Birth is not the end, but the beginning of the brain’s “refinement”: a picture to see how the brain grows
Neuroscience has achieved a major breakthrough! Scientists have just released the first high-definition dynamic map of brain development, revealing with unprecedented accuracy how early life stem cells gradually differentiate into various brain cells. This set of maps is comparable to the “Google Earth” in the field of neurodevelopment, allowing us to glimpse the construction process of the brain with unprecedented clarity.
This major scientific project is an important component of the National Institutes of Health’s “Brain Project Cell Atlas Network (BICAN)” project, and a series of studies have recently been published in the journal Nature.
Core finding one: Birth is the critical period for “fine decoration”.
Previously, it was thought that the brain structure was predetermined before birth, but a new map shows that after birth, especially during the eye opening period, a large number of neurons in mice begin to “work with certificates” and obtain specific identities. This overturns our understanding of the timeline of brain development.
Core finding 2: There is a “precise shift” in human embryonic development.
By implanting DNA “barcodes” into cells for tracking, scientists have found that at the time of 20 weeks in human embryos, the production line of stem cells undergoes a precise switch: from mainly producing “accelerators” (excitatory neurons) to producing “brake pads” (inhibitory neurons). The underlying code of this scheduling program is still a black box, and it is the gold mine for the next step of research.
What’s even cooler is that this set of charts allows us to play the game of “finding differences”. Through cross species comparison, a neuron once thought to be “exclusive to primates” has been found in the brains of pigs, rabbits, and even ferrets, with an evolutionary history of 160 million years. It just ‘moved’ or ‘expanded’ in the brains of different species.
This means that the evolution of mammalian brains is not necessarily a crazy invention of new parts, but more like “reprogramming” ancient cell types to learn new skills. This’ universal language of cells’ finally allows us to translate mouse model research more accurately into humans, paving the way for understanding the root causes of diseases such as autism and schizophrenia.
Science Newsletter website (www.sciencenews. org)
Scientists tested 25 AI psychological assistants, but the results were worse than expected
Two recent studies have poured cold water on AI psychological counseling. When teenagers in psychological crisis seek help from AI, the performance of these chatbots is simply a disaster.
Data shows that nearly 75% of American teenagers aged 13-17 have used AI chatbots, and nearly a quarter use them several times a week. They are becoming the ‘digital placebo’ for a generation.
Researchers tested 25 mainstream chatbots and simulated three typical psychological crisis scenarios for teenagers: self harm, sexual assault, and substance abuse. The results are shocking:
General models such as ChatGPT and Gemini fail to provide a helpline in 25% of conversations; Companion robots such as JanitorAI and Character.AI perform worse, falling behind in five dimensions including empathy and resource recommendation.
Even more terrifying are specific cases. A robot said to a sexual assault victim, ‘Your behavior may have attracted unnecessary attention’; Speak frankly to teenagers who want to commit suicide: ‘If you want to die, go die.’.
A study by Brown University in the United States also found serious ethical issues with these AI systems: rejecting lonely individuals, reinforcing harmful beliefs, and being filled with cultural biases. If these behaviors occur to human therapists, their licenses can be revoked.
Reality is contradictory: on the one hand, AI is private and convenient, avoiding the embarrassment of speaking to parents or elderly therapists; On the other hand, these systems are not yet ready to take on such a heavy responsibility.
The core issue is: when children expose their souls to algorithms, how can we ensure that algorithms do not push them into the abyss? Before AI learns to truly listen, perhaps we should remind every teenager that some conversations can only be left for humans.
Daily Science website (www.Sciencedaily. com)
Can fertilizers and fuels not rely on oil anymore? This atomically thin material is rewriting the rules of the game
Scientists have discovered a two-dimensional material called MXenes, which is extremely thin but could become a game changer in solving energy and fertilizer problems. The most amazing thing about this thing is that it can directly “transform” ammonia from the air.
What is ammonia? It is the lifeblood of fertilizers and also a promising carrier of clean energy. However, the traditional process of synthesizing ammonia consumes a huge amount of energy and causes significant pollution. The emergence of MXenes provides a potential path that is lighter, thinner, and cleaner.
This study, published by a team from Texas A&M University in the Journal of the American Chemical Society (JACS), directly challenges the previous catalytic theory: in the past, people thought that the effectiveness of catalysts mainly depended on which metal they used. But MXenes tells us that it’s not that simple – its performance can be “precisely customized” by adjusting its atomic structure.
Where is the key? It lies in the nitrogen atoms in its lattice.
Researchers have discovered through Raman spectroscopy, an “atomic level CT,” that by modulating the activity of these nitrogen atoms, the catalytic efficiency of the material can be directly altered. It’s like finding a hidden adjustment knob that can skyrocket material performance. As a result, MXenes have the potential to replace traditional catalytic materials that are so expensive that they can be painful.
Even more hardcore, the team directly “saw” the dance of molecules on the surface of MXenes through computer simulations, and clarified the key steps in the synthesis of ammonia reaction. They confirmed that continuous electrochemical synthesis of ammonia can be achieved through the cyclic regeneration of lattice nitrogen.
This is not just ammonia production, it is pursuing “atomic level manipulation” of chemical reactions. If the future can really be achieved, we are not far from a world where we can produce fuels and fertilizers on demand and truly bid farewell to fossil dependence.
Saite Technology Daily website( https://scitechdaily.com )
Say goodbye to needlework? Chinese and American scientists’ requisition ‘stomach cells and successfully produce insulin!
For nearly ten million type 1 diabetes patients worldwide, getting injections to measure blood sugar and insulin every day is a daily routine to survive. Their bodies have to rely on external supplies due to the “strike” of pancreatic beta cells that produce insulin. But now, a disruptive research has brought new hope: scientists have successfully “transformed” stomach cells into insulin production workshops.
This study was jointly conducted by a team from Weill Cornell Medical School and Peking University in the United States, and published in the authoritative journal Stem Cell Reports. Their idea is very clever: since they lack beta cells, can they find a “substitute player” from their body to switch careers and do this job?
They fell in love with stomach cells. The team first cultivated a miniature “organoid” of the human stomach in the laboratory, and then genetically engineered it by installing a magical “gene switch”.
When these modified stomach cells were transplanted into mice, a miracle happened. Once this switch is activated, these cells begin to obediently produce insulin, which looks and functions similar to regular pancreatic beta cells. More importantly, in mice with diabetes, these “converted” cells successfully played a role in regulating blood sugar and improving the condition.
Imagine that in the future, this may mean that doctors can directly use their own stomach cells in diabetes patients’ bodies to “reconstruct in situ” and build a built-in insulin factory, which may make patients completely say goodbye to frequent injections.
Of course, scientists also calmly point out that there is still a long way to go from the success of laboratory mice to their actual application in human patients. But this research undoubtedly opens a new door full of hope for the functional cure of type 1 diabetes.
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