UCI-led Study Finds Unleashing Certain T Cells May Lead To New Treatments For Multiple Sclerosis (Medicine)

In a new University of California, Irvine-led study, researchers found that a certain protein prevented regulatory T cells (Tregs) from effectively doing their job in controlling the damaging effects of inflammation in a model of multiple sclerosis (MS), a devastating autoimmune disease of the nervous system. 

Published this month in Science Advancesthe new study illuminates the important role of Piezo1, a specialized protein called an ion channel, in immunity and T cell function related to autoimmune neuroinflammatory disorders.

“We found that Piezo1 selectively restrains Treg cells, limiting their potential to mitigate autoimmune neuroinflammation,” said Michael D. Cahalan, PhD, distinguished professor and chair in the Department of Physiology & Biophysics at the UCI School of Medicine.  “Genetically deleting Piezo1 in transgenic mice, resulted in an expanded pool of Treg cells, which were more capable of effectively reducing neuroinflammation and with it the severity of the disease.”

T cells rely on specialized proteins, like Piezo1, to detect and respond to various diseases and conditions including bacterial infections, wound healing, and even cancer.  Uncontrolled T cell activity, however, can give rise to autoimmune disorders in which the immune system attacks normal cells in the body. Tregs constantly curate immune responses and play a critical role in preventing autoimmunity. 

“Given the demonstrated ability of Piezo1 to restrain Treg cells, we believe that inhibiting Piezo1 could lead to new treatments for neuroinflammatory disorders, like MS,” explained Amit Jairaman, PhD, and Shivashankar Othy, PhD, lead authors of the study, both project scientists in the Department of Physiology & Biophysics.

Piezo1 conducts ions when cells are subjected to mechanical forces. Research over the last decade has shed light on the role of Piezo1 in regulating vital physiological functions including red blood cell (RBC) volume, blood pressure, vascular development, bone formation, and differentiation of neural stem cells. However, its role in modulating immune response has not been appreciated before. And, while it was known that calcium conducting ion channels, like Piezo1, direct various aspects of T cell function, researchers were surprised to find that Piezo1 was not essential for a whole host of T cell functions that rely on calcium, such as lymph node homing, interstitial motility, activation, proliferation, or differentiation into effector T cells.

“We found the role of Piezo1 appears to be quite specific to Tregs. Therefore, targeting Piezo1 might be a new and ideal strategy to cure MS while preserving the immune system’s ability to fight new infections,” added Othy, whose research over last 12 years has focused on finding ways to harness the therapeutic potential of Treg cells.

Further investigation of the function of Piezo1 is needed to understand therapeutic potential, and to more fully understand the processes through which cells sense and respond to mechanical stimuli during immune responses.

This research was supported by funding from the National Institutes of Health, the Howard Hughes Medical Institute and the Hewitt Foundation for Biomedical Research.

Featured image: Genetic deletion of Piezo1 in T cells leads to protection in autoimmunity: In the absence of Piezo1, Tregs expand more and, due to their increased numbers, are more effective in containing the damage inflicted by the effector T cells during an autoimmune neuroinflammation. Effector T cell function is not affected in the absence of Piezo1. © UCI School of Medicine


Provided by UCI School of Medicine

Child With Rare Genetic Syndrome Successfully Treated in Less Than Two Years (Medicine)

New rare genetic syndrome goes from a collection of symptoms to successful treatment in less than two years

Diagnosing a rare medical condition is difficult.  Identifying a treatment for it can take years of trial and error. In a serendipitous intersection of research expertise, an ill patient in this case a child and innovative technology, Bachmann-Bupp Syndrome has gone from a list of symptoms to a successful treatment in just 16 months.  

The paper chronicling this lightning-fast scientific response to Bachmann-Bupp Syndrome was published on July 13 in the open-access journal, eLife.  

Andre Bachmann
Andre Bachmann © MSU

For more than 25 years, André Bachmann, professor of pediatrics in Michigan State University College of Human Medicine, had been studying the ODC1 gene. This gene and its protein product ODC, which produces polyamines are crucial for cell survival and contribute to many developmental processes, including muscle tone and motor skills in children.  

Through Bachmann’s research, he also knew that the drug difluoromethylornithine, or DFMO, (sometimes referred to as eflornithine), had already been successful and approved by the Food and Drug Administration for treating other diseases linked to problems with ODC like African sleeping sickness and hirsutism (excessive hair growth). It was also studied in cancer clinical trials of colon cancer and pediatric neuroblastoma.

Caleb Bupp
Caleb Bupp © MSU

In 2018, Caleb Bupp, a medical geneticist at Helen DeVos Children’s Hospital in Grand Rapids and clinical assistant professor in the Department of Pediatrics and Human Development in Michigan State University College of Human Medicine, had an unusual patient. Three-year-old Marley Berthoud’s symptoms included a large head size, complete hair loss, low muscle tone and developmental delays. She could not hold her head up, feed herself, crawl or communicate.

