Culture

The legalization of marijuana for Washington state adults may be thwarting a steady downward trend in teen marijuana use, according to new research from the University of Washington.

The longitudinal study of more than 230 teens and young adults finds that teens may be more likely to use marijuana following legalization -- with the proliferation of stores and increasing adult use of the drug -- than they otherwise would have been.

"When we think about marijuana legalization, a worry is that underage use may go up," said Jennifer Bailey, the study's lead author and principal investigator with the Social Development Research Group in the UW School of Social Work. "Early use and heavy use during adolescence can have a lot of negative health consequences, then and later in life, so we don't want teen use to be going up."

Bailey notes that before marijuana legalization, rates of teen marijuana use and other drug use had both been decreasing over the last couple of decades.

The study was published July 9 in the American Journal of Preventive Medicine.

Researchers examined whether marijuana legalization led to teen use of the drug, as well as teens' perceptions that the drug is harmful. Controlling for age, sex, race and parent education of the participants, researchers found that kids who entered their teens more recently were less likely to report they'd used marijuana in the past year. For example, 11% of kids born before 2000 reported using marijuana over the past year at age 15, but only 5% of kids born after 2000
said they used marijuana at age 15.

That finding goes along with the general downward trend in teen substance use. But it was after accounting for this trend that the effect of legalization showed up, Bailey said.

Controlling for the year when kids were born, teens interviewed after voter approval in 2012 of nonmedical marijuana were several times more likely to report they'd used marijuana in the past year. Bailey thinks this means that marijuana legalization may be working against the decreases in teen substance use seen in the recent past.

The new findings differ slightly from other studies showing that rates of underage marijuana use are holding steady or dropping a little after legalization. UW researchers say this may reflect methodology. The UW study was able to account for long-term trends in teen drug use by following kids born between 1989 and 2002 for 15 years and comparing kids who were teenagers before legalization to those who were teenagers after legalization. Other studies have used school-based or optional surveys to assess a larger population at once, and have not always accounted for long-term trends.
Those methods supply important information too, Bailey said. They just reflect a different angle on the issue. Broader, point-in-time surveys don't look at individual change.

"They can only see how a whole state changes over time," Bailey said. "Data like ours let you look at individuals and how drug use and behavior change over time, and then we can relate that to changes in policy."

The participants in the UW research are some of the children of participants in a larger and older longitudinal study: the Seattle Social Development Project. That study has followed hundreds of people -- since they were fifth-graders in Seattle elementary schools in the 1980s --to evaluate an assortment of conditions, behaviors and life choices. The results from interviews with 233 of their children, pre- and post-marijuana legalization, were included in this new study.

Child participants ranged in age from 1 to 13 years old when the study began in 2002; marijuana use was assessed from ages 10 to 20. Researchers found that children in the sample entering their teens more recently were more likely to perceive the drug as harmful. For example, 69% of 15-year-olds born before 2000 said regular marijuana use is harmful, but 77% of 15-year-olds born after 2000 said using marijuana regularly is harmful. Bailey attributes this to years of drug prevention and education efforts in schools and communities.

The study did not, however, find an overall association between marijuana legalization and teens' perceived harm from the drug. It could be that changing societal attitudes drive changes in marijuana laws, the authors noted, rather than that changing laws drive perceptions.

Researchers study the perception of harm because people are more likely to engage in a behavior they see as relatively risk-free, Bailey said. In the 1960s and 1970s, for instance, there was a generally low perception of harm from many drugs, and usage was higher than it was in subsequent decades, when perceived harm increased.

"People generally like to take care of themselves. They don't typically do things that carry risk of harm. Throughout the decades that we've been tracking marijuana use, this highly correlates with whether someone will use or not," she said.

The UW study also found no connection between marijuana legalization and teen cigarette smoking; the use of one substance often goes with the other, Bailey said. Teen smoking nationwide has declined precipitously for years, which has been attributed to higher taxes, greater restrictions and widespread public health marketing.

Researchers are watching closely to see whether recent dramatic increases in vaping among teens affect declines in teen smoking rates.

Similar studies in other states where marijuana has been legalized -- the participants in this study lived almost exclusively in Washington state -- could provide further evidence of links between laws and behavior, Bailey said. Currently, nearly a dozen states permit the sale of marijuana for nonmedical use; an additional 22 states allow the drug for medical purposes only.

Nonetheless, the UW findings can help inform prevention messages targeting teens and marijuana, Bailey said.

"A teen usage rate that holds steady isn't good enough if it would normally be going down. We need to devote more attention to prevention of adolescent use in the context of legalization because we want to keep the decreases we've been seeing before legalization was implemented," Bailey said.

SAN ANTONIO, Texas, USA -- Genes and cardiovascular health each contribute in an additive way to a person's risk of dementia, U.S. researchers including Sudha Seshadri, MD, and Claudia Satizabal, PhD, of The University of Texas Health Science Center at San Antonio (UT Health San Antonio) reported July 20 in the journal Neurology.

