基于遗传算法和支持向量机的乳杆菌发酵过程建模

由于生化反应过程的复杂性和高度非线性,多数简单的数学模型不能准确描述。该文基于Matlab软件,利用改进的支持向量机(υ-SVR)对植物乳酸杆菌发酵这一典型生化过程进行研究,应用遗传算法估计模型最优参数,建立植物乳杆菌的菌体密度预测模型。同时建立传统的logistic动力学模型以进行比较。结果表明,采用结合遗传算法的υ-SVR预测模型拟合误差小,皮尔森相关系数(R)更高,可以较好地预测乳酸杆菌的发酵过程,为其优化控制及放大提供依据。     

肝功能检验建议性报告软件临床分析管理的优势

介绍一种方便于临床分析、鉴别诊断和分析管理的临床检验专家系统。利用人工神经网络（Artificial Neural. Networks,ANN）挖掘患者基本信息和实验室数据,进行综合统计分析,对已确诊的患者（肝炎、肝癌、肝硬化和胆囊结石）的生化检验项目进行梳理,得出相应疾病生化指标的临床阳性预测值,然后以各项生化指标为多因素变量、诊断为输出变量建立ANN预测模型。另外抽取肝功异常并已明确诊断的患者60例进行生化指标测定,利用ANN系统,综合分析预测临床符合率,同时构建对初诊病人的树状筛查程序和直观判读报告软件的开发。利用专家诊断系统对肝脏疾病预测的准确率分别为：肝炎80.0%、肝硬化86.7%、肝癌66.7%和胆囊结石73.3%,优化后的报告格式直观反映患者的病情变化。借助于建议性报告软件可快速简易地作出对肝胆系统疾病鉴别诊断,达到医疗资源优化利用的目的。     

控制理论与生理控制系统(生理和生物化学系统分析)

控制理论正式用于生理学研究是从1948年控制论发表后开始的。控制论对控制理论在生理学中的应用起了很大的促进和指导作用。三十年来有关生理、生化系统分析,生理、生化系统模拟和数学模型的工作有很大的发展;但是与此同时也一直受到各方面的非议。应当意识到近年来,生理学有一种从注意生物体分子方面转向注意生物体本身的趋势,控制理论的应用在这种转变中多少可以起一些有益的桥梁作用。60年代末在生理学中出现了一种系统生理学观点,最近又出版了生物化学系统分析专著。系统生理学和生物化学系统分析的共同特点是它们坚持整体不等于其各组成部分的简单总和的观点,认为生命是一种系统的特征,研究这种特征超出了分子生物学和生物物理学的工作范围。今天的生理学属于比较成熟的科学,对更一般性的原理的探讨已经很有必要。生理学原理要能概括数理化和控制理论的有关内容,但还需要采用一般数理化和控制理论尚还不能确切表达其含义的生理学语言。     

杉木种子劣变某些生理生化过程的数学模型

建立了杉木种子劣变过程中SOD、质膜相对透性与不同生理生化过程的数学模型,并进行统计检验。结果表明：在高温下人工老化处理时间和不同湿度对不同生理生化过程行为模式均有不容忽视的.TTCH和SOD活性与老化时间存在着极为显著的线性负相关,相对电导率,可溶性糖及可溶性蛋白等与老化时间存在着较显著或显著或极显著的正相关。在高温状态下,高湿处理过的种子的质膜损伤速度、TTCH、SOD活性下降速率均大于低湿处理的。从数学模型及其比较看,SOD和质膜透性不仅对不同的生理生化过程的行为模式不同,而且在高温不同湿度条件下,对同一生理生化过程的行为模式亦发生变化。     

一类多分子生化反应系统的极限环

应用微分方程定性理论,研究了生化反应中一类多分子一级饱和反应的数学模型的极限环的存在性、不存在性和唯一性问题．     

一类一级饱和反应系统的极限环

本文研究生化反应中一类饱和反应的数学模型：应用微分方程定性理论,完整地解决了该系统极限环的存在性、唯一性和不存在性等问题．     

系统生物学中的数学模型方法及其应用

综述了当前在系统生物学研究领域中常用数学模型的建立和研究方法,介绍了通量平衡分析、基元通量模式、生化系统理论,以及代谢控制分析等模型的理论基础和发展背景,讨论了这些模型之间的联系、区别,以及适用范围,并总结了这些模型在分析代谢网络结构、优化代谢途径、指导菌种改进以提高琥珀酸、色氨酸、乙醇等重要化工品生产率和转化率中的实际应用。     

