Newly discovered virus can kill resistant bacteria

Peer-Reviewed Publication

UNIVERSITY OF SOUTHERN DENMARK

- We have found five new species that we believe are unknown to science, said associate professor Clare Kirkpatrick, who studies bacterial stress-response at the Department of Biochemistry and Molecular Biology at University of Southern Denmark.

The somewhat surprising discovery was made during the coronavirus pandemic, when some of Kirkpatrick's students could not carry out their normal microbe studies in the laboratory and  therefore went on field trips to local creeks to see if they had any interesting microbes to offer. 

The fact that viruses exist in nature is not surprising, as they are the world's most widespread organism. They are everywhere and part of all kinds of microbial cycles and ecosystems, but the fact that five potentially new species have appeared in local creeks, did surprise Clare Kirkpatrick. 

While four of the five have not yet had their genome mapped in a genome sequencing, one species has now been fully sequenced, scientifically described, named and published in Microbiology Resource Announcements. The name is Fyn8. 

Many viruses are so-called bacteriophages (or phages), meaning that they kill bacteria, and Fyn8 is no exception. It can attack and kill the bacteria Pseudomonas aeruginosa. 

Pseudomonas aeruginosa is a bacterium found naturally in soil and water. It is normally harmless towards healthy people, but like many other bacteria it has developed resistance to antibiotics and is found in hospitals. 

For example, patients with wounds (like burn patients) and ventilator patients are at risk of getting an infection that cannot be fought with antibiotics. 

The researchers have no doubt that Fyn8 can effectively kill Pseudomonas aeruginosa: 

- We could see it with the naked eye: Clear holes appeared in the layer of Pseudomonas aeruginosa bacteria in our petri dishes, where Fyn8 had infected the bacterial cells, killed them, multiplied and proceeded to attack the next. 

Considering that the world is facing a resistance crisis, where more people will die from an infection with resistant bacteria than from cancer, the new finding is of course interesting and raises the question; Can phages help us in the fight against resistant bacteria? 

Research in this field has been uncommon until recently, both in academic research institutions and in pharmaceutical companies. In the past and in other parts of the world however, there has been some research, and phages have also been used to treat infections in Eastern European countries in particular. 

The phages were discovered at the beginning of the 20th century by researchers who had their bacterial cultures destroyed by virus infections.

The benefits of that discovery were obvious, but antibiotics, not phages, became the most widespread cure against bacterial infections. 

One reason was perhaps that antibiotics were easy to produce and easy to use, while the phages were difficult to isolate and give to patients.  

Another reason was probably also that an antibiotic dose could kill many different bacteria, while a phage only matches with a single bacterial species. 

- But today it is relatively easy to make precision medicine for the individual patient. First you find out what exact bacteria a patient is infected with - and then you can treat the patient with exactly the phage that will kill the bacteria, explained Clare Kirkpatrick.  

She adds that this strategy works even on bacteria which are resistant to all known antibiotics.  

Time will tell whether there are more new virus species in the local creeks near University of Southern Denmark campus, but it is quite probable, Clare Kirkpatrick believes: 

- Many, many more are waiting to be discovered. 

 

Bacteria killing viruses in nature: Viruses that infect and kill bacteria are called bacteriophages. An estimated 10,000,000,000,000,000,000,000,000,000,000 (1031) of them exist in nature. That is roughly one trillion bacteriophages for every grain of sand in the world.  

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JOURNAL

Microbiology Resource Announcements

DOI

10.1128/mra.00004-23 

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

People

ARTICLE TITLE

Complete Genome Sequence of the Lysogenic Pseudomonas Bacteriophage Fyn8

ARTICLE PUBLICATION DATE

13-Feb-2023

SEE

https://plawiuk.blogspot.com/search?q=PHAGES

 https://plawiuk.blogspot.com/search?q=BIOPHAGES

 https://plawiuk.blogspot.com/search?q=PHAGE

 https://plawiuk.blogspot.com/search?q=BACTERIOPHAGE

Can the Kunming-Montreal Global Biodiversity Framework fulfil its transformative potential?

