My new favorite design concept
This is something I've been thinking about for a while. The basic concept is for a prosthesis that connects ("plugs in") to a cybernetic interface that's implanted on the stump end of an amputated limb. The idea started coming together in my head over a year ago. Privately I've been referring to it as the "plug-in prosthesis." Technologically and medically, it is rather complex, and it's also a very expensive prospect by the standards of today's consumer industry. However, it's not outside the realm of feasibility.
Originally, I started thinking about the more general design problem of a lower-limb prosthesis. The idea which I explored was basically to model the missing biological structures with mechanical components. The primary concern here is that the prosthetic limb mimics natural motion; this is potentially a real can of worms. The "natural motion" of the lower leg includes locomotion (walking, running, and everything in between, for which there are different requirements) as well as balance (the whole issue of lateral control and stability, and the role of our toes). The stability and motion of the ankle are also an important factor when you consider how often we set foot on uneven surfaces. Shock absorption in any dynamic motion (running, walking, jumping) is another important consideration. Another issue is the emotional value of a prosthesis that looks and feels natural. The prosthesis can easily be padded so as to mimic the shape of a natural human leg; however, if we really want to go for the pie in the sky, why not construct some sort of moving musculature?
Theoretically, we can design the prosthesis to include a synthetic model of every bone, tendon, ligament, and muscle found in the leg and foot. Practically, this rapidly complicates matters; how can we control all of these muscles?
One possibility, I thought, would be to implant a cybernetic interface into the amputated surface. This interface would plug into the prosthesis, providing a hard-wired connection that would transmit impulses from and to the existing nerve endings. The patient could have complete control of the prosthesis, as well as a good deal of sensation (depending on just how overboard we wanted to go in planting electromechanical sensory receptors in the prosthesis).
There are plenty of issues involved, and they span a lot of disciplines including physiology, biomechanics, biomaterials, robotics, and neurophysiology. I'm not an expert in any of these fields, but I know a little about all of them, and I'm a good researcher (so my research advisor tells me). As I work through the various aspects of the design, I'll try not to do too much hand-waving, because I'm really interested in how this concept could be implemented on a practical level.
Stay tuned. You always wanted to see the engineering design process in action, didn't you?
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Labels: engineering, science
Salary Theorem: The less you know, the more you make
I don't remember where I found this, but it makes perfect sense. Proof:
Given:
(1) Knowledge is Power.
(2) Time is Money.
(3) Power = Work / Time (as every engineer knows).
Let's do the math. We can combine (1), (2), and (3) as follows:
Knowledge = Power = Work / Time = Work / (Money). Therefore,
(4) Knowledge = Work / Money.
Solving (4) for Money, we get
(5) Money = Work / Knowledge.
Thus, as Knowledge approaches zero, Money approaches infinity, regardless of Work.
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Labels: engineering, everyday, philosophy, science
Supplements for treating joint pain
For those of you who have expressed interest in the effectiveness of glucosamine and chondroitin sulfate supplements in treating joint pain and/or inflammation,
here's what I've discovered.
Glucosamine and chondroitin/chondroitin sulfate are commonly thought to effectively treat osteoarthritis. Even if these treatments are only mildly effective, in many cases they may be a more desirable treatment option than non-steroidal anti-inflammatory drugs (NSAIDs) due to the adverse side-effects associated with the latter.
McAlindon et al. presented a review of previous studies on the effectiveness of glucosamine and chondroitin in treating osteoarthritis symptoms. They found that in general, the studies showed that glucosamine and chondroitin "demonstrate moderate to large treatment effects on symptoms." However, the authors found the methodology of most of these studies to be less than optimal, and stated their belief that these findings of effectiveness may have been exaggerated as a result.
Clegg et al. reported on one recent study, the Glucosamine/chondroitin Arthritis Intervention Trial (GAIT). In general, the response rates for glucosamine and/or chondroitin sulfate (alone or in combination) were not significantly higher than those for placebo; however, the response rates for glucosamine and chondroitin sulfate in combination were significantly greater in patients with moderate-to-severe joint pain (this was a relatively small group). Also, treatment with chondroitin sulfate correlated to a significant decrease in joint swelling and/or effusion. The authors remarked upon the high response rate (60.1%) to placebo and also upon the relatively minor symptoms presented by participants in this study and in osteoarthritis treatment studies in general; these were cited as possible reasons for difficulty in detecting treatment benefits.
