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MULTISPECTRAL IMAGING SYSTEM FOR QUANTITATIVE ASSESSMENT OF TRANSCUTANEOUS BLOOD OXYGEN SATURATION
摘要： This paper presents the use of Extended Modified Lambert Beer (EMLB) model for quantification of transcutaneous blood oxygen saturation (StO2) via a noninvasive approach. Continuous wave (CW) reflectance spectroscopy system is employed for measurement of intensity reflected from left index finger of an Asian nonsmoking volunteer at resting condition. Multispectral images captured in the wavelength range of 520 ? 600 nm at an interval of 10 nm are mathematically analyzed and fitted using the developed fitting algorithm to give the best estimation of StO2. The result from this preliminary study revealed a mean StO2 value of 75 ± 5% for the participating individual, which value agreed considerably well with that presented in previous works. This work concluded that the developed spectroscopy system and quantification technique can potentially be used as an alternative means to clinical assessment of wound healing progress.
关键词： Transcutaneous blood oxygen saturation,reflectance spectroscopy,Extended Modified Lambert Beer model,skin oximetry
更新于2025-09-11 14:15:04
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Redox Dynamics of Pd Supported on CeO <sub/>2</sub> -ZrO <sub/>2</sub> during Oxygen Storage/Release Cycles Analyzed by Time-Resolved <i>In Situ</i> Reflectance Spectroscopy
摘要： In situ time-resolved diffuse reflectance spectroscopy provided the redox dynamics of Pd nanoparticles supported on an oxygen storage material CeO2-ZrO2 (CZ) under lean/rich perturbation conditions. Because the reflectance at 450 nm is sensitive to the Pd oxidation state but is not affected by the redox of Ce3+/Ce4+ species of CZ, the real-time Pd redox can be monitored every second during oxygen storage/release in simulated engine combustion exhaust gas (CO–C3H6–NO–O2) corresponding to gasoline air-to-fuel ratios of 14.1 (rich) and 15.0 (lean). Although a large amount of O2 was stored by CZ upon the rich-to-lean switch, the rate of Pd oxidation during this event was found to be much more moderate compared to that with a reference catalyst, Pd/Al2O3. Because rapid oxygen uptake by CZ reduces the local O2 partial pressure near the surface, the oxidation of Pd should be retarded. This can preserve active metallic Pd and thus contribute to longer retention of high NO reduction efficiency even under the lean condition. However, the reduction of Pd oxide (PdO) upon reverse (lean-to-rich) switching occurred at a similar rate irrespective of the support material. The metallic Pd deposits near the interface with CZ promote the catalytic activation of reducing gases (CO and C3H6), resulting in significant oxygen release from CZ. The temperature dependence of the redox rate demonstrates that oxidation of metallic Pd to PdO is much slower than reduction over Pd/CZ, whereas oxidation is faster than reduction over Pd/Al2O3. The preservation of active metallic Pd under lean/rich perturbation conditions is another key role of the oxygen storage CZ co-catalyst.
关键词： CeO2-ZrO2,in situ diffuse reflectance spectroscopy,oxygen storage/release,redox dynamics,Pd nanoparticles
更新于2025-09-10 09:29:36
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Rapid and sensitive label-free determination of aflatoxin M1 levels in milk through a White Light Reflectance Spectroscopy immunosensor
摘要： Α miniaturized optical immunosensor based on White Light Reflectance Spectroscopy (WLRS) for the rapid and label-free detection of aflatoxin M1 (AFM1) in milk samples has been developed. WLRS sensing system consists of the measurement set-up and the biochip. The first encompasses the reflection probe, the light source and the spectrometer, while the latter is a Si chip with a SiO2 layer on top where an AFM1-bovine serum albumin conjugate has been immobilized. The assay was performed by running mixtures of rabbit polyclonal anti-AFM1 antibody with the calibrators or the samples, followed by reaction with biotinylated anti-rabbit IgG antibody and streptavidin. The assay cycle was completed in 25 min, the limit of detection was 6 pg/mL, and the linear working range extended from 0.012 to 2.0 ng/mL. The assay was repeatable (intra-and inter-assay coefficients of variation ranged from 2.1 to 6.3% and 3.5 to 8.2%, respectively) and accurate (percent recovery values ranged from 92.5 to 110%). AFM1 could be detected with the immunosensor developed in both processed and unprocessed milk of different animal species without any dilution. The excellent analytical characteristics and the small instrument size make the proposed sensor suitable for accurate low-cost AFM1 determination in milk samples at the point-of-need.
