Wednesday, January 23, 2008

A Cheaper Battery for Hybrid Cars

New lead-acid batteries could achieve high performance.

Still going: Tests of a Honda Insight equipped with a novel type of lead-acid battery showed that the hybrid vehicle can run more than 100,000 miles using the new technology.
Credit: Advanced Lead-Acid Battery Consortium

The future market for hybrid-electric vehicles, at least those that are affordable, isn't necessarily paved with lithium. Researchers in Australia have created what could be called a lead-acid battery on steroids, capable of performing as well as the nickel-metal hydride systems found in most hybrid cars but at a fraction of the cost.

The so-called UltraBattery combines 150-year-old lead-acid technology with supercapacitors, electronic devices that can quickly absorb and release large bursts of energy over millions of cycles without significant degradation. As a result, the new battery lasts at least four times longer than conventional lead-acid batteries, and its creators say that it can be manufactured at one-quarter the cost of existing hybrid-electric battery packs.

In the United Kingdom last week, a Honda Insight hybrid powered by the UltraBattery system surpassed 100,000 miles on a test track. "The batteries were still in perfect condition at the end of the test," says David Lamb, who heads up low-emission transport research at the Commonwealth Scientific and Industrial Research Organisation (CSIRO), Australia's national science agency. "What we've got is a lead-acid battery that is nice and cheap but can perform as well as, or better than, the nickel-metal hydride technology, which we know is very expensive."

Lead-acid batteries, invented by French physicist Gaston Plante in 1859, don't get much respect these days, despite being a crucial fixture under the hood of most vehicles. They contain lead, so environmentalists don't like them. They're heavy for the energy they store--a bad trait for mobile applications. And they degrade easily if not cycled properly. Indeed, there have been no major advances in the technology over the decades.

Meanwhile, a newer generation of batteries--most notably lithium-ion ones--are capturing the attention of investors and automakers. "Many have tried to improve the lead-acid battery, but the improvements were usually not that great or worth the added cost," says Malcolm Shemmans, founder and president of BET Services, a provider of battery-testing services to the auto industry.

To compensate for some of the shortcomings of lead-acid technology, many in the past have tried to complement the batteries with supercapacitors. In the late 1990s, for example, Lamb helped design two hybrid cars that used a 60-volt lead-acid pack and a separate 150-volt supercapacitor pack. The lead-acid system allowed the vehicles to drive in all-electric mode in the city, while the supercapacitors gave the cars the jolt that was needed for acceleration and the ability to quickly absorb energy from braking.

The cars worked well, but all the power electronics that were needed to control the two power systems were heavy and prohibitively expensive. Instead of treating the lead-acid batteries and supercapacitors as separate systems, Lamb's team decided to eliminate the need for all external electronics and instead build the supercapacitors directly into the battery. Essentially, one of the plates (the negative electrode) in the lead-acid battery was made half of lead and half of carbon, turning the battery into a supercapacitor-lead-acid hybrid.

CSIRO brought the design to Japanese battery manufacturer Furukawa Battery Company, which saw potential in the technology. After three years of collaboration, the two organizations determined that they could manufacture the UltraBattery much like conventional lead-acid batteries and at similar cost.

Meanwhile, Axion Power International, in New Castle, PA, has also developed a new type of lead-acid battery. Edward Buiel, chief technical officer with Axion, says that lead-acid batteries can play a significant role in the future of transportation and energy supply. Unfortunately, he adds, the automakers don't see the potential. "If you're not lithium-ion or nickel-metal hydride, they're not interested. It's frustrating."

Buiel says that the typical cost of a nickel-metal hydride power pack is $2,000, and close to $5,000 retail. "A comparable lead-acid could be in the range of $1,000 in low volume, and significantly less in high volume," he says. "It's a battery where the consumer could see enough fuel savings for a payback in a year or two."

Despite the reluctance of the auto industry to embrace the technology, Lamb is convinced that by 2010 there will be some Japanese-made hybrid cars on the market offering the UltraBattery option.

However, Axion might have something to say about it. "We definitely think this technology is an excellent choice for hybrid-electric vehicles," says Buiel. "There's a lot of intellectual property in this area, and most of it is owned by Axion. Obviously, if we feel somebody violates our patent, we will defend that vigorously." He says that Axion plans to launch a demonstration project in North America this year that will test dozens of hybrid vehicles retrofitted with its lead-carbon batteries.

