Category: Science

Researchers have developed a stretchable strain sensor that has an unprecedented combination of sensitivity and range.

That allows it to detect even minor changes in strain with greater range of motion than previous technologies.

The researchers demonstrated the sensor’s utility by creating new health monitoring and human-machine interface devices.

Strain is a measurement of how much a material deforms from its original length. For example, if you stretched a rubber band to twice its original length, its strain would be 100%.

“And measuring strain is useful in many applications, such as devices that measure blood pressure and technologies that track physical movement,” says Yong Zhu, corresponding author of a paper on the work and professor of mechanical and aerospace engineering at North Carolina State University.

“But to date there’s been a trade-off. Strain sensors that are sensitive—capable of detecting small deformations—cannot be stretched very far. On the other hand, sensors that can be stretched to greater lengths are typically not very sensitive. The new sensor we’ve developed is both sensitive and capable of withstanding significant deformation,” says Zhu.

“An additional feature is that the sensor is highly robust even when over-strained, meaning it is unlikely to break when the applied strain accidentally exceeds the sensing range.”

The new sensor consists of a silver nanowire network embedded in an elastic polymer. The polymer features a pattern of parallel cuts of a uniform depth, alternating from either side of the material: one cut from the left, followed by one from the right, followed by one from the left, and so on.

“This feature—the patterned cuts—is what enables a greater range of deformation without sacrificing sensitivity,” says Shuang Wu, who is first author of the paper and a recent PhD graduate.

The sensor measures strain by measuring changes in electrical resistance. As the material stretches, resistance increases. The cuts in the surface of the sensor are perpendicular to the direction that it is stretched. This does two things. First, the cuts allow the sensor to deform significantly. Because the cuts in the surface pull open, creating a zigzag pattern, the material can withstand substantial deformation without reaching the breaking point. Second, when the cuts pull open, this forces the electrical signal to travel further, traveling up and down the zigzag.

“To demonstrate the sensitivity of the new sensors, we used them to create new wearable blood pressure devices,” Zhu says. “And to demonstrate how far the sensors can be deformed, we created a wearable device for monitoring motion in a person’s back, which has utility for physical therapy.”

“We have also demonstrated a human-machine interface,” Wu says. “Specifically, we used the sensor to create a three-dimensional touch controller that can be used to control a video game.”

“The sensor can be easily incorporated into existing wearable materials such as fabrics and athletic tapes, convenient for practical applications,” Zhu says. “And all of this is just scratching the surface. We think there will be a range of additional applications as we continue working with this technology.”

The paper appears in the journal ACS Applied Materials & Interfaces.

Support for the work came from the National Science Foundation, the National Institutes of Health, and the US Department of Defense.

Source: NC State

A new study with mice finds that proteins made by stem cells that regenerate the cornea may be new targets for treating and preventing injuries.

People with a condition known as dry eye disease are more likely than those with healthy eyes to suffer injuries to their corneas.

Dry eye disease occurs when the eye can’t provide adequate lubrication with natural tears. People with the common disorder use various types of drops to replace missing natural tears and keep the eyes lubricated, but when eyes are dry, the cornea is more susceptible to injury.

“We have drugs, but they only work well in about 10% to 15% of patients,” says senior investigator Rajendra S. Apte, professor in the department of ophthalmology and visual sciences at Washington University in St. Louis.

“In this study involving genes that are key to eye health, we identified potential targets for treatment that appear different in dry eyes than in healthy eyes.

“Tens of millions of people around the world—with an estimated 15 million in the United States alone—endure eye pain and blurred vision as a result of complications and injury associated with dry eye disease, and by targeting these proteins, we may be able to more successfully treat or even prevent those injuries.”

For the study in the Proceedings of the National Academy of Sciences, the researchers analyzed genes expressed by the cornea in several mouse models—not only of dry eye disease, but also of diabetes and other conditions. They found that in mice with dry eye disease, the cornea activated expression of the gene SPARC. They also found that higher levels of SPARC protein were associated with better healing.

“We conducted single-cell RNA sequencing to identify genes important to maintaining the health of the cornea, and we believe that a few of them, particularly SPARC, may provide potential therapeutic targets for treating dry eye disease and corneal injury,” says first author Joseph B. Lin, an MD/PhD student in Apte’s lab.