关键词： Aflatoxin M1,Immunosensor,Milk,White Light Reflectance Spectroscopy
更新于2025-09-10 09:29:36
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Surface-enhanced Raman spectroscopy (SERS) in cotton fabrics analysis
摘要： This article presents some aspects of application the dispersive Micro-Raman Spectroscopy in textile fibers analysis. Research were dedicated to the methodology of surface enhancement Raman spectroscopy (SERS) studies on cotton fabric and possibility of its application in fibers characterization. Studies were carried out on dyed cotton fabrics modified by silver nanowires (AgNWs). Three reactive dyes (blue, yellow, red) and four color intensities (0.5%, 1%, 2% and 5%) were used. AgNWs colloid was deposited on undyed and dyed cotton fabrics by dipping and drying method. Dyed fabrics were examined by spectroscopic methods: FTIR ATR, Raman, UV-Vis Diffuse Reflectance Spectroscopy, Fluorescence Spectroscopy. Raman signal enhancement phenomena occurring on the silver nanoparticles increases the possibility of fiber and dye identification especially in the case of dyes used in cotton dyeing reveals fluorescence.
关键词： UV-Vis Diffuse Reflectance Spectroscopy,SERS,Fluorescence Spectroscopy,reactive dyes,FTIR ATR,Micro-Raman spectroscopy,Cotton fibers
更新于2025-09-09 09:28:46
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Reflectance spectroscopy of ammonium-bearing phyllosilicates
摘要： The identification of NH4-bearing phyllosilicates on Ceres poses the question on the NH4-carrier phase(s) and in this study we describe the laboratory production and IR spectroscopic measurements of a suite of ten NH4-phyllosilicates, starting from the corresponding NH4-free minerals. For each mineral, we prepared three types of powder samples: raw (R), ammoniated (A), and leached (L). All samples have been spectrally characterized by means of visible/infrared spectroscopy in the INAF-IAPS laboratories with the FieldSpec Pro in the 0.35-2.5 μm range, and with the FT-IR, using a Vertex 80 spectrometer operating in the range of 2 to 14 μm. The samples were also measured with the SPectral IMager, an imaging spectrometer operating in the spectral range 0.2 – 5.1 μm, which is a replica of the VIR spectrometer on-board Dawn spacecraft. Reflectance spectra of the ammoniated clays show bands near 1.56 μm, 2.05 μm, 2.12 μm, 3.06 μm, 3.25 μm, 3.55 μm, 4.2 μm, 5.7 μm and 7.0 μm that are related to the presence of nitrogen complexes. Treatment of phyllosilicates with ammonia shows that different minerals behave in different ways: NH4+ ions are easily accepted by the smectites, while other non-expandable structures do not accept these ions. The obtained results can be used to better constrain the NH4-bearing species present on Ceres and, possibly, other bodies of the solar system.
关键词： Reflectance spectroscopy,smectites,VIS-NIR spectroscopy,Ceres,ammonium-bearing phyllosilicates
更新于2025-09-09 09:28:46
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Determination of Nitrogen Concentration in Fresh Pear Leaves by Visible/Near-Infrared Reflectance Spectroscopy
摘要： A rapid and reliable method is required to determine the N status of pear (Pyrus communis L.) leaves during the growing season for timely fertilization to improve the yields and fruit quality. In the present study, we evaluated visible and near-infrared reflectance (Vis/NIR) spectra of fresh pear leaves using partial least squares (PLS) regression to determine the N concentration of fresh pear leaves. In addition, we studied the performance of modified spectra generated using different preprocessing techniques. A total of 450 leaf samples were collected from 6-yr-old pear trees of two cultivars, and randomly separated into two subsets (calibration subset [294 samples] and validation subset [180 samples]) after excluding outliers by using principle component analysis. Results showed that the model built using full spectra performed better than that developed using characteristic wavelength segments. In addition, we found that original spectral proved to provide better accuracy than derivative spectra. Among the studied preprocessing techniques, moving average smoothing (MAS) technique improved accuracy the most. Overall results suggested that PLS regression with preprocessing of full spectra using MAS is optimal method for modeling N concentration of fresh pear leaves which yielded 0.961 and 0.953 coefficient of determination (R2) for calibration and cross-validation, respectively. The validation of this method resulted high R2 value (0.847) and low mean relative error (4.48%). In conclusion, this model could provide a rapid and more reliable method to determine the total N concentration in fresh pear leaves and could be useful for fertilization management in pear orchards.
关键词： partial least squares regression,preprocessing techniques,pear leaves,Nitrogen concentration,visible/near-infrared reflectance spectroscopy
更新于2025-09-09 09:28:46