Breast cancer discovery could help stop disease's deadly spread

UNIVERSITY OF VIRGINIA HEALTH SYSTEM

Research News

 

IMAGE: UVA'S SANCHITA BHATNAGAR, PHD, FOUND THAT THE BREAST CANCER ONCOGENE TRIM37 NOT ONLY CAUSES TRIPLE NEGATIVE BREAST CANCER TO SPREAD BUT ALSO MAKES IT RESISTANT TO CHEMOTHERAPY. view more 

CREDIT: DAN ADDISON | UVA COMMUNICATIONS

University of Virginia Cancer Center researchers have identified a gene responsible for the spread of triple-negative breast cancer to other parts of the body - a process called metastasis - and developed a potential way to stop it.

Triple negative breast cancer (TNBC) is an aggressive form of breast cancer that accounts for 40,000 deaths in the United States annually. The majority of these deaths result from resistance to chemotherapy and subsequent aggressive metastases. So UVA researchers asked: What causes a primary tumor to become metastatic? This is an important question in cancer biology because patients with metastatic tumors have the highest death rate.

UVA's Sanchita Bhatnagar, PhD, and her team found that the breast cancer oncogene TRIM37 not only causes the cancer to spread but also makes it resistant to chemotherapy. A new approach she and her colleagues have developed could possibly address both, the researchers hope.

"Despite metastasis being the key reason for failure of cancer therapies, it remains poorly understood. We do not clearly understand what drives the metastatic growth in patients," said Bhatnagar, who was the first to identify TRIM37 as a breast cancer oncogene. "In general, several genes are altered during tumorigenesis. However, whether targeting the same genes will prevent metastatic transition remains to be addressed."

Promising research from Bhatnagar's team shows that targeting TRIM37 prevents metastatic lesions in mouse models. Those findings form the foundation of her lab's current work exploring the role of TRIM37 in racial disparities in triple negative breast cancer. Incidence of the disease is disproportionately higher in African-American women compared with other races, with a 5-year survival rate in African-American patients of only 14% compared with 36% in non-African-American women.

Targeting Triple-Negative Breast Cancer

Bhatnagar and UVA's Jogender Tushir-Singh, PhD, have developed a new approach to stop the effects of TRIM37 and, hopefully, prevent or significantly delay the spread of triple-negative breast cancer. This could also lower the disease's defenses against chemotherapy.

Blocking the gene could benefit approximately 80% of triple negative breast cancer patients, the researchers estimate.

Bhatnagar and Tushir-Singh's approach uses nanoparticles - microscopic balls of fat - to deliver treatment to block TRIM37. These nanoparticles are paired with specially engineered antibodies that bind to the cancerous cells but not to healthy cells. "As soon as the antibody finds the triple negative breast cancer cell, it binds to the receptor and is taken up by the cell," explained Tushir-Singh, of UVA's Department of Biochemistry and Molecular Genetics.

"It is a kiss of death," Bhatnagar said, "that selectively reduces the expression of TRIM37 in cancer cells and prevents the spread."

The approach could be used to deliver targeted treatments for many other cancers as well, the researchers report. "That would not only get the treatment where it needs to be but, hopefully, help prevent unwanted side effects. Besides preventing metastases, it adds selectivity," Bhatnagar said.

"A problem in the field is, how will you give [a nanoparticle treatment] to the patients? Most of these nanoparticles are cleared by the liver, so they never have a chance to really do their job," she said. "In this study, researchers bypassed this issue by delivering nanoparticles by nasal route, increasing the rate of uptake in the lungs - one of the most common metastatic target sites in TNBC patients."

The development of the new approach is in its early stages, but tests with lab mice have offered encouraging indications. "The lungs showed dramatic reduction in metastatic lesions after the treatment in comparison to the mice that received no treatment," Bhatnagar said.

Next Steps

To verify that TRIM37 targeting might offer a potential treatment approach, Bhatnagar teamed up with Tushir-Singh, her husband, to test it in the lab. "And we find that our targeted nanoparticles significantly reduce metastatic lesions in the lungs of spontaneous metastatic murine [mouse] models - both immune compromised and immune sufficient," she said. "This is an important proof-of-concept much needed for the bench-to-clinic transition of these important findings."

Clinically, most women in the early stages of breast cancer are treated with surgery, followed by radiation or chemotherapy. However, metastasis remains a challenging medical problem. Bhatnagar's research offers a potential way to target a driver of metastasis that she hopes will prevent or slow metastatic progression and improve overall survival.

Much more work needs to be done, but Bhatnagar's research is being noticed by pharmaceutical companies interested in exploring the approach's potential. "This is a delivery platform, not only for targeting our protein of interest but for many other chemotherapeutic drugs that can be packaged into the nanoparticles and selectively delivered," Bhatnagar said.

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Findings Published

The researchers have published their findings in the scientific journal Cancer Research. The research team consisted of Piotr Przanowski, Song Lou, Rachisan Djiake Tihagam, Tanmoy Mondal, Caroline Conlan, Gururaj Shivange, Ilyas Saltani, Chandrajeet Singh, Kun Xing, Benjamin B. Morris, Marty W. Mayo, Luis Teixeira, Jacqueline Lehmann-Che, Jogender Tushir-Singh and Sanchita Bhatnagar.

