Pattern repetition

Interpretation of diffraction effects of non-crystalline substances. It has been pointed out in Chapter V that there is no sharp dividing line between crystalline and amorphous substances with decrease of crystal size, X-ray diffraction patterns become more and more diffuse until, finally, any attempt to calculate crystal size by the method given earlier in this chapter gives a figure of only a few Angstrom units— that is, about one unit cell in these circumstances the word crystal , with its implication of pattern repetition, is inappropriate. The alternative word amorphous is not entirely satisfactory either on account of the sizes of atoms and their preference for particular environments, the distribution of atomic centres.cannot be entirely random. The word non-crystalline is really preferable. 

Pattern Repetition is an effect in molecular RDF descriptors that leads to a unique pattern of distances originating from unique bond length between heteroatoms and carbon atoms, like C-S bridges. 

Barrn is caused by uneven tension in knitting, defective yam, improper needle action, or other similar factors that are not recognized until the fabric is dyed. It appears as a repetitive characteristic pattern of varying intensity that is easily recognizable. 

Crystals A crystal may be defined as a solid composed of atoms arranged in an orderly, repetitive array. The interatomic distances in a ciyst of any definite material are constant and are characteristic of that material. Because the pattern or arrangement of the atoms is repeated in all directions, there are definite restrictions on the lands or symmetry that crystals can possess. 

Coiled-coil a helices contain a repetitive heptad amino acid sequence pattern... 

Figure 3.2 Repetitive pattern of amino acids in a coiled-coil a helix.

Several silk fibroin genes have been cloned and sequenced and they all show a similar sequence pattern variable domains at the N- and C-termini flank a large region of repetitive short sequences of alternating poly-Ala (8 to 10 residues) and Gly-Gly-X repeats (where X is usually Ser, Tyr, or Gin). This middle region varies in length and may comprise up to 800 residues. 

Similarly, if the initial state consists of nothing but infinite repetitions of some invariant block of values, the space-time pattern will again be periodic. Figure 3.28, for example, shows sections of two infinite periodic patterns for elementary class rule R30, starting from the states -OlOl- and -OOlOOllOOlOOll- ... 

As mentioned above, which of the sequential NOEs d j, d j, and dj j is observed depends on the conformation of the backbone for the residues involved. Repetition of a particular type of connectivity for a sequence of amino acids often occurs in regions of regular secondary structure (19). For example a stretch of d jj-type NOEs is a signature of extended conformation, whereas a sequence of dj j -type NOEs is characteristic of helical conformation. Turns, on the other hand, are characterized by short, distinct patterns of dj j and d j connectivities. 

Cardioembolism Cardioembolism accounts for approximately 30% of all stroke and 25-30% of strokes in the young (age <45 years)." AF accounts for a large proportion of these strokes (15-25%). Symptoms may be suggestive, but they are not diagnostic. Repetitive, stereotyped, transient ischemic attacks (TIAs) are unusual in embolic stroke. The classic presentation for cardioembolism is the sudden onset of maximal symptoms. The size of the embolic material determines, in part, the course of the embolic material. Small emboli can cause retinal ischemic or lacunar symptoms. Posterior cerebral artery territory infarcts, in particular, are often due to cardiac embolism. This predilection is not completely consistent across the various cardiac structural abnormalities that predispose to stroke, and may be due to patterns of blood flow associated with specific cardiac pathologies. 

NOTE Group means SEM are shown an increase in spatial CV indicates a more repetitive pattern of movements in the BPM a decrease indicates a more highly varied pattern. 

Each figure represents the mean and standard error of three repetitions. The exudation pattern from the first 5 days of collection does not appear to differ from the second 5 days of collection. The relative levels of soyasapogenols and genistein within the root are not different at 15 days after germination, nor do they differ at 3 months of age. Soyasapogenols were not detected in shoot portions of seedlings. 

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