Successful Applications of NIR Spectroscopy and NIR Imaging in the Food Processing Chain

Forty years ago, Near InfraRed (NIR) was considered a sleeping technique among the spectroscopic ones. Thanks to the technological advances suffered in recent decades, we can say that NIR is now a consolidated technique, and with rapidly increasing applications. After attracting more attention inside the laboratories, NIR Spectroscopy (NIRS) moved out of them, being used in companies (in-line and on-line process control), various fields (airborne devices and handheld devices), and even space (satellites). Many factors have contributed to this success story, whose end is, we believe, still far from being written. Several of the most important are cited here: the economic accessibility of powerful devices, the technical evolution of the instrumentation, and the acceptance of the use of chemometrics, whose impact in the field on NIRS is absolutely needed due to the chemical and physical features of NIR radiation. Other factors, such as the miniaturization of the instruments and the association with imaging techniques, which occurred with the launch of the 4th industrial revolution and the development of the Industry 4.0 paradigm, have been pivotal

Desarrollo y aplicación de métodos quimiométricos multidimensionales al estudio de sistemas enzimáticos

Consultable des del TDXTítol obtingut de la portada digitalitzadaEl objetivo de la tesis doctoral es la aplicación de metodologías quimiométricas multidimensionales al análisis de reacciones enzimáticas. Las reacciones enzimáticas estudiadas tienen aplicación en los campos del análisis químico en matrices biológicas y en los procesos de fermentación a escala industrial. En concreto: 1) Estudio del mecanismo de reacción en matrices biológicas y cálculo de las constantes enzimáticas en reacciones complejas. Se estudia la catálisis de mezclas de hipoxantina, xantina y ácido úrico con xantina oxidasa; en un medio controlado y en orina humana. Además, se determina cuantitativamente los analitos anteriormente mencionados en orina humana. Los perfiles cinéticos se registraron usando un espectrofotómetro Ultravioleta-Visible equipado con un detector de diodos. A este espectrofotómetro se acopló un sistema de flujo interrumpido stopped-flow. Para mantener la temperatura constante se usó un módulo «Peltier». 2) Establecimiento de una metodología para el control en tiempo real de bioprocesos. El sistema estudiado es la producción de enzimas lipasas por el microorganismo Pichia pastoris. Las medidas de fluorescencia se realizaron con un sensor de fluorescencia multidimensional conectado al bioreactor a través de una ventana de cuarzo. 3) Un objetivo no relacionado con la monitorización de reacciones enzimáticas, es el desarrollo de una práctica de laboratorio dirigida a estudiantes de cursos superiores de la licenciatura de Ciencias Químicas para la introducción a los métodos de resolución de curvas y a la quimiometría en general. Se han obtenido las siguientes conclusiones generales: 1) La introducción de la restricción del modelo cinético del sistema estudiado en el algoritmo MCR-ALS ha dado lugar a una nueva metodología de trabajo, denominada HS-MCR-ALS. Su aplicación al sistema cinético enzimático ha hecho posible: · El estudio del sistema enzimático en presencia de interferentes espectrales. · La elucidación del modelo cinético, ya que el anteriormente descrito en la bibliografía no contemplaba la degradación del ácido úrico. · La determinación de las constantes cinéticas del modelo postulado, tanto en un medio tamponado de composición conocida como en orina. 2) Se han aplicado y comparado diferentes métodos, bi o tridimensionales, de análisis multivariable cuantitativo para la determinación de xantina, hipoxantina y ácido úrico en mezclas sintéticas y en orina humana dopada. Los resultados obtenidos en la aplicación cuantitativa del HS-MCR-ALS son comparables a los resultados obtenidos mediante otros algoritmos tridimensionales, 3W-PLS1 y 3W-PLS2, y a los algoritmos bidimensionales clásicos, PLS1 y PLS2, con una mínima cantidad de muestras patrón. 3) Se ha establecido una nueva metodología de trabajo para el control en tiempo real de procesos monitorizados por fluorescencia. Se basa en el seguimiento no invasivo de la reacción mediante una sonda de fluorescencia multidimensional y en el tratamiento de la señal registrada mediante el algoritmo PARAFAC. A partir del modelo PARAFAC, aplicado a bioprocesos desarrollados en condiciones normales, se obtiene una estimación de los perfiles espectrales de los fluoróforos y de la evolución de su señal. El análisis de residuales de este modelo permite establecer límites de control (criterio Q). A partir de esa información, se monitorizó y controló en tiempo real un nuevo lote del bioproceso, siendo posible determinar el punto final de la producción de lipasas y metabolización total de sustrato sin necesidad de medidas off-line de los analitos de interés. 