The Top 4 Public Health Stories of 2006
TB Makes a Scary Comeback
An outbreak in South Africa of an extremely drug-resistant strain of the tuberculosis bacterium is raising international alarm. While the incidence of highly drug-resistant tuberculosis in the United States is still negligible, the disease is gaining ground in countries where large numbers of people have immune systems weakened by HIV. In healthy individuals, the TB bacterium can hide in white blood cells and remain dormant for years, but among those with a suppressed immune system, the bacillus can take off. In 2006 the virulent strain killed a cluster of 120 rural HIV-infected South Africans.
Epidemiologists worry that the combination of HIV-burdened immune systems and total drug resistance could put TB on the fast track to causing an uncontrollable epidemic. Mario Raviglione, director of the World Health Organization's TB effort, says that containing the new strain will require a massive influx of cash—on the order of $56 billion. "We currently have six classes of anti-TB drugs, and if we can't use them effectively, we're back to the pre-antibiotic age," he says. "Then there's nothing we can do except remove a lung—and pray."
Jocelyn Selim
Milk Drinkers More Likely To Have Twins
Women who consume milk and other dairy products have twins more than twice as often as do vegan moms, according to Long Island Jewish Medical Center obstetrician Gary Steinman. The finding may help explain the strange 60 percent surge in the rate of twin births in the United States between 1977 and 2002.
The study, published in May in the Journal of Reproductive Medicine, compared the frequency of twins in the general population with that in the obstetrical histories of 1,042 vegan mothers. Steinman suspects that the disparity may be due to a protein in milk called insulin-like growth factor (IGF), which is associated with multiple ovulation. Vegans have lower blood concentrations of IGF than women who consume dairy regularly. Although IGF is present in other animal products, including meat, it seems to survive digestion only when in milk.
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Of course, reproductive technologies like in vitro fertilization increase the twinning rate, as does the trend of delaying childbirth, but Steinman argues that dietary factors also play a role. In 1993 the FDA approved the use of recombinant bovine growth hormone in cows for the purpose of increasing milk production; milk from hormone-treated animals is especially rich in IGF. Between 1992 and 2001, the twinning rate in the United States increased twice as much as it did in the United Kingdom, where the hormone is banned. "We're doing something different," Steinman says, "and the only difference I can find is this growth hormone."
Jennifer Barone
Cesareans Boost Death Risk for Baby
A study of nearly 6 million low-risk births has found that the neonatal mortality rate for delivery by cesarean section is nearly three times the rate for vaginal delivery: 1.77 deaths per 1,000 live births via cesarean, as opposed to 0.62 deaths per 1,000 for vaginal delivery. By limiting their survey to full-term pregnancies with no complications, Marian MacDorman, of the Centers for Disease Control and Prevention, and colleagues eliminated the influence of medically necessary cesareans. While it's not clear why vaginal birth is safer for infants, previous studies suggest that hormones released during labor may help prepare babies to breathe outside the womb. In 2004, C-sections accounted for nearly 30 percent of American births.
Jennifer Barone
Polio's Return Traced to Lapses in India
In May a 39-year-old man in Namibia tested positive for poliovirus, marking the country's first case in 10 years. Since then, the outbreak there has reached 20 confirmed cases. This year 10 other formerly polio-free countries are once again battling the disease. Genetic sequencing has traced cases in five of the countries, including Namibia, to a polio strain in India, where the virus remains endemic. As of October 2006, a total of 358 cases have occurred in the poor, densely populated north Indian state of Uttar Pradesh alone, up from 29 in 2005. The World Health Organization has taken India to task, saying its outbreak is endangering efforts worldwide to keep the disease at bay. To protect a high-risk community from polio, at least 95 percent of the children must be vaccinated; but in late 2005 and early 2006 the vaccination rates in Uttar Pradesh dipped to between 85 and 90 percent. The Indian government, vowing to eliminate polio by 2007, has discussed a pilot project using an injectable vaccine in addition to oral drops. The injectable vaccine is thought to offer better protection against polio infection in children with diarrhea, which is common in the area.
The Top 3 Science Policy Stories of 2006
The cervical cancer vaccine—the second vaccine after the hepatitis B vaccine to target a sexually transmitted disease—debuted this year. In June the Food and Drug Administration approved the vaccine, distributed under the brand name Gardasil, for girls and women ages 9 to 26. The European Union and Australia have also approved the vaccine, and a similar product to be manufactured by GlaxoSmithKline is in the works.