Bhatnagar, a Hartwell Investigator, is supported by the Department of Defense Breast Cancer Research Breakthrough Award (BC170197P1, BC190343P1) and Metavivor Translational Research Award. A provisional patent has been filed for the molecularly targeted nanoparticle design engineered by the Bhatnagar and Tushir-Singh laboratories.

To keep up with the latest medical research news from UVA, subscribe to the Making of Medicine blog at http://makingofmedicine.virginia.edu.

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Glyphosate may affect human gut microbiota

UNIVERSITY OF TURKU

Research News

 

IMAGE: IN GLYPHOSATE-SENSITIVE BACTERIA, THE EPSPS ENZYME IN THE SHIKIMATE PATHWAY IS BLOCKED BY GLYPHOSATE AND THE ESSENTIAL AROMATIC AMINO ACIDS ARE NOT PRODUCED. GLYPHOSATE-RESISTANT BACTERIA ARE NOT AFFECTED BY THE... view more 

CREDIT: PERE PUIGBÒ

Glyphosate is the most commonly used broad-spectrum herbicide. Researchers from the University of Turku in Finland have developed a new bioinformatics tool to predict if a microbe, e.g. a human gut bacterium, is sensitive to glyphosate.

"Glyphosate targets an enzyme called EPSPS in the shikimate pathway. This enzyme is crucial to synthesizing three essential amino acids. Based on the structure of the EPSPS enzyme, we are able to classify 80-90% of microbial species into sensitive or resistant to glyphosate," says Docent Pere Puigbò, developer of the new bioinformatics tool.

Based on the analyses using the new bioinformatics tool, 54% of the human core gut bacterial species are potentially sensitive to glyphosate.

"This groundbreaking study provides tools for further studies to determine the actual impact of glyphosate on human and animal gut microbiota and thus to their health," explains Docent Marjo Helander.

Glyphosate is thought to be safe to use because shikimate pathway is found only in plants, fungi and bacteria. However, glyphosate may have a strong impact on bacterial species in the human microbiome, and several recent studies have shown that perturbations in the human gut microbiome are connected to many diseases. Therefore, the widespread use of glyphosate may have a strong effect on gut microbiomes as well as on human health.

The dominance of this herbicide in the pesticide market is mainly attributed to the use of transgenic crops, such as soy, corn and canola, which are often grown as glyphosate-resistant varieties outside Europe. In Europe, glyphosate is commonly used to desiccate cereal, bean and seed crops before harvest. It is also used to eradicate weeds prior to sowing in no-till cropping systems.

The risk to come across glyphosate residue in food that has been grown in Finland is small, because desiccation of the cereal fields by glyphosate is not allowed in Finland.

A rich and diverse microbial community is living in soil, on plant surfaces, and in animal guts. It is possible that even low glyphosate residue may indirectly affect pest and pathogen occurrence in these communities.

"In addition to bioinformatics, we need experimental research to study the effects of glyphosate on microbial communities in variable environments," Helander adds.

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Gut immune cells may help send MS into remission

UNIVERSITY OF CALIFORNIA - SAN FRANCISCO

Research News

 

An international research team led by UCSF scientists has shown, for the first time, that gut immune cells travel to the brain during multiple sclerosis (MS) flare-ups in patients. These gut cells seem to be playing a protective role, helping drive MS symptoms back into remission.

Scientists know that in MS, other types of immune cells go haywire and attack myelin, crucial insulation material that helps nerve cells communicate with one another quickly and reliably. The resulting damage leads to periodic MS attacks that can leave patients struggling with vision loss, memory problems, pain and other symptoms. These "relapse" symptoms often subside on their own after days or weeks, but medical experts still don't have a good understanding of what flips the switch from flare-up to remission and back again.

The new findings, published November 20, 2020 in Science Immunology, suggest that an unexpected new player might help bring flare-ups under control: immune cells from the gut that express a type of antibody called IgA. In the gut, these cells serve as a critical first line of defense against foreign invaders and, scientists think, help keep the teeming bacteria of our gut microbiome from growing out of control. Recently, a UCSF-led international research team made the surprising discovery that, in animal models of MS, these gut immune cells leave the digestive system and travel to the brain where they appear to help cut inflammation.

"It was a very new idea," said Sergio Baranzini, PhD, a professor of neurology and member of the UCSF Weill Institute for Neurosciences, lead author on the new study. "Nobody thought to look for this type of immune cell."

Now the team, including scientists in Canada, Germany, Sweden and Switzerland, has gone a step further, finding traces of the IgA antibody in the cerebrospinal fluid of MS patients during flare-ups, but not when episodes are in remission. They also found signs of IgA-producing immune cells in donated postmortem brain tissue that had been damaged during MS attacks. The findings confirm for the first time that gut immune cells are involved in MS relapses in humans.

"Only at the time of an attack was there an increase in these cells and the antibodies they produce," Baranzini said. "That really caught our attention."

