Due to its excellent biological and mechanical properties, silk fibroin has been intensively explored for tissue engineering and regenerative medicine applications. However, lack of translational evidence has hampered its clinical application for tissue repair. Here a silk fibroin film is developed and its translational potential is investigated for skin repair by performing comprehensive preclinical and clinical studies to fully evaluate its safety and effectiveness. The silk fibroin film fabricated using all green chemistry approaches demonstrates remarkable characteristics, including transmittance, fluid handling capacity, moisture vapor permeability, waterproofness, bacterial barrier properties, and biocompatibility. In vivo rabbit full-thickness skin defect study shows that the silk fibroin film effectively reduces the average wound healing time with better skin regeneration compared with the commercial wound dressings. Subsequent assessment in porcine model confirms its long-term safety and effectiveness for full-thickness skin defects. Finally, a randomized single-blind parallel controlled clinical trial with 71 patients shows that the silk fibroin film significantly reduces the time to wound healing and incidence of adverse events compared to commercial dressing. Therefore, the study provides systematic preclinical and clinical evidence that the silk fibroin film promotes wound healing thereby establishing a foundation towards its application for skin repair and regeneration in the clinic.

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Differing from the conventional micelles made of block or graft copolymers, in which the core and corona are connected by covalent bonding, the micelles reported in this paper are composed of a polymer pair and the core and corona are connected by hydrogen bonding. Poly(styrene-co-methacrylic acid) (SMAA) and poly(vinylpyrrolidone) (PVPo) self-assembled into spherical micelles with hydrodynamic radii around 100 nm in aqueous medium. These stable micelles are composed of the core of collapsed SMAA chains and the corona of solvated PVPo chains. The hydrogen bonding between methacrylic acid and PVPo units and the difference in the solubility in water between SMAA and PVPo are the main factors responsible for the micelle formation. Using dynamic light scattering, it was found that the hydrodynamic radius of the micelles significantly increases with increasing initial concentrations of both SMAA and PVPo. The micelle size dose not depend on the MAA content (3.55-13.1 mol %) in SMAA monotonically, which can be rationalized by the coexistence of different stabilization mechanisms. Transmission electronic microscopy (TEM) was used to observe morphologies of the micelles. The core-shell structure of the micelles became visualized only when adequate staining of the TEM specimens was employed.

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Increasing evidence has revealed that the surface characteristics of biomaterials, such as chemical composition, stiffness, and topography, especially nanotopography, significantly influence cell growth and differentiation. In this study, we examined the effect of surface biomimetic apatite nanostructure of a new hydroxyapatite-coated genipin-chitosan conjugation scaffold (HGCCS) on cell shape, cytoskeleton organization, and osteogenic differentiation of rat bone marrow-derived mesenchymal stem cells in vitro. Cell shape and cytoskeleton organization showed significant differences between cells cultured on genipin-cross-linked chitosan framework and those cultured on HGCCS with surface apatite network-like nanostructure after 7 days of incubation in the osteogenic medium. The result of specific alkaline phosphatase activity as an indicator of osteogenic differentiation showed that the alkaline phosphatase activity of rat bone marrow-derived mesenchymal stem cells was higher on HGCCS. Based on quantitative real-time polymerase chain reaction, HGCCS induced highest mRNA expression of osteogenic differentiation makers, runt-related transcription factor 2 by 7 days, osteopontin by 7 days, and osteocalcin by 14 days, respectively. The enhanced ability of cells on HGCCS to produce mineralized extracellular matrix and nodules was also assessed on day 14 with Alizarin red staining. The results of this study suggest that the surface biomimetic apatite nanostructure of HGCCS is a critical signal cue to promoting osteogenic differentiation in vitro. These findings open a new research avenue to controlling stem cell lineage commitment and provide a promising scaffold for bone tissue engineering.

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A three-dimensional mathematical model has been developed to simulate the compressible jets flow from the top-blown lance with multi-nozzles in converter to a free surrounding domain. The variations of fluid density and viscosity, high temperature, and Mach number were taken into consideration in this model which was validated against the physical modeling results. More specifically, computations were obtained to compare the widely used realizable k-e turbulence model against the standard k-w turbulence model, which shows that the latter one is superior to calculate diverse turbulent conditions within the multiple jets. Moreover, the coalescence pattern of the multiple jets has been illustrated by their Mach number distribution, and each individual jet proceeds in a curve course, bending to the lance center and tending to unite. The effects of the inclination angles on the jets coalescence were also investigated, which indicates that the lower the inclination angle is, the stronger the interfering extent between the multiple jets is. With the help of this model, the dynamic power of the multiple jets to support the cavity formation was demonstrated, and additionally, a mathematical model concerning the effective penetration radius and digressing path of the multiple jets was proposed by taking the inclination angle and the axial distance from the nozzle tips as arguments.KEY WORDS: BOF; top blowing; multiple jets; coalescence; inclination angle; CFD; turbulence model; three dimensional simulation. 491© 2010 ISIJ under the commercial conditions to analyses their essentials in detail, for example the jet coalescence pattern. As imagined, the jet coalescence, if it occurs, reduces the impact of the individual jet as the jets engulf a huge mass of ambient medium. Jet coalescence is thus considered detrimental. Furthermore, wide ranges of Reynolds and Mach numbers in the converter strengthen the complex characteristics of the jets. In order to study the pattern of the jets interference extent and their influence on the metal bath, there are a lot of efforts required to make in the establishment of an accurate numerical method for the multiple jets in the LD vessel.This article proposes a three-dimensional mathematical model aimed to simulate the supersonic free-surrounding jets flow from a lance assumed under the converter conditions, which is verified with physical modeling data.12) A 4-De-Laval-nozzles lance with prescribed nozzle configurations was put into use with inclination angles of 10°, 12°a nd 14°. First, this computational model and its mathematical equations are described. Thereafter, the final 3D simulating results of the jet regimes as well as physical data or semi-analytical method for confirming the model are presented. Finally, the fluid flow field of characteristic parameters, the jet coalescence pattern, and the usefulness of these results on an augmented knowledge for a top-blown process are discussed. Computational Model 2.1. Numerical AssumptionsIn order to formulate the transport equations for ...