Tech

Certain perovskite compounds are seen as a great hope for better and, above all, even cheaper solar cells. Their crystal lattice is formed by organic methylammonium cations (MA+) surrounded by heavy metal atoms (lead or tin) and atoms like iodine. The best perovskite solar cells today are realized with lead. In just ten years of research, the efficiency of these solar cells in the laboratory has been increased from 4 percent (2009) to over 25 percent (2019). However, lead is toxic and must not enter the food chain. On the other hand, very little lead is needed for a solar module: a square metre perovskite solar module contains only 0.8 grams of lead, which is very little compared to other technical sources of lead (e.g. in batteries).

Now a team led by Prof. Antonio Abate at the Helmholtz-Zentrum Berlin has designed a study to investigate this risk. They cooperated with plant scientists from the Fujian Agriculture and Forestry University, China, where the experiments were carried out, and with a group from the university of Naples, Italy.

The plant experts prepared contaminated soil samples with different concentrations of lead from either perovskite solar cells or other lead sources and cultivated different plants. After a growth period they analyzed the lead content in leafs and other parts of the plant. They found that lead from perovskite solar cells is ten time more bioavailable than lead from other industrial sources.

„And what's more, the uptake ability of lead increases with the concentration of perovskite in the soil", says Dr. Qiong Wang from Abate's team. This could be related to the fact that the organic cations in the perovskite change the PH content of the soil and thus promote the absorption of lead by the plants, she suggests. "These results show that we cannot consider perovskite as just another lead contaminant", Abate concludes.

Abate, who has obtained an European Research Grant, is working on the development of lead-free perovskite solar cells containing tin. Tin is also highly toxic, although it reacts very quickly to non-water-soluble forms. A series of experiments with mint plants on tin-contaminated soil showed that the plants absorb only a small amount of it. Lead-free perovskite solar cells, however, still fall short of the high efficiencies of lead-containing solar cells and also have even greater problems with stability.

The Helmholtz-Zentrum Berlin has huge expertise in the field of perovskite solar cells with or without lead. "We have to investigate this class of materials very broadly" Abate says: „Of course it is important to increase efficiencies and long time stability but we need as well to make sure that these materials do not pose a risk for the environment."

In the warmer and brighter shallow waters of Kāne'ohe Bay, O'ahu, the Hawaiian rice coral (Montipora capitata) hosts more heat-tolerant symbiotic microalgae in their tissues compared to corals in deeper waters. This pattern was demonstrated in a recent study by scientists at the University of Hawai'i (UH) at Mānoa School of Ocean and Earth Science and Technology (SOEST), and they suggest that while this can help corals weather a heat wave, it may have a price--lower nutrition when the heat wave has passed and seawater temperatures cool down.

Kāne'ohe Bay has experienced significant human impacts over the last century related to dredging, sewage pollution, and urbanization, in addition to regional bleaching events due to climate change. Despite this unique and troubled history, corals thrive in Kāne'ohe Bay. In some corals, this enhanced ability to tolerate environmental stress can in part be attributed to the species of microalgae corals harbor within their tissues.

Research over the last two decades has shown that coral's symbiotic algae are quite distinct, each group having different abilities and capacities to tolerate stress, like elevated seawater temperatures that cause coral bleaching.

"We wanted to know more about how these symbionts affected corals and whether trade offs existed for corals harboring different symbiont species," said Chris Wall, lead author of the study and postdoctoral researcher at SOEST's Pacific Biosciences Research Center.

Rice corals form partnerships with two distinct communities of symbiotic microalgae. Using genetic sequencing, the research team found that light availability is shaping the distribution of these symbiont communities in corals sampled from Kāne'ohe Bay, with the heat-tolerant symbionts being more common in shallow depths. Interestingly, although the heat-tolerant microalgae were present in much greater abundance inside the coral's tissues relative to other symbiont species, they were providing less energy to their shallow coral hosts.

Reef corals rely on two sources of energy: from their symbiotic microalgae that live harmoniously within the coral, and food in the surrounding water, such as microscopic shrimp-like animals.

"What was surprising was that corals did not compensate for less food from their symbionts by eating more food in the water column," said Wall. "This was a very cool finding, because we confirmed for the first time that the symbiont species living in corals were affecting nutrition in the field."

Together, the dark water and greater frequency of disturbances may have allowed stress-tolerant coral symbionts, thought to be more opportunistic and 'selfish', to proliferate within the local coral population. This study shows that while stress tolerance may be favorable during challenging periods, these symbionts provide less food to their corals, which may not be as beneficial to the corals in the long term.

"Climate change and ocean warming are changing the costs and benefits of these interactions between corals and their symbiont algae," said Wall. "As we consider techniques for assisting corals in their ability to tolerate environmental stress, our work highlights the need to consider how symbiont communities influence corals beyond stress tolerance. Our findings are also important for people in Kāne'ohe Bay, considering the corals with these stress-tolerant algae are found at higher abundance in the shallows. Any damage from anchors and boat-strikes could seriously harm these coral populations."

