Underpotential deposition offers a predominant way to tailor the electronic structure of the catalytic surface at the atomic level, which is key to engineering materials with a high activity for ...(electro)catalysis. However, it remains challenging to precisely control and directly probe the underpotential deposition of a (sub)monolayer of atoms on nanoparticle surfaces. In this work, we in situ observe silver electrodeposited on gold nanocrystals surface from sub-monolayer to one monolayer by designing a highly sensitive electrochemical dark field scattering setup. The spectral variation is used to reconstruct the optical "cyclic voltammogram" of every single nanocrystal for understanding the underpotential deposition process on nanocrystals, which cannot be achieved by any other methods but are essential for creating novel nanomaterials.
Nanoscale zerovalent iron (nZVI) represents a promising reduction technology for water remediation, but its broad application is largely hampered by the tendency of nZVI to aggregate and the low ...electron transferability due to the interfacial charge resistance. Herein, by combining the advantages of polypyrrole (PPY) and nZVI, we prepared a composite material (i.e., PPY supported palladium‑iron bimetallic nanoparticles (Pd/Fe@PPY)) and applied it for the simultaneous removal of 4-chlorophenol (4-CP) and Cr(VI). Our results showed that this material had superior catalytic performances with a complete removal of 4-CP (50 mg·L−1) and Cr(VI) (10 mg·L−1) within 60 and 1 min, respectively. As opposed to the bare Pd/Fe nanoparticles, the reactivity of Pd/Fe@PPY with 4-CP was significantly enhanced by nearly 8 times. The enhanced catalytic activity of Pd/Fe@PPY was attributed to the distinctive properties of PPY as i) a good support that resulted in the formation of Pd/Fe nanoparticles with high dispersibility; ii) an adsorbent that increased the accessibility of 4-CP and Cr(VI) with electrons or active species (e.g., H*) on the particles surface; iii) an electron transfer carrier that facilitated the reactivity of Pd/Fe@PPY with contaminants by reducing the interfacial charge resistance. Moreover, by conducting cyclic voltammetry and quenching investigations, we showed that two mechanisms (i.e., direct and H*-mediated indirect electron transfer) were involved in the reductive dehalogenation of 4-CP, while catalytic hydrodechlorination played a dominant role. This work offers an alternative material for the efficient removal of 4-CP and Cr(VI) and provides better understanding of the relationship between structure and catalytic activity of nZVI.
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•A composite material of polypyrrole-supported Pd/Fe nanoparticles is prepared.•Enhanced catalytic ability for simultaneous 4-CP and Cr(VI) removal is reported.•A complete removal of 4-CP and Cr(VI) is efficiently achieved.•Catalytic activity is due to PPY as support, adsorbent, electron transfer carrier.•Simultaneous occurrence of direct and indirect electron transfer routes is reported.
The Yinggehai Basin (YB) in the northwest of the South China Sea (SCS) has preserved the complete evolution of the Red River Fault (RRF), whose motion over time has largely contributed to shaping the ...current tectonic framework of the southeastern Tibetan Plateau and Indochina Block. Here we, for the first time, image the RRF, crustal architecture, and crust‐mantle boundary (i.e., Moho) in detail under the YB from two high‐resolution 40‐km‐depth seismic reflection pre‐stack migration profiles. Our seismic reflection images provide direct seismic evidence to support a deep‐penetrating RRF, most likely crosscutting the Moho. In this sense, the RRF was a large‐scale shear zone, along with the clockwise rotation of the Indochina Block, to accommodate the Indochina Block extrusion during Oligocene‐early Miocene and form the YB. We highlight that the material extrusion along deep‐penetrating faults dominated the Tibetan Plateau deformation in response to the India‐Asia collision at an early stage.
Plain Language Summary
The India‐Asia collision has not only created the highest Tibetan Plateau but also resulted in material extrusion outward along multiple large‐scale strike‐slip faults. The Red River Fault (RRF) is suggested to be one of these large‐scale strike‐slip faults. The geometry and deep extension of these strike‐slip faults are fundamental to understanding the manner of the material extrusion. Despite many studies describing geophysical and geological observations of the RRF, its nature in response to the India‐Asia collision remains unknown. The Yinggehai Basin (YB) northwest of the South China Sea with >10 km thick sedimentary has preserved complete evolution of the RRF. In this study, we use high‐resolution deep seismic reflection data with a depth of 40 km, for the first time, to map the crustal architecture, detailed geometries of the crust‐mantle boundary (i.e., Moho) and the RRF under the YB. The seismic reflection images indicate that the RRF is a deep‐penetrating fault that could serve as a large‐scale shear zone. We further highlight that the RRF played a vital role in moving the Indochina Block away from the Tibetan Plateau in response to the India‐Asia collision at an early stage, and subsequently stretching and thinning the continent, eventually forming the YB.