It may be possible that these treatments require patience. In both articles, it was noted that response rates increased substantially beyond 4 weeks. (In the Clegg study specifically, the response rate to placebo also increased between 4 and 24 weeks, but the response rates to glucosamine and chondroitin sulfate increased more.)
Further reading:
McAlindon et al.: "Glucosamine and Chondroitin for Treatment of Osteoarthritis: A Systematic Quality Assessment and Meta-analysis." [PDF, 223 KB]
Clegg et al.: "Glucosamine, Chondroitin Sulfate, and the Two in Combination for Painful Knee Osteoarthritis." [PDF, 184 KB]
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Labels: science
Some debating about stem cell ethics
My assignment was to find, read, and discuss one or two articles about the ethics of human stem cell research. The first time I read the Fischbach article and attempted to put my response on paper, I found myself bordering on a rant about bias and authoritative influence (
grrr...), so I held off until I had the time to find and read a counterpoint article. When I finally wrote up my response, well...
Here are the results.
Read:
G.D. Fischbach, R.L. Fischbach: "Stem cells: science, policy, and ethics." [PDF, 533 KB]
K. Hug: "Therapeutic perspectives of human embryonic stem cell research versus the moral status of a human embryo - does one have to be compromised for the other?" [PDF, 190 KB]
Discuss:
Given further research and more time to think about it, I now feel that I can discuss the Fischbach article with relative objectivity (meaning I think I can avoid letting my irritation affect my critical judgment). Granted, my ill humor at this article has been percolating for almost a week. For that reason I feel compelled to issue the following disclaimer: Read this at your own discretion. (Also, please note that all emphases are my own, for purposes of highlighting certain things.)
The Fischbach article is clearly biased in favor of producing new human embryonic stem cell (hESC) lines. With regard to hESC research the authors employ words and phrases like "promise," "hope," and "relief from suffering." They're not stepping outside the bounds of what seems to be general consensus among the scientific community, namely that there is a great deal of promise in the possible applications of hESC-derived treatments. There are many possibilities that, if realized, would prove beneficial to many individuals. They say straightforwardly that producing these new cell lines requires, at present, the destruction of blastocysts, which are pre-implantation embryos consisting of 100-200 undifferentiated stem cells.
They get off to a good start, pointing out from the get-go, "The profound ethical issues raised call for informed, dispassionate debate." They ask the important questions: "What is the moral status of the blastocyst? Should blastocysts be protected under the same laws that govern research on human subjects?" Then they ruin their credibility with me in the next paragraph when they jump up on their little soapbox and start grandstanding: "Indeed," (who says "Indeed," anyway? **Warning Flag**) "the integrity of the scientific process and its independence from politics and from fundamentalist dogma are at stake." (This is not the kind of declaration that I would label as "dispassionate.") Hey, authors, I hate to point it out, but you were the ones who brought up the "profound ethical issues" and the "moral status" of the blastocyst. An individual's set of ideas about ethics and morals stem from their personal philosophy/worldview, which has everything to do with their set of beliefs ("fundamentalist dogma"), none of which can be proven scientifically. And that brings me to the whole issue of "knowledge" vs. "belief" and what exactly constitutes either one, and from here I could really go off on the "religion" of atheism/naturalism... (And hey, look, it's my personal favorite soapbox. I'll leave this alone -- for now, anyway, because a lot of my scientific ponderings seem to come back to this point eventually.)
Anyway... My point is that Fischbach & Fischbach seem to be throwing around a lot of hefty catch-phrases in a completely non-validated fashion to make their own points, which (in my own humble opinion, of course) undermines their whole position.
What kind of sealed the deal for me was one of the goals for this paper that they state near the end of the intro section: "we must reduce the emotional valence of phrases such as... 'destruction of embryos.'" This indicates to me a certain cavalier disregard for some very valid ethical concerns that they don't seem to share. I tried to read this article with an objective mindset (I really tried, I promise), but by making statements such as that one they have made it exceedingly difficult to remain objective.
Well, after the massively irritating goat rodeo that they make of their introduction, the Fischbachs get back down to business. The next couple of pages give a nice, factual, soapbox-lacking explanation of hESC development, pros and cons of research on adult stem cells, positive results seen in previous stem cell-related studies, and the basics of somatic cell nuclear transfer (SCNT). From the explanation of SCNT they trail into an attempt at defusing the issue of reproductive vs. research/therapeutic cloning; this attempt is largely successful, because it seems to be only a matter of clearing up some confusion, but I don't care because that's not the real issue here.
