Signal Processing, Mathematical Modeling and Final Remarks

The final three chapters provide an introductory overview of signal processing and mathematical modeling with final remarks about the future of biomedical engineering.  I enjoyed chapter six’s discussion on signal discretization i.e. how continuous analog signals can be converted into discrete digital signals.  For example, it’s possible to retain the integrity of an analog signal after discretization if the components of the sampled signal do not exceed the folding frequency.  This may seem a little abstract although Valentinuzzi provides a simple graph and gives a real-life example of what it looks like when a signal’s frequency components are reconstructed beyond the folding frequency.  A signal that is improperly converted is prone to distortion or aliasing−Valentinuzzi explains that in old western movies, you see aliasing when a wagon trying to get away from a bunch of bad guys appears to be moving backwards.  This occurs because the “movie’s frame rate undersamples the rotation frequency of the wheel”.           

Chapter seven likewise follows with an interesting discussion, it talks about the need for mathematical models to improve the quantification of physiological processes.  Valintinuzzi takes a reductionist’s approach to describe linear versus non-linear models.  He explains that a system is linear when an output signal completely reproduces the input signal; otherwise, the system is non-linear if the output signal is distorted.  A system is considered statistical when an output signal emerges with a certain probability following an input.  Statistical systems may be either linear or non-linear however they are not deterministic.  You have an oscillatory system when, as its name suggests, an input produces an output that oscillates with time.  This system is non-linear although for simplicity it may be treated as linear.  Oscillatory systems are deterministic and ubiquitous throughout biology and physiology−periodicity is seen in the heart, myelinated nerve fibers, DNA structure, bone formation etc.  Valintinuzzi reminds the reader that the descriptions above are oversimplified although oversimplifications are necessary for introductory textbooks.         

The last chapter of the book provides insight about the future of biomedical engineering.  This emerging field has very exciting prospects for innovations in tissue engineering, cell engineering, artificial implants, biomaterials and nanotechnology.  A discussion on biomedical engineering would not be complete without talking about ethical concerns.  Towards the end of the final chapter, Valintinuzzi shares that he is from and currently lives in Argentina, a socially and economically impoverished country.  Valentinuzzi talks about while traveling in Argentina, he sometimes takes a few moments to acknowledge the children at Infiernillo Elementary School and inquire about their future:

I admire the generous courage of their almost unsupported teachers. Certainly, if any of those children were to require, say, a cardiac pacemaker (a biomedical engineering product we are proud of), even the cheapest model would not be affordable for his/her family.  How many children like them are there all over the world?

Valentinuzzi expresses admiration for teachers and leaves us with a tough ethical question to grapple with.  My grandpa Holmes was also a teacher and the reason why I became a teacher.  He suffered from cancer and eventually fell victim to this horrible disease.  My grandmother and uncle also died from cancer and my mom is currently a breast cancer survivor.  They are now the reason I am inspired to continue my education in Biomedical Engineering.  I am particularly interested in targeted therapy research and cellular engineering for development of innovative cancer treatments.  Dr. Brinker’s current research at the University of New Mexico on nanocarriers to specific binding sites has tremendous potential for the former.  Chemotherapy often has debilitating side-effects, yet remains to be one of the most commonly administered treatments for cancer.  The use of transport molecules to mitigate the side-effects of chemotherapy drugs is thus a very important application for cancer treatment. 

Whole genome sequencing and drug development applications likewise present very exciting prospects for cancer treatment.  The driving force behind cancer cells is their ability to mutate and thus resist treatment−so I am especially interested in working with Dr. Melancon and his team at the University of New Mexico in collaboration with Dr. Jeremy Edwards, because of their integrative approach to bacterial genome sequencing and the discovery of new natural products (NPs) for cancer drug development.   

This concludes my seven-part blog series on teaching, learning and biomedical engineering.  I sincerely hope these blogs were interesting or at the very least useful in helping you better understand this exciting new field!  If so, I would be more than happy to continue posting literature reviews on current peer-reviewed research.  It was a pleasure doing these blogs and if anybody has any questions, feel free to shoot an e-mail!

-Derek