Influence of secondary water supply systems on microbial community structure and opportunistic pathogen gene markers

Secondary water supply systems (SWSSs) refer to the in-building infrastructures (e.g., water storage tanks) used to supply water pressure beyond the main distribution systems. The purpose of this study was to investigate the influence of SWSSs on microbial community structure and the occurrence of opportunistic pathogens, the latter of which are an emerging public health concern. Higher numbers of bacterial 16S rRNA genes, Legionella and mycobacterial gene markers were found in public building taps served by SWSSs relative to the mains, regardless of the flushing practice (P < 0.05). In residential buildings, genes of L. pneumomhila, Acanthamoeba and Vermamoeba vermiformis were primarily detected in tanks and taps compared to the mains. Long water retention time, warm temperature and loss of disinfectant residuals promoted microbial growth and colonization of potential pathogens in SWSSs. Varied levels of microbial community shifts were found in different types of SWSSs during water transportation from the distribution main to taps, highlighting the critical role of SWSSs in shaping the drinking water microbiota. Overall, the results provided insight to factors that might aid in controlling pathogen proliferation in real-world water systems using SWSSs.

Risk factors associated with multidrug-resistant tuberculosis (MDR-TB) in a tertiary armed force referral and teaching hospital, Ethiopia

Background

Ethiopia is one of the world health organization defined higher tuberculosis (TB) burden countries where the disease remains a massive public health threat. This study aimed to identify the prevalence and associated factors of multidrug-resistant tuberculosis (MDR-TB) using all armed force and civilian TB attendants in a tertiary level armed force hospital, where data for MDR-TB are previously unpublished.

Methods

Cross-sectional study was conducted from September 2014 to August 2015 in a tertiary level Armed Force Referral and Teaching Hospital (AFRTH), Ethiopia. Armed force members (n = 251) and civilians (n = 130) which has been undergone TB diagnosis at AFRTH were included. All the specimens collected were subjected to microscopic smear observation, culture growth and drug susceptibility testing. Data were analyzed using statistical package for social sciences following binary logistic regression and Chi-square. P-values < 0.05 were considered statistically significant.

Results

Among 381 TB patients, 355 (93.2%) new and 26 (6.8%) retreatment cases were identified. Culture and smear positive TB cases were identified in 297 (77.9%) and 252 (66.1%) patients, respectively. The overall prevalence of MDR-TB in AFRTH was found 1.8% (1.3% for armed force members and 0.5% for civilian patients) all of which were previously TB treated cases. The entire treatment success rates were 92.6% achieved highest in the armed force (active and pension) than the civilian patients. The failure and dead cases were also found 2.5 and 4.6%, respectively. Using bivariate analysis, category of attendants and TB contact history were strong predictors of MDR-TB in armed force and civilian patients. Moreover, human immunodeficiency virus (HIV) infection also identified a significant (OR = 14.6; 95% CI = 2.3–92.1; p = 0.004) predicting factor for MDR-TB in armed force members. However, sex, age and body mass index were not associated factor for MDR-TB.

Conclusions

In AFRTH, lower prevalence of MDR-TB was identified in armed force and civilian patients that were significantly associated with category of attendants, HIV infection and TB contact history. Considering armed force society as one segment of population significantly helps to plan a better MDR-TB control management, especially for countries classified as TB high burden country.

Multicolor GLUT5-permeable fluorescent probes for fructose transport analysis

The specificity of carbohydrate transporters towards their substrates poses a significant challenge for the development of molecular probes to monitor sugar uptake in cells for biochemical and biomedical applications. Herein we report a new set of coumarin-based fluorescent sugar conjugates applicable for the analysis of fructose uptake due to their free passage through the fructose-specific transporter GLUT5. The reported probes cover a broad range of the fluorescence spectrum providing essential tools for the evaluation of fructose transport capacity in live cells.

Secukinumab demonstrates high sustained efficacy and a favourable safety profile in patients with moderate-to-severe psoriasis through 5 years of treatment (SCULPTURE Extension Study)

BACKGROUND

Secukinumab, a fully human monoclonal antibody that selectively neutralizes IL-17A, has been shown to have significant efficacy and a favourable safety profile in the treatment of moderate-to-severe psoriasis and psoriatic arthritis.