Then they work through the hierarchy of legal paperwork and hair-splitting distinctions that define what is and is not allowed with regard to hESC line creation and research. They wrap up their legal-political posturing with speculation about a currently (as of Nov. 2004) undecided bill that would outlaw human embryo formation by SCNT in both the private and federally-funded sectors. (I don't know whether or not it was passed into law.) Their jaw-dropping commentary on this is as follows: "This extraordinary legislation would criminalize scientific research... Effects of this chilling attack on the scientific process extend beyond hESC research. It casts a pall over all science."
(Let us pause for a moment in awed recognition of the sheer volume of B.S. that the authors have managed to cram into those three sentences.) To make a potentially lengthy criticism short, this is a perfect example of why I find the authors guilty of gross overstatement of melodramatic proportions.
The authors turn next to the ethical issues. "When does life begin?" they ask. Well, really, this is a matter of philosophical debate (first of all, define "life"), but the Fischbachs try to make it a clear-cut scientific problem. "Defining life as the moment of conception is certainly a convenient starting point," they say, "but this relies on an assumption about the value of a potential life." I will refrain from dissecting this argument in detail, but I wish to point out that their own position relies on an assumption about the lack of value of that potential life.
I'll comment on just three more items before I gleefully burn the article out of sheer irritation.
Statement: "We must weigh the moral imperative to help suffering individuals against the inherent value of preimplantation blastocycts."
Comment: As if the choice is obvious. What about the morality of respecting "potential" life? I also like how they refer to the developing embryo in such clinical terms. (Yeah, that's sarcasm.)
Statement: "We have many examples in history where attempts to outlaw fields of study have led to terrible and terrifying consequences (from Galileo to Lysenko)."
Comment: Ooh, scary words. Once again, I feel this is a case of the authors making a melodramatic overstatement. And I happen to have studied the life and work of Galileo; please enumerate these "terrible and terrifying consequences," because I'm coming up blank. (Actually, I think the overall story of how Galileo was persecuted for his science is inspiring, though sad in ending.)
Statement: "Finally, this effort should go forward because we simply will not know the answers unless we do the research. The desire to know is absolutely intrinsic to humans and has a survival value as well as a moral one."
Comment: Wow. They just kind of throw that one out there and let it hang. The statement comprising the second half of the first sentence, that we won't know until we do the research, is simple fact. The complete statement, that this is justification for the research, is opinion. (It is, in fact, an opinion that, in my infinite wisdom, I happen to disagree with.) The "desire to know" -- natural human curiosity -- yes, it would seem to be inherent in our sentient nature. Does it have a "survival value"? In many ways, I suppose, this is true; we learn how things work so as to better master our environment and therefore increase our chances of survival. But does the "desire to know" have a "moral" value? "Moral" is defined as "of, pertaining to, or concerned with the principles or rules of right conduct or the distinction between right and wrong" [Dictionary.com Unabridged, v 1.0.1]. (And hey, look, it's my soapbox again! Morality is another one of those "belief" things; no one can state factually that they know that any one thing is "right" or "wrong," only that they believe it falls into one category or the other.) Is it morally right or wrong to have this "desire to know"? This is another matter of philosophical/religious, not scientific, debate. I am astounded that these authors have the gall to wave the "moral value" flag in their defense. (Then, of course, beyond our "desire to know" there are certain things -- for example, the existence or non-existence of a "higher power" beyond our current understanding -- that we must believe to be true; we accept these beliefs on the basis of faith, because when it comes down to intellectual honesty, we must admit that these things cannot be "scientifically" proven or disproven... But that's a dissertation for another day.)
Wow, I just realized how long this is getting. I need to be done now. I'll keep the rest of this short.
As for the Hug article, I should say that I really (really, really, really) appreciated the straightforward and unbiased approach that the author chose to take. Hug didn't shy away from the fact that there are many differing opinions on these issues and that in this case, in fact, you cannot separate the philosophical from the scientific ethics. It really helped me broaden my understanding of the "ethical issues" involved in hESC research. I haven't exactly changed my opinion, but I have refined it a great deal.
Perspective is a wonderful thing.
(I would also love to go yell at the Fischbachs in person.)
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Labels: philosophy, science
