关于数量化Ⅰ方法的自变量之间交互作用计算

自变量之间存在交互作用时,在应用数量化方法Ⅰ时如何计算自变量间的交互作用建立数量化方程。     

微波协同酶法提取平菇柄多糖的工艺研究

为优化微波协同酶法提取平菇柄多糖的工艺条件,在单因素试验的基础上,选择提取时间、微波功率以及液料比为自变量,多糖得率为响应值,采用中心组合设计的方法,研究各自变量及其交互作用对多糖得率的影响。利用响应面分析方法,模拟得到二次多项式回归方程的预测模型,并确定平菇柄多糖提取工艺的最佳条件为:微波功率420 W,提取时间8 min,液料比55:1,在此条件下,最大得率达到6.05%。     

响应面法优化微波辅助提取发酵虫草菌丝体多糖工艺

为优化发酵虫草菌粉多糖的微波辅助提取工艺,在单因素实验基础上,以液固比、微波功率以及提取时间为自变量,多糖提取率为响应值,采用中心组合设计的方法,研究各自变量及其交互作用对多糖提取率的影响。利用SAS软件和响应面分析相结合的方法对发酵虫草菌粉多糖的微波辅助提取工艺进行优化,确定了微波辅助提取多糖的最佳条件：液固比值12．2,微波功率650．5W,提取时间11．8min,在此条件下,多糖提取率达到6．41％。采用此法提取的虫草菌丝体多糖,当质量浓度为1mg／mL时,对二苯代苦味肼基自由基（DPPH）清除率达到76％。     

响应面分析法优化超声提取蓖麻碱工艺

以蓖麻叶为原料,对蓖麻碱的超声提取工艺优化进行研究,在单因素试验的基础上,选择超声时间、超声功率、料液比为自变量,以蓖麻碱提取率为影响值,采用响应面试验设计方法,研究各自变量及其交互作用对蓖麻碱提取率的影响。利用Design Expert8软件得到回归方程得模型并进行响应面分析,确定超声提取蓖麻碱的最佳工艺条件为料水比为1∶25 g/mL,超声时间为103.03 min,超声功率为621.05 W,此条件下蓖麻碱的提取率为2.63‰。     

响应面法优化超声辅助提取宣木瓜总皂苷提取工艺研究

对宣木瓜总皂苷的超声辅助提取工艺优化进行研究.在单因素试验基础上,选择提取时间、温度、乙醇浓度和料液比为自变量,以宣木瓜总皂苷得率为响应值,采用Central Composite Design试验设计方法,研究各自变量及其交互作用对宣木瓜总皂苷提取率的影响.利用Design Expert软件得到回归方程的预测模型并进行响应面分析,确定超声辅助提取宣木瓜总皂苷的最佳条件为时间61.69 min,温度62.34℃,乙醇浓度70.49％,料液比1∶30.57 g/mL,在此条件下,总皂苷提取率达到1.55％.验证实验表明,所得模型方程能较好地预测实验结果.     

提示线索位置影响斜线任务中Flanker与Simon冲突间的交互作用

目的：本文探讨Flanker与Simon冲突间的交互作用,以及提示线索位置对其的影响。方法：实验通过将Flanker与Simon两种冲突融合于同一范式,采用斜线任务提高冲突难度,设计上下、左右和斜线三种位置提示线索,并根据其类型的不同将被试分为三组。统计分析冲突下的正确率与反应时数据,用重复测量方差分析得出两种冲突的交互作用,以及不同位置线索对其的影响。结果：总的来说,Flanker冲突和Simon冲突在反应时和正确率上都有显著效应。从正确率来看,上下位置线索时,Flanker和Simon冲突之间的交互作用显著;左右位置线索时交互作用不显著;而斜线位置线索时交互作用边缘显著。从反应时来看,对于三种位置线索,两种冲突间的交互作用都不显著。结论：融合在同一任务中的Flanker冲突与Simon冲突之间是否存在交互作用与提示线索的位置有关。     

响应面法优化微波提取绞股蓝愈伤组织中人参皂苷Rb1的工艺研究

以绞股蓝愈伤组织为原料,优化绞股蓝人参皂苷Rb1的微波提取工艺,在单因素试验的基础上,选择液料比、微波功率和微波处理时间为自变量,人参皂苷Rb1为响应值,采用响应曲面法设计、分析研究各自变量及其交互作用对人参皂苷Rb1提取率的影响.利用响应面分析方法,模拟得到二次多项式回归方程的预测模型,并确定人参皂苷Rb1微波辅助提取工艺的最佳条件为：料液比1：20（g/mL）,处理时间6 min,微波功率200 W.在此最佳工艺条件下,人参皂苷Rb1得率为3.95 mg/g.     

