The increasing demand of analytical information related to inorganic engineered nanomaterials requires the adaptation of existing techniques and methods, or the development of new ones.The challenge for the analytical sciences has been to consider the nanoparticles as a new sort of analytes, involving both chemical (composition, mass and number concentration) and physical information (e.g. size, shape, aggregation). Moreover, information about the species derived from the nanoparticles themselves and their transformations must also be supplied. Whereas techniques commonly used for nanoparticle characterization, such as light scattering techniques, show serious limitations when applied to complex samples, other well-established techniques, like electron microscopy and atomic spectrometry, can provide useful information in most cases. Furthermore, separation techniques, including flow field flow fractionation, capillary electrophoresis and hydrodynamic chromatography, are moving to the nano domain, mostly hyphenated to inductively coupled plasma mass spectrometry as element specific detector.Emerging techniques based on the detection of single nanoparticles by using ICP-MS, but also coulometry, are in their way to gain a position. Chemical sensors selective to nanoparticles are in their early stages, but they are very promising considering their portability and simplicity.Although the field is in continuous evolution, at this moment it is moving from proofs-of-2 concept in simple matrices to methods dealing with matrices of higher complexity and relevant analyte concentrations. To achieve this goal, sample preparation methods are essential to manage such complex situations. Apart from size fractionation methods, matrix digestion, extraction and concentration methods capable of preserving the nature of the nanoparticles are being developed. This review presents and discusses the state-of-the-art analytical techniques and sample preparation methods suitable for dealing with complex samples. Single-and multimethod approaches applied to solve the nanometrological challenges posed by a variety of stakeholders are also presented.

The upward movement of water due to transpiration stops when soil water potential ( s ) drops below leaf water potential ( L ). Under these circumstances, water can move in any direction in the plant-soil continuum through the passive conduits of roots and stems towards the lowest  s . This is generally termed as hydraulic redistribution (HR), but the positioning and orientation of the driving water potential gradient may vary. Any experimental method that can measure bi-directional and low flows in the sapwood of roots and stems will be suitable to detect HR. Using one approach for measuring sap flow (the heat field deformation technique, HFD) in several forest species and sites across Europe, we were able to provide evidence on different types of HR: vertical hydraulic redistribution (VHR), horizontal hydraulic redistribution (HHR), foliar uptake (FU) and tissue dehydration (TD). VHR is the vertical water movement through roots in response to water potential differences between deep and topsoil, either hydraulic lift or hydraulic descent. HHR is the lateral water movement through roots in response to horizontal water potential gradients, namely under localised irrigation. FU is the water movement from crown to soil through stems when the crown is wetted by foggy weather. TD is the downward movement of water in stems or roots from above-ground tree tissues to soil under prolonged drought or frost. Results from direct sap flow measurements indicated the vectoral and widespread nature of HR, a phenomenon of paramount importance for overall physiology and ecohydrology.

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Strains of a new species of rapidly growing, nonphotochromogenic mycobacteria, Mycobacterium mageritense, were isolated from human sputum. The growth characteristics, acid fastness, and mycolic acids of the isolates were consistent with those of Mycobacterium species. The isolates were identified as members of a new species by performing a biochemical analysis and DNA-DNA hybridization experiments, and by comparing the sequences of several conserved genes, such as the 16s rRNA, hsp65, and sod4 genes. A phylogenetic analysis in which 16s rRNA and sod4 sequences were used identified M. mageritense as a novel distinct species and placed M. mageritense between members of the Mycobacteriumfortuitm complex and the thermotolerant rapidly growing group. Our results demonstrate that the taxonomic value of sod4 sequence analysis in the genus Mycobacterium is similar to the well-established value of 16s rRNA sequence analysis.Mycobacteria are aerobic, nonmotile bacteria that are widespread in nature and range from soil-dwelling saprophytes to pathogens of humans and animals (10,36). In taxonomic studies of members of the Mycobacteriaceae workers have traditionally relied on biochemical and cultural characteristics (33, 34) together with analyses of fatty acid composition (8) to determine the identity of a new organism. The systematics of these organisms has been refined by techniques such as highperformance liquid chromatography (7), multilocus enzyme electrophoresis (21), DNA-DNA hybridization, and phylogenetic classification based on the evolutionary sequence diversity of one or more universally present genes (26). The most commonly used gene for phylogenetic studies has been the 16s rRNA gene; however, the inability of 16s rRNA gene data to distinguish some closely related species (1) has suggested that other conserved genes, such as hsp65 (31) and sodA (5, 38), should be used. The current general recommendations for descriptions of new mycobacterial species include the need for at least DNA-DNA hybridization, biochemical, and cultural studies to show significant differences from previously described clusters of organisms (15).Mycobacterial strains that could not be identified by conventional identification procedures were isolated from human sputum specimens. Colonization of the respiratory tract was not associated with disease in all cases. In this paper we describe the results of a taxonomic study of these strains and propose a new species, Mycobacterium mageritense. MATERIALS AND METHODSBacterial strains. Five new strains were studied. Two of these strains (strains 93gT [T = type strain] and 1336) were received in 1987 from the Hospital Cantoblanco in Madrid, Spain; two (strains 1635 and 1636) were received from the same hospital in 1989: and one (strain 1470) was received in 1987 from the Hospital Santa Marina in Pais Vasco, Spain. All of the strains were recovered from sputum specimens from different patients. In addition, we studied the Characterization of strains. Standard methods were used to isolate mycobacte...