Quantification of Large Deformation with Punching in Dual Phase Steel and Change of its’ Microstructure – Part II: Local Strain Mapping of Dual Phase Steel by a Combination Technique of Electron Backscatter Diffraction and Digital Image Correlation Methods

To evaluate heterogeneous strain distribution developed by pre-deformations in dual phase (DP) steel accurately, a combinational technique of Electron Backscatter Diffraction (EBSD) and Digital Image Correlation (DIC) methods was newly introduced in this study. A good correlation is established between kernel average misorientation calculated by EBSD and local equivalent strain measured by DIC in ferrite matrix of DP steels regardless of the difference in deformation process, which means that an EBSD orientation map can be easily converted into an applicative strain map by employing the individual correlation formula. This new technique reveals that very large strain region is locally formed within dozens of micrometer from the punched edge in a punched DP steel. On the other hand, hard martensite grains dispersed in DP steel remarkably promote the heterogeneity of strain distribution in ferrite matrix. As a result, the large strain region is also developed in the form of bands in a cold-rolled DP steel by only 60% thickness reduction at least, as if it is affected by the distribution and morphology of martensite grains. In addition, the local strain mapping demonstrates that the equivalent strain of the large strain band in cold-rolled material is comparable to that of the heavily deformed edge in punched one. The very large strain band in ferrite matrix is characterized by ultrafine grained structure, which leads to the possibility for the losing ductility in ferrite matrix and the martensite cracking

Oral infection-inflammatory pathway, periodontitis, is a risk factor for endothelial dysfunction in patients with coronary artery disease

Objective: Several studies have shown that periodontitis is a risk factor for cardiovascular diseases. There is an association between inflammation and endothelial dysfunction. The purpose of this study was to evaluate endothelial function in patients with coronary artery disease (CAD) who had periodontitis. Methods and results: We evaluated forearm blood flow (FBF) responses to acetylcholine (ACh), an endothelium-dependent vasodilator, and to sodium nitroprusside (SNP), an endothelium-independent vasodilator, in 101 CAD patients with periodontitis (37 men and 11 women, 63 +/- 12 yr) and without periodontitis (36 men and 17 women, 62 +/- 13 yr). FBF was measured by using strain-gauge plethysmography. Circulating levels of C-reactive protein and interleukin-6 were significantly higher in the periodontitis group than in the non-periodontitis group. FBF response to ACh was significantly smaller in the periodontitis group than in the non-periodontitis group. SNP-stimulated vasodilation was similar in the two groups. Periodontal therapy reduced serum concentrations of C-reactive protein from 2.7 +/- 1.9 to 1.8 +/- 0.9 mg/L (P < 0.05) and interleukin-6 from 2.6 +/- 3.4 to 1.6 +/- 2.6 ng/L (P < 0.05) and augmented ACh-induced vasodilation from 14.7 +/- 5.2 to 20.1 +/- 6.1 mL/(min 100 mL) tissue (P < 0.05) in patients with periodontitis. The SNP-stimulated vasodilation was similar before and after treatment. After administration of NG-monomethyl-l-arginine, a nitric oxide synthase inhibitor, FBF response to ACh was similar before and after treatment. Conclusion: These findings suggest that periodontitis is associated with endothelial dysfunction in patients with CAD through a decrease in nitric oxide bioavailability. Systemic inflammation may be, at least in part, a cause and predictor of progression of endothelial dysfunction