. Scientific Frontline

Friday, December 24, 2021

Templating approach stabilizes ‘ideal’ material for alternative solar cells

Artist's impression of formamidinium (FA)-based crystal 
Credit: Tiarnan Doherty
The researchers, from the University of Cambridge, used an organic molecule as a ‘template’ to guide perovskite films into the desired phase as they form. Their results are reported in the journal Science.

Perovskite materials offer a cheaper alternative to silicon for producing optoelectronic devices such as solar cells and LEDs.

There are many different perovskites, resulting from different combinations of elements, but one of the most promising to emerge in recent years is the formamidinium (FA)-based FAPbI3 crystal.

The compound is thermally stable and its inherent ‘bandgap’ – the property most closely linked to the energy output of the device – is not far off ideal for photovoltaic applications.

For these reasons, it has been the focus of efforts to develop commercially available perovskite solar cells. However, the compound can exist in two slightly different phases, with one phase leading to excellent photovoltaic performance, and the other resulting in very little energy output.

“A big problem with FAPbI3 is that the phase that you want is only stable at temperatures above 150 degrees Celsius,” said Tiarnan Doherty from Cambridge’s Cavendish Laboratory, the paper's first author. “At room temperature, it transitions into another phase, which is really bad for photovoltaics.”

Recent solutions to keep the material in its desired phase at lower temperatures have involved adding different positive and negative ions into the compound.

Wednesday, December 22, 2021

ESO telescopes help uncover largest group of rogue planets

This artist’s impression shows an example of a rogue planet with the Rho Ophiuchi cloud complex visible in the background. Rogue planets have masses comparable to those of the planets in our Solar System but do not orbit a star, instead roaming freely on their own. 
Credit: ESO/M. Kornmesser

Rogue planets are elusive cosmic objects that have masses comparable to those of the planets in our Solar System but do not orbit a star, instead roaming freely on their own. Not many were known until now, but a team of astronomers, using data from several European Southern Observatory (ESO) telescopes and other facilities, have just discovered at least 70 new rogue planets in our galaxy. This is the largest group of rogue planets ever discovered, an important step towards understanding the origins and features of these mysterious galactic nomads.

Tuesday, December 21, 2021

Study shows common flower species holds promise for beneficial psychedelic drugs

Thanks to a symbiotic fungus, many species of morning glories contain elements of powerful psychedelic drugs, according to a new Tulane University study published in the journal Communications Biology.

The seeds of the common tropical vine, whose namesake trumpet-like blooms only open in the morning, contain compounds that could be useful for treating mental and physical diseases as well as promoting well-being, said plant and fungal biologist Keith Clay, chairman of the Tulane Department of Ecology and Evolutionary Biology.

Researchers from Tulane, Indiana University and the West Virginia University obtained samples of morning glory seeds from worldwide herbarium collections and screened them for ergot alkaloids, a compound associated with the hallucinogenic drug LSD, but which have also been used for treating migraine headaches and Parkinson’s disease.

Many morning glory species contain high concentrations of bioactive ergot alkaloids that are produced by specialized fungal symbionts passed down from mother plant to offspring through their seeds. Researchers found that one-quarter of over 200 species tested contained ergot alkaloids and were therefore symbiotic.

First model to predict lifetime risk of heart failure

Imagine visiting the doctor, answering a few basic questions and getting an on-the-spot estimate of whether you’ll experience heart failure in the next 30 years.

Such a model now exists, thanks to a new Northwestern Medicine study, which derived and validated the first set of risk prediction models for lifetime risk of heart failure.

The ability to identify who is at greatest risk for heart failure — especially among high-risk young adult populations — will allow physicians to start prevention measures sooner.

“Once someone develops symptoms of heart failure, the window for prevention has closed, which is a missed opportunity, given that the risk of dying in the five years after diagnosis is 50%, similar to a cancer diagnosis,” said corresponding study author Dr. Sadiya Khan, assistant professor of cardiology and epidemiology at Northwestern University Feinberg School of Medicine and a Northwestern Medicine physician.

Prior to this work, no models existed for estimating long-term risk for heart failure. Short-term models exist that estimate heart-failure risk in the next five to 10 years, But those aren’t as effective for young adults who may not develop heart failure until they are older.

Now, for the first time, the model will allow doctors to estimate a person’s risk of developing heart failure in the next 30 years based on their current risk factor levels, such as body mass index, blood pressure, cholesterol, diabetes and smoking status. The scientists are currently working on an online tool that could be used by physicians.

Exquisitely preserved embryo found inside fossilized dinosaur egg

Dinosaur egg and embryo reconstruction
Credit: Julius Csotonyi

A 72- to 66-million-year-old embryo found inside a fossilized dinosaur egg sheds new light on the link between the behavior of modern birds and dinosaurs, according to a new study.

The embryo, dubbed ‘Baby Yingliang’, was discovered in the Late Cretaceous rocks of Ganzhou, southern China and belongs to a toothless theropod dinosaur, or oviraptorosaur. Among the most complete dinosaur embryos ever found, the fossil suggests that these dinosaurs developed bird-like postures close to hatching.

Scientists found the posture of ‘Baby Yingliang’ unique among known dinosaur embryos — its head lies below the body, with the feet on either side and the back curled along the blunt end of the egg. Previously unrecognized in dinosaurs, this posture is similar to that of modern bird embryos.

In modern birds, such postures are related to ‘tucking’ — a behavior controlled by the central nervous system and critical for hatching success. After studying egg and embryo, researchers believe that such pre-hatching behavior, previously considered unique to birds, may have originated among non-avian theropods.

