Culture

Digital traces from credit card and mobile phone usage can be used to map urban lifestyles and understand human mobility, according to a report led by UCL, MIT and UC Berkeley.

Credit Card Records (CCRs) are currently used to measure similarities in purchasing activity, but for the first time researchers have used the data along with Call Detailed Records (CDRs) to understand the daily rhythms of human mobility and communication.

Combining both reveals patterns in citizens' socio-economic behaviours.

For the study, published today in Nature Communications, researchers used anonymous and aggregated credit card data from a major city, with the results allowing them to group the urban population into six clusters.

Older women dominated the 'Homemaker' cluster and tended to have the least expenditure and mobility, with their core transaction being grocery shops. The 'Commuters' cluster was mainly men who lived the farthest from the city centre.

Young people can be split into two groups, with the younger having taxis as their core transaction. The slightly older group also has computer networks and information services, with a higher than average expenditure and operating mainly within the city centre.

The research, conducted in collaboration with Grandata and UN Global Pulse, is part of a wider project funded by the United Nations Foundation and the Gates Foundation to investigate the economic, social and health status of women and girls in developing countries.

Lead researcher Dr Riccardo Di Clemente (UCL Centre for Advance Spatial Analysis), said: "Our approach brings together human mobility behavioural dynamics with socio-economic and demographic information.

"This may enable policymakers to make more informed decisions about resource allocations to address socio-economic inequality, economic growth and improve social cohesion."

Principal investigator Professor Marta C. Gonzalez (UC Berkeley College of Environmental Design), said: "Mobile phone data is already used for transport planning. Through this research we found that credit card data can allow us to understand how groups of citizens move and communicate, as well as revealing their spending patterns.

"The method gives us a lot of information from data passively collected worldwide, uncovering purchase sequences of uses by type and their role in their space and social network."

The team found that analysing CCRs together with CDRs reveals how women cope with stressors such as recessions and macroeconomic policy shifts, and could be used when planning systems to enable more women to use mobile money rather than carry cash.

The method and results can be used when designing and managing effective social protection systems in developing countries and could be particularly valuable for urban development, such as planning infrastructure and mapping neighbourhoods.

BOSTON, Aug. 20, 2018 -- Saliva is crucial for tasting and digesting food, but scientists have now found that it may have another, more subtle role. Salivary proteins could be part of a feedback loop that influences how food tastes to people -- and by extension, what foods they're willing to eat. The researchers hope that, one day, their findings could help consumers stick to a healthier diet.

They will present their results today at the 256th National Meeting & Exposition of the American Chemical Society (ACS). ACS, the world's largest scientific society, is holding the meeting here through Thursday. It features more than 10,000 presentations on a wide range of science topics.

Many healthy foods -- like broccoli and dark chocolate -- taste bitter, Cordelia A. Running, Ph.D., says. She set out to see if eating bitter foods would help people overcome an aversion to bitter compounds. Thus, they could eat more of these healthy foods without cringing. "By changing your diet, you might be able to change your flavor experience of foods that at one point tasted nasty to you," she says.

While saliva consists almost entirely of water, it also contains thousands of proteins released by salivary glands. Some of these proteins are thought to bind to flavor compounds in food and also to taste receptor cells in the mouth. Certain proteins may be responsible for the astringent sensations, such as dryness and roughness, that develop when eating some chocolates, red wine and other foods. "If we can change the expression of these proteins, maybe we can make the 'bad' flavors like bitterness and astringency weaker," says Running, who is based at Purdue University and is the principal investigator of the study.

In prior work with rats, Running's fellow researcher Ann-Marie Torregrossa, Ph.D., and colleagues showed that a bitter diet altered expression of proteins in the rodents' saliva. Those changes in protein composition correlated with the rats' feeding behavior. After initially cutting back on bitter foods, the animals apparently experienced less bitterness and resumed normal eating levels. Inspired by the work of Torregrossa, who is now at the University at Buffalo, Running decided to see if the same thing would happen in people.

Running's team carried out sensory evaluation tests in which they asked participants to drink chocolate almond milk three times a day for a week and rate its bitterness and astringency. The researchers found that the protein composition of the participants' saliva changed during that week. Several proline-rich proteins, which can bind the bitter/astringent compounds in chocolate, increased after drinking the chocolate almond milk. The changes in these proteins corresponded to changes in sensory ratings: As these proteins shifted up, the sensory ratings for bitterness and astringency shifted down. "We think the body adapts to reduce the negative sensation of these bitter compounds," Running explains.

The findings to-date support the idea that "saliva modifies flavor, which in turn modifies dietary choices," she says. "Those choices then influence exposure to flavors, which over time may stimulate altered expression of saliva proteins, and the circle begins anew. Maybe this knowledge will help someone stick to a healthier diet long enough to adapt to like it."

Running plans to investigate the particular compounds in food that elicit changes in salivary proteins. In chocolate, for example, she wants to know what concentration of bitter polyphenols is necessary to affect expression of salivary proteins. She also wants to assess how long it takes to reduce the bitter taste of any given food and whether mimics for salivary proteins could someday be added to food to improve its flavor.

BOSTON, Aug. 19, 2018 -- The life-threatening bacteria called MRSA can cripple a hospital since it spreads quickly and is resistant to treatment. But scientists report that they are now making advances in a new technique that avoids antibiotics. Instead, they are using light to activate oxygen, which then wipes out antibiotic-resistant bacteria. The method also could be used to treat other microbial infections, and possibly even cancer.

The researchers are presenting their results today at the 256th National Meeting & Exposition of the American Chemical Society (ACS). ACS, the world's largest scientific society, is holding the meeting here through Thursday. It features more than 10,000 presentations on a wide range of science topics.

