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Single-atom catalysts (SACs) with well-defined and specific single-atom dispersion on supports offer great potential for achieving both high catalytic activity and selectivity. Covalent organic frameworks (COFs) with tailor-made crystalline structures and designable atomic composition is a class of promising supports for SACs. Herein, we have studied the binding sites and stability of Pd single atoms (SAs) dispersed on triazine COF (Pd1/trzn-COF) and the reaction mechanism of CO oxidation using the density functional theory (DFT). By evaluating different adsorption sites, including the nucleophilic sp2 C atoms, heteroatoms and the conjugated π-electrons of aromatic ring and triazine, it is found that Pd SAs can stably combine with trzn-COF with a binding energy around −5.0 eV, and there are two co-existing dynamic Pd1/trzn-COFs due to the adjacent binding sites on trzn-COF. The reaction activities of CO oxidation on Pd1/trzn-COF can be regulated by the anion-π interaction between a + δ phenyl center and the related −δ moieties as well as the electron-withdrawing feature of imine in the specific complexes. The Pd1/trzn-COF catalyst is found to have a high catalytic activity for CO oxidation via a plausible tri-molecular Eley-Rideal (TER) reaction mechanism. This work provides insights into the d-π interaction between Pd SAs and trzn-COF, and helps to better understand and design new SACs supported on COF nanomaterials.

Summary Atomically dispersed Fe–N–C catalyst has shown great performance in the CO2-to-CO conversion, yet the high CO selectivity is achieved only within a rather narrow potential range, which cannot well meet the requirements for the following CO dimerization or hydrogenation. Here, we developed a hydrogen-pyrolysis etching strategy to precisely manipulate the uncoordinated N dopants in the Fe–N–C catalyst. This strategy could preferentially eliminate pyridinic and pyrrolic N atoms while leaving graphitic N. The resulting catalyst gave a CO faradaic efficiency (FECO) above 90% over a broad window from −0.3 to −0.8 V (versus RHE) (in particular, FECO > 97% at −0.6 V). In situ ATR-SEIRAS and first-principle calculations further revealed that this strategy can not only suppress the parasitic H2 generation but also promote CO2 activation and protonation with the assistance of co-adsorbed H2O on the “atomic interface” of “FeN4/graphitic N.”

The hydrogen evolution reaction (HER) via water electrolysis has gained immense research attention. Seawater electrolysis provides great opportunities for sustainable energy production, but is extremely challenging. Transition metal phosphides are promising candidate electrocatalysts. Herein, we prepared a novel Fe–Co2P bundle of nanorods (BNRs) for catalyzing the HER in seawater electrolysis and over the entire pH range. Cobalt phosphides with different crystal phases and morphologies were obtained by varying the Fe doping amount. The Co:Fe molar ratio of 1:0.5 was found to be optimum. The Fe doping improved the HER performance of Co2P over the entire pH range by providing favorable electronic properties and morphology, lattice distortion, and special coordination environment. The Fe-Co2P BNRs showed higher catalytic activity than 20% Pt/C in seawater at high potentials. The density functional theory calculations revealed that the Fe doping reduced the hydrogen binding strength of Co2P to efficiently accelerate the HER kinetics and produce a favorable charge density. This study provides valuable insights into the design and development of high-efficiency HER catalysts for large-scale seawater electrolysis.

Polymerization-induced self-assembly (PISA) has been established as an efficient method to fabricate polymeric vesicles. In most PISA cases, the formation of vesicles is solely driven by the solvop...

Designing a highly active- and stable non-noble metal bifunctional oxygen catalyst for rechargeable Zn-air battery remains a great challenge. Herein, we develop a facile and melamine-assisted-pyrolysis (MAP) strategy for the synthesis of core–shell Co-based electrocatalysts@N-doped carbon nanotubes (Co@CNTs) derived from metal–organic frameworks. The Co@CNTs exhibited excellent bifunctional electrocatalytic performance for both oxygen evolution and reduction. DFT calculations demonstrated that the Gibbs free energy of the rate-determining step was small enough to improve ORR activities. As a result, a Zn-air battery assembled with Co@CNTs proves a lager power density, low voltage gap between charge–discharge and excellent stability. Thus, this work offers a facile strategy to realize the synthesis of non-noble metal electrocatalyst for Zn-air battery materials with high electrochemical performance.

Lysosomes are integration hubs for several signaling pathways, such as autophagy and endocytosis, and also crucial stores of ions, including Zn2+. Lysosomal dysfunction caused by changes in their morphology by fusion and fission processes can result in several pathological disorders. However, the role of Zn2+ in modulating the morphology of lysosomes is unclear. The resolution of conventional epifluorescence microscopy restricts accurate observation of morphological changes of subcellular fluorescence punctum. In this study, we used a modified epifluorescence microscopy to identify the center of a punctum from a series of z-stack images and calculate the morphological changes. We stained primary cultured rat embryonic cortical neurons with FluoZin3, a Zn2+-sensitive fluorescent dye, and Lysotracker, a lysosome-specific marker, to visualize the distribution of Zn2+-enriched vesicles and lysosomes, respectively. Our results revealed that treating neurons with N,N,N′,N′-tetrakis(2-pyridylmethyl)ethylenediamine, a cell-permeable Zn2+ chelator, shrank Zn2+-enriched vesicles and lysosomes by up to 25% in an hour. Pretreating the neurons with YM201636, a blocker of lysosome fission, could suppress this shrinkage. These results demonstrate the usefulness of the modified epifluorescence microscopy for investigating the homeostasis of intracellular organelles and related disorders.

