Tech

There are different solutions for storing electrical energy: Lithium-based electrochemical batteries, for example, store large amounts of energy, but require long charging times. Supercapacitors, on the other hand, are able to absorb or release electrical energy extremely quickly - but store much less electrical energy.

Pseudocapacitors MXene

A further option is on the horizon since 2011: A new class of 2D materials that could store enormous amounts of charge was discovered at Drexel University, USA. These were so-called MXenes, Ti3C2Tx nanosheets that form a two-dimensional network together, similar to graphene. While titanium (Ti) and carbon (C) are elements, Tx describes different chemical groups that seal the surface, for example OH-groups. MXenes are highly conductive materials with hydrophilic surfaces and can form dispersions resembling black ink, composed of stacked layered particles in water.

Ti3C2Tx MXene can store as much energy as batteries, but can be charged or discharged within tens of seconds. While similarly fast (or faster) supercapacitors absorb their energy by electrostatic adsorption of electrical charges, the energy is stored in chemical bonds at the surface of MXenes. Energy storage is therefore much more efficient.

New insights into chemistry by soft X-ray methods

In cooperation with the group of Yuri Gogotsi at Drexel University, the HZB scientists Dr. Tristan Petit and Ameer Al-Temimy have now for the first time used soft X?ray absorption spectroscopy to investigate MXene samples at two experimental stations LiXEdrom and X-PEEM at BESSY II. With these methods, the chemical environment of MXene surface groups was analyzed over individual MXene flakes in vacuum but also directly in water environment. They found dramatic differences between pristine MXenes and MXenes between which urea molecules were intercalated.

Urea increases the capacity

The presence of urea molecules also significantly changes the electrochemical properties of MXenes. The area capacity increased to 1100 mF/cm2, which is 56 percent higher than pristineTi3C2Tx electrodes prepared similarly. The XAS analyses at BESSY II showed that surface chemistry is changed by the presence of the urea molecules. "We could also observe the oxidation state of the Ti atoms on the Ti3C2Tx MXene surfaces by using X-PEEM. This oxidation state was higher with the presence of urea which may facilitate to store more energy" says Ameer Al-Temimy, who performed the measurements as part of his doctorate.

Graphene Flagship researchers at the University of Rome Tor Vergata, the Italian Institute of Technology (IIT) and its spin-off, Graphene Flagship Associate Member BeDimensional, in cooperation with ENEA have successfully combined graphene with tandem perovskite-silicon solar cells to achieve efficiencies of up to 26.3%. Moreover, they envisioned a new manufacturing method that, thanks to the versatility of graphene, allows to reduce production costs and could lead to the production of large-area solar panels. Graphene-based tandem solar cells almost double the efficiency of pure silicon.

Laws of physics limit the maximum efficiency of silicon solar cells to 32%. For that reason, scientists have spent decades trying to come up with other alternatives, such as III-V and perovskites. However, the latter present several manufacturing challenges, and scaling up the production of solar panels is a key step towards success. With 'tandem cells', scientists had previously combined the advantages of both silicon and perovskites - however stability, efficiency and large-scale manufacturing still seemed like a far-fledged dream.

But then graphene came into play - and it could be a game changer. Graphene Flagship researchers identified its potential for energy harvesting, and in fact have dedicated two different industry-oriented 'Spearhead Projects' to dig into the possibilities of graphene-based solar cells. This new paper published in Joule - a reference journal in the field of energy research - is yet another proof that graphene and related layered materials will enable the commercialisation of more efficient and cost-effective large area solar panels.

Aldo di Carlo, lead author and researcher in Graphene Flagship partner University of Rome Tor Vergata, explains: "Our new approach to manufacture graphene-enabled tandem solar cells provides a double advantage. First, it can be applied to enhance all the different types of perovskite solar cells currently available, including those processed at high temperatures. But more importantly, we can incorporate our graphene using the widespread 'solution manufacturing methods', key to further deploy our technologies industrially and deliver large-surface, graphene-enabled solar panels."

Francesco Bonaccorso, co-author, co-founder of Graphene Flagship spin-off BeDimensional, says: "This innovative approach proposed in the context of the Graphene Flagship is the first step toward the development of tandem solar cells delivering an efficiency higher than the limit of single junction silicon devices. Layered materials will be pivotal in reaching this target.".

Emmanuel Kymakis, Graphene Flagship Energy Generation Work Package Leader, says: "There are some compatibility issues that have to be tackled before the full exploitation of the perovskite-Si tandem PVs concept. This pioneering work demonstrates that the integration of GRMs inks with on-demand morphology and tuneable optoelectronic properties in a tandem structure, can lead to high-throughput industrial manufacturing. Graphene and related materials improve the performance, stability and scalability of these devices. The stacked silicon-perovskite configuration will act as the foundation of the new Graphene Flagship Spearhead Project GRAPES, in which a pilot line fabrication of graphene-based perovskite-silicon tandem solar cells will take place, paving the way towards breaking the 30% efficiency barrier and a significant decrease on the Levelized Cost of Energy."

Andrea C. Ferrari, Science and Technology Officer of the Graphene Flagship and Chair of its Management Panel, adds: "The application of graphene and related materials to solar energy generation was recognized as a strategic priority since the start of the Graphene Flagship. The first graphene-based solar farm is being set up this year. These new results underpin our effort for the following 3 years to produce panels defining the state of the art. This also shows how the work of the Graphene Flagship strongly aligns with the UN's Sustainable Development Goals."