Clinical facilities currently have few alternatives when trying to rid their patients of MRSA (methicillin-resistant Staphylococcus aureus). The Veterans Health Care System, for example, hires infection prevention staff to track hand hygiene. Going even further, one recent study found that disinfecting every patient admitted to an acute-care setting cut the rate of bloodstream infections in half. However, this procedure isn't feasible at most hospitals.

"Instead of resorting to antibiotics, which no longer work against some bacteria like MRSA, we use photosensitizers, mostly dye molecules, that become excited when illuminated with light," Peng Zhang, Ph.D., says. "Then, the photosensitizers convert oxygen into reactive oxygen species that attack the bacteria."

Although other teams have experimented with using these types of photocatalysts to kill bacteria, they did not destroy enough microorganisms to effectively shake off infections. Photosensitizers in a molecular form tend to not be corralled enough to do significant damage. In addition, many of them are hydrophobic. This makes it difficult to disperse them in aqueous media where microorganisms typically exist. To overcome these challenges, Zhang's group collaborated with Neil Ayres, Ph.D., and his team. Both are at the University of Cincinnati. They set out to design a new, water-dispersible, hybrid photosensitizer -- one that includes noble metal nanoparticles decorated with amphiphilic polymers to entrap the molecular photosensitizers.

The team showed that the new nanoparticle photosensitizer was much more effective at killing a variety of bacteria than corresponding formulations that did not contain the metal particles. According to Zhang, these nanoparticles provide two benefits. The metal has a plasmonic enhancement effect that promotes the generation of more reactive oxygen species, while also concentrating the photosensitizers in one place for a more localized hit to the bacterial cells.

Zhang explains it this way: "If you want to attack a castle, and you just let all these people attack individually, it is not very effective. Instead, if you have the same number of people grouped together attacking the castle at one point, it is possible to cause more damage."

Zhang has a patent related to the design of hybrid photosensitizers, which can be formulated into a spray or gel. He says that once the spray is developed into a product, medical professionals could put it on any surface and then illuminate it with blue or red light to clean away the bacteria, including MRSA, that may be present. Zhang also says that the method shows promise in direct wound applications to eliminate infection and assist in healing. He has recently performed experiments on laboratory samples of human skin and found that the photosensitizer didn't kill skin cells.

In addition to eradicating MRSA, the nanoparticles are ideal for destroying skin cancer cells, Zhang says. The nanoparticles perform effectively with the illumination of red light, which has a long wavelength that penetrates deep below the skin -- something that's important for a skin cancer treatment. Finally, the nanoparticles have been shown to eliminate nail bed fungus.

TORONTO, August 17, 2018 - Adolescent girls and young women in Mombasa, Kenya are more likely to experience higher risks of HIV and gender-based violence when they are involved with sex work venues or have sexual experiences at a young age, suggests a study co-led by St. Michael's Hospital and the University of Manitoba in Canada.

Published in the Journal of Acquired Immune Deficiency Syndromes (JAIDS), the research suggests that the conditions of a first sexual encounter, such as a woman's age, the man's age, use of condoms, and whether or not the encounter is consensual can be indicators of future risk of HIV infection and gender-based violence.

The research team found that adolescent girls and young women in Mombasa, Kenya, who are forced or coerced in their first sexual experience, are four to five times more likely to face ongoing gender-based violence throughout their lifetime. This research also showed that one in four participants experience gender-based violence after their first sexual experience, with 37.5 per cent prevalence amongst those involved in sex work.

Dr. Sharmistha Mishra, a scientist at the Li Ka Shing Knowledge Institute of St. Michael's Hospital and one of the study's lead authors, and her team found that women who experienced their first sexual encounter before the age of 15 were two times more likely to be at risk of HIV acquisition. This was especially prevalent for those in the sex work industry and those who frequented sex work venues.

"We wanted to understand early risk and vulnerabilities for HIV because many prevention programs for key populations reach young sex workers several years after they have already experienced high-risk encounters," Dr. Mishra said. "There are vulnerabilities that appear in the first few years of becoming sexually active and entering sex work more formally."

The study's results were drawn from a cross-sectional biological and behavioural survey conducted among sexually active adolescent girls and young women in Mombasa, Kenya. Community organizations, including past and current female sex workers working with the International Centre for Reproductive Health Kenya, identified participants at local sex work hotspots who then participated in interviews and HIV testing. Participants were referred to HIV prevention and care programs in Mombasa.

"Global health partnerships are strongest when there is a generation of new knowledge that informs programs led on the ground," said Dr. Mishra, speaking of this work's partnership between St. Michael's Hospital, the University of Toronto, the University of Manitoba, and the National AIDS and STI Control Programme in Kenya.

This research is part of a multi-component study designed to count how many young women are involved in sex work in Mombasa, Kenya; measure early HIV risks through a representative survey; and conduct mathematical modelling to understand the impact of not accounting for the early risk many young women face.

"We've identified a need to provide HIV prevention and treatment plans for adolescent girls and young women at an earlier age," Dr. Marissa Becker, associate professor at the University of Manitoba and co-lead of the study. "We hope the findings of this research can assist HIV prevention programs to adapt their strategies to reach vulnerable young women and teenaged girls at a younger age and intervene on risks early on."

Dr. Becker, Dr. Mishra and their team are continuing to conduct programmatic and mathematical modeling studies in this area, with a hope to implement and evaluate new programs and interventions. They are also looking at how their findings in Kenya are applicable to other countries.

How much do you change between high school and retirement? The answer depends on whether you're comparing yourself to others or to your younger self.

The results of a new study, the first to test how personality might change over 50 years and relying on the same data source at both time points, finds that broad patterns of thoughts, feelings and behaviors - personality - do change, and this change appears to accumulate with time. But don't compare yourself to others; those who are the most emotionally stable when young are probably going to continue being the most stable as they age.