When Bupp sequenced Marley’s exome (the part of the human genome that contains the genetic code for making proteins), he discovered a mutation on her ODC1 gene. Bupp recalled a presentation by Surender Rajasekaran, a pediatric ICU physician at Helen DeVos and assistant professor in the Department of Pediatrics and Human Development in the Michigan State University College of Human Medicine, and Bachmann about ODC1, and he reached out to them.

Marley’s ODC1 gene mutation caused her body to accumulate lots of ODC protein which was building up in her system. Bachmann knew from his previous work that DFMO deactivates ODC proteins.  

“We can’t stop her body from accumulating ODC protein, but we can make the protein inactive,” Bachmann said.

Bupp was encouraged by Bachmann’s previous research showing that DFMO was safe and had minimal side effects on patients, especially children. With her family’s approval, Marley started taking DFMO in 2019. This was the first FDA-approved single-patient study in the world to treat a patient with an ODC1 mutation using DFMO.  

“From the discovery of the syndrome until the patient’s first dose it took less than two years,” Bachmann said. “That doesn’t usually happen so quickly.”

While Bachmann, Bupp, Rajasekaran and Berthoud’s family waited to see if DFMO would work, Marley’s list of symptoms was given the official name of Bachmann-Bupp Syndrome or BABS by the Online Mendelian Inheritance in Man, an online database of human genes and genetic disorders.  

“This rarely happens,” Bachmann said. “As of today, and still many years from now, medical students will be learning about Bachmann-Bupp Syndrome and this all started at MSU.”

Since she started taking DFMO, Marley has made tremendous progress. She has gained muscle tone which means she can hold her head up, feed herself with a spoon and crawl, but the most visible sign of success has been a full head of new hair growth.  

“It’s astounding,” Bachmann said. “When I first saw a picture of her, I couldn’t believe she had grown that much hair in a year, and she managed to sled down a hill by herself.”

Seeing all of this external progress was promising but Bupp wanted to go a step further to learn more about the internal changes happening inside Marley’s body from the DFMO treatment. Bupp contacted Metabolon, a health technology company based in Morrisville, North Carolina, that has developed a tool for the detecting biological markers of rare diseases and response to treatment.  

Metabolon’s Precision Metabolomics technology could test Marley’s blood samples before and during treatment to find out exactly how her body’s metabolism responded to DFMO treatment and the effect the drug was having on her body.  

“There is not really a regular lab test you can do to look at that, so working with Metabolon gave us that window into Marley’s biochemistry that wouldn’t have been possible otherwise,” Bupp said. “What we saw in the numbers agreed with what we were observing with our eyes — Her body was changing on the inside too.”

The result of what was happening inside Marley’s body confirmed that DFMO works and was just as impressive as what was happening on the outside.

“Now Marley is using some sign language, where previously she couldn’t communicate,” Bupp said. “My heart melted when she was able to give me a high five for the first time.”

Featured image: Marley Berthoud can hold her head up, scoot around on the floor and communicate using some American Sign Language © Spectrum Health Beat


Provided by Michigan State University

Brain ‘Noise’ Keeps Nerve Connections Young (Neuroscience)

Neurons communicate through rapid electrical signals that regulate the release of neurotransmitters, the brain’s chemical messengers. Once transmitted across a neuron, electrical signals cause the juncture with another neuron, known as a synapse, to release droplets filled with neurotransmitters that pass the information on to the next neuron. This type of neuron-to-neuron communication is known as evoked neurotransmission.

However, some neurotransmitter-packed droplets are released at the synapse even in the absence of electrical impulses. These miniature release events — or minis — have long been regarded as ‘background noise’, says Brian McCabe, Director of the Laboratory of Neural Genetics and Disease and a Professor in the EPFL Brain Mind Institute.

But several studies have suggested that minis do have a function — and an important one. In 2014, for example, McCabe and his team showed that minis are important for the development of synapses. If neurons in the brain were a network of computers, evoked releases would be packets of data through which the machines exchange information, whereas minis would be pings — brief electronic signals that determine if there is a connection between two computers, McCabe says. “Minis are the pings that neurons use to say ‘I am connected.'”

Adult Drosophila motor terminals (green) and muscles (red) progressively degenerate with age © Laboratory of Neural Genetics and Disease / EPFL

To assess whether minis could play a role in the mature nervous system, Soumya Banerjee, a postdoc in McCabe’s group, and his colleagues set out to study a set of neurons that control movement in fruit flies. As the insects aged, their synapses started to break up into smaller fragments, the researchers found. (A similar process occurs in aging mammals, including people.) As nerve junctions broke down, both evoked and miniature neurotransmission were dampened, and the flies showed motor problems such as a reduced ability to climb the walls of a plastic vial.

