Effects of combined antibiotics on nitrification, bacteria and antibiotic resistance genes in activated sludge: Insights from legacy effect of antibiotics.

The effect of combined antibiotics exposure on nitrogen removal, microbial community assembly and proliferation of antibiotics resistance genes (ARGs) is a hotspot in activated sludge system. However, it is unclear that how the historical antibiotic stress affects the subsequent responses of microbes and ARGs to combined antibiotics. In this study, the effects of combined sulfamethoxazole (SMX) and trimethoprim (TMP) pollution on activated sludge under legacy of SMX or TMP stress with different doses (0.

[Historical Antibiotic Stress Changed the Effects of Sulfamethoxazole and Trimethoprim on Activated Sludge: ARGs and Potential Hosts].

The co-exposure of antibiotics has important effects on antibiotic resistance genes (ARGs) and microbial community aggregation in wastewater treatment plants (WWTPs). However, it is unclear whether differences in historical antibiotic exposure stress can determine responses of microbes and ARGs to combined antibiotics. By selecting a high concentration (30 mg·L) of sulfamethoxazole (SMX) and trimethoprim (TMP) as historical exposure stress conditions, the effects of SMX and TMP-combined pollution on ARGs, bacterial communities, and their interactions were explored in short-term experiments.

Fates of antibiotic resistance genes and bacterial/archaeal communities of activated sludge under stress of copper: Gradient increasing/decreasing exposure modes.

Effect of copper (Cu) on antibiotic resistance genes (ARGs) and bacterial/archaeal community of activated sludge under gradient increasing (0.5-10 mg/L) or decreasing exposure (10-0.5 mg/L) modes was explored.

The dissimilarity of antibiotic and quorum sensing inhibitor on activated sludge nitrification system: Microbial communities and antibiotic resistance genes.

Effects of antibiotics (azithromycin, AZM, 1-40 mg/L) and quorum sensing inhibitor (QSI, 2(5H)-furanone, 1-40 mg/L) combined pollution with environmental concentration of copper on bacterial/archaeal community and antibiotic resistance genes (ARGs) in activated sludge system were explored. QSI inhibited nitrification more obviously than AZM. AZM and QSI were synergistic inhibitions on bacterial diversity, and AZM inhibited bacterial compositions more than QSI.

Impact of ciprofloxacin and copper combined pollution on activated sludge: Abundant-rare taxa and antibiotic resistance genes.

This study aimed to explore the impacts of ciprofloxacin (CIP, 0.05-40 mg/L) and copper (3 mg/L) combined pollution on nitrification, microbial community and antibiotic resistance genes (ARGs) in activated sludge system during stress- and post-effect periods. Higher CIP concentration inhibited nitrification and an average of 50% total nitrogen removal occurred under 40 mg/L of CIP pressure.

Impacts of combined pollution under gradient increasing and gradient decreasing exposure modes on activated sludge: Microbial communities and antibiotic resistance genes.

The responses of microbial communities and antibiotic resistance genes (ARGs) to azithromycin and copper combined pollution under gradient increasing (from 0.5 to 10 mg/L) and decreasing exposure (from 10 to 0.5 mg/L) modes were investigated.

Response of microbial communities based on full-scale classification and antibiotic resistance genes to azithromycin and copper combined pollution in activated sludge nitrification laboratory mesocosms at low temperature.

This study aimed to investigate the short-term response of abundant-rare genera and antibiotic resistance genes (ARGs) to azithromycin (AZM, 0.05-40 mg/L) and copper (1 mg/L) combined pollution in activated sludge nitrification system at low temperature. Nitrification was as expected inhibited in stress- and post-effects periods under AZM concentration higher than 5 mg/L.

Multi-metabolism regulation insights into nutrients removal performance with adding heterotrophic nitrification-aerobic denitrification bacteria in tidal flow constructed wetlands.

Constructed wetlands (CWs) usually exhibit limits in functional redundancy and diversity of microbial community contributing to lower performances of nutrients removal in decentralized domestic sewage treatment. To address this quandary, heterotrophic nitrification-aerobic denitrification (HN-AD) bacteria was added in tidal flow CWs (TFCWs) developing for nitrogen (N) and phosphorus (P) removal. With addition of HN-AD bacteria, TFCWs could be setup more rapidly and obtained better removal efficiencies of 66.

