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Dissolved organic matter (DOM) has been found to attenuate the ecotoxicity of various environmental pollutants, but research on its own toxic effects in aquatic ecosystems has been very limited. Herein, the toxic effects of humic acid (HA), a represent DOM typically found in natural waters, on the freshwater alga Scenedesmus capricornus were investigated. As result, HA exerted a double-dose effect on the growth of Scenedesmus capricornus. At HA concentrations below 2.0 mgC/L, the growth of Scenedesmus capricornus was slightly promoted, as was the synthesis of chlorophyll and macromolecules in the algae. Moreover, S. capricornus can maintain its growth by secreting fulvic acid as a nutrient carbon source. However, the growth of Scenedesmus capricornus was significantly inhibited when HA was beyond 2.0 mgC/L. The main mechanisms of humic acid's toxicity were membrane damage and oxidative stress. Particularly, when the oxidative stress exceeds the algae's carrying capacity, the synthesis of EPS is greatly inhibited and HA damage results. Taken together, DOM may have both positive and negative effects on aquatic ecosystems.

Sediment dredging is an effective means to control the endogenous pollution of lakes, which could significantly change the concentration and composition of organic matter, especially dissolved organic matter (DOM) in the lake. DOM is particularly important for the release of endogenous pollutants, which will inevitably bring an impact on aquatic biodiversity. Nevertheless, in recent research little attention has been paid to the desorption mechanism of DOM on pollutants and the change of biodiversity during dredging. This study investigated the physicochemical properties of DOM in the sediment by taking a sediment dredging project in Dianchi Lake in China for example. The correlations of DOM properties with the desorption behavior of nitrogen (N), phosphorus (P), cadmium (Cd), lead (Pb) and the biodiversity of aquatic organisms were analyzed. The results show that the aromaticity and humification of DOM were improved after dredging, and the high molecular weight DOM was degraded into low molecular weight substance. The desorption amount of N, P and heavy metals (Cd, Pb) were decreased as the pH values increased. Moreover, NH

Antibiotics, antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) are ubiquitous in the reclaimed water, posing a potential threat to human and ecological health. Nowadays, the reuse technology of reclaimed water has been widely concerned, but the removal of antibiotics, ARB and ARGs in reclaimed water has not been sufficiently studied. This study used TiO2 nanotube arrays (TNTs) decorated with Ag/SnO2-Sb nanoparticles (TNTs-Ag/SnO2-Sb) as the anode and Ti-Pd/SnO2-Sb as the cathode to construct an efficient photoelectrocatalytic (PEC) system. In this system, 99.9% of ARB was inactivated in 20 min, meanwhile, ARGs was removed within 30 min, and antibiotics were almost completely degraded within 1 h. Furthermore, the effects of system parameters on the removals of antibiotics, ARB and ARGs were also studied. The redox performance of the system was verified by adding persulfate. Escherichia coli, as a representative microorganism in aquatic environments, was used to evaluate the ecotoxicity of PEC treated chloramphenicol (CAP) solution. The ecotoxicity of CAP solution was significantly reduced after being treated by PEC. In addition, transformation intermediates of CAP were identified using liquid chromatography-tandems mass spectrometry (LC-MS/MS) and the possible degradation pathways were proposed. This study could provide a potential alternative method for controlling antibiotic resistance and protecting the quality of reclaimed water.

Lignocellulosic aerogels were prepared directly from whole biomass Douglas fir wood without prior removal of hemicellulose and lignin using lithium bromide (LiBr) molten salt hydrate (lithium bromi...

We study the dynamics of a delayed diffusive hematopoiesis model with two types of Dirichlet boundary conditions. For the model with a zero Dirichlet boundary condition, we establish global stability of the trivial equilibrium under certain conditions, and use the phase plane method to prove the existence and uniqueness of a positive spatially heterogeneous steady state. We further obtain delay-independent as well as delay-dependent conditions for the local stability of this steady state. For the model with a non-zero Dirichlet boundary condition, we show that the only positive steady state is a constant solution. Results for the local stability of the constant solution are also provided. By using the delay as a bifurcation parameter, we show that the model has infinite number of Hopf bifurcation values and the global Hopf branches bifurcated from these values are unbounded, which indicates the global existence of periodic solutions.

Poplar wood was rapidly fractionated via a flow-through reaction using aqueous solutions of an acid hydrotrope (AH), p-toluenesulfonic acid (p-TsOH), at temperatures below 98 °C. 13C–1H two-dimensional nuclear magnetic resonance (NMR) spectroscopic analyses demonstrated that the AH-solubilized lignins (AHLs) from a range of fractionation conditions with yields up to approximately 80% had a very high content of β-aryl-ether linkages compared to milled wood lignin (MWL) with a low enough condensation to facilitate subsequent reductive catalytic depolymerization resulting in a lignin monomer yield of over 30%. Gel-permeation chromatographic (GPC) and differential scanning calorimetric (DSC) analyses showed that the AHLs have high molecular weights and low glass transition temperatures Tg. These AHLs also have a pinkish color suitable for applications such as cosmetics and dye dispersants. AH fractionation (AHF) preserved the cellulose fraction as solid fibers also with a light pinkish color for the materials...

