No abstract

Vapor quenching in the phase-separating Ag-Ni system creates alloys that appear homogeneously amorphous under conventional probes. However, an atomic-level structural analysis based on extended x-ray absorption fine structures in combination with reverse Monte Carlo and molecular dynamics simulations demonstrates that these new phases are characterized by nonuniform, spinodal-like structures on an extremely fine scale. This heterogeneous nature of the structure is directly responsible for the unexpectedly low heat (and temperature) of crystallization observed in calorimetric measurements.

29Si and "A1 MAS-NMR were performed on NaOHactivated blast-furnace slag to better characterize the amorphous and poorly crystalline phases which occur in this system. The unreacted glass has a mainly dimeric silicate structure represented by a broad 29Si peak (FWHM = 15 ppm) centered at -74.5 ppm [el], with aluminum present exclusively in tetrahedral coordination. Upon reaction with 5M NaOH ( w / s = 0.4), three new *'Si peaks with widths of ca. 2 ppm are formed at -78.5 [el], -81.4 [Q'(lAl)], and -84.3 [Q']. Relative peak areas indicate a mostly dimeric silicate structure for the tobermorite-like C-S-H layers, with roughly a third of the bridging sites occupied by aluminum, and less than 10% by silicon. In addition to the tetrahedrally coordinated aluminum substituted in the C-S-H structure, 27AI MAS-NMR reveals the presence of aluminum in octahedral sites, which is attributed to the aluminate phase (C,M),AH,,. *'Si results indicate rapid initial consumption of the glass, with roughly a third of the glass reacting within the first day and another third consumed over the following 27 days.

A 19‐year‐old man with Philadelphia‐positive chronic myelogenous leukemia treated with interferon‐alpha (IFN‐alpha) therapy for 45 months had systemic lupus erythematosus disease features: malar rash, migratory arthralgias, elevated antinuclear antibodies, elevated antinative DNA, hypocomplementemia, lymphopenia, and proteinuria. After discontinuation of the IFN and initiation of corticosteroids, there was gradual recovery of symptoms, a decline in antinative DNA and antinuclear antibodies to normal levels, and a decrease in proteinuria. The potential association between IFN therapy and the development of systemic lupus erythematosus, and the role of IFN in other autoimmune diseases, is discussed.