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Strong Resemblance (strong + resemblance)
Selected AbstractsNanocomposite Synthesis: Embryonic States of Fluorapatite,Gelatine Nanocomposites and Their Intrinsic Electric-Field-Driven Morphogenesis: The Missing Link on the Way from Atomistic Simulations to Pattern Formation on the Mesoscale (Adv. Funct.ADVANCED FUNCTIONAL MATERIALS, Issue 22 2009Mater. Fractal aggregates of fluorapatite,gelatine nanocomposites (SEM image taken by Yigit Öztan, MPI CPfS),which bears a strong resemblance to the biosystem hydroxyapatite,collagen, a key material in human bones and teeth,are formed from bundles of calcified protein molecules representing the first (embryonic) states of shape development and leading to extended processes of self-organisation. This process has been studied in detail by P. Simon et al., and is reported on page 3596. [source] Grafting of polyolefins with maleic anhydride: alchemy or technology?MACROMOLECULAR SYMPOSIA, Issue 1 2003Martin van Duin Abstract Nowadays, the process of maleic anhydride (MA) grafting and the application of MA-grafted polyolefins are viewed as mature technologies. The chemistry and technology of modifying apolar polyolefins with the polar and reactive MA either in solution or in the melt were already explored as far back as the 1950s. Commercial applications exploit the improved adhesion of polyolefins to polar materials, both at the macroscopic scale and on the microscopic scale. However, it is hardly recognised that, from a scientific point of view, grafting has still a strong resemblance to alchemy. Both process and application technologies have been developed in a trial and error fashion. Only in the last decade the structure of MA-grafted polyolefins has been elucidated and attempts to "look" inside the extruder during grafting were only recently successful. The first steps towards the development of sound chemical models are currently made. An overview will be given of the progress made in the various areas mentioned. [source] Superspace description of the modulated structure of the metal-salt-hybrid Bi7,,,,Ni2Br5,,,2, (, = 1/9)ACTA CRYSTALLOGRAPHICA SECTION B, Issue 5 2009B. Wahl The compound Bi7,,,,Ni2Br5,,,2, = (Bi3Ni)2[Bi1,,,,Br4]Br1,,2, (, = 1/9) is a sub-bromide of the intermetallic phase Bi3Ni. Its crystal structure contains metallic rods, [Bi3Ni], which are embedded in a salt-like matrix of bromido-bismuthate(III) and bromide anions. The non-stoichiometry originates from the variation of the number n of trans edge-sharing octahedra in the [BinBr4n,+,2](n,+,2), oligomers (3 ,n, 5), as well as from vacancies on the sites of the isolated Br atoms. The simplified structure is described in the orthorhombic space group Cmcm with a = 4.0660,(4), b = 23.305,(3), c = 17.130,(2),Å. It shows a statistical distribution of vacancies and orientational disorder of the concatenated octahedra. By choosing the modulation vector q = a*/9 + b*/2, the additional weak reflections of the diffraction pattern can be indexed. In the [3,+,1]-dimensional superspace group Pmnm(,½0)000, an ordered structure model is achieved. The modulated crystal structure bears a strong resemblance to the somewhat higher oxidized sub-bromide Bi7,,,,Ni2Br5 (, = 1/9). [source] Structure of a putative ,-phosphoglucomutase (TM1254) from Thermotoga maritimaACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 12 2009Richard W. Strange The structure of TM1254, a putative ,-phosphoglucomutase from T. maritima, was determined to 1.74,Å resolution in a high-throughput structural genomics programme. Diffraction data were obtained from crystals belonging to space group P22121, with unit-cell parameters a = 48.16, b = 66.70, c = 83.80,Å, and were refined to an R factor of 19.2%. The asymmetric unit contained one protein molecule which is comprised of two domains. Structural homologues were found from protein databases that confirmed a strong resemblance between TM1254 and members of the haloacid dehalogenase (HAD) hydrolase family. [source] Innate aversion to ants (Hymenoptera: Formicidae) and ant mimics: experimental findings from mantises (Mantodea)BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 1 2006XIMENA J. NELSON Field data suggest that ants may be important predators of mantises which, in turn, may be important predators of jumping spiders (Salticidae). Using a tropical fauna from the Philippines as a case study, the reactions of mantises to ants, myrmecomorphic salticids (i.e. jumping spiders that resemble ants) and ordinary salticids (i.e. jumping spiders that do not resemble ants) were investigated in the laboratory. Three mantis