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Microorganisms can colonize to the surface of microplastics (MPs) to form biofilms, termed "plastisphere", which could significantly change their physiochemical properties and ecological roles. However, the biofilm characteristics and the deep mechanisms (interaction, assembly, and biogeochemical cycles) underlying plastisphere in wetlands currently lack a comprehensive perspective. In this study, in situ biofilm formation experiments were performed in a park with different types of wetlands to examine the plastisphere by extrinsic addition of PVC MPs in summer and winter, respectively. Results from the spectroscopic and microscopic analyses revealed that biofilms attached to the MPs in constructed forest wetlands contained the most abundant biomass and extracellular polymeric substances. Meanwhile, data from the high-throughput sequencing showed lower diversity in plastisphere compared with soil bacterial communities. Network analysis suggested a simple and unstable co-occurrence pattern in plastisphere, and the null model indicated increased deterministic process of heterogeneous selection for its community assembly. Based on the quantification of biogeochemical cycling genes by high-throughput qPCR, the relative abundances of genes involving in carbon degradation, carbon fixation, and denitrification were significantly higher in plastisphere than those of soil communities. This study greatly enhanced our understanding of biofilm formation and ecological effects of MPs in freshwater wetlands., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

It is well known that metal ions have great effects on gelling behaviors of gellan aqueous systems, however, the effects of their co-ions - anions have rarely been studied. Herein, we investigated the effects of four kinds of sodium salts with different anions (NaCl, CH 3 COONa, Na 2 C 2 O 4 and Na 3 C 6 H 5 O 7 ) on gelling behaviors of gellan aqueous systems in terms of gelling temperature and gel hardness. It was found that, when [Na + ] was low (20 mM), the salt with Cl - or CH 3 COO - favored the gelling of gellan aqueous systems, while the salt with C 2 O 4 2- or C 6 H 5 O 7 3- took adverse effects probably because C 2 O 4 2- or C 6 H 5 O 7 3- could react with divalent cations (Ca 2+ and Mg 2+ ) in gellan to form precipitates or chelates and break their interactions with gellan (salt bridges). When [Na + ] was high (50 or 80 mM), all the four kinds of salts facilitated gelling due to the shielding effects of high concentrations of Na + on the negative charges along the gellan chains, and followed the order of: Cl - > CH 3 COO - > C 2 O 4 2- > C 6 H 5 O 7 3- . This study demonstrates the effects of anion kind of salts on gelling behaviors of gellan aqueous systems and provides references for the application of gellan., (Copyright © 2021. Published by Elsevier B.V.)

Hydroxyapatite (HA) combined with antimicrobial agents for biomedical application can effectively avoid the bacteria infection, while HA have the good performance. In this study, we prepared silver-hydroxyapatite (Ag-HA) nanocomposites using a one-pot method consisting of three sequential steps of wet chemical precipitation, ion exchange, and a silver mirror reaction. The HA nanoparticles used as the precursor for Ag ion doping were first synthesised by wet chemical precipitation. Next, Ag + absorbed on HA surface through ion exchange reaction. Glucose was then added to initiate the silver mirror reaction, which made the Ag + ions reduce to Ag 0 and Ag nanoparticles in situ formed on HA nanoparticles. Subsequently, Ag-HA nanocomposites with different Ag content were prepared. X-ray diffraction, SEM, EDX mapping and TEM imaging confirmed that spherical Ag nanoparticles ~20-40 nm in diameter were adhered to the surface of HA nano-rods (0.4-0.8 μm in length and 15-40 nm in diameter). The Ag content (1.9-15.2 wt%) in the Ag-HA nanocomposites was adjusted by varying the feeding Ag/Ca molar ratio (2.0-20%). The cell viability evaluation in vitro proved that Ag-HA nanocomposites had low cytotoxicity to L929 normal cells. Meanwhile, the antibacterial examinations in vitro demonstrated that Ag-HA nanocomposites had obvious antibacterial effects on Gram-positive bacteria, Gram-negative bacteria, and fungus. The antibacterial results were dose-dependent on the accumulation of silver content. The Ag-HA nanocomposites loaded PMMA resins also demonstrated a potential antibacterial activity against S. mutans. This paper presents a convenient and bio-friendly approach for preparing Ag-HA nanocomposites with adjustable Ag content, which are a promising material for biomedical applications., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The moisture sorption and desorption properties of hard capsules have a great influence on the quality of capsule products. However, studies on them have rarely been reported. Herein, we studied the moisture sorption and desorption properties of three kinds of hard capsules (gelatin, hydroxypropyl methyl cellulose (HPMC) and pullulan capsules) in terms of hygroscopicity, crystallinity, thermal behaviors and so on. It is found that HPMC capsules have weaker moisture sorption ability and moisture keeping ability than pullulan or gelatin capsules with lower moisture sorption rates, equilibrium moisture contents, moisture keeping rates and higher critical relative humidity. In comparison with gelatin capsules, pullulan capsules have weaker moisture sorption ability and comparable moisture keeping ability. HPMC or pullulan capsules can more effectively protect high, moderate and low hygroscopic capsule contents (chitosan, potato starch or ethyl cellulose) from outside moisture absorption. The diffraction peaks of the moisture equilibrated gelatin, HPMC and pullulan capsules are much smaller than those of their dried ones. The dried and the moisture equilibrated gelatin, HPMC or pullulan capsules all have smooth surface morphology. HPMC or pullulan capsules can be an attractive alternative to animal gelatin capsules due to their appropriate moisture sorption and desorption properties., Competing Interests: Declaration of competing interest None., (Copyright © 2020. Published by Elsevier B.V.)

Gelatinization is an important property of starch for biomedical applications. However, studies on the changes in starch granules in terms of morphology, swelling, amylose leaching and so on during gelatinization, which are key to uncovering the starch gelatinization process, have rarely been reported. Herein, changes of cassava and potato starch granules during gelatinization were investigated. It was found that there is a substantial difference in the granule changes during gelatinization between cassava and potato starch. Cassava starch granules remain intact with slight swelling, with approximately 8.5% amylose leaching in water for 30 min at 60 °C. In sharp contrast, potato starch granules swell very well and rapidly, losing much integrity with 51.05% amylose leaching. The gelatinization time and temperature have much greater effects on the changes of potato starch granules than cassava starch granules., (Copyright © 2018. Published by Elsevier B.V.)

Climate change and human activities have changed the spatial-temporal distribution of water resources, especially in a fragile ecological area such as the upper reaches of the Minjiang River (UMR) basin, where they have had a more profound effect. The average of double-mass curve (DMC) and Distributed Time-Variant Gain Hydrological Model (DTVGM) are applied to distinguish between the impacts of climate change and human activities on water resources in this paper. Results indicated that water resources decreased over nearly 50 years in the UMR. At the annual scale, contributions of human activities and climate change to changes in discharge were -77% and 23%, respectively. In general, human activities decreased the availability of water resources, whereas climate change increased the availability of water resources. However, the impacts of human activities and climate change on water resources availability were distinctly different on annual versus seasonal scales, and they showed more inconsistency in summer and autumn. The main causes of decreasing water resources are reservoir regulation, and water use increases due to population growth. The results of this study can provide support for water resource management and sustainable development in the UMR basin., (Copyright © 2018 Elsevier B.V. All rights reserved.)