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1T-phase MoS2, a versatile two-dimensional transition-metal dichalcogenide, is typically synthesized using a one-pot hydrothermal method. However, inadequate control of the sulfurization, reduction, and crystallization processes in the autoclave leads to multilayer 1T-MoS2with high crystallinity, a small surface area, and few defects. Considering the aforementioned issues, a two-stage microreactor continuous hydrothermal flow synthesis (CHFS) system coupled with accurate control and rapid processing is used to prepare 1T-MoS2with abundant voids and a large surface area under 250 °C and 4.0–4.5 MPa. And density functional theory calculations reveal that nitrogenous species, acting as reductants and electron donors, lower the energy of 1T-MoS2by intercalation and surface adsorption, facilitating its swift synthesis within the presulfurization stage for 10 min and reduction stage for 24 min. The precisely controlled synthesis of porous 1T-MoS2, originating from prenucleation clusters, results in a large surface area of 201.5 m2/g, concentrated mesopores of 2–5 nm, and a pore volume of 0.58 cm3/g. Moreover, a significant transformation from the 1T to the 2H phase is prevented by rapid cooling downstream of the CHFS system.

Successful integration of metallic lithium anodes into secondary batteries could enhance energy density and enable new forms of electrified transportation. However, the outlook for widespread lithium metal adoption in energy storage devices remains mixed. This comes in part from existing gaps in our understanding of the relationships connecting the initial state of lithium, its evolution with cycling, and end-of-life state. It remains important to develop standardized protocols for material and cell characterization, cycling performance, safety, and recycling procedures for lithium metal-based batteries. In February 2023 a cohort of scientists and engineers from academia, national laboratories, and industry gathered to converge on a list of critical challenges and action items to provide better understanding of lithium metal evolution and to enhance academic, governmental, and industrial partnerships to address these challenges. Here, we highlight the major discussion topics revolving around the manufacturing of lithium metal, its related metrology and integration into battery form factors, and best practices testing its electrochemical performance relevant to automotive applications. We introduce a power-controlled discharge testing protocol for research and development cells, in alignment between major automotive stakeholders, that may reveal lithium metal battery dynamics closer to practical driving behavior.

Research into kappa opioid receptor (KOR) agonists with attenuated central-nervous-system side effects is a critical focus for developing productive and safe analgesics. Herein, a series of ortho-substituted N-cyclopropylmethyl-7a-phenyl-6,14-endoethano-tetrahydronorthebaines were designed, synthesized, and subjected to bioassays. Compound 7aexhibited high subtype selectivity and potent agonistic activity toward KOR (KOR, Ki= 3.9 nM, MOR/KOR = 270, DOR/KOR = 1075; [35S]GTP?S binding, EC50= 3.4 nM). Additionally, this compound exhibited robust and persistent antinociceptive effects in rodent models with different animal strains (hot plate test, ED50= 0.20–0.30 mg/kg, i.p.; abdominal constriction test, ED50= 0.20–0.60 mg/kg, i.p.), with its KOR-mediated mechanism for antinociception firmly established. Notably, compound 7a, unlike conventional KOR agonists, displayed minimal sedation and aversion at the antinociceptive ED50dose. This feature addresses a crucial limitation in existing KOR agonists, positioning compound 7aas a promising novel therapeutic agent.

Flooding of paddy fields during the rice growing season enhances arsenic (As) mobilization and greenhouse gas (e.g., methane) emissions. In this study, an adsorbent for dissolved organic matter (DOM), namely, activated carbon (AC), was applied to an arsenic-contaminated paddy soil. The capacity for simultaneously alleviating soil carbon emissions and As accumulation in rice grains was explored. Soil microcosm incubations and 2-year pot experimental results indicated that AC amendment significantly decreased porewater DOM, Fe(III) reduction/Fe2+release, and As release. More importantly, soil carbon dioxide and methane emissions were mitigated in anoxic microcosm incubations. Porewater DOM of pot experiments mainly consisted of humic-like fluorophores with a molecular structure of lignins and tannins, which could mediate microbial reduction of Fe(III) (oxyhydr)oxides. Soil microcosm incubation experiments cospiking with a carbon source and AC further consolidated that DOM electron shuttling and microbial carbon source functions were crucial for soil Fe(III) reduction, thus driving paddy soil As release and carbon emission. Additionally, the application of AC alleviated rice grain dimethylarsenate accumulation over 2 years. Our results highlight the importance of microbial extracellular electron transfer in driving paddy soil anaerobic respiration and decreasing porewater DOM in simultaneously remediating As contamination and mitigating methane emission in paddy fields.

