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Post-GOE deep-water Fe-Si precipitates associated with volcanogenic massive sulfide deposits are an important feature of the Proterozoic rock record. Although it is clear that these enigmatic deposits formed in oxygen-deficient and hydrothermally influenced deep-water settings, the oxidation mechanism(s) resulting in their precipitation remain(s) unclear. Whilst existing genetic models typically couple direct and/or bacterially-mediated iron oxidation with abiotic silica precipitation, low temperature diffuse hydrothermal fluids offer a potential mechanistic alternative to explain the observed layering. Herein, via combination of petrographic observations with elemental and isotopic data (Fe, Si, and O), we explore the genesis of the primary mineral phases present within recent Fe-Si precipitates obtained from the Southwest Indian Ridge. Formation of ferrihydrite and opal-A in these precipitates provides insight into the genesis of widely invoked precursor minerals to post-GOE deep-water Fe-Si precipitates. Specifically, we find that the mineralogical layers that typify these Fe-Si precipitates may have originated via biologically mediated ferrihydrite precipitation and abiotic precipitation of opal-A from oversaturated fluids during diffuse flow. By analogy, we propose that diffuse hydrothermal fluid flow played an important role in the formation of post-GOE deep-water Fe-Si precipitates.

Solar photocatalysis is the key to resolve many environmental challenges but is usually hard to achieve over a metal oxide semiconductor. Therefore, assembling π-conjugated molecules onto semiconductors becomes an efficient approach to solar conversion via ligand-to-metal charge transfer. Here, a rational design of ligands for titanium dioxide (TiO2) is presented to produce robust visible light photocatalysts. Three hydroxynaphthoic acids (HNAs) were selected as ligands by extending an extra benzene ring of salicylic acid (SA) at 3,4 or 4,5 or 5,6 positions. These ligands could regulate the performance of TiO2 in which 2-hydroxy-1-naphthoic acid (2H1NA) endows the best outcome. In detail, blue light-powered cooperative photocatalysis of 2H1NA-TiO2 with 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO, 5 mol%) inaugurates the expeditious formation of imines by oxidation of amines with atmospheric oxygen (O2). Interestingly, the increase of the O2 pressure from 1 atm to 0.4 MPa promoted the selective oxidation of benzylamine but thereafter declined with a further boost to 0.6 MPa. Notably, an electron transfer between the oxidatively quenched 2H1NA-TiO2 and TEMPO is established, offering a new pathway for environmental applications. This work presents a strategy in designing cutting-edge visible light photocatalysts via altering semiconductors with surface ligands.

Ultrahigh charge separation was observed in Bi4O5I2/Bi5O7I two-dimensional (2D)/one-dimensional (1D) hierarchical structures (HSs) constructed by selective growth of 2D monocrystalline Bi4O5I2 nanoplates on the electron-accumulating (100) facet of 1D monocrystalline Bi5O7I nanobelts. In addition to the presence of type-II heterojunction between Bi4O5I2 and Bi5O7I elementary entities in 2D/1D HSs, the type-II (100)/(001) surface heterojunction in Bi5O7I nanobelt substrates was also confirmed by means of density functional theory (DFT) calculations and selective photoreduction/oxidation deposition experiments. The synergistic effect of two kinds of heterojunctions in Bi4O5I2/Bi5O7I 2D/1D HSs endowed them with ultrahigh charge carrier separation and transfer characteristics. In contrast with the control sample (BB40-C) constructed by growing Bi4O5I2 nanoplates on whole four sides of Bi5O7I nanobelts, Bi4O5I2/Bi5O7I 2D/1D HSs demonstrated significantly enhanced charge transfer between Bi5O7I nanobelt substrates and Bi4O5I2 nanoplates, owing to respective electron and hole accumulations on (100) and (001) facets of Bi5O7I substrates caused by (100)/(001) surface heterojunction. The enhanced separation behavior was successfully verified by steady/transient-state photoluminescence, electrochemical techniques, and photocatalytic degradation experiments. Based on the above effective charge separation of Bi4O5I2/Bi5O7I 2D/1D HSs as well as the routine advantages for 2D/1D HSs, such as the excellent charge transport in monocrystalline elementary entities, much higher specific surface area, and enhanced light absorption by multiple reflections, the optimal BB40 HSs demonstrated ultrahigh photocatalytic performance than the control samples, whose apparent rates for Rhodamine B [or tetracycline hydrochloride (TC)] degradation were 7.1 (2.9 for TC), 10.3 (4.7 for TC), and 2.2 (1.7 for TC) times those of pristine Bi5O7I nanobelts, Bi4O5I2 nanoplates, and BB40-C, respectively. It is hoped that this crystal facet selection during the heterostructure construction in this work could provide a new strategy or some enlightenment for the exploration of highly active 2D/1D HSs or other-dimensional heterostructure nanomaterials applied in the fields of photocatalysts, solar cells, sensors, and others.

