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Preliminary Study on the Determination of ppm-Level Concentration of Histamine in Tuna Fish Using a Dry Extract System for Infrared Coupled with Near-Infrared Spectroscopy
摘要： Rapid and simple methods to determine histamine in tuna fish have been examined. A dry extract system for infrared (DESIR) was coupled with near-infrared spectroscopy in order to obtain the absorption of histamine in tuna fish at the ppm level. The result showed that the optimal extraction solvent for preparing DESIR samples was 75% methanol and boiling water (100 °C). Calibration equations were developed and tested by independent validation set samples. The calibration equation developed from boiling water as solvent extraction was slightly better than the equation developed from 75% methanol solvent with a coefficient of determination (R2) of 0.79, a standard error of calibration of 2.45 ppm, a standard error of prediction of 2.94 ppm, and a bias of 0.10 ppm. Furthermore, the predicted values from both equations were not significantly different from the reference values obtained from the standard method at the 95% confidence interval. Compared to the current AOAC fluorometric official method, the proposed technique simplified and reduced the preparation time.
关键词： rapid method,histamine,near-infrared spectroscopy,DESIR,tuna fish
更新于2025-09-12 10:27:22
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An approach for correcting optical paths of different wavelength lasers in diffusive medium based on Monte Carlo simulation
摘要： Near-infrared spectroscopy (NIRS) generally uses multiple wavelengths of light to obtain functional information. When different wavelengths are employed together, their optical paths are different in the medium and it can potentially cause errors. In this study, we introduced an approach of correcting optical paths when laser sources are used. Laser can be approximated by a point source in a diffusive medium and its depth depends on the wavelength. By multiplying the ratio of detected weights emitted from different point sources, they are conceptually moved to the same position. Monte Carlo simulation was implemented to accumulate required data. As an example for verifying this method, optical properties of the white matter of the brain was used. All combinations of four wavelengths (400, 550, 700, and 850 nm) and six source-detector distances (0.5 mm to 3.0 mm at intervals of 0.5 mm) were simulated. Under the same example conditions, the difference between the simulation results and this method was about ‘1.28%’. The results showed that this approach is applicable to short source-detector distance conditions.
关键词： Monte Carlo simulation,Point source approximation,Near infrared spectroscopy,Light diffusion,Optical path,Penetration depth
更新于2025-09-12 10:27:22
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Multimodal Laser Stimulation and Traditional Needle Acupuncture in Post-Stroke Patients—A Pilot Cross-Over Study with Results from Near Infrared Spectroscopy
摘要： Background: The objective of this pilot study was to evaluate the cerebral e?ects of laser stimulation and traditional needle acupuncture in patients after stroke. Methods: Seventeen stroke patients (12 female and ?ve male; mean age ± SD: 66.5 ± 12.9 years) were randomly selected in a stroke rehabilitation hospital. Patients’ regional cerebral blood oxygen saturation (rSO2) values were recorded before, during, and after needle acupuncture (scalp, ear and body) as well as before, during, and after corresponding laser stimulation (red laser, four points: 100 mW, 658 nm, 500 μm; yellow laser, one point: 50 mW, 589 nm, 500 μm; infrared laser, three points: 100 mW, 810 nm, 500 μm; green laser, one point: 5 mW, 532 nm, 500 μm) in a cross-over study design. Results: There were no signi?cant changes after needle acupuncture in the phases immediately after needle insertion or during acupuncture stimulation. However, after manual needle acupuncture and after laser stimulation, the majority of the rSO2 values showed increases. The highest value (+3%) was reached after laser stimulation treatment. Heart rate and blood pressure before and after the treatments did not show signi?cant alterations. Conclusions: Changes in local cerebral oxygen saturation could be quanti?ed, although con?rmation may only be expected after extensive follow-up studies.
关键词： near infrared spectroscopy,stroke,laser stimulation,scalp acupuncture,body acupuncture,ear acupuncture,acupuncture
更新于2025-09-12 10:27:22
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Feasibility study for rapid near-infrared spectroscopic identification of different gallbladder diseases by direct analysis of bile juice
摘要： A whole-sample-covering near-infrared (NIR) spectroscopy scheme has been adopted for the simple drop-and-dry measurement of raw bile juice for the identification of gallbladder (GB) diseases of stone, polyp, and cancer. For reproducible measurement, a non-NIR absorbing polytetrafluoroethylene (PTFE) providing a hydrophobic surface was chosen as a substrate to form bile juice droplets of a consistent shape. To ensure representative spectroscopic sampling, NIR radiation illuminated the whole area of the dried sample for spectral acquisition. The NIR band shapes and relative band intensities of GB cancer differed moderately from those of GB stone and GB polyp. The composition of GB cancer samples was presumed to be dissimilar from other sample compositions. Differentiation between GB polyp and GB stone, however, was less facile; nevertheless, in the case of GB polyp samples, the obtained NIR features were informative in the identification of various pathological conditions such as adenomyomatosis (abnormal growth of epidermal tissue) and hepatitis B. To elucidate the NIR features of bile juice samples, separate NIR spectra of major bile constituents such as conjugated bile salts, lecithin, cholesterol, and albumin were analyzed. The demonstrated NIR spectroscopy scheme requiring no sample pretreatment or separation of bile juice could be useful for fast bile juice-based screening of GB diseases, especially the identification of early GB cancer.
