Recently, functional applications of thermoplastic foams have received extensive attention from the research and materials communities, focusing on their various applications, key challenges, ...material systems designs, processing methods, and cellular structure characteristics needed for specific functional applications. This review paper starts with consideration of the microcellular foaming mechanism and basic concepts of microcellular foam processing, followed by polymer modification methods, and crucial factors that determine the performance of thermoplastic foams. Special emphasis has been placed on the synergies between foaming and reinforcements, including functional fillers and polymer blends; improvements in homogeneous, functional properties by achieving uniform cell structure and cell dispersion in polymer systems; and comparison of melt processing and solvent-based methods. Then, a wide array of advanced functional applications for foams—such as lightweight applications, heat and sound insulation, electromagnetic shielding, tissue engineering, oil spill cleanup, shape memory, and flexible materials—will be presented. In particular, the relationships between cellular structure and anticipated properties—including mechanical, barrier, dielectric, biomedical, and other properties required in advanced functional applications—will be discussed. Finally, we will outline a future perspective of lightweight and functional foams and suggest recommended future work regarding functional microcellular foams.
We and others have demonstrated that anthocyanins have antiatherogenic capability. Because intact anthocyanins are absorbed very poorly, the low level of circulating parent anthocyanins may not fully ...account for their beneficial effect. We found recently that protocatechuic acid (PCA), a metabolite of cyanidin-3 to 0-β-glucoside (Cy-3-G), has a remarkable antiatherogenic effect.
To investigate whether mouse gut microbiota metabolizes Cy-3-G into PCA and to determine whether and how PCA contributes to the antiatherogenic potency of its precursor, Cy-3-G.
PCA was determined as a gut microbiota metabolite of Cy-3-G in ApoE(-/-) mice, verified by the utilization of antibiotics to eliminate gut microbiota and further microbiota acquisition. PCA but not Cy-3-G at physiologically reachable concentrations promoted cholesterol efflux from macrophages and macrophage ABCA1 and ABCG1 expression. By conducting a miRNA microarray screening, we revealed that expression of miRNA-10b in macrophages can be reduced by PCA. Functional analyses demonstrated that miRNA-10b directly represses ABCA1 and ABCG1 and negatively regulates cholesterol efflux from murine- and human-derived macrophages. Further in vitro and ex vivo analyses verified that PCA accelerates macrophage cholesterol efflux, correlating with the regulation of miRNA-10b-ABCA1/ABCG1 cascade, whereas Cy-3-G consumption promoted macrophage RCT and regressed atherosclerotic lesion in a gut microbiotaendependent manner.
PCA, as the gut microbiota metabolite of Cy-3-G, exerts the antiatherogenic effect partially through this newly defined miRNA-10b-ABCA1/ABCG1-cholesterol efflux signaling cascade. Thus, gut microbiota is a potential novel target for atherosclerosis prevention and treatment.
To investigate the degradation law of the mechanical properties of corroded steel, the standard specimens from machining steel members in service for 9 years in an industrial environment were ...subjected to tensile tests. The influences of different degrees and types of corrosion on the fracture path, stress-strain curve, and mechanical properties of specimens were discussed. Finally, the damage constitutive model of corroded steel was established based on the damage mechanics theory. The results showed that the failure modes of corroded specimens were related to the degrees and types of corrosion. The fracture morphology of specimens with general corrosion were step-like and the fractures of steel were uneven. However, those with local corrosion were mainly flat-like, and the fracture path was along the cross section where the larger corrosion pits were located. The fracture path of the specimen was related to the interaction of the corroded surface and internal material defects (holes). Meanwhile, with the increase of corrosion degree, the yield platform of stress-strain curve gradually became shorter, or even disappeared, and the ultimate strain and elongation at break decreased, implying that the ductility of steel became worse. Ultimately, the good agreement between the curves of the model and test indicated that the damage model could reflect the damage development process of corroded steel in the tensile process better. Corrosion damage resulted in the decrease in the damage threshold, and the damage variable
decreased by the time fracture occurred and the maximum reduction rate was up to 62.5%.
