Low-temperature anaerobic methane conversion to methanol (MTM) using copper ion-exchanged mordenite (Cu-MOR) as the catalyst and water as the sole source of oxygen is promising for sustainable utilization of methane. Integrating in situ calorimetric, spectroscopic, and structural methodologies, we report a systematic study on energetics of water−cationic species−framework guest−host interactions as a function of water loading for several mordenites relevant to low-temperature MTM. Notably, the near-zero coverage hydration enthalpy on Cu-MOR is −133.1 ± 6.0 kJ/mol water, which is related to Cu-MOR regeneration using water as oxidant. The copper oxo sites are thermally stable up to 915 °C and remain chemically intact as an oxygen source after complete hydration and dehydration. This study underscores the importance of manipulating the oxidation state and coordination chemistry of transition metal guest species in zeolites by fine-tuning the partial pressure of water as a strategy for rational design, synthesis, and modification of catalysts.
Vascular regeneration is a challenging topic in tissue repair. As one of the important components of the neurovascular unit (NVU), pericytes play an essential role in the maintenance of the vascular network of the spinal cord. To date, subtypes of pericytes have been identified by various markers, namely the PDGFR-β, Desmin, CD146, and NG2, each of which is involved with spinal cord injury (SCI) repair. In addition, pericytes may act as a stem cell source that is important for bone development and regeneration, whilst specific subtypes of pericyte could facilitate bone fracture and defect repair. One of the major challenges of pericyte biology is to determine the specific markers that would clearly distinguish the different subtypes of pericytes, and to develop efficient approaches to isolate and propagate pericytes. In this review, we discuss the biology and roles of pericytes, their markers for identification, and cell differentiation capacity with a focus on the potential application in the treatment of SCI and bone diseases in orthopedics.
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