Self-supporting multi-channel Janus carbon fibers: A new strategy to achieve an efficient bifunctional electrocatalyst for overall water splitting.

A new type of self-supporting multi-channel Janus carbon fibers with efficient water splitting has been successfully manufactured using a specially designed parallel spinneret through electrospinning technology and subsequent carbonization technique. Every single Janus fiber composes of a half side of Mo2C and the other half side of Ni components as Mo2C, Ni embedded in N-doped multi-channel Janus carbon fibers ([Mo2C/C]//[Ni/C]-NMCFs) for overall water splitting. Under optimized condition, the hydrogen evolution reaction overpotential of [Mo2C/C]//[Ni/C]-NMCFs (62 mV) is just 24 mV higher than 20 wt% Pt/C (38 mV) at a current density of 10 mA cm-2. Furthermore, it achieves current density of 10 mA cm-2 to require an overpotential of 324 mV for oxygen evolution reaction. Additionally, the cell assembled by the identical [Mo2C/C]//[Ni/C]-NMCFs catalyst as both the cathode and anode needs only 1.607 V at a current density of 10 mA cm-2, which is only 0.022 V higher than that of Pt/C-IrO2 electrodes. Moreover, [Mo2C/C]//[Ni/C]-NMCFs catalyst also exhibits a long-term stability. The synergistic effect and unique heterostructure of Mo2C and Ni enhance the catalytic activity.

Simultaneous Visual Detection and Removal of Cu2+ with Electrospun Self-Supporting Flexible Amidated Polyacrylonitrile/Branched Polyethyleneimine Nanofiber Membranes.

Sensitive detection and effective removal of copper ions (Cu2+) from water are still arduous tasks required to protect public health and environmental safety because of the serious impacts of Cu2+ on humans and other organisms. Herein, we report the design and fabrication of self-supporting flexible amidated polyacrylonitrile/branched polyethyleneimine nanofiber membranes (abbreviated as aPAN/BPEI NMs) via facile electrospinning and a subsequent hydrothermal method, which are used not only as strips for the visual detection of Cu2+ but also as effective adsorbents for the removal of Cu2+ from water. Because aPAN/BPEI NMs are self-supporting, they can be easily removed from the solution to reduce secondary pollution to the environment. Based on the high Cu2+ binding capacity of BPEI, Cu2+ ions are adsorbed on the aPAN/BPEI NMs, which leads to the appearance of new absorbance bands at 280 and 636 nm and a color change from yellow to blue. aPAN/BPEI NMs are utilized for the visual detection of Cu2+ with a linear range of 50-700 µM and limits of detection of 11.5 and 4.8 µM (absorption peaks at 280 and 636 nm). More importantly, aPAN/BPEI NMs exhibit excellent selectivity and certain recovery with a simple treatment. Furthermore, by utilizing the adsorption characteristics of Cu2+ in aqueous media, it can be effectively removed by aPAN/BPEI NMs with a remarkable adsorption capacity of 209.53 mg·g-1. Additionally, the removal of Cu2+ by aPAN/BPEI NMs does not exhibit interference by other foreign ions. The adsorption process conforms well to the pseudo-second order (PSO) kinetic model and Jovanovich model, proving that adsorption occurs via chemical and monolayer adsorption mechanisms. Accordingly, this work will provide theoretical and technical support for the design and fabrication of novel heavy metal ion detection-removal integrated materials exhibiting high sensitivity and strong adsorption.

Cobalt-iron selenides embedded in porous carbon nanofibers for simultaneous electrochemical detection of trace of hydroquinone, catechol and resorcinol.

In this study, cobalt-iron selenides embedded in porous carbon nanofibers (CoFe2Se4/PCF), derived from Prussian blue analogues, was prepared as a novel phenolic sensor. The obtained CoFe2Se4/PCF nanocomposites show three-dimensional (3D) networks nanostructures that can supply a desirable conductive network to accelerate electron transfer and avoid the aggregation of CoFe2Se4 nanoparticles. Electrochemical detection of hydroquinone (HQ), catechol (CC) and resorcinol (RS), at CoFe2Se4/PCF modified glassy carbon electrode (GCE) were researched. The results show the obtained 3D CoFe2Se4/PCF/GCE exhibits excellent electrochemical properties towards the simultaneous testing trace of HQ, CC and RS. The obtained electrode provides wide linear ranges of 0.5-200, 0.5-190 and 5-350 µM and low detection limit of 0.13, 0.15 and 1.36 µM for HQ, CC and RS, respectively. The as-prepared phenolic sensor displays satisfied selectivity and long-term storage stability. In addition, the constructed sensor can be used to determine HQ, CC and RS in actual samples.

Effect of miR-140-5p on the regulation of proliferation and apoptosis in NSCLC and its underlying mechanism.

