Bomb-Sniffing Bionic Plants Could Look for Pollution By Edd Gent, Live Science Contributor

Plants embedded with carbon nanotubes could detect explosives and wirelessly relay the information to an electronic device.

Credit: Juan Pablo Giraldo/UCR

Bionic plants that can detect explosives in real time could be the future of environmental monitoring and urban farming, researchers said in a new study.

The spinach plants have carbon-nanotube-based nanoparticles in their leaves that give off infrared lightand are sensitive to the presence of nitroaromatics, key components of several explosives, the scientists said.

If these chemicals are present in groundwater, they are absorbed by the roots and transported to the leaves, where they cause the infrared emissions of the so-called "nanosensor" to decrease. [In Photos: World's Most Polluted Places]

A detector that is similar in complexity to a smartphone can then register this change in emissions, the researchers said. In tests with the nitroaromatic picric acid, this dip was detected within 10 minutes of the roots taking up the chemical, according to the study, published today (Oct. 31) in the journal Nature Materials.

The researchers said their "nanobionic" approach is much faster than previous genetic engineering methods that rely on monitoring changes like wilting or de-greening that can take hours or days and aren't easy to detect electronically. The scientists also used a wild breed of spinach rather than special lab-grown varieties. The researchers said they are confident they can replicate the method with a broad range of plant species that are well-adapted to their environments.

"Genetic engineering is very powerful, but in practice there are only a handful of plants where this can be done. We can take a plant in your backyard and easily engineer it" using nanobionics instead of genetics, said study leader Michael Strano, a professor of chemical engineering at the Massachusetts Institute of Technology (MIT).

Diagram showing detection set-up with the nanobionic sensing plant.

Credit: Juan Pablo Giraldo/UCR

Power of plants

Strano said plants make excellent chemical sensors due to the organisms' extensive network of roots and their ability to draw up groundwater using minimal amounts of solar energy. This is thanks to a process known as transpiration, in which moisture evaporates from the leaves, causing water to be drawn up from the roots.

Because the water evaporates, chemicals drawn up along with the fluid that don't easily vaporize get concentrated in the leaves. This means plants can detect very low concentrations of chemicals, the scientists said.

The nanosensor used in the study is sensitive to a broad range ofexplosives and can even detect chemicals that are produced as explosives degrade, the researchers said.

To pick up the infrared signal, the group used a small infrared camera connected to a $35 Raspberry Pi minicomputer, but Strano told Live Science that a smartphone could be easily adapted to the job if its infrared filter was removed.

Testing of the system was carried out at a distance of about 3.3 feet (1 meter), but Strano said the sensor should be capable of a much wider range, which would allow one sensor to monitor multiple plants. This is because a second fluorescent nanoparticle added along with the nanosensor is not sensitive to nitroaromatics, and so provides a constant reference infrared signal to compare against what's being picked up by the nanosensor.

"What we are interested in doing is showing we can make a really robust human-plant interface," Strano said. "The reference signal means you can intercept this IR signal from any angle, at any distance accurately and quickly." [Top 10 Craziest Environmental Ideas]

Important step

Bogdan Dragnea, a professor of chemistry at Indiana University who specializes in nanotechnology but wasn't involved with the new study, said the work marks an exciting step toward better monitoring of soil contamination.

"A potential caveat is related to possible clearance, and/or biofouling of the transducer by the plant, and the possibility of false positives, but presumably such issues will be addressed further along the road," Dragnea told Live Science.

Strano said his group hopes to increase the number of sensors that can be applied to plants so the instruments can detect a variety ofchemicals in both the air and groundwater. He said he also wants to use nanotechnology to give plants the ability to react to these signals in ways not found in nature.

"A plant can monitor its own environment for pest infestations, damage, drought," Strano said. "They're very sensitive readers of their own physiology, and we're interested in extending this approach and tapping into plants' own complex signaling pathways."

Strano and the paper's lead author, MIT graduate student Min Hao Wong, have started a company called Plantea to look into how to commercialize the technology. Strano said he thinks urban farming is a promising market because these farms need to be ultra-efficient to make the best use of expensive land. Plus, the plants would be in an enclosed space, making them easier to monitor, he added.