The vaccines work by inducing antibodies to the human papillomavirus, or HPV, which can cause genital warts and cervical cancer. In large clinical trials, the vaccines were more than 99 percent effective in preventing HPV infection. Like most vaccines, however, they are most effective among people who have not yet been exposed to the virus. An American government advisory panel therefore recommended that Gardasil be given routinely to 11- and 12-year-old girls—and in some cases to girls as young as 9.
Every year cervical cancer kills more than 230,000 women worldwide, about 80 percent of them in developing countries. In the United States, the disease claims the lives of roughly 4,000 women each year. Based on a mathematical model, GlaxoSmithKline claims that immunizing every 12-year-old girl with the vaccine would reduce U.S. cases and deaths from cervical cancer by 70 percent. But some conservative groups have opposed the vaccine, saying it might promote sexual activity.
Poor countries also face a more practical obstacle. The full course of the vaccine—three shots over a six-month period—costs about $360. "The biggest issue will be price," says John Schiller, a senior investigator at the National Cancer Institute, who did some of the early work that led to the vaccine's development. "It's the most expensive vaccine we have."
Apoorva Mandavilli
DDT is Back
More than 30 years after the use of DDT was abandoned in many countries, the much-maligned pesticide is making a comeback. In September the World Health Organization openly endorsed indoor spraying of DDT, saying it is not only the best weapon against malaria, it is also cheaper and more effective than other insecticides. The announcement followed a similar move in May by the United States Agency for International Development (USAID).
One of the reasons for the more aggressive stance is President Bush's Malaria Initiative, launched in 2005 after Congress reproved USAID for spending the lion's share of its budget on operational costs—and less than 8 percent on the insecticides, bed nets, and medicines that would actually save lives. In 2007, USAID plans to spend more than $20 million on indoor spraying—up from less than $1 million spent in 2005.
Many environmental groups support the use of DDT for malaria—but only in the short term. Meanwhile, USAID representatives say that, when used properly, the chemical poses little risk to the environment or to human health. "Until we find that it is hazardous," says Admiral Tim Ziemer, coordinator of the President's Malaria Initiative, "it's unconscionable not to use something that can save lives."
Apoorva Mandavilli
Nano Risks Worry Scientists
"Magic Nano" turned out not to be so magical after all. The cleaning product sold by the German company Kleinmann GmbH made headlines when it caused respiratory distress in more than 100 consumers last spring, leading to its swift removal from the market. Although the product didn't contain nanoparticles—the problems were ultimately traced to the formation of a super-thin film—the incident put the concept of nanomaterials (which incorporate particles or components measuring less than 100 nanometers, or about 1/250,000 inch) squarely in the public eye and raised the question of how to harness their potential while addressing their potential risks.
More than 200 consumer products around the world are described as nanotech-based, according to the Woodrow Wilson Center's Project for Emerging Nanotechnologies. On small scales, substances often behave much differently than they do in their familiar forms, and toxicology and safety studies of these products are still in the early stages. "Good science takes time," says Sally Tinkle, assistant to the deputy director of the National Institute of Environmental Health Sciences at the NIH. "We're asking the right questions about our regulatory frameworks, but we do not have enough scientific data yet to know if they need to be changed and, if so, how to change them in a way that would be more effective." Time may be running out, says David Rejeski, director of the Project on Emerging Nanotechnologies. "Five or six years ago, this was a story about science. Now it's a story about consumer products," he says. "This is the beginning of a tidal wave of nano-based products."
So far, more effort has been put into promoting the economic potential of nanomaterials than in exploring possible hazards. The Bush administration's 2007 budget request includes $1.2 billion for the National Nanotechnology Initiative but just $44 million for nanotechnology toxicology and safety research. "How many Magic Nano stories have to appear before people get upset and start to lose confidence?" Rejeski says. "The thing that I fear is that we're investing in a $200,000 car, and we've taken out a $10,000 insurance policy."
Sarah Webb
The Top 6 Physics Stories of 2006
Quantum Teleportation Leaps Toward Reality
Scientists have teleported information between light and atoms...
Invisibility Cloak Invented!
The "first practical realization" of a cloak of invisibility...
New Letters Explore Einstein's Private Life
A cache of letters reveal a complicated picture of the man...
Anti-Repulsion Discovered
This year physicists forced atoms to be bound by their mutual repulsion...
