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[IEEE 2018 40th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) - Honolulu, HI (2018.7.18-2018.7.21)] 2018 40th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) - Non-invasive method to monitor molecular changes in human stratum corneum during acute barrier disruption using reflectance NIR spectroscopy
摘要： Stratum corneum is the outer most part of skin for barrier function. Disorder in stratum corneum is related with many skin diseases including acne, atopic dermatitis and psoriasis. In developed countries, about 20% of the population has disorder in the barrier function of stratum corneum. Adhesive tape stripping is a method to disrupt skin barrier function in studying disorder in stratum corneum. In this study, we obtained NIR (Near-Infrared) spectrum of human skin after tape stripping. Changes in skin spectra after barrier disruption were investigated through principal component analysis (PCA) of spectrum. PCA analysis revealed that peaks for –NH stretching and –CH vibration mainly contributed to the spectral variation caused by barrier disruption. Furthermore, second derivative of spectrum revealed that acute barrier disruption contributes to spectral changes in the region related with secondary structure of protein, lipid and water associated with lipid in stratum corneum. We demonstrated that acute barrier disruption affected features in NIR spectrum. These spectral changes revealed that acute barrier disruption affected keratin protein and ceramide in human stratum corneum. These results suggest that NIR spectroscopy can be used to monitor changes in filamentous network and lamellar structure in stratum corneum. NIR spectroscopy can provide non-invasive method to investigate skin disease related with barrier disruption by monitoring disturbance in protein and lipid structure in stratum corneum.
关键词： protein,barrier disruption,Stratum corneum,tape stripping,water,NIR spectroscopy,lipid
更新于2025-11-14 15:14:40
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Analysis of NIR spectroscopic data using decision trees and their ensembles
摘要： Decision trees and their ensembles became quite popular for data analysis during the past decade. One of the main reasons for that is current boom in big data, where traditional statistical methods (such as, e.g., multiple linear regression) are not very efficient. However, in chemometrics these methods are still not very widespread, first of all because of several limitations related to the ratio between number of variables and observations. This paper presents several examples on how decision trees and their ensembles can be used in analysis of NIR spectroscopic data both for regression and classification. We will try to consider all important aspects including optimization and validation of models, evaluation of results, treating missing data and selection of most important variables. The performance and outcome of the decision tree-based methods are compared with more traditional approach based on partial least squares.
关键词： Decision trees,Classification and regression trees,Random forests,NIR spectroscopy
更新于2025-09-23 15:23:52
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Detection of the adulteration of extra virgin olive oil by near-infrared spectroscopy and chemometric techniques
摘要： Introduction and Objectives: Due to the value of extra virgin olive oil (EVOO), adulteration has become an important issue in the industry, which has created demand for quick and inexpensive fraud detection testing. In contrast to many current food fraud detection methods, near-infrared spectroscopy (NIRS) can be inexpensive and convenient by minimizing sample preparation and measurement times. In this study, we developed a method using NIRS and chemometrics to detect adulteration of EVOO with other edible oil types that does not require sample preparation and can be completed in less than 10 min. Methods, Results, and Discussions: First, a single EVOO was adulterated with corn oil from 2.7% to 25% w/w. Spectra for the unadulterated sample and its adulterated counterparts were measured. A principal component analysis (PCA) scores plot showed separation between the adulterated mixtures and the unadulterated sample, which demonstrated that the developed method could detect as low as 2.7% w/w adulteration if an unadulterated sample of the oil in question is provided. To study adulteration detection without an unadulterated sample for reference, the spectra of unadulterated samples and samples adulterated with corn, sunflower, soybean, and canola oils were measured. A PCA with soft independent modelling of class analogy was used for adulteration detection. Lower limits of adulteration detection for corn, sunflower, soybean, and canola oils were found to be approximately 20%, 20%, 15%, and 10%, respectively. Conclusions: These results demonstrate that the developed method can be used to rapidly screen for adulterated olive oils.
