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Bone malunion or nonunion leads to functional and esthetic problems and is a major healthcare burden. Activation of bone marrow mesenchymal stem cells (BMSCs) and subsequent induction of osteogenic differentiation by local metabolites are crucial steps for bone healing, which has not yet been completely investigated. Here, we found that lactate levels are rapidly increased at the local injury site during the early phase of bone defect healing, which facilitates the healing process by enhancing BMSCs regenerative capacity. Mechanistically, lactate serves as a ligand for the Olfr1440 olfactory receptor, to trigger an intracellular calcium influx that in turn activates osteogenic phenotype transition of BMSCs. Conversely, ablation of Olfr1440 delays skeletal repair and remodelling, as evidenced by thinner cortical bone and less woven bone formation in vivo. Administration of lactate in the defect area enhanced bone regeneration. These findings thus revealed the key roles of lactate in the osteogenic differentiation of BMSCs, which deepened our understanding of the bone healing process, as well as provided cues for a potential therapeutic option that might greatly improve bone defect treatment. [ABSTRACT FROM AUTHOR]

External cervical resorption (ECR) is a relatively uncommon yet aggressive form of dental hard tissue destruction. It is initiated at the cervical aspect of the root surface and extends apicocoronally and circumferentially inside the dentin. Despite the large number of case reports and clinical studies that have investigated ECR, its etiology remains unclear. Recent advancements in clinical assessment measures, such as the use of cone-beam computed tomographic imaging, have provided additional insights into the nature of this lesion. This has facilitated the continued development and improvement of treatment methods for this condition. In this article, we provide an overview of the latest research pertaining to the etiology, histopathology, predisposing factors, diagnosis, classification, and treatment of ECR. Furthermore, we provide a summary of the different classification schemes for ECR and highlight the relevant therapeutic principles. [ABSTRACT FROM AUTHOR]

Abstract: Fe3O4 magnetic nanoparticles (MNPs) were synthesized by a co-precipitation method using sodium citrate and oleic acid as modifiers. Phase composition and microstructure analysis indicate that the sodium citrate and oleic acid have been successfully grafted onto the surface of Fe3O4 MNPs. The magnetic behaviors reveal that the modification can decrease the saturation magnetization of Fe3O4 MNPs due to the surface effect. Fe3O4 MNPs modified by sodiumcitrate and oleic acid show excellent dispersion capability, which should be ascribed to the great reduction of high surface energy and dipolar attraction of the nanoparticles. [Copyright &y& Elsevier]

Abstract: In this study, poly (L-lactic acid) (PLLA)/trifluoroethanol (TFE) solution was electrospun to fabricate fibrous scaffolds with different fiber orientations. Random and parallel PLLA nanofiber alignments were achieved by using a metal plate and a rolling rod as the receiver, respectively. The parallel PLLA fibrous scaffolds were further hot-stretched to obtain hyperparallel PLLA fibrous scaffolds. The PLLA fibrous scaffolds were characterized by fiber diameter, interfiber distance, fiber array angle, water contact angle, morphology and mechanical strength. The tensile strength of hyperparallel nano-fibers was approximately 5- and 14-times the parallel and random fibers, respectively. Osteoblast-like MG63 cells were cultured on the PLLA scaffolds to study the effects of fiber orientation on cell morphology, proliferation and differentiation. The cells on the randomly-oriented scaffolds showed irregular forms, while the cells exhibited shuttle-like shapes on the parallel scaffolds and had larger aspect ratios along the fiber direction of the hyperparallel scaffolds. Alkaline phosphatase (ALP) activity and collagen I (placeStateCol I) and osteocalcin (OC) deposition exhibited fiber orientation dependence. With an increase in parallelism of the fibers, there was a decrease in ALP activity and placeStateCol I and OC production. These results suggest that exploitation of PLLA fiber orientation may be used to control osteoblast-like cell responses. [Copyright &y& Elsevier]

