Development and Evaluation of Cucurbitacin B Microemulsion: the Effect of Oil Phase and Aqueous Phase on Drug Percutaneous Absorption Based on ATR-FTIR Spectroscopy and Molecular Modeling.

The present study aimed to develop a cucurbitacin B microemulsion (CuB-ME) and investigate the mechanism of the enhanced drug skin absorption at the molecular level. Firstly, the pseudo-ternary phase diagrams were developed to evaluate the effect of composition on microemulsion properties systematically. The formulation composition types and ratios of oil phase, surfactant, co-surfactant, and aqueous phase were optimized by an in vitro skin permeation experiment, and the optimized formula was confirmed with the pharmacodynamics study. Furthermore, the molecular mechanism of enhanced skin permeation was investigated using ATR-FTIR and molecular modeling. As a result, the optimized CuB-ME formulation was composed of Azone:Tween 80:ethanol:water = 2.5:16.9:5.6:75.0 (w/w/w/w). The oil phase improved skin permeation by disordering the stratum corneum intercellular liquid, while the aqueous phase impacted the particle size of the microemulsion and permeability coefficient of the drug. Besides, the hydration state of skin lipid also enhanced drug permeation by the interaction of water and the polar head of ceramide. The in vitro skin permeation amount was 45.47 ± 10.39 µg/cm2, and no significant skin irritation was observed. The pharmacodynamics study demonstrated that CuB-ME had a significant therapeutic effect on the animal tumor model. In conclusion, the CuB-ME was developed successfully and the effect of the oil phase and aqueous phase on drug skin permeation was clarified at the molecular level.

Study the biocatalyzing effect and mechanism of cellulose acetate immobilized redox mediators technology (CE-RM) on nitrite denitrification.

The biocatalyzing effect of a novel cellulose acetate immobilized redox mediators technology (CE-RM) on nitrite denitrification process was studied with anthraquinone, 1,8-dichloroanthraquinone, 1,5-dichloroanthraquinone and 1,4,5,8-tetrachloroanthraquinone. The results showed that the immobilized 1,4,5,8-tetrachloroanthraquinone presented the best biocatalyzed effect which increased nitrite denitrification rate to 2.3-fold with 12 mmol/L 1,4,5,8-tetrachloroanthraquinone. The unequal biocatalyzing effect was due to the quantity and position of -Cl substituent in anthraquinone-structure. Moreover, the nitrite denitrification rate was increased with the oxidation reduction potential (ORP) values becoming more negative during the biocatalyzing process. The stabilized ORP value with 12 mmol/L immobilized 1,4,5,8-tetrachloroanthraquinone were 81 mV lower than the control. At the same time, the more OH(-) was produced with the higher nitrite removal rate achieved in the nitrite denitrification process. In addition, a positive linear correlation was found between the nitrite removal reaction constants k [gNO2(-)-N/(gVSS d)] and immobilized 1,4,5,8-tetrachloroanthraquinone concentration (C1,4,5,8-tetrachloroanthraquinone), which was k = 1.8443 C1,4,5,8-tetrachloroanthraquinone + 33.75(R(2) = 0.9411). The initial nitrite concentration of 179 mgNO2(-)-N/L resulted in the maximum nitrite removal rate, which was 6.526[gNO2(-)-N/(gVSS d)]. These results show that the application of cellulose acetate immobilized redox mediators (CE-RM) can be valuable for increasing nitrite denitrification rate.

Electroactive properties of EABs in response to long-term exposure to polystyrene microplastics/nanoplastics and the underlying adaptive mechanisms.

