Electronic structures of single crystalline black phosphorus were studied by state-of-art angleresolved photoemission spectroscopy. Through high resolution photon energy dependence measurements, the band dispersions along out-of-plane and in-plane directions are experimentally determined. The electrons were found to be more localized in the ab-plane than that is predicted in calculations. Beside the kz-dispersive bulk bands, resonant surface state is also observed in the momentum space. Our finds strongly suggest that more details need to be considered to fully understand the electronic properties of black phosphorus theoretically.

Non-symmorphic crystals are generating great interest as they are commonly found in quantum materials, like iron-based superconductors, heavy-fermion compounds, and topological semimetals. A new type of surface state, a floating band, was recently discovered in the nodal-line semimetal ZrSiSe, but also exists in many non-symmorphic crystals. Little is known about its physical properties. Here, we employ scanning tunneling microscopy to measure the quasiparticle interference of the floating band state on ZrSiSe (001) surface and discover rotational symmetry breaking interference, healing effect and half-missing-type anomalous Umklapp scattering. Using simulation and theoretical analysis we establish that the phenomena are characteristic properties of a floating band surface state. Moreover, we uncover that the half-missing Umklapp process is derived from the glide mirror symmetry, thus identify a non-symmorphic effect on quasiparticle interferences. Our results may pave a way towards potential new applications of nanoelectronics.

Hereditary spinocerebellar ataxia (SCA) is a devastating, incurable disease. Stem-cell-based therapies represent new promise for clinical research in neurology. The objectives of this study were to assess the feasibility, efficacy, and potential toxicity of human umbilical cord mesenchymal stem cells (UCMSCs) therapy in patients with SCA. Sixteen genomically diagnosed SCA patients were enrolled and received intravenous and intrathecal infusion of UCMSCs. Clinical, laboratory, and radiographic evaluations were conducted to assess the safety of UCMSC therapy. Efficacy was evaluated by the Berg Balance Scale (BBS) and International Cooperative Ataxia Rating Scale (ICARS) scores. Among the 16 cases, there were no serious transplant-related adverse events happened in 12 months follow-up. The majority of patients showed improved BBS and ICARS scores continuing for at least 6 months which indicated UCMSC therapy could alleviate SCA symptoms. This study suggested that UCMSC transplantation was safe and might delay the progression of SCA. This may represent a new therapeutic strategy for SCA and other genetic neurological diseases.