mRNA m6A modification is heavily involved in modulation of immune responses. However, its function in antiviral immunity is controversial, and how immune responses regulate m6A modification remains elusive. We here find TBK1, a key kinase of antiviral pathways, phosphorylates the core m6A methyltransferase METTL3 at serine 67. The phosphorylated METTL3 interacts with the translational complex, which is required for enhancing protein translation, thus facilitating antiviral responses. TBK1 also promotes METTL3 activation and m6A modification to stabilize IRF3 mRNA. Type I interferon (IFN) induction is severely impaired in METTL3-deficient cells. Mettl3 fl/fl-lyz2-Cre mice are more susceptible to influenza A virus (IAV)-induced lethality than control mice. Consistently, Ythdf1 −/− mice show higher mortality than wild-type mice due to decreased IRF3 expression and subsequently attenuated IFN production. Together, we demonstrate that innate signals activate METTL3 via TBK1, and METTL3-mediated m6A modification secures antiviral immunity by promoting mRNA stability and protein translation. [Display omitted] • TBK1 directly phosphorylates METTL3 at serine 67 upon VSV infection • TBK1 promotes catalytic activity of METTL3 • S67 phosphorylation enhances METTL3 function in promoting translation Chen et al. report that TBK1 promotes METTL3-related translation and m6A modification in a kinase-activity-dependent and -independent manner. This study therefore advances our understanding of how innate signals interplay with METTL3 in host defense against virus. [ABSTRACT FROM AUTHOR]

As a wide and direct bandgap semiconductor material, two-dimensional (2D) graphene-like SiC has attracted extensive research attention recently. Native defects and foreign impurities often have remarkable effects on the properties of semiconductors. In this paper, the structural, mechanical and electrical properties of 2D SiC with carbon antisite (C Si), vacancy (V C), interstitial (C i) and substitution of C by N (N C) and B (B C) have been studied systematically using first-principles calculations. It is found that defects do not cause structural reconstruction for 2D SiC. The formation energies of C Si , V C , N C and B C are not sensitive to the uniaxial strain. C Si and C i are likely to be formed spontaneously due to the negative formation energy values. In addition, the phonon spectra and elastic constant calculations show that the properties of 2D SiC with V C and C i are unstable. Furthermore, from the calculations of the band structures and density of states, we observed that the bandgap of 2D SiC is slightly reduced by C Si , V C , C i , and N C , however is increased by B C. Prominent additional charge states are generated in the bandgap of 2D SiC except for N C. Moreover, the overall carrier mobility of 2D SiC could be significantly reduced by the defects. • The structural, mechanical and electrical properties of 2D SiC with C-related defects are studied. • C-related point defects and substitution of C by foreign atoms do not cause structural reconstruction for 2D SiC. • Carbon vacancy (V C) and interstitial (C i) could break the dynamical and mechanical stability of 2D SiC. • The bandgap of 2D SiC is slightly reduced by C Si , V C and interstitial (C i) with additional charge states. • The overall carrier mobility of 2D SiC could be significantly reduced by the defects. [ABSTRACT FROM AUTHOR]

Abstract: Porous -tricalcium phosphate (TCP)/collagen composites with different -TCP/collagen weight ratio were prepared. The influences of the preparation conditions on the microstructure of porous composite and the joint status of -TCP particles with collagen fibrils were characterized by X-ray diffractometer, scanning electron microscopy and transmission electron microscopy. The results showed: (1) an acid treatment could effectively disassemble collagen fibrils; (2) in the resulting porous composites, -TCP particles homogenously existed on the skeleton of the collagen fibril network and bonded tightly to both the fibrils and themselves. The tight bonding formation could be due to the reaction between Ca ions in the particles and carboxyl groups in collagen polypeptide chains and due to the reprecipitation of partially dissolved -TCP during synthesis. The tight bonding between -TCP particles and collagen fibrils in the composites demonstrated an integrated structure, which was reproducible when -TCP/collagen ratio ranged from 2 to 4. Such integrated structure would make significant contributions in reliably tailoring properties of the porous composites by varying -TCP content. In addition, the porous composites had large porosity (∼95%) and appropriate pore size (∼100μm), showed no negative impact in cytotoxicity assay and complete bone tissue regeneration after 12 weeks in animal test. [Copyright &y& Elsevier]

