Tech

Whether at Oktoberfest, the movie theater or a shopping mall, the enticing aroma of soft pretzels is unmistakable. Now, researchers have identified the key compounds that give these twisted knots their distinctive scent. They report their results in ACS' Journal of Agricultural and Food Chemistry.

The characteristic taste, texture and smell of pretzels results in part from lye treatment of the pretzel dough, as well as from the coarse salt sprinkled on top. Like other foods, pretzels emit dozens of volatile compounds, but it can be difficult to determine which of these actually interact with odor receptors in the nose to trigger an aroma perception in the brain. In the past, researchers have used analytical techniques in combination with trained human sensory panelists to characterize the key odor compounds in wheat bread, rye bread and baguettes. Sebastian Schoenauer and Peter Schieberle wanted to identify the volatile compounds in soft pretzels that make their aroma different from that of the other baked goods.

Using trained sensory panelists, the team first determined that the brown crust, rather than the white crumb, of soft pretzels elicited the unique aroma. Then, the researchers extracted volatile compounds from the pretzel crust and separated them by gas chromatography. With their noses, they determined which ones had an odor, and identified them with mass spectrometry. Additional experiments with the panelists revealed that 4-hydroxy-2,5-dimethyl-3(2H)-furanone, which has a caramel-like odor, and 2-acetyl-1-pyrroline -- a roasty, popcorn-like smell -- were the key contributors to the pretzel aroma profile. The researchers then created a good approximation of the pretzel smell in the lab by combining the top six odor components. Although some of the same odorants were present in other baked goods, the overall amounts and ratios between components varied.

Russian scientists found that nanocrystal tungsten trioxide can be used instead of barium for X-ray examinations and also in cancer treatment. The results of the study are published in &laquoJournal of Nanomaterials».

Due to the physical-chemical properties of tungsten, in particular, the effective absorptive capacity of X-rays, its compounds are considered as a possible basis for creating a new class of contrast agents. This method can be used in computer tomography. Computer tomography (CT) is a method of visualizing the internal organs. The method is based on one-dimensional or two-dimensional projections obtained by passing of X-rays through tissues, when an X-ray source and a detector opposite to it simultaneously rotate around an object.

To obtain high-quality images, it is essential to have a visually distinct difference in the attenuation of X-rays between the organs. To differentiate organ, normal and pathological structures better, various contrast enhancement techniques are used. Usually this is done with the use of radiopaque agents that are injected in the form of solution. The greatest effect of attenuation of radiation is achieved with the use of chemical elements with a large mass of atom. When choosing such agents it is necessary to take into account five criteria for their clinical use in CT: effective radiopacity, selective distribution, lack of pharmacological and / or toxicological effects, in vitro and in vivo stability, cost and availability.

Today, only iodine and barium are used in radiography. However, in order to obtain a contrast X-ray image of the organ, one needs to take a relatively large amount of agent solution, which can cause discomfort and side effects.

Scientists from Kurnakov Institute of General and Inorganic Chemistry and the Institute of Theoretical and Experimental Biophysics RAS found that tungsten can be used instead of iodine and barium. They showed the biosafety of tungsten nanoparticles for human cells even in high concentrations, and also developed a scheme for the synthesis of highly crystallized tungsten trioxide nanoparticles, which can form the basis for creating a new radiopaque agent.

&laquoPreviously, we synthesized and investigated photochromic tungsten oxide nanoparticles, which have pronounced bactericidal activity against gram-positive and gram-negative bacteria, as well as selective photocatalytic activity against cancer cells, which can be used in perspective for photodynamic therapy of cancer. Our team works in two directions: development of a radiopaque agent and creation of a new class of photosensitizers for photodynamic cancer therapy», -- comments one of the authors of the study, Anton Popov.

Students think it is instructors' responsibility to ensure they don't surf the web in class, according to a new study.

In a recent mixed-method study, researchers from the University of Waterloo surveyed 478 undergraduates and 36 instructors on their perception of technology use in class.

The survey found that nine per cent of students thought course materials that could be seen on other students' laptops were distracting, whereas 49 per cent thought that non-course materials on other students' screens were distracting.

Although most students used technology in class to keep up with the course, some also used it to catch up on other classes, or because they felt bored and not engaged in the classroom. Students felt strongly that it is their right to use technology as they see fit, since they are adults paying for their education.

"While students felt that it was their choice to use the technology, they saw it as the instructors' responsibility to motivate them not to use it," says co-author Elena Neiterman, a School of Public Health and Health Systems professor.

Instructors saw technology as useful for providing accessible education, but it was also distracting for them: 68 percent were bothered by the use of phones in the classroom. Only 32 percent were bothered by the use of laptops and tablets, however, probably because they assume that laptops and tablets are used by students for class work. Some instructors also reported that off-task technology not only affected student learning, but also hindered their own ability to teach effectively.

"Some students said that instructors need to be more entertaining to keep students engaged in the classroom, but this a big ask, given that we are not employed in the entertainment industry," says Neiterman. "There is also a question of what we are preparing our students for: If we are training them for future employment, we might need to teach them to focus even if the class is 'boring.'"

The majority of instructors understood that banning technology in class is not an answer.

"Technology makes education accessible for students with disabilities, and many instructors use online tools such as Ted Talks and YouTube videos in class," says Neiterman. "Our students use technology to take notes - students today don't even learn cursive in school. "

She added that banning technology in the classroom would not be lawful because it would expose students who use technology to accommodate a disability. Even if it were possible, however, it is not feasible. "A ban means policing," says Neiterman. "With larger class sizes, who is going to police students to ensure that they do not use technology?"

The study, titled "A Mixed Blessing? Students' and Instructors' Perspectives about Off-task Technology Use in the Academic Classroom" was co-authored by Elena Neiterman and Christine Zaza and published in the Canadian Journal for the Scholarship of the Teaching and Learning.

