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Stratiform chromite deposits in China have long been considered to form by fractional crystallization of mafic magma. However, some researchers recently proposed that some chromite deposits are also hosted in ophiolite. In this study, Cr-spinels of the dunites, wehrlites and clinopyroxenites from the Fangmayu chromite deposit in Beijing are analyzed by EPMA. Results show that Cr-spinels of dunites and wehrlites at the early stage of magma differentiation are rich in Cr with an average Cr2O3 content of 43.32%. At the late stage of magma differentiation, the crystallization of clinopyroxenites consumed large amounts of Cr3+ and elevated the oxygen fugacity, leading to the Cr-rich magnetite and Al-rich spinel with average Cr2O3 contents of 10.32% and 15.77%, respectively. By comparing with the chemical composition of different types of Cr-spinels from the world, the suggestion is that Fangmayu chromite deposit was a magmatic deposit hosted in Alaskan-type intrusion, and was not related to ophiolite. The constraints on the genesis and metallogenic specialization provide evidence for mineral prospecting of Cr, Cu-Ni and PGE deposits hosted in mafic-ultramafic intrusions.

A rapid and sensitive flow-injection chemiluminescence (CL) method for the determination of glipizide was developed on the basis of finding that glipizide can enhance the CL intensity of the luminolâK3Fe(CN)6 system. In optimum condition, the increased CL intensity was directly proportional to the concentration of glipizide in the range from 4.0Ã10â8Â g/mL to 1.0Ã10â6Â g/mL and the detection limit was 1.0Ã10â8Â g/mL glipizide. The relative standard deviation (RSD) of the developed method was 2.1% with 11 repeated measurements of 1.0Ã10â7Â g/mL glipizide. The developed method has been successfully applied to the analysis of glipizide in its pharmaceutical preparations. Keywords: LuminolâK3Fe(CN)6, Glipizide, Flow injection, Chemiluminescence

Amyloid-β (Aβ), the major component of neuritic plaques in Alzheimer's disease (AD), is derived from sequential proteolytic cleavage of amyloid protein precursor (APP) by secretases. In this study, we found that cystatin C (CysC), a natural cysteine protease inhibitor, is able to reduce Aβ40 secretion in human brain microvascular endothelial cells (HBMEC). The CysC-induced Aβ40 reduction was caused by degradation of β-secretase BACE1 through the ubiquitin/proteasome pathway. In contrast, we found that CysC promoted secretion of soluble APPα indicating the activated non-amyloidogenic processing of APP in HBMEC. Further results revealed that α-secretase ADAM10, which was transcriptionally upregulated in response to CysC, was required for the CysC-induced sAPPα secretion. Knockdown of SIRT1 abolished CysC-triggered ADAM10 upregulation and sAPPα production. Taken together, our results demonstrated that exogenously applied CysC can direct amyloidogenic APP processing to non-amyloidgenic pathway in brain endothelial cells, mediated by proteasomal degradation of BACE1 and SIRT1-mediated ADAM10 upregulation. Our study unveils previously unrecognized protective role of CysC in APP processing.