•An innovative CFRP textile-reinforced ECC (TRE) system was proposed for repairing fire-damaged RC columns.•The effects of different design parameters on the axial compressive behavior of the columns ...were investigated and compared.•The TRE system was found to enhance the load capacity, secant stiffness and ultimate displacement of fire-damaged RC columns.•The typical failure mode of the strengthened specimens was attributed to the tensile rupture of the fibers in the TRE jacket.
Fiber-reinforced polymer (FRP) textile reinforced engineered cementitious composite (ECC) matrix (TRE for short) is a newly developed composite system with great potential for the strengthening and life extension of damaged reinforced concrete (RC) columns after fire exposure. It combines the advantages of the lightweight and high strength of FRP textile and the ultra-high ductility of ECC material. However, there is a lack of research on the use of the TRE system to strengthen fire-damaged RC columns. This paper presents an experimental study on the axial compressive behavior of fire-damaged square RC columns strengthened with the TRE system. A total of 13 specimens were prepared and tested under axial compression. The test variables included the fire-exposure time (2 h or 3 h) used to produce the initial pre-damage of RC columns, the type of cementitious matrix (ECC or mortar), the number of TRE layers (2 layers or 3 layers), and the thickness of the concrete cover (20 mm or 40 mm). The failure modes, load capacity, secant stiffness, ultimate displacement, load–displacement curves of the specimens and the hoop tensile strains in the outermost layer of the CFRP textiles were investigated and discussed. The typical failure mode of the strengthened specimens was characterized by tensile rupture of the fiber rovings bridging the main crack in the strengthening jacket. The results showed that the use of the TRE system could significantly increase the load capacity, secant stiffness and ultimate displacement of fire-damaged RC columns. Depending on the design parameters, the enhancement percentages in the load capacity varied between 18% and 126%.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Traditional treatment of cotton fabrics by multifunctional nanoparticles usually exhibits easy aggregation and poor durability. Here, we utilize dopamine as a bio-based binder for cotton and one of ...organic ligands to construct highly uniform dispersion of monodispersed zeolitic imidazolate framework-8 (ZIF-8) on the surface of cotton fibers (PZIF-8@Cotton) via in-situ coprecipitation technology at a mild synthesizing process. The resulting PZIF-8@Cotton displays evidently fire safety, especially, 77.9% smoke production is suppressed at 4 wt% of PZIF-8 coating loading. More importantly, owing to the advanced pore feature of PZIF-8 and interfacial force between PZIF-8 and cotton, PZIF-8@Cotton presents excellent durability. After 50 times of washing, the Zn content of PZIF-8@Cotton is rarely reduced (from 1.28 to 1.21%), and the antibacterial properties of
Staphylococcus aureus
and
Escherichia coli
still reach to 99.99% and 98.24%, respectively. Moreover, the multifunctional treatment does not deteriorate the mechanical performance of cotton. While the UV resistance is largely enhanced, and the comfort of the PZIF-8@Cotton is well maintained due to the little change in the hydrophilicity and air permeability. This extremely simple method provides an ideal strategy to obtain multifunctional and durable cotton fabrics.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
This study aimed to investigate the preventive effects of lactoferrin (Lf) on chronic alcoholic liver injury (ALI) in female mice. Female C57BL/6J mice were randomly divided into four groups: control ...group (CON), ethanol administration group (EtOH), low-dose Lf treatment group (LLf), and high-dose Lf group (HLf). In the last three groups, chronic ALI was induced by administering 20% ethanol ad libitum for 12 weeks. Mice in the CON and EtOH groups were fed with AIN-93G diet. Meanwhile, 0.4% and 4% casein in the AIN-93G diet were replaced by Lf as the diets of LLf and HLf groups, respectively. HLf significantly reduced hepatic triglyceride content and improved pathological morphology. HLf could inhibit cytochrome P450 2E1 overexpression and promote alcohol dehydrogenase-1 expression. HLf activated protein kinase B and AMP-activated protein kinase (AMPK), as well as upregulating nuclear-factor-erythroid-2-related factor-2 expression to elevate hepatic antioxidative enzyme activities. AMPK activation also benefited hepatic lipid metabolism. Meanwhile, HLf had no obvious beneficial effects on gut microbiota. In summary, Lf could alleviate chronic ALI in female mice, which was associated with redox balance and lipid metabolism regulation.
