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The deposition of zinc oxide (ZnO) as a window layer in CuInGa(S,Se)2 (CIGS) thin film solar cells was studied in a low power plasma reactor. This deposition technique was used to obtain intrinsic ZnO thin layers from zinc nitrate Zn(NO 3 ) 2 precursors dissolved in water. The liquid solution was injected under a spray form into oxidant plasma at low power (135 W) to be transformed into a ZnO coating deposited onto a substrate. The deposited ZnO films were analyzed to determine the electrical, optical and structural properties (SEM, XRD, FTIR, UV–vis, 4-point probes method). Analysis showed that the thin films were adherent, transparent, homogenous and crystallized under a Wurtzite form. This was in accordance with the required properties for a window layer in CIGS solar cells. In addition, the growth rate of ZnO was determined from micrographs to be equal to 0.61 nm s − 1 in the plasma reactor. This value was compared with the growth rate of usual ZnO deposition techniques and was found to be the highest. This proved that this plasma reactor working at low power is very promising for the deposition of thin films for industrial CIGS application.

The low power plasma reactor is an original process which allows the deposition of ZnO controlled thickness films from an aqueous precursor solution in a cold plasma only in order to reach high growth rates. The quality of the deposited material (purity, crystallinity, size of the grains…) depends primarily on the interactions in the reactor between the droplets and the plasma. In this study, the parameters of the deposition (composition of the gases, pressure, power, temperature…) were studied and controlled. The doping characteristics are mainly influenced by the concentration of the precursors in the solution and by the method of injection. The final optimizations allowed high growth rates ranging from 0.6 to 1 nm/s. X-ray Diffraction results show a good crystallinity of the deposited layer (wurtzite structure). According to the transmittance measurements, the films present a good transparency and a calculated optical gap value ranging between 3.2 and 3.3 eV. This deposition technique using plasma is fast, flexible, low power consuming and easily adaptable. Cu(In,Ga)Se 2 solar cells with a ZnO window layer have successfully been achieved by using the low power plasma reactor and their performances show an efficiency of 11%.

This article belongs to the Special Issue Metabolomics and Its Application in Human Diseases; International audience; There is a rising incidence of non-alcoholic fatty liver disease (NAFLD) as well as of the frequency of Hepato-Cellular Carcinoma (HCC) associated with NAFLD. To seek for putative metabolic pathways specific of the NAFLD etiology, we performed comparative metabolomics between HCC associated with NAFLD and HCC associated with cirrhosis. The study included 28 pairs of HCC tissue versus distant Non-Tumoral Tissue (NTT) collected from patients undergoing hepatectomy. HCC was associated with cirrhosis (n = 9), normal liver (n = 6) and NAFLD (n = 13). Metabolomics was performed using 1H-NMR Spectroscopy on tissue extracts and combined to multivariate statistical analysis. In HCC compared to NTT, statistical models showed high levels of lactate and phosphocholine, and low level of glucose. Shared and Unique Structures (SUS) plots were performed to remove the impact of underlying disease on the metabolic profile of HCC. HCC-cirrhosis was characterized by high levels of β-hydroxybutyrate, tyrosine, phenylalanine and histidine whereas HCC-NAFLD was characterized by high levels of glutamine/glutamate. In addition, the overexpression glutamine/glutamate on HCC-NAFLD was confirmed by both Glutamine Synthetase (GS) immuno-staining and NMR-spectroscopy glutamine quantification. This study provides evidence of metabolic specificities of HCC associated with non-cirrhotic NAFLD versus HCC associated with cirrhosis. These alterations could suggest activation of glutamine synthetase pathway in HCC-NAFLD and mitochondrial dysfunction in HCC-cirrhosis, that may be part of specific carcinogenic processes.

