洗涤用蛋白酶PB92的分子动力学模拟

以蛋白酶PB92结构为基础,分别对无底物结合和有底物结合的蛋白酶PB92进行了分子动力学(MD)模拟来研究其动力学特性,研究得到了有、无底物结合的蛋白酶PB92的结构性质,并进行了比较,进而评估与底物结合后蛋白酶PB92在结构性特征以及稳定性上发生的一系列变化。实验结果表明,在动力学模拟过程中,有底物结合的蛋白酶PB92的构象比无底物结合的蛋白酶PB92的构象更加致密稳定,表现出符合“诱导契合”反应的模式。对未来更适用于洗涤用品工业的蛋白酶性能和结构的开发提供理论基础和指引。

A Modified Statistically Optimal Null Filter Method for Recognizing Protein-coding Regions

Computer-aided protein-coding gene prediction in uncharacterized genomic DNA sequences is one of the most important issues of bio- logical signal processing. A modified filter method based on a statistically optimal null filter （SONF） theory is proposed for recognizing protein-coding regions. The square deviation gain （SDG） between the input and output of the model is used to identify the coding regions. The effective SDG amplification model with Class I and Class II enhancement is designed to suppress the non-coding regions. Also, an evaluation algorithm has been used to compare the modified model with most gene prediction methods currently available in terms of sensitivity, specificity and precision. The performance for identification of protein-coding regions has been evaluated at the nucleotide level using benchmark datasets and 91.4%, 96%, 93.7% were obtained for sensitivity, specificity and precision, respectively. These results suggest that the proposed model is potentially useful in gene finding field, which can help recognize protein-coding regions with higher precision and speed than present algorithms.

A novel gain design method to improve the consensus performance of output-feedback multi-agent systems

This paper considers the consensus problem of a group of homogeneous agents. These agents are governed by a general linear system and can only directly measure the output, instead of the state. In order to achieve the consensus goal, each agent estimates its state through a Luenberger observer, exchanges its estimated state with neighbors, and constructs the control input with the estimated states of its own and neighbors. Due to the existence of observation and process noises, only practical consensus, instead of asymptotical consensus, can be achieved in such multi-agent systems. The performance of the achieved practical consensus can be measured by the ultimate mean square deviation of the states of agents. That performance is closely related to the observation gains of the state observers and the control gains of agents. This paper proposes a method to optimize such performance with respect to the concerned observation and control gains. That method starts with a set of feasible observation and control gains and formulates a group of linear matrix inequalities （LMIs）. Solving these LMIs gives some intermediate matrix variables. By perturbing observation and control gains, and the intermediate matrix variables, the original LMIs yield another group of LMIs, which can be solved to provide a descent direction of observation and control gains. Moving along that descent direction, observation and control gains can be improved to yield better performance and work as the starting point of the next iteration. By iteratively repeating this procedure, we can hopefully improve the consensus performance of the concerned multi-agent system. Simulations are done to demonstrate the effectiveness of the proposed method.

An analysis of nuclear charge radii based on the empirical formula

Several nuclear charge radii had been calculated based on the law of A1/3 and isospin dependence Z1/3 formula which had been used to describe the charge radii data. It is achieved that the isospin dependence Z1/3 formula is superior to the generally accepted A1/3 law through mean root square deviation analysis, that is, the Z1/3 formula is more effective to describe the charge radii data.

Quantitative standard of eco-compensation for the water source area in the middle route of the South-to-North Water Transfer Project in China

The Middle Route Project(MRP)of the Southto-North Water Transfer Scheme(SNWT)in China will require a very large financial expenditure to ensure the water supply and the associated water quality to northern China.An eco-compensation mechanism between the water service source areas and its beneficiaries is essential.This paper establishes an analytic framework of ecocompensation standard for the protection of the water source area,including both the calculation of ecocompensation based on opportunity cost method(OCM)and calculation of the burden sharing of eco-compensation between the water source area and the external water reception area based on the deviation square method(DSM).Taking Shiyan City,Hubei Province in China as a case study,our results show that the eco-compensation in the first-phase of MRP for the water source area in Shiyan,Hubei Province should be 1.63×10^(10) CNY,about four times of planned eco-construction investment budget(4.33×10^(9) CNY).In addition,the burden sharing of eco-compensation varied greatly in terms of different methods.It would be better to integrate the results of different single-factor burden sharing methods by determining the corresponding weighting coefficient with DSM and form one unanimous consent result by the interested parties.