Brain

LAWRENCE -- For a geoscientist, the benefits of performing fieldwork are countless. Researching in nature gives geoscientists firsthand contact with the earth's raw materials and a chance to test ideas and develop theories -- as well as to make new discoveries. For this reason, geoscientists often trek to faraway locations, negotiating difficult physical terrain and distinctive cultural landscapes to access geologic features vital to their research.

But there's a problem: For geoscientists from minority and underrepresented populations, fieldwork can prove daunting -- and even physically dangerous. Women scientists could face harassment or sexual assault; scientists with disabilities could find field sites impossible to access; racial minority researchers might face prejudice and bigotry.

But until now, no study has focused on fieldwork accessibility for LGBTQ geoscientists, in spite of obvious hazards. For instance, according to Newsweek, in 2019 there were 71 countries where homosexuality is illegal.

Recently, an investigation from University of Kansas researchers appeared in Eos, a publication of the American Geophysical Union, examining the challenges of fieldwork for LGBTQ geoscientists. Alison Olcott, associate professor of geology, and Matthew Downen, who recently earned his doctorate in geology from KU, surveyed the experience of LGBTQ scientists in "everything from wilderness treks, oceanographic cruises, and class field trips to museum and laboratory visits, trips to research centers, and attending conferences around the world."

They found 55% of the geoscientists who identify as LGBTQ indicated they'd been in an area where they didn't feel safe due to their identity, expression or presentation -- while about a third have refused to do fieldwork due to concerns for personal safety related to their identity.

"There are many places with really excellent geological samples that might not be safe for an LGBTQ+ geologist to go travel," Olcott said. "It's something unrecognized in the field, by academic advisers in particular. It seemed like an unseen, unacknowledged problem in the geosciences, where we're dependent on where the rocks are -- but not everyone is equally safe to go to these places."

The impetus for the study came from Downen, inspired by his years attending a growing LGBTQ social event thrown each year at the Geological Society of America's conference.

"It used to just be a small dinner with maybe 10 to 15 people -- but in the last few years it just skyrocketed," he said. "One year, it was over 60 people, and not everybody could attend. I remember seeing so many new younger people, people my age. There were a lot of different identities and genders represented, and I was floored by all the incredible diversity."

Downen wondered about the experiences of the emerging LGBTQ community in the geosciences, so he began collecting data informally for a presentation to the KU chapter of the organization Out in STEM.

"I was curious to know who really is out there and what the community really looks like within geology," he said. "I also wanted to do this research because it's important for people in the LGBTQ+ community in geology to know there are other people out there like them."

Looking to improve the data, Downen and Olcott conducted a broader, more rigorous survey of geoscientists online. Their results revealed that "many of these scientists felt unseen, unheard and unsupported in their field."

Most striking, the KU researchers found that LGBTQ graduate students in geosciences often aren't adequately supported by faculty advisers, especially as "relative to faculty, students typically have far less control over their field site selection." Their survey found LGBTQ graduate students (29%) are significantly less likely than professors (57%) to have opted out of fieldwork in a specific locality because of safety fears.

"In geology, usually the graduate student is doing a project based off of the adviser's main project," Olcott said. "An adviser will likely say, 'Oh, I have this grant to go to to a field locality and look at these examples.' We were really struck that so many professors had not done a research project because of their identity, but it was only 29% of the graduate students. It seemed like graduate students were being put in a position where they were being made to do things where they felt unsafe, but couldn't say no or didn't feel comfortable saying, 'Hey, I'm not safe here because of who I am.'"

The authors suggest institutions and mentors should provide more resources to LGBTQ graduate students in the geosciences to ensure their security in the field. "People who are advising students and leading field trips or fieldwork need to better educate themselves and be more aware of different policies or just the attitudes in a certain area," Downen said.

Olcott and Downen said faculty mentors and institutions could provide travel guidance and resources geared to LGBTQ personnel prior to fieldwork. In the classroom, professors could confront homophobia by using inclusive language and students' preferred pronouns. Meantime, faculty and staff should offer supportive academic advising, visible allyship and diversity training.

Both authors stressed homophobia and barriers to fieldwork aren't limited to far-flung countries but often are faced much closer to home.

"We're not saying North America and Europe are awesome and everywhere else is terrible for LGBTQ+ geoscientists," Olcott said. "It's a more granular issue -- just because the place on the map is designated friendly, it doesn't mean necessarily that way everywhere."

"If you're traveling globally, a world map showing where your identity could be criminalized is just kind of the most basic thing," Downen said. "Even in the U.S., depending on where you go, it may not be friendly there, either -- that's where some LGBTQ+ geoscientists have reported their worst field experiences due to their LGBTQ+ identity."

DURHAM, N.C. - Researchers at Duke University and the University of California, Los Angeles, have developed a biomaterial that significantly reduces scar formation after wounding, leading to more effective skin healing. This new material, which quickly degrades once the wound has closed, demonstrates that activating an adaptive immune response can trigger regenerative wound healing, leaving behind stronger and healthier healed skin.

This work builds on the team's previous research with hydrogel scaffolds, which create a structure to support tissue growth, accelerating wound healing. In their new study, the team showed that a modified version of this hydrogel activates a regenerative immune response, which can potentially help heal skin injuries like burns, cuts, diabetic ulcers and other wounds that normally heal with significant scars that are more susceptible to reinjury.

This research appears online on November 9, 2020 in the journal Nature Materials.

"The body forms scar tissue as fast as possible to reduce the chance of infection, to reduce pain, and, in larger wounds, to avoid water loss through evaporation," said Maani Archang, a first author on the paper and an MD/PhD student in the Scumpia and Di Carlo labs at UCLA. "It's a natural process of wound healing."

Current wound-healing hydrogels available for clinical use sit on the surface of the wound, where they act as a dressing and help prevent the wound from drying out. That in turn helps the wound heal faster, generally via scar formation.

In their 2015 Nature Materials paper, the research team, helmed by Duke's Tatiana Segura and UCLA's Dino Di Carlo, developed microporous annealed particle (MAP) hydrogels, which are a microparticle-based biomaterial that can integrate into the wound rather than sit on the skin's surface. The beads within the MAP gel link together but leave open spaces, creating a porous structure that provides a support for cells as they grow across the wound site. As the wound closes, the gel slowly dissolves, leaving behind healed skin.

Although the MAP hydrogels allowed for rapid cellular growth and faster repair, the team noticed that the healed skin had limited complex structures like hair follicles and sebaceous glands. The team was curious whether they could alter their biomaterial to improve the quality of the healed skin.

