Brain

The number of sea turtles spotted along the coasts of the UK and Ireland has declined in recent years, researchers say.

University of Exeter scientists studied records going back more than a century (1910-2018) and found almost 2,000 sea turtles had been sighted, stranded or captured.
Recorded sightings increased dramatically in the 1980s and 1990s - possibly due to more public interest in conservation, and better reporting schemes.
Numbers have dropped since 2000, but the reasons for this are unclear.

"Lots of factors could affect the changing of numbers of sea turtles sighted," said Zara Botterell, of the University of Exeter and Plymouth Marine Laboratory.
"Climate change, prey availability and environmental disasters such as the 2010 Deepwater Horizon oil spill could all influence turtle numbers and behaviour.

"However, sea turtle populations in the North Atlantic are largely stable or increasing, and the apparent decrease may represent reduced reporting rather than fewer turtles in our seas.
One reason for this could be that fewer fishing boats are at sea now than in the past - and fishers are the most likely people to see and report turtles."

The most common turtles spotted off the UK and Ireland are leatherbacks - making up 1,683 of the 1,997 sightings since 1910.
Leatherbacks are thought to be the only sea turtle species that "intentionally" visits these waters, with adults arriving in summer in search of their jellyfish prey.

Meanwhile, juvenile loggerheads (240 since 1910) and Kemp's ridley turtles (61) are more often spotted in winter - likely carried on currents and finding themselves stranded in cold waters.

There are seven sea turtle species in total, and the others are much rarer in UK and Irish waters.
Only 11 green turtle sightings were found in the records (all from 1980 to 2016), while just one hawksbill (Cork, Ireland in 1983) and one olive ridley (Anglesey, Wales in 2016) have been recorded.
The only species never recorded in UK or Irish waters is the flatback, which is only found around Northern Australia, Southern Indonesia and Southern Papua New Guinea.

Most of the recorded sightings of turtles in the UK and Ireland were along western and southern coasts.
Of the 1,997 turtles sighted, 143 were "bycatch" (caught accidentally) in fishing lines, nets and ropes - and the large majority of these were released alive.

The study used the TURTLE database, operated by Marine Environmental Monitoring.

The research team thanked the many members of the public who have reported turtle sightings and strandings, and noted the "pivotal role" of the UK Cetacean Strandings Investigation Programme (CSIP) and Scottish Marine Animal Stranding Scheme (SMASS), funded by UK governments.

"We have been lucky to analyse this unique dataset that exists because Britain and Ireland are a real hotbed of engaged citizen science, where members of the public report their sightings in schemes supported by conservation charities and government bodies," said Professor Brendan Godley, who leads the Exeter Marine research group.

Krill is rapidly gaining popularity. The small shrimp-like organism from the Antarctic is used as fish food in aquaculture and increasingly in dietary supplements and healing ointments. Although the krill catch is regulated, caution is required to avoid endangering the population itself and the species that depend on it, warns a group of krill experts headed by Prof. Dr. Bettina Meyer from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) in the journal Communications Earth & Environment - Nature.

Antarctic Krill, Euphausia superba, is a five-centimetre-long, reddish, shrimp-like animal which at first glance, may not appear as an impressive inhabitant of the Southern Ocean. But krill make up for their small individual sizes with the sheer number of their entire population. There is an estimated 300-500 billion Mt of krill in the Southern Ocean comprised of some hundreds of trillions of individuals. This massive biomass makes krill a key component of the local ecosystem. It is the main food source for many predators from fish, penguins and seabirds to seals and whales.

Humans have also developed an interest in krill over the past decades. Norway, along with Korea, China, Chile, the Ukraine and Japan trawl for krill in the Southern Ocean. But the fishing industry has become more efficient at catching krill using not only traditional fishing nets, but new continuous pumping systems. The demand for krill will likely increase, driven by at least two industries. First the increasing production of carnivorous fish through aquaculture, such as salmon, and the subsequent increase in demand for fish meals and marine byproducts. Second, the increasing demand for high value pharma- and nutraceutical products from krill oil and krill meals, such as wound ointment and krill oil capsules for human use and pet food.

The krill fishery is managed by the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR), which was founded in 1982. This body uses surveys and model calculations to determine how much krill may be caught and where it may be caught. The Atlantic sector of the Southern Ocean has the highest concentration of both krill stocks and fishing fleets. This region alone has a maximum allowable catch of 620,000 tons per year distributed over different fishing areas.

This is only a fraction of krill that are estimated to live in the ocean around Antarctica. CCAMLR had long assumed that the established catch limits would not cause serious damage, but krill experts like Bettina Meyer now see things differently. "The problem is that the catch regulations have, so far, been aimed primarily at protecting the krill eaters," explains the researcher. "Too little attention, has been paid to possible risks for the krill stocks themselves.

This is due to the fact that relatively little is still known about some aspects of the biology of these small crustaceans." Financed by the Federal Ministry of Food and Agriculture (BMEL), Bettina Meyer, her colleague Dr. Ryan Driscoll and her research group are trying to shed more light on this issue. In a new publication, krill experts from around the globe summarize why there are several reasons to worry about the future of this key species.

