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1.
Adv Exp Med Biol ; 1232: 323-329, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31893427

RESUMO

Recent guidelines on cardiopulmonary resuscitation (CPR) have stressed the necessity to improve the quality of CPR. Our previous studies demonstrated the usefulness of monitoring cerebral blood oxygenation (CBO) during CPR by near-infrared spectroscopy (NIRS). The present study evaluates whether the NIRO-CCR1, a new NIRS device, is as useful in the clinical setting as the NIRO-200NX. We monitored CBO in 20 patients with cardiac arrest by NIRS. On the arrival of patients at the emergency department, the attending physician immediately assessed whether the patient was eligible for this study after conventional advanced life support and, if eligible, measured CBO in the frontal lobe by NIRS. We found that in all patients, the cerebral blood flow waveform was in synchrony with the chest compressions. Moreover, the tissue oxygenation index increased following cardiopulmonary bypass (CPB) in patients undergoing CPB, including one patient in whom CBO was monitored using the NIRO-CCR1. In addition, although the NIRO-CCR1 could display the pulse rate (Tempo) in real time, Tempo was not always detected, despite detection of the cerebral blood flow waveform. This suggested that chest compressions may not have been effective, indicating that the NIRO-CCR1 also seems useful to assess the quality of CPR. This study suggests that the NIRO-CCR1 can measure CBO during CPR in patients with cardiac arrest as effectively as the NIRO-200NX; in addition, the new NIRO-CCR1 may be even more useful, especially in prehospital fields (e.g. in an ambulance), since it is easy to carry.


Assuntos
Reanimação Cardiopulmonar , Circulação Cerebrovascular , Parada Cardíaca , Monitorização Fisiológica , Oximetria , Espectroscopia de Luz Próxima ao Infravermelho , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Monitorização Fisiológica/instrumentação , Monitorização Fisiológica/normas , Oximetria/instrumentação , Oximetria/normas , Projetos Piloto , Espectroscopia de Luz Próxima ao Infravermelho/instrumentação , Espectroscopia de Luz Próxima ao Infravermelho/normas
2.
Adv Exp Med Biol ; 1232: 331-337, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31893428

RESUMO

Obesity, a risk factor of coronary artery disease, is known to cause peripheral microcirculatory disturbances. This study evaluated the relationship between the degree of obesity and peripheral microcirculatory disturbances, using peripheral near infrared spectroscopy (NIRS) with a vascular occlusion test (VOT). We compared correlations between the NIRS parameter changes induced by VOT and body mass index (BMI) in patients with and without statin therapy. A NIRS probe was set on the right thenar eminence, brachial artery blood flow was blocked for 3 min, and then released. Although total hemoglobin (ΔcHb), deoxyhemoglobin (ΔHHb) and tissue oxygenation index (ΔTOI) were not correlated with BMI, a significant negative correlation was found between oxyhemoglobin (ΔO2Hb) and BMI in the overall study population (r = -0.255, p-value 0.02). In addition, a significant negative correlation was found between ΔO2Hb and BMI in patients without statin therapy (r = -0.353, p-value 0.02) but not in patients with statin therapy (r = -0.181, p-value 0.27). These findings suggest that ΔO2Hb may be a useful indicator to assess peripheral microcirculation.


Assuntos
Índice de Massa Corporal , Doença da Artéria Coronariana , Espectroscopia de Luz Próxima ao Infravermelho , Idoso , Feminino , Humanos , Inibidores de Hidroximetilglutaril-CoA Redutases/uso terapêutico , Masculino , Microcirculação/fisiologia , Oxigênio , Consumo de Oxigênio , Oxiemoglobinas/metabolismo , Fatores de Risco , Espectroscopia de Luz Próxima ao Infravermelho/normas
3.
Eur J Appl Physiol ; 119(8): 1799-1808, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31177324