Next, the team assessed the effects of stimulating or inhibiting evoked and miniature neurotransmission. When both types of neurotransmission were blocked, synapses aged prematurely, suggesting that during aging or in neurological diseases associated with old age, changes in neurotransmission happen before synapses start to crumble. This finding, McCabe says, upends a longstanding idea in neuroscience. “The idea has long been that the structure of the synapse breaks down, and that causes a functional change in the synapse, but we found it is the other way around,” he says.

Adult Drosophila neuromuscular synaptic terminals. Motor neurons (blue), synaptic boutons (red) and neurotransmitter release sites (green). © Laboratory of Neural Genetics and Disease / EPFL

Stimulating evoked neurotransmission alone had no effect on aging synapses, the researchers found. However, increasing the frequency of minis kept synapses intact and preserved the motor ability of middle-aged flies at levels comparable to those of young flies. “Motor ability declines in all aging animals, including humans, so it was a delightful surprise to see that we could change that,” McCabe says.

The findings, published in Nature Communications, could have important implications for human health: minis have been found at every type of synapse studied so far, and defects in miniature neurotransmission have been linked to range of neurodevelopmental disorders in children. Figuring out how a reduction in miniature neurotransmission changes the structure of synapses, and how that in turn affects behavior, could help to better understand neurodegenerative disorders and other brain conditions.

Featured image: Brian McCabe, Director of the Laboratory of Neural Genetics and Disease and a Professor in the EPFL Brain Mind Institute. © Alain Herzog / EPFL


Reference: Banerjee, S., Vernon, S., Jiao, W. et al. Miniature neurotransmission is required to maintain Drosophila synaptic structures during ageing. Nat Commun 12, 4399 (2021). https://doi.org/10.1038/s41467-021-24490-1


Provided by EPFL

Spinal Fluid Biomarkers Detect Neurodegeneration, Alzheimer’s Disease in Living Patients (Neuroscience)

Alzheimer’s Disease and other forms of neurodegeneration can be identified using a combination of biomarkers in cerebrospinal fluid of living patients, Penn researchers find

Alzheimer’s disease and related diseases can still only be confirmed in deceased patients’ brains via autopsy. Even so, the development of biomarkers can give patients and their families answers during life: Alzheimer’s disease can be accurately detected via peptides and proteins in a patient’s cerebrospinal fluids (CSF), which can be collected through a lumbar puncture and tested while the patient is alive. In 2018, a new framework suggested combining three Alzheimer’s disease biomarkers in CSF – pathologic amyloid plaques (A), tangles (T), and neurodegeneration (N), collectively called ATN. According to recent research from the Perelman School of Medicine at the University of Pennsylvania, the ATN framework can be extended to detect another neurodegenerative condition: frontotemporal degeneration.

Patients with frontotemporal degeneration can experience a range of symptoms, including behavioral changes, executive dysfunction, and language impairments. Distinguishing frontotemporal degeneration from Alzheimer’s disease can be a challenge for clinicians: the symptoms of frontotemporal degeneration can sometimes overlap with Alzheimer’s disease, and a subset of patients can even have both pathologies. Biomarkers can fill the gap by providing evidence of whether Alzheimer’s pathology underlies a patient’s symptoms.

“CSF biomarkers work similarly to a pregnancy test, offering a simple positive or negative result when enough of a substance is detected. But like a pregnancy test, biomarkers for Alzheimer’s disease can provide false negatives or positives,” said lead investigator Katheryn A.Q. Cousins, PhD, a research associate in the Frontotemporal Degeneration Center in the Department of Neurology at Penn Medicine. “Alzheimer’s is a diverse disease, and it is common for other conditions to also be present in the brain. The ATN framework may provide a more complete look at a person’s diagnosis and give us a much richer understanding of not only Alzheimer’s disease, but other co-occurring neurodegenerative conditions. However, to accomplish this, additional biomarkers that can detect other neurodegenerative conditions are critically needed.”

The findings, published in Alzheimer’s and Dementia: The Journal of the Alzheimer’s Association, show that ATN incorporating neurofilament light chain (NfL) may provide a more accurate and precise diagnosis for patients with frontotemporal degeneration. NfL is a protein abundant in the brain, whose levels increase as degeneration progresses. Cousins’ work shows that CSF NfL may be a more accurate marker of neurodegeneration for patients with frontotemporal degeneration, including for Alzheimer’s disease.

“While the ATN framework is very exciting and offers much opportunity for patients with Alzheimer’s disease, these biomarkers don’t capture every case of the disease. We want to be able to detect and treat every patient with neurodegenerative disease as early as possible, and more research is needed to fully understand how biofluids track with the disease process,” said Cousins. “I am eager to conduct additional research into which patients might be missed by these markers, what they have in common, and what causes the pathological and clinical differences in the disease.”

This study was funded by the Swedish Research Council (2018-02532); the European Research Council, (681712); Swedish State Support for Clinical Research (ALFGBG-720931); the Alzheimer Drug Discovery Foundation (201809-2016862); the Swedish Alzheimer Foundation, (AF-742881); European Union Joint Program for Neurodegenerative Disorders (JPND2019-466-236); and the Alzheimer’s Association Research Fellowship (AARF-16-44368).


