Brain

HOUSTON - (May 17, 2021) - In an important step toward the clinical application of synthetic biology, Rice University researchers have engineered a bacterium with the necessary capabilities for diagnosing a human disease.

The engineered strain of the gut bacteria E. coli senses pH and glows when it encounters acidosis, an acidic condition that often occurs during flareups of inflammatory bowel diseases like colitis, ileitis and Crohn's disease.

Researchers at the University of Colorado (CU) School of Medicine used the Rice-created organism in a mouse model of Crohn's disease to show acidosis activates a signature set of genes. The corresponding genetic signature in humans has previously been observed during active inflammation in Crohn's disease patients. The results are available online in the Proceedings of the National Academy of Sciences.

Study co-author Jeffrey Tabor, whose lab engineered the pH-sensing bacterium, said it could be reprogrammed to make colors that show up in the toilet instead of the fluorescent tags used in the CU School of Medicine experiments.

"We think it could be added to food and programmed to turn toilet water blue to warn patients when a flareup is just beginning," said Tabor, an associate professor of bioengineering in Rice's Brown School of Engineering.

Over their 3.5 billion-year history, bacteria have evolved countless specific and sensitive genetic circuits to sense their surroundings. Tabor and colleagues developed a biohacking toolkit that allows them to mix and match the inputs and outputs of these bacterial sensors. The pH-sensing circuit was discovered by Rice Ph.D. student Kathryn Brink in a 2019 demonstration of the plug-and-play toolkit.

PNAS study co-authors Sean Colgan, the director of the CU School of Medicine's mucosal inflammation program, and Ian Cartwright, a postdoctoral fellow in Colgan's lab, read about the pH sensor and contacted Tabor to see if it could be adapted for use in a mouse model of Crohn's disease.

"It turns out that measuring pH within the intestine through noninvasive ways is quite difficult," said Colgan, the Levine-Kern Professor of Medicine and Immunology in the CU School of Medicine.

So Brink spent a few weeks splicing the necessary sensor circuits into an organism and sent it to Colgan's lab.

"Normally, the pH in your intestines is around seven, which is neutral, but you get a lot of inflammation in Crohn's disease, and pH goes to something like three, which is very acidic," Tabor said.

Colgan and colleagues have studied the genes that are turned on and off under such conditions and "needed a tool to measure pH in the intestine to show that the things they were observing in in vitro experiments were also really happening in a live animal," Tabor said.

"Colonizing this bacterial strain was the perfect biological tool to monitor acidosis during active inflammation," Colgan said. "Correlating intestinal gene expression with the bacterial pH sensing bacteria proved to be a useful and valuable set of biomarkers for active inflammation in the intestine."

Tabor said he believes the pH-sensing bacterium could potentially be advanced for human clinical trials in several years.

Tabor's work was supported by the Welch Foundation (C-1856) and the National Science Foundation (1553317).

University researchers have carried out the largest systematic review and meta-analysis to date of how people's perceptions of their screen time compare with what they do in practice, finding estimates of usage were only accurate in about five per cent of studies.

The international team say this casts doubt on the validity of research on the impact of screen time on mental health, and its influences on government policy, as the vast majority rely on participants to estimate (self-report) how long they spend on digital devices, rather than logs of actual usage, or tracked time.

"For decades, researchers have relied on estimates of how we use various technologies to study how people use digital media and the potential outcomes this behaviour can lead to. Our findings suggest that much of this work may be on unstable footing," said lead researcher Dr Doug Parry at Stellenbosch University.

"The screen time discrepancies highlight that we simply do not know enough yet about the actual effects (both positive and negative) of our media use. Researchers, journalists, members of the public, and crucially policy makers need to question the quality of evidence when they consider research on media uses and effects. We can no longer simply take claims of harmful effects at face value."

The researchers also investigated whether questionnaires and scales addressing 'problematic' media use, such as excessive or so-called 'addictive' media use, were suitable substitutes for logged usage. They found an even smaller association with usage logs for these measures.

Published in Nature Human Behaviour, the research identified every existing study that compares logged or tracked media use measures with equivalent self-reports. They screened over 12,000 articles for inclusion and found 47 studies that included both types of measures. From here they were able to identify and extract 106 comparisons, based on 50,000 individuals, to address the question of how closely self-report estimates relate to logs of actual usage.

"These highly flawed studies are over-inflating the relationships between digital media use and typically negative outcomes, such as mental health symptoms and cognitive impairments, which of course explains the pervading view that smartphones among other technologies are bad for us," said Dr Brit Davidson from the University of Bath's School of Management.

"Media and technology use takes the blame for everything from increases in teenage depression and suicide to higher incidence of Attention Deficit Hyperactivity Disorder (ADHD) and violence. If we want to properly investigate harms, we must first tackle assumptions about screen time and disentangle how people are actually using their phones or other technologies of interest.

"Importantly, these questionable studies are also being used to influence policy. The UK and Canada both have forms of screen time guidelines based on poorly conducted research, which is clearly worrying and hard to reverse."

The research team also included Dr Craig Sewall at The University of Pittsburgh; Dr Jacob Fisher at the University of Illinois Urbana-Champaign; Hannah Mieczkowski at Stanford University; and Dr Daniel Quintana at the University of Oslo.

