Culture

BINGHAMTON, NY -- Bacterial infections have become one of the biggest health problems worldwide, and a recent study shows that COVID-19 patients have a much greater chance of acquiring secondary bacterial infections, which significantly increases the mortality rate.

Combatting the infections is no easy task, though. When antibiotics are carelessly and excessively prescribed, that leads to the rapid emergence and spread of antibiotic-resistant genes in bacteria -- creating an even larger problem. According to the Centers for Disease Control and Prevention, 2.8 million antibiotic-resistant infections happen in the U.S. each year, and more than 35,000 people die from of them.

One factor slowing down the fight against antibiotic-resistant bacteria is the amount of time needed to test for it. The conventional method uses extracted bacteria from a patient and compares lab cultures grown with and without antibiotics, but results can take one to two days, increasing the mortality rate, the length of hospital stay and overall cost of care.

Associate Professor Seokheun "Sean" Choi -- a faculty member in the Department of Electrical and Computer Engineering at Binghamton University's Thomas J. Watson College of Engineering and Applied Science -- is researching a faster way to test bacteria for antibiotic resistance.

"To effectively treat the infections, we need to select the right antibiotics with the exact dose for the appropriate duration," he said. "There's a need to develop an antibiotic-susceptibility testing method and offer effective guidelines to treat these infections."

In the past few years, Choi has developed several projects that cross "papertronics" with biology, such as one that developed biobatteries using human sweat.

This new research -- titled "A simple, inexpensive, and rapid method to assess antibiotic effectiveness against exoelectrogenic bacteria" and published in November's issue of the journal Biosensors and Bioelectronics -- relies on the same principles as the batteries: Bacterial electron transfer, a chemical process that certain microorganisms use for growth, overall cell maintenance and information exchange with surrounding microorganisms.

"We leverage this biochemical event for a new technique to assess the antibiotic effectiveness against bacteria without monitoring the whole bacterial growth," Choi said. "As far as I know, we are the first to demonstrate this technique in a rapid and high-throughput manner by using paper as a substrate."

Working with PhD students Yang Gao (who earned his degree in May and is now working as a postdoctoral researcher at the University of Texas at Austin), Jihyun Ryu and Lin Liu, Choi developed a testing device that continuously monitors bacteria's extracellular electron transfer.

A medical team would extract a sample from a patient, inoculate the bacteria with various antibiotics over a few hours and then measure the electron transfer rate. A lower rate would mean that the antibiotics are working.

"The hypothesis is that the antiviral exposure could cause sufficient inhibition to the bacterial electron transfer, so the readout by the device would be sensitive enough to show small variations in the electrical output caused by changes in antibiotic effectiveness," Choi said.

The device could provide results about antibiotic resistance in just five hours, which would serve as an important point-of-care diagnostic tool, especially in areas with limited resources.

The prototype -- built in part with funding from the National Science Foundation and the U.S. Office of Naval Research -- has eight sensors printed on its paper surface, but that could be extended to 64 or 96 sensors if medical professionals wanted to build other tests into the device.

Building on this research, Choi already knows where he and his students would like to go next: "Although many bacteria are energy-producing, some pathogens do not perform extracellular electron transfer and may not be used directly in our platform. However, various chemical compounds can assist the electron transfer from non-electricity-producing bacteria.

"For instance, E. coli cannot transfer electrons from the inside of the cell to the outside, but with the addition of some chemical compounds, they can generate electricity. Now we are working on how to make this technique general to all bacteria cells."

Children engrossed in popular kids' TV programmes such as Peppa Pig, or films like Toy Story or Frozen, are exposed to up to nine incidents of pain for every hour of TV watched, according to new research from psychologists.

A new study - published today [Wednesday 2 December 2020] in the international journal Pain from researchers at the universities of Bath (UK) and Calgary (Canada) - analysed how characters' experiences of pain were depicted across different media aimed at 4 to 6-year olds.

The team behind the research were interested in assessing what painful incidents characters were subject to, as well as how they and others around them responded.

Their analysis looked at 10 family movies from 2009 onwards (Despicable Me 2, The Secret Life of Pets, Toy Story 3 & 4, Incredibles 2, Inside Out, Up, Zootopia, Frozen and Finding Dory), as well as popular kids' TV programmes (Sofia the First, Shimmer and Shine, Paw Patrol, Octonauts, Peppa Pig, Daniel Tiger's Neighbourhood).

These programmes were chosen to represent either girl-focused, boy-focused or gender-neutral TV series (dependent on the key characters).

Over the 10 movies and six TV series (which equated to over 52 hours of film / TV), the researchers identified:

454 painful incidents - a mean of 8.66 incidents of pain per hour.

Violent pain or injury being the most common type of pain depicted (occurring in over two-thirds of instances - 79%).

Boy characters much more likely to experience severe pain in comparison with girl characters (according to facial expressions).

Examples of everyday pain (i.e. a character falling over or bumping their knee), being much less common, represented in only 20% of incidents.

A general lack of empathy from other characters in responding to pain: 75% of painful instances were seen by others, yet in 41% of cases those witnessing it did not respond or where they did they were generally not empathetic.

Researchers say this work matters because what children watch on TV shapes and models their behaviours. They want producers to use their influence to re-think how pain is portrayed in order to better equip young people to cope with common, everyday pain which they are more likely to experience but is often forgotten and misunderstood. Indeed, how children's pain is often sidelined was a topic highlighted in a recent and significant Lancet Commission report, also authored by pain researchers from the University of Bath.

Dr Abbie Jordan of the Department of Psychology and Centre for Pain Research at the University of Bath explained: "How children experience, model, understand and manage pain has real lasting consequences for them as individuals but also for all of us across wider society. Pain, in particular chronic pain, can have hugely debilitating effects on the lives of children and young people right through into adulthood.

"Part of the challenge in this is how we talk about pain. We know children spend increasing amounts of time watching these influential programmes and films and that what they depict feeds through to their understanding and awareness of an issue. When it comes to pain, as we see from this study, the picture presented by these media is not reflective of children's common experiences, instead focusing much more on extreme and violent pain.

"Our assessment is that these programmes could do much more to help children understand pain by modelling it in different ways and crucially by showing more empathy when characters experience pain. That's important for how children interact with others when one of them experiences pain, such as when a friend might fall over in the playground or when they go to the doctors for routine vaccinations."

Lead researcher, Dr Melanie Noel, Associate Professor of Clinical Psychology from the University of Calgary said: "We examined shows and movies that millions of young children in North America and beyond are watching. The findings were, frankly, shocking.

"It is undoubtable that the media is a powerful force in how children learn about the world. The way pain is unrealistically portrayed is teaching young children that pain is not worthy of help or empathy from others, and that it will be experienced and responded to differently if you are a boy or a girl. We have a responsibility to change these societal narratives about pain."

