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Medical science

Successful transplantation of porcine kidney into brain-dead human for the first time

Physics

Tongji University realizes space charging at a distance of 2 meters.

In wireless energy transmission technology, non-radiant wireless energy transmission (that is, electromagnetic induction charging) can transmit energy efficiently, but the effective transmission distance is limited to several times the size of the transceiver; although radiated wireless energy transmission (such as radio, laser) can transmit energy over a long distance, it requires complex control mechanisms to track moving energy receivers.

Chemistry

A new technology that can crack the crystal structure of all materials

Analyzing the crystal structure of materials, that is, the orderly arrangement of internal atoms, is very important to understand their physical and chemical properties. Current techniques, such as X-ray diffraction, often only better measure perfect crystals. But in fact, most materials are polycrystalline, they contain multiple grains, so they will produce a variety of signals mixed together, and it is difficult to measure the crystal structure of the material. However, a recent study in Nature has developed a small atom serial femtosecond laser crystal (small-molecule serial femtosecond crystallography,smSFX) technology to solve this problem.

Compared with the old technology to measure millions of grains at one time, smSFX uses high-energy X-rays to illuminate a single grain continuously and quickly and produce diffraction, so it can measure small crystal structure with higher precision. The scientists measured the powdered hybrid chalcogenide (hybrid chalcogenolate) by smSFX, and calculated the lattice structure according to the diffraction signal, and found that it was not consistent with the theoretical prediction. Theoretically, smSFX can be used to measure all materials that are difficult to grow perfect crystals, so it has great potential for application.

Physics

Computer simulation of "minimum cell"

As the basic unit of life, cells contain a variety of organelles and molecules, and carry out a variety of chemical reactions, and its complexity brings difficulties to computer simulation. To this end, a study on "cells" aims at the simplest living cell, Mycoplasma, and removes most of the genes in the cell, leaving only a simplified version of the genome that supports basic life functions such as DNA replication, growth and division, and simulates the three-dimensional structure and function of this "smallest cell" on a computer for the first time.

Scientists first constructed a three-dimensional model of the smallest cell on an atomic scale, including the exact location and structure of thousands of cellular components, and then simulated the intracellular changes in its complete life cycle. including molecular diffusion, chemical reactions and energy required. At the same time, the model can also predict the response of cells when the genome, external environment and other internal and external conditions change. In the study, scientists used this model to calculate the life cycle of messenger RNA and the relationship between cell membrane structure and cell volume. This model will help us to understand cell biology more deeply.

Medical science

Astronauts stay in space for a long time or are more prone to anemia.

Astronauts suffer from space anaemia (space anemia) when they go into space, and previous studies have suggested that the situation will improve as they adapt to life in space. But on Earth, 2 million new and damaged red blood cells are produced and damaged every second, while living in space can lead to a 50% increase in the number of damaged red blood cells, which may lead to anemia, according to a new study published in Nature Medicine.

The researchers collected blood samples from 14 astronauts before leaving Earth, during their six-month stay on the International Space Station and after returning to Earth, and analyzed their general condition. They found that compared with living on Earth, the number of cell damage caused by astronauts on the International Space Station increased to nearly 3 million, with an increase of 54 per cent. When five of the astronauts return to Earth, the amount of hemoglobin in their blood is too low to provide enough oxygen to some tissues of the body. The study also found that three to four months after returning to Earth, the effect persisted-the amount of red blood cell damage in astronauts increased by 30% compared to before going into space. Anemia can lead to fatigue, weakness and dizziness, which can be dangerous to astronauts, and improving the astronauts' diet and other conditions may relieve this symptom.

Astronomy

Analysis of the current on the event horizon of a black hole

If a black hole is charged or rotates, its interior produces a surface similar to the event horizon (that is, the outer edge of the black hole), which is called the inner horizon of the black hole. Due to the quantum effect, an electric current may be generated on the event horizon of the black hole. In previous studies, scientists thought that this current was mainly generated by particles with opposite charges generated spontaneously inside the black hole, which would cause discharge in the black hole region within the inner event horizon. A recent study published in the physical Review KuaiBao tested this view in theory.

The researchers analyzed the vacuum polarization caused by the charged scalar field near the event horizon of the charged black hole and derived the formula of the current on the inner event horizon. They found that the inner horizon current can be contributed by positively charged particles or negative particles, depending on the parameters of space-time and quantum field; black holes whose parameters are close to the maximum value tend to reduce the inner event horizon, which ensures that the charge it carries does not exceed the maximum allowable value; in some cases, the charge in the region within the inner event horizon can be increased by quantum effects. The results exceeded the researchers' expectations, saying that the next step would be to analyze the rotating black hole in a similar way to test whether the quantum effect increases the angular momentum near the event horizon of the black hole.