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Morphing Mice

Filed Under: Science in the News by keand — Leave a comment
April 23, 2013

Growing up in the 1990′s, I was familiar with the usefulness of laboratory mice from a very young age, thanks to my hours spent watching Pinky and the Brain. Since that time, however, lab mouse technology has improved quite a bit–scientists have found a way to make mice function more like humans. If you’re feeling skeptical about how a mouse could become man, not to worry, these lab mice won’t look like people any time soon. Rather, scientists have discovered a way to replicate the human immune system in mice, enabling them to figure out how an individual immune system will respond under various medical conditions.

labMice_1632902c

Though mice have traditionally been used for testing medications and response to treatment–essentially anything scientists can come up with–mice with modified immune systems have huge implications for cancer treatment and the development of pharmaceuticals. Studies have been done to determine how similar the immune systems of mice and humans are, and these studies suggest that while there are a number of similarities, there are many differences as well. These differences could explain why tests conducted on mice in the laboratory don’t always translate to humans the way that they are expected to. By reprogramming mice with the immune systems of individual people, however, scientists have learned that discrepancies can be eliminated.

(Source: http://www.telegraph.co.uk/health/healthnews/7699915/Pain-for-laboratory-mice-revealed-in-human-facial-expressions.html)

The specifics are relatively complicated but, essentially, mice can be injected in certain parts of the body with human cells, which allows a small-scale replica of a human immune system to develop. The genetically modified mice that are injected, called SCID mice, do not have immune systems of their own, which is why they are able to accept and grow stem cells or white blood cells from humans. This process is so exceptional because it requires genetic material directly from humans to work, meaning that the exact immune system of a sick individual can be duplicated in a low-risk manner. For example, once the immune system of a cancer patient has been replicated, scientists can inject the mice with the cancer as well, before trying any treatment combination desired. Though the cancer can take several months to grow in the injected mice, studies suggest that the wait is well worth it. In one study by Manuel Hidalgo, SCID mice with human immune systems were used to find treatments for 94% of the participants. Treatment reactions observed in the patients mirrored reactions first seen in the mice.

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 (Source: http://www.cancer.gov/cancertopics/understandingcancer/immunesystem/page38)

Such mouse technology may not be readily accessible, and it certainly requires patience from those who are able to use it, but the science is rapidly progressing, and researchers are hopeful for the future. An assortment of obstacles are present–some cancers will not grow in mice at all, while organs like the liver in mice can respond to drugs differently than they do in humans–but scientists have not been deterred. In fact, many are working on recreating human organs in lab mice as well, to make testing more accurate. The scientific road ahead might be a long one, but this technology could help us to understand and treat ailments from HIV to arthritis to diabetes. Considering the work that has already been done with man-mice, the future impact of these studies is likely to be substantial.

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The Science of Sleep

Filed Under: Biology by keand — Leave a comment
April 5, 2013

I’ll be honest, most days I find it reasonably difficult to make it through the day without falling asleep at one point or another (never in class, of course), yet when I should be sleeping, I’m wide awake. When I finally get to bed, I keep myself awake thinking about when I’m going to fall asleep, and before I know it my alarm is pulling me from sleep into which I can’t remember falling. As a result I often find myself wondering why it is that I can’t stay awake during the day, which raises the question, what exactly is sleep? Equipped with plenty of coffee, I decided to put my curiosity to use and explore how sleep works. As it turns out, for such a common activity, sleep seems to be just as mysterious to others as it is to me.

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(Source: http://www.time.com/time/health/article/0,8599,1903838,00.html)

For starters, falling asleep is a more gradual process than many of us might realize. Once you close your eyes, your brain slowly begins to tune out external stimuli as your brain waves begin to slow. This slowing of brain waves is called stage 1 of sleep, which is characterized by short periods of brain activity just like those experienced when you are awake. For this reason, stage 1 is considered to be the transitional stage, as the brain becomes less alert. Many people awoken during stage 1 of sleep do not realize that they have been asleep at all, but as brain waves slow further and the brain activity of stage 1 sleep fades, stage 2 begins–this is what scientists agree marks the beginning of true sleep.