Researchers from the University of Granada, the Andalusian Institute of Agricultural Research and Training, Fishing, Food and Organic Production (IFAPA), and the Pyrenean Institute of Ecology of the Spanish National Research Council (CSIC) have verified that the thinning technique is effective as an alternative approach in the recovery and maintenance of forest ecosystems dealing with extreme climates. The thinning method consists of reducing the number of trees in a given area, so that those remaining are able to access more resources.

The researchers validated this technique using a novel method based on taking high-resolution measurements in the variations of the diameters of tree trunks. The method contributes to a better understanding of the short-term relationships between climatic changes and tree stem growth. To date, the technique commonly used has been to measure the width of the trunk's rings, but this is ineffective for discerning growth over a short time scale.

Forest thinning consists of reducing the density of trees per hectare, to thus decrease the competition for available resources and improve the growth of the remaining trees, rendering them less vulnerable to water stress. The researchers have set out this technique in a recent paper entitled "Using stem diameter variations to detect and quantify growth and relationships with climatic variables on a gradient of thinned Aleppo pines" published in the journal Forest Ecology and Management. They position it as a viable alternative in the fight against climate change in certain Mediterranean areas, demonstrating that the growth of forests improves when there is less competition between individual trees.

These experts analysed the evolution of the trees over time. IFAPA researcher Francisco Bruno Navarro Reyes, co-author of the article, explains: "We have monitored the daily contractions and dilations of the trunks over the course of three years, to assess whether this technique triggers earlier growth in Spring and lengthens the period through to the autumn, effectively prolonging the period during which the trees develop."

Fewer pine trees, improved growth

The land where the experiment and observations were conducted--Cortijo del Conejo, Cortijo Albarrán and Cortijo Becerra, in Guadix, Province of Granada--belongs to the Ministry of Agriculture, Livestock, Fisheries and Sustainable Development, and was recently declared a critical area for research on management of the natural environment in south-eastern Spain. At these sites, records have been kept for over 20 years on the climatic variables of the area. By examining factors such as humidity and air temperature, radiation, or vapour-pressure deficit, the researchers determined how the management of such areas can affect the direct response between trees and climate.

The scope of the study covered 16 plots measuring 20m x 20m planted in 1995 with Pinus halepensis (Aleppo pine), to a density of about 1,500 per hectare, this species being among the most commonly found in the Mediterranean area. Ten years after the pines were planted, the researchers commenced the thinning process, controlling the relative degree of thinning in each plot and reducing the original density to 800, 400, and 250 trees per hectare, respectively.

The measurements were made using digital dendrometers, which very accurately record variations in trunk dimensions and provide precise information about secondary tree growth in relation to climatic variables and water stress. Using this technology, the experts successfully established the effects of these variables on the cumulative growth of the pines (measured daily, monthly, annually and in total) more accurately than with other methods used in the past, such as band dendrometers or tree ring analysis.

In addition, by means of mathematical and statistical analyses, the researchers were able to identify how individual tree-environment relationships operate, reflecting their adaptation to the change in density. In those treatments with lower a concentration of trees, the pines grew much better. Hence, the study has confirmed that, when competition for resources is reduced, development and growth are longer and more effective.

After five years of thinning, the dendrometers were installed in each plot to monitor secondary tree growth--the daily variation of the trunks, the accumulated growth, and the maximum daily contraction, as well as the number of days of actual development during a three-year period. This information, together with the correlation of climatic variables, revealed that trees in the plots subjected to the greatest thinning showed less vulnerability to drought, greater recovery capacity after drought, and improved climatic sensitivity. They also presented greater efficiency in the use of resources and, therefore, better adaptation to the environment and greater resilience to change.

The various stages of the research were funded by Spain's National Institute for Agricultural and Food Research and Technology (INIA), European Union Feder funding, and the Andalusian Environment and Water Agency, within the project "Áreas pasto-cortafuegos como herramienta de selvicultura preventiva de incendios en las tierras forestales mediterráneas".

Researchers at the University of Illinois at Chicago and AbbVie Inc. have developed a novel device that will help scientists and pharmaceutical companies more effectively screen and test formation of drug substance - active pharmaceutical ingredient (API).

Meenesh R. Singh, an assistant professor with UIC's chemical engineering department, along with UIC graduate student Paria Coliaie and AbbVie scientists Manish S. Kelkar and Nandkishor K. Nere developed a controlled microfluidic crystallization device to improve the screening process that pharmaceutical companies use to identify the most stable crystalline form of APIs and to scale up the crystallization of stable forms.

The work, titled "Continuous-Flow, Well-Mixed, Microfluidic Crystallization Device for Screening of Polymorphs, Morphologies, and Crystallization Kinetics at Controlled Supersaturation," was published in Royal Society of Chemistry's peer-reviewed journal, Lab on a Chip.

Singh referred to a UK Office of Health Economics report indicating that it currently takes around 10 years and billions of dollars to bring a new drug to market after a molecule is identified to treat a disease. A significant portion of that decade is invested in process development, along with ongoing clinical trials, where scientists screen the different polymorphic forms of the APIs and develop robust processes to manufacture the stable form with the acceptable physical properties to turn that into pills or tablets.

The industry currently uses microtiter plates and droplet-based microfluidic devices to screen these different forms, but Singh noted these devices run into problems due to depletion of supersaturation, which is a driver for crystallization. He explained that as the nucleation process occurs and the crystals grow in the microtiter plate, they use up the initial supply of the API causing supersaturation to deplete and bias the screening results. The incomplete understanding of the polymorphic landscape of API obtained from the microtiter plates poses a huge risk when companies move to scale-up and technology transfer to manufacture APIs in larger vessels called crystallizers and subsequent process equipment such as filters and dryers.