The use of contrastive learning (CL) in recommendation has advanced significantly. Recently, some works use perturbations in the embedding space to obtain enhanced views of nodes. This makes the representation distribution of nodes more even and then improve recommendation effectiveness. In this article, the authors provide an explanation on the role of added noises in the embedding space from the perspective of invariant learning and feature selection. Guided by this thinking, the authors devise a more reasonable method for generating random noises and put forward web semantic based robust graph contrastive learning for recommendation via invariant learning, a novel graph CL-based recommendation model, named RobustGCL. RobustGCL, randomly zeros the values of certain dimensions in the noise vectors at a fixed ratio. In this way, RobustGCL can identify invariant and variant features and then learn invariant and variant representations. Tests on publicly available datasets show that our proposed approach can learn invariant representations and achieve better performance.

Background: Papillary thyroid cancer (PTC) is the most common thyroid tumor (TC). However, there is still a lack of effective indicators for PTC detection and prognosis. We intended to find a novel tumor marker for the progression of PTC. Methods: The expression of circRNAs was measured by quantitative real-time polymerase chain reaction (qRT-PCR). SiRNA transfection was used to knockdown the expression of hsa_circ_0010023 in K1 cells. Cell proliferation was evaluated using cell counting and CCK8. Cell apoptosis was analyzed using flow cytometry. Hsa_circ_0010023 downstream pathways were predicted with bio-informatics analysis. The miR-1250-5p and MAPK1 were measured by qRT-PCR. The interaction between miR-1250-5p and hsa_circ_0010023 was vertified by dual-luciferase reporter assay. Results: Among the four circRNAs screened, only hsa_circ_0010023 and hsa_circ_0128482 were highly expressed in PTC (P< 0.05). The expression of hsa_circ_0010023 was significantly correlated with lymph node metastasis and extrathyroid infiltration (P< 0.05). Compared with the control group, the cell proliferation of the si-circ-0010023 group was significantly inhibited (P< 0.05). Knockdown of hsa_circ_0010023 promotes apoptosis of K1 cells (P< 0.001). The expression of hsa_circ_0010023 was negatively correlated with miR-1250-5p and positively correlated with MAPK1. MiR-1250-5p overexpression significantly reduced the luciferase activity of wild type plasmid (hsa_circ_0010023 WT), but not that of mutant type plasmid (hsa_circ_0010023 MUT). Conclusion: The expression level of hsa_circ_0010023 was positive related to the progression of PTC, and hsa_circ_0010023 may promote PTC through sponging miR-1250-5p. Hsa_circ_0010023 may be a potential bio-marker for the diagnosis of PTC.

The urban composite ecosystem was broken down into three daughter systems of nature, economics, and society to prevent the uncertainty of results arising from the disagreement of assessment indices. In addition, the traditional method for emergy analysis was improved and integrated with the fuzzy clustering model in order to provide a new method for the proper evaluation of the health of urban ecosystems from the perspective of energy-material coupling. With this new method, the health of urban ecosystem in Changchun, China was evaluated. Results showed that by continuously adjusting the energy structure, the industry structure, and the development mode, the urban ecosystem of Changchun City gradually transitioned from the unhealthy to the healthy status. However, a membership value of only 0.77 indicated the weak health of the ecosystem where the environmental load rate gradually increased every year. Emergy analysis using the fuzzy clustering integration model demonstrated the whole health status of urban composite systems with a certain degree of operability and replicability.

