Arsenic distribution characteristics and release mechanisms in aquaculture lake sediments.

It is well known that aquaculture can alter the microenvironments of lakes at sediment-water interface (SWI). However, the main mechanisms underlying the effects of aquaculture activities on arsenic (As) transformations are still unclear. In this context, the present study aims to investigate the variations in the sediment As contents in Yangcheng Lake, as well as to assess its chemical transformations, release fluxes, and release mechanisms. The results showed substantial spatial differences in the dissolved As concentrations in the sediment pore water. The As release fluxes at the SWI ranged from 1.32 to 112.09 µg/L, with an average value of 33.68 µg/L. In addition, the highest As fluxes were observed in the aquaculture areas. The transformation of crystalline hydrous Fe oxide-bound As to adsorbed-As in the aquaculture lake sediments increased the ability of As release. The Partial least squares path modeling results demonstrated the great contributions of organic matter (OM) to the As transformations by influencing the sediment microbial communities and Fe/Mn minerals. The changes in the As fractionation and competing adsorption increased the dissolved As concentrations in the 0-10 mm surface sediment. Non-specifically and specifically adsorbed As were the major sources of dissolved As in the sediments. Specifically, microbial reduction of As[V] and dissolution of Fe oxides increased the dissolved As concentrations at the SWI (20 to -20 mm). The results of the current study highlight the positive enhancement effects of aquaculture on As release from sediments.

Hyaluronic acid methacrylate/laponite hydrogel loaded with BMP4 and maintaining its bioactivity for scar-free wound healing.

Scar-free wound healing is a challenging process due to the excessive deposition of extracellular matrix and collagen. To overcome this issue, hydrogels with superior biochemical and mechanical properties have been used in combination with medicinal compounds as wound dressings. In this study, a novel composite hydrogel consisting of double-crosslinked photocurable hyaluronic acid methacrylate (HAMA) and Laponite (Lap) loaded with bioactive bone morphogenetic protein 4 (BMP4) was developed and thoroughly characterized for its properties such as degradation, morphology, porosity, compression, skin adhesion and load release. The effect of the HAMA/Lap/BMP4 hydrogel was evaluated through both in vitro and in vivo experiments. In the in vivo rabbit ear-scar model, the HAMA/Lap/BMP4 hydrogel dressing was found to reduce scar-related expressions of α-SAM and decrease the ratio of collagen Ι/III in wounded tissue. Additionally, histopathological examination indicated that the HAMA/Lap/BMP4 hydrogel-treated groups exhibited enhanced wound repair and increased levels of collagen maintenance compared to other standard groups, ultimately leading to scarless wound healing. Therefore, this sustained-release photocurable HAMA/Lap/BMP4 hydrogel offers a therapeutic approach for scar-free wound healing.