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Self-healing plastic oozes fluids to mimic blood clots
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ODILON DIMIER/PLAINPICTURE/PHOTOALTO
STICKS and stones may break your bones, but childhood bullying could damage your long-term health. William Copeland at Duke University in Durham, North Carolina, and his colleagues tracked 1420 children from 9 years old right through their teens. Each child was seen up to nine times during the study and quizzed about bullying. The team then measured levels of C-reactive protein in their blood. CRP is a marker of inflammation linked to higher risk of cardiovascular disease and problems like diabetes. Although CRP levels rise during adolescence, levels were highest in children who reported being tormented by bullies. Even at the ages of 19 and 21, children who had once been bullied had CRP levels about 1.4 times higher than their peers who were neither the perpetrators nor victims (PNAS, DOI: 10.1073/ pnas.1323641111). In a cruel twist, the bullies had the lowest levels of all, suggesting they didn’t suffer the same health risks. They may even see a benefit from their behaviour, although Copeland stresses it is not a vindication of their actions. Andrea Danese at King’s College London welcomes the findings, and points out that care workers could monitor levels of CRP in children having psychotherapy to see if it is helping to soothe the stress.
Hard plastic oozes fluid to heal itself PRICK this plastic and it will bleed. This self-healing material uses a process that mimics how blood can clot to repair wounds. Previous materials inspired by biology could only heal microscopic cracks. Now Scott White at the University of Illinois at Urbana-Champaign and his colleagues have created a plastic lined with fluid-filled channels that can fix damage that is visible to the naked eye. The key is the pair of liquids in the channels, which react when mixed together. One contains
long thin molecules and the other contains three-sided molecules. When the plastic is punctured, the fluids mix and the molecules link up to create a scaffold, similar to the way blood platelets and fibrin proteins join to form a clot. After a few minutes of contact, the liquids turn into a thick gel that fills the damaged area. Over a few hours, other ingredients within the fluids cause the gel to harden. Test versions in the lab were able to repair holes up to 8 millimetres wide (Science, doi. org/spr). The team thinks using
foams in place of fluids would fill larger gaps, but they haven’t tested that idea yet. White and his team hope to create plastics that incorporate many criss-crossing channels of the fluids, to ensure that they always overlap with a damaged area. The material’s first applications may be in objects in remote locations that are difficult to repair, such as spacecraft or deep-sea drilling equipment. Selfhealing shields for the military are also a likely application – the work was funded by the US air force. GRAHAM UDEN/CORBIS
Bullying leaves lasting scars
Dying stars spew cement into space EXPLODING stars act like cosmic cement mixers, according to an analysis that looks at how to spot this building material in space. Cement is made by mixing water with calcium silicates, which are molecules made of calcium, silicon and oxygen. When very massive stars die, they explode and litter space with a variety of elements – including all the ingredients of cement. So far, no one has looked for the material in space, so we don’t know how much, if any, is actually produced. Goranka Bilalbegovic´ at the University of Zagreb in Croatia and her colleagues worked out how cement particles would show up on an absorption spectrum, which measures the frequencies of light an object absorbs to reveal its chemical composition. They found that cement would have a unique infrared signature (arxiv. org/abs/1404.7392). The European Space Agency’s Infrared Space Observatory found a similar and so far unexplained signal in dust shells around 17 supernovae. If cement is made in space, it may explain why interstellar gas contains less oxygen than expected. The missing part is tied up in cement, says Bilalbegovic´.
Ancestral farms shaped your thinking IT’S a cliché to say that East Asians think in terms of the group, while Westerners think in terms of the individual. But there is truth to it, and the explanation may lie in what our ancestors ate. Rice farming may have fostered collective thinking while wheat farms favoured individualism. To grow rice, many people must work together on irrigation canals, but a lone family can grow wheat. So Thomas Talhelm at the University of Virginia in Charlottesville wondered if staple crops affect thinking. His team tested the cognitive styles, individualism and in-group
loyalty of 1162 students in China, in either wheat or rice-growing areas. They found many differences. When students drew their relationship to others, those from wheat-growing areas drew themselves larger than others, but students from ricegrowing areas did not. And when asked to group things, people from rice-growing areas grouped them by relationship rather than by physical similarities (Science, doi.org/sp4). “Rice provides economic incentives to cooperate,” says Talhelm, so people in those cultures become more dependent on each other.