To combat this issue, the investigators created a continuous-flow, well mixed, microfluidic device called cyclone mixer that consists of small valves with multiple inlets that work together to create a vortex in the device to ensure the solution is well mixed and keeps the supersaturation constant by continuing to supply the device with an API solution. The API crystals are captured in the cyclone mixer and the device automatically shuts down after enough of the API has been created.

"What we have done is, develop a screening device that simulates conditions of an industrial crystallizer," Coliaie said. "Most of the devices currently on the market see the supersaturation decrease with the time that may not provide a complete picture of crystal form landscape."

Kelkar notes that this device is easy to fabricate using a commercial 3D printer. "One 3D printed device cost just a few cents which offers us a lot of flexibility to make changes in the design to screen salts, hydrates, and solvates of the crystalline APIs."

As described in their research paper, the investigators tested the device to screen anthranilic acid whose derivates are anti-inflammatory drugs. The device can also be used to screen agrochemicals, semiconductors, catalysts, and other specialty chemicals for other industries in a more consistent and stable manner than is currently available.

Singh added the new device can also help pharmaceutical companies to move from batch-based production to continuous manufacturing, which the FDA hopes to spur advancements in robust API manufacturing at lower costs. Nere noted the device itself is actually a mini prototype of a continuous manufacturing model and will allow companies to see exactly how their APIs will crystallize under those conditions.

"The time and money required for an API process development and manufacture are immense. Robust manufacturing of quality APIs is essential for the timely delivery of drugs to patients," Nere said.

"We have developed a novel microfluidic device that can quickly and automatically screen various forms of APIs at controlled conditions, which will increase the efficiency of manufacturing process development," Singh added.

Many of the immune defence reactions are launched in the lymph nodes. For instance, small, foreign molecules that pass through the skin are directed through lymphatic vessels to the draining lymph node where they are presented to white blood cells. However, the reticular conduits inside the lymph node are so small that large molecules cannot be transported through the system. Therefore, it has been thought that subcutaneously administered antibodies pass through the lymphatic vessels straight into the blood circulation bypassing the lymph nodes entirely.

Researchers from the University of Turku, Finland, have discovered in an experimental model that a new mechanism allows the antibodies to enter the lymph node directly.

Doctoral Candidates Laura Kähäri and Ruth Fair-Mäkelä as well as Adjunct Professor Kaisa Auvinen from the research group of Professor Marko Salmi discovered that antibodies pass through lymphatic endothelial cells covering the surface of the lymph node via a previously unknown mechanism.

- It was a surprise to discover subcutaneously administered antibodies in the parenchyma of the draining lymph node. The delivery of the antibody was extremely efficient. It was transported from the skin into the lymph node in just a few seconds. When using a small dose, the antibody was found only in the draining lymph node in addition to the site of administration, and nowhere else in the body, says Kähäri.

- It's exciting that the antibodies are delivered in an intact form to the targeted draining lymph node. By using this new delivery route, we can activate or inhibit inflammation locally, adds Fair-Mäkelä.

Significant Potential for Applications

Antibodies are commonly used in treating inflammatory diseases, cancers and several other illnesses. The medication is often administered to the patient intravenously so that large quantities of the antibody spreads throughout the body via the blood circulation.

The novel discovery can have a far-reaching impact on medicine. In vaccinations, for instance, the immune response is boosted with relatively non-specific adjuvants that trigger the inflammation in the draining lymph node. On the basis of this study, the same effect could be induced by locally administered and well-characterised antibodies.

- Also immunotherapeutic checkpoint inhibitors that have revolutionised cancer treatment could be locally administered in certain cases. When compared with the current administration through the blood circulation, local subcutaneous administration would require only a fraction of the drug amount used at the moment. In addition to the cost benefits, this should eliminate the adverse effects in other parts of the body, Kähäri and Fair-Mäkelä speculate.

Both Kähäri and Fair-Mäkelä will focus their future studies especially on the different potential applications of the discovery.

Study identifies factors that most affect older people's vulnerability during extreme temperatures

Older people may have difficulty accessing facilities designed to help keep cool during hot weather

Greater awareness of impact of extreme temperatures on individual health has biggest impact, according to study from University of Warwick

Interview data shows vulnerability can vary significantly between individuals

Efforts to support older people during extreme heat should focus on those who lack independence or have pre-existing health issues, according to an expert from the University of Warwick.

New research shows that having locations where older people can keep cool plays a key role in reducing their vulnerability to extreme heat, but that older people may find them difficult to access or have limited ability to travel to them.

It comes as countries in Europe are experiencing a potentially record-breaking heatwave this week.

Dr Raquel Nunes from Warwick Medical School has developed a new assessment to quantify an individual's vulnerability to extreme hot and cold weather based upon their personal situation and resources. Detailed in a recent paper for the International Journal of Environmental Health Research, it reveals that vulnerability to temperature extremes can vary by individual, but there are factors that are more significant than others.

Older adults (aged 65+) are considered a high risk group to the impacts of extreme temperatures. Direct and indirect effects of heatwaves and cold waves are associated with an increase in respiratory and cardiovascular diseases, and impact on the mortality and morbidity of older adults.

Most existing definitions and assessments of vulnerability examine general risks for older adults, but few focus on specific issues such as hot or cold weather.

Using an asset-based approach, Dr Nunes developed a General Vulnerability Index to establish the everyday vulnerabilities for older adults. This used a broad mix of human, financial, physical, place-based and social assets, such as health status, quality of life, education level, age of their home, access to public services, and others.

She then developed Specified Vulnerability Assessments for cold weather and heatwaves that assessed factors that specifically related to vulnerability to those two risks, such as income constraints, lack of housing insulation, lack of heating and cooling devices.