关键词： gallbladder diseases,bile juice,drop-and-dry measurement,PTFE substrate,near-infrared spectroscopy
更新于2025-09-12 10:27:22
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Soil organic carbon predictions in Subarctic Greenland by visible–near infrared spectroscopy
摘要： Release of carbon from high-latitude soils to the atmosphere may have significant effects on Earth’s climate. In this contribution, we evaluate visible–near-infrared spectroscopy (vis-NIRS) as a time- and cost-efficient tool for assessing soil organic carbon (SOC) concentrations in South Greenland. Soil samples were collected at two sites and analyzed with vis-NIRS. We used partial least square regression (PLS-R) modeling to predict SOC from vis-NIRS spectra referenced against in situ dry combustion measurements. The ability of our approach was validated in three setups: (1) calibration and validation data sets from the same location, (2) calibration and validation data sets from different locations, and (3) the same setup as in (2) with the calibration model enlarged with few samples from the opposite target area. Vis-NIRS predictions were successful in setup 1 (R2 = 0.95, root mean square error of prediction [RMSEP] = 1.80 percent and R2 = 0.82, RMSEP = 0.64 percent). Predictions in setup 2 had higher errors (R2 = 0.90, RMSEP = 7.13 percent and R2 = 0.78, RMSEP = 2.82 percent). In setup 3, the results were again improved (R2 = 0.95, RMSEP = 2.03 percent and R2 = 0.77, RMSEP = 2.14 percent). We conclude that vis-NIRS can obtain good results predicting SOC concentrations across two subarctic ecosystems, when the calibration models are augmented with few samples from the target site. Future efforts should be made toward determination of SOC stocks to constrain soil–atmosphere carbon exchange.
关键词： visible–near-infrared spectroscopy,subarctic,Soil organic carbon,Greenland
更新于2025-09-12 10:27:22
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Improvement of teaching near-infrared spectroscopic analysis for undergraduates
摘要： With the growing acceptance and expansion of near-infrared spectroscopy as a potential tool in chemical research and industrial quality and process control, it has also become an academic challenge for University teachers, to teach students the necessary theoretical and instrumental principles of this spectroscopic technique. Using the elective open experiment courses and carefully designing their scientific content can produce a double teaching effect; students participate in discipline competitions under careful guidance by teachers, and they can achieve particularly good results; graduation thesis is another way to improve the ability of students in learning and comprehending the near-infrared technology. Years of practical experience have proven that the above approaches are feasible.
关键词： teaching,Near-infrared spectroscopy,undergraduates
更新于2025-09-11 14:15:04
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Classification of saline water for irrigated agriculture using near infrared spectroscopy coupled with pattern recognition techniques
摘要： This research aimed to create near infrared (NIR) spectroscopy models for the classification of saline water with a pattern recognition technique. A total of 112 water samples were collected from the Tha Chin river basin in Thailand. Water samples with salinity less than 0.2 g/l were identified as suitable for agriculture, while water samples with salinity higher than 0.2 g/l were found to be unsuitable. The NIR spectra of water samples were recorded using a Fourier transform (FT) NIR spectrometer in the wavenumber of 12,500–4,000 cm-1. The salinity of each water sample was analysed by electrical conductivity meter. Identification models were established with 5 supervised pattern recognition techniques including k-nearest neighbour (k-NN), support vector machine (SVM), artificial neural network (ANN), soft independent modelling of class analogies (SIMCA), and partial least squares-discriminant analysis (PLS-DA). The performance of the NIR model was carried out with a split-test method. About 80% of spectra (90 spectra) were randomly selected to develop the classification models. After model development, the NIR spectroscopy models were used to classify the categories of the remaining samples (22 samples). The ANN model showed the highest performance for classifying saline water with precision, recall, F-measure and accuracy of 84.6%, 100.0%, 91.7% and 90.9%, respectively. Other techniques presented satisfactory classification results with accuracy greater than 68.2%. This point indicated that NIR spectroscopy coupled with the pattern recognition technique could be applied to classify saline water for agricultural use according to salinity level in natural resources.