Given widespread presence of polystyrene (PS) microplastics/nanoplastics (MPs/NPs), the electroactive responses and adaptation mechanisms of electroactive biofilms (EABs) exposed long-term to PS-containing aquatic environments remain unclear. Therefore, this study investigated the impacts of PS MPs/NPs on electroactivity of EABs. Results found that EABs exhibited delayed formation upon initially exposure but displayed an increased maximum current density (Imax) after subsequent exposure for up to 55 days. Notably, EABs exposure to NH2PS NPs (EAB-NH2PSNPs) demonstrated a 50% higher Imax than the control, along with a 17.84% increase in viability and a 58.10% increase in biomass. The cytochrome c (c-Cyts) content in EAB-NH2PSNPs rose by 178.35%, benefiting the extracellular electron transfer (EET) of EABs. Moreover, bacterial community assembly indicated the relative abundance of electroactive bacteria increased to 87.56% in EAB-NH2PSNPs. The adaptability mechanisms of EABs under prolonged exposure to PS MPs/NPs predominantly operate by adjusting viability, EET, and bacterial community assembly, which were further confirmed a positive correlation with Imax through structural equation model. These findings provide deeper insights into long-term effects and mechanisms of MPs/NPs on the electroactive properties of EABs and even functional microorganisms in aquatic ecosystems.

Multifaceted synergistic facilitation mechanism of conductive polymers in promoting selenite bioreduction and biological detoxification.

Here, polypyrrole (PPY) was first used to the bioreduction of toxic selenite, while the acceleration effect and mechanism were explored. Experiment results suggested that PPY could enhance the selenite bioreduction from 0.42 to 1.04 mg/(L·h). The tests of electrochemical analysis and cytochrome c (cyt-c) content confirmed that PPY promoted the intracellular/intracellular electron transfer of Shewanella oneidensis·MR-1 in selenite bioreduction process. The enhancement of metabolic activity by PPY contributed to biological detoxification, which was manifested in the increased extracellular polymeric substances (EPS), adenosine triphosphate (ATP), electron transfer system activity (ETSA), membrane permeability and enzyme activity. Transcriptome analysis of DEGs, KEGG pathway enrichment and GO functional classification verified that the environmental adaptability of Shewanella oneidensis·MR-1 was enhanced with the addition of PPY. The transmission electron microscopy (TEM) images indicated that PPY promoted the biosynthesis of selenium nanoparticles (SeNPs), which was beneficial to reduce cell damage. Combined with the above results, a multifaceted synergistic facilitation mechanism based on "conductive cross-linking network" was elaborated from electron transfer, microbial metabolism and environmental adaptability. This study shed light the effect of conductive polymers (CPs) on selenite bioreduction and provided new insights into the bioremediation of toxic pollutants.

Bioinspired facilitation of intrinsically conductive polymers: Mediating intra/extracellular electron transfer and microbial metabolism in denitrification.

Intrinsically conductive polymers, polyaniline and polyaniline sulfonate (PASAni) were used to explore their effect on denitrification. Denitrification was accelerated 1.90 times by 2 mM PASAni and the possible mechanisms were mainly attributed to the accelerated electron transfer and the enhanced microbial metabolism activity. Intracellular electron transfer was accelerated by PASAni and the acceleration sites were from NADH to coenzyme Q (CoQ), quinone loop, from Complex II to CoQ and from QH2 to Cyt. c1. Extracellular electron transfer was accelerated because PASAni promoted more secretion of redox species and PASAni embedded in extracellular polymeric substance (EPS). Moreover, PASAni itselfprovided more electron transfer pathways as redox species. Microbial metabolism activity was also enhanced by PASAni, which was reflected in the increased nitrate/nitrite reductase activity (236.13/155.43%), electron transfer system activity (112.49%), adenosine triphosphate level (133.41%) and EPS content (189.06%). Besides, the enriched Proteobacteria in PASAni supplement system was also conducive to denitrification. This work provided fundamental information for conductive polymers mediating microbial electron transfer and enhancing contaminants biotransformation.

Dynamic changes in the intestinal microbial community of two time-aged soils under combined cadmium and ciprofloxacin contaminated conditions.