Using data obtained through interviews with older adults living in Lisbon, Portugal, Dr Nunes found that there can be different levels of general and specified vulnerability for the same person - so an individual might have a high general vulnerability, but at the same time have low vulnerability to extreme heat and high vulnerability to extreme cold.

In particular, increased pressure on financial (i.e. income, pensions), human (i.e. health status and health literacy) and physical assets (i.e. lack of housing insulation) of the individual were found to have the most significant effect on their vulnerability. This reflects their ability to take action to keep cool or warm during heatwaves and cold weather.

Dr Raquel Nunes, a senior research fellow at Warwick Medical School, said: "Just because an individual may be older doesn't necessarily mean they are more vulnerable. We need to look at the different facets of their lives, the different assets available to them and the things that are within their own control. There are a lot of things that individuals can do to reduce their vulnerability.

"One way is to better understand the risks and impacts of extreme temperatures, to use alternative strategies to keep cool and warm during extreme temperatures, such as leaving the house more to keep cool and warm. Having more social contacts (i.e. neighbours, family, friends) can help older people reduce social isolation and enable them to exchange advice regarding extreme temperatures. There are ways to make their homes more comfortable during extreme temperatures that they may not be aware of, such as schemes that help older people to pay their electricity or gas bills. And being more aware of the risks that heat and cold might pose to them because of specific health conditions they might have.

"Everyone can do something at any age. If you are more aware of the risks around you and if you obtain information from health professionals or family members, you'll definitely be more prepared to deal with these kinds of events."

The assessments will be useful to researchers, policymakers and practitioners in local authorities and health and social care providers, to help them understand the causes of vulnerability and how an individual's vulnerability varies depending on different risks they are exposed to. This will in turn help tackle the most important factors shaping vulnerability, as well as to plan and implement strategies to reduce vulnerability.

Dr Nunes adds: "These findings also have implications for improving public health policy and practice. As they highlighted high levels of trust and support older people receive from their local authority, there are opportunities for an integrated approach where health and social care professionals, housing officers and city planners work together under the 'same roof' using a person- or community-centred approach to provide advice and care to the whole population, not only to older people, for reducing vulnerability to extreme temperatures.

"What I've tried to do by using an assets-based approach is to depict which factors have more impact on vulnerability, particularly where it concerns mortality or morbidity. Using physical, human, financial, social and place-based assets allows you to depict for certain individuals what specific factors are making them vulnerable.

"Acting on each of these types of assets to reduce vulnerability is possible but we need to be proactive and not wait for older people to ask for help."

Nanowires promise to make LEDs more colorful and solar cells more efficient, in addition to speeding up computers. That is, provided that the tiny semiconductors convert electric energy into light, and vice versa, at the right wavelengths. A research team at the German Helmholtz-Zentrum Dresden-Rossendorf (HZDR) has managed to produce nanowires with operating wavelengths that can be freely selected over a wide range - simply by altering the shell structure. Fine-tuned nanowires could take on several roles in an optoelectronic component. That would make the components more powerful, more cost-effective, and easier to integrate, as the team reports in Nature Communications (doi: 10.1038/s41467-019-10654-7).

Nanowires are extremely versatile. The tiny elements can be used for miniaturized photonic and electronic components in nanotechnology. Applications include optical circuits on chips, novel sensors, LEDs, solar cells and innovative quantum technologies. It is the free-standing nanowires that ensure the compatibility of more recent semiconductor technologies with conventional silicon-based technologies. Since contact to the silicon substrate is tiny, they surmount typical difficulties in combining different materials.

For their study, which lasted several years, the Dresden researchers first set about growing nanowires from the semiconductor material gallium arsenide on silicon substrates. The next step involved enclosing the wafer-thin wires in another layer of material to which they added indium as an additional element. Their goal: the mismatched crystal structure of the materials was intended to induce a mechanical strain in the wire core, which changes the electronic properties of gallium arsenide. For instance, the semiconductor bandgap becomes smaller and the electrons become more mobile. To magnify this effect, the scientists kept adding more indium to the shell, or increased the shell's thickness. The result went way beyond expectations.

Taking a known effect to extremes

"What we did was take a known effect to extremes," explained Emmanouil Dimakis, leader of the study that involved researchers from HZDR, TU Dresden and DESY in Hamburg. "The seven percent of strain achieved was tremendous."

At this level of strain, Dimakis had expected to see disorders occurring in the semiconductors: in their experience, the wire core bends or defects arise. The researchers believe that the special experimental conditions were the reason for the absence of such disorders: First, they grew extremely thin gallium arsenide wires - around five thousand times finer than a human hair. Second, the team managed to produce the wire shell at unusually low temperatures. Surface diffusion of atoms is then more or less frozen, forcing the shell to grow evenly around the core. The team of researchers reinforced their discovery by conducting several independent series of measurements at facilities in Dresden, as well as at the high-brilliance X-ray light sources PETRA III in Hamburg and Diamond in England.

The extraordinary results led the researchers to undertake further investigations: "We shifted our focus to the question of what triggers the extremely high strain in the nanowire core, and how this can be used for certain applications," Dimakis recollected. "Scientists have been aware of gallium arsenide as a material for years, but nanowires are special. A material may exhibit completely new properties at the nanoscale."

Potential applications for fiber-optic networks

The researchers realized that the high strain let them shift the bandgap of the gallium arsenide semiconductor to very low energies, making it compatible even for wavelengths of fiber-optic networks. A technological milestone. After all, this spectral range could previously only be achieved via special alloys containing indium, which caused a number of technological problems due to the material mix.

High-precision methods are required to produce nanowires. Four years ago, a special system was installed at HZDR for this purpose: the molecular beam epitaxy laboratory. The self-catalyzed growth of nanowires from beams of atoms or molecules is achieved in the lab; the beams are directed onto silicon substrates in ultra-high-vacuum. Emmanouil Dimakis played a major part in setting up the lab. Most of the studies reported in the current publication were carried out by Leila Balaghi as part of her doctorate.