High-Contrast X-Rays

Dark-field x-ray imaging could make for more-accurate mammograms and better security screens.

Hot wings: A new x-ray imaging technique (bottom) relies on information about how a sample scatters the radiation, providing a higher contrast image of the bones in a chicken wing than conventional x-ray imaging (top) does. Conventional x-ray imaging relies on information about how the wing absorbs radiation.
Credit: Franz Pfeiffer, EPFL

Swiss researchers have demonstrated the practicality of a new high-resolution x-ray imaging technique that reveals fine structures that are invisible using conventional techniques. Dark-field x-ray imaging can be used to generate highly detailed images of bones and to distinguish between substances that look identical in conventional x-ray images, such as explosives and cheese. The researchers are now investigating whether their approach might also increase the resolution of medical imaging techniques such as mammograms and computed-tomography (CT) scans.

Franz Pfeiffer, assistant professor of physics at Ecole Polytechnique Fédérale de Lausanne, in Switzerland, who developed the new technique, compares conventional x-ray images with shadows. Such images rely on information about how much radiation is absorbed as it passes through a sample, such as a patient's limb. But more-complex interactions are happening, says Pfeiffer, and the more information that can be gleaned about these interactions, the better the contrast of the images. Dark-field imaging measures how a sample scatters light.

"These guys are showing that you can do things with x-rays that were only thought practical optically [with visible light]," says Richard Lanza, a senior research scientist at MIT's department of nuclear science and engineering.

Previously, researchers including Pfeiffer had demonstrated dark-field imaging using a large, expensive particle accelerator called a synchrotron as an x-ray source. Synchrotrons provide very bright, finely focused beams of x-rays. Such a powerful source was necessary because the inefficient crystal optics used to focus the x-rays onto the sample could only cope with a narrow spectrum of wavelengths.

To replace the inefficient crystal optics, Pfeiffer developed silicon filters that work with the full spectrum of rays generated by low-power, conventional x-ray tubes. These filters are flat discs of silicon etched with 20-micrometer-long slits, some of which are filled with gold. To generate scattering images, these grates are placed between the x-ray source and the sample, and between the sample and the detector.

"Small structures like micro-cracks show up nicely in these images because they scatter radiation quite a bit," says Pfeiffer. This suggests that the images could be useful for detecting osteoporosis or for finding flaws in mechanical structures such as turbines.

"Edges and boundaries are more clear in the dark-field images," says Elizabeth Brainerd, an evolutionary biologist at Brown University, who uses x-rays to study the biomechanics of bones. (See "Catching Evolution on the Run.") It can be difficult to distinguish small bones and joints in conventional x-rays. Brainerd agrees that dark-field images could be useful for detecting small fractures and bone spurs in patients, and she's excited about the possibility of extending Pfeiffer's technique to three-dimensional CT scans.

Pfeiffer's approach could be used to improve security systems too. Conventional x-ray imagers like those at airport-security checkpoints can't differentiate between many different kinds of materials--for example, chocolate and cheese appear identical to some explosives. But cheese and explosives scatter x-rays differently, so in Pfeiffer's dark-field images, the differences between the two materials are apparent.

Pfeiffer has already begun making CT scans with conventional x-ray tubes using another contrast-enhancing technique he developed two years ago, called phase contrast. He says that he's currently working to incorporate gratings for dark-field imaging into conventional CT devices. He's also collaborating with researchers at the Center for Biomedical Imaging, an institute run by the University of Lausanne and the University of Geneva, to determine whether dark-field x-ray imaging can be used to tell healthy tissue from cancerous tissue. Cancers don't absorb x-rays very differently than healthy tissue does, so x-ray systems that rely on other properties, such as scattering, might make for better mammograms, for example. Lanza's group at MIT is also working to develop better cancer-detecting CT scanners that use a combination of absorption and refraction for contrast and also rely on nanofabricated gratings. (See "Changing the Physics behind X-Ray Imaging.")

Dark-field imaging has been used for more than 20 years to enhance contrast and resolution in conventional optical microscopes. But applying the contrast-enhancing techniques that work well with visible light to x-rays has taken a long time, says Pfeiffer. Such a system is only now possible thanks to advances in photolithography and many years of basic science research using synchrotrons, he says.

