Accelerated industrialization and urbanization have severely increased the consumption of cement and natural sand in construction, so it is of great significance to find suitable, green, and sustainable alternative materials to protect the ecological environment and promote sustainable development in the construction field. In this work, sustainable geopolymer mortar was fabricated by mixing manufactured sand prepared from limestone with the precursor consisting of fly ash (FA), metakaolin (MK) and the alkali-activator solution composed of NaOH and Na2SiO3 solution by the polymerization reaction. Besides, the influence of FA dosage (15

Understanding the influence of high temperature on reservoir rocks is necessary for the repair and reinforcement of high-temperature rock engineering. In this study, X-ray diffraction (XRD) tests, scanning electron microscope (SEM) tests, Brazilian splitting tests, and morphological scanning tests were performed on Cretaceous granite (CG), Jurassic granite (JG), and Jurassic sandstone (JS) after high temperature (25 900 °C) treatment. These tests aimed to analyze their mineral composition, microstructure, tensile mechanical damage, and morphological parameters. The results indicate that as temperature rises, the volume of the rocks generally increases, accompanied by a rise in tensile strength damage, reaching 75.4

In recent years, the consumption of natural resources and the generation of large amounts of waste have seriously threatened the progress of human civilization towards sustainable development. Waste such as non-biodegradable and non-self-degradable waste rubber tires have aroused widespread concern for the ecological environment, and recycling and reusing them in a way that partially replaces concrete aggregates is an effective approach to solving the issue of waste rubber tire accumulation and achieving sustainable development of the construction industry. However, the introduction of rubber particles into concrete has a negative impact on the mechanical behavior of concrete. Notably, reinforcing rubberized concrete with steel fibers is an innovative solution to address its shortcomings. This paper provides a comprehensive review of the sustainability and mechanical properties of steel fiber-reinforced rubberized concrete. Specifically, a comprehensive overview of the main material sources for steel fiber-reinforced rubberized concrete is presented in terms of recyclability of waste rubber tires, the characteristics of rubber particles, and the characteristics of steel fibers. Given the sustainability of steel fiber-reinforced rubberized concrete, cost-benefit analysis and environmental sustainability are widely summarized. Furthermore, the mechanical properties of steel fiber-reinforced rubberized concrete such as strength (compressive, splitting tensile, and flexural strength), toughness (compressive, and flexural toughness), elastic modulus, impact resistance, and fracture characteristics are critically reviewed and discussed. Then, the microscopic behavior of steel fiber-reinforced rubberized concrete is evaluated and analyzed. Eventually, research progress in areas related to steel fiber-reinforced rubberized concrete is suggested and further possible research is proposed based on the critical analysis. This paper can provide information for the production and application of sustainable steel fiber-reinforced rubberized concrete with enhanced mechanical properties.

In recent years, manufactured sand produced from crushed rock has been used as fine aggregate instead of natural sand in construction and industrial fields to minimize the impact of natural sand depletion in nature and society. In this research, the mechanical properties and durability of alkali-activated sustainable mortar using manufactured sand and different sodium silicate (solution) to precursor ratios (SSPR; 0.60, 0.65, 0.70, 0.75, and 0.80) by weight were investigated. Metakaolin and fly ash were used as precursor, sodium silicate (solution) and sodium hydroxide were used as alkali-activator, and manufactured sand made from broken limestone was used to completely replace river sand as fine aggregate to prepare metakaolin/fly ash (MK/FA) alkali-activated sustainable mortar to ensure sustainable development. The compressive, tensile, and flexural strengths, anti-permeability, and crack resistance of MK/FA alkali-activated sustainable mortar were tested. The impact of different SSPRs on the mechanical properties and durability of alkali-activated sustainable mortar was analyzed. Quadratic function fitting models of tensile strength to compressive strength and flexural strength to compressive strength were proposed. Furthermore, the statistical effects of each parameter were explored using analysis of variance and F-test of statistical analysis. The experimental results indicate that the SSPR has a remarkable effect on the mechanical properties and durability of MK/FA alkali-activated sustainable mortar. When the SSPR is in the range of 0.6–0.8, the compressive, tensile, and flexural strength of the alkali-activated sustainable mortar initially increased and then decreased; however, there is an opposite trend in water penetration depth and crack index. MK/FA alkali-activated sustainable mortar exhibits best compressive strength, tensile strength, flexural strength, anti-permeability, and cracking resistance of 40.2 MPa, 3.38 MPa, 4.3 MPa, 41.3 mm, and 245 mm, respectively, at SSPR of 0.7. The experimental findings of this study can provide theoretical guidance for practical engineering of alkali-activated sustainable mortars using manufactured sand.

