Tech

A research team at KAIST reported clinically accurate multiplexed electrical biosensor for detecting Alzheimer's disease by measuring its core biomarkers using densely aligned carbon nanotubes.

Alzheimer's disease is the most prevalent neurodegenerative disorder, affecting one in ten aged over 65 years. Early diagnosis can reduce the risk of suffering the disease by one-third, according to recent reports. However, its early diagnosis remains challenging due to the low accuracy but high cost of diagnosis.

Research team led by Professors Chan Beum Park and Steve Park described an ultrasensitive detection of multiple Alzheimer's disease core biomarker in human plasma. The team have designed the sensor array by employing a densely aligned single-walled carbon nanotube thin films as a transducer.

The representative biomarkers of Alzheimer's disease are beta-amyloid42, beta-amyloid40, total tau protein, phosphorylated tau protein and the concentrations of these biomarkers in human plasma are directly correlated with the pathology of Alzheimer's disease.

The research team developed a highly sensitive resistive biosensor based on densely aligned carbon nanotubes fabricated by Langmuir-Blodgett method with a low manufacturing cost.

Aligned carbon nanotubes with high density minimizes the tube-to-tube junction resistance compared with randomly distributed carbon nanotubes, which leads to the improvement of sensor sensitivity. To be more specific, this resistive sensor with densely aligned carbon nanotubes exhibits a sensitivity over 100 times higher than that of conventional carbon nanotube-based biosensors.

By measuring the concentrations of four Alzheimer's disease biomarkers simultaneously Alzheimer patients can be discriminated from health controls with an average sensitivity of 90.0%, a selectivity of 90.0% and an average accuracy of 88.6%.

This work, titled "Clinically accurate diagnosis of Alzheimer's disease via multiplexed sensing of core biomarkers in human plasma", were published in Nature Communications on January 8th 2020. The authors include PhD candidate Kayoung Kim and MS candidate Min-Ji Kim.

Professor Steve Park said, "This study was conducted on patients who are already confirmed with Alzheimer's Disease. For further use in practical setting, it is necessary to test the patients with mild cognitive impairment." He also emphasized that, "It is essential to establish a nationwide infrastructure, such as mild cognitive impairment cohort study and a dementia cohort study. This would enable the establishment of world-wide research network, and will help various private and public institutions."

When we predict future climate, it is important to understand the climate of the past. We do. Mostly. Some details are still debatable.

An example of that are the periodicities of ice ages - that is, how ice ages come and go. This is described in a theory developed by amongst others the astronomer Milankovitch in the 1920ies. The theory describes mathematically how incoming radiation from the sun varies over time because the orbit of the Earth around the sun is elliptical and our dear planet wobbles like a top.

All in all these small differences lead to continuous changes in the amount of light and heat that reaches the poles in a 40.000 year cycle and thus forces the climate in and out of ice ages and interglacials.

Ice ages hard to predict

The theory is good, but it doesn't explain everything. The periodicity of ice ages has not been as precise as the theory would indicate. Why is that? Is it because of noise in the system - that is coincidences, that overshadow the general mechanism, or are the inconsistencies due to problems with the model? The question has long been debated.

Now climate scientist from the TiPES project, Peter Ditlevsen from Physics of Ice, Climate and Earth at the Niels Bohr Institute, University of Copenhagen and colleagues Takahito Mitsui from the University of Tokyo and Michel Crucifix from UCLouvan in Belgium argue that coincidences play a large part.

In their paper, "Crossover and peaks in the Pleistocene climate spectrum; understanding from simple ice age models", published today in the journal Climate Dynamics, they document that the climate system is more chaotic than the model indicates. A myriad of coincidences seem to displace the ice ages from the predictions of the theory.

The influence of coincidence

In other words - the theory is good, but a large amount of noise can partly overrule the effect of the astronomical variations.

It is an analysis of the so called climate spectrum that has led to this conclusion. The climate spectrum is calculated from observed fluctuations in climate of the past. It shows how a range of different processes influence the climate - rising and falling amounts of CO2, rising and falling amounts of energy from the sun, rising and falling amounts of geological activity and so on.

Some of these changes come and go in short time spans others fluctuate over longer periods. That is, some have a high frequency, others a lower frequency. Together they explain the variation, the climate has endured over millions of years.

In the new analysis the climate spectrum is compared to expectations from different models of ice age variations. The analysis shows that the climate indeed is the result of a range of such underlying periodic processes but also of a large amount of background noise which is not periodic. That means coincidences play a large role in changes of the climate.

Tipping points might also be harder to predict

- With this result we can better understand, how ice ages come and go. But we also see, that the climate system can react abruptly and unpredictably to external influences like our current emmissions of carbon dioxide. That means it might be hard to calculate if - or when we reach a tipping point in the climate system. And we should maybe apply a more conservative risk assesment then the one IPCC recommends, says Peter Ditlevsen.

If a tipping point is reached the Earth system will change irreversibly into another state.

Men who are taller in young adulthood, as an indicator of early-life circumstances, may have a lower risk of dementia in old age, suggests a study published today in eLife.

Finding ways to identify individuals at risk of dementia is essential. It can help people take preventive measures or plan for their future care. The study, originally posted on bioRxiv*, indicates that young adult height might be one potential risk factor to consider.

