Interactions in multicomponent systems containing surfactants. System silver iodide — methylene blue and sodium dodecyl sulphate

The precipitation and dissolution of AgI in the presence of methylene blue (MB · Cl) and sodium dodecyl sulphate (NaDS) was followed by X-ray diffraction analysis.At high MB · Cl concentration, the absence of AgI precipitates was observed, which is explained by considering the redox process MB⁺ + 2I^– MB^– + I₂. The decrease in I^– concentration causes dissolution or inhibition of growth of solid AgI which is significant at relatively high MB · Cl concentrations. The addition of NaDS causes the disappearance of these effects, which is explained by the incorporation of MB in NaDS micelles.These explanations are supported by the potentiometric measurements using Ag/Ag₂S and Pt electrodes.     

Infrared and Raman spectra of M2Cu2O5 (M=Y,Ho)

We report both Raman and infrared reflectivity spectra of M₂Cu₂O₅ (M=Y, Ho) at room temperature in the spectral range of 30–1000 cm^–1.37 (31) ir and 18 (15) Raman active modes of Y₂Cu₂O₅ (Ho₂Cu₂O₅) are observed. A factor group analysis has been performed to identify the symmetries of the observed modes. Comparing the vibrational spectra of these compounds we conclude that the phonons above 300 cm^–1 originate from the Cu–O vibrations and those under 300 cm^–1 from M–O vibrations.Alexander von Humboldt Foundation fellow     

Synthetic Antitumor Vaccines Containing MUC1 Glycopeptides with Two Immunodominant Domains-Induction of a Strong Immune Response against Breast Tumor Tissues

A shot in the arm for cancer treatment: Two MUC1 tetanus toxoid vaccines were synthesized and induced a strong immune response in mice. The antibodies elicited by the vaccines show a high selectivity for the tumor cells in mammary carcinoma tissues and also distinguish between tumor tissues at different stages.     

Photo-induced electron emission from 17beta-estradiol and progesterone and possible biological consequences

It was established for the first time, that the sexual hormones 17beta-estradiol (17betaE2) and progesterone (PRG) are able to emit electrons from their excited single state in water-ethanol mixtures. The yield of the "solvated electrons" (e(s)(-)) depends on the substrate concentration, the ratio of water-alcohol-mixtures and the temperature. The e(s)(-) yield obtained from 17betaE2 is by two orders of magnitude higher than this of PRG. The possible relationship of the resulting hormone transients from 17betaE2 leading via specific metabolites to breast cancer is discussed.     

The manganese ion of the heterodinuclear Mn/Fe cofactor in Chlamydia trachomatis ribonucleotide reductase R2c is located at metal position 1

The essential catalytic radical of Class-I ribonucleotide reductase is generated and delivered by protein R2, carrying a dinuclear metal cofactor. A new R2 subclass, R2c, prototyped by the Chlamydia trachomatis protein was recently discovered. This protein carries an oxygen-activating heterodinuclear Mn(II)/Fe(II) metal cofactor and generates a radical-equivalent Mn(IV)/Fe(III) oxidation state of the metal site, as opposed to the tyrosyl radical generated by other R2 subclasses. The metal arrangement of the heterodinuclear cofactor remains unknown. Is the metal positioning specific, and if so, where is which ion located? Here we use X-ray crystallography with anomalous scattering to show that the metal arrangement of this cofactor is specific with the manganese ion occupying metal position 1. This is the position proximal to the tyrosyl radical site in other R2 proteins and consistent with the assumption that the high-valent Mn(IV) species functions as a direct substitute for the tyrosyl radical.