217,451 research outputs found

    Near-infrared spectroscopy after high-risk congenital heart surgery in the paediatric intensive care unit

    Get PDF
    Objective: To establish whether the use of near-infrared spectroscopy is potentially beneficial in high-risk cardiac infants in United Kingdom paediatric intensive care units. Design: A prospective observational pilot study. Setting: An intensive care unit in North West England. Patients: A total of 10 infants after congenital heart surgery, five with biventricular repairs and five with single-ventricle physiology undergoing palliation. Interventions: Cerebral and somatic near-infrared spectroscopy monitoring for 24 hours post-operatively in the intensive care unit. Measurement and main results: Overall, there was no strong correlation between cerebral near-infrared spectroscopy and mixed venous oxygen saturation (r=0.48). At individual time points, the correlation was only strong (r=0.74) 1 hour after admission. The correlation was stronger for the biventricular patients (r=0.68) than single-ventricle infants (r=0.31). A strong inverse correlation was demonstrated between cerebral near-infrared spectroscopy and serum lactate at 3 of the 5 post-operative time points (1, 4, and 12 hours: r=-0.76, -0.72, and -0.69). The correlation was stronger when the cerebral near-infrared spectroscopy was 60%, which was r=-0.50. No correlations could be demonstrated between (average) somatic near-infrared spectroscopy and serum lactate (r=-0.13, n=110) or mixed venous oxygen saturation and serum lactate. There was one infant who suffered a cardiopulmonary arrest, and the cerebral near-infrared spectroscopy showed a consistent 43 minute decline before the event. Conclusions: We found that cerebral near-infrared spectroscopy is potentially beneficial as a non-invasive, continuously displayed value and is feasible to use on cost-constrained (National Health Service) cardiac intensive care units in children following heart surgery

    Study on single calibration of near infrared reflectance spectroscopy for lignin

    Get PDF
    The study of single calibration of near infrared reflectance srectroscory for lignin was done using 50 feed samples and its paired 50 fecal samrles from dairy cows. These samrles were collected from digestion trials. in which the in vivo digestibility values were deternlined, The dlgC-ostibillty of these feed samples were separated into two grours, namely Italian ryegruss only (n= 19) and combinution of Italian ryegrass and concentmte (n=31), The NIRS srectm or these samrles were recorded using I'aciflc Scientific (Neotec) model 6500 (Perstorp Analytical, Silver Srring, MD) instrument equirrl'Cl with lSI software (InfraSoft International, Port Matilda, PAl for analysIs, Three arproach methods for devcloring the single calibmtion were, (I) Lignin in feed and feces was detcn;1ined usmg lignin calibratIOn developed from Italian ryegrass (L1RG): (2) Lignin of ft.'Cd and feces was detennined lIsing lignin calibmtion developed ITom feces (LFEC): and (3) Lignin oC feed and feces were detemlined using the caiibmtion equation for lignin develorcd from Si.U11rles of fecdstufl's wld feces (LMIX). The resulb showed that lignin of feed and feces in il~ function for digestibility marker could be detennincd by single calibration developed from samrles consisting of Italian ryegm~s, concentrates and feces

    Comparison of visible-near infrared and mid-infrared spectroscopy for classification of Huanglongbing and citrus canker infected leaves

    Get PDF
    In this study, visible-near infrared spectroscopy and mid-infrared spectroscopy were compared to evaluate their applicability in classifying citrus leaves infected with canker and HLB from healthy citrus leaves. ¬†The visible-near infrared spectra in the range 350-2,500 nm and mid-infrared spectra in the range of 5.15-10.72 ¬Ķm were collected from healthy and diseased (canker, HLB) leaves. ¬†Following the spectral data collection, the data were preprocessed and classification was performed using two classifiers, quadratic discriminant analysis (QDA) and k-nearest neighbor (kNN). ¬†The classifiers (QDA, kNN) resulted in an average overall and individual class classification accuracy of about 90% or more. ¬†Mid-infrared spectroscopy provided high classification accuracy especially in identifying HLB-infected leaves; while, visible-near infrared spectroscopy was better suited for canker detection. ¬†Both methods have their own merits such as visible-near infrared spectroscopy offers non-invasive disease detection; while mid-infrared spectroscopy represents the chemical profile of the leaf structure, which may allow potential detection in asymptomatic stages. ¬† Keywords: disease detection, classification, quadratic discriminant analysis, k-nearest neighbo

