In the 1940s and 50s, the coast of Los Angeles, USA, was a hotspot for the production of the pesticide DDT and a site for dumping pollutants. Although this chemical has been completely banned, its impact can still be felt decades later. A recent study has found that there are large amounts of DDT-related chemicals present in the deep sea of this area.
Researchers used remotely operated submersibles to collect sediment and fish samples from the ocean floor for testing. Their findings were astonishing—up to 15 different related compounds were detected in the sediment, and 10 different DDT-related compounds were found in the 215 fish collected. These lethal chemical components demonstrate that the ocean floor sediments may serve as a source of DDT pollution in the deep-sea ecosystem.
The research team specifically studied some indigenous deep-sea fish, which do not feed on ocean floor sediments, yet still contained DDT compounds in their bodies. This triggered scientists’ curiosity about the possible mechanisms of pollution propagation. The researchers emphasized the importance of understanding the distribution, diffusion, and pathways of DDT compounds in the ocean, and suggested a need for more extensive analytical studies.
In another field of study, people have specific preferences for the temperature of different types of alcoholic beverages. For example, people usually choose chilled beer and white wine, while preferring warm red wine and yellow rice wine. The latest research indicates that the temperature of a beverage can affect people’s perception of the taste of alcohol.
Scientists observed through experiments that as the concentration of alcohol increases, the contact angle of the solution changes, reflecting the interaction between molecules inside the droplet. At lower ethanol concentrations, ethanol molecules form a denser tetrahedral structure around water molecules; as the concentration increases, ethanol molecules connect in a chain-like structure.
Interestingly, changes in the temperature of ethanol solutions affect the stability of these structures, suggesting that the perceived taste differences of alcohol may be related to changes in the physical properties of the solution at different temperatures. In other words, both cooling and heating treatments can affect people’s taste experience of alcohol, which explains the special preference for chilled beer.
The research reveals that at 5% and 11% ethanol concentration, which corresponds to the ethanol content of beer, when the temperature drops to 5 degrees Celsius, the chain-like structure of the liquid significantly strengthens while the tetrahedral structure decreases considerably. This change could enhance the unique flavor of alcohol, making people prefer chilled beer even more.
In the field of quantum computing, a research team led by Academician Jian-Wei Pan of the University of Science and Technology of China used a “bottom-up” quantum simulation approach to successfully achieve the fractional quantum anomalous Hall state of photons. This achievement has not only attracted wide attention in the academic community, but because it eliminates the dependency on extremely strong external magnetic fields and paves the way for comprehensive measurements and controllable applications of microscopic properties in highly integrated quantum systems, it also provides an important platform for in-depth studies of future quantum states.
A new discovery in astronomy involves the strange co-dancer between the Moon and Earth—”oscillating celestial bodies.” These are quasi-satellites with stable orbits that appear to revolve around Earth while orbiting the Sun. Tsinghua University’s research team published their findings in the journal Nature Astronomy, which suggests that these near-Earth asteroids may be dynamically related to specific impact craters on the moon’s surface. By simulating and analyzing the impact craters, the team identified that the lunar impact craters needed to produce “oscillating celestial body” sized fragments should be at least tens of kilometers in diameter, concentrating around the “youngest” large impact crater—Bruno crater. This study not only provides clues to the origins of these near-Earth asteroids but also introduces a possible monolithic asteroid group structure. These findings provide direction and expected targets for future exploration missions such as Tianwen-2.
Scientists have long believed that there is some connection between the brain and the immune system, but know very little about its specific function. Now, a new study published in Nature has unveiled this mystery, confirming that cells within the brainstem can sense immune signals from the peripheral parts of the human body, and that these cells are key regulators of the body’s inflammatory response.
Historical research has indicated that the vagus nerve influences immune responses, but exactly which brain neurons are activated by immune stimuli has been difficult to determine. In this study, the research team experimented on mice by injecting an inflammation-inducing bacterial solution into their abdomen and monitoring the response patterns of their brain cells.
The researchers observed that the brainstem neurons of the mice were able to respond to these immune challenges. The results showed that pharmacologically activating certain neurons could significantly reduce the levels of inflammatory molecules in the mouse blood. Conversely, when these neurons were inhibited, problems with uncontrolled immune responses occurred.
Further research discovered that there are two different groups of neurons within the vagus nerve; one group responds to pro-inflammatory immune molecules, and the other responds to anti-inflammatory molecules. This suggests that the brain maintains a delicate balance between the signals of molecules that promote and inhibit inflammation.
This groundbreaking study provides a new perspective on understanding how the brain can affect overall health by regulating inflammation. It may also provide a basis for the development of new strategies to treat autoimmune diseases and other ailments caused by excessive immune responses.
