Nitrogen removal and nitrous oxide emission in surface flow constructed wetlands for treating sewage treatment plant effluent: Effect of C/N ratios

© 2017 Elsevier Ltd In order to design treatment wetlands with maximal nitrogen removal and minimal nitrous oxide (N2O) emission, the effect of influent C/N ratios on nitrogen removal and N2O emission in surface flow constructed wetlands (SF CWs) for sewage treatment plant effluent treatment was investigated in this study. The results showed that nitrogen removal and N2O emission in CWs were significantly affected by C/N ratio of influent. Much higher removal efficiency of NH4+-N (98%) and TN (90%) was obtained simultaneously in SF CWs at C/N ratios of 12:1, and low N2O emission (8.2 mg/m2/d) and the percentage of N2O-N emission in TN removal (1.44%) were also observed. These results obtained in this study would be utilized to determine how N2O fluxes respond to variations in C/N ratios and to improve the sustainability of CWs for wastewater treatment

Porous structure and adsorptive properties of hide waste activated carbons prepared via potassium silicate activation

© 2014 Elsevier B.V. A novel activating agent, potassium silicate, was employed in the preparation of hide waste activated carbon. Effects of different activation temperatures and impregnation ratios on porous activated carbon evolution were evaluated by nitrogen adsorption/desorption. The BET specific surface area and pore volume of prepared activated carbon could attain 2046.12 m2/g and 1.068 cm3/g, when the process of preparation carried out at the best conditions (activation temperature of 700 °C and the impregnation ratio of 2:1). Methylene blue (MB) was selected as the adsorbate to evaluate its adsorption property. Adsorption results can be fitted well by the Langmuir isotherm, indicating the maximum monolayer adsorption capacity of MB reached to 769.23 mg/g

Nitrous oxide emission in an aerobic granulation sequencing batch airlift reactor at ambient temperatures

This study aims to investigate the nitrous oxide (N2O) emission in an aerobic granulation sequencing batch airlift reactor (SBAR) and the associated microbial community of aerobic granular sludge at ambient temperature (18±3)°C. After 48 days of operation, 1-2mm granules were obtained and excellent chemical oxygen demand (COD) and ammonium (NH4+-N) removal efficiencies were stably achieved. N2O concentration in the off gas was maximal at the beginning of the aerobic period and stabilized at a lower concentration after an initial peak. (0.60±0.17, n=3) % of the total nitrogen load to the SBAR was emitted as N2O. A dramatic change in the microbial community structure was noted between the initial seed sludge and the final mature aerobic granular sludge. Nitrosospira was identified to be the dominant ammonium oxidizing bacteria (AOB) which was attributed as the dominant source of N2O production in aerobic granular sludge by analysis of 16S rDNA sequences. © 2013 Elsevier Ltd

Comparative study on microstructure and surface properties of keratin- and lignocellulosic-based activated carbons

© 2015 Elsevier B.V. All rights reserved. The paper probed the preparation of activated carbon by potassium silicate (K2SiO3) activation from keratin waste (cowhair waste, CW) and lignocellulosic materials (Cyperus alternifolius, CA) and the comparisons of physicochemical properties of the resulting carbons. These impregnation conditions were as follows: one impregnated at room temperature for 12 h then dipped at high temperature for 30 min; the other was only impregnated at room temperature for 12 h, producing four activated carbons CWAC-1, CWAC-2, CAAC-1, and CAAC-2. The influence of activation time, K2SiO3/precursor weight ratio, and the pre-process on properties of activated carbons was discussed. The CWAC-1 produced at 700°C with the K2SiO3/precursor weight ratio of 2:1 possessed the Brunauer-Emmet-Teller (BET) surface area of 1965 m2/g and total pore volume of 1.345 cm3/g, while CAAC-1 prepared at the same conditions attained the BET surface area of 1710 m2/g and total pore volume of 0.949 cm3/g. The surface area and total pore volume of CAAC increased with the impregnation ratio. Moreover, CWAC-1, CWAC-2, CAAC-1, and CAAC-2 exhibited high portion of micropores, illustrating the role of K2SiO3. The analysis with a Fourier transform infrared spectrometer indicates that CWAC has more functional groups than CAAC, as well as CWAC-1 and CWAC-2 which possess similar functional groups