RESUMO

PURPOSE: The recovery of muscle oxygen consumption (m[Formula: see text]O2) after exercise provides a measure of skeletal muscle mitochondrial capacity, as more and better-functioning mitochondria will be able to restore m[Formula: see text]O2 faster to the pre-exercise state. The aim was to measure muscle mitochondrial capacity using near-infrared spectroscopy (NIRS) within a healthy, normally active population and relate this to parameters of aerobic fitness, investigating the applicability and relevance of using NIRS to assess muscle mitochondrial capacity non-invasively. METHODS: Mitochondrial capacity was analysed in the gastrocnemius and flexor digitorum superficialis (FDS) muscles of eight relatively high-aerobic fitness ([Formula: see text]O2peak ≥ 57 mL/kg/min) and eight relatively low-aerobic fitness male subjects ([Formula: see text]O2peak ≤ 47 mL/kg/min). Recovery of whole body [Formula: see text]O2, i.e. excess post-exercise oxygen consumption (EPOC) was analysed after a cycling protocol. RESULTS: Mitochondrial capacity, as analysed using NIRS, was significantly higher in high-fitness individuals compared to low-fitness individuals in the gastrocnemius, but not in the FDS (p = 0.0036 and p = 0.20, respectively). Mitochondrial capacity in the gastrocnemius was significantly correlated with [Formula: see text]O2peak (R2 = 0.57, p = 0.0019). Whole body [Formula: see text]O2 recovery was significantly faster in the high-fitness individuals (p = 0.0048), and correlated significantly with mitochondrial capacity in the gastrocnemius (R2 = 0.34, p = 0.028). CONCLUSION: NIRS measurements can be used to assess differences in mitochondrial muscle oxygen consumption within a relatively normal, healthy population. Furthermore, mitochondrial capacity correlated with parameters of aerobic fitness ([Formula: see text]O2peak and EPOC), emphasising the physiological relevance of the NIRS measurements.


Assuntos
Exercício , Mitocôndrias Musculares/metabolismo , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Adolescente , Adulto , Humanos , Masculino , Consumo de Oxigênio , Aptidão Física , Espectroscopia de Luz Próxima ao Infravermelho/normas
4.
Spectrochim Acta A Mol Biomol Spectrosc ; 220: 117098, 2019 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-31129498

RESUMO

Single kernel near-infrared spectroscopy (SKNIRS) could aid in the quality screening of early-generation seeds, to improve the efficiency of seed breeding. However, the application of SKNIRS is limited due to the irregular physical characteristics, the heterogeneous constituent distributions of individual seeds, and the insufficient detection accuracy of the reference method. The reported near-infrared detection results of single seeds are often less accurate than those of dehusked seeds and seed flour. In this paper, a calibration transfer-optimized single kernel near-infrared spectroscopic method is proposed. This method aims to accurately detect the chemical composition of single seeds by using the calibration model of the corresponding dehusked seeds or seed flour. The proposed method was applied to the analysis of the protein content of a single rice kernel. The near-infrared transmission spectra of three forms of rice (single rice kernel (SRK), single brown rice kernel (SBK) and rice flour (RF)) of 201 individual rice seeds and the corresponding protein content values were obtained. By comparing different pretreatment methods and spectral ranges, the spectral range 950-1250 nm, the standard normal variate transformation (SNV) pretreatment, and 9 PLS factors were selected to construct the optimal partial least squares (PLS) regression models. Then, the protein content of single rice kernels were determined through two different methods: (i) the direct method, in which single rice kernels were analyzed using the single rice kernel model directly; and (ii) the proposed method, in which the spectra of single rice kernels were transferred into the spectra of single brown rice kernels and rice flours with a calibration transfer algorithm, spectral space transformation (SST), and were analyzed by the respective calibration models. The external validation coefficient correlation (R) value of the direct method was 0.971, and the R values of the proposed method were 0.962 (SBK) and 0.975 (RF). The root mean square error of prediction (RMSEP) value of the direct method was 0.423, and the RMSEP of the proposed method were 0.480 (SBK) and 0.401 (RF). In addition, the transfer results among the spectra of three forms of rice were compared. By comparison, the results of the proposed method are fairly close to the results of the direct method. The results indicate that the spectra generated from one individual rice seed can be transferred freely among the three forms by means of calibration transfer. The proposed method is a promising way to overcome the challenges associated with analyzing individual seeds and to improve SKNIRS.


Assuntos
Oryza/química , Proteínas de Plantas/análise , Sementes/química , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Algoritmos , Calibragem , Farinha/análise , Análise Multivariada , Proteínas de Plantas/química , Reprodutibilidade dos Testes , Espectroscopia de Luz Próxima ao Infravermelho/normas
5.
Sensors (Basel) ; 19(9)2019 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-31035325