All kinds of wastewaters containing steroid estrogens (SEs) and mixed endogenous source dissolved organic matter (DOM) enter natural water environments with intermittent illumination where microbial action occurs in a relatively deep natural aqueous environment. The role of mixed endogenous source DOM in SEs’ biodegradation and photochemical degradation in such environments was studied using 17β-estradiol (E2) in laboratory experiments under anaerobic conditions. The experimental results show that microbial action can improve the optical properties and electron transfer capability of mixed endogenous source DOM, promoting photodegradation and biodegradation. Intermittent illumination attenuates DOM’s electron transfer capacity and its chromophore groups, but it improves the bioavailability of low molecular weight dissolved organic matter which promotes microbial growth under anaerobic conditions. DOM-mediated co-degradation by light and microbial action over three days was better than either individually. The presence of Fe(III) promoted electron transfer, and Fe(III)-DOM complexes accelerated energy transfer under irradiation, enhancing photodegradation. Any remaining estrogens will continue to degrade, most effectively in well-aerated waters with sufficient illumination.

Phenolation is an effective method to improve the reactivity of lignin in the synthesis of lignin–phenol–formaldehyde (LFP) resin. Previous lignin phenolation was almost exclusively catalyzed by ac...

Photolysis and microbial activity are relatively obvious in shallow, eutrophic waters with low dissolved oxygen content. Ubiquitous humic acid (HA) can act as electron acceptor and be reduced by bacterial under such conditions, and the reduced form of humic acid (RHA) plays an important role in the photolysis contaminants. In this study, anaerobic 17α-ethinylestradiol (EE2) photodegradation was performed along with biodegradation by Shewanella putrefaciens mediated by HA. The mechanism of such coupled photolysis and biodegradation of EE2 was thus elucidated. The removal rate in such coupled degradation in the presence of 10 mgC L−1 of HA at pH 8.0 was greater than that of either photolysis or biodegradation alone. HA which had been reduced in a double-chamber microbial fuel cell showed better promotion to EE2 photodegradation than fresh HA. Reactive species scavenging experiments indicated that hydroxyl radical and excited triplet states of HA were primary contributors to EE2 photodegradation in anaerobic conditions. More of them were produced from RHA than from pristine HA. Besides, the degraded EE2 solutions inhibited the proliferation of MCF-7 human cancer Cells. These findings improve our understanding of the environmental transformation of EE2 in the shallow, anoxic waters.

The lignin from AFEX-pretreated corn stover and lignin model compounds were evaluated as the sole carbon source for microbial lipid production by Rhodococcus opacus NRRL B-3311. R. opacus NRRL B-3311 could grow on the AFEX-lignin without pretreatment and accumulate lipids up to 32 mg/L in 72 h with consuming 20% of the total lignin. The lipid produced from lignin had a similar fatty acid compositional profile to those of vegetable oil. Based on the metabolism analysis, R. opacus NRRL B-3311 could depolymerize AFEX-lignin and catabolize the aromatic compounds derived from the lignin. Study using aromatic model compounds found that R. opacus NRRL B-3311 preferably utilized 4-hydroxybenzoic acid as the sole carbon source over glucose, while it could not grow on p-coumaric acid or vanillin.

Dissolved organic matter plays a significant role in determining chemical oxygen demand. Resin fractionation is the most widely used technique which isolates fractions based on their hydrophobicity and hydrophilicity. In this study, DAX-8 and XAD-4 resins were used to investigate the relationship between hydrophobic and hydrophilic organic matters and their contributions to chemical oxygen demand in three Chinese lakes and in treated sewage. In Chenghai Lake, the average chemical oxygen demand attributable to hydrophobic organic matter was 10.20 mg/L and that from hydrophilic organic matter was 3.08 mg/L. As a proportion of the total chemical oxygen demand, they were 27 and 8%, respectively. In Yangzonghai Lake, the hydrophilic organic matter contributed 42% of the total chemical oxygen demand, while the hydrophobic organic matter contributed only about 18%. In Dianchi Lake, the hydrophobic and hydrophilic organic matters adsorbed by the resins were comparable. In treated sewage, on average, about 21% of the TCOD was from hydrophobic organic matter and 13% was from hydrophilic organic matter. The ratios of hydrophobic and hydrophilic organic matters to total chemical oxygen demand in the three lakes and in the treated sewage were different, indicating the differences among the three typical major plateau lakes in chemical oxygen demand contribution origin and in pollution process.

Ascribing to their significant differences in physicochemical properties, it is extremely challenging to treat complex wastewater containing more than one class of pollutants via one-step treatment. Here, we focused on disposal of complex wastewater bearing organic dye and heavy metal by using adsorptive method. Thus, by combining the advantages of polyethyleneimine (PEI), β-cyclodextrin (β-CD) as well as Fe3O4 magnetic nanoparticles, a versatile β-CD and PEI bi-functionalized magnetic nanoadsorbent (Fe3O4-PEI/β-CD) with spatially separated sorption sites was successfully constructed for simultaneous capture of methyl orange (MO) and Pb(II) in complex wastewater. In this setting, β-CD cavities and positively charged N-containing groups of PEI were mainly responsible for removal of MO via host-guest inclusion and electrostatic attraction, respectively, and oxygen-bearing groups on the edge of β-CD as well as the free amino moieties in PEI acted as the active sites for Pb(II) uptake. In their individual mono-pollutant system, the adsorption processes can be better described via applying pseudo-second-order kinetic and Langmuir isotherm models. Interestingly, presence of MO in Pb(II)-MO binary system significantly promoted the uptake of Pb(II). But the coexisting Pb(II) had almost no effects on MO uptake. Such results demonstrated that both MO and Pb(II) could be simultaneously and synergistically removed by Fe3O4-PEI/β-CD through multiple mechanisms (such as electrostatic attraction, host-guest inclusion, chelating, etc.). Particularly, the excellent regeneration and stability make Fe3O4-PEI/β-CD an ideal integrative adsorbent for purification of actual wastewater contaminated by MO and Pb(II). Thus, this study provides some insights into designing a well-performed and easily recyclable adsorbent for simultaneous and synergetic capture of both organic and inorganic contaminants in complex wastewater.

