Gold may hold the key to unlocking an elusive but highly desirable reaction pathway.


A new Australian-led stud finds gold atoms could be key to unlocking organic reactions.

Organic molecules are the building blocks for materials we use every day - from our clothes and coffee cups to the screen displays of our phones. Controlling reactions of these organic molecules is the key to designing materials with functional properties.

Reactions targeting carbon-hydrogen (C-H) bonds have long been of scientific interest given that almost all organic molecules contain these bonds. Led by FLEET at Monash University, a new study (published this week in the Journal of the American Chemical Society) finds that individual gold atoms may provide a low energy route for reactions which can target specific C-H bonds.

THE "HOLY GRAIL" OF CHEMICAL REACTIONS

"One of FLEET's goals is the development of materials whose electronic properties may be exploited in low-energy technologies," says corresponding author A/Prof Agustin Schiffrin.

Organic molecules may serve as useful building blocks for tuneable construction of these materials, provided reactions between molecules can be controlled at the atomic scale.

Carbon-hydrogen bonds are among the most common bonds in organic molecules. Because of this, the ability to target specific C-H bonds in chemical reactions has been described by some researchers as the "holy grail". Unfortunately, two big challenges stand in the way of C-H activation reactions:

1. Difficulty in targeting only one specific bond for reaction (poor selectivity).
2. A lot of energy is required to break these bonds (high activation energy).

Leprosy is one of the world's oldest and most persistent diseases but the bacteria that cause it may also have the surprising ability to grow and regenerate a vital organ.
Scientists have discovered that parasites associated with leprosy can reprogramme cells to increase the size of a liver in adult animals without causing damage, scarring or tumors.

The findings suggest the possibility of adapting this natural process to renew ageing livers and increase healthspan - the length of time living disease-free - in humans.

Experts say it could also help regrow damaged livers, thereby reducing the need for transplantation, which is currently the only curative option for people with end-stage scarred livers.

Cellular reprogramming

Previous studies promoted the regrowth of mouse livers by generating stem cells and progenitor cells - the step after a stem cell that can become any type of cell for a specific organ - via an invasive technique that often resulted in scarring and tumour growth.

To overcome these harmful side-effects, Edinburgh researchers built on their previous discovery of the partial cellular reprogramming ability of the leprosy-causing bacteria, Mycobacterium leprae.

Working with the US Department of Health and Human Services in Baton Rouge, Louisiana, the team infected 57 armadillos - a natural host of leprosy bacteria - with the parasite and compared their livers with those of uninfected armadillos and those that were found to be resistant to infection.

They found that the infected animals developed enlarged - yet healthy and unharmed - livers with the same vital components, such as blood vessels, bile ducts and functional units known as lobules, as the uninfected and resistant armadillos.

Albert Einstein's theory of general relativity has been remarkably successful in describing the gravity of stars and planets, but it doesn't seem to apply perfectly on all scales.

Everything in the universe has gravity - and feels it too. Yet this most common of all fundamental forces is also the one that presents the biggest challenges to physicists. Albert Einstein's theory of general relativity has been remarkably successful in describing the gravity of stars and planets, but it doesn't seem to apply perfectly on all scales.

General relativity has passed many years of observational tests, from Eddington's measurement (opens in new tab) of the deflection of starlight by the Sun in 1919 to the recent detection of gravitational waves. However, gaps in our understanding start to appear when we try to apply it to extremely small distances, where the laws of quantum mechanics operate, or when we try to describe the entire universe.

Our new study, published in Nature Astronomy, has now tested Einstein's theory on the largest of scales. We believe our approach may one day help resolve some of the biggest mysteries in cosmology, and the results hint that the theory of general relativity may need to be tweaked on this scale.

A fossil discovered in Canada could be a rare finding of an entire dinosaur skeleton complete with fossilised skin.

The exposed fossil of the hadrosaur, a large-bodied, herbivorous, duck-billed dinosaur, is protruding from a hillside in Dinosaur Provincial Park in Alberta, Canada, which is one of the world's richest locations for dinosaur fossils.

The fossil includes a large portion of the animal's tail and its right hind foot, and is oriented in a way that suggests the entire skeleton may still be preserved within the hill. Whole skeletons are very rare, so this exceptional "dinosaur mummy" is likely to provide important insights about the animal's appearance and overall anatomy.

After shocking the mathematics community with a major result in 2013, Yitang Zhang now says he has solved an analogue of the celebrated Riemann hypothesis.
A mathematician who went from obscurity to luminary status in 2013 for cracking a century-old question about prime numbers now claims to have solved another. The problem is similar to — but distinct from — the Riemann hypothesis, which is considered one of the most important problems in mathematics.

Number theorist Yitang Zhang, who is based at the University of California, Santa Barbara, posted his proposed solution — a 111-page preprint — on the arXiv preprint server on 4 November¹. It has not yet been validated by his peers. But if it checks out, it will go some way towards taming the randomness of prime numbers, whole numbers that cannot be divided evenly by any number except themselves or 1.

The Landau-Siegel zeros conjecture is similar to — and, some suspect, less challenging than — the Riemann hypothesis, another question on the randomness of primes and one of the biggest unsolved mysteries in mathematics. Although it has been known for millennia that there are infinitely many prime numbers, there is no way to predict whether a given number will be prime; only the probability that it will be, given its size. Solving either the Riemann or Landau-Siegel problems would mean that the distribution of prime numbers does not have huge statistical fluctuations.

"For me in the field, this result would be massive," says Andrew Granville, a number theorist at the University of Montreal in Canada. But he warns that others, including Zhang, have previously proposed solutions that turned out to be faulty, and that it will take a while for researchers to comb through Zhang's argument to see if it is correct. "Right now, we're very far from being certain."

