We report a joint experimental−computational mechanistic study of electrochemical reduction of CO 2 to CH 4 , catalyzed by solid-state Fe−N−C catalysts, which feature atomically dispersed, catalytically active Fe−N x sites and represent one of the very rare examples of solid, non-Cu-based electrocatalysts that yield hydrocarbon products. Work reported here focuses on the identification of plausible mechanistic pathways from CO 2 to various C 1 products including methane. It is found that Fe−N x sites convert only CO 2 , CO, and CH 2 O into methane, whereas CH 3 OH appears to be an end product. Distinctly different pH dependence of the catalytic CH 4 evolution from CH 2 O in comparison with that of CO 2 and CO reduction indicates differences in the proton participation of ratedetermining steps. By comparing the experimental observations with density functional theory derived free energy diagrams of reactive intermediates along the CO 2 reduction reaction coordinates, we unravel the dominant mechanistic pathways and roles of CO and CH 2 O during the catalytic CO 2 -to-CH 4 cascades and their rate-determining steps. We close with a comprehensive reaction network of CO 2 RR on single-site Fe−N−C catalysts, which may prove useful in developing efficient, non-Cubased catalysts for hydrocarbon production.

This is a correlation analysis between severity of the ossification of the nuchal ligament (ONL) and clinical cervical disorders including neck dysfunction, cervical malalignment, and morphologic changes of the cervical neural foramen (CNF). The clinical effects of ONL on active range of motion (AROM) of neck, cervical radiculopathy, abnormal cervical curvature, and the degree of CNF stenosis in patients with painful neck stiffness are investigated. Studies have investigated the predisposing factors to cervical dysfunction and degenerative disorders; however, few studies have examined the influence of the ONL on neck function and cervical spine. A total of 31 participants with painful neck stiffness were recruited. They accepted measurement of cervical AROM and serial cervical radiographs at anterior-posterior view, lateral view, and bilateral oblique views. Parameters of radiographs measurement included cervical lordotic curve, and cross-sectional areas (CSA) of the ONL and CNF (C2-C3, C4-C5, C5-C6, and C6-C7 levels). The ratio of CSA of the lower CNF (C4-C5, C5-C6, C6-C7) to CSA of the upper CNF (C2-C3) was used as a CNF stenosis ratio. The correlations of ONL size, neck symptoms, cervical AROM, lordotic curve, and CNF stenosis ratio were analyzed. More than half of all patients were positive in cervical root signs and prone to have larger ONL. Neck AROM of all participants was significantly below normal average in all directions, and a moderate negative association was found between the ONL CSA and AROM in flexion-extension. Most patients had moderate loss of cervical lordotic curve despite there being no significant correlation between ONL CSA and cervical curvature. Moreover, CNF stenosis ratio significantly negatively correlated with ONL CSA. Patients with larger ONL had more severe cervical radiculopathy, more stiffness in flexion-extension direction, more complex degenerative change of spine, and worse CNF stenosis.

Temperature-controlled intermolecular desulfonylative condensation of α-sulfonyl o-hydroxyacetophenones with 2-formyl azaarenes (pyridines and quinolones) provides azaaryl (pyridyl and quinolyl) aurones and flavones under warming and refluxing toluene reaction conditions via the formation of the intermediate of sulfonyl chroman-4-one. The uses of various solvents are investigated for facile and efficient transformation. A plausible mechanism is proposed.

A convenient synthetic route for the construction of functionalized 2-cyano-1,4-diketones has been established from the nucleophilic substitution of 2-bromoacetophenones with NaCN via the in situ-generated β-ketonitriles. This method was further applied to the synthesis of cyanosubstituted furans, pyrroles, or dihydropyridazines, which were obtained in good to excellent yields using Bi(OTf)3, NH4OAc, or N2H4. The key structures were confirmed by X-ray single crystal diffraction analysis.