In the hopes of determining what these gut immune cells were doing in the brain, the team then looked to see what kinds of molecules the IgA antibody reacted to. Recent research has provided evidence that an unhealthy gut microbiome plays a role in MS, when certain potentially damaging species of bacteria proliferate. While the team found that IgA did not bind to myelin protein, it did bind to some of these harmful bacteria species, suggesting that, unlike other immune cells, which are known to cause damage in MS, IgA-expressing immune cells play a protective role, possibly chasing these harmful bacteria to the brain and mounting a defense against them there.

"This opens up a whole new line of research," said Anne-Katrin Pröbstel, MD, a former UCSF postdoctoral researcher, now at the University of Basel in Switzerland and first author on the paper. "I think it has huge potential for therapeutics."

Collaborations within the UCSF Benioff Center for Microbiome Medicine allowed researchers to work with the various bacteria thought to be hallmarks of the MS microbiome, and the work relied heavily on data and biological samples collected through the multidisciplinary UCSF EPIC Study, which has followed hundreds of MS patients over 16 years.

"I think UCSF is one of the only places where we could have done this, because of the access to patient samples that allow us to look at bacteria in the gut, immune cells from the blood, immune cells from the spinal fluid and brain tissue," said Pröbstel. "It's really a unique resource."

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See study online for a full list of authors, funding information, and relevant disclosures.

About UCSF: The University of California, San Francisco (UCSF) is exclusively focused on the health sciences and is dedicated to promoting health worldwide through advanced biomedical research, graduate-level education in the life sciences and health professions, and excellence in patient care. It includes UCSF Health, which comprises three top-ranked hospitals, as well as affiliations throughout the Bay Area. Learn more at ucsf.edu, or see our Fact Sheet.

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Gut-brain axis influences multiple sclerosis

UNIVERSITY OF BASEL

Research News

 

A Basel-led international research team has discovered a connection between the intestinal flora and sites of inflammation in the central nervous system in multiple sclerosis. A specific class of immune cell plays a central role in this newly identified gut-brain axis. The discovery could pave the way for new treatments for MS that target the intestinal flora.

What do you do when your own immune system attacks your nervous system? Newer treatments for the autoimmune disease multiple sclerosis (MS) rely on removing specific immune cells (B cells) from the blood of patients. However, researchers at both the University of Basel and the University Hospital Basel discovered several years ago that it's better not to remove too broad a range of B cells, as this can aggravate the disease.

A new study in the journal Science Immunology sheds more light on this observation: an international team of researchers, led by Dr. Anne-Katrin Pröbstel at the University of Basel and University Hospital Basel, has discovered that specific B cells form a kind of bridge between the intestinal flora and the sites of inflammation in the central nervous system, exerting an anti-inflammatory effect.

"We knew from earlier studies that the composition of intestinal flora plays a role in MS. But how exactly intestinal bacteria and immune cells influence one another was previously unknown," explains Pröbstel, the study's lead author.

Immune cells for gut and brain

At the heart of the new study are IgA-producing B cells, or IgA B cells in short. Immunoglobulin A (IgA) is a class of antibodies that specializes in immune defense of mucous membranes; the IgA B cells are key to intestinal health.

By analyzing stool samples from MS patients and healthy people, the researchers discovered that MS patients have IgA B cells in their intestines that target in particular bacteria typical of MS - i.e. bacteria that are more common in MS sufferers.

In a next step, the researchers analyzed the role of these immune cells during acute flares of the illness in a total of 56 MS patients. They found that IgA B cells accumulated in the cerebrospinal fluid and brain tissue of MS patients with acute sites of inflammation. "Apparently, these immune cells migrate from the intestine to the inflammation sites in the central nervous system, where they release an anti-inflammatory messenger substance," says Pröbstel. "That could explain why the illness worsens if these immune cells are removed from the blood with medication."

Trigger still unknown

What exactly activates the IgA B cells as helpers against MS and triggers their migration from the intestine to the central nervous system is still being investigated. "If we find the trigger for that, we could use it to treat MS," says Pröbstel. For example, it may be conceivable to change the composition of the intestinal flora of MS sufferers in a targeted way in order to mobilize IgA B cells as helpers against inflammation in the nervous system.

In addition to the University of Basel, other participants in the study included the University of California San Francisco, the Technical University of Munich, the universities of Heidelberg, Umeå (Sweden) and Toronto (Canada), and the Max Planck Institute of Colloids and Interfaces in Potsdam. The study was funded among others by the National Multiple Sclerosis Society and the Swiss National Science Foundation.

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Study: Countering hate on social media

SANTA FE INSTITUTE

Research News

 

IMAGE: FIGURE 1 FROM THE PAPER: EXAMPLES OF TWITTER CONVERSATIONS (REPLY TREES) WITH LABELED HATE (RED), COUNTER (BLUE), AND NEUTRAL SPEECH (WHITE). THE ROOT NODE IS SHOWN AS A LARGE SQUARE. view more 

CREDIT: GARLAND ET AL, EMNLP 2020

The rise of online hate speech is a disturbing, growing trend in countries around the world, with serious psychological consequences and the potential to impact, and even contribute to, real-world violence. Citizen-generated counter speech may help discourage hateful online rhetoric, but it has been difficult to quantify and study. Until recently, studies have been limited to small-scale, hand-labeled endeavors.

