Culture

Want to smooth out your wrinkles, erase scars and sunspots, and look years younger? Millions of Americans a year turn to lasers and prescription drugs to rejuvenate their skin, but exactly how that rejuvenation works has never been fully explained. Now, Johns Hopkins researchers have discovered that laser treatments and the drug retinoic acid share a common molecular pathway. Moreover, that pathway -- which lets skin cells sense loose RNA molecules -- is also turned up in mice when they regenerate hair follicles. Results are described in the June 26 issue of Nature Communications.

"Understanding the biology behind how cellular damage can lead to this type of regeneration can harness a new generation of therapeutics," says Luis Garza, M.D., Ph.D., associate professor of dermatology at the Johns Hopkins University School of Medicine.

Researchers have known for decades that mice -- unlike humans -- can regenerate hair follicles after a deep wound. Recent studies by Garza and others found that loose pieces of RNA, called self-noncoding double-stranded RNA (dsRNA) can spur this regeneration. They hypothesize that this may be because dsRNA is released by damaged cells at the site of a wound. Garza and his colleagues were curious whether dsRNA also played a role in skin rejuvenation treatments such as laser therapy, microneedling and facial abrasion, which all involve temporary damage to skin cells. Although these treatments are well-established among dermatologists, researchers haven't been clear why they work.

The team collected biopsies from 17 patients being treated at The Johns Hopkins Hospital with conventional laser skin rejuvenation to electively erase sunspots and wrinkles. All patients were Caucasian women with an average age of 55, and treatments were performed on their faces and arms. Skin biopsies were collected before the laser treatment and one week after the procedure.

Garza and his colleagues analyzed the expression levels of genes in each sample and discovered that genes involved in sensing dsRNA as well as genes involved in producing the skin's natural retinoic acid were all expressed at higher levels after the laser treatment. Next, the researchers treated isolated human skin cells with loose dsRNA -- mimicking the effect of the laser treatment. The amount of retinoic acid inside the cells increased by more than tenfold. Commercially produced retinoic acid is already used to treat acne, wrinkles and sunspots.

"It's not an accident that laser rejuvenation and retinoic acid have both been successful treatments for premature aging of the skin from sun damage and other forms of exposure," says Garza. "They're actually working in the same molecular pathways and nobody knew that until now."

To further strengthen and understand the connection, the researchers turned back to mice. They knew that in both mice and humans, a protein called toll-like receptor 3 (TLR3) senses dsRNA. When Garza's group engineered mice to lack TLR3, the animals could no longer regenerate hair follicles after a wound. But when the researchers gave these mice retinoic acid, they regained the ability to regenerate the follicles. The results point toward a pathway involving TLR3 that senses double-stranded RNA and turns up the synthesis of retinoic acid.

"In retrospect, it makes a lot of sense because retinoic acid is already a mainstay of wrinkle reduction and nobody knew what turned it on," says Garza. "Now we know that damage leads to dsRNA, which leads to TLR3 activation and retinoic acid synthesis."

The findings could lead to novel strategies to reduce wrinkles and sunspots by combining retinoic acid and laser treatments in new ways, Garza says. And they could also lead to ways to regenerate hair follicles, as mice do when there's an increase in dsRNA after a wound.

"After a burn, humans don't regenerate structures like hair follicles and sweat glands that used to be there," says Garza. "It's possible in light of these new findings that double-stranded RNA may be able to improve the appearance of burn scars."

Against a backdrop of long-term rises in temperature in recent decades, California has seen ever higher spikes in seasonal wildfires, and, in the last two years, a string of disastrous, record-setting blazes. This has led scientists, politicians and media to ponder: what role might warming climate be playing here? A new study combs through the many factors that can promote wildfire, and concludes that in many, though not all, cases, warming climate is the decisive driver. The study finds in particular that the huge summer forest fires that have raked the North Coast and Sierra Nevada regions recently have a strong connection to arid ground conditions brought on by increasing heat. It suggests that wildfires could grow exponentially in the next 40 years, as temperatures continue to rise.

The study notes that average summer temperatures in the state have risen 3.25 degrees Fahrenheit since 1896, with three-quarters of that increase occurring since the early 1970s. From 1972 to 2018, the area burned annually has shot up fivefold, fueled mainly by a more than eightfold spike in summer forest fires. The researchers say the summer forest-fire increases are driven by a simple mechanism: when air heats up even modestly, it causes more moisture to evaporate from soils and vegetation. The result: fires start more easily, and can spread faster and farther. During the fall, and in non-forested areas, different dynamics may be at work and the results are less clear; but the researchers project that climate-driven aridity is likely to play a growing role there as well.

"It's not a surprise to see that climate has this effect in forests, but California is so big and so variable, there is no one-size-fits-all explanation for how climate might affect wildfires across the board," said the study's lead author, Park Williams, a bioclimatologist at Columbia University's Lamont-Doherty Earth Observatory. "We have tried to provide one-stop shopping to show people how climate has or, in some cases, hasn't affected fire activity." Williams and his colleagues have already shown in a 2016 study that heightened temperatures and resulting aridity on the ground has doubled the area burned in forest fires over wider areas of the U.S. West in past decades. The new study appears in the journal Earth's Future.

