As the demand for smartphones, electric vehicles, and renewable energy continues to rise, scientists are searching for ways to improve lithium-ion batteries — the most common type of battery found in home electronics and a promising solution for grid-scale energy storage. Increasing the energy density of lithium-ion batteries could facilitate the development of advanced technologies with long-lasting batteries, as well as the widespread use of wind and solar energy.
A collaboration led by scientists at the University of Maryland (UMD), the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory, and the U.S. Army Research Lab have developed and studied a new cathode material that could triple the energy density of lithium-ion battery electrodes.
“Lithium-ion batteries consist of an anode and a cathode,” said Xiulin Fan, a scientist at UMD and one of the lead authors of the paper. “Compared to the large capacity of the commercial graphite anodes used in lithium-ion batteries, the capacity of the cathodes is far more limited. Cathode materials are always the bottleneck for further improving the energy density of lithium-ion batteries.”
Scientists at UMD synthesized a new cathode material, a modified and engineered form of iron trifluoride (FeF3), which is composed of cost-effective and environmentally benign elements — iron and fluorine. Researchers have been interested in using chemical compounds like FeF3 in lithium-ion batteries because they offer inherently higher capacities than traditional cathode materials.
“The materials normally used in lithium-ion batteries are based on intercalation chemistry,” said Enyuan Hu, a chemist at Brookhaven and one of the lead authors of the paper. “This type of chemical reaction is very efficient; however, it only transfers a single electron, so the cathode capacity is limited. Some compounds like FeF3 are capable of transferring multiple electrons through a more complex reaction mechanism, called a conversion reaction.”
Despite FeF3’s potential to increase cathode capacity, the compound has not historically worked well in lithium-ion batteries due to three complications with its conversion reaction: poor energy efficiency (hysteresis), a slow reaction rate, and side reactions that can cause poor cycling life. To overcome these challenges, the scientists added cobalt and oxygen atoms to FeF3 nanorods through a process called chemical substitution. This allowed the scientists to manipulate the reaction pathway and make it more “reversible.”
“When lithium ions are inserted into FeF3, the material is converted to iron and lithium fluoride,” said Sooyeon Hwang, a co-author of the paper and a scientist at Brookhaven’s Center for Functional Nanomaterials (CFN). “However, the reaction is not fully reversible. After substituting with cobalt and oxygen, the main framework of the cathode material is better maintained and the reaction becomes more reversible.”
To investigate the reaction pathway, the scientists conducted multiple experiments at CFN and the National Synchrotron Light Source II (NSLS-II) — two DOE Office of Science User Facilities at Brookhaven.
First at CFN, the researchers used a powerful beam of electrons to look at the FeF3 nanorods at a resolution of 0.1 nanometers — a technique called transmission electron microscopy (TEM). The TEM experiment enabled the researchers to determine the exact size of the nanoparticles in the cathode structure and analyze how the structure changed between different phases of the charge-discharge process. They saw a faster reaction speed for the substituted nanorods.
“TEM is a powerful tool for characterizing materials at very small length scales, and it is also able to investigate the reaction process in real time,” said Dong Su, a scientist at CFN and a co-corresponding author of the study. “However, we can only see a very limited area of the sample using TEM. We needed to rely on the synchrotron techniques at NSLS-II to understand how the whole battery functions.”
At NSLS-II’s X-ray Powder Diffraction (XPD) beamline, scientists directed ultra-bright x-rays through the cathode material. By analyzing how the light scattered, the scientists could “see” additional information about the material’s structure.
“At XPD, we conducted pair distribution function (PDF) measurements, which are capable of detecting local iron orderings over a large volume,” said Jianming Bai, a co-author of the paper and a scientist at NSLS-II. “The PDF analysis on the discharged cathodes clearly revealed that the chemical substitution promotes electrochemical reversibility.”
Combining highly advanced imaging and microscopy techniques at CFN and NSLS-II was a critical step for assessing the functionality of the cathode material.
“We also performed advanced computational approaches based on density functional theory to decipher the reaction mechanism at an atomic scale,” said Xiao Ji, a scientist at UMD and co-author of the paper. “This approach revealed that chemical substitution shifted the reaction to a highly reversible state by reducing the particle size of iron and stabilizing the rocksalt phase.”Scientists at UMD say this research strategy could be applied to other high energy conversion materials, and future studies may use the approach to improve other battery systems.
