Our Changing World for Thursday 30 April 2009
On This Programme
An electron microscope image of carbon nanotubes. For comparison, the width of a human hair is 50 to 100 micro metres.
Nanotechnology - Carbon Wires
In the first part in our series about nanotechnology, Julie McPherson (pictured below, on the left), a chemist at the University of Warwick, discusses the use of carbon nanotubes as electrical wires.
The discovery that carbon can form stable, ordered structures other than graphite and diamond sparked an interest in these molecules as potential materials for electronic and other nano-scale devices.
In 1985, Nobel laureate Harry Kroto discovered that stars were producing spherical molecules that were made up of 60 carbon atoms. He called them Buckminster Fullerenes, after the American architect Richard Buckminster Fuller, whose geodesic domes they resemble. C-60 soon became known as a Buckyball, and was followed by Bucky tubes and Bucky onions - all made up entirely of carbon.
The discovery of carbon nanotubes, molecular-scale tubes of graphitic carbon, stimulated interest worldwide when it was discovered that they were among the stiffest and strongest fibres known and could conduct electricity and therefore be used as nano-scale wires.
Julie McPherson visited New Zealand to attend the AMN-4 conference on nanotechnology, organised by the MacDiarmid Institute for Advanced Materials and Nanotechnology, and to talk about her plans to use carbon nanotubes in miniature sensors that measure tiny concentrations of neuro-transmitters in the brain.
Introduced Mammals in the Subantarctic
New Zealand's subantarctic islands are a World Heritage site but they are far from pristine. While some mammals, such as goats, pigs and rabbits were introduced deliberately to provide food for ship-wrecked sailors, other animals such as rats and mice arrived accidentally on early sailing ships.
Campbell Island was farmed in the early 1900s, and the feral cattle and sheep were removed in stages between the 1970s and the 1990s. In 2001 Peter McClelland from the Department of Conservation led the world's largest rodent eradication which removed Norway rats from the island.
Adams Island in the Auckland Islands group is free of introduced mammals, and rabbits, mice and cattle have been eradicated from Enderby Island. While goats have been removed, Auckland Island still has mice, pigs and cats, for which the Department of Conservation is planning a major eradication. In January 1999 a Rare Breeds Society expedition removed seventeen pigs which have been bred on the mainland. Auckland Island pigs are virus-free, and considered to have a value in xenotransplants.
Alison Ballance amidst flowering megaherbs that have flourished on Campbell Island following the removal of feral sheep (image: Sarah Cowhey).
There are nearly 200 species of native ferns in New Zealand, and a growing number of introduced ferns. Fern expert Patrick Brownsey(on right, in front a king fern) co-authored "New Zealand Ferns and Allied Plants", and he is an internationally respected biosystematist and herbarium curator who manages the herbarium WELT at Te Papa Tongarewa, the Museum of New Zealand. He was awarded the 2008 Allan Mere by the New Zealand Botanical Society for an outstanding contribution to New Zealand botany. Te Papa botanist Leon Perrie (on left) has been investigating the molecular history of New Zealand ferns.
Rare Genetic Diseases
University of Otago geneticist Stephen Robertson's primary research interest lies in the underlying causes of congenital malformations, especially in relation to a family of rare genetic conditions affecting the formation of the skeleton, face and limbs. While he was investigating a particular gene on the X-chromosome which causes a rare bone-formation disorder, he made the surprising discovery that this genetic mutation was linked to a childhood kidney cancer called Wilms Tumour.
Previously, Stephen Robertson discovered a family of genes called filamins and the role they play in a suite of genetic disorders. This work began with a study of one such condition which affected a large North Island family. It was the subject of a television documentary called Lifting of the Makutu.
Louise Chilvers studies New Zealand sealions in the subantarctic; Leon Perrie and Patrick Brownsey are back with more fern stories; and in our next nanotechnology interview, chemist Annie Powell talks about mimicking nature in nano-scale devices.