A Facile and General Approach to Recoverable High-Strain Multishape Shape Memory Polymers.

Fabricating a single polymer network with no need to design complex structures to achieve an ideal combination of tunable high-strain multiple-shape memory effects and highly recoverable shape memory property is a great challenge for the real applications of advanced shape memory devices. Here, a facile and general approach to recoverable high-strain multishape shape memory polymers is presented via a random copolymerization of acrylate monomers and a chain-extended multiblock copolymer crosslinker. As-prepared shape memory networks show a large width at the half-peak height of the glass transition, far wider than current classical multishape shape memory polymers. A combination of tunable high-strain multishape memory effect and as high as 1000% recoverable strain in a single chemical-crosslinking network can be obtained. To the best of our knowledge, this is the first thermosetting material with a combination of highly recoverable strain and tunable high-strain multiple-shape memory effects.

Sema3A secreted by sensory nerve induces bone formation under mechanical loads.

Bone formation and deposition are initiated by sensory nerve infiltration in adaptive bone remodeling. Here, we focused on the role of Semaphorin 3A (Sema3A), expressed by sensory nerves, in mechanical loads-induced bone formation and nerve withdrawal using orthodontic tooth movement (OTM) model. Firstly, bone formation was activated after the 3rd day of OTM, coinciding with a decrease in sensory nerves and an increase in pain threshold. Sema3A, rather than nerve growth factor (NGF), highly expressed in both trigeminal ganglion and the axons of periodontal ligament following the 3rd day of OTM. Moreover, in vitro mechanical loads upregulated Sema3A in neurons instead of in human periodontal ligament cells (hPDLCs) within 24 hours. Furthermore, exogenous Sema3A restored the suppressed alveolar bone formation and the osteogenic differentiation of hPDLCs induced by mechanical overload. Mechanistically, Sema3A prevented overstretching of F-actin induced by mechanical overload through ROCK2 pathway, maintaining mitochondrial dynamics as mitochondrial fusion. Therefore, Sema3A exhibits dual therapeutic effects in mechanical loads-induced bone formation, both as a pain-sensitive analgesic and a positive regulator for bone formation.

Diagnostic validity of different gonial angle segmentation for the assessment of mandibular growth direction: A retrospective study.

BACKGROUND: The development of the mandible largely determines the sagittal and vertical lateral appearance. The gonial angle (Articulare-Gonion-Menton, Ar-Go'-Me), as a composite indicator, represents the growth direction of the mandible. We proposed a method based on the Frankfort horizontal (FH) plane and its vertical plane (VFH) to divide the gonial angle into sagittal and vertical components (Articulare-Gonion-VFH / Menton-Gonion-FH, Ar-Go'-VFH / Me-Go'-FH) and to compare the accuracy of diagnosing the development of the mandible and maxillofacial structures with other methods. METHODS: Lateral cephalometric films from 736 volunteers aged 6-30 years were collected and analyzed for cephalometric measurements. Four groups of segmentation-based angle, including the FH-based segmentation (Ar-Go'-VFH / Me-Go'-FH), the SN-based segmentation (Articulare-Gonion- Sellion-Nasion plane' vertical plane/ Menton-Gonion- Sellion-Nasion plane, Ar-Go'-VSN / Me-Go'-SN), the Go'-S based segmentation(Articulare-Gonion-Sellion / Menton-Gonion-Sellion, Ar-Go'-S / Me-Go'-S), and the Go'-N based segmentation (Articulare-Gonion-Nasion / Menton-Gonion-Nasion, Ar-Go'-N / Me-Go'-N), as well as commonly used sagittal and vertical indices were measured. Pearson correlation analysis was used to show the representativeness of different segmentation methods on the mandibular growth direction. RESULTS: As the gonial angle decreased with age, all the segmentation-based metrics decreased. The plane-based segmentation metrics, including Ar-Go'-VFH / Me-Go'-FH, Ar-Go'-VSN / Me-Go'-SN, were superior to the point-based segmentation metrics (Ar-Go'-S / Me-Go'-S, and Ar-Go'-N / Me-Go '-N) in evaluating vertical and sagittal development of the mandible. The sagittal indicators displayed alteration of ramus and condyle, while these vertical indicators responded to the alteration of the mandibular corpus and gonial angle. CONCLUSIONS: The gonial angle should be clinically segmented with planes (including SN plane and FH plane) rather than points (including Go'-S and Go'-N) to assess mandibular development. The FH plane-based segmentation method facilitated chair-side diagnosis of the mandibular growth direction.

Antidote or Trojan horse for submerged macrophytes: Role of microplastics in copper toxicity in aquatic environments.

Due to their unique surface structures and physicochemical properties, microplastics (MPs) can adsorb other contaminants, thus impacting their toxicity and fate in aquatic ecosystems. In the present study, the adsorption and transportation of copper ions (Cu2+) in polyethylene (PE, 5 and 150 µm) and their combined effects on four submerged macrophyte species were assessed. Results demonstrated that the addition of PE reduced the Cu2+ concentration in copper sulfate (CuSO4) solution and the adsorption of Cu2+ in PE (10 mg/L) increased with CuSO4 concentration (100-600 µmol/L). PE alone exhibited no inhibitory effects on macrophytes, while Cu2+ showed fatal toxicity toward the macrophytes. However, the combination of PE and Cu2+ showed lower inhibitory effects on macrophytes and the toxicity attenuation varied among species. Additionally, PE may act as a carrier (like a Trojan horse) for the environmental transfer of Cu2+, thereby hosting Cu2+ toxicity against macrophytes in the imported environment. Our findings indicate that PE acts as both an antidote to and carrier of Cu2+ toxicity in macrophytes. This study should help in clarifying the combined effects and risk assessments of MPs and heavy metals in future studies.

Fabrication of functional waterborne polyurethane/montmorillonite composites by click chemistry method.

"Click" chemistry method was used to fabricate novel waterborne polyurethane (WPU)/montmorillonite (MMT) composites based on alkyne-containing WPU and azide-modified montmorillonite. The morphology of these composites was characterized by x-ray diffractometer, scanning electron microscope. The mechanical properties, thermal stability, and flame resistance of the composites were investigated by tensile, thermogravimetry and cone calorimetric experiments, etc. The experimental results show that the tensile strength, water resistance and flame retardancy of the WPU/MMT composites have been reinforced efficiently owing to the linking of MMT by click reaction.