Environmental transformation and hazards of decachlorobiphenyl on suspended particles under sunlight irradiation.

Decachlorobiphenyl (PCB-209) can be widely detected in suspended particles and sediments due to its large hydrophobicity, and some of its transformation products may potentially threaten organisms through the food chain. Here we investigate the photochemical transformation of PCB-209 on suspended particles from the Yellow River. It was found that the suspended particles had an obvious shielding effect to largely inhibit the photodegradation of PCB-209. Meanwhile, the presence of inorganic ions (e.g. Mg2+ and NO3-) and organic matters (e.g. humic acid, HA) in the Yellow River water inhibited the reaction. The main transformation products of PCB-209 were lower-chlorinated and hydroxylated polychlorinated biphenyls (OH-PCBs), and small amounts of pentachlorophenol (PCP) and polychlorinated dibenzofurans (PCDFs) were also observed. The mechanisms of PCP formation by double •OH attacking carbon bridge and PCDFs formation by elimination reaction of ionic state OH-PCBs were proposed using theoretical calculations, which provided some new insights into the inter-transformations between persistent organic pollutants. In combination with VEGA and EPI Suite software, some intermediates such as PCDFs were more toxic to organisms than PCB-209. This study deepens the understanding of the transformation behavior of PCB-209 on suspended particles under sunlight.

Enhanced permanganate oxidation of phenolic pollutants by alumina and potential industrial application.

In this study, we found that alumina (Al2O3) may improve the degradation of phenolic pollutants by KMnO4 oxidation. In KMnO4/Al2O3 system, the removal efficiency of 2,4-Dibromophenol (2,4-DBP) was increased by 26.5%, and the apparent activation energy was decreased from 44.5 kJ/mol to 30.9 kJ/mol. The mechanism of Al2O3-catalytic was elucidated by electrochemical processes, X-ray photoelectron spectroscopy (XPS) characterization and theoretical analysis that the oxidation potential of MnO4- was improved from 0.46 V to 0.49 V. The improvement was attributed to the formation of coordination bonds between the O atoms in MnO4- and the empty P orbitals of the Al atoms in Al2O3 crystal leading to the even-more electron deficient state of MnO4-. The excellent reusability of Al2O3, the good performance on degradation of 2,4-DBP in real water, the satisfactory degradation of fixed-bed reactor, and the enhanced removal of 6 other phenolic pollutants demonstrated that the KMnO4/Al2O3 system has satisfactory potential industrial application value. This study offers evidence for the improvement of highly-efficient MnO4- oxidation systems.

Assessment of the UV/DCCNa and UV/NaClO oxidation process for the removal of diethyl phthalate (DEP) in the aqueous system.

In this work, the removal and transformation process of diethyl phthalate (DEP) in UV/dichloroisocyanurate (UV/DCCNa) and UV/sodium hypochlorite (UV/NaClO) systems were compared to evaluate the application potential of UV/DCCNa technology. Compared with UV/NaClO, UV/DCCNa process has the advantage of DEP removal and caused a higher degradation efficiency (93.8%) within 45 min of oxidation in ultrapure water due to the sustained release of hypochloric acid (HOCl). Fourteen intermediate products were found by high-resolution mass spectrometry, and the transformation patterns including hydroxylation, hydrolysis, chlorination, cross-coupling, and nitrosation were proposed. The oxidation processes were also performed under quasi-realistic environmental conditions, and it was found that DEP could be effectively removed in both systems, with yields of disinfection byproduct meeting the drinking water disinfection standard (<60.0 µg/L). Comparing the single system, the removal of DEP decreased in the mixed system containing five kinds of PAEs, which could be attributed to the regeneration of DEP and the competitive effect of •OH occurred among the Dimethyl phthalate (DMP), DEP, Dipropyl phthalate (DPrP), Diallyl phthalate (DAP) and Diisobutyl phthalate (DiBP). However, a greater removal performance presented in UV/DCCNa system compared with UV/NaClO system (69.4% > 62.1%). Further, assessment of mutagenicity and developmental toxicity by Toxicity Estimation Software Tool (T.E.S.T) software indicated that UV/DCCNa process has fewer adverse effects on the environment and is a more environmentally friendly chlorination method. This study may provide some guidance for selecting the suitable disinfection technology for drinking water treatment.

Enhanced removal of bisphenol S in ozone/peroxymonosulfate system: Kinetics, intermediates and reaction mechanism.

