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Trends in artificial sweetener consumption: a 7-year wastewater-based epidemiology study in Queensland, Australia
No full textA 7-year temporal trend study of artificial sweetener consumption was performed by determining per capital mass loads in 293 influent wastewater samples collected from a wastewater treatment plant in Australia between 2012 and 2018. Population-weighted per capita mass loads of the four detected artificial sweeteners ranged from 2.4 ± 0.8 mg d p for saccharin to 7.8 ± 2.0 mg d p for acesulfame over the study period. Negligible intra-week fluctuations were observed, however the consumption of acesulfame was seen to be significantly influenced by season with the highest consumption in summer. The consumption of sucralose and saccharin significantly increased with an annual increase rate of 10% and 6.0%. Cyclamate consumption declined over the same period with average annual decrease rate of 11%, which agrees with data from market surveys. Sucrose equivalence of total artificial sweeteners consumption showed an increase between 2012 and 2016, then decreased in 2018. This is the first long-term trend study of artificial sweetener consumption by wastewater analysis and highlights the feasibility to quantitatively measure artificial sweeter consumption over time
A novel lapping process for single-crystal sapphire using hybrid nanoparticle suspensions
No full textSingle-crystal sapphire is an important material with increasingly more widespread applications in optics, semiconductor and laser-related devices. However, its high hardness and brittleness have posed significant challenges for the efficient machining of sapphire with a satisfactory surface integrity. In this work, a new lapping process was developed for sapphire using a novel suspension that was made by dimensionally integrating alumina (AlO) nanoparticles with graphene oxide (GO) nanosheets in pure water. The performance of the AlO/GO hybrid nanosuspensions in the lapping of sapphire was systematically investigated using commercial diamond suspensions as the benchmarks. The multidisciplinary science involved in the new lapping process was unveiled. The use of the hybrid nanosuspensions during lapping enabled the generation of an oxide layer on the sapphire surface that was softer than its pristine substrate. This process thus simultaneously improved the removal efficiency and enhanced the surface quality, in comparison to conventional lapping
Arsenic trioxide-increased MDCK cells proliferation requires activator protein 1-mediated increase of the sodium/proton exchanger 1 activity
No full textThe release of protons (H) occurs via the Na/H exchanger isoform 1 (NHE1) leading to a stable intracellular pH (pHi) in MDCK cells. Chronic intake of arsenic trioxide (ATO), in the drinking water, associated with higher morbidity and mortality in neoplastic tissues. ATO increased NHE1 expression and activity, resulting in intracellular alkalization and higher MDCK cells proliferation. Since the pro-proliferative transcription factor activator protein 1 (AP-1) gets activated by al alkaline intracellular pH, a phenomenon paralleled by higher NHEs activity, we asked whether ATO-increased MDCK cells proliferation involves AP-1–dependent NHE1 activation. Cells were exposed (48 h) to ATO (0.05 μmol/L), SR11302 (1 μmol/L, AP-1 inhibitor), HOE-694 (100 nmol/L, NHE1 inhibitor) and EIPA (50 μmol/L, NHE1/NHE3 inhibitor) in the presence of S3226 (10 μmol/L, NHE3 inhibitor), concanamycin A (0.1 μmol/L, V-ATPases inhibitor), and Schering (10 μmol/L, H/K-ATPase inhibitor). [H]Thymidine incorporation, cell counting, wound healing assay, and AP-1 activity were determined. The pHi was measured in cells pre-loaded (10 min) with 2,7-bicarboxyethyl-5,6-carboxyfluorescein acetoxymethyl ester (12 mmol/L) and exposed to NHCl (20 mmol/L). Basal pHi and recovery rate (dpHi/dt), intracellular buffer capacity (βi) and H flux (J) were determined. NHE1 protein abundance was measured by Western blotting and immunofluorescence. ATO increased the cell growth (1.5 fold), basal pHi (0.4 pHi units), dpHi/dt (1.8 fold), J (1.4 fold), AP-1 activity and NHE1 protein abundance (1.3 fold). ATO also increased (1.5 fold) the nuclear/perinuclear NHE1 immunosignal. SR11302 and HOE-694 blocked ATO effects. Thus, ATO-increased proliferation resulted from AP-1–dependent NHE1 activation in MDCK cells
An investigation into the long-term binding and uptake of PFOS, PFOA and PFHxS in soil – plant systems
