Label-free "signal-off" PEC aptasensor for determination of kanamycin based on 3D nanoflower-like FeIn2S4/CdS Z-scheme heterostructures.

Highly photoactive 3D nanoflower-like FeIn2S4/CdS heterostructures were synthesized by hydrothermal treatment and low-temperature cation exchange. The FeIn2S4/CdS displayed 14.5 times signal amplification in contrast to FeIn2S4 alone. It was applied as a photoactive substrate to construct a label-free photoelectrochemical (PEC) aptasensor for ultrasensitive determination of kanamycin (KAN). Under the optimal conditions, the constructed PEC aptasensor displayed a wide linear range (5.0 × 10-4 ~ 5.0 × 101 ng mL-1) and a low detection limit (S/N = 3) of 40.01 fg mL-1. This study provides some constructive insights for preparation of advanced photoactive materials and exhibits great potential for quantitative determination of antibiotics in foods and environmental samples.

Environmentally relevant concentrations of arsenic induces apoptosis in the early life stage of zebrafish.

Arsenic (As) in the aquatic environment is a considerable environmental issue, previous studies have reported the toxic effects of low concentrations (≤ 150 µg/L) of As on fish. However, limited information is available regarding the impact of low levels of As on apoptosis. To evaluate this, zebrafish embryos were exposed to different concentrations (0, 25, 50, 75, and 150 µg/L) of As (arsenite [AsIII] and arsenate [AsV]) for 120 h. Our results indicated that low concentrations of AsIII exposure significantly inhibited the survival of zebrafish larvae, and significantly increased the transcription of Caspase-9 and Caspase-3, the ratio of Bax/Bcl-2 transcription, and protein levels of Caspase-3. In contrast, AsV decreased the ratios of Bax/Bcl-2 transcription and protein levels, as well as protein levels of Caspase-3. Our data demonstrated that AsIII and AsV exert different toxic effects, AsIII induced apoptosis via the mitochondrial pathway and the extrinsic pathway, while AsV induced apoptosis only via the mitochondrial pathway.

Green synthesis of peptide-templated fluorescent copper nanoclusters for temperature sensing and cellular imaging.

A simple and green approach was developed for the preparation of fluorescent Cu nanoclusters (NCs) using the artificial peptide CLEDNN as a template. The as-synthesized Cu NCs exhibited a high fluorescence quantum yield (7.3%) and good stability, along with excitation and temperature dependent fluorescent properties, which could be employed for temperature sensing. Further investigations demonstrated low toxicity of Cu NCs for cellular imaging.

In situ produced Co9S8 nanoclusters/Co/Mn-S, N multi-doped 3D porous carbon derived from eriochrome black T as an effective bifunctional oxygen electrocatalyst for rechargeable Zn-air batteries.

Construction of high-efficiency, low cost and stable non-noble metal catalyst on air cathode is of great importance for design and assembly of rechargeable Zn-air battery. Eriochrome black T (EBT) has phenolic hydroxyl and -N=Ν- groups, which provides multiple coordination sites for metal ions. Herein, Co9S8 nanoclusters implanted in Co/Mn-S,N multi-doped porous carbon (Co9S8@Co/Mn-S,N-PC) are fabricated with the mixture (i.e. EBT, metal precursors and dicyandiamide) by a coordination regulated pyrolysis strategy. Specifically, EBT effectively chelates with the Co and Mn ions, resulting in multiple incorporation and fine modulation of the carbon electronic structures. Meanwhile, its sulfonic acid groups are reduced at such high temperature, accompanied by simultaneously embedding S element in the carbon, ultimately in situ forming Co9S8 nanoclusters. The Co9S8@Co/Mn-S,N-PC performs as an effective bifunctional oxygen catalyst, displaying a positive half-wave potential of 0.85 V and a large limiting current density of 5.89 mA cm-2 for oxygen reduction reaction (ORR) in alkaline media, coupled with a small overpotential of 320 mV at 10 mA cm-2 towards oxygen evolution reaction (OER), outperforming commercial Pt/C and RuO2 catalysts, respectively. Furthermore, the assembled rechargeable Zn-air battery with Co9S8@Co/Mn-S,N-PC exhibits the much better charge/discharge performance and long-term durability (210 h, 630 cycles). This research opens an instructive avenue to develop high-efficient and stable bifunctional oxygen electrocatalysts in energy transformation and storage devices.