The nanocomposites of flower-like nickel phyllosilicate particles incorporated into epoxy resin were fabricated via an
in-situ
mixing process. The flower-like nickel phyllosilicate particles were ...firstly synthesized using a mild self-sacrificial templating method, and the morphology and lamellar structure were examined carefully. Several properties of mechanical, thermal and tribological responses of epoxy nanocomposites were performed. It was demonstrated that adequate flower-like nickel phyllosilicate particles dispersed well in the matrix, and the nanocomposites displayed enhanced tensile strength and elastic modulus but decreased elongation at break as expected. In addition, friction coefficient and wear rate were increased first and then decreased along with the particle content, and showed the lowest values at a mass fraction of 5%. Nevertheless, the incorporated flower-like nickel phyllosilicate particles resulted in the continuously increasing thermal stability of epoxy resin (EP) nanocomposites. This study revealed the giant potential of flower-like particles in preparing high-quality EP nanocomposites.
Poor interfacial adhesion and dispersity severely obstruct the continued development of carbon nanotube (CNT)-reinforced epoxy (EP) for potential applications. Herein, hierarchical CNT nanohybrids ...using nickel phyllosilicate (Ni-PS) as surface decorations (CNT@Ni-PS) were synthesized, and the nanocomposites derived from varied mass fractions of EP and CNT@Ni-PS were prepared. The morphological structures, tribological performances, curing behaviors and thermal properties of EP/CNT@Ni-PS nanocomposites were carefully investigated. Results show that hierarchical CNT nanohybrids with homogeneous dispersion and well-bonded interfacial adhesion in the matrix are successfully obtained, presenting significantly improved thermal and tribological properties. Moreover, analysis on cure kinetics proves the excellent promotion of CNT@Ni-PS on the non-isothermal curing process, lowering the curing energy barrier steadily.
Raising attentions have focused on how to alleviate greenhouse gas (GHG) emissions from orchard system while simultaneously increase fruit production. Microalgae-based biofertilizer represents a ...promising resource for improving soil fertility and higher productivity. However, the effects of microalgae application more especially live microalgae on GHG emissions are understudied. In this study, fruit yield and quality, GHG emissions, as well as soil organic carbon and nitrogen fractions were examined in a hawthorn orchard, under the effects of live microalgae-based biofertilizer applied at three doses and two modes. Compared with conventional fertilization, microalgae improved hawthorn yield by 15.7%−29.6% with a maximal increment at medium dose by root application, and significantly increased soluble and reducing sugars contents at high dose. While microalgae did not increase GHG emissions except for nitrous oxide at high dose by root application, instead it significantly increased methane uptake by 1.5−2.3 times in root application. In addition, microalgae showed an increasing trend in soil organic carbon content, and significantly increased the contents of soil dissolved organic carbon and microbial biomass carbon, as well as soil ammonium nitrogen and dissolved organic nitrogen at medium dose with root application. Overall, the results indicated that the live microalgae could be used as a green biofertilizer for improving fruit yield without increasing GHG emissions intensity and the comprehensive greenhouse effect, in particular at medium dose with root application. We presume that if lowering chemical fertilizer rates, application of the live microalgae-based biofertilizer may help to reduce nitrous oxide emissions without compromising fruit yield and quality.
A novel low-alloy ultrahigh-strength steel featuring excellent mechanical properties and comprising a nanolath structure was fabricated in this work using a quenching-partitioning-tempering (Q-P-T) ...process. The Q-P-T process comprised direct quenching and an isothermal bainitic transformation for partitioning after thermo-mechanical control processing (online Q&P) and offline tempering (reheating and tempering). The ultrafine nanolath martensite/bainite mixed structure, combined with residual austenite in the form of a thin film between the nanolaths, was formed, thereby conferring excellent mechanical properties to the steel structures. After the Q-P-T process, the yield and tensile strengths of the steels reached 1450 MPa and 1726 MPa, respectively. Furthermore, the Brinell hardness and elongation rate were 543 HB and 11.5%, respectively, with an average impact energy of 20 J at room temperature.
