Black plastic contains drugs, causing panic? The source is that the relevant research missed a zero | Technology Weekly

Compiled by Zhou Shuyi and Pingsheng

Algorithms can "smell" the aroma and origin of whiskey

Researcher holding a whiskey. | Fraunhofer IFP

A study published in Communications Chemistry on December 19 used a machine learning algorithm to determine whether a glass of whiskey was produced in the United States or Scotland, and even identified the five strongest aromas of each whiskey with higher accuracy than human experts.

The aroma of whiskey is a mixture of many complex aroma compounds. Therefore, it is very difficult to evaluate the aroma characteristics of whiskey based on its molecular composition alone. Usually, a human expert panel is required, which requires a lot of time, money and training investment. In addition, human evaluation is subjective and there is often disagreement among participants.

The researchers developed two algorithms, including a molecular odor prediction algorithm OWSum and a neural network algorithm, to evaluate the molecular composition of seven American whiskeys and nine Scotch whiskeys. The molecular composition data came from existing results of gas chromatography and mass spectrometry, two techniques that can separate and identify components in a mixture. The authors used the algorithm to identify the country of origin and the five strongest aroma characteristics of each whiskey, and then compared the algorithm results with those obtained by a panel of 11 experts.

Research shows that OWSum can identify whether a whiskey is produced in the United States or Scotland with an accuracy of over 90%. Menthol and citronellol are most closely associated with American whiskey, while methyl decanoate and heptanoic acid are most closely associated with Scottish whiskey. OWSum identifies caramel as the most characteristic aroma of American whiskey, while apple, solvent, and phenolic (often described as smoky or medicinal) are considered characteristics of Scottish whiskey. The average performance of these two algorithms is more accurate and stable than that of human experts.

Long-term intermittent fasting may cause hair loss

How can we have the best of both worlds? We should not let down the Buddha or the beloved. Those who do intermittent fasting for a long time may have to make some choices between hair and weight. A study published in Cell on December 14 pointed out that intermittent fasting can induce apoptosis of activated hair follicle stem cells, thereby inhibiting hair follicle regeneration and hair growth.

At present, intermittent fasting has become a healthy fashion around the world. For example, the most popular 16/8 time-restricted eating method is to eat only 8 hours a day and not eat for the remaining 16 hours. Other common intermittent fasting methods include fasting every other day and fasting two days a week. Many studies have shown that intermittent fasting not only helps to lose weight, but also improves metabolic health, reduces inflammation in the body, improves brain concentration, and prolongs life. However, its negative effects on the body are rarely mentioned.

The research team explored the response of hair follicle stem cells (HFSC) to intermittent fasting. In skin tissue, HFSCs are activated periodically, and hair follicles undergo periodic growth, regeneration, and resting phases, thereby continuously producing new hair. The research team first shaved the mice's original hair, and then designed two common intermittent fasting regimens for these mice-16/8 restricted feeding (TRF) and alternate-day fasting (ADF, alternating 24-hour fasting and 24-hour unlimited feeding), and used a normal diet (AL) as a control group. They found that after 96 days, the hair of mice in the normal feeding group was restored to its original state, while the 16/8 restricted feeding group and the alternate-day fasting group only restored hair in some areas, and it appeared sparse. This shows that intermittent fasting has a substantial inhibitory effect on the regeneration of hair follicles in mice.

Comparison of hair recovery in three groups of mice | Westlake University

Further studies have shown that intermittent fasting can selectively induce apoptosis of activated HFSCs to inhibit hair follicle regeneration. However, this inhibitory effect on hair follicle regeneration is not related to the calorie reduction, circadian rhythm changes, and mTORC1 cell nutrient sensing mechanism caused by intermittent fasting; instead, it is positively correlated with the length of fasting time. Intermittent fasting activates cellular communication between the adrenal glands and dermal adipocytes, triggering the rapid release of free fatty acids (FFA) into the niche microenvironment, thereby disrupting the normal metabolism of HFSCs and increasing their cellular reactive oxygen species (ROS) levels, ultimately leading to oxidative damage and cell apoptosis.

To determine whether intermittent fasting affects hair growth in humans, the research team also conducted a randomized clinical trial involving 49 healthy young adults who were randomly assigned to 16/8 time-restricted eating (TRD), energy-restricted diet (ERD), and normal diet (ND). The results showed that the average hair growth rate in the TRD group decreased by 18% compared with the control group, indicating that the effects of intermittent fasting on HFSC and hair growth also exist in humans.

