Australasian Science: Australia's authority on science since 1938


By Stephen Luntz

Chocolate, mango and blueberry benefits, forensic advances and more.

An Atom’s Shadow
For the first time the shadow of a single atom has been photographed, an event recorded in Nature Communications.

“We wanted to investigate how few atoms are required to cast a shadow, and we proved it takes just one,” said Prof Kielpinski of Griffith University’s Centre for Quantum Dynamics. An ytterbium atom was chosen because lasers with the appropriate frequency for absorption are relatively cheap.

“If we change the frequency of the light we shine on the atom by just one part in a billion, the image can no longer be seen,” Kielpinski said.

Co-author Dr Erik Streed explained that when atoms are bound to other objects the absorption frequency becomes smeared, so the atom was kept in free space by electric fields to ensure that only the exact absorption frequency would work.

The achievement required delicate work to hold the atom steady and an ultra-high resolution microscope to reveal the darkness cast on the detector where the atom blocked the light.

Chocolate Benefits Quantified
Many previous studies have touted the benefits of dark chocolate for health (AS, Nov 2010, p.12), but Monash PhD student Ella Zomer has upped the ante both in how much should be consumed and by quantifying the gains.

“We’ve predicted significant health benefits of eating 100 grams of dark chocolate every day over a 10-year period. That’s about the equivalent of one premium-quality block containing a minimum 70% cocoa,” Zomer said. “Our findings indicate dark chocolate therapy could provide an alternative to or be used to complement drug therapeutics in people at high risk of cardiovascular disease.”

Zomer estimates that consumption of 100 grams of chocolate per day could prevent 15 fatal and 70 non-fatal heart attacks or strokes if taken by 10,000 people over a 10-year period.

The research was published in the British Journal of Medicine, and even involved the suggestion that $42 per person per year should be spent on promoting the benefits of dark chocolate-related health strategies.

Aussie in Space
Australian robotics engineer Dr Andrew Howard (AS, Jan/Feb 2009, p.47) has piloted the SpaceX Dragon capsule on the last kilometre of its journey to dock with the International Space Station (ISS).

SpaceX is the first private company to successfully connect to the ISS. It is hoped that private vehicles such as Dragon will fill the gap left by the Space Shuttle in launching satellites and supplying space stations. SpaceX has plans for piloted craft once safety is established. The first mission carried half a tonne of supplies.

Howard, educated at the University of Melbourne’s Physics Department, has been based in Los Angeles for a decade, working for the NASA Jet Propulsion Laboratory, universities and now SpaceX. He was lead engineer for the Dragon Optical Navigation subsystem responsible for docking the spacecraft with the ISS.

Blueberries Reduce Muscle Damage
Consumption of blueberries helps athletes recover from strenuous exercise, according to research published in the Journal of the International Society of Sports Nutrition by A/Prof Steve Stannard of Massey University’s School of Sport and Exercise.

Stannard took an unusual approach to controlling his sample, directing ten women to work one leg so hard that it sustained muscle damage while the other was uninjured. “We put the study participants on a Biodex machine and had them do 300 maximal eccentric contractions, which causes micro-trauma to the muscle’s fibres,” Stannard said. Weeks later the same exercise was done to the other leg.

The difference was that on one occasion participants consumed blueberry smoothies before, during and for 2 days after the exercise, while on the other occasion the smoothie was blueberry-free.

Blueberries are a famously concentrated source of antioxidants. While the control smoothie had the same antioxidant content, blood samples showed higher levels of antioxidants in the blood after the blueberry smoothies, and this was associated with more rapid recovery for 36 hours after the exercise.

Mangoes Too
Mangos contain obesity-fighting compounds, but to gain the benefits people need to consume the skin rather than the flesh, a Food and Function paper has revealed.

Prof Greg Monteith of the University of Queensland’s School of Pharmacy attributed the capacity of chemicals from Irwin and Nam Doc Mai mango peel to fight fat cell development to “a complex interplay of bioactive compounds unique to each peel extract, rather than just a single component”.

The research team acknowledges that more work needs to be done, both to identify the beneficial molecules and to find ways in which the peel can be incorporated into palatable foods.

Cook at Home to Prolong Life
Home-cooked meals are healthier than those bought in restaurants, at least in Taiwan according to E/Prof Mark Wahlqvist of Monash University’s Asia Pacific Health and Nutrition Centre. Cooking at home can result in a dramatic increase in life expectancy, Wahlqvist revealed in Public Health Nutrition.

Almost one-third of Taiwanese people aged over 65 and living independently reported preparing meals at home at least five times per week, while 43% never cooked at home. In a follow-up study conducted 10 years later, those who had cooked most often were 47% more likely to still be alive than those who never did.

“We found those that cooked more frequently had a better sense of nutritional knowledge than those who didn’t,” Wahlqvist said. “Cooking is an activity that requires both good mental and physical health. Besides the health benefits the actual cooked meal provides, there are other physiological benefits obtained from its production, purchase, preparation and eating, especially with others.”

