Culture

Engineers have taken their inspiration from shells and grapefruits to create what they say is the first manufactured non-cuttable material.

This new material, which could be used in the security and health and safety industries, can turn back the force of a cutting tool upon itself.

The lightweight material - named Proteus after the shape-changing mythical god - is made of ceramic spheres encased in a cellular aluminium structure that in tests could not be cut by angle grinders, drills or high-pressure water jets.

An international research team, led by Durham University, UK, and Fraunhofer Institute for Machine Tools and Forming Technology IWU in Chemnitz in Germany, got the idea for the new material from the tough cellular skin of the grapefruit and the fracture resistant shells of molluscs.

Abalone sea creatures are built from tiles interlinked with a biopolymer material that make them resistant to fractures.
To resist the most violent forcible entry tools, organic materials such as aragonite tiles - found in mollusc shells - were replaced in the new material with industrial, alumina ceramics and an aluminium, metallic foam matrix.

The new material is strong, light and non-cuttable. The researchers say, it could be used to make bike locks, lightweight armour and in protective equipment for people who work with cutting tools.

The findings are published in the journal Scientific Reports.
The new material system is dynamic with an evolving internal structure that creates high-speed motion where it interacts with the cutting tools. The dynamic response is more akin to living structures.

The material is made from a cellular aluminium structure wrapped around ceramic spheres and this has a doubly destructive effect on cutting tools.
When cut with an angle grinder or drill, the vibrations created by the ceramic spheres inside the casing blunt the cutting disc or drill bit.

The interaction between the disc and ceramic sphere creates an interlocking, vibrational connection that resists the cutting tool indefinitely.

The blade is gradually eroded, and eventually rendered ineffective as the force and energy of the disc or the drill is turned back on itself, and it is weakened and destroyed by its own attack.

In addition, the ceramics fragment into fine particles, which fill the cellular structure of the material and harden as the speed of the cutting tool is increased due to interatomic forces between the ceramic grains. In this way the adaptive nature of the material further repulses any attack.

Water jets were also found to be ineffective because the curved surfaces of the ceramic spheres widen the jet, which substantially reduces its speed and weakens its cutting capacity.

Lead author Dr Stefan Szyniszewski, Assistant Professor of Applied Mechanics, in the Department of Engineering, Durham University, said: "We were intrigued by how the cellular structure of the grapefruit and the tiled structure of mollusc shells can prevent damage to the fruit or the creatures inside, despite being made of relatively weak organic building blocks.

"These natural structures informed the working principle of our metallic-ceramic material, which is based on dynamic interaction with the applied load, in contrast to passive resistance.

"Essentially cutting our material is like cutting through a jelly filled with nuggets. If you get through the jelly you hit the nuggets and the material will vibrate in such a way that it destroys the cutting disc or drill bit.

"The ceramics embedded in this flexible material are also made of very fine particles which stiffen and resist the angle grinder or drill when you're cutting at speed in the same way that a sandbag would resist and stop a bullet at high speed.

"This material could have lots of useful and exciting applications in the security and safety industries. In fact, we are not aware of any other manufactured non-cuttable material in existence as of now."

Study co-author Dr Miranda Anderson, Department of Philosophy, University of Stirling said: "Because the successful resistance of our material system requires it to undergo internal transformations, we chose the name Proteus.

"In 1605, Francis Bacon compared natural materials to Proteus who 'ever changed shapes' and he argued that through experimentation we can reveal the metamorphic qualities of materials."

Dr Szyniszewski added: "This is what we've achieved with this new material and we're excited by its potential."

The researchers have a patent pending for their material technology and they hope to work with industry partners so it can be developed into products for the marketplace.

Could we create massive sulfuric acid clouds that limit global warming and help meet the 2015 Paris international climate goals, while reducing unintended impacts?

Yes, in theory, according to a Rutgers co-authored study in the journal Earth System Dynamics. Spraying sulfur dioxide into the upper atmosphere at different locations, to form sulfuric acid clouds that block some solar radiation, could be adjusted every year to keep global warming at levels set in the Paris goals. Such technology is known as geoengineering or climate intervention.

But the regional impacts of geoengineering, including on precipitation and the Antarctic ozone layer hole, depend on how much greenhouse gas emissions from humanity are being reduced simultaneously. If carbon dioxide emissions from burning coal, oil and natural gas continue unabated, geoengineering would not prevent large decreases in precipitation and depletion of the life-sustaining ozone layer. If society launches massive efforts to reduce carbon emissions, remove carbon dioxide from the atmosphere and adapt to climate change, small doses of geoengineering may help reduce the most dangerous aspects of global warming, the study says.

"Our research shows that no single technology to combat climate change will fully address the growing crisis, and we need to stop burning fossil fuels and aggressively harness wind and solar energy to power society ASAP," said co-author Alan Robock, a Distinguished Professor in the Department of Environmental Sciences in the School of Environmental and Biological Sciences at Rutgers University-New Brunswick. "This mitigation is needed whether society ever decides to deploy geoengineering or not."

