2D metal chalcogenide materials have received enormous attention due to their extraordinary bio-chemical, electronic, magnetic, thermal and optical properties. Compared with the typical ...two-dimensional transition metal dichalcogenides (TMDs) and topological insulators, cuprous sulfide (Cu
2
S) has very different two-dimensional lattice structures, along with excellent electro-catalysis and high conductivity. However, the nonlinear optical properties of Cu
2
S have never been studied until now. Here, the nonlinear photonics characteristics of Cu
2
S and its application in ultrafast lasers have been systematically studied for the first time. Through optical deposition of Cu
2
S nanosheets on a tapered fiber, the nonlinear optical properties of Cu
2
S nanosheets are measured through the interaction with the evanescent field. The results indicate that superior nonlinear saturable absorption properties with a modulation depth of 0.51% are achieved. An erbium-doped fiber (EDF) laser is constructed to verify the performance of the Cu
2
S saturable absorber (SA). The results show that an output pulse with 8.06 MHz repetition rate, 1.04 ps pulse duration, 1530.4 nm central wavelength and 3.1 nm spectral width without an obvious Kelly sideband is obtained. Considering the diversity of the metal chalcogenide family, various engineering applications may be developed from the nonlinear saturable absorption characteristics of Cu
2
S, including optical fiber communication/sensing, precision optical metrology, material processing and nonlinear optics.
The nonlinear optical properties of cuprous sulfide have been studied. The successful application in Er-doped fiber laser has proved cuprous sulfide as a novel, promising materials in the field of ultra-fast photonics.
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Highly sensitive and selective NO2 sensor for ppb-level detection at room temperature was constructed using MOF-derived Cu2O–CuO octahedrons as sensing material.
•Cu2O–CuO octahedrons ...were fabricated by the thermal decomposition of Cu-based MOFs.•Cu2O–CuO p–p heterojunctions were formed in the octahedrons.•Cu2O–CuO octahedrons showed an increased surface O2- species absorbing capability.•Cu2O–CuO exhibited sensitive and selective detection of ppb-level NO2 at 25 °C.•The gas-sensing enhancement mechanism of Cu2O–CuO octahedrons was proposed.
Cu2O–CuO heterojunction octahedrons were fabricated by the thermal decomposition of Cu-based metal–organic framework (MOF) precursors. The adsorbed oxygen species (O2-) content was visibly increased by constructing such kind of p–p heterojunctions. Compared with commercial CuO powder, this kind of Cu2O–CuO octahedrons exhibited much better sensing properties to NO2. At room temperature (RT, 25 °C), the Cu2O–CuO octahedrons showed a higher response, reaching 8.25–500 ppb NO2, which was 2.88 times higher than that of CuO powder. Besides good NO2 stability and selectivity, a low detection concentration down to 10 ppb was also revealed at RT for the Cu2O–CuO octahedrons. From our perspective, the enhanced NO2 sensing properties of the Cu2O–CuO octahedrons can be mainly attributed to the formation of Cu2O–CuO p–p heterojunctions, facilitating the adsorption of more O2- species to participate in the sensing reaction. The results here demonstrated that MOF-derived Cu2O–CuO octahedrons with a p–p heterojunction construction had a good potential for sensitive and selective detection of ppb-level NO2 at RT.
A recent study reported the cardioprotective effects mediated by cardiac fibroblasts (CFs) during acute phase of ischaemia-reperfusion injury (IRI). Little is known about whether ...exosomes/microvesicles mediate this beneficial effect and whether ischaemia post-conditioning (Postcon) can regulate this process. Here, we aimed to investigate the cardioprotective effect of CFs-exosomes/microvesicles and whether Postcon can regulate this effect.