The study was conducted in 1,211 participants in the Framingham Heart Study and involved collaborators from Boston University.

Participants with a high genetic risk score based on common genetic variants, including having an allele called apolipoprotein E (APOE) ε4, were at a 2.6-fold higher risk of developing dementia than subjects who had a low risk score and did not carry the APOE ε4 allele.

Having favorable cardiovascular health, as defined by an index of the American Heart Association, was associated with a 0.45-fold lower risk of dementia compared to having unfavorable cardiovascular health, the study also showed.

"The connection between heart health and brain health becomes clearer with each finding," Dr. Seshadri, senior investigator in the Framingham Heart Study, said. She is professor of neurology in the Long School of Medicine at UT Health San Antonio and founding director of the university's Glenn Biggs Institute for Alzheimer's and Neurodegenerative Diseases.

"We hope that the results of this study will send the public a message, and that message is to exercise, reduce stress and eat a healthy diet," Dr. Seshadri said. "Then, regardless of your genes, you have the potential to lower your risk of dementia."

"It is imperative to start today," Dr. Satizabal, assistant professor of population health sciences and Biggs Institute investigator, said. "It seems, from our findings, that having favorable cardiovascular health mitigates the risk of dementia in persons with high genetic risk."

Respiratory droplets from a cough or sneeze travel farther and last longer in humid, cold climates than in hot, dry ones, according to a study on droplet physics by an international team of engineers. The researchers incorporated this understanding of the impact of environmental factors on droplet spread into a new mathematical model that can be used to predict the early spread of respiratory viruses including COVID-19, and the role of respiratory droplets in that spread.

The team developed this new model to better understand the role that droplet clouds play in the spread of respiratory viruses. Their model is the first to be based on a fundamental approach taken to study chemical reactions called collision rate theory, which looks at the interaction and collision rates of a droplet cloud exhaled by an infected person with healthy people. Their work connects population-scale human interaction with their micro-scale droplet physics results on how far and fast droplets spread, and how long they last.

Their results were published June 30 in the journal Physics of Fluids.

"The basic fundamental form of a chemical reaction is two molecules are colliding. How frequently they're colliding will give you how fast the reaction progresses," said Abhishek Saha, a professor of mechanical engineering at the University of California San Diego, and one of the authors of the paper. "It's exactly the same here; how frequently healthy people are coming in contact with an infected droplet cloud can be a measure of how fast the disease can spread."

They found that, depending on weather conditions, some respiratory droplets travel between 8 feet and 13 feet away from their source before evaporating, without even accounting for wind. This means that without masks, six feet of social distance may not be enough to keep one person's exhalated particles from reaching someone else.

"Droplet physics are significantly dependent on weather," said Saha. "If you're in a colder, humid climate, droplets from a sneeze or cough are going to last longer and spread farther than if you're in a hot dry climate, where they'll get evaporated faster. We incorporated these parameters into our model of infection spread; they aren't included in existing models as far as we can tell."

The researchers hope that their more detailed model for rate of infection spread and droplet spread will help inform public health policies at a more local level, and can be used in the future to better understand the role of environmental factors in virus spread.

They found that at 35C (95F) and 40 percent relative humidity, a droplet can travel about 8 feet. However, at 5C (41F) and 80 percent humidity, a droplet can travel up to 12 feet. The team also found that droplets in the range of 14-48 microns possess higher risk as they take longer to evaporate and travel greater distances. Smaller droplets, on the other hand, evaporate within a fraction of a second, while droplets larger than 100 microns quickly settle to the ground due to weight.

This is further evidence of the importance of wearing masks, which would trap particles in this critical range.

The team of engineers from the UC San Diego Jacobs School of Engineering, University of Toronto and Indian Institute of Science are all experts in the aerodynamics and physics of droplets for applications including propulsion systems, combustion or thermal sprays. They turned their attention and expertise to droplets released when people sneeze, cough or talk when it became clear that COVID-19 is spread through these respiratory droplets. They applied existing models for chemical reactions and physics principles to droplets of a salt water solution--saliva is high in sodium chloride--which they studied in an ultrasonic levitator to determine the size, spread, and lifespan of these particles in various environmental conditions.

Many current pandemic models use fitting parameters to be able to apply the data to an entire population. The new model aims to change that.

"Our model is completely based on "first principles" by connecting physical laws that are well understood, so there is next to no fitting involved," said Swetaprovo Chaudhuri, professor at University of Toronto and a co-author. "Of course, we make idealized assumptions, and there are variabilities in some parameters, but as we improve each of the submodels with specific experiments and including the present best practices in epidemiology, maybe a first principles pandemic model with high predictive capability could be possible."

There are limitations to this new model, but the team is already working to increase the model's versatility.

"Our next step is to relax a few simplifications and to generalize the model by including different modes of transmission," said Saptarshi Basu, professor at the Indian Institute of Science and a co-author. "A set of experiments are also underway to investigate the respiratory droplets that settle on commonly touched surfaces."