Peer-Reviewed Publication

FUTURE EARTH

 

IMAGE: FIGURE 1. THE TWENTY THREE TARGETS OF THE GLOBAL BIODIVERSITY FRAMEWORK ARE SPREAD ACROSS MOST DOMAINS ACROSS THE SUSTAINABLE DEVELOPMENT GOALS. THESE INCLUDE CONSERVATION ACTIONS THAT ADDRESS DIRECT DRIVERS OF BIODIVERSITY LOSS (BOTTOM LAYER, ‘NATURE’), AND ACTIONS THAT ADDRESS INDIRECT DRIVERS OF BIODIVERSITY LOSS, INCLUDING ON ECONOMIC GOALS (SECOND LAYER, ‘ECONOMY’), SOCIAL GOALS (THIRD LAYER, ‘SOCIETY’) AND THE MEANS TO ACHIEVE SUCCESS (TOP LAYER, ’MEANS OF IMPLEMENTATION’). view more 

CREDIT: N/A

MOMBASA, Kenya – With the goals and targets of the Kunming-Montreal global biodiversity framework now set, attention turns to its potential for implementation and achieving its 2050 vision of living in harmony with nature.

In a peer-reviewed commentary published in the journal One Earth on 17 February 2023, marine and sustainability scientist Dr. David Obura of CORDIO East Africa and the Earth Commission dissects the scope of the agreement, and its potential to mark a turning point in international policy. The commentary argues that the agreement contains all the ingredients for success, i.e. to halt and reverse biodiversity loss and achieve sustainability for all, but to do this countries and actors will need to overcome some particularly challenging and entrenched North-South divides. Without accountability for historic and current trends, nor full commitments to close the funding gap for proposed actions, the agreement could risk the same failed fate as the Aichi Targets of 2010-2020.

The commentary reflects on experiences surrounding the adoption of the framework at COP 15, and in the preceding 3.5 years of layered negotiations. Obura concludes that in the coming years the global community needs to transform and fully adopt equity principles that remedy centuries of extraction and capital accumulation by imperialist-colonial-capitalist economies. Dr. Obura identifies three persisting challenges that if not addressed will undermine success of the new framework:

• The drivers of biodiversity decline must be brought within planetary boundaries as a prerequisite for success;
• Actors must fully finance the framework. This means transforming away from the imperial-colonial-capitalist tradition that dominates today and externalizes most biodiversity impacts, to circular sustainability-oriented principles that fully internalize all impacts into the costs of doing business.
• Putting relationships between Global North and Global South countries on a fully equitable footing, and acting to assure the rights and agency of Indigenous Peoples and Local Communities in conservation.

“Far from this being a radical take on the Kunming-Montreal Global Biodiversity Framework, all the elements needed to overcome these challenges are contained within its text,” said the author, Dr. David Obura, “so the test will be if countries and leading actors fully adopt these and transform, or pay lip service to them and stay within their comfort zones, just with a bit more money on the table, and with strings attached."

“It boils down to the Global North acknowledging the just needs of the Global South and at the same time realizing the funding required is not aid or charity, it is unpaid dues for unjust historic appropriation of biodiversity, resulting from their economic growth to date. The answers for the future are to specifically account for damage from the past.”

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JOURNAL

One Earth

DOI

10.1016/j.oneear.2023.01.013 

METHOD OF RESEARCH

Commentary/editorial

ARTICLE TITLE

The Kunming-Montreal Global Biodiversity Framework: Business as usual or a turning point?

ARTICLE PUBLICATION DATE

17-Feb-2023

Food quality matters for southern resident killer whales, UBC study states

For southern resident killer whales, the fattier the prey the better.

