If They Build It, the Kids Need to Test It

LAST DECEMBER, the College Park KidsTeam the International Children’s Digital Library (ICDL – www.childrenslibrary.org), a nonprofit children’s library born at Maryland, began a new project. The children, ranging from 7 to years of age, began how the ICDL's digital books function on revolutionary new (shown at left and created specifically The project is part library’s new partnership One Laptop Per Child (OLPC), nonprofit organization that provides laptops to children in developing countries. priority is to ensure that all of ICDL’s books be displayed in the optimum manner on laptops,” says the digital library’s executive director Tim Browne.

The XO is designed for children who countries with little technological infrastructure. To that end, the small and bright limegreen machine is energy efficient and inexpensive (about $130 per laptop). But will it the kid test?

The College Park Kids Team has pored the XO, exploring its interface and testing the library’s books work on the machine. According to the library’s founder, Professor Allison Druin, the children gave the XO thumbs-up—with some reservations. “They loved reading books on the laptop. Kids read while curled up on the couch or the and they could do that with the laptop. they also discovered some kinks,” she says, noting that the laptop is a bit hard to open.

The children’s feedback is given to One Laptop Per Child, which is currently working evolving versions of the XO. It will be months before the digital library and OLPC decide books to install on the laptop. In the meantime, however, the partnership offers a showcase for the library’s digital collections. “One Laptop Per Child needs content that children-centric and educationally rich,” Browne says. “And there is nobody that match ICDL in those areas.” —AK

Evolutionary Discovery

EVOLUTIONARY CHANGES can take tens of thousands of years to manifest.When a university geneticist discovered a mutation in humans that took what colleagues call “the blink of an eye” to develop, she knew she’d found something significant.

Sarah Tishkoff, associate professor in the Department of Biology, and an international team of researchers found that East Africans possess a gene that is associated with the ability to digest milk as adults. Most humans can’t properly digest lactose, the sugar found in milk, beyond age four.

The discovery is remarkable because it is evidence of how genes and culture coevolve. The mutation occurred at a time, thousands of years ago, when Africans began raising cattle, and is different from the gene present in Europeans. Some populations may have adapted to meet nutritional needs during droughts or periods of scarce food.

The findings “reveal one of the most striking genetic footprints of natural selection ever observed in humans,”Tishkoff says, adding that it would’ve been completely missed if they hadn’t studied these populations. African populations have not been as well studied at the genetic level, she says, because logistics, infrastructure and the history of colonialism have been difficult to overcome.

Interested in humankind’s African origins for more than 10 years,Tishkoff and her students found the mutation after resequencing genetic samples from a subset of 500 of the more than 6,000 samples she’s collected from almost 100 tribes.

Her long-standing interest in the region, though, goes beyond looking for lactose tolerance.Tishkoff and her team are researching other adaptive associations in genes that could determine height, taste perception, disease resistance or predisposition, strength and color vision.

“This has relevance for biomedical research,” says Tishkoff, adding that Africa provides a rich resource of information. “Even from one geographical region, African populations are genetically very divergent due to their large population sizes, complex history of migration and population divergence.” —MAB

Chitosan: Providing a Sense of Safety

Using testing probes that can manipulate micro and nanoscale devices, Reza Ghodssi (second from left) and his research team are developing optical sensing technologies that may soon lead to new security and safety innovations for airports, hospitals and other public locations.

LIANGLI LUCY YU, associate professor in the Department of Nutrition and Food Science, also uses chitosan in her innovative work with nutraceuticals— natural ingredients used as food additives to prevent disease. Yu has developed a research program in nutraceutical and nutritional chemistry that she believes will have a positive impact on human health. In recognition of this research, she received the 2006 Young Scientist Award from the American Chemical Society’s Agricultural and Food Chemistry Division. “We have examined and compared commercial chitosan samples with different characteristics for their capacity to bind fat, cholesterol and bile acids,” Yu says. “These properties are important in body weight control and reducing blood cholesterol.” Yu is also collaborating with colleagues at China Pharmaceutical University to develop chitosan-derived nanomaterials for the controlled release and targeted delivery of bioactives, including nutraceuticals and pharmaceuticals. —TV

A CHEMICAL SUBSTANCE derived from the shells of crabs and other crustaceans is a key component in a microscale sensor system being developed by researchers in the A. James Clark School of Engineering. Working with scientists from the nearby University of Maryland Biotechnology Institute, the Clark School engineers are using a biological compound known as chitosan to coat components of the sensor system. This microscale “system on a chip” will eventually be able to detect explosives, bioagents, chemicals and other dangerous materials in the air and water.

“Chitosan is interesting because it can interact with a wide variety of substances, and works well in complex, sensitive devices,” says lead investigator Reza Ghodssi, associate professor of electrical and computer engineering with a joint appointment in the Institute for Systems Research.

The sensors employ microscopic vibrating cantilevers—swinging mechanical arms that can be as small as 600 nanometers in width. (There are more than 25 million nanometers to an inch.) Smaller objects can detect smaller changes, which in turn makes for more sensitive tools, Ghodssi explains.

When the cantilevers are coated with chitosan, new optical measurement technology developed by Ghodssi can determine very minute changes in how the cantilevers vibrate. The device is so sensitive that if a single targeted bacterium fell on one of the sensor’s cantilevers, the optical technology would detect a change in the cantilever’s vibration, alerting authorities to a possible danger. To view the system, go to www.ece.umd.edu/MEMS/ —TV

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