Monthly Archives: February 2011

Antioxidants: hype or… hazard?

Vitamin and mineral supplements are big business. So although the manufacturers make a lot of claims, can you really believe what they say?

Multivitamins complete a to z, 250 tablets (click to embiggen)
Bottle of multivitamin supplements, complete a to z (Photo by Mike1024, via Wikimedia Commons)
For that matter, how do you know whether to believe any claims about medical products? With the amount of money involved in the health industry, there’s, well, a bit of a temptation to shape the truth.

In mid-2009, an entire scientific journal, the Australasian Journal of Bone and Joint Medicine – put out by the prestigious publisher Elsevier – was found to be basically an advertising brochure for the pharmaceutical company Merck. It claimed to cover reviews of research, but all the reviews were all suspiciously favourable to Merck’s products.

(Shortly after, Elsevier revealed that another 5 Australian journals were also sponsored by pharmaceutical companies.)

So where do you turn for real, reliable medical research?

Continue reading Antioxidants: hype or… hazard?

Smells like teen romance

Birds do it. Bees do it. Even educated fleas do it. But do humans use pheromones to attract a mate?

Italian honeybee workers and guards gathered at the entrance to their hive (click to embiggen)
Italian honeybees (Apis mellifera ligustica) at the entrance to their hive. Many of the workers are 'fanning', which distributes a powerful homing pheromone from a gland on the bee's abdomen, and also helps to ventilate and cool the hive. (Photo by Ken Thomas, via Wikimedia Commons)
The answer seems to be “maybe”. But if we are attracted by scent, it may have more to do with finding our immune systems than anything else.

 

Studies have shown that we are more likely to be attracted to someone with different immunity to ourselves, presumably to give the broadest benefit to our potential offspring.

To find out more about why some people smell more attractive then others, and potentially how to test you and and your partner’s “olfactory compatibility”, read “The Smell of Love” in Psychology Today.

Pheremones and falling in love

A certain day in February tends to prompt an awful lot of people to wear their heart on their sleeve, so to speak, and declare their true feelings for someone. But what makes that one individual stand out from the crowd to become the object of such a response? Poets and philosophers have pondered this question through the ages,  and in recent times, scientists have set their sights on the issue, too.

Continue reading Smells like teen romance

More than a drop in the ocean

Brisbane’s floods in January have affected more than just the river and the land – now they are stretching out into Moreton Bay as well.

A visualisation of the flood plume in Moreton Bay (click to read more)
A visualisation of the flood plume in Moreton Bay (Image by Mitchell Lyons, UQ)

The increased flow of fresh water and sediments has the potential to damage seagrass and other life in the bay’s ecosystem.

A team from the University of Queensland’s School of Geography, Planning and Environmental Management are helping to monitor the flood plume and any ensuing damage using photos from both divers and satellites, as well as wireless underwater sensors.

The project leader, Associate Professor Ron Johnstone, said:

“We have already observed the death of algae and bivalves and the sensors will be able to record accurate and real time measurements of other changes in the marine environment as a result of the floods.

“This information will help us understand how the floods are impacting on life in the bay and what it is that is causing some of the plants and animals to die.”

For more on this project, see the Joint Remote Sensing Research Program and the Smart Environmental Monitoring and Analysis Technologies Project at the University of Queensland.

Seismology of the Christchurch earthquake

I’m sure that many of you, like me, have been shocked by yesterday’s tragedy in New Zealand. Christchurch is a beautiful city, which I’ve been fortunate enough to visit twice in the past year – my thoughts are with all those affected, especially those who’ve lost loved ones or are still trapped in the rubble.

Unfortunately, science still can’t predict when earthquakes are going to strike. But we do know why they happen, and we learn more each time.

Map of the Earth, showing the tectonic plates (click to embiggen)
Map of the Earth's tectonic plates. Notice New Zealand is right where the Pacific and Australian plates collide. (Image by USGS, via Wikimedia Commons)
Continue reading Seismology of the Christchurch earthquake

Ashes to ashes

What happens to you when you die?

Specifically, what happens to you when you die and are cremated? Well, cremation uses furnaces that reach temperatures of around 760–1150 °C. Fire this hot vapourises almost all the tissue in the body, and what remains is mostly former bones.

The mineral in bone is hydroxylapatite, a type of calcium phosphate with the formula Ca5(PO4)3(OH). But in the heat of cremation, it’s at least partly transformed into tricalcium phosphate, or Ca3(PO4)2.

Scanning electronic micrography of deproteined rat bone x10000 (click to embiggen)
Scanning electronic micrography of bone mineral at 10000x magnification (Image by User:Sbertazzo, via Wikimedia Commons)
There isn’t a lot of tricalcium phosphate left in cremated human remains (or “cremains”, if you prefer), only about 3.5% of the body’s original mass. And it isn’t really harmful to the environment; if anything, calcium phosphate makes a good fertiliser.

