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Yao C.Y.,Nanjing University | Yao C.Y.,Nanjing Center | Ma D.S.,Nanjing University | Ding H.F.,CAS Institute of Remote Sensing | And 2 more authors.
Science China Earth Sciences | Year: 2014

A chert-phosphorite unit from the Sugetbrak section in the Tarim Basin was analyzed for rare earth elements (Ce, Eu), redox sensitive proxies, and carbon isotopic compositions (δ13Ccarb and δ 13Corg) in the lower Yurtus Formation of the Early Cambrian period. Redox sensitive element ratios (Th/U, V/Cr, Ni/Co, and V/Sc) were employed to determine the palaeoenvironmental conditions during this period. The ratios indicated that the depositional environment of the chert-phosphorite-black shale unit ranged from suboxic to anoxic. Negative Ce and positive Eu anomalies in the chert-phosphorite assemblages of the studied Yurtus Formation indicated the existence of a redox-stratified ocean, similar to that of South China. Overturn or upward expansion of the deep water-mass probably reached the shallow marine zone after the formation of the Yurtus phosphorites. The characteristics of the negative Ce anomaly may be due to phosphoritic inheritance from the Ce-depleted signature of the overlying water column. Subsequent hydrothermal inputs and reduced detrital supplies of the deep water caused by the upwelling affected certain redox sensitive elements in the sedimentary basin. δ 13Ccarb and δ13Corg negative excursions in the Yurtus chert-phosphorite unit may be related to a transgression phase when episodic basinal upwelling moved 12C- and P-rich waters from the pelagic basin floor to the continental shelf. Although carbon isotopic compositions in the Yurtus chert-phosphorite assemblages may have suffered from diagenetic alteration, they can be used to probe diagenetic conditions. Multi-proxy geochemical studies indicated that the δ 13Ccarb values of the Yurtus chert-phosphorite assemblages might be considered reflections of a predominantly suboxic environment that was subsequently affected by hydrothermal inputs due to the upwelling. © 2013 Science China Press and Springer-Verlag Berlin Heidelberg. Source

Yao C.,State Key Laboratory for Mineral Deposits Research | Ma D.,State Key Laboratory for Mineral Deposits Research | Ding H.,State Key Laboratory for Mineral Deposits Research | Zhang X.,Jiangsu Environment Monitoring Center
Chinese Journal of Geochemistry | Year: 2011

Carbon isotope chemostratigraphy has been used worldwide for stratigraphic correlation. In this study, δ13Ccarb values are estimated for the Early Cambrian Sugaitebulake section in the Tarim Basin, Xinjiang Autonomous Region, China. As a result, one positive and two negative carbon isotope excursions in the studied section were identified. The δ13Ccarb values reached the maximum negative excursion (N1: -12.39‰) at the basal of the Yuertusi Formation, and then increased to P1. After P1, δ13Ccarb values sharply decreased to about -7.06‰ (N2) in the studied section. The pattern of δ13Ccarb in the Early Cambrian is comparable to the synchronous records of other sections, such as the Laolin section, the Xiaotan section and the Anjiahe section of the Yangtze Platform. It is concluded that the Early Cambrian Yuertusi Formation from the Tarim Basin is within the Nemakit-Daldynian stage, and the lower strata of the Yuertusi Formation may belong to the Zhujiaqing Formation (Meishucun Formation) of the Yangtze Platform. The Ediacaran/Cambrian boundary of the Tarim Block should be located in cherts and phosphorites successions at the basal of the Yuertusi Formation. The δ13Ccarb negative excursion N1 is just across the PC/C boundary, and may be related to certain biomass extinction due to anoxic sedimentary environment, transgression and/or the oceanic overturn. The second δ13Ccarb negative excursion N2 may account for the sea-level falling in the Early Cambrian. © 2011 Science Press, Institute of Geochemistry, CAS and Springer-Verlag Berlin Heidelberg. Source

Yang L.,Nanjing Environment Monitoring Center | Wang M.,Nanjing Environment Monitoring Center | Li J.,Jiangsu Environment Monitoring Center | Hu E.,Nanjing Environment Monitoring Center
Chinese Journal of Chromatography (Se Pu) | Year: 2010

A new method for the determination of tetraethyllead (TEL) in water by gas chromatography-mass spectrometry (GO-MS has been developed. The TEL in water samples (200 mL) was extracted with hexane (50 mL) by adding 20 g NaCl then the extracted solution was concentrated into 1. 0 mL and the internal standard (naphthalene-d8) solution was added to every concentrated solution. The pretreated samples were analyzed by GC-MS. An amount of 1. 0 jxL solution was injected onto an HP-5ms capillary column (30 m xO. 25 mm x 0. 25 μm) and determined by GC-MS in selected ion monitoring (SIM). The selected monitoring ions were m/z 136 236 237, 294 and 295. The m/z 295 was selected as quantitative ion for TEL and m/z 136 for the internal standard. The method had good linearity over the tested concentration range of 0. 02 -0. 40 mg/L (r =0. 999 8 for TEL. The analytical performance characteristics of the proposed procedure were as follows: the detection limit for TEL in 200 mL water sample was 0. 04 μg/L. The average recoveries and the relative standard deviations of TEL were 92. 2% -103% and less than 13. 3% respectively. The method is rapid; convenient and accurate for the determination of water samples. Source

Wang Y.-F.,Nanjing Agricultural University | Shao J.-J.,Nanjing University of Traditional Chinese Medicine | Zhou C.-H.,Jiangsu Environment Monitoring Center | Zhang D.-L.,Nanjing Agricultural University | And 4 more authors.
Food Control | Year: 2012

Curcumin has numerous biological activities but its low stability and water-solubility limit its applications. Microencapsulation of curcumin can improve both of these properties. In this work, food preservation effects of curcumin microcapsules in practical applications for foods such as tofu, bread and cooked pork were studied. The results show that curcumin microcapsules had preservation effects on food when its concentration was above 0.035%, even if it was boiled. Compared with free curcumin, microcapsules not only had better solubility and high heat resistance but also reduced mold spores by (34.4 ± 2.5) to (52.3 ± 4.1)%. Curcumin microcapsules therefore offer a superior choice for preserving food, especially during thermal processing. © 2012 Elsevier Ltd. Source

Wang Y.,Nanjing Agricultural University | Ye H.,Nanjing Agricultural University | Zhou C.,Jiangsu Environment Monitoring Center | Lv F.,Nanjing Agricultural University | And 2 more authors.
European Food Research and Technology | Year: 2012

Spray-drying encapsulation of lutein was conducted to improve its stability and water-solubility. With the porous starch and gelatin as wall material, lutein microcapsules were effectively prepared by spray-drying process. Results showed the optimal technology of lutein encapsulation as follows: the ratio of core to wall material of 1/30, embedding temperature of 60 °C, embedding time 1.5 h, inlet gas temperature of 190 °C, feed flow rate 50 mL/min and drying air flow 60 m 3/h, at which the microcapsules had good encapsulation efficiency (94.4 ± 0.4)% and high yield of product (92.6 ± 1.7)%. Its solubility was increased and it could be directly dissolved in water. The stability of lutein microcapsule in the new carrier mixture against heat, pH, light and oxygen was also greatly improved and their retention rates had been improved about 15-50% than that of free lutein. The results would be helpful to the application of lutein in food industry. © 2011 Springer-Verlag. Source

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