Peer-Reviewed Publication

UNIVERSITY OF BRITISH COLUMBIA

 

IMAGE: LOW LIPID CHINOOK ARE A PROBLEM FOR SRKW view more 

CREDIT: INFOGRAPHIC © AYODELE OLOKO AND BENIA NOWAK

Not all Chinook salmon are created equal, and this has a major impact on the energetics for southern resident killer whales. A recent study quantified the lipid content in Fraser River Chinook salmon – the southern resident’s preferred meal – and found that spring-run Chinook salmon, the earliest to arrive to the Salish Sea are lipid-rich and energy dense; a critical factor for the killer whales who prey on them. Fraser River Chinook salmon that come later in the season have lower energy density.

“This research helps us quantify the energetic requirements of the southern residents,” said Jacob Lerner, lead author of the study and a doctoral student in the Pelagic Ecosystems Lab at the Institute for the Oceans and Fisheries. “For example, if the southern residents ate just low-lipid salmon, they would have to eat around 80,000 more Chinook salmon every year than if they just ate high-lipid salmon.”

Southern resident killer whales are an iconic species in British Columbia’s Salish Sea and down the northeastern Pacific coast. With black and white markings, these marine mammals can weigh up to 12,000 pounds and be up to 26 feet long. They are fierce, social creatures that live and hunt in family group pods. And, sadly, there are only 73 left in the world.

Critically endangered by a number of anthropogenic factors, including noise pollution and high levels of water contaminants, their decline is mostly based on the limited availability of their preferred prey – Chinook salmon. However, there are many distinct populations of Chinook salmon available throughout the year, some with stock-specific differences in energy density, and not all in decline.

“We began with an initial hypothesis that these salmon were all created equal, that they all have the same value to resident killer whales. And we quickly realized that this is not true at all,” said Lerner. “They all have different levels of lipid content.”

Quantifying that lipid content is important as it directly relates to the caloric value of a salmon, assigning its value as prey. Specific estimates of lipid content for Chinook populations with different distributions, or run-timings, could be used to inform trends in killer whale populations, properly time fisheries closures, or even decide which hatcheries to augment to increase high quality food availability for southern residents, Lerner said.

This is particularly important as southern resident killer whales are a migratory species and often spend their winter months elsewhere. When they return to the Salish Sea for the spring and summer, their arrival often coincides with the arrival of the spring-run Fraser River Chinook salmon.

“Southern resident killer whales used to come here earlier in the spring season when they could eat early migrating Chinook salmon,” said Brian Hunt, associate professor in the Institute for the Oceans and Fisheries. “Those early Chinook were very energy dense as they need to fuel their long freshwater migration back to their spawning grounds, but those stocks have been declining. With the whales coming later, they mainly have access to Chinook from the lower Fraser. These fish don’t migrate very far, and have lower energy density.”

As a major source of prey for southern residents, estimates of lipid content from Fraser bound Chinook salmon may be one of the keys to helping both threatened species. “We identified a spectrum of high, medium and low-lipid Chinook populations from the Fraser that can be used to better inform energetics models and manage both species,” Lerner stated, “We also identified life history parameters for the salmon to predict where on this spectrum they may fall.”

Though the study has quantified lipid content in Fraser River Chinook, and shown new light on its life history drivers, there is still little information on how ocean conditions influence this energy accumulation.

“We plan to keep monitoring Fraser Chinook salmon fat content,” said Hunt. “And one of questions we want to answer is how changing ocean conditions might be affecting their energy accumulation. Our concern is that ocean warming and food web shifts in the North Pacific Ocean are leading to lower energy accumulation in Chinook salmon. This will have implications for both the Chinook themselves – will they have enough energy for return migration and spawning? – and the killers whales that depend on them.”

‘Seasonal variation in the lipid content of Fraser River Chinook Salmon (Oncorhynchus tshawytscha) and its implications for Southern Resident Killer Whale (Orcinus orca) prey quality‘ was published in Scientific Reports.

