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Brito JBG, Bucco GB, John DK, Ferrão MF, Ortiz RS, Mariotti KC, Anzanello MJ. Wavenumber selection based on Singular Value Decomposition for sample classification. Forensic Sci Int 2020; 309:110191. [PMID: 32092622 DOI: 10.1016/j.forsciint.2020.110191] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 01/30/2020] [Accepted: 02/07/2020] [Indexed: 11/29/2022]
Abstract
The dissemination of falsified medicines is a public health risk. Techniques such as attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy are commonly adopted for fraudulent drug detection. However, the spectrum generated by the ATR-FTIR typically results in hundreds of wavenumbers, reducing the performance of classification methods aimed at discriminating between authentic and falsified medicines. This article proposes a novel method for selecting a reduced size subset of wavenumbers that improves the classifier performance. The singular value decomposition SVD is used to generate a wavenumber importance index. An iterative process creates k-nearest neighbor (KNN) models by adding the wavenumbers in a decreasing order according to the importance index. Wavenumbers that increase classification accuracy are selected. When applied to Cialis® ATR-FTIR data, the proposed approach retained average 0.51% of the original wavenumbers with 100% accurate classifications; as for the Viagra® data set, the method yielded perfect classifications retaining average 0.17% of the original wavenumbers.
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Affiliation(s)
- João B G Brito
- Federal University of Rio Grande do Sul - Department of Industrial Engineering, Av. Osvaldo Aranha, 99 - 5° andar, Porto Alegre, RS, Brazil.
| | - Guilherme B Bucco
- Federal University of Rio Grande do Sul - School of Administration, Washington Luiz, 855, Porto Alegre, RS, Brazil.
| | - Danielle K John
- Federal University of Rio Grande do Sul - Department of Inorganic Chemistry, Chemistry Institute, Av. Bento Gonçalves, 9500, Porto Alegre, RS, Brazil.
| | - Marco F Ferrão
- Instituto Nacional de Ciência e Tecnologia - Bioanalítca (INCT - Bioanalítica), Cidade Universitária Zeferino Vaz, Campinas, SP, Brazil.
| | - Rafael S Ortiz
- Brazilian Federal Police - Technical and Scientifical Division, Av. Ipiranga, 1365, Porto Alegre, RS, Brazil; Instituto Nacional de Ciência e Tecnologia Forense (INCT Forense), Brazil.
| | - Kristiane C Mariotti
- Instituto Nacional de Ciência e Tecnologia Forense (INCT Forense), Brazil; Federal University of Rio Grande do Sul - Department of Pharmacy, Av. Ipiranga, 2752, Porto Alegre, RS, Brazil.
| | - Michel J Anzanello
- Federal University of Rio Grande do Sul - Department of Industrial Engineering, Av. Osvaldo Aranha, 99 - 5° andar, Porto Alegre, RS, Brazil.
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Soares F, Anzanello MJ, Fogliatto FS, Ortiz RS, Mariotti KC, Ferrão MF. Enhancing counterfeit and illicit medicines grouping via feature selection and X-ray fluorescence spectrometry. J Pharm Biomed Anal 2019; 174:198-205. [PMID: 31174131 DOI: 10.1016/j.jpba.2019.05.064] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 05/27/2019] [Accepted: 05/29/2019] [Indexed: 11/30/2022]
Abstract
In this paper, we propose a novel framework to select the most relevant X-Ray Fluorescence (XRF) energy values (i.e., features) to enhance the clustering (grouping) of counterfeit and illicit medical tablets. The framework is based on the integration of multidimensional scaling (MDS) and Procrustes analysis (PA) multivariate techniques. MDS provides a projection of the original data into a lower dimension, while PA finds a projection matrix from the original data. Such outputs give rise to a feature importance index that guides an iterative feature selection process; after each feature is inserted in the subset, an optimization procedure based on a greedy search method is carried out to maximize the clustering quality assessed through the Silhouette Index (SI). The inorganic chemical fingerprinting of 41 commercial samples (Viagra®, Cialis®, Lazar®, Libiden®, Maxfil®, Plenovit®, Potent 75®, Rigix®, V-50®, Vimax® and Pramil®) and 56 seized counterfeit samples (Viagra and Cialis) was used to validate the proposed framework. From the original 2048 data points in the full spectra, we identified a subset comprised of 41 energy values that substantially improved clustering quality; the obtained groups were assessed by visual inspection of the PCA plots.
