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Fast calculation dials in better batteries

A simpler and more efficient way to predict performance will lead to better batteries, according to Rice University engineers.

That their method is 100,000 times faster than current modeling techniques is a nice bonus.

The analytical model developed by materials scientist Ming Tang and graduate student Fan Wang of Rice University’s Brown School of Engineering doesn’t require complex numerical simulation to guide the selection and design of battery components and how they interact.

The simplified model developed at Rice — freely accessible online — does the heavy lifting with an accuracy within 10% of more computationally intensive algorithms. Tang said it will allow researchers to quickly evaluate the rate capability of batteries that power the planet.

The results appear in the open-access journal Cell Reports Physical Science.

There was a clear need for the updated model, Tang said.

“Almost everyone who designs and optimizes battery cells uses a well-established approach called P2D (for pseudo-two dimensional) simulations, which are expensive to run,” Tang said. “This especially becomes a problem if you want to optimize battery cells, because they have many variables and parameters that need to be carefully tuned to maximize the performance.

“What motivated this work is our realization that we need a faster, more transparent tool to accelerate the design process, and offer simple, clear insights that are not always easy to obtain from numerical simulations,” he said.

Battery optimization generally involves what the paper calls a “perpetual trade-off” between energy (the amount it can store) and power density (the rate of its release), all of which depends on the materials, their configurations and such internal structures as porosity.

“There are quite a few adjustable parameters associated with the structure that you need to optimize,” Tang said. “Typically, you need to make tens of thousands of calculations and sometimes more to search the parameter space and find the best combination. It’s not impossible, but it takes a really long time.”

He said the Rice model could be easily implemented in such common software as MATLAB and Excel, and even on calculators.

To test the model, the researchers let it search for the optimal porosity and thickness of an electrode in common full- and half-cell batteries. In the process, they discovered that electrodes with “uniform reaction” behavior such as nickel-manganese-cobalt and nickel-cobalt-aluminum oxide are best for applications that require thick electrodes to increase the energy density.

They also found that battery half-cells (with only one electrode) have inherently better rate capability, meaning their performance is not a reliable indicator of how electrodes will perform in the full cells used in commercial batteries.

The study is related to the Tang lab’s attempts at understanding and optimizing the relationship between microstructure and performance of battery electrodes, the topic of several recent papers that showed how defects in cathodes can speed lithium absorption and how lithium cells can be pushed too far in the quest for speed.

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Brain’s immune cells promising cellular target for therapeutics

Inspired by the need for new and better therapies for neurodegenerative diseases, such as Parkinson’s disease and Alzheimer’s disease, Rutgers University researchers are exploring the link between uncontrolled inflammation within the brain and the brain’s immune cells, known as microglia.

Most therapies for brain health disorders focus on the major cells of the nervous system: neurons. But microglia cells are emerging as a promising cellular target because of the prominent role they play in brain inflammation. In addition, microglial behavior can be engineered to rein in inflammation, which is caused by different factors, and the damage it causes.

In APL Bioengineering, from AIP Publishing, the group highlights the design considerations and benefits of creating therapeutic nanoparticles for carrying pharmacological factors directly to the sites of the microglia.

Microglia are essentially first responders to pathological changes within the brain and can readily clear out undesired and foreign substances.

“Emerging drugs and biological factors can be targeted and released in controlled ways within the brain if their nanoscale carriers can be engineered,” said Prabhas V. Moghe, co-author on the paper. “We believe this field is ripe for technological, biological, and clinical breakthroughs.”

The group’s ultimate goal is to tamp down the uncontrolled activation of microglial inflammation.

“Within our lab at Rutgers, we are developing a new therapeutic strategy targeted to the microglia activated by the excessive deposition of the protein alpha-synuclein,” Moghe said. “This will potentially address a major therapeutic barrier of microglial activation in neurodegenerative diseases.”

Targeting microglia in this manner may open up avenues for the development of novel therapeutics.