Noisy Advance for Quantum Computing
Quantum computers could benefit from the addition of noise, says Dr Andre Carvalho of the ARC Centre for Quantum Computing in Physical Review Letters.

“We know how to correct errors in a quantum computer but we need to keep the noise level really, really low,” Carvalho says. “That’s been a problem, because to build a quantum computer you have to go down to atomic scales and deal with microscopic systems, which are extremely sensitive to noise.”

However, Carvalho found that adding noise allowed computational steps to proceed “provided you measure the system, keep a close eye on it and intervene”. The intervention operates like a ratchet, holding correct answers in place while others are allowed to re-occur.

“It’s like the idea that if you let a monkey type randomly on a typewriter, eventually a Shakespearean play could come out,” Carvalho says. “Imagine that whenever the monkey types the right character in a particular position you protect that position, so that any other typing will not affect the desired character.”

Knee Monitoring Soothes Pain
Better management of knee osteoarthritis may become possible as a result of new techniques to monitor the movements of sufferers.

Osteoarthritis in the knees already causes great suffering, and it is set to get worse with an ageing population forcing the lower body to bear increasingly heavy weights. Adjusting the gait to place less stress on the knees can be helpful (AS, July/Aug 2012, p.9), but the equipment required for detailed observations is expensive.

The University of Melbourne’s Department of Physiotherapy has partnered with Ericsson Australia to produce a set of inertial sensors, accelerometers and gyroscopes that a patient can wear to produce real-time data on movements in ordinary life. Transmitted via a smartphone to a server, this will allow medical professionals to track the behaviour most likely to cause pain and assist those suffering from arthritis to adjust and minimise symptoms.

Epilepsy Drug Risk
Patients taking anti-epileptic drugs are four times as likely as non-users to be diagnosed with osteoporosis and twice as likely to suffer falls, creating a major risk of broken and fractured bones.

Prof John Wark of the University of Melbourne’s Department of Medicine published the findings in Neurology. More than 70% of participants in the study professed no knowledge that epilepsy drugs could affect either bone mineral density or balance.

“Patients need to be offered better information to help them to avoid these risks and prevent injury,” Wark said.

The study was conducted on 150 outpatients at Royal Melbourne Hospital aged over 15 and taking antiepileptic drugs, with 506 controls.

Participants are being sought for trials of individuals taking drugs to treat epilepsy who have a sibling who is not.

Single Fibre Forensics
Crime dramas have a bad reputation for exaggerating the capacity of forensic technologies, but Flinders University students have demonstrated what is possible by extracting single fibres from a receipt to show that ink came from two different ballpoint pens, which indicates forgery.

“Until now, ink analysis samples were obtained by cutting a 5 mm by 8mm piece of paper or punching a 1.25 mm hole in the document,” said A/Prof Stewart Walker. “Obviously people who have got old documents or paintings don’t want you to come along and cut a bit out.”

Forensic Science International published Mr Broderick Matthews’ work on the extraction of fibres using tungsten wire and superfine tweezers, followed by chemical analysis.

The Carbon’s in the Meadows
Seagrass meadows store more carbon per hectare than forests, a paper in Nature Geoscience has revealed. In the face of global seagrass destruction this may prove bad news, but opportunities exist for revegetation.

While carbon storage measured in Florida Bay, Shark Bay and the Mediterranean Spanish Coast revealed a median of 14,000 tonnes of carbon/km2, the true figure may be higher. Most of the carbon was stored under the sea floor rather than in the living grasses, and most samples were only taken to a depth of 1 metre. In some cases the carbon stretched much further down.

Sea beds in the western Mediterranean were found with 83,000 tonnes/km2. In comparison, forests typically store 30,000 tonnes/km2.

Prof Gary Kendrick of the University of WA attributes the high storage to the fact that carbon on the sea floor is not subject to microbial recycling “unless subject to disturbance”. When sea grasses are removed or destroyed as a result of dredging operations, coastal development or turbidity, the carbon they have trapped over thousands of years can return to circulation.

An estimated 29% of the world’s seagrasses have been lost, and the rate is accelerating. While Australian legislation requires mitigation of any damage to seagrass beds, the enormous operations associated with mining and export of oil, gas and coal from northern Australia are subjecting huge areas to damage.

“The good news is if seagrass meadows are restored they can effectively and rapidly re-establish lost carbon sinks and stores as well provide a range of other valuable ecosystem benefits, including water quality protection, and as an important biodiversity habitat,” Kendrick says. For example, a study of a 16-year project to restore seagrass meadows off Albany in Western Australia has revealed 8 cm of sediment laid down, although Kendrick cannot reveal the carbon concentration at this stage.

Kendrick attributes the high concentration of carbon in the Spanish Mediterranean to Posidonia oceanica, the dominant species there, and warns that climate change may be pushing P. oceanica to its thermal limits within the largely closed sea.