Link, Kuhn

Here, b denotes the Kuhn s statistical segment length. The network is represented by a huge chain internally cross-linked at cross-linking points where it touches and at the surfaces of Mf filler particles. The point-like local cross-hnk constraints are easy to handle and can be represented by the term... 

Kuhn H., Demidov V., Frank-Kame-NETSKii M. D. An earring for the double helix Assembly of topological links comprising duplex DNA and a circular oligonucleotide. J. Biomol. Struct. Dyn. 2000 2 221-225. 

As early as 1972, Kuhn described a model in which he assumed that RNA replication with a certain error rate could have occurred without the participation of enzymes. Natural phenomena with cyclic behaviour are an important factor in Kuhn s thinking these drive duplication processes. Examples are summer and winter, day and night, or high and low tide (whereby the latter were probably subject to greater variations on the primeval Earth than they are today). These rhythms were often linked with considerable temperature variations, which, for example, made possible the transition from double to single strand RNA (and vice versa). It can be assumed that the cyclic variations involved reactions in which monomers were linked to form polymers. 

Expressions for the optical anisotropy AT of Kuhn s random link (an equivalent to the stress-optical coefficient) of stereo-irregular and multirepeat polymers are derived on the basis of the additivity principle of bond polarizabilities and the RIS approximation for rotations about skeletal bonds. Expressions for the unperturbed mean-square end-to-end distance , which are required in the calculation of Ar, are also obtained. 

Segmental orientation in model networks of PDMS in uniaxial tension is measured by infrared dlchroism, Measurements are made for four tetrafunctlonal end-linked networks. Results of experiments are compared with predictions of calculations based in (i) the widely used Kuhn expression and (ii) the RIS formalism. The Kuhn expression is found to considerably overestimate the segmental orientation. The RIS approach leads to values of segmental orientation that fall between predictions of the affine and phantom network models. This indicates that the nematic-like Intermolecular contributions to orientation are not significant. 

Such structuring is necessarily an intermolecular effect. The simplest type of an intermolecular effect, which should be treated first, is due to the crosslinks between the chains themselves. Dobson and Gordon (50) have remarked that most crosslinks are actually short chains of one or several links, which upon straining the network, become oriented but cannot be stretched. As a result an additional entropy force should arise, which has not yet been accounted for in the Gaussian theory. This force can be calculated on the basis of the Kuhn and Grun (114) chain vector orientation argument, which yields in extension... 

In preceding sections it has tacitly been assumed that the behaviour of a real chain molecule can be described with the aid of a chain consisting of Z randomly jointed links each of length A. In fact, this model is so well-known that only some additional remarks will be made. The original equations of Kuhn (62) and of Kuhn and GrOn (64) read ... 

Than, M. E., Henrich, S., Huber, R., Ries, A., Mann, K., Kuhn, K., Timpl, R., Bourenkov, G. P., Bartunik, H. D., and Bode, W. (2002). The 1.9-A crystal structure of the non-collagenous (NCI) domain of human placenta collagen IV shows stabilization via a novel type of covalent Met-Lys cross-link. Proc. Natl. Acad. Sci. USA 99, 6607-6612. 

Richard Kuhn Prize, Chemistry, 1937, carotenoids, FMN-linked Glucose... 

Tellinghuisen, T. L., Perera, R., and Kuhn, R. J. (2001). In vitro assembly of Sindbis virus core-like particles from cross-linked dimers of truncated and mutant capsid proteins./. Virol. 75, 2810-2817. 

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