Multilayer-Assembled Microchip for Enzyme Immobilization as Reactor Toward Low-Level Protein Identification

A microchip reactor has been developed on the basis of a layer-by-layer approach for fast and sensitive digestion of proteins. The resulting peptide analysis has been carried out by matrix-assisted laser desorption ionization timeof- flight mass spectrometry (MALDI-TOF MS). Natural polysaccharides, positively charged chitosan (CS), and negatively charged hyaluronic acid (HA) were multilayerassembled onto the surface of a poly(ethylene terephthalate) (PET) microfluidic chip to form a microstructured and biocompatible network for enzyme immobilization. The construction of CS/HA assembled multilayers on the PET substrate was characterized by AFM imaging, ATRIR, and contact angle measurements. The controlled adsorption of trypsin in the multilayer membrane was monitored using a quartz crystal microbalance and an enzymatic activity assay. The maximum proteolytic velocity of the adsorbed trypsin was 600 mM/min íg, thousands of times faster than that in solution. BSA, myoglobin, and cytochrome c were used as model substrates for the tryptic digestion. The standard proteins were identified at a low femtomole per analysis at a concentration of 0.5 ng/íL with the digestion time <5s. This simple technique may offer a potential solution for low-level protein analysis

Assembly-Controlled Biocompatible Interface on a Microchip: Strategy to Highly Efficient Proteolysis

A biocompatible interface was constructed on a microchip by using the layer-by-layer (LBL) assembly of charged polysaccharides incorporating proteases for highly efficient proteolysis. The controlled assembly of natural polyelectrolytes and the enzyme-adsorption step were monitored by using a quartz-crystal microbalance and atomic force microscopy (AFM). Such a multilayer-assembled membrane provides a biocompatible interconnected network with high enzyme-loading capacity. The maximum digestion rate of the adsorbed trypsin in a microchannel was significantly accelerated to 1600 mM min

Skin flora: Differences Between People Affected by Albinism and Those with Normally Pigmented Skin in Northern Tanzania - Cross Sectional Study.

Skin flora varies from one site of the body to another. Individual's health, age and gender determine the type and the density of skin flora. A 1  cm² of the skin on the sternum was rubbed with sterile cotton swab socked in 0.9% normal saline and plated on blood agar. This was cultured at 35 °C. The bacteria were identified by culturing on MacConkey agar, coagulase test, catalase test and gram staining. Swabs were obtained from 66 individuals affected by albinism and 31 individuals with normal skin pigmentation. Those with normal skin were either relatives or staying with the individuals affected by albinism who were recruited for the study. The mean age of the 97 recruited individuals was 30.6 (SD ± 14.9) years. The mean of the colony forming units was 1580.5 per cm2. Those affected by albinism had a significantly higher mean colony forming units (1680  CFU per cm²) as compared with 453.5  CFU per cm² in those with normally pigmented skin (p = 0.023). The skin type and the severity of sun- damaged skin was significantly associated with a higher number of colony forming units (p = 0.038). Individuals affected by albinism have a higher number of colony forming units which is associated with sun- damaged skin

Loss of Let-7 Up-Regulates EZH2 in Prostate Cancer Consistent with the Acquisition of Cancer Stem Cell Signatures That Are Attenuated by BR-DIM

The emergence of castrate-resistant prostate cancer (CRPC) contributes to the high mortality of patients diagnosed with prostate cancer (PCa), which in part could be attributed to the existence and the emergence of cancer stem cells (CSCs). Recent studies have shown that deregulated expression of microRNAs (miRNAs) contributes to the initiation and progression of PCa. Among several known miRNAs, let-7 family appears to play a key role in the recurrence and progression of PCa by regulating CSCs; however, the mechanism by which let-7 family contributes to PCa aggressiveness is unclear. Enhancer of Zeste homolog 2 (EZH2), a putative target of let-7 family, was demonstrated to control stem cell function. In this study, we found loss of let-7 family with corresponding over-expression of EZH2 in human PCa tissue specimens, especially in higher Gleason grade tumors. Overexpression of let-7 by transfection of let-7 precursors decreased EZH2 expression and repressed clonogenic ability and sphere-forming capacity of PCa cells, which was consistent with inhibition of EZH2 3′UTR luciferase activity. We also found that the treatment of PCa cells with BR-DIM (formulated DIM: 3,3′-diindolylmethane by Bio Response, Boulder, CO, abbreviated as BR-DIM) up-regulated let-7 and down-regulated EZH2 expression, consistent with inhibition of self-renewal and clonogenic capacity. Moreover, BR-DIM intervention in our on-going phase II clinical trial in patients prior to radical prostatectomy showed upregulation of let-7 consistent with down-regulation of EZH2 expression in PCa tissue specimens after BR-DIM intervention. These results suggest that the loss of let-7 mediated increased expression of EZH2 contributes to PCa aggressiveness, which could be attenuated by BR-DIM treatment, and thus BR-DIM is likely to have clinical impact

