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Category: chemistry – Page 17

Decoding the History Recorded in Lunar Soil

A model that captures how crater-forming impacts redistribute lunar dirt will help researchers read the cosmic timeline found in samples returned from the Moon.

The Moon’s soil preserves signatures of the solar wind, cosmic rays, and episodic stellar events, but frequent meteorite strikes scramble what would otherwise be a neatly layered record of cosmic history. Researchers have now developed a mathematical model that accounts for this scrambling effect in lunar soil [1]. The model can predict the depths and concentrations of radioactive isotopes originating from astrophysical events hundreds of light-years away. It provides a guide for future lunar sampling missions that will search for evidence of specific events in our Solar System’s history.

Samples returned from the Apollo missions suggest that irradiation and the solar wind alter the lunar surface soil’s chemistry and physical appearance as it ages. In addition, nearby supernovae emit radioactive isotopes, including short-lived ones such as iron-60. Meanwhile, meteorite impacts mix all this surface material and gradually transport it deep into the soil or upward from below in a process known as impact gardening. But models of this transport often fail to capture key features observed in the Apollo samples. For example, analysis of core samples (long, vertical cylinders of soil) suggest that, in some cases, the concentrations of certain isotopes have much steeper depth dependence than models predict.

Cell biochemistry beyond membranes: Condensate physics reveals general rules for chemical responses

Basic biology courses teach that cells contain organelles—such as the nucleus, mitochondria and Golgi apparatus—set apart by lipid membranes to get things done. Recent cell biology research has revealed another organizational principle at work in cells across all orders of biology.

“Proteins and nucleic acids spontaneously organize themselves into blobs called condensates,” said Eric Dufresne, professor of physics in the College of Arts and Sciences and of materials science and engineering at Cornell Duffield College of Engineering, who is working to understand how condensates work.

Droplet-like condensates form and dissolve as cells need them, bringing selected proteins, RNA and other molecules together to coordinate biochemical reactions, said Takumi Matsuzawa, a postdoctoral researcher in physics. “Their timely formation and dissolution are essential for normal cellular function, and disruptions to this process have been linked to neurodegenerative diseases,” including Alzheimer’s and Parkinson’s.

“Entirely Surprising” — Scientists Have Found a Martian Meteorite Unlike Any Known Before

A meteorite found in Algeria has opened a rare window into nearly 2 billion years of Mars’ history that had largely been missing from the geological record.

Researchers at Boston College have determined that Northwest Africa (NWA) 13,441, a rock blasted from Mars before eventually reaching Earth, crystallized about 1.273 billion years ago. Its age places it squarely within a huge gap in the known record of shergottites, the most common type of Martian igneous meteorite. Even more unexpectedly, its chemistry points to a deep Martian source unlike any previously identified in this group.

“The characteristics of this meteorite were entirely surprising,” said Ethan Baxter, a Boston College professor of Earth and Environmental Sciences and founder of the university’s Center for Isotope Geochemistry. “No other Martian meteorite like this has an age of 1.27 billion years.”

Cells use a little-known molecule to protect themselves from iron overload

Iron is essential. Our cells need it to produce energy, carry oxygen throughout the body and power countless chemical reactions that sustain life. But this metal has a dark side. When too much of it is left free inside cells, it can trigger destructive reactions that break down DNA, proteins and even cell membranes.

Now, Whitehead Institute Member Ankur Jain, former postdoc Whitney Henry and graduate student Pushkal Sharma have discovered that cells rely on an unexpected protector against this threat: small molecules called polyamines.

The researchers’ detailed findings, published in the journal Cell, reveal that polyamines act like storage lockers for iron, safely holding the metal in a nonreactive state until cells need it.

Overlooked plant proteins may boost gut health

Plant-based diets are good for you. They promote gut, immune, metabolic and cardiovascular health, in part by cultivating a diverse community of intestinal bacteria. These benefits have long been known to stem partly from the fiber in plant-based foods, which is processed by our commensal gut bacteria, and the often brightly colored “phytochemicals” plants produce to protect themselves from environmental threats. But much remains to be learned about how exactly the bugs in our bellies process the constituents of vegetables to such salubrious effect.

A pair of studies led by Ludwig Princeton’s Jenna AbuSalim and director Joshua Rabinowitz—one in the Proceedings of the National Academy of Sciences, the other published in Nature Metabolism—shed new light on the matter.

One study reveals that plant fibers and proteins reprogram microbial metabolism to boost production of a healthful class of metabolites while suppressing that of their harmful counterparts. The other demonstrates that many physiologically important metabolites generally attributed to intestinal microbes are, in fact, also produced abundantly by mammalian metabolism.

