The 2D satellite transition magic angle spinning (STMAS) experiment generates efficiently high-resolution isotropic NMR spectra of half-integer quadrupolar nuclei. The experiment involves excitation and coherence transfer of satellite transitions into the central transition. It requires efficient refocusing of satellite transitions and sample spinning at a very accurate magic angle to cancel the first-order quadrupolar interaction effect. A review of all parameters relevant to optimizing the STMAS experiment is presented, including pulse sequence calibration, regulating spinning speed, magic angle adjustment, optimization of satellite transition excitation, and coherence transfer for both I = 3/2 and I > or =5/2 nuclei.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1006/jmre.2002.2548 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Nematic versus Kekulé Phases in Twisted Bilayer Graphene under Hydrostatic Pressure.
Phys Rev Lett
December 2024
Instituto de Ciencia de Materiales de Madrid, CSIC, E-28049 Madrid, Spain.
We address the precise determination of the phase diagram of magic angle twisted bilayer graphene under hydrostatic pressure within a self-consistent Hartree-Fock method in real space, including all the remote bands of the system. We further present a novel algorithm that maps the full real-space density matrix to a 4×4 density matrix based on a SU(4) symmetry of sublattice and valley degrees of freedom. We find a quantum critical point between a nematic and a Kekulé phase, and show also that our microscopic approach displays a strong particle-hole asymmetry in the weak coupling regime.
View Article and Find Full Text PDFThe recent surge of interest in moiré photonics arises from the possibility of exploring many groundbreaking physical phenomena in photonics. These phenomena include photonic topological states and magic-angle lasing, which offer an attractive platform for manipulating the flow and confinement of light from remarkably simple device geometries. In this work, we fabricate a series of metallic moiré superlattices supporting moiré plasmon polaritons and explore the moiré-potential induced plasmonic resonances.
View Article and Find Full Text PDFMolecular miscibility of ASD blend components: an evaluation of (the added value of) solid state NMR spectroscopy and relaxometry.
J Pharm Sci
January 2025
Drug Delivery and Disposition, KU Leuven, Department of Pharmaceutical and Pharmacological Sciences, Campus Gasthuisberg ON2, Herestraat 49 b921, 3000 Leuven, Belgium. Electronic address:
In order to evaluate the stability of an amorphous solid dispersion (ASD) it is crucial to be able to accurately determine whether the ASD components are homogeneously mixed or not. Several solid-state analysis techniques are at the disposal of the formulation scientist, such as for example modulated differential scanning calorimetry (mDSC) and solid-state nuclear magnetic resonance spectroscopy (ssNMR). ssNMR is a robust, versatile, and accurate analysis technique with a large number of application possibilities.
View Article and Find Full Text PDFMisfolding and aggregation of proteins into amyloidogenic assemblies are key features of several metabolic and neurodegenerative diseases. Human insulin has long been known to form amyloid fibrils under various conditions, which affects its bioavailability and function. Clinically, insulin aggregation at recurrent injection sites poses a challenge for diabetic patients who rely on insulin therapy.
View Article and Find Full Text PDFDeciphering the Topology of Sitagliptin Using an Integrated Approach.
ACS Omega
January 2025
Science Division, New York University Abu Dhabi, P.O. Box 129188, Abu Dhabi, United Arab Emirates.
Determining the structure of sitagliptin is crucial for ensuring its effectiveness and safety as a DPP-4 inhibitor used to treat type 2 diabetes. Accurate structure determination is vital for both drug development and maintaining quality control in manufacturing. This study integrates the advanced techniques of solid-state nuclear magnetic resonance (NMR) spectroscopy, three-dimensional (3D) electron diffraction, and density functional theory (DFT) calculations to investigate the structural intricacies of sitagliptin.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!