ABSTRACT
Oxygen-containing functional groups on the surface of carbon materials can promote the adsorption capacity of radioactive thorium ions (Th(IV)), but their effect on the adsorption of Th(IV) has not been systematically revealed. Herein, to elucidate the nature of oxygen-containing group-mediated Th(IV) adsorption, a series of graphene oxide nanoflakes (GONFs) with diï¬erent contents of oxygen-containing groups on the surface were prepared. The experimental results showed that the high adsorption of Th(IV) not only resulted from the oxygen content, but also was related to the type of oxygen-containing functional groups on GONFs. Subsequent density functional theory (DFT) calculations revealed that the high adsorption capacity for Th(IV) originated from the oxygen-containing groups and their adjacent activated sp2 carbon atoms. More importantly, the coordination of Th(IV) with oxygen functional groups induced the aggregation of GONFs, leading to the sedimentation of GONFs, which facilitated the separation of adsorbents and enabled the GONFs to be a more practical adsorbent for Th(IV). This work deepens our understanding of the role of oxygen-containing groups on Th(IV) adsorption and provides a new strategy for the design and synthesis of high-performance surface oxygen-containing carbon-based adsorbents with practical application potential.
ABSTRACT
The viability of cartilage explants preserved in vitro decreases with time, which limits its use for transplantation. The effect of mechanical stimulation to cartilage explants in vitro is unknown. In this study, we observed the effects of mechanical stimulation on chondrocyte viability and the mechanical properties of cartilage explants preserved in vitro using a rolling-sliding loading device designed by us, and the optimal stimulation protocol was established. A cylindrical osteochondral mass drilled on the femoral condyle of a healthy pig was divided into two groups (loading group and control group), and changes in the chondrocyte survival rate, matrix composition and cartilage biomechanical properties was observed at different time points. Additionally, the mRNA expression of the apoptosis-related proteins caspase-3/Bax/Bcl-2, the cytoskeletal proteins actin/vimentin, and the matrix-related protein MMP13 were detected. The loading group exhibited delayed collagen and aggrecan degeneration and improved chondrocyte viability for three days. Protein and mRNA detection showed that apoptotic factors such as caspase-3 and Bax decreased rapidly in cartilage tissue after loading. The cytoskeletal proteins actin and vimentin showed no significant changes in mRNA expression in the control group, but was significantly higher in the loading group. MMP-13 mRNA expression was significantly higher in both the control group and loading group. Overall, this study suggests that suitable mechanical stimulation decreases the loss of chondrocyte viability and the mechanical properties of cartilage explants in vitro and improves cartilage preservation.
Subject(s)
Cartilage, Articular/cytology , Chondrocytes/cytology , Tissue Culture Techniques/instrumentation , Animals , Apoptosis , Biomechanical Phenomena , Cell Survival , Cells, Cultured , Equipment Design , Pressure , Stress, Mechanical , SwineABSTRACT
A novel moderately thermophilic and heterotrophic ammonia-oxidizing bacterium, designated strain BM62T, was isolated from compost in the thermophilic stage in Harbin, China. Phylogenetic analysis based on the 16S rRNA gene indicated that strain BM62T belongs to the family Bacillaceae within the class Bacilli and was most closely related to Alteribacillus iranensis X5BT (only 94.6% sequence similarity). Cells of strain BM62T were Gram-positive, rod-shaped, motile by periflagella, catalase-positive and oxidase-negative. Growth of strain BM62T was observed at salinities of 0-4% (optimum 2-3%), temperatures of 35-65 °C (optimum 50 °C) and pH values of 5-9 (optimum pH 7). The major cellular fatty acid was iso-C16:0, and the predominant ubiquinone was MK-7. The peptidoglycan type is A1γ, and meso-diaminopimelic acid was the diagnostic diamino acid. The major polar lipids were diphosphatidylglycerol, phospholipid and phosphatidylglycerol. The G + C content of its genomic DNA was 36.5 mol%. Data from this polyphasic taxonomy study suggested that strain BM62T should be classified as the type strain of the type species of a new genus within the family Bacillaceae for which the name Aliibacillus thermotolerans gen. nov., sp. nov. is proposed. The type strain of the species Aliibacillus thermotolerans sp. nov. is BM62T (= DSM 101851T = CGMCC 1.15790T). The respective DPD Taxon Number is GA00057.
