Problem severity profiles

Antibody microarrays are the most common target microarrays. Target microarrays consist of different proteins printed onto planar-solid surfaces (7,8). In general, these arrays have found several applications in clinical studies because they allow identification of specific protein profiles. One of the major drawbacks of antibody microarrays is the need for oriented immobilization of the capture reagent onto the surface in order to avoid steric hindrance with the specific proteins presented in the sample. Therefore, to solve this problem, several strategies have been described that implied that chemical groups promote orientation and avoid cross-linkers that can interact nonspecifically with the query protein. Another important disadvantage is the loss of activity of proteins upon immobilization (9—11). 

When counting cells, it is indeed not cells that are counted but their profiles, i.e., a part of a stained cell that is contained within a histological section [25]. Thus, in the worst case, a cell might be thicker than section thickness, and thus several profiles of the same cell can be detected in adjacent sections (Fig. 2a). A solution to this problem is the use of sections thicker than the estimated cell height. 

A.irbome Basic Chemical Contamination. A critical, and at-first pu22ling problem, was encountered during early manufacturing trials of CA resists. Sporadically, severely distorted resist profiles would be formed in positive-tone CA resists, displaying what seemed to be a cap on the upper surface of the resist image (Fig. 26). In severe cases this cap or T-top would appear as a kin or cmst over the entire wafer surface that prevented development of the pattern. The magnitude of the effect varied dramatically between laboratories and appeared to grow more severe as the time interval between exposure and post-exposure bake was increased. 

The single most severe drawback to reflectivity techniques in general is that the concentration profile in a specimen is not measured directly. Reflectivity is the optical transform of the concentration profile in the specimen. Since the reflectivity measured is an intensity of reflected neutrons, phase information is lost and one encounters the e-old inverse problem. However, the use of reflectivity with other techniques that place constraints on the concentration profiles circumvents this problem. 

If a sample of polycrystalline material is rotated during the sputtering process, the individual grains will be sputtered from multiple directions and nonuniform removal of material can be prevented. This technique has been successfully used in AES analysis to characterize several materials, including metal films. Figure 9 indicates the improvement in depth resolution obtained in an AES profile of five cycles of nickel and chromium layers on silicon. Each layer is about 50 nm thick, except for a thinner nickel layer at the surface, and the total structure thickness is about 0.5 pm. There can be a problem if the surface is rough and the analysis area is small (less than 0.1-pm diameter), as is typical for AES. In this case the area of interest can rotate on and off of a specific feature and the profile will be jagged. 

The fact that vibration profiles can be obtained for all machinery having rotating or moving elements allows vibration-based analysis techniques to be used for predictive maintenance. Vibration analysis is one of several predictive maintenance techniques used to monitor and analyze critical machines, equipment, and systems in a typical plant. However, as indicated before, the use of vibration analysis to monitor rotating machinery to detect budding problems and to head off catastrophic failure is the dominant predictive maintenance technique used with maintenance management programs. 

However, not all looseness generates this classic profile. For example, excessive bearing and gear clearances do not generate multiple harmonics. In these cases, the vibration profile contains unique frequencies that indicate looseness, but the profile varies depending on the nature and severity of the problem. 

The reversibility of dA alkylation by QM3 creates both problems and opportunities. For example, an accurate profile of products formed by initial exposure of DNA to QMs may not be easily determined since labile products such as the N1 adduct of dA would not persist through the typical procedures of enzyme digestion and analysis of the subsequent deoxynucleoside products by reverse phase HPLC. Thus, the full extent of DNA alkylation by QMs may be severely underestimated. 

Maximum water reuse can be identified from limiting water profiles. These identify the most contaminated water that is acceptable in an operation. A composite curve of the limiting water profiles can be used to target the minimum water flowrate. While this approach is adequate for simple problems, it has some severe limitations. A more mathematical approach using the optimization of a superstructure allows all of the complexities of multiple contaminants, constraints, enforced matches, capital and operating costs to be included. A review of this area has been given by Mann and Liu21. 

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