This work was funded by the Alberta Children's Hospital Research Institute and is available via the journal Pain: 10.1097/j.pain.0000000000002086.

Cancer cells spread by switching on and off abilities to sense their surroundings, move, hide and grow new tumours, a new study has found.

This sensitivity to their surroundings is the key ability that makes small numbers of cancer cells better at spreading than other cells in a tumour, scientists at the University of Reading discovered.

The researchers developed a new method combining evolutionary biology and artificial intelligence techniques to study the movement and shape of cancer cells in more detail than ever, to learn why some can move more easily to different parts of the body and grow new tumours.

They found some cells displayed an apparent 'awareness' and ability to react to their surroundings, that was previously thought to be lost in of cancer. This means they may be able to adapt their shape to navigate barriers like blood vessel walls or other competing cells far more efficiently in order to replicate elsewhere.

The findings, published in the journal Proceedings of the Royal Society B, may help to explain why some cancers prove more aggressive than others, and could in the future allow doctors to target these 'super cells' before they spread, giving future cancer patients a greater chance of recovery.

George Butler, a mathematical biologist at the University of Reading who led the study, said: "Unlike healthy human cells, cancer cells were thought to lose their sense of what is around them early in cancer progression, meaning they are effectively blindfolded to their surroundings, focusing instead on replicating to form the primary tumour. Our observations showed for the first time that some cancer cells are able to switch this awareness back on, removing the blindfold to help them move to other locations more efficiently.

"These more spatially-aware cells react by changing shape when they encounter objects, perhaps allowing them to slide past other cells, through membranes into the blood stream and arrive in other parts of the body, where they switch back into replication mode and form new tumours."

Scientists first put a sample of breast cancer cells through a natural selection process in order to evolve sets with enhanced movement or colonisation traits.

Some cells were put into an 'obstacle course', mimicking movement around a human body, with the most successful separated into a group with strong mobility traits. Others were allowed to grow in a small piece of rat lung, resembling the kind of tissue where tumours form, to form a group of strong colonisers.

The two groups of cells were compared against a control group in the lab so scientists could examine the differences between them in detail to learn what makes some better at moving than others.

A computer programme was used to observe the behaviour of the cells in plastic dishes, to analyse their shape and movement far more quickly than a human could.

The mobile group of cells that were more closely packed together were seen to change shape more rapidly to avoid neighbouring cells, while they changed shape less frequently in more sparse environments. This suggests they are able to raise or lower their spatial awareness depending on their surroundings to make them more efficient in all environments.

The new methods of computer vision analysis developed by the team could also be used in other contexts, for example to measure the formation of blood clots or track the movements of sperm cells.

Whether in the workplace or our personal lives, most people have a strong preference for balanced conversations, where each person is able to "get their two cents in." In fact, new research published in Language and Speech shows that people take corrective action to ensure a two-way flow of conversation when situational factors, like defined roles for working together on a task, create an imbalance in how each person is able to contribute.

This corrective behavior had never before been identified or described. The researchers at UC Santa Cruz who discovered it are calling it "reciprocity in conversation." And in settings where people are working together on a task, it's actually associated with higher levels of task enjoyment. This could have fascinating implications for employee morale in work settings, but there's a catch. In order for conversation reciprocity to take place, the people collaborating on a task must make time to incorporate small talk into their work.

Andrew Guydish, a Ph.D. student in cognitive psychology and lead author on this research, said the findings couldn't have come at a better time, because they may be able to help improve remote work environments.

"An average workday now is getting the team together into a virtual meeting, where there's a very clear goal and task," Guydish said. "You're not talking to coworkers at their desk or in the hall. Everything is structured, and everything is essentially a task nowadays. So this research highlights the importance of perhaps trying to institute moments throughout the day with unstructured chat time."

It's in those moments that reciprocity works its magic. Typically, when peers are working together on a task that requires one to direct the other, it creates a natural imbalance in the conversation, where the person in the leadership role ends up doing most of the talking. But if the participants also have unstructured time available, the person leading the task-based conversation can use the opportunity to pull back on their contributions, essentially yielding air time during small talk to the other participant.

That's reciprocity. It helps balance the scales of the overall interaction. And the closer participants get to achieving balance, the higher their levels of enjoyment will be related to the task at hand.

To make this discovery, the research team--which included Guydish, psychology professor Jean Fox Tree, and anticipated 2021 Ph.D. graduate Trevor D'Arcey--analyzed an open-source UC Santa Cruz dataset called the Artwalk Corpus. It's a collection of transcripts from an experiment where one person in a lab was connected with another via video call and tasked with directing them on a walk around downtown Santa Cruz to find and photograph public art.

Researchers reviewed the transcripts from 69 artwalk conversations to identify both task-based and "off-task" communications. Then they determined the contribution balance of each participant, based on who said more words or took longer speaking turns, for each type of communication. In comparing the two, they discovered reciprocity. And when they reviewed the results of post-participation surveys, they found that more balanced conversations, with high levels of reciprocity, had higher reported levels of task enjoyment.

These findings add a new dimension to psychologists' understanding of the importance of balanced communications in collaborative settings. Prior research by Professor Jean Fox Tree, who specializes in psycholinguistics, has also shown that conversational imbalances can have negative effects on task performance by limiting feedback and engagement.

"To understand this, you could draw an analogy to a classroom," said Fox Tree. "Getting feedback from the class tells the professor how they should be explaining something, and that helps everyone in the class, not just the one person who's asking the question."

But the most effective strategies for achieving these benefits are not always intuitive. Prior research on task-based communications found that if roles and power dynamics are merely rotated during a task, the person originally assigned the leadership role often carries forward a tendency to dominate the conversation. Reciprocity shows that the way to bring balance in teamwork settings may not be switching roles, but rather removing the roles entirely and making time to just connect on a personal level.

Co-author Trevor D'Arcey said he thinks this research shows that people are "generally trying to be considerate of each other." There may just be something about small talk that gives us a boost in the right direction.

The multicentre study, in which Berufsgenossenschaftliches Universitätsklinikum Bergmannsheil, Hospital of Ruhr-Universität Bochum (RUB), played a leading role, was published in the Journal of Internal Medicine on 12 November 2020.