Iron (oxyhydr)oxides and organic matter (OM) are intimately associated in natural environments, and their fate might be linked to sulfur during sulfidation–reoxidation cycling. However, the coupling of DOM molecular fractionation with Fe and S transformations following a full sulfidation–reoxidation cycle remains poorly understood. Here, we reacted Fh and Fh–OM associations with S(−II) anaerobically and then exposed the sulfidic systems to air. S(−II) preferentially reacted with Fh to form inorganic S (e.g., mackinawite, S0, and S22–) over being incorporated into OM as organic S and therefore indirectly affected OM fate by altering Fe speciation. Fh sulfidation was inhibited by associated OM, and the main secondary Fe species were mackinawite, Fe(II)–OM compounds, and lepidocrocite. Concomitantly, organic molecules high in unsaturation, aromaticity, and molecular weight were detached from solid-phase Fe species due to their lower affinities for secondary Fe species than for Fh. During the reoxidation stage, the previously formed Fe(II) species were reoxidized to Fh with a stronger aggregation, which recaptured formerly released OM with higher selectivity. Additionally, •OH was generated from Fe(II) oxygenation and degraded a portion of the DOM molecules. Overall, these results have significant implications for Fe, C, and S cycling in S-rich environments characterized by oscillating redox conditions.

The sol–gel process has attracted extensive attention for the preparation of advanced inorganic materials. Notably, solvent extraction significantly affects the properties of the final products. However, the poor controllability of the extraction process generally limits the use of solvent extraction technology in regulating the morphologies and structures of inorganic materials. In this study, we successfully constructed a two-stage microfluidic chip, which decoupled the sol droplet generation and extraction solidification processes and realized highly controllable extraction. The influence of flow field parameters on the diffusion of the extractant was investigated via in situ observations, particle image velocimetry, and computational fluid dynamics simulations, which could induce changes in the microsphere morphologies by regulating the extraction diffusion rate. Rapid diffusion of the extractant was found to be beneficial for maintaining sphericity, whereas slow diffusion induced directional deformation in the microspheres. In addition, we revealed the transformation process of the internal microstructure. 1-Nonanol was found to be conducive to the formation of gel networks and long fibers, whereas n-butanol was found to be conducive to the directional ordering of fibers under droplet circulation. Polymorphous hundred-micron alumina microspheres (such as spherical, ravine ellipsoid, erythrocyte, and valve types) were successfully prepared using microfluidic-assisted solvent diffusion and extraction processes.

The nitration of toluene with mixed acid is one of the most representative nitration reactions. Accurate kinetic study is essential for controlling the reaction and designing reactors. Due to the characteristics of fast rate, high exothermicity and heterogeneity in toluene nitration, the effects of mass and heat transfer may result in inaccurate determination of kinetics. In this work, the adiabatic temperature rises of the reaction system were studied to provide precise ranges of experimental conditions for accurately controlling the reaction rate and heat release rate in a liquid–liquid microflow system. The adiabatic temperature rise was successfully controlled to below 0.3 °C. The effects of mass and heat transfer on the reaction rate were completely eliminated, so that the kinetic study was carried out under the control of intrinsic kinetics only. The activation energy for toluene nitration was determined to be 28.00 kJ/mol. The activation energies for the formation of o-nitrotoluene and p-nitrotoluene were obtained for the first time, which were 25.71 and 31.91 kJ/mol, respectively. The obtained kinetic models can predict the reaction performance of toluene nitration very well.

Seamless prediction is a weather–climate integrated prediction covering multiple time scales that include days, weeks, months, seasons, years, and decades. Seamless prediction can provide different industries with information such as weather conditions and climate variations from the next few days to years, which have important impacts on economic and social development and important reference value for short-, medium- and long-term decision-making and planning of the country. Therefore, seamless prediction has received widespread attention from the international scientific community recently. As Chinese scientists have also carried out relevant research, this paper reviews the research in China on developments and applications of seamless prediction methods and prediction systems in recent years. Among them, the main progress of seamless prediction methods studies is reviewed from four aspects: short- and medium-range weather forecasting, subseasonal-to-seasonal, seasonal-to-interannual, and decadal climate prediction. In terms of development and application of seamless prediction systems, the main achievements made by meteorological operational departments, scientific institutes, and universities in China in recent years are reviewed. Finally, some of the issues in seamless prediction that need further study are discussed.

