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An electrochemical biosensor was prepared for nucleic acid-based hantavirus detection using a Cu-based metal-organic framework (CuMOF) as a signal tag. The CuMOF was synthesized by the solvothermal method and then covalently bonded with signal DNA (sDNA) probes. The Au nanoparticles and reduced graphene oxide composite were deposited on the electrode surface by electroreduction as support substrate and was then functionalized with capture DNA (cDNA) probes by self-assembly. Through the complementary base pairing, the target DNA (tDNA) fragment of hantavirus hybridized with the cDNA and the sDNA in a sandwich-type format. The tDNA was detected according to the current signal of the CuMOF catalyzed reaction using o-phenylenediamine as redox substrate. The peak current of the biosensor at − 0.55 V increased linearly in proportion to the logarithmic value of the tDNA concentration from 10−15 to 10−9 mol/L, with a detection limit of 0.74 × 10−15 mol/L. Moreover, the proposed biosensor was successfully applied to detect hantavirus and was able to distinguish hantavirus from other arboviruses.

The crystallization behavior and microstructure of a series of Dy 3 + /Tb 3 + doped aluminoborosilicate (ABS) magneto-optical glass was investigated using differential scanning calorimetry (DSC), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The apparent crystallization activation energy ( E g ) and the kinetic properties at the corresponding glass transition temperature ( T g ) were studied as a function of Dy 3 + /Tb 3 + concentration. The results showed that the glass matrix precipitated Al 3 Tb(BO 3 ) 4 and TbBO 3 crystals when subjected to heat treatment at 852.8 and 902.6 °C, respectively. The crystallization activation energy of these two crystalline phases (Al 3 Tb(BO 3 ) 4 and TbBO 3 ) was E p1 = 993.3 kJ/mol and E p2 = 544.97 kJ/mol, respectively. The average crystallization index was 0.5 and 0.8, respectively. By applying the Kissinger equation to the parameterized crystallization behavior, the calculated phase transition activation energy was determined to be 420.18 kJ/mol. The parameterized crystallization behavior of this particular ABS magneto-optical glass can be used to avoid the deterioration of magneto-optical properties due to the crystallization of glass matrix.

To produce manno-oligosaccharides from cassia gum, a mutated glycoside hydrolase family 134 β-mannanase gene (mRmMan134A) from Rhizopus microsporus var. rhizopodiformis F518 was expressed in Pichia pastoris and a high expression level (3680 U mL−1) was obtained through high cell density fermentation. mRmMan134A exhibited maximum activity at pH 5.5 and 50 °C. It was then subjected to hydrolyze cassia gum with 70.6% of overall yield of manno-oligosaccharides. From the hydrolysate, seven components (F1–F7) were separated and identified as mannose, mannobiose, galactose, mannotriose, mannotetraose, 61-α- d -galactosyl-β- d -mannobiose, and mannopentaose, respectively. According to in vitro fermentation, the manno-oligosaccharides were able to promote the growth of three Bifidobacterium strains and six Lactobaillus strains with 3.0-fold increment in culture absorbance, and these strains preferred manno-oligosaccharides with degree of polymerization (DP) 2–3 rather than those with DP 4–5. Novel manno-oligosaccharides from cassia gum with promising prebiotic activity were provided in the present study.

Hydroxyapatite luminescent nanocrystallines doped with 6 mol.% Tb3+ (Tb-HA) were prepared via chemical deposition method and calcined at different temperature, and the effects of calcinations temperature on the luminescence intensity and fluorescent lifetime were studied. TEM image of Tb-HA revealed that the shape of nanocrystallines changed from needle-like to short rod-like and sphere-like with the increase of calcinations temperature; while the particles sizes decreased from 190 nm to 110 nm. The crystallinity degree increased. The typical emission peaks attributed to Tb3+ ions were observed in emission spectra of 6 mol.% Tb-HA under 378 nm excitation. The luminescent intensity of Tb-HA, which showed the fluorescence quenching, firstly enhanced and then decreased at 700 °C; while the fluorescent lifetime increased firstly and then decreased after 600 °C. Furthermore, the ratio of intensity between 545 nm and 490 nm corresponding to electric-dipole and magnetic-dipole transition (IR: IO) increases firstly and then decreases, which revealed that the proportion of substitute type and site of Ca2+ ions by Tb3+ ions were helpful to realize the substitute process and functional structure design.

