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Applicability of near infrared spectroscopy for real-time soil detection during automatic dishwashing
摘要： The purpose of this study was to utilize NIR spectrometry to develop a novel method to detect and determine concentrations of different soils in dishwashing liquor during automatic dishwashing in real-time. If it is possible to differentiate between soils, this could be an opportunity to react specifically to them (e.g. by increasing the water temperature if fat components are not sufficiently emulsifying). The possibility of an automatic adaptation of the dishwashing process to different soils and soil levels could lead to a shorter, more environmentally friendly and cost-reducing process. In a first approach, an emulsion containing three soil types (oatmeal, egg-yolk and butterfat), water and detergent were used to develop NIR spectrometry prediction models. Transmittance spectra obtained with an Fourier transform near infrared (FT-NIR) spectrometer of testing standards of 76 automatic dishwashing cycles with seven samples per cycle were taken at various times during the main washing process for calibration (and validation) of the NIR spectrometry prediction models. The spectra were pretreated to develop NIR spectrometry prediction models for each type of soil using the partial least squares regression method with cross-validation. Overall, the coefficients of determination in cross-validation are R2 > 0.92 for all NIR spectrometry prediction models developed. The results of the prediction models developed show that NIR spectrometry technology is a promising method to predict different levels of predefined soils in dishwashing liquor. The NIR spectrometry models were applied to an automatic dishwashing process with soiled dishes instead of emulsions containing soils to test their applicability. The resulting dishwashing process could be tracked in real-time by the dissolved soil concentrations, observed in the dishwashing liquor.
关键词： dishwasher,validation,sensor,emulsion,calibration,homogenization,soil,Near infrared spectroscopy
更新于2025-09-23 15:22:29
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Predicting Mechanical Strength of In-Use Firefighter Protective Clothing Using Near-Infrared Spectroscopy
摘要： The exact lifespan of in-use firefighter protective clothing is difficult to predict due to the large variations in use between individual garments. Furthermore, testing methods used to evaluate new protective clothing are destructive in nature and could not be applied to in-use garments. Various non-destructive techniques have been proposed for the evaluation of in-use clothing, each possessing its own advantages and disadvantages. The ability of near-infrared spectroscopy to predict the tensile strength of thermally aged fabrics used in protective clothing for wildland firefighters and other workers is investigated here. Fabrics were exposed to heat fluxes from 10 kW/m2 to 40 kW/m2 for various durations using the cone calorimeter, after which the tensile strength of the fabrics was measured. Temperatures measured during the exposures and results of thermal gravimetric analysis tests were used to interpret changes in tensile strength. Multivariate linear regression was used to develop correlations between the tensile strength and the reflectance values measured between 1500 nm and 2500 nm for new and thermally aged fabrics. It was found that models based on reflectance measurements made at as few as three wavelengths could be used to estimate the tensile strength of the thermally aged specimens.
关键词： Thermal ageing,Near-infrared spectroscopy,Firefighter,Durability,Non-destructive testing,Protective clothing
更新于2025-09-23 15:22:29
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Associations of Perioperative Renal Oximetry Via Near-Infrared Spectroscopy, Urinary Biomarkers, and Postoperative Acute Kidney Injury in Infants After Congenital Heart Surgery