The degradation process of bisphenol S (BPS) in ozone/peroxymonosulfate (O3/PMS) system was systematically explored. The results showed that the removal efficiency of BPS by O3 could be significantly improved with addition of PMS. Compared with ozonation alone, the pseudo-first-order constant (kobs) was increased by 2-5 times after adding 400 µM PMS. In O3/PMS system, accelerated removal of BPS was observed under neutral and alkaline conditions. The removal efficiency of BPS reached 100% after 40 s of reaction at pH 7.0, with the kobs of 0.098 s-1. Moreover, Cu2+ had a catalytic effect on the O3/PMS system, because it could catalyze the decomposition of ozone and PMS to produce •OH and SO4•-, respectively. Electron paramagnetic resonance illustrated that •OH and SO4•- were the reactive species in O3/PMS system. Twelve intermediates were identified by mass spectrometry, and the degradation reactions in O3/PMS system mainly included hydroxylation, sulfate addition, polymerization and ß-scission. Finally, the toxicity of the products was evaluated by the EOCSAR program. Our results introduce an efficient method for BPS removal and would provide some guidance for the development of O3-based advanced oxidation technology.

A Study on the Acquisition and Identification of Beige Adipocytes and Exosomes as Well as Their Inflammatory Regulation by Promoting Macrophage Polarization.

BACKGROUND: The fat retention rate is associated with postoperative inflammation. However, fat survival is still unpredictable even when supplemented with adipose-derived stem cells (ADSCs). Beige adipocytes play a role in regulating pathological inflammation. Thus, we assumed that exosomes may promote macrophage polarization to regulate inflammation when we simulated postgrafted inflammation by lipopolysaccharide (LPS) induction. METHODS: 3T3-L1 preadipocytes were used to differentiate into beige adipocytes, which were stimulated by special culture media, and then, exosomes were isolated from the supernatant. We identified them by morphology, protein and gene expression, or size distribution. Next, we utilized exosomes to stimulate LPS-induced macrophages and evaluated the changes in inflammatory cytokines and macrophage polarization. RESULTS: The induced cells contained multilocular lipid droplets and expressed uncoupling protein 1 (UCP1) and beige adipocyte-specific gene. The exosomes, which were approximately 111.5 nm and cup-like, were positive for surface markers. Additionally, the levels of proinflammatory-related indicators in the LPS+exosomes (LPS+Exos) group were increased after inflammation was activated for 6 h. When inflammation lasted 16 h, exosomes decreased the expression of proinflammatory-related indicators and increased the expression of anti-inflammatory-related indicators compared with the group without exosomes. CONCLUSION: The method described in this article can successfully obtain beige adipocytes and exosomes. The results suggest that beige adipocyte exosomes can promote inflammatory infiltration and polarize more macrophages to the M1 type in the early period of inflammation, accelerating the occurrence of the inflammation endpoint and the progression of macrophage switching from M1 to M2, while inflammation develops continuously. NO LEVEL ASSIGNED: This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Insights into oxidation of pentachlorophenol (PCP) by low-dose ferrate(VI) catalyzed with α-Fe2O3 nanoparticles.

In this study, the catalytic performance of α-Fe2O3 nanoparticles (nα-Fe2O3) in the low-dose ferrate (Fe(VI)) system was systematically studied through the degradation of pentachlorophenol (PCP). Based on the established quadratic functions between nα-Fe2O3 amount and observed pseudo first-order rate constant (kobs), two linear correlation equations were offered to predict the optimum catalyst dosage and the maximum kobs at an applied Fe(VI) amount. Moreover, characterization and cycling experiments showed that nα-Fe2O3 has good stability and recyclability. According to the results of reactive species identification and quenching experiment and galvanic oxidation process, the catalytic mechanism was proposed that Fe(III) on the surface of nα-Fe2O3 may react with Fe(VI) to enhance the generation of highly reactive Fe(IV)/Fe(V) species, which rapidly extracted a single electron from PCP molecule for its further reaction. Besides, two possible PCP degradation pathways, i.e., single oxygen transfer mediated hydroxylation and single electron transfer initiated polymerization were proposed. The formation of coupling products that are prone to precipition and separation was largely improved. This study proved that nα-Fe2O3 can effectively catalyze PCP removal at low-dose Fe(VI), which provides some support for the application of Fe(VI) oxidation technology in water treatment in the context of low-carbon emissions.

Comparative studies of transformation behaviors and mechanisms of halophenols in multiple chemical oxidative systems.