Attaching π-conjugated molecules onto TiO2 can form surface complexes that could capture visible light. However, to make these TiO2 surface complexes durable, integrating 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) or its analogues as a redox mediator with photocatalysis is the key to constructing selective chemical transformations. Herein, sodium 6,7-dihydroxynaphthalene-2-sulfonate (DHNS) was obtained by extending the π-conjugated system of catechol by adding a benzene ring and a substituent sodium sulfonate (-SO3 - Na+ ). The DHNS-TiO2 showed the best photocatalytic activity towards the blue light-induced selective aerobic oxidation of benzylamine. Compared to TEMPO, 4-amino-2,2,6,6-tetramethylpiperidine-1-oxyl (4-amino-TEMPO) could rise above 70% in conversion of benzylamine over the DHNS-TiO2 photocatalyst. Eventually, a wide range of amines could be selectively oxidized into imines with atmospheric O2 by cooperative photocatalysis of DHNS-TiO2 with 4-amino-TEMPO. Notably, superoxide (O2 •- ) is crucial in coupling the photocatalytic cycle of DHNS-TiO2 and the redox cycle of 4-amino-TEMPO. This work underscores the design of surface ligands for semiconductors and the selection of a redox mediator in visible light photocatalysis for selective chemical transformations.

Selective sorting of semiconducting single-walled carbon nanotubes (SWNTs) of single chirality is critical for constructing electronic nanodevices with high performance. Nevertheless, trade-off bet...

Aflatoxin B1 (AFB1) is one of the most toxic, mutagenic and carcinogenic mycotoxin, widely exists in contaminated food, grains and feedstuff products. In this study, a novel magnetic beads multicolor colorimetric immunoassay (MBMCIA) based on Au@Ag nanorods (Au@Ag NRs) is proposed to visual detect ultralow concentration of AFB1 with high-resolution by the naked-eye. To design the MBMCIA system, AFB1-BSA conjugates were first coated on the surface of magnetic beads (MBs), then alkaline phosphatase (ALP) as a bridge between immunoassay and color reaction was used for catalytic hydrolysis of ascorbic acid-phosphate to generate reductive ascorbic acid. Finally, the yielded ascorbic acid could reduce silver ions to grow a silver coating on the surface of gold nanorods to generate Au@Ag NRs, which leads to the bule-shifted longitudinal absorption peak of Au NRs, accompanying with a series of perceptible color change. Under the optimal conditions, the proposed MBMCIA exhibited good sensitivity and specificity for the detection of AFB1 with the detection limit as low as 5.7 pg/mL. Meanwhile, the MBMCIA was also applied for the analysis of AFB1 in spiked wheat samples, the obtained recoveries range from 99.1% to 104.3% with relative standard deviation (RSD) less than 7.05% were acceptable. The proposed MBMCIA integrates separated, enriched, anti-interference and signal read-out into one, which opens up a new avenue for an on-site visual food safety inspection or environmental monitoring.

Oxidative etching possesses an enriched flexibility and atomic-level accuracy in tailoring the size, morphology, surface structure, and composition of colloidal nanocrystals toward their catalytic ...

A four-component and one-pot synthesis involving N,S-acetalation of aldehydes with cysteine followed by the reaction with second aldehydes for decarboxylative [3 ​+ ​2] cycloaddition with maleimides is developed for stereoselective synthesis of tetrahydropyrrolothiazoles. High synthetic efficiency, using EtOH as solvent and catalyst, and only releasing CO2 and H2O as byproducts make this method favorable in green metrics analysis.

Nb2O5 is a colourless metal oxide that is very promising in areas such as energy storage and optical glasses. These applications depend on the superior redox properties of Nb2O5 compared to those of other metal oxides, which in turn endow it with great potential in semiconductor photocatalysis. Herein, a hierarchical Nb2O5 was synthesized by the L-arginine-assisted hydrothermal method. Thereafter, visible light photocatalysis was bridged over hierarchical Nb2O5 with a common organic dye, namely alizarin red S (ARS), significantly renovating Nb2O5-based photocatalysis from ultraviolet (UV) into the green light region. The surface of hierarchical Nb2O5 was chemically modified with ARS to harvest 520 nm green light and facilitate the oxidation of organic sulfides with aerial O2. The O-atom transfer from O2 into sulfoxides with very high selectivity occurs via an intermediate of superoxide radical anions (O2˙−). Importantly, the electron transfer from activated ARS to sulfides is mediated by an electron transfer mediator, namely (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO), to deter the attack of quenched ARS by reactive oxygen species (ROS). This study represents the first foray of dye-semiconductor assemblies based on a semiconductor other than TiO2 for the selective aerobic oxidation, affirming the generality of cooperative photocatalysis and implying the great potential of hierarchical Nb2O5 in platforming the visible-light-induced selective transformation of organic molecules.