Although largely paralyzed, ALS patients can communicate through eye-tracking devices because they retain eye movement until the disease's late stages. Yet, how some motor neurons resist ALS to allow for this movement has been a mystery.

Now, scientists have developed a stem-cell-based modeling system that identifies how some neurons are resistant to ALS--a breakthrough that offers potential for battling neurodegeneration.

"Some neurons, notably the ones used for eye movement, are better at fighting ALS than are those that control other muscle groups," explains Esteban Mazzoni, a professor in New York University's Department of Biology and the senior author of the paper, which appears in the journal eLife. "These findings help elucidate the differences between neuronal types that successfully battle ALS and those that succumb to the disease."

"Having identified a potential mechanism that protects some parts of the body, we are now working on making all neurons ALS resistant," he adds. "Specifically, we are striving to identify the different mechanisms that paralyze some parts of the body and leave others fully functional."

Underlying this research are well-established differences in neuronal responses: spinal motor neurons (SpMN), which control much of our muscle movement, progressively degenerate while a subset of cranial motor neurons (CrMN), which control eye movement, maintain function until the late stages of ALS.

With this in mind, the paper's authors sought to better understand how the neurons that control eye movement survive while those that control the rest of the body's movements die.

Using stem cells from mice, the researchers developed a modeling system to generate motor neurons that were both rendered dysfunctional by and resistant to ALS. They then studied their properties in order to identify specific cellular features that could be responsible for keeping eye motor neurons alive.

Specifically, they found that CrMNs are better able to discard damaged proteins than are SpMNs. Moreover, the scientists discovered, CrMNs are better able to withstand cellular stress brought on by ALS than are SpMNs, allowing neurons that control eye movement to function normally for longer periods than those that manage other muscular activity.

Computer scientists are focused on adding enhanced functionality to make the "reality" in virtual reality (VR) environments highly believable. A key aspect of VR is to enable remote social interactions and the possibility of making it more immersive than any prior telecommunication media. Researchers from Facebook Reality Labs (FRL) have developed a revolutionary system called Codec Avatars that gives VR users the ability to interact with others while representing themselves with lifelike avatars precisely animated in real-time. The researchers aim to build the future of connection within virtual reality, and eventually, augmented reality by delivering the most socially engaged experience possible for users in the VR world.

To date, highly photo-realistic avatars rendered in real-time have been achieved and used frequently in computer animation, whereby actors are equipped with sensors that are optimally placed to computationally capture geometric details of their faces and facial expressions. This sensor technology, however, is not compatible with existing VR headset designs or platforms, and typical VR headsets obstruct different parts of the face so that complete facial capture technology is difficult. Therefore, these systems are more suitable for one-way performances rather than two-way interactions where two or more people are all wearing VR headsets.

"Our work demonstrates that it is possible to precisely animate photorealistic avatars from cameras closely mounted on a VR headset," says lead author Shih-En Wei, research scientist at Facebook. Wei and collaborators have configured a headset with minimum sensors for facial capture, and their system enables two-way, authentic social interaction in VR.

Wei and his colleagues from Facebook will demonstrate their VR real-time facial animation system at SIGGRAPH 2019, held 28 July-1 August in Los Angeles. This annual gathering showcases the world's leading professionals, academics, and creative minds at the forefront of computer graphics and interactive techniques.

In this work, the researchers present a system that can animate avatar heads with highly detailed personal likeness by precisely tracking users' real-time facial expressions using a minimum set of headset-mounted cameras (HMC). They address two key challenges: difficult camera views on the HMC and the large appearance differences between images captured from the headset cameras and renderings of the person's lifelike avatar.

The team developed a "training" headset prototype, which not only has cameras on the regular tracking headset for real-time animation, but is additionally equipped with cameras at more accommodating positions for ideal face-tracking. The researchers present an artificial intelligence technique based on Generative Adversarial Networks (GANs) that performs consistent multi-view image style translation to automatically convert HMC infrared images to images that look like a rendered avatar but with the same facial expression of the person.

"By comparing these converted images using every pixel--not just sparse facial features--and the renderings of the 3D avatar," notes Wei, "we can precisely map between the images from tracking headset and the status of the 3D avatar through differentiable rendering. After the mapping is established, we train a neural network to predict face parameter from a minimal set of camera images in real time."

They demonstrated a variety of examples in this work, and were able to show that their method can find high-quality mappings even for subtle facial expressions on the upper face-an area that is very difficult to capture--where the camera angle from the headset is askew and too close to the subject. The researchers also show extremely detailed facial capture, including subtle differences in tongues, teeth, and eyes, where the avatar does not have detailed geometry.

In addition to animating the avatars in VR, the FRL team is also building systems that may one day enable people to quickly and easily create their avatars from just a few images or videos. While today's Codec Avatars are created automatically, the process requires a large system of cameras and microphones to capture the individual. FRL also aims to create and animate full bodies for expressing more complete social signals. While this technology is years away from reaching consumer headsets, the research group is already working through possible solutions to keep avatar data safe and ensure avatars can only be accessed by the people they represent.

Stem cells are not only key players in tissue regeneration, they are also capable of taking direct action against bacteria. This is the finding of a study conducted by researchers from Charité - Universitätsmedizin Berlin and the Max Planck Institute for Infection Biology, which describes what happens during a Helicobacter pylori infection of the human stomach. By actively fighting the colonizing bacteria, gastric stem cells protect themselves against damage that can lead to cancer. Results from this study have been published in Nature Cell Biology*.