An insect's compound eye has superior visual characteristics such as wide viewing angle, high motion sensitivity, and large depth of field while maintaining a small volume of visual structure with a small focal length. Among them, Xenos peckii, an endoparasite of paper wasps, eyes have hundreds of photoreceptors in a single lens unlike conventional compound eyes with a few light-sensing cells in an individual eyelet. This unique structure offers higher visual resolution than other insect eyes. The Xenos peckii eye also perceives partial images through pigmented cups that block incoming light between eyelets.

Inspired from Xenos peckii eye structure, a KAIST research team led by Professor Jeong Ki-Hun demonstrated a fully packaged ultrathin insect eye camera. They developed a unique and new configuration of micro-optical element to completely suppress the optical noise between microlenses while reducing camera thickness. This optical component was integrated with a complementary metal oxide semiconductor (CMOS) image sensor and the final thickness of fully packaged camera lens is only 740 μm.

The fully packaged ultrathin arrayed camera has successfully demonstrated high contrast clear array images acquired from tiny microlenses. To further enhance image quality of the captured image, they have discussed the vision principle of insect eye and combined the array images into one image through super-resolution imaging. This work also shows the first demonstration of super-resolution imaging, which acquires a single integrated image with high contrast and high resolving power reconstructed from high contrast array images.

"This work reports the first demonstration of ultrathin arrayed camera for high contrast and super resolution imaging. We strongly believe our study will make solely technical advances and also have significant impacts on multidisciplinary communities of micro and nanotechnology mining the smartness from natural photonic structures," said Jeong.

Tokyo, Japan - The importance of the microorganisms that live on and in our bodies has long been recognized, and their complex synergistic impact on our systemic health is elucidated. Now, researchers from Japan have shown the importance of normal eating for the composition and balance of our individual oral and gut microbiota.

In a study published in Frontiers in Cellular and Infection Microbiology in December 2019, researchers from Tokyo Medical and Dental University (TMDU) have shown the importance of normal feeding for establishing and maintaining appropriate bacteria in the mouth and the gut.

Our bodies are symbiotic units of human cells and microorganisms. Far from being deleterious, this microbiota is now recognized as a vital modulator of functions such as digestion, mood, sleep and response to drugs, as well as susceptibility to diabetes, autism, obesity and cancer.

Patients convalescing from stroke often have dysphagia, and need to be fed via a tube to bypass the mouth. "We hypothesized that resuming oral food intake could modify the composition of oral and gut microbial communities in tube-fed patients," explains senior author Haruka Tohara, Associate Professor of Gerodontology and Oral Rehabilitation at TMDU. "To test this, we compared oral and gut microbiome profiles before and after the resumption of oral food intake in eight post-stroke patients recovering from enteral nutrition."

Senior author, Takahiko Shiba, elaborates further: "We evaluated oral and gut microbiota community profiles by sequencing 16s rRNA in saliva and feces samples collected when the patients were being fed via tube and after they switched back to eating normally. We then examined the co-occurrence and interaction patterns of the microbial communities and conducted computational prediction of their function."

The researchers were surprised to find that re-initiation of oral food intake dramatically altered and diversified both oral and gut microbiomes. Though very different in composition, both showed an increase of the family Carnobacteriaceae and genus Granulicatella suggesting that orally ingested bacteria may directly modulate the gut community thus affecting systemic health. Although oral microbiota alteration was more significant than that in the gut, metagenome prediction showed more differentially enriched pathways in the gut, especially those related to fatty acid metabolism.

"Networks in both microbiomes were simpler and fewer, which may indicate healthier restructuring," observes lead author Sayaka Katagiri, Assistant Professor of Periodontology at TMDU. "Additionally, altered interaction between core species suggests improved microbiome balance."

Given the problems associated with tube feeding, this study provides another overwhelming motive for early reversion to normal feeding: that of restoring a beneficial oral and gut microbiome.

Playing back recorded audio from a digital storage allows us to enjoy music without the physical presence of a musical instrument to generate resonating sound. In a seemingly unrelated area called metamaterials, scientists design different physical structures also resonating with sound or light, to achieve many intriguing phenomena such as negative refraction and invisibility.

Recently, scientists from the Hong Kong University of Science and Technology (HKUST), in collaboration with Seoul National University in Korea, have realized what they called a virtualized acoustic metamaterial, in digitizing material response to an impulse response stored in a software program. Such a digital representation is common in signal processing to construct filters but now as a new application to material science. The digital representation replaces the previous physical structures, leaving only a collection of microphones and speakers inter-connected with a backend microprocessor. The impulse response of the metamaterial is now simply a software program in generating any scattered wave with a tailor-made frequency dispersion. As such, the response of metamaterials can be made arbitrary and flexibly tuned by simply a click of button.

Their findings were published in the journal Nature Communications on January 14, 2020.

"Current approach in metamaterial research mimics the response of natural atoms by artificially constructed ones using resonating physical structures. But that suffers for a long time a limitation that the property cannot be tuned easily in a large range and in a dynamical fashion," said Prof. Jensen LI Tsan-Hang of the Department of Physics, HKUST, who led the research. "This is particularly important for many realistic applications, such as a broadband stealth, that has to work in a dynamic and in a stringent environment."

"Our work tackles this problem and provides a feasible approach to digitize the response into a software program. A digital representation of a metamaterial, by borrowing a popular concept of impulse response in signal processing, the response of metamaterial can be tuned and changed by simply a click of button to change the software program," Prof. Li said.

