Ballistic and molecular dynamics simulations of aluminum deposition in micro-trenches

Two different feature scale modeling frameworks are utilized for the study of aluminum (Al) deposition profiles inside micro-trenches. The first framework, which is applied in metal-organic chemical vapor deposition (MOCVD) of Al, couples a ballistic model for the local flux calculation, a surface chemistry model, and a profile evolution algorithm. The calculated conformity of the deposited film is compared with experimental results corresponding to Al MOCVD from dimethylethylamine alane (DMEAA). The outcome of the comparison is that the effective sticking coefficient of DMEAA is in the range of 0.1 - 1. There is also a strong indication that surface reaction kinetics follows Langmuir - Hinshelwood or Eley - Rideal mechanism. The second framework, which is applied in physical vapor deposition of Al, implements 2D molecular dynamics (MD) simulations. The simulations are performed in a "miniaturized" domain of some hundreds of Angstroms and are used to explore micro-trench filling during magnetron sputtering deposition of Al on a rotated substrate. Most of the experimental results are qualitatively reproduced by the MD simulations; the rotation, aspect ratio, and kinetic energy effects are correctly described despite the completely different length scales of simulation and experiment. The sticking probability of Al is calculated 0.6 for the conditions of the experiments

Optimization of DC reactive magnetron sputtering deposition process for efficient YSZ electrolyte thin film SOFC

International audienceYttria-stabilized zirconia (YSZ, ZrO2:Y2O3) thin films were deposited by reactive DC magnetron sputtering with a high deposition rate from a metallic target of Zr/Y in an argon/oxygen atmosphere. Plasma parameters and composition analysis of the gas phase reveal that the sputtering process in the "compound" mode is reached for a 2.5 sccm oxygen flow rate. Deposition onto silicon in "metal" mode at a flow rate close to the transition, allows obtaining at very high deposition rates (> 10 µm.h-1) a compact columnar stoichiometric crystallized YSZ film. When deposited on NiO YSZ commercial anode, the obtained coatings show the same properties. In spite of the complexity of the substrate (roughness and porosity), a compact and conformed layer was formed. Annealing treatments in air or hydrogen do not significantly alter the structure of the layers. Electrochemical test at 850°C with a screen-printed LSM (LaSrMnO3) cathode exhibits a satisfying gastightness (OCV=900 mV) and a maximum power density of 350 mW.cm-2

Energy transferred to the substrate surface during reactive magnetron sputtering of aluminum in Ar/O2 atmosphere

International audienceA study of the reactive sputtering of aluminum was carried out by coupling energy flux measurements at the substrate location with conventional diagnostics of the gas phase and analyses of the deposited films. The main purpose was to get some insight into the elementary mechanisms involved at the substrate surface during the film growth in the well known metal and oxide regimes and at the transitions from one to another. Measurements were carried out in front of a 10 cmAl target at a power of 400W (i.e. 5 W/cm2) and a total pressure of 0.6 Pa. The flow rate ratio (O2/O2+Ar) was varied in the range 0 to 50 %. Different kinetics and values of energy transfer, denoting different involved mechanisms, were evidenced at metal-oxide (increasing flow rate) and oxide-metal (decreasing flow rate) transitions. The metal-oxide transition was found to be a progressive process, in agreement with optical emission spectroscopy and deposit analysis, characterized by an increase of the energy flux that could be due to the oxidation of the growing metal film. On the contrary, oxide-metal transition is abrupt, and a high energy released at the beginning that could not be attributed to a chemical reaction. The possible effect of O-ions at this step was discussed

Influence of the HiPIMS voltage on the time resolved platinum ions energy distributions

International audienceHigh Power Impulse magnetron sputtering (HiPIMS) is a common way to create a high and dense ionized metallic vapor without the use of an alternative ionizing device, like radio frequency loops. HiPIMS has been used to perform the deposition of platinum thin films in order to control their morphology. This feature known to depend on the energy of the Pt species incoming onto the substrate during the deposition has to be carefully studied. Therefore, it's necessary to study the ions energy distribution during the sputtering pulse and to follow its evolution with the HiPIMS regime. Pictures of this evolution are presented

Association of Baseline Inflammation With Effectiveness of Nutritional Support Among Patients With Disease-Related Malnutrition

