Preparation of Novel Layered High Entropy Bismuth-Based Materials and their Photocatalytic Degradation Mechanism.

We prepared BiOCl, BiO(ClBr), BiO(ClBrI), and BiO[ClBrI(CO3)0.5] materials using a simple coprecipitation method. It was found that adjusting the number of anions in the anion layer was conducive to adjusting the band structure of BiOX and could effectively promote the migration and separation of photogenerated carriers, thus improving the photocatalytic activity. We first selected methyl orange (MO) as the study pollutant and compared it with BiOCl, BiO(ClBr), and BiO(ClBrI). The first-order kinetic constants of MO degradation by BiO[ClBrI(CO3)0.5] increased by 90.3, 33.9, and 3.1 times, respectively. The photocatalytic degradation rate of methylene blue by BiO[ClBrI(CO3)0.5] was 89.5%, indicating the excellent photocatalytic performance of BiO[ClBrI(CO3)0.5]. The stability of BiO[ClBrI(CO3)0.5] was demonstrated through cyclic experiments and XRD analysis before and after the reaction. The photocatalytic degradation of MO by BiO[ClBrI(CO3)0.5] showed that h+ and 1O2 were the main active oxidizing species and •O2- was the secondary active substance. Overall, our work provides new ideas for the synthesis and degradation of organic pollutants by using two-dimensional anionic high-entropy materials.

Investigation of singlet oxygen and superoxide radical produced from vortex-based hydrodynamic cavitation: Mechanism and its relation to cavitation intensity.

Presently, the hydroxyl radical oxidation mechanism is widely acknowledged for the degradation of organic pollutants based on hydrodynamic cavitation technology. The presence and production mechanism of other potential reactive oxygen species (ROS) in the cavitation systems are still unclear. In this paper, singlet oxygen (1O2) and superoxide radical (·O2-) were selected as the target ROS, and their generation rules and mechanism in vortex-based hydrodynamic cavitation (VBHC) were analyzed. Computational fluid dynamics (CFD) were used to simulate and analyze the intensity characteristics of VBHC, and the relationship between the generation of ROS and cavitation intensity was thoroughly revealed. The results show that the operating conditions of the device have a significant and complicated influence on the generation of 1O2 and ·O2-. When the inlet pressure reaches to 4.5 bar, it is more favorable for the generation of 1O2 and ·O2- comparing with those lower pressure. However, higher temperature (45 °C) and aeration rate (15 (L/min)/L) do not always have positive effect on the 1O2 and ·O2- productions, and their optimal parameters need to be analyzed in combination with the inlet pressure. Through quenching experiments, it is found that 1O2 is completely transformed from ·O2-, and ·O2- comes from the transformation of hydroxyl radicals and dissolved oxygen. Higher cavitation intensity is captured and shown more disperse in the vortex cavitation region, which is consistent with the larger production and stronger diffusion of 1O2 and ·O2-. This paper shed light to the generation mechanism of 1O2 and ·O2- in VBHC reactors and the relationship with cavitation intensity. The conclusion provides new ideas for the research of effective ROS in hydrodynamic cavitation process.

Precisely Engineering Asymmetric Atomic CoN4 by Electron Donating and Extracting for Oxygen Reduction Reaction.

The development of nonpyrolytic catalysts featuring precisely defined active sites represents an effective strategy for investigating the fundamental relationship between the catalytic activity of oxygen reduction reaction (ORR) catalysts and their local coordination environments. In this study, we have synthesized a series of model electrocatalysts with well-defined CoN4 centers and nonplanar symmetric coordination structures. These catalysts were prepared by a sequential process involving the chelation of cobalt salts and 1,10-phenanthroline-based ligands with various substituent groups (phen(X), where X=OH, CH3, H, Br, Cl) onto covalent triazine frameworks (CTFs). By modulating the electron-donating or electron-withdrawing properties of the substituent groups on the phen-based ligands, the electron density surrounding the CoN4 centers was effectively controlled. Our results demonstrated a direct correlation between the catalytic activity of the CoN4 centers and the electron-donating ability of the substituent group on the phenanthroline ligands. Notably, the catalyst denoted as BCTF-Co-phen(OH), featuring the electron-donating OH group, exhibited the highest ORR catalytic activity. This custom-crafted catalyst achieved a remarkable half-wave potential of up to 0.80 V vs. RHE and an impressive turnover frequency (TOF) value of 47.4×10-3 Hz at 0.80 V vs. RHE in an alkaline environment.

