Tuesday, September 6, 2011

Why we need to get rid of tenure

It's another start to the new school year, although really doesn't feel like it for most grad students, as we've been working through the summer. But at least with the hype around back to school, one can't help but feel a litle excited to be going into campus today (although seeing the lineup for the bus may bring this excitement down rather quickly).

I still remember my first day, and my first semester, yes, I enjoyed going to classes that I was enrolled in, and also the occasional classes in which I was not. Learning was fun and it still is, and I solely believe that the access to education should be a basic human right, not some way for colleges and universities to make millions while putting students into major debt before they're even out of school.

But one particular professor still comes to mind from first year: my first year bio prof. Now he wasn't a bad prof, he taught (or read to be accurate) the slides of each lecture day in and day out. Now he got the job done, he got all the information across, but I thought university was the time for engaging lectures and intellectual development. For the most part it was, but I saw many of my fellow first years start to hate this class and stop going altogether, only to do very poorly and having to take it again the next semester. I remember thinking that I could do a better job and I didn't even have a degree! This is also one of the reasons I also aspire to teach at the university level.

Over the years, I saw a trend. A trend that may be evident to most students as well. If the prof is relatively new, the subject is taught with passion and interest, while the senior profs tend to lead very monotonous straight from the text lectures. Now, why this happens may be different, but I belive for the most part, this has to do with tenure. What is tenure? A prof can acquire a tenure position at a university with a history of continuous teaching for a certain number of years. What this means is that the tenured prof is pretty much guaranteed to have secured a position at that university for the rest of time. The new prof is trying to get tenure, so is trying very hard and trying to really engage students, while the tenured senior prof just doesn't care, cause they can't be fired (unless they do something that justifies that).

In my opinion, we need to get rid of this tenure position. It makes two big problems. First, the tenured prof no longer has motivation for teaching 'outside the box' and really engage young minds, and second, senior tenured profs remain well past their retirement ages and refuse to step down and allow new profs to begin their careers. I believe we need to change this tenure position, perhaps allow that profs can get tenure, but they will still have yearly reviews where their contracts can be terminated. And instead of tenure, we can have extended contracts, like 5 or 10 or 20 years, like in sports. At the end of your contract, the university can decide whether or not to extend the contract based on the yearly reviews. If not, the prof can continue to work as a nonteaching (research only) faculty until the contract is offered or apply somewhere else. What this also does is prevents contracts from being extended for retired profs to make room for new profs. And also might allow for the exchange of profs around different universities thereby increasing intellectual diversity among universities.
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Friday, September 2, 2011

Medical school reform

The bus is taking quite a long time to show up, so I'd thought I'd just post something taken from a brief conversation with my coworker and colleague Connor. Basically, its about the medical school system, which I personally believe needs to be seriously looked at. Now, don't get me wrong, the medical school system isn't the only system that needs to be changed. How grad school is structured and the way that researchers/young scientists are being abused and manipulated also needs to be changed but that is for another post. Also, I'd like to caution the readers to take my post here with a grain of salt, these are only my thoughts and I view the medical system through the other side as a grad student. However, I have worked with many medical students while working in lab during 1st year grad, my department contains many medical students so I've had the chance to take classes with them, and the building in which I work is where most of the medical school lectures occur. Also keep in mind that my information may not be accurate for all medical schools, but it is for the one I'm the closest to.

The medical system as it is now requires the premed student to satisfy 3 major requirements: good marks in undergrad (to the point where I've seen premed students sabotage other premed students, I hope this is only a rare occurrence), MCAT and volunteer work. But there is another factor that most students forget: the designated number of seats available to you depending on where you live, what university you went to, and what degree(s) you have completed. Speaking of which, right off the bat, I want to mention that students in a nonscience disciplines (especially Arts) should NOT be given a chance to apply to med school. This is not because I hate arts, but you CANNOT compare a student who has taken 4 years of full on science training to a student who has only taken the science courses required to gain admittance to med school. We need to streamline students into medicine and health from undergrad.

