The NH3-SCR technology, based on CeO2-MnOx catalysts, is of great significance for NOx removal at low temperatures. Microwave irradiation, as an effective heating approach, can enhance the ...low-temperature NH3-SCR activity of catalysts. Herein, the structure-activity relationship of CeO2-MnOx oxides catalysts was explored under microwave irradiation. The MnOx catalyst and Ce-Mn(1:1) mixed oxide catalyst exhibited good low-temperature de-NOx performance in the microwave field. With the increase of microwave irradiation intensity and time, the structure and phase composition of MnOx material underwent significant changes. CeO2 played a key role in maintaining the structural stability of the Ce-Mn(1:1) catalyst. In addition, microwave irradiation affected the redox properties and acidity of the catalyst, regulating the catalytic performance. Suitable microwave operation conditions were conducive to increasing the number of acidic sites and enhancing the redox properties, which improved the low-temperature catalytic activity of the catalyst.
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•The structure-activity relationship of the CeO2-MnOx oxides catalysts was explored under microwave irradiation.•The Mn-based catalysts showed a good microwave absorption ability, inducing the variation of phase and structure.•CeO2 played a key role in maintaining the structural stability of the Ce-Mn(1:1) catalyst.•Microwave irradiation affected the acidity and redox properties of the catalysts, regulating the catalystic activity.
Numerous nanomaterials have been utilized for novel biosensors with sensitivity and selectivity in the last decades due to their intrinsic unique properties. Herein, a facile fluorescence method for ...nucleic acid detection was developed by employing TiO2 nanowires (NWs) as the sensing platform. The quenching effect of TiO2 NWs to fluorophore-labelled single-stranded DNA (ssDNA) was found to be more significant than that to fluorophore-labelled double-stranded DNA (dsDNA) or triplex DNA probes. More importantly, the whole quenching process was also fast since it just took about ten minutes to reach the equilibrium. Based on the different affinities of TiO2 NWs to ssDNA, dsDNA and triplex DNA probes, the sequence-specific nucleic acids were detected with sensitivity and specificity. Further investigation has demonstrated that the quenching efficiency of TiO2 NWs to long ssDNA was apparently superior than that to short ssDNA. Moreover, the fluorescence from various ssDNA probes labelled with a wide spectrum of fluorescent dyes could also be quenched by TiO2 NWs. These inspiring results reveal that TiO2 NWs could be an excellent universal nanoquencher used in the next-generation biosensors.
A facile fluorescence method was developed for sequence-specific single- and double-stranded DNA detection by using TiO2 nanowires as a nanoquencher. Display omitted
•Excellent quenching ability of TiO2 nanowires to dye-labelled single-stranded DNA probes was demonstrated.•The TiO2 nanowire-based sensing platform could be used for nucleic acid assay with high sensitivity and selectivity.•The nucleic acid sensing platform based on TiO2 nanowires was simple and fast.
To construct a recombinant human adenovirus type 5 (Ad5) expressing luciferase and GFP reporter gene and detect neutralizing antibodies against adenovirus type 5 in common marmosets (Callithrix ...jacchus) to provide basic laboratory data for evaluating adenovirus vaccines.
Luciferase and GFP reporter genes from plasmid pHAGE-CMV-GFP were inserted into pDC315 to construct the recombinant adenovirus shutter plasmid pDC315-Luc-GFP. The shutter plasmid was co-transduced with pBHGlox(delta)E1,3Cre in 293A cell line to package the recombinant adenovirus rAd5/Luc/GFP. Three rounds of plaque formation experiment were performed to select the monoclonal adenovirus followed by purification with cesium chloride density gradient centrifugation and virus titration with TCID50 method. Chemiluminescence assay and flow cytometry were employed to detect the neutralizing antibody levels in 14 common marmosets.