The treatment of a real pharmaceutical production wastewater by electrolysis using three-dimensional electrodes (3D electrolysis), ozonation, and their combined process (3D/O3) was investigated in this study. The pharmaceutical wastewater was characterized by a high organic concentration (total organic carbon (TOC) of 13,475 mg/L) and high acute toxicity (100% inhibition of the luminescent bacterial Vibrio fischeri). After 6 h treatment, ∼23% and 43% of TOC could be removed from the pharmaceutical wastewater by individual ozonation and the 3D electrolysis process using granular activated carbon (GAC) as the particle electrodes, respectively. However, the acute toxicity of the wastewater was hardly reduced by the two individual processes. In comparison, by sparging the ozone generator effluent (oxygen and ozone gas mixture) in the three-dimensional electrode reactor, the 3D/O3 process considerably enhanced TOC abatement to ∼71% and reduced the inhibition of the luminescent bacterial to OH) production in the 3D/O3 process via several reaction mechanisms, e.g., the reaction of sparged O3 with in situ generated H2O2, the electrochemical reduction of O3, and GAC catalyzed O3 decomposition, which in turn enhanced the oxidation of organics in the bulk and those adsorbed onto the GAC particle electrodes. The results of this study indicate that there exists a synergistic effect between 3D electrochemical process and ozonation for the degradation of toxic organics in the pharmaceutical wastewater. Compared with the two individual processes, the 3D/O3 process can thus provide a more effective option for the treatment of high-strength pharmaceutical wastewater.

Ascribing to their significant differences in physicochemical properties, it is extremely challenging to treat complex wastewater containing more than one class of pollutants via one-step treatment. Here, we focused on disposal of complex wastewater bearing organic dye and heavy metal by using adsorptive method. Thus, we successfully fabricated a novel and versatile EDTA functionalized magnetic chitosan composite adsorbent (Fe3O4-CS/EDTA) for simultaneous removal of methyl blue(MB) and heavy metal (Pb(II) and Cu(II)) from complex wastewater. In this setting, EDTA chelating groups are mainly responsible for the binding of heavy metals, while the protonated amino groups of CS adsorb anionic dyes through electrostatic interaction, thus enabling the simultaneous capture of these two classes of pollutants. In mono-pollutant system, the resulting material showed prominent uptake ability toward MB, Pb(II), and Cu(II) with uptake characteristics of pseudo-second-order model and Langmuir isotherm equation. The maximum monolayer uptake capacities were determined to be 225.0 mg g−1 of Cu(II), 220.0 mg g−1 of Pb(II), and 459.9 mg g−1 of MB at 303 K, respectively. More interestingly, in metal-MB binary system, uptake of MB was almost not affected by coexisting metal. While the uptake capacity of Cu(II) or Pb(II) was enhanced with increasing of MB concentration. These results demonstrated the synergetic removal performance of as-designed adsorbent toward cationic metal ions and anionic dye. Moreover, as-resulting adsorbent showed no significant adsorption capacity loss even after 8 runs of sorption-desorption cycle, manifesting that it is of great stability and could be regarded as a promising candidate adsorbent for treating complex wastewater. This study provides some insights into the design of highly efficient adsorbents with spatially separated sorption sites for disposing complex wastewater bearing organic and metallic contaminants.

The adsorption behavior of Cu(II) and Cd(II) onto a magnetic lignin-based nanomaterial (MLN) was investigated in detail. The results showed that the adsorption isotherm was better described by the Langmuir model, showing monolayer adsorption with a maximum adsorption capacity of 135.7 and 156.5 mg/g. The kinetics fit the pseudo-second-order model. The thermodynamics showed the enthalpy change of the adsorption for Cu(II) and Cd(II) was 24.12 and 36.49 kJ/mol, with entropy change of 85.12 and 130.3 J/mol·K, respectively; thus, the adsorption was endothermic and spontaneous in the range of 25°C–45°C. Additionally, the adsorbent was easy to regenerate. This study shows that MLN is a capable, sustainable absorbent for the removal of heavy metals.

This study demonstrated a high-yield process to synthesize glucooligosaccharides (GlOS) from glucose via non-enzymatic glycosylation in an acidic lithium bromide trihydrate (ALBTH, a concentrated aqueous solution of LiBr containing a small amount of acid) system. The single-pass yield of the GlOS was up to 75%, which was the highest yield ever reported. The synthesized GlOS consisted of 2–9 glucose units linked predominantly via α/β–1,6 glycosidic bonds (69%), followed by α/β–1,3, α/β–1,2, α/β–1,1, and α–1,4 glycosidic bonds. Preliminary in vitro fermentation tests indicated that GlOS could be utilized by select gut probiotic strains, suggesting that GlOS had the potential as prebiotics. The enhanced glucose glycosylation in ALBTH was attributed to the unique properties of the solvent system, including water-deficient nature, extra-high capacity of dissolving glucose, and enhanced acid catalysis. The LiBr salt could be recovered after separating the GlOS by anti-solvent precipitation and directly reused. This process provided a new approach for valorizing the biomass derived glucose into high-value oligosaccharides.

