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We have improved the diamond nanoparticle seeding approach for chemical vapor deposition diamond growth in a novel process that consists of embedding the nanoparticles into a polymer matrix. We used a thin film of polyvinyl alcohol (PVA) doped with nanoparticles, which burns away during the initial stages of growth, leaving a stable distribution of nanoparticles on the substrate to initiate growth. The study shows that by varying the initial concentration of nanoparticles in the polymer preparation, it is possible to control the density of nanoparticles on the surface, over a wide range of densities. In some experimental conditions, the high densities of diamond seeding values obtained compare well with the highest values reported by the state-of-the-art. Moreover, the technique also opens up the route to very large area seeding, and this onto most types of substrates. In situ x-ray photoelectron spectroscopy (XPS) analyses showed that after pyrolysis of the polymer under H2 plasma, no significant residual carbon from the polymer was observed. Also, in the case of growth on silicon substrates, no silicon carbide was observed at the surface, showing that no reaction takes place between the polymer and the silicon surface itself. Finally, XPS also demonstrated that the polymer has not modified significantly the surface of the diamond nanoparticles after its pyrolysis. This approach improves the reproducibility of diamond nanoparticle seeding on flat surfaces and is more versatile as it may be applied to complex three-dimensional structures or cavities. [ABSTRACT FROM AUTHOR]

Presents information relating to the development of the bias enhanced nucleation (BEN) step in connection with the case of the synthesis of diamond films by the microwave plasma assisted chemical vapor deposition technique (MPCVD). Occurrence of treatment; What the scratching pretreatment leads to; Conducing of the different observations.

Porous diamond foam exhibiting a three-dimensional structure was synthesized by applying prolonged Bias Enhanced Nucleation on iridium buffer layers. The Raman spectrum of this material recorded at 325 nm looks very close to the signature obtained for detonation nanodiamonds. HRTEM investigations well confirm the presence of diamond crystals with nanometric size between 2 and 6 nm. All these diamond nanocrystals form a three-dimensional structure very different from ultrananocrystalline diamond (UNCD) generally embedded in a graphitic matrix. According to its high specific surface area, such a 3D material may have promising applications for sensors. [ABSTRACT FROM AUTHOR]

Abstract: Topography and chemical evolutions of the iridium surface in the successive steps of bias-enhanced nucleation and growth were investigated using scanning electron microscopy (SEM), atomic force microscopy (AFM), and nano-Auger analyses. This sequential approach, which was performed in localized areas at the nanoscale, provides three new experimental and complementary concepts that can enhance the knowledge of nucleation pathways on iridium. First, SEM imaging at low-acceleration voltage enables the detection of diamond nuclei or stable precursors after the BEN step. Second, domains consist of iridium furrows that are covered by an amorphous carbon overlayer, with a thickness of 6.8nm, according to AFM and X-ray photoemission spectroscopy data. Third, SEM observations also suggest a close relationship between furrows created under ion bombardment and domains in our study conditions. These results prompted us to propose a scheme that describes the topography and surface chemistry of domains. [Copyright &y& Elsevier]

Abstract: The present study well emphasises the role of the bias voltage on the deuterium diffusion in boron doped diamond films . A bias voltage applied between the deuterium microwave plasma and the diamond surface is required to initiate deuterium diffusion. Increasing effective diffusion coefficients are obtained from the SIMS profiles for bias voltages up to . Then, for bias voltages higher than , the etching of diamond film becomes dominant. [Copyright &y& Elsevier]

Abstract: The synthesis of diamond films with extreme insulating properties is of great interest for most diamond film applications in nanoelectronics. SOD (Silicon-On-Diamond) is a promising alternative to standard SOI (Silicon-On-Insulator) because of the high heat-spreading capability of diamond material. Current Fully Depleted MOS processing technologies require a thickness of the dielectric buried layer of 150nm. Synthesis of polycrystalline diamond films is already well documented. Nonetheless, the difficulties here are to keep their high thermal conductivity and their high electrical resistivity in spite of the reduction of the diamond layer thickness. This study aims at the fine control of both the nucleation density and the growth process to enable the fabrication of optimized fully covered diamond films as thin as possible. A mathematical model describing the coalescence was used to determine the surface coverage of the diamond film according to the linear growth of the diamond nanocrystals for different nucleation densities. The model gives information on the nucleation density needed to obtain a covering diamond film within ultrathin diamond layer thickness. To corroborate the coalescence model, diamond layers with different surface coverages were characterized. Our work led to ultrathin diamond layers (thickness below 140nm) exhibiting electrical resistivities above 2×1013 Ωcm. [Copyright &y& Elsevier]

