Articles from January 2015

How To Bend Acoustic and Elastic Waves

Sound waves passing through the air, objects that break a body of water and cause ripples, or shockwaves from earthquakes all are considered “elasticwaves. These waves travel at the surface or through a material without causing any permanent changes to the substance’s makeup. Now, engineering researchers at the University of Missouri (MU) have developed a material that has the ability to control these waves, creating possible medical, military and commercial applications with the potential to greatly benefit society.
acoustic waves
Methods of controlling and manipulating subwavelength acoustic and elastic waves have proven elusive and difficult; however, the potential applications — once the methods are refined—are tremendous,” said Guoliang Huang, associate professor of mechanical and aerospace engineering in the College of Engineering at MU. “Our team has developed a material that, if used in the manufacture of new devices, could have the ability to sense sound and elastic waves. By manipulating these waves to our advantage, we would have the ability to create materials that could greatly benefit society—from imaging to military enhancements such as elastic cloaking — the possibilities truly are endless.

Doubling The Electrical Output Of Solar Cells

One challenge in improving the efficiency of solar cells is that some of the absorbed light energy is lost as heat. So scientists have been looking to design materials that can convert more of that energy into useful electricity. Now a team from the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory and Columbia University has paired up polymers that recover some of that lost energy by producing two electrical charge carriers per unit of light instead of the usual one.

solar cell
Critically, we show how this multiplication process can be made efficient on a single molecular polymer chain,” said physicist Matthew Sfeir, who led the research at Brookhaven Lab’s Center for Functional Nanomaterials (CFN), a DOE Office of Science User Facility. Having the two charges on the same molecule means the light-absorbing, energy-producing materials don’t have to be arrayed as perfect crystals to produce extra electrical charges. Instead, the self-contained materials work efficiently when dissolved in liquids, which opens the way for a wide range of industrial scale manufacturing processes, including “printingsolar-energy-producing material like ink.

The research is published as an Advance Online Publication in Nature Materials, January 12, 2015.


300 Colors Rainbow Polymer May Detect Disease

University at Buffalo (UB) engineers have developed a one-step, low-cost method to fabricate a polymer with extraordinary properties: When viewed from a single perspective, the polymer is rainbow-colored, reflecting many different wavelengths of light.
Used as a filter for light, this material could form the basis of handheld multispectral imaging devices that identify the “true color” of objects examined.
Such portable technology could have applications in a wide range of fields, from home improvement, like matching paint colors, to biomedical imaging, including analyzing colors in medical images to detect disease,” said UB Vice President for Research and Economic Development Alexander N. Cartwright, one of the UB researchers who led the study.
The ease of producing the polymer could make it feasible to develop small devices that connect with cell phones to conduct multispectral imaging, said Qiaoqiang Gan, a UB assistant professor of electrical engineering and another member of the research team.
rainbowA rainbow-colored grating, about 25 millimeters wide, under sunlight. Enlarged microscope images show the graded surface, with the black bars indicating a length of 10 micron

Our method is pretty low-cost, and because of this and the potential cell phone applications, we feel there is a huge market for improving clinical imaging in developing countries,” Gan said.
Because the colors of the rainbow filter are produced as a result of the filter’s surface geometry, and not by some kind of pigment, the colors won’t fade over time. (It’s the same principle that gives color to the wings of butterflies and feather of peacocks.)
Cartwright and Gan’s team reported on their polymer fabrication technique online in Advanced Materials.

Liver Cancer: NanoDiamonds Eliminate Resistant Stem Cells

A study led by the National University of Singapore (NUS) found that attaching chemotherapy drug Epirubicin to nanodiamonds effectively eliminates chemoresistant cancer stem cells. The findings were first published online in ACS Nano, the official journal of the American Chemical Society.
liver cancer

The research team, led by Assistant Professor Edward Chow, Junior Principal Investigator at the Cancer Science Institute of Singapore (CSI Singapore) at NUS, demonstrated the use of nanotechnology to repurpose existing chemotherapy drugs as effective agents against chemoresistant cancer stem cells. Chemoresistance, which is the ability of cancer cells to escape chemotherapy treatment, is a primary cause of treatment failure in cancer. Cancer stem cells, a type of cancer cell which initiates the formation of tumours, are commonly found to be more resistant to chemotherapy than the rest of the bulk tumour, which can lead to cancer recurrence following chemotherapy treatment. As such, there is intense interest in developing new drugs or treatment strategies that overcome chemoresistance, particularly in cancer stem cells.

In this study, widely-used chemotherapy drug Epirubicin was attached to nanodiamonds, carbon structures with a diameter of about five nanometres, to develop a nanodiamond-Epirubicin drug delivery complex (EPND). The researchers found that while both standard Epirubicin as well as EPND were capable of killing normal cancer cells, only EPND was capable of killing chemoresistant cancer stem cells and preventing secondary tumour formation in xenograft models of liver cancer.