Getting back to my original point, universities will restrict seats from you if you're out of province, if the medical university doesn't acknowledge your home university's grading system, or if you've completed a PhD prior to applying to med school. What this basically means is that you're restricted to follow the idea of a predetermined entrance "model". On top of this, each medical university has their own board that decides who should get in (which needless to say can be full of bias). This system can restrict a very capable and ambitious premed student from entering a very good medical school simply because he/she doesn't live close enough.

This needs to be changed. The Canadian government already administers the MCAT, I suggest that they take over the admission system too. Basically, all your marks (which the goverment already has) along with your MCAT marks are attached to your medical school application that one government board decides your entrance into medical school. The student would also name their top 3 universities. This way, if a student in Victoria wanted only to study medicine in McGill, Univ. of Toronto and Queens, he/she would have an equal chance with a student already living and studied in Ontario. Plus, different universities have different admission requirements: some put more weight on marks over volunteer work or the MCAT while others do something different. Having one government body evaluating med admissions would also standardize the admission requirements, which would just be a bonus.

I also realize that this might be a lot of work for that committee, but consider this. Medical universities pretty much take a year just to let students know if they're admitted or not. I'm sure this committee, being responsible for only one purpose each year, could easily finish their task in the same time frame.

Anyways, just my thoughts. I may continue this topic again sometime in the future.
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Tuesday, August 30, 2011

And so I've returned

So it seems like its been quite a while since my last post. Although its a bit understandable why I wasn't able to post anything sooner, especially with deadlines coming up such as with the paper I am submitting, committee meeting, comp exam, and various other experiments that need to be done as I'm transitioning my project into a different field, I still feel a little bad that I wasn't able to keep this blog updated. But no more, I shall try my best to keep this going, even thought it's highly unlikely that no one really reads this, but hey, writing improves happiness (at least for me), which improves neurogenesis in the brain (I'm sure there is a reference for that somewhere; I believe it falls under enrichment in environment can increase neurogenesis in brains of rodents or something like that, which incidentally is the field my project is transitioning onto), and increasing neurogenesis will hopefully lead to increase in productivity and output. That's the hope at least. This whole idea is thanks to a TED talk by Shawn Achor linked to me by my good friend Steve Kim. I've attached the link if anyone wants to watch, its actually a very good short talk! http://www.youtube.com/watch?v=GXy__kBVq1M

Its really interesting how a research project seems to develop over time. I originally started looking at a mouse model of multiple sclerosis, which without going into too much detail, didn't really pan out. And this is one of the problems plaguing research using animal models. First of, animal models are just that, a system that is manipulated to simulate certain pathological mechanisms of a human disease so that we can study it and uncover more mechanisms or ways to "treat" the model disease. By no means does the animal model even remotely equivalent to the human disease, in fact, it could be very far indeed. But most of the time, we restrict ourselves to the idea that we're asking a specific question, so the model is the closet thing we have to test, which is reasonable, I guess. This always reminds me of a comment my colleague Wulin Teo from Univ. of Calgary who said he almost wishes we could study the actually human disease, just dissect out the human spinal cord and take a look at what pathologies are really going on in the human disease (we were talking about MS in this instance). All ethical issues aside, I kind of agree, without studying afflicted humans, how can we imagine to accomplish the treatment or even cure the human disease. Of course, many doctors (and general people) would be appalled by this comment, and by no means am I saying that we should go out and start experimenting on patients, but I feel that there is more need for directed and focused experimentation on human samples. Clinical research needs to merge more with biomedical research to have any real input into translational medicine.

I personally feel clinical research needs this influx of biomedical research, and with no offense intended, I think clinical research the way it is right now, is fickle at best. It needs more stringent research guidelines, like the ones found in biomedical research. Scientists who has published papers or are in the process know what I am talking about. For example, to validate a point or finding for publication, you must show that your hypothesis stands up using multiple different experiments such as in vitro and in vivo experiments. In clinical research (as far as I know and what I've seen), doing one experiment on one or a few patient samples is enough to publish something. Now how is that possible, the patients are likely very different (genetically) and may different environmental factors that can impact their specific illness, and what about the location of the sample and what drugs these patients were on when the biopsy was taken. Essentially, there isn't a consistent and controlled foundation from which to validate your hypothesis in clinical research (and I understand there are limitations when it comes to getting your hand on human samples).