Raffaele Di Giacomo, a postdoctoral scholar at ETH Zurich in Switzerland, who also works on nanobionics but was not involved with this study, said the approach may encounter some difficulties with calibration and stability, but the system's simplicity and low cost should compensate for this.

"I don't doubt that in the near future we will have commercial sensing plants in our home or offices that will send us directly on our smartphone data about temperature, humidity, oxygen and pollutants," he told Live Science.

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Original Bedrock of Jesus' Tomb Revealed in New Images By Stephanie Pappas, Live Science Contributor |

An unobscured view of the limestone bedrock of the tomb said to belong to Jesus Christ.

Credit: ODED BALILTY / NATIONAL GEOGRAPHIC

New images from a conservation project in Jerusalem reveal the original limestone bed where the body of Jesus Christ is said to have been laid out after his crucifixion.

The rock-hewn burial platform was exposed for just moments as conservators from the National Technical University of Athens worked to shore up the shrine surrounding the site. Their efforts revealed a marble casing with a cross carved into it that may date back to the Crusader era, between the 11th and 16th centuries. The team also found remnants of the original rock wall of the tomb.

"I'm absolutely amazed. My knees are shaking a little bit because I wasn't expecting this," Fredrik Hiebert, an archaeologist with the National Geographic Society, a partner in the excavations, told National Geographic magazine, which originally reported the findings. [Jesus' Tomb: See Photos of the Church of the Holy Sepulchre] 

The making of a holy site

The conservation effort is the culmination of nearly 60 years of negotiations, but the story really begins nearly 1,700 years ago. The supposed site of Jesus' burial was first identified as a holy place in A.D. 326, when Helena, the mother of the Christian Roman emperor Constantine, traveled to Jerusalem and asked locals where Christ had been crucified and buried. She was pointed to a limestone cave in an area pocked with first- and second-century burials. According to Orthodox tradition, Helena ordered excavations and found not only Jesus' tomb, but three crosses and some iron nails. To determine which cross Jesus had died on, church officials held each over corpses on their way to be buried. One of the crosses brought a corpse back to life, revealing it to be the true cross, according to Orthodox readings.

A restorer brushes loose dirt and dust from the original limestone surface of what is said to be the tomb of Jesus Christ.

Credit: ODED BALILTY / NATIONAL GEOGRAPHIC

Atop the site was a pagan temple, which Helena and Constantine ordered to be torn down. The top of the cave was removed, and a new shrine was built over the tomb so that pilgrims could look down and view the stone. Meanwhile, construction began on the sprawling Church of the Holy Sepulchre surrounding the shrine. The church took about 10 years to build, according to the histories of the Eastern Orthodox Church. Another wing surrounds the spot where Jesus is said to have been crucified. [Proof of Jesus Christ? 7 Pieces of Evidence Debated]

The shrine itself is known as the Holy Edicule. By 1555, marble cladding had been put over the original limestone to protect it from souvenir seekers and graffiti carvings. This cladding had not been removed until today's ongoing conservation project. The shrine itself has been damaged and rebuilt many times over the centuries, most recently in the early 1800s, after a fire destroyed it.

Saving history

The Greek Orthodox Church, the Armenian Orthodox Church and the Roman Catholic Church jointly control the Church of the Holy Sepulchre, with some presence by the Syriac Church, the Egyptian Copts and the Ethiopian Orthodox Church. The main stakeholders agreed in 1958 that the Edicule that surrounds the original rock tomb needed to be preserved; already, it was being held up by ugly iron girders.

It took nearly 60 years for all of these groups to agree on a conservation proposal. The National Technical University of Athens opened the marble cladding that had been in place for at least 500 years last week, revealing a layer of loose fill material. Painstakingly brushing it away, they uncovered one last layer of marble and the original limestone bedrock on Friday (Oct. 28), National Geographic reported.

