JON CARTWRIGHT – Page 40 – & THREE QUARKS EDITORIAL

Axions could solve lithium problem

Physics WorldJon Cartwright15 February, 2012

Published in Physics World, 15 Feb 2012

For more than a decade, scientists have been aware that the theory used to explain how the lightest elements are created overestimates the overall amount of lithium-7 in the universe. Now, physicists in the US think the answer to this so-called lithium problem might lie in a hypothetical particle known as the axion – although many are not convinced.

The theory is called Big Bang nucleosynthesis and describes a stage early in the universe’s evolution when, at temperatures of thousands of degrees, protons and neutrons began to assemble into atomic nuclei and form the first light elements: deuterium, along with isotopes of helium and lithium. As temperatures dropped, nucleosynthesis drew to a close, and eventually electrons began to add themselves to the nuclei during a period called recombination. At this time, photons stopped scattering off charged particles and the universe became transparent. […]

The rest of this article is available here.

Nanoparticles slow iron absorption in the gut

Chemistry WorldJon Cartwright12 February, 2012

Published in Chemistry World, 12 Feb 2012

Nanoparticles used in food and pharmaceuticals could have unintended physiological effects. This is the suggestion of US researchers who have showed that polystyrene nanoparticles can affect the uptake of iron – an essential nutrient – in a model intestine.

Manmade fine particles, including nanoparticles, are now regularly used in food and pharmaceuticals – so regularly that a person in a developed country consumes as much as 100 trillion of them every day; mostly titanium dioxide, silicates and aluminosilicates found in food additives. As a result, scientists have been eager to investigate possible adverse health effects. A high reactivity thanks to their huge surface area, and an ability to pass through cell membranes, are just two areas of concern. […]

The rest of this article is available here.

Listening with a ‘quantum ear’

Physics WorldJon Cartwright9 February, 2012

Published in Physics World, 9 Feb 2012

Physicists are very good at making measurements with single photons of light. Soon, however, they may also be doing routine studies of single phonons – single quanta of sound. That is the claim of physicists in Sweden and Germany, who say they have detected acoustic waves that are so weak they are – almost – at the quantum limit.

Recent years have seen a great effort to work with mechanical oscillations in the quantum regime. In such a regime, a mechanical device would be able to both emit and detect single phonons – just as optoelectronic devices are already able to emit and detect single photons. In 2010 a group at the University of California, Santa Barbara, US, demonstrated that it could create single phonons using a cryogenically cooled mechanical oscillator, thereby taking the first step on the quantum road. […]

The rest of this article is available here.

Shortages spur race for helium-3 alternatives

Chemistry WorldJon Cartwright12 January, 2012

Published in Chemistry World, 12 Jan 2012

The Japan Proton Accelerator Research Complex (J-PARC), based in Tokai, was supposed to be one of the leading facilities of its kind, allowing an unprecedented view of microstructures in the life and physical sciences. But when the $1.5 billion (£1 billion) facility opened in 2009, it was missing something important: helium-3, a neutron-detector material. Thanks to a global shortage, which came to light the year before, availability of helium-3 has plummeted while prices have skyrocketed.

J-PARC needs 100,000 litres of helium-3 to run properly, but has secured only 85,000 litres.

Faced with such a massive shortfall, J-PARC, together with more than a dozen other neutron-scattering facilities all over the world, is now investigating alternatives to helium-3 neutron detectors. And they’re not the only ones. Government agencies are also in on the search, because border security devices have traditionally used helium-3 to detect the transport of illicit, neutron-emitting radioactive material. But with helium-3 reserves eroding rapidly, the question is whether these alternatives will arrive soon enough and whether they can help all helium-3 users. […]

The rest of this article is available here.

IBM’s new memory races ahead

Physics WorldJon Cartwright1 January, 2012

Published in Physics World, 1 Jan 2012

Scientists at the computing firm IBM have demonstrated a prototype of their next generation “racetrack” memory that can be made to work with standard silicon technology, as used in conventional computer chips. The development of IBM’s novel memory could provide a major step towards “universal” devices that combine the advantages of both hard disk drives and solid-state memory such as flash drives that are used in USB sticks. […]

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Why biophysics works for me

Physics WorldJon Cartwright1 January, 2012

Published in Physics World, 1 Jan 2012

Five scientists talk to Jon Cartwright about why they are drawn to problems on the border between biology and physics.

People go into biophysics for a variety of motivations, but if one reason stands out, it is this: it focuses on phenomena that are familiar to all of us. While some topics in physics can seem esoteric and far removed from everyday life, biophysics can be more personal. How does a cell work, for example, or what is the molecular basis of AIDS? These are questions to which everyone can relate.

Yet perhaps biophysics is also attractive to scientists because it is fairly new, and draws from many other disciplines. You might have trained as a nuclear physicist, a computer programmer or a physical chemist and still have much to offer. Here, five scientists with interests in biophysics – all with very different backgrounds – reveal what they enjoy about their subject. […]

The rest of this article is available here.

A Shirt That Cleans Itself

ScienceJon Cartwright15 December, 2011

Published in ScienceNOW, 15 Dec 2011

Tired of washing your clothes? In the future, the chore might be as easy as hanging them in the sun, according to researchers who have developed a type of self-cleaning cotton. The idea is not totally new: Coatings such as titanium dioxide have long been known to have self-cleaning properties. When light strikes, the compound emits oppositely charged particles known as electron-hole pairs, which encourage so-called oxidation reactions, breaking down organic material such as dirt. […]

The rest of this article is available here.

Mechanical Amplifier Nears Quantum Noise Limit

ScienceJon Cartwright14 December, 2011

Published in ScienceNOW, 14 Dec 2011

Amplifying electrical signals while minimizing noise is crucial to a lot of modern technology. Now, scientists have created a device that amplifies microwaves with almost the minimum amount of noise allowed by quantum mechanics. The device could be used to process the sensitive outputs of quantum computers, which are expected to outperform conventional computers in years to come.

Noise is ever-present in electrical signals. Some of it arises simply because atoms have heat—they jostle around, knocking into one another. But even when there is no heat—that is, when temperatures have dropped close to absolute zero—noise remains. That’s because of a fundamental tenet of quantum mechanics, which says that space is always filled with fluctuating energy, or quantum jitters. […]

The rest of this article is available here.

Scientists unveil tiniest switch

Chemistry WorldJon Cartwright13 December, 2011

Published in Chemistry World, 13 Dec 2011

Researchers in Germany claim to have created the world’s smallest molecular switch, relying on the movement of just a single proton. The switch could help scientists to develop molecular electronics for ultra-small computing devices.

Molecules have long been proposed as alternative circuit components. In 1974, IBM researchers described how a single molecule could pass current in just one direction, thereby acting as a diode, and since then various other components, such as transistors and switches, have been put forward. In theory, single molecule electronics should be smaller than their silicon counterparts, and may require less power. […]

The rest of this article is available here.

‘Burgeroids’ Cause Double Rainbows

ScienceJon Cartwright12 December, 2011

Published in ScienceNOW, 12 Dec 2011

Red and yellow and pink and green—for scientists, a rainbow isn’t much of a mystery. Sunlight bounces off raindrops, splitting into its constituent colors and heading backwards at a precise angle, which makes a rainbow appear as a semicircle wherever you stand. But what about two rainbows at once? Now, researchers performing computer simulations think they have an explanation for this odd phenomenon. […]

The rest of this article is available here.