Humin as an Electron Mediator for Microbial Reductive Dehalogenation

We report that humins extracted as the solid fractions from paddy soils or sediment are involved in extracellular electron transfer, coupled with microbial reductive dehalogenation of pentachlorophenol (PCP), by serving as both electron acceptor and electron donor. In our system, humin is requisite for the dechlorination of PCP, and this activity cannot be maintained when humin is replaced with soluble humic substances or related compounds, including 0.1 M NaOH-extracted humic acid from soil, Aldrich humic acid, and anthraquinone-2,6-disulfonate. The function of humins is stable against treatments with H₂O₂ (30%, 30 min), HCl (0.1 M, 48 h), NH₂OH·HCl (0.1 M, 48 h), NaBH₄ (0.1 M, 15 h), and heat (121 °C, 30 min). Cyclic voltammograms indicated that humin harbors redox-active moieties, and electron spin resonance suggested that quinone moieties within humin are the redox-active centers. Fourier-transform infrared and nuclear magnetic resonance analyses verified the presence of the aryl carbonyl carbon group in humin. Although the proportion of redox-active carbon is very small, the potential electron-mediating ability is not negligible. The finding that humin, in solid form, is redox active has important implications for in situ bioremediation, given the wide distribution of humin and the diversity and ubiquity of humic substance-utilizing microorganisms

Determining optimal maintenance schedules for adjuvant intravesical bacillus Calmette–Guerin immunotherapy in non-muscle-invasive bladder cancer: a systematic review and network meta-analysis

<p><b>Objectives:</b> To figure out optimal bacillus Calmette–Guerin (BCG) maintenance schedules for non-muscle-invasive bladder cancer (NMIBC) patients by comparing different schedules in a systematic review using conventional and network meta-analysis.</p> <p><b>Materials and methods:</b> Literature was searched in the databases of Medline, Embase, Cochrane library, Clinicaltrials.gov, Wanfang, CNKI and SinoMed in April 2016 and 9 randomized clinical trials comparing intravesical BCG maintenance therapy with BCG induction-only therapy or comparing different BCG maintenance schedules (induction-only, 1 year, 1.5 year, 2 year, 3 year maintenance) in NMIBC patients were included. Conventional and network meta-analyses within a Bayesian framework were performed to calculate odds ratios of tumor recurrence, progression and side effects (cystitis, hematuria, general malaise and fever). The surface under the cumulative ranking curve (SUCRA) mean ranking was used to obtain schedule hierarchy.</p> <p><b>Results:</b> Data from 1951 patients showed that longer-term maintenance BCG therapy does not significantly decrease tumor recurrence and progression rate of NMIBC compared to shorter-term maintenance BCG therapy. However, longer-maintenance therapy does not increase side effect incidence compared to induction-only therapy. According to SUCRA results, induction-only therapy has the highest probability of recurrence and progression but least probability of side effects.</p> <p><b>Conclusions:</b> Longer BCG maintenance therapy (such as 3 years) is not superior to shorter maintenance therapy (such as 1 year). But maintenance therapy overall is better than induction-only BCG therapy while not increasing side effects. Though further evidence and clinical practice with balanced confounding factors (risk stratification and BCG strain) are wished for, the current study suggests the common use of 1 year intravesical BCG instillation for NMIBC patients.</p

Graphene Oxide Quantum Dots Incorporated into a Thin Film Nanocomposite Membrane with High Flux and Antifouling Properties for Low-Pressure Nanofiltration

Graphene oxide quantum dots (GOQDs), novel carbon-based nanomaterials, have attracted tremendous research interest due to their unique properties associated with both graphene and quantum dots. In the present study, thin film nanocomposite (TFN) membranes comprising GOQDs dispersed within a tannic acid (TA) film were fabricated by an interfacial polymerization reaction for low-pressure nanofiltration (NF). The resultant TA/GOQDs TFN membranes had measurably smoother and more hydrophilic, negatively charged surfaces compared to the similarly formed TA thin film composite (TFC) membrane. Owing to the loose active layer structure and the combination of Donnan exclusion and steric hindrance, the TA/GOQDs TFN membrane showed a pure water flux up to 23.33 L/m²·h (0.2 MPa), which was 1.5 times more than that of pristine TA TFC membrane, while high dye rejection to Congo red (99.8%) and methylene blue (97.6%) was kept. In addition, the TA/GOQDs TFN membrane presented better antifouling properties, which was ascribed to the favorable changes in membrane hydrophilicity, ζ-potential, and surface roughness. These results indicated the great potential of such membranes in wastewater treatment, separation, and purification in many industrial fields

