Sialon ceramics were prepared by the nitridation of Si, Al and Al
2
O
3
powders with the transition metals (Fe, Co, Ni) catalysts. The phase composition, microstructure and mechanical properties of ...specimens were studied. Compared with the catalyst-free specimen, the addition of Fe, Co and Ni greatly promoted the nitridation process of Sialon ceramics and improved the weight gain rate and mechanical properties of specimens. With the increased content of catalysts, the apparent porosity of the products decreased first and then increased, contrary to flexural strength and compressive strength. The specimen with 2.5 wt% Fe had the highest flexural strength 145.8 MPa, and it exhibited the highest compressive strength of 594.6 MPa when Co content was 2.5 wt%, whereas they were 71.9 and 78.7 MPa, respectively, when without catalyst.
Graphic abstract
The main purpose of this study is to investigate how destination authenticity interacts with place attachment and loyalty and whether self-authenticity moderate these relationships at a traditional ...village-Luoyi, Hainan, China. Based on the literature, four facets of destination authenticity are investigated: object-based authenticity, intrapersonal authenticity, transformative experience and interpersonal authenticity. The empirical findings indicate that object-based authenticity, intrapersonal authenticity, transformative experience lead tourists not only to be emotionally attached to a destination but, to enhance destination loyalty. Object-based authenticity and intrapersonal authenticity led to higher place attachment for consumers high in self-authenticity. With the empirical results, theoretical and managerial implications are discussed.
We perform decoy-state quantum key distribution between a low-Earth-orbit satellite and multiple ground stations located in Xinglong, Nanshan, and Graz, which establish satellite-to-ground secure ...keys with ∼kHz rate per passage of the satellite Micius over a ground station. The satellite thus establishes a secure key between itself and, say, Xinglong, and another key between itself and, say, Graz. Then, upon request from the ground command, Micius acts as a trusted relay. It performs bitwise exclusive or operations between the two keys and relays the result to one of the ground stations. That way, a secret key is created between China and Europe at locations separated by 7600 km on Earth. These keys are then used for intercontinental quantum-secured communication. This was, on the one hand, the transmission of images in a one-time pad configuration from China to Austria as well as from Austria to China. Also, a video conference was performed between the Austrian Academy of Sciences and the Chinese Academy of Sciences, which also included a 280 km optical ground connection between Xinglong and Beijing. Our work clearly confirms the Micius satellite as a robust platform for quantum key distribution with different ground stations on Earth, and points towards an efficient solution for an ultralong-distance global quantum network.
•A method is designed to extract driving behaviour features and predict risk levels.•Massive driving behaviour features are extracted from real vehicle trajectory data.•Key features are identified by ...feature importance ranking and recursive elimination.•XGBoost can achieve satisfactory results of behaviour-based crash risk prediction.
This study designs a framework of feature extraction and selection, to assess vehicle driving and predict risk levels. The framework integrates learning-based feature selection, unsupervised risk rating, and imbalanced data resampling. For each vehicle, about 1300 driving behaviour features are extracted from trajectory data, which produce in-depth and multi-view measures on behaviours. To estimate the risk potentials of vehicles in driving, unsupervised data labelling is proposed. Based on extracted risk indicator features, vehicles are clustered into various groups labelled with graded risk levels. Data under-sampling of the safe group is performed to reduce the risk-safe class imbalance. Afterwards, the linkages between behaviour features and corresponding risk levels are built using XGBoost, and key features are identified according to feature importance ranking and recursive elimination. The risk levels of vehicles in driving are predicted based on key features selected. As a case study, NGSIM trajectory data are used in which four risk levels are clustered by Fuzzy C-means, 64 key behaviour features are identified, and an overall accuracy of 89% is achieved for behaviour-based risk prediction. Findings show that this approach is effective and reliable to identify important features for driving assessment, and achieve an accurate prediction of risk levels.