Ecotoxicological assessment of spent battery extract using zebrafish embryotoxicity test: A multi-biomarker approach.

Water environmental pollution caused by spent batteries is a nonignorable environmental issue. In this study, the early life stage of zebrafish was employed to assess the environmental risk of spent batteries after exposure to 0, 1%, 2%, 5% and 10% spent battery extract for 120 h. Our results clearly indicated that spent battery extract can significantly decrease the survival rate, hatching rate and body length and increase heart rate. Moreover, spent battery extract exposure-induced zebrafish larvae generate oxidative stress and inhibit the mRNA transcriptional levels of heat shock protein (HSP70) and metallothionein (MT) genes. These results showed that the spent batteries not only affected the survival and development performance of zebrafish at an early life stage but also caused oxidative stress and interfered with the detoxification of zebrafish. This study provided novel insight into spent battery induced toxicity in the early life stage of fish.

One-step pyrolysis synthesis of nitrogen, manganese-codoped porous carbon encapsulated cobalt-iron nanoparticles with superior catalytic activity for oxygen reduction reaction.

Replacing precious metal catalysts with low-price and abundant catalysts is one of urgent goals for green and sustainable energy development. It is imperative yet challenging to search low-cost, high-efficiency, and long-durability electrocatalysts for oxygen reduction reaction (ORR) in energy conversion devices. Herein, three-dimensional low-cost Co3Fe7 nanoparticles/nitrogen, manganese-codoped porous carbon (Co3Fe7/N, Mn-PC) was synthesized with the mixture of dicyandiamide, cobalt (II) tetramethoxyphenylporphyrin (Co(II)TMOPP), hemin, and manganese acetate by one-step pyrolysis and then acid etching. The resultant Co3Fe7/N, Mn-PC exhibited excellent durability and prominent ORR activity with more positive onset potential (Eonset, 0.98 V) and half-wave potential (E1/2, 0.87 V) in 0.1 M KOH electrolyte, coupled with strong methanol resistance. The pyrolysis temperature and optimal balance of graphite with pyridine-nitrogen are of significance for the ORR performance. The prepared Co3Fe7/N, Mn-PC displayed excellent ORR performance over commercial Pt/C in the identical environment. It was ascribed to the uniform 3D architecture, Mn- and N-doping effects by finely adjusting the electronic structures, coupled with the synergistic catalytic effects of multi-compositions and multi-active sites. This work provides some constructive guidelines for preparation of low-cost and high-efficiency ORR electrocatalysts.

Engineering 3D hierarchical thorn-like PtPdNiCu alloyed nanotripods with enhanced performances for methanol and ethanol electrooxidation.

Developing efficient and stable electrocatalysts with three-dimensional (3D) hierarchical nanostructures is extremely important in practical applications of direct alcohol fuel cells. Herein, 3D hierarchical thorn-like multi-metallic PtPdNiCu alloyed nanotripods (PtPdNiCu TNTPs) were efficiently fabricated by a one-pot aqueous method, in which Pluronic F127 performed as the structure-director and dispersing agent. The as-prepared PtPdNiCu TNTPs exhibited distinct electrocatalytic activity for methanol oxidation reaction (MOR) with a mass activity (MA) of 1.465 A mg-1Pd, which is superior to commercial Pt/C (0.925 A mg-1Pd) in 1.0 M KOH solution, along with the greater MA (1.019 A mg-1Pd) for ethanol oxidation reaction (EOR) than Pt/C (0.712 A mg-1Pd). This work would provide an impetus for rationally constructing multimetal nanomaterials to commercial implementation of advanced alcohol fuel cells.

3D highly branched PtCoRh nanoassemblies: Glycine-assisted solvothermal synthesis and superior catalytic activity for alcohol oxidation.