Pre-Segmented Down-Sampling Accelerates Graph Neural Network-Based 3D Object Detection in Autonomous Driving.

Graph neural networks (GNNs) have been proven to be an ideal approach to deal with irregular point clouds, but involve massive computations for searching neighboring points in the graph, which limits their application in large-scale LiDAR point cloud processing. Down-sampling is a straightforward and indispensable step in current GNN-based 3D detectors to reduce the computational burden of the model, but the commonly used down-sampling methods cannot distinguish the categories of the LiDAR points, which leads to an inability to effectively improve the computational efficiency of the GNN models without affecting their detection accuracy. In this paper, we propose (1) a LiDAR point cloud pre-segmented down-sampling (PSD) method that can selectively reduce background points while preserving the foreground object points during the process, greatly improving the computational efficiency of the model without affecting its 3D detection accuracy. (2) A lightweight GNN-based 3D detector that can extract point features and detect objects from the raw down-sampled LiDAR point cloud directly without any pre-transformation. We test the proposed model on the KITTI 3D Object Detection Benchmark, and the results demonstrate its effectiveness and efficiency for autonomous driving 3D object detection.

Vision-Based On-Road Nighttime Vehicle Detection and Tracking Using Improved HOG Features.

The lack of discernible vehicle contour features in low-light conditions poses a formidable challenge for nighttime vehicle detection under hardware cost constraints. Addressing this issue, an enhanced histogram of oriented gradients (HOGs) approach is introduced to extract relevant vehicle features. Initially, vehicle lights are extracted using a combination of background illumination removal and a saliency model. Subsequently, these lights are integrated with a template-based approach to delineate regions containing potential vehicles. In the next step, the fusion of superpixel and HOG (S-HOG) features within these regions is performed, and the support vector machine (SVM) is employed for classification. A non-maximum suppression (NMS) method is applied to eliminate overlapping areas, incorporating the fusion of vertical histograms of symmetrical features of oriented gradients (V-HOGs). Finally, the Kalman filter is utilized for tracking candidate vehicles over time. Experimental results demonstrate a significant improvement in the accuracy of vehicle recognition in nighttime scenarios with the proposed method.

Reduction of Superoxide Radical Intermediate by Polydopamine for Efficient Hydrogen Peroxide Photosynthesis.

The synthesis of hydrogen peroxide through artificial photosynthesis is a green and promising technology with advantages in sustainability, economy and safety. However, superoxide radical (⋅O2 -), an important intermediate in photocatalytic oxygen reduction to H2O2 production, has strong oxidizing properties that potentially destabilize the catalyst. Therefore, avoiding the accumulation of ⋅O2 - for its rapid conversion to H2O2 is of paramount significance in improving catalyst stability and H2O2 yield. In this work, a strategy was developed to utilize protonated groups for the rapid depletion of converted ⋅O2 -, thereby the efficiency of photocatalytic synthesis of H2O2 from CN was successfully enhanced by 47-fold. The experimental findings demonstrated that polydopamine not only improved carrier separation efficiency, and more importantly, provided the adsorption reduction active site for ⋅O2 - for efficient H2O2 production. This work offers a versatile approach for synthesizing efficient and stable photocatalysts.

Spatial Confinement of Pt Nanoparticles in Carbon Nanotubes for Efficient and Selective H2 Evolution from Methanol.

H2 generation from methanol-water mixtures often requires high pressure and high temperature (200-300 °C). However, CO can be easily generated and poison the catalytic system under such high temperature. Therefore, it is highly desirable to develop the efficient catalytic systems for H2 production from methanol at room temperature, even at sub-zero temperatures. Herein, carbon nanotube-supported Pt nanocomposites are designed and synthesized as high-performance nano-catalysts, via stabilization of Pt nanoparticles onto carbon nanotube (CNT), for H2 production upon methanol dehydrogenation at sub-zero temperatures. Therein, the optimal Pt/CNT nanocomposite presents the superior catalytic performance in H2 production upon methanol dehydrogenation at the expense of B2(OH)4, with the TOF of 299.51 min-130 oC. Compared with other common carriers, Pt/CNT exhibited the highest catalytic performance in H2 production, emphasizing the critical role of CNT in methanol dehydrogenation. The confinement of Pt nanoparticles by CNTs is conducive to inhibiting the aggregation of Pt nanoparticles, thereby significantly increasing its catalytic performance and stability. The kinetic study, detailed mechanistic insights, and density functional theory (DFT) calculation confirm that the breaking of O─H bond of CH3OH is the rate-controlling step for methanol dehydrogenation, and both H atoms of H2 are supplied by methanol. Interestingly, H2 is also successfully produced from methanol dehydrogenation at -10 °C, which absolutely solves the freezing problem in the H2 evolution upon water-splitting reaction.

