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Bi2+xWO6 is a cost-effective and environmentally friendly photocatalyst that shows high reactivity in the oxidation of various contaminants under visible light. However, under alkaline conditions, the reactive oxidative species in the Bi2+xWO6 system are still not clear yet. In this study, it is observed that the oxidation rates of As(III) increase with increasing pH values in the Bi2.15WO6 system. Photoluminescence and the Mott–Schottky analyses confirm that OH− promotes the separation and transfer of photogenerated electron–hole pairs over Bi2.15WO6, thus facilitating the oxidation of As(III). Electron spin resonance spectra analysis and quenching experiments rule out contributions of •OH, O2˙−, 1O2 and superoxo species to As(III) oxidation and indicate that surface –OOH and/or H2O2 are indeed the predominant species under alkaline conditions. The improved production of H2O2 by H-donors such as glucose and phenol, as well as the UV-vis diffuse reflectance and Raman analyses, further confirms the formation of surface –OOH on Bi2.15WO6 under alkaline conditions. In the dark, the significant higher oxidation rate of As(III) by H2O2–Bi2.15WO6 than that by H2O2 alone reveals that surface −OOH, instead of H2O2, plays an important role in As(III) oxidation. This study enriches our understanding of the diversity of reactive oxygen species (ROS) in the Bi2.15WO6 system and gives new insight into the mechanism involved in the oxidation of As(III) under alkaline conditions. [ABSTRACT FROM AUTHOR]

In this study, polyvinyl alcohol (PVA)-degrading bacteria were screened from oil sludge using PVA as a sole source of carbon in the culture medium. A novel strain, SA21, was obtained and identified as a member of the Stenotrophomonas genus based on the analysis of a partial 16S rDNA nucleotide sequence, morphological and biochemical characteristics, and phylogenetic analysis. This Stenotrophomonas isolate had not previously been reported as a PVA-degrading bacterium. Stenotrophomonas sp. strain SA21 degraded 90% of the PVA present in the culture medium after 4 days. The effect of nitrogen sources on the production of PVA-degrading enzyme involved in the biodegradation process was significant, and the enzymatic activity reached 82 U/ml when ammonium nitrate or urea was used in the optimized medium. The information obtained in this study will provide a foundation for improving industrial wastewater treatment. Abbreviations: DCW: dry cell weight; FTIR: Fourier Transform Infrared Spectroscopy; NCBI: National Center for Biotechnology Information; PCR: polymerase chain reaction; PVA: polyvinyl alcohol; SEM: scanning electron microscope [ABSTRACT FROM AUTHOR]

Bi2+xWO6 is a cost-effective and environmentally friendly photocatalyst that shows high reactivity in the oxidation of various contaminants under visible light. However, under alkaline conditions, the reactive oxidative species in the Bi2+xWO6 system are still not clear yet. In this study, it is observed that the oxidation rates of As(iii) increase with increasing pH values in the Bi2.15WO6 system. Photoluminescence and the Mott-Schottky analyses confirm that OH- promotes the separation and transfer of photogenerated electron-hole pairs over Bi2.15WO6, thus facilitating the oxidation of As(iii). Electron spin resonance spectra analysis and quenching experiments rule out contributions of •OH, O2˙-, 1O2 and superoxo species to As(iii) oxidation and indicate that surface -OOH and/or H2O2 are indeed the predominant species under alkaline conditions. The improved production of H2O2 by H-donors such as glucose and phenol, as well as the UV-vis diffuse reflectance and Raman analyses, further confirms the formation of surface -OOH on Bi2.15WO6 under alkaline conditions. In the dark, the significant higher oxidation rate of As(iii) by H2O2-Bi2.15WO6 than that by H2O2 alone reveals that surface -OOH, instead of H2O2, plays an important role in As(iii) oxidation. This study enriches our understanding of the diversity of reactive oxygen species (ROS) in the Bi2.15WO6 system and gives new insight into the mechanism involved in the oxidation of As(iii) under alkaline conditions.

The Mn II (HCO 3 - )-H 2 O 2 (Mn II -BAP) system shows high reactivity toward oxidation of electron-rich organic substrates; however, the predominant oxidizing species and its formation pathways involved in the Mn II -BAP system are still under debate. In this study, we used the Mn II -BAP system to oxidize As(III) in that As(III), Mn 2+ , and HCO 3 - are common components in As(III)-contaminated groundwater. Kinetic results show that Mn II (HCO 3 - ) n [including Mn II (HCO 3 ) + and Mn II (HCO 3 ) 2 ] is a key factor in the Mn II -BAP system to oxidize As(III). Quenching experiments rule out contributions of OH • and 1 O 2 to As(III) oxidation and reveal that O 2 •- and the oxidizing species generated from O 2 •- play predominant roles in the oxidation of As(III). We further reveal that the MnO 2 + (HCO 3 - ) n intermediate generated in the reaction between Mn II (HCO 3 - ) n and O 2 •- , instead of O 2 •- , is the predominant oxidizing species. Although CO 3 •- also contributes to As(III) oxidation, the high reaction rate constant between CO 3 •- and O 2 •- indicates that CO 3 •- is not the predominant oxidizing species in the As(III)-Mn II -BAP system. In addition, the presence of Mn(III) further indicates the important Mn(II)-Mn(III) cycling in the Mn II -BAP system. We therefore suggest two important roles of Mn II (HCO 3 - ) n in the Mn II -BAP system: (i) Mn II (HCO 3 - ) n reacts with H 2 O 2 to form the Mn III (HCO 3 ) 3 intermediate, followed by a subsequent reaction between Mn III (HCO 3 ) 3 and H 2 O 2 to produce O 2 •- ; (ii) Mn II (HCO 3 - ) n can also stabilize O 2 •- with the formation of MnO 2 + (HCO 3 - ) n . MnO 2 + (HCO 3 - ) n is an electrophilic reagent and plays the predominant role in the oxidation of As(III) to As(V).