Breast cancer is the most diagnosed diseases and the second-leading cause of death in females, among which the estrogen receptor positive (ER+) patients are more common of all cases. In present study, we selected MCF-7 as an in vitro model and investigated the combinatorial anti-proliferative effects of tamoxifen and naringenin on ER+ breast cancer, and then explored the potential mechanisms involved in mitochondrial dysfunction and oxidative stress mediated by several estrogen receptor subtypes. Six assessment endpoints including cell viability, cell migration, cell cycle, cell apoptosis, mRNA, and protein expression were estimated. Tamoxifen and naringenin were shown to inhibit the cell growth of MCF-7 cells at higher concentrations, and co-exposure with them significantly inhibited cell proliferation in an additive manner. Results from a wound healing assay indicated that the combined treatment of tamoxifen and naringenin markedly suppressed cell migration compared with the single exposure by downregulating the expression of MMP-9 and MMP-2. Flow cytometry analysis revealed that the combined treatment of tamoxifen and naringenin blocked cell cycle in G2/M phase through suppressing the transcription of cell cycle regulation proteins. Simultaneously, co-treatment with them also induced cell apoptosis by regulating the expression of mitochondrial apoptotic proteins as well as by simulating the production of reactive oxygen species (ROS). Real-time quantitative polymerase chain reaction (RT-qPCR) and western blotting (WB) analysis results further demonstrated that the two nuclear estrogen receptors-ERα66 and ERβ, as well as the two membrane estrogen receptors-ERα36 and GPR30 were downregulated when cells were exposed to single tamoxifen, whereas naringenin treatment group not only downregulated the expression of ERα66 and GPR30 but also upregulated ERβ and ERα36. Interestingly, co-treatment group resulted in significant downregulation of ERα66, ERα36 and GPR30 but upregulation of ERβ. Taken together, co-treatment of tamoxifen and naringenin could inhibit cell proliferation more effectively in ER+ breast cancer cells, which was associated with a modulation of the expression levels of several estrogen receptors.

The present study demonstrated a novel method to fabricate composite aerogels from the two most abundant, natural, and renewable materials on earth (cellulose and chitosan) as a self-indicating biosorbent to remove formaldehyde from indoor air. The aerogel was prepared via a process of co-dissolution and regeneration of cellulose and chitosan in an inorganic ionic liquid (a concentrated aqueous solution of lithium bromide), in which cellulose contributes to the porous structure and the physical strength of the aerogel, and chitosan provides the reactive sites (amino groups) to chemically bind formaldehyde. The cellulose–chitosan composite aerogel had a highly porous structure and a large surface area (245 m2 g−1), which are favorable properties for a sorbent. The results indicated that a composite aerogel (chitosan to cellulose mass ratio 1 : 2) could quickly and irreversibly adsorb formaldehyde with an observed adsorption capacity of up to 7.5 mmol g−1 (224 mg g−1) when exposed to excessive formaldehyde. The high adsorption capacity of the composite aerogel was primarily attributed to the chemical adsorption via the instantaneous chemical reaction between the amino groups of chitosan and formaldehyde. The physical adsorption of formaldehyde on the aerogel had an insignificant contribution to the overall adsorption capacity. The incorporation of ninhydrin into the composite aerogel provided a real-time color change mechanism to indicate the saturation or expiration of the cellulose–chitosan biosorbent for remediating formaldehyde from indoor air.

This study demonstrated a facile method to synthesize lignin-based carbon dots (L-CDs) first. Results indicated that the L-CDs had a diameter of 2–5 nm and a graphene-like crystalline structure. It was found that under the optimal synthesis conditions, the fluorescence lifetime of L-CDs was about 12 ns. Within the range of pH 1–10, the fluorescence intensity of the L-CDs and pH value followed a linear relationship. With the contribution of L-CDs, pH/temperature dual responsive hydrogel was synthesized. The elastic modulus G′ of hydrogel was much higher than viscous modulus G″. When the PVA content was larger than 10 wt%, the temperature sensitivity and water retention rate gradually decreased. The skeleton of hydrogels had a typical porous honeycomb structure, which made it possible to control its internal pore size by adjusting the content of PVA. There was a linear relationship between the fluorescence intensity of hydrogels and pH value in the range of pH 1–7. Therefore, the pH/temperature dual responsive hydrogel presented a new route for designing tissue engineering scaffolds and drug carriers.

The cathode current commutation of IGCT relies on the energy stored in the turn-off capacitor stack to realize current transfer. Due to the loop parasitic resistance, the forward voltage of the turn-off circuit must higher than the reverse voltage generated by parasitic resistance during commutation. Therefore, the capacitance and voltage of the turn-off capacitor need to meet the turn-off demand at the maximum turn-off current, and meet the time constant of frequency charge and discharge at the same time. The turn-off capacitor stack is generally tens of mF. When the gate pole and cathode pole short together, the energy in the turn-off capacitor stack will discharge through the turn-off MOSFET stack, this process can cause failure of the turn-off MOSFET stack. This paper studies on the characteristics of the turn-off circuit, and compares the current characteristics of the MOSFET stack under regular turn-off and GK short, and proposes a short-circuit protection method to ensure that the gate unit can shutdown the turn-off circuit immediately when GK short and ensure the dynamic and static turn-off characteristics successfully.

This paper presents a novel 6-inch 4.5SkV reverse blocking-integrated gate commutated thyristor(RB-IGCT), which has a current turn-off capability of 500A and reverse voltage blocking capability of 4.5kV. And it is expected to be used in DC converter valves to help the grid system to solve the problem of commutation failure actively. According to the application of the power grid, a special gate unit for drive (GUD) was designed for RB-IGCT, and new technologies such as black start, low power consumption, signal encoding, and logic control were developed. Finally, a 10kV RB-IGCT module was designed, and a test platform was built to study the turn-off characteristics and reverse recovery characteristics of the RB-IGCT, then the turn-off characteristics of the module is analyzed. The research and development of RB-IGCT are of great significance, and it is expected to be widely used in future power grids.

