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Damage developing in a material can be difficult to see until something breaks or fails. A new polymer damage indication system automatically highlights areas that are cracked, scratched or stressed, allowing engineers to address problem areas before they become more problematic. The early warning system would be particularly useful in applications like petroleum pipelines, air and space transport, and automobiles - applications where one part's failure could have costly ramifications that are difficult to repair. Led by U. of I. materials science and engineering professor Nancy Sottos and aerospace engineering professor Scott White, the researchers published their work in the journal Advanced Materials. "Polymers are susceptible to damage in the form of small cracks that are often difficult to detect. Even at small scales, crack damage can significantly compromise the integrity and functionality of polymer materials," Sottos said. "We developed a very simple but elegant material to autonomously indicate mechanical damage." The researchers embedded tiny microcapsules of a pH-sensitive dye in an epoxy resin. If the polymer forms cracks or suffers a scratch, stress or fracture, the capsules break open. The dye reacts with the epoxy, causing a dramatic color change from light yellow to a bright red - no additional chemicals or activators required. The deeper the scratch or crack, the more microcapsules are broken, and the more intense the color. This helps to assess the extent of the damage. Even so, tiny microscopic cracks of only 10 micrometers are enough to cause a color change, letting the user know that the material has lost some of its structural integrity. ""Detecting damage before significant corrosion or other problems can occur provides increased safety and reliability for coated structures and composites," White said. White and Sottos are affiliated with the Beckman Institute for Advanced Science and Technology at the U. of I. The researchers demonstrated that the damage indication system worked well for a variety of polymer materials that can be applied to coat different substrates including metals, polymers and glasses. They also found that the system has long-term stability - no microcapsule leaking to produce false positives, and no color fading. In addition to averting unforeseen and costly failure, another economic advantage of the microcapsule system is the low cost, Sottos said. "A polymer needs only to be 5 percent microcapsules to exhibit excellent damage indication ability," Sottos said. "It is cost effective to acquire this self-reporting ability." Now, the researchers are exploring further applications for the indicator system, such as applying it to fiber-reinforced composites, as well as integrating it with the group's previous work in self-healing systems. "We envision this self-reporting ability can be seamlessly combined with other functions such as self-healing and corrosion protection to both report and repair damage," Sottos said. "Work is in progress to combine the ability to detect new damage with self-healing functionality and a secondary indication that reveals that crack healing has occurred."


News Article
Site: http://www.rdmag.com/rss-feeds/all/rss.xml/all

Damage developing in a material can be difficult to see until something breaks or fails. A new polymer damage indication system automatically highlights areas that are cracked, scratched or stressed, allowing engineers to address problem areas before they become more problematic. The early warning system would be particularly useful in applications like petroleum pipelines, air and space transport, and automobiles - applications where one part's failure could have costly ramifications that are difficult to repair. Led by U. of I. materials science and engineering professor Nancy Sottos and aerospace engineering professor Scott White, the researchers published their work in the journal Advanced Materials. "Polymers are susceptible to damage in the form of small cracks that are often difficult to detect. Even at small scales, crack damage can significantly compromise the integrity and functionality of polymer materials," Sottos said. "We developed a very simple but elegant material to autonomously indicate mechanical damage." The researchers embedded tiny microcapsules of a pH-sensitive dye in an epoxy resin. If the polymer forms cracks or suffers a scratch, stress or fracture, the capsules break open. The dye reacts with the epoxy, causing a dramatic color change from light yellow to a bright red - no additional chemicals or activators required. The deeper the scratch or crack, the more microcapsules are broken, and the more intense the color. This helps to assess the extent of the damage. Even so, tiny microscopic cracks of only 10 micrometers are enough to cause a color change, letting the user know that the material has lost some of its structural integrity. ""Detecting damage before significant corrosion or other problems can occur provides increased safety and reliability for coated structures and composites," White said. White and Sottos are affiliated with the Beckman Institute for Advanced Science and Technology at the U. of I. The researchers demonstrated that the damage indication system worked well for a variety of polymer materials that can be applied to coat different substrates including metals, polymers and glasses. They also found that the system has long-term stability - no microcapsule leaking to produce false positives, and no color fading. In addition to averting unforeseen and costly failure, another economic advantage of the microcapsule system is the low cost, Sottos said. "A polymer needs only to be 5 percent microcapsules to exhibit excellent damage indication ability," Sottos said. "It is cost effective to acquire this self-reporting ability." Now, the researchers are exploring further applications for the indicator system, such as applying it to fiber-reinforced composites, as well as integrating it with the group's previous work in self-healing systems. "We envision this self-reporting ability can be seamlessly combined with other functions such as self-healing and corrosion protection to both report and repair damage," Sottos said. "Work is in progress to combine the ability to detect new damage with self-healing functionality and a secondary indication that reveals that crack healing has occurred."