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JOURNAL

Scientific Reports

DOI

10.1038/s41598-023-28321-9 

METHOD OF RESEARCH

Meta-analysis

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

Seasonal variation in the lipid content of Fraser River Chinook Salmon (Oncorhynchus tshawytscha) and its implications for Southern Resident Killer Whale (Orcinus orca) prey quality

How the Mongolian gerbil may help speed recovery of a rare inner ear problem

Rutgers scientists develop testing model to enhance understanding of a condition known as “third window syndrome”

Peer-Reviewed Publication

RUTGERS UNIVERSITY

To patients of P. Ashley Wackym, a surgical otologist-neurotologist at Rutgers Robert Wood Johnson Medical School, a diagnosis of superior semicircular canal dehiscence (SSCD) can feel like a death sentence.

 

SSCD, a type of “third window syndrome,” is caused by an abnormal third mobile window of the inner ear. Normally humans have two of these windows. When a third “window” is present – at birth, after trauma or for reasons that remain unclear – patients can suffer sound-induced dizziness, hearing internal sounds unusually well (one-third can hear their eyes move or blink), and chronic headaches.

 

Patients can also suffer cognitive dysfunction – such as impaired memory, poor concentration, spatial disorientation, slurred speech, out-of-body experiences and crippling anxiety.

 

“If you could just blow my head off, I’d let you,” one patient said she told her husband after receiving a diagnosis of SSCD. Vertigo, nausea, confusion and other symptoms of the rare inner ear problem had made everyday tasks – from shopping to listening to music – unbearable. “I cannot live like this,” she said.

 

Wackym, Todd Mowery and other colleagues in the Department of Otolaryngology – Head and Neck Surgery are working to speed the recovery of patients like this one, and a Mongolian gerbil with an ear structure like humans could help eventually help researchers better understand the cognitive challenges and facilitate recovery.

 

Their findings are published in the neuro-otology section of the journal Frontiers in Neurology.

 

“We don’t know what part of the brain is impacted by this disorder,” said Wackym. “That's where the animal model comes in. With this model we might be able to understand the nervous system pathways affected by SSCD and develop interventions to prevent this dysfunction or accelerate recovery.”

 

As much as two percent of the U.S. population has SSCD, which was first medically identified in 1998. “While surgery can plug the third hole, based upon neuropsychology studies in these patients, full cognitive recovery can take between three and 18 months,” Wackym said.

 

To develop the animal testing model, 36 adult Mongolian gerbils were randomly divided into two groups, which received either a small (one millimeter) or large (two millimeter) semicircular canal fenestration in their inner ear. This procedure created an artificial third window.

 

The researchers then studied how the animals responded to pressure and sound stimulation. They found that the large window resulted in similar electrophysiologic findings as observed in human patients with SSCD.

 

They also discovered the bony holes created in the animal’s inner ear healed spontaneously, with all hearing and balance functioning returning to baseline. “This will enable future studies to test SSCD conditions before, during and after recovery — findings that could be applied to human patients,” Wackym said.

 

“If we knew what was impacted and what was involved with the central neuroplasticity of SSCD, we could develop interventions that might speed up the human-recovery process,” he said. “As the first successful animal model for SSCD, this tool will help neuroscientists better understand the anatomy and pathology of SSCD cognitive dysfunction.”

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JOURNAL

Frontiers in Neurology

DOI

10.3389/fneur.2022.1035478 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

New model of superior semicircular canal dehiscence with reversible diagnostic findings characteristic of patients with the disorder

WAIT, WHAT?!

Study finds watching TV is good for the planet

Peer-Reviewed Publication

OXFORD UNIVERSITY PRESS USA

A new paper in Annals of Botany, published by Oxford University Press, indicates that watching nature documentaries makes people more interested in plants, potentially provoking an involvement in botany and ecology.

