Statistical analysis of geometrical parameters of corroded reinforcement

This paper reports an experimental work to investigate the pit corrosion of steel bars in chloride contaminated concrete. A total of 50 reinforcing steel bars with a length of 250 mm and a diameter of 14 mm were embedded in 10 concrete specimens, before they were subjected to accelerated corrosion. The geometric parameters of the corroded steel bars were then examined using 3D scanning method, before the characteristics of pitting corrosion of the corroded bars were analyzed accordingly. The results show that there is a weak correlation between the maximum pit depth and the mass loss rate. However, there is a strong correlation between the pitting factor and the mass loss rate. The relationship between the pitting factor and the mass loss rate has been developed as a reciprocal function

Overexpression of CCN3 inhibits inflammation and progression of atherosclerosis in apolipoprotein E-deficient mice.

BACKGROUND: Cysteine-rich 61/connective tissue growth factor/nephroblastoma overexpressed (CCN) 3 has been recently reported to play a role in regulating inflammation of vascular endothelial cells. However, the role of CCN3 in atherosclerosis, which is characterized by vascular inflammation, remains unclear. HYPOTHESIS AND OBJECTIVES: Overexpression of CCN3 may relieve the inflammation response in and inhibit the progress of atherosclerosis. We aimed to explore the potential roles of CCN3 in inflammation in atherosclerosis. STRATEGY AND MAIN RESULTS: In in vitro studies using cultured human aortic endothelial cells and human umbilical vein endothelial cells, CCN3 mRNA and protein expression significantly decreased in response to tumor necrosis factor-α and interleukin-1β treatments (p<0.05), when analyzed by quantitative real-time polymerase chain reaction and Western blot. Using a mouse model of atherosclerosis, the mRNA and protein levels of CCN3 decreased by 72.2% (p = 0.041) and 86.4% (p = 0.036), respectively, compared with levels in wild-type control mice, respectively. Overexpression of CCN3 by adenovirus-mediated gene overexpression decreased low-density lipoprotein cholesterol by 48.9% (p = 0.017), total cholesterol by 58.9% (p = 0.031), and triglycerides by 56.8% (p = 0.022), and it increased high-density lipoprotein cholesterol level by 2.16-fold (p = 0.039), compared with control groups. Additionally, a reduced plaque area and increased fibrous cap were observed (p<0.05). Furthermore, CCN3 overexpression decreased cell adhesion molecule-1 mRNA expression by 84.7% (p = 0.007) and intercellular adhesion molecule-1 mRNA expression by 61.2% (p = 0.044). Inflammatory factors, including matrix metalloproteinases, cyclooxygenase 2, and tissue factor also significantly (p<0.05) decreased with CCN3 overexpression in the atherosclerotic mouse model. Additionally, CCN1 and CCN2, which have been reported to be highly expressed in aortic atherosclerotic plaques, were significantly downregulated (p<0.05) by CCN3 overexpression. CONCLUSION: CCN3 overexpression is associated with control of inflammatory processes and reversion of dyslipidemia in the process of atherosclerosis, which implies that CCN3 may be a promising target in the treatment of atherosclerosis

Applicability Analysis of Assessment Methods for Morphological Parameters of Corroded Steel Bars

The irregular and uneven residual sections along the length of a corroded steel bar substantially change its mechanical properties and significantly dominate the safety and performance of an existing concrete structure. As a result, it is important to measure the geometry and amount of corrosion of a steel bar in a structure properly to assess the residual bearing capacity and service life of the structure. This paper introduces and compares five different methods for measuring the geometry and amount of corrosion of a steel bar. A single 500 mm long and 14 mm diameter steel bar is the specimen that is subjected to accelerated corrosion in this protocol. Its morphology and the amount of corrosion were carefully measured before and after using mass loss measurements, a Vernier caliper, drainage measurements, 3D scanning, and X-ray micro-computed tomography (XCT). The applicability and suitability of these different methods were then evaluated. The results show that the Vernier caliper is the best choice for measuring the morphology of a non-corroded bar, while 3D scanning is the most suitable for quantifying the morphology of a corroded bar

Effect of CCN3 overexpression on gene expression of adhesion molecules.

<p>qRT-PCR was used to analyze the mRNA levels of VCAM-1 (A) and ICAM-1 (B) in tissues of the left common carotid artery. *p<0.05 or **p<0.01 vs. PBS or Ad-GFP denotes a statistically significant difference.</p

Effect of proinflammatory cytokines on CCN3 expression.

<p>HAECs (A) and HUVECs (B) were treated with TNF-α (10 ng/ml) or IL-1β (4 ng/ml) for 24 h. Total RNA and cell protein were harvested for qRT-PCR or Western blot analysis, respectively. mRNA expression was normalized to GAPDH (<i>N</i> = 6, *p<0.05 and **p<0.01). Protein loading was normalized to equal amounts of cells.</p

Expression of CCN3 in atherosclerosis.

<p>The mRNA level (A) and protein level (B) of CCN3 in the left common carotid artery of mice were evaluated by qRT-PCR and Western blot analysis, respectively. 1 represents control mice (wild-type C57BL; 6 mice); 2 represents 25-week-old ApoE^−/− mice fed a high-fat diet. GAPDH was used as a control. *p<0.05, <i>N</i> = 30 per group.</p

Effect of CCN3 overexpression on CCN1 and CCN2 expression.

<p>The mRNA levels of CCN1 (A) and CCN2 (B) in tissues of the left common carotid artery were analyzed by qRT-PCR. *p<0.05 vs. PBS or Ad-GFP denotes a statistically significant difference.</p

Effect of overexpression of CCN3 on atherosclerosis.

<p>CCN3 mRNA (A) and protein (B) levels in different treatment groups of mice were analyzed by qRT-PCR and Western blot, respectively. PBS, mice injected with PBS as a control; Ad-GFP, mice injected with recombinant adenovirus expressing GFP as a non-specific control; Ad-CCN3, mice injected with recombinant adenovirus expressing CCN3. Serum levels of LDL cholesterol (C), HDL cholesterol (D), total cholesterol (E), and triglycerides (F) in the three groups of mice are shown. Cross-section histological analyses of plaques stained by HE (G) are shown. Quantitative analysis of plaque area (H), fibrous cap (I), cap-to-core ratio (J), and intima-media thickness (K) in the three groups of mice are also shown. *p<0.05 vs. PBS or Ad-GFP denotes a statistically significant difference.</p

Measurement Methods of Geometrical Parameters and Amount of Corrosion of Steel Bar

This paper aims to evaluate the applicability and suitability of the different methods, including weight loss, vernier caliper, drainage method, 3D scanning and XCT methods in the measurement of geometric parameters and amount of corrosion of a steel bar. A single 400mm long and 14.11mm diameter steel bar was measured first as non-corroded specimen before an accelerated corrosion of its 300mm long middle part took place. This was followed by the measurement and evaluation of the geometrical parameters of the same bar specimen within its 300mm long corroded part and 30mm non-corroded part at its right end using different methods. The results show that the geometrical parameters of a corroded bar measured using 3D scanning and XCT methods well matched each other and much more precise than those using weight loss, vernier caliper and drainage methods. 3D scanning is the most suitable method to measure the geometrical parameter of a corroded bar. Vernier caliper is the best option for measuring the geometrical parameter of a non-corroded bar