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Why ‘Licking Your Wounds’ Works

Posted on July 23, 2008  Comments (3)

Why ‘Licking Your Wounds’ Actually Works

scientists found that histatin, a small protein in saliva previously only believed to kill bacteria was responsible for the healing.

To come to this conclusion, the researchers used epithelial cells that line the inner cheek, and cultured in dishes until the surfaces were completely covered with cells. Then they made an artificial wound in the cell layer in each dish, by scratching a small piece of the cells away.

In one dish, cells were bathed in an isotonic fluid without any additions. In the other dish, cells were bathed in human saliva. After 16 hours the scientists noticed that the saliva treated “wound” was almost completely closed. In the dish with the untreated “wound,” a substantial part of the “wound” was still open. This proved that human saliva contains a factor which accelerates wound closure of oral cells.

Because saliva is a complex liquid with many components, the next step was to identify which component was responsible for wound healing. Using various techniques the researchers split the saliva into its individual components, tested each in their wound model, and finally determined that histatin was responsible.

YouTube Access Denied

Posted on February 25, 2008  Comments (4)

Millions of users around the globe could not access YouTube for a couple hours yesterday. Why?

Well to understand, we need to start with how you normally connect to a web site. You click on a link to youtube.com. Your ISP looks up the internet address for youtube.com by looking at internet routing tables. Each domain has a name server that provides the IP address for where it should be found (for example, an IP address that shows youtube.com is 208.65.153.238).

Well what happened in this case is Pakistan decided to prevent anyone in Pakistan from accessing YouTube because the government didn’t like some video. The way Pakistan decided to accomplish this was to update their routing table to just direct all traffic that was meant to go to YouTube to a phony address which would then return nothing.

Why did many outside of Pakistan lose access to YouTube? Well their version of the routing table leaked out of Pakistan through PCCW (large internet provider), Then other internet providers adopted the incorrect information, until many around the globe were being directed to the wrong place.

You might find it amazing the routing system could allow such a thing to happen – it doesn’t seem very secure. You are right, that it doesn’t seem very sensible. When the internet was created some protocols were established that made sense then but don’t necessarily make sense for what the internet has become.

The problem was fixed when Google’s YouTube engineers contacted PCCW to inform them of the problem and have them correct it. I think if it was my site instead, I would have had difficulty figure out what was going on :-) Once PCCW corrected their routing tables the fixed flowed through the system and everyone was able to see the great stuff like Marissa Mayer discussing Innovation at Google.

I would imagine Internet2 (well on its way to a computer near you) and IPv6 will take not be so venerable to such a mistake.

Related: Insecure routing redirects YouTube to Pakistan – YouTube outage blamed on Pakistan – YouTube Censorship Sheds Light on Internet Trust – The Web is 15 Years Old – Internet Undersea Cables – Harvard Course: Understanding Computers and the Internet – Net Neutrality – The Next Generation Internet – The Journey of Internet Packets – mistake proofing (the opposite of the current setup)

Scientists Search for Clues To Bee Mystery

Posted on February 24, 2008  Comments (5)

Honey Bees Give Clues on Virus Spread by Carl Zimmer

Now, as farmers wait anxiously to see if the honeybees will suffer again this spring, the true cause of CCD remains murky. Skeptics have raised many reasons to doubt that Australian viruses are to blame. In Australia, bees that get Israeli acute paralytic virus don’t get sick, and the country has had no reports of CCD. And in places where honeybee colonies are collapsing — Greece, Poland, Spain — there are no imported Australian bees. These are not the sort of patterns you’d expect, the skeptics say, if Australian viruses were killing American bees.
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Whether scientists look inside a honeybee or look at the entire biosphere, nature is proving to be awesomely intricate. In the oceans and the soil, metagenomics is revealing millions of different kinds of microbes, with an almost inconceivable diversity of viruses shuttling between them, carrying genes from host to host. But we have almost no idea how these menageries work together, either in the biosphere or inside a host like a honeybee — or a human. Many of the microbes that metagenomics is revealing are entirely new to science. As genetic databases fill with DNA sequences from millions of new species, our scientific wisdom lags far behind.