International audience; Background: Localized radiotherapy is long known to cause damages to not only targeted but also non-targeted cells, the so-called bystander (BS) effect. Recently, BS effect was demonstrated in response to chemotherapy. To get further insight into the mechanism of chemotherapy-induced BS effect in vivo, we investigated the response of normal tissues and untreated BS melanomas, at distance from localized chemotherapy-treated melanomas. Methods: 816 melanoma cells were inoculated sc in one flank, in mice. Chemotherapy was administered intratumorally. After 3 weeks, untreated melanomas were implanted into the other flank. Tumors were analyzed morphologically, and using metabolomics and transcriptomics. Results: Locally-treated melanomas showed growth inhibition and pleiotropic metabolic and transcriptional alterations. Tumors recovered slow proliferation while exhibiting prominent oxidative stress response (decreased glutathione level, and increased expression of genes including Mt1, Gpx3, Sod3, and Hmox1). Plasma contained increased levels of oxidative stress products. However, liver and soleus muscle displayed unaltered morphological characteristics. In contrast, untreated BS melanomas induced from naive B16 cells showed reduced growth, marked oxidative stress response (decreased glutathione level, and increased expression of genes including Sod2, Gpx1 and Gsr), and ras oncogene expression alterations. Furthermore, metabolomics and transcriptomics enabled to estimate the proportion of cells undergoing the BS effect within treated tumors. Conclusion: Treatment of tumors with chemotherapy induces BS effects, underpinned by oxidative stress, in abnormal proliferating tissues in vivo, not in normal tissue, that significantly contribute to overall tumor response. General significance BS effect significantly contributes to response to chemotherapy, and may be exploited to improve overall response to cancer treatment.

The application of Laser Induced Breakdown Spectroscopy (LIBS) for the analysis of both solid and molten silicon has been developed. This technique provides fast and reliable chemical characterization of silicon. This work will present the investigation of experimental parameters such as buffering gas nature and pressure in order to find the most suitable conditions to quantify boron in solid silicon. These results show that the signal to background ratio (SBR) is improved by both the use of helium and argon instead of air and by reducing the pressure to 500 mbar. Using calibrated samples, calibration curves were prepared for boron and limits of detection of the order of 0.2 ppm were obtained working at a distance of 50 cm from the sample. Additionally, the capabilities of LIBS to analyze molten silicon (1410 °C) was demonstrated, opening the way for LIBS to be used as a process analytical technique.

Plasma-enhanced chemical vapour deposition (PECVD) was used to prepare thin films of cobalt oxide. Cobalt oxide-based (CoO and Co3O4) catalysts were chosen due to their efficiency in mineralisation of organic pollutants achieved by catalytic ozonation. In this work, two types of PECVD processes were used for the production of cobalt oxide thin films. In the first one, a solution of nitrate salt of cobalt was sprayed into a RF low pressure plasma discharge (40 MHz, 600 Pa, 200 W) to obtain CoxOy layers. In the second MOPECVD (metal organic plasma-enhanced chemical vapour deposition) process, cobalt oxide thin films were deposited using a capacitive coupled external electrodes RF plasma reactor (13.56 MHz, 100 Pa, 200 W) with cobalt carbonyl Co2(CO)8 dissolved in hexene as precursor sprayed in a gas carrier (argon and oxygen). In the case of coatings produced from a solution of cobalt nitrate salt, a layer of 1 μm of Co3O4 in crystalline form was obtained after annealing. Considering the thin films obtained from cobalt carbonyl precursor, analyses confirmed the presence of cobalt oxide in a polymeric layer on the surface of the substrate. XRD investigation showed the presence of a crystalline phase of Co3O4 (crystallite size of about 40 nm).

The principal subject matter of this work is the application of laser-induced breakdown spectroscopy for the multi-elemental analytical characterization of different qualities of solid silicon. The physical process upon which the technique is based is the temporally resolved observation of emission spectra emitted by a micro-plasma generated by a laser focused on the surface of a given sample. The optimal environmental parameters such as the composition of the buffering gas for the identification and measurement of several metallic, non-metallic, and dopant impurities were determined. Particular attention was given to boron. A detection limit of 2.10−4 mg/g of boron was found using a calibration curve, which was made in the range of 1 to 100 ppmw. Silicon samples from different production techniques (4C and directional solidification), which permit the segregation of different impurities along the length of the silicon ingot were analyzed using laser-induced breakdown spectroscopy. Copyright © 2011 John Wiley & Sons, Ltd.

A low pressure plasma process working at 600–800 Pa was used to deposit from aqueous solution ZrO 2 –4 mol% Y 2 O 3 (Yttria partially stabilized Zirconia–YpSZ) layers and stacks of Ta 2 O 5 /YpSZ layers for use as thermal barrier coatings (TBC). The observation of the cross section revealed a high porosity. The thermal diffusivity of the layers (1 × 10 −7 m 2 s −1 ) was measured by a laser flash technique and compared with values obtained on air plasma sprayed material (3 × 10 −7 m 2 s −1 ). The plasma reactor were also used to deposit ZrB 2 –ZrO 2 –SiC layers used as Ultra High Temperature Composite (UHTC) from aqueous solutions of zirconyl and Boron nitrates containing suspensions of SiC. Layers up to 100 μm thick were obtained on SiC substrates. XRD was used to study the crystallinity of the layer. The presence of ZrB 2 and SiC phases was confirmed after the deposition. XRD analysis showed that heat treatment at 1073 K under oxidizing conditions led to the loss of ZrB 2 and the appearance of ZrO 2 phases. To understand the behaviour of the layers to interaction with atomic oxygen (combustion for TBC and spacecraft re-entry phase for UHTC), we have measured the atomic oxygen recombination coefficient to determine the number of adsorption sites on the surface of the coatings. This was accomplished by using a low pressure plasma reactor coupled with optical spectroscopic measurements as a diagnostic technique.

