Development of specific membrane bioreactors for membrane fouling control during wastewater treatment for reuse

University of Technology Sydney. Faculty of Engineering and Information Technology.In recent years, membrane fouling has become a critical issue of membrane bioreactor (MBR) in wastewater treatment. To resolve this obstacle, introducing biomass carriers or flocculants into submerged MBR (SMBR) has become one of the effective technologies for membrane fouling control. This study aims to provide an in-depth analysis on membrane fouling behaviour in SMBRs with sponge and/or the patented green bioflocculant by considering the properties of activated sludge and cake layer. A new functional media (sponge modified plastic carrier) was also developed to enhance the performance of integrated moving bed biofilm reactor-membrane bioreactor (MBBR-MBR) systems. The results suggested that sponge addition in a SMBR (SSMBR) or bioflocculant addition in a SMBR (MBR-G) reduced cake layer formation and limited pore blocking, thus effectively minimizing membrane fouling. Better sludge characteristics were obtained in both of the SSMBR and the MBR-G due to less soluble microbial products (SMP), lower biomass growth and sludge viscosity, higher protein to polysaccharide ratio in extracellular polymeric substances, higher zeta potential, greater relative hydrophobicity, larger floc size and better flocculation ability. The presence of sponge or bioflocculant in the SMBR also eliminated extracellular polymeric substances (EPS), SMP and/or biopolymer clusters (BPC) on membrane surface. Consequently, cake layer (Rc) and pore blocking resistance (Rp) were decreased in the SSMBR and the MBR-G. A modified resistance-in-series model proposed for the SMBR with and without bioflocculant could quantitatively demonstrate the impacts of sludge characteristics on membrane fouling. In the SSMBR, a longer hydraulic retention time (HRT) of 6.67 h permitted more considerably fouling reduction comparing to shorter HRTs (5.33 and 4.00 h). Moreover, lower Rp and Rc at the prolonged HRT were mainly ascribed to the elevated protein to polysaccharide ratio in SMP (SMPp/SMPc) of mixed liquor, together with the declined EPS and BPC in cake layer. SMP was not the primary membrane foulant when the SSMBRs were operated at different HRTs. Bioflocculant addition at the optimum HRT of 6.67 h further mitigated fouling in the SSMBR by improving activated sludge and cake layer characteristics. The integrated MBBR-MBR with the sponge modified plastic carriers showed better removal of DOC, NH₄₋N, T-N and PO₄₋P than the MBBR-MBR with plastic carriers only. Furthermore, the sponge modified plastic carriers also eliminated SMP of mixed liquor, and reduced SMP and BPC on membrane surface, which ameliorated membrane fouling, Rp and Rc as compared to the plastic carriers

A CASE STUDY IN PHARMACOLOGIC IMAGING USING PRINCIPAL CURVES IN SINGLE PHOTON EMISSION COMPUTED TOMOGRAPHY

In this manuscript we are concerned with functional imaging of the colon to assess the kinetics of a microbicide lubricant. The overarching goal is to understand the distribution of the lubricant in the colon. Such information is crucial for understanding the potential impact of the microbicide on HIV viral transmission. The experiment was conducted by imaging a radiolabeled lubricant distributed in the subject’s colon. The tracer imaging was conducted via single photon emission computed tomography (SPECT), a non-invasive, in-vivo functional imaging technique. We develop a novel principal curve algorithm to construct a three dimensional curve through the colon images. The developed algorithm is tested and debugged on several difficult two dimensional images of familiar curves where the original principal curve algorithm does not apply. The final curve fit to the colon data is compared with experimental sigmoidoscope collection

Optimization of Solanum lyratum Crude Polysaccharide Extraction Process Using Response Surface Methodology and Analysis ofIts In Vitro Antioxidant Activity

To optimize the extraction process of polysaccharide form Solanum lyratum and investigate its in vitro antioxidative activity. In this study, response surface methodology was employed to optimize the ultrasonic-assisted extraction process of polysaccharides from Solanum lyratum. Single-factor experiments were conducted to explore the effects of three factors: Extraction temperature, extraction time, and solid-liquid ratio on the yield. Fourier transform infrared spectroscopy (FTIR) was used to analyze the structure of Solanum lyratum polysaccharide, and in vitro antioxidant activity was investigated. The results showed that the optimal extraction conditions were the material-liquid ratio of 1:57 g/mL, the extraction time of 58 min, and the extraction temperature of 65 ℃. Under these conditions, the yield of polysaccharides was 7.54%±0.12%. Fourier transform infrared spectroscopy of the extracted polysaccharides exhibited a typical polysaccharide absorbance. Moreover, the half-maximal inhibitory concentrations (IC50) of polysaccharides against DPPH and ABTS+ free radicals were 1.104 and 1.408 mg/mL, respectively, indicating significant in vitro antioxidant activity. The results of this study provided a theoretical foundation for the further development and utilization of Solanum lyratum polysaccharides

Arecoline induces dual modulation of blood pressure in rat, including an initial downregulation and a subsequent upregulation

