Study reveals mechanism in spruce tree that causes growth

While it’s common knowledge that trees grow when days start to become longer in the springtime and stop growing when days become shorter in the fall, exactly how this happens has not been well understood.

Now, scientists using the Canadian Light Source are offering insights into the mechanisms of how certain cells in the winter buds of Norway spruce respond to changes in seasonal light, affecting growth. The research was published in Frontiers in Plant Science.

Such knowledge allows for better predictions of how trees might respond to climate change, which could bring freezing temperatures while daylight is still long or warmer temperatures when daylight is short.

Professor Jorunn E. Olsen and YeonKyeong Lee, plant scientists at the Norwegian University of Life Sciences, along with colleagues from the University of Saskatchewan investigated winter bud cells from Norway spruce and how they differ with respect to the amount of daylight to which they were exposed.

>Read more on the Candian Light Source website

Image (from left to right, extract): plant with terminal winter bud after short day exposure for three weeks; plant with brown bud scales after short day exposure for eight weeks; plant showing bud break and new growth three weeks after re-transfer to long days following eight weeks under short days. Entire picture here.

Analysing Alzheimer’s mechanisms with synchrotron light

Researchers from the ALBA Synchrotron and the Universitat Autònoma de Barcelona (UAB) have analysed with synchrotron light different Alzheimer’s aggregates, their location and their effect in cultivated neuronal cells.

Results, published in Analytical Chemistry, pave the way to better understand the development of this disease that affects more than 30 million people worldwide.

Memory loss, communications’ difficulties, personality and behaviour changes, orientation problems … Unfortunately, these symptoms are widespread in our society, since 30 million people worldwide and 1.5 in Spain suffer from the effects of Alzheimer’s, according to the World Health Organization (WHO) and the Spanish Confederation of Family Members of Alzheimer’s and other dementias patients (CEAFA), respectively. Alzheimer’s is the most important cause of dementia and is described as a multifactorial disease that leads to neuronal cell death. Nowadays, there is no effective treatment to fight against or to prevent it.

When a person has Alzheimer’s, amyloid plaques are generated inside his brain. They are made of deposits or aggregates of the amyloid beta peptide. This peptide – which comes from a protein that is necessary for cellular functioning – tends to be aggregated by adopting different sizes and morphologies, depending on the physical and chemical conditions around it. Although it is already known that the presence of the beta amyloid peptide, together with other factors such as oxidative stress, play a key role in the onset and development of the Alzheimer’s disease, it is not still clear what causes the disease and what the consequences are.

>Read more on the ALBA website

With help from a few friends

Researchers discover the precise make-up of a molecular chaperone complex

A complex made up of three proteins, Hsp90, Sgt1, and Rar1, is thought to stabilise an important immune protein known as nucleotide-binding domain and leucine-rich repeat containing protein. While the structure of the Sgt1-Hsp90-Rar1 protein is known, the stoichiometry of the complex has remained elusive. In a paper published in Frontiers in Molecular Biosciences, Dr Chrisostomos Prodromou of the University of Sussex and Dr Minghao Zhang of the University of Oxford worked with Professor Giuliano Siligardi at the Circular Dichroism beamline (B23) at Diamond Light Source to clarify the detailed make-up of the complex. Using synchrotron radiation circular dichroism, they revealed that it consists of an Hsp90 dimer, two Sgt1 molecules, and a single Rar1 molecule. The stoichiometry of the full complex potentially allows two NLR molecules to bind, a finding which may open avenues of research into how these proteins form dimers.

>Read more on the Diamond Light Source website

Figure: (extract) The structure of the Sgt1-Hsp90-Rar1 complex with an Hsp90 dimer, two Sgt1 molecules, and a single Rar1. Entire image here.

A comparison of the etch mechanisms of germanium and silicon

Time multiplexed, deep reactive ion etching (DRIE) is a standard silicon microfabrication technique for fabricating MEMS sensors, actuators, and more recently in CMOS development for 2.5D and 3D memory devices.

At CHESS, we have adopted this microfabrication technique to develop novel x-ray optics called,Collimating Channel Arrays  (CCAs) [1], for confocal x-ray fluorescence microscopy (CXRF). Because the first CCA optics were fabricated from silicon substrates, the range of x-ray fluorescence energies for which they could be used, and hence the elements they could be used to study, was limited. Unwanted x-rays above about 11 keV could penetrate through the silicon, showing up as background and interfering with the measurement.

To solve the background problem, germanium substrates were used to fabricate the CCA optics. Germanium, which is much denser and therefore x-ray opaque than silicon, is also etch compatible with the fluorine etch chemistry for silicon DRIE. However, small differences in etch behavior between germanium and silicon can cause big differences in the outcome. Here, Genova et al JVST B [2] report a systematic comparison of  the etch mechanisms of silicon and germanium, performed with the Plasma Therm Versaline deep silicon etcher at the Cornell NanoScale Science & Technology Facility (CNF). The etch rates of silicon and germanium were compared by varying critical parameters in the DRIE process, especially the applied power and voltage used for each of 3 steps in the etch process,  on custom-designed wafers with a variety of features with systematically varying dimensions.

>Read more on the CHESS website

Image: (extract, full image here) SEM of high aspect ratio (>13:1) etched features in Si at 3.7 μm/min (a) and Ge at 3.4 μm/min (b)

LEAPS initiative is making progress

ALBA is hosting the Coordination Board and Task Force meetings of the LEAPS Initiative, the League of European Accelerator-based Photon Sources.

LEAPS is a strategic consortium initiated by the Directors of the Synchrotron Radiation and Free Electron Laser (FEL) facilities in Europe. 19 facilities are taking part with the aim to offer a step change in European cooperation, through a common vision of enabling scientific excellence, solving global challenges, and boosting European competitiveness and integration.

These days, the ALBA Synchrotron is hosting the first face-to-face meeting of the Coordination Board with the participation of all facility representatives, followed by a meeting of the Task Force which is preparing a position paper to be submitted to the European Union at the end of March 2018. Rafael Abela, from the Paul Scherrer Institute in Switzerland, is chairing this task.

>Learn more about the LEAPS initiative

Bespoke beamline engineering: the Diamond Sample Manipulator

The Surface and Interfaces village brings together six beamlines with a range of techniques for investigating structural, magnetic and electronic properties of surfaces and interfaces. Many of those beamlines rely on a Sample Manipulator to hold samples securely in an X-ray beam less than a tenth of a millimetre across, whilst also enabling them to move and rotate around multiple axes and rotate around each axis. The differing requirements of each beamline mean that the basic design of the Sample Manipulator is customised for each one.

The I09 beamline, for example, is used for studying atomic structures and electronic properties across a wide variety of surfaces and material interfaces. The Sample Manipulator on I09 makes it possible to use X-ray techniques to study monolayer adsorption and surface reconstructions in a vacuum, crystalline and non-crystalline thin films, nano-particulates, large molecules and complex organic films and magnetism and magnetic thin-films.

>Read more on the Diamond Light Source website

Image: The Sample Manipulator in situ as seen through the vacuum window.
Credit: Diamond Light Source.