By using transwells co-culture system, we found that hypoxia-reoxygenation (H/R) significantly increased the exosomes/microvesicles secretion of CFs and CFs protected H9C2 cells against H/R injury and Postcon could amplify these effects. Inhibition of CFs exosomes/microvesicles secretion led to a significant abrogation on the amplified protective effect of H/R-Postcon. We further demonstrated that Postcon enhanced the cardioprotective effect of CFs-exosomes/microvesicles both in vitro and in vivo. To detect the underlying mechanism, exosomes/microvesicles microRNAs were analysed by RNA sequencing and quantitative polymerase chain reaction, our results revealed that miR-423-3p expression was selectively enhanced by Postcon in CFs exosomes/microvesicles. By co-culture H9C2 cells with CFs-exosomes/microvesicles enriching with miR-423-3p, we demonstrated that H/R-Postcon exerted cardioprotective effects by upregulation of miR-423-3p in CFs-exosomes/microvesicles. RNA-fluorescence in situ hybridization and qPCR demonstrated that the decreasing of miR-423-3p is closely related to IRI, by inhibited miR-423-3p expression with its antagomir in vivo, we demonstrated that miR-423-3p plays an essential mediate role in I/R-Postcon-induced cardioprotection against I/R in vivo, Postcon may exert cardioprotective effect by upregulation of miR-423-3p in CFs exosomes/microvesicles. Gain- and loss-of-function approaches suggested that rescuing the down-regulated miR-423-3p might be a potential strategy to protect the cardiomyocytes against H/R. Using computational predictions tools and luciferase reporter assay, we demonstrated that miR-423-3p regulates the expression of Ras-related protein Rap-2c (RAP2C) in H9C2 cells, and knockdown of RAP2C by siRNA obviously increased cell viability and reduced apoptosis in H9C2 cells under H/R.
In conclusion, we demonstrated, for the first time, that CFs participate in cardioprotective effects via an exosomes/microvesicles pathway during the acute phase of IRI and Postcon can enhance this effect by upregulating the expression of CFs exosomes/microvesicles miR-423-3p, which targets the downstream effector RAP2C.
•Synthesis of γ-PGA-Fe3O4-GO-(o-MWCNTs) nanocomposite via a simple one-pot reaction.•γ-PGA-Fe3O4-GO-(o-MWCNTs) show obvious adsorption capacity for metal ions.•γ-PGA-Fe3O4-GO-(o-MWCNTs) can be ...separated more easily from solution systems.•Addition of o-MWCNTs solves the serious aggregation problem of GO.
A novel hybrid adsorbent, anionic polypeptide poly(γ-glutamic acid)—(γ-PGA) functionalized magnetic Fe3O4-GO-(o-MWCNTs) hybrid nanocomposite was successfully prepared via a simple one-pot reaction. The as-prepared γ-PGA-Fe3O4-GO-(o-MWCNTs) composites were characterized via SEM, TEM, FTIR, XRD, TGA, AFM, zeta potential analysis and magnetic properties analysis. The results indicate that the addition of o-MWCNTs solves the serious aggregation problem of GO and thus makes the GO exposed more grafted sites bonded to large amount of γ-PGA molecule chains. The prepared γ-PGA-Fe3O4-GO-(o-MWCNTs) composites not only have a higher specific surface area to offer abundant surface adsorption sites, but also can be separated more easily from solution systems. Furthermore, the adsorption tests of the γ-PGA-Fe3O4-GO-(o-MWCNTs) were analyzed in Cd(II), Cu(II) and Ni(II) solutions at various pH values, contact time, and initial concentrations of ions. This work indicates that the hybrid adsorbent can be the suitable absorbent materials for various types of heavy metal ions pollution removal and exhibit higher adsorbing capacities in the pH range of 2–10. Its maximum removal capacity calculated by Langmuir model under the optimal conditions toward Cd(II), Cu(II) and Ni(II) is 625.00, 574.71 and 384.62 mg/g, respectively. The adsorption process was well described by the pseudo-second-order kinetics model and the Langmuir isotherm model, respectively. The adsorption mechanism may involve characteristic coordination bonding and electrostatic attraction between γ-PGA-Fe3O4-GO-(o-MWCNTs) and metal ions. Additionally, anionic polypeptide γ-PGA-Fe3O4-GO-(o-MWCNTs) composite can be easily regenerated and recycled at least for three adsorption–desorption recycles. The unique characteristics render the composite highly promising as an advanced adsorbent material for the removal of heavy metal ions.
