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Nelson A Belitsky JM Vidal S Joiner CS Baum LG Stoddart JF 《Journal of the American Chemical Society》2004,126(38):11914-11922
A self-assembled pseudopolyrotaxane consisting of lactoside-displaying cyclodextrin (CD) "beads" threaded onto a linear polyviologen "string" was investigated for its ability to inhibit galectin-1-mediated T-cell agglutination. The CDs of the pseudopolyrotaxane are able to spin around the axis of the polymer chain as well as to move back and forth along its backbone to alter the presentation of its ligand. This supramolecular superstructure incorporates all the advantages of polymeric structures, such as the ability to span large distances, along with a distinctively dynamic presentation of its lactoside ligands to afford a neoglycoconjugate that can adjust to the relative stereochemistries of the lectin's binding sites. The pseudopolyrotaxane exhibited a valency-corrected 10-fold enhancement over native lactose in the agglutination assay, which was greater than the enhancements observed for lactoside-bearing trivalent glycoclusters and a lactoside-bearing chitosan polymer tested using the same assay. The experimental results indicate that supramolecular architectures, such as the pseudopolyrotaxane, provide tools for investigating protein-carbohydrate interactions. 相似文献
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We construct a superpropagator in maximally supersymmetric Yang–Mills theory which is invariant off-shell under a chiral half of supersymmetries. Motivated by the duality with scattering amplitudes in this theory, we apply this superpropagator to supersymmetric Wilson loop on polygonal contours. By performing explicit one-loop calculations we confirm the absence of anomalies and verify the duality between the object under study and NMHV amplitudes. 相似文献
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We present a coupled decreasing sequence of random walks on Z that dominate the edge process of oriented bond percolation in two dimensions. Using the concept of random walk in a strip, we describe an algorithm that generates an increasing sequence of lower bounds that converges to the critical probability
of oriented percolation pc. From the 7th term on, these lower bounds improve upon 0.6298, the best rigorous lower bound at present, establishing 0.63328
as a rigorous lower bound for pc. Finally, a Monte Carlo simulation technique is presented; the use thereof establishes 0.64450 as a non-rigorous five-digit-precision (lower) estimate
for pc.
Mathematics Subject Classification (1991): 60K35
Supported by CNPq (grant N.301637/91-1).
Supported by a grant from CNPq. 相似文献
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Self-assembled multivalent pseudopolyrotaxanes, composed of lactoside-bearing cyclodextrin (CD) rings threaded on linear polyviologen polymers, have been introduced recently as flexible and dynamic neoglycoconjugates. In the course of this research, it was found that polyviologens are responsive to the Bradford assay, which is traditionally highly selective for proteins. The response of the pseudopolyrotaxanes to the Bradford assay was dependant on, and thus indicative of, the degree of threading of the CD rings onto the polyelectrolyte. The assay was then used to report on the threading and dethreading of native and lactoside-bearing alpha-CD rings onto and off of polyviologen chains, a phenomenon which demonstrates the utility of biochemical assays to address problems unique to supramolecular chemistry. 相似文献
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Gurioli M. Bogani F. Vinattieri A. Colocci M. Belitsky V. I. Cantaredo A. Pavlov S. T. 《Il Nuovo Cimento D》1995,17(11):1487-1492
Il Nuovo Cimento D - A detailed study of the relative role played by localized and/or propagating intermediate excitonic states in, resonant Rayleigh scattering (RRS) is presented for a large set... 相似文献
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Vladimir Belitsky 《Journal of statistical physics》1993,70(5-6):1233-1254
We study an interacting particle system on a one-dimensional infinite lattice and one-dimensional lattices with a periodic boundary. In this system, each site of the lattice may be either empty or occupied and initially all the lattice sites are empty. The evolution of the system is defined as follows: an empty site waits an exponential time with mean 1 and becomes occupied, and an occupied site becomes empty at a time which is distributed exponentially with mean
k, wherek is the number of occupied neighboring sites of this site in the current state of the system. We show that the mean number of the occupied sites of the lattice, considered as a function of time, may possess a convex part. A sufficient condition for this is that
0 is large and
k,k1, are small. The studied system has been proposed recently as a mathematical model of certain deposition processes, in particular those which exhibit nucleation caused by lateral attractive interaction between the deposited molecules. Our research was motivated by the observation that the density of deposited molecules contains a convex part, over some time interval, if the attractive forces are strong, while this density is a concave function of time if these forces are weak or absent. Our result agrees with this observation. 相似文献
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