195 research outputs found

    Properties of Cd1-xZnx Te crystals grown by High Pressure Bridgman (HPB)

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    In this paper we present results of a modelling of the current-voltage characteristics of metal/ultra-thin oxide/semiconductor structures with negatively biased metal gate (V<0), when the oxide thickness varies from 45Å to 80Å. We analyze the theoretical influence of the temperature and Schottky effect on the Fowler-Nordheim (FN) conduction. The results obtained show that these influences depend on the electric field in the oxide and on the potential barrier at the metal/oxide interface. At the ambient temperature, the influence on this potential barrier is lower than 1.5%. However, it can reach 45% on the pre-exponential coefficient of the FN current. It is therefore necessary to consider in the FN classical conduction expression a correction term that takes account the temperature and Schottky effects. These results are validated experimentally by modelling the current-voltage characteristics of the realized structures at high field.In this paper we present results of a modelling of the current-voltage characteristics of metal/ultra-thin oxide/semiconductor structures with negatively biased metal gate (V<0), when the oxide thickness varies from 45Å to 80Å. We analyze the theoretical influence of the temperature and Schottky effect on the Fowler-Nordheim (FN) conduction. The results obtained show that these influences depend on the electric field in the oxide and on the potential barrier at the metal/oxide interface. At the ambient temperature, the influence on this potential barrier is lower than 1.5%. However, it can reach 45% on the pre-exponential coefficient of the FN current. It is therefore necessary to consider in the FN classical conduction expression a correction term that takes account the temperature and Schottky effects. These results are validated experimentally by modelling the current-voltage characteristics of the realized structures at high field

    Dacryocystostomies par voieendonasale:indications et technique chirurgicale

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    Introduction : La dacryocystorhinostomie consiste à dériver le contenu du sac lacrymal directement vers la lumière de la fosse nasale correspondante en réalisant une large ouverture dans la paroi osseuse et muqueuse du sac, court-circuitant ainsi le canal lacrymonasal obturé. nous nous proposons, à travers cette étude rétrospective, de discuter les aspects techniques chirurgicaux de la dacryocystostomie par voie endonasale et de revoir les indications opératoires.Mots-clefs : dacryocystite ; dacryocystorhinostomie ; chirurgie endonasaleThe purpose of dacryocystorhinostomy is to derive the content of the lacrimal sac directly into the light of the corresponding nasal cavity by making a large opening in the bony wall and sac mucosa, by passing the blocked nasolacrimal duct. We intend, through this retrospective study, discuss the technical aspects of surgical dacryocystostomy by endonasal and review the indications for surgery.Keywords : dacryocystitis; dacryocystorhinostomy; endonasal surgery

    Adhesive and conformational behaviour of mycolic acid monolayers

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    We have studied the pH-dependent interaction between mycolic acid (MA) monolayers and hydrophobic and hydrophilic surfaces using molecular (colloidal probe) force spectroscopy. In both cases, hydrophobic and hydrophilic monolayers (prepared by Langmuir-Blodgett and Langmuir-Schaefer deposition on silicon or hydrophobized silicon substrates, respectively) were studied. The force spectroscopy data, fitted with classical DLVO (Derjaguin, Landau, Verwey, and Overbeek) theory to examine the contribution of electrostatic and van der Waals forces, revealed that electrostatic forces are the dominant contribution to the repulsive force between the approaching colloidal probe and MA monolayers. The good agreement between data and the DLVO model suggest that beyond a few nm away from the surface, hydrophobic, hydration, and specific chemical bonding are unlikely to contribute to any significant extent to the interaction energy between the probe and the surface. The pH-dependent conformation of MA molecules in the monolayer at the solid-liquid interface was studied by ellipsometry, neutron reflectometry, and with a quartz crystal microbalance. Monolayers prepared by the Langmuir-Blodgett method demonstrated a distinct pH-responsive behaviour, while monolayers prepared by the Langmuir-Schaefer method were less sensitive to pH variation. It was found that the attachment of water molecules plays a vital role in determining the conformation of the MA monolayers. (C) 2010 Elsevier B.V. All rights reserved

