Approaching quantum anomalous Hall effect in proximity-coupled YIG/graphene/h-BN sandwich structure

Quantum anomalous Hall state is expected to emerge in Dirac electron systems such as graphene under both sufficiently strong exchange and spin-orbit interactions. In pristine graphene, neither interaction exists; however, both interactions can be acquired by coupling graphene to a magnetic insulator (MI) as revealed by the anomalous Hall effect. Here, we show enhanced magnetic proximity coupling by sandwiching graphene between a ferrimagnetic insulator yttrium iron garnet (YIG) and hexagonal-boron nitride (h-BN) which also serves as a top gate dielectric. By sweeping the top-gate voltage, we observe Fermi level-dependent anomalous Hall conductance. As the Dirac point is approached from both electron and hole sides, the anomalous Hall conductance reaches 1/4 of the quantum anomalous Hall conductance 2e2/h. The exchange coupling strength is determined to be as high as 27 meV from the transition temperature of the induced magnetic phase. YIG/graphene/h-BN is an excellent heterostructure for demonstrating proximity-induced interactions in two-dimensional electron systems

Anterolateral thigh perforator flap made by customized 3D-printing fabrication of fixed positioning guide for oromaxillofacial reconstruction:a preliminary study

Oromaxillofacial carcinomas frequently result in serious tissue defect due to enlarged resection for treating their extensive invasion, which require challenging reconstruction. Three-dimensional (3D) printing is an advanced technology which has greatly promoted the progress of craniomaxillofacial reconstructive surgery. This present study aimed to investigate the advantages of anterolateral thigh (ALT) perforator flap manufactured by 3D printing fixed positioning guide template in curing oromaxillofacial defect. Twenty patients with oromaxillofacial defects resulted from severe primary malignant tumors were divided into experimental group assisted by digital technique (n=8) and controlled group conventionally aided by ultrasound (n=12). The therapeutic effectiveness, flap preparation time, amount of bleeding, deviation of perforator vessel location, aesthetic satisfaction of donor site, postoperative complications, adverse symptom of flap, and LEFS scores were compared. For experimental group, flap preparation time was significantly shorter; and it has obviously less bleeding, minor deviation of perforator vessel location, and better aesthetic satisfaction of donor site (P.05). The study suggests 3D printing template of fixed positioning guide provides a brand-new method for orienting perforated vessels of ALT flap, which is more accurate in clinical application. It can improve the operative efficacy, and increase the successful rate of operation as well

The effect of mesoporous bioglass on osteogenesis and adipogenesis of osteoporotic BMSCs

This study evaluated the effect of mesoporous bioglass (MBG) dissolution on the differentiation of bone marrow mesenchymal stem cells (BMSCs) derived from either sham control or ovariectomized (OVX) rats. MBG was fabricated by evaporation-induced self-assembly method. Cell proliferation was tested by Cell Counting Kit-8 assay, and cytoskeletal morphology was observed by fluorescence microscopy. Osteogenic differentiation was evaluated by alkaline phosphatase (ALP) staining and activity, Alizarin Red staining, while adipogenic differentiation was assessed by Oil Red-O staining. Quantitative real-time PCR and Western blot analysis were taken to evaluate the expression of runt-related transcription factor 2 (Runx2) and proliferator-activated receptor-γ (PPARγ). We found that MBG dissolution (0, 25, 50, 100, 200 µg/mL) was nontoxic to BMSCs growth. Sham and OVX BMSCs exhibited the highest ALP activity in 50 µg/mL of MBG osteogenic dissolution, except that sham BMSCs in 100 µg/mL showed the highest ALP activity on day 14. Runx2 was significantly upregulated after 100 µg/mL of MBG stimulation in sham and OVX BMSCs for 7 and 14 days, except that 25 µg/mL showed highest upregulation effect on OVX BMSCs at day 7. PPARγ was downregulated after MBG stimulation. The protein level of Runx2 from the sham BMSCs group was significantly upregulated after lower doses (25 and 50 µg/mL) of MBG stimulation, whereas PPARγ was downregulated in the sham and OVX BMSCs group. Thus, both the osteogenic and adipogenic abilities of BMSCs were damaged under OVX condition. Moreover, lower concentration of MBG dissolution can promote osteogenesis but inhibit adipogenesis of the sham and OVX BMSCs