- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Determination of water activity, total soluble solids and moisture, sucrose, glucose and fructose contents in osmotically dehydrated papaya using near-infrared spectroscopy
摘要： Near-infrared spectroscopy (NIRS) is a rapid analysis method that is widely used for quantitative determination of the major constituents in many food products. NIRS was applied in conjunction with a chemometric algorithm, namely the partial least squares regression (PLSR), to develop the optimum model for predicting the qualities of osmotically dehydrated papaya (ODP). Two hundred ODP samples were collected from commercial products and from different laboratory ODP processes with varying sucrose concentrations (35oBrix, 45oBirx, 55oBrix and 65oBrix) at 40°C for 6 hr and drying times at 60°C for 2 hr, 4 hr, 6 hr, 8 hr, 10 hr and 12 hr. All samples were divided into a calibration set (n = 140) and a validation set (n = 60) before quality determination and NIRS analysis. Samples were scanned over the NIR spectral range of 800–2400 nm in reflectance mode and their spectra were pretreated using the second derivative method. Suitable predictive models were developed by applying full wavelength PLSR and two wavelength interval selection methods, named the moving window partial least squares regression (MWPLSR) and the searching combination moving window partial least squares regression (SCMWPLSR). The results showed that SCMWPLSR provided better performance than PLSR and MWPLSR. The root mean square error of prediction values of water activity, moisture content, total soluble solids and the sucrose, glucose and fructose contents from SCMWPLSR were 0.014, 0.69% (dry basis), 0.58oBrix, 14.44 g/100 g of sample, 6.72 g/100 g of sample and 4.89 g/100 g of sample, respectively, with correlation coefficients in the range 0.981–0.994.
关键词： Moving window partial least squares regression,Searching combination moving window partial least squares regression,Near-infrared spectroscopy,Partial least squares regression,Papaya
更新于2025-09-10 09:29:36
-
Effect of measurement position on prediction of apple soluble solids content (SSC) by an on-line near-infrared (NIR) system
摘要： Near infrared spectroscopy has been widely applied in the area of rapid determination for fruits’ internal qualities. Therefore, an on-line near-infrared detection system was established to predict the SSC of apples in this study. Due to random measurement positions of apples, negative influences will be exerted on the performance of prediction models. With the aim of learning more about these influences and also compensating for them, spectra were taken at different measurement positions in the present work, including six fixed positions and a random position. Besides, the relations between these positions were investigated as well. It is also found that when the concave surfaces at apple’s calyx and stem interfered with the light path in the detection system, model’s robustness and accuracy would be deteriorated. At last, average and global spectra were used to build prediction models with comparison purpose. The optimal prediction model was established by the average spectra of seven measurement positions (RMSEC 0.356%; rc 0.947; RMSEP 0.370%; rp 0.906), which was superior to results in many previous studies. Last but not least, several suggestions on compensation for these influences were made to improve the model performance in some practical applications.
关键词： Apple,Soluble solids content,On-line,Measurement position,Near-infrared
更新于2025-09-10 09:29:36
-
Ordered polypyrrole nanorings with near-infrared spectrum absorption and photothermal conversion performance
摘要： Ordered polypyrrole nanorings (PPy NRs) morphology is synthesized by direct chemical oxidative polymerization using the composite of cetrimonium cations and peroxydisulfate anions as the soft template. The size of PPy NRs is 200nm, and the diameter of single wire is 50-70nm. These ordered nanorings display strong near-infrared (NIR) spectrum absorption and excellent photothermal conversion performance. The temperature of PPy NRs / polydimethylsiloxane (PDMS) composites is up to about 170°C under irradiation with an 808 nm laser with power of 2.2W. More important, the NIR-response materials PPy NRs /vitrimer can induce the performances of shape memory, reshaping, welding, and self-healing under different NIR irradiation power. This study designs a unique and ordered nanostructure, which achieving outstanding photothermal conversion performance.