Ship propellers suffered from serious coupling damage of cavitation-erosion (CE) and corrosion when operated with high-speed in the marine environment. To improve the CE-corrosion resistance of the Ni–Al bronze (NAB) propeller alloy, a novel Cu-based medium-entropy alloy coating (Cu55Al20Ni12Ti8Si5, at.%) was prepared by high-velocity oxygen-fuel spraying technology in this study. The characteristics and CE behavior of coating and NAB were comparatively investigated, then the CE damage mechanism was discussed by analyzing CE damage morphologies. The influence of CE on corrosion behavior and the coupling effect between CE and corrosion were further elucidated by electrochemical corrosion experiments. The results indicated that the as-sprayed coating mainly comprised of BCC solid solution phase and NiTi-rich precipitates, which possessed higher hardness (6.73 ± 1.23 GPa) and superior resilience (27.0%) than the NAB. The cumulative mass loss rate for the coating after 18 h CE in distilled water and 3.5 wt.% NaCl solution was only 38.7% and 80.6% that for the NAB, revealing the better anti-CE performance of the coating. The preferential CE of the BCC matrix around the NiTi-rich precipitates, fatigue fracture and lamellar spalling were summarized as the main CE damage mechanism for the coating in 3.5 wt.% NaCl solution. CE had a significant influence on corrosion behavior of coating and NAB, which resulted in corrosion performance degradation of both two materials. The CE-corrosion coupling effect led to the remarkable mass loss, and mechanical effect rather than corrosion effect was ascribed to be the dominated factor for the damage of coating and NAB.

Various hollowing substrates have been invented to equipped in the embedded cooling power modules. Through a lower stress residue, multilayer nanosilver paste ensemble pressureless sintering to obtain the qualified thermal interface material (TIM) joints becomes an essential process for those fragile stacking packages. As the Anand viscoelastic constitutive model prediction, the maximum residual stress inside the TIM joints is only 63.18 MPa, far below the encapsulated materials’ tensile strengths. From all the scanning electron microscope (SEM), X-ray, and scanning acoustic microscope (SAM) image investigations, the upper and beneath nanosilver paste ensemble pressureless sintered TIM joints (50 $\pm ~10~\mu \text{m}$ thickness) contained few cracks and delamination (only 1.6% ± 0.1% and 8.5% ± 0.1% void ratios, respectively). The measured upper and beneath sintered TIM joints’ bond strengths were up to 38 ± 2 and 63.8 ± 2 MPa, higher than the industry requirement (30 MPa), respectively. After 21 000 power cycles, the upper and beneath sintered TIM joints’ thermal resistance increased only by 10.3% and 5.3%, far underneath the failure standard (20%), respectively. This presented multilayer nanosilver paste ensemble pressureless sintering process is a promising technology for the embedded cooling power module stacking package.

Cadmium sulfide nanoparticles (CdS-NPs) can be formed prevalently in the environment viamicrobial transformation of anthropogenic Cd(ii). The behavior of CdS-NPs in various natural processes is a key factor controlling their stability and the release of toxic Cd(ii). However, the microscopic kinetics are poorly understood due to the complexity of the intrinsic morphology- and facet-dependent NP surface processes, which are further complicated by environmental matrix effects. In this study, we investigated the stability of three CdS-NPs (CdS-sphere, CdS-rod, and CdS-sheet) and one nanosized biogenic CdS (Bio-CdS NPs) in Cu(ii) spiked solutions using combined kinetic, spectroscopic, HRTEM and DFT approaches. Cd(ii) was quickly released (2.578–14.547 mmol L−1h−1m−2) by Cd/Cu cation exchange, especially for CdS-sheet (5.945–13.789 mmol L−1h−1m−2), and the morphologies of CdS-NPs were preserved after the cation exchange. Additionally, the cation exchange on CdS-NP surfaces was influenced by the coexisting DOM and reducing substances. In terms of DOM, the complexation of Cu(ii) with DOM decreased the free Cu(ii) ions in solutions, thus the cation exchange on the CdS-NP surfaces with Cu(ii) was inhibited in the presence of DOM. Conversely, the presence of reducing substances promoted the dissolution of CdS-NPs due to the formation of chalcophile Cu(i), forming more chemically stable Cu2S and releasing the lattice Cd(ii). The results of HRTEM and DFT calculations confirmed that the cation exchange occurred preferentially on the CdS-NP {001} facet, forming CdS/CuS heterostructures with covellite CuS growing at the ends along the [002] direction of CdS. Altogether, these findings have important geochemical significance as the facet-dependent transformation of metal sulfides is consequential in complex natural and anthropogenic environments.

