1,335 research outputs found

    The two-pseudoscalar-meson decay of χcJ\chi_{cJ} with twist-3 corrections

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    The decays of χcJ→π+π−,K+K−\chi_{cJ} \to \pi^+\pi^-, K^+K^- (J=0,2)(J=0,2) are discussed within the standard and modified hard scattering approach when including the contributions from twist-3 distribution amplitudes and wave functions of the light pseudoscalar meson. A model for twist-2 and twist-3 distribution amplitudes and wave functions of the pion and kaon with BHL prescription are proposed as the solution to the end-point singularities. The results show that the contributions from twist-3 parts are actually not power suppressed comparing with the leading-twist contribution. After including the effects from the transverse momentum of light meson valence-quark state and Sudakov factors, the decay widths of the χcJ\chi_{cJ} into pions or kaons are comparable with the their experimental data.Comment: 31 pages, 5 figures, 3 table

    Evolution of pairing from weak to strong coupling on a honeycomb lattice

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    We study the evolution of the pairing from weak to strong coupling on a honeycomb lattice by Quantum Monte Carlo. We show numerical evidence of the BCS-BEC crossover as the coupling strength increases on a honeycomb lattice with small fermi surface by measuring a wide range of observables: double occupancy, spin susceptibility, local pair correlation, and kinetic energy. Although at low energy, the model sustains Dirac fermions, we do not find significant qualitative difference in the BCS-BEC crossover as compared to those with an extended Fermi surface, except at weak coupling, BCS regime.Comment: 5 page

    Determination of Methylated CpG Sites in the Promoter Region of Catechol-O-Methyltransferase (COMT) and their Involvement in the Etiology of Tobacco Smoking

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    We previously reported that catechol-O-methyltransferase (COMT) is significantly associated with nicotine dependence (ND) in humans. In this study, we examined whether there exists any difference in the extent of methylation of CpG dinucleotides in the promoter region of COMT in smokers and non-smokers by analyzing the methylation status of cytosines at 33 CpG sites through direct sequencing of bisulfite-treated DNA (N = 50 per group). The cytosine was methylated at 13 of 33 CpG sites, and two of these sites showed significant differences between smokers and matched non-smoker controls. Specifically, in the −193 CpG site, the degree of methylation was 19.1% in smokers and 13.2% in non-smokers (P < 0.01). This finding was confirmed by methylation-specific PCR using an additional 100 smoker and 100 non-smoker control samples, which showed the degree of methylation to be 22.2% in smokers and 18.3% in non-smokers (P < 0.01). For the −39 CpG site, the degree of methylation was 9.2% in smokers, whereas no methylation was found in non-smoker controls. Together, our findings provide the first molecular explanation at the epigenetic level for the association of ND with methylation of the COMT promoter, implying that methylation plays a role in smoking dependence

    On Estimation of Fully Entangled Fraction

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    We study the fully entangled fraction (FEF) of arbitrary mixed states. New upper bounds of FEF are derived. These upper bounds make complements on the estimation of the value of FEF. For weakly mixed quantum states, an upper bound is shown to be very tight to the exact value of FEF.Comment: 8 pages, 2 figure

    A Weighted U Statistic for Genetic Association Analyses of Sequencing Data

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    With advancements in next generation sequencing technology, a massive amount of sequencing data are generated, offering a great opportunity to comprehensively investigate the role of rare variants in the genetic etiology of complex diseases. Nevertheless, this poses a great challenge for the statistical analysis of high-dimensional sequencing data. The association analyses based on traditional statistical methods suffer substantial power loss because of the low frequency of genetic variants and the extremely high dimensionality of the data. We developed a weighted U statistic, referred to as WU-seq, for the high-dimensional association analysis of sequencing data. Based on a non-parametric U statistic, WU-SEQ makes no assumption of the underlying disease model and phenotype distribution, and can be applied to a variety of phenotypes. Through simulation studies and an empirical study, we showed that WU-SEQ outperformed a commonly used SKAT method when the underlying assumptions were violated (e.g., the phenotype followed a heavy-tailed distribution). Even when the assumptions were satisfied, WU-SEQ still attained comparable performance to SKAT. Finally, we applied WU-seq to sequencing data from the Dallas Heart Study (DHS), and detected an association between ANGPTL 4 and very low density lipoprotein cholesterol

    Disruption of mesoderm formation during cardiac differentiation due to developmental exposure to 13-cis-retinoic acid.

