East Asian summer monsoon precipitation (EASMP) features complicated interdecadal variability with multiple time periods and spatial patterns. Using century-long datasets of HadISST, CRU ...precipitation, and the ECMWF twentieth-century reanalysis (ERA-20C), this study examines the joint influence of three oceanic interdecadal signals i.e., Pacific decadal oscillation (PDO), Atlantic multidecadal oscillation (AMO), and Indian Ocean Basin mode (IOBM) on the EASMP, which, however, is found not to be simply a linear combination of their individual effects. When PDO and AMO are out of phase, the same-sign SST anomalies occur in the North Pacific and North Atlantic, and a zonally orientated teleconnection wave train appears across the Eurasian mid-to-high latitudes, propagating from the North Atlantic to northern East Asia along the Asian westerly jet waveguide. Correspondingly, the interdecadal precipitation anomalies are characterized by a meridional tripole mode over eastern China. When PDO and AMO are in phase, with opposite sign SST anomalies in the North Pacific and North Atlantic, the sandwich pattern of anomalous stationary Rossby wavenumber tends to reduce the effect of the waveguide in the eastern Mediterranean region, and the teleconnection wave train from the North Atlantic travels only to western central Asia along a great circle route, causing Indian summer monsoon precipitation (ISMP) anomalies. The ISMP anomalies, in turn, interact with the teleconnection wave train induced by the PDO and AMO, leading to a meridional dipole mode of interdecadal precipitation anomalies over eastern China. Through the impact on the ISMP, the IOBM exerts significantly linear modulation on the combined impacts of PDO and AMO, especially over northern East Asia.
•EMD simulations are carried out to calculate the thermal conductivities and fractal dimensions.•The thermal conductivity increases linearly with decrease of fractal dimension of aggregations.•The ...liquid atoms in nanolayer are “dynamically balanced”.•The explanation based on Kapitza resistance for heat transfer enhancement by nanolayer is queried.
Nanofluid can enhance heat transfer due to the suspending nanoparticles. The mechanism of heat transportation by nanoparticles remains unclear so far. Aggregation of nanoparticles, one of the important mechanisms to elevate the thermal conductivity of nanofluid, was proved by not a few researches. However, the aggregation morphology of nanoparticles evaluated by fractal dimension will greatly influence the thermal conductivity of nanofluid. In this paper, equilibrium molecular dynamics simulations were carried out to calculate the thermal conductivity via Green-Kubo formula. In contemporary, fractal dimensions of the aggregations with various morphologies were obtained by Schmidt-Ott equation. Comparisons of the fractal dimension and thermal conductivity of the nanofluid with same volume fraction show us that, lower fractal dimension can deduce greater thermal conductivity. In addition, the difference of loose and compact aggregation can be read out of the pair correlation function near nanoparticles. And the solvent atoms in nanolayer are mobilized and dynamically balanced. This is helpful for us to understand the influence of aggregation morphology of nanoparticles on the thermal conductivity of nanofluid.
Single-site catalysts feature high catalytic activity but their facile construction and durable utilization are highly challenging. Herein, we report a simple impregnation-adsorption method to ...construct platinum single-site catalysts by synergic micropore trapping and nitrogen anchoring on hierarchical nitrogen-doped carbon nanocages. The optimal catalyst exhibits a record-high electrocatalytic hydrogen evolution performance with low overpotential, high mass activity and long stability, much superior to the platinum-based catalysts to date. Theoretical simulations and experiments reveal that the micropores with edge-nitrogen-dopants favor the formation of isolated platinum atoms by the micropore trapping and nitrogen anchoring of PtCl
, followed by the spontaneous dechlorination. The platinum-nitrogen bonds are more stable than the platinum-carbon ones in the presence of adsorbed hydrogen atoms, leading to the superior hydrogen evolution stability of platinum single-atoms on nitrogen-doped carbon. This method has been successfully applied to construct the single-site catalysts of other precious metals such as palladium, gold and iridium.
