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Our World — 12 April 2008

MUSIC: "Our World" theme

Straight ahead on "Our World" ... Antibiotics from alligator blood ... the sense of smell and our survival instinct ... and a new kind of computer memory with a funny name ...

PARKIN: "So we need to think of radically different circuit architectures, computer architectures, and in particular, shift towards the third dimension. That's what racetrack technology – perhaps – will enable."

The race to develop racetrack memory, Cousteau in the Amazon, and more. I'm Art Chimes. Welcome to VOA's science and technology magazine, "Our World."

Alligators are big, fearsome reptiles that look like they're straight out of a dinosaur horror movie. They're not the kind of creatures you'd think about if you were looking for a new medicine. But researchers in Louisiana have found that alligators and their unusual immune system may one day help us in our fight against serious infections. Véronique LaCapra reports.

LaCAPRA: Growing up hunting and fishing in the swamps of Louisiana and Southeast Texas, Mark Merchant was around a lot of alligators. Now an Associate Professor of Biochemistry at Louisiana's McNeese State University, he still has a strong admiration-and respect-for these fiercely territorial predators.

MERCHANT: "Alligators are very aggressive animals, and they in engage in a lot of fighting within members of their own species. And during these fights they sometimes can inflict serious injury on each other, including loss of entire limbs."

LaCAPRA: Alligators spend their lives in wetlands, in what amounts to a marshy soup of bacteria, so you might think that wounded animals would be prime targets for infection. But speaking on a mobile phone from Argentina, where he is doing research, Merchant said that's not the case.

MERCHANT: "Despite the fact that they live in an environment which is very conducive to infection, they heal most often without any signs of infection and quite rapidly in fact."

LaCAPRA: The surprising healing abilities of alligators prompted Merchant to look more closely at their immune system.

MERCHANT: "One of the things that we're very excited about is that we think that we have some very strong evidence that their white blood cells are producing small proteins that have some pretty incredible antibiotic and antifungal activities."

LaCAPRA: Lancia Darville, a graduate student at Louisiana State University and a collaborator on Merchant's research, describes one of his early experiments:

DARVILLE: "He was able to take alligator blood and expose it to various strains of bacteria – 23 different strains of bacteria to be specific – and he found that all 23 were depleted. And in comparing that to human blood, doing the exact same experiment, he only found that eight of the bacteria were depleted, not all 23, which was a good indication that the alligators had different proteins present that we as humans don't have, that causes their bodies to respond the way that they do."

LaCAPRA: Darville has been working on the next step in this research:

DARVILLE: "The overall goal of this research is to be able to separate and identify the antimicrobial proteins that are present in the American alligator that are causing them to have such a high innate immune system."

LaCAPRA: By isolating these proteins and determining their chemical structure, Merchant and Darville hope they can ultimately be used to develop new antibiotics for human use.

For example, the proteins could be used in antibiotic creams for treating foot ulcers in diabetics, or preventing infections in burn patients. If all goes well, alligator-based medications could be available for human use in seven to ten years.

Darville says the alligator proteins also show promise for combating viruses.

DARVILLE: "And long term, Dr. Merchant is suggesting that these blood proteins may also be used to fight off the HIV virus, which is the virus that causes AIDS.

LaCAPRA: Darville presented their research on April 6 at the national meeting of the American Chemical Society. I'm Veronique LaCapra.

Scientists say treating genital herpes, a viral infection that is rampant throughout sub-Saharan Africa, does not prevent the spread of the virus that causes AIDS. But researchers remain convinced that genital herpes, a sexually transmitted disease, makes people more vulnerable to HIV. VOA's Jessica Berman reports.

BERMAN: Experts say between 50 and 80 percent of people who live in sub-Saharan Africa are infected with the sexually transmitted virus herpes simplex 2, known as genital herpes, by the time they reach the age 35. In the same region, 90 percent of the people who are HIV positive are infected with genital herpes.

Herpes simplex is not deadly, but like HIV, is not curable. It can only be suppressed with anti-viral drugs.

Researchers point to studies that show herpes-simplex infection increases the risk of acquiring HIV by three-fold. The researchers tried to show treating individuals with genital herpes would make them less vulnerable to infection with the deadly AIDS virus.

