Arlene Weintraub, Author at 91av Science news and science articles from 91av Fri, 11 Aug 2017 11:23:07 +0000 en-US hourly 1 https://wordpress.org/?v=7.0.1 242057827 Sex, health, muscle, sport: Testosterone myths busted /article/2005137-sex-health-muscle-sport-testosterone-myths-busted/?utm_campaign=RSS|NSNS&utm_content=currents&utm_medium=RSS&utm_source=NSNS Mon, 07 Jul 2014 10:47:00 +0000 http://dn25854 Sex, health, muscle, sport: Testosterone myths busted

(Image: CHI-Photo/Tom Parker/Rex)

When easy-to-apply topical testosterone treatments such as skin patches and gels began hitting the market in the early 2000s, testosterone took on a whole new persona as a cure-all for anything that might ail the ageing male, from erectile dysfunction to unwanted body fat. Sales rocketed: between 2000 and 2011, prescriptions for testosterone supplements in the US more than quadrupled and in 2011 an estimated 5.3 million prescriptions were issued. Although nowhere near US figures yet, sales of testosterone supplements in the UK, Australia and Germany are also on the increase. But what’s the truth behind the hype?

Read our in-depth article:Man up: Is testosterone an elixir of youth?

Claim: Testosterone will boost your sex drive and correct erectile dysfunction

Fact: Studies have found that testosterone supplements produce only a moderate increase in libido and have virtually no effect on erectile dysfunction or overall sexual satisfaction in men. The theory that testosterone might improve female libido is also far from proven. A testosterone patch developed for women was rejected by the US Food and Drug Administration in 2004 because it had little impact on sexual desire, and carried potential cardiovascular risks

Claim: If you feel tired, your testosterone may be running low

Fact: None of the trials of marketed testosterone supplements were designed to measure fatigue. A one-year study currently being run by the National Institutes of Health is assessing the hormone’s impact on vitality and anaemia, but data won’t be out until late 2014

Claim: Testosterone supplements will make you stronger and leaner

Fact: Studies of testosterone supplementation have shown that although it produces a slight increase in lean body mass, and decreases fat mass by up to 2 kilograms, testosterone causes no change in overall body weight when compared with placebo

Claim: Testosterone improves sporting prowess

Fact: Some trials have shown small increases in muscle mass and slight improvements in grip strength with testosterone supplementation. The hormone also raises red blood cell counts, which may boost the amount of oxygen carried in the blood. However, studies measuring the hormone’s effects on lower limb strength and overall physical function have produced inconsistent results

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Man up: Is testosterone an elixir of youth? /article/2004716-man-up-is-testosterone-an-elixir-of-youth/?utm_campaign=RSS|NSNS&utm_content=currents&utm_medium=RSS&utm_source=NSNS Wed, 02 Jul 2014 17:00:00 +0000 http://mg22329760.600 2004716 Sniffer mice have a nose for explosives /article/1957120-sniffer-mice-have-a-nose-for-explosives/?utm_campaign=RSS|NSNS&utm_content=currents&utm_medium=RSS&utm_source=NSNS Wed, 02 Feb 2011 18:00:00 +0000 http://mg20927985.700 Is that a bomb I smell before me?
Is that a bomb I smell before me?
(Image: Barrie Watts/Alamy)

ONE day, there may be more than X-ray machines and full-body scanners awaiting you at the airport. Listen out for the snuffling of sniffer mice as you pass through security.

The critters will not be angling for a snack, though. They are part of a bomb-detecting unit created by Israeli start-up company BioExplorers, based in Herzeliya, which claims that trained mice can be better than full-body scanners and intrusive pat-downs at telling a bona fide passenger from a terrorist carrying explosives.

Eran Lumbroso conceived the mouse-based explosives detector while serving as a major in the Israeli navy. Along with his brother, Alon, he founded the company and built a device that looks much like an average airport metal detector or full-body scanner.

Along one side of an archway, a detection unit contains three concealed cartridges, each of which houses eight mice. During their 4-hour shifts in the detector, the mice mill about in a common area in each cartridge as air is passed over people paused in the archway and through the cartridge. When the mice sniff traces of any of eight key explosives in the air, they are conditioned to avoid the scent and flee to a side chamber, triggering an alarm. To avoid false positives, more than one mouse must enter the room at the same time.

“It’s as if they’re smelling a cat and escaping,” Eran says. “We detect the escape.” Unlike dogs, which are often trained for explosives and drugs detection, mice don’t require constant interaction with their trainers or treats to keep them motivated. As a result, they can live in comfortable cages with unlimited access to food and water. Each mouse would work two 4-hour shifts a day, and would have a working life of 18 months.

What’s more, mice beat dogs for olfactory talent, and by much more than a nose: dogs have 756 olfactory receptor genes, while mice have 1120, resulting in a more acute sense of smell.

Attacks such as the recent bombing of Domodedovo airport in Moscow, Russia, are fuelling interest in exploring new methods for keeping travellers safe. Low-tech alternatives may appeal to people who fear new full-body scanners are exposing them to harmful radiation and invading their privacy. “Animals’ noses are always a good solution, and the mice don’t see you naked,” says Bruce Schneier, who runs the blog .

However, Schneier adds that there are drawbacks that could prevent their widespread use. For instance, their cages need regular cleaning, and new mice would have to be trained all the time because of their short working life. And while useful for explosives, they could never replace current baggage scanners and metal detectors.

Nonetheless, the company ran its first field test in December last year at Azrieli Center, a large shopping mall in Tel Aviv. More than 1000 people passed through the detector, 22 of whom were asked to hide mock explosives in pockets or under shirts. All 22 packages were detected, the Lumbrosos claim, adding that the false-alarm rate was less than 0.1 per cent.

Like a moth to an explosive

Moths have an exquisite sense of smell, so their ability to sniff out improvised explosive devices was by Andrew Myrick and Tom Baker at Pennsylvania State University in University Park.

The team built a detector using four live moths which were immobilised in thin, aerated tubes.

Different chemicals produce distinct voltages on the antennae that the moths use to sense aromas, so the team wired up the moths to record these levels.

Software inferred the explosive source’s direction and distance based on the strength of signals coming from the insects. The detector was then able to home in on it to within 20 centimetres from 23 metres away.

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