Hyperspectral imaging at visible and short near infrared (VIS/SNIR) region has been used to estimate the pigment content of leaves. A complicating feature of measurements with any hyperspectral imaging methodology is the large amount of information generated during the measurement process. In this paper we discuss the identification of the desirable information using independent component analysis (ICA). After hyperspectral image acquisition and pre-processing, the average spectra obtained from the region of interest (ROI) in cucumber leaves were used for model development. Additionally a multi-linear regression model was developed for the prediction of cucumber leaf chlorophyll content. When compared with normal principal component analysis (PCA), the ICA multi-linear regression model provided improved estimates. When the calibration models were applied to an independent validation set, chlorophyll content was reasonably well predicted with a high correlation (r2 = 0.774). Depending on the sample, the technique enabled the identification and characterization of the relative content of various chlorophyll types that were distributed within the cucumber leaves. Typically low levels of chlorophyll at leaf margins and higher levels along main vein regions were identified. Our results indicate that hyperspectral imaging exhibits considerable promise for predicting pigments within cucumber leaves and furthermore can be applied non-destructively and in situ to living plant samples.

The feasibility of using the efficient selection wavelength regions in FT-NIR for a rapid and conclusive determination of fruit inner qualities such as soluble solid content (SSC) of apples was investigated. An apple's NIRS acquisition device was developed in this study. With this device, the apple was rolling while collecting the NIR spectroscopy. Graphically-oriented local multivariate calibration modeling procedures called interval partial least-squares (iPLS), backward interval partial least-squares (BiPLS), forward interval partial least-squares (FiPLS), genetic algorithm interval partial least-squares (GA-iPLS) and genetic algorithm partial least-squares (GA-PLS) were applied to select the efficient spectral regions that provide the lowest prediction error, in comparison to the full-spectrum model. The optimal combinations of 12 spectral intervals among 40 intervals which selected by BiPLS yielded a good result (RMSEC = 0.39286, r c = 0.953, RMSEP = 0.4531, r p = 0.924), and the optimal combinations of 14 spectral intervals among 40 intervals which selected by FiPLS also yielded good results (RMSEC = 0.4027, r c = 0.948, RMSEP = 0.4424, r p = 0.927). The intervals selected by BiPLS were not the same with those selected by FiPLS, due to different algorithms employed in these two methods. The five intervals selected by GA-iPLS which contained 360 variables were used as calibration set in GA-PLS model. 45 variables were selected in the best prediction ability of the GA-PLS models (RMSEP = 0.414). These procedures allow the simultaneous determination of other internal quality of fruits.

Design and fabrication of an ammonia sensor operating at room temperature based on pigment-sensitized TiO2 films was described. TiO2 was prepared by sol–gel method and deposited on glass slides containing gold electrodes. Then, the film immersed in a 2.5 × 10−4 M ethanol solution of cyanidin to absorb the pigment. The hybrid organic–inorganic formed film here can detect ammonia reversibly at room temperature. The relative change resistance of the films at a potential difference of 1.5 V is determined when the films are exposed to atmospheres containing ammonia vapors with concentrations over the range 10–50 ppm. The relative change resistance, S, of the films increased almost linearly with increasing concentrations of ammonia (r = 0.92). The response time to increasing concentrations of the ammonia is about 180–220 s, and the corresponding values for decreasing concentrations 240–270 s. At low humidity, ammonia could be ionized by the cyanidin on the TiO2 film and thereby decrease in the proton concentration at the surface. Consequently, more positively charged holes at the surface of the TiO2 have to be extracted to neutralize the adsorbed cyanidin and water film. The resistance response to ammonia of the sensors was nearly independent on temperature from 10 to 50 °C. These results are not actually as good as those reported in the literature, but this preliminary work proposes simpler and cheaper processes to realize NH3 sensor for room temperature applications.