Super Smart Keyboard Replaces Passwords

By analyzing such parameters as the force applied by key presses and the time interval between them, a new self-powered non-mechanical intelligent keyboard could provide a stronger layer of security for computer users. Designed by the Professor Zhong Lin Wang and his team from Georgia Tech, the self-powered device generates electricity when a user’s fingertips contact the multi-layer plastic materials that make up the device.

By analyzing such parameters as the force applied by key presses and the time interval between them, a new self-powered non-mechanical intelligent keyboard could provide a stronger layer of security for computer users
“This intelligent keyboard changes the traditional way in which a keyboard is used for information input,” said Zhong Lin Wang, a Regents professor in the School of Materials Science and Engineering at the Georgia Institute of Technology. “Every punch of the keys produces a complex electrical signal that can be recorded and analyzed.

Conventional keyboards record when a keystroke makes a mechanical contact, indicating the press of a specific key. The intelligent keyboard records each letter touched, but also captures information about the amount of force applied to the key and the length of time between one keystroke and the next. Such typing style is unique to individuals, and so could provide a new biometric for securing computers from unauthorized use.


Anti reflective Solar Cells Boost Energy Output

Reducing the amount of sunlight that bounces off the surface of solar cells helps maximize the conversion of the sun’s rays to electricity, so manufacturers use coatings to cut down on reflections. Now scientists at the U.S. Department of Energy’s Brookhaven National Laboratory show that etching a nanoscale texture onto the silicon material itself creates an antireflective surface that works as well as state-of-the-art thin-film multilayer coatings. The surface nanotexture … drastically cut down on reflection of many wavelengths of light simultaneously.
Their method, described in the journal Nature Communications and submitted for patent protection, has potential for streamlining silicon solar cell production and reducing manufacturing costs. The approach may find additional applications in reducing glare from windows, providing radar camouflage for military equipment, and increasing the brightness of light-emitting diodes.

antireflection square of siliconA closeup shows how the nanotextured square of silicon completely blocks reflection compared with the surrounding silicon wafer
For antireflection applications, the idea is to prevent light or radio waves from bouncing at interfaces between materials,” said physicist Charles Black, who led the research at Brookhaven Lab’s Center for Functional Nanomaterials (CFN), a DOE Office of Science User Facility.
The issue with using such coatings for solar cells,” he said, “is that we’d prefer to fully capture every color of the light spectrum within the device, and we’d like to capture the light irrespective of the direction it comes from. But each color of light couples best with a different antireflection coating, and each coating is optimized for light coming from a particular direction. So you deal with these issues by using multiple antireflection layers. We were interested in looking for a better way.”


Artificial Heart: Patient Came Back Home For A New Life

Five months after his surgery in Nantes, the second French patient who received CARMAT artificial heart is in good health, after he came back home.

For the first time, we are not talking only of survival but of a “new life“, says the Dr Carpentier in charge of the recovery. The second patient who received an artificial heart on 5 August in Nantes, returned to his family, free of his movements. He just needs to carry a bag of three pounds, similar to a laptop and has to charge its batteries every 4 to 5 hours.
artificial heart CARMAT
This is good news even to the father of the French artificial heart – Professor Carpentier – who speaks of “miracle” in front of a man walking better than he does. In late October, Prof. Carpentier indicated that his patient could already exercise on a bike. Return to a “normal” life, autonomous, that is the final purpose and this is why the artifical heart has been designed.

Bionic Arm At Low Price

Stella Azambullo lost her right arm in an industrial accident. Now after years of limited dexterity, she’s testing this low-cost bionic arm which helps her perform everyday tasks.

bionic arm 2The flexible claw-like hand has a thumb, index and middle finger. Covered in a skin-like glove, it looks indistinguishable from Stella’s real arm. Sensors in the bionic limb detect electric signals from moving muscles. The signal is relayed to a motor that opens and closes the hand. Project engineer Luciana Joliat teaches patients like Stella how to use the device

I work directly with the patient and the stump to look for the strongest myoelectric signals before voluntary contractions. I train the patient to activate two muscle groups to activate the opening and closing sensors, to direct the prosthetic and make open and close, says Luciana Joliat, bioengineer in charge of the patient. Stella can now perform tasks that were impossible with her clunkier mechanical prostheses.
I’m doing very well. I’m happy to be able to do lots of things again, mainly things around the house, and also I’m happy aesthetically. Being able to go back to work has really helped me. I feel good and can move forward and start doing what I used to do“, comments Stella.
Developers from the company Bioparx Health Technology (Argentina) underscore that it is Latin America’s first budget bionic arm with sensors that respond to nerve impulses. Bioparx director and enginneer, Ricardo Rodriguez says the device is more affordable than others on the market.”We’ve achieved a cost around 50 percent less compared to similar models that we’re competing with“.