Non-small cell lung cancer (NSCLC) is the most common type of lung cancer accounting for ~80% of lung cancer cases. According to novel research, numerous microRNAs (miRs) have been suggested to function as important regulators of cancer. In addition, the expression of miR-140-5p is decreased in patients with NSCLC. Therefore, it is important to further elucidate the role of miR-140-5p in NSCLC. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used in order to investigate the expression of miR-140-5p in NSCLC tissues and matched normal tissues and to determine miR-140-5p levels following transfection with mimics into A549 lung cancer cells. Targetscan software was used to predict the oncogene target of miR-140-5p. This analysis revealed that YES proto-oncogene 1 (YES1) includes a target site for miR-140-5p binding. The results revealed that YES1 is a potential target gene of miR-140-5p, and this was further confirmed by the results of luciferase reporter assays, which demonstrated that miR-140-5p directly targeted the predicted binding site in the 3'-untranslated region of YES1. Cell Counting Kit-8 (CCK-8) and flow cytometry assays were performed to determine the levels of cell viability and apoptosis. Western blot assays was performed to investigate the expression levels of YES1 and proteins associated with apoptosis in A549 cells following transfection. The results revealed that miR-140-5p expression was significantly downregulated in NSCLC tissues compared with matched normal tissues. The expression of miR-140-5p was significantly increased following transfection with miR-140-5p mimics. The results of CCK-8 and flow cytometry assays indicated that miR-140-5p inhibited proliferation and induced apoptosis of tumor cells. Western blot analysis and RT-qPCR revealed that YES1 and B-cell lymphoma 2 (Bcl-2) mRNA and protein expression levels were markedly decreased in A549 cells, while Bcl-2 associated X (Bax) and caspase-3 expression levels increased significantly following transfection with miR-140-5p mimics compared with the negative control group. In conclusion, miR-140-5p may induce apoptosis in A549 cells by targeting YES1 and regulating the expression of apoptosis-associated proteins Bcl-2, Bax and caspase-3.

Prussian blue analogues derived iron-cobalt alloy embedded in nitrogen-doped porous carbon nanofibers for efficient oxygen reduction reaction in both alkaline and acidic solutions.

Exploring highly active, inexpensive and robust electrocatalysts for oxygen reduction reaction (ORR) is of great significance as a competitive alternative to noble metal-based catalysts in energy conversion and storage devices. In the present study, we design a novel ORR electrocatalyst of iron-cobalt (FeCo) alloy nanoparticles embedded on N-doped porous carbon nanofibers (FeCo@PCNF-T) by electrospinning of [Polyacrylonitrile (PAN)/Prussian blue analogues/CaCO3] and post-calcination treatment. The obtained catalysts with bimetallic active sites show unique three-dimensional (3D) hierarchical meso/macropores structures. FeCo alloy nanoparticles are encapsulated into graphitic carbon that can increase stability and provide additional catalytic active sites. Under the optimized condition, FeCo@PCNF-800 displays excellent ORR electrocatalytic activity in alkaline solutions, with a more positive half-wave potential (E1/2 of 0.854 V vs RHE) and larger limited-diffusion current density (j of 6.012 mA cm-2) than those of 20 wt% Pt/C (E1/2 of 0.849 V and j of 5.710 mA cm-2). In addition, FeCo@PCNF-800 also exhibits comparable ORR electrocatalytic activity in acidic solutions to those of 20 wt% Pt/C with onset potential and half-wave potential as more positive as 0.843 V vs RHE and 0.739 V vs RHE, respectively. Moreover, FeCo@PCNF-800 exhibits excellent tolerance towards methanol, stability and a four-electron pathway in both basic and acidic solutions. The excellent ORR electrocatalytic activity performance of FeCo@PCNF-800 is attributed to the synergistic effect of the FeCo alloy nanoparticles and N-doped porous carbon nanofibers. The synergistic effect can improve the mass and charge transport capability and increase active sites of FeCo-N-C. Furthermore, this work offers a new insight for the reasonable design and development of efficient non-noble metal electrocatalysts for challenging electrochemical energy-related technologies.

A novel enzyme-free glucose and H2O2 sensor based on 3D graphene aerogels decorated with Ni3N nanoparticles.

In this work, a novel enzyme-free glucose and hydrogen peroxide (H2O2) sensor based on Ni3N nanoparticles on conductive 3D graphene aerogels (Ni3N/GA) has been successfully synthesized by using hydrothermal reaction, freeze-dried and then calcined under NH3 atmosphere. The obtained Ni3N/GA composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), nitrogen adsorption-desorption isotherms and electrochemical methods. The results show the obtained 3D Ni3N/GA composites exhibit excellent electrochemical performance toward glucose oxidation and H2O2 reduction with larger catalytic rate constant Kcat value of 3.75 × 103 M-1 s -1 and 1.24 × 103 M-1 s -1, respectively. As a glucose sensor, the obtained electrode provides a wide detection range of 0.1-7645.3 µM, fast response time within 3 s, high sensitivity of 905.6 µA mM-1 cm-2 and low detection limit of 0.04 µM. For detection of H2O2, this prepared sensor offers a wide detection range (5 µM-75.13 mM), fast response time (within 5 s), sensitivity (101.9 µA mM-1 cm-2) and low detection limit (1.80 µM). This enzyme-free glucose and H2O2 sensor display satisfactory selectivity, reproducibility and long-term storage stability. Additionally, the sensor can also be used for glucose and H2O2 detection in human blood serum. The results demonstrate that 3D GA nanostructures provide an enviable conductive network for efficient charge transfer and avoid Ni3N nanoparticles aggregation, which is advantageous for electrocatalytic applications.