With the global spread of the COVID-19 pandemic, the water pollution caused by extensive production and application of COVID-19 related drugs has aroused growing attention. Herein, a novel biochar-supported red mud catalyst (RM-BC) containing abundant free hydroxyl groups was synthesized. The RM-BC activated persulfate process was firstly put forward to degrade COVID-19 related drugs, including arbidol (ARB), chloroquine phosphate, hydroxychloroquine sulfate, and acyclovir. Highly effective removal of these pharmaceuticals was achieved and even 100% of ARB was removed within 12 min at optimum conditions. Mechanism study indicated that SO

17 alpha-ethinylestradiol (EE2) in natural waters can seriously harm ecosystems and human health. Dissolved organic matter (DOM) and iron minerals are ubiquitous in natural waters, and they can shorten the half-life of EE2 in the natural environment. The interaction between dissolved organics and iron affects pollutants' transformation pathways. The mechanism of EE2's adsorption on hematite, magnetite and pyrite was studied. A photo-Fenton system was constructed in which humic acid (HA) and iron minerals degraded EE2 under simulated natural light conditions. Pyrite showed the best adsorption and degradation in acidic conditions (52%) for 5 h. Hydroxyl radical was found to be the main active substance in the photodegradation. The degradation products of EE2 were identified and possible degradation pathways were inferred. These results can contribute to the understanding of the transformation pathways of persistent organic pollutants in natural waters.

Plastic is a major component of solid waste. It is often thermally treated, generating microplastics and plastic-char which end up as landfill. This study investigated the potential of plastic-char for treating persistent organic pollutants of aqueous media using 17α-ethinylestradiol (EE2) as a target contaminant. The adsorption and photodegradation capacity of plastic-char were investigated, and the adsorption isotherms revealed that EE2 adsorption on char is heterogeneous and multilayered. The presence of Fe was found to greatly enhance EE2 adsorption rate and capacity as well as photochemical degradation ability of plastic-char. Quenching experiments proved that electron transfer between triplet states of plastic-char and Fe(III) and the production of H2O2 were the rate-limited steps in the generation of reactive species. Hydroxyl radical and holes were found to be the predominant reactive species contributing to the EE2 photodegradation. This study not only elucidated the possible environmental behavior of plastic-char discharged as bottom ash in the natural transformation of persistent organic pollutants, but also suggested that water treatment may offer a use for some of the enormous volume of plastic waste now being generated worldwide.

Real-time emotion recognition in conversations (RTERC), the task of using the historical context to identify the emotion of a query utterance in a conversation, is important for opinion mining and building empathetic machines. Existing works mainly focus on obtaining each utterance representation separately and then utilizing utterance-level features to model the emotion representation of the query. These approaches treat each utterance as a unit and capture the utterance-level dependencies in the context, but ignore the word-level dependencies among different utterances. In this paper, we propose a multi-view network (MVN) to explore the emotion representation of a query from two different views, i.e., word- and utterance-level views. For the word-level view, MVN takes the context and query as word sequences and then models the word-level dependencies among utterances. For the utterance-level view, MVN extracts each utterance representation separately and then models the utterance-level dependencies in the context. Experimental results on two public emotion conversation datasets show that the proposed model outperforms the state-of-the-art baselines.

Anammox is a novel and efficient nitrogen removal technique, while the long start-up time limits its industrial application, thus carriers are always utilized to accelerate its start-ups. Meanwhile, the preservation of anammox bacteria is a key element in its application. Therefore, it is also quite significant to evaluate the effect of carriers in reactivation of the anammox process after preservation. Through addition of polyurethane sponge in the upflow anaerobic sludge blanket (UASB) reactor (R1), comparing with the one without polyurethane sponge addition (R2), the time for anammox start-up was shorten by 28%, and the reactivation time was reduced by 50%. The preservation in 4 ℃ did not significantly affect the survival of anammox bacteria, but significantly decreased their nitrogen removal rate (NRR). Moreover, during the preservation, the decomposed EPS in R1 (44%) was less compared to that in R2 (66%). It took 36 days for R1 to recover the NRR (0.084 kg·N·m-3·d-1), but took 60 days for R2. At the end of reactivation, the abundance of Candidatus (Ca.) Brocadia and Ca. Kuenenia (both are anammox bacteria) was 4.5% and 2.7%, respectively, in R1, whereas there was no identified Ca. Kuenenia and the Ca. Brocadia was only 0.2% in R2. Therefore, the addition of polyurethane sponge could short the start-up and reactivation time for anammox process by retaining more anammox bacteria in the reactor.

Humic acids (HA) are common mediators in redox reactions in the aquatic environment. The structures and properties of HA are greatly influenced by environmental factors such as external electrons. In this study, qualitative changes in electron-modified HA and the underlying mechanisms were reported, which not only contribute to understanding the fate of HA and their impact on organic pollutants, but could facilitate their potential use for water purification. The photochemical activity and electron-donating capacity of HA were improved due to the increase of phenolic and carboxyl components via the reduction modification by electrons, creating a novel and efficient photo-bio-electro-Fenton system mediated by HA under neutral conditions without the use of hydrogen peroxide (H2O2). The in-situ continuous production of H2O2 ensured an adequate supply of hydroxyl radicals in this coupled system, achieving mineralization (92%) of HA and 17α-ethinylestradiol (EE2), a common synthetic estrogen with high estrogenic potency. Two degradation pathways with five degradation intermediates of EE2 were identified in our study. Effluents from the coupled system showed decreased endocrine-disrupting activity. Our findings demonstrated a new approach for the in-situ modification and potential use of HA for water treatment and particularly the concurrent degradation of HA and organic pollutants through a photo-bioelectrochemical system mediated by HA.