    Comparative Study of Human and Automated Screening for Antinuclear Antibodies by Immunofluorescence on HEp-2 Cells

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    Background: Several automated systems had been developed in order to reduce inter-observer variability in indirect immunofluorescence (IIF) interpretation. We aimed to evaluate the performance of a processing system in antinuclear antibodies (ANA) screening on HEp-2 cells. Patients and Methods: This study included 64 ANA-positive sera and 107 ANA-negative sera that underwent IIF on two commercial kits of HEp-2 cells (BioSystems® and Euroimmun®). IIF results were compared with a novel automated interpretation system, the “CyclopusCADImmuno®” (CAD). Results: All ANA-positive sera images were recognized as positive by CAD (sensitivity = 100%), while 17 (15.9%) of the ANA-negative sera images were interpreted as positive (specificity = 84.1%), =0.799 (SD=0.045). Comparison of IIF pattern determination between human and CAD system revealed on HEp-2 (BioSystems®), a complete concordance in 6 (9.37%) sera, a partial concordance (sharing of at least 1 pattern) in 42 (65.6%) cases and in 16 (25%) sera the pattern interpretation was discordant. Similarly, on HEp-2 (Euroimmun®) the concordance in pattern interpretation was total in 5 (7.8%) sera, partial in 39 (60.9%) and absent in 20 (31.25%). For both tested HEp-2 cells kits agreement was enhanced for the most common patterns, homogenous, fine speckled and coarse speckled. While there was an issue in identification of nucleolar, dots and nuclear membranous patterns by CAD. Conclusion: Assessment of ANA by IIF on HEp-2 cells using the automated interpretation system, the “CyclopusCADImmuno®” is a reliable method for positive/negative differentiation. Continuous integration of IIF images would improve the pattern identification by the CAD

    Deep-level defects in n-type GaAsBi alloys grown by molecular beam epitaxy at low temperature and their influence on optical properties

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    Deep-level defects in n-type GaAs1-x Bi x having 0 ≤ x ≤ 0.023 grown on GaAs by molecular beam epitaxy at substrate temperature of 378 °C have been injvestigated by deep level transient spectroscopy. The optical properties of the layers have been studied by contactless electroreflectance and photoluminescence. We find that incorporating Bi suppresses the formation of GaAs-like electron traps, thus reducing the total trap concentration in dilute GaAsBi layers by over two orders of magnitude compared to GaAs grown under the same conditions. In order to distinguish between Bi- and host-related traps and to identify their possible origin, we used the GaAsBi band gap diagram to correlate their activation energies in samples with different Bi contents. This approach was recently successfully applied for the identification of electron traps in n-type GaAs1-x N x and assumes that the activation energy of electron traps decreases with the Bi (or N)-related downward shift of the conduction band. On the basis of this diagram and under the support of recent theoretical calculations, at least two Bi-related traps were revealed and associated with Bi pair defects, i.e. (VGa+BiGa)(-/2-) and (AsGa+BiGa)(0/1-). In the present work it is shown that these defects also influence the photoluminescence properties of GaAsBi alloys

    Preliminary results of the project A.I.D.A. (Auto Immunity: Diagnosis Assisted by computer)

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    In this paper, are presented the preliminary results of the A.I.D.A. (Auto Immunity: Diagnosis Assisted by computer) project which is developed in the frame of the cross-border cooperation Italy-Tunisia. According to the main objectives of this project, a database of interpreted Indirect ImmunoFluorescence (IIF) images on HEp 2 cells is being collected thanks to the contribution of Italian and Tunisian experts involved in routine diagnosis of autoimmune diseases. Through exchanging images and double reporting; a Gold Standard database, containing around 1000 double reported IIF images with different patterns including negative tests, has been settled. This Gold Standard database has been used for optimization of a computing solution (CADComputer Aided Detection) and for assessment of its added value in order to be used along with an immunologist as a second reader in detection of auto antibodies for autoimmune disease diagnosis. From the preliminary results obtained, the CAD appeared more powerful than junior immunologists used as second readers and may significantly improve their efficacy

