• Laser detects roadside bombs

    Kurt Stepnitz

    Michigan State University professor Marcos Dantus works with an associate in his laboratory in the Chemistry building.

    By John Roach, Contributing Writer, NBC News

    Lab scientists are pitching a new high-tech laser that is able to detect roadside bombs before they explode, potentially thwarting the deadliest weapon in Iraq and Afghanistan.

    Roadside bombs, known as improvised explosive devices or IEDs, account for 60 percent of coalition soldiers' deaths, according to NATO figures. Finding a way to improve on — or at least replace — bomb sniffing dogs is therefore a priority abroad and at home. 

    Using lasers to do the dirty work is an ongoing effort. This latest approach combines short and long pulses of light to excite and "listen" to the fingerprint of individual molecules, allowing soldiers to pick out explosives in a crowded urban environment.

    "We are using an ultrashort pulse that whenever it gets to the molecule at the target, it gives it a kick in a very, very short timescale," Marcos Dantus, who is leading the research at Michigan State University, explained to me on Monday. "The molecule starts vibrating." 

    Dantus likened this vibration to an individual ring tone people might put on their cellphones. The longer laser pulse "listens" to this ring tone, allowing soldiers to know if the target is a bomb. 

    The technique is so sensitive, he added, that it can distinguish between molecules that have the same chemical formula but a slight different arrangement of atoms. What's more, a laser no more powerful than the ones used during PowerPoint presentations is required for the technique to work. 

    This differs from an approach Princeton University engineers unveiled this March that bounces ultraviolet pulses off chemicals in the air, carrying the fingerprint of the molecules.

    "Our approach uses 100 times less energy per pulse, can detect much lower concentrations," Dantus noted in a follow-up email exchange. "Our method was designed for solid targets with approximately one -billionth of a gram of an explosive mixed with other compounds." 

    The laser bomb sniffing technology is currently undergoing development in the laboratory. It has been shown to work at distances up to about 40 feet, though should be possible at distances of 330 feet. "Beyond that, we need engineers who know how to handle longer distances," Dantus said.

    His team is currently seeking funding to bring the technology from the lab out into the field. If secured, Dantus said, it would take about a year to deploy a system that can function, for example, in a mobile unit. 

    More stories on military technology:

    A paper on the laser technology appears in the current issue of Applied Physics Letters and is available here. The research is funded, in part, by the U.S. Department of Homeland Security.

    John Roach is a contributing writer for msnbc.com.

    From tablets in high school to electronic whiteboards and rotating walls in college, we look at how technology is remaking the classroom.

     

    4 comments

    Get this thing funded and into the field, pronto!!

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  • Scientists turn cells into lasers

    Malte Gather / Nature Photonics

    A human kidney cell produces green laser light inside a resonator.

    By Nidhi Subbaraman

    Physicists and molecular biologists have created the world's first biological laser, with live, glowing kidney cells at its core.

    At the heart of a laser is a substance that can absorb, amplify and emit light in a single focused beam. This role has been played by a string of characters over the years: semiconductors, crystals, dyes and even gases. Until now, living cells weren't part of that cast lineup. There's a good reason for that: Most living things, with the exception of some bioluminescent jellyfish, don't naturally trap or emit light.

    But recently, other organisms have acquired the ability to shine. The researchers behind these glow-in-the-dark animals owe their thanks to Osamu Shimomura, who extracted the green fluorescence protein and the genes that make GFP from the glowing guts of those jellyfish. (Coincidentally, he started work on the bioluminescent crystal jellyfish in 1960 — the same year that the laser was invented.) 

    Since then, molecular biologists have gone gaga over the GFP gene and other fluorescence genes. They use them as visual signals indicating that the other genes they study have been successfully transferred into different organisms (such as cats and dogs). The ever-expanding popularity of fluorescence genes among molecular biologists earned its discoverers a shiny Nobel in 2008. Now the GFP gene itself is stealing the spotlight.

    "Almost any organism, from bacteria to higher mammalians, can be programmed to synthesize such luminescent proteins, so we wondered if GFP could be used to amplify light and build biological lasers," Malte Gather and Seok Hyun Yun, the two physicists behind the "biolaser," wrote in a Q&A interview with Nature Photonics. The journal published their paper online on Sunday.  

    Guiliano Scarcelli

    Malte Gather and Seok Hyun Yun are the inventors of the biological laser.

    The researchers reprogrammed a line of human embryonic kidney cells with an enhanced version of the GFP gene. Then they sandwiched those cells between highly reflective mirrors and pulsed a blue light through the chamber.

    In their optically active compartment, the cells absorbed and re-emitted a laser-worthy green light for several minutes. The mirrors amplified the light to create a coherent beam, just as they do in non-biological lasers.