4) Se ha estudiado la evolución espectrofotométrica del ácido 8-hidroxiquinolina-5-sulfónico con el pH como una práctica de laboratorio para la introducción del algoritmo MCR-ALS a estudiantes de cursos superiores de la licenciatura de Químicas. Esta práctica contiene instrucciones de cómo utilizar los datos obtenidos en la valoración para poder aplicar MCR-ALS de una manera sencilla y didáctica.The main objective of this dissertation is the application of multidimensional chemometric methodologies to the kinetic analysis of enzymatic reactions. These enzymatic reactions have importance in analytical chemistry and in fermentation processes at industrial scale. This principal objective may be split into several partial objectives: 1) The study of reactions related with the catalysis of mixtures of hypoxanthine, xanthine and uric acid with xanthine oxidase with the aim of studying the reaction mechanism in biological matrices and to calculate the enzymatic constants in complex reactions. In addition, the influence of the reaction media in the enzymatic mechanism will be studied in a controlled media and in human urine. Another objective is the quantitative determination of the above mentioned analytes in urine samples by means of their catalytic reaction with xanthine oxidase. In this work different algorithms will be applied and their advantages and disadvantages will be compared. 2) Establishment of a methodology for the real time control of fermentation processes. In this sense, multidimensional tensor models will be applied to multidimensional spectrofluorimetry. The studied system will be the production of enzymes lipases throughout the microorganism Pichia pastoris. 3) Another objective linked to this thesis is the divulgation of curve resolution methods. As an example of their use, a laboratory experiment directed to students of the last courses of Chemistry Degree is presented. Multivariate curve resolution with alternating least squares (MCR-ALS) will be applied to the spectrophotometric titration of 8-hydroxyquinoline-5-sulfonic acid and the evolution of the system will be discussed. The following conclusions have been obtained: 1) The introduction in the algorithm of a restriction related with the kinetic model of the system gives raise to a new method, combining hard-modelling and soft-modelling in the HS-MCR-ALS algorithm. The following results have been obtained: · The study of the enzymatic mechanism in presence of a spectral interference. · The correct elucidation of the kinetic model. · The determination of the enzymatic constants of the proposed kinetic model in presence and absence of the interference of urine. 2) Several methods have been applied to the quantitation of hypoxanthine, xanthine and uric acid in synthetic samples and urine and their results compared. The obtained results with HS-MCR-ALS were compared with those obtained by other three-way methodologies (3W-PLS1 and 3W-PLS2) and by the classical two-way methodologies (PLS1 and PLS2). The HS-MCR-ALS algorithm shows clear advantages, such as the small amount of standards needed (one or two standard samples are enough) and the fact that they can be prepared in aqueous solution, with no need to know or include the interferences present in the samples. Furthermore, the kinetic profiles and the spectra of the compounds involved are obtained. 3) A new working methodology applied to the control and fault diagnosis of fermentation processes in real time is presented. Multidimensional fluorescence collects a great amount of information in a short period of time, so the variability related with the fluorophores is recorded. From the PARAFAC model, built with bioprocesses in normal operating conditions, an estimation of the spectral profiles of the fluorophores and the evolution of their signal is obtained. Residual analysis of the model allows establishing control limits (using Q criterion). From this information, a new batch of the culture was monitored in real-time without needing reference off-line measurements. 4) A laboratory experiment has been proposed to introduce the algorithm MCR-ALS to the upper-level students of the Chemistry Degree. The experiment includes a laboratory session were the spectrophotometric evolution of 8-hydroxyquinolin-5-sulfonic acid with pH is recorded, and other session were the students apply the MCR-ALS algorithm to the recorded data. This experiment contains instructions in how to use the obtained data using MCR-ALS in a simple and didactic manner

Issues with the detection and classification of microplastics in marine sediments with chemical imaging and machine learning

Numerous studies have attempted to detect microplastic litter directly in environmental sediments via spectral imaging and powerful classification algorithms. Spectral imaging is attractive largely due to the benefits of adding a spatial element to spectral data, the relative measuring speed, and minimal sample processing. Despite this promise, important concerns related to the spatial and spectral selectivity must be considered along with the appropriateness of classification algorithms. Here we evaluate the performance of near infrared hyperspectral imaging (NIR-HSI) and four commonly used classification algorithms on a simple test case in which images of individual microplastics of known size on top of sand were collected. The results highlight major weak points of NIR-HSI and machine learning as applied to the detection of the microplastics, with a large proportion of false positives and negatives in most of the situations studied, and alerts the reader to important concerns about the use of this methodology.This work was partially funded by Basque Government (KK 2021/00001 ELKARTEK 2021/2022). Reaha Goyetche thanks the University of the Basque Country, Spain, for her FPI grant. Leire Kortazar thanks the Spanish Ministry of Science and Innovation through project PID2020-118685RB-I00