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Affiliation(s)
- Felipe Soares
- Departamento de Engenharia de Produção e Transportes - Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Michel J Anzanello
- Departamento de Engenharia de Produção e Transportes - Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil; Instituto Nacional de Ciência e Tecnologia Forense (INCT Forense), Brazil.
| | - Flavio S Fogliatto
- Departamento de Engenharia de Produção e Transportes - Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Rafael S Ortiz
- Setor Técnico-Científico, Superintendência da Polícia Federal, Porto Alegre/RS, Porto Alegre, RS, Brazil; Instituto Nacional de Ciência e Tecnologia Forense (INCT Forense), Brazil
| | - Kristiane C Mariotti
- Instituto Nacional de Ciência e Tecnologia Forense (INCT Forense), Brazil; Departamento de Farmácia - Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Marco F Ferrão
- Programa de Pós-Graduação em Química, Instituto de Química - Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil; Instituto Nacional de Ciência e Tecnologia Forense (INCT Forense), Brazil
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Machado N, Oppolzer D, Ramos A, Ferreira L, Rosa EA, Rodrigues M, Domínguez-Perles R, Barros AI. Evaluating the freezing impact on the proximate composition of immature cowpea (Vigna unguiculata L.) pods: classical versus spectroscopic approaches. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2017; 97:4295-4305. [PMID: 28276078 DOI: 10.1002/jsfa.8305] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Revised: 02/10/2017] [Accepted: 03/05/2017] [Indexed: 06/06/2023]
Abstract
BACKGROUND Freezing represents a common conservation practice regarding vegetal foodstuffs. Since compositional features need to be monitored during storage, the development of rapid monitoring tools suitable for assessing nutritional characteristics arises as a pertinent issue. In this study, cowpea (Vigna unguiculata L.) pods, both fresh and after 6 and 9 months of freezing at -18 °C, were evaluated by high-performance liquid chromatography for their content of protein as well as of essential and nonessential amino acids, while their Fourier transform infrared spectra in the mid infrared (MIR) and near infrared (NIR) ranges were concomitantly registered to assess the feasibility of this approach for the traceability of these frozen matrices. RESULTS For the NIR interval, the application of the 1st derivative to the spectral data retrieved the best results, while for lower concentrations the application of the Savitzky-Golay algorithm was indispensable to achieve quantification models for the amino acids. MIR is also suitable for this purpose, though being unable to quantify amino acids with concentrations below 0.07 mmol g-1 dry weight, irrespective of the data treatment used. CONCLUSIONS The spectroscopic approach constitutes a methodology suitable for monitoring the impact of freezing on the nutritional properties of cowpea pods, allowing accurate quantification of the protein and amino acid contents, while NIR displayed better performance. © 2017 Society of Chemical Industry.
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Affiliation(s)
- Nelson Machado
- Centre for the Research and Technology of Agro-Environmental and Biological Sciences, University of Trás-os-Montes and Alto Douro (UTAD-CITAB), Vila Real, Portugal
| | - David Oppolzer
- Centre for the Research and Technology of Agro-Environmental and Biological Sciences, University of Trás-os-Montes and Alto Douro (UTAD-CITAB), Vila Real, Portugal
| | - Ana Ramos
- Centre for the Research and Technology of Agro-Environmental and Biological Sciences, University of Trás-os-Montes and Alto Douro (UTAD-CITAB), Vila Real, Portugal
| | - Luis Ferreira
- The Animal and Veterinary Research Centre, University of Trás-os-Montes and Alto Douro (UTAD-CECAV), Department of Veterinary Sciences, Vila Real, Portugal
| | - Eduardo As Rosa
- Centre for the Research and Technology of Agro-Environmental and Biological Sciences, University of Trás-os-Montes and Alto Douro (UTAD-CITAB), Vila Real, Portugal
| | - Miguel Rodrigues
- The Animal and Veterinary Research Centre, University of Trás-os-Montes and Alto Douro (UTAD-CECAV), Department of Veterinary Sciences, Vila Real, Portugal
| | - Raúl Domínguez-Perles
- Centre for the Research and Technology of Agro-Environmental and Biological Sciences, University of Trás-os-Montes and Alto Douro (UTAD-CITAB), Vila Real, Portugal