The researchers hope that their study will lead to a shift in measurement practices regarding technology, alongside starting to correct the narrative regarding technology and society. They say that only by better understanding what people actually do with their technologies, can we start to genuinely understand the impact of them on people and society.

A systematic review and meta-analysis of discrepancies between logged and self-reported digital media use is published by Nature Human Behaviour:

Patients at high risk for cardiovascular events who had the highest levels of eicosapentaenoic acid (EPA) in their blood one year after taking daily omega-3 carboxylic acid, a prescription-grade fish oil, had similar rates of major cardiovascular events as people taking a corn oil placebo, according to a secondary analysis of the STRENGTH trial presented at the American College of Cardiology's 70th Annual Scientific Session. Researchers also found no increase in cardiovascular events among patients with the highest levels of docosahexaenoic acid (DHA) compared to placebo.

The impetus for this post-hoc analysis was to further examine the strikingly divergent results between STRENGTH and REDUCE-IT, another large, randomized clinical trial that used a different omega-3 fatty acid formulation (icosapent ethyl, purified EPA only) and mineral oil as the placebo.

"This is an intensely controversial area. One fish oil trial after another has been neutral, but REDUCE-IT reported a striking 25% reduction in events compared with a placebo pill containing mineral oil. But in our analysis, among patients treated with fish oil we found no evidence that EPA is beneficial or that DHA is harmful," said Steven Nissen, MD, MACC, cardiologist at Cleveland Clinic and the study's lead author. "So, we have many patients taking fish oils but no evidence that they have favorable effects on the heart."

The double-blind, multicenter STRENGTH trial enrolled 13,078 people at high risk for major cardiovascular events from 675 sites in 22 countries between Oct. 30, 2014 and June 14, 2017. Patients were randomized to receive either four grams daily of omega-3 carboxylic acid (a combination of EPA and DHA) or corn oil as the placebo. As previously reported, researchers found no difference between the two groups in terms of the primary outcome--a composite of cardiovascular death, heart attack, stroke, need for procedures to open blocked arteries or chest pain that required hospitalization.

This remained true in the current analysis, which examined a subset of 10,382 patients (5,175 receiving omega-3 carboxylic acid and 5,207 in the corn oil group) with available omega-3 fatty acid levels. Events occurred in 11.1% of patients treated with fish oil and 11% of patients in the placebo group. Overall, this group of patients was 62.5 years old on average, one-third were women and another third had diabetes.

Researchers grouped patients into thirds (tertiles) based on achieved EPA and DHA levels assessed through bloodwork at baseline and 12 months after randomization. The median plasma EPA level for patients taking fish oil was 89 (46-131) μg/mL and 91 (71-114) μg/mL for DHA, with the top tertile achieving levels of 151 (132-181) and 118 (102-143) μg/mL, respectively.

Researchers found no difference in the occurrence of the prespecified primary outcome among patients treated with omega-3 carboxylic acid who were in the top tertile of achieved EPA levels at one year compared with events seen in patients treated with corn oil; the event rate was 11.3% and 11%, respectively. For the top tertile of achieved DHA, the event rate was 11.4%. Researchers said they would have expected to see a difference in events among these patients if higher levels of EPA have a protective role. Further analyses examined changes in EPA or DHA over time and similarly showed neutral effects on cardiovascular outcomes.

"To be thorough, we looked at the data multiple ways--absolute EPA and DHA levels, change in levels of these omega-3 fatty acids, red blood cell levels, and by primary and secondary prevention subgroups," Nissen said. "All of these analyses showed no benefits or harms."

Nissen said there are several possible reasons for the very different results emerging from the STRENGTH and REDUCE-IT trials.

"It could be that EPA really is beneficial or it could be that the administration of DHA in STRENGTH could have caused harm, thereby undermining the benefits of EPA; however, the current study found no benefit from EPA and no harm from DHA," he said. "Alternatively, the differing results from these studies could have occurred because REDUCE-IT used mineral oil as the placebo, resulting in a false positive trial. Unlike corn oil, which is inert, mineral oil has major adverse effects. If you give a toxic placebo, then the active drug may look really good."

In the STRENGTH trial, the top tertile of achieved median EPA level was 151 μg/mL, which compares favorably with the median level reported in the REDUCE-IT trial (144 μg/mL).

Nissen said that if there is no benefit of fish oil in preventing major cardiovascular events, the potential harms must then be considered. Although the absolute numbers were small, there was a 69% increase in new onset atrial fibrillation, a dangerous heart rhythm disorder, among individuals taking fish oil, which occurred in 2.2% of patients in the fish oil group compared with 1.3% of those taking corn oil.

"Fish oils increase the risk of atrial fibrillation substantially, and there is no solid evidence that they help the heart in anyway," Nissen said. "It's a sad story for cardiology."

A key limitation of the study is that it is a post-hoc analysis.

Monash University researchers have validated a way to successfully detect a diverse range of bacteria (pathogens) that cause diarrhoeal disease in informal settlements.

Better protection from disease for people living in communities facing water, sanitation and hygiene challenges is essential, as microbes that cause gastrointestinal disease (enteropathogens) are responsible for 1.4 million deaths per year, predominantly in children under five, and cause impaired nutrition and development.