The premise that warmer air draws moisture from the ground level -- a phenomenon known as vapor pressure deficit -- is already well established. However, many confounding factors can shift fire risk up or down, and so it is not always possible to measure the effects of vapor pressure deficit. In California, human infrastructure is sprawling into forests, introducing more chances for people to both cause fires and suffer from them. And a century of efforts to suppress virtually all fires has led to a buildup of flammable materials in many forests. On the other hand, fragmentation of forest landscapes by human intrusion may in some cases limit the spread of fires. Rainfall and snow can vary year to year, sometimes adding to fire risk, sometimes subtracting. And areas dominated by shrubs or grasses instead of trees may not react the same way.

The researchers combined data from many sources, some of it going back more than 100 years. They found that growing temperature-induced vapor pressure deficit accounted for nearly all the growth in forest fires from 1972-2018. In 2017, a modern state record was set for the largest individual wildfire (more than 285,000 acres) and the most destructive (5,636 structures burned, 22 people killed). 2018 saw a new record for total annual area burned (almost 1.7 million acres), and the 2017 records were broken for the biggest individual fire (the Mendocino Complex fire, which took out 464,500 acres) and the most destructive: the Camp Fire, which burned 18,804 structures and killed 85 people. The Camp Fire leveled almost the entire forest community of Paradise.

"The ability of dry fuels to promote large fires is non-linear, which has allowed warming to become increasingly impactful," says the study. "Human-caused warming has already significantly enhanced wildfire activity in California, particularly in the forests of the Sierra Nevada and the North Coast, and will likely continue to do so in the coming decades."

That said, the authors note that the effects of climate are highly seasonal, and can vary depending on vegetation type, topography and human settlement patterns across California's highly diverse landscape. In summer, they found that summer fires did not increase in many non-forested areas dominated by grasses or shrubs. This, they say, was probably due to a combination of intense firefighting and prevention efforts, and reduced vegetation due to drought. In fall, destructive fires have grown, but because the dynamics of this season are complex, the effects of warming climate are not as obvious -- at least not yet. The researchers say fall fires are driven in large part by powerful winds sweeping from the highland interior, as well as the amount and timing of precipitation, which tends to pick up around this time of year. These factors wax and wane from year to year, perhaps masking the effect of overall warming. But that effect is indeed just starting to show up in fall, and is likely to become more evident in the future, says Williams.

What happens at the molecular level when plants defend against invading pathogens? Previously it was assumed that the processes were roughly the same in all plants. However, this is not true, as a team of biologists from Martin Luther University Halle-Wittenberg (MLU) has demonstrated in a new study published in the scientific journal The Plant Cell. The researchers investigated defence processes in the wild tobacco plant N. benthamiana and found that the processes work quite differently than previously thought. The team also describes in the study how they discovered this complex interaction with the aid of CRISPR/Cas9 genome editing techniques.

When warding off pathogens, plants only have their innate immune systems to fall back on. "A plant's immune system is rather simple. Special receptor proteins on the surface of the plant cells can recognize pathogens and fight them off. This induces a low-level immune response," says Dr Johannes Stuttmann from the Institute of Biology at MLU. However, some bacteria have found a way to overcome this defence mechanism: They inject so-called effector proteins directly into the plant cell to suppress defence reactions. Over the course of evolution, plants have adapted to this trick and have developed other receptor proteins. These proteins recognise the invaders inside the cell via the effector proteins, and rapidly trigger a strong immune reaction. "Since plants do not have their own immune cells or antibodies, the intracellular receptor proteins play a key role in the plant's immune response," explains Stuttmann.

So far, the fundamental principles of plant immune systems have primarily been studied in thale cress (Arabidopsis thaliana), a relatively simple model organism. Stuttmann's group now wanted to find out whether these findings could also be transferred to the tobacco plant N. benthamiana. According to Stuttmann, its genome is considerably more complex and has yet to be completely sequenced. However, the plant has several advantages that make it interesting for further research.

The team investigated a special class of receptors inside the cell called TNL receptors. This class of immune receptors is known to only function properly in conjunction with a specific protein complex. In order to see whether the same genes are responsible for the immune systems of the two plant species, the researchers first knocked-out several candidate genes in tobacco using genome editing techniques and then swapped genes between the two species. They then tested whether the plants still reacted to pests. "An unexpected complexity was discovered: While a TNL receptor in the tobacco plant also worked in thale cress, this did not apply to the genes of the protein complex. In fact, tobacco plants require a different protein complex than thale cress for a TNL-receptor-induced immune response. The signalling pathways for immune reactions in different plants appear to vary," says Stuttmann. This is surprising because it was previously assumed that these processes were largely identical in plants, since the proteins involved have changed relatively little in the course of plant evolution.

"The widespread notion that findings from Arabidopsis thaliana can easily be transferred to other species often proves false," concludes Stuttmann. At the same time, the new study serves to establish N. benthamiana as a model organism for these and other questions.