Some 40% of plant species are under threat of extinction. Plants that are not directly useful to humans are particularly vulnerable. People often do not recognize how important many plants are due to a cognitive bias sometimes called “plant blindness” or “plant awareness disparity.” While humans are generally concerned with endangered animals, threats to plants are harder to recognize and address. In the United States, for example, plants receive less than 4% of federal funding for endangered species, despite comprising 57% of the endangered species list.

Researchers here noted that in the past several natural history productions, including Planet Earth II, Blue Planet II, Seven Worlds, and One Planet, made viewers much more aware of the animals on the shows. While scientists cannot draw a clear link between such TV shows and conservation efforts, nature documentaries provide a direct way to reach mass audiences and engage them.

Here, the researchers investigated whether nature documentaries can promote plant awareness, which may ultimately increase audience engagement with plant conservation programs. They focused on Green Planet, a 2022 BBC documentary narrated by Sir David Attenborough. The show, watched by nearly 5 million people in the United Kingdom, featured a diversity of plant species, highlighting vegetation from tropical rainforests, aquatic environments, seasonal lands, deserts, and urban spaces. The program also addressed environmental concerns directly, examining the dangers of invasive monocultures and deforestation.

The researchers measured whether Green Planet drove interest in the plants by exploring people’s online behavior around the time of the broadcast. First, they noted the species that appeared on the show and the time each one appeared on-screen. Then they extracted Google Trends and Wikipedia page hits for those same species before and after the episodes of the documentary aired.

The researchers here found a substantial effect of Green Planet on viewers’ awareness and interest in the portrayed plant species. Some 28.1% of search terms representing plants mentioned in the BBC documentary had peak popularity in the UK, measured using Google Trends, the week after the broadcast of the relevant episode. Wikipedia data showed this as well. Almost a third (31.3%) of the Wikipedia pages related to plants mentioned in Green Planet showed increased visits the week after the broadcast. The investigators also note that people were more likely to do online searches for plants that enjoyed more screen time on Green Planet.

“I think that increasing public awareness of plants is essential and fascinating," said the paper’s lead author, Joanna Kacprzyk. “In this study, we show that nature documentaries can increase plant awareness among the audience. Our results also suggest that the viewers found certain plant species particularly captivating. These plants could be used for promoting plant conservation efforts and counteracting the alarming loss of plant biodiversity.“

The paper, “Making a greener planet: nature documentaries promote plant awareness,” is available (at midnight on February 16th) at: https://academic.oup.com/aob/article-lookup/doi/10.1093/aob/mcac149.

Direct correspondence to: 
Joanna Kacprzyk
School of Biology and Environmental Sciences
University College Dublin
Dublin 4, IRELAND
joanna.kacprzyk@ucd.ie

To request a copy of the study, please contact:
Daniel Luzer 
daniel.luzer@oup.com

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JOURNAL

Annals of Botany

DOI

10.1093/aob/mcac149 

METHOD OF RESEARCH

Content analysis

SUBJECT OF RESEARCH

People

ARTICLE TITLE

Making a greener planet: nature documentaries promote plant awareness

ARTICLE PUBLICATION DATE

16-Feb-2023

Carolina researchers develop greener alternative to fossil fuels by producing hydrogen from water and light

Peer-Reviewed Publication

UNIVERSITY OF NORTH CAROLINA AT CHAPEL HILL

 

IMAGE: FROM LEFT TO RIGHT: JAMES CAHOON AND TAYLOR TEITSWORTH view more 

CREDIT: STEVE EXUM

Researchers at the University of North Carolina at Chapel Hill Department of Chemistry have engineered silicon nanowires that can convert sunlight into electricity by splitting water into oxygen and hydrogen gas, a greener alternative to fossil fuels.

Fifty years ago, scientists first demonstrated that liquid water can be split into oxygen and hydrogen gas using electricity produced by illuminating a semiconductor electrode. Although hydrogen generated using solar power is a promising form of clean energy, low efficiencies and high costs have hindered the introduction of commercial solar-powered hydrogen plants. 