"Previously we'd seen that as the wound started to heal, the MAP gel started to lose porosity, which limited how the tissue could grow through the structure," says Don Griffin, an assistant professor at the University of Virginia who is a first author on the paper and a former postdoctoral fellow in the Segura Lab. "We hypothesized that slowing down the degradation rate of the MAP scaffold would prevent the pores from closing and provide additional support to the tissue as it grows, which would improve the tissue's quality."

Rather than create an entirely new gel with new materials, the team instead focused on the chemical linker that allowed the scaffold to be naturally broken down by the body. In their original MAP gels, this chemical linker is composed of an amino acid sequence taken from the body's own structural proteins and arranged in a chemical orientation called L chirality. Because this peptide sequence and orientation is common throughout the body, this helps the gel avoid triggering a strong immune response, but it also enables ready degradation through naturally present enzymes.

"Our body has evolved to recognize and degrade this amino acid structure, so we theorized that if we flipped the structure to its mirror image, which is D chirality, the body would have a harder time degrading the scaffold," said Segura, a professor of biomedical engineering at Duke. "But when we put the hydrogel into a mouse wound, the updated gel ended up doing the exact opposite."

The updated material integrated into the wound and supported the tissue as the wound closed. But instead of lasting longer, the team discovered that the new gel had almost entirely disappeared from the wound site, leaving behind just a few particles.

However, the healed skin turned out to be stronger and included complex skin structures that are typically absent in scars. After further investigation, the researchers discovered that the reason for the stronger healing--despite the lack of longevity--was a different immune response to the gel.

After a skin injury, the body's innate immune response is immediately activated to ensure that any foreign substances that enter the body are quickly destroyed. If substances can escape this first immune response, the body's adaptive immune response kicks in, which identifies and targets the invading material with more specificity.

Because the original MAP gel was made with the common L peptide structure, it generated a mild innate immune response. But when the team placed the reformulated gel into a wound, the foreign D chirality activated the adaptive immune system, which created antibodies and activated cells including macrophages that targeted and cleared out the gel more quickly after the wound closed.

"There are two types of immune responses that can occur after injury--a destructive response and a more mild regenerative response," said Scumpia, an assistant professor in the division of dermatology at UCLA Health and the West Los Angeles VA Medical Center. "When most biomaterials are placed in the body, they are walled off by the immune system and eventually degraded or destroyed. But in this study, the immune response to the gel induced a regenerative response in the healed tissue."

"This study shows us that activating the immune system can be used to tilt the balance of wound healing from tissue destruction and scar formation to tissue repair and skin regeneration," said Segura.

Working with Maksim Plikus, a regenerative tissue expert at the University of California, Irvine, the team also confirmed that key structures, like hair follicles and sebaceous glands, were correctly forming over the scaffold. When the team dug into the mechanism, they found that the cells of the adaptive immune system are required for this regenerative response.

As the team continues to study the regenerative immune response to their gel, they are also exploring the possibility of using the new MAP hydrogel as an immunomodulatory platform. "The team is now exploring the best way to release immune signals from the gel to either induce skin regeneration or develop the hydrogel as a vaccine platform," said Scumpia.

"I am excited about the possibility of designing materials that can directly interact with the immune system to support tissue regeneration" said Segura. "This is a new approach for us."

Many children and young people with obsessive thoughts and compulsions experience that their OCD, anxiety and depressive symptoms worsen during a crisis such as COVID-19. This is shown by a new research result from Aarhus University and the Centre for Child and Adolescent Psychiatry, Central Denmark Region. The findings have been published in BMC Psychiatry.

Trauma and stress can trigger or worsen OCD. Researchers already know this. They have also shown us that COVID-19 may be associated with adults developing psychiatric disorders. But we do not know much about what the corona crisis means for children and young people.

A team of researchers from Aarhus University and the Centre for Child and Adolescent Psychiatry, Central Denmark Region, therefore decided to examine how children and young people with OCD experience the crisis. Professor, Department Chair Per Hove Thomsen led the research project.

Condition worsened

During the spring of 2020, the researchers sent a questionnaire to two groups of children and young people between the ages of seven and 21. One group had been diagnosed with OCD in a specialised OCD section at the Centre for Child and Adolescent Psychiatry - and all had been in contact with a therapist at the hospital. The other group was identified through the Danish OCD Association. The majority of these children and young people had been diagnosed years ago. A total of 102 children responded to the questionnaire.

"Their experience was that their OCD, anxiety and depressive symptoms worsened during a crisis like COVID-19. This worsening was most pronounced for the group identified through the OCD Association," says Per Hove Thomsen.

Almost half of the children and young people who belonged to the first group reported that their symptoms had become worse, while a third of them replied that their anxiety had worsened and a third that their depressive symptoms had worsened. And of these, almost a fifth experienced that both symptoms had got worse. In the other group, 73 per cent reported that their condition had worsened, just over half that their anxiety had worsened, and 43 per cent answered that the depressive symptoms had increased.

Disinfect and wash hands

Judith Nissen, who is a consultant, was also one of the driving forces behind the study. She emphasises that it is no coincidence that the researchers have chosen to study OCD.

"The disorder is particularly interesting to study in relation to the COVID-19 pandemic, because OCD is a disorder with many different clinical expressions, including not least health anxiety, fear of bacteria and dirt, and excessive hand washing/use of disinfection. It's therefore important to examine how such a significant crisis can affect the expression, frequency and progression of the disorder," she explains.

The children and young people who in the questionnaire had described thoughts and anxiety over how something serious could happen, e.g. that they themselves could become ill or lose family members, experienced the most significant worsening of their OCD symptoms. In particular, children who had begun suffering from OCD at an early age experienced the most pronounced worsening.

"For children who are already anxious about loss, the daily descriptions in the media of illness and death and recommendations about isolation and focus on infection can exacerbate these anxious thoughts, perhaps also especially for the youngest children, who may have greater difficulty understanding the significance of the infection, but who are also very dependent on parents and grandparents and thus are most vulnerable to loss," says Judith Nissen.

On the other hand, there is no correlation with anxiety about infection and impulsive hand washing. The study thus indicates that children and young people with OCD may be vulnerable in relation to a crisis such as COVID-19, where anxiety about something serious happening - including the loss of close relatives - characterises a particularly vulnerable group.

"This may be related to both the direct threat of the infection and to the consequences of having to maintain social distancing, social isolation and the significant level of focus on hygiene. The crisis is not over yet, and it's therefore very important that we continue to focus on vulnerable children and young people in the future," says Judith Nissen.

