Comment

Comment by Dr. Krishna Kumari Challa on June 3, 2022 at 12:09pm

Researchers develop nanoparticles that cross the blood-brain barrier

There are currently few good treatment options for glioblastoma, an aggressive type of brain cancer with a high fatality rate. One reason that the disease is so difficult to treat is that most chemotherapy drugs can't penetrate the blood vessels that surround the brain.

A team of  researchers is now developing drug-carrying nanoparticles that appear to get into the brain more efficiently than drugs given on their own. Using a human tissue model they designed, which accurately replicates the blood-brain barrier, the researchers showed that the particles could get into tumors and kill glioblastoma cells.

The researchers grew patient-derived glioblastoma cells in a microfluidic device. Then, they used human endothelial cells to grow blood vessels in tiny tubes surrounding the sphere of tumor cells. The model also includes pericytes and astrocytes, two cell types that are involved in transporting molecules across the blood-brain barrier.

Joelle P. Straehla et al, A predictive microfluidic model of human glioblastoma to assess trafficking of blood–brain barrier-penetrant nanoparticles, Proceedings of the National Academy of Sciences (2022). DOI: 10.1073/pnas.2118697119

Cynthia Hajal et al, Engineered human blood–brain barrier microfluidic model for vascular permeability analyses, Nature Protocols (2022). DOI: 10.1038/s41596-021-00635-w

Comment by Dr. Krishna Kumari Challa on June 3, 2022 at 11:15am

Time crystals 'impossible' but obey quantum physics

Time crystals: First theorized in 2012 by Nobel Laureate Frank Wilczek and identified in 2016, time crystals exhibit the bizarre property of being in constant, repeating motion in time despite no external input. Their atoms are constantly oscillating, spinning, or moving first in one direction, and then the other.

Time crystals are different from a standard crystal—like metals or rocks—which is composed of atoms arranged in a regularly repeating pattern in space.

Scientists have created the first "time-crystal" two-body system in an experiment that seems to bend the laws of physics. It comes after the same team recently witnessed the first interaction of the new phase of matter.

Time crystals were long believed to be impossible because they are made from atoms  in never-ending motion. The discovery, published in Nature Communications, shows that not only can time crystals be created, but they have potential to be turned into useful devices.

Everybody knows that perpetual motion  machines are impossible. However, in quantum physics perpetual motion is okay as long as we keep our eyes closed. By sneaking through this crack we can make time crystals. It turns out putting two of them together works beautifully, even if time crystals should not exist in the first place. And we already know they also exist at room temperature.

A "two-level system" is a basic building block of a quantum computer. Time crystals could be used to build quantum devices that work at room temperature. 

An international team of researchers observed time crystals by using Helium-3 which is a rare isotope of helium with one missing neutron. The experiment was carried out in Aalto University.

They cooled superfluid helium-3 to about one ten thousandth of a degree from absolute zero (0.0001 K or -273.15 C). The researchers created two time crystals inside the superfluid, and brought them to touch. The scientists then watched the two time crystals interacting as described by quantum physics.

Nonlinear two-level dynamics of quantum time crystals, Nature Communications (2022). DOI: 10.1038/s41467-022-30783-w

Comment by Dr. Krishna Kumari Challa on June 2, 2022 at 6:48am

The brain’s immunological wonderland

Researchers once thought that the brain was walled off from the rest of the body’s immune system, but an exciting picture is emerging of the brain as a unique immunologi.... The brain’s border control actually does allow immune cells from the body into the fluid-filled membranes that surround the organ, which are an “immunological wonderland”, says neuroimmunologist Kiavash Movahedi. Special immune cells produced in the skull’s bone marrow could be gentler than normal immune cells. Researchers are exploring how these and other kinds of immune cells in the brain play a role in fighting diseases and could be harnessed in treatments.

Comment by Dr. Krishna Kumari Challa on June 2, 2022 at 6:30am

Capturing carbon with crops, trees and bioenergy

An integrated approach to land management practices in the U.S. can reduce carbon dioxide in the atmosphere far more than earlier estimates based on separate approaches, Michigan State University researchers say. Their research was published May 31 in the journal Global Change Biology.