Abstract: Diamond nucleation onto diamond-free substrates remains a major challenge for most diamond films applications. In order to quickly form a continuous film across a given surface, several pre-treatments of the substrate have been developed to increase the nucleation density. Amongst those, Bias Enhanced Nucleation (BEN) has been used intensively for many applications, including for instance the synthesis of ultra-thin diamond films, heteroepitaxial diamond films, or nanodiamond films. The determination of the nucleation kinetics during the BEN pretreatment is particularly relevant in order to obtain fundamental informations about plasma/surface interactions and associated nucleation mechanisms. Besides, it is a key challenge to optimise the BEN step for specific applications, such as epitaxy or high nucleation density. The sequential approach which consists of interrupting the process at different time intervals for nucleation density measurement is time consuming and not accurate enough. We propose a real time investigation of diamond nucleation by laser scattering applied to the Bias Enhanced Nucleation (BEN) pre-treatment on silicon carbide. The Microwave Plasma Chemical Vapour Deposition (MPCVD) reactor was equipped with a laser reflectometry system associated with a lock-in laser intensity measurement. In parallel, a kinetics model of nucleation was drawn based on light diffusion of diamond nanoparticles according to their size and density. The modelling results were compared to the experimental data, and characteristic kinetic parameters were worked out for diamond nucleation on silicon carbide. In this study we demonstrated that using a model based on nanoparticles laser scattering it is possible to determine in real time the kinetics of diamond nucleation. [Copyright &y& Elsevier]

Abstract: Diamond exhibits several attractive properties for bio-sensing applications. In particular its high bio inertness, high electrochemical stability, and optical transparency provide diamond with high interests for neural activity study. The purpose of this study is the realisation of microelectrodes arrays (MEA) in diamond for neurons slices study. Due to a cellular lysis on the edge of the tissue slices studied, electrodes have to be at least 60 μm in height even though the electrode surface has to be minimised in order to achieve good signal noise rate. Silicon MEA with metal contacts were realised using (Deep Reactive Ion Etching) DRIE and coated with Nanocrystaline Diamond (NCD) using (Bias Enhanced Nucleation) BEN technique. We focus the study on the understanding of the BEN nucleation process on such high aspect ratio electrodes. Several parameters such as slope of the substrate, conductivity and chemical nature of the substrate were studied in order to enable selective nucleation necessary to fabricate diamond MEAs. The study leads to the optimised development of a processing route enabling the selective coating of the active tips of high aspect ratio MEAs without altering the electrical insulation between probes. [Copyright &y& Elsevier]

Abstract: Detonation nanodiamond dispersed on silicon surfaces underwent different H2 MPCVD exposures. The induced changes at the surface have been characterized in situ by XPS and XEELS. Then, a short CH4/H2 growth step was applied. This sequential study revealed an excellent stability of detonation nanodiamond. The sp3 etching rate is insufficient to remove nanodiamond even under intense H2 plasma. The H2 exposure could be successfully used to remove C–C sp2 carbon without altering sp3 seeds. Moreover, the formation of silicon carbide observed after the hydrogen treatment is thought to be helpful to enhance the adhesion of nanodiamond particles on the substrate. [Copyright &y& Elsevier]

Abstract: The nature of hydrogen and carbon bonding configuration formed onto 3C–SiC(100) surfaces by the diamond bias enhanced nucleation process consisting of stabilization and biasing stages were investigated by high resolution electron energy loss spectroscopy and high resolution X-ray photoelectron spectroscopy. During the stabilization stage a sp3-CH x bonded carbonaceous mono-layer is formed onto a hydrogenated 3C–SiC(100)–C–H terminated surfaces. After the biasing stage a hydrogenated nano-diamond film is formed. It was determined that hydrogen is strongly bonded to these nano-diamond surfaces and boundaries in sp3-C–H and sp2-C–H mono-hydride configuration. In addition, CH x (x >1) weakly bonded surface or sub-surface species were detected. Regions which are not fully covered by the nano-diamond film expose the SiC surface covered with a very thin carbonaceous layer. [Copyright &y& Elsevier]

Abstract: The mechanisms involved in the diamond nucleation on 3C–SiC surfaces have been investigated using a sequential in situ approach using electron spectroscopies (XPS, XAES and ELS). Moreover, diamond crystals have been studied by HRSEM. The in situ nucleation treatment allows a high diamond nucleation density close to 4×1010 cm− 2. During the in situ enhanced nucleation treatment under plasma, a negative bias was applied to the sample. The formation of an amorphous carbon phase and the roughening of the 3C–SiC surface have been observed. The part of these competing mechanisms in diamond nucleation is discussed. [Copyright &y& Elsevier]

