Check out this summary of results on aging in nematodes. The layman’s summary is this:
Aging is thought to be due to accumulated damage. As we age our bodies get lots of microscopic injuries and accumulated cellular damage. Over time it adds up and our bodies break down and we die. This is the prevailing hypothsis because it’s easy to see the mechanism for how it came to evolve.
An alternate hypothesis is that our genes dictate that we age and die, and it’s programmed into us. So rather than breaking down, aging is the result of changes in metabolic regulation.
This study finds evidence supporting the latter model, which is pretty interesting. To summarize their experiment they used gene-chips to exhaustively search for genes that change their expression level in old worms, and linked many of them to a single regulatory protein (transcription factor). Then they tried to put stresses on young worms to see if they could increase the level of this transcription factor, effectively making the worm age faster. They were not able to, which indicates that the transcription factor levels are not a function of stress. Of course, this is only true if they were using the “right” stresses on the worms.
In any case, I’m always excited to see work done that supports any sort of programmed-senescence model, because it points toward the possibility of regulating aging by only tweaking a few things.
I wanted to share this great youtube video demonstrating a classic kitchen-science non-newtonian fluid: cornstarch and water. The creator puts this mixture on a cookie plate and presses the plate against a subwoofer. The result is pretty great!
A little background on newtonian fluids
In a newtonian fluid the shear rate (rate of flow) is directly proportional to the shear force (how hard you push on the liquid), and the constant of proportionality is the viscosity. So if you double the shear force, you double the shear rate. In a non-newtonian fluid that’s not true, and it can be untrue in different ways. The most straightforward comment is that you can get a non newtonian fluid if the viscosity is not constant. In the case of cornstarch and water you have a fluid where the harder you shear it the more viscous it gets. Compare this to water where the harder you shear it the faster it flows.
Wikipedia has a decent article on non newtonian fluids that you could check out.
A group of oceanographic scientists are in the process of publishing results indicating that the ocean has stripes. They used successive levels of data filtering to remove large scale variations like currents and waves and temperature gradients, and they were left with these bands of very small variation in temperature and velocity.
An interesting observation here is that they repeated their approach on the output from a Japanese computer running the “Earth Simulator” and found very similar stripes in the output from that model.
Maybe I’m just overly skeptical, but it seems to me that if you run a bunch of data filtering and end up with a bunch of surprisingly fine-scale features you have to wonder if it’s an artifact of the analysis. And the fact that they found the same features in the model output, when presumably the model wasn’t programmed to have this behavior, seems to indicate that the stripes are coming from the data filtering and are not real phenomena. Otherwise that seems to say that the Earth Simulator model is so accurate that it was predicting previously unimagined phenomena in the ocean, which would be pretty remarkable in itself.
For the record: I’m not an expert in oceanography, I’ve just got some experience modeling physical systems. They may be right, and there may be tons of stripes overlaid on the ocean. I’m sure their first thought was that it was an artifact, and it must have checked out after reviewing the analysis. It just seems a little fishy.
I came across this in summary for at Ars.
Ars technica wrote an article using explanations of homeopathy as an example of how you can tell pseudoscience from real science. It’s not the most clearly written argument, but it covers the points.
A quick explanation of homeopathy: you put some “stuff” in water, then you dilute it. The real kicker is that in homeopathy you dilute the original solution so much that there are zero molecules of the original “stuff” in it. In fact, it’s claimed that the more you dilute it the more powerful it gets. When you drink the water it will have medicinal powers as a result of the water having “memory” of the stuff that was in it. And there really are zero molecules of stuff in the water. Let’s be clear: homeopathy has beneficial effect only through the placebo effect. There’s no evidence at all that there is such a thing as “water memory” or an inverse dose response (more diluted water works better).
Continue reading ‘Homeopathy as a case study of bad science’
A pretty cool development here for fans of gene therapy. The essence of gene therapy is that if a person is born with a defective copy of some gene you can insert a good copy into a critical set of cells in that person and restore the broken functionality. In this case the researchers injected therapeutic viruses into 12 patients brains and saw therapeutic benefits for parkinsons sufferers.
The reason you use viruses for gene therapy is that a virus has evolved to attach to a cell and inject it’s own genes to force the cell to make copies of the virus. It’s possible to gut the virus and insert your own genes of interest, so when the virus infects a cell, all it does is inject your genes. There’s no replication, no spreading viruses, etc. Gene therapy has had a pretty rocky history though, and not a lot of medical success.
Continue reading ‘Gene therapy for parkinsons has successful phase 1 trial’
I came across a short piece in the New York Times recently that’s worth pointing out. It’s about a particular startup in the Bay Area that’s focused on using metabolic engineering to produce anti-malarial drugs and the next item on their agenda is fuel.
For the layperson, metabolic engineering is a step beyond genetic engineering. Metabolic engineering involves creating a new network of complementary reaction pathways within a cell, essentially creating whole new ways of making biological products. In a big picture sense, metabolic engineering treats the cell as a factory, and adds or optimizes structures within the cell for some design purpose.
Continue reading ‘Metabolic engineering as path to medicine and energy’
Regarding the mysterious bee die-off
Since October 2006, 35 per cent or more of the United States’ population of the Western honey bee (Apis mellifera) – billions of individual bees – simply flew from their hive homes and disappeared.
It’s an interesting situation, and not to trivialize it but it sounds like paraphrasing Douglas Adams. “So Long and Thanks for All the Pollen.”
I came across this pretty neat site that compares search terms across two search engines, Yahoo and Google.
Enter a search term and the row of dots indicate the order in which results appear (e.g. the far left result is the first result for each search engine). The blue dots are results which occur in both Yahoo and Google, and they have a blue line connecting the matching results. This is a away to visually see whether Google and Yahoo have similar rankings for pages on a topic.