We investigate constraints on some key cosmological parameters by confronting metastable dark energy (DE) models with different combinations of the most recent cosmological observations. Along with ...the standard ΛCDM model, two phenomenological metastable DE models are considered: (i) DE decays exponentially, (ii) DE decays into dark matter. We find that: (1) when considering the most recent supernovae and BAO data, and assuming a fiducial ΛCDM model, the inconsistency in the estimated value of the parameter obtained by either including or excluding Planck cosmic microwave background (CMB) data becomes very much substantial and points to a clear tension; (2) although the two metastable DE models that we study provide greater flexibility in fitting the data, and they indeed fit the supernovae (SNe) Ia+BAO data substantially better than ΛCDM, they are not able to alleviate this tension significantly when CMB data are included; (3) while local measurements of the Hubble constant are significantly higher relative to the estimated value of H0 in our models (obtained by fitting to SNe Ia and BAO data), the situation seems to be rather complicated with hints of inconsistency among different observational data sets (CMB, SNe Ia+BAO, and local H0 measurements). Our results indicate that we might not be able to remove the current tensions among different cosmological observations by considering simple modifications of the standard model or by introducing minimal DE models. A complicated form of expansion history, different systematics in different data and/or a nonconventional model of the early universe might be responsible for these tensions.
Abstract Based on the Heliospheric Imager-1 images of the STEREO twin spacecraft, we established the CORrelation-Aided Reconstruction (CORAR) technique to locate and reconstruct the 3D structures of ...solar wind transients in interplanetary space. Here, we extend the CORAR method to images of COR2 on board STEREO to study the evolution of small-scale transients in the outer corona from 2010 January to May. We confirm that the transients can be located and reconstructed well by comparing the results with those of a self-similar expanding model. The speed distribution of the reconstructed transients generally shows the typical characteristics of the slow solar wind. We further study the sources of the transients on the Sun, and find that most reconstructed transients are located near the top of streamer belts or the heliospheric current sheet and can be tracked back to the boundaries of the closed-field and open-field regions along the field lines extrapolated by corona models. The formation mechanisms of these transients in the slow solar wind are also discussed.
Android, the most popular mobile OS, has around 78% of the mobile market share. Due to its popularity, it attracts many malware attacks. In fact, people have discovered around 1 million new malware ...samples per quarter, and it was reported that over 98% of these new malware samples are in fact "derivatives" (or variants) from existing malware families. In this paper, we first show that runtime behaviors of malware's core functionalities are in fact similar within a malware family. Hence, we propose a framework to combine "runtime behavior" with "static structures" to detect malware variants. We present the design and implementation of Monet, which has a client and a backend server module. The client module is a lightweight, in-device app for behavior monitoring and signature generation, and we realize this using two novel interception techniques. The backend server is responsible for large scale malware detection. We collect 3723 malware samples and top 500 benign apps to carry out extensive experiments of detecting malware variants and defending against malware transformation. Our experiments show that Monet can achieve around 99% accuracy in detecting malware variants. Furthermore, it can defend against ten different obfuscation and transformation techniques, while only incurs around 7% performance overhead and about 3% battery overhead. More importantly, Monet will automatically alert users with intrusion details so to prevent further malicious behaviors.
Lead halide perovskite solar cells have recently emerged as a very promising photovoltaic technology due to their excellent power conversion efficiencies; however, the toxicity of lead and the poor ...stability of perovskite materials remain two main challenges that need to be addressed. Here, for the first time, we report a lead-free, highly stable C6H4NH2CuBr2I compound. The C6H4NH2CuBr2I films exhibit extraordinary hydrophobic behavior with a contact angle of ∼90°, and their X-ray diffraction patterns remain unchanged even after 4 h of water immersion. UV/vis absorption spectrum shows that C6H4NH2CuBr2I compound has an excellent optical absorption over the entire visible spectrum. We applied this copper-based light absorber in printable mesoscopic solar cell for the initial trial and achieved a power conversion efficiency of ∼0.5%. Our study represents an alternative pathway to develop low-toxic and highly stable organic–inorganic hybrid materials for photovoltaic application.
