David Bradley – Page 327

Photochemistry without light

Infrared and nuclear magnetic resonance spectroscopy are anything but child’s play, but now US chemists have used these techniques to follow the chemistry of “light sticks” and to develop a light-free version of photochemistry. This contradiction in terms could be exploited in a remote cure process for photopolymers, they say, allowing inaccessible cracks in pipes, joints or containers, to be sealed as well as having other practical applications in coatings, paints, varnishes, adhesives and sealants.

Light sticks hold children’s parties in awe with their eerie yellow-green glow as well as providing emergency lighting without electricity or a naked flame. The chemistry taking place when the stick is “snapped” and the materials mix involves oxalyl chloride and hydrogen peroxide reacting in the presence of a fluorophore, which emits light as the reaction proceeds.

Read the full story in the latest news round up from David Bradley on SpectroscopyNOW.com

Ask Jeeves about science

Here’s a top listing of questions that bring readers to sciencebase from the Ask Jeeves search engine. We cannot promise to answer them all here, but search the site and you may find enlightenment or at the very least some factlets of even more interest.

How old was Einstein when he wrote his papers on relativity?
When were the largest glaciers in history?
Where can I find some wow facts about sodium?
When Mars will look as large as the full Moon to the naked eye?
How much does the Japanese government spend on computers?
What planet is most like Earth?
How many barrels of oil do Americans use every day?
What is the width of a dime?
Why can’t frogs smoke?
How far is Sedna from the sun?
How do humans recognize faces?
What killed Otzi the iceman?
Where is the Earth’s crust thickest?

Resurrecting Pluto

As Sciencebase reported recently, a session of the International Astronomical Union (IAU), meeting in Prague, during August passed a resolution re-defining the nature of the planets of our solar system. Apparently, only about 428 of the IAU’s almost 10000 membership was involved in the voting. The original proposal would have led to an expansion of our solar system from the familiar nine planets to 12, for now. But, as we now know things turned out very differently.

This proposal was modified at the conference, with the aim being to exclude from the definition of planet all but the eight largest planets, which meant Pluton was dwarved. The vote leaned towards this definition, much to the chagrin of the wider IAU community, which believes neither definition was subject to critical review by the broader planetary
science community prior to the conference, despite simple means to do so.

A grass roots petition stating: “We, as planetary scientists and astronomers, do not agree with the IAU’s
definition of a planet, nor will we use it. A better definition is needed” has now emerged – http://www.ipetitions.com/petition/planetprotest

According to a press release from the Planetary Science Institute, in less than five days more than 300
professional planetary scientists and astronomers had signed the petition. “The list of signatories includes researchers who have studied every kind of planet in the solar system, as well as asteroids, comets, the Kuiper Belt, and planet interactions with space environment. They have been involved in the robotic exploration of the solar system from some of the earliest missions to Cassini/Huygens, the missions to Mars, ongoing missions to the innermost and outermost reaches of our solar system, and are leading missions preparing to be launched,” says the release.

The list also includes prominent experts in the field of planet formation and evolution, planetary atmospheres,
planetary surfaces and interiors, and includes international prize-winning researchers.

“This petition gives substantial weight to argument that the IAU definition of planet does not meet fundamental scientific standards and should be set aside,” states petition organizer Dr. Mark Sykes, Director of the Planetary Science Institute in Tucson, Arizona. “A more open process, involving a broader cross section of the community engaged in
planetary studies of our own solar system and others should be undertaken.”

So, as we predicted, Pluto’s status could be changed yet again. Meanwhile the guy on the Clapham omnibus will probably stick with the idea that Pluto is a planet regardless of the outcome of this debate.

Premature diagnostics

An MRI scan can help in predicting future developmental outcomes of pre-term infants, according to US researchers. The scan reveals abnormalities no picked up by cranial ultrasound and can be used to predict problems that would become apparent by age two years.

Terrie Inder of Washington University School of Medicine in St Louis working with colleagues in New Zealand and Australia have discovered that MRI can reveal brain abnormalities in very premature babies born at 30 weeks or less. They monitored 167 pre-term infants from birth to age two years having graded these abnormalities to see if there is a correlation with any severe delays in cognitive and psychomotor development, cerebral palsy, or hearing or visual impairments in the two-year olds.

Read on…

Chitika

No doubt I’ll get round to creating a Chitika stream for my readers viewing pleasure. But, first, just check out the blurb with which they try to entice bloggers:

“Chitika eMiniMalls bring life to product promotion on the web. With eMiniMalls you can hand-select specific products (or product categories) targeted to the content of your webpage, and provides your users with robust comparative shopping information to make an informed buying decision – before they leave your site. As users click, you make money.”