The shuttle plasmid pDC315-Luc-GFP was successfully constructed and the recombinant adenovirus rAd5/Luc/GFP was packaged
Endothelin1 (ET1) is a potent vasoconstrictor that is also known to be a neuropeptide that is involved in neural circuits. We examined the role of ET1 that has been implicated in the anxiogenic ...process. We found that infusing ET1 into the IL cortex increased anxiety-like behaviors. The ET
A
receptor (ET
A
R) antagonist (BQ123) but not the ET
B
receptor (ET
B
R) antagonist (BQ788) alleviated ET1-induced anxiety. ET1 had no effect on GABAergic neurotransmission or NMDA receptor (NMDAR)-mediated neurotransmission, but increased AMPA receptor (AMPAR)-mediated excitatory synaptic transmission. The changes in AMPAR-mediated excitatory postsynaptic currents were due to presynaptic mechanisms. Finally, we found that the AMPAR antagonists (CNQX) and BQ123 reversed ET1’s anxiogenic effect, with parallel and corresponding electrophysiological changes. Moreover, infusing CNQX + BQ123 into the IL had no additional anxiolytic effect compared to CNQX treatment alone. Altogether, our findings establish a previously unknown anxiogenic action of ET1 in the IL cortex. AMPAR-mediated glutamatergic neurotransmission may underlie the mechanism of ET1-ET
A
R signaling pathway in the regulation of anxiety.
The local discontinuous Galerkin (LDG) method is studied for a third-order singularly perturbed problem of convection-diffusion type.
Based on a regularity assumption for the exact solution, we prove ...almost
(up to a logarithmic factor) energy-norm convergence uniformly in the perturbation parameter.
Here,
is the maximum degree of piecewise polynomials
used in discrete space, and
is the number of mesh elements.
The results are valid for the three types of layer-adapted meshes:
Shishkin-type, Bakhvalov–Shishkin-type, and Bakhvalov-type.
Numerical experiments are conducted to test the theoretical results.
•A high accuracy fault diagnosis scheme for harmonic reducer practical application scenarios is proposed.•Dynamic rules for harmonic reducer in dynamic operating conditions are quantifiably ...expressed.•Behavioral model is constructed based on the mapping relationship between external excitation and monitoring signals.•The interpretability of Hidden Markov Model in fault diagnosis application is improved.
Harmonic reducer is a critical and vulnerable component of industrial robots. Its dynamic rules are difficult to express because harmonic reducers always operate under continuously varying operating conditions in practical application scenarios. How to achieve fault diagnosis under dynamic operating parameters is a challenge. This paper proposes a fault diagnosis scheme for harmonic reducer under practical operating conditions. Hidden Markov Model is used to depict the dynamic rules, novel features state transition probability and observation probability are extracted to construct the mapping relationship between external excitation and monitoring signals. A CNN framework is employed for fault recognition based on fault impacts on the mapping relationship. The results of the verification experiment show that the scheme can achieve high accuracy fault diagnosis in dynamic operating conditions by fully utilizing Hidden Markov Model. The mapping relationship can serve as a behavioral model to support digital-twin modeling and health management for industrial robots.
In this article, we synthesized a Yb
-doped two-dimensional (2-D) upconverting Tb metal-organic framework (Tb-MOF) (hereinafter referred to as Tb-UCMOF) by a one-step solvothermal method. The ...synthesized Tb-UCMOF is composed of stacks of 2-D nanosheets with an average width distributed between 250 and 300 nm, and these nanosheets can be exfoliated by a simple liquid ultrasound method. The structural characteristics of this flaky particle accumulation are confirmed by the type IV adsorption-desorption isotherm with a H
-type adsorption hysteresis loop, and the Brunauer-Emmett-Teller surface of Tb-UCMOF is 143.9257 m
·g
. Tb-UCMOF has characteristic emissions of Tb
which are located at 490, 545, 585, and 621 nm under 980 nm excitation. The upconverting luminescence mechanism is attributed to that Yb
absorbs multiple photons and transfers the energy to Tb
, causing its 4f electrons to jump to the excited state, and then the upconverting emissions are obtained when electrons return to the ground state. Since the Tb-UCMOF nanosheets have high dispersibility and an obvious upconverting luminescent signal, we explored their luminescence sensing properties. The luminescence intensity is found to gradually decrease with the addition of Cu
, the linear range of Cu
sensing is 0-1.4 μM, and the detection limit is 0.16 μM. This rapid, highly selective, and sensitive Cu
sensing indicates that 2-D upconverting MOF nanosheets have great application prospects in luminescence sensing and also promote the research of 2-D upconverting MOFs with specific recognition for the application of biological and environmental luminescent sensors.
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