When it comes to biological mechanisms of empathy, scientists are particularly interested in oxytocin, the so-called “love hormone.” High oxytocin levels predict sensitive parenting, but it isn’t clear how the oxytocin-related gene might generate variation in empathy and parental behavior. One possible explanation is epigenetic changes to the gene — a way of altering gene function without changing the actual DNA sequence. Specifically, “DNA methylation” — the addition of a chemical group called the “methyl” group at specific locations — in the oxytocin gene (called OXT) has been associated with personality traits and brain structure in humans. This raises a question: can methylation of OXT influence empathy in mothers? A team of scientists at University of Fukui in Japan, led by Prof. Akemi Tomoda, decided to find out, in a study published in Psychoneuroendocrinology.

Specifically, the scientists wanted to investigate how methylation of OXT, brain structure, and empathy are related in mothers. For this, they measured OXT methylation through analyses of saliva samples from 57 Japanese mothers who were caring for at least one young child. Moreover, they used an MRI technique called “voxel-based morphometry” to examine the size of brain regions related to OXT methylation, aiming to identify any connections between brain morphology and DNA methylation. This is part of an exciting new field called “imaging epigenetics” that seeks to explain behavior through linking epigenetic changes with brain structures and/or functions. Finally, they used a well-established psychology questionnaire to determine the levels of cognitive and affective empathy they have.

The findings showed that OXT methylation was positively correlated with a mother’s “personal distress,” relating to harsh parenting. Additionally, OXT methylation was negatively correlated with the volume of gray matter in the right inferior temporal gyrus. In other words, high methylation of the oxytocin gene lowered brain volume in the inferior temporal gyrus while increasing personal distress. “This is the first study to find a correlation between DNA methylation of the oxytocin gene with empathy, and the first to link that methylation with both empathy and variation in brain structure,” Prof. Tomoda commented. “So, we’ve gained very important insight into the relationship between this gene and the phenotype — or the physical manifestation of gene expression.”

The researchers also used statistical analyses to find out whether DNA methylation affected changes to brain structure, or vice versa. But they did not find a significant effect of gray matter volume of the inferior temporal gyrus on OXT methylation and empathy. This means that brain structure did not appear to mediate the relationship between epigenetic changes to the OXT gene and empathy.

These findings shed light on the complex processes involved in maternal empathy, which could have a real contribution in understanding psychological development in children. As Prof. Tomoda explains, “Our study really helps to clarify the link between oxytocin gene methylation and parental empathy, as well as the effects on empathy-related parts of the brain. This understanding augments efforts to better understand maltreated children and contributes to their healthy development.”

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However, producing electricity from methanol at room temperature requires a direct methanol fuel cell (DMFC); a device that, so far, offers subpar performance. One of the main problems in DMFCs is the undesired “methanol oxidation” reaction, which occurs during methanol crossover,” that is, when it passes from the anode to the cathode. This reaction results in the degradation of the platinum (Pt) catalyst that is essential for the cell’s operation. Although certain strategies to mitigate this problem have been proposed, so far none has been good enough owing to cost or stability issues.

Fortunately, in a recent study published in ACS Applied Materials & Interfaces, a team of scientists from Korea has come up with a creative and effective solution. They fabricated — through a relatively simple procedure — a catalyst made of Pt nanoparticles encapsulated within a carbon shell. This shell forms an almost impenetrable carbon network with small openings caused by nitrogen defects. While oxygen, one of the main reactants in DMFCs, can reach the Pt catalyst through these “holes,” methanol molecules are too big to pass through. “The carbon shell acts as a molecular sieve and provides selectivity toward the desired reactants, which can actually reach the catalyst sites. This prevents the undesirable reaction of the Pt cores,” explains Professor Oh Joong Kwon from Incheon National University, Korea, who led the study.

The scientists conducted various types of experiments to characterize the overall structure and composition of the prepared catalyst and proved that oxygen could make it through the carbon shell and methanol could not. They also found a straightforward way to tune the number of defects in the shell by simply changing the temperature during a heat treatment step. In subsequent experimental comparisons, their novel shelled catalyst outperformed commercial Pt catalysts and also offered much higher stability.

Prof Kwon has been working on improving fuel cell catalysts for the past 10 years, motivated by the many ways in which this technology could find its way into our daily lives. “DMFCs have a higher energy density than lithium-ion batteries and could therefore become alternative power sources for portable devices, such as laptops and smartphones,” he remarks.

With the future of our planet on the line, switching to alternative fuels should be one of humanity’s top goals, and this study is a remarkable step in the right direction.

