26 research outputs found

    Simultaneous Horizontal and Vertical Oscillation of a Quiescent Filament observed by CHASE and SDO

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    In this paper, we present the imaging and spectroscopic observations of the simultaneous horizontal and vertical large-amplitude oscillation of a quiescent filament triggered by an EUV wave on 2022 October 02. Particularly, the filament oscillation involved winking phenomenon in Ha images and horizontal motions in EUV images. Originally, a filament and its overlying loops across AR 13110 and 13113 erupted with a highly inclined direction, resulting in an X1.0 flare and a non-radial CME. The fast lateral expansion of loops excited an EUV wave and the corresponding Moreton wave propagating northward. Once the EUV wavefront arrived at the quiescent filament, the filament began to oscillate coherently along the horizontal direction and the winking filament appeared concurrently in Ha images. The horizontal oscillation involved an initial amplitude of 10.2 Mm and a velocity amplitude of 46.5 km/s, lasting for 3 cycles with a period of 18.2 minutes and a damping time of 31.1 minutes. The maximum Doppler velocities of the oscillating filament are 18 km/s (redshift) and 24 km/s (blueshift), which was derived from the spectroscopic data provided by CHASE/HIS. The three-dimensional velocity of the oscillation is determined to be 50 km/s at an angle of 50 to the local photosphere plane. Based on the wave-filament interaction, the minimum energy of the EUV wave is estimated to be 2.7 10 20 J. Furthermore, this event provides evidence that Moreton wavesshould be excited by the highly inclined eruptions

    Observational signature of continuously operating drivers of decayless kink oscillation

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    Decayless kink oscillations, which are nearly omnipresent in the solar corona, are believed to be driven by continuously operating energy supply. In this letter, we investigate an external continuous excitation of an apparent decayless oscillation during an X1.1 flare on June 20, 2023 (SOL2023-06-20T16:42).The decayless kink oscillation was identified in the coronal loop at extreme ultraviolet (EUV) wavelengths and the associated flare quasi-periodic pulsations (QPPs) were simultaneously observed in passbands of hard X-ray (HXR), microwave, and ultraviolet (UV) emissions. The kink oscillation is detected as a transverse oscillation of the coronal loop, which reveals five apparent cycles with an average period of about 130-10 s. The oscillation amplitude does not show any significantly decay, suggesting a decayless oscillation. At the same time, the solar flare occurs in the vicinity of the oscillating loop and exhibits five main pulses in HXR, microwave, and UV emissions, which could be regarded as flare QPPs. They have similar periods of about 100-130 s, which may indicate successive and repetitive energy releases during the flare impulsive phase. The peak of each loop oscillation cycle appears to follow the pulse of the QPPs, suggesting that the transverse oscillation is closely associated with flare QPPs. Our observations support the scenario where the repetitive energy released following flare QPPs could be invoked as external, continuously operating drivers of the apparent decayless kink oscillation.Comment: accepted by A&

    The Effects of Government Licensing on E-commerce: Evidence from Alibaba

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    Inspired by the call in Demsetz’s “Barriers to Entry” for assessing the implications of occupational licensing, we examine how the 2015 Food Safety Law (FSL) affects e-commerce in China. The FSL requires most food sellers on e-commerce platforms to obtain off-line licenses. On the basis of its gradual rollout on Alibaba, we find that larger and more-reputable sellers display an FSL license earlier, and buyers are more willing to transact with a licensed seller, especially if the seller is younger and unestablished. This suggests that the license is informative. Market-wide, the average quality of surviving sellers has improved and seller concentration has increased since the FSL. The platform’s gross merchandise value for food did not decline, nor did the average sales price increase 1 year into full enforcement. This suggests that the FSL does not hamper long-term market performance, probably because it enhances seller quality and market transparency

    Food-Derived Pharmacological Modulators of the Nrf2/ARE Pathway: Their Role in the Treatment of Diseases

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    Oxidative stress, which refers to unbalanced accumulation of reactive oxygen species (ROS) levels in cells, has been linked to acute and chronic diseases. Nuclear factor erythroid 2-related factor 2/antioxidant response element (Nrf2/ARE) pathway plays a vital role in regulating cytoprotective genes and enzymes in response to oxidative stress. Therefore, pharmacological regulation of Nrf2/ARE pathway is an effective method to treat several diseases that are mainly characterized by oxidative stress and inflammation. Natural products that counteract oxidative stress by modulating Nrf2 have contributed significantly to disease treatment. In this review, we focus on bioactive compounds derived from food that are Nrf2/ARE pathway regulators and describe the molecular mechanisms for regulating Nrf2 to exert favorable effects in experimental models of diseases

    MiR-146a Aggravates LPS-Induced Inflammatory Injury by Targeting CXCR4 in the Articular Chondrocytes