Before long, brain waves become even slower, but short periods of faster waves can be observed from time to time. This marks the beginning of deep sleep, also known as stage 3. As deep sleep continues, the bursts of fast brain waves stop, and the brain enters stage 4 sleep. There is no muscle activity during this stage of sleep, which helps to explain why it is so difficult to wake people from stages 3 and 4, yet those who sleep walk do so while they are in deep sleep. After being asleep for about an hour and a half, the brain experiences REM (or rapid eye movement) sleep. While REM might be the most important stage of sleep, it differs considerably from other stages–brain waves become more rapid and less controlled than in other stages of sleep, and it is during this time that we dream.

 

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(Source: http://www.proactivesleep.com/bodilycycles.php)

The stages of sleep are important to understand, but brain waves aren’t the only things changing when we sleep. As we stop responding to external stimuli, our breathing begins to slow, and remains fairly constant until REM sleep occurs, during which it increases. In addition, our body temperatures drop by about a degree while we sleep, and our heart rate slows to reduce blood pressure. A number of physiological processes slow in order to conserve energy, but some, such as the growth and repair of cells, actually increases during sleep. This is one of many reasons that it is important for teens to get enough sleep.

At the awkward age of nineteen, technically I belong to this category of strange people commonly referred to as teenagers. Interestingly enough, studies suggest that while teens need more than nine hours of sleep each night, their internal clocks prevent them from feeling tired until after ten o’clock at night. This might explain why I’m frequently awake when I need to be sleeping, and barely conscious when I need to be awake. Studies also show, however, that I’m certainly not the only one who experiences this phenomenon–one study showed that 90% of teens were sleeping less than the recommended nine hours, while another suggested 63% of college students weren’t sleeping enough either. While some colleges and universities have tried to combat sleep deprivation among students, the problem is still widespread. I can only hope that what I have learned in writing this will help me better schedule my time in the future–given all this sleep on my mind, I think I’ll go take a nap.

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Turning the Tables: The Return of the Record

Filed Under: Physics by keand — Leave a comment
March 22, 2013

Rumor has it that analog music is making a comeback, a theory which my roommates and I perpetuated by returning from spring break with a record player. As excited as we were, we didn’t expect to become so knowledgeable about how exactly record players work, but one technical problem after another turned into quite the learning experience. As it turns out, turntables are all about physics, from they way records are made to how they are played. Though generations previous to my own are more likely to be familiar with analog music, I wonder if they can’t learn something from my experiences too.

Edison’s original phonograph.

The modern day record player started from reasonably humble beginnings in the form of the phonograph, invented by Thomas Edison in 1877. Edison’s phonograph was capable of recording sound using a needle and thin foil–when he yelled into the mouthpiece of his device, the sound waves from his voice caused the needle to vibrate, etching his words into the foil. Using a second needle and an amplifying device, Edison was able to convert his etchings back into sound.

(Source: http://memory.loc.gov/ammem/edhtml/edcyldr.html)

Though the look of the record player has changed dramatically since Edison’s first experiments with recording sound, the concept behind how it works is still fundamentally the same. A number of small parts work together to reproduce sound from the grooves etched in the vinyl records. First–as my roommates and I had to discover the hard way–the drive belt is responsible for making the turntable (and therefore the record) spin. The belt is stretched around a motor and a disk underneath the turntable, so that when the player is turned on, the motor moves the belt, spinning the disk. But how exactly does physics play in? The force of tension in the belt is what effectively pulls the disk and turntable above it, and keeps them moving around. Without tension in the belt, it would easily slip off of the motor, and the turntable would no longer spin.

You can tell that there is some tension in the drive belt because it appears to be taut.