“These stem cells are important and resilient and a key reason corneal transplantation works so well,” Apte explains. “If the proteins we’ve identified don’t pan out as therapies to activate these cells in people with dry eye syndrome, we may even be able to transplant engineered limbal stem cells to prevent corneal injury in patients with dry eyes.”

The National Eye Institute, the National Institute of Diabetes and Digestive and Kidney Diseases, and the National Institute of General Medical Sciences of the National Institutes of Health supported the work. Additional funding came from the Jeffrey T. Fort Innovation Fund, a Centene Corp. contract for the Washington University-Centene ARCH Personalized Medicine Initiative, and Research to Prevent Blindness.

Source: Washington University in St. Louis

New research reveals an added layer of nuance in our sense of smell.

The delicate fragrance of jasmine is a delight to the senses. The sweet scent is popular in teas, perfumes and potpourri. But take a whiff of the concentrated essential oil, and the pleasant aroma becomes almost cloying.

Part of the flower’s smell actually comes from the compound skatole, a prominent component of fecal odor.

“Consider for instance the smell of a ripe banana from a distance (sweet and fruity) versus up-close (overpowering and artificial).”

Our sense of smell is clearly a complex process; it involves hundreds of different odorant receptors working in concert. The more an odor stimulates a particular neuron, the more electrical signals that neuron sends to the brain.

But the new research reveals that these neurons actually fall silent when an odor rises above a certain threshold. Remarkably, this was integral to how the brain recognized each smell.

“It’s a feature; it’s not a bug,” says Matthieu Louis, an associate professor in the department of molecular, cellular, and developmental biology at the University of California, Santa Barbara.

The paradoxical finding, published in Science Advances, shakes up our understanding of olfaction.

“The same odor can be represented by very different patterns of active olfactory sensory neurons at different concentrations,” Louis says. “This might explain why some odors can be perceived as very different to us at low, medium, and very high concentrations. Consider for instance the smell of a ripe banana from a distance (sweet and fruity) versus up-close (overpowering and artificial).”

Humans have several million sensory neurons in our noses, and each of these has one type of odorant receptor. Altogether, we have about 400 different types of receptors with overlapping sensitivity. Each chemical compound is like a different shoe that the receptor is trying on. Some shoes fit snugly, some fit well, while others don’t fit at all. A better fit produces a stronger response from the receptor. Increasing an odor’s concentration recruits neurons with receptors that have are less sensitive to that substance. Our brain uses the combination of activated neurons to distinguish between odors.

Scientists thought that neurons would effectively max out above certain odor concentrations, at which point their activity would plateau. But the team led by Louis’ graduate student, David Tadres, found the exact opposite: Neurons actually fall silent above a certain level, with the most sensitive ones dropping off first.

Looking at flies

Fruit fly larvae make an ideal model for studying olfaction. They have as many types of odorant receptors as the number of sensory neurons—namely, 21. This one-to-one correspondence makes it simple to test what each neuron is doing.

For the study, Tadres examined larvae with a mutation that entirely eliminated their sense of smell. He then selectively turned that sense back on in a single sensory neuron, enabling the larvae to detect only odors that activated that specific receptor. He placed them next to an odor source and watched.

Even with a single functioning olfactory channel, the larvae could still move toward the stronger smell. But remarkably, they stopped a certain distance away from the source, and just circled it in a fixed orbit. Tadres repeated the experiment with a neuron slightly less sensitive to the odor he was testing, and found that the larvae got closer to the source before stopping.

Puzzled by this behavior, Tadres used electrodes to measure the activity of the sensory neuron. As expected, signaling increased as the odor became more concentrated. But rather than plateau above a certain level, the activity crashed to zero. That’s why the mutant larvae circled the odor source; above a certain concentration, the smell simply disappeared.

“The silencing of the olfactory sensory neuron could easily explain the circling behavior, which was mysterious before,” Tadres says. “From there it wasn’t hard to extrapolate that the current view of how odors are encoded at different concentrations needed to be updated.”

Researchers knew that excessive stimulation can cause nerves to go silent, an effect called “depolarization block.” However, the consensus was that this sort of overload doesn’t occur under natural, healthy conditions. Indeed, this response is associated with issues like epilepsy when it occurs in the central brain. But when Tadres observed it affecting the larvae’s behavior, he suspected that it wasn’t merely an artifact of the experiment.