•An analytical model was proposed to study post-fire bond behavior of corroded steel bars in concrete.•Combined actions of loading and volume expansion of corrosion products were properly considered ...in the theoretical analysis.•Residual bond strengths of corroded steel bars could be accurately predicted by the proposed analytical model.•Slight corrosion levels of steel bars could delay the bond strength degradations caused by high temperature exposure.
Reinforced concrete structures used in aggressive environments (e.g., coastal and ocean regions) may suffer from steel corrosion. On the other hand, structures with corroded steel bars are likely to experience fire hazards during their service life. Therefore, the combined effect of high-temperature exposure and steel corrosion may lead to a significant reduction in the post-fire bond strength between the corroded steel bars and surrounding concrete, which will further affect the residual load-capacity assessment of fire-damaged RC members. This paper presents an analytical model for predicting the residual bond strengths between the corroded steel bars and surrounding concrete after exposure to high temperatures. In the analytical model, the concrete cover around the steel bar is considered as a thick-walled cylinder whose inner surface is subjected to uniform pressure due to the combined action of the pull-out load and the volume expansion of the corrosion products. Three stages of the concrete cover (i.e., uncracked, partially cracked and fully cracked stages) are considered one by one in the analytical model to determine the internal pressure. During the analysis, the tensile softening behavior of the cracked concrete and the material property degradations of concrete after high-temperature exposure are properly considered. The accuracy and reliability of the proposed analytical model are verified by comparing the analytical predictions with the corresponding pull-out test results collected from the literature. A detailed parametric analysis is then performed to gain insight into the effects of various factors on the post-fire residual bond strengths of corroded steel bars.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In the presence of chiral phosphoramidite ligand, a palladium-catalyzed asymmetric allylic C–H alkylation of 1,4-dienes with cyclic β-keto esters has been established to afford chiral ...α,α-disubstituted β-keto esters in good to excellent yields, with high levels of regioselectivity, E/Z selectivity, and enantioselectivity. 1,4-Dienes bearing a wide scope of functional groups, such as ketone, chloride, ester, and amide as well, have been nicely tolerated. In addition, preliminary application of this method enables a concise formal synthesis of (−)-tanikolide.
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IJS, KILJ, NUK, PNG, UL, UM
Lysine-specific demethylase 5B (KDM5B) has been recognized as a potential drug target for cardiovascular diseases. In this work, we first found that the KDM5B level was increased in mouse hearts ...after transverse aortic constriction (TAC) and in Ang II-induced activated cardiac fibroblasts. Structure-based design and further optimizations led to the discovery of highly potent pyrazole-based KDM5B inhibitor TK-129 (IC50 = 0.044 μM). TK-129 reduced Ang II-induced activation of cardiac fibroblasts in vitro, exhibited good PK profile (F = 42.37%), and reduced isoprenaline-induced myocardial remodeling and fibrosis in vivo. Mechanistically, we found that KDM5B up-regulation in cardiac fibroblast activation was associated with the activation of Wnt-related pathway. The protective effects of TK-129 were associated with its KDM5B inhibition and blocking KDM5B-related Wnt pathway activation. Taken together, TK-129 may represent a novel KDM5-targeting lead compound for cardiac remodeling and fibrosis.
Addressing highly flammable and easily breeding bacteria property via environmentally friendly approach was critical for the large-scale application of lyocell fibers. Herein, a bio-based coating ...constructed by layer-by-layer deposition of adenosine triphosphate (ATP), chitosan (CS), and polyethyleneimine (PEI) was successfully fabricated to obtain excellent fire-resistant and antimicrobial lyocell fabrics (LBL/Lyocell). The resulted fabrics with add-on of 11.5 wt% achieved the limiting oxygen index (LOI) of 32.0 %. Meanwhile, compared with the pure lyocell fabrics, the peak of heat release rate (PHRR), total heat release (THR), and fire growth rate (FIGRA) of LBL/Lyocell fabrics decreased by 75.2 %, 61.0 % and 69.8 % in cone calorimetric test (CCT), respectively. By characterizing the gaseous products and solid residues, the presence of the ATP/CS/PEI coating could not only quickly form the dense expanded carbon layer by itself, but also promote the conversion of cellulose into thermal-stability residues, thus reducing the release of combustible substances during combustion and protecting the lyocell fabrics. In addition, LBL/Lyocell showed excellent antimicrobial properties with 99.99 % antibacterial rates against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). This bio-based coating was a promising candidate for efficiently flame-retardant cellulose fibers with excellent antibacteria.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
A palladium-catalyzed, enantioselective allylic C-H alkylation of 1,4-pentadienes with 5 H-thiazol-4-ones has been developed. Under the cooperative catalysis of a palladium complex of chiral ...phosphoramidite ligand and an achiral Brønsted acid, a broad range of substituted 5 H-thiazol-4-ones bearing sulfur-containing tertiary chiral centers were accessed from the allylic C-H alkylation in high levels of yields and enantioselectivities. Alkyl and aryl 1,4-pentadienes led to linear and branched allylation products, respectively.
