Yuchang Qin

Chinese Academy of Agricultural Sciences, Beijing, Beijing Shi, China

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Publications (9)26.69 Total impact

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    ABSTRACT: The objective of the study was to obtain pharmacokinetic parameters for melamine and blend of melamine (MEL) and cyanuric acid (CYA) in rainbow trout (Oncorhynchus mykiss). The single target dosage of MEL (20mg/kg bw) and the blend of MEL and CYA (5 and 1.67 mg/kg bw, respectively) were designed and plasma samples were collected at 30 min, 1, 4, 8, 12, 20, 24, 36, 48, 72, 144 and 240 h sequentially. An optimized method for simultaneous determination of MEL and CYA in plasma and animal tissues by LC-MS/MS was used. The data were shown to best fit a non-compartment model with first order processes of linear characters for melamine, with half-life (t(½)) of 32.2-32.9h, clearance (Cl(z/F)) of 35.9-36.6 ml/h/kg, and volume of distribution (V(ss)) of 1.67-1.74 l/kg. Withdrawal of CYA was much more rapid than that of MEL with higher Cl(z/F) (783.56 ml/h/kg) and shorter t(½) (7.92 h). T(max) of MEL20 and MEL5 were 12 and 20 h, respectively, which showed that T(max) of MEL5 was delayed when MEL and CYA were given together. The results are quite different from those in mammals and showed much slower elimination of MEL and CYA from rainbow trout body.
    Regulatory Toxicology and Pharmacology 06/2011; 61(1):93-7. · 2.13 Impact Factor
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    ABSTRACT: Using near-infrared spectroscopy and thermogravimetry coupled with differential scanning calorimetry (TG-DSC), we investigated the characteristics of water in starch and the effects of the inner structure of starch on dehydration. The results directly show that the dehydration process is significantly more favorable in native starch than in gelatinized starch. When the starch was heated to 100 °C, the water retention in gelatinized starch was 22.35 per total water content, much greater than that in native starch (4.3%). The hydrogen bond network that changes from native starch to gelatinized starch was simultaneously explored, and the weaker hydrogen bonds were found to be predominant in the hydrogen bond network of gelatinized starch.
    Journal of Agricultural and Food Chemistry 01/2011; 59(1):256-62. · 2.91 Impact Factor
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    ABSTRACT: To investigate the deposition and elimination of melamine in hen eggs and tissues, 72 Roman laying hens were administrated with melamine at 8.6-140.9 mg per kilogram of body weight per day for 34 days. The crystals were found in one of three kidneys of hens treated with melamine at either 62.6 or 140.9 mg/kg. Furthermore, the melamine concentrations in egg, muscle, liver, kidney, stomach, duodenum, uterus, ovary, and blood plasma were determined by high-performance liquid chromatography-ultraviolet (HPLC-UV) methods. A higher dosage of melamine in the diet corresponded to higher concentrations in tissues and eggs. The concentrations of melamine in tissues were in the following ranges (microg/g): egg, 1.1-28.7; muscle, 0.4-9.3; liver, 0.5-6.9; kidney, 1.3-21.7; stomach, 0.4-7.3; duodenum, 0.3-2.8; uterus, 0.5-6.9; ovary, 0.5-9.1; and blood plasma, 0.8-7.6. When melamine was withdrawn from the diet of hens, the melamine concentration in hen tissues fell to below 2.5 microg/g by day 10 and no residues were detected in eggs or tissues at days 7 and 20, respectively.
    Journal of Agricultural and Food Chemistry 04/2010; 58(9):5414-20. · 2.91 Impact Factor
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    ABSTRACT: The scandal of melamine-adulterated infant formula in China in September 2008 demanded the need to assess the extent of melamine contamination in the environment and food products and possible risks of consuming melamine-contaminated diets. In this work, our extensive work tested water, soil and crop samples from 21 provinces in China. Soils nearby and waste waters from melamine-manufacturing factories were examined, and the highest melamine concentrations in waste water and soil samples were 226.766 and 41.136 mg/kg, respectively. Six of 94 irrigation water samples had melamine at a concentration of 21-198 microg/L. Only 1 sample collected from 124 farmlands farther than 150 km from melamine factories was detected for melamine at a content of 176 microg/L. Only 3 out of 557 crop samples contaminated more than 1mg/kg melamine, with the highest level of 2.05 mg/kg in a wheat sample. When basal diets contained 2mg/kg melamine were fed to various animals, deposition of melamine in animal tissues and products was all lower than 122 microg/kg. The melamine deposition was much higher (e.g., 4483 microg/kg in the kidney of chicken) when diets contained 100 mg/kg melamine but was found to be completely depleted after 96 h for all animals after switching to the basal diets. Our work may be valuable to regulate melamine production and monitor the safety of food and animal products.
    Environment international 04/2010; 36(5):446-52. · 4.79 Impact Factor