超临界CO_2流体萃取苦瓜总黄酮工艺及其抗氧化活性

利用响应面法优化超临界CO2萃取苦瓜总黄酮的工艺参数,在单因素实验基础上,以萃取时间、萃取温度及萃取压力为自变量,总黄酮提取率为响应值,采用中心组合设计的方法,研究各自变量及其交互作用对总黄酮提取率的影响。结果表明,3个因素对总黄酮提取率的影响大小依次为萃取压力、萃取温度、萃取时间。利用SAS软件和响应面分析相结合的方法模拟得到二次多项式回归方程的预测模型,确定最佳工艺条件:采用无水乙醇为夹带剂(4.0 mL/g),萃取压力33.4 MPa、萃取温度46℃、萃取时间53.2 m in。此条件下,苦瓜总黄酮提取率达到84.3%。抗氧化实验表明:超临界CO2萃取能较好保留苦瓜总黄酮的抗氧化活性,采用超临界CO2萃取法提取的苦瓜总黄酮具有较强的抗氧化活性,当质量浓度为1 mg/mL时,对DPPH自由基的清除能力与Vc相当,清除率达到93.1%。     

随机森林是特点鲜明的模型,不是万能的模型

随机森林(Random forest)模型在2001年发表后得到广泛的关注。由于随机森林可以进行回归和判别等多种统计分析,而且不受正态性、方差齐性和自变量独立性等参数检验的前提条件的制约,其应用日益普遍,有被看作万能模型的趋势。实际上,随机森林是一种特点鲜明的模型,应用局部优化拟合观察值,在分析有偏效应关系的数据时,其结果往往不准确。本文以蝉科(Cicadidea)物种的分布数据为例,比较了随机森林在回归分析时与多元线性回归、广义可加模型和人工神经网络模型的差别,在判别分析时与线性判别分析的差别,强调了随机森林预测时的碎片化特点。结果显示随机森林在处理有多元共线性和交互作用的数据时,以及在判别分析时,其准确率最高。鉴于随机森林的局限性,建议做数据分析时选择多种模型进行比较。文中的R语言代码可为研究者提供参考。     

木荷家系生长性状的反向逐步剔除法回归分析

选用广东省东江林场和梅南林场20个木荷Schima superba优树自由授粉家系子代,开展生长性状测定试验,分析3、6、9和11年生树高、胸径/地径和单株材积。结果表明,木荷9个生长性状在家系水平上和不同地点间均存在极显著差异,且家系与地点间具有显著的交互作用。以11年生单株材积为因变量,3~9年树高与地径/胸径为自变量,运用反向逐步剔除法,构建群体水平与家系水平的单地点和多地点多元线性回归方程63个,全部方程整体上均达到极显著检验水平,但各方程的截距、自变量数量、组成、系数和决定系数均存在明显差异,说明木荷生长性状多元线性回归方程宜分家系和分地点单独构建。预测木荷家系11年生单株材积时,群体水平单地点或多地点回归模型可实现普通准确性,单个家系单地点回归模型可实现更高准确性。     

Small molecules that target phosphorylation dependent protein–protein interaction

Protein–protein interaction is one of the key events in the signal transduction pathway. The interaction changes the conformations, activities, localization and stabilities of the proteins, and transduces the signal to the next step. Frequently, this interaction occurs upon the protein phosphorylation. When upstream signals are stimulated, protein kinase(s) is/are activated and phosphorylate(s) their substrates, and induce the phosphorylation dependent protein–protein interaction. For this interaction, several domains in proteins are known to specifically recognize the phosphorylated residues of target proteins. These specific domains for interaction are important in the progression of the diseases caused by disordered signal transduction such as cancer. Thus small molecules that modulate this interaction are attractive lead compounds for the treatment of such diseases. In this review, we focused on three examples of phosphorylation dependent protein–protein interaction modules (14-3-3, polo box domain of Plk1 and F-box proteins in SCF ubiquitin ligases) and summarize small molecules that modulate their interaction. We also introduce our original screening system to identify such small molecules.     