(JACKSON, Wyo. - July 20, 2020) - In 2018, cyanobacteria from nutrient-rich waters in Lake Okeechobee were released down the Caloosahatchee river at the same time that red tides were gathering along the Florida west coast, potentially exposing coastal residents to a mixture of toxins. In 2018, releases of cyanobacterial-laden freshwater from Lake Okeechobee transported a large bloom of Microcystis cyanobacteria down the Caloosahatchee. Analysis of water samples showed high concentrations of microcystin-LR, sufficient to result in adverse human and animal health effects if ingested, based on the known toxicity of this cyanotoxin.

The microcystin liver toxin was being produced by Microcystis, while at the same time, potent neurotoxins called brevetoxin were released from the marine dinoflagellate Karenia brevis in the Gulf of Mexico. In addition, BMAA, a neurotoxin suspected of being linked to neurodegenerative diseases such as ALS and Alzheimer's disease, was detected in samples of cyanobacteria, dinoflagellates, and diatoms along the Caloosahatchee and west coast. Furthermore, cyanobacterial mats collected on the west coast in 2019 also showed high concentrations of BMAA to be present.
Together, these new findings highlight the potential for multiple, potentially toxic blooms to co-exist with unknown implications for human and animal health.

"We have been monitoring Florida waters for cyanobacterial toxins since the 2016 emergency release of Lake Okeechobee water down the St. Lucie River and the Caloosahatchee," Dr. James Metcalf, first author and Senior Research Scientist at the Brain Chemistry Labs in Jackson Hole reported. "We are concerned that cyanobacterial releases from Lake Okeechobee down these two rivers continue to occur."

Red tides have historically resulted in fish kills and seasonal respiratory irritation along the west coast of Florida, but this new discovery of multiple sources of cyanobacterial toxins occurring at the same time as red tides, requires further investigation says scientists.

"Together with our colleagues at the Miami Brain Endowment Bank, we have found that chronic dietary exposure of laboratory animals to the cyanobacterial toxin BMAA triggers early Alzheimer's and ALS neuropathology," explains Dr. Paul Alan Cox, Director of the Brain Chemistry Labs, " but we cannot predict the health impacts of chronic exposures to multiple toxins at the same time."

ITHACA, N.Y. - In a potential breakthrough in wearable sensing technology, researchers from Cornell University and the University of Wisconsin, Madison, have designed a wrist-mounted device that continuously tracks the entire human hand in 3D.

The bracelet, called FingerTrak, can sense and translate into 3D the many positions of the human hand, including 20 finger joint positions, using three or four miniature, low-resolution thermal cameras that read contours on the wrist. The device could be used in sign language translation, virtual reality, mobile health, human-robot interaction and other areas, the researchers said.

"This was a major discovery by our team - that by looking at your wrist contours, the technology could reconstruct in 3D, with keen accuracy, where your fingers are," said Cheng Zhang, assistant professor of information science and director of Cornell's new SciFi Lab, where FingerTrak was developed. "It's the first system to reconstruct your full hand posture based on the contours of the wrist."

Past wrist-mounted cameras have been considered too bulky and obtrusive for everyday use, and most could reconstruct only a few discrete hand gestures.

FingerTrak's breakthrough is a lightweight bracelet, allowing for free movement. Instead of using cameras to directly capture the position of the fingers, the focus of most prior research, FingerTrak uses a combination of thermal imaging and machine learning to virtually reconstruct the hand. The bracelet's four miniature, thermal cameras - each about the size of a pea - snap multiple "silhouette" images to form an outline of the hand.

A deep neural network then stitches these silhouette images together and reconstructs the virtual hand in 3D. Through this method, Zhang and his fellow researchers were able to capture the entire hand pose, even when the hand is holding an object.

While the technology has a wide range of possible uses, Zhang said the most promising is its potential application in sign language translation.

"Current sign language translation technology requires the user to either wear a glove or have a camera in the environment, both of which are cumbersome," he said. "This could really push the current technology into new areas."

FingerTrak could also have an impact on health care applications, specifically in monitoring disorders that affect fine-motor skills, said Yin Li, assistant professor of biostatistics and medical informatics at the University of Wisconsin, Madison School of Medicine and Public Health, who contributed to the software behind FingerTrak.

"How we move our hands and fingers often tells about our health condition," Li said. "A device like this might be used to better understand how the elderly use their hands in daily life, helping to detect early signs of diseases like Parkinson's and Alzheimer's."

"FingerTrak: Continuous 3D Hand Pose Tracking by Deep Learning Hand Silhouettes Captured by Miniature Thermal Cameras on Wrist," was published in the Proceedings of the Association for Computing Machinery on Interactive, Mobile, Wearable and Ubiquitous Technologies. It also will be presented at the 2020 ACM International Joint Conference on Pervasive and Ubiquitous Computing, taking place virtually Sept. 12-16.

Toddlers may not be able to describe their feelings of uncertainty, but a new study from the Center for Mind and Brain at the University of California, Davis provides evidence that toddlers may experience and deal with uncertainty in decision making in the same way as older children and adults.