    Spectroscopic Analysis and Xray Diffraction of Zinnwaldite

    Get PDF
    This paper describes an X-ray diffraction and spectroscopic study, including infrared, near-infrared and Raman spectroscopy of some selected zinnwaldites. In general, zinnwaldite forms a member of the trioctahedral true micas with characteristically Li in the octahedral positions and low iron contents. Although the infrared spectrum of zinnwaldite has been described before, near infrared and Raman spectroscopy have not been used so far to study this mineral. X-ray diffraction showed that all the samples reported in this study have the 1M structure. The Raman spectra are characterised by a strong band at 700-705 cm-1 plus a broad band associated with the SiO modes around 1100 cm-1. Less intense bands are observed around 560, 475, 403 and 305 cm-1. The corresponding IR spectra show strong overlapping SiO modes around 1020 cm-1 plus less intense bands around 790, 745, 530, 470-475 and 440 cm-1. Two overlapping OH-stretching modes can be observed around 3550-3650 cm-1, in agreement with a broad band in the IR around 3450 cm-1 and a complex band around 3630 cm-1. The near-IR spectra basically reflect combination and overtone bands associated with protons in the zinnwaldite structure. A very broad band observed around 5230 cm-1 is characteristic for adsorbed water while bands around 4530, 4435 and 4260 cm-1 can be ascribed to metal-hydroxyl groups

    Using Functional Near Infrared Spectroscopy (fNIRS) to study dynamic stereoscopic depth perception

    Get PDF
    The parietal cortex has been widely implicated in the processing of depth perception by many neuroimaging studies, yet functional near infrared spectroscopy (fNIRS) has been an under-utilised tool to examine the relationship of oxy- ([HbO]) and de-oxyhaemoglobin ([HbR]) in perception. Here we examine the haemodynamic response (HDR) to the processing of induced depth stimulation using dynamic random-dot-stereograms (RDS). We used fNIRS to measure the HDR associated with depth perception in healthy young adults (n¬†=¬†13, mean age 24). Using a blocked design, absolute values of [HbO] and [HbR] were recorded across parieto-occipital and occipital cortices, in response to dynamic RDS. Control and test images were identical except for the horizontal shift in pixels in the RDS that resulted in binocular disparity and induced the percept of a 3D sine wave that 'popped out' of the test stimulus. The control stimulus had zero disparity and induced a 'flat' percept. All participants had stereoacuity within normal clinical limits and successfully perceived the depth in the dynamic RDS. Results showed a significant effect of this complex visual stimulation in the right parieto-occipital cortex (p¬†<¬†0.01, ő∑(2)¬†=¬†0.54). The test stimulus elicited a significant increase in [HbO] during depth perception compared to the control image (p¬†<¬†0.001, 99.99¬†% CI [0.008-0.294]). The similarity between the two stimuli may have resulted in the HDR of the occipital cortex showing no significant increase or decrease of cerebral oxygenation levels during depth stimulation. Cerebral oxygenation measures of [HbO] confirmed the strong association of the right parieto-occipital cortex with processing depth perception. Our study demonstrates the validity of fNIRS to investigate [HbO] and [HbR] during high-level visual processing of complex stimuli

    Effect of agro-climatic conditions on near infrared spectra of extra virgin olive oils