“Studying nanoparticle interactions with microglia can guide the design of successful nanomedicine platforms that enable targeted delivery of drugs while minimizing off-target effects and system-level toxicity,” Moghe said. “Considering the complex nature of neurodegenerative disorders, rather than solely focusing on therapies for neurons, it may be worth directing therapeutics to the mediator, microglia, whose functional restoration will protect neurons.”

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Linking sight and movement

To get a better look at the world around them, animals constantly are in motion. Primates and people use complex eye movements to focus their vision (as humans do when reading, for instance); birds, insects, and rodents do the same by moving their heads, and can even estimate distances that way. Yet how these movements play out in the elaborate circuitry of neurons that the brain uses to “see” is largely unknown. And it could be a potential problem area as scientists create artificial neural networks that mimic how vision works in self-driving cars.

To better understand the relationship between movement and vision, a team of Harvard researchers looked at what happens in one of the brain’s primary regions for analyzing imagery when animals are free to roam naturally. The results of the study, published Tuesday in the journal Neuron, suggest that image-processing circuits in the primary visual cortex not only are more active when animals move, but that they receive signals from a movement-controlling region of the brain that is independent from the region that processes what the animal is looking at. In fact, the researchers describe two sets of movement-related patterns in the visual cortex that are based on head motion and whether an animal is in the light or the dark.

The movement-related findings were unexpected, since vision tends to be thought of as a feed-forward computation system in which visual information enters through the retina and travels on neural circuits that operate on a one-way path, processing the information piece by piece. What the researchers saw here is more evidence that the visual system has many more feedback components where information can travel in opposite directions than had been thought.

These results offer a nuanced glimpse into how neural activity works in a sensory region of the brain, and add to a growing body of research that is rewriting the textbook model of vision in the brain.

“It was really surprising to see this type of [movement-related] information in the visual cortex because traditionally people have thought of the visual cortex as something that only processes images,” said Grigori Guitchounts, a postdoctoral researcher in the Neurobiology Department at Harvard Medical School and the study’s lead author. “It was mysterious, at first, why this sensory region would have this representation of the specific types of movements the animal was making.”

While the scientists weren’t able to definitively say why this happens, they believe it has to do with how the brain perceives what’s around it.

“The model explanation for this is that the brain somehow needs to coordinate perception and action,” Guitchounts said. “You need to know when a sensory input is caused by your own action as opposed to when it’s caused by something out there in the world.”

For the study, Guitchounts teamed up with former Department of Molecular and Cellular Biology Professor David Cox, alumnus Javier Masis, M.A. ’15, Ph.D. ’18, and postdoctoral researcher Steffen B.E. Wolff. The work started in 2017 and wrapped up in 2019 while Guitchounts was a graduate researcher in Cox’s lab. A preprint version of the paper published in January.

The typical setup of past experiments on vision worked like this: Animals, like mice or monkeys, were sedated, restrained so their heads were in fixed positions, and then given visual stimuli, like photographs, so researchers could see which neurons in the brain reacted. The approach was pioneered by Harvard scientists David H. Hubel and Torsten N. Wiesel in the 1960s, and in 1981 they won a Nobel Prize in medicine for their efforts. Many experiments since then have followed their model, but it did not illuminate how movement affects the neurons that analyze.

Researchers in this latest experiment wanted to explore that, so they watched 10 rats going about their days and nights. The scientists placed each rat in an enclosure, which doubled as its home, and continuously recorded their head movements. Using implanted electrodes, they measured the brain activity in the primary visual cortex as the rats moved.

Half of the recordings were taken with the lights on. The other half were recorded in total darkness. The researchers wanted to compare what the visual cortex was doing when there was visual input versus when there wasn’t. To be sure the room was pitch black, they taped shut any crevice that could let in light, since rats have notoriously good vision at night.

The data showed that on average, neurons in the rats’ visual cortices were more active when the animals moved than when they rested, even in the dark. That caught the researchers off guard: In a pitch-black room, there is no visual data to process. This meant that the activity was coming from the motor cortex, not an external image.

The team also noticed that the neural patterns in the visual cortex that were firing during movement differed in the dark and light, meaning they weren’t directly connected. Some neurons that were ready to activate in the dark were in a kind of sleep mode in the light.