"Little children show behaviors that suggest they can respond to uncertain situations. For example, they seem to hesitate or ask when they can't figure something out," said Simona Ghetti, professor of psychology at UC Davis. "But are these behaviors grounded in their evaluations of actual evidence? And how do very young children become aware they are uncertain?"

The new study, involving 160 toddlers from 25 to 32 months old, provides a window into how young children's minds work as they perform a task, she said. The work is published July 20 in Nature Human Behavior.

First author Sarah Leckey, graduate student in the Center for Mind and Brain, led the experimental work. In the study, 2-year-olds were shown pairs of images of animals or common objects, each mostly obscured by a grey square. They were asked to find one of the objects, for example "where is the elephant hiding?"

The task was carried out with both an eye-tracking device, where toddlers responded by pointing, and a touch screen, which allowed to collect their response speed. The experiment was conducted twice, with two groups of 80 children, to ensure reproducibility of the results.

Tracking gaze and behavior

By following the childrens' gaze with eye tracking and measuring how long it took them to come to decision, the researchers could see how the children gathered information before making a decision.

"We can look at behavior like how they are distributing their looks to find useful information, how they go back and forth between images, or whether they take extra time before responding," Leckey said.

Children spent longer deliberating on more difficult trials, when the images were more similar, and when they came to an incorrect decision. The researchers were able to further analyze the data using a type of model called a drift-diffusion model, never previously used in studies of such young children.

"We can see if they act as if they are more or less confident," she said. Ghetti believes that toddlers' responses to difficult decisions and their search for more information become the basis for eventually becoming aware of our uncertainty, which is fundamental to how we learn as older children and adults.

The need for pacemakers in Africa will rise as life expectancy and associated cardiovascular diseases increase; however, the pacing field, including appropriate training, facilities and devices, are not sufficient to meet future need, according to an Africa Heart Rhythm Association (AFHRA) statement published in the Journal of the American College of Cardiology.

According to the paper, a recent Pan-African Society of Cardiology found that pacemakers are not implanted in about 20% of African countries. In African countries that do perform pacing, sites and trained implanters are few, with 17 countries having fewer than five centers each. The median implantation rate in 2016 in Africa was 2.66%, which is 200-fold lower than Europe.

The statement examines four main barriers to pacing in Africa--lack of skilled implanters, lack of facilities for implantation, high cost of devices and lack of government support--and offers solutions for how to address these barriers. Researchers focus on improving local training and fellowship programs so trainees do not have to leave the continent for specialized instruction, collaborating with local governments to subsidize equipment, and ensuring quality assurance of implanting centers and clinicians through AFHRA oversight.

Preliminary data from researchers at the University of Cincinnati Cancer Center show that immunotherapy doesn't necessarily worsen complications for patients with both COVID-19 and cancer.

This data is being presented by Layne Weatherford, PhD, UC postdoctoral fellow, at the American Association for Cancer Research Virtual Meeting: COVID-19 and Cancer, Monday, July 20.

Weatherford works in the lab of Trisha Wise-Draper, PhD, an associate professor of medicine, Division of Hematology Oncology, at the UC College of Medicine, UC Health oncologist and medical director of the UC Cancer Center Clinical Trials Office.

"Many COVID-19 complications result from an overactive immune response, leading to an increased production of proteins called cytokines," Weatherford says. "Increased production of these proteins can cause issues like respiratory failure. Patients with cancer are more susceptible to COVID-19 infection as well as severe complications from it.

"Many patients with cancer are treated with immunotherapy, which activates the immune system against cancer to destroy it. In patients with both COVID-19 and cancer, our team thought that immunotherapy might increase the immune system response, which could already be overactive because of the COVID-19 infection."

Wise-Draper says researchers thought treating COVID-19 patients with cancer immunotherapy might result in worsening patients' health and overall outcomes.

"We are continuing to investigate whether immunotherapy causes an increased production of these proteins by immune cells from COVID-19 patients, but our initial findings are showing that immunotherapy is not significantly impacting it," she adds.

Researchers are conducting this study using blood samples from patients with cancer taken from the UC COVID-19 biorepository, which Kris Hudock, MD, assistant professor in the Division of Pulmonary, Critical Care and Sleep Medicine at the UC College of Medicine, oversees.

"We are examining how immune checkpoint inhibitors, drugs that allow immune cells to respond more strongly, in combination with other treatments, like chemotherapy or radiation, affect the immune cells of COVID-19 patients and patients with both COVID-19 and cancer," she says.

She and Weatherford add that their preliminary data show that an anti-diabetic drug, metformin, can reduce production of these proteins by immune cells of COVID-19 patients.

"These are promising, initial findings," Wise-Draper says. "Additional research is needed, but our results show that we might be able to treat COVID-19 complications with metformin or a similar drug one day."

