Prolonged droughts likely spelled the end for Indus megacities

A section through the Dharamjali stalagmite that the authors studied. 
Photo Credit: Alena Giesche

The beginning of this arid period — starting at around 4,200 years ago and lasting for over two centuries — coincides with the reorganization of the metropolis-building Indus Civilization, which spanned present-day Pakistan and India.

The research identified three protracted droughts — each lasting between 25 and 90 years — during this arid period. “We find clear evidence that this interval was not a short-term crisis but a progressive transformation of the environmental conditions in which Indus people lived,” said study co-author Prof Cameron Petrie, from Cambridge’s Department of Archaeology.

The researchers charted historic rainfall by examining growth layers in a stalagmite collected from a cave near Pithoragarh, India. By measuring a range of environmental tracers — including oxygen, carbon and calcium isotopes — they obtained a reconstruction showing relative rainfall at seasonal resolution. They also used high-precision Uranium-series dating to get a handle on the age and duration of the droughts.

“Multiple lines of evidence allow us to piece together the nature of these droughts from different angles — and confirm they are in agreement,” said lead author of the research Alena Giesche, who conducted the research as part of her PhD in Cambridge’s Department of Earth Sciences.

Near-universal T cell immunity towards a broad range of bacteria

Neutralizing the bacterially derived cytotoxic bomb: the pneumococci lie in the background, an array of macrophages and dendritic cells are arranged around the central image of a T cell. Rows of TCRs interacting with the identified pneumolysin epitope bound to HLA (white) cross the length and breadth of the artwork, emphasizing their centrality in the immune response.
Illustration Credit: Dr. Erica Tandori.

Typically, T cells of the immune system respond to a specific feature (antigen) of a microbe, thereby generating protective immunity. As reported in the journal Immunity, an international team of scientists have discovered an exception to this rule. Namely, a group of divergent bacterial pathogens, including pneumococci, all share a small highly conserved protein sequence, which is both presented and recognized by human T cells in a conserved population-wide manner.

The study set out to understand immune mechanisms that protect against pneumococcus, a bacterial pathobiont that can reside harmlessly in the upper respiratory mucosae but can also cause infectious disease, especially in infants and older adults, which can range from middle ear and sinus infections to pneumococcal pneumonia and invasive bloodstream infections.

Most currently used pneumococcal polysaccharide-based conjugate vaccines (PCVs) are effective against 10–13 serotypes, but growing serotype replacement becomes a problem.

Versatile, High-Speed, and Efficient Crystal Actuation with Photothermally Resonated Natural Vibrations

Mechanically responsive molecular crystals are extremely useful in soft robotics, which requires a versatile actuation technology. Crystals driven by the photothermal effect are particularly promising for achieving high-speed actuation. However, the response (bending) observed in these crystals is usually small. Now, scientists from Japan address this issue by inducing large resonated natural vibrations in anisole crystals with UV light illumination at the natural vibration frequency of the crystal.

Every material possesses a unique natural vibration frequency such that when an external periodic force is applied to this material close to this frequency, the vibrations are greatly amplified. In the parlance of physics, this phenomenon is known as "resonance." Resonance is ubiquitous in our daily life, and, depending on the context, could be deemed desirable or undesirable. For instance, musical instruments like the guitar relies on resonance for sound amplification. On the other hand, buildings and bridges are more likely to collapse under an earthquake if the ground vibration frequency matches their natural frequency.

Interestingly, natural vibration has not received much attention in material actuation, which relies on the action of mechanically responsive crystals. Versatile actuation technologies are highly desirable in the field of soft robotics. Although crystal actuation based on processes like photoisomerization and phase transitions have been widely studied, these processes lack versatility since they require specific crystals to work. One way to improve versatility is by employing photothermal crystals, which show bending due to light-induced heating. While promising for achieving high-speed actuation, the bending angle is usually small (<0.5°), making the actuation inefficient.

Scientists discover rare element in exoplanet’s atmosphere

Illustration Credit: Bibiana Prinoth

The rare metal terbium has been found in an exoplanet’s atmosphere for the first time. The researchers at Lund University in Sweden have also developed a new method for analyzing exoplanets, making it possible to study them in more detail.

