Effect of water-soluble polymers on the transport of functional group-modified polystyrene nanoplastics in goethite-coated saturated porous media.

The research on the impact of water-soluble polymers (WSPs) on the migration and fate of plastic particles is extremely limited. This article explored the effects of polyacrylic acid (PAA, a common WSP) and physicochemical factors on the transport of polystyrene nanoparticles (PSNPs-NH2/COOH) with different functional groups in QS (quartz sand) and FOS (goethite-modified quartz sand, simulates mineral colloids). Research has shown that PAA can selectively adsorb onto the surface of PSNPs-NH2, forming ecological corona heterogeneous aggregates. This process increased the spatial hindrance and elastic repulsion, resulting in the recovery of PSNPs-NH2 always exceeding that of PSNPs-COOH. Overall, PAA can hinder the migration of PSNPs in QS but can promote their migration in FOS. When multivalent cations coexist with PAA, the transport of PSNPs in the media is primarily affected by cation bridging and CH-cation-π interaction. The presence of oxyanions and PAA prevents PSNPs from following the Hofmeister rule and promotes their migration (PO43-: 82.34 ± 0.16% to 94.63 ± 2.82%>SO42-: 81.38 ± 2.73% to 91.15 ± 0.93%>NO3-: 55.85 ± 0.70%-87.16 ± 3.80%). The findings of this study contribute significantly to a better understanding of the migration of WSPs and group-modified NPs in complex saturated porous media.

Co-transport of degradable microplastics with Cd(â ¡) in saturated porous media: Synergistic effects of strong adsorption affinity and high mobility.

With the utilization of degradable plastics in the agricultural film and packaging industries, degradable microplastics (MPs) with strong mobility distributed in the underground environment may serve as carriers for heavy metals. It is essential to explore the interaction of (aged) degradable MPs with Cd(Ⅱ). The adsorption and co-transport behavior of different types of (aged) MPs (polylactic acid (PLA), polyvinyl chloride (PVC)) with Cd(Ⅱ) were investigated through batch adsorption experiments and column experiments under different conditions, respectively. The adsorption results showed that the adsorptive capacity of (aged) PLA with O-functional groups, polarity, and more negative charges was stronger than that of PVC and aged PVC, which was attributed to the binding of (aged) PLA to Cd(Ⅱ) through complexation and electrostatic attraction. The co-transport results indicated that the promotion of Cd(Ⅱ) transport by MPs followed the order of aged PLA > PLA > aged PVC > PVC. This facilitation was more pronounced under conditions of stronger transport of MPs and favorable attachment of Cd(Ⅱ) to MPs. Overall, the combination of strong adsorption affinity and high mobility helped (aged) PLA act as effective carriers for Cd(Ⅱ). The DLVO theory well explains the transport behavior of Cd(Ⅱ)-MPs. These findings provide new insights into the co-transport of degradable MPs and heavy metals in the subsurface environment.

Effect of different aging treatments on the transport of nano-biochar in saturated porous media.

Widely used for soil amendment, carbon sequestration, and remediation of contaminated soils, biochars (BCs) inevitably produce a large number of nanoparticles with relatively high mobility. Geochemical aging alters chemical structure of these nanoparticles and thus affect their colloidal aggregation and transport behavior. In this study, the transport of ramie derived nano-BCs (after ball-milling) was investigated by different aging treatments (i.e., photo (PBC) and chemical aging (NBC)) as well as the managing BC under different physicochemical factors (i.e., flow rates, ionic strengths (IS), pH, and coexisting cations). Consequences of the column experiments indicated aging promoted the mobility of the nano-BCs. Compared to the nonaging BC, consequences of spectroscopic analysis demonstrated the aging BCs exhibited a number of tiny corrosion pores. Both of these aging treatments contribute to a more negative zeta potential and a higher dispersion stability of the nano-BCs, which is caused by the abundance of O-functional groups. Also the specific surface area and mesoporous volume of both aging BCs increased significantly, with the increase being more pronounced for NBC. The breakthrough curves (BTCs) obtained for the three nano-BCs were modelled by the advection-dispersion equation (ADE), which included first-order deposition and release terms. The ADE revealed high mobility of aging BCs, which meant their retention in saturated porous media was reduced. This work contributes to a comprehensive understanding of the transport of aging nano-BCs in the environment.

PLA2G16 Expression in Human Osteosarcoma Is Associated with Pulmonary Metastasis and Poor Prognosis.

BACKGROUND: Osteosarcoma is the most frequent type of malignant bone tumor in children and adolescents and is associated with a high propensity for lung metastasis. Recent experiments have indicated that PLA2G16 contributes to osteosarcoma progression and metastasis in both mouse and human osteosarcoma cell lines. The aim of this study was to compare the expression of PLA2G16 in non-metastatic and metastatic osteosarcomas to determine whether PLA2G16 expression can serve as a biomarker of osteosarcoma prognosis and metastasis. METHODS: Quantitative real-time PCR was used to examine PLA2G16 mRNA in primary osteosarcoma patients (18 patients without metastases and 17 patients with metastases), and immunohistochemistry (IHC) staining of PLA2G16 was performed on tissue microarrays from 119 osteosarcoma patients. Tumor metastatic behavior and survival of the patients were followed up for a minimum of 36 months and a maximum of 171 months. The prognostic value of PLA2G16 expression was evaluated by the Kaplan-Meier method and a log-rank test. Multivariate Cox regression analysis was used to identify significant independent prognostic factors. RESULTS: Osteosarcoma patients with metastasis showed a higher expression of PLA2G16 at both the mRNA and protein levels (both at P values< 0.05) than did patients without metastasis. Osteosarcoma patients with positive IHC staining of PLA2G16 expression at primary sites had shorter overall survival and metastasis-free survival (both at P values <0.02). Moreover, multivariate Cox analysis identified PLA2G16 expression as an independent prognostic factor to predict poor overall survival and metastasis-free survival (both P values < 0.03). CONCLUSIONS: This study indicated that PLA2G16 expression is a significant prognostic factor in primary osteosarcoma patients for predicting the development of metastases and poor survival.