The 2021 Maduo earthquake ruptured a 150 km‐long left‐lateral fault in the northeast Tibet. We used Synthetic Aperture Radar data collected by the Sentinel‐1A/B satellites within days of the ...earthquake to derive a finite fault model and investigate the details of slip distribution with depth. We generated coseismic interferograms and pixel offsets from different look directions corresponding to the ascending and descending satellite orbits. At the eastern end the rupture bifurcated into two sub‐parallel strands, with larger slip on the northern strand. Inversions of coseismic displacements show maximum slip to the east of the epicenter. The averaged coseismic slip has a peak at depth of 3–4 km, similar to slip distributions of a number of shallow strike‐slip earthquakes. Postseismic observations over several weeks following the Maduo earthquake reveal surface slip with amplitude up to 0.1 m that at least partially eliminated the coseismic slip deficit in the uppermost crust.
Plain Language Summary
A large earthquake occurred in a remote area of north‐east Tibet (Qinghai Province, China) on May 21, 2021. The earthquake produced a 150 km‐long rupture with surface offsets up to several meters. We used data collected by orbiting satellites to map motions of the Earth's surface that occurred during and shortly after the earthquake. The measured surface displacements were used to constrain the rupture geometry and slip distribution at depth. Best‐fitting models suggest that rupture occurred on a sub‐vertical fault steeply dipping to the north, with most of slip occurring to the east of the earthquake epicenter. The maximum coseismic slip occurred in the uppermost crust, in the depth interval of 3–4 km below the Earth's surface. A decrease in the fault offsets toward the Earth's surface is likely caused by an increased frictional resistance of the shallow layer to rapid coseismic slip. Satellite observations made in the first month after the earthquake reveal that the shallow part of the fault is slowly catching up with a deeper part to make up for the difference in the amount of slip produced during the earthquake.
Key Points
We use Sentinel‐1 Synthetic Aperture Radar data to derive a finite fault model for the 2021 M7.4 Maduo (Qinghai, China) earthquake
The along‐strike averaged coseismic slip has a maximum at depth of 3–4 km, with an amplitude of ∼2.5 m
Up to 0.1 m of afterslip occurred on the fault trace in the first month following the earthquake
Ir‐based binary and ternary alloys are effective catalysts for the electrochemical oxygen evolution reaction (OER) in acidic solutions. Nevertheless, decreasing the Ir content to less than 50 at% ...while maintaining or even enhancing the overall electrocatalytic activity and durability remains a grand challenge. Herein, by dealloying predesigned Al‐based precursor alloys, it is possible to controllably incorporate Ir with another four metal elements into one single nanostructured phase with merely ≈20 at% Ir. The obtained nanoporous quinary alloys, i.e., nanoporous high‐entropy alloys (np‐HEAs) provide infinite possibilities for tuning alloy's electronic properties and maximizing catalytic activities owing to the endless element combinations. Particularly, a record‐high OER activity is found for a quinary AlNiCoIrMo np‐HEA. Forming HEAs also greatly enhances the structural and catalytic durability regardless of the alloy compositions. With the advantages of low Ir loading and high activity, these np‐HEA catalysts are very promising and suitable for activity tailoring/maximization.
To lower the Ir content and enhance the oxygen evolution reaction (OER) performance, a series of nanoporous high‐entropy alloys with ≈20 at% Ir are prepared by a dealloying method. Due to the multiprinciple element property and endless possibilities for electronic structure adjustment, a highly active AlNiCoIrMo catalyst is found for both OER and hydrogen evolution reaction (HER) in acidic media.
Abstract
Developing highly active and durable electrocatalysts for acidic oxygen evolution reaction remains a great challenge due to the sluggish kinetics of the four-electron transfer reaction and ...severe catalyst dissolution. Here we report an electrochemical lithium intercalation method to improve both the activity and stability of RuO
2
for acidic oxygen evolution reaction. The lithium intercalates into the lattice interstices of RuO
2
, donates electrons and distorts the local structure. Therefore, the Ru valence state is lowered with formation of stable Li-O-Ru local structure, and the Ru–O covalency is weakened, which suppresses the dissolution of Ru, resulting in greatly enhanced durability. Meanwhile, the inherent lattice strain results in the surface structural distortion of Li
x
RuO
2
and activates the dangling O atom near the Ru active site as a proton acceptor, which stabilizes the OOH* and dramatically enhances the activity. This work provides an effective strategy to develop highly efficient catalyst towards water splitting.
