[Commercial orange juice beverages detection by fluorescence spectroscopy combined with PCA-ED and PLSR methods].

In order to classify the orange juiice beverages effectively, the fluorescence character differences of two kinds of orange juice beverages including 100% orange juice and orange drink were analyzed and compared, principal component analysis combined with Euclidean distance was adopted to classify two kinds of orange juice beverages, and ideal classification results were obtained. Meanwhile, the orange juice content estimation model was established by using fluorescence spectroscopy combined with partial least squares regression method, and the correlation coefficient R, root mean square error of calibration RMSEC and root mean square error of prediction RMSEP were 0.997, 0.87% and 2.05%, respectively. The experimental results indicate that the calibration model offers comparatively accurate content estimation, which reflect the actual orange juice content in the commercial orange juice beverages. The exploration to classify orange juice beverages was carried out from two aspects of qualitative and quantitative analysis by employing fluorescence spectroscopy combined with chemometrics method, which can provide a new idea for the classification and adulteration detection of commercial orange juice beverages, and also can give certain reference basis for the quality control of orange juice raw material.

3,3,3',3'-Tetra-methyl-6,6'-bis-[(pyridin-4-yl)meth-oxy]-1,1'-spiro-biindane -monohydrate.

The asymmetric unit in the title compound, C(33)H(34)N(2)O(2)·H(2)O, consists of a V-shaped mol-ecule and a water mol-ecule to which it is hydrogen bonded. The angle between the mean planes of the two spiro-connected indane groups is 77.06 (5)°. The two five-membered rings of the indane groups have envelope conformations with the methyl-ene atoms adjacent to the spiro C atom forming the flaps. They have deviations from the mean plane of the other four atoms in the rings of 0.374 (4) and 0.362 (4) Å. In the crystal, molecules are linked to form inversion dimers via O-H⋯N hydrogen bonds involving the pyridine N atoms and the solvent water mol-ecule. The dimers are linked into a chain along the b axis by π-π stacking inter-actions between a pyridine ring and its centrosymmetrically related ring in an adjacent dimer. The centroid-centroid distance between the planes is 3.7756 (17) Å, the perpendicular distance is 3.4478 (11) Šand the offset is 1.539 Å.

[The study of spectral characteristics of several organophosphate pesticides].

Using Edinburgh FLS920P spectrometer, the authors obtained the UV-visible spectrum and fluorescence spectrum of parathion, metaphos and isocarbophos in their solution of methanol and ethanol respectively, and discussed their spectral characteristics and their mechanisms. Results show that they all have obvious absorption and fluorescence under the excitation of ultraviolet. The absorption peaks of parathion, metaphos and isocarbophos in their methanol and ethanol solution respectively are at 304 nm/298 nm, 304 nm/304 nm and 286 nm/286 nm. The peak wavelengths of fluorescence are at 404 nm/403 nm, 407 nm/ 402 nm and 423 nm/415 nm, fitting fluorescence characteristics of conjugated aromatic compounds that the peak will have red shift with the increasing solvent polarity. The results may contribute to the application of spectral technique in the distinction of pesticides and detection of residues of pesticides in the area of food security supervision.

[Study on saltation of fluorescence excitation spectra of erythrosine].

The fluorescence excitation spectra and absorption spectra of six kinds of erythrosine solutions with concentrations of 10, 20, 30, 40, 50 and 60 microg x mL(-1) were experimentally measured. It was found that the fluorescence excitation peaks are both located at 530 nm significantly when the concentrations of erythrosine solutions are 10 and 20 microg x mL(-1). However, the linetype saltation of fluorescence excitation spectrum occurs as the concentration of erythrosine solution is above 30 microg x mL(-1). The valley is located at 530 nm and two new peaks appear at both flanks of the valley. Compared with fluorescence excitation spectra, the absorption spectra of erythrosine solutions are without saltation and the peaks are all located at 530 nm. According to calculations and a series of contrast experiments, it was demonstrated that the absorption characteristic of erythrosine and the spectral measurement mode conspire to cause the saltation of fluorescence excitation spectra. The results can provide guidance for further research on physical and chemical properties of erythrosine, and offer help and reference for study on saltation behavior in fluorescence excitation spectra and improvement in spectral measuring mode.

