Chemistry – Page 53 – David Bradley

Sussex Saved

The decline in UK chemistry departments has been staved off at least partially with a vote to save the department a Sussex University on the south coast that spawned two Nobel chemists.

According to The Guardian, ‘The University of Sussex has abandoned its controversial plans to axe its chemistry department following intense criticism from scientists across the country.’

Vice-chancellor, Alasdair Smith, originally suggested chemistry teaching be scrapped and a new bio-merged department take its place, but, the paper reports that an extraordinary university council meeting held on May 15 saw members adopting a recommendation that will see the incredibly well-respected department retained and expanded to include biochemistry.

Sussex has produced two Nobel chemists Sir John Cornforth (1975, for stereochemistry of enzyme-catalyzed reactions) and Sir Harry Kroto (1996 winner for fullerene co-discovery) with a former professor of physics, Anthony Legget, being awarded a share of the 2003 Nobel Prize for Physics, for his work at Sussex on the theory of superfluids.

Spectral Science News

The latest round up of science news from David Bradley goes live at spectroscopyNOW.com today.

Among May 15’s postings:

Biomedical researchers have long thought that male sex hormones play a critical role in controlling cholesterol levels and lipids and in the development of atherosclerosis, a serious risk factor for heart disease, but new research from Wyeth Laboratories reveals that a protein receptor in the body called FXR, could have a key role, as well as the receptor for the male hormone androgen. “Our results suggest that the activity of FXR must now be considered in studies on the roles of male sex hormones in cardiovascular disease,” Wyeth’s Mark Evans told me.

Also, Chinese scientists have developed a new cheminformatics method for analysing the products of chemical reactions without researchers having to worry too much about any impurities that might be present.

Third up on the spectrometer this week – Coating an alloy with a biocompatible material is a key step in making implants, such as replacement hip joints, that sit comfortably with the patient’s skeleton and undergo osseointegration. A relatively new technique known as surface sol-gel processing (SSP), which is related to the well-known bulk sol-gel technique, can be used to prepare bioreactive nanostructured titanium oxides for adding a thin layer of material on a prosthetic joint. Understanding how calcium is subsequently deposited and phosphate released will help in the fine-tuning of the preparation for the most effective osseointegration.

Finally, watch out for bent copper under stress. Bend a metal bar, if you’re strong enough, and depending on certain microscopic conditions the bar will yield to curvature or snap. Understanding what occurs at the microscopic level when metals are placed under stress has been a key aspect of materials science research for decades. Now, researchers in Denmark and the USA have used a new technique for tracking the orientational changes that occur within the grains of metal as it stretched. The research shows how the accumulation of defects actually strengthens metals during deformation.

There’s plenty more news from the rest of the team on spectroscopyNOW too…

Llama Caffeine Dip Test

After another sleepless night did you ever think that your so-called caffeine-free coffee may not be all it seems. But, how could you test to make sure the manufacturer’s claim of drug-free cafe latte is based on chemical fact?

Now, US scientists have developed a simple test for caffeine that could be incorporated into a portable device for use in the home to test caffeine levels in all kinds of beverages.

“We envisioned that a simple method to measure caffeine, even in hot beverages, such as coffee, would be of value to individuals and institutions wanting to verify the absence of caffeine,” says Jack Ladenson of Washington University School of Medicine in St. Louis, “This will greatly assist individuals who wish to avoid caffeine.”

Ladenson hopes to develop a simple caffeine test in which test strips that are treated with a specific antibody will react by changing color in the presence of caffeine.

The new test will be designed to be qualitative only: It allows a person to quickly determine whether caffeine is present, but does not indicate the exact amount or concentration of caffeine. In preliminary tests using coffee and cola, an experimental version of the test effectively distinguished caffeinated versions of these products from their decaf counterparts, Ladenson says.

Ladenson’s team hope to convert their antibody-based test for caffeine into a dipstick that could be sold in supermarkets although he confesses that he has no idea when such a kit will be available to consumers or how much it will cost.

Many of us like to avoid the late-night jitters and insomnia that follow a post-prandial espresso, but there are also concerns about the impact of chronic caffeine abuse on long-term health in terms of stress levels and blood pressures. The US Food and Drug Administration also warns pregnant women not to drink caffeine-containing beverages because of the risk of spontaneous miscarriage.

Ironically, the key to the caffeine test comes from llamas and camels – pack animals that have transported caffeinated commodities such as coffee, tea and cocoa for centuries. The immune system of camelids produces antibodies that are resistant to high temperatures common to a nice cup of char or coffee.

The researchers reasoned that if they could create heat-resistant camelid antibodies that reacted to caffeine, they could potentially build a durable assay suitable for use almost anywhere. The most stable version of a caffeine-specific antibody they produced came from a llama named Very Senorita, which worked even after being heated to 90 Celsius, about the temperature of a really hot cup of coffee. Similar antibodies from mice are destroyed at 70 degrees.