In correspondence to this, I'd like to acknowledge a temporary but very intelligent supervisor that I've had the privilege of working for: Dr. Peter Rieckmann. His philosophy was to coordinate and facilitate communication and idea sharing between medical doctors and graduate researchers/postdocs. I really enjoyed working with my medical colleagues and fellow researchers as a team when we had bi-weekly lab meetings where everyone presented what they had managed to complete during that time. It was very helpful when, for example, you'd notice an experimental phenotype and one of the medical doctors would chime up and say that what you see looks very similar to what they notice in the patients, and as the disease progresses, they also see these other features. This would not only provide feedback from a clinical angle, but also allows you to think "outside the box" when it comes to research.

I think it was Albert Einstein who said "imagination is more important than knowledge", wherein the ability to troubleshoot a problem with creativity and imagination is a bonus to researchers, it is unfortunately one of the traits that is in danger of being lost when going through graduate school.

Tuesday, December 14, 2010

The Theory of Everything - String Theory (Part 2)

For many years, the pioneers of string theory struggled with a theory that most physicist just didn't believe in. The basic problem that had most physicists questioning the validity of string theory was that for decades it was believed that the components of the atom could all be classified as point particles, with electrons orbiting around a nucleus of protons and neutrons, which themselves were made up of even smaller 'particles' deemed quarks. In essence, what string theory says is that what we believed to be indivisible point particles were in fact tiny vibrating strings. Furthermore, strings were elegant in their design because of their enormous versatility, for example, just as strings on a musical instrument can vibrate at different frequencies making individual musical notes, in the same way, all the tiny strings of string theory vibrate in different frequencies making up all the fundamental particles and their properties in nature (known as resonance of strings). If we could only understand the properties of these strings, we would be able to explain all the matter and all the forces of nature, from subatomic particles to massive galaxies in our universe. This is the potential of string theory to be the 'theory of everything'.

However, physicists managed to come up with not one, not two, but five string theories! The five theories had many things in common but they had many differences in their mathematics. It was almost embarrassing for string theorist, to say the least, to have five competing string theories that could potentially be the 'theory of everything'.

However, in 1995 at a conference for string theory at the University of Southern California, Edward Witten, an American theoretical physicist with a focus with a focus in mathematical physics, provided a completely new perspective of string theory. He proposed and showed that in fact what we thought were five theories, were just five ways of looking at the same thing. Therefore, all five string theories could be unified into one overall theory, now called M theory, a revolution in string theory, and a possible 'theory of everything'.

However, even M theory had its caveats. Before M theory, string theory consisted of 10 dimensions, with one dimension of time and the 3 dimensions that we are familiar with, plus 6 extra dimensions that are very small and virtually impossible. But M theory demands another spatial dimension, and therefore, there must be 11 dimensions!

Another concept involves the idea that dimensions all have to do with the independent directions in which they can move (called degrees of freedom) and the more dimensions you have, the more you can do. And it became fairly obvious that at the 11th dimension allowed the strings to "stretch" to something like a membrane. A membrane could even be 3 dimensional and with enough energy, a membrane could be as large as a universe! The existence of membranes and extra dimensions reveals a new idea: our whole universe is lying on a membrane inside a much larger higher dimension of space. This raises the possibility that our universe, lying on a membrane, is just a small portion of this larger space, and possibly lies right next to other membranes that contain 'parallel universes'. Some of these universes could be like our own, or it could likely have their own unique laws of nature.

But these parallel universes are not individual compartments in the higher dimensional space, there is one thing that physicists believe that can transverse between universes: gravity. But what makes gravity special? What makes gravity different from anything else in the universe? Following the development of M theory, physicists began to investigate objects other than just strings, one example being membranes. Physicists now believe that matter and energy are actually made up of open-ended vibrating strings with their ends tied down to our 3 dimensional membrane, restricting the matter or energy to our membraned universe. However, closed-looped strings still do exist, and one kind is responsible for gravity (called a graviton). This allows the graviton to travel between the other dimensions and membranes. And if this is the case, then it could be possible to "detect" parallel universes by analyzing these transversing gravitons. And if theoretically there are intelligent lifeforms in these parallel universes, then it could be possible theoretically for this parallel to be very close to us, and thus, theoretically we could "communicate" with these lifeforms using gravity.

