30 research outputs found

    Trapping Penguins with Entangled B Mesons

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    The first direct observation of time-reversal (T) violation in the BBˉB\bar{B} system has been reported by the BaBar collaboration, employing the method of Ban~ ⁣\tilde {\rm n}\!uls and Bernab\'eu. Given this, we generalize their analysis of the time-dependent T-violating asymmetry (ATA_{T}) to consider different choices of CP tags for which the dominant amplitudes have the same weak phase. As one application, we find that it is possible to measure departures from the universality of sin(2β)\sin(2\beta) directly. If sin(2β)\sin(2\beta) is universal, as in the Standard Model, the method permits the direct determination of penguin effects in these channels. Our method, although no longer a strict test of T, can yield tests of the sin(2β)\sin(2\beta) universality, or, alternatively, of penguin effects, of much improved precision even with existing data sets.Comment: 11 pages, 2 figures; refs. added; reframed with expanded discussions; version to appear in PLB; Metadata abstract updated onl

    The complete mitochondrial genome of two-belt cardinal and striped cardinalfish Apogonichthyoides taeniatus (Cuvier, 1828)

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    The complete mitochondrial DNA sequence of Apogonichthyoides taeniatus (Cuvier, 1828) is determined. The mitochondrial genome is 17,050 in length and has the same composition and gene order like most other vertebrates. The phylogenetic analysis based on 13 concatenated PCGs nucleotide sequences among 20 species showed that this species has high support with the sister branch Jaydia lineata. Our findings provide useful information for phylogenetic and evolutionary research of Kurtiformes species

    Biosynthesis of Platinum Nanoparticles with Cordyceps Flower Extract: Characterization, Antioxidant Activity and Antibacterial Activity

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    The aim of this work is to develop a green route for platinum nanoparticles (PtNPs) biosynthesized using Cordyceps flower extract and to evaluate their antioxidant activity and antibacterial activity. Different characterization techniques were utilized to characterize the biosynthetic PtNPs. The results showed that PtNPs were spherical particles covered with Cordyceps flower extract. The average particle size of PtNPs in Dynamic Light Scattering was 84.67 ± 5.28 nm, while that of PtNPs in Transmission Electron Microscope was 13.34 ± 4.06 nm. Antioxidant activity of PtNPs was evaluated by DPPH free radical scavenging ability test. The results showed that the antioxidant activity was positively correlated with the concentration of PtNPs, the DPPH scavenging efficiency of PtNPs (0.50–125.00 μg/mL) was 27.77–44.00%. In addition, the morphological changes of four kinds of bacteria (Escherichia coli, Salmonella typhimurium, Bacillus subtilis, Staphylococcus aureus) exposed to PtNPs were observed by scanning electron microscope. The results showed that the antibacterial activity of PtNPs against Gram-negative bacteria was stronger than that of Gram-positive bacteria

    Study of micro-mesoscopic creep damage on mudstone based on stress corrosion model

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    To study the creep minor damage evolution process and creep damage mechanism of mudstone, this paper establishes a numerical model of a two-media triple cementation particle flow procedure of mudstone, reproduces the tender damage destruction process of mudstone under creep based on a parallel bonded stress corrosion model, and explores the macroscopic creep characteristics and minor damage mechanism of mudstone specimens under different stress levels and surrounding pressure conditions. The results show that the intrinsic driving force for creep damage in mudstone is the micro-tensile force generated between non-homogeneous particles of mudstone, and the inter-particle cementation is continuously damaged and deteriorated with increasing time; the stable creep rate of mudstone specimens increases with increasing stress level and decreases with increasing surrounding pressure; high-stress levels diffuse microscopic damage in mudstone by increasing the magnitude of inter-particle microtension and the number of particles generating microtension, manifesting as multiple extensions of microcracks; the enclosing pressure dramatically reduces the creep characteristics by limiting the development of inter-particle micro-tensile forces; the microcrack distribution is more uniform and dispersed under the enclosing pressure conditions. The amount of mutual slip between particles increases

    Increasing meteorological drought under climate change reduces terrestrial ecosystem productivity and carbon storage

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    Plants on land absorb about 30% of the CO2 produced by human activities each year, meaning they have mitigated, to some degree, the global warming impacts of human emissions. However, plants are also vulnerable to climate change. While increases in CO2 may have a "fertilizing effect" and increase plant growth and therefore CO2 absorption, other impacts of climate change, such as increasingly frequent and severe droughts, will harm plant growth. In this work, we show that, if the future is powered by fossil-fueled development and CO2 emissions continue to increase, the end of the century will see a 3.5-fold increase in the loss of vegetation productivity due to droughts, especially in cropland. Our results suggest that the "buffering" impact of plants on human CO2 emissions cannot be counted on in an increasingly warm planet and emphasize the importance of greenhouse gas mitigation for vegetation and cropland productivity