摘要： Objectives: Examine the relationship between perioperative renal regional tissue oximetry, urinary biomarkers, and acute kidney injury in infants after congenital cardiac surgery with cardiopulmonary bypass. Design: Prospective, observational. Setting: Cardiac operating room and cardiac ICU. Patients: Neonates and infants without history of kidney injury or anatomic renal abnormality. Interventions: None. Measurements and Main Results: Renal regional tissue oximetry was measured intraoperatively and for 48 hours postoperatively. Urinary levels of neutrophil gelatinase-associated lipocalin and tissue inhibitor of metalloproteinases 2 together with insulin-like growth factor-binding protein 7 were measured preoperatively, 2, 12, and 24 hours postoperatively. Patients were categorized as no acute kidney injury, stage 1, or Stage 2–3 acute kidney injury using the Kidney Disease: Improving Global Outcomes criteria with 43 of 70 (61%) meeting criteria for any stage acute kidney injury. Stage 2–3 acute kidney injury patients had higher tissue inhibitor of metalloproteinases 2, insulin-like growth factor-binding protein 7 at 2 hours (0.3 vs 0.14 for stage 1 acute kidney injury and 0.05 for no acute kidney injury; p = 0.052) and 24 hours postoperatively (1.71 vs 0.27 for stage 1 acute kidney injury and 0.19 for no acute kidney injury, p = 0.027) and higher neutrophil gelatinase-associated lipocalin levels at 24 hours postoperatively (10.3 vs 3.4 for stage 1 acute kidney injury and 6.2 for no acute kidney injury, p = 0.019). Stage 2–3 acute kidney injury patients had lower mean cardiac ICU renal regional tissue oximetry (66% vs 79% for stage 1 acute kidney injury and 84% for no acute kidney injury, p = 0.038). Regression analyses showed that tissue inhibitor of metalloproteinases 2, insulin-like growth factor-binding protein 7 at 2 hours postoperatively and nadir intraoperative renal regional tissue oximetry to be independent predictors of postoperative kidney damage as measured by urinary neutrophil gelatinase-associated lipocalin. Conclusions: We observed modest differences in perioperative renal regional tissue oximetry and urinary biomarker levels compared between acute kidney injury groups classified by creatinine-dependent Kidney Disease: Improving Global Outcomes criteria, but there were significant correlations between renal regional tissue oximetry, tissue inhibitor of metalloproteinases 2, insulin-like growth factor-binding protein 7, and postoperative neutrophil gelatinase-associated lipocalin levels. Kidney injury after infant cardiac surgery may be undetectable by functional assessment (creatinine) alone, and continuous monitoring of renal regional tissue oximetry may be more sensitive to important subclinical acute kidney injury.
关键词： near-infrared spectroscopy,infant,biomarker,congenital heart surgery,cardiac intensive care unit,acute kidney injury
更新于2025-09-23 15:22:29
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Low Renal Oxygen Saturation at Near-Infrared Spectroscopy on the First Day of Life Is Associated with Developing Acute Kidney Injury in Very Preterm Infants
摘要： Background: Acute kidney injury (AKI) is a frequent complication in preterm infants, and the identification of early markers of renal hypoperfusion is a chief challenge in neonatal intensive care units. Objectives: To describe the association between early markers of cardiovascular function and renal perfusion with AKI occurrence in a cohort of preterm infants < 32 weeks’ gestation. Methods: 128 infants were prospectively included from birth to discharge. During the first day of life, we assessed cardiovascular function, systemic and organ blood flow by Doppler ultrasound, and monitored cerebral and renal regional oxygen saturation (rSO2) using near-infrared spectroscopy (NIRS). These measures were analyzed in relation to developing AKI and serum creatinine (SCr) peak from day 2 to 7 of life. Results: 12 of 128 infants presented with AKI (9.4%). SCr peak was 155.3 ± 30.2 μmol/L in infants with AKI versus 82.0 ± 16.5 in non-AKI infants (p < 0.001). Among all measures of cardiovascular function and renal perfusion, low mean cerebral and renal rSO2 during the first day of life and a low resistive index at renal artery Doppler were significantly associated with developing AKI. After adjustment for possible confounding factors, low renal rSO2 on the first day of life remained associated with a high SCr peak from day 2 to 7 of life. Conclusion: Low renal rSO2 values during the first day of life correlate with developing AKI in preterm infants < 32 weeks’ gestation. NIRS monitoring of renal function during adaptation seems promising, and its very early use after birth to detect kidney hemodynamic dysfunction deserves further investigations.