A rock core from Petrified Forest National Park, Arizona, has given scientists a powerful new tool to understand how catastrophic events shaped Earth's ecosystems before the rise of the dinosaurs.

The quarter-mile core is from an important part of the Triassic Period when life on Earth endured a series of cataclysmic events: Our planet was struck at least three times by mountain-sized asteroids, chains of volcanoes erupted to choke the sky with greenhouse gases, and tectonic movement tore apart Earth's single supercontinent, Pangea.

Among the chaos, many plants and animals, including some of the long-snouted and armored reptiles that ruled Pangea throughout the Triassic, vanished in a possible shake-up of life on Earth that scientists have yet to explain.

The study, published July 20 in GSA Bulletin, offers scientists a foundation to explain the changes in the fossil record and determine how these events may have shaped life on Earth.

By determining the age of the rock core, researchers were able to piece together a continuous, unbroken stretch of Earth's history from 225 million to 209 million years ago. The timeline offers insight into what has been a geologic dark age and will help scientists investigate abrupt environmental changes from the peak of the Late Triassic and how they affected the plants and animals of the time.

"The core lets us wind the clock back 225 million years when Petrified Forest National Park was a tropical hothouse populated by crocodile-like reptiles and turkey-size early dinosaurs," said Cornelia Rasmussen, a postdoctoral researcher at the University of Texas Institute for Geophysics (UTIG), who led the analysis that determined the age of the core.

"We can now begin to interpret changes in the fossil record, such as whether changes in the plant and animal world at the time were caused by an asteroid impact or rather by slow geographic changes of the supercontinent drifting apart," she said.

Petrified Forest National Park's paleontologist Adam Marsh said that despite a rich collection of fossils from the period in North America, until now there was little information on the Late Triassic's timeline because most of what scientists knew came from studying outcrops of exposed rock pushed to the surface by tectonic movements.

"Outcrops are like broken pieces of a puzzle," said Marsh, who earned his Ph.D. from The University of Texas at Austin's Jackson School of Geosciences. "It is incredibly difficult to piece together a continuous timeline from their exposed and weathered faces."

Marsh was not an author of the study but is part of the larger scientific coring project. UTIG is a unit of the Jackson School.

The Petrified Forest National Park core overcomes the broken puzzle problem by recovering every layer in the order it was deposited. Like tree rings, scientists can then match those layers with the fossil and climate record.

To find the age of each layer, the researchers searched the rock core for tiny crystals of the mineral zircon, which are spewed into the sky during volcanic eruptions. Zircons are a date stamp for the sediments with which they are buried. Researchers then compared the age of the crystals with traces of ancient magnetism stored in the rocks to help develop a precise geologic timeline.

Geoscience is rarely so simple, however, and according to Rasmussen, the analysis of the core gave them two slightly different stories. One shows evidence that a shake-up in the species might not be connected to any single catastrophic event and could simply be part of the ordinary course of gradual evolution. The other shows a possible correlation between the change in the fossil record and a powerful asteroid impact, which left behind a crater in Canada over 62 miles wide.

For Marsh, the different findings are just part of the process to reach the truth.

"The two age models are not problematic and will help guide future studies," he said.

A new study identified 37 recently active volcanic structures on Venus. The study provides some of the best evidence yet that Venus is still a geologically active planet. A research paper on the work, which was conducted by researchers at the University of Maryland and the Institute of Geophysics at ETH Zurich, Switzerland, was published in the journal Nature Geoscience on July 20, 2020.

"This is the first time we are able to point to specific structures and say 'Look, this is not an ancient volcano but one that is active today, dormant perhaps, but not dead,'" said Laurent Montési, a professor of geology at UMD and co-author of the research paper. "This study significantly changes the view of Venus from a mostly inactive planet to one whose interior is still churning and can feed many active volcanoes."

Scientists have known for some time that Venus has a younger surface than planets like Mars and Mercury, which have cold interiors. Evidence of a warm interior and geologic activity dots the surface of the planet in the form of ring-like structures known as coronae, which form when plumes of hot material deep inside the planet rise through the mantle layer and crust. This is similar to the way mantle plumes formed the volcanic Hawaiian Islands.

But it was thought that the coronae on Venus were probably signs of ancient activity, and that Venus had cooled enough to slow geological activity in the planet's interior and harden the crust so much that any warm material from deep inside would not be able to puncture through. In addition, the exact processes by which mantle plumes formed coronae on Venus and the reasons for variation among coronae have been matters for debate.

In the new study, the researchers used numerical models of thermo-mechanic activity beneath the surface of Venus to create high-resolution, 3D simulations of coronae formation. Their simulations provide a more detailed view of the process than ever before.

The results helped Montési and his colleagues identify features that are present only in recently active coronae. The team was then able to match those features to those observed on the surface of Venus, revealing that some of the variation in coronae across the planet represents different stages of geological development. The study provides the first evidence that coronae on Venus are still evolving, indicating that the interior of the planet is still churning.