The researchers want to use similar genetic patterns, which have been present in the blood of humans and animals for thousands of years, to improve computer-assisted disease prognosis.

The research project is unusual for bioinformaticians not only because of the cooperation with the zoo. "Measuring the molecular blood profiles of animals has never been done before in this way," explains Andreas Keller, bioinformatics professor at Saarland University. Instead of examining tissue and data from human patients, Keller and Eckart Meese, a human geneticist from Saarbrücken, analyzed blood samples from 21 animals. Zoo director Richard Francke had collected the blood during routine examinations between 2016 and 2018 and made it available to the scientists. In fact, these scientists normally investigate biomarkers that occur in human blood in order to identify lung tumors or diseases such as Alzheimer's and Parkinson's earlier and better. "Micro-RNAs are well suited for this," says Andreas Keller.

"These are short sections of specific molecules in ribonucleic acid that play an important role in the control of genes. In order to find these sections, the researchers use modern bioinformatic methods, including machine learning, a method of artificial intelligence. This in turn leads to a challenge in which the animals from the two Saarland zoos can help. "Up to 20 million data points are collected per (human) patient. The machine learning methods recognize the typical patterns, for example for a lung tumor or Alzheimer's disease. However, it is difficult for artificial intelligence to learn which biomarker patterns are real and which only seem to fit the respective clinical picture." This is where the blood samples of the animals come into play.

"If a biomarker is evolutionarily conserved, i.e. also occurs in other species in similar form and function, it is much more likely that it is a resilient biomarker," explains Professor Keller. For this reason, the researchers analyzed the residues from the blood samples taken from the animals. A total of 21 samples were taken from 19 animal species, including a coati and a Humboldt penguin. "The new findings are now being incorporated into our computer models and will help us to identify the correct biomarkers even more precisely in the future," explains Keller.

The researchers from Saarbrücken have published their results in the renowned journal Nucleic Acids Research. In addition, they have set up a database in which they also enter their current results. So far, scientists have examined the blood of a total of 40 animals, including an anaconda and a kangaroo. Scientists from all over the world now have access to this data. The research project was financially supported by the state government of Saarland.

At present, niobium is the material of choice for constructing superconducting radio-frequency cavity resonators. These will be used in projects at the HZB such as bERLinPro and BESSY-VSR, but also for free-electron lasers such as the XFEL and LCLS-II. However, a coating of niobium-tin (Nb3Sn) could lead to considerable improvements.

Superconducting radio-frequency cavity resonators made of niobium must be operated at 2 Kelvin (-271 degrees Celsius), which requires expensive and complicated cryogenic engineering. In contrast, a coating of Nb3Sn might make it possible to operate resonators at 4 Kelvin instead of 2 Kelvin and possibly withstand higher electromagnetic fields without the superconductivity collapsing. In the future, this could save millions of euros in construction and electricity costs for large accelerators, as the cost of cooling would be substantially lower.

A team led by Prof. Jens Knobloch, who heads the SRF Institute at HZB, has now carried out tests of superconducting samples coated with Nb3Sn by Cornell University, USA, in collaboration with colleagues from the USA, Canada, and Switzerland. The experiments took place at the Paul Scherrer Institute, Switzerland, at TRIUMF, Canada, and the HZB.

"We measured the critical magnetic field strengths of superconducting Nb3Sn samples in both static and radio-frequency fields", says Sebastian Keckert, first author of the study, who is doing his doctorate as part of the Knobloch team. By combining different measurement methods, they were able to confirm the theoretical prediction that the critical magnetic field of Nb3Sn in radio-frequency fields is higher than that for static magnetic fields. However, the coated material should display a very much higher critical magnetic field level in a radio-frequency field. Thus, the tests have also shown that the coating process used currently for the production of Nb3Sn might be improved upon in order to more closely approach the theoretical values.

If they don't receive antiretroviral therapy (ART), most HIV patients see a progressive weakening of their immune system. But a very small percentage of patients--0.3%--spontaneously control the virus themselves, without ART. Could an explanation lay partly in the sets of genes expressed by scarce white blood cells that recognize HIV? Yes, according to a study published in Nature Immunology and conducted by researchers at the University of Montreal Hospital Research Centre (CRCHUM).

Critical for the coordination of immune responses, CD4 T cells are important white blood cells (lymphocytes) that help control chronic infections like HIV. But on average only about one cell in 1,000 in the CD4 T cell population can recognize the virus.

"With my research team and my collaborators, we comprehensively determined the entire set of genes expressed by these rare cells from the blood of people chronically infected with HIV in whom the virus was abundant prior to ART," said Daniel Kaufmann, a CRCHUM researcher and an infectious disease specialist. "We then compared it to the cells of HIV controllers, infected people who control the virus in the absence of therapy. This type of powerful approach, also called genome-wide transcriptional profiling, measures the activity of thousands of genes at once, thus creating a global picture of cellular function."

