Search

Wastewater treatment plants are suspected to be significant point sources of microplastic and nanoplastic particles (NPs) in the environment. As one of the main wastewater treatment processes, advanced oxidation processes (AOPs) may change the physicochemical properties of NPs and further affect their migration. However, limited information is known about the environmental fate of NPs after AOP treatment. In this study, polystyrene nanoparticles were treated using two representative AOPs, Fenton and persulfate treatments, and the migration of the NPs in quartz sand was investigated via column transport experiments. FTIR and XPS analysis indicated that a large number of oxygen-containing groups were generated on the NP surface after AOP treatment leading to lower hydrophobicity and a higher negative charge. Besides, the C/O ratio after Fenton and persulfate treatments was increased from 10.98 to 7.25 and 8.68. Moreover, the NPs after AOP treatment exhibited higher mobility in quartz sand in both ultrapure water and 10 mM NaCl solution. It was more obvious in 10 mM NaCl solution with breakthrough percentages of 79.73% for P-PS, 90.97% for F-PS and 95.67% for N-PS, respectively. These results could be explained by the roles of generated oxygen-containing functional groups; first, the higher negative charge enhanced the electrostatic repulsion between treated NPs and sand; second, lower hydrophobicity improved the binding with water molecules in background solution. This work is helpful in understanding the changes of nanoplastics in AOP treatment and their migration in the natural environment, which has far-reaching influence on the environmental fate and behavior of nanoplastics.

With the wide application of dynamic compaction, its impact on surrounding buildings has received more and more attention. This paper established a numerical model for dynamic compaction and compared its results with actual experimental data to verify the effectiveness of the model. And the numerical results showed that the vibration isolation trench had an efficient vibration isolation effect during the dynamic compaction process. The study also found that the vibration isolation effect is determined by the width and depth of the vibration isolation trench, and the depth was more sensitive to the final effect. Therefore, this study can provide a theoretical basis for the design of vibration isolation trenches.

In this study, the removal performance for rhodamine B (RB) by persulfate (PS) activated by the CuFe2O4 catalyst in a heterogeneous catalytic system under LED light irradiation was investigated. The effect of vital experimental factors, including initial solution pH, CuFe2O4 dosage, PS concentration, co-existing anion and initial RB concentration on the removal of RB was systematically studied. The removal of RB was in accordance with the pseudo first-order reaction kinetics. Over 96% of 20 mg L−1 RB was removed in 60 min using 0.5 g L−1 CuFe2O4 catalyst and 0.2 mM PS at neutral pH. In addition, free radical quenching experiments and electron spin resonance (EPR) experiments were performed, which demonstrated the dominant role of sulfate radical, photogenerated holes and superoxide radical in the CuFe2O4/PS/LED system. The morphology and physicochemical properties of the catalyst were characterized by XRD, SEM-EDS, TEM, N2 adsorption–desorption isotherm, UV-vis DRS, and XPS measurements. Moreover, 18.23% and 38.79% total organic carbon (TOC) removal efficiency was reached in 30 min and 60 min, respectively. The catalyst revealed good performance during the reusability experiments with limited iron and copper leaching. Eventually, the major intermediates in the reaction were detected by GC/MS, and the possible photocatalytic pathway for the degradation of RB in the CuFe2O4/PS/LED system was proposed. The results suggest that the CuFe2O4/PS/LED system has good application for further wastewater treatment.

An efficient protocol has been developed for the cobalt-catalyzed perfluoroalkylation of 8-aminoquinoline scaffolds. In the presence of 5 mol% of Co(acac)3 catalyst, the desired products were obtained with exclusive substitution at the C5 position of the quinoline ring after 4 hours. The reaction shows high efficiency and good tolerance for a broad range of functional groups, affording the corresponding products in moderate to good yields.

