The pistil is the female reproductive organ of flowering plants. The stigma at the top is responsible for capturing and identifying pollen, and the style below provides a growth channel for the pollen tube. The presence of a clear, stable boundary between the stigma and style is essential to ensure sexual reproduction in the plant.
Stars mostly form in clusters. Open star clusters on the Milky Way disk are affected by the tidal force of the Milky Way during their long-term evolution, gradually disintegrating and releasing their member stars into the Milky Way disk. Neutron stars, as the remnants of the evolution of massive stars, also originate from star clusters. Currently, thousands of neutron stars acting as pulsars have been discovered in the Milky Way disk. However, astronomers have never directly observed neutron stars entering the Milky Way disk from birth clusters before. As a result, there has been a lack of observational evidence for the evolutionary origin of the neutron star population on the Milky Way disk.
Recently, the Hefei Institute of Physical Sciences, Chinese Academy of Sciences, has made progress in research on multifunctional electromagnetic wave absorbing superstructures. The team proposed a machine learning-assisted "material-structure-function" collaborative design strategy, using fused deposition modeling 3D printing technology to integrate the polyamide 6/carbon fiber composite (PACF) absorbing unit, low-loss pure polyamide 6 (N-PA) spacer layer and laser-induced PACF (LI-PACF) functional backplane to build a superstructure with multi-level resonant gradient impedance, achieving broadband and wide-angle microwave absorption from 2 to 40 GHz, with both structural load-bearing and electrothermal de-icing capabilities.
Natural products are an important source of modern therapeutic drugs. Their unique skeleton structure, abundant functional groups and multiple chiral centers form the chemical basis for a wide range of biological activities. In the later biosynthesis of such active natural products, iron(II)/2-oxoglutarate-dependent (Fe/2OG) enzymes can precisely introduce pharmacophore groups through a variety of reactions. Among them, the carbon-carbon bonding reaction catalyzed by this enzyme family can build a molecular skeleton with complex structure and significant biological activity. However, the related reaction process is complicated, and its mechanism of action is still unclear so far. In-depth analysis of the catalytic mechanism of this type of enzyme is of great significance for natural product biosynthesis research, new drug development and rational transformation of biocatalysts.
Asteroid impact is a natural disaster with low probability but complex disaster chain. The impact is accompanied by extreme dynamic effects such as ultra-high temperature, ultra-high pressure, ultra-high speed, etc., which will produce a large amount of sputtering dust. Sputtered dust is ejected into the atmosphere at high speed, and some dust enters the stratosphere and spreads, which may cause global environmental effects. Conducting research on the entire process from impact cratering to sputtering dust is of great significance to the study of near-Earth asteroid defense and Earth evolution. At present, due to technical and cost constraints, it is difficult to simulate real working conditions in indoor ultra-high-speed impact tests, and numerical simulation has become the main research method. However, most existing research focuses on a single process and lacks a systematic analysis method covering the complete chain of sputter dust formation - dust tropospheric movement - dust stratospheric diffusion.
In the past two decades, research on black hole thermodynamics has revealed the similarity between black holes and fluid systems—the existence of a small black hole-large black hole first-order phase transition in charged Anti-de Sitter (AdS) black holes. However, a key question remains unresolved - what thermodynamic behavior does a black hole exhibit in the "supercritical" region above the critical point? For a long time, people have known little about this, and the existing supercritical phase transition lines are not universal.
Standard DNA barcodes are widely used in fields such as biodiversity protection and traceability due to their advantages of strong universal primer adaptability and low sequencing costs. For closely related species, complex taxa with frequent hybridization and recent radiation evolution, standard DNA barcodes cannot meet the needs of accurate identification due to limited sequence variation and insufficient resolution. Although the strategy of shallow genome sequencing to obtain the complete plastid genome (super barcoding) has improved the identification rate of some difficult taxa, the uniparental inheritance characteristics of the plastid genome make it limited in the analysis of introgressed taxa.
Boron plays an important role in glass and ceramic manufacturing, agricultural production and other fields. Although the salt lakes in Qinghai and Tibet are rich in liquid boron ore, the high-salt environment and the reactive inertness of boric acid molecules make efficient and selective extraction of boron challenging.
Marine heat waves are extreme high temperature events in which sea surface temperatures are abnormally warm and last for days to months. Global warming is making such events more frequent and more intense, with impacts throughout the marine food web, from phytoplankton to top predators. As the basis of the marine food web, phytoplankton supports most of the ocean's primary productivity through photosynthesis, and its changes will affect fishery resources and ocean carbon sinks through cascade effects. The western and central equatorial Pacific has previously been considered to be slightly affected by marine heat waves. The average annual heat wave days in this area are only 22, and the average intensity is only 1.2°C, which is far lower than most sea areas in the world, so it is regarded as a "safe haven" for marine heat waves.
Life Sciences#Chinese Academy of Sciences#科研进展#CAS#genomics#biology
Modern main banana varieties are highly dependent on vegetative reproduction and have problems such as narrow genetic base and low genetic diversity. There are about 80 species in the Musa family. Different groups show diversity in chromosome base numbers (such as n =11, 10 and 9) and bud color and other traits. They are an ideal group for studying the evolution of plant chromosome structures and the differentiation of floral organ traits. However, there has been a long lack of direct evidence at the genomic and cytogenetic level regarding the evolutionary formation mechanism of these different chromosome base numbers and the intrinsic correlation between chromosome structural variation and flower bud color differentiation.
Life Sciences#Chinese Academy of Sciences#科研进展#CAS#genomics#biology
