Effect of Sr and Ti Addition on the Corrosion Behaviour of Al-7Si-0.3Mg Alloy

In the present study, the corrosion behaviour of A356 (Al-7Si-0.3Mg) alloy in 3.5% NaCl solution has been evaluated using cyclic/potentiodynamic polarization tests. The alloy was provided in the unmodified form and it was then modified with AlTi5B1 for grain refinement and with AlSr15 for Si modifications. These modifications yield to better mechanical properties. Tensile tests were performed. In addition, bifilm index and SDAS values were calculated and microstructure of the samples was investigated. As a result of the corrosion test, the Ecorr values for all conditions were determined approximately equal, and the samples were pitted rapidly. The degassing of the melt decreased the bifilm index (i.e. higher melt quality) and thereby the corrosion resistance was increased. The lowest corrosion rate was founded at degassing and as-received condition (3.9x10-3 mm/year). However, additive elements do not show the effect which degassing process shows

Computational fluid dynamics application in reducing complications of patent ductus arteriosus stenting

In some cases, especially in neonates, ductus arteriosus needs to remain patent for multiple medical purposes. In order to achieve this, current practice involves inserting stent in the ductus arteriosus. This condition is called patent duc-tus arteriosus (PDA). For this process, stents such as coronary stent are commonly used due to unavailability of customized stent for PDA in neonates. The usage of coronary stent however, opens the possibility of acute stent thrombosis and other complications. Therefore, there is a high need of special and customized stents to be used for PDA in neonates. This customized stent has to be able to sustain the hemodynamic effects of the flow inside the PDA. The stent has to be able to support the ductus wall compression and contraction due to arterial compliance. What is more important is that the stent must properly fit into various morphologies of the ductus. There are several different morphologies of PDA identified and the stents must be able to sustain the various shapes and tortuosity. In addition, the stent has to be tested for biocompatibility and practicality. Therefore, the customized design of the PDA stents can be derived from the concept of coronary stents and in compliance with all the mentioned characteristics. However, further analysis has to be completed ensure proper compatibility with neonates. In conclusion, the biggest challenge is to customize a stent that fits all the PDA morphologies

Grifola frondosa water extract alleviates intestinal inflammation by suppressing TNF-α production and its signaling

TNF-α is a major cytokine involved in inflammatory bowel disease (IBD). In this study, water extract of Grifola frondosa (GFW) was evaluated for its protective effects against colon inflammation through the modulation of TNF-α action. In coculture of HT-29 human colon cancer cells with U937 human monocytic cells, TNF-α-induced monocyte adhesion to HT-29 cells was significantly suppressed by GFW (10, 50, 100 µg/ml). The reduced adhesion by GFW correlated with the suppressed expression of MCP-1 and IL-8, the major IBD-associated chemokines. In addition, treatment with GFW significantly suppressed TNF-α-induced reactive oxygen species production and NF-κB transcriptional activity in HT-29 cells. In differentiated U937 monocytic cells, LPS-induced TNF-α production, which is known to be mediated through NF-κB activation, was significantly suppressed by GFW. In an in vivo rat model of IBD, oral administration of GFW for 5 days (1 g/kg per day) significantly inhibited the trinitrobenzene sulfonic acid (TNBS)-induced weight loss, colon ulceration, myeloperoxidase activity, and TNF-α expression in the colon tissue. Moreover, the effect of GFW was similar to that of intra-peritoneal injection of 5-aminosalicylic acid (5-ASA), an active metabolite of sulfasalazine, commonly used drug for the treatment of IBD. The results suggest that GFW ameliorates colon inflammation by suppressing production of TNF-α as well as its signaling through NF-κB leading to the expression of inflammatory chemokines, MCP-1 and IL-8. Taken together, the results strongly suggest GFW is a valuable medicinal food for IBD treatment, and thus may be used as an alternative medicine for IBD