High-Performance PEBA2533-Functional MMT Mixed Matrix Membrane Containing High-Speed Facilitated Transport Channels for CO₂/N₂ Separation

A novel mixed matrix membrane was fabricated by establishing montmorillonite (MMT) functionalized with poly­(ethylene glycol) methyl ether (PEG) and aminosilane coupling agents in a PEBA membrane. The functional MMT played multiple roles in enhancing membrane performance. First, the MMT channels could be used as high-speed facilitated transport channels, in which the movable metal cations acted as carriers of CO₂ to increase the CO₂ permeability. Second, due to mobility of long-chain aminos and reversible reactions between CO₂ and amine groups, the functional MMT could actively catch the CO₂, not passively wait for arrival of CO₂, which can facilitate the CO₂ transport. At last, PEG consisting of EO groups had excellent affinity for CO₂ to enhance the CO₂/N₂ selectivity. Thus, the as-prepared functional MMMs exhibited good CO₂ permeability and CO₂/N₂ selectivity. The functional MMM doped with 40 wt % of MMT-HD702-PEG5000 displayed optimal gas separation with a CO₂ permeability of 448.45 Barrer and a CO₂/N₂ selectivity of 70.73, surpassing the upper bound lines of the Robeson study of 2008

Insoluble Fe-Humic Acid Complex as a Solid-Phase Electron Mediator for Microbial Reductive Dechlorination

We report that the insoluble Fe-HA complex, which was synthesized with both commercial Aldrich humic acid (HA) and natural HA, functions as a solid-phase electron mediator (EM) for the anaerobic microbial dechlorination of pentachlorophenol. Spectroscopic characterizations and sequential Fe extraction demonstrated that the Fe-HA complex was predominated with Na₄P₂O₇-labile Fe (represented as the organically bound Fe fraction) and poorly ordered Fe fraction (the fraction left in the residue after the sequential extraction), which were associated with different possible binding processes with carboxylate and phenolic groups. The change in the electron-mediating activity caused by Fe extraction indicated that the electron-mediating function of the Fe-HA complex is attributable to the Na₄P₂O₇-labile Fe fraction. The Fe-HA complex also accelerated the microbial reduction of Fe­(III) oxide, which suggested the presence of multiple electron-mediating functions in the complex. The electron shuttle assay showed that the Fe-HA complex had an electron-accepting capacity of 0.82 mequiv g^–1 dry Fe-HA complex. The presence of redox-active moieties in the Fe-HA complex was verified by cyclic voltammetry analysis of the sample after electrical reduction, with a redox potential estimated at 0.02 V (vs a standard hydrogen electrode)

Human Gut Microbiota Changes Reveal the Progression of Glucose Intolerance

<div><p>To explore the relationship of gut microbiota with the development of type 2 diabetes (T2DM), we analyzed 121 subjects who were divided into 3 groups based on their glucose intolerance status: normal glucose tolerance (NGT; n = 44), prediabetes (Pre-DM; n = 64), or newly diagnosed T2DM (n = 13). Gut microbiota characterizations were determined with 16S rDNA-based high-throughput sequencing. T2DM-related dysbiosis was observed, including the separation of microbial communities and a change of alpha diversity between the different glucose intolerance statuses. To assess the correlation between metabolic parameters and microbiota diversity, clinical characteristics were also measured and a significant association between metabolic parameters (FPG, CRP) and gut microbiota was found. In addition, a total of 28 operational taxonomic units (OTUs) were found to be related to T2DM status by the Kruskal-Wallis H test, most of which were enriched in the T2DM group. Butyrate-producing bacteria (e.g. <i>Akkermansia muciniphila</i> ATCCBAA-835, and <i>Faecalibacterium prausnitzii</i> L2-6) had a higher abundance in the NGT group than in the pre-DM group. At genus level, the abundance of <i>Bacteroides</i> in the T2DM group was only half that of the NGT and Pre-DM groups. Previously reported T2DM-related markers were also compared with the data in this study, and some inconsistencies were noted. We found that <i>Verrucomicrobiae</i> may be a potential marker of T2DM as it had a significantly lower abundance in both the pre-DM and T2DM groups. In conclusion, this research provides further evidence of the structural modulation of gut microbiota in the pathogenesis of diabetes.</p></div

