Networks, molecular

ROTATE Version 1.1 is available from Molecular Networks GmbH, Erlangen, Germany (http //www.mol-net.de). 

Two of the widely used programs for the generation of 3D structures are CONCORD and CORINA. CONCORD was developed by Pearlman and co-workers (17, 18] and is distributed by TRIPOS (19). The 3D-structure generator CORINA originates from Gasteiger s research group [20-23] and is available from Molecular Networks [24],... 

PETRA (calculation of physicochemical parameters) Molecular Networks GmbH, Nagelsbachstrasse 25, D-91052 Erlangen, Germany http //www.mol-net.de/ VolSurf Molecular Discovery Ltd., West Way House, Elms Parade, Oxford 0X2 9LL, UK http //www.moldiscovery.com/... 

PETRA Version 3 is available from Molecular Networks GmbH, Nagelsbachstr. 25, 91052 Erlangen, Germany (http //www.mol-nct.de) and can be tested via the Internet at http // www2.chemie.uni-eriangen.de/ sojiware/petra... 

Molecular Networks GmbH Naegelsbachstrasse 25 91052 Erlangen Germany... 

Boron is similar to carbon in that it has a capacity to form stable covalently bonded molecular networks. Carbonates, metalloboranes, phosphacarboranes, and other families comprise thousands of compounds. 

Classify substances as molecular, network covalent, ionic, or metallic. 

Fig. 2.1. Scheme of the molecular network of the studied polymers. The sequence of chemical groups is strictly as shown, although the molecular chains are randomly oriented in space... 

It is clear that even for the deformation of a molecular network in the absence of crystallisation, there is scope for significant theoretical developments. 

From the foregoing it is clear that indentation anisotropy is a consequence of high molecular orientation within highly oriented fibrils and microfibrils coupled with a preferential local elastic recovery of these rigid structures. We wish to show next that the influence of crystal thickness on AMH is negligible. The latter quantity is independent on 1 and is only correlated to the number of tie molecules and inter-crystalline bridges of the oriented molecular network. 

Now, we consider this phenomenon from the viewpoint of the non-Gaussian behavior of the network chain. As is well known, when we assume the idealized molecular network consisting... 

Figure 18.17 shows that the characteristics of the stress-strain curve depend mainly on the value of n the smaller the n value, the more rapid the upturn. Anyway, this non-Gaussian treatment indicates that if the rubber has the idealized molecular network strucmre in the system, the stress-strain relation will show the inverse S shape. However, the real mbber vulcanizate (SBR) that does not crystallize under extension at room temperature and other mbbers (NR, IR, and BR at high temperature) do not show the stress upturn at all, and as a result, their tensile strength and strain at break are all 2-3 MPa and 400%-500%. It means that the stress-strain relation of the real (noncrystallizing) rubber vulcanizate obeys the Gaussian rather than the non-Gaussian theory. 

In the case of amphiphilic molecules, characterized by the coexistence of spatially separated apolar (alkyl chains) and polar moieties, both parts cooperate to drive the intermolecular aggregation. This simple but pivotal peculiarity makes amphiphilic molecules soluble in both polar and apolar solvents and able to realize, in suitable conditions, an impressive variety of molecular aggregates characterized by spatially separated apolar and polar domains, local order at short times and fluidity at long times, and differences in size, shape (linear or branched chains, cyclic or globular aggregates, extended fractal-like molecular networks), and lifetime. 

Krauthammer M, Kaufmann CA, Gilliam TC, Rzhetsky A. Molecular triangulation bridging linkage and molecular-network information for identifying candidate genes in Alzheimer s disease. Proc Natl Acad Sci USA 2004 101 15148-53. 

Nikitin A, Egorov S, Daraselia N, Mazo I. Pathway stndio—the analysis and navigation of molecular networks. Bioinformatics 2003 19 2155-7. 

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