This study investigates the impact of digital media on promoting high-quality skills by assessing its impact on collaborative education and technological skills within Chinese higher education. A ...survey-based strategy was adopted and three explanatory variables were incorporated, namely students’ learning using social media, students’ experience of using social media in teaching and social media usage frequency. The learner’s motivation was also included as a mediator. The study collected data from university students across mainland China, focusing on those engaged in learning using social media platforms. Structural Equation Modelling (SEM) was employed to analyze the data. The findings showed that usage of social media for learning positively impacts collaborative education, indicating students’ preference for interactive projects and online lectures on social media. Regarding the impact on technological skills, the findings showed that social media usage frequency positively influencedtechnological skills among students in Chinese universities. Additionally, it was found that learner’s motivation significantly mediated the association of social media usage frequency with collaborative education and technological skills. Learner’s motivation played a significant mediating role in the relationship between students’ experience of social media learning and collaborative education. The findings hold implications for educators, institutions, and policymakers striving to leverage digital media to advance high-quality skills in educational settings.
Targeted protein degradation (TPD) technology has drawn significant attention from researchers in both academia and industry. It is rapidly evolved as a new therapeutic modality and also a useful ...chemical tool in selectively depleting various protein targets. As most efforts focus on cytosolic proteins using PROteolysis TArgeting Chimera (PROTAC), LYsosome TArgeting Chimera (LYTAC) recently emerged as a promising technology to deliver extracellular protein targets to lysosome for degradation through the cation-independent mannose-6-phosphate receptor (CI-M6PR). In this study, we exploited the potential of the asialoglycoprotein receptor (ASGPR), a lysosomal targeting receptor specifically expressed on liver cells, for the degradation of extracellular proteins including membrane proteins. The ligand of ASGPR, triantennary N-acetylgalactosamine (tri-GalNAc), was conjugated to biotin, antibodies, or fragments of antibodies to generate a new class of degraders. We demonstrated that the extracellular protein targets could be successfully internalized and delivered into lysosome for degradation in liver cell lines specifically by these degraders. This work will add a new dimension to TPD with cell type specificity.
Fibroblasts excessive proliferation was considered as a decisive reason for epidural fibrosis, which was known as a serious complication of lumbar laminectomy. As a traditional Chinese medicine, ...triptolide (TP) was used to be proved effective in preventing several fibrosis scar formation diseases. However, little is known about the effect of TP on preventing epidural fibrosis and its possible mechanism. Here, we performed in vitro and in vivo experiments to detect the possible mechanism of TP in preventing epidural fibrosis. In vitro, the effect of TP on impacting fibroblasts proliferation activities was detected by CCK-8, cell cycle assay and EdU incorporation assay. Also, the expressions of cell proliferation protein markers and the expressions of p-PI3K, p-AKT, p-mTOR were detect by Western blot. Besides, the effect of TP on inducing fibroblast apoptosis and autophagy was tested by Western blots, flow cytometry, TUNEL staining, Transmission electron microscope (TEM) analysis and LC3 immunofluorescent staining. The results suggested that TP could suppress the activation of PI3K/AKT/mTOR signaling pathway. Meanwhile, TP could inhibit fibroblast proliferation and induce fibroblast apoptosis as well as autophagy, which was known as two cellular self-destructions. Furthermore, we speculated the possible molecular pathway, through which that TP could inhibit fibroblast proliferation, induce fibroblast apoptosis and autophagy. We used PI3-kinase activator (740Y-P) to activate the PI3K/AKT/mTOR signaling. Activation of PI3K/AKT/mTOR signaling pathway increase the proliferation of fibroblasts and suppressed the autophagy and apoptosis induced by TP. In vivo, we built epidural fibrosis models in rats and locally applied TP of various concentrations. Hematoxylin–eosin (HE) and Masson's trichrome were used to detect the effect of TP on reducing epidural fibrosis. And the results showed that TP could significantly reduce the surgery-induced epidural fibrosis. In conclusion, the results above shown that TP could reduce epidural fibrosis formation, and the potential mechanism might through inhibiting fibroblast proliferation and stimulating apoptosis and autophagy via suppressing PI3K/AKT/mTOR signaling pathway. It might provide a novel thought for reducing surgery-induced epidural fibrosis.
