CRANFIELD UNIVERSITY Eleni Anthippi Chatzimichali ...

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1.1.2 The ‘omics’ disciplines Ever since the first automated DNA sequencing machine (See Figure 1-1), there has been a tremendous increase in the development of high-throughput platforms leading to the accumulation of vast amounts of highly heterogeneous biological data. These large-scale sets of data and biological information have inspired several novel fundamental concepts – namely, the ‘omics’ disciplines. These disciplines propel systems-level understanding, having as a chief aim the simultaneous quantification and identification of the building blocks of a biological system such as genes, proteins or metabolites, as well as the investigation of the interactions among them such as protein-protein. Three of the most important ‘omics’ sources are genomics, proteomics and metabolomics. The term genomics was established to denote the analysis of the entire genome – the complete genetic sequence – of an organism. In all cellular organisms, the genome is composed of deoxyribonucleic acid (DNA). Proteomics can be defined as the scientific field that focuses on the study of the proteome. The proteome is the entire collection of proteins that are expressed by a particular genome. However, even though the genome of a cellular organism is static – it alters only when mutations occur – the proteome changes constantly as a result of internal and external factors. Metabolomics is likewise defined as the comprehensive profiling of the metabolome. The metabolome consists of all the biochemicals and metabolites produced by a cellular organism. Metabolites are substances either required for or produced by biochemical reactions of metabolism that occur within the cells of an organism. Metabolomics allows scientists to study and compare the relationships between an organism’s genotype and phenotype, as well as the relationships between the genotype and the environment (Hassani et al., 2010). This project will be focusing on the field of metabolomics, and in particular the study of metabolites responsible for meat spoilage. The analytical techniques that will be used in this project are briefly presented as follows. 3
1.1.2.1 Fourier Transform Infrared (FTIR) Spectroscopy Fourier Transform Infrared (FTIR) spectroscopy is a very rapid (running over a few seconds) non-destructive analytical technique used for high-throughput biochemical fingerprinting (Ellis and Goodacre, 2001). In FTIR, a particular bond absorbs light or electromagnetic radiation by an infrared beam at a specific wavelength (Ellis et al., 2004). As a result of FTIR analysis, an infrared absorbance spectrum can be extracted, which may be used as a biochemical or metabolic “fingerprint” of the samples. However, FTIR spectra tend to be quite complex featuring hundreds or thousands of variables, thus necessitating the use of statistical methods for their analysis. FTIR in combination with multivariate statistical techniques has proven to be a very fast and accurate method for food-based analyses and bacterial detection (Nicolaou et al., 2011). Figure 1-2 Electromagnetic spectrum The figure has been extracted from Sattlecker (2011). 4
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Page 3 and 4: ABSTRACT Muscle foods such as meat,
Page 5 and 6: TABLE OF CONTENTS ABSTRACT ........
Page 7 and 8: 6.2.4 The iWebPlots package .......
Page 9 and 10: Figure 3-12 Speedup produced by the
Page 11 and 12: Figure 6-9 Sweave example for the d
Page 13 and 14: TABLE OF EQUATIONS Equation 1 Mean-
Page 15 and 16: RMSE RMSECV SSE SVD SVMs SYMBIOSIS-
Page 17: Figure 1-1 Evolution from molecular
Page 21 and 22: 1.1.3 Microbial Spoilage in Meat Sy
Page 23 and 24: The multivariate techniques applied
Page 25 and 26: 1.4 Multivariate Analysis: Unsuperv
Page 27 and 28: 1.4.2 Cluster Analysis Cluster anal
Page 29 and 30: 1.5 Multivariate Analysis: Supervis
Page 31 and 32: In any linearly separable binary da
Page 33 and 34: Where ( ) are the Lagrange multipli
Page 35 and 36: Every kernel is characterised by a
Page 37 and 38: The “one-against-all” approach
Page 39 and 40: Furthermore, metrics such as the bi
Page 41 and 42: 1.6.3 Leave-One-Out Cross-Validatio
Page 43 and 44: In such cases, the model becomes qu
Page 45 and 46: 1.8 Aims and objectives The overall
Page 47 and 48: 2 Development of the multivariate a
Page 49 and 50: Sensory panel scores were of the hi
Page 51 and 52: DF (Hz) 2.2.1.5 Electronic Nose (e-
Page 53 and 54: Figure 2-3 Data intersection The fi
Page 55 and 56: 3. Validation Techniques In the cas
Page 57 and 58: Figure 2-4 The process of construct
Page 59 and 60: 2.3 Results and Discussion 2.3.1 Pr
Page 61 and 62: (b) HPLC data (c) e-nose data Figur
Page 63 and 64: In the case of FTIR, linear classif
Page 65 and 66: 2.3.2.2 Class Prediction Accuracies
Page 67 and 68: Figure 2-7 Class prediction rates o
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The topology of the three-dimension
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Figure 2-9 Three-dimensional error
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Furthermore, a thorough comparison
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In the master/slave architecture, a
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precision of the classification acc
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Figure 3-3 The steps of the Nelder-
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3.3 Results and Discussion 3.3.1 Li
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3.3.2 Nonlinear Models In order to
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9) 10) 11) 12) 13) 14) 15) 16) Figu
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As an additional visual aid, these
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a) Number of iterations b) Number o
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Figure 3-10 Comparison of the execu
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Figure 3-12 Speedup produced by the