A new paper published in the proceedings of the 2020 Conference on Empirical Methods in Natural Language Processing (EMNLP) offers a framework for studying the dynamics of online hate and counter speech. The paper offers the first large-scale classification of millions of such interactions on Twitter. The authors developed a learning algorithm to assess data from a unique situation on German Twitter, and the findings suggest that organized movements to counteract hate speech on social media are more effective than individuals striking out on their own. 

The authors will present their paper, "Countering hate on social media: Large-scale classifications of hate and counter speech" during the November 20, 2020, Workshop on Online Abuse and Harms, which is running in conjunction with EMNLP 2020. 

"I've seen this big shift in civil discourse in the last two or three years towards being much more hateful and much more polarized," says Joshua Garland, a mathematician and Applied Complexity Fellow at the Santa Fe Institute. "So, for me, an interesting question was: what's an appropriate response when you're being cyber-bullied or when you're receiving hate speech online? Do you respond? Do you try to get your friends to help protect you? Do you just block the person?" 

To study such questions scientifically, researchers must first have access to a wealth of real-world data on both hate speech and counter-speech, and the ability to distinguish between the two. That data existed, and Garland and collaborator Keyan Ghazi-Zahedi at the Max Planck Institute in Germany found it in a five-year interaction that played out over German Twitter: As an alt-right group took to the platform with hate speech, an organized movement rose up to counter it.

"The beauty of these two groups is they were self-labeling," explains Mirta Galesic, the team's social scientist and a professor of human social dynamics at SFI. She says researchers who study counter-speech usually have to employ hundreds of students to hand-code thousands of posts. But Garland and Ghazi-Zahedi were able to input the self-labeled posts into a machine-learning algorithm to automate large swaths of the classification. The team also relied on 20-30 human coders to check that the machine classifications matched up with intuition about what registers as hate and counter-speech.

The result was a dataset of unprecedented size that allows the researchers to analyze not just isolated instances of hate and counter speech, but also compare long-running interactions between the two.

The team collected one dataset of millions of tweets posted by members of the two groups, using these self-identified tweets to train their classification algorithm to recognize hate and counter speech. Then, they applied their algorithm to study the dynamics of some 200,000 conversations that occurred between 2013 and 2018. The authors plan to soon publish a follow-up paper analyzing the dynamics revealed by their algorithm.

"Now we can resolve a massive data set from 2016 to 2018 to see how the proportion of hate and counter-speech changed over time, who gets more likes, who is retweeted, and how they replied to each other" Galesic says.

The quantity of data, a tremendous boon, also makes it "incredibly complex," Garland notes. The researchers are in the process of comparing tactics for both groups and pursuing broader questions such as whether certain counter-speech strategies are more effective than others.

"What I'm hoping is that we can come up with a rigorous social theory that tells people how to counter hate in a productive way that's non-polarizing," Garland says, "and bring the Internet back to civil discourse."  

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Dogmatic people seek less information even when uncertain

Peer-reviewed | observational study | people

UNIVERSITY COLLEGE LONDON

Research News

 

People who are dogmatic about their views seek less information and make less accurate judgements as a result, even on simple matters unrelated to politics, according to a study led by UCL and Max Planck Institute for Biological Cybernetics researchers.

The researchers say their findings, published in PNAS, point to differences in thinking patterns that lead people to hold rigid opinions.

First author Lion Schulz, a PhD candidate at the Max Planck Institute in Germany who began the research while at UCL, said: "Anecdotally, it seems that dogmatic people are less interested in information that might change their mind. However, it was unclear if this is because a specific opinion is of high importance to them or if more fundamental processes are at play that transcend specific opinions."

Dogmatic people are characterised by a belief that their worldview reflects an absolute truth and are often resistant to change their mind, for example when it comes to partisan issues. This tendency can have societal impacts by polarising political, scientific and religious debates. However, the cognitive drivers of dogmatism are still poorly understood.

To investigate this, the researchers asked over 700 people to perform a simple decision-making task. Participants saw two boxes with flickering dots and had to decide which box contained more of the dots. Critically, after the participants had made an initial choice, the researchers gave them the chance to view another, clearer version of the boxes. They then made a final decision.

Schulz explained: "This mirrors many real-life situations - for example, when we hear a rumour but aren't sure if it's true. Do we share it, or do we check a credible source beforehand?"

Joint first author, Dr Max Rollwage (Wellcome Centre for Human Neuroimaging at UCL and Max Planck UCL Centre for Computational Psychiatry & Ageing Research) said: "By using simple tasks, we were able to minimise motivational or social influences and pin down drivers of altered evidence processing that contribute to dogmatic beliefs."

The task was followed by a comprehensive set of questionnaires that allowed the researchers to measure participants' political orientation and levels of dogmatism.

Dogmatic individuals and moderates did not differ in their accuracy or confidence of their decisions. However, the researchers found that more dogmatic participants were more likely to decline the helpful additional information.

