The present review highlights the recent applications of mid-infrared spectroscopy and in particular of diffuse reflectance spectroscopy (DRIFT) and attenuated total reflectance (ATR) and processing methods (e.g., deconvolution, derivative and chemometrics) to rapidly provide valuable information on soil composition and organic geochemistry. Research has demonstrated that both DRIFT and ATR techniques can be considered useful tools for the analysis of a large number of soil samples, giving not only typical spectral patterns but permitting an accurate prediction of quantitative parameters such as, e.g., total carbon, total nitrogen, C/N ratio, lignin, dissolved OC, carbonyl-C, aromatic-C, O-alkyl-C, and alkyl-C contents. Based on literature results, infrared spectroscopy can be recognized as one of the most promising analytical techniques for investigating soil science.

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Raman and infrared spectra of liquid dimethylsulphoxide (DMSO) and DMSO-water mixtures in a wide range of concentrations are reported and discussed. It is found that changes in the vibrational spectra can be related to a gradual insertion of water molecules in the cluster structure of liquid DMSO. In the more dilute aqueous solutions a gradual lowering of the vsz0 stretching frequency is observed and this can be related to the cooperative character of DMSO-water interactions. The interpretation of the spectra is in agreement with the capacity of DMSO for 'breaking' the structure of water in the more concentrated aqueous solutions and 'enhancing' it in very dilute solutions. INTRODUCTIONThe structure of liquid water and aqueous solutions of polar and apolar solutes has been the subject of many investi ations,'"-' including a number from this laboratory.The current models of water structure can be broadly divided into several categories: the 'continuum which considers water to be completely hydrogen bonded, but having a continuous distribution of molecular geometries and hydrogen bond strengths; the 'cluster m~d e l ' , '~-'~ in which water is regarded as being a mixture of clusters of H 2 0 molecules, each molecule being linked to four others, in equilibrium with single H2O molecules included in the clusters. More recent 'mixture m o d e l~' '~-'~ consider liquid water to be a mixture of a small numbers of distinct species of molecular aggregates, with a different number of hydrogen bonds for each molecule. Experimental evidence for the mixture models arises from both spectroscopic data (IR2' and Raman2*) and from radial diffusion function (RDF) data.22In considering the structure of aqueous solutions, a clear distinction must be made between dilute and concentrated solutions. Dilute aqueous solutions can be suitably treated by dividing solutes into 'structuremaking' or 'structure-breakin ' on the basis of their effects on solvent structures. ","'Structure-making' solutes cause an 'enhancement' or a 'rigidification' of water structure, whereas 'structure-breaking' solutes cause a disruption of solvent structures. This model is not applicable to concentrated aqueous solutions, where the concept of 'structure of water' becomes meaningless. We have considered this point in a recent paper.6 On the basis of earlier work on the structure of concentrated aqueous solutions of strong inorganic acids, bases and their salts, and on the cooperative character of hydrogen bond^,^ we have proposed a structural model for concentrated aqueous solutions of electrolytes as a function of the ionic electrostatic field of the solute. 2-FThe interest in structural characterization of aqueous solutions of dimethylsulphoxide (DMSO) arises not only because of its extensive use as an industrial solvent, but also because of its unusual chemi~o-physical~~ and biological25 properties.The radial diffusion function (RDF) obtained from X-ray diffraction26 and neutron inelastic scattering (NIS)26 studies of aqueous solutions of DMSO showed an 'enh...

The chemical conjugation of bisphosphonates (BPs), specifically alendronate, to hydroxyapatite could be an effective means to impart to it fine-tuned bioactivity. Horse heart myoglobin (Mb), a well-characterized protein, has been adsorbed onto biomimetic hydroxyapatite nanocrystals (nHA) and onto the nHA/alendronate conjugate powdered samples. The obtained materials have potential use in bone implantation and as prospective drug-delivery devices. The kinetic absorption of Mb onto nHA is dramatically affected by its functionalization with alendronate. The covering of the nHA surface by alendronate inhibits the adsorption of myoglobin. The adsorption mechanisms of the protein were studied by spectroscopic techniques (UV-vis and surface-enhanced Raman spectroscopy). The results indicate that the protein changes conformation upon adsorption on the inorganic substrate. In particular, the interaction with nHA alters the coordination state of the iron in the heme through the formation of a hexacoordinated low-spin Mb heme, possibly involving the distal histidine. Instead, the covering of the nHA surface by alendronate does not adsorb the protein but preserves the coordination state of the heme moiety. This study could be of significance either in the field of biomaterials science, in particular, to fine tune a bone-specific drug delivery device and to test nHA as a new support for heterogeneous catalysis, improving the understating of enzyme immobilization.