The effects of combined contaminated soils containing cadmium (Cd) and ciprofloxacin (CIP) on the human gut microbiota are demonstrated using an in vitro test. Uncontaminated soil samples were artificially polluted with Cd and CIP using three different treatments (CK: 0 mg·kg-1; CIPI: 5 mg·kg-1, CIPII: 25 mg·kg-1, and Cd: 80 mg·kg-1). An experiment was performed to investigate the effect of Cd and CIP on the human colon microbiota using two aging times (D30: Day 30; D60: Day 60), and then the method of high-throughput 16S rRNA gene sequencing was used. In this study, we observed five phyla: Proteobacteria, Firmicutes, Synergistetes, Bacteroidetes, and Actinobacteria in colon microbial community. In addition, our results indicated that the relative abundances of the gut bacteria varied at the phylum level. Nevertheless, a slight decline in the relative abundance of Bacteroidetes among all the sets (compared to the D30-CK + Cd set) was revealed, and the lowest decline percentage of 90% was observed in the D60-CIPI + Cd set. Our results validated that the relative abundance of Rhodococcus increased with an increase in the CIP concentration in D30. In addition, this may disrupt normal physiological functions of the intestine after exposure to contaminated soil via the mouth. This study provides a theoretical basis for human risk assessment of oral exposure to Cd and CIP contaminated soils.

Zeolite powder based polyurethane sponges as biocarriers in moving bed biofilm reactor for improving nitrogen removal of municipal wastewater.

This study aims to enhance nitrogen removal efficiency of a moving bed biofilm reactor (MBBR) by developing a new MBBR with zeolite powder-based polyurethane sponges as biocarriers (Z-MBBR). Results indicated the total nitrogen (TN) removal efficiency and simultaneous nitrification and denitrification (SND) performance in Z-MBBR were nearly 10% higher than those in the conventional MBBR with sponges as biocarriers (S-MBBR). About 84.2 ±â€¯4.8% of TN was removed in Z-MBBR compared to 75.1 ±â€¯6.8% in S-MBBR. Correspondingly, the SND performance in Z-MBBR and S-MBBR was 90.7 ±â€¯4.1% and 81.7 ±â€¯6.5%, respectively. The amount of biofilm attached to new biocarriers (0.470 ±â€¯0.131 g/g carrier) was 1.3 times more than that of sponge carriers (0.355 ±â€¯0.099 g/g carrier). Based on the microelectrode measurements and microbial community analysis, more denitrifying bacteria existed in the Z-MBBR system, and this can improve the SND performance. Consequently, this new Z-MBBR can be a promising option for a hybrid treatment system to better nitrogen removal from wastewater.

Specific approach for membrane fouling control and better treatment performance of an anaerobic submerged membrane bioreactor.

This paper investigated a strategy to minimize membrane fouling and increase treatment efficiency through an investigation of a specific approach by adding sponges into a conventional submerged anaerobic membrane bioreactor (CAnSMBR). During the operation, the protein-based soluble microbial products as the main factor affecting the membrane fouling could be reduced by sponge addition in the CAnSMBR (SAnSMBR). Furthermore, reducing HRT from 18 h to 12 h could shorten the membrane fouling cycle to 62% and 87% in CAnSMBR and SAnSMBR, respectively. At the initial of COD/NO3 ratio ranges from 5 to 4, only 88% of nitrogen in CAnSMBR was removed, while the SAnSMBR could remove more than 90%. TOC removal efficiency could reach more than 95% under a good stirring scenario. It is evident that the SAnSMBR is a promising solution for improving overall CAnSMBR performance and substantially mitigating membrane fouling.

Rapid start-up of the anammox process: Effects of five different sludge extracellular polymeric substances on the activity of anammox bacteria.