Using sophisticated cell analysis techniques, lead author Antigoni Morou, a postdoctoral fellow in Kaufmann's lab, identified major functional differences between the two groups of patients in the study. The HIV controllers had much more robust immune responses, known as Th17 and Th22, which are important for the defence of the gastrointestinal tract, for example. But chronically infected patients with high levels of viral replication showed dysregulated CD4 T cells targeting HIV, and some of their cell subsets showed signs of abnormal functioning.

New therapies ahead?

Continuing their investigation, the CRCHUM scientists wondered whether ART leads to an immune response akin to the one found in HIV controllers. "We followed up chronically infected patients after control of the virus by ART and checked if the treatment can 'repair their immune system' and allow them to have CD4 T cells with features similar to those of the HIV controllers," said Kaufmann, a professor at Université de Montréal.

The result was double-edged: some gene modules were sensitive to ART, while others turned out to be expressed very differently than in HIV controllers.

"We showed that ART leaves unrepaired holes in the immune system's wall of defence," said Kaufmann. "Our results suggest that some of these long-lasting defects may contribute to the lack of viral control once the antiretroviral therapy is interrupted. We now know which holes linger in the immune system. Do we have to fill them in, and if so, how? This is another science question."

Paving the way to new therapies that could complement ART, Kaufmann's team identified important features of an effective HIV specific immune response compared to a dysfunctional one and showed how the response can be affected by ART.

The next step will be to study the underlying programming of these CD4 T cells (epigenetics) in the hope of developing new targeted strategies to reverse immune dysfunction and complement ART. Kaufmann's lab is now using the same approach to evaluate candidates for an HIV vaccine.

In 2017, nearly 37 million people were living with HIV. Every day, 5,000 new infections are reported to health authorities around the world.

New Rochelle, NY, July 11, 2019–Cells equipped with superparamagnetic iron oxide nanoparticles (SPIOs) can be directed to a specific location by an external magnetic field, which is beneficial for tissue repair. Researchers have now taken the important step of evaluating the safety and efficacy of magnetically labeled mesenchymal stem cells (MSCs) for use in repairing cartilage defects. The study is published in Tissue Engineering, a peer-reviewed journal from Mary Ann Liebert, Inc., publishers. Click here to read the article for free on the Tissue Engineering website through August 11, 2019.

Naosuke Kamei, MD, PhD, Hiroshima University, Hiroshima, Japan, and colleagues present their work in an article titled “In Vitro Safety and Quality of Magnetically Labeled Human Mesenchymal Stem Cells Preparation for Cartilage Repair”. The authors demonstrated the safety of magnetically labeled MSCs based on karyotyping, colony formation assays, and total proliferation, finding only negligible differences after labeling. Chondrocyte differentiation and reactivity to magnetic forces were monitored to evaluate cell quality, and these results indicated that the appropriate titration of SPIO density is advisable to optimize differentiation capacity while maintaining magnetic attraction.

“The dedicated delivery of MSC’s to the defect site is a major step forward in the clinical use of MSC’s for tissue regeneration,” says Tissue Engineering Methods Co-Editor-In-Chief John A. Jansen, DDS, PhD, Professor and Head, Department of Biomaterials, Radboud University Medical Center.

About the Journal

Tissue Engineering is an authoritative peer-reviewed journal published monthly online and in print in three parts: Part A, the flagship journal published 24 times per year; Part B: Reviews, published bimonthly, and Part C: Methods, published 12 times per year. Led by Co-Editors-in-Chief Antonios G. Mikos, PhD, Louis Calder Professor at Rice University, Houston, TX, and John P. Fisher, PhD, Fischell Family Distinguished Professor & Department Chair, and Director of the NIH Center for Engineering Complex Tissues at the University of Maryland, the Journal brings together scientific and medical experts in the fields of biomedical engineering, material science, molecular and cellular biology, and genetic engineering. Leadership of Tissue Engineering Parts B (Reviews) and Part C (Methods) is provided by Katja Schenke-Layland, PhD, Eberhard Karls University, Tübingen, Heungsoo Shin, PhD, Hanyang University; and John A. Jansen, DDS, PhD, Radboud University, and Xiumei Wang, PhD, Tsinghua University respectively. Tissue Engineering is the official journal of the Tissue Engineering & Regenerative Medicine International Society (TERMIS). Complete tables of content and a sample issue may be viewed on the Tissue Engineering website.

About the Publisher

Mary Ann Liebert, Inc., publishers is a privately held, fully integrated media company known for establishing authoritative peer-reviewed journals in many promising areas of science and biomedical research, including Stem Cells and Development, Human Gene Therapy, and Advances in Wound Care. Its biotechnology trade magazine, GEN (Genetic Engineering & Biotechnology News), was the first in its field and is today the industry’s most widely read publication worldwide. A complete list of the firm’s 80 journals, books, and newsmagazines is available on the Mary Ann Liebert, Inc., publishers website.

DOI

10.1089/ten.tec.2019.0001

Irvine, Calif., July 15, 2019 - Since its invention by a Hungarian architect in 1974, the Rubik's Cube has furrowed the brows of many who have tried to solve it, but the 3D logic puzzle is no match for an artificial intelligence system created by researchers at the University of California, Irvine.