Previous studies have suggested that height may be a risk factor for dementia, but much of this research was not able to take into account genetic, environmental, or other early-life factors that may be linked to both height and dementia.

"We wanted to see if body height in young men is associated with diagnosis of dementia, while exploring whether intelligence test scores, educational level, and underlying environmental and genetic factors shared by brothers explain the relationship," says lead author Terese Sara Høj Jørgensen, Assistant Professor at the Section of Social Medicine, Department of Public Health, University of Copenhagen, in Denmark.

To do this, Jørgensen and her colleagues analysed data on 666,333 Danish men born between 1939 and 1959, including 70,608 brothers and 7,388 twins, from Danish national registries. They found a total of 10,599 men who developed dementia later in life.

Their adjusted analysis of this group showed that there was about a 10% reduction in the risk of developing dementia for about every 6cm of height in individuals above the average height. When the team took into account the potential role of intelligence or education, the unadjusted relationship between height and dementia risk was only slightly reduced.

They found that the relationship between height and dementia also existed when they looked at brothers with different heights, suggesting that genetics and family characteristics alone do not explain why shorter men had a greater dementia risk. This was also true when they studied data concerning twins, although the results for this group were less certain.

"A key strength of our study is that it adjusted for the potential role of education and intelligence in young men's dementia risk, both of which may build up cognitive reserve and make this group less vulnerable to developing dementia," explains senior author Merete Osler, Professor at the Center for Clinical Research and Prevention, Bispebjerg and Frederiksberg Hospital, and at the University of Copenhagen.

'Cognitive reserve' refers to the brain's ability to improvise and solve problems that come up in everyday life. Osler says that adjusting for education and intelligence reduces the likelihood that the relationship between height and dementia is really explained by cognitive reserve.

"Together, our results point to an association between taller body height in young men and a lower risk of dementia diagnosis later in life, which persists even when adjusted for educational level and intelligence test scores," Osler says. "Our analysis of the data concerning brothers confirms these findings, and suggests the association may have common roots in early-life environmental exposures that are not related to family factors shared by brothers."

She adds that an important limitation of the study is the uncertainty as to whether these findings are generalisable to women, as previous studies on potential gender differences in the relationship between height and dementia are mostly inconclusive.

New insight on how a butterfly species developed the ability to adjust its wing eyespot size in response to temperature has been published today in eLife.

The study reveals that the African satyrid butterfly Bicyclus anynana (B. anynana), a member of the sub-family of the nymphalidae (or 'brush-footed') butterflies, changes its eyespot size using a complex physiological and molecular response that evolved gradually over millions of years. The findings also highlight that while temperature modulates hormone levels in various species of satyrid butterfly, B. anynana is just one of a few that take advantage of this response to regulate eyespot size.

Many butterflies in the nymphalidae family have circular eyespot patterns on their wings that are typically used to deflect attacks from predators. However, in certain seasons, such as the dry season in Africa, the butterflies' best survival strategy is to avoid drawing attention to themselves, and they will shrink the size of their eyespots to make them look like a dead leaf.

How butterflies accomplish this feat has only been studied in one species of African satyrid, B. anynana. In this species, low temperatures that signal the arrival of the dry season lower the quantity of a hormone called 20E during the late larval stage. This alters the function of hormone-sensitive cells in the centre of the eyespots and subsequently shrinks their size.

"For our study, we investigated how this hormone-mediated system came to regulate the size of eyespots by examining the process in several other species of butterflies with and without eyespots," explains lead author Shivam Bhardwaj, who conducted this work as part of his doctoral research in the Department of Biological Sciences at the National University of Singapore (NUS), and who is now a postdoctoral fellow at Mississippi State University. "We wanted to find out which other species change their eyespot size in response to temperature and whether they achieve this through the same mechanism as B. anynana. This comparative work would allow us to explore for the first time how a temperature-regulated system evolves at the genetic and physiological level."

To do this, Bhardwaj and his team reared 13 different species of satyrid at two different temperatures. They found that all species had lower levels of the 20E hormone in response to low temperatures, but most of them were unable to change the size of their eyespots accordingly. This included species that are known to have different eyespot sizes during wet and dry seasons. "We also saw that a small group of species expressed the hormone receptor in their eyespot centres just like B. anynana, but this also was also not sufficient to shrink its size," says Bhardwaj.

The team then manipulated the 20E hormone in four of the 13 species, and found that B. anynana is the only one to have evolved a temperature and hormone-mediated system of eyespot size regulation. They suggest that this species gradually evolved the ability to change its eyespot size according to temperature as a result of seasonal variations in its natural African habitat.

Further studies are now needed to understand the different environmental cues that other butterflies use to alter the size of their eyespots during dry and wet seasons.

"For now, our work uncovers a complex, gradual adaptation to seasonal environments in B. anynana that required specific mutations to evolve," says senior author Antónia Monteiro, Associate Professor at NUS and at Yale-NUS College, Singapore. "If other forms of adaptation are as difficult to evolve as the one identified in B. anynana, then our findings support a previous warning that many species may be vulnerable to extinction in the face of unpredictable and fluctuating temperatures caused by climate change."

An innovative manufacturing technique developed by KAUST researchers has led to the development of hybrid organic transistors for use in next-generation electronic displays and large-area electronics.

Thin-film transistors (TFTs) made from metal oxides have useful properties, including optical transparency and high charge-carrying capacity, and they are increasingly being used in organic light-emitting diode displays.