The large amount of municipal wastewater discharged into urban rivers sometimes exceeds the rivers’ self-purification capacity leading to black-odorous polluted water. Electro-flocculation has emerged as a powerful remediation technology. Electro-flocculation in a bubble column tower with a bipolar electrode (BPE) was tested in an attempt to overcome the high resistance and weak gas-floatation observed with a monopolar electrode (MPE) in treating such water. The BPE reactor tested had a Ti/Ta2O5-IrO2 anode and a graphite cathode with an iron or aluminum bipolar electrode suspended between them. It was tested for its ability to reduce turbidity, phosphate and sulphion and to increase the concentration of dissolved oxygen. The inclusion of the bipolar electrode was found to distinctly improved the system’s conductivity. The system’s electro-flocculation and electrical floatation removed turbidity, phosphate and sulphion completely, and the dissolved oxygen level improved from 0.29 to 6.28 mg/L. An aluminum bipolar electrode performed better than an iron one. Changes in the structure of the microbial community confirmed a significant improvement in water quality.

Microplastic pollution in cultivated soil has received increasing attention recently. There may be more serious microplastic abundance but little research has been done in cultivated soil in plateau areas. To survey the pollution characteristics of microplastics in inland cultivated soil, 100 soil samples collected from 10 counties of Yunnan Province were investigated through density separation and microscopic examination. The research results showed that microplastic abundance was in the range of 0.9 × 103 to 40.8 × 103 particles (kg Ds)−1 with average abundance of 9.8 × 103 particles (kg Ds)−1. Moreover, compared with other studies on sediments, it was found that microplastic abundance in inland soil was one order of magnitude higher than that in offshore sediments. The use of plastic mulch and its long-term residue in cultivated soil was an important reason for microplastic pollution. In this survey, various morphologies of microplastics existed, including fragment (78.3%), transparent/translucency (49.7%), and micro-size microplastics (

Cellulose‐based triboelectric nanogenerators (TENGs) have gained increasing attention. In this study, a novel method is demonstrated to synthesize cellulose‐based aerogels and such aerogels are used to fabricate TENGs that can serve as mechanical energy harvesters and self‐powered sensors. The cellulose II aerogel is fabricated via a dissolution–regeneration process in a green inorganic molten salt hydrate solvent (lithium bromide trihydrate), where. The as‐fabricated cellulose II aerogel exhibits an interconnected open‐pore 3D network structure, higher degree of flexibility, high porosity, and a high surface area of 221.3 m(2) g(−1). Given its architectural merits, the cellulose II aerogel‐based TENG presents an excellent mechanical response sensitivity and high electrical output performance. By blending with other natural polysaccharides, i.e., chitosan and alginic acid, electron‐donating and electron‐withdrawing groups are introduced into the composite cellulose II aerogels, which significantly improves the triboelectric performance of the TENG. The cellulose II aerogel‐based TENG is demonstrated to light up light‐emitting diodes, charge commercial capacitors, power a calculator, and monitor human motions. This study demonstrates the facile fabrication of cellulose II aerogel and its application in TENG, which leads to a high‐performance and eco‐friendly energy harvesting and self‐powered system.

Tamoxifen was widely applied in the therapy of estrogen receptor (ER)-positive breast cancer. With the purpose of determining the potential impacts of quercetin on its effectiveness, MCF-7 cells were selected as the in vitro model and several cellular biological behaviors (ie, cell proliferation, migration, invasion, cycle, apoptosis, and oxidative stress) were investigated. As results, quercetin showed contrasting dose-response to cellular behaviors dependent on the ROS-regulated p53 signaling pathways. In detail, quercetin promoted cell proliferation and inhibited cell apoptosis at low concentrations, whereas high-concentration resulted in apoptosis induction. Moreover, quercetin at a low concentration significantly inhibited tamoxifen-induced antiproliferation in MCF-7 cells, whereas high concentrations enhanced cell apoptosis in a synergetic manner. The real-time quantitative polymerase chain reaction analysis further implied that quercetin exerted its dual roles in tamoxifen-induced antiproliferative effects by regulated the gene expression involved in cell metastasis, cycle, and apoptosis through the ER pathways. Our present study provides a considerable support to the combination of quercetin and tamoxifen on human ER-positive breast carcinoma management.

Effluent is often treated with ozone before being discharged into a natural water environment. This process will change the interaction between effluent organic matter and pollutants in aquatic environment. The impact of ozonation on complexation between dissolved organic matter in such wastewater and sulfadimidine often found in natural water was studied in laboratory experiments using four types of real wastewater. Ozonation was found to decrease the proportion of organic matter with a molecular weight greater than 5 kDa as well as protein-like, fulvic-like and humic-like components, but except the proportion of hydrophilic components. The aromaticity of the dissolved organic matter was also reduced after ozonation. The complexation of tryptophan and tyrosine with sulfadimidine mainly depends on their hydrophobicity and large molecular weight. Ozonation of fulvic and humic acid tends to produce small and medium molecular weight hydrophilics. The complexation of humic and fulvic acids with sulfadimidine was enhanced by ozonation. Dissolved organic matter, with or without oxidation, were found to weaken sulfadimidine’s inhibition of microbial growth, especially for Aeromonas and Acinetobacter species. This finding will expand our understanding about the impact of advanced treatment processes on the dissolved organic matters’ properties in effluent.