However, it is highly challenging to effectively monitor their spread due to the sheer number of pathogens and sources involved. Numerous enteropathogens cause diarrhoea and other gastrointestinal diseases, spanning viruses, bacteria, amoeba, and worms, each with distinct characteristics. Moreover, they are spread through complex pathways via human, animal, environmental, and food sources. Traditionally, microbiologists only monitor select pathogens and each source is usually tested separately.

The study, published in The Lancet Planetary Health, evaluated for the first time the laboratory method called the TaqMan Array Card (TAC) against the gold standard method, standard quantitative polymerase chain reaction (qPCR). They found that the TAC is faster and cheaper than qPCR, while delivering comparably precise results and simultaneously detecting over 30 different enteropathogens.

Monash University's Biomedicine Discovery Institute microbiologist Dr Rachael Lappan co-led the comparative study using wastewater samples from Melbourne and human stool, animal scat, soil, and water samples from informal settlements in Suva, Fiji. She says that validating the TAC method is a big step forward in combating the complex and neglected problem of childhood diarrhoea.

'Enteropathogens can be picked up through so many different ways in informal settlements, and it can be a real challenge to monitor them because there's such a variety of enteropathogens that contribute to disease,' Dr Lappan explains. 'TAC offers a relatively simple and affordable way to do this, and it can be done on any kind of sample.'

'It's incredibly important because it will help us better understand and monitor the pathways through which people become sick, and help target those pathways with effective water management interventions that could ultimately lead to better health, like the one we are trialling in the Revitalising Informal Settlements and their Environments (RISE) program,' Dr Lappan said.

Co-senior author of the paper, Associate Professor Chris Greening from Monash University's Biomedicine Discovery Institute, adds 'by comparing these methods, we wanted to know whether the ability to efficiently detect a broad range of enteropathogens would come with a substantial disadvantage in sensitivity. However, we showed that TAC performs comparably to qPCR and is ideally suited for broad pathogen screening that is impractical to carry out via standard qPCR.'

The study was conducted as part of the Revitalising Informal Settlements and their Environments (RISE) program, an interdisciplinary research program and trial that aims to improve the management of water and sanitation in urban informal settlements with nature-based infrastructure. RISE, and other transformational water, sanitation and hygiene programs, need techniques that allow comprehensive but efficient monitoring of enteropathogens to understand environmental contamination and disease burden before and after interventions.

Better designed vaccines for insect-spread viruses like dengue and Zika are likely after researchers discovered models of immature flavivirus particles were originally misinterpreted.

Researchers from The University of Queensland and Monash University have now determined the first complete 3D molecular structure of the immature flavivirus, revealing an unexpected organisation.

UQ researcher Associate Professor Daniel Watterson said the team was studying the insect-specific Binjari virus when they made the discovery.

"We were using Australia's safe-to-handle Binjari virus, which we combine with more dangerous viral genes to make safer and more effective vaccines," Dr Watterson said.

"But when analysing Binjari we could clearly see that the molecular structure we've all been working from since 2008 wasn't quite correct.

"Imagine trying to build a house when your blueprints are wrong - that's exactly what it's like when you're attempting to build effective vaccines and treatments and your molecular 'map' is not quite right."

The team used a technique known as cryogenic electron microscopy to image the virus, generating high resolution data from Monash's Ramaciotti Centre for Cryo-Electron Microscopy facility.

With thousands of collected two-dimensional images of the virus, the researchers then combined them using a high-performance computing platform called 'MASSIVE' to construct a high-resolution 3D structure.

Monash's Associate Professor Fasséli Coulibaly, a co-leader of the study, said the revelation could lead to new and better vaccines for flaviviruses, which have a huge disease burden globally.

"Flaviviruses are globally distributed and dengue virus alone infects around 400 million people annually," Dr Coulibaly said.

"They cause a spectrum of potentially severe diseases including hepatitis, vascular shock syndrome, encephalitis, acute flaccid paralysis, congenital abnormalities and foetal death.

"This structure defines the exact wiring of the immature virus before it becomes infectious, and we now have a better understanding of the levers and pulleys involved in viral assembly.

"This is a continuation of fundamental research by us and others and, without this hard-won basic knowledge, we wouldn't have the solid foundation needed to design tomorrow's treatments."

High-precision noble gas analyses indicate that solar wind particles from our primordial Sun were encased in the Earth's core over 4.5 billion years ago. Researchers from the Institute of Earth Sciences at Heidelberg University have concluded that the particles made their way into the overlying rock mantle over millions of years. The scientists found solar noble gases in an iron meteorite they studied. Because of their chemical composition, such meteorites are often used as natural models for the Earth's metallic core.

The rare class of iron meteorites make up only five percent of all known meteorite finds on Earth. Most are fragments from inside larger asteroids that formed metallic cores in the first one to two million years of our Solar System. The Washington County iron meteorite now being studied at the Klaus Tschira Laboratory for Cosmochemistry at the Institute of Earth Sciences was found nearly 100 years ago. Its name comes from the location in Colorado (USA) where it was discovered. It resembles a metal discus, is six cm thick, and weighs approx. 5.7 kilograms, according to Prof. Dr Mario Trieloff, head of the Geo- and Cosmochemistry research group.

