Near-infrared spectroscopy has been used for measurement of changes in cerebr al Hb concentrations in infants to study cerebral oxygenation and hemodynamics. In this study, measurements by time-resolved spectroscopy (...Near-infrared spectroscopy has been used for measurement of changes in cerebr al Hb concentrations in infants to study cerebral oxygenation and hemodynamics. In this study, measurements by time-resolved spectroscopy (TRS) were performed in 22 neonates to estimate the values of light absorption coefficient and reduce d scattering coefficient (μ’s), cerebral Hb oxygen saturation (Sco2), cerebral blood volume (CBV), and differential path-length factor (DPF), and the relatio nships between postconceptional age and μ’s, Sco2, CBV, and DPF were investigated. A portable three-wavelength TRS system with a probe attached to the head of the neonate was used. The mean μ’s values at 761, 795, and 835 nm in neonates were estimated to be (mean ±SD ) 6.46 ±1.21, 5.90 ±1.15 and 6.40 ±1.16/cm, respectively. There was a signifi cant positive relationship between postconceptional age and μ’s at those three wavelengths. The mean Sco2 value was calculated to be 70.0 ±4.6%, and postcon ceptional age and Sco2 showed a negative linear relationship. The mean value of CBV was 2.31 ±0.56 mL/100 g. There was a significant positive relationship betw een postconceptional age and CBV. The mean DPF values at 761, 795, and 835 nm we re estimated to be 4.58 ±0.41, 4.64 ±0.46, and 4.31 ±0.42, respectively. Ther e was no relationship between postconceptional age and DPF at those three wavele ngths. The results demonstrated that our near-infrared TRS method can be used t o monitor μ’s, Sco2, CBV, and DPF in the neonatal brain at the bedside in an i ntensive care unit.展开更多
To develop nondestructive acidity prediction for intact Fuji apples, the potential of Fourier transform near infrared (FT-NIR) method with fiber optics in interactance mode was investigated. Interactance in the 800 nm...To develop nondestructive acidity prediction for intact Fuji apples, the potential of Fourier transform near infrared (FT-NIR) method with fiber optics in interactance mode was investigated. Interactance in the 800 nm to 2619 nm region was measured for intact apples, harvested from early to late maturity stages. Spectral data were analyzed by two multivariate calibra- tion techniques including partial least squares (PLS) and principal component regression (PCR) methods. A total of 120 Fuji apples were tested and 80 of them were used to form a calibration data set. The influences of different data preprocessing and spectra treatments were also quantified. Calibration models based on smoothing spectra were slightly worse than that based on derivative spectra, and the best result was obtained when the segment length was 5 nm and the gap size was 10 points. Depending on data preprocessing and PLS method, the best prediction model yielded correlation coefficient of determination (r2) of 0.759, low root mean square error of prediction (RMSEP) of 0.0677, low root mean square error of calibration (RMSEC) of 0.0562. The results indicated the feasibility of FT-NIR spectral analysis for predicting apple valid acidity in a nondestructive way.展开更多
文摘Near-infrared spectroscopy has been used for measurement of changes in cerebr al Hb concentrations in infants to study cerebral oxygenation and hemodynamics. In this study, measurements by time-resolved spectroscopy (TRS) were performed in 22 neonates to estimate the values of light absorption coefficient and reduce d scattering coefficient (μ’s), cerebral Hb oxygen saturation (Sco2), cerebral blood volume (CBV), and differential path-length factor (DPF), and the relatio nships between postconceptional age and μ’s, Sco2, CBV, and DPF were investigated. A portable three-wavelength TRS system with a probe attached to the head of the neonate was used. The mean μ’s values at 761, 795, and 835 nm in neonates were estimated to be (mean ±SD ) 6.46 ±1.21, 5.90 ±1.15 and 6.40 ±1.16/cm, respectively. There was a signifi cant positive relationship between postconceptional age and μ’s at those three wavelengths. The mean Sco2 value was calculated to be 70.0 ±4.6%, and postcon ceptional age and Sco2 showed a negative linear relationship. The mean value of CBV was 2.31 ±0.56 mL/100 g. There was a significant positive relationship betw een postconceptional age and CBV. The mean DPF values at 761, 795, and 835 nm we re estimated to be 4.58 ±0.41, 4.64 ±0.46, and 4.31 ±0.42, respectively. Ther e was no relationship between postconceptional age and DPF at those three wavele ngths. The results demonstrated that our near-infrared TRS method can be used t o monitor μ’s, Sco2, CBV, and DPF in the neonatal brain at the bedside in an i ntensive care unit.
基金Projects (Nos. 30370371 and 60468002) supported by the NationalNatural Science Foundation of China
文摘To develop nondestructive acidity prediction for intact Fuji apples, the potential of Fourier transform near infrared (FT-NIR) method with fiber optics in interactance mode was investigated. Interactance in the 800 nm to 2619 nm region was measured for intact apples, harvested from early to late maturity stages. Spectral data were analyzed by two multivariate calibra- tion techniques including partial least squares (PLS) and principal component regression (PCR) methods. A total of 120 Fuji apples were tested and 80 of them were used to form a calibration data set. The influences of different data preprocessing and spectra treatments were also quantified. Calibration models based on smoothing spectra were slightly worse than that based on derivative spectra, and the best result was obtained when the segment length was 5 nm and the gap size was 10 points. Depending on data preprocessing and PLS method, the best prediction model yielded correlation coefficient of determination (r2) of 0.759, low root mean square error of prediction (RMSEP) of 0.0677, low root mean square error of calibration (RMSEC) of 0.0562. The results indicated the feasibility of FT-NIR spectral analysis for predicting apple valid acidity in a nondestructive way.