This concept of parallel universes could also explain the origins of our very own universe. If we were to turn back time, going further and further back, where our universe was just a very small highly dense point in space we would see that all the laws of physics just break down, and are no longer valid. Not only that, but we also have the problem with the process that initiated the "creation" of our universe, the so-called Big Bang. One of the most imaginative models suggests that the origin of the Big Bang lies in the movement of the parallel universal membranes. According to this proposed model, some time before the Big Bang, two membranes began to drift towards each other until they collided at a specific point, releasing this incredible amount of energy, leading to the Big Bang, and eventually, our universe. What is even more intriguing is that scientists believe that this was not a special event. In fact, it could be absolutely possible that two membranes could've collided prior to the creation of our universe, other membranes could be colliding giving rise to other parallel universes, and this collision will continue to occur in the future. If this idea is true, then it means that somewhere out there is an adjacent membrane on a collision course with our very own universe. However, there is a major problem. The mathematics and laws of nature break down at these early time points, so it is almost impossible to predict what would happen if two membranes were to collide. Would it lead to another Big Bang, or are there other inter-universal possible scenarios?

Of course, these theories seem very amazing and elegant, but they mean nothing if they cannot be proved "in the lab", so to speak. Two of the world's largest particle physics laboratories, fermilab and CERN, are creeping ever closer to answers. The concept here is that hydrogen atoms are electrocuted with huge amounts of electricity, and then they are stripped of their electrons. These energized protons are accelerated through a long underground tunnel system, and just as these protons approach the speed of light, these protons are collided with protons travelling in the opposite direction. Most of the time, the collisions are just glancing blows, but occasionally, there is a direct hit and the result is an explosion of subatomic particles. The hope is that among these subatomic particles is the graviton, which is closed-looped according to string theory, and can travel into the extra dimensions and therefore, the absence of the graviton could be detected.

Another experiment on top of the list for both scientists at fermilab and CERN is the idea of super symmetry, a central prediction of string theory. In essence, super symmetry predicts that for every subatomic particle there exists a paired heavier superpartner (also called a sparticle). If these superpartners exist, they are likely extremely heavy, in fact they may be so heavy that they may not be able to detected with today's "atom smashers" at fermilab and CERN. Although the existence of superpartners won't prove string theory, it will definitely be circumstantial evidence that we are on the right track.

But what if we are unable to find the graviton, or superpartners or even extra dimensions? What if we are unable to find any evidence for string theory? Could string theory be incorrect and is not the road into the 'theory of everything'? The fact of the matter remains, about a century ago some scientists believed they had figured out the laws of the universe, but Albert Einstein came along and revolutionized our views of space, time and gravity. Quantum mechanics revealed a world of unpredictability and bizarre. Regardless of the obstacles, scientific curiosity will keep us going and we will continue to explore the unknown. Undeniably, these new theories of physics shows us the imaginative and creative potential of the human mind.

Monday, November 22, 2010

The Theory of Everything - String Theory (Part 1)

In 1968, a young Italian theoretical physicist named Gabriele Veneziano was searching for equations that would explain the strong nuclear force, which can be defined as the extremely powerful force that binds the neutrons and protons together in the nucleus of atoms. As sometimes the story is told, Gabriele happened upon an old mathematics books where he discovered the Euler beta function, first studied by Leonhard Euler and Adrien-Marie Legendre.

He noticed that when the function was interpreted as a scattering amplitude (In quantum physics, the scattering amplitude is the amplitude of the outgoing spherical wave relative to the incoming plane wave in the stationary-state scattering process), it contained many of the physical properties needed to describe strongly interacting particles.

This amplitude, later named the Veneziano amplitude, is interpreted as the scattering amplitude for four open string tachyons (which will be simply defined here as a hypothetical subatomic particle that moves faster than light).

However, what is more likely is that the discovery of the equations was not accidental but in fact the outcome of intense research and the correlation to string theory was an accidental discovery. But however it was discovered, Veneziano's work led to a model that explained the strong force by a field theory of strings. This was the birth of string theory.