In comparison with the post-polymerization cross-linking strategy, in situ cross-linking by divinyl comonomers in polymerization-induced self-assembly (PISA) is a more straightforward and convenient approach to produce structurally stabilized nano-objects. However, cross-linking usually lowers the chain mobility and hence prevents morphology transition, so formation of higher order morphologies (worm-like micelles or vesicles) by the in situ cross-linking strategy in PISA has always been a great challenge. In this work, not only cross-linked structures but also a promoting effect on morphology transition has been observed during the in situ cross-linking PISA. Worm-like micelles, lamella and vesicles with stabilized (cross-linked) structures are produced by RAFT dispersion copolymerization of 2-(diisopropylamino)ethyl methacrylate (DIPEMA) and the divinyl comonomer cystaminebismethacrylamide (CBMA). The morphology transition is not prevented due to the slower consumption of CBMA than that of the DIPEMA, and the cross-linking process is mostly delayed to the late stage of polymerization. What is surprising, compared with RAFT dispersion polymerization of DIPEMA in the absence of CBMA, is that polymeric nano-objects with higher order morphologies are generated in most cases of the RAFT dispersion copolymerization of DIPEMA and CBMA. The slower consumption of CBMA generates branched structures of the solvophobic blocks, which significantly promote the morphology transition. Cleavage of the cross-linkers (disulfide linkage) by incubating with glutathione (GSH) leads to the morphology transition of the nano-objects to the lower order ones, which further demonstrates the promoting effect on morphology transition in in situ cross-linking PISA.

A multicyclic polymer with a hyperbranched structure was successfully synthesized. A tailored initiator containing a protected alkynyl group was prepared and used to initiate the atom transfer radical polymerization (ATRP) of styrene. By the combination of a click reaction, a UV-induced coupling reaction and post-modification, an AB2 type cyclic polystyrene with a protected alkynyl group and two azide groups was obtained, and after deprotection, the clickable cyclic polymer was used as a macromonomer to prepare a multicyclic polymer with a hyperbranched structure by click polymerization via the AB2 strategy. Gel permeation chromatography (GPC) results showed that the obtained hyperbranched multicyclic polymer contained 47 cyclic units on average.

We developed a single quantum dot-based fluorescence resonance energy transfer biosensor for antibody-free detection of ten-eleven translocation 1 (TET1). This biosensor can sensitively detect TET1 in a homogeneous manner without the involvement of any specific antibodies, and it can be used for accurate measurement of TET1 activity in human neuroblastoma cells and the screening of TET1 inhibitors.

Ni/ZnO catalysts have been well recognized by industry and academia for exhibiting excellent desulfurization activities. However, the intrinsic reaction mechanism on the Ni active center is still obscure. Herein, we performed periodic density functional theory (DFT) calculations to study thiophene desulfurization and conversion of desulfurization products on the Ni(111) surface and Ni55 cluster, and clarify the size effect of the Ni substrate and the essential role of hydrogen. The thiophene molecule binds more strongly to Ni55 than Ni(111), and proceeds easily along the direct desulfurization pathway without prior hydrogenation on both Ni(111) and Ni55. Ni55 exhibits higher desulfurization activity while Ni(111) performs better in converting the remaining C4H4 species to butadiene and the deposited S atom to H2S. In contrast to the classic S transfer mechanism via H2S, we found that direct S diffusion occurs easily on the Ni substrate and has priority over its further hydrogenation to H2S, indicating that the S diffusion mechanism could play an important role in transferring surface S from Ni to ZnO. The results also show that the C–S bond rupture of thiophene and subsequent S removal from Ni tend to proceed without the assistance of hydrogen, and hydrogen mainly takes part in the hydrogenation of C4H4 species. The present work clearly demonstrates that the rate-determining step for thiophene desulfurization and subsequent alkene formation is the C4H4 hydrogenation rather than the cleavage of C–S bonds, in accordance with the experimental results.

Determining the effect of crystal facets on reaction performance is essential for designing an efficient propane oxidation catalyst. Herein, α-MnO2 nanowires with exposed (110), (211), (310) and (200) facets were proposed, and their crystal facet-dependent reactivity to propane oxidation was investigated. The resultant α-MnO2 nanowires with predominantly exposed (110) facets showed the maximum propane oxidation activity (T90 = 262.1 °C), oxidation rate, and turnover frequency (at 230 °C), and high stability during the oxidation of propane. In situ diffuse reflectance infrared Fourier transform spectroscopy revealed that the oxidation to form carboxylates is the decisive step; therefore, the production of reactive oxygen species is very important. The results from density of states computations revealed that the lowest electron energy was present in the (110) facet, which helps in the generation of reactive oxygen species and the regulation of the surface valence of Mn. The characterization and calculation results indicated that the (110) facets are conducive to forming oxygen vacancies, which allowed the activation and adsorption of O2 and propane, resulting in significantly enhanced propane oxidation activity. Apart from offering new insights about the structure–activity relationship of α-MnO2 with different facets exposed for short-chain volatile oxidation reactions, this study proposes a technique that can be used for improving other manganese-based catalyst oxidation systems.

The development of highly active catalysts for ammonia selective catalytic reduction (NH3-SCR) of NO at low temperatures and the exploration of efficient catalytic active sites are desirable but st...

An integrated reclaimed process of refining slag with calcium-containing wastewater for CO2 mineralization and utilization by using a high-gravity carbonation process was proposed in this study. Th...

The present work aims to develop a novel and sustainable approach to adsorb and recover low-concentration Hg0 in the off-gas downstream a distillation/condensation system in the recycling processes for waste Hg-containing devices. Hg0 adsorption and regeneration efficiencies of raw and HNO3-treated activated carbon fiber cloth (ACFC) were examined. The adsorption experiments were conducted with an initial Hg0 concentration of 260-300 μg/m3 at room temperature. The regeneration of ACFC was done by an electrothermal swing process with 20, 40, and 60 W direct currents. The experimental results showed that the Hg0 adsorption efficiency of raw ACFC increased to approximately 90% after the 60 W electrothermal regeneration. After HNO3 treatment, the content of oxygen functional groups on HNO3-treated ACFC increased, which enhanced the Hg0 adsorption performance and resulted in over 90% adsorption efficiency for the samples before and after electrothermal regeneration. Importantly, both raw and HNO3-treated ACFCs retained the high adsorption efficiency after nine cycles of adsorption/regeneration, indicating that both raw and HNO3-treated ACFCs were effective and renewable adsorbents for low-concentration Hg0 adsorption and recovery. A Hg adsorption/regeneration mechanism was proposed to explain the increasing adsorption efficiency after electrothermal regeneration and the great adsorption efficiency of HNO3-treated ACFC.