Surface morphology and surface chemistry of epitaxial Ir/SrTiO 3 /Si(001) pseudo-substrates were systematically characterized by Field Emission Scanning Electron Microscopy (FE-SEM), Atomic Force Microscopy (AFM) and X-ray Photoelectron Spectroscopy (XPS) before and after the Bias Enhanced Nucleation (BEN) of diamond. Based on these characterizations, an ellipsometric model was built taking into account both the roughening of the iridium surface and the formation of domains occurring during the BEN process. Sequential spectroscopic ellipsometry (SE) characterizations allowed estimating the roughening of the iridium surface, the thickness of the amorphous carbon layer and the coverage ratio of domains. By annealing the sample in air after BEN, domains were successfully removed without changing the iridium surface morphology. From these analyses, we demonstrate that SE is enough sensitive and discriminative to monitor both the formation of domains and the roughening of iridium surface, distinctly. SE can then be viewed as a powerful in situ tool of critical importance to study, monitor and finally enhance the diamond nucleation and growth on iridium for various advanced applications. Unlabelled Image • The analysis by ellipsometry proved its sensitivity to the formation of domains. • Sequential analysis by FE-SEM, AFM and XPS allows to build the most relevant ellipsometric model keeping a physical meaning. • This study opens the way to in situ monitoring of early stages of heteroepitaxial diamond growth during BEN. [ABSTRACT FROM AUTHOR]

A contrast clearly correlated with the linear defect network into boron-doped diamond epilayers was evidenced by FE-SEM observations performed at 20 kV. According to this study, this effect is dependent on the incident electron energy, the boron concentration, the thickness of the epilayer and the surface termination. These contrasts are confirmed to correspond to dislocations by revealing the etch pits using a H 2 /O 2 plasma and by cathodoluminescence analyses. Boron impurities seem to play a major role in the contrast formation. • Reports on a fast, non-destructive and competitive method to analyze linear defect distributions in CVD boron doped diamond epilayers, especially dislocations. • The black contrast observed by FE-SEM at 20 kV on boron-doped diamond epilayers is correlated with dislocations as confirmed by H 2 /O 2 plasma etching and cathodoluminescence mapping. • The effects of the incident electron energy, the boron concentration, the thickness and the surface termination of the epilayer were investigated. [ABSTRACT FROM AUTHOR]

The present study deals with the interaction of C-terminated c(2×2) and Si-rich 3×2 3C-SiC (100) reconstructed surfaces with a microwave plasma chemical vapor deposition used for diamond growth. Pure hydrogen and hydrogen/methane exposures have been carried out. Their effects on the atomic ordering and the stoichiometry within the first planes have been studied in situ using low energy electron diffraction and electron spectroscopies: x-ray photoelectron spectroscopy, x-ray Auger electron spectroscopy, and ultraviolet photoelectron spectroscopy. 5 min plasma exposures result in a lost of the initial reconstructions, a postplasma oxygen contamination, and strong modifications of the stoichiometry within the first planes. Indeed, the stability of well defined 3C-SiC surfaces depends strongly on their termination: C-terminated surface exhibits a high inertia while the Si-rich surface undergoes partial etching. The three first silicon atomic planes involved in the 3×2 reconstruction are removed upon pure hydrogen plasma while a monolayer is preserved after hydrogen/methane exposure. [ABSTRACT FROM AUTHOR]

Abstract We report on an innovative method to synthesize monodispersed diamond core-shells stable in colloidal aqueous suspensions. Starting with an electrostatic seeding of silica particles by detonation nanodiamonds, carefully driven in terms of charge and proportion, we are able to initiate the growth of a carbon coating all around the seeded silica particles in a plasma MPCVD reactor dedicated to powder treatments. The crystalline structure of the carbon coating can be tuned by changing the MPCVD conditions: from nanocrystalline diamond for low methane content to graphite nanoflakes for high methane content. These materials are characterized by FE-SEM, HR-TEM, FTIR and Raman spectroscopy. Preliminary photoluminescence (PL) data are also provided. A chemical post-treatment of the core-shell particles is applied to obtain colloidal stability in neutral aqueous suspensions. The monodispersity and the colloidal stability are assessed using DLS and Zeta measurements. After the removal of the silica core, stable suspensions of diamond hollow spheres are obtained. This new class of diamond-based material may find promising applications in various fields, such as nanomedicine toward a versatile nanotool for drug delivery or biolabeling, catalysis thanks to its controllable porosity and carbon surface chemistry or photonics as an elemental block toward bottom-up ordered diamond structures. Graphical abstract Unlabelled Image Highlights • Synthesis of spherical and monodispersed diamond core-shells • Hollow spheres stabilized in colloidal aqueous suspensions • Crystalline structure of the carbon coating tunable from nanocrystalline diamond to graphitic nanoflakes • Combination of characterization techniques to investigate the core shells [ABSTRACT FROM AUTHOR]