As a member of the 2D transition metal chalcogenides (TMCs), 2D Ag2S with large absorption coefficient, broadband optical response, extraordinary metal‐like ductility, high plastic deformation ...strain, unique layered structure, and very low solubility has offered a platform for achieving tremendous success in various fields. Great achievements have been made in exploring the linear optical, mechanical, and photoelectric properties of 2D Ag2S nanosheets. However, the nonlinear optical properties of 2D Ag2S nanosheets and their applications in ultrafast photonics have not been studied. The saturable absorption property of 2D Ag2S nanosheets is experimentally illustrated at the telecommunication band with a large optical modulation depth of 15.5% and a low saturable intensity of 250.4 MW cm−2. Moreover, the 229th harmonic soliton molecule with repetition rate of 1.1 GHz based on 2D Ag2S saturable absorber is realized at the telecommunication band for the first time to the authors' knowledge. Thankfully, 2D Ag2S nanosheets display excellent nonlinear optical properties suggesting that this may open a new door for advanced photonic devices based on 2D Ag2S nanosheets.
As a member of the 2D transition metal chalcogenides (TMCs), 2D Ag2S with large absorption coefficient, broadband optical response, and unique layered structure has offered a platform for achieving tremendous success in various fields. Herein, an Ag2S saturable absorber (SA) is incorporated into an Er‐doped fiber laser to achieve a 229th harmonic soliton molecule, corresponding to a repetition frequency of 1.1 GHz for the first time.
We introduce in this Letter an exact solvable BCS-Hubbard model in arbitrary dimensions. The model describes a p-wave BCS superconductor with equal spin pairing moving on a bipartite (cubic, square, ...etc.) lattice with on-site Hubbard interaction U. We show that the model becomes exactly solvable for arbitrary U when the BCS pairing amplitude Δ equals the hopping amplitude t. The nature of the solution is described in detail in this Letter. The construction of the exact solution is parallel to the exactly solvable Kitaev honeycomb model for S=1/2 quantum spins and can be viewed as a generalization of Kitaev's construction to S=1/2 interacting lattice fermions. The BCS-Hubbard model discussed in this Letter is just an example of a large class of exactly solvable lattice fermion models that can be constructed similarly.
The Zhangbaling–Guandian area is located in the eastern part of Anhui Province, China, and contains several small Au-Cu deposits and occurrences that highlight the prospectivity of this area for ...future mineral exploration. Recent research has determined that machine learning can identify potentially mineralization-related geochemical anomalies that represent targets for mineral exploration. However, the majority of this previous research has focused on identifying geochemical anomalies based on individual sample points but has not incorporated associated data such as the spatial characteristics of the shape, overlap, and zonation within multivariate geochemical anomalies and haloes. Here, we present a convolutional neural network algorithm based approach to identify areas prospective for Au exploration based on the multielement geochemical maps. This approach considers various spatial characteristics and employs a transfer learning method to reduce the influence of the limited number of known deposits and occurrences in this area, accelerating convergence rates and improving the accuracy of the model. The training results indicate that the accuracy of each training model is >99 and cross-entropy loss values are < 0.1. The results for the entirety of the study area indicate that about 88% of the known mineralization and mineralized occurrences are located in the prospective areas identified during this study. These results indicate that combining geochemical data with an approach employing convolutional neural network algorithms and transfer learning methods can effectively outline the Au mineralization prospectivity of relatively unexplored regions. This indicates that this type of approach could be a useful addition for future mineral exploration using geochemical data. In addition, the use of convolutional neural network approaches yields more accurate identification of geochemical anomalies and can include more geochemical variables, meaning that more geochemical data can be used in convolutional neural network-based approaches to target identification and mineral prospectivity modeling than is used in conventional geochemical anomaly identification.
•Geochemical anomalies relating to mineralization can be identified more accurately using a transfer learning method.•This approach allowed the identification of the morphological, overlapping and zoning characteristics of multivariable geochemical anomalies.•This research yielded several favorable areas for future Au-Cu exploration within the Zhangbaling–Guandian area.