"The rankings (of personality traits) remain fairly consistent. People who are more conscientious than others their age at 16 are likely to be more conscientious than others at 66," said Rodica Damian, assistant professor of psychology at the University of Houston and lead author of a new study on the subject. "But, on average, everyone becomes more conscientious, more emotionally stable, and more agreeable.

Still, she said, researchers did find individual differences in change across time, with some people changing more than others and some changing in more maladaptive or harmful ways.

The work, "Sixteen Going on Sixty-Six: A Longitudinal Study of Personality Stability and Change across 50 Years," was published Aug. 16 in the Journal of Personality and Social Psychology.

Social scientists have long debated whether personality is stable - unchanged over time - or malleable. Recent studies have indicated it might be both, but longitudinal studies covering very long timespans and relying on the same data source at both time points are rare.

The new research supports the idea that personality is influenced by both genetics and environment.

Personality is described as patterns of thoughts, feelings and behaviors, consisting of five major traits: conscientiousness, agreeableness, openness to experiences, extraversion, and emotional stability. Damian said those five traits have been found across ages and cultures.

The combination of those traits - how dominant each trait is in a given individual relative to the other traits -makes up the personality profile.

With co-authors Marion Spengler of the University of Tuebingen in Germany, Brent W. Roberts of the University of Illinois at Urbana-Champaign, and Andreea Sutu, a graduate student working with Damian at UH, Damian used a dataset of U.S. high school students who answered a series of questions to assess personality in 1960 and again 50 years later.

Data from the Project Talent Personality Inventory allowed the researchers to answer several questions, including:

To what extent do people maintain their relative standing on personality traits compared with other people - for example, do people who are more impulsive than most of their peers at age 16 remain more impulsive than their peers at age 60?

To what extent do average levels of personality traits change? Are people, on average, more conscientious at 66 than at 16?

Does everyone change in the same way?

Are there gender differences in patterns of personality stability and change across time?

"Our findings suggest that personality has a stable component across the lifespan, both at the trait level and at the profile level, and that personality is also malleable and people mature as they age," the researchers wrote. They found gender differences in personality at any given time, Damian said, but, overall, men and women changed at the same rates across the lifespan.

What has been found? That the known masses and sizes of many exoplanets of two to four times the size of Earth can be explained by large amounts of water.

Why is it important? Water has been implied previously on individual exoplanets, but this work concludes that water-rich planets are common. This bodes well for planet formation of Earth-like planets with water and the search for life beyond our Solar System.

Scientists have shown that water is likely to be a major component of those exoplanets (planets orbiting other stars) which are between two to four times the size of Earth. It will have implications for the search of life in our Galaxy. The work is presented at the Goldschmidt conference in Boston.

The 1992 discovery of exoplanets orbiting other stars has sparked interest in understanding the composition of these planets to determine, among other goals, whether they are suitable for the development of life. Now a new evaluation of data from the exoplanet-hunting Kepler Space Telescope and the Gaia mission indicates that many of the known planets may contain as much as 50% water. This is much more than the Earth's 0.02% (by weight) water content.

"It was a huge surprise to realize that there must be so many water-worlds", said lead researcher Dr Li Zeng (Harvard University),

Scientists have found that many of the 4000 confirmed or candidate exoplanets discovered so far fall into two size categories: those with the planetary radius averaging around 1.5 that of the Earth, and those averaging around 2.5 times the radius of the Earth.

Now a group of International scientists, after analyzing the exoplanets with mass measurements and recent radius measurements from the Gaia satellite, have developed a model of their internal structure.

"We have looked at how mass relates to radius, and developed a model which might explain the relationship", said Li Zeng. The model indicates that those exoplanets which have a radius of around x1.5 Earth radius tend to be rocky planets (of typically x5 the mass of the Earth), while those with a radius of x2.5 Earth radius (with a mass around x10 that of the Earth) are probably water worlds".

"This is water, but not as commonly found here on Earth", said Li Zeng. "Their surface temperature is expected to be in the 200 to 500 degree Celsius range. Their surface may be shrouded in a water-vapor-dominated atmosphere, with a liquid water layer underneath. Moving deeper, one would expect to find this water transforms into high-pressure ices before we reaching the solid rocky core. The beauty of the model is that it explains just how composition relates to the known facts about these planets".

Li Zeng continued, "Our data indicate that about 35% of all known exoplanets which are bigger than Earth should be water-rich. These water worlds likely formed in similar ways to the giant planet cores (Jupiter, Saturn, Uranus, Neptune) which we find in our own solar system. The newly-launched TESS mission will find many more of them, with the help of ground-based spectroscopic follow-up. The next generation space telescope, the James Webb Space Telescope*, will hopefully characterize the atmosphere of some of them. This is an exciting time for those interested in these remote worlds".

Professor Sara Seager, Professor of Planetary Science at Massachusetts Institute of Technology, and deputy science director of the recently-launched TESS (Transiting Exoplanet Survey Satellite) mission, which will search for exoplanets, said:

"It's amazing to think that the enigmatic intermediate-size exoplanets could be water worlds with vast amounts of water. Hopefully atmosphere observations in the future--of thick steam atmospheres---can support or refute the new findings".

KINGSTON, R.I. - August 16, 2018 - Jason Kolbe has been thinking about hurricanes and lizards for many years.

The University of Rhode Island professor of biological sciences has measured the length of lizard legs and the size of their toe pads to assess how those factors influence the animal's ability to cling to vegetation during strong storms. He even used a powerful leaf blower to test his hypotheses in a laboratory.

"I think a lot about this," he said. "We know that longer limbs and more muscular limbs enable lizards to wrap their arms around branches and get a better grip on the vegetation."

