A new strategy for quantitative analysis of a major clinical biochemical indicator called glycated hemoglobin (HbA1c) was proposed. The technique was based on the simultaneous near-infrared (NIR) spectral determination of hemoglobin (Hb) and absolute HbA1c content (Hb • HbA1c) in human hemolysate samples. Wavelength selections were accomplished using the improved moving window partial least square (MWPLS) method for stability. Each model was established using an approach based on randomness, similarity, and stability to obtain objective, stable, and practical models. The optimal wavebands obtained using MWPLS were 958 to 1036 nm for Hb and 1492 to 1858 nm for Hb • HbA1c, which were within the NIR overtone region. The validation root mean square error and validation correlation coefficients of prediction (V-SEP, V-R P ) were 3.4 g L -1 and 0.967 for Hb, respectively, whereas the corresponding values for Hb • HbA1c were 0.63 g L -1 and 0.913. The corresponding V-SEP and V-R P were 0.40% and 0.829 for the relative percentage of HbA1c. The experimental results confirm the feasibility for the quantification of HbA1c based on simultaneous NIR spectroscopic analyses of Hb and Hb • HbA1c.
Teicoplanin (TCP) is an important lipoglycopeptide antibiotic produced by fermenting Actinoplanes teichomyceticus. The change in TCP concentration is important to measure in the fermentation process. In this study, a reagent-free and rapid quantification method for TCP in the TCP–Tris–HCl mixture samples was developed using near-infrared (NIR) spectroscopy by focusing our attention on the fermentation process for TCP. The absorbance optimization (AO) partial least squares (PLS) was proposed and integrated with the moving window (MW) PLS, which is called AO–MW–PLS method, to select appropriate wavebands. A model set that includes various wavebands that were equivalent to the optimal AO–MW–PLS waveband was proposed based on statistical considerations. The public region of all equivalent wavebands was just one of the equivalent wavebands. The obtained public regions were 1540–1868[Formula: see text]nm for TCP and 1114–1310[Formula: see text]nm for Tris. The root-mean-square error and correlation coefficient for leave-one-out cross validation were 0.046[Formula: see text]mg mL[Formula: see text] and 0.9998[Formula: see text]mg mL[Formula: see text] for TCP, and 0.235[Formula: see text]mg mL[Formula: see text] and 0.9986[Formula: see text]mg mL[Formula: see text] for Tris, respectively. All the models achieved highly accurate prediction effects, and the selected wavebands provided valuable references for designing specialized spectrometers. This study provided a valuable reference for further application of the proposed methods to TCP fermentation broth and to other spectroscopic analysis fields.
The selection of stable wavebands for the near-infrared (NIR) spectroscopic analysis of total nitrogen (TN) in soil was accomplished by using an improved moving window partial least squares (MWPLS) method. A new modeling approach was performed based on randomness, similarity and stability, which produced an objective, stable and practical model. Based on the MWPLS method, a search was in the overall scanning region from 400 to 2498 nm, and the optimal waveband was identified to be 1424 to 2282 nm. A model space that includes 41 wavebands that are equivalent to the optimal waveband was then proposed. The public range of the 41 equivalent optimal wavebands was 1590 to 1870 nm, which contained sufficient TN information. The wavebands of 1424 to 2282 nm, 1590 to 1870 nm, and the long-NIR region 1100 to 2498 nm all achieved satisfactory validation effects. However, the public waveband of 1590 to 1870 nm had only a minimum number of wavelengths, which significantly reduced the method complexity. Various equivalent wavebands serve as guidelines for designing spectroscopic instruments. These wavebands could address the restrictions of position and the number of wavelengths in instrument design.
The Savitzky–Golay (SG) method and moving-window waveband screening are applied to a coupling model of principal component (PCA) and linear discriminant analyses (LDA).
A rapid quantitative analysis method of glucose in aqueous solution was established by using the FTIR/ATR spectroscopy, partial least squares (PLS) regression and Savitzky-Golay (SG) smoothing method. Based on the prediction effect of the optimal single wavenumber model, calibration set and prediction set were divided. By extending the number of smoothing points and the degree of polynomial, 483 smooth modes were calculated. The PLS models corresponding to all combinations of 483 SG smoothing modes and 1-40 PLS factor were established respectively. The optimal smoothing parameters were the first order derivative smoothing, 5 or 6 degree polynomial, 63 smoothing points, the optimal PLS factor, root mean squared error of predication (RMSEP), correlation coefficient of predication (R P ) and relative root mean squared error of predication (RRMSEP) were 3, 0.3729 (mmol/L), 0.9995 and 2.48% respectively, which was obviously superior to the direct PLS model without SG smoothing and the optimal SG smoothing model within 25 smoothing points (the original smoothing method). This demonstrates that the extending of SG smoothing modes and large-scale simultaneous optimization selection of SG smoothing parameters and PLS factor was all very necessary, and can be effectively applied to the model optimization of FTIR/ATR spectroscopy analysis.
Equidistant combination multiple linear regression (EC-MLR) for the quasi-continuous wavelength selection of spectroscopic analysis was proposed and successfully applied to the reagent-free determination of soil organic matter with near-infrared spectroscopy. For comparison, the continuous-mode moving window partial least squares (MWPLS) and the discrete-mode successive projections algorithm (SPA) were improved by considering the stability and applied to the same analysis object as well. All methods exhibited good effect, but the modeling accuracy, stability, and validation effect of EC-MLR were better than that of the other two methods. Compared with MWPLS, the optimal EC-MLR model contained only 16 wavelengths, and method complexity was substantially reduced. Compared with SPA-MLR, the optimal EC-MLR model could easily undergo spectral preprocessing to improve predictive capability. Moreover, appropriate equidistant discrete wavelength combination with EC-MLR corresponded to the spectral absorption band with proper resolution and can effectively overcome co-linearity interruption for the MLR model. Thus, the EC-MLR method has great potential in practical application and instrument design.
Sludge bio-membrane nitrogen and phosphorus removal system was used to enrich denitrifying phosphorus bacteria(DPB).Plate separation and PCR-DGGE technology were applied to monitor the diversity of bacteria.The results show that before the enrichment,isolated micro-organisms are mainly seven kinds of bacteria including Corynebacterium sp.,Acinetobacter sp.,Pseudomonas sp.,Enterobacteriaceae sp.,Moraxella sp.,Staphylococcus sp.and Paracoccus sp.,seven kinds of bacteria are isolated by the plate separation.After enrichment four kinds of main bacteria i.e.,Acinetobacter sp.,Pseudomonas sp.,Enterobacteriaceae sp.,and Paracoccus sp.,are found.The species of bacteria are reduced after enrichment and DPB in SB system are different in the SBR.Using PCR-DGGE to investigate bacteria,Flavobacterium sp.,Alcaligenes sp.,Paracoccus sp.,Janthinobacterium sp.and Erythrobacter sp.are mainly five kinds of bacteria before enrichment,but only three kinds of bacteria i.e.,Alcaligenes sp.,Paracoccus sp.,and Janthinobacterium sp.are remained after enrichment.Paracoccus sp.is the only DPB which is confirmed by two methods.Proteobacteria sp.dominates the denitrifying phosphorus bacteria when PCR-DGGE and 16S rDNA clone method are used to analyze the diversity of bacteria.
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