In my imagination, conferences in the past involved a passionate speaker (usually wearing a hat) who was disclosing his/her latest discoveries, vehemently speaking or writing on a blackboard (sometimes performing live experiments) while the audience was listening in a profound, respectful silence.

Today, what I saw was somewhat different – and I’m not talking of speakers not wearing hats. Actually, I was at a presentation seating next to a professor, who was preparing the powerpoint he was going to present in the afternoon. To do this, he had to ask his collaborator, seated next to him, about the meaning of some graphs he intended to include in the presentation. This took approximately one hour, and was quite disturbing to all the people around, since the discussion included mumblings and laughters.

So, without even considering half of the members of the audience who checked their e-mails or the news on CNN every 5 minutes on their iPhone, I was wondering whether the speaker was noticing this lack of attention. The answer I guessed is probably no (because speakers are generally too busy and stressed to notice what happens behind the front row) but still, I’m wondering why people go to talks to prepare their own slides??

Besides, I wanted to mention today’s plenary session, where Prof. Michael Grätzel from EPFL (it’s always funny to go abroad to attend talks from our own faculty) presented the latest advances in dye sensitized solar cells (DSCs). I still hope to write a full post about Prof. Grätzel’s work sometimes (like next October 6th), and here I just want to mention that there is now a Michael Grätzel Center in Wuhan (China) which, I think, is quite something. The optimism and enthusiasm of Prof. Grätzel are always extraordinarily communicative (especially when it comes to recent applications), and I’m deeply convinced that the future is bright for dye-sensitized solar cells

Today was the opening day, and thousands (really!) of chemists gathered in the huge congress center. The first -and only- talk I attended (due to a somewhat late arrival) was given by Prof. Klaus Müllen (from the Max Planck Institute for Polymer Research in Mainz). He quite impressively demonstrated how perfect graphene ribbons can be generated by bottom-up synthesis and subsequent reactions of benzene dendrimers (contrary to the method involving the peeling of graphite with tape). A very motivated and passionate speaker, he captivated his audience by showing amazing results, obtained by a careful design of a ‘core’ molecule, followed by its self-assembly into more complex structures.

This lecture was definitely a good start, and I’m looking forward to the next ones.

For more details:

Nature 2010, 466, 470-473 doi: 10.1038/nature09211

Advanced Materials, 2010. doi: 10.1002/adma.201001275

*I had to deal with my thesis writing & exam and some funding application stuff recently… and was close to an overdose of chemistry, hence my absence from the web.

Cloud whitening (SRM)

This concept, imagined by Stephan Salter from the University of Edinburgh, consists in spraying seawater in the atmosphere to increase reflectiveness of clouds. The clouds, produced by a fleet of around 1500 unmanned ships, would reflect more radiation from the earth. However, such an operation could have unexpected -and difficult to modelize- effects on oceanic climates and streams.

Covering the deserts with white films (SRM)

According to Alvia Gaskill who proposed this solution, covering a large enough area of the earth (first candidates would be Sahara, arabic and gobi deserts) could be expected to offset some or all of the projected additional radiative forcing and global warming from 2010 to 2070. Together with tremendous costs, ecological consequences such as perturbation of the atmospheric circulation (which could result in sub-saharian monsoon perturbation) must be feared.

Space sunshade (SRM)

Basically, this concept proposed by Roger Angel (University of Arizona), involves the use of trillions of small umbrellas, that would be put in orbit an stop some sunlight from reaching the Earth. If small 1 gram, 60 cm diameter discs were used, 800 000 of them would have to be sent every… minute, for 30 … years, in order to decrease the radiation hitting our planet of 1.8%.

Stratospheric sulfate aerosols (SRM)

Inspired by the eruption of Mount Pinatubo in 1991, which projected tons of particles in the atmosphere, and noticeably cooled the global temperatures of 0.5°C, chemistry Nobel Prize 1995 Paul J. Crutzen suggested the injection of sulfur compounds in the atmosphere. But this project could perturbate water cycles, the stratospheric ozone chemistry and biological life, which make large scale experimentation somewhat unrealistic.

Ocean iron fertilization (CDR)

This method involves the seeding of ocean with iron in order to promote a phytoplankton bloom, which can remove carbon dioxide from the atmosphere. Again, several side-effects are to be expected, as well as an increased water acidification, and the creation of large zones depleted from oxygen (the more the algae ‘breath’, the less oxygen available for the other species).

Although geoengineering is a flourishing field (just try to enter it in wikipedia), many of its promises will probably come true too late (if at all) if one wants to reduce anthropogenic global warming and climate change… scientific creativity will have to find other ways to deal with climate modifications.