Provided by Penn Medicine

A Foot Tumour And Two Tail Fractures Complicated The Life of This Hadrosaur (Paleontology)

When it was discovered in the 1980s in Argentina, this hadrosaur was diagnosed with a fractured foot. However, a new analysis now shows that this ornithopod commonly known as the duck-billed dinosaur actually had a tumour some 70 million years ago, as well as two painful fractures in the vertebrae of its tail, despite which, it managed to survive for some time.

This dinosaur, called Bonapartesaurus rionegrensis, was discovered in Argentinean Patagonia in the 1980s, and the first analyses of its fossils indicated an ailment of the foot, possibly a fracture, as the Argentinean palaeontologist Jaime Powell pointed out at the time. The study of this animal then came to a standstill until 2016, when Powell invited another team of scientists to resume the research.

The presence of diseases such as tumours confirms that they already existed at a very early age and among a very diverse group of animals

“In addition to the ailment of the foot, there were other possible fractures in several neural spines of the vertebrae of the tail,” as Penélope Cruzado-Caballero, the lead author of the study, now published in the journal Cretaceous Research, and a scientist at the Research Institute of Palaeobiology and Geology of CONICET and the National University of Río Negro (Argentina), as well as a professor at the University of La Laguna (Tenerife, Spain), has told SINC. 

The researchers decided to analyse them all to see this hadrosaur, also known as duck-billed dinosaur, “during its lifetime” and to see how it was able to interact with the environment, with its fellows, and with predators while suffering from these problems. 

Scientists were particularly surprised by the condition of the foot. “We were struck by the large overgrowth of bone that gave it a cauliflower-like appearance and covered almost the entire metatarsal,” the researcher points out. When studying the histology and CT scans of the fossil, the team did not find a fracture. Instead, the indicators showed a reduction in bone density and several areas where cortical tissue had been destroyed. 

“We were probably looking at a cancer or a neoplasm, such as an osteosarcoma,” specifies Cruzado-Caballero. The presence of diseases such as tumours confirms that they already existed at a very early age and among a very diverse group of animals.

“Despite the large development of the cancer, it did not significantly affect the muscle insertion zone, so we cannot be sure that the lesion affected its locomotion,” says the palaeontologist. The study has allowed us to determine that the tumour did not spread to other bones – since this ornithopod preserved almost half of its skeleton -, “so, although it severely affected the metatarsus, it did not cause its death,” she adds.

Tail fractures followed by infections

In addition to the foot tumour, other pathologies were identified in the neural spines of two vertebrae in Bonapartesaurus rionegrensis’s tail. According to the scientists, one of the vertebrae had a displaced fracture that had almost healed. “It was probably related to an injury resulting from a strong blow that caused the bone to be displaced and to heal in this manner, giving the spine a curved appearance,” Cruzado-Caballero stresses.

In addition to the foot tumour, other pathologies were identified in the neural spines of two vertebrae in Bonapartesaurus rionegrensis’s tail.

The other vertebra had an almost completely healed fracture also produced by a stress event (it is not known if it was due to impact), which did not lead to the displacement of the bone. Although the spine maintains its straight shape, the researchers observed a swelling that formed a callus on the bone as it healed. 

“These fractures, especially in the case of the displaced fracture, must have been associated with infections following the rupture of the muscles surrounding the bone,” says the researcher, who considers that they must have been painful not only because of the blow, but also because of the infections that could have impeded the mobility of the tail and caused this specimen a great deal of discomfort when it moved. 

However, despite the severity of the ailments, the death of Bonapartesaurus rionegrensis did not follow immediately after its injuries, the authors point out. “But we cannot quantify how long it lived afterwards, which means that it could have lived for months or years. Nor can we confirm that these injuries were the final cause of its death,” comments the scientist. 

This hadrosaur, although badly injured, therefore managed to survive and continued to interact with its fellows, despite the initial pain caused by fractures and infections. These could have been caused by falling, hitting an object or another animal to defend itself from predators, or even by being trampled on the tail by another hadrosaur. 

Featured image: Despite the seriousness of its foot and tail vertebrae ailments, Bonapartesaurus rionegrensis did not die immediately after its injuries / José Antonio Peñas (SINC)


Reference:

Penélope Cruzado-Caballero et al. “Osseous paleopathologies of Bonapartesaurus rionegrensis (Ornithopoda, Hadrosauridae) from Allen Formation (Upper Cretaceous) of Patagonia Argentina” Cretaceous Research


Provided by SINC

Scientists Uncover How Molecule Improves Appearance of Surgery Scars (Medicine)

In a new study led by Rob Gourdie, researchers discovered that the alphaCT1 molecule may help repair the skin’s collagen matrix by altering how scar-forming cells behave.