Nanoparticles are produced by chemical methods which are usually environmentally hazardous because of the use of various perilous chemicals and harsh reaction conditions. Bio-mediated synthesis using microbes has been proved to be a promising substitute for traditional methods to synthesize nanoparticles. Herein, based on the principles of biomimetic mineralization, a bio-mediated strategy was proposed to synthesize biocompatible barium carbonate nanoparticles (nBaCO3) in living yeast cells according to the intracellular biochemical reactions using tactfully the interaction of endogenous CO32− and exogenous Ba2+ under normal growth conditions of the yeast cells. The intracellular nBaCO3 are well-dispersed and the diameter of the nanoparticles is successfully controlled at about 5 nm under mild conditions. The bio-mediated strategy to obtain nanomaterials can be universally applied to biosynthesize other kinds of components with good biocompatibility. This biosynthesis route for barium carbonate nanoparticles mediated by the cells not only presents a green and facile design to synthesize well-tailored nanomaterials using a biomineralization-inspired strategy but may also lead to new insights for nanotechnology.

Until now, the green and facile synthesis of highly fluorescent silicon nanoparticles (SiNPs) with robust luminescent stability and favorable biocompatibility for cellular imaging is still a challe...

Two kinds of [3 + 2] cycloaddition intermediates generated from the three-component reactions of 2-bromobenzaldehydes and maleimides with amino esters or amino acids were used for a one-pot N-allylation and intramolecular Heck reactions to form pyrrolidinedione-fused hexahydropyrrolo[2,1-a]isoquinolines. The multicomponent reaction was combined with one-pot reactions to make a synthetic method with good pot, atom and step economy. MeCN was used as a preferable green solvent for the reactions.

Iridium(III) porphycene complex was synthesized and structurally characterized for the first time. The introduction of the posttransition iridium(III) ion not only significantly enhances the absorption intensity at the end of visible region, but also displays efficient singlet oxygen quantum yield (76%), which is applicable for photodynamic therapy in living cells.

Inspired by biomineralization, the first synthesis of size-tunable calcium carbonates from nanoparticles (YC-CaCO3 NPs) to nano/microspheres (YC-CaCO3 N/MSs) with a porous structure was accomplished using a facile method under the mediation of the secretion from yeast cells (YCs). The biomolecules derived from the secretion of YCs were used as conditioning and stabilizing agents to control the biosynthesis of the YC-CaCO3 materials. The morphology and crystal forms of YC-CaCO3 materials can be affected by the biomolecules from the secretion of YCs. With increasing concentrations of biomolecules, the morphologies of the obtained CaCO3 materials changed from nanoparticles to nano/microspheres with a porous structure, while the crystal forms transformed from amorphous to calcite. Functional investigations showed that YC-CaCO3 NSs with a porous structure effectively acted as anticancer drug carriers with accurate and selective drug release in tumor tissue, which suggests that they have great potential to function as a therapeutic delivery system. These application features are mainly attributed to the satisfactory biocompatibility and biodegradability, high drug-loading capacity, and pH-dependent sustained drug release performance of the porous YC-CaCO3 NSs. The biomimetic synthesis strategy of YC-CaCO3 materials mediated by YC secretion not only helps to shed light on the biomineralization mechanism in organisms, but may also lead to a new means of biosynthesizing organic–inorganic nanocomposites.

1D titanate (H2Ti3O7) nanotubes were prepared by a hydrothermal treatment of TiO2 under 10 M NaOH and ensuing acid exchange process. Here, it is discovered that H2Ti3O7 nanotubes can facilitate the merger of organic photocatalysis and TEMPO catalysis. Confined within H2Ti3O7 nanotubes, the organic photocatalyst erythrosin B (ErB) could drive the highly selective aerobic oxidation of sulfides under irradiation of green light-emitting diodes (LEDs), when 0.5 mol% of TEMPO was added as a co-catalyst. The turnover number (TON) for photocatalytic selective aerobic oxidation of thioanisole in terms of ErB is 2450, which is hitherto the best reported TON. Apart from confining the successful merger of ErB photocatalysis and TEMPO catalysis, H2Ti3O7 nanotubes not only activate O2 to generate superoxide anion radical (O2˙−), but also ensure high selectivity of sulfoxides with their abundant surface hydroxyl groups. This work represents a crucial step forward in selective oxidation reactions by materials design of dye-semiconductor assembly photocatalysts.

An AIEgen decorated porphyrin (TPETPyP) was easily obtained through a one-step reaction. The bulky TPE in TPETPyP greatly impeded the intermolecular π-π stacking of the porphyrin core, which significantly suppressed aggregation-caused quenching (ACQ) effect of TPETPyP in aqueous solution. The four pyridinium salts formed in TPETPyP also render the whole molecule water solubility, which eliminated its aggregation. TPETPyP exhibited 1O2 quantum yield as high as 0.85 in PBS. Moreover, it also showed high binding affinity to proteins, the major biotarget of 1O2. The high 1O2 quantum yield plus the great binding ability of TPETPyP toward proteins makes it a highly-efficient protein photocleaving agent. Protein electrophoresis experiments demonstrated that TPETPyP can photocleave BSA upon visible light irradiation, indicating that TPETPyP can act as a promising photosensitizer (PS) in PDT. The work here will provide a facile strategy to utilize AIEgens modified traditional PSs for photodynamic therapy (PDT).