[Photophysical properties of novel organic europium (III) complexes].

Based on fluorescence and absorbance spectroscopy, the photophysical properties and mechanisms of novel organic europium (III) complexes in the case of different concentration in ethanol solution and solid flour were studied at room temperature. It was found that the complex absorption spectra are mainly due to the Phenanthroline ligand, gradually exhibit saturated absorption from shortwave to long wave with the concentration increased, and stretch and broaden to long wave. And four characteristic peaks of the fluorescence spectra are all emission spectra of Eu3+ in the complex, and the strongest emission wavelength was 617 nm corresponding to the (5)D0-->(7)F2 transition of Eu2+. And then, it is presented that the perturbation of acetanil ligand changes the parity state of Eu3+ energy field, resulting in the increase of (5)D0-->(7)F2 transition probability, making phenanthroline transfer its energy absorbed to Eu3+, and inducing 617nm strong emission of fluorescence peak.

[Determination and identification of synthetic food colors based on fluorescence spectroscopy and radial basis function neural networks].

Taking ponceau 4R and amaranth as an example, concentration prediction and kind identification of synthetic food colors by fluorescence spectroscopy and radial basis function neural networks are introduced. By using SP-2558 multifunctional spectral measuring system, the fluorescence spectra were measured for solution of ponceau 4R and amaranth excited respectively by the light with the wavelength of 300 and 400 nm. For each sample solution of ponceau 4R, 15 emission wavelength values were selected. The fluorescence intensity corresponding to the selected wavelength was used as the network characteristic parameters, and a radial basis function neural network for concentration prediction was trained and constructed. It was employed to predict ponceau 4R solution concentration of the three kinds of samples, and the relative errors of prediction were 1.42%, 1.44% and 3.93% respectively. In addition, for solution of ponceau 4R and amaranth, the fluorescence intensity corresponding to the fluorescence wavelength was used as the network characteristic parameters, and a radial basis function neural network for kind identification was trained and constructed. It was employed to identify the kind of food colors, and the accuracy is 100%. These results show that the method is convenient, fast, and highly accurate, and can be used for the detection of synthetic food color in food safety supervision and management.

[Quantitative determination of melamine by fluorescence spectroscopy and radial basis function neural networks].

Based on the experimental study, it was found that melamine solution excited by UV light can generate a strong fluorescence. The fluorescence spectrum is within a range from 310 to 600 nm, the peak wavelength of the fluorescence is about 420 nm, and the relationship between fluorescence intensity and melamine solution concentration is nonlinear. A method for the determination of melamine solution concentration was presented, which was based on fluorescence spectroscopy and radial basis function neural networks. For each sample, 30 emission wavelength values were selected, the fluorescence intensity corresponding to the selected wavelength was used as the network data, and a radial basis function neural network was trained and constructed. The trained radial basis function neural network was employed to predict the melamine solution concentration in five kinds of samples, and the relative errors of the results were 0.93%, 0.09%, 0.31%, 1.55% and 4.61%, respectively. The results show that this method can determine the content of melamine quickly and accurately. The whole research outcomes will provide a new method for determining the content of melamine and food safety supervision.

[Fluorescence spectroscopy study of synthetic food colors].

