Cooperative action

Von Neumann recognized this problem, of course. His solution was to essentially use the cooperative action of several automata to effectively copy a machine s blueprint. He first introduced a copier automaton M that copies whatever blueprint B it is given. Next, he defined an automaton A" that inserts a copy of B into the... 

Shimidzu, T. Cooperative Actions in the Nucleophile-Containing Polymers. Vol. 23, pp. 55 to 102. 

When esterase models are designed, several important and fundamental problems have to be solved. Systematic studies on other interactions, such as hydrogen-bonding and charge-transfer type forces have not been fully performed. Furthermore, various cooperative actions between different kinds of interactions, e. g. the correlation between the attraction of substrate and repulsion of a product by a polyelectrolyte catalyst, has not yet been carried. 

Sharkey, W. H. Polymerizations Through the Carbon-Sulphur Double Bond. VoL 17, pp. 73-103. Shimidzu, T. Cooperative Actions in the Nucleophile-Containing Polymers. Vol. 23, pp. 55-102. Slichter, W. P. The Study of High Polymers by Nuclear Magnetic Resonance. VoL 1, pp. 35-74. Small, P. A. Long-Chain Branching in Polymers. VoL 18,pp. 1-64. 

Shimidzu, I. Cooperative Actions in the Nucleophile-Containing Polymers. Vol. 23, pp. 55-102. Shutov, F. A. Foamed Polymers Based on Reactive Oligomers, Vol. 39, pp. 1-64. 

In any solvent system, the essential factors required for dissolution of cellulose include adequate stabihty of the electrolyte/solvent complex cooperative action of the solvated ion-pair on hydrogen bonding of cellu-... 

It has become increasingly evident, however, that management of Great Lakes resources to provide sustainable benefits cannot be achieved by the cooperative action of governments alone. Despite admirable efforts carried out under the Canada/United States Water Quality Agreements, problems continue to persist and many important resources continue to be depleted both qualitatively and quantitatively. Collective action on the part of all users of the lakes will be required if the Great Lakes are to be restored and protected for the benefit of future generations. 

It has been suggested by Ikegami (1968) that the carboxylate groups of a polyacrylate chain are each surrounded by a primary local sphere of oriented water molecules, and that the polyacrylate chain itself is surrounded by a secondary sheath of water molecules. This secondary sheath is maintained as a result of the cooperative action of the charged functional groups on the backbone of the molecule. The monovalent ions Li", Na and are able to penetrate only this secondary hydration sheath, and thereby form a solvent-separated ion-pair, rather than a contact ion-pair. Divalent ions, such as Mg " or Ba +, cause a much greater disruption to the secondary hydration sheath. 

The extent of ion binding depends on a number of characteristics of the polyion degree of dissodation, acid strength, conformation, distribution of ionizable groups and cooperative action between these groups (Wilson Crisp, 1977 Oosawa, 1971 Harris Rice, 1954, 1957). The hydration state of the macromolecule, which is in turn dependent on conformation, also affects ion binding (Begala, 1971). 

I) Complex through Cooperative Action of Hydrogen Bonding and Auriophilicity. Journal of the American Chemical Society, 119(34), 8115-8116. 

The mononuclear mechanism is similar to the one proposed for platinum-catalyzed hydrophosphination of formaldehyde (Scheme 5-3), but also includes a second P-C bond-forming pathway nucleophilic (Michael) attack of the phosphido ligand on coordinated acrylonitrile. The binuclear mechanism is similar, but P-C bond formation is proposed to occur by cooperative action of two Pt centers, with complexes 4 - 6 as possible intermediates [8]. 

A proposed mechanism (Scheme 5-44) begins with deprotonation of dimethyl phosphite to give an Al-phosphito complex (32) which can react with the aldehyde via either a chelate or open transition state, the latter possibly involving cooperative action of two aluminum centers, consistent with the observation of co-catalysis. Following P-C bond formation, several possible rearrangements could regenerate the achve catalyst and form the product... 