Escherichia coli (E. coli) O157:H7 can cause many food safety incidents, which seriously affect human health and economic development. Therefore, the sensitive, accurate, and rapid determination of E. coli O157:H7 is of great significance for preventing the outbreak and spread of foodborne diseases. In this study, a carbon dots-Fe3O4 nanomaterial (CDs-Fe3O4)-based sensitive electrochemical biosensor for E. coli O157:H7 detection was developed. The CDs have good electrical conductivity, and the surface of carbon dots contains abundant carboxyl groups, which can be used to immobilize probe DNA. Meanwhile, the CDs can be used as a reducing agent to prepare CDs-Fe3O4 nanomaterial. The Fe3O4 nanomaterial can improve the performance of the electrochemical biosensor; it also can realize the recovery of CDs-Fe3O4 due to its magnetism. As expected, the electrochemical biosensor has excellent specificity of E. coli O157:H7 among other bacteria. The electrochemical biosensor also exhibited good performance for detecting E. coli O157:H7 with the detection range of 10–108 CFU/ml, and the detection limit of this electrochemical biosensor was 6.88 CFU/ml (3S/N). Furthermore, this electrochemical biosensor was successfully used for monitoring E. coli O157:H7 in milk and water samples, indicating that this electrochemical biosensor has good application prospect. More importantly, this research can provide a new idea for the detection of other bacteria and viruses.

BACKGROUND Acute liver injury (ALI) is an essential component of sepsis associated with poor outcomes. Octanoic acid (OA), a medium-chain fatty acid, has a protective effect on sepsis-induced organ damage, and autophagy is an adaptive response to sepsis. However, the underlying mechanism by which OA prevents ALI remains unknown. Therefore, we investigated whether OA-rich enteral nutrition (EN) prevented lipopolysaccharide (LPS)-induced ALI through the c-Jun N-terminal kinase (JNK)-dependent autophagy. METHODS Firstly, Sprague Dawley rats were randomly divided into four groups (sham, LPS, LPS + EN, and LPS + EN + OA) to detect the effect of OA-rich EN on LPS-induced ALI. Then, rats were randomly divided into five groups (sham, LPS, LPS + EN + OA, LPS + EN + OA + anisomycin (AN), and LPS + SP600125) to explore the mechanism by which OA-rich EN prevented ALI. EN and OA-rich EN were conducted through gastric tubes for 3 days. The liver protective effects were measured by liver histopathological changes, enzymes, inflammatory cytokines of serum and liver, the levels of autophagy, and JNK activity. RESULTS OA-rich EN inhibited JNK activity, up-regulated autophagy and prevented LPS-induced ALI. Inhibition of JNK activity conferred by SP promoted autophagy and prevented LPS-induced ALI. Moreover, the protective effect of autophagy and inhibition of JNK activity conferred by OA-rich EN on ALI was counteracted by AN. CONCLUSION OA-rich EN prevented LPS-induced ALI through JNK-dependent autophagy. This result suggested that OA-rich EN may be a therapeutic potential for ALI in patients with sepsis.

Rapid industrialization and urbanization have resulted in elevated concentrations of contaminants in the groundwaters and subsurface soils, posing a growing hazard to humans and ecosystems. The transformation of most contaminants is closely linked to the mineralogy of ferric (hydr)oxides. Sulfidation of ferric (hydr)oxides is one of the most significant biogeochemical reactions in the anoxic environments, causing reductive dissolution and recrystallization of ferric (hydr)oxides and further affecting the transformation of iron-associated contaminants. This paper provides a comprehensive review on the sulfidation process of ferric (hydr)oxides and the transformation of relevant contaminants. This review presents detailed reaction mechanisms between ferric (hydr)oxides and dissolved sulfide, and elucidates the factors (e.g. crystallinity of ferric (hydr)oxides, the ratio of sulfide concentration to the surface area concentration of ferric (hydr)oxides) that control the formation of surface associated Fe(II), iron sulfide minerals, as well as transformation of secondary minerals. Then, we summarized the transformation mechanisms of a variety of typical environmentally relevant contaminants existing in groundwater and subsurface soils, including heavy metals, metal(loid) oxyanions (arsenic, antimony, chromium), radionuclides (uranium, technetium), organic contaminants and phosphate/nitrate species. The general mechanisms of contaminant transformation involve a combination of release, reduction and re-adsorption/incorporation processes, the specific pathway of which is highly dependent on the properties of the contaminant itself and the extent of sulfidation. Moreover, the challenge of extending our knowledge towards in situ remediation, as well as further research needs are identified.

Fe(III) coagulation-precipitation process has been widely used to remove heavy metals from industrial effluents; however, the influences of organic ligands on the sequestration of different heavy metals in the Fe(III)/metal-EDTA ternary system are not well understood. In this study, the pH-dependent mechanisms of CuII-EDTA and NiII-EDTA removed by in-situ formed iron (oxy)hydroxides were studied using surface complex modeling and a suite of characterization techniques. Results of surface complex model indicated that there should be minimal difference between removal of CuII-EDTA and NiII-EDTA by iron (oxy)hydroxides if adsorption was the dominant mechanism. However, through the speciation analysis and characterization of the precipitates generated after coagulation and precipitation, we have demonstrated that at neutral pH the complexation of Fe(III) and EDTA influenced the surface properties of iron (oxy)hydroxides formed, with the higher removal of Cu2+ (compared to Ni2+) contributed by its coprecipitation with Fe(III). Moreover, at basic pH, decomplexation of CuII-EDTA occurred on the iron (oxy)hydroxides surface with the released copper ions involved in the formation of (oxy)hydroxides. The low removal of nickel (from NiII-EDTA) was ascribed to the higher conditional stability constant of NiII-EDTA. Results of this study have advanced our understanding of the complicated interactions among Fe(III), organic ligands and heavy metals in the industrial effluents, and provide insight to optimization of the process efficiency.

