Today we learn that scientists at Johns Hopkins found a way to turn blood cells back into stem cells. Meanwhile, a longstanding theory about human pregnancy faces a formidable challenger, and a revolutionary new material comes from a surprisingly common, and renewable, resource. Finally, scientists observe evidence of gravitational waves. That’s all ahead in today’s Friday Roundup.
They Turned Blood Cells into Stem Cells
Yes, you read that right.
This is the breakthrough that ought to successfully destroy any controversy over research into stem cells as a medical technology. Researchers at Johns Hopkins have discovered a way to transform blood cells back into stem cells, and to do so reliably.
For those who are unaware, stem cells are cells present while the human embryo is developing. They are “template” cells which haven’t yet had their specialized genes turned on. In other words, they can transform into any type of cell in the human body.
Dr Elias Zambidis and his colleagues published the results in the Public Library of Science on August 8th. The same team also successfully transformed blood cells directly into heart cells last spring.
The method also breaks away from those used by other researchers. Typically, a genetically engineered virus is used to insert genes into a cell in order to reprogram it and transform it back into a stem cell, or into a different type of cell. Unfortunately, this can also result in mutations that can lead to cancer in the transformed cell.
The new method avoids the need for a virus. Instead, it uses structures called plasmids, which are DNA rings that typically replicate inside the cell’s nucleus before dying.
(In one of the first interviews on this site, I spoke with Frank Abernathy about the controversial possibility that plasmids, circular DNA pieces, are actually plugged into sites in the DNA strand.)
The blood cells, which came from umbilical cords, were treated with growth hormones. The plasmids then carried the DNA into the cell. An electrical impulse allowed the cell surface to open up and allow the plasmids through. The cells were then cultured in bone marrow cells.
A Materials Science Breakthrough…From Wood Pulp?
Nanocrystalline cellulose, or NCC, is being hailed by some as a new wonder technology. The US National Science Foundation currently expects it to become a $600 billion industry by 2020. It’s transparent, conducts electricity, and has a strength to weight ratio eight times higher than steel.
…and it’s made from wood.
While the new material is isn’t quite on par with some of the promises made by carbon nanotubes (with about 10 times the conductivity, 5-20 times the strength, and special thermal capabilities) it can be made at a very low cost.
It is expected to sell for a just a few dollars a kilogram.
And it’s being put into mass production right now. On July 26, the first US factory opened up in Madison, Wisconsin, run by the US Forest Service. A plant in Montreal, Canada has been producing a tonne of NCC each day since November 2011.
The technology will be implemented in body armor as well as flexible computer displays and tablets, and will surely find other uses.
Here’s how it’s manufactured:
- Wood is “purified” by removing certain chemicals
- The wood is milled into a pulp with grains about 1000 times smaller than usual
- Acid is used to remove further impurities
- The material is concentrated into a crystalline paste
- The paste is processed into strands called nanofibrils
The material can be made from twigs or sawdust. Wood pulp is already widely used, primarily in the paper industry. It is already successfully farmed and doesn’t require cutting down forests.
This makes it a renewable resource, although it’s important to recognize that energy used to process and transport it would still contribute to CO2 emissions. However, since trees recapture CO2, it’s overall environmental impact is comparatively low.
Related: Nanotechnology For Dummies
Empirical Evidence for Gravity Waves
Einstein’s theory of general relativity predicts all kinds of things that sound crazy to the uninitiated. It predicts that objects in free fall are actually “at rest,” such that space itself is falling toward the earth. It predicts that time ticks slower in gravitational fields than it does away from them. It predicts that gravity itself is the result of dimples in space and time.
These predictions may sound crazy, but they’ve been empirically verified for quite some time. In fact, your GPS system wouldn’t work properly if it wasn’t built to take these factors into account.
But not every prediction of general relativity has been tested. One of these predictions is that when massive objects accelerate, they should give off gravity waves. These are waves that actually compress and expand space itself.
Incredibly sensitive instruments such as LIGO aim to measure these waves directly. So far, they haven’t been spotted. But observations of two collapsed stars, white dwarfs, appear to have observed the phenomenon indirectly.
In short, the white dwarfs’ orbits are decaying, which means energy is being lost. The energy has to be going somewhere, and there has to be a mechanism to explain it. The physicists devised several models to explain the loss of energy, and the only model that fit was gravitational radiation.
While this is by no means a smoking gun, it is strong evidence and exciting news for general relativity. (For an intro to relativity, this post meant for kids is just as useful for adults).
Evidence Contradicts a Long Held Theory of Human Pregnancy
It’s a widely held theory that human babies are essentially born before they are done developing. Walking upright made wide hips a problem, but humans were also evolving to have bigger brains. Evolution’s only way to solve the problem was by squeezing the human out early, before their brain was fully developed.
The theory is popular for understandable reasons. Anecdotal accounts of women losing the ability to run after developing hips abound, and human babies seem decidedly helpless in comparison with the babies of most animals.
But Holly Dunsworth and other researchers decided to put the theory to the test. It turned out the evidence told a very different story.
Studies of women on treadmills found that women who had wider hips were not at all slowed down. This suggests that a larger birth canal may not have been an obstacle for our ancestors after all.
The team also analyzed well-established research to determine if human gestation was shorter compared with other animals. It turned out to be just the opposite. Babies were born later than would be expected based on the size of the human body.
In fact, babies themselves were larger than would be expected.
Realizing that body size was related to metabolism, Dunsworth brought in Peter Ellison from Harvard and Herman Pontzer from Hunter College, two experts in the subject.
Together, they developed a hypothesis suggesting that energy was the real issue. According to the new view, mothers simply don’t have enough energy to continue gestating. This is due to a limit in the number of calories humans are capable of burning in a day.
The model predicts that if a woman were to give birth to a baby as physiologically advanced as a baby chimp, she would need to gestate for 16 months, which would require more energy than her body is capable of producing.
In other words, the hips don’t have anything to do with it. It would simply be impossible for the human body to build a larger or smarter baby in the womb. This is why development has to continue outside of the body, and human babies are comparatively helpless.