845 research outputs found

    Phonon Effects on Spin-Charge Separation in One Dimension

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    Phonon effects on spin-charge separation in one dimension are investigated through the calculation of one-electron spectral functions in terms of the recently developed cluster perturbation theory together with an optimized phonon approach. It is found that the retardation effect due to the finiteness of phonon frequency suppresses the spin-charge separation and eventually makes it invisible in the spectral function. By comparing our results with experimental data of TTF-TCNQ, it is observed that the electron-phonon interaction must be taken into account when interpreting the ARPES data.Comment: 5 pages, 5 figures, minor differences with the published version in Physical Review Letter

    Lack of EGFR mutations benefiting gefitinib treatment in adenocarcinoma of esophagogastric junction

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    <p>Abstract</p> <p>Background</p> <p>The epidermal growth factor receptor (EGFR) inhibitor, gefitinib, has been reported to successfully treat advanced non-small cell lung cancer patients with genetic mutations in EGFR. The aim of this study was to investigate the existence of EGFR mutations in carcinoma of esophagogastric junction, and also to explore the possibility of treating carcinoma of esophagogastric junction using gefitinib.</p> <p>Methods</p> <p>From Aug. 2009 to Jun. 2010, 65 patients with carcinoma of esophagogastric junction underwent surgical resection. The tumor tissue and corresponding blood specimens were collected from all cases. The DNA was extracted and PCR amplification was accomplished based on designed primers for exons 18, 19, 20, and 21. EGFR exons 18, 19, 20 and 21 of both cancer cell and white blood cell were finally successfully sequenced.</p> <p>Results</p> <p>In exon 20, a variant from CAG to CAA at codon 787 (2361G-> A) was identified in 19 patients, which was a genomic variation of EGFR since it was found in both cancer tissue and white blood cells. This EGFR alteration was a synonymous single nucleotide polymorphism (SNP) since CAA and CAG were encoding the same amino-acid of Glutamine (Q787Q, NCBI database 162093G > A, SNP ID: rs10251977). No genetic alteration was found in exons 18, 19 or 21.</p> <p>Conclusions</p> <p>Adenocarcinoma of esophagogastric junction rarely presents EGFR mutation, especially gefitinib-associated mutations such as L858R, or delE746-A750. This means that the gefitinib-based gene target therapy should not be recommended for treating carcinoma of esophagogastric junction.</p

    Experimental realization of universal high-dimensional quantum gates with ultra-high fidelity and efficiency

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    Qudit, a high-dimensional quantum system, provides a larger Hilbert space to process the quantum information and has shown remarkable advantages over the qubit counterparts. It is a great challenge to realize the high fidelity universal quantum gates with qudits. Here we theoretically propose and experimentally demonstrate a set of universal quantum gates for a single optical qudit with four dimensions (including the generalized Pauli X4X_4 gate, Pauli Z4Z_4 gate, and all of their integer powers), which are encoded in the polarization-spatial degree of freedom without multiple unstable cascaded interferometers. Furthermore, we also realize the controlled-X4X_4 gate and all of its integer powers. We have achieved both the ultra-high average gate fidelity 99.73%99.73\% and efficiency 99.47%99.47\%, which are above the the error threshold for fault-tolerant quantum computation. Our work paves a way for the large-scale high-dimensional fault-tolerant quantum computation with a polynomial resource cost

    Fidelity susceptibility, scaling, and universality in quantum critical phenomena

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    We study fidelity susceptibility in one-dimensional asymmetric Hubbard model, and show that the fidelity susceptibility can be used to identify the universality class of the quantum phase transitions in this model. The critical exponents are found to be 0 and 2 for cases of half-filling and away from half-filling respectively.Comment: 4 pages, 4 figure

    Quantum criticality of the Lipkin-Meshkov-Glick Model in terms of fidelity susceptibility

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    We study the critical properties of the Lipkin-Meshkov-Glick Model in terms of the fidelity susceptibility. By using the Holstein-Primakoff transformation, we obtain explicitly the critical exponent of the fidelity susceptibility around the second-order quantum phase transition point. Our results provide a rare analytical case for the fidelity susceptibility in describing the universality class in quantum critical behavior. The different critical exponents in two phases are non-trivial results, indicating the fidelity susceptibility is not always extensive.Comment: 3 figure

    Preparation and properties of a washable flame-retardant coated fabric

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    In this study, a flame-retardant-coating (FRC) agent has been prepared using hydrophobic organic silicone-phosphorus-nitrogen flame retardant and acrylic emulsion. Polyester-cotton blend fabric (P/C) has been treated with FRC agent, and the finishing process, thermal decomposition, flame retardancy, washability, softness and other properties are studied. Results show that the treated fabrics are of good flame retardancy; LOI is up to 32%, thermal degradation rate reduces by 7.8 %/min and thermal damage reduces by 74%. Limiting oxygen index (LOI) is found to be 24.6% and 23.7% for 5 and 10 times washing. The fastness shows excellent washability

    A Novel Nomogram Model to Predict the Recurrence-Free Survival and Overall Survival of Hepatocellular Carcinoma

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    BackgroundTreatments for patients with early‐stage hepatocellular carcinoma (HCC) include liver transplantation (LT), liver resection (LR), radiofrequency ablation (RFA), and microwave ablation (MWA), are critical for their long-term survival. However, a computational model predicting treatment-independent prognosis of patients with HCC, such as overall survival (OS) and recurrence-free survival (RFS), is yet to be developed, to our best knowledge. The goal of this study is to identify prognostic factors associated with OS and RFS in patients with HCC and develop nomograms to predict them, respectively.MethodsWe retrospectively retrieved 730 patients with HCC from three hospitals in China and followed them up for 3 and 5 years after invasive treatment. All enrolled patients were randomly divided into the training cohort and the validation cohort with a 7:3 ratio, respectively. Independent prognostic factors associated with OS and RFS were determined by the multivariate Cox regression analysis. Two nomogram prognostic models were built and evaluated by concordance index (C-index), calibration curves, area under the receiver operating characteristics (ROC) curve, time-dependent area under the ROC curve (AUC), the Kaplan–Meier survival curve, and decision curve analyses (DCAs), respectively.ResultsPrognostic factors for OS and RFS were identified, and nomograms were successfully built. Calibration discrimination was good for both the OS and RFS nomogram prediction models (C-index: 0.750 and 0.746, respectively). For both nomograms, the AUC demonstrated outstanding predictive performance; the DCA shows that the model has good decision ability; and the calibration curve demonstrated strong predictive power. The nomograms successfully discriminated high-risk and low-risk patients with HCC associated with OS and RFS.ConclusionsWe developed nomogram survival prediction models to predict the prognosis of HCC after invasive treatment with acceptable accuracies in both training and independent testing cohorts. The models may have clinical values in guiding the selection of clinical treatment strategies
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