But until the perfect storm of circumstances arose last year, he was never able to field test his ideas.

A postdoctoral colleague at Harvard University happened to measure the limb length and toe pads of lizards on the Turks and Caicos Islands just four days before Hurricane Irma swept through with 165-mile-per-hour winds last September. Two weeks later, Hurricane Maria followed suit.

The storms provided the scientists with the unusual opportunity to see how hurricanes affect the evolution of the lizards. So Kolbe's colleague returned to the islands to measure the surviving lizards just weeks after the hurricanes. Their findings were published last month in the journal Nature.

"Our previous studies suggested that lizards with longer limbs and larger toe pads can cling better, so we expected that the lizards that survived the storms would be those with longer limbs and larger toe pads," Kolbe said. "And our prediction was supported for the toe pads and the forelimbs. But the survivors had shorter hind limbs, which was a surprise."

When the researchers watched the videos they previously made of their experiment with the lizards and the leaf blower, they understood why the surviving lizards had shorter hind limbs.

"When the lizards start to get blown by the wind, their hind limbs lose contact with the vegetation first, so they're holding on only with their forelimbs," he explained. "When they're perched on vegetation, their hind limbs stick out and catch the wind. It turns out that lizards with shorter hind limbs have an advantage in a hurricane."

What does all this have to do with evolution?

"The event we documented seems to be about natural selection. Some lizards lived, some lizards died," Kolbe said. "To translate that to evolutionary change, those surviving lizards have to reproduce and those traits - longer forelimbs, larger toe pads - have to be passed on to their offspring. So we're going back this fall to measure the offspring produced by the surviving lizards."

While the URI scientist is confident the offspring of the surviving lizards will have many of the traits that made their parents successful at surviving hurricanes, there may be other factors at work pushing them to evolve in different - even opposite - ways.

"What's natural selection doing when there isn't a hurricane?" asked Kolbe. "What traits are favored under non-hurricane circumstances? Do their longer limbs now put them at a disadvantage? In between hurricanes, shorter limbs may be favored for moving around on the narrow vegetation."

It may take several generations of lizards and several years between hurricanes for all the questions to be answered. And even then, the expected increase in severe storms due to the changing climate will likely raise even more questions.

"In the past, when there has been a long period of time between hurricanes, the populations recover and natural selection might act to take them back to some optimal state for their environment," Kolbe said. "But if hurricanes keep hitting the island more frequently - making them more susceptible to extinction - selection may start to act in a back and forth fashion, and at some point they might not be able to respond effectively from an evolutionary sense.

"That's the bigger message," he added. "Most populations are experiencing multiple stressors - climate change, habitat change, invasive species - and all those changes are pulling populations in different directions. They might be able to adapt to one of those, but others are forcing them to adapt in another direction. They may end up using up all of their evolutionary fuel."

KINGSTON, R.I. - Aug. 16, 2018 - In 2008, a contaminant eluded the quality safeguards in the pharmaceutical industry and infiltrated a large portion of the supply of the popular blood thinner heparin, sickening hundreds and killing about 100 in the U.S.

It took a team of researchers led by the U.S. Food and Drug Administration to confirm the contaminant, a toxin structurally similar to heparin that was traced to a Chinese supplier. But detection of the impurity required "a tremendous effort by heavy hitters in the chemistry world," said Jason Dwyer, associate professor of chemistry at the University of Rhode Island.

After nearly eight years of research, Dwyer has developed a simpler and quicker method for detecting the impurity in heparin, along with creating a process that could have wider benefits. His research was unveiled today in the prestigious online journal Nature Communications, part of the suite of journals from the publisher of Nature.

"There are tests that are much more sophisticated and expensive to detect the impurity," said Dwyer, of Providence, R.I. "What we were able to do is - in a very inexpensive and rapid fashion - fingerprint heparin and tell when there is a contaminant in it."

The research, "Surveying Silicon Nitride Nanopores for Glycomics and Heparin Quality Assurance," could also be used to analyze the entire class of molecules to which heparin belongs with broad use in biomedical diagnostics, pharmaceuticals and environmental sensing. Dwyer's wider studies of sugars were bolstered in July by a $318,000 grant from the National Science Foundation.

For example, Dwyer said, the new detection technique could serve as a quality assurance tool across the pharmaceutical industry, especially with an increased push to develop more sugar-based drugs, such as heparin. "Sugars are incredibly important," said Dwyer, whose research in the past has garnered publication in the high-profile journals Nature and Science. "They're how bacteria communicate with each other. They're how we're going to be designing a lot of new drugs. So we need new tools to analyze sugars."

To develop the new detection technique, Dwyer turned to a sensing method proven in the sequencing of DNA and proteins. The sensor consists of a hole, or nanopore, less than a thousandth the thickness of a human hair, sitting on a membrane that is even thinner, and tests substances at the smallest detectable level - a single molecule.

While the sensor, a solid-state silicon nitride nanopore, worked well for DNA, it had to be retooled for sugar molecules, which are far more complex, said Dwyer, whose group was one of the first to focus on sugars.

Starting in 2010, the project developed along with other work by Dwyer's team. It took years to fabricate and fine-tune devices, refine the nanopore and prevent the opening from clogging. "A fair number of students have worked on this project over the years," Dwyer said. "We have not relented. We butted our heads against the wall for a period of time and we realized we needed to do a fair amount of fundamental work before we could get to the point of detecting."

One unexpected problem was solved by Buddini Karawdeniya, lead author of the paper who completed her doctorate in chemistry at URI in the spring. When she attempted to run sugar molecules through the nanopore, they went backwards. "In 1996, people figured out how DNA could be sensed with a nanopore," Dwyer said. "There were some oddities but it worked the way it was expected. Sugars right off the bat did not act as expected. So Buddini had to look at what had been done for 20 years, but know she had to start over at some level."