OBJECTIVE

To assess the efficacy and safety of secukinumab through 5 years of treatment in moderate-to-severe psoriasis.

METHODS

In the core SCULPTURE study, Psoriasis Area and Severity Index (PASI) 75 responders at Week 12 continued receiving subcutaneous secukinumab until Year 1. Thereafter, patients entered the extension phase and continued treatment as per the core trial. Treatment was double-blinded until the end of Year 3 and open-label from Year 4. Here, we focus on the 300 mg fixed-interval (every 4 weeks) treatment, the recommended per label dose. Efficacy data are primarily reported as observed, but multiple imputation (MI) and last observation carried forward (LOCF) techniques were also undertaken as supportive analyses.

RESULTS

At Year 1, 168 patients entered the extension study and at the end of Year 5, 126 patients completed 300 mg (every 4 weeks) treatment. PASI 75/90/100 responses at Year 1 (88.9%, 68.5% and 43.8%, respectively) were sustained to Year 5 (88.5%, 66.4% and 41%). PASI responses were consistent regardless of the analysis undertaken (as observed, MI, or LOCF). The average improvement in mean PASI was approximately 90% through 5 years compared with core study baseline. DLQI (dermatology life quality index) 0/1 response also sustained through 5 years (72.7% at Year 1 and 65.5% at Year 5). The safety profile of secukinumab remained favourable, with no cumulative or unexpected safety concerns identified.

CONCLUSION

Secukinumab 300 mg treatment delivered high and sustained levels of skin clearance and improved quality of life through 5 years in patients with moderate-to-severe psoriasis. Favourable safety established in the secukinumab phase 2/3 programme was maintained through 5 years.

Comparison of palygorskite and struvite supported palygorskite derived from phosphate recovery in wastewater for in-situ immobilization of Cu, Pb and Cd in contaminated soil

A phosphorus-bearing product S-PAL obtained from nutrient-rich wastewater was reused as ameliorant for Cu, Pb and Cd immobilization in contaminated soil with three different rates (1%, 5% and 10% w/w). The 0.01 mol/L CaCl₂ -extractability of metals significantly reduced with increasing rate of PAL and S-PAL in the first 7-day immobilization and insignificantly changed after 14-day immobilization. Compared with PAL, the lower metal extractability was observed after S-PAL addition. The BCR sequential extraction results showed that both of amendments were beneficial to transform acid soluble fraction to residual fraction. The XRD patterns of soil samples after immobilization evidenced that the formation of metal-bearing phosphate precipitates and the combination between functional groups such as Si-OH and metals played a key role for metal immobilization by S-PAL and PAL. Dominant phyla across all samples were Fusobacteria, Proteobacteria and Actinobacteria, and the relative abundance of Fusobacteria decreased under S-PAL treatment. The pH-dependent leaching test indicated that the metal release at a defined pH was not affected by the presence of PAL. Compared with S-PAL, the metals amended by PAL in soil were easier to release at acidic pH since the combination between functional groups and metals instead the formation of new metal-bearing precipitate.

Influencing characteristics of short-time aerobic digestion on spatial distribution and adsorption capacity of extracellular polymeric substances in waste activated sludge

The spatial distribution and adsorption capacity of extracellular polymeric substances (EPS) were systematically investigated for waste activated sludge (WAS) treated by a short-time aerobic digestion (STAD) process.

New insights into the plasmonic enhancement for photocatalytic H2 production by Cu–TiO2 upon visible light illumination

Cu nanoparticles were deposited on the surface of commercial TiO₂ nanoparticles (Cu–TiO₂) using different methods aiming at the production of highly efficient visible light photocatalysts.