The crystallographic shapes of nanocrystals play critical roles in determining their physical and chemical properties. Liquid phase synthesis serves as one of the most important approaches for preparing shape-controlled nanocrystals, therefore, understanding the formation mechanisms of the thermodynamic equilibrium structures of nanocrystals in liquid solution is important. Using in situ liquid cell transmission electron microscopy (TEM), we observe for the first time the shape transformation of individual palladium nanocrystals from energy unfavored spherical shapes into equilibrium truncated octahedrons in aqueous solution. Via quantitative analysis of the shape evolution dynamics of an individual Pd nanocrystal, we find that about 10% of nanocrystal atoms were relocated during the shape transformation. The mass transport is attributed to the synergetic effect of electron beam irradiation and water environment.

In this work, we reported the synthesis of two-dimensional spinel structure of ultrathin Co2AlO4 nanosheets via dealloying and subsequent annealing processes. Oxygen vacancy defects were further introduced into Co2AlO4 nanosheets by a mild solvothermal reduction method, resulting in large electrochemical surface area and high active site densities, making the related Co atoms get electrons, and producing more empty orbitals. The positive charge of Co and Al atoms adjacent to the O vacancies in VO-rich Co2AlO4 reduced significantly, that is, more electrons are concentrated on the Co and Al atoms. Those electrons closed to the Fermi level have a promoting effect during the H2O activation. As a result, the obtained ultrathin Co2AlO4 nanosheets with oxygen vacancies show a low overpotential of 280 mV at the current density of 10 mA cm−2 and a small Tafel slope of 70.98 mV dec−1. Moreover, it also displays a remarkable stability in alkaline solution, which is superior to most of the reported Co3O4 electrocatalysts. The present work paves a new way to achieve efficient new energetic materials for sustainable community.

Bi2S3/2D-Bi2WO6 composite materials which combined 2D-Bi2WO6 with Bi2S3 nanoparticles were prepared via ion exchange method. The mass ratio of Bi2S3 nanoparticle could be modulated by changing the quantity of thioacetamide (TAA). For Bi2S3/2D-Bi2WO6 composite materials, Bi2S3 nanoparticles dispersed on the surface of Bi2WO6 nanosheets. The photocatalytic activity was evaluated by photodegradation rhodamine B (RhB) under visible light. RhB was photodegraded nearly completely by BWS-2, while only 67% was photodegraded by Bi2WO6 nanosheet after 5 h' visible light irradiation. Based on the optical and electrochemical measurements, Bi2S3/2D-Bi2WO6 composite materials have prolonged carriers' lifetime, improved carriers' separation efficiency and decreased carriers' recombination efficiency. These results endow Bi2S3/2D-Bi2WO6 composite materials with high photocatalytic activities.

The application of nanoscale zero-valent iron (nZVI) for the degradation of contaminants has been extensively investigated, however, few studies have focused on degradation in high salinity environments. In this study, the ability of bare and carboxymethyl cellulose (CMC)-coated bimetallic Pd-nZVI particles to degrade 33′44′-tetrachlorobiphenyl in high saline water (SW) is examined with particular attention given to the effects of ethylenediaminetetraacetic acid (EDTA) on the rate of degradation. EDTA enhances the reactivity of Pd-nZVI in SW, with evidence provided to link this to the removal of the passivating layer. Additionally, a conceptual model is proposed which provides a quantitative description of the removal of these iron oxide layers in the presence of EDTA. An optimum EDTA to bare Pd-nZVI molar ratio of 0.1 exists, with insufficient EDTA unable to remove the passivating layer whilst excess EDTA results in Fe loss and enhanced agglomeration due to magnetic attraction of the bare Fe(0) particles. In contrast, CMC-coating of Pd-nZVI assemblages actually impedes degradation, despite the coated particles displaying a smaller average size compared to uncoated particles, with even the presence of EDTA in this case not significantly improving degradation. The reduced reactivity in the presence of CMC is primarily attributed to the effect of CMC on the association of Pd with nZVI particles. In particular, the presence of CMC reduced the total amount of Pd incorporated with the stabilized particles compared to the non-stabilized particles. Additionally, the presence of CMC results in less Pd present in its reactive zero-valent oxidation state.