Curiosity Mars rover discovers field of honeycomb textures

As NASA’s Curiosity rover recently began climbing a Martian valley nicknamed “Valle Grande,” it sent back images that were a familiar sight to mission scientists: honeycomb-like textures called polygonal fractures, each about 1.5–3 inches (4–8 centimeters) across. The mission has spotted small patches of these geometric shapes several times before, but nothing at the scale discovered in Valle Grande.

In a 360-degree panorama that the rover captured on June 19 and 20, the 4,930th and 4,931st Martian days, or sols, of the mission, the polygonal shapes spread in all directions for as far as the rover can see. They even wrap around the sides of a nearby butte nicknamed “Miraflores,” which stands 20 feet (6 meters) tall and is topped with a thick cap of sand.

“We’ve seen a lot of fascinating landscapes through Curiosity’s eyes, but this sea of polygons took our breath away,” said the mission’s project scientist, Ashwin Vasavada of NASA’s Jet Propulsion Laboratory in Southern California. “We measured their shapes and chemistry carefully and are hopeful there are clues in the data as to how these features formed.”

Protein-like nanoparticles sort themselves inside growing crystals, enabling controlled release

The tiny bones in your fingers withstand countless taps and swipes thanks to a precise blend of materials. Flexible collagen fibers form the framework, reinforced by hard calcium phosphate hydroxyapatite crystals. This is just one of countless examples in which living organisms weave organic materials directly into inorganic crystals with exquisite precision. In a recent study published in Nature Communications, scientists attempted to recreate such precise spatial arrangements in biomimetic composite materials.

The researchers made two types of tiny diblock copolymer nanoparticles designed to mimic pseudo-proteins. The first consisted of solid spheres about 100 nanometers big, with a poly(benzyl methacrylate) core and a shell of sulfate-containing chains tagged with a red fluorescent dye. The second consisted of hollow, bubble-like particles about 300 nanometers across. They had the same polymer core but a carboxylate-rich outer shell tagged with a green fluorescent dye.

These tiny polymer nanoparticles, engineered with different sizes and compositions, much like protein molecules, sorted themselves naturally as growing calcite crystals trapped them. Instead of mixing randomly, the two types ended up in separate regions of the crystal, creating an artificial biomineral with a distinctly organized structure—all driven by differences in the nanoparticles’ surface chemistry.

Humanity May Soon Have the Technology To Reach Other Star Systems

Tiny spacecraft riding beams of light could put humanity within reach of another star system in a single lifetime.

The recent confirmation of an atmosphere around a rocky exoplanet called LHS 1140b has created a wave of interest within the astronomy community. The planet orbits within the habitable zone around its parent star—a red dwarf located some 48 light-years from Earth.

The habitable zone is the region around the star where temperatures are just right for water to remain liquid at a planet’s surface. Astronomers detected helium being lost from the upper atmosphere of LHS 1140b. But heavier chemical compounds, such as water, which is a key ingredient for life, could exist lower in its atmosphere.

Quantum advantage reassessed: More realistic benchmarks for quantum algorithms

Quantum advantage refers to the point at which a quantum computer solves a clearly defined task faster or more efficiently than any classical computer—or makes it solvable in the first place. For many practical applications, this has not yet been demonstrated. Research therefore relies heavily on theoretical models and simulations to explore where and under what conditions such an advantage may realistically be achieved in the future.

Quantum simulation is considered a promising path toward genuine quantum advantage.

However, many existing approaches in quantum chemistry rely on simplifying assumptions: They describe molecules as closed systems perfectly isolated from their environment, model only unitary dynamics and focus on calculating ground states within the Born-Oppenheimer approximation. In nature, none of these assumptions fully hold.

Did Cellular Life Begin Twice? New Study Points to Two Independent Origins

Early metabolism may have begun as a mix of metal and enzyme catalysis before bacteria and archaea independently evolved into free-living cells.

Four billion years ago, the chemistry that eventually became life may have been unfolding around hydrothermal vents, where naturally occurring metals helped drive reactions before cells possessed the full machinery they use today. Researchers at Heinrich Heine University Düsseldorf (HHU) and collaborating institutions have reconstructed part of that transition, tracing how metabolism and enzymes changed as the ancestors of bacteria and archaea began to diverge.

The study, published in Science Advances, examined the chemical network early cells used to produce essential components of life and investigated how those reactions could have been powered. The researchers conclude that the transition to free-living bacteria and archaea may have occurred independently, even though both lineages share the same underlying genetic code.