The researchers were finally able to definitively prove the presence of a solar component in the iron meteorite. Using a noble gas mass spectrometer, they determined that the samples from the Washington County meteorite contain noble gases whose isotopic ratios of helium and neon are typical for the solar wind. According to Dr Manfred Vogt, a member of the Trieloff team, "the measurements had to be extraordinarily accurate and precise to differentiate the solar signatures from the dominant cosmogenic noble gases and atmospheric contamination". The team postulates that solar wind particles in the primordial Solar System were trapped by the precursor materials of the Washington County parent asteroid. The noble gases captured along with the particles were dissolved into the liquid metal from which the asteroid's core formed.

The results of their measurements allowed the Heidelberg researchers to draw a conclusion by analogy that the core of the planet Earth might also contain such noble gas components. Yet another scientific observation supports this assumption. Prof. Trieloff's research group has long been measuring solar noble gas isotopes of helium and neon in igneous rock of oceanic islands like Hawaii and Réunion. These magmatites derive from a special form of volcanism sourced by mantle plumes rising from thousands of kilometres deep in the Earth's mantle. Their particularly high solar gas content makes them fundamentally different from the shallow mantle as represented by volcanic activity of submarine mid-ocean mountain ridges. "We always wondered why such different gas signatures could exist at all in a slowly albeit constantly convecting mantle," states the Heidelberg researcher.

Their findings appear to confirm the assumption that the solar noble gases in mantle plumes originate in the planet's core - and hence signify solar wind particles from the centre of the Earth. "Just one to two percent of a metal with a similar composition as the Washington Country meteorite in the Earth's core would be enough to explain the different gas signatures in the mantle," states Dr Vogt. The Earth's core may therefore play a previously underappreciated active role in the geochemical development of the Earth's mantle.

Eating a diet rich in fruit and vegetables is associated with less stress, according to new research from Edith Cowan University (ECU).

The study examined the link between fruit and vegetable intake and stress levels of more than 8,600 Australians aged between 25 and 91 participating in the Australian Diabetes, Obesity and Lifestyle (AusDiab) Study from Baker Heart and Diabetes Institute.

The findings revealed people who ate at least 470 grams of fruit and vegetables daily had 10 per cent lower stress levels than those who consumed less than 230 grams. The World Health Organization (WHO) recommends eating at least 400 grams of fruit and vegetables per day.

Lead researcher, PhD candidate Simone Radavelli-Bagatini from ECU's Institute for Nutrition Research, said the study strengthens the link between diets rich in fruit and vegetables and mental wellbeing.

"We found that people who have higher fruit and veggie intakes are less stressed than those with lower intakes, which suggests diet plays a key role in mental wellbeing," said Ms Radavelli-Bagatini.

A growing issue

Mental health conditions are an increasing problem in Australia and around the world. Around one in two Australians will experience a mental health issue in their lifetime. Globally, approximately 1 in 10 people live with a mental health disorder.

According to Ms Radavelli-Bagatini, some stress is considered normal, but long-term exposure can significantly impact mental health.

"Long-term and unmanaged stress can lead to a range of health problems including heart disease, diabetes, depression and anxiety so we need to find ways to prevent and possibly alleviate mental health problems in the future," said Ms Radavelli-Bagatini.

The benefits of a healthy diet are well known, but only 1 in 2 Australians eat the recommended two serves of fruit per day and fewer than 1 in 10 eat the recommended five serves of vegetables each day.

"Previous studies have shown the link between fruit and vegetable consumption and stress in younger adults, but this is the first time we're seeing similar results across adults of all ages," said Ms Radavelli-Bagatini.

"The study's findings emphasise that it's important for people to have a diet rich in fruit and vegetables to potentially minimise stress."

Food and mood

While the mechanisms behind how fruit and vegetable consumption influences stress are still unclear, Ms Radavelli-Bagatini said key nutrients could be a factor.

"Vegetables and fruits contain important nutrients such as vitamins, minerals, flavonoids and carotenoids that can reduce inflammation and oxidative stress, and therefore improve mental wellbeing," she said.

"Inflammation and oxidative stress in the body are recognised factors that can lead to increased stress, anxiety and lower mood."

"These findings encourage more research into diet and specifically what fruits and vegetables provide the most benefits for mental health."

The research is part of ECU's recently launched Institute for Nutrition Research, which aims to investigate how nutrition can help prevent and treat chronic health conditions.

'Fruit and vegetable intake is inversely associated with perceived stress across the adult lifespan' was published in Clinical Nutrition.

The relevance for radiology applications is probably the most known advantage of X-ray beams (keV energies) with respect to visible radiation (eV energies) and can be traced back to their superior penetration depth. On a more fundamental ground, however, the relevance of this photon energy range relies on the capability of probing inner shell electrons (as they have comparable binding energies) and mapping molecular structures on the atomic-scale (as typical interatomic spacings are comparable to X-ray wavelengths). Building on such capabilities, large efforts have been devoted by the scientific community to develop X-ray sub-picosecond sources able to access matter properties with a time resolution sufficient to access elemental molecular motions. Free electron lasers (FEL), nowadays available at several large-scale facilities around the world, represent a prime candidate to generate femtosecond X-ray pulses with high brilliance. One of the main challenges to exploit the enormous potential of FEL sources is developing methods for tuning the spectral and temporal beam properties, a task which is customarily achieved at visible wavelengths resorting to non-linear optics.