Digging deeper

Tadres and Louis began investigating the cause of the depolarization block. For assistance, they reached out to Professor Jeff Moehlis, chair of the mechanical engineering department, and Louis’ doctoral student Philip Wong (co-advised by Moehlis), who started constructing a mathematical model of the system.

The voltage across a neuron’s membrane can be described by a system of equations. This model was a breakthrough finding in 1952, and earned a Nobel Prize for its discoverers, Alan Hodgkin and Andrew Huxley. For this case study, Wong added a mathematical representation of the odorant receptor, the “trigger” that initiates the rest of the model. He also included a modification from the field of epilepsy research wherein high stimulation turns off certain ion channels in the cell membrane, preventing a neuron from firing.

Wong’s model was able to fit and predict Tadres’ measurements of the neuron’s electrical activity. “This was quite useful because the electrophysiology data was difficult to collect and very time consuming to analyze,” Wong says.

In addition to corroborating the experimental results, the model is guiding the team as they continue investigating this effect. “This model may tell us exactly how each neuron is responding to different odors,” Wong says.

The model’s success points to a possible source of the depolarization block: a specific ion channel present in neurons across the animal kingdom. If true, this suggests that most sensory neurons might fall silent following strong and sustained stimulation. The team hopes to validate this hypothesis in an upcoming study.

What’s more, the model predicted that the system would behave differently going up from low odor concentrations versus coming down from high concentrations. Measuring the voltage of the larvae’s neurons confirmed this. When going down, the neuron did not reactivate below the threshold where it had fallen silent. In fact, it largely remained silent until the odor concentration came back down to zero before returning to normal activity.

Our complex sense of smell

This study demonstrated that high odor concentrations can silence the most sensitive receptors. This counterintuitive result marks a fundamental shift in our understanding of smell.

“As you increase the concentration of an odor, you’ll start recruiting more and more odorant receptors that aren’t as sensitive to that compound,” Louis explains. “And so, the common view until our work was that you just kept adding active odorant receptors to the picture.”

This makes sense, until you consider the system as a whole. If this were the case, then a compound should activate pretty much all of the receptors above a certain level. “So it would be impossible for you to distinguish between two different odors at very high concentrations,” Tadres says. “And that’s clearly not the case.”

Having certain sensory neurons drop out as others join in might help preserve the distinction between odors at high concentrations. And this could prove important for survival. It might prevent poisons and nutrients that share certain compounds from smelling alike when you take a big whiff of them.

It could also have consequences for how we perceive odors. “We speculate that removing successive high-sensitivity olfactory sensory neurons is like removing the root of a musical chord,” Louis says. “This omission of the root is going to alter the way your brain perceives the chord associated with a set of notes. It’s going to give it a different meaning.”

A subtle floral note suggests an orchard may be in bloom nearby, useful information for a hungry animal. Meanwhile, the same compounds in higher concentrations could produce the pungent ripeness of decaying fruit or even sewage: something best avoided. Studies like this reveal ever more complexities to our sense of smell, which evolved to help us navigate an equally complex chemical landscape.

Source: UC Santa Barbara

A study on the factors driving a rise in weight gain among pregnant woman in Nepal rules out poor diet quality in the first trimester as one of the major causes, say the researchers.

Historically, one of the greatest challenges facing pregnant women in Nepal and other low-income countries was undernourishment, a result of poverty. While that continues to be a concern, doctors are seeing some of the same issues confronting women in western nations: excessive weight gain and the health risks that come with it, such as high blood pressure and gestational diabetes.

Obstacles to addressing the problem included a lack of data, prompting a pilot study on gestational weight gain among pregnant women in Nepal by Shristi Rawal, an assistant professor of nutritional sciences at the Rutgers School of Health Professions; Kelly Martin, a 2021 graduate of the doctor in clinical nutrition program and an assistant professor at the State University of New York College at Oneonta; and other faculty members.

Their findings appear in the journal BMC Nutrition.

Rawal, who is from Nepal, says the impact of diet quality has been studied in wealthier countries, but had not been investigated in the context of many low-income countries, including Nepal.

