Category Archives: Science

Secrets of Spider Silk’s Strength

The strength of a biological material like spider silk lies in the specific geometric configuration of structural proteins, which have small clusters of weak hydrogen bonds that work cooperatively to resist force and dissipate energy, researchers in Civil and Environmental Engineering have revealed.

This structure makes the lightweight natural material as strong as steel, even though the “glue” of hydrogen bonds that hold spider silk together at the molecular level is 100 to 1,000 times weaker than the powerful glue of steel’s metallic bonds or even Kevlar’s covalent bonds.
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“Using only one or two hydrogen bonds in building a protein provides no or very little mechanical resistance, because the bonds are very weak and break almost without provocation,” said Buehler, the Esther and Harold E. Edgerton Assistant Professor in the Department of Civil and Environmental Engineering. “But using three or four bonds leads to a resistance that actually exceeds that of many metals. Using more than four bonds leads to a much-reduced resistance. The strength is maximized at three or four bonds.”

Mutation Rate and Evolution

Stop the Mutants! by Olivia Judson

I’m going to wave a magic wand and reduce the mutation rate to zero, instantly, in all species, and forever. Then I’m going to watch to see how long it takes for evolution to stop.
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Actually stopping mutations is a physical impossibility – hence the need for a magic wand. But if they were to stop, so would raw invention. But evolution would not. Not for a long time.
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And sometimes natural selection actively promotes the persistence of genetic variation. This can happen when there’s an advantage to having genes that are rare. Among guppies, for example, males with rare color patterns are much more likely to survive than those with common color patterns, presumably because predators get good at spotting the patterns they encounter often. In such situations, the rare type does well, begins to become common – and then becomes the victim of its own success and starts to do badly. In situations like this, the frequencies of different genes can rise and fall, cycling indefinitely.
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Among lifestyles that promote genetic diversity, far and away the most important is sex. Sex shuffles up genes, continually producing new gene combinations. (An important difference between sex and mutation is that sex can only create genetic novelty if it already exists in the population. If everyone is genetically identical, sex will have no effect.) Sex also – and this is important – decouples the fates of genes from one another.

2008 Intel Science Talent Search

When Shivani Sud was six years old, one of her immediate family members was diagnosed with a brain tumor. Inspired by the doctors who helped her loved one recover, Shivani set her sights on a career in medicine.

Fast forward to Intel STS 2008, where the 17-year-old senior from Durham, North Carolina, presented research focused on identifying stage II colon cancer patients at high risk for recurrence and the best therapeutic agents for treating their tumors. Whereas the standard method of characterizing tumors relies on visual information (such as size, degree
of metastasis, and microscopic structure), Shivani developed a “50-gene model” which uses gene expression to link multiple genetic events that characterize various tumor types to more accurately predict the recurrence of colon cancer. Additionally, Shivani’s model can be used to identify drugs that may be most effective in treating each patient.

In 2006 she attended the Davidson Institute, summer program at Davidson College and received the Davidson Fellows Scholarship.

And now I can segue to the Davidson Wildcats victories in the NCAA basketball tournament last weekend (I graduated from Davidson, by the way, and grew up in Madison). Davidson will play the Wisconsin Badgers on Friday. My picks are doing pretty well.

Science Serving Society – Speech Australian Minister for Innovation

Kim Carr, Minister for Innovation, Australia, speech to the National Press Club of Australia: Science meets Parliament

When societies invest in science, they are investing in their own future. They are entitled to expect a fair return on that investment.

They’re entitled to know we are using the country’s intellectual and technical capacity to deliver outcomes that matter to them – stronger communities, more good jobs, a cleaner environment, better public services, a richer culture, greater security for themselves and their children. Everybody here knows the rules of professional scientific conduct – think independently, put emotion aside, reject received authority, be faithful to the evidence, communicate openly.

These are good rules – rules I wholeheartedly endorse – but there’s one more I’d like to add – remember your humanity. Remember you’re part of a wider society – one that you have a special ability and therefore a special duty to serve. This doesn’t just apply in the physical sciences, but in the humanities and social sciences as well. When I say science I mean knowledge in all its forms.

Students Create “Disappearing” Nail Polish

‘Vanishing’ colour gives schoolgirls chance to beat ban on nail varnish

A nail varnish that “vanishes” has been developed by a group of school pupils – offering girls the chance to beat bans on makeup. The nail colour is a vivid red outdoors – but inside it transforms to a much paler shade which can hardly be seen.

The dramatic change is caused by a chemical reaction between the varnish and the ultraviolet light in natural sunlight. The polish was devised by pupils from Albion High School, Salford, who thought the “vanishing” colour may help them beat the school’s ban on nail polish.
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They came up with the idea while working on an enterprise project with Paul Haywood and Sam Ingleson from Salford University’s school of art and design.

Not exactly what I would create but it is great to see students using scientific thought to find solutions they desire.