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IJS, KILJ, NUK, PNG, UL, UM
Abstract
Context
A high amount of red meat consumption has been associated with higher risks of coronary heart disease (CHD) and all-cause mortality in a single food-exposure model. However, this ...model may overlook the potentially differential influence of red meat on these outcomes depending on the foods replaced by red meat.
Objective
A PRISMA-compliant meta-analysis of prospective observational studies was performed to quantify the risks of CHD and all-cause mortality associated with the replacement of total, unprocessed, or processed red meat with fish/seafood, poultry, dairy, eggs, nuts, and legumes.
Data sources
The PubMed and Web of Science databases were searched to identify relevant articles published in any language from database inception to October 30, 2021.
Data extraction
The prospective observational studies were considered relevant if they reported relative risks (RRs) and 95%CIs for the associations of interest.
Data analysis
Thirteen articles were included. A random-effects model was used to estimate the summary RRs and 95%CIs for the associations of interest. Replacing total red meat with poultry (RR, 0.88, 95%CI, 0.82–0.96; I2 = 0%), dairy (RR, 0.90, 95%CI, 0.88–0.92; I2 = 0%), eggs (RR, 0.86, 95%CI, 0.79–0.94; I2 = 7.1%), nuts (RR, 0.84, 95%CI, 0.74–0.95; I2 = 66.8%), or legumes (RR, 0.84, 95%CI, 0.74–0.95; I2 = 7.3%) was associated with a lower risk of CHD, whereas substituting fish/seafood (RR, 0.91, 95%CI, 0.79–1.04; I2 = 69.5%) for total red meat was not associated with the risk of CHD. The replacement of total red meat with fish/seafood (RR, 0.92, 95%CI, 0.89–0.96; I2 = 86.9%), poultry (RR, 0.92, 95%CI, 0.90–0.95; I2 = 61.6%), eggs (RR, 0.91, 95%CI, 0.87–0.95; I2 = 33.8%), or nuts (RR, 0.92, 95%CI, 0.87–0.97; I2 = 81.9%) was associated with a lower risk of all-cause mortality, whereas the substitution of dairy (RR, 0.97, 95%CI, 0.93–1.01; I2 = 33.9%) or legumes (RR, 0.97, 95%CI, 0.93–1.01; I2 = 53.5%) for total red meat was not associated with the risk of all-cause mortality. Lower risks of CHD and all-cause mortality were more consistently observed for processed red meat replacements than for unprocessed red meat replacements. The results did not materially change when the analyses of total, processed, and unprocessed red meat were restricted to the studies that used a uniform substitution amount per unit of 1 serving/d.
Conclusion
Keeping red meat, particularly processed red meat, consumption to a minimum along with increasing healthier alternative protein sources to replace red meat in the diet may contribute to the prevention of CHD and premature death.
Systematic review registration
PROSPERO registration no. CRD42021259446.
•An analytical model is proposed to investigate the post-fire bond behavior between steel bars and concrete.•Residual bond strengths of steel bars can be accurately predicted by the proposed ...analytical model.•A temperature-dependent local bond-slip model is developed and verified through the comparisons between numerical and experimental results.
Bond behavior between steel bars and concrete is likely to be significantly degraded after exposure to high temperatures in a fire, which will influence the residual strength of the reinforced concrete (RC) member and the selection of appropriate repair and strengthening solutions. This paper presents an analytical model for predicting the bond behavior between steel bars and concrete after exposure to high temperatures. The concrete cover around the steel bar is considered as a thick-walled cylinder whose inner surface is subjected to uniform pressure. The cylinder is further divided into a partially cracked interior portion and an uncracked outer portion under a pull-out loading. The tensile softening behavior of the cracked interior portion and the material property degradations of steel and concrete after exposure to high temperatures are considered. The proposed model has demonstrated its accuracy and reliability in predicting the residual bond strengths of steel bars by comparing the analytical predictions with pull-out tests results from the literature. A local bond-slip relationship is then established and used in a finite element analysis. The finite element results are then compared with measured load–displacement curves that were obtained from pull-out tests in the literature, providing a verification to the proposed bond-slip constitutive law.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
