Heteroaggregation and deposition behaviors of carboxylated nanoplastics with different types of clay minerals in aquatic environments: Important role of calcium(II) ion-assisted bridging.

The widespread utilization of plastic products ineluctably leads to the ubiquity of nanoplastics (NPs), causing potential risks for aquatic environments. Interactions of NPs with mineral surfaces may affect NPs transport, fate and ecotoxicity. This study aims to investigate systematically the deposition and aggregation behaviors of carboxylated polystyrene nanoplastics (COOH-PSNPs) by four types of clay minerals (illite, kaolinite, Na-montmorillonite, and Ca-montmorillonite) under various solution chemistry conditions (pH, temperature, ionic strength and type). Results demonstrate that the deposition process was dominated by electrostatic interactions. Divalent cations (i.e., Ca2+, Mg2+, Cd2+, or Pb2+) were more efficient for screening surface negative charges and compressing the electrical double layer (EDL). Hence, there were significant increases in deposition rates of COOH-PSNPs with clay minerals in suspension containing divalent cations, whereas only slight increases in deposition rates of COOH-PSNPs were observed in monovalent cations (Na+, K+). Negligible deposition occurred in the presence of anions (F-, Cl-, NO3-, CO32-, SO42-, or PO43-). Divalent Ca2+ could incrementally facilitate the deposition of COOH-PSNPs through Ca2+-assisted bridging with increasing CaCl2 concentrations (0-100 mM). The weakened deposition of COOH-PSNPs with increasing pH (2.0-10.0) was primarily attributed to the reduce in positive charge density at the edges of clay minerals. In suspensions containing 2 mM CaCl2, increased Na+ ionic strength (0-100 mM) and temperature (15-55 ◦C) also favored the deposition of COOH-PSNPs. The ability of COOH-PSNPs deposited by four types of clay minerals followed the sequence of kaolinite > Na-montmorillonite > Ca-montmorillonite > illite, which was related to their structural and surface charge properties. This study revealed the deposition behaviors and mechanisms between NPs and clay minerals under environmentally representative conditions, which provided novel insights into the transport and fate of NPs in natural aquatic environments.

Carbazolic Conjugated Microporous Polymers for Photocatalytic Organic Transformations.

Heterogeneous photocatalysis have been deemed as a versatile and colorful platform for exploring efficient transformation systems. Henceforth, the design of photocatalysts underpins a wide range of research interests. By virtue of synthetic versatility, stability, non-toxicity, purely organic properties, tunable semiconductive structures, and remarkable visible-light absorbance, conjugated microporous polymers (CMPs) have emerged as an attractive new class of semiconductor materials that show great potential for tackling important energy and environmental challenges. Over the past decade, immense efforts have been devoted toward the construction of CMPs-based photocatalysts for versatile photocatalytic transformations. This review aims to summarize the latest representative advances in the field of carbazolic CMPs, focusing on various design strategies for the construction of tailor-made skeletons that have direct impact on their charge dynamics and thus photocatalytic performances, especially on their specific photocatalytic efficiency for organic transformations. Scrutinizing the photocatalytic features and elucidating the related design principles, it is fully described how structure modification of polycarbazoles could have an effect on optical properties, and thus on photocatalytic performance. Furthermore, the bottlenecks that need to be addressed, and the future research directions of CMPs are identified in the area of photocatalysis.

Differential impacts of microplastics on carbon and nitrogen cycling in plant-soil systems: A meta-analysis.

Microplastics (MPs) are widely present in terrestrial ecosystems. However, how MPs impact carbon (C) and nitrogen (N) cycling within plant-soil system is still poorly understood. Here, we conducted a meta-analysis utilizing 3338 paired observations from 180 publications to estimate the effects of MPs on plant growth (biomass, nitrogen content, nitrogen uptake and nitrogen use efficiency), change in soil C content (total carbon (TC), soil organic carbon (SOC), dissolved organic carbon (DOC), microbial biomass carbon (MBC)), C losses (carbon dioxide (CO2) and methane), soil N content (total nitrogen, dissolved organic nitrogen, microbial biomass nitrogen, total dissolve nitrogen, ammonium, nitrate (NO3--N) and nitrite) and nitrogen losses (nitrous oxide, ammonia (NH3) volatilization and N leaching) comprehensively. Results showed that although MPs significantly increased CO2 emissions by 25.7 %, they also increased TC, SOC, MBC, DOC and CO2 by 53.3 %, 25.4 %, 19.6 % and 24.7 %, respectively, and thus increased soil carbon sink capacity. However, MPs significantly decreased NO3--N and NH3 volatilization by 14.7 % and 43.3 %, respectively. Meanwhile, MPs significantly decreased plant aboveground biomass, whereas no significant changes were detected in plant belowground biomass and plant N content. The impacts of MPs on soil C, N and plant growth varied depending on MP types, sizes, concentrations, and experimental durations, in part influenced by initial soil properties. Overall, although MPs enhanced soil carbon sink capacity, they may pose a significant threat to future agricultural productivity.

Regulating Tumor-Associated Macrophage Polarization by Cyclodextrin-Modified PLGA Nanoparticles Loaded with R848 for Treating Colon Cancer.

