Herein, a novel dual single‐atom catalyst comprising adjacent Fe‐N4 and Mn‐N4 sites on 2D ultrathin N‐doped carbon nanosheets with porous structure (FeMn‐DSAC) was constructed as the cathode for a ...flexible low‐temperature Zn‐air battery (ZAB). FeMn‐DSAC exhibits remarkable bifunctional activities for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Control experiments and density functional theory calculations reveal that the catalytic activity arises from the cooperative effect of the Fe/Mn dual‐sites aiding *OOH dissociation as well as the porous 2D nanosheet structure promoting active sits exposure and mass transfer during the reaction process. The excellent bifunctional activity of FeMn‐DSAC enables the ZAB to operate efficiently at ultra‐low temperature of −40 °C, delivering 30 mW cm−2 peak power density and retaining up to 86 % specific capacity from the room temperature counterpart.
A Fe/Mn dual single‐atom catalyst with an excellent bifunctional activity is prepared as the cathode for a flexible low‐temperature Zn‐air battery (ZAB). Profiting from the combined Fe/Mn dual‐site effect as well as the porous 2D nanosheet structure, the ZAB could operate efficiently at the ultra‐low temperature of −40 °C.
Label Enhancement for Label Distribution Learning Xu, Ning; Liu, Yun-Peng; Geng, Xin
IEEE transactions on knowledge and data engineering,
2021-April-1, 2021-4-1, Letnik:
33, Številka:
4
Journal Article
Recenzirano
Odprti dostop
Label distribution is more general than both single-label annotation and multi-label annotation. It covers a certain number of labels, representing the degree to which each label describes the ...instance. The learning process on the instances labeled by label distributions is called label distribution learning (LDL). Unfortunately, many training sets only contain simple logical labels rather than label distributions due to the difficulty of obtaining the label distributions directly. To solve this problem, one way is to recover the label distributions from the logical labels in the training set via leveraging the topological information of the feature space and the correlation among the labels. Such process of recovering label distributions from logical labels is defined as label enhancement (LE), which reinforces the supervision information in the training sets. This paper proposes a novel LE algorithm called Graph Laplacian Label Enhancement (GLLE). Experimental results on one artificial dataset and fourteen real-world LDL datasets show clear advantages of GLLE over several existing LE algorithms. Furthermore, experimental results on eleven multi-label learning datasets validate the advantage of GLLE over the state-of-the-art multi-label learning approaches.
Highly selective separation and/or purification of acetylene from various gas mixtures is a relevant and difficult challenge that currently requires costly and energy‐intensive chemisorption ...processes. Two ultramicroporous metal–organic framework physisorbents, NKMOF‐1‐M (M=Cu or Ni), offer high hydrolytic stability and benchmark selectivity towards acetylene versus several gases at ambient temperature. The performance of NKMOF‐1‐M is attributed to their exceptional acetylene binding affinity as revealed by modelling and several experimental studies: in situ single‐crystal X‐ray diffraction, FTIR, and gas mixture breakthrough tests. NKMOF‐1‐M exhibit better low‐pressure uptake than existing physisorbents and possesses the highest selectivities yet reported for C2H2/CO2 and C2H2/CH4. The performance of NKMOF‐1‐M is not driven by the same mechanism as current benchmark physisorbents that rely on pore walls lined by inorganic anions.
Ultramicroporous MOF (metal–organic framework) physisorbents, NKMOF‐1‐M (M=Cu or Ni), offer high hydrolytic stability and benchmark selectivity towards acetylene versus several gases at ambient temperature. The performance of NKMOF‐1‐M is attributed to exceptional acetylene binding affinity. NKMOF‐1‐M exhibits better low‐pressure uptake than existing physisorbents and possesses the highest selectivities yet reported for C2H2/CO2 and C2H2/CH4.
Long non-coding RNAs (lncRNAs) are essential factors that regulate tumor development and metastasis via diverse molecular mechanisms in a broad type of cancers. However, the pathological roles of ...lncRNAs in gallbladder carcinoma (GBC) remain largely unknown. Here we discovered a novel lncRNA termed lncRNA Highly expressed in GBC (lncRNA-HGBC) which was upregulated in GBC tissue and aimed to investigate its role and regulatory mechanism in the development and progression of GBC.
The expression level of lncRNA-HGBC in GBC tissue and different cell lines was determined by quantitative real-time PCR. The full length of lncRNA-HGBC was obtained by 5' and 3' rapid amplification of the cDNA ends (RACE). Cellular localization of lncRNA-HGBC was detected by fluorescence in situ hybridization (FISH) assays and subcellular fractionation assay. In vitro and in vivo assays were preformed to explore the biological effects of lncRNA-HGBC in GBC cells. RNA pull-down assay, mass spectrometry, and RNA immunoprecipitation (RIP) assay were used to identify lncRNA-HGBC-interacting proteins. Dual luciferase reporter assays, AGO2-RIP, and MS2-RIP assays were performed to verify the interaction between lncRNA-HGBC and miR-502-3p.
