High-Contrast Luminescent Immunohistochemistry Using PEGylated Lanthanide Complexes.

Immunohistochemistry (IHC) using fluorescent probes provides high resolution with multiplexing capability, but the imaging contrast is limited by the brightness of the fluorescent probe and the intrinsic autofluorescence background from tissues. Herein, we improved the contrast by high-density labeling of long-lifetime lanthanide complexes and time-gated imaging. As the large (∼280 nm) Stokes shift of lanthanide complexes effectively prevents the issue of concentration quenching, we succeeded in conjugating seven europium complexes to an eight-arm hydrophilic poly(ethylene glycol) (PEG) linker for signal amplification with improved water solubility to the level of up to 10 mg/mL. Moreover, we demonstrated that both human epidermal growth factor receptor 2 (HER2) in a formalin-fixed paraffin-embedded (FFPE) tissue section and cytokeratin 18 (CK18) in a frozen section can be resolved with the enhanced contrast by 2-fold and 3-fold, respectively. Furthermore, we show that the PEGylation of multiple lanthanide complexes is compatible with tyramide signal amplification (TSA). This work suggests new opportunities for sensitive imaging of low-abundance biomarkers in a tissue matrix.

Effects of electroflocculation/oxidation pretreatment on the fouling characteristics of ultrafiltration membranes.

In order to reduce the membrane pollution of ultrafiltration caused by natural organic matter and improve the treatment efficiency, electroflocculation/oxidation is used as the premembrane treatment method. The membrane specific flux attenuation characteristics was compared and analyzed under the conditions of direct ultrafiltration and electroflocculation/oxidation-ultrafiltration. Combined with the analysis of the reversibility of membrane fouling, the mechanism of electroflocculation/oxidation pretreatment to alleviate ultrafiltration membrane fouling was evaluated, and the membrane pore clogging model was used to fit the fouling law. The results show that, in the continuously fed filtration experiment, the electroflocculation/oxidation process involved in the pretreatment and the direct ultrafiltration membrane filtration decreased the ultrafiltration membrane flux to 79.1% and 28.5%, respectively. The reversible resistance generated by ultrafiltration and electroflocculation/oxidation-ultrafiltration processes accounted for 37.70% and 62.26% of their total pollution resistance, whereas the irreversible resistance generated accounted for 47.30% and 12.40%, respectively. Meanwhile, the direct correlation between the the flux dropped and complete clogging became less than that of the ultrafiltration process. The pretreatment significantly strengthened irreversible fouling resistance of the membrane pores. The membrane permeation flux was significantly increased after the electroflocculation/oxidation pretreatment.

Study on mitigating membrane fouling based on precursor and flocculant Alb matching in EC/O-UF system.

One of the effective ways to remove halogenated disinfection by-products (DBPs) from drinking water is the application of ultrafiltration technology. However, membrane fouling is an important factor affecting the service life and treatment effect. In this study, the electrocoagulation/oxidation-ultrafiltration (EC/O-UF) process was used to remove the precursor substance that produced DBPs, i.e. dissolved organic matters (DOMs). Operating parameters were optimized from the matching of different flocculant morphology to low concentration DOM. The degree of membrane fouling was characterized by analyzing DOMs concentration and membrane flux. The results showed that the optimal conditions for the production of Alb were: current density 10 A/m2, hydraulic retention time 10 min, and initial pH 5.0-7.0. Under these conditions, the production of flocculant Alb could reach 58-61%, 94-97% DOMs were removed by EC/O-UF.

The life cycle of micro-nano plastics in domestic sewage.

As a kind of novel pollutant, microplastics and nanoplastics have been commonly found in all regions of the world and have attracted widespread attention in recent years. Wastewater treatment plants are considered an important "source" and "sink" of micro-nano plastics pollution, so it is significant to study its transportation and fate in wastewater plants. This review summarizes the types and sources of micro-nano plastics in domestic wastewater and compares their removal efficiency and migration in different treatment processes in wastewater plants. The interlinkages and ecological risks among surface water, soil and atmospheric environments are also analyzed, providing a reference for future research on the impact of wastewater treatment plants on micro-nano plastics pollution.

Adsorption behaviour of microplastics on the heavy metal Cr(VI) before and after ageing.

As the important carriers of environmental pollutants, microplastics have a significant impact on the migration, transformation and toxicology of heavy metals. In this paper, the adsorption behavior of Cr(VI) on PE/PS/PA microplastics under UV irradiation was studied. The research results show that the adsorption capacity of original PA is the strongest, followed by PS and PE. The specific surface area of the aged microplastics increased and new functional groups were formed, so the adsorption of three microplastics for Cr(VI) was stronger than that before aging. The average saturation adsorption of Cr(VI) by PA/PS/PE increased respectively from 730.69 µg/g, 146.11 µg/g and 75.61 µg/g to 736.31 µg/g, 318.75 µg/g and 136.78 µg/g. The Langmuir and Freundlich models showed that the adsorption is more consistent with the Freundlich model, indicating that adsorption is mainly based on multi-molecular layer adsorption on non-homogeneous surfaces. In the Cu-Cr polluted water, Cu has different effects on the adsorption behavior. Cu can promote the adsorption of Cr(VI) by PE and PS, while inhibited the adsorption by PA. In addition, environmental conditions such as temperature, pH and dissolved organic matter also have significant effects on adsorption behavior. Mechanistic analysis confirmed that electrostatic interaction plays an important role. Secondly, based on the surface physicochemical properties of the microplastics, surface complexation and van der Waals forces also significantly enhance the adsorption of Cr(VI) on the aged microplastics.