Spray-on coating could make solar panels snow-resistant


In an advance that could dramatically improve the productivity of solar panels in cold climates, a University of Michigan-led team has demonstrated an inexpensive, clear coating that reduced snow and ice accumulation on solar panels, enabling them to generate up to 85% more energy in early testing.

The coating is made chiefly of PVC or PDMS plastic and silicon or vegetable-based oils. It can be sprayed or brushed on in cold weather and, in its current iteration, can keep shedding snow and ice for up to a year.

“Renewable energy is really taking off right now, but snow is a huge problem in northern climates,” said Anish Tuteja, U-M professor of materials science and engineering, who led the study in collaboration with Sandia National Laboratories and the University of Alaska.

“Solar panels might lose 80 or 90% of their generating capacity in the winter. So figuring out a way for them to continue generating energy throughout the year was an exciting challenge,” he said.

While Tuteja’s lab has developed a number of effective ice-shedding coatings in the past, he explains that designing a coating that can passively shed both snow and ice represents a special challenge.

“Ice is relatively dense and heavy, and our previous coatings used its own weight against it,” Tuteja said. “But snow can be 10 times less dense than ice, so we weren’t at all certain that the tricks we use on ice would translate to snow.”

Extinct reptile discovery reveals earliest origins of human teeth, study finds

Infographic showing differentiated teeth
Credit: Dr Suresh Singh
A new extinct reptile species has shed light on how our earliest ancestors became top predators by modifying their teeth in response to environmental instability around 300 million years ago.

In findings published in Royal Society Open Science, researchers at the University of Bristol have discovered that this evolutionary adaptation laid the foundations for the incisor, canine and molar teeth that all mammals - including humans - possess today.

Shashajaia is one of the most primitive members of a group called the Sphenacodontoidea, which includes the famous sail-backed Dimetrodon, and mammal-like reptiles known as therapsids, which eventually evolved into mammals. It is remarkable for its age and anatomy, possessing a very unique set of teeth that set it apart from other synapsids – meaning the animal lineage that mammals belong to - of the time.

Dr Suresh Singh of the School of Earth Sciences explained: “The teeth show clear differentiation in shape between the front and back of the jaw, organized into distinct regions. This is the basic precursor of what mammals have today – incisors and canines up front, with molars in the back. This is the oldest record of such teeth in our evolutionary tree”.

China-wide study will boost understanding of fatal surgical complication

Older patients in hospitals across China took part in a major multi-center open-label randomized clinical trial that showed there was no difference in post-operative delirium in older people with a hip fracture, if they had a general anesthesia, or a regional anesthesia.

Post-operative delirium is a common, serious, neurological, complication where people have a sudden change in their brain functions after an operation. It is more common in older people, and leads to increased death, dementia, post-traumatic stress disorder, a longer length of hospital stay, extra nursing requirements and increased healthcare costs.

People with a hip fracture require an operation to fix the fracture which requires anesthesia - classified as general anesthesia, or regional anesthesia. A general anesthetic technique involves inducing sleep or loss of consciousness through inhaled or intravenous anesthetics. Regional anesthesia involves injecting local anesthetic inside the spine or around the nerves to prevent pain in the leg with the hip fracture.

It was commonly thought that one of the causes of delirium is a general anesthesia. Led by the University of Birmingham and Wenzhou Medical University Second Affiliated Hospital, this randomized trial was the first of its kind in China. 950 older adult took part, from hospitals in Wenzhou, Wuhan, Lishui, Ningbo, Nanchang, and Taizhou.

The trial was set up to provide clinical evidence with a robust methodology, to help medical professionals select appropriate anesthesia for older patients to try and reduce the development of delirium.

Crows keep special tools extra safe

Credit James St Clair

Just like humans, New Caledonian crows are particularly careful when handling their most valuable tools, according to a new study by researchers from the University of St Andrews and the Max Planck Institute of Animal Behavior.

The research, published in the leading scientific journal eLife today (21 December 2021), reveals that crows are more likely to store relatively complex and efficient foraging tools for future use than more basic tools.

New Caledonian crows are renowned for using different types of tools for extracting prey from tree holes and other hiding places. While they firmly hold their tools in the bill during foraging, they need to put them down to eat. This is when crows are at risk of losing their tools by accidentally dropping them or having them stolen by other crows.

In an earlier study, the researchers from the School of Biology at the University of St Andrews had shown that crows keep their tools safe when not needed, using one of two ‘safekeeping’ strategies – they either securely hold them trapped underfoot, or they temporarily insert them into a nearby hole or behind bark. But are crows more careful when handling particularly valuable tools.

New class of galac­tic nebulae disco­vered

Image: Discovery image of the nebula. For this image, 120 individual exposures had to be combined to obtain a total exposure time of 20 hours. The images were taken over several months from Brazil. Credit: Maicon Germiniani

An international team of astronomers led by Stefan Kimeswenger from the Department of Astro and Particle Physics, together with scientific amateurs, has identified a new class of galactic nebulae. This provides an important building block in the understanding of stellar evolution and shows the importance of international collaboration between university research and community science.

For the first time, scientists, starting from a discovery by scientific amateurs, have succeeded in providing evidence for a fully developed shell of a common-envelope-system (CE) – the phase of the common envelope of a binary star system. “Toward the end of their lives, normal stars inflate into red giant stars. Since a very large fraction of stars are in binary stars, this affects the evolution at the end of their lives. In close binary systems, the inflating outer part of a star merges as a common envelope around both stars. However, inside this gas envelope the cores of the two stars are practically undisturbed and follow their evolution like independent single stars,” explains astrophysicist Stefan Kimeswenger. The researchers have now published their results in the journal Astronomy & Astrophysics.

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