关键词： principal component analysis,olive oil adulteration,chemometrics,NIR,spectroscopy
更新于2025-09-23 15:23:52
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Maturity prediction of papaya using NIR spectroscopy
摘要： The use of NIR spectroscopy was evaluated to predict the maturity of papaya ‘IPB 1’ non-destructively during harvest time. The maturity was observed from the changes in water content, protein and soluble solid content. Samples of papaya were harvested at 14 days before commercial harvest date and continued for 7, 4 and 0 days later. NIRFlex N-500 (Büchi Labortechnik AG, Flawil, Switzerland) with spectral range of 1000-2400 nm was used as spectral acquisition of papaya in reflection mode. After dividing 124 spectra into calibration set and 62 spectra as independent prediction set, spectra in the calibration set were subjected to a partial least square method with pre-treatment processing to establish calibration model. Validation of calibration models on the independent prediction set indicated that the prediction accuracy with coefficient of determination (R2), SEC and SEP were 0.85, 0.59 and 0.58 for water content; 0.81, 0.1 and 0,1 for protein content and 0.90, 0.56, 0.76 for soluble solid content. It is concluded that NIR spectroscopy coupled with PLS models can be adopted for predicting maturity of papaya based on the water content, protein and soluble solid content.
关键词： non‐destructive,maturity,green mature papaya,NIR spectroscopy
更新于2025-09-23 15:23:52
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Spectroscopy approach to methanol detection in waste fat methyl esters
摘要： Second-generation biodiesel manufactured from waste cooking oils (WCO) and inedible animal fats (AF) are one of the alternatives to the first generation (1G) vegetable oil-based biodiesel. In this study, a quality control method is proposed to evaluate methanol content in waste fat methyl esters and is based on near infrared spectroscopy (NIR) combined with multivariate analysis. More specifically, calibration models are constructed using partial least squares regression (PLS) for the prediction of methanol content in rapeseed oil methyl ester (ROME), waste cooking oil methyl ester (WCOME), chicken fat methyl ester (CFME) and pork fat methyl ester (PFME) by Vis-NIR spectrometer. The calibration models are based on the absorbance spectra and computed data from five wavelength regions of 400–2170 nm, 780–2170 nm, 1400–2170 nm, 1400–1600 nm and 1970–2170 nm. For the cases with the highest prediction ability obtained in this study, the coefficient of determination of the model's goodness-of-fit for methanol concentrations range 0–5% (v/v) was R2 N 0.990, and for concentrations 0–1% (v/v) was R2 N 0.994, indicating the spectroscopic approach effectiveness in methanol content detection relevant to the biofuel quality assessment. A pseudo-univariate limits of detection (LODpu) and quantification (LOQpu) as well as ratio of performance to deviation (RPD) were used to confirm the validity and to evaluate the practical applicability of developed models. In addition, the obtained results indicate the possibility of developing a transmission sensor for online monitoring of the production process and the quality of biofuel.
关键词： PLS calibration models,Waste cooking oil,Animal fat biofuel,Vis-NIR spectroscopy
更新于2025-09-23 15:21:21
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The application of proximal visible and near-infrared spectroscopy to estimate soil organic matter on the Triffa Plain of Morocco
摘要： Soil organic matter (SOM) is a fundamental soil constituent. The estimation of this parameter in the laboratory using the classical method is complex time-consuming and requires the use of chemical reagents. The objectives of this study were to assess the accuracy of two laboratory measurement setups of the VIS-NIR spectroscopy in estimating SOM content and determine the important spectral bands in the SOM estimation model. A total of 115 soil samples were collected from the non-root zone (0-20 cm) of soil in the study area of the Triffa Plain and then analysed for SOM in the laboratory by the Walkley–Black method. The reflectance spectra of soil samples were measured by two protocols, Contact Probe (CP) and Pistol Grip (PG)) of the ASD spectroradiometer (350-2500 nm) in the laboratory. Partial least squares regression (PLSR) was used to develop the prediction models. The results of coefficient of determination (R2) and the root mean square error (RMSE) showed that the pistol grip offers reasonable accuracy with an R2 = 0.93 and RMSE = 0.13 compared to the contact probe protocol with an R2 = 0.85 and RMSE = 0.19. The near-Infrared range were more accurate than those in the visible range for predicting SOM using the both setups (CP and PG). The significant wavelengths contributing to the prediction of SOM for (PG) setup were at: 424, 597, 1432, 1484, 1830 ,1920, 2200, 2357 and 2430 nm, while were at 433, 587, 1380, 1431, 1929, 2200 and 2345 nm for (CP) setup.