A UNSW study published today in Nature Communications presents an exciting step towards domain-wall nanoelectronics: a novel form of future electronics based on nano-scale conduction paths, and which could allow for extremely dense memory storage.

FLEET researchers at the UNSW School of Materials Science and Engineering have made an important step in solving the technology's primary long-standing challenge of information stability.

Domain walls are 'atomically sharp' topological defects separating regions of uniform polarisation in ferroelectric materials.

Domain walls in ferroelectrics possess fascinating properties, and are considered separate entities with properties that are dramatically different from the parent bulk ferroic material.

These properties are brought about by changes in structure, symmetry and chemistry confined within the wall.

"This is the fundamental starting point underpinning domain wall nanoelectronics," says study author Prof Jan Seidel.

The 'switching' property of ferroelectric materials makes them a popular candidate for low-voltage nanoelectronics. In a ferroelectric transistor, distinct polarisation states would represent the computational 0 and 1 states of binary systems.

However, the stability of that stored polarisation information has proven to be a challenge in application of the technology to data storage, especially for very small nanoscale domain sizes, which are desired for high storage densities.

"The polarisation state in ferroelectric materials decays typically within days to a few weeks, which would mean information storage failure in any domain-wall data storage system," says author Prof Nagy Valanoor.

The period of time that information can be stored in ferroelectric materials, ie the stability of the stored polarisation information, is thus a key performance feature.

To date, this long-standing issue of information instability has been one of the main limitations on the technology's application.

The study investigates the ferroelectric material BiFeO3 (BFO) with specially introduced designer defects in thin films. These designer defects can clamp down domain walls in the material, effectively preventing the ferroelectric domain relaxation process that drives information loss.

"We used a 'defect engineering' method to design and fabricate a special BFO thin film that is not susceptible to retention loss over time," says lead author Dr Daniel Sando.

VOLTAGE-DEPENDENT DOMAIN FORMATION

Pinning of domain walls is thus the main factor utilised to engineer very long polarisation retention.

"The novelty of this new research lies in precisely-controlled pinning of the domain wall, which allowed us to realise superior polarisation retention," says lead author Dawei Zhang.

The research provides critical new thinking and concepts for domain-wall based nanoelectronics for non-volatile data storage and logic device architectures.

In addition the mixed phase BFO-LAO system is a fertile ground for other intriguing physical properties, including piezoelectric response, field-induced strain, electrochromic effects, magnetic moments, electrical conductivity and mechanical properties.

Organic self-assembled monolayers (SAMs) have been around for over forty years. The most widely used form is based on thiols, bound to a metal surface. However, although the thiol SAMs are very versatile, they are also chemically unstable. Exposure of these monolayers to air will lead to oxidation and breakdown within a single day. University of Groningen scientists have now created SAMs using buckyballs functionalized with 'tails' of ethylene glycol. These molecules produce self-assembled monolayers that have all the properties of thiol SAMs but remain chemically unchanged for several weeks when exposed to air. This robustness makes them much easier to use in research and in devices. An article about these new SAMs was published in Nature Materials on 30 January.

Self-assembled monolayers are dynamic structures, explains University of Groningen Associate Professor of Organic-Materials Chemistry and Devices Ryan Chiechi: 'These monolayers self-repair and the molecules will continually find the most efficient packing. Furthermore, all processes are reversible, and it is possible to change their composition.' This distinguishes SAMs from other monolayers that are used to functionalize surfaces. 'These are often very stable, but they don't self-assemble and lack the dynamics of SAMs.'

Quantum tunneling

SAMs based on the binding of thiols (sulfur-containing groups) to metal are widely studied and used. Applications of SAMs range from the control of wetting of- or adhesion to surfaces, creating chemical resistance in lithography, to sensor production or nanofabrication. The monolayers can also be used to produce molecular electronics. Chiechi: 'Electric current will pass through such a monolayer by quantum tunneling. And small modifications to the molecular layer can alter the tunneling properties. Through such chemical tailoring, it is possible to create new types of electronics.'

However, the most widely used thiol-based SAMs are sensitive to oxidization when exposed to air. Without protection, they will not last a single day. 'This means that you need all kinds of equipment to keep the air out when working with these SAMs for molecular electronics,' explains Chiechi. 'It also makes it difficult to use them in a biological context.'

Functionalized buckyballs

This is where the new buckyball-based SAMs come in. In a joint effort, scientists from the Stratingh Institute for Chemistry and the Zernike Institute for Advanced Materials at the University of Groningen have discovered and characterized the properties of glycol-ether functionalized fullerenes. The buckyballs adhere to metal surfaces even stronger than thiols. The glycol-ether tails are polar and in organic solvents, this induces the formation of a bilayer. 'You simply put the metal in a solution of these functionalized buckyballs and the bilayer will form through self-assembly,' says Chiechi. Furthermore, SAMs prepared in this way are very resistant to oxidization: when left exposed to air, they will remain intact for at least 30 days.

