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Category: biotech/medical – Page 213

Magnetic Field Maneuvers Magnetite Monolayers

Suppose you want to make a tiny robot to perform surgery inside a human patient. To avoid damaging healthy tissue and to squeeze into tight spots, the robot should be squishy. And manipulating the robot’s movements with magnetic fields would make sense, as tissues don’t respond to magnetism. But what material would you use for the robot’s limbs? Magnetic materials are stiff and brittle. Embedding tiny particles of them in a rubbery matrix could work, but the thinner—and therefore bendier—you make the composite material, the less it responds to a magnetic field. Heinrich Jaeger of the University of Chicago, Monica Olvera de la Cruz of Northwestern University, Illinois, and their collaborators have now overcome that obstacle by making thin, flexible sheets out of self-assembled nanoparticles of magnetite [1]. Even a modest field of 100 milliteslas can lift a sheet and bend it by 50°, they found.

At room temperature, magnetite (Fe3O4) is ferrimagnetic—that is, the magnetic moments in its two sublattices align in opposite directions but with unequal magnitudes, yielding a net magnetization. The smaller a ferrimagnet, the greater the chance that it has a single domain, and therefore the lower the temperature at which the domain’s magnetization will flip. When the sample size gets down to a few tens of nanometers, a ferrimagnet made of randomly flipping particles becomes, in effect, a paramagnet—that is, it lacks a net magnetization and is attracted by an applied magnetic field. The attraction can be strong. The discoverers of this phenomenon in 1959 dubbed it superparamagnetism [2].

The researchers realized that a sheet made from a single layer of superparamagnetic particles could serve as a viable material for the magnetic actuation of small soft robots. To create the layers, they suspended magnetite nanoparticles in droplets of water coated with an organic solvent. The solvent attracted the nanoparticles, which migrated to a droplet’s surface. The water slowly evaporated, leaving behind a layer of closely packed nanoparticles draped on the droplet’s support structure, a square copper grid. Each of the 20 × 20 µm squares supported a single sheet. As shown in the figure, some of the sheets happened to have a single unattached corner.

Virtual reality research shows how temporary anxiety can affect learning

A brief episode of anxiety may have a bigger influence on a person’s ability to learn what is safe and what is not. Research recently published in npj Science of Learning has used a virtual reality game that involved picking flowers with bees in some of the blossoms that would sting the participant—simulated by a mild electrical stimulation on the hand.

Researchers worked with 70 neurotypical participants between the ages of 20 and 30. Claire Marino, a research assistant in the ZVR Lab, and Pavel Rjabtsenkov, a Neuroscience graduate student at the University of Rochester School of Medicine and Dentistry, were co-first authors of the study.

Their team found that the people who learned to distinguish between the safe and dangerous areas—where the bees were and were not—showed better spatial memory and had lower , while participants who did not learn the different areas had higher anxiety and heightened fear even in safe areas.

Genomic study maps nearly 60 million years of apple genus evolution and diversity

A new comparison and analysis of the genomes of species in the genus Malus, which includes the domesticated apple and its wild relatives, revealed the evolutionary relationships among the species and how their genomes have evolved over the past nearly 60 million years.

The research team identified structural variations among the genomes and developed methods for identifying genes associated with desirable traits, like tastiness and resistance to disease and cold, that could help guide future breeding programs.

A paper describing the research, conducted by an international team that includes Penn State biologists, was published in the journal Nature Genetics.

Variation in exhaled droplet characteristics may explain why some people are disease ‘superspreaders’

A team of infectious disease specialists and environmental engineers at Université Claude Bernard Lyon’s, École Centrale de Lyon, in France, and the University of Rome La Sapienza, in Italy, has found via experiments that the physical characteristics of exhaled droplets play a role in the transmission of infectious diseases.

In their study published in the journal Physical Review Fluids, the group asked volunteers to breathe normally while silent, to speak normally, and to cough, while their exhausted droplet characteristics were measured.

Prior research has shown that many are spread via tiny expelled through the nose and mouth of infected people as they breathe. These droplets are small enough to hang in the air long enough for others to inhale them, leading to infection. Prior research has also shown that some people can be characterized as superspreaders—for some reason, they infect more people than do others. Some suspect that this might be due to the size of droplets expelled by superspreaders or the distance the droplets travel once expelled.

Brain-machine interface study reveals how intentions and actions are linked in time

Researchers led by Jean-Paul Noel at the University of Minnesota, United States, have decoupled intentions, actions and their effects by manipulating the brain-machine interface that allows a person with otherwise paralyzed arms and legs to squeeze a ball when they want to.