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    13-cis-retinoic acid (isotretinoin, INN) is an oral pharmaceutical drug used for the treatment of skin acne, and is also a known teratogen. In this study, the molecular mechanisms underlying INN-induced developmental toxicity during early cardiac differentiation were investigated using both human induced pluripotent stem cells (hiPSCs) and human embryonic stem cells (hESCs). Pre-exposure of hiPSCs and hESCs to a sublethal concentration of INN did not influence cell proliferation and pluripotency. However, mesodermal differentiation was disrupted when INN was included in the medium during differentiation. Transcriptomic profiling by RNA-seq revealed that INN exposure leads to aberrant expression of genes involved in several signaling pathways that control early mesoderm differentiation, such as TGF-beta signaling. In addition, genome-wide chromatin accessibility profiling by ATAC-seq suggested that INN-exposure leads to enhanced DNA-binding of specific transcription factors (TFs), including HNF1B, SOX10 and NFIC, often in close spatial proximity to genes that are dysregulated in response to INN treatment. Altogether, these results identify potential molecular mechanisms underlying INN-induced perturbation during mesodermal differentiation in the context of cardiac development. This study further highlights the utility of human stem cells as an alternative system for investigating congenital diseases of newborns that arise as a result of maternal drug exposure during pregnancy

    The electro production of d* dibaryon

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    d∗d^* dibaryon study is a critical test of hadron interaction models. The electro production cross sections of ed→ed∗ed\to ed^* have been calculated based on the meson exchange current model and the cross section around 30 degree of 1 GeV electron in the laboratory frame is about 10 nb. The implication of this result for the d∗d^* dibaryon search has been discussed.Comment: 12 pages, 12 figures, Late

    Safety and short-term outcomes of esophagectomy after neoadjuvant immunotherapy combined with chemotherapy or chemoradiotherapy for locally advanced esophageal squamous cell cancer:analysis of two phase-II clinical trials

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    Background: Preoperative chemotherapy (CT) or chemoradiotherapy (CRT) show survival benefits in patients with locally advanced esophageal squamous cell carcinoma (ESCC); however, ESCC patients still have a dismal prognosis. We conducted two phase-II, single-armed clinical trials to assess the potential benefits, efficacy, feasibility, and safety of esophagectomy after combining preoperative CT or CRT and neoadjuvant programmed cell death protein 1 (PD-1) inhibitors in the treatment of ESCC. Methods: Patients were included with histologically confirmed ESCC (clinical stage II–IVA according to the American Joint Committee on Cancer 8th staging system) from two phase-II, single-arm trials (NCT04506138 and NCT03940001). Patients underwent two doses of intravenous PD-1 inhibitor (either camrelizumab or sintilimab) every 3 weeks, combined with two cycles of either CT or CRT. The primary endpoint of the study was the safety and short-term outcomes of esophagectomy as measured by the risk of developing complications within 30 days, after the combination of preoperative PD-1 inhibitor and CT or CRT Secondary endpoint was to evaluate the pCR rates (pT0N0), primary tumor pCR rates (pT0), operation time, postoperative stay, and 30-day mortality rate between both groups. Results between both groups were compared using a multivariable log-binomial regression model to obtain the adjusted relative risk ratios (RRs). Results: Between May 2019 and June 2022, 55 patients were included. All patients completed neoadjuvant therapy. Age, sex, performance status, clinical stage, histologic subtype, procedure type, operative time, and blood loss volume were similar between the two groups. The primary tumor pCR rates were 52.9% in the nICRT group and 21.6% in the nICT group (P=0.03), while the postoperative pCR rates were 41.2% in the nICRT group and 21.6% in the nICT group (P=0.19). The minimally invasive surgery rates were 89.2% (33/37) in the nICT group and 94.1% (16/17) in the nICRT group. The risk of developing pulmonary, anastomotic, or other complications were similar between the two groups. Conclusions: Esophagectomy was safe after the addition of the PD-1 inhibitor to preoperative CT or CRT in ESCC neoadjuvant therapies. Follow-up and the exploratory endpoints, including biomarkers analyses, are ongoing.</p

    Versatile Roles of V-ATPases Accessory Subunit Ac45 in Osteoclast Formation and Function

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    Vacuolar-type H+-ATPases (V-ATPases) are macromolecular proton pumps that acidify intracellular cargos and deliver protons across the plasma membrane of a variety of specialized cells, including bone-resorbing osteoclasts. Extracellular acidification is crucial for osteoclastic bone resorption, a process that initiates the dissolution of mineralized bone matrix. While the importance of V-ATPases in osteoclastic resorptive function is well-defined, whether V-ATPases facilitate additional aspects of osteoclast function and/or formation remains largely obscure. Here we report that the V-ATPase accessory subunit Ac45 participates in both osteoclast formation and function. Using a siRNA-based approach, we show that targeted suppression of Ac45 impairs intracellular acidification and endocytosis, both are prerequisite for osteoclastic bone resorptive function in vitro. Interestingly, we find that knockdown of Ac45 also attenuates osteoclastogenesis owing to a reduced fusion capacity of osteoclastic precursor cells. Finally, in an effort to gain more detailed insights into the functional role of Ac45 in osteoclasts, we attempted to generate osteoclast-specific Ac45 conditional knockout mice using a Cathepsin K-Cre-LoxP system. Surprisingly, however, insertion of the neomycin cassette in the Ac45-FloxNeo mice resulted in marked disturbances in CNS development and ensuing embryonic lethality thus precluding functional assessment of Ac45 in osteoclasts and peripheral bone tissues. Based on these unexpected findings we propose that, in addition to its canonical function in V-ATPase-mediated acidification, Ac45 plays versatile roles during osteoclast formation and function
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