3,172 research outputs found

    Finite volume effects of the Nambu-Jona-Lasinio model with the running coupling constant

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    With the Schwinger's proper-time formalism of the Nambu-Jona-Lasinio model, we investigate the finite volume effects in the presence of magnetic fields. Since the coupling constant GG can be influenced by strong magnetic fields, the model is solved with a running coupling constant G(B)G(B) which is fitted by the lattice average (Σu+Σd)/2(\Sigma_u+\Sigma_d)/2 and difference ΣuΣd\Sigma_u-\Sigma_d. The investigation mainly focuses on the constituent quark mass and the thermal susceptibility depending on the magnetic fields, the temperatures and the finite sizes. For the model in finite or infinite volume, the magnetic fields can increase the constituent quark mass while the temperatures can decrease it inversely. There is a narrow range of the box length that makes the effects of finite volume perform prominently. The model will behave close to infinite volume limit for larger box length. It is shown that the influence of finite volume can be changed by magnetic fields and temperatures. Finally, we discuss the thermal susceptibility depending on the temperature in finite volume in the presence of magnetic fields.Comment: 13 pages, 6 figure

    Fault diagnosis and fault-tolerant control for system with fast time-varying delay

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    This paper proposes a fault diagnosis and fault-tolerant control method for a system with a fast time-varying delay and time-varying parameters. A fault observer is designed to estimate faults, and an improved fast adaptive fault estimation (FAFE) algorithm is developed to reduce the relevant constraints in the general form of this algorithm. With newly introduced relaxation matrices, this study estimates faults in a system exhibiting a fast time-varying delay. Based on the estimated faults, an output feedback controller is designed to accommodate the faults. The fault-tolerant control is realized using the introduced relaxation matrices. An algorithm is derived to solve for the observer and controller. Finally, the theory and method are validated using a real example of a helicopter system

    Knockdown of TIGAR by RNA interference induces apoptosis and autophagy in HepG2 hepatocellular carcinoma cells

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    AbstractApoptosis and autophagy are crucial mechanisms regulating cell death, and the relationship between apoptosis and autophagy in the liver has yet to be thoroughly explored. TIGAR (TP53-induced glycolysis and apoptosis regulator), which is a p53-inducible gene, functions in the suppression of ROS (reactive oxygen species) and protects U2OS cells from undergoing cell death. In this study, silencing TIGAR by RNAi (RNA interference) in HepG2 cells down-regulated both TIGAR mRNA (∼75%) and protein levels (∼80%) and led to the inhibition of cell growth (P<0.01) by apoptosis (P<0.001) and autophagy. We demonstrated that TIGAR can increase ROS levels in HepG2 cells. The down-regulation of TIGAR led to the induction of LC-3 II (specific autophagic marker), the formation of the autophagosome, and increased Beclin-1 expression. 3-MA (3-Methyladenine), an inhibitor of autophagic sequestration blocker, inhibited TIGAR siRNA-enhanced autophagy, as indicated by the decrease in LC-3 II levels. Consequently, these data provide the first evidence that targeted silencing of TIGAR induces apoptotic and autophagic cell death in HepG2 cells, and our data raise hope for the future successful application of TIGAR siRNA in patients with hepatocellular carcinoma (HCC)

    Surgical techniques for early-stage thymoma: Video-assisted thoracoscopic thymectomy versus transsternal thymectomy

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    ObjectiveThe present study compared the outcomes between patients who had undergone video-assisted thoracoscopic surgery (VATS) thymectomy and transsternal (TS) thymectomy for Masaoka stage I and II thymoma.MethodsThe outcomes of 262 patients without myasthenia gravis who had undergone surgery for Masaoka stage I and II thymoma from January 2008 to December 2012 at our center were retrospectively evaluated. The study included 125 patients who had undergone unilateral VATS thymectomy (VATS group) and 137 patients who had undergone TS thymectomy (TS group).ResultsThe VATS group had a shorter operative time than the TS group (170 vs 210 minutes, P < .001). The VATS group also had a smaller intraoperative blood loss (200 vs 450 mL, P < .001), smaller pleural drainage volume in the first 24 hours postoperatively (300 vs 500 mL, P < .0010), shorter postoperative pleural drainage duration (3 vs 5 days, P < .001), and shorter postoperative hospital stay (8 vs 10 days, P < .001). Four patients in the VATS group underwent conversion to open surgery because of injury to the innominate vein. The postoperative complication rate was similar between the 2 groups. One patient in the VATS group developed pleural recurrence, and one in the TS group developed local recurrence.ConclusionsUnilateral VATS thymectomy for Masaoka stage I and II thymoma is technically feasible and safe and is less invasive than TS thymectomy, with a shorter duration of surgery, less intraoperative blood loss, less postoperative pleural drainage, shorter postoperative pleural drainage duration, and shorter postoperative hospital stay. We have concluded that it is preferable to perform VATS thymectomy, although perhaps under certain circumstances sternotomy might be preferred. The oncologic outcomes were comparable between the 2 procedures. Additional follow-up is required to evaluate the long-term outcomes

