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Vibrational and photoluminescence properties of polydiphenylamine doped with silicotungstic acid heteropolyanions and their composites with reduced graphene oxide
摘要： In this work, the influence of silicotungstic acid concentration on the diphenylamine (DPA) electropolymerization in the absence and the presence of reduced graphene oxide (RGO) is studied. The optical properties of the composites based on polydiphenylamine (PDPA) doped with the H4SiW12O40 heteropolyanions and RGO are investigated by Raman scattering, IR absorption spectroscopy and photoluminescence (PL). The presence of RGO induces an up-shift of the oxidation maximum of the DPA, as a result of a covalent functionalization process of graphene sheets with the polymer in the doped state. The deposition of PDPA onto RGO sheets surface is confirmed by the Raman scattering studies. Regardless of the H4SiW12O40 concentration, an up-shift of the IR bands from 910 to 1014 cm-1 is reported as a consequence of the compensation of positive charges of PDPA macromolecular chains with of the H4SiW12O40 heteropolyanions. An enhancement in the absorbance of the IR bands situated in the spectral range 750-1050 cm-1 accompanied of a decrease in the relative intensity of the PL bands of PDPA and their composites with RGO, as increasing the H4SiW12O40 concentration, is reported. In the presence of RGO, a change in the PDPA PL spectra profile is also highlighted.
关键词： Photoluminescence,Raman scattering,Polydiphenylamine,Reduced graphene oxide,Silicotungstic acid,Infrared spectroscopy
更新于2025-09-19 17:15:36
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Maintaining the predictive abilities of egg freshness models on new variety based on VIS-NIR spectroscopy technique
摘要： This research was performed to study calibration model transfer between White Leghorns eggs and Bantam eggs for prediction of egg freshness by visible near infrared (VIS-NIR) spectroscopy. Transmission spectra of the two varieties were acquired in the equatorial region of the eggs. And albumen pH as the freshness evaluating parameter was measured using traditional destructive methods. After outliers were eliminated by Mahalanobis distance combined with principal component analysis (PCA), partial least squares regression (PLSR) with different preprocessing methods was used to develop prediction models. Global updating, direct standardization (DS) and slope/bias correction (SBC) were evaluated to transfer calibration models from one variety to another. The Kennard-Stone (KS) algorithm was used to select standardization samples. White Leghorns eggs and Bantam eggs as the master variety in turn were compared to find superior master variety. Application of the slope/bias correction (SBC) algorithm obtained the best prediction results of albumen pH. And the better slope/bias correction (SBC) transfer performance with a rp of 0.908 and a RMSEP of 0.133 was found when Bantam eggs were as the superior master variety.
关键词： Slope/bias correction,Visible near infrared spectroscopy,Direct standardization,Global updating,Egg
更新于2025-09-19 17:15:36
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Application of infrared spectroscopy as Process Analytics Technology (PAT) approach in biodiesel production process utilizing Multivariate Curve Resolution Alternative Least Square (MCR-ALS)
摘要： Process Analytical Technology means at-line collection of analytical information from the process when the reaction is in progress. Obtained information enables process engineers to better control the Critical Process Parameters and direct the reaction to desirable routs. Near-infrared spectroscopy due to its analytical features, as well as the high capability of automation, versatile sampling and spectral acquisition methods is a useful tool in process monitoring when coupled to chemometrics. The Multiple Scatter Correction preprocessing technique and Alternative Least Square method can extract spectral and concentration information of a reaction mixture simultaneously, were employed pairing with fiber optic Near-Infrared spectroscopy in 1000-2250 nm spectral region was employed to extract the analytical information from the biodiesel production process. The obtained output demonstrated appropriate results about the concentration and type of components during the process. The kinetics of the reaction was also studied using the obtained results and showed a three-stage kinetics with different rates.
关键词： MCR-ALS,Near-Infrared spectroscopy,Process Analytical Technology,Biodiesel
更新于2025-09-19 17:15:36
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EXPRESS: Use of Visible–Near-Infrared (Vis–NIR) Spectroscopy to Detect Aflatoxin B <sub/>1</sub> on Peanut Kernels
摘要： Current methods for detecting aflatoxin contamination of agricultural and food commodities are generally based on wet chemical analyses, which are time-consuming, destructive to test samples and require skilled personnel to perform, making them impossible for large-scale nondestructive screening and on-site detection. In this study, we utilized visible–near-infrared (Vis–NIR) spectroscopy over the spectral range of 400–2500 nm to detect contamination of commercial, shelled peanut kernels (runner type) with the predominant aflatoxin B1 (AFB1). The artificially contaminated samples were prepared by dropping known amounts of aflatoxin standard dissolved in methanol, onto peanut kernel surface to achieve different contamination levels. The partial least squares discriminant analysis (PLS-DA) models established using the full spectra over different ranges achieved good prediction results. The best overall accuracy of 88.57% and 92.86% were obtained using the full spectra when taking 20 and 100 parts per billion (ppb), respectively, as the classification threshold. The random frog (RF) algorithm was used to find the optimal characteristic wavelengths for identifying the surface AFB1-contamination of peanut kernels. Using the optimal spectral variables determined by the RF algorithm, the simplified RF-PLS-DA classification models were established. The better RF-PLS-DA models attained the overall accuracies of 90.00% and 94.29% with the 20 ppb and 100 ppb thresholds, respectively, which were improved compared to using the full spectral variables. Compared to using the full spectral variables, the employed spectral variables of the simplified RF-PLS-DA models were decreased by at least 94.82%. The present study demonstrated that the Vis–NIR spectroscopic technique combined with appropriate chemometric methods could be useful in identifying AFB1 contamination of peanut kernels.
