Category Archives: Science

Nanoparticles With Scorpion Venom Slow Cancer Spread

In a, chlorotoxin molecules, colored blue and green, attach themselves to a central nanoparticle. In b, each nanoprobe offers many chlorotoxin molecules that can simultaneously latch on to many MMP-2s, depicted here in yellow, which are thought to help tumor cells travel through the body. In c, over time nanoprobes draw more and more of the MMP-2 surface proteins into the cell, slowing the tumor’s spread. Image from the University of Washington.

University of Washington researchers found they could cut the spread of cancerous cells by 98 percent, compared to 45 percent for the scorpion venom alone, by combining nanoparticles with a scorpion venom compound already being investigated for treating brain cancer.

For more than a decade scientists have looked at using chlorotoxin, a small peptide isolated from scorpion venom, to target and treat cancer cells. Chlorotoxin binds to a surface protein overexpressed by many types of tumors, including brain cancer. Previous research by Miqin Zhang‘s group combined chlorotoxin with nanometer-scale particles of iron oxide, which fluoresce at that size, for both magnetic resonance and optical imaging.

Chlorotoxin also disrupts the spread of invasive tumors — specifically, it slows cell invasion, the ability of the cancerous cell to penetrate the protective matrix surrounding the cell and travel to a different area of the body to start a new cancer. The MMP-2 on the cell’s surface, which is the binding site for chlorotoxin, is hyperactive in highly invasive tumors such as brain cancer. Researchers believe MMP-2 helps the cancerous cell break through the protective matrix to invade new regions of the body. But when chlorotoxin binds to MMP-2, both get drawn into the cancerous cell.

Research showed that the cells containing nanoparticles plus chlorotoxin were unable to elongate, whereas cells containing only nanoparticles or only chlorotoxin could stretch out. This suggests that the nanoparticle-plus-chlorotoxin disabled the machinery on the cell’s surface that allows cells to change shape, yet another step required for a tumor cell to slip through the body.

So far most cancer research has combined nanoparticles either with chemotherapy that kills cancer cells, or therapy seeking to disrupt the genetic activity of a cancerous cell. This is the first time that nanoparticles have been combined with a therapy that physically stops cancer’s spread.

Full press release

Amazonian Ant Species is All Female, Reproduces By Cloning

Ants inhabit ‘world without sex’

The ants reproduce via cloning – the queen ants copy themselves to produce genetically identical daughters. This species – the first ever to be shown to reproduce entirely without sex – cultivates a garden of fungus, which also reproduces asexually.
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Dr Himler’s interest in Mycocepurus smithii was originally sparked not by their unusually biased sex ratio, but by their ability to cultivate crops. “Ants discovered farming long before we did – they have been cultivating fungus gardens for an estimated 80 million years.

“They collect plant material, insect faeces and even dead insects from the forest floor and feed it to their crops,” she said.

Home Experiment: Deriving the Gravitational Constant

Deriving the Gravitational Constant by Joe Marshall

In the summer of 1985 I was at home convalescing and being bored. It occurred to me one day that if Cavendish could determine the gravitational constant back in 1798, I ought to be able to do something similar
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Cavendish cast a pair of 1.61 pound lead weights. I found a couple of 2-pound lead cylinders my dad had lying around. I used duct tape to attach them to a 3-foot wooden dowel. Cavendish used a wire to suspend the balance, I used nylon monofilament. To determine the torsion of the fiber, you wait until the balance stops moving (a day or two) and then you slightly perturb it. The balance will slowly oscillate back and forth. The restoring force is calculated from the period of oscillation. Cavendish had a 7-minute period. My balance had a 40 minute period (nylon is nowhere near as stiff as wire).

Cavendish used a pair of 350 pound lead balls to attract the ends of the balance from about 9 inches away. I put a couple of 8 pound jugs of water about an inch away. The next trick was to measure the rotation of the balance. Cavendish had a small telescope to read the Vernier scale on the balance. I used some modern technology. I borrowed a laser from Tom Knight (Thanks again!), and bounced it off a mirror that I mounted on the middle of the balance. This made a small red dot on the wall about 20 feet away. (I was hoping this would be enough to measure the displacement, but I was considering an interferometer if necessary.)

To my surprise, it all worked. After carefully putting the jugs of water in place, the dot on the wall started to visibly move. Within a few minutes, it had moved an inch or two. I carefully removed the jugs of water and sure enough, the dot on the wall drifted back to its starting position.

Very cool example of a home physics experiment.

Bacteria Communicate Using a Chemical Language

Each person has about 1 trillion human cells and about 10 trillion bacterial cells. In the webcast Bonnie Bassler, Department of Molecular Biology at Princeton University, discusses the chemical language that lets bacteria coordinate defense and mount attacks (quorum sensing). The find has stunning implications for medicine, industry — and our understanding of ourselves.

Bacteria do all sorts of amazing things for us: educating your immune system to keep bad microbes out, they digest our food, they make our vitamins…

Fellowship Winners Announced

Several science and engineering fellowships and scholarships have announced winners recently:

NSF Graduate Research Fellowships
Goldwater Scholarships
Marshall Scholarships
Department of Defense (NDSEG) Fellowships – no online list of winners yet

From the NSF GRFP site:

Due to the complexity of the current budget situation, the 2009 GRFP awards will be announced in installments based on fields of study and other factors. The first installment is now available on FastLane. Awardees, as well as Applicants not recommended for funding, have been notified by email. Recipients of Honorable Mention and any additional Fellowship award offers will be forthcoming. Applicant ratings sheets will be available after all award announcements have been made. We thank you for your patience.

Find out more about these and other science and engineering fellowships and scholarships. Also see: How to Win a Graduate Fellowship – NSF Graduate Research Fellows 2008

Why Toddlers Don’t Do What They’re Told

Toddlers listen, they just store the information for later use, a new study finds.