    Antisense inhibition of ATM gene enhances the radiosensitivity of head and neck squamous cell carcinoma in mice

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    <p>Abstract</p> <p>Background</p> <p>Treatment failure after radiotherapy of head and neck squamous cell carcinoma (HNSCC) could be a significant problem. Our objective is to sensitize SCCVII cells to ionizing radiation <it>in vitro </it>and <it>in vivo </it>through inhibiting ATM expression using antisense oligodeoxynucleotides (AS-ODNs), and investigate the potential mechanism of radiosensitization.</p> <p>Methods</p> <p>We designed and synthesized AS-ODNs that target ATM mRNA to reduce the ATM expression. The influence on the expression of ATM mRNA and protein in SCCVII cells were analysed by real-time quantitative PCR and western blotting respectively. Clonogenic survival assay was performed to detect the survival ability of SCCVII cells after irradiation, while flow cytometry used to analyse the cell cycle and apoptosis. The volume of solid tumors generated with SCCVII cells was measured, and cell apoptosis was analysed by TUNEL assay after irradiation.</p> <p>Results</p> <p>The relative ATM mRNA and protein expression in SCCVII cells treated with ATM AS-ODNs were decreased to 25.7 ± 3.1% and 24.1 ± 2.8% of that in untreated cells respectively (<it>P </it>< 0.05). After irradiation, the survival fraction (SF) of cells treated with ATM AS-ODNs was lower than that of other groups at the same dose of radiation (<it>P </it>< 0.05), while the percentage of cells in G2/M phase decreased and apoptotic rate of cells increased(<it>P </it>< 0.05). The inhibition rate in SCCVII cells solid tumor exposed to X-ray alone was 23.2 ± 2.7%, while it was 56.1 ± 3.8% in the group which irradiated in combination with the treatment of ATM AS-ODNs (<it>P </it>< 0.05). The apoptotic index for the group irradiated in combination with ATM AS-ODNs injection was 19.6 ± 3.2, which was significantly higher than that of others (<it>P </it>< 0.05)</p> <p>Conclusion</p> <p>Inhibition of ATM expression sensitized SCCVII cells to ionizing radiation <it>in vitro </it>and <it>in vivo</it>. The potential mechanism should be the defective G2/M cell cycle checkpoint control and enhanced radiation-induced apoptosis.</p

    eIF3a: A new anticancer drug target in the eIF family

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    eIF3a is the largest subunit of eIF3, which is a key player in all steps of translation initiation. During the past years, eIF3a is recognized as a proto-oncogene, which is an important discovery in this field. It is widely reported to be correlated with cancer occurrence, metastasis, prognosis, and therapeutic response. Recently, the mechanisms of eIF3a action in the carcinogenesis are unveiled gradually. A number of cellular, physiological, and pathological processes involving eIF3a are identified. Most importantly, it is emerging as a new potential drug target in the eIF family, and some small molecule inhibitors are being developed. Thus, we perform a critical review of recent advances in understanding eIF3a physiological and pathological functions, with specific focus on its role in cancer and anticancer drug targets

    3-Bromo-4-dibenzyl­amino-5-methoxy­furan-2(5H)-one

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    In the the title compound, C19H18BrNO3, the furan­one ring is almost planar [maximum atomic deviation = 0.019 (3) Å] and is nearly perpendicular to the two phenyl rings, making dihedral angles of 88.96 (17) and 87.71 (17)°. Inter­molecular C—H⋯O hydrogen bonding is present in the crystal structure
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