    The cells survived for a few hours after the lasing ordeal, and seemed to be actively producing and reabsorbing the green fluorescence protein. This could mean that, unlike regular lasers which wear out with use, "the laser can self-heal," they told Nature Photonics.

    The two physicists are now working on ways to tweak the setup so that it can be used as a living imaging tool. Such lasers may shed new light, so to speak, on biological processes within the cell, Gather told me: "The pattern of the laser light seems to carry information about the insides of the cell."

    Biolasers could also have medical applications. Some treatments, such as photodynamic therapy for cancer patients, use external lasers to stimulate drugs to be released close to a tumor. "You have a drug that attacks a tumor when you apply light," Gather said. "Using a laser light force from the inside would make this more efficient."

    Ultimately, the researchers want to free the lasing cell from its optical chamber, and somehow include tiny reflective mirrors within the cell itself. "For medical applications, that would be crucial," Gather said.  

    More on lasers:

    Nidhi Subbaraman is the science and tech news intern at msnbc.com. Find Nidhi on Twitter, and connect with the Cosmic Log on Facebook. 

  • X-ray laser lights up small wonders

    Thomas White (DESY)

    A three-dimensional rendering of X-ray data obtained from over 15,000 single nanocrystal diffraction snapshots recorded at the Linac Coherent Light Source, the world's first hard X-ray free-electron laser, located at SLAC National Accelerator Laboratory. The 3-D structure of proteins -- in this case Photosystem I -- can be determined from these diffraction patterns. Each nanocrystal was destroyed by the intense X-ray pulse, but not before information about its structure was revealed.

    By John Roach, Contributing Writer, NBC News

    Scientists are using intense, ultra-short X-ray pulses from a free-electron laser to collect data on the 3-D structure of proteins and single-shot images of an intact virus.

    The feat demonstrates a way to use X-rays "to look at very, very small objects with really high resolution," Michael Bogan, a staff scientist at the Department of Energy's SLAC National Accelerator Laboratory, told me today.

    The proof-of-concept studies using the world's first hard X-ray free-electron laser — the Linac Coherent Light Source, located at the lab — were published in this week's issue of the journal Nature.

    The research was led by Henry Chapman of the Center for Free Electron Laser Science at the German national laboratory DESY and Janos Hajdu of Sweden's Uppsala University, together with a team of more than 80 researchers, including Bogan, from 21 institutions.

    "The LCLS beam is a billion times brighter than previous X-ray sources, and so intense it can cut through steel," Chapman said in a news release. "Yet these incredible X-ray bursts are used with surgical, microscopic precision and exquisite control, and this is opening whole new realms of scientific possibilities."

    The technique opens up pathways that could lead to new drugs designed to target specific proteins,  to new views of the internal structure of viruses, or to new insights into why plants are so efficient at converting sunlight into energy.

    Diffraction before destruction
    Until now, making X-ray images of such tiny objects was difficult because conventional X-rays destroyed the object being imaged before any useful structural data was recorded.

    The hard X-ray free-electron laser gets around this problem by shooting femtosecond-long pulses at the object. A femtosecond is one-quadrillionth of a second. Think a few millionths of a billionth of a second long. "And they are coming in so quickly that the X-rays scatter off that object and we capture them on a camera — and then the object explodes," Bogan explained.

    This concept is known as "diffraction before destruction," he said.

    Since the objects are destroyed soon after they are hit by the laser, to create the images, researchers send streams of the objects into the path of the X-ray beam.

    Protein structure
    In the protein structure experiment, the team targeted Photosystem I, a protein found in the membrane of plant cells that plays a key role in converting sunlight into energy.

    To make the image of the protein's structure, they squirted millions of nanocrystals containing copies of Photosystem I in a liquid jet 10 times thinner than a hair across the X-ray beam. The laser pulses hit the crystals at various angles and scattered into the detector, forming the patterns needed to reconstitute the images.

    The team then combined 10,000 of the 3 million snapshots into the known molecular structure of Photosystem I. In a few weeks, a second round of the experiment will use even shorter pulses, potentially allowing the team to get "single-atom resolution of these membrane structures. This will be really, really, really incredible," Bogan said.

    Some researchers will use the technology to understand the structure of proteins that they want to target with new drugs, he noted. The Department of Energy has, well, energy on its mind.

    "We're trying to understand how these Photosystem membrane proteins can actually convert the sun's light into energy, and so the next targets are to start looking at other proteins involved in this process such as Photosystem II, which is another unsolved membrane protein," Bogan said.

    If researchers can understand how plants convert sunlight into energy so efficiently, they may be able to reverse-engineer the process, he added. "Just having the basic understanding of how this is working would be tremendously useful."