While metamaterials have been showing high commercial values in terms of their superior performance in soundproofing, making compact meta-lens, etc., such a virtualization technology will further add huge tunability in terms of functions, assigning another level of meaning to "meta", and allowing metamaterials to do broadband stealth, active sound absorption, super-resolution imaging, and beyond.

"With our approach, we can easily go into the active regime of metamaterials, in addition to the tunability we have mentioned. External electronics, in comparing to conventional metamaterials that consist of passive physical structures, can always provide power to the metamaterials," said Prof. Namkyoo PARK, of the Department of Electrical and Computer Engineering, Seoul National University. "We are not restricted to metamaterials that can only be passive or dissipating power; any active response can be specified easily. We prove this in our work by realizing a metamaterial with amplified transmission much larger than value one."

"By replacing the resonating physical structure with a designer mathematical convolution kernel with a fast digital signal processing circuit, we demonstrate a decoupled control of the effective bulk modulus and mass density of acoustic metamaterials on-demand through a software-defined frequency dispersion," said Prof. Li. "Providing freely software-reconfigurable amplitude, center frequency, bandwidth of frequency dispersion, our approach adds an additional dimension to constructing non-reciprocal, non-Hermitian, and topological systems with time-varying capability as potential applications."

The next step of the research group will involve building up a much larger version of meta-atoms of a metamaterial, which will allow researchers to further manipulate sound waves with properties that go beyond the current generation of metamaterials, such as broadband invisibility, extreme non-reciprocal transmission or sound proofing.

It has probably never been easier to find a partner who is compatible with you - at least in theory. Internet dating platforms feed algorithms with information about those seeking a relationship in order to find the best match for them. But can this predictability be applied to a relationship? Is it possible to foresee from the start whether it will last?

Psychologists of Friedrich Schiller University Jena, Germany, and the University of Alberta, Canada, have looked into this question and have come to a clear conclusion: "Predictions as to the longevity of a relationship are definitely possible," says Dr Christine Finn from the University of Jena. In the long-term study 'pairfam', she held regular interviews over seven years with nearly 2,000 couples, 16 per cent of which broke up during this period. "Right at the outset of a relationship, one can find typical features - that is to say certain prediction variables - that provide information on whether or not the relationship will be long-lasting."

Those who start off unhappy will become even more unhappy

In psychology, there are currently two scientific models, which describe the course of a relationship in different ways, explains Finn. One posits that all couples are initially more or less equally happy. If the relationship ends in separation, this can be traced back to problems that only developed over the course of the couple's time together. The second model assumes that the two individuals in a couple start at different levels of happiness. They generally maintain these levels, but a more negative initial situation increases the likelihood of failure. "We have now discovered that there is actually a combination of the two models," says Finn. "We too can confirm that there are differing levels to begin with. In addition, happiness declines in both groups. However, in those who later separate, this happens significantly faster, meaning that a person who starts off unhappy becomes increasingly unhappy."

Therefore, the beginning of a relationship can reveal something about how it will progress. The researchers in Jena determined satisfaction by, for example, asking couples to what extent they considered that their needs were being met. In general, people who have similar needs, for example a need for closeness, but who also want to be able to continue pursuing their own interests, usually stay together longest.

No demand for optimisation

With the help of this new scientific information, couples could therefore have advance information on the probability of their staying together. But is such information useful? Christine Finn is sceptical: "It is not our intention to further reinforce the general trend for optimisation and only to have a relationship that is result-oriented, with the prospect of it being long-lasting. Even if couples split up after a time, it can still be a valuable and important phase in their lives, which might have a positive influence on the next relationship. Furthermore, couples can also consciously influence and work on their mutual interests and on cultivating closeness as well as independence. No relationship is doomed to fail from the outset." In this sense, the results of the study could be of value to counselling centres and therapists.

The scientific observation of such relationships is only possible thanks to the long-term study 'pairfam' (Panel Analysis of Intimate Relationships and Family Dynamics). In this project, researchers at four German universities have been studying the development of 12,000 individuals of various ages since 2008. The study, which is funded by the German Research Foundation, will run until part-way through 2022.

A study led by the University of Turku, Finland, has found that small, fiercely predatory damselflies catch and eat hundreds of thousands of insects during a single summer - in an area surrounding just a single pond. In terms of weight, this equates to a total prey mass of just under a kilo. Dragonflies mostly catch different kinds of midges, but also large numbers of other insects.

Who keeps numbers of insect in check during the summer? This has been debated for some time, but a clear answer has remained elusive, as it has been difficult to monitor the numbers consumed by different insect predators. A new study now sheds light on the role of dragonflies that occur in large numbers.

Even in just a small area, populations of matchstick-sized damselflies that whiz around, consume hundreds and thousands of insects. Although the numbers of prey species individuals hatching in the area is as much as one hundred times the quantities being consumed by the damselflies, the quantity consumed is nevertheless significant because there are many other predators also preying on the same prey species.

The results of the novel study were obtained by combining multiple scientific methods. The prey species of the dragonflies and their relative quantities were assessed by examining prey DNA extracted from the faeces of damselflies, using a method known as metabarcoding. Population estimates of dragonflies were also obtained.

- We investigated the numbers of dragonflies by marking them with a series of numbers on their wings, releasing them and then catching them again. By comparing the numbers of marked and unmarked dragonflies caught, we were able to estimate the total number of individuals in the area. The numbers of insects consumed, meanwhile, were estimated by covering certain areas with tent-like hatching traps and counting how many insects accumulated in them over a particular surface area, explains Senior Researcher Kari Kaunisto from the Biodiversity Unit of the University of Turku, who led the study.

