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  • 57Q45  (1)
  • Addition  (1)
  • Analytical Chemistry and Spectroscopy  (1)
  • Biochemistry and Biotechnology  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Letters in mathematical physics 23 (1991), S. 287-300 
    ISSN: 1573-0530
    Keywords: 57Q45
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Physics
    Notes: Abstract The elementary string interactions are the Reidemeister moves, birth/death, and fusion/fission. Such interactions have as their trace generically mapped surfaces, and these combine to form knotted surfaces in 4-space. The syzygies among these interactions are moves to such surfaces analogous to the Reidemeister moves for knots. ‘Movie’ parametrizations of these syzygies are given and interpreted in dimension 2+2. A Morse theoretic argument shows there are 15 such movie moves. These moves, with appropriate choices of crossing information, are sufficient to construct any isotopy of an embedded surface on which a height function has been specified. The first seven of the movie moves are parametrized versions of those given by Roseman. The remaining eight are moves of Δ-type. Amplitudes assigned to these interactions must satisfy relations that correspond to the movie moves. One such relation is a Zamolodchikov tetrahedral equation. We present some puzzles about the matrix formulations of these amplitudes.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Algorithmica 6 (1991), S. 49-71 
    ISSN: 1432-0541
    Keywords: Addition ; Area ; Time ; VLSI circuits ; Input/output ports ; Boundary layouts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract The complexity of adding twon-bit numbers on a two-dimensional systolic array is investigated. We consider different constraints on the systolic array, including: whether or not the input and output ports lie on the periphery of the array, constraints placed on the arrival and departure times of inputs and outputs . For all combinations of the above constraints, we obtain optimal tradeoffs among the resources of area, pipeline delay, and worst-case time. It turns out that there is a subtle interplay among the constraints and some of our results seem counterintuitive. For instance, we show that allowing more-significant bits to arrive earlier than less-significant bits can speed up addition by a factor of logn. We also show that multiplexing can often result in a smaller array. On the other hand, we show that some known results, such as Chazelle and Monier's bounds for arrays that have input/output ports on the perimeter, also hold in less constrained models.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 0887-3585
    Keywords: bioactivity ; SK-hep-1 hepatoma ; interleukin-1 ; recombinant protein ; crystals ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The gene for human interleukin-1β was cloned from SK-hep-1 hepatoma cellular RNA and expressed at high levels in Escherichia coli both as the naturally processed form (rIL-1β) and as a variant with an additional sequence of three amino acids on the N-terminus (rIL-1β+). Expressed protein was purified to homogeneity by a sequence of steps, which included low pH incubation, adsorption and desorption from Procion Red Sepharose, sizing on a Superose 12 fast-performance liquid chromatography (FPLC) column, and anion exchange chromatography on QAE Sepharose. The final step provided a biologically active protein that migrates on twodimensional (2-D) gels as a single spot with a pI of 6.7 ± 0.2 and a molecular mass of 17,500 daltons. Concentrated solutions of rIL-1β have produced crystals by ammonium sulfate precipitation. The crystals are tetragonal, show the symmetry of space group P41 or its enantiomer, have lattice constants of a = 58.46 (1) and c = 77.02 (3) A, and scatter to at least 2 Å resolution. A structure determination based on these crystals is under way.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Improved measurement of δ13C values of n-alcohols and sterols by gas chromatography/isotope ratio mass spectrometry is shown after their derivatization to silyl ethers. A method of correcting for the effects of the added silyl carbon atoms on the measurements of the silylated derivatives is also described and an application of the method for providing information on the sources of lacustrine n-alcohols and sterols is given.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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