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Giving graphene the bends makes it transistor-ready
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IN BRIEF Wonder graphene gets the bends
Weaver ants see off little bees with help of flower power MOST flowers don’t want pesky ants hanging around scaring away would-be pollinators. Not so the Singapore rhododendron – the first flower found to recruit ants to chase poor pollinators away. Francisco Gonzálvez at EEZA, the arid zone experimental station in Almeria, Spain, and colleagues studied flowers frequented by large carpenter bees (Xylocopa) and a much smaller solitary bee, Nomia. The larger bees seemed to be better pollinators – setting far more fruit than the smaller bees. The team found that Nomia avoided plants with
weaver ant patrols, and when they did dare to land, were chased away or ambushed by the ants. Being so much bigger, carpenter bees weren’t troubled by the ants (Journal of Ecology, DOI: 10.1111/1365-2745.12006). Plants usually produce chemical repellents to scare off insects that prey on their pollinators. But lab tests suggested Gonzálvez’s flowers were actively attracting weaver ants, although how remains a mystery. The team thinks carpenter bees choose flowers with ants so they don’t have to compete with Nomia. Michael Kaspari of the University of Oklahoma in Norman says this is a new kind of plant-ant interaction, and that the team makes a “strong case” for the rhododendron manipulating the behaviour of weaver ants to ward off inefficient pollinators.
Blood, sweat and no tears heal wounds HUMANS have evolved a sweaty way to repair skin wounds. It was thought that the body repairs wounds such as bed sores and burns by generating new skin cells from hair follicles or the skin at the edges of the wound – the same way that other animals do. But Laure Rittié from the University of Michigan Medical School and colleagues have shown that a type of sweat gland not 16 | NewScientist | 1 December 2012
found in animals also plays a role. The team used a laser to create minor wounds in 31 volunteers. Over the following week they took skin biopsies of the wound to identify where new skin cells had grown. Before wounding, there were few new cells in the eccrine glands, which help regulate temperature, but four days later there were plenty. This suggests that the glands contain a reservoir
of adult stem cells that can be recruited to repair wounds (The American Journal of Pathology, doi.org/jtp). Humans have three times more eccrine glands than hair follicles, making them the major contributor to new skin cells. The finding is “unexpected and against current dogma”, says Elaine Fuchs from the Howard Hughes Medical Institute in Maryland. Rittié says the work has “taken the first step to identifying new therapies in wound healing”.
BENDING something might break it, or give it new life: graphene grown with bends in it has a quality it needs to act as a transistor. Graphene’s one-atom-thick sheets of carbon allow electrons to zip through fast, which could be a boon to ultra-fast computers. The problem is that graphene is not a semiconductor and so cannot switch current on and off, which is necessary for transistors. Now Ed Conrad at the Georgia Institute of Technology in Atlanta and colleagues have found a simple way to give graphene this switching ability. The trick was to grow graphene sheets on a rippling surface covered in parallel trenches. Where the surface of the sheet dipped, the graphene’s properties became semiconducting. And these strips were just 1.5 nanometres wide, allowing any transistors built on them to be ultra-tiny (Nature Physics, doi.org/jtg).
Flab-linked gene fights the blues A GENE that predisposes you to piling on the pounds may also help ward off depression. Obesity and depression are known to be linked – each makes you more likely to experience the other. David Meyre of McMaster University in Hamilton, Ontario, Canada, and colleagues thought that a mutation in a gene called FTO that makes us more prone to obesity might also increase the risk of depression. But when the researchers pooled studies across 28,000 people, they found that the FTO variant actually cuts the risk by 8 per cent. Given its prevalence, the variant probably prevents 5.3 per cent of cases of depression that would otherwise affect white Europeans (Molecular Psychiatry, doi.org/jtn).
IN BRIEF Wonder graphene gets the bends
Weaver ants see off little bees with help of flower power MOST flowers don’t want pesky ants hanging around scaring away would-be pollinators. Not so the Singapore rhododendron – the first flower found to recruit ants to chase poor pollinators away. Francisco Gonzálvez at EEZA, the arid zone experimental station in Almeria, Spain, and colleagues studied flowers frequented by large carpenter bees (Xylocopa) and a much smaller solitary bee, Nomia. The larger bees seemed to be better pollinators – setting far more fruit than the smaller bees. The team found that Nomia avoided plants with
weaver ant patrols, and when they did dare to land, were chased away or ambushed by the ants. Being so much bigger, carpenter bees weren’t troubled by the ants (Journal of Ecology, DOI: 10.1111/1365-2745.12006). Plants usually produce chemical repellents to scare off insects that prey on their pollinators. But lab tests suggested Gonzálvez’s flowers were actively attracting weaver ants, although how remains a mystery. The team thinks carpenter bees choose flowers with ants so they don’t have to compete with Nomia. Michael Kaspari of the University of Oklahoma in Norman says this is a new kind of plant-ant interaction, and that the team makes a “strong case” for the rhododendron manipulating the behaviour of weaver ants to ward off inefficient pollinators.
Blood, sweat and no tears heal wounds HUMANS have evolved a sweaty way to repair skin wounds. It was thought that the body repairs wounds such as bed sores and burns by generating new skin cells from hair follicles or the skin at the edges of the wound – the same way that other animals do. But Laure Rittié from the University of Michigan Medical School and colleagues have shown that a type of sweat gland not 16 | NewScientist | 1 December 2012
found in animals also plays a role. The team used a laser to create minor wounds in 31 volunteers. Over the following week they took skin biopsies of the wound to identify where new skin cells had grown. Before wounding, there were few new cells in the eccrine glands, which help regulate temperature, but four days later there were plenty. This suggests that the glands contain a reservoir
of adult stem cells that can be recruited to repair wounds (The American Journal of Pathology, doi.org/jtp). Humans have three times more eccrine glands than hair follicles, making them the major contributor to new skin cells. The finding is “unexpected and against current dogma”, says Elaine Fuchs from the Howard Hughes Medical Institute in Maryland. Rittié says the work has “taken the first step to identifying new therapies in wound healing”.
BENDING something might break it, or give it new life: graphene grown with bends in it has a quality it needs to act as a transistor. Graphene’s one-atom-thick sheets of carbon allow electrons to zip through fast, which could be a boon to ultra-fast computers. The problem is that graphene is not a semiconductor and so cannot switch current on and off, which is necessary for transistors. Now Ed Conrad at the Georgia Institute of Technology in Atlanta and colleagues have found a simple way to give graphene this switching ability. The trick was to grow graphene sheets on a rippling surface covered in parallel trenches. Where the surface of the sheet dipped, the graphene’s properties became semiconducting. And these strips were just 1.5 nanometres wide, allowing any transistors built on them to be ultra-tiny (Nature Physics, doi.org/jtg).
Flab-linked gene fights the blues A GENE that predisposes you to piling on the pounds may also help ward off depression. Obesity and depression are known to be linked – each makes you more likely to experience the other. David Meyre of McMaster University in Hamilton, Ontario, Canada, and colleagues thought that a mutation in a gene called FTO that makes us more prone to obesity might also increase the risk of depression. But when the researchers pooled studies across 28,000 people, they found that the FTO variant actually cuts the risk by 8 per cent. Given its prevalence, the variant probably prevents 5.3 per cent of cases of depression that would otherwise affect white Europeans (Molecular Psychiatry, doi.org/jtn).