Antitumor activity of nimotuzumab in combination with cisplatin in lung cancer cell line A549 in vitro.

Nimotuzumab, a humanized IgG1 monoclonal antibody against epidermal growth factor receptor (EGFR), increases radiosensitivity in lung cancer. Cisplatin is an effective antitumor agent in lung cancer. In the present study, the antitumor activity of nimotuzumab combined with cisplatin was investigated in A549 lung cancer cells. Viability, cell cycle distribution and cyclin D1 expression were assessed following treatment with nimotuzumab alone, cisplatin alone, nimotuzumab in combination with cisplatin, and nimotuzumab followed sequentially by cisplatin. The inhibitory effect on cell viability of nimotuzumab sequentially followed by cisplatin was higher compared with cisplatin alone (82.17±1.62 vs. 56.97±1.42%). Compared with treatment by cisplatin alone, cell cycle analysis by flow cytometry demonstrated that the percentage of cells in the G0/G1 phase was increased when A549 cells were treated with nimotuzumab followed sequentially by cisplatin (P<0.01). However, the proportion of cells in G0/G1 phase was decreased when A549 cells were treated with nimotuzumab and cisplatin simultaneously compared with cisplatin alone (P<0.05). Cyclin D1 expression was decreased in all chemotherapy treatment groups; the most significant decrease was in A549 cells treated with nimotuzumab followed sequentially by cisplatin. Nimotuzumab may enhance the antitumor activity of cisplatin on A549 cells. The cell cycle arrest at G0/G1 observed may have been due to decreased cyclin D1 levels. Potential antagonism was identified when A549 cells were treated with nimotuzumab and cisplatin simultaneously, indicating that targeted therapy may be more effective when administered prior to conventional chemotherapy.

Contrastive study on porphyrinic iron metal-organic framework supported on various carbon matrices as efficient electrocatalysts.

Porphyrinic iron metal-organic framework (pFeMOF) was combined with different kinds of carbon matrices, including porous graphene (PG), ordered mesoporous carbon (OMC) and macroporous carbon (MPC) via a simple one-step hydrothermal method. The introduction of carbon substrates improves the electrical conductivity and stability of pFeMOF. The presence of carbon also reduces the size of pFeMOF crystallites, leading to more active sites. The catalysts were used to electrocatalysis of hydrogen evolution reaction (HER) and the reduction of hydrogen peroxide (H2O2). Electrochemical measurements show that pFeMOF/PG has better electrocatalytic efficiency than pFeMOF/OMC, pFeMOF/MPC and pFeMOF. The HER on pFeMOF/PG displays a small onset potential of -34.37 mV vs. reversible hydrogen electrode (RHE), a low Tafel slope of 73.06 mV dec-1, a small over-potential of 154.71 mV at 10 mA cm-2. The catalytic effect for H2O2 is also satisfied. The linearity range of H2O2 is as wide as 5-4310 µM, and the sensitivity is as high as 77.38 µA mM-1. Such splendid performances may be attributed to the crumpled structure of PG leading to evenly and smaller pFeMOF. Furthermore, abundant hierarchical pores of pFeMOF/PG result in larger electrochemically surface areas. Our work may provide a new approach to design efficient non-precious metal catalysts.

Single Flexible Janus Nanobelts to Realize Tunable and Enhanced Simultaneous Photoluminescent, Electrical, and Magnetic Trifunctionality.

Y2 O3 :Eu3+ nanoparticles (NPs), polyaniline (PANI), and Fe3 O4 NPs are incorporated into polymethyl methacrylate (PMMA) and electrospun into [Y2 O3 :Eu3+ /PMMA]//[PANI/Fe3 O4 /PMMA] Janus nanobelts with Y2 O3 :Eu3+ /PMMA as one half side and PANI/Fe3 O4 /PMMA as the other. The morphology and properties of the final products are investigated in detail by X-ray diffraction (XRD), scanning electron microscopy (SEM), optical microscopy (OM), energy-dispersive spectrometry (EDS), Hall effect measurements, fluorescence spectroscopy, vibrating sample magnetometry (VSM), and UV/Vis spectroscopy. The results reveal that the [Y2 O3 :Eu3+ /PMMA]//[PANI/Fe3 O4 /PMMA] trifunctional Janus nanobelts possess excellent electrical conductivity, magnetism, and fluorescence owing to their special nanostructure. Fluorescence emission peaks of Eu3+ are observed in the Janus nanobelts. The electrical conductivity reaches the order of 10-4  S cm-1 . The luminescent intensity, electrical conductivity, and saturation magnetization of the Janus nanobelts can be tuned by adjusting the respective amounts of Y2 O3 :Eu3+ NPs, PANI, and Fe3 O4 NPs. The flexible luminescent-electrical-magnetic trifunctional Janus nanobelts have many potential applications. More importantly, this design concept and construct technology is of universal significance for the fabrication of other multifunctional nanostructures.