“Studies on perinatal complications have largely been based on Caucasian samples from high income countries, and there has been a lack of diversity in general in terms of women represented in these studies,” she says. “Pregnancy complications are increasing in Nepal, and no one was doing this work there. This is a first step.”

The study tracked 101 pregnant women receiving prenatal care at Dhulikhel Hospital at Kathmandu University. Rawal and her colleagues administered a 21-item questionnaire to assess intake of foods from groups categorized either as healthy (such as whole grains, fruits, and vegetables) or unhealthy (such as desserts, refined grains, and red meats), to the participants.

The study looked at diet quality in the first trimester and the rate of gestational weight gain from second to the third trimester but found no link between diet quality in early pregnancy and rate of gestational weight gain. It did find that a high intake of red meat could be a potential factor in driving up weight.

“The most striking result is that so many had excessive rate of gestational weight gain,” says Rawal. “If diet quality is not it, it could be daily caloric intake, physical activity, or sleep that could be associated with gestational weight gain. It could be other diet, lifestyle, or clinical factors. The next step is collecting more data and in a larger sample. ”

The pilot study established the need to conduct a larger birth cohort study with hundreds to thousands of women seeking antenatal care at Dhulikhel Hospital.

A key part of the pilot study also was to evaluate the efficacy of a novel dietary screening tool in capturing valid dietary data in the target population of Nepalese pregnant women.

In a paper published in the Maternal and Child Health Journal, the researchers conclude that the 21-question dietary screen tool modified for use by pregnant Nepalese woman is a valid and reliable instrument for assessing the dietary intake of pregnant women in Nepal.

“This adds credence to the tool, and we now know that it has cultural applicability to the setting and that it measures what it is intended to measure,” says Martin, who was the first author of both papers. “This is important for conducting further studies on diet quality in this population.”

Rawal is in the midst of a study testing a mobile app that supports Nepalese women with gestational diabetes by providing them with information and tools to adopt diet and lifestyle modifications needed to self-manage their condition.

Source: Rutgers University

HELSINKI — China is aiming to expand the use of its coastal Wenchang spaceport to both allow a greater overall launch rate and establish new facilities needed for crewed lunar missions.

The Wenchang Satellite Launch Center was completed in 2014 and has since allowed China to launch its new generation kerolox and cryogenic rockets. These have in turn enabled the country to launch interplanetary and lunar missions and construct and supply its Tiangong space station.

Now though the spaceport is being expanded to additionally facilitate commercial launches and the growth of China’s commercial space sector and, eventually, launch a new-generational crew launch vehicle and the super heavy-lift Long March 9 rocket. 

The development is an apparent part of long term plans for China to upgrade its overall space capabilities.

“In the near future, Wenchang will see its launch frequency go from between six to eight times a year, to 20 or 30 times a year,” Zhong Wen’an, chief engineer of the Xichang Satellite Launch Center which oversees Wenchang Satellite Launch Center, told CCTV Dec. 31.

“This is not only a change in quantity but also one in quality. We are also going to add more sites for [the launch of] human moon-landing missions, heavy rockets and commercial ones.” Zhong said.

The crew launcher is expected to have a test launch around 2026, and a pair of the rockets could support a short-term human lunar landing mission before 2030. 

The Long March 9 is planned for use in construction of China’s ILRS lunar base plan and other space infrastructure projects, including space-based solar power plans.

More immediately however, progress on the commercial launch site can be seen from both aerial and satellite imagery. Wenchang has already attracted a number of launch and other space-related companies to establish facilities in the area.

Construction of the Hainan commercial launch centre continues apace. https://t.co/o6Ml8rSBbs

— Andrew Jones (@AJ_FI) December 29, 2022

China has three inland spaceports at Jiuquan in the northwest, Xichang in the southwest and Taiyuan in north China. Jiuquan has recently been expanded to facilitate both launches of commercial solid rockets and new methane-liquid oxygen rockets. 

The country has also begun launching from mobile platforms from the Yellow Sea, supported by infrastructure developed near Haiyang, Shandong province.

Wenchang however has a number of advantages, including the lowest latitude of any of China’s spaceports. It is also accessible by sea, allowing large diameter rocket components to be delivered there. 

China’s inland launch sites are limited in the size of rocket they can launch due to a reliance on the national railway system and its capacities. They also create debris issues downrange due to falling spent rocket stages.