Key Points
For the first time, we image a reflected Moho cut by the Red River Fault (RRF) structure under the Yinggehai Basin (YB), South China Sea
The RRF in the YB is inferred to be a deep‐penetrating fault, most likely cutting through the Moho boundary
The RRF was inferred to be a large‐scale shear zone accommodating the Indochina Block extrusion during Oligocene‐early Miocene
With a wind-thermal-bundled power system (WTBPS) under high wind penetration levels, the sharp power fluctuations of tie-lines for interconnected grids trigger a significant challenge of ...security-constrained power system operation. Smoothing power fluctuations with economic dispatch is widely concerned against this challenge. In this paper, an appropriate look-ahead economic dispatch framework for WTBPS considering the variable ramp rate of retrofitted coal-fired units and the flexible load transfer strategy (LTS) in high voltage distribution networks (HVDNs) is proposed. To cope with this issue, i ) we derive a new family of tightened ramping constraints of retrofitted coal-fired units in the linear and second-order conic (SOC) forms, respectively. ii ) Using graph characterization of typical HVDNs, the simplified voltage-constrained LTS via topological structures can be developed. This proposed look-ahead economic dispatch model is cast as a mixed-integer second-order cone programming (MISOCP) problem, which can be reformulated by Multi-cut Generalized Benders Decomposition (MGBD). This MGBD enables multiple sub-problems can be solved in parallel and accelerates the solving process. Finally, simulation results of a large-scale practical system validate the computational accuracy and efficiency of the proposed approach.
Core complex type structures are common in continental margins. Recent studies have proposed exhumation of deeper crustal and mantle levels during extension of the continental margin along the ...Northern South China Sea (NSCS) in a core complex mode. Here, we present high‐resolution seismic profiles across different sections of the NSCS that allow us to observe two types of core complex systems. The Kaiping Rift and eastern Baiyun Rift are characterized by a sub‐horizontal Moho and exhumation of ductile deeper crust beneath an extremely thinned brittle upper crust. The central Baiyun Rift in contrast is marked by homogeneous thinning of the entire crust that is floored by mantle unroofing with a concave‐down Moho geometry. While the former type, referred to as crustal core complexes, coincides with relatively intense syn‐rift magmatism, the latter, referred to as mantle core complexes, is marked by limited magmatism. Consistently, basin subsidence rates are lower over crustal core complexes than mantle core complexes. Compared to mantle core complexes at the magma‐poor Iberian margin, the widely distributed crustal core complexes in the NSCS indicate higher geotherms and more intense magmatism during extension of the continental lithosphere. We propose that the continental core complexes observed at the NSCS represent a typical outcome of extension of a gravitationally unstable lithosphere.
Key Points
Crustal and mantle core complexes are present in the northern margin of the South China Sea
Different core complexes exhibit discrepancies in crustal thinning processes and basin subsidence
Core complex evolution is controlled by the inherited state of the mantle lithosphere
Background and aimsGastric intestinal metaplasia (IM) is common in the gastric epithelium of patients with chronic atrophic gastritis. CDX2 activation in IM is driven by reflux of bile acids and ...following chronic inflammation. But the mechanism underlying how bile acids activate CDX2 in gastric epithelium has not been fully explored.MethodsWe performed microRNA (miRNA) and messenger RNA (mRNA) profiling using microarray in cells treated with bile acids. Data integration of the miRNA/mRNA profiles with gene ontology (GO) analysis and bioinformatics was performed to detect potential miRNA-mRNA regulatory circuits. Transfection of gastric cancer cell lines with miRNA mimics and inhibitors was used to evaluate their effects on the expression of candidate targets and functions. Immunohistochemistry and in situhybridisation were used to detect the expression of selected miRNAs and their targets in IM tissue microarrays.ResultsWe demonstrate a bile acids-triggered pathway involving upregulation of miR-92a-1–5p and suppression of its target FOXD1 in gastric cells. We first found that miR-92a-1–5p was increased in IM tissues and induced by bile acids. Moreover, miR-92a-1–5p was found to activate CDX2 and downstream intestinal markers by targeting FOXD1/FOXJ1 axis and modulating activation of nuclear factor kappa B (NF-κB) pathway. Furthermore, these effects were found to be clinical relevant, as high miR-92a-1–5p levels were correlated with low FOXD1 levels and high CDX2 levels in IM tissues.ConclusionThese findings suggest a miR-92a-1–5p/FOXD1/NF-κB/CDX2 regulatory axis plays key roles in the generation of IM phenotype from gastric cells. Suppression of miR-92a-1–5p and restoration of FOXD1 may be a preventive approach for gastric IM in patients with bile regurgitation.
We propose and experimentally demonstrate a compatible physical-layer secure optical communication (PLSOC) system that integrates self-adaptive physical-layer key distribution (PLKD) and encryption ...(PLE) in optical coherent communication. Based on bit error rate difference of QAM signals mapped by asymmetric basis state Y-00 protocol, the secret key can be secretly exchanged over public fiber links without the pre-shared keys. Moreover, we perform a parameter self-adaptive strategy for practical and dynamic PLKD. The security of the key is evaluated in the case of a fiber-tapping attack. A secure hash algorithm, SHA3-512, is used to perform privacy amplification to obtain the virtually secure key. An error-free PLKD rate reaches 39.3 Kbits/s over 300 km ultra-low loss fiber. We experimentally enable the integration of the proposed PLKD scheme and quantum noise stream cipher (QNSC) with a single wavelength, same system. Q factor penalty of the integration system compared to the QNSC system is 3.7 dB (optical back-to-back) and 4.8 dB (300 km) respectively. By exploiting a common hardware platform, with the same wavelength, the proposed PLSOC system addresses the problem that PLKD and PLE are separately performed through independent optical fiber links or wavelengths. Since only digital signal processing is used, the scheme does not require extra hardware.