Protein-bound calcium phosphate in uremic rat serum: a quantitative study.

Protein-bound calcium (prCa) constitutes about 40% of serum total calcium, in which albumin is the most dominant protein. Given the chemical interaction between calcium and phosphate (Pi), the increased serum Pi in chronic kidney disease may cause changes in the composition and structure of the prCa fraction. Here, we report the phosphate binding on the protein-bound calcium in uremic rat serum.

Pseudo-equilibrium equation of calcium phosphate precipitation from aqueous solution.

An X-ray amorphous phase is frequently present at the early stage of calcium phosphate crystallization, and the relevant solution chemistry is essential for understanding the mechanism of reaction. Here, we report a quantitative study of a series of reaction systems at pseudo-equilibrium states. We determined the composition of solutions and the quantities of the precipitate samples, and characterized the long- and short-range order of the precipitate using X-ray diffraction and synchrotron X-ray absorption near-edge structure spectroscopy, respectively.

An Approach to the Uniform Dispersion of Graphene Nanosheets in Powder Metallurgy Nickel-Based Superalloy.

In this paper, a wet-chemical based method was adopted to acquire the uniform dispersion of graphene nanosheets (GNSs) in a powder metallurgy nickel-based superalloy (FGH96) to fabricate a new GNSs reinforced FGH96 metal matrix composite. The surface of the FGH96 powder was modified using a hydrophilic surfactant named polyvinyl alcohol (PVA), which has good wettability and strong hydrogen bonding between the ⁻OH groups of PVA and oxygen groups of GNSs such as ⁻COOH, ⁻CHO, and ⁻OH. It was shown that the GNSs displayed much better dispersion uniformity on the PVA modified FGH96 powder than the unmodified one.

Ex vivo detection of calcium phosphate and calcium carbonate in rat blood serum.

The total calcium (tCa) in blood serum comprises free Ca ions (fCa), protein-bound calcium (prCa), and complexed calcium by small anions (cCa). The cCa fraction, in addition to fCa, has been indicated to have some physiological activity. However, there is little evidence for the structure of its constituents.

[Influence of intranasal instilled titanium dioxide nanoparticles on monoaminergic neurotransmitters of female mice at different exposure time].

Objective: To investigate the influence of intranasal instilling titanium dioxide (TiO2) nanoparticles on monoaminergic neurotransmitters at different-time exposure.

Methods: CD female mice were intranasally instilled three different-sized (25 nm, 80 nm and 155 nm) TiO, suspension every other day in a dose of 50 mg/kg body weight. The control group was instilled the same volume of Milli-Q water.

[Rapid analysis of methylmercury and total mercury in biological samples by ultrasonic-assisted solvent extraction coupled with inductively coupled plasma-mass spectrometry].

The analytical method for the determination of total mercury and methylmercury in biological samples was studied using ultrasonic-assisted solvent extraction coupled with inductively coupled plasma-mass spectrometry. Various extraction conditions like solvent types and concentrations, different assisted methods, and ultrasonic radiation time were optimized. Samples were digested with 6 mol x L(-1) HCl, ultrasonicated for 2 hours, extracted by organic solvent, then back-extracted by water and directly measured after dilution.

[Trends in chemical speciation of selenium in living organisms by hyphenated techniques].

In the environment and living organisms, limited concentrations and complexity of selenium compounds constitute challenges to the analytical techniques. Since their biological activities are dependent on their chemical states and structure, the key issue lies in the selective determination of the particular species of selenium, which is beneficial to clearly understanding its biochemical roles in metabolism, physiology, toxicology, nutrition, and clinical chemistry. For these purposes, the advanced analytical techniques are greatly indispensable.

[Analysis of total mercury and methylmercury concentrations in four commercially important freshwater fish species obtained from Beijing markets].

Objective: The present paper makes an attempt to evaluate the risk of mercury exposure to human by analyzing the total mercury and methylmercury concentrations of four commercially important freshwater fish species in Beijing market.

Methods: Fish samples of common carp, grass carp, bighead carp, and snakehead were purchased from Beijing market. Then their muscle, liver and gills were taken out.