Sensitivity and specificity of PLS-class modelling for five sensory characteristics of dry-cured ham using visible and near infrared spectroscopy [An

About Sensitivity and specificity of PLS-class modelling for five sensory characteristics of dry-cured ham using visible and near infrared spectroscopy [An article from: Analytica Chimica Acta] detail

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Sensitivity and specificity of PLS-class modelling for five sensory characteristics of dry-cured ham using visible and near infrared spectroscopy [An article from: Analytica Chimica Acta] Description

This digital document is a journal article from Analytica Chimica Acta, published by Elsevier in . The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.

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The two objectives of this work were to evaluate near infrared reflectance spectroscopy (NIR) as a tool for on-line classification of dry-cured ham samples according to their sensory characteristics and propose a method for obtaining a set of qualified class models that enables accurate decisions to be taken. With these aims, 117 dry-cured ham samples were classified by expert judges as compliant or non-compliant concerning sensory variables as pastiness, colour, crusting, marbling and ring colour. These samples were also scanned using a remote reflectance fiber optic probe. Each class model built for each sensory variable is evaluated for its sensitivity and specificity, parameters related with the probability of false non-compliance (@a) and false compliance (@b) of ''H"0: the sample is compliant'' hypothesis test. With the five sets of PLS-class modelling the five risk curves, graphs @b versus @a, are estimated. It is therefore possible to choose the risks of false compliance and false non-compliance for each sensorial variable according to the needs of the decision-maker.

Near infrared reflectance spectroscopy and multivariate analysis in enology [An article from: Analytica Chimica Acta]

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• Published on: 2004-11-29
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Near infrared reflectance spectroscopy and multivariate analysis in enology [An article from: Analytica Chimica Acta] Description

This digital document is a journal article from Analytica Chimica Acta, published by Elsevier in 2004. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.

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A study of the feasibility of near infrared reflectance spectroscopy (NIRS) for analytical monitoring in wineries is presented, in which equations for the determination or screening of the commonest enological parameters are proposed. The training and validation sets to develop NIR general equations were built with samples (180) from different apellation d'origine, different wine types, etc. By the calibration step (partial least squares regression and cross-validation were used for multivariate calibration), major components such as ethanol, volumic mass, total acidity, pH, glycerol, colour, tonality and total polyphenol index are accurate determined by the proposed equations as compared with the reference data obtained by the official and standard methods-determination coefficients (R^2) were higher than 0.800 (and higher than 0.900 most times) and standard error cross-validation (SECV) values were close to those of the reference methods. The proposed method also offers screening capability for components such as volatile acidity (R^2 = 0.481), organic acids (R^2 = 0.432 for malic acid, R^2 = 0.544 for tartaric acid, R^2 = 0.541 for gluconic acid)-with the exception of the accurate determination of lactic acid (0.860 and 0.35gl^-^1 for R^2 and SECV, respectively)-reducing sugars (R^2 = 0.705) and total sulphur dioxide (R^2 = 0.615). In equations validation, the correlation between the reference and NIRS methods was tested, and slope and bias values statistically not different from 1 and 0, respectively, were obtained for most parameters.

Content uniformity and tablet hardness testing of intact pharmaceutical tablets by near infrared spectroscopy [An article from: Analytica Chimica Acta

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Content uniformity and tablet hardness testing of intact pharmaceutical tablets by near infrared spectroscopy [An article from: Analytica Chimica Acta] Description

This digital document is a journal article from Analytica Chimica Acta, published by Elsevier in . The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.

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The use of process analytical technologies by the pharmaceutical industry is a response to its growing need for improved productivity in order to face the increasing competition in this field. In this work, we explored the use of near infrared spectroscopy (NIRS) for the determination of physical (tablet hardness) and chemical parameters (active principle and content uniformity) in intact individual pharmaceutical tablets. Quantization was done by using a Partial Least Squares 1 (PLS1) calibration model constructed from laboratory calibration samples that were prepared by mixing the active principle and excipients, and pressing the mixture into tablets. The compaction pressure to be applied to the powder was previously determined by using another PLS1 model that allows calculating it from production tablets. The NIRS method used to quantify the active principle is simpler as the calibration set encompasses the variability sources present in production samples; also, it allows individual tablets to be analysed. The proposed method was validated in accordance with the International Conference on Harmonization (ICH) and The European Agency for the Evaluation of Medicinal Products (EMEA) guidelines, and found to be fit for its intended purpose. pose.