Light Moves in Reverse
Physicists at the University of Rochester have coaxed light into traveling backward...
Element 118 Debuts On the Periodic Table
Chemists will soon have to make room on the periodic table for a new element discovered in October...
The Top 7 Technology Stories of 2006
Neuroscientist John Donoghue of Brown University has brought us a big step closer to the day when people can interact with computers directly through the power of thought. In July he and his team published a paper in Nature outlining remarkable progress in picking up brain signals with implanted electrodes and using those signals to control a range of devices.
The experiments were conducted on a 25-year-old Massachusetts man paralyzed from the neck down. In 2004, surgeons placed a tiny 100-electrode array in his primary motor cortex, the brain region that controls voluntary movement, to collect electrical impulses from nerve cells and send them to a series of signal processors. Donoghue and his colleagues then supervised as the computer translated the man's thoughts of moving his arm and hand into the actual movement of external devices. On the first day the system was up and running, he was able to master the technique. He could move a computer cursor, play a video game, open e-mails, draw a crude circle, operate a television remote control, and even move a prosthetic hand and arm—using nothing other than his will.
The same basic brain-computer interface system had been tested earlier in monkeys, and a group in Georgia implanted electrodes in people as far back as the 1990s. But no other group has used implanted electrodes to monitor so many human neurons at once or had such impressive results.
The system was removed from the original subject after 14 months. It is now being tested on three other patients, including one with ALS. Neurologist Leigh Hochberg, the lead author on the paper with Donoghue, hopes that the current trials are the first step toward giving severely disabled people an unprecedented degree of independence. "The participants in these trials are pioneers," he says.
Nicholas Bakalar
  The BrainGate implant's array of 100 hair-thin electrodes (left) delves the cortex and eavesdrops on neurons that normally control hand and arm movement. On an MRI image of the brain (right), the square shows the tiny area the device covers. |
Who Failed New Orleans?
Over the last 50 years, the Army Corps of Engineers built some 350 miles of levees to protect New Orleans from hurricanes, a complex defense system that failed spectacularly when Katrina struck. To figure out what went wrong, the Corps appointed a task force of 150 scientists and engineers. On June 1 the Interagency Performance Evaluation Task Force issued its 6,000-page nine-volume answer, describing engineering lapses, design failures, and decades of neglect that led to antiquated structures neither high nor strong enough to withstand a storm like Katrina.
In fact, the levees had been designed to withstand only a category 3 storm. Katrina's winds were a strong category 3 when it hit land, but because the storm had reached category 5 at sea, it brought with it the storm surge of a much stronger hurricane. Although studies done in the 1970s indicated the need for increased flood protection, the Corps had never redesigned the system. The report also took the Corps to task for failing to keep track of the effects of subsidence: In New Orleans, the ground sinks over time. Levees and floodwalls had sunk by as much as 2½ feet in some places since the system was built. Because of budget cuts, the Corps may have rejected fixes and skimped on materials. Instead of building all levees with clay, for instance, engineers settled too often for sandy, silty hydraulic fill that was merely capped with clay. When Katrina hit, these structures gave way to the surge and waves.
At a press conference in New Orleans, Lt. Gen. Carl Strock, chief of engineers and commander of the Corps during Katrina, took responsibility for the failure of the levees, which the report called "a system in name only." Robert Bea, an engineer at the University of California at Berkeley and coauthor of an independent study, applauds the Corps for facing up to its failures but says the task force did not go far enough. Focusing on the engineering failure does not address organizational problems that led to a broader culture of neglect. "The Corps knew the system was outdated and wrong, and yet nobody talked about it," says Bea.
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Ed Link, a civil and environmental engineer who directed the task force for the Corps, believes the tragedy cannot be blamed on one agency alone. "I think we, as a nation, are just too risky," he says. "We didn't make a long-term investment in New Orleans, and we got caught. We got caught big time."
Megan Mansell Williams
Chemistry Turns Straw Into Black Gold
In April researchers at Rutgers University and the University of North Carolina announced a remarkably versatile technique for converting wastes, coal, or almost any source of carbon into synthetic diesel and gas. Devised by chemist Alan Goldman of Rutgers University and his team, the new method builds on Fischer-Tropsch chemistry, which was invented for making synthetic fuel in Germany more than 80 years ago. Called alkane metathesis, the technique combines two catalytic reactions to cut up relatively low-value hydrocarbon chains and recombine them into chains of useful lengths. For example, it can transform two 6-carbon chains into a 2-carbon chain (a good heating gas) and a 10-carbon chain (perfect as a diesel fuel). Improving the method's yield and efficiency could allow the United States to convert some of its abundant coal supplies into synthetic fuels, reducing the nation's dependence on imported oil.