Using a climate model, scientists studied whether it's possible to create sulfuric acid clouds in the stratosphere to reflect solar radiation and limit global warming to 1.5 degrees Celsius (2.7 degrees Fahrenheit) or 2 degrees Celsius (3.6 degrees Fahrenheit) above preindustrial temperatures. Those two goals were set at the 2015 United Nations climate change conference in Paris to try to reduce the negative impacts of global warming.

Robock noted that the study was done with only one climate model that addressed different global warming and geoengineering scenarios. Other studies are needed to check the robustness of the results and to further examine the potential risks of any geoengineering scheme.

NEW HAMPTON, N.Y., July 20, 2020 -- On Wednesday, July 15, 2020, the Dietary Guidelines Advisory Committee (DGAC or Committee) - a group comprised of 20 nationally recognized health and nutrition experts - published the Scientific Report of the 2020 Dietary Guidelines Advisory Committee: Advisory Report to the Secretary of Agriculture and the Secretary of Health and Human Services. Among its findings, the Committee concluded that current choline intake levels are too low for most Americans and found low intake levels among infants and toddlers, as well as vulnerable populations like pregnant and lactating women, especially concerning.

"The Committee's scientific report shines a light on the growing body of evidence that shows choline plays a critical role in health during specific life stages," says Marie Caudill, PhD, RD, Professor, Cornell University and an internationally recognized choline researcher. "Unfortunately, consumption data tell us choline is widely under-consumed, and it's concerning that those populations who would benefit most from choline, such as pregnant and lactating women and infants and children, fall short of meeting intake targets. In fact, only 8 percent of pregnant women are meeting choline recommendations."

Choline is an essential nutrient that supports a variety of processes at all stages of life and throughout the body, including fetal and infant development; cognition and memory; energy and fitness; metabolism; and liver health. While more research is needed for choline to reach the level of a 'nutrient of public health concern,' the Committee recognized choline as a 'nutrient that poses public health challenges' for all infants and toddlers between ages 12 and 24 months; and special attention around choline inadequacies was specifically noted for girls and boys ages 9 to 14; and the vulnerable pregnant population and women who are lactating. Choline is naturally found in some foods; yet, based on typical and recommended eating patterns, it is difficult to meet daily choline needs through foods alone. In fact, the DGAC presented three food pattern styles, which generally meet all nutrient needs across the lifespan, except for a few such as choline. Importantly, the Committee noted that many supplements do not yet contain sufficient amounts of choline, indicating an important opportunity for both supplement innovations, as well as food fortification, in the future.

"The Committee's report clearly highlights the challenges of meeting choline intake targets through food alone," added Caudill. "Americans need guidance on how to choose supplements to help fill nutrient gaps, particularly for pregnant women as most recognized prenatal vitamins don't contain enough--if any--choline."

"Choline's increased recognition in the DGAC report is an important scientific milestone for the public health community," says Jonathan Bortz, MD, Senior Director, Nutrition Science, Balchem. "We are quickly approaching an inflection point in time for choline awareness. In addition to the findings released in this report, Balchem has, and will continue to support research needed to develop a blood biomarker for choline, which will provide a more accurate understanding of the level of deficiency among Americans and help to generate stronger guidance and messages."

Choline can be purchased online or in specialty stores as a stand-alone, over-the-counter supplement; incorporated into some prenatal vitamins or packaged along with prenatal vitamins; and fortified in branded milk products, specifically:

- Bayer recently launched a "One A Day Women's Prenatal Advanced Complete Multivitamin with Brain Support," that includes a side-by-side prenatal multivitamin plus a supplement that provides 110mg of choline, helping to substantially close the gap in pregnant women's daily needs.

- Danone's Horizon Organic brand developed milk for young children--Growing Years--that is fortified to contain 55mg of choline per serving, providing between 10 percent to 27 percent of children's daily needs, depending on age and gender.

"The Committee's report has provided critical research directions to help inform Balchem's long-standing commitment to choline research and science communications," added Bortz. "We look forward to continuing to support science and product innovation to ensure all Americans throughout the lifespan can benefit from increased choline, as part of healthy diets."

About a quarter of people with drug or alcohol use disorders also suffer from post-traumatic stress disorder (PTSD), which is typically caused by a traumatic or stressful life event such as rape or combat, and which leaves the person with intense anxiety. However, patients and health care providers have been reluctant to pursue the gold-standard treatment for PTSD -- cognitive behavioral therapy -- because they anticipate that thinking and talking about traumatic events during therapy will cause relapse.

Johns Hopkins researchers have now demonstrated that behavior therapy that exposes people to memories of their trauma doesn't cause relapses of opioid or other drug use, and that PTSD severity and emotional problems have decreased after the first therapy session.

These findings were published June 29 in the Journal of Traumatic Stress.

This work originated from a larger project in which Jessica Peirce, Ph.D., associate professor of psychiatry and behavioral sciences at the Johns Hopkins University School of Medicine, and her colleagues tested how to get often reluctant patients in addiction treatment to participate in PTSD therapy. In a 2017 article in the Journal of Consulting and Clinical Psychology, her team showed that patients with opioid dependence attended on average nine exposure therapy sessions for treating PTSD when given money as an incentive, compared with only one session without the incentive.

