Proposed Quantum Twisting Scanning Probe Microscope over Twisted Bilayer Graphene.

Twisted bilayer graphene (TBG) has the natural merits of tunable flat bands and localized states distributed as a triangular lattice. However, the application of this state remains obscure. By density functional theory (DFT) and pz orbital tight-binding model calculations, we investigate the tip-shaped electrostatic potential of top valence electrons of TBG at half filling. Adsorption energy scanning of molecules above the TBG reveals that this tip efficiently attracts molecules selectively to AA-stacked or AB-stacked regions. Tip shapes can be controlled by their underlying electronic structure, with electrons of low bandwidth exhibiting a more localized feature. Our results indicate that TBG tips offer applications in noninvasive and nonpolluting measurements in scanning probe microscopy and theoretical guidance for 2D material-based probes.

Remote-Triggered Domino-like Cyclodehydrogenation in Second-Layer Topological Graphene Nanoribbons.

Cyclodehydrogenation reactions in the on-surface synthesis of graphene nanoribbons (GNRs) usually involve a series of Csp2-Csp2 and/or Csp2-Csp3 couplings and just happen on uncovered metal or metal oxide surfaces. It is still a big challenge to extend the growth of second-layer GNRs in the absence of necessary catalytic sites. Here, we demonstrate the direct growth of topologically nontrivial GNRs via multistep Csp2-Csp2 and Csp2-Csp3 couplings in the second layer by annealing designed bowtie-shaped precursor molecules over one monolayer on the Au(111) surface. After annealing at 700 K, most of the polymerized chains that appear in the second layer covalently link to the first-layer GNRs that have partially undergone graphitization. Following annealing at 780 K, the second-layer GNRs are formed and linked to the first-layer GNRs. Benefiting from the minimized local steric hindrance of the precursors, we suggest that the second-layer GNRs undergo domino-like cyclodehydrogenation reactions that are remotely triggered at the link. We confirm the quasi-freestanding behaviors in the second-layer GNRs by measuring the quasiparticle energy gap of topological bands and the tunable Kondo resonance from topological end spins using scanning tunneling microscopy/spectroscopy combined with first-principles calculations. Our findings pave the avenue to diverse multilayer graphene nanostructures with designer quantum spins and topological states for quantum information science.

Photochemical reaction of glucocorticoids in aqueous solution: Influencing factors and photolysis products.

Glucocorticoids (GCs), as endocrine disruptors, have attracted widespread attention due to their impacts on organisms' growth, development, and reproduction. In the current study, the photodegradation of budesonide (BD) and clobetasol propionate (CP), as targeted GCs, was investigated including the effects of initial concentrations and typical environmental factors (Cl-, NO2-, Fe3+, and fulvic acid (FA)). The results showed that the degradation rate constants (k) were 0.0060 and 0.0039 min-1 for BD and CP at concentration of 50 µg·L-1, and increased with the initial concentrations. Under the addition of Cl-, NO2-, and Fe3+ to the GCs/water system, the photodegradation rate was decreased with increasing Cl-, NO2-, and Fe3+ concentrations, which were in contrast to the addition of FA. Electron resonance spectroscopy (EPR) analysis and the radical quenching experiments verified that GCs could transition to the triplet excited states of GCs (3GCs*) for direct photolysis under irradiation to undergo, while NO2-, Fe3+, and FA could generate ·OH to induce indirect photolysis. According to HPLC-Q-TOF MS analysis, the structures of the three photodegradation products of BD and CP were elucidated, respectively, and the phototransformation pathways were inferred based on the product structures. These findings help to grasp the fate of synthetic GCs in the environment and contribute to the understanding of their ecological risks.

Corrigendum: Case report: dual primary malignancies treated by laparoscopic multiorgan resection with natural orifice specimen extraction surgery.

[This corrects the article DOI: 10.3389/fonc.2022.916104.].

Case report: dual primary malignancies treated by laparoscopic multiorgan resection with natural orifice specimen extraction surgery.

With microtrauma becoming a consensus, in order to improve surgical treatment capability, the clinical application of laparoscopic multiorgan resection is becoming more and more complicated and diversified. Recently, we successfully presented a case of transvaginal specimen extraction surgery that included laparoscopic anatomical left hemihepatectomy combined with laparoscopic total hysterectomy and bilateral adnexectomy and the pelvic and para-aortic lymphadenectomy. The patient, a 75-year-old woman, was hospitalized with abnormal vaginal discharge and bleeding. The pathologic diagnosis of uterine curettage was endometrioid adenocarcinoma. After completing examinations such as color Doppler ultrasound, CEUS, MRCP and thoracoabdominal enhanced spiral CT, preoperative diagnosis was considered as endometrial cancer and a space-occupying lesion in the liver (primary or secondary site)?. No lymphatic or distant metastasis had been found. We also excluded Lynch syndrome by digestive endoscopy and gene sequencing. After a multidisciplinary consultation, the patient underwent surgery under general anesthesia on 24 September 2021. The operation was completed uneventfully in 6 hours, then the patient was transferred to the ICU for follow-up monitoring. The patient began to eat and was able to leave bed on the 4th postoperative day. According to immunohistochemistry, the patient's postoperative diagnosis was intrahepatic cholangiocarcinoma (ICC) and endometrial cancer. Compared with open surgery, laparoscopic multiorgan resection with natural orifice specimen extraction surgery (NOSES) has many advantages such as fewer traumas, shorter recovery time, and better postoperative quality of life. However, combined large-scale laparoscopic surgeries of different organs can be challenging for surgeons and anesthesiologists. No similar cases have been searched.

Effects of Different Treatment of Fecal Microbiota Transplantation Techniques on Treatment of Ulcerative Colitis in Rats.

Background: Ulcerative colitis (UC) is a chronic non-specific inflammatory bowel disease with abdominal pain, mucus, pus and blood in the stool as the main clinical manifestations. The pathogenesis of UC is still not completely clear, and multiple factors, such as genetic susceptibility, immune response, intestinal microecological changes and environmental factors, together lead to the onset of UC. In recent years, the role of intestinal microbiota disturbances on the pathogenesis of UC has received widespread attention. Therefore, fecal microbiota transplantation (FMT), which changes the intestinal microecological environment of UC patients by transplantation of normal fecal bacteria, has attracted increasing attention from researchers. However, there are no guidelines to recommend fresh FMT or frozen FMT in the treatment of UC, and there are few studies on this. Therefore, the purpose of this study was to explore the effects of fresh and frozen FMT methods on the treatment of experimental UC models in rats. Results: Compared with the model control group, all FMT groups achieved better efficacy, mainly manifested as weight gain by the rats, improvements in fecal characteristics and blood stools, reduced inflammatory factors and normal bacterial microbiota. The efficacy of the frozen FMT group was better than that of the fresh FMT group in terms of behavior and colon length. Conclusion: FMT method supplements the gut microbiota with beneficial bacteria, such as short-chain fatty acid-producing bacteria. These bacteria can regulate intestinal function, protect the mucosal barrier and reduce harmful bacteria, thus mitigating the damage to the intestinal barrier and the associated inflammatory response, resulting in UC remission. FMT is a feasible method for treating UC, with frozen FMT having a superior therapeutic effect than that of fresh FMT.