We found that lncRNA-HGBC was upregulated in GBC and its upregulation could predict poor survival. Overexpression or knockdown of lncRNA-HGBC in GBC cell lines resulted in increased or decreased, respectively, cell proliferation and invasion in vitro and in xenografted tumors. LncRNA-HGBC specifically bound to RNA binding protein Hu Antigen R (HuR) that in turn stabilized lncRNA-HGBC. LncRNA-HGBC functioned as a competitive endogenous RNA to bind to miR-502-3p that inhibits target gene SET. Overexpression, knockdown or mutation of lncRNA-HGBC altered the inhibitory effects of miR-502-3p on SET expression and downstream activation of AKT. Clinically, lncRNA-HGBC expression was negatively correlated with miR-502-3p, but positively correlated with SET and HuR in GBC tissue.
Our study demonstrates that lncRNA-HGBC promotes GBC metastasis via activation of the miR-502-3p-SET-AKT cascade, pointing to lncRNA-HGBC as a new prognostic predictor and a therapeutic target.
The conventional P2-type cathode material Na
0.67
Ni
0.33
Mn
0.67
O
2
suffers from an irreversible P2-O2 phase transition and serious capacity fading during cycling. Here, we successfully carry out ...magnesium and calcium ion doping into the transition-metal layers (TM layers) and the alkali-metal layers (AM layers), respectively, of Na
0.67
Ni
0.33
Mn
0.67
O
2
. Both Mg and Ca doping can reduce O-type stacking in the high-voltage region, leading to enhanced cycling endurance, however, this is associated with a decrease in capacity. The results of density functional theory (DFT) studies reveal that the introduction of Mg
2+
and Ca
2+
make high-voltage reactions (oxygen redox and Ni
4+
/Ni
3+
redox reactions) less accessible. Thanks to the synergetic effect of co-doping with Mg
2+
and Ca
2+
ions, the adverse effects on high-voltage reactions involving Ni-O bonding are limited, and the structural stability is further enhanced. The finally obtained P2-type Na
0.62
Ca
0.025
Ni
0.28
Mg
0.05
Mn
0.67
O
2
exhibits a satisfactory initial energy density of 468.2 W h kg
−1
and good capacity retention of 83% after 100 cycles at 50 mA g
−1
within the voltage range of 2.2-4.35 V. This work deepens our understanding of the specific effects of Mg
2+
and Ca
2+
dopants and provides a stability-enhancing strategy utilizing abundant alkaline earth elements.
A synergetic effect involving Mg and Ca can reduce the adverse impact on redox reactions related to Ni-O bonding in Mg and Ca co-doped P2-Na
0.67
Ni
0.33
Mn
0.66
O
2
material, leading to better overall properties than its singly-doped counterparts.
Minichromosome maintenance (MCM) proteins play important roles in DNA replication by interacting with other factors which participate in the regulation of DNA synthesis. Abnormal over-expression of ...MCMs was observed in numerous malignancies, such as colorectal cancer. However, the expression of MCMs in pancreatic cancer (PC) was less investigated so far. This study was designed to analyze the expression and prognostic roles of MCM1-10 in PC based on the data provided by The Cancer Genome Atlas (TCGA).
Pearson χ2 test was applied to evaluate the association of MCMs expression with clinicopathologic indicators, and biomarkers for tumor biological behaviors. Kaplan-Meier plots and log-rank tests were used to assess survival analysis, and univariate and multivariate Cox proportional hazard regression models were used to recognize independent prognostic factors.
MCM1-10 were generally expressed in PC samples. The levels of some molecules were markedly correlated with that of biomarkers for S phase, proliferation, gemcitabine resistance. And part of these molecules over-expression was significantly associated with indicators of disease progression, such as depth of tumor invasion and lymph node metastasis. Furthermore, MCM2, 4, 6, 8, and 10 over-expression was remarkably associated with shorter disease free survival time, and MCM2, 4,8, and 10 over-expression was associated with shorter overall survival time. Further multivariate analysis suggested that MCM8 was an independent prognostic factor for PC.
MCMs abnormal over-expression was significantly associated with PC progression and prognosis. These molecules could be regarded as prognostic and therapeutic biomarkers for PC. The roles of MCMs may be vitally important and the underlying mechanisms need to be furtherinvestigated.
Simultaneous removal of trace amounts of propyne and propadiene from propylene is an important but challenging industrial process. We report herein a class of microporous metal–organic frameworks ...(NKMOF‐1‐M) with exceptional water stability and remarkably high uptakes for both propyne and propadiene at low pressures. NKMOF‐1‐M separated a ternary propyne/propadiene/propylene (0.5 : 0.5 : 99.0) mixture with the highest reported selectivity for the production of polymer‐grade propylene (99.996 %) at ambient temperature, as attributed to its strong binding affinity for propyne and propadiene over propylene. Moreover, we were able to visualize propyne and propadiene molecules in the single‐crystal structure of NKMOF‐1‐M through a convenient approach under ambient conditions, which helped to precisely understand the binding sites and affinity for propyne and propadiene. These results provide important guidance on using ultramicroporous MOFs as physisorbent materials.