    Chidamide Reverses Fluzoparib Resistance in Triple-Negative Breast Cancer Cells

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    Poly (ADP-ribose) polymerase inhibitor (PARPi) resistance is a new challenge for antitumor therapy. The purpose of this study was to investigate the reversal effects of chidamide on fluzoparib resistance, a PARPi, and its mechanism of action. A fluzoparib-resistant triple-negative breast cancer (TNBC) cell line was constructed, and the effects of chidamide and fluzoparib on drug-resistant cells were studied in vitro and in vivo. The effects of these drugs on cell proliferation, migration, invasiveness, the cell cycle, and apoptosis were detected using an MTT assay, wound-healing and transwell invasion assays, and flow cytometry. Bioinformatics was used to identify hub drug resistance genes and Western blots were used to assess the expression of PARP, RAD51, MRE11, cleaved Caspase9, and P-CDK1. Xenograft models were established to analyze the effects of these drugs on nude mice. In vivo results showed that chidamide combined with fluzoparib significantly inhibited the proliferation, migration, and invasiveness of drug-resistant cells and restored fluzoparib sensitivity to drug-resistant cells. The combination of chidamide and fluzoparib significantly inhibited the expression of the hub drug resistance genes RAD51 and MRE11, arrested the cell cycle at the G2/M phase, and induced cell apoptosis. The findings of this work show that chidamide combined with fluzoparib has good antineoplastic activity and reverses TNBC cell resistance to fluzoparil by reducing the expression levels of RAD51 and MRE11

    The Synergistic Effects of SHR6390 Combined With Pyrotinib on HER2+/HR+ Breast Cancer

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    HER2+/HR+ breast cancer is a special molecular type of breast cancer. Existing treatment methods are prone to resistance; "precision treatment" is necessary. Pyrotinib is a pan-her kinase inhibitor that can be used in HER2-positive tumors, while SHR6390 is a CDK4/6 inhibitor that can inhibit ER+ breast cancer cell cycle progression and cancer cell proliferation. In cancer cells, HER2 and CDK4/6 signaling pathways could be nonredundant; co-inhibition of both pathways by combination of SHR6390 and pyrotinib may have synergistic anticancer activity on HER2+/HR+ breast cancer. In this study, we determined the synergy of the two-drug combination and underlying molecular mechanisms. We showed that the combination of SHR6390 and pyrotinib synergistically inhibited the proliferation, migration, and invasion of HER2+/HR+ breast cancer cells in vitro. The combination of two drugs induced G1/S phase arrest and apoptosis in HER2+/HR+ breast cancer cell lines. The combination of two drugs prolonged the time to tumor recurrence in the xenograft model system. By second-generation RNA sequencing technology and enrichment analysis of the pyrotinib-resistant cell line, we found that FOXM1 was associated with induced resistance to HER2-targeted therapy. In HER2+/HR+ breast cancer cell lines, the combination of the two drugs could further reduce FOXM1 phosphorylation, thereby enhancing the antitumor effect to a certain extent. These findings suggest that SHR6390 combination with pyrotinib suppresses the proliferation, migration, and invasion of HER2+/HR+ breast cancers through regulation of FOXM1

    Increased risk of flash droughts with raised concurrent hot and dry extremes under global warming

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    Abstract Flash droughts pose large threats to crop yields and ecosystem services due to their sudden onset and rapid intensification, arousing wide public concern in a warming climate. Their long-term characteristics of change, underlying mechanisms, and especially potential impacts on agriculture, forests, and populations at a global scale, however, remain largely unknown. We used in situ observations, two observation-based global reanalysis data sets, and 22 Earth system models to determine that flash droughts are shifting toward more frequent, accelerated-onset, and longer duration. These changes increased the exposure of agricultural areas, forested areas, and populations to flash droughts by 20.3%, 17.1%, and 30.0%, respectively, during 2001–2020 compared to 1981–2000, with a disproportionate increase in integrated risks across the Amazon Basin and eastern and southern Asia. The increase in concurrent hot and dry climatic conditions driven by warming has been mostly responsible for enabling and intensifying flash droughts over large regions. State-of-the-art Coupled Model Intercomparison Project Phase 6 (CMIP6) models, however, failed to identify the acceleration of the onset time of flash droughts and widely underestimated the occurrence of flash droughts that are driven only by precipitation deficits or by heat waves, probably because they misrepresent the dependence between precipitation and temperature and underestimate the sensitivity of soil moisture to temperature and precipitation at short timescales (e.g., 5 days). These syntheses comprehensively advance our understanding of the characteristics and impacts of flash droughts but also highlight that the CMIP6 models need to be validated to represent the correct covariability between climatic variables at short timescales to provide more reliable projections of flash droughts
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