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Ila Fiete studies how the brain performs complex computations




While doing a postdoc about 15 years ago, Ila Fiete began searching for faculty jobs in computational neuroscience — a field that uses mathematical tools to investigate brain function. However, there were no advertised positions in theoretical or computational neuroscience at that time in the United States.

“It wasn’t really a field,” she recalls. “That has changed completely, and [now] there are 15 to 20 openings advertised per year.” She ended up finding a position in the Center for Learning and Memory at the University of Texas at Austin, which along with a small handful of universities including MIT, was open to neurobiologists with a computational background.

Computation is the cornerstone of Fiete’s research at MIT’s McGovern Institute for Brain Research, where she has been a faculty member since 2018. Using computational and mathematical techniques, she studies how the brain encodes information in ways that enable cognitive tasks such as learning, memory, and reasoning about our surroundings.

One major research area in Fiete’s lab is how the brain is able to continuously compute the body’s position in space and make constant adjustments to that estimate as we move about. 

“When we walk through the world, we can close our eyes and still have a pretty good estimate of where we are,” she says. “This involves being able to update our estimate based on our sense of self-motion. There are also many computations in the brain that involve moving through abstract or mental rather than physical space, and integrating velocity signals of some variety or another. Some of the same ideas and even circuits for spatial navigation might be involved in navigating through these mental spaces.”

No better fit

Fiete spent her childhood between Mumbai, India, and the United States, where her mathematician father held a series of visiting or permanent appointments at the Institute for Advanced Study in Princeton, NJ, the University of California at Berkeley, and the University of Michigan at Ann Arbor.

In India, Fiete’s father did research at the Tata Institute of Fundamental Research, and she grew up spending time with many other children of academics. She was always interested in biology, but also enjoyed math, following in her father’s footsteps.

“My father was not a hands-on parent, wanting to teach me a lot of mathematics, or even asking me about how my math schoolwork was going, but the influence was definitely there. There’s a certain aesthetic to thinking mathematically, which I absorbed very indirectly,” she says. “My parents did not push me into academics, but I couldn’t help but be influenced by the environment.”

She spent her last two years of high school in Ann Arbor and then went to the University of Michigan, where she majored in math and physics. While there, she worked on undergraduate research projects, including two summer stints at Indiana University and the University of Virginia, which gave her firsthand experience in physics research. Those projects covered a range of topics, including proton radiation therapy, the magnetic properties of single crystal materials, and low-temperature physics.

“Those three experiences are what really made me sure that I wanted to go into academics,” Fiete says. “It definitely seemed like the path that I knew the best, and I think it also best suited my temperament. Even now, with more exposure to other fields, I cannot think of a better fit.”

Although she was still interested in biology, she took only one course in the subject in college, holding back because she did not know how to marry quantitative approaches with biological sciences. She began her graduate studies at Harvard University planning to study low-temperature physics, but while there, she decided to start explore quantitative classes in biology. One of those was a systems biology course taught by then-MIT professor Sebastian Seung, which transformed her career trajectory.

“It was truly inspiring,” she recalls. “Thinking mathematically about interacting systems in biology was really exciting. It was really my first introduction to systems biology, and it had me hooked immediately.”

She ended up doing most of her PhD research in Seung’s lab at MIT, where she studied how the brain uses incoming signals of the velocity of head movement to control eye position. For example, if we want to keep our gaze fixed on a particular location while our head is moving, the brain must continuously calculate and adjust the amount of tension needed in the muscles surrounding the eyes, to compensate for the movement of the head.

“Bizarre” cells

After earning her PhD, Fiete and her husband, a theoretical physicist, went to the Kavli Institute for Theoretical Physics at the University of California at Santa Barbara, where they each held fellowships for independent research. While there, Fiete began working on a research topic that she still studies today — grid cells. These cells, located in the entorhinal cortex of the brain, enable us to navigate our surroundings by helping the brain to create a neural representation of space.

Midway through her position there, she learned of a new discovery, that when a rat moves across an open room, a grid cell in its brain fires at many different locations arranged geometrically in a regular pattern of repeating triangles. Together, a population of grid cells forms a lattice of triangles representing the entire room. These cells have also been found in the brains of various other mammals, including humans.