RESUMO

The feasibility of near-infrared spectroscopy (NIR) to detect chlorogenic acid, luteoloside and 3,5-O-dicaffeoylquinic acid in Chrysanthemum was investigated. An NIR spectroradiometer was applied for data acquisition. The reference values of chlorogenic acid, luteoloside, and 3,5-O-dicaffeoylquinic acid of the samples were determined by high-performance liquid chromatography (HPLC) and were used for model calibration. The results of six preprocessing methods were compared. To reduce input variables and collinearity problems, three methods for variable selection were compared, including successive projections algorithm (SPA), genetic algorithm-partial least squares regression (GA-PLS), and competitive adaptive reweighted sampling (CARS). The selected variables were employed as the inputs of partial least square (PLS), back propagation-artificial neural networks (BP-ANN), and extreme learning machine (ELM) models. The best performance was achieved by BP-ANN models based on variables selected by CARS for all three chemical constituents. The values of rp2 (correlation coefficient of prediction) were 0.924, 0.927, 0.933, the values of RMSEP were 0.033, 0.018, 0.064 and the values of RPD were 3.667, 3.667, 2.891 for chlorogenic acid, luteoloside, and 3,5-O-dicaffeoylquinic acid, respectively. The results indicated that NIR spectroscopy combined with variables selection and multivariate calibration methods could be considered as a useful tool for rapid determination of chlorogenic acid, luteoloside, and 3,5-O-dicaffeoylquinic acid in Chrysanthemum.


Assuntos
Ácido Clorogênico/análogos & derivados , Ácido Clorogênico/análise , Chrysanthemum/química , Glucosídeos/análise , Luteolina/análise , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Algoritmos , Calibragem , Ácido Clorogênico/normas , Cromatografia Líquida de Alta Pressão/normas , Chrysanthemum/metabolismo , Glucosídeos/normas , Análise dos Mínimos Quadrados , Luteolina/normas , Espectroscopia de Luz Próxima ao Infravermelho/normas
6.
Int J Mol Sci ; 20(9)2019 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-31064052

RESUMO

Brown adipose tissue (BAT) may potentially be used in strategies for preventing lifestyle-related diseases. We examine evidence that near-infrared time-resolved spectroscopy (NIRTRS) is capable of estimating human BAT density (BAT-d). The parameters examined in this study are total hemoglobin [total-Hb]sup, oxygenated Hb [oxy-Hb]sup, deoxygenated Hb [deoxy-Hb]sup, Hb O2 saturation (StO2sup), and the reduced scattering coefficient in the supraclavicular region (µs'sup), where BAT deposits can be located; corresponding parameters in the control deltoid region are obtained as controls. Among the NIRTRS parameters, [total-Hb]sup and [oxy-Hb]sup show region-specific increases in winter, compared to summer. Further, [total-Hb]sup and [oxy-Hb]sup are correlated with cold-induced thermogenesis in the supraclavicular region. We conclude that NIRTRS-determined [total-Hb]sup and [oxy-Hb]sup are useful parameters for evaluating BAT-d in a simple, rapid, non-invasive manner.


Assuntos
Tecido Adiposo Marrom/fisiologia , Oxiemoglobinas/análise , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Tecido Adiposo Marrom/anatomia & histologia , Tecido Adiposo Marrom/diagnóstico por imagem , Adulto , Músculo Deltoide , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Tomografia por Emissão de Pósitrons/normas , Sensibilidade e Especificidade , Espectroscopia de Luz Próxima ao Infravermelho/normas , Termogênese
7.
Artigo em Inglês | MEDLINE | ID: mdl-30818218

RESUMO

For the modeling of near infrared spectroscopy (NIRS), the accuracy of the basic data, the stability of the spectra and the optimality of variables selection method were the important factors. In this paper, a novel optimization strategy for NIRS modeling was proposed, which was formed by data mean and ratio of absorbance to concentration (RATC) methods. The data mean method was aim to obtain accurate basic data and stable spectra, the RATC method was aim to select the optimal variables and compared with other variables selection methods (FiPLS, BiPLS, CC, UVE). The experimental subject was raw human plasma, with this novel optimization strategy, the predictive capability of NIRS model of its total protein (TP) content had been improved. At the same time, the public NIRS testing data (water, protein, oil, starch of corn and octane of gasoline) were used to verify the proposed variables selection method, and the predictive capability of these models of different parameters were also improved. To some extent, the optimization strategy of NIRS modeling provided theoretical supports for the development of protein content analyzer of NIRS and the quick determination of parameters of biologics and other materials.


Assuntos
Espectroscopia de Luz Próxima ao Infravermelho/métodos , Espectroscopia de Luz Próxima ao Infravermelho/normas , Absorção Fisico-Química , Proteínas Sanguíneas/análise , Calibragem , Gasolina/análise , Humanos , Modelos Químicos , Zea mays/química
8.
Food Chem ; 286: 297-306, 2019 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-30827610

RESUMO

Amylose content is an important determinant of rice quality. Accurate non-destructive determination of amylose content remains a primary challenge for the rice industry. Here, we analysed the accuracy of three models for the non-destructive determination of amylose content. The models were developed by combining near-infrared spectra, colour, and physicochemical information relative to 832 brown rice samples from ten varieties produced between 2009 and 2017 in various regions of Hokkaido, Japan. Models describing low and ordinary amylose varieties were developed individually, merged, and validated using production year samples (2016-2017) different from the calibration set (2009-2015). The resulting accuracy was suitable for industrial application. With standard error of prediction = 0.70% and ratio of performance deviation = 3.56, the combination of near-infrared spectra and physicochemical information produced the most robust model, enabling more precise rice quality screening at grain elevators.