Serious dysfunction of the heart muscle

Takotsubo cardiomyopathy - also known as stress cardiomyopathy or broken heart syndrome - has only been known as a clinical condition for about 30 years. It is characterised by an acute, serious functional disorder of the heart muscle, usually triggered by an extreme emotional and psychological stress situation. If detected at an early stage and treated correctly, the prognosis is generally favourable for most patients. However, the acute phase of the disease can lead to complicated and even life-threatening progressions. Researchers have long suspected that there is a close correlation between the occurrence of Takotsubo cardiomyopathy and diseases of the thyroid gland. A research group from Bochum and Mannheim has now systematically tested patients with Takotsubo syndrome for their thyroid metabolism in a large number of cases and compared them with healthy people and patients who have had a heart attack.

Using artificial intelligence and systems biology models, a strong correlation was found between thyroid function and Takotsubo syndrome - in two subforms. One form, the so-called endocrine type, is an overactive thyroid gland that promotes the risk of a heart disease. The second form, the so-called stress type, is caused by an elevated target value of thyroid regulation, which is probably directly related to the stress event. Here, no direct effect of the thyroid hormones on the heart can be proven.

How hormones influence heart sensitivity

"It has not yet been understood why stress events have very different effects on the heart," explains Dr. Assem Aweimer, senior physician at the cardiology clinic in Bergmannsheil. "The results of our study provide a new explanatory model that traces increased sensitivity of the heart muscle to stress hormones back to sensitisation by thyroid hormones." Associate professor Dr. Johannes Dietrich, senior physician at the medical hospital I in Bergmannsheil, adds: "The results of the study highlight the importance of psychoendocrine connections even in severe diseases. In the future, thyroid function could serve as a biomarker for the individual mechanism of Takotsubo syndrome and help optimise personalised drug therapy."

Below please find a summary and link(s) of new coronavirus-related content published today in Annals of Internal Medicine. The summary below is not intended to substitute for the full article as a source of information. A collection of coronavirus-related content is free to the public at http://go.annals.org/coronavirus.

Black and Hispanic populations in the U.S. experiencing disproportionately higher rates of COVID-19

Recent data suggest the impacts of COVID-19 vary among U.S. racial and ethnic groups. Authors from the VA Evidence Synthesis Program, Oregon Health & Science University, and the National Institutes of Health conducted a systematic review to synthesize evidence on racial and ethnic disparities during the pandemic.

The data showed African American/Black and Hispanic populations experience disproportionately higher rates of SARSCoV-2 infection and COVID-19-related mortality but similar rates of case fatality. The authors call for urgent interventions to mitigate these disparities. The findings are published today in Annals of Internal Medicine. Read the full text: https://www.acpjournals.org/doi/10.7326/M20-6306.

Media contacts: A PDF for this article is not yet available. Please click the link to read full text. The lead author, Katherine Mackey, MD, MPP, can be reached at through either Daniel E. Herrigstad at daniel.herrigstad@va.gov (503-402-2975) or through Erik Robinson at 503-494-7986.

Many residents of flood-prone areas of rural Nicaragua face uncertain economic futures each season. In a new paper, EGC faculty affiliate Kevin Donovan and co-author Wyatt Brooks of Arizona State University examine the role of footbridges in providing rural households reliable access to larger and higher-paying urban labor markets. They find that bridge construction increases integration, leading to substantial positive economic impact on rural economies.

The paper underscores the increased benefits of rural integration in the context where income is derived both from farming and labor markets - a common feature of households in developing countries. Moreover, it analyzes the spillover effects of improved access to the labor market on the agricultural economy and shows that bridges might have a compounding positive impact: not only does labor income rise, but agricultural investment increases along with increased profits.

In Nicaragua, both policymakers and residents cite flooding and the resulting isolation of villages as a critical development constraint. During periods of flooding, villagers are cut off from access to outside markets as crossing the river carries a risk of injury or death. Since most rural households are active in the labor market, inaccessible outside labor markets during floods limit choices available and incomes earned.

The researchers worked with an NGO to identify 15 villages in similar need of a bridge. Out of this group, bridges were built in six villages based on the feasibility criteria comprising the characteristics of the riverbed - a feature uncorrelated with any relevant village characteristics. In this quasi-experimental setting, the researchers could compare outcomes between these two sets of villages (i.e., those with and those without a bridge) using causal inference.

The researchers collected data from both annual surveys with all households in each of the 15 villages and biweekly surveys with a subset of households to understand the contemporaneous impact of flooding on household outcomes.

A bridge eliminates the loss of income during floods

In the absence of a bridge, a flood depresses weekly labor market earnings by 18 percent, and increases the probability of reporting no income from 25 percent to 32 percent compared to a week without a flood. When a bridge was constructed, both of these effects disappeared. Hence, the bridge offsets the negative impact of floods on labor income.

Certain access to outside labor markets increases labor income in non-flood periods by expanding choices

The presence of a bridge also increases labor income for households in non-flood periods by influencing choices. Men shift their time from relatively lower-paying jobs in the village to higher-paying jobs outside the village, while women increase their participation in the labor force by 65 percent. Moreover, those who stay in the village for work benefit from the general equilibrium increase: their daily wages rise as village labor supply declines.

Agricultural productivity and profits rise as farmers redirect resources toward investment

In villages with a bridge, farmers spend nearly 60 percent more on fertilizers, and farm profits increase by 75 percent. Protected from unpredictable fluctuations in income induced by floods, villagers are free to spend a larger part of their precautionary savings on productive farm activities.

Agricultural storage declines from 90 to 80 percent of the harvest, suggesting that farmers sell a greater share of their harvest and use the proceeds to invest more in their farms. These results imply that a lack of access to the outside market may have a substantial impact on long-term agricultural decisions in rural economies.

With a bridge, the increase in welfare is larger than the increase in income due to the ability to mitigate risk

According to a model produced by the authors, the introduction of the bridge increases consumption-equivalent welfare by 11 percent. This increase in welfare comes both from an increase in consumption and the decrease in the volatility of consumption. This underscores the importance of reduction in risk that comes with the presence of a bridge.

Bridges are highly cost-effective

The authors find that bridges have an internal rate of return of nearly 20%, since each bridge costs about $40,000 (or C$1,100,000), generates an annual benefit of $7800 (or C$217,000) and lasts at least 40 years. Spillover effects are critical to this calculation. A full third of this internal rate of return is due to the increase in farm profit alone. Given that other benefits are not measured comprehensively, this is likely a conservative estimate of the actual returns.

Fine particulate matter (PM2.5), the tiny particles responsible for hazy air pollution, are detrimental to children's health even inside the classroom. Mounting evidence has linked chronic exposure with poor academic performance in K-12 students. Until now, no research had examined the impact of "peak" air pollution events, the 24-hour spikes of extremely high PM2.5 levels. For students in Salt Lake County, Utah, these episodes are a dangerous reality--the county's largest city, Salt Lake City, was among the top 10 most polluted American cities for short-term particle pollution in the latest American Lung Association report.