KELT-9 b is the galaxy’s hottest exoplanet, orbiting its distant star about 670 light years from Earth. The celestial body, with an average temperature of a staggering 4,000 degrees Celsius, has excited the world's astronomers since its discovery in 2016. A new study in Astronomy & Astrophysics reveals discoveries about the scalding-hot oddball's atmosphere.

“We have developed a new method that makes it possible to obtain more detailed information. Using this, we have discovered seven elements, including the rare substance terbium, which has never before been found in any exoplanet's atmosphere”, says Nicholas Borsato, PhD student in astrophysics at Lund University.

Terbium is a rare earth metal that belongs to the so-called lanthanoids. The substance was discovered in 1843 by the Swedish chemist Carl Gustaf Mosander in the Ytterby mine in the Stockholm archipelago. The substance is very rare in nature, and 99 percent of the world's terbium production today takes place in the Bayan Obo mining district in Inner Mongolia.

Material found in smartphone screens can be harnessed to map magnetic fields

Existing magnetic field imaging equipment tends to be large and expensive, but this research marks the next step in the development of quantum sensing.
Photo Credit: Rodion Kutsaiev

Hand-held magnetic field imaging equipment could be used in construction safety and medical diagnostics.

Smartphones could one day become portable quantum sensors thanks to a new chip-scale approach that uses organic light-emitting diodes (OLEDs) to image magnetic fields, with significant implications for use in healthcare and industry settings.  

UNSW researchers from the ARC Centre of Excellence in Exciton Science have demonstrated that OLEDs, a type of semiconductor material commonly found in flat-screen televisions, smartphone screens and other digital displays, can be harnessed to map magnetic fields. 

The latest research, led by Dr Rugang Geng and Professor Dane McCamey from the UNSW School of Physics, has been detailed in Nature Communications. 

How to increase the chance of survival in older patients with head and neck cancer

Prof. Dr. Nils Nicolay,
Photo Credit: Stefan Straube

Should patients over the age of 70 with head and neck cancer receive aggressive combined radiotherapy and chemotherapy? This is a controversial issue among patients, their families and health professionals. A large-scale international study involving Leipzig University Hospital proves the effectiveness of this combined treatment in older patients. The findings have recently been published in the journal JAMA Network Open.

As a result of demographic change, the proportion of older oncology patients is rising sharply. Compared to younger patients, cancer treatment is highly individualized due to more frequent and sometimes severe comorbidities, increasing age-related infirmities and reduced physical fitness. It is also important to consider the side effects of treatment, which can affect quality of life. The standard treatment for head and neck cancer is either surgical removal of the tumor followed by radiotherapy, or organ-preserving radiotherapy in combination with chemotherapy. The use of concomitant chemotherapy is particularly controversial because of the physical strain and side effects in older patients. So far, there is only a limited amount of trial data on the best treatment.

COVID-19 vaccine appears more effective if received around midday

A new study led by Washington University School of Medicine in St. Louis suggests that circadian rhythm — the natural cycle of physical and other changes our bodies go through in a 24-hour period — may affect the body’s response to the COVID-19 vaccine. The research suggests that vaccines given around the middle of the day may prevent more infections than those given at other times.
Image Credit: Scientific Frontline

A study from Washington University School of Medicine in St. Louis indicates that the COVID-19 mRNA vaccine may be more effective at preventing infections if doses are given around the middle of the day rather than at other times. The researchers believe circadian rhythm — the natural cycle of physical and other changes our bodies go through in a 24-hour period — may affect the body’s response to the vaccine.

Further, they found that the correlation was strongest in children and teenagers, as well as adults over age 50.

The study is published April 25 in The Journal of Clinical Investigation.

Horses living in groups are better at following human indications than horses living in individual paddocks

An illustration and photo of the research situation.
Photo Credit: Océane Liehrmann

Wild horses live in complex social groups and can move an average distance of 9–16 kilometers in a day, and cover areas up to 40 km2 in one summer. In contrast, domestic horses are kept in enclosures and groups varying in size and even in individual stalls or small paddocks.

Horses living in bigger fields or pastures are more active – they are free to move according to their needs and, for example, to look for shade or shelter against wind and rain. When living in a group, horses can fulfil their social needs, interact in complex ways with many individuals, and have enough space to avoid unwanted interactions.

“It has been observed in earlier studies that horses with access to a pasture with other horses showed better learning performance and were less aggressive towards humans than horses kept in individual stables. Therefore, we wanted to explore whether horses’ social and physical environment affect their responsiveness to human indications,” says the lead author of the study, Doctoral Researcher Océane Liehrmann from the Department of Biology at the University of Turku, Finland.