Cancer stem cells (CSCs) are cancer‐initiating cells that are not only a source of tumorigenesis but also the cause of tumour progression, metastasis and therapy resistance. EBV‐associated gastric ...cancer (EBVaGC) is a distinct subtype of gastric cancer with unique clinicopathological and molecular features. However, whether CSCs exist in EBVaGC, and the tumorigenic mechanism of EBV, remains unclear. Here, NOD/SCID mice were injected subcutaneously with the EBVaGC cell line SNU719 and treated with 5‐fluorouracil weekly. Successive generations of xenografts yielded a highly malignant EBVaGC cell line, SNU‐4th, which displays properties of CSCs and mainly consists of CD44+CD24− cells. In SNU‐4th cells, an EBV‐encoded circRNA, ebv‐circLMP2A, expression increased and plays crucial roles in inducing and maintaining stemness phenotypes through targeting miR‐3908/TRIM59/p53 axis. Additionally, high expression of ebv‐circLMP2A is significantly associated with metastasis and poor prognosis in patients with EBVaGC. These findings not only provide evidence for the existence of CSCs in EBVaGC and elucidate the pathogenic mechanism of ebv‐circLMP2A in EBVaGC, but also provide a promising therapeutic target for EBVaGC.
Synopsis
The circRNA LMP2A produced by the Epstein‐Barr virus induces stemness of EBV‐associated gastric cancer cells by attenuating the tumor suppressive effect of the miR‐3908/TRIM59/p53 axis, thereby promoting metastasis and tumor progression.
Cells with properties of cancer stem cells were isolated form EBV‐associated gastric cancer (EBVaGC).
The levels of an EBV‐encoded circRNA (ebv‐circLMP2A) are significantly increased in EBVaGC.
ebv‐circLMP2A has crucial roles in inducing and maintaining cancer stemness in EBVaGC.
High expression of ebv‐circLMP2A is significantly associated with metastasis and poor prognosis in EBVaGC patients.
The circRNA LMP2A produced by the Epstein‐Barr virus induces stemness of EBV‐associated gastric cancer cells by attenuating the tumor suppressive effect of the miR‐3908/TRIM59/p53 axis, thereby promoting metastasis and tumor progression.
We perform a systematic exploration of the possible doubly charmed molecular pentaquarks composed of Σc(⁎)D(⁎) with the one-boson-exchange potential model. After taking into account the S−D wave ...mixing and the coupled channel effects, we predict several possible doubly charmed molecular pentaquarks, which include the ΣcD with I(JP)=1/2(1/2−), Σc⁎D with 1/2(3/2−), and ΣcD⁎ with 1/2(1/2−), 1/2(3/2−). The ΣcD state with 3/2(1/2−) and ΣcD⁎ state with 3/2(1/2−) may also be suggested as candidates of doubly charmed molecular pentaquarks. The ΣcD and Σc⁎D states can be searched for by analyzing the ΛcDπ invariant mass spectrum of the bottom baryon and B meson decays. The ΣcD⁎ states can be searched for in the invariant mass spectrum of ΛcD⁎π, ΛcDππ and ΛcDπγ. Since the width of Σc⁎ is much larger than that of D⁎, Σc⁎D→ΛcDπ will be the dominant decay mode. We sincerely hope these candidates for the doubly charmed molecular pentaqurks will be searched by LHCb or BelleII collaboration in the near future.
Benzoylaconitine (BAC), the main hydrolysate of aconitine, is a lower toxic monoester type alkaloid considered as the pharmacodynamic constituent in Aconitum species. In this study, the effects and ...mechanisms of BAC on production of inflammatory cytokines interleukin (IL)-6 and IL-8 were investigated in IL-1β-stimulated human synovial SW982 cells. The SW982 cells were incubated with BAC (0, 5 and 10 µM) before stimulating with IL-1β (10 ng/mL). The results revealed that BAC suppressed gene and protein expression of IL-6 and IL-8 induced by IL-1β. BAC decreased activation of mitogen-activated protein kinase (MAPK) and phosphorylation of Akt. BAC also inhibited degradation of inhibitor of kappaB (IκB)-α, phosphorylation and nuclear transposition of p65 protein. The results demonstrate that BAC exerts an anti-inflammatory effect dependent on MAPK, Akt and nuclear factor-κB (NF-κB) pathways in human synovial cells stimulated with IL-1β, suggesting that BAC may be exploited as a potential therapeutic agent for rheumatoid arthritis (RA) treatment.