The Euler beta function was passed from colleague to colleague, until it came across the American physicist Leonard Susskind. He understood that this formula explained the strong force mathematically but he figured out that beneath these symbols was something simple, abstract and elegant. The story goes that " a young physicist got stuck in an elevator with Murray Gell-Mann, one of physics' top theoreticians, who asked him what he was working on. Susskind said he was working on a theory that represented particles 'as a kind of elastic string, like a rubber band.' Gell-Mann responded with loud, derisive laughter." He noted that this formula seemed to explain particles with an internal structure, which could stretch and compress and even oscillate. However, as revolutionary as it sounded, it was mainly rejected by the scientific community. It appeared that string theory was dead.

Particle physics was embracing the idea that particles were indeed points and that microscopic particles smashed together at high speeds would lead to release of multiple even smaller particles. But what is revolutionary here is that physicists were not only discovering the constituents of matter, but they realized that the forces of nature could also be described in terms of particles. The way to imagine this is to imagine a game of catch where particles of matter are throwing a particle of force (called a messenger particle) back and forth. The more messenger particles that are exchanged between the particles of matter, the stronger the force, and this is what we feel as force. Experiments by physicists confirmed these predictions by the discovery of messenger particles for electromagnetism, the strong force, and weak force. Using this model, scientists believed that we were once step closer to unifying the forces. To understand this further, imagine we were to rewind time to moments just until after the big bang, when the universe was very much smaller and very much hotter, the messenger particles for electromagnetism and the weak force would have been indistinguishable and would have been united as the ‘electroweak force’. And theoretical physicists believe that if we went further back in time, the electroweak would be united with the strong force. Although that has yet to be proven, quantum mechanics does explain how these three forces operate on the subatomic level. And now we have a consistent model of elementary particle physics that allowed the explanation of all of the interactions – the strong, weak and electromagnetic forces – in the same context known as the ‘standard model’. However, the standard model has a major missing piece. It does not include an explanation for the force that governs the universe, gravity.

Eclipsed by the standard model, string theory started to become very indiscernible by the scientific community. And although, the early pioneers of string theory believed in the model and continued to explore string theory, they found several problems. Among other things, early string theory predicts a particle that can travel faster than the speed of light, an unnatural and hypothetical particle called a tachyon. Furthermore, the theory also predicts 10 dimensions, which at the time was impossible to believe. And to make complications worse, many of the predictions were not testable experimentally classifying this theory as more of a mathematical framework for building models than a physical theory, and to say that string theory is a theory of everything is a failure. Jim Holt, a journalist, was noted as saying “…dozens of string-theory conferences have been held, hundreds of new Ph.D.s have been minted, and thousands of papers have been written. Yet, for all this activity, not a single new testable prediction has been made, not a single theoretical puzzle has been solved. In fact, there is no theory so far—just a set of hunches and calculations suggesting that a theory might exist. And, even if it does, this theory will come in such a bewildering number of versions that it will be of no practical use: a Theory of Nothing.”

By the early 1970s, only a few physicists were still struggling with the concepts and ambiguous equations of string theory. John Henry Schwarz, an American theoretical physicist, was working on some of these inconsistencies, one of them specifically the prediction of a mass-less particle never seen in nature. For several years, he struggled with the equations, but nothing worked, the equations would always seem unruly and messy. Just as Schwarz was thinking about abandoning the theory, he had an idea. What if his equations were describing gravity? That would mean rethinking the size of these ‘strings’ of energy.

By supposing that he was studying the theory of gravity, he had to tremendously change the view of how big these strings were. By suggesting that these strings were actually hundred billion billion times smaller than an atom, the mass-less particle could now be viewed as a ‘graviton’ – the particle believed to transmit gravity at the quantum level – and string theory had described the missing piece of the standard model. Schwarz submitted his results for publication; however, there was very little reaction from physicists. However, Schwarz was not discouraged from his bold predictions. He envisioned that if strings could describe gravity at the quantum level, they must be the key to unifying the four forces – electromagnetic, strong force, weak force, and gravity.