China’s largest rockets, the Long March 5 and 5B, launch from Wenchang. These launch vehicles have allowed China to launch its first interplanetary mission, Tianwen-1, a first lunar sample return mission, and launch the roughly 22-ton modules that make up the Tiangong space station.

SAN FRANCISCO – A bootcamp aimed at helping startups navigate the space sector’s complex regulatory landscape is coming to New Mexico.

The Space Regulatory Bootcamp, backed by the U.S. Air Force Research Laboratory and SpaceWERX, is scheduled for Feb. 21-23 at Q Station, a collaboration center for New Mexico’s space industry in Albuquerque.

“Many companies need a lot of help understanding what is required if you’re going to do business with the federal government,” Gabe Mounce, director of AFRL’s Outreach and Tech Engagement Office, and SpaceWERX deputy director, told SpaceNews. “For instance, export laws are very important if you’re going to try to get a government contract, even a Small Business Innovation Research or Small Business Technology Transfer contract.”

In addition to export control, topics to be covered in the Space Regulatory Bootcamp, being organized by Washington-based Aegis Trade Law, include cybersecurity, foreign investment, crowdfunding, government licensing and federal contracting regulations.

“A lot of the work that we’ve done as a law firm has been educating our clients,” said Jack Shelton, Aegis co-founder and partner. “That’s what spawned the desire to put together a curriculum and start getting people educated on this stuff.”

Shelton, along with a group of space attorneys in partnership with AFRL, also are establishing the Association of Commercial Space Professionals, a public benefit company to offer affordable regulatory and legal resources for space startups.

Recent declines in launch costs and technological innovations like miniature electronic components and additive manufacturing have lowered the barriers to entry for space-related startups. Government agencies, eager to take advantage of commercial space innovation, have established incubators, accelerators and financing programs to help the startups succeed.

“It now feels like every entrepreneur who has ever tried to do something in any other sector is pivoting that product or service to space in some capacity, which is amazing,” Mounce said. “But that also means a lot of companies and founders don’t understand how they might be crossways with the U.S. if they are not careful in how they progress through their company establishment.”

One of the Space Regulatory Bootcamp sessions, for example, will focus on the important differences between pitching a business plan to the government versus pitching to investors, Shelton said.

While the first Space Regulatory Bootcamp was conceived as a pilot program, “I suspect because of the demand we are going to keep doing this,” Mounce said. “In fact, I’ve already been pushing the team figure out how we evolve the model after this pilot.”

Participants in the first Space Regulatory Bootcamp will pay $900 for the three-day meeting.

“We want to make sure it’s affordable,” Shelton said, “but also to make sure that we’re able to cover our costs.”

Correction: The Association of Commercial Space Professionals is a public benefit company, not a nonprofit. 

WASHINGTON — Despite a small funding increase for 2023, NASA’s planetary science programs still face “significant stress” financially that contributed to the delay of one mission and could push back the start of others.

NASA received $3.2 billion for planetary science in the fiscal year 2023 omnibus spending bill signed into law Dec. 29. That was about $80 million more than what the agency received for planetary science in 2022 and $40 million above its request for 2023.

That increase, though, may do little to address some of the challenges NASA has been facing with current and future missions. Lori Glaze, director of NASA’s planetary science division, outlined those issues in presentations last month to the agency’s Planetary Science Advisory Committee and at a town hall during the Fall Meeting of the American Geophysical Union (AGU).

Among those challenges are ongoing impacts from the pandemic. “There have been some substantial costs in order to accommodate the impacts from COVID,” she said at the AGU meeting. Those costs, she said, had to be absorbed from within the planetary science budget.

There have also been supply chain issues for missions in development, along with inflation and higher labor rates. In addition to higher costs, she said that supply chain issues have required missions to order long-lead items earlier than expected, which requires more money earlier in the project’s development than anticipated.

Glaze said that, as those missions prepare for launch, they have been asking for more money for operations than anticipated. “I don’t think we’re very good at estimating what operational costs will be,” she said at the advisory committee meeting. Operations costs, she noted, are not part of the cost cap for competed planetary science missions, and thus don’t get refined until later in the mission.

“There’s significant stress on the planetary budget,” she said at the AGU town hall. “It’s been a bit brittle and fragile.”