The residues of tetracycline in environment have raised increasing concern for the deleterious impact on ecological and human health. Natural organic matter (NOM), ubiquitous in natural waters, is unavoidable to encounter tetracycline, which might affect the fate of tetracycline in aquatic environment. In this study, we investigated the effect of natural organic matter (NOM) on the photolytic fate of tetracycline (TC). The photolysis kinetics of TC were evaluated with two representative NOM, tannic acid (TA) and gallic acid (GA). The presence of TA and GA obviously inhibited the removal of TC under UV irradiation with photolysis rate constant at 0.067 h−1 and 0.071 h−1, respectively, which were 32.3% and 28.3% less than that without TA and GA (0.099 h−1). Furthermore, NOM exhibited different impacts on both indirect photolysis and direct photolysis. NOM promoted the formation of hydroxyl radical, induced the generation of triplet-excited state NOM and thus greatly enhanced the indirect photolysis of TC. However, direct photolysis was almost completely inhibited by NOM via inner filter effect and interacting with TC to form ground-state complex with low photoreactive. Moreover, similar intermediates were detected in the presence and absence of NOM, indicating that NOM exhibited limited influence on the degradation pathways of TC. This study reveals the multiple roles of NOM on tetracycline photolysis, contributing to better understand the photolytic fate of antibiotics in natural waters.

In this research, Fe-doped BiOCl nanosheets were successfully synthesized through controlled hydrothermal method and applied in the degradation of levofloxacin (LVX) by sulfate radical-based photo-Fenton process. The conduction band of Fe-doped BiOCl was calculated as 2.77 eV compared to BiOCl (3.24 eV), and showed remarkable visible-LED-light driven photocatalytic activity with the expanded visible light absorption. Certain parameters were studied, with the addition persulfate (1 mM) and catalyst dosage (0.5 g L−1) at natural pH, the LVX reached over 95% degradation efficiency in 60 min during at least five successive experiments which displayed excellent catalytic activity and stability. LVX degradation was confirmed to depend on the formation of free reactive oxidant species through radical scavenger reagents and EPR analysis. On the basis of the experimental results and density functional theory calculations, the role of photocatalytic degradation mechanism of LVX degradation by the Fe-BiOCl sample was investigated. Moreover, the LVX degradation pathway was induced according to the intermediates detected by LC-MS. The results of this research demonstrated the good feasibility of Fe-doped BiOCl nanosheets which would enhance the utilization of photocatalysts under visible light irradiation.

Diamondback moth, Plutella xylostella L., is a very important pest of cruciferous vegetables causing excessive economic losses worldwide. Bioactivities of halo-, diazo-, and cyclopropane acetates of P. xylostella sex pheromone have been evaluated using electrophysiology and enzyme inhibition assays.A total of 23 sex pheromone analogs of P. xylostella were designed and synthesized and the result shows that (11Z)-hexadec-11-en-1-yl 2,2,2-trifluoroacetate, (11Z)-hexadec-11-en-1-yl 2,2,3,3,3-pentafluoropropanoate, and (11Z)-hexadec-11-en-1-yl trifluoromethanesulfonate elicited potential inhibitory effects at all doses tested in the electrophysiology and enzyme inhibition assays. Interference of locating the sex pheromone source was found strongest when these three analogs were mixed with the sex pheromone at a 10:1 ratio. In addition, field test showed that the rate of mating disruption was over 90% when (11Z)-hexadec-11-en-1-yl 2,2,2-trifluoroacetate or (11Z)-hexadec-11-en-1-yl 2,2,3,3,3-pentafluoropropanoate was mixed with the sex pheromone at a 10:1 ratio.Two sex pheromone antagonists were screen out by electrophysiology, enzyme inhibition assays, wind tunnel and field tests. We believe that these antagonists could be used to establish a novel eco-friendly measure to control P. xylostella and provide evidence for clarifying the specific functions and molecular mechanisms of sex pheromone antagonists. © 2018 Society of Chemical Industry.

