Pressure-Based Control Enables Tunable Singlet Fission Materials for Efficient Photoconversion

Applying hydrostatic pressure as an external stimulus, Tokyo Tech and Keio University researchers demonstrate a new way to regulate singlet fission (SF), a process in which two electrons are generated from a single photon, in chromophores, opening doors to the design of SF-based materials with enhanced (photo)energy conversion. Their method overrides the strict requirements that limit the molecular design of such materials by realizing an alternative control strategy.

Singlet fission (SF) is a process in which an organic chromophore (a molecule that absorbs light) in an excited singlet state transfers energy to a neighboring chromophore, resulting in two correlated triplet exciton pairs (pairs of bound electron-hole states, a "hole" signifying the absence of an electron) that decay to low energy triplet excitons. These excitons have long lifetimes and show efficient light emission, making SF promising for efficient light energy conversion.

However, the molecular design of SF-based materials is limited by the requirement that the energy of the excited singlet state must be at least equal to the energy of the two triplet states. One way to overcome this limit is by applying external stimuli, such as temperature or pressure, to manipulate the SF process.

Breakthrough on the way to the biological solar cell

Marc Nowaczyk which everted from the Ruhr University to the University of Rostock. The current works were partly made in Bochum.
Photo Credit: ITMZ University of Rostock

Researchers question the way photosynthesis works.

A research team from the University of Cambridge, the University of Rostock and the Ruhr University Bochum succeeded for the first time in obtaining electrons directly from the early stages of photosynthesis. This breakthrough questions the previous model for the basic functioning of photosynthesis and has the potential to revolutionize the development of solar cells based on biological catalysts. The research work was published in the renowned journal Nature from 22. Published March 2023.

Manufacture hydrogen with sunlight

Biological catalysts, so-called enzymes, have long since determined our everyday life. For example, they are used as additives in detergents, they refine food or are used in large-scale processes to produce medicines or raw materials for the chemical industry. Compared to chemical catalysts, they have the advantage that they only react with very specific raw materials and therefore produce very specific products. In addition, biological catalysts are never based on precious metals or other rare raw materials. "In nature, solutions have always been established that are not limited by the availability of raw materials," says Prof. Dr. Marc Nowaczyk, head of the chair for biochemistry at the University of Rostock and co-author of the study, who did part of the work at the Ruhr University Bochum as part of the graduate school Microbial Substrate Conversion, MiCon for short.

Use of melatonin linked to decreased self-harm in young people

There is currently a youth mental health crisis, and the risk of self-harm and suicide  is high.
Photo Credit: Vladislav Muslakov

Medical sleep treatment may reduce self-harm in young people with anxiety and depression, an observational study from Karolinska Institutet suggests. The risk of self-harm increased in the months preceding melatonin prescription and decreased thereafter, especially in girls. The study is published in The Journal of Child Psychology and Psychiatry.

Melatonin is a hormone that controls the sleep-wake cycle and is the most commonly prescribed drug for sleep disturbances in children and adolescents in Sweden. Melatonin use has dramatically increased in recent years, and it is available over the counter in Sweden since 2020.

“Given the established link between sleep problems, depression, and self-harm, we wanted to explore whether medical sleep treatment is associated with a lower rate of intentional self-harm in young people,” says Dr Sarah Bergen, docent at the Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, who led the study.

Clues to the cause of chronic gut pain

Professor Stuart Brierley
Photo Credit: Courtesy of Flinders University

New insights into chronic gut pain offer hope for improved treatments for irritable bowel syndrome and anxiety treatment.

A research team led by Flinders University Professor Stuart Brierley, based at the SA Health and Medical Research Institute, with Nobel Laureate Professor David Julius, Professor Holly Ingraham and Dr James Bayrer at the University of California San Francisco, has shown evidence of a specific pathway of cells and nerves linking the gut to the brain that may be responsible for the chronic gut pain.

Chronic gut pain is commonly experienced by 11% of the global population currently living with irritable bowel syndrome (IBS) and associated psychological conditions, including anxiety and depression.

Described in a new article in Nature, the team used genetic and pharmacologic tools in pre-clinical models to manipulate signals between gut epithelial cells and associated nerve fibers to determine how this pathway stimulates chronic gut pain and anxiety.

Researchers create artificial enzyme for fast detection of disease-related hormone in sweat

Photo Credit: Courtesy of Oregon State University

Researchers in the Oregon State University College of Engineering have developed a handheld sensor that tests perspiration for cortisol and provides results in eight minutes, a key advance in monitoring a hormone whose levels are a marker for many illnesses including various cancers.

Findings were published in the journal ACS Applied Materials & Interfaces. The material and sensing mechanism in the new device could be easily engineered to detect other specific hormones, the researchers say – for example, progesterone, a key marker for women’s reproductive health and pregnancy outcomes.

“We took inspiration from the natural enzymes used in blood glucose meters sold at pharmacies,” said Larry Cheng, associate professor of electrical engineering and computer science. "In glucose meters, specific enzymes are applied to an electrode, where they can capture and react with glucose molecules to generate an electrical signal for detection. However, finding natural enzymes for cortisol detection is not straightforward, and natural enzymes are prone to instability and have a short lifespan.