Super Battery For Electric Vehicles

An ultra-thin nanomaterial is at the heart of a major breakthrough by scientists from the University of Waterloo (Canada) who are in a global race to invent a cheaper, lighter and more powerful rechargeable battery for electric vehicles. Chemistry Professor Linda Nazar and her research team in the Faculty of Science at the University of Waterloo have announced a breakthrough in lithium-sulphur battery technology in a recent issue of Nature Communications.

Their discovery of a material that maintains a rechargable sulphur cathode helps to overcome a primary hurdle to building a lithium-sulphur (Li-S) battery. Such a battery can theoretically power an electric car three times further than current lithium-ion batteries for the same weight – at much lower cost.
Sulphur as a battery material is extremely abundant, relatively light, and very cheap.

electric car
This is a major step forward and brings the lithim-sulphur battery one step closer to reality,” said Nazar, who also holds the Canada Research Chair in Solid State Energy Materials.
You have to focus on the a fundamental understanding of the phenomenon before you can develop new, advanced materials,” said Nazar.

They found that the oxygenated surface of the ultrathin MnO2 nanosheet chemically recycles the sulphides in a two-step process involving a surface-bound intermediate, polythiosulfate. The result is a high-performance cathode that can recharge more than 2000 cycles.


How To Extract Tumor Cells From Blood

An international group led by scientists at UCLA’s California NanoSystems Institute has developed a new method for effectively extracting and analyzing cancer cells circulating in patients’ blood. Circulating tumor cells are cancer cells that break away from tumors and travel in the blood, looking for places in the body to start growing new tumors called metastases. Capturing these rare cells would allow doctors to detect and analyze the cancer so they could tailor treatment for individual patients. In his laboratory at the UCLA California NanoSystems Institute, Hsian-Rong Tseng, a professor of molecular and medical pharmacology, used a device he invented to capture circulating tumor cells from blood samples.

The device, called the NanoVelcro Chip, is a postage-stamp–sized chip with nanowires that are 1,000 times thinner than a human hair and are coated with antibodies that recognize circulating tumor cells. When 2 milliliters of blood are run through the chip, the tumor cells stick to the nanowires like Velcro.
Now Tseng and his colleagues have developed a thermoresponsive NanoVelcro purification system, which enables them to raise and lower the temperature of the blood sample to capture (at 37 degrees Celsius) and release (at 4 degrees Celsius) circulating tumor cells at their optimal purity.

capture cancer cells

With our new system, we can control the blood’s temperature — the way coffeehouses would with an espresso machine — to capture and then release the cancer cells in great purity, ” said Tseng, who is also a member of UCLA’s Jonsson Comprehensive Cancer Center.

The study, which was published online by the journal ACS Nano, brought together an interdisciplinary team from the U.S., China, Taiwan and Japan.


How To Early Detect Heart Attacks

NYU Polytechnic School of Engineering professors have been collaborating with researchers from Peking University on a new test strip that is demonstrating great potential for the early detection of certain heart attacks.

Kurt H. Becker, a professor in the Department of Applied Physics, and WeiDong Zhu, a research associate professor in the Department of Mechanical Engineering, are helping develop a new colloidal gold test strip for cardiac troponin I (cTn-I) detection. The new strip uses microplasma-generated gold nanoparticles (AuNPs) and shows much higher detection sensitivity than conventional test strips. The new cTn-I test is based on the specific immune-chemical reactions between antigen and antibody on immunochromatographic test strips using AuNPs.
gold heart
Compared to AuNPs produced by traditional chemical methods, the surfaces of the gold nanoparticles generated by the microplasma-induced liquid chemical process attract more antibodies, which results in significantly higher detection sensitivity.


Cancer: If It Glows, Cut It Out Or Kill It !

Researchers at Oregon State University (OSU) have developed a new way to selectively insert compounds into cancer cells – a system that will help surgeons identify malignant tissues and then, in combination with phototherapy, kill any remaining cancer cells after a tumor is removed. It’s about as simple as, “If it glows, cut it out.” And if a few malignant cells remain, they’ll soon die.
Technology such as this, scientists said, may have a promising future in the identification and surgical removal of malignant tumors, as well as using near-infrared light therapies that can kill remaining cancer cells, both by mild heating of them and generating reactive oxygen species that can also kill them.
Scientists have developed a a new method that sees cancer cells glow, potentially allowing for more accurate surgeries
This is kind of a double attack that could significantly improve the success of cancer surgeries,” said Oleh Taratula, an assistant professor in the OSU College of Pharmacy.
With this approach, cancerous cells and tumors will literally glow and fluoresce when exposed to near-infrared light, giving the surgeon a precise guide about what to remove,” Taratula said. “That same light will activate compounds in the cancer cells that will kill any malignant cells that remain. It’s an exciting new approach to help surgery succeed.”

The findings, published in the journal Nanoscale, have shown remarkable success in laboratory animals. The concept should allow more accurate surgical removal of solid tumors at the same time it eradicates any remaining cancer cells. In laboratory tests, it completely prevented cancer recurrence after phototherapy.