Building on this earlier work, for the new study, her team examined week-to-week comparisons of cravings for opioids or other drugs before and after therapy sessions, self-reported days of drug use, and other distress. The researchers found there was no increase in use of opioids or other drugs, or in reported instances of stress after therapy sessions to treat PTSD. By the ninth therapy session, PTSD severity scores decreased, on average, by 54% compared to the first session.

"Now that we have evidence that treating PTSD won't impact recovery, patients can request therapy, and mental health providers have a duty to make it available to their patients," says Peirce. "There is a lot more resilience within this population than many health care providers give them credit for, and not offering the proper treatment is doing patients a disservice."

Alzheimer's disease is a progressive disorder in which the nerve cells (neurons) in a person's brain and the connections among them degenerate slowly, causing severe memory loss, intellectual deficiencies, and deterioration in motor skills and communication. One of the main causes of Alzheimer's is the accumulation of a protein called amyloid β (Aβ) in clusters around neurons in the brain, which hampers their activity and triggers their degeneration. Studies in animal models have found that increasing the aggregation of Aβ in the hippocampus--the brain's main learning and memory center--causes a decline in the signal transmission potential of the neurons therein. This degeneration affects a specific trait of the neurons, called "synaptic plasticity," which is the ability of synapses (the site of signal exchange between neurons) to adapt to an increase or decrease in signaling activity over time. Synaptic plasticity is crucial to the development of learning and cognitive functions in the hippocampus. Thus, Aβ and its role in causing cognitive memory and deficits have been the focus of most research aimed at finding treatments for Alzheimer's.

Now, advancing this research effort, a team of scientists from Japan, led by Professor Akiyoshi Saitoh from the Tokyo University of Science, has looked at oxytocin, a hormone conventionally known for its role in the female reproductive system and in inducing the feelings of love and well-being. "Oxytocin was recently found to be involved in regulating learning and memory performance, but so far, no previous study deals with the effect of oxytocin on Aβ-induced cognitive impairment," Prof Saitoh says. Realizing this, Prof Saitoh's group set out to connect the dots. Their findings are published in Biochemical and Biophysical Research Communication.

Prof Saitoh and team first perfused slices of the mouse hippocampus with Aβ to confirm that Aβ causes the signaling abilities of neurons in the slices to decline or--in other words--impairs their synaptic plasticity. Upon additional perfusion with oxytocin, however, the signaling abilities increased, suggesting that oxytocin can reverse the impairment of synaptic plasticity that Aβ causes.

To find out how oxytocin achieves this, they conducted a further series of experiments. In a normal brain, oxytocin acts by binding with special structures in the membranes of brain cells, called oxytocin receptors. The scientists artificially "blocked" these receptors in the mouse hippocampus slices to see if oxytocin could reverse Aβ-induced impairment of synaptic plasticity without binding to these receptors. Expectedly, when the receptors were blocked, oxytocin could not reverse the effect of Aβ, which shows that these receptors are essential for oxytocin to act.

Oxytocin is known to facilitate certain cellular chemical activities that are important in strengthening neuronal signaling potential and formation of memories, such as influx of calcium ions. Previous studies have suspected that Aβ suppresses some of these chemical activities. When the scientists artificially blocked these chemical activities, they found that addition of oxytocin addition to the hippocampal slices did not reverse the damage to synaptic plasticity caused by Aβ. Additionally, they found that oxytocin itself does not have any effect on synaptic plasticity in the hippocampus, but it is somehow able to reverse the ill-effects of Aβ.

Prof Saitoh remarks, "This is the first study in the world that has shown that oxytocin can reverse Aβ-induced impairments in the mouse hippocampus." This is only a first step and further research remains to be conducted in vivo in animal models and then humans before sufficient knowledge can be gathered to reposition oxytocin into a drug for Alzheimer's. But, Prof Saitoh remains hopeful. He concludes, "At present, there are no sufficiently satisfactory drugs to treat dementia, and new therapies with novel mechanisms of action are desired. Our study puts forth the interesting possibility that oxytocin could be a novel therapeutic modality for the treatment of memory loss associated with cognitive disorders such as Alzheimer's disease. We expect that our findings will open up a new pathway to the creation of new drugs for the treatment of dementia caused by Alzheimer's disease."

In hotter, dryer conditions with climate change, a secret agent for more sustainable agricultural production could lie in harvesting the diverse beneficial soil microbiome in native bushland settings, scientists say.

New research from CSIRO, Flinders University and La Trobe University highlights the importance of soil biological health and further potential to use organic rather than chemical farm inputs for crop production.

"We know antibiotics are very useful in pharmaceuticals, and actinobacteria found plentifully and in balance in various natural environments play a vital role in the plant world," says lead author Dr Ricardo Araujo, a visiting Flinders University researcher from the University of Porto in Portugal.

"These actinobacterial communities contribute to global carbon cycling by helping to decompose soil nutrients, increase plant productivity, regulate climate support ecosystems - and are found in abundance in warm, dry soil conditions common in Australia."