Butein (3,4,2',4'-tetrahydroxychalcone) belongs to the chalcone family of flavonoids and possesses various biological activities. In this study, butein was synthesized through aldol condensation catalyzed by thionyl chloride (SOCl 2 )/ethyl alcohol (EtOH) for the first time. The optimal reaction conditions including the molar ratio of reactants, the dosage of catalyst, and the reaction time on the yield of product were investigated, and the straightforward strategy assembles the yield of butein up to 88%. Butein has been found to inhibit xanthine oxidase (XO) activity. Herein, the inhibitory mechanism of butein against XO was discussed in aspects of inhibition kinetic, fluorescence titration, synchronous fluorescence spectroscopy, and molecular docking. The inhibition kinetic analysis showed that butein possessed a stronger inhibition on XO in an irreversible competitive manner with IC 50 value of 2.93 × 10 -6 mol L -1 . The results of fluorescence titrations and synchronous fluorescence spectroscopy indicated that butein was able to interact with XO at one binding site, and the fluorophores of XO were placed in a more hydrophobic environment with the addition of butein. Subsequently, the result of molecular docking between butein and XO protein revealed that butein formed hydrogen bonding with the amino acid residues located in the hydrophobic cavity of XO. All the results suggested that the inhibitory mechanism of butein on XO may be the insertion of butein into the active site occupying the catalytic center of XO to avoid the entrance of xanthine and inducing conformational changes in XO.

Objective: To analyze clinical efficiency and intraoperative considerations of ankle arthroscopy for ankle impingement syndrome through anterior and posterior passage., Methods: From April 2011 to April 2015, the clinical data of 17 patients diagnosed as ankle impingement syndrome were performed arthroscopy, including 12 males and 5 females, with an average age of 32.4 years (ranging from 22 to 47). Ankle arthroscopy cleaning were carried out according to clinical symptoms and radiological imaging, crashed part were cleaned too. Non steroidal anti-inflammatory drugs and intra-articular injection of sodium hyaluronate were used as conventional postoperatively treatment. AOFAS score and Ogilvie-Harris score were used to assess preoperative situation and postoperative situation., Results: Intra-operative conditions showed 8 cases with anterior lateral impingement syndromes, 2 cases with anterior medial impingement syndromes, 2 cases with posterior impingement syndromes and 3 cases combined with anterior and posterior impingement syndromes. Distal bundle of anterior tibiofibular ligament, anterior talusfibular ligament and synovial tissue and scar tissue were cleared up during operation. Four patients were combined with concomitant articular cartilage injury, and damage area were about 1 mm×3 mm to 1.5 mm×4 mm. Microfracture treatment were performed by 1.2 mm diameter Kirschner wire. All patients were followed up from 8 to 24 months with an average of 14.3 months. AOFAS score increased from 62.3±5.20 preoperatively to 87.6±5.40 postoperatively, Ogilvie-Harris ankle score increased from 6.70±0.98 preoperatively to 12.80±1.21 postoperatively. No neurovascular damage, wound infection or wound healing problem occurred. Ankle swelling were appeared with different degrees, but disappeared at 4 to 8 weeks postoperatively., Conclusions: For ankle impingement syndrome patients, ankle arthroscopy through anterior with posterior passage could effectively clear up bone and soft tissue impingement. Postoperatively non-steroidal anti-inflammatory drugs and intra-articular injection of sodium hyaluronate could effectively relieve ankle pain and swollen and achieve good therapeutic effect., Competing Interests: The authors of this article and the planning committee members and staff have no relevant financial relationships with commercial interests to disclose.

WRKY transcription factors are novel transcriptional regulatory factors, which play an important role in regulating plant development, metabolism and other physiological processes. In this study, a new Dendrobium officinale WRKY transcription factor, designated as DoWRKY1 was cloned by using RT-PCR and RACE (GenBank Accession No. KF953910). Bioinformatic analysis demonstrated that, the full-length cDNA of DoWRKY1 was 1,704 bp. And DoWRKY1 contained a 1,629 bp open reading frame (ORF) that encoding a peptide of 542 amino acid residues. The putative DoWRKY1 protein contained two conserved WRKY domains and it belonged to the group I WRKY family protein. Yeast one-hybrid experiment showed that DoWRKY1 had transcriptional activation ability in yeast, and it could activate the expression of downstream report genes (His3 and Ade2). Semi-quantitative RT-PCR experiment showed that DoWRKY1 expressed in roots, stems, leaves and protocorm-like bodies. Real-time qRT-PCR proved that DoWRKY1 could be induced by methyl jasmonate (MeJA) and chitosan (Chitosan), and the expression level of this gene can reach the expression peak at 2 h and 1 h, respectively. These results are useful for further determination of the regulation function of this gene in secondary metabolism of D. officinale.