The immunosuppressants monitoring is crucial in the treatment of transplant patients to avoid the risk of organ rejection. So it is vital to develop an accurate method to obtain precise and reliable ...results. Herein, a liquid chromatography tandem mass spectrometry (LC–MS/MS) based method was developed and validated, which could simultaneously realize the accurate quantification of cyclosporine A and tacrolimus with a total run time of 4.5 min. Unlike the previously described methods, the highlight of this assay is that there is no using zinc sulfate in the protein precipitation of the whole blood sample, which can effectively prolong the lifespan of mass spectrometry. In addition, the linearity, matrix effect, carryover, accuracy, intraday and interday precision of this method were investigated. The linear range of tacrolimus and cyclosporine were 1–40 ng/mL and 50–2000 ng/mL, respectively; The correlation coefficients (
R
2
) were both greater than 0.995. The intraday and interday precision of cyclosporine and tacrolimus were ≤ 10%. The lower limit of quantitation (LLOQ) of tacrolimus and cyclosporine A were 1 ng/mL and 50 ng/mL, respectively. The main features of this method are good accuracy, sensitivity, specificity, rapidness, robustness and high throughput. It is suitable for therapeutic drug monitoring of cyclosporine A and tacrolimus in routine clinical diagnostics.
The act of land transfer in rural areas is an important decision-making mechanism for farmers, to enhance resource allocation efficiency and promote capital mobility, and this act is of strategic ...importance in promoting the level of agricultural scale and mechanization, land system change, and, thus, the sustainable development of livelihoods and production in China. This study aims to explore farmers’ decision-making mechanisms in the process of land transfer in rural areas, by constructing a theoretical framework. Structural equation modeling was used, based on data from a survey of rural families in the Liaoning Province area of Northeastern China. The main findings are as follows: (1) The seven types of exogenous latent variables, including environmental vulnerability, policy, and five main livelihood assets (natural capital, physical capital, financial capital, human capital, and social capital), are intermediary in farmers’ land transfer behavior, which then positively affect farmers’ livelihood outcomes. (2) Among the exogenous latent variables affecting farmers’ land transfer, human assets have the most significant positive effect, followed by social assets and physical assets, family labor force share, frequency of work information exchange, and number of production tools, greatly affect the corresponding variable. (3) Natural assets play the most important role and have a negative effect on farmers’ land transfer decision; contracted area of land per family is the greatest impacted measurable variable of this. The results of the study suggest that the government should strengthen skills training for farmers, improve the land transfer policy system, and provide appropriate subsidies in a regionally targeted manner. Thus, it can promote the transformation of Chinese-style agricultural modernization and achieve rural revitalization.
Regulating farmers’ choice of agricultural production service (APS) contracts can help maintain the stability of transactions, enhance agricultural production efficiency, protect farmers’ rights and ...welfare, stimulate the healthy and sustainable development of service organizations, and promote the economic benefits of agriculture. Under the uncertainty of risk (RU), farmers’ willingness to sign a regulated service contract after purchasing APS is a key factor in reaching an efficient and high-quality partnership. Based on the survey data of the black soil area in northeastern China, this study uses the Heckman two-stage model and analyzes it under the logical framework of APS purchases and contractual choice behavior (CCB) under the role of RU. The main findings are as follows. First, the RU has a significant “inducing” effect on farmers’ CCB, and the higher the RU, the more farmers tend to make formal written contracts; among them, each unit increase in business risk increases farmers’ choice of written contracts by 0.797 units, which is an important factor affecting CCB. Second, farmers’ personal trust level played a positive moderating role in influencing CCB. Compared to the low trust level group, farmers in the high trust level group had a diminished degree of influence on CCB, but the intensity was relatively weak. Third, farmers’ personal, family, and social characteristics all influence their behavioral decision-making processes. In order to reduce the risk level of cooperation between farmers and service providers, which can promote the standardization of cooperation contracts, this study suggests that the government should use the publication of manuals and other forms to carry out legal literacy, promote labor market information transparency, reduce service risks, and enhance the effectiveness of the linkage between farmers and service providers.
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