Anterior debridement combined with autogenous iliac bone graft fusion for the treatment of lower cervical tuberculosis: a multicenter retrospective study.

BACKGROUND: This study aimed to analyze the clinical efficacy of one-stage anterior debridement of lower cervical tuberculosis using iliac crest bone graft fusion and internal fixation. MATERIALS AND METHODS: A retrospective analysis was performed on 48 patients with lower cervical tuberculosis admitted to multiple medical centers from June 2018 to June 2021. Among them, 36 patients had lesions involving two vertebrae and 12 patients had lesions involving more than three vertebrae. All patients were treated with quadruple antituberculosis drugs for more than 2 weeks before the operation, and then treated with one-stage anterior debridement and autogenous iliac bone graft fusion combined with titanium plate internal fixation. After the operation, antituberculosis drugs were continued for 12-18 months. The patients were followed-up to observe the improvement in clinical symptoms, bone graft fusion, Cobb angle, visual analog score (VAS), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), wound healing, and neurological function. RESULTS: The patients were followed-up for 13-43 months, with an average of 21.46 ± 1.52 months. The clinical symptoms significantly improved after the operation. The bone graft was completely fused in all patients, and the bone fusion time was 3-6 months, with an average of 4.16 ± 0.47 months. At the last follow-up, the Cobb angle, VAS, ESR, and CRP level were significantly lower than those before surgery (P < 0.05). None of the patients had loosening, detachment, or rupture of the internal fixation, and no recurrence occurred. All surgical incisions healed in one stage without infection or sinus formation. The preoperative Frankel neurological function classification was grade B in 7 cases, grade C in 13, grade D in 18, and grade E in 10. At the last follow-up, 8 cases recovered to grade D and 40 recovered to grade E. CONCLUSIONS: For patients with lower cervical tuberculosis, based on oral treatment with quadruple antituberculosis drugs, direct decompression through anterior debridement, followed by autologous iliac bone graft fusion combined with internal fixation can completely remove tuberculosis foci, rebuild the stability of the cervical spine, and obtain good clinical efficacy. Level of evidence Level 3.

Isolation and characterization of novel process-related impurities in empagliflozin.

Empagliflozin is an effective sodium glucose cotransporter-2 (SGLT2) inhibitor to improve glycemic control in adults with type 2 diabetes. During the manufacture of empagliflozin, three unknown impurities were discovered in pilot batches ranging from 0.05 % to 0.15 % by LC analysis. These unknown impurities were isolated from the crystallization mother liquor by column chromatography and semi-preparative LC, and their structures were elucidated by comprehensive analysis of HRMS, 1D-NMR (1H, 13C) and 2D-NMR (1H-1H COSY, HSQC, HMBC) spectroscopy data. The plausible mechanistic pathways to the formation of these three impurities were also discussed.

Observation of Topological Edge States on α-Bi4Br4 Nanowires Grown on TiSe2 Substrates.

A time-reversal invariant two-dimensional (2D) topological insulator (TI) is characterized by the gapless helical edge states propagating along the perimeter of the system. However, the small band gap in the 2D TIs discovered so far hinders their applications. Recently, we predicted that single-layer Bi4Br4 is a 2D TI with a remarkable band gap and that α-Bi4Br4 crystals can host topological edge states at the step edges. Here we report the growth of α-Bi4Br4 nanowires with (102)-oriented top surfaces on the TiSe2 substrates and the direct observation of the predicted topological edge states at the step edges of the nanowires using scanning tunneling microscopy. The coupling between the edge states leads to the formation of surface states at the (102) top surfaces of the nanowires. Our work demonstrates the existence of topological edge states in α-Bi4Br4 and paves the way for developing α-Bi4Br4-based devices for a high-temperature quantum spin Hall effect.

Epitaxial growth of Bi(110) and Bi2Se3thin films on a ferromagnetic insulator substrate of Cr2Ge2Te6.

When a topological insulator (TI) is brought to the proximity of a ferromagnetic insulator (FMI), the breaking of the time-reversal symmetry may give rise to quantum anomalous Hall effect (QAHE). The physical properties of such TI-FMI systems are greatly affected by the interfacial structures of the components. Here, we report the growth and structural properties of Bi(110) and Bi2Se3thin films on a FMI of Cr2Ge2Te6(CGT) substrate by scanning tunneling microscopy. We observed various defects and impurities on the CGT surfaces, which serve as the preferential sites for initial nucleation and epitaxial growth of Bi(110) thin films. The exposure of the as-grown Bi(110) thin films to Se vapor leads to the formation of polycrystalline Bi2Se3thin films with randomly distributed holes. The structure and composition of the as-prepared Bi2Se3thin films were further confirmed by Raman spectroscopy and x-ray photoelectron spectroscopy. Our work shows that the quality of the CGT crystals is vital for the growth of high-quality TIs on CGT substrates for QAHE.

Magnetic and electric properties of single crystal MnI2.

Multiferroic materials endowed with both dielectric and magnetic orders, are ideal candidates for a wide range of applications. In this work, we reported two phase transitions of MnI2 at 3.45 K and 4 K by systemically measuring the magnetic-field and temperature-dependent magnetization of the MnI2 thin flakes. Furthermore, we observed similar temperature and field-dependent behaviours for the magnetic susceptibility of MnI2 and electronic capacitance of the Ag/MnI2/Ag devices below 3.5 K. Considering the related theory work, we discussed the relationship between the antiferromagnetic and ferroelectric orders in MnI2. Our work reveals the in-plane magnetic and electric properties of MnI2 materials, which might be helpful for the further investigation and application of MnI2 multiferroics in the future.

Observation of Topological Edge States at the Step Edges on the Surface of Type-II Weyl Semimetal TaIrTe4.

Topological materials harbor topologically protected boundary states. Recently, TaIrTe4, a ternary transition-metal dichalcogenide, was identified as a type-II Weyl semimetal with the minimal nonzero number of Weyl points allowed for a time-reversal invariant Weyl semimetal. Monolayer TaIrTe4 was proposed to host topological edge states, which, however, lacks of experimental evidence. Here, we report on the topological edge states localized at the monolayer step edges of the type-II Weyl semimetal TaIrTe4 using scanning tunneling microscopy. One-dimensional electronic states that show substantial robustness against the edge irregularity are observed at the step edges. Theoretical calculations substantiate the topologically nontrivial nature of the edge states and their robustness against the edge termination and layer stacking. The observation of topological edge states at the step edges of TaIrTe4 surfaces suggests that monolayer TaIrTe4 is a two-dimensional topological insulator, providing TaIrTe4 as a promising material for topological physics and devices.