The present paper aims to provide a better insight to the dielectric charging phenomena of nano-crystalline diamond (NCD) films that are used in RF MEMS capacitive switches. The electrical properties of NCD films of various thicknesses are investigated with the aid of metal-insulator-metal (MIM) capacitors. The dominant conduction mechanisms have been identified by obtaining current-voltage characteristics in the temperature range from 300 K to 400 K and dielectric charging phenomena have been investigated by using thermally stimulated depolarization currents (TSDC) technique. The experimental results indicate a thermally activated conductivity for low electric field intensities while Hill-type conduction takes place for field intensities > 130 kV/cm. The conductivity as well as the defect density seems to increase with film thickness. Enhanced dielectric charging phenomena have been observed on thicker films and the injected charges are found to be trapped through the material's volume. These results indicate that thinner NCD films seem to be more promising for RF MEMS capacitive switches. [ABSTRACT FROM AUTHOR]

Résumé Introduction La thrombopénie est associée au sepsis et à la mortalité en milieu de réanimation pédiatrique. Le but de notre travail était de rechercher une association entre la thrombopénie et la nature des germes infectants afin de mieux guider le choix de l’antibiothérapie probabiliste chez l’enfant en réanimation. Matériel et méthodes Il s’est agi d’une étude prospective descriptive, incluant tous les nouveau-nés, nourrissons et enfants admis dans une unité de réanimation chirurgicale pédiatrique pendant une période d’1 an. Parmi eux, les patients ayant développé une infection (germe responsable et profil de résistance aux antibiotiques) ou une thrombopénie (nombre de plaquettes inférieur à 100 000/mm 3 ) au cours de l’hospitalisation ont été identifiés. Résultats Cent quatre-vingt-dix-sept patients ont été inclus (28,9 % de nouveau-nés). Quatre-vingt-dix enfants ont développé 100 épisodes infectieux durant la période d’étude. Trente-quatre épisodes de thrombopénie ont été observés chez 30 enfants. Une thrombopénie n’a été observée que chez les enfants considérés comme infectés ( p < 0,001). La thrombopénie était associée à l’infection par bacilles à Gram négatif ( p = 0,001), due au genre Klebsiella ( p = 0,001). Il existait une tendance à l’association entre germes sécréteurs de β-lactamases à spectre élargi et thrombopénie ( p = 0,07). Conclusion En raison de la proportion assez importante de bacilles à Gram négatif présentant un profil de résistance étendue, une antibiothérapie probabiliste à large spectre, associant une carbapénème et un aminoside, pourrait être indiquée chez les enfants présentant un syndrome infectieux associé à une thrombopénie en milieu de réanimation. Summary Background Thrombopenia is correlated with sepsis and mortality in pediatric intensive care units. The purpose of this study was to find an association between thrombopenia and the microorganism type to guide the choice of empiric antibiotic therapy in infected critically ill children. Materials and methods We conducted a prospective descriptive study, including all newborns, infants, and children admitted to a pediatric surgical intensive care unit from 1st January to 31st December 2009. We identified patients who developed an infection and/or thrombopenia (platelet count less than 100,000/mm 3 ) during hospitalization. Results One hundred ninety-seven patients were included (57 newborns, 41 infants, 99 children). Ninety patients developed 100 infectious episodes during the study period. Of the 57 newborns enrolled in the study, 31 (54%) developed 37 infections. Seventy-six microorganisms (55 Gram-negative bacilli [GNB], 17 Gram-positive cocci, two Gram-negative cocci, two fungal pathogens) were identified during 65 infectious episodes in 55 patients. Thirty-four episodes of thrombopenia were observed in 30 patients. Thrombopenia was observed only in infected patients ( P < 0.001). Thrombopenia was associated with infections caused by GNB (26/28 vs 20/37, P = 0.001) and by Klebsiella (16/28 vs 6/37, P = 0.001) and may be associated with infections caused by GNB producing extended-spectrum beta-lactamases ( P = 0.07). Gram-positive cocci infections were correlated to the non-occurrence of thrombopenia ( P = 0.02). Postoperative peritonitis was also significantly associated with thrombopenia ( P = 0.03). The mortality rate in our patients was 12.7% (22.8% in neonates). There was an association between thrombopenia and death in univariate analysis (11/25 vs 19/172, P < 0.001). Multivariate logistic regression analysis did not confirm thrombopenia as an independent predictive factor of mortality in children. Conclusion Because of the relatively high proportion of resistant GNB, an empiric antibiotic therapy combining a carbapenem and an aminoglycoside may be indicated in infected critically ill children developing thrombopenia. [ABSTRACT FROM AUTHOR]

Abstract: Nanodiamond seeding toward CVD (chemical vapor deposition) synthesis of diamond layers has received growing interest during the last decade. Several methods are now available to disperse highly dense and compact nanodiamond deposits on a substrate, enabling the growth of ultrathin diamond layers with thickness below 70nm. While these approaches are extremely efficient to deposit nanodiamonds on plane substrates, even on large areas, a limitation still persists for 3D structured substrates. Here, we report on a technique to disperse nanodiamonds on nanometric patterns, allowing the manufacture of diamond nanostructures by a bottom–up approach, such as diamond coated silicon nanodevices or high aspect ratio diamond tips. [Copyright &y& Elsevier]

