Researchers from the Institute for Molecules and Materials at Radboud University, Netherlands, have demonstrated that a complex self-organizing chemical reaction network can perform various computational tasks, such as nonlinear classification and complex dynamics prediction.
Once upon a time, Earth was barren. Everything changed when, somehow, out of the chemistry available early in our planet’s history, something started squirming – processing available matter to survive, to breed, to thrive.
What that something was, and when it first squirmed, have been burning questions that have puzzled humanity probably for as long as we’ve been able to ask “what am I?”
Now, a new study has found some answers – and life emerged surprisingly early.
Life’s evolutionary timescale is typically calibrated to the oldest fossil occurrences. However, the veracity of fossil discoveries from the early Archaean period has been contested11,12. Relaxed Bayesian node-calibrated molecular clock approaches provide a means of integrating the sparse fossil and geochemical record of early life with the information provided by molecular data; however, constraining LUCA’s age is challenging due to limited prokaryote fossil calibrations and the uncertainty in their placement on the phylogeny. Molecular clock estimates of LUCA13,14,15 have relied on conserved universal single-copy marker genes within phylogenies for which LUCA represented the root. Dating the root of a tree is difficult because errors propagate from the tips to the root of the dated phylogeny and information is not available to estimate the rate of evolution for the branch incident on the root node. Therefore, we analysed genes that duplicated before LUCA with two (or more) copies in LUCA’s genome16. The root in these gene trees represents this duplication preceding LUCA, whereas LUCA is represented by two descendant nodes. Use of these universal paralogues also has the advantage that the same calibrations can be applied at least twice. After duplication, the same species divergences are represented on both sides of the gene tree17,18 and thus can be assumed to have the same age. This considerably reduces the uncertainty when genetic distance (branch length) is resolved into absolute time and rate. When a shared node is assigned a fossil calibration, such cross-bracing also serves to double the number of calibrations on the phylogeny, improving divergence time estimates. We calibrated our molecular clock analyses using 13 calibrations (see ‘Fossil calibrations’ in Supplementary Information). The calibration on the root of the tree of life is of particular importance. Some previous studies have placed a younger maximum constraint on the age of LUCA based on the assumption that life could not have survived Late Heavy Bombardment (LHB) (~3.7–3.9 billion years ago (Ga))19. However, the LHB hypothesis is extrapolated and scaled from the Moon’s impact record, the interpretation of which has been questioned in terms of the intensity, duration and even the veracity of an LHB episode20,21,22,23. Thus, the LHB hypothesis should not be considered a credible maximum constraint on the age of LUCA. We used soft-uniform bounds, with the maximum-age bound based on the time of the Moon-forming impact (4,510 million years ago (Ma) ± 10 Myr), which would have effectively sterilized Earth’s precursors, Tellus and Theia13. Our minimum bound on the age of LUCA is based on low δ98 Mo isotope values indicative of Mn oxidation compatible with oxygenic photosynthesis and, therefore, total-group Oxyphotobacteria in the Mozaan Group, Pongola Supergroup, South Africa24,25, dated minimally to 2,954 Ma ± 9 Myr (ref. 26).
Our estimates for the age of LUCA are inferred with a concatenated and a partitioned dataset, both consisting of five pre-LUCA paralogues: catalytic and non-catalytic subunits from ATP synthases, elongation factor Tu and G, signal recognition protein and signal recognition particle receptor, tyrosyl-tRNA and tryptophanyl-tRNA synthetases, and leucyl-and valyl-tRNA synthetases27. Marginal densities (commonly referred to as effective priors) fall within calibration densities (that is, user-specified priors) when topologically adjacent calibrations do not overlap temporally, but may differ when they overlap, to ensure the relative age relationships between ancestor-descendant nodes. We consider the marginal densities a reasonable interpretation of the calibration evidence given the phylogeny; we are not attempting to test the hypothesis that the fossil record is an accurate temporal archive of evolutionary history because it is not28.