Due to wide applications, halophenols (HPs), especially bromophenols, chlorophenols, and fluorophenols, are commonly detected but resistant to biological removal in wastewater treatment plants (WWTPs). This study investigated the overall transformation behaviors of three representative HPs (2,4-dichlorophenol: 24-DCP, 2,4-dibromophenol: 24-DBP, 2,4-difluorophenol: 24-DFP) in six chemical oxidative systems (KMnO4, K2FeO4, NaClO, O3, UV, and persulfate (PS)). The results revealed fast removal of selected HPs by O3, PS and K2FeO4, while a large discrepancy in their removal efficiencies occurred under UV irradiation, KMnO4 oxidation and particularly chlorination. Based on the analysis of the identified intermediates and products, coupling among the five routes was the general route, and dimers were the main intermediates for HP oxidation. The effect of the halogen atom on the transformation pathways of HPs was highly reaction type dependent. Among the six chemical treatments, PS could induce HPs to yield relatively low-molecular-weight polymers and obtain the highest coupling degree. Transition state (TS) calculations showed that the H atom linked to the phenoxy group of HPs was the most easily abstracted by hydroxyl radicals to form the coupling precursor, i.e., phenoxy radicals. This high coupling behavior further resulted in the increased toxicity to green algae. Characterization revealed that HP reaction solutions treated with PS had a severely negative effect on algae growth, photosynthetic pigment synthesis, and the antioxidant enzyme system. These findings can shed light on the reaction mechanisms of advanced oxidation technologies and some risk management and control of PS technique may be considered when treating phenolic pollutants.

Scratching your tête over language-switched idioms: Evidence from eye-movement measures of reading.

Idioms are semantically non-compositional multiword units whose meanings often go beyond literal interpretations of their component words (e.g., break the ice, kick the bucket, spill the beans). According to hybrid models of idiom processing, idioms are subject to both direct retrieval from the lexicon in early stages of processing, and word-by-word compositional reanalysis in later stages of comprehension. However, a less clear aspect is how disrupting an idiom's canonical form, and thus its direct retrieval, impacts the time course of comprehension. In this eye-tracking reading study, healthy English-French bilingual adults with English as their dominant language read sentences containing English idioms in their canonical form (e.g., break the ice), or in a switched form where the phrase-final noun was translated into French (e.g., break the glace). Thus, within this manipulation, momentary language switches modified the canonical form of idioms, while at the same time minimally altering the semantics of their component words, thus nudging readers towards a compositional processing route. Analyses of eye-movement data revealed switching costs in longer reading times at early (but not late) processing stages for idioms compared to matched literal phrases. Interestingly, the cost of language switching was attenuated by the availability of a translationally equivalent idiom in the non-target language (French, e.g., briser la glace). Taken together, these results suggest that direct retrieval is the preferential route in the comprehension of idioms' canonical forms, which acts as an effective repair strategy by the language-processing system when recovering the underlying form of modified idioms.

Critical analysis of peptidoglycan structure of Lactobacillus acidophilus for phthalate removal.

Our previous studies have shown that lactic acid bacteria (LABs) can bind and remove di-n-butyl phthalate (DBP), diethyl phthalate, and dioctyl phthalate; three ubiquitous environmental phthalate contaminants. In this study, Lactobacillus acidophilus NCFM was chosen to study the DBP binding mechanism. We found that the three-dimensional structure of the bacterial cell wall, including the carbohydrates and proteins, was essential for DBP adsorption. Peptidoglycan was the main binding component in the cell wall (80.71%), and binding sites exposed to DBP were C-N, N-H, O-H, and C-O bonds. Molecular dynamic (MD) studies demonstrated that hydrophobic interaction plays an important role in DBP adsorption, the chemical sites that influenced the binding in the peptidoglycan model were O2, O3>N1, N2, N3>O1, O4, and the form of adsorption force included hydrogen bonding force, electrostatic force, and van der Waals forces. These theoretical data from the MD simulation were consistent with the experimental results in terms of the ability of this bacterium to bind DBP, so the MD simulation proposed a new way to investigate the mechanisms of phthalate binding to LABs.

Products distribution and contribution of (de)chlorination, hydroxylation and coupling reactions to 2,4-dichlorophenol removal in seven oxidation systems.

We systemically investigated the transformation behavior of 2,4-dichlorophenol (24-DCP) in seven different reaction systems including KMnO4, heat/PS, O3, UV, Fenton, NaClO and K2FeO4 treatment. The results revealed that complete removal of 24-DCP could be reached in minutes, especially for Fe(VI), KMnO4, NaClO, Fenton and O3 system. A total of 41 products were identified by LC-MS, and 10 of them were validated using commercial and self-synthesized standards. Hydroxyl substitution and coupling reactions were commonly observed in the studied systems. Meanwhile, extra routes such as sulfate substitution, (de)chlorination and direct oxidation were also involved for certain oxidation methods. Comparisons showed that a high degree of chlorination (>90%) occurred for NaClO system, while coupling products accounted for ~45% of the removed 24-DCP under PS oxidation. Moreover, low mineralization degree together with high aquatic toxicity was attributed to the occurrence of coupling reaction, which was possibly related to the redox potential of the main oxidative species. Considering the low abundance of coupling products and the gentle reaction condition, UV irradiation is a better option for 24-DCP removal in water and wastewaters. These findings can deepen our understanding on the transformation process of 24-DCP and provide some useful information for the environmental elimination of substituted phenols.

