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Near-infrared spectroscopy

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https://www.readbyqxmd.com/read/28547651/photoplethysmography-for-blood-volumes-and-oxygenation-changes-during-intermittent-vascular-occlusions
#1
T Y Abay, P A Kyriacou
Photoplethysmography (PPG) is an optical technique that measures blood volume variations. The main application of dual-wavelength PPG is pulse oximetry, in which the arterial oxygen saturation (SpO[Formula: see text]) is calculated noninvasively. However, the PPG waveform contains other significant physiological information that can be used in conjunction to SpO[Formula: see text] for the assessment of oxygenation and blood volumes changes. This paper investigates the use of near infrared spectroscopy (NIRS) processing techniques for extracting relative concentration changes of oxygenated ([Formula: see text]HbO[Formula: see text]), reduced ([Formula: see text]HHb) and total haemoglobin ([Formula: see text]tHb) from dual-wavelength PPG signals during intermittent pressure-increasing vascular occlusions...
May 25, 2017: Journal of Clinical Monitoring and Computing
https://www.readbyqxmd.com/read/28546809/comparison-of-brain-activation-during-motor-imagery-and-motor-movement-using-fnirs
#2
Alyssa M Batula, Jesse A Mark, Youngmoo E Kim, Hasan Ayaz
Motor-activity-related mental tasks are widely adopted for brain-computer interfaces (BCIs) as they are a natural extension of movement intention, requiring no training to evoke brain activity. The ideal BCI aims to eliminate neuromuscular movement, making motor imagery tasks, or imagined actions with no muscle movement, good candidates. This study explores cortical activation differences between motor imagery and motor execution for both upper and lower limbs using functional near-infrared spectroscopy (fNIRS)...
2017: Computational Intelligence and Neuroscience
https://www.readbyqxmd.com/read/28546376/noninvasive-monitoring-of-oxygen-and-ventilation
#3
Craig D Smallwood, Brian K Walsh
Noninvasive monitoring of oxygenation and ventilation is an essential part of pediatric respiratory care. Carbon dioxide, gas exchange monitoring, transcutaneous monitoring, near-infrared spectroscopy, pulse oximetry, and electrical impedance tomography are examined. Although some of these technologies have been utilized for decades, incorporation into mechanical ventilators and recently developed methods may provide important clinical insights in a broader patient range. Less mature technologies (electrical impedance tomography and near-infrared spectroscopy) have been of particular interest, since they offer easy bedside application and potential for improved care of children with respiratory failure and other disorders...
June 2017: Respiratory Care
https://www.readbyqxmd.com/read/28544947/measuring-cortical-motor-hemodynamics-during-assisted-stepping-an-fnirs-feasibility-study-of-using-a-walker
#4
Andrea Cristina de Lima-Pardini, Guilherme A Zimeo Morais, Joana Bisol Balardin, Daniel Boari Coelho, Nametala Maia Azzi, Luis Augusto Teixeira, João Ricardo Sato
Walkers are commonly prescribed worldwide to individuals unable to walk independently. Walker usage leads to improved postural control and voluntary movement during step. In the present study, we aimed to provide a concept-proof on the feasibility of an event-related protocol integrating the analyses of biomechanical variables of step initiation and functional near-infrared spectroscopy (fNIRS) to measure activation of the supplementary motor area (SMA) while using a walker. Healthy young participants were tested while stepping with versus without the use of the walker...
May 17, 2017: Gait & Posture
https://www.readbyqxmd.com/read/28543094/mechanism-of-graphene-induced-cytotoxicity-role-of-endonucleases
#5
Tariq Fahmi, La Donna Branch, Zeid A Nima, Dae Song Jang, Alena V Savenka, Alexandru S Biris, Alexei G Basnakian
Graphene, a crystalline allotrope or carbon, presents numerous useful properties; however, its toxicity is yet to be determined. One of the most dramatic and irreversible toxic abilities of carbon nanomaterials is the induction of DNA fragmentation produced by endogenous cellular endonucleases. This study demonstrated that pristine graphene exposed to cultured kidney tubular epithelial cells is capable of inducing DNA fragmentation measured by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, which is usually associated with cell death...
