242 research outputs found

    Period doubling eigenstates in a fiber laser mode-locked by nonlinear polarization rotation

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    Due to the weak birefringence of single mode fibers, solitons generated in fiber lasers are indeed vector pulses and exhibit periodic parameter change including polarization evolution even when there is a polarizer inside the cavity. Period doubling eigenstates of solitons generated in a fiber laser mode-locked by the nonlinear polarization rotation, i.e., period doubling of polarization components of the soliton, are numerically explored in detail. We found that, apart from the synchronous evolution between the two polarization components, there exists asynchronous development depending on the detailed operation conditions. In addition, period doubling of one polarization component together with period-one of another polarization component can be achieved. When the period tripling window is obtained, much complexed dynamics on the two polarization components could be observed.Comment: 6 page

    IL-6 production in ovarian carcinoma is associated with histiotype and biological characteristics of the tumour and influences local immunity

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    The presence of interleukin (IL)-6 in peritoneal carcinomatous fluid (PCF) and its effect on immune cells composition in PCF in patients with advanced ovarian carcinoma was studied. In 21 out of 30 ovarian carcinoma patients, PCF IL-6 levels were found to exceed those seen in PCFs of patients with gastrointestinal cancer. IL-6 activity was higher in serous/mucinous than in endometrioid and undifferentiated ovarian carcinoma PCF (P = 0.05). Ovarian carcinoma PCF IL-6 activities were correlated with serum C-reactive protein levels (r = 0.65, P = 0.0000, n = 25). Ovarian carcinoma PCF leucocyte profile differed from that in blood with respect to: (i) lower percentage of NK and CD8+and (ii) higher percentage of B and CD45RO+, CD14+and HLA-DR+cells. The proportions of CD45RO+in blood were correlated with IL-6 levels in PCF. Corresponding to PCF ovarian carcinoma tumours were stained for the presence of Ki-67 antigen and p53. The highest proportions of Ki-67+cells and cells showing accumulation of p53 were seen in undifferentiated tumours. A low grade of p53 staining was seen in tumours associated with high IL-6 levels in PCF. It was evident that IL-6 production (i) depended on the histiotype of the tumour, (ii) influenced the local immune system in favour of accumulation of B, and T memory cells, and (iii) was higher in patients lacking p53 accumulation. © 2000 CancerResearch Campaig

    Nonlinear Absorbing-Loop Mirror in a Holmium-Doped Fiber Laser

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    Period doubling of multiple dissipative-soliton-resonance pulses in a fibre laser

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    We report on the experimental observation of the period doubling of multiple dissipative-soliton-resonance (DSR) pulses in an all-normal-dispersion fibre laser, based on a nonlinear amplifying loop mirror. By increasing the pump power, the transition from a single DSR pulse to multiple DSR pulses was observed, in addition to the typical linear pulse broadening, under a fixed pulse peak power. During this process, period doubling appeared because the DSR pulses can exhibit the characteristics of period doubling in a multi-pulse state. The typical DSR performance of a linear pulse duration change, versus the variation of pump power, can be maintained when the period doubling of multiple DSR pulses appears

    Breach and recurrence of dissipative soliton resonance during period-doubling evolution in a fiber laser

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    We report on the experimental observation of period-doubling bifurcation of dissipative-soliton-resonance (DSR) pulses in a fiber laser passively mode-locked by using the nonlinear optical loop mirror. Increasing the pump power of the fiber laser, we show that temporally a stable, uniform DSR pulse train could be transformed into a period-doubling state, exhibiting two sets of pulse parameters between the adjacent cavity roundtrip. It is found that DSR pulses in the period-doubling state could maintain the typical feature of DSR pulse: fixed pulse peak power and linear variation in pulse width with respect to the pump power change. The mechanism for achieving period-doubling of DSR pulses is discussed.Comment: 9 page

    A conserved phosphorylation site regulates the transcriptional function of ETHYLENE-INSENSITIVE3-like1 in tomato

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    ETHYLENE-INSENSITIVE3/ETHYLENE-INSENSITIVE3-like (EIN3/EIL) transcription factors are important downstream components of the ethylene transduction pathway known to regulate the transcription of early ethylene-responsive genes in plants. Previous studies have shown that phosphorylation can repress their transcriptional activity by promoting protein degradation. The present study identifies a new phosphorylation region named EPR1 (EIN3/EIL phosphorylation region 1) in tomato EIL1 proteins. The functional significance of EPR1 was tested by introducing mutations in this region of the Sl-EIL1 gene and by expressing these mutated versions in transgenic tomato plants. Transient expression data and phenotypic analysis of the transgenic lines indicated that EPR1 is essential for the transcriptional activity of Sl-EIL1. Moreover, mutation in the EPR1 site that prevents phosphorylation abolishes ethylene constitutive responses normally displayed by the Sl-EIL1-overexpressing lines. Bimolecular fluorescence complementation (BiFC) studies showed that the presence of a functional phosphorylation site within EPR1 is instrumental in the dimerization of Sl-EIL1 proteins. The results illuminate a new molecular mechanism for the control of EIN3/EIL activity and propose a model where phosphorylation within the EPR1 promotes the dimerization process allowing the initiation of EIL-mediated transcription of early ethylene-regulated genes
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