DeepCubeA, a deep reinforcement learning algorithm programmed by UCI computer scientists and mathematicians, can find the solution in a fraction of a second, without any specific domain knowledge or in-game coaching from humans. This is no simple task considering that the cube has completion paths numbering in the billions but only one goal state - each of six sides displaying a solid color - which apparently can't be found through random moves.

For a study published today in Nature Machine Intelligence, the researchers demonstrated that DeepCubeA solved 100 percent of all test configurations, finding the shortest path to the goal state about 60 percent of the time. The algorithm also works on other combinatorial games such as the sliding tile puzzle, Lights Out and Sokoban.

"Artificial intelligence can defeat the world's best human chess and Go players, but some of the more difficult puzzles, such as the Rubik's Cube, had not been solved by computers, so we thought they were open for AI approaches," said senior author Pierre Baldi, UCI Distinguished Professor of computer science. "The solution to the Rubik's Cube involves more symbolic, mathematical and abstract thinking, so a deep learning machine that can crack such a puzzle is getting closer to becoming a system that can think, reason, plan and make decisions."

The researchers were interested in understanding how and why the AI made its moves and how long it took to perfect its method. They started with a computer simulation of a completed puzzle and then scrambled the cube. Once the code was in place and running, DeepCubeA trained in isolation for two days, solving an increasingly difficult series of combinations.

"It learned on its own," Baldi noted.

There are some people, particularly teenagers, who can solve the Rubik's Cube in a hurry, but even they take about 50 moves.

"Our AI takes about 20 moves, most of the time solving it in the minimum number of steps," Baldi said. "Right there, you can see the strategy is different, so my best guess is that the AI's form of reasoning is completely different from a human's."

The veteran computer scientist said the ultimate goal of projects such as this one is to build the next generation of AI systems. Whether they know it or not, people are touched by artificial intelligence every day through apps such as Siri and Alexa and recommendation engines working behind the scenes of their favorite online services.

"But these systems are not really intelligent; they're brittle, and you can easily break or fool them," Baldi said. "How do we create advanced AI that is smarter, more robust and capable of reasoning, understanding and planning? This work is a step toward this hefty goal."

Orange juice is a staple on many breakfast tables, but the future availability of citrus products is threatened by the global spread of huanglongbing (HLB), also known as citrus greening disease.

Knowing which environmental conditions are suitable for disease transmission and where those conditions occur is vital for crop management. A new study published by researchers at Virginia Tech with a team of international researchers in Journal of Applied Ecology investigates the thermal suitability for transmission of citrus greening with implications for surveillance and prevention.

The bacterium responsible for causing citrus greening prevents the formation of commercially viable fruit and is transmitted by an insect called the Asian citrus psyllid.

Both the pathogen and the insect vector have been spreading in recent years, devastating regions famous for high citrus production and threatening the future of the citrus industry. As citrus greening becomes an increasing threat to growers worldwide, the future of the industry may depend on identifying locations that do not have a high risk of production collapse.

Led by Rachel Taylor of the Animal and Plant Health Agency (APHA) in the United Kingdom, the team of researchers behind the study created a mathematical model to calculate how suitability for citrus greening transmission depends on temperature and mapped how this translates into areas where the disease could become established.

"Our suitability maps can be used to underpin risk-based surveillance and prevention to ensure resources to fight citrus greening are applied in the best locations," Taylor said.

Disease transmission dynamics are largely dependent on temperature, both for successful replication of the HLB bacterium and survival of psyllid vectors. The model was built with data collected under laboratory conditions, directly incorporating the effects and limitations of environmental temperature into the estimate of suitability.

"Although the approach is fairly simple, we've shown in other systems that we can make surprisingly accurate predictions," said coauthor Leah Johnson, assistant professor in Department of Statistics in the College of Science at Virginia Tech.

The model predicts that successful infection of host plants can occur between 16?C and 33?C, with peak transmission at around 25?C. Using this information of the temperature limits for disease spread, the authors were able to make maps of global suitability, showing how many months of the year have temperature conditions that would place citrus groves at risk for infection with HLB. Perhaps unsurprisingly, many regions with nearly year-round suitability for citrus greening include some of the citrus-growing areas hit hardest by the disease, including Brazil and South-East Asia.

This work provides critical information for citrus production and crop management moving into the future. "Translating these models into maps helps communicate our findings to citrus stakeholders and creates a baseline for thinking about potential climate change impacts," said coauthor Sadie Ryan, from the University of Florida.

Some locations identified by the model as suitable for transmission for half of the year, such as California and the Iberian Peninsula, are currently free of citrus greening. In these areas known for high citrus production, preventing the establishment of the disease vector through increased surveillance and management may help prevent the devastating effects that citrus greening has had on other growers.

"We hope that this model can be a useful planning tool for growers and policymakers dealing with HLB," said Johnson, who is also an affiliated faculty member of the Global Change Center, an arm of the Fralin Life Sciences Institute at Virginia Tech.