The differences between more and less dogmatic participants were especially large when participants had little confidence in a decision. Senior author Dr Steve Fleming (Wellcome Centre for Human Neuroimaging at UCL, Max Planck UCL Centre for Computational Psychiatry & Ageing Research and UCL Experimental Psychology) said: "Previous work has found that there is a close link between how confident we feel and whether or not we seek out new information. In the current study we found that this link was weaker in more dogmatic individuals."

In general, the reduced search was detrimental, with more dogmatic people being less accurate in their final judgements.

Dr Fleming added: "It is striking that we could detect links between dogmatism about issues such as politics, and information-seeking in a simple online game. This tells us that real-world dogmatism isn't just a feature of specific groups or opinions but may be associated with more fundamental cognitive processes."

The study highlights that simply having corrective information available does not necessarily mean people will consume it.

Schulz said: "This is particularly relevant today. We have never been so free to decide if we have enough evidence about something or whether we should seek out further information from a reliable source before believing it.

"It is also important to stress that the differences between more and less dogmatic people were subtle, and we don't know yet how they would manifest when considering real-world information such as news about political parties. In the end, it's a cautionary tale, whether we think of ourselves as dogmatic or not: when uncertain, it might be wise to check the information again."

The researchers are now trying to further unravel the underlying cognitive algorithms which trigger people to search for further information in situations of uncertainty.

Simple, no-cost ways to help the public care for the commons

News from the Journal of Marketing

AMERICAN MARKETING ASSOCIATION

Research News

 

Researchers from University of Wisconsin-Madison, New York Institute of Technology, University of Iowa, and Cornell University published a new paper in the Journal of Marketing that examines whether it is possible to make people feel as if the property is theirs--a feeling known as psychological ownership--and how this affects their stewardship behaviors.

The study, forthcoming in the Journal of Marketing, is titled "Caring for the Commons: Using Psychological Ownership to Enhance Stewardship Behavior for Public Goods" and is authored by Joann Peck, Colleen Kirk, Andrea Luangrath, and Suzanne Shu.

Maintaining the natural environment is a pressing issue. The intentional care of public goods, such as publicly owned parks, waterways, drinking water, and air quality, has become increasingly difficult. For example, for public parks, it has become more challenging during the pandemic as park services are reduced while the number of people spending time outside has increased. It is widely acknowledged that property that is publicly, versus individually, owned tends to be more neglected by its users - a phenomenon known in economics as the tragedy of the commons.

The most extreme solution to a tragedy of the commons problem is to convert common property into private property so that a single owner has responsibility for its care. As Peck explains, "We wondered whether it is possible to instead make people feel as if the property is theirs--a feeling known as psychological ownership--without any change to legal ownership. The hypothesis is that people who feel as if they own a public resource might be more likely to engage in stewardship behaviors." Leveraging psychological ownership, the researchers developed a series of actionable interventions that managers of public goods can implement to elicit feelings of ownership in users. Four experiments tested this hypothesis.

The first study was at a public lake with kayakers. Floating trash was set in the water where kayakers would see it. As visitors rented kayaks, half were asked to create a nickname for the lake before entering the water. Using binoculars, the researchers observed whether the kayakers tried to pick up the planted trash. Kayakers who gave the lake a nickname felt more ownership of the lake. Most importantly, they were more than five times as likely to try to pick up the planted trash (41% vs. 7% of the other kayakers).

In the second study, participants imagined taking a walk in a park. They were shown a sign at the park entrance that said either "Welcome to the Park" or "Welcome to YOUR Park." Participants who saw the "YOUR park" sign felt more ownership and responsibility for the park, were more likely to pick up trash, and would donate 34% more to the park ($32.35 vs. $24.08).

The third study tested yet a different way to elicit psychological ownership to see if it could increase actual donations. This study involved cross-country ski renters at a state park. As they rented equipment, they received a map. Half of them were asked to plan their route on the map in advance. The prediction was that this investment of time might increase the skiers' psychological ownership of the park and thus increase their donations through the addition of $1.00 to the rental fee. As expected, skiers who planned their routes and therefore felt more ownership donated to the park 2.5 times more often than those who did not plan their routes. They also reported being more likely to volunteer for the park, to donate in the future, and to promote the park on social media.

The fourth study explored whether managers of public goods may be unintentionally discouraging stewardship behaviors. Many parks tout their attendance numbers, but the intuition was that an attendance sign with a large number of people on it might diffuse users' feelings of responsibility. Research participants imagined they were visiting a park and saw either a "the park" or "YOUR park" welcome sign. Then half of them imagined seeing an attendance sign that read "This week, you are visitor #22,452". (Many U.S. parks have over a million visitors annually, so we designed an attendance sign that included an appropriately large number.) Participants were given money for participating, but also had the option to use some of that money for an anonymous donation to the park. As in the prior studies, individuals who felt more ownership of the park donated more to the park. They were also more likely to say that they would volunteer to help the park, including picking up trash. However, these effects were reduced when participants imagined the attendance sign, which possibly suggested the feeling that these other people would take responsibility for the park.

