#editor peggy k

[Image: “Graphen” by AlexanderAlUS - Own work. Licensed under CC BY-SA 3.0 via Wikimedia Commons - https://commons.wikimedia.org/wiki/File:Graphen.jpg#/media/File:Graphen.jpg]

Cornell researchers get crafty in their paper published in August’s Nature.

A group at Cornell University has been playing with graphene and combining it with a technique called kirigami. Like origami, kirigami is Japanese paper folding, but with a twist– you can cut the paper in addition to folding it.

Graphene is an allotrope (form) of carbon, in which the carbon atoms are arranged into stacked single-atom thick layers of hexagons. This means you can get microscopic sheets of graphene– check out the picture above to see what a graphene sheet would look like at the atomic level! Graphene may prove very useful for scientists and engineers because it has electronic properties that may allow it to replace silicon in microchips. In order to build the graphene structures necessary for tiny nanodevices, however, scientists first needed to figure out how to manipulate graphene effectively. Noting that the mechanical behavior of the graphene was similar to that of regular old paper, the Cornell researchers decided to test the application of kirigami-inspired techniques to create their graphene structures.

The first step for the researchers was, naturally, to figure out how to move the graphene sheets. Although monolayer (single-atom) graphene sheets could be made through a process calledchemical vapor deposition, which can be thought of as “condensing” a vapor-like form of carbon onto the surface of a piece of copper, moving these microsheets around was a lot more difficult– graphene, at this thickness, very easily crumples and sticks permanently to itself. The researchers solved this problem by floating these graphene sheets in water with surfactants, which act like soap to make the sheets slippery and easier to handle.

The next step was to head to the Art Department to create full scale models of kirigami structures they wanted to build. After making the models, they began the process of building with graphene. To begin, graphene was bonded with aluminum, along with gold pads on either side of the graphene to limit direct contact from the researchers. Then, light was used to harden and strengthen only the graphene they wished to keep. Finally, unwanted graphene was removed with oxygen plasma and the aluminum removed with a weak acid. All in all, the process isn’t too much unlike its inspiration; just as kirigami requires you to trace along the patterns you want to keep with scissors and discard the pieces you cut out, working with graphene in this way is a subtractive form of manufacturing.

This allowed the team to create graphene springs and pyramid shapes that work as flexible transistors, which could become a key component in wearable electronics. It could also enhance personal technology, with the creation of folding tablets and TV screens. Medically, it could be used for comfortable heart sensors and medical devices for 24/7 use by at-risk patients. Additionally, the authors write that this graphene construction has potential to create sensors that respond to the tiniest amounts of force, improving detection. The Cornell researchers intend to pursue all avenues to find applications for this amazing new method.

Paper Source: http://www.nature.com/nature/journal/vaop/ncurrent/full/nature14588.html
Press Release: http://news.cornell.edu/stories/2015/07/paper-graphene-twists-folds-nanoscale-machines

Written by Adam M., Discoverer

Edited by Peggy K. 

[The brain goes through a process of different levels of sleep throughout the night, and it has different physiological effects, some of which are still not completely understood. Image source: http://www.katkremp.com/wp-content/uploads/2015/03/Sleep-Cycle.jpg]

If you are reading this online close to or after your bedtime, I suggest you go to sleep and come back to this in the morning. A study published in Proceedings of the National Academy of Sciences (PNAS) shows that it may be beneficial to reduce reading from back-lit devices, like computers and smartphones, before sleep.

A quick word about the importance of sleep. Most of us are aware that sleep is important for a healthy brain function and physical health. Sleep promotes learning (i.e. you might be better off sleeping the night before a big exam) and repairing of heart and blood vessels, and controls of growth and development.

When it comes to sleep, both quantity and quality matter. Quantity-wise, if you are a teenager between ages 12-18, you need at least 8.5 hours of sleep. For adults over age 18, you need at least 7.5 hours of sleep. Even just losing 1 or 2 hours of sleep per night for several days can severely impair how you perform during the day.

The study done by PNAS found that reducing reading of backlit screens before bedtime increases the quality of sleep of its participant. This is particularly pertinent as a recent survey showed that nearly 90% of Americans use some type of electronic device at 2-3 nights per week within 1 hour before bedtime. Light, including that from electronic devices, is one of the major cues that influences the human circadian clock and may contribute to sleep deficiency.

The study showed that from subjects who read from an iPad before bedtime showed:

1.Nearly 50% reduction in plasma melatonin level. Melatonin is an important hormone in regulating the circadian rhythm. Circadian rhythm is the body’s internal clock that regulates when we sleep, when we wake, and indirectly controls when we are hungry.

2.Longer time to fall asleep. While this time was only 10 minutes, this can easily add up to large numbers after a long time. Also, subjects’ circadian clocks were delayed by more than 90 minutes the following day, which may compound the problem by causing individuals to fall asleep at a later time.