(Source: http://www.yourspares.co.uk/parts/ys119067/black-172-mm-turntable-drive-belt-F399ZT.aspx)

The drive belt is just one component of the record player however, accompanying the stylus and tone arm, as well as the cartridge and an amplifier. Not only are there different forces that must be taken into account with these additional components, but magnetism and currents are involved too! The stylus, or  needle, is housed in casing called the cartridge, that is attached to one end of the tone arm. This is what is placed over the record to make it play. (I suspect it might be helpful to look at a picture.) In order to prevent scratching the record however, the force of the needle at the end of the arm needs to be balanced, so that the pressure it exerts on the record is minimal. This is achieved by the presence of a counterweight at the opposite end of the tone arm. Although the counterweights used in record players are quite small, the physical principle is no different than counterweights in things like elevators–many devices would not be able to balance and work without them!

The cartridge also holds the key to making records loud enough to hear. In addition to the stylus, the cartridge houses small magnets and coils that are responsible for amplifying the sound. When the needle moves over the grooves in a record, it vibrates, which causes the magnets to vibrate also. When the magnets experience this force, it changes the magnetic force that exists around them, which in turn makes current flow in the coils of wire. This current corresponds to the unique grooves etched in a record, and can easily be amplified, making the music loud enough to enjoy.

The process by which records are made requires a substantial amount of heavy machinery, but if you are interested in what it involves, the video below (along with Part 2) walks through the process. I never would have realized what went into making a record player work if we hadn’t gotten one, but now that we have had to figure it out, I can appreciate the music even more.

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Nemo Lends a Helping Fin

Filed Under: Marine Science by keand — Leave a comment
March 18, 2013

I’ve wanted a pet clownfish for as long as I can remember, and when Disney/Pixar’s animated film Finding Nemo came out in 2003, it only made me want one more. Despite the fact that the movie features talking fish and sharks that wish to change their diets, filmmakers went to an astonishing extent to ensure the animation was as true to the habitat it depicted as possible–including the relationship between Marlin and Nemo, and their sea anemone home. As it turns out, keeping a clownfish as a pet is not an easy feat, as clownfish like Nemo rely on anemones in order to survive. As complex as the interaction between the clownfish and the anemone may be, and despite Finding Nemo’s attention to detail, scientists have recently discovered that there is in fact more to the relationship than was previously thought.

Nemo’s real life counterpart in an anemone.

Marine biologists have known for quite some time that the sea anemone functions as a protective home for clownfish. However, it was not until February of this year that a study was published explaining how clownfish can benefit their protectors as well. Clownfish are able to dwell in anemones, which are toxic to other fish, by coating themselves in mucus. Because the anemones secrete toxins, predators keep their distance, allowing the slow-swimming clownfish to survive.

(Source: http://blog.nativefoods.com/nativefoods/2010/08/oceans-alive.html)

Some anemones may look like flowers or strange sea plants, but they are actually animals too. The base of the sea anemone houses its mouth, which is surrounded by its toxic tentacles. Like other sea creatures, anemones need oxygen in the water in order to respire and  survive. During the day, plants in the ocean photosynthesize, taking in light and carbon dioxide from the atmosphere, and releasing oxygen into the water. This means that anemones have plenty of oxygen during daylight hours, but at night the oxygen levels in the water decrease. Researcher Joseph Szczebak, of Auburn University, along with his colleagues, was the first to consider how clownfish might assist their anemone homes in getting oxygen at night.

Sea anemones stun small fish with their tentacles before eating them.

In order to test his theory that perhaps clownfish might oxygenate sea anemones, like other sea creatures have been known to do, Szczebeck ventured to the Red Sea to observe the fish in their natural habitat. He measured the oxygen intake of clownfish and anemone pairs, and  found that they used the most oxygen when they were together. Curious about his discovery, Szczebeck set up an experimental tank. In the tank he placed a clownfish and sea anemone, and set up an infrared camera to record movement that took place. Szczebeck found that when the clownfish was able to make contact with the anemone, it became very active. The clownfish would swim and flip between the tentacles of the anemone, opening it up to take in more oxygen.

