NASA captures new images of large asteroid passing Earth

ScienceDaily (Nov. 8, 2011) — NASA's Deep Space Network antenna in Goldstone, Calif. has captured new radar images of Asteroid 2005 YU55 passing close to Earth.

The asteroid safely will safely fly past our planet slightly closer than the moon's orbit on Nov. 8. The last time a space rock this large came as close to Earth was in 1976, although astronomers did not know about the flyby at the time. The next known approach of an asteroid this size will be in 2028.

The image was taken on Nov. 7 at 11:45 a.m. PST (2:45 p.m. EST/1945 UTC), when the asteroid was approximately 860,000 miles (1.38 million kilometers) away from Earth. Tracking of the aircraft carrier-sized asteroid began at Goldstone at 9:30 a.m. PDT on Nov. 4 with the 230-foot-wide (70-meter) antenna and lasted about two hours, with an additional four hours of tracking planned each day from Nov. 6 -- 10.

Radar observations from the Arecibo Planetary Radar Facility in Puerto Rico will begin Nov. 8, the same day the asteroid will make its closest approach to Earth at 3:28 p.m. PST (6:28 p.m. EST/1128 UTC).

The trajectory of asteroid 2005 YU55 is well understood. At the point of closest approach, it will be no closer than 201,700 miles (324,600 kilometers) as measured from the center of Earth, or about 0.85 times the distance from the moon to Earth. The gravitational influence of the asteroid will have no detectable effect on Earth, including tides and tectonic plates. Although the asteroid is in an orbit that regularly brings it to the vicinity of Earth, Venus and Mars, the 2011 encounter with Earth is the closest it has come for at least the last 200 years.

NASA detects, tracks and characterizes asteroids and comets passing close to Earth using both ground- and space-based telescopes. The Near-Earth Object Observations Program at NASA's Jet Propulsion Laboratory in Pasadena, Calif., commonly called "Spaceguard," discovers these objects, characterizes some of them, and plots their orbits to determine if any could be potentially hazardous to our planet. JPL manages the Near-Earth Object Program Office for NASA's Science Mission Directorate in Washington.

The new radar images are online at: http://www.nasa.gov/mission_pages/asteroids/multimedia/yu55-20111107.html .

For more information about asteroids and near-Earth objects, visit: http://www.jpl.nasa.gov/asteroidwatch .

More information about asteroid radar research is available online at: http://echo.jpl.nasa.gov/ .

For more information about NASA's Deep Space Network, visit: http://deepspace.jpl.nasa.gov/dsn .

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New weapon against cancer: Microwaves can be used to create medical images

ScienceDaily (Oct. 25, 2011) — A research team from Chalmers University of Technology has developed new techniques of cancer diagnosis and treatment with the aid of microwaves, which could play a pioneering role in the battle against cancer. These techniques could save many lives and are more effective, less invasive and simpler than currently available alternatives. Clinical studies are now being planned.

The Chalmers team expects to be able to test two different techniques on patients within the next six months. One method is an alternative to mammography, i.e. using X-rays to detect breast cancer. The other aims to treat tumours in the head and neck by heating the cancer cells.

Microwaves can be used to create medical images -- a new technique known as microwave tomography. Andreas Fhager, Associate Professor of Biomedical Electromagnetics, has developed a system to detect breast cancer with the new technique. He points out that the method has several advantages over mammography.

"We obtain three-dimensional images showing significantly better contrast between healthy and malignant tissue compared to X-rays. That makes it easier to detect even really small tumours that may currently be obscured by healthy tissue, thus creating the preconditions for much more reliable diagnosis."

"Unlike X-rays, the technique also emits negligible doses of non-ionising radiation -- less than a hundredth of the radiation to which you are exposed when talking on a mobile phone."

The idea is to use the technique in conjunction with a treatment couch, equipped with holes for the breasts, to which the thirty or so antennas required by the examination are connected. It should be considerably more comfortable for patients than mammography. The method is also much less expensive, not only because microwave equipment is not so costly, but also because the clearer images make interpretation easier for the doctors.

In the second Chalmers project, the microwaves are actually used to destroy the tumours by heating them, a process known as hyperthermia. Clinical studies have shown that treatment with conventional radiotherapy and chemotherapy in combination with hyperthermia may double the long-term ability to cure certain forms of cancer, such as cervical cancer and soft-tissue sarcoma.

"We are now developing a new hyperthermia system that can reach deep-seated tumours in the head and neck with high accuracy," says Hana Dobšícek Trefná, a PhD in Biomedical Engineering. "In this way, higher temperatures can be reached in the tumour without affecting the surrounding tissue."

