RESUMO
Metal nanocrystals (NCs) are grown directly on the surface of reduced graphene oxide (rGO), which can maximize the rGO-NCs contact/interaction to achieve the enhanced catalytic activity. However, it is difficult to control the size and morphology of metal NCs by in situ method due to the effects of functional groups on the surface of GO, and as a result, the metal NCs/rGO hybrids are conventionally synthesized by two-step method. Herein, one-pot synthesis of Pt-Co alloy NCs is demonstrated with concave-polyhedrons and concave-nanocubes bounded by {hkl} and {hk0} high-index facets (HIFs) distributed on rGO. GO can affect the geometry and electronic structure of Pt-Co NCs. Thanks to the synergy of the HIFs and the electronic effect of the intimate contact/interaction between Pt-Co alloy and rGO, these as-prepared Pt-Co NCs/rGO hybrids presents enhanced catalytic properties for the electrooxidation of formic acid, as well as for the oxygen reduction reaction.
RESUMO
BACKGROUND: Spinal neurosyphilis manifesting as a solitary syphilitic gumma is exceedingly rare. There are non-specific imaging findings and challenges in the diagnosis of spinal syphilitic gumma, which could be easily misdiagnosed as tumor lesions and require surgical resection or biopsy. CLINICAL PRESENTATION: We report the case of a 45-year-old female patient who was diagnosed with Spinal syphilitic gumma. Our case is the first reported case of spinal cord syphilitic gumma with intradural-extramedullary and intramedullary involvement. CONCLUSION: Spinal syphilitic gumma exhibits diverse clinical manifestations, lacks specific imaging features, accompanied by the patient's history deliberately concealed. Since clinicians do not have sufficient knowledge about such rare cases, misdiagnosis and missed diagnosis will be likely. When there is clinical suspicion for spinal syphilitic gumma, clinicians should pay close attention to relevant medical history, carry out a comprehensive physical examination and specific serological tests and cerebrospinal fluid (CSF) analysis. In summary, in cases with stable neurologic conditions, a trial administration of intravenous penicillin with follow-up imaging may be the optimal treatment option, and in cases with rapid progression or acute exacerbation, a surgical resection together with systemic antibiotic treatment for syphilis after surgery may be the best treatment strategy.