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Mar 2, 2024

Why are all proteins ‘left-handed’? New theory could solve origin of life mystery

Posted by in category: mathematics

Powner’s team didn’t check whether its sulfur-based catalysts had a chiral bias. That’s where Donna Blackmond, an origin of life chemist at Scripps Research, and her colleagues Min Deng and Jinhan Yu grabbed the baton. They tested two of Powner’s sulfur compounds to see whether the catalysts were sensitive to chirality as they formed dipeptides. They were, but not in the way Blackmond had expected. The catalysts created about four times as many “heterochiral” dipeptides—those pairing a left-handed amino acid (L) with a right-handed (D) one—as fully chiral products. “We thought it was bad news,” Blackmond says, because it suggested that even if amino acids on early Earth started with a bias, it would have been scrambled as proteins formed.

But as Blackmond and her colleagues looked more deeply, the news got better. In a series of experiments, the Scripps researchers started with skewed proportions of L and D amino acids—for example, 60% Ls and 40% Ds. The L, D and D, L heterochiral dipeptides formed most quickly, and as they did they pulled equal numbers of L and D amino acids out of the mix. Because of the baseline bias, eventually a predominance of Ls remained in the pool of unreacted amino acids, raising the likelihood of forming fully lefthanded dipeptides. “It’s like a domino effect,” Powner says. The first heterochiral reaction eventually encourages more homochirals to form. “And it’s a general process that works with all amino acids,” Powner says. Joyce adds: “It’s just math.”

Follow-up experiments suggested a second bias that amplifies the effect. The team found that heterochiral dipeptides precipitate out of a solution more quickly than homochiral ones, speeding the way to a relative abundance of either homochiral L, L or D, D pairs, depending the starting mix. Just why this precipitation bias occurs isn’t yet clear, Blackmond says. However, Joyce says, together with the other effect, “it beautifully fits the [experimental] data.” Blackmond adds: “The wrong answer turned out to be the right answer to get us to homochirality.”

Mar 2, 2024

StarCoder 2 and The Stack v2: The Next Generation

Posted by in category: futurism

Join the discussion on this paper page.

Mar 2, 2024

A baby star’s planet-forming disk has 3 times more water than all of Earth’s oceans

Posted by in categories: innovation, space

The team behind the breakthrough used the Atacama Large Millimeter/ submillimeter Array (ALMA) to zoom in on water vapor locked up in gas and dust within a protoplanetary disk surrounding the sun-like star HL Tauri, located 450 light-years away from Earth in the constellation Taurus.

“I had never imagined that we could capture an image of oceans of water vapor in the same region where a planet is likely forming,” Stefano Facchini research leader and an astronomer at the University of Milan, said in a statement. “Our results show how the presence of water may influence the development of a planetary system, just like it did some 4.5 billion years ago in our own solar system.”

Mar 2, 2024

How dwarf galaxies lit up the Universe after the Big Bang

Posted by in category: cosmology

Some of the faintest objects ever observed suggest that small galaxies get the credit for clearing the ‘fog’ pervading the early cosmos.

Mar 2, 2024

Scientists May Have Tamed Fusion’s #1 Nemesis

Posted by in categories: energy, innovation

A breakthrough in plasma control brings us a step closer to safe, limitless power.

Mar 2, 2024

From a year down to two weeks: Chinese scientists create efficient plant gene editing tool that leapfrogs over ‘tedious’ steps

Posted by in categories: bioengineering, biotech/medical

“Even primary school students and old farmers can master gene editing,” says [Southern University of Science and Technology, or SUSTech] scientist Zhu Jian-Kang, who has helped develop a new approach that could greatly simplify the difficult and time-consuming process of editing genes in plants.

While conventional methods of heritable gene editing in plants often take months, and in some cases up to a year, this innovative approach could reduce the process to about two weeks, according to [Cao Xuesong, a scientist at SUSTech and a member of Zhu’s team], who is also the first author of the study.