The National Research Council has recognized the importance of the food protection problem and the need for an organization to provide technical counsel on the utilization of new materials in the production and processing of foods. The desirability of cooperative action by industry, government, and other research organizations in providing the scientific guidance required for the protection of the food supply has been emphasized. 

Tigerschoid and Ilmoni (T3) attributed the high degree of compaction attained by the granule to a cooperative action of the negative capillary... 

One possible mechanism responsible for cooperative action of antioxidants is reduction of a semi-oxidized carotenoid by another antioxidant. Carotenoid cation radicals can be reduced, and therefore recycled to the parent molecule, by a-tocopherol, ascorbate, and melanins (Edge et al., 2000b El-Agamey et al., 2004b) (Figure 15.5). Interestingly, lycopene can reduce radical cations of other carotenoids, such as astaxanthin, (3-carotene, lutein, and zeaxanthin (Edge et al., 1998). 

The above finding led to another interesting conclusion that a minimum chain length is essential for PEG to form a stable complex with a-CD. The chain length selectivity implies that some cooperative action is involved in this complex formation as is well known in the complex formation of PEG with hydrogen-donor polymers such as poly(acrylic acid). 

Shinkai et al. described the synthesis of dendritic saccharide sensors based on a PAMAM dendrimer labeled with eight boronic acid residues [183]. The dendritic compound showed enhanced binding affinity for D-galactose and d-fructose. The fact that the dendritic boronic acid functions as a saccharide sponge is ascribed primarily to the cooperative action of two boronic acids to form an intramolecular 2 1 complex. When one boronic acid binds a saccharide, its counterpart cannot participate in dimer formation and seeks a guest. 

Yang W, Yan J, Fang H et al (2003) The first fluorescent sensor for D-glucarate based on the cooperative action of boronic acid and guanidinium groups. Chem Commun 792-793... 

Fig. 10.36. Recognition of uronic and sialic acid salts by the cooperative action of boronic acid and zinc chelate (Yamamoto M. et al. (1996) Tetrahedron 54, 3125).

Special attention has been paid to acid-catalyzed ring expansion. Sterba and Haensel (J19) reported that the rate of benzene formation from methyl-cyclopentane increases with increasing fluorine content of the catalyst (up to 1.0% F with 0.3% Pt on alumina). At the same time, increasing platinum content also promoted this reaction (up to 0.075% Pt with 0.77% F on alumina). This indicates the remarkable cooperative action of a dual function catalyst (119, p. 11). 

Because of the fractional R-Li bond, clusters and polymers can reversibly form an open cluster, which traps the unsaturated substrate through multiple-point bonding (cf Schemes 10.5 and 10.7). Lithium cations assist the electron flow from the cuprate to the electrophile and, to achieve such cooperative action, a cluster of a particular size may be necessary. Lewis acid metals other than lithium (Zn , for example) will also play similar roles. 

A new PET-based chemosensor for uronic and sialic acids utilizing the cooperative action of boronic acid and metal chelate was reported by Shinkai and co-workers. This group synthesized a novel fluorescent chemosensor molecule bearing both an o-aminomethylphenylboronic acid group for diol binding to a saccharide and a l,10-phenanthroline-Zn(II)chelate moiety for the carboxylate binding, which enables this sensor to discriminate between neutral monosaccharides and acidic compounds [110],... 

This paper will review the literature on the cooperative action of known allelochemicals. It will also focus on the increasing evidence that the biological importance of these substances, especially in low concentrations, depends on associated environmental conditions. 

We designed experiments to determine if residual concentrations of atrazine and near-threshold levels of phenolic acids have a cooperative action (51). Procedures in these studies were similar to the ones used in investigations described earlier for determining moisture-allelochemical interference, except oat (Avena sativa L.) seedlings were utilized and these were treated 9 days after germination. Ferulic acid was chosen as a representative allelochemical. Treatments of atrazine and ferulic acid were made as amendments to the nutrient solution in which the oat plants were grown. 

Synergism Cooperative action of substances whose total effects is greater than the sum of their separate effects. 

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