(Source: http://www.esu.edu/~milewski/intro_biol_two/lab_9_porifera_cnidaria/sea_anemone_diagr.html)

Oxygenated sea anemones are able to grow more quickly, which further helps the clownfish by giving it more space to live. It turns out that the symbiotic relationship between clownfish and anemone is what makes it so difficult to keep clownfish in aquariums. Sometimes the fish are not paired with the right kind of anemone host, which can shorten their lifespan. Needless to say, I probably wont be getting a clownfish of my own any time soon, but I definitely can’t wait for Finding Nemo 2.

(Source: http://www.aqua.org/explore/animals/clownfish)

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Scientific Sonnets

Filed Under: Science in the News by keand — Leave a comment
February 21, 2013

It’s safe to say that DNA is an important part of our daily lives. Not only does DNA code for our characteristics as humans, but it differentiates us from other species, and is frequently used to solve crimes. Despite it’s biological usefulness, you might be wondering what our genetic code has to do with Shakespeare and his sonnets. The answer may very well be the future of data storage.

It might sound as if it’s straight from the pages of a science fiction novel, but scientists have recently discovered a way to synthesize DNA encoded with information of all sorts–including all 154 of Shakespeare’s sonnets. Researcher Nick Goldman, of the European Bioinformatics Institute of Hinxton, England, is one of the leading experts in the field. As Goldman explains, DNA has the potential to replace hard drives and disks because of its long lifespan and durability. DNA can also store enormous amounts of data in a small space. In fact, Goldman estimates that all of the information in the world today–about one billion trillion bytes–would fit “in the back of your station wagon.”

Nick Goldman points to a segment of DNA storing approximately one billion megabytes of data.

(Source: http://earthsky.org/human-world/scientists-successfully-store-data-in-dna)

It’s a bit difficult to fathom at first, but the idea behind storing data in DNA is relatively simple. The secret lies in the double helix shape of the DNA molecule. While technology now allows us to store information in two-dimensional items like CDs and microchips, DNA is a tightly wound three-dimensional molecule, enabling the storage of more information in a compact space. The structure of DNA is also responsible for the synthetic process used to encode it with information. DNA is composed of two sets of base pairs: adenine (A) with thymine (T), and guanine (G) with cytosine (C). Each base is a nitrogen containing compound, and when a base bonds to its pair, it helps to hold the double helix of the DNA molecule together.

The structure of DNA is the key to its ability to store data.

In using DNA as a storage device, scientists like Nick Goldman have taken advantage of the A, T, and G, C base pairings. By representing the bases with ones and zeros, scientists have been able to use binary–the system responsible for data encoding in computers–within molecules of DNA. In order to convert between DNA code and binary, Goldman and his colleagues wrote software capable of doing so. Shakespeare’s sonnets, for example, were first represented in binary in a computer. The software then converted the binary into a series of A’s, T’s, G’s, and C’s, which could be made into a strand of DNA. (This is a diagram that makes it a little easier to visualize.)

(Source: http://science.howstuffworks.com/life/cellular-microscopic/dna1.htm)

Containing information in DNA doesn’t come without its problems however. With current technology, synthesizing and encoding information is extremely expensive, and therefore isn’t practical outside of a lab. Because it is so dense, DNA is also heavy, making large quantities somewhat difficult to transport. But, that’s not to say that there isn’t hope for this field of science. Given the pace at which technology is progressing, it’s probable that software and tools similar to those available to Nick Goldman will one day accessible to the public. Though the process isn’t perfect now, Goldman speculates that in as little as 10 years, it may be “economically viable.” The decreasing cost of DNA synthesis and the success of the project thus far are good indicators that scientists like Goldman are on to something. Before we know it, we may be storing much more than our genetic code in a double helix.

