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The Yangtze River Economic Belt (YREB) is an important strategic area in China. However, frequent extreme precipitation events have caused great economic losses and human casualties in this region. In this article, we explore the spatial and temporal links between extreme precipitation events and Sunspot Number (SSN), El Niño Southern Oscillation (ENSO), Arctic Oscillation (AO) and Pacific Decadal Oscillation (PDO) in this important economic belt. According to the research findings, all of the extreme precipitation indices (EPIs) except for consecutive dry days (CDD) and consecutive wet days (CWD) showed an upward trend in the YREB over the 59 years. The spatial distributions of very wet days (R95p), extremely wet days (R99p), max 1-day precipitation amount (Rx1day) and max 5-day precipitation amount (Rx5day) had similar distribution patterns, showing decreasing trends from east to west. The EPIs generally had a 2–4-year band, suggesting stronger and more elusive changes. The wavelet coherence (WTC) spectra suggested that SSN, ENSO, AO, and PDO have different effects on extreme precipitation events during different time periods. Before 1985, the SSN, ENSO, AO, PDO and extreme precipitation events shared similar oscillation periods, but after 1985, their oscillation periods were no longer consistent with each other. In addition, solar activity and the AO mainly had negative correlations with extreme precipitation events, while the ENSO and PDO had predominantly positive correlations with the EPIs. This paper provides a reference for national economic strategic planning and natural resource management in the YREB. [ABSTRACT FROM AUTHOR]

Nanoparticle-based drug delivery systems have become a favourable platform for target specificity in disease treatment, although their side effects and toxicity remain controversial. Plant polysaccharide nanoparticles are safe, natural biomaterials that have become candidate materials for nano-drug delivery systems due to their excellent biodegradability and biocompatibility. In addition to becoming candidate materials, plant polysaccharide nanoparticles show excellent pharmacokinetic and drug delivery characteristics as carrier materials to manipulate small drug molecules at the nanoscale, mainly improving medicine solubility, reducing medicine toxicity and side effects and enhancing biological targeting of medicines. Therefore, the application of plant polysaccharide nanoparticles in the field of drug delivery systems may become the focus of future studies. Here we review the carrier function of plant polysaccharide nanoparticles as a polymeric material in drug delivery. The limitations and challenges of applying plant polysaccharide nanoparticles in drug carrier systems are highlighted with the aim to provide a reference for their precise development. [ABSTRACT FROM AUTHOR]

Dense smoke released during the combustion of polystyrene (PS) potentially limits its applications in some fields. In this study, a Zr-based metal-organic framework (UiO-66) was prepared via the solvothermal method and added to PS to suppress its smoke emission. Well-defined UiO-66 particles showed an excellent dispersion state and good compatibility in the PS matrix. The introduction of UiO-66 improved the flame retardancy and smoke suppression of PS. The peak heat-release rate and total heat release were reduced by 26.8% and 14.7%, respectively, for PS/ UiO-66-5 wt%. Moreover, the smoke emissions of PS composites were evidently suppressed, and more than a 35% reduction in total smoke production was obtained with 5-wt% UiO-66. Through the analysis of the residues and pyrolysis products of PS composites, the mechanisms of enhanced flame retardancy and smoke suppression can being speculated as the promoted char-forming and heat barrier of UiO-66. This work offers a significant reference for the further study of UiO-66 and polymer materials. [ABSTRACT FROM AUTHOR]

The creep model is the main form of rock model used to describe the rheological behavior of rocks. A large number of creep models have been proposed, but many are complicated and/or are not able to fully simulate the three stages of rock creep. Hence, an important focus of research on rock creep has been to develop a model with few parameters and better simulation performance. To achieve this, in this study, we propose a new four-element creep model, based on variable-order fractional derivatives and continuum damage mechanics. The newly proposed creep model agrees well with experimental data for Changshan rock salt. The results show that the segmentation treatment is an effective approach for simulating the creep behavior of rocks. [ABSTRACT FROM AUTHOR]

Axial strain-time curves for a marble sample were obtained by performing uniaxial compression tests with step loading. Axial strain rate-time data points were then obtained from the axial strain-time curves. One power function and one exponential function were selected from the literature to fit the experimental creep data. Based on the characteristics of the plotted axial strain rate-time data points, one power function and one exponential function were proposed as possible functions to model the creep data. By comparing the goodness-of-fit of the aforementioned four functions through regression analysis, it was found that the two exponential functions fit the experimental creep data better than the two power functions. The two exponential functions showed very close goodness-of-fit levels on the experimental data. The proposed exponential function has only two parameters compared to that of the exponential function in the literature which has four parameters. Therefore, the proposed exponential function is selected as the creep model of marble. This model is also related to a built-up combined spring-dashpot model known as the generalized Kelvin model. The model parameter values of the generalized Kelvin model are then calculated by the parameter relations that exist between the generalized Kelvin model and the proposed exponential function. [ABSTRACT FROM AUTHOR]