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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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Label-free Identification of Antibody-mediated Rejection in Cardiac Allograft Biopsies Using Infrared Spectroscopic Imaging
摘要： Background. Antibody-mediated rejection (AMR) in cardiac allograft recipients remains less well-understood than acute cellular rejection, is associated with worse outcomes, and portends a greater risk of developing chronic allograft vasculopathy. Diffuse immunohistochemical C4d staining of capillary endothelia in formalin-fixed, paraffin-embedded right ventricular endomyocardial biopsies is diagnostic of immunopathologic AMR but serves more as a late-stage marker. Infrared (IR) spectroscopy may be a useful tool in earlier detection of rejection. We performed mid-IR spectroscopy to identify a unique biochemical signature for AMR. Methods. A total of 30 posttransplant formalin-fixed paraffin-embedded right ventricular tissue biopsies (14 positive for C4d and 16 negative for C4d) and 14 native heart biopsies were sectioned for IR analysis. Infrared images of entire sections were acquired and regions of interest from cardiomyocytes were identified. Extracted spectra were averaged across many pixels within each region of interest. Principal component analysis coupled with linear discriminant analysis and predictive classifiers were applied to the data. Results. Comparison of averaged mid-IR spectra revealed unique features among C4d-positive, C4d-negative, and native heart biopsies. Principal component analysis coupled with linear discriminant analysis and classification models demonstrated that spectral features from the mid-IR fingerprint region of these 3 groups permitted accurate automated classification into each group. Conclusions. In cardiac allograft biopsies with immunopathologic AMR, IR spectroscopy reveals a biochemical signature unique to AMR compared with that of nonrejecting cardiac allografts and native hearts. Future study will focus on the predictive capabilities of this IR signature.
关键词： infrared spectroscopy,Antibody-mediated rejection,C4d,cardiac allograft,biochemical signature
更新于2025-09-12 10:27:22
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Coupling Waveguide-Based Micro-Sensors and Spectral Multivariate Analysis to Improve Spray Deposit Characterization in Agriculture
摘要： The leaf coverage surface is a key measurement of the spraying process to maximize spray efficiency. To determine leaf coverage surface, the development of optical micro-sensors that, coupled with a multivariate spectral analysis, will be able to measure the volume of the droplets deposited on their surface is proposed. Rib optical waveguides based on Ge-Se-Te chalcogenide films were manufactured and their light transmission was studied as a response to the deposition of demineralized water droplets on their surface. The measurements were performed using a dedicated spectrophotometric bench to record the transmission spectra at the output of the waveguides, before (reference) and after drop deposition, in the wavelength range between 1200 and 2000 nm. The presence of a hollow at 1450 nm in the relative transmission spectra has been recorded. This corresponds to the first overtone of the O–H stretching vibration in water. This result tends to show that the optical intensity decrease observed after droplet deposition is partly due to absorption by water of the light energy carried by the guided mode evanescent field. The probe based on Ge-Se-Te rib optical waveguides is thus sensitive throughout the whole range of volumes studied, i.e., from 0.1 to 2.5 μL. Principal Component Analysis and Partial Least Square as multivariate techniques then allowed the analysis of the statistics of the measurements and the predictive character of the transmission spectra. It confirmed the sensitivity of the measurement system to the water absorption, and the predictive model allowed the prediction of droplet volumes on an independent set of measurements, with a correlation of 66.5% and a precision of 0.39 μL.
