Studies on antioxidant capacity of anthocyanin extract from purple sweet potato (Ipomoea batatas L.)

The radical scavenging effects by α,α-diphenyl-β-picrylhydrazyl (DPPH) and superoxide anions of anthocyanin extract from purple sweet potato were investigated. The antioxidation experiments showed that the reducing power of the anthocyanin extract reduced 0.572 at 0.5 mg/ml, while those of Lascorbic acid (L-AA) and butylated hydroxytoluene (BHT) reduced 0.460 and 0.121, respectively. They also displayed potent antioxidant effects against the DPPH radical and superoxide anions radical, showing the IC50 values of 6.94 and 3.68 μg/ml, respectively. Moreover, this anthocyanin extract also could significantly inhibit the formation of lipid peroxidation compound. Sixteen kinds of anthocyanins in purple sweet potato were detected by high-performance liquid chromatography with diode-array detection (HPLC-DAD), and most of the anthocyanins were acylated.Key words: Antioxidant activity, anthocyanins, purple sweet potato

Structure Properties of Generalized Farey graphs based on Dynamical Systems for Networks

Farey graphs are simultaneously small-world, uniquely Hamiltonian, minimally 3-colorable, maximally outerplanar and perfect. Farey graphs are therefore famous in deterministic models for complex networks. By lacking of the most important characteristics of scale-free, Farey graphs are not a good model for networks associated with some empirical complex systems. We discuss here a category of graphs which are extension of the well-known Farey graphs. These new models are named generalized Farey graphs here. We focus on the analysis of the topological characteristics of the new models and deduce the complicated and graceful analytical results from the growth mechanism used in generalized Farey graphs. The conclusions show that the new models not only possess the properties of being small-world and highly clustered, but also possess the quality of being scale-free. We also find that it is precisely because of the exponential increase of nodes’ degrees in generalized Farey graphs as they grow that caused the new networks to have scale-free characteristics. In contrast, the linear incrementation of nodes’ degrees in Farey graphs can only cause an exponential degree distribution

Identification of the relationship between Chinese Adiantum reniforme var. sinense and Canary Adiantum reniforme

© 2014 Wang et al.; licensee BioMed Central. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated

On the error term in Weyl's law for the Heisenberg manifolds (II)

In this paper we study the mean square of the error term in the Weyl's law of an irrational $(2l+1)$-dimensional Heisenberg manifold . An asymptotic formula is established

Processing and properties of bulk Y-Ba-Cu-O superconductors fabricated by top seeded melt growth from precursor pellets containing a graded CeO<inf>2</inf> composition

The existence of a zone containing a low concentration of Y2BaCuO5 (Y-211) phase particles in the vicinity of the seed in single grain, bulk Y–Ba–Cu–O (YBCO) superconductors fabricated by the top seeded melt growth (TSMG) technique has been reported, suggesting the presence of low intrinsic magnetic flux pinning, and hence reduced trapped field, in this region of the sample. The possibility of introducing additional pinning centers in the vicinity of the seed in single grain YBCO, therefore, may be effective in improving the applied magnetic properties of these technologically important materials. Single grain, bulk YBCO superconductors fabricated from precursor pellets containing a graded CeO2 composition have been prepared corresponding to a secondary phase content of 2 wt % CeO2 beneath the seed and 1 wt % CeO2 at the outer, “U” shape cross-section, of the sample. The resulting graded single grain YBCO superconductors exhibit enhanced trapped field compared to standard YBCO superconductors fabricated by TSMG from precursor pellets containing purely 1 wt % CeO2. The influence of CeO2 content on the microstructure, growth process, and superconducting properties of bulk, single grain YBCO superconductors fabricated by TSMG has been investigated and used to explain the increased trapped field ability of the graded composition.This work was supported by the Engineering and Physical Sciences Research Council, EPSRC, [Grant Number EP/ K02910X/1]. W.Z. would like to acknowledge financial support from the China Scholarship Council and the Cambridge Commonwealth, European and International Trust.This is the final published version. It first appeared at http://pubs.acs.org/doi/abs/10.1021/cg501724y