"The improved degree of realism in these models over previous studies makes it possible to identify several stages in corona evolution and define diagnostic geological features present only at currently active coronae," Montési said. "We are able to tell that at least 37 coronae have been very recently active."

The active coronae on Venus are clustered in a handful of locations, which suggests areas where the planet is most active, providing clues to the workings of the planet's interior. These results may help identify target areas where geologic instruments should be placed on future missions to Venus, such as Europe's EnVision that is scheduled to launch in 2032.

A group of international scientists have substantially lengthened the duration of time that a spin-orbit qubit in silicon can retain quantum information for, opening up a new pathway to make silicon quantum computers more scalable and functional.

Spin-orbit qubits have been investigated for over a decade as an option to scale up the number of qubits in a quantum computer, as they are easy to manipulate and couple over long distances. However, they have always shown very limited coherence times, far too short for quantum technologies.

The research published today in Nature Materials shows that long coherence times are possible when spin-orbit coupling is strong enough. In fact, the scientists demonstrated coherence times 10,000 times longer than previously recorded for spin-orbit qubits, making them an ideal candidate for scaling up silicon quantum computers.

"We turned the conventional wisdom on its head by demonstrating exceptionally long coherence times - ~10 milliseconds - and therefore, that spin-orbit qubits can be remarkably robust," says UNSW Professor Sven Rogge, Chief Investigator, Centre for Quantum Computation and Communication Technology (CQC2T), who led the research team.

Strong coupling is key

How stable a qubit is determines the length of time that it can preserve quantum information for.

In spin-orbit qubits information is stored on the spin of the electron as well as its motion - how it 'orbits' atoms in the lattice of the chip. It is the strength of the coupling between these two spins that keeps the qubit stable and less prone to being destroyed by electric noise in devices.

"The quantum information in most spin-orbit qubits is extremely fragile. Our spin-orbit qubit is special because quantum information stored in it is very robust," says lead author Dr Takashi Kobayashi, who performed the research at UNSW and is now at Tohoku University.

"The information is stored in the orientation of the spin and orbit of the electron, not just the spin. The circular orbit of the charged electron and the spin are locked together like gears due to the very strong attraction in the spin-orbit coupling.

"Increasing the strength of that spin-orbit coupling lets us achieve the significantly longer coherence times we've published today."

Engineering longer coherence times

To increase the coherence time, the researchers first created spin-orbit qubits by introducing impurities, called acceptor dopant atoms, in a silicon crystal. The team then modified the strain in the silicon lattice structure of the chip to generate different levels of spin-orbit coupling.

"The crystal is special because it only contains the isotope of silicon with no nuclear spin. This eliminates magnetic noise, and because it is strained sensitivity to electric noise is also reduced." Says Kobayashi.

"Our chip was fixed on to a material that at a low temperature stretches out the silicon - like a rubber band. Stretching the lattice to the correct tension allowed us to tune the spin-orbit coupling to the optimal value."

The end result produced coherence times over 10,000 times longer than previously found in spin-orbit qubits.

This means quantum information is preserved for much longer, allowing many more operations to be performed - an important stepping-stone for scaling up quantum computers.

Scaling up with spin-orbit coupling

For a quantum computer to outperform a classical computer, a large number of qubits need to work together to perform complex calculations.

"The stability of our spin-orbit qubit to electric fields is unique, proving a robust new pathway to make scalable quantum computers." Says co-author Joe Salfi, who performed the research at CQC2T and is now at the University of British Columbia.

The finding ultimately enables new ways of manipulating individual qubits and coupling qubits over much larger distances, which will make the chip fabrication process more flexible.

The electrical interaction also allows coupling to other quantum systems, opening up the prospects of hybrid quantum systems.

Earlier research published in Science Advances by the UNSW team showed spin-orbit coupling in silicon provides many advantages for scaling up to a large number of qubits.

"Spins in silicon are very attractive for scalable quantum information devices because they're stable and compatible with current computer processing techniques, making those devices easy to manufacture," says Prof. Rogge.

"Now that we've demonstrated long coherence times, spin-orbit qubits make a strong candidate for a large-scale quantum processor in silicon."

In a world first, Monash University researchers have identified a key biomolecule that enhances the repair of your gut lining by prompting stem cells to regenerate damaged tissue.

A strong cellular lining is essential for a healthy gut as it provides a barrier to the billions of microbes and harmful toxins present in our intestinal tract. This barrier is often damaged by infection and inflammation, which causes many painful symptoms.

The study, published in Cell Stem Cell and led by Professor Helen Abud and Dr Thierry Jardé from Monash Biomedicine Discovery Institute, investigated the environment that surrounds gut stem cells and used "mini gut" organoid methodology where tiny replicas of gut tissue were grown in a dish. The study defined key cells that reside in close proximity to stem cells in the gut that produce the biomolecule Neuregulin-1 that acts directly on stem cells to kick-start the repair process.

"Our really important discovery is that supplementation with additional Neuregulin-1 accelerates repair of the gut lining by activation of key growth pathways," Professor Abud said.

