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Browse Briefs

By Stephen Luntz

Brief bites of science news

Soft Drinks Affect Breathing
Soft drink consumption has been linked to higher rates of asthma and chronic obstructive pulmonary disease (COPD).

Dr Zumin Shi of Adelaide University used a computer-assisted telephone study of almost 17,000 South Australians to investigate the effect of consuming cola, lemonade, flavoured mineral water or sports drinks on the two conditions. Shi found that 10% of adults reported drinking more than 500 mL/day, and these people were 26% more likely to suffer from asthma and 70% more likely to have COPD.

The effects were more dramatic for smokers. Even those who smoke but do not consume soft drinks had rates of COPD 3.4 times higher than those who did neither. However, drinking small quantities of soft drink raised this to 4.3 times, and smokers consuming more than 500 mL/day were 6.6 times as vulnerable. Shi did not measure the impact of even higher consumption, but suspects it would be greater still.

The survey did not distinguish between those drinking sugared and diet varieties, so Shi says it is not possible to assess whether the effects are a result of the sugar content, carbonisation or some other factor.

Crocodile Hearts Get Treadmill Workout
The crocodile’s four-chambered heart is a candidate for the most advanced example of that organ in the animal kingdom. Dr Suzy Munns of James Cook University has been putting it through its paces by running crocodiles on treadmills.

Munns is testing the contribution of the hepatic piston pump, a thin muscle that is unique to crocodilians and thought to be the crocodile’s main breathing driver. By disabling the pump, Munn was able to show that the muscles of the rib cage are more important in inflating the crocodile’s lungs.

“Our study has shown that the hepatic piston pump is not essential for breathing,” Munns said. The hepatic piston pump does assist with breathing, however, and may also control rolling movements during dives.

While in danger of a nip, Munns was working with crocodiles weighing only 1.5 kg, limiting the risks of treadmill research.

Paternal Smoking Linked to Leukaemia
Fathers who smoke heavily around the time their children are conceived have a 35% greater chance of having a child with Acute Lymphoblastic Leukaemia (ALL), a study by the Telethon Institute for Child Health Research has concluded.

“The first step towards the development of leukaemia is thought to occur in utero in a lot of cases,” said lead author Dr Elizabeth Milne. “Tobacco is a known carcinogen and, in terms of childhood leukaemia, there’s a plausible biological pathway whereby paternal smoking could actually contribute to disease risk in the offspring.”

Comparison of 388 families where a child has ALL with 868 controls indicated that smoking more than 15 cigarettes per day posed a significant risk factor, but no risk was detected for light smoking or for previously heavy smokers who had quit by the time of conception.

“Oxidative damage to the DNA is the main type of damage seen as a result of smoking in sperm,” said Milne, although this is not yet confirmed as the immediate cause.

Smoking Leads to Infertility of Children
On the other hand, exposure to smoke as a child can reduce the chances of getting pregnant later.

“Our laboratory work has show that exposure to toxins by inhaling cigarette smoke during the early stages of life could lead to a reduction in the quality and number of eggs in females,” said Prof Eileen McLaughlin of the Hunter Medical Research Institute. She is seeking funding to see whether the same applies to exposure to tobacco in the womb.

McLaughlin’s work indicates the effects of smoking can be transmitted through several generations. “If you translate this to humans, it means that if your grandmother smoked – either while pregnant with your mother or near her when she was a baby – you and possibly your children may be at risk of reduced fertility.”

Tumour Scrambles Devil Genome
The facial tumour threatening Tasmanian devils jumbles their genome so that devils suffering from the tumour have chromosomes that look like badly completed jigsaw puzzles, Dr Janine Deakin of the Australian National University has found. Deakin also learnt that the cancer is evolving only slowly, having barely changed since the first examples were found 16 years ago.

“That’s really unusual for cancers because usually, for human cancers, evolution is rapid and the tumour will be completely different between the original tumour and its metastases. In this work we confirmed that the devil tumour is genetically very stable,” said Deakin.

The devils’ suffering may offer surprising benefits. “In humans, you are usually working with a rapidly evolving cancer and it’s hard to identify the important things because it’s all happening so fast. The devil is going to be a good model for looking at some human cancers because it is so stable. With everything happening slower we have a better chance of finding those things out,” said Deakin.

Better Drugs on the Nose
Computer modelling of the behaviour of particle flows within the nasal cavity could lead to more effective drug delivery.

Prof Jiyuan Tu of RMIT’s School of Aerospace, Mechanical and Manufacturing Engineering is applying computational fluid dynamics to the behaviour of particles from nasal spray devices to see how drugs behave.

“We have developed sophisticated models of the real respiratory airway from medical imaging techniques (CT and MRI) that includes the oral and nasal cavity, larynx, pharynx, trachea and the upper regions of the lung airway,” said Tu. “These areas of the respiratory airway are capable of determining how and where the inhaled particles and gases will move and eventually deposit onto the respiratory walls.”