The researchers publish details of their test in the journal J Agric Food Chem in June.

For a cool coffee science experiment check out our education section.

Taxol to a T

Taxol is a natural product isolated from the Pacific Yew, Taxus brevifolia. The compound was isolated from the bark of that tree by Monroe Wall of the Research Triangle Institute in the 1960s. He and his colleagues were guided in their work by the discovery of in vitro activity against L1210 cancer cells.

As is customary, the individual who discovers a new natural product gets to name that compound. Wall thus naturally called this new anticancer agent taxol (tax from taxus, ol as in alcohol, small T). He used the name in his 1971 publication announcing the chemical structure.

After that, chemists working with the compound used this name, partly because its very complex structure virtually precluded using the systematic chemical name.

Probably because it was so hard to obtain it in quantity, the compound lay fallow on a shelf at NCI until the late 1980s. Interest was revived when Susan Howrwitz discovered that the drug acted by a previously unknown mechanism: in essence it freezes cell division mid-stream by stabilizing the microtubules that should wither after pulling appart the pieces of the cells-to-be. The late Matt Suffness at NCI then made a concerted effort to pursue the compound. As part of this, NCI apparently requested bids from the private sector to join in developing taxol as an antitumour drug. This was to be one of the first such joint efforts known by the acronym CRADA (Cooperative Research And Development Agreement). The proposal tendered by Bristol Myers was deemed to be superior to the others leading to the company being awarded the agreement. The rest as they say, is history.

Somewhere along the line, however, someone either forgot to register the name taxol with the USAN as the non-proprietary name for that substance or may simply have been unaware of this requiremnent. This left the door open for Bristol Meyers to acquire Taxol as a trade name allegedly via the purchase of the TradeMark of an old laxative product and to have the non-proprietary name paclitaxel accepted as the generic term of Taxol. This meant that chemists would no longer be allowed to talk of taxol generically but would have to refer to paclitaxel, unless they were talking about BM’s drug in which case that would be Taxol, with a capital T.

So what of this laxative? It was apparently produced by Continental Laboratories Ltd of London in tablet form for the physiological treatment of constipation.

Pastel Chef and Chemist

In this week’s Alchemist I vaingloriously pronounced that oncologists might soon be able to image tumours as quickly and easily as radiologists view broken bones with X-rays.

Sciencebase contributor Dan Lednicer, a retired organic chemist turned pastel chef emailed me to point out that the statement regarding the power of X-rays required qualification:

“One day this last February, I happened to fall on my side in a parking lot. The persistent pain led me to get an X-ray the next day. This showed nothing out of the ordinary. When getting dressed one morning a week later, I found that any weight on my left leg led to excruciating pain. An X-ray in the emergency room at the hospital still showed nothing. It took an MRI (I almost wrote NMR!) to show a clean brake high up on the femur.

I now sport an impressive metal rod with a couple of appurtenances down the middle of that femur. This sails through metal detectors like a breeze, as it is made of titanium.”

So, it seems. X-rays are not the gods of imaging that my flippant remark would suggest. As to why titanium does not show up on airport metal detectors would make an interesting assignment for science class. Feel free to post your thoughts…

Properties and Uses of beta-alanine

“What are the properties and uses of beta-alanine?”

beta-Analine is an amino acid formed metabolically from dihydrouracil and carnosine and used as one of the building blocks of proteins. Researchers have demonstrated neuronal uptake and neuronal receptor sensitivity to beta-alanine and so it has been labelled as a false transmitter replacing gamma-aminobutyric acid. As such, it is finding application as a GABA uptake inhibitor in treating a variety of disorders in which tremor is a serious symptom.

Benzene Soft Drinks Redux

One further thought on the benzene soft drinks story following on from sciencebase reader Ross Getman’s comment…

Bob Buntrock (of Louisiana State University) on the CHMINF-L discussion group mentions the recent C+EN article on this issue, (Dispute Over Benzene In Drinks, Bette Hileman, Chemical and Engineering News, 84(17), April 24, 2006).

Buntrock points out that when tests were carried out again in 2005, they revealed a very different picture of benzene levels than before. Apparently, previous tests by the FDA showed that almost four out of five beverages tested, even after “reformulation”, had benzene levels greater than 5 ppb, the US standard for tap water. The latest (preliminary) tests showed no benzene or levels less than 5 ppb.

“Since the first method involved heating samples at 100 Celsius for 30 minutes(!) [His exclamation] and the latest method uses headspace methodology “which does not involve much heat”, guess which method would appear to be more accurate,” says Buntrock. In his opinion, “considerably more decarboxylation of many acids or carboxylates will occur under the previous drastic conditions, which are extremely unlikely to occur under normal usage of soft drinks.”

