Failure risk of recycled aggregates concrete

In the sustainable development context, the use of demolition waste increases in the building industry. Recycled aggregates from the demolition of concrete structures are then mixed in new concrete. Furthermore, the performance evaluation of a these recycled aggregate concrete (RAC) mix is not only limited to the determination of its conventional mechanical properties. The failure risk of concrete elements in structures made from RAC needs a comprehensive analysis. For that, a study on the fracture process of RAC has been performed and compared with that of normal concrete of the same structural class. Acoustic emission technique and digital correlation method have been used to follow the cracking process. Also, a new modelling approach for the fracture behaviour of RAC at the mesoscopic scale has been developed. It has taken into account the old attached mortar surrounding recycled aggregates. Results show that RAC has a more brittle behaviour than ordinary concrete and the numerical analysis shows that cracks growth through the recycled aggregates which have brittleness behaviour

Characteristics of anticancer drug studies registered on the Chinese Clinical Trial Registry (ChiCTR) from 2007 to 2015

Objective: This research aims to examine the basic and methodological characteristics of anticancer drug studies registered on the Chinese Clinical Trial Registry (ChiCTR) and explores the progress of implementation of good clinical practice (GCP) and the challenges it poses for anticancer drug research in China. Methods: The studies from 2007 to 2015 were downloaded from the ChiCTR and those involving anticancer drugs with evaluation of the main dimensions. The numerical trend of the studies registered each year was analyzed. Chi-square tests were performed to test for significant differences between different funding sources, types of drug and study phases. Results: Six hundred and four anticancer drug studies were collected. The overall number of anticancer drug studies was increased. Significant differences could be seen in the dimensions of multicentre study (P = 0.000), participant number (P = 0.029) and randomization procedure (P = 0.005) for the three funding sources. There were significant differences in the dimensions of multicentre study (P = 0.001), participant number (P = 0.025), collecting samples from participants (P = 0.006), and randomization procedure (P = 0.009) between different kinds of drugs. There were also significant differences in the dimension of participant number (P = 0.025) and randomization procedure (P = 0.016) between different study phases. Conclusion: There are problems with study registry criteria and study type classification method. Also, within the studies researched, heterogeneity exists for various dimensions. Different sources of funding, distinct types of drug and disparate phases of study lead to significant differences in certain dimensions of anticancer drug studies

Failure risk of recycled aggregates concrete

In the sustainable development context, the use of demolition waste increases in the building industry. Recycled aggregates from the demolition of concrete structures are then mixed in new concrete. Furthermore, the performance evaluation of a these recycled aggregate concrete (RAC) mix is not only limited to the determination of its conventional mechanical properties. The failure risk of concrete elements in structures made from RAC needs a comprehensive analysis. For that, a study on the fracture process of RAC has been performed and compared with that of normal concrete of the same structural class. Acoustic emission technique and digital correlation method have been used to follow the cracking process. Also, a new modelling approach for the fracture behaviour of RAC at the mesoscopic scale has been developed. It has taken into account the old attached mortar surrounding recycled aggregates. Results show that RAC has a more brittle behaviour than ordinary concrete and the numerical analysis shows that cracks growth through the recycled aggregates which have brittleness behaviour

Development of Sustainable Engineered Cementitious Composites by Incorporating Local Recycled Fine Aggregate

In this study, sustainable engineered cementitious composites (ECC) exhibiting high tensile strength as well as high tensile strain capacity were successfully developed by incorporating polyethylene (PE) fiber, local recycled fine aggregate (RFA), and limestone calcined clay cement (LC3). The improvement in tensile strength and tensile ductility was attributed to the self-cementing properties of RFA as well as the pozzolanic reaction between calcined clay and cement. Carbonate aluminates were also generated owing to the reaction between calcium carbonate in limestone and the aluminates in both calcined clay and cement. The bond strength between fiber and matrix was also enhanced. At the age of 150 days, the tensile stress-strain curves of ECC containing LC3 and RFA shifted from a bilinear model to a trilinear model, and the hydrophobic PE fiber exhibited hydrophilic bonding performance when embedded in RFA-LC3-ECC matrix, which could be explained by the densified cementitious matrix as well as the refined pore structure of ECC. Moreover, the substitution of ordinary Portland cement (OPC) by LC3 resulted in energy consumption and equivalent CO2 emission reduction ratios of 13.61% and 30.34%, respectively, when the replacement ratio of LC3 is 35%. Therefore, PE fiber-reinforced RFA-LC3-ECC demonstrates excellent mechanical performance as well as considerable environmental benefits

