Low-Temperature Nitrogen Doping in Ammonia Solution for Production of N-Doped TiO 2

To facilitate the potential application of TiO2 as an efficient photocatalyst, the modulation of its band gap and electrical structure is of great significance. Herein, we report a very simple nitrogen (N)-doping method to obtain N-doped TiO2, which is hybridized with graphene sheets at a temperature as low as 180 °C and using an ammonia solution as the N source and reaction medium. X-ray photoelectron spectroscopy analysis revealed that the atomic N level could reach 2.4 atomic percent when the reaction time was 14 h. Photoluminescence (PL) emission spectra indicated that N-doped TiO2/graphene composites have drastically suppressed TiO2 PL intensity when compared to undoped TiO2, confirming the lower recombination rate of electron–hole pairs in the N-doped TiO2. Additionally, photodegradation data showed that the decomposition rate of methylene blue with our N-doped TiO2/graphene photocatalyst is twice as fast as a commercial Degussa P25 catalyst. Furthermore, density functional theory (DFT) calculations demonstrate that N doping creates empty states in the band gap of the TiO2 that are below the Fermi energy of graphene. Thus, when N-doped TiO2 is brought into contact with graphene, these states become filled by electrons from the graphene, shifting the TiO2 bands upward relative to the graphene. Such a shift in band alignment across the TiO2/graphene heterojunction makes transfer of the photoexcited electron more energetically favorable. This work provides a very convenient chemical route to the scalable production of N-doped TiO2/graphene photocatalyst for potential applications in wastewater treatment

Fondaparinux in the initial and long-term treatment of venous thromboembolism

Background: Even in the absence of evidence on its long-term efficacy and safety, a number of patients with venous thromboembolism (VTE) receive long-term therapy with fondaparinux alone in everyday practice. Methods: We used the Registro Informatizado de Enfermedad Tromboembólica (RIETE) registry to compare the rate of VTE recurrences and major bleeding at 10 and 90 days in patients with and without cancer. For long-term therapy, fondaparinux was compared with vitamin K antagonists (VKA) in patients without cancer and with low-molecular- weight heparin (LMWH) in those with cancer Results Of 47,378 patients recruited, 46,513 were initially treated with heparin, 865 with fondaparinux. Then, 263 patients (78 with cancer) were treated for at least 3 months with fondaparinux. After propensity-score matching, there were no differences between patients receiving initial therapy with heparin or fondaparinux. Among patients with cancer, there were no differences between fondaparinux and LMWH. Among patients without cancer, the long-term use of fondaparinux was associated with an increased risk of major bleeding (3.24 % vs. 0.95 %, p < 0.05). Conclusions: An unexpected high rate of major bleeding was observed in non-cancer patients treated with longterm fondaparinux. Our small sample does not allowto derive relevant conclusions on the use of fondaparinux in cancer patients