SwRI tests automated vehicles in virtual off-road environments

A virtual unmanned ground vehicle (UGV) in a simulated 3D scene rendered from a real location based on geographical data.
Image Credit: Courtesy of SwRI

Southwest Research Institute (SwRI) has created a 3D simulation tool to test automated vehicles in virtual off-road environments modeled after real-world conditions. The research expands SwRI’s investment into software-in-the-loop solutions to test connected and automated vehicles (CAVs) in scenarios ranging from congested roadways to off-road terrain. A simulated environment, or a 3D “software loop,” supports evaluations of an infinite number of scenarios that would be cost-prohibitive to test in the real world.

The technology meets U.S. Department of Defense demands for modeling and simulation tools to help advance the development of unmanned ground vehicles (UGVs), the military term for automated or autonomous vehicles.

SwRI used internal funding to develop a “pipeline” of technology with custom algorithms, off-the-shelf software, open-source tools and public map data. The project developed a “Simulation Scene Adjustment Tool” with a 3D video game-style interface to test virtual ground vehicles on off-road terrain. The simulator also creates a digital twin, a virtual representation of an automated vehicle that looks and behaves like its counterpart in the real world.

Hunting for microbes in the global ocean

Hunting for microbes in the global ocean. Sampling of seawater is performed with Niskin Bottles, which are cylindrical container used in oceanography to collect water samples containing microbes at various depths, triggered to snap shut at the desired depth.
Photo Credit: © 2022 Federico Baltar

A team of international researchers led by Federico Baltar of the University of Vienna and José M González of the University of La Laguna has identified a previously unknown group of bacteria, called UBA868, as key players in the energy cycle of the deep ocean. They are significantly involved in the biogeochemical cycle in the marine layer between 200 and 1000 meters. The results have now been published in the journal Nature Microbiology.

The deep sea, the marine layer at depths of 200 meters and more, accounts for about 90 percent of the world's ocean volume. It forms the largest habitat on Earth and is home to the largest number of microorganisms. These microorganisms contribute significantly to the biogeochemical cycles. They extract organic material, for example from phytoplankton and zooplankton, transform it and make it available again to the ecosystem as nutrients. In this way, they play a major role in the fixation and cycling of carbon. Dissolved sulfur compounds are also converted by bacteria and returned to the material cycle. 

Scientists Create a Longer-Lasting Exciton that May Open New Possibilities in Quantum Information Science

Alessandra Lanzara at Berkeley Lab.
Photo Credit: Mark Joseph Hanson

In a new study, scientists have observed long-lived excitons in a topological material, opening intriguing new research directions for optoelectronics and quantum computing. 

Excitons are charge-neutral quasiparticles created when light is absorbed by a semiconductor. Consisting of an excited electron coupled to a lower-energy electron vacancy or hole, an exciton is typically short-lived, surviving only until the electron and hole recombine, which limits its usefulness in applications. 

“If we want to make progress in quantum computing and create more sustainable electronics, we need longer exciton lifetimes and new ways of transferring information that don’t rely on the charge of electrons,” said Alessandra Lanzara, who led the study. Lanzara is a senior faculty scientist at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) and a UC Berkeley physics professor. “Here we’re leveraging topological material properties to make an exciton that is long lived and very robust to disorder.” 

In a topological insulator, electrons can only move on the surface. By creating an exciton in such a material, the researchers hoped to achieve a state in which an electron trapped on the surface was coupled to a hole that remained confined in the bulk. Such a state would be spatially indirect – extending from the surface into the bulk – and could retain the special spin properties inherent to topological surface states. 

A simple paper test could offer early cancer diagnosis

MIT engineers have designed a new nanoparticle sensor that can enable cancer diagnosis with a simple urine test. The nanoparticles (blue) carry DNA barcodes (zigzag lines) that can be cleaved by cancer-associated proteases in the body (pac-man shapes). Once cleaved, the DNA barcodes can be detected in a urine sample.
Illustration Credit: Courtesy of the researchers. Edited by MIT News

MIT engineers have designed a new nanoparticle sensor that could enable early diagnosis of cancer with a simple urine test. The sensors, which can detect many different cancerous proteins, could also be used to distinguish the type of a tumor or how it is responding to treatment.

