Fluid Systems Can Sometimes Serve As Analogs For Other Physical Phenomena. For Example, Bouncing Droplets

Actresses with passion in science

Sketching out magnetism with electricity

In a proof-of-concept study published in Nature Physics, researchers drew magnetic squares in a nonmagnetic material with an electrified pen and then “read” this magnetic doodle with X-rays.

The experiment demonstrated that magnetic properties can be created and annihilated in a nonmagnetic material with precise application of an electric field – something long sought by scientists looking for a better way to store and retrieve information on hard drives and other magnetic memory devices. The research took place at the Department of Energy’s SLAC National Accelerator Laboratory and the Korea Advanced Institute of Science and Technology.

“The important thing is that it’s reversible. Changing the voltage of the applied electric field demagnetizes the material again,” said Hendrik Ohldag, a co-author on the paper and scientist at the lab’s Stanford Synchrotron Radiation Lightsource (SSRL), a DOE Office of Science User Facility.

“That means this technique could be used to design new types of memory storage devices with additional layers of information that can be turned on and off with an electric field, rather than the magnetic fields used today,” Ohldag said. “This would allow more targeted control, and would be less likely to cause unwanted effects in surrounding magnetic areas.”

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winter sunrise reflections

by Denny Bitte

This car race involved years of training, feats of engineering, high-profile sponsorships, competitors from around the world and a racetrack made of gold.

But the high-octane competition, described as a cross between physics and motor-sports, is invisible to the naked eye. In fact, the track itself is only a fraction of the width of a human hair, and the cars themselves are each comprised of a single molecule.

The Nanocar Race, which happened over the weekend at Le centre national de la recherché scientific in Toulouse, France, was billed as the “first-ever race of molecule-cars.”

It’s meant to generate excitement about molecular machines. Research on the tiny structures won last year’s Nobel Prize in Chemistry, and they have been lauded as the “first steps into a new world,” as The Two-Way reported.

Microscopic Cars Square Off In Big Race

Image: CNRS

waaavess

New theory explains how beta waves arise in the brain

Beta rhythms, or waves of brain activity with an approximately 20 Hz frequency, accompany vital fundamental behaviors such as attention, sensation and motion and are associated with some disorders such as Parkinson’s disease. Scientists have debated how the spontaneous waves emerge, and they have not yet determined whether the waves are just a byproduct of activity, or play a causal role in brain functions. Now in a new paper led by Brown University neuroscientists, they have a specific new mechanistic explanation of beta waves to consider.

The new theory, presented in the Proceedings of the National Academy of Sciences, is the product of several lines of evidence: external brainwave readings from human subjects, sophisticated computational simulations and detailed electrical recordings from two mammalian model organisms.

“A first step to understanding beta’s causal role in behavior or pathology, and how to manipulate it for optimal function, is to understand where it comes from at the cellular and circuit level,” said corresponding author Stephanie Jones, research associate professor of neuroscience at Brown University. “Our study combined several techniques to address this question and proposed a novel mechanism for spontaneous neocortical beta. This discovery suggests several possible mechanisms through which beta may impact function.”

Making waves

The team started by using external magnetoencephalography (MEG) sensors to observe beta waves in the human somatosensory cortex, which processes sense of touch, and the inferior frontal cortex, which is associated with higher cognition.

They closely analyzed the beta waves, finding they lasted at most a mere 150 milliseconds and had a characteristic wave shape, featuring a large, steep valley in the middle of the wave.

The question from there was what neural activity in the cortex could produce such waves. The team attempted to recreate the waves using a computer model of a cortical circuitry, made up of a multilayered cortical column that contained multiple cell types across different layers. Importantly, the model was designed to include a cell type called pyramidal neurons, whose activity is thought to dominate the human MEG recordings.

They found that they could closely replicate the shape of the beta waves in the model by delivering two kinds of excitatory synaptic stimulation to distinct layers in the cortical columns of cells: one that was weak and broad in duration to the lower layers, contacting spiny dendrites on the pyramidal neurons close to the cell body; and another that was stronger and briefer, lasting 50 milliseconds (i.e., one beta period), to the upper layers, contacting dendrites farther away from the cell body. The strong distal drive created the valley in the waveform that determined the beta frequency.

Meanwhile they tried to model other hypotheses about how beta waves emerge, but found those unsuccessful.

With a model of what to look for, the team then tested it by looking for a real biological correlate of it in two animal models. The team analyzed measurements in the cortex of mice and rhesus macaques and found direct confirmation that this kind of stimulation and response occurred across the cortical layers in the animal models.

“The ultimate test of the model predictions is to record the electrical signals inside the brain,” Jones said. “These recordings supported our model predictions.”

Beta in the brain

Neither the computer models nor the measurements traced the source of the excitatory synaptic stimulations that drive the pyramidal neurons to produce the beta waves, but Jones and her co-authors posit that they likely come from the thalamus, deeper in the brain. Projections from the thalamus happen to be in exactly the right places needed to deliver signals to the right positions on the dendrites of pyramidal neurons in the cortex. The thalamus is also known to send out bursts of activity that last 50 milliseconds, as predicted by their theory.

With a new biophysical theory of how the waves emerge, the researchers hope the field can now investigate whether beta rhythms affect or merely reflect behavior and disease. Jones’s team in collaboration with Professor of Neuroscience Christopher Moore at Brown is now testing predictions from the theory that beta may decrease sensory or motor information processing functions in the brain. New hypotheses are that the inputs that create beta may also stimulate inhibitory neurons in the top layers of the cortex, or that they may may saturate the activity of the pyramidal neurons, thereby reducing their ability to process information; or that the thalamic bursts that give rise to beta occupy the thalamus to the point where it doesn’t pass information along to the cortex.

Figuring this out could lead to new therapies based on manipulating beta, Jones said.

“An active and growing field of neuroscience research is trying to manipulate brain rhythms for optimal function with stimulation techniques,” she said. “We hope that our novel finding on the neural origin of beta will help guide research to manipulate beta, and possibly other rhythms, for improved function in sensorimotor pathologies.”

“I came to America when I was six years old. Mom said she brought us here so that we’d have opportunities in life. She said that back in the Bahamas, it’s only the ‘haves’ and the ‘have nots.’ She wanted us to have more choices. But I don’t think she fully understood how things work here. She was a news reporter back in the Bahamas. But the only job she could get here was taking care of oldpeople. My dad could only work construction. We moved to four different states just so they could find work. They always told me, ‘Just study hard in school and everything will work out fine.’ So that was my plan. I got all A’s up until the 11th grade– except for one B in math. My goal was to get top twenty in my class, then go to college, then get a degree, and then get a job. I realized the truth my senior year. My guidance counselor told me I couldn’t get a loan. I couldn’t get financial aid. Even if I could find a way to pay for school, I probably couldn’t get a job. I felt so mad at everyone. There were some kids who completely slacked off in school, but even they were going to college. I started having panic attacks. My dad told me not to worry. He called me a ‘doubting Peter.’ He invited all his friends over to a fish fry to help raise money. And he did get $3,000. But that wasn’t enough. So I searched really hard on the Internet and found the Dream.us scholarship. My mom was so excited when I got it. They’re paying for me to go to Queens College. Now my mom’s really scared again because DACA got revoked. She’s crying all the time at work. I try to tell her that no matter what happens, we’re not going to die. We just might have to start over.”