Scientific American Frontiers Webcasts

All shows of the PBS TV show, Scientific American Frontiers are available online. The shows feature Alan Alda exploring a wide range of scientific ideas. Specific information for teachers if provided for each show. Shows include:

Going Deep – “In 1977, scientists aboard Alvin were exploring the Galapagos Rift in the Pacific Ocean when they made one of the most important discoveries in modern biology. Hydrothermal vents are underwater volcanoes erupting magma-heated, mineral-rich water out of cracks on the seafloor thousands of feet beneath the surface. Despite the enormous pressure and total darkness, the vents were found to support an astonishing array of animal life.”
The Dark Side of the Universe – Dark matter, dark energy and the universe.
Natural Born Robots – “The next generation of robots swim like fish, play soccer and even experience emotions.”
Science and Sports – “Science enables people to run quicker, climb higher, hit farther, and sail faster in this sports special.”

Radiation Tolerant Bacteria

metallireducens bacteria

This image is from the Eye of Science web site (which has many great images):

Bacteria: Uranium waste bacteria (metallireducens bacteria) [the green in the image] Electron microscopy… This bacteria is able to survive in radioactive environments and turn the uranium waste from a soluble form (that can contaminate water supplies) to a solid form.

Other species of Geobacter bacteria can eliminate petroleum contamination in polluted water and convert waste organic matter to electricity. Geobacter sp. are anaerobic bacteria (living without oxygen) that use metals to gain energy in the same way that humans use oxygen. Coloured scanning electron micrograph, Magnification: x3,600 and x4,800

Explaining the Missing Antimatter

Flipping particle could explain missing antimatter

It is one the biggest mysteries in physics – where did all the antimatter go? Now a team of physicists claims to have found the first ever hint of an answer in experimental data. The findings could signal a major crack in the standard model, the theoretical edifice that describes nature’s fundamental particles and forces.

In its early days, the cosmos was a cauldron of radiation and equal amounts of matter and antimatter. As it cooled, all the antimatter annihilated in collisions with matter – but for some reason the proportions ended up lopsided, leaving some of the matter intact.

Physicists think the explanation for this lies with the weak nuclear force, which differs from the other fundamental forces in that it does not act equally on matter and antimatter. This asymmetry, called CP violation, could have allowed the matter to survive to form the elements, stars and galaxies we see today.
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“It is tantalisingly interesting at the moment,” says Val Gibson, an expert on B meson physics at the University of Cambridge. “If it is true, it is earth-shattering.” Jacobo Konigsberg, who leads the CDF collaboration, says that Tevatron researchers are “cautiously excited” about the analysis. He points out that more data needs to be analysed to rule out a statistical fluke, which has happened several times before in particle physics.

Drug Price Crisis

I don’t think the suggestion below really solves the drug price crisis. But I do think it is an example of an educational and research institution actually proposing sensible role for themselves. As I have said too many universities now act like they are for-profit drug or research companies: Funding Medical Research. For some background on drug prices read my post on the Curious Cat Management blog from 2005.

Solving the drug price crisis

The mounting U.S. drug price crisis can be contained and eventually reversed by separating drug discovery from drug marketing and by establishing a non-profit company to oversee funding for new medicines, according to two MIT experts on the pharmaceutical industry.
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Following the utility model, Finkelstein and Temin propose establishing an independent, public, non-profit Drug Development Corporation (DDC), which would act as an intermediary between the two new industry segments — just as the electric grid acts as an intermediary between energy generators and distributors.

The DDC also would serve as a mechanism for prioritizing drugs for development, noted Finkelstein. “It is a two-level program in which scientists and other experts would recommend to decision-makers which kinds of drugs to fund the most. This would insulate development decisions from the political winds,” he said.

Book – Reasonable Rx: Solving the Drug Price Crisis by Stan Finkelstein and Peter Temin

Peru Meteorite Provides Puzzles

Peru meteorite may rewrite rules

Usually, only meteorites made of metal survive the passage through Earth’s atmosphere sufficiently intact to scoop out a crater. But the object which came down in the Puno region of Peru was a relatively fragile stony meteorite. During the fiery descent through Earth’s atmosphere, these are thought to fragment into smaller pieces which then scatter over a wide area.

Yet pieces of the estimated 1m-wide meteorite are thought to have stayed together during entry, hitting the ground as one.
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Peter Schultz told the conference that the meteorite was travelling at about 24,000km/h (15,000mph) at the moment of impact – much faster than would be expected. “This just isn’t what we expected,” said Professor Schultz, from Brown University in Providence, US. “It was to the point that many thought this was fake. It was completely inconsistent with our understanding of how stony meteorites act.”
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At the velocity it was travelling, fragments could not escape the “shock-wave” barrier which accompanies the meteorite’s passage through the atmosphere. Instead, the fragments may have reconstituted themselves into another shape, which made them more aerodynamic. Consequently, they encountered less friction during their plunge to Earth, holding together until they reached the ground. “Although [the meteorite] is quickly broken up, it is behaving like a solid mass,” Professor Schultz told the conference.

Excellent article. First it is just interesting. Also it shows how scientists have to learn from what they observe and try to understand what explains the results they see.