Structural tissues like tendon are subjected to repeated tensile strains and excessive strains cause irreversible changes to the tissue. Large strains affect the molecular structure and organization of the extracellular matrix, and these are the parameters that drive cell behavior, including tissue repair. Here we describe a method to perform solid-state NMR spectroscopy on strained tissue samples under magic-angle spinning to achieve high-resolution NMR spectra while maintaining the tissue's native hydration state. The changes observed in the NMR spectra are interpreted using quantum mechanics molecular mechanics (QM/MM) chemical shift calculations on strained collagen triple-helix structures and consideration of changes in the distribution of molecular orientations between strained and relaxed mechanical states. We demonstrate that our tissue strain method in combination with spectral simulations can detect changes in collagen organization between tendons loaded to plastic deformation and subsequent structural relaxation in the unloaded state.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1021/jacs.4c13930 | DOI Listing |
Inorg Chem
March 2025
Institut des Molécules et Matériaux du Mans (IMMM)─UMR 6283 CNRS, Le Mans Université, Avenue Olivier Messiaen, 72085 Le Mans Cedex 9, France.
Describing the crystal structure of disordered materials with mixed-occupancy crystallographic sites is essential for understanding their physicochemical properties and designing new materials tuned to their targeted functionalities. Here, we investigate the structure of RbMOF (M = Nb, Ta) pyrochlore-type oxyfluorides using a multimodal approach that combines experimental and computational techniques. Rietveld structural refinement of powder X-ray powder diffraction (PXRD) data confirmed that these oxyfluorides are isostructural, and their average crystal structure is disordered.
View Article and Find Full Text PDFChem Soc Rev
March 2025
Department of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
Whilst bis(trimethylsilyl)amide has been used extensively as a ligand across the periodic table, the chemistry of its heavier group 15 congeners is relatively underdeveloped. However, bis(trimethylsilyl)phosphide coordination chemistry has provided unique structural motifs and has also shown potential applications in catalysis, materials science, and bioinorganic chemistry. This review, which marks 55 years since the first report of a bis(trimethylsilyl)phosphide complex, provides a comprehensive overview of the synthesis, characterisation and reactivity of structurally authenticated s-, p-, d- and f-block metal complexes of this ligand, focusing on salient single crystal XRD and NMR spectroscopic data.
View Article and Find Full Text PDFJ Magn Reson
March 2025
Department of Chemistry, Dalhousie University, Halifax NS B3H 4R2, Canada.
For computing the magnetic shielding in solids, density functional theory as implemented in a plane wave basis has proven to be a reasonably accurate and efficient framework, at least for lighter atoms through the third row of the periodic table. In materials with heavier atoms, terms not usually included in the electronic Hamiltonian can become significant, limiting accuracy. Here we derive and implement the zeroth-order regular approximation (ZORA) relativistic terms in the presence of both external magnetic fields and internal nuclear magnetic dipoles, to derive the ZORA-corrected magnetic shielding in the context of periodic boundary conditions and a plane wave basis.
View Article and Find Full Text PDFBiochemistry
March 2025
Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, Massachusetts 02139, United States.
Aggregation of the tau protein into cross-β amyloid fibrils is a hallmark of Alzheimer's disease (AD) and many other neurodegenerative disorders. Developing small molecules that bind these tau fibrils is important for the diagnosis and treatment of tauopathies. Here, we report the binding sites of a positron emission tomography (PET) ligand, PI-2620, to a recombinant tau construct that adopts the C-shaped AD fold.
View Article and Find Full Text PDFRSC Adv
March 2025
REZEL Catalysts Corp. Shanghai 201313 China +86-21-38280081.
0.5%Au supported on γ-AlOOH and γ-AlO was used for low temperature oxidation of CO and aromatic alcohols. Various characterization techniques, including X-ray diffraction, N adsorption, FT-IR spectroscopy, XPS, TEM, CO-TPD and solid-state MAS NMR, were employed to characterize these catalysts.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!