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EPJ Plus Highlight - Science puts historical claims to the test

Science provides valuable dating tools for artefacts. From https://www.flickr.com/photos/ 85265584@N00/2434302237

The latest analytical techniques available to scientists can confirm the validity of historical sources in some cases, and suggest a need for reconsideration in others

As any historian will tell you, we can rarely take the claims made by our ancestors at face value. The authenticity of many of the artefacts which shape our understanding of the past have been hotly debated for centuries, with little consensus amongst researchers. Now, many of these disputes are being resolved through scientific research, including two studies recently published in EPJ Plus. The first of these, led by Diego Armando Badillo-Sanchez at the University of Évora in Portugal, analysed an artefact named ‘Francisco Pizarro’s Banner of Arms’ – believed to have been carried by the Spanish conquistador during his conquest of the Inca Empire in the 16th century. The second team, headed by Armida Sodo at Roma Tre University in Italy, investigated a colour print of Charlemagne – the medieval ruler who united much of Western Europe – assumed to be from the 16th century.

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EPJ D Highlight - Fragmenting ions and radiation sensitizers

Mass spectrum of 5-fluorouracil showing ions produced by impact with high-energy electrons.

A new study using mass spectrometry is helping piece together what happens when DNA that has been sensitized by the oncology drug 5-fluorouracil is subjected to the ionising radiation used in radiotherapy.

The anti-cancer drug 5-fluorouracil (5FU) acts as a radiosensitizer: it is rapidly taken up into the DNA of cancer cells, making the cells more sensitive to radiotherapy. However, little is known about the precise mechanism through which radiation damages cells. A team of scientists led by Peter van der Burgt at the National University of Ireland in Maynooth, Ireland have now used mass spectrometry to shed some light on this process; their work was recently published in EPJ D. A full understanding of this process could ultimately lead to new ways of protecting normal tissues from the radiation damage caused by essential cancer treatments.

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EPJ E Topical review - Liquid-liquid criticality in the dielectric constant and refractive index: A perspective

The critical region in the phase diagram of condensed matter systems such as fluids or fluid mixtures is characterized by the anomalous behaviour of specific thermodynamic properties. In a new review article published in EPJE, Patricia Losada-Pérez (Department of Physics, Université Libre de Bruxelles) describes recent progress in the understanding of the behaviour of two intimately related properties, the dielectric constant ε and the refractive index n, when approaching the liquid-liquid critical point in binary liquid mixtures.

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EPJ D Highlight - Enabling longer space missions

A Hall thruster in operation. Image by the user Dstaak at Wikimedia Commons .

Hall thrusters, which are already used to propel spacecraft and satellites on long missions, could be used for even longer ones if models for minimising surface erosion were taken into account.

The 50th anniversary of the Apollo 11 moon landing has reignited interest in space travel. However, almost any mission beyond the moon, whether manned or unmanned, will require the spacecraft to remain fully operational for at least several years. The Hall thruster is a propulsion system that is often used by craft involved in long missions. A recent study by Andrey Shashkov and co-workers at the Moscow Institute of Physics and Technology, Russia has shown how the operating lives of these systems can be further extended; their work was recently published in EPJ D.

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EPJ D Highlight - Quantum momentum

Schemes for measuring time-of-flight in classical mechanics (top) and quantum mechanics (bottom). In quantum mechanics, the classical particle is represented by a wave packet. Values of X indicate position and t time.

A new quantum-mechanical model has been developed that allows the momentum of quantum particles to be measured using a variant of the classical time-of-flight.

Quantum mechanics is an extraordinarily successful way of understanding the physical world at extremely small scales. Through it, a handful of rules can be used to explain the majority of experimentally observable phenomena. Occasionally, however, we come across a problem in classical mechanics that poses particular difficulties for translation into the quantum world. A new study published in EPJ D has provided some insights into one of them: momentum. The authors, theoretical physicists Fabio Di Pumpo and Matthias Freyberger from Ulm University, Germany, present an elegant mathematical model of quantum momentum that is accessible through another classical concept: time-of-flight.

