“Our research on rats with heart failure shows that exercise reduces the severity of the disease, improves heart function and increases work capacity. And the intensity of the training is really importance to achieve this effect,” says Thomas Stølen, a researcher at the Norwegian University of Science and Technology (NTNU).

Stølen and his colleague Morten Høydal are the main authors of a comprehensive study published in the Journal of Molecular and Cellular Cardiology. The researchers went to great lengths to investigate what happens inside tiny heart muscle cells after regular exercise.

“We found that exercise improves important properties both in the way heart muscle cells handle calcium and in conducting electrical signals in the heart. These improvements enable the heart to beat more vigorously and can counteract life-threatening heart rhythm disorders,” says Stølen.

For a heart to be able to beat powerfully, regularly and synchronously, a lot of functions have to work together. Each time the heart beats, the sinus node — the heart’s own pacemaker — sends out electrical impulses to the rest of the heart. These electrical impulses are called action potentials.

All the heart muscle cells are enclosed by a membrane. At rest, the electrical voltage on the inside of the cell membrane is negative compared to the voltage on the outside. The difference between the voltage on the outside and the inside of the cell membrane is called the resting membrane potential.

When the action potentials reach the heart muscle cells, they need to overcome the resting membrane potential of each cell to depolarize the cell wall. When this happens, calcium can flow into the cell through channels in the cell membrane.

Calcium initiates the actual contraction of the heart muscle cells. When this process is complete, calcium is transported out of the cell or back to its storage site inside each heart muscle cell. From there, the calcium is ready to contribute to a new contraction the next time an action potential comes rushing by.

If the heart’s electrical conduction or calcium management system fails, the risk is that fewer heart muscle cells will contract, the contraction in each cell will be weak, and the electrical signals will become chaotic so that the heart chambers begin to flutter.

“All these processes are dysfunctional when someone has heart failure. The action potentials last too long, the resting potential of the cells is too high, and the transport function of the calcium channels in the cell wall is disturbed. Calcium then constantly leaks from its storage places inside every heart muscle cell,” Stølen says.

Before Stølen gives us the rest of the good news, he notes, “Our results show that intensive training can completely or partially reverse all these dysfunctions.”

Normally, the sinus node causes a human heart to beat between 50 and 80 beats every minute when at rest. This is enough to supply all the organ systems and cells in the body with as much oxygen-rich blood as they need to function properly.

When we get up to take a walk, our heart automatically starts beating a little faster and pumping a little harder so that the blood supply is adapted to the increased level of activity. The higher the intensity of the activity, the harder the heart has to work.

Exercise strengthens the heart so it can pump more blood out to the rest of the body with each beat. Thus, the sinus node can take it a little easier, and well-trained people have a lower resting heart rate than people who have not done regular endurance training.

At the other end of the continuum are people with heart failure. Here the pumping capacity of the heart is so weak that the organs no longer receive enough blood to maintain good functioning. People with heart failure have a low tolerance for exercise and often get out of breath with minimal effort.

In other words, increasing the pumping power to the heart is absolutely crucial for the quality of life and health of people with heart failure.

Many of the more than 100,000 Norwegians who live with heart failure have developed the condition after suffering a major heart attack — just like the rats in Stølen and Høydal’s study.

In the healthy rats, the heart pumped 75 percent of the blood with each contraction. In rats with heart failure, this measure of pump capacity, called ejection fraction, was reduced to 20 per cent, Stølen says.

The ejection fraction increased to 35 percent after six to eight weeks with almost daily interval training sessions on a treadmill. The rats did four-minute intervals at about 90 percent of their maximum capacity, quite similar to the 4 × 4 method that has been advocated by several research groups at NTNU for many years.

“The interval training also significantly improved the rats’ conditioning. After the training period, their fitness level was actually better than that of the untrained rats that hadn’t had a heart attack,” says Stølen.

Impaired calcium handling in a heart muscle cell not only causes the cell to contract with reduced force every time there is an action potential. It also causes the calcium to accumulate inside the fluid-filled area of the cell — the cytosol — where each contraction begins.

