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Residue-Specific Conformational Heterogeneity of Proline-Rich Sequences Uncovered via Infrared Spectroscopy
摘要： Conformational heterogeneity is critical to understanding protein function but challenging to quantify. Experimental approaches that can provide sufficient temporal and spatial resolution to measure even rapidly interconverting states at specific locations in proteins are needed to fully elucidate the contribution of conformational heterogeneity and dynamics to function. Infrared spectroscopy in combination with the introduction of carbon deuterium bonds, which provide frequency-resolved probes of their environments, can uncover rapidly interconverting states with residue-specific detail. Using this approach, we quantify conformational heterogeneity of proline-rich peptides associated with different proline backbone conformations, as well as reveal their dependence on the sequence context.
关键词： Carbon deuterium bonds,Protein function,Infrared spectroscopy,Proline-rich sequences,Conformational heterogeneity
更新于2025-09-10 09:29:36
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Comparative Quantification of Arterial Lipid by Intravascular Photoacoustic-Ultrasound Imaging and Near-Infrared Spectroscopy-Intravascular Ultrasound
摘要： Intravascular photoacoustic-ultrasound (IVPA-US) imaging and near-infrared spectroscopy-intravascular ultrasound (NIRS-IVUS) are two hybrid modalities that detect arterial lipid, with comparison necessary to understand the relative advantages of each. We performed in vivo and ex vivo IVPA-US imaging of the iliac arteries of Ossabaw swine with metabolic syndrome (MetS) and lean swine to investigate sensitivity for early-stage atherosclerosis. We repeated imaging ex vivo with NIRS-IVUS for comparison to IVPA-US and histology. Both modalities showed significantly greater lipid in MetS vs. lean swine, but only IVPA-US localized the lipid as perivascular. To investigate late-stage atherosclerosis, we performed ex vivo IVPA-US imaging of a human coronary artery with comparison to NIRS-IVUS and histology. Two advanced fibroatheromas were identified, with agreement between IVPA-measured lipid area and NIRS-derived lipid content. As confirmed histologically, IVPA-US has sensitivity to detect lipid content similar to NIRS-IVUS and provides additional depth resolution, enabling quantification and localization of lipid cores within plaques.
关键词： Swine,Lipid core plaque,Near-infrared spectroscopy,Human,Intravascular imaging,Photoacoustic imaging,Atherosclerosis,Perivascular adipose tissue
更新于2025-09-10 09:29:36
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Neuroergonomics || Functional Near-Infrared Spectroscopy
摘要： The mission of social psychology is to understand “how the thoughts, feelings, and behaviour of individuals are influenced by the actual, imagined, or implied presence of others.” The mission of social neuroscience is to understand the neural and broader biological underpinnings of social psychological phenomena. Like every scientific discipline, the success of social neuroscience rests on the effectiveness of its methods. Recent years have witnessed a proliferation of methods that hold promise for advancing social neuroscience. One such method is continuous-wave functional near-infrared spectroscopy (fNIRS), a functional neuroimaging technique that can be used to measure brain activity noninvasively. In this chapter we demonstrate the utility of fNIRS for social neuroscience in identifying well-established patterns of prefrontal activity when people make self- and other-referential judgments.
关键词： social neuroscience,self-referential judgments,prefrontal activity,functional near-infrared spectroscopy,fNIRS
更新于2025-09-10 09:29:36
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Recent quantitative research of near infrared spectroscopy in traditional Chinese medicine analysis
摘要： Traditional Chinese medicines (TCMs) have been used in China to prevent and cure diseases for centuries. Due to the complexity of TCMs, fast and highly efficient techniques are required to develop their quality control. Near infrared spectroscopy (NIRS) has been widely applied in TCM analysis for both nonpolar and polar components. This review describes an overview of experimental conditions (spectra pretreatments and multivariate techniques) investigated in NIRS for TCM components that are related to individual compounds such as lipids, essential oils, phenolics, alkaloids, saponins and carbohydrates. Their potential in the separation of TCMs using relevant applications with a particular focus on quantitative analysis is also demonstrated.
关键词： traditional Chinese medicine,quantitative analysis,Near infrared spectroscopy
更新于2025-09-10 09:29:36
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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
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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
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Raman, Infrared, and Chemical Characterization of Fly Ash-Generated Spherules
摘要： The majority of studies on silicate glass spherules containing fly ash deal only with the determination of their chemical composition. Nearly 70 vol.% of fly ash is comprised of silicate glass spherules. Here, we report spectroscopic properties of silicate glass spherules using the laser micro-Raman and Fourier transform infrared techniques coupled with refractive index measurements, X-ray diffraction, and electron probe micro-analysis to better ascertain their physical and chemical properties. Glass spherules show similar refractive indices (1.499–1.510) and a bell-shaped diffraction pattern with 5–10 vol.% of crystallites observed on microscopic and submicroscopic scales. The bulk chemical composition of fly ash spherules is predominantly silica-rich (SiO2: 70.96–74.13 wt.%) with a subordinate amount of Al2O3 (0.11–0.69 wt.%), FeO(Total) + MgO (3.6–4.94 wt.%), and CaO + Na2O + K2O (20.83–22.62 wt.%). The infrared spectra suggest the presence of a dissolved –OH– bearing fluid phase in the studied fly ash spherules. The spectra also show symmetric stretching peaks of C–O–C due to the atmospheric CO2 adsorption at 2350 cm–1. The Raman spectra show broad amorphous and/or short-ordered phases.
关键词： fly ash,micro-chemical analysis,Raman and infrared spectroscopy,silicate glass spherules
更新于2025-09-10 09:29:36
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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
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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
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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