The development of controlled/“living” polymerization greatly stimulated the prosperity of the fabrication and application of block copolymer nano-objects. Controlled/“living” polymerization was later extended to the scope of polymerization-induced self-assembly (PISA), in which a linear increase of the solvophobic blocks resulted in systemic variation of the packing parameter and almost ergodic morphology transitions. PISA combines polymerization and self-assembly in a much concentrated solution, which has been demonstrated to be a powerful strategy for fabricating block copolymer nano-objects. Various controlled/“living” polymerization techniques, such as reversible addition–fragmentation chain transfer (RAFT) polymerization, nitroxide-mediated polymerization (NMP), atom transfer radical polymerization (ATRP), “living” anionic polymerization, and ring-opening metathesis polymerization (ROMP), have been used in PISA to date. In this review, we summarize the developments of polymerization techniques in PISA, which complementarily enlarge the scope of PISA to a broad range of reaction conditions and monomer families.

Developing efficient and durable electrocatalysts with uniform sizes for the hydrogen evolution reaction (HER) in the entire pH range and seawater is critical for scalable and sustainable hydrogen production. Herein, we report a supramolecular starch-assisted confinement–assembly–pyrolysis (SCAP) strategy for the synthesis of ultrasmall Rh2P nanoparticles with high dispersion and low loading anchored on N,P-doped porous carbon (NPC). The Rh2P/NPC composite exhibits an unprecedented HER activity with small overpotentials at 10 mA cm−2 (40 mV in 0.5 M H2SO4 and 17 mV in 1 M KOH), as well as superior stability in both acidic and alkaline media. In addition, the Rh2P/NPC catalyst also exhibits an excellent HER performance in the entire pH range. Especially, the Rh2P/NPC catalyst shows an electrocatalytic HER activity superior to that of a 20% Pt/C catalyst in natural seawater, especially under large current densities. It only needs 160, 341 and 411 mV versus RHE to achieve current densities of 10, 100, and 300 mA cm−2, respectively. To the best of our knowledge, this Rh2P/NPC material is the best electrocatalyst reported thus far for seawater electrolysis. Moreover, the Rh2P/NPC catalyst also shows good stability over a wide range of current densities. All these results indicate that the Rh2P/NPC catalyst can be used as a robust catalyst for hydrogen production via direct seawater electrolysis. In situ X-ray absorption spectra revealed the strong interaction between the Rh–P site and H2O during the HER catalytic process in 1 M KOH, revealing the positive role of the Rh–P site in the HER. Theoretical calculations demonstrate that the strong synergistic effects between Rh2P nanoparticles and NPC modify the electronic structure to accelerate the HER kinetics. More interestingly, the SCAP strategy not only yields a robust and pH-universal HER catalyst, but also enables a general, green, and gram-scale synthesis of other metal phosphides.

Commonly observed competitive substrate inhibition in cometabolism of organic contaminants is used as rate- and reducing-power-determining factors to develop a kinetic model of the competitive cometabolism. Analogous to the well-known theory of Leudeking-Piret kinetics where the product formation demands reducing power, cometabolism is modeled as a reducing power demanding process that also competes with microbial growth for the available reducing power from the degradation of energy-yielding primary substrate. The model further incorporates other growth-associated phenomena such as substrate inhibition and multiple growth/nongrowth substrate interactions that may occur during cometabolic transformation processes. The kinetic model is used successfully to predict a variety of degradation patterns of growth/nongrowth substrates, displayed by microbial cultures when exposed to different concentration ratios of growth to nongrowth substrate: a complete degradation of nongrowth substrates that coincides with the simultaneous depletion of a growth substrate and, in some other cases, an incomplete degradation of a nongrowth substrate following the complete depletion of a growth substrate. These distinct patterns of substrate degradation are attributed to intrinsic specificities of enzymes for cometabolism and lack of reducing power available from the growth substrate degradation. The efficacy of cometabolic capabilities of actively growing microbial cultures and pre-cultured resting cells is discussed in terms of reducing power available in such systems.

Recording ion fluctuations surrounding biological cells with a nanoelectronic device offers seamless integration of nanotechnology into living organisms and is essential for understanding cellular activities. The concentration of potassium ion in the extracellular fluid (

Somatic mutation in the KCNJ5 gene is a common driver of autonomous aldosterone overproduction in aldosterone-producing adenomas (APA). KCNJ5 mutations contribute to a loss of potassium selectivity, and an inward Na+ current could be detected in cells transfected with mutated KCNJ5. Among 223 unilateral primary aldosteronism (uPA) individuals with a KCNJ5 mutation, we identified 6 adenomas with a KCNJ5 p.Gly387Arg (G387R) mutation, previously unreported in uPA patients. The six uPA patients harboring mutant KCNJ5-G387R were older, had a longer hypertensive history, and had milder elevated preoperative plasma aldosterone levels than those APA patients with more frequently detected KCNJ5 mutations. CYP11B2 immunohistochemical staining was only positive in three adenomas, while the other three had co-existing multiple aldosterone-producing micronodules. The bioinformatics analysis predicted that function of the KCNJ5-G387R mutant channel could be pathological. However, the electrophysiological experiment demonstrated that transfected G387R mutant cells did not have an aberrantly stimulated ion current, with lower CYP11B2 synthesis and aldosterone production, when compared to that of the more frequently detected mutant KCNJ5-L168R transfected cells. In conclusion, mutant KCNJ5-G387R is not a functional KCNJ5 mutation in unilateral PA. Compared with other KCNJ5 mutations, the observed mildly elevated aldosterone expression actually hindered the clinical identification of clinical unilateral PA. The KCNJ5-G387R mutation needs to be distinguished from functional KCNJ5 mutations during genomic analysis in APA evaluation because of its functional silence.