关键词： Vis–NIR,PLS-DA,peanut kernel,visible–near-infrared spectroscopy,random frog,Aflatoxin,partial least squares discriminant analysis
更新于2025-09-19 17:15:36
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A feasibility study on quantitative analysis of low concentration methanol by FT-NIR spectroscopy and aquaphotomics
摘要： Methanol content is a key parameter in the fermentation industry. However, the methanol concentration during fermentation is usually quite low, it's necessary to find a method to measure methanol with low content, even indirectly. Near infrared spectroscopy (NIRS) technology is rapid and non-destructive, which can provide analytical solutions for components that represent approximately 1%. Aquaphotomics gives the chance to dig into the information remaining hidden in the NIR spectra, which shows a distinct advantage if the target object is presented in lower concentrations. Therefore, NIRS combined with aquaphotomics was introduced in this study to prove the feasibility for methanol determination at 0.1%-2.5% (v/v) in aqueous solutions. Determination coefficient of calibration (R2 c), validation (R2 cv), root mean square error of calibration (RMSEC), validation (RMSEP) and cross validation (RMSECV) were applied to verify the performance of the partial least squares regression (PLSR) models, and the corresponding values of best model were 0.999, 0.999, 1.000, 0.0204%, 0.0277%, 0.0142%, respectively. Our successfully result indicated that NIRS technique combined with aquaphotomics may open a new perspective in methanol determination.
关键词： Aquaphotomics,Low concentration,Methanol,Near infrared spectroscopy
更新于2025-09-19 17:15:36
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Wearable-band Type Visible-Near Infrared Optical Biosensor for Non-invasive Blood Glucose Monitoring
摘要： Diabetes is a worldwide-serious problem that can only be delayed or prevented by a regular monitoring of blood glucose (BG) concentration level. Continuous monitoring systems allow subjects to prepare the diabetes management strategy and prevent the long-term complications diseases. Until now, most studies utilize various biofluids such as sweat, tears and saliva that have serious unresolved setback such as expensive material, sensor stability, sensor calibration and long-settling time. Therefore, we developed a novel BG sensor which is cost efficient and highly wearable with a small data acquisition time window that allow a non-invasive, long-term continuous blood glucose monitoring (CGM) system. The novel biosensor exploits a unique information of the pulsatile to continuous components of the arterial blood volume pulsation during the change of blood glucose (BG) concentration at the wrist tissue. The reflected optical signal was measured in the combine visible-near infrared (Vis-NIR) spectroscopy. An in-vivo experiment which enclosed 12 volunteers in a two-hour modified carbohydrate-rich meals reached the average correlation coefficient (????) between the estimated and reference BG concentration of 0.86, with the standard prediction error (SPE) of 6.16 mg/dl. Moreover, the full-day experiment was also conducted to test the reliability of the proposed sensor. Results showed that the created model in the previous day, may estimate a full-day BG concentration which was done in next day with an adequate performance.
关键词： Wearable Sensor,Optical Biosensor,Noninvasive Measurement,Visible-Near Infrared Spectroscopy,Diabetes,Continuous Blood Glucose Monitoring
更新于2025-09-19 17:15:36
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Intravascular Molecular Imaging to Detect High-Risk Vulnerable Plaques: Current Knowledge and Future Perspectives
摘要： Purpose of Review To describe vulnerable plaque pathobiology and summarize potential targets for molecular imaging with a focus on intravascular near-infrared fluorescence (NIRF) and its translatable applications. Recent Findings Structural imaging alone is unable to precisely identify high-risk plaques in patients with coronary artery disease (CAD). Intravascular near-infrared fluorescence (NIRF) imaging is an emerging translational approach that can image specific in vivo molecular processes and cells that characterize vulnerable plaques. High-priority NIRF targets imaged by intravascular NIRF imaging thus far include macrophages, cathepsin protease activity, oxidized low-density lipoprotein (oxLDL), and abnormal endothelial permeability. The newest generation of NIRF catheters is multimodal in nature and combines NIRF with either IVUS or OCT, providing simultaneous co-registered morphological and pathobiological assessment of atherosclerotic plaques. While most intravascular NIRF studies have been performed in a preclinical environment, a first-in-human NIR autofluorescence-OCT trial has recently been performed. These developments suggest that clinical intravascular NIRF molecular imaging will be available within the next 3 years. Summary Molecular imaging is a powerful approach to enhance our understanding of atherosclerosis pathophysiology. Intravascular NIRF/OCT and NIRF/IVUS molecular imaging is nearing its use in atherosclerosis patients and will initially leverage indocyanine green (ICG) as an FDA-approved NIRF agent that reports on abnormal plaque permeability. Clinical trials are needed to assess the value of intravascular NIRF imaging using ICG as well as other novel NIRF imaging agents to better understand vulnerable plaque pathobiology, event prediction, and to enable personalized pharmacotherapy of high-risk plaques and patients.