Currently, most TFTs are made using physical vapor deposition methods, but solution-based printing could hold promise for a simpler and more cost-effective approach. However, producing metal oxide TFTs with high carrier mobility and operating stability has proved challenging.

Led by Thomas Anthopoulos and colleagues from the KAUST Solar Center, an international team of researchers from the United Kingdom, China and Greece has made a hybrid TFT from solution-processed layers of polystyrene sandwiched between ultrathin sheets of indium oxide and zinc oxide nanoparticles.

"Much to our surprise, we discovered that the electron mobility of this hybrid TFT was very high," explains Anthopoulos. "But more importantly, we found that the ability of the device to sustain electrical bias for a long period of continuous operation, without changing its operating characteristics, has improved dramatically."

Previous work by Anthopoulos and colleagues had shown that TFTs made from two or more metal oxides can generate sheets of mobile electrons at the interface of the metal oxide layers. These electrons are free to move across the device, increasing its charge carrying capacity. However, structural defects present in the polycrystalline layers that form the interfaces produce election traps, altering the electrical properties of the device.

The researchers found that first inserting a polystyrene layer between the metal oxide layers and then applying an ultraviolet-ozone treatment to the layer caused the polystyrene to decompose into smaller molecular species that reacted with the oxide layers, strengthening the bonds between nanoparticles and removing some of the electron traps.

"The key to the success of our design is the incorporation of an ozone-treated polystyrene interlayer, which passivates the electron traps present on the surface/interface of the metal oxides and increases not only the electron mobility of the device but also its bias-stress stability," says Anthopoulos.

The work presents a simple, cost-effective and scalable method for fabricating TFTs for application in next-generation displays and a range of other large-area electronics.

"Next, we want to see if we can exploit the same electron trap passivation technique for different metal oxide semiconductors or other combinations of materials. I'm confident that we will identify even better-performing materials," says Anthopoulos.

Philadelphia, February 11, 2020 - Adolescents with a history of attention-deficit/hyperactivity disorder (ADHD) are at an increased risk for a multitude of adverse outcomes, including sexually-transmitted infections (STIs), mental health conditions, and car accidents. Researchers from Children's Hospital of Philadelphia (CHOP) wanted to better understand how primary care doctors addressed these risks with patients as they transitioned from childhood to young adulthood. They found that although doctors generally discuss depression, substance abuse, and suicide risk with patients who have a history of ADHD, they rarely discuss safe driving with them and most of the time they do not monitor patients for risky sexual behavior.

The findings, published in the Journal of Developmental and Behavioral Pediatrics, represent the first study to examine the clinical practices of primary care clinicians as children with ADHD advance through adolescence.

Although between 30% and 60% of children diagnosed with ADHD no longer meet full criteria for the disorder by late adolescence, those diagnosed before age 10 are at an increased risk for a variety of behavioral and medical concerns throughout adolescence. Yet of the 262 patients with a history of ADHD studied, the CHOP team found driving readiness was discussed in only two instances, and sexual health risks were discussed with only 47% of youth.

"These findings identify opportunities to improve the care of adolescents with a history of ADHD," said Thomas Power, PhD, ABPP, senior author and Director of the Center for Management of ADHD at CHOP. "Although doctors do a good job screening for many behavioral health risks, like suicide risk and depression, we need to be more aware of the dangers associated with driving and sexual health. For example, our previous research shows teens with ADHD are more likely to be involved in a car accident particularly in the first month after receiving their driver's license, so this is definitely an issue that should be discussed with our patients."

Medication abuse, specifically the unlawful sharing of medication among youth, is another major area of concern for adolescent patients on medication for ADHD, yet the study found doctors rarely discussed this risk with these patients.

"We have found that clinicians are more skilled in addressing ADHD in childhood than in adolescence," said Power. "Additional resources and training are needed so we can ensure primary care clinicians are providing the best care for patients with ADHD as they develop through their teenage years."

University of Bayreuth researchers, together with scientists from Italy and China, have for the first time systematically investigated under which conditions, and to what extent, sulphur-containing arsenic compounds are formed in rice-growing soils. To date, these thioarsenates have not been taken into account in assessments of the health effects of rice consumption. In the journal Nature Geoscience the scientists present their results and identify the urgent need for research with a view to protecting consumers from health risks.

A new measuring method for thioarsenates

The research team, headed by the Bayreuth environmental geochemist Prof. Dr. Britta Planer-Friedrich, has developed a measuring method by means of which thioarsenates in rice soils can be reliably detected. Up to now, the methods routinely used to monitor arsenic in rice fields have not been sufficient for this purpose. This is because they are not able to identify sulphur-containing arsenic compounds as such, or to distinguish them from oxygen-containing arsenic compounds. This shortcoming is highly problematic in terms of possible health risks. At least one organic sulphur-containing arsenic compound discovered in rice fields is already known to be carcinogenic. This makes it all the more important to specifically detect organic sulphur-containing arsenic compounds, and to examine them for their toxicity. Presumably, these compounds have been confused with non-toxic organic oxygenated arsenic compounds up to now due to inadequate measurement procedures.

