Lakes at last   

Titan, Saturn's largest moon, is scattered with lakes, an international team of researchers confirmed in Nature. Their definitive evidence came from radar images taken by the Cassini spacecraft in July 2006, on its 17th Titan flyby, showing dark lake-like patches up to 70km across in the moon's northern hemisphere. The lakes look very like those on Earth but are composed of methane and ethane, not water, as Titan's surface reaches a chilly -179 °C.  

A further 22 spacecraft flybys scheduled up to 2008 should uncover further details of methane's circulation around Saturn's moon; perhaps analogous to Earth's water cycle. Cassini's 

Saturn tour may yet be extended to 2010. 

Aspirin spat 

Chemists have proposed a second crystal packing form (polymorph) for the household drug aspirin, arguing that shoddy data interpretation had marred a 2005 second polymorph suggestion.  

The new aspirin polymorph could only be obtained coexisting with aspirin's well-established packing form, calling into question what can be considered a polymorph, said co-author Gautam Desiraju, publishing in Angewandte Chemie. 

Each polymorph of a compound is viewed as a separate patentable substance by law, so the research might have more than academic implications. 

Nanodiamonds not toxic 

Research published in The Journal of Physical Chemistry B  reassures those worrying about the possible dangers of diamond nanoparticles, which have been suggested for use in humans as drug carriers, imaging probes, and implant coatings.  

Scientists tested nanodiamonds ranging from 2 to 10 nm, and found they were not toxic to a variety of different cell types, which grew on nanodiamond coated substrates without apparently changing shape or internal function. 

POP plan published 

The UK government has published a consultation paper outlining how the country will meet the Stockholm convention on persistent organic pollutants (POPs) - a group of toxic, bioaccumulative chemicals including pesticides, dioxins and furans.  

Nearly all of these chemicals have been banned in the UK for several years; the levels of dioxins, however, produced as a byproduct of industrial processes and combustion, still need to be controlled. A dioxins action plan explains how the UK plans to continue reducing its emissions. The closing date for responses is 19 March 2007.

The secret life of comets 

Comets may have delivered the complex organic molecules required for life to Earth, researchers publishing in Science  suggested after finding organic molecules in grain samples collected from the comet Wild 2 during Nasa's seven-year 'Stardust' mission. 

The comet also contained calcium silicate minerals that form only at high temperatures: implying those materials were first melted near the Sun, then ejected further away. This surprised astronomers who thought comets formed only in cold, remote parts of the solar system. 

Leaks and fires 

German chemical company BASF is investigating a toxic leak which injured 37 people working on the company's UK site in Seal Sands, Teesside. 

Two employees taken to hospital are recovering after the incident on 4 January. The chemical involved, hexamethylenediamine (HMDA), is used to manufacture nylon fibres and plastics. 

In Louisville, Kentucky, US, train cars carrying cyclohexane, methyl ethyl ketone, butadiene and ethanol derailed and exploded on 17 January, with no serious injuries reported. The accident followed a 15 January butyl acetate spill in central Kentucky, after runaway rail cars struck two parked vehicles. 

Chinese media agencies reported on 17 January that a chemical plant explosion in Kuanshan, Jiangsu province (neighbouring to Shanghai), killed seven people.  

Superheavy magic 

German researchers have created an unusually stable isotope of the superheavy element hassium, with an approximate half-lifeof 22 seconds. Hassium-270 was created by smashing magnesium ions into a curium target.  

The isotope has 108 protons and 162 neutrons, both so-called 'magic' numbers because the particles exactly fill nuclear shells, analogous to filled electron shells in a noble gas. This doubly magic combination explains why the isotope is so relatively long-lived. 

Tricks of the light 

A combined German/US team, publishing in Optics Letters, has become the first to create a metamaterial with a negative refractive index for visible light. The material, a mesh of layered silver and magnesium fluoride, operates in the red end of the visible spectrum. Such materials could be used in new kinds of lenses or invisibility cloaks (see Chemistry World, December 2006, p7). 

Another Optics Letters  paper has reported a breakthrough in the efficiency of light-bending organic molecules. According to research leader Mark Kuzyk, the molecules, which could be used for optical switches, were markedly better at absorbing or refracting light because electrons were forced to bump across, rather than flow smoothly, from donor to acceptor ends. 

Molecular Solomon's knot 

A ornamental link pattern known as 'King Solomon's knot', found in the crowns of African kings, in the walls of Italian abbeys, and in Celtic stained glass windows, has been created in molecular form.  

The knot's synthesis, published in Angewandte Chemie, has been achieved before, but not by the self-assembly of twelve individual components, their threading directed by metal templates. A dynamic equilibrium between various possible molecular knot products is resolved upon crystallisation, reported a US team led by Fraser Stoddart. See news article Knighthood for services to chemistry.

Carry on carbon cuts 

The European Commission announced a new low-carbon energy plan on 10 January. If adopted at a March summit, the plan will require member states to reduce greenhouse gas emissions to 20 per cent below 1990 levels by 2020. Commissioners said they would push for a 30 per cent cut in future international negotiations. By contrast, the UN's Kyoto Protocol asks parties to return their emissions to five per cent below 1990 levels by 2012. 

On 12 January, US presidential election candidates John McCain (Republican) and Barack Obama (Democrat), together with independent senator Joe Lieberman, re-introduced a climate bill to Congress, asking for caps on greenhouse gas emissions from industry. The legislation requires that US emissions be cut back by two per cent a year, therefore dropping to 1990 levels by 2020, the senators said. Under another proposal, by senator Jeff Bingaman, the Democrat chairman of the Energy and Natural Resources committee, annual emissions would increase until 2030 before declining. 

Cold trap

Physicists have cooled large organic molecules to less than 0.1K, using a technique, 'sympathetic cooling', that could also work with proteins.  

Researchers reporting in Physical Review Letters  trapped a charged dye in electromagnetic fields, reducing its temperature by transferring heat to more easily laser-cooled barium atoms.  

Cold molecules can stay trapped for hours or days, allowing researchers to study processes that work on slow time scales, like some electronic transitions.  

Blood prions filtered 

US researchers have developed a way of filtering blood to remove prions, the mis-formed proteins which can cause variant Creutzfeldt-Jakob disease (vCJD). The technique, reported in The Lancet, was tested in hamster blood spiked with prions that cause scrapie (related to vCJD). It could reduce the risk of prion infection during blood transfusions, though is yet to be proved effective in humans. 

Chemical security tightened 

US legislators have proposed a host of security guidelines for chemical plants and transportation. The Department of homeland security (DHS) is inviting comment until 7 February on its regulations requiring companies to assess their plants' vulnerability to terrorist attack.  

The Transportation security administration (TSA) wants better protection for chemicals transported in rail cars, asking for tracking systems and improved car monitoring; the public have 60 days to comment after the proposals were published on 
21 December. 

The Australian government has released a discussion paper identifying 95 chemicals that may need tighter security. The paper, proposing a range of control measures, is available for public comment until March. 

Toxics reporting eased  

New Environmental protection agency Toxics Release Inventory (TRI) laws mean US industrial facilities will file less information about chemicals released in small quantities. 'Small' has been defined as below 2000 lb a year, increased from a previous 500 lb. The policy is intended to encourage companies slightly over the limit to release smaller quantities of hazardous chemicals, benefiting from less bureaucracy. 

But environmental groups say the measure means the public is being denied information about toxic chemical threats. TRI legislators have already backtracked on proposals to reduce the burden of reporting to every other year, rather than annually.