“It’s amazing. It’s this very crystalline response,” Fiete says. “When I read about that, I fell out of my chair. At that point I knew this was something bizarre that would generate so many questions about development, function, and brain circuitry that could be studied computationally.”

One question Fiete and others have investigated is why the brain needs grid cells at all, since it also has so-called place cells that each fire in one specific location in the environment. A possible explanation that Fiete has explored is that grid cells of different scales, working together, can represent a vast number of possible positions in space and also multiple dimensions of space.

“If you have a few cells that can parsimoniously generate a very large coding space, then you can afford to not use most of that coding space,” she says. “You can afford to waste most of it, which means you can separate things out very well, in which case it becomes not so susceptible to noise.”

Since returning to MIT, she has also pursued a research theme related to what she explored in her PhD thesis — how the brain maintains neural representations of where the head is located in space. In a paper published last year, she uncovered that the brain generates a one-dimensional ring of neural activity that acts as a compass, allowing the brain to calculate the current direction of the head relative to the external world.

Her lab also studies cognitive flexibility — the brain’s ability to perform so many different types of cognitive tasks.

“How it is that we can repurpose the same circuits and flexibly use them to solve many different problems, and what are the neural codes that are amenable to that kind of reuse?” she says. “We’re also investigating the principles that allow the brain to hook multiple circuits together to solve new problems without a lot of reconfiguration.”



Electronic skin has a strong future stretching ahead




A material that mimics human skin in ?strength, stretchability and sensitivity could be used to collect biological data in real time. Electronic skin, or e-skin, may play an important role in next-generation prosthetics, personalized medicine, soft robotics and artificial intelligence.

“The ideal e-skin will mimic the many natural functions of human skin, such as sensing temperature and touch, accurately and in real time,” says KAUST postdoc Yichen Cai. However, making suitably flexible electronics that can perform such delicate tasks while also enduring the bumps and scrapes of everyday life is challenging, and each material involved must be carefully engineered.

Most e-skins are made by layering an active nanomaterial (the sensor) on a stretchy surface that attaches to human skin. However, the connection between these layers is often too weak, which reduces the durability and sensitivity of the material; alternatively, if it is too strong, flexibility becomes limited, making it more likely to crack and break the circuit.

“The landscape of skin electronics keeps shifting at a spectacular pace,” says Cai. “The emergence of 2D sensors has accelerated efforts to integrate these atomically thin, mechanically strong materials into functional, durable artificial skins.”

A team led by Cai and colleague Jie Shen has now created a durable e-skin using a hydrogel reinforced with silica nanoparticles as a strong and stretchy substrate and a 2D titanium carbide MXene as the sensing layer, bound together with highly conductive nanowires.

“Hydrogels are more than 70 percent water, making them very compatible with human skin tissues,” explains Shen. By prestretching the hydrogel in all directions, applying a layer of nanowires, and then carefully controlling its release, the researchers created conductive pathways to the sensor layer that remained intact even when the material was stretched to 28 times its original size.

Their prototype e-skin could sense objects from 20 centimeters away, respond to stimuli in less than one tenth of a second, and when used as a pressure sensor, could distinguish handwriting written upon it. It continued to work well after 5,000 deformations, recovering in about a quarter of a second each time. “It is a striking achievement for an e-skin to maintain toughness after repeated use,” says Shen, “which mimics the elasticity and rapid recovery of human skin.”

Such e-skins could monitor a range of biological information, such as changes in blood pressure, which can be detected from vibrations in the arteries to movements of large limbs and joints. This data can then be shared and stored on the cloud via Wi-Fi.

“One remaining obstacle to the widespread use of e-skins lies in scaling up of high-resolution sensors,” adds group leader Vincent Tung; “however, laser-assisted additive manufacturing offers new promise.”

“We envisage a future for this technology beyond biology,” adds Cai. “Stretchable sensor tape could one day monitor the structural health of inanimate objects, such as furniture and aircraft.”



