573 research outputs found

    End-of-fabrication CMOS process monitor

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    A set of test 'modules' for verifying the quality of a complementary metal oxide semiconductor (CMOS) process at the end of the wafer fabrication is documented. By electrical testing of specific structures, over thirty parameters are collected characterizing interconnects, dielectrics, contacts, transistors, and inverters. Each test module contains a specification of its purpose, the layout of the test structure, the test procedures, the data reduction algorithms, and exemplary results obtained from 3-, 2-, or 1.6-micrometer CMOS/bulk processes. The document is intended to establish standard process qualification procedures for Application Specific Integrated Circuits (ASIC's)

    Product assurance technology for custom LSI/VLSI electronics

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    The technology for obtaining custom integrated circuits from CMOS-bulk silicon foundries using a universal set of layout rules is presented. The technical efforts were guided by the requirement to develop a 3 micron CMOS test chip for the Combined Release and Radiation Effects Satellite (CRRES). This chip contains both analog and digital circuits. The development employed all the elements required to obtain custom circuits from silicon foundries, including circuit design, foundry interfacing, circuit test, and circuit qualification

    Product assurance technology for procuring reliable, radiation-hard, custom LSI/VLSI electronics

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    Advanced measurement methods using microelectronic test chips are described. These chips are intended to be used in acquiring the data needed to qualify Application Specific Integrated Circuits (ASIC's) for space use. Efforts were focused on developing the technology for obtaining custom IC's from CMOS/bulk silicon foundries. A series of test chips were developed: a parametric test strip, a fault chip, a set of reliability chips, and the CRRES (Combined Release and Radiation Effects Satellite) chip, a test circuit for monitoring space radiation effects. The technical accomplishments of the effort include: (1) development of a fault chip that contains a set of test structures used to evaluate the density of various process-induced defects; (2) development of new test structures and testing techniques for measuring gate-oxide capacitance, gate-overlap capacitance, and propagation delay; (3) development of a set of reliability chips that are used to evaluate failure mechanisms in CMOS/bulk: interconnect and contact electromigration and time-dependent dielectric breakdown; (4) development of MOSFET parameter extraction procedures for evaluating subthreshold characteristics; (5) evaluation of test chips and test strips on the second CRRES wafer run; (6) two dedicated fabrication runs for the CRRES chip flight parts; and (7) publication of two papers: one on the split-cross bridge resistor and another on asymmetrical SRAM (static random access memory) cells for single-event upset analysis

    Cystadénocarcinome de la base de la langue

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    Introduction: Les cancers de la base de langue sont des tumeurs agressives et silencieuses. Le cystadénocarcinome est une tumeur maligne du tissu glandulaire ayant une composante kystique intéressant principalement les glandes salivaires accessoires.Observation: Nous rapportons le cas d’un patient âgé de 78 ans, qui a consulté pour une dysphagie haute aux solides évoluant depuis 2 ans, sans notion de dyspnée ni de dysphonie. Une formation kystique de la base de la langue a été mise en évidence. on a complété par un examen tomodensitométrique et une iRm qui ont montré une formation bienlimitée mesurant 3 cm aux dépens de la base de la langue, latéralisée à droite et comblant partiellement la vallécule droite. Le patient a été opéré par voie cervicale infra mandibulaire avec exérèse chirurgicale en monobloc et l’examen anatomopathologique a conclut à un  cystadénocarcinome lingual. Un curage fonctionnel bilatéral a été pratiqué complété ensuite par une radiothérapie.Conclusion: Le cystadénocarcinome de la base de la langue est une entité très rare. La symptomatologie clinique est pauvre. Les métastases ganglionnaires sont fréquentes. La tomodensitométrie et l’imagerie par résonance magnétique sont nécessaires pour approcher la nature et l’extension de la tumeur. Le traitement est chirurgical et peut être suivi d’une radiothérapie.Mots Cles: cystadenocarcinome, base de langue, chirurgi

    Repeated games for eikonal equations, integral curvature flows and non-linear parabolic integro-differential equations

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    The main purpose of this paper is to approximate several non-local evolution equations by zero-sum repeated games in the spirit of the previous works of Kohn and the second author (2006 and 2009): general fully non-linear parabolic integro-differential equations on the one hand, and the integral curvature flow of an interface (Imbert, 2008) on the other hand. In order to do so, we start by constructing such a game for eikonal equations whose speed has a non-constant sign. This provides a (discrete) deterministic control interpretation of these evolution equations. In all our games, two players choose positions successively, and their final payoff is determined by their positions and additional parameters of choice. Because of the non-locality of the problems approximated, by contrast with local problems, their choices have to "collect" information far from their current position. For integral curvature flows, players choose hypersurfaces in the whole space and positions on these hypersurfaces. For parabolic integro-differential equations, players choose smooth functions on the whole space

