1,479 research outputs found

    Differential cross-section measurements for four-lepton production and implications for new physics

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    This thesis describes the analysis design and results of the ATLAS four-lepton measurement, using 139 fb−1 of data collected in 13 TeV proton-proton collisions at the Large Hadron Collider. The measurement is designed for maximal model-independence and inclusivity. Defined solely in terms of the final state particles, any process leading to the creation of four or more leptons is considered to be a part of the signal. The results are presented in the form of inclusive and fiducial differential cross-sections, and are corrected for detector effects via an iterative Bayesian technique. The measurement is compared to state- of-the-art Standard Model predictions, and the two are found to be consistent. Secondly, two re-interpretation studies are presented where existing precision fiducial measurements, including the aforementioned four-lepton measurement, are used to set constraints on two beyond the Standard Model theories. The first is a generic model of vector-like quarks, and the second is a model with a gauged and spontaneously broken B − L symmetry. These studies are conducted using the CONTUR re-interpretation toolkit. The derived limits are competitive with existing ATLAS limits, and exclude previously unexplored regions of parameter space

    Clinical observation on the treatment of glaucoma with cataract through triple surgery

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    AIM: To observe the therapeutic effect of triple surgery in the treatment of glaucoma with cataract at different stages.<p>METHODS: Totally 31 patients(55 eyes)with glaucoma and cataract were treated with phacoemulsification, lens implantation and trabeculectomy. Preoperation and postoperation of visual acuity, intraocular pressure, filtering bleb and postoperation complications were observed.<p>RESULTS: After 6mo postoperation, the vision was significantly improved. The intraocular pressure was controlled in normal range and filtering bleb was good. There was a little complications after operation.<p>CONCLUSION: Phacoemulsification intraocular lens implantation with anti-glaucoma establishes new aqueous humor outflow. It can effectively decrease intraocular pressure, deepen anterior chamber and improve vision, reduce all kinds of complications after simple glaucoma surgery

    Quantitative Identification of Adulterated Sichuan Pepper Powder by Near-Infrared Spectroscopy Coupled with Chemometrics

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    Sichuan pepper is a traditional and important flavoring of Chinese cuisine. It has attracted increasing interest in recent years owning to its unique taste and aroma. However, some cheap adulterants have been illegally found in Sichuan pepper powder in the market due to merchants trying to cut costs and gain an extra profit. In order to determine the compositions of Sichuan pepper powder quickly and effectively, a direct detection method using near-infrared (NIR) spectroscopy has been developed. 462 samples of adulterated Sichuan pepper powder mixed with different amounts of wheat bran, rice bran, corn flour, and rosin powder were studied. The NIR spectra data was studied using partial least squares (PLS) analysis. The method was found to be capable of predicting the compositions of adulterated Sichuan pepper powder. The determination coefficients of prediction set (Rp2) with the best pretreatments were 0.971 for Sichuan pepper powder, 0.948 for rice bran, 0.969 for wheat bran, 0.967 for corn flour, and 0.994 for rosin powder, respectively. The standard errors of prediction (SEP) were 2.81%, 2.38%, 3.19%, 2.46%, and 1.10%, respectively. The results showed that NIR spectroscopy with chemometrics is a rapid and nondestructive tool for the quantitative analysis of adulterated Sichuan pepper powder

    Synaptophysin Expression in Rat Retina Following Acute High Intraocular Pressure

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    In response to injury, synapse alteration may occur earlier than the changes in the cell body of neurons. Although retinal ganglion cell death and thinning of the inner part of retina were found after acute high intraocular pressure (HIOP), the structural and functional changes of synapses in the retina remain unknown. In the present study, we investigated the protein and mRNA expression of synaptophysin (SYN), an important molecule closely related to synaptic activities, synaptogenesis and synaptic plasticity. In addition, we also studied the ultrastructural changes of the retinal synapses. We found that (1) synaptophysin was upregulated transiently at both protein and mRNA level following HIOP; (2) broadened distribution of synaptophysin protein was present within the outer nuclear layer at the early stage following HIOP; (3) in the outer nuclear layer bouton-like vesicle-containing structures were observed by electron microscopy. This data suggested that, besides degeneration, synapses in rat retina may undergo regenerative events following HIOP

    Genetic characterization and passage instability of a novel hybrid virulence plasmid in a ST23 hypervirulent Klebsiella pneumoniae

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    Hypervirulent variants of Klebsiella pnuemoniae (hvKP), which causes life-threatening infections, is a global priority pathogen and frequently harbours virulence plasmids. The virulence plasmids have emerged as the predominant vehicles carrying the major pathogenic determinants of hypermucoviscosity and hypervirulence phenotypes. In the present study, we characterized a novel virulence plasmid in AP8555, an ST23 hvKP strain, which induced a metastatic infection and fatal septic shock in a critically ill patient. The serum killing assay, the quantitative biofilm formation assay, the G.mellonella infection model, and the mouse lethality assay demonstrated that AP8555 was almost as virulent as the hvKP strain NUTH-K2044. The plasmid pAP855 could be conjugated to Klebsiella quasipneumoniae ATCC700603 and E. coli J53 at a frequency of 7.2× 10−5 and 8.7× 10−7, respectively. Whole-genome sequencing and bioinformatics analysis confirmed that the plasmid was novel, clustered to the incompatibility type of IncHI1B/IncFIB/IncFII and presented high similarity to the pK2044 plasmid. In contrast, a 130-kb large-fragment insertion was observed on the plasmid, which introduced a genetic hybrid zone with multiple conjugation-related genes of type IV secretion systems (T4SS) and CcdAB toxin-antitoxin systems (TAS) to the plasmid. In the transconjugants, the presence of pAP855 had a negative impact on bacterial fitness, but enhancing the virulence-associated phenotypes. In vitro evolution experiments showed that pAP855 in the transconjugants could not be stably inherited after 10 days of passage. Our study not only reports a novel hybrid plasmid but also highlights the putative pathway of conjugative virulence plasmid formation and evolution by means of genetic rearrangement through sequence insertion. These findings indicate that structural versatility could contribute to the dissemination of cointegrate virulence plasmid, although the plasmid incurred a fitness cost. Therefore, continuous monitoring the acquisition of conjugative virulence plasmids may have critical value for plasmid research and increase awareness of hvKP

    Catechol-chitosan/polyacrylamide hydrogel wound dressing for regulating local inflammation

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    Chronic wounds and the accompanying inflammation are ongoing challenges in clinical treatment. They are usually accompanied by low pH and high oxidative stress environments, limiting cell growth and proliferation. Ordinary medical gauze has limited therapeutic effects on chronic wounds, and there is active research to develop new wound dressings. The chitosan hydrogel could be widely used in biomedical science with great biocompatibility, but the low mechanical properties limit its development. This work uses polyacrylamide to prepare double-network (DN) hydrogels based on bioadhesive catechol-chitosan hydrogels. Cystamine and N, N′-Bis(acryloyl)cystamine, which can be cross-linking agents with disulfide bonds to prepare redox-responsive DN hydrogels and pH-responsive nanoparticles (NPs) prepared by acetalized cyclodextrin (ACD) are used to intelligently release drugs against chronic inflammation microenvironments. The addition of catechol groups and ACD-NPs loaded with the Resolvin E1 (RvE1), promotes cell adhesion and regulates the inflammatory response at the wound site. The preparation of the DN hydrogel in this study can be used to treat and regulate the inflammatory microenvironment of chronic wounds accurately. It provides new ideas for using inflammation resolving factor loaded in DN hydrogel of good biocompatibility with enhanced mechanical properties to intelligent regulate the wound inflammation and promote the wound repaired
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