Assessing membrane biofouling and its gel layer of anoxic/oxic membrane bioreactor for megacity municipal wastewater treatment during plum rain season in Yangtze River Delta, China

This study assessed membrane biofouling and its gel layer of anoxic/oxic membrane bioreactor (A/O-MBR) for megacity municipal wastewater treatment during plum rain season, which was continuous rainy weather, in Yangtze River Delta, China. A laboratory-scale A/O-MBR was operated to treat the municipal wastewater from Quyang wastewater treatment plant, which located at the typical megacity of Shanghai in Yangtze River Delta, from April to July accompanying with plum rain season. As reactor performance showed, COD_Cr, NH₄⁺-N, TN, TP of the influent gradually decreased during plum rain season, and inhibited pollutant removal due to organic carbon shortage. However, dissolve inorganic carbon and inorganic components in mixed liquid had an obvious increase under rainy weather. Membrane filtration results indicated that plum rain season enhanced pore blocking behavior, further leading to the serious membrane biofouling but inhibiting gel layer formation. Additionally, gel layer analysis predicted that plum rain season led to plenty of inorganic components and precipitate flew into A/O-MBR reactor. Inorganic components with elements of Ca, Mg Ba, Fe, Al and Si seriously blocked membrane pores. Those components also accumulated into gel layer in the form of SiO₂, CaCO₃, CaSiO₃, MgNH₄PO₄, BaCO₃, AlPO_4, etc. Consequently, plum rain season enhanced pore blocking behavior and led to severe membrane biofouling but with the inhibition of gel layer formation.

How myristyltrimethylammonium bromide enhances biomass harvesting and pigments extraction from Synechocystis sp. PCC 6803

Myristyltrimethylammonium bromide (MTAB) is a cationic surfactant used to improve biomass harvesting and pigment extraction form microalgae, but the mechanisms underlying its effectiveness are poorly defined. We document the mechanisms for enhanced harvesting and pigment extraction for the cyanobacterium Synechocystis sp. PCC 6803 using measurements from flow cytometer, zeta potential, release of soluble components, and microscopy. Harvesting efficiency increased as the MTAB/Biomass dose increased from 0 to 40%. A low MTAB dose (≤ 8%) mainly brought about coagulation and flocculation, which led to aggregation that improved harvesting, but 40% MTAB had the highest harvesting efficiency, 62%. Adding MTAB above a MTAB/Biomass dose of 8% also increased cell-membrane permeability, which allowed the solvent (ethyl acetate) to pass into the cells and resulted in a large increase in extraction efficiency of pigments: An MTAB/Biomass ratio of 60% for 180 min achieved the highest extraction efficiencies of chlorophyll and carotenoids, 95% and 91%, respectively. Combining harvesting and extraction performances with results from flow cytometry, zeta potential, release of soluble components, and microscopy lead to the following mechanistic understandings. MTAB dose from 8% to 40% solubilized EPS, which lowered the biomass's negative charge, but caused breakup of the large aggregates. An increase of cell permeability also in this stage allowed ethyl acetate to pass into the cells and achieve better pigment extraction. MTAB >40% led to cell lysis and a large increase in soluble organics, but complete cell lysis was not required to achieve the maximum extraction efficiency. The MTAB/Biomass % ratio for optimizing harvest efficiency and pigment extraction lay in the range of 40%-60%.

New insights into comparison between synthetic and practical municipal wastewater in cake layer characteristic analysis of membrane bioreactor

In previous studies, cake layer analysis in membrane bioreactor (MBR) was both carried out with synthetic and practical municipal wastewater (SMW and PMW), leading to different results. This study aimed to identify the comparison between SMW and PMW in cake layer characteristic analysis of MBR. Two laboratory-scale anoxic/oxic MBRs were operated for over 90days with SMW and PMW, respectively. Results showed that PMW led to rough cake layer surface with particles, and the aggravation of cake layer formation with thinner and denser cake layer. Additionally, inorganic components, especially Si and Al, in PMW accumulated into cake layer and strengthened the cake layer structure, inducing severer biofouling. However, SMW promoted bacterial metabolism during cake layer formation, thus aggravated the accumulation of organic components into cake layer. Therefore, SMW highlighted the organic components in cake layer, but weakened the inorganic functions in practical MBR operation.