Surgical scars treated with a molecule called alphaCT1 showed a long-term improvement in appearance when compared to control scars, according to multicenter, controlled Phase II clinical trials – a finding that could help surgeons improve patient outcomes.

Now, a public-private research team led by Rob Gourdie, professor and director of the Center for Vascular and Heart Research at the Fralin Biomedical Research Institute at VTC, has revealed clues about why and how it improves the appearance of scars.

The study, scheduled to appear in the August issue of the Federation of American Societies for Experimental Biology (FASEB) Journal, describes how the drug influences the behavior of collagen-producing cells called fibroblasts. The findings reveal a previously unreported feature of scar formation and could help advance wound healing treatments for patients undergoing surgical procedures.

The researchers analyzed scars from 49 healthy volunteers in a randomized, double-blind Phase I clinical study. Each volunteer had 5-milimeter punches of skin biopsied from each of their inner biceps. One arm’s wound was treated with the alphaCT1 molecule in a gel, and the other received a nonmedicated control gel. The wounds healed for 29 days, at which point the scars were photographed and biopsied again.

Under the microscope, the untreated scars’ collagen – a protein produced by cells called fibroblasts – formed parallel strips, which makes the tissue less pliable. By contrast, scars that were applied with the drug had a collagen matrix resembling unwounded skin. Related experiments were repeated using guinea pig and rat models and yielded similar results.

The researchers also analyzed human skin cells cultured in a dish to watch how the drug influenced cellular activity in real time. They discovered that the presence of the molecule caused fibroblasts to stretch out like a rubber band, then snap back into shape and change direction.

“We call it the fibroblast dance,” said Gourdie, who is also the Commonwealth Research Commercialization Fund Eminent Scholar in Heart Reparative Medicine Research and a professor of biomedical engineering and mechanics in Virginia Tech’s College of Engineering.

This unusual fibroblast behavior in the treated tissue appears to have a positive effect on scar formation, Gourdie said.

“In unwounded skin, the collagen is enmeshed, allowing the tissue to move and stretch in all directions. The fibroblasts’ directional changes appear to influence how the collagen matrix forms during scarring,” Gourdie said.

Fibroblast dance
Fibroblasts treated with alphaCT1 respond by doing what Gourdie describes as the “fibroblast dance.” The cells undergo pivoting motions that result in frequent direction changes. Gourdie speculates this unusual pattern of cellular movement dictates how the cells knit the collagen bundles together that will form the scar. (Gourdie Lab / Virginia Tech)

More than 300 million surgical procedures are performed in the United States each year – often resulting in noticeable scarring on patients. Methods to reduce scarring after operations are sought after.

“This is some of the most exciting basic science research in wound healing I’ve seen in a long time,” said Kurtis Moyer, chief of plastic and reconstructive surgery for Carilion Clinic and a professor of surgery at the Virginia Tech Carilion School of Medicine. Moyer was not involved in the study, but has collaborated with the Gourdie lab on wound healing research for 20 years.

“This shows real promise and could potentially revolutionize what we do in plastic surgery,” Moyer said.

AlphaCT1 influences wound healing by temporarily interrupting cell signaling functions of connexin 43, a gap junction channel protein.

Gourdie and his lab invented the molecule and discovered its useful effects on wound healing with his former postdoctoral associate, Gautam Ghatnekar, a decade ago. Together they formed a biopharmaceutical company, FirstString Research Inc., to bring alphaCT1 to market.

The molecule is currently being evaluated in Phase III clinical testing in bilateral breast surgery patients.

“These findings validate that the drug’s mechanism is playing out as we thought it would,” said Ghatnekar, FirstString’s president and chief executive officer.

The company has closed $55 million in Series B, C, and D Funding since 2018 and is evaluating the drug’s use in a variety of applications, including surgical wound healing, chronic wound healing, radiation therapy wound healing, and corneal tissue repair.

“We alter how the human body responds to injury by shifting the balance from healing by scarring to healing by regeneration. The medical applications for our technology are far-ranging,” Ghatnekar said.

Gourdie and Ghatnekar were joined on the study by its first author, Jade Montgomery, a former graduate student in Gourdie’s lab at the Fralin Biomedical Research Institute and in Virginia Tech’s Department of Biomedical Engineering and Mechanics; William Richardson, an assistant professor of bioengineering at Clemson University; Spencer Marsh, a postdoctoral associate in Gourdie’s lab; Matthew Rhett, a staff scientist at the Medical University of South Carolina at the time of the study; Francis Bustos, a former medical student; Katherine Degen, a former graduate student in Gourdie’s lab at the Fralin Biomedical Research Institute and in the Virginia Tech – Wake Forest School of Biomedical Engineering and Sciences; Christina Grek, senior director of research and development at FirstString; Jane Jourdan, Gourdie’s lab manager; and Jeffrey Holmes, dean of engineering at the University of Alabama.