The team from University of California (UC) Berkeley, and the Lawrence Berkeley National Laboratory, led by Carolyn Bertozzi, adapted the methodology known as ‘click-chemistry‘ to the particular conditions required by ‘in vivo’ conditions. Indeed, the original ‘click’ procedures, developed by Barry Sharpless (2), involved the use of toxic copper catalysts. In their article, the authors use a copper-free click reaction to label glycans – sugars particularly abundant on the surface of cells, where they are active in cell activity signalling, as well as in response to infections – which are thought of as appealing target for molecular imaging inside living organisms.

The first step involved the injection of azide-containing sugar derivatives, which are known to metabolically label glycans with the azide function. Then, a purposedly designed molecule carrying a signalling unit as well as a function reactive towards azides, had to be injected. The click reaction proceeded and as a result, glycans could be labeled in vivo, which paves the way for future specific biomolecule labeling inside living organisms.

Click chemistry inside a mouse (reproduced from ref. 1)

References:
(1) Pamela V. Chang, Jennifer A. Prescher, Ellen M. Sletten, Jeremy M. Baskin, Isaac A. Miller, Nicholas J. Agard,
Anderson Lo, and Carolyn R. Bertozzi, “Copper-free click chemistry in living animals”, Proc. Natl. Acad. Sci. USA, published online before print January 14, 2010. doi:10.1073/pnas.0911116107

(2) H. C. Kolb, M. G. Finn and K. B. Sharpless “Click Chemistry: Diverse Chemical Function from a Few Good Reactions”, Angew. Chem., Int. Ed. 2001, 40 2004–2021. doi:10.1002/1521-3773(20010601)40:11<2004::AID-ANIE2004>3.0.CO;2-5

Antonio Stradivari. Source: What We Hear in Music, Anne S. Faulkner, Victor Talking Machine Co., 1913.

A team led by Jean-Philippe Echard from the Laboratoire de recherche et restauration in the Musée de la Musique in Paris (an institution rarely found to contribute to Angewandte papers) recently published a study where investigations performed on 5 instruments that span 30 years of Stradivari’s career, are reported. They used complimentary analytical techniques to investigate the different varnish layers. To make the long story short, they found … nothing unusual or unexpected, but only materials broadly used in this time. The varnish is essentially made of two layers, the first (lower) one being used primarily to seal the wood and made of classical siccative oil. The second (upper) layer was found to caontain the same oil mixed with organic resins, and pigment particles. The latter were identified, and again, were found to belong to broadly used materials: inorganic salts (iron oxides, mercury sulfide) or organic crimson pigments.

Spanish Stradivarius II of c. 1687, on exhibit at Palacio Real de Madrid. Author H. Svensson

In conclusion, no trace of long hypothesized gums, amber or protein was found in any of the five instruments that have been investigated. Only common materials were used, and one must admit that the extraordinary quality of his instruments was (and still is) due to Stradivari’s exceptional talent as an intrument builder, but not to supernatural trick he may have used!

Reference: J.-P.Echard, L. Bertrand, A. von Bohlen, A.-S. Le Hô, C. Paris, L. Bellot-Gurlet, B. Soulier, A. Lattuati-Derieux, S. Thao, L. Robinet, B. Lavédrine, S. Vaiedelich, Angew. Chem., Int. Ed. published online. DOI: 10.1002/anie.200905131

It is well known that the ‘usual’ green colour is due to the presence of chlorophyll in the leaves, which harvest red and blue light to fuel photosynthetic reactions. In turn, photosynthesis allows the plant to produce carbohydrates (sugars) to sustain growth and development, together with converting carbon dioxide into oxygen. When temperatures start to decrease, and days to shorten, the amount of chlorophyll in the leaves slowly decays. Indeed, warm temperatures are required for the plant to replace the chlorophyll which is gradually decomposed over time. As the concentration of chlorophyll decreases, other dye molecules present in the leaves become more and more visible. These are essentially carotene (which gives carrots their colour) and anthocyanins (present in red grapes and wine). Depending on the tree, and on the weather conditions, the leaves become yellow or more red-brown as the green colour fades, giving rise to awesome landscapes. I spent some holiday in Japan just one year ago, and the weather forecast during this period includes very detailed maps showing the ‘red leaves forecast’!

Autumn colors in Japan, here in Shirakawa-go....

... and in Nikko.

