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Injectable scaffolds are appealing for tissue regeneration because they offer many advantages over pre-formed scaffolds. This article provides a comprehensive review of the injectable ...scaffolds currently being investigated for dental and craniofacial tissue regeneration. First, we provide an overview of injectable scaffolding materials, including natural, synthetic, and composite biomaterials. Next, we discuss a variety of characteristic parameters and gelation mechanisms of the injectable scaffolds. The advanced injectable scaffolding systems developed in recent years are then illustrated. Furthermore, we summarize the applications of the injectable scaffolds for the regeneration of dental and craniofacial tissues that include pulp, dentin, periodontal ligament, temporomandibular joint, and alveolar bone. Finally, our perspectives on the injectable scaffolds for dental and craniofacial tissue regeneration are offered as signposts for the future advancement of this field.
Meteorites exposed to high pressures and temperatures during impact-induced shock often contain minerals whose occurrence and stability normally confine them to the deeper portions of Earth's mantle. ...One exception has been MgSiO3 in the perovskite structure, which is the most abundant solid phase in Earth. Here we report the discovery of this important phase as a mineral in the Tenham L6 chondrite and approved by the International Mineralogical Association (specimen IMA 2014-017). MgSiO3-perovskite is now called bridgmanite. The associated phase assemblage constrains peak shock conditions to ∼ 24 gigapascals and 2300 kelvin. The discovery concludes a half century of efforts to find, identify, and characterize a natural specimen of this important mineral.
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•The data-driven compensation method of the 5-axis machine tools is proposed.•The relationship between the thermal error and positioning error is explored. A novel thermal error is ...proposed for feed drive systems.•The regression analysis is effective to establish the thermal error model.•The pre-stretch can improve the positioning accuracy.
The data-driven thermal error compensation method of high-speed and precision five-axis machine tools was proposed based on the homogeneous transformation. The compensation component was obtained by analyzing the error transmission chain of machine tools and was expressed as the transmission matrix consisting of thermal error terms of linear axes and spindle system according to the differential movement of the compensation axis. From the view of thermal error generation mechanism, the thermal error of the linear axis was formulated as the product of the polynomial function with time as its independent variable and the polynomial function with position as its independent variable. Then the thermal errors of the linear axes were decomposed and identified from the measured positioning error. The thermal error of the spindle system was identified by the thermal characteristic experiments. The compensation component in each direction is calculated by substituting the identified thermal error terms of the linear axes and spindle system into the data-driven thermal error model. Finally, to demonstrate the effectiveness of the proposed method, the thermal error at a new working condition was predicted, and then the error compensation and actual machining were carried out. The results show that the machining error is reduced by more than 85% and 37% with the present error compensation compared with that without compensation and that without traditional error compensation, respectively. This research sheds new light on both the generation mechanism and the compensation method of the thermally-induced error of five-axis machine tools.
Flexible MWCNTs can construct MGPs to form 3-D hybrid structure which inhibit face to face aggregation of multi-graphene platelets and MWCNTs can act as extended coordinating arms for the 3-D hybrid ...architectures, these arms entangle with polymer chain to provide stronger interaction between MWCNTs/MGPs and the epoxy matrix. A remarkable synergetic effect between the MGPs and MWCNTs on the enhanced mechanical properties and thermal conductivity of these epoxy composites was demonstrated.
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► Tortuous MWCNTs construct MGPs to form 3-D hybrid structure and inhibit aggregation. ► MWCNTs act as extended coordinating arms for the hybrid architectures in composites. ► 3-D hybrid architectures exhibit a synergetic effect on performance of composites.
A remarkable synergetic effect between the multi-graphene platelets (MGPs) and multi-walled carbon nanotubes (MWCNTs) in improving the mechanical properties and thermal conductivity of epoxy composites is demonstrated. Stacking of individual two-dimensional MGPs is effectively inhibited by introducing one-dimensional MWCNTs. Long and tortuous MWCNTs can bridge adjacent MGPs and inhibit their aggregation, resulting in a high contact area between the MGP/MWCNT structures and the polymer matrix. Scanning electron microscope images of the fracture surfaces of the epoxy matrix showed that MWCNT/MGP hybrid nanofillers exhibited higher solubility and better compatibility than individual MWCNTs and MGPs did. The tensile strength of GD400-MWCNT/MGP/epoxy composites was 35.4% higher than that of the epoxy alone, compared to only a 0.9% increase in tensile strength for MGP/epoxy composites over the epoxy compound. Thermal conductivity increased by 146.9% using GD400-MWCNT/MGP hybrid fillers and 23.9% for MGP fillers, compared to non-derivatised epoxy.
New approaches are proposed for nonlinear process monitoring and fault diagnosis based on kernel principal component analysis (KPCA) and kernel partial least analysis (KPLS) models at different ...scales, which are called multiscale KPCA (MSKPCA) and multiscale KPLS (MSKPLS). KPCA and KPLS are applied to these multiscale data to capture process variable correlations occurring at different scales. Main contribution of the paper is to propose nonlinear fault diagnosis methods based on multiscale contribution plots. In particular, the nonlinear scores of the variables at each scale are derived. These nonlinear scale contributions can be computed, which is very useful in diagnosing faults that occur mainly at a single scale. The proposed methods are applied to process monitoring of a continuous annealing process and fused magnesium furnace. Application results indicate that the proposed approach effectively captures the complex relations in the process and improves the diagnosis ability.