Designing and fabricating bifunctional electrocatalysts for both the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is crucial to high-performance rechargeable metal–air ...batteries. Herein, we introduce a generic dealloying procedure to fabricate nanoporous spinel high-entropy oxides (HEO) (AlCoFeMoCr)3O4 as the OER catalysts, incorporated with highly dispersed Pt or PtPdCuAgAu clusters/nanoparticles of ∼1.5 nm in diameters as the ORR catalysts on the porous HEO. Our combined experimental results and first-principles density functional theory (DFT) calculations clearly indicate that the ORR activity of Pt clusters can be enhanced and stabilized through strong interactions with the HEO substrates, and at the same time, the presence of Pt can boost the OER performance of the HEO. In particular, the nanoporous AlCoFeMoCr/Pt composite exhibits a comparable OER activity as the best reported data, while its ORR activity exceeds the performance of commercial Pt/C in alkaline solutions. We expect such multicomponent HEO/metal composite systems would provide a new combinatorial materials design path to ensure multiple catalytic functionalities.
We investigate the predictive validity of teacher licensure tests using data from the Massachusetts Tests for Educator Licensure (MTEL). MTEL scores predict teachers’ in-service performance ratings ...and contributions to student test scores (i.e., value added). We then explore whether these relationships vary for teacher candidates of color. Although candidates of color have lower first-time pass rates and are less likely to retake licensure tests, we do not find consistent evidence that MTEL scores are less predictive of student achievement gains. Finally, we find that some evidence that MTEL scores are more predictive of teacher performance ratings for teachers of color than for White teachers.
Human mitochondrial pyruvate carriers (hMPCs), which are required for the uptake of pyruvate into mitochondria, are associated with several metabolic diseases, including type 2 diabetes and various ...cancers. Yeast MPC was recently demonstrated to form a functional unit of heterodimers. However, human MPC-1 (hMPC-1) and MPC-2 (hMPC-2) have not yet been individually isolated for their detailed characterization, in particular in terms of their structural and functional properties, namely, whether they exist as homo- or heterodimers. In this study, hMPC-1 and hMPC-2 were successfully isolated in micelles and they formed stable homodimers. However, the heterodimer state was found to be dominant when both hMPC-1 and hMPC-2 were present. In addition, as heterodimers, the molecules exhibited a higher binding capacity to both substrates and inhibitors, together with a larger structural stability than when they existed as homodimers. Taken together, our results demonstrated that the hetero-dimerization of hMPCs is the main functional unit of the pyruvate metabolism, providing a structural insight into the transport mechanisms of hMPCs.
Chloride ion-pumping rhodopsin (ClR) in some marine bacteria utilizes light energy to actively transport Cl
into cells. How the ClR initiates the transport is elusive. Here, we show the dynamics of ...ion transport observed with time-resolved serial femtosecond (fs) crystallography using the Linac Coherent Light Source. X-ray pulses captured structural changes in ClR upon flash illumination with a 550 nm fs-pumping laser. High-resolution structures for five time points (dark to 100 ps after flashing) reveal complex and coordinated dynamics comprising retinal isomerization, water molecule rearrangement, and conformational changes of various residues. Combining data from time-resolved spectroscopy experiments and molecular dynamics simulations, this study reveals that the chloride ion close to the Schiff base undergoes a dissociation-diffusion process upon light-triggered retinal isomerization.