Featured image: In a new study, Fralin Biomedical Research Institute at VTC scientists discovered that the alphaCT1 molecule may help repair the skin’s collagen matrix. Microscopic imaging of 29-day scar biopsies from the same patient reveals the molecule’s effects on collagen organization. Collagen bundles in the untreated scar, right, are more aligned compared to the alphaCT1-treated tissue’s collagen, which is more randomly arranged in swirls that resemble unwounded skin. (Gourdie Lab / Virginia Tech)


Reference: Montgomery, J, Richardson, WJ, Marsh, S, et al. The connexin 43 carboxyl terminal mimetic peptide αCT1 prompts differentiation of a collagen scar matrix in humans resembling unwounded skin. The FASEB Journal. 2021; 35:e21762. https://doi.org/10.1096/fj.202001881R


Provided by Virginia Tech

How Negatively Charged Molecules Are Created in Interstellar Environments? (Physics)

Interstellar clouds are the birthplaces of new stars, but they also play an important role in the origins of life in the Universe through regions of dust and gas in which chemical compounds form. The research group, molecular systems, led by ERC prize winner Roland Wester at the Institute for ion physics and applied physics at the University of Innsbruck, has set itself the task of better understanding the development of elementary molecules in space. “Put simply, our ion trap allows us to recreate the conditions in space in our laboratory,” explains Roland Wester. “This apparatus allows us to study the formation of chemical compounds in detail.” The scientists working with Roland Wester have now found an explanation for how negatively charged molecules form in space.

An idea built on theoretical foundations

Before the discovery of the first negatively charged carbon molecules in space in 2006, it was assumed that interstellar clouds only contained positively charged ions. Since then, it has been an open question how negatively charged ions are formed. The Italian theorist Franco A. Gianturco, who has been working as a scientist at the University of Innsbruck for eight years, developed a theoretical framework a few years ago that could provide a possible explanation. The existence of weakly bound states, so-called dipole-bound states, should enhance the attachment of free electrons to linear molecules. Such molecules have a permanent dipole moment which strengthens the interaction at a relatively great distance from the neutral nucleus and boosts the capture rate of free electrons.

Observing dipole-bound states in the laboratory

In their experiment, the Innsbruck physicists created molecules consisting of three carbon atoms and one nitrogen atom, ionized them, and bombarded them with laser light in the ion trap at extremely low temperatures. They continuously changed the frequency of the light until the energy was large enough to eject an electron from the molecule. Albert Einstein described this so-called photoelectric effect 100 years ago. An in-depth analysis of the measurement data by the early-stage researcher Malcolm Simpson from the doctoral training programme, atoms, light and molecules at the University of Innsbruck finally shed light on this difficult-to-observe phenomenon. A comparison of the data with a theoretical model finally provided clear evidence of the existence of dipole-bound states. “Our interpretation is that these dipole-bound states represent a kind of door opener for the binding of free electrons to molecules, thus contributing to the creation of negative ions in space,” says Roland Wester. “Without this intermediate step, it would be very unlikely that electrons would actually bind to the molecules.”

The work was supported by the Austrian Science Fund FWF, which also finances the PhD program Atoms, Light and Molecules (ALM) at the University of Innsbruck.

Featured image: Physicists Roland Wester (left) and Malcolm Simpson (right) demonstrate how dipole-bound states allow negative ions to form in interstellar clouds. © Bryan Goff on Unsplash / AG Wester


Publication: Influence of a supercritical electric dipole moment on the photodetachment of C3N-. Malcolm Simpson, Markus Nötzold, Tim Michaelsen, Robert Wild, Franco A. Gianturco, and Roland Wester. Phys. Rev. Lett. 127, 043001, https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.127.043001


Provided by University of Innsbruck

New Method Predicts ‘Stealth’ Solar Storms Before They Wreak Geomagnetic Havoc on Earth (Planetary Science)

For the first time, stealth coronal mass ejections can be detected before they wreak havoc on Earth without the need for dedicated spacecraft

On 23 July 2012, humanity escaped technological and economic disaster. A diffuse cloud of magnetized plasma in the shape of a slinky toy tens of thousands of kilometers across was hurled from the Sun at a speed of hundreds of kilometers per second.

This coronal mass ejection (CME) just missed the Earth because its origin on the Sun was facing away from our planet at the time. Had it hit the Earth, satellites might have been disabled, power grids around the globe knocked out, GPS systems, self-driving cars, and electronics jammed, and railway tracks and pipelines damaged. The cost of the potential damage has been estimated at between $600bn and $2.6trn in the US alone.

While CMEs as large as the 2012 event are rare, lesser ones cause damage on Earth about once every three years. CMEs need between one and a few days to reach Earth, leaving us some time to prepare for the potential geomagnetic storm. Current efforts to limit any damage include steering satellites out of harm’s way or redirecting the power load of electrical grids. But many CMEs — called ‘stealth CMEs’ because they don’t produce any clear signs close to the Sun’s surface — aren’t detected until they reach Earth.

