The effect of electrodialytic treatment and Na2H2EDTA addition on methanogenic activity of copper-amended anaerobic granular sludge: treatment costs and energy consumption

The effect of electrodialytic treatment in terms of a current density, pH and Na₂H₂EDTA addition on the methanogenic activity of copper-amended anaerobic granular sludge taken from the UASB reactor from paper mill was evaluated. Moreover, the specific energy consumption and simplified operational and treatment costs were calculated. Addition of Na₂H₂EDTA (at pH 7.7) to copper-amended sludge resulted in the highest microbial activity (62 mg CH₄-COD g VSS⁻¹ day⁻¹) suggesting that Na₂H₂EDTA decreased the toxic effects of copper on the methanogenic activity of the anaerobic granular sludge. The highest methane production (159 %) was also observed upon Na₂H₂EDTA addition and simultaneous electricity application (pH 7.7). The energy consumption during the treatment was 560, 840, 1400 and 1680 kW h m⁻³ at current densities of 0.23, 0.34, 0.57 and 0.69 mA cm⁻², respectively. This corresponded to a treatment costs in terms of electricity expenditure from 39.2 to 117.6 € per cubic meter of sludge.     

Problems in seawater industrial desalination processes and potential sustainable solutions: a review

Seawater desalination has significantly developed towards membrane technology than phase change process during last decade. Seawater reverse osmosis (SWRO) in general is the most familiar process due to higher water recovery and lower energy consumption compared to other available desalination processes. Despite major advancements in SWRO technology, desalination industry is still facing significant amount of practical issues. Therefore, the potentials and problems faced by current SWRO industries and essential study areas are discussed in this review for the benefit of desalination industry. It is important to consider all the following five components in SWRO process i.e. (1) intake (2) pre-treatment (3) high pressure pumping (4) membrane separation (performance of membranes and brine disposal) and (5) product quality. Development of higher corrosion resistant piping materials or coating materials, valves, and pumps is believed to be in higher research demand. Furthermore, brine management, that includes brine disposal and resource recovery need further attention. Pre-treatment sludge management and reduced cleaning in place flush volume will reduce the capital costs associated with evaporation ponds and the maintenance costs associated with disposal and transportation reducing the unit cost of water.     

A review of computational fluid dynamics applications in pressure-driven membrane filtration

Ongoing advances in computational performance and numerics have led to computational fluid dynamics (CFD) becoming a ubiquitous modelling tool. However, CFD methods have only been adopted to simulate pressure-driven membrane filtration systems relatively recently. This paper reviews various approaches to describing the behaviour of these systems using CFD, beginning with the hydrodynamics of membrane channels, including discussion of laminar, turbulent, and transition flow regimes, with reference to the effects of osmotic pressure, concentration polarisation, and cake formation. The use of CFD in describing mass transfer through the membrane itself is then discussed, followed by some concluding comments on commercial membrane simulation packages and future research directions in membrane CFD.     

Performance of suspended and attached growth MBR systems in treating high strength synthetic wastewater

The performance of laboratory-scale attached growth (AG) and suspended growth (SG) membrane bioreactors (MBRs) was evaluated in treating synthetic wastewater simulating high strength domestic wastewater. This study investigated the influence of sponge suspended carriers in AG-MBR system, occupying 15% reactor volume, on the removal of chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP), and compared it to that of SG-MBR. Results showed that the removal efficiencies of COD, TN and TP in AG-MBR were 98%, 89% and 58%, respectively as compared to 98%, 74% and 38%, respectively in SG-MBR. Improved TN removal in AG-MBR systems was primarily based on simultaneous nitrification and denitrification (SND) process. These results infer that the presence of small bio-particles having higher microbial activity and the growth of complex biomass captured within the suspended sponge carriers resulted in improved TN and TP removal in AG-MBR.     

A de novo reciprocal t(2;18) translocation with regular trisomy 21

A 4-year-old girl with Down syndrome exhibited an autosomal translocation t(2;18) in addition to trisomy 21. An evaluation of GTG-banded metaphases revealed the karyotype 47,XX,t(2;18),21 that was confirmed by using fluorescent in situ hybridization (FISH) probes. This case represents a very rare coincidence of an autosomal aneuploidy and a structural rearrangement. Her parents showed a normal chromosome complement. The translocation must have been an apparently "balanced" one as the proband presented with typical features of Down syndrome alone. The mechanism of origin of this rearrangement along with a nondisjunctional error and its significance are discussed.     

Hydrogenotrophic denitrification of synthetic aquaculture wastewater using membrane bioreactor

A hydrogenotrophic denitrification system was evaluated in removing nitrate from synthetic aquaculture wastewater for recirculation purposes. Two membrane bioreactor (MBR) systems, namely, aeration–denitrification system (ADS) and denitrification–aeration system (DAS) were studied with 50 mg/L of influent concentrations for both organic matter and nitrate nitrogen. The DAS achieved better removal efficiency of 91.4% total nitrogen (T-N) and denitrification rate of 363.7 mg/L.day at a HRT of 3 h compared to ADS. Further, there was no nitrite accumulation in the DAS effluent. The nitrite accumulation in ADS effluent was lesser when CO₂ was used as buffer rather than K₂HPO₄ and KH₂PO₄. Estimation of kinetic parameters of hydrogenotrophic bacteria indicated lesser sludge production compared to heterotrophic denitrification. In the DAS, membrane fouling was nonexistent in the aeration reactor that was used to produce the recirculating effluent. On the contrary, membrane fouling was observed in the denitrification reactor that supplied hydrogen to the mixed liquor. Thus, this study demonstrated DAS capability in maintaining the acceptable water quality appropriate for aquaculture, in which a closed recirculating system is typically used.     

