Enhanced sequestration of molybdenum(VI) using composite constructed wetlands and responses of microbial communities.

The molybdenum (Mo) non-point source pollution in the mining area has an irreversible impact on the surrounding water and soil ecosystems. Herein, three integrated vertical subsurface flow constructed wetlands (CWs) were constructed to assess the effects of combination substrates and plant on the removal of Mo(VI). Results showed that CW1 with combination substrates and cattail exhibited a favorable removal performance for Mo(VI) at 80.90%. Moreover, most Mo(VI) retained in the CWs was retained in the substrate (58.13-88.04%), and the largest fraction of Mo(VI) retained was the water-soluble fraction on the surface of the combination substrates. Mo(VI) removal was also influenced by the microbial community composition in substrate, especially their co-occurrence networks. The species that showed significant positive correlation with Mo(VI) removal were Planctomycetes, Latescibacteria, Armatimonadetes, and Gemmatimonadetes. Moreover, CWs added plants showed that more co-occurrences interaction between taxa occurs, which means that the wetlands efficiently select recruitment of potential microbial consortia and change the co-occurrences to remove pollution in the substrate. These results could be useful in providing an ecology-based solution for the treatment of Mo(VI) in wastewater, especially in adjusting the microbial communities for Mo(VI) removal at the genetic level.

Enhanced molybdenum(VI) removal using sulfide-modified nanoscale zerovalent iron: kinetics and influencing factors.

The overall goal of this study is to investigate the effect of sulfidated nanoscale zerovalent iron (S-nZVI) on the removal of hexavalent molybdate (MoO42-) under different aquatic chemistry conditions. Surface analysis suggests that Mo(VI) is removed mainly by adsorption and co-precipitation onto the surface of S-nZVI and a small amount of Mo(VI) can be reduced to Mo(V) species. The results of batch tests show that Mo(VI) removal by S-nZVI are well described with the pseudo-second-order adsorption model. The removal rate increases with a decrease in solution pH (4.0-9.0) and is significantly affected by the S/Fe ratio of S-nZVI, with the optimal S/Fe ratio being 0.5. The presence of anions WO42- or CrO42- can reduce the Mo(VI) removal, which is likely because they compete for adsorption sites on the solid surfaces. The divalent cations Ni2+, Cu2+ and Co2+ also inhibit the removal of Mo(VI) whereas Zn2+, Ca2+ and Mg2+ enhance it. After being aged for 35 d in water, S-nZVI still exhibits high reactivity towards Mo(VI) removal (57.39%). The study demonstrates that S-nZVI can be used as an environmentally friendly material for effectively removing Mo(VI) from contaminated water.

Removal of molybdenum(VI) from aqueous solutions using nano zero-valent iron supported on biochar enhanced by cetyl-trimethyl ammonium bromide: adsorption kinetic, isotherm and mechanism studies.

A new carbonized pomelo peel biosorbent (MCPP) modified with nanoscale zero-valent iron (NZVI) and cetyl-trimethyl ammonium bromide was prepared and employed for the adsorption of molybdate (Mo(VI)) from aqueous solution. We investigated the effects of various conditions on Mo(VI) adsorption and evaluated the results based on adsorption kinetics models and isotherm equations. The kinetic data fitted to the pseudo-second-order model. The Langmuir model best described the adsorption of Mo(VI) on MCPP. The values of changes in Gibbs free energy, standard enthalpy, and standard entropy revealed that the adsorption process was feasible, spontaneous and endothermal. X-ray diffraction, Fourier transform infrared and X-ray photoelectron spectroscopy measurements suggested that Mo(VI) adsorption occurred via both the reduction and surface adsorption. Thus, biochar, prepared from fruit residue, can be applied to remove Mo(VI) from aqueous solutions. More importantly, our results provide a sustainable approach for Mo(VI) removal from wastewater by means of functional modification.

High FoxP3 expression in tumour cells predicts better survival in gastric cancer and its role in tumour microenvironment.

BACKGROUND: Forkhead Box P3 (FoxP3) is thought to be a key transcription factor in regulatory T cells (Tregs), and recent data indicate that it is expressed in several tumour cells. However, its precise roles in gastric cancer (GC) and the underlying mechanisms regulating the interaction between GC cells and lymphocytes remain unclear. METHODS: FoxP3 expression was examined in tumour cells and Tregs in 150 cases of gastric precancer and cancer, and their prognostic significances were evaluated, respectively, using a tissue microarray containing 135 GC patient samples with a mean 102-month follow-up. FoxP3 involvement in the tumour cells-lymphocytes interaction and its gene function were further investigated. RESULTS: strong cytoplasmic staining of FoxP3 was observed in GC cells. FoxP3 protein expression in tumour cells predicts a good prognosis, whereas high-density Treg predicts a poor prognosis. Moreover, FoxP3 expression in GC cells increased after coculture with peripheral blood mononuclear cells through coculture systems. Upregulation of FoxP3 inhibited tumour growth in tumour-bearing nude mice. CONCLUSIONS: High FoxP3 expression in tumour cells predicts better survival in GC, possibility in relation to interaction between tumour cells and lymphocytes in microenvironment. Interfering with FoxP3 expression may open a new therapeutic strategy against tumour progression.