Now, an International Space Science Institute (ISSI) team of scientists from the US, Belgium, UK, and India shows how to detect potentially damaging stealth CMEs, trace them back to their region of origin on the Sun, extrapolate their trajectory, and predict if they will hit Earth. The results were recently published in the journal Frontiers in Astronomy and Space Sciences.

Visualizing the invisible

“Stealth CMEs have always posed a problem, because they often originate at higher altitudes in the Sun’s corona, in regions with weaker magnetic fields. This means that unlike normal CMEs — which typically show up clearly on the Sun as dimmings or brightenings — stealth CMEs are usually only visible on devices called coronagraphs designed to reveal the corona,” said corresponding author Dr Erika Palmerio, a researcher at the Space Sciences Laboratory of the University of California at Berkeley.

“If you see a CME on a coronagraph, you don’t know where on the Sun it came from, so you can’t predict its trajectory and won’t know whether it will hit Earth until too late.”

Palmerio continued: “But here we show that many stealth CMEs can in fact be detected in time if current analysis methods for remote sensing are adapted. Put simply, we compared ‘plain’ remote sensing images of the Sun with the same image taken between eight and 12 hours earlier, to capture very slow changes in the lower corona, up to 350,000km from the Sun’s surface. In many cases, these ‘difference images’ revealed small, previously overlooked changes in the loops of magnetic fields and plasma that are hurled from the Sun. We then zoom in on these with another set of imaging techniques to further analyze the stealth CME’s approximate origin, and predict whether it is headed towards Earth.”

Stealth CMEs leave overlooked signs

Palmerio and collaborators looked at four stealth CMEs that occurred between 2008 and 2016. Unusually for stealth CMEs, their origin on the Sun was approximately known only because NASA’s twin STEREO spacecraft, launched in 2006, had happened to capture them ‘off-limb’. This means it was viewed outside the Sun’s disc from another angle than from Earth.

With the new imaging techniques, the authors revealed previously undetected, tiny dimmings and brightenings on the Sun at the region of origin of all four stealth CMEs. They conclude that the technique can be used for the early detection of risky stealth CMEs.

“This result is important because it shows us what to look for if we wish to predict the impact on Earth from solar eruptions,” said Palmerio.

“Another important aspect of our study — using geometric techniques to locate a CME’s approximate source region and model its 3D structure as it expands and moves towards Earth — can only be implemented when we have more dedicated observatories with different perspectives, like the STEREO spacecraft.”

The authors predict that the new European Space Agency’s Solar Orbiter, launched in February 2020, will help with this, just like similar initiatives which are currently discussed by researchers worldwide.

“Data from more observatories, analyzed with the techniques developed in our study, could also help with an even more difficult challenge: namely to detect so-called ‘super stealth CMEs’, which don’t even show up on coronagraphs,” said coauthor Dr Nariaki V Nitta, a senior researcher at Lockheed Martin Solar and Astrophysics Laboratory in Palo Alto, US.

Featured image: The novel imaging techniques applied to remote sensing data of the coronal mass ejection on 08 Oct 2016. A-D: Intensity of extreme UV (EUV; 21.1 nm) captured by the Atmospheric Imaging Assembly instrument on board NASA’s Solar Dynamics Observatory. 1st column: 08 Oct 2016 15:00 UTC. 2nd column: 09 Oct 2016 00:00 UTC. 3rd column: 09 Oct 2016 09:00 UTC. 4th column: 09 Oct 2016 18:00 UTC. First row: unprocessed images. Second row: Difference images comparing EUV intensity to 12 h earlier. Third row: Images after Wavelet Packets Equalization (WPE), an image processing method. Fourth row: Images after Multi-scale Gaussian Normalization (MGN), another image processing method. Arrows denote dimmings and brightenings on the Sun’s disc, previously overlooked but revealed with the new method. © Palmerio, Nitta, Mulligan et al.


Reference: Erika Palmerio et al., “Investigating Remote-Sensing Techniques to Reveal Stealth Coronal Mass Ejections”, Front. Astron. Space Sci., 05 July 2021 | https://doi.org/10.3389/fspas.2021.695966


Provided by Frontiers

Long-period Oscillations of the Sun Discovered (Planetary Science)

Ten years of data from NASA’s Solar Dynamics Observatory combined with numerical models reveal the deep low musical notes of the Sun.

A team of solar physicists led by Laurent Gizon of the Max Planck Institute for Solar System Research (MPS) and the University of Göttingen in Germany has reported the discovery of global oscillations of the Sun with very long periods, comparable to the 27-day solar rotation period. The oscillations manifest themselves at the solar surface as swirling motions with speeds on the order of 5 kilometers per hour. These motions were measured by analyzing 10 years of observations from NASA’s Solar Dynamics Observatory (SDO). Using computer models, the scientists have shown that the newly discovered oscillations are resonant modes and owe their existence to the Sun’s differential rotation. The oscillations will help establish novel ways to probe the Sun’s interior and obtain information about our star’s inner structure and dynamics. The scientists describe their findings in a letter to appear today in the journal Astronomy & Astrophysics.