Molybdenum disulfide (MoS

Reclaimed water contains both residual contaminants and pathogenic microorganisms while their simultaneous removal has not been fully addressed. Thus, a photoelectrocatalytical system (PEC) was engineering herein using an innovatively synthesized composite of TiO

Herein, a novel Fe

The DC circuit breaker is the key equipment in the DC power transmission and distribution system. IGCT devices have important application prospects in DC breaking, providing the advantages of large surge current capability and low current conduction losses. Aiming at the on-off electrical characteristics of IGCT, this paper provides the optimized design method for improving the current turn-off capability and reducing the on-state voltage drop of IGCT, in which the GCT longitudinal optimization structure for DC breaking conditions is obtained. Meanwhile, for IGCT compact modular application, the gate unit (GU) is miniaturized and isolated, and GU can be replaced without decompression. Moreover, the GU power supply, series-parallel application and control protection technology optimization are carried out for the practical application requirements. Finally, the validity and feasibility of proposed method are verified by simulation and module test.

We study the existence and nonexistence of traveling waves of diffusive epidemic models with general incidence rates. The model systems are non-monotone because of the intrinsic predator–prey interaction between the susceptible and infective compartments in epidemic systems. Moreover, the incidence rate may not be monotone in the infected population because social behaviors and collective activities may change in response to the prevalence of disease. To find positive traveling solutions of the non-monotone system with a non-monotone incidence function, we will construct a suitable convex set in a weighted function space, and then apply Schauder fixed point theorem. It turns out that the basic reproduction number of the corresponding ordinary differential equations plays an important role in the existence theory of traveling waves. Moreover, the critical wave speed can be explicitly obtained in terms of the diffusion coefficient, recovery rate and death rate for the infected group, and partial derivative of incidence function at the disease-free equilibrium. Finally, we prove that the positive traveling wave solution does not exist if the basic reproduction number is no more than one, or the wave speed is less than the critical value.

Chlorothalonil (CT) is widely used to control fungal diseases, and it is commonly detected in the environment. Phototransformation is an important process which removes CT from aquatic environments. The kinetics and mechanisms of CT photodegradation in solutions with and without humic acid (HA) were investigated, and the influence of dissolved oxygen (DO) on the photodegradation process was also considered. The rate constant observed in pure water was only 0.017 h−1, but it increased to 0.083 h−1 with 5.0 mgC L−1 of HA present. Reactive species generated by HA were shown to play an important role. Moreover, the degradation of CT was promoted at higher HA concentrations. But higher DO concentrations inhibits CT degradation because of the reaction between DO and excited triplet state CT (3CT*) or HA (3HA*). The contributions of the reactive species tested were in the sequence 3HA* > 1O2 > H2O2/O2− ≈ OH in a nitrogen-saturated system, but in an oxygen-saturated system the order was OH ≈1 O2 > H2O2/O2− > 3HA*. 3CT* was confirmed as the active form of CT during degradation, with 4-hydroxy-chlorothalonil and 2,4,5-trichloroisophthalonitrile as the main products. Compared to direct photodegradation, CT photodegradation mediated by HA can decrease the toxicity of an aquatic environment as demonstrated through tests with Scenedesmus obliquus.

In this study, concentrated landfill leachate (CLL) from two-stage DTRO (Disk-Tube Reverse Osmosis) process was treated by co-bioevaporation process with addition of food waste (FW) as the supplementary carbon source. A series of experiments were conducted to explore the feasibility and critical factors of the co-bioevaporation treatment of CLL and FW. The results indicated that the simultaneous removal of water and organic matters contained in CLL and FW mixture was effectively achieved in the co-bioevaporation process, and when the CLL and FW mixing ratio was 1:1.10 (mCLL:mFW), 85.67% of the added water can be evaporated by complete consumption of the organics. Initial moisture content (MC) of 33.9%, dosage of 90%, and air-flow rate (AFR) of 0.035 m3 kg-1TS h-1 were found to be the optimal operating conditions. Water evaporation of 96.7% and volatile solids (VS) consumption of 96.5% were obtained under those optimal conditions during five cycles of co-bioevaporation process.

Hemicelluloses are heteropolysaccharides existing in plant cell wall and seed, and they can be extracted or separated from plants as byproducts during the biomass pretreatment in biorefineries and the pulping in paper industry. The hemicelluloses have many applications such as in biofuels, platform chemicals, and materials. Producing packaging materials (films) is a potential high-value application of the hemicelluloses. However, native hemicelluloses are usually unable to form strong and durable films due to their short chain (low molecular weight), high hydrophilicity, and heterogeneous nature. Chemical and biological modifications could change the physicochemical properties of the hemicelluloses and thereby improve the strength and performance of the hemicellulose-based films. The present review extensively summarized and discussed the recent development and progress in hemicellulose modification strategies and methods for improving the formability and properties of the hemicellulose-based packaging films such as mechanical strength, processability, thermal stability, hydrophobicity, and oxygen and water vapor permeability, which include enzymatic treatment, esterification, etherification, oxidation, coupling, and crosslinking. The challenges and opportunities of hemicellulose as packaging materials were addresses.