Enhancement mechanisms of short-time aerobic digestion for waste activated sludge in the presence of cocoamidopropyl betaine

Cocoamidopropyl betaine (CAPB), which is a biodegradable ampholytic surfactant, has recently been found to dramatically enhance the aerobic digestion of waste activated sludge (WAS) in short-time aerobic digestion (STAD) systems. Therefore, it is important to understand the mechanisms in which CAPB enhances WAS aerobic digestion performance. Results showed that CAPB could dramatically enhance the solubilization of soluble proteins (PN), polysaccharides (PS), nucleic acids (NA) and humic-like substances (HS) in the STAD system within the initial 2 h. Then PN, PS and NA gradually decreased, while HS showed only minor decease. In addition, CAPB increased the proportion of low MW fractions (<20 kDa) from 4.22% to 39.4%, which are more biodegradable. Specific oxygen uptake rates and dehydrogenase enzyme activity results indicated that CAPB markedly improved the aerobic microorganism activities. Microbial community analyses and principle coordinate analyses (PCoA) revealed that CAPB increased the proportion of some functional microorganisms, including Proteobacteria, Planctomycetales, Acinetobacter, Pseudomonas and Aeromonas. The changes driven by CAPB could explain the enhanced performance of the STAD system for WAS aerobic treatment.

DHX15 promotes prostate cancer progression by stimulating Siah2-mediated ubiquitination of androgen receptor

Androgen receptor (AR) activation is critical for prostate cancer development and progression, including castration-resistance. The nuclear export signal of AR (NES^AR) plays an important role in AR intracellular trafficking and proteasome-dependent degradation. Here, we identified the RNA helicase DHX15 as a novel AR co-activator using a yeast mutagenesis screen and revealed that DHX15 regulates AR activity by modulating E3 ligase Siah2-mediated AR ubiquitination independent of its ATPase activity. DHX15 and Siah2 form a complex with AR, through NES^AR. DHX15 stabilized Siah2 and enhanced its E3 ubiquitin ligase activity, resulting in AR activation. Importantly, DHX15 was upregulated in prostate cancer specimens and its expression was correlated with Gleason scores and PSA recurrence. Furthermore, DHX15 immunostaining correlated with Siah2. Finally, DHX15 knockdown inhibited the growth of C4-2 prostate tumor xenografts in mice. Collectively, our data argue that DHX15 enhances AR transcriptional activity and contributes to prostate cancer progression through Siah2.

The distribution of phosphorus and its transformations during batch growth of Synechocystis

Phosphorus (P) is an essential nutrient that affects the growth and metabolism of microalgal biomass. Despite the obvious importance of P, the dynamics of how it is taken up and distributed in microalgae are largely undefined. In this study, we tracked the fate of P during batch growth of the cyanobacterium Synechocystis sp. PCC 6803. We determined the distribution of P in intracellular polymeric substances (IPS), extracellular polymeric substances (EPS), and soluble microbial products (SMP) for three initial ortho-phosphate concentrations. Results show that the initial P concentration had no impact on the production of biomass, SMP, and EPS. While the initial P concentration affected the rate and the timing of how P was transformed among internal and external forms of inorganic P (IP) and organic P (OP), the trends were the same no matter the starting P concentration. Initially, IP in the bulk solution was rapidly and simultaneously adsorbed by EPS (IP_EPS) and taken up as internal IP (IP_int). As the bulk-solution's IP was depleted, desorption of IP_EPS became the predominant source for IP that was taken up by the growing cells and converted into OP_int. At the end of the 9-d batch experiments, almost all P was OP, and most of the OP was intracellular. Based on all of the results, we propose a set of transformation pathways for P during the growth of Synechocystis. Key is that EPS and intracellular P pool play important and distinct roles in the uptake and storage of P.