In brief, krill abundances in some regions fluctuate greatly from year to year. However, the causes of these fluctuations are not yet clear and the current management of krill does not adjust the catch accordingly. Furthermore, it is likely that only a small part of the population, limited to a relatively small area, provide the offspring for the entire Atlantic part of the Southern Ocean. Finally, little is known about where the new generation migrate to in their first year. This means that it is possible that the most important parts of the population, the future parents and their offspring, will be overfished.

In 2019 CCAMLR decided to develop a new krill management system to address these issues. The committee is advised by the "Krill Action Group" under the umbrella of the Scientific Committee of Antarctic Research (SCAR), which was founded in 2018. It currently consists of 46 international members, half of which are established and half early career scientist. "Our goal is to provide CCAMLR with the latest knowledge on the size, distribution and dynamics of krill stocks." explains Bettina Meyer, who heads this expert group.

The future of krill management will require answering lingering question in key areas of krill biology. For example, understanding how krill populations in different regions are connected and how adults and juveniles differ in their location and movement. Also unknown are the environmental conditions responsible for determining good or bad krill years. The Atlantic sector of the Southern Ocean is warming rapidly and so understanding how krill will adapt to climate change is crucial. As for the latter, "CCAMLR's previous models do not take this plasticity into account," explains Bettina Meyer, "But we need to know more about this if we are to be able to predict future changes in the ecosystem."

Bettina Meyer and her colleagues have some concrete ideas about how the missing data can be collected. Since space and availability for scientific expeditions aboard research ships are limited, scientists could rely on the support of the fishing fleets. Together, these fishing vessels have the potential to collect a substantial amount of krill data which can help close critical knowledge gaps.

In addition, new technology may help scientists advance their understanding of krill stocks and their distribution. For example, autonomous underwater gliders, which look like mini gliders with a wingspan of about 1.50 metres, can be equipped with cameras, sensors, and echosounders to search for krill. They can roam the ocean from the surface down to 1000 metres for several months, collecting data on the density and distribution of krill.

Another promising technology are advanced moorings, equipped with arrays of sensors to measure water properties and krill density. These stationary devices can provide important information almost year-round in areas critical to the management of the krill fishery. Even krill predators, the whales, seals or penguins, can be recruited to help using attached camera systems and probes equipped with GPS.

"All of this can provide us with valuable new information for better krill management," says Bettina Meyer who is convinced by this approach. But in order to cover large areas of the Southern Ocean it is important to coordinate these research efforts internationally: "As a lone warrior, nobody can answer the complex questions of krill research."

In his quest to bring ever-faster cameras to the world, Caltech's Lihong Wang has developed technology that can reach blistering speeds of 70 trillion frames per second, fast enough to see light travel. Just like the camera in your cell phone, though, it can only produce flat images.

Now, Wang's lab has gone a step further to create a camera that not only records video at incredibly fast speeds but does so in three dimensions. Wang, Bren Professor of Medical Engineering and Electrical Engineering in the Andrew and Peggy Cherng Department of Medical Engineering, describes the device in a new paper in the journal Nature Communications.

The new camera, which uses the same underlying technology as Wang's other compressed ultrafast photography (CUP) cameras, is capable of taking up to 100 billion frames per second. That is fast enough to take 10 billion pictures, more images than the entire human population of the world, in the time it takes you to blink your eye.

Wang calls the new iteration "single-shot stereo-polarimetric compressed ultrafast photography," or SP-CUP.

In CUP technology, all of the frames of a video are captured in one action without repeating the event. This makes a CUP camera extremely quick (a good cell-phone camera can take 60 frames per second). Wang added a third dimension to this ultrafast imagery by making the camera "see" more like humans do.

When a person looks at the world around them, they perceive that some objects are closer to them, and some objects are farther away. Such depth perception is possible because of our two eyes, each of which observes objects and their surroundings from a slightly different angle. The information from these two images is combined by the brain into a single 3-D image.

The SP-CUP camera works in essentially the same way, Wang says.

"The camera is stereo now," he says. "We have one lens, but it functions as two halves that provide two views with an offset. Two channels mimic our eyes."

Just as our brain does with the signals it receives from our eyes, the computer that runs the SP-CUP camera processes data from these two channels into one three-dimensional movie.

SP-CUP also features another innovation that no human possesses: the ability to see the polarization of light waves.

The polarization of light refers to the direction in which light waves vibrate as they travel. Consider a guitar string. If the string is pulled upwards (say, by a finger) and then released, the string will vibrate vertically. If the finger plucks it sideways, the string will vibrate horizontally. Ordinary light has waves that vibrate in all directions. Polarized light, however, has been altered so that its waves all vibrate in the same direction. This can occur through natural means, such as when light reflects off a surface, or as a result of artificial manipulation, as happens with polarizing filters.

Though our eyes cannot detect the polarization of light directly, the phenomenon has been exploited in a range of applications: from LCD screens to polarized sunglasses and camera lenses in optics to devices that detect hidden stress in materials and the three-dimensional configurations of molecules.