Trifunctional catalysts show a great potential for use in a power-to-gas water-splitting devices for hydrogen gas production, powered by an integrated rechargeable zinc-air battery. None of the currently available commercial electrocatalysts is low cost, and they do not possess excellent catalytic activity and durability at the same time, which is the main barrier to the broad implementation of these technologies. Herein, we design and develop a novel nanostructured trifunctional electrocatalyst that is capable of catalyzing oxygen/hydrogen evolution and oxygen reduction reactions. The combination of non-precious Co, Co9S8, and S, N co-doped graphitic carbon synergistically provides highly active sites for efficient catalytic reactions, while the unique tubular morphology and hierarchically porous microstructure not only benefit fast access to active sites but also ensure a robust composite structure for durability. When applied to zinc-air batteries and water splitting, these systems exhibit performance superior to those of commercial precious electrocatalysts (e.g., Pt/C and Ir/C).

A [4 + 2] annulation involving cascade Knoevenagel, aza-Wittig and dehydrofluorination reactions is developed for the synthesis of substituted quinolin-4-ols including analogs bearing CF2H, CF3, and C2F5 groups. This simple and highly efficient method is also applicable for the synthesis of substituted quinolines. A number of reported biologically active compounds can be readily prepared by this one-pot synthesis. Green chemistry metrics analysis of the new reaction processes provided favorable results.

Sulfidation of silver nanoparticles (Ag-NPs) readily occurs in both urban sewage systems and sulfur-rich natural environments with formation of silver sulfide nanoparticles (Ag2S-NPs). It is essential to understand the transformation and fate of Ag2S-NPs in order to fully evaluate environmental impact of Ag-NPs. The review focuses on the formation and transformation of Ag2S-NPs from both thermodynamic and kinetic perspectives, particularly (i) the formation mechanism of Ag2S in various environmental scenarios, (ii) redox transformation of Ag2S caused by oxidation of S(−II) and (iii) effects of environmental matrices on the formation and transformation processes. In most cases, sulfidation of Ag-NPs causes a dramatic decrease in their toxicity due to the extremely low solubility of Ag2S, potentially restraining their short-term environmental impact. However, the transformation of Ag2S-NPs with potential release of Ag+ and in situ formation of Ag0 and Ag0/Ag2S-NPs hetero-nanostructures may possibly increase the toxicity. Mechanistically-based kinetic modeling has been proposed here to quantitatively describe the rate and extent of the transformation of Ag2S-NPs, with such models of value, at least, in validating proposed transformation mechanisms of Ag2S-NPs and, at best, in predicting their transformation behaviors under realistic environmental conditions.

A new synthetic method for diastereoselective synthesis of tetrahydro-pyrrolo[1,2-d][1,4]benzodiazepines and tetrahydro-pyrrolo[1,2-d][1,4]diazepinones is developed which involves 1,3-dipolar cycloaddition, N-alkylation or N-acylation and Staudinger/aza-Wittig reactions. This one-pot and three-step synthesis of four components gave two different heterocyclic scaffolds. Green chemistry metrics analysis of the reaction process provided favorable results.

High sequence homology among miRNA members challenges miRNA analysis. In this paper, we developed a simple and highly selective method based on a novel G-triplex molecular beacon (MBG3) and duplex-specific nuclease signal amplification (DSNSA) for miRNA detection. Herein, this MBG3 is a label-free molecular beacon with a special G-triplex probe. The excellent controllablity of the G-triplex probe allowed our MBG3 to have a short stem, which protected it from DSN digestion. Therefore, DSN cleavage induced false positive signals in most DSN signal amplification strategies have been minimised efficiently without special modifications. Importantly, the improved recognition ability of MBG3, together with the sensitive substrate selectivity of DSN, makes our novel method suitable for miRNA detection with high selectivity. The signal response of similar miRNA sequences with one-base difference has been reduced from 37% to 8% compared to the traditional linear ssDNA probe-DSN-based method.

Multicomponent reactions (MCRs) involving a minimum of three reactants or reaction centers are conducted in one pot and with a single operational step. This synthetic method has a good pot, atom and step economy in the preparation of diverse and complex molecular scaffolds. Consecutive MCRs, also known as sequential or multiple MCRs, by combining two or more MCRs, exhibit even higher synthetic efficiency, product structural diversity, and molecular complexity. This review article highlights the Ugi, Groebke-Blackburn-Bienaymé, Biginelli, Huisgen, Petasis, Gewald, and Asinger reaction-initiated consecutive MCRs.

Multicomponent reactions (MCRs) have inherent advantages in pot, atom, and step economy (PASE). This important green synthetic approach has gained increasing attention due to high efficiency, minimal waste, saving resources, and straightforward procedures. Presented in this review article are the recent development on 5-compoment reactions (5CRs) of the following six types: (I) five different molecules A + B + C + D + E; pseudo-5CRs including (II) 2A + B + C + D, (III) 2A + 2B + C, (IV) 3A + B + C, (V) 3A + 2B, and (VI) 4A + B. 5CRs with more than five-reaction centers are also included.