In a new paper published in Light Science & Application, a team of scientists from Italian Institute of Technology, University of L'Aquila, FERMI Trieste and "Sapienza" University of Rome have shown the first evidence of self-phase modulation (SPM) in the soft X-ray regime. The experiment, performed in the facility FERMI@elettra of Trieste, consists in the observation of spectral modulation after the interaction of focused FEL beams with a very thin metallic foil (100-300 nm).

"Our experiment demonstrates a new control knob for spectral shaping of FEL pulses. Blue to red shift accompanied by bandwidth increase can be obtained by moving the input wavelength across the material's absorption edge" prof. Tullio Scopigno explains.

The atomic absorption edges in the X-ray region feature sharp discontinuities: an optical transparent material can absorb light modifying the photon energy by less than 1%, correspondingly generating specific core electron excitations.

"This first observation of SPM effects in the soft X-Ray regime allows to unveil specific atomic properties on the subpicosecond time scale. In particular, the interplay with a light-induced out-of-equilibrium electron plasma generated on the femtosecond timescale in thin metallic foils." concludes Dr. Carino Ferrante.

Below the absorption edge, the observed SPM is induced by Kerr effect, i.e. by a modification of the non-linear refractive index mimicking the pulse intensity profile, which ultimately results into spectral broadening, accompanied by a redshift due to valence electrons heating. In striking difference, above edge, the highly excited core photoelectrons generated by the pulse leading edge form a transient hot dense ionized plasma, responsible for a sharp decrease of the refractive index. Consequently, the pulse trailing edge is accelerated giving rise to an asymmetric temporal compression which, in turn, results in a blueshift.

The results provide a proof of concept for spectral shaping of soft X-ray pulses, a key milestone towards the development of new protocols for femtosecond core electrons spectroscopies.

How people consume news and take actions based on what they read, hear or see, is different than how human brains process other types of information on a daily basis, according to researchers at the University of Missouri School of Journalism. While the current state of the newspaper industry is in flux, these journalism experts discovered people still love reading newspapers, and they believe a newspaper's physical layout and structure could help curators of digital news platforms enhance their users' experiences.

"Many people still love print newspapers, and to an extent, we also see that they like the digital replicas of print newspapers as much as they do the physical version," said Damon Kiesow, a professor of journalism professions and co-author on the study. "But we believe there is more to understanding this notion than just simply habit and experience. We feel newspapers are fulfilling some sort of need in a person's daily life that is not currently being effectively fulfilled with the digital experience. The contextual clues that help tell readers what stories are important, why they should care about what stories they are reading and where to locate the news that is most important to them, are being weakened by structures missing in digital news."

The study is based on psychologist James Gibson's theory of "affordances," which argues an object's properties indicate what desired action should be taken with the object. The researchers believe this theory can apply to print newspapers in the way that various surfaces, layout, colors and labels can help contextualize a news story and give it meaning to the reader. By conducting in-depth interviews with 12 long-time newspaper subscribers, the team was able to identify 10 affordances of people who read print newspapers. They are:

Physical affordances, or the ability to physically hold something, navigate a newspaper's defined sections and pages, and create a physical archive of multiple editions for later viewing.

Perceived affordances, or the ability to determine a story's importance, how visual elements are added for contextual purposes, to allow readers to express feelings of possession, and to allow readers to distinguish between different topics of interest.

Relational affordances, or the ability to generate trust, to allow the reader to either actively or passively seek information, and to allow for the discovery of unexpected information.

By better understanding these affordances, the researchers now believe print newspapers have moved to digital platforms without first having a proper understanding of how readers use printed contextual clues to make sense of the news. Kiesow, who has a background in human-computer interfaces, believes these affordances can help inform news organizations when making decisions on their digital platforms to deliver the day's news.

"There is a need for better understanding how print-centric workflows and publishing tools might be hampering readers' understanding of the news on digital platforms," Kiesow said. "Publishers should be looking at elements such as navigation and labels, but also how contextual signals are carried across platforms, including social media, where first impressions of what the news is about are often initially formed before a click occurs. What news organizations should be doing is testing and designing their digital platforms more for understanding, rather than just usability."

Shuhua Zhou, a professor of journalism studies and corresponding author on the study, focuses his research on how people learn from the news. He said Gibson's theory can help explain the many perceptions of the news that people have.

"Gibson has a beautiful theory to help explain whatever we do as human beings, that there are meanings that we assign to those actions," Zhou said. "His use of affordances focuses on what can be done, or the action-potential. Here, we can think about news consumption in a similar way. When a reader sees a headline, the style -- bold type and font size -- gives the news story some type of meaning to that person. That is the action-potential that Gibson refers to in his theory. So, by using this theoretical concept, it can help us better understand why people perceive the news in the way that they do. I think the problem with most newspaper websites is that they are built without thinking about the features which are conducive to readers taking in and making sense of information."

New Brunswick, N.J. (May 12, 2021) - A Rutgers study finds that symbiotic bacteria that colonize root cells may be managed to produce hardier crops that need less fertilizer.

The study appears in the journal Microorganisms.

Bacteria stimulate root hair growth in all plants that form root hairs, so the researchers examined the chemical interactions between bacteria inside root cells and the root cell.

