13 research outputs found

    Seismic Liquefaction Resistance Based on Strain Energy Concept Considering Fine Content Value Effect and Performance Parametric Sensitivity Analysis

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    Liquefaction is one of the most destructive phenomena caused by earthquakes, which has been studied in the issues of potential, triggering and hazard analysis. The strain energy approach is a common method to investigate liquefaction potential. In this study, two Artificial Neural Network (ANN) models were developed to estimate the liquefaction resistance of sandy soil based on the capacity strain energy concept (W) by using laboratory test data. A large database was collected from the literature. One group of the dataset was utilized for validating the process in order to prevent overtraining the presented model. To investigate the complex influence of fine content (FC) on liquefaction resistance, according to previous studies, the second database was arranged by samples with FC of less than 28% and was used to train the second ANN model. Then, two presented ANN models in this study, in addition to four extra available models, were applied to an additional 20 new samples for comparing their results to show the capability and accuracy of the presented models herein. Furthermore, a parametric sensitivity analysis was performed through Monte Carlo Simulation (MCS) to evaluate the effects of parameters and their uncertainties on the liquefaction resistance of soils. According to the results, the developed models provide a higher accuracy prediction performance than the previously publishedmodels. The sensitivity analysis illustrated that the uncertainties of grading parameters significantly affect the liquefaction resistance of soils

    Numerical Modeling of Mantle Flow Beneath Madagascar to Constrain Upper Mantle Rheology Beneath Continental Regions

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    Over the past few decades, azimuthal seismic anisotropy measurements have been widely used proxy to study past and present-day deformation of the lithosphere and to characterize convection in the mantle. Beneath continental regions, distinguishing between shallow and deep sources of anisotropy remains difficult due to poor depth constraints of measurements and a lack of regional-scale geodynamic modeling. Here, we constrain the sources of seismic anisotropy beneath Madagascar where a complex pattern cannot be explained by a single process such as absolute plate motion, global mantle flow, or geology. We test the hypotheses that either Edge-Driven Convection (EDC) or mantle flow derived from mantle wind interactions with lithospheric topography is the dominant source of anisotropy beneath Madagascar. We, therefore, simulate two sets of mantle convection models using regional-scale 3-D computational modeling. We then calculate Lattice Preferred Orientation that develops along pathlines of the mantle flow models and use them to calculate synthetic splitting parameters. Comparison of predicted with observed seismic anisotropy shows a good fit in northern and southern Madagascar for the EDC model, but the mantle wind case only fits well in northern Madagascar. This result suggests the dominant control of the measured anisotropy may be from EDC, but the role of localized fossil anisotropy in narrow shear zones cannot be ruled out in southern Madagascar. Our results suggest that the asthenosphere beneath northern and southern Madagascar is dominated by dislocation creep. Dislocation creep rheology may be dominant in the upper asthenosphere beneath other regions of continental lithosphere

    Natural bioactive peptides to beat exercise-induced fatigue: A review

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    Exercise-induced fatigue is charactered by the feeling of tiredness and a decrease in muscle performance resulting from intense and prolonged exercise. With the development of modern society, exercise-induced fatigue has become a widespread problem besetting people's daily life. Over the years, increasing attention has been paid to the study of anti-fatigue peptides. Several animal models have been developed to mimic exercise-induced fatigue, which could be employed to measure the activities of anti-fatigue peptides isolated from a wide range of sources. A number of natural bioactive peptides were identified with ability to prevent and alleviate exercise-induced fatigue via various complex biological reactions, with possible molecular mechanisms being also explored extensively. In this review, we summarize the major research findings on anti-fatigue peptides, including the isolation and preparation of anti-fatigue peptides, the widely adopted methods for evaluation of anti-fatigue activities, and possible anti-fatigue mechanisms. Current evidence strongly supports that anti-fatigue peptides may relieve exercise-induced fatigue via multiple mechanisms, including participation and regulation of energy metabolism; inhibition of inflammatory responses; reduction of reactive oxygen species content; and regulation of neurotransmitters, etc. In conclusion, the review provides key research perspectives to inform further research on anti-fatigue peptides for the food industry

    Current Perspectives on Viable but Non-Culturable Foodborne Pathogenic Bacteria: A Review