PEGylated nano-Rehmannia glutinosa polysaccharide induces potent adaptive immunity against Bordetella bronchiseptica.

Vaccines, in many cases, stimulate only too weak immunogenicity to prevent infection. Therefore, adjuvants are required during their preparation to boost the immune response. We herein developed a PEGylated nano-adjuvant based on Rehmannia glutinosa polysaccharide (RGP). The addition of PEG layer exhibits enhanced immune performance of the nano-RGP. Stimulation of dendritic cells (DCs) with PEGylated nano-RGP (pRL) led to increased proliferation and cytokine production (IL-6, IL-12, IL-1ß and TNF-α). The pRL was internalized into DCs via a rapid and efficient method. The mice immunized with pRL exhibited enhanced antigen-specific serum IgG and Th1-(IFN-γ), Th2-(IL-4), and Th17-(IL-17, IL-6) cytokine production, contributing to a good anti-infection performance. Furthermore, the pRL could effectively deliver the antigen to the lymph nodes (LNs), activate DC in the LN and produce enhanced CD4+and CD8+ T-cells-derived memory (CD44high CD62Lhigh), and effector (CD44high CD62Llow) as well as functional phenotypes. Our results revealed that pRL can act as a promising adjuvant with targeted delivery of antigen due to its effective activation and robust adaptive immunity induction of DCs.

Biodegradability enhancement of hydrolyzed polyacrylamide wastewater by a combined Fenton-SBR treatment process.

An efficient way to solve the environmental pollution deriving from hydrolyzed polyacrylamide (HPAM)-containing drilling wastewater is urgent. This work adopted a novel method coupling Fenton oxidation with sequencing batch reactor (SBR) to treat gas-field drilling wastewater successively. This Fenton-SBR process reduced COD, HPAM, NH4+-N and total phosphorus (TP) concentrations of drilling wastewater by 98.35%, 87.58%, 94.50% and 93.52%, respectively. While simulated HPAM wastewater with similar HPAM concentration to Fenton-oxidized drilling wastewater was treated only by biological process, and the COD and HPAM removal efficiencies reached 78.26% and 62.95%. The result indicates that the biodegradability of the drilling wastewater was enhanced after Fenton oxidation. Moreover, the analysis on microbial community structure indicates the dominant bacteria in treated drilling wastewater were different from that in treated simulated-wastewater. It can be considered the Fenton-SBR process possesses potential to be applied to treating the drilling wastewater.

Experimental study on denitrification using coated electrode of immobilized denitrifying bacteria.

OBJECTIVE: To develop a coated electrode of immobilized denitrificants and to evaluate the performance of a bioelectrochemical reactor to enhance and control denitrification. METHODS: Denitrifying bacteria were developed by batch incubation and immobilized with polyvinyl alcohol (PVA) on the surface of activated carbon fiber (ACF) to make a coated electrode. Then the coated electrode (cathode) and graphite electrode (anode) were transferred to the reactor to reduce nitrate. RESULTS: After acclimated to the mixtrophic and autotrophic denitrification stages, the denitrifying bacteria could use hydrogen as an electron donor to reduce nitrate. When the initial nitrate concentration was 30.2 mg NO3- -N / L, the denitrification efficiency was 57.3% at an applied electric current of 15 mA and a hydraulic retention time (HRT) of 12 hours. Correspondingly, the current density was 0.083 mA/cm2. The nitrate removal rate of the reactor was 34.4 g NO3- -N/m3 x d, and the surface area loading was 1.34 g NO3- -N / m2 x d. CONCLUSION: The coated electrode may keep high quantity of biomass, thus achieving a high denitrification rate. Denitrification efficiencies are related to HRT, current density, oxidation reduction potential (ORP), dissolved oxygen (DO), pH value, and temperature.

Rapeseed oil and ginseng saponins work synergistically to enhance Th1 and Th2 immune responses induced by the foot-and-mouth disease vaccine.

Previous investigations demonstrated that saponins isolated from the root of Panax ginseng C. A. Meyer (i.e., ginseng root saponin [GS-R]) had adjuvant activity. In the present study, the combined effects of rapeseed oil (RO) and GS-R on the immune responses elicited by foot-and-mouth disease (FMD) vaccine were investigated by measuring FMD virus (FMDV)-specific antibody levels, cytokine levels, lymphocyte proliferation, and long-lived IgG-secreting plasma cells from bone marrow in a mouse model. The results indicated that RO in combination with GS-R significantly enhanced serum IgG and isotype concentrations, gamma interferon (IFN-γ) and interleukin 5 (IL-5) levels, splenocyte proliferative responses to stimulations with concanavalin A (ConA), lipopolysaccharide (LPS), and FMDV antigen, and the numbers of IgG-secreting plasma cells in the bone marrow, suggesting that RO/GS-R enhanced both Th1 and Th2 immune responses. In addition, no significant difference was found between RO/GS-R and the commercial adjuvant oil ISA 206 in the promotion of FMD vaccine-induced immune responses. Considering the vegetable origin of RO and GS-R and the potent adjuvant activity, RO/GS-R should be studied further for the development of veterinary vaccines, especially for use in food animals in order to promote food safety.