Volcanoes on the dark side of the moon

Scientists in Beijing have analysed rock samples from a lunar mission that suggest there were once volcanoes on the dark side of the moon.

The half of the moon not visible from Earth, referred to as the lunar farside, is very different in its geology from the nearside, and has been much less extensively explored. During a 53-day-long mission earlier this year, the Chang’e 6 lander used a robotic scoop and drill to take almost 2kg of samples from the basalt planes on the moon, which are known as maria.

The researchers used scanning electron microscopy, electron microprobe analysis and secondary-ion mass spectrometry to determine the mineral composition of the 108 fragments of mare basalt. They used a technique called Pb-Pb dating, which exploits the fact that some forms of lead undergo radioactive decay over time. Calculating the ratio between the amount of radiogenic vs non-radiogenic forms of lead in a sample can therefore give information about its age.

The composition of these samples suggests that mare volcanism occurred on the lunar farside more than 4.2 billion years ago, and persisted for more than 1.4 billion years. These findings help confirm that existing models of the history of the moon, which were previously only based on samples from nearside rock, also apply to the farside. Understanding more about the lunar dark side could help shed light not only on the history of the moon, but the origins of the solar system itself.

“Understanding more about the lunar dark side could help shed light not only on the history of the moon, but the origins of the solar system itself”

Fat cells have a memory

Scientists have found evidence that the fat cells of obese individuals undergo long-lasting changes to their DNA that could explain why many individuals find it so difficult to maintain weight loss.

A group of researchers from Zurich performed single-nucleus RNA sequencing (snRNA-seq) in adipocytes (fat cells) from humans and mice. They found that genes were expressed differently in the adipocytes from individuals who were or had previously been obese, compared to individuals who had never been obese. The group also found that experiencing obesity caused epigenetic changes in the mouse adipocytes, meaning there were additional chemical alterations to the DNA or the proteins around which it is stored, and that these epigenetic changes were not reversed when the mice lost weight.

The scientists believe that these epigenetic differences are responsible for the different way that proteins were made in the adipocytes from obese and formerly obese individuals, and offer a mechanism for the long-term persistence of an epigenetic “obesogenic memory”. Furthermore, these differences in mouse adipocytes seemed to result in the cells growing faster and absorbing nutrients more quickly than cells from mice that had never been obese, which resulted in the formerly obese mice gaining weight more quickly. This could explain why many individuals find it so difficult to maintain weight loss (often referred to as the ‘yo-yo’ effect), and offer a new target for weight management strategies in the future.

Photothermal chip detects diseases within 30 minutes

Engineers have developed a compact chip that can detect multiple diseases simultaneously using a technique called reverse transcriptase–loop-mediated isothermal amplification (RT-LAMP).

Currently, the technology used in many point-of-care tests (POCT) for diagnosing disease have significant downsides. Polymerase chain reaction (PCR) tests are highly accurate, but require expensive apparatus and skilled personnel, making them expensive and impractical in many situations. Lateral flow tests are very quick, but often compromise on sensitivity and specificity. In addition, methods for amplifying samples of nucleic acids (DNA or RNA) to produce enough genetic material to be analysed require thermal cyclers, which have a very high power consumption, making them expensive and impractical to use in areas with limited power.

“The technology could detect hepatitis B, hepatitis C, influenza A and HIV on a single chip, with an accuracy of 95%”

In contrast, the chip, developed by researchers from the Harbin Institute of Technology in China, uses a photothermal enzyme, meaning its activity can be driven by LED illumination or even sunlight focusing on the samples, making it much cheaper and more portable. The chip also detects samples within just 30 minutes, making it practical for use in healthcare settings.

The researchers demonstrated that the technology could detect hepatitis B, hepatitis C, influenza A and HIV on a single chip, with an accuracy of 95%. This could represent an exciting new technique for the instant detection of many diseases, especially in resource-limited areas.