Using a machine-learning algorithm, the researchers encoded both patterns. That let them not only tell which way a rat was moving its head by just looking at the neural activity in its visual cortex, but also predict the movement several hundred milliseconds before the rat made it.

The researchers confirmed that the movement signals came from the motor area of the brain by focusing on the secondary motor cortex. They surgically destroyed it in several rats, then ran the experiments again. The rats in which this area of the brain was lesioned no longer gave off signals in the visual cortex. However, the researchers were not able to determine if the signal originates in the secondary motor cortex. It could be only where it passes through, they said.

Furthermore, the scientists pointed out some limitations in their findings. For instance, they only measured the movement of the head, and did not measure eye movement. The study is also based on rodents, which are nocturnal. Their visual systems share similarities with humans and primates, but differ in complexity. Still, the paper adds to new lines of research and the findings could potentially be applied to neural networks that control machine vision, like those in autonomous vehicles.

“It’s all to better understand how vision actually works,” Guitchounts said. “Neuroscience is entering into a new era where we understand that perception and action are intertwined loops. … There’s no action without perception and no perception without action. We have the technology now to measure this.”

This work was supported by the Harvard Center for Nanoscale Systems and the National Science Foundation Graduate Research Fellowship.

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ProgrammableWeb

PartnerMatrix Adds API for Casino and Betting Websites

PartnerMatrix introduces new API development which helps casino and betting websites to have a better understanding of their affiliate marketing programs. The real-time data API feature allows Affiliate Managers to track users’ actions in real-time, without delay or inaccuracy, view instant reports and access full users’ history and flow.

PartnerMatrix’s API based solution provides transparent and instant data both for operators and affiliates, helps build trustworthy relationships, discourages possible frauds, and improves the day-to-day operations. The first client to leverage the new feature is Prisma Gaming, which is set to integrate it across its B2C brands and clients.

The API integration gives gaming operators a better understanding of the results of their campaigns. The real-time data supplies a wealth of information which helps Affiliate Managers in making well-informed decisions about their ongoing promotional activities. Operators can quickly decide if they should continue promotion, invest more in a campaign, or end it if the results aren’t rising to the expectations.

Levon Nikoghosyan, PartnerMatrix CEO, comments: “Currently, affiliate software providers offer reports via FTP integrations on both operator and affiliate side. However, it can take up to one day to receive the data results. PartnerMatrix’s API integration allows instant reporting, which can lead to more transparency, trust and cooperation between iGaming affiliates and operators.”

Part of EveryMatrix Group, PartnerMatrix was created under the vision of one system to reach millions of players, currently catering to over 100 casino and betting operators, including Dafabet, Nextbet, Gigapotti, MaxBet, ShangriLa or TotoGaming, with 24 new clients joining in the last 12 months.

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Double bubbles pierce with less trouble

Two microscopic bubbles are better than one at penetrating soft materials, concludes a new study by engineers at the University of California, Riverside.

Optical cavitation, which uses a laser to form bubbles in a liquid that expand rapidly then collapse, could be a safe way to quickly and efficiently deliver therapeutic agents, such as drugs or genes, directly into living cells. Current methods for introducing foreign materials into cells, known as transfection, rely on puncturing the outer membrane with a laser, which risks heat damage to the cell, or a pipette, which risks contamination.

Though not quite ready for prime time yet, scientists are improving optical cavitation techniques. The new paper shows two bubbles produce long, fine jets that penetrate far enough with only five pulses to make cavitation potentially suitable for transfection or needle-free injections.

“The study of cavitation bubbles has evolved relatively fast, from learning how to avoid the damage they cause on ship propellers to benefitting medicine delivery,” said Vicente Robles, a doctoral student at the Marlan and Rosemary Bourns College of Engineering, who led the study. “The biggest limitation on their applications is our creativity.”

Cavitation bubbles are micron-sized and live for only a fraction of a second, but generate strong, local changes in physical properties of the surrounding medium, making them prime candidates for localized surface cleaning, cell targeting, and heating or cooling.

