2,580 research outputs found

    Structure-activity relationships of synthetic analogs of jasmonic acid and coronatine on induction of benzo[c]phenanthridine alkaloid accumulation in Eschscholzia californica cell cultures

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    A facile test system based on the accumulation of benzo[c]phenanthridine alkaloids in Eschscholzia californica cell suspension culture (an indicator of defense gene activation) has been used to analyze a series of synthetic compounds for elicitor-like activity. Of the 200 jasmonic acid and coronatine analogs tested with this system, representative results obtained with 49 of them are presented here. The following can be summarized concerning structure-actvity relationships: there is a large degree of plasticity allowed at the C-3 of jasmonic acid in the activation of defense genes. The carbonyl moiety is not strictly required, but exocyclic double bond character appears necessary. The pentenyl side chain at C-2 cannot tolerate bulky groups at the terminal carbon and still be biologically active. Substitutions to the C-1' position are tolerated if they can potentially undergo beta-oxidation. Either an alkanoic acid or methyl ester is required at c-l, or a side chain that can be shortened by beta-oxidation or by peptidase hydrolysis. Coronatine and various derivatives thereof are not as effective as jasmonic acid, and derivatives in inducing benzo[c]phenanthridine alkaloid accumulation. Jasmonic acid rather than the octadecanoic precursors is therefore considered to be a likely signal transducer of defense gene activation in planta

    Hyperbolic Kac-Moody superalgebras

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    We present a classification of the hyperbolic Kac-Moody (HKM) superalgebras. The HKM superalgebras of rank larger or equal than 3 are finite in number (213) and limited in rank (6). The Dynkin-Kac diagrams and the corresponding simple root systems are determined. We also discuss a class of singular sub(super)algebras obtained by a folding procedure

    Water vapor radiometry research and development phase

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    This report describes the research and development phase for eight dual-channel water vapor radiometers constructed for the Crustal Dynamics Project at the Goddard Space Flight Center, Greenbelt, Maryland, and for the NASA Deep Space Network. These instruments were developed to demonstrate that the variable path delay imposed on microwave radio transmissions by atmospheric water vapor can be calibrated, particularly as this phenomenon affects very long baseline interferometry measurement systems. Water vapor radiometry technology can also be used in systems that involve moist air meteorology and propagation studies

    Pressure-induced phase transition and bi-polaronic sliding in a hole-doped Cu_2O_3 ladder system

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    We study a hole-doped two-leg ladder system including metal ions, oxygen, and electron-lattice interaction, as a model for Sr_{14-x}Ca_xCu_{24}O_{41-\delta}. Single- and bi-polaronic states at 1/4-hole doping are modeled as functions of pressure by applying an unrestricted Hartree-Fock approximation to a multiband Peierls-Hubbard Hamiltonian. We find evidence for a pressure-induced phase transition between single-polaron and bi-polaron states. The electronic and phononic excitations in those states, including distinctive local lattice vibrational modes, are calculated by means of a direct-space Random Phase approximation. Finally, as a function of pressure, we identify a transition between site- and bond-centered bi-polarons, accompanied by a soft mode and a low-energy charge-sliding mode. We suggest comparisons with available experimented data

    The table mountain 8-mm-wavelength interferometer

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    The system components, performance, and calibration of two element radio interferometer operating at 8.33 mm wavelength are discussed. The interferometer employs a 5.5 m and a 3 m diameter antenna on an east-west baseline of 60 or 120 m, yielding fringe spacings at transit of 28 or 14 in. respectively. The broad intermediate frequency bandpass of 100 to 350 MHz and the system noise temperature of 500 K provide high sensitivity for the measurement of continuum sources. The interferometer has been used for high resolution studies of the planets and the Sun, and it is currently being adapted to study solar flare emissions at high spatial and time resolution

    Anyonic Realization of the Quantum Affine Lie Superalgebra U_q(A(M,N)^{(1)})

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    We give a realization of the quantum affine Lie superalgebras U_q(A(M,N))^(1) in terms of anyons defined on a one or two-dimensional lattice, the deformation parameter q being related to the statistical parameter ν\nu of the anyons by q = exp(i\pi\nu). The construction uses anyons contructed from usual fermionic oscillators and deformed bosonic oscillators. As a byproduct, realization deformed in any sector of the quantum superalgebras U_q(A(M,N)) is obtained.Comment: 14p LaTeX Document (should be run twice

    "Avaliação da higienização do resíduo de caixa de areia de estações de tratamento de esgoto"