Prediction of membrane fouling in MBR systems using empirically estimated specific cake resistance

The focus of this study was to empirically estimate the specific cake resistance (SCR) by the variation in shear intensity (G) in four laboratory-scale MBRs. The control reactor (MBR₀) was operated with aeration only while other MBRs (MBR₁₅₀, MBR₃₀₀ and MBR₄₅₀) were operated with aeration and mechanical mixing intensities of 150, 300 and 450 rpm, respectively. It was found that the SCR was strongly correlated (R² = 0.99) with the fouling rates in the MBRs. Moreover, the contribution of cake resistance (R_c) to the total hydraulic resistance (R_t) was predominant compared to the irreversible fouling resistance (R_f). On this basis, the cake filtration model was selected as a predictive tool for membrane fouling. This model was modified by replacing the SCR with its empirical shear intensity relationship. The modified model can predict the fouling rate for a given shear intensity (G) within 80 and 250 s⁻¹ in a MBR system.     

Urethral seam formation and hypospadias

Knowledge of the formation of the normal male urethra may elucidate the etiology of hypospadias. We describe urethral formation in the mouse, show the similarities and relevance to human urethral development, and introduce the concept of the epithelial seam formation and remodeling during urethral formation. Three mechanisms may account for epithelial seam formation: (1) epithelial-mesenchymal transformation similar to that described in the fusion of the palatal shelves, (2) apoptosis, and/or (3) tissue remodeling via cellular migration. Urethral development in the embryonic mouse (14-21 days of gestation) was compared with urethral formation in embryonic human specimens (8-16 weeks of gestation) by using histology, immunohistochemistry, and three-dimensional reconstruction. The urethra forms by fusion of the epithelial edges of the urethral folds, giving a midline epithelial seam. The epithelial seam is remodeled via cellular migration into a centrally located urethra and ventrally displaced remnant of epithelial cells. The epithelial seam is remodeled by narrowing approximately at its midpoint, with subsequent epithelial migration into the urethra or penile skin. The epithelial cells are replaced by mesenchymal cells. This remodeling seam displays a narrow band (approximately 30 microns wide) of apoptotic activity corresponding to the mesenchymal cells and not to epithelial cells. No evidence was seen of the co-expression of cytokeratin and mesenchymal markers (actin or vimentin). Urethral seam formation occurs in both the mouse and the human. Our data in the mouse support the hypothesis that seam transformation occurs via cellular migration and not by epithelial mesenchymal transformation or epithelial apoptosis. We postulate that disruption of epithelial fusion remodeling, and cellular migration leads to hypospadias.     

Mutual functional destruction of HIV-1 Vpu and host TASK-1 channel

Sequence analysis predicted significant structural homology between the HIV-1 accessory protein Vpu and the N-terminal region of TASK-1, a mammalian background K(+) channel. If the homology resulted from molecular piracy during HIV-1 evolution, these two proteins may have important functional interactions. Here we demonstrate that TASK and Vpu physically interact in cultured cells and in AIDS lymphoid tissues. The functional consequences were potentially destructive for both components: Vpu abolished TASK-1 current, while overexpressing TASK led to a marked impairment of Vpu's ability to enhance viral particle release. Further, the first 40 amino acids of TASK-1 (part of the homology to Vpu) were capable of enhancing HIV-1 particle release. This virus-host interaction may influence HIV-1/AIDS progression, as well as electrical signaling in infected host tissues.     

Duration of Cord Clamping and Neonatal Outcomes in Very Preterm Infants

Background

Delayed cord clamping (DCC, ≥30s) increases blood volume in newborns and is associated with fewer blood transfusions and short-term neonatal complications. The optimal timing of cord clamping for very preterm infants should maximize placental transfusion without interfering with stabilization and resuscitation.

Aim

We compared the effect of different durations of DCC, 30-45s vs. 60-75s, on delivery room (DR) and neonatal outcomes in preterm infants <32 weeks gestational age (GA).

Methods

This is a single-center prospective observational study. Data were collected prospectively from eligible infants from two groups: 30-45s DCC group (January 2008 to February 2011, n = 187) and 60-75s DCC group (March 2011 to April 2014, n = 166).

Results

The 60-75s DCC group compared to the 30-45s DCC group had higher hematocrits at <2 hours (49.2% vs. 47.4%, p = 0.02). In infants <28 weeks GA, the 12–36 hours hematocrit was higher in the 60-75s DCC group compared to the 30-45s DCC group (47.9% vs. 42.1%, p = 0.002). The 60-75s DCC group had reductions in DR intubation (11% vs. 22%, p = 0.004), hypothermia on admission (1% vs. 5%, p = 0.01), surfactant therapy (13% vs. 28%, p = 0.001), intubation in the first 24 hours (20% vs. 34%, p = 0.004), any intubation (27% vs. 40%, p = 0.007), and any red blood cell transfusion (20% vs. 33%, p = 0.008) during the hospitalization compared to the 30-45s DCC group. These reductions remained significant after adjusting for GA, gender and >48 hours of antenatal steroid exposure. There was no difference between the two groups in neonatal death, intraventricular hemorrhage, chronic lung disease, late onset sepsis, necrotizing enterocolitis and severe retinopathy of prematurity.

Conclusion

In this study cohort increasing DCC duration from 30-45s to 60-75s is associated with decreased hypothermia on admission, neonatal respiratory interventions and red blood cell transfusions without increase in neonatal mortality and morbidities.