DALLAS, Nov. 9, 2020 -- Women veterans with posttraumatic stress disorder (PTSD), especially those who are younger and non-white, have an increased risk of developing heart disease, according to a study to be presented at the American Heart Association's Scientific Sessions 2020. The meeting will be held virtually, Friday, November 13 - Tuesday, November 17, 2020, and is a premier global exchange of the latest scientific advancements, research and evidence-based clinical practice updates in cardiovascular science for health care worldwide.

According to the National Institute of Mental Health, PTSD is a mental health condition that develops in some people who have experienced or witnessed a shocking, scary or dangerous event. "Previous research has linked PTSD to higher risks of ischemic heart disease, including heart attacks and heart pain or angina. However, most of those studies have been in men," according to study author Ramin Ebrahimi, M.D., professor of medicine at University of California Los Angeles and director of interventional cardiovascular research and co-director of the Cardiac Catheterization Laboratory at the Greater Los Angeles VA (Veterans Affairs) Medical Center.

"PTSD occurs twice as frequently in women as in men, and rates are particularly high among women veterans. Women veterans are the fastest growing group of patients within the VA health care system. And, despite being at high risk for many disorders including cardiovascular disorders, they have been understudied, underdiagnosed, undertreated and underrepresented in cardiovascular research," Ebrahimi said.

Ebrahimi and colleagues evaluated the medical records of women veterans cared for at all U.S. Veterans Health Administration centers between the start of 2000 and the end of 2017. They identified nearly 130,000 female veterans with PTSD and nearly 260,000 without the mental health condition. Women with a heart disease diagnosis before or within 90 days of the initial study-related visit were excluded from analysis. Records for annual exams, emergency room visits and other exams or hospitalizations were assessed for new diagnoses of coronary artery disease, angina or heart attacks.

Ebrahimi noted they found:

Women with PTSD had a 44% higher risk of developing ischemic heart disease compared to those without PTSD.

The increased risk was most prominent in younger women, especially those younger than 40 years old (72%).

The increased heart disease risk among women veterans with PTSD was also higher in racial and ethnic minorities, including Black women, non-white women from other racial backgrounds and women of Hispanic and Latina ethnicity, compared with white, female veterans.

"We were surprised by the magnitude of increased risk associated with PTSD in younger women, as current national guidelines do not recommend routine screening for cardiovascular disorders in women until the age of 45," Ebrahimi said. "Our results suggest that health care professionals should consider more routine and earlier screening for cardiovascular disorders in women with PTSD."

Researchers from the Complutense University of Madrid (UCM) and the NOVA University of Lisbon (UNL) have used platinum (Pt) compounds of a liquid crystalline nature to design nanocrystal structures capable of effectively encapsulating and transporting water-insoluble drugs that are otherwise difficult to administer.

The study, published in Nano Research, shows that besides their applications in bioimaging techniques as phosphorescent markers, the new Pt(II) nanocrystals may also have an application in biomedicine: to encapsulate water-insoluble drugs.

Such hydrophobic drugs include some anti-tumour therapies, which are difficult to administer because of their poor solubility in water, rendering it necessary to increase the dose in order to achieve the desired therapeutic effect, which also increases toxicity and side effects in the patient.

"In order to eliminate these problems, we strategically designed Pt(II) nanocrystals with ideal structural characteristics that make them excellent candidates for encapsulating and transporting water-insoluble substances", explained Mercedes Cano, the principal investigator of the MatMoPol Group in the Department of Inorganic Chemistry at the UCM.

Internal cavity isolated from water

Cristián Cuerva, who was a researcher in the Department of Inorganic Chemistry at the UCM when this area of research was launched and is now at the UNL, revealed that "the presence of extended alkyl chains oriented towards the exterior of the nanocrystals facilitates their stable dispersion in water", adding that "those located towards the interior favour the retention of hydrophobic substances within the internal cavity".

To carry out the study, the researchers prepared the new luminescent Pt(II) nanocrystals inside small spherical emulsions formed by mixing water with an oily solvent.

Subsequent evaporation of the solvent creates an internal cavity that is totally isolated from the aqueous medium and presents the ideal characteristics to encapsulate hydrophobic drugs.

The encapsulation assays were carried out using coumarin 6 (C6), a luminescent compound that is practically insoluble in water, as a hydrophobic substance model. Subsequent analysis revealed the presence of C6 inside the nanocrystals, achieving a high encapsulation efficiency of up to 79%.

From LCD to nanocapsules

One of the major revolutions in liquid crystals was their use in LCD screens on tablets, ebooks, laptops and digital watches, although they may now be displaced by OLED systems, which offer better performance.

"In recent decades, precisely when many people thought that liquid crystals had "reached the ceiling", we have found that these materials possess and enhance additional properties such as phosphorescence and conductivity, paving the way for new technological applications in the fields of luminescent sensors and electric batteries. By using nanoscience and nanotechnology, we have now demonstrated that liquid crystals could also be of great use in the field of biomedicine", concluded Cuerva.

A long-standing mystery in the study of glaciers was recently --- and serendipitously -- solved by a team led by University of Hawai'i at Mānoa astrobiologist and earth scientist Eric Gaidos. Their findings were published this week in the journal Geophysical Research Letters.

The mystery involves floods or "jokulhlaups" that emerge suddenly and unpredictably from glaciers or ice caps like those in Iceland where volcanic heat melts the ice and water accumulates in lakes underneath the glaciers. Scientists have long studied the development of these floods, which are some of the largest on Earth.

"These floods may affect the motion of some glaciers and are a significant hazard in Iceland," said Gaidos, professor at the UH Mānoa School of Ocean and Earth Science and Technology (SOEST). "But the mechanism and timing of the initiation of these floods has not been understood."

Then, in June 2015, an unexpected series of events revealed how these floods start.

That summer, Gaidos and colleagues drilled a hole to one of the Icelandic lakes to study its microbial life. While collecting samples through the borehole, the team noticed a downwards current, like a bathtub drain, in the hole.

"The flow was so strong we nearly lost our sensors and sampling equipment into the hole," said Gaidos. "We surmised that we had accidentally connected a water mass inside the glacier to the lake beneath. That water mass was rapidly draining into the lake."

A few days later, after the team had left the glacier, the lake drained in a flood. Fortunately, the flood was small and Icelanders have an elaborate early-warning system on their rivers so no people were hurt, nor infrastructure damaged in this event, Gaidos assured.

The researchers used a computer model of the draining of the flow through the hole , and its effect on the lake, to show that this could have triggered the flood.

"We discovered that the glacier can contain smaller bodies of water above the lakes fed by summer melting," said Gaidos. "If this water body is hydraulically connected to the lake then the pressure in the lake rises and that allows water to start draining out underneath the glacier."