They found that bacteria are carried in seeds and absorbed from soils, then taken into root cells where the bacteria produce ethylene, a plant growth hormone that makes root cells grow root hairs. When the root hair grows, it ejects some of the bacteria back into the soil, then the remaining bacteria in the root hairs replicate and trigger a growth spurt every 15 minutes until the hairs are fully developed.

Ethylene is also a stress hormone that causes plants to adapt and become more resistant to oxidative stresses, including heat, soil salt, heavy metals and stresses potentially caused by climate change.

The researchers found that ethylene triggers root cells to secrete superoxide onto bacteria in root cells, causing bacteria to produce nitric oxide that detoxifies the superoxide. Nitric oxide combines with superoxide to form nitrate that is absorbed by root cells. In this process, bacteria in root cells make root hairs grow and supply root cells with nitrogen and other nutrients.

"This matters because it shows that the microbiome of plants is important for plant cell development, particularly root cell development, and nutrient supply," said study co-author James White, a professor in the Department of Plant Biology in the School of Environmental and Biological Sciences at Rutgers University-New Brunswick. "Use of bacteria in plants may enable us to grow better developed and stress resistant crops that require less fertilizers, and thus will reduce environmental damage due to excess fertilizer applications with consequent runoff. Further, with the correct bacteria in crop plants, we may produce crops that are resistant to oxidative stresses stemming from climate perturbations, thus we may produce hardier and more resilient crops."

Modern vaccines such as those against Sars-CoV-2 use tiny lipid spheres to transport genetic information into cells and let the body build up an immune defense against the virus. A team of scientists from Erlangen, Dresden, and London has now developed a completely new method to very efficiently deliver not only genes but also drugs and other substances into cells. The researchers from the Max-Planck-Zentrum für Physik und Medizin (MPZPM) in Erlangen, the Technical University of Dresden, and The Institute of Cancer Research in London have named the method Progressive Mechanoporation and have now published it in the scientific journal "Lab on a Chip". They have also filed a patent.

Ruchi Goswami and Alena Uvizl were part of a team of scientists led by Salvatore Girardo (Erlangen) and Jörg Mansfeld (Dresden/London) who have developed the Progressive Mechanoporation. They have built a special polymer biochip that contains a series of microchannels. Each microchannel is narrower than the previous one, finally reaching a size more than ten times thinner than a human hair. The scientists pass the cells through these channels, causing the cells to stretch more and more. The stretching creates pores in their cell membrane, allowing molecules to pass through these pores and get inside the cells. Once the cells have passed through the channels, the pores close again. The scientists demonstrated that Progressive Mechanoporation can deliver even very large proteins inside the cells. As a proof of concept the scientists used antibodies and CRISPR/Cas9, the genetic scissors whose discovery led to a last year's Nobel Prize.

Potentially a new routine procedure for hospitals

"The big advantage of our method is that we can pass up to 10,000 cells per second through the chip," explains Salvatore Girardo, leader of the technology development and service group Lab-on-a-Chip at the MPZPM. At the same time, the method is very gentle. Compared to other techniques, very few cells get damaged.

The Progressive Mechanoporation method could be used in drug development and allow pharmaceutical companies to efficiently test new molecule candidates. In addition, the process can be easily automated. Jörg Mansfeld, a research group leader at the Biotechnology Center (BIOTEC) of TU Dresden and at The Institute of Cancer Research, London, adds: "I can envision that in the future, hospitals will be able to routinely examine and even treat patients' cells using Progressive Mechanoporation."

CHICAGO --- A new Northwestern Medicine study of placentas from patients who received the COVID-19 vaccine during pregnancy found no evidence of injury, adding to the growing literature that COVID-19 vaccines are safe in pregnancy.

"The placenta is like the black box in an airplane. If something goes wrong with a pregnancy, we usually see changes in the placenta that can help us figure out what happened," said corresponding author Dr. Jeffery Goldstein, assistant professor of pathology at Northwestern University Feinberg School of Medicine and a Northwestern Medicine pathologist. "From what we can tell, the COVID vaccine does not damage the placenta."

The study will be published May 11 in the journal Obstetrics & Gynecology. To the authors' knowledge, it is the first study to examine the impact of the COVID vaccines on the placenta.

"We have reached a stage in vaccine distribution where we are seeing vaccine hesitancy, and this hesitancy is pronounced for pregnant people," said study co-author Dr. Emily Miller, Northwestern Medicine maternal fetal medicine physician and assistant professor of obstetrics and gynecology at Feinberg. "Our team hopes these data, albeit preliminary, can reduce concerns about the risk of the vaccine to the pregnancy."

The study authors collected placentas from 84 vaccinated patients and 116 unvaccinated patients who delivered at Prentice Women's Hospital in Chicago and pathologically examined the placentas whole and microscopically following birth. Most patients received vaccines - either Moderna or Pfizer - during their third trimester.

Last May, Goldstein, Miller and collaborators from Northwestern and Ann & Robert H. Lurie Children's Hospital of Chicago published a study that found placentas of women who tested positive for the COVID-19 virus while pregnant showed evidence of injury (abnormal blood flow between mother and baby in utero). Pregnant patients who want to get vaccinated to avoid contracting the disease should feel safe doing so, Miller said.

"We are beginning to move to a framework of protecting fetuses through vaccination, rather than from vaccination," Miller said.

In April, the scientists published a study showing pregnant women make COVID antibodies after vaccination and successfully transfer them to their fetuses.