Those issues came to a head in mid-2022 when Psyche, a Discovery-class mission to the asteroid of the same name, suffered delays in testing flight software that caused it to miss its launch window. NASA initiated an independent review that concluded that while Psyche is back on track for a launch now scheduled for October 2023, there were broader institutional issues at the Jet Propulsion Laboratory, which is developing Psyche, that had to be corrected.

As part of NASA’s response to that review, the agency said Nov. 4 it would delay by at least three years the launch of a Venus orbiter mission called VERITAS that is also part of the Discovery program and under development at JPL. Glaze suggested that the budgetary pressures facing the planetary science program left her with no other options to address the Psyche problems than to delay VERITAS.

“This was not a decision that was easily arrived at,” she said at the AGU town hall. “I do not think this is a good answer. I think it is the least of the bad answers that we could come up with.”

Those budgetary stresses could also affect implementation of the planetary science decadal survey released in April 2022. Glaze reiterated concerns she made in August that funding projections for planetary science fell short of the “level” budget in the decadal, the lower of two budget profiles included in that report. While the level budget projected spending to increase to more than $3.5 billion a year by the middle of the decade, the fiscal year 2023 budget proposal kept spending for planetary science at less than $3.2 billion through 2026, increasing to $3.3 billion in 2027.

“We will continue to try and secure the funding so that we can execute what is in the decadal survey,” she said at the town hall. “The key takeaway from this is that there may be a slight delay in getting some of the activities kicked off.”

As in August, she said those delays would likely affect the top-priority large, or flagship, mission from the decadal, a Uranus orbiter and probe. The science for such a mission is already well-established, she said, so the focus in the near term will be technical studies, including options to launch the mission after 2031, when a Jupiter gravity assist that would shorten the travel time to Uranus is no longer available.

A dramatic shift toward remote work during the COVID-19 pandemic caused telecommuting parents in the United States to spend significantly more time “parenting” their children in the first year of the pandemic than they did before, according to a new study.

In the study in the Journal of Marriage and Family, the researchers found that parents working remotely, particularly mothers, significantly increased the amount of time they spent on supervisory parenting—or “watching” their children as they did other activities, such as their job-related duties, not focused on childcare.

Mothers, both those working remotely and on-site, also altered their schedules more often during the pandemic to extend the paid workday.

However, the findings show no overall increase in the amount of time working parents spent on primary childcare duties—feeding, bathing, and other basic care—during the pandemic, regardless of whether they commuted to their jobs or worked remotely.

“The lack of increase in time devoted to basic childcare activities is much less surprising given the spike in telecommuting parents working while in their children’s presence or supervising them,” says coauthor Emma Zang, an assistant professor of sociology, biostatistics, and global affairs at Yale University.

“Our study demonstrates that parenting during the pandemic’s first year, particularly for moms working from home, often required multi-tasking and adjusting work schedules. This suggests that while remote work provides parents greater flexibility, there are potential negative effects on work quality and stress that are disproportionately faced by mothers.”

The study is the first to utilize time-diary data in the United States—records of individuals’ daily activity—to examine the association between parents’ work arrangements during the pandemic and how they use their time. Specifically, Zang and her coauthors—Thomas Lyttelton of Copenhagen Business School and Kelly Musick of Cornell University—analyzed nationally representative data from the 2017–2020 American Time Use Survey to estimate changes in paid work, childcare, and housework among parents working remotely and on site from before the pandemic and after its onset.

Time parents spent with their children present, but not directly supervising them, increased by more than an hour per day among telecommuting mothers and fathers during the pandemic, and supervisory parenting increased over the same period by 4.5 hours among mothers and 2.5 among fathers, on average, over the same period. (A 104% increase over pre-pandemic levels for moms, and an 87% increase for dads.) The much steeper increase in the amount of time spent by mothers on supervisory duties suggests they have disproportionate responsibility for childcare relative to fathers, the researchers say.

The study also revealed that most of the time telecommuting parents spent in their children’s presence or supervising them on workdays during the pandemic in 2020 occurred while they were simultaneously engaged in job-related activities. Moms and dads spent just under an additional hour of work time with children present; mothers spent four additional hours of work time supervising children, compared to two more among fathers.

Parents who commuted to work did not see a statistically significant increase in these areas, suggesting that they were constrained in how they could respond to rising childcare demands during the pandemic, the researchers note.