Approximately 50 percent of the world's population are infected with the bacterium Helicobacter pylori, the most important risk factor for gastric cancer. It colonizes the gastric epithelium and can cause DNA damage in epithelial cells. As the majority of affected cells are short-lived and replaced within a matter of days, such damage is unlikely to have serious consequences. However, the effects can be much more severe if the bacterium attacks the stem cells, which have a much longer lifespan. They are located deep inside the gastric gland and produce daughter cells destined to replace the mucosal cells at the surface. If the DNA of these stem cells is damaged by H. pylori, it may lead to the development of gastric cancer.

The researchers working on this new study were able to show that gastric stem cells employ active measures to fend off the bacteria. "Our animal model enabled us to observe that stem cells release a protein known as intelectin 1 into their surroundings," explains the study's first author, Dr. Michael Sigal, a BIH Charité Clinician Scientist based at the Medical Department, Division of Hepatology and Gastroenterology on Campus Charité Mitte. "Intelectin 1 binds to the surface of Helicobacter pylori, causing the bacteria to clump together. This stops them from entering the gastric gland cavity and damaging the stem cells located there."

The production of intelectin 1 is triggered by R-spondin 3, a signaling molecule which was previously shown to stimulate stem cell proliferation. R-spondin 3 secretion increases as soon as the body recognizes damage such as that caused by H. pylori. Summarizing the researchers' findings, the study's last author, Prof. Dr. Thomas Meyer, Director of the Max Planck Institute for Infection Biology, says: "The body responds to Helicobacter pylori infection by releasing a signaling molecule that stimulates the proliferation of gastric stem cells and promotes tissue regeneration. The same messenger molecule also causes neighboring gastric stem cells to release antibacterial proteins that actively protect the stem cell niche against the invasion of pathogens. This mechanism enables the body to prevent the more serious consequences of infection, such as gastric ulcers and gastric cancer."

"We hope to use our findings to identify those Helicobacter pylori-infected patients in whom this protective mechanism is out of balance," adds Dr. Sigal. "The idea is then to offer treatment options specifically to these people." The researchers suspect that these patients are at a particularly high risk of developing stomach cancer as a result of chronic Helicobacter infection. Therefore, they are planning to conduct further studies to investigate the link between stem cell-based protection mechanisms and cancer development - not just in the stomach, but throughout the gastrointestinal tract.

One way that heat damages electronic equipment is it makes components expand at different rates, resulting in forces that cause micro-cracking and distortion. Plastic components and circuit boards are particularly prone to damage due to changes in volume during heating and cooling cycles. But if a material could be incorporated into the components that compensates for the expansion, the stresses would be reduced and their lifetime increased.

Everybody knows one material that behaves like this: liquid water expands when it freezes and ice contracts when it melts. But liquid water and electronics don't mix well - instead, what's needed is a solid with "negative thermal expansion" (NTE).

Although such materials have been known since the 1960s, a number of challenges had to be overcome before the concept would be broadly useful and commercially viable. In terms of both materials and function, these efforts have only had limited success. The experimental materials had been produced under specialized laboratory conditions using expensive equipment; and even then, the temperature and pressure ranges in which they would exhibit NTE were well outside normal everyday conditions. Moreover, the amount they expanded and contracted depended on the direction, which induced internal stresses that changed their structure, meaning that the NTE property would not last longer than a few heating and cooling cycles.

A research team led by Koshi Takenaka of Nagoya University has succeeded in overcoming these materials-engineering challenges. Inspired by the series of work by Noriaki Sato, also of Nagoya University - whose discovery last year of superconductivity in quasicrystals was considered one of the top ten physics discoveries of the year by Physics World magazine - Professor Takenaka took the rare earth element samarium and its sulfide, samarium monosulfide (SmS), which is known to change phase from the "black phase" to the smaller-volume "golden phase". The problem was to tune the range of temperatures at which the phase transition occurs. The team's solution was to replace a small proportion of samarium atoms with another rare earth element, giving Sm1-xRxS, where "R" is any one of the rare earth elements cerium (Ce), neodymium (Nd), praseodymium (Pr) or yttrium (Y). The fraction x the team used was typically 0.2, except for yttrium. These materials showed "giant negative thermal expansion" of up to 8% at ordinary room pressure and a useful range of temperatures (around 150 degrees) including at room temperature and above (Fig. 1). Cerium is the star candidate here because it is relatively cheap.

The nature of the phase transition is such that the materials can be powdered into very small crystal sizes around a micron on a side without losing their negative expansion property. This broadens the industrial applications, particularly within electronics.

While the Nagoya University group's engineering achievement is impressive, how the negative expansion works is fascinating from a fundamental physics viewpoint. During the black-golden transition, the crystal structure stays the same but the atoms get closer together: the unit cell size becomes smaller because (as is very likely but perhaps not yet 100% certain) the electron structure of the samarium atoms changes and makes them smaller - a process of intra-atomic charge transfer called a "valence transition" or "valence fluctuation" within the samarium atoms (Fig. 2). "My impression," says Professor Takenaka, "is that the correlation between the lattice volume and the electron structure of samarium is experimentally verified for this class of sulfides."

More specifically, in the black (lower temperature) phase, the electron configuration of the samarium atoms is (4f)6, meaning that in their outermost shell they have 6 electrons in the f orbitals (with s, p and d orbitals filled); while in the golden phase the electronic configuration is (4f)5(5d)1 -an electron has moved out of a 4f orbital into a 5d orbital. Although a "higher" shell is starting to be occupied, it turns out - through a quirk of the Pauli Exclusion Principle - that the second case gives a smaller atom size, leading to a smaller crystal size and negative expansion.

