NADPH oxidase 4 mediates insulin-stimulated HIF-1α and VEGF expression, and angiogenesis in vitro

Acute intensive insulin therapy causes a transient worsening of diabetic retinopathy in type 1 diabetes patients and is related to VEGF expression. Reactive oxygen species (ROS) have been shown to be involved in HIF-1α and VEGF expression induced by insulin, but the role of specific ROS sources has not been fully elucidated. In this study we examined the role of NADPH oxidase subunit 4 (Nox4) in insulin-stimulated HIF-1α and VEGF expression, and angiogenic responses in human microvascular endothelial cells (HMVECs). Here we demonstrate that knockdown of Nox4 by siRNA reduced insulin-stimulated ROS generation, the tyrosine phosphorylation of IR-β and IRS-1, but did not change the serine phosphorylation of IRS-1. Nox4 gene silencing had a much greater inhibitory effect on insulin-induced AKT activation than ERK1/2 activation, whereas it had little effect on the expression of the phosphatases such as MKP-1 and SHIP. Inhibition of Nox4 expression inhibited the transcriptional activity of VEGF through HIF-1. Overexpression of wild-type Nox4 was sufficient to increase VEGF transcriptional activity, and further enhanced insulin-stimulated the activation of VEGF. Downregulation of Nox4 expression decreased insulin-stimulated mRNA and protein expression of HIF-1α, but did not change the rate of HIF-1α degradation. Inhibition of Nox4 impaired insulin-stimulated VEGF expression, cell migration, cell proliferation, and tube formation in HMVECs. Our data indicate that Nox4-derived ROS are essential for HIF-1α-dependent VEGF expression, and angiogenesis in vitro induced by insulin. Nox4 may be an attractive therapeutic target for diabetic retinopathy caused by intensive insulin treatment

Comparative performance evaluation of basalt fiber–modified hot in-place (HIP) recycling asphalt mixtures: site mixture versus lab mixture

The performance improvement of hot in-place recycling asphalt mixtures has been a hot topic recently due to the widespread application of HIP recycling technology. Based on the maintenance project of the provincial pavement G233 Baoying section, basalt fibers were introduced into HIP recycling mixtures. The effect of basalt fiber on the comprehensive performance of recycled mixtures was investigated using high temperature stability tests, cracking resistance tests, water stability tests, and dynamic modulus tests. Moreover, the performance of site mixtures was comparatively investigated with that of lab-made mixtures to further explore the site mixing effect on the mixture performance. The results showed that the recycled mixtures without basalt fiber presented unqualified cracking resistance even though proper mixture design was performed. The addition of basalt fibers could greatly enhance the rutting resistance, low-temperature cracking resistance, and stripping resistance of HIP recycled mixtures by 105.2%, 102.3%, and 46.9%, respectively. Moreover, the mixing method also had a significant impact on the properties of mixtures. The recycled mixtures produced by the site re-mixing method showed inferior performance compared to that of mixtures produced by the lab mixing method. Specifically, the dynamic stability, low temperature failure strain, and stripping point values reduced by 44.1%, 16.2%, and 11.7%, respectively, indicating that the site re-mixing process was not as effective as the lab mixing process due to the weaker blending and mixing procedures of the site equipment. The results could be beneficial for the utilization of basalt fiber in HIP recycling technology

Cyclic and Fragility Analysis of a Corroded Bridge Reinforced by Steel Plates under Mainshock and Aftershock Sequences

The corrosion of steel bars embedded in concrete structures results in the degradation of their structural capacity. In earthquake-prone zones, the corroded structure may be considerably vulnerable under mainshock–aftershock sequences relative to a single mainshock. Therefore, it is necessary to reinforce corroded structures to resist potential natural hazards. In this study, the effects of both pitting and uniform corrosion on the structural capacity of a bridge pier before and after strengthening were studied. Subsequently, the failure probability of a corroded bridge was calculated, which is conditional on the corrosion level, steel plate thickness, and ground-motion intensity. The findings implied that both pitting and uniform corrosions significantly reduced the capacity of the bridge pier, particularly pitting corrosion. The fragility curves showed that with an increased thickness of the steel plate, the probability of failure decreases if the intensity of the mainshock–aftershock sequences is higher than the threshold value. In addition, the threshold value has a high correlation with the thickness of the steel plate and the corrosion ratio

Prediction of Crack Resistance of LFSMA-13 with and without Anti-Rut Agent Using Parameters of FTIR Spectrum under Different Aging Degrees

This paper aims to better analyze the crack resistance of lignin fiber reinforced SMA-13 (LFSMA-13) asphalt mixtures, with and without polymer anti-rut agent (ARA), under different aging degrees. IDEAL-CT test and Fourier transform infrared (FTIR) spectroscopy were utilized to analyze the relationships between the crack resistance of LFSMA-13, with and without ARA, and the parameters of the FTIR spectrum of the asphalt extracted from the test samples. A convenient testing method to predict the anti-crack ability of the mixtures in a road was also derived in this study. The test samples were prepared using the specifications listed by AASHTO. The fracture formation work (Winitial) and cracking index (CTIndex) in the IDEAL-CT test were adopted to reflect the cracking ability of the asphalt mixtures in both the crack formation stage and the crack propagation stage. The peak areas of the FTIR spectrum were utilized to reveal the chemical properties of the asphalt material inside the SMA-13 asphalt mixtures, with and without ARA under different aging degrees. Grey correlation analysis was adopted to choose the most suitable FTIR spectrum parameters to derive the prediction models of Winitial and CTIndex under different aging degrees. After conducting a series of tests, the results showed that the aging process could well affect the crack resistance of the test samples and the peak areas of the asphalt extracted from the mixtures. The FTIR parameters selected from the grey correlation analysis could be used to well predict the anti-crack ability of the asphalt mixtures