"This research has implications for consumers, organizations caring for public resources, policy makers, and for-profit companies by demonstrating that simple interventions based on increasing psychological ownership can enhance stewardship of public goods. The actionable interventions we designed and tested to increase psychological ownership are inexpensive, novel, and flexible solutions that successfully motivate individual stewardship behaviors" says Luangrath. By fostering visitors' individual feelings of ownership of a public resource, visitors will feel more responsible for it, take better care of it, and donate more time and money for its benefit.

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Full article and author contact information available at: https://doi.org/10.1177%2F0022242920952084

About the Journal of Marketing

The Journal of Marketing develops and disseminates knowledge about real-world marketing questions useful to scholars, educators, managers, policy makers, consumers, and other societal stakeholders around the world. Published by the American Marketing Association since its founding in 1936, JM has played a significant role in shaping the content and boundaries of the marketing discipline. Christine Moorman (T. Austin Finch, Sr. Professor of Business Administration at the Fuqua School of Business, Duke University) serves as the current Editor in Chief.

https://www.ama.org/jm

About the American Marketing Association (AMA)

As the largest chapter-based marketing association in the world, the AMA is trusted by marketing and sales professionals to help them discover what's coming next in the industry. The AMA has a community of local chapters in more than 70 cities and 350 college campuses throughout North America. The AMA is home to award-winning content, PCM® professional certification, premiere academic journals, and industry-leading training events and conferences.

https://www.ama.org

Highly efficient, long-lasting electrocatalyst to boost hydrogen fuel production

Surface oxygen adsorbed during synthesis of the single atomic alloy catalyst stabilizes the catalytic intermediate, ensuring a full cycle of water oxidation

INSTITUTE FOR BASIC SCIENCE

Research News

 

IMAGE: CRYSTAL STRUCTURE OF SURFACE OXYGEN-RICH METAL ALLOY (TOP LEFT). OXYGEN AND HYDROGEN ARE GENERATED DURING A WATER ELECTROLYSIS REACTION (TOP RIGHT). THE DESIGNED CATALYST EXHIBITS THE BEST OXYGEN EVOLUTION ACTIVITY... view more 

CREDIT: IBS

Abundant. Clean. Flexible. Alluring enough to explain why hydrogen, the most common molecule in the universe happens to have its name as part of an national Hydrogen and Fuel Cell Day. Chosen to signify hydrogen's atomic weight of 1.008, the U.S. Department of Energy's Office of Energy Efficiency and Renewable Energy celebrates advances in hydrogen-use technology every October 8 since 2015. When hydrogen is consumed in a fuel cell (which takes the water molecule H2O and seperates it into oxygen and hydrogen, a process called electrolysis), it only produces water, electricity, and heat. As a zero-carbon energy source, the range of its potential use is limitless: transportation, commercial, industrial, residential, and portable.

While traditional hydrogen production processes required fossil fuels or CO2, electrolysis produces "green hydrogen" from water molecules. Since water cannot be split into hydrogen and oxygen by itself, the electrochemical hydrogen-water conversion needs highly active electrocatalysts. The conventional water electrolysis, however, faces technological challenges to improve the efficiency of the water-splitting reaction for the sluggish oxygen evolution reaction. Noble metal-based ruthenium oxide (RuO2) and iridium oxide (IrO2) are used to enhance the oxygen generation rate. However, these noble metal catalysts are very expensive and show poor stability under long-term operation.

Led by Associate Director LEE Hyoyoung of the Center for Integrated Nanostructure Physics within the Institute for Basic Science (IBS) located at Sungkyunkwan University, the IBS research team developed a highly efficient and long-lasting electrocatalyst for water oxidation using cobalt, iron, and a minimal amount of ruthenium. "We used 'amphiphilic block copolymers' to control electrostatic attraction in our single ruthenium (Ru) atom-bimetallic alloy. The copolymers facilitate the synthesis of spherical clusters of hydrocarbon molecules whose soluble and insoluble segments form the core and shell. In this study, their tendency for a unique chemical structure allows the synthesis of the "high-performance" single atomic Ru alloy present atop the stable cobalt iron (Co-Fe) metallic composite surrounded by porous, defective and graphitic carbon shell," says LEE Jinsun and Kumar Ashwani, the co-first authors of the study.

"We were very excited to discover that pre-adsorbed surface oxygen on the Co-Fe alloy surface, absorbed during the synthesis process, stabilizes one of the important intermediates (OOH*) during the oxygen generation reaction, boosting the overall efficiency of the catalytic reaction. The pre-absorbed surface oxygen has been of little interest until our finding," notes Associate Director Lee, the corresponding author of the study. The researchers found that four hour-annealing at 750°C in an argon atmosphere is the best appropriate condition for the oxygen generating process. In addition to the reaction-friendly environment on the host metal surface, the single Ru atom, where oxygen generation takes place, also fulfills its role by lowering the energy barrier, synergistically enhancing the efficiency of oxygen evolution.