But this is only part of the fundamental picture. In the black phase, samarium sulfide and its doped offshoots are insulators - they do not conduct electricity; while in the golden phase they turn into conductors (i.e. metals). This is suggesting that during the black-golden phase transition the band structure of the whole crystal is influencing the valance transition within the samarium atoms. Although nobody has done the theoretical calculations for the doped samarium sulfides made by Professor Takenaka's group, a previous theoretical study has indicated that when electrons leave the samarium atoms' f orbital, they leave behind a positively charged "hole" which itself interacts repulsively with holes in the crystal's conduction band, affecting their exchange interaction. This becomes a cooperative effect that then drives the valence transition in the samarium atoms. The exact mechanism, though, is not well understood.

Nevertheless, the Nagoya University-led group's achievement is one of engineering, not pure physics. "What is important for many engineers is the ability to use the material to reduce device failure due to thermal expansion," explains Professor Takenaka. "In short, in a certain temperature range - the temperature range in which the intended device operates, typically an interval of dozens of degrees or more - the volume needs to gradually decrease with a rise in temperature and increase as the temperature falls. Of course, I also know that volume expansion on cooling during a phase transition [like water freezing] is a common case for many materials. However, if the volume changes in a very narrow temperature range, there is no engineering value. The present achievement is the result of material engineering, not pure physics."

Perhaps it even heralds a new "golden" age for electronics.

WASHINGTON, D.C., June 25, 2019 -- A new mathematical model of the structure of networks could help find new cancer drugs, speed up traffic flow and combat sexually transmitted disease.

Although the three challenges seem diverse, they all could benefit from a theory that helps to uncover unknown information about a network by analyzing its structure. The study was published in the journal Chaos, from AIP Publishing.

An example of how filling in missing links could be useful is in choosing a genetic target for a cancer drug, said team member Michael Small, from the University of Western Australia.

"Say you have a network of genes that are somehow connected, and there are some known drug targets. But if you don't know all the genes, you would like to make guesses at information that you don't have to work out what might be other likely targets to investigate," Small said.

Successful link prediction algorithms already exist for certain types of networks, but the researchers analyzed differently structured networks to come up with their alternative algorithm.

An example of traditional link prediction might be a social network suggesting friends with which to connect. Two people who share a friend are likely to themselves be friends with a direct connection. Adding this third connection creates a triangle, which is a structure where existing algorithms focus.

In contrast, the authors focused on treelike networks, which have many branches but very few cross links between branches. They studied three example datasets: the social network Twitter, a water distribution network and a sexual contact network.

They found these three treelike networks could be characterized by a number of parameters, such as the average distance between branch points in the network, the size of loops and a comparison of the number of links that adjacent nodes have -- a measure of the network's regularity describing heterogeneity.

The authors then developed an algorithm that suggested links that would preserve these characteristics of the network.

They tested this approach by taking a known network and removing links from it and seeing if the algorithm could predict where the missing links should be.

The team found the algorithm performed better (around 44% for the Twitter network, around 15% for the sexual contact network and around 4% for the water distribution network) for treelike networks than most of conventional algorithms which rely on other parameters, such as assuming highly connected individuals will attract more connections (known as preferential attachment) or building lots of triangular connections (known as clustering).

Author Keke Shang attributes the team's success to thinking about examples of real-world networks.

"I hope we can make network technology serve our lives better," he said.

Strengthening biosecurity is widely considered the best strategy to reduce the devastating impact of disease outbreaks in the multi-billion-dollar global swine industry, but successfully doing so all comes down to human decision-making, a University of Vermont study shows.

The study, published June 25, 2019 in Frontiers in Veterinary Science, is the first of its kind to include human behavior in infectious disease outbreak projections - a critical element that has largely been ignored in previous epidemiological models. Incorporating theories of behavior change, communications and economic decision-making into disease models gives a more accurate depiction of how outbreak scenarios play out in the real-world to better inform prevention and control strategies.

"We've come to realize that human decisions are critical to this picture," said Gabriela Bucini, a postdoctoral researcher in UVM's Dept. of Plant and Soil Science and lead author of the study. "We are talking about incredibly virulent diseases that can be transmitted in tiny amounts of feed and manure. Ultimately, controlling these diseases is up to the people in the production system who decide whether or not to invest and comply with biosecurity practices."

Seeking to understand the role of human behavior in animal disease outbreaks, the researchers designed a series of video games in which players assumed the roles of hog farmers and were required to make risk management decisions in different situations. Observing how players responded to various biosecurity threats provided data used to simulate the spread of Porcine Epidemic Diarrhea virus (PEDv) - one of the most severe infectious diseases in the U.S. swine industry - in a regional, real-world hog production system.

The number of pigs that contracted PEDv was shown to be highly dependent on the risk attitudes of the farmers and producers in the system and a relatively small shift in risk attitudes could have a significant impact on disease incidence. According to the study, getting just 10 percent of risk tolerant farmers to adopt a risk averse position with stronger biosecurity measures reduced the total incidence of PEDv by 19 percent. Keeping the disease under control required at least 40 percent of risk-takers to change their attitudes.

"The risk attitudes and human decisions that we're incorporating in the model are really powerful," said Scott Merrill, co-author and researcher in the Dept. of Plant and Soil Science and Gund Institute for the Environment. "If we can change the way people behave, then we have a chance to make some dramatic impacts and avoid a devastating outbreak."

Getting Serious About Games

Merrill and Bucini are part of a team of researchers in UVM's Social Ecological Gaming and Simulation (SEGS) Lab who are designing interactive "serious" games and computational models to understand complex systems. Developed by Merrill, along with Chris Koliba and Asim Zia in the Dept. of Community Development and Applied Economics and Gund Institute for the Environment, the SEGS Lab places research subjects in a virtual world where researchers can monitor their behavior - an approach that may help eliminate some of the biases that can occur with traditional surveys.

