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•The GSEC films were electrochemical activated in KOH solution with CV.•The electrochemical activation mechanisms of GSEC in alkaline solution were clarified.•Activation caused more ...defective graphene edges and carbonyl functional formation.•Activation greatly improved the electrochemical activity of GSEC film.•Activated GSEC film could be applied in simultaneous detecting HQ, CC and RC sensitivity.
In this study, the graphene sheets embedded carbon (GSEC) film was electrochemically activated in KOH solution for high sensitivity simultaneous determination of hydroquinone (HQ), catechol (CC) and resorcinol (RC). The electrochemical activation mechanism of GSEC films in alkaline solution was clarified. We found that the embedded graphene sheets were corroded during activation, resulting in the formation of more defective graphene edges and carbonyl functional groups at the surface of carbon film. These corroded graphene edges provided more electrochemical active sites and accelerated the electron transfer. Thus, the activated GSEC film exhibited highly electrocatalytic activity towards the oxidation of HQ, CC and RC. The redox peak separation for HQ and CC decreased from 366 mV to 62 mV and 262 mV to 54 mV, respectively. The oxidation potential of RC also decreased from 714 mV to 590 mV. The electrochemical sensor showed a wide liner response for HQ, CC and RC in the concentration range of 0.5∼200 μM, 0.5∼200 μM and 0.2∼400 μM with detection limit of 0.1 μM, 0.1 μM and 0.05 μM, respectively. These results demonstrate that the KOH-activated GSEC film is a promising electrode material for constructing highly sensitive and selective biosensors.
The design of high‐efficiency non‐noble bifunctional electrocatalysts for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is paramount for water splitting technologies and ...associated renewable energy systems. Spinel‐structured oxides with rich redox properties can serve as alternative low‐cost OER electrocatalysts but with poor HER performance. Here, zirconium regulation in 3D CoFe2O4 (CoFeZr oxides) nanosheets on nickel foam, as a novel strategy inducing bifunctionality toward OER and HER for overall water splitting, is reported. It is found that the incorporation of Zr into CoFe2O4 can tune the nanosheet morphology and electronic structure around the Co and Fe sites for optimizing adsorption energies, thus effectively enhancing the intrinsic activity of active sites. The as‐synthesized 3D CoFeZr oxide nanosheet exhibits high OER activity with small overpotential, low Tafel slope, and good stability. Moreover, it shows unprecedented HER activity with a small overpotential of 104 mV at 10 mA cm−2 in alkaline media, which is better than ever reported counterparts. When employing the CoFeZr oxides nanosheets as both anode and cathode catalysts for overall water splitting, a current density of 10 mA cm−2 is achieved at the cell voltage of 1.63 V in 1.0 m KOH.
CoFe2O4 after incorporation of zirconium tunes the nanosheet morphology and electronic structure around the Co and Fe sites for optimizing the adsorption energies, thus effectively enhancing the intrinsic activity of the active sites. Thus, the as‐synthesized optimal electrocatalyst of 3D zirconium‐regulated CoFe2O4 (CoFeZr oxides) nanosheets exhibits superior bifunctional OER and HER activities for overall water splitting.
Broomcorn millet (Panicum miliaceum L.) has strong tolerance to abiotic stresses, and is probably one of the oldest crops, with its earliest cultivation that dated back to ca. ~10,000 years. We ...report here its genome assembly through a combination of PacBio sequencing, BioNano, and Hi-C (in vivo) mapping. The 18 super scaffolds cover ~95.6% of the estimated genome (~887.8 Mb). There are 63,671 protein-coding genes annotated in this tetraploid genome. About ~86.2% of the syntenic genes in foxtail millet have two homologous copies in broomcorn millet, indicating rare gene loss after tetraploidization in broomcorn millet. Phylogenetic analysis reveals that broomcorn millet and foxtail millet diverged around ~13.1 Million years ago (Mya), while the lineage specific tetraploidization of broomcorn millet may be happened within ~5.91 million years. The genome is not only beneficial for the genome assisted breeding of broomcorn millet, but also an important resource for other Panicum species.
The liver is a common site for the development of primary (i.e., originating from the liver, e.g., hepatocellular carcinoma) or secondary (i.e., spread to the liver, e.g., colorectal cancer) tumor. ...Due to its complex background, heterogeneous, and diffusive shape, automatic segmentation of tumor remains a challenging task. So far, only the interactive method has been adopted to obtain the acceptable segmentation results of a liver tumor. In this paper, we design an Attention Hybrid Connection Network architecture which combines soft and hard attention mechanism and long and short skip connections. We also propose a cascade network based on the liver localization network, liver segmentation network, and tumor segmentation network to cope with this challenge. Simultaneously, the joint dice loss function is proposed to train the liver localization network to obtain the accurate 3D liver bounding box, and the focal binary cross entropy is used as a loss function to fine-tune the tumor segmentation network for detecting more potentially malignant tumor and reduce false positives. Our framework is trained using the 110 cases in the LiTS dataset and extensively evaluated by the 20 cases in the 3DIRCADb dataset and the 117 cases in the Clinical dataset, which indicates that the proposed method can achieve faster network convergence and accurate semantic segmentation and further demonstrate that the proposed method has a good clinical value.
Oxygen evolution reactions (OERs) as core components of energy conversion and storage technology systems, such as water splitting and rechargeable metal–air batteries, have attracted considerable ...attention in recent years. Transition metal compounds, particularly layered double hydroxides (LDHs), are considered as the most promising electrocatalysts owing to their unique two-dimensional layer structures and tunable components. However, heir poor intrinsic electrical conductivities and the limited number of active sites hinder their performances. The regulation of the electronic structure is an effective approach to improve the OER activity of LDHs, including cationic and anionic regulation, defect engineering, regulation of intercalated anions, and surface modifications. In this review, we summarize recent advances in the regulation of the electronic structures of LDHs used as electrocatalysts in OERs. In addition, we discuss the effects of each regulation type on OER activities. This review is expected to shed light on the development and design of effective OER electrocatalysts by summarizing various electronic structure regulation pathways and the effects on their catalytic performances.