A new article in Soil Biology and Biochemistry is one of the first dedicated studies of Australian actino-bacterial diversity in different areas of the Southern Hemisphere - using the bacterial gene sequence dataset generated through the 'Biomes of Australian Soil Environments' project with soil samples from across the nation, including mainland, the island state of Tasmania as well as King Island, Christmas Island and the Northern Antarctica for comparative soil profiles.

Other researchers from the La Trobe University AgriBio Centre contributed to the analysis of 2211 actinobacterial operational taxonomic units (OTUs) mapped in mainland Australia, and 490 OTUs from Tasmania, King Island, Christmas Island and Northern Antarctica.

CSIRO Agriculture and Food senior principal research scientist, Associate Professor Gupta Vadakattu, says the dfferences we found between mainland Australia and more remote locations showed how agriculture has had an impact on the diversity of actinobacterial.

"Our study shows how native vegetation is a reservoir for these important soil microorganisms, and this could be used to enrich adjoining agricultural soils," says Associate Professor Vadakattu, adding an intriguing finding was the similarity in actinobacteria profiles of King Island and areas of Antarctica where these continents were once connected.

"Patterns of actinobacteria dispersal suggest only a small fraction of them had the capability of spreading throughout the Southern Hemisphere, especially across oceans."

Flinders University colleague Professor Chris Franco, says biotechnology has long benefited from actinobacteria for human and animal health products, and increasingly in sustainable agriculture.

"The diversity and structure of soil antinobacterial communities are influenced by multiple factors, representing one of the most abundant soil bacterial taxa across a diverse range of ecological regions - from deserts to Antarctica," Professor Franco says.

"There is much more we need to learn about their potential in primary production and retaining and incorporating native plants in our ecosystems."

Various scientific studies have warned of a global decline in the abundance and diversity of insects. These studies have been carried out mainly on the European and North American continents, with other regions, such as islands, have been less studied.

This in mind, an international research team from Portugal, France and Finland studied the insects captured over six years in the native forests of Terceira island, the Azores.

The results revealed that the diversity of exotic species of arthropods increased with time. Exotic species have been introduced into the archipelago consciously or inadvertently through economic activities.

"A greater diversity of exotic species may imply a change in various types of ecosystem services, disrupting processes such as predation and recycling of nutrients," says Paulo Borges, researcher at the at the University of the Azores, Portugal.

In the Azores, exotic species have their maximum abundance and diversity in habitats created by man.

"The fragmentation of native habitats and the proximity of some of these non-native habitats is promoting a flow of exotic species to the native forest. The process seems to be increasing in recent years possibly due to the combination of climate change and degradation of the native forest due to the spread of invasive plants,"explains Pedro Cardoso, curator at the Finnish Museum of Natural History Luomus, University of Helsinki, Finland.

The study also shows a slight decrease in the abundance of island species that are not found anywhere else on the planet, such as the Azorean money spider (Savigniorrhipis acoreensis), which occurs on all the archipelago with the exception of Corvo island.

The study took place between 2013 and 2018. During that time, 30 thousand arthropods were captured in the native forest of Terceira. The insects collected corresponded to 159 species, 32 of which are endemic.

A new guideline aimed at helping clinicians identify the difficult-to-diagnose acute aortic syndrome is published in CMAJ (Canadian Medical Association Journal).

Acute aortic syndrome (AAS) is a life-threatening condition that underlies 1 in 2000 visits to the emergency department for severe chest or back pain. The rate of misdiagnosis is estimated to be as high as 38%, and the risk of death can increase 2% for every hour of delay in diagnosis.

The target audience for the guideline includes emergency physicians, primary care clinicians, internists, radiologists, vascular surgeons, cardiothoracic surgeons and critical care physicians as well as decision-makers and patients.

"This guideline is intended as a resource for practising clinicians, both as an evidence base and a guide to investigation for this high-risk aortic catastrophe," writes Dr. Robert Ohle, an emergency physician at the Health Science North Research Institute, Northern Ontario School of Medicine, Sudbury, Ontario, with coauthors.

Recommendations include:

* Assessment of risk factors, pain features and high-risk physical exam findings to establish pre-test disease risk

o Risk factors include connective tissue disease, aortic valve disease, recent aortic procedure, aortic aneurysm and family history of AAS

o High-risk pain includes sudden-onset or thunderclap pain, severe or worst-ever pain, tearing, migrating or radiating pain

o High-risk physical exam findings include aortic regurgitation, pulse deficit, neurological deficit and hypotension/pericardial effusion

* Diagnostic strategy

o The guideline recommends no investigation of those at low risk, D-dimer testing of people of moderate risk and immediate electrocardiogram-gated computed tomography (CT) of the aorta for high-risk individuals

To help with decision-making, the guideline group created a clinical decision aid to accompany the guideline.

The guideline can be adapted by clinicians based on local circumstances, as a one-size-fits-all approach may not be feasible.

"This document may serve as a basis for adaption by local, regional or national guideline groups," write the authors. "For example, guideline implementation in an urban centre with 24-hour access to CT may differ from a rural or remote location that requires transfer of a patient with accompanying staff."