关键词： Molecular imaging,Vulnerable plaque,Near-infrared spectroscopy,OCT,Atherosclerosis,Near-infrared fluorescence,IVUS
更新于2025-09-19 17:13:59
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Local anomaly detection and quantitative analysis of contaminants in soybean meal using near infrared imaging: The example of non-protein nitrogen
摘要： The melamine scandal indicates that traditional targeted detection methods only detect the specifically listed forms of contamination, which leads to the failure to identify new adulterants in time. In order to deal with continually changing forms of adulterations in food and feed and make up for the inadequacy of targeted detection methods, an untargeted detection method based on local anomaly detection (LAD) using near infrared (NIR) imaging was examined in this study. In the LAD method, with a particular size of window filter and at a 99% level of confidence, a specific value of Global H (GH, modified Mahalanobis distance) can be used as a threshold for anomalous spectra detection and quantitative analysis. The results showed an acceptable performance for the detection of contaminations with the advantage of no need of building a ‘clean’ library. And, a high coefficient of determination (R2 LAD = 0.9984 and R2 PLS-DA = 0.9978) for the quantitative analysis of melamine with a limit of detection lower than 0.01% was obtained. This indicates that the new strategy of untargeted detection has the potential to move from passive to active for food and feed safety control.
关键词： Soybean meal,Untargeted detection,Near-infrared hyperspectral/microscopic imaging,Local anomaly detection,Near-infrared spectroscopy
更新于2025-09-19 17:13:59
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Infrared and 2-Dimensional Correlation Spectroscopy Study of the Effect of CH3NH3PbI3 and CH3NH3SnI3 Photovoltaic Perovskites on Eukaryotic Cells
摘要： We studied the effect of the exposure of human A549 and SH-SY5Y cell lines to aqueous solutions of organic/inorganic halide perovskites CH3NH3PbI3 (MAPbI3) and CH3NH3SnI3 (MASnI3) at the molecular level by using Fourier transform infrared microspectroscopy. We monitored the infrared spectra of some cells over a few days following exposure to the metals and observed the spectroscopic changes dominated by the appearance of a strong band at 1627 cm?1. We used Infrared (IR) mapping to show that this change was associated with the cell itself or the cellular membrane. It is unclear whether the appearance of the 1627 cm?1 band and heavy metal exposure are related by a direct causal relationship. The spectroscopic response of exposure to MAPbI3 and MASnI3 was similar, indicating that it may arise from a general cellular response to stressful environmental conditions. We used 2D correlation spectroscopy (2DCOS) analysis to interpret spectroscopic changes. In a novel application of the method, we demonstrated the viability of 2DCOS for band assignment in spatially resolved spectra. We assigned the 1627 cm?1 band to the accumulation of an abundant amide or amine containing compound, while ruling out other hypotheses. We propose a few tentative assignments to specific biomolecules or classes of biomolecules, although additional biochemical characterization will be necessary to confirm such assignments.
关键词： amyloid,infrared microscopy,infrared spectroscopy,perovskite,2DCOS
更新于2025-09-19 17:13:59
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EXPRESS: A Study of the Surface of Fe <sub/>3</sub> O <sub/>4</sub> @SiO <sub/>2</sub> Nanoparticles Functionalized with Different Groups Using a Photoacoustic Infrared Spectroscopic Method
摘要： A permanent development of hybrid materials based on the highly absorptive or opaque materials has prompted a need of analytical tools, which are able to overcome obstacles connected with their physicochemical features. Iron oxide (II, III) (Fe3O4) nanoparticles gained a huge attention as supporters, as they are not only easily accessible using various synthetic approaches, but they also exhibit homogeneity and paramagnetic properties, which make them easily separable materials. Nevertheless, the classic infrared spectroscopic studies might meet several problems with characterization of such systems. Therefore, infrared spectroscopy in photoacoustic mode using Fourier transform infrared–photoacoustic infrared spectroscopy (FT-IR PAS) can be an extremely sensitive and exact analytical tool for investigation of the magnetite-based hybrid materials surface. Herein, we present a synthesis of Fe3O4 nanoparticles using co-precipitation method with their subsequent encapsulation within silica matrix decorated with different silanes containing various terminal functional groups. The proper syntheses of core/shell structures were confirmed using the FT-IR PAS method. Each spectrum exhibited specific bands corresponding to vibrations of magnetite particles, silica lattice and particular surface functional groups, which strictly indicated successful grafting of silanes onto Fe3O4 surface.
关键词： PAS,Magnetite nanoparticles,Fourier transform infrared,core/shell structures,surface analysis,photoacoustic infrared spectroscopy,FT-IR PAS,FT-IR
更新于2025-09-19 17:13:59