    Computer-Assisted Classification Patterns in Autoimmune Diagnostics: The AIDA Project

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    Antinuclear antibodies (ANAs) are significant biomarkers in the diagnosis of autoimmune diseases in humans, done by mean of Indirect ImmunoFluorescence (IIF)method, and performed by analyzing patterns and fluorescence intensity. This paper introduces the AIDA Project (autoimmunity: diagnosis assisted by computer) developed in the framework of an Italy-Tunisia cross-border cooperation and its preliminary results. A database of interpreted IIF images is being collected through the exchange of images and double reporting and a Gold Standard database, containing around 1000 double reported images, has been settled. The Gold Standard database is used for optimization of aCAD(Computer AidedDetection) solution and for the assessment of its added value, in order to be applied along with an Immunologist as a second Reader in detection of autoantibodies. This CAD system is able to identify on IIF images the fluorescence intensity and the fluorescence pattern. Preliminary results show that CAD, used as second Reader, appeared to perform better than Junior Immunologists and hence may significantly improve their efficacy; compared with two Junior Immunologists, the CAD system showed higher Intensity Accuracy (85,5% versus 66,0% and 66,0%), higher Patterns Accuracy (79,3% versus 48,0% and 66,2%), and higher Mean Class Accuracy (79,4% versus 56,7% and 64.2%)

    Spesolimab treatment for the prevention of flares in people with generalized pustular psoriasis (GPP): a plain language summary of the Effisayil ™ 2 study

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    What is this study about?: Generalized pustular psoriasis (shortened to GPP) is a rare, potentially life-threatening disease in which pus-filled blisters or pustules may suddenly form all over the body. The drug spesolimab has been approved to treat worsening GPP (known as flares) in many countries. However, it was not known if spesolimab could prevent the symptoms of GPP. This summary reports the results from a clinical study called Effisayil™ 2, that was done to understand if spesolimab was a safe and effective way to prevent flares in people with GPP. In the study, 123 participants, recruited in 20 different countries, were given one of three different doses of spesolimab (low, medium, or high) or a non-active medicine (placebo) over 48 weeks. What were the results?: Participants who received spesolimab had fewer GPP flares over the course of the 48-week study. Different doses of the drug were tested and compared to placebo, and a high dose of spesolimab worked better than low and medium doses. Using spesolimab also reduced the chance of developing skin symptoms, such as redness or pustules, and prevented quality of life getting worse over 48 weeks. While some participants experienced unwanted effects, they were mostly mild or moderate and most did not appear to be caused by spesolimab, or the dose at which it was given. What do the results of the study mean?: The results indicate that a high dose of spesolimab works well to prevent GPP flares and stop the disease getting worse. Health authorities are looking at the results of this study to decide if spesolimab can also be prescribed for the prevention of GPP flares

    Ultralong C100 Mycolic Acids Support the Assignment of Segniliparus as a New Bacterial Genus

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    Mycolic acid-producing bacteria isolated from the respiratory tract of human and non-human mammals were recently assigned as a distinct genus, Segniliparus, because they diverge from rhodococci and mycobacteria in genetic and chemical features. Using high accuracy mass spectrometry, we determined the chemical composition of 65 homologous mycolic acids in two Segniliparus species and separately analyzed the three subclasses to measure relative chain length, number and stereochemistry of unsaturations and cyclopropyl groups within each class. Whereas mycobacterial mycolate subclasses are distinguished from one another by R groups on the meromycolate chain, Segniliparus species synthesize solely non-oxygenated α-mycolates with high levels of cis unsaturation. Unexpectedly Segniliparus α-mycolates diverge into three subclasses based on large differences in carbon chain length with one bacterial culture producing mycolates that range from C58 to C100. Both the overall chain length (C100) and the chain length diversity (C42) are larger than previously seen for mycolic acid-producing organisms and provide direct chemical evidence for assignment of Segniliparus as a distinct genus. Yet, electron microscopy shows that the long and diverse mycolates pack into a typical appearing membrane. Therefore, these new and unexpected extremes of mycolic acid chemical structure raise questions about the modes of mycolic acid packing and folding into a membrane
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