Environmental fate and toxicity of androgens: A critical review.

Androgens are released by humans and livestock into the environment and which cause potent endocrine disruptions even at nanogram per liter levels. In this article, we reviewed updated research results on the structure, source, distribution characteristics and the fate of androgens in ecological systems; and emphasized the potential risk of androgens in aquatic organism. Androgens have moderately solubility in water (23.6-58.4 mg/L) and moderately hydrophobic (log Kow 2.75-4.40). The concentration of androgens in surface waters were mostly in ng/L ranges. The removal efficiencies of main wastewater treatment processes were about 70-100%, except oxidation ditch and stabilization ponds. Sludge adsorption and microbial degradation play important role in the androgens remove. The conjugated androgens were transformed into free androgens in environmental matrices. Global efforts to provide more toxicity data and establish standard monitoring methods need a revisit. Of the day available, there is an urgent need for comprehensive consideration of the impact of androgens on the environment and ecology.

DCT Inspired Feature Transform for Image Retrieval and Reconstruction.

Scale invariant feature transform (SIFT) is effective for representing images in computer vision tasks, as one of the most resistant feature descriptions to common image deformations. However, two issues should be addressed: first, feature description based on gradient accumulation is not compact and contains redundancies; second, multiple orientations are often extracted from one local region and therefore produce multiple descriptions, which is not good for memory efficiency. To resolve these two issues, this paper introduces a novel method to determine the dominant orientation for multiple-orientation cases, named discrete cosine transform (DCT) intrinsic orientation, and a new DCT inspired feature transform (DIFT). In each local region, it first computes a unique DCT intrinsic orientation via DCT matrix and rotates the region accordingly, and then describes the rotated region with partial DCT matrix coefficients to produce an optimized low-dimensional descriptor. We test the accuracy and robustness of DIFT on real image matching. Afterward, extensive applications performed on public benchmarks for visual retrieval show that using DCT intrinsic orientation achieves performance on a par with SIFT, but with only 60% of its features; replacing the SIFT description with DIFT reduces dimensions from 128 to 32 and improves precision. Image reconstruction resulting from DIFT is presented to show another of its advantages over SIFT.

Separation and Purification of Prim-O-glucosylcimifugin and 5-O-methylvisammioside from Saposhnikovia Divaricata by High-speed Counter-current Chromatography / 分析化学

High-speed counter-current chromatographic ( HSCCC ) method was successfully used to separate and purify prim-O-glucosylcimifugin and 5-0-methylvisammioside from Saposhnikovia divaricata(Thicz. ) Schis-chk. ,a traditional Chinese herb,with a solvent system composed of ethyl acetate-n-butanol-water(2:7:9,V/V). The lower phase of the system was used as the mobile phase at the flow rate of 2.0 mL/min,and the upper phase was used as the stationary phase. The separation produced a total 13.9 mg prim-O-glucosylcimifugin and 25.0 mg 5-0-methylvisammioside with the purity of 98. 1% and 99.2% determined by high performance liquid chromatography (HPLC) from 316 mg of crude sample from S. divaricata. The structures of isolated compounds were identified by ESI-MS,~1H NMR and ~(13)C NMR.