A mixed sulfur-iron particles packed reactor (SFe reactor) was developed to simultaneously remove total nitrogen (TN) and total phosphorus (TP) of the secondary effluent from municipal wastewater treatment plants. Low effluent TN (<1.5 mg/L) and TP (<0.3 mg/L) concentrations were simultaneously obtained, and high TN removal rate [1.03 g N/(L·d)] and TP removal rate [0.29 g P/(L·d)] were achieved at the hydraulic retention time (HRT) of 0.13 h. Kinetic models describing denitrification were experimentally obtained, which predicted a higher denitrification rate [1.98 g N/(L·d)] of SFe reactor than that [1.58 g N/(L·d)] of sulfur alone packed reactor due to the mutual enhancement between sulfur-based autotrophic denitrification and iron-based chemical denitrification. A high TP removal obtained in SFe reactor was attributed to chemical precipitation of iron particles. Microbial community analysis based on 16S rRNA revealed that autotrophic denitrifying bacteria Thiobacillus and Sulfuricella were the dominant genus, indicating that autotrophic denitrification played important role in nitrate removal. These results indicate that sulfur and iron particles can be packed together in a single reactor to effectively remove nitrate and phosphorus.
Large-scale membrane bioreactors (MBRs) have been widely used for the municipal wastewater treatment, whose performance relies on microbial communities of activated sludge. Nevertheless, microbial functional structures in MBRs remain little understood. To gain insight into functional genes and their steering environmental factors, we adopted GeoChip, a high-throughput microarray-based tool, to examine microbial genes in four large-scale, in-operation MBRs located in Beijing, China. The results revealed substantial microbial gene heterogeneity (43.7-85.1% overlaps) among different MBRs. Mantel tests indicated that microbial nutrient cycling genes were significantly (P < 0.05) correlated to influent COD, [Formula: see text] -N, TP or sulfate, which signified the importance of microbial mediation of wastewater constituent removal. In addition, functional genes shared by all four MBRs contained a large number of genes involved in antibiotics resistance, metal resistance and organic remediation, suggesting that they were required for degradation or resistance to toxic compounds in wastewater. The linkages between microbial functional structures and environmental variables were also unveiled by the finding of hydraulic retention time, influent COD, [Formula: see text] -N, mixed liquid temperature and humic substances as major factors shaping microbial communities. Together, the results presented demonstrate the utility of GeoChip-based microarray approach in examining microbial communities of wastewater treatment plants and provide insights into the forces driving important processes of element cycling.
Apart from the abnormalities of tubal anatomy, the main concern linked to infertility is impaired tubal motility associated with hydrosalpinx, which is thought to be controlled by hormones and nerves. The objective of this study was to determine the distribution of nerve fibers in the oviduct isthmus in women with and without hydrosalpinx. Histological sections of the oviduct isthmus tissue were obtained from 18 women undergoing salpingectomy for hydrosalpinx, and from 15 women undergoing hysterectomy and salpingectomy for benign gynecologic diseases. The tissues were immunohistochemically stained for protein gene product (PGP) 9.5, protein S100, neuropeptide tyrosine (NPY), and vasoactive intestinal peptide (VIP) to reveal all nerve fibers, as well as sympathetic and parasympathetic nerve fibers, in the oviduct isthmus. We detected the presence of PGP9.5, S100, VIP, and NPY-immunoreactive nerve fibers in the oviduct isthmus in all study subjects. However, the densities of PGP9.5, S100, VIP, and NPY-immunoreactive nerve fibers in the oviduct isthmus were all significantly decreased in women with hydrosalpinx compared with those in women without hydrosalpinx (P<0.01). Our results suggest that reduced nerve fibers in the oviduct isthmus in women with hydrosalpinx compared with women without hydrosalpinx may have an important function in the mechanism of hydrosalpinx-associated infertility.
Acute pancreatitis (AP), in particular, severe acute pancreatitis (SAP), is a rare but challenging complication during pregnancy in terms of diagnosis and management. The objective of this paper is to investigate the causes and therapeutic strategies of AP in patients during the third trimester of pregnancy.