Chironomids are damselflies' favourite food

Dragonflies are among the apex predators of the insect world and are considered to be responsible for regulating the numbers of many other insect species. During the period studied, the insect species consumed the most by the damselflies were different chironomids.

- In the 12-hectare area we studied, the catch mass for the four species of dragonflies was about 900 grams, equivalent to about 700,000 medium-sized midges. This equated to around 1% of the total mass of the midge populations in the area. This amount should not, however, be disregarded, as damselflies are by no means the only predators of midges and other insects. The area we are studying has an enormous number of other predators, including twenty other species of dragonfly, as well as birds and bats, explains Docent of Molecular Ecology Eero Vesterinen from the Biodiversity Unit of the University of Turku, who was responsible for the project's DNA analyses.

Dragonflies have always fascinated people, as they are impressive insects and effective predators. Dragonflies are also particularly at risk because they are apex predators in natural ecosystems.

- In this study, we focused on four small but locally abundant damselfly species from among the 62 dragonfly species found in Finland, Vesterinen adds.

The species studied were the common blue damselfly (Enallagma cyathigerum), the northern damselfly (Coenagrion hastulatum), the Irish damselfly (Coenagrion lunulatum), and the variable damselfly (Coenagrion pulchellum).

New information on natural food web functions

Understanding the functioning of the food webs is particularly important now, when natural diversity is diminishing at an accelerating rate.

- For the first time, our study examined the intensity of insect hunting in relation to the total number of insects being preyed on. The collapse of insect populations reduces the amount of food available to dragonflies, but it has not been possible to assess the impacts of predation by dragonflies without this accurate information on food chains, says Kaunisto.

Professor Tomas Roslin from the Swedish University of Agricultural Sciences, who participated in the study, is really excited about the new approach and the interesting results of the study.

- By combining several methods, the research reveals the overall impact of predation in nature. We succeeded in revealing both the wide range of insects preyed on by dragonflies and the significance of predation in relation to both individual prey species as well as the community as a whole, Roslin exclaims.

Our world has no dearth of complex networks--from cellular networks in biology to intricate web networks in technology. These networks also form the basis of various applications in virtually all fields of science, and to analyze and manipulate these networks, specific "search" algorithms are required. But, conventional search algorithms are slow and, when dealing with large networks, require a long computational time. Recently, search algorithms based on the principles of quantum mechanics have been found to vastly outperform classical approaches. One such example is the "quantum walk" algorithm, which can be used to find a specific point or a "vertex" on a given N-site graph. Instead of simply going through neighboring vertices, the quantum walk approach employs probabilistic estimations based on the quantum mechanical theory, which drastically reduces the number of steps required to find the objective. To achieve this, before moving from one point to another, an operation called "oracle call" needs to be performed repeatedly to adjust the probability values in the quantum system representation. One main issue is to understand the relationship between the optimal computational time of the oracle call and the structure of the network, as this relationship is well understood for standard shapes and bodies, but it remains unclear for complex networks.

In a new study published in Physical Review A, a team of scientists at Tokyo University of Science, led by Prof Tetsuro Nikuni, dug deeper into the intricacies of these networks in an effort to develop more efficient quantum algorithms. Prof Nikuni explains, "Many real-world systems, such as the World Wide Web and social/biological networks, exhibit complex structures. To fully explore the potential of these network systems, developing an efficient search algorithm is crucial."

To begin with, the scientists looked into the "fractal properties" (geometrical properties of figures that seem to infinitely replicate their overall shape) of networks. The researchers focused on some basic fractal lattices (structures with a fractal network), such as "Sierpinski gasket," "Sierpinski tetrahedron," and "Sierpinski carpet," to try to find out the relationship between the number of vertices (nodes of the network) and the optimal computational time in a quantum walk search. To this end, they performed numerical simulations with over a million vertices and checked whether the results were in line with previous studies, which proposed a mathematical law or a "scaling law" to explain this relationship.

The researchers found that the scaling law for some fractal lattices varied according to their spectral dimension, confirming the previous conjecture for other lattices. Surprisingly, they even found that the scaling law for another type of fractal lattice depends on a combination of its intrinsic characteristics, again showing that the previous conjecture on the optimal number of oracle calls might be accurate. Prof Nikuni says, "It may indeed be a fact that the quantum spatial search on fractal lattices is surprisingly subject to combinations of the characteristic quantities of the fractal geometry. It remains an open question as to why the scaling law for the number of oracle calls is given by such combinations." With this understanding, the team even proposed a new scaling hypothesis, which slightly differs from the ones proposed earlier, so as to gain more insight into different fractal geometries of networks.

The research team hopes that, with their findings, quantum searches will become easier to analyze experimentally--especially with recent experiments performing quantum walks on physical systems like optical lattices. The wide applicability of quantum algorithms on fractal lattices highlights the importance of this study. Owing to its exciting findings, this study was even selected as "Editor's suggestion" in the February 2020 issue of Physical Review A. Optimistic about the results and with future research directions laid out, Prof Nikuni concludes, "We hope that our study further promotes the interdisciplinary study of complex networks, mathematics, and quantum mechanics on fractal geometries."

Immune system T-cells are more able to destroy skin cancer cells when a T-cell regulator called SLAMF6 is missing, a new study in eLife shows.