Mechanical Performance and Constitutive Model Analysis of Concrete Using PE Fiber-Strengthened Recycled Coarse Aggregate

To promote the sustainable development of the construction industry, concrete incorporating polyethylene (PE) fiber-strengthened recycled coarse aggregate (SRCA) and seawater and sea sand (SWSS) is prepared. The usage of SRCA significantly improves the mechanical performance of concrete. The strength is improved, and the failure mode of concrete cylinders is also remarkably altered. The incorporation of SWSS that alleviates the shortage of freshwater and river sand slightly reduces the mechanical strength of concrete at 28 and 90 days, while the replacement of cement by 35% limestone calcined clay cement (LC3) overcomes this drawback. The compressive strength of concrete is further enhanced, and the pore structure is refined. The introduction of LC3 also promotes the formation of Friedel’s salt, which could improve the chloride binding capacity of concrete using SWSS. Furthermore, the stress-strain relationship of sustainable concrete is analyzed, and the experimental results are compared with the commonly used constitutive models. The predictive constitutive models are proposed to effectively describe the mechanical performance of sustainable concrete

Multiscale Investigation on the Performance of Engineered Cementitious Composites Incorporating PE Fiber and Limstone Calcined Clay Cement (LC3)

Limestone calcined clay cement (LC3) is successfully used to fabricate engineered cementitious composites (ECC) exhibiting tensile strength σtu of 9.55 ± 0.59 MPa or tensile strain capacity εtu of 8.53 ± 0.30%. The high tensile strength of the composites is closely related to the improvement of fiber/matrix interfacial bond strength, and the high ductility is attributed to the enhancement of fiber dispersion homogeneity. For the case of ECC incorporating 50% LC3, the reduction of initial cracking stress σtc that favors the growth of the crack in a controlled manner also contributes to the improvement of strain hardening behavior. The composition analysis indicates that carboaluminates and additional hydration products including C-(A)-S-H and ettringite are generated, which contributes to the densification of the microstructure of the ECC matrix. The pore structure is thus remarkably refined. Besides, when ordinary Portland cement (OPC) is partly replaced by LC3, the consumed energy and equivalent CO2 emission decrease, especially the equivalent CO2 emission with the reduction ratio attaining 40.31%. It is found that ECC using 35% LC3 exhibits the highest mechanical resistance and ECC incorporating 50% LC3 shows the highest ductility from the environmental point of view

Cediranib Induces Apoptosis, G1 Phase Cell Cycle Arrest, and Autophagy in Non-Small-Cell Lung Cancer Cell A549 In Vitro

Lung cancer remains the leading cause of cancer death worldwide. Late diagnosis, chemoresistance, and metastasis are the main reasons for the high mortality rate of lung cancer. Therefore, the development of other treatments is urgent. Cediranib (CED), a vascular endothelial growth factor receptor (VEGFR) kinase inhibitor, shows promising antitumour activities in various cancers including lung cancer. Here, we explored the effects and the underlying molecular mechanism of CED on non-small-cell lung cancer (NSCLC) cell line A549 cells in vitro. Our results show that CED could inhibit A549 cell proliferation and cloning formation. Meanwhile, G1 phase cell cycle arrest was also found, as featured by the increased proportion of G1 phase cells as well as the reduction of G1 phase relative proteins CDK4/cyclin D1 and CDK2/cyclin E. Moreover, the ratio of LC3-II/LC3-I was elevated significantly in CED-treated groups compared with the controls. Furthermore, the expression of p-Akt, p-P38, p-Erk1/2, and p-mTOR proteins was decreased obviously in the treatment groups. These results suggest that CED could induce apoptosis and G1 phase cell cycle arrest in A549 cells. Meanwhile, CED may induce autophagy through MAPK/Erk1/2 and Akt/mTOR signal pathway in A549 cells