Abstract: Electrochemical activity, morphology and surface electrical conductivity of Boron-Doped Polycrystalline Diamond films prepared by MPCVD have been investigated. Heterogeneous apparent rate constants of three different redox systems, [Fe(CN)6]3−/4−, [IrCl6]2−/3− and [Ru(NH3)6]3+/2+ have been measured by both Cyclic Voltammetry and Electrochemical Impedance Spectroscopy on<100>textured films with a predominance of (111) faces: first measurements have been done with [Fe(CN)6]3−/4− only on as grown samples, and secondly after a mild electrochemical pretreatment the three redox systems have been investigated. “As-grown” samples showed a moderate average activity which was related to the presence of a minority of electronically conducting areas among insulating zones. Electrochemical treatment in neutral conditions substantially increased the activity and heterogeneous apparent rate constants k app for the three couples were measured in the range of 10−2 cms−1 with a good stability in time. Current-sensing AFM images performed ex situ showed that the electrochemically pre-treated material presented a high superficial conductivity whereas the grown sample showed major area of low conductivity. [Copyright &y& Elsevier]

Abstract: In this study, Silicon-On-Diamond (SOD) micro-structures have been fabricated using either Smart Cut™ or bonded and Etched-Back Silicon On Insulator (BESOI) technology. Thanks to the development of an innovative smoothening process, polycrystalline diamond layers (C*) can be integrated as a buried oxide layer offering new opportunities in terms of thermal management. We describe different technological process flow investigations leading to SOD by bonding C* layer in the stack. As starting material we used poly-crystalline thin diamond films in the 200nm to 7000nm range of thickness. The C* is deposited by Chemical Vapour Deposition assisted by Microwave Plasma (MPCVD) onto various 50mm wafers such as Si, SOI and polycrystalline silicon carbide (pSiC). As the roughness of the diamond layer is not directly compatible with a wafer bonding integration, an innovative smoothening process in 3 steps has been developed and named “DPE” for Deposition, Planarization and Etching. Using the DPE process, the roughness of 5µm thick diamond layer could be reduced from 50 to 3nm RMS and down to 1.5nm RMS for a thin 200nm layer. In order to demonstrate the feasibility of a GaN on SOD micro-structure design for HEMT applications, layer transfers have been carried out by a bonding and thinning process from C*/Si bulk using oxide bonding layers. From thermal spreading efficiency consideration, new processes of fabrication of SOD/poly-SiC substrate are in progress involving BESOI or Si Smart Cut™ technologies and poly-Si bonding layer starting from C*/poly-SiC. Pure SOD substrate were also fabricated by using C*/SOI and poly-Si bonding layer in a BESOI technology. A thin active silicon layer (70nm) of 50mm diameter onto a 140nm thick diamond BOX layer has been transferred on 200mm diameter Si substrate for future MOSFET''s devices demonstrations. Significant progress has been done in diamond layer integration by wafer bonding. [Copyright &y& Elsevier]

Abstract: In this paper, Silicon on Diamond (SOD) substrates were fabricated using the direct bonding process in two different technologies: the BESOI (Bonded and Etched-back SOI) and the Smart-Cut™ process. The polycrystalline diamond (C∗) film deposited by Chemical Vapor Deposition assisted by Microwave Plasma (MPCVD) was planarized by an innovative process which induces a significant decrease of the diamond surface roughness (1.2nm for the 200nm diamond layer). The planarization method as well as the entire SOD substrate process by the BESOI or the Smart-Cut™ technology are described in the paper. Cross sectional high-resolution transmission microscopy reveals the good quality of the future silicon channel on top of the thin diamond layer. [Copyright &y& Elsevier]

Abstract: In this work, 0.30μm thick LiNbO3 layers have been deposited by sputtering on nanocrystalline diamond/Si and platinised Si substrates. The films were then analyzed in terms of their structural and optical properties. Crystalline orientations along the (012), (104) and (110) axes have been detected after thermal treatment at 500°C in air. The films were near-stoichiometric and did not reveal strong losses or diffusion in lithium during deposition or after thermal annealing. Pronounced decrease of the roughness on top of the LiNbO3 layer and at the interface between LiNbO3 and diamond was also observed after annealing, compared to the bare nanocrystalline diamond on Si substrate. Furthermore, ellipsometry analysis showed a better density and a reduced thickness of the surface layer after post-deposition annealing. The dielectric constant and losses have been measured to 50 and less than 3.5%, respectively, for metal/insulator/metal structures with 0.30μm thick LiNbO3 layer. The piezoelectric coefficient d 33 was found to be 7.1pm/V. Finally, we succeeded in switching local domain under various positive and negative voltages. [Copyright &y& Elsevier]