This study investigated the rapid start-up of the anaerobic ammonium oxidation (anammox) strategy by inoculating different biomass ratios of denitrifying granular sludge and anammox bacteria. The results demonstrated that two reactors (R1 and R2) were rapidly and successfully started-up on days 25 and 28, respectively, with nitrogen removal rates (NRRs) of 0.70kg/(m(3)·d) and 0.72kg/(m(3)·d) at biomass ratios of 10:1 (R1) and 50:1 (R2). The explanation for rapid start-up was found by examining the effect of five different sludge extracellular polymeric substances (EPS) on the activity of anammox bacteria in the batch experiments. Batch experiments results first demonstrated that the denitrification sludge EPS (DS-EPS) enhanced the anammox bacteria activity the most, and NO2(-)-N, NH4(+)-N removal rates were 1.88- and 1.53-fold higher than the control with optimal DS-EPS volume of 10mL. The rapid start-up strategy makes possible the application of anammox to practical engineering.

[Preparation and Characterization of Quinone Functional Polymer Biocarrier (PET-AQS) for Biodenitrification Catalysis].

Anthraquinone sodium sulfonate (AQS) was immobilized on polyethylene terephthalate (PET) by chemical synthesis, forming quinone functional polymer biocarrier (PET-AQS), and its characteristics in biodenitrification catalysis were analyzed. Quinone group was demonstrated to be successfully immobilized on the surface of the polymer and the concentration of immobilized quinone was 0.140 6 mmol x g(-1) by Attenuated Total Reflectance Spectrometry (ATR-IR) and Energy Dispersive Spectrometry (EDS). The PET-AQS could accelerate biodenitrification. The relationship between the denitrification rate constant (K(x)) and the PET-AQS concentration (C(PET-AQS)) obeyed the pseudo-zero order kinetics. After ten rounds of recycling in the biodenitrification system with approximately 0.056 2 mmol quinone, the denitrification rate was kept at more than 1.2 times of the blank system. This indicated that PET-AQS exhibited a good operational stability and was beneficial to practical application.

[Preparation and application of the quinonyl chloromethylation polystyrene in biological treatment of wastewater].

The technology of non-water-soluble mediator anaerobic biological catalysis has attracted more and more attention in the field of environment technology. In this study, five kinds of quinonly compounds were grafted on the chloromethylation polystyrene macromolecular carrier by Friedel-Crafts reaction. Reaction factors of temperature and molar ratio for the 1,4-naphthoquinone grafting carrier were optimized, and the optimal temperature was 78 degreesC while the optimal molar ratio of 1, 4-naphthoquinone and chloromethylation polystyrene was 2: 1. Fourier infrared spectrum analysis confirmed that the quinone groups were successfully grafted on the macromolecular backbone chloromethylation polystyrene. Catalysis using the five kinds of quinonly materials as non-water-soluble redox mediators enhanced the biological denitrification rate and the decoloration of azo dyes, meanwhile these materials showed good reusability in the biodegradation of azo dye. This study developed a new method for the preparation of quinonly materials and revealed a new field in the technology of mediator catalysis.

Biological catalyzed denitrification by a functional electropolymerization biocarrier modified by redox mediator.

Electropolymerization biocarriers were prepared by the electropolymerization of polypyrrole (PPy) on an active carbon felt (ACF) electrode using doping anions anthraquinone-2-sulfonate (AQS) or Na(2)SO(4). The functional electropolymerization biocarrier (ACF/PPy/AQS) with AQS was used as an immobilized redox mediator for the denitrification process. The characteristics of the electropolymerization biocarriers were analyzed by scanning electron microscope, elemental analyses, Fourier transform infrared (FTIR) spectroscopy and Raman spectroscopy. The results suggested that the denitrification efficiency increased nearly 1.5-fold with ACF/PPy/AQS (0.04 mmol L(-1) AQS) compared to the control. A linear correlation was found for the k value and the AQS concentration (C(AQS)), which was k=624.71C(AQS)+83.87 (R(2)=0.9893). The ORP value stabilized around -200 mV for the denitrification process with ACF/PPy/AQS, which was -25 mV lower than that with ACF/PPy/Na(2)SO(4). Repeated-batch operations indicated that the denitrification efficiency with ACF/PPy/AQS maintained over 90% of the original value and exhibited better catalytic activity and durability.