Research shows how to improve the bond between implants and bone

Research carried out recently at the Canadian Light Source (CLS) in Saskatoon has revealed promising information about how to build a better dental implant, one that integrates more readily with bone to reduce the risk of failure.

“There are millions of dental and orthopedic implants placed every year in North America and a certain number of them always fail, even in healthy people with healthy bone,” said Kathryn Grandfield, assistant professor in the Department of Materials Science and Engineering at McMaster University in Hamilton.

A dental implant restores function after a tooth is lost or removed. It is usually a screw shaped implant that is placed in the jaw bone and acts as the tooth roots, while an artificial tooth is placed on top. The implant portion is the artificial root that holds an artificial tooth in place.

Grandfield led a study that showed altering the surface of a titanium implant improved its connection to the surrounding bone. It is a finding that may well be applicable to other kinds of metal implants, including engineered knees and hips, and even plates used to secure bone fractures.

About three million people in North America receive dental implants annually. While the failure rate is only one to two percent, “one or two percent of three million is a lot,” she said. Orthopedic implants fail up to five per cent of the time within the first 10 years; the expected life of these devices is about 20 to 25 years, she added.

“What we’re trying to discover is why they fail, and why the implants that are successful work. Our goal is to understand the bone-implant interface in order to improve the design of implants.”

>Read more on the Canadian Light Source website

X-Ray Experiment confirms theoretical model for making new materials

By observing changes in materials as they’re being synthesized, scientists hope to learn how they form and come up with recipes for making the materials they need for next-gen energy technologies.

Over the last decade, scientists have used supercomputers and advanced simulation software to predict hundreds of new materials with exciting properties for next-generation energy technologies.

Now they need to figure out how to make them.

To predict the best recipe for making a material, they first need a better understanding of how it forms, including all the intermediate phases it goes through along the way – some of which may be useful in their own right.

Now experiments at the Department of Energy’s SLAC National Accelerator Laboratory have confirmed the predictive power of a new computational approach to materials synthesis. Researchers say that this approach, developed at the DOE’s Lawrence Berkeley National Laboratory, could streamline the creation of novel materials for solar cells, batteries and other sustainable technologies.

>Read more on the Stanford Synchrotron Radiation Lightsource at SLAC website

Image: In an experiment at SLAC, scientists loaded ingredients for making a material into a thin glass tube and used X-rays (top left) to observe the phases it went through as it was forming (shown in bubbles). The experiment verified theoretical predictions made by scientists at Berkeley Lab with the help of supercomputers (right).
Credit: Greg Stewart/SLAC National Accelerator Laboratory

Magnetization ratchet in cylindrical nanowires

A team of researchers from Materials Science Institute of Madrid (CSIC), University of Barcelona and ALBA Synchrotron reported on magnetization ratchet effect observed for the first time in cylindrical magnetic nanowires (magnetic cylinders with diameters of 120nm and lengths of over 20µm).

These nanowires are considered as building blocks for future 3D (vertical) electronic and information storage devices as well as for applications in biological sensing and medicine. The experiments have been carried out at the CIRCE beamline of the ALBA Synchrotron. The results are published in ACS Nano.

The magnetic ratchet effect, which represents a linear or rotary motion of domain walls in only one direction preventing it in the opposite one, originates in the asymmetric energy barrier or pinning sites. Up to now it has been achieved only in limited number of lithographically engineered planar nanostructures. The aim of the experiment was to design and prove the one-directional propagation of magnetic domain walls in cylindrical nanowires.

>Read more on the ALBA website

Image: (extract) Unidirectional propagation of magnetization as seen in micromagnetic simulations and XMCD-PEEM experiments. See entire image here.

Dark-field X-ray microscopy provides surprising insight on ferroelectrics

Thanks to the unique capabilities of in-situ dark-field X-ray microscopy, scientists have now been able to see the complex structures hidden deep inside ferroelectric materials. The results, published today in Nature Materials, contradict previous studies in which only the surface was studied. This revolutionary new technique will be the main feature of a new beamline for the new EBS machine currently being built at the ESRF.