High-latitude inertial mode: The east-west velocity associated with the retrograde propagating mode of oscillation. Left: observations using the SDO/HMI instrument. Right: numerical model. Sound: filtered data (86 ± 10 nHz) shifted to the audible spectrum; the sound variations inform us about the excitation and damping of the mode. © MPI

In the 1960’s the Sun’s high musical notes were discovered: The Sun rings like a bell. Millions of modes of acoustic oscillations with short periods, near 5 minutes, are excited by convective turbulence near the solar surface and are trapped in the solar interior. These 5-minute oscillations have been observed continuously by ground-based telescopes and space observatories since the mid 1990’s and have been used very successfully by helioseismologists to learn about the internal structure and dynamics of our star – just like seismologists learn about the interior of the Earth by studying earthquakes. One of the triumphs of helioseismology is to have mapped the Sun’s rotation as a function of depth and latitude (the solar differential rotation).

In addition to the 5-minute oscillations, much longer-period oscillations were predicted to exist in stars more than 40 years ago, but had not been identified on the Sun until now. “The long-period oscillations depend on the Sun’s rotation; they are not acoustic in nature”, says Laurent Gizon, lead author of the new study and director at the MPS. “Detecting the long-period oscillations of the Sun requires measurements of the horizontal motions at the Sun’s surface over many years. The continuous observations from the Helioseismic and Magnetic Imager (HMI) onboard SDO are perfect for this purpose.”

Critical-latitude inertial mode: The east-west velocity associated with the retrograde propagating mode of oscillation. Left: observations using the SDO/HMI instrument. Right: numerical model. Sound: filtered data (73 ± 10 nHz) shifted to the audible spectrum; the sound variations inform us about the excitation and damping of the mode. © MPI

The team observed many tens of modes of oscillation, each with its own oscillation period and spatial dependence. Some modes of oscillation have maximum velocity at the poles (movie 1), some at mid-latitudes (movie 2), and some near the equator (movie 3). The modes with maximum velocity near the equator are Rossby modes, which the team had already identified in 2018. “The long-period oscillations manifest themselves as very slow swirling motions at the surface of the Sun with speeds of about 5 kilometers per hour – about how fast a person walks”, says Zhi-Chao Liang from MPS. Kiran Jain from NSO, together with B. Lekshmi and Bastian Proxauf from MPS, confirmed the results with data from the Global Oscillation Network Group (GONG), a network of six solar observatories in the USA, Australia, India, Spain, and Chile.

To identify the nature of these oscillations, the team compared the observational data to computer models. “The models allow us to look inside the Sun’s interior and determine the full three-dimensional structure of the oscillations”, explains MPS graduate student Yuto Bekki. To obtain the model oscillations, the team began with a model of the Sun’s structure and differential rotation inferred from helioseismology. In addition, the strength of the convective driving in the upper layers, and the amplitude of turbulent motions are accounted for in the model. The free oscillations of the model are found by considering small-amplitude perturbations to the solar model. The corresponding velocities at the surface are a good match to the observed oscillations and enabled the team to identify the modes (see movies).

Equatorial Rossby mode: The north-south velocity associated with the retrograde propagating mode of oscillation. Left: observations using the SDO/HMI instrument. Right: numerical model. Sound: filtered data (269 ± 10 nHz) shifted to the audible spectrum; the sound variations inform us about the excitation and damping of the mode. © MPI

“All of these new oscillations we observe on the Sun are strongly affected by the Sun’s differential rotation”, says MPS scientist Damien Fournier. The dependence of the solar rotation with latitude determines where the modes have maximum amplitudes. “The oscillations are also sensitive to properties of the Sun’s interior: in particular to the strength of the turbulent motions and the related viscosity of the solar medium, as well as to the strength of the convective driving,” says Robert Cameron from MPS. This sensitivity is strong at the base of the convection zone, about two hundred thousand kilometers beneath the solar surface. “Just like we are using acoustic oscillations to learn about the sound speed in the solar interior with helioseismology, we can use the long-period oscillations to learn about the turbulent processes”, he adds.

“The discovery of a new type of solar oscillations is very exciting because it allows us to infer properties, such as the strength of the convective driving, which ultimately control the solar dynamo”, says Laurent Gizon. The diagnostic potential of the long-period modes will be fully realized in the coming years using a new exascale computer model being developed as part of the project WHOLESUN, supported by a European Research Council 2018 Synergy Grant.

Featured image: The east-west velocity associated with the retrograde propagating mode of oscillation. Left: observations using the SDO/HMI instrument. Right: numerical model. © MPS/Z-C Liang


Reference: Laurent Gizon et al.:Solar inertial modes: Observations, identification, and diagnostic promise, Astronomy & Astrophysics, forthcoming article Source DOI


Provided by Max Planck Institute