Reactive Chemistry BlogReactive Chemistry Blog

What is ambergris?

David Bradley — Wed, 03 Apr 2013 08:34:01 +0000

Ambergris (ambergrease or grey amber) is a waxy, inflammable solid with a dull grey colour formed as a biliary secretion in the gut of sperm whales. It is thought to act as a protective lubricant so that squid beaks and other hard, sharp ojects the whale may swallow don’t pierce its intestine.

Its main use was as a fixative in perfumes. Alluded to in the Rush song Panacea from their 1975 album Caress of Steel in the line:

I catch the scent of ambergris and turn my head, surprised

Fresh ambergris actually has an oceanic, fecal odour when first expelled by the whale, but happily acquires a sweet, earthy scent commonly not dissimilar to the smell of rubbing alcohol but without the “chemical” astringency, which presumably was what turned Geddy’s head, not the smell of whale poo.

According to its Wikipedia entry, ambergris is relatively non-reactive to acid. White crystals of ambrein can be separated from ambergris by heating raw ambergris in alcohol, then allowing the resulting solution to cool. Ambrein is fairly odourless but breaks down to ambrox and ambrinol, which give it its characteristic sweet scent.

Today, ambergris has been replaced by synthetic agents, such as ambroxan. However, 83 kg of ambergris in the intestine of a recently stranded whale is estimated to be worth €500,000.

Lead paint still on sale in Africa

David Bradley — Tue, 26 Mar 2013 14:44:17 +0000

Paint containing dangerous amounts of lead is on sale in Cameroon, a study has found. Moreover, the subsidiaries of large multinational companies were among those found to be selling this paint.

via Lead paint still on sale in Africa | Chemistry World.

Antioxidant backlash redux

David Bradley — Thu, 10 Jan 2013 16:40:50 +0000

According to Henry Scowcroft of Cancer Research UK writing in The Guardian: “Large studies have repeatedly shown that, with the possible exception of vitamin D, antioxidant supplements have negligible positive effect on healthy people, at least in terms of important things such as preventing people getting cancer or dying prematurely. And some supplements – notably vitamins A, E and beta-carotene – even seem to slightly raise the risk of disease and early death.”
The antioxidant myth is too easy to swallow.

I’ve been saying as much for years, and was quoted from a short blog post here in Newsweek a couple of years ago in an article about the antioxidant backlash. It caused quite a shtstorm at the time with all sorts of CAM quacks crawling out of the woodwork to slag me off. Quite bizarre really given that the quote was a throwaway remark in a very short blog post and not a full critique of the state of research into antioxidants at all.

Antioxidant supplements are big business, but they promise an elixir of life that is, it seems, really not supported by scientific evidence and repeatedly advertisers come unstuck when they make overblown and hyperbolic claims about the benefits of this or that product.

Scowcroft points out that we seem to cling to the idea of panaceas and elixirs because the alternative is a bitter pill to swallow. If any life changes can overcome genetics and environmental factors then they are: Don’t smoke. Stay in shape. Eat a balanced diet. Limit alcohol intake. Keep active.

Now, who wants to do that instead of just popping a few daily pills?

Strong test for FUR

David Bradley — Thu, 10 Jan 2013 08:43:05 +0000

A new spectroscopic method has been developed for the determination of the drug furosemide used to treat congestive heart failure and other conditions. The drug is alsosed illegally by some athletes as a stimulant and rapid weight-loss agent.Yali Liu, Huijuan Wang, Jian Wang and Yuanfang Li of Southwest University, in Chongqing, China, explain how furosemide 4-chloro-N-furfuryl-5-sulfamoyl-anthranillic acid, FUR is a potent diuretic. It is widely used in the treatment of chronic kidney failure, high blood pressure, congestive heart failure and cirrhosis of the liver. Its effects are correlated directly with administered dose as too are its side-effects. Testing for FUR.

Deceived Wisdom

David Bradley — Wed, 19 Dec 2012 08:30:04 +0000

British science journalist and owner of the Reactive Reports chemistry site, David Bradley, has published his first popular science book – Deceived Wisdom with UK publisher Elliott & Thompson. The book is available in hardback (UK) and electronic editions (RoW). You can order a copy now with free shipping and 48h dispatch for delivery almost anywhere in the world from Book Depository, use this link for 30% discount.

The book has had several 5-star reviews on amazon and elsewhere: TV personality Francis Wheen described Deceived Wisdom as his “dream book”, chemistry prof John Emsley says its “well written and engrossing,” while thriller writer KD George says, “it’ll be a great stocking filler. It’s science, it’s information, but it’s fun!”