Wang says that the SP-CUP's combination of high-speed three-dimensional imagery and the use of polarization information makes it a powerful tool that may be applicable to a wide variety of scientific problems. In particular, he hopes that it will help researchers better understand the physics of sonoluminescence, a phenomenon in which sound waves create tiny bubbles in water or other liquids. As the bubbles rapidly collapse after their formation, they emit a burst of light.

"Some people consider this one of that greatest mysteries in physics," he says. "When a bubble collapses, its interior reaches such a high temperature that it generates light. The process that makes this happen is very mysterious because it all happens so fast, and we're wondering if our camera can help us figure it out."

FRANKFURT. In 1999, the Egyptian chemist Ahmed Zewail received the Nobel Prize for measuring the speed at which molecules change their shape. He founded femtochemistry using ultrashort laser flashes: the formation and breakup of chemical bonds occurs in the realm of femtoseconds. A femtosecond equals 0.000000000000001 seconds, or 10 exp -15 seconds.

Now atomic physicists at Goethe University in Professor Reinhard Dörner's team have for the first time studied a process that is shorter than femtoseconds by magnitudes. They measured how long it takes for a photon to cross a hydrogen molecule: about 247 zeptoseconds for the average bond length of the molecule. This is the shortest timespan that has been successfully measured to date.

The scientists carried out the time measurement on a hydrogen molecule (H2) which they irradiated with X-rays from the synchrotron lightsource PETRA III at the Hamburg accelerator centre DESY. The researchers set the energy of the X-rays so that one photon was sufficient to eject both electrons out of the hydrogen molecule.

Electrons behave like particles and waves simultaneously, and therefore the ejection of the first electron resulted in electron waves launched first in the one, and then in the second hydrogen molecule atom in quick succession, with the waves merging.

The photon behaved here much like a flat pebble that is skimmed twice across the water: when a wave trough meets a wave crest, the waves of the first and second water contact cancel each other, resulting in what is called an interference pattern.

The scientists measured the interference pattern of the first ejected electron using the COLTRIMS reaction microscope, an apparatus that Dörner helped develop and which makes ultrafast reaction processes in atoms and molecules visible. Simultaneously with the interference pattern, the COLTRIMS reactions microscope also allowed the determination of the orientation of the hydrogen molecule. The researchers here took advantage of the fact that the second electron also left the hydrogen molecule, so that the remaining hydrogen nuclei flew apart and were detected.

"Since we knew the spatial orientation of the hydrogen molecule, we used the interference of the two electron waves to precisely calculate when the photon reached the first and when it reached the second hydrogen atom," explains Sven Grundmann whose doctoral dissertation forms the basis of the scientific article in Science. "And this is up to 247 zeptoseconds, depending on how far apart in the molecule the two atoms were from the perspective of light."

Professor Reinhard Dörner adds: "We observed for the first time that the electron shell in a molecule does not react to light everywhere at the same time. The time delay occurs because information within the molecule only spreads at the speed of light. With this finding we have extended our COLTRIMS technology to another application."

Oncotarget Volume 11, Issue 29 reported that In multivariate analyses, serum albumin, GNRI, pathological tumor-node-metastasis stage, and tumor differentiation were independent prognostic factors for CSS.

In pTNM stage I, multivariate analysis identified C-reactive protein and GNRI as independent prognostic factors for CSS.

In univariate analyses in pTNM stages II and III, only low GNRI and low serum albumin levels, respectively, were significantly associated with worse CSS.

In patients with low GNRI, CSS was significantly worse than in those with normal GNRI, especially in pTNM stages I and II groups, but not in stage III group.

Preoperative GNRI may sort patients into low- or high-risk groups for shorter CSS, especially in those with pTNM stage I and II ESCC.

Dr. Noriyuki Hirahara from The Shimane University Faculty of Medicine said, "Patients with advanced esophageal cancer presenting with dysphagia often experience malnutrition as well as impairment of performance status and quality of life."

Serum albumin is a clinically relevant indicator of nutritional status, such as malnutrition and cachexia.

Recently, it has been widely accepted that the GNRI was strongly associated with mortality in elderly hospitalized patients and in patients with various cancers.

However, to the best of the authors knowledge, there have been few reports on the prognostic significance of the GNRI in patients with esophageal squamous cell carcinoma.

In this study, they have investigated whether the GNRI is a useful predictor of long-term survivals in patients with ESCC who underwent a curative esophagectomy.

"In this study, they have investigated whether the GNRI is a useful predictor of long-term survivals in patients with ESCC who underwent a curative esophagectomy"

The Hirahara Research Team concluded in their Oncotarget Research Paper that, "preoperative GNRI can be used to sort patients into groups at high- or low-risk for shorter CSS after undergoing curative resection for ESCC, especially those with pTNM stage I and II ESCC; the interpretation should be done with care due to the differences in clinical background. Therefore, multicenter prospective validation of our findings is considered necessary to confirm the usefulness of GNRI as clinical therapeutic stratification marker for patients requiring more aggressive multimodality treatment or stringing surveillance.