Limit monitoring for all toxic arsenic compounds

"The uptake of the various thioarsenates in rice plants and the potential risks to human health arising from them urgently require further research. Rice is the world's most important foodstuff and secures the basis of life for more than one half of the world's population," explains Planer-Friedrich, and calls for legally defined limits to be set for all toxic arsenic compounds in future. "Analytical procedures for limit monitoring, which correctly detect all of these compounds, must become routine", says the Bayreuth scientist. At the moment, there is only a legal limit for inorganic oxygenated arsenic compounds, while organic oxygenated arsenic compounds are still categorized as non-toxic.

New approaches for forecasting methods

With their new measuring method, the researchers have observed the formation of sulphur-containing arsenic compounds over long periods of time in rice fields in Italy and China. It turns out the amounts of thioarsenates occurring are linked significantly to the pH-values of the soils and other easily measurable parameters. "These findings contain valuable starting points for the development of forecasting methods. If in future we could predict, without great technical effort, on which rice fields particularly large or only small amounts of sulphur-containing arsenic compounds are to be expected, it would be an important contribution to the assessment of health risks", says the Bayreuth PhD student and first author of the study, Jiajia Wang MSc.

Urgent need for research on opportunities and risks

The authors of the new study consider further research to be indispensable in order to be able to scientifically assess the health risks posed by thioarsenates. For example, the exact transport routes with which these arsenic compounds are transferred from the rice fields to the rice grains, and to what extent, must be clarified. Studies in Bayreuth laboratories have already confirmed that sulphur-containing arsenic compounds can enter the rice plant and even reach the rice grain. However, based on our current state of knowledge, it cannot be ruled out that the total arsenic contamination of rice harvests could even decrease if sulphur-containing instead of oxygen-containing arsenic compounds are formed in the soil. This would be the case if sulphur-containing arsenic compounds were largely retained in the soil, or if rice plants were less able to take up these compounds.

At the University of Bayreuth, these relationships are being investigated in the research groups of Prof. Dr. Britta Planer-Friedrich and of plant physiologist Prof. Dr. Stephan Clemens. The German Research Foundation (DFG) and the Federal Ministry of Education and Research (BMBF) are supporting these interdisciplinary research projects. "Our further studies will show whether thioarsenates as a whole represent a risk or an opportunity for the production of rice containing the lowest possible amounts of arsenic, which is hazardous to health. Only then can further directives for water or soil management in rice fields and the targeted breeding of new rice varieties be developed," says Planer-Friedrich.

NASA's Terra satellite passed over the South Pacific Ocean and found a stronger Tropical Cyclone Uesi after obtaining infrared imagery of the storm. Uesi continues moving away from Vanuatu and today is affecting New Caledonia.

Infrared data provides temperature information, and identifies the strongest thunderstorms that reach high into the atmosphere and have the coldest cloud top temperatures. On Feb. 11 at 6:15 a.m. EST (1115 UTC), the Moderate Resolution Imaging Spectroradiometer or MODIS instrument aboard NASA's Terra satellite gathered that temperature information about Uesi's cloud tops. MODIS found powerful thunderstorms south and east of the center of circulation where temperatures were as cold as or colder than minus 80 degrees Fahrenheit (minus 62.2 Celsius). Cloud top temperatures that cold indicate strong storms with the potential to generate heavy rainfall.

On Feb. 11, the Vanuatu Meteorology and Geo-Hazards Department (VMGD), in Port Vila issued an update on Uesi.  At 7:48 a.m. EST (11:48 p.m. Vanuatu local time), Tropical Cyclone Uesi was located at latitude 19.6 degrees south and longitude 162.6 east, about 435 miles (700 km) west of Tanna. Winds close to the center of the system have increased from near 55 mph (90 kph/50 knots) to 78 mph (125 kph/67 knots), making it equivalent to a Category 1 hurricane. Uesi was moving in a south-southeasterly direction. VMGD said that the potential for the system to recurve and move towards Vanuatu is low.

VMGD's final advisory on Uesi said, "Isolated heavy rainfalls may still be expected about [the] Vanuatu group today and tonight. Seas will remain very rough with heavy to phenomenal swells over coastal and open waters to the west of the Vanuatu group. Severe weather warning for heavy rainfalls for northern, central and southern provinces, while Marine strong wind warning for all coastal waters are current."

Meteo France, the forecast entity that provides forecasts for New Caledonia, which is located to the south-southwest of Vanuatu, is now feeling more of the effects from Uesi. On Feb. 11, Meteo France noted, "Uesi continues to move south passing west of Bélep and Grande-Terre a hundred kilometers (62 miles)." Rainbands continue to affect the whole territory and generate large accumulations of rain. As Uesi continues moving toward the south on Feb. 12, it is pulling away from New Caledonia. However, forecasters note that bands of thunderstorms can still bring heavy rainfall and gusty winds on Feb. 11. Highest rainfall is likely especially on the eastern side of the island.

For updates from VMGD's website: whttp://www.vmgd.gov.vu and VMGD's Facebook page: http://www.facebook.com/vmgd.gov.vu.

For updates on New Caledonia's forecast, visit Meteo France:  http://www.meteo.nc/

Tropical cyclones/hurricanes are the most powerful weather events on Earth. NASA's expertise in space and scientific exploration contributes to essential services provided to the American people by other federal agencies, such as hurricane weather forecasting.