Published in the open-access journal PLOS Biology, the study reveals temporal binding between and actions, which makes actions seem to happen faster when they are intentional.

Separating intentions from actions was made possible because of a . The participant was paralyzed with damage to their C4/C5 vertebrae and had 96 electrodes implanted in the region of their motor cortex.

Iron and blue light enable rapid, low-toxicity creation of carbohydrates for new antibiotics

Researchers at the University of Oklahoma have made a discovery that could potentially revolutionize treatments for antibiotic-resistant infections, cancer and other challenging gram-negative pathogens without relying on precious metals.

Currently, precious metals like platinum and rhodium are used to create synthetic carbohydrates, which are vital components of many approved antibiotics used to combat , including Pseudomonas aeruginosa, a notorious hospital-acquired infection responsible for the deaths of immunocompromised patients. However, these elements require harsh reaction conditions, are expensive to use and are harmful to the environment when mined.

In an innovative study published in the journal Nature Communications, an OU team led by Professor Indrajeet Sharma has replaced these with either blue light or iron, achieving similar results with significantly lower toxicity, reduced costs, and greater appeal for researchers and .

The Interplay between KSHV Infection and DNA-Sensing Pathways

During viral infection, the innate immune system utilizes a variety of specific intracellular sensors to detect virus-derived nucleic acids and activate a series of cellular signaling cascades that produce type I IFNs and proinflammatory cytokines and chemokines. Kaposi’s sarcoma-associated herpesvirus (KSHV) is an oncogenic double-stranded DNA virus that has been associated with a variety of human malignancies, including Kaposi’s sarcoma, primary effusion lymphoma, and multicentric Castleman disease. Infection with KSHV activates various DNA sensors, including cGAS, STING, IFI16, and DExD/H-box helicases. Activation of these DNA sensors induces the innate immune response to antagonize the virus. To counteract this, KSHV has developed countless strategies to evade or inhibit DNA sensing and facilitate its own infection. This review summarizes the major DNA-triggered sensing signaling pathways and details the current knowledge of DNA-sensing mechanisms involved in KSHV infection, as well as how KSHV evades antiviral signaling pathways to successfully establish latent infection and undergo lytic reactivation.

DNA repair mechanism may hold key to overcoming tumor resistance to radiotherapy

A research team has unveiled a crucial mechanism that helps regulate DNA damage repair, with important implications for improving cancer treatment outcomes.

The result was published in Cell Death & Differentiation. The team was led by Professor Zhao Guoping at the Hefei Institutes of Physical Science of the Chinese Academy of Sciences.

The efficacy of radiotherapy is largely limited by the DNA damage repair capacity of tumor cells. When ionizing radiation induces DNA double-strand breaks—the primary lethal damage—tumor cells often exhibit abnormal overexpression of DNA repair proteins, establishing a robust damage response system that drives clinical radioresistance. To address this challenge, the team deciphered the regulatory network of epigenetic modifications in DNA damage repair.

The Race to Explain Why More Young Adults Are Getting Cancer

But classic risk factors do not seem to fully explain the recent rise in early-onset cancers, says Dr. Cathy Eng, director of the Young Adult Cancers Program at Vanderbilt University’s Ingram Cancer Center in Tennessee. Some of the trends are baffling; young, nonsmoking women, for example, are being diagnosed with lung cancer in strangely high numbers. Many times, Eng’s patients were extremely healthy: vegetarians, marathon runners, avid swimmers. “That’s why I really believe there’s other risk factors to account for this,” she says.

There’s no shortage of theories about what those may be. Many scientists point to modern diets, which tend to be heavy on potentially carcinogenic products—including ultra-processed foods, red meat, and alcohol—and may also contribute to weight gain, another cancer risk factor. The foods we eat can also affect the gut microbiome, the colony of microbes that lives in the digestive system and appears linked to overall health. Alterations to the gut microbiome via diet, or perhaps exposure to drugs like antibiotics, have also been implicated.

Other researchers blame the microplastics littering our environment and leaching into our food and water supplies, some of which, according to a 2024 study, have even shown up in cancer patients’ tumors. Other environmental factors could also be to blame, given that everything from cosmetics to food packaging contains substances that many researchers aren’t convinced are safe. Even our near constant exposure to artificial light could be messing with normal biological rhythms in ways that have profound health consequences, some research suggests.

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