"Our findings open new avenues for the development of Neuregulin 1-based therapies for enhancing intestinal repair and supporting rapid restoration of the critical gut function."

Gastrointestinal disease, such as Crohn's disease and ulcerative colitis, is a major health issue worldwide and results in severe damage to the epithelial cell layer lining the gut. Under these conditions, the intestine has a limited capacity to repair efficiently to restore its main absorptive function and is associated with symptoms including diarrhoea, dehydration, loss of weight and malnutrition. Developing ways to support intestinal tissue repair will dramatically improve patient recovery.

"It was very exciting to observe that Neuregulin 1 can not only drive cells to divide but enhances stem cell properties which supercharges these cells into a repair program," Dr Jardé said.

"This shortens the period of damage. The gut lining is injured during common chemotherapy treatment for cancer and we were also able to show recovery is significantly improved with application of Neuregulin-1 following chemotherapy.

Researchers at McGill University have discovered bacterial organelles involved in gene expression, suggesting that bacteria may not be as simple as once thought. This finding could offer new targets for the development of new antibiotics.

The study, published in Proceedings of the National Academy of Sciences, is the first to show that E. coli uses similar strategies to regulate gene transcription as other more complex cell types.

Just like the human body is made up of organs that perform specialized functions, individual cells contain specialized compartments - such as energy-producing mitochondria - called organelles. Complex cells contain many different organelles, most of which are enclosed by a membrane that holds them together. Because bacteria do not have membrane-bound organelles, they were assumed to lack them altogether.

Stephanie Weber, an assistant professor in McGill's Department of Biology, and her team are the first to show that bacteria do in fact have such specialized compartments.

"Our paper provides evidence for a bacterial organelle that is held together by "sticky" proteins rather than a membrane," says Weber, who is the study's senior author.

The bacterial organelles described in the study are formed in a similar fashion to membraneless cellular compartments found in more complex eukaryotic cells (cells with a nucleus) through a process called phase separation, the same phenomenon that causes oil and vinegar to separate in salad dressing.

"This is the first direct evidence of phase separation in bacteria, so it may be a universal process in all cell types, and could even have been involved in the origin of life," explains Weber.

Because of the small size of the bacterial cells they were studying, Weber's team used an imaging technique - photo activated localization microscopy - to track the organelle-forming proteins.

Weber is now trying to understand exactly how the proteins assemble into organelles. Because they're involved in the first steps of gene expression - transcription - she believes they might also be an interesting target for the development of a new generation of antibiotic drugs, which are urgently needed to combat drug resistance.

BUFFALO, N.Y. -- Millions of children fail to reach their developmental potential worldwide, in part due to higher rates of exposure to current and legacy pollutants.

Researchers studying chemical exposures among children in Uruguay turned to an unlikely data collection device as part of a recent study: silicone wristbands.

These wristbands -- the kind many people around the world wear to show their support for a cause or organization -- are extremely effective in capturing certain types of harmful chemicals, and they're easy for children to wear.

Researchers from the University at Buffalo and the Catholic University of Uruguay used the wristbands to examine the extent of chemical exposure among a small group of children in Montevideo, Uruguay. The 6- to 8-year-olds wore the bands for seven days. After analyzing the wristbands, researchers found an average of 13 pollutants in each one collected. Some of the wristbands showed exposure to DDT, a harmful pesticide that has been banned for use in many countries, including the U.S., since the 1970s.

The study, published recently in the journal Science of the Total Environment, is the first to apply silicone wristbands to measure children's exposure to chemicals in a country outside of the U.S. The study was conducted as part of an ongoing research project in Montevideo led by Katarzyna "Kasia" Kordas, PhD, the paper's senior author. Kordas is an associate professor of epidemiology and environmental health in UB's School of Public Health and Health Professions and co-director of UB's Community for Global Health Equity.

The UB RENEW (Research and Education in eNergy, Environment and Water) Institute provided funding for the study.

"One of the key findings from this research is that we still observe industrial and agricultural chemicals that have been banned from production for years and even decades," said Steven C. Travis, the study's first author, who is a PhD student in the Department of Chemistry in UB's College of Arts and Sciences.

"We were also able to find specific differences between chemical exposures of the children in our study compared to children in the U.S., and identify potential reasons for differences in exposure," added Travis, whose major PhD adviser, Diana Aga, Henry Woodburn Professor of Chemistry in UB's College of Arts and Sciences, is a paper co-author.

Silicone wristbands have become a popular method in recent years to measure personal exposures to organic chemicals because they are easy to wear and are a non-invasive sampling method. They also have a greater capacity to hold semi-volatile chemicals, and can capture chemicals for a longer period of time. More than 1,500 chemicals have been sampled using silicone wristbands, Travis said.

Researchers analyzed wristbands in this study for 45 chemicals from among five groups: polychlorinated biphenyls (PCBs), pesticides, polybrominated diphenyl ethers (PBDEs), organophosphorus flame retardants (OPFRs) and novel halogenated flame-retardant chemicals (NHFRs). NHFRs were the only chemical group not detected. Anywhere from eight to 19 chemicals were detected in each of 23 wristbands collected.