What The Study Did: An observational study based on a group of smokers and former smokers in France looked at whether electronic cigarette use was associated with changes in the number of cigarettes smoked, with smoking cessation rates among smokers, and with smoking relapse among former smokers.

Authors: Ramchandar Gomajee, M.Sc., of the Sorbonne Université in Paris, is the corresponding author.

(doi:10.1001/jamainternmed.2019.1483)

Editor's Note: The article includes conflict of interest and funding/support disclosures. Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc.

WASHINGTON -- Belief in the "racist police officer" stereotype may become a self-fulfilling prophecy for law enforcement officers and lead to increased support for forceful or threatening policing tactics, according to research published by the American Psychological Association.

"Officers who were highly concerned about appearing racist reported lower confidence in their moral authority, and that led to them reporting more support for using coercive policing while on the job," said Phillip Atiba Goff, PhD, of the Center for Policing Equity and John Jay College of Criminal Justice. He is co-author of the study published in Law and Human Behavior. "Interestingly, both white and non-white officers were equally likely to be concerned about appearing racist. The potential negative influence of stereotype threats such as the 'racist police officer' should be a concern to all officers and communities."

Given the current tensions in the U.S. between law enforcement and the public, and notably with racial and ethnic minorities, Goff and his colleagues wanted to better understand how pervasive stereotypes influence officers and how they approach members of their community.

"Police are typically trained to use their moral authority as peace officers to resolve conflicts, but if that moral authority is called into question, they may feel they have limited tools to gain compliance, leading to more harmful actions with potentially disastrous results," said Rick Trinkner, PhD, of Arizona State University, the study's lead author.

The researchers surveyed 784 patrol officers and sergeants from the patrol division of a large urban police force. Over eight weeks, they attended patrol roll call at every station within the department to distribute and collect the surveys. Respondents were 80% male, nearly all were patrol officers and just over half of the sample reported being white. On average, the officers were in their early 40s and had 14 years of experience.

The survey asked questions about stereotype threats (e.g., "How much do you worry that people may think of you as racist because you are a police officer?"), self-legitimacy (e.g., "How confident are you in using the authority that has been given to you as a police officer?"), resistance to their department's use of force policy (e.g., "How justifiable are violations of the department's use of force policies?") and approval of unreasonable force (e.g., "How much would you approve of a police officer striking a community resident who had said vulgar or obscene things to the officer?"). Responses were measured on a scale from one (not at all) to five (completely/always).

The researchers also examined officers' support for engaging with the public in a just manner (e.g., "How much of a waste of time do you think it is to explain your decision to community members?") as well as officers' level of cynicism and perception of risk associated with the job.

"We found what appears to be a vicious cycle: The more an officer was worried about being perceived as racist, the less confidence they had in their authority and the more likely they were to condone abusive policing tactics," said Trinkner. "The same was true for officers who reported being more cynical about their line of work."

The more dangerous officers believed their job to be, the more confidence they had, but they more often believed that interactions with community members required more force than allowed by department policy, said Trinkner.

The researchers also found that age was a strong predictor of support for responsible use of force, as older officers reported more self-confidence and less support for coercive policing than younger policemen and -women, according to the study.

"This suggests that older officers may be especially well-positioned within a department to socialize younger officers to norms that are less aggressive, but likely cultivated with a more seasoned exposure to the work," said Erin M. Kerrison, PhD, of the University of California, Berkeley, study co-author. "Ensuring that everyone gets home safely, in even the most dangerous encounters, is a skill that newer officers are less likely to have honed."

Results also showed that more women police officers supported working with the public in a just manner. This finding could indicate that recruitment, training and counseling efforts that addressed the imminent violence associated with toxic masculinity, for example, could improve the quality of policing, according to Kerrison.

"Police misconduct is not just a black and white issue," said Kerrison. "Many studies highlight a range of state practices resulting in the disproportionate policing of black, latino and indigenous adolescent boys, the criminalization of homeless transgender youth and the second chances disproportionately granted to under-policed white women. These trends suggest that the intersection of race and gender perception and performance is a recurring precursor to state abuse victimization. Data from our study also highlight a need for ongoing research that explores whether officers see their gender identities wrapped up in the ways they identify and diffuse perceived threats."

The authors said these findings show that the relationship between law enforcement and the public is complex and requires much more attention in order to ensure public safety.

"Conversations about police officers and stereotypes typically focus on the prejudices that officers bring with them on patrol, but this discourse needs to expand to include the beliefs that officers have about themselves and how that affects their work and relationships within their communities," said Goff. "Opening up these types of dialogues can potentially be the difference between an encounter that increases mutual trust and respect and one in which harmful stereotypes are reinforced."

Researchers successfully reconstructed anthropic influences on sedimentation, including dredging and canal gates use, in the ancient harbour of Portus - a complex of harbour basins and canals that formed the hub of commerce in the capital of the Roman Empire.

The findings suggest that the Romans were proactively managing their river systems from earlier than previously thought - as early as the 2nd century AD.