We prepared flexible, lightweight, and high electromagnetic interference (EMI) shielding performance graphene nanosheet (GNS)/water-borne polyurethane (WPU) composites. WPU, with sulfonate functional ...groups, was used as the polymer matrix. By adsorbing the cationic surfactant (stearyl trimethyl ammonium chloride) on the surface of the GNSs (S-GNSs), restacking and aggregation of the GNSs have been efficiently suppressed, which also attracted sulfonate groups from the WPU matrix. Because of the favorable interfacial interactions arising from electrostatic attraction, the S-GNS exhibited good compatibility with the WPU matrix. Such a homogeneous dispersion contributed to the construction of an electrical conductive network. The S-GNS/WPU composite exhibited a low electrical conductivity percolation threshold and an outstanding enhanced electrical conductivity of approximately 5.1S/m. A high EMI shielding effectiveness of approximately 32dB was obtained by the WPU composites with contents of 5vol.% (approximately 7.7 wt.%) S-GNSs.
Despite the recognition that the gut microbiota acts a clinically significant role in cancer chemotherapy, both mechanistic understanding and translational research are still limited. Maximizing drug ...efficacy requires an in‐depth understanding of how the microbiota contributes to therapeutic responses, while microbiota modulation is hindered by the complexity of the human body. To address this issue, a 3D experimental model named engineered microbiota (EM) is reported for bridging microbiota‐drug interaction research and therapeutic decision‐making. EM can be manipulated in vitro and faithfully recapitulate the human gut microbiota at the genus/species level while allowing co‐culture with cells, organoids, and isolated tissues for testing drug responses. Examination of various clinical and experimental drugs by EM reveales that the gut microbiota affects drug efficacy through three pathways: immunological effects, bioaccumulation, and drug metabolism. Guided by discovered mechanisms, custom‐tailored strategies are adopted to maximize the therapeutic efficacy of drugs on orthotopic tumor models with patient‐derived gut microbiota. These strategies include immune synergy, nanoparticle encapsulation, and host–guest complex formation, respectively. Given the important role of the gut microbiota in influencing drug efficacy, EM will likely become an indispensable tool to guide drug translation and clinical decision‐making.
A gradient hydrogel‐based microbial community is presented to simulate the real intestinal microbiome for bridging microbiome‐drug interaction research and treatment decision. This model reveals three mechanisms of drug‐microbiota interaction: immunological effect, bio‐accumulation, and drug metabolism, which provide innovative regulatory approaches for improving the anti‐cancer effect of drugs.
The neglection of thermal-structure interaction of high-speed spindle system may lead to the modeling error of the thermal characteristics. To improve the modeling accuracy, the thermal-structure ...interaction mechanism was analyzed and the closed-loop iterative modeling method of thermal characteristics was proposed to modify the heat sources and thermal boundary conditions of the spindle system in each substep. The heat generation of bearings and built-in motor, the convective coefficients and the thermal contact resistances (TCRs) of bearing joints were computed. The heat generation of bearings was calculated by the SKF bearing thermal model and the results were compared with that obtained by integral method. The heat generation of bearings was modified by considering the combined effect of the lubricant viscosity variation and thermally-induced preload of bearings. Moreover, a novel geometrical-mechanical-thermal model for TCRs was proposed by characterizing the rough surface morphology and by establishing the multi-scale contact mechanics of joint surfaces. To validate the effectiveness of the proposed method, the thermal characteristic experiments of the spindle system were conducted under different rotational speeds. The results showed that the modeling errors in the temperature field and thermal deformation are reduced significantly and that this model has the ability of thermal error compensation.
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•A closed-loop modeling method is proposed to analyze thermal-structure interaction characteristicof spindle system.•Interaction between temperature and thermal deformation is realized by updating heat source and boundary condition.•A novel geometrical-mechanical-thermal predictive model for thermal contact resistance is proposed.•SKF model is much accurate than the integral method based on the quasi-static mechanics analysis of bearings.•Modeling accuracy could be improved by taking TCR and the thermal-structure interaction into consideration.
Non-covalent functionalization was used to functionalize graphene nanosheets (GNSs) through π–π stacking of pyrene molecules with a functional segmented polymer chain, which results in a remarkable ...improvement in the thermal conductivity of GNS-filled polymer composites. The functional segmented poly(glycidyl methacrylate) containing localized pyrene groups (Py-PGMA) was prepared by atom transfer radical polymerization, and Py-PGMA was characterized by nuclear magnetic resonance spectroscopy. Raman spectra, X-ray photoelectron spectroscopy and thermogravimetric analysis reveal the characteristics of Py-PGMA–GNS. Differential scanning calorimetry indicated that the functional groups on Py-PGMA–GNSs can generate covalent bonds with the epoxy matrix, and further form a cross-linked structure in Py-PGMA–GNS/epoxy composites. The Py-PGMA on the GNS surface not only plays an important role to facilitate a homogeneous dispersion in the polymer matrix but also improves the GNS–polymer interaction, which results in a high contact area. Consequently, the thermal conductivity of integrated Py-PGMA–GNS/epoxy composites exhibited a remarkable improvement and is much higher than epoxy reinforced by multi-walled carbon nanotubes or GNSs. The thermal conductivity of 4
phr Py-PGMA–GNS/epoxy has about 20% (higher than that of pristine GNS/epoxy) and 267% (higher than pristine MWCNT/epoxy).
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