The early warning system would be particularly useful in applications like petroleum pipelines, air and space transport, and automobiles - applications where one part's failure could have costly ramifications that are difficult to repair. Led by U. of I. materials science and engineering professor Nancy Sottos and aerospace engineering professor Scott White, the researchers published their work in the journal Advanced Materials. "Polymers are susceptible to damage in the form of small cracks that are often difficult to detect. Even at small scales, crack damage can significantly compromise the integrity and functionality of polymer materials," Sottos said. "We developed a very simple but elegant material to autonomously indicate mechanical damage." The researchers embedded tiny microcapsules of a pH-sensitive dye in an epoxy resin. If the polymer forms cracks or suffers a scratch, stress or fracture, the capsules break open. The dye reacts with the epoxy, causing a dramatic color change from light yellow to a bright red - no additional chemicals or activators required. The deeper the scratch or crack, the more microcapsules are broken, and the more intense the color. This helps to assess the extent of the damage. Even so, tiny microscopic cracks of only 10 micrometers are enough to cause a color change, letting the user know that the material has lost some of its structural integrity. ""Detecting damage before significant corrosion or other problems can occur provides increased safety and reliability for coated structures and composites," White said. White and Sottos are affiliated with the Beckman Institute for Advanced Science and Technology at the U. of I. The researchers demonstrated that the damage indication system worked well for a variety of polymer materials that can be applied to coat different substrates including metals, polymers and glasses. They also found that the system has long-term stability - no microcapsule leaking to produce false positives, and no color fading. In addition to averting unforeseen and costly failure, another economic advantage of the microcapsule system is the low cost, Sottos said. "A polymer needs only to be 5 percent microcapsules to exhibit excellent damage indication ability," Sottos said. "It is cost effective to acquire this self-reporting ability." Now, the researchers are exploring further applications for the indicator system, such as applying it to fiber-reinforced composites, as well as integrating it with the group's previous work in self-healing systems. "We envision this self-reporting ability can be seamlessly combined with other functions such as self-healing and corrosion protection to both report and repair damage," Sottos said. "Work is in progress to combine the ability to detect new damage with self-healing functionality and a secondary indication that reveals that crack healing has occurred." Explore further: New recipe for self-healing plastic includes dash of food additive


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Site: http://www.biosciencetechnology.com/rss-feeds/all/rss.xml/all

The human brain needs a large amount of energy to function properly, and researchers at the University of Illinois have reported in a new study that the health of brain metabolism in young adults may predict fluid intelligence – the capacity to solve unusual logic-based problems in novel situations. Study author Ryan Larsen, a research scientist at the Beckman Institute for Advanced Science and Technology, told Bioscience Technology that using magnetic resonance spectroscopy measurements are one of several ways to better understand the complicated relationships between energy production and intelligence. The findings were published online in Cerebral Cortex. For the study, the team, led by Larsen, University of Illinois Ph.D. candidate Aki Nikolaidis, and Beckman Institute director Arthur Kramer, analyzed data from 71 young adults.  The researchers measured the amount of N—acetyl aspartate (NAA), a biochemical marker of neural energy production and efficiency, in the brains using MR spectroscopy.   The subjects in the study were given computerized standard tests of fluid intelligence that required problem solving, reasoning and spatial visualization, Larsen said. The scientists then looked at the relationship between NAA concentrations in different areas of the brain and the results of the fluid intelligence scores. According to Larsen, the connection between NAA concentration and multiple facets of intelligence has been shown previously, but most of those studies did not use spectroscopic imaging and therefore were limited in the spatial coverage of the brain. “Our approach used spectroscopic imaging techniques to cover several areas of the brain known to be important for intelligence,” Larsen said. The current study also wanted to address other inconsistencies in previous research that may not have accounted for all relevant factors, such as brain size, in their analysis of cognition.  This study was able to image the brain’s capacity to produce energy and showed concentrations of NAA in the brain in a more detailed way than previous studies. The team found that distribution of NAA in the frontal and parietal lobes, an area of the brain associated with motor abilities, was specifically linked to fluid intelligence, independent of brain size. Interestingly, it was not linked to other closely related cognitive abilities. Brain metabolism and health, along with brain size, are significant predictors of fluid intelligence, the researchers concluded. According to the researchers, the findings suggest “that the left motor regions play a key role in visualization and planning” that is needed for spatial cognition and reasoning. So while overall, brain size is not changeable, Larsen said he is interested in understanding the potential relationships between NAA levels and health interventions, such as aerobic fitness and nutrition, which are things that can be improved and changed. Larsen said that while literature indicates that NAA is relatively stable over much of the adult lifespan, making it a useful marker of brain health, more research needs to be conducted as to whether or not changes in NAA may occur with lifestyle changes. Establish your company as a technology leader! For more than 50 years, the R&D 100 Awards have showcased new products of technological significance. You can join this exclusive community! Learn more.