'Our results strongly suggest that the tails of the molecules are intertwined. This results in a stable and very dynamic structure where molecules are free to move, which is typical for a SAM,' says Chiechi. The outer layer can be replaced by adding other functionalized groups. Chiechi and his colleagues added spiropyrans (molecules that will change shape when exposed to UV light) connected to a glycol-ether tail. By placing an electrode on the outer layer, tunneling through the SAM was measured. The scientists showed that changing the shape of the spiropyran moiety with light also changed the conductance by several orders of magnitude.

Molecular electronics

There are other alternatives for thiol-based SAMs but they all have limitations. 'We believe that our SAMs have all the properties of thiol-based SAMs, with resistance to degradation by air as a large bonus', concludes Chiechi. 'Furthermore, we have shown that our system can be used to create molecular electronics.' And it also appears to be a very useful platform for studying the behavior of SAMs. 'You can do this on your lab bench without any need for protection.' Chiechi thinks that his system might be useful for studying the behavior of bilayers, including the lipid bilayers that form cell membranes.

The ability to change the composition of the SAMs opens up interesting applications in molecular electronics. Chiechi: 'This might be used to create a topological computer architecture, for neuromorphic computing.' Changes in the composition of the SAM could produce a memristor and possibly a system for stochastic computing, which uses the probabilities of 1s and 0s to represent numbers in a bitstream. 'This could be represented by the fraction of one type of molecule in the SAM.' Before this can become a reality, however, more work will have to be done, for example, to understand why the glycol-ether phase is such an efficient tunneling medium.

"Yellow streaks in sunset sky, wind and daylong rain is nigh". This old world-widely weather proverb originates from aged fishermen by finding recognizable colors and shapes in clouds at sunset to predict an incoming storm. Nowadays, state-of-the-art satellites observations for tropical cyclone clouds structures, as well as the evolution of surrounding weather systems, are utilized to assist weather forecasters to make decisions. Indeed, rapid intensity changes often occur in conjunction with rapid reorganization of the tropical cyclone's mesoscale cloud and precipitation structures.

Super Typhoon Rammasun (2014) is the strongest-recorded TC at landfall over the Chinese mainland since 1949. By using satellite observations and high-resolution ensemble simulation output, Dr. Yihong Duan and his team--a group of researchers from the Hainan Key Laboratory of South China Sea Meteorological Disaster Prevention and Mitigation, the State Key Laboratory of Severe Weather, China Meteorological Administration, and the Australian Bureau of Meteorology--have had their findings about the precursors of Rammasun's onset of rapid intensification (RI) published in Advances in Atmospheric Sciences.

For the early RI onset member, strong ascent develops over the downshear flank at radii beyond the radius of maximum wind, merging inward-penetrating inner cloud bands that become deep convections while the vortex core becomes upright. Thus, the Synchronization Index, a simple measure of the amount of coherence in the vertical structure of the circulation, is proposed by Dr. Noel Davidson, one of the authors of the current study.

"The Synchronization Index presented here is a useful way of monitoring vortex structure, though it is only based upon our analysis of an ensemble of RI forecasts for one case study," says Dr. Duan. "We plan to extend the study by making further analyses and budget diagnoses from the members, to better understand the processes that influence RI."

Harvesting sunlight, researchers of the Center for Integrated Nanostructure Physics, within the Institute for Basic Science (IBS, South Korea) published in Materials Today a new strategy to transform carbon dioxide (CO2) into oxygen (O2) and pure carbon monoxide (CO) without side-products in water. This artificial photosynthesis method could bring new solutions to environmental pollution and global warming.

While, in green plants, photosynthesis fixes CO2 into sugars, the artificial photosynthesis reported in this study can convert CO2 into oxygen and pure CO as output. The latter can then be employed for a broad range of applications in electronics, semiconductor, pharmaceutical, and chemical industries. The key is to find the right high-performance photocatalyst to help the photosynthesis take place by absorbing light, convert CO2, and ensuring an efficient flow of electrons, which is essential for the entire system.

Titanium oxide (TiO2) is a well-known photocatalyst. It has already attracted significant attention in the fields of solar energy conversion and environmental protection due to its high reactivity, low toxicity, chemical stability, and low cost. While conventional TiO2 can absorb only UV light, the IBS research team reported previously two different types of blue-colored TiO2 (or "blue titania") nanoparticles that could absorb visible light thanks to a reduced bandgap of about 2.7 eV. They were made of ordered anatase/disordered rutile (Ao/Rd) TiO2 (called, HYL's blue TiO2-I) (Energy & Environmental Science, 2016), and disordered anatase/ordered rutile (Ad/Ro) TiO2 (called, HYL's blue TiO2-II) (ACS Applied Materials & Interfaces, 2019), where anatase and rutile refer to two crystalline forms of TiO2 and the introduction of irregularities (disorder) in the crystal enhances the absorption of visible and infra-red light.

