2,221 research outputs found

    Mosca de las riberas (Diptera: Ephydridae) asociadas a plantines de lechuga en invernaderos

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    Mosca de las riberas (Diptera: Ephydridae) asociadas a plantines de lechuga en invernaderosFil: Lietti, Marcela. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias; Argentin

    Structural and functional characteristics and properties of metzincins

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    In this review the main families of endopeptidases belonging to the clan of metzincins of zinc-dependent metal-loproteinases in organisms of wide evolutional range from bacteria to mammals are considered. The data on classification, physicochemical properties, substrate specificity, and structural features of this group of enzymes are given. The activation mechanisms of metzincins, the role of these proteins in organisms, and their participation in various physiological processes are discussed. © 2012 Pleiades Publishing, Ltd

    Synthesis and characterization of carboxymethylcellulose grafted with thermoresponsive side chains of high LCST: The high temperature and high salinity self-assembly dependence

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    International audienceGraft copolymers based on carboxymethylcellulose (CMC) and thermosensitive polyetheramines (ethylene oxide/propylene oxide = 33/10 and 1/9) were prepared in water, at room temperature, by using a carbodiimide and N-hydroxysuccinimide as activators. SLS was applied to obtain M w , A 2 and R g of CMC and its derivatives. Amide linkages were evidenced by FTIR and grafting percentage was determined by 1 H NMR. TGA demonstrated that copolymers were thermally more stable than their precursors. DLS, UV-vis and rheological measurements revealed that properties were salt-and thermo-responsive and linked to the polysaccharide/polyetheramine ratio and the hydrophobicity of the graft. None of the copolymers showed cloud point temperature (Tcp) in water, but they turned turbid in saline media when heated. Copolymers exhibited thermothickening behaviour at 60°

    On Automated Lemma Generation for Separation Logic with Inductive Definitions

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    Separation Logic with inductive definitions is a well-known approach for deductive verification of programs that manipulate dynamic data structures. Deciding verification conditions in this context is usually based on user-provided lemmas relating the inductive definitions. We propose a novel approach for generating these lemmas automatically which is based on simple syntactic criteria and deterministic strategies for applying them. Our approach focuses on iterative programs, although it can be applied to recursive programs as well, and specifications that describe not only the shape of the data structures, but also their content or their size. Empirically, we find that our approach is powerful enough to deal with sophisticated benchmarks, e.g., iterative procedures for searching, inserting, or deleting elements in sorted lists, binary search tress, red-black trees, and AVL trees, in a very efficient way

    Strong, Ultra-narrow Peaks of Longitudinal and Hall Resistances in the Regime of Breakdown of the Quantum Hall Effect

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    With unusually slow and high-resolution sweeps of magnetic field, strong, ultra-narrow (width down to 100μT100 {\rm \mu T}) resistance peaks are observed in the regime of breakdown of the quantum Hall effect. The peaks are dependent on the directions and even the history of magnetic field sweeps, indicating the involvement of a very slow physical process. Such a process and the sharp peaks are, however, not predicted by existing theories. We also find a clear connection between the resistance peaks and nuclear spin polarization.Comment: 5 pages with 3 figures. To appear in PR

    Localization of alkaline phosphatase in bacillus intermedium Cells

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    Alkaline phosphatase, an enzyme secreted by Bacillus intermedius S3-19 cells to the medium, was also detected in the cell wall, membrane, and cytoplasm. The relative content of alkaline phosphatase in these cell compartments depended on the culture age and cultivation medium. The vegetative growth of B. intermedius on 0.3% lactate was characterized by increased activity of extracellular and membrane-bound phosphatases. The increase in lactate concentration to 3% did not affect the activity of membrane-bound phosphatase but led to a decrease in the activity of the extracellular enzyme. Na2UPO4 at a concentration of 0.01% diminished the activity of membrane-bound and extracellular phosphatases. CoCl2 at a concentration of 0.1 mM released membrane-bound phosphatase into the medium. By the onset of sporulation, phosphatase was predominantly localized in the medium and in the cell wall. As is evident from zymograms, the multiple molecular, forms of phosphatase varied depending on its cellular localization and growth phase

    The influence of carbon sources and mononucleotides on the production of extracellular alkaline phosphatase by bacillus intermedium

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    The biosynthesis of extracellular alkaline phosphatase in the streptomycin-resistant strains Bacillus intermedius S3-19 and S7 in the presence in the medium of 5′-nucleoside monophosphates and different sources of carbon-glucose, sodium pyruvate, sodium lactate, or glycerol-was studied. It was established that, in the presence of mononucleotides, the content of extracellular alkaline phosphatase in both strains increased; the maximal effect was caused by 5′-AMP at a concentration of 20 jig/ml. In medium with a low orthophosphate content, where active biosynthesis of alkaline phosphatase occurred, 1 % glucose and 0.5% pyruvate stimulated this process 2.5-4 times, and 2% sodium lactate and sodium pyruvate, on the contrary, inhibited it by 20-40%. Analysis of the dynamics of growth and accumulation of extracellular phosphatase in the presence of different sources of carbon in the medium gives evidence of an interrelationship between the biosynthesis of alkaline phosphatase and carbon metabolism in Bacillus intermedius

    Absence of Scaling in the Integer Quantum Hall Effect

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    We have studied the conductivity peak in the transition region between the two lowest integer Quantum Hall states using transmission measurements of edge magnetoplasmons. The width of the transition region is found to increase linearly with frequency but remains finite when extrapolated to zero frequency and temperature. Contrary to prevalent theoretical pictures, our data does not show the scaling characteristics of critical phenomena.These results suggest that a different mechanism governs the transition in our experiment.Comment: Minor changes and new references include
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