As the most commonly used construction material for marine buildings, cementitious composites are exposed to a complex environment of coupled action of relative humidity, temperature, and chloride salts erosion, which severely impacts the safety and longevity of marine buildings. The effect of nano-SiO2 dosage on the durability of polyvinyl alcohol fiber-reinforced cementitious composites (PVAF-RCC) for the preparation of marine buildings under the complex environment was investigated in this work. The complex environment with the temperature of 50 degrees C, relative humidity of 100%, and chloride salt concentration of 5% was simulated by the environment chamber. The cementitious composites exposed to the complex environment for 30 d were tested for antipermeability, anti-chloride ion penetration, frost resistance, and chloride salt erosion resistance. Furthermore, the pore characteristics of the cementitious composites and the micromorphology of nano-SiO2, matrix, and fibers were characterized and analyzed by the combination of scanning electron microscope and mercury intrusion porosimetry tests. Results revealed that the durability of cementitious composites improved initially and subsequently decreased with rising the dose of nano-SiO2 under the complex environment. PVAF-RCC consisting of 1.5% nano-SiO2 obtained the best durability. As the nano-SiO2 dosage increased, the total porosity and cumulative porosity of PVAF-RCC decreased first and subsequently increased. Nano-SiO2 refined and improved the pore structure of PVAF-RCC and the interface between matrix and PVA fibers through its filling effect and participation in the hydration reaction to generate C-S-H gels with filling effect to convert more harmful and harmful pores into less harmful or harmless pores, thus enhancing the compactness and durability of cementitious composites under the complex environment.

In recent decades, the need for high-performance and cost-effective concrete has received considerable attention from both researchers and different construction industries due to the ever-growing demand for concrete. Steel fiber reinforced concrete (SFRC) is a popular material for its extremely high strength, high crack control, high fracture toughness, and good cost-effectiveness. This paper provides a thorough review of the fracture properties of SFRC. Specifically, the purpose of this paper is to emphasize the most compelling and feasible fracture toughness and other strength enhancements method for concrete using steel fiber (SF). Furthermore, it comprehensively reviews fracture models of SFRC, double-K fracture model (DKFM), boundary effect model (BEM), fictitious crack model (FCM), effective crack model (ECM), numerical simulation model (NSM), the evaluation parameters for fracture of SFRC, as well as the test methods and techniques used to study fracture properties of SFRC. The effects of SF volume fraction and SF distribution on the fracture properties of SFRC are also presented in the paper. The results show that the fracture properties of SFRC increase significantly with the increase of randomly distributed SF volume fraction from 0 to 1.6%. It has also found that the fracture properties of aligned steel fiber reinforced concrete (ASFRC) are 1.3–1.79 times higher than those of randomly distributed SFRC. Yet, there are still many issues that need to be addressed in the application of SFRC in practical engineering. Hence, scholars and engineers must conduct further research to solve the fracture problems in practical engineering applications.

The existence of joint at key position will change the stress distribution law around the tunnel, thereby changing the strength and stability of the tunnel. Therefore, a series of uniaxial compression tests were performed on the single-holed samples containing a joint to explore the effect of key joint parameters, including joint inclination (0°, 30°, 45°, 60°, and 90°) and length (20, 30, 40, and 50 mm), on the mechanical and fracture characteristics of the tunnel. Meantime, the DIC equipment and box dimension method were used to analyze the surface strain field of the sample and quantitatively characterize the surface crack of the failed sample, respectively. The experimental results show the uniaxial compressive strength of samples reaches the maximum and minimum values at joint inclination angles of 0° and 60°, respectively, and the strength of samples is negatively correlated with the joint length. Interestingly, the existence of some key joints can help to improve the strength of the single-holed sample. The strain bands and cracks mainly develop around the joint and the tunnel, which is well explained by the stress distribution results calculated by COMSOL software. The numerical results show that with the increase of joint inclination, the tensile stress at the upper endpoint of circular hole is increasing, and the compressive stress at left and right endpoints of the hole slightly increases. Analyzing the relative positional relationship between the coalescence path and the tunnel, the failure modes of the sample with different joint inclinations are classified into three types: center-symmetric failure (0° and 90°), through-joint failure (30° and 45°) and axisymmetric failure (60°). Additionally, the box fractal dimension of the surface crack of failed sample at the peak stress is closely related to the failure mode of the sample, and the box fractal dimension of samples with the same failure mode is positively correlated with their peak stress.

