The incredible eel

In a quest to design better and more efficient products, scientists continue to find the best models in God’s creation. Seth Fraden, a Brandeis University physicist, is attempting to create a robotic eel that will zigzag through the human bloodstream to deliver drugs to cells or genes in a fashion similar to an eel slithering through water.

Two columns of nerve cells, or neurons, flank an eel’s spine. When a nerve cell fires, it sets off a chain reaction that travels down the column and results in a wave of muscle contractions that curve the spine. When nerve cells in the first column activate, they also send a molecule to the second column that inactivates those cells until the process travels the length of the first column. Then, neurons in the second column wake up and start a new chain reaction, creating the smooth, waving motion that propels the eel forward.

Fraden and his team discovered they could mimic the activity of an eel’s neural network by creating similar chemical reactions in a series of compartments lined up in two adjacent columns. Just like the eel’s nerve cells, these chemical reactions flip back and forth between activity and inactivity, the team reported in the journal Lab on a Chip.

Fraden plans to place his artificial neural network in a shape-changing gel that can glide through water. “We hope the material will behave in the same way an eel’s body does in response to the firings of its ‘neurons,’” he told Science Blog. “It will slither away.”

The physicist hopes to imitate other designs in creation to make clothing that mends itself through the same process our cells use to heal a wound and nanobots that swim like a fish through water pipes to deliver materials to repair pipe damage.

Wish upon a living Mars

A NASA announcement last week that the Curiosity rover found organic molecules in Martian rocks fueled scientific speculation about life on the red planet. Curiosity also found seasonal variations in the level of atmospheric methane. NASA said both discoveries suggested our celestial neighbor could have supported life or might currently harbor microbes. But Discovery Institute experts said such notions represented wishful thinking, not objective analysis.

In a study published in the journal Science, the researchers discovered concentrations of organic material 100 times greater than previous measurements indicated. The finding excited researchers because biologists often associate those molecules with life. But, NASA noted, geologic processes, impacts from asteroids, comets, and meteors, or even interplanetary dust could also create them. Nevertheless, the discovery revved up scientific imaginations.

“With these new findings, Mars is telling us to stay the course and keep searching for evidence of life,” said Thomas Zurbuchen, NASA associate administrator for the Science Mission Directorate.

A second study, also appearing in Science, aroused even more speculation that microbial life might exist on Mars. Researchers found seasonal variations of methane, a gas that animals and plants produce on Earth, in the Martian atmosphere. They do not yet know the source of this gas. Chemical processes in water and rock could produce the compound, but the researchers said they can’t rule out a biological source.

Discovery Institute experts said many scientists and news outlets exaggerated the findings. The molecules Curiosity found are not in a “form that is important for life,” they wrote. —J.B.

Evidence of crucifixion

A new study of the skeletal remains of a man unearthed in 2007 near Venice, Italy, provided rare evidence of the Roman practice of crucifixion, Live Science reported. The analysis shows an unhealed lesion and fracture of the heel bone that suggests someone nailed the man’s feet to a cross.

Though the practice of crucifixion in Rome was documented—most notably in the Bible—scientists until now have found only one other case of archeological evidence for it. Genetic and biological tests revealed the remains from Venice belonged to a short, slim man between the ages of 30 and 34. Due to his small build, the archeologists believe he was likely an underfed slave. The scientists found no indication of nails pounded into the man’s hands, but executioners also commonly tied victims’ arms to the cross.

The Romans used crucifixion for nearly a thousand years until Emperor Constantine banned it in the fourth century. Archeologists found the only other evidence of the punishment during a 1968 dig of Roman-era tombs in Jerusalem. The scientists discovered the remains of a man with a 7-inch long nail driven through his heel bone and attached to a small piece of olive wood.

Identification of crucifixion victims poses a difficulty for archeologists because the bones that bore the injury fracture easily and make recognition and preservation challenging. Also, scientists usually don’t find the metal crucifixion nails because Roman authorities recycled them. —J.B.

Social media telephone game

Anyone who ever played the telephone game as a child, in which a phrase is whispered from one person to the next, knows how quickly a message can become distorted. Researchers at the University of Warwick recently discovered a similar process happens when adults pass news stories from one person to another, a disconcerting fact considering all the news that people retweet and comment on via social media.

The researchers divided 154 people into 14 chains of eight people each. The first person in each chain read a factual news article about a potential threat and then wrote a message about it to the next person in the chain, who then wrote a new message to the next in line and so on. In each chain the stories became increasingly negative and panicky. The researchers also gave the sixth person the original, neutral news story along with the story written by the previous person. Even when the sixth in line read the neutral, factual report, they still passed on negatively inaccurate information.

The study, published in Risk Analysis, shows that society amplifies risk, lead researcher Thomas Hill, said, adding, “It also shows that the more people share information, the further that information gets from the facts and the more resilient it becomes to correction.” —J.B.

Unnecessary chemo

Seventy percent of women with the most common type of breast cancer do not need chemotherapy, according to a recent study published in The New England Journal of Medicine. The researchers studied an international group of 10,273 women diagnosed with HRpositive, HER2-negative, axillary lymph node–negative breast cancer.

Based on former studies, oncologists generally recommend only hormone therapy for women at a low risk for recurrence of breast cancer and hormone therapy plus chemotherapy for those at high risk. Doctors often find themselves uncertain what to recommend for women at moderate risk.

In the study, researchers randomly assigned women at an intermediate range for risk of recurrence to one of two groups—one that received both hormone and chemotherapy and one that received hormone therapy alone. The results showed that chemotherapy offered no added benefit for most women in the moderate risk range. —J.B.