Synthesis of T-Nb2O5 thin-films deposited by Atomic Layer Deposition for miniaturized electrochemical energy storage devices

Atomic Layer Deposition has been used to grow 30 to 90 nm-thick amorphous Nb2O5 films onto Pt current collectors deposited on Si wafer. While T-Nb2O5 polymorph is obtained by further annealing at 750 °C, the film thickness and the resulting electrode areal capacity are successfully controlled by tuning the number of ALD cycles. The electrochemical analysis reveals a lithium ion intercalation redox mechanism in the T-Nb2O5 electrode. An electrode areal capacity of 8 μAh cm-² could be achieved at 1 C, with only 40% capacity loss at 30 C(2 minutes discharging time). This paper aims at demonstrating the use of Atomic Layer Deposition method in the fabrication of Nb205-based on-chip micro-devices for Internet of Things (IoT) applications

Individual patient data meta-analysis of neoadjuvant chemotherapy followed by surgery versus upfront surgery for carcinoma of the oesophagus or the gastro- oesophageal junction

Introduction Which neoadjuvant treatment for locally advanced thoracic oesophagus (TE) or gastro-oesophageal junction carcinoma is best remains an open question. Randomised controlled trials variously accrued patients with adenocarcinoma and squamous cell carcinoma, making strong conclusions hard to obtain. The primary objective of this individual participant data meta-analysis was to investigate the effect of neoadjuvant chemotherapy on overall survival (OS). Patients and methods Eligible trials should have closed to accrual before 2016 and compared neoadjuvant chemotherapy and surgery (CS) to surgery alone. All relevant published and unpublished trials were identified via searches of electronic databases, conference proceedings and clinical trial registers. The main end-point was OS. Investigators were contacted to obtain the individual patient data, which was recorded, harmonised and checked. A random-effects Cox model, stratified by trial, was used for meta-analysis and subgroup analyses were preplanned. Results 16 trials were identified as eligible. Individual patient data were obtained from 12 trial and 2478 patients. CS was associated with an improved OS versus surgery, hazard ratio (HR) = 0.83 [0.72–0.96], p < 0.0001, translating to an absolute benefit of 5.7% at 5-years from 16.8% to 22.5%. Treatment effects did not vary substantially between adenocarcinoma (HR = 0.73 [0.62–0.87]) and squamous cell carcinoma (HR = 0.91 [0.76–1.08], interaction p = 0.26). A somewhat more pronounced effect was observed in gastro-oesophageal junction (HR = 0.68 [0.50–0.93]) versus TE (HR = 0.87 [0.75–1.00], interaction p = 0.07). CS was also associated with a greater disease-free survival (HR = 0.74 [0.64–0.85], p < 0.001). Conclusions Neoadjuvant chemotherapy conferred a better OS than surgery alone and should be considered in all anatomical location and histological subtypes

Individual Participant Data Network Meta-Analysis of Neoadjuvant Chemotherapy or Chemoradiotherapy in Esophageal or Gastroesophageal Junction Carcinoma

PURPOSE: The optimal neoadjuvant treatment for resectable carcinoma of the thoracic esophagus (TE) or gastroesophageal junction (GEJ) remains a matter of debate. We performed an individual participant data (IPD) network meta-analysis (NMA) of randomized controlled trials (RCTs) to study the effect of chemotherapy or chemoradiotherapy, with a focus on tumor location and histology subgroups. PATIENTS AND METHODS: All, published or unpublished, RCTs closed to accrual before December 31, 2015 and having compared at least two of the following strategies were eligible: upfront surgery (S), chemotherapy followed by surgery (CS), and chemoradiotherapy followed by surgery (CRS). All analyses were conducted on IPD obtained from investigators. The primary end point was overall survival (OS). The IPD-NMA was analyzed by a one-step mixed-effect Cox model adjusted for age, sex, tumor location, and histology. The NMA was registered in PROSPERO (CRD42018107158). RESULTS: IPD were obtained for 26 of 35 RCTs (4,985 of 5,807 patients) corresponding to 12 comparisons for CS-S, 12 for CRS-S, and four for CRS-CS. CS and CRS led to increased OS when compared with S with hazard ratio (HR) = 0.86 (0.75 to 0.99), P = .03 and HR = 0.77 (0.68 to 0.87), P &lt; .001 respectively. The NMA comparison of CRS versus CS for OS gave a HR of 0.90 (0.74 to 1.09), P = .27 (consistency P = .26, heterogeneity P = .0038). For CS versus S, a larger effect on OS was observed for GEJ versus TE tumors (P = .036). For the CRS versus S and CRS versus CS, a larger effect on OS was observed for women (P = .003, .012, respectively). CONCLUSION:Neoadjuvant chemotherapy and chemoradiotherapy were consistently better than S alone across histology, but with some variation in the magnitude of treatment effect by sex for CRS and tumor location for CS. A strong OS difference between CS and CRS was not identified.</p