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DOI - https://doi.org/10.18632/oncotarget.27670

Full text - https://www.oncotarget.com/article/27670/text/

Correspondence to - Noriyuki Hirahara - norinorihirahara@yahoo.co.jp

Keywords -
geriatric nutritional risk index,
esophageal squamous cell carcinoma,
curative esophagectomy,
cancer-specific survival,
pathological tumor-node-metastasis

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Journal

Oncotarget

DOI

10.18632/oncotarget.27670

Palo Alto, CA-- In a changing climate, understanding how organisms respond to stress conditions is increasingly important. New work led by Carnegie's Arthur Grossman and Emanuel Sanz-Luque could enable scientists to engineer the metabolism of organisms to be more resilient and productive in a range of environments.

Their research focuses on polyphosphate, an energy-rich polymer of tens to hundreds phosphate groups which is conserved in all kingdoms of life and is integral to many cellular activities, including an organism's ability to respond to changing environmental conditions.

"The ways in which polyphosphate synthesis and mobilization can be integrated into a myriad of biological processes in a range of photosynthetic and non-photosynthetic organisms and various cell types has been difficult to unravel," Grossman said. "Polyphosphate plays a critical role in responding to environmental stresses, including high temperatures, exposure to toxic metals and, of particular interest to us, nutrient deprivation."

The research team--which also included Carnegie's Shai Saroussi, Weichao Huang, and Nicholas Akkawi--investigated how the photosynthetic alga Chlamydomonas reinhardtii copes with a sparsity of nutrients. Their findings were recently published in Science Advances.

The team revealed that polyphosphate synthesis is deeply integrated with cellular metabolism, leveraging this relationship to shape the alga's ability to adapt to challenges in its surroundings.

Using advanced techniques, the researchers showed that the synthesis of polyphosphate is crucial for maintaining the optimal energy balance, enabling cellular physiological processes. When nutrient availability is low, polyphosphate synthesis is necessary for the alga to adjust its cellular metabolism and survive the adverse conditions. It does this by impacting the biochemical processes occurring in the cell's power centers--mitochondria which perform respiration and chloroplasts which perform photosynthesis.

If a cell's ability to synthesize polyphosphate is impaired, it is unable to accomplish normal electron transport in the mitochondria and chloroplasts--central to the functions of these key organelles--compromising cellular regulation, fitness, and survival.

"It is possible that the role of polyphosphate synthesis and mobilization in regulating the energetic functions of the cell under nutrient-limited conditions results in the creation of 'checkpoint' molecules within chloroplast and mitochondria that guide changes in the genes expressed in response to the environmental conditions," said lead author Sanz-Luque.

This knowledge could potentially be harnessed to improve the resilience of other photosynthetic organisms and make them better able to survive the stress of a changing climate.

Together Carnegie's Emanuel Sanz-Luque, Devaki Bhaya, and Arthur Grossman also published a comprehensive review in Frontiers in Plant Science detailing the ways in which polyphosphate integrate into the metabolic networks and regulatory processes in a variety of photosynthetic organisms.

While much attention has been paid to the increasing prevalence of autism spectrum disorder (ASD) among U.S. children and adolescents, less is known about the population of adults with ASD. Medicaid is an important health care coverage provider for individuals with autism, including adults. Using administrative data from the Medicaid Analytic eXtract (MAX), researchers from Drexel University's A.J. Drexel Autism Institute found a substantial increase in the percent of adults receiving services for autism in the Medicaid population from 2008-2012.

"An increasing number of adults will be relying on Medicaid, often through home and community-based services waiver programs, for key services, such as support for community integration and for maintaining employment, into the future," said Whitney Schott, PhD, an assistant researcher professor in the Autism Institute and lead author on the study.

There was higher prevalence of ASD among younger adults (ages 18-24) over the 2008-2012 time period than other adults. Prevalence was lowest among older adults (ages 41-64).

"These results underline the importance of identifying effective and efficient service delivery models within Medicaid to serve the growing number of adults with ASD," said Schott.

Researchers examined Medicaid administrative claims data from 2008-2012, including the population of adults with autism as well as a random sample of adults without autism, in order to identify the administrative prevalence of autism by age category. They looked at individuals that were enrolled in Medicaid for at least nine out of 12 months per year, in order to get a better sense of true administrative prevalence.

"Little is known about the age composition of the adult population with autism," said Schott. "Our research provides key information about the distribution of autism across adult ages over the period 2008-2012, showing that prevalence is higher and growing more quickly among younger adults (ages 18-24) compared to older adults."

She added as more and more youth with autism age into adulthood, many will rely on Medicaid for continued services to integrate into the community, workplace and economy. State Medicaid programs and other insurance providers would be interested in learning more about the age distribution of the adult population with autism enrolled in Medicaid to better serve them.

CAMBRIDGE, MA -- Machine learning is a computational tool used by many biologists to analyze huge amounts of data, helping them to identify potential new drugs. MIT researchers have now incorporated a new feature into these types of machine-learning algorithms, improving their prediction-making ability.

