All That Matters

Sixty years ago this month Nature published the famous paper by Watson and Crick solving the structure of DNA. At the time many researchers pursued this goal, made difficult by the complexity of the DNA itself. A key contribution to the solution of the puzzle was the x-ray diffraction data provided by Rosalind Franklin. Indeed, without x-ray diffraction experiments this discovery would have been almost impossible at the time.

Rosalind Franklin’s x-ray diffraction image of DNA. (c) Nature Magazine. Franklin, R. & Gosling, R. G. Nature 171, 740-741 (1953) – doi:10.1038/171740a0

The way x-ray crystallography works is that a beam of x-rays is directed at a crystal, where the x-rays bounce off the atoms. Because the atoms in a crystal are periodically arranged, the x-rays form complex but regular patterns (such as the one seen for DNA). A detailed analysis of these patterns enables the precise determination of the crystal structure.

To this day such experiments aren’t easy. They require relatively large crystals and typically are done at major facilities such as electron synchrotrons. The synthesis of the crystals for these experiments can often be very difficult.

Yasuhide Inokuma, Makoto Fujita and colleagues from the University of Tokyo in Japan  and the University of Jyväskylä in Finland have now developed a clever method that does away with many limitations of x-ray crystallography. Their method works with tiny amounts of material, only about a half to 5 micrograms are enough. This is around a millionth of a gram – truly tiny. The difference between a microgram and a gram is the same as that between a gram and a metric ton. In addition, another major advance of their method is that the target molecules don’t even need to be in a crystalline state. [...]

Today the University of Düsseldorf in Germany has revoked the doctorate of the German Federal Minister of Education and Research, Annette Schavan, following accusations of plagiarism.  She denies the accusations and has announced to continue the fight for her degree in court. This is the second case in two years of a German federal minister losing their doctorate based on accusations of plagiarism, the other being Karl-Theodor zu Guttenberg, the former Minister of Defence.

I don’t want to comment on these specific cases, but focus on the broader issues here. To me these cases are a reminder that in some countries (such as Germany…) doctorate degrees mean far too much, and in some cases are sought after also because they give considerable social recognition. They are used to advance careers in completely unrelated careers, and in this way create entrance barriers based on unnecessary criteria. This is very wrong. [...]

The Boeing 787 Dreamliner is the most recent major new aircraft design from Boeing, and the manufacturer’s most fuel-efficient plane. I have never had the pleasure of being passenger on one of these, but the design is certainly very modern. Composite materials are widely used in the aircraft, which is key to the plane’s fuel efficiency and explains the popularity of the plane. With more than 800 orders in the books, Boeing was also on a good track to break even commercially.

Then, on January 16 the FAA grounded all 787, following a number of technical problems. Earlier, the Japanese airlines ANA and JAL had already suspended all 787 flights, which was a significant signal because combined these two airlines operate almost half of the 787 delivered to date. Aside from a number of other technical issues such as a fuel leak, a key reason to ground the entire fleet has been two incidences where the back-up batteries overcharged and overheated such that there was the danger of fire on board. But how big a deal are these battery incidents? [...]

How do you measure mass with high precision? This is not an easy question, as it is very difficult to measure the weight of something with the same ultra-high precision with which atomic clocks measure time. To this day, the kilogram is defined by a piece of metal made of platinum and iridium that is stored in Paris. If you want to know with absolute precision the weight of something, you would have to compare it to this particular piece of metal. This does not only seem very imprecise and old-fashioned, it also leads to a range of issues. Only last week there have been news reports of the official kilogram piece and its various official copies all over the world slowly gaining weight from dirt on their surface.

It comes as no surprise that physicists are searching for more precise ways to measure weight, and the method now published in Science by Holger Müller and colleagues from Berkeley is one of the most elegant and beautiful ones that I have seen in a long time. It is based on a quantity that we know very well how to measure with very high precision – time. The question is how to measure the mass of something by telling the time. [...]

Usually we tend to think about temperature as being related to the motion of atoms. At lower temperatures, atomic motions slow down. Absolute zero, defined as zero Kelvin or −273.15 degrees Celsius, then is the point where all atomic motion stops. But what comes beyond that, does something like a negative absolute temperature exist? Indeed, as Ulrich Schneider and colleagues from Munich have now demonstrated impressively in this week’s issue of Science, it does. [...]

There is a lot of buzz in the physics community about a new topological insulator: samarium hexaboride, SmB₆. The reason why any major discovery about topological insulators seems to be big news is that these materials have some unique electrical characteristics that make them not only very interesting from a fundamental point of view but also for electronic applications.

Topological insulators are electrically insulating in their interior, but at the surface they do conduct current. Moreover, the surface currents are topologically protected (hence the name), which means that the electrons that carry those currents don’t veer off the track easily and maintain their properties over long distance. Although a number of topological insulator compounds are known, the problem so far has been that it has been difficult to fabricate these with sufficient purity such that the interior was indeed insulating. This has been a problem, as the electrical current inside the materials just overwhelms the surface properties. [...]