A school-based vision screening program in kindergarten, shown to be effective at identifying untreated vision problems in 1 in 10 students, could be useful to implement widely in diverse communities, according to new research in CMAJ (Canadian Medical Association Journal).

Vision problems can lead to amblyopia (known as "lazy eye") and potential learning problems.

"These are practical details needed by funders to make decisions about implementing school-based vision screening," writes Dr. Mayu Nishimura, Department of Psychology, Neuroscience & Behaviour, McMaster University, Hamilton, and Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children (SickKids), Toronto, with coauthors.

Researchers offered vision screening to 5884 children in junior and senior kindergarten at 43 schools in 15 Ontario communities from October 2015 to June 2017. Most children participated, and just under half of participants were referred for follow-up eye exams. More than 10% of children (516) who were screened were found to have a visual problem during the follow-up eye exam. For 67% of the children found to have a visual problem, this was their first eye exam. Amblyopia was found in 164 children (3.4%), and 458 (9.5%) children were prescribed glasses.

"These numbers show that the status quo (in 2015-2017) was insufficient in identifying and treating young children with a visual problem before grade 1. The willingness of school boards and principals to participate in our study underlines the recognized need for better access to visual health care for children in kindergarten," write the authors.

Adequate follow-up care, such as visits to eye care professionals, prescriptions for glasses, appointment reminders and information about the importance of treatment, are critical to ensure the success of a vision screening program.

"Feasibility of a school-based vision screening program to detect undiagnosed visual problems in kindergarten children in Ontario" is published July 20, 2020.

The “enhanced paper grip test” validated by researchers from the Centre for Biomechanics and Rehabilitation Technologies (CBRT) at Staffordshire University involves pulling a small card from underneath the participant’s foot while asking them to grip with their big toe (Hallux).

The proposed test can potentially be used to monitor muscle weakness in clinics for better falls-risk assessment in patients with diabetes.

Dr Aoife Healy, Associate Professor of Human Movement Biomechanics at CBRT, said: “The paper grip test is a simple, clinically applicable test to detect muscle weakness in the foot. The current paper builds on our previous work and shows its usefulness in assessing strength and balance in this group of vulnerable patients.”

The experiment involved assessing twenty healthy volunteers at Staffordshire University’s specialist Biomechanics labs and ten people with diabetes at a diabetic foot clinic in India.

Hallux grip force was previously found to be strongly linked to the strength of all muscle groups of the foot and ankle and to the ability to maintain balance. The latest results published in Gait and Posture on a modified test shows the reliability and validity of Hallux grip force during clinical assessment.

Dr Lakshmi Sundar, a co-author in this study and a diabetic foot specialist from Chennai in India, added: “This type of simple clinical assessment is extremely valuable in low resource settings and helps in providing effective clinical advice.”

Dr Panagiotis Chatzistergos, Associate Professor in Orthopaedic and Rehabilitation Biomechanics, who led this study highlighted: “The original version of the paper grip test was shown to be effective in detecting foot muscle-weakening but its outcome is operator-dependent. To overcome this limitation, we have developed this enhanced test that replaces the pass/fail outcome with a continuous measurement of the pulling force that is needed to remove the card.”

This latest study is part of the Centre for Biomechanics and Rehabilitation Technologies’ wider work in the area of diabetic foot management which includes research to help prevent life-threatening foot ulcers and amputations.

Professor Nachi Chockalingam, Director of the Centre for Biomechanics and Rehabilitation Technologies, said: “Falls and fear of falling are a major issue in the management of older adults. Also, falling for the first time sets in motion a cycle of increased fear of falling, reduced activity and loss of strength. This leads to a higher risk for further falls. So, it is important to identify individuals who might fall and preventing the first fall is extremely important.”

Read the full paper, published in Gait and Posture, here - Reliability and validity of an enhanced paper grip test; a simple clinical test for assessing lower limb strength

Journal

Gait & Posture

DOI

10.1016/j.gaitpost.2020.07.011

PITTSBURGH--A robot travelling from point A to point B is more efficient if it understands that point A is the living room couch and point B is a refrigerator, even if it's in an unfamiliar place. That's the common sense idea behind a "semantic" navigation system developed by Carnegie Mellon University and Facebook AI Research (FAIR).

That navigation system, called SemExp, last month won the Habitat ObjectNav Challenge during the virtual Computer Vision and Pattern Recognition conference, edging a team from Samsung Research China. It was the second consecutive first-place finish for the CMU team in the annual challenge.

SemExp, or Goal-Oriented Semantic Exploration, uses machine learning to train a robot to recognize objects -- knowing the difference between a kitchen table and an end table, for instance -- and to understand where in a home such objects are likely to be found. This enables the system to think strategically about how to search for something, said Devendra S. Chaplot, a Ph.D. student in CMU's Machine Learning Department.

"Common sense says that if you're looking for a refrigerator, you'd better go to the kitchen," Chaplot said. Classical robotic navigation systems, by contrast, explore a space by building a map showing obstacles. The robot eventually gets to where it needs to go, but the route can be circuitous.

Previous attempts to use machine learning to train semantic navigation systems have been hampered because they tend to memorize objects and their locations in specific environments. Not only are these environments complex, but the system often has difficulty generalizing what it has learned to different environments.