"Until infants can get vaccinated, the only way for them to get COVID antibodies is from their mother," Goldstein said.

The placenta's role in the immune system

The placenta is the first organ that forms during pregnancy. It performs duties for most of the fetus' organs while they're still forming, such as providing oxygen while the lungs develop and nutrition while the gut is forming.

Additionally, the placenta manages hormones and the immune system, and tells the mother's body to welcome and nurture the fetus rather than reject it as a foreign intruder.

"The Internet has amplified a concern that the vaccine might trigger an immunological response that causes the mother to reject the fetus," Goldstein said. "But these findings lead us to believe that doesn't happen."

The scientists also looked for abnormal blood flow between the mother and fetus and problems with fetal blood flow - both of which have been reported in pregnant patients who have tested positive for COVID.

The rate of these injuries was the same in the vaccinated patients as for control patients, Goldstein said. The scientists also examined the placentas for chronic histiocytic intervillositis, a complication that can happen if the placenta is infected, in this case, by SARS-CoV-2. Although this study did not find any cases in vaccinated patients, it's a very rare condition that requires a larger sample size (1,000 patients) to differentiate between vaccinated and unvaccinated patients.

One of the most prominent evils of rapid industrialization has been the emission of toxic pollutants into the surrounding biosphere, with often disastrous consequences for human beings. Several industrial processes, such as chemical manufacturing and printing, along with facilities such as power plants emit volatile organic compounds (VOCs) that are known to be cancer-causing and raise an important environmental issue in need of a solution. Traditionally, VOCs are controlled via a process called "catalytic oxidation," in which they are converted into benign materials in the presence of noble metal (e.g. gold, silver, and platinum) nanoparticles. However, the process is expensive and requires a fine-tuning of nanoparticle characteristics. Thus, a catalytic process not requiring noble metal catalysts is highly desirable. While transition metals and their oxides are a possible alternative, they require complex syntheses and precise chemical composition control.

So, can we do better than this? Turns out, we can! A team of scientists led by Prof. Takashi Shirai from Nagoya Institute of Technology (NITech), Japan, reported a complete catalytic decomposition of VOC using an inorganic compound called "hydroxyapatite" (HAp), a naturally occurring form of the mineral calcium phosphate that makes up most of the human bone structure. "HAp is made of elements abundant in nature, is non-toxic and exhibits high biocompatibility. Our results, thus, opened up a new possibility for designing cheap, noble-metal-free catalysts for VOC control," says Prof. Shirai.

In a new study published in Scientific Reports, Prof. Shirai and his colleague Yunzi Xin from NITech now take things further by tailoring the "active surface" of HAp using a mechanochemical treatment under ambient conditions that leads to a highly efficient catalytic oxidation of VOC with 100% conversion to harmless compounds! Specifically, they mixed initial HAp with ceramic balls in a vessel and conducted "planetary ball milling" at room temperature and ambient pressure. This essentially altered the chemical structure of HAp and allowed for its selective tailoring by simply changing the ball size.

By using different ball sizes (3, 10, and 15 mm) to systematically vary the morphology, crystallinity, surface defects/oxygen vacancy, acidity/basicity, and VOC affinity of HAps, the scientists carried out their characterization using various techniques such as scanning electron microscopy, powder X-ray diffraction, Fourier transform infrared spectrometry, X-ray photoelectron spectroscopy, electron spin resonance analysis, surface acidity/basicity evaluation, and gas-flowing diffuse reflectance infrared Fourier transform spectroscopy.

They observed a predominance of oxygen vacancy formation in the PO43- (triply charged PO4) site along with an enhanced basic site population caused by a selective mechanochemical activation of the c-plane (plane perpendicular to the symmetry axis) of the hexagonal HAp crystal and attributed it to the excellent catalytic conversion of VOC to CO2/CO.

Moreover, they found that HAps treated with 3 mm balls showed superior catalytic activity over that treated with 10- and 15-mm balls, even though larger balls caused more defects and basicity. By looking at the surface absorption of a VOC, ethyl acetate, scientists attributed this anomaly to the inhibited absorption of ethyl acetate in HAp treated with larger balls, leading to suppressed catalysis.

The results have excited scientists about the future prospects of HAps. "We expect that our catalyst will contribute significantly to VOC controlling and environmental cleaning all over the world by next decade, achieving the sustainable goals of clean air and water, affordable energy, and climate action," comments Prof. Shirai, excited.

Indeed, this is one huge step towards a more eco-friendly society!

Australian photovoltaics researchers have made a 'cool' discovery: Singlet fission and tandem solar cells - two innovative ways to generate solar power more efficiently - also help to lower operating temperatures and keep devices running for longer.

Tandem cells can be made from a combination of silicon - the most commonly used photovoltaics material - and new compounds like perovskite nanocrystals, which can have a larger bandgap than silicon and help the device to capture more of the solar spectrum for energy generation.

Singlet fission, meanwhile, is a technique that produces twice the electronic charge carriers than normal for each photon of light that's absorbed. Tetracene is used in these devices to transfer the energy generated by singlet fission into silicon.

Scientists and engineers around the world are working on the best way to incorporate tandem cells and singlet fission processes into commercially viable devices that can take over from conventional, single junction silicon solar cells commonly found on rooftops and in large-scale arrays.