In double-bubble configurations, one bubble collapses faster and accelerates the neighboring bubble to invert and pierce itself, emitting a fast jet that could, if forceful enough, also pierce a cell membrane and possibly be used to transfect a cell. However, the jet’s speed, force, and trajectory are highly influenced by the mechanical properties of the medium surrounding it and the spatial and temporal separations of the bubbles.

Robles started by using lasers to create bubbles that form jets of water directed at a medium. He then compared single- and double-bubble jets directed at both petroleum jelly and a transparent agar gel widely used to model human tissue.

The double-bubble process created elongated, fast, focused jets that increased in length and volume when directed at the agar gel. Just five pulses penetrated 1.5 millimeters — enough to pierce human skin. This was achieved without the special micro-nozzles used in existing laser injection systems. In petroleum jelly, double-bubble jetting produced the same penetration length as single-bubble jetting, but with a 45% reduction in damage area, potentially resulting in less thermal and shockwave damage to the surrounding medium, and from three times farther away.

“The use of a laser-induced double-bubble arrangement is a significant advantage over previous studies, which rely on a converging nozzle or pressurized cavity to produce forceful jets,” mechanical engineering professor and senior author Guillermo Aguilar said. “Here, we take advantage of the inherent physics of the asynchronous collapse of two bubbles to accelerate the jet that pierces the nearby surface.”

The study concludes double-bubble cavitation could offer compact, device-free alternatives for needle-free applications after further study and improvement.

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New opportunity to develop high-energy batteries

In recent years, lithium-ion batteries have become better at supplying energy to Soldiers in the field, but the current generation of batteries never reaches its highest energy potential. Army researchers are extremely focused on solving this challenge and providing the power Soldiers demand.

At the U.S. Army Combat Capabilities Development Command’s Army Research Laboratory, in collaboration with the University of Maryland, scientists may have found a solution.

“We are very excited to demonstrate a new electrolyte design for lithium ion batteries that improves anode capacity by more than five times compared to traditional methods,” said Army scientist Dr. Oleg Borodin. “This is the next step needed to move this technology closer to commercialization.”

The team designed a self-healing, protective layer in the battery that significantly slows down the electrolyte and silicon anode degradation process, which could extend the lifespan of next generation lithium-ion batteries.

Their latest battery design increased the number of possible cycles from tens to over a hundred with little degradation. The journal Nature Energy published their findings.

Here’s how a battery works. A battery stores chemical energy and converts it into electrical energy. Batteries have three parts, an anode (-), a cathode (+), and the electrolyte. An anode is an electrode through which the conventional current enters into a polarized electrical device. This contrasts with a cathode, through which current leaves an electrical device.

The electrolyte keeps the electrons from going straight from the anode to the cathode within the battery. In order to create better batteries, Borodin said, you can increase the capacity of the anode and the cathode, but the electrolyte has to be compatible between them.

Lithium-ion batteries generally use graphite anodes, which have a capacity of about 370 milliamp hours (mAh) per gram. But anodes made out of silicon can offer about 1,500 to 2,800 mAh per gram, or at least four times as much capacity.

The researchers said silicon particle anodes, as opposed to traditional graphite anodes, provide excellent alternatives, but they also degrade much faster. Unlike graphite, silicon expands and contracts during a battery’s operation. As the silicon nanoparticles within the anode get larger, they often crack the protective layer — called the solid electrolyte interphase — that surrounds the anode.

The solid electrolyte interphase forms naturally when anode particles make direct contact with the electrolyte. The resulting barrier prevents further reactions from occurring and separates the anode from the electrolyte. But when this protective layer becomes damaged, the newly exposed anode particles will react continuously with electrolyte until it runs out.

“Others have tried to tackle this problem by designing a protective layer that expands when the silicon anode does,” Borodin said. “However, these methods still cause some electrolyte degradation, which significantly shortens the lifetime of the anode and the battery.”

The joint team at the University of Maryland and the Army Research Laboratory decided to try a new approach. Instead of an elastic barrier, the researchers designed a rigid barrier that doesn’t break apart — even when the silicon nanoparticles expand. They developed a lithium-ion battery with an electrolyte that formed a rigid Lithium Fluoride solid electrolyte interphase, or SEI, when electrolyte interacts with the silicon anode particles and substantially reduced electrolyte degradation.