The growth of large-area diamond films with low dislocation density is a landmark in the fabrication of diamond-based power electronic devices or high-energy particle detectors. Here, we report the development of a growth strategy based on the use of micrometric laser-pierced hole arrays to reduce dislocation densities in heteroepitaxial chemical vapor deposition diamond. We show that, under optimal growth conditions, this strategy leads to a reduction in dislocation density by two orders of magnitude to reach an average value of 6 × 105 cm−2 in the region where lateral growth occurred, which is equivalent to that typically measured for commercial type Ib single crystal diamonds. [ABSTRACT FROM AUTHOR]

Two 3C-SiC(100) reconstructed surfaces have been exposed to bias enhanced nucleation (BEN) treatments performed in a microwave plasma chemical vapor deposition reactor. For both BEN steps, a significant enhancement of the diamond nucleation density has been observed on the initial C-terminated surface compared to the Si-rich surface. Samples have been characterized by in situ surface analysis, namely, x-ray photoelectron spectroscopy and x-ray Auger electron spectroscopy, and by field emission gun scanning electron microscopy. [ABSTRACT FROM AUTHOR]

Introduction: Suicide mortality is 12 times higher in psychotic patients compared to the general population. Identifying characteristic of suicidal patients among this group might help in preventing such behavior. Objectives: To assess the predictors of suicidal risk in patients hospitalized due to acute psychosis. Methods: One hundred and fifty patients (age 18 - 60 years) admitted with acute psychotic features were recruited. Patients were evaluated clinically by The Arabic version of Mini International Neuropsychiatric Interview (M.I.N.I.). Suicidal ideation was assessed using the Scale for Suicide Ideation (SSI). Results: Forty four out of 150 patients (29.33%) reported having current and/or previous history of suicidal ideation. Patients with major depression showed the highest suicidal tendencies followed by delusional disorder then bipolar disorder, psychosis related to substance abuse and schizophrenia. The more severe the psychotic symptoms, the more suicidal tendencies shown by patients. Predictors for suicidal ideations included diagnostic category, severity of psychotic features, unemployement and younger age Conclusions: Patients with psychosis that require admission to the hospital carry a high risk of suicidal ideation and behavior. Factors like unemployment, young age and psychiatric diagnosis and severity of psychosis could be predicting factors. [ABSTRACT FROM AUTHOR]

Introduction Les neurotrophines (NTs) et la neurotensine (NTS), neuropeptides capables de moduler la réponse immune et/ou la survie lymphocytaire et plasmocytaire, mettent en jeu les mêmes boucles autocrines de survie (Akt et Erk). Parmi les traitements de fond de la polyarthrite rhumatoïde (PR), le methotrexate (MTX) et le rituximab (RTX) régulent l’inflammation par modulation cytokinique et déplétion lymphocytaire. Environ 30 % des patients traités sont cependant en échec thérapeutique. L’objectif de cette étude est de rechercher l’implication de la NT BDNF et de la NTS dans la survie et la résistance à l’apoptose lymphocytaire après traitement par MTX et RTX. Résultats L’étude in vitro a été réalisée sur une lignée cellulaire de lymphome B mature EBV négatif (BL41). La modulation de la prolifération et de l’apoptose via l’ajout de BDNF et de NTS exogènes ainsi que le blocage pharmacologique de leurs récepteurs spécifiques ont été effectuées en conditions basales de culture et de déprivation sérique après traitements par MTX et RTX. L’étude des voies de signalisation Akt, Erk et P38 a été réalisée par Western Blot. L’étude in vivo a été effectuée sur n = 21 patients adultes atteints de PR (critères ACR 1987 remplis) traités par MTX et/ou RTX et n = 10 témoins sains appariés par âge et sexe. L’activité de la maladie a été mesurée selon le DAS28 VS Après Ficoll ® , les sérums, LB et LT ont été extraits par immunosélection négative. Les études ont été menées par tests Elisa pour le dosage sérique de BDNF et NTS, qPCR pour l’expression transcriptionnelle de BDNF, NTSR1 et 2, et Sortiline pour les lymphocytes non B ; par cytométrie de flux pour TrkB, Sortiline et NTSR2 pour les lymphocytes B. L’analyse statistique a été effectuée sur des expériences indépendantes via StatView. In vivo, les concentrations sériques de BDNF et NTS augmentaient significativement chez les patients PR par rapport aux témoins. Elles avaient tendance à croître avec l’activité de la maladie et à distance du traitement par RTX. Le RTX réduisait les taux sériques de BDNF et NTS, mais sans recouvrer ceux des témoins. Parallèlement, l’expression lymphocytaire B et T de leurs récepteurs était modifiée : l’étude transcriptionnelle des récepteurs de la neurotensine au niveau lymphocytaire T mettait en évidence une extinction de transcription de NTSR1 chez les patients PR ( p < 0,05). A contrario, plus la PR était active, plus NTSR2 était surexprimée ( p < 0,05). Une augmentation significative de la transcription de la Sortiline s’observait aussi. Au niveau lymphocytaire B, TrkB s’exprimait exclusivement chez les patients PR ( p < 0,05) et la Sortiline tant chez les patients que chez les témoins, avec tendance à augmenter avant retraitement par RTX. In vitro, en condition de stress sérique, BDNF et NTS accroissaient la survie cellulaire BL41 par les voies Erk et Akt, inhibées par le MTX et le RTX. La NTS exogène réduisait l’apoptose qui était induite par le RTX sur la lignée BL41 et potentialisée par le blocage du récepteur NTSR1 (Meclinertant ® ). Conclusion En conclusion, cette étude met en évidence une augmentation sérique du BDNF et de la NTS au cours de la PR, en particulier active. Le traitement par RTX permet une réduction de ces taux plasmatiques. L’ensemble des résultats in vivo et in vitro effectués sur cellules B et T laissent ainsi percevoir l’implication du BDNF et de la NTS dans la résistance thérapeutique au RTX via l’expression membranaire de TrkB. Le profil d’expression lymphocytaire T des récepteurs à la NTS évoque également l’implication de cette dernière dans le maintien d’une réponse immune pathologique. [ABSTRACT FROM AUTHOR]