Regardless of this incredible idea, the equations of string theory still contained major mathematical anomalies, and the only way to make string theory viable was to get rid of these anomalies. Schwarz and Michael Green, a British physicist, decided to calculate and it all came down to one equation. The story goes that on one side of the blackboard they got 496. And if they managed to get 496 on the other side, this would prove that string theory was free of anomalies. This was termed the Green-Schwarz anomaly cancellation mechanism and indeed, the two numbers did match and this meant that string theory was free of anomalies and it had the mathematical depth to encompass all fours forces, and the possibility of unification of forces, a dream that Einstein had expressed. This time the reaction of the scientific community was enormous and interest in string theory skyrocketed.

This updated version of string theory seemed capable of explaining all the components of nature. If one imagines the components of an atom: electrons orbiting a nucleus containing neutrons and protons, which are made up of even smaller parts called quarks. String theory explains that the particles making up everything in the universe are made of even unimaginably small strands of energy that look like strings. Furthermore, just as strings of musical instruments have unique vibrational patterns or frequencies that create what we hear as musical notes, the different way that these strings oscillate give particles their unique properties like mass or charge. So in essence, the only difference in particles those make up matter and the particles that make up the forces is the way these tiny strings resonate. And it’s this elegant idea of string theory that one can view the universe as one big musical cosmic symphony.

And it’s this idea that bridges the gap between the unpredictability of the universe on the subatomic level as depicted by quantum mechanics and the smooth picture of the universe on the large scale as depicted by Einstein’s General Theory of Relativity. In essence, string theory ‘spreads out’ the unpredictable nature of a point particle into a string, thereby bringing an ordered fluctuation of quantum mechanics that allows it to stitch together with general relativity.

Regardless of the great advances made so far in string theory, there is still one major criticism, and this leads us back to the Heisenberg uncertainty principle which states that, In quantum mechanics, certain pairs of physical properties, such as position and momentum, cannot be simultaneously known to arbitrarily high precision.

Simply put, the more precisely one property is measured, the less precisely the other can be measured. Therefore, at the distances being studied, experiments cannot be used to validate or refute this theory. And thus, whether string theory can be considered a theory of physics or a theory of philosophy is still highly debated.

Another concept that makes string theory even harder to prove is that one must also consider that this theory predicts extra dimensions of space. Most people consider that the universe has only 3 dimensions and one more dimension of time. We know that Einstein showed that gravity can be visualized simply as warped space-time. Theodor Kaluza, a German mathematician, suggested that electromagnetism might also work the same way. He proposed a hidden dimension where space is warped to facilitate the electromagnetic force. But how can we visualize this extra dimension. Oskar Benjamin Klein, a Swedish theoretical physicist, proposed an unusual answer. Imagine a line that extends between two points, such as a rope tied between two poles. From a distance, we cannot see that the rope has a thickness, and it is simply a line with a single dimension. However, if we were very close to the rope, we would see the presence of a second dimension that wraps around the rope, a dimension that we can travel around the rope in a clockwise (or anti-clockwise) motion. Therefore, dimensions come in two forms, either long like the length of the rope, but can also be very tiny, like the circular direction that wraps around the rope. Kaluza and Klein suggest that the universe may be just like this rope, with both big and extended dimensions, like the ones we know about, but also with small curled up dimensions that are smaller than atoms, dimensions we cannot possible see. Kaluza and Klein theorize that if we were able to decrease our size to the size smaller than an atom, we’d find one extra circular dimension located at every point in space. The concept that extra dimensions exits all around us lies at the heart of string theory, as string theory demands 6 extra dimensions curled up into different shapes at the subatomic level. But how do these extra dimensions of space curled up into unique shapes have any impact on our everyday world? Recall that strings can resonate at specific frequencies, and that this in turn dictates the properties of the particle. When you change the shape of the space around the string, you also change the frequency at which the strings vibrate.

Monday, October 4, 2010

The Earth is Slowing...

The Earth's rotation is the rotation of our planet around its own axis. At present, the angular speed of Earth's rotation in inertial space is 7.2921150 ± 0.0000001 × 10−5 radians per SI second (mean solar second). Multiplying the value in rad/s by Earth's equatorial radius of 6,378,137 m (WGS84 ellipsoid) (factors of 2π radians needed by both cancel) yields an equatorial speed of 465.1 m/s or 1,674.4 km/h.