Purpose: To determine the role of arecoline in cardiovascular modulation in rats.Methods: After rats were anaesthetized with intraperitoneal urethane (1.4 g/kg body weight), saline or arecoline (at doses of 1.0, 3.0 and 10.0 mg/kg) was intraperitoneally administered, and blood pressure (BP) was continuously recorded using a physiological apparatus. Mean arterial pressure (MAP), maximum changes in MAP and reaction time due to arecoline stimulations were calculated and analyzed.Results: Arecoline induced biphasic modulation in BP, including an initial downregulation followed by a subsequent upregulation. The MAP and maximum change in MAP exhibited a concentration-dependent effect in the downregulation phase (p < 0.001 within each group), but not in the upregulation phase (p > 0.05 within each group), while BP reaction time showed a dose-dependent prolongation in both downregulation and upregulation phases (ps < 0.01 within each group). Remarkably, arecoline-induced BP downregulation more rapidly and drastically than upregulation in each arecoline group.Conclusion: These results indicate that arecoline exerts a complex effect in cardiovascular modulation that should be considered as side effects in the clinical use of arecoline and/or with the habitual chewing of areca nuts. Keywords: Arecoline, Blood pressure, Downregulation, Upregulatio

Up-Regulation of Kin17 Is Essential for Proliferation of Breast Cancer

Background: Kin17 is ubiquitously expressed at low levels in human tissue and participates in DNA replication, DNA repair and cell cycle control. Breast cancer cells are characterized by enabling replicative immortality and accumulated DNA damage. However, whether kin17 contributes to breast carcinogenesis remains unknown. Methodology/Principal Findings: In this study, we show for the first time that kin17 is an important molecule related to breast cancer. Our results show that kin17 expression was markedly increased in clinical breast tumors and was associated with tumor grade, Ki-67 expression, p53 mutation status and progesterone receptor expression, which were assessed in a clinicopathologic characteristics review. Knockdown of kin17 inhibited DNA replication and repair, blocked cell cycle progression and inhibited anchorage-independent growth, while increasing sensitivity to chemotherapy in breast cancer cells. Moreover, kin17 silencing decreased EGF-stimulated cell growth. Furthermore, overexpression of kin17 promoted DNA replication and cell proliferation in MCF-10A. Conclusions/Significance: Our findings indicate that up-regulation of kin17 is strongly associated with cellular proliferation, DNA replication, DNA damage response and breast cancer development. The increased level of kin17 was not only a consequence of immortalization but also associated with tumorigenesis. Therefore, kin17 could be a novel therapeuti

Correlation and combining ability analysis of physiological traits and some agronomic traits in maize

Combining ability information on the physiological traits in maize (Zea mays L) and the relationship between physi¬ological traits and biomass, grain yield (GY) and yield components (YC) can help maize breeders design experi¬ments for improving inbred lines and/or developing hybrids with improved GY or YC (GYYC). A six-parent diallel experiment (Griffing method 3) was conducted for combining ability and correlation analyses. The objectives of this study were to 1) study the correlation between physiological traits and biomass at seedling stage; 2) study which physiological traits at seedling stage have significant correlation with biomasses at both seedling and later growth stages and GYYCs; 3) evaluate combining ability of the physiological traits that are significantly correlated with either GY or one of the YCs. Results showed plant heights at 20 day, 40 day, and leaf area were highly corre¬lated with both dry weights of shoots and roots. All chlorophyll-related organelles were significantly correlated with only dry weights of shoots. However, dry matter at seedling stage seemed not to be related to dry matter in later growth stages. Five physiological traits (stomatal conductance, transpiration rate, net photosynthetic rate, two quantum yield related traits) at seedling stage were identified to greatly impact dry matter at later growth stages. Results also showed that 13 out of 35 physiological traits studied were significantly correlated with GYYCs. Differ¬ent germplasms for improving GYYCs could be used based on both correlation between the 13 traits and GYYCs and combining ability effects of each line for the 13 selected traits

Trap-Assisted Charge Injection into Large Bandgap Polymer Semiconductors.

The trap-assisted charge injection in polyfluorene-poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) model systems with an Al or Al/LiF cathode is investigated. We find that inserting 1.3 nm LiF increases electron and hole injections simultaneously and the increase of holes is greater than electrons. The evolution of internal interfaces within polymer light-emitting diodes is observed by transmission electron microscopy, which reveals that the introduction of LiF improves the interface stability at both the cathode (cathode/polymer) and the anode (indium tin oxide (ITO)/PEDOT:PSS). Above-mentioned experimental results have been compared to the numerical simulations with a revised Davids model and potential physical mechanisms for the trap-assisted charge injection are discussed

Theory and Experiments of Pressure-Tunable Broadband Light Emission from Self-Trapped Excitons in Metal Halide Crystals

Hydrostatic pressure has been commonly applied to tune broadband light emissions from self-trapped excitons (STE) in perovskites for producing white light and study of basic electron-phonon interactions. However, a general theory is still lacking to understand pressure-driven evolution of STE emissions. In this work we first identify a theoretical model that predicts the effect of hydrostatic pressure on STE emission spectrum, we then report the observation of extremely broadband photoluminescence emission and its wide pressure spectral tuning in 2D indirect bandgap CsPb2Br5 crystals. An excellent agreement is found between the theory and experiment on the peculiar experimental observation of STE emission with a nearly constant spectral bandwidth but linearly increasing energy with pressure below 2 GPa. Further analysis by the theory and experiment under higher pressure reveals that two types of STE are involved and respond differently to external pressure. We subsequently survey published STE emissions and discovered that most of them show a spectral blue-shift under pressure, as predicted by the theory. The identification of an appropriate theoretical model and its application to STE emission through the coordinate configuration diagram paves the way for engineering the STE emission and basic understanding of electron-phonon interaction