Phosphorus is an essential element for plant metabolism and growth, but its future supply under elevated levels of atmospheric CO2remains uncertain. Here we present measurements of phosphorus concentration from two long-term (15 and 9 years) rice free air carbon dioxide enrichment experiments. Although no changes were observed in the initial year of the experiments, by the end of the experiments soil available phosphorus had declined by more than 20% (26.9% and 21.0% for 15 and 9 years, respectively). We suggest that the reduction can be explained by the production of soil organic phosphorus that is not in a readily plant-available form, as well as by increased removal through crop harvest. Our findings further suggest that increased transfers of plant available phosphorus from biological, biochemical and chemical phosphorus under anthropogenic changes are insufficient to compensate for reductions to plant available phosphorus under long-term exposure to elevated CO2. We estimate that reductions to rice yields could be particularly acute in low-income countries under future CO2scenarios without the input of additional phosphorus fertilizers to compensate, despite the potentially reduced global risk for phosphorus pollution.

[Display omitted] • A highly-efficient extractant, cyclohexanone, was proposed. • Molecular level reasons for its good performances were investigated. • The interactions between extractants and phenolic compounds were studied. • The effects of concentration, temperature and pH values on extraction were explored. Methyl isobutyl ketone (MIBK) and diisopropyl ether (DIPE) are two commonly used extractants in industry, but their efficiency in extracting phenols, especially polyhydroxyphenols, is low. In the work, a highly-efficient extractant was proposed to extract phenolic compounds, including polyhydroxyphenols. The interactions between three extractants, cyclohexanone (CYC), MIBK and DIPE, and phenols were analyzed by the COSMO-RS method and CYC shows stronger interactions with phenols than MIBK and DIPE. The results of Fourier-transform infrared spectroscopy (FTIR) show that strong hydrogen bonds are formed between CYC and phenolic compounds, in agreement with the results of the COSMO-RS method. The effects of concentration, temperature and pH values on the extractant performance were studied. Results showed that the performance of CYC is the best, followed by MIBK and DIPE, whose performance is the worst. As CYC was used as the extractant, the distribution coefficients of the three phenolic compounds, phenol, resorcinol and phloroglucinol, are 96.7, 47.8, 13.0, respectively. These values are 35%, 263%, and 160% larger than those of phenol, resorcinol and phloroglucinol, respectively, corresponding to MIBK. CYC is a highly-efficient extractant for the extraction of phenolic compounds, including polyhydroxyphenol. [ABSTRACT FROM AUTHOR]

Nanoplastics are ubiquitous in ecosystems and impact planetary health. However, our current understanding on the impacts of nanoplastics upon terrestrial plants is fragmented. The lack of systematic approaches to evaluating these impacts limits our ability to generalize from existing studies and perpetuates regulatory barriers. Here, we undertook a meta-analysis to quantify the overall strength of nanoplastic impacts upon terrestrial plants and developed a machine learning approach to predict adverse impacts and identify contributing features. We show that adverse impacts are primarily associated with toxicity metrics, followed by plant species, nanoplastic mass concentration and size, and exposure time and medium. These results highlight that the threats of nanoplastics depend on a diversity of reactions across molecular to ecosystem scales. These reactions are rooted in both the spatial and functional complexities of nanoplastics and, as such, are specific to both the plastic characteristics and environmental conditions. These findings demonstrate the utility of interrogating the diversity of toxicity data in the literature to update both risk assessments and evidence-based policy actions.

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Phytoremediation is a potentially cost-effective and environmentally friendly remediation method for environmental pollution. However, the safe treatment and resource utilization of harvested biomass has become a limitation in practical applications. To address this, a novel manganese-carbon-based single-atom catalyst (SAC) method has been developed based on the pyrolysis of a manganese hyperaccumulator, Phytolacca americana. In this method, manganese atoms are dispersed atomically in the carbon matrix and coordinate with N atoms to form a Mn–N4structure. The SAC developed exhibited a high photooxidation efficiency and excellent stability during the degradation of a common organic pollutant, rhodamine B. The Mn–N4site was the active center in the transformation of photoelectrons via the transfer of photoelectrons between adsorbed O2and Mn to produce reactive oxygen species, identified by in situ X-ray absorption fine structure spectroscopy and density functional theory calculations. This work demonstrates an approach that increases potential utilization of biomass during phytoremediation and provides a promising design strategy to synthesize cost-effective SACs for environmental applications.