According to the characteristic of synthetic food colors molecule and the relationship between fluorescence and molecular structure, and through analyzing, it has been concluded that synthetic food colors is fluorescent material. By using SP-2558 multifunctional spectral measuring system, the three-dimensional fluorescence spectra of ponceau 4R, amaranth, tartrazine, sunset yellow and brilliant blue were measured. The results show that ponceau 4R excited by light at the wavelength of 330-430 nm can generate a strong fluorescence at the 621 nm peak wavelength with its best excitation wavelength being 376 nm, amaranth excited by light at the wavelength of 300-440 nm can generate a strong fluorescence at the 643 nm peak wavelength with its best excitation wavelength being 370 nm, tartrazine excited by light at the wavelength of 280-380 nm can generate a strong fluorescence at the 565 nm peak wavelength with its best excitation wavelength being 315 nm, sunset yellow excited by light with wavelength of 310-410 nm can generate a strong fluorescence at the 592 nm peak wavelength with its best excitation wavelength being 348 nm, and brilliant blue excited by light at the wavelength of 320-390 nm can generate a strong fluorescence at the 456 nm peak wavelength with its best excitation wavelength being 350 nm. Moreover, the fluorescence spectra of the five kinds of synthetic food colors were discussed. These results can provide helps for testing of food colors and food safety.

[An instantaneous blood pressure measuring system at the wrist based on the volume-compensation method].

An instantaneous blood pressure measuring system at the wrist based on the volume-compensation method is developed, and the characteristics and accuracy of the system is evaluated. The radial artery at the wrist is used as the detecting object, and a pad-type cuff as well as a newly designed electro- pneumatic converter is used in the system. Also, the comparative experiments between the system and the invasive blood measuring device (direct method) indicated that, the results obtained from the two methods are well correlated not only in rest condition, but also in a stressful condition. Therefore, the system is capable of non-invasive measuring instantaneous blood pressure in the radial artery.

[Development of a handy-type monitoring system for cardiovascular haemodynamic functions based on the volume-compensation and electrical admittance method].

A handy-type monitoring system for cardiovascular haemodynamic functions based on the volume-compensation and electrical admittance method is developed. In this system, the inconvenient and discomfort due to cuff occlusion of the biological segment for BP measurement is improved by developing a new device using a local pressurization method, the stability for the physiological information detection is improved by developing a new detecting system, and the noise during detection using the system is greatly reduced by using a newly developed nozzle-flapper type electro-pneumatic converter. Also, for electrical admittance cardiography to estimate CO, the applicability of a two-compartment coaxial cylindrical model and the optimal position of a spot-electrode array that is used to replace the conventional band-electrode are discussed in this research. Experimental result shows that the monitoring system should satisfy non-invasive BP and CO measurement on beat by beat, and the comfort of measurement is significantly improved.

[Expression of aFGF in ovarian epithelial cancer and its signal transduction pathway].

OBJECTIVE: To explore the expression of acidic fibroblast growth factor (aFGF) and its receptor FGFR1 in ovarian epithelial cancer and observe the effects of aFGF and TPK inhibitor Genistein on intracellular PKC and ERK activity in ovarian epithelial cancer cells line CAOV3. METHODS: The expression levels of aFGF and FGFR1 were evaluated by RT-PCR and western blot in 40 cases of ovarian epithelial cancer. The activity of PKC and ERK in cells induced by different concentration of aFGF and Genistein were detected by incorporation of [gamma-(32)P]-ATP into exogenous substrate. RESULTS: The expression levels of aFGFmRNA and FGFR1mRNA in the ovarian epithelial cancer were 0.981 +/- 0.130 and 1.047 +/- 0.148, respectively. Compared with normal ovary, ovarian tumor like condition and benign ovary tumors, the difference was significant (P < 0.05). The expression levels in stage III - IV were significantly higher than those in stage I - II (P < 0.05). There were overexpression of aFGF and FGFR1 in the ovarian epithelial cancer in western blot, too. The intracellular PKC and ERK activity increased with aFGF in a dose dependent manner, Genistein suppressed the intracellular PKC and ERK activity also in a dose dependent manner. CONCLUSION: aFGF may play an important role in carcinogenesis, development and invasion of ovarian epithelial cancer. Its receptor in human ovarian cancer cell line CAOV3 possessed TPK activity. These tyrosine-specific protein phosphorylation may initiate a cascade of biochemical events, which may increase the intracellular PKC and ERK activity. PKC and ERK locate downstream of TPK in CAOV3 cell line.