The aim of the current study was to compare the expression of microRNAs (miRNAs) in exosomes derived from human bone mesenchymal stem cells (hBMSCs) with and without chondrogenic induction. Exosomes ...derived from hBMSCs were isolated and identified. Microarray analysis was performed to compare miRNA expression between exosomes derived from hBMSCs with and without chondrogenic induction, and quantitative real‐time polymerase chain reaction (qRT‐PCR) was used to verify the differentially expressed miRNAs. hBMSCs were transfected with miRNA mimic to extract miRNA‐overexpressed exosomes. The results showed that most exosomes exhibited a cup‐shaped or round‐shaped morphology with a diameter of approximately 50‐200 nm and expressed CD9 and CD63. We detected 141 miRNAs that were differentially expressed with and without chondrogenic induction by over a twofold change, including 35 upregulated miRNAs, such as miR‐1246, miR‐1290, miR‐193a‐5p, miR‐320c, and miR‐92a, and 106 downregulated miRNAs, such as miR‐377‐3p and miR‐6891‐5p. qRT‐PCR analysis validated these results. Exosomes derived from hBMSCs overexpressing miR‐320c were more efficient than normal exosomes derived from control hBMSCs at promoting osteoarthritis chondrocyte proliferation, down‐regulated matrix metallopeptidase 13 and up‐regulated (sex determining region Y)‐box 9 expression during hBMSC chondrogenic differentiation. In conclusion, we identified a group of upregulated miRNAs in exosomes derived from hBMSCs with chondrogenic induction that may play an important role in mesenchymal stem cell‐derived exosomes in cartilage regeneration and, ultimately, the treatment of arthritis. We demonstrated the potential of these modified exosomes in the development of novel therapeutic strategies.
We performed microarray analysis compare miRNA expression between exosomes derived from hBMSCs with and without chondrogenic induction. We identified a group of upregulated miRNAs in exosomes derived from hBMSCs with chondrogenic induction that may play an important role in mesenchymal stem cell‐derived exosomes in cartilage regeneration and, ultimately, the treatment of arthritis.
WNT5A is known to be involved in the pathogenesis of osteoarthritis. This study investigated the molecular mechanism of exosomal miR-92a-3p and WNT5A in chondrogenesis and cartilage degeneration.
...Exosomal miR-92a-3p expression was assessed in vitro in a human mesenchymal stem cell (MSC) model of chondrogenesis and in normal and OA primary human chondrocytes (PHCs). MSCs and PHCs were treated with exosomes derived from MSC-miR-92a-3p (MSC-miR-92a-3p-Exos) or its antisense inhibitor (MSC-anti-miR-92a-3p-Exos), respectively. Small interfering RNAs (siRNAs) and luciferase reporter assay were used to reveal the molecular role of exosomal miR-92a-3p and WNT5A in chondrogenesis. The protective effect of exosomes in vivo was measured using Safranin-O and Fast Green staining and immunohistochemical staining.
Exosomal miR-92a-3p expression was elevated in the MSC chondrogenic exosome, while it was significantly reduced in the OA chondrocyte-secreted exosome compared with normal cartilage. Treatment with MSC-miR-92a-3p-Exos promoted cartilage proliferation and matrix genes expression in MSCs and PHCs, respectively. In contrast, treatment with MSC-anti-miR-92a-3p-Exos repressed chondrogenic differentiation and reduced cartilage matrix synthesis by enhancing the expression of WNT5A. Luciferase reporter assay demonstrated that miR-92a-3p suppressed the activity of a reporter construct containing the 3'-UTR and inhibited WNT5A expression in both MSCs and PHCs. MSC-miR-92a-3p-Exos inhibit cartilage degradation in the OA mice model.
Our results suggest that exosomal miR-92a-3p regulates cartilage development and homeostasis by directly targeting WNT5A. This indicates that exosomal miR-92a-3p may act as a Wnt inhibitor and exhibits potential as a disease-modifying osteoarthritis drug.
•Isotropic and azimuthally anisotropic Vs models are established for the central-southern Tanlu fault in eastern China.•The new Vs models suggest a southern termination of the Tanlu fault and relics ...of delaminated lithosphere.•A four-stage tectonic model is proposed for the initiation and tectonic evolution of the Tanlu fault.
The Tanlu fault is a well-known lithosphere-cutting, strike-slip fault in eastern China and it has played an important role in regional plate tectonics since the middle Mesozoic. However, the initiation mechanisms and tectonic evolution of the Tanlu fault remain controversial, in part due to the absence of constraints from deep structures. In this study, we inverted 5–150 s surface-wave dispersion data collected from 253 permanent stations and 111 temporary stations in the vicinity of the central-southern Tanlu fault and obtained both isotropic and azimuthally anisotropic shear-wave velocity (Vs) models in the crust and upper mantle simultaneously. The new Vs models reveal unprecedented multiple patterns of anomalies. There is, for example, an arc-shaped pattern of fast directions found in the South China plate (SCP), providing direct evidence of the sudden termination of the Tanlu fault at its southern end; orogen-parallel fast directions and high-velocity anomalies were detected beneath the Dabie and Sulu orogens, which are believed to be the residue of the delaminated lithosphere. Based on the evidence collected, we propose a four-stage tectonic model for the Tanlu fault. The tectonic model suggests that the area has been subjected to multiple geologic processes since the Early Mesozoic, including oceanic-continental collision, continental-continental collision, break-off of oceanic slabs, lithospheric delamination, and convective erosion resulting from corner flow. As such, the proposed tectonic model reconciles the newly discovered Vs anomalies as well as various previous findings, providing profound insight into regional deformations and the evolution of the Tanlu fault and its adjacent areas.