Stephen Lagakos is a professor of biostatistics at Harvard University in Cambridge, Massachusetts.

LAGAKOS: "The motivation was sound. I think the quality of the study from what I could tell from reading the paper was very good. The investigators are very good investigators, and they failed to show a benefit."

BERMAN: The study, reported this week in the New England Journal of Medicine, involved a group of 800 women in Tanzania between the ages of 16 and 35 infected with herpes simplex.

Debby Jones-Watson is a senior clinical investigator at the London School of Hygiene and Tropical Medicine and the study's lead author. Jones-Watson is not ready to give up on the research.

JONES-WATSON: "The actual antiviral used, acyclovir, is very good for managing routine herpes cases in clinics, but may not be, perhaps be at this dosage potent enough to switch off the HSV [herpes simplex virus] mechanisms in the body that might increase susceptibility to HIV infection."

BERMAN: Investigators are now looking at other ways to suppress genital herpes for longer periods of time that they hope will provide protection against HIV.

Experts say a number of other studies are underway to see whether using acyclovir to treat genital herpes in HIV-infected individuals prevents the spread of the AIDS virus to their uninfected partners. Jessica Berman, VOA News, Washington

There's something special about our sense of smell. One sniff can transport you back to mom's kitchen, or to an exotic city you once visited. Now scientists are trying to learn more about how smell works, and how they might harness it for medical use. Health reporter Rose Hoban explains.

Our sense of smell is powerfully connected to memory. And new research shows it's also connected to how we protect ourselves.

Wen Li is a neuroscientist from Northwestern University in Chicago. She says smell is probably the oldest sense in humans and animals.

LI: "We developed this system through this long process of evolution, and also the region that supports olfactory processing is really a very ancient region in the brain. And it has a deep association with emotion, memory and other functions of the human and animal behavior."

HOBAN: Li says as we grow, we learn to associate certain scents with threat or reward. And she wanted to test how sensitive the sense of smell actually is at telling dangerous smells apart. Li took two scents that were almost identical and had subjects smell them. When the people smelled one scent, they received a small electrical shock to the wrist. They didn't get a shock when exposed to the other scent.

LI: "So after five repetitions of such odor and shock pairings, we then assessed their ability at the behavioral level, like just asked them to pick out... so we presented two bottles that contained odors, the one that was paired with shock and the counterpart."

HOBAN: Even though the two odors were nearly indistinguishable, after the experiment, subjects were consistently able to pick out the odor associated with the negative experience of being shocked.

Li and her colleagues also placed subjects into a brain scanner as they did this experiment. That way they were able to see that different parts of the brain became active when exposed to the control odor and to the odor that was associated with being shocked. And the subjects were able to differentiate between the two odors quite quickly.

LI: "The reason for that formation is to facilitate survival. So if we know the signal is predicting a threat, or a reward, then it's very helpful for us when we encounter the signal we can get ourselves ready for a fight or flight."

HOBAN: Li works in a center for studying Alzheimer's Disease. She says one of the early signs of impending memory loss is losing this ability to discriminate between smells.

Li's work is published in the journal Science. I'm Rose Hoban.

Time again for our Website of the Week, when we showcase interesting and innovative online destinations.

With billions of pages of information online, Web users often use search engines like Google to find what they're looking for. But sometimes a general purpose search engine isn't what you need.

If you're a scientist, for example, you'll want to use a search engine specifically designed for your needs, such as our Website of the Week,

CAWLEY: "Scirus is a science-specific search engine. So it allows researchers to search for scientific information only. We don't just use web crawling, but we also index important university and research institute databases. Some say it's the deep scientific web, and that's really where Scirus can take you."

Stephen Cawley is product marketing manager for Scirus. To deliver targeted search results, Scirus searches through nearly half a billion web pages, including the content of academic journals, patents and other content that general purpose search engines simply don't have.

And if your search returns too many hits, you can refine it using tools that appear alongside the search results.

CAWLEY: "If you look at the left-hand side of the screen, you can actually see the different types of content, whether it's patents, journals, whether it's web pages, and how many of that type of content is actually returned on the search result."