Advanced Pt-based ternary nanocatalysts display dramatically enhanced utilization efficiency of Pt alternative to mono- and bi-counterparts, owing to the synergistic effects of the tri-metals. Herein, multicomponent uniform 3D PtCoRh highly branched nanoassemblies (HBNAs) were prepared by glycine-assisted one-pot solvothermal method in oleylamine (OAm). The effects of the precursor types, reaction time and amount of glycine were critically investigated in this synthesis. The as-prepared PtCoRh HBNAs displayed outstanding electrocatalytic activity and improved stability towards ethanol oxidation reaction (EOR) and methanol oxidation reaction (MOR) in 1 M KOH electrolyte, whose mass/specific activities were 1.75 A mg-1/4.03 mA cm-2 and 0.98 A mg-1/2.34 mA cm-2, respectively, which were remarkably higher than commercial Pt/C (0.85 A mg-1/4.03 mA cm-2 and 0.47 A mg-1/0.89 mA cm-2). This study provides some novel guidelines to fabricate advanced multimetallic electrocatalysts for practical applications in direct alcohol fuel cells (DAFCs).

Facile synthesis of bimetallic gold-palladium nanocrystals as effective and durable advanced catalysts for improved electrocatalytic performances of ethylene glycol and glycerol oxidation.

In this work, well-defined bimetallic AuPd alloyed nanocrystals (AuPd NCs) were facilely synthesized by a straightforward and controllable one-step wet-chemical strategy, using a biomolecule (L-hydroxyproline, L-Hyp) as the green stabilizer and the structure-directing agent. Their morphology, size, composition, crystal structures and growth mechanism were investigated by a series of techniques. The synthesized architectures exhibited enlarged electrochemically active surface area (ECSA), improved catalytic activity, enhanced durability and stability towards ethylene glycol oxidation reaction (EGOR) and glycerol oxidation reaction (GOR) in alkaline electrolytes in comparison with commercial Pd black catalyst.

Melamine-assisted solvothermal synthesis of PtNi nanodentrites as highly efficient and durable electrocatalyst for hydrogen evolution reaction.

Rational design of highly efficient and durable electrocatalysts for hydrogen evolution reaction (HER) is of prime importance for renewable and sustainable energy. Herein, PtNi nanodentrites (PtNi NDs) were facilely synthesized in oleylamine (OAm) by a one-pot solvothermal method, using melamine and cetyltrimethylammonium chloride (CTAC) as co-structure-directing agents. The obtained catalyst showed superior catalytic activity and enhanced durability for HER relative to commercial Pt/C, home-made PtNi3 nanocrystals (NCs) and Pt3Ni NCs both in alkaline and acidic media. The enhanced HER activities are attributed to bimetallic synergies and interface structures in PtNi NDs. This work provides an effective strategy to prepare highly efficient and durable electrocatalysts for HER.

One-pot aqueous fabrication of reduced graphene oxide supported porous PtAg alloy nanoflowers to greatly boost catalytic performances for oxygen reduction and hydrogen evolution.

Herein, reduced graphene oxide supported porous PtAg alloy nanoflowers (PtAg NFs/rGO) were synthesized by a simple one-pot aqueous method using pyridinium-based dicationic ionic liquid (1,4-bis(pyridinium)butane dibromide, Bpb-2Br) as the new structure-director and stabilizing agent. The products were characterized by a series of techniques. The obtained nanocomposite had more positive onset potential (1.03 V) for oxygen reduction reaction (ORR) in alkaline electrolyte than those of commercial Pt/C (50 wt%, 0.96 V) and home-made Pt nanoparticles (NPs)/rGO (Pt NPs/rGO, 0.97 V), showing the enhanced catalytic performance for hydrogen evolution reaction (HER) with the positive onset potential (-26 mV) and a small Tafel slope (31 mV dec-1) relative to Pt/C (-18 mV, 31 mV dec-1) and Pt NPs/rGO (-42 mV, 36 mV dec-1) in 0.5 M H2SO4.

Simple one-pot aqueous synthesis of AuPd alloy nanocrystals/reduced graphene oxide as highly efficient and stable electrocatalyst for oxygen reduction and hydrogen evolution reactions.

Herein, we develop a simple one-pot aqueous method to prepare AuPd alloy nanocrystals on reduced graphene oxide (AuPd NCs/rGO), by using 1-acetyl-4-(p-hydroxyphenyl) piperazine (AHPP) as the reductant, stabilizing agent and structure-director, without any other additives (e.g., seed, surfactant or polymer). The product is mainly characterized by transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction and thermogravimetric analysis. The obtained AuPd NCs/rGO displays enlarged electrochemically active surface area and superior catalytic performances toward oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER) relative to Pt/C, Pd/C, Pd/rGO and Au/rGO catalysts, showing promising applications in energy storage and conversion.