关键词： Acute renal failure,Neonatal intensive care,Postnatal adaptation,Near-infrared spectroscopy,Renal function,Extremely low-birth-weight infants,Renal hemodynamics,Premature newborns,Patent ductus arteriosus
更新于2025-09-23 15:22:29
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Perspective: Prospects of non-invasive sensing of the human brain with diffuse optical imaging
摘要： Since the initial demonstration of near-infrared spectroscopy (NIRS) for noninvasive measurements of brain perfusion and metabolism in the 1970s, and its application to functional brain studies (fNIRS) in the 1990s, the field of noninvasive optical studies of the brain has been continuously growing. Technological developments, data analysis advances, and novel areas of application keep advancing the field. In this article, we provide a view of the state of the field of cerebral NIRS, starting with a brief historical introduction and a description of the information content of the NIRS signal. We argue that NIRS and fNIRS studies should always report data of both oxy- and deoxyhemoglobin concentrations in brain tissue, as they complement each other to provide more complete functional and physiological information, and may help identify different types of confounds. One significant challenge is the assessment of absolute tissue properties, be them optical or physiological, so that relative measurements account for the vast majority of NIRS and fNIRS applications. However, even relative measurements of hemodynamics or metabolic changes face the major problem of a potential contamination from extracerebral tissue layers. Accounting for extracerebral contributions to fNIRS signals is one of the most critical barriers in the field. We present some of the approaches that were proposed to tackle this challenge in the study of cerebral hemodynamics and functional connectivity. Finally, we critically compare fNIRS and functional magnetic resonance imaging by relating their measurements in terms of signal and noise, and by commenting on their complementarity.
关键词： hemodynamics,functional connectivity,functional magnetic resonance imaging,human brain,near-infrared spectroscopy,diffuse optical imaging,non-invasive sensing,functional near-infrared spectroscopy
更新于2025-09-23 15:21:21
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Muscle oxygenation dynamics in response to electrical stimulation as measured with near-infrared spectroscopy: A pilot study
摘要： Neuromuscular electrical stimulation (NMES) is used for preventing muscle atrophy and improving muscle strength in patients and healthy people. However, the current intensity of NMES is usually set at a level that causes the stimulated muscles to contract. This typically causes pain. Quantifying the instantaneous changes in muscle microcirculation and metabolism during NMES before muscle contraction occurs is crucial, because it enables the current intensity to be optimally tuned, thereby reducing the NMES-induced muscle pain and fatigue. We applied near-infrared spectroscopy (NIRS) to measure instantaneous and deoxygenation changes in 43 healthy young adults during NMES at 10, 15, 20, 25, 30, and 35 mA. Having been stabilized at the NIRS signal baseline, total hemoglobin concentration increased immediately after stimulation in a dose-dependent manner (p < 0.05) until stimulation was stopped at the level causing muscle contraction without pain. Tissue deoxygenation appeared relatively unchanged during NMES. We conclude that NIRS can be used to determine the optimal NMES current intensity by monitoring oxygenation changes.
关键词： Muscle oxygenation dynamics,near-infrared spectroscopy,tissue optics,neuromuscular electrical stimulation
更新于2025-09-23 15:21:21
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Identification of Hybrid Okra Seeds Based on Near-Infrared Hyperspectral Imaging Technology
摘要： Near-infrared (874–1734 nm) hyperspectral imaging technology combined with chemometrics was used to identify parental and hybrid okra seeds. A total of 1740 okra seeds of three different varieties, which contained the male parent xiaolusi, the female parent xianzhi, and the hybrid seed penzai, were collected, and all of the samples were randomly divided into the calibration set and the prediction set in a ratio of 2:1. Principal component analysis (PCA) was applied to explore the separability of different seeds based on the spectral characteristics of okra seeds. Fourteen and 86 characteristic wavelengths were extracted by using the successive projection algorithm (SPA) and competitive adaptive reweighted sampling (CARS), respectively. Another 14 characteristic wavelengths were extracted by using CARS combined with SPA. Partial least squares discriminant analysis (PLS-DA) and support vector machine (SVM) were developed based on the characteristic wavelength and full-band spectroscopy. The experimental results showed that the SVM discriminant model worked well and that the correct recognition rate was over 93.62% based on full-band spectroscopy. As for the discriminative model that was based on characteristic wavelength, the SVM model based on the CARS algorithm was better than the other two models. Combining the CARS+SVM calibration model and image processing technology, a pseudo-color map of sample prediction was generated, which could intuitively identify the species of okra seeds. The whole process provided a new idea for agricultural breeding in the rapid screening and identi?cation of hybrid okra seeds.
