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As one of the raw materials of basic magnesium sulfate cement (BMSC), the activity of light-burned magnesium oxide (MgO) has an important effect on the hydration rate, hydration products, and mechanical properties of BMSC. To reveal the influence of packaging method, storage environment, and storage time on the activity of MgO and the mechanical properties of BMSC, an experiment was conducted by using ordinary woven bags, peritoneal woven bags, and plastic and paper compound bags to store the finished BMSC and the raw materials (light-burned MgO, MgSO4·7H2O, fly ash, and a chemical additive) under the conditions of natural environment, sealed environment, and wet environment, respectively. Comparative analysis of the effects of packaging method, storage conditions, and storage time on the activity of MgO and the mechanical properties of BMSC was performed through the mechanical strength test of mortar specimens. The results showed that in a sealed environment, the loss of a-MgO content in light-burned MgO was minimized, which was more conducive to keeping the mechanical properties of BMSC stable. In the wet environment, the mechanical strength of BMSC was significantly reduced in the early stage (1 day) due to the significant reduction in the activity of MgO, and the mechanical strength of the finished BMSC and prepared BMSC after 120 days of storage was still lost, regardless of the packaging method. However, the storage environment and packaging method had relatively little effect on the late mechanical strength (28 days) of BMSC. It is advisable to use ordinary woven bags for packaging in natural and sealed environments as this is more economical for engineering applications. Plastic and paper compound bags are superior to ordinary woven bags and peritoneal woven bags in wet environments. [ABSTRACT FROM AUTHOR]

The stimulus-responsive drug delivery system has attracted increasing attention due to its ability to enhance therapeutic efficacy and reduce side effects. Herein, a pH and glutathione (GSH) dually responsive drug carrier, hollow silica--polyelectrolyte composite nanoparticle, was successfully prepared by using a template of spherical polyelectrolyte brush (SPB) which consists of a polystyrene (PS) core and a densely grafted linear poly(acrylic acid) (PAA) shell. The existence of PAA chains and introduction of disulfide bonds in silica framework endow the composite nanoparticles with pH and GSH dually responsive properties which were confirmed by dynamic light scattering (DLS) and small-angle X-ray scattering (SAXS). With doxorubicin hydrochloride (DOX) as the model drug, the loading content and encapsulation efficiency could reach up to 43% and 96%, respectively. The drug release behavior was investigated under various environments, showing that the drug release rate increased with the decrease in pH value and the increase in GSH concentration. The prepared hollow SiO2-PAA composite nanoparticles possess a great potential as carriers for controlled drug delivery. [ABSTRACT FROM AUTHOR]

Seagrass meadows play vital ecological roles in the marine ecosystem. Global climate change poses considerable threats to seagrass survival. However, it is unclear how seagrass and its associated bacteria will respond under future complex climate change scenarios. This study explored the effects of ocean warming (+2 °C) and ocean acidification (−0.4 units) on seagrass physiological indexes and bacterial communities (sediment and rhizosphere bacteria) of the seagrass Thalassia hemprichii during an experimental exposure of 30 days. Results demonstrated that the synergistic effect of ocean warming and ocean acidification differed from that of one single factor on seagrass and the associated bacterial community. The seagrass showed a weak resistance to ocean warming and ocean acidification, which manifested through the increase in the activity of typical oxidoreductase enzymes. Moreover, the synergistic effect of ocean warming and ocean acidification caused a significant decrease in seagrass's chlorophyll content. Although the bacterial community diversity exhibited higher resistance to ocean warming and ocean acidification, further bacterial functional analysis revealed the synergistic effect of ocean warming and ocean acidification led to significant increases in SOX-related genes abundance which potentially supported the seagrass in resisting climate stress by producing sulfates and oxidizing hydrogen sulfide. More stable bacterial communities were detected in the seagrass rhizosphere under combined ocean warming and ocean acidification. While for one single environmental stress, simpler networks were detected in the rhizosphere. In addition, the observed significant correlations between several modules of the bacterial community and the physiological indexes of the seagrass indicate the possible intimate interaction between seagrass and bacteria under ocean warming and ocean acidification. This study extends our understanding regarding the role of seagrass associated bacterial communities and sheds light on both the prediction and preservation of the seagrass meadow ecosystems in response to global climate change. • The combined stress of warming and acidification significantly decreased seagrass chlorophyll content. • Warming and acidification together led to higher seagrass associated bacterial community stability and elevated SOX-related gene abundance. • Seagrass and its rhizosphere bacteria potentially co-response to the synergistic effect of warming and acidification. [ABSTRACT FROM AUTHOR]

Long-term cultivation tends to cause thinning and even partial disappearance of Mollisols, which largely limits the sustainable development of agriculture. Cultivation duration greatly affects soil pore structure and biochemical properties of Mollisols. This study aims to elucidate the response of aggregate pore structure, stability, and biochemical properties of soil during degradation under long-term cultivation in Mollisols. The study involved four croplands with different cultivation durations (20, 40, 60, and 100 years; designated as AL20, AL40, AL60, and AL100, respectively) and one undisturbed forest land (FR). Samples were collected from three soil depths (0–20, 20–40, and 40–60 cm). Pore structure and biochemical properties were analyzed by X-ray Computed Tomography (CT) and standard method. As a result, the aggregate stability and biochemical properties of soil showed different degrees of degradation with the extension of cultivation duration. The mean weight diameter, soil organic carbon, total nitrogen, and microbial biomass carbon followed the order of AL20 > FR > AL40 > AL60 > AL100, while the soil bulk density exhibited an opposite trend. FR and AL20 showed significant differences from other sites (P < 0.05). The CT results revealed that total porosity and pore number approximately decreased with cultivation duration, with their maximum appearing in FR and minimum occurring in AL100. The pore shape and pore size of aggregates were dominated by elongated pores (> 65%) and porosity > 100 µm, respectively, both of which declined with increasing cultivation duration. Similarly, the fractal dimension and connectivity were the highest in FR. These results demonstrated that the pore structure of soil aggregates tended to be "simplified" with increasing cultivation duration. Soil structure index, which varied significantly with cultivation duration, was used to comprehensively evaluate the soil structure. The results provide important insights into soil structural degradation caused by long-term cultivation. [Display omitted] • X-ray CT can be used to investigate aggregate pore structure. • Long-term tillage restrained SOC content, pore development, and aggregate stability. • Elongated pore and P >100 µm were the main pore shape and pore size respectively. • Aggregate pore structure tended to be "simplified" with increasing cultivation duration. • MWD, FD, P 30–75 μm , P 75–100 μm , and DA, and MSF were selected to construct SSI. [ABSTRACT FROM AUTHOR]