A new study suggests that Alzheimer’s disease can be detected decades before onset, using a virtual reality test.
People aged 18 to 30 were asked to navigate through a virtual maze to test the function of certain brain cells.
According to German neuroscientists, those with a high genetic risk of Alzheimer’s could be identified by their performance.
The findings could help future research, diagnosis and treatment, researchers report in the journal Science.
The scientists, led by Lukas Kunz of the German Centre for Neurodegenerative Diseases in Bonn, say the high risk group navigated the maze differently and had reduced functioning of a type of brain cell involved in spatial navigation.
The findings could give an insight into why people with dementia can find navigating the world around them challenging, they say.
“Our results could provide a new basic framework for preclinical research on Alzheimer’s disease and may provide a neurocognitive explanation of spatial disorientation in Alzheimer’s disease,” Science report says.
Although genes play a role in dementia, their effects are complex with many unknowns.
A new report in Science journal gives details on how carbon-based material graphene can help scientists study liquids more clearly with high-power microscopes.
Graphene can form a clear “window” to see liquids at higher resolution than was previously possible using transmission electron microscopes.
Liquids had been difficult to view at the same resolution as solids because these microscopes require the liquids to be encapsulated by some material.
Traditionally, silicon nitride or silicon oxide capsules, or liquid cells, have been used. But these are generally too thick to see through clearly.
Now, Jong Min Yuk at the University of California, Berkeley, and colleagues have shown that pockets created by sheets of graphene can be used to study liquids at clear, atomic, resolution using transmission electron microscopes (TEMs).
Graphene can form a clear window to see liquids at higher resolution than was previously possible using transmission electron microscopes
The researchers used their new graphene-based liquid cell to study the formation of platinum nanocrystals in solution.
With this technique, the team of scientists was able to observe new and unexpected stages of nanocrystal growth as it happened.
They noted how the crystals selectively coalesced and modified their shape.
Graphene consists of a flat layer of carbon atoms tightly packed into a two-dimensional honeycomb arrangement.
Because it is so thin, it is also practically transparent. The unusual electronic, mechanical and chemical properties of graphene at the molecular scale promise numerous applications.
Its discoverers, Andre Geim and Konstantin Novoselov from Manchester University, were awarded the Nobel Prize for Physics in 2010.
The technique described by Jong Min Yuk and colleagues might enable scientists to study other physical, chemical, and biological phenomena that take place in liquids on the nanometre scale.
“Their approach opens new domains of research in the physics and chemistry in the fluid phase in general,” said Christian Colliex, from the Universite Paris Sud in France, who was not involved with the research.
In another paper published in this week’s Science magazine, researchers from the US and Spain report that the stress of pressing the tip of an atomic force microscope into a thin film of material can switch the direction of the film’s electric charge.
This phenomenon, called “flexoelectricity”, could be harnessed to improve memory in electronic devices.
It could achieve this by allowing digital bits of information to be written mechanically but read electrically – which would use less power.
The process has been likened to a nanoscale typewriter – mechanically “writing” changes in the direction of electric charge.
A new research suggests that some Scandinavian trees survived the last Ice Age, challenging a widely held notion that they were killed off by the huge ice sheet that covered the region.
Modern trees in Scandinavia were thought to descend from species that migrated north when the ice melted 9,000 years ago.
But research suggests some conifers survived on mountain peaks that protruded from the enormous ice sheet, on islands and in coastal areas.
The work appears in Science journal.
“Our results demonstrate that not all the Scandinavian conifer trees have the same recent ancestors, as we once believed,” said Prof. Eske Willerslev from the Centre for GeoGenetics, University of Copenhagen.
“There were groups of spruce and pine that survived the harsh climate in small ice-free pockets, or in refuges, as we call them, for tens of thousands of years, and then were able to spread once the ice retreated.
“Other spruce and pine trees have their origins in the southern and eastern ice-free areas of Europe. Therefore, one can now refer to ‘original’ and later naturally <<introduced>> Scandinavian conifer species.”
A new research suggests some conifers in Scandinavia survived during last Ice Age on mountain peaks that protruded from the enormous ice sheet, on islands and in coastal areas
The researchers came to their conclusions by studying the DNA of modern spruce – which clearly portrays two Scandinavian types – and also by analysing the composition of pine and spruce DNA in sediments from lake-core samples.
“One hypothesis is that trees were able to survive on the top of nunataks, the exposed ridges or peaks of mountains protruding from glacial cover, or in more sheltered areas close to the coast where proximity to the temperate conditions of the Atlantic Ocean favoured survival,” said Laura Parducci, from the University of Uppsala.
“These areas must have provided sites for roots to anchor and trees to grow in the challenging climate.”
Today, nunataks can be found protruding from the Greenlandic ice sheet, albeit without any trees.
A new study in Science journal shows that membranes based on the “miracle material” graphene can be used to distil alcohol.
An international team created the membrane from graphene oxide – a chemical derivative of graphene.
The research team has shown that the membrane blocks the passage of several gases and liquids, but lets water through.
This joins a long list of fascinating and unusual properties associated with graphene and its derivatives.
Graphene is a form of carbon. It is a flat layer of carbon atoms tightly packed into a two-dimensional honeycomb arrangement.
Because graphene is so thin, it is also practically transparent. As a conductor of electricity, graphene performs as well as copper; and as a conductor of heat, it outperforms all other known materials.
The unusual electronic, mechanical and chemical properties of graphene at the molecular scale promise numerous applications.
Andrei Geim and Konstantin Novoselov from the University of Manchester were awarded 2010’s Nobel Prize in physics for their discovery, outlined in a scientific paper in 2004.
Andrei Geim and others have now developed a laminate made from thin sheets of graphene oxide.
These films were hundreds of times thinner than a human hair but remained strong, flexible and easy to handle.
Graphene is a flat layer of carbon atoms tightly packed into a two-dimensional honeycomb arrangement
When a metal container was sealed with agraphene film, even the most sensitive equipment was unable to detect air or any other gas, including helium, leaking through.
But when the researchers tried the same with water, they found that it evaporated without noticing the graphene seal. Water molecules diffused through the graphene-oxide membranes with such a great speed that the evaporation rate was the same whether the container was sealed or open.
Dr. Rahul Nair from Manchester University, who led the team, commented: “Graphene oxide sheets arrange in such a way that between them there is room for exactly one layer of water molecules.”
He added: “If another atom or molecule tries the same trick, it finds that graphene capillaries either shrink in low humidity or get clogged with water molecules.”
Professor Andrei Geim added: “Helium gas is hard to stop. It slowly leaks even through a millimetre-thick window glass but our ultra-thin films completely block it. At the same time, water evaporates through them unimpeded. Materials cannot behave any stranger.”
Dr. Rahul Nair said: “Just for a laugh, we sealed a bottle of vodka with our membranes and found that the distilled solution became stronger and stronger with time. Neither of us drinks vodka but it was great fun to do the experiment.”
Despite this, the researchers do not offer any immediate ideas for applications. But Prof. Andrei Geim commented: “The properties are so unusual that it is hard to imagine that they cannot find some use in the design of filtration, separation or barrier membranes, and for selective removal of water.”
In another study in Science journal, a different team reports the development of a membrane based on diamond-like carbon. This membrane has unique pore sizes that allow for the ultra-fast passage of oil through it.
One expert said it could potentially be used for filtering toxic contaminants out of water or for purifying industrial chemicals.