusieurs endroits de la surface usagĂ©e traduisant la dĂ©gradation physique de celle-ci. De plus, la rugositĂ© de surface de la membrane usagĂ©e avec 74 nm est apparue supĂ©rieure Ă  celle de la membrane neuve avec 54 nm, ce qui nous informe de la prĂ©sence de matiĂšres colmatantes, dont la nature reste encore Ă  dĂ©terminer. Par contre, l’étude de la dĂ©gradation chimique des membranes usagĂ©es et neuves par la dĂ©termination de leur point isoĂ©lectrique (PIE) Ă  partir d’une mesure de potentiel d’écoulement transmembranaire ne montre pas de modifications significatives de ce paramĂštre (PIE = 2,5), preuve de la non-dĂ©gradation chimique interne de la membrane. Enfin, les rĂ©sultats d’une Ă©tude statistique prĂ©liminaire sont prĂ©sentĂ©s. Celle-ci consiste Ă  Ă©valuer l’hĂ©tĂ©rogĂ©nĂ©itĂ© de l’usure en matiĂšre de permĂ©abilitĂ© hydraulique et de rĂ©tention d’une solution de NaCl 0,1 M Ă  15 bars et 19 °C, pour six coupons diffĂ©rents pris sur les trois feuilles de membranes constituant le module d’osmose inverse usagĂ©. Une tendance se dĂ©gage, elle montre en particulier que l’usure est hĂ©tĂ©rogĂšne, non seulement au sein d’une mĂȘme feuille de membrane, mais aussi au sein des diffĂ©rentes membranes constituant le module. En rĂ©sumĂ©, il est observĂ© pour la premiĂšre fois qu’une vieille membrane d’OI employĂ©e pendant deux annĂ©es pour le dessalement d’eau de mer, dans les conditions d’utilisation sahariennes en Mauritanie (sans prĂ©-traitements), acquiert une microporositĂ© qui lui confĂšre les propriĂ©tĂ©s d’une membrane de nanofiltration.Currently used reverse osmosis (RO) membranes from desalination units are burned at the end of their life as membranes for seawater desalination. In the future, a possible alternative would be to reuse the old RO membranes as nanofiltration (NF), ultrafiltration (UF) or microfiltration (MF) membranes, i.e. for wastewater treatments, but before reuse, the level of RO membrane degradation must be evaluated by autopsy studies.Our goal in the present study was to demonstrate for the first time that a used RO membrane could be used for nanofiltration. The used RO membrane was purchased from a desalination bench scale unit based in the town of Teichitt (in north-west Nouakchott, Mauritania). Membrane autopsy studies showed an increase in its hydraulic permeability (25%) and a concurrent decrease in its salt rejection behaviour (10% to 30%). We also studied the modification of mass transfer before and after ageing, and demonstrated the onset of a convective component in the mass transfer of salts and an increase in membrane hydraulic permeability. Furthermore, the determination of the isoelectric point (IEP) of the membrane, using streaming potential measurements across the membranes, showed no change in IEP, with a value of 2.5 ± 0.2 . A preliminary study, based on a statistical evaluation of membrane degradation from hydraulic permeability and salt rejection experiments, showed heterogeneous wear of the membrane (most important in the centre). Finally, we observed for the first time that after two years of use for desalination, a used RO membrane had acquired a microporosity that corresponded to the properties of a new NF membrane