Importance: Inflammation is a key driver of malnutrition during illness and is often accompanied by metabolic effects, including insulin resistance and reduction of appetite. However, it still remains unclear if inflammation influences the response to nutritional support among patients with disease-related malnutrition. Objective: To examine whether patients' baseline inflammatory status is associated with the effect of nutritional support on 30-day mortality. Design, setting, and participants: This is a secondary analysis of the Effect of Early Nutritional Support on Frailty, Functional Outcomes, and Recovery of Malnourished Medical Inpatients Trial (EFFORT), a randomized clinical trial conducted in 8 Swiss hospitals from April 2014 to February 2018. A total of 1950 participants who had C-reactive protein measurements at the time of admission were included in this secondary analysis. Data analysis was conducted between June and July 2019. Interventions: Hospitalized patients at risk for malnutrition were randomly assigned to receive protocol-guided individualized nutritional support to reach protein and energy goals (intervention group) or standard hospital food (control group). Main outcomes and measures: The primary end point was 30-day mortality. Based on C-reactive protein levels at admission, patients were stratified into groups with low, moderate, or high inflammation (100 mg/L, respectively). Results: A total of 1950 patients (median [interquartile range] age, 75 [65-83] years; 1025 [52.6%] men) were included; 533 (27.3%) had low levels of inflammation, 894 (45.9%) had moderate levels of inflammation, and 523 (26.8%) had high levels of inflammation. Compared with the control group, patients receiving nutritional support showed a significant reduction in 30-day mortality, regardless of C-reactive protein level (adjusted odds ratio, 0.61; 95% CI, 0.43-0.86; P = .005). In the subgroup of patients with high inflammation, there was no beneficial effect of nutritional support (adjusted odds ratio, 1.32; 95% CI, 0.70-2.50; P = .39), providing evidence that inflammation has a significant modifying association (P for interaction = .005). Conclusions and relevance: Based on this secondary analysis of a multicenter randomized trial, a patient's admission inflammatory status was associated with their response to nutritional support. If validated in future clinical trials, nutritional support may need to be individualized based on a patient's initial presentation and markers of inflammation. These results may also help to explain some of the heterogeneity in treatment effects of nutrition seen in previous critical care trials. Trial registration: ClinicalTrials.gov Identifier: NCT02517476

Six-month outcomes after individualized nutritional support during the hospital stay in medical patients at nutritional risk: Secondary analysis of a prospective randomized trial.

BACKGROUND Among medical inpatients at risk of malnutrition, the use of individualized nutritional support during the hospital stay was found to reduce complications and improve mortality at short-term. We evaluated clinical outcomes at 6-months follow-up. METHODS We randomly assigned 2028 patients to receive protocol-guided individualized nutritional support to reach protein and energy goals (intervention group) or hospital food as usual (control group) during the hospital stay. The intervention was discontinued at hospital discharge and further nutritional support was based on the discretion of the treating team. We had complete follow-up information of 1995 patients (98%), which were included in the final analysis. The primary endpoint was all-cause mortality at 6-months. Prespecified secondary end points included non-elective hospital readmissions, functional outcome and quality of life. RESULTS At 6-month, 231 of 994 (23.2%) intervention group patients had died compared to 246 of 999 (24.6%) control group patients, resulting in a hazard ratio for death of 0.90 (95%CI 0.76 to 1.08, p = 0.277). Compared to control patients, intervention group patients had similar rates of hospital readmission (27.3% vs. 27.6%, HR 1.00 (95%CI 0.84 to 1.18), p = 0.974), falls (11.2% vs. 10.9%, HR 0.96 (95%CI 0.72 to 1.27), p = 0.773) and similar quality of life and activities of daily living scores. INTERPRETATION While individualized nutritional support during the hospital stay significantly reduced short-term mortality, there was no legacy effect on longer term outcomes. Future trials should investigate whether continuation of nutritional support after hospital discharge reduces the high malnutrition-associated mortality rates in this vulnerable patient population. TRIAL REGISTRATION ClinicalTrials.gov number, NCT02517476

Arabidopsis CULLIN3 Genes Regulate Primary Root Growth and Patterning by Ethylene-Dependent and -Independent Mechanisms

CULLIN3 (CUL3) together with BTB-domain proteins form a class of Cullin-RING ubiquitin ligases (called CRL3s) that control the rapid and selective degradation of important regulatory proteins in all eukaryotes. Here, we report that in the model plant Arabidopsis thaliana, CUL3 regulates plant growth and development, not only during embryogenesis but also at post-embryonic stages. First, we show that CUL3 modulates the emission of ethylene, a gaseous plant hormone that is an important growth regulator. A CUL3 hypomorphic mutant accumulates ACS5, the rate-limiting enzyme in ethylene biosynthesis and as a consequence exhibits a constitutive ethylene response. Second, we provide evidence that CUL3 regulates primary root growth by a novel ethylene-dependant pathway. In particular, we show that CUL3 knockdown inhibits primary root growth by reducing root meristem size and cell number. This phenotype is suppressed by ethylene-insensitive or resistant mutations. Finally, we identify a function of CUL3 in distal root patterning, by a mechanism that is independent of ethylene. Thus, our work highlights that CUL3 is essential for the normal division and organisation of the root stem cell niche and columella root cap cells

