Local tissue array

An X-ray tube rotates helically around the subject while an array of detectors opposite the tube measures the residual radiation that has passed through the body according to the density of local tissues to X-rays. Cross-sectional images are constructed using mathematical algorithms... 

There are many possible causes of chemical and nutrient variability in tree tissues (27,28) which result in a wide range of spatial arrays of suitable and unsuitable food for insects (29). Although large-scale spatial variation may influence insect host race formation and have interesting consequences for insect biogeography and host race formation (30), the scale of variation with which the individual insect deals most often is more local, on the individual tree or tissue basis. 

Progression arrays These types of arrays are used to analyze the role of protein(s) in cancer progression and consist of normal tissues from patients without cancer, normal tissue from patients with cancer, pre-invasive lesions and tumor (from local and metastatic sites). The addition of normal tissue from close to the tumor and those much further away from the tumor site might enable study of field effect . 

Another approach to matrix application is to robotically deposit small (pL to nL) droplets of matrix on discrete areas of the sample surface. When the droplets are deposited as arrays over the entire tissue surface, mass spectra can be acquired at each matrix spot and reconstructed into an image. In this case, potential analyte delocalization is limited to the area under the matrix spot, typically -100-250 pm with commercially available spotters (e.g., Portrait 630 by Labcyte [23], ChIP by Shimadzu, TM iD by LEAP Technologies). This approach is fundamentally a trade-off between spatial integrity and resolution, because what limits resolution in most cases is the diameter of the laser beam, which is typically much smaller than the diameter of the matrix spot (on the order of 30-50 pm). Samples prepared by spray-coating, either manually or robotically, may be imaged at the diameter of the laser beam, but may not have maintained analyte localization throughout the spray process. 

There are situations where, during the course of normal cellular development, holes appear in the CMT array. One such example is during the formation of bordered pits in secondary xylem vessel elements [61]. Pit fields also develop in the maturing cell walls of the maize root cortex and may be pre-figured by the occasional MT holes that are normally seen in these cells. However, it is too early to say whether intracellular changes in gibberellin levels are related to these particular intracellular morphogenetic events which, in the case of secondary xylem vessels, would be rather localized to only a fraction of the cells within the secondary xylem tissue as a whole. 

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