No full textThis study investigated the potential aging and plant bioaccumulation of three perfluoroalkyl acids (PFAAs), perfluorosulphonic acid (PFOS), perfluorooctanoic acid (PFOA) and perfluorohexanesulphonic acid (PFHxS) in 20 soils over a six-month period. Sorption coefficients (Log Kd) ranged from 0.13–1.28 for PFHxS, 0.17–1.06 for PFOA and 0.98–2.03 for PFOS, respectively, and bioaccumulation factors (Log BAFs) ranged from 0.29–1.24, 0.22–1.46 and 0.05–0.65 for PFHxS, PFOA and PFOS, respectively. Over the six-month period, Kd values significantly increased for PFHxS and PFOA but the magnitude of the increase was very small and did not translate into differences in plant PFAA-concentrations between aged and freshly spiked treatments. The Kd and BAF values were modelled by multiple linear regression (MLR) to soil physico-chemical properties and by partial least squares regression to soil spectra acquired by mid-infrared spectroscopy (DRIFT−PLSR). Modelling of each PFAA was influenced by different soil properties, including organic carbon, pH, CEC, exchangeable cations (Ca2+, Mg2+, Na+ and K+) and oxalate extractable Al. BAF values were not strongly correlated to any soil property but were inversely correlated to Kd values. Our results indicate that limited aging occurred in these soils over the six-month period
Uncovering the roles of LaB6-nanoparticle inoculant in the AlSi10Mg alloy fabricated via selective laser melting
No full textThe effects of inoculation treatment with LaB6 nanoparticles (0–2 wt% additions) on the microstructural evolution and mechanical performance in a selective laser melted AlSi10Mg alloy were comprehensively investigated. The addition of 0.2–0.5 wt% LaB6 nanoparticles was identified to be optimal to achieve substantial grain refinement, microstructural homogeneity and thus remediation in the mechanical property anisotropy in the AlSi10Mg alloy. The substantial grain refinement was attributed to the coherent Al/LaB6 interfaces, which facilitated the heterogeneous nucleation of Al on the LaB6 nanoparticles during solidification. Increasing the LaB6 addition up to 2 wt% only marginally further refined the equiaxed grains, which can be understood in terms of the concept of nucleation free zone formed in the liquid at front of the growing solid-liquid interfaces. The LaB6 nanoparticles within the nucleation free zone could not be activated to be nucleants for α-Al. As a result, random orientation relationships between LaB6 nanoparticles within the nucleation free zone and the Al matrix were determined. Those excessive LaB6 nanoparticles weakened the melt pool boundaries, and therefore deteriorated the longitudinal ductility of the SLMed AlSi10Mg alloy
Cold-start NOx emissions: Diesel and waste lubricating oil as a fuel additive
No full textNOx emissions from diesel engines are a concern from both environmental and health perspectives. Recently this attention has targeted cold-start emissions highlighting that emission after-treatment systems are not effective in this period. Using a 6-cylinder, turbocharged, common-rail diesel engine, the current research investigates NOx emissions during cold-start using different engine performance parameters. In addition, it studies the influence of waste lubricating oil on NOx emissions introducing it as a fuel additive (1 and 5% by volume). To interpret the NOx formation, this study evaluates different parameters: exhaust gas temperature, engine oil temperature, engine coolant temperature, start of injection/combustion, in-cylinder pressure, heat release rate, maximum in-cylinder pressure and maximum rate of pressure rise. This study clarified how cold-start NOx increases as the engine is warming up while in general cold-start NOx is higher than hot-start. Results showed that in comparison with warmed up condition, during cold-start NOx, maximum in-cylinder pressure and maximum rate of pressure rise were higher; while start of injection, start of combustion and ignition delay were lower. During cold-start increased engine temperature was associated with decreasing maximum rate of pressure rise and peak apparent heat release rate. During cold-start NOx increased with temperature and it dropped sharply due to the delayed start of injection. This study also showed that using waste lubricating oil decreased NOx and maximum rate of pressure rise; and increased maximum in-cylinder pressure. NOx had a direct correlation with the maximum rate of pressure rise; and an inverse correlation with the maximum in-cylinder pressure
Transition of microbial communities and degradation pathways in anaerobic digestion at decreasing retention time