"We can't say 100 percent, but it appears to be visible proof that the location of the tomb has not shifted through time, something that scientists and historians have wondered for decades," Hiebert told the magazine. [In Photos: A Journey Through Early Christian Rome]

An investigation by University of Oxford archaeologist Martin Biddle more than 20 years ago suggested that the Edicule might contain a first-century tomb, said Ken Dark, an archaeologist at the University of Reading who was not involved in the excavations. The new project, which provided a high-tech look at the structure, was unique in that it looked at the original tomb itself, Dark told Live Science.

"The GPR [ground-penetrating radar] survey may indicate that much more of the rock-cut tomb survives inside the surrounding structure than was expected," Dark said. "If so, this is the really important discovery from the work reported."

Connection to Christianity

The rough limestone bed that restorers uncovered was protected by a broken slab of marble inscribed with a small cross.

Conservators have already replaced the marble, hiding the limestone away, perhaps permanently. The team injected mortar around the limestone slabs intended to be a permanent solution to preserving the Edicule. The restoration work will continue into spring, but when it is complete, workers will be able to remove the iron girders around the Edicule, offering an unobstructed view of the structure.

The team also left a piece of the limestone wall of the original tomb exposed so that pilgrims will be able to view it on visits to the shrine, National Geographic reported. The researchers have been documenting each portion and layer of the tomb for future study. Graffiti on the stone could reveal more of the history of the tomb, Biddle told National Geographic.

"The surfaces of the rock must be looked at with the greatest care," he said.

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Mixing Energy Drinks with Alcohol Causes Brain Changes in Mice By Agata Blaszczak-Boxe, Contributing Writer

Credit: Ash Pollard/Shutterstock.om

Energy drinks are oftencombined with alcohol in mixed drinks, and a new study in mice hints at how that combination may change the brain. 

In the study, mice that were givenenergy drinks along with alcohol had changes in their brains similar to those seen in mice given cocaine.

It isn't clear whether the findings apply to humans. But the study suggests it's possible that teens who drink these beveragesin combination might experience similar brain changes, the scientists said. The beverage combination may lead to changes in the brain's ability to respond to rewarding substances, and those changes could last into adulthood, the researchers said. [5 Health Problems Linked to Energy Drinks]

"We're clearly seeing effects of the combined drinks that we would not see if drinking one or the other," study co-author Richard van Rijn, an assistant professor of medicinal chemistry at Purdue University, said in a statement. "It seems the two substances together push [adolescent mice] over a limit that causes changes in their behavior and changes the neurochemistry in their brains."

Energy drinks, which are frequentlymarketed to teens, can contain up to 10 times the amount of caffeine as an equal amount of soda, according to the researchers. But scientists know little about how these drinks might affect teens' health, they said.

In the study, the researchers wanted to test the health effects of consuming both alcohol and energy drinks. For ethical reasons, such studies cannot be conducted in human teenagers, so the researchers decided to look at these effects in adolescent mice. [10 Facts Every Parent Should Know About Their Teen's Brain]

In one experiment, the researchers gave one group of mice access to both energy drinks and water, and gave another group access only to water. After a month, they gave all of the mice a choice between drinking water and drinking alcohol. They found no significant differences in how much alcohol these two groups drank.

But then, the researchers conducted a similar experiment, with three groups of mice: Some were given access to a mixture with high levels of caffeine and alcohol, some were given access to only caffeine and some were given access to only alcohol. All of the mice had access to water and food throughout the study.

At the end of the month, the researchers looked at the mice's brains. They found that the mice that drank the mixture of caffeine and alcohol showed increased levels of a certain protein, which is a marker of changes in brain chemistry, compared with the mice that drank either only alcohol or only caffeine.

In the mice that drank the mixture, the levels of this protein marker were similar to those that occur in mice that are allowed access to drugs such as cocaine or morphine.

Then, the researchers exposed the mice to cocaine. They found that the mice that had been given the caffeine-and-alcohol mixture were less sensitive to the pleasant effects of cocaine, compared with the mice that were not given the mixture. In other words, those mice would have had to use more cocaine to feel the pleasant "high" than the other mice would have.

"Mice that were exposed to highly caffeinated alcoholic drinks later found cocaine wasn't as pleasurable," van Rijn said. "They may then use more cocaine to get the same effect."