While the team made an artificial connection to the lake in 2015, natural connections can form when water from rain or melting snow accumulates in crevasses and the pressure eventually forces a crack through the glacier to the lake. This discovery provides a new understanding of how these floods can start and how this depends on weather and the season.

Collaborators in Iceland are continuing to research this phenomenon using radio echo-sounding to search for water bodies within the ice, as well as study the larger lake below it.

Family Success

Using data from the HSE University longitudinal study Trajectories in Education and Careers (TrEC), Ilya Prakhov https://www.hse.ru/en/staff/prakhov, Olga Kotomina and Alexandra Sazhina determined which forms of family engagement in the school are useful and which are harmful to the student.

This study makes it possible to monitor students' entire educational path (for example, their complete secondary education plus university, or their first nine grades plus a college or technical school). The students surveyed for this study were in the ninth grade in 2012 and by 2015 were in universities and colleges or on the labour market. The TrEC contains data on the students' academic performance and their parents' SES (with cultural capital traditionally measured by the number of books in the family's home library).

In this study, the dependent variables were students' educational achievements, measured primarily as scores on the BSE and U.S.E., and their educational trajectories, while the constants were the different forms of parental engagement in their children's education (controlling for students' gender and the characteristics of their family and school).

The researchers identified four main factors that describe patterns of parental engagement. The first is parental control, such as checking that homework is completed and calling teachers about grades. The second factor is total engagement (the full spectrum of parental activity, from ensuring that homework is completed and hiring tutors to participating in school board meetings). The third factor is when parents are reasonably engaged by, for example, giving their children additional literature and attending parent-teacher meetings. The fourth factor is organizational: family members join the parents' committee and organize extracurricular events.

It turned out that when parents take an active part in school meetings, hire tutors and provide auxiliary literature to their children, the students score higher on the BSE and U.S.E. These forms of assistance increase the likelihood that children will finish out their high school education and go on to university. Membership in the parents' committee, however, has no effect.

As Ilya Prakhov explains, participation in such activities as school meetings lowers the risk of receiving inaccurate information. 'Being properly informed is an important element in choosing an educational trajectory and succeeding in it,' the researcher said. 'At parent-teacher meetings for upperclassmen, parents can receive information on the correct approach for taking the U.S.E., whether additional exam prep classes are available, possible cooperation between the school and universities, and Academic Olympics competitions.'

However, recruiting tutors and supplying additional literature does not help in every school subject. It has a positive correlation with U.S.E. results in Russian, but the connection for math is not as clear. Here, the type of school plays a significant role, with formal education trumping the role of tutoring.

Excessive Control

The new study shows that a family can also be overly engaged. The child needs 'a certain degree of independence in decision-making. This will favourably affect the incentives to study at school and choose a future path,' Mr Prakhov said.

A measured amount of family engagement -- as well as helping with, but not strictly controlling homework -- also has a positive correlation to students' educational success and whether they go on to study at university. On the other hand, the habit that, 'helicopter parents' have of 'hovering' over their children to check on homework and grades is definitely harmful and leads to lower U.S.E. scores. Excessive parental control has a particularly harmful influence on exam scores for ninth graders.

'Here, we are probably seeing the opposite effect: the child is studying poorly and so the parents are forced to take matters in hand,' the researcher said. 'However, exercising total control over a high school student's homework can cause them to protest or rebel, decreasing the motivation to improve academic performance. This can adversely affect U.S.E. results and, as a result, limit the choice of universities that will admit the student.'

Meanwhile, parental engagement depends on the type of family -- its educational level, income and cultural interests. As mentioned above, in families with a high SES, parents devote greater attention to their child's studies, but their engagement is more likely to be reasonable and measured. The type of high school also has a bearing on U.S.E. results, with those offering advanced courses and schools of higher status being the most effective.

Delayed Effect

The study also found that girls score higher on the BSE than boys do and family characteristics have a positive correlation to ninth-graders' final grades. At the same time, the type of school has little influence at this stage. In other words, the family -- in terms of both its characteristics and its level of engagement in the child's studies -- plays the greatest role in middle schoolers' academic performance.

It was also found that attending parent-teacher meetings, hiring tutors and supplying additional literature helps students entering high school grades 10 and 11. However, researchers also noted that a stable progression from the ninth to the eleventh grades was the most important factor behind the strong Russian and math scores on the U.S.E. that are so crucial to university admissions.

Thus, family support at the earlier stages of education can influence academic success in the final year of study, even if the nature of this influence has changed. In other words, a family's investment of time, effort and money in the child's education has a long-term positive effect.

Borrowing a page from high-energy physics and astronomy textbooks, a team of physicists and computer scientists at the U.S. Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) has successfully adapted and applied a common error-reduction technique to the field of quantum computing.

In the world of subatomic particles and giant particle detectors, and distant galaxies and giant telescopes, scientists have learned to live, and to work, with uncertainty. They are often trying to tease out ultra-rare particle interactions from a massive tangle of other particle interactions and background "noise" that can complicate their hunt, or trying to filter out the effects of atmospheric distortions and interstellar dust to improve the resolution of astronomical imaging.

Also, inherent problems with detectors, such as with their ability to record all particle interactions or to exactly measure particles' energies, can result in data getting misread by the electronics they are connected to, so scientists need to design complex filters, in the form of computer algorithms, to reduce the margin of error and return the most accurate results.

The problems of noise and physical defects, and the need for error-correction and error-mitigation algorithms, which reduce the frequency and severity of errors, are also common in the fledgling field of quantum computing, and a study published in the journal npj Quantum Information found that there appear to be some common solutions, too.

Ben Nachman, a Berkeley Lab physicist who is involved with particle physics experiments at CERN as a member of Berkeley Lab's ATLAS group, saw the quantum-computing connection while working on a particle physics calculation with Christian Bauer, a Berkeley Lab theoretical physicist who is a co-author of the study. ATLAS is one of the four giant particle detectors at CERN's Large Hadron Collider, the largest and most powerful particle collider in the world.

"At ATLAS, we often have to 'unfold,' or correct for detector effects," said Nachman, the study's lead author. "People have been developing this technique for years."

In experiments at the LHC, particles called protons collide at a rate of about 1 billion times per second. To cope with this incredibly busy, "noisy" environment and intrinsic problems related to the energy resolution and other factors associated with detectors, physicists use error-correcting "unfolding" techniques and other filters to winnow down this particle jumble to the most useful, accurate data.