Chaplot -- working with FAIR's Dhiraj Gandhi, along with Abhinav Gupta, associate professor in the Robotics Institute, and Ruslan Salakhutdinov, professor in the Machine Learning Department -- sidestepped that problem by making SemExp a modular system.

The system uses its semantic insights to determine the best places to look for a specific object, Chaplot said. "Once you decide where to go, you can just use classical planning to get you there."

This modular approach turns out to be efficient in several ways. The learning process can concentrate on relationships between objects and room layouts, rather than also learning route planning. The semantic reasoning determines the most efficient search strategy. Finally, classical navigation planning gets the robot where it needs to go as quickly as possible.

Semantic navigation ultimately will make it easier for people to interact with robots, enabling them to simply tell the robot to fetch an item in a particular place, or give it directions such as "go to the second door on the left."

Asian gypsy moths feed on a wide range of important plants and trees. White pine blister rust can kill young trees in only a couple of years. But it's not always easy to detect the presence of these destructive species just by looking at spots and bumps on a tree, or on the exterior of a cargo ship.

Now a new rapid DNA detection method developed at the University of British Columbia can identify these pests and pathogens in less than two hours, without using complicated processes or chemicals - a substantial time savings compared to the several days it currently takes to send samples to a lab for testing.

"Sometimes, a spot is just a spot," explains forestry professor Richard Hamelin, who designed the system with collaborators from UBC, Natural Resources Canada and the Canadian Food Inspection Agency. "Other times, it's a deadly fungus or an exotic bug that has hitched a ride on a shipping container and has the potential to decimate local parks, forests and farms. So you want to know as soon as possible what you're looking at, so that you can collect more samples to assess the extent of the invasion or begin to formulate a plan of action."

Hamelin's research focuses on using genomics to design better detection and monitoring methods for invasive pests and pathogens that threaten forests. For almost 25 years, he's been looking for a fast, accurate, inexpensive DNA test that can be performed even in places, like forests, without fast Internet or steady power supply.

He may have found it. The method, demonstrated in a preview last year for forestry policymakers in Ottawa, is straightforward. Tiny samples like parts of leaves or branches, or insect parts like wings and antennae, are dropped into a tube and popped into a small, battery-powered device (the Franklin thermo cycler, made by Philadelphia-based Biomeme). The device checks to see if these DNA fragments match the genomic material of the target species and generates a signal that can be visualized on a paired smartphone.

"With this system, we can tell with nearly 100 per cent accuracy if it is a match or not, if we're looking at a threatening invasive species or one that's benign," said Hamelin. "We can analyze up to nine samples from the same or different species at a time, and it's all lightweight enough--the thermocycler weighs only 1.3 kilos--to fit into your backpack with room to spare."

The method relies on PCR testing, the method that is currently also the gold standard for COVID-19. PCR testing effectively analyzes even tiny amounts of DNA by amplifying (through applying heating and cooling cycles) a portion of the genetic material to a level where it can be detected.

Hamelin's research was supported by Genome Canada, Genome BC and Genome Quebec and published in PLOS One. The UBC team, including lead author Arnaud Capron, tested this approach on species such as the Asian gypsy moth, white pine blister rust and sudden oak death pathogen, which are listed among the most destructive invasive pests worldwide.

"Our forestry, agriculture and horticulture are vital industries contributing billions of dollars to Canada's economy so it's essential that we protect them from their enemies," added Hamelin. "With early detection and steady surveillance, we can ensure that potential problems are nipped, so to speak, in the bud."

Cellular signal transmission is not only optimized for precision - it also includes a cost cap. The relationship between information and energy, a concept well established in physics and engineering, is likely to fundamentally shape cellular signalling networks. One of the questions addressed by researchers at the Max Planck Institute for Terrestrial Microbiology, headed by biophysicist Victor Sourjik, is: What enables reliable transmission of signals in the "noisy" cellular environment? The research team is studying signal transmission in baker's yeast (Saccharomyces cerevisiae), combining information theoretical approaches with quantitative experiments.

Precise signaling is crucial for the fitness of every living organism: whether during development or while communicating with a possible mating partner, only accurate transmission of received signals enables cells to trigger appropriate responses. In biological systems, random fluctuations of signals always lead to background noise, which can impede cell communication. Organisms must therefore have developed strategies to improve the accuracy of signal transmission in the presence of such interference. However, little is yet known about how noise suppression is achieved in cellular networks.

The pheromone signalling pathway of baker's yeast belongs to a class of MAPK (mitogen-activated protein kinase) signalling pathways, which in eukaryotes commonly play a key role in the transmission and translation of extracellular stimuli into intracellular responses such as cell differentiation, proliferation or stress responses.

That the pheromone signalling pathway of yeast contains negative feedback regulations could be seen as clear indication of selection for increased accuracy. Surprisingly, however, both theoretical and experimental analyses of the signalling pathway showed that its accuracy could be easily further improved by increasing the sensitivity of one of the negative feedbacks. So why this discrepancy between the potentially more efficient hypothetical and the natural design? In other words, why didn't yeast naturally optimize the system this way?