Jacob Zabicky of Ben Gurion University, Israel, followed up Buntrock’s comment with a remark based on knowledge of the physical properties of benzene. “My gut feeling based on the relative solubility of benzene in water and its volatility from solution at ppb levels,” he said, “is that if there is any ppb level benzene at the start it will go with the fizz.” On the basis of the Henry Constant of benzene in water, Zabicky adds that, “The given value means that for every four molecules dissolved in a given volume of water one molecule of benzene is found in the same volume of headspace in equilibrium.” In other words if the headspace volume is large (i.e. the air above a drinks can as it is opened) compared to the volume of soft drink, then the benzene will be strongly depleted from it.

Disease Mongering

I was a bit tardy covering the recent conference on disease mongering, but to make up for it have posted a new poll on the SciScoop site to give visitors a chance to voice their opinion.

A conference held April 11-13, in Newcastle, Australia, raised some serious questions about the motives of the pharmaceutical industry. The patents on drugs for old-fashioned diseases that were originally making a $1billion a year are almost all expired and new avenues of research under the umbrella of biotech have yet to make the same level of return for other diseases. As such, there is a feeling among some observers that “new” conditions, such as restless legs syndrome, attention deficit hyperactivity disorder (ADHD), and sexual dysfunction are being hyped by the industry as the serious ills of our time that need new (lucrative) treatments. Is this the case or can we simply not do without the chemical fix of those repeat prescriptions? A collection of freely accessible essays on the subject of disease mongering is available on the PLOS Medicine site.

Visit SciScoop to vote in the poll and help us answer the question – “Are we drug company puppets?”

Periodic Table History

UPDATE: June 2011 – debate is raging as to what format the Periodic Table should ultimately take and indeed whether there is an ultimate, fundamental structure or whether it is merely a convenience. Check out the periodic table debate here.

Here’s a book no chemist, or indeed no scientist, should miss – The Periodic Table: Its Story and Its Significance, by UCLA chemical philosopher Eric Scerri. Older readers will recall my Alchemist interview with Eric Scerri.

The book has already had some excellent advance reviews, one in particular from my good friend John Emsley, of Cambridge U says: “Written to a high standard of scholarship, ‘The Periodic Table’ is the only book of its kind currently on the market, giving both an historical and philosophical perspective to the development of this key to the elements. The philosophical discussion Scerri weaves through its pages is rarely found in chemistry books, giving it a special quality that will appeal to the scientific community at large. In years to come it will be seen as essential reading for all who aspire to lecture and write on the subject.”

Peter Atkins, who I have never met admittedly, had this to say: “Few concepts are more important in chemistry than the periodic table, and Eric Scerri’s book offers a wonderfully thorough, lucid, and provocative introduction for both chemists and the scientifically literate to this major cultural contribution. Anyone interested in the foundations of chemistry will take delight, inspiration, and information from this highly approachable book.”

You can place an advance order via amazon, the book hits the shelves September 15 at $35 hardcover.

The Periodic Table

Science News with a Spectral Twist

Channelling toxins Novel treatments for high blood pressure and other disorders could emerge from high-resolution solid-state NMR studies that reveal how toxins affect the structure of potasssium channels in the cell.

Marc Baldus of the Max Planck Institute for Biophysical Chemistry in GÃ¶ttingen and colleagues in France and Germany have exploited a special protein synthesis procedure to follow how potassium channels and toxins combine to change the structure of the channel.

Zeolites step-by-step The evolution of zeolites has been followed by University of Minnesota chemical engineer Michael Tsapatsis and colleagues using microscopy and X-ray diffraction. Their study could lead to a new approach to designing and synthesizing novel variations on the zeolite theme for use as molecular sieves, catalysts, and sensors.

Analytical raft floats organic NLOs A combination of analytical techniques has proved its worth in assessing a series of non-linear optical materials for use in future organic optoelectronics devices. Juan LÃ³pez Navarrete of the University of Malaga, Spain, and colleagues at the University of Zaragoza-CSIC and the University of Minnesota, Morris, USA, used UV-vis, IR, and Raman spectroscopy, nonlinear optical (NLO) measurements, X-ray diffraction, and cyclic voltammetry to assess the properties of a series of tricyanovinyl (TCV)-substituted oligothiophenes.

A particularly golden study US researchers have devised what they describe as a very efficient method for making well-defined gold nanoparticles with equal numbers of hydrophobic and hydrophilic arms. The V-shaped arms are alternately distributed across the surface of 2 nanometre gold core particles. The solubility of these nanoparticles in a wide range of solvents means that they should be amenable to further processing with various chemical modifiers. Such nanoparticles have potential in optoelectronics, catalysis, and biomedical applications.