We previously demonstrated the antioxidant activity of Coeloglossum viride var. bracteatum extract (CE) in rat cortical neurons and in mice with chemically induced cognitive impairment. In this work, we established a staurosporine (STS)-induced toxicity model to decipher the neuroprotective mechanisms of CE. We found that CE protected cell viability and neurite integrity in STS-induced toxicity by restoring the levels of FGF2 and its associated PI3K/Akt signaling axis. LY294002, a pan-inhibitor of PI3K, antagonized the activity of CE, although its-mediated restoration of FGF2 was unaffected. In addition, CE restored levels of Bcl-2/Caspase-3, PKCα/CaM pathway, and Dnmt3a and Dnmt3b, two methyltransferases that contribute to de novo DNA methylation. The Dnmts inhibitor 5-azacytidine impaired CE-mediated restoration of Dnmt3 or CaM, as well as the transition of DNA methylation status on the Dnmt3 promoter. These results reveal potential mechanisms that could facilitate the study and application of CE as a neuroprotective agent., CE; Dnmt3a; Dnmt3b; FGF2; PI3K/Akt; Staurosporine

Due to the low efficiency of single-component nano materials, there are more and more studies on high-efficiency composites. As zero dimensional (0D) non-metallic semiconductor material, the emergence of graphene quantum dots (GQDs) overcomes the shortcomings of traditional photocatalysts (rapid rate of electron-hole recombination and narrow range of optical response). Their uniqueness is that they can combine the advantages of quantum dots (rich functional groups at edge) and sp2 carbon materials (large specific surface area). The inherent inert carbon stabilizes chemical and physical properties, and brings new breakthroughs to the development of benchmark photocatalysts. The photocatalytic efficiency of GQDs composite with semiconductor materials (SCs) can be improved by the following three points: (1) accelerating charge transfer, (2) extending light absorption range, (3) increasing active sites. The methods of preparation (bottom-up and top-down), types of heterojunctions, mechanisms of photocatalysis, and applications of GQDs/SCs (wastewater treatment, energy storage, gas sensing, UV detection, antibiosis and biomedicine) are comprehensively discussed. And it is hoped that this review can provide some guidance for the future research on of GQDs/SCs on photocatalysis.

Biochar is a carbon-rich material prepared from the pyrolysis of biomass under various conditions. Recently, biochar drew great attention due to its promising potential in climate change mitigation, soil amendment, and environmental control. Obviously, biochar can be a beneficial soil amendment in several ways including preventing nutrients loss due to leaching, increasing N and P mineralization, and enabling the microbial mediation of N2O and CO2 emissions. However, there are also conflicting reports on biochar effects, such as water logging and weathering induced change of surface properties that ultimately affects microbial growth and soil fertility. Despite the voluminous reports on soil and biochar properties, few studies have systematically addressed the effects of biochar on the sequestration of carbon, nitrogen, and phosphorus in soils. Information on microbially-mediated transformation of carbon (C), nitrogen (N), and phosphorus (P) species in the soil environment remains relatively uncertain. A systematic documentation of how biochar influences the fate and transport of carbon, phosphorus, and nitrogen in soil is crucial to promoting biochar applications toward environmental sustainability. This report first provides an overview on the adsorption of carbon, phosphorus, and nitrogen species on biochar, particularly in soil systems. Then, the biochar-mediated transformation of organic species, and the transport of carbon, nitrogen, and phosphorus in soil systems are discussed. This review also reports on the weathering process of biochar and implications in the soil environment. Lastly, the current knowledge gaps and priority research directions for the biochar-amended systems in the future are assessed. This review focuses on literatures published in the past decade (2009–2021) on the adsorption, degradation, transport, weathering, and transformation of C, N, and P species in soil systems with respect to biochar applications.

A new type of biological folded non-aerated filter (BFNAF) was found to be superior and feasible for the treatment of NH4+-N wastewater. It was constructed with the folded structure suitable for the nylon biomass carrier. The advantages of the BFNAF included low energy consumption, long reaction path, large biofilm surface area and non-clogging compared to the traditional biological aerated filter. In this study, the effects of hydraulic retention time (HRT), and the influent NH4+-N concentration on the performance of BFNAF were investigated and optimized by the response surface methodology. Under the optimal operating condition (HRT, 10 h; NH4+-N concentration, 52 mg/L), the removal efficiency and removal rate were 94.62 ± 0.63% and 0.106 kg-NH4+ m−3 day−1, respectively. The results showed that the BFNAF reactor could remove NH4+-N from wastewater and realized the nitrification process effectively under natural ventilation conditions.

This study investigated a series of ferrocenyltelluroether based cuprous halide clusters as effective single-molecule metallaphotocatalysts (SMP) in white light-driven C[sbnd]H arylation at room temperature and air. A systematic mechanistic study reveals that Cu(I) cluster can be irradiated by visible light to promote proton-coupled electron transfer (PCET), during which the electron from Cu(I)* leaves together with the proton from benzothiazole C[sbnd]H, leading to the formation of benzothiazolate-coordinated Cu(II) intermediate and aryl radical. Subsequently, the electron transfer (ET) from the ferrocene unit to the Cu(II) center releases the reactive benzothiazolate to form the target product with aryl radical. The advantages of these copper(I) halide clusters as SMP include high photocatalytic efficiency, structure adjustability, mild reaction conditions and good functional group tolerance., This work is funded by the National Natural Science Foundation of China (NSFC Project Nos. 21671101, 21871137, 21875104, and 51673095), Department of Ecological Environment of Jiangsu Province (Project No. 2018011), and Natural Science Fund for Distinguished Young Scholars of Jiangsu Province (BK20180037) and Natural Science Foundation of Jiangsu Province (BK20181374).

