Search results for "near-infrared"
showing 10 items of 180 documents
Determination of fatty acids and lipid classes in salmon oil by near infrared spectroscopy
2017
International audience; Near-infrared (NIR) spectroscopy was evaluated as a rapid method for the determination of oleic, palmitic, linoleic and linolenic acids as well as omega-3, omega-6, and to predict polyunsaturated, monounsaturated and saturated fatty acids, together with triacylglycerides, diglycerides, free fatty acids and ergosterol in salmon oil. To do it, Partial Least Squares (PLS) regression models were applied to correlate NIR spectra with aforementioned fatty acids and lipid classes. Results obtained were validated in front of reference procedures based on high performance thin layer and gas chromatography. PLS-NIR has a good predictive capability with relative root mean squar…
Fiberless, Multi-Channel fNIRS-EEG System Based on Silicon Photomultipliers: Towards Sensitive and Ecological Mapping of Brain Activity and Neurovasc…
2020
Portable neuroimaging technologies can be employed for long-term monitoring of neurophysiological and neuropathological states. Functional Near-Infrared Spectroscopy (fNIRS) and Electroencephalography (EEG) are highly suited for such a purpose. Their multimodal integration allows the evaluation of hemodynamic and electrical brain activity together with neurovascular coupling. An innovative fNIRS-EEG system is here presented. The system integrated a novel continuous-wave fNIRS component and a modified commercial EEG device. fNIRS probing relied on fiberless technology based on light emitting diodes and silicon photomultipliers (SiPMs). SiPMs are sensitive semiconductor detectors, whose large…
Comparison of adsorption properties of commercial silica and rice husk ash (RHA) silica: A study by NIR spectroscopy
2021
Abstract Adsorption properties of Silica gel (commercial silica), rice husk ash (RHA) silica, and their hydrothermally treated products towards water molecules were studied in this work. RHA silica was prepared by heating rice husk to 650°C for 4 h after pretreatment with hydrochloric acid. Portions of the samples of silica were evacuated at 200℃ and then allowed to adsorb water molecules from the surrounding air at either 42 or 50% humidity. The near infrared spectra of these samples were measured at different time intervals during their adsorption of water molecules. The evolved near infrared spectra were analyzed using second derivative techniques. Adsorption properties of these samples …
A High-Efficiency Optical Energy Harvester based on a Low-Impedance Plasmonic Nanoantenna
2022
In this paper, for the first time, an investigation in terms of efficiency of an energy harvester based on a plasmonic nanorectenna array is proposed. The novel proposed mirrored-arrowhead nanoantenna presents a very low impedance value at the resonant frequency which reduces the mismatching between the antenna and rectifier circuit. Simulation results carried out by the CST 2020 Studio show a resistance value equal to 1.1 kohms at about 350 THz and a very wide bandwidth as the equivalent RF rhombic antenna. This study paves the way to nanoantennas for high-efficiency electromagnetic energy harvesting applications overcoming the photovoltaic technology.
En-Face differential absorption optical coherence tomography with gold nanorods as the contrast agent
2008
A new variety of nanoparticles showing unique and characteristic optical properties, appeals for its use as contrast agents in medical imaging. Gold nanospheres, nanorods and nanoshells with a silica core are new forms of promising contrast agents which can be tuned to specific absorption or scattering characteristics within the near-infrared (NIR) spectrum ranging from 650 - 1300 nm. They have the ability to be used for both image enhancement and as photosensitive markers due to their well designable scattering and absorption properties. Furthermore, their strong optical absorption permits treatment of malignant cells by photoablation processes, induced when heating them with a matched lig…
Comparison of a near-infrared reflectance spectroscopy system and skin conductance measurements for in vivo estimation of skin hydration: a clinical …
2017
Diffuse reflectance spectroscopy system was developed for estimation of skin hydration in the near-infrared spectral range of 900-1700 nm. Experimental setup consisted of a near-infrared spectrometer, Y-type fiber optics probe with 1 detection and 6 illumination fibers, halogen-tungsten light source and a PC. By analyzing diffuse reflectance spectrum, a parameter representing skin hydration by performing baseline correction and calculating the area under the 1450 nm water absorption maximum is proposed. A clinical study was performed acquiring data of skin hydration of 39 patients' forearm skin. Results of the developed system are compared to results obtained by a commercial device based on…
Motor Cortex Function in Fibromyalgia: A Study by Functional Near-Infrared Spectroscopy
2019
Previous studies indicated changes of motor cortex excitability in fibromyalgia (FM) patients and the positive results of transcranial stimulation techniques. The present study aimed to explore the metabolism of motor cortex in FM patients, in resting state and during slow and fast finger tapping, using functional Near-Infrared Spectroscopy (fNIRS), an optical method which detects in real time the metabolism changes in the cortical tissue. We studied 24 FM patients and 24 healthy subjects. We found a significant slowness of motor speed in FM patients compared to controls. During resting state and slow movement conditions, the metabolism of the motor areas was similar between groups. The oxy…
Challenges in the use of Near Infrared Spectroscopy for improving wood quality: A review
2018
Aims of study: Forestry-related companies require quality monitoring methods capable to pass a large number of samples. This review paper is dealing with the utilization of near infrared (NIR) technique for wood analysis.Area of study: We have a global point of view for NIR applications and characterization of different kind of wood species is considered.Material and methods: NIR spectroscopy is a fast, non-destructive technique, applicable to any biological material, demanding little or no sample preparation. NIR spectroscopy and multivariate analysis serve well in laboratories where the conditions are controlled. The main challenges to NIR spectroscopy technique in field conditions are mo…
Functional Near Infrared Spectroscopy System Validation for Simultaneous EEG-FNIRS Measurements
2019
Functional near-infrared spectroscopy (fNIRS) applied to brain monitoring has been gaining increasing relevance in the last years due to its not invasive nature and the capability to work in combination with other well–known techniques such as the EEG. The possible use cases span from neural-rehabilitation to early diagnosis of some neural diseases. In this work a wireline FPGA–based fNIRS system, that use SiPM sensors and dual-wavelength LED sources, has been designed and validated to work with a commercial EEG machine without reciprocal interference.
Standardized Hemorrhagic Shock Induction Guided by Cerebral Oximetry and Extended Hemodynamic Monitoring in Pigs.
2019
Hemorrhagic shock ranks among the main reasons for severe injury-related death. The loss of circulatory volume and oxygen carriers can lead to an insufficient oxygen supply and irreversible organ failure. The brain exerts only limited compensation capacities and is particularly at high risk of severe hypoxic damage.This article demonstrates the reproducible induction of life-threatening hemorrhagic shock in a porcine model by means of calculated blood withdrawal. We titrate shock induction guided by near-infrared spectroscopy and extended hemodynamic monitoring to display systemic circulatory failure, as well as cerebral microcirculatory oxygen depletion. In comparison to similar models tha…