关键词： polypyrrole,nanorings,photothermal conversion,near-infrared,vitrimer
更新于2025-09-10 09:29:36
-
Full-Spectrum Photocatalytic Activity of ZnO/CuO/ZnFe2O4 Nanocomposite as a PhotoFenton-Like Catalyst
摘要： Deriving photocatalysts by the calcination of hydrotalcite-like compounds has attracted growing interest for extending their photocatalytic activity to the visible and even near-infrared (NIR) light regions. Herein, we describe the acquisition of a ZnO/CuO/ZnFe2O4 nanocomposite with good photoFenton-like catalytic activity under UV, visible and near-infrared (NIR) light irradiation by optimizing the calcination temperature of the coprecipitation product of Zn2+, Cu2+ and Fe3+. The ZnO/CuO/ZnFe2O4 nanocomposite is composed of symbiotic crystals of ZnO, CuO and ZnFe2O4, which enable the nanocomposite to show absorption in the UV, visible and NIR light regions and to produce a transient photocurrent in the presence of H2O2 under NIR irradiation. The full-spectrum photoFenton-like catalyst shows improved performance for the degradation of methyl orange with an increasing amount of H2O2 and is very stable in the recycling process. We believe that the ZnO/CuO/ZnFe2O4 nanocomposite is a promising full-spectrum photoFenton-like catalyst for the degradation of organic pollutants.
关键词： ZnO/CuO/ZnFe2O4,photodegradation,Full-spectrum,nanocomposite,photoFenton-like catalyst,near-infrared light,photocatalysis
更新于2025-09-10 09:29:36
-
Near Infrared Nighttime Road Pedestrians Recognition Based on Convolutional Neural Network
摘要： Pedestrian recognition is the core technology of pedestrian detection in pedestrian protection systems. This paper compares and analyzes, visible and infrared images obtained via visible-spectrum, near-infrared, short-wave infrared, and long-wave infrared cameras. The results show that near-infrared camera was the best for nighttime pedestrian detection when device cost and pedestrian imaging quality were considered. This paper reports on the first time use of a self-learning softmax with a 9-layer Convolutional Neural Network (CNN) model to identify near-infrared nighttime pedestrians. 267,000 samples obtained from the near-infrared images were employed to optimize the CNN recognition model. Collected near-infrared nighttime samples had 3 categories (background, pedestrian, and cyclist or motorcyclist) and will be made publicly available for researchers use. Testing results indicated that the optimized CNN model using self-learning softmax had a competitive accuracy and potential in real-time pedestrian recognition.
关键词： softmax,pedestrian recognition,CNN,nighttime,near infrared
更新于2025-09-10 09:29:36
-
Detection of parameters in solid state fermentation of Monascus by near infrared spectroscopy
摘要： The prediction model was constructed using the near-infrared spectroscopy combined with the interval least squares support vector machine method (siLS-SVM) of moisture content and pH value change during the solid fermentation of Monascus. The predictive model was established with partial least squares regression (PLS), and the comprehensive performance of the model was evaluated by cross-validating the mean square error, absolute error value and relative error value. The findings suggest that the LS-SVM model established by siLS-SVM algorithm owns superior predictability and stability for the changes of water content and pH value in the solid fermentation of Monascus (the average relative error is 1.52% and 1.55%, respectively), which can be used for the accurate quantitative prediction. The results showed that near infrared spectroscopy could be used for rapid and non-destructive determination of water content and PH value in solid-state fermentation of Monascus, which provided a new way for optimization of solid-state fermentation process of Monascus under bran substrate.
关键词： Near-infrared spectroscopy,Prediction model,Monascus,Solid state fermentation
更新于2025-09-10 09:29:36
-
Indocyanine Green labeling for optical and photoacoustic imaging of Mesenchymal Stem Cells after in vivo transplantation
摘要： The transplantation of Mesenchymal Stem Cells (MSCs) holds great promise for the treatment of a plethora of human diseases, but new non-invasive procedures are needed to monitor the cell fate in vivo. Already largely used in medical diagnostics, the fluorescent dye Indocyanine Green (ICG) is an established dye to track limited numbers of cells by optical imaging, but it can be visualized also by Photoacoustic Imaging (PAI), which provides a higher spatial resolution than pure near infrared fluorescence imaging (NIRF). Because of its successful use in clinical and preclinical examinations, we chose ICG as PAI cell labeling agent. Optimal incubation conditions were defined for an efficient and clinically translatable MSC labeling protocol, such that no cytotoxicity or alterations of the phenotypic profile were observed, and a consistent intracellular uptake of the molecule was achieved. Suspensions of ICG-labeled cells were both optically and optoacoustically detected in vitro, revealing a certain variability in the photoacoustic spectra acquired by varying the excitation wavelength from 680 to 970 nm. Intramuscular engraftments of ICG-labeled MSCs were clearly visualized by both PAI and NIRF over few days after transplantation in the hindlimb of healthy mice, suggesting that the proposed technique retains a considerable potential in the field of transplantation-focused research and therapy.