More than a million users a month take advantage of Scirus's search function, and now they have a new way to use the site: topic pages with essays written by experts on a wide and expanding range of subjects. Cawley says, which is still in the "beta" stage of development, combines the expert narrative and relevant search results.

CAWLEY: "So the Scirus search index does an analysis of the title of this topic page and then actually returns related results. So, if you like, the topic page acts as a waypoint for researchers, where experts give their expert recommendations on what content should actually be explored."

Stephen Cawley stresses that although Scirus is a product of one of the leading scientific publishers, Elsevier, the search results are delivered without any bias.

Web searching for scientists at, or get the link from our site,

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Your search has ended for VOA's science and technology magazine, Our World. I'm Art Chimes in Washington.

If you have a computer or a mobile phone or any of a variety of other electronic devices, you've got some solid-state memory, or memory chips, inside. You may also have information stored on a hard drive. Each kind of data storage has advantages and disadvantages. Solid state memory is more expensive, but also a lot faster. One kind, flash memory, can only be written-to so many times before it wears out. Another, called volatile memory, will forget everything if it loses power. Hard drives are a lot cheaper, but a lot slower, and as mechanical devices they can crash, wiping out your data.

If only there were one kind of memory technology that combined the advantages of all the existing types of memory.

That's been a holy grail of researchers for years, and one promising prospect has the curious name, "racetrack memory."

PARKIN: "Racetrack is, I think, a very important paradigm shift"

Stuart Parkin has been working on racetrack memory at IBM's Almaden Research Center in Silicon Valley, and he described this new, and still theoretical, technology this week in the journal Science.

Today's computer memory devices are two-dimensional, so to increase capacity or speed, you have to increase the density. At some point, however, the laws of physics make that increasingly difficult.

PARKIN: "There are many physical laws that will and are preventing us from continuing that evolution. So we need to, essentially, think of radically different circuit architectures, computer architectures, and in particular, shift towards the third dimension. That's what racetrack technology, perhaps, will enable."

Existing memory technologies work only in two dimensions. To move into the third dimension, Parkin uses microscopic nanowires that can be magnetized. Or more accurately, parts of the nanowire can be magnetized separately, each part divided by what's known as a domain wall, which he says has useful physical properties.

PARKIN: "We can detect it and measure it, and it can be used to store information. So the concept of racetrack is a bit like, if you think of a forest of trees, we're going to build a forest of trees above the surface of a silicon wafer, and these vertical magnetic nanowires will be magnetized to create a series of these magnetic domain walls. And with some very recent new physics, we have shown that we can move a series of these magnetic domain walls up and down the nanowire (or the trunk of this tree) to essentially take the information from way up there in the branches of the tree way down into the roots, where we would have devices for reading and writing the domain walls."

If I can mix metaphors, you can think of racetrack memory like a multi-story warehouse, where bits of data are stored upstairs and brought down on an elevator when they're needed. Obviously, you can store much more stuff in a 10-story building than you can in a one-story building with the same footprint.

PARKIN: "In the same area of this silicon device, where we previously had one bit of information, we would now have this tall tree with maybe 10-100 bits of information stored in the trunk, and we only bring the information down to the surface of the silicon wafer when we want to read it or write it."

So far, racetrack memory is a laboratory concept, not an actual product.

PARKIN: "But we think that we've demonstrated the essential physics and the essential materials that make it possible – there are no fundamental roadblocks we can see now to developing very interesting, novel racetrack memory technology in the next two to four years."

If racetrack memory does make it to the market place – and, of course, there are no guarantees – IBM researcher Stuart Parkin says it could pave the way for smaller computers, with a single kind of inexpensive solid-state memory replacing conventional read-only (RAM) memory and hard-drive disk storage. That, in turn, would allow for simpler software. All in all, it would be one more step on the long path of ever-smaller but more capable computers.

U.S. television viewers this week got a chance to learn more about the Amazon region and the threats it faces, in a documentary showcasing the region's awesome beauty and the critical role it plays in the world's climate system. Lester Graham has our report.

GRAHAM: The Amazon and its tributaries make up the largest river system in the world.

DOCUMENTARY NARRATOR: "In spite of the enormous scale of this tropical rainforest basin, scientific evidence increasingly has revealed how fragile this ecosystem is. And how what happens here will influence global climate dramatically, possible irreversibly, within the next 10 to 20 years."