Immunotherapies, which boost the immune system's ability to destroy cancer cells, have become an important type of cancer treatment, but they are only successful for about half of patients treated with them. The new study in mice suggests that immunotherapies that turn off SLAMF6 might add an option that could be used alone or in combination with other immunotherapies to treat cancer more effectively.

"There is a real need to find new targets for immunotherapies," says lead author Emma Hajaj, an MD-PhD candidate at the Sharett Institute of Oncology at Hadassah Hebrew University Hospital, Jerusalem, Israel. "We thought that SLAMF6, which is a receptor found on all T-cells, was a good candidate for immunotherapy, but more thorough research was needed to confirm this."

To investigate this further, Hajaj and her colleagues created a mouse model that enabled the team to understand the role of SLAMF6 in melanoma treatment. They found that tumours in mice treated with SLAMF6-lacking T-cells shrunk faster and stayed smaller than tumours in mice treated with typical T-cells.

Additionally, they saw that the expression of a gene called LAG-3 increased in the SLAMF6-lacking cells, possibly to make up for the loss of the regulator. Combining SLAMF6-lacking T-cells with an antibody that blocks LAG-3 also increased their tumour-shrinking effect.

"The results from our study show that the absence of SLAMF6 unleashes powerful anti-tumour T-cells, which extended survival in our mouse model," explains senior author Michal Lotem, Head of the Center for Melanoma and Cancer Immunotherapy at Hadassah Hebrew University Hospital. "These findings may have important implications for cancer immunotherapy and could lead to the development of new melanoma treatments that turn off SLAMF6."

Following the latest research in the field of obtaining single-molecule magnets (SMMs), scientists have taken another step on the way toward obtaining super-dense magnetic memories and molecular neural networks, in particular the construction of auto-associative memories and multi-criterion optimization systems operating as the model of the human brain. Interestingly, this was achieved by using methods available in an average chemical laboratory.

Up to 100 million bits in one square millimetre of magnetic storage devices? Neural networks made out of single molecules? The work carried out by a team led by Lukasz Laskowski from the Department of Molecular Engineering and Nanoelectronics of the Institute of Nuclear Physics of the Polish Academy of Sciences which focuses on the separation of individual particles of molecular magnets brings us closer to achieving these goals.

Until the end of the 1980s, a widely accepted opinion prevailed that ferromagnetic properties are associated with the crystal structure and can only be related to appropriately bulky crystalline matter. However, in 1991, a material made of Mn12O12(OAc)16(H2O)4 molecules, also known as Mn12-stearate, appeared, which contradicted this common belief. It turned out that below a certain temperature this material exhibits ferromagnetic properties. It is worth emphasizing that these magnetic properties did not result from the properties of the crystal structure, as in the case of ferromagnetics, but from the characteristics of a single molecule. That is why materials of this type were called single-molecule magnets (SMMs).

It is not difficult to imagine the application of such compounds, for example in super-dense memory units or elements of neural networks. Therefore, it would seem that single-molecule magnets will quickly become widely used. However, this did not happen. This was probably caused by problems with their separation and obtaining a proper system of individual molecules spaced far enough away from each other that prevented them from affecting each other. Moreover, after obtaining such a system, it was necessary to develop a method for observing molecules as small as 2 nm.

So how can one make the most of the properties of single-molecule magnets? How to arrange individual particles of such material on the substrate so that they do not lose their properties? How to verify the emergence of such a system? Is it necessary to use sophisticated technologies for this purpose?

The basic assumption of the project was to obtain separated single-molecule magnets on a magnetically neutral substrate and to directly observe such molecules without the use of advanced laboratory techniques. The priority was the subsequent use of the developed procedures for commercial applications. After choosing the characteristics of the material in terms of physicochemical and mechanical characteristics, and molecular structure, it was necessary to develop a synthesis procedure in such a way that the atoms would expectedly arrange themselves, creating the desired nanomaterial. Then, the researchers had to choose a single-molecule magnet, a substrate (matrix), the type of anchoring molecules on the surface of the substrate, the way to control their distribution and the distance between them, and methods for direct observation of such molecules.

At the stage of selecting possible types of single-molecule magnets, the Mn12-stearate compound was recognized as the most promising. This particle has a high ground-state spin S = 10 and, therefore, a strong magnetic moment. Due to some modifications, the soluble form of Mn12-stearate was obtained, which additionally proved to be more resistant to atmospheric impact.

When considering the type and form of the medium used, the scientists took into account the aspect of observation of the obtained material. Explicit confirmation of the success would be the direct observation of Mn12-stearate molecules on the surface of the matrix. However, this was difficult due to their small size of only about 2 nm. The solution turned out to be the application of spherical silica. Single-molecule magnets were deposited on spherical silica particles with a diameter of approximately 300 nm. With the spherical shape and relatively small size of such a substrate, they could be clearly observed using transmission electron microscopy (TEM). In particular, the team focused on observing the very horizon (periphery) of such a sphere and detecting the single-molecule magnets anchored to it (Figs 1 and 2).

The surface of the silica chosen as the substrate for the deposition of magnetic molecules has numerous hydroxyl groups, which can then be altered into anchoring units. The method of anchoring the molecules depends on attaching butyl-nitrile groups to the surface hydroxyl units and then transformed into propyl carboxyl groups by hydrolysis. These, in turn, easily capture and immobilize individual Mn12-stearate molecules. The problem of controlling anchor distribution was overcome, however, with the help of spacer units, which allows for monitoring of the distribution of anchoring units during synthesis.

