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Biomedical Engineering and Bioengineering Commons

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Full-Text Articles in Biomedical Engineering and Bioengineering

Genetic Programming For Multitimescale Modeling, Kumara Sastry, Duane D. Johnson, David E. Goldberg, Pascal Bellon Aug 2005

Genetic Programming For Multitimescale Modeling, Kumara Sastry, Duane D. Johnson, David E. Goldberg, Pascal Bellon

Duane D. Johnson

A bottleneck for multitimescale thermally activated dynamics is the computation of the potential energy surface. We explore the use of genetic programming (GP) to symbolically regress a mapping of the saddle-point barriers from only a few calculated points via molecular dynamics, thereby avoiding explicit calculation of all barriers. The GP-regressed barrier function enables use of kinetic Monte Carlo to simulate real-time kinetics (seconds to hours) based upon realistic atomic interactions. To illustrate the concept, we apply a GP regression to vacancy-assisted migration on a surface of a concentrated binary alloy (from both quantum and empirical potentials) and predict the diffusion ...


A Numerical Method For Obtaining An Optimal Temperature Distribution In A 3d Triple-Layered Cylindrical Skin Structure, Le Zhang Apr 2005

A Numerical Method For Obtaining An Optimal Temperature Distribution In A 3d Triple-Layered Cylindrical Skin Structure, Le Zhang

Doctoral Dissertations

In recent years, it has been interesting to research hyperthermia combined with radiation and cytotoxic drugs to enhance the killing of tumors. The crucial problem is that when heating the tumor tissues, one needs to keep the surrounding normal tissue below a temperature that will produce harm. Thus, it is important to obtain the temperature field of the entire treatment region. The objective of this dissertation is to develop a numerical model for obtaining an optimal temperature distribution in a 3D triple-layered cylindrical skin structure. To this end, we pre-specify the temperatures to be obtained at the center and perimeter ...


Room-Temperature Atmospheric Pressure Plasma For Biomedical Applications, Mounir Laroussi, Xinpei Lu Jan 2005

Room-Temperature Atmospheric Pressure Plasma For Biomedical Applications, Mounir Laroussi, Xinpei Lu

Electrical & Computer Engineering Faculty Publications

As low-temperature non-equilibrium plasmas come to play an increasing role in biomedical applications, reliable and user-friendly sources need to be developed. These plasma sources have to meet stringent requirements such as low temperature (at or near room temperature), no risk of arcing, operation at atmospheric pressure, preferably hand-held operation, low concentration of ozone generation, etc. In this letter, we present a device that meets exactly such requirements. This device is capable of generating a cold plasma plume several centimeters in length. It exhibits low power requirements as shown by its current-voltage characteristics. Using helium as a carrier gas, very little ...


Continuous-Time Block-Oriented Adaptive On-Line Modeling For Time Varying Systems, Derrick K. Rollins Sr., Stephanie Loveland Jan 2005

Continuous-Time Block-Oriented Adaptive On-Line Modeling For Time Varying Systems, Derrick K. Rollins Sr., Stephanie Loveland

Chemical and Biological Engineering Conference Presentations and Proceedings

The development and maintenance of accurate predictive models for dynamic systems are highly challenged by system complexity, limited information (i.e., data), changing cross and time correlation structures and changing model parameters. Thus, for a model or modeling method to achieve long term success in implementation into a real system, it must be phenomenologically sound and adaptive, as well as being capable of immediate update from recently obtained process data (i.e., plant data). A model is phenomenologically sound when its structure accurately captures physical input and output relationships, and the stochastic behavior of process and measurement noise. On-line adaptive ...


Nanoscale Morphology Of Polyanhydride Copolymers, Matthew J. Kipper, Sheng-Shu Hou, Soenke Seifert, Papannan Thiyagarajan, Klaus Schmidt-Rohr, Balaji Narasimhan Jan 2005

Nanoscale Morphology Of Polyanhydride Copolymers, Matthew J. Kipper, Sheng-Shu Hou, Soenke Seifert, Papannan Thiyagarajan, Klaus Schmidt-Rohr, Balaji Narasimhan

Chemical and Biological Engineering Publications

The microphase separation in polyanhydride random copolymers composed of 1,6-bis(p-carboxyphenoxy)hexane and sebacic acid is described. Though the copolymers are random, the monomers are sufficiently long and the segment-segment interaction parameter is sufficiently high to promote microphase separation when the copolymer is rich in one component. Solid-state NMR spin diffusion experiments and synchrotron small-angle X-ray scattering are used to discern the length scales of the microphase separation. Both techniques reveal a nanostructure with domain sizes less than 25 Ã…. This nanostructure is compared to approximate calculations of chain dimensions based on a random coil model and discussed in ...


Construction Of A Tethered Poly(Ethylene Glycol) Surface Gradient For Studies Of Cell Adhesion Kinetics, K. Mougin, A. S. Ham, M. B. Lawrence, E. J. Fernandez, Andrew C. Hillier Jan 2005

Construction Of A Tethered Poly(Ethylene Glycol) Surface Gradient For Studies Of Cell Adhesion Kinetics, K. Mougin, A. S. Ham, M. B. Lawrence, E. J. Fernandez, Andrew C. Hillier

Chemical and Biological Engineering Publications

Surface gradients can be used to perform a wide range of functions and represent a novel experimental platform for combinatorial discovery and analysis. In this work, a gradient in the coverage of a surface-immobilized poly(ethylene glycol) (PEG) layer is constructed to interrogate cell adhesion on a solid surface. Variation of surface coverage is achieved by controlled transport of a reactive PEG precursor from a point source through a hydrated gel. Immobilization of PEG is achieved by covalent attachment of the PEG molecule via direct coupling chemistry to a cystamine self-assembled monolayer on gold. This represents a simple method for ...