May 2006 – David Bradley

Totally tubular peptide rings

The highly unique crystal structure of nanotubes constructed from cyclic peptides is revealed this month by Japanese researchers in the journal Organic Biomolecular Chemistry. The descendents of these novel nanotubes could find a role in future molecular electronic devices, according to the team, who allude to the high macrodipole moment of their materials.

Shunsaku Kimura and colleagues at Kyoto University, have built on the work of ETH’s Dieter Seebach and Wisconsin’s Sam Gellman to use supramolecular chemistry to construct through self-assembly a stacked column of cyclic peptides, themselves made from three ACHC amino acids linked in a ring. ACHC is the trans-2-aminocyclohexylcarboxylic acid. The team used Fourier transform infra-red and nuclear magnetic resonance spectroscopy measurements and computational calculations to demonstrate that this cyclic tri-beta-peptide has C3-symmetry with the amide groups in the trans positions.

To read my full article visit the spectroscopyNOW.com crystallography channel.

Solvent solution

Interest in alternative solvents to replace volatile organic compounds is on the increase, so improved understanding of the properties of these alternatives is needed. One class of solvents researchers are keen to learn more about are the room temperature ionic liquids (RTILs). Researchers have commonly used absorption or fluorescence to study solvation properties. But now scientists in Japan, have carried out a Raman spectroscopic study of a series of RTILs using diphenylcyclopropenone (DPCP) and phenol blue (PB) as probes to reveal information about solvent acceptor numbers. Their results could have implications for the use of these “green” solvents.

Find out more in my latest news write-up on SpectroscopyNOW (Raman channel)

Cesamet, THC and chemotherapy

The drug Cesamet (nabilone), a derivative of tetrahydrocannabinol, was “re-approved” for the clinical market this week for use in treating the side-effects of cancer chemotherapy, including nausea and vomiting. Genetic Engineering News reports that Valeant Pharmaceuticals International (NYSE:VRX) announced that the US Food and Drug Administration (FDA) has given marketing approval for Cesamet (CII) (nabilone) oral capsules. The drug interacts with the CB1 cannabinoid receptor found throughout the nervous system, its interaction with this receptor calms nausea and stifles the vomiting reflex something that many chemo patients would welcome.

What is particularly intriguing though is that this drug made a brief appearance on the pharma market in the 1980s before being pulled. Why? You may well ask. Perhaps attitudes to marijuana were less liberal than today leading ethical committees to feel that derivatives of their active ingredient are acceptable whereas during 1980s they were not. Or, perhaps it is simply that other anti-emetics on the market were at the time more successful with most patients and did not have the negative connotations of illicit drug use associated with them. Now, more than twenty years later those anti-emetics are off-patent and only making generics manufacturers a profit. The time was thus ripe for a new drug to take their place. I could be wrong, Cesamet’s patent was approved on Boxing Day 1985 so it too may have only a short shelf life.

Any Sciencebase readers with insider info on this are welcome to add a comment to this post.

Meanwhile you can subscribe to the print edition of Genetic Engineering News for free here.

Bubbly extractions

Air-assisted solvent extraction (AASX) process is an important new technique for the extraction of valuable metals such as copper, nickel, cobalt and uranium, as well as wastewater treatment where metal concentrations are typically low.

Now, a Canadian research team has discovered that it is the bubbles that play a critical role in providing a high solvent-specific surface area and ease of phase separation. Now, the team has used layer interferometry (in the UV-vis region) to measure the time-dependent thickness of a film formed by blowing an air bubble in kerosene-based solvents. They used Fourier transform infra-red spectroscopy to determine its chemical composition.

Read more in my news article on the IR channel on spectroscopyNOW.com

Hangover Culprit Found

Hangover culprit

A fellow “Digger” dugg this article I posted on Reactive Reports issue 47 in which I discussed: Hangover Culprit Found. Of course, the headline was slightly misleading as was the opening paragraph which alluded to acetaldehyde being the cause of hangovers. This was pointed out to me by no less than a few of the other 470+ Digg members who voted the article to the front page of that site.

