Category Archives: Research

Atom-thick Carbon Transistor

Atom-thick carbon transistor could succeed silicon by Tom Simonite:

Transistors more than four times smaller than the tiniest silicon ones – and potentially more efficient – can be made using sheets of carbon just one-tenth of a nanometre thick, research shows. Unlike other experimental nanoscopic transistors, the new components require neither complex manufacturing nor cryogenic cooling.

The transistors are made of graphene, a sheet of carbon atoms in a flat honeycomb arrangement. Graphene makes graphite when stacked in layers, and carbon nanotubes when rolled into a tube. Graphene also conducts electricity faster than most materials since electrons can travel through in straight lines between atoms without being scattered. This could ultimately mean faster, more efficient electronic components that also require less power.

How to Deal with False Research Findings

The Science of Getting It Wrong: How to Deal with False Research Findings by JR Minkel adds to our recent spate of posts on drawing faulty conclutions from data (such as: Correlation is Not Causation, Cancer Deaths – Declining Trend?, Seeing Patterns Where None Exists, Karl Popper Webcast).

In his widely read 2005 PLoS Medicine paper, Ioannidis, a clinical and molecular epidemiologist, attempted to explain why medical researchers must frequently repeal past claims. In the past few years alone, researchers have had to backtrack on the health benefits of low-fat, high-fiber diets and the value and safety of hormone replacement therapy as well as the arthritis drug Vioxx, which was pulled from the market after being found to cause heart attacks and strokes in high-risk patients.

Using simple statistics, without data about published research, Ioannidis argued that the results of large, randomized clinical trials—the gold standard of human research—were likely to be wrong 15 percent of the time and smaller, less rigorous studies are likely to fare even worse.

Among the most likely reasons for mistakes, he says: a lack of coordination by researchers and biases such as tending to only publish results that mesh with what they expected or hoped to find. Interestingly, Ioannidis predicted that more researchers in the field are not necessarily better—especially if they are overly competitive and furtive, like the fractured U.S. intelligence community, which failed to share information that might have prevented the September 11, 2001, terrorist strikes on the World Trade Center and the Pentagon.

But Ioannidis left out one twist: The odds that a finding is correct increase every time new research replicates the same result, according to a study published in the current PLoS Medicine.

Tracking Changes in Individual Molecules

Watching a Biological Jigsaw Puzzle Come Together

Scientists have recorded the action involved in assembling telomerase, an enzyme used by cells to protect their genes during the potentially dangerous process of DNA replication. Using a sophisticated technique for tracking structural changes in individual molecules in real time, they have revealed how three of the protein and RNA components of the enzyme come together, altering their shapes along the way to ensure that the next piece will fit.
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In these more complicated systems, it’s much harder to guess what is going on in the assembly process. But by directly watching things as they happen, this sort of powerful approach will give a lot of new insights.

Very cool stuff. It just keeps coming doesn’t it?

Correlation is Not Causation

Why so much medical research is rot:

People born under the astrological sign of Leo are 15% more likely to be admitted to hospital with gastric bleeding than those born under the other 11 signs. Sagittarians are 38% more likely than others to land up there because of a broken arm. Those are the conclusions that many medical researchers would be forced to make from a set of data presented to the American Association for the Advancement of Science by Peter Austin of the Institute for Clinical Evaluative Sciences in Toronto. At least, they would be forced to draw them if they applied the lax statistical methods of their own work to the records of hospital admissions in Ontario, Canada, used by Dr Austin.

Dr Austin, of course, does not draw those conclusions. His point was to shock medical researchers into using better statistics, because the ones they routinely employ today run the risk of identifying relationships when, in fact, there are none. He also wanted to explain why so many health claims that look important when they are first made are not substantiated in later studies.

As I said in, Seeing Patterns Where None Exists: “Page 8 of Statistics for Experimenters by George Box, William Hunter (my father) and Stu Hunter (no relation) shows a graph of the population (of people) versus the number of storks which shows a high correlation. “Although in this example few would be led to hypothesize that the increase in the number of storks caused the observed increase in population, investigators are sometimes guilty of this kind of mistake in other contexts.'”

Nanoparticles to Battle Cancer

photo of Todd Harris, Sangeeta Bhatia and Geoffrey von Maltzahn

Team develops nanoparticles to battle cancer:

One solution already under way involves using nanoparticles for cancer imaging. By slipping through tiny gaps that exist in fast-growing tumor blood vessels and then sticking together, the particles create masses with enough of a magnetic signal to be detectable by a magnetic resonance imaging (MRI) machine. “This might allow for noninvasive imaging of fast-growing cancer ‘hot spots’ in tumors,” said Bhatia. The team will continue this research by testing the imaging capabilities in animal models.

Another solution, described in the Jan. 16 issue of the Proceedings of the National Academy of Sciences, is a novel “homing” nanoparticle that mimics blood platelets. Platelets flow freely in the blood and act only when needed, by keying in on injured blood vessels and accumulating there to form clots. Similarly, these new nanoparticles key in on a unique feature of tumor blood vessels.