Multiple aspects of the transformed phenotype induced in a murine mammary epithelial cell line scp-2 by expression of activated G22V M-Ras, including maintainance of cell number at low density, anchorage-independent growth, invasion of Matrigel, and secretion of matrix metalloproteinases (MMP) 2 and 9, were dependent on an autocrine mechanism. Conditioned medium from dense cultures of scp-2 cells expressing G22V M-Ras, but not from parental cells, induced activation of Erk and Akt in cells expressing G22V M-Ras, maintained the cell number and promoted anchorage-independent growth of cells expressing G22V M-Ras (although not the parental cells), and induced scattering of MDCK cells. The latter activities were blocked by neutralizing antibodies to hepatocyte growth factor/scatter factor (HGF/SF) and could be mimicked by HGF/SF. Anti-HGF/SF antibodies also inhibited invasion of Matrigel, and the production of MMP-2 and MMP-9, together with urokinase-type plasminogen activator, was secreted by G22V M-Ras scp-2 cells but not by parental cells. Invasion of Matrigel was blocked by an inhibitor of MMPs, BB94, and by the mitogen-activated protein kinase kinase 1/2 kinase inhibitor PD98059 but was only marginally affected by the phosphatidylinositol 3-kinase inhibitor LY294002. Autocrine HGF/SF was thus critical for expression of key features of the phenotype of mammary epithelial cells transformed by expression of activated M-Ras.

We purified from activated T lymphocytes a novel, highly conserved, 116-kDa, intracellular protein that occurred at high levels in the large, dividing cells of the thymus, was up-regulated when resting T or B lymphocytes or hemopoietic progenitors were activated, and was down-regulated when a monocytic leukemia, M1, was induced to differentiate. Expression of the protein was highest in the thymus and spleen and lowest in tissues with a low proportion of dividing cells such as kidney or muscle, although expression was high in the brain. The protein was localized to the cytosol and was phosphorylated, which is consistent with a previous report that the Xenopus laevis ortholog was phosphorylated by a mitotically activated kinase (1 ). The cDNA was previously mischaracterized as encoding p137, a 137-kDa GPI-linked membrane protein (2 ). We propose that the authentic protein encoded by this cDNA be called cytoplasmic activation/proliferation-associated protein-1 (caprin-1), and show that it is the prototype of a novel family of proteins characterized by two novel protein domains, termed homology regions-1 and -2 (HR-1, HR-2). Although we have found evidence for caprins only in urochordates and vertebrates, two insect proteins exhibit well-conserved HR-1 domains. The HR-1 and HR-2 domains have no known function, although the HR-1 of caprin-1 appeared necessary for formation of multimeric complexes of caprin-1. Overexpression of a fusion protein of enhanced green fluorescent protein and caprin-1 induced a specific, dose-dependent suppression of the proliferation of NIH-3T3 cells, consistent with the notion that caprin-1 plays a role in cellular activation or proliferation.

The expression of activated mutants of M-Ras (G22V or Q71L), but not wild-type M-Ras, in a murine mammary epithelial cell line, scp2, resulted in epithelial-mesenchymal transition (EMT) and oncogenic transformation. Cells expressing constitutively active M-Ras continued to grow in the absence of serum and exhibited a loss of the epithelial markers cytokeratin, E-cadherin and beta-catenin, together with a gain of the mesenchymal marker vimentin, a loss of contact inhibition in monolayer growth and a gain of the capacity for anchorage-independent growth. Moreover, unlike the parental cells, they failed to form differentiated mammospheres on Matrigel and instead formed branched networks of cells that grew and invaded the Matrigel. The expression of activated p21 Ras (G12V H-Ras or Q61K N-Ras) also resulted in EMT and tumorigenesis, although there was evidence that expression of higher levels was toxic. Tumors derived from scp2 cells expressing activated M-Ras exhibited activation of Akt and of ERK. The levels of expression of Q71L M-Ras and G12V H-Ras required for tumorigenesis were comparable, although higher levels of the weaker G22V M-Ras mutant were selected for in vivo. These data indicate that the expression of activated mutants of M-Ras was sufficient for oncogenic transformation of a murine mammary epithelial cell line.

Cricopharyngeal myotomy is not effective in all cases of dysphagia. However, it should be the specific treatment in cases of dysphagia caused by a primary cricopharyngeal muscle dysfunction. Of a group of 10 patients with swallowing disorders in the absence of any defined cause, 7 (mean age, 81.6 years) were improved by a myotomy and 3 were not. The cricopharyngeal muscle was studied histologically and biochemically and compared to muscle obtained from nondysphagic subjects. In the muscle of the 7 improved patients, homogeneous histologic abnormalities were demonstrated: connective tissue infiltration, inflammatory cell infiltration, and degenerative changes of the muscle fibers. Conversely, muscles of the nonimproved patients and of the controls did not present the same degree of histologic lesions.