In a new study, University of Utah researchers found that more frequent peak air pollution exposure was associated with reduced math and English language arts (ELA) test scores for third graders in all primary public schools in Salt Lake County during the 2016-2017 year. The minimum peak pollution levels in this study are below what the U.S. Environmental Protection Agency (EPA) determines are "safe" levels of PM2.5. The results stress the need for legislators to enact policies that reduce the number of peak pollution days, and to advocate for lower federal pollution standards.

"The huge takeaway is that this isn't about school location--it's not just the schools in the most polluted parts of the city. Everyone is impacted by peak pollution," said lead author Casey Mullen, doctoral student in sociology at the University of Utah.

The study highlights the environmental injustice of Salt Lake County's air pollution problem-- schools with a higher proportion of students of color and from households experiencing poverty were exposed to higher mean concentrations of fine particulates and more peak pollution days than were schools serving middle- to upper- class and predominately white students. Though peak exposures had a stronger effect on lower math proficiency in more socially advantaged schools.

"There are so many studies showing us that air pollution damages our brain's cognitive processing ability," said co-author Sara Grineski, professor of sociology at the University of Utah. "Utah has made great strides to lower pollution in the past decades, but we need to keep pushing forward policies to reduce pollution. We already know it will improve Utahns respiratory health, but it also can help kids do a little bit better in schools."

The paper published online on Sept. 22, 2020, in the International Journal of Environmental Research and Public Health. This research was funded by the Interdisciplinary Exchange for Utah Science at the University of Utah.

Air quality impacts test scores

The researchers looked at the Student Assessment of Growth and Excellence (SAGE) math and ELA scores of third graders in 156 primary public schools in Salt Lake County in 2017. They focused on the percentage of students whose scores were lower than grade-level expectations.

In order to ensure that air pollution was the only variable affecting test scores, the researchers created a school disadvantage variable that took into account Title I school status; Hispanic students; the percentage of non-Hispanic minority students who were Black, Asian/Pacific Islander or Native American/Alaska Native; and the percentage of students on free and/or reduce-priced meals. They also accounted for the school's neighborhood context.

"It is important to account for social disadvantage since social factors are tightly linked with standardized test scores. Students from low-income families have additional struggles that don't tend to affect more affluent students, such as food insecurity. Students from racial/ethnic minority backgrounds often have unequal educational experiences in the U.S. In some cases, they are immigrants themselves or the children of immigrants, and they might still be learning English," said Grineski. "These factors influence standardized test scores."

Then, they evaluated each school's chronic and peak air pollution concentrations. For chronic air pollution levels, they analyzed the daily PM2.5concentrations for each school using daily concentrations in the census tract housing each school from the U.S. EPA's Downscaler data. On average, schools had chronic PM2.5 levels of just over 8 micrograms per cubic meter. To establish peak air pollution episodes, the researchers identified the number of days each school was exposed to PM2.5 levels in the 95th percentile of PM2.5 concentrations for the year, which was 23 micrograms per cubic meter. The U.S. EPA's unhealthy air standard is 35 micrograms per cubic meter.

While chronic pollution exposure was associated with lower test scores, the effect disappeared when researchers controlled for the social disadvantage factors. In contrast, the frequency of peak pollution exposure was associated with a higher percentage of students who tested below grade proficiency in math and ELA, even after controlling for social disadvantage.

"Research shows that air pollution is associated with brain cell inflammation. That is well-established," said Mullen. "With that in mind, our study findings suggest that future research should examine if repeated peak exposures to concentrations of fine particulate matter might be more damaging to children's brain functioning than chronic exposures."

Reduce air pollution

The authors suggest that legislators could advance public health initiatives that protect children's exposure to air pollution. The researchers have consulted with urban planners about creating cleaner air routes for children to move around their communities. For the future, the state could improve regulations that would prevent schools from being built in high pollution areas. For now, investing in better air filtration systems in classrooms could help mitigate the poor air quality already exists. In the face of growing evidence that even low PM2.5 concentrations does damage to the human body, legislators should advocate for lower federal air pollution standards.

"Here, with constant air quality issues throughout the seasons, we need to increase awareness about air pollution exposures," Mullen said. "This is a conversation everyone should be having--people need to be informed about what's at stake."

SMU Office of Research & Tech Transfer - Although cities and urban areas only make up a small proportion of the world's land mass, they are home to more than half the global population and that number is going to keep rising. As cities swell to capacity with more and more inhabitants, city planners have turned to technology to cope with the challenges that accompany urban density.

The role of digital technologies in overcoming urban development challenges have become even more apparent in the COVID-19 pandemic, said Mr Desmond Lee, Minister for National Development and Minister-in-charge of Social Services Integration.

"This pandemic has starkly shown us that we need to transform the way we design, build and maintain our city so that we move away from a heavy reliance on manpower and labour, [and that] the use of digital tools and technology has a potential to create good jobs and opportunities for Singaporeans," Minister Lee said.

Minister Lee was the guest of honour at the Dentons Rodyk Dialogue 2020, held online on 25 September 2020. A partnership between Singapore law firm Dentons Rodyk and Singapore Management University's (SMU) Centre for Cross-Border Commercial Law in Asia (CEBCLA), the yearly Dialogue serves as a forum for thought leaders to share ideas and interrogate key trends shaping the future. This year, the Dialogue explored the opportunities and challenges posed by the rise of global smart cities, and was moderated by Mr Philip Jeyaratnam, Global Vice Chair and ASEAN CEO, Dentons Rodyk.

Planning for people in Singapore and beyond

"Even before COVID-19, many cities including Singapore had already been striving to deal with increasingly complex and global problems," Minister Lee said. "We have harnessed data and digital tools to better plan and design urban Singapore, and make our city more green, livable and sustainable."

Some of the technologies Singapore has employed to overcome the challenges of living in a densely populated city state includes the Housing & Development Board's (HDB) Smart Hub, a central data repository which acts as a 'brain' for municipal operations to help HDB's planners better understand the usage patterns of common amenities.

HDB also uses environmental modelling tools and computer simulations to analyse wind flow, solar heat and noise within towns to design and position homes in a manner that conserves energy and optimises resident comfort. "Singapore is an equatorial and very densely urban country, and these technologies can bring about real benefits," said Minister Lee.

These benefits are a topic of particular interest to SMU President Professor Lily Kong, a social scientist who has studied the impact of technologies in smart cities on their inhabitants' lives. In her keynote presentation, Professor Kong explained how the ASEAN Smart Cities Network (ASCN), a network of 26 cities established in 2018 to foster cooperation on smart city development, could best promote the use of smart technologies as a method of city management.