"The use of wristbands as a personal sampling device is an excellent alternative for assessing what harmful chemicals are accumulating in children's bodies, rather than the old-fashioned way of collecting blood and measuring the chemical concentrations in the blood," said Aga.

PCBs were found in 19 of the 23 wristbands. The researchers noted that the entry and trade of PCBs wasn't regulated in Uruguay until 2007, and that there were an estimated 40,000 transformers -- a major source of PCBs -- operating in the country in 2006.

The presence of PBDEs was confirmed in 22 out of 23 wristbands. Concentrations of this chemical group, however, were much lower than those found in U.S. studies. That was surprising, according to the researchers.

"With this study, we've been able to link different exposures to certain lifestyle characteristics," Travis said. "For example, we are able to suggest that not having carpets in the home may lead to lower exposure to brominated flame retardants, which were used widely in the production of carpet padding. Also, with the use of other studies, we can uncover differences in exposure based on various modes of transportation."

Eleven wristbands contained all six OPFRs analyzed. Pesticides were also present, including DDT, which was found in 20 wristbands.

"It is very concerning that young children are exposed to multiple chemicals, including those that have been banned in the U.S. because of demonstrated harms to health," said Kordas. "We know that when chemicals occur together in so-called mixtures, they could be more detrimental to children's development than each chemical alone."

Travis added, "This emphasizes that we need to be more careful with the chemicals that we use for industrial and agricultural purposes, since they have the potential to remain in the environment and can affect people over decades."

The formation of four-stranded DNA has been tracked in living human cells, allowing scientists to see how it works, and its possible role in cancer.

DNA usually forms the classic double helix shape discovered in 1953 - two strands wound around each other. Several other structures have been formed in test tubes, but this does not necessarily mean they form within living cells.

Quadruple helix structures, called DNA G-quadruplexes (G4s), have previously been detected in cells. However, the technique used required either killing the cells or using high concentrations of chemical probes to visualise G4 formation, so their actual presence within living cells under normal conditions has not been tracked, until now.

A research team from the University of Cambridge, Imperial College London and Leeds University have invented a fluorescent marker that is able to attach to G4s in living human cells, allowing them to see for the first time how the structure forms and what role it plays in cells.

The study is published today in Nature Chemistry.

Rethinking the biology of DNA

One of the lead researchers Dr Marco Di Antonio, who began the work at the University of Cambridge in the laboratory of Professor Sir Shankar Balasubramanian and now leads a research team in the Department of Chemistry at Imperial, said: "For the first time, we have been able to prove the quadruple helix DNA exists in our cells as a stable structure created by normal cellular processes. This forces us to rethink the biology of DNA. It is a new area of fundamental biology, and could open up new avenues in diagnosis and therapy of diseases like cancer.

"Now we can track G4s in real time in cells we can ask directly what their biological role is. We know it appears to be more prevalent in cancer cells and now we can probe what role it is playing and potentially how to block it, potentially devising new therapies."

The team thinks G4s form in DNA in order to temporarily hold it open and facilitate processes like transcription, where the DNA instructions are read and proteins are made. This is a form of 'gene expression', where part of the genetic code in the DNA is activated.

G4s appear to be associated more often with genes involved in cancer, and are detected in larger numbers within cancer cells. With the ability to now image a single G4 at a time, the team say they could track their role within specific genes and how these express in cancer. This fundamental knowledge could reveal new targets for drugs that interrupt the process.

Natural formation

The team's breakthrough in being able to image single G4s came with a rethink of mechanisms usually used to probe the working of cells. Previously, the team had used antibodies and molecules that could find and attach to the G4s, but these needed very high concentrations of the 'probe' molecule. This meant the probe molecules might be disrupting the DNA and actually causing them to form G4s, instead of detecting them naturally forming.

Dr Aleks Ponjavic, now an academic in the Schools of Physics & Astronomy and Food Science and Nutrition at the University of Leeds, jointly lead the research in the laboratory of Professor Sir David Klenerman and developed the method of visualising the new fluorescent marker with microscopy.

He said: "Scientists need special probes to see molecules within living cells, however these probes can sometimes interact with the object we are trying to see. By using single-molecule microscopy, we can observe probes at 1000-fold lower concentrations than previously used. In this case our probe binds to the G4 for just milliseconds without affecting its stability, which allows us to study G4 behaviour in their natural environment without external influence."

For the new probe, the team used a very 'bright' fluorescent molecule in small amounts that was designed to stick to the G4s very easily. The small amounts meant they couldn't hope to image every G4 in a cell, but could instead identify and track single G4s, allowing them to understand their fundamental biological role without perturbing their overall prevalence and stability in the cell.

The team were able to show that G4s appear to form and dissipate very quickly, suggesting they only form to perform a certain function, and that potentially if they lasted too long they could be toxic to normal cell processes.