17 May 2014 | NewScientist | 17
ODILON DIMIER/PLAINPICTURE/PHOTOALTO
STICKS and stones may break your bones, but childhood bullying could damage your long-term health. William Copeland at Duke University in Durham, North Carolina, and his colleagues tracked 1420 children from 9 years old right through their teens. Each child was seen up to nine times during the study and quizzed about bullying. The team then measured levels of C-reactive protein in their blood. CRP is a marker of inflammation linked to higher risk of cardiovascular disease and problems like diabetes. Although CRP levels rise during adolescence, levels were highest in children who reported being tormented by bullies. Even at the ages of 19 and 21, children who had once been bullied had CRP levels about 1.4 times higher than their peers who were neither the perpetrators nor victims (PNAS, DOI: 10.1073/ pnas.1323641111). In a cruel twist, the bullies had the lowest levels of all, suggesting they didn’t suffer the same health risks. They may even see a benefit from their behaviour, although Copeland stresses it is not a vindication of their actions. Andrea Danese at King’s College London welcomes the findings, and points out that care workers could monitor levels of CRP in children having psychotherapy to see if it is helping to soothe the stress.
Hard plastic oozes fluid to heal itself PRICK this plastic and it will bleed. This self-healing material uses a process that mimics how blood can clot to repair wounds. Previous materials inspired by biology could only heal microscopic cracks. Now Scott White at the University of Illinois at Urbana-Champaign and his colleagues have created a plastic lined with fluid-filled channels that can fix damage that is visible to the naked eye. The key is the pair of liquids in the channels, which react when mixed together. One contains
long thin molecules and the other contains three-sided molecules. When the plastic is punctured, the fluids mix and the molecules link up to create a scaffold, similar to the way blood platelets and fibrin proteins join to form a clot. After a few minutes of contact, the liquids turn into a thick gel that fills the damaged area. Over a few hours, other ingredients within the fluids cause the gel to harden. Test versions in the lab were able to repair holes up to 8 millimetres wide (Science, doi. org/spr). The team thinks using
foams in place of fluids would fill larger gaps, but they haven’t tested that idea yet. White and his team hope to create plastics that incorporate many criss-crossing channels of the fluids, to ensure that they always overlap with a damaged area. The material’s first applications may be in objects in remote locations that are difficult to repair, such as spacecraft or deep-sea drilling equipment. Selfhealing shields for the military are also a likely application – the work was funded by the US air force. GRAHAM UDEN/CORBIS
Bullying leaves lasting scars
Dying stars spew cement into space EXPLODING stars act like cosmic cement mixers, according to an analysis that looks at how to spot this building material in space. Cement is made by mixing water with calcium silicates, which are molecules made of calcium, silicon and oxygen. When very massive stars die, they explode and litter space with a variety of elements – including all the ingredients of cement. So far, no one has looked for the material in space, so we don’t know how much, if any, is actually produced. Goranka Bilalbegovic´ at the University of Zagreb in Croatia and her colleagues worked out how cement particles would show up on an absorption spectrum, which measures the frequencies of light an object absorbs to reveal its chemical composition. They found that cement would have a unique infrared signature (arxiv. org/abs/1404.7392). The European Space Agency’s Infrared Space Observatory found a similar and so far unexplained signal in dust shells around 17 supernovae. If cement is made in space, it may explain why interstellar gas contains less oxygen than expected. The missing part is tied up in cement, says Bilalbegovic´.
Ancestral farms shaped your thinking IT’S a cliché to say that East Asians think in terms of the group, while Westerners think in terms of the individual. But there is truth to it, and the explanation may lie in what our ancestors ate. Rice farming may have fostered collective thinking while wheat farms favoured individualism. To grow rice, many people must work together on irrigation canals, but a lone family can grow wheat. So Thomas Talhelm at the University of Virginia in Charlottesville wondered if staple crops affect thinking. His team tested the cognitive styles, individualism and in-group
loyalty of 1162 students in China, in either wheat or rice-growing areas. They found many differences. When students drew their relationship to others, those from wheat-growing areas drew themselves larger than others, but students from ricegrowing areas did not. And when asked to group things, people from rice-growing areas grouped them by relationship rather than by physical similarities (Science, doi.org/sp4). “Rice provides economic incentives to cooperate,” says Talhelm, so people in those cultures become more dependent on each other.
17 May 2014 | NewScientist | 17