Scientists have made a major breakthrough in understanding how the parasite that causes malaria is able to multiply at such an alarming rate, which could be a vital clue in discovering how it has evolved, and how it can be stopped.

For the first time, scientists have shown how certain molecules play an essential role in the rapid reproduction of parasite cells, which cause this deadly disease.

This could be the next step towards being able to prevent the malaria parasite from reproducing.

The research, which is co-led by Rita Tewari, Professor of Parasite Cell Biology in the School of Life Sciences at the University of Nottingham and Professor Karine Le Roch at the University of California Riverside, USA, could pave the way in helping to eradicate the disease.

The study, which is published in Cell Reports, was a collaborative effort with scientists from the Universities of Dundee, and Warwick in the UK, the University of Bern, Switzerland, ICGEB, India and the Francis Crick Institute.

Malaria is one of the world's biggest killer infections and is responsible for almost half a million deaths a year, mainly in tropical developing countries. The disease is caused by a one-celled parasite called Plasmodium. It is passed on from person to person as female Anopheles mosquitoes pick up the parasite from infected people when they bite to get the blood needed to nurture their eggs. Inside the mosquito the parasites reproduce, multiply and develop.

As part of their latest research, the team wanted to better understand how the parasite's cell divides and multiplies especially within a mosquito.

Proteins are large, complex molecules that play many critical roles in the body. They do most of the work in cells and are required for the structure, function, and regulation of the body's tissues and organs. Each organism has DNA organised into a certain number of chromosomes and needs condensins in order to 'split' this DNA when they multiply. Condensins are large protein complexes that play a central role in chromosome assembly and segregation during mitosis and meiosis.

In the malaria parasite (Plasmodium), the role of condensins in multiplication and proliferation was unclear. The team looked at two of the crucial condensin subunits, called SMC2 and SMC4, which are required to maintain the structure of chromosomes in a cell of other organisms.

Professor Tewari said: "We have tried to understand how these molecules work in the unusual pattern of multiplication by the parasite. We found that these molecules are there at all the stages of multiplication and they are present only at a certain part of the chromosome, which is called the centromere. We wanted to understand how does the parasite multiply? How do these molecules organise themselves and the DNA in those cells? It is fascinating how a single cell can carry out so many different modes of multiplication, and we need to understand how it does this."

After analysing the parasite, the team found a very unusual type of cell division, showing that the malaria parasite has evolved ways to ensure its survival by way of its cell division.

Professor Tewari says: "This particular parasite is very adaptable. Even if you kill it in the human blood stream, it can move into the mosquito stage. Over time, it has adapted to survive and has a lot of genetic plasticity, which is why it is difficult to control the disease.

"We need to understand what gives the parasite this plasticity and what it needs at every stage to survive, so it is crucial to understand how the parasite cell divides. The aim of our research is not to develop a drug immediately, but to answer the fundamental question of how the parasite divides and survives and the machinery it uses. The parasite has diverse modes of multiplying, so even if a drug or an effective vaccine is created, they may be able to adapt and we need to understand how. This is a next step towards that goal."

Professor Le Roch says: "By understanding the fundamental aspect of parasite biology, we are decrypting how the parasite divides, and how the different mechanisms regulating cell division can affect the ability of the parasite to thrive and replicate exponentially inside its hosts. If we identify the molecular components that are essential for the replication of this parasite, we will be able to develop novel and long-lasting therapeutic strategies against this devastating disease."

Researchers from Australia, Singapore, Taiwan and the UK placed cardboard cut-out models of the golden orb-weaver, Nephila pilipes, onto real webs in the field. Testing different combinations of colours and patterns they discovered that both the yellow colour and the black and yellow mosaic pattern are essential for luring prey during the day.

The webs of Nephila pilipes also capture prey during the night, and the experiments demonstrated that the yellow colour alone was very effective at luring nocturnal insects.

Orb-weaving spiders are found in different light conditions, and comparisons between many different species revealed a link between light environments and orb-weaver body colour patterns. Species that build their webs in well-lit environments are more likely to evolve the yellow mosaic colour pattern, found to be so effective at luring prey in these experiments.

However, this colour pattern rarely evolves in species that have little opportunity to lure prey, perhaps because they are concealed in a retreat or build their webs in dark caves.

Dr Po Peng, lead author of the study, said, "Our discoveries indicate that the effectiveness of colour-luring to attract prey might be a major driver for the yellow mosaic pattern being present in distantly related orb-weaver spiders."

The significance of the yellow colour may be due to yellow pollen and flower heads being common in flowers that signal to diurnal (active during the day) pollinators. Previous research has also found that some nocturnal (active at night) lepidoptera (moths and butterflies) can discriminate colours under dim light conditions and innately prefer yellow.

Orb weaving spiders comprise around 12,500 species, making up 28% of the 45,000 described spider species. The groups defining trait is that they construct webs which they sit in the middle of to forage for prey.

Nephila pilipes were used in these experiments as they are active both diurnally and nocturnally, making them excellent species to study visual prey lures. Flies and bees make up the majority of their diurnal prey; moths and butterflies make up the majority of their nocturnal prey.

The researchers conducted the field experiments at Huayan Mountain in Taiwan between 2008 - 2009. They created five types of carboard models that looked like Nephila pilipes with their legs outstretched. One accurately mimicked the spiders' natural colouration (shown in video). The second had blue spots rather than yellow to test the importance of colour. The third amalgamated the combined area of the yellow into one area to test the importance of the pattern. The fourth and fifth model types were entirely yellow and entirely black.