Local conservation actions, like rounding up predatory snails, can significantly boost the resilience of corals to climate-induced bleaching.
The study, comes at a time when scientists are deeply divided over whether local efforts to protect and manage coral reefs are enough to help stem the global tide of thermal bleaching that’s decimating corals worldwide as ocean temperatures continue to warm.
To test whether local actions can make a difference, the Duke-led team focused on one threat to reefs that is often controlled by local managers — populations of coral-eating animals like snails and starfish that have become too abundant.
“At high densities, these coral-eating animals, or ‘corallivores’, can cause low-grade but chronic stress to corals. Some of them are like Dracula, constantly sucking the energetic reserves out of corals and leaving them less equipped to deal with harsh environmental conditions like extreme warm temperatures and bleaching,” said Elizabeth Shaver, a 2018 doctoral graduate of Duke’s Nicholas School of the Environment, who is now a coral restoration scientist with The Nature Conservancy’s Reef Resilience Program.
To get a global sense of how managers deal with this threat, the researchers surveyed more than 30 coral reef management agencies worldwide, finding that many agencies reduce local corallivore populations in their sites. The researchers then mimicked managers by manually removing a voracious and common coral-eating snail from corals in the Florida Keys during a three-month spike in ocean temperatures in 2014. That warmup caused widespread coral bleaching across much of the eastern Caribbean and Gulf of Mexico.
The researchers focused their efforts on brain corals, which were found in a survey of six corals reefs in the Florida Keys to be particularly susceptible to predation by the snail.
“The idea was to see if removing these snails helped corals withstand and recover from warm temperatures and bleaching compared with corals that had average or naturally high densities of snails. And it did.”
“When snails were removed, corals experienced only 50 percent bleaching. Corals that still had high snail densities experienced near 100 percent,” Shaver said.
“We found that if a coral experienced only mild to moderate bleaching, as they did when snails were removed, it recovered almost completely,” said Brian Silliman, Rachel Carson Associate Professor of Marine Conservation Biology at Duke’s Nicholas School of the Environment.
“But if it experienced severe bleaching like the corals with high snail densities, tissue recovery was reduced by more than 80 percent,” Silliman said. “Some of these corals completely died, turning into algae-covered underwater basketballs. Removing or reducing the populations of snails played an important role in determining these outcomes.”
The new findings challenge several recent large-scale analyses arguing that local impacts and management have little effect in protecting reefs from climate-induced bleaching, Silliman said.
“Tens of millions of dollars have been invested in local coral reef conservation over the last 40 years. But more and more people are now saying we should end this approach and instead put most of our money into global efforts to reduce greenhouse gas emissions because there’s no evidence that local actions are making enough of a difference,” he said.
“These new findings reopen the discussion and provide a ray of hope for corals by showing that local interventions do make a difference.”
“Very few local interventions have been tested for their ability to enhance coral reef resilience,” Shaver said. “We found one simple solution by reducing coral predation stress, which can be done through removals or possibly in marine protected areas where studies show coral-eating invertebrates are naturally less abundant.”
The findings may also be important because the world’s climate is projected to continue changing even if carbon emissions were drastically reduced today.
“We need conservation dollars for both global and local efforts,” said Shaver, “so we can identify other resilience-enhancing approaches and arm local managers with tools to protect their reefs and resources.”
Constructing biological tissues, such as skin, muscle, or bone, in customized shapes is now one step closer. Researchers at EMBL have succeeded in guiding the folding and thus shape of tissues with optogenetics: a technique to control protein activity with light.
The changing of tissue shapes in an embryo is essential for healthy development. Stefano De Renzis and his group members at EMBL are interested in the mechanisms behind these shape transitions, also called morphogenesis. They use optogenetics — a technique providing precise light-mediated control of protein activity — to study changes in tissue shapes.
Uncoupling the link between shape and function
In the current paper, Emiliano Izquierdo, Theresa Quinkler, and Stefano De Renzis used optogenetics to reconstruct epithelial folding: a fundamental process during development, where cells move inwards and fold into the embryo, eventually giving rise to internal tissues like muscles, for example. Remarkably, they achieved this in cells that normally do not undergo this process. De Renzis, who led the study: “We’ve uncoupled the link between the shape and function of a cell. This allows us to, for the first time, built tissues in certain shape without affecting the cell’s expertise.”