“Until now we could only see the surface of the material; dark-field x-ray microscopy is like creating a window to its interior”, explains Hugh Simons, assistant professor at the Technical University of Denmark and corresponding author of the study. “It provides incredible contrast for even the subtlest structures inside these materials, giving us a much clearer picture of how they work”, he adds.

Simons, together with the team of ID06 – the beamline where the technique is being developed – studied the ferroelectric material BaTiO3, which is used every day in cars, computers and mobile phones. By imaging their internal structure at the same time as they applied an electric field on it, they could see how these internal structures behave and change dynamically.

>Read more on the European Synchrotron (ESRF) website

Image: (extract) Crosssectional dark-field x-ray microscopy maps of the embedded BaTiO3 grain. (…) the reconstructed strain map reveals the structural relationship between domain clusters. Full picture here.
Credit: H. Simons.

Brookhaven Lab scientist receives Early Career Research Program Funding

Valentina Bisogni, an associate physicist at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory, has been selected by DOE’s Office of Science to receive significant research funding as part of DOE’s Early Career Research Program.

The effort, now in its ninth year, is designed to bolster the nation’s scientific workforce by providing support to exceptional researchers during the crucial early career years, when many scientists do their most formative work. Bisogni is among a total of 84 recipients selected this year after a competitive review of proposals. Thirty winners come from DOE national laboratories and 54 from U.S. universities.

“Supporting talented researchers early in their career is key to building and maintaining a skilled and effective scientific workforce for the nation. By investing in the next generation of scientific researchers, we are supporting lifelong discovery science to fuel the nation’s innovation system,” said Secretary of Energy Rick Perry. “We are proud of the accomplishments these young scientists have already made, and look forward to following their achievements in years to come.”

Each researcher will receive a grant of up to $2.5 million over five years to cover their salary and research expenses. A list of the 84 awardees, their institutions, and titles of their research projects is available on DOE’s Early Career Research Program webpage.

>Read more on the NSLS-II at Brookhaven Lab website

Image: Valentina Bisogni is shown preparing samples at NSLS-II’s Soft Inelastic X-ray Scattering beamline, where she will conduct her research funded through DOE’s Early Career Research Program.

The 2018 Julian David Baumert Ph.D. Thesis Award

Maxwell Terban received the 2018 Julian Baumert Ph.D. Thesis Award at this year’s Joint CFN and NSLS-II Users’ Meeting.

Maxwell Terban, a postdoctoral researcher at the Max-Plank Institute for Solid State Research, Stuttgart, is this year’s recipient of the Julian Baumert Ph.D. Thesis Award. Terban was selected for developing new research methods, based around a technique called pair distribution function (PDF), for extracting and analyzing structural signatures from materials. His research incorporated measurements from the now-closed National Synchrotron Light Source (NSLS) and the recently opened National Synchrotron Light Source II (NSLS-II)—a U.S. Department of Energy (DOE) Office of Science User Facility located at Brookhaven National Laboratory.

Each year, the Baumert Award is given to a researcher who has recently conducted a thesis project that included measurements at NSLS or NSLS-II. The award was established in memory of Julian David Baumert, a young Brookhaven physicist who worked on x-ray studies of soft-matter interfaces at NSLS.

Terban holds a bachelor’s degree in chemical engineering from the University of Massachusetts, Amherst, and a master’s degree in materials science and engineering from Columbia University. He graduated with a Ph.D. in materials science and engineering from Columbia University in 2018, and completed his doctoral dissertation under the guidance of Simon Billinge, a professor of materials science and engineering and applied physics and mathematics at Columbia.

>Read more on the NSLSI-II at Brookhaven National Laboratory website

Image: Maxwell Terban, a postdoctoral researcher at the Max-Plank Institute for Solid State Research, Stuttgart, is this year’s recipient of the Julian Baumert Ph.D. Thesis Award.

