MIT researchers who invented a new method for waterproofing soldier gear and other items that used to be tough to protect is now exploring added uses for the technology, including anti-microbial systems that are an integral part of someone’s garb. The key to the approach is a new technique for coating things with polytetrafluoroethylene (PTFE), better known as Teflon. A standard way to put a PTFE coating on something is to immerse the item in the protective chemical, but that’s not practical for certain types of materials – among them the Kevlar vests worn by soldiers. The MIT group’s solution is called chemical vapor deposition, a thermal process that puts an almost unimaginably thin PTFE coating on objects one molecule at a time. The approach not only extends PTFE’s potential for keeping out water but also raises the possibility of adding other useful substances to a coating, says Karen Gleason, a professor of chemical engineering. She’s working with Alexander Klibanoff, a professor of chemistry, on various potential applications, many based on the fact that useful items can be chemically “tethered” to PTFE molecules. “I could imagine hooking DNA onto the PTFE in order to form a biological sensor that recognizes many different types of microbes,” notes Gleason.
TRICKS OF MEMORY
You see someone who’s clearly familiar but simply can’t come up with the person’s name or remember the circumstances of prior encounters. Why do our minds sometimes have these lapses? According to MIT and Harvard researchers, it may be because different types of memories are formed using different brain regions. The group had test subjects peruse lists of words, and either connect each word to an imagined scene – “dirty,” for example, might call up images of garbage – or read the word backwards to provide a comparison. The next day, the subjects were asked if they’d seen a particular word in the near past, and if so whether they remembered the circumstances. As they pondered the issue, their brains were scanned with a sophisticated imaging technology. For those who did remember a context, e.g., they might say, “I was thinking about a garbage heap,” an area buried deep in the brain that’s known as the hippocampus was highly active. Signs of activity in a neighboring brain region, meanwhile, would usually tell you if subjects remembered the word even if they couldn’t connect it with any specific images or contexts. The findings indicate that the hippocampus – long known as a key player in memory – is heavily involved in forming the associations often crucial to effective memory. Anthony Wagner, the assistant professor of brain and cognitive sciences who led the research, says the work could boost efforts to improve older peoples’ memories. “Older adults typically have more problems with ‘source memory’ than with remembering a particular item, like a face,” he notes.
Dolly the sheep made international headlines as the first animal of its kind cloned from the cell of an adult of the same species. But despite the stir, and later debate over the issue generally, cloning animals the way Dolly was cloned is a tough proposition: only 1 percent to 3 percent of various species survive to birth if their original DNA comes from an adult animal. Why the high failure rate? A team from the MIT-affiliated Whitehead Institute for Biomedical Research and the University of Hawaii has found at least part of the answer. The researchers compared mice embryos cloned from adult cells with those whose origins trace to embryonic stem cells – that is, the types of cells formed in the earliest moments of gestation. The researchers found that of a group of 10 similar types of genes typically turned on in normal gestation, several remained dormant in the embryos created from adult cells. The work doesn’t mean the mystery has been completely put to rest. “There are hundreds of genes that are not correctly expressed in cloned animals,” notes Rudolf Jaenisch, a professor of biology at MIT, a Whitehead faculty member and the leader of the research team. The researchers, who drew on earlier studies by David Page – like Jaenisch a Whitehead faculty member and MIT professor – are now exploring other genetic obstacles to the cloning process.
BOISTEROUS BLACK HOLE
A lengthy look at the super-massive black hole located at the center of our own Milky Way galaxy shows it to be a highly active cosmic body, report astronomers from MIT and elsewhere. A black hole is an entity so dense that nothing, including light, can escape its gravitational clutches. As black holes attract material from the surrounding interstellar space, though, they can spur energetic events outside their boundaries. A NASA satellite, the Chandra X-ray Observatory, picked up frequent X-ray flares from the Milky Way’s black hole over a two-week observation period earlier this year. “We were seeing it flare on almost a daily basis,” says Frederick Baganoff, an MIT Center for Space Research scientist and a member of the international team that carried out the observations. He adds that despite the frequency of the x-ray activity, the relative weakness of the flares suggests the cosmic body may not have access to much interstellar material to “swallow” – maybe because it’s ingested most of the nearby matter already. “It’s definitely on a severe diet,” says Baganoff.