关键词： principal component analysis (PCA),partial least squares (PLS),precision agriculture,droplet characterization,infrared spectroscopy,optical micro-sensors,crop protection
更新于2025-09-12 10:27:22
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EXPRESS: External Cavity Quantum Cascade Laser-Based Mid-Infrared Dispersion Spectroscopy for Qualitative and Quantitative Analysis of Liquid-Phase Samples
摘要： Acquisition of classical absorption spectra of liquids in the mid-IR range with quantum cascade lasers (QCLs) is often limited in sensitivity by noise from the laser source. Alternatively, measurement of molecular dispersion (i.e., refractive index) spectra poses an experimental approach that is immune to intensity fluctuations and further offers a direct relationship between the recorded signal and the sample concentration. In this work, we present an external cavity quantum cascade laser (EC-QCL) based Mach–Zehnder interferometer setup to determine dispersion spectra of liquid samples. We present two approaches for acquisition of refractive index spectra and compare the qualitative experimental results. Furthermore, the performance for quantitative analysis is evaluated. Finally, multivariate analysis of a spectrally complex mixture comprising three different sugars is performed. The obtained figures of merit by partial least squares (PLS) regression modelling compare well with standard absorption spectroscopy, demonstrating the potential of the introduced dispersion spectroscopic method for quantitative chemical analysis.
关键词： liquid phase,Mid-infrared spectroscopy,QCL,quantum cascade laser,dispersion spectroscopy,mid-IR spectroscopy
更新于2025-09-11 14:15:04
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Plasmonic Trimers for Dual-Frequency Surface-Enhanced Two-dimensional Infrared Spectroscopy
摘要： Extension of surface-enhanced two-dimensional infrared spectroscopy (SE-2DIR) to dual-frequency experiments allows to study dynamics and energy transport in thin molecular films by tagging and probing vibrational modes on different sites of the molecule. Measurements of cross-peaks involving transitions largely separated in frequency by SE-2DIR require plasmonic nanostructures with resonant excitations at the corresponding frequencies, where the associated enhanced near-fields spatially overlap and different molecular transitions are simultaneously enhanced in the same molecule. Gold trimer infrared antennas localize enhanced fields within the gap formed by their arms. We exploit the symmetry of trimer antennas to individually tune frequencies of the in-plane plasmonic excitations to match molecular transitions of interest. Dual-frequency SE-2DIR measurements are demonstrated on 4-azidobutyrate-N-hydroxysuccinimide ester with the cross-peaks between the carbonyl and azido stretching vibrational modes, separated by 370 cm-1, and the carbonyl and C-N-C stretching modes, separated by 550 cm-1. Excitation with cross-polarized laser pulses allows to selectively access appropriate plasmon excitations in resonance with the relevant molecular transitions. Our approach, based on the rational plasmon mode engineering, achieves significant enhancement of the cross-peak signals involving largely-separated transition frequencies, which is not possible with single broadband plasmon modes.
关键词： Surface-Enhanced Two-dimensional Infrared Spectroscopy,Dual-frequency,Molecular transitions,Cross-peaks,Gold trimer infrared antennas,Plasmonics,Hybrid Materials,Optical,Magnetic
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) - Field-Resolved Infrared Spectroscopy of Human Blood to Tackle Lung, Prostate and Breast Cancer Detection
摘要： Broadband mid-infrared spectroscopy of biofluids carries great potential for biological and biomedical applications, as it provides fast, reliable and label-free access to the molecular composition of the sample. When applied to human blood serum, a range of molecular contents can be quantified and specific changes in the absorption spectra, driven by diseases (e.g. cancer) can be identified and used for diagnostic purposes. One remaining challenge is the complexity of human serum: physiological phenotypes are driven by minor changes in concentration of thousands of different molecules. At the same time, although many low-abundance molecules are very informative for disease detection, these are often not detectable with conventional Fourier-Transform Infrared (FTIR) spectroscopy and quantum-cascade laser (QCL) based approaches due to a lack of sensitivity and specificity. Here we show how field-resolved spectroscopy (FRS) of few-cycle-excited molecular vibrations can be utilised to address these shortcomings and demonstrate its applicability for the measurement of human blood serum in a clinical setting. In a preparatory experiment, we quantitatively investigate the ability of FRS to detect small changes in the sample response by spiking blood serum with a defined concentration of dimethyl sulfone (DMSO2). We demonstrate that FRS is able to detect changes in molecular concentration down to the sub-μg/ml level in human blood serum, outperforming the sensitivity of FTIR- and QCL-based approaches. Hence, the smallest changes currently detectable by FRS are five orders of magnitude below the concentration of the most highly-abundant molecules in blood, implying a detectable concentration dynamic range of 105. Based on these results, we apply FRS for the first time in a real-world setting, a clinical study with a well-matched cohort of 195 control individuals and 58 lung, 41 prostate and 42 breast cancer patients and compare the obtained results to state-of-the-art FTIR measurements of the same samples. Corresponding infrared molecular fingerprints were recorded as time-domain sampled field oscillations emerging from the excited molecules in the serum samples (Fig. 1a). We find that investigation at different time windows (Fig. 1c-d) reveals a distinct temporal response of the samples originating from controls as compared to lung cancer patients. Preliminary analysis of the time-domain data with a random forest classifier reveals a high detection accuracy for cancer detection. Even though FRS, in this early stage of development, has considerably smaller spectral coverage as compared to FTIR, it reaches a similar rate of cancer detection efficiency. This suggests that the next generation FRS, with several octave spectral coverage, holds promise for outperforming FTIR fingerprinting substantially.