Molecular Anvils Trigger Chemical Reactions

Tripling the energy storage of lithium-ion batteries

Scientists have synthesized a new cathode material from iron fluoride that surpasses the capacity limits of traditional lithium-ion batteries.

As the demand for smartphones, electric vehicles, and renewable energy continues to rise, scientists are searching for ways to improve lithium-ion batteries—the most common type of battery found in home electronics and a promising solution for grid-scale energy storage. Increasing the energy density of lithium-ion batteries could facilitate the development of advanced technologies with long-lasting batteries, as well as the widespread use of wind and solar energy. Now, researchers have made significant progress toward achieving that goal.

A collaboration led by scientists at the University of Maryland (UMD), the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory, and the U.S. Army Research Lab have developed and studied a new cathode material that could triple the energy density of lithium-ion battery electrodes. Their research was published on June 13 in Nature Communications.

>Read more on the NSLS-II at Brookhaven National Lab website

Image: Brookhaven scientists are shown at the Center for Functional Nanomaterials. Pictured from left to right are: (top row) Jianming Bai, Seongmin Bak, and Sooyeon Hwang; (bottom row) Dong Su and Enyuan Hu.

Insulator metal transition at the nanoscale

An international team of researchers has been able to probe the insulator-conductor phase transition of materials at the nanoscale resolution. This is one of the first results of MaReS endstation of BOREAS beamline.

Controlling the flow of electrons within circuits is how electronic devices work. This is achieved through the appropriate choice of materials. Metals allow electrons to flow freely and insulators prevent conduction. In general, the electrical properties of a material are determined when the material is fabricated and cannot be changed afterwards without changing the material. However, there are materials that can exhibit metal or insulator behaviour depending on their temperature. Being able switch their properties, these materials could lead to a new generation of electronic devices.

Vanadium Dioxide (VO2) is one such material. It can switch from an insulating phase to a metallic phase just above room temperature, a feature exploited already for sensors. However, the reason why the properties of this material change so dramatically has been a matter of scientific debate for over 50 years.

One of the challenges in understanding why and how this switch occurs is due to a process called phase separation. The insulator-metal phase transition is similar to the ice to liquid transition in water. When ice melts, both liquid and solid water can coexist in separate regions. Similarly, in VO2, insulating and metallic regions of the material can be coexisting at the same time during the transition. But unlike water, where the different regions are often large enough to see with the naked eye, in VOthis separation occurs on the nanoscale and it is thus challenging to observe. As a result, it has been hard to know if the true properties of each phase, or the mixture of both phases, are being measured.

>Read more on the ALBA Synchrotron website

Image: (extract, original here) reconstructed holograms at the vanadium and oxygen edges (518, 529, and 530.5 eV) used to encode the intensities of the three color channels of an RGB (red, green, blue) image. At 330 K, an increase in intensity of the green channel, which probes the metallic rutile phase (R) through the d∥ state, is observed in small regions. As the sample is heated further, it becomes increasingly clear that the blue channel, which probes a intermediate insulating M2 phase, also changes but in different regions. At 334 K, three distinct regions can be observed corresponding to the insulating monoclinic M1, M2, and metallic R phases. As the temperature increases, the R phase dominates. The circular field of view is 2 μm in diameter. (taken from Vidas et al, Nanoletters, 2018).

Video presentation of thesis at NanoMAX

In April 2018, Karolis Parfeniukas (image) defended the first thesis to be fully completed at one of the new MAXIV beamlines called NanoMAX Here’s an interview with Karolis about this project making zone plates to improve focusing of the X-ray beam. Thesis from KTH university, Royal Institute of Technology in Stockholm. PLease watch here the presentation of his research at MAX IV Laboratory:

>Read more here about MAX IV Laboratory

Rational optimization of organic solar-cell materials

Taking additive manufacturing’s heart beat

Additive manufacturing, or 3D printing, builds objects by adding layers and it is emerging as a more flexible and reliable way of manufacturing complex structures in the aerospace, engineering and biomedical industries. A British team is at the ESRF’s ID19 to see into the heart of the process and understand it.