Unfortunately for a science blog and its readership, they don’t yet have a minimall for silica gel TLC plates and test-tubes, maybe one day.

Periodic Post

Periodic table of sex

Mosts chemists get to see some wacky periodic tables during their careers – circular ones, spiral ones, ones that rearrange all the elements etc etc. Then there are the foody ones and then there are the giant periodic tables, the arty farty ones, the online version, the flash table.

And, then there’s the periodic table of sex.

I didn’t think it was real at first, but several sciencebase visitors have been searching for this incredible object during the last few days, so I thought I’d uncover the truth. Apparently, just such a PT exists, its elementary in the most lewd way, but is available from Amazon. Apparently, allposters.com have stopped selling it, so I’d grab one while you can: Periodic table of sex

It’s not every post I get to categorise as chemistry, sex and geek all at the same time, but this one was simply begging for it. I hate to think what good-ole Dmitri Mendeleev would have made of it though, but surely it’d make the perfect gift for the chemistry student in your life. Wouldn’t it?

Natural power for TV

A posting about telemarketing on digg reminded me how a teacher friend used to mess with the heads of cold callers, asking them obviously dumb questions.

One of the less subtle was to ask the telemarketer from British Gas, which now also offer electricity as well as natural gas to UK customers, whether he’d be able to run his TV from the gas supply.

They caller would politely tell him no, but become increasingly frustrated as my friend continued his line of enquiry embellishing his questions all the while with thermodynamic gobbledegook and nonsense about improved efficiency. He could keep them hanging on for hours…

Of course, the irony is that once we all have methane-fed fuel cells in our homes, we will indeed be running our TVs off natural gas!

Glucosamine hydrochloride

The UK’s Food Standards Agency announced (August 21, 2006) that it has received an application from a food additive manufacturer to use glucosamine hydrochloride in a range of foods, including smoothies and sports drinks. The company, Cargill, makes glucosamine hydrochloride from the black mould Aspergillus niger.

But, why would they want to do this? Cargill wants to use its glucosamine as an ingredient in a range of pasteurised food products. These will include fruit juices and fruit juice products, such as tomato, tomato mixtures and fruit; smoothies, dehydrated instant drink mixes, fermented milk-based products, such as yoghurts and fromage frais, sports drinks and iced tea drinks.

Glucosamine has an almost mythical status among sufferers of various types of joint pain as a product that can supposedly ease their suffering. It gets this reputation from the fact that it is a naturally occurring amino-sugar that acts as a major building block of complex proteins called glycosaminoglycans, which form part of the structure of cartilage. As such, people with arthritis and other disorders that affect the joints hope that ingesting large quantities of this compound will somehow help their bodies to self-repair. This chain of causality has not been demonstrated.

Indeed, a recent study published in Nature Clinical Practice Rheumatology (2006, 2, 356-357) reported that:

“The publication of the results from the GAIT (Glucosamine/Chondroitin Arthritis Intervention Trial) represents a milestone for evidence-based therapeutics in OA. This large, NIH-funded, multicenter trial showed that neither chondroitin, glucosamine, nor the combination, was more efficacious than placebo for the treatment of pain in OA. The absence of efficacy was demonstrated both for the primary outcome, and for nine preselected secondary outcomes. The positive control, the COX2 inhibitor celecoxib, showed efficacy compared with placebo.”

Cargill’s glucosamine is produced through chitin sourced from Aspergillus niger, whereas all other known commercial glucosamine products are derived from shellfish, so there really won’t be any difference between their additive and the glucosamine present in a whole range of products at this time.

But, the myth of glucosamine is just that, or so it that large-scale study would suggest. A conventional diet will usually provide all the necessary precursors for this compound, so unless you’re malnourished and you’d then be experiencing other symptoms too, it is unlikely that adding glucosamine to your diet will ease your joint problems.

If the FSA sees fit to approve glucosamine hydrochloride from A. niger, UK consumers can expect to see a whole new rash of drinks with this additive purporting to help the aged and those with joint and related problems. They will not be able to make any serious medical claims about the product, but will almost certainly be able to ramp up the price nevertheless.

My advice? Stick to that healthy diet and drink plenty of tap water (if you don’t like the taste fill a jug and leave uncovered in the fridge for an hour or two before drinking to allow volatile chlorine compounds to escape.

