Bones and My Future?
I am just fascinated by skeletal structure, joints, bone tissue: individual bones, and how they all fit together. Human bones are especially fascinating, maybe because I can identify with the subject matter. I love studying x-ray images. I have a segment of a bison spine in the big freezer in the garage; it's been out there for over a year, and I still need to clean and sterilize it, but it's
there for when I find the time, and eventually it will be something cool to display on my desk. (I lobbied to gain custody of a humerus or femur as well, but they've been reserved for the dog.) The myriad times I've been in physical therapy, I pestered my therapists with questions about anatomy and joint structure, bone mineralization, cartilage, scar tissue, muscle attachments, ligaments, etc.
Bones are cool.
I have concluded that I will very likely continue my education; the biomedical field is one of two likely areas of study (the other being air quality and/or environmental policy). Should I go the biomedical route, I suspect I'll end up doing something bone-related. On the far engineering side of that field, there are narrower areas such as bone fracture mechanics, material properties and mineral composition of different types of bone, and orthopedic implants. Another area that I've started thinking about in the last two weeks is physical anthropology; there, I could specialize in anthropometry, forensic identification, musculoskeletal adaptations in certain groups of people (such as increased calcification around the knuckles of rock climbers), or something like that.
So, bones. Yep. They're fascinating ("cool"). (I'd really like to get a replica human femur or humerus to keep on my desk. Vertebrae are also nifty.)
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Labels: my future, ponderings, science
Round-up of the pet project
Here's my summary of design issues for the
plug-in prosthesis idea.
Really, this design concept isn't so far off. It's probably a long ways from bulk commercial production, because it's kind of an expensive prospect at this point, but the actual implementation is within our grasp.
The electromechanical functions of the prosthesis may be complicated, but this has all been done by robotics research groups focusing on control of biofidelic movement.
The interface linking the peripheral nerves to the prosthesis is a three-stage problem:
1. The "plug-in" interface on the prosthesis itself.
Comparatively speaking, this is trivial.
2. The direct tie-ins between the implanted cybernetic interface (ICI) and the nerves.
This is not so trivial. However, referring back to
previous entries including research on the
FINE (flat-interface nerve electrode), we can see that the groundwork for this stage is well underway.
3. The implantation and long-term maintenance of the ICI itself, the physical module that will interface mechanically with the body and the prosthesis.
This is probably the most difficult part of the entire design. I foresee three areas of primary concern:
A)
Mechanically, this unit has to hold up under not-insignificant loading; it has to be firmly anchored in the limb, and it has to transmit forces between the limb end and the prosthetic. Ideally, it will perform as a nearly-seamless mechanical interface with little to no maintenance requirements, because repairs on this level will likely require surgical intervention.
B) Electrically, the ICI needs to maintain good contacts with the prosthesis. Over time, various elements may require replacement; this shouldn't be too much of a hassle.
C) Biologically, the ICI should not provoke any kind of long-term inflammatory or immune response. Here, it is important to recognize that the direct neural interface will require a permanent disruption in the body's natural coverings (skin, underlying connective tissues). On the biological side of the interface, at some point the natural and the synthetic will meet. Some questions here involve the extent of skin coverage -- will the skin be continuous over the end of the limb, or will it end at a seam along the edge of the ICI? If the skin is continuous, will it cover most of the ICI surface (in which case irritation will be a concern where the skin touches the prosthesis), or will the ICI fit over it like a cap (in which case irritation is still a concern)?
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Labels: engineering, science
Zen for geeks
I used to write a lot of poetry. This was something I scribbled on paper a couple of years ago. I came across it the other day, and just reading it left me with a pleasantly relaxed mindset.
It's untitled, but I like to think of it as a kind of poetical zen (for geeks, and other people who think too much).
I could spend hours
right here,
lying among the flowers,
breathing in the air:
sheer, sunlit atmosphere.
Breathe deep --
the flowers love to share --
and worries lose hold
on the edge of sleep,
as if this fresh earth smell,
both new and old,
is some chemical debonder
of stress;
it soothes as it wanders,
permeating
and percolating
with feather-light caress,
until every care
diffuses through the shell
of my skin, to the air,
to be lost, finally,
inconsequently.
If I wait
a long, long time, maybe
it will permeate
all of me;
and I just might
sublimate
and float away,
my very DNA
taking flight
to come apart
sequentially,
the tiny atoms of my heart
mingling with the atmosphere
to be Breathed,
essentially,
through the very lungs of Earth,
my double-helix unwreathed
in a kind of rebirth;
and fade to black,
from whence I came,
lacking form to hold my name --
carbon to oxygen and back.
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Labels: imagine yourself here, literature, philosophy, ponderings
Ever wondered how MRI works?
Magnetic resonance imaging (MRI) is a powerful tool in medical diagnostics, yielding a true three-dimensional image of large tissue volumes. It works by producing a strong graded magnetic field along a specified spatial axis. Most biological tissues contain large concentrations of hydrogen atoms, usually in the form of water. The atomic nuclei of some of these hydrogen atoms align with the field. Then the tissue is bombarded with radio waves of a specific frequency, exciting these nuclei. This causes the nuclei to "flip" their polarity back and forth between their two aligned states; each "flip" is actually a specific excitation event and subsequent "relaxation," which causes an energy emission. These emissions are measured and used to produce an image of the hydrogen content of the tissue. Because the magnetic field gradient can be generated along various spatial axes, a series of images can be taken and compiled into a three-dimensional image.
Contrast-enhanced MRI involves introducing a contrast agent (usually a gadolinium compound) into the tissue's blood supply. These contrast agents appear very bright on MRI images. The contrast agent can be thought of as a probe of sorts, spreading throughout the cardiovascular system and diffusing into the extracellular space as permitted. This technique is especially useful in screening for or imaging cancers, many of which are highly vascular tissues, because the contrast agent will tend to accumulate in highly vascular areas.
Functional MRI (fMRI), which involves the rapid acquisition of a sequence of time-dependent images, can help differentiate cancers from benign lesions. This is because benign lesions generally have a more normal vascularity than malignant lesions, and therefore are usually seen to enhance more slowly on fMRI sequences.
For more in-depth reading:
How MRI WorksMRI - WikipediaThe Basics of MRI (on-line textbook)
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Labels: engineering, science
I am just fascinated by skeletal structure, joints, bone tissue: individual bones, and how they all fit together. Human bones are especially fascinating, maybe because I can identify with the subject matter. I love studying x-ray images. I have a segment of a bison spine in the big freezer in the garage; it's been out there for over a year, and I still need to clean and sterilize it, but it's there for when I find the time, and eventually it will be something cool to display on my desk. (I lobbied to gain custody of a humerus or femur as well, but they've been reserved for the dog.) The myriad times I've been in physical therapy, I pestered my therapists with questions about anatomy and joint structure, bone mineralization, cartilage, scar tissue, muscle attachments, ligaments, etc.