Ishida, T. Sci Rep 14, 2086 (2024). https://doi.org/10.1038/s41598-024-52475-9
You can think of our atmosphere as a big chemistry set, a global churn of gaseous molecules and particles that constantly bounce off and change each other in complicated ways. While the particles are very small, often less than 1% of the thickness of human hair, they have outsized impacts. For example, particles are the seeds of cloud droplets, and the abundance of the particles changes the reflectivity and the amount of clouds, rainfall and climate.
There are biological underpinnings to aging—and so researchers are investigating cell manipulations, transfusions of young blood, and chemical compounds that can mimic low-calorie diets.
Scientists have taken a significant step towards the development of tailor-made chiral nanocarriers with controllable release properties. These nanocarriers, inspired by nature’s helical molecules like DNA and proteins, hold immense potential for targeted drug delivery and other biomedical applications.
The study, led by Professors Emilio Quiñoá and Félix Freire at the Center for Research in Biological Chemistry and Molecular Materials (CiQUS), highlights the intricate relationship between the structure of helical polymers and their self-assembly into nanospheres. By carefully designing the secondary chain, the researchers were able to modulate the acidity of the polymers, influencing their aggregation patterns and leading to the formation of nanoespheres with varying densities.
Intriguingly, the size of these nanospheres could be precisely controlled by simply adjusting the water-to-solvent ratio during their preparation, eliminating the need for stabilizers. This eco-friendly approach paves the way for sustainable synthesis of these particles.
In the decade since their discovery at Drexel University, the family of two-dimensional materials called MXenes has shown a great deal of promise for applications ranging from water desalination and energy storage to electromagnetic shielding and telecommunications, among others. While researchers have long speculated about the genesis of their versatility, a recent study led by Drexel and the University of California, Los Angeles, has provided the first clear look at the surface chemical structure foundational to MXenes’ capabilities.
Using advanced imaging techniques, known as scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS), the team, which also includes researchers from California State University Northridge, and Lawrence Berkeley National Laboratory, mapped the electrochemical surface topography of the titanium carbide MXene — the most-studied and widely used member of the family.
Their findings, published in the 5th anniversary issue of the Cell Press journal Matter (“Atomic-scale investigations of Ti 3 C 2 Tx MXene surfaces”), will help to explain the range of properties exhibited by members of the MXene family and allow researchers to tailor new materials for specific applications.
A research team led by Osaka University discovered that the new organic molecule thienyl diketone shows high-efficiency phosphorescence. It achieved phosphorescence that is more than ten times faster than traditional materials, allowing the team to elucidate this mechanism.
The paper is published in the journal Chemical Science.
Phosphorescence is a valuable optical function used in applications such as organic EL displays (OLEDs) and cancer diagnostics. Until now, achieving high-efficiency phosphorescence without using rare metals such as iridium and platinum has been a significant challenge. Phosphorescence, which occurs when a molecule transitions from a high-energy state to a low-energy state, often competes with non-radiative processes where the molecule loses energy as heat.
Awarded the 2023 Nobel Prize in Chemistry, quantum dots have a wide variety of applications ranging from displays and LED lights to chemical reaction catalysis and bioimaging. These semiconductor nanocrystals are so small – on the order of nanometers – that their properties, such as color, are size dependent, and they start to exhibit quantum properties. This technology has been really well developed, but only in the visible spectrum, leaving untapped opportunities for technologies in both the ultraviolet and infrared regions of the electromagnetic spectrum.
In new research published in Nature Synthesis (“Interdiffusion-enhanced cation exchange for HgSe and HgCdSe nanocrystals with infrared bandgaps”), University of Illinois at Urbana-Champaign bioengineering professor Andrew Smith and postdoctoral researcher Wonseok Lee have developed mercury selenide (HgSe) and mercury cadmium selenide (HgCdSe) nanocrystals that absorb and emit in the infrared, made from already well-developed, visible spectrum cadmium selenide (CdSe) precursors. The new nanocrystal products retained the desired properties of the parent CdSe nanocrystals, including size, shape and uniformity.
“This is the first example of infrared quantum dots that are at the same level of quality as the ones that are in the visible spectrum,” Smith says.
