Comparison of physics-based and data-driven modelling techniques for dynamic optimisation of fed-batch bioprocesses

The development of digital bioprocessing technologies is critical to operate modern industrial bioprocesses. This study conducted the first investigation on the efficiency of using physics-based and data-driven models for the dynamic optimisation of long-term bioprocess. More specifically, this study exploits a predictive kinetic model and a cutting-edge data-driven model to compute open-loop optimisation strategies for the production of microalgal lutein during a fed-batch operation. Light intensity and nitrate inflow rate are used as control variables given their key impact on biomass growth and lutein synthesis. By employing different optimisation algorithms, several optimal control sequences were computed. Due to the distinct model construction principles and sophisticated process mechanisms, the physics-based and the data-driven models yielded contradictory optimisation strategies. The experimental verification confirms that the data-driven model predicted a closer result to the experiments than the physics-based model. Both models succeeded in improving lutein intracellular content by over 40% compared to the highest previous record; however, the data-driven model outperformed the kinetic model when optimising total lutein production and achieved an increase of 40–50%. This indicates the possible advantages of using data-driven modelling for optimisation and prediction of complex dynamic bioprocesses, and its potential in industrial bio-manufacturing systems.     

Determination of reactor operation for the microbial hydroxylation of toluene in a two-liquid phase process

Summary Application of biotransformations to the synthesis of industrial chemicals is in part limited by a number of process challenges. We discuss the conversion of toxic, poorly water-soluble organic substrates by whole cells, using as an illustrative example the specific hydroxylation of toluene to toluenecis-glycol byPseudomonas putida UV4. Toxic effects may be eliminated through the introduction of tetradecane, to partition toluene away from the biocatalyst, to give product concentrations of 30–60 gL^–1, in a two-liquid-phase reactor. The operational limits of this system have been experimentally determined and are presented in the form of windows of operation.     

Soil Invertebrates as Bioindicators of Human Disturbance

The aim of this paper is to try to face up to the increasing demand for soil bioindicators to determine the state of health of the environment. Terrestrial ecosystems are contaminated by a wide range of pollutants originating from different sources and having very different distributions. Animals, plants, and, more generally, ecological community patterns seem to be able to register qualitative and quantitative environmental changes due to anthropogenic activities. A clear and accurate definitive generalization of the response of invertebrate populations to direct and indirect environmental stresses is very difficult; many variables can interact, such as the particular invertebrate species and/or the developmental stage exposed to the stress, the particular environmental stress due to different pollutants, and the environmental physical factors as well, sometimes intervening in complex patterns.     

Amino acid transport systems in animal cells: Interrelations and energization

After summarizing the discrimination of the several transport systems of neutral amino acids in the cell of the higher animal, I discuss here the ways in which 2 dissimilar transport systems interact, so that one tends to run forward for net entry and the other backwards for net exodus. An evaluation of the proposals for energization shows that uphill transport continues when neither alkali-ion gradients nor ATP levels are favorable. Evidence is presented that under these conditions a major contribution is made by another mode of energization, which may depend on the fueling of an oxidoreductase in the plasma membrane. This fueling may involve the export by the mitochondrion of the reducing equivalents of NADH by one of the known shuttles, e.g., the malate-aspartate shuttle. After depletion of the energy reseves in the Ehrilich cell by treating it with dinitrophenol plus iodoacetate concentrative uptake of test amino acids is restoration by pyruvate but in poor correlation with the restoration of alkali-ion gradients and ATP levels. This restoration by pyruvate but not by glucose is highly senstitive to rotenone. A combination of phenazine methosulfate and ascorbate will also produce transport restoration, before either the alkali-ion gradients or ATP levels have begun to rise. The restoration of transport applies to a model amino acid entering by the Na⁺-independent system, as well as to one entering by the principal Na⁺-dependent system, restoration being blocked by ouabain, despite the weak effect of ouabain on the alkali-ion gradients in the Ehrlich cell. Quinacrine terminates very quickly the uptake of model amino acids, before the alkali-ion gradients have begun to fall and before the ATP level has been halved. Quinacrine is also effective in blocking restoration of uphill transport by either pyruvate or the phenazine reagent. Preliminary results show that vesicles prepared from the plasma membrane of the Ehrlich cell quickly reduce cytochrome c or ferricyanide in the presence of NADH, and that the distribution of a test amino acid between the vesicle and its environment is influenced by NADH, quinacrine, and an uncoupling agent in ways consistent with the above proposal, assuming that a majority of the vesicles are everted.     

A simulation of T4 bacteriophage assembly and operation

A model is presented for the self-assembly and operation of a bacteriophage comparable with the T4 bacteriophage that infects Escherichia coli. The model treats protein molecules as simple units obeying the principle free energy minimization, and exhibiting the properties of quasi-equivalence and conformational switching. A computer program incorporating the model has been developed. The results of simulation using this program are presented.     

胭脂虫Dactylopius coccus Costa培育方法研究

【目的】为探索胭脂虫Dactylopius coccus高产培育新方法。【方法】胭脂虫的室内培养模式有采摘茎片培育模式和种植培育模式两种。本研究在采摘茎片模式下开展了培育环境构筑、平铺培育、接种方式、蔗糖培育等培育技术的研究;在种植模式下进行了接种方式、轮放培育和寄主高度控制的培育技术研究。【结果】探索出胭脂虫在两种模式下的新培育方法。【结论】在采摘茎片培育模式下,采用松针覆土保湿效果较好;平铺培育产量较高,值得推广;悬挂培育宜采用网兜内置谷草接种方式。蔗糖对胭脂虫有明显助食作用,喷洒适当浓度的蔗糖有助于提高胭脂虫的产量。在种植模式下,宜进行轮放培育,寄主植株高度控制在100 cm之内且茎片级数在4级之内,可避免植株倒伏及断离。采用纱网撒种方式,可节约接种环节中大量人力。     

广东医调委运行机制及其完善策略探讨

广东医调委经过近5年的探索与实践，开创了运用市场机制解决社会问题的新局面，并在过往调解实践和经验的基础上，创新和完善出一套有效解决医患纠纷的“保、调、赔、防、管”联合机制，对构建和谐医患关系和防范医疗风险具有积极的借鉴意义。     

眼科手术患者信息交互系统的开发和应用

眼病专科手术患者多、接台快，导致病房和手术室在接送手术患者时出现流程上不规范、不合理，出现差错和遗漏。为有效提高医疗、护理工作质量及工作效率，提高患者的满意度，为管理者和科研提供参考统计数据，利用信息化的技术，建立眼科手术患者信息交互系统，使医护共享有关数据，合理设计手术工作流程，实现科学化、规范化、信息化的手术患者全程管理目标。