Considering the challenges

While it is tempting to think that digital solutions could be a panacea for problems caused by rapid urbanisation and urban density, it may be necessary to get a deeper understanding of the challenges involved, she said.

"There is the antecedent challenge, the issue of divergent infrastructural developments, privatisation and formalisation of city spaces, power and inequality, vertical and horizontal integration, and the balance between speed and efficacy," said Professor Kong. "These challenges are rooted largely in a single danger - that we forget that cities are not passive backdrops for digital technologies," she said.

In explaining each of the challenges, Professor Kong also stressed the importance of not neglecting material infrastructure development in favour of its digital counterparts. "Efficient bus timetables and smart traffic lights are no substitute for wider roads and fewer potholes," she explained, adding that overemphasising digital development could distract from material improvements and exacerbate existing inequalities.

"Nothing as powerful as technology can be implemented without some impact," added the next speaker, Ms Chantal Bernier, National Practice Leader, Privacy and Cybersecurity at Dentons Canada. "Many of these digital innovations are predicated upon the use of personal information, which is where privacy law is engaged."

While governments are allowed to process personal data without consent when it is necessary, Ms Bernier said that the possibilities afforded by current data collection methods are so immense and varied that the line between necessary to collect and simply convenient have started to blur. According to privacy laws, personal data collected for one purpose cannot be used for another purpose; however, there have been examples of government technology being used by third parties without consent.

"During the London 2012 Olympics, one of the security measures introduced was smart bins with the capacity to push notifications of security alerts to devices of people passing by," she explained. "That was certainly a laudable objective - except that in 2013 it was discovered that a private sector actor was using it to push advertisements, which is inconsistent with the reasons why the bins had been put in."

"Go slow and go small"

Privacy concerns aside, another key consideration for smart city technologies is that they should be inclusive, said Minister Lee. "In our anxiety to go digital, we should not leave behind a whole generation of citizens," he said, sharing the example of a 90-year-old man who requested for help but was directed to a website he was unable to read.

Agreeing, Professor Kong shared that the most important strategy for governments is to focus on the real needs of people. Such inclusive and critical thinking is key to ensure no segment of the population is left behind, she said.

"If we're not addressing fundamental issues in society, then introducing a form of tracking and formalisation actually exacerbates some of the challenges that the poor face," Professor Kong said, citing the example of how, in a particular Third World City context where smart technology was introduced, formal GPS tracking of garbage truck routes prevent their drivers from engaging in simultaneous work on the side to make ends meet.

But for all the challenges that may undermine the transition to smarter cities, there is still plenty of impetus for Singapore to push forward with its digitalisation efforts. "In the coming years, technology and digitalisation will play an even greater role in the life cycle of the urban built environment and infrastructure that we enjoy today," said Minister Lee. "Becoming a smart nation, making it a reality, and bringing everyone along with it, is integral to our future."

To navigate the challenges in the journey towards this digital future, Professor Kong had two pieces of advice: go slow and go small. "Go slow to minimise the potentially negative effects that come with speed," she said. "Smart solutions are not quick fixes to systemic problems; they are a catalysing glue that is only as effective as the policy regime and material environment within which it is deployed."

"Second, go small to minimise the potentially negative effects of transformation. Compared to major transformations, small incremental steps are often more in sync with the material conditions of the city in question."

SMU Office of Research & Tech Transfer - On a fateful April night ten years ago, the Deepwater Horizon oil rig exploded - taking the lives of 11 crew members and triggering the largest marine oil spill in history. Nearly five million barrels of oil spilled into the Gulf of Mexico, polluting around 2,100 kilometres of shoreline and killing thousands of marine mammals.

A federal probe later pinned the explosion on cost-cutting measures by British oil supermajor BP, owner of the doomed rig. Not only did BP pay US$20 billion in fines to resolve claims from the catastrophic spill, but the company was also blocked for two years from seeking new contracts with the US government owing to their perceived "lack of business integrity".

However, BP is not the only corporation to have landed in hot water for its lapses in judgment. In 2018, US tech giant Google was hit with a US$1.7 billion fine for stifling competition in online advertising. Such negative incidents resulting from the unscrupulous behaviour of corporations can be considered as instances of corporate social irresponsibility (CSI).

Yet, little research has been done on the impacts of CSI on the corporations themselves. To address this gap in literature, Drs Chloe Ho, Thu Ha Nguyen and Van Vu examined how negative environmental and social-related (E&S) incidents affected corporate policies in a study published in SSRN.

As part of the Conference on Green and Ethical Finance held from 16 to 18 September 2020, their findings were tackled in the environmental, social and governance (ESG) session chaired by Professor Dave Fernandez, Director of Singapore Management University's (SMU) Sim Kee Boon Institute for Financial Economics (SKBI). The virtual conference was jointly organised by SKBI, Asian Development Bank Institute and the Journal of Banking and Finance.

A financial trail of misbehaviour

According to Dr Vu, a Lecturer at La Trobe University who presented the paper on behalf of her co-authors, existing studies tend to focus on corporate social responsibility (CSR), but there is still no consensus on how such activities influence corporate policymaking. This is partly because CSR activities are typically disclosed by firms themselves, making their reports prone to greenwashing biases that distort the company's true impact, said Dr Vu.

This limitation can be overcome by examining negative E&S incidents. As these incidents are 'exogenous shocks' - that is, they are covered by external news reports - focusing on them avoids the problem of firms self-reporting. "Instead of looking at CSR performance, we looked at negative events and asked: what would happen to the firm's activities following these events?" explained Dr Vu.

To answer their primary research question, the authors collected data on E&S incidents dating from 2010 to 2018 and obtained the financial information of the firms involved. They found that following such incidents, the cash holdings, net equity issuances and capital expenditure of firms decrease, while their net debt issuances and leverage increase to buffer the negative shock of the incident.

According to Dr Vu, these findings suggest that firms tend to follow the pecking order theory. This means that after such incidents, firms first draw down on their internal funds to pay penalties and other reputational costs, after which they rely on debt financing rather than equity financing to manage the scandal. Further investigation by the authors also revealed that firms rely more heavily on long-term debt after E&S incidents, due to the liquidity risk posed by short-term debt.

However, companies appear to react differently to the incidents depending on their financial constraints. "Financially constrained firms are unable to raise additional equity in the equity market, which is why they have to cut back on their capital expenditure," Dr Vu said. "This is in contrast to non-financially constrained firms, who tend to be able to rely on the debt market to raise additional funds. This could explain why they don't have to cut back on their investment."

Proving that a little goodwill goes a long way, the authors also observed that firms with a high CSR reputation were more capable of cushioning the impacts of E&S incidents. This was reflected in the fact that firms with high reputational capital do not change their investment and financing decisions compared to low-reputation firms. "CSR is important in a sense that when the firm experiences a negative incident, there are less adverse effects on their business," Dr Vu said.