Pickering emulsion plays an important role in various industrial fields including food, catalysis, and bioscience. Soy protein isolate (SPI) has been proved feasible for stabilizing Pickering emulsion after modification, though such methods were either difficult to proceed or application restrictive. Herein, we report a simple fabrication of oil-in-water Pickering emulsion using a complex of SPI and carbon nanotubes (CNTs)/carboxymethyl cellulose sodium (CMC-Na). The stability of our emulsion could be kept at a wide range of CNTs diameter, oil fraction, and pH, while the emulsion droplet size might be controlled through the tuning of pH and dispersed phase solvent as well. A strong interaction between SPI and CNTs/CMC-Na is a key factor for the homogeneous distribution of CNTs at the aqueous���organic interface, which benefits the Pickering emulsion formation. Our work will offer some useful thoughts for improving the stability of protein-integrated emulsion.

Thallium (Tl) often enters the environment via mineral exploitation and utilization. The main restriction of Tl removal is the interference of high concentrations of coexisting ions in wastewater, therefore, enhancing the selectivity for Tl is essential to its treatment. Magnetic Prussian blue particles (Fe3O4@PB), an ion-sieving material with an open structure, were synthesized through a “one-pot” method at room temperature for the highly selective removal of Tl+. The removal percentage of Tl+ was over 92% even when the concentration of coexisting ions (e.g. Zn2+, Cd2+, Cu2+, and Pb2+) were 10,000 times higher than the initial concentration of Tl+. The maximal experimental removal capacity was 528 mg Tl/g Fe3O4@PB, and the removal percentage remained steady at pH 3–10. The high selectivity of Fe3O4@PB for Tl+ is attributed to the fact that hydrated Tl+ has a smaller hydrated diameter and a lower hydration free energy than other coexisting ions, while the rapid adsorption kinetics of Tl+ results from the negative surface charge and the network of nanocapillaries of the Fe3O4@PB. Overall, a new low-cost material that is easy to synthesize and has superior Tl+ removal capacity with extremely high selectivity for Tl+ was obtained for effective magnetic removal of thallium from wastewater.

Gastric cancer (GC) is a malignancy for which effective therapeutic drugs are limited. Podofilox exhibits antitumor effects in various types of cancer; however, whether it may inhibit GC growth remains unknown. The aim of the present study was to investigate the role of podofilox in GC. Cell Counting Kit-8, colony formation and cell cycle assays were used to detect the role of podofilox on cellular proliferation and the cell cycle, respectively. A microarray was used to detect the transcriptional changes induced by podofilox in GC cells. The results of the present study demonstrated that podofilox inhibited GC cell proliferation and colony formation. The half maximal inhibitory concentration of podofilox in AGS and HGC-27 cells was 2.327 and 1.981 nM, respectively. In addition, treatment with podofilox induced G0/G1 cell cycle arrest. Molecular analysis based on microarray data demonstrated that podofilox altered the expression levels of genes involved in the cell cycle, c-Myc and p53 signaling. Autophagy-related 10 (ATG10), which was highly expressed in GC tissues, was also downregulated by podofilox, as demonstrated by the results of the microarray analysis and immunoblotting. To determine the involvement of ATG10 in GC, ATG10 was knocked down in GC cells by small interfering RNA, which suppressed the proliferation and colony formation of GC cells compared with those observed in the control-transfected cells. Taken together, the results of the present study suggested that podofilox may inhibit GC cell proliferation by preventing the cell cycle progression and regulating the c-Myc/ATG10 signaling pathway.

Musk ketone exerts antiproliferative effects on several types of cancer, such as lung and breast cancer. However, the effects and underlying mechanisms of action of musk ketone in gastric cancer (GC) are poorly understood. The present study aimed to investigate the effects of musk ketone in GC cells. The present study indicated that musk ketone exerted significant anticancer effects on GC cells. The IC50 values of musk ketone were 4.2 and 10.06 µM in AGS and HGC‑27 cells, respectively. Low dosage of musk ketone significantly suppressed the proliferation and colony formation of AGS and HGC‑27 cells. Cell cycle arrest and apoptosis were induced by musk ketone. Furthermore, microarray data indicated that musk ketone treatment led to downregulation of various genes, including sorbin and SH3 domain containing 2 (SORBS2). Reverse transcription‑quantitative PCR and immunoblotting results indicated that musk ketone repressed mRNA and protein expression levels of SORBS2. It was also shown that knockdown of SORBS2 inhibited the proliferation and colony formation of HGC‑27 cells. The antiproliferative effects of musk ketone were decreased in HGC‑27 cells with SORBS2 silencing. In summary, the present study indicated that musk ketone suppressed the proliferation and growth of GC partly by downregulating SORBS2 expression.

Here, a fully integrated multicolor immunosensor was developed for sensitive and reliable semiquantitative analysis of HIV-1 p24, which integrates the multistep reactions of horseradish peroxidase (HRP)-linked immunoassay and gold nanorod (AuNR)-based multicolor assay into a single microfluidic chip. The HRP-linked immunoassay functions by moving magnetic beads bound to a capture antibody through different aqueous phases containing immunoassay reagents. HRP-catalyzed oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) is used to mediate AuNRs etching for producing various color changes. Multiple etching processes can be activated by simple mixing of the reagents from the reagent storage reservoir. The fully integrated strategy with sample-in answer-out capability is initiated by simple chip manipulation and finally concluded by converting recognition of antigen-antibody into a vivid color variation for direct visualization and semiquantitative analysis. By bare eye observation, our integrated multicolor immunosensor allows sensitive and reliable semiquantitative analysis of HIV-1 p24 within 1 h. The microfluidic chip device demonstrated here simplifies the operation significantly and thus allows broader application of a multicolor immunosensor for point of care (POC) testing in low-resource settings.

