No abstract

We study level lines of Gaussian Free Field h emanating from boundary points. The article has two parts. In the first part, we show that the level lines are random continuous curves which are variants of SLE 4 path. We show that the level lines with different heights satisfy the same monotonicity behavior as the level lines of smooth functions. We prove that the time-reversal of the level line coincides with the level line of −h. This implies that the time-reversal of SLE 4 (ρ) process is still an SLE 4 (ρ) process. We prove that the level lines satisfy "target-independent" property. In the second part, we discuss the relation between Gaussian Free Field and Conformal Loop Ensemble (CLE). A CLE is a collection of disjoint SLE-loops. Since the level lines of GFF are SLE 4 paths, the collection of level loops of GFF corresponds to CLE 4 . We study the coupling between GFF and CLE 4 with time parameter which sheds lights on the conformal invariant metric on CLE 4 . Primary 60G60; secondary 60J67.

Conventional biphasic calcium phosphate (BCP) bioceramics are facing many challenges to meet the demands of regenerative medicine, and their biological properties are limited to a large extent due to the large grain size in comparison with nanocrystalline of natural bone mineral. Herein, this study aimed to fabricate porous BCP ceramic spheres with nanocrystalline (BCP-N) by combining alginate gelatinizing with microwave hybrid sintering methods and investigated their in vitro and in vivo combinational osteogenesis potential. For comparison, spherical BCP granules with microcrystalline (BCP-G) and commercially irregular BCP granules (BAM, BCP-I) were selected as control. The obtained BCP-N with specific nanotopography could well initiate and regulate in vitro biological response, such as degradation, protein adsorption, bone-like apatite formation, cell behaviors, and osteogenic differentiation. In vivo canine intramuscular implantation and rabbit mandible critical-sized bone defect repair further confirmed that nanotopography in BCP-N might be responsible for the stronger osteoinductivity and bone regenerative ability than BCP-G and BCP-I. Collectedly, due to nanotopographic similarities with nature bone apatite, BCP-N has excellent efficacy in guiding bone regeneration and holds great potential to become a potential alternative to standard bone grafts in bone defect filling applications.

Extremely asymmetric wettability, high wetting selectivity, instantaneous superwetting behaviors (low transmembrane resistance), and superior resistance to chemicals and solvents are needed for Janus membranes for switchable oil/water separation. However, it is still challenging to obtain Janus membranes with such properties. In this study, a surface with metastable hydrophobicity is constructed on one side of the chemically stable superhydrophilic TiO 2 @PPS membrane by adjusting the hydrophobization depth and the morphology of the hydrophobic layer via a water−oil interfacial grafting. The prepared Janus membrane exhibits a high water contact angle difference of ∼150°between its two surfaces with maintaining the superior penetrability of the original membrane, which makes it capable to separate both oil-in-water and waterin-oil emulsions with high fluxes and accuracy. The separation efficiency is higher than 98% for the separation of the two kinds of emulsions. The fluxes of the surfactant-free toluene-in-water and water-in-toluene emulsions are up to 6.4 × 10 2 and 9.5 × 10 2 L m −2 h −1 , respectively. Furthermore, the Janus membrane exhibits desirable antifouling performance and reusability during usage.

BackgroundThe hierarchical porous structure and surface topography of calcium phosphate (CaP) bioceramics have a crucial impact on their osteoinductivity.PurposeTo fabricate a biomimetic bone graft with an interconnected porous structure analogous to that of trabecular bone and a bioactive nanostructured surface with excellent osteoinductive potential.Materials and methodsA biphasic CaP (BCP) substrate with highly porous structure was fabricated by an improved sponge replication method. Surface modification was performed by uniformly depositing a hydroxyapatite (HA) nanoparticle layer to create nHA-coated BCP scaffolds. The effects of these scaffolds on osteogenic differentiation of murine bone marrow-derived stem cells (BMSCs) were investigated in vitro, and their osteoinductivity was further assessed in vivo.ResultsThe BCP and nHA-coated BCP scaffolds had similar trabecular bone-like architectures but different surface structures, with mean grain sizes of ~55 nm and ~1 μm, respectively. Compared with the BCP substrate, the nHA-coated BCP scaffolds favored cell adhesion and promoted osteogenic differentiation of BMSCs, as evidenced by upregulated expression of osteogenic genes, enhanced alkaline phosphatase activity, and increased osteocalcin production. This could be attributed to activation of the BMP/Smad signaling pathway, as significantly higher expression levels of BMPRI, Smad1, Smad4, and Smad5 were observed in the nHA-coated BCP group. The nHA-coated BCP scaffold not only maintained scaffold integrity but also induced ectopic bone formation when implanted into rabbit dorsal muscle in vivo for 90 days, whereas the BCP substrate underwent marked biodegradation that led to severe inflammation with no sign of osteogenesis.ConclusionThe present study demonstrates the potential of this biomimetic bone graft with a trabecular framework and nanotopography for use in orthopedic applications.