Four materials, carbon felt cube (CFC), granular graphite (GG), granular activated carbon (GAC) and granular semicoke (GS) were tested as packed anodic materials to seek a potentially practical material for microbial fuel cells (MFCs). The microbial community and its correlation with the electricity generation performance of MFCs were explored. The maximum power density was found in GAC, followed by CFC, GG and GS. In GAC and CFC packed MFCs, Geobacter was the dominating genus, while Azospira was the most populous group in GG. Results further indicated that GAC was the most favorable for Geobacter adherence and growth, and the maximum power densities had positive correlation with the total biomass and the relative abundance of Geobacter, but without apparent correlation with the microbial diversity. Due to the low content of Geobacter in GS, power generated in this system may be attributed to other microorganisms such as Synergistes, Bacteroidetes and Castellaniella.
Angiogenesis is a prerequisite for the formation and development of endometriosis. Pigment epithelium derived factor (PEDF) is a natural inhibitor of angiogenesis. We previously demonstrated a reduction of PEDF in the peritoneal fluid, serum and endometriotic lesions from women with endometriosis compared with women without endometriosis. Here, we aim to investigate the inhibitory effect of PEDF on human endometriotic cells in vivo and in vitro. We found that PEDF markedly inhibited the growth of human endometrial implants in nude mice and of ovarian endometriotic stromal cells in vitro by up-regulating PEDF expression and down-regulating vascular endothelial growth factor (VEGF) expression. Moreover, apoptotic index was significantly increased in endometriotic lesions in vivo and endometriotic stromal cells in vitro when treated with PEDF. In mice treated with PEDF, decreased microvessel density labeled by Von Willebrand factor but not by ?-Smooth Muscle Actin was observed in endometriotic lesions. And it showed no increase in PEDF expression of the ovary and uterus tissues. These findings suggest that PEDF gene therapy may be a new treatment for endometriosis.
Angiogenesis is a prerequisite for endometriotic lesion formation and development. Pigment epithelium-derived factor (PEDF) is a potential inhibitor of angiogenesis. The objective of this study was to detect PEDF immunolocalization in endometriotic lesions and the correlation with vascular endothelial growth factor (VEGF) and microvascular density (MVD) in a rat model of endometriosis. A subcutaneous endometriosis rat model was established by using auto-transplantation. Expression of PEDF, VEGF and MVD labeled by von Willebrand factor (v-WF) in endometriotic lesions and endometrial tissues was evaluated using immunohistochemical staining. We detected lower PEDF immunostaining and higher VEGF and MVD immunostaining in active lesions in a rat model of endometriosis than that in endometriosis endometrium or control endometrium (P<0.05), but no differences between endometriosis and control endometrium were found (P>0.05). In lesions, PEDF expression was negatively correlated with VEGF expression, MVD or sizes of cysts (P<0.01). On the contrary, both VEGF expression and MVD were positively correlated with lesion sizes (P<0.05). In addition, VEGF expression was positively correlated with MVD (P<0.01). Our results suggest that PEDF might be involved in the pathogenesis of endometriosis and may lead to novel treatment for this disease.
The long-term effect of set potential on oxygen reducing biocathodes was investigated in terms of electrochemical and biological characteristics. Three biocathodes were poised at 200, 60 and -100 mV vs. saturated calomel electrode (SCE) for 110 days, including the first 17 days for startup. Electrochemical analyses showed that 60 mV was the optimum potential during long-term operation. The performance of all the biocathodes kept increasing after startup, suggesting a period longer than startup time needed to make potential regulation more effective. The inherent characteristics without oxygen transfer limitation were studied. Different from short-term regulation, the amounts of biomass were similar while the specific electrochemical activity was significantly influenced by potential. Moreover, potential showed a strong selection for cathode bacteria. Clones 98% similar with an uncultured Bacteroidetes bacterium clone CG84 accounted for 75% to 80% of the sequences on the biocathodes that showed higher electrochemical activity (60 and -100 mV).
Biocathode MFCs using microorganisms as catalysts have important advantages in lowering cost and improving sustainability. Electrode materials and microbial synergy determines biocathode MFCs performance. In this study, four materials, granular activated carbon (GAC), granular semicoke (GS), granular graphite (GG) and carbon felt cube (CFC) were used as packed cathodic materials. The microbial composition on each material and its correlation with the electricity generation performance of MFCs were investigated. Results showed that different biocathode materials had an important effect on the type of microbial species in biocathode MFCs. The microbes belonging to Bacteroidetes and Proteobacteria were the dominant phyla in the four materials packed biocathode MFCs. Comamonas of Betaproteobacteria might play significant roles in electron transfer process of GAC, GS and CFC packed biocathode MFCs, while in GG packed MFC Acidovorax may be correlated with power generation. The biocathode materials also had influence on the microbial diversity and evenness, but the differences in them were not positively related to the power production.
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