For the efficient artificial photosynthesis for the conversion of CO2 into oxygen and pure CO, IBS researchers aimed to improve the performance of these nanoparticles by combining blue (Ao/Rd) TiO2 with other semiconductors and metals that can enhance water oxidation to oxygen, in parallel to CO2 reduction into CO only. The research team obtained the best results with hybrid nanoparticles made of blue titania, tungsten trioxide (WO3), and 1% silver (TiO2/WO3-Ag). WO3 was chosen because of the low valence band position with its narrow bandgap of 2.6 eV, high stability, and low cost. Silver was added because it enhances visible light absorption, by creating a collective oscillation of free electrons excited by light, and also gives high CO selectivity. The hybrid nanoparticles showed about 200 times higher performance than nanoparticles made of TiO2 alone and TiO2/WO3 without silver.

Starting from water and CO2, this novel hybrid catalyst produced O2 and pure CO, without any side products, such as hydrogen gas (H2) and metane (CH4). The apparent quantum yield that is the ratio of several reacted electrons to the number of incident photons was 34.8 %, and the rate of reacted electrons 2333.44 μmol g?1h?1. The same measurement was lower for nanoparticles without silver (2053.2 μmol g?1h?1), and for nanoparticles with only blue TiO2 (912.4 μmol g?1h?1). "We expect these results will help the industry-scaled CO2 reduction and produce oxygen and commercially available CO derivatives," says Hyoyoung Lee, CINAP associate director.

Osaka, Japan - A team including researchers from Osaka University has produced a new molecular emitter for organic light-emitting diodes (OLEDs). Using rational chemical design with U-shaped synthetic building blocks, the scientists were able to arrange the electron donors and acceptors into a large ring called a "macrocycle." The wheel-shaped molecule could potentially be used not only in OLEDs but also in tiny, energy-efficient chemical sensors in the future.

Many modern televisions and smartphones use OLEDs to display pictures and videos. These devices can efficiently convert electricity into light because they are made from carbon-based molecules containing alternating single and double chemical bonds, an arrangement called π-conjugation. This configuration allows electrons to become highly mobile because they are effectively "delocalized" over large regions of the molecules, which tend to be long linear chains. When a molecule is electronically excited by external energy and then relaxes to the original state, the excess energy can be converted directly into light. By adding the right chemical functional groups to the molecule, a whole range of properties, such as emission colors and energy conversion efficiencies, can be fine-tuned.

Now, a research team led by Professor Youhei Takeda at Osaka University has designed and synthesized an efficient macrocyclic OLED emitter in which donor and acceptor regions alternate in a permanently bonded ring structure. They found that OLED devices fabricated with the new macrocyclic emitter show much better efficiencies compared with linear molecular emitters (which act like open forms of the macrocycles), due to the fact that the macrocycles can more efficiently harvest ambient heat energy in a process called "thermally activated delayed fluorescence."

"Linear π-conjugated oligomers and polymers already play crucial roles in materials science, but we found ring-shaped macrocycles to be even better for many applications," says first author Saika Izumi. The team was able to create two different conformations, "saddle" and "helical", with different packing arrangements and emission colors. The nanoscale cavities inside the rings can be designed to interact with target molecules to create efficient and selective chemical sensors.

"Macrocycles can be arranged into highly-ordered 2D- and 3D-molecular assemblies that are much more difficult to achieve with linear analogs," explains senior author Youhei Takeda.

Possible future applications include the detection of chemical substances, such as water molecules or gases, based on the modulation of light emitted when the target substance is present inside the cavity.

Australia's devastating drought is having a critical impact on the iconic platypus, a globally unique mammal, with increasing reports of rivers drying up and platypuses becoming stranded.

Platypuses were once considered widespread across the eastern Australian mainland and Tasmania, although not a lot is known about their distribution or abundance because of the species' secretive and nocturnal nature.

A new study led by UNSW Sydney's Centre for Ecosystem Science, funded through a UNSW-led Australian Research Council project and supported by the Taronga Conservation Society, has for the first time examined the risks of extinction for this intriguing animal.

Published in the international scientific journal Biological Conservation this month, the study examined the potentially devastating combination of threats to platypus populations, including water resource development, land clearing, climate change and increasingly severe periods of drought.

Lead author Dr Gilad Bino, a researcher at the UNSW Centre for Ecosystem Science, said action must be taken now to prevent the platypus from disappearing from our waterways.

"There is an urgent need for a national risk assessment for the platypus to assess its conservation status, evaluate risks and impacts, and prioritise management in order to minimise any risk of extinction," Dr Bino said.

Alarmingly, the study estimated that under current climate conditions and due to land clearing and fragmentation by dams, platypus numbers almost halved, leading to the extinction of local populations across about 40 per cent of the species' range, reflecting ongoing declines since European colonisation.

Under predicted climate change, the losses forecast were far greater because of increases in extreme drought frequencies and duration, such as the current dry spell.

Dr Bino added: "These dangers further expose the platypus to even worse local extinctions with no capacity to repopulate areas."

Documented declines and local extinctions of the platypus show a species facing considerable risks, while the International Union for Conservation of Nature (IUCN) recently downgraded the platypus' conservation status to "Near Threatened".

But the platypus remains unlisted in most jurisdictions in Australia - except South Australia, where it is endangered.

Director of the UNSW Centre for Ecosystem Science and study co-author Professor Richard Kingsford said it was unfortunate that platypuses lived in areas undergoing extensive human development that threatened their lives and long-term viability.