关键词： pattern recognition,near infrared spectroscopy,agriculture,saline water
更新于2025-09-11 14:15:04
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Wearable SiPM-based NIRS Interface Integrated with Pulsed Laser Source
摘要： We present the design of a miniaturized probe integrating silicon photomultiplier and light-pulsing electronics in a single 2x2mm2 CMOS chip which includes functional blocks such as a fast pulse-laser driver and synchronized single-photon detection circuit. The photon pulses can be either counted on-chip or processed by an external high-speed electronic module such as time-corelated single photon counting (TCSPC) unit. The integrated circuit was assembled on a printed circuit board (PCB) and also on a 2.5D silicon interposer platform of size 1 cm and interfaced with a silicon photomultiplier (SiPM), vertical cavity surface emitting laser (VCSEL) and other ancillary components such as capacitors and resistors. Our approach of integrating an optical interface to optimize light collection on the small active area and light emission from the vertical-cavity surface-emitting laser (VSCEL) will facilitate clinical adoption in many applications and change the landscape of Near Infrared Spectroscopy (NIRS) hardware commercially due to significant optode-size reduction and the elimination of optical fibers.
关键词： Near-Infrared Spectroscopy (NIRS),Time-Domain (TD),complementary metal-oxide-semiconductor (CMOS),Vertical Cavity Surface Emitting Laser (VCSEL),Silicon Photomultiplier (SiPM),Optical Probe
更新于2025-09-11 14:15:04
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Near-Infrared Fieldoscopy of Water
摘要： Linear near-infrared (NIR) spectroscopy provides information on the molecular composition, structure, and conformation, affording remarkable potential for high-resolution, in-depth, label-free biological spectro-microscopy. Broadband measurements in NIR have been carried out in the frequency domain. However, in this approach, the detection of small absorption differences is limited to the intensity noise of the source, and the detection dynamic range. We propose the concept of molecular fieldoscopy to alleviate above-mentioned limitations. Here, phase-coherent, broadband ultrashort pulse in NIR range excites molecules, afterward the transmitted electric field that carries the molecular response is directly detected by electro-optics sampling (EOS). The excitation pulse has tens of femtoseconds temporal duration, which is considerably shorter than free induction decay (FID) of the molecules under inspection. Therefore, the excitation pulse is temporally separated from the molecular response, allowing background-free measurement, and suppressing the influence of the intensity noise of the source. Moreover, measuring the complex electric field permits for extracting the full spectral phase information of the molecular response, adding a new dimension to the obtained spectroscopic data. In this work, we report about field-resolved overtone spectroscopy of water molecules in the liquid phase by using EOS to detect its first overtone vibrational mode of O-H bond appearing at 1900-1950 nm. In this respect, a carrier-envelope phase (CEP) stable, ultra-broadband spectrum covering from 700 nm to 2500 nm was directly generated from a home-built, diode-pumped Yb:YAG thin-disk regenerative amplifier. The broadband spectrum was splitted into two spectral regions: i) spectral region covering 700-1400 nm, and ii) NIR spectral region covering 1600-2500 nm. Thereafter, both regions were amplified to 25 μJ of energy, in a single-stage optical parametric amplifier and compressed to 4.8 fs and 18 fs, respectively. The 18 fs, NIR pulses were guided through a 500 μm-thick mixture of acetic acid and water. Eventually, the transmitted light was detected by EOS, containing a 50 μm-thick BBO (Type II) crystal, where the 4.8 fs pulses were used as a probe. In the absence of any sample, the measured electric field of the excitation pulses goes to zero at temporal delays above 200 fs (Fig.1a)). By adding the sample, a background-free, molecular response is observed for temporal delays beyond 200 fs, as shown in Fig.1b). The NIR response of water molecules can be clearly detected in water concentrations as low as 3%. In summary, we presented the new concept of NIR molecular fieldoscopy covering the entire molecular finger-print region. Femtosecond molecular excitation allows for background-free detection of the molecular response and higher detection sensitivity, while the heterodyne detection in EOS enhances the detection dynamic range.
关键词： electro-optics sampling,water molecules,molecular fieldoscopy,near-infrared spectroscopy,vibrational mode
更新于2025-09-11 14:15:04
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Near infrared spectroscopic measurement of strain in rocks
摘要： The measurement of strain is a fundamental and widely studied parameter in engineering, rock mechanics, construction and materials testing. Contact sensors often used in these fields require contact with the target surface throughout the duration of a strain event. Non-contact methods typically require that that the measurement surface is prepared and often coated prior to testing. This paper considers the potential application of near infrared spectroscopy as a non-contact technique for the measurement of strain on natural surfaces. Excellent correlation was found between surface measurements of visible-NIR spectra and longitudinal strain taken during indirect Brazilian Disc Test for samples of sandstone, marble and basalt.
关键词： rock,indirect tensile strength,Strain measurement,near infrared spectroscopy
更新于2025-09-11 14:15:04