But is the Earth's rotation slowing down? In short, yes, due to a transfer of Earth's rotational momentum to the Moon's orbital momentum as tidal friction. And with that increase in the Moon's speed, it is also causing the Moon to slowly recede from Earth. The slowing rotation of the Earth results in a longer day and also a longer month. Once the length of a day equals the length of a month, the tidal friction mechanism will stop. But not only is the Earth losing it's kinetic energy to tidal friction, but also other forms of friction.

This on going change causes tremendous dynamic movement within the Earth as it adjusts its shape. It is gradually changing its shape from that of an oblate spheroid with a bulging equator and flatter pole regions to that of a more perfect sphere to conform with the changing conditions. This slow continual change of the Earth's interior has set up tremendous dynamic pressures and stress within the Earth's crust as it endeavors to conform to the ever changing mantle upon which it floats. It is the imbalance between the rotational inertia and gravity that cause the dynamic movements of the continental crustal plates as the crusts shifts and crunches to fit into the ever changing area.It is this constant change thats causes earthquakes to occur, volcanoes to erupt and the Earth's vast mountain ranges to rise. As the equatorial oblate shape of the Earth shrinks, the immense resulting pressure within the mantle causes it to gradually ooze upward creating the Atlantic and Pacific ridges.

Does this spell a slow but inevitable doom for our planet, or are there more imminent threats to our survival? In any case, we are on this Earth but only just a moment, and will be gone just as quick.

Arthur N. Cox, ed., Allen's Astrophysical Quantities p.244.

Thursday, September 16, 2010

Hey you guys work with stem cells, right?

Here is a question I received from a friend asking about the differences between embryonic stem cells and induced pluripotent stem cells:

Questions: A friend of mine posted an article saying that embryonic stem cell research is useless because it can all be done with induced pluripotent stem cells. That seems incorrect to me. Could you give me some insight into this issue?

My Answer: Sure, you're right. Embryonic stem cells are NOT the same as induced pluripotent stem cells. This is a common statement that people (usually idiots who read newspaper headlines and don't bother to actually read the research). Also the reason for this could also be because the term "stem cell" is such a buzz word now and almost everything is called a stem cell. Lets review a few of the criteria for a "stem cell".

1. Immortality
Incorrect, stem cells are NOT immortal. They can generate many progenitor cells over their lifetime by assymetrical cell division, but they are by no means immortal.

2. Can form multiple cell types. This has really only been shown in vitro. So a "stem cell" is put into a media and then forms different cells. Not really been conclusively shown in vivo, and if it was conclusive in vivo, we'd have cured spinal cord injuries by now. Fact of the matter is, the way cells behave in vitro is not the same as how cells behave in vivo.

Also, certain "stem cells" only produce 1 type of cell. A muscle satellite cell is a stem cell, but it only produces only 1 cell type (muscle cells). But it is present in senescence and has the potential for many cell divisions.

3. Stem cells are special and other cells cannot normally become stem cells. There is evidence that liver cells can undergo a dedifferntiation following injury/loss of regions of the liver.

In terms of ES vs. iPS cells:

ES and iPS cells are similar yes, but NOT THE SAME. ES cells come from 5-6 day old embryos after in vitro fertilization. These cells can turn into all cells of the body. iPS cells come from adult cells that are reprogrammed to "act" like embryonic stem cells. I believe you can activate 4 specific genes that can "reprogram" an adult cell to an iPS cell. They can also form all cells of the body.

But the issues arise when we look at the methods of creating iPS cells. The methods vary between labs, the cells produced by different labs behavior differently, and simply, comparing ES and iPS cells on a genetic level shows that DIFFERENT GENES ARE ACTIVATE between ES and iPS cells. For example recently, European and Israeli researchers found that when they created iPS and ES cells both containing a mutation that causes fragile X syndrome, the two groups of cells behaved very differently, with the iPS cells not even activating the mutated gene (FMR1). It is possible (if not very likely) that other genes may likewise escape the reprogramming process leading to iPS cells.