Giant electrically tunable magnon transport anisotropy in a van der Waals antiferromagnetic insulator.

Anisotropy is a manifestation of lowered symmetry in material systems that have profound fundamental and technological implications. For van der Waals magnets, the two-dimensional (2D) nature greatly enhances the effect of in-plane anisotropy. However, electrical manipulation of such anisotropy as well as demonstration of possible applications remains elusive. In particular, in-situ electrical modulation of anisotropy in spin transport, vital for spintronics applications, has yet to be achieved. Here, we realized giant electrically tunable anisotropy in the transport of second harmonic thermal magnons (SHM) in van der Waals anti-ferromagnetic insulator CrPS4 with the application of modest gate current. Theoretical modeling found that 2D anisotropic spin Seebeck effect is the key to the electrical tunability. Making use of such large and tunable anisotropy, we demonstrated multi-bit read-only memories (ROMs) where information is inscribed by the anisotropy of magnon transport in CrPS4. Our result unveils the potential of anisotropic van der Waals magnons for information storage and processing.

Multichannel Single-Photon Emissions with On-Demand Momentums by Using Anisotropic Quantum Metasurfaces.

Photon momentums and their control are important for carrying quantum information and increasing information capacities. It is a great challenge to freely control multiple momentums of single photons based on only phase-dependent schemes in isotropic metasurfaces because exact manipulations of interference phases and precise alignments between quantum emitters and metasurfaces are involved. Here, an anisotropic metasurface, in which anisotropic rather than isotropic nanoscatterers are arranged anisotropically, is proposed to freely control multiple momentums of single photons. In the metasurfaces, the phase-independent and phase-dependent schemes are used to independently control spin angular momentums (SAMs) and linear momentums (LMs), respectively. The phase-independent scheme allows robust alignment between quantum emitters and metasurfaces. The anisotropic design amends geometrical phases for oblique emissions, providing larger ranges (up to 53°) for tailoring LMs. In experiments, three-channel single-photon emissions with independent SAMs and LMs are demonstrated. The introduction of anisotropic nanoscatterers and anisotropic arrangements of nanoscatterers is a more general design method for metasurfaces, and it could provide more flexibility to freely and efficiently tailor single-photon emissions.

Preparation of nanofibrous poly (L-lactic acid) scaffolds using the thermally induced phase separation technique in dioxane/polyethylene glycol solution.

Porous nanofibrous poly (L-lactic acid) (PLLA) scaffolds were fabricated in combination with a thermally induced phase separation technique using a dioxane/polyethylene glycol (PEG) system. The effect of factors such as molecular weight of PEG, aging treatment, aging or gelation temperature, and the ratio of PEG to dioxane were investigated. The results revealed that all scaffolds had high porosity, and had a significant impact on the formation of nanofibrous structures. The decrease in the molecular weight and aging or gelation temperature leads to a thinner and more uniform fibrous structure.

Specificity protein 1-mediated ACSL4 transcription promoted the osteoarthritis progression through suppressing the ferroptosis of chondrocytes.

BACKGROUND: Chondrocytes are the main cell damage type involved in the occurrence and development of osteoarthritis (OA). Ferroptosis has been confirmed to be related to many degenerative diseases. This research aimed to explore the role of Sp1 and ACSL4 in ferroptosis in the IL-1ß-treated human chondrocyte cells line (HCCs). METHODS: The cell viability was detected with CCK8 assay. The ROS, MDA, GSH, and Fe2+ levels were assessed with corresponding detecting kits. The Col2a1, Acan, Mmp13, Gpx4 and Tfr1 levels were determined by RT-qPCR assay. Western blot was conducted to evaluate the Acsl4 and Sp1 levels. PI staining was carried out to analyze the cell death. The double luciferase report was conducted to verify the interaction between Acsl4 and Sp1. RESULTS: The results showed that IL-1ß stimulation elevated the LDH release, cell viability, ROS, MDA and Fe2+ levels and declined the GSH levels in the HCCs. Additionally, the mRNA levels of Col2a1, Acan, and Gpx4 were prominently decreased, while Mmp13 and Tfr1 were prominently elevated in the IL-1ß stimulated HCCs. Furthermore, Acsl4 protein levels were upregulated in the IL-1ß-stimulated HCCs. Both Acsl4 knockdown and ferrostatin-1 treatment neutralized the role of IL-1ß in the HCCs. What's more, Acsl4 was transcriptionally regulated by Specificity protein 1 (Sp1). Sp1 overexpression enhanced the Acsl4 levels and Sp1 knockdown declined it. CONCLUSION: Upregulation of Sp1 activates Ascl4 transcription and thus mediates the occurrence of ferroptosis. Hence, Acsl4 may be a therapeutic target for intervention of OA.