    Get PDF
    Authentication of extra virgin olive oil requires fast and cost-effective analytical procedures, such as near infrared spectroscopy. Multivariate analysis and chemometrics have been successfully applied in several papers to gather qualitative and quantitative information of extra virgin olive oils from near infrared spectra. Moreover, there are many examples in the literature analysing the effect of agro-climatic conditions on food content, in general, and in olive oil components, in particular. But the majority of these studies considered a factor, a non-numerical variable, containing this meteorological information. The present work uses all the agro-climatic data with the aim of highlighting the linear relationships between them and the near infrared spectra. The study begins with a graphical motivation, continues with a bivariate analysis and, finally, applies redundancy analysis to extend and confirm the previous conclusions.Peer Reviewe

    Carbohydrate Analysis by NIRS-Chemometrics

    Get PDF
    Near-infrared spectroscopy (NIRS) is a high-throughput, low-cost, solvent-free, and nondestructive analytical tool. Chemometrics is the science that employs statistical and mathematical methods to explain near-infrared spectra; it has been proven that when they are coupled, their effectiveness highly improved in-depth carbohydrate characterization. This chapter focuses on the fundamentals of near-infrared spectroscopy in the study of carbohydrates, as well as the application of partial least squares regression (PLSR) and principal component analysis (PCA), as the most useful chemometric techniques involved in carbohydrate analysis. The theoretical aspects and practical applications starting from simple to complex carbohydrates mixtures are covered. Indeed, the contributions from different fields extend the implementation of near-infrared spectroscopy from industrial quality control to scientific research

    A new survey of cool supergiants in the Magellanic Clouds

    Get PDF
    In this study, we conduct a pilot program aimed at the red supergiant population of the Magellanic Clouds. We intend to extend the current known sample to the unexplored low end of the brightness distribution of these stars, building a more representative dataset with which to extrapolate their behaviour to other Galactic and extra-galactic environments. We select candidates using only near infrared photometry, and with medium resolution multi-object spectroscopy, we perform spectral classification and derive their line-of-sight velocities, confirming the nature of the candidates and their membership to the clouds. Around two hundred new RSGs have been detected, hinting at a yet to be observed large population. Using near and mid infrared photometry we study the brightness distribution of these stars, the onset of mass-loss and the effect of dust in their atmospheres. Based on this sample, new a priori classification criteria are investigated, combining mid and near infrared photometry to improve the observational efficiency of similar programs as this.Comment: 39 pages, 10 figures. Accepted for publication in A&

    Mid-Infrared Spectroscopy and Challenges in Industrial Environment

    Get PDF
    In recent years, Mid-Infrared spectroscopy has garnered lot of attention from researchers and industries due to the availability of industrial grade room temperature Intra-band and Quantum Cascade Lasers. These lasers are repeatable in their performance and along with Near-Infrared Lasers, it has opened the entire Infra-red spectral band for industrial applications. This enabled widespread applications of tunable laser absorption spectroscopy for real-time, in-situ and non-invasive gas sensing. Though several spectroscopy techniques are currently available, Mid-Infrared Absorption Spectroscopy offers us a unique advantage of measurement of trace gas concentrations of few gases which has very weak transitions in Near-Infrared region. The objectives of this chapter are to discuss about the spectroscopy technique commonly used for Mid-Infrared Lasers, a comparative study with other techniques, noise and some challenges remaining for industrial applications

    Near infrared spectroscopy of benzoic acid adsorbed on montmorillonite

    Get PDF
    The adsorption of benzoic acid on both sodium and calcium montmorillonites has been studied by near infrared spectroscopy complimented with infrared spectroscopy. Upon adsorption of benzoic acid additional near infrared bands are observed at 8665 cm-1 and assigned to an interaction of benzoic acid with the water of hydration. Upon adsorption of the benzoic acid on Na-Mt, the NIR bands are now observed at 5877, 5951, 6028 and 6128 cm-1 and are assigned to the overtone and combination bands of the CH fundamentals. Additional bands at 4074, 4205, 4654 and 4678 cm-1 are attributed to CH combination bands resulting from the adsorption of the benzoic acid. Benzoic acid is used as a model molecule for adsorption studies. The application of near infrared spectroscopy to the study of adsorption has the potential for the removal of acids from polluted aqueous systems
    • ‚Ķ
    corecore