关键词： cancer detection,molecular vibrations,field-resolved spectroscopy,infrared spectroscopy,human blood
更新于2025-09-11 14:15:04
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Synthesis, chemical, theoretical studies, electrochemical, electrical and optical characterization of novel oligomer 2,2’-((1E,1’E)(2,5-bis(octyloxy)-1,4-phenylenevinylene)bis(6-(E)-2-(vinylquinolin))quinoline for OLED applications
摘要： A fluorescent pentamer 5QnQnPV with one phenyl central donor group surrounded by four quinoline acceptor groups set in a quadrupolar A-π-A-π-D-π-A-π-A electronic structure was synthesized. This compound is an organic semiconductor and shows a wide band fluorescence emission that spans from the blue to the red region with a maximum peak centered at 509 nm. In addition, its HOMO (? 5.4 eV)/LUMO (? 3.5 eV) energy values, determined by cyclic voltammetry, optical gap EgOpt of 2.18 and theoretical DT-DFT studies indicated a potential for OLED fabrication. When such device was made with a ITO/PEDOT:PSS/5QnQnPV/Al configuration it displayed a maximum electroluminescent response at 860 nm. The structural and physical characterization of this compound was performed using 1H and 13C Nuclear Magnetic Resonance, Fourier Transformed Infrared Spectroscopy, Mass Spectroscopy and Atomic Force Microscopy.
关键词： organic semiconductor,Atomic Force Microscopy,Fourier Transformed Infrared Spectroscopy,Mass Spectroscopy,electroluminescent response,fluorescent pentamer,Nuclear Magnetic Resonance,OLED
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) - Mid-Infrared Sensing by Induced Coherence in a Single Nonlinear Waveguide
摘要： Induced coherence (IC) between two spatially separated but indistinguishable spontaneous parametric down conversion (SPDC) processes underpins the recent revival of nonlinear interferometry and has led to new applications in quantum imaging and mid-infrared (MIR) spectroscopy [1,2]. These applications exploit induced coherence and the spectral or spatial correlations between signal and idler photons generated through SPDC. Here, we theoretically describe the phenomenon of IC in a general way by making use of a quantum-mechanical approach based on the classical Green’s function (GF) of the system [3,4]. Our formalism is well suited for treating generic linear optical properties of a system, including loss, and studying their influence on the IC phenomena. Moreover, our approach can account for arbitrary spatial profiles of the nonlinearity and hence can be used to describe generalized IC experiments with different number of photon-pair sources. Here we propose a sensing experiment using a single nonlinear waveguide [5] and investigate IC using our formalism. We find that in this case a substance under test inside or surrounding the waveguide can affect the IC during the generation stage along the nonlinear waveguide, making this a compact scheme for MIR spectroscopy without the need for MIR detectors.
关键词： spontaneous parametric down conversion,quantum imaging,nonlinear interferometry,mid-infrared spectroscopy,induced coherence
更新于2025-09-11 14:15:04