It seemed that drinking the mixture left the mice "somewhat numb to the rewarding effects of cocaine as adults," van Rijn said.

This finding could have implications for addiction, the researchers said.

More research is needed to confirm the findings. Previous studies of other drugs in mice and in humans have shown that changes in mouse brains triggered by the abuse of these drugs are similar to the changes that occur in human brains, the researchers said. Nonetheless, it remains unclear whether the new findings would occur the same way in humans.

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Italy Quakes: What Makes an Earthquake an Aftershock? By Mindy Weisberger, Senior Writer

Damaged buildings in Arquata del Tronto, Italy, following a massive earthquake on Oct. 30, 2016.

Credit: Giuseppe Bellini/Getty Images

A magnitude-6.6 earthquake that rocked central Italy on Sunday (Oct. 30) was not only the strongest earthquake to strike the region in 36 years, but it was also the latest in a series of powerful tremors. Those originated Aug. 24, with a magnitude-6.2 temblor, and then ramped up again Oct. 26 with two formidable quakes.

And the shaking didn't end on Oct. 30. Following the earthquake, Italy's geophysics and volcanology institution Istituto Nazionale di Geofisica e Vulcanologia (INGV)reported 560 post-quake tremors, which are typically referred to as aftershocks.

While most aftershocks are minor, some can be as strong as the earthquake that preceded them. So, what distinguishes aftershocks from earthquakes, and how do geologists interpret these events to understandseismic activity in Italy and in other earthquake-prone regions worldwide? [The 10 Biggest Earthquakes in History]

Earthquakes typically happen in groups, and scientists use the terms earthquake and aftershock to describe when in the sequence a tremor occurred, said Michael L. Blanpied, the associate coordinator of the U.S. Geological Survey (USGS) Earthquake Hazards Program.

Seismologists refer to the biggest quake in a sequence as the "main shock," Blanpied told Live Science. Quakes that precede it are "foreshocks," and quakes that follow the main event are "aftershocks."

Sometimes, however, an aftershock emerges that is more powerful than the main shock that happened earlier.

"Then we shuffle around the names," Blanpied said. "We call the new biggest one the main shock. We call the earlier ones foreshocks, and the ones that come after it are aftershocks.

"It's our way of sorting things out," he explained. "But they're all earthquakes."

Forecasting the swarm

In central Italy, earthquake sequences typically produce lots of tremors. "They tend to come in what we call swarms," Blanpied said. But it's hard for scientists to know if a cluster of aftershocks will produce a powerful event or simply peter out, he said.

"The rate of the earthquakes can rise or fall, and there may be more than one big one in the midst. Trying to forecast the future activity in such a swarm is extremely difficult," he said.

Geologically speaking, the faults that fuel Italy's quakes are young, only about 1 million years old. They run down the spine of the Apennine Mountains and are relatively small, so they can't generate massive quakes like those created by longer and older faults, such as the San Andreas in California.

"In mature faults, once an earthquake gets going, it can race along for long distances —that's where you can get the magnitude-7 to -8 quakes," Blanpied said. "In a more youthful, broken-up mélange of faults like we have in central Italy, one particular piece of fault may only be big enough to host a 5- to 6-magnitude earthquake."

Layers of stress

But in areas veined with shorter faults, like in central Italy, a quake can send a cascade of stresses into faults nearby, pushing them closer to the brink, when they would slip and trigger yet another earthquake, Blanpied said.

According to Blanpied, the recent tremors can be linked back to quakes that visited the region in August. As those faults triggered quakes, they also moved stress onto faults to the south, which are creating the big earthquakes now, Blanpied said. And these recent quakes could in turn shunt stress into more faults, potentially triggering even more earthquakes.

"What we don't know is if additional faults big enough to make magnitude-6 quakes will now be brought closer to failure," Blanpied said.

He explained that Italian seismologists are currently in the field, mapping fault ruptures and closely examining the locations of new earthquakes. The researchers are working to determine which faults have moved and by how much, and how that could increase the stress load in other faults, making them prone to quakes as well.

"We hope that the sequence will die off now," he added. "But we have to see. We have no way to predict that for sure."

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