“We successfully avoided the SEI damage by forming a ceramic SEI that has a low affinity to the lithiated silicon particles, so that the lithiated silicon can relocate at the interface during volume change without damaging the SEI,” said Prof. Chunsheng Wang, a professor of Chemical and Biomolecular Engineering at the University of Maryland. “The electrolyte design principle is universal for all alloy anodes and opens a new opportunity to develop high-energy batteries.”

The battery design that Borodin and Wang’s group conceived demonstrated a coulombic [the basic unit of electric charge] efficiency of 99.9 percent, which meant that only 0.1 percent of the energy was lost to electrolyte degradation each cycle.

This is a significant improvement over conventional designs for lithium-ion batteries with silicon anodes, which have a 99.5-percent efficiency. While seemingly small, Borodin said this difference translates to a cycle life more than five times longer.

“Experiments performed by Dr. Chunsheng Wang’s group at the University of Maryland showed that this new method was successful,” Borodin said. “However, it was successful not only for silicon but also for aluminum and bismuth anodes, which shows the universality of the principle.”

The new design also came with several other benefits. The battery’s higher capacity allowed the electrode to be markedly thinner, which made the charging time much faster and battery itself much lighter. In addition, the researchers found that the battery could handle colder temperatures better than normal batteries.

“For regular batteries, colder temperatures slow diffusion and may even freeze the liquids inside the batteries,” Borodin said. “But because our design has a much higher capacity, thus ions have to diffuse shorter distances, resulting in a significantly improved low temperature operation, which is important for warfighters operating in cold climates.”

The team thanked the ARL Enterprise for Multiscale Modeling of Materials program for its support during the research effort so far.

According to Borodin, the next step in the research is to develop a larger cell with a higher voltage using this design. In light of this goal, the team is currently looking into advancements into the cathode side of the lithium-ion battery.

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Lipid gradient that keeps your eyes wet

New understandings of how lipids function within tears could lead to better drugs for treating dry eye disease.

A new approach has given Hokkaido University researchers insight into the synthesis and functions of lipids found in tears. Their findings, published in the journal eLife, could help the search for new treatments for dry eye disease.

The film of tears covering the eye’s surface is vital for eliminating foreign objects, providing oxygen and nutrients to the eye’s outer tissues, and reducing friction with the eyelid. The film is formed of an outer lipid layer and an inner liquid layer. The outer lipid layer, which is itself formed of two sublayers, prevents water evaporation from the liquid layer. Dry eye disease develops when the glands that produce these lipids dysfunction. However, it has remained unclear how those generally incompatible layers — water and lipid — can form and maintain tear films.

Hokkaido University biochemist Akio Kihara and colleagues wanted to understand the functions of a subclass of lipids called OAHFAs (O-Acyl)-ω-hydroxy fatty acids) that are present in the inner lipid sublayer (amphiphilic lipid sublayer) just above the liquid layer of the tear film. OAHFAs are known to have both polar and non-polar ends in its molecule, giving them affinity for both water and lipid.

To do this, they turned off a gene called Cyp4f39 in mice that is known for its involvement in ω-hydroxy fatty acid synthesis. Previous attempts at studying the gene’s functions in this way had led to neonatal death in mice, as it impaired the skin’s protective role. The team used a way to turn the gene off, except in the skin.

The mice were found to have damaged corneas and unstable tear films, both indicative of dry eyes. Further analyses showed that these mice were lacking OAHFAs and their derivatives in their tear films. Interestingly, the scientists also discovered that the OAHFA derivatives have polarities intermediate between OAHFAs and other lipids in the tear film. This strongly suggests that those lipids together form a polarity gradient that plays an important role in connecting the tear film’s inner liquid layer and outer lipid layer, helping the film spread uniformly over the surface of the eye.