Their work in the area of animal disease biosecurity is part of a $7.4 million multi-institutional biosecurity initiative led by UVM animal science researcher Julie Smith that's aiming to inform policies that collectively reduce the impact of pests and diseases on food-producing livestock in the U.S.

The PEDv outbreak model is grounded in data derived from the biosecurity video games, which found that people behaved differently depending on the type of information they received and how it was presented. In one game, players were given several different risk scenarios and had to decide whether to maximize their profit or minimize their risk. Players presented with a 5 percent risk of their animals getting sick if they ignored biosecurity protocols complied only 30 percent of the time. However, when the risk level was presented visually as "low risk" on a threat gauge with some built in uncertainty, rather than numerically, players complied over 80 percent of the time.

"A simple thing like going out the wrong barn door can have a huge impact," said Merrill. "With the game data, we can see big differences in the economic and disease dynamics as we change the type of information we're delivering, and the way it's delivered."

Rising Global Threat

Infectious diseases like PEDv pose a continuous risk to U.S. hog producers, one that is increasing with the consolidation and globalization of the industry. The diseases are highly contagious and the effects can be catastrophic. PEDv was first detected in the U.S in 2013. Within one year, it spread to 33 states and wiped out as many as 7 million pigs, or 10 percent of the nation's agricultural swine population.

Since then, U.S. producers have ramped up biosecurity measures, but PEDv remains endemic in the U.S. and new and emerging pests and diseases are on the rise. An ongoing outbreak of African swine fever in Asia has decimated pig herds across China, the world's largest consumer of pork, and pork prices are expected to hit record levels in 2019.

"Biosecurity efforts are often voluntary, but are critical to prevention, especially when there are no vaccines or treatments available," said Smith, principal investigator of UVM's animal disease biosecurity project. "We have to understand where people are on the risk continuum, their barriers and challenges, and their ability to act. That information is critical to the response."

ANAHEIM, CA (Embargoed until 9 a.m. PDT, Tuesday, June 25, 2019) - Acute kidney injury (AKI) often complicates the treatment outcomes of hospitalized patients, resulting in dangerous levels of toxic chemicals accumulating in the blood and causing numerous deaths annually. Currently, only supportive treatment is available for AKI, but two related research studies presented at the 2019 Annual Meeting of the Society of Nuclear Medicine and Molecular Imaging offer hope for effective treatment and prevention.

Reactive oxygen species (ROS), free radicals that trigger oxidative stress and inflammation, are believed to induce AKI. Both studies used mouse models to test new potential AKI therapies that target ROS.

The first study developed tiny nanoclusters with antioxidative properties that can pass through the kidneys' glomerular filtration barrier to treat AKI.

"In this study, ultra-small sized molybdenum-based polyoxometalate (POM) nanoclusters with preferential renal uptake were found to act as a novel type of nano-antioxidant to efficiently alleviate clinical symptoms of AKI mice," explains Dalong Ni, PhD, at the University of Wisconsin-Madison.

POM radiolabeled with zirconium-89 (89Zr) was intravenously injected into AKI mice. Longitudinal PET imaging was then performed at various time points to monitor the renal accumulation in vivo. The therapeutic value was evaluated by dynamic positron emission (PET) scans with gallium-68 (68Ga)-EDTA, blood urea nitrogen and creatinine measurements, H&E staining of kidney tissues, and biomarkers detection.

Ni reports, "The role of POM nanoclusters acting as antioxidants was confirmed both in vitro and in vivo, which was attributed to the readily variable valence state of molybdenum ions. Kidney transplantation and supportive therapies, such as rehydration and dialysis, are frequently required for patients with AKI. The protective effect of POM nanoclusters against AKI in living animals suggests exploring their use for the treatment of AKI patients."

He adds, "POM clusters could be synthesized in an easy, fast, and large-scale process, and they are mainly excreted through the kidneys (like most clinically-used imaging agents), making them highly biocompatible and reducing the potential toxic effects on patients."

The second study, also from the University of Wisconsin-Madison, uses extremely small nanomaterials as well. It demonstrates that selenium-doped carbon quantum dots can both treat and prevent AKI by localizing in the kidneys and eliminating ROS.

For the study, carbon quantum dots with high antioxidant capacity were prepared by doping selenium (SeCQDs) through a hydrothermal treatment. Molecular imaging provides the most effective method for investigating the biodistribution of nanomaterials, so PET imaging of SeCQDs was preformed to evaluate biodistribution using 89Zr after functionalizing with deferoxamine. Results of the SeCQDs treatment of the mice were compared with those from administration of an equivalent dose of amifostine, an FDA-approved drug for AKI therapy.

"The PET imaging results revealed that SeCQDs possess fascinating nano-bio interactions," explains Zachary Rosenkrans in the Pharmaceutical Sciences Department at the University of Wisconsin-Madison. "Surprisingly, we found that the administered dose almost entirely accumulated in the kidneys or was rapidly excreted in the urine, with little present in the liver or other organs. Results similar to this have rarely been reported."

The high accumulation of SeCQDs in the kidneys proved a highly effective therapy for the treatment of AKI that was induced using 50 percent glycerol, as well as prevention of AKI from cisplatin due to its antioxidant properties. In the same animal models, amifostine was unsuccessful in treating AKI.

Rosenkrans points out, "Due to this, we were able to demonstrate the advantages of utilizing nanomaterials compared to small molecules for renal disease treatment--in this case, AKI. This could most directly benefit the one in five hospitalized patients that experience AKI."

Excited about next steps, he adds, "This work could lead to guidelines to tailor nanoparticles to target and be retained in the kidneys, which has transformative potential to treat renal diseases. This may provide new avenues for more effective delivery of drugs to kidney cancer (or other kidney diseases, such as glomerulonephritis) and thus more efficacious therapies."

Both abstracts were presented at SNMMI's 66th Annual Meeting, June 22-25, Anaheim, CA.