Study of mechanisms of ceruloplasmin interaction with monolayer distearoyl phosphatidylcholine membranes

A mechanism of basic serum blood antioxidant ceruloplasmin interaction with membrane surface of the monolayer from distearoyl phosphatidylcholine was investigated. It was shown that an important component of this interaction is an arising of a bond within negatively charged side chains of ceruloplasmin aminoacids and phosphate groups of monolayer film and change of packing density due to this interaction.     

A high-throughput screening method for small-molecule inhibitors of the aberrant mutant SOD1 and dynein complex interaction

Aberrant protein-protein interactions are attractive drug targets in a variety of neurodegenerative diseases due to the common pathology of accumulation of protein aggregates. In amyotrophic lateral sclerosis, mutations in SOD1 cause the formation of aggregates and inclusions that may sequester other proteins and disrupt cellular processes. It has been demonstrated that mutant SOD1, but not wild-type SOD1, interacts with the axonal transport motor dynein and that this interaction contributes to motor neuron cell death, suggesting that disrupting this interaction may be a potential therapeutic target. However, it can be challenging to configure a high-throughput screening (HTS)-compatible assay to detect inhibitors of a protein-protein interaction. Here we describe the development and challenges of an HTS for small-molecule inhibitors of the mutant SOD1-dynein interaction. We demonstrate that the interaction can be formed by coexpressing the A4V mutant SOD1 and dynein intermediate complex in cells and that this interaction can be disrupted by compounds added to the cell lysates. Finally, we show that some of the compounds identified from a pilot screen to inhibit the protein-protein interaction with this method specifically disrupt the interaction between the dynein complex and mtSOD1 but not the dynein complex itself when applied to live cells.     

Mapping of the physical interaction between the intracellular domains of an inwardly rectifying potassium channel, Kir6.2

The amino-terminal and carboxyl-terminal domains of inwardly rectifying potassium (Kir) channel subunits are both intracellular. There is increasing evidence that both of these domains are required for the regulation of Kir channels by agents such as G-proteins and nucleotides. Kir6.2 is the pore-forming subunit of the ATP-sensitive K(+) (K(ATP)) channel. Using an in vitro protein-protein interaction assay, we demonstrate that the two intracellular domains of Kir6.2 physically interact with each other, and we map a region within the N terminus that is responsible for this interaction. "Cross-talk" through this interaction may explain how mutations in either the N or C terminus can influence the intrinsic ATP-sensitivity of Kir6.2. Interestingly, the "interaction domain" is highly conserved throughout the superfamily of Kir channels. The N-terminal interaction domain of Kir6.2 can also interact with the C terminus of both Kir6.1 and Kir2.1. Furthermore, a mutation within the conserved region of the N-terminal interaction domain, which disrupts its interaction with the C terminus, severely compromised the ability of both Kir6.2 and Kir2.1 to form functional channels, suggesting that this interaction may be a feature common to all members of the Kir family of potassium channels.     

Binding of IRBIT to the IP3 receptor: determinants and functional effects

IRBIT has previously been shown to interact with the inositol 1,4,5-trisphosphate (IP3) receptor (IP3R) in an IP3-sensitive way. So far it remained to be elucidated whether this interaction was direct or indirect, and whether it was functionally relevant. We now show that IRBIT can directly interact with the IP3R, and that both the suppressor domain and the IP3-binding core of the IP3R are essential for a strong interaction. Moreover, we identified a PEST motif and a PDZ-ligand on IRBIT which were critical for the interaction with the IP3R. Furthermore, we identified Asp-73 as a critical residue for this interaction. Finally, we demonstrated that this interaction functionally affects the IP3R: IRBIT inhibits both IP3 binding and IP3-induced Ca2+ release.     