For electrocatalysts for the hydrogen evolution reaction (HER), encapsulating transition metal phosphides (TMPs) into nitrogen-doped carbon materials has been known as an effective strategy to elevate the activity and stability. Yet still, it remains unclear how the TMPs work synergistically with the N-doped support, and which N configuration (pyridinic N, pyrrolic N, or graphitic N) contributes predominantly to the synergy. Here we present a HER electrocatalyst (denoted as MoP@NCHSs) comprising MoP nanoparticles encapsulated in N-doped carbon hollow spheres, which displays excellent activity and stability for HER in alkaline media. Results of experimental investigations and theoretical calculations indicate that the synergy between MoP and the pyridinic N can most effectively promote the HER in alkaline media.

A novel modified polyoxometalate, {PMo12O40[Cu(2,2′-bpy)]}[Cu(2,2′-bpy)(en)(H2O)]2 [2,2′-bpy is 2,2′-bipyridyl (C10H8N2) and en is ethylenediamine (C2H8N2)], has been synthesized hydrothermally and structurally characterized by elemental analysis, TG, IR, XPS and single-crystal X-ray diffraction. The structural analysis reveals that the compound contains the reduced Keggin polyanion [PMo12O40]6− as the parent unit, which is monocapped by [Cu(2,2′-bpy)]2+ fragments via four bridging O atoms on an {Mo4O4} pit and bi-supported by two [Cu(2,2′-bpy)(en)(H2O)]2+ coordination cations simultaneously. There exist strong intramolecular π–π stacking between the capping and supporting units, which play a stabilizing role during the crystallization of the compound. Adjacent POM clusters are further aggregated to form a three-dimensional supramolecular network through noncovalent forces, hydrogen bonding and π–π stacking interactions. In addition, the photocatalytic properties were investigated in detail, and the results indicated that the compound can be used as a photocatalyst towards the decomposition of the organic pollutant methylene blue (MB).

Atomically dispersed metal-N-C structures are efficient active sites for catalyzing benzene oxidation reaction (BOR). However, the roles of N and C atoms are still unclear. We report a polymerization-regulated pyrolysis strategy for synthesizing single-atom Fe-based catalysts, and present a systematic study on the coordination effect of Fe-NxCy catalytic sites in BOR. The special coordination environment of single-atom Fe sites brings a surprising discovery: Fe atoms anchored by four-coordinating N atoms exhibit the highest BOR performance with benzene conversion of 78.4% and phenol selectivity of 100%. Upon replacing coordinated N atoms by one or two C atoms, the BOR activities decrease gradually. Theoretical calculations demonstrate the coordination pattern influences not only the structure and electronic features, but also the catalytic reaction pathway and the formation of key oxidative species. The increase of Fe-N coordination number facilitates the generation and activation of the crucial intermediate O=Fe=O species, thereby enhancing the BOR activity., Atomically dispersed metal-N-C are efficient active site for benzene oxidation but the roles of N and C atoms are still unclear. Here the authors report a highly-active single-atom Fe-based benzene oxidation catalyst and provide deep insights into the structure-activity relationship at atomic level.

Anammox is a distinctive bacterium that is extremely sensitive to and inhibited by organic matter. This weakness becomes a limiting factor for the application of anammox to treat wastewater especially that the underlying mechanisms in the inhibition of phenol remain unclear. In this study, phenol was chosen to determine the possible factors leading to the inhibition of anammox through community variation and molecular simulations. Results of the short-time batch experiment showed that 400 mg L−1 or 1000 mg L−1 of phenol immediately inhibited the anammox activity. Profiles from 16S rRNA sequences showed that the community structures remained unchanged during the first four hours. Molecular simulation between phenol and the key enzyme hydrazine synthase (HZS) showed that phenol combined with HZS and even had the ability to competitively bind with HZSα-haem αI and HZSγ-haem γI sites.

A new strategy combing quantitative reactions and reversible-covalent chemistry is proposed for sequential synthesis of a series of sequence-controlled polymers with different sequences. Using a Michael addition reaction between acrylate and thiol, an aminolysis reaction of five-membered cyclic dithiocarbonate and a thiol substitution reaction of bromomaleimide and thiol, AB-, AB'C- and AB'CD-sequenced molecules are synthesized via AB, AB'C and AB'CD sequential monomer additions, respectively. These three molecules all have furan-protected maleimido group at one end, and the other end of AB-, AB'C- and AB'CD-sequenced molecules is amine, thiol and anthracene groups, respectively. Due to the fact that the furan-protected maleimido group can be efficiently transformed to maleimide group at high temperature via retro Diels-Alder reaction, AB-, AB'C- and AB'CD-sequenced molecules polymerize into sequence-controlled polymers with corresponding sequences at 120 °C. Through this strategy, the synthesis of molecular modules does not require separation and purification, and sequence-controlled polymers with specific sequence can be synthesized in a one-pot process via adding different monomers and adjusting reaction condition.