Boosted Photocatalytic Degradation of Atrazine Using Oxygen-Modified g-C3N4: Investigation of the Reactive Oxygen Species Interconversion.

Elaborating the specific reactive oxygen species (ROS) involved in the photocatalytic degradation of atrazine (ATZ) is of great significance for elucidating the underlying mechanism. This study provided conclusive evidence that hydroxyl radicals (·OH) were the primary ROS responsible for the efficient photocatalytic degradation of ATZ, thereby questioning the reliability of widely adopted radical quenching techniques in discerning authentic ROS species. As an illustration, oxygen-modified g-C3N4 (OCN) was prepared to counteract the limitations of pristine g-C3N4 (CN). Comparative assessments between CN and OCN revealed a remarkable 10.44-fold improvement in the photocatalytic degradation of ATZ by OCN. This enhancement was ascribed to the increased content of C-O functional groups on the surface of the OCN, which facilitated the conversion of superoxide radicals (·O2-) into hydrogen peroxide (H2O2), subsequently leading to the generation of ·OH. The increased production of ·OH contributed to the efficient dealkylation, dechlorination, and hydroxylation of ATZ. Furthermore, toxicity assessments revealed a significant reduction in ATZ toxicity following its photocatalytic degradation by OCN. This study sheds light on the intricate interconversion of ROS and offers valuable mechanistic insights into the photocatalytic degradation of ATZ.

Using waste to treat waste: facile synthesis of hollow carbon nanospheres from lignin for water decontamination.

Lignin, the most abundant natural material, is considered as a low-value commercial biomass waste from paper mills and wineries. In an effort to turn biomass waste into a highly valuable material, herein, a new-type of hollow carbon nanospheres (HCNs) is designed and synthesized by pyrolysis of biomass dealkali lignin, as an efficient nanocatalyst for the elimination of antibiotics in complex water matrices. Detailed characterization shows that HCNs possess a hollow nanosphere structure, with abundant graphitic C/N and surface N and O-containing functional groups favorable for peroxydisulfate (PDS) activation. Among them, HCN-500 provides the maximum degradation rate (95.0%) and mineralization efficiency (74.4%) surpassing those of most metal-based advanced oxidation processes (AOPs) in the elimination of oxytetracycline (OTC). Density functional theory (DFT) calculations and high-resolution mass spectroscopy (HR-MS) were employed to reveal the possible degradation pathway of OTC elimination. In addition, the HCN-500/PDS system is also successfully applied to real antibiotics removal in complex water matrices (e.g. river water and tap water), with excellent catalytic performances.

The effect of polyvinyl chloride (PVC) color on biofilm development and biofilm-heavy metal chemodynamics in the aquatic environment.

Plastic surfaces are colonized by microorganisms and biofilms are formed in the natural aquatic environment. As the biofilm develops, it changes the density and buoyancy of the plastic-biofilm complex, results in plastic sinking, and increases the heavy metals accumulated by biofilm's mobility and availability in aquatic ecosystems. In this experiment, biofilms were cultured on five colors of polyvinyl chloride (PVC; transparent, green, blue, red, black) in an aquatic environment to investigate the effects of plastic color on biofilm formation and development (Phase 1) and to study the effects of being sunk below the photic zone on biofilm (Phase 2). The PVC color significantly affected the biofilm formation rate but had no impact on the final biofilm biomass. After sinking the biofilm-PVC below the photic zone in Phase 2, the layer of diatoms on the biofilm surface began to disintegrate, and the biomass and Chlorophyll-a (Chla) content of the biofilm decreased, except on the red PVC. Below the photic zone, the microbial community of the biofilm changed from primarily autotrophic microbes to mostly heterotrophic microbes. Microbial diversity increased and extracellular polymeric substances (EPS) content decreased. The primary factor leading to microbial diversity and community structure changes was water depth rather than PVC color. The changes induced in the biofilm led to an increase in the concentration of all heavy metals in the biofilm, related to the increase in microbial diversity. This study provides new insights into the biofilm formation process and the effects on a biofilm when it sinks below the photic zone.

