The potential of electrospun pullulan/dextran (P/D) nanofibers (average diameter = 323 nm) for vascular tissue engineering applications is explored. The mechanical properties of the nanofibers are of the same order of magnitude as that of human arteries (Young's modulus ≈0.88 MPa; tensile strength ≈0.35 MPa). It is demonstrated that the nanofiber topography enables cell adhesion and that the endothelial phenotype is maintained on the nanofibers. Moreover, P/D nanofibers support a stable confluent monolayer of endothelial cells over 14 d. SMCs seeded on nanofibers display similar levels of alpha smooth muscle actin and a lower proliferation rate than cells on 2D cultures. The observations suggest that nanofibers promote a shift to a quiescent contractile phenotype in SMCs.
The first total syntheses of (−)-syringolide 3, (+)-syributin 3 and their unnatural enantiomers (+)-syringolide 3 and (−)-syributin 3 using a common intermediate as starting material are described. In addition, total syntheses of (−)- and (+)-syributins 1 and 2 were accomplished by means of the same methodology. 相似文献
We investigated the structure and stability of dodecane-in-water emulsions stabilised by partially hydrophobised silica particles after dilution of the emulsions in solutions of sodium dodecyl sulfate and sodium chloride. The emulsions were stable to coalescence on dilution in salt solutions, but did cream over time. The rate and extent of creaming gradually decreased as the salt concentration in the diluted emulsion increased. Dilution in low concentrations of the anionic surfactant did not affect the emulsion stability to coalescence or alter the creaming behaviour of the emulsion. At surfactant concentrations above the critical micelle concentration, however, the rate and extent of creaming and flocculation of the drops were enhanced. 相似文献
The surface modification of lamellar silica prepared by liquid crystal templating has been investigated. Two hydrophilic surface modifier agents, 2-glycidoxypropyltrimethoxysilane and 2-[methoxy(polyethyleneoxy)propyl)]trimethoxysilane, have been tested. Characterizations of the modified silica include thermal analysis, (13)C and (29)Si solid state NMR, transmission electron microscopy (TEM) and X-ray diffraction (XRD). The different characterizations confirmed the preservation of the lamellar morphology and the successful surface modification with both silanes along with the template elimination. The results also indicate that the structure and length of the silanes influence the final lamellar organization as well as the grafting yields and mechanisms. 相似文献
The reaction of [TiIV(Cp)2Cl2] (Cp− = η5-C5H5−) and 2,6-bis(3,5-dimethylpyrazolyl-1-yl)pyridine (bdmpp) in Me2CO has afforded complex [TiIVCl2(O2)(bdmpp)] (1). The complex can also be prepared from the 1:1:1 [Ti(Cp)2Cl2]/bdmpp/H2O2 reaction mixture in various solvents. Single-crystal, X-ray crystallography has revealed that the TiIV center is in a distorted pentagonal bipyramidal environment in both of the two, crystallographically independent molecules that are present in the asymmetric unit; the equatorial positions are occupied by the two O atoms of the side-on (η2) O22− group and the three N-atoms of the tridentate chelate, while the two chloro ligands are on the axial positions. IR, Raman, electronic and 1H NMR data are discussed in terms of the known structure and the coordination modes of the peroxo and bdmpp ligands. 相似文献
The initial employment of pyridine-3-carbaldehyde oxime, (3-py)C(H)NOH, and pyridine-4-carbaldehyde oxime, (4-py)C(H)NOH, in zinc(II) carboxylate chemistry is reported. The syntheses, crystal structures and IR characterization are described for [Zn3(O2CPh)6{(3-py)C(H)NOH}2] (1) and [Zn2(O2CPh)4{(4-py)C(H)NOH}2] (2). The trinuclear molecule of 1 has a linear structure, with one monoatomically bridging η1:η2:μ and two syn, syn-η1:η1:μ benzoate groups spanning each pair of ZnII ions; the terminal metal ions are each capped by one (3-py)C(H)NOH ligand coordinating through its pyridyl nitrogen. Complex 2 exhibits a dinuclear paddle–wheel structure with a Zn···Zn distance of 2.990(2) Å; each ZnII ion has a square pyramidal geometry with four carboxylate oxygens in the basal plane and the pyridyl nitrogen of one monodentate (4-py)C(H)NOH ligand at the apex. Both complexes form 1D architectures by virtue of hydrogen bonding interactions involving the free oxime group as donor and the oxime nitrogen (1) or carboxylate oxygens (2) as acceptors. IR data are discussed in terms of the known structures and coordination modes of the ligands. 相似文献