Experimental Investigations on Bond Behavior between FRP Bars and Advanced Sustainable Concrete

In response to resource shortage and carbon dioxide emissions, an innovative type of sustainable concrete containing LC3, seawater, sea sand, and surface-treated recycled aggregates is proposed in this study to replace traditional concrete. To understand the bond properties between the sustainable concrete and CFRP bars, an investigation was conducted on the bond behavior between sand-coated CFRP bars and advanced sustainable concrete. Pull-out tests were carried out to reveal the failure mechanisms and performance of this bond behavior. The results showed that the slip increased monotonically along with the increase in confinement. The bond strength increased up to approximately 15 MPa, and the critical ratio of C/D was reached. The critical ratio approached 3.5 for the Portland cement groups, while the ratio was determined as approximately 4.5 when LC3 was introduced. When the proportion of LC3 reached 50%, there was a reduction in bond strength. A multisegmented modified bond–slip model was developed to describe the four-stage bond behavior. In terms of bond strength and slip, the proposed advanced concrete exhibited almost identical bond behavior to other types of concrete

Screening of Alfalfa Varieties Resistant to <i>Phytophthora cactorum</i> and Related Resistance Mechanism

Alfalfa is one of the most important legume forages in the world. Root rot caused by soil-borne pathogens severely restricts the production of alfalfa. The knowledge of the interaction between alfalfa and root rot-pathogens is still lacking in China. Phytophthora cactorum was isolated from symptomatic seedlings of an alfalfa field in Nanjing with high levels of damping-off. We observed the different infection stages of P. cactorum on alfalfa, and found that the purified P. cactorum strain was aggressive in causing alfalfa seed and root rot. The infecting hyphae penetrated the epidermal cells and wrapped around the alfalfa roots within 48 h. By evaluating the resistance of 37 alfalfa cultivars from different countries to P. cactorum, we found Weston is a resistant variety, while Longdong is a susceptible variety. We further compared the activities of various enzymes in the plant antioxidant enzyme system between Weston and Longdong during P. cactorum infection, as well as gene expression associated with plant hormone biosynthesis and response pathways. The results showed that the disease-resistant variety Weston has stronger antioxidant enzyme activity and high levels of SA-responsive PR genes, when compared to the susceptible variety Longdong. These findings highlighted the process of interaction between P. cactorum and alfalfa, as well as the mechanism of alfalfa resistance to P. cactorum, which provides an important foundation for breeding resistant alfalfa varieties, as well as managing Phytophthora-caused alfalfa root rot

Screening of Alfalfa Varieties Resistant to Phytophthora cactorum and Related Resistance Mechanism

Alfalfa is one of the most important legume forages in the world. Root rot caused by soil-borne pathogens severely restricts the production of alfalfa. The knowledge of the interaction between alfalfa and root rot-pathogens is still lacking in China. Phytophthora cactorum was isolated from symptomatic seedlings of an alfalfa field in Nanjing with high levels of damping-off. We observed the different infection stages of P. cactorum on alfalfa, and found that the purified P. cactorum strain was aggressive in causing alfalfa seed and root rot. The infecting hyphae penetrated the epidermal cells and wrapped around the alfalfa roots within 48 h. By evaluating the resistance of 37 alfalfa cultivars from different countries to P. cactorum, we found Weston is a resistant variety, while Longdong is a susceptible variety. We further compared the activities of various enzymes in the plant antioxidant enzyme system between Weston and Longdong during P. cactorum infection, as well as gene expression associated with plant hormone biosynthesis and response pathways. The results showed that the disease-resistant variety Weston has stronger antioxidant enzyme activity and high levels of SA-responsive PR genes, when compared to the susceptible variety Longdong. These findings highlighted the process of interaction between P. cactorum and alfalfa, as well as the mechanism of alfalfa resistance to P. cactorum, which provides an important foundation for breeding resistant alfalfa varieties, as well as managing Phytophthora-caused alfalfa root rot