Electrically switchable van der Waals magnon valves.

Van der Waals magnets have emerged as a fertile ground for the exploration of highly tunable spin physics and spin-related technology. Two-dimensional (2D) magnons in van der Waals magnets are collective excitation of spins under strong confinement. Although considerable progress has been made in understanding 2D magnons, a crucial magnon device called the van der Waals magnon valve, in which the magnon signal can be completely and repeatedly turned on and off electrically, has yet to be realized. Here we demonstrate such magnon valves based on van der Waals antiferromagnetic insulator MnPS3. By applying DC electric current through the gate electrode, we show that the second harmonic thermal magnon (SHM) signal can be tuned from positive to negative. The guaranteed zero crossing during this tuning demonstrates a complete blocking of SHM transmission, arising from the nonlinear gate dependence of the non-equilibrium magnon density in the 2D spin channel. Using the switchable magnon valves we demonstrate a magnon-based inverter. These results illustrate the potential of van der Waals anti-ferromagnets for studying highly tunable spin-wave physics and for application in magnon-base circuitry in future information technology.

LncRNA H19 Regulates Lipopolysaccharide (LPS)-Induced Apoptosis and Inflammation of BV2 Microglia Cells Through Targeting miR-325-3p/NEUROD4 Axis.

Spinal cord injury (SCI) is a devastating traumatic event worldwide. Work from the past decade has highlighted the key involvement of long non-coding RNAs (lncRNAs) in SCI. Nevertheless, the molecular action of lncRNA H19 in SCI is still not fully understood. The levels of H19, microRNA (miR)-325-3p, and neuronal differentiation 4 (NEUROD4) were determined by quantitative real-time polymerase chain reaction (qRT-PCR) or western blot. Flow cytometry was performed to assess cell apoptosis. The levels of tumor necrosis factor-α (TNF-α), interleukin 1ß (IL-1ß), and IL-6 were detected using the enzyme-linked immunosorbent assay (ELISA). Targeted relationships among H19, miR-325-3p, and NEUROD4 were confirmed by dual-luciferase reporter, RNA immunoprecipitation (RIP), or RNA pull-down assays. Our data showed that H19 level was overexpressed in lipopolysaccharide (LPS)-treated BV2 cells. H19 silencing alleviated LPS-evoked cell apoptosis and inflammation. Mechanistically, H19 in BV2 cells directly targeted miR-325-3p, and NEUROD4 was a direct target of miR-325-3p. Moreover, miR-325-3p was a functional target of H19 in regulating cell apoptosis and inflammation induced by LPS. Enforced expression of miR-325-3p relieved LPS-evoked cell apoptosis and inflammation through reducing NEUROD4. Furthermore, H19 in BV2 cells regulated NEUROD4 expression through targeting miR-325-3p. Our results identified that the silencing of H19 attenuated LPS-evoked microglia cell apoptosis and inflammation after SCI at least partially through targeting the miR-325-3p/NEUROD4 axis, highlighting a novel approach for SCI management.

Involvement of small G protein RhoB in the regulation of proliferation, adhesion and migration by dexamethasone in osteoblastic cells.

