Linear concentration quenching of luminescence in rare earth laser materials

Assuming fast spatial energy diffusion among the donor ions, the rate equations are shown to yield the linear concentration dependence of the quenching rate observed in highly concentrated rare earth compounds, such as NdP₅O₁₄. This concentration dependence is not related to the particular form of the interionic interaction responsible for the quenching. We also supply new experimental data confirming the linear behavior in Nd_xRE_1?xP₅O₁₄ (RE = La, Eu, Tb) for 0.01 ? x ?1.     

Synthesis of benzopyran prostaglandins,potent stable prostacyclin analogs,via an intramolecular mitsunobu reaction

Short syntheses of the extremely potent benzopyran prostacyclin mimics 26 and 27 are described using a novel intramolecular Mitsunobu reaction (e.g. 20 → 22) in the key step. This mild cyclization method was also applied to the synthesis of some simple chromans and benzofurans (34 – 38).     

Über eine neue Klasse automorpher Funktionen und ein Gitterpunktproblem in der hyperbolischen Ebene. I.

Ohne Zusammenfassung Von der Eidgen?ssischen Technischen Hochschule in Zürich als Habilitationsschrift angenommen.     

Manganese‐Catalyzed Carbonylative Annulations for Redox‐Neutral Late‐Stage Diversification

An inexpensive, nontoxic manganese catalyst enabled unprecedented redox‐neutral carbonylative annulations under ambient pressure. The manganese catalyst outperformed all other typically used base and precious‐metal catalysts. The outstanding versatility of the manganese catalysis manifold was reflected by ample substrate scope, setting the stage for effective late‐stage manipulations under racemization‐free conditions of a wealth of marketed drugs and natural products, including alkaloids, amino acids, steroids, and carbohydrates.     

A General Strategy to Access Structural Information at Atomic Resolution in Polyglutamine Homorepeats

Homorepeat (HR) proteins are involved in key biological processes and multiple pathologies, however their high‐resolution characterization has been impaired due to their homotypic nature. To overcome this problem, we have developed a strategy to isotopically label individual glutamines within HRs by combining nonsense suppression and cell‐free expression. Our method has enabled the NMR investigation of huntingtin exon1 with a 16‐residue polyglutamine (poly‐Q) tract, and the results indicate the presence of an N‐terminal α‐helix at near neutral pH that vanishes towards the end of the HR. The generality of the strategy was demonstrated by introducing a labeled glutamine into a pathological version of huntingtin with 46 glutamines. This methodology paves the way to decipher the structural and dynamic perturbations induced by HR extensions in poly‐Q‐related diseases. Our approach can be extended to other amino acids to investigate biological processes involving proteins containing low‐complexity regions (LCRs).