Molluscs use thermodynamics to create complex morphologies with exceptional properties

An international team has found how some molluscs create their complex structures.

Their work provides new tools for novel bioinspired and biomimetic bottom-up material design.
Nature serves as a source of inspiration for scientists and engineers thanks to the complex material architectures that make up some living organisms. These materials carry out essential functions, ranging from structural support and mechanical strength, to optical, magnetic or sensing capabilities. One example of this are molluscan shells, made of mineralized tissues organised in mineral-organic hierarchical functional architectures.

Molluscs appeared more than 500 million years ago, and they have developed hard and stiff mineralised outer shells for structural support and protection against predation. Their shells consist of mineral-organic composite structures made of calcium carbonates, mostly calcite and aragonite. The different shells exhibit a large variety of intricate three-dimensional assemblies with superior mechanical properties.

>Read more on the European Synchrotron website

Garnet gemstones contain secrets of our seismic past

Somewhere in the world an earthquake is occurring. In general, it will be a small tremor, an earthquake of magnitude two or lower, which humans cannot even feel. However when a major earthquake occurs, of magnitude 7 or above, it can cause devastating damage, events like tsunamis, and loss of life. These type of quakes, like the 2011 event in Japan and 2015 Nepalese events, happen around 20 times each year worldwide.

Large earthquakes tend to occur in subduction zones, such as the so-called Ring of Fire, where tectonic plates meet and one is bent and forced underneath the other, into the mantle of the earth. As well as leading to earthquakes, subduction also causes the composition and structure of the rock itself to become altered, in a process called high-pressure/low temperature metamorphism.

Metamorphism can take a variety of forms, in a number of different rocks, but one that is of particular interest is a type called rhythmic major-element zoning, in the mineral garnet. If found it can be a sign that subduction has occurred, and it can act as a record of seismicity in the crust of our Earth.

>Read more on the Diamond Light Source website

NSRRC User, Jennifer Kung elected as a MSA Fellow

First female scientist ever awarded MSA fellowship in Asia.

NSRRC user, Jennifer Kung is among the 11 new elected fellows for 2018, announced by the Mineralogical Society of America (MSA) Council at its Fall Council Meeting in Seattle, WA, USA. She is the only recipient from Taiwan, as well as the first female scientist ever awarded MSA fellowship in Asia.

Prof. Kung is an Associate Professor in Earth Science at National Cheng-Kung University. She runs “Mineral and Rock Physics Lab” to investigate the behaviors of earth materials under high pressure and high temperature using the knowledge of crystal chemistry, mineral physics to understand the interior of the Earth. The major research methods she employs include X-ray diffraction, vibrational spectroscopy and ultrasonic measurements in conjunction with high pressure facilities, like large volume high pressure apparatus or diamond anvil.

 

Identification of a mineral that until now was only present in meteroites

X-ray microdiffraction experiments were done to determine the crystalline structure of chladniite

Researchers from the Institute of Materials Science of Barcelona (ICMAB-CSIC), the Autonomous University of Barcelona (UAB), and the National University of Córdoba (Argentina), in collaboration with researchers of the ALBA Synchrotron, have identified a mineral in the region of Córdoba (Argentina), until now only observed in meteorites.

The study, published in European Journal of Mineralogy, affirms that the mineral is chladniite, a complex phosphate belonging to the fillowite group, which contains sodium, calcium, magnesium and iron, and has a trigonal structure. It has been found in a pegmatite, an igneous (magmatic) rock, formed from the slow cooling and solidification of magma.

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Speedy X-Ray Detector Arrives at NSLS-II

Advanced detector fuels discovery by allowing users to collect massive datasets in less time.

The National Synchrotron Light Source II (NSLS-II), a DOE Office of Science User Facility at the U.S. Department of Energy’s Brookhaven National Laboratory, is a truly international resource. Geoscientists from Australia and France recently trekked across the globe to aim NSLS-II’s tiny, intense beams of x-ray light at thin samples of nickel-rich mineral gathered from a mine in far-off Siberia. They scanned these slices of geological material to see what other chemical elements were associated with the nickel. The group also examined slices of minerals grown in a lab, and compared results from the two sample suites to learn how massive metal deposits form.

Their experiment was the first to use a newly installed x-ray detector, called Maia, mounted at NSLS-II’s Submicron Resolution X-Ray Spectroscopy (SRX) beamline. Scientists from around the world come to SRX to create high-definition images of mineral deposits, aerosols, algae—just about anything they need to examine with millionth-of-a-meter resolution. Maia, developed by a collaboration between NSLS-II, Brookhaven’s Instrumentation Division and Australia’s Commonwealth Scientific and Industrial Research Organization (CSIRO), can scan centimeter-scale sample areas at micron scale resolution in just a few hours—a process that used to take weeks.

Chemistry at the protein-mineral interface

The nucleation site of iron mineral in human L ferritin revealed by anomalous -ray diffraction

Iron ions have crucial functions in every living organism being essential for cellular respiration, DNA synthesis, detoxification of exogenous compounds, just to provide a few examples. However, the redox properties of iron ions can also cause the occurrence of deleterious free-radicals. For these reasons, when unnecessary, iron must be kept in appropriate forms unable to cause damage. Nature evolved a special protein cage, called ferritin, consisting of 24 subunits arranged to form a hollow sphere with an internal diameter of about 80 Å where mineralized iron is stored, generally under the form of insoluble ferric oxides.

In mammals, two types of subunits build-up the 24-mer ferritins: the ‘heavy’ (H) and the ‘light’ (L). These subunits differ not only in molecular weight (21.2 kDa for H and 20.0 kDa for L) but, mainly, in function. The H subunit is able to catalyze the rapid oxidation of Fe2+ to Fe3+ followed by transfer in the storage cavity. On the contrary, the L-chain does not possess catalytic activity, but it is still able to mineralize ferric ions upon spontaneous oxidation by dioxygen of captured Fe2+. Despite the intensive research on ferritin chemistry, the mechanisms of iron oxidation and storage to form mineral nanoparticles inside the ferritin cavity are still to be fully established.

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