Abstract Injectable hydrogels are promising candidates for tissue engineering because of their easy and minimally invasive manipulation, and their ability to mimic the features of the extracellular matrix. Hydrogels developed from water-soluble polyphosphazenes are attractive due to the unique flexibility of phosphazene chemistry. In this study, a photocrosslinkable water-soluble polyphosphazene was synthesized by introducing citronellol with a double bond and hydrophilic diethylene glycol monomethyl ether as cosubstituted side groups; the corresponding hydrogel was obtained by exposing the polyphosphazene aqueous solution to ultraviolet light. Benefiting from the elastic polyphosphazene backbone and the flexible ether side group, the hydrogel exhibited excellent injectability and mechanical stability. To improve the hydrogel's mechanical and biological properties targeting biomedical applications, photocrosslinkable methacrylate gelatin and inorganic calcium phosphate were incorporated. The resulting composite hydrogels were able to retain excellent injectability, deformability and fatigue resistance, and were evaluated to be excellent for biomedical applications via in vitro cell culture and in vivo subcutaneous implantation. Graphical abstract Unlabelled Image Highlights • Citronellol-substituted water soluble polyphosphazene was synthesized. • Polyphosphazene/gelatin hybrid hydrogels are obtained via photo-crosslinking. • Inorganic calcium phosphate is incorporated via in situ precipitation method. • The hydrogels display excellent injectability, deformability and fatigue resistance. • The hydrogels are non-cytotoxic and biocompatible for biomedical applications. [ABSTRACT FROM AUTHOR]

Objective The objective of this study was to develop a rapid and effective method to remineralize human carious-like enamel using chimaeric peptide-mediated nanocomplexes of carboxymethyl chitosan/amorphous calcium phosphate (CMC/ACP), mimicking the mineralizing pattern of the oriented assembly of ACP guided by amelogenin in the biomineralization of enamel. Methods CMC/ACP nanocomplex solution was first synthesized through the successive addition of carboxymethyl chitosan, calcium chloride, and dipotassium phosphate into distilled water. ACP nanoparticles were degraded by 1% NaClO from CMC/ACP nanocomplexes. The morphology of the particles at different periods was tested by transmission electron microscopy (TEM). The chimaeric peptides were added to guide the arrangement of ACP nanoparticles and to bind ACP nanoparticles to the demineralized enamel surface specifically. X-ray diffraction (XRD)/scanning electron microscope (SEM)/confocal laser scanning microscopy (CLSM)/nano-indentation tests were applied to check the remineralization effects. Results CMC/ACP nanocomplexes were obtained and could be kept without precipitation for a long time. After the degradation of NaClO and guidance of chimaeric peptides, ACP nanoparticles were arranged into oriented arrays before transforming into crystals, and the enamel-like crystals were tightly bound onto the demineralized surface. The newly formed enamel-like crystals were nearly well-organized and equipped with strong mechanical properties. [ABSTRACT FROM AUTHOR]

Fluid catalytic cracking (FCC) is one of the main processes for gasoline/diesel production in the oil refining industry, it is a challenge to design catalyst towards high gasoline/diesel yield and low coke formation (i.e. lower CO 2 emission). Take this into account, a set of ultra-stable Y (USY) zeolites with varied mesopore structures were designed and prepared for the catalytic cracking of a renewable oil source Jatropha Curcas L. seed oil (JCO). Reaction temperature and catalyst-to-oil (C/O) ratio were also investigated. It was found that, the catalyst with larger mesopore volume showed enhanced gasoline/diesel selectivities, higher olefins and lower aromatics yield in gasoline which gave rise to lower octane number. The catalyst with smaller mesopore volume enhanced hydride transfer activity, and gave the lowest coke yield and the highest octane number. To obtain high gasoline/diesel yield, large USY mesopore volume, low reaction temperature and low C/O ratio is required. With the aim of low coking and high octane gasoline, small USY mesopore volume, moderate reaction temperature (such as 480 °C) and moderate C/O ratio (such as 6, wt/wt) is good choice for gasoline/diesel production via JCO catalytic cracking. As such, the catalyst prepared from mesoporous USY may find application for obtaining liquid hydrocarbon fuels from JCO. [ABSTRACT FROM AUTHOR]

