Signature patterns

Share your rainbow glasses or CD with a friend on your next night on the town. You ll find each type of light has its own signature pattern. How many different patterns are you able to observe ... 

These features are then passed on to machine learning algorithms to classify the signals. In particular, multifractal properties are a clear indicator of arrhythmia in ECG signals. The onset of deformity in the ECG signal has a signature pattern that can be used to predict the onset of a heart attack. Scinova proposes to exploit this feature of Rx as an early warning system for intensive care units. 

For the purpose of analyte identification, the response of the detector array to exposure to the analyte vapor must be recorded, and a unique pattern or chemical signature for each analyte must be extracted from the data. A good signature pattern highlights the characteristic features of the data that yield high differentiation between patterns and eliminates those features that provide little or no differentiation information. 

After preprocessing the data, the search begins to find the features in the data that show the largest differences between patterns. This process is very much dependent on the type of detectors in the detection system but may involve comparing the relative amplitudes of the different detectors in the array, the derivative of the response, or even mathematical transforms of the data to select which features show the most differentiation between the patterns of different analytes. For our examples described in Section 5.3., we chose to use 120-data point analyte signature patterns sampled from the entire shape of the signal from a detector array of four cantilevers with coatings described in Section 3.5. 

In Fig. 8 are shown the chemical signature patterns for five known analytes and one unknown analyte. The patterns were extracted from the response of an array of four coated microcantilevers to exposure to each analyte vapor. The four cantilever coatings... 

Fig. 8. Analyte chemical signature patterns. The inset at the top of the Figure shows the temporal response of one of the four cantilevers in the detector array. The responses for all four detectors were recorded simultaneously, and the signature pattern for each analyte was created by combining the four responses...

Tabibiazar R, Wagner RA, Ashley EA, King JY, Ferrara R, Spin JM, Sanan DA, Narasimhan B, Tibshirani R, Tsao PS, Efron B, Quertermous T (2005) Signature patterns of gene expression in mouse atherosclerosis and their correlation to human coronary disease. Physiol Genomics 22 213-226... 

PROSITE http //ww.expasy.oig/prosite Funct/signature patterns and profiles... 

For a jump mechanism, is also anisotropic. The anisotropy, measured with an inversion recovery experiment near the null-point, can provide a signature pattern for a particular mechanism. Figure 8.6 also shows an inversion recovery spectrum, obtained at 220°C and a simulation [88], Wittebort et al have described the theoretical calculation of anisotropy for a jump model [113,134]. For C-D bond orientations close to the PAS axes, Tj has a larger value and therefore these signals are inverted. This particular pattern is unique to the ring-flip mechanism and distinguishes it from other motions which might coincidently cause a spectrum of the same shape. 

Check your work) The peaks at 1.1 and 2.5 ppm on the previous page represent the signature pattern of an ethyl group. This pattern (a quartet worth 2H s and a triplet worth 3 H s) is so common it is worth memorizing. 

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