Purpose: This study aimed to develop a novel and feasible modification strategy to improve the solubility and antitumor activity of resiquimod (R848) by utilizing the supramolecular effect of 2-hydroxypropyl-beta-cyclodextrin (2-HP-ß-CD). Methods: R848-loaded PLGA nanoparticles modified with 2-HP-ß-CD (CD@R848@NPs) were synthesized using an enhanced emulsification solvent-evaporation technique. The nanoparticles were then characterized in vitro by several methods, such as scanning electron microscopy (SEM), differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) spectroscopy, particle size analysis, and zeta potential analysis. Then, the nanoparticles were loaded with IR-780 dye and imaged using an in vivo imaging device to evaluate their biodistribution. Additionally, the antitumor efficacy and underlying mechanism of CD@R848@NPs in combination with an anti-TNFR2 antibody were investigated using an MC-38 colon adenocarcinoma model in vivo. Results: The average size of the CD@R848@NPs was 376 ± 30 nm, and the surface charge was 21 ± 1 mV. Through this design, the targeting ability of 2-HP-ß-CD can be leveraged and R848 is delivered to tumor-supporting M2-like macrophages in an efficient and specific manner. Moreover, we used an anti-TNFR2 antibody to reduce the proportion of Tregs. Compared with plain PLGA nanoparticles or R848, CD@R848@NPs increased penetration in tumor tissues, dramatically reprogrammed M1-like macrophages, removed tumors and prolonged patient survival. Conclusion: The new nanocapsule system is a promising strategy for targeting tumor, reprogramming tumor -associated macrophages, and enhancement immunotherapy.

Modified presurgical nasoalveolar molding for patients with neonatal complete bilateral cleft lip and palate having a severely malpositioned premaxilla.

OBJECTIVE: To develop a modified presurgical nasoalveolar molding (MPNAM) with a premaxillary appliance, connected with two stainless steel wires and evaluate its therapeutic efficacy in newborns with complete bilateral cleft lip and palate (BCLP). METHOD: A total of 41 patients with neonatal complete BCLP having a severely protruded and deviated premaxilla were retrospectively selected from January 2017 to November 2019. All patients received the MPNAM device with a premaxillary appliance which was worn until cheilorrhaphy. Plaster casts from pre- and post-MPNAM treatments were scanned using a three-dimensional laser scanner, and the changes were recorded. Facial photographs of patients were taken during the treatment. RESULT: The average MPNAM treatment duration was 59.8 days. In all cases, the protrusive and deviated premaxilla was rapidly retracted and set into a suitable position after MPNAM treatment. The relative deviation distance and alveolar cleft width were significantly reduced. Both mid-palatal arch width and posterior arch width were increased. In addition, none of the patients developed any complications during the MPNAM treatment. CONCLUSION: Our MPNAM device was able to rapidly centralize the malpositioned premaxilla and reduce the alveolar cleft defect. This device can be applied in presurgical orthodontic treatments for patients with complete BCLP having a severely protruded and deviated premaxilla.

An ultrasensitive homogeneous aptasensor for carcinoembryonic antigen based on upconversion fluorescence resonance energy transfer.

Carcinoembryonic antigen (CEA) has been recognized as one of the most important tumor markers. Herein, we reported an ultrasensitive homogeneous aptasensor based on fluorescence resonance energy transfer (FRET) between upconversion nanoparticles (UCNPs) and graphene oxide (GO) for CEA detection. The CEA aptamer modified UCNPs can bind to the surface of GO through π-π stacking interaction, resulting in fluorescence quenching due to the energy transfer from UCNPs to GO. After the introduction of CEA, the CEA aptamer preferentially combined with CEA to form three-dimensional structure which made UCNPs-aptamer dissociate from the GO, blocking the energy transfer process. The fluorescence of UCNPs was accordingly restored in a CEA concentration-dependent manner both aqueous solution and human serum samples. The aptasensor could monitor CEA level directly in human serum and the results were strongly correlated with commercial chemiluminescence kits. The excellent detection performance suggested promising prospect of the aptasensor in practical application.

Light curable dental composites designed with colloidal crystal reinforcement.

OBJECTIVES: Methods to prepare dental composites with a periodic filler arrangement were developed following a strategy of colloidal crystallization. The aims of this study were to determine the influence of suspension medium, silane treatment and amine additive on colloidal particle redispersion and subsequent ordering, and to evaluate the effect of filler ordering on mechanical properties of composites. METHODS: Dry monodisperse silica particles (spherical, approximately 500-nm diameter) were redispersed in selected solvents and monomers (e.g. triethyleneglycol dimethacrylate, TEGDMA) to form sediments or dispersions with ordered particle arrangements. Ordering was evaluated by microscopy and mechanical properties of the composites were measured using compression tests (n=6). RESULTS: A face-centered cubic packed structure could form in both the sediment from silica dispersions in polar solvents and stable dispersions in TEGDMA. Dimethylaminoethyl methacrylate (DMAEMA) was found to disrupt an ordered structure when non-silanized silica particles were used. Silanization with 3-methacryloxypropyl trimethoxysilane (MPS) promoted filler ordering. Standard compression tests on composites containing 60wt% silica in TEGDMA with or without DMAEMA indicated that DMAEMA had a clearly significant effect (p<0.05) on failure strain, compressive strength, and toughness, and a marginally significant effect on modulus (p=0.12). SIGNIFICANCE: Significant increases in compressive strength (16%), failure strain (71%), and toughness (135%) were observed for composites with ordered filler compared to non-ordered composites.