Biden says it will weaken Russia's space program, and Russia responds to freezing cooperation space stations in the United States and Europe.

Cooperation between the United States and Russia is crucial to the construction and operation of the International Space Station. After the Columbia space shuttle disintegrated on its return to Earth in 2003, Russia stepped in to launch astronauts for the United States to the International Space Station. After the decommissioning of the space shuttle in 2011, the United States relied on Russian spacecraft to transport astronauts to and from the International Space Station. It was not until 2020 that the SpaceX manned dragon spacecraft allowed American astronauts to re-enter orbit from the United States mainland. In response to the space cooperation between the United States and Russia, NASA also responded that the new export restrictions will not affect its cooperation with Russia on the operation of the International Space Station. (thepaper.cn, Russian satellite news agency)

Chemistry

Electrolytic water is often used for electrochemical production of oxygen, but the electrocatalytic oxygen evolution reaction (OER) is relatively slow, which not only consumes a lot of electric energy, but also restricts the overall efficiency of electrolytic water. At present, iridium, ruthenium and other precious metal-based catalysts are mainly used in large-scale production, but these transition metals are rare and expensive. Therefore, there is an urgent need to develop cheap and efficient oxygen production catalysts. Recently, a new study published in Natural Materials has developed a cheap oxygen-producing catalyst called Metal hydroxide-Organic Framework (MHOF).

Spaceflight

11:06 on February 27th, the long March 8 Yao-2 carrier rocket detonated and took off from the Wenchang Space launch site in Hainan. Subsequently, the lifted 22 satellites were successfully put into orbit, and the launch mission was a complete success. It has set a record for the launch of more than one satellite in China. This flight test carried 22 commercial satellites, including Hainan 01 and 02, Universiade (Star Age-17), Wenchang 01 and 02, Taijing 3 01, etc., which were respectively from 7 development units. mainly used for earth observation, low-orbit Internet of things communication, space science experiment It can provide services such as resource investigation, synthetic aperture radar data support, data collection of distributed terminals of the Internet of things, in-orbit scientific experiments and technical verification, and ship information collection and processing in Hainan and surrounding provinces.

With a launch capacity of 3.5 to 5 tons in the sun synchronous orbit, the long March 8 carrier rocket is particularly suitable for the current satellite market demand, and will gradually become the main force of China's medium and low orbit rockets. Low-orbit optical remote sensing satellites, navigation satellites, Internet broadband satellites, etc. to achieve global coverage, at least a dozen, as many as hundreds, so there is a great demand for the launch of the long March 8 rocket in the future. At present, the construction of Hainan final assembly test plant has begun, and the launch station is also in the process of demonstration. At that time, a Chang 8 rocket can be launched in seven days and 50 rounds a year. (CCTV News client, Guangming Daily)

Physics

Physicists re-simulate axion mass to find dark matter

85% of the matter in the universe is made up of dark matter, which affects the motion and evolution of celestial bodies, but the composition of dark matter is not yet clear. The axion was proposed as an elementary particle in 1978, and scientists believe that intense cosmic activity can be thrown out of the axion to produce dark matter. However, the axion search and mass calculation are very complex, and the coverage of experimental devices such as microwave resonators is too small, which brings difficulties for related research. Recently, a simulation study published in Nature Communications narrowed the mass range of axions.

Archaeology

Remains of ancient rock paintings discovered for the first time in Hainan

Recently, when the Institute of Vertebrate Paleontology and Palaeoanthropology of the Chinese Academy of Sciences conducted a prehistoric archaeological survey in Wangxiaxiang, Changjiang Li Autonomous County, Hainan Province, a remains of ancient rock painting was found at the top of the Paleolithic site Qiantie Cave. This is the first remains of rock paintings found in Hainan, and it is also the southernmost remains of rock paintings found in China.

The researchers collected, measured, located and graded the rock paintings. by comparing and analyzing the geology and geomorphology, color and shape of rock paintings, and so on, the researchers preliminarily judged that this rock painting group was a typical ancient Baiyue national rock painting pattern. most of them depict the squatting figure patterns of gathering, hunting and totem worship at that time, which are similar to the rock paintings found in Huashan, Zuojiang, Guangxi. Next, the researchers plan to make a comprehensive and in-depth study with experts in geology, environment and rock painting to further determine the age of the site. (CCTV News)

Medical science

Metformin is a first-line drug for the treatment of type 2 diabetes, which can reduce the weight of diabetics and the risk of cancer caused by diabetes, as well as the amount of fat in the liver. Previous studies have suggested that metformin can activate downstream AMPK proteins involved in metabolic homeostasis through lysosomal pathway to alleviate a series of symptoms in patients with diabetes, but the specific process is not clear.

Recently, in a study published in the journal Nature, scientists at Xiamen University revealed the detailed mechanism by which metformin works. They first screened 113 proteins that could bind to metformin and inhibited the expression of these proteins one by one through cell experiments. They found that when the expression of presenilin enhancer 2 (PEN2) was inhibited, the cells were not sensitive to metformin and did not activate AMPK protein, and further revealed the specific action process of metformin in cells: metformin binds to a subunit of lysosomal pump v-ATPase, inhibits the function of v-ATPase, but activates AMPK protein. Further studies have shown that knockout of the pen2 gene in the liver and intestine will lead to an increase in fat in the liver, while the hypoglycemic effect of the intestine is inhibited. This study may help to make better use of metformin and reduce side effects.