“Remote work allowed parents to triage during the disruptions of daycare closures and online schooling, even if the burden fell disproportionately on mothers,” says Lyttelton. “Commuting parents had even less leeway in their schedules.”

There is evidence of a reduction in the gender gap concerning household labor between telecommuting mothers and fathers during the pandemic. The study found that parents, particularly fathers, working from home increased the amount of time they spent on household chores, such as laundry and cleaning, during the pandemic. Fathers spent an additional 30 minutes per day on housework—up from 44 minutes per day pre-pandemic—while mothers logged an extra 16 minutes of chores.

The researchers also found a disparity between telecommuting mothers and fathers in the amount of time they spent playing with their children, as opposed to time spent with children that didn’t involve play. Moms working from home spent an additional 16 minutes per day playing with their kids while dads across both work arrangements played with their children an extra six minutes per day. Mothers working on-site saw no increase during the pandemic, according to the study.

The findings on housework and time spent playing with children differ from evidence collected prior to the pandemic, which had showed that remote work is associated with large gender disparities in housework and smaller disparities in childcare, the researchers note.

Mothers working remotely and on-site both reported altering their schedules during the pandemic, working during non-standard hours presumably to meet the increased demands of parenting, the researchers say.

“Our work provides insights into important dimensions of inequality during the pandemic between mothers and fathers and parents who work from home and on-site workers,” Zang says. “The pandemic underscored that our work culture is unaccommodating toward the demands parents face and a policy infrastructure ill-suited to support working parents.

“We need change at the public and private levels to better serve the wellbeing of working families.”

Source: Yale University

Researchers have shown how nitrogen fertilizer could be produced more sustainably.

This is necessary not only to protect the climate, but also to reduce dependence on imported natural gas and to increase food security.

Intensive agriculture is possible only if the soil is fertilized with nitrogen, phosphorus, and potassium. While phosphorus and potassium can be mined as salts, nitrogen fertilizer has to be produced laboriously from nitrogen in the air and from hydrogen. And, the production of hydrogen is extremely energy-intensive, currently requiring large quantities of natural gas or—as in China—coal.

Besides having a correspondingly large carbon footprint, nitrogen fertilizer production is vulnerable to price shocks on the fossil fuels markets.

Paolo Gabrielli, senior scientist at the Laboratory of Reliability and Risk Engineering at ETH Zurich, has collaborated with Lorenzo Rosa, principal investigator at Carnegie Institution for Science at Stanford University, to investigate various carbon-neutral production methods for nitrogen fertilizer.

In their study, the two researchers conclude that a transition in nitrogen production is possible and that such a transition may also increase food security. However, alternative production methods have advantages and disadvantages. Specifically, the two researchers examined three alternatives:

• Producing the necessary hydrogen using fossil fuels as in the business-as-usual, only instead of emitting the greenhouse gas CO2 into the atmosphere, it is captured in the production plants and permanently stored underground (carbon capture and storage, CSS). This requires not only an infrastructure for capturing, transporting, and storing the CO2 but also correspondingly more energy. Despite this, it is a comparatively efficient production method. However, it does nothing to reduce dependence on fossil fuels.
• Electrifying fertilizer production by using water electrolysis to produce the hydrogen. This requires averagely 25 times as much energy as today’s production method using natural gas, so it would take huge amounts of electricity from carbon-neutral sources. For countries with an abundance of solar or wind energy, this might be an appealing approach. However, given plans to electrify other sectors of the economy in the name of climate action, it might lead to competition for sustainable electricity.
• Synthesizing the hydrogen for fertilizer production from biomass. Since it requires a lot of arable land and water, ironically this production method competes with food production. But the study’s authors point out that it makes sense if the feedstock is waste biomass—for example, crop residues.

The researchers say that the key to success is likely to be a combination of all these approaches depending on the country and on specific local conditions and available resources.

In any case, it is imperative that agriculture make a more efficient use of nitrogen fertilizers, as Rosa stresses: “Addressing problems like over-fertilization and food waste is also a way to reduce the need for fertilizer.”

In the study, the researchers also sought to identify the countries of the world in which food security is currently particularly at risk owing to their dependence on imports of nitrogen or natural gas. The following countries are particularly vulnerable to price shocks in the natural gas and nitrogen markets: India, Brazil, China, France, Turkey, and Germany.