“The great thing about using optogenetics to guide morphogenesis is that it is a very precise technique,” says Emiliano Izquierdo, first author of the study. “We were able to define various shapes, and by alternating the timing and strength of illumination, we could control how far the cells folded inwards.”
From fruit fly to the clinic?
The research was done in developing fruit flies, but since epithelial folding is a conserved process across evolution, De Renzis expects these methods to also be applicable in other organisms and ex vivo stem cell culture systems. In that case, optogenetics could be an ideal technique for reconstructing and directing tissue development, which could be used to (re)build artificial tissues in regenerative medicine.
Daily fasting is an effective tool to reduce weight and lower blood pressure.The study is the first to examine the effect of time-restricted eating — a form of fasting that limits food consumption to select hours each day — on weight loss in obese individuals.
To study the effect of this type of diet, researchers worked with 23 obese volunteers who had an average age of 45 and average body mass index, or BMI, of 35.
Between the hours of 10 a.m. and 6 p.m. the dieters could eat any type and quantity of food they desired, but for the remaining 16 hours they could only drink water or calorie-free beverages. The study followed the participants for 12 weeks.
When compared to a matched historical control group from a previous weight loss trial on a different type of fasting, the researchers found that those who followed the time-restricted eating diet consumed fewer calories, lost weight and had improvements in blood pressure. On average, participants consumed about 350 fewer calories, lost about 3 percent of their body weight and saw their systolic blood pressure decreased by about 7 millimeters of mercury (mm Hg), the standard measure of blood pressure. All other measures, including fat mass, insulin resistance and cholesterol, were similar to the control group.
“The take-home message from this study is that there are options for weight loss that do not include calorie counting or eliminating certain foods,” said Krista Varady, associate professor of kinesiology and nutrition in the UIC College of Applied Health Sciences and corresponding author on the study.
While this is the first study to look at the 16:8 diet, named for its 16 hours of fasting and its 8 hours of “feasting,” Varady says that the results align with previous research on other types of intermittent fasting diets.
“The results we saw in this study are similar to the results we’ve seen in other studies on alternate day fasting, another type of diet,” Varady said, “but one of the benefits of the 16:8 diet may be that it is easier for people to maintain. We observed that fewer participants dropped out of this study when compared to studies on other fasting diets.”
Varady says that while the research indicates daily fasting works for weight loss, there have not yet been studies to determine if it works better than other diets, although the researchers observed the weight loss to be slightly less than what has been observed in other intermittent fasting diet studies.
“These preliminary data offer promise for the use of time-restricted feeding as a weight loss technique in obese adults, but longer-term, large-scale randomized controlled trials [are required],” Varady and her colleagues write.
“The 16:8 diet is another tool for weight loss that we now have preliminary scientific evidence to support,” Varady said. “When it comes to weight loss, people need to find what works for them because even small amounts of success can lead to improvements in metabolic health.”
The Centers for Disease Control and Prevention estimates that more than one-third of adults in the U.S. have obesity, which greatly increases the risk of metabolic diseases such as coronary heart disease and Type 2 diabetes, and that obesity is most prevalent among non-Hispanic black individuals and middle-age adults.
Past studies have shown that biparental care of offspring can be affected negatively when females and males are exposed to bisphenol A (BPA); however, previous studies have not characterized how long-term effects of BPA exposure in grandmothers and grandfathers might affect offspring communication ability. researchers at the University of Missouri found that mice pups whose grandparents had been exposed to BPA, had different vocalization patterns. This, in turn, could also affect the amount of parental care they received. Scientists believe results could have important relevance to humans.
“Rodent pups use vocalizations to communicate with one or both parents, as in the case of biparental species, such as California mice,” said Cheryl Rosenfeld, professor of biomedical sciences in the College of Veterinary Medicine, investigator in the Bond Life Sciences Center, and research faculty member for the Thompson Center for Autism and Neurobehavioral Disorders at MU. “There are potential concerns that developmental exposure to BPA might increase an infant’s risk for autism spectrum disorder. Crying is the infant’s earliest communication form and changes in crying vocalization patterns might provide the earliest diagnostic tool for autism spectrum disorders (ASD). Thus, it is important to determine whether multigenerational exposure to BPA can alter pup vocalization patterns.”