Using this new approach, which allows computer models to account for uncertainty in the data they're analyzing, the MIT team identified several promising compounds that target a protein required by the bacteria that cause tuberculosis.

This method, which has previously been used by computer scientists but has not taken off in biology, could also prove useful in protein design and many other fields of biology, says Bonnie Berger, the Simons Professor of Mathematics and head of the Computation and Biology group in MIT's Computer Science and Artificial Intelligence Laboratory (CSAIL).

"This technique is part of a known subfield of machine learning, but people have not brought it to biology," Berger says. "This is a paradigm shift, and is absolutely how biological exploration should be done."

Berger and Bryan Bryson, an assistant professor of biological engineering at MIT and a member of the Ragon Institute of MGH, MIT, and Harvard, are the senior authors of the study, which appears today in Cell Systems. MIT graduate student Brian Hie is the paper's lead author.

Better predictions

Machine learning is a type of computer modeling in which an algorithm learns to make predictions based on data that it has already seen. In recent years, biologists have begun using machine learning to scour huge databases of potential drug compounds to find molecules that interact with particular targets.

One limitation of this method is that while the algorithms perform well when the data they're analyzing are similar to the data they were trained on, they're not very good at evaluating molecules that are very different from the ones they have already seen.

To overcome that, the researchers used a technique called Gaussian process to assign uncertainty values to the data that the algorithms are trained on. That way, when the models are analyzing the training data, they also take into account how reliable those predictions are.

For example, if the data going into the model predict how strongly a particular molecule binds to a target protein, as well as the uncertainty of those predictions, the model can use that information to make predictions for protein-target interactions that it hasn't seen before. The model also estimates the certainty of its own predictions. When analyzing new data, the model's predictions may have lower certainty for molecules that are very different from the training data. Researchers can use that information to help them decide which molecules to test experimentally.

Another advantage of this approach is that the algorithm requires only a small amount of training data. In this study, the MIT team trained the model with a dataset of 72 small molecules and their interactions with more than 400 proteins called protein kinases. They were then able to use this algorithm to analyze nearly 11,000 small molecules, which they took from the ZINC database, a publicly available repository that contains millions of chemical compounds. Many of these molecules were very different from those in the training data.

Using this approach, the researchers were able to identify molecules with very strong predicted binding affinities for the protein kinases they put into the model. These included three human kinases, as well as one kinase found in Mycobacterium tuberculosis. That kinase, PknB, is critical for the bacteria to survive, but is not targeted by any frontline TB antibiotics.

The researchers then experimentally tested some of their top hits to see how well they actually bind to their targets, and found that the model's predictions were very accurate. Among the molecules that the model assigned the highest certainty, about 90 percent proved to be true hits -- much higher than the 30 to 40 percent hit rate of existing machine learning models used for drug screens.

The researchers also used the same training data to train a traditional machine-learning algorithm, which does not incorporate uncertainty, and then had it analyze the same 11,000 molecule library. "Without uncertainty, the model just gets horribly confused and it proposes very weird chemical structures as interacting with the kinases," Hie says.

The researchers then took some of their most promising PknB inhibitors and tested them against Mycobacterium tuberculosis grown in bacterial culture media, and found that they inhibited bacterial growth. The inhibitors also worked in human immune cells infected with the bacterium.

A good starting point

Another important element of this approach is that once the researchers get additional experimental data, they can add it to the model and retrain it, further improving the predictions. Even a small amount of data can help the model get better, the researchers say.

"You don't really need very large data sets on each iteration," Hie says. "You can just retrain the model with maybe 10 new examples, which is something that a biologist can easily generate."

This study is the first in many years to propose new molecules that can target PknB, and should give drug developers a good starting point to try to develop drugs that target the kinase, Bryson says. "We've now provided them with some new leads beyond what has been already published," he says.

The researchers also showed that they could use this same type of machine learning to boost the fluorescent output of a green fluorescent protein, which is commonly used to label molecules inside living cells. It could also be applied to many other types of biological studies, says Berger, who is now using it to analyze mutations that drive tumor development.

Scientists in Australia have stumbled across an unusual way to observe colour that had previously gone unnoticed.

To create the effect, researchers attached a very thin film of one material to another, larger sample. The electric field (an invisible force created by the attraction and repulsion of electrical charges) is very strong where the two materials are connected.

When combined with 'optical interference' (the interaction of different waves of light), a scattering process occurs from the surface of the material, creating bright colours when viewed under different lighting conditions.

The findings, which have been published in the journal Advanced Optical Materials, have expanded our understanding of the behaviour and properties of light, and could also have practical applications in sensing technology and security devices.

Most materials in the world around us appear a certain colour because they only absorb part of solar spectrum. For example, leaves on a tree look green to us because they absorb red and blue light.

However, some objects, animals and materials create colour a different way, because of the properties they contain. These are known as structural colours.

Structural colours are usually created by diffraction, which happens when rays of light interfere with each other as they reflect off surfaces. Rainbows and colourful oil slicks on top of water are examples of structural colour, and the effect is also responsible for the amazing vivid hues of peacock feathers and butterfly wings.