Combination of mid- and near-infrared spectroscopy for the [An article from: Analytica Chimica Acta]

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• Published on: 2006-07-07
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Combination of mid- and near-infrared spectroscopy for the [An article from: Analytica Chimica Acta] Description

This digital document is a journal article from Analytica Chimica Acta, published by Elsevier in 2006. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.

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The combination of infrared (MIR) and near-infrared (NIR) spectroscopy has been employed for the determination of important quality parameters of beers, such as original and real extract and alcohol content. A population of 43 samples obtained from the Spanish market and including different types of beer, was evaluated. For each technique, spectra were obtained in triplicate. In the case of NIR a 1mm pathlength quartz flow cell was used, whereas attenuated total reflectance measurements were used in MIR. Cluster hierarchical analysis was employed to select calibration and validation data sets. The calibration set was composed of 15 samples, thus leaving 28 for validation. A critical evaluation of the prediction capability of multivariate methods established from the combination of NIR and MIR spectra was made. Partial least squares (PLS) and artificial neural networks (ANN) were evaluated for the treatment of data obtained in each individual technique and the combination of both. Different parameters of each methodology were optimized. A slightly better predictive performance was obtained for NIR-MIR combined spectra, and in all the cases ANN performs better than PLS, which may be interpreted from the existence of some non-linearity in the data. The root-mean-sqare-error of prediction (RMSEP) values obtained for the combined NIR-MIR spectra for the determination of real extract, original extract and ethanol were 0.076% w/w, 0.14% w/w and 0.091% v/v.

Anticipatory anxiety-induced changes in human lateral prefrontal cortex activity [An article from: Biological Psychology]

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• Published on: 2007-01-01
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Anticipatory anxiety-induced changes in human lateral prefrontal cortex activity [An article from: Biological Psychology] Description

This digital document is a journal article from Biological Psychology, published by Elsevier in 2007. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.

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It has been suggested that frontal brain asymmetry is associated with differences in basic emotional dimensions, particularly in activation of systems underlying avoidance-withdrawal behavior. We examined regional cerebral oxygenated hemoglobin (O"2Hb) levels in human medial prefrontal cortex (MPFC) using near-infrared reflection spectroscopy (NIRS) prior to and during anticipatory anxiety to determine if NIRS could detect any anxiety-related changes. Transient anxiety was induced in 56 normal volunteers by anticipation and a painful shock to the right-hand's median nerve. Pre- and post-anxiety affective statuses were measured using the State-Trait Anxiety Inventory (STAI) and Temperature Character Inventory (TCI). NIRS recorded from the left and right frontal brain regions. Right MPFC O"2Hb was significantly increased relative to left MPFC O"2Hb during anticipation of the shock. Right-sided O"2Hb increases were significantly correlated with the TCI Harm Avoidance subscale. These results support the hypothesis that O"2Hb levels in the right frontal region correlate with anxiety or heightened negative affect.

Kinetic analysis of reactions of Si-based epoxy resins by near-infrared spectroscopy, ^1^3C NMR and soft-hard modelling [An article from: Analytica

About Kinetic analysis of reactions of Si-based epoxy resins by near-infrared spectroscopy, ^1^3C NMR and soft-hard modelling [An article from: Analytica Chimica Acta] detail

• Published on: 2007-02-05
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Kinetic analysis of reactions of Si-based epoxy resins by near-infrared spectroscopy, ^1^3C NMR and soft-hard modelling [An article from: Analytica Chimica Acta] Description

This digital document is a journal article from Analytica Chimica Acta, published by Elsevier in 2007. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.

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Soft- and hard-modelling strategy was applied to near-infrared spectroscopy data obtained from monitoring the reaction between glycidyloxydimethylphenyl silane, a silicon-based epoxy monomer, and aniline. On the basis of the pure soft-modelling approach and previous chemical knowledge, a kinetic model for the reaction was proposed. Then, multivariate curve resolution-alternating least squares optimization was carried out under a hard constraint, that compels the concentration profiles to fulfil the proposed kinetic model at each iteration of the optimization process. In this way, the concentration profiles of each species and the corresponding kinetic rate constants of the reaction, unpublished until now, were obtained. The results obtained were contrasted with ^1^3C NMR. The joint interval test of slope and intercept for detecting bias was not significant (@a=5%).

Determination of low analyte concentrations by near-infrared spectroscopy: Effect of spectral pretreatments and estimation of multivariate detection

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• Published on: 2007-01-09
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Determination of low analyte concentrations by near-infrared spectroscopy: Effect of spectral pretreatments and estimation of multivariate detection limits [An article from: Analytica Chimica Acta] Description

This digital document is a journal article from Analytica Chimica Acta, published by Elsevier in 2007. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.