Caractérisation du complexe Culline3-BTB chez Arabidopsis thaliana

La protéolyse ubiquitine-dépendante est un mécanisme conservé chez les eucaryotes permettant la dégradation ciblée de nombreuses protéines. Cette réaction se fait en trois étapes successives qui font intervenir l activité de trois types d enzymes. Une enzyme d activation, ubiquitin-activating ou E1, prend en charge l ubiquitine libre et la transfère sur une enzyme de conjugaison, ubiquitin-conjugating ou E2. L ubiquitine est ensuite liée au substrat par l intermédiaire d une ubiquitin-ligase ou E3. C est l enzyme E3 qui a la fonction la plus importante dans ce processus car c est elle qui détermine la spécificité de reconnaissance de la protéine à dégrader. Il en existe de différents types que l on peut regrouper en sept classes distinctes selon leur mode d action et leur structure. L une des classes est représentée par le complexe CUL3-BTB/POZ (Bric à brac, Tramtrack and Broad complex/Pox virus and Zinc finger). Le génome d Arabidopsis thaliana possède deux gènes codant pour des homologues de la Culline 3, nommés CUL3A et CUL3B. Au cours de mon travail de thèse j ai participé à la caractérisation fonctionnelle de cette enzyme. Ainsi nous avons montré que les deux gènes CUL3A et CUL3B sont exprimés de manière ubiquitaire. De plus, nous avons identifié 76 protéines à domaine BTB dans le génome d Arabidopsis et montré que certaines d entres elles interagissent avec les deux protéines CUL3A et CUL3B dans la levure. Les deux Cullines 3 d Arabidopsis interagissent également avec la protéine Rbx1. Dans le but d identifier la fonction du gène CUL3A nous avons utilisé une approche par génétique inverse. Nous avons ainsi pu montrer que le mutant nul de la cul3a fleurit plus tardivement que la plante contrôle et qu il présente une sensibilité réduite à la lumière rouge lointaine.Nous avons ensuite caractérisé plus en détail, l expression des deux gènes CUL3A et CUL3B dans le tissus et organes reproducteurs et observé qu ils sont exprimés de manière similaires dans la fleur et au cours de l embryogenèse. Nous avons alors analysé les conséquences pour la plante de la perte de fonction de ces deux gènes en créant un double mutant. Les résultats obtenus montrent que la perte de fonction des cullines 3 chez Arabidopsis réduit la transmission gamétophytique et cause la létalité embryonnaire avec un arrêt prédominant au stade cœur du développement de l embryon. Au niveau cytologique ces embryons avortés présentent des aberrations du plan de formation de l embryon et de l endosperme. Finalement, mes travaux en cours mettent en évidence la participation des cullines 3 dans la régulation de la synthèse de l éthylène mais aussi dans le contrôle de la transition entre le stade végétatif et le stade floral.Ubiquitin-dependent degradation by the 26S proteasome has emerged as a central mechanism to control protein turnover in eukaryotes. Ubiquitin transfer requires the activity of E1 (ubiquitin activating), E2 (ubiquitin conjugating) and E3 (ubiquitin ligase) enzymes. Ubiquitin ligases are multiprotein complexes that specifically recognize the substrates and mediate their ubiquitin-dependent degradation. To date several classes of E3s have been reported, most of them based on a protein with cullin domain. Eukaryote genomes encode several cullins: CUL1, CUL2, CUL3, CUL4 and CUL5, which are all believed to form protein complexes with ubiquitin-ligase activity. I focused my work on one of these cullin based E3 ligase, the CUL3-BTB complex.In this report, I describe the molecular and genetic characterizations of the plant Cullin3. We found that CUL3A is ubiquitously expressed in plants and is able to interact with the ring-finger protein RBX1. Yeast two-hybrid experiments indicate that BTB-domain proteins are able to physically interact with both CUL3A and CUL3B, suggesting that Arabidopsis CUL3 forms E3 protein complexes with certain BTB proteins. In order to determine the function of CUL3A, we used a reverse genetic approach. The cul3a null mutants flowers slightly later than the control plants. Homozygous cul3b mutant plants developed normally and were fully fertile. Thus, we investigated the consequences on plant development of combined Arabidopsis cul3a cul3b loss-of-function mutations. The disruption of both the CUL3A and CUL3B genes reduced gametophytic transmission and caused embryo lethality. Arrest of embryogenesis occurred at multiple stages of embryo development, but predominantly at the heart stage. At the cytological level, CUL3 loss-of-function mutations affected both embryo pattern formation and endosperm development. In addtion, recent results show that the Culline 3 is also involved in the regulation of ethylene biosynthesis.STRASBOURG-Sc. et Techniques (674822102) / SudocSudocFranceF