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4 Integration of Heterogeneous Data
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4.2.2 Procrustes Analysis Procruste
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symmetric method since the ordering
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Figure 4-3 Steps of CPCA for the da
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4.2.5 Data Integration and Analysis
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Figure 4-4 Data integration workflo
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a) GPA b) CPCA Figure 4-6 The conse
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accuracies as the linear models; po
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Figure 4-8 Classification Results f
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Similar to FTIR, the PLS-DA ensembl
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Figure 4-9 Class prediction rates o
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4.3.3 Permutation Tests Even though
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Even though the interpretation of t
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Figure 4-12 Distribution plots of t
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RBF SVMs Datasets Original %CC Mean
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Figure 4-14 Boxplots representing t
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5 Application of the multivariate a
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Figure 5-1 Mean FTIR spectra for ca
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5.2.2.2 Fourier Transform Infrared
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5.2.2.4 Data Overview For each expe
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5.2.3.3 High Throughput Liquid Chro
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Figure 5-5 displays the PCA scores
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(a) GPA (b) CPCA Figure 5-6 The con
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observation confirms that indeed CP
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Figure 5-8 Class prediction rates o
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(a) RBF SVMs (b) PLS-DA Figure 5-9
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Figure 5-12 Execution times of the
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(a) FTIR data (b) Raman data Figure
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The classification results for the
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Figure 5-16 Class prediction rates
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(a) RBF SVMs (b) PLS-DA Figure 5-17
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Figure 5-20 Execution times of the
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(a) FTIR data (b) HPLC data 148
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(a) GPA (b) CPCA Figure 5-22 The co
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The classification results of the f
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Figure 5-24 Classification Results
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Figure 5-25 Class prediction rates
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The permutation results for the dat
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Figure 5-28 Distribution plots of t
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Figure 5-30 Boxplots representing t
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5.4 Comparison of the individual ca
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Figure 5-32 Investigating the commo
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6 Development of improved visualisa
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6.2.2 Generating static graphs As d
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Figure 6-2 Construction process of
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6.2.2.2 Generating dynamic reports
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activity, while simultaneously the
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or disappeared (Wang et al., 2008).
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ectangles, circles and/or irregular
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In addition to the static figures g
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c) graphics package d) ggplot2 pack
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In addition to aesthetics, faceting
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Datasets FTIR HPLC e-nose PLS-DA (L
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Figure 6-10 Interactive dendrogram
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6.4 Conclusion The work reported in
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large number of individual models i
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The generated suite of tools, as pr
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In addition, the difficulty to corr
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REFERENCES Almeida, J. A. S., Barbo
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Processing., Proceedings of the 12t
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Clarke, B., Fokoué, E. and Zhang,
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spectroscopy and machine learning",
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Gower, J. C. (1975), "Generalized p
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Jardon, M. (2006), Systems Biology:
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Nicolaou, N., Xu, Y. and Goodacre,
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Shah, A. A., Barthel, D., Lukasiak,
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Vera, G., Jansen, R. and Suppi, R.
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Xu, Y. and Goodacre, R. (2012), "Mu
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