This study demonstrated that lignin could be efficiently depolymerized in the solid state with minimal condensation and separated from biomass with high purity by dissolving and hydrolyzing cellulose and hemicelluloses, using an acidic lithium bromide trihydrate (ALBTH) system under mild conditions (with 40 mM HCl at 110 °C). The ALBTH lignins isolated from biomass sources representing the three plant classes (hardwoods, softwoods, and grasses) contained abundant uncondensed moieties (i.e., Hibbert's ketones and benzodioxanes). The benzodioxane structure was identified and confirmed for the first time in an acid-depolymerized lignin. Reactions using lignin model compounds (LMCs, guaiacylglycerol-β-guaiacyl ether and various aromatic monomers) confirmed the formation of the uncondensed moieties and revealed the synergy between LiBr and acid in inducing the crucial intermediate benzyl carbocations, which then led to cleavage of the β-O-4-aryl ether bonds to produce Hibbert's ketones, demethylation to produce benzodioxanes, and condensation reactions. Unlike in the LMC reactions, the condensation of the real lignin in biomass under ALBTH conditions was greatly diminished, possibly due to lignin remaining in the solid state, limiting its mobility and accessibility of the benzyl carbocation to the electron-rich aromatic sites for condensation. Preliminary results indicated that, because of its uncondensed nature, the ALBTH lignin was a good lignin feedstock for hydrogenolysis. This study provided a new approach to effectively isolate depolymerized lignin from lignocellulose in a less condensed form for boosting its downstream valorization.

Alkaline oxidative cracking with molecular oxygen was demonstrated as an effective method to depolymerize lignin under moderate conditions. Ammonia-extracted lignin from corn stover was depolymerized to aromatics and organic acids by the alkaline oxidation. The identified products by GC-MS, NMR, and HPLC included mono-aromatic compounds (such as vanillin, p-coumaric acid, vanillic acid, acetovanillone etc.) and organic acids (such as oxalic, acetic, formic acids, etc.). The overall mass yield of quantified aromatics and organic acids varied from 24% to 58% under the investigated conditions. It was found that the yields and compositions of the products were determined by the reaction conditions (temperature, reaction time, and oxygen pressure). More vanillin and organic acids were produced with oxygen under high temperature and long time, while p-coumaric acid was the primary product under oxygen deficient condition.

Developing low-cost and high-performance biosorbent for water purification continues drawing more and more attention. In this study, cellulose-chitosan composite hydrogels were fabricated via a co-dissolution and regeneration process using a molten salt hydrate (a 60 wt% aqueous solution of LiBr) as a solvent. The addition of chitosan not only introduced functionality for metal adsorption but also increased the specific surface area and improved the mechanical strength of the composite hydrogel, compared to pure cellulose hydrogel. Batch adsorption experiments indicated that the composite hydrogel with 37% cellulose and 63% chitosan exhibited an adsorption capacity of 94.3 mg/g (1.49 mmol/g) toward Cu2+ at 23 °C, pH 5, and initial metal concentration of 1500 mg/L, which was 10 times greater than the adsorption capacity of pure cellulose hydrogel. Competitive adsorption from a mixed metals solution revealed that the cellulose-chitosan composite hydrogel exhibited selective adsorption of the metals in the order of Cu2+ > Zn2+ > Co2+. This study successfully demonstrated an innovative method to fabricate biosorbents from abundant and renewable natural polymers (cellulose and chitosan) for removing metal ions from water.

We report the preparation and conformational property in solution of a library of comb-like poly(propargyl acrylate)-graft-poly(2-ethyl-2-oxazoline) (PPANb-g-PEtOx47-σg) samples with varied grafting densities (σg) ranging from 0 to 0.68. An azido end-functionalized linear poly(2-ethyl-2-oxazoline) (PEtOx-N3) as grafting side chain with a molar mass of 4700 g mol−1 was synthesized by the living cationic ring opening polymerization (CROP) of 2-ethyl-2-oxazoline (EtOx), followed by the sequential post-polymerization azidation modification at the living chain end of PEtOx. Poly(propargyl acrylate) (PPA) as the backbone was prepared by the chemical transformation from the ATRP-made poly(tert-butyl acrylate) (PtBA). Comb-like PPANb-g-PEtOx47-σg samples with different σg were eventually obtained by grafting PEtOx-N3 onto PPA backbone via the copper(I)-catalyzed alkyne-azide cycloaddition (CuAAC) reaction under varied [PEtOx-N3]0/[alkyne]0 ratios. Quadruple-detection size-exclusion chromatography (QD-SEC) system was used to extract the molecular parameters of the obtained comb-like polymers, including molar mass (M), viscometric radius (Rη), and intrinsic viscosity ([η]), etc. The comb-like chain showing a scaling-law of Rη ∼ σg0.34 was confirmed in the shortest backbone, which is fairly accordant with our previous results in polystyrene system. In addition, a transition of polymer shape from star-like to comb-like, and further to branched comb-like structure was observed as the backbone length increases. The transition from star-like to comb-like could be attributed to the continuous increase of length-diameter ratio, which would lead to that the comb-like chain changes its molecular feature from isotropic to anisotropic. On the other hand, the transition from comb-like to branched comb-like should be due to the presence of the intermolecular Glasser-Hay coupling side reactions in comb-like polymers.

The phenolics content and antioxidant activity of walnut (Juglans sigillata Dode) green husks were analysed during different stages of development. Contents of total phenolics and total flavonoids ...

Electron shuttles extensively exist in various environments. Some kinds of organic substances can be applied by microorganisms to produce electrons, and then the electrons can be transferred to other substances or microorganisms through electron shuttles, resulting in coexistence and interaction of diverse species of microbes. In this review, the functional mechanisms of extracellular electron transfer mediated by different electron shuttles are described. And different subtypes as well as the application of electron shuttles in microbial degradation of pollutants, microbial electricity, and the promotion of energy generation are also discussed. Summary results show that extracellular electron transfer is based on the electrogenesis microorganism with the structure of cytochromes or pili. Materials were usually used in long-distance electron transfer because of their widespread presence and abundance. Therefore, the review is beneficial to perceive the pathways of extracellular electron transfer mediated by electron shuttles and explore the contribution of different electron shuttles in extracellular electron transfer.