How true. Watching as scientists try to work out what is going on with Colony Collapse Disorder is a great lesson in how scientists search for answers. As I stated earlier much of science is not about simple obvious truths but a search through confusing signs to try and determine what is going on. Answering why, is not always so easy as it appears when someone has already found the answer and posted it online.

Related: Virus Found to be One Likely Factor in Bee Colony Collapse Disorder – Bee Colony Collapse Disorder – More on Disappearing Honeybees – most Carl Zimmer related posts

Science Explains: Flame Color

Posted on February 18, 2008  Comments (4)

Have you ever wondered why some flames are yellow, while others are blue? Growing up, I was always told that it was a matter of temperature, that hot flames were blue and cooler flames were yellow. While there is a temperature difference, that difference is a “symptom” of what is going on, not the cause of the color difference.
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Does that mean that there is solid stuff inside the candle flame? Let’s find out. Light the candle and be sure it is steady and won’t fall over. Hold the bottom of the plate in the candle flame for a few seconds. When you remove the plate, it has turned black!!! Don’t worry. You have not ruined it. Let it cool for a minute. Remember, it is HOT! Once it has cooled, rub your finger over the black spot. The black rubs off.

Related: Science Explained: What The Heck is a Virus? – Why is the Sky Blue? – Frozen Images

Science Explained: What The Heck is a Virus?

Posted on December 26, 2007  Comments (5)

What The Heck is a Virus?

A virus is not strictly alive.. nor is it strictly dead… A virus has some fundamental information (genes made of DNA or RNA) which allows it to make copies of itself. However, the virus must be inside a living cell of some kind before the information can be used. In fact, the information won’t be made available unless the virus enters a living cell. It is this entrance of a virus into a cell which is called a viral infection. Too, the virus is very, very small relative to the size of a living cell. Therefore, the information the virus can carry is actually not enough to allow it to make copies (replicate). The virus uses the cell’s machinery and some of the cell’s enzymes to generate virus parts which are later assembled into thousands of new, mature, infectious virus which can leave the cell to infect other cells.

Related: What Are Viruses? – Science Summary: Photosynthesis – Amazing Science: Retroviruses – Using Bacteria to Carry Nanoparticles Into Cells

Why is the Sky Blue?

Posted on November 26, 2007  Comments (5)

Here is a a nice post explaining why we see blue when we look at the sky, Why Is The Sky Blue?:

Most of the atmospheric gases are transparent to visible light. They don’t filter the Sun’s light and make it yellow, as a yellow filter would. Besides, if colored gases made the Sun appear yellow, where does the blue come from? The part of the atmosphere that changes the Sun’s light is the molecules and tiny particles that are floating in it.

There are particles of water–tiny droplets too small to be seen as clouds. There are particles of organic material–smog or haze, condensed from volatile organic chemicals that have gotten into the air. There are particles of sulfuric acid from volcanoes and power plants. There are molecules of gases in the atmosphere.

These tiny particles, much smaller than the wavelengths of sunlight, scatter the sunlight as photons from the Sun interact with the particles. This is called Rayleigh scattering after the British physicist who described how it works. (Larger particles, like the water droplets in clouds, are closer to the wavelengths of sunlight, and they scatter it differently. This is why clouds are not blue.)

Science explained – quick overviews of scientific concepts: How Does That Happen? Science Provides the Answer – Incredible Insects – 10 Science Facts You Should Know – What Everyone Should Learn – Science Summary: Photosynthesis – String Theory in 1 page – How do antibiotics kill bacteria?

Why do We Sleep?

Posted on May 1, 2007  Comments (4)

Study puts us one step closer to understanding the purpose of sleep:

Sleep remains one of the big mysteries in biology. All animals sleep, and people who are deprived of sleep suffer physically, emotionally and intellectually. But nobody knows how sleep restores the brain.
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Although an electronic power-napper sounds like a product whose time has come, Tononi is chasing a larger quarry: learning why sleep is necessary in the first place. If all animals sleep, he says, it must play a critical role in survival, but that role remains elusive.

Based on the fact that sleep seems to “consolidate” memories, many neuroscientists believe that sleeping lets us rehearse the day’s events.