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    Foodborne diseases caused by foodborne pathogens pose risks to food safety. Effective detection and efficient inactivation of pathogenic bacteria has always been a research hotspot in the field of food safety. Complicating these goals, bacteria can be induced to adopt a viable but non-culturable (VBNC) state under adverse external environmental stresses. When in the VBNC state, pathogens cannot form visible colonies during traditional culture but remain metabolically active and toxic. The resulting false negative results in growth-related assays can jeopardize food safety. This review summarizes the latest research on VBNC foodborne pathogens, including induction conditions, detection methods, mechanism of VBNC formation, and possible control strategies. It is hoped that this review can provide ideas and methods for future research on VBNC foodborne pathogenic bacteria

    Role of intestinal microecology in the regulation of energy metabolism by dietary polyphenols and their metabolites.

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    Background: Polyphenols are a class of plant secondary metabolites with a variety of physiological functions. Polyphenols and their intestinal metabolites could greatly affect host energy metabolism via multiple mechanisms. Objective: The objective of this review was to elaborate the role of intestinal microecology in the regulatory effects of dietary polyphenols and their metabolites on energy metabolism. Methods: In this review, we illustrated the potential mechanisms of energy metabolism regulated by the crosstalk between polyphenols and intestinal microecology including intestinal microbiota, intestinal epithelial cells, and mucosal immune system. Results: Polyphenols can selectively regulate the growth of susceptible microorganisms (eg. reducing the ratio of Firmicutes to Bacteroides, promoting the growth of beneficial bacteria and inhibiting pathogenic bacteria) as well as alter bacterial enzyme activity. Moreover, polyphenols can influence the absorption and secretion of intestinal epithelial cells, and alter the intestinal mucosal immune system. Conclusion: The intestinal microecology play a crucial role for the regulation of energy metabolism by dietary polyphenols

    Activity and mechanism of vanadium sulfide for organic contaminants oxidation with peroxymonosulfate

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    Transition metal sulfides have been demonstrated to be effective for peroxymonosulfate (PMS) activation towards wastewater treatment. However, the activity of vanadium sulfide (VS4) and the role of the chemical state of V have not been revealed. Here, three types of VS4 with various morphologies and chemical states of V were synthesized by using methanol (M−VS4, nanosphere composed of nanosheets), ethanol (E-VS4, sea urchin like nanosphere) and ultrapure water (U-VS4, compact nanosphere) as hydrothermal solvent, respectively, and used as heterogeneous catalysts to activate PMS for the degradation of refractory organic pollutants. The effects of PMS concentration, temperature, pH, inorganic ions, and humic acid (HA) on the degradation efficiency of VS4/PMS system were investigated systematically. The results indicated that the highest specific surface area and lowest ratio of V5+ enable E-VS4/PMS system possessed the highest performance in degrading tetracycline hydrochloride (TCH), in which 100% TCH was removed after operating 10 min (0.805 min−1) under a relatively low concentration of PMS (1 mM) and catalyst (100 mg/L). It also revealed that the system exhibited a typical radical process in TCH degradation, which could be attributed to the redox cycles between V5+, V4+ and V3+ in the presence of PMS to generate various radicals. This radical process enabled the E-VS4/PMS system with a high activity in wide reaction conditions and high mineralization ratios in degrading various refractory organic pollutants within 10 min. In addition, the E-VS4/PMS system exhibited favorable reusability and stability with very less V and S ions leaching, and showed excellent performance in real water purification

    Application of curcumin-mediated antibacterial photodynamic technology for preservation of fresh Tremella Fuciformis

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    Tremella Fuciformis is an edible fungus with high water content and nutritional values. However, fresh T. Fuciformis can quickly lose its quality by physical damage, water loss and microbial degradation during storage. Herein, we evaluated the effects of curcumin-mediated photodynamic technology (PDT) using light-emitting diode (LED) light to preserve fresh T. Fuciformis. Changes in bacterial counts and community, physicochemical properties, and sensory attributes of curcumin-mediated PDT-treated fresh T. Fuciformis were assessed. The results indicated that treatment with 30 μmol/L curcumin and 30 min of LED light exposure could reduce bacterial counts by ~1.99 ± 0.06 log (CFU/g) in fresh T. Fuciformis upon 5 days storage. The bacterial microbiota in T. Fuciformis during storage was also altered upon PDT treatment. PDT treatment also retained the color, water content, hardness, tactility, and appearance of fresh T. Fuciformis. In conclusion, this study demonstrated that curcumin-mediated PDT could be a viable and promising non-thermal technology for preserving the quality of fresh T. Fuciformis

