265 research outputs found

    Guided Modes in the Plane Array of Optical Waveguides

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    It is known that for an isolated dielectric cylinder waveguide there exists the cutoff frequency ω\omega_\ast below which there is no guided mode. It is shown in the paper that the infinite plane periodic array of such waveguides possesses the guided modes in the frequency domain which is below the frequency ω\omega_\ast. In the case of a finite array, the modes in this frequency domain are weakly radiating ones, but their quality factor QQ increases with the number of waveguides NN as Q(N)N3Q(N)\sim N^3. This dependence is obtained both numerically, using the multiple scattering formalism, and is justified with a simple analytical model

    Bis(dihydrogen norfloxacinium) tri-μ2-chlorido-bis­[trichloridobismuthate(III)] chloride dihydrate

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    The title compound, {systematic name: (3-carb­oxy-1-ethyl-6-fluoro-7-piperazin-4-ium-1-yl-1H-quinolin-4-yl­idene)oxonium tri-μ2-chlorido-bis­[trichloridobismuthate(III)] chloride dihydrate], (C16H20FN3O3)2[Bi2Cl9]Cl·2H2O, is composed of [Bi2Cl9]3− anions lying on crystallographic twofold rotation axes, Cl− anions also on twofold axes, C16H20FN3O3 2+ cations, and water mol­ecules. The BiIII coordination polyhedron is a distorted octa­hedron and two such octa­hedra share a triangular face to form the complex anion. There are three short terminal Bi—Cl bonds [2.5471 (6)–2.5781(5 Å] and three longer bridging bonds [2.8599 (5)–2.9984 (6) Å] in each octa­hedron. Anions, cations and water mol­ecules are linked by hydrogen bonds to form a three-dimensional network. There are also π–π stacking inter­actions between quinoline ring systems, with an inter­planar distance of 3.27 (1) Å

    Connexin-Mediated Signaling in Nonsensory Cells Is Crucial for the Development of Sensory Inner Hair Cells in the Mouse Cochlea

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    Mutations in the genes encoding for gap junction proteins connexin 26 (Cx26) and connexin 30 (Cx30) have been linked to syndromic and nonsyndromic hearing loss in mice and humans. The release of ATP from connexin hemichannels in cochlear nonsensory cells has been proposed to be the main trigger for action potential activity in immature sensory inner hair cells (IHCs), which is crucial for the refinement of the developing auditory circuitry. Using connexin knock-out mice, we show that IHCs fire spontaneous action potentials even in the absence of ATP-dependent intercellular Ca(2+) signaling in the nonsensory cells. However, this signaling from nonsensory cells was able to increase the intrinsic IHC firing frequency. We also found that connexin expression is key to IHC functional maturation. In Cx26 conditional knock-out mice (Cx26(Sox10-Cre)), the maturation of IHCs, which normally occurs at approximately postnatal day 12, was partially prevented. Although Cx30 has been shown not to be required for hearing in young adult mice, IHCs from Cx30 knock-out mice exhibited a comprehensive brake in their development, such that their basolateral membrane currents and synaptic machinery retain a prehearing phenotype. We propose that IHC functional differentiation into mature sensory receptors is initiated in the prehearing cochlea provided that the expression of either connexin reaches a threshold level. As such, connexins regulate one of the most crucial functional refinements in the mammalian cochlea, the disruption of which contributes to the deafness phenotype observed in mice and DFNB1 patients. SIGNIFICANCE STATEMENT: The correct development and function of the mammalian cochlea relies not only on the sensory hair cells, but also on the surrounding nonsensory cells. Although the nonsensory cells have been largely implicated in the general homeostasis in the mature cochlea, their involvement in the initial functional differentiation of the sensory inner hair cells is less clear. Using mutant mouse models for the most common form of congenital deafness in humans, which are knock-outs for the gap-junction channels connexin 26 and connexin 30 genes, we show that defects in nonsensory cells prevented the functional maturation of inner hair cells. In connexin knock-outs, inner hair cells remained stuck at a prehearing stage of development and, as such, are unable to process sound information

    Study of the functional product’s protein compounds digestion features

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    The aim of the study was to investigate the transformation of meat product’s proteins from pig hearts and aortas during enzymatic hydrolysis in an in vitro model of the gastrointestinal tract. The model consisted of three phases simulating digestion processes: “oral cavity” phase (a-amylase, pH 7.0; 2 min), “stomach” phase (pork pepsin, pH 3.0; 120 min), “intestine” phase (pork pancreatin, pH 7.0; 130 min). The product was sequentially subjected to hydrolysis, at the end of each phase, samples were taken to determine the protein concentration (biuret method) and visualize the protein fractions (one-dimensional electrophoresis). A significant increase in protein concentration at the “stomach” phase was revealed by 3.2 times, and the absolute content by 4.6 times. At the “intestine” phase, a decrease in the number of peptide complexes with copper ions by 1.8 times, the absolute protein content by 8.5% was re‑ vealed. The noted tendency was confirmed by electrophoretic studies — at the stage, simulating digestion in the stomach, the prod‑ ucts of meat product’s proteins hydrolysis were visualized; at the “intestine” phase, a low expression of protein fractions in the range of more than 10 kDa is shown. The maximum hydrolysis of protein compounds at the “stomach” phase to poly- and oligopeptides was confirmed, continuing at the “intestine” stage with the accumulation of free amino acids. This methodology makes it possible to visualize the products of hydrolysis of proteins in a meat product at all stages of the model and to monitor changes in protein concentration in the system

    Cohomology Groups of Deformations of Line Bundles on Complex Tori

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    The cohomology groups of line bundles over complex tori (or abelian varieties) are classically studied invariants of these spaces. In this article, we compute the cohomology groups of line bundles over various holomorphic, non-commutative deformations of complex tori. Our analysis interpolates between two extreme cases. The first case is a calculation of the space of (cohomological) theta functions for line bundles over constant, commutative deformations. The second case is a calculation of the cohomologies of non-commutative deformations of degree-zero line bundles.Comment: 24 pages, exposition improved, typos fixe
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