The calcium stores inside the cells are only supposed to release calcium when the heart is preparing to beat. Heart failure, however, causes a constant leakage of calcium out of these stores. After each contraction, calcium needs to be efficiently transported back into the calcium stores — or out of the heart muscle cell — via specialized pumps. In heart failure patients, these pumps work poorly.

When a lot of calcium builds up inside the cytosol, the heart muscle cells can initiate new contractions when they’re actually supposed to be at rest. An electrical gradient develops which causes the heart to send electrical signals when it shouldn’t. This can cause fibrillation in the heart chambers. This ventricular fibrillation is fatal and a common cause of cardiac arrest.

“We found that interval training improves a number of mechanisms that allow calcium to be pumped out of the cells and stored more efficiently inside the cells. The leakage from the calcium stores inside the cells also stopped in the interval-trained rats,” says Stølen.

The effect was clear when the researchers tried to induce ventricular fibrillation in the diseased rat hearts: they only succeeded at this in one of nine animals that had completed interval training. By comparison, they had no problems inducing fibrillation in all the rats with heart failure who had not exercised.

So far, the research group had shown that exercise improves calcium management in diseased heart muscle cells in several ways. The training also makes the electrical wiring system of the heart more functional.

In addition, they showed that exercise counteracted processes that cause the heart to become big and stiff.

Taken together, these improvements make each heartbeat more powerful and reduce the severity of heart failure. The risk of dangerous ventricular fibrillation was also reduced.

But Stølen and team still lacked an answer to why exercise corrects slow action potentials and ensures that the heart muscle cells are able to take care of calcium in the right way.

Therefore, they investigated whether the training had altered the genetic activity inside the rat cells. Thousands of different types of micromolecules called micro-RNA probably control most of this activity through direct interaction with genes.

“It turned out that 55 of the micro-RNA variants we examined were altered in rats with heart failure compared to the healthy rats. Interval training changed 18 of these back towards healthy levels. Several of the relevant micromolecules are known to play a role in both calcium management and the electrical conduction system of the heart, but the most interesting thing is that we discovered new micro-RNAs that can play an important role in heart failure,” says Stølen.

This article has mostly considered the effects of high-intensity interval training. But the study also includes a group of rats that trained more sedately.

The rats in this group ran the same distance and thus did as much total training work as the rats in the interval training group. However, they had to exercise longer each time since they trained at a lower intensity. Stolen notes that this form of training also resulted in several health improvements.

But, he emphasizes, the vast majority of improvements were greater with interval training. “For example, we were able to induce cardiac fibrillation in five of eight rats after a period of moderate exercise, and their pumping capacity had only improved half as much as in the interval training group.”

Dr Yaniv Hanoch, Associate Professor in Risk Management at the University of Southampton who led the study explained, “We know that peer pressure can lead to higher risk-taking behaviour. With the ever-increasing scale of interaction between humans and technology, both online and physically, it is crucial that we understand more about whether machines can have a similar impact.”

This new research, published in the journal Cyberpsychology, Behavior, and Social Networking, involved 180 undergraduate students taking the Balloon Analogue Risk Task (BART), a computer assessment that asks participants to press the spacebar on a keyboard to inflate a balloon displayed on the screen. With each press of the spacebar, the balloon inflates slightly, and 1 penny is added to the player’s “temporary money bank.” The balloons can explode randomly, meaning the player loses any money they have won for that balloon and they have the option to “cash-in” before this happens and move on to the next balloon.

One-third of the participants took the test in a room on their own (the control group), one third took the test alongside a robot that only provided them with the instructions but was silent the rest of the time and the final, the experimental group, took the test with the robot providing instruction as well as speaking encouraging statements such as “why did you stop pumping?”

The results showed that the group who were encouraged by the robot took more risks, blowing up their balloons significantly more frequently than those in the other groups did. They also earned more money overall. There was no significant difference in the behaviours of the students accompanied by the silent robot and those with no robot.

Dr Hanoch said: “We saw participants in the control condition scale back their risk-taking behaviour following a balloon explosion, whereas those in the experimental condition continued to take as much risk as before. So, receiving direct encouragement from a risk-promoting robot seemed to override participants’ direct experiences and instincts.”

