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Modulated-Power Implantable Neuromodulation Devices and Their Impact on Surrounding Tissue Temperatures

Journal of Biomedical Science and Engineering 2016年第12期9卷 545-562页

作者： john R. stark Sergio R. Romero john M. Gorman john P. Abraham Ephraim M. Sparrow Department of Mechanical Engineering The University of Kansas Lawrence KS USA School of Engineering University of St. Thomas St. Paul MN USA Department of Mechanical Engineering University of Minnesota Minneapolis MN USA

This project was intended to determine whether the preprogrammed time-varying recharge protocol for a battery incased in a neuromodulation implant can give rise to tissue temperatures that surpass a safe level or are otherwise benign. The study included the development of a highly accurate model of all the thermal processes that are activated by the recharging of the battery contained within the neuromodulation implant. The model was implemented by numerical simulations performed for several realistic operating conditions. The computed spatial and temporal tissue temperature distributions were employed to estimate possible tissue damage by making use of two independent methodologies. Independent calorimeter-based experiments were performed to provide validation for the calculated rates of heat generation in the coils of the implant. Spatial and temporal tissue temperature distributions extracted from the numerical simulations revealed the thermal effects associated with several realistic operating protocols. None of the operating protocols gave rise to temperatures above 42℃. Numerical values of thermal tissue damage metrics were determined and compared with accepted values which correspond to the absence and the presence of tissue damage. The experimentally determined rate of heat generation in the implant coils validated that from electrical measurements to within 2%. Both the tissue temperature results and the thermal damage metrics found no evidence of tissue injury when time-varying preprogrammed protocols are used in the recharging of neuromodulation implant-encased batteries.

关键词： Biological Heating Neurostimulation Neuromodulation Implant Recharge Thermal Injury Modulated-Power Implant

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Controlling the rate of penetration of a therapeutic drug into the wall of an artery by means of a pressurized balloon

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Journal of Biomedical Science and Engineering 2013年第5期6卷 527-532页

作者： john R. stark john M. Gorman Ephraim M. Sparrow john P. Abraham Rob E. Kohler Cardiovascular Systems Inc. St. Paul USA Department of Mechanical Engineering University of Minnesota Minneapolis USA School of Engineering University of St. Thomas St. Paul USA

The focus of this paper is to propose, model, and characterize a means of accelerating the rate of delivery of therapeutic drugs to human tissues. The investigated means is a pressurized, permeable-walled balloon filled with a homogeneous mixture of the drug and the carrier fluid. The fluid mixture, driven by pressure, traverses the thickness of the balloon wall through laser-drilled pores. The number and deployment of the pores can be controlled to a high degree of precision. As a consequence, the wall of the balloon can be regarded as a homogeneous porous medium, and the traversing fluid flow can be analyzed by means of porous media models. When the balloon is in intimate contact with the surface of a tissue bed, the therapeutic fluid flows in series as it passes through the balloon wall and penetrates the tissue. The flow rate can be controlled by proper selection of the balloon permeability, the viscosity of the flowing medium, and the pressure internal to the balloon. The delivered concentration of the drug was predicted by coupling the present balloon-focused theory with a previously developed tissue-bed model that includes both diffusion and advection processes. The tribologic interaction of the pressurized balloon with an artery wall was investigated experimentally to assess the possible formation of aneurysms.

关键词： Heart Disease Plaque Treatment Paclitaxel Drug Delivery

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Impacts of waveforms on the fluid flow, wall shear stress, and flow distribution in cerebral aneurysms and the development of a universal reduced pressure

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Journal of Biomedical Science and Engineering 2014年第1期7卷 7-14页

作者： Noel M. Naughton Brian D. Plourde john R. stark Simona Hodis john P. Abraham Department of Radiology Mayo Clinic Rochester USA School of Engineering University of St. Thomas St. Paul USA

The hydrodynamics of aneurysm blood flow is thought to be a critical factor in the evolution and potential rupture of blood vessel walls. The ability to predict which aneurysms may grow or rupture has eluded researchers and practicing clinicians. On the other hand, it is expected that local flow patterns, pressures, and wall shear stress play a role in the aneurysm life. In this study, the impact of waveform on these parameters was studied. A baseline waveform, taken from a patient, was applied to an aneurysm geometry. Then the waveform was modified by increasing and decreasing both the flowrates and the cardiac rate. In total, seven cases were investigated. It was found that there were remarkable similarities in the patterns of flow and wall stresses for the cases. These similarities existed throughout the cardiac cycle. It was also found that there was a reduced pressure variable that provides a universal relationship that characterizes all of the cases. It was seen that the maximum wall shear occurs at the neck of the aneurysm and scales with the peak systolic velocity. Finally, it is shown that the flow distribution to the multiple outlets does not appreciably depend on the details of the inlet waveform. All cases had a flow distribution that was within 2%.