It also occurs naturally in cow milk and is used as food additive E341(iii) in table salt, sugar and baking powder, to stop it clumping together. But don’t worry: the food additive isn’t normally made from bones. That would be gross.

Continue reading Ashes to ashes

Arsenic-based lifeforms? Really?

First of all, a NASA astrobiologist, Felisa Wolfe-Simon, and her team found some bacteria in Lake Mono, in California.

Felisa Wolfe-Simon processing mud from Mono Lake to inoculate media to grow microbes on arsenic (click to embiggen)
Felisa Wolfe-Simon processing mud from Mono Lake to inoculate media to grow microbes on arsenic (Image by Henry Bortman, via NASA)

This lake has very high salinity, high alkalinity and high levels of arsenic. Dr Wolfe-Simon’s team extracted a strain of  Gammaproteobacteria, which they cultivated in a laboratory and called GFAJ-1 (short for “Give Felisa a job”).

When they cut off the bacteria’s supply of phosphorous – essential for DNA, cell membranes and other metabolic processes – it continued to grow. This led them to conclude that arsenic – which, although usually poisonous, is chemically similar to phosphorous – had taken its place.

Then NASA put out an announcement…

Continue reading Arsenic-based lifeforms? Really?

What happens inside a cocoon?

If you were an alien arriving on Earth who was shown a caterpillar and then a butterfly, you probably wouldn’t think they were one and the same.

How exactly does it happen? How does this this squishy, multi-legged, soft thing become a flying insect with an exoskeleton?

It’s all a question of metamorphosis – in particular, insect metamorphosis.

Luna moth, Actias luna, emerging from silk cocoon (link to insect metamorphosis on Wikipedia)
Luna moth, Actias luna, emerging from a silk cocoon (Taken by Shawn Hanrahan)

Continue reading What happens inside a cocoon?

Hey, you got the fever?

Always one to sniff out a good story, this week Stuart let us in on the facts behind plant pollen allergies and hay fever, otherwise known as allergic rhinitis. Not to mention the horror that is rhinorrhea (that’s actually just the technical term for a runny nose, but it sounds pretty horrific).

Not all plant pollen causes allergic reactions, only that carried by the wind, which usually means you don't even notice the flowers. Shape is often an indicator of how pollen is spread. This pollen is magnified under an electron microscope by about 500x actual size (Photo from Dartmouth Electron Microscope Facility)

Although there’s a tendency to blame wattles and other showy flowers for our pain, those are unlikely to be responsible because they’re pollinated by insects. It’s much more likely to be due to the less obvious, wind-pollinated plants like grasses, that cast their pollen on the air.

To find out which plants cause hay fever and what time of year to avoid them, see the Australian Society of Clinical Immunology and Allergy’s Guide to common allergic pollen.

And for further information on hay fever symptoms and treatment options, check out the Better Health Channel.

Continue reading Hey, you got the fever?

Deep, deep science

John, who always likes to seek out extremes, this week dug up the Kola Superdeep Borehole, the deepest hole ever drilled at 12.262 km beneath the Earth.

Although they reached this depth in 1989, drilling actually began 19 years earlier in 1970, when Russia was part of the Soviet Union.

The borehole sits on and under the Kola Peninsula, in Lapland at the very north-west of Russia, and part of Murmansk Oblast (word of the day: oblast, an administrative division or province of Russia and other Slavic countries like Ukraine and Belarus. Present-day Russia has 46 oblasts, as well as various republics and krais, or territories).

Kola Superdeep Borehole, commemorated on the 1987 USSR stamp
Kola Superdeep Borehole, commemorated on the 1987 USSR stamp (Scanned and processed by Mariluna, via Wikimedia Commons)
You can read more about this Russian marvel at Wikipedia.

Bacteria with guts

In this week’s show, Beth discussed a recently published study on how probiotics, the “good bacteria” in your gut, help with digestion, boost the immune system and possibly reduce the risk of cancer: Fukuda S, Toh H, Hase K, Oshima K, Nakanishi Y, Yoshimura K, Tobe T, Clarke JM, Topping DL, Suzuki T, Taylor TD, Itoh K, Kikuchi J, Morita H, Hattori M & Ohno H 2011,”Bifidobacteria can protect from enteropathogenic infection through production of acetate”, Nature, vol. 469, no. 7331, pp. 543-547.

Gram staining of Bifidobacterium adolescentis (click to embiggen)
Bifidobacterium adolescentis (Gram staining by Y tambe , via Wikimedia Commons)
This study was a collaboration between Japanese researchers and Australian scientists from the CSIRO. The paper’s Australian co-author, Dr David Topping from CSIRO Food Futures and Preventative Health Flagships, said of the research:

“While protection was shown with probiotic Bifidobacteria, the study showed also that a CSIRO technology being developed in Preventative Health Flagship was also highly effective. This product is a modified starch which delivers specific SCFA to the large bowel and the data confirm that acetic acid was critical for survival of infected animals. The studies offer promise for the development of more effective prebiotic and probiotic foods to assist in infection control.

For more on this study, read the story at ABC Science.