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951.
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 NdxRE1?xP5O14 (RE = La, Eu, Tb) for 0.01 ? x ?1. 相似文献
952.
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). 相似文献
953.
954.
955.
Heinz Huber 《Commentarii Mathematici Helvetici》1956,30(1):20-62
Ohne Zusammenfassung
Von der Eidgen?ssischen Technischen Hochschule in Zürich als Habilitationsschrift angenommen. 相似文献
956.
Manganese‐Catalyzed Carbonylative Annulations for Redox‐Neutral Late‐Stage Diversification 下载免费PDF全文
Dr. Yu‐Feng Liang Ralf Steinbock Annika Münch Prof. Dr. Dietmar Stalke Prof. Dr. Lutz Ackermann 《Angewandte Chemie (International ed. in English)》2018,57(19):5384-5388
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. 相似文献
957.
A General Strategy to Access Structural Information at Atomic Resolution in Polyglutamine Homorepeats 下载免费PDF全文
Dr. Annika Urbanek Dr. Anna Morató Dr. Frédéric Allemand Dr. Elise Delaforge Aurélie Fournet Dr. Matija Popovic Dr. Stephane Delbecq Dr. Nathalie Sibille Dr. Pau Bernadó 《Angewandte Chemie (International ed. in English)》2018,57(14):3598-3601
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). 相似文献
958.
Mulhauser F. Bailey J. M. Beer G. A. Beveridge J. L. Douglas J. L. Fujiwara M. C. Huber T. M. Jacot-Guillarmod R. Kammel P. Knowles P. E. Kim S. K. Kunselman A. R. Maier M. Markushin V. E. Marshall G. M. Martoff C. J. Mason G. R. Olin A. Petitjean C. Porcelli T. A. Zmeskal J. 《Hyperfine Interactions》1996,101(1):229-237
The knowledge of muon transfer from protium to tritium is essentially theoretical and the different theoretical values disagree partially. Using solid hydrogen-tritium targets, with different tritium concentrations, we obtained precise experimental results for the transfer rate to tritium and the ppµ molecular formation rate. The time spectra of neutrons and alpha particles produced after dtµ fusion are used to determine the transfer rate pt and the molecule formation rate ppµ. 相似文献
959.
We consider thermodynamicallyV-representable one-matrices, i. e., one-particle density matrices that are obtained by reducing the Gibbs grand canonical density matrix of a quantum mechanical many-particle system subject to a suitable external potential, and show them to obey an inequality lower bounding their eigenvalues in terms of those of the one-particle kinetic energy operator. The result imposes a severe constraint on the asymptotic behavior of the eigenvalues of any one-matrix to beV-representable. For noninteracting particles, the corresponding upper bound is also proven, implying that a one-matrix can be interactionlesslyV-representable for at most one temperature. We expect the upper bound to be valid more generally, as is illustrated by a model of coupled harmonic oscillators where theV-representable one-matrices can be explicitly calculated, and discuss its implications for certain aspects of density-matrix functional theory. 相似文献
960.