Friday, 27 September 2013

Sketchy Fact #8: Primordial Soup de Jour

If you could go back through time at a rate of one year per second, it would take you more than 115 years to reach the dawn of life on Earth around 3.8 billion years ago. You would be disappointed with what you found.

Wednesday, 25 September 2013

Beneficial Bacteria – The Biome in Your Belly

Most people think of bacteria as something to be avoided. We steer clear of shaking hands with a sick co-worker, we filter and treat our water, and some of us even carry around little bottles of hand sanitizer. The war on microbes is both ubiquitous and illusory.  You can certainly take measures to avoid harmful germs but you will never be able to completely rid yourself of bacteria, nor would you want to.

Mary Roach said it best in her newest page-turner Gulp:Adventures on the Alimentary Canal, “Like people, bacteria are good or bad not so much by nature as by circumstance.” You have loads of bacteria in your ears, mouth, nose, throat, and gut and each of them either serves a useful function or doesn’t cause you any harm at all. That is unless you put them somewhere they aren’t supposed to be. For example, take a few Streptococcus bacteria from your throat (where the worst they will cause is a sore throat) and put them in your bloodstream and you will swiftly find yourself dying from necrotizing fasciitis, AKA flesh eating disease.

One place where bacteria seem to be the body’s greatest ally is in your colon. They aid in digestion, produce vital nutrients, and even help kill invader bacteria. Scientists are only now really beginning to appreciate the full-fledged ecosystem that exists inside your large intestine. And when I say “your” I mean it. Each person is host to their own custom mix of bacteria. It’s easy to think of them as parasites living off of your digestive tract, but in a very real sense they help make you, you.

Unfortunately, being you is not always a thrill. Even those of us with strong stomachs will get laid up with gas, bloating, or diarrhea at some point, no matter how careful we are about our health. In the worst cases, we can open the gate to evil bacteria that can produce chronic problems by overpowering your custom-built intestinal police force and hijacking your innards to cause you harm.

One of the worst examples is the bacterial infection C. difficile. This bacteria, which is most prevalent in hospitals, can set up shop in your colon and cause you all kinds of problems. The most embarrassing and life altering can be a persistent inability to… how can I put this?… trust a fart. The standard treatment is a course of anti-biotics, but for every course of treatment that doesn’t completely wipe them out, your chance of relapse doubles.

When all else fails there is one treatment that is almost guaranteed to work. The problem is, it is equal parts captivating and disgusting. The idea is to take the bacterial ecosystem from someone else’s colon and grow a replica in the infected person. It all sounds very scientific until you realize that it is called fecal bacteriotherapy and you find out how it is achieved…

First, the patient is given a run of powerful antibiotics to kill pretty much every bacterium in their colon. Next, a donor (anyone with a healthy gut) is asked to (I am trying to choose my words carefully here) collect a sample of their own detritus. The sample is then blended (yes, with a blender) and administered into the sick person’s large intestine. It may sound gross (once you figure out what I’m talking about) but in 93% of cases it works. The bacteria from the healthy person colonize the troublesome colon and health is restored in a matter of hours. A welcome relief for a person who may have previously been unable to leave their own home for fear of an embarrassing intestinal event.

Your body is an amazing partnership of organs and organisms. Finding and maintaining a healthy balance is the key to living a long and enjoyable life. But even if you’re not preoccupied with increasing longevity or running a marathon, you have one powerful incentive to try and maintain a fit digestive tract: Nobody wants a poop transplant.

Friday, 20 September 2013

Sketchy Fact #7 - Large Mammals That Get Called into Existence

The Blue Whale is the biggest animal to have ever lived on Earth, that humans are aware of. It weighs 70 tonnes more than the biggest dinosaur ever discovered – Agrentinosaurus (170 tonnes and 100 tonnes respectively).

Wednesday, 18 September 2013

Forest Bathing: Not Just for Homeless People, Anymore

What have trees ever done for anybody, anyway? Sure they help us build ships, tables, paper and a bunch of other things that make civilization possible, but that stuff all comes from chopping them down. In today’s increasingly ‘green’ culture, you always hear about saving the rainforest and protecting nature in general, but does leaving trees standing actually benefit any person?

The answer is a resounding and irrefutable “Yes.” Quite obviously they help improve the air quality and the recycling of oxygen to help us breathe. As an added plus, they are also quite nice to look at. However, it also turns out that they may be helping beyond what is obvious.

Shinrin-yoku – literally “Forest Bathing” – is a Japanese concept introduced by the nation’s Forest Agency in 1982 as a means to promote healthy and active lifestyles. Though they didn’t have the science to support it at the time, the people behind the initiative felt that there must be some benefit to spending time in nature, because quite frankly it seemed too pleasant not to be good for you.

In recent years Dr. Qing Li – associate professor in the Department of Hygiene and Public Health at Tokyo’s Nippon Medical School – has begun to provide the hard proof to back forest bathing.