The research team evaluated the catalytic efficiency with the overvoltage metrics needed for the oxygen evolution reaction. The advanced noble electrocatalyst required only 180 mV (millivolt) overvoltage to attain a current density of 10 mA (milliampere) per cm2 of catalyst, while ruthenium oxide needed 298 mV. In addition, the single Ru atom-bimetallic alloy showed long-term stability for 100 hours without any change of structure. Furthermore, the cobalt and iron alloy with graphitic carbon also compensated electrical conductivity and enhanced the oxygen evolution rate.

Associate Director Lee explains, "This study takes us a step closer to a carbon-free, and green hydrogen economy. This highly efficient and inexpensive oxygen generation electro-catalyst will help us overcome long-term challenges of the fossil fuel refining process: to produce high-purity hydrogen for commercial applications at a low price and in an eco-friendly manner."

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The study was published online on November 4 in the journal Energy & Environmental Science.

XAOS THEORY

A long distance connection: polar climate affects trade wind strength in tropics

UNIVERSITY OF HAWAII AT MANOA

Research News

 

IMAGE: THE BLUE ICE COVERING LAKE FRYXELL IN THE TRANSANTARCTIC MOUNTAINS COMES FROM MELTED GLACIER WATER. view more 

CREDIT: JOE MASTROIANNI, NATIONAL SCIENCE FOUNDATION

The impact of sea surface temperature variations in the tropical Pacific on global climate has long been recognized. For instance, the episodic warming of the tropical Pacific during El Niño events causes melt of sea ice in far-reaching parts of the Southern Ocean via its effect on the global atmospheric circulation. A new study, published this week in the journal Science Advances by an international team, demonstrates that the opposite pathway exists as well.

Using a hierarchy of climate model simulations, the authors demonstrate the physical pathways via which polar climate variations can affect the trade winds in the tropics.

"Climate signals can propagate from the polar regions to the tropics either via the atmosphere or the ocean," explained Malte Stuecker, co-author and assistant professor in the Department of Oceanography and International Pacific Research Center at the University of Hawai?i at Mānoa. "Our climate model simulations were designed to investigate the relative role of these pathways and whether their importance differs for perturbations originating from the North pole or the South pole."

The authors found that in the most complex model simulations, which include realistic representations of the ocean, atmosphere, land, and sea ice, an anomalous cooling in either hemisphere leads to a strengthening of the tropical trade winds.

Lead author Sarah Kang from the Ulsan National Institute of Science and Technology in South Korea explained the reasoning behind these experiments: "One of the largest sources of uncertainty in the current generation of climate models are biases in the representation of clouds over the cold Southern Ocean. We wanted to explore what effect too much reflection of solar radiation by these clouds to outer space might have on global climate. In addition, large emissions of aerosols in the late 20th century due to industrial activity in the Northern Hemisphere from North America, Europe, and Asia resulted in a slight, temporary reduction of the global warming rate that is due to increasing greenhouse gas emissions."

According to the authors' results, both of these effects could potentially explain why the Pacific trade winds were anomalously strong in recent decades.

"If the communication between the poles and the tropics would only occur via the atmosphere, we would see quite a distinct response in the tropics depending on whether an anomalous cooling arises from the Arctic or the Antarctic," Stuecker added. "This is because the Intertropical Convergence Zone - the largest rainband on Earth - is located to the north of the equator. It effectively blocks a communication from the Arctic to the equator via the atmosphere."

Contrasting experiments with and without a realistic ocean representation, the authors show that enhanced upwelling of cold subsurface water in the eastern tropical Pacific is able to communicate the Arctic cooling towards the tropics and thereby strengthening the trade winds.

An important implication of the results is that reducing uncertainty in simulated extratropical climate may also lead to improved simulation of climate in the tropics. The model hierarchy developed by the authors can be used to further explore two-way interactions between the tropics and polar regions both for future climate projections as well as for interpreting reconstructions of climate states in the geological past.

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GOOD NEWS

Some Amazon rainforest regions more resistant to climate change than previously thought

New observational study demonstrates that increasing air dryness does not reduce photosynthesis in certain very wet regions of the Amazon rainforest, contradicting Earth system models that show the opposite

COLUMBIA UNIVERSITY SCHOOL OF ENGINEERING AND APPLIED SCIENCE

Research News

 

IMAGE: PHOTO WAS TAKEN FROM THE TOP OF THE K34 FLUX TOWER SITE LOCATED 60KM NORTH OF MANAUS, BRAZIL. view more 

CREDIT: XI YANG/UNIVERSITY OF VIRGINIA

New York, NY--November 20, 2020--Forests can help mitigate climate change, by taking in carbon dioxide during photosynthesis and storing it in their biomass (tree trunks, roots, etc.). In fact, forests currently take in around 25-30% of our human-generated carbon dioxide (CO2) emissions. Certain rainforest regions, such as the Amazon, store more carbon in their biomass than any other ecosystem or forest but when forests become water-stressed (not enough water in the soil, and/or air is extremely dry), forests will slow down or stop photosynthesis. This leaves more CO2 in the atmosphere, and can also lead to tree mortality.

The current Earth system models used for climate predictions show that the Amazon rainforest is very sensitive to water stress. Since the air in the future is predicted to get warmer and drier with climate change, translating to increased water stress, this could have large implications not just for the forest's survival, but also for its storage of CO2. If the forest is not able to survive in its current capacity, climate change could greatly accelerate.

