混沌时间序列及MATLAB仿真实现

在非线性系统中,存在着一种非常特殊的系统,即混沌系统,是一种介于确定关系和随机关系之间的状态。文章首先阐述了混沌的基本概念,然后对嵌入维数m和延迟时间τ这两个参数的选取方法做了简要介绍;列举了几个典型的混沌模型,并运用MATLAB软件对其进行仿真实现。     

A multiple-dose pharmacokinetics of polyethylene glycol recombinant human interleukin-6 (PEG-rhIL-6) in rats

Radiation therapy has been widely applied in cancer treatment. However, it often causes thrombocytopenia (deficiency of white blood cells) as an adverse effect. Recombinant human interleukin-6 (rhIL-6) has been found to be a very effective way against this thrombocytopenia, but IL-6 has low stability in blood, which reduces its efficacy. To increases the stability and half-life of rhIL-6, it was modified by polyethylene glycol (PEG). The pharmacokinetics and the tissue distribution of PEG-rhIL-6 labeled with ¹²⁵I were examined after subcutaneous injection in rats. The pharmacokinetic pattern of PEG-rhIL-6 was defined with linear-kinetics, and we fitted a one-compartment model with half-lives of 10.44–11.37 h (absorption, t _{1/2K a}) and 19.77–21.53 h (elimination, t _1/2Ke), and peak concentrations at 20.51–21.96 h (t _peak) in rats. Half-lives and t _peak of PEG-rhIL-6 were longer than those of rhIL-6 previously reported. In the present study, for deposition of PEG-rhIL-6 in rats, the tissue distribution examination showed that blood was the major organ involved, rather than liver. However, as to the elimination of PEG-rhIL-6, the major organ was the kidney. The excretion fraction of the injection dose recovered from urine was 23.32% at 192 h after subcutaneous administration. Less than 6% of PEG-rhIL-6 was eliminated via the feces at 192 h. These results indicate that PEG-rhIL-6 is a good candidate drug formulation for patients with cancer.     

Preparation of glucosamine by hydrolysis of chitosan with commercial α-amylase and glucoamylase

Objective  

In order to overcome the defects of chemical hydrolysis approach to prepare glucosamine, an enzymatic hydrolysis method was developed.     

Evaluation of the antioxidant effects of four main theaflavin derivatives through chemiluminescence and DNA damage analyses

Theaflavins (TFs) are the dimers of a couple of epimerized catechins, which are specially formed during black tea fermentation. To explore the differences among four main TF derivatives (theaflavin (TF₁), theaflavin-3-gallate (TF₂A), theaflavin-3′-gallate (TF₂B), and theaflavin-3,3′-digallate (TF₃)) in scavenging reactive oxygen species (ROS) in vitro, their properties of inhibiting superoxide, singlet oxygen, hydrogen peroxide, and the hydroxyl radical, and their effects on hydroxyl radical-induced DNA oxidative damage were systematically analyzed in the present study. The results show that, compared with (−)-epigallocatechin gallate (EGCG), TF derivatives were good antioxidants for scavenging ROS and preventing the hydroxyl radical-induced DNA damage in vitro. TF₃ was the most positive in scavenging hydrogen peroxide and hydroxyl radical, and TF₁ suppressed superoxide. Positive antioxidant capacities of TF₂B on singlet oxygen, hydrogen peroxide, hydroxyl radical, and the hydroxyl radical-induced DNA damage in vitro were found. The differences between the antioxidant capacities of four main TF derivatives in relation to their chemical structures were also discussed. We suggest that these activity differences among TF derivatives would be beneficial to scavenge different ROS with therapeutic potential.     

Characterization of (68)Zn uptake, translocation, and accumulation into developing grains and young leaves of high Zn-density rice genotype

Zinc (Zn) is an essential micronutrient for humans, but Zn deficiency has become serious as equally as iron (Fe) and vitamin A deficiencies nowadays. Selection and breeding of high Zn-density crops is a suitable, cost-effective, and sustainable way to improve human health. However, the mechanism of high Zn density in rice grain is not fully understood, especially how Zn transports from soil to grains. Hydroponics experiments were carried out to compare Zn uptake and distribution in two different Zn-density rice genotypes using stable isotope technique. At seedling stage, IR68144 showed higher ⁶⁸Zn uptake and transport rate to the shoot for the short-term, but no significant difference was observed in both genotypes for the long-term. Zn in xylem sap of IR68144 was consistently higher, and IR68144 exhibited higher Zn absorption ratio than IR64 at sufficient (2.0 μmol/L) or surplus (8.0 μmol/L) Zn supply level. IR64 and IR68144 showed similar patterns of ⁶⁸Zn accumulation in new leaves at seedling stage and in developing grains at ripening stage, whereas ⁶⁸Zn in new leaves and grains of IR68144 was consistently higher. These results suggested that a rapid root-to-shoot translocation and enhanced xylem loading capacity may be the crucial processes for high Zn density in rice grains.     

会话含义实现及解读

日常对话中,语言字面意思与说话人真实意图通常有一定距离,会话含义研究由此开始。格赖斯通过合作原则来解释会话含义产生方式,利奇、布朗和列文森则提出礼貌理论来阐释人们违反或遵守合作原则的原因。本文通过分析合作原则、礼貌原则、语境及非语言行为来分析会话含义的实现及解读,从而促进交际双方对话语含义的理解。     

复辞辞格形成的多样性

与其他辞格相比,复辞未得到应有的重视,但是自先秦开始到现在,这种辞格的应用一直非常广泛。多种修辞格如转类、拈连、对偶、同异、排比、双关、顶针、回文等均可以形成复辞,显示了复辞形成的独特性。     

区域内校际间高考成绩评价的探索与实践——以深圳部分学校2010年高考成绩为例

由于学校之间生源质量和考生规模等方面的客观差异,以升学率或者考上清华、北大的人数评判学校的高考成绩是不科学和不公平的。要在不同的学校之间进行高考成绩的比较或评价,较为科学和公平的思路与方法是将高考结果与其高一生源质量进行比较,着重从学校的“教育教学培养提升能力”来评价,主要的分析和评价指标有百分位变化指数、目标达成度、同名次段人数保持率、相近质量生源考生上线率和平均分等。     

Screening study of transition metal oxide catalysts supported on ceria-modified titania for catalytic oxidation of toluene

Six transition metal oxides were added in ceria-modified titania using a sol-gel method for catalytic oxidation of toluene. An MnOx based catalyst was found to be the most active one, with which toluene could be decomposed completely at 200 °C. The greatest Mn/Ti and molar ratio of the mobile oxygen to the total oxygen concentration, together with a large surface area and a low reduction peak-starting temperature, would result in its best activity in toluene oxidation.     

“It Lets Me Fight the Bad Guys”: An Exploration Into the Factors Predicting Enjoyment of Violent Video Games

In an exploratory survey that sampled video gamers, participants were asked to indicate why they enjoy playing their favorite video game. On the basis of ESRB ratings, we compare those whose favorite game is violent to those whose favorite game is nonviolent. Consistent with self-determination theory, the findings suggest need for autonomy and competence are important motivating factors. However, the findings also suggest fans of violent games differed from fans of nonviolent games in the degree to which arousal, liking violence, playing the vicarious hero, and playing the vicarious villain drive enjoyment. Furthermore, being able to play the hero and “fight bad guys” was a significant predictor of enjoyment of violent games. Implications for self-determination theory and theories of media enjoyment are discussed.