In the 1940s and 1950s, the coast of Los Angeles, USA, was a hotspot for the production of DDT insecticide and a dumping ground for pollutants. Although this chemical has been banned, its effects can still be felt decades later. A recent study has found that a large quantity of DDT-related chemicals exists in the deep sea of this region.
Researchers used remote-controlled submersibles to collect sediment and fish samples from the seafloor for testing. Their findings were astonishing—up to 15 different related compounds were detected in the sediments, and 10 different DDT-related compounds were found in the 215 fish collected. These toxic chemical components proved that sea bed sediments could be a source of DDT pollution in the deep-sea ecosystem.
The research team specifically studied some indigenous deep-sea fish species, which do not feed on the seabed sediments. Yet, their bodies still contained DDT compounds, which aroused scientists’ curiosity about possible pollution transmission mechanisms. The researchers emphasized the importance of understanding the distribution, diffusion, and transmission routes of DDT compounds in the ocean and suggested more extensive analytical research.
In another area of research, people have a particular preference for the temperature at which different types of alcohol are consumed. For example, people usually choose to drink beer and white wine cold, while red wine and yellow rice wine are consumed warm. The latest research indicates that the temperature of a drink can affect people’s perception of the taste of alcohol.
Scientists observed through experiments that the contact angle of a solution changes differently with the increase in alcohol concentration, reflecting the interactions between molecules inside the droplet. At lower ethanol concentrations, ethanol molecules form a more dense tetrahedral structure around water molecules; at higher concentrations, ethanol molecules connect to each other in a chain-like structure.
Interestingly, when the temperature of the ethanol solution changes, the stability of these structures is affected, indicating that the perception of the alcohol taste may be related to the change in physical properties of the solution at different temperatures. In other words, both chilling and heating treatments can affect the taste experience of alcohol, which may explain the special fondness for chilled beer.
The research revealed that in 5% and 11% ethanol solutions, which correspond to the alcohol concentration of beer, when the temperature is lowered to 5 degrees Celsius, the chain-like structure of the liquid becomes significantly stronger while the tetrahedral structure substantially reduces. This change may enhance the unique flavor of alcohol, making chilled beer more preferred.
In the field of quantum computing, a research team led by Academician Pan Jianwei of the University of Science and Technology of China has successfully achieved the fractional quantum Hall state of photons by using a “bottom-up” quantum simulation method. This achievement not only garnered widespread attention in the academic community because it liberates the reliance on extremely strong external magnetic fields and paves the way for comprehensive measurements and controllable applications of the microscopic properties of highly integrated quantum systems, but also provides an essential platform for in-depth research into future quantum states.
A new discovery in the field of astronomy involves the intriguing co-dancer between the Moon and Earth—the “oscillating satellite.” This is an orbitally stable quasi-satellite that appears to revolve around the Earth while orbiting the sun. A research team from Tsinghua University published their findings in the journal Nature Astronomy, indicating that these near-Earth asteroids may be dynamically associated with specific impact craters on the Moon’s surface. By simulating and analyzing impact craters, the team determined that the Moon’s impact craters need to be at least several tens of kilometers in diameter to produce debris the size of an “oscillating satellite,” focusing on the “youngest” of the large craters—the Bruhnes Crater. This study not only provides clues to the origin of these near-Earth asteroids but also introduces a possible group of monolithic structural asteroids. These findings provide research direction and expected targets for future exploration missions, such as Tianwen No. 2.
Scientists have long believed that there is some connection between the brain and the immune system but knew very little about its specific function. Now, a recent study published in Nature has unveiled this mystery, confirming that cells within the brainstem can detect immune signals from the periphery of the body, and that these cells are key regulators of the body’s inflammatory response.
Historical studies have indicated that the vagus nerve affects the immune response, but it has been difficult to pinpoint which neurons in the brain are activated under immune stimulation. In this study, the research team experimented on mice, injecting them with a bacteria solution that causes inflammation in their abdomens, and monitored the response patterns of their brain cells.
Researchers observed that the mice’s brainstem neurons were able to respond to these immune challenges. Experimental results show that pharmacologically activating specific neurons significantly reduced the levels of inflammatory molecules in the mice’s blood. Conversely, when these neurons were inhibited, problems with uncontrolled immune responses arose.
Further research revealed that there are two different groups of neurons within the vagus nerve, one responsive to pro-inflammatory immune molecules, and the other to anti-inflammatory molecules. This suggests that the brain maintains a delicate balance between molecular signals that promote and suppress inflammation.
This groundbreaking study provides a new perspective on understanding how the brain influences bodily health by regulating inflammation. It may also provide a basis for developing new strategies to treat autoimmune diseases and other illnesses caused by excessive immune responses.