Molybdenum(VI) removal by using constructed wetlands with different filter media and plants.

The efficacy and capacity of vertical-flow wetland filters on molybdenum (Mo) removal from wastewater was examined, employing reed (Phragmites australis) and cattail (Typha latifolia) as well as different adsorption granular media. Humus, cinder, modified cinder, as well as pyrite were used as filter media. A synthetic effluent with different concentrations of Mo(VI) at different hydraulic retention times was used for simulating Mo leached mine wastewater. Laboratory experiments showed that the equilibrium adsorption data were in agreement with the Langmuir isotherm model, and the maximum Mo(VI) adsorption capacities of modified cinder and pyrite were 10.01 and 6.25 mg/g, respectively. Mo(VI) removal in F5 (combination substrates of pyrite and cinder) was found to be more stable and effective than that of F1 (conventional gravel and soil filter media) during the 14-week experiment. Most of the Mo(VI) was retained in the 10-20 cm of the substrate, and adsorbed by the modified cinder and pyrite. The largest fraction of Mo(VI) retained was the water-soluble fraction on the surface of the pyrite. Cattail was more suitable for Mo(VI) absorption than reed, but the bioaccumulation accounted for a very small portion of the total removal.

Effect of earthworm loads on organic matter and nutrient removal efficiencies in synthetic domestic wastewater, and on bacterial community structure and diversity in vermifiltration.

In this paper, we studied the effect of earthworm loads on the removal rates of chemical oxygen demand (COD), ammonia nitrogen (NH3-N), total nitrogen, and total phosphorus from synthetic domestic sewage and on the bacterial community structure and diversity of substrates in earthworm packing beds. The different vermifiltrations (VFs), including the control, are successful in removing both organic matter (OM) and nutrients. The removal rate of NH3-N at 12.5 g of earthworm/L of soil VF is higher compared with that at 0 and 4.5 earthworm load VFs. The highest Shannon index, in the earthworm packing bed, occurred at 16.5 earthworm load VF. Furthermore, the COD removal rate is significantly correlated with the Shannon index, which reveals that OM removal for synthetic domestic sewage treatment at VF might be more dependent on bacterial diversity at the earthworm packing bed. The band distributions and diversities of the bacterial community for samples from different earthworm loads in VFs suggest that the bacterial community structure was only affected within the earthworm packing bed when the earthworm load reached a certain level. The present study adds to the current understanding of OM and nutrient degradation processes in VF domestic wastewater treatment.

[Hemorrhage-prevention value of second-look endoscopy after endoscopic submucosal dissection for early gastric cancer: a meta-analysis].

Objective: To use the meta-analysis in evaluating the hemorrhage-prevention value of second-look endoscopy after endoscopic submucosal dissection (ESD) for early gastric cancer. Methods: A literature search was conducted to identify all relevant studies comparing second-look endoscopy and non-second-look endoscopy after gastric ESD. The Medline/PubMed, Ovid, Elsevier ScienceDirect, EBSCO, CNKI and VIP databases were searched systematically. Literature inclusion criteria: (1) all the patients were diagnosed as early gastric cancer receiving ESD; (2) end point of the study included postoperative bleeding rate of ESD. Exclusion criteria: (1) papers of repeated research, review, comment, guideline, etc; (2) non-control study. Meta-analysis method was used to calculate a pooled odds ratio (OR) for developing post-ESD bleeding. Results: The meta-analysis showed that post-ESD bleeding was observed in 40 of 1287 patients (3.1%) without second-look endoscopy and in 40 of 968 patients (4.1%) with second- look endoscopy (OR=1.25, 95% CI: 0.79-1.98), with no significant difference between these two groups. Subgroup analysis on research method still indicated no significant difference of post-ESD bleeding between RCT group (OR=1.45,95%CI: 0.79-2.65) and non-RCT group (OR=1.02, 95%CI: 0.50-2.08) (all P>0.05). Conclusion: Based on meta analysis, second-look endoscopy can not reduce the rate of postoperative bleeding of ESD. Therefore, routine second-look endoscopy after gastric ESD may not be necessary to prevent delayed postoperative bleeding of ESD.