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German researchers compile world’s largest inventory of known plant species




Leipzig could mean for the future of plant taxonomy what Greenwich meant for world time until 1972: it could become the reference city for correct scientific plant names. In an outstanding feat of research, the curator of the Botanical Garden of Leipzig University, Dr Martin Freiberg, and colleagues from iDiv and UL have compiled what is now the largest and most complete list of scientific names of all known plant species in the world. The Leipzig Catalogue of Vascular Plants (LCVP) enormously updates and expands existing knowledge on the naming of plant species, and could replace The Plant List (TPL) – a catalogue created by the Royal Botanic Gardens, Kew in London which until now has been the most important reference source for plant researchers.

“In my daily work at the Botanical Garden, I regularly come across species names that are not clear, where existing reference lists have gaps,” said Freiberg. “This always means additional research, which keeps you from doing your actual work and above all limits the reliability of research findings. I wanted to eliminate this obstacle as well as possible.”

World’s most comprehensive and reliable catalogue of plant names

With 1,315,562 scientific names, the LCVP is the largest of its kind in the world describing vascular plants. Freiberg compiled information from accessible relevant databases, harmonized it and standardised the names listed according to the best possible criteria. On the basis of 4500 other studies, he investigated further discrepancies such as different spellings and synonyms. He also added thousands of new species to the existing lists – species identified in recent years, mainly thanks to rapid advances in molecular genetic analysis techniques.

The LCVP now comprises 351,180 vascular plant species and 6160 natural hybrids across 13,460 genera, 564 families and 84 orders. It also lists all synonyms and provides further taxonomic details. This means that it contains over 70,000 more species and subspecies than the most important reference work to date, TPL. The latter has not been updated since 2013, making it an increasingly outdated tool for use in research, according to Freiberg.

“The catalogue will help considerably in ensuring that researchers all over the world refer to the same species when they use a name,” says Freiberg. Originally, he had intended his data set for internal use in Leipzig. “But then many colleagues from other botanical gardens in Germany urged me to make the work available to everyone.”

LCVP vastly expands global knowledge of plant diversity

“Almost every field in plant research depends on reliably naming species,” says Dr Marten Winter of iDiv, adding: “Modern science often means combining data sets from different sources. We need to know exactly which species people refer to, so as not to compare apples and oranges or to erroneously lump different species.” Using the LCVP as a reference will now offer researchers a much higher degree of certainty and reduce confusion. And this will also increase the reliability of research results, adds Winter.

“Working alone, Martin Freiberg has achieved something truly incredible here,” says the director of the Botanical Garden and co-author Prof Christian Wirth (UL, iDiv). “This work has been a mammoth task, and with the LCVP he has rendered an invaluable service to plant research worldwide. I am also pleased that our colleagues from iDiv, with their expertise in biodiversity informatics, were able to make a significant contribution to this work.”


This research was in part supported by the DFG – Deutsche Forschungsgemeinschaft (FZT-118).


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Benefits of Purchasing Used Lab Equipment




In the laboratory industry, there can be a lot of pressure to always have the newest and latest technology. Due to concerns about having outdated or inefficient equipment, many professionals don’t even consider purchasing used equipment. However, there are numerous advantages to doing so. Here are some of the key benefits of purchasing used lab equipment to keep in mind next time you need to purchase equipment.

Financial Benefits

One of the most significant and obvious benefits of purchasing used lab equipment is that doing so can save you a lot of money. Used laboratory equipment is significantly less expensive than brand new models. Often laboratories can save up to 50 percent or more by purchasing quality second-hand equipment.

Because laboratory equipment is often one of the top expenses that laboratories incur, purchasing used can substantially reduce laboratory costs and free up some much-needed room in tight budgets.


Environmental Benefits

Large laboratory equipment can take up a lot of room in landfills and often contain toxic components such as lead or mercury. Such toxins can seep into the earth and contaminate groundwater over time. By purchasing used laboratory equipment rather than new, you can reduce the amount of equipment that ends up in landfills. Plus, you will also reduce the number of raw materials used to manufacture new equipment which will decrease your lab’s negative impact on the environment.

Increased Insight

Purchasing a new type of equipment right after it is released comes with some risks. When a piece of equipment is fresh on the market, there aren’t many reviews from past customers attesting to how well or poorly it operates.\

Used equipment, however, is far less risky. Because the equipment has been on the market for a while, there are likely plenty of reviews that you can reference and any potential issues have likely been well-documented. Just make sure to purchase from a reliable and trustworthy reseller that took the proper measures to ensure the equipment is in optimal operating condition.