Now, work conducted by the School of Photovoltaic and Renewable Energy Engineering and the ARC Centre of Excellence in Exciton Science, both based at UNSW in Sydney, has highlighted some key advantages to both tandem cells and singlet fission.

The researchers showed that both silicon/perovskite tandem cells and tetracene-based singlet fission cells will run at lower temperatures than conventional silicon devices. This will reduce the impact of damage from heat on the devices, extending their lifespan and lowering the cost of the energy they produce.

For example, a 5-10°C reduction in module operating temperature corresponds to a 2%-4% gain in annual energy production. And the lifetime of devices is generally found to double for every 10°C reduction in temperature. That means an increase in lifetime of 3.1?years for the tandem cells and 4.5?years for singlet fission cells.

In the case of singlet fission cells, there's another handy benefit. When tetracene inevitably degrades, it becomes transparent to solar radiation, allowing the cell to continue functioning as a conventional silicon device, albeit one that has initially operated at a lower temperature and delivered superior efficiency during the first phase of its lifecycle.

Lead author Dr Jessica Yajie Jiang said: "The commercial value of photovoltaic technologies can be increased by either increasing the energy conversion efficiency or the operational lifespan. The former is the primary driver for the development of next generation technologies, while little thought has been given to the potential lifespan advantages.

"We demonstrated that these advanced photovoltaic technologies also show ancillary benefits in terms of enhanced lifespan by operating at lower temperature and more resilience under degradation, introducing a new paradigm to evaluate the potential of new solar energy technologies."

ORLANDO, May 10, 2021 -University of Central Florida researchers are building on their technology that could pave the way for hypersonic flight, such as travel from New York to Los Angeles in under 30 minutes.

In their latest research published in the journal Proceedings of the National Academy of Sciences, the researchers discovered a way to stabilize the detonation needed for hypersonic propulsion by creating a special hypersonic reaction chamber for jet engines.

"There is an intensifying international effort to develop robust propulsion systems for hypersonic and supersonic flight that would allow flight through our atmosphere at very high speeds and also allow efficient entry and exit from planetary atmospheres," says study co-author Kareem Ahmed, an associate professor in UCF's Department of Mechanical and Aerospace Engineering. "The discovery of stabilizing a detonation -- the most powerful form of intense reaction and energy release -- has the potential to revolutionize hypersonic propulsion and energy systems."

The system could allow for air travel at speeds of Mach 6 to 17, which is more than 4,600 to 13,000 miles per hour. The technology harnesses the power of an oblique detonation wave, which they formed by using an angled ramp inside the reaction chamber to create a detonation-inducing shock wave for propulsion.

Unlike rotating detonation waves that spin, oblique detonation waves are stationary and stabilized.

The technology improves jet propulsion engine efficiency so that more power is generated while using less fuel than traditional propulsion engines, thus lightening the fuel load and reducing costs and emissions.

In addition to faster air travel, the technology could also be used in rockets for space missions to make them lighter by requiring less fuel, travel farther and burn more cleanly.

Detonation propulsion systems have been studied for more than half a century but had not been successful due to the chemical propellants used or the ways they were mixed. Previous work by Ahmed's group overcame this problem by carefully balancing the rate of the propellants hydrogen and oxygen released into the engine to create the first experimental evidence of a rotating detonation.

However, the short duration of the detonation, often occurring for only micro or milliseconds, makes them difficult to study and impractical for use.

In the new study, however, the UCF researchers were able to sustain the duration of a detonation wave for three seconds by creating a new hypersonic reaction chamber, known as a hypersonic high-enthalpy reaction, or HyperREACT, facility. The facility contains a chamber with a 30-degree angle ramp near the propellent mixing chamber that stabilizes the oblique detonation wave.

"This is the first time a detonation has been shown to be stabilized experimentally," Ahmed says. "We are finally able to hold the detonation in space in oblique detonation form. It's almost like freezing an intense explosion in physical space."

Gabriel Goodwin, an aerospace engineer with the Naval Research Laboratory's Naval Center for Space Technology and study co-author, says their research is helping to answer many of the fundamental questions that surround oblique detonation wave engines.

Goodwin's role in the study was to use the Naval Research Laboratory's computational fluid dynamics codes to simulate the experiments performed by Ahmed's group.

"Studies such as this one are crucial to advancing our understanding of these complex phenomena and bringing us closer to developing engineering-scale systems," Goodwin says.

"This work is exciting and pushing the boundaries of both simulation and experiment," Goodwin says. "I'm honored to be a part of it."

The study's lead author is Daniel Rosato '19 '20MS, a graduate research assistant and a recipient of UCF's Presidential Doctoral Fellowship.

Rosato has been working on the project since he was an aerospace engineering undergraduate student and is responsible for experiment design, fabrication, and operation, as well as data analysis, with assistance from Mason Thorton, a study co-author and an undergraduate research assistant.

Rosato says the next steps for the research are the addition of new diagnostics and measurement tools to gain a deeper understanding of the phenomena they are studying.

"After that, we will continue exploring more experimental configurations to determine in more detail the criteria with which an oblique detonation wave can be stabilized," Rosato says.

If successful in advancing this technology, detonation-based hypersonic propulsion could be implemented into human atmospheric and space travel in the coming decades, the researchers say.