And here are some of the molecules responsible for these various and impressive color changes:

In this context, lots of effort is dedicated to find ways to detect and destroy such compounds before they can cause harm. An appealing solution was recently proposed by a research team led by Julius Rebek, Jr. at the Scripps Institute. In an article recently published in Angewandte, they show how their novel molecules can signal the presence of organophosphorus compounds, but also render them harmless by undergoing a rapid reaction.

The sensing systems is based on an aromatic ring equipped with an oxime group (C=N-OH), which is known to react with organophosphorus compounds. The intermediate product instantaneously reacts further (which is important since at this point, the toxicity survives) to form a harmless decomposition compound and a fluorescent unit, which is used to signal the fact that the reaction has occured, and therefore the presence of toxic chemicals! Really smart approach!

References:
T. J. Dale, J. Rebek, Jr. Angew. Chem., Int. Ed. 2009, 48, 7850 –7852. DOI: 10.1002/anie.200902820

Press release: Ring Closure as Warning

Of course, I am not critisizing the recipients‘ work (anyway, I couldn’t since I am a chemist and don’t know lots of things about ribosomes, apart from their double-potato shape they always have in basic biology textbooks) nor the fact that it deserves recognition, but the point is that the Nobel prize in chemistry went to people who actually do chemistry, say, five times in the last 10 years (2000: conductive polymers, 2001: catalysis, 2002: mass spec and NMR, 2003: cell membranes, 2004: ubiquitin and protein degradation, 2005: metathesis, 2006: eukaryotic transcription, 2007: chemistry on surfaces, 2008: GFP and 2009: ribosomes). So, what about creating a Nobel Prize in biology? They did it for Economics in the 60s…

Well now we just have to wait for next year – and hope that people working with molecules lighter than 50 kDa will be recognized as chemists. I’m quite sure there are hosts of guys working in organic synthesis, catalysis, nanotechnology or physical chemistry – to mention a few – who deserve to get the next Nobels. And regarding Grätzel… I keep my celebrating post for next year!

Now, to be complete, I must mention that WolframAlpha comes with some limitations – or should I say, it is still being developed – but may well become an interesting alternative to other search engines. Among the limitations, if for example you enter ‘taxol’ in the query bar, you obtain a very approximate structure of the molecule, with no mention of stereochemistry, although it is of prime importance for this type of molecules. It also seems that the notion of ‘buffer’ does not (yet) exist, even though a ‘buffer calculator’ would be quite useful…

So have a look at WolframAlpha if you need simple information (on chemistry or whatever else btw) and also have a look at their blog, reporting their latest innovations and ideas.

If you drive on the highway between Bern and Zurich, you will see at some point (in Kölliken) a huge metallic, white structure somewhat looking like one of these artificial ski resorts which have been flourishing here and there around the world. However what this gigantic cage contains is not snow, but roughly 550 000 tons (!) of waste, mostly toxic chemicals, stored here completely unlabeled, unclassified and without any kind of precaution. Among others, drums with production residues from the chemical industry, electroplating sludges, phosphoric waste, oil contaminated soil, or bag containing unsorted loose waste were delivered to the landfill. In 1985, foul smells and strangely-colored dusts lead to the dump to be closed – at that time, this meant the waste was covered by around 10 meters earth… It was then observed that underground water was becoming polluted, threatening the drinking water. The authorities finally decided the site had to be decontaminated and the waste properly treated.

An impressive draining system was build to prevent water flowing under the contaminated area from polluting further ground water. Then the huge building (of a total surface equivalent to that of ten football pitches) covering the whole area was built, and kept under slightly reduced pressure such as to prevent any escape of dust, gas or odors. The access to the main building is severely restricted, and one can enter only fully equipped with airtight suit and oxygen supply. There, samples are prelevated from rust covered tanks to try and identify what had been buried 25 years ago. The waste are then separated and sent for proper treatment. This goes not without any risk, since in summer 2008 a violent fire suddenly broke out, due to fortuitous contact between magnesium and air moisture…

A view of the inside of the main building.

This is shown in this impressive video recorded by safety cameras (in Swiss-German, but the images really show how ruined the place is, and what are the working conditions. Another video (in French) can be found here telling about the landfill.

If everything goes as planned, the waste evacuation should last until 2012, and the area should ‘look like before’ in 2015. The cost of the whole operation will likely reach 1 billion swiss francs (ca. 965 millions US$) – a good sum just to repare mistakes from the past. The good news is that is was acknowledged at some point that these mistakes were putting populations and environment at risk, and appropriate arrangements were made in order to fix the situation, whatever the costs were to be. There are some lessons to take home there!

For more informations

The society responsible for the decontamination of the landfill: SMDK (in German)