Assuntos
Amilose/análise , Oryza/metabolismo , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Amilose/normas , Calibragem , Cor , Qualidade dos Alimentos , Espectroscopia de Luz Próxima ao Infravermelho/normas
9.
Eur J Appl Physiol ; 119(5): 1117-1125, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30771059

RESUMO

PURPOSE: Cerebral oxygenation as measured by near-infrared spectroscopy (NIRS) might be useful to discriminate between physiological and pathological responses after standing up in individuals with orthostatic hypotension. This study addressed the physiological sensitivity of the cerebral oxygenation responses as measured by NIRS to different types and speeds of postural changes in healthy adults and assessed the reliability of these responses. METHODS: Cerebral oxygenated hemoglobin (O2Hb), deoxygenated hemoglobin (HHb) and tissue saturation index (TSI) were measured bilaterally on the forehead of 15 healthy individuals (12 male, age range 18-27) using NIRS. Participants performed three repeats of sit to stand, and slow and rapid supine to stand movements. Responses were defined as the difference between mean, minimum and maximum O2Hb, HHb and TSI values after standing up and baseline. Test-retest, interobserver and intersensor reliabilities were addressed using intraclass correlation coefficients (ICCs). RESULTS: The minimum O2Hb response was most sensitive to postural changes and showed significant differences (- 4.09 µmol/L, p < 0.001) between standing up from sitting and supine position, but not between standing up at different speeds (- 0.31 µmol/L, p = 0.70). The minimum O2Hb response was the most reliable parameter (ICC > 0.6). CONCLUSIONS: In healthy individuals, NIRS-based cerebral oxygenation parameters are sensitive to postural change and discriminate between standing up from supine and sitting position with minimum O2Hb response as the most sensitive and reliable parameter. The results underpin the potential value for future clinical use of NIRS in individuals with orthostatic hypotension.


Assuntos
Encéfalo/metabolismo , Hipotensão Ortostática/fisiopatologia , Consumo de Oxigênio , Oxiemoglobinas/análise , Postura , Espectroscopia de Luz Próxima ao Infravermelho/normas , Adolescente , Adulto , Feminino , Humanos , Masculino , Distribuição Aleatória , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
10.
Neurocrit Care ; 30(1): 72-80, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30030667

RESUMO

BACKGROUND: Diffuse correlation spectroscopy (DCS) noninvasively permits continuous, quantitative, bedside measurements of cerebral blood flow (CBF). To test whether optical monitoring (OM) can detect decrements in CBF producing cerebral hypoxia, we applied the OM technique continuously to probe brain-injured patients who also had invasive brain tissue oxygen (PbO2) monitors. METHODS: Comatose patients with a Glasgow Coma Score (GCS) < 8) were enrolled in an IRB-approved protocol after obtaining informed consent from the legally authorized representative. Patients underwent 6-8 h of daily monitoring. Brain PbO2 was measured with a Clark electrode. Absolute CBF was monitored with DCS, calibrated by perfusion measurements based on intravenous indocyanine green bolus administration. Variation of optical CBF and mean arterial pressure (MAP) from baseline was measured during periods of brain hypoxia (defined as a drop in PbO2 below 19 mmHg for more than 6 min from baseline (PbO2 > 21 mmHg). In a secondary analysis, we compared optical CBF and MAP during randomly selected 12-min periods of "normal" (> 21 mmHg) and "low" (< 19 mmHg) PbO2. Receiver operator characteristic (ROC) and logistic regression analysis were employed to assess the utility of optical CBF, MAP, and the two-variable combination, for discrimination of brain hypoxia from normal brain oxygen tension. RESULTS: Seven patients were enrolled and monitored for a total of 17 days. Baseline-normalized MAP and CBF significantly decreased during brain hypoxia events (p < 0.05). Through use of randomly selected, temporally sparse windows of low and high PbO2, we observed that both MAP and optical CBF discriminated between periods of brain hypoxia and normal brain oxygen tension (ROC AUC 0.761, 0.762, respectively). Further, combining these variables using logistic regression analysis markedly improved the ability to distinguish low- and high-PbO2 epochs (AUC 0.876). CONCLUSIONS: The data suggest optical techniques may be able to provide continuous individualized CBF measurement to indicate occurrence of brain hypoxia and guide brain-directed therapy.