An economic feasibility analysis suggests that using a slurry of electrodes made from nanoparticles instead of a rigid solar panel design could substantially lower costs, making solar-produced hydrogen competitive with fossil fuels. However, most existing particle-based light-activated catalysts, also referred to as photocatalysts, can absorb only ultraviolet radiation, limiting their energy-conversion efficiency under solar illumination.

James Cahoon, Ph.D., Hyde Family Foundation Professor of Chemistry in UNC-Chapel Hill’s College of Arts and Sciences, and his colleagues in the department have been working on the chemical synthesis of semiconductor nanomaterials with unique physical properties that can enable a range of technologies, from solar cells to solid-state memory. Cahoon serves as the corresponding author of the findings published Feb. 9 in Nature. 

Cahoon and his team designed new silicon nanowires to have multiple solar cells along their axis so that they could produce the power needed to split water. 

“This design is unprecedented in previous reactor designs and allows silicon to be used for the first time in a PSR,” explained Taylor Teitsworth, a postdoctoral research associate in Cahoon's lab.

Silicon absorbs both visible and infrared light. It has historically been a top choice for solar cells, also referred to as photovoltaic cells and semiconductors, owing to this and other properties – including its abundance, low toxicity and stability. With its electronic properties, the only way to drive water splitting wirelessly with silicon particles is to encode multiple photovoltaic cells in each particle. This can be achieved by generating particles that contain multiple interfaces, called junctions, between two different forms of silicon — p-type and n-type semiconductors.

Previously, Cahoon’s research focused on a bottom-up synthesis and spatially controlled modulation of silicone with boron for p-type nanowires and with phosphorus for n-type nanowires to impart desirable geometries and functionalities.

“We used this approach to create a new class of water-splitting multijunction nanoparticles. These combine the material and economic advantages of silicon with the photonic advantages of nanowires that have a diameter smaller than the wavelength of absorbed light,” said Cahoon. “Owing to the inherent asymmetry of the wire junctions, we were able to use a light-driven electrochemical method to deposit the co-catalysts selectively onto the ends of the wires to enable water splitting.”

The research was supported by grant CBET-1914711 from the National Science Foundation (NSF) with foundational work supported by the Alliance for Molecular Photoelectrode Design for Solar Fuels, an Energy Frontier Research Center funded by the US Department of Energy, Office of Science, Office of Basic Energy Sciences under award no. DE-SC0001011. 

Device fabrication and electron microscopy imaging and analysis were performed in part at the Chapel Hill Analytical and Nanofabrication Laboratory, a member of the North Carolina Research Triangle Nanotechnology Network, which is supported by grant ECCS-2025064 from the NSF as part of the National Nanotechnology Coordinated Infrastructure. The Research Computing group at the University of North Carolina at Chapel Hill also provided computational resources for optical simulations.  

The research received additional support from the NSF by grant CHE-1848278 for s-SNOM characterization and through various individual graduate research fellowships.

Learn more at http://cahoon.chem.unc.edu. 

JOURNAL

Nature

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Designer silicon nanowires produce hydrogen from water and light

This ‘Harry Potter’ light sensor achieves magically high efficiency of 200 per cent

Using green light and a double-layered cell, Riccardo Ollearo of the Eindhoven University of Technology has come up with a photodiode that has sensitivity that many can only dream of.

Peer-Reviewed Publication

EINDHOVEN UNIVERSITY OF TECHNOLOGY

Using green light and a double-layered cell, PhD researcher Riccardo Ollearo has come up with a photodiode that has sensitivity that many can only dream of.

Solar panels with multiple stacked cells are currently breaking records. Remarkably, a team of researchers from Eindhoven University of Technology and TNO at Holst Centre have now managed to make photodiodes - based on a similar technology - with a photoelectron yield of more than 200 percent. You would think that efficiencies of more than 100 percent are only possible using alchemy and other Harry Potter-like wizardry. But it can be done. The answer lies in the magical world of quantum efficiency and stacked solar cells.

