基于稀疏分解法的单次诱发电位提取

迭代加权稀疏分解法是按照白噪声在小波的多分辨结构中的二尺度关系来确定求最小l1模优化问题时的加权系数,并通过一个迭代过程来逐步消除强噪声的影响。通过对视觉诱发电位的单次提取的研究说明了这种方法具有良好的单次提取效果,其实验结果支持单次提取的视觉诱发电位是不相同的观点。     

熵正则化磁共振成像理论及迭代算法

实际的磁共振成像系统 ,通常仅能收集有限的频谱数据 ,傅立叶变换法重建的图像存在Gibbs伪影 ,且分辨率有限。我们提出的熵正则化磁共振成像方法是考虑与原始频谱数据一致性的条件下 ,熵极大化而获得的结果。重建的图像具有无限的分辨率 ,降低Gibbs伪影及信号中的噪声。本算法的稳定性优于模型最大熵法[12 ] 。对截断及噪声的频谱数据的成像结果证实了我们方法的有效性     

Codon optimization of the human papillomavirus 11 (HPV 11) L1 gene leads to increased gene expression and formation of virus-like particles in mammalian epithelial cells

The 505 amino acid L1 protein of the human papillomavirus type 11 (HPV 11) is the major capsid polypeptide that has been shown to self-assemble into virus-like particles (VLPs) in vivo and in vitro. While L1 is essential for viral infection, expression studies in mammalian cells have been hampered by different codon preference between the virus and its host. To optimize L1 gene expression in mammalian cells, we converted wild-type HPV 11 L1 (11 L1wt) codons to those more common in human genes. The modified HPV 11 L1 gene (11 L1h) generated protein levels that were at least 100-fold higher than those of wild-type HPV 11 L1, while no obvious differences were seen in the level of mRNA. HPV 11 L1 protein was detected in mammalian epithelial and fibroblast cells, by immunoblotting and indirect immunofluorescence (IIF) techniques. Unlike the situation in situ, IIF revealed the presence of L1 mainly at perinuclear sites. Virus-like particles assembled intranuclearly only to a low extent, as indicated by transmission electron microscopy. DNA vaccination using the HPV 11 L1h gene yielded a drastic increase in L1-specific antibody production in mice as compared to immunization with the wild-type gene.     

A method for shape optimization of a hip prosthesis to maximize the fatigue life of the cement

The long term success of total joint replacement can be limited by fatigue failure of the acrylic cement and the resulting disruption of the bone-cement interface. The incidence of such problems may be diminished by reduction of the fatigue notch factor in the cement, so that stress concentrations are avoided and the fatigue crack initiation time maximized. This study describes a method for numerical shape optimization whereby the finite element method is used to determine an optimal shape for the femoral stem of a hip prosthesis in order to minimize the fatigue notch factor in the cement layer and at interfaces with the bone and stem.

A two-dimensional model of the proximal end of a femur fitted with a total hip prosthesis was used which was equivalent to a simplified three-dimensional axisymmetric model. Software was developed to calculate the fatigue notch factor in the cement along the cement/stem and cement/bone interfaces and in the proximal bone. The fatigue notch factor in the cement at the cement/stem interface was then minimized using the ANSYS finite element program while constraining the fatigue notch factor at the cement/bone interface at or below its initial level and maintaining levels of stress in the proximal bone to prevent stress shielding. The results were compared with those from other optimization studies.     

Decision and forecast horizons in a stochastic environment: A survey

This paper constructs a unified framework to survey most of the work done to date on decision

1 decision horizon replaces the term planning horizon used in the literature in the context of this paper. This is done because of an alternate and more popular use of the term planning horizon as simply the given length of the horizon in a finite horizon problem.

and forecast horizons in a stochastic environment. The paper is divided into sections by type of model. For each model type, the issues of existence of these horizons and of derivation of sufficient conditions for their determination are studied. Appropriate examples are presented.     