    MESOTHELIUM PERICARDIQUE PRIMITIF SIMULANT UN KYSTE HYDATIQUE PERICARDIQUE

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    The mesothelioma of pericardium is a rare tumor. Its clinical presentation is polymorphous and its diagnosis is especially histological. We report a case of 63 years old women who presented, one month before, dyspnea on exertion which evolved to orthopnea, associated to atypical thoracic pain, admitted in intensive care unit for symptoms of compressive effusion. Transthoracic echocardiography was favourable of hydatid cyst of pericardium. A thoracotomy, following cardio-circulatory arrest, showed cystic tumor of pericardium invading the left auricle, mediastinal pleura and the left pulmonary hilum. Histopathologic examination confirmed the diagnosis of mesothelioma of pericardium.Le mésothélium péricardique primitif malin est une tumeur rare. Sa présentation clinique est polymorphe et son diagnostic est surtout histologique. Nous rapportons le cas d’une patiente âgée de 63 ans ayant présenté, un mois auparavant, une dyspnée d’effort ayant évolué vers l’orthopnée et associée à des douleurs thoraciques atypiques, a été admise au service des urgences dans un tableau de pré-tamponnade. L’échocardiographie transthoracique était en faveur d’un kyste hydatique péricardique avec compression des cavités cardiaques droites. Suite à un arrêt cardio-circulatoire, une thoracotomie de sauvetage a montré une masse kystique péricardique envahissant l’oreillette gauche, la plèvre mediastinale et le hile pulmonaire gauches. L’examen anatomopathologique à l’autopsie a objectivé un mésothélium péricardique primitif malin

    Conformational adaptation of Asian macaque TRIMCyp directs lineage specific antiviral activity

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    TRIMCyps are anti-retroviral proteins that have arisen independently in New World and Old World primates. All TRIMCyps comprise a CypA domain fused to the tripartite domains of TRIM5α but they have distinct lentiviral specificities, conferring HIV-1 restriction in New World owl monkeys and HIV-2 restriction in Old World rhesus macaques. Here we provide evidence that Asian macaque TRIMCyps have acquired changes that switch restriction specificity between different lentiviral lineages, resulting in species-specific alleles that target different viruses. Structural, thermodynamic and viral restriction analysis suggests that a single mutation in the Cyp domain, R69H, occurred early in macaque TRIMCyp evolution, expanding restriction specificity to the lentiviral lineages found in African green monkeys, sooty mangabeys and chimpanzees. Subsequent mutations have enhanced restriction to particular viruses but at the cost of broad specificity. We reveal how specificity is altered by a scaffold mutation, E143K, that modifies surface electrostatics and propagates conformational changes into the active site. Our results suggest that lentiviruses may have been important pathogens in Asian macaques despite the fact that there are no reported lentiviral infections in current macaque populations

    Polymorphisms in the α4 Integrin of Neotropical Primates: Insights for Binding of Natural Ligands and HIV-1 gp120 to the Human α4β7

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    The α4 integrin subunit associates with β7 and β1 and plays important roles in immune function and cell trafficking. The gut-homing receptor α4β7 has been recently described as a new receptor for HIV. Here, we describe polymorphisms of ITGA4 gene in New World primates (NWP), and tested their impact on the binding to monoclonal antibodies, natural ligands (MAdCAM and VCAM), and several gp120 HIV-1 envelope proteins. Genomic DNA of NWP specimens comprising all genera of the group had their exons 5 and 6 (encoding the region of binding to the ligands studied) analyzed. The polymorphisms found were introduced into an ITGA4 cDNA clone encoding the human α4 subunit. Mutant α4 proteins were co-expressed with β7 and were tested for binding of mAbs, MAdCAM, VCAM and gp120 of HIV-1, which was compared to the wild-type (human) α4. Mutant α4 proteins harboring the K201E/I/N substitution had reduced binding of all ligands tested, including HIV-1 gp120 envelopes. The mAbs found with reduced biding included one from which a clinically-approved drug for the treatment of neurological disorders has been derived. α4 polymorphisms in other primate species may influence outcomes in the development and treatment of infectious and autoimmune diseases in humans and in non-human primates

    Host cell species-specific effect of cyclosporine A on simian immunodeficiency virus replication

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    <p>Abstract</p> <p>Background</p> <p>An understanding of host cell factors that affect viral replication contributes to elucidation of the mechanism for determination of viral tropism. Cyclophilin A (CypA), a peptidyl-prolyl <it>cis-trans </it>isomerase (PPIase), is a host factor essential for efficient replication of human immunodeficiency virus type 1 (HIV-1) in human cells. However, the role of cyclophilins in simian immunodeficiency virus (SIV) replication has not been determined. In the present study, we examined the effect of cyclosporine A (CsA), a PPIase inhibitor, on SIV replication.</p> <p>Results</p> <p>SIV replication in human CEM-SS T cells was not inhibited but rather enhanced by treatment with CsA, which inhibited HIV-1 replication. CsA treatment of target human cells enhanced an early step of SIV replication. CypA overexpression enhanced the early phase of HIV-1 but not SIV replication, while CypA knock-down resulted in suppression of HIV-1 but not SIV replication in CEM-SS cells, partially explaining different sensitivities of HIV-1 and SIV replication to CsA treatment. In contrast, CsA treatment inhibited SIV replication in macaque T cells; CsA treatment of either virus producer or target cells resulted in suppression of SIV replication. SIV infection was enhanced by CypA overexpression in macaque target cells.</p> <p>Conclusions</p> <p>CsA treatment enhanced SIV replication in human T cells but abrogated SIV replication in macaque T cells, implying a host cell species-specific effect of CsA on SIV replication. Further analyses indicated a positive effect of CypA on SIV infection into macaque but not into human T cells. These results suggest possible contribution of CypA to the determination of SIV tropism.</p

    Optical microscopy in the nano-world

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    Scanning near-field optical microscopy (SNOM) is an optical microscopy whose resolution is not bound to the diffraction limit. It provides chemical information based upon spectral, polarization and/or fluorescence contrast images. Details as small as 20 nm can be recognized. Photophysical and photochemical effects can be studied with SNOM on a similar scale. This article reviews a good deal of the experimental and theoretical work on SNOM in Switzerland
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