--

Automated drones could scare birds off agricultural fields

In the future, cameras could spot blackbirds feeding on grapes in a vineyard and launch drones to drive off the avian irritants, then return to watch for the next invading flock. All without a human nearby.

--

Physicists demonstrate novel mechanism that can prevent light waves...

In collaboration with the group of Professor Mordechai Segev (Technion, Israel Institute of Technology), physicists from the group of Professor Alexander Szameit (University of Rostock) have demonstrated a novel type of mechanism that can prevent light waves from spreading freely. So far, the underlying physical effect had been considered far too weak to fully arrest wave expansion. In their recent experiments, the physicists observed that such light localization is nevertheless possible, demonstrating the uncanny sensitivity of wave propagation across a wide range of spatial length scales. Their discovery was recently published in the journal Science Advances.

--

Less air pollution leads to higher crop yields, study shows

Usually, increasing agricultural productivity depends on adding something, such as fertilizer or water. A new Stanford University-led study reveals that removing one thing in particular—a common air pollutant—could lead to dramatic gains in crop yields. The analysis, published June 1 in Science Advances, uses satellite images to reveal for the first time how nitrogen oxides—gases found in car exhaust and industrial emissions—affect crop productivity. Its findings have important implications for increasing agricultural output and analyzing climate change mitigation costs and benefits around the world.

Comment by Dr. Krishna Kumari Challa on June 2, 2022 at 6:20am

Comment by Dr. Krishna Kumari Challa on June 2, 2022 at 6:15am

How electric fish were able to evolve electric organs

Electric organs help electric fish, such as the electric eel, do all sorts of amazing things: They send and receive signals that are akin to bird songs, helping them to recognize other electric fish by species, sex and even individual. A new study in Science Advances explains how small genetic changes enabled electric fish to evolve electric organs. The finding might also help scientists pinpoint the genetic mutations behind some human diseases.

Evolution took advantage of a quirk of fish genetics to develop electric organs. All fish have duplicate versions of the same gene that produces tiny muscle motors, called sodium channels. To evolve electric organs, electric fish turned off one duplicate of the sodium channel gene in muscles and turned it on in other cells. The tiny motors that typically make muscles contract were repurposed to generate electric signals, and voila! A new organ with some astonishing capabilities was born.

In the new paper, researchers  describe discovering a short section of this sodium channel gene—about 20 letters long—that controls whether the gene is expressed in any given cell. They confirmed that in electric fish, this control region is either altered or entirely missing. And that's why one of the two sodium channel genes is turned off in the muscles of electric fish. But the implications go far beyond the evolution of electric fish.

This control region is in most vertebrates, including humans. So, the next step in terms of human health would be to examine this region in databases of human genes to see how much variation there is in normal people and whether some deletions or mutations in this region could lead to a lowered expression of sodium channels, which might result in disease. 

Sarah LaPotin et al, Divergent cis-regulatory evolution underlies the convergent loss of sodium channel expression in electric fish, Science Advances (2022). DOI: 10.1126/sciadv.abm2970. www.science.org/doi/10.1126/sciadv.abm2970

Comment by Dr. Krishna Kumari Challa on June 2, 2022 at 6:09am

Bacteria-killing nano-drills : Visible light triggers molecular machines to treat infections

Molecular machines that kill infectious bacteria have been taught to see their mission in a new light.

The latest iteration of nanoscale drills developed by researchers are activated by visible light rather than ultraviolet (UV), as in earlier versions. These have also proven effective at killing bacteria through tests on real infections.

Six variants of molecular machines were successfully tested by  chemists. All of them punched holes in the membranes of gram-negative and gram positive bacteria in as little as two minutes. Resistance was futile for bacteria that have no natural defenses against mechanical invaders. That means they are unlikely to develop resistance, potentially offering a strategy to defeat bacteria that have become immune to standard antibacterial treatments over time.

The new version gets its energy from still-blueish light at 405 nanometers, spinning the molecules' rotors at 2 to 3 million times per second.

It's been suggested by other researchers that light at that wavelength has mild antibacterial properties of its own, but the addition of molecular machines supercharges it. Bacterial infections like those suffered by burn victims and people with gangrene will be early targets.

The researchers also found the machines effectively break up biofilms and persister cells, which become dormant to avoid antibacterial drugs.