Using Metamodeling to Identify the Optimal Strategy for Colorectal Cancer Screening

ObjectivesMetamodeling can address computational challenges within decision-analytic modeling studies evaluating many strategies. This article illustrates the value of metamodeling for evaluating colorectal cancer screening strategies while accounting for colonoscopy capacity constraints.MethodsIn a traditional approach, the best screening strategy was identified from a limited subset of strategies evaluated with the validated Adenoma and Serrated pathway to Colorectal CAncer model. In a metamodeling approach, metamodels were fitted to this limited subset to evaluate all potentially plausible strategies and determine the best overall screening strategy. Approaches were compared based on the best screening strategy in life-years gained compared with no screening. Metamodel runtime and accuracy was assessed.ResultsThe metamodeling approach evaluated >40 000 strategies in <1 minute with high accuracy after 1 adaptive sampling step (mean absolute error: 0.0002 life-years) using 300 samples in total (generation time: 8 days). Findings indicated that health outcomes could be improved without requiring additional colonoscopy capacity. Obtaining similar insights using the traditional approach could require at least 1000 samples (generation time: 28 days). Suggested benefits from screening at ages <40 years require adequate validation of the underlying Adenoma and Serrated pathway to Colorectal CAncer model before making policy recommendations.ConclusionsMetamodeling allows rapid assessment of a vast set of strategies, which may lead to identification of more favorable strategies compared to a traditional approach. Nevertheless, metamodel validation and identifying extrapolation beyond the support of the original decision-analytic model are critical to the interpretation of results. The screening strategies identified with metamodeling support ongoing discussions on decreasing the starting age of colorectal cancer screening.     

化工过程在线模拟和优化的软件框架

首先讨论了在线优化和企业自动化水平的关系,接着描述了过程模型的开发和实现范例,并归纳了一个在线优化软件系统的功能需求,进而描述了一个面向程的模拟优化系统的主要组成部分,最后讨论了在线优化应用的结构以及和控制策略的关系。     

预测加氢裂化过程的产率

以缓和加氢裂化数据为基础,对于两种典型的加氢裂化动力学模型－－Stangeland模型和改进MHC模型,使用Shor最优化法进行了参数的拟合,比较了这两种动力学模型的结果、算法、复杂度以及预测能力。结果表明,改进MHC模型是一种更为合理的动力学模型,该模型也可用于实际加氢过程。     

Analysis of acute-phase toxicities of intensity-modulated proton therapy using a model-based approach in pharyngeal cancer patients

Pharyngeal cancer patients treated with intensity-modulated proton therapy (IMPT) using a model-based approach were retrospectively reviewed, and acute toxicities were analyzed. From June 2016 to March 2019, 15 pharyngeal (7 naso-, 5 oro- and 3 hypo-pharyngeal) cancer patients received IMPT with robust optimization. Simulation plans for IMPT and intensity-modulated X-ray therapy (IMXT) were generated before treatment. We also reviewed 127 pharyngeal cancer patients with IMXT in the same treatment period. In the simulation planning comparison, all of the normal-tissue complication probability values for dysphagia, dysgeusia, tube-feeding dependence and xerostomia were lower for IMPT than for IMXT in the 15 patients. After completing IMPT, 13 patients completed the evaluation, and 12 of these patients had a complete response. The proportions of patients who experienced grade 2 or worse acute toxicities in the IMPT and IMXT cohorts were 21.4 and 56.5% for dysphagia (P < 0.05), 46.7 and 76.3% for dysgeusia (P < 0.05), 73.3 and 62.8% for xerostomia (P = 0.43), 73.3 and 90.6% for mucositis (P = 0.08) and 66.7 and 76.4% for dermatitis (P = 0.42), respectively. Multivariate analysis revealed that IMPT was independently associated with a lower rate of grade 2 or worse dysphagia and dysgeusia. After propensity score matching, 12 pairs of IMPT and IMXT patients were selected. Dysphagia was also statistically lower in IMPT than in IMXT (P < 0.05). IMPT using a model-based approach may have clinical benefits for acute dysphagia.     

基于精益六西格玛管理的门诊服务流程优化实践

目的探索精益六西格玛管理在综合医院门诊服务流程优化中的效果,提升门诊服务,改善患者就医体验。方法运用精益六西格玛管理体系5个阶段,选取2019年5—12月168万人次门诊患者为对照组、2020年1—8月120万人次门诊患者为观察组。对照组采用常规门诊管理,观察组采用精益六西格玛管理。比较两组门诊患者就诊时间、等候时间、取药时间、满意度。结果观察组门诊患者就诊时间、等候时间、取药时间均明显小于对照组,患者满意度高于对照组,差异有统计学意义(P<0.05)。结论基于精益六西格玛管理,门诊服务流程取得了较好的改进效果,不断优化门诊资源配置,患者满意度提高,最终得出一套适用于综合医院推广和借鉴的门诊服务优化流程。