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Sample A: Cover Page of Thesis, Project, or Dissertation Proposal

Sample A: Cover Page of Thesis, Project, or Dissertation Proposal

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interpretation to cover the remaining aspects [45-49]. Thus, some Microarray platf<strong>or</strong>ms<br />

implement multiple probes per target assessment in <strong>or</strong>der to improve the specificity <strong>of</strong> transcript<br />

recognition [8, 12]. In this respect, standard ELISAs are m<strong>or</strong>e akin to the single-probe-per-gene<br />

Microarrays, since ELISAs assay one specific epitope <strong>of</strong> a protein which is then taken to be<br />

representative <strong>of</strong> the protein in its entirety. However, ELISAs have been modified to compare<br />

abn<strong>or</strong>malities in protein sub-units [50], similar to Microarray exons studies, and the lessons <strong>of</strong> the<br />

suite <strong>of</strong> controls developed f<strong>or</strong> such assays should be considered by the Microarray standards<br />

groups as a conceptual guideline f<strong>or</strong> improved platf<strong>or</strong>ms.<br />

Background Contributions<br />

Background contributions to the signal are usually derived at the same time that individual spots<br />

are identified and extracted, and alg<strong>or</strong>ithms f<strong>or</strong> inc<strong>or</strong>p<strong>or</strong>ating the values are <strong>of</strong>ten inc<strong>or</strong>p<strong>or</strong>ated<br />

into the image analysis packages that are optimized f<strong>or</strong> the output <strong>of</strong> a particular scanner [51].<br />

Common adjustments include subtracting the immediately adjacent flu<strong>or</strong>escence surrounding<br />

individual spots [52] and/<strong>or</strong> a global adjustment <strong>of</strong> selected background regions to blocks <strong>of</strong> spots<br />

[52]. Such adjustments assume that any intensity is meaningful: they do not identify the minimal<br />

signal that is meaningful as a target response. The best remedy f<strong>or</strong> the uncertainty in the noise<br />

level would be the inc<strong>or</strong>p<strong>or</strong>ation <strong>of</strong> a quantifiable nucleic standard(s) on every array, <strong>or</strong> a<br />

calibration standard [7]. Background is contributed from both specific and non-specific sources,<br />

and can be truly random (noise, such as from scattered light in the scanner) <strong>or</strong> systematic (err<strong>or</strong>,<br />

such as the effect <strong>of</strong> SNPs in the sample population) in its contributions to the signal. These<br />

effects are dissected in m<strong>or</strong>e detail below.<br />

1) Specificity. Probe specificity can be estimated f<strong>or</strong> each set <strong>of</strong> complementary and<br />

near-complementary sequences under the prevailing reaction conditions using<br />

10

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