Tag Archive: Chemistry


28 January, 2013 

MessageToEagle.com – The fiber that spiders spin — weight for weight — are at least five times as strong as piano wire.

Now, scientists are able to unravel the mystery.

They have found a way to obtain a wide variety of elastic properties of the silk of several intact spiders’ webs using a sophisticated but non-invasive laser light scattering technique.

“Spider silk has a unique combination of mechanical strength and elasticity that make it one of the toughest materials we know,” said Professor Jeffery Yarger of ASU’s Department of Chemistry and Biochemistry, and lead researcher of the study.


Click on image to enlargeFemale Nephila clavipes on her web. The web was characterized using Brillouin spectroscopy to directly and non-invasively determine the mechanical properties. (Credit: Jeffery Yarger)
“This work represents the most complete understanding we have of the underlying mechanical properties of spider silks.”

Spider silk is an exceptional biological polymer, related to collagen (the stuff of skin and bones) but much more complex in its structure. The ASU team of chemists is studying its molecular structure in an effort to produce materials ranging from bulletproof vests to artificial tendons.

The extensive array of elastic and mechanical properties of spider silks in situ, obtained by the ASU team, is the first of its kind and will greatly facilitate future modeling efforts aimed at understanding the interplay of the mechanical properties and the molecular structure of silk used to produce spider webs.

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Lab-on-a-chip detects trace levels of toxic vapors in homes near Utah Air 

Force Base
by Staff Writers
Ann Arbor MI

Terra Daily

 


Core microanalytical components of the recently field-tested U-M analyzer. Image courtesy: Edward T. Zellers.

A lab-on-a-chip technology that measures trace amounts of air contaminants in homes was successfully field-tested by researchers at the University of Michigan. Even in the presence of 50 other indoor air contaminants, the U-M-built microsystem found levels of the targeted contaminant so low that it would be analogous to finding a particular silver dollar in a roll stretching from Detroit to Salt Lake City.

“This is the first (known) study of its kind,” said Ted Zellers, professor in the U-M School of Public Health and the Department of Chemistry, and project director.

“Most lab-on-a-chip technologies are used for biomedical analysis of liquids,” Zellers said. “Our technology is designed for monitoring contaminants in the air, and this groundbreaking study is the first to prove that it can work outside the laboratory in real-life applications.”

The applications are potentially limitless because the device, called a microfabricated gas chromatograph, can be tailored to detect any contaminants, Zellers said. For instance, the team is adapting the same technology to detect certain industrial chemicals in the breath and saliva of exposed workers, biomarkers of cancer and other chronic disease, and markers of explosives for airport screening applications.

The Department of Defense contracted the U-M team to adapt and test two prototypes devices in homes near Utah’s Hill Air Force Base to measure indoor concentrations of trichloroethylene, or TCE. TCE was used on military bases until the 1970s, and improper disposal caused TCE to become a pervasive groundwater contaminant that can seep into homes above plumes.

“The core microfabricated silicon chips, when stacked, are roughly the size of a wristwatch,” Zellers said. They require less power and can be made smaller and less expensively than traditionally manufactured counterparts.

The microsystem was designed and built by faculty and students affiliated with the Center for Wireless Integrated MicroSensing and Systems in the College of Engineering.

Zellers said the group is currently negotiating with several companies interested in commercializing the technology.

A series of articles describing the results appeared this month in the journal Environmental Science and Technology. Co-authors include Sun Kyu Kim, Hungwei Chang, and Jonathan Bryant-Genevier, of U-M; David Burris of IST, Inc., and Kyle Gorder and Erik Dettenmeier of Hill Air Force Base.

 

Related Links
University of Michigan
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