Enhancement of electrokinetic-phytoremediation by Ophiopogon japonicus: stimulation of electrokinetic on root system and improvement of polycyclic aromatic hydrocarbon degradation.

Root systems are sensitive to voltage and tend to improve the degradation of organic pollutants by promoting the root exudates and increasing microbial enzyme activity in the rhizosphere under the effect of electrokinetic. In this study, electrokinetic-assisted phytoremediation (EKPR) was applied for the remediation of soil containing phenanthrene (PHE) and pyrene (PYR). Direct current (DC) voltage (1 V cm-1) was applied across the soils for 30 days following 3 treatment schedules (0 h, 4 h, and 12 h per day), referred to as treatments EK0, EK4, and EK12. Electrokinetic assistance improved phytoremediation. Compared to EK0, the removal of PHE and PYR increased by 51.79% and 45.07% for EK4 and by 43.18% and 38.75% for EK12. The applied voltage promoted root growth, stimulated the root exudate release, and increased accumulation of PHE and PYR by plants, and the effect was most pronounced in treatment EK4. Catalase and urease activities in rhizosphere soil also increased, by respective increments of 44.51% and 40.86% for EK4 and by 28.53% and 21.24% for EK12. In this study, we demonstrated that a low voltage applied for an appropriate duration (4 h per day) improves removal of PAHs by stimulating root growth, promoting the root exudate release and enhancing enzyme activity in the microbiome of rhizosphere soil.

Swimming ability of cyprinid species (subfamily schizothoracinae) at high altitude.

The primary objective of this investigation was to study the effect of altitude on fish swimming ability. Different species were tested to ensure that the differences observed are not associated with a single species. Fish critical swimming speed and burst speed were determined using stepped-velocity tests in a Brett-type swimming respirometer. Based on the effects of water temperature and dissolved oxygen, it is clear that the swimming ability of fish decreases as altitude increases. Further, because the effects of high altitude on fish physiology go beyond the effects of lower temperature and dissolved oxygen, we recommend that fish swimming ability be tested at an altitude similar to the target fishway site to ensure the validity of fish data used for fishway design.

Rational design of electrocatalytic system to selective transform nitrate to nitrogen.

Nitrate (NO3-) is one of the most common pollutants in natural bodies of water and as such threatens both human health and the safety of aquatic environment. There are efficient electrochemical techniques to directly remove NO3-, but inexpensive, selective and electrocatalytic strategies to eliminate NO3- by converting it into benign nitrogen (N2) remain challenging. This work studied Cu particles that were formed directly on a Ni foam (Cu-NF) and evaluated their electrocatalytic NO3- reduction performance. The use of carbon nanotubes (CNT) functionalized with titanium suboxides (TiSO) as the anode facilitated the generation of active chlorine species that had a key role in the removal of NH4+. An electrochemical system that integrated a Cu-NF cathode with a TiSO-CNT anode could remove 88.5% of NO3- with a >99% N2 selectivity when operated over 6 h (4.1 × 10-4 h-1) at a potential of -1.2 V vs Ag/AgCl. Because the chloride ions are very common in natural sources of water, this technique offers a sustainable and environmentally friendly approach for the removal of NO3- from contaminated water sources.

Copper Nanowire Networks: An Effective Electrochemical Peroxymonosulfate Activator toward Nitrogenous Pollutant Abatement.

Herein, we developed an electrochemical filtration system for effective and selective abatement of nitrogenous organic pollutants via peroxymonosulfate (PMS) activation. Highly conductive and porous copper nanowire (CuNW) networks were constructed to serve simultaneously as catalyst, electrode, and filtration media. In one demonstration of the CuNW network's capability, a single pass through a CuNW filter (τ < 2 s) degraded 94.8% of sulfamethoxazole (SMX) at an applied potential of -0.4 V vs SHE. The exposed {111} crystal plane of CuNW triggered atomic hydrogen (H*) generation on sites, which contributed to effective PMS reduction. Meanwhile, with the involvement of SMX, a Cu-N bond was formed by the interactions between the -NH2 group of SMX and the Cu sites of CuNW, accompanied by the redox cycling of Cu2+/Cu+, which was facilitated by the applied potential. The different charges of the active Cu sites made it easier to withdraw electrons and promote PMS oxidation. Theoretical calculations and experimental results were combined to suggest a mechanism for pollution abatement with CuNW networks. The results showed that system efficacy for the degradation of a wide array of nitrogenous pollutants was robust across a broad range of solution pH and complex aqueous matrices. The flow-through operation of the CuNW filter outperformed conventional batch electrochemistry due to convection-enhanced mass transport. This study provides a new strategy for environmental remediation by integrating state-of-the-art material science, advanced oxidation processes, and microfiltration technology.

