No abstract

Osteoporosis poses substantial challenges for biomaterials implantation. New approaches to improve bone‐implant integration should resolve the fundamental dilemma of inflammation—proper inflammation is required at early stages but should be suppressed later for better healing, especially under osteoporosis. However, precisely switching on and off inflammation around implants in vivo remains unachieved. To address this challenge, a “bridge‐burning” coating material that comprises a macrophage‐activating glycan covalently crosslinked by a macrophage‐eliminating bisphosphonate to titanium implant surface is designed. Upon implantation, the glycan instructs host macrophages to release pro‐osteogenic cytokines (“switch‐on”), promoting bone cell differentiation. Later, increasingly mature bone cells secrete alkaline phosphatase to cleave the glycan‐bisphosphonate complexes from the implant, which in turn selectively kill the proinflammatory macrophages (“switch‐off”) that have completed their contribution—hence in the manner of “burning bridges”—to promote healing. In vivo examination in an osteoporotic rat model demonstrates that this coating significantly enhances bone‐implant integration (88.4% higher contact ratio) through modulating local inflammatory niches. In summary, a bioresponsive, endogenously triggered, smart coating material is developed to sequentially harness and abolish the power of inflammation to improve osseointegration under osteoporosis, which represents a new strategy for designing immunomodulatory biomaterials for tissue regeneration.

A 28 GHz millimeter-wave (mm-wave) propagation measurement campaign was performed to predict the multiple-input multiple-output (MIMO) channel performance in a tunnel environment. Two kinds of polarization configurations were studied in this paper. In order to overcome the serious path loss (PL) of mm-wave propagation, a high gain directional horn antenna was used in the measurements of tunnel environment. The measurement results and simulation results at same specific locations are compared. The result of comparison indicates that the simulation model matches the measurement well. Then the MIMO capacity at other locations of the tunnel can be predicted by the simulation model. Furthermore , it is inferred that the antenna array elements of horizontally polarized configuration have higher capacity than the vertically polarized under the constant signal-to-noise ratio (SNR). INDEX TERMS Channel, multiple-input multiple-output (MIMO), millimeter-wave (mm-wave), tunnel.

The global pandemic of COVID-19 highlights the importance of vaccination, which remains the most efficient measure against many diseases. Despite the progress in vaccine design, concerns with suboptimal antigen immunogenicity and delivery efficiency prevail. Self-adjuvant carriers–vehicles that can simultaneously deliver antigens and act as adjuvants–may improve efficacies in these aspects. Here, we developed a self-adjuvant carrier based on an acetyl glucomannan (acGM), which can activate toll-like receptor 2 (TLR2) and encapsulate the model antigen ovalbumin (OVA) via a double-emulsion process. In vitro tests showed that these OVA@acGM-8k nanoparticles (NPs) enhanced cellular uptake and activated TLR2 on the surface of dendritic cells (DCs), with increased expression of co-stimulatory molecules (e.g. CD80 and CD86) and pro-inflammatory cytokines (e.g. TNF-α and IL12p70). In vivo experiments in mice demonstrated that OVA@acGM-8k NPs accumulated in the lymph nodes and promoted DCs’ maturation. The immunization also boosted the humoral and cellular immune responses. Our findings suggest that this self-adjuvant polysaccharide carrier could be a promising approach for vaccine development.

This study studies the multiple‐input–multiple‐output (MIMO) performance in a tunnel scenario for the millimetre‐wave (mm‐wave) band. We simulated and measured channel impulse response at 28 GHz for grids of transmitters and receivers to study the feasibility of mm‐wave MIMO system for metro communication in tunnel environment. The ray‐tracing method was utilised to obtain the MIMO channel matrices. The performance of the channel is studied in terms of 2 × 2 and 4 × 4 MIMO, and the influences of antenna spacing on the channel capacity are investigated. The results provide a reference for the fifth‐generation wireless network in the future communication‐based train control system applications.