Amyloid Plaques Beyond Aβ: A Survey of the Diverse Modulators of Amyloid Aggregation

Aggregation of the amyloid-β (Aβ) peptide is strongly correlated with Alzheimer’s disease (AD). Recent research has improved our understanding of the kinetics of amyloid fibril assembly and revealed new details regarding different stages in plaque formation. Presently, interest is turning toward studying this process in a holistic context, focusing on cellular components which interact with the Aβ peptide at various junctures during aggregation, from monomer to cross-β amyloid fibrils. However, even in isolation, a multitude of factors including protein purity, pH, salt content, and agitation affect Aβ fibril formation and deposition, often producing complicated and conflicting results. The failure of numerous inhibitors in clinical trials for AD suggests that a detailed examination of the complex interactions that occur during plaque formation, including binding of carbohydrates, lipids, nucleic acids, and metal ions, is important for understanding the diversity of manifestations of the disease. Unraveling how a variety of key macromolecular modulators interact with the Aβ peptide and change its aggregation properties may provide opportunities for developing therapies. Since no protein acts in isolation, the interplay of these diverse molecules may differentiate disease onset, progression, and severity, and thus are worth careful consideration

Luminescence spectroscopy of high-energy 4f 11 levels of Er3+ in fluorides

The 4f11 energy levels of Er3+ in LiYF4 in the spectral region 39 000–65 000 cm-1 have been studied. The agreement between experimental energy levels, obtained from luminescence excitation spectra, and calculated energy levels is good. Luminescence originating from high-lying energy levels has been investigated. Emission from the states 4D1/2 (47 200 cm-1), 2F(2)7/2 (54 700 cm-1) and 2F(2)5/2 (63 300 cm-1) is observed. 2F(2)5/2 emission occurs for Er3+ in LaF3, where the 2F(2)5/2 level is situated just below the lowest 4f 10 5d state, but also for Er3+ in LiYF4, where it lies in between the two lowest 4f 10 5d states