The newest global technological information.

The third cured HIV infected person may have appeared.

At the retrovirus and opportunistic infections conference held in Denver on Tuesday, a team of researchers announced that an HIV-infected person had been free of HIV for 14 months after receiving a new combination of stem cell therapy.

If the infected person does not detect HIV for a long time, she will become the third person to be cured of HIV infection in history.

It is reported that the infected person is a middle-aged, mixed-race woman from the United States who was diagnosed with HIV in 2013 and acute myeloid leukemia in 2017.

She then received a umbilical cord blood transplant, and the donor carried a rare mutation that prevented HIV from invading the cells.

In addition, she received hematopoietic stem cell transplants from relatives to provide short-term support for her immune system.

After the operation, the transplant effect of this woman was ideal and there was no graft-versus-host reaction.

The woman stopped taking antiretroviral drugs 14 months ago and so far there is no sign of a rebound in the HIV virus.

Prior to this, two patients who have been cured of HIV infection have received bone marrow transplantation, which is highly invasive and high-risk.

Although researchers do not know exactly why cord blood transplantation works well, this method is easier to implement and less painful for patients.

In addition, the gender and ethnic background of the infected person also provides new evidence for HIV clinical studies targeting a wider population.

Astronomy.

Confirm the "unified model" of active galactic nuclei.

Active galactic nuclei are high-energy regions at the centers of some galaxies and are thought to be driven by supermassive black holes.

The spectral characteristics of active galactic nuclei are related to the region of light emitted, and different spectra divide them into two types: type Ⅰ and type Ⅱ celestial bodies.

But there is a "unified model" that believes that they are all caused by the same mechanism, and this difference is sometimes caused by the observation line of sight obscured by dust rings that surround and pour into the central black hole.

Medical science.

General blood type organs for transplantation.

ABO blood group is determined by carbohydrate antigens on the surface of cells. Blood cells and vascular cells of individuals with type O blood do not contain An and B antigens on the surface, and there are anti-An and B antibodies in the body. Organ transplantation from other blood type donors will lead to severe immune rejection.

This makes patients with type O blood have a disadvantage in the allocation of organ transplantation. for example, the mortality rate caused by waiting for lung transplantation is 20% higher than that of other patients, and the average waiting time for kidney transplantation is about 2 years longer than patients with types An and AB.

A study published Feb. 16 in the journal Science Translational Medicine provides a solution.

In the laboratory, the researchers used the isolated lung perfusion repair system (EVLP) to pump a series of enzymes into the lungs of type A blood donors who were not eligible for transplantation to remove blood group antigens on the cell surface, while other lung samples were used as controls.

Since then, the researchers added type O blood rich in anti-An antibodies to the lung tissue of both groups. the results showed that there was no immune rejection in the enzyme-treated lung tissue, while immune rejection occurred in the control group.

The researchers say the study successfully created a universal type O blood transplant organ, providing a basis for alleviating the supply pressure and uneven distribution of organ transplants around the world.

They plan to conduct clinical trials in the next 12 to 18 months.

Physics.

Verification of general relativity with atomic clocks only 1 mm apart.

Atomic clocks are timed by electromagnetic waves emitted by atoms when they absorb or release energy.

According to general relativity, the stronger the gravitational field, the less energy the atom absorbs from the electromagnetic field, thus reducing the vibration frequency of the atom.

As a result, atomic clocks move more slowly at lower elevations, also known as the time expansion effect.

Previously, this effect was verified by comparing two atomic clocks 33 centimeters apart.

Recently, a study published in the journal Nature verified the effect of time expansion by comparing two atomic clocks that are only 1mm apart.

The researchers placed about 100000 ultra-cold strontium atoms in an optical lattice and made atomic energy jump between two energy levels by precisely controlling the energy state of the atoms, making atomic energy jump consistently for 37 seconds.

After measuring and comparing the vibrational frequencies of the energy level transitions of strontium atoms located at the top and bottom of the optical lattice, it is found that the frequency difference accords with the prediction of general relativity.

Using this method, they improve the accuracy of the atomic clock by 50 times, which is of great significance to the application of atomic clock calibration techniques such as GPS positioning.

Climatic change.

Important factors affecting global warming in the 21st century.

Society and politics determine climate-related policies to a large extent, including greenhouse gas emissions, but social and political impacts on climate change are hardly taken into account in existing climate models and projections.

Recently, a study published in Nature found important social and political factors affecting global warming in the 21st century, thus emphasizing the importance of considering the basic interaction between climate and society in climate change modeling.

Using a comprehensive multidisciplinary model, combined with a wide range of social, political and technical data, the researchers simulated 100000 possible future emission trajectories and policies.

These paths can be divided into five groups, and in different scenarios, the global temperature in 2100 is 1.8 degrees 3.6 degrees Celsius higher than the average between 1880 and 1919.

Researchers have identified a number of important factors that can influence the trajectory of emissions and climate change throughout the 21st century, including public perception of climate change, the cost and effectiveness of mitigation policies, and the responsiveness of political institutions.

Physics.

High precision R value measurement in positron annihilation by BESIII experiment.

R value is a physical quantity in the process of positron annihilation.

The difference between the experimental measurement and the theoretical calculation of the latest Miuzi abnormal magnetic moment is about 4.2 times of the standard deviation, suggesting the existence of new physics.

The theoretical calculation value needs R value as the input parameter.

Because of the inapplicability of perturbation quantum chromodynamics in the low energy region (< 5 GeV), experimental measurement is the only way to obtain high precision R values.

Therefore, the R value measures the abnormal magnetic moment of the Miuzi.