With time, the Chalmers team hope to be able to combine both methods. As soon as a tumour is detected, the already connected antennas could be used to start treating the tumour directly while at the same time monitoring that the right tissue is heated up. The method should also be applicable for other parts of the body than breasts, head and neck.

Theranostics -- the treatment and diagnosis of diseases in a single system -- is a growing area of research, and the Chalmers team believe that microwaves have great potential in the field. The underlying microwave technology is already being used in the "Strokefinder," a helmet that can distinguish between blood clots and bleeding in the brain. The Strokefinder is currently undergoing clinical trials at Sahlgrenska Hospital.

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Optical microscope without lenses produces high-resolution 3-D images on a chip

ScienceDaily (Apr. 25, 2011) — UCLA researchers have redefined the concept of a microscope by removing the lens to create a system that is small enough to fit in the palm of a hand but powerful enough to create three-dimensional tomographic images of miniscule samples.

The advance, featured in the early online edition of the journal Proceedings of the National Academy of Sciences, represents the first demonstration of lens-free optical tomographic imaging on a chip, a technique capable of producing high-resolution 3-D images of large volumes of microscopic objects.

"This research clearly shows the potential of lens-free computational microscopy," said Aydogan Ozcan, senior author of the research and an associate professor of electrical engineering at UCLA's Henry Samueli School of Engineering and Applied Science. "Wonderful progress has been made in recent years to miniaturize life-sciences tools with microfluidic and lab-on-a-chip technologies, but until now optical microscopy has not kept pace with the miniaturization trend."

An optical imaging system small enough to fit onto an opto-electronic chip provides a variety of benefits. Because of the automation involved in on-chip systems, scientific work could be sped up significantly, which might have a great impact in the fields of cell and developmental biology. In addition, the small size not only has great potential for miniaturizing systems but also leads to cost savings on equipment.

The optical microscope, invented more than 400 years ago, has tended to grow larger and more complex as it has been modified to image ever-smaller objects with better resolution. To address this lack of progress in miniaturization, Ozcan's research group -- with graduate student Serhan Isikman and postdoctoral scholar Waheb Bishara as lead researchers -- developed the new tomographic microscopy platform through the next evolution of a lens-free imaging technology the group created and has been improving for years.

Ozcan, a researcher at the California NanoSystems Institute at UCLA, makes the analogy that a traditional optical microscope is like a huge set of pipes delivering content, in the form of images, to the user. Over years of development, bottlenecks occur that impede further improvement. Even if one part of the system -- that is, one bottleneck -- is improved, other bottlenecks keep that improvement from being fully realized. Not so with the lens-free system, according to Ozcan.

"Lens-free imaging removes the pipes altogether by utilizing an entirely new design," he said.

The system takes advantage of the fact that organic structures, such as cells, are partially transparent. So by shining a light on a sample of cells, the shadows created reveal not only the cells' outlines but details about their sub-cellular structures as well.

"These details can be captured and analyzed if the shadow is directed onto a digital sensor array," Isikman said. "The end result of this process is an image taken without using a lens."

Ozcan envisions this lens-free imaging system as one component in a lab-on-a-chip platform. It could potentially fit beneath a microfluidic chip, a tool for the precise control and manipulation of sub-millimeter biological samples and fluids, and the two tools would operate in tandem, with the microfluidic chip depositing and subsequently removing a sample from the lens-free imager in an automated, or high-throughput, process.

The platform's 3-D images are created by rotating the light source to illuminate the samples from multiple angles. These multiple angles also allow the system to utilize tomography, a powerful imaging technique. Through the use of tomography, the system is able to produce 3-D images without sacrificing resolution.

"The field of view of lens-based microscopes is limited because the lens focuses on a narrow area of a sample," Bishara said. "A lens-free microscope has both a much larger field of view and depth of field because the imaging is done by the digital sensor array and is not constrained by a lens."

The research was funded by grants from the National Science Foundation, the U.S. Office of Naval Research and the National Institutes of Health and was also supported by the Gates Foundation and the Vodafone Americas Foundation.

For more information on the Ozcan research group, visit http://innovate.ee.ucla.edu/.

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The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by University of California - Los Angeles. The original article was written by Mike Rodewald.

Journal Reference:

S. O. Isikman, W. Bishara, S. Mavandadi, F. W. Yu, S. Feng, R. Lau, A. Ozcan. Lens-free optical tomographic microscope with a large imaging volume on a chip. Proceedings of the National Academy of Sciences, 2011; DOI: 10.1073/pnas.1015638108

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