关键词： Aneurysm Hemodynamics Blood Flow Computational Fluid Dynamics

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Influence of Supporting Tissue on the Deformation and Compliance of Healthy and Diseased Arteries

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Journal of Biomedical Science and Engineering 2015年第8期8卷 490-499页

作者： Biyuan Sun Lauren J. Vallez Brian D. Plourde john P. Abraham john R. stark School of Engineering University of St. Thomas St. Paul USA The University of Kansas Department of Mechanical Engineering Lawrence USA

Hemodynamics and the interaction between the components of the cardiovascular system are complex and involve a structural/fluid flow interaction. During the cardiac cycle, changes to vascular pressure induce a compliant response in the vessels as they cyclically stretch and relax. The compliance influences the fluid flow throughout the system. The interaction is influenced by the disease state of the artery, and in particular, a plaque layer can reduce the compliance. In order to properly quantify the fluid-structural response, it is essential to consider whether the tissue surrounding the artery provides a support to the vessel wall. Here, a series of calculations are provided to determine what role the supporting tissue plays in the vessel wall and how much tissue must be included to properly carry out future fluid-structure calculations. Additionally, we calculate the sensitivity of the compliance to material properties such as the Young’s modulus or to the transmural pressure difference.

关键词： Fluid-Structural Interaction Blood Flow Compliant Vessels Finite Element Analysis

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表面处理胶粉含量高的胎面胶料

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橡胶参考资料 1992年第3期22卷 18-24,13页

作者： john stark 张金梅周琳

前言轮胎制造是大量使用合成橡胶和天然橡胶胶料的缩影,而胎面胶的制造进一步集中体现了轮胎工业配合技术的重要作用。过去认为胎面胶料中能掺用小百分比量的废硫化橡胶粉,其结果只是对耐磨性稍有降低;然而。

关键词：轮胎胶料胶粉表面处理

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调解的现状回顾与理论发展

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北京仲裁 2010年第2期 108-138页

作者： James A.Wall john B.stark Rhetta L.Standife 颜杰雄美国密苏里大学哥伦比亚分校管理系武汉大学国际法研究所

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POSTERIOR CHAMBER INTRAOCULAR LENS IMPLANTATION IN THE ABSENCE OF POSTERIOR CAPSULAR SUPPORT

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Eye Science 1989年第Z1期14卷 19-23页

作者： Walter J.stark Gerri Goodman Daniel Goodman john Gottsch Wilmer Ophthalmological Institute johns Hopkins University School of Medicine Baltimore Maryland U. S. A

Because of the high incidence and great variety of complications associated with anterior chamber intraocular lenses, we have developed a technique for the implantation of a posterior chamber intraocular lens in the absence of posterior capsular suport. The posterion chamber ■ is placed in the ciliary sulcus hy suturing the superior haptic to the iris and the inferior haptic to the sclera at the ciliary sulcus. We have used this technique successfully in both compheated extranapsular surgery and se-

关键词： intraocular capsular inferior implantation chamber suture placed incidence keratoplasty absence

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A CONSERVATIVE VIEW OF RADIAL KERATOTOMY

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眼科学报 1991年第3期7卷 130-139页

作者： Steven Olkowski Walter J.stark john D.Gottsch Gerri Goodman Daniel Goodman A.E.Maumenee Ivan Esente The Wilmer Ophthalmological Institute The Johns Hopkins University School of MedicineBaltimoreMaryland 21205U.S.A.

It has been known for almost a century that radial keratotomy(RK)will flatten the cornea and reduce *** the introduction of radial keratotomy(RK)in the United States by Bores in 1978,there have been many published studies documenting the effects of this *** *** radial keratotomy today are not only quantitative but also qualitative in *** know this technique can flatten the cornea,but how reliably can the results be predicted?

关键词： RK A CONSERVATIVE VIEW OF RADIAL KERATOTOMY

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VISUAL DISABILITIES RELATED TO INTRAOCULAR LENS DESIGN

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Eye Science 1990年第Z1期15卷 36-39页

作者： Gerri Goodman Walter J.stark john D.Gottsch Daniel Goodman Steven Olkowski A.E.Maumenee Ivan Escape Wilmer Ophthalmological Institute johns Hopkins University School of Medccine Baltimore Maryland U. S. A.

Intraoeular. lens implantation after cataract extraction has become a common practice in the United States. However, unwanted optical images can correet an otherwise successful surgery into one that causes patient dissatisfaction. Refinements in manufacturing design and finishing have greatly improved the quality of present day intraocular lenses, but there is continued interest in simulating the optics of the human crystalline *** will discuss the optical requirements of intraocular lenses and how these are influenced by optic design and dimension, and spectral transmission characteristics.

关键词： intraocular cataract otherwise implantation crystalline optic VISUAL continued finishing aberration

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Clinical Forensic Medicine 2nd ed. 2005

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丛书名： Forensic Science and Medicine

2005年

作者： Margaret M. stark

ISBN: (数字)9781592599134

ISBN: (纸本)9781588293688

This revised edition has been completely updated and expanded to address the latest developments and professional concerns in forensic medicine. There are new chapters on the medical aspects of police restraint and new material on the potential of police exposure to infection, the role of alcohol and drugs in vehicular accidents, and forensic sampling in sexual assault examinations. The chapters on fundamental principles, nonaccidental injury in children, and the care of detainees are all fully revised, as are the appendices (now containing a list of useful websites)

关键词： Forensic Medicine

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