The major objective of this study was to explore the effects of silicon dioxide (SiO 2 ) nanofibers on the performance of 2, 2-bis-[4-(methacryloxypropoxy)-phenyl]-propane (Bis-GMA)/tri-(ethyleneglycol) dimethacrylate (TEGDMA) dental composites. At first, the mechanical properties of Bis-GMA/TEGDMA (50/50, w/w) resins containing different contents of SiO 2 nanofibers were evaluated to identify the appropriate composition to achieve the significant reinforcing effect. Secondly, optimized contents (5 or 10 wt.%) of SiO 2 nanofibers were mixed into resins together with SiO 2 microparticles, which was 60 wt.% of the resin. Controls for comparison were Bis-GMA/TEGDMA resins containing only SiO 2 microparticles (60 wt.%) or with additional SiO 2 nanoparticles (5 or 10 wt.%). Properties including abrasion, polymerization shrinkage and mechanical properties were evaluated to determine the contribution of SiO 2 nanofibers. In comparison with SiO 2 nanoparticles, SiO 2 nanofibers improved the overall performance of Bis-GMA/TEGDMA composite resins, especially in improving abrasion resistance and decreasing polymerization shrinkage. The explanations were that one-dimensional SiO 2 nanofibers were able to shield particular fillers from being abraded off, and able to form a kind of overlapped fibrous network to resist polymerization shrinkage. With these approaches, SiO 2 nanofiber-containing Bis-GMA composite resins were envisioned a promising choice to achieve long-term durable restorations in clinical therapies. [ABSTRACT FROM AUTHOR]

To obtain a kind of light-curable fiber-reinforced composite for dental restoration, an excellent interfacial adhesion between the fiber and the acrylate resin matrix is quite essential. Herein, surface modification on glass fibers were carried out by coating them with poly(methyl methacrylate) (PMMA), polydopamine (PDA), or both. The PMMA or PDA coating was performed by soaking fibers in PMMA/acetone solution or dopamine aqueous solution. PDA/PMMA co-coated glass fibers were obtained by further soaking PDA-coated fibers in PMMA/acetone solution. These modified fibers were impregnated with bisphenol A glycidyl methacrylate (Bis-GMA)/triethylene glycol dimethacrylate (TEGDMA) (5:5, w/w) dental resin at a volume fraction of 75%, using unmodified fibers as reference. Light-cured specimens were submitted to evaluations including flexural properties, morphological observation, dynamic mechanical thermal analysis (DMTA) and pull-out test. In comparison with unmodified glass fibers, all the modified glass fibers showed enhancements in flexural strength and modulus of Bis-GMA/TEGDMA resin composites. Results of DMTA and pull-out tests confirmed that surface modification had significantly improved the interfacial adhesion between the glass fiber and the resin matrix. Particularly, the PDA/PMMA co-coated glass fibers displayed the most efficient reinforcement and the strongest interfacial adhesion due to the synergetic effects of PDA and PMMA. It indicated that co-coating method was a promising approach in modifying the interfacial compatibility between inorganic glass fiber and organic resin matrix. [ABSTRACT FROM AUTHOR]

Proliferation and differentiation of bone-related cells are modulated by many factors such as scaffold design, growth factor, dynamic culture system, and physical simulation. Nanofibrous structure and moderate-intensity (1 mT–1 T) static magnetic field (SMF) have been identified as capable of stimulating proliferation and differentiation of osteoblasts. Herein, magnetic nanofibers were prepared by electrospinning mixture solutions of poly( l -lactide) (PLLA) and ferromagnetic Fe 3 O 4 nanoparticles (NPs). The PLLA/Fe 3 O 4 composite nanofibers demonstrated homogeneous dispersion of Fe 3 O 4 NPs, and their magnetism depended on the contents of Fe 3 O 4 NPs. SMF of 100 mT was applied in the culture of MC3T3-E1 osteoblasts on pure PLLA and PLLA/Fe 3 O 4 composite nanofibers for the purpose of studying the effect of SMF on osteogenic differentiation of osteoblastic cells on magnetic nanofibrous scaffolds. On non-magnetic PLLA nanofibers, the application of external SMF could enhance the proliferation and osteogenic differentiation of MC3T3-E1 cells. In comparison with pure PLLA nanofibers, the incorporation of Fe 3 O 4 NPs could also promote the proliferation and osteogenic differentiation of MC3T3-E1 cells in the absence or presence of external SMF. The marriage of magnetic nanofibers and external SMF was found most effective in accelerating every aspect of biological behaviors of MC3T3-E1 osteoblasts. The findings demonstrated that the magnetic feature of substrate and microenvironment were applicable ways in regulating osteogenesis in bone tissue engineering. [ABSTRACT FROM AUTHOR]