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    Background/Aims: Osteoarthritis (OA) as a degenerative disease is a major problem in ageing populations. To better understand the molecular mechanisms in the pathogenesis of OA, this study explored the role of microRNA (miR)-146a in the articular chondrocytes. Methods: The articular chondrocyte line ATDC5 was used to simulate inflammatory injury by LPS administration in vitro. Cell viability, apoptosis, mRNA expressions and productions of inflammatory factors were assessed, respectively. Mir-146a and Cxcr4 mRNA expressions were measured by qRT-PCR. Targeting effect of miR-146a on Cxcr4 3’UTR was assessed by luciferase activity analysis. Protein expression levels of CXCR4 and main factors in PI3K/AKT, Wnt/β-catenin signal pathways were measured by western blotting. Results: LPS exposure suppressed cell viability, prompted apoptosis of ATDC5 cells, and stimulated expression and release of inflammatory factors. MiR-146a was upregulated in LPS-induced cells. Overexpression of miR-146a further aggravated LPS-induced inflammatory injury, while it was reduced after miR-146a was knocked down. CXCR4 expression was negatively regulated by miR-146a. CXCR4 was a direct target of miR-146a and thus involved in regulatory effect of miR-146a on the injured chondrocytes, which was also related with phosphorylation levels of PI3K/AKT and expressions of Wnt/β-catenin signal factors. Conclusion: miR-146a promoted inflammatory response of articular chondrocytes via targeting CXCR4 and suppressing CXCR4 expression. Overexpression of CXCR4 could attenuate the inflammatory injury. Our findings provided novel evidence which might be useful for further studies exploring therapeutic approaches for OA via targeting miR-146a

    Ovarian microcystic stromal tumor with omental metastasis: the first case report and literature review

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    Abstract Background Microcystic stromal tumor (MCST) of the ovary is an extremely rare subtype of sex cord-stromal neoplasm first described by Irving and Young in 2009. Tumors from all previously reported cases (fewer than 40 total) were benign, but one was a case of ovarian MCST that reoccurred. Case presentation Herein, we present a unique single case of ovarian MCST with omental metastasis in a 47-year-old Chinese female along with its histologic and immunohistochemical profile and genetic alterations. The tumor exhibited the previously described classic microscopic features and immunoprofiles of MCST. The tumorlet in the omentum presented the same histological structures and characteristically expressed β-catenin protein (localized in the nucleus). Molecular analysis identified a point mutation (c.98C > G) in exon 3 of CTNNB1. Conclusions To the best of our knowledge, no such report has been documented for ovarian MCST with omental metastasis. The study may provide new insights into the tumor biology of MCST and provide a better understanding of this rare entity

    Sedimentary Architecture Analysis of Deltaic Sand Bodies Using Sequence Stratigraphy and Seismic Sedimentology: A Case Study of Jurassic Deposits in Zhetybay Oilfield, Mangeshrak Basin, Kazakhstan

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    Three-dimensional (3D) seismic data and well log data were used to investigate the sandstone architecture of the Middle Jurassic deltaic reservoirs of the Zhetybay Oilfield, Mangeshrak Basin, Kazakhstan. The base-level cycles of different scales were identified and divided using well log and 3D seismic data. Five types of sedimentary boundaries were identified in the mouth bar sandstones. The boundaries divide single mouth bars. Vertically, the spatial distribution of sand bodies can be divided into superposed, spliced, and isolation modes. Laterally, contact modes can be divided into superposition, lateral, and isolation modes. We found that the base-level cycle controls the evolution of the delta front sand body architecture. In the early decline or late rise of the base-level cycle, the superimposed or spliced modes dominate the sand body. By contrast, the lateral or isolation modes dominate the sand body in the late decline or early rise of the base-level cycle. This paper proposes an architecture model of the delta front sand bodies controlled by the base-level cycle. The spatial distribution and morphological variation of deltaic sand bodies could be linked to the base-level cycles

    The complete mitochondrial genome of the hybrid offspring Epinephelus awoara♀ × Epinephelus tukula♂

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    The complete mitochondrial genome of hybrid grouper from Epinephelus awoara (♀) ×E. tukula (♂) was obtained by PCR amplification. The circular genome was 16,801 bp in length, consisting of 13 protein-coding genes, 22 transfer RNA genes, 2 ribosomal RNA genes, and a control region (D-loop region). The overall base composition was as follows: A: 28.46%, T: 27.27%, C: 27.27%, G: 16.49%. The new results may provide valuable data for the genetic and taxonomic research on artificial hybrid grouper

    Characterization of the complete mitochondrial genome of the hybrid grouper (Cromileptes altivelis♀ × Epinephelus tukula♂) with phylogenetic consideration

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    Here we isolated and characterized the complete mitochondrial genome of the hybrid grouper (Cromileptes altivelis♀ × Epinephelus tukula♂). It is 16,503 bp long and contains 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes, and a control region. The nucleotide composition is 29.08% of A, 29.03% of C, 15.66% of G and 26.23% of T, with 55.31% A + T. The phylogenetic analysis by neighbor-joining (NJ) method reveals that the hybrid offspring has a closer relationship to C. altivelis
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