Design optimization of RF lines in vacuum environment for the MITICA experiment

This contribution regards the Radio Frequency (RF) transmission line of the Megavolt ITER Injector and Concept Advancement (MITICA) experiment. The original design considered copper coaxial lines of 1″ 5/8, but thermal simulations under operating conditions showed maximum temperatures of the lines at regime not compatible with the prescription of the component manufacturer. Hence, an optimization of the design was necessary. Enhancing thermal radiation and increasing the conductor size were considered for design optimization: thermal analyses were carried out to calculate the temperature of MITICA RF lines during operation, as a function of the emissivity value and of other geometrical parameters. Five coating products to increase the conductor surface emissivity were tested, measuring the outgassing behavior of the selected products and the obtained emissivity values

Effect of Mo content on the microstructure and mechanical properties of CoCrFeNiMox HEA coatings deposited by high power impulse magnetron sputtering

In this work, CoCrFeNiMox high entropy alloy (HEA) films were deposited by High Power Impulse Magnetron Sputtering (HiPIMS) using pure Mo and equiatomic CoCrFeNi targets. The effect of Mo content on the microstructure, residual stress state, and mechanical properties of the films was investigated in the range of 0–20 at.%. All films exhibited a columnar growth morphology and a high density of planar defects. Increasing the Mo content promoted the formation of a fine-grained structure and induced the transformation from a single face-centered cubic (FCC) phase to a mixture of FCC and body-centered cubic (BCC) phases. All produced films displayed a compressive residual stress state regardless of the Mo concentration. In terms of mechanical properties, the hardness of the films increased with increasing Mo content due to solid solution and grain boundary strengthening, along with the formation of a hard BCC phase. On the other hand, the elastic modulus decreased, likely due to the formation of an amorphous phase at higher Mo concentrations

B-cell depletion abrogates immune mediated cytopenia and rejection of cord blood transplantation in Hurler syndrome

Umbilical cord blood is the preferred donor cell source for children with Inherited Metabolic disorders undergoing Hematopoietic Cell Transplant (HCT), and its use has been associated with improved “engrafted survival” and higher donor chimerism compared to other cell sources. However, as in other pediatric cord blood transplants for non-malignant disease, immune-mediated cytopenia and primary graft failure limit its use, and the latter remains the commonest cause of death following cord blood transplant for non-malignant disease. We have previously shown an association between immune-mediated cytopenia and graft failure in inherited metabolic diseases suggesting that both immune-mediated cytopenia and graft failure could be mediated by antibodies from the residual recipient B cells. Since rituximab is effective in depletion of B cells and management of refractory immune-mediated cytopenia following HCT, we have added rituximab to the conditioning regimen. We studied 57 patients in 2 centers who received myeloablative conditioning for cord blood transplant in Hurler syndrome, and report a significant improvement in event-free survival with reduced incidence of graft failure and without any evidence of immune-mediated cytopenia in those patients that had received rituximab

Syndecan-1 promotes the angiogenic phenotype of multiple myeloma endothelial cells

Angiogenesis is considered a hallmark of multiple myeloma (MM) progression. In the present study, we evaluated the morphological and functional features of endothelial cells (ECs) derived from bone marrow (BM) of patients affected by MM (MMECs). We found that MMECs compared with normal BM ECs (BMECs) showed increased expression of syndecan-1. Silencing of syndecan-1 expression by RNA interference technique decreased in vitro EC survival, proliferation and organization in capillary-like structures. In vivo, in severe combined immunodeficient mice, syndecan-1 silencing inhibited MMEC organization into patent vessels. When overexpressed in human umbilical vein ECs and BMECs, syndecan-1 induced in vitro and in vivo angiogenic effects. Flow-cytometric analysis of MMECs silenced for syndecan-1 expression indicated a decreased membrane expression of vascular endothelial growth factor (VEGF) receptor-2 (VEGFR-2). Immunoprecipitation and confocal analysis showed colocalization of VEGFR-2 with syndecan-1. Absence of nuclear translocation of VEGFR-2 in syndecan-1-knockdown cells together with the shift from perinuclear localization to recycling compartments suggest a role of syndecan-1 in modulation of VEGFR-2 localization. This correlated with an in vitro decreased VEGF-induced invasion and motility. These results suggest that syndecan-1 may contribute to the highly angiogenic phenotype of MMECs by promoting EC proliferation, survival and modulating VEGF–VEGFR-2 signalling

Adherence with statins in a real-life setting is better when associated cardiovascular risk factors increase: a cohort study