The photochemical properties of paddy water might be affected by the commonly used amendments in rice fields owing to the associated changes in water chemistry; however, this important aspect has rarely been explored. We examined the effects of agricultural amendments on the photochemistry of paddy water during rice growth. The amendments significantly influenced the photogenerated reactive intermediates (RIs) in paddy water, such as triplet dissolved organic matter (3DOM*), singlet oxygen, and hydroxyl radicals. Compared with control experiments without amendments, the application of straw and lime increased the RI concentrations by up to 16.8 and 11.1 times, respectively, while biochar addition had limited effects on RI generation from paddy water in in situ experiments under sunlight. Fluorescence emission–excitation matrix spectroscopy, Fourier transform ion cyclotron resonance mass spectrometry, and structural equation modeling revealed that upon the addition of straw and lime amendments, humified DOM substances contained lignins, proteins, and fulvic acids, which could produce more RIs under irradiation. Moreover, the amendments significantly accelerated the degradation rate of 2,4-dichlorophenol but led to the 3DOM*-mediated formation of more toxic and stable dimeric products. This study provides new insights into the effects of amendments on the photochemistry of paddy water and the pathways of abiotic degradation of organic contaminants in paddy fields.

This review systematically summarizes the source of electricity, the key choice of catalyst, and the potentiality of electrolyte for prospective hydrogen generation.Each section provides comprehensive overview, detailed comparison and obvious advantages in these system configurations.The problems of hydrogen generation from electrolytic water splitting and directions of next-generation green hydrogen in the future are discussed and outlooked.

Nanoparticulate mercury (Hg-NPs) are ubiquitous in nature. However, the lack of data on their concentration in soils impedes reliable risk assessments. This is due to the analytical difficulties resulting from low ambient Hg concentrations and background interferences of heterogeneous soil components. Here, coupled to single particle inductively coupled plasma-mass spectrometry (spICP-MS), a standardized protocol was developed for extraction and quantification of Hg-NPs in natural soils with a wide range of properties. High particle number-, particle mass-, and total mass-based recoveries were obtained for spiked HgS-NPs (74–120%). Indigenous Hg-NPs across soils were within 107–1011NPs g–1, corresponding to 3–40% of total Hg on a mass basis. Metacinnabar was the primary Hg species in extracted samples from the Wanshan mercury mining site, as characterized by X-ray absorption spectroscopy and transmission electron microscopy. In agreement with the spICP-MS analysis, electron microscopy revealed comparable size distribution for nanoparticles larger than 27 nm. These indigenous Hg-NPs contributed to 5–65% of the measured methylmercury in soils. This work paves the way for experimental determinations of indigenous Hg-NPs in natural soils, which is critical to understand the biogeochemical cycling of mercury and thereby the methylation processes governing the public exposure to methylmercury.

In order to study the adsorption performance of modified cellulose on Cd(II) in wastewater, cellulose was extracted from corn straw by the extraction method of nitric acid-ethanol, and three modified cellulose materials, that is, chitosan-cellulose (Cell-CS), citric acid-cellulose (Cell-CA) and chitosan/citric acid-cellulose (Cell-CA-CS) were prepared by single and compound modification of chitosan and citric acid. The adsorption properties of modified cellulose materials for Cd(II) in water were studied by laboratory simulation. The results from the structure characterization with Fourier-transform infrared spectroscopy, scanning electron microscopy and energy-dispersive X-ray spectroscopy showed that the group of C=O occurred on the surface of Cell-CA, chitosan particles were attached to the surface of Cell-CS; Cell-CA-CS was being of the structural characteristics of both of Cell-CS and Cell-CA. The results from the adsorption test showed that the adsorption kinetic characteristics of Cd(II) in water can be described by pseudo-second-order kinetic model, and the adsorption thermodynamic characteristics can be described by Langmuir equation. The adsorption capacity of cellulose materials for Cd(II) in water was in the order of Cell-CA-CS > Cell-CS > Cell-CA > Cell. The result from the five times of adsorption-regeneration showed that Cell-CA-CS still had a large adsorption capacity for Cd(II) in water and consequently had great potential for the treatment of Cd(II) containing wastewater.

