Fatigue crack in large-scale tubular joints for offshore structures

Tubular members have been used for constructing offshore structures. Large-scale fatigue tests of welded tubular K-joints under the balanced in-plane bending brace were carried out to investigate the fatigue behavior of API 2W Gr.50 steel produced by POSCO. The experimental results were verified by numerical approaches and compared with the IIW, DnV RP-C203 and API RP 2A-WSD design curves. The test results based on the hot spot stress were in agreement with the design curves. The SCF factor for tubular K-jo...     

Study of Aromatic Compounds Derived from Sugarcane Bagasse. Part I: Effect of pH

This work aims at increasing the knowledge about the recovery of aromatic compounds from the lignin fraction of sugarcane bagasse, as well as exploring the possibility to recover these fine chemicals of great concern for many industrial sectors. The major natural products contained in the lignin fraction of such a straw material were extracted in previous work by alkaline hydrolysis using different concentrations of NaOH and amounts of bagasse, and HPLC analyses revealed that the extracts mainly contained p‐coumaric acid, ferulic acid, syringic acid, and vanillin, the first three containing and the last lacking a carboxyl group. All these aromatic compounds have well‐known antioxidant power and are very important in pharmacology. For these reasons, they have been investigated in this study by UV spectrophotometry, with special concern to the pH effect on their spectra and determination of their pK_a values.     

Middle latency auditory evoked potentials in epilepsy

Heparin (HE) exhibited a protective effect on liposome peroxidation induced by Fe2+ and Cu2+, decreasing the formation of both conjugated dienes and thiobarbituric acid reactive substances (TBARS) in a dose-dependent manner. The antioxidant activity was more relevant in the oxidizing system employing Fe2+ and H2O2 and generating the highly reactive OH radical. The analysis of liposome size distribution by quasielastic laser light scattering showed that: (1) the native structure of the particles was completely lost after exposure to Fenton reagent; (2) the presence of HE in the reaction mixture completely prevented the peroxidative damage on liposomes. Thus, HE acts as an antioxidant factor on membrane lipid bilayer. This suggests that HE, released from mast-cell granules during inflammatory processes, might locally protect the cell membrane from the oxidative injuries.