Comprehensive characterization of waterlogged archaeological wood by NMR relaxometry, diffusometry, micro-imaging and cryoporometry.

Chemical, physical, and biological decay may partially or totally hide the historical and technological information carried by waterlogged wood. Investigation of the above-mentioned decay processes is essential to assess the wood preservation state, and it is important to find new methods for the consolidation and safeguarding of wooden archaeological heritage. A conventional method for assessing the wood preservation state is light microscopy.

Ultrafast - NMR for Correlating Different Motional Regimes of Molecules.

Nuclear magnetic resonance (NMR) relaxation times provide detailed information about molecular motions and local chemical environments. Longitudinal relaxation time is most often sensitive to relatively fast, nano- to picosecond ranges of molecular motion. Rotating frame relaxation time reflects a much slower, micro- to millisecond range of motion, and the motional regime can be tuned by changing spin-lock field strength.

Impact of NHOH treatment on the ion exchange and pore characteristics of a metakaolin-based geopolymer.

We investigated the viability and influence of NHOH post-synthetic treatment on the pore characteristics of geopolymers. Geopolymers are a class of materials with amorphous aluminosilicate three-dimensional frameworks, regarded as amorphous analogues of zeolites. Similar to zeolites, when geopolymers are used in catalysis or adsorption applications, post-synthetic treatments such as ion exchange with NH salts (, NHCl and NHNO) and desilication (using strong bases such as NaOH) are necessary to introduce active sites and modify their pore structure, respectively.

Gas Uptake and Thermodynamics in Porous Liquids Elucidated by Xe NMR.

We exploited Xe NMR to investigate xenon gas uptake and dynamics in a porous liquid formed by dissolving porous organic cages in a cavity-excluded solvent. Quantitative Xe NMR shows that when the amount of xenon added to the sample is lower than the amount of cages present (subsaturation), the porous liquid absorbs almost all xenon atoms from the gas phase, with 30% of the cages occupied with a Xe atom. A simple two-site exchange model enables an estimate of the chemical shift of Xe in the cages, which is in good agreement with the value provided by first-principles modeling.

Melting of aqueous NaCl solutions in porous materials: shifted phase transition distribution (SIDI) approach for determining NMR cryoporometry pore size distributions.

Nuclear magnetic resonance cryoporometry (NMRC) and differential scanning calorimetry thermoporometry (DSC-TPM) are powerful methods for measuring mesopore size distributions. The methods are based on the fact that, according to the Gibbs-Thomson equation, the melting point depression of a liquid confined to a pore is inversely proportional to the pore size. However, aqueous salt solutions, which inherently exist in a broad range of biological porous materials as well as technological applications such as electrolytes, do not melt at a single temperature.

CAT on MOUSE: Control and automation of temperature for single-sided NMR instruments such as NMR-MOUSE.

Temperature-dependent experiments are a rapidly growing area of interest for low-field NMR. In this work, we present a new device for wide-range temperature control for single-sided NMR instruments. The presented device, called CAT, is simple to build, inexpensive, and easy to modify to accommodate different samples.

SPICY: a method for single scan rotating frame relaxometry.

is an NMR relaxation mode that is sensitive to low frequency molecular motions, making it an especially valuable tool in biomolecular research. Here, we introduce a new method, SPICY, for measuring relaxation times. In contrast to conventional experiments, in which the sequence is repeated many times to determine the time, the SPICY sequence allows determination of within a single scan, shortening the experiment time remarkably.

Sensitive, Efficient and Portable Analysis of Molecular Exchange Processes by Hyperpolarized Ultrafast NMR.

Molecular exchange processes are ubiquitous in nature. Here, we introduce a method to analyze exchange processes by using low-cost, portable, single-sided NMR instruments. The inherent magnetic field inhomogeneity of the single-sided instruments is exploited to achieve diffusion contrast of exchange sites and spatial encoding of 2D data.

The TAT Protein Transduction Domain as an Intra-Articular Drug Delivery Technology.

Objective: Intra-articular drug delivery holds great promise for the treatment of joint diseases such as osteoarthritis. The objective of this study was to evaluate the TAT peptide transduction domain (TAT-PTD) as a potential intra-articular drug delivery technology for synovial joints.

Design: Experiments examined the ability of TAT conjugates to associate with primary chondrocytes and alter cellular function both and .

Ultrafast diffusion exchange nuclear magnetic resonance.

The exchange of molecules between different physical or chemical environments due to diffusion or chemical transformations has a crucial role in a plethora of fundamental processes such as breathing, protein folding, chemical reactions and catalysis. Here, we introduce a method for a single-scan, ultrafast NMR analysis of molecular exchange based on the diffusion coefficient contrast. The method shortens the experiment time by one to four orders of magnitude.

Pulsed gradient stimulated echo (PGStE) NMR shows spatial dependence of fluid diffusion in human stage IV osteoarthritic cartilage.

Purpose: Human Osteoarthritic (OA) articular cartilage was investigated with spatially resolved pulsed gradient stimulated echo (PGStE) nuclear magnetic resonance (NMR) using strong gradients. In this study, the diffusivity of fluid and biopolymer was characterized as a function of depth within human OA cartilage cores.

Methods: One dimensional (1D) spatially resolved diffusion profiles were measured for human OA cartilage using a standard pulsed gradient stimulated echo (PGStE) sequence with the addition of a read imaging gradient.

Quantifying NMR relaxation correlation and exchange in articular cartilage with time domain analysis.

Measured nuclear magnetic resonance (NMR) transverse relaxation data in articular cartilage has been shown to be multi-exponential and correlated to the health of the tissue. The observed relaxation rates are dependent on experimental parameters such as solvent, data acquisition methods, data analysis methods, and alignment to the magnetic field. In this study, we show that diffusive exchange occurs in porcine articular cartilage and impacts the observed relaxation rates in T-T correlation experiments.