Delayed re-endothelialization after coronary drug-eluting stent implantation is associated with an increased incidence of late in-stent thrombosis. Serum exosomes exhibit controversial effects on promoting endothelialization. This study aimed to compare the angiogenic effects of serum exosomes derived from patients with acute myocardial infarction (AMI) and AMI plus diabetes mellitus (DM) and to explore the underlying mechanisms. Serum exosomes derived from patients in the control (Con-Exos), AMI (AMI-Exos), and AMI plus DM (AMI+DM-Exos) groups were isolated and identified using standard assays. CCK-8, wound healing, and tube formation assays were performed to detect the angiogenic abilities of serum exosomes on rapamycin-conditioned human umbilical vein endothelial cells (HUVECs). Differential proteomic profiles between AMI-Exos and AMI+DM-Exos were analyzed by mass spectrometry. The effects and potential mechanisms of exosomal angiopoietin-like 6 (ANGPTL6) were investigated. Functional assays indicated that compared with Con-Exos, AMI-Exos enhanced, whereas AMI+DM-Exos inhibited the cell proliferation, migration, and tube formation of rapamycin-conditioned HUVECs. Subsequently, 28 differentially expressed proteins between AMI-Exos and AMI+DM-Exos were identified, which were correlated with material transportation, immunity, and inflammatory reaction. Moreover, ANGPTL6 was highly enriched in AMI-Exos. Overexpression and knockdown of ANGPTL6 enhanced and inhibited angiogenesis, respectively. Furthermore, the effect of ANGPTL6 on angiogenesis was mediated via the activation of ERK 1/2, JNK, and p38 pathways. The inhibition of ERK 1/2 signaling markedly attenuated the migration abilities of overexpressing ANGPTL6. Diabetes impairs the regenerative capacities of serum exosomes. Exosomal ANGPTL6 contributes to endothelial repair and is a novel therapeutic target for enhanced stent endothelization.

The excellent optical properties of MXene provide new opportunities for short-pulse lasers. A diode-pumped passively Q-switched laser at 1.3 μm wavelength with MXene Ti3C2Tx as saturable absorber was achieved for the first time. The stable passively Q-switched laser has 454 ns pulse width and 162 kHz repetition rate at 4.5 W incident pumped power. The experimental results show that the MXene Ti3C2Tx saturable absorber can be used as an optical modulator to generate short pulse lasers in a solid-state laser field.

AIMS:The meta-analysis was aimed to search for candidate blood markers whose pre-ablation level was associated with atrial fibrillation (AF) recurrence after radiofrequency catheter ablation (RFCA).METHODS AND RESULTS:A systematic literature search of PubMed, EMBASE, Springer Link, Web of Science, Wiley-Cochrane library, and supplemented with Google scholar search engine was performed. Thirty-six studies covering 11 blood markers were qualified for this meta-analysis. Compared with the nonrecurrence group, the recurrence group had increased pre-ablation level of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), N-terminal pro-brain natriuretic peptide (NT-pro-BNP), interleukin-6 (IL-6), C-reactive protein, low density lipoprotein (LDL), and tissue inhibitor of metal loproteinase-2 (TIMP-2) [standardized mean difference (95% confidence interval): 0.37 (0.13-0.61), 0.77 (0.40-1.14), 1.25 (0.64-1.87), 0.37 (0.21-0.52), 0.35 (0.10-0.60), 0.24 (0.07-0.42), 0.17 (0.00-0.34), respectively], while no statistical difference of pre-ablation level of white blood cell, total cholesterol, triglyceride, and transforming growth factor-β1 was found. Subgroup analysis demonstrated that ANP was associated with AF recurrence in participants who had no concomitant structural heart diseases (SHD); however, not in participants who had SHD, C-reactive protein was associated with AF recurrence in Asian studies, whereas not in European studies.CONCLUSION:Increased pre-ablation level of ANP, BNP, NT-pro-BNP, IL-6, C-reactive protein, LDL, and TIMP-2 was associated with greater risk of AF recurrence after RFCA.

Background: Published data indicated that combination use of clopidogrel and proton pump inhibitors (PPIs) may increase the incidence of major adverse cardiovascular events (MACEs). This has been a highly controversial topic for years. Design: The present study was performed to evaluate whether combination therapy of clopidogrel and PPIs is associated with increased risk of MACEs than with clopidogrel alone in patients with coronary artery disease. Methods: A systematic search of MEDLINE, EMBASE, and the Cochrane Library was conducted for studies recording the occurrence of MACEs in patients with exposure to concomitant use of clopidogrel and PPIs up to February 2015. Odds ratios (ORs) were combined using a random-effects model. Results: Patients receiving combination therapy with PPIs and clopidogrel were at significantly increased risk of MACEs (OR: 1.42; 95% confidence interval [CI]: 1.30-1.55). Adding a PPI to clopidogrel treatment was associated with a higher rate of MACE occurrence in rapid metabolizers (RMs, *1/*1) of CYP2C19 (OR: 1.42; 95% CI: 1.12-1.81), but there was no obviously increased rate (OR: 1.43; 95% CI: 0.89-2.28) in decreased metabolizers (with 1 or 2 loss-of-function allele). The increased risk of MACEs was similar in 4 classes of PPIs (omeprazole, lansoprazole, esomeprazole, and pantoprazole), but rabeprazole (OR: 1.03; 95% CI: 0.55-1.95) wasn’t. Conclusion: The combination use of clopidogrel and certain types of PPIs (omeprazole, lansoprazole, esomeprazole, pantoprazole) increases the risk of MACE in patients with coronary artery disease. Only in the RMs of CYP2C19, PPIs were associated with significantly increased MACE in patients coadministered with clopidogrel.