关键词： soil organic matter,SOM analysis.,VIS-NIR spectroscopy,reflectance spectra,SOM estimation
更新于2025-09-23 15:21:01
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Effect of fruit moving speed on online prediction of soluble solids content of apple using Vis/NIR diffuse transmission
摘要： The effect of fruit moving speed on online prediction of soluble solids content (SSC) of “Fuji” apples based on visible and near-infrared (Vis/NIR) spectroscopy was studied. Diffuse transmission spectra between 615 and 1,045 nm were collected with a commercial online system at speeds of 0.3 m/s (S1), 0.5 m/s (S2), and 0.7 m/s (S3). Compensation models for SSC of each speed alone (local models) and all speeds (global model) were established using partial least squares (PLS). For global model, spectra of each sample were divided into three parts (P1, P2, and P3), three kinds of spectra partition combinations (P12, P13, and P23) were established. Results showed that S3 performed better and the influence of speed on spectra greatly affected SSC evaluation accuracy between local models. Comparatively, global model was insensitive to fruit moving speed variation and effective wavelengths (EWs) selected by competitive adaptive reweighted sampling (CARS) after Savitzky–Golay smoothing (SGS) achieved better results than local models. Importantly, 36 EWs selected by CARS after SGS of global-P13 model achieved the best results with rp and RMSEP of 0.8419, 0.8895, 0.8948 and 0.6281, 0.5318, 0.5196(cid:1)Brix, respectively. Generally, global-P13 model with EWs is promisingly applied to online SSC prediction of apple by Vis/NIR diffuse transmission.
关键词： soluble solids content,online prediction,effective wavelengths,competitive adaptive reweighted sampling,partial least squares,fruit moving speed,apple,diffuse transmission,Vis/NIR spectroscopy
更新于2025-09-23 15:21:01
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Monitoring of Microwave-Assisted Acid-Catalyzed Transesterification for Biodiesel Production Using FT-NIR Spectroscopy with Continuous-Flow Cell
摘要： The homogeneous microwave-assisted sulfuric acid-catalyzed transesterification of soybean oil, waste Brazil nut oil, sunflower oil and chicken fat for ethylic and methylic biodiesel production is described herein. The experiments were carried out in pilot-scale multimode reactors. The effects of the alcohol to oil molar ratio, catalyst concentration and irradiation time on the conversion to biodiesel were investigated. The transesterification reactions were performed at relatively small alcohol to oil molar ratios (9:1, 8:1 and 6:1) affording near 100% of conversion in reaction times of 60 to 120 min. Partial least squares (PLS) regression analysis using FT-NIR spectroscopy was performed to monitor the progress of the acid-catalyzed methanolysis of soybean oil. The NIR spectra were collected during the transesterification reaction with a spectrophotometric continuous-flow cell. 1H NMR spectroscopy was employed to determine the conversion percentage and used as a reference to build the PLS calibration model employing NIR spectroscopy data.