The California mouse is used as a model for examining parental behaviors because they are monogamous and, much like humans, both male and female partners contribute to neonatal-rearing. Impaired care could lead to adverse consequences for the young and, since brain regions and hormones regulating biparental behaviors appear to be similar across species, this study likely has human implications.
Bisphenol A is a chemical that is used in a variety of consumer products, such as water bottles, dental composites and resins used to line metal food and beverage containers. These endocrine disruptors affect the global regulatory pathways of the brain often mimicking the function of natural hormones in animals and humans during crucial stages of development.
For the study, researchers exposed female and male California mice to one of three diets. One contained BPA; the second contained concentrations of ethinyl estradiol, another endocrine disruptor; and the third was free of endocrine disruptors. The offspring were placed on a endocrine disruptor-free diet when they were weaned and throughout their lifespan. Finally, the vocalization patterns of the third generation of mice, which also were not directly exposed to BPA or EE, were examined.
The grandoffspring were tested in “recording boxes” in isolation and away from their home-cages. There, the pups were recorded at intervals on given days that represented different times in their development. Vocalizations were measured for duration, as well as patterns or “syllables,” which represent phrases that pups emit when calling their parents for care. These vocalizations were then measured against pups that were not exposed to BPA or ethinyl estradiol (EE).
“We found that during specific postnatal periods, BPA and EE exposed, second-generation pups demonstrated augmented vocalization responses, which could indicate that they are in distress,” Rosenfeld said. “This could be problematic as their heightened vocalization patterns at certain postnatal days might also suggest they are perceiving and responding to the compromised parental care, as we have already shown, but yet, the parents are not adjusting the amount of parental care provided in response to their increased vocalizations. Such effects might also be attributed to multigenerational exposure to BPA and EE and suggest that even from early postnatal life grandoffspring whose grandparents were exposed to these endocrine disruptors are showing mental distress. While more work needs to be done, the multigenerational effects observed in California mice pups could thus also have ties to human communication deficits as seen in people with autism or other neurobehavioral disorders.”
Researchers who’ve analyzed ancient mitochondrial (mt)DNA isolated from a 22,000-year-old panda found in Cizhutuo Cave in the Guangxi Province of China — a place where no pandas live today — have revealed a new lineage of giant panda. shows that the ancient panda separated from present-day pandas 144,000 to 227,000 years ago, suggesting that it belonged to a distinct group not found.
The newly sequenced mitochondrial genome represents the oldest DNA evidence from pandas.
“Using a single complete mtDNA sequence, we find a distinct mitochondrial lineage, suggesting that the Cizhutuo panda, while genetically more closely related to present-day pandas than other bears, has a deep, separate history from the common ancestor of present-day pandas,” says Qiaomei Fu from the Chinese Academy of Sciences. “This really highlights that we need to sequence more DNA from ancient pandas to really capture how their genetic diversity has changed through time and how that relates to their current, much more restricted and fragmented habitat.”
Very little has been known about pandas’ past, especially in regions outside of their current range in Shaanxi province or Gansu and Sichuan provinces. Evidence suggests that pandas in the past were much more widespread, but it’s been unclear how those pandas were related to pandas of today.
In the new study, the researchers used sophisticated methods to fish mitochondrial DNA from the ancient cave specimen. That’s a particular challenge because the specimen comes from a subtropical environment, which makes preservation and recovery of DNA difficult.
The researchers successfully sequenced nearly 150,000 DNA fragments and aligned them to the giant panda mitochondrial genome reference sequence to recover the Cizhutuo panda’s complete mitochondrial genome. They then used the new genome along with mitochondrial genomes from 138 present-day bears and 32 ancient bears to construct a family tree.
Their analysis shows that the split between the Cizhutuo panda and the ancestor of present-day pandas goes back about 183,000 years. The Cizhutuo panda also possesses 18 mutations that would alter the structure of proteins across six mitochondrial genes. The researchers say those amino acid changes may be related to the ancient panda’s distinct habitat in Guangxi or perhaps climate differences during the Last Glacial Maximum.
The findings suggest that the ancient panda’s maternal lineage had a long and unique history that differed from the maternal lineages leading to present-day panda populations. The researchers say that their success in capturing the mitochondrial genome also suggests that they might successfully isolate and analyze DNA from the ancient specimen’s much more expansive nuclear genome.
