11 research outputs found

    Generation of slow intense optical solitons in a resonance photonic crystal

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    We demonstrate interesting and previously unforeseen properties of a pair of gap solitons in a resonant photonic crystal which are predicted and explained in a physically transparent form using both analytical and numerical methods. The most important result is the fact that an oscillating gap soliton created by the presence of a localized population inversion inside the crystal can be manipulated by means of a proper choice of bit rate, phase and amplitude modulation. Developing this idea, we are able to obtain qualitatively different regimes of a resonant photonic crystal operation. In particular, a noteworthy observation is that both the delay time and amplitude difference must exceed a certain level to ensure effective control over the soliton dynamics

    Impurity effects on optical response in a finite band electronic system coupled to phonons

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    The concepts, which have traditionally been useful in understanding the effects of the electron--phonon interaction in optical spectroscopy, are based on insights obtained within the infinite electronic band approximation and no longer apply in finite band metals. Impurity and phonon contributions to electron scattering are not additive and the apparent strength of the coupling to the phonon degrees of freedom is substantially reduced with increased elastic scattering. The optical mass renormalization changes sign with increasing frequency and the optical scattering rate never reaches its high frequency quasiparticle value which itself is also reduced below its infinite band value

    The puzzle of 90 degree reorientation in the vortex lattice of borocarbide superconductors

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    We explain 90 degree reorientation in the vortex lattice of borocarbide superconductors on the basis of a phenomenological extension of the nonlocal London model that takes full account of the symmetry of the system. We propose microscopic mechanisms that could generate the correction terms and point out the important role of the superconducting gap anisotropy.Comment: 4 pages, 2 eps figure

    Anisotropic Peak Effect due to Structural Phase Transition in the Vortex Lattice

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    Experimental Evaluation of Food-Grade Semi-Refined Carrageenan Toxicity

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    The safety of food additives E407 and E407a has raised concerns in the scientific community. Thus, this study aims to assess the local and systemic toxic effects of the common food additive E407a in rats orally exposed to it for two weeks. Complex evaluations of the effects of semi-refined carrageenan (E407a) on rats upon oral exposure were performed. Local effects of E407a on the intestine were analyzed using routine histological stains and CD68 immunostaining. Furthermore, circulating levels of inflammatory markers were assessed. A fluorescent probe O1O (2- (2′-OH-phenyl)-5-phenyl-1,3-oxazole) was used for evaluating the state of leukocyte cell membranes. Cell death modes of leukocytes were analyzed by flow cytometry using Annexin V and 7-aminoactinomycin D staining. Oral administration of the common food additive E407a was found to be associated with altered small and large intestinal morphology, infiltration of the lamina propria in the small intestine with macrophages (CD68+ cells), high systemic levels of inflammation markers, and changes in the lipid order of the phospholipid bilayer in the cell membranes of leukocytes, alongside the activation of their apoptosis. Our findings suggest that oral exposure to E407a through rats results in the development of intestinal inflammation.</jats:p
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