KMnO4-mediated reactions for hexachlorophene in aqueous solutions: Direct oxidation, self-coupling, and cross-coupling.

Hexachlorophene (HCP) is used in a range of general cleaning and disinfecting products and has received increased attention due to its damaging effect to the central nervous system in animals and its toxicity in humans. The chemical oxidation of HCP by KMnO4 was performed to systematically evaluate the effects of oxidant dose, pH, temperature, typical anions, humic acid (HA), and various matrices on HCP removal. The second-order rate constant for HCP was determined to be 4.83 × 104 M-1 s-1 at pH 7.0 and 25 °C. The presence of HA can inhibit the removal of HCP by KMnO4, while Cl-, NO3-, SO42-, PO43-, and CO32- have negligible effects. Degradation products analysis of the reaction, as well as theoretical calculations of HCP molecule and its phenoxy radical species, indicated that KMnO4 oxidation for HCP included a C-C bridge bond cleavage, hydroxylation, direct oxidation and self-coupling, and cross-coupling reactions. This study revealed that KMnO4 oxidation is an effective technique for eliminating HCP in real water and wastewater.

Alumina-mediated photocatalytic degradation of hexachlorobenzene in aqueous system: Kinetics and mechanism.

Five kinds of Al2O3 were characterized by SEM, TEM, FT-IR and BET surface area, and then used as carriers to investigate the photochemical removal of hexachlorobenzene (HCB) in aqueous system. The results showed that HCB coated on the surfaces of all Al2O3 could be photodegraded rapidly, and Neutral-Al2O3 presented the best performance. Meanwhile, the efficient removal of HCB in real water matrices, including tap water, river water and secondary clarifier effluent showed the potential practical application of Al2O3. EPR and theoretical calculation revealed the generation of hydroxyl radicals on Al2O3 surface under 500 W Xe lamp irradiation. Nine intermediates and a small amount of Cl- were identified by GC/MS, LC/MS and IC analysis, which was further verified by transition state calculations. These results can provide a new technique for HCB removal in water and wastewaters, and give more insights into the environmental ecological risk assessment of this pollutant.

Examining the Functional Category in Chinese-English Code-Switching: Evidence from the Eye-Movements.

To investigate the grammatical constraints of code-switching (CS hereafter) under the disputes of the constraint-based account versus the constraint-free account, the effects of functional category on CS have long been investigated in the existing studies. Thus, the present study, by asking 47 participants to take part in an eye-movement experiment, examined the potential effects of functional category on Chinese-English CS. We found that differential switch costs at varying code-switched conditions as well as robust switch effects that last from the early to the late stage. The findings could tentatively give rise to the theoretical predictions of the minimalist program, a representative of the constraint-free account rather than the functional head constraint, a typical representative of the constraint-based account. Moreover, such switch effects might initiate from the early to the very late stage in terms of time-course of CS processing.

Berberine inhibits Chlamydia pneumoniae infection-induced vascular smooth muscle cell migration through downregulating MMP3 and MMP9 via PI3K.

The mechanisms by which Chlamydia pneumoniae infection promote vascular smooth muscle cell (VSMC) migration required in the development of atherosclerosis have not yet been fully clarified. Matrix metalloproteinases (MMPs) have important roles in VSMC migration. However, it is still unknown whether MMPs are involved in C. pneumoniae infection-induced VSMC migration. In addition, whether berberine can exert its inhibitory effects on the infection-induced VSMC migration also remains unclear. Accordingly, we investigated the effects of berberine on C. pneumoniae infection-induced VSMC migration and explored the possible mechanisms involved in this process. Herein, we found that C. pneumoniae infection could induce VSMC migration through Matrigel-coated membrane (P<0.05), which can be significantly inhibited by the broad-spectrum MMP inhibitor GM6001 (P<0.05). Our results also showed that C. pneumoniae infection upregulated both mRNA and protein expressions of MMP3 and MMP9 (P<0.05). The specific phosphoinositide 3-kinase (PI3K) inhibitor LY294002 significantly suppressed the increases in MMP3 and MMP9 protein expressions induced by C. pneumoniae infection (P<0.05). Further experiments showed that berberine significantly attenuated C. pneumoniae infection-induced VSMC migration (P<0.05). Moreover, berberine suppressed the protein expressions of MMP3 and MMP9 caused by C. pneumoniae infection in a dose-dependent manner (P<0.05). C. pneumoniae infection-induced increase in the phosphorylation level of Akt at Ser473 was inhibited by the treatment with berberine (P<0.05). Taken together, our data suggest that berberine inhibits C. pneumoniae infection-induced VSMC migration by downregulating the expressions of MMP3 and MMP9 via PI3K.