May 24, 2017: Journal of Applied Toxicology: JAT
https://www.readbyqxmd.com/read/28539730/near-infrared-spectroscopy-as-a-process-analytical-technology-tool-for-monitoring-the-parching-process-of-traditional-chinese-medicine-based-on-two-kinds-of-chemical-indicators
#6
Kaiyue Li, Weiying Wang, Yanping Liu, Su Jiang, Guo Huang, Liming Ye
BACKGROUND: The active ingredients and thus pharmacological efficacy of traditional Chinese medicine (TCM) at different degrees of parching process vary greatly. OBJECTIVE: Near-infrared spectroscopy (NIR) was used to develop a new method for rapid online analysis of TCM parching process, using two kinds of chemical indicators (5-(hydroxymethyl) furfural [5-HMF] content and 420 nm absorbance) as reference values which were obviously observed and changed in most TCM parching process...
April 2017: Pharmacognosy Magazine
https://www.readbyqxmd.com/read/28539354/cerebral-oxygenation-and-regional-cerebral-perfusion-responses-with-resistance-breathing-during-central-hypovolemia
#7
Victoria L Kay, Justin Daniel Sprick, Caroline A Rickards
Resistance breathing improves tolerance to central hypovolemia induced by lower body negative pressure (LBNP), but this is not related to protection of anterior cerebral blood flow (indexed by mean middle cerebral artery velocity, MCAv). We hypothesized that inspiratory resistance breathing improves tolerance to central hypovolemia by maintaining cerebral oxygenation (ScO2), and protecting cerebral blood flow in the posterior cerebral circulation (indexed by posterior cerebral artery velocity, PCAv). Eight subjects (4M/4F) completed two experimental sessions of a presyncopal-limited LBNP protocol (3 mmHg/min onset rate) with and without (Control) resistance breathing via an impedance threshold device (ITD)...
May 24, 2017: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology
https://www.readbyqxmd.com/read/28538235/what-should-we-do-about-low-blood-pressure-in-preterm-infants
#8
Eugene M Dempsey
The management of preterm infants with low blood pressure soon after birth remains unresolved. The definition of what constitutes low blood pressure is uncertain. At birth, mean blood pressure appears to be gestation specific and increases in the first few days of life. Antenatal steroids, delayed cord clamping, and the avoidance of mechanical ventilation are all associated with higher mean blood pressure and less hypotension after birth. Rates of hypotension of 15-50% have been reported in various studies of extremely preterm infants...
2017: Neonatology
https://www.readbyqxmd.com/read/28538108/moderate-to-vigorous-physical-activity-executive-functions-and-prefrontal-brain-oxygenation-in-children-a-functional-near-infrared-spectroscopy-study
#9
Manuel Mücke, Christian Andrä, Markus Gerber, Uwe Pühse, Sebastian Ludyga
Despite accumulating evidence that regular exercise improves executive functioning, the underlying neurophysiological mechanisms have rarely been investigated. The present study aimed to compare cognitive performance as well as task-specific concentration changes in oxygenated haemoglobin in the prefrontal cortex between children with higher and lower moderate-to-vigorous physical activity (MVPA). Physical activity was measured over 7 consecutive days using actigraphy. Afterwards, participants (N = 50) completed verbal fluency tests (VFTs) and mental arithmetic (MA) for the assessment of cognitive flexibility and working memory capacity...
May 24, 2017: Journal of Sports Sciences
https://www.readbyqxmd.com/read/28538102/effects-of-wet-blending-on-detection-of-melamine-in-spray-dried-lactose
#10
Betsy Jean Yakes, Marti M Bergana, Peter F Scholl, Magdi M Mossoba, Sanjeewa R Karunathilaka, Luke K Ackerman, Jason D Holton, Boyan Gao, Jeffrey C Moore
During the development of rapid screening methods to detect economic adulteration, spray-dried milk powders prepared by dissolving melamine in liquid milk exhibited an unexpected loss of characteristic melamine features in the NIR and Raman spectra. To further characterize this "wet-blending" phenomenon, spray-dried melamine and lactose samples were produced as a simplified model and investigated by near-infrared spectroscopy, Raman spectroscopy, 1H NMR, and DART-FTMS. In contrast to dry-blended samples, characteristic melamine bands in NIR and Raman spectra disappeared or shifted in wet-blended lactose-melamine samples...