Although it is generally accepted that the South China Sea margin can be classified as a magma-poor rifted margin, little is known about the structural style of the distal margin and how the distal ...deep basins evolved. Observations and data from the Northern South China Sea margin suggest that the deepwater basins (distal margin domain) are commonly underlain by a highly extended continental crust, and detachment fault systems have been interpreted in places. We have interpreted a large seismic data set covering deepwater basins in the Northern South China Sea. The interpreted Moho on reflection seismic profiles indicates that the crustal thickness varies along sections perpendicular to the coast, which is the first-order criterion to divide the whole margin into a proximal domain, necking zone and distal domain. Furthermore, the underlying extremely stretched crust (<10 km) is always accompanied by obvious fault reflections with shallow dips and large-scale sedimentary basins. One major achievement of our study is the relationships between these detachment faults and rifted basins. By integrating well data and published bathymetry data, we built the tectono-stratigraphy framework and mapped the distribution of these detachment faults. From the Qiongdongnan basin, Heshan sag, and Baiyun sag, a complex polyphase evolution can be identified. Generally, the overall evolution of these supradetachment basins can be divided into three phases. Initial rifting, which is characterized by distributed, limited-offset faulting with grabens or half-grabens bounded by steeply dipping faults. Later, focused deformation occurred in the form of detachment faulting with large horizontal displacement and large subsidence. During this phase, the intense rotation of the detachment faults is responsible for the intra-rifting unconformities and tilted block (Heshan Sag). Finally, the occurrence of sag sequences in the basins suggests likely deformation migration oceanward, as described in recent numerical modeling studies.
•The detachment faults, tilted fault blocks and thinned continental crust are interpreted based on the 2D and 3D seismic data.•Analysis of the tectono-stratigraphic framework in the distal margin reveal the development of the supra-detachment basin.•The northern South China Sea is divided into the proximal domain; the necking zone; the distal margin.
BackgroundGiven the fat redistribution in later stages of life, how the associations between abdominal obesity and the risk of morbidity and mortality have changed with age have not been elucidated, ...especially for waist to height ratio (WHtR).ObjectiveTo compare the strength of association between obesity indices and chronic diseases at baseline, and the subsequent mortality risk among US adults.MethodsWe included 21 109 participants from National Health and Nutrition Examination Survey 1999–2014. We performed logistic regression and receiver operating curve analysis to examine the discriminatory power of obesity indicators on cardiometabolic diseases and cancer at baseline. Sex-stratified and age-stratified Cox models were constructed to explore the prospective association between obesity indices and all-cause, cardiovascular and cancer mortality.ResultsElevated WHtR, elevated waist circumference (WC) and body mass index (BMI)-classified obesity are associated with higher odds of hypertension (OR: 1.37-2.13), dyslipidemia (OR: 1.06 to 1.75, all p<0.05) and diabetes (OR: 1.40-3.16, all p<0.05). WHtR had significantly better discriminatory power to predict cardiometabolic health than BMI, especially for diabetes (area under the curve: 0.709 vs 0.654). After multivariable adjustment, all obesity indicators are associated with lower risk of all-cause mortality among females aged ≥65 years (HR: 0.64 to 0.85), but the association was only significant for BMI when obesity indicators were mutually adjusted (HR: 0.79).ConclusionsWHtR and WC appeared to be the better indicators for cardiometabolic health than BMI. However, BMI had a stronger and inverse association with a greater risk of all-cause mortality among older females.
Importin α has been described as a nuclear protein transport receptor that enables proteins synthesized in the cytoplasm to translocate into the nucleus. Besides its function in nuclear transport, an ...increasing number of studies have examined its non‐nuclear transport functions. In both nuclear transport and non‐nuclear transport, a functional domain called the IBB domain (importin β binding domain) plays a key role in regulating importin α behavior, and is a common interacting domain for multiple binding partners. However, it is not yet fully understood how the IBB domain interacts with multiple binding partners, which leads to the switching of importin α function. In this study, we have distinguished the location and propensities of amino acids important for each function of the importin α IBB domain by mapping the biochemical/physicochemical propensities of evolutionarily conserved amino acids of the IBB domain onto the structure associated with each function. We found important residues that are universally conserved for IBB functions across species and family members, in addition to those previously known, as well as residues that are presumed to be responsible for the differences in complex‐forming ability among family members and for functional switching.
In this study, we have distinguished the location and propensities of amino acids important for each function of the importin α IBB domain by mapping the biochemical/physicochemical propensities of evolutionarily conserved amino acids of the IBB domain onto the structure associated with each function. We found important residues that are universally conserved for IBB functions across species and family members, in addition to those previously known, as well as residues that are presumed to be responsible for the differences in complex‐forming ability among family members and for functional switching.
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