Fast vehicle detection based on colored point cloud with bird's eye view representation.

RGB cameras and LiDAR are crucial sensors for autonomous vehicles that provide complementary information for accurate detection. Recent early-level fusion-based approaches, flourishing LiDAR data with camera features, may not accomplish promising performance ascribable to the immense difference between two modalities. This paper presents a simple and effective vehicle detection method based on an early-fusion strategy, unified 2D BEV grids, and feature fusion. The proposed method first eliminates many null point clouds through cor-calibration. It augments point cloud data by color information to generate 7D colored point cloud, and unifies augmented data into 2D BEV grids. The colored BEV maps can then be fed to any 2D convolution network. A peculiar Feature Fusion (2F) detection module is utilized to extract multiple scale features from BEV images. Experiments on the KITTI public benchmark and Nuscenes dataset show that fusing RGB image with point cloud rather than raw point cloud can lead to better detection accuracy. Besides, the inference time of the proposed method reaches 0.05 s/frame thanks to its simple and compact architecture.

In Vivo NIR-II Fluorescence Lifetime Imaging of Whole-Body Vascular Using High Quantum Yield Lanthanide-Doped Nanoparticles.

Second near infrared (NIR-II, 1000-1700 nm) fluorescence lifetime imaging is a powerful tool for biosensing, anti-counterfeiting, and multiplex imaging. However, the low photoluminescence quantum yield (PLQY) of fluorescence probes in NIR-II region limits its data collecting efficiency and accuracy, especially in multiplex molecular imaging in vivo. To solve this problem, lanthanide-doped nanoparticles (NPs) ß-NaErF4 : 2%Ce@NaYbF4 @NaYF4 with high PLQY and tunable PL lifetime through multi-ion doping and core-shell structural design, are presented. The obtained internal PLQY can reach up to 50.1% in cyclohexane and 9.2% in water under excitation at 980 nm. Inspired by the above results, a fast NIR-II fluorescence lifetime imaging of whole-body vascular in mice is successfully performed by using the homebuilt fluorescence lifetime imaging system, which reveals a murine abdominal capillary network with low background. A further demonstration of fluorescence lifetime multiplex imaging is carried out in molecular imaging of atherosclerosis cells and different organs in vivo through NPs conjugating with specific peptides and different injection modalities, respectively. These results demonstrate that the high PLQY NPs combined with the homebuilt fluorescence lifetime imaging system can realize a fast and high signal-to-noise fluorescence lifetime imaging; thus, opening a road for multiplex molecular imaging of atherosclerosis.

Electrocatalytic transformation of oxygen to hydroxyl radicals via three-electron pathway using nitrogen-doped carbon nanotube-encapsulated nickel nanocatalysts for effective organic decontamination.

The selective electrochemical reduction of oxygen (O2) via 3e- pathway for the production of hydroxyl radicals (HO) is a promising alternative to conventional electro-Fenton process. Here, we developed a nitrogen-doped CNT-encapsulated Ni nanoparticle electrocatalyst (Ni@N-CNT) with high O2 reduction selectivity for the generation of HO•via 3e- pathway. Exposed graphitized N on the CNT shell, and Ni nanoparticles encapsulated within the tip of the N-CNT, played a key role in the generation of H2O2 intermediate (*HOOH) via a 2e- oxygen reduction reaction. Meanwhile, those encapsulated Ni nanoparticles at the tip of the N-CNT facilitated the sequential HO• generation by directly decomposing the electrogenerated *H2O2 in a 1e- reduction reaction on the N-CNT shell without inducing Fenton reaction. Improved bisphenol A (BPA) degradation efficiency were observed when compared with conventional batch system (97.5% vs 66.4%). Trials using Ni@N-CNT in a flow-through configuration demonstrated a complete removal of BPA within 30 min (k = 0.12 min-1) with a limited energy consumption of 0.068 kW·h·g-1 TOC.