With the 2008 crisis, researchers had managed to identify and detect the oversulfated chondroitin sulfate contaminant, which was nearly identical to the heparin. Using the fine-tuned nanopore, Dwyer's research looked at both samples, determined that the signals they generated were 99-percent identical, and devised analysis techniques to use the 1-percent difference to reliably detect the impurity.

"The test we came up with takes about 20 minutes," he said, "and works at clinically relevant concentrations."

The goal is to make detection of the impurity even quicker, down to minutes and seconds. At the same time, the device will have to be adapted for a commercial user who may lack the expertise of a researcher in a technology development lab. Also, the tool would have to perform accurately in a less-controlled environment.

"This is where research starts to transition into development, and we start to refine the conditions and the devices even more," Dwyer said. "Often discovery is the easiest part. Refining it for the end user takes time."

The nanopore that came out of the heparin research was designed with that in mind. It uses technology similar to that found in nearly every piece of consumer electronics, said Dwyer, so there is already an industry ready to produce the sensors on a large scale.

"We always try to think about the consumer market," he said. "What we do in the lab is one thing -- and it is a vital thing -- but how do we translate it into the real world?"

Scientists have confirmed that the 3.4 billion year old Strelley Pool microfossils had chemical characteristics similar to modern bacteria. This all but confirms their biological origin and ranks them amongst the world's oldest microfossils. The work is presented at the Goldschmidt geochemistry conference in Boston, with simultaneous publication in the peer-reviewed journal Geochemical Perspectives Letters (see below for reference).

A team of scientists, led by Dr Julien Alleon (IMPMC, Paris, France; and MIT, Cambridge, MA, USA) have been able to show that the chemical residuals from ancient microfossils match those of younger bacterial fossils, and so are likely to have been laid down by early life forms.

They compared the results of synchrotron-based X-ray absorption spectroscopy analysis of the Strelley Pool microfossils with more recent ones from the Gunflint Formation (1.9 billion years old, found on the shores of Lake Superior, Ontario, Canada) and with modern bacteria.
All showed similar absorption features, indicating that the residual chemicals were made from the same building blocks, thereby supporting a biological origin (see illustration below).

Dr Jullien Alleon said:

"There are a couple of important points which come out of this work. Firstly, we demonstrate that the elemental and molecular characteristics of these 3.4 Ga microfossils are consistent with biological remains, slightly degraded by fossilization processes. This effectively supports the biological origin of the Strelley Pool microfossils. There are competing claims over which microfossils are actually the world's oldest, this analytical strategy needs to be applied to other ancient samples to help settle the controversy.

Secondly, it is remarkable that these echoes of past life have survived the extreme conditions they have experienced over the last 3.4 billion years: we know from the molecular structure of the microfossils that they have been exposed to temperatures of up to 300 °C for long periods. And yet we are still able to see signs of their original chemistry.

This is a step forward to confirming that these are indeed the oldest fossils yet discovered."

Commenting, Professor Vickie Bennett (Australian National University) said:

"This is exciting work with the new types of analyses providing compelling evidence that the cherts contain biogenic microfossils. This is in line with other observations for early life from the Strelley Pool rocks, including stromatolites interpreted as microbial mats, and further confirming that the minimum age for life on Earth is 3.4 billion years.

The techniques used here are not applicable to the older rocks that host the claims for the oldest terrestrial life, as these rocks were exposed to much higher temperatures. These samples include the 3.7 billion year old stromatolites from Isua, Greenland and the 4.1 billion year old Canadian microfossils. However, this work shows how quickly the field is developing and that new capabilities for testing and confirming earlier evidence of life are in reach".

Fragility fractures are a serious yet neglected complication of both type 1 and type 2 diabetes, with increased risk of fragility fractures in people with diabetes extending across the life span.

This is a concern as, globally, the prevalence of diabetes in adults is expected to increase from almost 425 million today, to approximately 629 million by 2045. At the same time, many clinicians who treat patients with diabetes are not aware of their patients' heightened risk of disabling and potentially life-threatening fractures.

Given this scenario, the International Osteoporosis Foundation (IOF) Bone and Diabetes Working Group has published a new expert review that summarizes key research, highlights clinical issues, and provides a helpful 'decision-tree' style algorithm for the identification and management of diabetic patients at increased fracture risk.

Download: Diagnosis and management of bone fragility in diabetes: an emerging challenge

Professor Serge Ferrari, chair of the IOF Committee of Scientific Advisors and of the IOF Bone and Diabetes Working Group, stated:

"The link between diabetes and skeletal health is complex and the optimal approach to the management of bone health in patients with diabetes is not yet definitive and may change over time as findings of new clinical studies become available. This new review will inform clinicians about the current state of knowledge, and, importantly, the clear algorithm will facilitate the clinical assessment and management of fragility fracture risk in their patients according to current best practice."

The review outlines the clinical characteristics of bone fragility in adults with diabetes, and highlights recent studies that have evaluated bone mineral density (BMD), bone microstructure and material properties, biochemical markers, and fracture prediction (FRAX). It also looks at the impact of diabetes drugs on bone, as well as the efficacy of osteoporosis treatments in these patients.

Key messages include:

The pathophysiology of bone fragility in diabetes is likely multifactorial.

FRAX and BMD T-score predict fracture risk in those with type 2 diabetes, but both require adjustment for diabetes to avoid underestimation of risk.

If a patient has indication for therapy based on criteria developed for non-diabetes patients, these patients should be treated with osteoporosis drugs. In the absence of established osteoporosis, these medications may be used, although with caution as the effects of these drugs in situations where bone fragility is mainly due to alterations in bone quality remain to be thoroughly evaluated.