Regional differences in recombination hotspots between two chicken populations

<p>Abstract</p> <p>Background</p> <p>Although several genetic linkage maps of the chicken genome have been published, the resolution of these maps is limited and does not allow the precise identification of recombination hotspots. The availability of more than 3.2 million SNPs in the chicken genome and the recent advances in high throughput genotyping techniques enabled us to increase marker density for the construction of a high-resolution linkage map of the chicken genome. This high-resolution linkage map allowed us to study recombination hotspots across the genome between two chicken populations: a purebred broiler line and a broiler × broiler cross. In total, 1,619 animals from the two different broiler populations were genotyped with 17,790 SNPs.</p> <p>Results</p> <p>The resulting linkage map comprises 13,340 SNPs. Although 360 polymorphic SNPs that had not been assigned to a known chromosome on chicken genome build WASHUC2 were included in this study, no new linkage groups were found. The resulting linkage map is composed of 31 linkage groups, with a total length of 3,054 cM for the sex-average map of the combined population. The sex-average linkage map of the purebred broiler line is 686 cM smaller than the linkage map of the broiler × broiler cross.</p> <p>Conclusions</p> <p>In this study, we present a linkage map of the chicken genome at a substantially higher resolution than previously published linkage maps. Regional differences in recombination hotspots between the two mapping populations were observed in several chromosomes near the telomere of the p arm; the sex-specific analysis revealed that these regional differences were mainly caused by female-specific recombination hotspots in the broiler × broiler cross.</p

Reduction in Phencyclidine Induced Sensorimotor Gating Deficits in the Rat Following Increased System Xc − Activity in the Medial Prefrontal Cortex

Rationale: Aspects of schizophrenia, including deficits in sensorimotor gating, have been linked to glutamate dysfunction and/or oxidative stress in the prefrontal cortex. System xc −, a cystine–glutamate antiporter, is a poorly understood mechanism that contributes to both cellular antioxidant capacity and glutamate homeostasis. Objectives: Our goal was to determine whether increased system xc − activity within the prefrontal cortex would normalize a rodent measure of sensorimotor gating. Methods: In situ hybridization was used to map messenger RNA (mRNA) expression of xCT, the active subunit of system xc −, in the prefrontal cortex. Prepulse inhibition was used to measure sensorimotor gating; deficits in prepulse inhibition were produced using phencyclidine (0.3–3 mg/kg, sc). N-Acetylcysteine (10–100 μM) and the system xc − inhibitor (S)-4-carboxyphenylglycine (CPG, 0.5 μM) were used to increase and decrease system xc − activity, respectively. The uptake of 14C-cystine into tissue punches obtained from the prefrontal cortex was used to assay system xc − activity. Results: The expression of xCT mRNA in the prefrontal cortex was most prominent in a lateral band spanning primarily the prelimbic cortex. Although phencyclidine did not alter the uptake of 14C-cystine in prefrontal cortical tissue punches, intraprefrontal cortical infusion of N-acetylcysteine (10–100 μM) significantly reduced phencyclidine- (1.5 mg/kg, sc) induced deficits in prepulse inhibition. N-Acetylcysteine was without effect when coinfused with CPG (0.5 μM), indicating an involvement of system xc −. Conclusions: These results indicate that phencyclidine disrupts sensorimotor gating through system xc − independent mechanisms, but that increasing cystine–glutamate exchange in the prefrontal cortex is sufficient to reduce behavioral deficits produced by phencyclidine