In this paper, we propose a visual saliency detection algorithm from the perspective of reconstruction error. The image boundaries are first extracted via superpixels as likely cues for background ...templates, from which dense and sparse appearance models are constructed. First, we compute dense and sparse reconstruction errors on the background templates for each image region. Second, the reconstruction errors are propagated based on the contexts obtained from K-means clustering. Third, the pixel-level reconstruction error is computed by the integration of multi-scale reconstruction errors. Both the pixellevel dense and sparse reconstruction errors are then weighted by image compactness, which could more accurately detect saliency. In addition, we introduce a novel Bayesian integration method to combine saliency maps, which is applied to integrate the two saliency measures based on dense and sparse reconstruction errors. Experimental results show that the proposed algorithm performs favorably against 24 state-of-the-art methods in terms of precision, recall, and F-measure on three public standard salient object detection databases.
In recent years, numerous geodynamic studies have concentrated on serpentinites and the serpentinization processes that occur within subduction zones. However, as an important host phase for Mg, ...whether Mg isotopic fractionation occurs during peridotite serpentinization is still unclear. In our study, we conducted high-precision Mg isotope analyses on serpentinized peridotites and forearc serpentinites from the Mariana subduction zone. Except for one sample affected by strong late weathering with clay formation, which had an anomalously high δ26Mg value (0.01 ± 0.04‰), the moderately serpentinized peridotites (−0.24 ± 0.04‰, 2SD, n = 3) and deep (>40 mbsf) serpentinites (−0.24 ± 0.02‰, 2SD, n = 3) have Mg isotopic compositions consistent with mantle peridotites (−0.25 ± 0.04‰). Shallow serpentinites display slightly higher δ26Mg values (−0.19 ± 0.04‰, 2SD, n = 15) than mantle peridotites, and these values tend to increase toward the seafloor. These high δ26Mg values of forearc serpentinites cannot be attributed to serpentinizing fluid metasomatism and mantle wedge serpentinization processes, while post-serpentinization alteration involving brucite dissolution played a dominant role. Rayleigh fractionation simulations suggest that the heavy Mg isotopes are preferentially allocated to serpentinites during the post-serpentinization alteration process, where the calculated ∆26Mgbrucite-fluid varies from 0.1‰ to 0.8‰. This study deduces that the process of serpentinite dehydration in the subarc mantle cannot significantly change the Mg isotopic composition of arc lavas because serpentinite itself has a mantle-like Mg isotopic composition. Moreover, the fluids released by the brucite dissolution process have a low δ26Mg value, making an important contribution to the Mg budget of modern ocean seawater.
The rhizosphere microbiome facilitates a range of beneficial functions for its host plant. Thus, exploring the functionality of the rhizosphere microbiome and its underlying driving factors are ...fundamental for understanding how host plants benefit from their microbial symbionts. Herein, we utilized deep metagenomics sequencing to explore the rhizosphere microbiome in three rice (Oryza sativa L.) cultivars (hybrid rice and two japonica cultivars) that were planted in three spatially distant locations. Although rhizosphere prokaryotic communities were primarily affected by planting location, rice genotype signs were still detected. After the effect of planting location was ruled out, the top 24 genotype-discriminatory taxa were found to contribute 85.2% of the diagnostic accuracy for rice cultivars. The significant associations between the measured enzyme activities and the relative abundances of their coding genes validated that the recruitment of different rhizosphere microbes by hybrid rice and japonica cultivars further resulted in divergences in microbe-mediated functions. Compared with that in japonica, the rhizosphere in hybrid rice more efficiently mineralized N and P from organic matter, while mitigated N and K losses. The structural equation model depicted that the rice cultivars imposed direct (host-genotype-associated feature) and indirect (recruitment of specific rhizosphere microbiomes) effects on yield. Collectively, a conceptual model was constructed to infer the collective interplay among rice cultivars, rhizosphere microbiomes, and yield. Our findings provided novel insights into the molecular mechanism underlying the associations among rice cultivars, rhizosphere microbiomes, and yield.
•Rhizosphere microbiomes are primarily affected by geographic planting location, with detectable rice genotype signs.•Rice cultivar-discriminatory taxa contribute 85.2% of the diagnostic accuracy for cultivars.•Microbial enzyme activities are significantly associated with abundances of their coding genes.•Compared with japonica, Rhizosphere microbes in hybrid rice more efficiently mineralize N and P, while mitigate N and K losses than these in japonica.•Conceptual model infers the interplay between rice cultivar, rhizosphere microbiome and yield.
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