"These include dams that stop their movements, agriculture which can destroy their burrows, fishing gear and yabby traps which can drown them and invasive foxes which can kill them," Prof Kingsford said.

Study co-author Professor Brendan Wintle at The University of Melbourne said it was important that preventative measures were taken now.

"Even for a presumed 'safe' species such as the platypus, mitigating or even stopping threats, such as new dams, is likely to be more effective than waiting for the risk of extinction to increase and possible failure," Prof Wintle said.

"We should learn from the peril facing the koala to understand what happens when we ignore the warning signs."

Dr Bino said the researchers' paper added to the increasing body of evidence which showed that the platypus, like many other native Australian species, was on the path to extinction.

"There is an urgent need to implement national conservation efforts for this unique mammal and other species by increasing monitoring, tracking trends, mitigating threats, and protecting and improving management of freshwater habitats," Dr Bino said.

The platypus research team is continuing to research the ecology and conservation of this enigmatic animal, collaborating with the Taronga Conservation Society, to ensure its future by providing information for effective policy and management.

A team of scientists from the Research and Education Center "Functional Nanomaterials" of Kant Baltic State University works on the development of new prospective nanomaterials. Together with foreign colleagues they have recently discovered a method for synthesizing titanium oxide (Ti2O3) thin films. Some of the new materials are considerably different from their bulk analogs and show the required conductivity within a wider range of temperatures. In the future they may be used to create effective catalysts that would not depend on temperature. The results of the study were published in the Thin Solid Films journal.

Some titanium oxides are known for their unique properties, such as increased photocatalytic activity (i.e. they effectively use light to speed up chemical reactions). Titanium oxide-based coatings are able to clean themselves under the influence of light. Moreover, they can potentially be used to purify air and water from harmful substances and to desalinate sea water. The same property has recently been found in nanomaterials based on titanium oxide (III). Among other things, titanium oxide (III) is able to change phase from a semiconductor to a metal. In the course of such a phase change it considerably increases its electrical conductivity when heated. Not only the level of conductivity, but even the relative position of atoms is subject to changing. One of the main goals of modern science is to look for structure-property patterns of this kind.

In this work the authors used the magnetron sputtering method to obtain thin titanium oxide films. In other words, the scientists bombarded a titanium target with charged particles. The ablated atoms were deposited on a special substrate and reacted with free oxygen radicals that were formed when oxygen molecules collided with the charged particles. As a result of this reaction thin oxide films were formed. Based on different oxygen concentrations and substrate temperatures, the scientists managed to obtain TiO, Ti2O3 and TiO2 oxides and among them - two completely different Ti2O3 structures that differed by the positions of atoms in the crystal lattice. One had a trigonal lattice similar to that of corundum, and the other one - an orthorhombic lattice that was obtained in its pure form. To do so, the scientists modified the sputtering method by using titanium oxide instead of titanium metal to ablate atoms in a completely oxygenless environment.

The scientists studied the properties of different types of titanium oxide (III) and discovered differences between the orthorhombic film produced by magnetron sputtering and another one described in 2017. The film created by the team remained a semiconductor within the whole range of described temperatures (from -268°? to 300°?) while the previously known structure became a conductor at temperatures above 100?? and a superconductor at temperatures close to absolute zero (below -265°?). It also turned out that the conductivity of the corundum-type film was similar to that of a bulk Ti2O3 heated to 170-200°?. At these temperatures the bulk gains metal properties, while the film preserved high conductivity within the range from -268°? to several hundred degrees Celsius.

"Compared to already known structures manufactured using other methods, our films maintain their properties within a wider range of temperatures. Thus, the corundum-type film remains a metal conductor at low temperatures, and the orthorhombic film - a semiconductor at high temperatures," said Petr Shvets, a Candidate of Physics and Mathematics, and a senior researcher at the Research and Education Center "Functional Nanomaterials".

Arctic sea ice cannot "quickly bounce back" if climate change causes it to melt, new research suggests.

A team of scientists led by the University of Exeter used the shells of quahog clams, which can live for hundreds of years, and climate models to discover how Arctic sea ice has changed over the last 1,000 years.

They found sea ice coverage shifts over timescales of decades to centuries - so shrinking ice cannot be expected to return rapidly if climate change is slowed or reversed.

The study examined whether past ice changes north of Iceland were "forced" (caused by events such as volcanic eruptions and variations in the sun's output) or "unforced" (part of a natural pattern).

At least a third of past variation was found to be "forced" - showing the climate system is "very sensitive" to such driving factors, according to lead author Dr Paul Halloran, of the University of Exeter.

"There is increasing evidence that many aspects of our changing climate aren't caused by natural variation, but are instead 'forced' by certain events," he said.

"Our study shows the large effect that climate drivers can have on Arctic sea ice, even when those drivers are weak as is the case with volcanic eruptions or solar changes.

"Today, the climate driver isn't weak volcanic or solar changes - it's human activity, and we are now massively forcing the system."