关键词： hybrid okra seeds,chemometrics,seed classification,near-infrared spectroscopy
更新于2025-09-23 15:21:01
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Construction of global and robust near-infrared calibration models based on hybrid calibration sets using Partial Least Squares (PLS) regression
摘要： Near-infrared spectroscopy (NIR) models built on a particular instrument are often invalid on other instruments due to spectral inconsistencies between the instruments. In the present work, global and robust NIR calibration models were constructed by partial least square (PLS) regression based on hybrid calibration sets, which are composed of both primary and secondary spectra. Three datasets were used as case studies. The first consisted of 72 radix scutellaria samples measured on two NIR spectrometers with known baicalin content. The second was composed of 80 corn samples measured on two instruments with known moisture, oil, and protein concentrations. The third dataset included 279 primary samples of tobacco with known nicotine content and 78 secondary samples of tobacco with known nicotine concentrations. The effect of the number of secondary spectra in the hybrid calibration sets and the methods for selecting secondary spectra on the PLS model performance were investigated by comparing the results obtained from different calibration sets. This study shows that the global and robust calibration models accurately predicted both primary and secondary samples as long as the ratios of the number of primary spectra to the number of secondary spectra were less than 22. The models performance was not influenced by the selection method of the secondary spectra. The hybrid calibration sets included the primary spectral information and also the secondary spectra; rendering the constructed global and robust models applicable to both primary and secondary instruments.
关键词： global and robust models,hybrid calibration set,Near-infrared spectroscopy,partial least squares (PLS) regression
更新于2025-09-23 15:21:01
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Variable selection for the determination of total polar materials in fried oils by near infrared spectroscopy
摘要： Total polar materials (TPM) content is considered as the best indicator and the most common parameter to check the quality of deep-frying oils. The development of simpler and quicker analytical techniques than the available methods to monitor oil quality in restaurants and fried food outlets is an important topic related to the human health. This paper reports a comparison of the variable selection of near infrared (NIR) spectra by multiple linear regression (MLR-NIR) with partial least squares (PLS-NIR) models for the quantification of TPM in fried vegetable oils. The use of PLS-NIR offers an alternative in laboratory bench equipment for the determination of TPM in oils employed for frying different kinds of foods with relative prediction errors of 6.5%, a coefficient of determination for prediction of 0.99 and a residual predictive deviation (RPD) of 9.2 when selected wavenumber intervals were employed. MLR-NIR allows the selection of a reduced number of wavenumber in order to develop low cost instruments to evaluate the frying oil quality. Based on the NIR signals at four wavenumbers, the relative prediction error was 12.1%, the coefficient of determination for prediction was 0.96 and the RPD was 5.0.
关键词： partial least squares,total polar materials,multiple linear regression,vegetable fried oils,Near infrared spectroscopy
更新于2025-09-23 15:21:01
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Comparative identification of citrus huanglongbing by analyzing leaves using laser-induced breakdown spectroscopy and near-infrared spectroscopy
摘要： In this work, laser-induced breakdown spectroscopy (LIBS), near-infrared spectroscopy (NIR), and LIBS joint NIR (LIBS–NIR) were investigated for the identification of citrus huanglongbing (HLB). The content of minerals like calcium (Ca), zinc (Zn), and potassium (K) was obtained by atomic absorption spectroscopy (AAS). The spectra of LIBS, NIR, and LIBS–NIR were operated by discriminating analysis (DA) and multi-layer perception (MLP). The results of AAS and Kolmogorov–Smirnov Test (K–S test) showed that the Ca and Zn decreased significantly in HLB infected leaves, but K is not significantly influence by HLB. The LIBS–NIR combining with MLP-PCA had highest diagnostic accuracy of 89.5% and 95.7% in training and test set, respectively. These results proved that joint spectrum of LIBS–NIR is a feasible method to identify citrus HLB.
关键词： laser-induced breakdown spectroscopy,minerals,identification,citrus huanglongbing,near-infrared spectroscopy
更新于2025-09-23 15:19:57