René Janssen, professor at the Eindhoven University of Technology and co-author of a new Science Advances paper, explains. “I know, this sound incredible. But, we’re not talking about normal energy efficiency here. What counts in the world of photodiodes is quantum efficiency. Instead of the total amount of solar energy, it counts the number of photons that the diode converts into electrons.

I always compare it to the days when we still had guilders and lira. If a tourist from the Netherlands received only 100 lira for their 100 guilders during their holiday in Italy, they might have felt a bit shortchanged. But because in quantum terms, every guilder counts as one lira, they still achieved an efficiency of 100 per cent. This also holds for photodiodes: the better the better the diode is able to detect weak light signals, the higher its efficiency.”

Dark current
Photodiodes are light-sensitive semiconductor devices that produce a current when they absorb photons from a light source. They are used as sensors in a variety of applications, including medical purposes, wearable monitoring, light communication, surveillance systems, and machine vision. In all these domains, high sensitivity is key. 

For a photodiode to work correctly, it has to meet two conditions. Firstly, it should minimize the current that is generated in the absence of light, the so-called dark current. The less dark current, the more sensitive the diode. Secondly, it should be able to distinguish the level of background light (the ‘noise’) from the relevant infrared light. Unfortunately, these two things usually do not go together, on the contrary.

Tandem
Four years ago, Riccardo Ollearo, one of Janssen’s PhD students and lead author of the paper, set about solving this conundrum. In his research he joined forces with the photodetector team working at Holst Centre, a research institute specialized in wireless and printed sensor technologies, Ollearo built a so-called tandem diode, a device that combines both perovskite and organic PV cells.

Combining these two layers – a technique also increasingly used in state-of-the-art solar cells – he was able to optimize both conditions, reaching an efficiency of 70 per cent.

 “Impressive, but not enough”, says the ambitious young researcher from Italy. “I decided to see if I could increase the efficiency even further with the help of green light. I knew from earlier research that Illuminating solar cells with additional light can modify their quantum efficiency, and in some cases enhance it. To my surprise, this worked even better than expected in improving the photodiode sensitivity. We were able to increase the efficiency for near-infrared light to over 200 per cent!”

Mystery
Up this point, the researchers still don’t know exactly how this works, although they’ve come up with a theory that might explain the effect.

“We think that the additional green light leads to a build-up of electrons in the perovskite layer. This acts as a reservoir of charges that is released when infrared photons are absorbed in the organic layer”, says Ollearo. “In other words, every infrared photon that gets through and is converted in an electron, gets company from a bonus electron, leading to an efficiency of 200 per cent or more. Think of it as getting two lira for your guilder, instead of one!”

Putting the diode to the test
The researcher tested the photodiode, which is hundred times as thin as a sheet of newsprint, and suitable for use in flexible devices,, in the lab. “We wanted to see whether the device could pick up subtle signals, such as the heart or respiration rate of a human being in an environment with realistic background light. We opted for an indoor scenario, during a sunny day with the curtains partially closed. And it worked!”

Holding the device at 130 cm from a finger, the researchers were able to detect minute changes in the amount of infrared light that was reflected back into the diode. These changes turn out to be a correct indication of changes in the blood pressure in a person’s veins, which in turn indicate heart rate. When pointing the device at the person’s chest, they were able to measure the respiration rate from light movements in the thorax (see image)”.

Future

With the publication of the paper in Science Advances, Ollearo’s work is all but finished. He will defend his thesis research on April 21. So, does the research stop there?

“No, certainly not. We want to see if we can further improve the device, for instance by making it quicker”, says Janssen. “We also want to explore whether we can clinically test the device, for instance in collaboration with the FORSEE project.”

The FORSEE project, led by TU/e researcher Sveta Zinger and in collaboration with the Catharina Hospital in Eindhoven, is developing an intelligent camera that can observe a patient’s heart and respiration rates.