    Likelihood analysis of the pMSSM11 in light of LHC 13-TeV data

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    We use MasterCode to perform a frequentist analysis of the constraints on a phenomenological MSSM model with 11 parameters, the pMSSM11, including constraints from ∌36 /fb of LHC data at 13 TeV and PICO, XENON1T and PandaX-II searches for dark matter scattering, as well as previous accelerator and astrophysical measurements, presenting fits both with and without the (g−2)ÎŒ constraint. The pMSSM11 is specified by the following parameters: 3 gaugino masses M1,2,3 , a common mass for the first-and second-generation squarks mq~ and a distinct third-generation squark mass mq~3 , a common mass for the first-and second-generation sleptons mℓ~ and a distinct third-generation slepton mass mτ~ , a common trilinear mixing parameter A, the Higgs mixing parameter ÎŒ , the pseudoscalar Higgs mass MA and tanÎČ . In the fit including (g−2)ÎŒ , a Bino-like χ~01 is preferred, whereas a Higgsino-like χ~01 is mildly favoured when the (g−2)ÎŒ constraint is dropped. We identify the mechanisms that operate in different regions of the pMSSM11 parameter space to bring the relic density of the lightest neutralino, χ~01 , into the range indicated by cosmological data. In the fit including (g−2)ÎŒ , coannihilations with χ~02 and the Wino-like χ~±1 or with nearly-degenerate first- and second-generation sleptons are active, whereas coannihilations with the χ~02 and the Higgsino-like χ~±1 or with first- and second-generation squarks may be important when the (g−2)ÎŒ constraint is dropped. In the two cases, we present χ2 functions in two-dimensional mass planes as well as their one-dimensional profile projections and best-fit spectra. Prospects remain for discovering strongly-interacting sparticles at the LHC, in both the scenarios with and without the (g−2)ÎŒ constraint, as well as for discovering electroweakly-interacting sparticles at a future linear e+e− collider such as the ILC or CLIC

    A new multicompartmental reaction-diffusion modeling method links transient membrane attachment of E. coli MinE to E-ring formation

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    Many important cellular processes are regulated by reaction-diffusion (RD) of molecules that takes place both in the cytoplasm and on the membrane. To model and analyze such multicompartmental processes, we developed a lattice-based Monte Carlo method, Spatiocyte that supports RD in volume and surface compartments at single molecule resolution. Stochasticity in RD and the excluded volume effect brought by intracellular molecular crowding, both of which can significantly affect RD and thus, cellular processes, are also supported. We verified the method by comparing simulation results of diffusion, irreversible and reversible reactions with the predicted analytical and best available numerical solutions. Moreover, to directly compare the localization patterns of molecules in fluorescence microscopy images with simulation, we devised a visualization method that mimics the microphotography process by showing the trajectory of simulated molecules averaged according to the camera exposure time. In the rod-shaped bacterium _Escherichia coli_, the division site is suppressed at the cell poles by periodic pole-to-pole oscillations of the Min proteins (MinC, MinD and MinE) arising from carefully orchestrated RD in both cytoplasm and membrane compartments. Using Spatiocyte we could model and reproduce the _in vivo_ MinDE localization dynamics by accounting for the established properties of MinE. Our results suggest that the MinE ring, which is essential in preventing polar septation, is largely composed of MinE that is transiently attached to the membrane independently after recruited by MinD. Overall, Spatiocyte allows simulation and visualization of complex spatial and reaction-diffusion mediated cellular processes in volumes and surfaces. As we showed, it can potentially provide mechanistic insights otherwise difficult to obtain experimentally

    The dimorphic diaspore model Aethionema arabicum (Brassicaceae):Distinct molecular and morphological control of responses to parental and germination temperatures

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    Plants in habitats with unpredictable conditions are often characterized by diversifying their bet-hedging strategies that ensure fitness over a wider range of variable environmental factors. A striking example is the diaspore (seed and fruit) heteromorphism that evolved to maximize species survival in Aethionema arabicum (Brassicaceae) in which external and endogenous triggers allow the production of two distinct diaspores on the same plant. Using this dimorphic diaspore model, we identified contrasting molecular, biophysical, and ecophysiological mechanisms in the germination responses to different temperatures of the mucilaginous seeds (M+ seed morphs), the dispersed indehiscent fruits (IND fruit morphs), and the bare non-mucilaginous M- seeds obtained by pericarp (fruit coat) removal from IND fruits. Large-scale comparative transcriptome and hormone analyses of M+ seeds, IND fruits, and M- seeds provided comprehensive datasets for their distinct thermal responses. Morph-specific differences in co-expressed gene modules in seeds, as well as seed and pericarp hormone contents identified a role of the IND pericarp in imposing coat dormancy by generating hypoxia affecting ABA sensitivity. This involved expression of morph-specific transcription factors, hypoxia response and cell wall-remodeling genes, as well as altered abscisic acid (ABA) metabolism, transport, and signaling. Parental temperature affected ABA contents and ABA-related gene expression and altered IND pericarp biomechanical properties. Elucidating the molecular framework underlying the diaspore heteromorphism can provide insight into developmental responses to globally changing temperatures
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