Zhang did not respond to Nature's requests for comment. But he did write about his latest work on the Chinese website Zhihu. "As for the Landau-Siegel zeros conjecture, I didn't think about giving up," he wrote. He added: "As for my planning of the future, I won't give away these math problems. I think I probably have to do mathematics all my life. I don't know what to do without doing mathematics. People have asked questions about my retirement. I've said that if I leave math, I really won't know how to live." (His comments were translated into English by the website Pandaily.)

A pilot flying an Airbus from Miami to Denver during Hurricane Ian witnessed an extraordinary weather phenomenon known as 'St Elmo's Fire' that appeared as purple lightning shooting through the night sky.

The spectacular show occurs during thunderstorms when the atmosphere becomes charged and an electrical discharge of plasma is created between an object and the air around it.

Luis Andress, the captain of the plane, recently shared the experience, noting it was the first time he has ever seen St Elmo's fire with such 'intensity.'

Hurricane Ian, which hit Florida on September 28, clocked in as a Category 4 when it made landfall and was the deadliest the state has seen since 1935's Labor Day hurricane.

A team of physicists say they managed to create a new phase of matter by shooting laser pulses reading out the Fibonacci sequence to a quantum computer in Colorado. The matter phase relies on a quirk of the Fibonacci sequence to remain in a quantum state for longer.

Just as ordinary matter can be in a solid, liquid, gas, or superheated plasmic phase (or state), quantum materials also have phases. The phase refers to how the matter is structured on an atomic level — the arrangement of its atoms or its electrons, for example. Several years ago, physicists discovered a quantum supersolid, and last year, a team confirmed the existence of quantum spin liquids, a long-suspected phase of quantum matter, in a simulator. The recent team thinks they've discovered another new phase.

Quantum bits, or qubits, are like ordinary computer bits in that their values can be 0 or 1, but they can also be 0 or 1 simultaneously, a state of ambiguity that allows the computers to consider many possible solutions to a problem much faster than an ordinary computer. Quantum computers should eventually be able to solve problems that classical computers can't.

A new study comparing the biodiversity of wild mammals in Europe 8,000 years ago with the present has found that more species have been gained than lost on the continent.

The study, published in Global Change Biology and led by the University of York, found that recent species recovery and the introduction of non-native species has increased diversity by equivalent or greater amounts in many European regions, despite loss of habitat and local extinctions in many areas.

In cognitive tests for recognizing certain types of patterns, crows outperformed monkeys.
Crows are notoriously clever — the songbirds can use tools, understand the concept of zero and follow basic analogies. Now, a new study suggests that their grasp of one complex cognitive principle in particular is better than that of monkeys and comparable to that of small children.

Researchers found that crows can distinguish paired elements buried in larger sequences, a cognitive ability known as recursion. Consider the sentence: "The cat the dog chased meowed." Although the sentence is admittedly a grammatical nightmare, most adults would quickly understand that the cat meowed and that the dog chased the cat. This capacity to pair elements like "cat" to "meow" and "dog" to "chase" in a sentence, or any sequence, was once thought to be a uniquely human trait.

The new study, however, suggests that crows can do it too. And this latest research builds on previous work demonstrating the existence of recursive reasoning among monkeys. "One of the most distinguishing features of human communicative cognition may turn out not to be that human-specific after all," lead author Diana A. Liao, a postdoctoral candidate at the University of Tübingen in Germany, told Live Science in an email.

Grammar isn't the only place where recursion occurs. Our ears can distinguish a musical phrase within a larger piece, and our minds can set aside a mathematical expression embedded between parentheses. Indeed, a 2020 study published in the journal Science Advances demonstrated that people can follow recursive patterns even without a formal background in reading and mathematics. In that study, people from isolated Amazonian tribes identified recursive patterns about as well as adults living in the U.S. did. Nonhuman primates also demonstrated an ability to understand recursion; the same study found that rhesus monkeys (Macaca mulatta) were only slightly inferior to toddlers when it came to distinguishing paired elements, such as opened and closed brackets, from a morass of symbols.

The new study, published Nov. 2 in Science Advances, builds on this work to extend the findings beyond primates. "The study is well-designed and executed, and the results are clear and compelling," said Stephen Ferrigno, an assistant professor in the psychology department at the University of Wisconsin-Madison and lead author on the 2020 paper. Ferrigno was not involved in the new study.

A signature in the X-ray light emitted by a highly magnetised dead star known as a magnetar suggests the star has a solid surface with no atmosphere, according to a new study by an international collaboration co-led by UCL researchers.
The study, published in the journal Science, uses data from a NASA satellite, the Imaging X-ray Polarimetry Explorer (IXPE), which was launched last December. The satellite, a collaboration between NASA and the Italian Space Agency, provides a new way of looking at X-ray light in space by measuring its polarisation - the direction of the light waves' wiggle.

The team looked at IXPE's observation of magnetar 4U 0142+61, located in the Cassiopeia constellation, about 13,000 light years away from Earth. This was the first time polarised X-ray light from a magnetar had been observed.

Magnetars are neutron stars - very dense remnant cores of massive stars that have exploded as supernovae at the ends of their lives. Unlike other neutron stars, they have an immense magnetic field - the most powerful in the universe. They emit bright X-rays and show erratic periods of activity, with the emission of bursts and flares which can release in just one second an amount of energy millions of times greater than our Sun emits in one year. They are believed to be powered by their ultra-powerful magnetic fields, 100 to 1,000 times stronger than standard neutron stars.