CRISPR‐based biosensing technology has been emerging as a revolutionary diagnostic tool for many disease‐related biomarkers. In particular, RspCas13d, a newly identified RNA‐guided Cas13d ...ribonuclease derived from Ruminococcus sp., has shown great promise for accurate and sensitive detection of RNA due to its RNA sequence‐specific recognition and robust collateral trans‐cleavage activity. However, its diagnostic utility is limited to detecting nucleic‐acid‐related biomarkers. To address this limitation, herein we present a proof‐of‐concept demonstration of a target‐responsive CRISPR‐Cas13d sensing system for protein biomarkers. This system was rationally designed by integrating a dual‐aptamer‐based transcription amplification strategy with CRISPR‐Cas13d (DATAS‐Cas13d), in which the protein binding initiates in‐vitro RNA transcription followed by the activation of RspCas13d. Using a short fluorescent ssRNA as the signal reporter and cardiac troponin I (cTnI) as the model analyte, the DATAS‐Cas13d system showed a wide linear range, low detection limit, and high specificity for the detection of cTnI in buffer and human serum. Thanks to the facile integration of various bioreceptors into the DATAS‐Cas13d system, the method could be adapted to detecting a broad range of clinically relevant protein biomarkers, and thus broaden the medical applications of Cas13d‐based diagnostics.
Transcriptional immuno‐CRISPR: A target‐responsive CRISPR‐Cas13d sensing system for proteins was rationally designed by dual‐aptamer‐based target recognition and binding‐induced in‐vitro transcription to trigger Cas13d‐mediated signal amplification. Such a dual recognition/amplification mode enables protein detection with high specificity and sensitivity, expanding CRISPR‐Cas13d diagnostic toolbox significantly.
Visible‐light driven photoconversion of CO2 into energy carriers is highly important to the natural carbon balance and sustainable development. Demonstrated here is the adenine‐dependent CO2 ...photoreduction performance in green biomimetic metal–organic frameworks. Photocatalytic results indicate that AD‐MOF‐2 exhibited a very high HCOOH production rate of 443.2 μmol g−1 h−1 in pure aqueous solution, and is more than two times higher than that of AD‐MOF‐1 (179.0 μmol g−1h−1) in acetonitrile solution. Significantly, experimental and theoretical evidence reveal that the CO2 photoreduction reaction mainly takes place at the aromatic nitrogen atom of adenine molecules through a unique o‐amino‐assisted activation rather than at the metal center. This work not only serves as an important case study for the development of green biomimetic photocatalysts used for artificial photosynthesis, but also proposes a new catalytic strategy for efficient CO2 photoconversion.
Eco‐friendly terms: Two biomimetic metal–organic frameworks (MOFs) were assembled with eco‐friendly components and used as photocatalysts for CO2‐to‐HCOOH conversion. One of the synthesized MOFs exhibited a very high HCOOH production rate of 443.2 μmol g−1 h−1 in pure aqueous solution.
With ethylene glycol as a green solvent, a general transition metal‐free photocatalytic system using 9‐mesityl‐10‐methylacridinium perchlorate (Acr+−Mes ⋅ ClO4−) as catalyst was developed for the ...synthesis of sulfone‐containing heterocycles including thioflavones, oxindoles, and quinoline‐2,4(1H,3H)‐diones through the cascade sulfonation/cyclization reactions under the irradiation of blue light at room temperature.
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