Laser-induced breakdown spectroscopy (LIBS) has been employed for the fast and reliable chemical characterization of silicon used for the photovoltaic industry. Silicon for photovoltaic panels is subject to certain constraints on its purity, and notably must contain low concentration of boron. The use of LIBS could be advantageous because it allows rapid and simultaneous multi-elemental chemical analysis of silicon without any sample preparation. LIBS was applied to boron analysis and a detection limit of 0.23 ppmw was found for optimized gas and pressure conditions.

International audience; Background: BRCA1, the main breast and ovarian cancer susceptibility gene, has a key role in maintenance of genome stability, cell cycle and transcription regulation. Interestingly, some of the numerous proteins which interact with BRCA1 protein undergo conjugation with small ubiquitin-like modifiers (SUMO). This post-translational modification is related to transcription, DNA repair, nuclear transport, signal transduction, and to cell cycle stress response. Methods and results: Protein sequence analysis suggests that sumoylation target sites belong to the RING finger and BRCT domains (BRCA1 C-terminus), two crucial regions for BRCA1 function. Moreover putative SUMO interacting motifs are present in the sequence of many proteins of BRCA1 network. Using immunoprecipitations and western blotting, we show the conjugation of endogenous nuclear BRCA1 protein with SUMO-2/3. BRCA1 conjugation with SUMO-2/3 is linked to the cell cycle in a cell line dependent manner since no cell cycle dependence of sumoylation is observed in MCF7 breast cancer cells. In contrast, BRCA1 conjugation with SUMO-2/3 is linked to the oxidative stress independently to the cell line, in DU145, MCF7 and 293 T cells. Conclusion and general significance: Our data reveal a new BRCA1 regulation pathway implying sumoylation in response to cell cycle progression and oxidative stress, providing a possible mechanism for the involvement of BRCA1 gene in tumorigenesis. (C) 2010 Elsevier B.V. All rights reserved.

The quantification of boron and other impurities in photovoltaic grade silicon was investigated using the LIBS technique with attention to the laser wavelength employed, temporal parameters, and the nature of the ambient gas. The laser wavelength was found to have a moderate effect on the performance of the process, while the type of purge gas and temporal parameters had a strong effect on the signal-to-background ratio (SBR) of the boron spectral emission, which was used to determine the boron concentration in silicon. The three parameters are not independent, meaning that for each different purge gas, different optimal temporal parameters are observed. Electron density was also calculated from Stark broadening of the 390.5 nm silicon emission line in order to better understand the different performances observed when using different gases and gating parameters. Calibration curves were made for boron measurement in silicon using certified standards with different purge gases while using the temporal parameters which had been optimized for that gas. By comparing the calibration curves, it was determined that argon is superior to helium or air for use as the analysis chamber purge gas with an UV laser.

Methionine (Met) deprivation stress (MDS) is proposed in association with chemotherapy in the treatment of some cancers. A synergistic effect of this combination is generally acknowledged. However, little is known on the mechanism of the response to this therapeutic strategy. A model of B16 melanoma tumor in vivo was treated by MDS alone and in combination with chloroethylnitrosourea (CENU). It was applied recent developments in proton-NMR spectroscopy-based metabolomics for providing information on the metabolic response of tumors to MDS and combination with chemotherapy. MDS inhibited tumor growth during the deprivation period and growth resumption thereafter. The combination of MDS with CENU induced an effective time-dependent synergy on growth inhibition. Metabolite profiling during MDS showed a decreased Met content (P < 0.01) despite the preservation of the protein content, disorders in sulfur-containing amino acids, glutamine/proline, and phospholipid metabolism [increase of glycerophosphorylcholine (P < 0.01), decrease in phosphocholine (P < 0.05)]. The metabolic profile of MDS combined with CENU and ANOVA analysis revealed the implication of Met and phospholipid metabolism in the observed synergy, which may be interpreted as a Met-sparing metabolic reprogramming of tumors. It follows that combination therapy of MDS with CENU seems to intensify adaptive processes, which may set limitations to this therapeutic strategy.

