Robust rigid registration of retinal angiograms through optimization

Retinal fundus photographs are employed as standard diagnostic tools in ophthalmology. Serial photographs of the flow of fluorescein and indocyanine green (ICG) dye are used to determine the areas of the retinal lesions. For objective measurements of features, the registration of the images is a necessity. In this paper, we employ optimization techniques for registration with the help of 2-parameter translational motion model of retinal angiograms, based on non-linear pre-processing (Wiener filtering and morphological gradient) and computation of the similarity criteria for the alignment of the two gradient images for any given rigid transformation. The optimization methods are effectively employed to minimize the similarity criterion.

The presence of noise, the variations in the background and the temporal variation of the fluorescence level pose serious problems in obtaining a robust registration of the retinal images. Moreover, local search strategies are not robust in the case of ICG angiograms, even if one uses a multiresolution approach.

The present work makes a systematic comparison of different optimization techniques, namely the minimization method derived from the optical flow formulation, the Nelder-Mead local search and the HCIAC ant colony metaheuristic, each optimizing a similarity criterion for the gradient images. The impact of the resolution and median filtering of gradient image is studied and the robustness of the approaches is tested through experimental studies, performed on macular fluorescein and ICG angiographies.

Our proposed optimization techniques have shown interesting results especially for high resolution difficult registration problems. Moreover, this approach seems promising for affine (6-parameter motion model) or elastical registrations.     

磁刺激用平面线圈结构的优化研究

文中建立了采用任意形状平面线圈磁刺激仪的RLC模型，给出了模型参数的计算方法。为了优化线圈，将磁刺激仪线圈的性能指标分为反映线圈输出性能的峰值磁能和反映线圈结构的几何变量。在磁刺激激活函数达到阈值条件下，调整平面螺旋线圈的结构并计算出依赖于线圈结构参数的输出性能值，从而，寻找最优的线圈几何参数。优化结果表明：线圈外半径是关键因素，给定阈值条件，选择合适的线圈外半径，可以大大降低线圈峰值磁能；另外，现在使用的圆环线圈并非最优，D形线圈优于圆环线圈。     

优化原理与小动脉血流量─管径关系

作者假设血液为符合幂定律的非牛顿流体，对小动脉血管系统进行了详细的优化分析。导出了血流量与管径立方成正比的结论以及壁面切变率与管径无关的推论。此结果既包含了前人对于牛顿血流的研究成果，又能克服后者的不足，而与近期的生理测定一致。     

Single dipole localization: Some numerical aspects and a practical rejection criterion for the fitted parameters

Summary There have been a number of attempts in the last years to localize the generators of brain electromagnetic activity, considering one current dipole as the source model. Single Dipole Localization (SDL) requires the selection of an optimization algorithm (OA). General aspects related with the selection, implementation and evaluation of some of the OA employed for SDL are discussed in this paper. Specifically the performance of two algorithms, those of Hooke-Jeeves and Levenberg-Marquardt, are tested by simulations. Suggestions for including restrictions to the dipole position and comments about some commonly used measures of the goodness of fit are given. Examples of erroneous implementations of these algorithms are also illustrated. A simple graphic rejection criterion, which can be easily used by inexperienced researchers, is introduced and tested in noisy and noise free simulations.The authors are grateful to Roberto D. Pascual Marqui for programming the Hooke-Jeeves algorithm.     

Optimization of a formulation for direct compression using a simplex lattice design

In this paper it is demonstrated how the optimum composition of a mixture for direct compression consisting of -lactose monohydrate, roller-dried -lactose and microcrystalline cellulose can be found using a systematic optimization technique. The experiments were chosen according to a simplex lattice design. The results of these experiments were used to fit a mathematical model, which then can predict the properties of all possible mixture compositions and enables a graphic representation of these properties in the form of contour plots. At a level of 4% the effect of three disintegrants (sodium starch glycolate, croscarmellose sodium and crospovidone) on the properties of the tablets compressed from these filler-binders, was evaluated by superimposing the contour plots of the different tablet responses. It was found that all the disintegrants used were effective in this combination of filler-binders. In order to evaluate drug dissolution rate an extra experiment with crospovidone as the disintegrant was performed, in which oxazepam was used as a test drug.     

Iterative reconstruction algorithms

In this paper a survey of recent results on iterative reconstruction algorithms is given. These results, many of which have not yet appeared elsewhere, are applicable to a very general formulation of the reconstruction problem based on the series expansion approach. A set of optimization criteria and a number of iterative reconstruction algorithms are stated, together with theorems on the convergence of the algorithms to optimum images. The efficacy of the algorithms is compared to that of the convolution method. In particular, the falseness of the claim that ART and the backprojection method are the same is demonstrated.     

南昌链霉菌生物合成梅岭霉素种子制备优化

以参数相关理论为指导,优化南昌链霉菌生物合成梅岭霉素种子制备工艺。结果表明,培养20～35h后,pH7.30～7.50,总糖<0.35%,pmv>10%,溶磷<100μg/ml,菌丝分化启动有利于提高梅岭霉素的发酵效价。     

采用高架十字迷宫实验优选抗焦虑复方中药制剂中当归和川芎的制备工艺

目的:通过小鼠高架十字迷宫药效学实验对抗焦虑复方中药制剂中当归和川芎的两种制备工艺(煎煮法和双提法)进行优选。方法:健康雄性昆明种小鼠,随机分为空白对照组、阳性药地西泮组、抗焦虑中药(归芎煎煮法)高、中、低剂量组、抗焦虑中药(归芎双提法)高、中、低剂量组。空白对照组给予生理盐水及其余各组给药10d,第10d进行高架十字迷宫药效学测试,对开臂时间百分率和开臂次数百分率进行统计。结果:与空白对照组比较,地西泮组和归芎双提法高、中剂量组的开臂时间百分率和开臂次数百分率均有显著性差异(P<0.05),而归芎煎煮法各剂量组未见统计学意义。结论:采用双提法提取当归和川芎制备的抗焦虑中药的抗焦虑药效优于采用煎煮法的制剂。     

优化质量管理在口腔科消毒供应中心的应用

目的 探讨优化质量管理在口腔科消毒供应中心的应用及实施效果.方法 将已经使用过的口腔复用诊疗器械进行椅旁预处理后,集中回收到消毒供应中心,对器械进行程序化的分类、清洗消毒、检查保养、包装、灭菌,加强对诊疗器械清洗质量以及灭菌后湿包率的管理力度.结果 实施质量管理后清洗合格率比实施前提高(90.63％比84.00％,P=O.000 2),无菌物品的湿包发生概率明显降低(3.13％比5.56％,P=0.000 7).结论 优化质量管理能够提升口腔科复用器械的清洗质量和灭菌质量.     

优化我院门诊药房工作流程的研究

目的:探索优化我院门诊药房工作流程。方法:通过问卷调查、仿真数据处理、咨询专业顾问公司等方法找出目前我院门诊药房工作流程中存在的主要问题,并分析制定优化流程的具体措施。结果:我院门诊药房现有流程的主要问题是患者取药等候时间过长和药房工作效率低。而导致上述问题的原因为预调配、手写处方、药房的布局不合理、屏幕提示及药师叫号、药房空间不足和硬件故障等。通过数据分析,优化流程的主要方向是简化流程,取消预调配;建立医师工作站,实行电子处方;合并中、西药房;更新硬件配置;增加指引标识;优化空间布局,调整药品摆放;调整各岗位药师比例。结论:通过优化流程,可提高药师的工作效率,缩短患者取药等候时间,提高患者、医师、药师三方的满意度。