News Article
Site: http://www.cemag.us/rss-feeds/all/rss.xml/all

Blood serum proteins have been observed combining one-to-one with gold nanoparticles and prompting them to aggregate, scientists at Rice University report. This is unexpected, according to Rice researchers Stephan Link and Christy Landes, who have led studies of the proteins most responsible for keeping solids in blood separated. In low concentrations, they say, the proteins irreversibly attach, unfold, and then bring nanoparticles together. This is counter to the purpose of albumin proteins, the most abundant in the blood stream, they say. The paper, published this month in the American Chemical Society journal ACS Nano, has implications for diseases caused by aggregation, like Alzheimer’s, and for nanoparticle toxicity issues, the researchers say. Gold nanoparticles are increasingly being used as therapeutic agents. Several years ago the Rice team found that higher concentrations of bovine serum albumin (BSA), a near-match for its human counterpart, could keep naturally hydrophobic gold nanoparticles from clumping. In new experiments, some using technology that has only become available in recent years, BSA proteins in low concentrations were observed to unfold in the presence of gold nanoparticles. “We think the protein is attaching first and unfolding, and that prevents other proteins from coming in,” Link says. “But it also facilitates the aggregation.” “This is the most common protein in blood serum,” Landes says. “Its job is to surround and make a nice hard shell around anything in solution that would otherwise be insoluble and stabilize the complicated mixture of cells, proteins and hormones in blood. “What’s important is the protein’s ability to successfully coat otherwise hydrophobic steroid hormones, nanoparticles, viruses, anything,” she says. “But in order for it to make that coating, it needs to stay nicely folded.” By unfolding in the presence of gold nanoparticles, they say, the protein does two things: It spreads out on the particle, leaving no room for other proteins to attach, and exposes its usually hidden hydrophobic core, which encourages aggregation with other protein-nanoparticle sets. “This is an issue whether people use nanoparticles for therapeutic purposes or just come into contact with nanoparticles in products or the environment,” Landes says. “If serum albumin can do its job, everything’s fine. But we can’t help but notice that protein unfolding, protein aggregation and fibril formation are at the root of all sorts of diseases.” While their previous research showed albumin proteins in high concentrations keep nanoparticles soluble, “there are biological situations where the concentration of serum albumin protein could be low enough to cause problems,” Landes says. They also note that two other blood-borne proteins, fibrinogen and globulin, cause gold nanoparticles to aggregate regardless of their concentrations. “They unfold no matter what the concentration, meaning that the BSA or human serum albumin are really designed to make this coating and keep everything from running out of control,” Link says. “We’re saying people really need to pay attention to the ratio between the protein — in this case, BSA — and nanoparticles, because different things can happen.” Co-lead authors of the paper are Rice alumni Sergio Dominguez-Medina, now a postdoctoral researcher at the French Atomic Energy and Alternatives Energy Commission in Grenoble, France; and Lydia Kisley, now a postdoctoral research associate at the Beckman Institute and the School of Chemical Sciences at the University of Illinois, Urbana-Champaign. Co-authors are Rice graduate students Lawrence Tauzin, Anneli Hoggard, Bo Shuang, Sishan Chen, Lin-Yung Wang and Paul Derry; postdoctoral researchers Swarnapali Indrasekara and Anton Liopo; and Eugene Zubarev, an associate professor of chemistry and of materials science and nanoengineering. Link and Landes are both associate professors of chemistry and of electrical and computer engineering. The National Science Foundation, the Welch Foundation, and the National Institutes of Health funded the research.

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