[Liposuction combined with lymphatico-venous anastomosis for treatment of secondary lymphedema of the lower limbs: a report of 49 cases]

Objective: To study the clinical effects of liposuction combined with lymphatico-venous anastomosis for treatment of secondary lymphedema of the lower limbs. Methods: A retrospective analysis was performed for 49 patients who had undergone liposuction combined with lymphatico-venous anastomosis to treat secondary lymphedema of the lower limbs at Department of Lymph Surgery, Beijing Shijitan Hospital from November 2013 to February 2015.All patients were female aging from 31 to 70 years with median age of (52±10)years.All patients had history of pelvic surgery.There were 32 cases with cervical carcinoma, 11 cases with endometrial cancer, 1 case with ovarian cancer who accepted radical hysterectomy, 2 cases with benign tumor who accepted resection, 2 cases accepted inguinal lymph node dissection, 1 case with rectal cancer accepted radical resection.There were 30 cases with history of radiation therapy and 23 cases with history of erysipelas recurrent((2.1±3.9)/year). The limb swelling degree in preoperative and postoperative patients was explored using one-way analysis of variance with replicate measures and paired sample t-test. Meanwhile the incidence of lymphogenous infection was used as an evaluation of operation efficacy. Results: The mean lower limb circumference difference at 7 days, 6 months and 12 months was (0.17±1.36)cm, (1.25±1.62)cm and(1.58±1.56)cm, respectively, which was significantly decreased compared with preoperative((4.92±2.16)cm) (t=-5.712, -5.777, -5.765; all P<0.01). The mean lower limb volume difference at 7 days, 6 months and 12 months was (522±799)ml, (726±973)ml and (889±895)ml, respectively, which was significantly decreased compared with preoperative((2 729±1 335) ml)(t=-5.905, -6.093, -5.777; all P<0.01). The incidence of erysipelas was 0.0(0.0, 0.0)/6 months within 6 months after operation and 0.0(0.0, 0.0)/6 months within 6-12 months after operation, which was significantly lower than that before operation(0.0(0.0, 2.0)/year). The feeling of tightness and heaviness of the limb was significantly improved compared with preoperative. Conclusion: Liposuction combined with lymphatico-venous anastomosis is an effective method for the treatment of secondary lymphedema of the lower limbs.

New and practical mathematical model of membrane fouling in an aerobic submerged membrane bioreactor

This study aimed to develop a practical semi-empirical mathematical model of membrane fouling that accounts for cake formation on the membrane and its pore blocking as the major processes of membrane fouling. In the developed model, the concentration of mixed liquor suspended solid is used as a lumped parameter to describe the formation of cake layer including the biofilm. The new model considers the combined effect of aeration and backwash on the foulants' detachment from the membrane. New exponential coefficients are also included in the model to describe the exponential increase of transmembrane pressure that typically occurs after the initial stage of an MBR operation. The model was validated using experimental data obtained from a lab-scale aerobic sponge-submerged membrane bioreactor (MBR), and the simulation of the model agreed well with the experimental findings.

Biodecolorization of textile azo dye using Bacillus sp. strain CH12 isolated from alkaline lake

Textile azo dye decolorizing bacteria were isolated from alkaline Lakes Abaya and Chamo using Reactive Red 239 (RR239) dye. Through subsequent screening process, strain CH12 was selected to investigate the effects of nutrient supplement, DO, pH, temperature, dye concentration and types on decolorization. Based on 16S rRNA gene sequence analysis, strain CH12 was identified as Bacillus sp. Decolorization efficiencies were significantly enhanced with carbon (≥98%) and organic nitrogen (∼100%) supplements. Complete decolorization was also observed under anoxic and anaerobic conditions, and at the temperature of 30 °C and the pH of 10. However, the azo dye decolorization efficiency of strain CH12 was significantly reduced when NaNO₃ (1-8%) was supplemented or under aerobic culturing condition (≤6%), indicating that RR239 was less preferred electron acceptor. Overall, strain CH12 can be a promising candidate for decolorization applications due to its potential to effectively decolorize higher RR239 concentrations (50-250 mg/L) and six additional dyes.

