Building knowledge of changes in uranium chemistry

ANSTO’s considerable expertise in characterising uranium-containing compounds has contributed to a new systematic investigation of the origins of atomic structural distortions in a family of actinide compounds.

These compounds are known as rutile-related mixed metal ternary (three-part) uranium oxides. Rutile refers to mineral compounds composed primarily of titanium dioxide.

In research published in Inorganic Chemistry, a large team of researchers used both neutron and synchrotron radiation and theoretical calculations to establish systematically precise and accurate crystal structures and uranium oxidation states in the rutile-related mixed metal ternary uranium oxide systems.

Read more on the ANSTO website

Image:  Dr Zhaoming Zhang, Principal Research Scientist, Nuclear Fuel Cycle, ANSTO

Credit: ANSTO

Perfect recipe for efficient perovskite solar cells

A long-cherished dream of materials researchers is a solar cell that converts sunlight into electrical energy as efficiently as silicon, but that can be easily and inexpensively fabricated from abundant materials. Scientists at the Helmholtz-Zentrum Berlin have now come a step closer to achieving this. They have improved a process for vertically depositing a solution made from an inexpensive perovskite solute onto a moving substrate below. Not only have they discovered the crucial role played by one of the solvents used, but they have also taken a closer look at the aging and storage properties of the solution.

Solar cells made of crystalline silicon still account for the lion’s share of roof installations and solar farms. But other technologies have long since become established as well – such as those that convert sunlight into electrical energy through use of extremely thin layers of solar-cell material deposited upon a substrate. The perovskite solar cells that Prof. Eva Unger and her team at the Helmholtz-Zentrum Berlin (HZB) are researching belong to this group. “These are the best solar cells to date that can be made using a 2D ink”, the researcher explains. “And now their efficiencies are approaching those for cells made of crystalline silicon.”

Read more on the HZB website

Image: The liquid solution of perovskite precursor, solvent, and additive flows from a slit-shaped nozzle onto the glass substrate being conveyed below.

Credit: © Jinzhao Li / HZB

Surviving the deep freeze

Key proteins protect wildlife when the temperature drops

It is hard to imagine what some fish, carrots and tiny snow fleas might have in common, but it turns out it is something key to their survival when the temperature drops below freezing.

The common trait, also shared by insects, bacteria and other microorganisms, is antifreeze proteins (AFP). As the name suggests, AFPs work “to prevent organisms from freezing or to help them survive in a frozen state,” explained Dr. Peter Davies, a professor at Queen’s University and Canada Research Chair in Protein Engineering.

Davies has been studying these unique proteins for about 40 years. His latest research, aided by X-ray diffraction techniques at the Canadian Light Source (CLS) at the University of Saskatchewan was recently published in The FEBS Journal. This study continues to build knowledge about AFP structures, their function and evolution.

Read more on the CLS website

Image: A snow flea (Granisotoma rainieri) that was collected in Japan by coauthor Dr Sakae Tsuda

Credit: Canadian Light Source (CLS)

Under wraps: X-rays reveal 1,900-year-old mummy’s secrets

Researchers used the powerful X-rays of the Advanced Photon Source to see the preserved remains of an ancient Egyptian girl without disturbing the linen wrappings. The results of those tests point to a new way to study mummified specimens.

The mummified remains of ancient Egyptians hold many secrets, from the condition of the bodies to the artifacts placed within the burial garments. Now a team of researchers has found a way to unwrap those secrets, without unraveling the mummies themselves.

Three years ago, researchers from Northwestern University, in preparation for an exhibit on campus, carefully transported a 1,900-year-old mummy to the Advanced Photon Source (APS), a U.S. Department of Energy (DOE) Office of Science User Facility at DOE’s Argonne National Laboratory. There scientists used powerful X-ray beams to peer inside the layers of linen and resin to examine the 2,000-year-old bones and objects buried within.

Read more on the Argonne National Laboratory website

Image: In 2017, Stuart Stock, center, of Northwestern University, talks with Rachel Sabino, right, of the Art Institute of Chicago while Argonne scientist Ali Mashayekhi, left, makes adjustments to the apparatus holding a 1,900-year-old Egyptian mummy.

Credit: Mark Lopez / Argonne National Laboratory.

Shedding light on the causes of arsenic contamination

An international team has used the Canadian Light Source at the University of Saskatchewan to uncover the elusive structure of two arsenic-containing compounds, information that can be used to prevent and predict arsenic contamination.

Arsenic occurs naturally in the environment, and it is present in ore deposits and the waste left behind by mining for gold, uranium, and other metals. The concern with arsenic-containing compounds, like yukonite and arseniosiderite, is that soil sources can find their way into waterways. Understanding how this happens on a structural level can help scientists — and industry — better understand how the two are formed and better protect the surrounding environment from potential arsenic contamination.

Discovered more than 100 years ago, yukonite and arseniosiderite, which are compounds of arsenic, calcium, iron and oxygen, have concealed their structure from scientists thanks to their low crystallinity. While it’s relatively easy to determine the structure of materials that have a high degree of crystallinity, because of the complexity in the way these minerals’ atoms are arranged, usual methods have come up short in painting a clear picture of their structure.

Using a special technique at the CLS called the pair distribution function (PDF), an international team of researchers from Canada, China, the USA, Italy, and Ireland was able to visualize for the first time how atoms are structured in samples of arseniosiderite, which is classified as semi-crystalline, and yukonite, which is considered a nano-crystalline mineral.

Read more on the CLS website

 Image: Specimen BM.62813 from the collections of the Natural History Museum, London 

Credit: © The Trustees of the Natural History Museum, London

The African fly of death might also save lives

For the first time, an international team of scientists recreated in the lab the molecule that allows the tsetse fly to feed on blood. It’s a powerful yet small anticoagulant with a unique and strong binding to thrombin, the key enzyme of the coagulation pathway. X-ray diffraction measurements at two synchrotron facilities ––ALBA and ESRF–– were instrumental to understand the structure and the mechanism of action of this molecule, which suggests it is also a promising platform for designing improved anticoagulant drugs.

 In the waiting rooms of health care facilities around the world, millions of patients take anticoagulants every day. These are life-saving drugs for the treatment of cardiovascular diseases, which now are also being explored for their benefits to patients with advanced symptoms of COVID-19.

And, as incredible as it may seem, the tsetse fly, responsible for the sleeping sickness disease in humans, is now on the spotlight in the efforts to develop more powerful and safer anticoagulants. 

In a study co-authored by Bárbara Calisto, researcher at the ALBA Synchrotron, an international team of scientists has become the first to recreate in the lab the molecule that the tsetse fly uses to prevent coagulation when it bites to feed. These bites are also the entry channel for the parasite that causes sleeping sickness, a life-threatening disorder, if untreated. And the reason why the tsetse fly has been dubbed as the fly of death in Africa.

Read more on the ALBA website

Image:  Bárbara Calisto at the XALOC beamline of the ALBA Synchrotron

Credit: ALBA