Excess sludge contains a large amount of organic matter, most of which is present in the form of bacteria and extracellular polymeric substances. In this study, a photosynthetic bioelectrochemical system (BES) combined with ultrasonic treatment (UT) was investigated to mineralize sludge. The sludge was disintegrated by the UT, and the supernatant separated from the treated sludge was further degraded through a bioelectrochemical system containing photosynthetic bacteria (PSB-BES). The UT efficiency was enhanced by supernatant separation. The PSB-BES method effectively improved the degradation of the soluble chemical oxygen demand (SCOD) from the supernatant. The SCOD and protein removal were increased 1.4 and 1.5 times, respectively, compared to BES without PSB. In addition, the effects of several key operating factors including illumination, voltage, and temperature were systematically investigated. This study provides a basis for further development of sludge mineralization processes. PRACTITIONER POINTS: The sludge was disintegrated by the ultrasound treatment. The supernatant separated from treated sludge was further degraded by a bioelectrochemical system combined with photosynthetic bacteria. The ultrasonic treatment efficiency was enhanced by supernatant separation. The PSB-BES method effectively improved the soluble chemical oxygen demand (SCOD) degradation from the supernatant. The effects of several key operating factors including light (dark-photo), voltage, and temperature were systematically investigated.

The exploration of low-cost, stable, and highly active noble-metal-free electrocatalyst for hydrogen evolution reaction (HER) in a wide pH range is crucial but still challenging task for renewable energy techniques. MoS2-based materials have been considered as a promising electrocatalyst for HER. However, corresponding studies have been hampered by the lack of effective routes to fully utilize the large number of inert basal plane for catalyzing HER, especially under alkaline media. Herein, a novel ammonia ions-guided-nitrogenization-phosphorization strategy is developed to prepare N and P co-doped MoS2 with active basal plane for efficient catalyzing HER with a quite low overpotential of 116 and 78 mV in 0.5 M H2SO4 and 1.0 M KOH to achieve a current density of 10 mA cm−2, respectively. Experimental studies and theoretical calculations confirm Mo-N-P sites in the basal plane of MoS2 can not only accelerate HER kinetics, but also result in energetic favorability and structure stability. Furthermore, outstanding performances are also obtained under both sea and river water, vastly broadening the application prospects.

Stimuli-responsive polymeric vesicles have attracted great attention in drug delivery due to their intrinsic hollow structures and “on demand” release of drugs upon environmental stimuli. The drug-release kinetics from polymeric vesicles, which is usually dependent on the stimuli-responsive behaviors of the polymeric vesicle, has great impacts on the therapeutic efficacy. Over the past decade, polymerization-induced self-assembly (PISA) has been demonstrated to be a powerful strategy to prepare the polymeric vesicles. However, fabrication of stimuli-responsive vesicles with adjustable drug release kinetics via PISA has been rarely reported, which may be due to the poor selectivity of functional membrane-forming polymers in the PISA system. Herein, a series of vesicles with different pH-responsive behaviors were fabricated via RAFT dispersion copolymerization of (diisopropylamino)ethyl methacrylate (DIPEMA) and benzyl methacrylate (BzMA). Both the content of DIPEMA units in hydrophobic P(DIPEMA-co-BzMA) bl...

The electrochemical reduction of CO2 could play an important role in addressing climate-change issues and global energy demands as part of a carbon-neutral energy cycle. Single-atom catalysts can display outstanding electrocatalytic performance; however, given their single-site nature they are usually only amenable to reactions that involve single molecules. For processes that involve multiple molecules, improved catalytic properties could be achieved through the development of atomically dispersed catalysts with higher complexities. Here we report a catalyst that features two adjacent copper atoms, which we call an ‘atom-pair catalyst’, that work together to carry out the critical bimolecular step in CO2 reduction. The atom-pair catalyst features stable Cu10–Cu1x+ pair structures, with Cu1x+ adsorbing H2O and the neighbouring Cu10 adsorbing CO2, which thereby promotes CO2 activation. This results in a Faradaic efficiency for CO generation above 92%, with the competing hydrogen evolution reaction almost completely suppressed. Experimental characterization and density functional theory revealed that the adsorption configuration reduces the activation energy, which generates high selectivity, activity and stability under relatively low potentials. Anchored single-atom catalysts have recently been shown to be very active for various processes, however, a catalyst that features two adjacent copper atoms—which we call an atom-pair catalyst—is now reported. The Cu10–Cu1x+ pair structures work together to carry out the critical bimolecular step in CO2 reduction.

Rational design of alternative, cost-effective and highly active electrocatalysts for the hydrogen evolution reaction (HER) in alkaline and neutral media is greatly desirable and challenging. In this work, we developed a simple but effective manganese-metal-heteroatom doping strategy to realize the simultaneous modulations of the active site number, water dissociation, and hydrogen adsorption free energy in pyrite NiS2 hierarchical nanosheets to significantly boost alkaline and neutral HER catalysis. Specifically, the incorporation of Mn heteroatoms into the NiS2 system, as revealed by HRTEM, XPS, XANES spectra and theoretical studies, not only induce lattice distortions and defects for increasing the exposure of active sites, but also effectively optimize the electronic structure configuration of Ni sites, leading to optimal hydrogen adsorption free energy. In addition, the doped Mn heteroatom itself can act as a water-activated site to lower the energy barrier of water dissociation. As a result, the synergistic regulation of active sites and HER kinetics brings nearly 9-fold enhancement of alkaline HER activity for Mn-doped NiS2/Ni foam (NF) with a quite low overpotential of 71 mV to reach 10 mA cm−2 in 1 M KOH, which is among the most active HER electrocatalysts reported to date. Despite few reports about the effective neutral HER on transition-metal sulfides so far, a small overpotential of 84 mV at 10 mA cm−2 can be achieved in 1 M phosphate-buffered saline (PBS, pH 7). Furthermore, the Mn-doped NiS2/NF electrode also exhibits efficient and stable HER performances in near-neutral real seawater and has no obvious catalytic degradation after various extreme bending tests, verifying its high flexibility and robustness under severe conditions, which vastly broadens its application prospects.