The history was reconstructed using a range of high-resolution sediment analysis including piston coring, x-ray scanning, radiocarbon dating, magnetic and physical properties and mineral composition of the ancient harbour sediments.

La Trobe University Archaeology Research Fellow and marine geologist, Dr Agathe Lisé-Pronovost, said that ancient harbours can accumulate sediments more rapidly than natural environments, which is the case of Portus built in a river delta and where sediment accumulated at a rate of about one meter per century. Applying these methods allowed researchers to date and precisely reconstruct the sequence of events of the historical port, including dredging to maintain enough draught and canal gate use.

"Dating ancient harbour sediments is a major challenge, given ports are not only subjected to weather events throughout history, but the lasting effects of human activity," Dr Lisé-Pronovost said.

"The methods we've applied have allowed us to address the dating issue and routine measurements of the sort could greatly improve chronostratigraphic analysis and water depth reconstruction of ancient harbour deposits."

Dr Lisé-Pronovost and her team encourage geoarchaeologists to implement these innovative methods to their work.

Developing synthetic materials that are as dynamic as those found in nature, with reversibly changing properties and which could be used in manufacturing, recycling and other applications, is a strong focus for scientists.

In a world-first, researchers from Queensland University of Technology (QUT), Ghent University (UGent) and Karlsruhe Institute of Technology (KIT) have pioneered a novel, dynamic, reprogrammable material - by using green LED light and, remarkably, darkness as the switches to change the material's polymer structure, and using only two inexpensive chemical compounds. One of these compounds, naphthalene, is well known as an ingredient in moth repellents.

The new dynamic material could potentially be used as a 3D printing ink to print temporary, easy-to-remove support scaffolds. This would overcome one of the current limitations of the 3D process to print free-hanging structures.

The research is part of an ongoing international collaboration between QUT macromolecular chemist and Australian Research Council Laureate Fellow Professor Christopher Barner-Kowollik, Dr Hannes Houck, who recently completed his PhD across QUT, UGent and KIT, UGent Professor Filip Du Prez, and KIT's Dr Eva Blasco.

Their findings have been published in the paper 'Light-Stabilized Dynamic Materials' in the Journal of the American Chemical Society (JACS).

Key points:

The new material was formed with naphthalenes and the coupling molecules triazolinediones (TADs)

As long as green LED light shone on the material it remained stable and strong

Once the light was off and the material was kept in darkness, the chemical bonds of the network structure broke up and the material became soft and liquefied

The hard-to-soft process could be repeated with the flick of the switch, and the light could be dimmed to modulate the mechanical properties of the material

Follow on research is looking at other chemical combinations that can achieve the same result

Professor Barner-Kowollik, from QUT's Science and Engineering Faculty, said what makes the discovery unique is that light is used as the trigger to stabilise, rather than destroy, chemical bonds - so the researchers have coined a new term, light-stabilised dynamic materials (LSDMs).

"We are hoping to introduce LSDMs as a whole new class of materials," said Dr Houck. "We debated whether to patent the new material, but decided not to wait and to publish the findings to advance knowledge and understanding of the processes involved."

The researchers said what they have achieved is the opposite of what is usually done in chemistry and "many people didn't think it could be done".

"Typically, you use different wavelengths of light or additional heat or harsh chemicals to break up the polymer molecule chains that form a network structure," they said.

"However, in this case, we used green LED light to stabilise the network. The trigger to break up the network, make it collapse and flow away is actually the mildest one of all: darkness. Switch the light back on and the material re-hardens and retains its strength and stability.

"This is what you call an out-of-equilibrium chemical system. The constant energy of the green light keeps the chemical system in this bonded form, pushing it out of its equilibrium. Take away the light, and the system goes back to its relaxed, lowest energy state."

Professor Barner-Kowollik said the researchers had already been contacted by 3D printing technology companies interested in application of the research.

3D printing is used in the aerospace and automotive industries to make intricate parts and detailed prototypes.

However, 3D printing complex designs with overhangs or bridges is difficult or off limits because the 3D process involves printing layer upon layer, and there is no direct support for layers in sharply angled structures.

"What you need to 3D print something like a bridge is a support scaffold, a second ink that provides that scaffold during printing of the design, but which you can later remove when it is no longer needed," he said.

"With a light-stabilised dynamic ink used as a scaffold you could 3D print under light, then switch the light off to let the scaffold ink flow away."

Professor Du Prez and Professor Barner-Kowollik said another potential application for LSDMs was as a cell biology study tool, with biologists using it as a cell surface support they could alter by light modulation without damaging the cells.

The European eel (Anguilla anguilla), the freshwater blenny (Salaria fluviatilis), the freshwater pearl mussel (Margaritifera auricularia) and the pronged clubtail (Gomphus graslini) are some of the vulnerable species that are not represented enough in the biodiversity catalogue of the Natural River Basins (RNF) in Spain, according to a new article published in the journal Aquatic Conservation: Marine and Freshwater Ecosystems -in which researchers Miguel Cañedo-Argüelles and Núria Bonada, from the Research Group Freshwater Ecology, Hydrology and Management (FEHM) of the University of Barcelona take part.