The new machines also promise to revive antibacterial drugs considered ineffective. Drilling through the microorganisms' membranes allows otherwise ineffective drugs to enter cells and overcome the bug's intrinsic or acquired resistance to antibiotics. 

Ana L. Santos et al, Light-activated molecular machines are fast-acting broad-spectrum antibacterials that target the membrane, Science Advances (2022). DOI: 10.1126/sciadv.abm2055. www.science.org/doi/10.1126/sciadv.abm2055

Comment by Dr. Krishna Kumari Challa on June 2, 2022 at 5:55am

How the brain responds to surprising events

When your brain needs you to pay attention to something important, one way it can do that is to send out a burst of noradrenaline, according to a new  study.

This neuromodulator, produced by a structure deep in the brain called the locus coeruleus, can have widespread effects throughout the brain. In a study of mice, the MIT team found that one key role of noradrenaline, also known as norepinephrine, is to help the brain learn from surprising outcomes.

Noradrenaline is one of several neuromodulators that influence the brain, along with dopamine, serotonin, and acetylcholine. Unlike neurotransmitters, which enable cell-to-cell communication, neuromodulators are released over large swathes of the brain, allowing them to exert more general effects.

Neuromodulatory substances are thought to perfuse large areas of the brain and thereby alter the excitatory or inhibitory drive that neurons are receiving in a more point-to-point fashion. This suggests they must have very crucial brain-wide functions that are important for survival and for brain state regulation.

The researchers also found that the neurons that generate this noradrenaline signal appear to send most of their output to the motor cortex, which offers more evidence that this signal stimulates the animals to take action.

 Noradrenaline has been linked to arousal and boosting alertness, but too much noradrenaline can lead to anxiety.

This work shows that the locus coeruleus encodes unexpected events, and paying attention to those surprising events is crucial for the brain to take stock of its environment. 

In addition to its role in signaling surprise, the researchers also discovered that noradrenaline helps to stimulate behavior that leads to a reward, particularly in situations where there is uncertainty over whether a reward will be offered.

Mriganka Sur, Spatiotemporal dynamics of noradrenaline during learned behaviour, Nature (2022). DOI: 10.1038/s41586-022-04782-2. www.nature.com/articles/s41586-022-04782-2

Comment by Dr. Krishna Kumari Challa on June 1, 2022 at 8:56am

World’s largest organism found in Australia

Single hybrid seagrass plant now stretches across 180 kilometers

Two closely related species hybridize and create a superorganism whose growth and expansion seems unstoppable. That’s what’s happened in Western Australia’s Shark Bay, researchers say, where a seagrass meadow (see above) stemming from a single hybrid plant has extended its reach across more than 180 kilometers—an area the size of Washington, D.C. Two years ago, scientists discovered some of the seagrass there was a clone of a Poseidon’s ribbon weed (Posidonia australis) that had 40 chromosomes instead of the typical 20. They think half those chromosomes may come from the ribbon weed and half from an unknown species. That second half appears to have provided a big survival advantage, as this hybrid has taken over all but one of the 10 seagrass meadows surveyed, the scientists report today in the Proceedings of the Royal Society B. The clone is about 1.5 orders of magnitude larger than the largest fungi and the longest sea animal. The team suspects the clone arose 4500 years ago and has been spreading ever since. That would make it among the oldest organisms on Earth, although not quite as old as the oldest tree. Shark Bay is at the northern edge of where this seagrass can survive, and global warming is making it harder for the plants to hang on there. Low rainfall and high evaporation rates have also caused the water to become much saltier. The clone’s extra genes may be providing a way for it to adapt to these stresses, the authors note.

https://www.science.org/content/article/world-s-largest-organism-fo...

Comment by Dr. Krishna Kumari Challa on June 1, 2022 at 8:52am

How wingless salamanders fly

From frogs remaining airborne using their webbed feet to lizards and snakes gliding by expanding their ribcages, biologists might have thought they had seen every unusual aerial strategy — but now they report flying salamanders.

https://www.nature.com/articles/d41586-022-01375-x

• ‹ Previous
• 1
• …
• 572
• 573
• 574
• 575
• 576
• …
• 1163
• Next ›
• Page