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Category Archives: Chemistry

Chemistry in its element – theobromine

This week’s Chemistry in its element podcast is a must for all chocolate lovers as Brian Clegg gives us a taste of theobromine: the food of the gods that’s bad news for dogs.


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The science behind Marks & Spencer’s fruit packaging

Red strawberry

Ground breaking packaging news has reached CW Towers, British retailer Marks & Spencer is launching new packaging to extend the life of strawberries. The store, whose food adverts have become much copied in recent years, say their new packaging will extend the life of fruit stored in the fridge by up to two days. So these are not just any berries, these are M&S berries, but why?

The packaging apparently uses a 8cm x 4.5cm strip that contains ‘a patented mixture of clay and other minerals that absorb ethylene‘. Ethylene, or as we chemists tend to refer to it, ethene, is the smallest possible alkene and a well known plant hormone involved in the ripening of fruit. It’s why the trick of putting a ripe banana in a bag with unripe fruit will ripen it. I haven’t found the patent from the firm involved, but we can make some educated guesses about how this works. Clay is an aluminosilicate with a large volume, so perhaps what we’re talking about something akin to a zeolite, with a large surface area for the gaseous ethene to adsorb onto. And as for the other minerals, perhaps the pores are impregnated with some antibacterial agent, like silver, to keep the fruit extra fresh. That’d be my guess.

But I can’t help thinking this is of more use to the store itself, for preventing fruit spoilage on the shelves. I certainly don’t tend to take strawberries home and stick them in the fridge, I wash them and put them in the fruit bowl, or just eat them all at once and I doubt I’m the only one. But maybe I am, would this help you?

If you want to read more about how chemistry is being used in packaging, check out this feature that Nina wrote in 2009, as well as searching for more recent news articles.

Laura Howes


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Will Sheri Sangji’s death change safety culture?

Sheri Sangji

Sheri Sangji (Courtesy of Naveen Sangji)

Developments in the case of Sheharbano (Sheri) Sangji’s death at UCLA in 2009 have been dominating the chemistry news for the last week or so. With the University of California and Sangji’s supervisor Patrick Harran facing criminal charges relating to their management of their health and safety obligations.

The detailed twists and turns of the case have been doggedly covered by Jyllian Kemsley over at Chemical & Engineering News, and debate online over where responsibility lies and what the problems were has been voracious.

Sangji’s is the most serious of a series of high-profile incidents, including explosions at the University of Liverpool, UK, and one at Texas Tech University, US, where a student lost three fingers and perforated an eye among a list of other injuries. This prompted the US Chemical Safety Board to investigate the incident and their report paints a stark picture of safety at TTU (which by all accounts has improved significantly since). The case study also includes anecdotal evidence from 120 other incidents, suggesting a more widespread issue.

Here at Chemistry World, we wanted to examine what it takes to make laboratory environments safer, and what differences there are between the US and the UK and elsewhere.  You can read my story here, but we wanted to take the opportunity to ask you, our readers, what you think:

What is the safety culture like in your institution, or others you’ve worked in?

Has anything changed since these incidents? Do you think it will?

Having spent a few years in a synthetic chemistry lab myself, as well as stints in industry, I’ve come across my fair share of minor incidents, both at my own bench and at colleagues’. I also saw the difference between attitudes to safety at two UK universities. Personally, I hope that our laboratories can become safer places to work, but there are not going to be any quick fixes. We all need to take responsibility for safety – after all, understanding safety comes down to understanding chemistry. If you know the risks involved with what you’re doing, you can take steps to manage them, just like when you drive a car or cross a road.

One of the clearest messages that came back to me from talking to several health and safety professionals in researching my story was that no one wants to stop anyone doing research. If it’s done right, health and safety management should enable researchers to do the work they need to, but in an appropriate environment. So again, let us know what you think – does this happen where you are?

Phillip Broadwith

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Mr. Lee – Chemistry rap – Video

21-01-2011 21:48 A song about the basics of chemistry for my eighth graders, sung to the tune of "Fire Flame" by Birdman ft.

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Mr. Lee - Chemistry rap - Video

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One (nano) ring to rule them all

OK, it’s not quite forged in Mount Doom but this tiny ring caught my eye today. A full 22nm in diameter, it’s made using a tobacco mosaic virus coat protein as a template. The ring self assembles from solution, with 10 nanoparticles interacting with arginine residues on the outside edge of the protein. Each nanoparticle is between 3.5 and 5nm in diamter, which equates (if I’m still able to do basic maths correctly) to around 6 x 10-19g of gold, or, at today’s prices, £2.17 x 10-17, possibly the cheapest bit of jewellery ever!

Nanoring

Or perhaps not, as I imagine the manufacturing costs and overheads are a bit higher than an ordinary jeweller’s.

So why bother? Well gold rings of this size are predicted to have interesting optical properties, and perhaps even have negative optical permeability or refractive index, which could have amazing applications. But how do you know if you can’t make them? And make them easily.

In the meantime, we in the office will just keep making bad Lord of the Rings based puns.

The research is published in Nano Letters, DOI: 10.1021/nl203368v.

Laura Howes

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Chemistry in its element – neuraminic acid

The flu season is soon to be at its peak, but just how does the flu get into you? In this week’s Chemistry in its element podcast, Josh Howgego tells the sugar-coated tale of neuraminic acid and the role it has to play in the fight against flu.


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