Samir S. Patel
In August researchers announced the creation of a microscopic device that can make an electrical connection to an individual neuron, an invention that might one day lead to synthetic substitutes for damaged nerve cells.
, a chemist at Harvard University, and his colleagues devised a tool that can record, stimulate, and modulate signals at multiple points on a neuron, from individual dendrites to axons, essentially duplicating the way that brain cells communicate. The device is so small—just 20 nanometers across—that 50 can fit on a neuron. While other researchers have made electrical connections to the nervous systems of animals and humans, until now no one has been able to forge a link at the level of individual axons or dendrites. "These devices can be used not only to record signals but to apply voltages back to the nerve cell," Lieber says. "We could stimulate a neuron to fire and control the rate of propagation of the electrical impulse."
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Charles Lieber
The invention has profound implications for research and treatment. Using multiple inputs, it could soon be possible to decipher how neurons pass signals back and forth and how learning, memory, and other processes occur. Implanted in the brain, Lieber's electrodes might one day serve as prostheses to help damaged nerves regain their function. "The goal," he says, "is the betterment of the human condition."
 Silicon-laser hybrid chips could make computers 100 times faster. |
Laser-Emitting Chips Promise Ultrafast Computers
Nothing is faster than light. So for decades engineers have tried to accelerate the pace of conventional, electricity-based computer chips by melding them with laser-based signal processors (like those used to send Internet data blazing through fiber-optic cables). In September researchers from Intel Corp. and the University of California at Santa Barbara announced they had found a promising way to achieve that long-sought goal.
The corporate and university teams set out to develop a hybrid design that could handle both electricity and light. They bonded a thin layer of indium phosphide, a compound that acts as a medium for the laser, onto silicon sheets by exposing both materials to a blast of hot, electrically charged oxygen atoms; the indium phosphide was spiked with aluminum gallium indium arsenide to give it added speed. A microlayer of oxides then formed on the two surfaces, gluing them together. "We can make thousands of lasers with just one bond, as opposed to bonding each laser individually," says John Bowers of UC Santa Barbara, coinventor of the new device.
When energized by electrical current, the bonded layer produces light that travels through channels in the silicon to a "modulator" that flickers the light tens of billions of times per second. A couple dozen lasers switching at this speed could handle a trillion bits of information per second—more than 100 times as fast as current silicon chips. What wonders will such power bring? For one thing, Bowers and his team say, by the end of the decade their new chips could make it possible to download a feature-length movie in just a few seconds.
Curt Suplee
Capacitors Could Replace Batteries
"Who killed the electric car?" a documentary film asked this year. One major culprit is basic chemistry; batteries are lousy at storing and releasing an electric charge. But the electric car may get a second lease on life because of recent advances in an alternative technology—a type of electricity sponge called an ultracapacitor.
Unlike batteries, which work through relatively slow chemical reactions, ultracapacitors store electricity on the surface of an electrode; thus they can be recharged almost instantly. The downside is that ultracapacitors hold only a fraction as much energy as a comparable-size battery. In February researchers led by MIT engineer Joel Schindall unveiled an ultracapacitor whose plates are covered with a dense carpet of straw-shaped carbon molecules, or carbon nanotubes. The nanotubes drastically increase the surface area of the ultracapacitor electrode, allowing it to hold 20 times as much energy. Devices based on this breakthrough could reach consumers in less than five years, Schindall estimates.
Eric Smalley
Machines Learn How to Feel
Engineers at the University of Nebraska reported in June that they had developed a way to give robots a sense of touch: electronic skin that is cheap, flexible, and twice as sensitive as a human fingertip. This sensitivity comes from a film made of alternating monolayers of gold and cadmium sulfide nanoparticles separated from each other by a very thin polymer film. Any pressure against the electronic skin increases conductivity through the film.
Artificial skin could help robots grab fine objects, like Mars rocks. Another use, says researcher Ravi Saraf, is a probe that could sense cancerous tissue inside a patient. To test the skin's medical applications, Saraf says, "we just went to the butcher shop and started buying livers and muscles." If the concept works, biopsies may one day be replaced by a tiny mechanical caress.