The Therapeutic Response of Gastrointestinal Stromal Tumors to Imatinib Treatment Assessed by Intravoxel Incoherent Motion Diffusion-Weighted Magnetic Resonance Imaging with Histopathological Correlation

<div><p>Purpose</p><p>To exploit the intravoxel incoherent motion (IVIM) diffusion-weighted (DW) MRI when evaluating the therapeutic response of gastrointestinal stromal tumors (GIST) to Imatinib in a mouse model.</p><p>Materials and Methods</p><p>Mice with xenografts bearing cells from the GIST-T1 cell line were randomly divided into a treated group receiving Imatinib and a control group. DWMRI scans with 14 b-values (0–1500 s/mm²) were performed before and after treatment (days 1, 3 and 7). IVIM related parameters perfusion fractions (<i>f</i>p) and perfusion-related diffusion coefficients (D*) and the conventional apparent diffusion coefficients (ADC) were calculated by fitting the DWMRI signal decay. The mean changes from baseline to each post-treatment time point for each measurement (ΔADC, Δ<i>f</i>p and ΔD*) were calculated. The differences of mean changes between the two groups were tested for statistical significance. Histopathological analyses including Ki-67, CD31, TUNEL and H&E were conducted in conjunction with the MRI scans.</p><p>Results</p><p>Increases in ADC of the treated group were higher than those of the control group after treatment, whereas statistical significances were not observed. Compared to the control group, D* in the treated group decreased significantly (ΔD*_treated = -41%, -49%, and -49% with <i>P</i> = 0.0001, 0.0001 and 0.0001), and <i>f</i>p increased significantly (Δ<i>f</i>p_treated = 79%, 82% and 110%, with <i>P</i> = 0.001, 0.0001 and <i>P</i> = 0.0007) on days 1, 3 and 7 after treatment. Histopathological analyses demonstrated different tumor tissue characteristics between the treated and control groups.</p><p>Conclusion</p><p>IVIM measurements may serve as more sensitive imaging biomarkers than ADC when assessing GIST response to Imatinib as early as one day after treatment.</p></div

Kruskal-Wallis H tests of associations between glucose intolerance status and microbiota composition (OTUs level).

a<p>The relative abundance of OTUs enriched in the NGT group decreased to 0 with the development of T2DM.</p>b<p>The relative abundance of OTUs increased with the development of T2DM.</p><p>NGT = normal glucose tolerance; OTU = operational taxonomic unit; Pre-DM = prediabetes; T2DM = type 2 diabetes mellitus.</p

Co-inertia analysis (CIA) of the relationship between microbiota at the OTU level, clinical parameters, and disease group.

<p>The upper left panel shows the CIA of the clinical parameter principal component analysis (PCA) and the microbiota PCA; arrows indicate where samples in the clinical parameter dataset are relative to the microbiota dataset. Red lines represent the NGT group, green lines the Pre-DM group, and blue lines the T2DM group. The upper right panel shows clinical parameter loading data; the lower panel displays the associated microbiota at the OTU level (labeled with their annotations). Only OTUs present in at least 1% of the samples were used in the analysis. CIA was performed with R package ‘ade4’. OTU = operational taxonomic unit.</p

Alpha diversity of the 3 groups.

<p>The Shannon index (left panel) and Chao1 index (right panel) were computed for all 121 subjects. The box depicts the interquartile range (IQR) between the first and third quartiles (25th and 75th percentiles, respectively) and the line inside the box denotes the median.</p