“I would not want to ship this equipment on an aeroplane”, Chu Lun Alex Leung said, scientist from the University of Manchester. “It was too precious to leave it in the hands of third parties”, he added. Instead of coming to the ESRF by aeroplane, Leung and his colleagues endured the 12-hour drive in a rental van all the way from Oxfordshire (UK) to the ESRF to make sure their unique equipment arrived safely.

Leung was referring to the laser additive manufacturing (LAM) process replicator, or LAMPR for short, a machine himself and colleagues at the Research Complex at Harwell have developed that 3D prints polymers, metals and ceramics while ESRF’s X-rays probe the heart of the process – the melting and solidification of powders to form complex 3D printed components.

>Read more on the European Synchrotron website

Image: The team on the beamline, next to the laser additive manufacturing (LAM) process replicator. Front row: Margie P. Olbinado, Yunhui Chen. Back row: Sam Tammas-Williams, Lorna Sinclair, Peter D. Lee, Chu lun alex Leung, Samuel Clark, Sebastian Marussi.
Credit: C.Argoud

World’s strongest bio-material outperforms steel and spider silk

Novel method transfers superior nanoscale mechanics to macroscopic fibres

At DESY’s X-ray light source PETRA III, a team led by Swedish researchers has produced the strongest bio-material that has ever been made. The artifical, but bio-degradable cellulose fibres are stronger than steel and even than dragline spider silk, which is usually considered the strongest bio-based material. The team headed by Daniel Söderberg from the KTH Royal Institute of Technology in Stockholm reports the work in the journal ACS Nano of the American Chemical Society.

The ultrastrong material is made of cellulose nanofibres (CNF), the essential building blocks of wood and other plant life. Using a novel production method, the researchers have successfully transferred the unique mechanical properties of these nanofibres to a macroscopic, lightweight material that could be used as an eco-friendly alternative for plastic in airplanes, cars, furniture and other products. “Our new material even has potential for biomedicine since cellulose is not rejected by your body”, explains Söderberg.

The scientists started with commercially available cellulose nanofibres that are just 2 to 5 nanometres in diameter and up to 700 nanometres long. A nanometre (nm) is a millionth of a millimetre. The nanofibres were suspended in water and fed into a small channel, just one millimetre wide and milled in steel. Through two pairs of perpendicular inflows additional deionized water and water with a low pH-value entered the channel from the sides, squeezing the stream of nanofibres together and accelerating it.

>Read more on the PETRA III at DESY website

Image: The resulting fibre seen with a scanning electron microscope (SEM).
Credit: Nitesh Mittal, KTH Stockholm

Understanding how alkaline treatment affects bamboo

In China, bamboo is a symbol of longevity and vitality, able to survive the hardest natural conditions and remain green all year round. In a storm, bamboo stems bend but do not break, representing the qualities of durability, strength, flexibility and resilience1.

Bamboo is a traditional construction material in Asia. Its strength and flexibility arise from its hollow stems (‘culms’) made from distinct material components. The solid outer shell of the culm is made primarily from longitudinal fibres. A higher density at the outer wall makes it stronger than the inner regions, and results in remarkable stiffness and flexural strength. Running through the centre of bamboo stem are parenchyma cells that store and channel the plant’s nutrients.

At the micro-/nano-scale both the fibres and the matrix contain cellulose nano-fibrils of the same type. However, the structural arrangement of the two materials result in contrasting mechanical properties. Individual fibres may reach a strength of 900 MPa, whilst the matrix can only resist about 50 MPa. There is also a considerable difference in their elastic properties, with the fibres being much stiffer than the matrix.

Bamboo is often treated with alkaline solutions, to modify these properties. Alkaline treatments can turn this rapidly renewable and low-cost resource into soft textiles, and extract fibres to be used in composite materials or as biomass for fuel.