    Amoeba virus
    For the virus experiment, the researchers sprayed an aerosol stream of virus particles into the beam, allowing them to make single-shot portraits of the Mimivirus, the world's largest known virus, which infects amoebas.

    The images show the 20-sided structure of the virus' outer coat and an area of denser material inside, which may represent genetic material. The team speculates that shorter, brighter pulses focused to a smaller area should improve the resolution of the images to reveal details as small as a nanometer.

    "This is a brand new way to look at a biological object," team member Jean-Michel Claverie, director of the Structural & Genomic Information Lab in Marseille, said in a news release. "This will allow us address not only questions related to the internal structure of the virus, but its intrinsic variability from one individual virus particle to the next — a microscopic variability that might play a fundamental role in evolution."

    Bogan noted that the realm of research opened up by this new imaging technique is just now becoming apparent. He likened it to being handed a computer that is more than a billion times faster than what's currently available.

    "You couldn't even imagine what you would be able to do with this thing because it would be so powerful," he told me. "And that's really where we are right now. We are at the very beginning of this capability, and these are the first demonstrations of the type of biological experiments we'll be doing with them."

    More stories on X-rays and lasers:

    John Roach is a contributing writer for msnbc.com. Connect with the Cosmic Log community by hitting the "like" button on the Cosmic Log Facebook page or following msnbc.com's science editor, Alan Boyle, on Twitter (@b0yle).

  • Monuments immortalized ... virtually

    A laser scanning team has just finished up work on Mount Rushmore, kicking off the latest phase of a project to create a digital record of the world’s great monuments.

    Two weeks of arduous 3-D scanning wrapped up just today, said Elizabeth Lee, director of projects and development for California-based CyArk. "It was a really successful project," she told me. But it wasn't without its challenges. Rope teams had to clamber down the face of the mountainside in South Dakota's Black Hills to record the ins and outs of the 60-foot-long presidential faces.

    The weather didn't help. "We had everything," Lee said. "We had 90-degree heat, where people got sunburned. We had snow that kept us from working for two days. Yesterday, there were hailstorms and floods and tornadoes."

    But it's all worth it: When all the readings are compiled, the partners in the project - including the National Park Service - will have the most accurate virtual rendering ever made of the decades-old monument.

    Between 1927 and 1941, the faces of Presidents George Washington, Thomas Jefferson, Abraham Lincoln and Theodore Roosevelt were sculpted by hundreds of workers using dynamite and chisels. This time around, the workers had to take care not to chip away at the rock. In addition to using more traditional surveying techniques, Lee and her teammates set up laser-scanning equipment on custom-made tripods, and bounced laser light harmlessly off the sculpture's nooks and crannies. CyArk explains how laser scanning works in detail.

    Lincoln face

    Laser scanners capture millions of data points to create a high-resolution rendering of Abraham Lincoln's face. (Photo by Kacyra Family Foundation / CyArk)

    During today's final round of measurements, a tripod was positioned on Washington's eyebrow and just above his chin to scan the parts of the face that couldn't be accurately measured from the ground or from the top of George's head, Lee said.

    The product of all this work will be a high-definition 3-D computer representation of the famous faces. The park service can use the database to create picture-perfect representations of Mount Rushmore for scale models, online virtual tours and perhaps a holographic display at the visitor center. And in case anything happens to the monument - ranging from normal wear and tear to a catastrophic crumbling - the 3-D data can be used to guide repairs.

    CyArk sees the Rushmore project as part of its grand plan is to create virtual records for 500 heritage sites around the world in five years. "We haven't set an official start date yet," Lee said. Nevertheless, the venture is getting an early start toward the 500-site goal by carrying out more than 30 preservation projects at places ranging from Angkor Wat to the ancient Egyptian capital of Thebes to San Francisco's Presidio.

    Lee said CyArk is the brainchild of engineer/entrepreneur Ben Kacyra, who immigrated to the United States from Iraq in 1964 and helped develop the 3-D laser-scanning technology that was used on Mount Rushmore. In the past, laser scanning has been put to use in such applications as "Star Wars" anti-missile systems and oil-prospecting operations. Kacyra is using some of his fortune to show that "the technology that he developed could be used for heritage purposes" as well, Lee said.

    In an Associated Press interview, Kacyra said he was pleased to see Rushmore added to the laser-scan list. "Being an immigrant, the monument is a symbol that I cherish," he said. "It's a symbol for the U.S., and a symbol for the world."

    Rushmore was CyArk's first international project done in collaboration with the "Scottish 10," a heritage-mapping effort that involves Historic Scotland and Glasgow School of Art. There are still more groups out there scanning history. Here are just a few of the latest adventures to come to light:

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