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The study, by a team of Brown University researchers, used computer models to simulate the airflow inside a compact car with various combinations of windows open or closed. The simulations showed that opening windows — the more windows the better — created airflow patterns that dramatically reduced the concentration of airborne particles exchanged between a driver and a single passenger. Blasting the car’s ventilation system didn’t circulate air nearly as well as a few open windows, the researchers found.

“Driving around with the windows up and the air conditioning or heat on is definitely the worst scenario, according to our computer simulations,” said Asimanshu Das, a graduate student in Brown’s School of Engineering and co-lead author of the research. “The best scenario we found was having all four windows open, but even having one or two open was far better than having them all closed.”

Das co-led the research with Varghese Mathai, a former postdoctoral researcher at Brown who is now an assistant professor of physics at the University of Massachusetts, Amherst. The study is published in the journal Science Advances.

The researchers stress that there’s no way to eliminate risk completely — and, of course, current guidance from the U.S. Centers for Disease Control (CDC) notes that postponing travel and staying home is the best way to protect personal and community health. The goal of the study was simply to study how changes in airflow inside a car may worsen or reduce risk of pathogen transmission.

The computer models used in the study simulated a car, loosely based on a Toyota Prius, with two people inside — a driver and a passenger sitting in the back seat on the opposite side from the driver. The researchers chose that seating arrangement because it maximizes the physical distance between the two people (though still less than the 6 feet recommended by the CDC). The models simulated airflow around and inside a car moving at 50 miles per hour, as well as the movement and concentration of aerosols coming from both driver and passenger. Aerosols are tiny particles that can linger in the air for extended periods of time. They are thought to be one way in which the SARS-CoV-2 virus is transmitted, particularly in enclosed spaces.

Part of the reason that opening windows is better in terms of aerosol transmission is because it increases the number of air changes per hour (ACH) inside the car, which helps to reduce the overall concentration of aerosols. But ACH was only part of the story, the researchers say. The study showed that different combinations of open windows created different air currents inside the car that could either increase or decrease exposure to remaining aerosols.

Because of the way air flows across the outside of the car, air pressure near the rear windows tends to be higher than pressure at the front windows. As a result, air tends to enter the car through the back windows and exit through the front windows. With all the windows open, this tendency creates two more-or-less independent flows on either side of the cabin. Since the occupants in the simulations were sitting on opposite sides of the cabin, very few particles end up being transferred between the two. The driver in this scenario is at slightly higher risk than the passenger because the average airflow in the car goes from back to front, but both occupants experience a dramatically lower transfer of particles compared to any other scenario.

The simulations for scenarios in which some but not all windows are down yielded some possibly counterintuitive results. For example, one might expect that opening windows directly beside each occupant might be the simplest way to reduce exposure. The simulations found that while this configuration is better than no windows down at all, it carries a higher exposure risk compared to putting down the window opposite each occupant.

“When the windows opposite the occupants are open, you get a flow that enters the car behind the driver, sweeps across the cabin behind the passenger and then goes out the passenger-side front window,” said Kenny Breuer, a professor of engineering at Brown and a senior author of the research. “That pattern helps to reduce cross-contamination between the driver and passenger.”

It’s important to note, the researchers say, that airflow adjustments are no substitute for mask-wearing by both occupants when inside a car. And the findings are limited to potential exposure to lingering aerosols that may contain pathogens. The study did not model larger respiratory droplets or the risk of actually becoming infected by the virus.

Still, the researchers say the study provides valuable new insights into air circulation patterns inside a car’s passenger compartment — something that had received little attention before now.

“This is the first study we’re aware of that really looked at the microclimate inside a car,” Breuer said. “There had been some studies that looked at how much external pollution gets into a car, or how long cigarette smoke lingers in a car. But this is the first time anyone has looked at airflow patterns in detail.”

The research grew out of a COVID-19 research task force established at Brown to gather expertise from across the University to address widely varying aspects of the pandemic. Jeffrey Bailey, an associate professor of pathology and laboratory medicine and a coauthor of the airflow study, leads the group. Bailey was impressed with how quickly the research came together, with Mathai suggesting the use of computer simulations that could be done while laboratory research at Brown was paused for the pandemic.

“This is really a great example of how different disciplines can come together quickly and produce valuable findings,” Bailey said. “I talked to Kenny briefly about this idea, and within three or four days his team was already doing some preliminary testing. That’s one of the great things about being at a place like Brown, where people are eager to collaborate and work across disciplines.”