The traditional aircraft controller design is usually based on the off-line aerodynamic model. Due to the deviation of the off-line aerodynamic model, the flight quality is difficult to meet the ...requirements when the aircraft is flying in the real atmosphere. To solve this problem, this paper proposes a frequency domain identification-based improved adaptive nonlinear dynamic inversion (NDI) control method (FDI-ANDI). In this paper, an online recursive aerodynamic parameter identification method in the frequency domain is first designed, and then an adaptive dynamic inversion control method based on the online aerodynamic parameter identification results is established. Finally, aiming at the problem of the slow response speed of the NDI controller, an improved adaptive dynamic inversion control law is designed by using the method of series lead correction. Compared with the traditional control method, the adaptive dynamic inversion method based on online aerodynamic identification has stronger robustness and a faster response speed in the face of model uncertainty. The final simulation analysis shows that the method has a better control effect than the traditional control method.
Understanding the structure and functional mechanisms of cyanobacterial halorhodopsin has become increasingly important, given the report that Synechocystis halorhodopsin (SyHR), a homolog of the ...cyanobacterial halorhodopsin from Mastigocladopsis repens (MrHR), can take up divalent ions, such as SO42−, as well as chloride ions. Here, the crystal structure of MrHR, containing a unique “TSD” chloride ion conduction motif, was determined as a homotrimer at a resolution of 1.9 Å. The detailed structure of MrHR revealed a unique trimeric topology of the light-driven chloride pump, with peculiar coordination of two water molecules and hydrogen-mediated bonds near the TSD motif, as well as a short B–C loop. Structural and functional analyses of MrHR revealed key residues responsible for the anion selectivity of cyanobacterial halorhodopsin and the involvement of two chloride ion-binding sites in the ion conduction pathway. Alanine mutant of Asn63, Pro118, and Glu182 locating in the anion inlet induce multifunctional uptake of chloride, nitrate, and sulfate ions. Moreover, the structure of N63A/P118A provides information on how SyHR promotes divalent ion transport. Our findings significantly advance the structural understanding of microbial rhodopsins with different motifs. They also provide insight into the general structural framework underlying the molecular mechanisms of the cyanobacterial chloride pump containing SyHR, the only molecule known to transport both sulfate and chloride ions.
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•The structure of the cyanobacterial chloride pump containing a unique “TSD” motif was solved at 1.9 Å resolution.•The homotrimeric topology and key ion-conducting residues of MrHR differ with general halorhodopsins.•Mutations in the chloride inlet induce multifunctional uptake of Cl−, NO3−, SO42− ions.•The mutant structure of chloride inlet provides structural evidence on different anion accessibilities.
Irisin, a recently identified hormone secreted by skeletal muscle in response to exercise, exhibits anabolic effects on the skeleton primarily through the stimulation of bone formation. However, the ...mechanism underlying the irisin-stimulated anabolic response remains largely unknown. To uncover the underlying mechanism, we biosynthesized recombinant irisin (r-irisin) using an Escherichia coli expression system and used it to treat several osteoblast cell types. Our synthesized r-irisin could promote proliferation and differentiation of osteoblasts as evidenced by enhanced expression of osteoblast-specific transcriptional factors, including Runt-related transcription factor-2 (Runx2), Oster (Osx), as well as early osteoblastic differentiation markers such as alkaline phosphatase (Alp) and collagen type I alpha 1 (Col1a1). Furthermore, we showed that the promotion of r-irisin on the proliferation and differentiation of osteoblast lineage cells are preferentially through aerobic glycolysis, as indicated by the enhanced abundance of representative enzymes such as lactate dehydrogenase A (LDHA) and pyruvate dehydrogenase kinase 1 (PDK1), together with increased lactate levels. Suppression of r-irisin-mediated aerobic glycolysis with Dichloroacetate blunted its anabolic effects. The favorite of the aerobic glycolysis after r-irisin treatment was then confirmed in primary calvarial cells by metabolic analysis using gas chromatography–mass spectrometry. Thus, our results suggest that the anabolic actions of r-irisin on the regulation of osteoblast lineage cells are preferentially through aerobic glycolysis, which may help to develop new irisin-based bone anabolic agents.
•Our produced r-irisin promoted proliferation and early differentiation of osteoblasts.•The r-irisin preferentially stimulated aerobic glycolysis.•Activation of aerobic glycolysis may be a common feature of bone anabolism.
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