While those phenomena are well established, an unexpected new mechanism for creating similar effects has been uncovered.

The effect is an example of structural colour forming because of frequency-selective scattering of light, in which the strength of the electric field and the type of material used is a key factor.

Dr Eser Akinoglu of the ARC Centre of Excellence in Exciton Science was using a light microscope to observe gold nanoparticles when he unexpectedly noticed that the entire sample was creating a vivid colour visible to the naked eye from all directions.

Eser asked for help from colleagues at The University of Melbourne, CSIRO, South China Normal University and the University of Bayreuth to explain the mystery.

To understand it properly, they created thin films which could scatter light and at the same time create diffraction or interference. The system was made using silicon nitride coatings on larger metallic aluminium samples.

Different colours were visible by changing the lighting conditions. Under normal light, the samples looked like a mirror, reflecting back almost all visible light. But turning the overhead lights off and using only one beam of light to illuminate the sample produces vivid, iridescent colours.

Explaining how to easily observe this phenomenon, Eser said: "If you use a flashlight, while in a dark room, to illuminate the sample, the reflected light beam travels away from you to the other side of the room.

"The reflected light never reaches your eyes, only the scattered light can reach your eyes. Whereas when the room light is on, light comes from everywhere on to the sample and therefore you will always see reflected light travelling into your eyes.

"The effect is a previously completely unrecognized curiosity that results in us seeing colour. It's fundamentally something different."

Regular cannabis exposure in rats during pregnancy may cause their offspring to have long-term cognitive deficiencies, asocial behavior, and anxiety later in adulthood.

That's according to a new study by neuroscientists in Washington State University's Integrative Physiology and Neuroscience unit that provides a rare look at the effects of using cannabis during pregnancy.

"The reality of cannabis research is there's not a lot of it," said Halle Weimar, first author on the paper and graduate student in the neuroscience program. "This research helps get information out to women so they can make an educated decision that is best for them."

Weimar and her colleagues found the offspring of pregnant rats exposed to cannabis vapor were more likely to make regressive errors after they were trained new methods to receive sugar pellets. They were also less social and more anxious when placed in new environments.

Weimar said the research is especially significant as recreational and medicinal cannabis use continues to increase among pregnant women as well as the general population.

The study, recently published in the journal Neuropharmacology, utilized a first-of-its-kind e-cigarette technology to deliver cannabis vapor to pregnant female rats before and throughout their entire gestation period.

"The idea was to use a more clinically relevant model to mirror how humans use cannabis, specifically how pregnant women use cannabis," Weimar said.

Researchers also delivered propylene glycol vegetable glycerol mixture, commonly found in vape juice, to explore its effects in rats. A control group was left in their home cage and not exposed to any vapor.

Vapor was administered twice daily to rats in one-hour sessions during mating and pregnancy.

The research team found significant behavioral changes and cognitive deficits that persisted into adulthood in the offspring of the pregnant rats exposed to cannabis.

Using different levers and a cue light, researchers trained and rewarded rats with sugar pellets for pressing a lever paired with the cue light. The rats were then required to change their strategy during test day and instead ignore the cue, which was used as a measure of cognitive flexibility.

"While rats eventually caught on, those whose mothers were exposed to cannabis were more likely to revert to the old pattern and make regressive errors," Weimar said. "They also took more trials to learn the rules."

Male and female juvenile rats whose mothers were exposed to cannabis also engaged in far fewer play behaviors. The male rats were especially hesitant to engage with other rats in their initial social introductions.

Moreover, adult rats whose mothers were exposed to cannabis exhibited anxiety-like behavior in new environments.When placed in a large, elevated maze with open and closed arms, the rats were more likely to stay in the closed arms of the maze and explore the open, exposed arms less.

"They tend to feel safer in closed arms as opposed to rats that are less anxious and willing to venture into open spaces and take more risks," Weimar said.

She said the finding is significant because it shows cannabis vapor administered to a rat during pregnancy may cause its offspring to have age-dependent effects well into adulthood, noting the observation wasn't noted in rats when they were juveniles.

The researchers noticed changes in the rats' behavior as pups as well.

Weimar said rats whose mothers were exposed to cannabis made more than 100 more ultrasonic vocalizations, or cries for their mother, compared to the control group, days after birth.

"It's pretty noteworthy because this is one of the only tests you can do that looks at emotional reactivity in neonates and they were far more reactive than the other groups," Weimar said.

Some of the world's largest specimens of rare calcium carbonate crystals known as glendonites are found in Denmark.

The crystals were formed between 56 and 54 million of years ago, during a period known to have had some of the highest temperatures in Earth's geologic history. Their presence has long stirred wonder among researchers the world over.

"Why we find glendonites from a hot period, when temperatures averaged above 35 degrees, has long been a mystery. It shouldn't be possible," explains Nicolas Thibault, an associate professor at the University of Copenhagen's Department of Geosciences and Natural Resource Management.