Assuntos
Pressão Arterial/fisiologia , Circulação Cerebrovascular/fisiologia , Hipóxia-Isquemia Encefálica/diagnóstico por imagem , Hipóxia-Isquemia Encefálica/fisiopatologia , Monitorização Neurofisiológica/métodos , Adulto , Lesões Encefálicas/diagnóstico por imagem , Lesões Encefálicas/fisiopatologia , Coma/diagnóstico por imagem , Coma/fisiopatologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Neuroimagem/métodos , Neuroimagem/normas , Monitorização Neurofisiológica/normas , Imagem Óptica/métodos , Imagem Óptica/normas , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Espectroscopia de Luz Próxima ao Infravermelho/normas
11.
Dev Psychobiol ; 61(3): 430-443, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30588618

RESUMO

Much of what is known about the course of auditory learning in following cochlear implantation is based on behavioral indicators that users are able to perceive sound. Both prelingually deafened children and postlingually deafened adults who receive cochlear implants display highly variable speech and language processing outcomes, although the basis for this is poorly understood. To date, measuring neural activity within the auditory cortex of implant recipients of all ages has been challenging, primarily because the use of traditional neuroimaging techniques is limited by the implant itself. Functional near-infrared spectroscopy (fNIRS) is an imaging technology that works with implant users of all ages because it is non-invasive, compatible with implant devices, and not subject to electrical artifacts. Thus, fNIRS can provide insight into processing factors that contribute to variations in spoken language outcomes in implant users, both children and adults. There are important considerations to be made when using fNIRS, particularly with children, to maximize the signal-to-noise ratio and to best identify and interpret cortical responses. This review considers these issues, recent data, and future directions for using fNIRS as a tool to understand spoken language processing in children and adults who hear through a cochlear implant.


Assuntos
Córtex Auditivo/fisiopatologia , Implantes Cocleares , Surdez/fisiopatologia , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Percepção da Fala/fisiologia , Adulto , Córtex Auditivo/diagnóstico por imagem , Criança , Surdez/diagnóstico por imagem , Humanos , Espectroscopia de Luz Próxima ao Infravermelho/normas
12.
Talanta ; 189: 233-240, 2018 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-30086911

RESUMO

The performance of three portable NIR spectrometers was compared by analysing the total antioxidant capacity (TAC) of different species of gluten-free grains. TAC is often used to evaluate the quality of foods and was determined using Folin-Ciocalteu measurements and used as reference data for establishing PLS-R models with NIR data. NIRS enables fast and non-invasive measurements. The microPhazir RX and the MicroNIR 2200 are broadly used in chemical and pharmaceutical industries, whereas SCiO is a pocket-sized, consumer-oriented spectrometer. The devices work in different regions of the NIR spectrum and their performances was compared using statistical parameters. 77 samples were measured and analysed using the software The Unscrambler X, as well as SCiO-Lab. All models established were cross- and test set validated. The multivariate data processing using The Unscrambler X yielded similar results as SCiO-Lab. The best model was established for non-milled samples measured with the MicroNIR 2200 and analysed using The Unscrambler X.


Assuntos
Antioxidantes/análise , Grão Comestível/química , Espectroscopia de Luz Próxima ao Infravermelho/instrumentação , Antioxidantes/química , Glutens/análise , Análise Multivariada , Padrões de Referência , Espectroscopia de Luz Próxima ao Infravermelho/normas
13.
Eur J Anaesthesiol ; 35(12): 907-910, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30020143

RESUMO

BACKGROUND: Cerebral near-infrared spectroscopy (NIRS) of tissue oxygen saturation is claimed to be a surrogate marker for global cerebral perfusion. Increasingly, NIRS target-based therapy has been used during cardiac surgery in the hope of decreasing the incidence of adverse neurological outcome. OBJECTIVES: We report NIRS values for some common vegetables and faculty at a world-class medical institution. DESIGN: Observational nonblinded study. SETTING: Single tertiary care institution and local urban vegetable market. PARTICIPANTS: Five yams (Dioscorea cayenensis), five courgettes (Cucurbita pepo) and five butternut squashes (Cucurbita moschata) were studied. Five cardiothoracic surgeons and anaesthesiologists were the control group. INTERVENTIONS: None. MAIN OUTCOME MEASURES: NIRS value of each species. RESULTS: Mean NIRS value for the control group was 71% [95% confidence interval (CI) 68 to 74] and was similar to that of the yellow squashes [75% (95% CI 74 to 76)]. These values were significantly greater than the NIRS measurements of both the butternut squash and yam [63% (95% CI 62 to 64) and 64% (95% CI 63 to 65), respectively, P < 0.01]. CONCLUSION: Commonly eaten vegetables have NIRS measurements similar to those seen in healthy humans.