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Near infrared spectroscopy (NIRS) was used in combination with partial least squares (PLS) calibration to determine low concentrated analytes. The effect of the orthogonal signal correction (OSC) and net analyte signal (NAS) pretreatments on the models obtained at concentrations of analyte near its detection limit was studied. Both pretreatments were found to accurately resolve the analyte signal and allow the construction of PLS models from a reduced number of factors; however, they provided no substantial advantage in terms of %RSE for the prediction samples. Multiple methodologies for the estimation of detection limits could be found in the bibliography. Nevertheless, detection limits were determined by a multivariate method based on the sample-specific standard error for PLS regression, and compared with the univariate method endorsed by ISO 11483. The two methods gave similar results, both being effective for the intended purpose of estimating detection limits for PLS models. Although OSC and NAS allow isolating the analyte signal from the matrix signal, they provide no substantial improvement in terms of detection limits. The proposed method was used to the determine 2-ethylhexanol at concentrations from 20 to 1600ppm in an industrial ester. The detection limit obtained, round 100ppm, testifies to the ability of NIR spectroscopy to detect low concentrated analytes.

Non-Invasive Measurement of the Neonatal Cerebral & Splanchnic Circulation by Near-Infrared Spectroscopy (Acta Biomedica Lovaniensia, 295)

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• Amazon Sales Rank: #6465337 in Books
• Published on: 2003-11
• Original language: English
• Binding: Paperback
• 170 pages

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Decrease in prefrontal hemoglobin oxygenation during reaching tasks with delayed visual feedback: a near-infrared spectroscopy study [An article from:

About Decrease in prefrontal hemoglobin oxygenation during reaching tasks with delayed visual feedback: a near-infrared spectroscopy study [An article from: Cognitive Brain Research] detail

• Published on: 2004-08-01
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Decrease in prefrontal hemoglobin oxygenation during reaching tasks with delayed visual feedback: a near-infrared spectroscopy study [An article from: Cognitive Brain Research] Description

This digital document is a journal article from Cognitive Brain Research, published by Elsevier in 2004. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.

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Visual feedback of hand movement is crucial to accurate reaching. Although previous studies have extensively examined spatial alteration of visual feedback (e.g., prism adaptation), temporal delay of visual feedback has been less explored. In the present study, we investigated the effect of delayed visual feedback of the moving hand in a reaching task. The prefrontal cortical activity was measured by near-infrared spectroscopy (NIRS). Twelve subjects performed reaching tasks under two conditions where visual feedback of their own hand was delayed by 200 ms (delay condition) or 0 ms (normal condition). Introducing the visual feedback delay significantly disrupted the reaching performance, although the subjects gradually adapted to the delay during the experiment. There was a clear tendency to overreach the target in the delay condition, even after the reaching movement had been practiced sufficiently in the normal condition. We observed marked oxy- and total-Hb decreases in the dorsal prefrontal area in the delay conditions. The decrease began shortly after task onset and diminished during the rest period, indicating that the decrease was task-induced. Furthermore, the oxy- and total-Hb decreases were significantly correlated with task performance-the degree of decrease was larger as the subject made more errors. We suggest that the decreases in oxy- and total-Hb at the dorsal prefrontal area are related with the visuomotor recalibration process.

Atomic and Nuclear Analytical Methods: XRF, Mössbauer, XPS, NAA and Ion-Beam Spectroscopic Techniques

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• Amazon Sales Rank: #2367495 in Books
• Published on: 2007-06-11
• Original language: English, German
• Number of items: 1
• Binding: Hardcover
• 376 pages

Atomic and Nuclear Analytical Methods: XRF, Mössbauer, XPS, NAA and Ion-Beam Spectroscopic Techniques Description

This book is a blend of analytical methods based on the phenomenon of atomic and nuclear physics. It comprises comprehensive presentations about X-ray Fluorescence (XRF), Mössbauer Spectroscopy (MS), X-ray Photoelectron Spectroscopy (XPS), Neutron- Activation Analysis (NAA), Particle Induced X-ray Emission Analysis (PIXE), Rutherford Backscattering Analysis (RBS), Elastic Recoil Detection (ERD), Nuclear Reaction Analysis (NRA), Particle Induced Gamma-ray Emission Analysis (PIGE), and Accelerator Mass Spectrometry (AMS). These techniques are commonly applied in the fields of medicine, biology, environmental studies, archaeology or geology et al. and pursued in major international research laboratories.