This is because glendonites are composed of ikaite, a mineral that is only stable, and can therefore only crystallize, at temperatures of less than four degrees Celsius.

Volcanoes responsible for cold intervals

In their new study, Nicolas Thibault, along with department colleagues Madeleine Vickers, Christian Bjerrum and Christoph Korte, performed chemical analyses of the Danish glendonites.

Their work reveals that the early Eocene Epoch, between 56 and 48 million years ago, was not at all as uniformly warm as once thought.

"Our study proves that there must have been periods of cold during the Eocene Epoch. Otherwise, these crystals couldn't exist -- they would have simply melted. We also propose a suggestion for how this cooling might have happened, and in doing so, potentially solve the mystery of how glendonites in Denmark and the rest of the world came to be," says Nicolas Thibault. He adds:

"There were probably a large number of volcanic eruptions in Greenland, Iceland and Ireland during this period. These released sulphuric acid droplets into the stratosphere, which could have remained there for years, shading the planet from the sun and reflecting sunlight away. This helps to explain how regionally cold areas were possible, which is what affected the climate in early Eocene Denmark."

Layers of volcanic ash in rock

The presence of volcanic activity is revealed by, among other things, sedimentary layers visible on Fur, where layers of volcanic ash are clearly visible as bands in the coastal bluffs.

"Our study helps solve a mystery about glendonites, as well as demonstrating that cooler episodes are possible during otherwise warmer climates. The same can be said for today, as we wise up to the possibility of abrupt climate change," concludes Nicolas Thibault.

Caterpillars are small bugs with two rows of tiny legs that all move in a coordinated manner, causing the caterpillar to almost glide across a leaf. Mycoplasma pneumoniae, the bacterium behind many cases of pneumonia in human communities, moves in a similar fashion around our body's cells.

Using a lock and key attachment method, the yellow bowling pin shaped M. pneumonia (see left-hand object in the image) uses tiny microscopic appendages (the red dots) to attach itself to the surface of a cell and move around, altering itself to avoid detection from our immune system. In the 80's, scientists discovered a protein complex at the end of this appendage to be at the center of M. pneumoniae's ability to attach, move, and change. Called "Nap", this protein complex acts as a "key" that locks onto a sugary substance found all over the surface of our cells made up of sialic acid oligosaccharides. Understanding this "Nap" structure could lead to treatments that inhibit this locking mechanism, allowing for the production of medicine and vaccines that could put an end to the bacterium's ability to attach, move, change, and ultimately infect.

However, its unraveling had eluded the scientific community for more than 40 years - until now, when a team of researchers from 3 countries, including Japanese teams led by Professor Makoto Miyata of the Graduate School of Science, Osaka City University, clarified it at the atomic level.

The results of the research have been published in the October edition of the online scientific journal "Nature Communications".

By isolating the proteins P1 and P40/P90 that make up the "Nap" structure and examining each one through a combination of X-ray crystallography and cryo-electron microscopy, "we found that the shape of the structure resembles four corndogs bundled at the stick and stuck into the membrane of M. pneumonia", explains Prof. Miyata. (the "Nap" structure is on the right-hand side of the image.) "Also, contrary to popular belief, we found it was the proteins P40/P90, not P1, that bind to the sialic acid substance found on our cell tissue."

"This is one of many big revelations to come, including how the bacterium avoids our immune system, now that the architecture of the "Nap" protein complex has been revealed," exclaims the professor.

ITHACA, N.Y. - Hungry giant predators, treacherous mud and a tired, probably cranky toddler - more than 10,000 years ago, that was the stuff of every parent's nightmare.

Evidence of that type of frightening trek was recently uncovered, and at nearly a mile it is the longest known trackway of early-human footprints ever found.

The discovery shows the archaeological findings of footprint tracks at White Sands National Park in New Mexico. The tracks run for 1.5 kilometers (.93 miles) and show a single set of footprints that are joined, at point, by the footprints of a toddler. The paper's authors have shown how the footprint tracks, as well as the distinctive shapes they left, show a woman (or possibly an adolescent male) carrying a toddler in their arms, shifting the toddler from left to right, and occasionally putting the child down.

"When I first saw the intermittent toddler footprints, a familiar scene came to mind," said Thomas Urban, research scientist at Cornell University. Urban has pioneered the application of geophysical imaging to detect footprints.

The tracks were found in a dried-up lakebed, which contains a range of other footprints dating from 11,550 to 13,000 years ago. The lakebed's formerly muddy surface preserved footprints for thousands of years as it dried up.

Previously found in the terrain are the prints of animals such as mammoths, giant sloths, saber-toothed cats and dire wolves. Sloths and mammoths were found to have intersected the human tracks after they were made, showing that this terrain hosted both humans and large animals at the same time, making the journey taken by this individual and child a dangerous one.

The recently discovered footprints were noted for the straightness, as well as being repeated a few hours later on a return journey - only this time without a child in tow, which can be seen from the tracks.

