Optimal response in siso ripple-free deadbeat systems

The ripple-free deadbeat control problem for SISO plants subjected to arbitrary reference signals is considered. The trade-off between the settling time and the integral square error between the system output and reference signal is investigated. Given a specific order of the controller, it is shown how to design an optimal ripple-free deadbeat controller. An illustrative example is presented to show the feasibility of the proposed algorithm.     

Measurement of axial edge lift of rigid corneal lenses*

A simple but reliable method was used to measure the axial edge lift at the total diameter over a range of back optic zone radii of several proprietary designs of rigid gas-permeable corneal lens. One of these was found to have a constant axial edge lift construction.     

New approaches to QSAR: Neural networks and machine learning

Summary Neural networks and machine learning are two methods that are increasingly being used to model QSARs. They make few statistical assumptions and are nonlinear and nonparametric. We describe back-propagation from the field of neural networks, and GOLEM from machine learning, and illustrate their learning mechanisms using a simple expository problem. Back-propagation and GOLEM are then compared with multiple linear regression (using the parameters and their squares) on two real drug design problems: the inhibition ofEscherichia coli dihydrofolate reductase (DHFR) by pyrimidines and the inhibition of rat/mouse tumour DHFR by triazines.     

汽车后送伤员附加装置隔振设计

采用钢丝绳隔振器设计了运输车后送伤员附加装置的隔振结构，并进行了隔振性能试验。5名受试者的试验结果表明，隔振装置的隔振性能良好，可衰减40％—70％的振动能量。本文为运输车后送伤员附加装置的隔振设计提供了一种新方法。     

正交设计在确定混合血清法检测丙型肝炎抗体实验条件中的应用

目的探讨封闭温度、时间、ＢＳＡ浓度、Ｔｗｅｎ２０浓度及混合标本个数５因素各２水平对混合血清法检测抗－ＨＣＶ的影响。方法应用正交设计的方法进行实验分组，采用ＥＩＡ法检测抗－ＨＣＶ。结果封闭条件为０．５％ＢＳＡ，３７℃，３０ｍｉｎ；洗涤液为０．１５％Ｔｗｅｅｎ２０，混合标本个数为５。采用正交设计的实验方法可减少７５％的实验次数。结论在进行多因素的实验研究时，正交设计是一种高效的设计方法。     

三种泻心汤及其类方不同配伍对正常大鼠胃粘液成分的影响

目的:探讨半夏泻心汤及其类方不同配伍对正常大鼠粘液含量的影响.方法:用均匀设计法对半夏泻心汤及其类方进行组方药量变化,以胃粘液含量为药理学指标,对所得的药理实验数据进行逐步回归分析.结果:与胃粘液含量关联度最大的为黄连,可以显著降低其含量,其次对半夏、大枣和甘草的交互项,可增加胃粘液含量.药物之间存在复杂的交互作用.结论:均匀设计为研究类方配伍提供了一种可供参考的试验设计方法.     

Basic sciences in problem-based learning and conventional curricula: students' attitudes

The purpose of this study was to compare the attitudes toward basic sciences of students in a preclinical problem-based curriculum and a conventional lecture-based curriculum at the end of their second year of medical school. The results showed that the PBL class had more positive attitudes toward basic sciences than students in the conventional class. These results may reflect a learning environment where students meet many scientist role models as teachers and where basic science is learnt in the context of clinical problems.     

Operative treatment of intertrochanteric hip fractures: an overview of modern advances and techniques

Hip fractures have been one of the most studied injury pattern in adults. The number of hip fractures is increasing exponentially; furthermore, the cost of treatment places great economic strain on society. There have been recent developments in hip-fracture treatment, particularly involving the intertrochanteric region, with emphasis on deformity prevention to try to optimize patient functional outcomes. In this article, we outline some of these developments with an emphasis on changes in implant design.     

W／O／W型甘草酸单铵盐口服复乳的处方设计及其理化特性研究

采用均匀设计，以乳剂的稳定性参数为考察指标，考察了初乳乳化剂、复乳乳化剂、乳化时间等因素对复乳稳定性的影响；筛选出Ｗ／Ｏ／Ｗ型甘草酸单铵盐口服复乳的优化处方和工艺，并对复乳的主要理化特性和物理稳定性进行了考察。     

33 factorial design-based optimization of the formulation of nitrofurantoin microcapsules

A microcapsule form of nitrofurantoin was prepared by a simple coacervation method with carboxymethylcellulose and aluminium sulfate. 3³ factorial design was performed for three independent variables, namely, the particle size of the drug, the size of the microcapsules and the pH of the dissolution medium. The dissolution tests with the formulated microcapsules were carried out according to the United States Pharmacopeia XXII rotating basket method at pH 1.2, 5 and 7.5, which represent the pH of gastrointestinal fluids. Release data were examined kinetically and the ideal kinetic models were estimated and t _63.2 values obtained from RRSBW distribution were used in the factorial design experiment. The influence of the independent variables on the dissolution of nitrofurantoin microcapsules could be expressed as the pH of the dissolution medium > particle size of the microcapsule > particle size of nitrofurantoin. The other aim of this study was to evaluate microcapsule formulation in terms of the United States Pharmacopeia criteria with a minimum of experiments. Our findings suggest that dosage forms which comply with the pharmacopoeia criteria for dissolution can be prepared and selected by factorial design.