Co-author of the study Professor Ian Hall, from Cardiff University, said: "Our results suggest that climate models are able to correctly reproduce the long-term pattern of sea ice change.

"This gives us increased confidence in what climate models are telling us about current and future sea ice loss."

When there is lots of sea ice, some of this drifts southwards and, by releasing fresh water, can slow the North Atlantic Ocean circulation, otherwise known as the Atlantic Meridional Overturning Circulation (AMOC).

The AMOC brings warm water from the tropics towards the Arctic, so slowing it down cools this region and allows sea ice to grow further.

So, with less ice the AMOC can bring in more warm water - a so-called "positive feedback" where climate change drives further warming and sea ice loss.

Quahog clams are thought to be the longest-living non-colonial animal on Earth, and their shells produce growth rings which can be examined to measure past environmental changes.

Dr Halloran is part of the Global Systems Institute, which brings together experts from a wide range of fields to find solutions to global challenges.

The new study is part of a project including Cardiff University, the Met Office and an international team working on climate model simulations of the last millennium. The work was funded by the Natural Environment Research Council.

January 21, 2020 - Washington, DC - A new study recently published in Nutrients, a peer-reviewed medical journal of human nutrition, highlights the importance of grains as part of a healthy infant diet - and the potential risks of excluding them.

Undertaken to inform the development of the first-ever Dietary Guidelines for Americans (2020-2025) to include specific recommendations for infants and toddlers, the study analyzed infant data from the 2001-2016 National Health and Nutrition Examination Survey (NHANES) to assess grain food relationships with nutrient and energy intakes, diet quality, and food group consumption in infant grain consumers relative to non-consumers.

"This study is the first to examine grain consumption patterns among U.S. infants using NHANES and clearly provides evidence for what organizations, including the American Academy of Pediatrics and the CDC, have been suggesting for decades: grains support the backbone of a healthy infant diet," says study author Yanni Papanikolaou, MPH, of Nutritional Strategies Inc. "In addition, the study highlights the many potential long-term nutrition-related health risks of eliminating or reducing grain foods from diets during one of the most crucial stages of growth and development."

The study found grain consumption was generally associated with higher nutrient intakes, better diet quality scores and broader food group intake. Specifically:

Energy and Nutrients

6- to 12-months-old infants had significantly higher dietary fiber, calcium, folate, potassium, magnesium, zinc, phosphorus, choline, thiamin, riboflavin, and vitamin B6 compared to non-consumers.

13- to 23-month-olds had greater daily dietary fiber, iron, zinc, magnesium, phosphorus, folate, riboflavin, niacin, thiamin, vitamin A, vitamin B6, and vitamin B12 relative to non-consumers.

Diet Quality Scores

Scores were significantly higher in all infant grain consumers examined in comparison to non-consumers.

Younger grain-consuming infants typically ate more greens and beans, total fruit, whole grains, refined grains, dairy foods, total protein foods, seafood and plant protein foods, and saturated fat in comparison to non-consumers of grains.

Older infants consuming grains typically ate more total fruit, whole fruit, whole grains, and refined grains relative to non-consumers.

Food Group Intake

Grain intake was linked with greater daily intake of several recommended food groups in both younger and older infants versus non-consumption of grains.

Infants 6-12-months-old had significantly higher intakes of milk, cheese, and total dairy foods compared to grain non-consumers.

Infant grain consumption was linked to higher refined and whole grain intake, as well as greater intake in terms of total fruits, total vegetables and total meat, poultry, seafood, nuts and seeds compared to non-consumers of grains.

Papanikolaou notes that the study included both whole grains and refined grains, as defined by the USDA Food Patterns Equivalents Database, in its analysis.

Taking a broad look at the data, he explains that while grains can be contributors of sugar and sodium to children's' diets, certain grain foods contribute high-value nutrient density that surpasses caloric contributions in the diet. As the American Academy of Pediatrics' "whole diet approach" suggests, these foods can be made more palatable by adding small amounts of sugar, fat and sodium (for example, putting a bit of brown sugar on oatmeal).

As Papanikolaou concludes, early acceptance and familiarity with nutrient-dense whole grain and fortified or enriched refined grain foods (as opposed to "indulgent grains") will likely help close nutrient intake recommendation gaps as children grow and develop - with particular emphasis on shortfall nutrients such as dietary fiber, folate, magnesium, calcium, and iron.

"The key takeaway of this study is that parents, caregivers, and those who provide them nutritional guidance need to know the many benefits of including, and the many risks of excluding, grains in infants' diets," concludes Papanikolaou.

The new published study in Nutrients can be found here.

The Grain Foods Foundation provided funding support for this research. For more information about the research findings, and to learn more about grain foods' role in a healthful diet, please visit http://www.GrainFoodsFoundation.org.

The discovery last year of the first nickel oxide material that shows clear signs of superconductivity set off a race by scientists around the world to find out more. The crystal structure of the material is similar to copper oxides, or cuprates, which hold the world record for conducting electricity with no loss at relatively high temperatures and normal pressures. But do its electrons behave in the same way?