In this study, a strategy of using iodine-containing cyclophosphazenes as radiopacifiers for dental composite resin was evaluated. It was hypothesized that cyclophosphazenes bearing both iodine and acrylate group swere able to endow composite resins radiopacity without compromising mechanical properties. The cyclophosphazene compounds were synthesized by subsequently nucleophilic substitution of hexachlorocyclotriphosphazene with hydroxyethyl methacrylate (HEMA) and 4-iodoaniline. Cyclotriphosphazenes containing two different molar ratios of HEMA to 4-iodoaniline (1:5 and 2:4) were obtained, and were identified with 1 H NMR, FT-IR, UV and mass spectroscopy. The iodine-containing cyclophosphazenes were able to dissolve well in bisphenol A glycidyl methacrylate (Bis-GMA)/triethylene glycol dimethacrylate (TEGDMA) resin, and were added at two contents (10 or 15%wt. of the resin). The resins were photo-cured and post-thermal treated before characterizations. The resulting composite resins demonstrated the ability of blocking X-ray. And the addition of HEMA-co-iodoaniline substituted cyclotriphosphazenes caused minor adverse effect on the mechanical properties of the resins because the cyclotriphosphazenes could mix well and react with the resins. The presence of rigid phosphazene rings between resin backbones displayed an effective function of decreasing polymerization shrinkage. In summary, soluble and reactive iodine-containing cyclotriphosphazenes demonstrated advantages over traditional heavy metals or metal oxides in being used as additives for producing radiopaque dental resins. [ABSTRACT FROM AUTHOR]

Abstract: A kind of core–shell nanofibers containing sodium fluoride (NaF) was produced and used as reinforcing materials for dimethacrylate-based dental restorative resins in this study. The core–shell nanofibers were prepared by coaxial-electrospinning with polyacrylonitrile (PAN) and poly(methyl methacrylate) (PMMA) solutions as core and shell fluids, respectively. The produced PAN–PMMA nanofibers varied in fiber diameter and the thickness of PMMA shell depending on electrospinning parameters. NaF-loaded nanofibers were obtained by incorporating NaF nanocrystals into the core fluid at two loadings (0.8 or 1.0wt.%). Embedment of NaF nanocrystals into the PAN core did not damage the core–shell structure. The addition of PAN–PMMA nanofibers into Bis-GMA/TEGDMA clearly showed the reinforcement due to the good interfacial adhesion between fibers and resin. The flexural strength (Fs) and flexural modulus (Ey) of the composites decreased slightly as the thickness of PMMA shell increasing. Sustained fluoride releases with minor initial burst release were achieved from NaF-loaded core–shell nanofibers and the corresponding composites, which was quite different from the case of embedding NaF nanocrystals into the dental resin directly. The study demonstrated that NaF-loaded PAN–PMMA core–shell nanofibers were not only able to improve the mechanical properties of restorative resin, but also able to provide sustained fluoride release to help in preventing secondary caries. [Copyright &y& Elsevier]

Abstract: Combinations of calcium phosphate scaffolds and bioactive factors are promising niche-mimetic solutions for repairing large-sized bone defects. However, the importance of compatibility between scaffolds and bioactive factors on their osteogenic outcomes has been largely ignored. This study aimed to investigate the compatibility of calcinated antler cancellous bone (CACB) scaffolds with various bioactive factors including icariin (ICA), velvet antler polypeptides (VAP) or recombinant human bone morphogenetic protein-2 (rhBMP-2) as well as their combinational osteogenic potential in vitro and in vivo. Scanning electron microscopy and fourier transform infrared spectroscopy confirmed the uniform distribution and chemical stability of the reagents on CABC. In vitro release profiles showed relative steady release of ICA from ICA/CACB, burst VAP release from VAP/CACB, and minimal rhBMP-2 release from rhBMP-2/CACB composites. When compared with VAP and rhBMP-2, incorporation of ICA within CACB resulted in most increased cell attachment, proliferation, alkaline phosphatase activity, osteogenic gene expression, and mineralization of rat bone marrow mesenchymal stem cells. In rabbit mandible critical-sized defects, the most extensive osteogenesis and neovascularization were observed in the ICA/CACB group. Differences between the VAP/CACB and rhBMP-2/CACB groups were not apparent. Interestingly, low pro-inflammatory (TNF-α, IL-6) and high anti-inflammatory (IL-10) mRNA levels were observed at scaffold implantation sites which were in close association with amount of new bone formation. These findings highlight that the compatibility between scaffolds and bioactive factors should been taken into account when considering the formula of optimized bone defect repair. [Copyright &y& Elsevier]