A three-dimensional notched-elliptical microdisk with a wavelength-size notch on the boundary is proposed as a multi-wavelength and unidirectional emission lasing source. The device contains multiple properly designed two-dimensional whispering gallery mode-based polymer notched microdisks with different dimensions for use as a multi-wavelength source. It can have a relatively high optical quality factor of 4000, unidirectional emission with low far-field divergence ∼4°, and the efficiency of emission is as high as 84.2%. The effect of the notch size on the far-field divergence is analyzed, and the multi-wavelength lasing performance is characterized, demonstrating that the resonator is robust and reliable. This work paves a unique but generic way for the design of compact multi-wavelength microlasers.

We propose a biomimetic strategy to construct engineered yeast cells (EYCs) by building intracellular silica nanoscaffolds as biomimetic organelles. These nanosilica-based organelles can coordinate with loaded drug and yeast as a shell could prevent drug leakage. In vivo results show that EYCs serve as a dually responsive drug delivery system, targeted with extracellular caps (folate) and triggered by intracellular SiO2 at the low pH of cancer tissue.

Sequential inter- and intramolecular [3 + 2] cycloadditions of azomethine ylides are developed for the one-pot and diastereoselective synthesis of highly condensed heterocyclic systems containing pyrrolidine and up to seven stereocenters. It has high synthetic efficiency and operational simplicity, and only water was generated as a byproduct.

Manufacturing is the foundation of China's economy and accounts for a large proportion of China's CO2 emissions. In this study, the structural path decomposition (SPD) methodology, based on an environmental input-output model, was used to find critical supply chain paths that drive changes in CO2 life cycle in China's manufacturing industry from 1992 to 2012. The changes in CO2 emissions were decomposed into three main factors: carbon emissions intensity, input-output structure, and final demand. In this study, the “weighted average decompositions” method of structural decomposition analysis and the non-comparable input-output table were first applied to the SPD method to obtain accurate results. The results indicate that higher-order paths, especially the paths that started from the “Smelting and Rolling of Metals” and the “Production and Supply of Electricity and Steam” sectors, led to an increase in carbon emissions. This was mainly due to the extension of the industrial chain as well as policy priorities. Moreover, CO2 emissions from the “Chemical Industry”, “Manufacture of Nonmetallic Mineral Products”, and “Smelting and Rolling of Metals” sectors were mainly induced by the increase of final export demands. Based on the results of this study, relevant policy changes have also been recommended.

A unique mineralized cell-based functional platform with biogenic intracellular hydroxyapatite nanoscaffolds (nHAP@yeasts) has been intelligently constructed using a biomimetic mineralization approach. Such a platform not only preserves the nature and functions of cells but also possesses intracellular nanoscaffolds, which endow the mineralized cells with novel functions in biological and nanotechnological applications. Benefiting from their unique organism shell and inorganic core, the nHAP@yeasts are biocompatible and have a large loading capacity for drugs. Such anaerobic microorganisms could be beneficial as drug carriers for the effective delivery and release of loaded drugs in tumors because they prefer to locate and grow in reduced oxygen surroundings. A functional investigation indicated that the nHAP@yeasts, functionalized with folic acid (nHAP@yeasts-FA) as cell-based carriers, showed dual responsive release profiles based on the FA dependency of tumors and the pH-sensitivity of the HAP nanoparticles, and they significantly inhibited tumor growth while displaying low toxicity. This study for the first time provides a bio-friendly strategy to biosynthesize a mineralized cell-based functional platform with biogenic intracellular nanominerals (carbonate, sulfides, selenides, metals, etc.) for biological and nanotechnological application.

Visible light-driven photocatalysis over semiconductors has emerged as one of the most desired strategies for animating diverse selective chemical transformations. Herein, one-dimensional (1D) Nb2O5 nanorods with a specific surface area of 264 m2•g−1 were synthesized via a straightforward hydrothermal method. Thereafter, an efficient visible light photocatalyst was constructed by in-situ anchoring of alizarin red S (ARS) onto the Nb2O5 nanorods to afford ARS-Nb2O5. Resultantly, the ARS-Nb2O5 nanorods can facilitate the selective aerobic oxidation of amines into imines, affording about twice of the result over 3D hierarchical Nb2O5. Notably, 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO) could synchronize the intricate electron and proton transfers between ARS-Nb2O5 nanorods, amines, and superoxide (O2•−). In most cases, the green light-driven primary and secondary amines into imines could be completed with about 95% selectivity within 2 h. This work highlights the dimension of designing semiconductor materials to anchor visible light-active molecules for selective oxidation reactions under benign conditions.