Zooming out from firm to industry

While the study of Dr Vu and her colleagues certainly addressed a gap in literature, SMU Associate Professor Liang Hao, who was the discussant of the Dr Vu's paper, suggested that their arguments could have been strengthened by the presence of an overarching theory. "We know that CSR affects corporate policies. What's the one story that can expand the results across five dimensions - cash holdings, net equity issuance, capital expenditure, net debt issuance and leverage?" asked Professor Liang.

For instance, CSR could be framed as a risk-management tool. "You do CSR in advance such that after negative shocks, firms and stakeholders will still view you positively and are less likely to punish you," he explained. Alternatively, CSR could also be used as a strategic signalling tool. "Some firms use CSR as a public-relations strategy to signal that they are actually good firms, even though they experience negative shocks." Regardless of which narrative the authors would have chosen, linking the findings to a particular mechanism would have benefitted the paper, Professor Liang said.

Though the authors report on exogenous shocks, Professor Liang argued that E&S incidents are a wider reflection of the firm's corporate governance quality. "There's a high correlation between E&S and governance. This means that well-governed firms have certain patterns of corporate policies," he explained. "What you're probably capturing is a governance effect rather than an E&S effect. Therefore, the results could be driven by poor governance."

Some firm-level E&S incidents may also be emblematic of wider industry-level issues, Professor Liang suggested. Hence, future research could examine the policies of peer firms that did not experience negative shocks following the E&S incidents of other firms. Incidents at the firm level and at the industry level could also be separately analysed, as the latter are considered more exogenous compared to firm-level incidents, Professor Liang noted.

Urban legends about the origins of canal grass in Panama abound, but the Smithsonian has new evidence that puts the question to rest. Canal grass is an invasive weed, native to Asia. Because its tiny seeds blow in the wind, it readily invades clearings and spreads to form impenetrable stands by budding from tillers and rhizomes. Once established, canal grass is challenging to eliminate. Fire burns the tops and stimulates the roots. Glassy hairs edging its leaf blades cut skin and dull machetes.

The most widespread story is that the Panama Canal Co. imported canal grass (paja canalera or paja blanca in Spanish, Latin name: Saccharum spontaneum L.) for erosion control. In other versions, the U.S. Army brought it to landscape areas for military exercises or it arrived on ships transiting the canal during the 1950s or 1960s. Another study suggested that seeds or fragments of roots may have washed into the canal from a piece of earth-moving equipment from Thailand or Vietnam shipped through the canal in the 1970s.

"These explanations are all unlikely," said Kristin Saltonstall, STRI staff scientist. "The first documentation of its presence in Panama is a report by the Missouri Botanical Gardens from 1948."

A parent of sugarcane, S. spontaneum often arrives in out-of-the-way places as an escapee from breeding collections. Several previous reports from the Tropical Agriculture and Higher Education Research Center suggested that canal grass escaped from a U.S. Department of Agriculture sugarcane breeding program at the Canal Zone Experimental Gardens (now Summit Nature Park) in the early 1940s. Saltonstall's new genetic results support this idea.

In 1939, the U.S. Department of Agriculture sent more than 500 different varieties of sugarcane and close relatives to the Gardens. Breeders may have been concerned that they could be damaged by hurricanes at the sugarcane experimental station in Canal Point, Florida. The plants were allowed to flower in the gardens as part of ongoing sugarcane breeding trials between 1940 and 1945.

Saltonstall compared DNA extracted from leaves of plants she collected in Panama to DNA samples from a large, international collection of sugarcane and sugarcane relatives maintained by colleagues in Australia, including many of the accessions that were likely brought to Panama in 1939.

"The conditions were right, the plants were there and the timing is right," Saltonstall said. "We can never say with 100% certainty that it came from the Gardens, but it certainly looks like it, because DNA from canal grass in Panama is very similar to accessions from Indonesia in the germplasm collection. All of these plants also have high ploidy levels [many copies of the chromosomes in each cell] and come from the same maternal lineage."

Sugarcane is the world's largest crop. In 2018, Panama produced 2.9 million tons of sugarcane. It was first domesticated in Southeast Asia in the eighth millennium B.C. and gradually spread around the world. Today, a hectare of sugarcane (a cross between S. spontaneum and S. officinarum) yields between 30 and 180 tons of sugar. Sugarcane breeders are eager to improve yield by producing hybrids with other species of grasses, but as they continue to experiment, the possibility of escapes like this continues.

"This was not an intentional introduction," Saltonstall said. "No one was thinking about invasive species at that time. More recently there have been escapes in the U.S. in Florida and Louisiana. Germplasm collections need to be monitored and if there is an escape, it needs to be dealt with before it becomes a problem."

Saltonstall will continue to study canal grass, fascinated by the way these large, invasive plants can take over an area and change its whole ecosystem. And as the world's climate changes, Panama may become drier and more subject to fires, which often start in urban patches of canal grass near burning garbage or roads and then burn into the forest and clear new areas for the canal grass to invade. Canal grass can tolerate drier conditions and outcompete other plants that are not resistant to drought, which may give it an advantage if the climate becomes drier.

Current research predicts that by 2025, 1,800 million people are expected to be living in countries or regions with insufficient water resources, and models show increased severity of droughts in years to come. Food insecurity and other consequences of droughts will become intensified, influencing disease vulnerabilities among populations in less-developed countries. New research from Kelly Austin, associate professor of sociology at Lehigh University, explores how droughts shape gender inequalities in the HIV burden, indirectly through increased food insecurity.

The paper, "Drying Climates and Gender Suffering: Links Between Drought, Food Insecurity, and Women's HIV in Less-Developed Countries," is published in Social Indicators Research.

This study builds on previous attempts to explain women's disproportionate share of global HIV cases through biological, cultural and socioeconomic inequalities by bringing the environment and climate-related disasters into the discussion.

"While many infectious diseases like HIV/AIDS do not have a direct link to the environment in their transmission patterns or vectors, disasters such as drought can still have a significant influence on the social conditions that shape and enhance vulnerabilities," said the researchers, adding that hunger and food insecurity are key factors motivating women's engagement in early marriage, commercial sex, transactional sex relationships, and other forms of risky sex engagements.

Using a structural equation modeling approach, Austin and her colleagues were able to test the indirect and direct links between food insecurity and HIV as well as the causal chain of factors involving drought, food insecurity, and women's HIV.

The results from the study found that drought escalates food insecurity, and food insecurity has indirect, negative impacts on women's status, including lower participation in education, higher fertility rates and reduced access to medical care. Since women's status and the use of contraceptives are tightly linked, these impediments directly increase the percentage of HIV cases among women, confirming the researchers' hypothesis.

