Spatial sensitivity

Sahoo D, Narayanaswami V, Kay CM, Ryan RO (2000) Pyrene excimer fluorescence a spatially sensitive probe to monitor lipid-induced helical rearrangement of apolipophorin III. Biochemistry 39 6594-6601... 

Several other detections of substances at the cellular level were published in the mid-1990s, including NO and glucose. All these methods depend upon the good response time and spatial sensitivity made possible by the use of ultramicroelectrodes. 

Spectrograph An optical instrument equipped with a dispersing element, such as a grating or a prism, that allows a range of wavelengths to strike a spatially sensitive detector such as a diode array, charge coupled device, or photographic plate. 

Single electrodes also provide the basis for scanning electrochemical microscopy (SECM, Chapter 16). Groups of microelectrodes can be used in various interesting ways to provide a spatially sensitive characterization of a system. 

Halls, J.N. (2002) A spatial sensitivity analysis of land use characteristics and phosphorus levels in small tidal creek estuaries of North Carolina, USA. Journal of Coastal Research Special Issue 35, 340-351. 

Diffractive spectroelectrochemistry is a technique which is very much in its infancy, but it is clear that it has the potential to improve on the performance of previous methods. The low sensitivity of previous spectroelectrochemical methods limited their applicability to strong chromophores with millimolar concentrations. In the diffractive approach, the path length is not constrained by the diffusion process, so the sensitivity is much higher, and dilute solutions of weak chromophores can be examined. A wide variety of both analytical and kinetic experiments are possible with diffractive spectroelectrochemistry with its potentially increased generality over previous methods. In addition, a spatially sensitive probe of the thin layer of solution near an electrode permits many new questions about mass transport and chemical reactions to be addressed. Diffractive spectroelectrochemistry should evolve into an excellent probe of the diffusion layer, a region of utmost importance to electrochemistry, but one which is exceedingly difficult to probe with conventional methods. 

Because NMR signals are weak, it may be desirable to use a pulse-sequence repetition time (Tr) much less than five times the longitudinal relaxation time (Tj) in order to maximize the SNR per unit acquisition time. The strong spatial dependence of the flip angle also causes the relaxation state of the nuclei to vary strongly with position. Figure 4 shows the spatial sensitivity of a surface coil for various TrS, demonstrating the imprecise boundary of the sensitive volume. 

The XPS technique is not usually spatially sensitive, sampling depth varies with electron kinetic energy (and material) and the spectra is complicated by secondary features like X-ray satellites. The surface charging in insulators shifts binding energy scale. Hydrogen and helium can not be detected with good sensitivity. 

Thomas D. C., Siddall-Allum J. N., Sutherland I. A., and Beard R. W., Correction of the non-uniform spatial sensitivity of electrical impedance tomography images. Physiol. Meas., vol. 15, pp. A147-A152, 1994. 

Canah, C., Heidcanen, A., Muhammad, H. B., Hoyum, P., Pettersen, F.-L, Hemmingsen, M.,. .. Emneus, J. (2015). Bioimpedance morritoring of 3D cell culturing - Complementary electrode configurations for errhanced spatial sensitivity. Biosensors bioelectronics, 63, 72-79. 

Spatial Sensitivity of Immobilized Gold Nanoparticles on Glass... 

Fig. 7 Normalized human contrast sensitivity (Data from Campbell and Robson [12]) and normalized optical transfer function with a pupil diameter of 2 mm (Data from Ijspeert et al. [13]). The decline in human spatial sensitivity is much steeper than the optical decline. Thus, spatial sensitivity is driven by neuronal processing capacities...

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