The researcher now believe that further studies are needed to see whether similar results would emerge from human interaction with other artificial intelligence (AI) systems, such as digital assistants or on-screen avatars.

Dr Hanoch concluded, “With the wide spread of AI technology and its interactions with humans, this is an area that needs urgent attention from the research community.”

“On the one hand, our results might raise alarms about the prospect of robots causing harm by increasing risky behavior. On the other hand, our data points to the possibility of using robots and AI in preventive programs, such as anti-smoking campaigns in schools, and with hard to reach populations, such as addicts.”

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Materials provided by University of Southampton. Note: Content may be edited for style and length.

Research into nanoparticles capable of emitting light, such as quantum dots, has been an active area of interest for the last decade and a half. These particles, or phosphors, are nanoparticles made out of various materials that are capable of emitting light at specific wavelengths by leveraging quantum mechanical properties of the materials. This provides new ways to develop lighting and display solutions as well as more precise detection and sensing in instruments.

As technology becomes smaller and more sophisticated, the usage of fluorescent nanoparticles has seen a dramatic increase in many applications due to the purity of the colors emitting from the dots as well as their tunability to meet desired optical properties.

Carbon dots, a type of fluorescent nanoparticles, have seen an increase in interest from researchers as a candidate to replace non-carbon dots, the construction of which requires heavy metals that are toxic to the environment. Since they are made up of mostly carbon, the low toxicity is an extremely attractive quality when coupled with the tunability of their inherent optical properties.

Another striking feature of carbon dots is their capability to emit multiple wavelengths of light from a single nanoparticle. This multi-wavelength emission can be stimulated under a single excitation source, enabling the simple and robust generation of white light from a single particle by emitting multiple wavelengths simultaneously.

Carbon dots also exhibit a concentration-dependent photoluminescence. In other words, the distance between individual carbon dots affects the light that the carbon dots subsequently emit under an excitation source. These combined properties make carbon dots a unique source that will result in extremely accurate detection and sensing.

This concentration-dependency, however, had not been fully understood. In order to fully utilize the capabilities of carbon dots, the mechanisms that govern the seemingly variable optical properties must first be uncovered. It was previously theorized that the concentration-dependency of carbon dots was due to a hydrogen bonding effect.

Now, a KAIST research team, led by Professor Do Hyun Kim of the Department of Chemical and Biomolecular Engineering has posited and demonstrated that the dual-color-emissiveness is instead due to the interparticle distances between each carbon dot. This study was made available online in June 2020 ahead of final publication in the 36th Issue of Physical Chemistry Chemical Physics on September 28, 2020.

First author of the paper, PhD candidate Hyo Jeong Yoo, along with Professor Kim and researcher Byeong Eun Kwak, examined how the relative light intensity of the red and blue colors changed when varying the interparticle distances, or concentration, of the carbon dots. They found that as the concentration was adjusted, the light emitted from the carbon dots would transform. By varying the concentration, the team was able to control the relative intensity of the colors, as well as emit them simultaneously to generate a white light from a single source.

“The concentration-dependence of the photoluminescence of carbon dots on the change of the emissive origins for different interparticle distances has been overlooked in previous research. With the analysis of the dual-color-emission phenomenon of carbon dots, we believe that this result may provide a new perspective to investigate their photoluminescence mechanism,” Yoo explained.

The newly analyzed ability to control the photoluminescence of carbon dots will likely be heavily utilized in the continued development of solid-state lighting applications and sensing.

A trial led by UniSA stroke researcher Dr Brenton Hordacre has found that large doses of repetitive transcranial magnetic stimulation (rTMS) significantly improve post-stroke depression by increasing brain activity.

Previous studies have experimented with the use of rTMS but this is the first time that a large treatment dose — 30,000 electromagnetic pulses delivered over two weeks — have been trialled, showing positive changes in brain function.

The findings, published in the Journal of Neurology, could signal a non-invasive, alternative treatment for post-stroke depression in place of medication, which can have negative side effects for many people.