Data reduction by randomization subsampling for the study of large hyperspectral datasets

Large amount of information in hyperspectral images (HSI) generally makes their analysis (e.g., principal component analysis, PCA) time consuming and often requires a lot of random access memory (RAM) and high computing power. This is particularly problematic for analysis of large images, containing millions of pixels, which can be created by augmenting series of single images (e.g., in time series analysis). This tutorial explores how data reduction can be used to analyze time series hyperspectral images much faster without losing crucial analytical information. Two of the most common data reduction methods have been chosen from the recent research. The first one uses a simple randomization method called randomized sub-sampling PCA (RSPCA). The second implies a more robust randomization method based on local-rank approximations (rPCA). This manuscript exposes the major benefits and drawbacks of both methods with the spirit of being as didactical as possible for a reader. A comprehensive comparison is made considering the amount of information retained by the PCA models at different compression degrees and the performance time. Extrapolation is also made to the case where the effect of time and any other factor are to be studied simultaneously.J.P Cruz-Tirado acknowledges scholarship funding from FAPESP, grant number 2020/09198–1

Application of hyperspectral imaging and chemometrics for classifying plastics with brominated flame retardants

Most plastics need to incorporate flame retardants to meet fire safety standards requirements. The amount and the type of flame retardants can differ, so that in waste plastics a large variety of polymers and flame retardants can be found. The recycling of plastics containing flame retardants is increasing. However, only plastics of the same polymer type and the same additive content can be recycled together. Three models based on different chemometrics techniques applied to hyperspectral imaging in the near infrared range were developed [partial least square-discriminant analysis, decision tree (DT) and hierarchical model (HM)]. Optimal results were obtained for all classification techniques. HM shows the highest error at all levels due to the noisy spectra of the black plastics. However, DT classification gave outstanding results, considering that the sensitivity was higher than 0.9 in all cases. Thus, the application of DT with hyperspectral imaging could be used to sort plastic samples with respect to the type of polymer and the flame retardant used with a high degree of accuracy in an automated way. These findings are highly valuable for the plastic and waste management industries

Review and classification of trajectory summarisation algorithms: From compression to segmentation

With the continuous development and cost reduction of positioning and tracking technologies, a large amount of trajectories are being exploited in multiple domains for knowledge extraction. A trajectory is formed by a large number of measurements, where many of them are unnecessary to describe the actual trajectory of the vehicle, or even harmful due to sensor noise. This not only consumes large amounts of memory, but also makes the extracting knowledge process more difficult. Trajectory summarisation techniques can solve this problem, generating a smaller and more manageable representation and even semantic segments. In this comprehensive review, we explain and classify techniques for the summarisation of trajectories according to their search strategy and point evaluation criteria, describing connections with the line simplification problem. We also explain several special concepts in trajectory summarisation problem. Finally, we outline the recent trends and best practices to continue the research in next summarisation algorithms.The author(s) disclosed receipt of the following financial support for the research, authorship and/or publication of this article: This work was funded by public research projects of Spanish Ministry of Economy and Competitivity (MINECO), reference TEC2017-88048-C2-2-

The development and fields of influence

Una versión preliminar de este trabajo fue presentada en la XVI World Economy Meeting (Cádiz, España, 2014). De igual forma, los autores quieren dejar de manifiesto el aporte que han realizado los árbitros anónimos a este artículo por medio de sus comentarios y sugerencias y, manifestar que, cualquier error u omisión es de nuestra responsabilidad.Utilizando las tablas insumo-producto de la OCDE, distribuidas en tres periodos de tiempo: próximas a los años 1995, 2000 y 2005, se establece como objetivo analizar la evolución de las estructuras de dichas economías y de sus sectores, así como comprobar si existen semejanzas estructurales entre ellas en función de su producto interior bruto (PIB) per cápita medido a paridad de poder adquisitivo (ppp). Para comparar las similitudes en las estructuras económicas y sus cambios, se utilizó la técnica de Campos de Influencia (CdI). Los resultados revelan que las economías tienden a ser estables en sus estructuras económicas y que estas son similares de acuerdo a sus niveles de desarrollo medido como PIB per cápita a ppp y profusión de sus CdI, excepto por dos países que, con un bajo PIB per cápita, presentaron estructuras de economías desarrolladas.By using OECD Input-Output in three different periods of time: mid-1990’s, beginning and end of the 2000’s, we discuss the evolution of their economic structures and their sectors along with a comparison among their structural similarities, measures by their Gross Domestic Product (GDP) per capita in purchaser’s power parities (ppp). Structural changes and similarities are discussed using fields of influence. The results revealed that economies tend to be stable in their structures depending on their level of development and the profusion of their fields of influence, with the exception of two countries with low GDP per capita but economic structures of developed countries

