Intelligent colorimetric indicator films were prepared to monitor freshness/spoilage of milk and fish by incorporating purple tomato anthocyanin (PTA) into chitosan (CS) matrix via solution casting ...method with PTA concentration (w/w, based on CS) of 10%, 30%, and 50%, respectively. The pH-response, UV absorption, Swelling Index, and the mechanical properties of CS/PTA films were determined. It was found that the color of the original CS/PTA films became darker with an improvement of PTA content and expressed well pH-sensitivity. With increasing of pH, the color of the CS/PTA films exposed to pH = 3–11 solutions became darker and the change in color of the CS/10% PTA film was the most discernable. The tensile strength and Young's modulus of the CS/PTA film was much lower than that of CS film, however, the elongation at breaking and Swelling Index were both improved by adding PTA. The intelligent films with 10% PTA changed their color during progressive spoilage of milk or fish, revealing their potential application for monitoring food freshness/spoilage.
•Anthocyanins extracted from purple tomatoes were used to develop pH indicator films.•The physichemical properties of films were dependent on the PTA content.•The color change of films with 10% concentration of PTA was the most discernable.•The films containing 10%PTA could monitor freshness/spoilage of milk and fish.
Using elliptical iron glycolate nanosheets as precursors, elliptical Fe3O4/C core–shell nanorings (NRs) 25 ± 10 nm in wall thickness, 150 ± 40 nm in length, and 1.6 ± 0.3 in long/short axis ratio are ...synthesized via a one-pot hydrothermal route. The surface-poly(vinylpyrrolidone) (PVP)-protected-glucose reduction/carbonization/Ostwald ripening mechanism is responsible for Fe3O4/C NR formation. Increasing the glucose/precursor molar ratio can enhance carbon contents, causing a linear decrease in saturation magnetization (M s) and coercivity (H c). The Fe3O4/C NRs reveal enhanced low-frequency microwave absorption because of improvements to their permittivity and impedance matching. A maximum R L value of −55.68 dB at 3.44 GHz is achieved by Fe3O4/C NRs with 11.95 wt % C content at a volume fraction of 17 vol %. Reflection loss (R L) values (≤−20 dB) are observed at 2.11–10.99 and 16.5–17.26 GHz. Our research provides insights into the microwave absorption mechanism of elliptical Fe3O4/C core–shell NRs. Findings indicate that ring-like and core–shell nanostructures are promising structures for devising new and effective microwave absorbers.
The molecular mechanisms underlying the development of ischemic cardiomyopathy (ICM) remain poorly understood. Gene expression profiling is helpful to discover the molecular changes taking place in ...ICM. The aim of this study was to identify the genes that are significantly changed during the development of heart failure caused by ICM. The differentially expressed genes (DEGs) were identified from 162 control samples and 227 ICM patients. PANTHER was used to perform gene ontology (GO), and Reactome for pathway enrichment analysis. A protein-protein interaction network was established using STRING and Cytoscape. A further validation was performed by real-time polymerase chain reaction (RT-PCR). A total of 255 common DEGs was found. Gene ontology, pathway enrichment, and protein-protein interaction analysis showed that nucleic acid-binding proteins, enzymes, and transcription factors accounted for a great part of the DEGs, while immune system signaling and cytokine signaling displayed the most significant changes. Furthermore, seven hub genes and nine transcription factors were identified. Interestingly, the top five upregulated DEGs were located on chromosome Y, and four of the top five downregulated DEGs were involved in immune and inflammation signaling. Further, the top DEGs were validated by RT-PCR in human samples. Our study explored the possible molecular mechanisms of heart failure caused by ischemic heart disease.
High-quality elliptical polycrystalline Fe3O4 nanorings (NRs) with continuously tunable size have been synthesized in large amounts via a rapid microwave-assisted hydrothermal approach. The ...surface-protected glucose reducing/etching/Ostwald ripening mechanism is responsible for the formation of NRs. Ring size can be modulated by selecting iron glycolate nanosheets with various sizes as precursors. The size-dependent magnetic behavior of the NRs was observed. Our research gives insights into the understanding of the microwave absorption mechanism of elliptical Fe3O4 NRs. Owing to their large specific surface area, shape anisotropy, and closed ring-like configuration, elliptical polycrystalline Fe3O4 NRs exhibited significantly enhanced microwave absorption performance compared with Fe3O4 circular NRs, nanosheets, microspheres, nanospindles, and nanotubes. An optimal reflection loss value of −41.59 dB is achieved at 5.84 GHz and RL values (≤−20 dB) are observed at 3.2-10.4 GHz. Some new mechanisms including multiple scattering, oscillation resonance absorption, microantenna radiation, and interference are also crucial to the enhanced absorption properties of NRs. These findings indicate that ring-like nanostructures are a promising structure for devising new and effective microwave absorbers.
In organic-inorganic hybrid perovskite solar cells, though the current density-voltage (J-V) hysteresis phenomenon is accepted to be caused by ion migration coupled with charge carrier recombination, ...there are still rich hysteresis characteristics (various J-V hysteresis loops) remaining to be explained. Here, a systematic drift-diffusion simulation study is conducted to explore the effect of interfacial recombination lifetime (τinterface), bulk charge carrier lifetime (τbulk) and mobility (μ) on J-V hysteresis behaviors. The simulation results show that, for devices with only interfacial recombination, the decrease of τinterface will lead to J-V hysteresis loops with a large gap on the open circuit side. For devices with only bulk recombination, the drop of τbulk will lead to J-V hysteresis loops with a large gap on the short circuit side. Meanwhile, in both cases, the decrease of μ aggravates the effect of interfacial and bulk recombination, while it has no effect on VOC. Our simulations reveal the effect of decreased τinterface, τbulk and μ on the J-V characteristics and explain the hysteresis loops with specific shapes, which have been reported in the literature.