Tononi agrees that sleep improves memory, but he thinks this happens through a different process, one that involves a reduction in brain overload. During sleep, he suggests, the synapses (connections between nerve cells) that were formed by the day’s learning can relax a little.

Sarah, aged 3, Learns About Soap

Posted on January 4, 2007  Comments (8)

A Dialogue with Sarah, aged 3: in which it is shown that if your dad is a chemistry professor, asking “why” can be dangerous by Stephen McNeil.

DAD: Why does the soap grab the dirt?
SARAH: Yes.
DAD: Because soap is a surfactant.
SARAH: Why?
DAD: Why is soap a surfactant?
SARAH: Yes.
DAD: That is an EXCELLENT question. Soap is a surfactant because it forms water-soluble micelles that trap the otherwise insoluble dirt and oil particles.

Great. I remember such discussions with Dad (Chemical Engineering professor). The only danger I saw was him getting tied of -why? (when I was older). And sometimes giving me answers the teacher didn’t like (a way of doing math problems that wasn’t the way my teacher was teaching).

Related: Illusion of Explanatory Depth – Excellence in K-12 Mathematics and Science Teaching – What Kids can Learn – Science for Kids
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Illusion of Explanatory Depth

Posted on November 17, 2006  Comments (8)

The “Illusion of Explanatory Depth”: How Much Do We Know About What We Know?

Often (more often than I’d like to admit), my son (Darth Vader over there on the left) will ask me a question about how something works, or why something happens the way it does, and I’ll begin to answer, initially confident in my knowledge, only to discover that I’m entirely clueless. I’m then embarrassed by my ignorance of my own ignorance.
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I wouldn’t be surprised, however, if it turns out that the illusion of explanatory depth leads many researchers down the wrong path, because they think they understand something that lies outside of their expertise when they don’t.

Great stuff. It took me a lot longer to stop asking why, why, why than most kids. I only gave up after years of repeated obvious clues that I was not suppose to ask why (once I aged past 5 or 8 or something – I actually have no idea when it is no longer desired). But most days I, curious cat, want to ask how does that work, why do we do that, why can’t we… I just stop myself. But it does mean I asked myself and realized I don’t really know. So I am at least more aware how little I really know, I think I am anyway.

The internet is a great thing. Google doesn’t mind if you ask as many questions as you want.

Related: Theory of Knowledge – Feed your Newborn Neurons

Energy Efficiency of Digestion

Posted on November 1, 2006  Comments (3)

Why is Fecal Matter Brown?

The complex digestion process ensures that almost no useful energy goes unused. The average bowel movement is three parts water to one part solid matter. Bacteria make up 30 percent of the solid stuff. The same goes for indigestible foods like cellulose and extra fiber. The remaining 40 percent contains various inorganic wastes, fats and used-up body substances like red blood cells

Scientists Examine 100 Trillion Microbes in Human Feces:

Aiding the large intestine in this task are trillions of microbes that reside in the gut, where they help digest foods we would otherwise have to avoid. In this way the bugs contribute to our overall health.

Some of these tiny settlers are with us from birth, imparted from our mothers, while others gradually colonize our bodies as we grow. This microbial community is as diverse as any found in Earth’s seas or soils, numbering up to 100 trillion individuals and representing more than 1,000 different species.

Spider Thread

Posted on August 20, 2006  Comments (3)

Spider hanging by its thread

Why a spider hanging from a thread does not rotate

The extraordinary properties of spider’s thread are like a blessing for researchers working on polymers. However, the amazing twisting properties it displays are still not very well understood. How can one explain the fact that a spider suspended by a thread remains completely motionless, instead of rotating like a climber does at the end of a rope?
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Spider’s thread, on the other hand, is very efficient at absorbing oscillations, regardless of air resistance, and retains its twisting properties during the experiments. It also returns to its exact original shape. Certain alloys, such as Nitinol, possess similar properties but must be heated to 90° to return to their original shape.

The amazing properties of spider’s thread have been known for several years: its ductility, strength and hardness surpass those of the most complex synthetics fibers

See more blog posts on life science, biology, etc. and more posts of interest to students and everyone interesting in learning about science.

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