Costs versus benefits

The answer seems to lie in the cellular economics. The discrepancy disappears when the energy investment in the operation of the signalling pathway is also considered. "We were able to show that the core of the MAPK signalling pathway, the phosphorylation cycle, has measurable fitness costs. When these are taken into account, and the accuracy of the signal transduction is weighed against the energetic costs of the signalling pathway operation, the naturally observed design appears optimal," explains Alexander Anders, first author of the current publication.

"Here we observe a relation between information and energy, analogous to what is well established in physics and engineering sciences." says Victor Sourjik. "In biology, little attention has been paid to this interplay so far. Our work suggests that cost-benefit trade-off in information transfer must have been important in the evolution of cellular signalling systems. This helps us to better understand the evolutionary optimization of cellular signalling networks." How biology has solved this fundamental dilemma of information costs in other cases remains to be elucidated.

Scientists and historians working at McMaster University, the Mütter Museum and the University of Sydney have pieced together the genomes of old viruses that were used as vaccination strains during and after the American Civil War ultimately leading to the eradication of smallpox.

Smallpox was one of the most devastating viral diseases ever to strike humankind, killing about three out of every 10 people who were infected. Those who survived were frequently disabled, blind or disfigured.

The World Health Organization recently celebrated the 40th anniversary of the eradication of smallpox, the most successful campaign ever attempted. As researchers around the world work feverishly to develop a vaccine against COVID-19, the success of the campaign and the findings of this paper, outlined the journal Genome Biology, point to the value of vaccination, say researchers. They suggest other vaccines are waiting to be discovered among the viral relatives of today's influenza and coronaviruses.

"Understanding the history, the evolution and the ways in which these viruses can function as vaccines is hugely important in contemporary times," says evolutionary geneticist Hendrik Poinar, who is director of the McMaster Ancient DNA Centre, where the work was done, and a principal investigator at the university's Michael G. DeGroote Institute for Infectious Disease Research.

"This work points to the importance of looking at the diversity of these vaccine strains found out in the wild. We don't know how many could provide cross protection from a wide range of viruses, such as flus or coronaviruses," he says.

The concept of widespread vaccination dates back to 1796, when English physician Edward Jenner, known for his remarkable contributions to medicine, observed that exposure to a milder illness (called cowpox) thought to be transferred from cows with a similar pox-like illness on their udders to milkmaids, offered protection against future smallpox outbreaks. However, the method and source material used for early smallpox vaccinations remained unstandardized for over a century. While "cowpox" is often referenced as the source of the first vaccination, little had been known about the specific origins and diversity of the virus strains used in early smallpox vaccination programs

For their study, researchers used sophisticated techniques developed at the McMaster Ancient DNA Centre to reconstruct and analyse the genomes of virus fragments recovered from vaccination kits used during the Civil War era.

The kits, part of a medical collection at the Mütter Museum of the College of Physicians of Philadelphia, contained lancets and small glass plates for mixing fluid for vaccines that had been collected from blisters of deliberately infected subjects, and tin boxes with sliding lids to contain scab material.

The techniques used in this paper resulted in the successful recovery of viral molecules from both organic sources, such as scab material, but also from the non-destructive sampling of inorganic materials, such as tin boxes and glass slides, that contained no evidence of organic residues.

This finding opens a new possible field of study into medical history through the non-destructive examination of materials previously associated with biological samples.

The researchers were able to determine that in the 1860s and 1870s, medical practitioners in Philadelphia were using a vaccinia virus strain that was still being propagated in human subjects. The milder relative of the deadly smallpox pathogen was introduced into the body, usually by applying pus or scabs to a scratch or cut in the skin, where it helped recipients develop immunity to smallpox.

An overriding concern about vaccine design is how close - from an evolutionary standpoint- the vaccine strain must be to the one causing disease in order to prevent illness. Here, the vaccinia strains used for vaccination are in fact very distantly related to the virus that causes smallpox. The slow mutation rate of orthopox viruses (of which both vaccinia and variola are members) likely allows for this 'distant' protection.

"Vaccination is a wonderful process with a rich medical history that we should celebrate," says Ana Duggan, a former postdoc in the Department of Anthropology at McMaster, now at the Public Health Agency of Canada, who was lead researcher on the study. "Medical museums are incredible repositories of our past and of our collective history. The new tools we develop in this work allow us to begin to investigate how medical sources, procedures and techniques have changed through time."

Toshinori Chiba (ATR) and his collaborators have proposed an innovative new "Reciprocal Inhibition Model" of post-traumatic stress disorder (PTSD), which may aid considerably in its treatment. This model comprehensively explains the inhomogeneous nature of PTSD by addressing inter- and intra-patient variabilities at the neural, attentional, and symptom levels. This model may therefore pave the way for individual-tailored clinical PTSD treatment.