A single crystal diamond large area thin membrane was assembled as a p-doped/Intrinsic/Metal (PIM) structure and used in a betavoltaic configuration. When tested with a 20 keV electron beam from a high resolution scanning electron microscope, we measured an open circuit voltage (Voc) of 1.85V, a charge collection efficiency (CCE) of 98%, a fill-factor of 80%, and a total conversion efficiency of 9.4%. These parameters are inherently linked to the diamond membrane PIM structure that allows full device depletion even at 0V and are among the highest reported up to now for any other material tested for betavoltaic devices. It enables to drive a high short-circuit current Isc up to 7.12 lA, to reach a maximum power Pmax of 10.48 lW, a remarkable value demonstrating the high-benefit of diamond for the realization of long-life radioisotope based micro-batteries. [ABSTRACT FROM AUTHOR]

The present study provides a multi-scale investigation of the crystalline quality and the structural defects present in heteroepitaxial diamond films grown on iridium/SrTiO 3 (001) substrates by microwave plasma assisted chemical vapor deposition. X-ray diffraction, Raman spectroscopy and low temperature cathodoluminescence are combined to accurately characterize the mosaicity, the density of dislocations and the residual strain within the films. X-ray diffraction and Raman results confirm a structural quality at the state-of-the-art according to the epitaxial relationship 〈100〉diamond(001) // 〈100〉iridium(001) // 〈100〉SrTiO 3 (001). In addition, Raman and cathodoluminescence observations on cross-sections reveal the presence of local strain. [ABSTRACT FROM AUTHOR]

We demonstrate a diamond photonics platform with integrated suspended waveguide-cavity structures and two dimensional photonic crystal (PhC) cavities. PhC cavities with quality factors exceeding 2800 have been fabricated using a top-down approach from thin nanocrystalline diamond films. The developed technological process allows one to access these cavities in a fully planar geometry, including light injection and collection from the outside using lensed-fibers. This diamond platform opens the road to large scale fabrication of photonics devices including optical sensor chips. [ABSTRACT FROM AUTHOR]

Abstract: Nanodiamonds (NDs) emerge as excellent candidates for biological applications but their functionalization is still an issue. By analogy with hydrogenated diamond layers, an efficient and homogeneous covalent functionalization can be achieved on hydrogenated NDs. Here is reported an efficient new approach to hydrogenate NDs by reducing all various oxygenated groups into C–H terminations. The hydrogenation treatment is performed by exposing the nanoparticles to microwave hydrogen plasma in the gas phase. The hydrogenation of the nanoparticles has been carefully characterized by FTIR and XPS analysis revealing strong modification and homogenization of their entire surface. To validate this hydrogen treatment, functionalization of the NDs has been conducted by using diazonium reactions. An efficient grafting was observed for the hydrogenated NDs compared to the as-received ones. [Copyright &y& Elsevier]

