Powerful magnetic field leaves imprint on nuclear matter

Also, a synthetic human antibody takes us closer to a solution against snake venoms, and using light to tackle antibiotic resistance in bacteria.

Published : Mar 07, 2024 11:00 IST - 5 MINS READ

Heavy ion collisions that are off-centre produce a quark–gluon plasma along with a strong magnetic field, allowing researchers to study the interactions between the two.

Heavy ion collisions that are off-centre produce a quark–gluon plasma along with a strong magnetic field, allowing researchers to study the interactions between the two. | Photo Credit: Tiffany Bowman and Jen Abramowitz/Brookhaven National Laboratory

A new analysis by the STAR collaboration at the Relativistic Heavy Ion Collider, a particle collider at the Brookhaven National Laboratory (BNL) provides the first direct evidence of what may be the imprint of the universe’s most powerful magnetic fields on “deconfined” nuclear matter.

Collisions of heavy ions briefly produced a magnetic field 1018, or a billion billion, times stronger than the earth’s and 10,000 times stronger than a neutron star’s, and it left observable effects. The evidence is from measuring the way differently charged particles produced in the collisions separated.

The data show that powerful magnetic fields generated in off-centre collisions induce an electric current in quarks and gluons as they get freed, or deconfined, from protons and neutrons by the particle smash-ups. The findings provide a new way to study the electrical conductivity of this “quark-gluon plasma (QGP)”, as this soup of quarks and gluons is called, and also understand more about the strong nuclear force that binds all these particles together inside nuclei.

“This is probably the strongest magnetic field in our universe,” said Gang Wang, a STAR physicist from the University of California, Los Angeles. The work was published in a recent issue of Physical Review X.

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Because things happen very quickly in heavy ion collisions, the field does not last long, dissipating in less than 10-23 sec, or 10 millionths of a billionth of a billionth of a second, which makes it difficult to observe. So instead of trying to measure the field directly, the STAR scientists looked for evidence of its impact on the particles streaming out of the collisions.

“This is the first measurement of how the magnetic field interacts with the QGP,” said Diyu Shen, a STAR physicist from Fudan University. In fact, measuring the impact of that interaction provides direct evidence that these powerful magnetic fields exist.

It is well known that magnetic fields can affect the movement of charged particles and even induce electromagnetic fields in materials that conduct electricity, such as metals. It is the same here but on a much smaller scale. “We wanted to see if the charged particles generated in off-centre heavy ion collisions were being deflected in a way that could only be explained by the existence of an electromagnetic field in the tiny specks of QGP created in these collisions,” said Aihong Tang of BNL. “In the end, we see a pattern of charge-dependent deflection that can only be triggered by an electromagnetic field in the QGP.”

Synthetic antibody neutralises snakebite toxin

A spectacled cobra.

A spectacled cobra. | Photo Credit: Kartik Sunagar, CES, IISc

Scientists at Scripps Research, US, and the Evolutionary Venomics Lab (EVL) at the Centre for Ecological Sciences (CES), Indian Institute of Science (IISc), Bengaluru, have developed a synthetic human antibody that can neutralise a potent neurotoxin produced by the Elapidae family of highly venomous snakes, which includes the cobra.

To synthesise the new antibody, the team employed the same approach used to screen for antibodies against HIV and COVID-19. “This is the first time that this particular strategy is being applied to develop antibodies for snakebite treatment,” said Senji Laxme of the EVL, the first author of the study. The study has been published in Science Translational Medicine.

According to an IISc press release, this development takes us a step closer to a universal antibody solution for broad protection against a variety of snake venoms.

The current strategy for developing antivenoms involves injecting snake venom into equines and collecting antibodies from their blood. “These animals get exposed to various bacteria and viruses,,” explained Kartik Sunagar of CES. “As a result, antivenoms also include antibodies against microorganisms, which are therapeutically redundant.” The IISc team’s antibody targets a conserved region found in the disulphide core of a major toxin called the three-finger toxin (3FTx) in the elapid venom.

A large library of artificial antibodies from humans thus designed was displayed on yeast cell surfaces. These antibodies were tested for their ability to bind to 3FTxs from various elapid snakes around the world. After repeated screening of the 149 variants of 3FTxs in public repositories, they narrowed down their choice to one antibody that could bind strongly to 99 3FTxs.

In one set of experiments that tested the antibody in animal models, the scientists used a 3FTx from the Taiwanese banded krait. When it was injected into mice, it killed them within four hours. But those that were given the toxin premixed with the synthetic antibody survived past the 24-hour observation window and looked completely healthy. The efficacy of the antibody was found to be nearly 15 times that of the conventional antivenom.

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The researchers used human-derived cell lines to produce the antibody, bypassing the need to inject the venom first into animals. “This solves two problems at the same time,” said Sunagar. “First, it is an entirely human antibody and, hence, side effects, including fatal anaphylaxis, occasionally observed in patients being treated with conventional antivenom, can be prevented. Secondly, this would mean that animals need not be harmed in future to produce this life-saving antidote.”

Using light to crack antibiotic resistance

Antibiotic-resistant Staphylococcus aureas bacteria can become susceptible to antibiotics after treatment with light-activated dye molecules.

Antibiotic-resistant Staphylococcus aureas bacteria can become susceptible to antibiotics after treatment with light-activated dye molecules. | Photo Credit: J. Haney Carr/Public Health Image Library, Centers for Disease Control, US

Antibiotic resistance is a rapidly growing global health problem. If the current trend continues, epidemiologists predict that the number of people infected by antibiotic- resistant bacteria will reach 225 million worldwide by 2030.

A costly way of fighting antibiotic resistance is to develop new drugs. Another route, which is gaining popularity, is to inhibit antibiotic-eluding mechanisms that bacteria develop as they evolve. This can be achieved using light, a process called photodynamics. This is the route a team of scientists at the University of São Paulo, led by Vanderlei Bagnato, took. “We’re using photodynamics to reverse resistance so that antibiotics can act again,” he said. The scientists’ approach reduces the persistence of antibiotic resistance in a Staphylococcus bacterium and involves introducing into a bacterium dyes that produce reactive oxygen after absorbing light. This oxygen oxidises and destroys structures within the bacterium that are linked to antibiotic resistance without killing the organism. The work was presented at the recent SPIE Photonics West 2024 conference in San Francisco.

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