Decarbonizing fertilizer production would in many cases reduce this vulnerability and increase food security. At the very least, electrification via renewables or the use of biomass would reduce the dependence on natural gas imports. However, the researchers put this point into perspective: all carbon-neutral methods of producing nitrogen fertilizer are more energy intensive than the current method of using fossil fuels. In other words, they are still vulnerable to certain price shocks—not on natural gas markets directly, but perhaps on electricity markets.

Decarbonization is likely to change the line-up of countries that produce nitrogen fertilizer, the scientists point out in their study. As things stand, the largest nitrogen exporting nations are Russia, China, Egypt, Qatar, and Saudi Arabia. Except for China, which has to import natural gas, all these countries can draw on their own natural gas reserves. In the future, the countries that are likely to benefit from decarbonization are those that generate a lot of solar and wind power and also have sufficient reserves of land and water, such as Canada and the United States.

“There’s no getting around the fact that we need to make agricultural demand for nitrogen more sustainable in the future, both for meeting climate targets and for food security reasons,” Gabrielli says.

The war in Ukraine is affecting the global food market not only because the country normally exports a lot of grain, but also because the conflict has driven natural gas prices higher. This in turn has caused prices for nitrogen fertilizers to rise. Even so, some fertilizer producers are known to have ceased production, at least temporarily, because the exorbitant cost of gas makes production uneconomical for them.

The research appears in Environmental Research Letters.

Source: ETH Zurich

The offspring of lactating mice missing fiber in their diet may be highly prone to developing obesity, a new study shows.

Those offspring lack microbial diversity in their gut and have low-grade inflammation, the researchers report.

The findings in the journal Cell Host & Microbe could help explain why obesity is increasing, especially in children. However, because the experiment was conducted in mice, the researchers can only speculate how much the results translate to humans.

“As long as young mice were maintained on a standard diet, there was no difference in their weight or other metabolic parameters, regardless of whether or not their mother ate fiber,” says senior author Andrew Gewirtz, professor in the Institute for Biomedical Sciences at Georgia State University.

“But striking differences occurred when they were exposed to a Western style diet. The mice from the fiber-deprived mothers gained striking amounts of weight. The mice from the mothers who had the fiber diet gained only small amounts of weight on this diet.”

A Western style diet, also known as a fast food diet or obesogenic diet, is high in fat and low in fiber. The standard diet that young mice are raised on is a relatively healthy, mostly plant-based diet with a small amount of animal products.

If these results translate to humans, it could help explain cases in which adolescents have very easy access to fast food diets, but some exhibit large increases in adiposity while others remain fit and lean.

The study also found that if mothers were not consuming fiber, then the offspring didn’t get particular bacteria. If offspring don’t have those bacteria, or unless the bacteria are deliberately administered, the fiber by itself doesn’t provide a health benefit. The fiber is only beneficial if bacteria are there to metabolize it, Gewirtz explains.

The researchers studied the offspring’s fecal matter to determine the bacteria they were missing.

“They’re missing beneficial bacteria that help keep out inflammatory bacteria,” says lead author Jun Zou, a research assistant professor in the Institute for Biomedical Sciences. “The beneficial bacteria do two particular things. They can metabolize the fibers to produce beneficial products such as short-chain fatty acids and exclude bacteria that are pro-inflammatory.”

One limitation of the study was the way the experiments were performed. The mice were kept in cages in a research facility, so they didn’t have other ways of acquiring these beneficial bacteria, unless they were deliberately administered to them. This differs from human experience. Even if a child’s mother didn’t eat fiber, that child might be able to play with other children at daycare and acquire these bacteria.

“That’s one reason that our findings might not apply to humans, but we just don’t know,” Gewirtz says.

Next, the researchers want to understand the mechanism behind why some mice are so prone to gain weight when exposed to obesogenic diets and then develop simple approaches to prevent passing along an unhealthy microbiome. For instance, perhaps a pregnant woman could be given dietary supplements of fiber, probiotics, or a combination of the two.

Additional authors are from the Center for Inflammation, Immunity and Infection at the Institute for Biomedical Sciences. The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) of the National Institutes of Health and American Diabetes Association funded the work.

Source: Georgia State University