The activation of peroxymonosulfate (PMS) by metal-doped C–N-based materials has been used extensively for pollutant degradation but usually suffers from low efficiency and stability due to the relatively few N coordination sites, particularly for the degradation of persistent organic pollutants (POPs). To overcome these issues, we have developed a novel N site-abundant C3N5doped with cobalt for PMS activation to degrade a typical POP (2,4,4′-trichlorobiphenyl, PCB28). It was found that cobalt-doped C3N5(Co-C3N5) exhibited high activity towards activating PMS for the complete degradation of PCB28 within 30 min (kobs= 0.1998 min−1), which was 11.8–27.8 times higher than that with conventional metal-based persulfate activation processes. X-ray absorption fine structure (XAFS) spectroscopy, electron paramagnetic resonance (EPR), high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), density functional theory (DFT) calculations, and radical quenching experiments were combined to clarify the activation mechanism of PMS by Co-C3N5. It was unveiled that isolated single Co atoms coordinated by pyridinic N (Co–N4) were the main active sites for the catalytic decomposition of PMS to produce sulfate radicals for contaminant degradation. In addition, Co-C3N5has stable catalytic performance with limited Co dissolution within five cycles over a wide range of pH values. This study provides a novel strategy to design highly effective metal-doped C–N-based catalysts for PMS-based advanced oxidation technologies for environmental remediation.

Nitrous acid (HONO) is an important photochemical precursor to hydroxyl radicals particularly in an urban atmosphere, yet its primary emission and secondary production are often poorly constrained. Here, we measured HONO and nitrogen oxides (NOx) at both the inlet and the outlet in a busy urban tunnel (>30 000 vehicles per day) in south China. Multiple linear regression revealed that 73.9% of the inlet–outlet incremental HONO concentration was explained by NO2surface conversion, while the rest was directly emitted from vehicles with an average HONO/NOxratio of 1.31 ± 0.87%, which was higher than that from previous tunnel studies. The uptake coefficient of NO2, γ(NO2), on the tunnel surfaces was calculated to be (7.01 ± 0.02) × 10–5, much higher than that widely used in models. As tunnel surfaces are typical of urban surfaces in the wall and road materials, the dominance of HONO from surface reactions in the poorly lit urban tunnel demonstrated the importance of NO2conversion on urban surfaces, instead of NO2conversion on the aerosol surface, for both daytime and night-time HONO even in polluted ambient air. The higher γ(NO2) on urban surfaces and the elevated HONO/NOxratio from this study can help explain the missing HONO sources in urban areas.

This study presents a scientometric analysis on biochar research to investigate the research status and developments as well as future trends in this field in 2020. A total of 3671 publications were retrieved from the Web of Science core collection database in 2020, which were analyzed for categories, countries, authors, and keywords. China and USA played a leading role in the research of biochar. Yong Sik Ok and Daniel C. W. Tsang were the most prolific authors in the application of biochar in agriculture, environment, and energy. Based on the keywords clustering analysis, biochar applications in “bioenergy production”, “global climate change mitigation”, “salinity and drought stress amelioration”, “organic pollutants degradation”, “heavy metals immobilization”, and “bioremediation” were the main hotspots. Biochar for salinity and drought stress amelioration became the focus in biochar area in 2020 as biochar amendment had great potential in alleviating salt- and drought-affected soils. Organic pollutants’ degradation via advanced oxidation process (AOPs) represents a sustainable growing topic. Radical and non-radical pathways were summarized for AOPs. Bioremediation using functional bacteria (e.g., heavy metal-resistant bacteria and organic pollutant-degraders) immobilized on biochar was still a research hotspot. Immobilized cells showed excellent performance in removing various contaminants by combining the advantages of highly efficient physiochemical sorption of biochar and microbial metabolisms. The review improves our understanding on scientific advances and potential future research directions in biochar research.