“I went into this study expecting a completely different set of findings,” said psychology professor Yuko Munakata at the University of Colorado at Boulder. “There is a lot of work in the field of cognitive development that focuses on how kids are basically little versions of adults trying to do the same things adults do, but they’re just not as good at it yet. What we show here is they are doing something completely different.”
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“If you just repeat something again and again that requires your young child to prepare for something in advance, that is not likely to be effective,” Munakata said. “What would be more effective would be to somehow try to trigger this reactive function. So don’t do something that requires them to plan ahead in their mind, but rather try to highlight the conflict that they are going to face. Perhaps you could say something like ‘I know you don’t want to take your coat now, but when you’re standing in the yard shivering later, remember that you can get your coat from your bedroom.”

Using Virus to Build Batteries

MIT researchers have shown they can genetically engineer viruses to build both the positively and negatively charged ends of a lithium-ion battery. We have posted about similar things previously, for example: Virus-Assembled Batteries – Using Viruses to Construct Electrodes and Biological Molecular Motors. New virus-built battery could power cars, electronic devices

Gerbrand Ceder of materials science and Associate Professor Michael Strano of chemical engineering, genetically engineered viruses that first coat themselves with iron phosphate, then grab hold of carbon nanotubes to create a network of highly conductive material.

Because the viruses recognize and bind specifically to certain materials (carbon nanotubes in this case), each iron phosphate nanowire can be electrically “wired” to conducting carbon nanotube networks. Electrons can travel along the carbon nanotube networks, percolating throughout the electrodes to the iron phosphate and transferring energy in a very short time. The viruses are a common bacteriophage, which infect bacteria but are harmless to humans.

The team found that incorporating carbon nanotubes increases the cathode’s conductivity without adding too much weight to the battery. In lab tests, batteries with the new cathode material could be charged and discharged at least 100 times without losing any capacitance. That is fewer charge cycles than currently available lithium-ion batteries, but “we expect them to be able to go much longer,” Belcher said.

This is another great example of university research attempting to find potentially valuable solutions to societies needs. See other posts on using virus for productive purposes.

Robot Independently Applies the Scientific Method

Robot achieves scientific first by Clive Cookson

A laboratory robot called Adam has been hailed as the first machine in history to have discovered new scientific knowledge independently of its human creators. Adam formed a hypothesis on the genetics of bakers’ yeast and carried out experiments to test its predictions, without intervention from its makers at Aberystwyth University.

The result was a series of “simple but useful” discoveries, confirmed by human scientists, about the gene coding for yeast enzymes. The research is published in the journal Science.
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Adam is the result of a five-year collaboration between computer scientists and biologists at Aberystwyth and Cambridge universities.

The researchers endowed Adam with a huge database of yeast biology, automated hardware to carry out experiments, supplies of yeast cells and lab chemicals, and powerful artificial intelligence software. Although they did not intervene directly in Adam’s experiments, they did stand by to fix technical glitches, add chemicals and remove waste.
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“Adam is a prototype,” says Prof King. “Eve is better designed and more elegant.” In the new experiments, Adam and Eve will work together to devise and carry out tests on thousands of chemical compounds to discover antimalarial drugs.

Very cool.

E.O. Wilson: Lord of the Ants

This is a great webcast on E.O Wilson‘s career studying ants and animal behavior from NOVA.

Not only is the scientific knowledge very interesting it again shows that challenging conventional wisdom, while part of the scientific method, does not mean it is an easy process for those pioneers. From his web site:

In 1971 Wilson published his second major synthesis, The Insect Societies, which formulated the existing knowledge of the behavior of ants, social bees, social wasps, and termites, on a foundation of population biology. In it he introduced the concept of a new discipline of sociobiology, the systematic study of the biological basis of social behavior in all kinds of organisms. In 1975 he published Sociobiology: The New Synthesis, which extended the subject to vertebrates and united it more closely to evolutionary biology. The foundational discoveries of sociobiology are generally recognized to be the analysis of animal communication and division of labor, in which Wilson played a principal role, and the genetic theory of the origin of social behavior, which he helped to promote and apply in his 1971 and 1975 syntheses. Sociobiology: The New Synthesis was later ranked in a poll of the officers and fellows of the international Animal Behaviour Society as the most important book on animal behavior of all time, and is regarded today as the founding text of sociobiology and its offshoot, evolutionary psychology.

Related: Journey to the Ants: A Story of Scientific Exploration
by Bert HÃ¶lldobler and Edward O. Wilson – Huge Ant Nest – Symbiotic relationship between ants and bacteria – Royal Ant Genes – posts on ants – Encyclopedia of Life

Robot with Biological Brain

The Living Robot by Joe Kloc

Life for Warwick’s robot began when his team at the University of Reading spread rat neurons onto an array of electrodes. After about 20 minutes, the neurons began to form connections with one another. “It’s an innate response of the neurons,” says Warwick, “they try to link up and start communicating.”

For the next week the team fed the developing brain a liquid containing nutrients and minerals. And once the neurons established a network sufficiently capable of responding to electrical inputs from the electrode array, they connected the newly formed brain to a simple robot body consisting of two wheels and a sonar sensor.
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At first, the young robot spent a lot of time crashing into things. But after a few weeks of practice, its performance began to improve as the connections between the active neurons in its brain strengthened. “This is a specific type of learning, called Hebbian learning,” says Warwick, “where, by doing something habitually, you get better at doing it.”
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“It’s fun just looking at it as a robot life form, but I think it may also contribute to a better understanding of how our brain works,” he says. Studying the ways in which his robot learns and stores memories in its brain may provide new insights into neurological disorders like Alzheimer’s disease.