The answers could help advance the synthesis of new unconventional superconductors and their use for power transmission, transportation and other applications, and also shed light on how the cuprates operate - which is still a mystery after more than 30 years of research.

In a paper published today in Nature Materials, a team led by scientists at the Department of Energy's SLAC National Accelerator Laboratory and Stanford University report the first detailed investigation of the electronic structure of superconducting nickel oxides, or nickelates.

The scientists used two techniques, resonant inelastic X-ray scattering (RIXS) and X-ray absorption spectroscopy (XAS), to get the first complete picture of the nickelates' electronic structure - basically the arrangement and behavior of their electrons, which determine a material's properties.

Both cuprates and nickelates come in thin, two-dimensional sheets that are layered with other elements, such as rare-earth ions. These thin sheets become superconducting when they're cooled below a certain temperature and the density of their free-flowing electrons is adjusted in a process known as "doping."

Cuprates are insulators in their pre-doped "ground" states, meaning that their electrons are not mobile. After doping the electrons can move freely but they are mostly confined to the cuprate layers, rarely traveling through the intervening rare-earth layers to reach their cuprate neighbors.

But in the nickelates, the team discovered, this is not the case. The undoped compound is a metal with freely flowing electrons. Furthermore, the intervening layers actually contribute electrons to the nickelate sheets, creating a three-dimensional metallic state that is quite different from what's seen in the cuprates.

This is an entirely new type of ground state for transition metal oxides such as cuprates and nickelates, the researchers said. It opens new directions for experiments and theoretical studies of how superconductivity arises and how it can be optimized in this system and possibly in other compounds.

A study funded by the Veterans Administration and directed by researchers at the University of Miami Miller School of Medicine has shown few differences in the profiles of genes that influence cognition between people with schizophrenia, bipolar disorder and the general population. This surprising finding could provide new insights into therapies designed to improve cognition. The study was published in the American Journal of Medical Genetics.

"For years, people have been talking about cognition in schizophrenia and bipolar disorder and how cognitive impairments in these apparently distinct conditions are likely qualitatively different from each other, as well as qualitatively different from what's going on in the general population," said lead author Philip D. Harvey, Ph.D., professor of psychiatry and behavioral sciences. "What we find here is that the biggest signal is normal. The genomics of cognition in the general population appears to be driving all these other findings."

The study assessed more than 9,000 veterans with schizophrenia and bipolar disorder. In addition to analyzing genomic data, the research team went much deeper than previous efforts, confirming participants' diagnoses and giving them cognitive tests. This is the largest study in mental health conditions to combine genome-wide association methods with cognitive assessments.

"Our study is small by comparison - some of the previous studies had 1.2 million people in them," said Dr. Harvey. "But it is completely different in that we personally saw every research participant. The others are all essentially database studies."

In addition, by validating the genomics with actual cognitive testing, the VA/Miller School team has added new context to these large database projects, giving researchers robust cognitive data to better analyze the results from multiple studies with different methods.

Learning that the genomics of cognition for schizophrenia, bipolar disorder and the general population have substantial overlap also provides new clues to improve therapies.

"If you know what the genomics are, you can start considering gene therapies," said Dr. Harvey. "You can also start understanding whether cognitive impairments in schizophrenia and bipolar disorder are essentially an exaggerated case of normal variation."

This could have an almost immediate impact on patients with severe mental illness. Because the structure and genetic determinants for cognition vary so little between the different illnesses, as well as the general population, assessment and intervention strategies that are proven in schizophrenia may be applicable to people with bipolar disorder and vice versa.

"You may not need specialized assessments for cognition in schizophrenia or bipolar disorder, and you may not need different treatments either," said Dr. Harvey. "We should be pursuing treatment options for people with schizophrenia and bipolar disorder to treat cognitive impairment that are not necessarily different from each other. And we should be doing assessments that differ only in their level of difficulty, not qualitatively different assessments."

London - A project taking the first steps towards ending the use of horses to treat diphtheria has succeeded.

Funded by the PETA International Science Consortium Ltd. and carried out at the Institute of Biochemistry, Biotechnology, and Bioinformatics at the Technische Universität Braunschweig in Germany, the project created human antibodies capable of blocking the poisonous toxin that causes diphtheria. The results were published Friday in Scientific Reports (a Nature research journal).

Diphtheria is a potentially deadly infectious disease causing severe respiratory distress and damage to vital organs and is a significant human health burden. For more than 100 years, the main method of producing the antitoxin to treat it has been to inject horses repeatedly with the diphtheria toxin and then drain them of huge amounts of their blood in order to collect the antibodies that their immune systems produce to fight the disease. This animal-derived antitoxin has the potential to cause serious allergic reactions in humans, and global health authorities report having difficulty acquiring sufficient stockpiles of these antitoxins to respond quickly to diphtheria outbreaks.

Inspections of facilities where horses are used to produce animal-derived antitoxins have found widespread neglect of animal welfare regulations, with horses confined to filthy, severely crowded enclosures and suffering from anaemia, diseased hooves, eye abnormalities, infections, parasites, and malnutrition.