Long-term exposure to therapeutic doses of glucocorticoids (GCs) results in bone remodeling, which frequently causes osteoporosis and fracture healing retardation because of the abnormality of osteoblastic proliferation and differentiation. The mechanisms of GCs' effect on osteoblasts are largely unknown. In this present study, we found that dexamethasone (Dex) could induce the expression of the small G protein, RhoB, in mRNA and protein levels in the osteoblast-derived osteosarcoma cell lines MG-63. The up-regulation of RhoB mRNA by Dex mainly occurs at posttranscriptional level by increasing its mRNA stability through PI-3K/Akt and p38 mitogen-activated protein kinase signaling pathways. Over-expression of RhoB in MG-63 cells magnified while down-regulation of RhoB level by RNA interference impaired Dex-induced growth inhibition but not differentiation. What's more, over-expression of RhoB mimicked the effect of Dex on cell adhesion and migration. And interfering RhoB expression partially suppressed Dex-induced pro-adhesion and anti-migration in MG-63 cells. In conclusion, these results indicate that RhoB plays an important role in the pathological effect of Dex on osteoblastic growth and migration, which is a part of the mechanisms of GCs' adverse effect on bone remodeling.

Serum Sema4D levels are associated with lumbar spine bone mineral density and bone turnover markers in patients with postmenopausal osteoporosis.

To investigate the association of serum semaphorin 4D (Sema4D) levels with lumbar spine bone mineral density (BMD) and bone turnover markers in patients with postmenopausal osteoporosis (PO). Lumbar spine BMD was measured by dual-energy X-ray absorptiometry in 257 PO patients (aged from 50 to 75) and 90 healthy controls (aged from 51 to 83). Serum Sema4D, BAP, BGP and TRACP-5b levels were measured by enzyme linked immunosorbent assay. Serum cross linked N-telopeptides of type I (NTX), 25-hydroxyvitamin D (25(OH)D) and N-mid fragment of osteocalcin (N-MID-OT) levels were measured using automated electrochemiluminescence system. Sema4D level was significantly higher in PO women compared to healthy controls (1.40±0.33 vs. 0.58±0.18 µg/L, P=0.006). Sema4D level was positively correlated with serumTRACP-5b and NTX levels and negatively correlated with lumbar spine BMD and serum BAP and BGP levels. There were no correlations between Sema4D level and age, body mass index, and serum 25(OH)D and N-MID-OT levels. Lumbar spine BMD (ß=-0.354, P<0.001) and serum BAP level (ß=0.127, P=0.019) were independent predictors of serum Sema4D level in PO patients. Sema4D may be involved in the pathogenesis of PO and play a critical role in bone formation and resorption. Sema4D may represent a novel therapeutic target for treatment of PO and function as a predictive indicator of PO.

Large-diameter metal-on-metal cementless total hip arthroplasty in the elderly.

To evaluate the clinical effectiveness and complications of large-diameter metal-on-metal prostheses, particularly in the elderly, we performed cementless total hip arthroplasty (THA) using metal-on-metal prostheses with large-diameter femoral heads (mean, 45 mm) in 59 patients (average age, 75.1 years) between January 2004 and December 2005. All procedures were performed using a posterolateral approach and spinal anesthesia. Average follow-up was 65 months. Pre- and postoperative Harris Hip Scores and SF-36 questionnaire results were recorded for all patients to evaluate the level of pain relief, improvement in physical function, and changes in quality of life. Postoperative radiographic images were used to document areas of osteolysis and probable aseptic loosening. Average preoperative Harris Hip Score was 36.1±5.7, compared to 69.4±8.3 at last follow-up (P<.01). Average preoperative SF-36 score was 33.6±7.4, compared to 71.8±6.4 at last follow-up (P<.01). There were no dislocations, aseptic loosening, or revisions. Our findings suggest that metal-on-metal cementless prostheses with large-diameter femoral heads in THA can produce satisfactory results with good durability, a low rate of dislocation and aseptic loosening, and a low incidence of revisions in the short term. The benefits of this technique for elderly patients, especially those with weak muscle power and reduced cognitive function, include avoidance of severe cement-injection complications and early functional recovery.