Pfeiffer envisions that future x-ray imaging systems will be like what light microscopes are today: they will incorporate many complementary systems for enhancing contrast--absorption, refraction, scattering--and doctors and researchers will be able to use whichever combination works best for a given sample.

Mixing Up the Immune System

Transplanting bone marrow along with kidneys reduces the risk of organ rejection.

Post-op progress: Kidney-transplant patients whose immune systems were primed with donor bone marrow didn't need long-term treatment with immune-suppressing drugs.
Credit: AJPhoto / Photo Researchers, Inc.

By performing bone-marrow transplants along with kidney transplants, doctors in Boston were better able to trick recipients' immune systems into accepting the new organs as if they were their own.

Even though the patients received donor kidneys that weren't a good match, most of them were successfully weaned off of immune-suppressing drugs about a year after their transplants. Normally, patients have to take the drugs, which can have serious side effects, for the rest of their lives.

"It's groundbreaking work," says John C. Magee, director of the Kidney Transplant Program at the University of Michigan, who was not involved in the study. "They've shown that you can reeducate the immune system."

The technique could be applied to other kinds of transplants and used in the treatment of autoimmune diseases, says Megan Sykes, one of many researchers who carried out the work at Massachusetts General Hospital. Sykes is the associate director of the hospital's Transplantation Biology Research Center.

The team has been working for about 20 years to outsmart the immune system by inducing tolerance to a donor organ. In this study, reported in this week's issue of the New England Journal of Medicine, the scientists transplanted bone marrow along with a mismatched kidney, giving patients a kind of hybrid immune system that blended elements of both the donor and the recipient.

Four out of five patients who received bone-marrow transplants in conjunction with kidney transplants didn't need long-term treatment with immune-suppressing drugs. The technique was not successful for the fifth patient, however: his body rejected the donor kidney. He was given a second--and successful--transplant according to conventional protocol.

Doctors try to match people with similar versions of the genes that play a crucial role in immune reactions to foreign tissue. This genetic region is known as the human leucocyte antigen (HLA) complex. But finding a good match isn't always possible, so doctors often use a mismatched kidney and put the patient on immunosuppressive drugs to reduce the risk of rejection. The patients in the study, whose ages ranged from 22 to 46, were all suffering from advanced kidney disease and were unable to find living donors who were a very good tissue match. They received kidneys from family members who were HLA mismatched.

Before the surgery, the transplant team gave the patients drugs to deplete their bone marrow and suppress their immune response. After receiving new kidneys and then an intravenous infusion of bone marrow from their donors, the patients were kept in a relatively sterile environment to reduce their chance of infection, and to allow the bone marrow to regenerate and produce new immune cells that wouldn't attack the donor kidney.

In the months after their transplants, the patients in the study were treated with immunosuppressive drugs, but four out of five of them were able to discontinue those drugs between 9 and 14 months after surgery, and their new kidneys have been functioning well in the years since.

"I think it's quite exciting," Magee says. "It shows what's possible."

The researchers' approach could make transplants more feasible for people whose immune systems are already compromised by conditions like HIV, according to Yasir Qazi, medical director of the kidney and pancreas transplant program at the University of Southern California. (Qazi was not involved in the work.) Sykes says that the approach could potentially be used to treat autoimmune diseases such as type 1 diabetes. "It could have huge benefits," she says.

Although immunosuppressive drugs have revolutionized transplant medicine, they can increase the risk of cancer and heart disease. "Immunosuppression is great, because it makes kidneys work, but it's bad because it has lots of side effects," Magee says. "Some people say that in many ways, you're trading one disease for another. You still have to take lots of medicine and see a doctor."

The protocol developed by Sykes and her colleagues initially requires heavier drug treatment than that required with the standard kidney-transplant procedure, to allow the recipient's body to accept donated bone marrow as well as a donated kidney. But, she points out, the patient is only on the drugs for a limited time.

LG HDTV innovation for 2008

A total of 8 new lines of LCD TV's from the Korean manufacturer LG will showcase three main technological areas of development in 2008.

Building upon existing technological and design innovations LG are focusing on their super slim 1.7in LCD, wireless HDTV models and new LED backlighting technology to forge ahead in 2008.

The LG75 series is a 1.7in super slim design that according to an LG spokesperson, is the "epitome" of elegance. The LG75 comes with a unique 'rose red' tint within the "high-gloss" black finish.