Cancer cells mainly rely on glycolysis for energetic needs, and mitochondrial ATP production is almost inactive. However, cancer cells require the integrity of mitochondrial functions for their survival, such as the maintenance of the internal membrane potential gradient (DeltaPsim). It thus may be predicted that DeltaPsim regeneration should depend on cellular capability to produce sufficient ATP by upregulating glycolysis or recruiting oxidative phosphorylation (OXPHOS). To investigate this hypothesis, we compared the response to an anticancer agent chloroethylnitrosourea (CENU) of two transformed cell lines: HepG2 (hepatocarcinoma) with a partially differentiated phenotype and 143B (osteosarcoma) with an undifferentiated one. These cells types differ by their mitochondrial OXPHOS background; the most severely impaired being that of 143B cells. Treatment effects were tested on cell proliferation, O(2) consumption/ATP production coupling, DeltaPsim maintenance, and global metabolite profiling by NMR spectroscopy. Our results showed an OXPHOS uncoupling and a lowered DeltaPsim, leading to an increased energy request to regenerate DeltaPsim in both models. However, energy request could not be met by undifferentiated cells 143B, which ATP content decreased after 48 h leading to cell death, while partially differentiated cells (HepG2) could activate their oxidative metabolism and escape chemotherapy. We propose that mitochondrial OXPHOS background confers a survival advantage to more differentiated cells in response to chemotherapy. This suggests that the mitochondrial bioenergetic background of tumors should be considered for anticancer treatment personalization.

A low pressure plasma process has been developed which enables deposition of oxide layers from micro droplets introduced into a reactor. With this process, up to 50 μm thick porous yttria-stabilized zirconia (YSZ) coatings have been deposited. Zirconyl and yttrium nitrates (ZrO(NO 3 ) 2 and Y(NO 3 ) 3 ) dissolved in water were used as precursors. These precursors are introduced as micrometric droplets into a plasma discharge. After interacting with the plasma, the droplets are deposited onto the substrate to form the YSZ coating. The velocity and diameter of the solution droplets injected into the reactor were studied with an on-line Particle Dynamics Analyser to propose a mechanism for the formation of the coating. The structure and composition of the coatings have been characterized by Scanning Electron Microscopy (+ EDX) and X-ray Diffraction. The results obtained show that the deposited 7YSZ coatings exhibit a morphology compatible with TBC applications.

The aim of this work is the purification and the hydrogenation of metallurgical grade silicon for photovoltaic applications using a thermal plasma process. In addition to the plasma treatment, a DC bias of the liquid silicon was used to increase the kinetics of impurity extraction and hydrogenation reaction. On-line measurement by OES (Optical Emission Spectroscopy), ex-situ analysis by LIBS (Laser Induced Breakdown Spectroscopy) and ICP techniques demonstrated that elimination of metallic impurities and boron depends on the applied bias, and/or on the plasma gas composition. The DC bias was found to significantly increase the hydrogenation rate of liquid silicon, when it is attributed to electrochemical and/or chemical reactions in the electrical plasma sheath.

The aim of this work is the purification of metallurgical grade silicon for photovoltaic applications using a thermal plasma process. In this study, the plasma treatment was combined with a DC bias of the liquid silicon to increase the kinetics of the impurities extraction. On-line measurement by optical emission spectroscopy (OES), ex-situ analysis by laser induced breakdown spectroscopy (LIBS) and ICP techniques allowed to demonstrate that elimination of cationic impurities (Fe, Al, Ca, etc.) increased when the positive bias increased. The ICP results show that a high positive bias leads to a purification factor of about 10 for most of the impurities.

A low pressure plasma process was used in the laboratory to synthesize very pure Sr-doped LaMnO 3 porous layers, which could be used as a SOFC cathode. Recent experimental work allowed to adapt the process to synthesize both the YSZ dense electrolyte and the NiO–YSZ porous anode in one step. The raw material was a mixture of Y and ZrO nitrates dissolved in water. Nitrates were introduced in the argon/oxygen plasma discharge in order to obtain on a quartz substrate a very pure YSZ layer at low temperature ( T ≤ 360 K). After depositing YSZ as a layer, Ni nitrates were progressively added to the mixture of Y and ZrO nitrates in order to obtain a NiO–YSZ layer presenting concentration gradients. SEM-EDX analyses were performed on the fractured cross section of the YSZ/NiO–YSZ/NiO stack. Micrographs showed that the YSZ layer is dense, contrary to the porous NiO–YSZ and NiO ones. EDX analyses confirmed the purity and the composition of the YSZ layer. The presence of concentration gradients of Ni and YSZ along the cross section was demonstrated: contrary to the YSZ concentration, the Ni one increases from the YSZ layer up to the surface. No Y and Zr elements were detected at the surface of the YSZ/NiO–YSZ/NiO stack.