The materials were synthesized in the laboratory of the Department of Molecular Engineering and Nanoelectronics of the Institute of Nuclear Physics of the Polish Academy of Sciences. The work involving the materials has been carried out since 2018. The substances obtained were tested with regards to structural properties using TEM microscopy and vibrational spectroscopy. Magnetic properties were determined using SQUID magnetometry.

The obtained results directly prove that the research group managed to place individual magnetic particles on the silica surface. The procedure is robust, repeatable, and uncomplicated, therefore it can be used by scientific and industrial units fitted out with average equipped laboratories. Besides, a very simple method of direct observation of tiny molecules deposited on a silica substrate was implemented--Mn12-stearate molecules were clearly visible, especially near the horizon of spherical silica using TEM microscopy. No one has ever applied this procedure before. An equally important research achievement proved to be the observation that single-molecule magnets retain their properties, even when separated from each other and embedded on the substrate. In addition, it was possible to determine the way of anchoring magnetic molecules depending on the concentration of anchoring units.

The results obtained are very important and encourage further work on this type of material. Currently, the team is working on analyzing the detailed results of magnetic measurements for the substances described here as a function of the concentration of Mn12-stearate molecules. The scientists are also investigating the durability of the nanocomposites fabricated. The next step will be the regularization of the obtained systems. Currently, the distance between magnetic molecules is regulated statistically, but ultimately, Mn12-stearate single-molecule magnets are to be arranged on the substrate in a regular hexagonal configuration. This will be possible with the use of mesoporous silica with an ordered structure of channels in the form of a thin film and precise multi-stage functionalization of the substrate.

A small molecule that inhibits energy production in immune T-cells allows some tumours to escape treatment with an immunotherapy called PD-1 blockade therapy, says a study in mice published today in eLife.

Cancer therapies that help boost the immune system's defences to tumour cells are a promising new approach to treatment. One such therapy blocks PD-1, a receptor on the surface of T-cells. Cancer cells express a protein that binds to this receptor and interferes with the T-cell's ability to kill tumour cells. But while drugs that block this receptor can reactivate the T-cells, they are not always effective and the results of the new study help explain why.

"Despite the great success of PD-1 blockade therapy, we need to improve its efficacy because more than half of patients' tumours don't respond to it," says lead author Alok Kumar, a PhD student in the Department of Immunology and Genomic Medicine at Kyoto University, Japan.

To learn why so many tumours fail to respond to PD-1 blockade therapy, Kumar and his colleagues studied mice with two types of tumour cells: some that were sensitive to PD-1 blockade therapy and others that were not. This allowed the team to identify two different types of tumours that do not respond to PD-1. One type suppressed the immune system and caused even the PD-1-sensitive tumour cells to grow, while the other had no effect on PD-1-sensitive tumour cells.

"We found that some human cancer cells release immunosuppressive molecules that inhibit the activity of energy-producing mitochondria in T-cells," Kumar explains. Treating the mice with a mitochondria-boosting compound reversed this effect in the immune-suppressing tumour.

However, the treatment had no effect on the other type of tumour. Instead of impairing energy production in T-cells, the other tumour made itself invisible to the immune system by failing to produce a protein that helps immune cells recognise tumour cells.

The identity of the molecule that helped the first type of tumour suppress mitochondria is currently unknown. The researchers hope that if they can find it, they can create drugs that hinder its activity. "If we could identify these unknown factors and develop drugs that block them, we could save patients' lives by using the drugs alongside PD-1 blockade therapy to prevent tumours from defending themselves," says senior author Tasuku Honjo, Professor of Immunology and Genomic Medicine at Kyoto University.

Most people know that good oral hygiene - brushing, flossing, and regular dental visits - is linked to good health. Colorado State University microbiome researchers offer fresh evidence to support that conventional wisdom, by taking a close look at invisible communities of microbes that live in every mouth.

The oral microbiome ­- the sum total of microorganisms, including bacteria and fungi, that occupy the human mouth - was the subject of a crowd-sourced, citizen science-driven study by Jessica Metcalf's research lab at CSU and Nicole Garneau's research team at the Denver Museum of Nature & Science. Published in Scientific Reports, the study found, among other things, a correlation between people who did not visit the dentist regularly and increased presence of a pathogen that causes periodontal disease.

For the experiments, carried out by Garneau's community science team in the Genetics of Taste Lab at the museum, a wide cross-section of museum visitors submitted to a cheek swab and answered simple questions about their demographics, lifestyles and health habits. Microbial DNA sequencing data analyzed by Metcalf's group revealed, broadly, that oral health habits affect the communities of bacteria in the mouth. The study underscored the need to think about oral health as strongly linked to the health of the entire body.

"Our study also showed that crowdsourcing and using community scientists can be a really good way to get this type of data, without having to use large, case-controlled studies," said Zach Burcham, a postdoctoral researcher and the paper's lead author. Senior author Metcalf is an associate professor in the Department of Animal Sciences and a member of CSU's Microbiome Network.

Cheek swabs

Back in 2015, paper-co-author Garneau and her team trained volunteer citizen scientists to use large swabs to collect cheek cells from museum visitors ­­- a naturally diverse population - who consented to the study. These trained citizen scientists helped collect swabs from 366 individuals - 181 adults and 185 youth aged 8 to 17.

The original impetus for the study was to determine whether and to what extent the oral microbiome contributes to how people taste sweet things. In collecting this data, which was also reported in the paper, the researchers noted more significant data points around oral health habits.