Sunscreen and skin damage

When I first wrote about the doubts scientists were raising concerning sunscreens in Chem & Industry magazine some time in the early 1990s, it seemed that the findings would simply confuse consumers and cause a storm among manufacturers. Unfortunately, that doesn’t seem to be the case, sun worshippers carried on frying themselves, slapping on only meagre amounts of purportedly protective cream, partly out of laziness and partly because it is just so expensive and manufacturers continued to sell their products by the bucket load. Then research emerged that showed lack of sun exposure not only risks rickets but could increase the chances of you getting internal cancers, as opposed to the much feared skin cancer. As if consumers were not confused enough.

Now, US researchers have shown that applying too little suncream can actually turn the UV-absorbing chemicals against you.

When skin is exposed to sunlight, ultraviolet radiation (UV) is absorbed by skin molecules that then can generate harmful compounds, called reactive oxygen species or ROS, which are highly reactive molecules that can cause “oxidative damage.” For example, ROS can react with cellular components like cell walls, lipid membranes, mitochondria and DNA, leading to skin damage and increasing the visible signs of aging. The link with skin cancer itself is actually not so clear cut as some lobbyists claim.

However, when sunscreen is applied to the skin the UV filters in the sunscreen, reduce the amount of UV radiation penetrating the skin. Over time, though, the filters themselves are absorbed by the skin leaving the surface vulnerable to UV once more. The UV filters (octylmethoxycinnamate, benzophenone-3 and octocrylene) widely used in sunscreens themselves generate reactive oxygen species (ROS) in skin when exposed to ultraviolet radiation, augmenting the ROS that is naturally produced. [These new results are similar to those on which I reported in C&I ten years ago, DB]

Kerry Hanson of the University of California Riverside and colleagues now report that these three UV filters only work well if sunscreen is reapplied frequently to prevent ultraviolet radiation from reaching these filters. Without reapplication, these compounds could be just as harmful as not using sunscreen at all.

The team will publish their findings in a forthcoming issue of Free Radical Biology & Medicine.

“Sunscreens do an excellent job protecting against sunburn when used correctly,” said Hanson, who works in the laboratory of Christopher Bardeen, an assistant professor of chemistry at UCR. “This means using a sunscreen with a high sun protection factor and applying it uniformly on the skin. Our data show, however, that if coverage at the skin surface is low, the UV filters in sunscreens that have penetrated into the epidermis can potentially do more harm than good. More advanced sunscreens that ensure that the UV-filters stay on the skin surface are needed; such filters would reduce the level of UV-induced ROS. Another solution may be to mix the UV-filters with antioxidants since antioxidants have been shown to reduce UV-induced ROS levels in the skin.”

“For now, the best advice is to use sunscreens and re-apply them often — the Skin Cancer Foundation recommends every two hours, and especially after sweating or swimming, which can wash away sunscreen — to reduce the amount of UV radiation from getting through to filters that have penetrated the skin,” Bardeen said. “This, in turn, would reduce ROS generation.”

But, having read this please also read my write-up on how to sunbathe safely

Pluto dwarved

Well, the votes were counted and the decision made: Pluto was demoted to less than planetary status. The astronomy and science textbook publishers are rubbing their hands with glee as new editions will have to be printed and plucked from their shelves by eager homeschoolers and teachers keen to get their facts right.

Unfortunately, things are never so clear cut.

A fierce backlash has begun against the decision has begun, says the BBC. The lead scientist on NASA’s robotic mission to Pluto, Alan Stern, called the ruling “embarrassing”, while the chair of the committee, Owen Gingerich, implied that the vote had been “hijacked”.

http://news.bbc.co.uk/1/hi/sci/tech/5283956.stm

It seems, however, that many of those arguing against the demotion of Pluto to dwarf planet status had already left the meeting because of other commitments before the final voting took place. Indeed, only 10% of the 2700 delegates at this meeting actually voted!

Gingerich, was among the 90% who couldn’t vote as he had to return to the US. He says electronic balloting must be introduced in the future. Stern too was unable to vote, “I was not allowed to vote because I was not in a room in Prague on Thursday 24th. Of 10,000 astronomers, 4% were in that room – you can’t even claim consensus,” he told the Beeb.

This left the anti-Plutonists with an open field to throw this tragic rock into a lower orbit.

Stern expressed even further consternation but added that he could not see the resolution standing for very long and wasn’t planning on editing the manuscript for his forthcoming astronomy textbook just yet.

Caltech’s Mike Brown, co-discoverer of UB313 is quite happy to live in a solar system with just eight planets thought. “Eight is enough,” he told the Associated Press, jokingly adding: “I may go down in history as the guy who killed Pluto.”

Whichever way the solar count finally goes, it seems that the arguments are adding a frisson to astronomy that has been sadly lacking for many years. Even if the textbooks stay the same, bookshops would be well advised to stock up early for the Christmas rush as a whole new wave of budding astronomers clamber for space books and maps of the night skies.