"This research is important in helping us understand our human ancestors, how they lived, their similarities and differences," said co-author Sally Reynold, senior lecturer in hominin paleoecology at Bournemouth University. "We can put ourselves in the shoes, or footprints, of this person (and) imagine what it was like to carry a child from arm to arm as we walk across tough terrain surrounded by potentially dangerous animals."

Extracellular vesicles (EVs) -- nanometer sized messengers that travel between cells to deliver cues and cargo -- are promising tools for the next generation of therapies for everything from autoimmune and neurodegenerative diseases to cancer and tissue injury. EVs derived from stem cells have already been shown to help heart cells recover after a heart attack, but exactly how they help and whether the beneficial effect is specific to EVs derived from stem cells has remained a mystery.

Now, researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) have unraveled potential mechanisms behind the healing power of EVs and demonstrated their capacity to not only revive cells after a heart attack but keep cells functioning while deprived of oxygen during a heart attack. The researchers demonstrated this functionality in human tissue using a heart-on-a-chip with embedded sensors that continuously tracked the contractions of the tissue.

The team also demonstrated that these intercellular travelers could be derived from endothelial cells, which line the surface of blood vessels and are more abundant and easier to maintain than stem cells.

The research is published in Science Translational Medicine.

"Our organ-on-chip technology has progressed to the point where we can now fight drug targets instead of fighting the chip design," said Kit Parker, the Tarr Family Professor of Bioengineering and Applied Physics at SEAS and senior author of the study. "With this study, we have mimicked a human disease on a chip with human cells and developed a novel therapeutic approach to treat it."

Heart attacks, or myocardial infarctions, occur when blood flow to the heart is blocked. Of course, the best way to treat a heart attack is to restore blood flow but that process actually may cause more damage to the cells in the heart. So-called ischemia-reperfusion injury (IRI) or reoxygenation injury, happens when blood supply returns to tissue after a period of lack of oxygen.

"The cellular response to IRI involves multiple mechanisms, such as calcium and proton overload, oxidative stress, mitochondrial dysfunction and more," said Moran Yadid, a postdoctoral fellow at SEAS and The Wyss Institute for Biologically Inspired Engineering and first author of the paper. "This complex set of processes poses a challenge for the development of effective therapies that can address each of these problems."

That's where the endothelial-derived EVs (EEVs) come in. Because these vesicles are derived from vascular tissue, which is uniquely tuned to sense hypoxic stress, the researchers hypothesized that the cargo they carry could provide direct protection to cardiac muscle.

The researchers mapped the entire set of EEV proteins that are, or can be, expressed by the vesicles.

"Surprisingly, even though these vesicles are only a hundred and fifty nanometers in diameter, they contain almost 2,000 different proteins," said Yadid. "A lot of these proteins relate to metabolic processes like respiration, mitochondrial function, signaling and homeostasis. In other words, a lot of processes that relate to the cardiac response to stress. So, rather than one molecule that is therapeutic, we think that the exosomes contain a cocktail of molecules and proteins that can, all together, help the cell maintain homeostasis, deal with the stress, modify metabolic action and reduce the amount of injury."

The team tested the effect of EEVs on human heart tissue using the heart-on-a-chip model developed by the Disease Biophysics Group at SEAS. Organ-on-chip platforms mimic the structure and function of native tissue and allow researchers to observe, in real time, the effects of injuries and treatments in human tissue. Here, the researchers simulated a myocardial infarction and reoxygenation on chips that were infused with EEVs and those that were not.

The researchers found that in tissues treated with EEVs, the cardiomyocytes could better adapt to stress conditions and sustain a higher workload. The researchers induced injury by three hours of oxygen restrictions followed by 90 minutes of reoxygenation and then measured the fraction of dead cells and the contractile force of the tissue. The heart tissue treated with EEVs had half as many dead cells and had a contractile force four times higher than the untreated tissue after injury.

The team also found that injured cardiomyocytes that had been treated with EEVs exhibited a set of proteins that was more similar to the uninjured ones compared with untreated cells. Surprisingly, the team also observed that cells treated with EEVs continued to contract even without oxygen.

"Our findings indicate that EEVs could protect cardiac tissue from reoxygenation injury in part by supplementing the injured cells with proteins and signaling molecules that support different metabolic processes, paving the way for new therapeutic approaches," said André G. Kléber, a Visiting Professor of Pathology at Harvard Medical School and co-author of the study.

"Exosomal cell therapies might be beneficial when the traditional model of one molecule, one target just won't cure the disease," said Parker. "With the vesicles we administered, we believe we are taking a shotgun approach to hitting a network of drug targets. With our organ on chip platform, we will be poised to use synthetic exosomes in therapeutic manner that may be more efficient and amenable to more reliable manufacturing."

What The Study Did: Researchers examined the association between use of e-cigarettes and self-reported wheezing among adolescents ages 12 to 17.

Authors: Alayna P. Tackett, Ph.D., of the University of Southern California in Los Angeles, is the corresponding author.

To access the embargoed study: Visit our For The Media website at this link https://media.jamanetwork.com/

(doi:10.1001/jamanetworkopen.2020.20671)

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, conflict of interest and financial disclosures, and funding and support.