Butyrate and retinoic acid imprint mucosal-like dendritic cell development synergistically from bone marrow cells

Accumulating data show that the phenotypes and functions of distinctive mucosal dendritic cells (DCs) in the gut are regulated by retinoic acid (RA). Unfortunately, the exact role of butyrate in RA-mediated mucosal DC differentiation has not been elucidated thoroughly to date. Mucosal-like dendritic cell differentiation was completed in vitro by culturing bone marrow cells with growth factors [granulocyte-macrophage colony-stimulating factor (GM-CSF/interleukin (IL)-4], RA and/or butyrate. The phenotypes, cytokine secretion, immune functions and levels of retinal dehydrogenase of different DCs were detected using quantitative polymerase chain reaction (qPCR), enzyme-linked immunosorbent assay (ELISA) and flow cytometry, respectively. The results showed that RA-induced DCs (RA-DCs) showed mucosal DC properties, including expression of CD103 and gut homing receptor α₄ β₇ , low proinflammatory cytokine secretion and low priming capability to antigen-specific CD4⁺ T cells. Butyrate-treated RA-DCs (Bu-RA-DCs) decreased CD11c, but increased CD103 and α₄ β₇ expression. Moreover, the CD4⁺ T priming capability and the levels of retinal dehydrogenase of RA-DCs were suppressed significantly by butyrate. Thus, butyrate and retinoic acid have different but synergistic regulatory functions on mucosal DC differentiation, indicating that immune homeostasis in the gut depends largely upon RA and butyrate to imprint different mucosal DC subsets, both individually and collectively.

[The value of DCE-MRI in assessing the course of thyroid associated ophthalmopathy]

Objective: To explore the feasibility of the semi-quantitative rectus extraocular muscle (EOM) parameters of dynamic contrast-enhanced magetic resonance imaging (DCE-MRI) in assessing the clinical course of thyroid associated ophthalmopathy (TAO). Methods: It was a retrospective case series study. A total of 136 cases of TAO were recruited from March 2011 to October 2012 in the Tianjin the first center hospital including 63 males and 72 females, aged 24.0-65.0 years, with an average age of (40.5±10.9) years. Forty healthy volunteers were recruited as control group (CG). According to clinical activity score (CAS), all TAO patients were divided into 2 groups, activity group (AG) and inactivity group (IAG). MRI and DCE-MRI orbit scan were performed in each subject. Drew time-intensity curves (TIC) by Siemens 3.0 MR (syngo) post-processing workstation. The semi-quantitative parameters of DCE-MRI were calculated. The semi-quantitative paramters based on TIC include early enhancement coefficient (EEC), maximum enhancement coefficient (Emax) and wash-out coefficient (WC(5min)). Kruskal-Wallis H rank test was used for comparing signal intensity among 3 groups, and Nemenyi test for pairwise comparison between groups. The DCE-MRI parameters (EEC, Emax, WC(5 min)) among groups were compared by one-way ANOVA, and Bonferroni t test is for pairwise comparison between groups. The diagnostic value of mean EEC, mean Emax, WC(5min) for assessment of the clinical course in TAO was analyzed by ROC curve. Results: There were significant difference in signal intensity (SI) of rectus EOM on T(2)WI among CG, AG and IAG, which is significantly different in 88 cases of AG including 45 cases of high intensity 51.1%, 23 cases of moderate intensity 26.1%, and 20 cases of low intensity 22.7%,compared with CG and IAG. EEC (P<0.05), Emax and WC5min values of rectus EOM of TAO group were significantly lower than those of CG(P<0.05), which values of rectus EOM of TAO active group of EEC are 0.63±0.06、0.61±0.05、0.56±0.09、0.57±0.09, and values of rectus EOM of TAO inactive group of EEC are 0.49±0.05、0.50±0.08、0.57±0.10、0.55±0.09. The values of rectus EOM of TAO active group of Emax are 1.35±0.09、1.28±0.09、1.21±0.17、1.25±0.10, and the values of rectus EOM of TAO inactive group of Emax are 1.04±0.06、1.05±0.10、1.20±0.19、1.16±0.11. The values of rectus EOM of TAO active group of WC(5 min) are 0.13±0.03、0.13±0.03、0.13±0.06、0.13±0.03 and the values of rectus EOM of TAO inactive group of WC5min are 0.08±0.02、0.79±0.03、0.11±0.06、0.09± 0.03. EEC (χ(2)=9.20, P<0.05), Emax and WC(5min) values of rectus EOM of TAO group were significantly lower than those of CG (P<0.05). EEC, Emax and WC(5min) values of medial rectus and inferior rectus EOM of IAG were significantly lower than those of AG(P<0.05). WC(5min) values of superior rectus EOM of IAG were significantly lower than those of AG (P<0.05). There were no differences in EEC and Emax values of lateral rectus and superior rectus EOM between IAG and AG (P>0.05). There were no differences in WC(5min) values of lateral rectus EOM between IAG and AG (P>0.05). The area under the curve (AUC) were 0.771, 0.879, 0.898 for mean EEC, mean Emax, and mean WC(5min), respectively. Conclusion: The semi-quantitative paramters of DCE-MRI can show the clinical activity of TAO patients and can be considered as the quantitative index of TAO activity staging. (Chin J Ophthalmol, 2017, 53: 430-435).