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EPJ B Highlight - Entropy explains RNA diffusion rates in cells

RNA molecules diffuse in characteristic ways. https://commons.wikimedia.org/ wiki/File:50S-subunit_of_the_ ribosome_3CC2.png

Mathematical analysis reveals that the exponential patterns in RNA diffusion rates linked to small-scale diffusive behaviours

Recent studies have revealed that within cells of both yeast and bacteria, the rates of diffusion of RNA proteins – complex molecules that convey important information throughout the cell – are distributed in characteristic exponential patterns. As it turns out, these patterns display the highest possible degree of disorder, or ‘entropy’, of all possible diffusion processes within the cell. In new research published in EPJ B, Yuichi Itto at Aichi Institute of Technology in Japan explores this behaviour further by zooming in to study local fluctuations in the diffusion rates of RNA proteins. By associating these small-scale diffusion rates with time-varying values for entropy, he finds that the rates of change of entropy in certain time intervals are larger in areas with higher RNA diffusion rates.

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EPJ Data Science Highlight - Women’s disadvantage: because of who they are, or what they do?

Photo by Christina Morillo from Pexels

Women often find themselves strongly disadvantaged in the field of software development, in particular when it comes to open source. In a study recently published in EPJ Data Science, Orsolya Vasarhelyi and Balazs argue that this disadvantage stems from gendered behavior rather than categorical discrimination: women are at a disadvantage because of what they do, rather than because of who they are.

Continue reading the guest post by Orsolya Vasarhelyi and Balazs Vedres on the SpringerOpen blog.

EPJ D Highlight - Chemotherapy drugs react differently to radiation while in water

Chemotherapy medication reacts to radiation. Image by Michal Jarmoluk from Pixabay

A new study looked at the way certain molecules found in chemotherapy drugs react to radiation while in water, which is more similar to in the body, compared to previous research that studied them in gas

Cancer treatment often involves a combination of chemotherapy and radiotherapy. Chemotherapy uses medication to stop cancer cells reproducing, but the medication affects the entire body. Radiotherapy uses radiation to kill the cancer cells, and it is targeted to the tumour site. In a recent study, published in the journal EPJ D, researchers from the Leopold-Franzens-University Innsbruck, Austria, studied selected molecules of relevance in this context. They wanted to see how these molecules were individually affected by radiation similar to that used in radiotherapy.

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EPJ B Highlight - Spinning towards robust microwave generation on the nano scale

Snapshots of an ensemble of 100 spin-torque oscillators at different points in time, plotting values of inductance (L) against capacitance (C). Red dots show individual oscillators.

New study explains why it is not possible to couple nano-scale microwave generators known as spin-torque oscillators together in series to generate a macroscopic strength signal

Spin-torque oscillators (STOs) are nanoscale devices that generate microwaves using changes in magnetic field direction, but those produced by any individual device are too weak for practical applications. Physicists have attempted - and, to date, consistently failed - to produce reliable microwave fields by coupling large ensembles. Michael Zaks from Humboldt University of Berlin and Arkady Pikovsky from the University of Potsdam in Germany have now shown why connecting these devices in series cannot succeed, and, at the same time, suggested other paths to explore. Their work was recently published in EPJ B.

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EPJ E Highlight - Optimising structures within complex arrangements of bubbles

Optimising an arrangement of five bubbles.

Computer simulations reveal how groups of bubbles with two different areas can be optimised to minimise the lengths of the edges at which they touch, potentially allowing for stronger, cheaper structures which emulate bubbly foams.

While structures which emulate foam-like arrangements of bubbles are lightweight and cheap to build, they are also remarkably stable. The bubbles which cover the iconic Beijing Aquatics Centre, for example, each have the same volume, but are arranged in a way which minimises the total area of the structure – optimising the building’s construction. The mathematics underlying this behaviour is now well understood, but if the areas of the bubbles are not equal, the situation becomes more complicated. Ultimately, this makes it harder to make general statements about how the total surface area or, in 2D, edge length, or ‘perimeter’, can be minimised to optimise structural stability. In new research published in EPJ E, Francis Headley and Simon Cox at Aberystwyth University in the UK explore how different numbers of 2D bubbles of two different areas can be arranged within circular discs, in ways which minimise their perimeters.

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Editors-in-Chief
M. Strohmaier