The edge engineering of topological Bi(111) bilayer

A topological insulator is a novel quantum state, characterized by symmetry-protected non-trivial edge/surface states. Our first-principle simulations show the significant effects of the chemical decoration on edge states of topological Bi(111) bilayer nanoribbon, which remove the trivial edge state and recover the Dirac linear dispersion of topological edge state. By comparing the edge states with and without chemical decoration, the Bi(111) bilayer nanoribbon offers a simple system for assessing conductance fluctuation of edge states. The chemical decoration can also modify the penetration depth and the spin texture of edge states. A low-energy effective model is proposed to explain the distinctive spin texture of Bi(111) bilayer nanoribbon, which breaks the spin-momentum orthogonality along the armchair edge.Comment: 5 pages, 5 figure

4,4′-Di-3-pyridyl-2,2′-dithio­dipyrimidine

The asymmetric unit of the title compound, C18H12N6S2, contains one half-mol­ecule situated on a twofold rotational axis that passes through the mid-point of the S—S bond. In the mol­ecule, the C—S—S—C torsion angle is 81.33 (7)°. The crystal packing exhibits no significantly short inter­molecular contacts

(S)-1-[3,5-Bis­(trifluoro­meth­yl)phen­yl]-N-methylethyl­amine–(R)-2-hydroxy­butane­dioic acid (1/1)

In the title compound, C11H11F6N·C4H6O5, a key inter­mediate in the synthesis of the NK1 receptor antagonist of casopitant, the F atoms of the trifluoro­methyl groups are disordered over two sites with equal occupancies. In the crystal, the components are linked by bifurcated N—H⋯(O,O) hydrogen bonds

The Online Data Quality Monitoring System at BESIII

The online Data Quality Monitoring (DQM) plays an important role in the data taking process of HEP experiments. BESIII DQM samples data from online data flow, reconstructs them with offline reconstruction software, and automatically analyzes the reconstructed data with user-defined algorithms. The DQM software is a scalable distributed system. The monitored results are gathered and displayed in various formats, which provides the shifter with current run information that can be used to find problems early. This paper gives an overview of DQM system at BESIII.Comment: Already submit to Chinese Physics

3-{[4-(4-Pyrid­yl)pyrimidin-2-yl]sulfanylmeth­yl}benzoic acid

The title compound, C17H13N3O2S, was prepared by reaction of 4-(4-pyrid­yl)pyrimidine-2-thiol with 3-(bromo­meth­yl)benzoic acid under basic conditions. Each pair of mol­ecules is mutually linked via O—H⋯N hydrogen bonds, forming a dimer. The packing of the dimers is stablized by C—H⋯π inter­actions involving the methyl­ene unit of the –CH2S– linkage and benzene rings

{Bis[4-(2-pyrid­yl)pyrimidin-2-yl]sulfane}dichloridocobalt(II)

The asymmetric unit of the title compound, [CoCl2(C18H12N6S)], contains one half-mol­ecule situated on a twofold rotation axis which passes through the Co and S atoms. The metal centre is in a distorted octahedral CoCl2N4 coordination with the Cl atoms in the axial positions. In the crystal structure, inter­molecular C—H⋯Cl inter­actions help to establish the packing

Efficacy of different approaches of spinal endoscopy in the treatment of L 4-5 intervertebral disc herniation

Objective To compare the clinical efficacy of two approaches under spinal endoscopy in the treatment of L 4-5 intervertebral disc herniation. Methods A retrospective analysis was performed for 148 patients with L 4-5 intervertebral disc herniation treated in The Affiliated Huai'an No.1 People's Hospital of Nanjing Medical University from January 2020 to June 2023. Among them, 68 cases were treated with percutaneous endoscopic transforaminal discectomy (PETD group), and 80 cases were treated with percutaneous endoscopic interlaminar discectomy (PEID group). Surgical time, intraoperative fluoroscopy frequency, intraoperative bleeding volume, postoperative hospital stay, and clinical efficacy were compared between two groups. Preoperative and postoperative lumbar Oswestry dysfunction index (ODI), VAS score for lower back and leg pain were compared. Results Patients in both groups were followed up for 6-36 months, with an average of 21.6 month. The surgical time, intraoperative bleeding volume, postoperative hospital stay, and intraoperative fluoroscopy in the PEID group were significantly lower than those in the PETD group (P＜0.05). The VAS scores of lower back and leg pain and ODI scores in the two groups at the first day, one month, three months and the last follow-up after operation were improved compared with those before operation (P＜0.05), but there was no significant difference between the two groups (P＞0.05). There was no significant difference in the excellent and good rate between the PETD group and PEID group (95.6% vs 93.8%, χ2=0.016, P=0.898). Conclusion Both approaches under spinal endoscopy can effectively treat L 4-5 intervertebral disc herniation, but the PEID group has shorter operation time and fewer fluoroscopic times, which can effectively shorten the operation time and anesthesia time

Ultrahydrophobicity of Polydimethylsiloxanes-Based Multilayered Thin Films

The formation of polydimethylsiloxanes (PDMSs)-based layer-by-layer multilayer ultrathin films on charged surfaces prepared from water and phosphate buffer solutions has been investigated. The multilayer films prepared under these conditions showed different surface roughness. Nanoscale islands and network structures were observed homogeneously on the multilayer film prepared from pure water solutions, which is attributing to the ultrahydrobic property of the multilayer film. The formation of nanoscale islands and network structures was due to the aggregation of PDMS-based polyelectrolytes in water. This work provides a facile approach for generating ultrahydrophobic thin films on any charged surfaces by PDMS polyelectrolytes