关键词： Indocyanine Green,Near Infrared Fluorescence Imaging,Photoacoustic Imaging,Cell tracking,Stem Cells
更新于2025-09-10 09:29:36
-
Fusing Near-Infrared Spectroscopy with Wearable Hemodynamic Measurements Improves Classification of Mental Stress
摘要： Human-computer interaction (HCI) technology, and the automatic classification of a person’s mental state, are of interest to multiple industries. In this work, the fusion of sensing modalities that monitor the oxygenation of the human prefrontal cortex (PFC) and cardiovascular physiology was evaluated to differentiate between rest, mental arithmetic and N-back memory tasks. A flexible headband to measure near-infrared spectroscopy (NIRS) for quantifying PFC oxygenation, and forehead photo-plethysmography (PPG) for assessing peripheral cardiovascular activity was designed. Physiological signals such as the electrocardiogram (ECG) and seismocardiogram (SCG) were collected, along with the measurements obtained using the headband. The setup was tested and validated with a total of 16 human subjects performing a series of arithmetic and N-back memory tasks. Features extracted were related to cardiac and peripheral sympathetic activity, vasomotor tone, pulse wave propagation, and oxygenation. Machine learning techniques were utilized to classify rest, arithmetic, and N-back tasks, using leave-one-subject-out cross validation. Macro-averaged accuracy of 85%, precision of 84%, recall rate of 83%, and F1 score of 80% were obtained from the classification of the three states. Statistical analyses on the subject-based results demonstrate that the fusion of NIRS and peripheral cardiovascular sensing significantly improves the accuracy, precision, recall, and F1 scores, compared to using NIRS sensing alone. Moreover, the fusion significantly improves the precision compared to peripheral cardiovascular sensing alone. The results of this work can be used in the future to design a multi-modal wearable sensing system for classifying mental state for applications such as acute stress detection.
关键词： wearable sensing,mental stress classification,near-infrared spectroscopy,Sensor fusion
更新于2025-09-10 09:29:36
-
Non-neuronal evoked and spontaneous hemodynamic changes in the anterior temporal region of the human head may lead to misinterpretations of functional near-infrared spectroscopy signals
摘要： Several functional near-infrared spectroscopy (fNIRS) studies report their findings based on changes of a single chromophore, usually concentration changes of oxygenated hemoglobin ([O2Hb]) or deoxygenated hemoglobin (HHb). However, influence of physiological actions may differ depending on which element is considered and the assumption that the chosen measure correlates with the neural response of interest might not hold. By assessing the correlation between [O2Hb] and [HHb] in task-evoked activity as well as resting-state data, we identified a spatial dependency of non-neuronal hemodynamic changes in the anterior temporal region of the human head. Our findings support the importance of reporting and discussing fNIRS outcomes obtained with both chromophores ([O2Hb] and [HHb]), in particular, for studies concerning the anterior temporal region of the human head. This practice should help to achieve a physiologically correct interpretation of the results when no measurements with short-distance channels are available while employing continuous-wave fNIRS systems.
关键词： superficial temporal vessels,temporal lobe,optical neuroimaging,temporalis muscle,scalp blood flow,extracerebral signal contamination,functional near-infrared spectroscopy
更新于2025-09-10 09:29:36
-
Rearrangeable and exchangeable optical module with system-on-chip for wearable functional near-infrared spectroscopy system
摘要： We developed a system-on-chip (SoC)-incorporated light-emitting diode (LED) and avalanche photo-diode (APD) modules to improve the usability and flexibility of a fiberless wearable functional near-infrared spectroscopy (fNIRS) system. The SoC has a microprocessing unit and programmable circuits. The time division method and the lock-in method were used for separately detecting signals from different positions and signals of different wavelengths, respectively. Each module autonomously works for this time-divided-lock-in measurement with a high sensitivity for haired regions. By supplying t3.3 V of power and base and data clocks, the LED module emits both 730- and 855-nm wavelengths of light, amplitudes of which are modulated in each lock-in frequency generated from the base clock, and the APD module provides the lock-in detected signals synchronizing with the data clock. The SoC provided many functions, including automatic-power-control of the LED, automatic judgment of detected power level, and automatic-gain-control of the programmable gain amplifier. The number and the arrangement of modules can be adaptively changed by connecting this exchangeable modules in a daisy chain and setting the parameters dependent on the probing position. Therefore, users can configure a variety of arrangements (single- or multidistance combinations) of them with this module-based system.
关键词： wearable,functional near-infrared spectroscopy,system-on-chip,module-based system
更新于2025-09-10 09:29:36