A novel application of entropy analysis for assessing changes in movement variability during cumulative tackles in young elite rugby league players

The aim of this study was to identify between-position (forwards vs. backs) differences in movement variability in cumulative tackle events training during both attacking and defensive roles. Eleven elite adolescent male rugby league players volunteered to participate in this study (mean ± SD, age; 18.5 ± 0.5 years, height; 179.5 ± 5.0 cm, body mass; 88.3 ± 13.0 kg). Participants performed a drill encompassing four blocks of six tackling (i.e. tackling an opponent) and six tackled (i.e. being tackled by an opponent while carrying a ball) events (i.e. 48 total tackles) while wearing a micro-technological inertial measurement unit (WIMU, Realtrack Systems, Spain). The acceleration data were used to calculate sample entropy (SampEn) to analyse the movement variability during tackles performance. In tackling actions SampEn showed significant between-position differences in block 1 (p = 0.0001) and block 2 (p = 0.0003). Significant between-block differences were observed in backs (block 1 vs 3, p = 0,0021; and block 1 vs 4, p = 0,0001) but not in forwards. When being tackled, SampEn showed significant between-position differences in block 1 (p = 0.0007) and block 3 (p = 0.0118). Significant between-block differences were only observed for backs in block 1 vs 4 (p = 0,0025). Movement variability shows a progressive reduction with cumulative tackle events, especially in backs and when in the defensive role (tackling). Forwards present lower movement variability values in all blocks, particularly in the first block, both in the attacking and defensive role. Entropy measures can be used by practitioners as an alternative tool to analyse the temporal structure of variability of tackle actions and quantify the load of these actions according to playing position.     

Comprehensive evaluation of multiple cropping systems on upland red soil

According to the principles and methods of ecology and system engineering,we set up an evaluation indicator system for multi-component and multiple crop-ping systems,evaluated the comprehensive benefits of multi-component and multiple cropping systems using grey relation clustering analysis and screened out the opti-mized model based on research done in the upland red soil in Jiangxi Agricultural University from 1984 to 2004.The results show that the grey relation degree of "cabbage/ potato/maize-sesame" was the highest among 23 multi-component and multiple cropping systems and was clustered into the optimized system.This indicates that "cabbage/potato/maize - sesame" can bring the best social,economic and ecological benefits,increase product yield and farmers' income and promote sustainable development of agricultural production.Therefore,it is suitable for promotion on upland red soil.The grey rela-tion degree of "canola/Chinese milk vetch/maize/mung bean/maize" was second,which is suitable for imple-mentation at the city outskirts.In conclusion,these two planting patterns are expected to play important roles in the reconstruction of the planting structure and optimiza-tion of the planting patterns on upland red soil.     

Monitoring in a predator–prey systems via a class of high order observer design

The goal of this work is the monitoring of the corresponding species in a class of predator–prey systems, this issue is important from the ecology point of view to analyze the population dynamics. The above is done via a nonlinear observer design which contains on its structure a high order polynomial form of the estimation error. A theoretical frame is provided in order to show the convergence characteristics of the proposed observer, where it can be concluded that the performance of the observer is improved as the order of the polynomial is high. The proposed methodology is applied to a class of Lotka–Volterra systems with two and three species. Finally, numerical simulations present the performance of the proposed observer.     

Why ribonucleases induce tumor cell death

The characteristics and the possible mechanisms of action of cytotoxic ribonucleases (RNases), promising antitumor drugs, are described. Original experimental data and the results of analysis of recent publications have made it possible to identify the cellular components providing for the selective effects of exogenous RNases on tumor cells, on the one hand, and to estimate the contributions of individual molecular determinants to the enzyme cytotoxicity, on the other hand. The predominant effect of the electric charge of the RNase molecule on the induction of cell death has been demonstrated. The cytotoxic effects of RNases are determined by the catalytic cleavage of accessible RNA, the action of the products of its hydrolysis, and the noncatalytic electrostatic interaction of the exogenous enzyme with cell components. Potential RNase targets in a tumor cell and the role of modulation of calcium-dependent potassium channels and the ras oncogene in RNase-induced cell damage are considered. The effect of cytotoxic RNases on gene expression by affecting RNA interference is discussed.Translated from Molekulyarnaya Biologiya, Vol. 39, No. 1, 2005, pp. 3–13.Original Russian Text Copyright © 2005 by Ilinskaya, Makarov.     

Stochastic P systems and the simulation of biochemical processes with dynamic compartments

We introduce a sequential rewriting strategy for P systems based on Gillespie's stochastic simulation algorithm, and show that the resulting formalism of stochastic P systems makes it possible to simulate biochemical processes in dynamically changing, nested compartments. Stochastic P systems have been implemented using the spatially explicit programming language MGS. Implementation examples include models of the Lotka-Volterra auto-catalytic system, and the life cycle of the Semliki Forest virus.     

p53-Knockout Mice Are Protected Against the Long-Term Effects of Methamphetamine on Dopaminergic Terminals and Cell Bodies

Abstract: p53-knockout mice provide a useful model to test the role of p53 in the neurotoxic effects of drugs in vivo. To test the involvement of p53 in methamphetamine (METH)-induced toxicity, wild-type mice, as well as heterozygous and homozygous p53-knockout male mice, were administered four injections of three different doses (2.5, 5.0, and 10.0 mg/kg) of the drug given at 2-h intervals within the space of 1 day. METH caused a marked dose-dependent loss of dopamine transporters in both the striatum and the nucleus accumbens of wild-type mice killed 2 weeks after drug administration. However, this METH-induced decrease in dopamine transporters was attenuated in both homozygous and heterozygous p53-knockout mice, with homozygous animals showing significantly greater protection. The possibility for p53 involvement in METH-induced toxicity was also supported by the observation that METH caused marked increases in p53-like immunoreactivity in the striata of wild-type mice and very little change in heterozygous p53-knockout mice, whereas no p53-like immunostaining was detected in the homozygous p53-knockout mice. Further support for p53 involvement was provided by the fact that METH treatment caused significant decreases in dopamine transporter mRNA and the number of tyrosine hydroxylase-positive cells in the substantia nigra pars compacta and the ventral tegmental area of wild-type but not homozygous p53-knockout mice killed 2 weeks after cessation of METH administration. These results provide concordant evidence for a role of the tumor suppressor, p53, in the long-term deleterious effects of a drug acting on brain dopamine systems.     

具空间扩散的时变种群系统的最优捕获控制

讨论了一类时变种群扩散系统的最优捕获控制的非线性问题,证明了最优捕获控制的存在性,并给出了控制u（t,x）∈Uad为最优的必要条件和最优性组．     

Nucleotide Binding Domain Interactions During the Mechanochemical Reaction Cycle of ATP-Binding Cassette Transporters

ATP-binding cassette (ABC) transporters serve as importers and exporters for a wide variety of solutes in both prokaryotes and eukaryotes, and are implicated in microbial drug resistance and a number of significant human genetic disorders. Initial crystal structures of the soluble nucleotide binding domains (NBDs) of ABC transporters, while a significant step towards understanding the coupling of ATP binding and hydrolysis to transport, presented researchers with important questions surrounding the role of the signature sequence residues, the composition of the nucleotide binding sites, and the mode of NBD dimerization during the transport reaction cycle. Recent studies have begun to address these concerns. This mini-review summarizes the biochemical and structural characterizations of two archaebacterial NBDs from Methanocaldococcus jannaschii, MJ0796 and MJ1267, and offers current perspectives on the functional mechanism of ABC transporters.