Rather than using horses, the researchers involved in this project used human blood cells to create human antibodies that block the diphtheria toxin. The Science Consortium is now working with its research partners to ensure that the non-animal antitoxin is developed into a medicine that will be used to treat this menacing disease more reliably and safely without causing a single horse to suffer.

"Thousands of horses worldwide are forced to endure cruel treatment for the production of many different types of drugs, not just diphtheria antitoxin," says Jeffrey Brown, adviser to the PETA International Science Consortium and co-author of the paper. "Solid science has now given these horses a way out of this suffering."

CINCINNATI--Yes, fat cells deep under your skin can sense light. And when bodies do not get enough exposure to the right kinds of light, fat cells behave differently.

This discovery, published Jan. 21, 2020, in the journal Cell Reports, was uncovered by scientists at Cincinnati Children's who were studying how mice control their body temperature. What they found has implications far beyond describing how mice stay warm.

The study shows that light exposure regulates how two kinds of fat cells work together to produce the raw materials that all other cells use for energy. The study authors go on to say that disruptions to this fundamental metabolic process appear to reflect an unhealthy aspect of modern life--spending too much time indoors.

"Our bodies evolved over the years under the sun's light, including developing light-sensing genes called opsins," says Richard Lang, PhD, a developmental biologist and senior author of the study. "But now we live so much of our days under artificial light, which does not provide the full spectrum of light we all get from the sun."

Lang directs the Visual Systems Group at Cincinnati Children's and has authored or co-authored more than 120 research papers, including many related to eye development and how light interacts with cells beyond the eye.

"This paper represents a significant change in the way we view the effects of light on our bodies," Lang says.

Shining new light on the role of light

Many people understand that certain wavelengths of light can be harmful, such as gamma radiation from a nuclear bomb or too much ultraviolent light from the sun burning our skin. This study from Lang and colleagues describes a different, healthy role for light exposure.

Despite the fur of a mouse, or the clothing of a person, light does get inside our bodies. Photons--the fundamental particles of light--may slow down and scatter around once they pass the outer layers of skin, Lang says. But they really do get in, and when they do, they affect how cells behave.

Lang's work in this direction dates back to 2013, when he led a study published in Nature, that demonstrated how light exposure affected eye development in fetal mice. More recently, in 2019, Lang and colleagues published two more papers, one in April in Nature Cell Biology that reported possible benefits of light therapy for eye development in preterm infants, and another study in October in Current Biology that details how light receptors in the skin help mice regulate their internal clocks.

The new study in Cell Reports includes important contributions from Russell Van Gelder, MD, PhD, and Ethan Buhr, PhD, from the University of Washington, and Randy Seeley, PhD, University of Michigan.

"This idea of light penetration into deep tissue is very new, even to many of my scientific colleagues," Lang says. "But we and others have been finding opsins located in a variety of tissue types. This is still just the beginning of this work."

How light ignites an internal fire

In the latest findings, the research team studied how mice respond when exposed to chilly temperatures--about 40° F. They already knew that mice, much like humans, use both a shivering response and an internal fat-burning response to heat themselves.

Deeper analysis revealed that the internal heating process is compromised in the absence of the gene OPN3 and exposure specifically to a 480-nanometer wavelength of blue light. This wavelength is a natural part of sunlight but occurs only in low levels in most artificial light.

When the light exposure occurs, OPN3 prompts white fat cells to release fatty acids into the bloodstream. Various types of cells can use these fatty acids as energy to fuel their activities. But brown fat literally burns the fatty acids (in a process called oxidation) to generate heat that warms up the chilly mice.

When mice were bred to lack the OPN3 gene, they failed to warm up as much as other mice when placed in chilly conditions. But surprisingly, even mice that had the correct gene failed to warm up when they exposed to light that lacked the blue wavelength.

This data prompted the team to conclude that sunlight is required for normal energy metabolism. At least in mice. While the scientists strongly suspect that a similar light-dependent metabolic pathway exists in humans, they need to complete another series of experiments to prove it.

"If the light-OPN3 adipocyte pathway exists in humans, there are potentially broad implications for human health," the study states. "Our modern lifestyle subjects us to unnatural lighting spectra, exposure to light at night, shift work, and jet lag, all of which result in metabolic disruption. Based on the current findings, it is possible that insufficient stimulation of the light-OPN3 adipocyte pathway is part of an explanation for the prevalence of metabolic deregulation in industrialized nations where unnatural lighting has become the norm."

What's next?

It likely will require several years of study to flesh out this discovery.

Someday, in theory, "light therapy" could become a method for preventing metabolic syndrome from developing into diabetes. Replacing indoor lights with better, full-spectrum lighting systems also could improve public health, Lang says.

However, more study is needed to pin down the potential therapeutic value of light therapy. Questions to answer include determining how much sunlight is needed to support a healthy metabolism and whether people battling obesity might lack a functional OPN3 gene in their fat cells. Also unknown: when would light therapy matter most: for pregnant mothers? For infants and children? Or for fully developed adults?

For now, however, "if people want to take anything personal away from this, you likely can't go wrong by spending more time outside," Lang says.