| | - Ana Irna Barros
- Centre for the Research and Technology of Agro-Environmental and Biological Sciences, University of Trás-os-Montes and Alto Douro (UTAD-CITAB), Vila Real, Portugal
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Machado N, Domínguez-Perles R, Ramos A, Rosa EA, Barros AI. Spectrophotometric versus NIR-MIR assessments of cowpea pods for discriminating the impact of freezing. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2017; 97:4285-4294. [PMID: 28182278 DOI: 10.1002/jsfa.8251] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Revised: 12/16/2016] [Accepted: 01/31/2017] [Indexed: 06/06/2023]
Abstract
BACKGROUND Freezing represents an important storage method for vegetal foodstuffs, such as cowpea pods, and thus the impact of this process on the chemical composition of these matrices arises as a prominent issue. In this sense, the phytochemical contents in frozen cowpea pods (i.e. at 6 and 9 months) have been compared with fresh cowpea pods material, with the samples being concomitantly assessed by Fourier-transform infrared spectroscopy (FTIR), both mid-infrared (MIR) and near infrared (NIR), aiming to evaluate the potential of these techniques as a rapid tool for the traceability of these matrices. RESULTS A decrease in phytochemical contents during freezing was observed, allowing the classification of samples according to the freezing period based on such variations. Also, MIR and NIR allowed discrimination of samples: the use of the first derivative demonstrated a better performance for this purpose, whereas the use of the normalized spectra gave the best correlations between the spectra and specific contents. In both cases, NIR displayed the best performance. CONCLUSION Freezing of cowpea pods leads to a decrease of phytochemical contents, which can be monitored by FTIR spectroscopy, both within the MIR and NIR ranges, whereas the use of this technique, in tandem with chemometrics, constitutes a suitable methodology for the traceability of these matrices. © 2017 Society of Chemical Industry.
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Affiliation(s)
- Nelson Machado
- UTAD-CITAB - Centre for the Research and Technology of Agro-Environmental and Biological Sciences, University of Trás-os-Montes and Alto, Vila Real, Portugal
| | - Raúl Domínguez-Perles
- UTAD-CITAB - Centre for the Research and Technology of Agro-Environmental and Biological Sciences, University of Trás-os-Montes and Alto, Vila Real, Portugal
| | - Ana Ramos
- UTAD-CITAB - Centre for the Research and Technology of Agro-Environmental and Biological Sciences, University of Trás-os-Montes and Alto, Vila Real, Portugal
| | - Eduardo As Rosa
- UTAD-CITAB - Centre for the Research and Technology of Agro-Environmental and Biological Sciences, University of Trás-os-Montes and Alto, Vila Real, Portugal
| | - Ana Irna Barros
- UTAD-CITAB - Centre for the Research and Technology of Agro-Environmental and Biological Sciences, University of Trás-os-Montes and Alto, Vila Real, Portugal
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Anzanello MJ, Yamashita G, Marcelo M, Fogliatto FS, Ortiz RS, Mariotti K, Ferrão MF. A genetic algorithm-based framework for wavelength selection on sample categorization. Drug Test Anal 2017; 9:1172-1181. [DOI: 10.1002/dta.2138] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 10/15/2016] [Accepted: 11/15/2016] [Indexed: 11/07/2022]
Affiliation(s)
- Michel J. Anzanello
- Department of Industrial Engineering; Universidade Federal do Rio Grande do Sul; Porto Alegre RS Brazil
| | - Gabrielli Yamashita
- Department of Industrial Engineering; Universidade Federal do Rio Grande do Sul; Porto Alegre RS Brazil
| | - Marcelo Marcelo
- Chemistry Institut; Universidade Federal do Rio Grande do Sul; Porto Alegre Rio Grande do Sul Brazil
| | - Flávio S. Fogliatto
- Department of Industrial Engineering; Universidade Federal do Rio Grande do Sul; Porto Alegre RS Brazil
| | - Rafael S. Ortiz
- Rio Grande do Sul Technical and Scientifical Division; Brazilian Federal Police; Porto Alegre RS Brazil
| | - Kristiane Mariotti
- Department of Pharmacy; Universidade Federal do Rio Grande do Sul; Porto Alegre Rio Grande do Sul Brazil
| | - Marco F. Ferrão
- Chemistry Institut; Universidade Federal do Rio Grande do Sul; Porto Alegre Rio Grande do Sul Brazil
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