Abstract
The EMU roof with a thin plate structure is prone to buckling deformation during welding, which will affect its stability. Due to the complex structure, large size, and many types of welded ...joints, it is an urgent problem to solve the influence of different joint shapes on welding deformation and buckling stability in one model. Based on the inherent strain-temperature loading method, the inherent strain data of four kinds of local joint butt, lap, fillet, and plug welding were accurately obtained through joint welding deformation verification. Then the welding deformation simulation and buckling stability analysis were conducted. The results indicate that plug welding will have minimal impact on roof deformation. The roof buckling deformation cannot occur under the original and 1.2 times heat input conditions are selected within the range of the actual given heat source parameters. Under the 1.5 times heat input condition, the roof buckling deformation occurs. The results provide technical support for the selection of the welding process and the roof stability study of the EMU.
Bioactive-packaging films based on polylactic acid (PLA), acetyl tributyl citrate (ATBC), and tea polyphenol (TP) were prepared by melt blending. Results of mechanical-property test revealed that ...adding ATBC and TP can significantly improve mechanical properties of PLA. The shift of CO to lower wavelengths in FTIR and the morphology of the films in SEM indicated physical or chemical interactions in the PLA/ATBC/TP films. The antioxidant, and antibacterial activities of the PLA/ATBC films increased dramatically (P<0.05) with increased TP amount. The antioxidant activity of the films with 1 % TP was equivalent to that of 300 mg/L l-ascorbic acid, whereas PLA/ATBC/TP films with 0.5 % and 1 % TP concentration were effective in inhibiting Staphylococcus aureus and Escherichia coli within almost 5 h (P<0.05). The PLA films changed from transparent to opaque and from yellow to red after combining with ATBC or TP, respectively. The overall migration of the films in 3 % acetic acid and 10 % ethanol did not exceed the overall migration limit. All these findings indicated potential of the PLA/ATBC/TP films in active-packaging application.
•Bioactive-packaging films based on PLA, ATBC, and tea polyphenol (TP) were prepared.•The addition of ATBC and TP can significantly improve the mechanical properties of PLA.•The antioxidant, and antibacterial activities of the PLA/ATBC films increased with increased TP amount.•The overall migration of the films in food simulants meets well EU NO 10/2011 as packaging materials.
•Surface tension between PLA/CS blend solution and PLA film modified by MDI.•Better wettability between PLA/CS blend solution and PLA film by increasing MDI.•Increased breaking strength by increasing ...MDI due to the increased H-bonding.•Increased number of physical entanglements between PLA/CS coating and PLA film.•Development of a suitable bio-based multilayer film for food packaging applications.
The objective of this study was to investigate the effect of methyldiphenyl diisocyanate (MDI) concentration (0, 0.2, 1, 2, and 3%) on the wettability and adhesion of blend solutions of poly(lactic acid) (PLA) and chitosan (CS) when coated on PLA film for development of a bio-based multi-layer film suitable for food packaging and other applications. Characterization was carried out by attenuated total reflectance infrared spectrometry (ATR-FTIR), contact angle (θ), mechanical adhesion pull-off testing, and scanning electron microscopy (SEM). The θ of the PLA/CS blend shifted to a lower value (41–35°) with increasing MDI concentration showing that the surface tension was modified between the PLA/CS blend solution and PLA film and better wettability was achieved. The increase in MDI also resulted in an increased breaking strength (228–303kPa) due to the increased H-bonding resulting from the more urethane groups formed within the PLA/CS blend as shown by ATR-FTIR. The improved adhesion was also shown by the increased number of physical entanglements observed by SEM. It can be concluded that MDI can be used to improve wettability and adhesion between PLA/CS coating and PLA film.
The strength of the mounting seat under static strength conditions determines the stability and reliability of the energy-absorbing structure on the metro vehicle. In this paper, five improvement ...schemes were proposed and the optimal scheme was determined under the worst static strength load condition for the mounting seat of energy-absorbing structure. The results showed that reinforcements had no obvious effect on the stress distribution at the weld seam of the mounting seat. According to the characteristic of transferring deformation and force, the effect of changing the position of the weld seam and moving it away from the stress concentration area was more feasible method.
Objective The aim of the study was to investigate whether ethanolic extract of propolis inhibits the growth and induces apoptosis of HL-60 cel s. Methods HL-60 cel s were treated for 24, 48, 72 h ...with various concentrations ethanolic extracts of prop-olis （0, 50, 100, and 200 μg/mL）. The proliferation of HL-60 cels was determined using the 3-（4,5-dimeth-ylthiazol-2-yl）-2,5-diphenyltetrazolium bromide （MTT） assay. Subsequently, Hochest 33258 staining and terminal deoxynucleotidyl transferase dUTP nick end labeling （TUNEL） were used to test the apoptosis of HL-60 cel s. We observed the expression levels of Bax and Bcl-2 in HL-60 cel s by immunohistochemistry. Results MTT assay showed that various concentrations of ethanolic extract of propolis had significant inhibitory efect on HL-60 cel proliferation （P〈 0.05）. Typical morphologic changes could be observed by fluorescence microscope and TUNEL. By immunohistochemistry, we found the expression level of Bax was up-regulated, whereas that of Bc1-2 was down-regulated （P 〈 0.05）.Conclusion Ethanolic extract of propolis inhibits leukemia cel proliferation and induces apoptosis in vitro. Its mechanism may be related to the regulation of Bax and Bcl-2 expression and up-regulation of Bcl-2/Bax ratio.
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