RESUMEN
Recent debates on the oxygen redox behaviors in battery electrodes have triggered a pressing demand for the reliable detection and understanding of nondivalent oxygen states beyond conventional absorption spectroscopy. Here, enabled by high-efficiency mapping of resonant inelastic X-ray scattering (mRIXS) coupled with first-principles calculations, we report distinct mRIXS features of the oxygen states in Li2O, Li2CO3, and especially, Li2O2, which are successfully reproduced and interpreted theoretically. mRIXS signals are dominated by valence-band decays in Li2O and Li2CO3. However, the oxidized oxygen in Li2O2 leads to partially unoccupied O-2p states that yield a specific intraband excitonic feature in mRIXS. Such a feature displays a specific emission energy in mRIXS, which disentangles the oxidized oxygen states from the dominating transition-metal/oxygen hybridization features in absorption spectroscopy, thus providing critical hints for both detecting and understanding the oxygen redox reactions in transition-metal oxide based battery materials.
RESUMEN
PURPOSE: To investigate the method and conditions of isolation and proliferation of multipotent mesenchymal stem cells (MSCs) from human maxillary sinus membrane in vitro and to induce osteogenic differentiation directly for identification. MATERIALS AND METHODS: A human maxillary sinus membrane specimen was collected in aseptic conditions from an orthognathic surgery patient and cultured. The cells at passage three were sorted by flow cytometry and treated with osteogenic differentiation media. To determine the osteogenic potential of these cells, the authors analyzed alkaline phosphatase (ALP) expression, mineralization of extracellular matrix, and osteocalcin expression; staining with alizarin red and von Kossa and reverse-transcriptase polymerase chain reaction were also performed. RESULTS: Maxillary sinus membrane-derived cells were positive for STRO-1 and CD105 and negative for CD34. After 7 days, ALP began to be expressed. After 21 and 28 days, most cells showed expression of ALP. Mineralization of the extracellular matrix was observed and, after 21 and 28 days, most of the cells showed mineralization. After 7 days, the osteocalcin gene was expressed; this expression was strongest on the 28th day. CONCLUSIONS: The results suggest that there are MSCs in human maxillary sinus membrane tissue, which can be differentiated into osteoblasts under osteogenic induction. This indicates that maxillary sinus membrane may be a useful source of MSCs for cell therapy.