In the current climate where COVID-19 is pervasive, this new model of PTSD may be particularly pertinent. This is because patients recovering from COVID-19 are beginning to display "PTSD-like" adverse psychological effects related to fear and anxiety. Some example patients who have recovered from COVID-19, such as Stuart Gannaway (pseudonym), age 20, report symptoms such as increased fearfulness and mentally re-living their time in hospital over and over again. Others, such as Anabelle Hendy (pseudonym), age 34, report a different subset of psychological symptoms. Anabelle reflects "(after my COVID-19 diagnosis) I don't feel like myself anymore... I kind of feel like there is a veil between myself and reality, if that makes sense? I keep zoning out. I avoid talking about corona with people from work- I am worried they would be scared of me if they found out I had it, even though I am recovered now". A comprehensive explanation of why, after trauma, different patients develop different psychological symptoms is provided by the new "Reciprocal Inhibition Model". The proposals of this model pave the way for novel individual-specific clinical treatments. This model may therefore be of particular use under the current circumstances, where the number of physically-recovered yet mentally-still-traumatized Covid19 patients is increasing.

In movies, patients with PTSD are commonly portrayed as people who remain on high alert for threat and who often mentally re-live past traumatic events (similar to the symptoms reported by Stuart, above). While this is often true, paradoxically some patients with PTSD do their best to avoid threat and its associated memories, resulting in a dissociation from reality and a numbing of their emotions (similar to the symptoms reported by Anabelle, above). In line with these two clusters of symptoms, current clinical diagnostic criteria divide patients into two PTSD subtypes. However, the newly proposed "Reciprocal Inhibition Model" submits that differences between patients with PTSD may not be this black and white, but instead span the whole range of grey in between. It further proposes something not taken into account under current diagnostic criteria- that differences likely occur within individual patients so that each individual does not always consistently experience the same symptoms, but can switch between different states with different symptoms. Indeed, when the two recovered COVID-19 patients described above were further questioned, Stuart confides that he does sometimes find himself "zoning out" and Anabelle admits that she does sometimes find herself replaying her "darkest times with corona", indicating that these patients do sometimes switch between different subsets of symptoms.

What does "reciprocal inhibition" mean? To comprehend this, imagine two children fighting for your attention- each tries to cover the mouth of the other so that only the child who is currently winning can be heard clearly at any given time. This is similar to what happens in the brain during "reciprocal inhibition", where two neural regions alternate between dominating each other. The newly proposed model is called the "Reciprocal Inhibition Model" of PTSD, because, in this model, reciprocal inhibition between two distinct regions of the brain- the amygdala and the ventrolateral prefrontal cortex- is proposed to be what causes individual patients to switch between different states with different symptoms.

The "Reciprocal Inhibition Model" of PTSD predicts that when participants are in an amygdala dominant state, their attention will be biased towards threat causing them to experience relatively more fear-related symptoms, such as increased mental re-living of past traumatic events. Recovered COVID-19 patients, who display these kind of symptoms (such as Stuart, reported above), may be overly spending time in this state. On the other hand, when participants are in a ventrolateral prefrontal cortex dominant state, their attention will be biased away threat causing them to experience relatively more avoidance-related symptoms, such as a dissociation from reality and emotional numbing. Recovered COVID-19 patients who display these kind of symptoms (such as Anabelle, described above) may be overly spending time in this state. This model supposes that PTSD subtype diagnoses, that are still being used in the clinic today, might reflect categorical judgements based on the ratio of time that patients spend in each of these states.

In the paper which proposes the Reciprocal Inhibition Model of PTSD, experimental evidence is provided that supports the idea that attention alternates- even within the same individual patient- so that sometimes it is biased towards and sometimes it is biased away from threat. Furthermore, experimental and meta-analysis evidence is provided that supports the predicted relationship between attention and symptoms, and the predicted relationship between amygdala activity and symptoms. Other aspects of this model still need to be tested directly, but are well supported by existing literature.

If individual patients do alternate between states, as predicted in this model, then this has big implications for individual-tailored clinical treatments of PTSD. This is because different clinical treatments for PTSD have been shown to be more or less effective dependent on the amygdala reactivity of the patient (e.g. exposure therapy is less effective when amygdala reactivity is high). Until now, clinicians may have selected treatments for an individual patient with PTSD based on their diagnosed subtype (e.g. amygdala reactivity is thought to be exaggerated in the non-dissociative subtype, so people with this subtype might be less likely to be prescribed exposure therapy). However, if the predictions of the Reciprocal Inhibition Model are true, then this means that different treatments might be more or less effective for the same individual patient with PTSD depending on the state that they are currently in. This may also apply to patients experiencing emotional distress after COVID-19. Quick measurement of the patient's current state (symptoms could be used as a proxy) might inform clinicians of the most appropriate treatment for an individual patient during any given therapy session.

The Reciprocal Inhibition Model of PTSD includes novel proposals about the neural mechanisms that underlie PTSD. Elucidation of such mechanisms is vital if, for the treatment of PTSD, one wishes to use methods such as neurofeedback (where certain regions of the brain, or the way that certain regions of the brain work together, are "retrained") or transcranial magnetic stimulation (where, essentially, magnets are used to induce or decrease activity in targeted regions of the brain). Cutting-edge research is showing much benefit from these kinds of treatments and so further studies to confirm the neural mechanistic proposals of this model are imperative.