One-pot synthesis of hollow AgPt alloyed nanocrystals with enhanced electrocatalytic activity for hydrogen evolution and oxygen reduction reactions.

Herein, a simple one-pot aqueous method was developed for the fabrication of uniform hollow bimetallic AgPt alloyed nanocrystals (H-AgPt NCs) by using 5-aminoorotic acid (5-amino-2,6-dioxo-1,2,3,6-tetrahydropyrimidine-4-carboxylic acid) as a growth-directing agent, without any seed, organic solvent or template involved. The prepared H-AgPt NCs displayed enhanced electrocatalytic activity for hydrogen evolution reaction (HER) with a more positive onset overpotential (ηonset) of -28mV and a smaller Tafel slope of 40mVdec-1 relative to commercial Pt black (-34mV, 50mVdec-1) and Pt/C (20wt.%, -33mV, 33mVdec-1) in 0.5M H2SO4. Meanwhile, the obtained catalyst exhibited improved catalytic features toward oxygen reduction reaction (ORR) with a positive ηonset (0.916V) and enhanced kinetic current density (243.23mAmg-1Pt) in 0.1M HClO4 at 0.850V compared with Pt black (0.876V, 25.85mAmg-1Pt).

A polypeptide-mediated synthesis of green fluorescent gold nanoclusters for Fe3+ sensing and bioimaging.

In this paper, growth hormone releasing peptide-6 (GHRP-6) is a bioactive polypeptide and acts as the reducing agent and capping ligand for synthesis of bright green fluorescent gold nanoclusters (GHRP-6-Au NCs) by a simple and environmental-friendly aqueous method, with the assistance of NaBr as the fluorescent sensitizer. The obtained GHRP-6-Au NCs had high fluorescent quantum yield (10.7%), and the fluorescence was strongly quenched by the existence of trace Fe3+. Thus, a new and highly sensitive sensor for the assay of Fe3+ was constructed based on the analyte-induced fluorescent quenching mechanism. The sensor had a low detection limit of 1.4µM (S/N=3) and a wide linear range of 2-1000µM. Besides, GHRP-6-Au NCs exhibited low cytotoxicity and high biocompatibility for cell imaging.

[Determination of vitamin C in the Vc yinqiao tablet by diffuse reflectance FTIR].

OBJECTIVE: To establish a method to determine Vitamin C in the Vc Yinqiao Tablets. METHOD: Diffuse Reflectance in FTIR was used to determination of Vitamin C in the Vc Yinqiao tablets. RESULT: The content of Vitamin C could be obtained directly, and the relationship between the absorbance and the concen tration was linear. The average recovery rate of Vitamin C was 98.69%, and RSD was 0.33%. CONCLUSION: The method is simple, accurate and reliable, which may well be used for the determination of Vitamin C in the Vc Yinqiao Tablet.

Gelatin-assisted hydrothermal synthesis of single crystalline zinc oxide nanostars and their photocatalytic properties.

Biotemplate-assisted approach is simple and friendly to the environment. With the assistance of gelatin as a soft biotemplate and a structure-directing agent, star-like zinc oxide (ZnO) nanostructures have been prepared by assembly of well-defined nanorods under hydrothermal conditions. Their morphology and structures were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and transmission electron microscopy (TEM). The growth mechanism of the ZnO nanostars is also investigated. The as-prepared ZnO nanostars display high photocatalytic activity toward the degradation of methyl orange (MO) under ultraviolet (UV) irradiation.

Functional magnetic resonance imaging of methamphetamine craving.

The study aimed to explore the abnormal activation of special brain areas associated with methamphetamine craving using functional magnetic resonance imaging (fMRI) and to reveal the neurobiological basis of addiction. Twenty-six methamphetamine addicts and 26 healthy subjects were scanned by brain fMRI while watching pictures of happy, sad, or methamphetamine to acquire resource data. SPM5 was used to analyze fMRI data to get related brain activation map, and it was found that methamphetamine addicts had high brain activation in cingulate and low activation in frontal lobe when watching methamphetamine-cue pictures. This study demonstrated that methamphetamine addicts had emotion-related brain activation abnormalities.