The effects of polyethylene oxide (PEO) homopolymer on the gelation behavior of a PEO
100
-PPO
65
-PEO
100
triblock copolymer (Pluronic F127) were explored in aqueous solution under non-isothermal ...and isothermal conditions. Under non-isothermal conditions (temperature sweep test), two transition points were observed on increasing temperature, that is, at lower and upper gelation temperatures (LT
gel
and UT
gel
, respectively). Between LT
gel
and UT
gel
, F127 aqueous solutions maintained a hard gel state. Both molecular weight (MW) and PEO concentration affected these two gelation temperatures. In particular, relative molecular weight (MW
rel
≡ molecular weight of PEO homopolymer/PEO segment of F127) affected LT
gel
. LT
gel
decreased on increasing PEO concentration at MW
rel
values of <1, but increased on increasing PEO concentration at MW
rel
values of >1. On the other hand, UT
gel
decreased with increasing PEO concentration regardless of MW
rel
. Under isothermal conditions (fixed temperature between LT
gel
and UT
gel
), the effects of PEO homopolymer on the mechanical properties of F127 hard gel were systemically investigated using small and large amplitude oscillatory shear tests. In the linear viscoelastic regime, total intra-cycle stress and elastic intra-cycle stress were similar, and viscous response increased on increasing PEO concentration. However, at large strain amplitudes, hard gels showed intra-cycle stiffening but inter-cycle softening behavior. In addition, on increasing PEO concentrations, viscous nonlinearities underwent strain-rate thickening followed by strain-rate thinning.
The sensing behaviors of monolayer antimonide phosphorus (SbP) for hydrogen sulfide (H2S) are investigated by means of the density functional theory. In this paper, we calculated the best adsorption ...configuration, charge transfer, adsorption distance, band gap, electronic structure and recovery time of H2S on the SbP monolayer and mental-doped SbP (X-SbP). The calculated results indicate that Al atom replaces Sb atom of SbP (Al-Sb-SbP), adsorption capacity was greatly increased, but the covalent bond formed between the gas molecules and the substrate was not suitable for sensing materials. And though Co or Ni atom could improve the interactions between H2S gas and SbP sheets, the recovery time was too long. It was also not suitable for the sensor material of H2S gas. However, for Pd doped SbP, Pd-Sb and Pd-P doping all exhibit excellent gas sensing performance for H2S gas with the adsorption energy of -0.677eV and -0.520eV, the charge transfer 0.1113e and 0.0930e, the recovery time 0.19s and 5.30and#215;10-4 s, respectively. These characters made Pd-SbP suitable for H2S gas sensing material. Which further analysis we knew that these changes were mainly due to the orbital hybridization between the s, p orbitals of Pd atom and the p orbitals of S atom. Theoretical studies show that Pd-doped SbP is a promising H2S gas sensing material
The deterioration of concrete materials in the sewage environment is prominent, significantly shortening the structure's service life. Based on the composite modification method, modified basalt ...fiber high-durability concrete is proposed to solve the problem of insufficient material durability in the sewage environment. The acid environment erosion test was carried out for the modified concrete materials. The macroscopic performance indexes were obtained, such as apparent corrosion characteristics, water absorption rate and compressive strength. The corrosion mechanism and deterioration law of concrete materials under an acid environment were revealed by combining the analysis of the fine structure and corrosion product composition. The results show that the hydration reaction of the modified concrete was adequate. The generation of C–S–H gel and Ca(OH)2 increased significantly. The porosity was reduced by 40%, and the initial strength was increased by 12%. After 240d corrosion, the strength of ordinary concrete was degraded by 41%. The degradation rate of modified concrete was 26%, its residual strength was 1.4 times that of ordinary concrete, and its corrosion-resistant ability was greatly improved. Based on the experiment, the corrosion resistance mechanism analysis was carried out, and it was found that the inorganic aluminium salt compound salt crystal expansion modification effect is better than the sodium methyl silicate reticulated resin film modification. However, after double doping, the corrosion resistance is reduced instead, and it is recommended that inorganic aluminium salts be preferred as anti-corrosion and anti-seepage adding materials. The research results of this paper can better enhance the acid environment erosion resistance of concrete, engineering application prospect is good.
•Put forward the concept of composite modified anti-corrosion.•The mechanism of new concrete protection under an acidic environment was revealed.•New technology for corrosion protection of sewage environmental engineering.
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