The ceramic layer of a thermal barrier coating is usually deposited by plasma spraying or by EBPVD (Electron Beam Physical Vapour Deposition). To explore the potential of new oxide compositions in view of thermal barrier coating applications, these deposition techniques may be difficult to apply on account of the unavailability of suitable oxide powders for plasma spraying, for example, or the difficulty to determine the appropriate evaporation conditions for complex oxides in EBPVD. However a flexible technique has been developed, which enables to deposit a wide range of oxide compounds with minimal investment. This technique is based on the injection of micrometric droplets of solution containing the elements to deposit, into a plasma reactor equipped with a convergent nozzle. The first results concerning the deposition of thick oxide layers of Yttria-Stabilized Zirconia (YSZ) and that of a high temperature complex perovskite Ba 3 MgTa 2 O 9 are given, with micro structural and chemical characterization (SEM, XRD, FTIR). YSZ grew into a layer 1 μm mn − 1 thick and exhibited vertical cracks from the surface to the substrate. The stoichiometry of the layer was in accordance with the composition of the precursors solution. The Ba 3 MgTa 2 O 9 coating deposited was homogenous and presented cracks at the surface. The observation of the cross section revealed a layer up to 100 μm thick. Vertical cracks and lamellar porous microstructures, which could be favourable to thermal barrier applications, were visible along the cross section.

Resume Le but de ce travail etait d’evaluer la fixation du 18FDG en TEP dans les lymphomes de Hodgkin en fonction de differents parametres histopathologiques ainsi que l’impact de l’examen sur la stadification et le suivi. Un total de 37 patients a beneficie d’une evaluation TEP-TDM pretherapeutique. La standardized uptake value (SUV) a ete calculee a posteriori. Celle-ci est superieure dans les lymphomes de Hodgkin a cellularite mixte, comparativement aux scleronodulaires. Par ailleurs, l’examen a entraine un changement de stade dans 35 % des cas comparativement a la TDM injectee. La specificite de la TEP-TDM en fin de traitement a ete de 96 % et son exactitude de 93 %, toutes deux significativement superieures a celles retrouvees en TDM.

Hydrogenation by plasma is a low cost and efficient method to improve the photovoltaic properties of multicrystalline silicon. The role of plasma parameters on the efficiency of hydrogenation was studied using secondary ion mass spectrometry (SIMS), hydrogen effusion, electrochemical impedance spectroscopy and electron beam induced current (EBIC). The experimental results showed a deuterium concentration of 1020 atoms cm−3 could be reached in the sample after a 15-min treatment. Optimal treatment time depends on temperature and leads to maximum electrical conductivity and minority carrier diffusion length. The results confirm the reduction of defects densities and potential barriers associated with grain boundaries.

The Low Power Plasma Reactor is an original process which allows a rapid deposition of ZnO thin films with calibrated thickness. The deposition is performed by the spraying of an aqueous precursor solution in cold plasma. The final optimizations allow high average growth rates reaching 0.6 nm/s. Characterization of films (XRD, FTIR, Transmittance, resistivity measures) reports the expected crystallinity, composition, the needed transparency and a calculated optical gap value ranging between 3.2–3.3 e V. The resistivity of layers was studied to be decreased in order to improve the electric properties of thin films. The performances of Cu(In,Ga)Se2 solar cells with a plasma sprayed intrinsic ZnO (i-ZnO) layer showed efficiencies around 15% (equivalent value with classic sputtered i-ZnO).

The aim of this work was to synthesise and deposit a perovskite (La1-xSrxMnO3 or La1-xSrxCoO3) cathode on an SOFC electrolyte (8% Yttria Stabilised Zirconia – YSZ). The recombination of atomic oxygen on Sr doped LaMnO3 was performed in order to study the properties of perovskite for the adsorption of oxygen. The electrical resistance of the layers was measured as a function of the chemical composition. Impedance measurements on different samples were performed in order to analyse the electrochemical response of the cathode – electrolyte stack as a function of temperature and nature of the atmosphere. Moreover, the Faradaic impedance representing the electrochemical processes at the cathode – electrolyte interface was calculated from the global impedance in various conditions.