Adaptive contrast enhancement

Image analysis is an important aspect of many areas of science and engineering, and imaging will play an important role in characterizing self-assembled structures as well as in on-line process control. Development of effective noise identification and suppression, contrast enhancements, visualization, pattern recognition, and correlation algorithms should be co-opted where possible and adapted to the analysis of self-assembled structures. 

Differential expression of multiple copies of psbA encoding two forms of D1 may be related to adaptation of Synechococcus to different light environments. At low light, enhanced expression of psbAI results in an increased ratio of form I to form II in the thylakoid. In contrast, enhanced expression of both psbAII and psbAIII at high light gives rise to an increased ratio of form II to form I in the membrane. The functional difference between the two forms remains uiknown. 

Twellmann T, Lichte O, Nattkemper TW et al (2005) An adaptive tissue characterization network for model-free visualization of dynamic contrast-enhanced magnetic resonance image data. IEEE Trans Med Imaging 24 1256-1266... 

Electronic contrast enhancement systems can process the image of a normal black-and-white or color TV camera or a digital camera that has been adapted for use with the microscope. 

Figure 29 CT (top) and MR (bottom) images of contrast enhancement from dual-mode liposomes in a New Zealand White rabbit over time. White arrows indicate aorta (A), heart (H), carotid artery (C), spleen (S), and kidney (K). (Adapted from Ref. 93. Springer, 2007.)...

MDCT with high-resolution CTA is an excellent technique for the diagnosis, therapy, and follow-up of aortic pathologies. The examination protocol must be adapted to the clinical question in order to avoid excessive radiation exposure. Modern techniques Hke modulation of the tube current along the x-, y-, and z-axes can routinely reduce radiation exposure. In specific cases, it can even be further reduced by the reduction of the tube voltage. Depending on the cHnical question, nonenhanced scans and venous contrast-enhanced phases can contribute important information for diagnosis. 

R. M. Rangayyan, L. Shen, Y. Shen, J. E. L. Desautels, H. Bryant, T. J. Terry, N. Horeczko and M. S. Rose, "Improvement of Sensitivity of Breast Cancer Diagnosis with Adaptive Neighborhood Contrast Enhancement of Mammograms," IEEE Trans Inf Technol Biomed., vol. 1, pp. 16I-I70, Sept. 1997. 

Antidepressant drugs, by contrast, require long-term administration for their therapeutic effects to become evident. Thus, it is clear that the acute actions of these drugs, which are most often to enhance synaptic levels of monoamines, are not sufficient in themselves to mediate their therapeutic effects. Neither is the effect of increased monoamines on postsynaptic second messenger systems, which occurs relatively quickly as well, adequate to account for the therapeutic actions of antidepressants. The most obvious explanation, then, is that molecular adaptations in response to chronic exposure to these drugs are what underlie their therapeutic effects. Consistent with this idea, several hypotheses as to the nature of the relevant molecular adaptations have been proposed. Two models focus on adaptations of the 5-HTia receptor. One theory proposes that desensitization of presynaptic somatodendritic 5-HTia autoreceptors is responsible for the therapeutic action... 

FIG. 1.12 Electron micrograph of two different types of particles that represent extreme variations from spherical particles (a) tobacco mosaic virus particles (Photograph courtesy of Carl Zeiss, Inc., New York) and (b) clay particles (sodium kaolinite) of mean diameter 0.2 fim (by matching circular fields). In both (a) and (b), contrast has been enhanced by shadow casting (see Section 1.6a.2a and Figure 1.21). (Adapted from M. D. Luh and R. A. Bader, J. Colloid Interface Sci. 33, 539(1970). 

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