Groundwater contamination due to municipal solid waste landfills leachate is a serious environmental threat. During recent years, the use of stable isotopes as tracers identify groundwater phenomena has found application engineering. Deuterium (2H) and oxygen (18O) have successfully used if submitted interactions with leachate, significant organic amount. The paper shows two case studies, in ce...

Protein structure determination by solution NMR spectroscopy has long relied on the uniform stable isotopic enrichment with 13C and 15N to alleviate resonance overlap and to allow multiple distance and angular restraints, at as many atomic sites as possible, to facilitate computing the optimal three-dimensional structural model.(1) Recently, the optimization of these labeling techniques has inc...

Frequently as a result of experiments in which two isotopes are used one is left with a sequence of samples, the ratio of labeling in each sample, and the problem of analyzing the ratios. Suppose that the experiments are designed so that one expects uniform labeling except for one or two special groups of samples. The problem, then, is to find these groups. Because of the variability in the cou...

A series of photoswitchable, alpha-helical peptides were studied using two-dimensional infrared spectroscopy (2D-IR). Single-isotope labeling with (13)C(18)O at various positions in the sequence was employed to spectrally isolate particular backbone positions. We show that a single (13)C(18)O label can give rise to two bands along the diagonal of the 2D-IR spectrum, one of which is from an amid...

Infrared spectroscopy has long been used to examine the average secondary structure and orientation of membrane proteins. With the recent utilization of site-specific isotope labeling (e.g., peptidic 1-(13)C = (18)O) it is now possible to examine localized properties, rather than global averages. The technique of site-specific infrared dichroism (SSID) capitalized on this fact, and derives site...