Tourism and Marine Wildlife: The Wild Dolphins of Tangalooma,Australia: A Case Report

Abstract

Tourist interest in experiencing marine wildlife in their natural environment is growing. In particular, opportunities for interaction with marine mammals such as dolphins are becoming increasingly popular. Such interaction between humans and solitary dolphins has occurred throughout history; however, the dolphins at Monkey Mia in Western Australia are the only recorded group of dolphins which regularly interact with tourists. A previously unreported case of tourist-dolphin interaction is being developed at Tangalooma in Queensland, Australia. The development of this program is outlined in this paper and the current management of this interaction is considered.     

Ab initio calculations on hidden modulators of theta class glutathione transferase activity

The glutathione transferases decrease the pKa of glutathione, allowing its deprotonation and the formation of the more reactive thiolate anion. The thiolate is maintained in the active site through a weak conventional hydrogen bond first sphere interaction donated by a Tyr hydroxyl in the Alpha, Mu, Pi, and Sigma glutathione transferase classes that can be modified by other second sphere or indirect thiolate contacts. However, the Theta and Delta class isoforms use a Ser hydroxyl for stabilizing the GSH thiolate, and as such, have a different chemical system compared with that of the Tyr possessed by other classes. We have used high level ab initio methods to investigate this interaction by using a simple methanol methanethiol system as a model. The hydrogen bond strength of this initial first sphere interaction was calculated to be less than that of the Tyr interaction. A putative second sphere interaction exists in the Theta and Delta class structures between Cys or Ser-14 and Ser-11 in the mammalian Theta subclass 1 and 2, respectively. The effect of this interaction on the first sphere interaction has also been investigated and found to significantly increase the energy of the bond.     

Specific and nonspecific interactions of antibodies and immunoglobulins with antigens and the methods of analysis of these interactions

The problem of specific and nonspecific interaction of serum immunoglobulins and antigens was considered. It was shown that high-sensitive methods allow to reveal low-affinity non-specific interaction of immunoglobulins and antigens. If the concentration of the specific antibodies in a studied sample of serum is low, the non-specific interaction of serum immunoglobulins may exceed substantially the effect of specific reaction. In this case the obtained results could be misinterpreted. In this connection the conclusion has been done that in such a case it is necessary to take into account the capability of serum immunoglobulins to interact non-specifically with antigens and to discriminate between specific and non-specific interaction. The methods of the diminishing the non-specific interaction are suggested.     

Red blood cell aggregation and dissociation in shear flows simulated by lattice Boltzmann method

In this paper we develop a lattice Boltzmann algorithm to simulate red blood cell (RBC) behavior in shear flows. The immersed boundary method is employed to incorporate the fluid-membrane interaction between the flow field and deformable cells. The cell membrane is treated as a neo-Hookean viscoelastic material and a Morse potential is adopted to model the intercellular interaction. Utilizing the available mechanical properties of RBCs, multiple cells have been studied in shear flows using a two-dimensional approximation. These cells aggregate and form a rouleau under the action of intercellular interaction. The equilibrium configuration is related to the interaction strength. The end cells exhibit concave shapes under weak interaction and convex shapes under strong interaction. In shear flows, such a rouleau-like aggregate will rotate or be separated, depending on the relative strengths of the intercellular interaction and hydrodynamic viscous forces. These behaviors are qualitatively similar to experimental observations and show the potential of this numerical scheme for future studies of blood flow in microvessels.     

Molecular Mechanism behind Rotavirus NSP1-Mediated PI3 Kinase Activation: Interaction between NSP1 and the p85 Subunit of PI3 Kinase

Our previous study had reported on the interaction of rotavirus NSP1 with cellular phosphoinositide 3-kinase (PI3K) during activation of the PI3K pathway (P. Bagchi et al., J. Virol. 84:6834–6845, 2010). In this study, we have analyzed the molecular mechanism behind this interaction. Results showed that this interaction is direct and that both α and β isomers of the PI3K regulatory subunit p85 and full-length NSP1 are important for this interaction, which results in efficient activation of the PI3K/Akt pathway during rotavirus infection.