May 24, 2017: Journal of Agricultural and Food Chemistry
https://www.readbyqxmd.com/read/28537504/express-fecal-near-infrared-reflectance-spectroscopy-prediction-of-the-feed-value-of-temperate-forages-for-ruminants-and-some-parameters-of-the-chemical-composition-of-feces-efficiency-of-four-calibration-strategies
#11
Donato Andueza, Fabienne Picard, Dominique Dozias, Jocelyne Aufrère
No abstract text is available yet for this article.
January 1, 2017: Applied Spectroscopy
https://www.readbyqxmd.com/read/28537417/express-fiber-content-measurement-of-wool-cashmere-blends-using-near-infrared-spectroscopy
#12
Jinfeng Zhou, Rongwu Wang, Xiongying Wu, Bugao Xu
No abstract text is available yet for this article.
January 1, 2017: Applied Spectroscopy
https://www.readbyqxmd.com/read/28536713/calibration-transfer-of-near-infrared-spectroscopy-by-canonical-correlation-analysis-coupled-with-wavelet-transform
#13
Jun Bin, Xin Li, Wei Fan, Ji-Heng Zhou, Cheng-Wei Wang
Calibration model transfer has played a prominent role in the practical application of NIR spectral analysis. The change of instruments and sample physical states may lead to variation of the NIR spectrum, which results in the applicability of the model in judicatory practice being unsatisfactory. Therefore, a transfer for the calibration model considering both the variation of instruments and sample states is a necessity to ensure its availability. In this paper, a novel approach, namely canonical correlation analysis coupled with wavelet transform (WTCCA), was proposed for calibration transfer between two near infrared spectrometers (a portable and a laboratory instrument), and simultaneously, among three physical states (tobacco powder, tobacco filament and intact leaf) to determine the content of total sugars, reducing sugars, and nicotine in tobacco leaf samples, respectively...
May 24, 2017: Analyst
https://www.readbyqxmd.com/read/28536508/when-cooperation-was-efficient-or-inefficient-functional-near-infrared-spectroscopy-evidence
#14
Michela Balconi, Maria E Vanutelli
Cooperation is a construct within social cognition that requires both self-perception and the comprehension of others' actions. In the case of synchronized activities the adoption of common strategies is crucial, but this process can be strongly influenced by those variables. In fact, self-perceived efficacy within the social exchange can affect the motivational components toward the creation of synergic actions. Thus, what happens when our performance is efficient or inefficient during cooperation? This question was answered in the present study where we compared behavioral performance and neural activation across different conditions where subjects received an external feedback assessing a good or a poor outcome during a cooperative game...
2017: Frontiers in Systems Neuroscience
https://www.readbyqxmd.com/read/28536052/real-time-measurement-of-cerebral-blood-flow-during-and-after-repetitive-transcranial-magnetic-stimulation-a-near-infrared-spectroscopy-study
#15
Eunhee Park, Min Jae Kang, Ahee Lee, Won Hyuk Chang, Yong-Il Shin, Yun-Hee Kim
OBJECTIVES: To confirm the interhemispheric modulation induced by low-frequency repetitive transcranial magnetic stimulation (rTMS) over the primary motor cortex, real-time regional cerebral blood flow (rCBF) was assessed using functional near-infrared spectroscopy (fNIRS) in the contralateral primary motor cortex (M1) and premotor cortex (PM). METHODS: Ten right-handed healthy subjects completed two experimental sessions that were randomly arranged for real or sham rTMS session...