生态系统的信息传递及其利用

信息传递是生态系统的基本功能之一。在传递过程中伴随着一定的物质和能量的消耗。但是信息传递不象物质流那样是循环的,也不象能流那样是单向的,而往往是双向的,有从输入到输出的信息传递,也有从输出向输入的信息反馈。按照控制论的观点,正由于这种信息流,才使生态系统产生了有一定范围的自动调节机制。生态系统中包含多种多样的信息,大致上可以分为物理信息、化学信息、营养信息和行为信息。下面简单介绍各类信息及其在实践上的应用。 (一)物理信息及其应用生态系统中的各     

植物线粒体的结构和机能

近年来,由于电子显微鏡、超速离心法等新技术的应用,关于細胞亚显微的结构和生理功能等方面的研究获得了很大的进展。例如,目前已經确定,存在于細胞貭內的线粒体是一种結构极为复杂的“生化器”,这种生化器在細胞完成生物氧化和能量轉換的过程中具有非常重要的作用。     

丝状真菌形态控制及其在发酵过程优化中的应用

丝状真菌广泛用于发酵产业,在液体深层发酵过程中,其生长形态与产物种类及产量间存在重要关联,成为发酵过程调控的热点。采用数学模型解释丝状真菌的形态发育与调控机制,是近年来工程学界颇为关注的研究手段。本文结合自己的工作着重解释丝状真菌各种生长形态的生长机理及形态发育的数学描述方式,以及如何采用数学模型描述丝状真菌发酵过程中产物、形态及环境的关联,最终实现形态的控制,完成生物发酵过程优化。具体包括:1)丝状真菌的生长机制;2)形态发育数学模型在发酵过程优化中的应用;3)控制丝状真菌形态的策略。     

嗜热链球菌高密度发酵过程的优化方案探讨

本研究介绍了嗜热链球菌（Streptococcus thermophilus）高密度发酵过程的优化方案。首先从培养基优化方案入手,讨论了单因素法与正交实验法在培养基优化过程中的利弊。第二,介绍了培养条件以及发酵过程的优化,包括pH、培养温度、搅拌转速、接种量和培养时间。第三,介绍了菌体的后处理过程,包括降温处理、超声解链、离心冻干。     

On-line optimization of recombinant product in a fed-batch bioreactor

In this paper, an efficient scheme for on-line optimization of a recombinant product in a fed-batch bioreactor is presented. This scheme is based on the parametrization of the system states and the elimination of a subset of the dynamic equations in the mathematical model of the fed-batch bioreactor. The fed-batch bioreactor considered here involves the production of chloramphenicol acetyltransferase (CAT) in a genetically modified E. coli. The optimal inducer and the glucose feed rates are obtained using the proposed optimization approach. This approach is compared with the traditional optimization approach, where all the states and the manipulated variables are parametrized. The approach presented in this paper results in a 5-fold improvement in the computational time for the recombinant product optimization. The optimization technique is employed in an on-line optimization scheme, when parametric drift and a disturbance in the manipulated variable is present. Feedback from the process is introduced through resetting the initial conditions of the model and through an observer for estimating the time varying parameter. The simulation results indicated improvement in the amount of product formed, when the optimal profile is regenerated during the course of the batch.     

退火遗传算法及其应用

将模拟退火方法引入遗传算法中,对非线形问题进行优化。该算法克服了ＳＧＡｓｒ 的过早收敛的问题,并解决了染色体样性要求。最后将该算法应用于解决水资源优化分配的问题中,优化结果同样具备上述特点。     

Performance and optimization of biological nitrogen removal process enhanced by anoxic/oxic step feeding

The aim of this paper is to investigate the performance and optimization of an biological nitrogen removal process enhanced by the anoxic/oxic four stages step-feeding process under sufficient/insufficient influent carbon source. The concept of influent flow distribution ratio (λ) was introduced according to the performance of the step-feed process for inflow splitting and volume distribution. Under the condition of sufficient carbon, the uniform influent flow distribution ratio was proposed from the standpoint of which is easy for process control, operation optimization and management. Under the condition of different influent C/N ratios, the optimal influent flow distribution ratios (λ_opt) were determined, by trial-and-error method. The results showed that more than 95.81% of the total nitrogen removal efficiency could be achieved by step-feeding process with a fixed influent C/N ratio. A model was introduced to derive the relationships of total nitrogen removal efficiency with λ and influent C/N ratio. When the influent carbon source was insufficient, however, the λ_opt between two adjacent stages should not be uniform. The results also showed that the four-stage step-feeding process with λ_opt of 2.0:2.1:2.5:3.4 could significantly improve the total nitrogen removal efficiency. The results obtained in this study will help to optimize the design and the operation of BNR systems.     