3.Significantly less rapid eye movement (REM) sleep. REM sleep is the phase of sleep that stimulates the brain regions responsible for learning. Scientists have found that individuals who have REM sleep after learning a new task have increased retention of what they have learned, versus those individuals who do not experience REM sleep.


4.Taking a longer time to feel “alert” the following morning. The researchers speculate that the negative effect is possibly due to short-wavelength blue light emitted from electronic devices, but further study needs to be done to confirm and elucidate the potentially long-term effects.


References

http://www.helpguide.org/articles/sleep/how-much-sleep-do-you-need.htm

http://www.pnas.org/content/112/4/1232.full.pdf

http://www.nhlbi.nih.gov/health/health-topics/topics/sdd/why

For additional information, check out Tuck Sleep!

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By Lee H., Discoverer

Edited by Peggy K. Editor.

Question:

Do you think we should land humans on the moon again, if so, why? Also, if so, where on the moon should we land them?

Answer:


Let me start with a disclaimer: I’m setting aside the issue of whether the mission to the Moon should be funded by the government or private industry. That’s a really interesting question in its own right, but I’m not going to address it here. Let me also say that I’m not an expert on this sort of thing, though I find it really interesting and try to learn more when I can.

Disclaimer aside- yes, I think humans should absolutely land on the Moon again. The rationale for going fall into three broad categories: the philosophical/evolutionary, the historical, and the scientific.

First, the philosophical/evolutionary reason for returning to the Moon. We as a species have a unique desire to dive headfirst into the unknown with optimism and courage. The Moon may not be the unknown, sure, but it’s certainly not fully known, either. We have this spirit implanted in us that seeks a frontier in order to push it back. We see a boundary and wonder how we can get past it.[2] We should go to the Moon because we’re exploratory by nature, and landing on the Moon is exactly the sort of thing that we do.

Next, the historical reason we should go back. When America landed men on the moon in 1969, it wasn’t for science or fulfill an evolutionary urge to push boundaries. Our spaceship was a giant missile with men strapped to it- we wanted to show the Soviets that our giant missiles were better than their giant missiles. We should land people on the Moon now, not as a show of nationalism but of cooperation. The journey should be an international effort with everyone sharing in the enterprise, the science, and the benefits.

The International Space Station is a great first step along this path but we should set our sights higher. The Apollo program and its successors gave us a worldwide perspective; they gave us image after image of Earth as a single unit, not as a discrete set of divided landmasses. I think that perspective is invaluable and something that an international collaboration that sends humans back to the moon would engender.

The scientific reason for sending humans back to the Moon is pretty straightforward: humans and rovers do science differently. Humans go off the beaten bath; we meander our way to the goal; we test gravity by dropping a hammer and a feather at the same time; we stop to see how far we can throw a rock, hit a golf ball, and jump. Rovers have led to fantastic advances in science and we’ve learned extraordinary amounts from them, but the human brain notices what cameras might not and the human body interacts with objects in ways rovers certainly don’t. I think that there is more to learn on the moon and I think that human explorers – human scientists – are going to be a key part of the discovery.
Now to the second part of your question, which is where we should land on the surface. Given that I just Googled “map of the lunar surface” (I told you I’m no expert on the Moon [3]), I’m instead going to tell you what kind of place I think we should look for. These are my personal opinions, so there may be perfect places professionals have picked out that I just don’t know about. But, first, I think we should land close to where rovers have been but not follow directly in their footsteps – or their tire tracks, as it were. Second, it would be great to land near a relatively recent crater, though “relatively recent” means something very different for astronomers than it does for you and me. (The newest crater to have appeared on the moon seems to be created by a meteor that hit the surface ~2 years ago. New craters could lead to some really fascinating new science, so that’s where I think we should aim.


Thanks for asking!
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[1] Two quick links about the issue of privately-vs-government-funded space exploration. First, a debate that I went to last year at the Museum of Natural History in New York City on that very subject. Second, Neil deGrasse Tyson’s book, “Space Chronicles”. He’s very strongly pro-NASA, but the book is interesting and well-written.
[2] There’s something to be said for this being a “Western” mindset, I’m sure, but I don’t think it’s exclusively a Western, imperialist way of thinking. Humans spread across the Earth over the course of thousands of years, hardly stopping because of ice ages and surely not stopping because there were oceans in the way. Space is no more a barrier to us than oceans were to early civilizations who chose a direction and went until they found an island or a continent. Carl Sagan wrote much better about this than I do (he has gorgeous phrases like “even vicarious exploration has social utility” that I can only dream of writing), so I’d really encourage you to go to these links [1,2,3] and listen. I’d also really encourage you to read everything he ever wrote and watch all of the original Cosmos series, but that’s just me.
[3] Though, if you’re curious, I can tell you why there are so many more craters on one side of the Moon than the other.

Answered by Expert Brandon C.
Edited by Peggy K.