Researchers have known for quite a while that time spent in nature helps us to relax. When we watch the waves roll in off the ocean or take in a big, spicy lung-full of mountain air, the pressures of modern life seem to wash away. Psychological research has shown that people who spend time in nature often perform better on mental tasks than those who try to relax in the city. They are also rated higher on measures of basic effectiveness.

Dr. Li’s work has gone one step further and measured actual responses the body makes to kicking back in the woods. Participants in his studies – though some might prefer to call them vacations – have demonstrated reduced stress hormones and improved stability in their heart rate. They were even more reactive to changes in their environment.

This is all well and good, but there is one result from forest bathing research that almost seems too amazing to believe. Dr. Li and his students have observed enhanced immune system activity and greater numbers of cancer-fighting cells in their forest-bound guinea pigs.

That almost seems to go too far. You had me with lower stress and better attention, Dr. Li; but a walk in the woods as cancer treatment? What do you take me for?

Once again, cue Qing Li with hard science to support his claims. Leaving the woods and heading into the lab, Dr. Li has shown that phytoncides, which are chemicals produced and emitted into the air by trees through their wood oils, can induce human “Natural Killer” cell activity. Natural killer cells are far better than they sound. The killing they do is of cancer. It’s like Terminator 2.

This work has been supported by other researchers as well. In a study of cancer-laden lab rats, the subjects living in a care-free phytoncide-rich environment had slower tumor growth and their tumors were 40% smaller compared to their regular lab compatriots. 

A good scientist will never tell you that they have proven something beyond all doubt, but sometimes the evidence speaks for itself. Next time you have a choice between a jog on the treadmill or a run through the forest, you might want to opt for the latter. Not only will you feel less stressed and more effective, but  your cancer might not grow as fast, either. 

Friday, 13 September 2013

Sketchy Fact #6: Mammoth Pyramid Scheme

The last wooly mammoth died in about 1700 BC, about 850 years after the Great Pyramid of Giza was completed. It was pygmy mammoth that was about as tall as an average man (1.71 m) and lived on the Channel Islands in the Bering Sea.

Wednesday, 11 September 2013

Adam and Eve – The snake-free version that actually happened

Every so often in science you come across a fact that is at the same time strikingly obvious and obviously striking. The most memorable example I can think of in my own life was the day that I learned that Adam and Eve were real people.

Before we let our imaginations get the best of us, let’s stop and recognize that I am not talking about the biblical Adam and Eve. It doesn’t take a brilliant mind to see that two people with three sons would have a hard time spawning the rest of humanity without some serious and deleterious in-breeding going on. No, I am talking about the two people known to science as Y-chromosomal Adam and Mitochondrial Eve. Although it is all but certain that they never crossed paths, these two people are literally the direct ancestors of every person alive today.

In a way, it is common sense. Since every living thing on Earth shares a common ancestor (if you go back far enough in time) there must be a point at which all human bloodlines converge. Yet, this is one of those cases where common sense can still knock you off your feet.

To really understand what I’m talking about, you need to understand something about genetics (don’t worry, it’s a simple idea). Basically when a man and a woman do the horizontal hustle and produce a baby, it is largely a product of both of their DNA. Genetic material from the man mixes from that of the woman and gets recombined to make a new genetic code that is similar to but different from the genetic code of each parent. That is how most genetic change happens, but it isn’t the only way.

The alternative is mutation. As we have seen in previous articles (mitosis, epigenetics, and radioactivity) mutation can happen as a result of things we are exposed to (radiation, diet, etc.) but it can also happen naturally. Natural mutation happens at a fairly steady rate that has been estimated at 0.00000003 mutations per generation.

Y-chromosomal Adam, as the name suggests, is the man from whom all living men have inherited their Y-chromosomes. Since only men carry Y-chromosomes, they are only passed on by fathers, grandfathers, great-grandfathers etc. and they are not influenced by DNA from mothers. As a result, the only way the Y chromosome ever changes is through mutation.

This is not just a logical idea; it is something scientists have demonstrated. By looking at the Y-chromosomes of men from all over the world and counting the number of mutations, researchers have estimated that “Adam” probably lived sometime around 100,000 years ago in Africa. He was probably more concerned with outrunning hyenas than fathering 3.5 billion sons, but somehow he managed to pull it off.

We can use a similar idea to determine how long ago the mother of all humans lived, too. Instead of using Y-chromosomes, scientists have looked at mitochondrial DNA. Mitochondrial DNA is a separate set of DNA that doesn’t really belong to you but is found in every one of your cells. You see, every cell contains organisms called mitochondria which convert food into energy. The weird thing is, billions of years ago, mitochondria were totally separate and independent from cells. At some point, they made a deal with the organisms that would become cells where they would live inside them and provide energy to their hosts. They never fully integrated though, and to this day mitochondria still replicate on their own schedule and have their own DNA.

Sperm don’t have mitochondria, but eggs do. The upshot is that, whether you are a man or a woman, you got all your mitochondria from your mom. Similar to Y-chromosomes, this DNA only changes through mutation and, as a result, we can trace it back to the point where all human bloodlines converge. It turns out Mitochondrial Eve lived about 200,000 years ago, also in Africa.