Future studies should continue to evaluate the structural determinants (microstructure, material properties, etc.) of bone fragility and refine fracture prediction algorithms by including disease-specific determinants of fracture.

New trials will have to prospectively investigate the efficacy and safety of osteoporosis treatment in diabetics with and without low aBMD.

Researchers have developed a new method that aids in the process of making valuable compounds by using a unique combination of catalysts.

A study published in Nature reported a new catalytic method that combines enzymatic catalysts with photocatalysts.

Huimin Zhao, Professor of Chemical and Biomolecular Engineering and leader of the Biosystems Design research theme at the Carl R. Woese Institute for Genomic Biology at the University of Illinois, led the research alongside John Hartwig, Professor of Chemistry at the University of California, Berkeley, who was previously a professor at the University of Illinois and is a longtime collaborator of Zhao's. Coauthors include Yajie Wang, a graduate student in the department of chemical and biomolecular engineering at the University of Illinois, and Zachary Litman, a postdoctoral research fellow at the University of Michigan.

All organisms rely on chemical reactions in order to make various natural products. Chemical reactions can be caused by a number of catalysts, such as enzymatic or chemical catalysts.

Scientists often use combinations of enzymatic and chemical catalysts to cause reactions that result in higher yields than what can be achieved with enzymes alone. Higher yields are beneficial when scientists want to use these reactions to make useful products such as biofuels and pharmaceuticals.

But combining enzymatic and chemical catalysts is difficult to do -- the two catalysts aren't naturally compatible; they work best under different conditions and temperatures.

Seeing the need for new approaches, Wang and Litman came up with an idea: to combine enzymatic catalysis and photocatalysis.

Photocatalysis, which uses light to spur on a chemical reaction, is currently a popular research area.

"Lots of researchers have tried to develop new photocatalysts for different reactions," Zhao said. "And enzyme catalysis is a relatively old field."

While photocatalysis and enzyme catalysis have been studied separately, few researchers have put these two catalysts together.

The team studied several enzymes and photocatalysts and found a pair that works together.

"If you use a light-driven process instead of one driven by heat, then that will be compatible with the enzymes," Hartwig said.

They not only showed that enzymatic catalysts and photocatalysts can be combined, but that this combination can also be productive. Their method was able to create a few important active pharmaceutical intermediates (APIs) for producing pharmaceutical drugs.

"(This research) would be quite useful for synthetic chemistry," Hartwig said.

Zhao said they will pursue further research in this area as a part of Illinois' Center for Advanced Bioenergy and Bioproducts Innovation (CABBI), a collaboration between the Carl R. Woese Institute for Genomic Biology and the Institute for Sustainability, Energy, and Environment.

One of CABBI's goals is to engineer biological systems that produce non-natural compounds, which can be used for biofuels, jet fuels, lubricants, and more.

The researchers hope to find more combinations of photocatalysts and enzymatic catalysts for more chemical reactions.

"This is just a first example," Zhao said. "We want to find more chemoenzymatic systems for different types of reactions."

Zhao expects this research will also inspire new discoveries.

"There are many new photocatalysts for different types of reactions, and there are many enzymes," he said. "So I can see that this will stimulate researchers to develop new systems that can combine these two types of catalysts for making a wide variety of useful compounds."

Low-carb diets that replace carbohydrates with proteins and fats from plant sources associated with lower risk of mortality compared to those that replace carbohydrates with proteins and fat from animal sources.

Eating carbohydrates in moderation seems to be optimal for health and longevity, suggests new research published in The Lancet Public Health journal.

The observational study of more than 15,400 people from the Atherosclerosis Risk in Communities Study (ARIC) in the USA found that diets both low (70% energy) in carbohydrates were linked with an increase in mortality, while moderate consumers of carbohydrates (50-55% of energy) had the lowest risk of mortality.

The primary findings, confirmed in a meta-analysis of studies on carbohydrate intake including more than 432,000 people from over 20 countries, also suggest that not all low-carbohydrate diets appear equal--eating more animal-based proteins and fats from foods like beef, lamb, pork, chicken and cheese instead of carbohydrate was associated with a greater risk of mortality. Alternatively, eating more plant-based proteins and fats from foods such as vegetables, legumes, and nuts was linked to lower mortality.

"We need to look really carefully at what are the healthy compounds in diets that provide protection", says Dr Sara Seidelmann, Clinical and Research Fellow in Cardiovascular Medicine from Brigham and Women's Hospital, Boston, USA who led the research.

"Low-carb diets that replace carbohydrates with protein or fat are gaining widespread popularity as a health and weight loss strategy. However, our data suggests that animal-based low carbohydrate diets, which are prevalent in North America and Europe, might be associated with shorter overall life span and should be discouraged. Instead, if one chooses to follow a low carbohydrate diet, then exchanging carbohydrates for more plant-based fats and proteins might actually promote healthy ageing in the long term."[1]

Previous randomised trials have shown low carbohydrate diets are beneficial for short-term weight loss and improve cardiometabolic risk. However, the long-term impact of carbohydrate restriction on mortality is controversial with prospective research so far producing conflicting results. What's more, earlier studies have not addressed the source or quality of proteins and fats consumed in low-carb diets.

To address this uncertainty, researchers began by studying 15,428 adults aged 45-64 years from diverse socioeconomic backgrounds from four US communities (Forsyth County, NC; Jackson, MS; Minneapolis, MN; and Washington County, MD) enrolled in the ARIC cohort between 1987 and 1989. All participants reported consuming 600-4200 kcal per day for men and 500-3600 kcal per day for women, and participants with extreme (high or low) caloric intake were excluded from the analysis.

At the start of the study and again 6 years later, participants completed a dietary questionnaire on the types of food and beverages they consumed, what portion size and how often, which the researchers used to estimate the cumulative average of calories they derived from carbohydrates, fats, and protein.