Let’s hope the researchers at TU/e and TNO continue to prove that you don’t need to be a Harry Potter to achieve amazing feats of science!

More information

Riccardo Ollearo, René Janssen, Gerwin Gelinck et al. Vitality surveillance at distance using thin-film tandem-like narrowband near-infrared 2 photodiodes with light-enhanced responsivity, Science Advances

 

In the left image we see the set-up in which the new tandem photodiode can be used to monitor the heart and respiration rates of a person. The right images show the detected heart and respiration signals recorded with the photodiode at a distance of 130 cm.

CREDIT

TU/e | Riccardo Ollearo

Holding the photodiode device at 130 cm from his finger, researcher Riccardo Ollearo was able to detect minute changes in the amount of infrared light that was reflected back into the diode. These changes turn out to be a correct indication of a person’s heart rate.

CREDIT

TU/e | Bart van Overbeeke

JOURNAL

Science Advances

DOI

10.1126/sciadv.adf9861 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Vitality surveillance at distance using thin-film tandem-like narrowband near-infrared photodiodes with light-enhanced responsivity

ARTICLE PUBLICATION DATE

17-Feb-2023

Tame heat with pressure

Peer-Reviewed Publication

CHINESE ACADEMY OF SCIENCES HEADQUARTERS

 

IMAGE: BAROCALORIC THERMAL BATTERIES: CONCEPT AND REALIZATION. view more 

CREDIT: INSTITUTE OF METAL RESEARCH

A Chinese research team has developed a new concept for extracting thermal energy from low-temperature waste heat sources and reusing it on demand simply by controlling the pressure.

Heat production accounts for more than 50% of the world's final energy consumption and analysis of waste heat potential shows that 72% of the world's primary energy consumption is lost after conversion, mainly in the form of heat. It is also responsible for more than 30% of global greenhouse gas emissions.

Against this background, researchers led by Prof. LI Bing from the Institute of Metal Research of the Chinese Academy of Sciences have proposed and realized a new concept—barocaloric thermal batteries based on the unique inverse barocaloric effect.

The study was published in Science Advances.

An inverse barocaloric effect is characterized by a pressure-induced endothermic response, in sharp contrast to a normal barocaloric effect where pressurization leads to an exothermic response. "A barocaloric thermal battery cycle consists of three steps, including thermal charging upon pressurization, storage with pressure, and thermal discharging upon depressurization," said Prof. LI, corresponding author of the study.

The barocaloric thermal battery was materialized in ammonium thiocyanate (NH4SCN). Discharge was manifested as the heat of 43 J g-1 or a temperature rise of about 15 K. The heat released was 11 times greater than the mechanical energy input.

To understand the physical origin of the unique inverse barocaloric effect, the working material NH4SCN has been well characterized using synchrotron X-ray and neutron scattering techniques. It undergoes a crystal structural phase transition from a monoclinic to an orthorhombic phase at 363 K, accompanied by a volumetric negative thermal expansion of ~5% and entropy changes of about 128 J kg-1 K-1.

This transition is easily driven by pressure as low as 40 MPa, and it is the first inverse barocaloric system with entropy changes greater than 100 J kg-1K-1. Pressure-dependent neutron scattering and molecular dynamics simulations showed that the transverse vibrations of SCN¯ anions are enhanced by pressure and the hydrogen bonds that form the long-range order are then weakened.

As a result, the system becomes disordered in response to external pressure and thus the material absorbs heat from the environment.

As an emerging solution for manipulating heat, barocaloric thermal batteries are expected to play an active role in a variety of applications such as low-temperature industrial waste heat harvesting and reuse, solid-state refrigeration heat transfer systems, smart grids, and residential heat management.

This study was supported by CAS, the Ministry of Science and Technology of China, and the National Natural Science Foundation of China.

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JOURNAL

Science Advances

DOI

10.1126/sciadv.add0374 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Thermal batteries based on inverse barocaloric effects

ARTICLE PUBLICATION DATE

17-Feb-2023