EDGE LOOP

The first indication that several conformations could be observed came from the comparison of the NMR solution and an earlier X-ray structure of the Oxytricha bimolecular quadruplex. The initial X-ray structure contained many of the features found in the solution structure but differed in the orientation of the thymine loops edge-loops were observed by X-ray as compared to diagonal-loops in the NMR structure. However, a recent analysis corrected this earlier crystallographic study and demonstrated that this quadruplex adopts a structure with two strands forming an antiparallel diagonal arrangement, indicating that the native structure is the same in solution and in the crystalline state. 

In the reaction graph G j those edges/loops that are cancelled (formed) are evaluated by -1 (+1). 

Deleting a preselected vertex and edges/loops that are incident with the vertex. 

Deleting a preselected edge/loop, where the vertices incident with the edge/loop remain in the graph. 

The important fact to note at this point is that, since metadislocation loops have [0 01] Burgers vectors, they are pure edge loops, also referred to as prismatic loops [3], that is, they possess only edge-type and no screw type segments. 

In the previous section, we have identified metadislocations as loops with (001) habit planes and [001] Burgers vectors. They are pure edge loops, which can only expand and contribute to strain, if their segments move by climb. Glide motion of the segments would merely lead to unaltered movement of the loop along its ghde cylinder, which does not contribute to strain. 

EDGE, LOOP, FACE, SHELL,INDEX ENTRY) ... 

A B REP is an entity that has a scope. A B REP may have a material property associated with it. The B REP is a self-contained entity in the sense that no entity in the B REP may refer to an entity outside the scope of the B REP. All referenced entities must be within the B REP scope itself. The scope of a B REP contains both topological and geometrical entities. Geometry is represented by lists of the entities POINT, DIRECTION, EDGE CURVE and FACE SURFACE which are referenced by the topological entities defined subsequently. Topology is represented by lists of the entities, VERTEX, EDGE, LOOP, FACE and SHELL in that order so that no entity is referenced before it is defined. 

ENTITY LOOP = CLASS ( EDGE.LOOP, VERTE5CL00P ) = ... 

A loop must be either a VERTEX.L00P or an EDGE.LOOP. 

Every reference to an EDGE in an EDGE.LOOP has an ORIENTATION flag associated with it, to indicate whether the sense of the EDGE in the LOOP coincides with the sense of the LOOP. The ORIENTATION flag is. T. if the senses coincide otherwise its. F.. 

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