Abstract: Hot filament and microwave plasma CVD micro- nanocrystalline diamond films are analysed by visible and ultra-violet excitation source Raman spectroscopy. The sample grain size varies from 20 nm to 2 μm. The hydrogen concentration in samples is measured by SIMS and compared to the grain size, and to the ratio of sp2 carbon bonds determined by Raman spectroscopy from the 1332 cm−1 diamond peak and the sp2 1550 cm−1 G band. Hydrogen concentration appears to be proportional to the sp2 bonds ratio. The 3000 cm−1 CH x stretching mode band intensity observed on the Raman spectra is decreasing with the G band intensity. Thermal annealing modifies the sp2 phase structure and concentration, as hydrogen outdiffuses. [Copyright &y& Elsevier]

Advanced characterizations with combined analytical tools were carried out at the different stages of diamond heteroepitaxy on Ir/STO/Si (001) substrates. HRTEM and STEM-EELS revealed the presence of epitaxial nanometric diamond crystals after bias enhanced nucleation. UV Raman allowed estimating the diamond film quality and its strain at the early stages of heteroepitaxial growth. The crystalline structure and the strain within thick heteroepitaxial films were determined by XRD and CL investigations. A CL study of the cross-section provided the mapping of the dislocation network along the growth direction. Measurements performed on lateral Schottky diodes fabricated on a thick diamond film showed an excellent reproducibility on the substrate with a Schottky barrier height in good agreement with those obtained on homoepitaxial layers. Unlabelled Image • Characterizations performed at different stages of heteroepitaxy to relate the electrical properties to the structural ones. • After BEN and without CVD growth, diamond nuclei are evidenced by HRTEM and STEM-EELS • Measurements on lateral Schottky diodes showed an excellent reproducibility on the substrate • Schottky barrier height in good agreement with those obtained on homoepitaxial layers • Heteroepitaxial diamond films show similar boron incorporation efficiency as homoepitaxial ones. [ABSTRACT FROM AUTHOR]

Introduction Plusieurs protocoles de sédation ont été proposés pour les enfants programmés pour IRM dans le but d’assurer une immobilité du patient et de diminuer l’incidence des effets indésirables en particulier respiratoires. Le but de notre étude était de comparer la Dexmédétomidine au Propofol chez les enfants proposés pour IRM sous sédation. Matériel et méthodes Après l’accord du comité local d’éthique et le consentement éclairé des parents, nous avons mené une étude prospective randomisée, incluant les enfants âgés de 6 mois à 10 ans et proposés pour un examen IRM sous sédation. Prémédication au Midazolam intranasal 0,3 mg/kg. Les patients ont été randomisés en deux groupes : – Groupe D (GD) : les enfants ont reçu une dose de charge de 2 μg/kg sur 10 min (en salle de préinduction) d’une solution de Dexmédétomidine diluée à 4 μg/mL, immédiatement relayée par une perfusion continue de la même solution à la dose de 1 μg/kg/h (à l’entrée en salle d’IRM) jusqu’à la fin de l’examen ; – Groupe P (GP) : les patients ont reçu du Propofol : 4 mg/kg à l’induction, puis 6 mg/kg/h comme dose d’entretien jusqu’à la fin de l’examen. Tous les enfants ont été gardés en ventilation spontanée à travers un masque facial délivrant 50 % O 2 , 50 % N 2 O. En cas d’apnée prolongée avec désaturation, une ventilation mécanique transitoire a été démarrée. En cas de mouvement au cours de l’IRM, le malade reçoit un bolus de Propofol de 1 mg/kg. À la fin de l’examen IRM, les patients étaient transférés en salle de réveil. La sortie du centre était autorisée lorsque le score d’Aldrete était ≥ 9 et score de Ramsay < 3. Notre critère de jugement principal était la survenue de mouvements per anesthésiques, nécessitant l’administration d’un bolus de Propofol. Les critères de jugement secondaire étaient les incidents respiratoires (apnée, recours à la ventilation mécanique), hémodynamiques (bradycardie, hypotension), la durée de l’occupation de la salle d’IRM avant le démarrage de la procédure, le délai de réveil (délai d’ouverture des yeux), de sortie du sortie du centre et le coût des produits utilisés. Nous avons utilisé le test de Khi 2 pour comparer les variables qualitatives et le test t de Student pour comparer les variables quantitatives. p < 0,05 a été considéré comme significatif. Résultats Quatre-vingt-trois patients ont été inclus dans l’étude, un patient du groupe P a été secondairement exclu en raison d’un bronchospasme sévère ayant nécessité l’interruption de l’examen. Les données de 82 patients ont été analysées (GP = GD = 41). Les paramètres démographiques et la durée d’IRM étaient comparables entre les deux groupes. Un seul épisode de bradycardie sans retentissement hémodynamique a été observé chez un enfant du GD ( Tableau 1 ). Discussion La Dexmédétomidine procure une profondeur d’anesthésie comparable à celle du Propofol, tout en diminuant le risque d’évènements respiratoires indésirables chez les enfants proposés pour IRM sous sédation. [ABSTRACT FROM AUTHOR]