To help translate the data, Garneau turned to Metcalf's team of experts at CSU. Burcham and the microbiome scientists employed sophisticated sequencing and analysis tools to determine which microbes were present in which mouths. Sequencing for the data was performed in collaboration with scientists in Rob Knight's group at University of California San Diego. A nutrition team from Michigan State University also brought in expertise on the importance of child and maternal relationships to the data analysis.

"Together, we had a dream team for using community science to answer complicated questions about human health and nutrition, using state-of-the-art microbial sequencing and analysis," Garneau said.

Flossing and regular dental care

The study grouped people who flossed or didn't floss (almost everyone said they brushed, so that wasn't a useful data point). Participants who flossed were found to have lower microbial diversity in their mouths than non-flossers. This is most likely due to the physical removal of bacteria that could be causing inflammation or disease.

Adults who had gone to a dentist in the last three months had lower overall microbial diversity in their mouths than those who hadn't gone in 12 months or longer, and had less of the periodontal disease-causing oral pathogen, Treponema. This, again, was probably due to dental cleaning removing rarer bacterial taxa in the mouth. Youth tended to have had a dental visit more recently than adults.

Youth microbiomes differed among males and females, and by weight. Children considered obese according to their body mass indices had distinct microbiomes as compared to non-obese children. The obese children also tended to have higher levels of Treponema, the same pathogen found in adults who hadn't been to the dentist in more than a year. In other words, the researchers saw a possible link between childhood obesity and periodontal disease. "This was very interesting to me, that we were able to detect these data in such a general population, with such a variable group of people," Burcham said.

Other data uncovered: The microbiomes of younger participants, mostly in the 8- to 9-year-old range, had more diversity than those of adults. However, adult microbiomes varied more widely from person to person. The researchers think this is due to the environments and diets of adults being more wide-ranging than children.

They also saw that people who lived in the same household shared similar oral microbiomes.

"When you look at families who live together, you find they share more of those rare taxa, the bacteria that aren't found as often in higher abundances," Burcham explained. It was a data point that underscored the relevance of one's built environment in relationship to the microbial communities in our bodies.

Working on the mouth study was fascinating, albeit outside Burcham's normal scope; he is usually focused on studying microbial ecology of decomposition.

"I think how our lives are essentially driven by our microbiomes, and affected by our microbiomes, is interesting, no matter what system we're looking at," Burcham said.

With a small zap of electricity, biomedical engineers at Michigan Technological University take an underwater smart glue prototype from sticky to not in seven seconds.

Turning adhesion on and off is what makes a glue smart. It's one thing to do this in the open air and quite another under water. Inspired by nature, catechols are synthetic compounds that mimic the wet-but-still-sticky proteins secreted by mussels and offer promise for smart adhesives that work in water. The technology could help with underwater glue, wound dressings, prosthetic attachments or even making car parts and in other manufacturing.

Bruce Lee, associate professor of biomedical engineering at Michigan Tech, is a part of the Office of Naval Research's (ONR) Young Investigator Program (YIP) and showed how to use pH to make smart underwater adhesives. Along with doctoral researcher Saleh Akram Bhuiyan, Lee developed a new method using an electrical current to turn off the adhesion of a catechol-containing material.

The team's findings came out in the Journal of the American Chemical Society and detailed the stickiest part of the process -- creating a repeatable contact mechanics test that can measure adhesion before and after a jolt of electricity.

"A lot of people have been using catechol to mimic mussels and their adhesive proteins, but applying electricity to deactivate it is new," Lee said. "It's more convenient than using pH like what we were using before and it should be easier to integrate with electronic devices, which means detaching could be automated and could be as simple as pushing a button."

One day catechol adhesives may help attach equipment to the hulls of submarines but testing prototypes in scuba gear isn't how new tech gets created. Instead, Lee and Bhuiyan need to control a suite of variables in a small lab space. Simple as it sounds, running a current through a material and checking its stickiness is actually quite difficult to do over and over again.

Bhuiyan developed a setup that uses a titanium sphere and a platinum wire electrode to apply electrical stimulation to the adhesive that is in contact with the sphere in the presence of salty water. This method makes it easy to control the voltage applied through the wire, glue and sphere as well as how salty the water is around them. The amount of time the current runs is also important. With more time, voltage and salt, the more the catechol adhesives gets oxidized and the less adhesive it becomes. With strong enough voltage, the glue detaches in only seven seconds.

"The novelty is application of the electricity and the short amount of time it takes to detach," Bhuiyan said. "What I find most unusual about the experiment is the color change. It starts white and when I apply the electricity and the material is deactivated, it oxidizes and turns a red color -- and we really like to see that red color."

The next step in the research will be taking that red and trying to turn it back into white. The hallmark of a smart glue is not only deactivating adhesion, but turning it back on. Lee and doctoral graduate Ameya Narkar were able to accomplish this feat by playing with pH, which earned them the Bhakta Rath Research Award, and Bhuiyan hopes to apply the lessons from that research to using electrical current.

From painless bandages to underwater glue, from automotive gear to prosthetic limbs, catechol-containing adhesives are versatile and promising materials.

A smartphone app that allows users to check for jaundice in newborn babies simply by taking a picture of the eye may be an effective, low-cost way to screen for the condition, according to a pilot study led by UCL and UCLH.

Jaundice, where the skin and whites of the eyes turn yellow, causes 114,000 newborn deaths and 178,000 cases of disability a year worldwide, despite being a treatable condition. Three quarters of deaths are in south Asia and sub-Saharan Africa.

