3 resultados para Nondegenerate Parametric Amplification

em DI-fusion - The institutional repository of Université Libre de Bruxelles


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Overexpression and amplification of the HER-2 oncogene in patients with breast cancer has correlated with early onset of metastasis, resistance to hormonal therapy and some forms of chemotherapy, and shortened survival. Therefore, evaluation of this putative prognostic or predictive factor seems critical. Because different antibodies are used for the detection of the 185-kd HER-2 oncoprotein, we studied the sensitivity of 3 frequently used antibodies. Immunohistochemistry results were correlated with gene amplification level as assessed by fluorescence in situ hybridization. Protein overexpression was found in 17.2% and 12.5% of cases using antibodies against the external (TAB250) and internal (CB11) domains of the protein, respectively, and in 38.0% of cases using a rabbit polyclonal antibody. Fluorescence in situ hybridization was successful in all 160 tumors, and amplification was found in 37 tumors (23.1%). The monoclonal antibody TAB250 had the lowest misclassification rate, 9.6% (sensitivity, 67%; specificity, 97.5%).

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Plastid microsatellite loci developed for Cephalanthera longifolia were used to examine the level of genetic variation within and between populations of the three widespread Cephalanthera species (C. damasonium, C. longifolia and C. rubra). The most detailed sampling was in C. longifolia (42 localities from Ireland to China; 147 individuals). Eight haplotypes were detected. One was detected in the vast majority of individuals and occurred from Ireland to Iran. Three others were only found in Europe (Ireland to Italy, England to Italy and Austria to Croatia). Two were only found in the Middle East and two only in Asia. In C. damasonium, 21 individuals from 10 populations (England to Turkey) were sampled. Only one haplotype was detected. In C. rubra, 34 individuals from eight populations (England to Turkey) were sampled. Although it was not possible to amplify all loci for all samples of this species, nine haplotypes were detected. Short alleles for the trnS-trnG region found in two populations of C. rubra were characterized by sequencing and were caused by deletions of 26 and 30 base pairs. At this level of sampling, it appears that C. rubra shows the greatest genetic variability. Cephalanthera longifolia, C. rubra and C. damasonium have previously been characterized as outbreeding, outbreeding with facultative vegetative reproduction and inbreeding, respectively. Patterns of genetic variation here are discussed in the light of these reproductive system differences. The primers used in these three species of Cephalanthera were also demonstrated to amplify these loci in another five species (C. austiniae, C. calcarata, C. epipactoides, C. falcata and C. yunnanensis). Although it is sometimes treated as a synonym of C. damasonium, the single sample of C. yunnanensis from China had a markedly different haplotype from that found in C. damasonium. All three loci were successfully amplified in two achlorophyllous, myco-heterotrophic species, C. austinae and C. calcarata. © 2010 The Linnean Society of London.

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Supercontinuum generation is investigated experimentally and numerically in a highly nonlinear indexguiding photonic crystal optical fiber in a regime in which self-phase modulation of the pump wave makes a negligible contribution to spectral broadening. An ultrabroadband octave-spanning white-light continuum is generated with 60-ps pump pulses of subkilowatt peak power. The primary mechanism of spectral broadening is identified as the combined action of stimulated Raman scattering and parametric four-wave mixing. The observation of a strong anti-Stokes Raman component reveals the importance of the coupling between stimulated Raman scattering and parametric four-wave mixing in highly nonlinear photonic crystal fibers and also indicates that non-phase-matched processes contribute to the continuum. Additionally, the pump input polarization affects the generated continuum through the influence of polarization modulational instability. The experimental results are in good agreement with detailed numerical simulations. These findings demonstrate the importance of index-guiding photonic crystal fibers for the design of picosecond and nanosecond supercontinuum light sources. © 2002 Optical Society of America.