The new science article -focused on the Ebro River basin- adds for the first time the participation of the citizens and other social and institutional agents (water agencies, hydrographic confederations, scientists, non-governmental organizations, environment consultants, etc.) in the designing process for the water reserves map in Spain. Other participants in the study are the experts Virgilio Hermoso (Forest Science and Technology Center of Catalonia, CTFC), Tony Herrera (New Water Culture Foundation, FNCA), and José Barquín (University of Cantabria).

Reservial Project: protecting river areas with the highest ecological and socioenvironmental value

The Natural River Basins (RNF) were created in Spain in 2015 to preserve the river areas with no human intervention and which were in a perfect ecological state. The new study reveals the first conclusions of Reservial (2015-2017), a pioneering project in the European framework to assess the efficiency of the RNF in Spain with the people's and involved social agents' consensus.

This innovating project wants to shape a network of water basins to represent the rivers in Spain so as to guarantee the protection of the river spots with the highest ecological and socioenvironmental value as well as the preservation of the water biodiversity. Reservial is led by Núria Bonada, lecturer from the Department of Evolutionary Biology, Ecology and Environmental Sciences and the Biodiversity Research Institute (UB-IRBio) of the UB, and counts on the participation of the New Water Culture Foundation (FNCA) and BBVA Foundation.

With public participation in the research protocol, experts define the conservation criteria RNF should fulfil to guarantee the protection of biodiversity related to rivers. "About 60% of the species that were assessed in the project are not enough represented in the RNF. Some of these species are regarded as vulnerable according to the International Union for Conservation of Nature (IUCN) Red List of Threatened Species", notes Miguel Cañedo-Argüelles, member of the FEHM-UB research group and the Water Research Institute (IdRA) of the University of Barcelona.

"Therefore, social and scientific and technical requirements demand an additional effort to bring the element of biodiversity as a strategic criteria when assigning the RNF in a certain river basin", adds Cañedo-Argüelles.

Still many types of river areas to represent

Apart from protecting biodiversity, the sectors said RNF should be regarded as effective ecological corridors which can include all water typologies of the country. Those declared RNF are almost exclusively located I mountains and leave aside the mid and low stretches of rivers, which are usually degraded or with a little-studied ecological state.

"As a result, current RNF are not connected to each other and do not favour the interrelation between populations of different species in the fluvial ecosystems. This disconnection is one of the main causes for the extinction of the species, according to the Platform for Biodiversity and Ecosystem Services", warns the lecturer Núria Bonada (UB-IRBio), who also leads the Freshwater Ecology, Hydrology and Management (FEHM) research group of the University of Barcelona.

From a methodological perspective, the research team applied a planning program for conservation -designed by the University of Queensland (Australia), known as Marxan, to identify the rivers stretches that should be added in the current RNF network to fulfil the objectives stated by the involved sectors in the study. Marxan could be a useful and efficient tool for the administrations with competences on management and conservation of water ecosystems since it enables the creation of maps showing priority areas to be protected in order to fulfill the objectives.

"This tool could help contribute to improve the current RNF network in the future, and through the corresponding processes of citizen participation, it could involve the people in the conservation of our water ecosystems", note Miguel Cañedo-Argüelles and Núria Bonada.

Social consensus to guarantee protection and conservation of rivers

According to the new study, citizen participation in the systematic planning of conservation could improve the protection of freshwater ecosystems in the country to integrate a wide variety of preferences in the design of RNF.

"Having detailed and updated information on the distribution of invasive species or threatened ones -apart from conducting frequent comprehensive ecological monitoring- are essential elements to respond to the social requirements in order to improve the protection of biodiversity in freshwater ecosystems and preserve natural environments with a high ecological value", conclude the authors.

Podcast post-embargo link: https://soundcloud.com/cmajpodcasts/190559-com

Strong political support and strong public health systems are necessary to combat measles outbreaks, which are growing in frequency around the world, argue public health experts in a commentary in CMAJ (Canadian Medical Association Journal).

"Sustaining measles elimination requires strong regional public health systems," write Drs. Natasha Crowcroft and Shelly Bolotin, Public Health Ontario and Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario. "In a globalized society in which we are all connected, a disease as infectious as measles -- the most infectious of the vaccine-preventable diseases -- is easily spread. To prevent this, public health programs need to deliver close to 100% immunization coverage, which is challenging on a technical level."

The World Health Organization reports a 300% increase in cases of measles in the first 3 months of 2019 compared with 2018.

"In the war against microbes, victories are achieved at a huge price, and the peace that follows is fragile," write the authors. "It took many years for the Americas to verify elimination of measles in 2016. It took only 2 years of political disruption in Venezuela to disrupt the health system enough to obliterate this achievement."

Ensuring that everyone is vaccinated is complex and requires coordination at the local level, which is undermined by the pockets of anti-vaccination proponents. Strong public health systems are needed to ensure everyone is immunized and to track this uptake accurately.