关键词： vegetable oils,sulfuric acid,FT-NIR spectroscopy,Animal fat,homogeneous acid catalysis,microwave-induced transesterification
更新于2025-09-23 15:21:01
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Vis- and NIR-Based Instruments for Detection of Black-Tip Damaged Wheat Kernels: A Comparative Study
摘要： Black-tip (BT) is a non-mycotoxic fungus that attacks wheat kernels, forming a dark brown or black sooty area at the tip of the kernel. Visual inspection, which is the approved reference method for determining the amount of BT in wheat, requires substantial time and has high potential for subjective evaluation. Three spectrometers covering the spectral ranges 950-1636 nm (Spec1), 600-1045 nm (Spec2), and 380-780 nm (Spec3) were evaluated for their ability to predict the presence of BT. Kernels were quantified into four levels: (A) sound, (B) low black-tip symptoms (BTS), (C) high BTS, and (D) BT damaged (BTD). Discriminant classification models were developed to evaluate combinations of levels. The combinations were (1) levels A, B, C, and D separately; (2) A, B+C, and D; and (3) A+B and C+D. Spectral data for 2,760 kernels obtained from 23 hard red winter (HRW) wheat samples, each comprising 30 kernels that were visually selected for each of the four levels of black-tip severity (A, B, C, and D), were collected with each spectrometer. Discriminant calibration models for each spectrometer and classification category were developed based on (1) three combinations of 17 HRW wheat samples, with the six remaining samples used for independent validation, and (2) combinations of 20 randomly selected kernels from each of the 23 HRW wheat samples as calibration samples, with the remaining ten kernels used as validation samples. Discriminant analysis was based on five wavelengths for each model. Spectra pretreatment was the standard normal variate (SNV). Results showed that all three spectrometers were capable of detecting BT damage on wheat kernels. BT classification accuracy was observed to have been affected by wheat varieties for Spec1 and Spec2 (both with NIR wavelengths) but not for Spec3, which was entirely in the visible region. The two-category classification (A+B, C+D) provided higher accuracy than the three-category (A, B+C, D) and four-category (A, B, C, D) classifications. Based on the percent correct classification and Youden’s index, Spec2 performed better in detecting sound and BTD wheat kernels, with classification accuracies of the best two-category classification calibration model ranging from 85.6% to 87.5%, compared to Spec1 at 74.8% to 78.4% and Spec3 at 76.7% to 79.2%. This study also showed the potential of using a five-wavelength model, which equates to the potential for developing simple, less expensive, high-speed photoelectric detection instruments. These instruments can serve as important tools in plant breeding, grading, or grain processing facilities to enable BT detection and, with proper selection of wavelengths, may also find applications in simultaneous single-kernel detection, measurement, and segregation of other chemical characteristics, such as protein and starch content.
关键词： Black-tip damage,Wheat,VIS,NIR,Spectroscopy
更新于2025-09-23 15:21:01
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Effect of the degree of inversion on optical properties of spinel ZnFe <sub/>2</sub> O <sub/>4</sub>
摘要： Spinel ferrites (T[M1?xFex]O[MxFe2?x]O4 with 0 ≤ x ≤ 1, where M is a bivalent metal ion and the superscripts denote tetrahedral and octahedral sites) are materials commonly used in electronics due to their outstanding magnetic properties. Thus, the effect of the degree of inversion, x, on these properties is well known. However, its effect on other properties of these materials has rarely been investigated in detail. Since ferrites gained much attention during the last decade as visible light active photocatalysts and photoelectrocatalysts, understanding the effect of the degree of inversion on the optical properties became necessary. Among photocatalytically and photoelectrocatalytically active spinel ferrites, zinc-ferrite (ZnFe2O4, ZFO) is one of the most widely studied materials. In this work, five ZFO samples with degrees of inversion varying from 0.07 to 0.20 were prepared by a solid-state reaction employing different annealing temperatures and subsequent quenching. Raman and UV-Vis-NIR spectra were measured and analyzed together with theoretical results obtained from ab initio calculations. Changes in the UV-Vis-NIR spectra associated with electronic transitions of tetrahedrally and octahedrally coordinated Fe3+ ions are distinguished. However, the optical band gap of the material remains unchanged as the degree of inversion varies. Based on the experimental and theoretical results, a new assignment for the Raman active internal modes and the electronic transitions of ZFO is proposed.
关键词： ab initio calculations,degree of inversion,zinc ferrite,spinel ferrites,optical properties,UV-Vis-NIR spectroscopy,Raman spectroscopy
更新于2025-09-19 17:15:36