Mar 2, 2024

Neurobiologically realistic neural network enables cross-scale modeling of neural dynamics

Posted by in category: robotics/AI

Chang, YJ., Chen, YI., Yeh, HC. et al. Neurobiologically realistic neural network enables cross-scale modeling of neural dynamics. Sci Rep 14, 5,145 (2024). https://doi.org/10.1038/s41598-024-54593-w.

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Mar 2, 2024

Deterministic generation of multidimensional photonic cluster states with a single quantum emitter

Posted by in category: quantum physics

Cluster states made from multiple photons with a special entanglement structure are a useful resource for quantum technologies. Two-dimensional cluster states of microwave photons have now been deterministically generated using a superconducting circuit.

Mar 2, 2024

Scientists just created the strongest magnetic force in the universe

Posted by in categories: particle physics, space

You may never have heard of magnetars, but they are, in a nutshell an exotic type of neutron star whose magnetic field is around a trillion times stronger than the Earth’s.

To illustrate their strength, if you were to get any closer to a magnetar than about 1,000km (600 miles) away, your body would be totally destroyed.

Its unimaginably powerful field would tear electrons away from your atoms, converting you into a cloud of monatomic ions – single atoms without electrons– as EarthSkynotes.

Mar 2, 2024

Superconductivity in a van der Waals layered quasicrystal

Posted by in categories: materials, space

Recent theoretical studies36,37,38 have revealed that quasicrystalline superconductors exhibit several unconventional behaviors that are typically not observed in other known superconductors in periodic and disordered systems, thus opening a new field in the research of superconductivity. Nagai36 has studied superconducting tight-binding models of Penrose and Ammann Beenker lattices (typical two-dimensional quasicrystalline lattices) and demonstrated an intrinsic vortex pinning due to spatially inhomogeneous superconducting order parameter. Such an inhomogeneous order parameter arises from the quasicrystalline structural order, and therefore, the vortex pinning occurs without an impurity or defect. Sakai et al37. have investigated quasicrystalline superconductivity using an attractive Hubbard model on a Penrose lattice using the real-space dynamical mean-field theory. Unconventional spatially-extended Cooper pairs were formed; the sum of the momenta of the Cooper pair electrons was nonzero, in contrast to the zero total momentum of the Cooper pair in the conventional BCS superconductivity. Such a nonzero total momentum of the Cooper pair is also observed for the Fulde Ferrell Larkin Ovchinnikov (FFLO) state previously proposed for periodic systems39,40,41,42. However, the unconventional Cooper pairing in the model QC is completely different from the FFLO state because the Cooper pairing occurs under no magnetic field. In addition, under a high magnetic field, a state similar to the FFLO state is formed in the model QC38. However, this state is also different from the conventional FFLO state in periodic systems and forms a fractal-like spatial pattern of the oscillating superconducting order parameter, which is compatible with the self-similar structural order that is possessed by the QCs. As mentioned above, many interesting features are theoretically expected for superconducting QCs, which are yet to be demonstrated experimentally, and the Ta1.6 Te dodecagonal QC phase in the present study offers a precious platform for it.

In conclusion, polygrain Ta1.6 Te dodecagonal QC samples were fabricated by reaction sintering. Careful phase identification of the sample was performed by electron and powder X-ray diffraction experiments and diffraction-profile simulations. The samples were subjected to electrical resistivity, magnetic susceptibility, and specific heat measurements. The results unconditionally validate the occurrence of bulk superconductivity at a \({T}_{{{{{{\rm{c}}}}}}}\) of ~1 K. This is the first example of superconductivity in thermodynamically stable QCs. These findings are expected to motivate further investigations into the physical properties of vdW layered quasicrystals as well as two-dimensional quasicrystals. In particular, the dodecagonal QC provides a valuable platform for the experimental demonstration of the unique superconductivity theoretically predicted for QCs.

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