No full textTuning of operational variables is a common practice to control the anaerobic digestion process and, in advanced applications, to promote the accumulation of fermentation products. However, process variables are interrelated. In this study, the hydraulic retention time (HRT) was decoupled from the organic loading rate (OLR) in order to isolate the effect of HRT as a selective pressure on: process performance, metabolic rates (hydrolytic, acetogenic, and methanogenic) and the microbial community. Four mesophilic anaerobic digesters were subjected to a sequential decrease in HRT from 15 to 8, 4 and 2 days while keeping the OLR constant at chemical oxygen demand of 1 gCOD L d. The results showed that HRT alone was insufficient to washout methanogens from the digesters, which in turn prevented the accumulation of volatile fatty acids (VFA). Methanosaeta was the dominant genus in the four digesters at all HRTs. Metabolic rates showed that process performance was controlled by hydrolysis, with a clear shift in acetogenic rates, from butyrate and propionate degradation to ethanol degradation at 4 and 2d HRT. The change in acetogenic pathways was attributed to a shift in the fermentation pathways co-current with changes in fermentative bacteria. At 2d HRT, biofilm was formed on the walls and paddles of the digesters, probably as a survival strategy. Most of the taxa in the biofilm were also present in the digester media. Overall, it is the combination of HRT with other operational parameters which promotes the washout of methanogens and the accumulation of VFA
Toluene diisocyanate-induced inflammation and airway remodeling involves autophagy in human bronchial epithelial cells
No full textToluene-diisocyanate (TDI) is one of the main causes of occupational asthma. To study the role of autophagy in TDI-induced airway inflammation and airway remodeling in bronchial airway epithelial (16HBE) cells. We treated 16HBE cells with TDI-human serum albumin (TDI-HSA) conjugate to observe reactive oxygen species (ROS) release, autophagy activation, airway inflammation and airway remodeling. 3-Methyladenine (3-MA) and Rapamycin (Rapa) intervention were used to explore the effects of autophagy on inflammatory response and protein expression related to airway remodeling in 16HBE cells treated with TDI-HSA. Experimental results suggested that various concentrations of TDI-HSA (0, 40, 80 and 120 μg/mL) increased the release of ROS and the expression of Nrf2, activated autophagy and increased the expression of AMPK, Beclin-1, LC3 and decreased the expression of p62, promoted the levels of IL-5, IL-6 and IL-8 in 16HBE cells. Results also showed that E-cadherin expression decreased but an increase was observed in α-SMA and MMP-9 in the TDI-HSA group. The treatment of TDI-HSA combined with Rapa aggravated the above reaction whereas the inverse was true for TDI-HSA combined with 3-MA. These results indicated that autophagy is involved in TDI-induced airway inflammation and airway remodeling as a positive regulatory mechanism, inhibiting autophagy can significantly alleviate the TDI-induced inflammatory response and attenuate airway remodeling protein expression in 16HBE cells
Peer-to-peer energy systems for connected communities: a review of recent advances and emerging challenges
No full textAfter a century of relative stability in the electricity industry, extensive deployment of distributed energy resources and recent advances in computation and communication technologies have changed the nature of how we consume, trade, and apply energy. The power system is facing a transition from its traditional hierarchical structure to a more decentralized model by introducing new energy distribution models such as peer-to-peer (P2P) sharing for connected communities. The proven effectiveness of P2P sharing in benefiting both prosumers and the grid has been demonstrated in many studies and pilot projects. However, there is still no extensive implementation of such sharing models in today’s electricity markets. This paper aims to shed some light on this gap through a comprehensive overview of recent advances in the P2P energy system and an insightful discussion of the challenges that need to be addressed in order to establish P2P sharing as a viable energy management option in today’s electricity market. To this end, in this article, we provide some background on different aspects of P2P sharing. Then, we discuss advances in P2P sharing through a systematic domain-based classification. We also review different pilot projects on P2P sharing across the globe. Finally, we identify and discuss a number of challenges that need to be addressed for scaling up P2P sharing in electricity markets followed by concluding remarks at the end of the paper
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