"We realized that current quantum computers are very noisy, too," Nachman said, so finding a way to reduce this noise and minimize errors - error mitigation - is a key to advancing quantum computing. "One kind of error is related to the actual operations you do, and one relates to reading out the state of the quantum computer," he noted - that first kind is known as a gate error, and the latter is called a readout error.

The latest study focuses on a technique to reduce readout errors, called "iterative Bayesian unfolding" (IBU), which is familiar to the high-energy physics community. The study compares the effectiveness of this approach to other error-correction and mitigation techniques. The IBU method is based on Bayes' theorem, which provides a mathematical way to find the probability of an event occurring when there are other conditions related to this event that are already known.

Nachman noted that this technique can be applied to the quantum analog of classical computers, known as universal gate-based quantum computers.

In quantum computing, which relies on quantum bits, or qubits, to carry information, the fragile state known as quantum superposition is difficult to maintain and can decay over time, causing a qubit to display a zero instead of a one - this is a common example of a readout error.

Superposition provides that a quantum bit can represent a zero, a one, or both quantities at the same time. This enables unique computing capabilities not possible in conventional computing, which rely on bits representing either a one or a zero, but not both at once. Another source of readout error in quantum computers is simply a faulty measurement of a qubit's state due to the architecture of the computer.

In the study, researchers simulated a quantum computer to compare the performance of three different error-correction (or error-mitigation or unfolding) techniques. They found that the IBU method is more robust in a very noisy, error-prone environment, and slightly outperformed the other two in the presence of more common noise patterns. Its performance was compared to an error-correction method called Ignis that is part of a collection of open-source quantum-computing software development tools developed for IBM's quantum computers, and a very basic form of unfolding known as the matrix inversion method.

The researchers used the simulated quantum-computing environment to produce more than 1,000 pseudo-experiments, and they found that the results for the IBU method were the closest to predictions. The noise models used for this analysis were measured on a 20-qubit quantum computer called IBM Q Johannesburg.

"We took a very common technique from high-energy physics, and applied it to quantum computing, and it worked really well - as it should," Nachman said. There was a steep learning curve. "I had to learn all sorts of things about quantum computing to be sure I knew how to translate this and to implement it on a quantum computer."

He said he was also very fortunate to find collaborators for the study with expertise in quantum computing at Berkeley Lab, including Bert de Jong, who leads a DOE Office of Advanced Scientific Computing Research Quantum Algorithms Team and an Accelerated Research for Quantum Computing project in Berkeley Lab's Computational Research Division.

"It's exciting to see how the plethora of knowledge the high-energy physics community has developed to get the most out of noisy experiments can be used to get more out of noisy quantum computers," de Jong said.

The simulated and real quantum computers used in the study varied from five qubits to 20 qubits, and the technique should be scalable to larger systems, Nachman said. But the error-correction and error-mitigation techniques that the researchers tested will require more computing resources as the size of quantum computers increases, so Nachman said the team is focused on how to make the methods more manageable for quantum computers with larger qubit arrays.

Nachman, Bauer, and de Jong also participated in an earlier study that proposes a way to reduce gate errors, which is the other major source of quantum-computing errors. They believe that error correction and error mitigation in quantum computing may ultimately require a mix-and-match approach - using a combination of several techniques.

"It's an exciting time," Nachman said, as the field of quantum computing is still young and there is plenty of room for innovation. "People have at least gotten the message about these types of approaches, and there is still room for progress." He noted that quantum computing provided a "push to think about problems in a new way," adding, "It has opened up new science potential."

Bonfire Night celebrations contaminate our air with hugely elevated amounts of soot, scientists have found.

Researchers from the University of Leeds were monitoring air quality to determine whether soot created by fires and fireworks, known as black carbon, could help to create ice in clouds.

They found soot in the atmosphere around Guy Fawkes Night events was around 100 times its normal level.

Ice occurs naturally in clouds, but tiny particles of desert dust, soil dust, fungus and bacteria swept high into the air can cause supercooled water droplets in clouds to freeze around them. High concentrations of these ice-nucleating particles can cause clouds to freeze, potentially impacting the earth's climate.

The team carried out experiments on 5 November 2016 into the early hours of the following day, and in 2017 from November 4 and 5, filtering the air with samples taken hourly. Equipment was set up on the balcony of the School of Earth and Environment building, 15m from ground level and more than 0.5 km from any individual bonfires or firework displays, to give a representative view of the air quality across the city.

The filters were washed and the liquid subjected to different temperatures to replicate atmospheric conditions.

The researchers discovered black carbon produced on Bonfire Night did not act as ice nucleating particles - but they did not expect to see such high levels of the polluting matter in the atmosphere.

Black carbon particles are so small, they can penetrate deep into the lungs and cause irritation. Long term exposure can cause harmful effects on the heart and lungs and contributes to millions of deaths worldwide each year.

The paper, A major combustion aerosol event had a negligible impact on the atmospheric ice-nucleating particle population, has been published in Journal of Geophysical Research: Atmospheres today.

The research was funded by the European Research Council.

Lead author Michael Adams, Research Fellow in Atmospheric Ice Nucleation, said: "Our measurements showed that whilst pollution emitted on Bonfire Night shouldn't have any effect on whether clouds are liquid or ice, the elevated concentrations of soot and other pollutants in the atmosphere should be a warning to those with pre-existing health conditions, as the aerosol particles are in the size range where they can enter the lungs and cause problems."

Research supervisor Benjamin Murray, Professor of Atmospheric Science in Leeds' School of Earth and Environment, said: "Bonfire Night is a massive pollution event across the UK. People with existing health problems, such as heart and lung conditions, are at increased risk."

"The impact on clouds and climate was not clear. The good news is that Bonfire Night does not impact the formation of ice in supercooled cloud droplets. But, we know that BC causes climate warming in other ways.

"I was surprised to see levels of black carbon so persistently high for so long on multiple nights. It was striking how poor air quality was on Bonfire Night."

Weather conditions can affect how long the particles remain in the air. The team found the pollution was flushed out of the city within a few hours during the 2016 experiment, due to a brisk wind from the north.

But in 2017 the air was relatively still and the pollution lingered into the next day.

While providing insight into the levels of black carbon emitted on Bonfire Night, the team's discoveries have also contributed to the understanding of different sources of ice nucleating particles - a key research area in climate science.

Prof Murray said: "Clouds containing supercooled water and ice are first order importance for climate. Vast cloud systems made of a mixture of ice and water over the world's oceans buffer the warming effect of CO2.

"But the buffering capacity depends on how much ice is in them, which in turn depends on the concentration and distribution of ice nucleating particles.