South Australians are set to benefit from this research with the brain stimulation device now available at UniSA’s City West campus to treat stroke patients suffering depression.

The $40,000 brain stimulator, partly funded by the Honda Foundation, could also potentially improve motor recovery, helping stroke patients develop new connections in the damaged brain.

“The advantage of using TMS to treat depression is that it has relatively few side effects compared to pharmacological treatments,” Dr Hordacre says. “It can also be delivered over several sessions but the improvements in depression last well beyond that period.”

An estimated 500,000 people in Australia are living with the effects of a stroke, and this figure jumps by 56,000 each year as a result of people suffering either an ischaemic (clot) stroke or a cerebral haemorrhage (bleed).

One in three people experience depression within five years of their stroke, mostly in the first year, although it can occur at any time.

“A stroke is a life-changing event in itself, bringing about personality, mood and emotional changes, so there is a very strong link between stroke, depression and anxiety,” Dr Hordacre says.

Antidepressants and psychotherapy are commonly used to treat depression post-stroke, but rTMS gives patients another option in the wake of these findings.

Adelaide resident Saran Chamberlain was one of 11 chronic stroke survivors who took part in Dr Hordacre’s trial, receiving 10 sessions of high frequency rTMS for depression.

Saran suffered a stroke in 2013 at the age of 38. She was not a typical candidate (non-smoker, healthy and young) but a stressful job and long work hours are believed to be the main factors in her case.

She was initially left completely paralysed on the left side, and was prescribed medication to deal with the ensuing depression.

“When I heard about this trial using repetitive brain stimulation I was keen to try it to see if it made any difference,” Saran said. “It did, and the effects lasted several months. I am still on antidepressants but I have reduced the dosage quite markedly. This really has made a difference to my life!”

Dr Hordacre says the benefits of UniSA’s brain stimulation device will extend beyond the community, with the university’s allied health students trained to deliver the treatment under supervision.

The treatment will be officially launched in the new year.

The study was spearheaded by principal investigator, Auriel Willette, an assistant professor in Food Science and Human Nutrition, and Brandon Klinedinst, a Neuroscience PhD candidate working in the Food Science and Human Nutrition department at Iowa State. The study is a first-of-its-kind large scale analysis that connects specific foods to later-in-life cognitive acuity.

Willette, Klinedinst and their team analyzed data collected from 1,787 aging adults (from 46 to 77 years of age, at the completion of the study) in the United Kingdom through the UK Biobank, a large-scale biomedical database and research resource containing in-depth genetic and health information from half-a-million UK participants. The database is globally accessible to approved researchers undertaking vital research into the world’s most common and life-threatening diseases.

Participants completed a Fluid Intelligence Test (FIT) as part of touchscreen questionnaire at baseline (compiled between 2006 and 2010) and then in two follow-up assessments (conducted from 2012 through 2013 and again between 2015 and 2016). The FIT analysis provides an in-time snapshot of an individual’s ability to “think on the fly.”

Participants also answered questions about their food and alcohol consumption at baseline and through two follow-up assessments. The Food Frequency Questionnaire asked participants about their intake of fresh fruit, dried fruit, raw vegetables and salad, cooked vegetables, oily fish, lean fish, processed meat, poultry, beef, lamb, pork, cheese, bread, cereal, tea and coffee, beer and cider, red wine, white wine and champaign and liquor.

Here are four of the most significant findings from the study:

1. Cheese, by far, was shown to be the most protective food against age-related cognitive problems, even late into life;
2. The daily consumption of alchohol, particularly red wine, was related to improvements in cognitive function;
3. Weekly consumption of lamb, but not other red meats, was shown to improve long-term cognitive prowess; and
4. Excessive consumption of salt is bad, but only individuals already at risk for Alzheimer’s Disease may need to watch their intake to avoid cognitive problems over time.

“I was pleasantly surprised that our results suggest that responsibly eating cheese and drinking red wine daily are not just good for helping us cope with our current COVID-19 pandemic, but perhaps also dealing with an increasingly complex world that never seems to slow down,” Willette said. “While we took into account whether this was just due to what well-off people eat and drink, randomized clinical trials are needed to determine if making easy changes in our diet could help our brains in significant ways.”