Study on purification effect of infiltration materials to pavement runoff pollution

The concentrations of pollutants in pavement runoff are higher than those in other surface runoff normally, which causes serious problems in protecting the environment of receiving rivers and soils. According to the concept of low impact development (LID), a pavement runoff pollution control measure was developed by using infiltration structure. In order to infiltration structure play a superior role in the control of pavement runoff pollution, purification capacity of four typical infiltration materials was tested. Then, long-term purification efficiency of infiltration materials was explored to suspended solids. Besides, microscopic observation was performed on infiltration materials. Results indicated that purification effects of infiltration materials were significantly different. The purification process can be divided into three stages, which ware "rapid upgrading ", "slow upgrading " and "slow reduction ". Finally, Infiltration materials mainly have two modes to intercept runoff pollutants, which were pore adsorption and mechanical interception of the gap between materials

The Application of Acidic Electrolyzed Water to Grape Cultivation in the Southern Regions

Experimental studies have shown that AEW (Acidic Electrolyzed Water) plays a strong role in killing grape virus, and it has instantaneous, broad-spectrum, efficient, safe and non-residual fungicidal properties. The results show that spraying AEW, and spraying alkaline electrolyzed water first and then AEW, can play a good role in controlling the virus damage of grape downy mildew, Botrytis cinerea, anthracnose, grape Alternaria spot, and anthrachose of grape, with foliar control effect of 93.5%, 96.2%, 93.20%, 100% and 87.9%, respectively, and ear control effect of 88%, 92% , 84%, 84% and 72%, respectively. AEW can replace pesticide, and can promote the average grape weight and sugar degree

Suitability of Fiber Lengths for Hot Mix Asphalt with Different Nominal Maximum Aggregate Size: A Pilot Experimental Investigation

Fiber length is a key parameter for the mixture design of basalt fiber-reinforced hot mix asphalt (HMA), which significantly affects the mix performance. To evaluate the suitability of fiber lengths for HMA with different nominal maximum aggregate size (NMAS), basalt fiber with the lengths of 3, 6, 9, 12, and 15 mm were selected for dense graded gradations with different NMASs (namely, SUP-13, SUP-20, and SUP-25), so as to prepare the fiber-reinforced HMA mixtures. Then, the mix performance was evaluated by an indirect tensile asphalt cracking test (IDEAL-CT), a four-point bending beam fatigue test, a wheel tracking test, a uniaxial penetration test, a low temperature bending beam test, and a freeze-thaw splitting test. Based on the performance results, the optimum fiber length for each mix gradation was proposed by the normalization method. The results showed that adding basalt fiber can enhance the comprehensive performance of all three types of HMA to a great extent. Furthermore, fiber length presented remarkable impact on the crack resistance, the fatigue resistance of the HMA, and the low temperature crack resistance, but it had limited influence on the high temperature deformation resistance, and water stability. The optimum fiber length for SUP-13, SUP-20, and SUP-25 was 6, 9, and 12 mm, respectively

Study and Verification of a New Method to Test the Bonding Ability between Basalt Fiber and Asphalt Mortar

The bonding ability between basalt fiber bundle and asphalt mortar has a great influence on the properties of basalt fiber reinforced asphalt mixtures, yet the studies about the bonding between them is very limited. In this paper, a new test instrument called fiber-asphalt pulling machine and a new index called the nominal bonding stress (NBS) were designed and adopted to test and reveal the bonding between basalt fiber bundle and asphalt mortar. The procedures and rationality analysis of this new experiment was specified in this paper. In order to verify the reliability of the NBS index, the NBS values derived from this new test method and the rheological property indexes values of asphalt mortar under different powder–cement ratios were adopted to analyze the correlation between them. Two kinds of basalt fibers produced by two different manufacturers were adopted to conduct the parallel experiment. The results show that the nominal bonding stress between basalt fiber and asphalt mortar derived from this new test has a great correlation with the rheological properties of asphalt mortar, which also proves the credibility of this new test method and the NBS index

Aging Characteristics of Rubber Modified Asphalts in Different Environmental Factors Combinations

Two kinds of rubber modified asphalts were investigated and compared with virgin asphalt. In order to get closer to engineering practice, different combinations of four environmental factors were merged into the laboratory aging simulation. Subsequently, conventional property tests, including softening point, viscosity, creep stiffness, creep rate, and fatigue cracking were conducted on asphalt samples. The performance difference of asphalt before and after aging was selected as an evaluation index for asphalt aging degree. The results indicate that two kinds of rubber modified asphalts show stronger resistant ability to temperature deformation and better resistance to traffic loading than virgin asphalt in all kinds of environmental factors combinations. Tests on chemical analyses were conducted to investigate the asphalt aging characteristics. The apparent morphology of rubber modified asphalts are described in detail under an environment scanning electron microscope (ESEM). The damage condition reflected in images reveals the aging degree caused by multiple environmental factors. Moreover, the thermogravimetric analysis (TG) confirms that three kinds of asphalts can maintain thermal stability in various environments. Additionally, new characteristic functional groups were not detected in the infrared (IR) spectra of rubber modified asphalts, which means they have stable antioxidant properties given that their oxidation degrees change slightly throughout the aging processes