Similar techniques have been used to work out how asbestos fibres reach deep into the lungs to do so much damage.

Screen Time Linked to Poor Body Image
It may be a hard message to sell, but teenage girls who spend more time doing homework and less on Facebook feel better about themselves and are less prone to depression, a Flinders University study has found.

“The same ideals that are presented about women’s bodies on TV and in magazines are also reflected on the Internet,” said Dr Amy Slater of the School of Psychology. “For instance, we found high levels of beauty products and weight loss ads on websites aimed at young girls.”

Her survey of 1100 adolescent South Australian girls found those in years 8 and 9 were spending 90 minutes per day on social networking sites, and that this time correlated with depression and negative feelings about their bodies.

On the other hand, girls who spent more time doing homework had a stronger sense of identity and less depression. “Body dissatisfaction consistently comes up as one of the biggest, most important issues for young people, and our research has shown that the alarming amount of time these girls are spending on the internet may have a huge impact on the way they think and feel about their bodies,” Slater said.

Tropical Stormwater Danger
The heavy rains of the past two wet seasons in northern Queensland may have posed an additional danger beyond the obvious ones. The bacterium Burkholderia pseudomallei, which is responsible for the disease melioidosis, or Nightcliff gardener’s disease, has been found in Townsville groundwater.

Melioidosis is associated with fever, pneumonia and sepsis, and has a reported mortality rate of 20% in Townsville. Although B. pseudomallei is known in the local soils, its discovery in groundwater by PhD student Anthony Baker of James Cook University is a first.

“This finding may help explain the reported infection peak during the wet season and after periods of extreme weather,” said A/Prof Jeff Warner. “Avoiding soil in the wet season is good, but avoiding run-off or storm water is perhaps even better.”

Science by Post
Victoria University has found a way to conduct ecological research cheaply, using a mix of wooden posts and crowd-sourcing.

Dr Martin Fluker has installed a series of posts in locations that attract bird watchers and tourists. The posts contain instructions to point a camera in a particular spot and upload a copy of the image to Fluker’s site (http://tinyurl.com/77sepud). These “Fluker Posts” allow for the collection of information regarding the species inhabiting the area for a fraction of the cost of a systematic survey.

“The success of this design is its simplicity,” Fluker said. “It has minimal set-up or maintenance costs yet delivers on the need for monitoring large and often remote natural environments.”

The latest site for the posts is the Werribee Western Treatment Plant, a Ramsar-listed wetland.

Super Atomic Clock
Atomic clocks using the orbit of electrons as a pendulum have allowed us to measure time with astonishing accuracy, but Dr Victor Flambaum says we can do even better.

In a paper published in Physical Review Letters Flambaum, Head of Theoretical Physics at the University of NSW, proposed a clock based on the motion of neutrons within the nucleus. “This is nearly 100 times more accurate than the best atomic clocks we have now,” Flambaum said.

Had such a clock been running from the beginning of time it would be wrong by less than one-twentieth of a second today. While such precision may seem an indulgence, Flambaum said the establishment of such a nuclear clock “would allow scientists to test fundamental physical theories at unprecedented levels of precision and provide an unmatched tool for applied physics research”.

Equine Nosebands Too Tight
Tight nosebands are increasingly being used to control horses in equestrian competitions, with disturbing results. According to Prof Paul McGreevy of The University of Sydney’s School of Veterinary Science, “Over-tightened nosebands put so much pressure on horses’ nose and mouth areas that they cause distress and obvious injuries to the horses”.

Riders in dressage competitions lose points if their horses open their mouths, and many are willing to injure their mounts to avoid this. “Nosebands designed to clamp the jaw shut very tightly – the so-called ‘crank nosebands’ – are only a fairly recent innovation in horse bridle design. Thirty years ago nosebands were largely aesthetic rather than functional,” McGreevy explains.

McGreevy has designed a standard taper gauge that provides stewards with an objective measure of noseband tightness. He is advocating its adoption in time for the London Olympics.

Croc Genome = Bigger Crocs
The genome of the saltwater crocodile has been sequenced, and the information revealed will be used to breed bigger and better crocodiles.

“It cost many millions of dollars and many years of work by a huge international collaboration to produce the first human genome sequence in 2002,” said Prof Chris Moran of the University of Sydney’s School of Veterinary Science.

“Now a complete genome sequence can be produced for a complex organism for several thousands of dollars and in a relatively few months of work. This is what has been achieved with the finalisation of the saltwater crocodile genome sequence.”

The 7-year wait for sexual maturity makes crocodile breeding expensive, so Darwin Crocodile Farm sponsored the research in the hope of finding genetic markers they can use to identify the most promising individuals at birth.