Advances in microradiocarbon dating and the direct tracing of environmental carbon

Some important findings are presented concerning atmospheric carbon, particularly for those species having potential effects on climate and human health.     

Quantum mechanics in one band of a solid

The Bravais lattice operator and the quasimomentum are shown to form a complete set of conjugate operators in one band of a solid.     

Untersuchung der Kinetik der Sorption der L?sungsmitteld?mpfe durch Ionomere auf der Basis des Copolymerisats von Styrol und Acryls?ure

Ohne Zusammenfassung     

Spectrophotometric comparison of several reactions used for cerebrospinal fluid protein determinations

Three total protein procedures were analyzed by using spectral comparisons. Biuret reagent, Folin-Ciocalteau reagent, and Coomassie brilliant blue dye utilize different reactions to produce their final measured chromophores. Implicit in this statement is that there is no biuret component measured in the Folin-Ciocalteau color that is generated, for it is a reduced mixed heteropoly complex rather than a complex of copper with peptide bonds that is measured. The major conclusion of this study deals with the reliability of these three methods to effectively assay total protein mixtures in low-concentration solutions such as cerebrospinal fluid. Our results indicate that the biuret reaction is the least sensitive and the most linear while providing almost equal reactions on a weight per unit volume basis for albumin and gamma globulin as models. The Folin-Ciocalteau and Coomassie brilliant blue reactions are much more sensitive in absorbance signal generated, but they are nonlinear in calibration as well as unequal in their reactivities toward albumin and globulin. All of these factors must be carefully considered in making a choice of any of the three reactions for the analytical purposes intended.     

Notiz zur Synthese des Nonactins

With (?)-nonactic acid and the 8-epitosylate of benzyl (+)-nonactate usingWalden inversion (?)-nonactyl-(+)-nonactic acid is constructed. The latter forms by way of its imidazolide or its α-mercaptopyridyl ester the macrotetrolide nonactine in poor yield.     

Interaction of hemoglobin in elevated serum total bilirubin determinations

A spectrophotometric study was carried out in an effort to elucidate how hemoglobin in serum interferes in the diazo coupling reaction used for the determination of bilirubin. Because it is difficult to see hemoglobin in neonatal specimens in which bilirubin is elevated without obtaining spectra of the mixtures, this can be a real problem when handling these specimens while using this particular reaction. From the spectrophotometric evidence described here, one can infer that hemoglobin can act in two ways. In one way, the formation of ferriprotoporphyin generates an oxidizing agent which can convert bilirubin to an oxidized product precluding it from taking part in a diazo coupling reaction. In the other way, the same ferriprotoporphyrin seems capable of oxidizing the azobilirubin complex after it has reached equilibrium again causing some lowering of the results obtained. It may be reasonable to assume that the quicker the analytical event can occur, the more accurate the result might be. If the matrix of reaction can be changed, and the reaction of diazo coupling also speeded up as a feature of the change, then it may be possible to avoid the interference from hemoglobin almost entirely. High concentrations of hemoglobin were tested here in an attempt to clearly show how the interference might take place.