Abstract
Single-atom catalysts have been widely investigated for several electrocatalytic reactions except electrochemical alcohol oxidation. Herein, we synthesize atomically dispersed platinum on ...ruthenium oxide (Pt
1
/RuO
2
) using a simple impregnation-adsorption method. We find that Pt
1
/RuO
2
has good electrocatalytic activity towards methanol oxidation in an alkaline media with a mass activity that is 15.3-times higher than that of commercial Pt/C (6766 vs. 441 mA mg
‒1
Pt
). In contrast, single atom Pt on carbon black is inert. Further, the mass activity of Pt
1
/RuO
2
is superior to that of most Pt-based catalysts previously developed. Moreover, Pt
1
/RuO
2
has a high tolerance towards CO poisoning, resulting in excellent catalytic stability. Ab initio simulations and experiments reveal that the presence of Pt‒O
3f
(3-fold coordinatively bonded O)‒Ru
cus
(coordinatively unsaturated Ru) bonds with the undercoordinated bridging O in Pt
1
/RuO
2
favors the electrochemical dehydrogenation of methanol with lower energy barriers and onset potential than those encountered for Pt‒C and Pt‒Ru.
The narrow field of view (FOV) has always been one of the most with limitations that drag the development of holographic three-dimensional (3D) near-eye display (NED). The complex amplitude ...modulation (CAM) technique is one way to realize holographic 3D display in real time with the advantage of high image quality. Previously, we applied the CAM technique on the design and integration of a compact colorful 3D-NED system. In this paper, a viewing angle enlarged CAM based 3D-NED system using a Abbe-Porter scheme and curved reflective structure is proposed. The viewing angle is increased in two steps. An Abbe-Porter filter system, composed of a lens and a grating, is used to enlarge the FOV for the first step and, meanwhile, realize complex amplitude modulation. A curved reflective structure is used to realize the FOV enlargement for the second step. Besides, the system retains the ability of colorful 3D display with high image quality. Optical experiments are performed, and the results show the system could present a 45.2° diagonal viewing angle. The system is able to present dynamic display as well. A compact prototype is fabricated and integrated for wearable and lightweight design.
An innovative approach based on a surface functional monomer-directing strategy for the construction of a sensitive and selective molecularly imprinted electrochemical sensor for patulin recognition ...is described. A patulin imprinted platinum nanoparticle (PtNP)-coated poly(thionine) film was grown on a preformed thionine tailed surface of PtNP-nitrogen-doped graphene (NGE) by electropolymerization, which provided high capacity and fast kinetics to uptake patulin molecules. Thionine acted not only as a functional monomer for molecularly imprinted polymer (MIP), but also as a signal indicator. Enhanced sensitivity was obtained by combining the excellent electric conductivity of PtNPs, NGE, and thionine with multisignal amplification. The designed sensor displayed excellent performance for patulin detection over the range of 0.002–2 ng mL–1 (R2 = 0.995) with a detection limit of 0.001 ng mL–1 for patulin. In addition, the resulting sensor showed good stability and high repeatability and selectivity. Furthermore, the feasibility of its applications has also been demonstrated in the analysis of real samples, providing novel tactics for the rational design of MIP-based electrochemical sensors to detect a growing number of deleterious substances.
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•Microplastics reduce the efficiency of wastewater treatment processes.•Microplastics affect the effluent quality of wastewater treatment plants.•Microplastics inhibit sludge ...hydrolysis, acidification, and methanogenesis.•Negative impacts of microplastics come from the leaching of toxic additives and ROS production.
Microplastics are widely used and inevitably released into the environment, which can be easily enriched in wastewater treatment plants. This review assesses their potential effects on wastewater and sludge treatment and the methods for removing microplastics from wastewater and sludge. Firstly, recent advances of the methods for purification and detection of microplastics in wastewater and sewage sludge environment were reviewed. Then, the effects of microplastics on wastewater and sludge treatment and the mechanisms were discussed. It can be seen that when the size of microplastics reached the nanometer level, they infiltrated into the biofilm and produce ROS, which showed acute inhibitory effect on microbial community, key enzymes, metabolic intermediates and final products. Due to their large specific surface area and hydrophobic surface, persistent organic pollutants, metals and pathogens could be easily adsorbed on the surface of microplastics. As various additives were added in the production of plastics, the adsorption of environmental micropollutants and the exudation of additives made the mechanism of microplastics affecting sewage and sludge treatment more complicated. Also, the methods for removing microplastics from wastewater and sludge were reviewed and their removal efficiencies were compared. Finally, the problems that need to be addressed in the future were pointed out, and the key points for future investigation were proposed.
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