Reduced Wait Time

If you need a piece of equipment in a short period of time, buying used is often the best option. Many manufacturers have long wait times that can require you to wait for several weeks or even months before the equipment will arrive. If you have deadlines you need to meet, that simply won’t do. In cases when you need equipment in a timelier manner, used equipment is already built and ready to go so you often only have to wait for shipping.


Source: Christina Duron is a freelance writer for multiple online publications where she can showcase her affinity for all things digital. She has focused her career around digital marketing and writes to explore topics that spark her interest.


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An ionic forcefield for nanoparticles




Tunable coating allows hitch-hiking nanoparticles to slip past the immune system to their target

Nanoparticles are promising drug delivery tools, offering the ability to administer drugs directly to a specific part of the body and avoid the awful side effects so often seen with chemotherapeutics.

But there’s a problem. Nanoparticles struggle to get past the immune system’s first line of defense: proteins in the blood serum that tag potential invaders. Because of this, only about 1 percent of nanoparticles reach their intended target.

“No one escapes the wrath of the serum proteins,” said Eden Tanner, a former postdoctoral fellow in bioengineering at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS).

Now, Tanner and a team of researchers led by Samir Mitragotri, the Hiller Professor of Bioengineering and Hansjorg Wyss Professor of Biologically Inspired Engineering at SEAS, have developed an ionic forcefield that prevents proteins from binding to and tagging nanoparticles.

In mouse experiments, nanoparticles coated with the ionic liquid survived significantly longer in the body than uncoated particles and, surprisingly, 50 percent of the nanoparticles made it to the lungs. It’s the first time that ionic liquids have been used to protect nanoparticles in the blood stream.

“The fact that this coating allows the nanoparticles to slip past serum proteins and hitch a ride on red blood cells is really quite amazing because once you are able to fight the immune system effectively, lots of opportunities open up,” said Mitragotri, who is also a Core Faculty Member of Harvard’s Wyss Institute for Biologically Inspired Engineering

The research is published in Science Advances.

Ionic liquids, essentially liquid salts, are highly tunable materials that can hold a charge.

“We knew that serum proteins clear out nanoparticles in the bloodstream by attaching to the surface of the particle and we knew that certain ionic liquids can either stabilize or destabilize proteins,” said Tanner, who is now an Assistant Professor of Chemistry & Biochemistry at the University of Mississippi. “The question was, could we leverage the properties of ionic liquids to allow nanoparticles to slip past proteins unseen.”

“The great thing about ionic liquids is that every small change you make to their chemistry results in a big change in their properties,” said Christine Hamadani, a former graduate student at SEAS and first author of the paper. “By changing one carbon bond, you can change whether or not it attracts or repels proteins.”

Hamadani is currently a graduate student at Tanner’s lab at the University of Mississippi.

The researchers coated their nanoparticles with the ionic liquid choline hexenoate, which has an aversion to serum proteins. Once in the body, these ionic-liquid coated nanoparticles appeared to spontaneously attach to the surface of red-blood cells and circulate until they reached the dense capillary system of the lungs, where the particles sheared off into the lung tissue.

“This hitchhiking phenomenon was a really unexpected discovery,” said Mitragotri. “Previous methods of hitchhiking required special treatment for the nanoparticles to attach to red blood cells and even then, they only stayed at a target location for about six hours. Here, we showed 50 percent of the injected dose still in the lungs after 24 hours.”

The research team still needs to understand the exact mechanism that explains why these particles travel so well to lung tissue, but the research demonstrates just how precise the system can be.

“This is such a modular technology,” said Tanner, who plans to continue the research in her lab at University of Mississippi. “Any nanoparticle with a surface change can be coated with ionic liquids and there are millions of ionic liquids that can be tuned to have different properties. You could tune the nanoparticle and the liquid to target specific locations in the body.”

“We as a field need as many tools as we can to fight the immune system and get drugs where they need to go,” said Mitragotri. “Ionic liquids are the latest tool on that front.”


The research was co-authored by Morgan J. Goetz.


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