Another amazon reviewer, “Eye Book”, had this to say: “David Bradley, a top science writer based in the UK puts a plethora of common misconceptions under his microscope and shows you why the stuff that you thought was right is really rubbish. Written with a light and humorous touch, reading `Deceived Wisdom’ will enable you to shoot down dinner-party bores, win endless quiz shows when Stephen Fry invites you to star in `QI’ and generally educate yourself beyond the misinformation doled out in primary and secondary schools (and probably quite a few universities.)”

Pumping bacterial toxins

David Bradley — Fri, 07 Sep 2012 06:51:50 +0000

In a previous issue, we discussed early work on Escherichia coli as a proof of principle for understanding how bacterial resistance to antibiotics can emerge. Now, Edward Yu’s team at Iowa State University have taken another step forward in our understanding of this pressing issue by using crystallography to reveal the structure of a protein regulator that controls the expression of the multidrug efflux pump in Mycobacterium tuberculosis.

via TB or not TB: Efflux X-rayed – Ezine – spectroscopyNOW.com.

1000 disease protein structures

David Bradley — Mon, 18 Jun 2012 09:52:52 +0000

An interdisciplinary study hinging on X-ray crystallography and nuclear magnetic resonance studies has examined 1000 proteins from more than 40 different human pathogens, including those responsible for plague, anthrax, salmonella, cholera, tuberculosis, leprosy, amoebic dysentery and influenza.

Researchers at the Center for Structural Genomics of Infectious Diseases (CSGID) and the Seattle Structural Genomics Center for Infectious Disease (SSGCID) marked the 1000-structure milestone in June and suggest that the data collected and interpreted will open up paths to novel pharmaceuticals, possible vaccines and other interventions for what are some of the most lethal organisms humanity must face.

via Protein millennium: 1000 structures by XRD and NMR – Ezine – spectroscopyNOW.com.

Helical light

David Bradley — Fri, 15 Jun 2012 07:09:07 +0000

Researchers have known for some time of monochromatic light beams, such as Laguerre-Gauss beams, which carry orbital angular momentum also have a helical phase profile. According to Ole Steuernagel of the University of Hertfordshires Science and Technology Research Institute, UK, have helical wave fronts and can be made visible using interferometry. Such dark helices can be generated at higher resolution than light helices and so could be used to etch helical channels through new materials to create a molecular sieve with a left or right handedness for filtering chiral molecules such as pharmaceuticals.

I asked Steuernagel about the next step in this work and he conceded that, “I sort of hop around and am currently working on a peculiar quantum transport phenomenon, not really connected with the helices.” However, he added that, “If I have another idea about the helices I might return to it. I have done a bit of other stuff on what you might call sculpted light fields. So, quite likely I will come back to this.”

“I just like to tinker and play with theory,” he told me. “I am not an experimentalist and so all I can say is, someone will want to use helical light to make handed materials and perhaps the other applications I mentioned. I would be very happy to see my stuff applied. Maybe the underlying message is more important, the one about the resolution limit being circumvented…that and he possibility of dark patterning.”

via Helical light: Interference and tweezers

Recognizing chemical hazards

David Bradley — Thu, 14 Jun 2012 08:20:47 +0000

“Memorize the pictograms” is really the take-home point. To that end, it’s important for people to recognize the distinctions between them. The two groups that I think require particular attention are the three health-related pictograms (human profile, exclamation mark, and skull and crossbones) and the flammables and oxidizers (flame and flame over circle).

via Recognizing chemical hazards | The Safety Zone.

Algae burn for you

David Bradley — Mon, 16 Jan 2012 16:36:27 +0000

Finding sustainable alternatives to fossil fuels that would both solve the problem of dwindling supplies of oil and cut the net carbon dioxide emissions from vehicles running on hydrocarbon fuels is a cause high on the environmental agenda. The use of biomass as a source for fuels compounds has benefits, but the setting aside of the great tracts of land required to “grow” adequate crops for conversion into biodiesel detracts from a parallel agenda of major concern: land use and food security.

Now, Johannes Lercher and his colleagues, Baoxiang Peng, Yuan Yao, Chen Zhao, at the Technische Universität München have developed a new catalytic process that might offer a solution to both problems. Their catalyst can efficiently convert biomass, or more properly biopetroleum, generated by microalgae into diesel fuels for use in suitable vehicles.

David Bradley on SpectroscopyNOW.com.