New uranium peroxides and peroxo-oxalates as oxides precursors : synthesis and characterization

Les recherches actuelles sur les cycles nucléaires du futur sont axées notamment sur le traitement-recyclage du combustible nucléaire dit “usé“ avec la préparation de solides mixtes à base d’actinides, matières premières pour la fabrication de nouveaux combustibles. A l’issue des cycles de séparation-purification lors du traitement du combustible, l’étape de conversion des actinides en solution en oxyde mixte est une des étapes clés de cette démarche. Actuellement le plutonium est précipité sous forme oxalate et de nombreuses études de la précipitation et décomposition d’oxalates mixtes ont été réalisées. Quant à l’uranium, il est précipité sous forme de peroxyde d’uranyle, l’utilisation de peroxydes mixtes voire peroxo-oxalates comme précurseurs d’oxydes est donc une voie à explorer. L’objectif de cette étude est d’instruire la potentialité d’une telle voie peroxyde. Dans une première étape, l’examen du système NH4+/UO22+/O22-/C2O42-, a mis en évidence la formation de plusieurs peroxydes et peroxo-oxalates sous forme de polyanions isolés ou de nanoclusters conduisant, par décomposition thermique, à des oxydes d’uranium. Dans une seconde étape, partant de nanoclusters d’uranyle et d’ammonium des peroxydes d’uranium et de lanthanides ou de thorium ont été préparés et caractérisés par diffraction X sur monocristal et sur poudre, par analyse ICP-AES, par microscopie électronique et par spectroscopies UV-visible et IR. Leur décomposition en oxydes mixtes a été étudiée sous différentes atmosphères.One of the current researches on future nuclear cycle is spent nuclear fuel treatment and recycling, where actinides mixed solids are prepared as raw materials for nuclear fuel refabrication. After separating-purification cycle during spent nuclear fuel treatment, the conversion step of actinides from solution to mixed oxide is one of the key stages. Currently, plutonium is recovered by oxalic precipitation and numerous studies on its precipitation and oxalate decomposition have been done. Meanwhile, in the case of uranium, a uranyl peroxide is precipitated. Therefore, a route to investigate is the use of peroxides or peroxo-oxalates as oxides precursors. The main goal of this study is to study the feasibility of such method. In a first step, examination of NH4+/UO22+O22-/C2O42- system has highlighted the evidence of many peroxides or peroxo-oxalates formed as polyanions or nanoclusters. These entities lead to uranium oxides after calcination. In a second step, using uranyl nanoclusters, mixed uranium - lanthanide or uranium - thorium compounds were prepared and characterised by single crystal and powder X-ray diffraction, ICP-AES analysis, electron microscopy, UV-Vis and IR spectroscopy. Their decomposition in mixed oxides has been studied under different atmospheres

Nouveaux peroxydes et peroxo-oxalates à base d'uranium, précurseurs d'oxydes (synthèse et caractérisation)

