Signature similarity

In a vibration analysis, roll misalignment generates a signature similar to classical parallel misalignment. It generates dominant frequencies at the fundamental (lx) and second (2x) harmonic of running speed. 

Only a few Pb isotope measurements have been made on deep ice cores and these show signatures similar to Greenland. Neodymium and Sr isotopes have been made on LGM-dust from East Antarctica to identify its origin. The results identify a South American (Patagonian) source for this dust, although further investigation is needed to determine the transport mechanisms. 

There are no reports of krypton isotope anomalies in arc-related terrains— the small number of krypton isotopic analyses (e.g., Patterson et al. 1994) reveal only atmospheric-like ratios. For the most part, the situation is similar for xenon—atmospheric-like ratios dominate the few analyses reported. An exception is found in the work of Nakai et al. (1997) which reports two samples from the vicinity of Mt. Etna with enrichments in both Xe and Xe relative to air. The anomalies are correlated such that they appear to reflect mixing between air and an enriched source with a xenon isotope signature similar to MORE. 

The fluids from the zone I display a halogen signature similar to that obtained for magmatic fluids. Thus, a magmatic source for these fluids can be considered. In addition, the high salinity indicated by the presence of salt crystals in the... 

This paper will address three subjects a) carbon isotopic composition of bone carbonate b) the possible role of hpid metabolism in determining frae-tionation between bone carbonate and collagen and its apparent trophic signature and c) concepts of routing of carbon isotopes in the body, especially from protein foods to collagen. The discussion will be limited to carbon isotope ratios C C/ C), although we appreciate that N/ N ratios, which are also very useful in determining trophic levels and somces of protein, present similar biochemical problems. 

Recently, a / -dodecapeptide was found to display a CD spectrum in water which was very similar to that assigned to the 12/10-helix, with a single maximum near 200 nm. Careful NMR analysis however, revealed a predominantely extended conformation without regular secondary structure elements [174]. This result stresses that the CD signature assigned to the 12/10-structure might not be unique and again (see Section 2.2.3.1) that CD spectra must be interpreted with caution. 

Surprisingly, in contrast to a- and y9-peptides, CD spectra of y-peptides gave only a very hmited amount of stmctural information. Experiments conducted on heh-cal y" -hexapeptides did not reveal any characteristic CD signature (no Cotton effect) [200, 201]. Similarly, y -peptides built from 2,4-disubstituted y-amino acids of like configuration and shown to adopt a more stable 2.6-helical structure, do not display typical CD curves either [201]. However, CD spectra of the 2.6-helical -peptide 147 and its Boc-protected derivative recorded in MeOH and CD3CN present an intense maximum around 215 nm with a shoulder at ca. 200 nm [207]. 

Although the n-n and tz-tz electronic transitions of the urea chromophore have not been studied as extensively as amides, the contribution of the backbone is expected to dominate the far UV spectra of oligoureas in a fashion similar to that which is observed for peptides. The CD spectra recorded in MeOH of oligoureas 177 and 178 show an intense maximum near 204 nm (Figure 2.48). This is in contrast to helical y" -peptides that do not exhibit any characteristic CD signature. 

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