<p>Abstract</p> <p>Background</p> <p>While the factors for poor adherence for treatment with statins have been highlighted, the impact of their combination on adherence is not clear.</p> <p>Aims</p> <p>To estimate adherence for statins and whether it differs according to the number of cardiovascular risk factors.</p> <p>Methods</p> <p>A cohort study was conducted using data from the main French national health insurance system reimbursement database. Newly treated patients with statins between September 1 and December 31, 2004 were included. Patients were followed up 15 months. The cohort was split into three groups according to their number of additional cardiovascular risk factors that included age and gender, diabetes mellitus and cardiovascular disease (using co-medications as a <it>proxy</it>). Adherence was assessed for each group by using four parameters: <it>(i) </it>proportion of days covered by statins, <it>(ii) </it>regularity of the treatment over time, <it>(iii) </it>persistence, and <it>(iv) </it>the refill delay.</p> <p>Results</p> <p>16,397 newly treated patients were identified. Of these statin users, 21.7% did not have additional cardiovascular risk factors. Thirty-one percent had two cardiovascular risk factors and 47% had at least three risk factors. All the parameters showed a sub-optimal adherence whatever the group: days covered ranged from 56% to 72%, regularity ranged from 23% to 33% and persistence ranged from 44% to 59%, but adherence was better for those with a higher number of cardiovascular risk factors.</p> <p>Conclusions</p> <p>The results confirm that long-term drug treatments are a difficult challenge, particularly in patients at lower risk and invite to the development of therapeutic education.</p

In-house synthesis of CoCrFeNi ingots using an electric furnace

Bulk Multi-Principal Element Alloys (MPEAs) are generally synthesized by casting, a process needing specific equipment. Here, a standard laboratory electric furnace was used to synthesize bulk CoCrFeNi by melting of prealloyed powders followed by natural cooling. The use of prealloyed powders guaranteed atomic-level mixing. In accordance with the literature, the resulting ingot had a face-centered cubic structure. A typical dendritic-interdendritic microstructure was obtained which was explained by partitioning during solidification and grain boundary wetting phenomenon. Post-annealing treatment improved chemical homogeneity without crystallographic phase change. This work shows the feasibility of melt-aided synthesis of CoCrFeNi HEA under static conditions using a conventional laboratory furnace

PdAg/alumina membranes prepared by high power impulse magnetron sputtering for hydrogen separation

The development of hydrogen purification membranes that meet market demands such as high purity, dynamic hydrogen production even at small scale, and reduced costs is still an open question. With this view, the present study aims at developing, for the first time, a method based on high power impulse magnetron sputtering for the deposition of Pd77Ag23 (wt%) films onto porous alumina substrates to achieve composite membranes with high hydrogen permeability and stability. This technique allows the deposition of films also on complex geometries and can be easily scaled up, thus making this technology a potential candidate for preparing high performing membranes. Membranes made by stable and porous alumina supports and metallic, dense and crystalline Pd77Ag23 layers, from 3.5 mm to 17 mm thick, have been prepared and tested. The membranes showed good hydrogen permeability values, showing flux values up to a maximum of 0.62 molH2 m2 s1 at 450 C and DP of 300 kPa. The resistance to hydrogen embrittlement and the chemical inertness to syngas were also demonstrated

Structural, morphological and mechanical characterization of Mo sputtered coatings

In this work, the intrinsic properties of molybdenum films deposited by DC magnetron sputtering (DCMS) on titanium substrates have been investigated, as a function of working gas (Ar, Kr, Xe) and pressure. Morphology, microstructure, hardness, elastic modulus, and residual stress have been studied through high resolution methodologies. Microstructural analyses consisted of Scanning Electron Microscopy (SEM), X-ray diffraction (XRD) and focused ion beam (FIB) cross section analysis. Moreover, nano-mechanical properties of the films (hardness and modulus) were analyzed by nano-indentation testing while adhesion was evaluated by scratch tests. A recently proposed approach was used to investigate the average residual stress of the produced coatings. It involves incremental FIB milling of annular trenches at material surface, combined with high resolution SEM imaging [1].SEM-FIB and XRD results showed a significant modification of films' microstructure due to selected deposition parameters: it goes from dense-columnar (high crystallite size) at low working pressure and/or high gas mass to nano-porous (small grains) at high pressure and/or low gas mass. This means that the momentum flux carried to the substrate considerably change. In addition residual stress field and mechanical property results are consistent with the coatings' microstructure variations and can be successfully used to confirm them. Finally, it has been found that microstructure and/or mechanical properties of the coatings help to foresee the film/substrate system adhesion. This is fundamental to predict its functional behavior.Therefore, an effective route to tailor the structure and properties of molybdenum coatings was investigated. Modifying synthesis conditions, Mo films can present dense microstructures and good mechanical properties (high Young's modulus and load bearing capacity) demonstrating their potential for applications in harsh environments like thermonuclear fusion plants. Otherwise changing sputtering parameters, they can show a nano-porous structure, suggesting novel applications as for example in the lubrication and catalysis fields. © 2015 Elsevier B.V

Removing of Mixed Coatings by Plasma Discharges

Next generation tokamaks offer the possibility of highly efficient energy generation from the fusion reaction of hydrogen isotopes. In tokamak operation, the core plasma interaction with the wall materials could produce tiles erosion. Redeposition of the eroded materials (C–W–Be) leads to an increase in the allowable tritium load if the coatings are not periodically removed. Amongst removal methods, plasma based techniques employing Ar, H2 gas have been investigated. Plasma cleaning has been carried out on hydrogenated carbon and carbon–tungsten coatings. It has been shown hat at a RF power density of 1.3 W/cm2 (pressure of 1 Pa), the plasma cleaning was effective in removing the coatings. Details of further work in this research activity will be presented