Abstract: In this paper, we present the release of baicalin from hexagonal periodic mesoporous silica SBA-15 and amino-functionalized mesoporous SBA-15 (A-SBA-15), which serve as drug delivery systems (SBA-15/baicalin and A-SBA-15/baicalin). The modified and drug loaded mesoporous materials were characterized by XRD, SEM, TEM, N2 physisorption, IR, TG and HPLC. The results demonstrated that slightly higher amount of baicalin was loaded in APS-SBA-15, and the dissolution rate of baicalin from the A-SBA-15/baicalin was much faster than from the SBA-15/baicalin. A-SBA-15/baicalin as baicalin delivery system was better than SBA-15/baicalin because the faster dissolution rate compared with SBA-15/baicalin was more conducive to drug absorption. [Copyright &y& Elsevier]

Abstract: Poly(lactide-co-glycolide) (PLGA) copolymers are the most prevalent materials for tissue engineering applications. To mimic the real microenvironment of extracellular matrix (ECM) for cell growth, nanofibrous PLGA scaffolds are preferred. PLGA5050 (in which the molar ratio of lactidyl to glycolidyl units is 50:50), which is an utterly amorphous polymer, was first reported to be made into nanofibrous networks (fiber diameter around 500nm) using phase separation from PLGA5050/THF solutions in this study. The concentration of polymeric solution had significant effects on fiber diameter and unit length. Nonsolvent (e.g. H2O) was unnecessary to form the PLGA5050 gel, which was critical to nanofibrosis, as if the environmental temperature for gelation occurrence was low enough (−70°C). The physical crosslinks to stabilize the PLGA5050/THF gel were believed to be GA segments along the backbone owing to their inferior solubility in THF. The addition of H2O would cause adverse effects of liquid–liquid phase separation and nanofibrosis failure owing to the hydrophilicity of glycolidyl units. Associating with the phase separation method, particle-leaching technique was applied to fabricate three-dimensional scaffolds with macroporous and nanofibrous structures. To ensure the occurrence of nanofibrosis on macropore walls, the temperature of salt particles should be best lowed to −70°C beforehand. Accordingly, scaffolds prepared under varied parameters exhibited different nanofiber and pore morphologies, which affected the pore size, porosity, specific surface area, water contact angle and protein adsorption ability etc. The preliminary cell (MC3T3-E1) culture confirmed the cell ingrowth into the macroporous and nanofibrous PLGA5050 scaffolds in comparison with the solely nanofibrous matrixes. This kind of bi-scaled three dimensional matrixes can be superior candidate scaffolds for tissue engineering applications. [Copyright &y& Elsevier]

Abstract: Objectives: The polyacrylonitrile (PAN)–poly(methyl methacrylate) (PMMA) core–shell nanofiber reinforced dental composites have been investigated for their excellent interface adhesive, and this kind of novel dental composite has the potential for clinical uses such as denture base resin and crown–bridge material. The first objective of this work was to determine the improving effect of tensile properties by post-drawing PAN–PMMA nanofibers membrane. The second objective was to examine the flexural strength (Fs), flexural modulus (Ey) and work of fracture (WOF) of Bis-GMA/TEGDMA composites reinforced with PAN–PMMA nanofibers. Methods: PAN(core)–PMMA(shell) nanofiber was made by an electrospinning setup with a high-speed rotating rod-like collector. The post-draw process was carried out at 120°C for 5min, and all the nanofiber membranes were elongated to the desired elongation ratio (30%, 60% or 100%). Tensile properties and flexural properties of both nanofiber membranes and nanofiber reinforced Bis-GMA/TEGDMA composites were investigated. A scanning electron microscope (SEM) was used to observe the fiber morphology and the fracture surface of the composite. A dynamic mechanical thermal analyzer (DMTA) was employed to determine the dynamic mechanical properties such as tan δ and E′. Results: The post-drawing treatment significantly improved the tensile properties and fiber parallelism of nanofiber membranes. The addition of PAN–PMMA nanofibers into Bis-GMA/TEGDMA clearly showed the reinforcement effect; the flexural strength (Fs), flexural modulus (Ey) and work of fracture (WOF) kept rising with the nanofiber mass fraction changing from 0%, 0.6%, 0.8%, 1.0% to 1.2%. The flexural properties of composites reinforced with post-drawn nanofiber were further increased in comparison with those of untreated nanofiber reinforced ones. Also, the SEM observations of the fracture surface of the composites demonstrated good interfacial adhesion between fibers and resin. Significance: The post-drawing treatment was confirmed as a useful method for significantly increasing the tensile strength (673.4%) and tensile modulus (875.3%) of nanofiber membranes. In addition, the composites reinforced with post-drawn PAN–PMMA nanofibers exhibited higher Fs (13.6%), Ey (5.3%) and WOF (30.4%) than those reinforced with as-electrospun PAN–PMMA nanofibers. When 1.2% mass fraction of post-drawn nanofibers were added to Bis-GMA/TEGDMA resin, the Fs, Ey and WOF increased by 51.6%, 64.3% and 152.0%, respectively, compared with neat resin. [Copyright &y& Elsevier]