The researchers assessed the association between overall carbohydrate intake (categorised by quantiles) and all cause-mortality after adjusting for age, sex, race, total energy intake, education, exercise, income level, smoking, and diabetes. During a median follow-up of 25 years, 6283 people died.

Results showed a U-shape association between overall carbohydrate intake and life expectancy, with low (less than 40% of calories from carbohydrates) and high (more than 70%) intake of carbohydrates associated with a higher risk of mortality compared with moderate intake (50-55% of calories).

The researchers estimated that from age 50, the average life expectancy was an additional 33 years for those with moderate carbohydrate intake--4 years longer than those with very low carbohydrate consumption (29 years), and 1 year longer compared to those with high carbohydrate consumption (32 years). However, the authors highlight that since diets were only measured at the start of the trial and 6 years later, dietary patterns could change over 25 years, which might make the reported effect of carbohydrate consumption on lifespan less certain.

In the next step of the study, the authors performed a meta-analysis of data from eight prospective cohorts (including ARIC) involving data from 432,179 people in North American, European, and Asian countries. This revealed similar trends, with participants whose overall diets were high and low in carbohydrates having a shorter life expectancy than those with moderate consumption (figure 2).

As Seidelmann explains, "A midrange of carbohydrate intake might be considered moderate in North America and Europe where average consumption is about 50% but low in other regions, such as Asia, where the average diet consists of over 60% carbohydrates." [1]

In further analyses examining whether the source of proteins and fats favoured in low-carbohydrate diets--plant-based or animal-based--was associated with length of life, researchers found that replacing carbohydrates with protein and fat from animal sources was associated with a higher risk of mortality than moderate carbohydrate intake. In contrast, replacing carbohydrates with plant-based foods was linked to a lower risk of mortality (table 3).

"These findings bring together several strands that have been controversial. Too much and too little carbohydrate can be harmful but what counts most is the type of fat, protein, and carbohydrate," says Walter Willett, Professor of Epidemiology and Nutrition at Harvard T. H. Chan School of Public Health and co-author of the study. [1]

The findings show observational associations rather than cause and effect. Considering evidence from other studies, the authors speculate that Western-type diets that heavily restrict carbohydrates often result in lower intake of vegetables, fruit, and grains and lead to greater consumption of animal proteins and fats--some of which have been implicated in stimulating inflammatory pathways, biological ageing, and oxidative stress--and could be a contributing factor to the increased risk of mortality. Whilst high carbohydrate diets (common in Asian and less economically advantaged nations) tend to be high in refined carbohydrates such as white rice, may also contribute to a chronically high glycaemic load and worse metabolic outcomes.

"This work provides the most comprehensive study of carbohydrate intake that has been done to date, and helps us better understand the relationship between the specific components of diet and long term health", says Dr Scott Solomon, The Edward D Frohlich Distinguished Chair at Brigham and Women's Hospital and Professor of Medicine at Harvard Medical School, and senior author on the paper. "While a randomized trial has not been performed to compare the longer term effects of different types of low carbohydrate diets, these data suggest that shifting towards a more plant-based consumption is likely to help attenuate major morbid disease."[1]

The authors note some limitations including that dietary patterns were based on self-reported data, which might not accurately represent participants' food consumption; and that their conclusions about animal-based sources of fat and protein might have less generalisability to Asian populations which tend to have diets high in carbohydrates, but often consume fish rather than meat. Finally, given the relatively small number of individuals following plant-based low-carb diets, further research is needed.

Writing in a linked Comment, Dr Andrew Mente and Dr Salim Yusuf from McMaster University, Hamilton, Canada say, "Such differences in risk associated with extreme differences in intake of a nutrient are plausible, but observational studies cannot completely exclude residual confounders when the apparent differences are so modest. Based on first principles, a U-shaped association is logical between most essential nutrients versus health outcomes. Essential nutrients should be consumed above a minimal level to avoid deficiency and below a maximal level to avoid toxicity. This approach maintains physiological processes and health (ie, a so-called sweet spot). Although carbohydrates are technically not an essential nutrient (unlike protein and fats), a certain amount is probably required to meet short-term energy demands during physical activity and to maintain fat and protein intakes within their respective sweet spots. On the basis of these principles, moderate intake of carbohydrate (eg, roughly 50% of energy) is likely to be more appropriate for the general population than are very low or very high intakes."

Arlington, Va., August 16, 2018 - The consequences of healthcare-associated infections (HAIs) reach well beyond patients' physical health, souring social relationships, and leading some healthcare providers (HCP) to distance themselves from affected patients, according to a qualitative, systematic review published in the American Journal of Infection Control (AJIC), the journal of the Association for Professionals in Infection Control and Epidemiology (APIC).

To properly address patients' needs and concerns, researchers at Glasgow Caledonian University in Scotland, and colleagues, conducted a meta-synthesis of qualitative research, looking at 17 studies from five different countries addressing five common types of HAIs, focusing on patient experiences of both colonization and infection from bacteria that commonly cause HAIs.

The authors of this meta-synthesis urge HCP to consider the social circumstances that color patient experiences, including feeling shameful and dirty, and the responses of those around them, especially those of HCP.

According to the analysis, many patients experienced an emotional response to their diagnosis and described "feeling dirty," "having the plague," or "feeling like a leper." While emotional responses varied based on type of HAI, patients with nearly all colonization or infection types reported a fear of transmitting their infection to others. This fear affected patients' personal and workplace relationships. Some patients, particularly those colonized by MRSA, also expressed concern about working in certain professions because of their condition and a fear of rejection by coworkers.

Patients who were able to speak to infection preventionists reported receiving constructive information and feeling reassured about their condition, whereas patients who did not, reported feeling dismissed by staff members.