Blatant favoritism: A class of microporous water‐stable MOFs enabled the simultaneous removal of trace amounts of propyne and propadiene from propylene (see picture) to produce polymer‐grade propylene with high selectivity (99.996 %) at ambient temperature. A method for the visualization of propyne and propadiene molecules in the single‐crystal structure of the MOF helped to explain the strong binding affinity for propyne and propadiene over propylene.
Surface plasmon resonance (SPR) technology has effectively bolstered optic fiber sensing in fields of life science, clinical diagnosis, medicine, food safety and so on. The current review outlines ...the research status of fiber optic biosensor based on SPR, and the merits of optical fiber sensor and the development of optical fiber sensor based on SPR are completely covered. An in-depth review of four devices for generating SPR is presented, and optical fiber is finally adopted for a substrate to generate SPR. Different prototypes of optical fiber biosensor based on SPR are meticulously outlined: optical fiber grating biosensor based on SPR and optical fiber structured type biosensor based on SPR, and representative instances from literature are presented to verify the latest advancements in this potentially valuable research avenue. In addition, the sensing performance of different optical fiber structured type biosensor based on SPR are compared. What's more, simultaneous multi-parameter detection and improvement of sensitivity are discussed and summarized. The article concludes identify key challenges and develop orientation of optical fiber biosensor based on SPR.
•This paper reviews the research status of fiber optic biosensors based on SPR.•Firstly, the SPR generation methods are systematically summarized.•The fiber grating biosensor and the optical fiber biosensor which can produce SPR effect are analyzed.•The double or multi-parameter measurement of SPR-based optical fiber biosensor is analyzed.
•MnOx/biochar and FeOx/biochar significantly improved ozonization of ATZ.•Enhanced formation of •OH was observed in the catalytic ozonation systems.•Increased Lewis acid sites and electron transfer ...contributed for the O3 catalyzation.•Toxicity of ATZ had been largely eliminated after the heterogeneous catalytic ozonation.
After reaction with permanganate or ferrate, the resulted Mn-loaded and Fe-loaded biochar (MnOx/biochar and FeOx/biochar) exhibited excellent catalytic ozonation activity. O3 (2.5 mg/L) eliminated 48% of atrazine (ATZ, 5 μM) within 30 min at pH 7.0, while under identical conditions, ozonation efficiency of ATZ increased to 83% and 100% in MnOx/biochar and FeOx/biochar (20 mg/L) heterogeneous catalytic systems, respectively. Radical scavenger experiment and electron paramagnetic resonance (EPR) analysis confirmed that hydroxyl radical (•OH) was the dominant oxidant. Total Lewis acid sites on MnOx/biochar and FeOx/biochar were 3.5 and 4.1 times of that on the raw biochar, which induced enhanced adsorption of O3 and its subsequent decomposition into •OH. Electron transfer via redox pairs on MnOx/biochar and FeOx/biochar was observed by cyclic voltammetry scans, which also functioned in the improved catalytic capacity. Degradation pathways of ATZ in MnOx/biochar and FeOx/biochar ozonation systems were proposed, with 34.6% and 44.8% of dechlorination effect accomplished within 30 min of reaction, which was improved by 4.1 and 5.3 times compared to pure ozonation. After 12-hour treatment, acute toxicity of ATZ oxidation products was reduced from 38.3% of pure ozonation system to 14.5% and 6.3% of activated ozonation systems with MnOx/biochar and FeOx/biochar, respectively. Mn-loaded biochar and Fe-loaded biochar have great potential for heterogeneous catalytic ozonation of polluted water.
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Ammonia–borane (AB) is a promising chemical hydrogen‐storage material. However, the development of real‐time, efficient, controllable, and safe methods for hydrogen release under mild conditions is a ...challenge in the large‐scale use of hydrogen as a long‐term solution for future energy security. A new class of low‐cost catalytic system is presented that uses nanostructured Ni2P as catalyst, which exhibits excellent catalytic activity and high sustainability toward hydrolysis of ammonia–borane with the initial turnover frequency of 40.4 mol(H2) mol(Ni2P)−1 min−1 under air atmosphere and at ambient temperature. This value is higher than those reported for noble‐metal‐free catalysts, and the obtained Arrhenius activation energy (Ea=44.6 kJ mol−1) for the hydrolysis reaction is comparable to Ru‐based bimetallic catalysts. A clearly mechanistic analysis of the hydrolytic reaction of AB based on experimental results and a density functional theory calculation is presented.
A low‐cost catalytic system using nanostructured Ni2P as the catalyst was established for the hydrolysis of ammonia–borane. This system exhibits excellent catalytic activity and high sustainability under an air atmosphere and at ambient temperature.
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