Preparation of YSZ Coated AISI-Type 316L Stainless Steel by the Sol-Gel Coating Method and Its Corrosion Behavior in Molten Carbonate

The effect of heat-treatment conditions on the corrosion behavior of yttria stabilized zirconia (YSZ) coated AISI-type 316L stainless steels in molten carbonate are investigated. YSZ films on stainless steel were prepared by the sol-gel method. While the sample heat-treated at 800°C for 2 hours in air has an uneven surface microstructure with macrocracks, a YSZ coated sample heat-treated in argon has an even microstructure. The polarization resistance and corrosion rate of YSZ coated sample heat-treated in air were deteriorated from 6.948 cm² and 364.7 mpy (millimeter per year) to 3.291 cm² and 769.8 mpy, respectively, by the corrosion for 100 hours due to its poor surface microstructures. At the same experimental condition, meanwhile, those corrosion parameters of YSZ coated sample heat-treated in argon were 15.43 cm² and 164.2 mpy, respectively, and those were improved to 18.83 cm² and 134.6 mpy after the corrosion for 100 hours. This is attributed to the YSZ film with well developed surface microstructures. The concentration profiles of elements and X-ray diffractograms indicate that the oxide layer of YSZ coated sample heat-treated in argon had a triple layer structure composed of outer YSZ film, in between Fe₂O₃ layer, and inner chromium rich layer during corrosion.     

Instability of Statical Solutions of Steel 2D Frames in High Temperature

This work is intended as an attempt to stability analysis of static equations of flat steel frames in fire. High temperature during fire adversely affects on structural steel elements by activating irreversible processes (plasticity, creep). Rheological property can be described in simplified form by power term. Steel properties is represented by physical equations which contains three terms: linear (elasticity), nonlinear and rheological (related to creep). (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Organometallic Iridium(III) Complex Sensitized Ternary Hybrid Photocatalyst for CO2 to CO Conversion

A series of heteroleptic iridium(III) complexes functionalized with two phosphonic acid (−PO₃H₂) groups ( ^dfppy IrP , ^ppy IrP , ^btp IrP , and ^piq IrP ) were prepared and anchored onto rhenium(I) catalyst (ReP)-loaded TiO₂ particles (TiO₂/ReP) to build up a new IrP -sensitized TiO₂ photocatalyst system ( IrP /TiO₂/ReP). The photosensitizing behavior of the IrP series was examined within the IrP /TiO₂/ReP platform for the photocatalytic conversion of CO₂ into CO. The four IrP -based ternary hybrids showed increased conversion activity and durability than that of the corresponding homo- ( IrP +ReP) and heterogeneous ( IrP +TiO₂/ReP) mixed systems. Among the four IrP /TiO₂/ReP photocatalysts, the low-energy-light (>500 nm) activated ^piq IrP immobilized ternary system ( ^piq IrP /TiO₂/ReP) exhibited the most durable conversion activity, giving a turnover number of ≥730 for 170 h. A similar kinetic feature observed through time-resolved photoluminescence measurements of both ^btp IrP /TiO₂ and TiO₂-free ^btp IrP films suggests that the net electron flow in the ternary hybrid proceeds dominantly through a reductive quenching mechanism, unlike the oxidative quenching route of typical dye/TiO₂-based photolysis.     

Stereoselective synthesis and anticancer activity of broussonetine analogues

The stereoselective synthesis of two broussonetine analogues 14·HCl and ent-14·HCl with differing stereochemistry of the polyhydroxylated pyrrolidine core and a simple C₁₃ alkyl fragment has been achieved. For their construction, the known oxazolidinones 15 and 16 were chosen as appropriate advanced scaffolds. The common hydrophobic side chain was incorporated at an early stage of the synthesis through Grubbs’ cross metathesis chemistry. The required pyrrolidine skeleton was then formed by the cyclization of open chain intermediates 17 and 18. Four synthesized compounds were screened in vitro for antiproliferative/cytotoxic activity against six cancer cell lines by MTT assay. Compounds 14·HCl (HeLa and A-549) and ent-14·HCl (Caco-2 and Jurkat) showed comparable or higher potency than conventional anticancer agent cisplatin on at least two evaluated cancer cells, respectively.     

Dendritic macromers as in situ polymerizing biomaterials for securing cataract incisions

Dendritic macromers are attractive macromolecules for hydrogel formation since high cross-linking densities at low polymer concentration can be obtained, varied physical properties can be observed based on the macromer structure, and low viscous aqueous solutions can be injected in an in vivo site of irregular shaped to form a well-integrated polymer network. A peptide dendron possessing terminal cysteine residues was synthesized and characterized. When this peptide dendron was mixed with poly(ethylene glycol dialdehyde) in aqueous solution at pH = 7.4, a hydrogel spontaneously formed as a consequence of thiazolidine linkages between the macromers. Such in situ polymerized hydrogels are of interest for tissue engineering and wound-repair applications. To evaluate the potential use of this hydrogel sealant in ophthalmic surgeries, a 3-mm clear corneal incision (i.e., the wounds created during a typical cataract surgery) was successfully sealed.