Highlights • Y90 radioembolization has shown feasibility for downstaging patients for resection. • Functional liver reserve is a choice pre-surgery/postradioembolization measurement. • Tc-99 m Sulfur Colloid SPECT-CT can assess functional liver reserve before surgery., Introduction Quantitative assessment is an essential tool in determining the proportion of liver to be reserved before lobectomy. Technetium-99 m sulfur colloid single-photon emission computed tomography (Tc-99 m SC SPECT-CT) can help in the quantitative assessment of functioning liver tissues and percentage of liver reserve before segmentectomy and lobectomy Matesan et al. (2017), Bowen et al. (2016) and Lam et al. (2013). Presentation of case A 64-year-old man with alcoholic cirrhosis was admitted to our hospital with a 15 × 10 x 13 cm bilobar HCC. Y90 radioembolization was utilized to downstage the liver tumor. On follow-up CT scan of the liver after radiotherapy, the HCC was much reduced to 6.5 cm in size but still viable with elevated alpha fetoprotein ([AFP] from 225 to 381 to 959 ng/mL). Resection was considered. Constitutional indocyanine green retention at 15 min (ICG-R-15) was 22%. We introduced the Tc-99 m SC SPECT-CT scan in order to assess the percentage liver function of each lobe. It showed minimal uptake in the remaining functioning right lobe with a hypertrophic left lobe to whole liver uptake ratio of 87.1%. This finding gave us confidence to perform right hepatectomy. Discussion We used Tc-99 m SC SPECT-CT to estimate the normal functional liver reserve after Y90 radioembolization of a hepatocellular carcinoma (HCC). To our understanding, it is the first case report using Tc-99 m SC to predict the percentage of functional liver reserve after yttrium-90 (Y90) radioembolization. Conclusion Tc-99 m SC SPECT-CT is a novel helper used to assess the differential liver function after Y90 radioembolization of HCC and before segmentectomy and lobectomy of the liver.

Xiao Qing Long Tang (literally “Minor blue dragon decoction” in Chinese), a traditional Chinese formula, is prescribed to treat respiratory diseases. However, only few studies have been reported on its anti-inflammatory mechanisms. In this study, we investigated the inhibitory effects of Xiao Qing Long Tang essential oil on inflammatory mediators and explored the mechanisms of action of XQEO in the lipopolysaccharide (LPS)-stimulated RAW264.7 cells. XQEO was prepared via steam distillation and characterized by GC-MS analysis. MTT and Griess assays were used to measure cell viability and NO production, respectively. The mRNA expression and the production of LPS-induced pro-inflammatory cytokines (IL-1β, IL-6, TNF-α, and IL-10) and chemokines (MCP-1, Rantes, and MIP-1α) were determined by real-time PCR and enzyme-linked immunosorbent assay, respectively. Furthermore, we determined the protein levels of the components of NF-κB, AP-1 and IRF3 signalling by Western blotting. Immunofluorescence assay was used to estimate the nuclear translocation of NF-κB, AP-1 and IRF3. The results showed that XQEO inhibited the secretion of NO and PGE2 and down-regulated the mRNA and protein levels of iNOS and COX-2. We also found that XQEO suppressed the LPS-induced overproduction of pro-inflammatory mediators. Moreover, XQEO inhibited the phosphorylation of NF-κB/p65, AP-1/c-Jun, and IRF3 by suppressing their upstream kinases, such as MAPKs, TBK1, Akt, IKKα/β, and IκB, reducing the LPS-induced NF-κB, AP-1 and IRF3 translocation to the nucleus. These findings suggest that XQEO effectively suppresses the production of pro-inflammatory mediators possibly through the inhibition of NF-κB, AP-1, and IRF3 signalling in the LPS-stimulated RAW264.7 cells.

Development of nonprecious, efficient, and stable electrocatalysts for overall water splitting under mild conditions is crucial but still a huge challenge for the renewable energy techniques. Herein, a facile hydrothermal and then selenization strategy is proposed to synthesize hierarchical nickel sulfoselenide (NiS2(1−x)Se2x) hollow/porous spheres with controllable composition for electrocatalytic water splitting in neutral media. By regulating the degree of selenization, the Se/S atomic ratio in the nickel sulfoselenides can be controlled to realize the tunable electronic structure of nickel to boost its intrinsic activity. Benefiting from their unique structural features and the anion doping effect, nickel sulfoselenides, especially with the chemical composition Ni(S0.5Se0.5)2, are discovered to exhibit high activity and stability toward both hydrogen and oxygen evolution reactions under neutral conditions. When using Ni(S0.5Se0.5)2 as a bifunctional electrode as both the anode and cathode in a neutral electrolyte, it demonstrates a durable activity for overall water splitting to drive 10 mA cm−2 at a cell voltage of merely 1.87 V, outperforming the noble metal-based Pt/C and IrO2 couple. This study not only offers a new type of promising earth-abundant electrocatalyst towards water electrolysis under benign conditions, but also highlights that anion doping engineering or composition control can be an elegant strategy to improve the electrochemical catalytic performance.

Multicyclic polystyrene (PS) with hyperbranched structure was constructed in an efficient way. First, a seesaw-type PS was synthesized via atom transfer radical polymerization (ATRP) using a Y-shaped ATRP initiator containing one hydroxyl at center and bromine at each end. After azidation, the anthryl and hydroxyl groups were introduced to the ends of the polymer chain by click reaction with a trifunctional molecule bearing alkynyl, hydroxyl, and anthryl groups (alkynyl-OH-ant). By irradiation with 365 nm UV light in a highly dilute condition, cyclic polymer with three hydroxyl groups (c-PS-(OH)3) can be obtained; then it was converted to a cyclic polymer containing three azides (c-PS-(N3)3) by bromination of the hydroxyl groups and azidation. This “A3” cyclic macromonomer was then used to construct hyperbranched multicyclic polymers via self-accelerating click reaction with sym-dibenzo-1,5-cyclooctadiene-3,7-diyne (DBA). The properties of obtained polymer were characterized by NMR, FT-IR, MALDI-TOF MS, a...

