Along with my usual weekly review of the published literature for new nuclear data, I also search for new candidates for best measurements of isotopic abundances from a single source. Most of the published articles, that I previously had found in the Research Library at the Brookhaven Lab, have already been sent to the members of the Atomic Weights Commission, by either Michael Berglund or Thomas Walczyk. In the last few days, I checked the published literature for any other articles in the areas of natural variations in isotopic abundance ratios, measurements of isotopic abundance ratios on samples of extra-terrestrial material and isotopic abundance ratio measurements performed using ICPMS instruments. Hopefully this information will be of interest to members of the Commission, the sub-committee on isotopic abundance measurements (SIAM), members of the former sub-committee on natural isotopic fractionation (SNIF), the sub-committee on extra-terrestrial isotope ratios (SETIR), the RTCE Task Group and the Guidelines Task Group, who are dealing with ICPMS and TIMS comparisons. In the following report, I categorize the publications in one of four areas. Measurements performed using either positive or negative ions with Thermal Ionization Mass Spectrometer, TIMS, instruments; measurements performed on Inductively Coupled Plasma Mass Spectrometer, ICPMS, …

In the 1949 Report of the Atomic Weights Commission, a series of new elements were added to the Atomic Weights Table. Since these elements had been produced in the laboratory and were not discovered in nature, the atomic weight value of these artificial products would depend upon the production method. Since atomic weight is a property of an element as it occurs in nature, it would be incorrect to assign an atomic weight value to that element. As a result of that discussion, the Commission decided to provide only the mass number of the most stable (longest-lived) known isotope as the number to be associated with these entries in the Atomic Weights Table. As a function of time, the mass number associated with various elements has changed as longer-lived isotopes of a particular elements has been found in nature, or as improved half-life values of an element's isotopes might cause a shift in the longest-lived isotope from one mass number to another. In the 1957 Report of the Atomic Weights Commission, it was decided to discontinue the listing of the mass number in the Atomic Weights Table on the grounds that the kind of information supplied by the mass number …

When the policy for determining the atomic weight values for the mononuclidic elements was changed some decades ago, it was argued that new atomic mass tables would only be produced about once a decade. Since 1977, the average has been once every nine years, which is consistent with that early estimate. This report summarizes the changes over the years for the atomic weight values of the mononuclidic elements. It applies the Commission's technical rules to the latest atomic mass table and recommends changes in the values of the Standard Atomic Weights for eleven of the twenty-two for the TSAW.

Cyclotides are a newly emerging family of large backbone cyclic polypeptides ({approx}30 residues long) characterized by a disulfide-stabilized core (3 disulfide bonds) with an unusual knotted structure. In contrast to other cyclic polypeptides, cyclotides have a well-defined three-dimensional structure. Therefore, despite their small size, they can be considered miniproteins. The unique cyclic-backbone topology and knotted arrangement of 3 disulfide bonds endow cyclotides with exceptional stability and resistance to chemical, enzymatic and thermal degradation. Furthermore, their well-defined structures have been associated with a range of biological functions. Together, these characteristics suggest that cyclotides are ideal molecular scaffolds for the development of stable peptide drugs. Despite the fact that the chemical synthesis of circular peptides has been well explored and a number different approaches involving solid-phase or liquid-phase exist, recent developments in the fields of molecular biology and protein engineering have now made possible the biosynthesis of cyclic peptides. This progress has been made mainly in two areas, non-ribosomal peptide synthesis and Expressed Protein Ligation (EPL)/protein trans-splicing. Access to biosynthetic cyclotides using recombinant DNA expression techniques offers the exciting possibility of producing large combinatorial libraries of highly stable miniproteins. This would allow the generation of cell-based combinatorial libraries that could be screened …