The nanoparticles are designed so that when they encounter a tumor, they shed short sequences of DNA that are excreted in the urine. Analyzing these DNA “barcodes” can reveal distinguishing features of a particular patient’s tumor. The researchers designed their test so that it can be performed using a strip of paper, similar to an at-home Covid test, which they hope could make it affordable and accessible to as many patients as possible.

“We are trying to innovate in a context of making technology available to low- and middle-resource settings. Putting this diagnostic on paper is part of our goal of democratizing diagnostics and creating inexpensive technologies that can give you a fast answer at the point of care,” says Sangeeta Bhatia, the John and Dorothy Wilson Professor of Health Sciences and Technology and of Electrical Engineering and Computer Science at MIT and a member of MIT’s Koch Institute for Integrative Cancer Research and Institute for Medical Engineering and Science.

Study links nutrients, brain structure, cognition in healthy aging

In a study of older adults, a research team led by, from left, Christopher Zwilling, Tanveer Talukdar and Aron Barbey found that blood markers of two saturated fatty acids, along with certain omega-6, -7 and -9 fatty acids, correlated with better scores on tests of memory and were associated with larger brain structures in the frontal, temporal, parietal and insular cortices. 
Photo Credit: Fred Zwicky

In a new study, scientists explored the links between three measures known to independently predict healthy aging: nutrient intake, brain structure and cognitive function. Their analysis adds to the evidence that these factors jointly contribute to brain health in older adults. 

Reported in the Journal of Nutrition, the study found that blood markers of two saturated fatty acids, along with certain omega-6, -7 and -9 fatty acids, correlated with better scores on tests of memory and with larger brain structures in the frontal, temporal, parietal and insular cortices. 

While other studies have found one-to-one associations between individual nutrients or classes of nutrients and specific brain regions or functions, very little research takes a comprehensive look at brain health, cognition and broad dietary patterns overall, said Aron Barbey, a professor of psychology, bioengineering and neuroscience at the University of Illinois Urbana-Champaign who led the study with postdoctoral researcher Tanveer Talukdar and psychology research scientist Chris Zwilling. The three co-authors are all affiliated with the Beckman Institute for Advanced Science and Technology at the U. of I. 

Antimicrobial use in agriculture can breed bacteria resistant to first-line human defenses

E. coli bacteria
Image Credit: itstheeighthhorcrux

A new study led by the University of Oxford has shown that overuse of antimicrobials in livestock production can drive the evolution of bacteria more resistant to the first line of the human immune response. The results, published today in the journal eLife, indicate that farmed pigs and chickens could harbor large reservoirs of cross-resistant bacteria, capable of fueling future epidemics.

Drug-resistant infections are one of the most serious threats to global health, and there is an urgent need to develop new, effective antimicrobials. One promising solution could be antimicrobial peptides (AMPs). These are compounds naturally produced by most living organisms, including animals, and have important roles in innate immunity, our first line of defense against bacterial infections.

However, some AMPs are also used widely in livestock production, both to control infections and as growth promoters. This has raised concerns that agricultural AMP use may generate cross-resistant bacteria that could then overcome the human innate immune response.

 In this new study, led by the University of Oxford, researchers have demonstrated that evolution of such cross-resistant bacteria is not only possible, but also highly likely.

Condensed Matter Physics Inspires a New Model of Cellular Behavior

Model illustrating how cells exert pressure on one another, leading to extrusion.
Image Credit: Courtesy of S. Monfared

Cells are expert cooperators and collaborators. To maintain tissue health, cells talk to each other, exert pressure on each other, and kick out cells that are not contributing to the overall well-being of the collective. When it's time to get rid of a cell, the collective group initiates a process called cell extrusion. Cells can be extruded for a number of reasons—they could be cancerous, or old, or they simply could be overcrowding other cells. Extrusion is a necessary process for tissues to maintain health and integrity.

Biologists have long studied the biochemical cues and signals that underly cell extrusion, but the mechanical, physical forces involved are poorly understood.

Now, inspired by the mechanics of a phase of matter called liquid crystals, researchers have developed the first three-dimensional model of a layer of cells and the extrusion behavior that emerges from their physical interactions. From this new model, the team discovered that the more a cell is squeezed by its neighbors in a particular symmetric way, the more likely it is to get extruded from the group.