Potential effects of loading nano zero valent iron discharged on membrane fouling in an anoxic/oxic membrane bioreactor

A laboratory-scale submerged anoxic-oxic membrane bioreactor for municipal wastewater was operated to investigate the potential effects of loading suspended nano zero valent iron (nZVI, 25 and 50 mg/L) discharged on the membrane fouling. nZVI transformed rapidly into Feⁿ⁺, generated reactive oxygen species (ROS) and caused oxidative stress. This result rapidly led to the cell lysis and bacteria death, and further resulted in the decrease of biomass and extracellular polymeric substances (EPS). nZVI also thinned the membrane fouling layer. But nZVI had no obvious effects on activated sludge particle size, EPS molecule weight distribution and VOCs constitution of membrane foulant. Additionally, nZVI released Feⁿ⁺ and mitigated the inorganic (mainly Si element) fouling through Feⁿ⁺ flocculation. Consequently, membrane fouling mitigation with nZVI discharged was mainly due to oxidative stress to bacteria and Feⁿ⁺ flocculation of nZVI.

Simultaneous Bioreduction of Multiple Oxidized Contaminants Using a Membrane Biofilm Reactor

  This study tests a hydrogen-based membrane biofilm reactor (MBfR) to investigate simultaneous bioreduction of selected oxidized contaminants, including nitrate (<inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="00178-ilm01.gif"/>-N), sulfate (<inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="00178-ilm15.gif"/>), bromate (<inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="00178-ilm26.gif"/>), chromate (Cr(VI)) and para-chloronitrobenzene (p-CNB). The experiments demonstrate that MBfR can achieve high performance for contaminants bioreduction to harmless or immobile forms in 240 days, with a maximum reduction fluxes of 0.901 g <inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="00178-ilm37.gif"/>-N/m2·d, 1.573 g <inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="00178-ilm48.gif"/>/m2·d, 0.009 g <inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="00178-ilm59.gif"/>/m2·d, 0.022 g Cr(VI)/m2·d, and 0.043 g p-CNB/m2·d. Increasing H2 pressure and decreasing influent surface loading enhanced removal efficiency of the reactor. Flux analysis indicates that nitrate and sulfate reductions competed more strongly than <inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="00178-ilm70.gif"/>, Cr(VI) and p-CNB reduction. The average H2 utilization rate, H2 flux, and H2 utilization efficiency of the reactor were 0.026 to 0.052 mg H2/cm3·d, 0.024 to 0.046 mg H2/cm2·d, and 97.5% to 99.3% (nearly 100%). Results show the hydrogen-based MBfR may be suitable for removing multiple oxidized contaminants in drinking water or groundwater.

Fabrication of HA/PEI-functionalized carbon dots for tumor targeting, intracellular imaging and gene delivery

Carbon quantum dots (CDs) as emerging carbon nano-materials have attracted tremendous attention in biomedical fields due to unique properties.