Assuntos
Encéfalo/metabolismo , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Verduras/metabolismo , Feminino , Humanos , Masculino , Oximetria/métodos , Oximetria/normas , Espectroscopia de Luz Próxima ao Infravermelho/normas
14.
Appl Spectrosc ; 72(9): 1362-1370, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29855195

RESUMO

For sustainable utilization of raw materials and environmental protection, the recycling of the most common polymers-polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polyvinyl chloride (PVC), and polystyrene (PS)-is an extremely important issue. In the present communication, the discrimination performance of the above polymer commodities based on their near-infrared (NIR) spectra measured with four real handheld (<200 g) spectrometers based on different monochromator principles were investigated. From a total of 43 polymer samples, the diffuse reflection spectra were measured with the handheld instruments. After the original spectra were pretreated by second derivative and standard normal variate (SNV), principal component analysis (PCA) was applied and unknown samples were tested by soft independent modeling of class analogies (SIMCA). The results show that the five polymer commodities cluster in the score plots of their first three principal components (PCs) and, furthermore, samples in calibration and test sets can be correctly identified by SICMA. Thus, it was concluded that on the basis of the NIR spectra measured with the handheld spectrometers the SIMCA analysis provides a suitable analytical tool for the correct assignment of the type of polymer. Because the mean distance between clusters in the score plot reflects the discrimination capability for each polymer pair the variation of this parameter for the spectra measured with the different handheld spectrometers was used to rank the identification performance of the five polymer commodities.


Assuntos
Polímeros , Espectroscopia de Luz Próxima ao Infravermelho , Calibragem , Polímeros/análise , Polímeros/química , Polímeros/classificação , Análise de Componente Principal , Espectroscopia de Luz Próxima ao Infravermelho/instrumentação , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Espectroscopia de Luz Próxima ao Infravermelho/normas
15.
J Neural Eng ; 15(4): 045001, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29616976

RESUMO

OBJECTIVE: The statistical analysis of functional near infrared spectroscopy (fNIRS) data based on the general linear model (GLM) is often made difficult by serial correlations, high inter-subject variability of the hemodynamic response, and the presence of motion artifacts. In this work we propose to extract information on the pattern of hemodynamic activations without using any a priori model for the data, by classifying the channels as 'active' or 'not active' with a multivariate classifier based on linear discriminant analysis (LDA). APPROACH: This work is developed in two steps. First we compared the performance of the two analyses, using a synthetic approach in which simulated hemodynamic activations were combined with either simulated or real resting-state fNIRS data. This procedure allowed for exact quantification of the classification accuracies of GLM and LDA. In the case of real resting-state data, the correlations between classification accuracy and demographic characteristics were investigated by means of a Linear Mixed Model. In the second step, to further characterize the reliability of the newly proposed analysis method, we conducted an experiment in which participants had to perform a simple motor task and data were analyzed with the LDA-based classifier as well as with the standard GLM analysis. MAIN RESULTS: The results of the simulation study show that the LDA-based method achieves higher classification accuracies than the GLM analysis, and that the LDA results are more uniform across different subjects and, in contrast to the accuracies achieved by the GLM analysis, have no significant correlations with any of the demographic characteristics. Findings from the real-data experiment are consistent with the results of the real-plus-simulation study, in that the GLM-analysis results show greater inter-subject variability than do the corresponding LDA results. SIGNIFICANCE: The results obtained suggest that the outcome of GLM analysis is highly vulnerable to violations of theoretical assumptions, and that therefore a data-driven approach such as that provided by the proposed LDA-based method is to be favored.