“Drugs currently used in dry eye disease target the liquid layer of the tear film, but there aren’t any drugs that target its lipid layer,” says Akio Kihara. “Since most cases of dry eye disease are caused by abnormalities in the lipid layer, eye drops containing OAHFAs and their derivatives could be an effective treatment.”

Further studies are required to fully understand the functions and synthesis of OAHFAs.

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IEEE VR Conference – Now Streaming!

There’s no better time to explore a conference about VR… *in VR!* Watch the IEEE Virtual Reality Conf now on Twitch or Mozilla Hubs. Plus, hear what Alex learned from Hakim Si-Mohammed’s talk about using brainwave tech for error detection in virtual reality!

// http://ieeevr.org/2020/
// https://www.facebook.com/ieeevr
// https://twitter.com/IEEEVR
// https://twitter.com/hashtag/IEEEVR2020
// https://twitter.com/glowascii/status/1242880318006153218

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Video game experience, gender may improve VR learning

Students who used immersive virtual reality (VR) did not learn significantly better than those who used two more traditional forms of learning, but they vastly preferred the VR to computer-simulated and hands-on methods, a new Cornell study has found.

“We didn’t know exactly what we were going to see,” said Jack Madden, doctoral student in astronomy at Cornell University and first author of “Ready Student One: Exploring the Predictors of Student Learning in Virtual Reality,” which published March 25 in PLOS ONE. “But it’s amazing that this brand-new technology performed just as well as these tried-and-true methods that are used today in classrooms. So at least we’re not harming students by using VR.”

Though the virtual reality experiment didn’t change learning outcomes overall, the researchers found that students with more video game experience learned better using VR than those with little video game experience — a finding that correlated closely with gender.

The study — which has new implications as learning around the world shifts online to combat the spread of coronavirus — aimed to take a step toward determining whether new educational technology tactics, while popular, are actually effective.

“There’s been a big push for enhanced technology in classrooms,” Madden said. “I think we can be in awe of these fancy, shiny devices and it might feel like they’re helping, but we need to know if they actually are.”

Males were far more likely to have video game experience, the survey found, and also learned more in the VR simulation, suggesting that either gender or prior video game experience could impact the success of VR-based learning. Reviewing prior work, the researchers found that video games requiring players to navigate 3D spaces are more popular among males than females.

“This is an interesting finding, because it could potentially imply that if you can provide learners with that experience, then you could show broad benefits from immersive learning,” said co-author Andrea Stevenson Won, assistant professor of communication and director of the Virtual Embodiment Lab at Cornell. “However, more study is definitely needed.”

“If you’re unfamiliar with navigating this kind of 3D space, you’re not going to learn as well in it, so that could be a barrier,” Madden said. “One of the conclusions of our work is that we need to do a better job of asking questions around things that might be gendered, like video game experience. There’s a lot of finer detail you need to know to make VR learning successful.”

The study’s co-authors are Natasha Holmes, the Ann S. Bower Assistant Professor in A&S; Jonathon Schuldt, associate professor of communication; and communication doctoral students Swati Pandita and Byungdoo Kim. The research was supported by Oculus Education.

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US HHS Introduces New Healthcare APIs

The US Department of Health and Human Services (HHS) has finalized two rules aimed at delivering US patients better access to their own health data. One rule was issued by the HHS Office of National Coordinator for Health Information Technology (ONC). The other was issued by HHS Centers for Medicare & Medicaid Services (CMS).

The ONC rule establishes new rules around “information blocking” practices that have historically plagued the free flow of data in the healthcare space. This ONC rule establishes a standards-based API, data classes and elements, and new business models of care that will allow patients to access their data from healthcare providers in the patients’ apps of choice. For more information, visit the ONC rule.

The CMS rule focuses on data interoperability. To fulfill its goal, the CMS rule creates the Patient Access API. Through the API, patients will gain access to data through third-party apps, and that data will be complete (including everything needed to avoid redundant tests when switching to a new healthcare provider). For more information, visit the CMS rule.

These rules do not come into immediate effect. The ONC rule will undergo a two-year phase-in period. The CMS rule will be partially in effect as of January 1, 2021, To read more, and for links to specific details, visit the HHS announcement.

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