species (Loxomantis sp., Orthodera sp., and Statilia sp.) were tested with ten ant species, five species of Myrmarachne (i.e. myrmecomorphic salticids), and 23 ordinary salticid species. Two categories of the myrmecomorphic salticids were recognized: (1) ,typical Myrmarachne' (four species with a strong resemblance to ants) and (2) Myrmarachne bakeri (a species with less strong resemblance to ants). Ants readily killed mantises in the laboratory, confirming that, for the mantises studied, ants are dangerous. In alternate-day testing, the mantises routinely preyed on the ordinary salticids, but avoided ants. The mantises reacted to myrmecomorphic salticids similarly to how they reacted to ants (i.e. myrmecomorphic salticids appear to be, for mantises, Batesian mimics of ants). Although myrmecomorphic salticids were rarely eaten, M. bakeri was eaten more often than typical Myrmarachne. Because the mantises had no prior experience with ants, ant mimics or ordinary salticids, our findings suggest that mantises have an innate aversion to attacking ants and that this aversion is generalized to myrmecomorphic salticids even in the absence of prior experience with ants. © 2006 The Linnean Society of London, Biological Journal of the Linnean Society, 2006, 88, 23,32. [source] Decomposition of Net Final Values: Systemic Value Added and Residual IncomeBULLETIN OF ECONOMIC RESEARCH, Issue 2 2003Carlo Alberto Magni This paper proposes a model aiming at decomposing the Net Final Value of a project under certainty. It makes use of a systemic outlook: the investor's net worth is regarded as a dynamic system whose structure changes over time. On this basis, a profitability index is presented, here named Systemic Value Added (SVA), which lends itself to a periodic decomposition: the periodic shares formally translate the economic concept of residual income (or excess profit). While as an overall index the Systemic Value Added coincides with the Net Final Value (NFV) of an investment, the systemic partition of a SVA is shown to differ from the NFV decomposition model proposed by Peccati (1987, 1991, 1992), which in turn bears a strong resemblance to Stewart's (1991) EVA model. The SVA model and the NFV,based model bear interesting relations: by introducing the concept of a shadow project the SVA model can be re,shaped so that the decomposition of the SVA can be accomplished by applying Peccati's argument to the shadow project, or, which is the same, by computing the shadow project's Economic Value Added. The paper then generalizes the approach allowing for a portfolio of projects, multiple debts and multiple synchronic opportunity costs of capital, for which a tetra,dimensional decomposition is easily obtained. [source] Structural, Functional and Calorimetric Investigation of MosA, a Dihydrodipicolinate Synthase from Sinorhizobium meliloti L5,30, does not Support Involvement in Rhizopine BiosynthesisCHEMBIOCHEM, Issue 10 2008Christopher P. Phenix Dr. Abstract MosA is an enzyme from Sinorhizobium meliloti L5,30, a beneficial soil bacterium that forms a symbiotic relationship with leguminous plants. MosA was proposed to catalyze the conversion of scyllo -inosamine to 3- O -methyl- scyllo -inosamine (compounds known as rhizopines), despite the MosA sequence showing a strong resemblance to dihydrodipicolinate synthase (DHDPS) sequences rather than to methyltransferases. Our laboratory has already shown that MosA is an efficient catalyst of the DHDPS reaction. Here we report the structure of MosA, solved to 1.95 Å resolution, which resembles previously reported DHDPS structures. In this structure Lys161 forms a Schiff base adduct with pyruvate, consistent with the DHDPS mechanism. We have synthesized both known rhizopines and investigated their ability to interact with MosA in the presence and absence of methyl donors. No MosA-catalyzed methyltransferase activity is observed in the presence of scyllo -inosamine and S -adenosylmethionine (SAM). 2-Oxobutyrate can form a Schiff base with MosA, acting as a competitive inhibitor of MosA-catalyzed dihydrodipicolinate synthesis. It can be trapped on the enzyme by reaction with sodium borohydride, but does not act as a methyl donor. The presence of rhizopines does not affect the kinetics of dihydrodipicolinate synthesis. Isothermal titration calorimetry (ITC) shows no apparent interaction of MosA with rhizopines and SAM. Similar experiments with pyruvate as titrant demonstrate that the reversible Schiff base formation is largely entropically driven. This is the first use of ITC to study Schiff base formation between an enzyme and its substrate. [source] | |||||||||||||