    Efficient pollutant removal using tetrahydrofuran functionalized carbon nitride nanosheets with enhanced photocatalytic performance

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    Photocatalysis offers a green and promising strategy for light-driven pollutant degradation to address water pollution. Yet, challenges in conversion efficiency and cost-efficiency propel the search for effective metal-free photocatalysts. Here, we employ a ball milling technique using organic solvent molecules to enhance the exfoliation of g-C3N4 nanosheets. Incorporating tetrahydrofuran, with its distinctive five-membered monooxygenase ring structure, endows exfoliated CN nanosheets (TCN) with remarkable electron-donating capabilities, expanding specific surface area and active sites, essential for intricate photocatalytic reactions. Comparative assessments unequivocally establish TCN's superiority, revealing a remarkable 3.6-fold enhancement in RhB dye degradation and a remarkable 99.7 % removal efficiency. TCN demonstrates rapid, complete reduction of heavy metal ions (Cr6+) under natural sunlight within 10 min and exhibits a significant 2.3-fold antibiotic degradation enhancement over pristine CN. This pioneering work unveils the mechanisms behind TCN's superior photocatalytic performance, offering insights into designing advanced photocatalysts for crucial water purification applications

    A far-UV survey of three hot, metal-polluted white dwarf stars: WD0455-282, WD0621-376, and WD2211-495

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    Using newly obtained high-resolution data (R ∼ 1 × 10^5) from the Hubble Space Telescope, and archival UV data from the Far Ultraviolet Spectroscopic Explorer, we have conducted a detailed UV survey of the three hot, metal-polluted white dwarfs WD0455−282, WD0621−376, and WD2211−495. Using bespoke model atmospheres, we measured Teff, log g, and photospheric abundances for these stars. In conjunction with data from Gaia, we measured masses, radii, and gravitational redshift velocities for our sample of objects. We compared the measured photospheric abundances with those predicted by radiative levitation theory, and found that the observed Si abundances in all three white dwarfs, and the observed Fe abundances in WD0621−376 and WD2211−495, were larger than those predicted by an order of magnitude. These findings imply not only an external origin for the metals, but also ongoing accretion, as the metals not supported by radiative levitation would sink on extremely short time-scales. We measured the radial velocities of several absorption features along the line of sight to the three objects in our sample, allowing us to determine the velocities of the photospheric and interstellar components along the line of sight for each star. Interestingly, we made detections of circumstellar absorption along the line of sight to WD0455−282 with three velocity components. To our knowledge, this is the first such detection of multicomponent circumstellar absorption along the line of sight to a white dwarf

    Origin of the turn-on temperature behavior in WTe2.

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    A hallmark of materials with extremely large magnetoresistance (XMR) is the transformative turn-on temperature behavior: when the applied magnetic field H is above certain value, the resistivity versus temperature ρ(T ) curve shows a minimum at a field dependent temperature T ∗, which has been interpreted as a magnetic-field-driven metal-insulator transition or attributed to an electronic structure change. Here, we demonstrate that ρ(T ) curves with turn-on behavior in the newly discovered XMR material WTe2 can be scaled as MR ∼ (H/ρ0) m with m ≈ 2 and ρ0 being the resistivity at zero field. We obtained experimentally and also derived from the observed scaling the magnetic field dependence of the turn-on temperature T ∗ ∼ (H − Hc) ν with ν ≈ 1/2, which was earlier used as evidence for a predicted metal-insulator transition. The scaling also leads to a simple quantitative expression for the resistivity ρ∗ ≈ 2ρ0 at the onset of the XMR behavior, which fits the data remarkably well. These results exclude the possible existence of a magnetic-field-driven metal-insulator transition or significant contribution of an electronic structure change to the low-temperature XMR in WTe2. This work resolves the origin of the turn-on behavior observed in several XMR materials and also provides a general route for a quantitative understanding of the temperature dependence of MR in both XMR and non-XMR materials
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