Of course, it is well known that acetaldehyde (ethanal) is an ethanol metabolite (made when the liver goes from Oooooh, to Aaaaah) and is itself toxic and considered to be one of the leading causes of those awful morning after symptoms. However, the actual research I discussed focused on specific aspects of the genetics of some East Asians who suffer particularly bad hangovers. You can read all about it in Issue 47 of Reactive Reports.

Understanding soil pollution

A lack of understanding of how problematic contaminants, such as polycyclic aromatic hydrocarbons (PAHs), pesticides, and herbicides interact with soil organic matter (SOM) is an issue that can hinder remediation of polluted sites, muddy the waters when it comes to determining the ultimate fate of pollutants, and reduce the viability of risk assessment models when considering new uses for brownfield and old industrial sites. Fortunately, Canadian scientists have now suggested that a range of techniques, including NMR and mass spectrometry, could clarify the various underlying mechanisms.

According to Myrna Simpson of the University of Toronto, Canada, a combination of conventional methods, such as equilibrium sorption and isotherm modelling, with NMR characterization of organic matter in soil, could help researchers get to the root of the problem.

Dig in at SpectroscopyNOW.com to read my complete article.

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Lighting up the near infra red

A novel class of lanthanide compounds that emit in the near-infra-red could open up new possibilities for the use of NIR in biological imaging as well as leading to materials for optical amplifiers and light-emitting diodes (LEDs) operating at telecommunications frequencies.

According to Jean-Claude BÃ¼nzli of the EPFL, the Federal Polytechnic School in Lausanne, Switzerland, lanthanide compounds are of great interest in a number of fields because they produce narrow and easily recognisable emission lines in the NIR, they also have relatively long excited state lifetimes relative to organic chromophores. It is this latter characteristic of lanthanide coordination polymers that makes them of particular interest as they can be applied to time-resolved spectroscopy in analytical procedures allowing an enhanced signal-to-noise ratio and so much-improved sensitivity for luminescent analyses and imaging.

Follow my full write-up in the IR channel on SpectroscopyNOW.com.

Nanotechnology and medicine

X-ray imaging is a very mature, although not infallible, field of medicine, but it does not lend itself to the detection of small tumours or their metastases. Now, Sangeeta Bhatia in Boston, Massachusetts and colleagues at the Harvard-MIT Division of Health Sciences and Technology hope to remedy that by using iron oxide nanoparticles to allow MRI to visualize areas of tumor invasion.

The key to their novel imaging agent is a tumour-specific protease, which is found, as the name would suggest, primarily in and around tumour cells. Bhatia and her team engineered a method by which iron(III) oxide nanoparticles could form aggregate clusters under physiological conditions.

Find out more about how Bhatia and her colleagues hope to exploit nanotechnology to improve medicine in my current news round-up on SpectroscopyNOW.com

Get Your Eyes Tested Ref!

What did I tell you? The floodgates are opening to football (or soccer) related press releases with a scientific twist. The other day it was the Institute of Physics playing keepy-uppy with the physics of football, today it’s the turn of London’s Science Museum (sorry that should be science museum, per their logo.

According to their news release, new data released today [Into the wild, is that?], proves something that all football fans already know – the mood of the crowd can alter the referee’s decision.

Former international referee, David Elleray, will attempt to send off this idea at a debate on the science and psychology of football at the Dana Centre in London. 98% of fans questioned think that referees are influenced by crowds. The national survey of 2,517 football fans was conducted by The Football Fans Census on behalf of the Dana Centre. The results tally closely with research conducted by Alan Nevill of the University of Wolverhampton, whose studies of football crowds and referees show that home advantage is huge and that referees are affected by their environment.

The research could have enormous implications for a possible Germany v England clash in this year’s World Cup, says the press release in a serious attempt to get onside with the tabloid press…

Nevill’s study showed that crowd noise influenced referees’ decisions to favour the home team. It was suggested that whenever a home player commits a foul, the crowd’s reaction is capable of activating the ‘potent stressor’ that might increase the level of uncertainty or indecision of the referees. The research indicated that the home team was penalised approximately 16% less than when compared with no noise condition.