"Uncovering these mechanisms would not have been possible with more mainstream approaches," said Austin.

It's common to see strict gender norms in place where women are typically the household managers, carrying the responsibility for growing and harvesting food, collecting firewood, fetching water, and other tasks that provide household needs through environmental resources. In less-developed countries, droughts are the most common cause of severe food shortages, affecting agriculture first. As a result, changes to the environment are likely to compromise women's health in these unique ways.

According to the research, when a crisis hits, women are typically the first to sacrifice their own food to ensure their children and others have enough to eat. Food insecurity directly leads to infection risks through nutrient deficiencies. Additionally, food insecurity indirectly intensifies gendered inequalities that limit women's access to healthcare, education, and improved autonomy, potentially putting women in a more vulnerable position of contracting HIV.

"Women in less-developed countries disproportionately bear the burden in terms of ill health when facing food insecurity or a shock or disaster like drought that impacts the ability to get food or harvest food," said Austin. "This information would be useful for policy makers and people working in international development and disaster response."

Overcrowding in emergency rooms is a costly and concerning global problem, compromising patient care quality and experience. In a new study, a researcher from The University of Texas at Dallas investigated whether telemedicine could enhance ER care delivery.

"This longstanding problem is mainly driven by the imbalance between increasing patient flow and the shortage of emergency room capacity," said Dr. Shujing Sun, assistant professor of information systems in the Naveen Jindal School of Management and lead author of the study.

"While the ER is supposed to be a safety net of the health care system, the overcrowding problem has strained this safety net and posits various threats," Sun said. "For example, long waiting times and treatment delays cause adverse patient outcomes, such as high readmission and mortality rates. They also increase financial costs, reduce patients' satisfaction and impair physician efficiency."

In the study, published online Aug. 27 and in the September print issue of the INFORMS journal Information Systems Research, Sun and her colleagues investigated the potential of telemedicine as a generic solution to reduce ER congestion.

Sun said telemedicine, defined as the remote delivery of health care services and clinical information using telecommunications technology, has been gradually adopted in recent years, but there is little evidence on the impact of its applications within the ER setting.

"Telemedicine application in the ER has two distinguishing features from home-based telemedicine," Sun said. "First, patients present in the ER. Second, on-site assistance is available to connect patients and off-site physicians throughout the telemedicine service. Off-site physicians can be within the same hospital, in a different hospital, or even at home, as long as they can connect with emergency patients through videoconferencing tools and have access to patients' health records."

According to the National Hospital Ambulatory Medical Care Survey, from 2000 to 2015, the number of ER visits in the U.S. increased 27% from 108 million to nearly 137 million. With the sharp rise in ER visits and critical shortages of emergency care physicians, ER overcrowding is not abating, particularly as the COVID-19 pandemic strains the capacity of hospitals nationwide.

Using a large data set covering all emergency visits in New York state from 2010 to 2014, the researchers found that the adoption of telemedicine in the ER significantly shortened average length of stay and wait time.

ER telemedicine improves an on-call physician's efficiency through transportation elimination and smoother workflow, which can shorten a patient's wait for physicians.

For example, when there is an in?ux of emergency patients, telemedicine enables on-site nurse practitioners or physician assistants to treat patients with minor conditions under the remote supervision of off-site physicians. Sun said this is important because many hospitals require that all patients be seen by an attending physician. With telemedicine, on-call physicians can work from their office without traveling to the ER. Having an on-call physician available through telemedicine also can speed up the ordering of lab work, so that those processes can start long before they otherwise would, and physicians can pivot to their administrative tasks more quickly in between visits.

The researchers replicated the analysis using annual U.S. hospital data and found that ER telemedicine adoption significantly reduces average wait times documented in Medicare.gov's Hospital Compare, or the average time a patient spends in the ER before being seen by a health care professional. That finding suggests that the reduction in length of stay -- the total time from the first documented time after arrival at the ER to the time the patient is discharged from the ER -- partially comes from the reduction of waiting time.

Telemedicine could achieve greater efficiencies through several channels, Sun said. In addition to more efficient information exchange, the study showed telemedicine can significantly improve ER care delivery through flexible resource allocation, especially when there is a shortage of on-site physician staffing or a hospital lacks certain expertise.

For example, whether to administer tissue plasminogen activator after stroke symptoms is a time-sensitive and complicated medical decision. However, some hospitals lack such expertise. Through a telestroke program, a type of ER telemedicine application, on-site emergency physicians can immediately consult remote stroke specialists to perform real-time diagnoses and recommend treatment plans in a timely manner.

"Although the ER seems to be an unlikely place for telemedicine to play its role, it is happening, and in fact, is very promising," Sun said. "We believe our findings are critical for ERs, considering the unique setting of unscheduled arrivals and unpredictability of patient traffic."

It's important to note that the improvement in care delivery does not come at the expense of care quality or patient cost, Sun said.

The study provides health care decision-makers with a careful examination of the causal implications of ER telemedicine on care delivery efficiency, care quality and medical expenditure.

"Due to the lack of evidence and the inflexibility of reimbursement policy, the adoption rate of telemedicine in the ER remains low and is growing only slowly," Sun said. "Policymakers can incentivize adoption of ER telemedicine by reducing regulatory barriers, such as lifting restrictions regarding cross-state practitioners' licensure and providing better reimbursement coverage."

With the current global COVID-19 pandemic and the expanded use of telemedicine applications in recent months, Sun said telemedicine has shown its promise to protect patients and providers without compromising health care access.

"When more and more hospitals join the resource-sharing network, telemedicine will have great potential to rebalance the geographically imbalanced health care resources and reduce health care access disparity," she said.

The use of telemedicine during the pandemic offers researchers an opportunity to take a more in-depth look. Sun plans to conduct further research to gather a better understanding of whether, how and why telemedicine functions in various health care situations.

We take for granted the fact that feelings such as love, happiness, or pain are described with different words and expressions across languages. But are these differences in the ways we express these feelings in different languages also tied to differences in the sensations themselves? Would a painful event like a stubbed toe or a bee sting hurt less if a bilingual chose to describe or think about it in Spanish as opposed to English?

These sorts of question were central to the development of a recent study by Morgan Gianola, University of Miami psychology graduate student, along with his advisor, Dr. Elizabeth Losin, director of the Social and Cultural Neuroscience lab at the University of Miami, and Dr. Maria Llabre, professor and associate chair of the Department of Psychology at the University of Miami. The study, entitled "Effects of Language Context and Cultural Identity on the Pain Experience of Spanish-English Bilinguals," is published in the journal Affective Science and will appear as part of the journal's special issue on "Language and Affect."

