SLS

Reorganisation of the brain and sense organs could be the key to the evolutionary success of vertebrates, one of the great puzzles in evolutionary biology, according to a paper by an international team of researchers, published today in Nature. The study claims to have solved this scientific riddle by studying the brain of a 400 million year old fossilized jawless fish à an evolutionary intermediate between the living jawless and jawed vertebrates.

An international team of researchers has developed a new method for making detailed X-ray images of brain tissue, which has been used to make the myelin sheaths of nerve fibres visible. Damage to these protective sheaths can lead to various disorders, such as multiple sclerosis. The facility for creating these images of the protective sheaths of nerve cells is being operated at the Swiss Light Source (SLS), at the Paul Scherrer Institute.

At the beginning of the process of sight, light interacts with a protein molecule called Rhodopsin. This molecule contains the actual light sensor that is stimulated by the incoming light and changes its form, in order to trigger the rest of the process. Researchers have now managed to determine the exact structure of the Rhodopsin molecule in its short-lived, excited state. From this, they have obtained a precise picture of the first step of the process of sight.

In menschlichen Zellen finden sich stammesgeschichtlich sehr alte Funktionseinheiten, die als Centriolen bezeichnet werden. Ein Forscherteam vom PSI und der ETH Lausanne hat nun erstmals ein Modell für die Bildung der Centriolen vorgestellt. Das erstaunende Ergebnis ist, dass die Neuner-Symmetrie des Centriols durch die Fähigkeit eines einzelnen Proteins sich selbst zu organisieren zustande kommt.This news release is only available in French and German.

Ribosomes are the protein factories of the living cell and themselves very complex biomolecules. Now, a French research group has for the first time determined the structure of the ribosome in a eukaryotic cell à a complex cell containing a cell nucleus. An important part of the experiments was performed with synchrotron light at the Swiss Light Source SLS of the Paul Scherrer Institute.

For decades researchers have searched for magnetic monopoles à isolated magnetic charges that can move freely like electric charges. Now a team of researchers from the Paul Scherrer Institute and University College Dublin have been able to produce monopoles in the form of quasiparticles in an assembly of nanoscale magnets and have directly observed how they move.

High-resolution method for computed nano-tomography developedA novel nano-tomography method developed by a team of researchers from the Technische Universität München, the Paul Scherrer Institute and the ETH Zurich opens the door to computed tomography examinations of minute structures at nanometer resolutions. The new method makes possible, for example, three-dimensional internal imaging of fragile bone structures.

Many important materials are composed of several phases. When such a material is heated, atoms move from one phase to another, which changes the distribution of the phases à and thus, the properties of the material. A team of researchers has now shown that for an important case, there is a general law describing this process that is valid for all classes of materials.

Semiconductors made from polymer materials are becoming increasingly important for the electronics industry à as a basis for transistors, solar cells or LEDs. Usually, they consist of more than one substance as they get their particular electric properties only when several materials are blended. Researchers from the Paul Scherrer Institute and the University of Cambridge have developed a method that allows them to determine the detailed structure of the material.

Images generated using the phase-contrast technique allow one to distinguish between tissue types such as muscle, cartilage, tendons or soft-tissue tumours that look virtually identical in conventional X-ray images. Researchers at the Paul Scherrer Institute and the Chinese Academy of Science have further developed the technique to make it easier to use in the future. This could help in the detection of tumours or in the identification of hazardous objects in luggage.