Tailoring the structural and microstructural properties of nanosized tantalum oxide for high temperature electrochemical gas sensors.

Ta2O5 nanopowders to be used as sensing electrodes in high temperature electrochemical gas sensors for hydrocarbons detection were synthesized using a sol-gel method and their structural and microstructural properties were investigated. The as-synthesized powders were heated at different temperatures in the range 250-1000 degrees C and characterized by TG-DTA, XRD, SEM, TEM and FT-IR. This investigation allowed to identify the correct thermal treatments to achieve the microstructural, textural and functional stability of materials working at high temperature, preserving their nano-metric grain size. Planar sensors fabricated by using Ta2O5 powders treated at 750 degrees C showed promising results for the selective detection of propylene at high temperature (700 degrees C). The good stability of the sensing response after gas exposure at high temperature was correlated to the stable microstructure the electrodes. Thus, Ta2O5 powders seems good candidate as sensing electrode for sensors for automotive exhausts monitoring.

Antiangiogenic effects in patients with progressive desmoplastic small round cell tumor: data from the French national registry dedicated to the use of off-labeled targeted therapy in sarcoma (OUTC's).

BACKGROUND: Desmoplastic small round cell tumor (DSRCT) is a very rare mesenchymal tumor that mainly affects teenagers and young adults with a mean age at diagnosis around 20-25 years. Although initial management still needs standardization, many centers will use multimodal treatment including intensive chemotherapy, extensive surgical resection followed by radiotherapy. Despite this, prognosis remains very poor and the median overall survival is 25 months. Recurrent disease is mainly treated by chemotherapy. Recently, due to the unmet medical need for recurrent disease, targeted therapies were explored for DSRCT. METHODS: In this study, we assessed the response rate and progression free survival in nine cases of progressive DSRCT included in the OUTC's registry and treated with antiangiogenics targeted agents (sunitinib, sorafenib and bevacizumab). OUTC's, a French national registry, collects data about the use of off-label targeted therapy in sarcoma. RESULTS: Eight males and one woman were included, with median age at diagnosis of 27.3 years (range from 9 to 48 years). They received a mean 3 lines (2-5) of treatment before antiangiogenic agent initiation. Six patients received sunitinib, two received sorafenib and one bevacizumab. Median progression free survival was 3.1 months (range 2-5.5 months) and best response observed was 5.5 months stable disease. Most patients had manageable low-grade toxicities, mainly fatigue, abdominal pain and skin toxicity. CONCLUSIONS: Despite very limited activity of antiangiogenics in our study, prospective collection of cases of these rare tumors together with molecular data should guide therapeutic decision and enhance outcome.

Mesoporous nanostructured Nb-doped titanium dioxide microsphere catalyst supports for PEM fuel cell electrodes.

Crystalline microspheres of Nb-doped TiO(2) with a high specific surface area were synthesized using a templating method exploiting ionic interactions between nascent inorganic components and an ionomer template. The microspheres exhibit a porosity gradient, with a meso-macroporous kernel, and a mesoporous shell. The material has been investigated as cathode electrocatalyst support for polymer electrolyte membrane (PEM) fuel cells. A uniform dispersion of Pt particles on the Nb-doped TiO(2) support was obtained using a microwave method, and the electrochemical properties assessed by cyclic voltammetry. Nb-TiO(2) supported Pt demonstrated very high stability, as after 1000 voltammetric cycles, 85% of the electroactive Pt area remained compared to 47% in the case of commercial Pt on carbon. For the oxygen reduction reaction (ORR), which takes place at the cathode, the highest stability was again obtained with the Nb-doped titania-based material even though the mass activity calculated at 0.9 V vs RHE was slightly lower. The microspherical structured and mesoporous Nb-doped TiO(2) is an alternative support to carbon for PEM fuel cells.

Single step elaboration of size-tuned Pt loaded titania nanofibres.

Conductive titania nanofibres supporting Pt nanoparticles were synthesised in a one-pot method based on the electrospinning technique. The dimensions of both the oxide fibres and platinum particles were tuneable, leading to versatile nanomaterials with possible applications as electrodes for energy conversion devices.