Deng Hongkui's team of Peking University uses chemical reprogramming to completely reverse the "developmental clock" of human cells. | Global scientific news

Cell biology?

Chemical reprogramming reverses the "developmental clock" of human cells

Cell reprogramming can transform one cell into another type of cell, such as using oocyte cytoplasm or transcription factors, to reprogram somatic cells into pluripotent stem cells. In addition, exposure to an environment containing some small molecules (chemical stimulation) can also change the fate of cells, but it is more difficult to achieve in human cells. In a new study published in Nature, a team led by Deng Hongkui, a professor at Peking University, induced human cells into an intermediate state of plasticity, realizing the chemical reprogramming of human body cells.

?

The researchers screened and combined a large number of chemical small molecules and found that highly differentiated human adult cells can appear dedifferentiation similar to the dedifferentiation in the process of salamander limb regeneration under the action of specific chemical small molecular combinations. to reach a certain plastic intermediate state. Then, through further induction, they obtained CiPS cells that are highly similar to human embryonic stem cells (chemically reprogrammed pluripotent stem cells). Researchers have found that JNK signaling pathway is a major obstacle in the process of cell transformation into plasticity, and inhibition of this signaling pathway is essential to inhibit inflammatory signals to induce cell plasticity and regeneration. The key components of this signal pathway may become a new target for the study of human regeneration.

? Paleontology?

New discoveries may push forward the origin of life by 300 million years

Recently, a study published in the journal Progress of Science shows that life appeared on Earth at least 3.75 billion years ago, nearly 300 million years before the earliest signs of life are widely believed. In fact, the research team reached a similar conclusion in 2017. In a study published at the time in Nature, the researchers analyzed a rock sample from Quebec, Canada, which was about 37.5 to 4.28 billion years old, and found some fine filamentous traces of hematite mineralization. At the time, researchers thought it might be a trace left by early microbes, but the study also caused widespread controversy.

In the latest study, the team further analyzed the rock sample and found a dendritic structure nearly one centimeter long, surrounded by spherical or ellipsoidal structures. The researchers believe that such dendritic structures are difficult to produce through inanimate processes, and their mineral composition is similar to the metabolic by-products of modern iron-oxidizing bacteria, so they are likely to be microfossils.

? Scientific events?

Hundred people signed AI model review paper accused of plagiarism, Zhiyuan Research Institute responded

Recently, Google brain researcher Nicholas Carlini pointed out in a blog post that the Beijing Zhiyuan Research Institute had 10 large paragraphs suspected of plagiarism in the "A Roadmap for Big Model" (road map of the large model) published by the preprinted website arXiv, including an article by Kahlini's team and more than a dozen other authors.

Yesterday, Zhiyuan Research Institute issued a letter of apology on the issue of the A Roadmap for Big Model summary report, which admitted that there was a problem of plagiarism in the summary report and decided to "immediately delete the corresponding content from the report" and release a new version after strict review. " Zhiyuan Institute said that it has started to invite third-party experts to conduct independent review and relevant accountability, and will use this as a warning to further strengthen the construction of scientific research integrity and study style, improve system management, and prevent the recurrence of similar incidents.

? Physics?

Successful beam output of atmospheric neutron radiation spectrometer for spallation neutron sources in China

15:20 on April 2, the atmospheric neutron radiation spectrometer of Chinese Spallation Neutron Source (CSNS) successfully produced the beam. The subsequent beam performance tests show that the important parameters such as neutron beam size and distribution, neutron energy spectrum and flux are consistent with the expectation. The success of the spectrometer marks the successful development and installation of the spectrometer equipment.

The atmospheric neutron radiation spectrometer is the only domestic atmospheric neutron ground simulation accelerated testing platform jointly built by the Spallation Neutron Source Science Center and the Electronic Institute of the Ministry of Industry and Information Technology. It will provide atmospheric neutron accelerated irradiation test environment for new semiconductor devices, large-scale integrated circuits, key electronic equipment, new functional materials, biological irradiation effects, nuclear data and measurements, etc., to fill the gap in this field in China. It provides an advanced and powerful platform for atmospheric neutron testing and scientific research for China's high-tech development and industry standard formulation in the fields of aviation, aerospace, communications, energy, power electronics, modern transportation, medical and health, and high-performance computing. (Institute of High Energy Physics, Chinese Academy of Sciences)

? New technology?

The new generation of perovskite solar energy, the efficiency can reach 24%?

Efficient solar cells need to convert as much light energy as possible into electricity, which needs to be achieved through series cells. At present, high-performance series batteries generally contain organic semiconductors and perovskite, in which organic semiconductors can absorb ultraviolet and part of visible light, and perovskite can effectively absorb near-infrared light. ? However, there will be a certain loss when the energy is transferred between the two materials, which will reduce the efficiency of the battery to convert light energy into electric energy.

?

Recently, in a new study published in Nature, scientists placed a thin layer of indium oxide with a thickness of only 1.5 nm between organic semiconductors and perovskite-based batteries, which can effectively reduce energy loss at the interface. The photoelectric conversion efficiency reaches 24%, refreshing the photoelectric conversion efficiency of organic semiconductor-perovskite-based batteries. Studies have shown that such solar cells are highly sustainable and their performance may be further improved.

? Spaceflight?

ESA suspends cooperation with Russian moon project

Officials from the European Space Agency (ESA) announced on April 13 local time that they would stop cooperating with the Russian Moon series of robot missions on the moon. The resolution takes effect immediately, and the European Space Agency has asked for the Pilot D landing camera to be removed from the Lunar 25 mission, which was scheduled to be launched later this year.

The European Space Agency has also cooperated with Russia's follow-up missions to the moon, Lunar 26 and Lunar 27, which have now been halted. The Lunar 27 lunar rover, originally scheduled for launch in 2025, is planned to be equipped with an European-made optical navigation system based on artificial intelligence image analysis, as well as an underground drilling rig designed to take samples from lunar soil. European Space Agency officials say they are looking for alternatives to sending these technologies to the moon.

? COVID-19 epidemic situation?

As of 10:00, April 14, Beijing time, according to the latest statistics of Johns Hopkins University, there were 501,512,915 confirmed cases and 6,188,577 deaths of COVID-19 worldwide.

From 0 to 24:00 on April 13, 31 provinces (autonomous regions, municipalities directly under the Central Government) and Xinjiang production and Construction Corps reported 3020 new confirmed cases, according to the official website of the Nati