Les recherches actuelles sur les cycles nucléaires du futur sont axées notamment sur le traitement-recyclage du combustible nucléaire dit usé avec la préparation de solides mixtes à base d actinides, matières premières pour la fabrication de nouveaux combustibles. A l issue des cycles de séparation-purification lors du traitement du combustible, l étape de conversion des actinides en solution en oxyde mixte est une des étapes clés de cette démarche. Actuellement le plutonium est précipité sous forme oxalate et de nombreuses études de la précipitation et décomposition d oxalates mixtes ont été réalisées. Quant à l uranium, il est précipité sous forme de peroxyde d uranyle, l utilisation de peroxydes mixtes voire peroxo-oxalates comme précurseurs d oxydes est donc une voie à explorer. L objectif de cette étude est d instruire la potentialité d une telle voie peroxyde. Dans une première étape, l examen du système NH4+/UO22+/O22-/C2O42-, a mis en évidence la formation de plusieurs peroxydes et peroxo-oxalates sous forme de polyanions isolés ou de nanoclusters conduisant, par décomposition thermique, à des oxydes d uranium. Dans une seconde étape, partant de nanoclusters d uranyle et d ammonium des peroxydes d uranium et de lanthanides ou de thorium ont été préparés et caractérisés par diffraction X sur monocristal et sur poudre, par analyse ICP-AES, par microscopie électronique et par spectroscopies UV-visible et IR. Leur décomposition en oxydes mixtes a été étudiée sous différentes atmosphères.One of the current researches on future nuclear cycle is spent nuclear fuel treatment and recycling, where actinides mixed solids are prepared as raw materials for nuclear fuel refabrication. After separating-purification cycle during spent nuclear fuel treatment, the conversion step of actinides from solution to mixed oxide is one of the key stages. Currently, plutonium is recovered by oxalic precipitation and numerous studies on its precipitation and oxalate decomposition have been done. Meanwhile, in the case of uranium, a uranyl peroxide is precipitated. Therefore, a route to investigate is the use of peroxides or peroxo-oxalates as oxides precursors. The main goal of this study is to study the feasibility of such method. In a first step, examination of NH4+/UO22+O22-/C2O42- system has highlighted the evidence of many peroxides or peroxo-oxalates formed as polyanions or nanoclusters. These entities lead to uranium oxides after calcination. In a second step, using uranyl nanoclusters, mixed uranium - lanthanide or uranium - thorium compounds were prepared and characterised by single crystal and powder X-ray diffraction, ICP-AES analysis, electron microscopy, UV-Vis and IR spectroscopy. Their decomposition in mixed oxides has been studied under different atmospheres.LILLE1-Bib. Electronique (590099901) / SudocSudocFranceF

: Évolution typologique et technique des meules du Néolithique à l’an mille

International audienc

Micro-diffraction study of sputtered LiMn1.5Ni0.5O4 thin films for Li-ion micro-batteries

International audienc

Formal base-free homolytic aromatic substitutions via photoredox catalysis

We developed a simple and convenient method to assemble biaryls exploiting a photoredox catalyst and visible light. Diazonium salts generate aryl radicals that could then add on unactivated (hetero)arenes and the sequence eventually delivers products via formal homolytic aromatic substitutions. The direct C–H arylation of these usually unreactive substrates is achieved at room temperature using low catalyst loadings and shows broad functional group toleranc

The Paris CM chondrite: Secondary minerals and asteroidal processing

International audienceAbstract-We report a petrographic and mineralogical survey of Paris, a new CM chondrite considered to be the least-altered CM identified so far (Hewins et al. 2014). Compared to other CMs, Paris exhibits (1) a higher concentration of Fe-Ni metal beads, with nickel contents in the range 4.1-8.1 wt%; (2) the systematic presence of thin lamellae and tiny blebs of pentlandite in pyrrhotite grains; and (3) ubiquitous tochilinite/cronstedtite associations with higher FeO/SiO2 and S/SiO2 ratios. In addition, Paris shows the highest concentration of trapped 36Ar reported so far for a CM chondrite (Hewins et al. 2014). In combination with the findings of previous studies, our data confirm the reliability of (1) the alteration sequence based on the chemical composition of tochilinite/cronstedtite associations to quantify the fluid alteration processes and (2) the use of Cr content variability in type II ferroan chondrule olivine as a proxy of thermal metamorphism. In contrast, the scales based on (1) the Fe3+ content of serpentine in the matrix to estimate the degree of aqueous alteration and (2) the chemical composition of Fe-Ni metal beads for quantifying the intensity of the thermal metamorphism are not supported by the characteristics of Paris. It also appears that the amount of trapped 36Ar is a sensitive indicator of the secondary alteration modifications experienced by chondrites, for both aqueous alteration and thermal metamorphism. Considering Paris, our data suggest that this chondrite should be classified as type 2.7 as it suffered limited but significant fluid alteration and only mild thermal metamorphism. These results point out that two separated scales should be used to quantify the degree of the respective role of aqueous alteration and thermal metamorphism in establishing the characteristics of CM chondrite