"We found that aerosol particles emitted during the celebration are not as effective at nucleating ice as aerosol particle already present in the atmosphere.

"We conclude that aerosol particles emitted from combustion processes such as those observed on Bonfire Night are not an important source of ice nucleating particles."

Metal pollution from historic mining appears to be weakening scallop shells and threatening marine ecosystems in an area off the coast of the Isle of Man, a major new study suggests.

The research, led by an interdisciplinary team at the University of York, suggests that the contamination of seabed sediments with zinc, lead and copper from the mining of these metals, which peaked on the island in the late 19th century, is causing the shells of king scallops to become significantly more brittle.

The thinning and weakening of shells threatens the species by leaving them more exposed to the crushing claws of crabs and lobsters, and, in turn, threatens the marine ecosystem because of the important functions, such as water filtration, that molluscs like scallops carry out.

Given that metal contamination is common in many coastal areas around the world, the researchers are concerned that other species of marine mollusc like mussels, oysters and clams, which together provide more than a quarter of the world's seafood, may be similarly affected.

The current consensus on acceptable levels of metal pollution should be revised, the researchers say, as evidence of damage to scallop shells was present even in areas with metal contamination levels currently not thought to cause significant damage to the marine environment.

Lead author of the study, Dr Bryce Stewart from the Department of Environment and Geography at the University of York, said: "The fact that comparably low levels of heavy metal contaminations appear to affect shell structure and strength in such a potent way represents a challenge to marine species management and conservation strategies. This is particularly true given that the effects we observed are likely to be amplified in the future by ongoing human activities and climate change.

"The potential long-term impact of anthropogenic metal pollution on marine organisms, as shown in our work, is remarkable since the last major mine on the Isle of Man closed in 1908."

Over a period of over 13 years, the researchers compared scallops collected from six areas of the Irish Sea around the Isle of Man. Most scallops exhibited perfectly normal shell growth and strength. However, in one area off Laxey - known to be contaminated with metal pollution, the shells were significantly weaker.

Structural analysis of shells by physicists at the University of York revealed that Laxey scallops had significantly weaker shells and a disrupted shell structure. Lethal damage rates in scallop catches from Laxey were twice as high as those at uncontaminated areas.

Joint corresponding author Professor Roland Kröger, from the Department of Physics at the University of York, said: "We analysed the shell structure of the scallops with cutting-edge microscopy techniques and discovered that shells from Laxey were thinner and exhibited a pronounced mineralisation disruption parallel to the shell surface within the central region of both the top and bottom valves.

"Our data suggest that these disruptions caused reduced fracture strength and therefore could increase mortality.

"It is not clear exactly how metal bearing sediments may be affecting the shell formation process. Metals could be incorporated into shells replacing calcium during the biomineralization process or they may modify the activity of proteins during the crystallisation process and disrupt shell growth."

The researchers looked at a wide range of alternative explanations for the impact on scallop shells but found no other environmental factors that could explain their results.

Dr Stewart added: "While the scallops are still perfectly safe to eat, we believe our results provide a compelling case that metal contamination is playing an important role in the development of thinner and weaker shells at Laxey, and therefore the observed high damage rates.

"The shell characteristics of bivalve molluscs such as clams, oysters, mussels and scallops could potentially function as a good bellwether for the scientific community in assessments of how pollutants are affecting biological organisms."

With 2020 hijacked by COVID-19, a team of QUT researchers in Brisbane, Australia, say social media analytics can capture the attitudes and perceptions of the public during a pandemic. They also suggest social media is now the best way to encourage people to follow measures and restrictions.

Led by Associate Professor Tan Yigitcanlar from QUT's School of Built Environment, and in collaboration with researchers in Afghanistan, Iran and Italy, the researchers collected 96,666 geotagged tweets originating from Australia between 1 January and 4 May 2020, and analysed 35,969 of them after data cleaning to remove automated messages, irrelevant messages and web links.

The resultant paper - How can social media analytics assist authorities in pandemic-related policy decisions? Insights from Australian states and territories - has been published by Springer journal Health Information Science and Systems.

"From the Plague of Athens in 430 B.C., to the Black Death of the 1300s, through to the Spanish Flu of 1918-1920 and the Swine Flu outbreak in 2009, pandemics are not new. However, increased globalisation since the 1980s has accelerated their spread, as we have seen this year with COVID-19," said Professor Yigitcanlar.

"What started late last year in Wuhan, China was declared a pandemic by the World Health Organization in March. Global cases are heading towards 50 million and there have been more than 1.2 million deaths so far.

"The pandemic has led to many countries introducing lockdowns and limited citizen movements. These restrictions in turn have triggered an increased use of digital technologies and platforms by the public.

"Our aim was to generate insights into how social media analytics can assist authorities in pandemic-related policy decisions.

"We chose Australia as our case study because it has been highly successful in flattening the curve and social media analytics are increasingly used by the health sector here.

"Australia is also an advanced nation with a diverse culture that adapts the technological trends of the world, with the largest being social media. In 2018, 79 per cent of Australians used social media."

Professor Yigitcanlar said the study concluded social media analytics are a valuable tool in understanding the thoughts and actions of the public during a pandemic. Co-author and QUT PhD student Nayomi Kankanamge added that crowdsourced social media data could guide interventions and decisions of authorities during a pandemic.

"We also found that effective use of government social media channels, such as Twitter or Facebook, can help enhance public health education and awareness concerning social distancing restrictions and other measures or restrictions such as the latest lockdown in the UK and much of Europe. This is the best way to reach people in the 21st century", she said.

"In this digital age, local community perceptions and suggestions about social distancing policies, self-isolation, quarantines, movement control, travel restrictions, lockdowns and other changes are well reflected through social media messages.

"A thorough analysis of such social media data helps us understand the community demands, issues, and reflections."

Associate Professor Yigitcanlar said the researchers chose Twitter because it has become the fastest growing social media platform source in the world. It also offers an Application Programming Interface (API) to researchers and practitioners to conduct analysis.

"Social media analytics can help assist policy- and decision-makers to review community perceptions about COVID-19, and to identify the key requirements of the community to cope with the pandemic situation", he said.

"Our analysis has shown that the Australian public was not happy at the early stage of the pandemic curve as they seemed to believe that the Australian government was not responding appropriately.

"As such, people were in a panic mode, and tried to prepare to face the pandemic at their capacity. The words, 'toilet/paper' were very common in Twitter in all states/territories during this stage. This was because consumer panic buying patterns took place in Australia, where people tried to stock toilet paper, hand sanitisers, food, and other commodities. This indicated how Australian people act when the government does not provide confidence.