Assuntos
Interpretação Estatística de Dados , Hemodinâmica/fisiologia , Modelos Teóricos , Espectroscopia de Luz Próxima ao Infravermelho/normas , Humanos , Análise Multivariada , Reprodutibilidade dos Testes , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Espectroscopia de Luz Próxima ao Infravermelho/estatística & dados numéricos
16.
Neuroimage ; 176: 321-353, 2018 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-29698730

RESUMO

The robust characterization of real-time brain activity carries potential for many applications. However, the contamination of measured signals by various instrumental, environmental, and physiological sources of noise introduces a substantial amount of signal variance and, consequently, challenges real-time estimation of contributions from underlying neuronal sources. Functional near infra-red spectroscopy (fNIRS) is an emerging imaging modality whose real-time potential is yet to be fully explored. The objectives of the current study are to (i) validate a time-dependent linear model of hemodynamic responses in fNIRS, and (ii) test the robustness of this approach against measurement noise (instrumental and physiological) and mis-specification of the hemodynamic response basis functions (amplitude, latency, and duration). We propose a linear hemodynamic model with time-varying parameters, which are estimated (adapted and tracked) using a dynamic recursive least square algorithm. Owing to the linear nature of the activation model, the problem of achieving robust convergence to an accurate estimation of the model parameters is recast as a problem of parameter error stability around the origin. We show that robust convergence of the proposed method is guaranteed in the presence of an acceptable degree of model misspecification and we derive an upper bound on noise under which reliable parameters can still be inferred. We also derived a lower bound on signal-to-noise-ratio over which the reliable parameters can still be inferred from a channel/voxel. Whilst here applied to fNIRS, the proposed methodology is applicable to other hemodynamic-based imaging technologies such as functional magnetic resonance imaging.


Assuntos
Encéfalo/diagnóstico por imagem , Encéfalo/fisiologia , Neuroimagem Funcional/normas , Modelos Teóricos , Acoplamento Neurovascular/fisiologia , Espectroscopia de Luz Próxima ao Infravermelho/normas , Simulação por Computador , Neuroimagem Funcional/métodos , Humanos , Razão Sinal-Ruído , Espectroscopia de Luz Próxima ao Infravermelho/métodos
17.
Hum Brain Mapp ; 39(7): 2710-2724, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29516587

RESUMO

Functional near-infrared spectroscopy (fNIRS) is an emerging technique for the assessment of functional activity of the cerebral cortex. Recently fNIRS was also envisaged as a novel neuroimaging approach for measuring the auditory cortex activity in the field of in auditory diagnostics. This study aimed to investigate differences in brain activity related to spatially presented sounds with different intensities in 10 subjects by means of functional near-infrared spectroscopy (fNIRS). We found pronounced cortical activation patterns in the temporal and frontal regions of both hemispheres. In contrast to these activation patterns, we found deactivation patterns in central and parietal regions of both hemispheres. Furthermore our results showed an influence of spatial presentation and intensity of the presented sounds on brain activity in related regions of interest. These findings are in line with previous fMRI studies which also reported systematic changes of activation in temporal and frontal areas with increasing sound intensity. Although clear evidence for contralaterality effects and hemispheric asymmetries were absent in the group data, these effects were partially visible on the single subject level. Concluding, fNIRS is sensitive enough to capture differences in brain responses during the spatial presentation of sounds with different intensities in several cortical regions. Our results may serve as a valuable contribution for further basic research and the future use of fNIRS in the area of central auditory diagnostics.


Assuntos
Percepção Auditiva/fisiologia , Córtex Cerebral/fisiologia , Lateralidade Funcional/fisiologia , Neuroimagem Funcional/métodos , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Adulto , Córtex Cerebral/diagnóstico por imagem , Feminino , Neuroimagem Funcional/normas , Humanos , Masculino , Espectroscopia de Luz Próxima ao Infravermelho/normas , Adulto Jovem
18.
J Sci Food Agric ; 98(11): 4253-4267, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29424423

RESUMO

BACKGROUND: Winter pea (Pisum sativum L.) grows well in a wide geographic region, both as a forage and cover crop. Understanding the quality constituents of this crop is important for both end uses; however, analysis of quality constituents by conventional wet chemistry methods is laborious, slow and costly. Near infrared reflectance spectroscopy (NIRS) is a precise, accurate, rapid and cheap alternative to using wet chemistry for estimating quality constituents. We developed and validated NIRS calibration models for constituent analysis of this crop. RESULTS: Of the 11 constituent models developed, nine constituents including moisture, dry-matter, total-nitrogen, crude protein, acid detergent fiber, neutral detergent fiber, AD-lignin, cellulose and non-fibrous carbohydrate had low standard errors and a high coefficient of determination (R2 = 0.88-0.98; 1 - VR, which is the coefficient of determination during cross-validation = 0.77-0.92) for both calibration and cross-validation, indicating their potential for quantitative predictability. The calibration models for ash (R2 = 0.65; 1 - VR = 0.46) and hemicellulose (R2 = 0.75; 1 - VR = 0.50) also appeared to be adequate for qualitative screening. Predictions of an independent validation set yielded reliable agreement between the NIRS predicted values and the reference values with low standard error of prediction (SEP), low bias, high coefficient of determination (r2 = 0.82-0.95), high ratios of performance to deviation (RPD = SD/SEP; 2.30-3.85) and high ratios of performance to interquartile distance (RPIQ = IQ/SEP; 2.57-7.59) for all 11 constituents. CONCLUSION: Precise, accurate and rapid analysis of winter pea for major forage and cover crop quality constituents can be performed at a low cost using the NIRS calibration models developed. © 2018 Society of Chemical Industry.


