Parameters related to pore-space structure of the trabeculae in cancellous bone are difficult to determine quantitatively, but they can be important to characterize changes induced in bone by diseases such as osteoporosis. We present two nuclear magnetic resonance (NMR) methods to measure the internal porosity φtrab of the trabeculae, based on two different measurements of the fraction of intratrabecular and intertrabecular pore-space in animal femur samples. These procedures have been developed within the more general framework of the NMR studies for fluids in porous media. In the first method we use the ratio between the amount of collagen (solid-like) H1 and that of the fluids in the samples. In the second, which can be applied only on defatted and water saturated samples, we use the distributions of longitudinal relaxation times. The φtrab values obtained are constant for porosity φ of the samples over the range 40%–70%, with each method giving φtrab=(29±4)%, which is consistent with the only data available, the porosity of related cortical bone. The traditional parameter bone volume fraction is simply given by (1−φ)/(1−φtrab).

Different "average" nuclear magnetic resonance relaxation times for correlation with fluid-flow permeability and irreducible water saturation in water-saturated sandstones In 1 H NMR ͑nuclear magnetic resonance͒ relaxation measurements for a set of eight hardwood and softwood samples, each free induction decay ͑FID͒ is fitted by the sum of a "solid" signal of the form A exp͓−c͑t / T S ͒ 2 ͔͓1−g͑t / T S ͒ 2 + h͑t / T S ͒ 4 ͔ plus a "liquid" signal B exp͑−t / T 2-FID ͒. Distributions of longitudinal ͑T 1 ͒ relaxation times were computed separately for the solid and liquid components, giving also the solid/liquid 1 H ratio ␣. From measurements on the samples dried, seasoned, and hydrated, the moisture content ͑liquid/solid weight ratio͒ was found to be approximately 0.50/ ␣. For each of the "seasoned" samples ͑10%-13% moisture content͒ a single T 1 peak was found for the solid and two for the liquid, with the longer liquid T 1 close to that of the solid, but with some differences exceeding perceived experimental uncertainties. None of the solid or liquid-long T 1 's is much less than 20 ms, even though liquid-short times go as low as 0.35 ms, appearing to negate simple solid-to-liquid exchange on a millisecond time scale. Data for six of the samples ͑all except for two resin-containing pine species͒ can be formally fitted by a two-site exchange model, in which cases the solid-to-liquid exchange times are a few tens of milliseconds. For our set of wood samples, each of the above three T 1 values, and also the overall liquid geometric-mean and rate-average T 1 's, as well as the liquid long-T 1 fraction, for a seasoned hardwood is longer than the corresponding value for any softwood, suggesting that relaxation parameters may provide a useful ranking of seasoned woods.

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Magnetic Resonance Relaxation (MRR) and Magnetic Resonance Imaging (MRI) are powerful tools to obtain detailed information on the pore space structure that one is unlikely to obtain in other ways. These techniques are particularly suitable for Cultural Heritage materials, because they use water 1H nuclei as a probe. Interaction with water is one of the main causes of deterioration of materials. Porous structure in wood, for example, favours the penetration of water, which can carry polluting substances and promote mould growth. A particular case is waterlogged wood from underwater discoveries and moist sites; in fact, these finds are very fragile because of chemical, physical and biological decay from the long contact with the water. When wood artefacts are brought to the surface and directly dried in air, there is the collapse of the cellular structures, and wood loses its original form and dimensions and cannot be used for study and museum exhibits. In this work we have undertaken the study of some wood finds coming from Ercolano's harbour by MRR and MRI under different conditions, and we have obtained a characterization of pore space in wood and images of the spatial distribution of the confined water in the wood.

Proton nuclear magnetic resonance (NMR) relaxometry can give informations about hydrogel scaffold properties. As these properties can be modified with culture time and conditions according to scaffold biodegradability and new tissue biosynthesis, the aim of this research was to test the efficiency of this noninvasive NMR technique in the follow-up of 3D cultures for tissue engineering. The distributions of proton relaxation times T1 and T2 have been measured on cylindrical gel samples of different types of alginate, in the presence or absence of hyaluronate, in gels or bioconstructs with encapsulated chondrocytes cultured for 30 days in normal or reduced weight conditions. It was found that T2 increases with the mannuronate/guluronate ratio in alginate samples and with the presence of hyaluronate. The distributions of both T1 and T2 result wider for bioconstructs cultured in normal gravity than for those cultured in reduced weight conditions. Neither cell growing nor collagen production but only GAG neosynthesis have been demonstrated in our experimental conditions. In conclusion, T2 is sensitive to the gel properties (possibly to the rigidity of macromolecular components). The homogeneity of bioconstructs can be monitored by the distribution of T1 and T2. We propose that nonspatially resolved NMR relaxometry can efficiently be used in monitoring tissue development in a biodegradable scaffold for tissue engineering.