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    ABSTRACT: Many countries have introduced maximum residue limits for melamine in foods since its adulteration in infant formula in China. However, more animal feeding studies are needed to understand the fate of melamine-contaminated animal feed. In this study, the melamine contents in tissues and serum were tested using LC-MS/MS for up to 60 days for lambs fed with diets containing 2-100 mg of melamine per kg of diet. A higher dose of melamine in the diet resulted in a higher concentration in tissues and serum, with the maximum melamine content in the kidney. When cyanuric acid was coadministered at an equal concentration to that of melamine, the deposition of melamine in lambs was similar to the treatment with melamine only and was much higher than the deposition of cyanuric acid. When melamine was withdrawn from the diet, melamine concentrations decreased below 20 microg/kg in all tissues after 4 days. The present study may provide available information for future work about the risk assessment of melamine to human health.
    Journal of Agricultural and Food Chemistry 01/2010; 58(2):943-8. · 2.91 Impact Factor
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    ABSTRACT: The degradation of intracytosolic proteins has been well described. However, the degradation pathway and physiological functions of the DNA-Bound peptides, which are free of degradation by peptidase of the post-ubiquitin-proteasome pathway, are still unclear. In this study, the DNA-Bound peptides were isolated from barley germ and two main fractions of about 25 different peptides were obtained. The DNA-Bound peptides were found to inhibit the proliferation of HeLa cells in a series of experiments. The DNA-Bound peptides also significantly inhibited in vitro and in vivo DNA transcription activity by regulating the expression and the corresponding functions of CDK7. Furthermore, signaling issues involving NFkappaB and ERK1/2 were observed. Such data suggests that DNA transcription could be inhibited by the DNA-Bound peptides via the CDK7 pathway. Thus we concluded that some of the post-proteasomal peptides were involved in the regulation of eukaryotic mRNA transcription.
    Peptides 12/2008; 30(4):681-8. · 2.52 Impact Factor
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    ABSTRACT: Standard methods for determining the raw material content of compound feed are little exploited, except for the identification of meat and bone meal in feeds. In this work, near-infrared (NIR) spectroscopy and real-time polymerase chain reaction (PCR) were applied in order to establish new and fast methods for quantification of soybean meal content in compound feeds. The best prediction quality was achieved by using a model based on NIR spectroscopy (R2 = 0.9857, standard error of cross-validation 1.1065). Furthermore, a sensitive qualitative detection method by using the real-time PCR was developed (R2 = 0.976, slope -3.7599). Finally, the differences between the real-time PCR result and the NIR spectroscopy result for a given sample were also treated, and we found that the NIR spectroscopy method provided quite accurate results which approach closely those of the real-time PCR method.
    Analytical and Bioanalytical Chemistry 01/2008; 389(7-8):2313-22. · 3.66 Impact Factor
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    ABSTRACT: The application of biotechnological products in the feed industry has undergone explosive growth in recent years, and phytase from microorganism accounts for one-third of the entire feed enzyme market. In this study, some differences in the composition of protein and denaturation temperature between two commercial phytases were determined by HPLC and differential scanning calorimetry, which were derived from the same origin of E. coli. At the same time, we found that it was advantageous for near-infrared reflectance spectroscopy (NIRS) to display the protein differences in the commercial phytase, which is most important for ensuring the traceability of biotechnological products in feed and food safety control. Furthermore, NIRS could track the changes in phytase during the spray-drying process and the change of enzyme activity during storage of phytase. Our experiments proved that the information from NIRS could describe well the individual characteristics of the commercial phytase, which indicated that near-infrared reflectance spectra could be exploited to use in the registration system of commercial phytase.
    Journal of Agricultural and Food Chemistry 10/2007; 55(19):7667-75. · 2.91 Impact Factor
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    ABSTRACT: Analysis of fishmeal concentrations in feedstuff is critical to quality control and ingredient statement of commercial feed. Near-infrared reflectance spectroscopy (NIRS) determination for fishmeal was established through the spectral data processed by mean center, normalization, Savitzky–Golay first, partial least square 1 and cross validation. The coefficient of determination (R 2) of NIRS calibration model, the standard error estimated by cross validation (SECV) were 0.9554 and 0.9541, respectively. At the same time, the coefficient of determination of validation was 0.9867. Moreover, it has been proven to be directly correlated between the fishmeal spectra and the loading of the second principal components, and the coefficient of determination of the spectra of the calibration model. These results support our theory that the NIRS method constructed in our study could be used to quantify fishmeal in compound feeds.
    Food Analytical Methods 6(3). · 1.97 Impact Factor