NSF turns to ancient pottery to improve modern heat resistant ceramics

In order for space vehicles to work properly, they have to be able to withstand the cold of space, which can be as low as 250 degrees Fahrenheit below zero. Then, some vehicles have to be able to withstand the extreme heat of reentry, which can be as hot as 3000 degrees. Hot enough to melt most any metal. As most know, the Space Shuttle was fitted with ceramic tiles on its underbelly to keep the vehicle from overheating as it came back to Earth, which was made all the more apparent when damage to the tiles resulted in the loss of Columbia in 2003. But ceramics are used in other components as well, and will be needed as more ambitious projects are undertaken in the future. Equally important is the ability of ceramics to remain chemically unchanged when subjected to such temperature variations. Such properties allow for the construction of components that minimize expansion and contraction under such stresses, which can be critical for long term operations in space. This is why the NSF has turned to research scientists to see if the ancient Greeks can provide some insight.

Such research will involve using something called x-ray absorption near edge structure (XANES) - which is a special type of spectroscopy, along with other types of x-ray techniques, to find out what has gone on with iron oxidation in the pottery under study. What’s needed is a better understanding of the molecular structure of iron minerals that were used to make the pottery to help researchers in designing newer and better types of ceramics for future space missions, whether manned or otherwise.

What’s interesting is that it is apparently the degree to which the iron in the ancient ceramic pottery oxidized that caused the distinctive red and black colorations that made it so attractive to those that worked with it all those years ago.

 

Antibiotics wrapped in nanofibers turn resistant disease-producing bacteria into ghosts

 Encapsulating antibiotics inside nanofibers, like a mummy inside a sarcophagus, gives them the amazing ability to destroy drug-resistant bacteria so completely that scientists described the remains as mere "ghosts," according to a report today at the the 241st National Meeting & Exposition of the American Chemical Society (ACS).

Mohamed H. El-Newehy, Ph.D., leader of the nanofibers research team, said the new technology has potentially important applications in the on-going battle against antibiotic-resistant infections. Estimates suggest that more than 100,000 people in the United States alone develop such infections each year, with nearly 20,000 deaths. Health care costs from those infections may exceed $20 billion annually.

"The rapid emergence of bacteria resistant to commonly used antibiotics has become a serious public health problem," said El-Newehy. "There is an urgent need to identify new antibiotics that work in different ways that can overcome resistance. Our approach is not a new antibiotic, but a new way of delivering existing antibiotics."

That approach, El-Newehy explained, could make new treatments available to patients much faster than trying to discover and develop brand-new medicines, a process that typically takes 10-12 years and costs $800 million to almost $2 billion. It could be used against a broad range of bacteria to fight disease, prevent bacterial and fungal contamination in the food industry, inhibit the growth of microorganisms in drinking water and enhance the effects of chemotherapy, he added.

It involves putting common antibiotics inside nanofibers made of polyvinyl alcohol and polyethylene oxide — wisps of plastic-like material so small that peach hair or a strand of spider silk are gigantic by comparison. Nanofibers can't even be seen under a regular microscope, and almost a billion could be lined up side-by-side along the length of a yard stick.

El-Newehy's group knew that nanofibers have special properties due to their high surface area to weight ratio. Those properties have kindled research on multiple biomedical applications nanofibers, including wound dressings, medical textiles, antibacterial materials to control post-operative inflammation, and new ways of delivering drugs. They decided to test the effects of nanofibers with multiple antibiotics encapsulated directly into fiber, using laboratory cultures of various microbes. Antibiotics wrapped inside nanofibers were highly effective in killing a variety of disease causing bacteria and fungi, including Escherichia coli and Pseudomonas aeruginosa, two increasingly drug-resistant microbes.

"When treated with antibiotics wrapped in nanofibers, the microbes were severely damaged and many cells were enlarged, elongated, fragmented, or left as just empty ghosts," El-Newehy said. "The fibers by themselves, without antibiotic did not affect the bacteria. They seem to work by boosting the power of the antibiotics. By wrapping the anti-microbial agents in the fibers, it makes the drug action more focused and the agents are effective for longer period of time than with conventional delivery techniques."

El-Newehy, with the Petrochemical Research Chair, Department of Chemistry College of Science, King Saud University, Riyadh, Riyadh, Saudi Arabia, said that besides drug delivery, nanofibers are being used for tissue engineering, wound dressing, medical textiles and antimicrobial materials that can be used to control post-operative inflammation, promote wound healing and dressing, especially for diabetic ulcers.

Salem Al-Deyab, Ph.D., the supervisor of Petrochemical Research Chair at King Saud University, said that this study was funded by the Petrochemical Research Chair at King Saud University, Saudi Arabia. In addition, Petrochemical Research Chair has the lead in the possession of the first machine (Nanospider) for producing nanofibers in Saudi Arabia, said Al-Deyab. Officials plan a major effort to develop the Nanofibers Research Center at Petrochemical Research Chair to become a major center for Nanofibers Research for different applications at King Saud University, said Al-Deyab.

Provided by American Chemical Society (news : web)