GRAHAM: This two-part program produced by Jean-Michel Cousteau, Return to the Amazon, shows that trees are the key to creating rain in the region and keeping the river alive.

Fifty percent of moisture for rain in the Amazon is released directly from the trees. So fewer trees means less rain.

Twenty percent of the Amazon rainforest has already been cut down. And scientists predict if 30-40 percent of the Amazon forest is cut, it will pass a tipping point, becoming too dry to survive, and no longer absorbing climate-changing carbon dioxide.

Jose Alvarez Alonso is with the Peruvian Amazon Research Institute. In the documentary he says illegal logging not only endangers the forest, and the climate, but exploits the indigenous people: paying them a small bag of sugar to illegally cut down an entire mahogany tree, and in the process destroying their way of life.

ALVAREZ ALONSO: "I can tell you that the mahogany taken out of the Amazon now is stained with blood."

GRAHAM: Most of the logging is, at least, controversial. Much of it's corrupt. And, often, illegal. But Brazil still exports massive amounts of wood. That's because people in the U.S. and Europe keep buying the rainforest wood.

In the 25 years since Jean Michel Cousteau last visited the Amazon with his father Jacques Cousteau, he says there have been some disturbing changes and he wanted people to see what's going on. We asked Jean Michel Cousteau what he hopes people get from the programs.

COUSTEAU: "Well, I really hope that it will be more than people just having had a good time, discovering a place maybe they didn't know about, or have heard about but didn't focus on some of the issues, and some of the solutions, and meet some of the local people. And that beyond all of that, they will take action. I really hope that people will be aware enough to understand the connections that they have, how much we depend upon places like the Amazon for the quality of our lives, every one of us."

GRAHAM: People who watch programs like yours, they look at these things, and then they have one question: 'Well, what can I do?' What can an individual do when looking at a big problem like this?

COUSTEAU: "Well, what you can do, there's a lot you can do. As an individual, by being aware. How can you protect what you don't understand? So, what we're offering the public is answers to perhaps some of the questions or to highlight some of the problems. That allows you, as an individual decision maker, to make some better decisions when it comes to the wood you're going to buy, the next time you look at a piece of furniture, you have the right to ask the question: 'Is that coming from the rainforest?'"

GRAHAM: The two-part TV series does outline many of the problems. But it also offers some hope as researchers, environmentalists and governments in the Amazon basin work to solve some of those problems. For the Environment Report, I'm Lester Graham.

Support for the Environment Report comes from the Joyce Foundation, the Gaylord and Dorothy Donnelley Foundation, and the Consumers Energy Foundation. Send your comments to feedback at

And finally today ... at this week's meeting of the American Chemical Society in New Orleans, thousands of scientists gathered to share the latest research on topics from alligator blood, as we heard earlier, to left-handed amino acids, presented by graduate students, professors and other researchers.

And then there was 14-year-old Anshul Samar, who invented a board game to help teach chemistry.

SAMAR: "Elementeo is all about injecting fun into chemistry today. And what we're talking about here is having elements, compounds, nuclear reactions. You have oxygen life-giver to sodium dragon, putting reality and chemistry into the fantasy the kids talk in today. We have compounds from sulphuric acid to propane and supernovas and nuclear fusion reactions. Again, this is really about injecting fun into chemistry."

In the game of Elementeo, players try to wipe out their opponents by using forces whose strengths and weaknesses mirror the chemicals they're named after.

California teenager Anshul Samar has more than a thousand pre-orders and hopes to go onto production soon. He also plans an online, interactive version –

SAMAR: "Where you can have somebody from here battle somebody, you know, in Brazil and play elements and compounds with someone across the world."

When he gets a bit older, Anshul Samar says he might consider a career in chemistry, but he says he's pretty open to anything from medicine to politics.

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That's our show for this week. If you'd like to get in touch, email us at Or use the postal address –

Our World
Voice of America
Washington, DC 20237 USA

Rob Sivak edited the show. Eva Nenicka is the technical director. And this is Art Chimes, inviting you to join us online at or on your radio next Saturday and Sunday as we check out the latest in science and technology ... in Our World.