Assuntos
Ervilhas/química , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Calibragem , Celulose/análise , Frutas/química , Lignina/análise , Nitrogênio/análise , Controle de Qualidade , Espectroscopia de Luz Próxima ao Infravermelho/normas
19.
Sci Rep ; 8(1): 1242, 2018 01 19.
Artigo em Inglês | MEDLINE | ID: mdl-29352217

RESUMO

This pilot study aimed to investigate the utility of near-infrared spectroscopy/indocyanine green (NIRS/ICG) for examining patients with occlusive cerebrovascular disease. Twenty-nine patients with chronic-stage atherosclerotic occlusive cerebrovascular disease were included. The patients were monitored using NIRS at the bedside. Using ICG time-intensity curves, the affected-to-unaffected side ratios were calculated for several parameters, including the maximum ICG concentration (ΔICGmax), time to peak (TTP), rise time (RT), and blood flow index (BFI = ΔICGmax/RT), and were compared to the affected-to-unaffected side ratios of the regional cerebral blood flow (rCBF) and regional oxygen extraction fraction (rOEF) obtained using positron emission tomography with 15O-labeled gas. The BFI ratio showed the best correlation with the rCBF ratio among these parameters (r = 0.618; P = 0.0004), and the RT ratio showed the best correlation with the rOEF ratio (r = 0.593; P = 0.0007). The patients were further divided into reduced rCBF or elevated rOEF groups, and the analysis revealed significant related differences. The present results advance the measurement of ICG kinetics using NIRS as a useful tool for the detection of severely impaired perfusion with reduced rCBF or elevated rOEF. This method may be applicable as a monitoring tool for patients with acute ischemic stroke.


Assuntos
Aterosclerose/diagnóstico por imagem , Circulação Cerebrovascular , Transtornos Cerebrovasculares/diagnóstico por imagem , Testes Imediatos/normas , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Idoso , Aterosclerose/complicações , Transtornos Cerebrovasculares/etiologia , Feminino , Humanos , Verde de Indocianina , Masculino , Pessoa de Meia-Idade , Espectroscopia de Luz Próxima ao Infravermelho/normas
20.
Med. oral patol. oral cir. bucal (Internet) ; 23(1): e98-e104, ene. 2018. ilus, tab
Artigo em Inglês | IBECS | ID: ibc-170311

RESUMO

Background: Avoidance from palatal blood vessel rupture is a major concern during the palatal soft tissue graft surgery. There is no defined chair-side and case-specific palatal blood vessel detection approach to facilitate the harvesting process. The objective of this pilot study is to assess the feasibility of a near-infrared vein visualization system in the screening process of palatal blood vessels. Material and Methods: An extraoral vein visualization device (AccuVein AV400) was applied to a total of 304 hemi-maxilla of 152 individuals by two blind examiners. The study groups were classified according to their maximum inter-incisal measurements. The distances between the coronal border of the vessel image and the mid-palatal gingival margins of the adjacent teeth were measured and in each group. The correlations among the measurements were evaluated within groups. Results: The blood vessel to the adjacent teeth measurements exhibited no statistical difference between both examiners in all subjects (p<0.001). Correlations between the examiners gradually increased in all groups as the mouth opening rates of the subjects were increased (p<0.001). Conclusions: In the current state, screening of the palatal blood vessels via near-infrared vein visualization technology seems to be not suitable for every individual due to the restrictive effect of mouth opening. However, the promising results of this preliminary study demonstrated increasing consistency between the measurements of the examiners as the inter-incisal distance increase which emphasized the need an intraoral version of the device. Considering the lack of local decision-making technology for the detection of palatal blood vessels, further studies are required for development and optimization of these systems (AU)


No disponible


Assuntos
Humanos , Vasos Sanguíneos/efeitos da radiação , Administração Sanitária , Palato/efeitos da radiação , Veias/diagnóstico por imagem , Complicações Intraoperatórias/diagnóstico por imagem , Espectroscopia de Luz Próxima ao Infravermelho/instrumentação , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Espectroscopia de Luz Próxima ao Infravermelho/normas , Protocolos Clínicos
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