These were the numbers that were generally accepted until a couple weeks ago. It turns out that two teams of researchers working independently of one another have revised the age estimates of the mother and father of humanity. Their work suggests that Adam lived between 120,000 and 200,000 years ago and Eve lived sometime between 99,000 and 200,000 years ago.

Look at those numbers again. It is pretty amazing. The ranges now overlap. That means that the two people at the root of all human DNA might have even been alive at the same time on the same continent. Admittedly, it isn’t very likely but the possibility is amazingly cool. At some point there may have been two people who never knew each other and never spoke to one another and probably were never within a few hundred miles of one another; but through a brilliant streak of genetic luck, they produced every single one of us. Chew on that for a while, cousin.

Friday, 6 September 2013

Sketchy Fact #5: Atomic Baseball

Atoms are 99.999% empty space. If you blew one up to the size of a baseball stadium, the nucleus would be the size of a fly on the pitcher’s mound and the electrons would be buzzing in the parking lot.

(It's impossible to occupy the same state)

Wednesday, 4 September 2013

Solar Power: Not Just for Hippies, Anymore

Wouldn’t it be great if somebody invented a free source of power that anyone could use to power their lives? Ideally it would be an entity of pure energy positioned in the sky so we could all make use of it. If you made it big enough and powerful enough you could even put it 150,000,000 km’s away.

Fortunately for humans, the laws of physics have done the job for us and the bright, hot, skin bronzing power plant we call the Sun has been powering our planet since its fusion switch was first flipped on around 5 billion years ago. Unfortunately, we humans really suck at taking advantage of it.

Give a plant a steady stream of sunlight and it will work wonders. Plants can take the particles of light given off by the sun (photons) and directly use them as food. Photons power plant growth as well as photosynthesis, which is something all of us air-breathers should be thankful for. Since every food chain on the planet begins with plants, it is easy to see how the whole notion of “food” is based on transferring the sun’s energy from one body to another. Compared to plants, we humans are solar sissies.

The trouble with people is that having enough energy to power our bodies just doesn’t cut it anymore. We also need to power our houses, cars, computers, iPods, robot vacuums, dancing Santa’s and all the other things that modern life would be impossible without. It turns out that coaxing the sun into juicing our electronics for us is trickier than it might at first seem.

Conventional solar cells do a remarkably bad job turning photons into useful energy. Your average solar panel has an efficiency of about 20% - meaning that only 20% of the energy input (light) is converted into useful output. The way they work is complicated but basically you take some semi-conductive material (usually silicon (Si)), form it into a sheet, wire it up, and place it in the sun. Photons excite the electrons in the material, knocking them loose and sending them off to do useful things. To get electrons to do what you want, you need to create a current for them to flow along. 

Where you will run into trouble is primarily in 2 places:  the nature of light itself, and willfully moving electrons. As anyone who has ever seen a rainbow can tell, light comes in different wavelengths – each represented by a different colour. Different wavelengths have different amounts of energy. Only a small proportion of the Sun’s light has the exact amount of energy needed to excite electrons in a given material (ex. silicon). If a photon doesn’t have enough energy, it won’t knock any electrons loose. If it has too much energy, it uses just the amount is needs to nudge an electron and the rest is wasted. In the end, you lose about 70% of the possible energy in a beam of light to this problem. Even when you manage to get your electrons going and try to move them from one place to another, you lose energy if the distance is too far or if they are flowing through something that isn’t a very good conductor.

The upshot of these limitations is that you usually need a whole lot of solar panels if you want to power anything beyond a calculator with reliability. Recently, though, there has been some cause for optimism. Researchers at Caltech led by Dr. Harry A.Atwater have created a commercially viable solar panel that is up to 50% efficient. That still may not sound great, but it represents a massive leap forward in solar energy. 

Dr. Atwater and his team, working under the company name Alta Devices, have done away with silicon and instead build their cells from gallium arsenide (GaAs). The researchers argue that this material builds purer crystals than silicon (increasing efficiency), absorbs more photons, and produces more energy than conventional solar panels. On top of that, they have engineered their devices to recycle unused photons and be 1/40 the thickness of a human hair, making them doublely useful and ridiculously flexible. A few other innovations offer promise in creating more efficient solar cells including organic polymers and dye-sensitized materials that can absorb more photons.

Arun Das, PhD student at the University of Waterloo’s Autonomous Vehicles Lab, told Sketchy Science that, “low weight solar cells are very exciting. We would no longer be constrained to using [solar panels] on rooftops and solar farms. We could soon see solar cells as a viable option for charging our smartphones, extending the range of electric cars, and powering small unmanned rescue drones in disaster scenarios.”

As you can imagine, the impact all this would have on fossil fuel emissions would be immense. But that pales in comparison to the benefits of being able to watch The Biggest Loser in the middle of the woods.