A series of Europium (Eu) and Strontium (Sr) codoped hydroxyapatite samples (Ca10-x-Srx-HAp: Eu) were designed and prepared using the chemical co-precipitation method. The crystalline structure, chemical composition and luminescent property of samples were characterized by X-ray diffraction (XRD) and photoluminescent spectrum (PL). XRD patterns showed that Eu doping had little effect on the structure of the samples, while with the increase of Sr content, crystallinity and interplanar crystal spacing were increased. PL spectra indicate that the fluorescence intensity at 596 nm and 618 nm of Ca-Sr-HAp: Eu samples increased firstly and then decreased with increase of Sr content at 394 nm excitation, and the strongest peak appeared in the Ca3-Sr7-HAp: Eu samples. At the same time, the fluorescence lifetime of the samples showed the same tendency with the increase of Sr content. In addition, the ratio of magnitude between electric dipole and magnetic dipole transition (IR/IO) also increased firstly and decreased subsequently along with the increase of Sr content in the matrix. Furthermore, the energy transfer 1104 无 机 材 料 学 报 第 31卷 parameters (f) calculated from luminescent dynamic of Eu correlating to different sites and transitions present the reverse change. It is concluded that the doped sites of Eu ions in the host lattice are affected by the content and location of Sr ions in the matrix. Thereby a tunable luminescent property of Ca10-x-Srx-HAp: Eu samples can be obtained by changing the site of Eu ions in the matrix through adjusting the value of Sr/Ca.

The objective of this study was to investigate the spectral behavior of the relationship between reflectance and chlorophyll content and to develop a technique for non-destructive chlorophyll estimation and distribution in leaves using hyperspectral imaging. The hyperspectral imaging data cube of cucumber (Cucumis sativus) leaves in the range of 450-850 nm was investigated and preprocessed. Sixty optical signatures or indices as a function of the associated reflectance (R(λ)) at the special wavelength (λ) nm which proposed in the literatures were used to predict the total chlorophyll content in cucumber leaves. Finally, R(710)/R(760), (R(780)-R(710))/(R(780)-R(680)), (R(750)-R(705))/(R(750)+R(705)), (R(680)-R(430))/(R(680)+R(430)), R(860)/(R(550)×R(708)), (R(695-705))(-1)-(R(750-800))(-1), and REP-LEM (a index based on red edge position and estimated with a linear extrapolation method) were identified as optimum indices. Red-edge waveband (680-780 nm) appeared in all these optimum indices, indicating the importance of REP (red edge position) in chlorophyll estimation. When (R(695-705))(-1)-(R(750-800))(-1), the best index was applied to an independent validation set, chlorophyll content (r=0.8286) were reasonably well predicted, indicating model robustness. Depending on the sample, this technique enables to identify and characterize the relative content of various chlorophyll that distribution in the cucumber leaves. The map shows a relatively low level of chlorophyll at margins. Higher level can be noticed in the regions along the main veins and in some areas exhibiting dark green tissue. Our results indicate that hyperspectral imaging has considerable promise for predicting pigments in leaves and, the pigments can be detected in situ in living plant samples non-destructively.

More than 3.2 million litres of vinegar is consumed every day in China. There are many types of vinegar in China. How to control the quality of vinegar is problem. Near infrared spectroscopy (NIR) transmission technique was applied to achieve this purpose. Ninety-five vinegar samples from 14 origins covering 11 provinces in China were collected. They were classified into mature vinegar, aromatic vinegar, rice vinegar, fruit vinegar, and white vinegar. Fruit vinegar and white vinegar were separated from the other traditional categories in the two-dimension principal component space of NIR after principle component analysis (PCA). Least-squares support vector machine (LS-SVM) as the pattern recognition was firstly applied to identify mature vinegar, aromatic vinegar, rice vinegar in this study. The top two principal components (PCs) were extracted as the input of LS-SVM classifiers by principal component analysis (PCA). The best experimental results were obtained using the radial basis function (RBF) LS-SVM classifier with σ = 0.8. The accuracies of identification were more than 85% for three traditional vinegar categories. Compared with the back propagation artificial neural network (BP-ANN) approach, LS-SVM algorithm showed its excellent generalisation for identification results. As total acid content (TAC) is highly connecting with the quality of vinegar, NIR was used to prediction the TAC of samples. LS-SVM was applied to building the TAC prediction model based on spectral transmission rate. Compared with partial least-square (PLS) model, LS-SVM model gave better precision and accuracy in predicting TAC. The determination coefficient for prediction ( R p ) of the LS-SVM model was 0.919 and root mean square error for prediction (RMSEP) was 0.3226. This work demonstrated that near infrared spectroscopy technique coupled with LS-SVM could be used as a quality control method for vinegar.