No abstract

No abstract

The combination of oral antidiabetic drugs, pioglitazone, metformin, and glibenclamide, which also exhibit the strongest anti-inflammatory action among oral antidiabetic drugs, were loaded into chitosan/gelatin/polycaprolactone (PCL) by electrospinning and polyvinyl pyrrolidone (PVP)/PCL composite nanofibrous scaffolds by pressurized gyration to compare the diabetic wound healing effect. The combination therapies significantly accelerated diabetic wound healing in type-1 diabetic rats and organized densely packed collagen fibers in the dermis, it also showed better regeneration of the dermis and epidermis than single drug-loaded scaffolds with less inflammatory cell infiltration and edema. The formation of the hair follicles started in 14 days only in the combination therapy and lower proinflammatory cytokine levels were observed compared to single drug-loaded treatment groups. The combination therapy increased the wettability and hydrophilicity of scaffolds, demonstrated sustained drug release over 14 days, has high tensile strength and suitable cytocompatibility on L929 (mouse fibroblast) cell and created a suitable area for the proliferation of fibroblast cells. Consequently, the application of metformin and pioglitazone-loaded chitosan/gelatin/PCL nanofibrous scaffolds to a diabetic wound area offer high bioavailability, fewer systemic side effects, and reduced frequency of dosage and amount of drug.

In the present study, diffusion bonding was used to join Ti -6Al -4V alloy to a microduplex stainless steel using a pure copper interlayer. The effects of heating rate and holding time on microstructural developments across the joint region were investigated. After bonding, microstructural analysis including metallographic examination and energy dispersive spectroscopy (EDS), microhardness measurements, and shear strength tests were carried out. From the results, it was seen that heating rate and holding time directly affect microstructural development at the joint, especially with respect to the formation of TiFe intermetallic compounds, and this in turn affects the shear strength of the bonds. A sound bond was obtained with a heating rate of 100 K min 1 and holding time of 5 min, and this was related to the small amount of TiFe intermetallics formed close to the duplex stainless steel side at this bonding condition. Although Ti 2 Cu and TiFe intermetallics were formed in all specimens, it was seen that the most deleterious intermetallic was TiFe. As the heating rate was decreased and holding time increased the amount of TiFe intermetallics increased, and consequently shear strength decreased. As a result, from the microstructural observations, EDS analysis, microhardness measurements, and shear strength tests, it was concluded that a high heating rate and a short holding time must be used in the diffusion bonding of Ti -6Al -4V to a microduplex stainless steel when pure copper interlayers are used.M ST/4925

No abstract

Three groups of fluorene−dithieno[3,2-b;2′,3′-d]thiophene-S,S-dioxides (DTT-S,S-dioxide) copolymers, each having four different ratios of DTT-S,S-dioxide (5, 15, 25, and 50%) were successfully synthesized through Suzuki coupling method. While the first group copolymers P1 had direct connection of fluorene to the peripheral thiophenes of DTT-S,S-dioxide, second group copolymers P2 had a thiophene extension between fluorene and DTT-S,S-dioxide, and in the third group, copolymers P3, fluorene had a connection with DTT-S,S-dioxide through the phenyl moiety of DTT. Absorbance and emission measurements of first two groups P1 and P2 displayed a regular bathochromic shift with increasing content of DTT-S,S-dioxide, which was more clearly observed in their solid state fluorescence measurements. Introduction of thiophene to the peripherals of the DTT-S,S-dioxide in copolymers P2 caused even further bathochromic shift in absorbances and emissions. As the absorbance and emission of P1 went up to 447 and 558 nm in solution, respectively, P2 had them at 472 and 592 nm, respectively. In solid state, emissions of P1 and P2 even went further up to 585 and 646 nm, respectively. The bathochromic trend of P1 and P2 became opposite with absorbance and solid state emission of P3, which had a hypsochromic shift with increasing content of DTT-S,S-dioxide. Solid state emission of P3, particularly the copolymers having 5, 15 and 50% DTT-S,S-dioxide, covered a wide region between 400 and 675 nm. A spread of colors from light blue (border of white) to red through green and yellow was obtained with the OLED applications of the copolymers. Their optical and electronic band gaps varied between 2.17 and 2.99 eV and between 2.68 and 3.57 eV, respectively. While the highest quantum yield was obtained with P2 (5%) as 0.66, the lowest was observed with P2 (50%) as 0.03. Almost all of the polymers displayed good thermal stabilities. No weight loss was observed with the copolymers P2 (5−15%) and P3 up to 400 °C.

Synthesis of nanostructured thin films of pure and oxidized levan exopolysaccharide by matrix-assisted pulsed laser evaporation is reported. Solutions of pure exopolysaccharides in dimethyl sulfoxide were frozen in liquid nitrogen to obtain solid cryogenic pellets that have been used as targets in pulsed laser evaporation experiments with a KrF* excimer source. The expulsed material was collected and assembled onto glass slides and Si wafers. The contact angle studies evidenced a higher hydrophilic behavior in the case of oxidized levan structures because of the presence of acidic aldehyde-hydrogen bonds of the coating formed after oxidation. The obtained films preserved the base material composition as confirmed by Fourier transform infrared spectroscopy. They were compact with high specific surface areas, as demonstrated by scanning electron and atomic force microscopy investigations. In vitro colorimetric assays revealed a high potential for cell proliferation for all coatings with certain predominance for oxidized levan.

No abstract