Entropy Stable DGSEM Schemes of Gauss Points Based on Subcell Limiting.

The discontinuous Galerkin spectral element method (DGSEM) is a compact and high-order method applicable to complex meshes. However, the aliasing errors in simulating under-resolved vortex flows and non-physical oscillations in simulating shock waves may lead to instability of the DGSEM. In this paper, an entropy-stable DGSEM (ESDGSEM) based on subcell limiting is proposed to improve the non-linear stability of the method. First, we discuss the stability and resolution of the entropy-stable DGSEM based on different solution points. Second, a provably entropy-stable DGSEM based on subcell limiting is established on Legendre-Gauss (LG) solution points. Numerical experiments demonstrate that the ESDGSEM-LG scheme is superior in non-linear stability and resolution, and ESDGSEM-LG with subcell limiting is robust in shock-capturing.

Energy Stability Property of the CPR Method Based on Subcell Second-Order CNNW Limiting in Solving Conservation Laws.

This paper studies the energy stability property of the correction procedure via reconstruction (CPR) method with staggered flux points based on second-order subcell limiting. The CPR method with staggered flux points uses the Gauss point as the solution point, dividing flux points based on Gauss weights, with the flux points being one more point than the solution points. For subcell limiting, a shock indicator is used to detect troubled cells where discontinuities may exist. Troubled cells are calculated by the second-order subcell compact nonuniform nonlinear weighted (CNNW2) scheme, which has the same solution points as the CPR method. The smooth cells are calculated by the CPR method. The linear energy stability of the linear CNNW2 scheme is proven theoretically. Through various numerical experiments, we demonstrate that the CNNW2 scheme and CPR method based on subcell linear CNNW2 limiting are energy-stable and that the CPR method based on subcell nonlinear CNNW2 limiting is nonlinearly stable.

Efficacy of Plant Growth-Promoting Bacteria Bacillus cereus YN917 for Biocontrol of Rice Blast.

Bacillus cereus YN917, obtained from a rice leaf with remarkable antifungal activity against Magnaporthe oryzae, was reported in our previous study. The present study deciphered the possible biocontrol properties. YN917 strain exhibits multiple plant growth-promoting and disease prevention traits, including production of indole-3-acetic acid (IAA), ACC deaminase, siderophores, protease, amylase, cellulase, and ß-1,3-glucanase, and harboring mineral phosphate decomposition activity. The effects of the strain YN917 on growth promotion and disease prevention were further evaluated under detached leaf and greenhouse conditions. The results revealed that B. cereus YN917 can promote seed germination and seedling plant growth. The growth status of rice plants was measured from the aspects of rice plumule, radicle lengths, plant height, stem width, root lengths, fresh weights, dry weights, and root activity when YN917 was used as inoculants. YN917 significantly reduced rice blast severity under detached leaf and greenhouse conditions. Genome analysis revealed the presence of gene clusters for biosynthesis of plant promotion and antifungal compounds, such as IAA, tryptophan, siderophores, and phenazine. In summary, YN917 can not only be used as biocontrol agents to minimize the use of chemical substances in rice blast control, but also can be developed as bio-fertilizers to promote the rice plant growth.

Photo-crosslinkable amniotic membrane hydrogel for skin defect healing.

The human amniotic membrane (HAM) collagen matrix derived from human placenta can be decellularized (dHAM) to form a natural biocompatible material. dHAM has different bioactive substances and has been used widely in human tissue engineering research. However, dHAM has some disadvantages, e.g., poor mechanical properties, easy degradation and inconvenient operation and use, so it is not conducive to large-area or full-thickness skin defect healing. To overcome these limitations, for the first time, dHAM was grafted with methacrylic anhydride (MA) to form photocrosslinked dHAM methacrylate (dHAMMA); dHAMMA was then blended with methacrylated gelatin (GelMA), followed by the addition of a photosensitizer for photocrosslinking to obtain the fast-forming GelMA-dHAMMA composite hydrogel. Further, GelMA-dHAMMA was found to have the porous structure of a bicomponent polymer network and good physical and chemical properties. In vitro experiments, GelMA-dHAMMA was found to promote fibroblast proliferation and α-smooth muscle actin (α-SMA) expression. In vivo investigations also demonstrated that GelMA-dHAMMA promotes wound collagen deposition and angiogenesis, and accelerates tissue healing. GelMA-dHAMMA inherits the good mechanical properties of GelMA and maintains the biological activity of the amniotic membrane, promoting the reconstruction and regeneration of skin wounds. Thus, GelMA-dHAMMA can serve as a promising biomaterial in skin tissue engineering. STATEMENT OF SIGNIFICANCE: Since the early 20th century, the human amniotic membrane (HAM) has been successfully used for trauma treatment and reconstruction purposes. dHAM has different bioactive substances and has been used widely in human tissue-engineering research. In this work, the dHAM and gelatin were grafted and modified by using methacrylic anhydride (MA) to form photocrosslinked dHAMMA and methacrylated gelatin (GelMA). Then, the dHAMMA and GelMA were blended with a photosensitizer to form the GelMA-dHAMMA composite hydrogel derived from gelatin-dHAM. GelMA-dHAMMA exhibits a bicomponent-network (BCN) interpenetrating structure. dHAM dydrogel has advantages, e.g., good mechanical properties, slow degradation and convenient operation, so it is conducive to large-area or full-thickness skin defect healing.