Columbia Engineering researchers decided to investigate whether this was true, whether these forests are really as sensitive to water stress as what the models have been showing. In a study published today in Science Advances, they report their discovery that these models have been largely over-estimating water stress in tropical forests.

The team found that, while models show that increases in air dryness greatly diminish photosynthesis rates in certain regions of the Amazon rainforest, the observational data results show the opposite: in certain very wet regions, the forests instead even increase photosynthesis rates in response to drier air.

"To our knowledge, this is the first basin-wide study to demonstrate how--contrary to what models are showing--photosynthesis is in fact increasing in some of the very wet regions of the Amazon rainforest during limited water stress," said Pierre Gentine, associate professor of earth and environmental engineering and of earth and environmental sciences and affiliated with the Earth Institute. "This increase is linked to atmospheric dryness in addition to radiation and can be largely explained by changes in the photosynthetic capacity of the canopy. As the trees become stressed, they generate more efficient leaves that can more than compensate for water stress."

Gentine and his former PhD student Julia Green used data from the Intergovernmental Panel on Climate Change's Coupled Model Intercomparison Project 5 (CMIP5) models and combined them with machine learning techniques to determine what the modeled sensitivity of photosynthesis in the tropical regions of the Americas was to both soil moisture and air dryness. They then performed a similar analysis, this time using observational remote sensing data from satellites in place of the model data, to see how the observational sensitivity compared. To relate their results to smaller-scale processes that could explain them, the team then used flux tower data to understand their results at the canopy and leaf level.

Earlier studies have shown that there are increases in greenness in the Amazon basin at the end of the dry season, when both the soil and air is drier, and some have linked this to increases in photosynthesis. "But before our study, it was still unclear whether these results translated to an effect over a larger region, and they had never been connected to air dryness in addition to light," Green, who is now a postdoctoral research associate at Le Laboratoire des Sciences du Climat et de l'Environnement in France, explained. "Our results mean that the current models are overestimating carbon losses in the Amazon rainforest due to climate change. Thus, in this particular region, these forests may in fact be able to sustain photosynthesis rates, or even increase it, with some warming and drying in the future."

Gentine and Green note, however, that this sensitivity was determined using only existing data and, if dryness levels were to increase to levels that are not currently being observed, this could in fact change. Indeed, the researchers found a tipping point for the most severe dryness stress episodes where the forest could not maintain its level of photosynthesis. So, say Gentine and Green, "our findings are certainly not an excuse to not reduce our carbon emissions."

Gentine and Green are continuing to look at themes related to vegetation water stress in the tropics. Green is currently focusing on developing a water stress indicator using remote sensing data (a dataset that can be used to identify when a forest is under stressful conditions), quantifying the effects of water stress on plant carbon uptake, and relating them to ecosystem traits.

"So much of the scientific research coming out these days is that with climate change, our current ecosystems might not be able to survive, potentially leading to the acceleration of global warming due to feedbacks," Green added. "It was nice to see that maybe some of our estimates of approaching mortality in the Amazon rainforest may not be quite as dire as we previously thought."

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About the Study

The study is titled "Amazon rainforest photosynthesis increases in response to atmospheric dryness."

Authors are: J. K. Green 1,2; J. Berry 3; P. Ciais 2; Y. Zhang 1,4; P. Gentine 1,5

1Department of Earth and Environmental Engineering, Columbia Engineering

2Laboratoire des Sciences du Climat et de l'Environnement (LSCE), Gif sur Yvette, France

3Carnegie Institution for Science, Stanford, CA

4Department of Earth and Environmental Sciences, Lawrence Berkeley National Laboratory

5The Earth Institute, Columbia University

The study was supported by NASA Earth and Space Science Fellowship (NNX16AO16).

The authors declare that they have no competing interests.

LINKS:

Paper: https://advances.sciencemag.org/lookup/doi/10.1126/sciadv.abb7232

DOI: 10.1126/sciadv.abb7232

http://engineering.columbia.edu/

http://advances.sciencemag.org/

https://www.engineering.columbia.edu/faculty/pierre-gentine

https://eee.columbia.edu/

https://eesc.columbia.edu

http://ei.columbia.edu/

https://www.researchgate.net/profile/Julia_Green6

Columbia Engineering

Columbia Engineering, based in New York City, is one of the top engineering schools in the U.S. and one of the oldest in the nation. Also known as The Fu Foundation School of Engineering and Applied Science, the School expands knowledge and advances technology through the pioneering research of its more than 220 faculty, while educating undergraduate and graduate students in a collaborative environment to become leaders informed by a firm foundation in engineering. The School's faculty are at the center of the University's cross-disciplinary research, contributing to the Data Science Institute, Earth Institute, Zuckerman Mind Brain Behavior Institute, Precision Medicine Initiative, and the Columbia Nano Initiative. Guided by its strategic vision, "Columbia Engineering for Humanity," the School aims to translate ideas into innovations that foster a sustainable, healthy, secure, connected, and creative humanity.