“Comparing the Cizhutuo panda’s nuclear DNA to present-day genome-wide data would allow a more thorough analysis of the evolutionary history of the Cizhutuo specimen, as well as its shared history with present-day pandas.”
Tonsil and adenoid removal associated with long-term risks of respiratory, allergic and infectious diseases Removing tonsils and adenoids in childhood increases the long-term risk of respiratory, allergic and infectious diseases, according to researchers who have examined — for the first time — the long-term effects of the operations.
The researchers suggest renewed evaluation of alternatives to these common paediatric surgeries that include removal of tonsils (tonsillectomy) to treat chronic tonsillitis or adenoids (adenoidectomy) to treat recurrent middle ear infections.
The adenoids and tonsils are strategically positioned in the nose and throat respectively to act as a first line of defense, helping to recognise airborne pathogens like bacteria and viruses, and begin the immune response to clear them from the body.
The collaborative study initiated by the Copenhagen Evolutionary Medicine program looked at the long-term effects of removing the tonsils and adenoids in childhood, compared with children who had not undergone the surgeries.
University of Melbourne researcher Dr Sean Byars and Professor Jacobus Boomsma from the University of Copenhagen led the research, with Professor Stephen Stearns from Yale University.
The team analysed a dataset from Denmark of 1,189,061 children born between 1979 and 1999, covering at least the first 10 years and up to 30 years of their life. Of the almost 1.2 million children, 17,460 had adenoidectomies, 11,830 tonsillectomy and 31, 377 had adenotonsillectomies, where both tonsils and adenoids removed. The children were otherwise healthy.
“We calculated disease risks depending on whether adenoids, tonsils or both were removed in the first 9 years of life because this is when these tissues are most active in the developing immune system.”
The analysis showed:
- Tonsillectomy was associated with an almost tripled relative risk — the risk for those who had the operation compared with those who didn’t — for diseases of the upper respiratory tract. These included asthma, influenza, pneumonia and chronic obstructive pulmonary disorder or COPD, the umbrella term for diseases such as chronic bronchitis and emphysema.
- The absolute risk (which takes into account how common these diseases are in the community) was also substantially increased at 18.61 percent.
- Adenoidectomy was found to be linked with a more than doubled relative risk of COPD and a nearly doubled relative risk of upper respiratory tract diseases and conjunctivitis. The absolute risk was also almost doubled for upper respiratory diseases but corresponded to a small increase for COPD, as this is a rarer condition in the community generally.
“The association of tonsillectomy with respiratory disease later in life may therefore be considerable for those who have had the operation.”
The team delved deeper into the statistics to reveal how many operations needed to be performed for a disease to occur at a greater rate than normal, known as the number needed to treat or NNT.
“For tonsillectomy, we found that only five people needed to have the operation to cause an extra upper respiratory disease to appear in one of those people,” added Prof Boomsma.
The team also analysed conditions that these surgeries directly aimed to treat, and found mixed results:
- Adenoidectomy was associated with a significantly reduced risk for sleep disorders and all surgeries were associated with significantly reduced risk for tonsillitis and chronic tonsillitis, as these organs were now removed.
- However, there was no change in abnormal breathing up to the age of 30 for any surgery and no change in sinusitis after tonsillectomy or adenoidectomy.
- Following adenotonsillectomy the relative risk for those who had the operation was found to increase four or five-fold for otitis media (inflammation of the middle ear) and sinusitis also showed a significant increase.
The study suggests that shorter-term benefits of these surgeries may not continue up to the age of 30 apart from the reduced risk for tonsillitis (for all surgeries) and sleep disorders (for adenoidectomy).
Instead, the longer-term risks for abnormal breathing, sinusitis and otitis media were either significantly higher after surgery or not significantly different.
The researchers note that there will always be a need to remove tonsils and adenoids when those conditions are severe.
“But our observed results that show increased risks for long-term diseases after surgery support delaying tonsil and adenoid removal if possible, which could aid normal immune system development in childhood and reduce these possible later-life disease risks..
“As we uncover more about the function of immune tissues and the lifelong consequences of their removal, especially during sensitive ages when the body is developing, this will hopefully help guide treatment decisions for parents and doctors.”