"To find paper with colour properties most similar to the body parts of N. pilipes, Szu-Wei Chen (co-author) and I did several tours over dozens of stationery stores collecting samples and measuring their reflectance." Said Po Peng.

In the field experiments the researchers removed a live spider from its web and randomly selected one of the models to be placed in the centre. They recorded the responses of insects to the cardboard spiders, collecting a combined 1,178 hours of video footage over day and night.

In this study the researchers only looked at the effects of the spiders' colour and pattern on luring prey and not how they're perceived by predators. "Previous studies suggest that the area of bright body parts is constrained by diurnally active, visually hunting predators" said Po Peng, "But our results indicated that the yellow mosaic pattern on nocturnal spiders does not represent a trade-off between prey attraction and predator avoidance." The effect of both colour and pattern on risk from predators or parasitoids is something the researchers feel warrants further investigation.

A single strain of mumps virus has dominated the US since 2006, and is responsible for many of the large numbers of cases seen across the country in the widespread 2016-17 outbreaks. In a paper publishing February 11 in the open-access journal PLOS Biology, Pardis Sabeti from the Broad Institute of MIT and Harvard and colleagues analyze over 200 whole mumps virus genomes from patient swab samples, providing insights not obtained in standard public health surveillance efforts.

An unusually high number of mumps cases were reported in the US in 2016 and 2017, despite high rates of vaccination. The recent resurgence is partly explained by reduced vaccine-induced immunity but it was unclear how much genetic changes in the circulating viruses might be contributing to this.

The researchers sequenced whole mumps virus genomes from 203 patients, mostly from Massachusetts during 2016/17, but including 43 from other states collected between 2014 and 2017. Combining the whole genome sequences with epidemiological data, their analysis demonstrates the extent to which the disease is circulating in the United States, connects outbreaks previously thought to be unrelated, and traces transmission between communities.

The research indicates the value of high-quality genomic data in public health surveillance of mumps and suggests future efforts should incorporate whole genome sequencing. Pardis Sabeti says: "Understanding sequence data for pathogens like mumps virus can help understanding of the spread of infectious diseases more quickly and allow researchers to detect changes in the genome that could affect disease severity or the effectiveness of vaccines and diagnosis."

Cryogenic electron microscopy, or cryo-EM, has reached the point where researchers could in principle image individual atoms in a 3D reconstruction of a molecule - but just because they could see those details doesn't always mean they do. Now, researchers at the Department of Energy's SLAC National Accelerator Laboratory and Stanford University have proposed a new way to quantify how accurate such reconstructions are and, in the process, how confident they can be in their molecular interpretations.

Cryo-EM works by freezing biological molecules which can contain thousands of atoms so they can be imaged under an electron microscope. By aligning and combining many two-dimensional images, researchers can compute three-dimensional maps of an entire molecule, and this technique has been used to study everything from battery failure to the way viruses invade cells. However, an issue that has been hard to solve is how to accurately assess the true level of detail or resolution at every point in such maps and in turn determine what atomic features are truly visible or not.

Wah Chiu, a professor at SLAC and Stanford, Grigore Pintilie, a computational scientist in Chiu's group, and colleagues devised the new measures, known as Q-scores, to address that issue. To compute Q-scores, scientists start by building and adjusting an atomic model until it best matches the corresponding cryo-EM derived 3D map. Then, they compare the map to an idealized version in which each atom is well-resolved, revealing to what degree the map truly resolves the atoms in the atomic model.

The researchers validated their approach on large molecules, including a protein called apoferritin that they studied in the Stanford-SLAC Cryo-EM Facilities. Kaiming Zhang, another research scientist in Chiu's group, produced 3D maps close to the highest resolution reached to date - up to 1.75 angstrom, less than a fifth of a nanometer. Using such maps, they showed how Q-scores varied in predictable ways based on overall resolution and on which parts of a molecular they were studying. Pintilie and Chiu say they hope Q-scores will help biologists and others using cryo-EM better understand and interpret the 3D maps and resulting atomic models.

Some smartphone apps that assess the risk of suspicious moles cannot be relied upon to detect all cases of skin cancer, finds a review of the evidence published by The BMJ today.

The researchers warn that the current regulatory process for these apps "does not provide adequate protection to the public."

The World Health Organization estimates between 2 and 3 million non-melanoma skin cancers and 132,000 melanoma skin cancers occur globally each year, but survival is high if melanoma is spotted early, which makes prompt detection and treatment crucial.

Artificially intelligent (AI) smartphone apps offer the potential for earlier detection and treatment of suspicious moles. But they could be harmful, particularly if false reassurance leads to delays in people seeking medical advice.

In Europe, two apps (SkinVision
and TeleSkin skinScan) are currently available and are regulated as class 1 medical devices (deemed to have a low to moderate risk to the user). No apps currently have US Food and Drug Administration (FDA) approval.

A previous expert review of such apps suggested there is a high chance of skin cancers being missed.

So a research team led by Professor Jon Deeks at the University of Birmingham and Professor Hywel Williams at the University of Nottingham, set out to examine the validity and findings of studies looking at the accuracy of algorithm based smartphone 'skin' apps.