Abstract: Carbon nanofibers decorated with β-tricalcium phosphate (β-TCP) nanoparticles (β-TCP/CNFs) have been prepared by sintering electrospun polyacrylonitrile fibers with calcium nitrate tetrahydrate as the calcium source and triethyl phosphate as the phosphorus source. Microstructure and phase composition analysis indicate that the resulting materials are composed of β-TCP nanoparticles and CNFs. And the long β-TCP/CNFs can be cut into organism-eliminable short CNFs gradually in hydrochloric acid solution due to the solubilization of β-TCP nanoparticles. The materials exhibit good biocompatibility, and have comparable effect on cell growth with pure CNFs, with their tuning ability in degradation. [Copyright &y& Elsevier]

Abstract: PAN core–PMMA shell nanofiber fabric was prepared by electrospinning of polymer blends to reinforce 2,2-bis-[4-(methacryloxypropoxy)-phenyl]-propane (Bis-GMA) a dental resin system. The core–shell structure of the PAN–PMMA nanofiber was confirmed by scanning electron microscopy (SEM) and transmission electron microscope/energy dispersive spectroscopy (TEM/EDS) observation. The flexural properties and dynamic mechanical properties of the PAN–PMMA nanofiber reinforced Bis-GMA composites were studied. Results showed that PMMA shell was partly dissolved with the Bis-GMA resin. After photopolymerization, liner PMMA chains interpenetrated and entangled with the dental resin network, which resulted in an in situ nano-interface in the shell structure. Improvement of the mechanical properties of the PAN–PMMA nanofiber reinforced Bis-GMA composites has been achieved through this nano-interface formation. [Copyright &y& Elsevier]

To sequentially track mandibular defect repair by using radiographic and histological techniques, so as to compare repair patterns of sensory denervated versus innervated mandibles. Forty Sprague-Dawley rats were subjected to unilateral inferior alveolar nerve (IAN) axotomy and bilateral 3 mm full-thickness circular osteotomy of their mandibles. Micro-CT and histological staining were applied to track the repair process of the mandibular defects at 1, 2, 4, and 8 weeks after surgery. The bone volume of both sides increased by 2 weeks post-operation, and then gradually decreased. The new bone volumes of the axotomy side were significantly less than that of the sham side at 1, 2, and 4 weeks post-surgery, whereas no significant differences were detected at 8 weeks post-surgery. Meanwhile, there were no significant differences in bone mineral density between the two sides during repair. Noteworthy, the repaired bone remained more vertically than horizontally aligned throughout the repair process. IAN axotomy decreases the quantity of bone calluses during the early stage of mandibular defect repair, but with no effect on the degree of mineralization. The shape of the defect area appeared to be aligned with the direction of local mechanical force produced by masticatory muscles. • Sensory denervation decreased the quantity of new bone in mandibular defect repair. • Visualization of mandibular defect repair was first achieved by Echarts. • Force from masticatory muscles affected direction of mandibular defect repair. • The critical size of full-thickness circular mandibular defect seemed ≤ 3 mm. [ABSTRACT FROM AUTHOR]