Nick Goldman was featured on NPR’s Science Friday last month. You can listen to his interview here.

 

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It’s a bird! It’s a plane! It’s a … flying squirrel?

Filed Under: Physics by keand — Leave a comment
February 7, 2013

People seem willing to do just about anything for an adrenaline rush these days, and perhaps the most recent and terrifying sport is BASE jumping, with a twist in the form of a flying squirrel suit. More commonly referred to as a wingsuit, this squirrel-shaped device enables jumpers to fly from cliffs or bridges or wherever they’d like, just by spreading their arms. If you’re thinking what I’m thinking, there is no way that this is a good idea. The popularity of the sport, however, suggests that people certainly disagree–2012 was not only an exciting year for the Wingsuit Flying World Championship, but also for the races held by the World Wingsuit League. The fans may be convinced, but the trend still concerns me, so I have decided to explore the world of wingsuits in the hope that I can understand what the phenomenon is really all about.

Since it is up to the suits to defy gravity and keep jumpers alive, I think I’ll start with the physics behind how the suits work. Most of us know that if a jumper forgot his wingsuit, he would accelerate towards the Earth, due to the force of gravity. This free fall would be similar to that of the apple that was rumored to hit Sir Isaac Newton on the head, but assuming our jumper is not falling from an apple tree, the end of his journey would likely be a bit less fortunate. In order for flight to work, there are several factors involved, each of which is addressed by how the wingsuit is made. The diagrams below provide quite a bit of detail, but only a few forces need to be discussed to understand the basics of wingsuit flying.


(Source: http://www.wingsuitup.com/design/4571983795)

First, lift is generated by the extensive and carefully designed surface area of the wingsuit. Because it increases the surface area of the human body, the wingsuit slows the fall of the jumper. By moving his or her arms, legs, or body, the jumper can change the surface area of the suit that is met by wind, therefore changing the amount of lift experienced. While lift works to combat the downward force of gravity, drag is also responsible for determining movement. Drag is a frictional force created when air moves over the surface of the suit, and since the jumper does not have engines or a jet pack (these devices would create another force called thrust), drag slows the jumper’s forward motion. Taking these forces into account, technically wingsuit BASE jumping is more gliding than actual flying, but flying just sounds more exciting–what fun would it be if we called them “gliding squirrels”?

Wingsuit design has come a long way since the start of the extreme sport. Making use of materials like wood and metal, early wingsuit fliers saw an extremely high fatality rate. The concept of the modern wingsuit did not come about until the 1990′s, when skydiver Patrick De Gayardon designed a suit with a wing under each arm, and a third between the legs. Unfortunately, De Gayardon was killed when he experienced a suit malfunction on a dive, but his ideas were quickly taken up by fellow fliers. Today, wingsuits are made to provide the maximum surface area possible, without greatly restricting the ability of the jumper to move. A wingsuit flier learns to move his arms and legs to turn, tuck in his head to go farther and faster, and push against the wind to enable longer flight with more lift.

Even these squirrel-like daredevils know that each flight must come to an end, and preferably a safe one. In order to land without crashing, wingsuit fliers have parachutes built into their suits. When they reach the proper altitude, they deploy their parachutes in order to slow their descent to Earth. Without a parachute, slowing down enough to land would be very difficult, but that doesn’t mean that people haven’t tried! In 2012, Gary Connery was the first to land successfully without a parachute, guiding his dive to land in a massive pile of cardboard boxes. If I had to guess, I’d say the future of wingsuit flying will focus on new ways to make safe landings–mainly without parachutes.

In my exploration of wingsuit flying, I have discovered that this sport is considered to be extreme for a reason. I know I won’t be trying it any time soon! Dive footage can be pretty amazing and unique though, and I encourage you to check out this video if you want to see just how extreme wingsuit fliers can be!

YouTube Preview Image

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