Volcanic Spring Water Will Help Researchers Make Plastic Electronics

Photo Credit: Courtesy of University of Tsukuba

Researchers from the University of Tsukuba have made electrically conductive polyaniline composites in mineral water. This work will increase the sustainability of manufacturing many consumer and industrial products

When you think of how to make electronic components, water probably doesn't top your list of raw materials. Nevertheless, in a study recently published in Journal of Water Chemistry and Technology, researchers from the University of Tsukuba have used volcanic spring water to help make the plastic that's an essential part of many modern technologies.

Plastic holds together the electronic components in many modern technologies. Polyaniline (PANI) is one of these plastics. Because millions of square meters of PANI are used every year for this and other purposes, there are clear benefits to making it in the most environmentally sustainable solvent possible. Many solvents can be used to make PANI—but most are rather toxic and incompatible with common mass-production device fabrication processes, such as inkjet printing.

Searching for life with space dust

Space dust. This piece of interplanetary dust is thought to be part of the early solar system and was found in our atmosphere, demonstrating lightweight particles could survive atmospheric entry as they do not generate much heat from friction.
Photo Credit: 2023 NASA CC-0

Following enormous collisions, such as asteroid impacts, some amount of material from an impacted world may be ejected into space. This material can travel vast distances and for extremely long periods of time. In theory this material could contain direct or indirect signs of life from the host world, such as fossils of microorganisms. And this material could be detectable by humans in the near future, or even now.

When you hear the words vacuum and dust in a sentence, you may groan at the thought of having to do the housework. But in astronomy, these words have different connotations. Vacuum of course refers to the void of space. Dust, however, means diffuse solid material floating through space. It can be an annoyance to some astronomers as it may hinder their views of some distant object. Or dust could be a useful tool to help other astronomers learn about something distant without having to leave the safety of our own planet. Professor Tomonori Totani from the University of Tokyo’s Department of Astronomy has an idea for space dust that might sound like science fiction but actually warrants serious consideration.

Climate change affects greenhouse gas emissions from stream networks

Photo Credit: Mitchell Kmetz

Natural greenhouse gas emissions from streams and lakes are strongly linked to water discharge and temperature according to a new study led by Linköping University, Sweden. This knowledge is necessary to assess how man-made climate change is altering greenhouse emissions from natural landscapes and has large implications for climate change mitigation measures.

“The study is a big step forward towards increased understanding of the greenhouse gas fluxes in stream networks, providing potential to predict future fluxes", says David Bastviken, professor at Thematic Studies Environmental Change. Charlotte Perhammar

“The use of agriculture and forestry as carbon sinks is debated at the moment and the question is how effective such carbon sinks are for mitigating climate change. Our new study shows that with increased precipitation, a larger amount of carbon may be washed into streams and lakes and an increased share of this carbon also ends up in the atmosphere. Hence, landscape carbon sinks may become less effective in the future,” says David Bastviken, professor at the Department of Thematic Studies Environmental Change at Linköping University.

Tackling counterfeit seeds with “unclonable” labels

As a way to reduce seed counterfeiting, MIT researchers developed a silk-based tag that, when applied to seeds, provides a unique code that cannot be duplicated.
Photo Credit: Photograph courtesy of the researchers. Edited by Jose-Luis Olivares, MIT
(CC BY-NC-ND 3.0)

Average crop yields in Africa are consistently far below those expected, and one significant reason is the prevalence of counterfeit seeds whose germination rates are far lower than those of the genuine ones. The World Bank estimates that as much as half of all seeds sold in some African countries are fake, which could help to account for crop production that is far below potential.

There have been many attempts to prevent this counterfeiting through tracking labels, but none have proved effective; among other issues, such labels have been vulnerable to hacking because of the deterministic nature of their encoding systems. But now, a team of MIT researchers has come up with a kind of tiny, biodegradable tag that can be applied directly to the seeds themselves, and that provides a unique randomly created code that cannot be duplicated.

The new system, which uses minuscule dots of silk-based material, each containing a unique combination of different chemical signatures, is described today in the journal Science Advances in a paper by MIT’s dean of engineering Anantha Chandrakasan, professor of civil and environmental engineering Benedetto Marelli, postdoc Hui Sun, and graduate student Saurav Maji.

New UBC water treatment zaps ‘forever chemicals’ for good

 

UBC researchers devised a unique adsorbing material that is capable of capturing all the PFAS present in the water supply.
Photo Credit: Mohseni lab

Engineers at the University of British Columbia have developed a new water treatment that removes “forever chemicals” from drinking water safely, efficiently – and for good.

“Think Brita filter, but a thousand times better,” says UBC chemical and biological engineering professor Dr. Madjid Mohseni, who developed the technology.

Forever chemicals, formally known as PFAS (per-and polyfluoroalkyl substances) are a large group of substances that make certain products non-stick or stain-resistant. There are more than 4,700 PFAS in use, mostly in raingear, non-stick cookware, stain repellents and firefighting foam. Research links these chemicals to a wide range of health problems including hormonal disruption, cardiovascular disease, developmental delays and cancer.

To remove PFAS from drinking water, Dr. Mohseni and his team devised a unique absorbing material that is capable of trapping and holding all the PFAS present in the water supply.

The PFAS are then destroyed using special electrochemical and photochemical techniques, also developed at the Mohseni lab and described in part in a paper published recently in Chemosphere.