Azo dyes and their decolorized products are toxic and persistent to biodegradation, but must be properly removed before dye wastewater being discharged to a water body. In this study, a bioelectrochemical system (BES) combined with a membrane biofilm reactor (MBfR) has been investigated for removing azo dye and its reduction products. Acid orange 7 (AO7) as a model azo dye was efficiently removed (96.5 ± 0.6%) in the BES cathode, and its reduction product - sulfanilic acid was further degraded by the MBfR (64.7 ± 2.7%) at a lumen pressure of 30 psi. Loop operation eliminated the anode substrate addition by taking advantages of residue substrate from the MBfR. The energy consumption by this integrated system was estimated between 1.31 ± 0.01 and 2.33 ± 0.05 kWh kg AO7–1. It was demonstrated by cyclic voltammetry that decolorization products of the AO7 contained in the MBfR effluent could serve as redox mediators for enhancing current generation in the BES.

Residual hydrated cement powder (HCP) produced from recovering recycled concrete is usually restricted from being directly reused in concrete due to its high water absorption and porous str...

The accumulation of heavy metals in paddy rice severely impacts the health of consumers and plants. In this study, a systematic approach to source-sink apportionment of copper in paddy fields was developed by considering all bioenvironmental interfaces. Experimental data from two experimental fields (namely Field A and Field B) in the first harvest period was collected. Then, mass-balance-based models with dynamic critical loads were established to evaluate the year of excess for copper. The results indicated that irrigation water contributed the highest portion (96.2–98.8%) of total copper inputs. Under the business-as-usual scenario, the soil copper concentration of Field A and Field B might exceed the Taiwanese national standard within 66 and 24 years, respectively. In addition, alternate wet-dry irrigation was found to be one of the total solutions to reducing copper accumulation in soils by 17–48%. It could also provide a significant reduction of water usage in paddy fields by ~25%, thereby increasing the resilience to extreme climate change events. Lastly, based on the field observations, three improvement strategies on sustaining soil quality towards better agricultural environment were proposed. The connection of copper accumulation in soils with dietary and ecological risks was also briefly illustrated.

Background The etiology between homocysteine and polycystic ovary syndrome (PCOS) is unclear. In humans, the level of homocysteine is mainly affected by two enzymes: methylene tetrahydrofolate reductase (MTHFR) and methionine synthase reductase (MTRR). While the activity of these two enzymes is mainly affected by three missense mutations, namely C677T (MTHFR), A1298C (MTHFR), and A66G (MTRR). This study aims to examine the association between the three missense mutations and PCOS and investigate whether the three missense mutations exerted their effect on PCOS by affecting the homocysteine level. Methods A case-control study was designed, comprising 150 people with PCOS and 300 controls. Logistic regression analysis was used to assess the association between the three missense mutations and PCOS. Linear regression analysis was used to assess the association between the three missense mutations and the homocysteine level. Mediation analysis was used to investigate whether the three missense mutations exerted their effect on PCOS by affecting the homocysteine level. Results Following adjustments and multiple rounds of testing, MTHFR A1298C was found to be significantly associated with PCOS in a dose-dependent manner (compared to AA, OR = 2.142 for AC & OR = 3.755 for CC; P MTRR A66G was nominally associated with PCOS. Mutations in MTHFR A1298C and MTRR A66G were significantly associated with the homocysteine level. Mediation analysis suggested the effect of MTHFR A1298C on PCOS was mediated by homocysteine. Conclusions MTHFR A1298C and MTRR A66G were associated with PCOS, and MTHFR A1298C might affect the risk of PCOS by influencing the homocysteine level.

Coptis chinensis Franch, a perennial herb, is mainly distributed in southeastern China. The rhizome of C. chinensis has been used as a traditional medicine for more than 2000 years in China and many other Asian countries. The pharmacological activities of C. chinensis have been validated by research. Here, we present a de novo high-quality genome of C. chinensis with a chromosome-level genome of ~958.20 Mb, a contig N50 of 1.58 Mb, and a scaffold N50 of 4.53 Mb. We found that the relatively large genome size of C. chinensis was caused by the amplification of long terminal repeat (LTR) retrotransposons. In addition, a whole-genome duplication event in ancestral Ranunculales was discovered. Comparative genomic analysis revealed that the tyrosine decarboxylase (TYDC) and (S)-norcoclaurine synthase (NCS) genes were expanded and that the aspartate aminotransferase gene (ASP5) was positively selected in the berberine metabolic pathway. Expression level and HPLC analyses showed that the berberine content was highest in the roots of C. chinensis in the third and fourth years. The chromosome-level reference genome of C. chinensis provides important genomic data for molecular-assisted breeding and active ingredient biosynthesis.

Recently, persulfate-based advanced oxidation processes (persulfate-AOPs) are booming rapidly due to their promising potential in treating refractory contaminants. As a type of popular two-dimensional material, layered double hydroxides (LDHs) are widely used in energy conversion, medicine, environment remediation and other fields for the advantages of high specific surface area (SSA), good tunability, biocompatibility and facile fabrication. These excellent physicochemical characteristics may enable LDH-based materials to be promising catalysts in persulfate-AOPs. In this work, we make a summary of LDHs and their composites in persulfate-AOPs from different aspects. Firstly, we introduce different structure and important properties of LDH-based materials briefly. Secondly, various LDH-based materials are classified according to the type of foreign materials (metal or carbonaceous materials, mainly). Latterly, we discuss the mechanisms of persulfate activation (including radical pathway and nonradical pathway) by these catalysts in detail, which involve (i) bimetallic synergism for radical generation, (ii) the role of carbonaceous materials in radical generation, (iii) singlet oxygen (1O2) production and several special nonradical mechanisms. In addition, the catalytic performance of LDH-based catalysts for contaminants are also summarized. Finally, challenges and future prospects of LDH-based composites in environmental remediation are proposed. We expect this review could bring new insights for the development of LDH-based catalyst and exploration of reaction mechanism.