"From February 2020 onwards, the Australian government started to add travel restrictions to combat COVID-19 which built trust. Popular words like 'testing' and 'shutdown' among positively classified tweets showed people were generally happy about the actions taken by the government to combat the virus dispersion in Australia.

"For instance, the tweets circulated in Queensland emphasised the significance of expanding the number of testing per day at the early stage to stop spreading the virus rapidly. Most of the tweets discussed the importance of wearing masks."

The Falkland Islands are a South Atlantic refuge for some of the world's most important seabird species, including five species of penguins, Great Shearwaters, and White-chinned Petrels. In recent years, their breeding grounds in the coastal tussac (Poa flabellata) grasslands have come under increasing pressure from sheep grazing and erosion. And unlike other regions of the globe, there has been no long-term monitoring of the responses of these burrowing and ground nesting seabirds to climate change.

A 14,000-year paleoecological reconstruction of the sub-Antarctic islands done by an international research team led by The University of Maine (UMaine) including Dr Moriaki YASUHARA from the School of Biological Sciences and The Swire Institute of Marine Science, The University of Hong Kong (HKU), has found that seabird establishment occurred during a period of regional cooling 5,000 years ago. Their populations, in turn, shifted the Falkland Island ecosystem through the deposit of high concentrations of guano that helped nourish tussac, produce peat and increase the incidence of fire. The findings were recently published in the journal Science Advances.

Nutrient inputs from seabirds

"This terrestrial-marine link is critical to the islands' grasslands conservation efforts going forward," says Dulcinea GROFF, who led the research as a PhD student in UMaine. "The connection of nutrients originating in the marine ecosystem that are transferred to the terrestrial ecosystem enrich the islands' nutrient-poor soil, thereby making the Falkland Islands sensitive to changes in climate and land use.

"Our work emphasizes just how important the nutrients in seabird poop are for the ongoing efforts to restore and conserve their grassland habitats. It also raises the question about where seabirds will go as the climate continues to warm," said Groff, who conducted the research in the Falkland Islands during expeditions in 2014 and 2016 led by Jacquelyn GILL, an Associate Professor of paleoecology and plant ecology in the UMaine Climate Change Institute.

The UMaine expedition team collected a 476-centimeter peat column from Surf Bay, East Falkland. The 14,000-year record revealed in the undecomposed tussac leaves of the peat column captures the development of a terrestrial-marine linkage that supports some of the most important breeding colonies of seabirds in the Southern Ocean today.

The absence of seabirds at the East Falklands site prior to 5,000 years ago suggests that seabirds may be sensitive to warmer mediated sea surface temperatures, which can impact their food supply, according to the research team. With a warming South Atlantic today, the question is whether the Falkland Islands, about 300 miles east of South America, will continue to be a seabird breeding "hot spot". The research team suggests that as the Southern Ocean continues to warm in the coming decades, the Falkland Islands seabird communities may undergo abrupt turnover or collapse, which could happen on the order of decades.

The 14,000-year record from East Falkland revealed that for 9,000 years before the arrival of seabirds, the region was dominated by low levels of grasses, a heathland of ferns and dwarf Ericaceous shrubs. About 5,000 years ago, the researchers says, an "abrupt transition" appears to occur. Concentrations in bio-elements such as phosphorus and zinc increase. Grass pollen accumulation rates skyrocket, indicating the establishment of tussac grasslands within 200 years of the establishment of seabird colonies on the island. Also found in the core: increased accumulation rates of peat and charcoal. "This timing is consistent with that of the Southern Ocean cooling that known paleoclimatic records consistently indicate.", said Yasuhara, a paleoecologist and paleoclimatologist in HKU, who is familiar with polar paleoclimatology and paleoceanography.

It is clear that the addition of seabird populations bringing nutrients from the marine environment to the island drove changes in the terrestrial plant community structure, composition and function, as well as increased fire activity and nutrient cycling. What remains unclear is what drove the abrupt ecosystem shift, including the impacts of climate change and extinction, and the geographical distribution of living things through space and time.

"Our study is also a powerful reminder of why we need to understand how different ecosystems are connected as the world warms," says Gill. "Such understanding is especially important in polar regions and ecosystems that are known to be sensitive to climate change," continues Yasuhara. Gill concluded, "We know that many seabirds in the South Atlantic rely on these unique coastal grasslands, but it turns out that the grasses also depend on the nutrients seabirds provide. Because they rely on ecosystems in the ocean and on land for their survival, seabirds are really excellent sentinels of global change. We just don't have good long-term monitoring data for most of these species, so we don't know enough about how sensitive they are to climate change. The fossil record can help us fill in the gaps."

Tokyo, Japan - Researchers from the Institute of Industrial Science, the University of Tokyo (UTokyo-IIS) have designed novel linear nanomotors that can be moved in controlled directions using light. This work opens the way for new microfluidics, including lab-on-a-chip systems with optically actuated pumps and valves.

The world of nanoscale machines looks very different to the one containing the contraptions to which we have become accustomed. For example, powering and precisely controlling a motor smaller than a single bacterium can be much more difficult than, say, driving a car.

Now, a team of scientists led by UTokyo-IIS have introduced a system of linear motors made from gold nanorods that can move in a controlled direction when exposed to laser light. Like a sailboat that can move in any desired direction by adjusting the rigging, these nanomotors are not constrained to follow the direction of the light. Rather, they move based on their orientation even when exposed to a laser beam traveling from another angle.

The motion is powered by the lateral optical force created from the sideways scattering of light from the particles. As a result, the need to focus or shape the laser beam with lenses, which was once a difficult task, is eliminated. In addition, motor sizes are not constrained by the wavelength of light, unlike with previous devices.

"Instead of being limited to moving in the direction of laser light or the field gradient, the direction is determined by the orientation of the nanoparticles themselves," first author Yoshito Tanaka says. The key to this technology is the localized surface plasmon resonance--collective oscillations of free electrons--within periodic arrays of nanorods. These can produce scattered light in a particular direction. "Careful design of the separation between nanorods leads to constructive interference in one direction and destructive interference in the other. This allows us to produce directional scattering to propel the nanomotor," senior author Tsutomu Shimura says.

The researchers envision using this technology to create a new platform for nano-sized machinery with moving parts that follow predetermined paths while being nudged along by unfocused light. This will greatly reduce the cost and complexity of these devices while also improving precision and reliability.

The membranes surrounding our brains are in a never-ending battle against deadly infections, as germs constantly try to elude watchful immune cells and sneak past a special protective barrier called the meninges. In a study involving mice and human autopsy tissue, researchers at the National Institutes of Health and Cambridge University have shown that some of these immune cells are trained to fight these infections by first spending time in the gut.