Klinedinst added, “Depending on the genetic factors you carry, some individuals seem to be more protected from the effects of Alzheimers, while other seem to be at greater risk. That said, I believe the right food choices can prevent the disease and cognitive decline altogether. Perhaps the silver bullet we’re looking for is upgrading how we eat. Knowing what that entails contributes to a better understanding of Alzheimer’s and putting this disease in a reverse trajectory.”

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Materials provided by Iowa State University. Note: Content may be edited for style and length.

These super-chilly gases follow the seemingly counterintuitive rules of quantum mechanics, featuring exact units, or quanta, of energy and often-exotic motions. Thus, the ability to control chemical reactions in stable quantum gases could enable the design of novel chemicals and gases, new platforms for quantum computers using molecules as information-rich qubits (quantum bits), and new tools for precision measurement such as molecular clocks.

The advance is described in the Dec. 11 issue of Science. JILA is jointly operated by the National Institute of Standards and Technology (NIST) and the University of Colorado Boulder.

“The molecular collisions in our experiment are very quantum mechanical, with their trajectories all quantized in terms of the way in which they can approach each other,” NIST/JILA Fellow Jun Ye said. “This is very different from a warm gas where molecules can approach each other randomly.”

The new work follows up on Ye’s many previous achievements with ultracold quantum gases . In particular, the advance builds on JILA’s simplified scheme for nudging molecular gases down to their lowest energy state, called quantum degeneracy, in which the molecules start acting like overlapping waves that all interact.

The latest JILA experiments created a dense gas of tens of thousands of potassium-rubidium molecules within a six-electrode assembly, which researchers used to generate a tunable electric field. The molecules were confined in a stack of pancake-shaped laser traps called an optical lattice , but were free to collide within each pancake, like people skating on an ice rink, Ye said.

Collisions between molecules often result in chemical reactions that rapidly deplete the gas. However, the JILA team found that molecules could be “shielded” from these chemical reactions by turning a simple knob — the strength of the electric field. The shielding is due to the electric field modifying the rotations and interactions of the molecules.

The molecules repel each other because they are fermions, a class of particles that cannot be in the same quantum state and location at the same time. But the molecules can interact because they are polar, with a positive electric charge at the rubidium atom and a negative charge at the potassium atom. The opposing charges create electric dipole moments that are sensitive to electric fields. When the molecules collide head to tail, with opposing charges, chemical reactions rapidly deplete the gas. When the molecules collide side by side, they repel each other.

The JILA team started by preparing a gas in which each molecule was spinning with exactly one quantum unit of rotation. Thus, each molecule acted like a tiny quantum top, spinning around its axis, with only certain values of angular momentum (or speeds of rotation) allowed by quantum mechanics. By changing the electric field, the researchers found special fields (“resonances”) where two colliding, spinning molecules could exchange their rotations, leaving one molecule spinning twice as fast and the other not spinning at all.

The ability to exchange rotations completely altered the nature of the collisions, causing the forces between colliding molecules to change rapidly from attractive to repulsive near the resonances. When the interactions between molecules were repulsive, the molecules were shielded from loss, since they rarely came close enough to chemically react. When the interactions were attractive, the chemical reaction rate was dramatically enhanced.

Near the resonances, the JILA team observed nearly a thousandfold change in the chemical reaction rate when tuning the electric field strength by just a few percent. With the strongest shielding, the chemical reaction rate was reduced to a tenth of the normal background value, creating a stable, long-lived gas.

This is the first demonstration of use of an electric field to resonantly control how molecules interact with each other. The experimental results agreed with theoretical predictions. JILA researchers expect their techniques to remain effective without the optical lattice, which will simplify future efforts to create molecular gases made of other types of atoms.

A collaborator from the Paris-Saclay University, Orsay, France, made the theoretical calculations. Funding was provided by NIST, the Defense Advanced Research Projects Agency, the Army Research Office, and the National Science Foundation.