SparkBWA: Speeding Up the Alignment of High-Throughput DNA Sequencing Data

Next-generation sequencing (NGS) technologies have led to a huge amount of genomic data that need to be analyzed and interpreted. This fact has a huge impact on the DNA sequence alignment process, which nowadays requires the mapping of billions of small DNA sequences onto a reference genome. In this way, sequence alignment remains the most time-consuming stage in the sequence analysis workflow. To deal with this issue, state of the art aligners take advantage of parallelization strategies. However, the existent solutions show limited scalability and have a complex implementation. In this work we introduce SparkBWA, a new tool that exploits the capabilities of a big data technology as Spark to boost the performance of one of the most widely adopted aligner, the Burrows-Wheeler Aligner (BWA). The design of SparkBWA uses two independent software layers in such a way that no modifications to the original BWA source code are required, which assures its compatibility with any BWA version (future or legacy). SparkBWA is evaluated in different scenarios showing noticeable results in terms of performance and scalability. A comparison to other parallel BWA-based aligners validates the benefits of our approach. Finally, an intuitive and flexible API is provided to NGS professionals in order to facilitate the acceptance and adoption of the new tool. The source code of the software described in this paper is publicly available at https://github.com/citiususc/SparkBWA, with a GPL3 licenseThis work was supported by Ministerio de Economía y Competitividad (Spain) (http://www.mineco.gob.es) grants TIN2013-41129-P and TIN2014-54565-JIN. There was no additional external funding received for this studyS

Data Mining of Polymer Phase Transitions upon Temperature Changes by Small and Wide-Angle X-ray Scattering Combined with Raman Spectroscopy

The complex physical transformations of polymers upon external thermodynamic changes are related to the molecular length of the polymer and its associated multifaceted energetic balance. The understanding of subtle transitions or multistep phase transformation requires real-time phenomenological studies using a multi-technique approach that covers several length-scales and chemical states. A combination of X-ray scattering techniques with Raman spectroscopy and Differential Scanning Calorimetry was conducted to correlate the structural changes from the conformational chain to the polymer crystal and mesoscale organization. Current research applications and the experimental combination of Raman spectroscopy with simultaneous SAXS/WAXS measurements coupled to a DSC is discussed. In particular, we show that in order to obtain the maximum benefit from simultaneously obtained high-quality data sets from different techniques, one should look beyond traditional analysis techniques and instead apply multivariate analysis. Data mining strategies can be applied to develop methods to control polymer processing in an industrial context. Crystallization studies of a PVDF blend with a fluoroelastomer, known to feature complex phase transitions, were used to validate the combined approach and further analyzed by MVA

Calidad de vida en pacientes oncológicos un año después de finalizado el tratamiento

Objetive: To describe the Quality of Life (QL) parameters one year after than the onco¬logy treatment was finished. Methods: 53 patients were assessed using semi-structured interviews, standardized ques¬tionnaires and records covered by the patient and doctor. Results: The total scores of QL were high. However, a high prevalence of chronic symptoms as pain (39.6%), fatigue (37.7%), sleep disturbances (32.1%), lost of appetite (18.9%) and depressing mood (41.4%) was described by the patients. Moreover, the emo¬tional state, daily life and leisure activities were the aspects of the patients life more affected through that year. Conclusions: The total score of QL is an unspecific figure but no the others variables that have a great effect on the oncology pa¬tient through the treatment. On these specific variables intervention are required.Objetivo: Describir los parámetros y los predictores de la CV un año después de finalizado el tratamiento oncológico. Método: Se evaluaron un total de 53 pacientes mediante entrevistas semiestructuradas, cuestionarios estandarizados y autoregistros cumplimentados por el paciente y el médico. Resultados: Las valoraciones generales de calidad de fueron altas. Se encontró una alta prevalencia de síntomas experimentados de forma continua como el dolor (39,6%), cansancio (37,7%), alteraciones del sueño (32,1%) y perdida de apetito (18,9%). El estado de ánimo deprimido fue referido por un 41,4% de los pacientes. Los cambios emocionales, en las actividades domésticas y en el ocio fueron los aspectos más alterados de la rutina del paciente. En las valoraciones de CV realizadas por el paciente y el médico influyeron diversas y distintas variables. Conclusiones: Las valoraciones globales de CV son puntuaciones inespecíficas mientras que son aspectos concretos y distintos en cada momento del proceso oncológico los que afectan a la CV de los pacientes y sobre los que se requerirían intervenciones específicas