>Read more on the Diamond Light Source website

Image: Dr Enrico Salvati on the B16 beamline at Diamond.

Spin and charge frozen by strain

In the development of next-generation microelectronics, a great deal of attention has been given to the use of epitaxy (the deposition of a crystalline overlayer on a crystalline substrate) to tailor the properties of materials to suit particular applications. Correlated electron systems provide an excellent platform for the development of new microelectronic devices due to the presence of multiple competing ground states of similar energy. In some cases, strain can drive these systems between two or more such states, resulting in phase transitions and dramatic changes in the properties of the material. Often, the specific mechanism by which strain accomplishes such a feat is unknown. This was precisely the case in lanthanum cobaltite, LaCoO3, which undergoes a strain-induced transition from paramagnet to ferromagnet, until a recent study carried out at the U.S. Department of Energy’s Advanced Photon Source (APS) revealed the intriguing microscopic phenomena at work in this system. These phenomena may play a role in spin-state and magnetic-phase transitions, regardless of stimulus, in many other correlated systems.

Lanthanum cobaltite is a perovskite, which means the structure can be thought of as made up of distorted cubes with cobalt at the cube centers, oxygen at the cube faces, and lanthanum at the cube corners. The cobalt ions have a nominal 3+ valence, meaning they lose three electrons to the neighboring oxygen ions. Bulk LaCoO3 is paramagnetic (that is, having a net magnetization only in the presence of an externally applied magnetic field) above 110 Kelvin, and non-magnetic below that temperature. In its ground state, all the electrons on a given cobalt ion are paired, meaning their magnetic spins cancel each other out. These are so-called low-spin (LS) Co3+ ions, and when all of the cobalt ions are in this form, LaCoO3 is non-magnetic.

>Read more on the Advanced Photon Source website

Image: Upper left: Resonant x-ray scattering at the cobalt K-edge. Inversion of the spectra at the reflections shown indicates the presence of charge order. Upper right: X-ray diffraction reciprocal space maps at the (002) and (003) reflection indicating the high epitaxial quality of the films. The satellite peaks result from lattice modulations associated with the reduced symmetry in the film. Lower left: Schematic crystal structure of epitaxial LaCoO3 showing the arrangement of cobalt sites with different charge and spin. The circulated charge transfer from oxygen to the different cobalt sites is also shown. Lower right: Calculated total energy as a function of the difference between the in-plane Co-O bond lengths of HS and LS cobalt ions (∆rCo-O).

Scientists find a new way to make novel materials by ‘un-squeezing’

Like turning a snowball back into fluffy snow, a new technique turns high-density materials into a lower-density one by applying the chemical equivalent of ‘negative pressure.’

Some materials can morph into multiple crystal structures with very different properties. For instance, squeezing a soft form of carbon produces diamond, a harder and more brilliant form of carbon. The Kurt Vonnegut novel “Cat’s Cradle” featured ice-nine, a fictional form of water with a much higher melting point than regular ice that threatened to irreversibly freeze all the water on Earth.

These materials are called polymorphs, and they’re commonly made by applying pressure, or squeezing. Scientists looking for new materials would also like to do the opposite – apply “negative pressure” to stretch a material’s crystal structure into a new configuration. In the past, this approach seemed to require negative pressures that are difficult if not impossible to achieve in the lab, plus it risked pulling the material apart.

Now researchers at the Department of Energy’s National Renewable Energy Laboratory (NREL) have found a way to create the equivalent of negative pressure by mixing two materials together under just the right conditions to make an alloy with an airier and entirely different crystal structure and unique properties.

>Read more on the SSRL website

Image: SLAC staff scientists Laura Schelhas and Kevin Stone at an experimental station at the Stanford Synchrotron Radiation Lightsource, where they used X-rays to measure the structure of a novel ‘negative pressure’ material created at NREL.
Credit: Matt Beardsley/SLAC National Accelerator Laboratory