The study, published in PLOS ONE, found that a new screening method quantifying the yellowness of the eye - which used images captured on a smartphone camera - can be as effective at detecting more severe jaundice as costly screening devices recommended for use in the UK.

Dr Terence Leung (UCL Medical Physics & Biomedical Engineering), senior author of the paper, said: "In many parts of the world, midwives and nurses rely on sight alone to assess jaundice. However, this is unreliable, especially for newborns with darker skin.

"Our smartphone-based method provides a more robust assessment, ensuring serious cases do not go unnoticed. While we await the evidence of a larger trial, we believe that this method, used as an app, could help to prevent the deaths of newborn babies due to severe jaundice worldwide."

Jaundice is caused by a yellow substance called bilirubin accumulating in the body. While most cases in newborns are harmless, in severe cases a neurotoxic form of bilirubin can enter the brain, leading to death or disabilities such as hearing loss, neurological conditions such as athetoid cerebral palsy, and developmental delays.

In hospitals, newborns suspected of being at risk can be given a blood test to determine the concentration of bilirubin in the blood. However, jaundice may only become problematic several days after birth, when mother and newborn are at home.

In the study, smartphone pictures were taken of the eyes of 37 newborn babies at UCLH who had been referred for blood tests. These images were processed to remove the distorting effects of background light and the yellowness of the eye quantified to predict the level of bilirubin in the blood.

These predictions were then compared to the results of the blood tests. The method successfully identified all cases where treatment would normally be required, while identifying cases that would not require treatment 60% of the time. This is a success rate comparable to transcutaneous bilirubinometers - expensive hand-held devices recommended for use by midwives in the UK.

First author, Felix Outlaw (UCL Medical Physics & Biomedical Engineering), said: "Our screening method would require no special equipment apart from a smartphone and is a tenth of the cost of commercial devices used in the UK.

"Given that smartphones are common even in poor and remote parts of the world, being able to use them to screen for jaundice would have a significant impact."

A larger trial of the screening method involving more than 500 babies is now underway in Ghana. The trial, a collaboration between UCL and the University of Ghana as well as Greater Accra Regional Hospital, is funded by the "Saving Lives at Birth" award, with funders including the United States Agency for International Development (USAID), the government of Norway, the Bill & Melinda Gates Foundation, Grand Challenges Canada, the UK government, and the Korea International Cooperation Agency (KOICA).

TROY, N.Y. -- From cell phones, to solar power, to electric cars, humanity is increasingly dependent on batteries. As demand for safe, efficient, and powerful energy storage continues to rise, so too does the call for promising alternatives to rechargeable lithium-ion batteries, which have been the dominant technology in this space.

In research published in Proceedings of the National Academy of Sciences, researchers from Rensselaer Polytechnic Institute demonstrate how they can overcome a persistent challenge known as dendrites to create a metal battery that performs nearly as well as a lithium-ion battery, but relies on potassium -- a much more abundant and less expensive element.

Batteries contain two electrodes -- a cathode on one end and an anode on the other. If you were to look inside a lithium-ion battery you'd typically find a cathode made of lithium cobalt oxide and an anode made of graphite. During charging and discharging, lithium ions flow back and forth between these two electrodes.

In this setup, if researchers were to simply replace lithium cobalt oxide with potassium cobalt oxide, performance would drop. Potassium is a larger and heavier element and, therefore, less energy dense. Instead, the Rensselaer team looked to boost potassium's performance by also replacing the graphite anode with potassium metal.

"In terms of performance, this could rival a traditional lithium-ion battery," said Nikhil Koratkar, an endowed professor of mechanical, aerospace, and nuclear engineering at Rensselaer and the lead author on this paper.

While metal batteries have shown great promise, they have also traditionally been plagued by accumulation of metal deposits, called dendrites, on the anode. Dendrites are formed because of non-uniform deposition of potassium metal as the battery undergoes repeated cycles of charging and discharging. Over time, Koratkar explained, the conglomerates of potassium metal become long and almost branch-like.

If they grow too long, they will eventually pierce the insulating membrane separator meant to keep the electrodes from touching each other and shorting out the battery. Heat is created when a battery shorts and has the potential to set the organic electrolyte within the device on fire.

In this paper, Koratkar and his team — which included Prateek Hundekar, a doctoral student at Rensselaer, and researchers from the University of Maryland, including Chunsheng Wang, a professor of chemical and biomolecular engineering — explain how their solution to that problem paves the way for practical consumer use. By operating the battery at a relatively high charge and discharge rate, they can raise the temperature inside the battery in a well-controlled manner and encourage the dendrites to self-heal off the anode.

Koratkar compares the self-healing process to what happens to a pile of snow after a storm has ended. The wind and the sun help move the flakes off the mound of snow, shrinking its size and eventually flattening it out.

In a similar way, while the temperature increase within the battery won’t melt the potassium metal, it does help to activate surface diffusion so the potassium atoms move laterally off the “pile” they’ve created, effectively smoothing the dendrite out.

"With this approach, the idea is that at night or whenever you're not using the battery, you would have a battery management system that would apply this local heat that would cause the dendrites to self-heal," Koratkar said.

Koratkar and his team previously demonstrated a similar method of self-healing with lithium metal batteries, but they found the potassium metal battery required much less heat to complete the self-healing process. That promising finding, Koratkar said, means a potassium metal battery could be more efficient, safe, and practical.

"I want to see a paradigm shift to metal batteries," Koratkar said. "Metal batteries are the most efficient way to construct a battery; however, because of this dendrite problem they have not been feasible. With potassium, I'm more hopeful."