"This finding opens a new area of neuroimmunology, showing that gut-educated antibody-producing cells inhabit and defend regions that surround the central nervous system," said Dorian McGavern, Ph.D., senior investigator at NINDS and co-senior author of the study, which was published in Nature.

The central nervous system (CNS) is protected from pathogens both by a three-membrane barrier called the meninges and by immune cells within those membranes. The CNS is also walled off from the rest of the body by specialized blood vessels that are tightly sealed by the blood brain barrier. This is not the case, however, in the dura mater, the outermost layer of the meninges. Blood vessels in this compartment are not sealed, and large venous structures, referred to as the sinuses, carry slow moving blood back to the heart. The combination of slow blood flow and proximity to the brain requires strong immune protection to stop potential infections in their tracks.

"The immune system has invested heavily in the dura mater," said Dr. McGavern. "The venous sinuses within the dura act like drainage bins, and, consequently, are a place where pathogens can accumulate and potentially enter the brain. It makes sense that the immune system would set up camp in this vulnerable area."

In this study, Dr. McGavern's team worked with researchers in a lab led by Menna R. Clatworthy, M.D., Ph.D., University of Cambridge, UK to look at what immune cell types reside in the outer layers of the meninges of mice and humans. What they discovered was rather surprising: there were many immune cells previously educated to make antibodies against specific microbes. These antibody-producing cells, called IgA cells, are typically found in other barriers such as the mucous membranes of the bronchial tree of the lungs and gut.

"This finding was completely unexpected," said Dr. McGavern. "Prior to our study, IgA cells had not been shown to reside in the dura mater under steady state conditions."

When compared to normal control mice, researchers observed that germ-free mice, which do not have their own microbiome, had almost no IgA cells in their meninges. They then reconstituted the gut of these mice with microbes that could not move elsewhere and demonstrated that the network of meningeal IgA cells was fully restored. This did not occur when the skin of germ-free mice was reconstituted with different microbes, suggesting that bacteria in the gut were important in educating meningeal IgA cells.

The next step was to further confirm the gut origin of cells in the meninges by looking at the IgA DNA sequences. There are likely millions of different sequences of IgA throughout the body ready to detect a wide range of threats. When two of these sequences match, it suggests that the two cells being compared originated from the same source.

When the researchers compared DNA sequences from IgA cells found in the meninges to those taken from a very short segment of the intestine, they found a more than 20 percent overlap between the two--much greater than would be possible through random chance.

"It's truly remarkable that in such a small piece of intestine we would see this large an overlap with cells in the meninges," said Dr. McGavern. "These data provide more compelling evidence that the brain is protected by immune cells that are educated in the gut."

As in the brain, the lining of the gut is sealed to prevent leakage of its contents into the body. When the lining of the gut is breached, significant inflammation and activation of the immune system occurs. When the researchers intentionally breached the gut in this study, they saw a significant response in the meninges to defend against the presence of microbes in the blood.

The researchers also looked at the role IgA cells play in protecting the brain against known infections by injecting a fluorescent version of a fungus that, under normal conditions, leads to a strong response of IgA cells in the meninges that traps the fungus similarly to bacteria. However, in mice that no longer had IgA cells either due to genetic manipulation or the application of a depleting drug to the skull (so that only meningeal IgA cells were affected), the fungus found its way into brain tissue, which had fatal consequences in all of the treated mice.

"By simply removing the IgA cells from the meninges, and without affecting any other immune cells, this fungus went from being a controlled pathogen to causing a fatal brain infection," said Dr. McGavern. "This clearly shows the importance of the local immune response."

Dr. McGavern continued by explaining that the antibody-secreting cells in these sinuses do not wait for infection to become active, but rather they constantly pump out antibodies in anticipation of foreign pathogens. This "always on" process is another means by which this highly sensitive region is protected by the immune system.

When mice were treated with antibiotics, there was a decrease in the number of IgA cells in the meninges, suggesting that depleting microbes in the body, even for a short period of time, decreases the ability of the immune system to respond to infection. Likewise, changes in the microbiome--for example, due to a change in regional diet--would be expected to affect the composition of IgA cells as the system continuously adapts.

Future work in the McGavern lab will focus on mechanisms that allow for continual education and re-education of IgA cells in the meninges.

Kanazawa, Japan - Researchers at Kanazawa University monitored the emission of blue-green light from water-soluble tetraphenylethene molecules adsorbed at a phospholipid-adsorbed liquid-liquid interface made to resemble a biomembrane. They found that the process could be reversibly controlled by an externally applied potential (voltage), which opens the possibility for a new class of molecular probes and targeted drug delivery systems.

The targeted delivery of therapeutic drugs or DNA directly to cells has many uses for treating disease, hence there is increasing interest in biomolecules that interact directly with cell membranes. Aggregation-induced emission (AIE), a promising technique with applications for functional materials, optoelectronics, and biomedical engineering, is a process by which self-aggregates can be made fluorescent upon stacking together. Tetraphenylethene (TPE) derivatives are propeller-shaped molecules with four phenyl rings which exhibit this property. Individually, these molecules are non-fluorescent, because their photo-excited states decay to the ground state through non-emissive molecular vibration or rotation. However, when several of these molecules aggregate together, they become fluorescent and emit blue-green light.

Researchers from the Institute of Science and Engineering at Kanazawa University studied the AIE behavior of water-soluble TPE derivatives on an artificial cell membrane surface that was formed by self-assembly of phospholipid molecules, which each have a hydrophilic (water-loving) "head" and two hydrophobic (water-fearing) "tails". Phospholipids can also be used to make bubbles called vesicles that can fuse with living cell membranes to deliver a drug or DNA payload. "Potential applications of this work include the selective labeling of targeted vesicles containing pharmaceutical drugs," says senior author of the study Hirohisa Nagatani. Using ion transfer voltammetry and surface-sensitive modulation spectroscopy, the research team was able to show that the phase transfer and interfacial adsorption of charged TPE molecules occurred reversibly based on an applied potential. This mimics the membrane potential of the living cells, which plays a crucial role in many physiological processes, including ion transportation and nerve impulse transmission. "The voltage-induced behavior we observed in simple water-soluble molecules may be important for the development of new sensitive probes of membrane potential for biomedical applications," explains Nagatani. "Our system could also be an alternative to voltage-sensitive dyes as molecular probes". The researchers also note the possibility of using this system as a photosensitizer for cancer phototherapy, in which cells can be selectively marked for light radiation.