The Social and Cultural Neuroscience lab uses experimental interactions among research participants to assess how social factors, like the language one speaks or the cultural identity they express, can influence pain responses and other clinically relevant behaviors. Gianola joined this lab to research how social environments and cultural learning can be relevant to perceptions as seemingly objective and inherent as pain.

In the study, 80 bilingual Hispanic/Latino participants from the University of Miami and Miami-Dade County communities visited the lab to participate in separate English and Spanish testing sessions; during both sessions, they received a pain-induction procedure, when an experimenter applied painful heat to their inner forearm. The primary difference between the two experimental visits was the language being spoken (English or Spanish), while the painful procedure itself did not change. Participants provided subjective ratings of their pain, and their physiological responses (i.e. their heart rate and palm sweating) were also monitored.

Gianola explained that this study was inspired by previous research in the field of "linguistic relativity," which has shown differences between English and Spanish speakers in cognitive processes like memory for specific events or categorization of objects. These cognitive differences are also seen among bilinguals when they switch between English and Spanish contexts. Gianola hoped to clarify how such psychological differences across languages might also relate to changes in physical and emotional experiences, like pain.

"All of our participants identified as bicultural," said Gianola. "After each experimental session, we had them fill out surveys about things like how often they use each language [English and Spanish] and how strongly they relate to and identify with both the Hispanic and U.S.-American sides of their cultural identity. The interesting thing we found was, rather than participants always showing higher pain ratings in Spanish, for example, they tended to report more intense pain and show larger physiological responses to pain when they spoke the language of their stronger cultural identity."

According to the study findings, participants who engaged more with Hispanic culture showed higher pain when speaking Spanish, while more U.S.-American identified participants reported higher pain in English. People who were fairly balanced in their engagement with U.S.-American and Hispanic culture had pain outcomes that didn't differ much across languages. The study also suggests that bodily responses to the pain played a larger role in determining pain ratings among more Hispanic oriented bilingual participants.

"This study highlights, first, that Hispanic/Latino communities are not monolithic, and that the factors affecting bilinguals' psychological and physiological responses to pain can differ across individuals," said Gianola. "We also see that language can influence such a seemingly basic perception as pain, but that the cultural associations people carry with them may dictate to what extent the language context makes a difference."

Moving forward, the researchers are developing new experiments to further address the role language plays in influencing cognition and perception among bilinguals. As part of a dissertation project, Gianola plans to investigate the brain processes that contribute to the effects found in this most recent study.

While the mesmerizing blobs in a classic lava lamp may appear magical, the colorful shapes move in response to temperature-induced changes in density and surface tension. This process, known as liquid-liquid phase separation, is critical to many functions in living cells, and plays a part in making products like medicines and cosmetics.

Now Princeton University researchers have overcome a major challenge in studying and engineering phase separation. Their system, reported in a paper published Nov. 19 in Physical Review Letters, allows for the design and control of complex mixtures with multiple phases -- such as nested structures reminiscent of Russian matryoshka dolls, which are of special interest for applications such as drug synthesis and delivery.

Their system provides researchers a new way to examine, predict and engineer interactions between multiple liquid phases, including arrangements of mixtures with an arbitrary number of separated phases, the researchers said.

The arrangement of phases is based on the minimization of surface energies, which capture the interaction energies between molecules at the interfaces of phases. This tends to maximize the contact area between two phases with low surface tension, and minimize or eliminate contact between phases with high surface tension.

The new method uses the mathematical tools of graph theory to track which phases contact each other within a mixture. The method can predict the final arrangements of phases in a mixture when the surface energies are known, and can also be used to reverse-engineer mixture properties that give rise to desired structures.

"If you tell us which phases you have and what the surface tensions are, we can tell you how phases will arrange themselves. We can also do it the other way around -- if you know how you want the phases to be arranged, we can tell you what surface tensions are needed," said senior author Andrej Košmrlj, an assistant professor of mechanical and aerospace engineering.

"The approach is very general, and we think it will have an impact on many different fields," from cell biology and pharmaceuticals to 3D printing and carbon sequestration technologies, said Košmrlj.

The work began as the junior paper of Milena Chakraverti-Wuerthwein, a physics concentrator from Princeton's Class of 2020. She was working with Sheng Mao, then a postdoctoral research associate in Košmrlj's group, building on previous research that explored phase-separated mixtures. That work developed a computational framework for predicting the number of separated phases and their composition, but did not systematically investigate the actual arrangements of phases.

Chakraverti-Wuerthwein started drawing examples of multicomponent mixtures, with each phase represented by a different color. At one point, she said, she felt like she was "going in circles," but then "took a step back and thought about the distinguishing feature that makes one of these morphologies different from another. I came up with the idea that it's really the edges where phases are touching each other. That was the birth of the idea of using the graphs," in which each phase is represented by a colored dot, and the lines between dots indicate which phases touch one another in a mixture.

"That was the spark we needed, because once you can represent it in terms of graphs, then it's very easy to enumerate all the possibilities" for different arrangements of phases, said Košmrlj.

Chakraverti-Wuerthwein is a co-lead author of the paper along with Mao, who is now an assistant professor at Peking University in China. Coauthor Hunter Gaudio, a 2020 graduate of Villanova University, helped run simulations to produce all distinct arrangements of four phases during summer 2019 as a participant in the Princeton Center for Complex Materials' Research Experience for Undergraduates program.

"Normally, liquids like to make simple droplets, and not much else. With this theory, one can program droplets to spontaneously organize into chains, stacks, or nested layers, like Russian dolls," said Eric Dufresne, a professor of soft and living materials at ETH Zürich in Switzerland, who was not involved in the research. "This could be useful for controlling a complex sequence of chemical reactions, as found in living cells. The next challenge will be to develop experimental methods to realize the interactions specified by the theory."

Košmrlj is part of a group of Princeton faculty members exploring various facets and applications of liquid-liquid phase separation -- a major focus of an Interdisciplinary Research Group recently launched by the Princeton Center for Complex Materials with support from the National Science Foundation.

In liquid environments, there is a tendency for small droplets to morph into larger droplets over time -- a process called coarsening. However, in living cells and industrial processes it is desirable to achieve structures of specific size. Košmrlj said his team's future work will consider how coarsening might be controlled to achieve mixtures with targeted small-scale structures. Another open question is how multicomponent mixtures form in living systems, where active biological processes and the basic physics of the materials are both contributing factors.

Chakraverti-Wuerthwein, who will begin a Ph.D. program in biophysical sciences at the University of Chicago in 2021, said it was gratifying to see "that this kernel of an idea that I came up with ended up being something valuable that could be expanded into a more broadly applicable tool."