8,275 research outputs found

    An Inter-molecular Adaptive Collision Scheme for Chemical Reaction Optimization

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    Optimization techniques are frequently applied in science and engineering research and development. Evolutionary algorithms, as a kind of general-purpose metaheuristic, have been shown to be very effective in solving a wide range of optimization problems. A recently proposed chemical-reaction-inspired metaheuristic, Chemical Reaction Optimization (CRO), has been applied to solve many global optimization problems. However, the functionality of the inter-molecular ineffective collision operator in the canonical CRO design overlaps that of the on-wall ineffective collision operator, which can potential impair the overall performance. In this paper we propose a new inter-molecular ineffective collision operator for CRO for global optimization. To fully utilize our newly proposed operator, we also design a scheme to adapt the algorithm to optimization problems with different search space characteristics. We analyze the performance of our proposed algorithm with a number of widely used benchmark functions. The simulation results indicate that the new algorithm has superior performance over the canonical CRO

    ISOLATION OF CHROMATIN THREADS FROM THE RESTING NUCLEUS OF LEUKEMIC CELLS

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    1. A method for the separation of chromatin threads from the resting nucleus of leukemic cells has been described. 2. The isolation of the chromatin strands was accomplished by purely mechanical means, and the separation, including extraction and purification in the centrifuge, required only about 1 hour. 3. Evidence is presented to show that the chromatin strands are morphologically related to the chromosomes, if not identical. 4. It seems probable that, by the present technique, chromatin strands can be obtained from different mammalian tissues for direct microscopical examination and biochemical analysis

    Centralizing the International Operations of Multinationals

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    The thesis to this Article is that, ideally, international decision making should be managed from a central control point, leaving day-to-day management and operational control within each of the operating locations. The purpose of the central location would be, basically, to get an overview of the world, to put together the pieces of the global enterprise in such a manner as to be able to take advantage of the shifting trade, financial, monetary and development whims of not only the free world but, more recently, the communist world which is wont to enter the international monetary and development markets in a major way

    Probing metal ion binding and conformational properties of the colicin E9 endonuclease by electrospray ionization time-of-flight mass spectrometry

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    Nano-electrospray ionization time-of-flight mass spectrometry (ESI-MS) was used to study the conformational consequences of metal ion binding to the colicin E9 endonuclease (E9 DNase) by taking advantage of the unique capability of ESI-MS to allow simultaneous assessment of conformational heterogeneity and metal ion binding. Alterations of charge state distributions on metal ion binding/release were correlated with spectral changes observed in far- and near-UV circular dichroism (CD) and intrinsic tryptophan fluorescence. In addition, hydrogen/deuterium (H/D) exchange experiments were used to probe structural integrity. The present study shows that ESI-MS is sensitive to changes of the thermodynamic stability of E9 DNase as a result of metal ion binding/release in a manner consistent with that deduced from proteolysis and calorimetric experiments. Interestingly, acid-induced release of the metal ion from the E9 DNase causes dramatic conformational instability associated with a loss of fixed tertiary structure, but secondary structure is retained. Furthermore, ESI-MS enabled the direct observation of the noncovalent protein complex of E9 DNase bound to its cognate immunity protein Im9 in the presence and absence of Zn2+. Gas-phase dissociation experiments of the deuterium-labeled binary and ternary complexes revealed that metal ion binding, not Im9, results in a dramatic exchange protection of E9 DNase in the complex. In addition, our metal ion binding studies and gas-phase dissociation experiments of the ternary E9 DNase-Zn2+-Im9 complex have provided further evidence that electrostatic interactions govern the gas phase ion stability
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