A review summarized recent advances in electronic structure regulations, including cationic regulation, anionic regulation, defect engineering, intercalated anions regulating, surface modifications, on LDHs as electrocatalysts for OER. Schematic summarizing the recent advances in electronic structure regulation, including cationic regulation, anionic regulation, defect engineering, intercalated anion regulation, and surface modifications on LDHs as electrocatalysts for OER.
The interfacial properties of ZnO nanowire (NW)/carbon fiber-reinforced epoxy composites are investigated using molecular dynamics (MD) simulations. An atomistic representative volume element (RVE) ...is developed in which a single ZnO NW is aligned on carbon fiber and embedded in the cross-linked epoxy. Effects of ZnO NWs on the fiber–matrix adhesion are studied by evaluating the fiber and the enhanced matrix interaction. The traction-separation behavior in both sliding mode (shear separation) and opening mode (normal separation) is evaluated. The cohesive parameters, including the peak traction and adhesion energy, are calculated in each mode. Different numbers of cross-linked epoxy units in the system are studied and validated. The interfacial properties of the hybrid system are compared with the simulated bare RVE containing fiber and epoxy. MD results showed that the interfacial strength is increased from 485 MPa to 1066 MPa with the ZnO NWs. The adhesion energy in both opening and sliding modes is significantly improved by growing ZnO NWs on the carbon fibers. In addition, the hybrid system shows more rate-independent behavior compared with the bare system in the opening mode.
Long-range chromatin interactions are important for transcriptional regulation of genes, many of which are related to complex agronomics traits. However, the pattern of three-dimensional chromatin ...interactions remains unclear in plants. Here we report the generation of chromatin interaction analysis by paired-end tag sequencing (ChIA-PET) data and the construction of extensive H3K4me3- and H3K27ac-centered chromatin interaction maps in maize. Results show that the interacting patterns between proximal and distal regulatory regions of genes are highly complex and dynamic. Genes with chromatin interactions have higher expression levels than those without interactions. Genes with proximal-proximal interactions prefer to be transcriptionally coordinated. Tissue-specific proximal-distal interactions are associated with tissue-specific expression of genes. Interactions between proximal and distal regulatory regions further interweave into organized network communities that are enriched in specific biological functions. The high-resolution chromatin interaction maps will help to understand the transcription regulation of genes associated with complex agronomic traits of maize.
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•N-doping decreased the size of graphene sheets.•N-doped graphene sheets were formed in carbon film.•N-doped graphene sheets induced high electrochemical activity.
In this study, we ...prepared a carbon film with clearly shaped N-doped graphene sheets by electron cyclotron resonance (ECR) plasma sputtering under low-energy electron irradiation. We found the N-doped graphene sheets remarkably improved the electrochemical activity of carbon film. The charge-transfer resistance was decreased from 21.62 Ω cm2 to 1.37 Ω cm2, and the redox peak separation was reduced to a low value of 65.4 mV in Fe(CN)64−/3− redox system. The high electrochemical activity of N-doped graphene sheets embedded carbon (N-GSEC) films was ascribed to the formation of smaller sized N-doped graphene sheets. The smaller sized N-doped graphene sheets with high electronic density of states produced abundant edge defects, which served as active sites, facilitated the adsorption of Fe(CN)64−/3− on film surface and enhanced the electron transfer. In detecting DNA base of adenine, the N-GSEC film showed a low oxidation potential and high sensitivity. These results demonstrate the N-GSEC film is a promising candidate material for construction sensitivity electrochemical biosensor.
We found that nanosized graphene sheets induced high electrochemical activity in pure carbon films, which prepared by electron cyclotron resonance (ECR) plasma sputtering under low-energy electron ...irradiation condition. The electrochemical properties were studied by electrochemical impedance spectroscopy and cyclic voltammetry. The graphene sheets embedded carbon (GSEC) films showed a wide potential window over 3.2 V. The charge transfer resistance and the oxidation-reduction peak separation (ΔEP) of the GSEC films are lower than amorphous carbon films in several redox systems (Fe(CN)64−/3-, Ru(NH3)62+/3+, dopamine and ascorbic acid), especially in the inner-sphere system, the ΔEP is only half of amorphous carbon films. The high electrochemical activity of GSEC films originated from the nanosized graphene sheets, which offered faster electron transfer path and more reaction active sites. Our results indicate the GSEC films have great potential to be an electrochemical biosensor in detecting biomolecules with high oxidation potential.
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•The electrochemical corrosion of N-GSEC films were investigated.•The electrochemical corrosion mechanisms of N-GSEC were clarified.•The sp2-hybridized carbon was more susceptible to ...be oxidized.•Corrosion resulted in the formation of N-doped graphene oxides.•Corrosion increased the electron transfer rates of N-GSEC film.
Electrochemical corrosion behaviors of N-doped graphene sheets embedded carbon (N-GSEC) film in H2SO4 solutions were investigated. We found that the corrosion of N-GSEC film originated from the oxidation of carbon, and the sp2-hybridized carbon was more susceptible to be oxidized than the sp3-hybridized carbon. The corrosion resulted in the formation of N-doped graphene oxides and more exposed graphene edges, which highly improved the electron transfer rates as well as the electrochemical activity of N-GSEC films. The corroded N-GSEC exhibited much higher electrocatalytic activity for phenol biomolecules. These findings shed light on the surface functional modification and application of N-GSEC films.
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