Advanced biomaterials for repairing and reconstruction of mandibular defects.

Mandibles are the largest and strongest bone in the human face and are often severely compromised by mandibular defects, compromising the quality of life of patients. Mandibular defects may result from trauma, inflammatory disease and benign or malignant tumours. The reconstruction of mandibular defect has been a research hotspot in oral and maxillofacial surgery. Although the principles and techniques of mandibular reconstruction have made great progress in recent years, the development of biomedical materials is still facing technical bottleneck, and new materials directly affect technological breakthroughs in this field. This paper reviews the current status of research and application of various biomaterials in mandibular defects and systematically elaborates different allogeneic biomaterial-based approaches. It is expected that various biomaterials, in combination with new technologies such as digital navigation and 3D printing, could be tuned to build new types of scaffold with more precise structure and components, addressing needs of surgery and post-reconstruction. With the illustration and systematization of different solutions, aims to inspire the development of reconstruction biomaterials.

Development of a visible light, cross-linked GelMA hydrogel containing decellularized human amniotic particles as a soft tissue replacement for oral mucosa repair.

Early effective treatment of oral mucosal defects is the key to ensuring defect healing and functional recovery. The application of human amniotic membrane (HAM) in promoting wound healing has been shown to be safe and effective. However, amniotic membrane is thin, easy to tear and difficult to handle. Combined with the natural forces at play in the oral cavity, this has restricted the clinical applications of HAM for healing of mucosal defects. Methacrylated gelatin (GelMA) has good mechanical strength and adhesion, and can be used as a bionic repair film to attach to the damaged surface of oral mucosa, but GelMA lacks bioactive substances and cannot promote the rapid repair of oral mucosal defects. The aim of this study was to design a type of composite GelMA hydrogel mixed with decellularized human amniotic particles (dHAP) as an oral mucosa substitute, to promote regeneration of defective mucosa by stimulating rapid angiogenesis. The composite substitute GelMA-dHAP was easy to synthesize and store, and easy to operate for repair of oral mucosal defects. We show the angiogenic potential of GelMA-dHAP on chick chorioallontoic membrane and the curative effect of GelMA-dHAP as a treatment in the rabbit oral mucosa defect model. In conclusion, this study confirms the effectiveness of GelMA-dHAP as an ideal soft tissue substitute for the repair of oral mucosal defects, overcoming the shortcomings of using HAM or GelMA alone.

Impact Resistance Enhancement by Adding Core-Shell Particle to Epoxy Resin Modified with Hyperbranched Polymer.

A core-shell particle was fabricated by grafting amino-terminated hyperbranched polymer to the surface of silica nanoparticles. The influences of core-shell particle contents on the tensile and impact strength of the epoxy thermosets modified with amino-terminated hyperbranched polymer were discussed in detail. For comparison, core-shell particle was added into the epoxy/polyamide system for toughness improvement. Results from tensile and impact tests are provided. The introduction of core-shell particle into the epoxy/polyamide systems just slightly enhanced the tensile and impact strength. The incorporation of 3 wt % core-shell particle could substantially improve the tensile and impact strength of epoxy/amino-terminated hyperbranched polymer thermosets. Field emission-scanning electron microscope images of the impact fracture surfaces showed that the excellent impact resistance of epoxy/amino-terminated hyperbranched polymer/core-shell particle thermosets may be attributed to the synergistic effect of shearing deformation and crack pinning/propagation, which is induced by the good compatibility between epoxy matrix and core-shell particle in the presence of amino-terminated hyperbranched polymer.

[Immunofluorescence examination of CK-13 expression in cell line KB differentiated by all-trans retinoic acid or As2 O3].

OBJECTIVE: To examine the expression of cytokeratin-13 (CK-13) in oral squamous cell carcinoma (OSCC) and to discuss the effects of all-trans retinoic acid (ATRA) or arsenic trioxide (As2 O3) on the differentiation of human oral undifferentiated squamous cell carcinoma cell line KB cells. METHODS: The cultured KB cells were divided into three groups, ATRA group, As2 O3 group, and control. The expression of CK-13 in KB cells was detected using the immunofluorescence before and after KB cells were induced by ATRA or As2 O3. RESULTS: The expression rates of CK-13 in KB cells in the ATRA group and As2 O3 group were significantly higher than that in the control (P < 0.05), but there was no significant difference in the expression between ATRA and As2 O3 group(P > 0.05). CONCLUSIONS: ATRA and As2 O3 both have the ability to differentiate the KB cells, and the expression is associated with the degree of tumor differentiation. CK-13 may serve as a molecular marker to evaluate the effect of the differentiation treatment on OSCC.