Search

An HPLC-free radical-scavenging activity detection (HPLC-FRSAD) method was established to evaluate the antioxidant activity of each component in a mixed standard phenolics solution (MSPs). This method quickly displayed the differences in each composition in the MSPs with regard to their scavenging abilities by DPPH radical and ABTS radical cation. The relationship between the structures and the antioxidant activities of the compounds was discussed. Gallic acid, quercetin, and kaempferol in the MSPs’ compositions represented stronger scavenging activities of DPPH radical and ABTS radical cation. Furthermore, the developed method was successfully applied to screen major antioxidants from guava leaf tea extract (GLTE). The results revealed that the gallic acid, procyanidin B3, quercetin, and kaempferol in the extract had higher DPPH radical and ABTS radical cation scavenging activities than other components, which would be responsible for the antioxidant activities of GLTE. The present method provides a useful strategy for rapidly recognizing the key antioxidant components in complex natural products.

Plant polysaccharides possess multiple physiological activities. Box-Behnken design (BBD) was employed to optimize the ultrasound-assisted extraction of polysaccharides from guava leaves (GLP). It was found that ultrasonic time, temperature and power has a significant effect on the extraction efficiency. The yield of GLP was 1.00 ± 0.04% under the optimal condition of extraction time of 20 min, temperature of 62 ℃ and ultrasound power of 404 W. The DPPH and ABTS+ radical scavenging rate of GLP was 56.38% and 51.73% at 100 μg/mL, respectively. The rate of inhibition of α-amylase by GLP was only 14.06% at 1 mg/mL; however, its α-glucosidase inhibition rate reached 99.54% at 100 μg/mL. These results suggested that the ultrasound-assisted extraction for GLP is effective and environmentally friendly and GLP has wide application potentials as natural antioxidants and α-glucosidase inhibitors.

At the end of 2015, the Chinese government enacted the “supply-side structural reform”. The fundamental purpose of this reform is to implement people-centered development and to improve the level of social productivity. As different types of farmers have different needs in terms of management incentives, it is necessary to evaluate the attitudes of Chinese farmers in the period of agricultural supply-side structural reform. In this study we used the Q-methodology to divide 26 grain-planting farmers in the Huaihe Basin into three types, positive development farmer (PD), negative development farmer (ND) and family support farmer (FS), based on their attitudes towards policy, land, livelihood and planting plan. We found that: (1) Policy: FS-type evaluated the direct subsidy policy most highly. In contrast, ND-type had the most negative attitudes toward food-related policies. (2) Land: PD-type, which are representative of the new generation of grain farmers, had the highest dependence on the land, and land resources are likely to become their most scarce resource. (3) Livelihood: ND-type had the highest responsiveness to livelihoods, and they were most inclined to co-op. (4) Planting plan: FS-type were the most likely to replace food crops with cash crops. PD-type’s planting plan is limited by the sales capacity, and ND-type’s planting plan is most affected by technology. According to the characteristics of Chinese farmers, expanding the classification of different aspects is not only the development of the Q classification in the study of farmers, but also a new perspective to study the individual differences of Chinese farmers under the background of supply-side structural reform.

Visfatin plays an important role in regulation of inflammatory cytokines. However, the role of visfatin under bacterial stress condition is not fully explored yet. Therefore, the present study was conducted for the better understanding of the regulation mechanism of visfatin on the production of inflammatory cytokines under lipopolysaccharide (LPS) stress in RAW264.7 murine macrophages. Enzyme Linked Immuno-sorbent Assay (ELISA) results showed that, as compared to the control group, visfatin significantly up-regulated the levels of interleukin (IL)-1β, IL-6, IL-10, tumor necrosis factor (TNF)-α (P 0.05). Compared to the LPS group, the levels of IL-1β, IL-10, TNF-α was down-regulated in visfatin + LPS group (P0.05). After adding p38 inhibitor, SB203580 to culture, the production of IL-1β, IL-6, IL-10, TNF-α was significantly reduced as compared to visfatin only (P 0.01). The results showed that visfatin may regulate the production of IL-1β, IL-6, IL-10, TNF-α through the p38 signaling pathway. As compared to the PBS group, phosphorylayed p38 (P-p38) level in visfatin group was significantly decreased (P 0.05). Compared with LPS group, P-p38 level was significantly decreased in visfatin + LPS group (P 0.05). Hence, it is concluded that visfatin can significantly increase the levels of IL-1β, IL-10 and TNF-α in normal conditions, while their levels significantly decrease during inflammation. Moreover, visfatin participates in the inflammatory response through the p38 mitogen-activated protein kinase (MAPK) signal pathway by the up-regulation of p38 and down-regulation of P-p38 levels.

This article illustrated the development of a web simulation system based on Matlab distributed parallel cluster. The web simulation system construct a visual and controllable simulation interface using javascript and Asynchronous JavaScript and XML(AJAX) technology. In order to realize the Matlab resources dynamic allocation and management, elastic resources management method has been adopted. To achieve the multi-user concurrent access, the resource management system has been designed by adopting principle of feedback control and principle of Apache Hadoop Yet Another Resource Negotiator(YARN). The feasibility of this system demonstrated through application of simulation and practical use.

This study aims to address the fundamental mechanical behavior of soft clay stabilized by the composite of citric-acid-modified magnesium oxysulfate cement, silica fume, and clinker (CMMOSC-S-C composite) at different initial soil-water contents (w), amounts of stabilizing agent (Wg), and curing time (T). X-ray diffraction analysis and Scanning electron microscopy indicate that the main products of the curing reaction can be summarized as 5·1·7 phase, gel, dolomite, pyrophyllite, and minor amounts of CaO and MgO, which could be attributed to the hydration, carbonation, ion exchange, and filling. The unconfined compressive strength tests, one-dimensional consolidation tests and unconsolidated undrained triaxial compression tests show that the unconfined compressive strengths (qu), secant Young's modulus (E50), and shear strength parameters (c and φ) are positively dependent on Wg and T. However, these parameters demonstrate a negative relationship with w. The compression efficient (a2–4) is positively and negatively related to w, Wg, and T. In view of these test results, empirical relationships between the fundamental mechanical parameters of CMMOSC-S-C composite stabilized soft clay and key effect factors (w, Wg, T) are developed to predict the qu, E50, a2–4, c, and φ values at any w, Wg, and T.

According to the magneto-optic (MO) perturbation theory, the coupled-mode equations for guided optical waves (GOWs) with microwave magneto-static waves (MSWs) in MO film waveguides are presented, which cannot only be used to analyze the MO modulation induced by MSW pulses, but also explain the optical pulse compression caused by chirped MSWs. The rectangular pulse modulation of continuous guided optical waves by magnetostatic forward volume waves (MSFVWs) excited under normal bias magnetic field is theoretically studied in detail. It is shown that: (1) the diffracted light pulse approximates to an isosceles trapezoid, which is in agreement with the experimental results, and the duration time and the flat-top response time are equal to the sum and difference between the width and transit time of the rectangular MSFVW pulse, respectively; (2) utilizing a small duty factor of MSFVW pulse helps to improve the modulating data rate, which is in inverse proportion to the transit time, and the relative peak intensity of the diffracted light pulse is less than the corresponding Bragg diffraction efficiency when the MSW duty factor is less than 0.5.