Author Archives: curiouscat

Why does orange juice taste so bad after brushing your teeth?

Why does orange juice taste so bad after brushing your teeth? Ok, those that have never experienced this go try it. You will discover why I still remember learning that orange juice and toothpaste didn’t mix when I was a kid. Isn’t it great that I can stumble across answers to questions I had forgotten I asked 🙂

David Cannell is the scientific spokesperson for Questacon, “It’s because of a certain ingredient in toothpaste called sodium laurel sulfate. It actually blocks sweet sensors. All the other taste bud cells in your mouth are firing away nicely, but the receptors which pick up the sweet sensors are not working anymore. Not only does it block the sweet sensors, it enhances the sour and bitter, so you get this massive influx of sour and bitter taste coming through the mouth.”

David says tastebuds are a very interesting part of the body, “They’re the little bumps on the top of your tongue. They look like a tiny onion, if you look at it with a high powered microscope. Each tastebud, which we have about ten thousand of, has about fifty different taste cells.”

Just imagine what we will find with the better internet that China is building?

Lab on a Chip Blood Tests

Portable ‘lab on a chip’ could speed blood tests:

Within the lab on a chip, biological fluids such as blood are pumped through channels about 10 microns, or millionths of a meter, wide. (A red blood cell is about 8 microns in diameter.) Each channel has its own pumps, which direct the fluids to certain areas of the chip so they can be tested for the presence of specific molecules.

Until now, scientists have been limited to two approaches to designing labs on a chip, neither of which offer portability. The first is to mechanically force fluid through microchannels, but this requires bulky external plumbing and scales poorly with miniaturization.

The second approach is capillary electro-osmosis, where flow is driven by an electric field across the chip. Current electro-osmotic pumps require more than 100 volts of electricity, but the MIT researchers have now developed a micropump which requires only battery power (a few volts) to achieve similar flow speeds and also provides a greater degree of flow control.

Natural History Museum Wildlife Photos of 2006

photo of ghost frog

Shell Wildlife Photographer of the Year online photo gallery, Natural History Museum, London.

Ghost glass frogs are still relatively widespread, but are difficult to find.
…
Ghost glass frogs get their name from the transparent skin on their bellies through which you can see their organs and even their circulating blood.

Antibiotic Research

anti-microbial ‘grammar’ posits new language of healing

“In the last 40 years, there have been only two new classes of antibiotic drugs discovered and brought to the market,” said graduate student Christopher Loose, lead author of a paper on the work that appears in the Oct. 19 issue of Nature. “There is an incredible need to come up with new medicines.”
…
focusing their attention on antimicrobial peptides, or short strings of amino acids. Such peptides are naturally found in multicellular organisms, where they play a role in defense against infectious bacteria.

See previous post on the paucity of new antibiotic discoveries

More Great Webcasts: Nanotech and more

ScienceLive video archive from Cambridge University Science Productions. Videos include:

Viruses as nanomachines by Peter Stockley
Powering nanodevices with biomolecular motors by Amir Khan
Ice Cream, Chocolate, and Einstein by Chris Clarke
Communicating Science by Brian Trench and David Dickson
So many experiments, live in the studio! by Paul McCrory

Great stuff, another example of universities providing open access content 🙂

Complete Work of Charles Darwin Online

Complete Work of Charles Darwin Online – The University of Cambridge has done a much better job of use the web effectively than some others: Classic Botanical Illustrations Presented Poorly. The site includes 50,000 pages and 40,000 images (publications and handwritten manuscripts), including, of course, Origin of Species. Fantastic stuff.

Life Untouched by the Sun

Gold mine holds life untouched by the Sun

The first known organisms that live totally independently of the sun have been discovered deep in a South African gold mine.

The bacteria exist without the benefit of photosynthesis by harvesting the energy of natural radioactivity to create food for themselves. Similar life forms may exist on other planets, experts speculate.

The bacteria live in ancient water trapped in a crack in basalt rock, 3 to 4 kilometres down. Scientists from Princeton University in New Jersey, US, and colleagues analysed water from the fissure after it was penetrated by a narrow exploratory shaft in the Mponeng gold mine near Johannesburg, South Africa. The shaft was then closed.

I must say I was confused why this was seen as the “first” such life.

Other sulphate-eating bacteria have been found in ocean sediments, volcanoes and oil deposits. But all have either received some chemicals produced by photosynthesis, or it has not been clear whether they were trapped and dying, or flourishing.

I am still not sure the “first” claim is really accurate (from NASA site in 2001), but nevertheless this is another interesting case of extremophiles.

Related: Bacteria Living in Glacier

String Theory is Not Dead

The Universe on a String by Brian Greene (author of The The Elegant Universe).

String theory offers a new perspective on matter’s fundamental constituents. Once viewed as point-like dots of virtually no size, particles in string theory are minuscule, vibrating, string-like filaments. And much as different vibrations of a violin string produce different musical notes, different vibrations of the theory’s strings produce different kinds of particles. An electron is a tiny string vibrating in one pattern, a quark is a string vibrating in a different pattern. Particles like the photon that convey nature’s forces in the quantum realm are strings vibrating in yet other patterns.
…
Without the exact equations, our ability to describe these attributes with precision is limited, but the theory gives enough direction for the Large Hadron Collider, a gigantic particle accelerator now being built in Geneva and scheduled to begin full operation in 2008, to search for supporting evidence by the end of the decade.

Science and Engineering Internships for Summer 2007

Office of Naval Research Science & Engineering Apprentice Program (SEAP)

SEAP provides competitive research internships to approximately 250 high school students each year. Participating students spend eight weeks during the summer doing research at Department of Navy laboratories.

Requirements:

* High school students who have completed at least Grade 9. A graduating senior is eligible to apply.
* Must be 16 years of age for most laboratories
* Applicants must be US citizens and participation by Permanent Resident Aliens is limited.
* The application deadline is February 17, 2006.
Continue reading →

Engineering Harry Potter’s Invisibility Cloak

Disappear into thin air? Scientists take step toward invisibility by Peter N. Spotts:

Flip a switch and make something disappear? It’s been the stuff of science fiction for decades. Now, two Duke University scientists and their colleagues have built the world’s first device to render an object invisible.

At least, it’s invisible to microwaves.

But researchers say the work demonstrates that, in principle, objects could be made to disappear from radar, cameras, and other detection devices. The trick? A new class of engineered substances called metamaterials.

Update: more info from Duke, including a video.