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    O processo de tratamento de esgoto doméstico gera resíduos sólidos que precisam ser constantemente removidos afim de se manter a eficiência do tratamento, dentre eles, o resíduo depositado no fundo das caixas de areia. A caixa de areia tem como objetivo remover do esgoto areia e outras partículas, incluindo as orgânicas, presentes no esgoto in natura, que através do processo de sedimentação são arrastadas para o fundo. Apesar de não receber a devida importância, uma vez que a prática é enterrar este resíduo em valas ou dispor no solo sem tratamento, atualmente, este resíduo passou a ser considerado um problema no gerenciamento de estações no que se refere ao manuseio, tratamento e destinação final, devido a exigências por parte das empresas de saneamento. Visto a necessidade de buscar novas fontes de obtenção de areia, o resíduo de caixa de areia poderia ser uma opção a ser utilizada na construção civil desde que seja realizada a higienização prévia do material. O objetivo deste trabalho foi avaliar a eficiência da caleagem e da insolação natural na higienização do resíduo de caixa de areia através da avaliação da redução de bactérias do grupo coliforme e de ovos de helmintos. A metodologia adotada neste trabalho possui 2 etapas. Na primeira etapa, Estudos Preliminares, buscou-se conhecer as características físicas e microbiológicas da areia, desenvolver procedimentos de coleta e montagem dos experimentos e testar processos de higienização através da caleagem, cloração e insolação natural. Na segunda etapa, Estudo Piloto, avaliou-se a eficiência da caleagem na higienização através da repetição de experimentos. Os resultados obtidos permitiram constatar a eficiência da caleagem na higienização do resíduo de caixa de areia a partir da dosagem de 10% pode ser considerada eficiente na remoção de bactérias e ovos de helmintos após uma semana de tratamento e a dosagem a partir de 15% eficiente após 48 horas de tratamento e as análises preliminares visando utilizar a areia higienizada demonstram ser viável sua aplicação na construção civil sob o ponto de vista sanitário, e garantem a segurança do manuseio, transporte e destinação final

    Uq[sl(2∣1)^]U_q[\hat{sl(2|1)}] Vertex Operators, Screen Currents and Correlation Functions at Arbitrary Level

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    Bosonized q-vertex operators related to the 4-dimensional evaluation modules of the quantum affine superalgebra Uq[sl(2∣1)^]U_q[\hat{sl(2|1)}] are constructed for arbitrary level k=αk=\alpha, where α≠0,−1\alpha\neq 0, -1 is a complex parameter appearing in the 4-dimensional evaluation representations. They are intertwiners among the level-α\alpha highest weight Fock-Wakimoto modules. Screen currents which commute with the action of Uq[sl(2∣1)^]U_q[\hat{sl(2|1)}] up to total differences are presented. Integral formulae for N-point functions of type I and type II q-vertex operators are proposed.Comment: Latex file 18 page

    Vascular hyperpermeability in severe influenza

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    Multiorgan failure with vascular hyperpermeability is the final outcome in the progression of seasonal influenza virus pneumonia and influenza-associated encephalopathy, and it is also common in infection with highly pathogenic avian influenza virus. However, the precise molecular mechanism by which influenza virus infection causes vascular endothelial cell hyperpermeability remains poorly defined. We investigated the mechanisms of hyperpermeability of human umbilical vein endothelial cells infected with influenza A virus (IAV)/Puerto Rico/8/34 (PR8) (H1N1). The levels of β-catenin, a key regulatory component of the vascular endothelial-cadherin cell adhesion complex, were markedly decreased during infection for 28 h, with increments of vascular hyperpermeability measured by transendothelial electrical resistance. Lactacystin (at 2 μM), a proteasome inhibitor, inhibited the decrease in β-catenin levels. Since the N-terminal phosphorylation of β-catenin by glycogen synthase kinase (GSK)-3β is the initiation step of proteasome-dependent degradation, we examined the effects of GSK-3β suppression by RNA interference in endothelial cells. IAV-infection-induced β-catenin degradation was significantly inhibited in GSK-3β-knockdown cells, and transfection of cells with recombinant β-catenin significantly suppressed IAV-induced hyperpermeability. These findings suggest that IAV infection induces GSK-3β-mediated β-catenin degradation in the adherens junctional complexes and induces vascular hyperpermeability. The in vitro findings of β-catenin degradation and activation of GSK-3β after IAV infection were confirmed in lungs of mice infected with IAV PR8 during the course of infection from day 0 to day 6. These results suggest that GSK-3β-mediated β-catenin degradation in adherens junctions is one of the key mechanisms of vascular hyperpermeability in severe influenza

    Transfer matrix eigenvalues of the anisotropic multiparametric U model

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    A multiparametric extension of the anisotropic U model is discussed which maintains integrability. The R-matrix solving the Yang-Baxter equation is obtained through a twisting construction applied to the underlying Uq(sl(2|1)) superalgebraic structure which introduces the additional free parameters that arise in the model. Three forms of Bethe ansatz solution for the transfer matrix eigenvalues are given which we show to be equivalent.Comment: 26 pages, no figures, LaTe
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