The LG75's LED backlight is partitioned into 128 light-emitting diodes which enables local dimming to provide quick response to changing images. An advantage of local dimming ability is reduced energy consumption.

With 47in and 52in models, the LG71 Wireless LCD HDTV Series makes its debut in 2008. The built-in 802.11n Wireless System comes with separate wireless receiver giving a 50-foot radius giving the consumer more flexibility with the positioning of peripheral items.

LG have made a huge impact on the LCD TV market of late, and their latest innovation will surely add to their growing reputation as one of the leading LCD TV producers. LG's new found quality, performance and style is encapsulated by some of their more recent models such as the 32LB75, and their top end LY series of LCD TV's

Growth Hormone: Fountain of Youth or Early Killer?

A small population of dwarves in rural Ecuador could hold the answer.

Growth hormones: When growth hormone binds to its receptor, shown here (top), it activates a number of cellular pathways involved in growth and metabolism. When people have a nonfunctional version of the receptor--inactivating mutations are shown here in dark blue--they develop Laron syndrome, a type of dwarfism. Valter Longo, a biologist who studies aging at the University of Southern California, is pictured (bottom) with a person with Laron dwarfism. Longo plans to study how this mutation affects life span and the diseases of aging.
Credit: T. Blundell & N. Campillo, Wellcome Images (top), Valter Longo (bottom)

Growth hormone holds a conflicted status in the world of life extension. Some believe it turns back the clock, with evidence from humans suggesting that hormone treatment reduces fat and boosts muscle. But animal studies show the opposite: mice without growth hormone live significantly longer and are protected against cancer, one of the most deadly diseases of aging.

Valter Longo, a scientist at the University of Southern California, in Los Angeles, hopes to untangle this conundrum by studying an unusual group of people in Ecuador: those with a genetic mutation that renders them insensitive to growth hormone. "They are the largest population in the world that is growth-hormone deficient," says Longo. Studies of the group could provide a valuable window into whether growth-hormone depletion could, in fact, be used to extend longevity. The study could also shed light on how to develop drugs against the diseases of aging without introducing unintended side effects.

Growth hormone is a crucial protein produced by the pituitary that directs growth and cell division. People who lack the hormone or the ability to respond to it are extremely short, while those whose hormone levels dip in middle age, such as after damage to the pituitary, have an increased risk of cardiovascular disease. In mice, however, deficiency of the hormone seems to be beneficial. "In the mouse, the effect is major and striking," says Andrzej Bartke, a biologist at Southern Illinois University in Springfield, who is not involved in the project. "They seem protected from cancer and appear to have delayed aging by various measures. But there is almost no evidence that growth-hormone deficiency would extend life in humans."

The group Longo plans to study lives in the rural Loja province in the southern portion of Ecuador. These isolated mountain communities have a high rate of an otherwise rare condition known as Laron dwarfism. People with the condition lack a functioning version of the receptor that binds to growth hormone.They are small and obese, but little data exists on their longevity.

Children with the condition seem more susceptible to pneumonia and diarrhea, common scourges of poor rural communities, and they die at twice the rate of their unaffected siblings. Those who survive to adulthood typically have high cholesterol and triglycerides, risk factors for heart disease. Some die of heart disease, an uncommon occurrence in rural Ecuador, but preliminary reports suggest that Laron dwarves are protected from artherosclerosis, arterial hardening that can lead to heart attack. Adding to the puzzle is anecdotal evidence suggesting that they don't get cancer or type 2 diabetes. "It's a balance: if you turn down risk of cancer, you might turn up risk of heart disease," says Steven N. Austad, a biologist at the University of Texas Health Sciences Center, in San Antonio, who is not involved in the project.

To try to determine how the hormone impacts diseases of aging, Longo plans to compare rates of cancer, heart disease, and diabetes, as well as longevity data, in those with one or two copies of the gene and their unaffected relatives. Those who carry one functioning copy of the growth-hormone receptor appear normal; if they are protected against cancer and do not suffer from obesity and heart disease, they may represent a happy medium of growth-hormone exposure. So far, the scientist has genotyped about 300 people--100 with two copies of the mutation, and 200 relatives and controls.