Zigzag is a classic microchannel configuration with unique modifiable geometric parameters (bending angles and overlapped regions) compared with other serpentine geometries. It provides an additional potential for application-oriented micromixer design. In this work, diverse novel three-dimensional (3D) zigzag micromixer configurations were proposed and investigated based on classic zigzag planar geometries. These micromixers consist of misaligned inlet junction parts and 3D zigzag mixing parts with various bending angles and overlapped regions. The mixing performance, mixing mechanism, and pressure drop characteristics of these micromixers were investigated by numerical simulation. Furthermore, selected 3D micromixer geometries were fabricated into polyimide-based microfluidic chips by efficient and low-cost manufacturing techniques. The Villermaux–Dushman experiment has been conducted in these customized chips, which exhibits promising prospects in biochemical applications.

Microbial-mediated transformation of anthropogenic Cd2+controls its distribution, bioavailability, and potential risks. However, the processes readily form CdS nanoparticles (CdS-NPs), which exhibit dissolution behavior different from that of larger sized particles. Here, we investigated the effects of morphologies and facets of CdS-NPs on their photoinduced dissolution. Three CdS-NPs, CdS-sphere, CdS-rod, and CdS-sheet, and one nanosized biogenic CdS (Bio-CdS) were synthesized with different dominant facets of {101}, {100}, {001}, and {111} and thus distinct surface chemistry. As explored by HRTEM, EPR, and DFT calculations, photogenerated e–/h+pairs were more likely to generate on CdS-sheet surfaces due to higher surface energies and a narrower band gap, facilitating the formation of •OH and thereby faster dissolution (kobs= 6.126–6.261 × 10–2h–1). The wider band gaps of CdS-sphere and CdS-rod caused less formation of O2•–and •OH, leading to slower oxidative dissolutions (kobs= 0.090–0.123 and 2.174–3.038 × 10–2h–1, respectively). Given the similar surface energy as that of CdS-sheet, the dissolution rate of Bio-CdS was close to that of CdS-rod and CdS-sheet, which was 1.6–3.5 times faster than that of larger sized CdS, posing higher environmental risks than thought. Altogether, this work revealed the facet effects on the dissolution of CdS-NPs, manifesting a deeper understanding of metal sulfides’ environmental behaviors.

The search for selective kappa opioid receptor (κOR) agonists with an improved safety profile is an area of interest in opioid research. In this work, a series of m-substituted analogs were designed, synthesized, and assayed, resulting in the identification of compound 6c(SLL-1206) as a κOR agonist with single-digit nanomolar activities. The subtype selectivity of compound 6cappeared to be a consequence of an enormous decrease in the affinity for μOR and δOR, rather than a significant increase in the affinity for κOR, which was not the case for SLL-039, another selective and potent κOR agonist identified in our previous work. Besides reduced central nervous system effects, SLL-1206exhibited substantially improved physicochemical and pharmacokinetic properties compared with SLL-039, with increases of over 20-fold in aqueous solubility and approximately 40-fold in oral bioavailability in rats.

A tapered As_2S_3 photonic crystal fiber (PCF) with four layers of air holes in a hexagonal array around the core is designed in this paper. Numerical simulation shows that the dispersion D decreases and the nonlinearity coefficient γ increases from the thick to the thin end along the tapered PCF. We simulate the midinfrared pulse compression in the tapered As_2S_3 PCF using the adaptive split-step Fourier method. Initial Gaussian pulses of 4.4 ps and a central wavelength of 2.5 μm propagating in the tapered PCF are located in the anomalous dispersion region. With an average power of assumed input pulses at 3 mW and a repetition frequency of 81.0 MHz, we theoretically obtain a pulse duration of 56 fs and a compression factor of 78 when the pulse propagates from the thick end to the thin end of the tapered PCF. When confinement loss in the tapered PCF is included in the simulation, the minimum pulse duration reaches 72 fs; correspondingly, the maximum compression factor reaches 61. The results show that in the anomalous-dispersion region, midinfrared pulses can be efficiently compressed in a dispersion-decreasing and nonlinearity-increasing tapered As_2S_3 PCF. Due to confinement loss in the tapered fiber, the efficiency of pulse compression is suppressed.