制备色谱操作条件的优化

色谱优化是蛋白质生产制备工艺开发中必不可少的一步。本文讨论了不同的优化目标 ,介绍了目前常见的优化方法 ,特别是实际应用中的原则及实验方法 ,对涉及优化的基本概念也做了说明。     

Optimal feed policy for fed-batch fermentation of ethanol production by Zymomous mobilis

Optimal feed control for the fed-batch fermentation process of ethanol production is studied. Additional inequality constraints are introduced in this optimization problem to assure the optimal solution in a reality region. Introducing an updating rule of augmented Lagrange multipliers to handle these inequality constraints, iterative dynamic programming can be used in a straightforward manner for the optimization of fed-batch fermentors. To obtain more accurate solution a method of sequential quadratic programming can be used to solve this problem again. As a result of this optimal control, the maximum production at final time is very close to the theoretical yield. Although sequential quadratic programming can be rapid convergence to the optimal solution, but very good initial starting points has to be used to ensure obtaining the global optimum. Experimental works were used to validate this study. The simulated results could fit the experiments satisfactorily.     

Optimal in-vitro expansion of chondroprogenitor cells in monolayer culture

A continuous production of large quantities of chondroprogenitor cells for the manufacture of engineered cartilage tissue products is required. Expansion of the cell population in vitro has become an essential step in the process of tissue engineering of articular cartilage and the optimization of the culture conditions is a fundamental problem that needs to be addressed. The analysis of both seeding density and passage length was considered crucial in the optimization of expansion processes, and their correct selection should be taken as a requisite to establish culture conditions for monolayer systems. The determination of the optimal seeding density and the corresponding passage length for cell expansion in a serial passaging operation was found to be a compromise between growth kinetics and process time. This optimal determination was carried out using a mathematical approach that led to values of 10(4) cell/cm(2) for seeding density and 73 h for passage length. Additional considerations concerning the running cost of the process were introduced. Although the optimal passage length gave the desired expansion factor in a minimum process time, the selection of an alternative value of 120 h was shown to reduce the cost of the expansion process in more than 60%. The optimization approach presented will contribute to the development of feasible large scale expansion operations of chondroprogenitor cells required by the cartilage tissue engineering industry.     

代谢工程及其在产苯丙氨酸基因工程菌构建中的应用

本文对代谢工程的发展状况从研究方法,在医药、农业及环保中应用等几方面做了概括地介绍;从宿主的选择,加速限速反应,改变代谢流和生产程序的优化几方面较为详细地评述了代谢工程在苯丙氨酸基因工程菌构建方面的应用,并对代谢工程的未来发展进行了展望。     

生态系统管理的多目标体系和方法

20世纪90年代以来,人们开始采用“生态系统管理”这种基于生态系统原理的综合方法管理自然资源和生态环境,促进人类与自然的和谐发展。然而,生态系统自身的复杂性、动态性及不确定性特点使得“生态系统管理”难以形成明确的定义和方法体系,系统的多重尺度和目标也增加了管理的难度。近20年兴起的系统工程主要针对大规模复杂系统进行研究,实现系统的总体优化。多目标决策和决策支持系统是系统工程的常用技术方法,生态系统管理是“基于目标”的管理模式。本文概述了生态系统管理的概念和要素,从构建管理体系的角度着重阐述了生态系统管理目标体系的结构、构建过程及目标间的相互关系,针对生态系统的复杂特性探讨了多目标决策方法和决策支持系统在生态系统管理中的应用,以期能够对形成具有普遍意义和实际操作性的生态系统管理方法体系起到借鉴作用。     

Application of the transition time of metabolic system as a criterion for optimization of metabolic processes

Transition time of metabolic systems in introduced as a suitable optimization criterion for biotechnological processes in which it is desirable to reduce the lag time and minimize the mass contained within the system. Lag time is the time needed for the system to attain the steady state. Results obtained from the sensitivity analysis of this steady state response are presented within the metabolic control analysis and applied to 3 case studies. In all of them the information provided by the transition time control profile allows the implementation of a strategy for biotechnological manipulations aimed at the improvement of the process. (c) 1994 John Wiley & Sons, Inc.