Chlamydia pneumoniae infection induces vascular smooth muscle cell migration via Rac1 activation.

Chlamydia pneumoniae infection has been shown to be associated with the development of atherosclerosis by promoting the migration of vascular smooth muscle cells (VSMCs). However, how C. pneumoniae infection induces VSMC migration is not fully understood. A primary role of Ras-related C3 botulinum toxin substrate 1 (Rac1) is to generate a protrusive force at the leading edge that contributes to cell migration. Whether Rac1 activation plays a role in C. pneumoniae infection-induced VSMC migration is not well defined. In the present study, we therefore examined Rac1 activation in C. pneumoniae-infected rat primary VSMCs and the role of Rac1 activation in C. pneumoniae infection-induced VSMC migration. Glutathione S-transferase pull-down assay results showed that Rac1 was activated in C. pneumoniae-infected rat primary VSMCs. A Rac1 inhibitor, NSC23766 (50 µM,) suppressed Rac1 activation stimulated by C. pneumoniae infection, and thereby inhibited C. pneumoniae infection-induced VSMC migration. In addition, C. pneumoniae infection-induced Rac1 activation in the VSMCs was blocked by LY294002 (25 µM), an inhibitor of phosphatidylinositol 3-kinase (PI3K). Taken together, these data suggest that C. pneumoniae infection promotes VSMC migration, possibly through activating Rac1 via PI3K.

Chlamydia pneumoniae infection promotes vascular smooth muscle cell migration through a Toll-like receptor 2-related signaling pathway.

The migration of vascular smooth muscle cells (VSMCs) from the media to the intima is proposed to be a key event in the development of atherosclerosis. Recently, we reported that Chlamydia pneumoniae infection is involved in VSMC migration. However, the exact mechanisms for C. pneumoniae infection-induced VSMC migration are not yet well elucidated. In this study, we examined the role of the Toll-like receptor 2 (TLR2) activation-related signaling pathway in VSMC migration induced by C. pneumoniae infection. An Affymetrix-based gene expression array was conducted to identify the changes of gene expression in rat primary VSMCs (rVSMCs) infected with C. pneumoniae. Both the microarray analysis and quantitative real-time reverse transcription (RT)-PCR revealed that TLR2 mRNA expression was strongly upregulated 12 h after C. pneumoniae infection. RT-PCR and Western blot analysis further showed that the expression levels of TLR2 mRNA and protein significantly increased at the different time points after infection. Immunocytochemical analysis suggested a TLR2 recruitment to the vicinity of C. pneumoniae inclusions. Cell migration assays showed that the TLR2-neutralizing antibody could significantly inhibit C. pneumoniae infection-induced rVSMC migration. In addition, C. pneumoniae infection stimulated Akt phosphorylation at Ser 473, which was obviously suppressed by the PI3K inhibitor LY294002, thereby inhibiting rVSMC migration caused by C. pneumoniae infection. Furthermore, both the infection-induced Akt phosphorylation and rVSMC migration were suppressed by the TLR2-neutralizing antibody. Taken together, these data suggest that C. pneumoniae infection can promote VSMC migration possibly through the TLR2-related signaling pathway.

[Role of LNK gene mutation in pathogenesis of myeloproliferative neoplasms-review].

Myeloproliferative neoplasms ( MPN ) is a class of clonal hematopoietic stem cell disease. Studies found that the JAK-STAT signaling pathway is closely related to the pathogenesis of MPN. The lymphocyte-specific adaptor protein (LNK) gene negatively regulates Janus kinase-signal transducer and activator of transcription (JAK-STAT) signaling and may play an important role in the pathogenesis of MPN. Especially in JAK2 mutation-negative MPN, LNK gene specific mutations may be the key to cause MPN subtypes. Certain single nucleotide polymorphism of LNK gene regulation of hematopoietic cells in different directions may also be important influence factors of MPN performance for different subtypes. LNK gene functional changes lead to abnormal activation of the JAK-STAT signaling pathway, and may be a new mechanism of MPN. In this review, the role of LNK gene in MPN pathogenesis is briefly summarized.