PO-255 Optimization of Ultrasonic Extraction of Maca Polysaccharides and Evaluation of its Anti-fatigue Ability

Objective The aim of this study was to establish the optimal extraction conditions of polysaccharides of Maca (Lepidium meyenii Walp) and explore its anti-fatigue ability of exhaustive exercise rats. Methods Response surface methodology, based on Box-Behnken design, was used to optimize of ultrasonic extraction conditions of maca polysaccharides.Three independent variables (ratio of water to raw material, ultrasonic time, ultrasonic temperature) were taken into consideration. Subsequently, 80 male SD rats were randomly divided into 4 groups, negative control group, low dose group (ML, 130mg/Kg.bw/d), middle dose group (MM, 270mg/Kg.bw/d), high dose group (MH, 800mg/Kg.bw/d). After continuous oral gavage for 30 days, 10 rats were randomly selected from each group to measure the liver glycogen, and the remaining 40 were used to determine the exhaustion swimming time, biochemical indicators of exercise capacity in rats. Results 1. The best extracting method the ratio of material to liquid 1:22g/ml, ultrasonic time was 28min, ultrasonic temperature was 59 degrees centigrade, the extraction rate was 17.6754%. 2. Both middle and high doses of maca polysaccharides could significantly improve the swimming time of exhausted rats. 3. The maca polysaccharides group (ML, MM, MH) could effectively inhibit the growth of lactic acid in rats and accelerated the elimination of lactic acid. The effect of high dose MH group was the most obvious(P＜0.05). 4. The content of BUN in swimming rats was reduced by different doses of maca polysaccharides. High dose of maca polysaccharides on reducing the content of MDA was the most significant(P＜0.05). 6. Different doses of maca polysaccharides increased liver glycogen storage in rats, the high dose of maca polysaccharides to improve the effect of liver glycogen content of rats was the most significantly(P＜0.05). Conclusions 1. The optimum extraction conditions of maca polysaccharides was as follows: the ratio of material to liquid was 1:22g/ml, the ultrasonic time was 30min, the ultrasonic temperature was 60, and the extraction rate was 17.6754%. 2. Maca polysaccharides could improve the antioxidant capacity of the body, improve energy reserves; prolonged exhaustive swimming time. &nbsp

STUDY ON THE INHIBITORY EFFECT OF DRYNARIA FORTUNEI EXTRACT ON HUMAN MYELOMA SP20 CELLS

The objective of the study was to investigate the inhibitory effect of Drynaria fortunei extract on human myeloma SP2 cells. Three different total extracts of Drynaria fortunei were obtained by reflux extraction method using different organic solvents including ethanol, methanol and petroleum ether. Their anticancer activities on SP20 cells were tested, and the maximum inhibition rate was obtained. The inhibitory effects on tumour cells at 12 h, 24 h, 36 h and 48 h were tested, and the inhibition curves at different time periods were plotted. The results showed that the methanol and ethanol extracts have similar inhibition rates at 24 h, which are around 55%. On the other hand, the maximum inhibition rate of petroleum ether extract is only 36% within 24h. Moreover, within the time periods of 36 h and 48 h, its inhibition rates are all below 10%

On Constructions of a Sort of MDS Block Diffusion Matrices for Block Ciphers and Hash Functions

Many modern block ciphers use maximum distance separate (MDS) matrices as their diffusion layers. In this paper, we propose a new method to verify a sort of MDS diffusion block matrices whose blocks are all polynomials in a certain primitive block over the finite field $\mathbb F_2$. And then we discover a new kind of transformations that can retain MDS property of diffusion matrices and generate a series of new MDS matrices from a given one. Moreover, we get an equivalence relation from this kind of transformation. And MDS property is an invariant with respect to this equivalence relation which can greatly reduce the amount of computation when we search for MDS matrices. The minimal polynomials of matrices play an important role in our strategy. To avoid being too theoretical, we list a series of MDS diffusion matrices obtained from our method for some specific parameters. Furthermore, we talk about MDS recursive diffusion layers with our method and extend the corresponding work of M. Sajadieh et al. published on FSE 2012 and the work of S. Wu published on SAC 2012

Predicting human microRNA precursors based on an optimized feature subset generated by GA–SVM

AbstractMicroRNAs (miRNAs) are non-coding RNAs that play important roles in post-transcriptional regulation. Identification of miRNAs is crucial to understanding their biological mechanism. Recently, machine-learning approaches have been employed to predict miRNA precursors (pre-miRNAs). However, features used are divergent and consequently induce different performance. Thus, feature selection is critical for pre-miRNA prediction. We generated an optimized feature subset including 13 features using a hybrid of genetic algorithm and support vector machine (GA–SVM). Based on SVM, the classification performance of the optimized feature subset is much higher than that of the two feature sets used in microPred and miPred by five-fold cross-validation. Finally, we constructed the classifier miR-SF to predict the most recently identified human pre-miRNAs in miRBase (version 16). Compared with microPred and miPred, miR-SF achieved much higher classification performance. Accuracies were 93.97%, 86.21% and 64.66% for miR-SF, microPred and miPred, respectively. Thus, miR-SF is effective for identifying pre-miRNAs

