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Cellular and Molecular Mechanics

Submitted by prleduc on

Cellular and Molecular Mechanics

I was invited by Dr. Zhigang Suo to write a short piece on “Cellular and Molecular Mechanics”. I am writing this informally to introduce this subject matter rather than talk in vernacular such as mechanotransduction, phosphorylation, etc. I have more formal papers if someone is interested in more detailed discussions on this subject area. This is a field in which I have been working for over a decade now and I find it more exciting every day. The question always is how does mechanics affect biological processes. This is a very interdisciplinary subject matter as mechanists, engineers, physicists, chemists, and biologists have been investigating this process from various perspectives. I am obviously not the first to study this process. For most of us, it is realized from an empirical perspective that mechanics matters to biology, but exactly how mechanics specifically alters biochemistry continues to be highly debated today. Mechanics of course matters in many physiological areas. Your blood flows, your heart pumps, your bone and muscle feel mechanics. Not only does the body experience mechanical stimulation, but it reacts biochemically to it. A wonderful example is when people go into space (NASA) for long periods of time. The bone in one’s body begins to resorb in a similar response mode to what one experiences in aging (osteoporosis). This is primarily due to just the change in the gravity (mechanics). Other diseases are related to these issues including the two biggest killers: heart disease and cancer. While biomechanics on this scale has been studied for awhile (Leonardo Da Vinci, who was interested in mechanics, also wrote one of the first texts on anatomy), the movement to the cellular and molecular scales has brought a tremendous amount of excitement. I consider the cell as one of the ultimate smart materials exhibiting these characteristics. The cell has evolved over millions of years and is designed better than almost any system that we can personally build. Just as the biological eye provides a beautiful template for optics based lenses, much can be learned about building technology (“nanotechnology” and “microtechnology”) through examining the behavior of cells and molecules.

A Fresh Look at a Beautiful Subject

Submitted by Zhigang Suo on

This is a review on Thermal Physics by Charles Kittle and Herbert Kroemer. I posted the review on Amazon on 2 December 2001.

This is by far THE BEST textbook on the subject. As many people say, thermodynamics is a subject that one has to learn at least three times. I can easily understand the very negative review from the undergraduate student at Berkely. The subject itself is hard, and simply is not for everyone, not for the first run at least. I say this from experience. I earned a Ph.D. degree over ten years ago, and took courses on thermodynamics at both undergraduate and graduate levels. I didn't understand the subject at all, and didn't find much use in my thesis work. However, something about the subject has kept me going back to it ever since. I now own about 40 books on the subject, and use the ideas almost daily in my research.

the FFT based algorithm to solve the continuum electrostatic field

Submitted by Yuye Tang on

In the paper[1], the continuum electrostatic simulation in the ion transport through membrane-spanning nanopores is realized by the implicit-solvent method. To solve the problem, the governing equation (Poisson equation for systems with heterogeneous permittivity) is expressed and the electric field is calculated in its reciprocal space by applying 3D-FFT[2]. The system is considered periodic, and a modified vacuum field outside is defined. The rectangular unit cell is discredited into grid points. By iteratively revise this modified vacuum field, the residual of the electric field at the grid points reach its minimum in the real space. After getting the predefined threshold, the iteration is terminated and the reaction potential is calculated. The potential at any point in the domain is interpolate by its eight surrounding grid points. The accuracy and convergence properties of this proposed algorithm are very well, with an overall speed comparable to a typical finite-difference solver.

The Fourth China-Japan-Korea Joint Symposium on Optimization of Structural and Mechanical Systems

Submitted by Anonymous (not verified) on

The Fourth China-Japan-Korea Joint Symposium on Optimization of Structural and Mechanical Systems will be held in Kunming, China, November 6–9, 2006.

http://sail.dlut.edu.cn/cjkosm4/Home/Index.htm

Recent advances of computer technology have given powerful practical tools to structural and mechanical designs. Optimal design is one of such area where various theories and methodologies are well developed. It is, however, lacking general interests among field designers and engineers. Innovative optimal design techniques and new applications are yet to be developed. Following the successful first CJK-OSM1 in Xian, China in 1999, second (CJK-OSM2) in Busan, Korea in 2002 and the third (CJK-OSM3) in Kanazawa, Japan in 2004, as agreed among participants in the symposium, the fourth CJK-OSM symposium will be held in Kunming, China during Nov. 6th -Nov. 9th, 2006. As before this will be a forum for exchange of recent research ideas and fostering new developments and new applications. Reflecting current interests from various fields, several new topics are included. The scope is, however, not limited to those listed.

Student Presentation Competition at USNCCM IX

Submitted by John E. Dolbow on

The 9th US National Congress on Computational Mechanics will feature a student presentation competition. This competition continues in the format pursued at the recent World Congress in Los Angeles. It is open to students who have an abstract accepted for presentation at the Congress.