Solar-to-H2 O2 Energy Conversion by the Photothermal Effect of a Polymeric Photocatalyst via a Two-Channel Pathway.

With a view to using solar energy, the exploitation of near-infrared (NIR) light, which constitutes about 50 % of solar energy, in photocatalytic H2 O2 synthesis remains challenging. In this study, resorcinol-formaldehyde (RF), which has a relatively low bandgap and high conductivity, is introduced for photothermal catalytic generation of H2 O2 under ambient conditions. Owing to the promoted surface charge transfer rate under high temperature, the photosynthetic yield reaches roughly 2000 µm within 40 min under 400 mW cm-2 irradiation with a solar-to-chemical conversion (SCC) efficiency of up to 0.19 % at 338 K under ambient conditions, exceeding the rate of photocatalysis with a cooling system by a factor of about 2.5. Notably, the H2 O2 produced by RF during photothermal process was formed via a two-channel pathway, leading to the overall promotion of H2 O2 formation. The resultant H2 O2 can be applied in situ for pollutant removal. This work offers a sustainable and economical route for the efficient formation of H2 O2 .

EBV-Upregulated B7-H3 Inhibits NK cell-Mediated Antitumor Function and Contributes to Nasopharyngeal Carcinoma Progression.

Nasopharyngeal carcinoma (NPC) is an Epstein-Barr virus (EBV)-associated epithelial malignancy characterized by the presence of prominent infiltration of lymphocytes, including natural killer (NK) cells. Although NK cells can directly target EBV-infected tumor cells without restriction by the MHC, EBV-positive (EBV+) NPC cells often develop resistance mechanisms that allow them to evade immune surveillance by NK cells. Elucidating the mechanisms involved in EBV-induced NK-cell dysfunction will contribute to the design of novel NK cell-based immunotherapies to treat NPC. Herein, we confirmed that the cytotoxic function of NK cells was impaired in EBV+ NPC tissues and found that EBV infection-induced expression of B7-H3 in NPC negatively correlated with NK-cell function. The inhibitory effect of EBV+ tumor expression of B7-H3 on NK-cell function was clarified in vitro and in vivo. Mechanistically, activation of the PI3K/AKT/mTOR signaling pathway via EBV latent membrane protein 1 (LMP1) was responsible for EBV infection-induced upregulation of B7-H3 expression. In an NPC xenograft mouse model with adoptive transfer of primary NK cells, deletion of B7-H3 on tumor cells in combination with anti-PD-L1 treatment restored NK cell-mediated antitumor activity and significantly improved the antitumor efficacy of NK cells. On the basis of our findings, we conclude that EBV infection can inhibit NK cell-mediated antitumor function by inducing upregulation of B7-H3 expression and provide a rationale for NK cell-based immunotherapies in combination of PD-L1 blockade and overcoming the immunosuppression of B7-H3 to treat EBV-associated NPC.

Combined effects of fluoroquinolone antibiotics and organophosphate flame retardants on Microcystis aeruginosa.

As freshwater harmful algal blooms continue to rise in frequency and severity, increasing focus is made on the effects of mixed pollutants and the dominant cyanobacterial species Microcystis aeruginosa (M. aeruginosa). However, few studies have investigated whether M. aeruginosa has a synergistic relationship with two common pollutants, namely, organophosphate flame retardants (OPFRs) and fluoroquinolone antibiotics (FQs). In this paper, three FQs and three OPFRs commonly detected in freshwaters were selected to construct a ternary mixture of FQs, a ternary mixture of OPFRs, and a six-component mixture of OPFRs and FQs. The effects of single substance and mixture on the growth of M. aeruginosa were determined at 24, 48, 72, and 96 h, and the toxicities of the mixture were evaluated by concentration addition model and independent action model. The results showed that the mixture of FQs and the mixture of OPFRs do not show toxicological interaction. However, partial mixtures of OPFRs and FQs showed antagonism or synergism at different concentrations and times. This indicated that combined toxicities of OPFRs and FQs on M. aeruginosa were mixture ratio dependent, concentration dependent and time dependent. This study improves our understanding of the role of OPFRs and FQs in cyanobacterial outbreaks of Microcystis.