Linkage between surface energy balance non‐closure and horizontal asymmetric turbulent transport

A number of studies have reported that the traditional eddy covariance (EC) method generally underestimated vertical turbulent fluxes, leading to an outstanding non-closure problem of the surface energy balance (SEB). Although it is recognized that the enlarged surface energy imbalance frequently coincides with the increasing wind shear, the role of large eddies in affecting the SEB remains unclear. On analyzing data collected by an EC array, considerable horizontal inhomogeneity of kinematic heat flux is observed. The results show that the combined EC method that incorporates the spatial flux contribution increases the kinematic heat flux by 21% relative to the traditional EC method, improving the SEB closure. Additionally, spectral analysis indicates that large eddies with scales ranging from 0.0005 to 0.01 (in the normalized frequency) mainly account for the horizontal inhomogeneity of kinematic heat flux. Under unstable conditions, this process is operating upon large eddies characterized by enlarged asymmetric turbulent flux transport. With enhanced wind shear, the increment of flux contribution associated with sweeps and ejections becomes disproportionate, contributing to the horizontal inhomogeneity of kinematic heat flux, and thus may explain the increased SEB non-closure

An Efficient Data Collection Protocol Based on Multihop Routing and Single-Node Cooperation in Wireless Sensor Networks

Considering the constrained resource and energy in wireless sensor networks, an efficient data collection protocol named ESCDD which adopts the multihop routing technology and the single-node selection cooperative communication is proposed to make the communication protocol more simple and easy to realize for the large-scale multihop wireless sensor networks. ESCDD uses the greedy strategy and the control information based on RTS/CTS to select forwarding nodes. Then, the hops in the multihop data transmission are reduced. Based on the power control in physical layer and the control frame called CoTS in MAC layer, ESCDD chooses a single cooperative node to perform cooperative transmission. The receiving node adopts maximal ratio combining (MRC) to recover original data. The energy consumption per hop is reduced. Furthermore, the total energy consumption in data collection process is shared by more nodes and the network lifetime is extended. Compared with GeRaF, EERNFS, and REEFG protocol, the simulation results show that ESCDD can effectively reduce the average delay of multihop data transmission, improve the successful delivery rate of data packets, significantly save the energy consumption of network nodes, and make the energy consumption more balanced

Biogeographic Patterns and Assembly Mechanisms of Bacterial Communities Differ Between Habitat Generalists and Specialists Across Elevational Gradients

A core issue in microbial ecology is the need to elucidate the ecological processes and underlying mechanisms involved in microbial community assembly. However, the extent to which these mechanisms differ in importance based on traits of taxa with different niche breadth is poorly understood. Here, we used high-throughput sequencing to examine the relative importance of environmental selection and stochastic processes in shaping soil bacterial sub-communities with different niche breadth (including habitat generalists, specialists and other taxa) across elevational gradients on the subalpine slope of Mount Wutai, Northern China. Our findings suggested that the composition of soil bacterial communities differed significantly different among elevational gradients. According to the niche breadth index, 10.9% of OTUs were defined as habitat generalists (B-value >8.7) and 10.0% of OTUs were defined as habitat specialists (B-value <1.5). Generalists and specialists differed distinctly in diversity and biogeographic patterns across elevational gradients. Environmental selection (deterministic processes) and spatial factors (stochastic processes) seemed to determine the assembly and biogeography of habitat generalists. However, for specialists, deterministic processes strongly influenced the distribution, while stochastic processes were not at play. Environmental drivers for generalists and specialists differed, as did their importance. Elevation, total nitrogen and pH were the main factors determining habitat generalists, and soil water content, nitrate nitrogen and pH had the strongest impacts on specialists. Moreover, variation partitioning analysis revealed that environmental selection had a much greater impact on both generalists (17.7% of pure variance was explained) and specialists (3.6%) than spatial factors. However, generalists had a much stronger response to spatial factors (2.3%) than specialists (0.3%). More importantly, null models of β-diversity suggested that specialists deviated significantly from non-neutral assembly mechanisms (relative null deviation= 0.64–0.74) relative to generalists (0.16–0.65) (P < 0.05). These results indicate that generalists and specialists are governed by different assembly mechanisms and present distinct biogeographical patterns. The large proportion of unexplained variation in specialists (93.3%) implies that very complex assembly mechanisms exist in the assembly of specialists across elevational gradients on the subalpine slope of Mount Wutai. It is essential to understand the microbial community assembly at a more refined level, and to expand the current understanding of microbial ecological mechanisms