"Having an HAI is a significant event in the patient's care journey and subsequent life that is influenced by biology, society and context," said Kay Currie, PhD, the paper's lead author. "Understanding the patient experience can help HCP to interact and respond in a constructive way, providing more effective support during this challenging time in a patient's healthcare experience."

The analysis also found:

Concerns about interaction with HCP or restriction to healthcare treatment were particularly prominent among patients with infections caused by resistant organisms, such as methicillin-resistant Staphylococcus aureus (MRSA) or Extended-Spectrum Beta-lactamases (ESBL). The studies highlight patient reports of exclusion from rehabilitation classes, requirements to wait until the end of clinic appointments to be seen, or restrictions on attending clinics.

Many patients with HAIs reported changing their personal hygiene behavior, taking precautions to prevent the transmission of infection, including undergoing extensive cleaning at home and advising family members on hygiene measures.

Many patients reported interactions in a climate that induced fear and uncertainty, particularly when frontline HCP lacked knowledge of the causes and consequences of HAIs and could not provide the patient with adequate information. This finding highlighted the sociocultural context in which the infection or colonization occurs.

"As one in every 25 hospitalized patients in the United States is diagnosed with an HAI, it is critical to understand the long-lasting impact of such infections, not just from a physical perspective, but also from a social and emotional perspective," said 2018 APIC President Janet Haas, PhD, RN, CIC, FSHEA, FAPIC. "This qualitative review provides valuable insight into the patient perspective and how healthcare professionals can more effectively interact with their patients to enhance recovery in all areas of their lives."

GALVESTON, Texas - A new study from The University of Texas Medical Branch at Galveston has uncovered why some people that have brain markers of Alzheimer's never develop the classic dementia that others do. The study is now available in the Journal of Alzheimer's Disease.

Alzheimer's disease, the most common form of dementia, affects more than 5 million Americans. People suffering from Alzheimer's develop a buildup of two proteins that impair communications between nerve cells in the brain - plaques made of amyloid beta proteins and neurofibrillary tangles made of tau proteins.

Intriguingly, not all people with those signs of Alzheimer's show any cognitive decline during their lifetime. The question became, what sets these people apart from those with the same plaques and tangles that develop the signature dementia?

"In previous studies, we found that while the non-demented people with Alzheimer's neuropathology had amyloid plaques and neurofibrillary tangles just like the demented people did, the toxic amyloid beta and tau proteins did not accumulate at synapses, the point of communication between nerve cells," said Giulio Taglialatela, director of the Mitchell Center for Neurodegenerative Diseases. "When nerve cells can't communicate because of the buildup of these toxic proteins that disrupt synapse, thought and memory become impaired. The next key question was then what makes the synapse of these resilient individuals capable of rejecting the dysfunctional binding of amyloid beta and tau?"

In order to answer this question, the researchers used high-throughput electrophoresis and mass spectrometry to analyze the protein composition of synapses isolated from frozen brain tissue donated by people who had participated in brain aging studies and received annual neurological and neuropsychological evaluations during their lifetime. The participants were divided into three groups - those with Alzheimer's dementia, those with Alzheimer's brain features but no signs of dementia and those without any evidence of Alzheimer's.

The results showed that resilient individuals had a unique synaptic protein signature that set them apart from both demented AD patients and normal subjects with no AD pathology. Taglialatela said that this unique protein make-up may underscore the synaptic resistance to amyloid beta and tau, thus enabling these fortunate people to remain cognitively intact despite having Alzheimer's-like pathologies.

"We don't yet fully understand the exact mechanism(s) responsible for this protection," said Taglialatela. "Understanding such protective biological processes could reveal new targets for developing effective Alzheimer's treatments."

On Avoiding Deep Dementia
Norman L. Cantor

To avoid prolonged dementia, the author has written an advanced directive to prohibit the provision of life-sustaining interventions, including hydration and nutrition, should he reach a self-defined point of cognitive debilitation. But if that point is reached, he would be unable to comprehend the reasoning that motivated the advanced directive, and he might enjoy life despite having dementia. Still, surrogate decision-makers and caregivers would have a moral and legal obligation to implement his advanced directive, argues Cantor, a professor emeritus of law at Rutgers University School of Law. Competent individuals should be given control over directing the types of life-sustaining treatments they receive if they develop dementia.

Other Voices: Three commentaries raise concerns about advance directives that limit care for people with dementia.

Are Obese Children Abused Children?
Maura Priest

In 2010, a South Carolina mother was charged with criminal neglect after her 14-year-old son reached 555 pounds, in the first U.S. felony case involving childhood obesity. But this article discusses important ethical and legal distinctions between negligent and abusive caretakers and caretakers of obese children. The former intentionally harm or fail to protect the children under their care, while caretakers of obese children may act in well-intentioned though misguided ways. And environmental, social, and genetic factors are also significant contributors to childhood obesity. Since allowing a child to become obese falls into a different moral and legal category from abusing or neglecting a child, the solutions to protect obese children must be different from those to protect abuse and neglect victims. Priest is an assistant professor of philosophy at Arizona State University and an affiliate researcher at the University of Cologne.

Discriminatory Demands by Patients
Philip M. Rosoff

Many in health care are concerned, even appalled, when patients demand physicians, nurses, and other caregivers of a particular gender or race. While there is evidence that patients from groups that have been victims of discrimination may have better health outcomes if they have clinicians of the same background or gender, how does one distinguish requests that are potentially beneficial from those that are simply discriminatory? Which requests should be honored, and which should be denied? The answers are not straightforward, writes Philip M. Rosoff, a professor of pediatrics and medicine at Duke University School of Medicine and an adjunct professor of clinical science at North Carolina State University College of Veterinary Medicine.