"If blocking growth hormone is associated with an improvement or decreased incidence of cancer, there are tools that we have as physicians to address that," says Pinchas Cohen, a pediatric endocrinologist at the University of California, Los Angeles, who has treated children with Laron dwarfism. Drugs that inhibit secretion of the hormone or block its action already exist. And drug companies are now testing blockers of a molecule that acts downstream of growth hormone, called IGF-1, as a treatment for cancer. If IGF-1 works, it's not yet clear if the most effective intervention will be as a preventative measure, perhaps targeting families with a history of cancer, or if growth-hormone or IGF-1 depletion could be used as a cancer treatment.

Not everyone is optimistic that limiting growth hormone in people will have the same effects it does in mice. "Growth hormone in humans is different than that of most mammals," says Austad. It has a broader mechanism of action and appears to have evolved rapidly since we diverged from other mammalian ancestors. "No one knows why," says Austad, "but something has happened to make growth hormone very different in humans."

DNA-Based Artificial Nose

Single-stranded DNA can be used to identify explosives and other airborne compounds.

Smart sniffer: Cogniscent's electronic nose (above) now uses sensors made from short sequences of single-stranded DNA that can detect toxic and explosive chemicals in the air.
Credit: Cogniscent

Scientists have found a way to quickly identify which DNA sequences are ideal for detecting a particular odor and turn dried DNA into odor detectors. While many researchers are working on an electronic nose to detect toxins and explosives, this new platform could be used to create a wide array of sensors using existing high-throughput molecular-biology equipment.

"Now what we can do is take a microarray of 20,000 sensors ... and pick out those sensors that best respond to the odors of interest," says lead researcher Joel White of Cogniscent, a company based in North Grafton, MA, that manufactures odor-detection devices.

Compared with man-made sensor technologies developed for vision and hearing, our ability to mimic the chemical senses--smell and taste--is relatively primitive. To detect explosive materials such as TNT, scientists typically design highly specific polymers that fluoresce when they come in contact with their target compounds. But building a more generalized electronic nose platform that could detect a wider range of chemicals hasn't been possible.

Over the past decade, White and neuroscientist John Kauer of Tufts University have been working to improve their patented electronic nose, a handheld device that contains an array of 16 sensor types made of synthetic polymers. These polymers are cross-reactive, so that several sensor types may change shape in response to a single odor--a design analogous to the human nose. The polymers are dyed with a fluorescent marker, and their activation patterns can be monitored via optical electronic sensors and analyzed by an embedded microprocessor. But after 10 years of hard work, the pair had only been able to incorporate about 50 synthetic polymers--far less than the estimated 1,000 sensors in a human nose, which can respond to some 10,000 different odors.

Several years ago, the duo decided to test DNA--a natural polymer that is ubiquitous in the biological laboratories where the scientists spend most of their time. "When we first started talking about it with people, nobody imagined that dye-labeled DNA dried onto a substrate would respond to odors," says White.

The scientists began their experiments haphazardly: by scavenging short pieces of single- and double-stranded DNA from neighboring labs at Tufts and looking at their responses to several standard compounds. Their first experiments with dye-labeled double-stranded DNA gave them a hint that the approach could work, but all the sequences they tried responded to odors in the same way.

Single-stranded DNA, on the other hand, provided repeatable responses to odors, and this response depended on the specific sequence of four amino-acid types that make up the genetic code. With a typical sequence about 20 amino acids long, the team has the potential to create millions of sensor types. In the current issue of PLoS Biology, the researchers describe the response of just 30 sequences, but White says that now they have identified hundreds of useful DNA sequences, including one that responds to the vapor signature of TNT-containing land mines--an unusual finding indicating the versatility of the technique.

Alan Gelperin at Philadelphia's Monell Chemical Senses Center hails the discovery as a major step. "The whole field has been hindered by a lack of diverse sensor technology," he says. "This is the first demonstration that [DNA] could be used in this way." Since first learning of the approach during a conference, Gelperin has collaborated with University of Pennsylvania physicist Charlie Johnson to take the concept one step further by incorporating an electronic readout made with carbon nanotube transistors.

For now, White says that his team has incorporated his DNA sensors alongside the synthetic polymers in targeted projects, including one device for detecting ammonia gas, which would be useful for warning emergency responders at toxic spills or for monitoring pollution from livestock operations. He says that there is even interest among vintners in developing a device that could help sniff out counterfeit wines. "This was news to me," White says, laughing.