May 20, 2017: Neuroscience Letters
https://www.readbyqxmd.com/read/28535670/ultrafast-spectroscopy-reveals-electron-transfer-cascade-that-improves-hydrogen-evolution-with-carbon-nitride-photocatalysts
#16
Kathryn L Corp, Cody W Schlenker
Solar hydrogen generation from water represents a compelling component of a future sustainable energy portfolio. Recently, chemically-robust heptazine-based polymers known as graphitic carbon nitrides (g-C3N4) have emerged as promising photocatalysts for hydrogen evolution using visible light while withstanding harsh chemical environments. However, since g-C3N4 electron transfer dynamics are poorly understood, rational design rules for improving activity remain unclear. Here, we use visible and near-infrared femtosecond transient absorption (TA) spectroscopy to reveal an electron transfer cascade that correlates with a near-doubling in photocatalytic activity from 2050 µmol h(-1)g(-1) to 3810 µmol h(-1)g(-1) when we infuse a suspension of bulk g-C3N4 with 10% mass loading of chemically exfoliated carbon nitride...
May 23, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28535459/spectra-structure-correlations-of-saturated-and-unsaturated-medium-chain-fatty-acids-near-infrared-and-anharmonic-dft-study-of-hexanoic-acid-and-sorbic-acid
#17
Justyna Grabska, Krzysztof B Beć, Mika Ishigaki, Marek J Wójcik, Yukihiro Ozaki
Quantum chemical reproduction of entire NIR spectra is a new trend, enabled by contemporary advances in the anharmonic approaches. At the same time, recent increase of the importance of NIR spectroscopy of biological samples raises high demand for gaining deeper understanding of NIR spectra of biomolecules, i.e. fatty acids. In this work we investigate saturated and unsaturated medium-chain fatty acids, hexanoic acid and sorbic acid, in the near-infrared region. By employing fully anharmonic density functional theory (DFT) calculations we reproduce the experimental NIR spectra of these systems, including the highly specific spectral features corresponding to the dimerization of fatty acids...
May 13, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28534917/charge-stabilizing-tris-triphenylamine-zinc-porphyrin-carbon-nanotube-hybrids-synthesis-characterization-and-excited-state-charge-transfer-studies
#18
Luis M Arellano, Myriam Barrejón, Habtom B Gobeze, María J Gómez-Escalonilla, José Luis G Fierro, Francis D'Souza, Fernando Langa
Functionalization of single-walled (SWCNTs) and double-walled carbon nanotubes (DWCNTs) with a charge stabilizing zinc porphyrin functionalized with triphenylamine entities has been accomplished. The synthetic approach involved the reaction of tris-(triphenylamine)porphyrinato zinc(ii) with iodobenzene functionalized nanotubes through a Sonogashira C-C cross coupling reaction under microwave irradiation conditions. Evidence of covalent functionalization and the extent of functionalization was obtained from systematic studies carried out by AFM, TGA, XPS and Raman spectroscopy techniques...
May 23, 2017: Nanoscale
https://www.readbyqxmd.com/read/28534842/rapid-prediction-of-moisture-content-in-intact-green-coffee-beans-using-near-infrared-spectroscopy
#19
Adnan Adnan, Dieter von Hörsten, Elke Pawelzik, And Daniel Mörlein
Moisture content (MC) is one of the most important quality parameters of green coffee beans. Therefore, its fast and reliable measurement is necessary. This study evaluated the feasibility of near infrared (NIR) spectroscopy and chemometrics for rapid and non-destructive prediction of MC in intact green coffee beans of both Coffeaarabica (Arabica) and Coffeacanephora (Robusta) species. Diffuse reflectance (log 1/R) spectra of intact beans were acquired using a bench top Fourier transform NIR instrument. MC was determined gravimetrically according to The International Organization for Standardization (ISO) 6673...
May 19, 2017: Foods (Basel, Switzerland)
https://www.readbyqxmd.com/read/28534831/rapidly-simultaneous-determination-of-six-effective-components-in-cistanche-tubulosa-by-near-infrared-spectroscopy
#20
Xinhong Wang, Xiaoguang Wang, Yuhai Guo
Quantitative determination of multiple effective components in a given plant usually requires a very large amount of authentic natural products. In this study, we proposed a rapid and non-destructive method for the simultaneous determination of echinacoside, verbascoside, mannitol, sucrose, glucose and fructose in Cistanche tubulosa by near infrared spectroscopy (NIRS). Near infrared diffuse reflectance spectroscopy (DRS) and high performance liquid chromatography (HPLC) were conducted on 116 batches of C. tubulosa samples...
May 19, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
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