Ruoslahti had identified that the lining of tumor vessels contains a meshwork of clotted plasma proteins not found in other tissues. He also identified a peptide that binds to this meshwork. By attaching this peptide to nanoparticles, the team created a particle that targets tumors but not other tissues. When injected into the bloodstream of mice with tumors, the peptide sticks to the tumor’s clotted mesh.

Photo by Donna Coveney, from related press release: MIT nanoparticles may help detect, treat tumors

Micro RNA Editing

What separates us from the worms by Tom Avril (bozos broke the link, poor usability, so I removed it):

RNA editing is thought to be just one way that humans get more out of their 30,000 genes than, say, a fruit fly does with 13,600 or a roundworm does with 19,100. Those creatures have more primitive editing machinery, said the paper’s senior author, Kazuko Nishikura of Philadelphia’s Wistar Institute.

And they have much less of what is sometimes misleadingly called “junk” DNA – a region of the genome that does not produce proteins but nevertheless appears to play a key role in the diversity of life. The new paper is one of numerous recent finds in the booming field of RNA research. In the early days of genetic study, RNA was seen basically as a messenger for its cousin, DNA, carrying instructions to direct the manufacture of proteins.

But other kinds of RNA have since been discovered, including some that regulate or turn off certain genes, playing a role in embryonic development and – when things go awry – in diseases such as cancer. Last year’s Nobel Prize in medicine was awarded to scientists who pioneered a related field called RNA interference. And RNA is now thought to be even older than DNA, with some saying it served as the genetic blueprint for the earliest forms of life.

Communication Emergence in Robots

Evolving Robotspeak by Carl Zimmer:

At first the robots just flashed their lights at random. But over time things changed. In the trials with relatives undergoing colony selection, twelve out of the twenty lines began to turn on the blue light when they reached the food. The light attracted the other robots, bringing them quickly to the food. The other eight lines evolved the opposite strategy. They turned blue when they hit the poison, and the other robots responded to the light by heading away.

Two separate communication systems had evolved, each benefiting the entire colony. By communicating, the robots also raised their score by 14%. Here’s a movie showing six of these chit-chatting robots finding a meal.

Related: The original paper, Evolutionary Conditions for the Emergence of Communication in Robots (pdf) by Dario Floreano, Sara Mitri, Stephane Magnenat and Laurent Keller – more robot related posts

Biomolecules in Motion

Biomolecules in Motion by Kathleen M. Wong:

Proteins are the parts that make living engines run. They supply cells with energy, build muscle and bone, and catalyze countless other reactions that let the spark of life burn bright. To do their jobs, proteins must curl around substrate molecules, stretch to let their substrates go, travel around cells and assemble into work crews.
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Scientists have long believed that when an enzyme is empty, it gapes open like a hungry alligator, and that after it has caught its substrate, it remains closed until the reaction has been completed. Yang’s single-molecule microscopy studies have turned this notion upside-down. “Even when it has substrate, it doesn’t just bind the substrate tightly and stop moving. It’s still flapping,” he says. This constant motion makes perfect sense, considering how fast enzymes operate; some can process a million substrate molecules per minute. “Like a door, it has to be able to swing even without me going in and out.

Aussies Look to Finnish Innovation Model

Aussies look to Finnish Innovation Model:

Australian policy makers are looking to Finland for inspiration in their drive to bring the nation closer to the dream of thriving technological innovation. The country’s president and other Finnish representatives are in Sydney to share with Australian researchers the strides the nation has made in the past three decades. Home of companies such as Nokia, the world’s largest mobile phone manufacturer, Finland has captured the attention of governments looking to shift their economic base away from traditional industries towards a more innovative focus.

Finland’s research and development spend accounts for 3.5 per cent of its gross domestic product (GDP), a higher percentage than that of most European Union nations. It intends to lift this percentage to four per cent by 2010. Australia’s spending on research in comparison was 1.8 per cent of GDP in 2004/05, below the Organisation for Economic Cooperation and Development (OECD) average of 2.3 per cent.

No Sleep, No New Brain Cells

No sleep means no new brain cells

The researchers compared animals who were deprived of sleep for 72 hours with others who were not. They found those who missed out on rest had higher levels of the stress hormone corticosterone. It would be interesting to see if partial sleep deprivation – getting a little bit less sleep every night that you need – had the same effect

They also produced significantly fewer new brain cells in a particular region of the hippocampus. When the animals’ corticosterone levels were kept at a constant level, the reduction in cell proliferation was abolished. The results suggest that elevated stress hormone levels resulting from sleep deprivation could explain the reduction in cell production in the adult brain.

Sleep patterns were restored to normal within a week. However levels of nerve cell production (neurogenesis) were not restored for two weeks, and the brain appears to boost its efforts in order to counteract the shortage.