Nine relevant studies that evaluated six different apps were identified. Studies were small and overall of poor quality.

Problems in the studies included the suspicious moles were chosen by clinicians not the app users, the photographs were taken by trained researchers on study phones, not by users on their own phones, and photographs that could not be evaluated by the apps were excluded. Also study participants were not followed up to identify cancers which were missed by the apps.

No published studies were found that evaluated the TeleSkin skinScan app.

SkinScan was evaluated in a single study of 15 moles with five melanomas. The app did not identify any of the melanomas.

SkinVision was evaluated in three studies. One study of 108 moles (35 cancerous or precancerous moles) achieved a sensitivity of 88% and a specificity of 79%. This means that 12% of patients with cancerous or precancerous moles would be missed, while 21% of those non-problematic moles would be wrongly identified as potentially being cancerous.

To put this into context, the authors explain that in a population of 1000 users in which 3% have a melanoma, SkinVision could still miss four of 30 melanomas and 200 people would wrongly be told their mole was of high concern. But they point out that the limitations of the studies suggest that more errors are likely to be made.

They point out that both SkinVision and SkinScan are currently being marketed with claims that they can "detect skin cancer at an early stage" or "track moles over time with the aim of catching melanoma at an earlier stage of the disease."

"Our review found poor and variable performance of algorithm based smartphone apps, which indicates that these apps have not yet shown sufficient promise to recommend their use," write the authors.

They warn that the current regulatory processes "are inadequate for protecting the public against the risks created by using smartphone diagnostic or risk stratification apps."

And they say healthcare professionals "need to be aware of the limitations of algorithm based apps to reliably identify melanomas, and should inform potential smartphone app users about these limitations."

It is positive to see healthcare systems embracing data analytics and machine learning. However, little evidence indicates that current AI apps can beat the clinician when assessing skin lesion risk - at least not in a verifiable or reproducible form, argue researchers at the University of Oxford, in a linked editorial.

They say the implications for patients, regulators, and clinicians are substantial, and call for several measures to improve transparency (driving up overall quality), and enable better reproducibility and audit by the wider research community.

Without such measures, patients, clinicians, and other stakeholders cannot be assured of apps' safety and efficacy, they conclude.

Maunakea, Hawaii - A team of astronomers led by Brendan Bowler of The University of Texas at Austin has probed the formation process of giant exoplanets and brown dwarfs, a class of objects that are more massive than giant planets, but not massive enough to ignite nuclear fusion in their cores to shine like true stars.

Using direct imaging with ground-based telescopes in Hawaii - W. M. Keck Observatory and Subaru Telescope on Maunakea - the team studied the orbits of these faint companions orbiting stars in 27 systems. These data, combined with modeling of the orbits, allowed them to determine that the brown dwarfs in these systems formed like stars, but the gas giants formed like planets.

The research is published in the current issue of The Astronomical Journal.

In the last two decades, technological leaps have allowed telescopes to separate the light from a parent star and a much-dimmer orbiting object. In 1995, this new capability produced the first direct images of a brown dwarf orbiting a star. The first direct image of planets orbiting another star followed in 2008.

"Over the past 20 years, we've been leaping down and down in mass," Bowler said of the direct imaging capability, noting that the current limit is about 1 Jupiter mass. As the technology has improved, "One of the big questions that has emerged is 'What's the nature of the companions we're finding?'"

Brown dwarfs, as defined by astronomers, have masses between 13 and 75 Jupiter masses. They have characteristics in common with both planets and with stars, and Bowler and his team wanted to settle the question: Are gas giant planets on the outer fringes of planetary systems the tip of the planetary iceberg, or the low-mass end of brown dwarfs? Past research has shown that brown dwarfs orbiting stars likely formed like low-mass stars, but it's been less clear what is the lowest mass companion this formation mechanism can produce.

"One way to get at this is to study the dynamics of the system -- to look at the orbits," Bowler said. Their orbits today hold the key to unlocking their evolution.

Using Keck Observatory's adaptive optics (AO) system with the Near-Infrared Camera, second generation (NIRC2) instrument on the Keck II telescope, as well as the Subaru Telescope, Bowler's team took images of giant planets and brown dwarfs as they orbit their parent stars.

It's a long process. The gas giants and brown dwarfs they studied are so distant from their parent stars that one orbit may take hundreds of years. To determine even a small percentage of the orbit, "You take an image, you wait a year," for the faint companion to travel a bit, Bowler said. Then "you take another image, you wait another year."

This research relied on AO technology, which allows astronomers to correct for distortions caused by the Earth's atmosphere. As AO instruments have continually improved over the past three decades, more brown dwarfs and giant planets have been directly imaged. But since most of these discoveries have been made over the past decade or two, the team only has images corresponding to a few percent of each object's total orbit. They combined their new observations of 27 systems with all of the previous observations published by other astronomers or available in telescope archives.

At this point, computer modeling comes in. Coauthors on this paper have helped create an orbit-fitting code called "Orbitize!" which uses Kepler's laws of planetary motion to identify which types of orbits are consistent with the measured positions, and which are not.

The code generates a set of possible orbits for each companion. The slight motion of each giant planet or brown dwarf forms a "cloud" of possible orbits. The smaller the cloud, the more astronomers are closing in on the companion's true orbit. And more data points -- that is, more direct images of each object as it orbits -- will refine the shape of the orbit.

"Rather than wait decades or centuries for a planet to complete one orbit, we can make up for the shorter time baseline of our data with very accurate position measurements," said team member Eric Nielsen of Stanford University. "A part of Orbitize! that we developed specifically to fit partial orbits, OFTI [Orbits For The Impatient], allowed us to find orbits even for the longest period companions."

Finding the shape of the orbit is key: Objects that have more circular orbits probably formed like planets. That is, when a cloud of gas and dust collapsed to form a star, the distant companion (and any other planets) formed out of a flattened disk of gas and dust rotating around that star.

On the other hand, the ones that have more elongated orbits probably formed like stars. In this scenario, a clump of gas and dust was collapsing to form a star, but it fractured into two clumps. Each clump then collapsed, one forming a star, and the other a brown dwarf orbiting around that star. This is essentially a binary star system, albeit containing one real star and one "failed star."

"Even though these companions are millions of years old, the memory of how they formed is still encoded in their present-day eccentricity," Nielsen added. Eccentricity is a measure of how circular or elongated an object's orbit is.

The results of the team's study of 27 distant companions was unambiguous.

"The punchline is, we found that when you divide these objects at this canonical boundary of more than about 15 Jupiter masses, the things that we've been calling planets do indeed have more circular orbits, as a population, compared to the rest," Bowler said. "And the rest look like binary stars."

The future of this work involves both continuing to monitor these 27 objects, as well as identifying new ones to widen the study. "The sample size is still modest, at the moment," Bowler said. His team is using the Gaia satellite to look for additional candidates to follow up using direct imaging with even greater sensitivity at the forthcoming Giant Magellan Telescope (GMT) and other facilities. UT-Austin is a founding member of the GMT collaboration.

Bowler's team's results reinforce similar conclusions recently reached by the GPIES direct imaging survey with the Gemini Planet Imager, which found evidence for a different formation channel for brown dwarfs and giant planets based on their statistical properties.

This work was supported by a NASA Keck PI Data Award, administered by the NASA Exoplanet Science Institute. The Keck Observatory is managed by Caltech and the University of California.

Wearable tech and electronic cloth may be the way of the future, but to get there the wiring needs to be strong, flexible and efficient.

Boron nitride nanotubes (BNNT), studied by physicists at Michigan Technological University, encase tellurium atomic chains like a straw, which could be controllable by light and pressure. In collaboration with researchers from Purdue University, Washington University and University of Texas at Dallas, the team published their findings in Nature Electronics this week.

As demand for smaller and faster devices grows, scientists and engineers turn to materials with properties that can deliver when existing ones lose their punch or can't shrink enough.

For wearable tech, electronic cloth or extremely thin devices that can be laid over the surface of cups, tables, space suits and other materials, researchers have begun to tune the atomic structures of nanomaterials. The materials they test need to bend as a person moves, but not go all noodly or snap, as well as hold up under different temperatures and still give enough juice to run the software functions users expect out of their desktops and phones. We're not quite there with existing or preliminary technology -- yet.

As implied by the "tube" of their nanostructure, BNNTs are hollow in the middle. They're highly insulating and as strong and bendy as an Olympic gymnast. That made them a good candidate to pair with another material with great electrical promise: tellurium. Strung into atom-thick chains, which are very thin nanowires, and threaded through the hollow center of BNNTs, tellurium atomic chains become a tiny wire with immense current-carrying capacity.

"Without this insulating jacket, we wouldn't be able to isolate the signals from the atomic chains. Now we have the chance to review their quantum behavior," Yap said. "The is the first time anyone has created a so-called encapsulated atomic chain where you can actually measure them. Our next challenge is to make the boron nitride nanotubes even smaller."

A bare nanowire is kind of a loose cannon. Controlling its electric behavior -- or even just understanding it -- is difficult at best when it's in rampant contact with flyaway electrons. Nanowires of tellurium, which is a metalloid similar to selenium and sulfur, is expected to reveal different physical and electronic properties than bulk tellurium. Researchers just needed a way to isolate it, which BNNTs now provide.

"This tellurium material is really unique. It builds a functional transistor with the potential to be the smallest in the world," said Peide Ye, the lead researcher from Purdue University, explaining that the team was surprised to find through transmission electron microscopy at the University of Texas at Dallas that the atoms in these one-dimensional chains wiggle. "Silicon atoms look straight, but these tellurium atoms are like a snake. This is a very original kind of structure."

The tellurium-BNNT nanowires created field-effect transistors only 2 nanometers wide; current silicon transistors on the market are between 10 to 20 nanometers wide. The new nanowires current-carrying capacity reached 1.5x10^8 cm2, which also beats out most semiconducting nanowires. Once encapsulated, the team assessed the number of tellurium atomic chains held within the nanotube and looked at single and triple bundles arranged in a hexagonal pattern.

Additionally, the tellurium-filled nanowires are sensitive to light and pressure, another promising aspect for future electronics. The team also encased the tellurium nanowires in carbon nanotubes, but their properties are not measurable due to the conducting or semiconducting nature of carbon.

While tellurium nanowires have been captured within BNNTs, like a firefly in a jar, much of the mystery remains. Before people begin sporting tellurium T-shirts and BNNT-laced boots, the nature of these atomic chains needs characterizing before its full potential for wearable tech and electronic cloth can be realized.