Researchers said that from an evolutionary perspective, for human ancestors, perhaps being full was an accident, and hunger was the norm. Faced with the reality of hunger and satiety, life has developed sophisticated coping strategies. Even in the same skin tissue, epidermal stem cells and hair follicle stem cells have different ways of survival. Intermittent fasting seems to trigger an ancient brake mechanism, suspending the regeneration of some tissues and organs in the body to adapt to fluctuations in food supply.

Black plastic contains drugs, causing panic? The source is that the relevant research missed a zero

On December 15, the environmental science and engineering journal Chemosphere issued an erratum, saying that in a study published in September on the release of toxic flame retardants from black plastics, it missed a zero in the calculation and mistakenly believed that black plastic household products would cause the human body to ingest toxic flame retardants close to the safety limit. This study had previously attracted widespread attention and was reported by the media with headlines directly pointing out that black plastic threatens human health.

Decabromodiphenyl ether (BDE-209) is a brominated flame retardant widely used in electronics that is reproductive, developmental, endocrine and neurotoxic. Black plastic used in everyday household items, including kitchenware, takeaway containers, toys and hair accessories, may contain this toxic substance, partly made from recycled electronic waste.

The researchers analyzed how much BDE-209 is released and enters the human body during cooking from black plastic kitchen utensils. They tested 203 black plastic household products, including 109 kitchen utensils, 36 toys, 30 hair accessories, and 28 food utensils. The results showed that 14 of them contained BDE-209; the median daily exposure per person that may be caused by black plastic kitchen utensils is 34,700 ng. To measure whether this amount is safe, the paper compares it with the safety upper limit given by the US Environmental Protection Agency (EPA) (7,000 ng per kilogram of body weight per day). Based on an adult weight of 60 kg, the paper calculated the safety upper limit to be 42,000 ng, and 34,700 ng is clearly close to this upper limit.

This sounds pretty dangerous. But the problem is that 60 times 7,000 is not 42,000, but 420,000. As a result, the exposure is actually less than 1/10 of the safe upper limit. Joe Schwarcz, director of the Office of Science and Society at McGill University in Canada, pointed out this error. "I pay attention to everything about plastics. This is one of my specialties." He said in an interview, "I am good at math."

In the errata, the authors wrote: "We miscalculated the reference dose for a 60-kg adult by writing 420,000 ng per day instead of 420,000 ng per day. Therefore, we stated that we revised 'the calculated daily intake will be close to the US reference dose for BDE-209' to 'the calculated daily intake is still an order of magnitude lower than the US reference dose for BDE-209'. We regret this error and have corrected it in the paper." However, the authors believe that the error does not affect the overall conclusion of the paper. Megan Liu, the corresponding author of the paper, said in an interview that this was a "typographical error" and insisted that flame retardant pollution is a strong concern and that it is still recommended to avoid the use of black plastic kitchen utensils as much as possible.

On December 16, the day after the errata was released, the academic publishing data company Clarivate removed Chemosphere from SCI on the grounds that "editorial quality did not meet standards."

Joe Schwarcz said that using "nanograms" as a unit is easy to exaggerate the data, and it would be more reasonable to use the more common "micrograms". "This is very common in scientific literature, especially those that try to draw people's attention to a certain toxin." He said, "All of this is certainly worth paying attention to, but you have to be careful, you have to make sure your numbers are correct before scaring people."

The first ancient magnetic field information on the far side of the moon

In a study published in Nature on December 20, Chinese scientists used samples from the far side of the moon brought back by Chang'e-6 to obtain the first paleomagnetic field information from the far side of the moon, filling the data gap in the evolution of the lunar magnetic field in the middle and late stages. By analyzing the magnetic field information recorded in the samples about 2.8 billion years ago, the research team found that the intensity of the lunar magnetic field may have rebounded during that period, which is different from the previous belief that the lunar magnetic field dropped sharply about 3.1 billion years ago and has been in a low-energy state. This study fills a billion-year gap in the lunar paleomagnetic field record and provides the first paleomagnetic field measurement results from the far side of the moon.

The movement of the conductive fluid in the Earth's liquid outer core is like a "generator". The magnetic field it generates wraps around the Earth like a protective umbrella, shielding cosmic rays, protecting the Earth's atmosphere and water and other habitable elements, and forming an environment suitable for the reproduction of life. Studies have shown that the Moon no longer has a global dipole magnetic field, but it once had a "magnetic field generator" similar to that of the Earth.

The magnetic field record of Chang'e 6 basalt samples reveals the existence of a relatively active lunar magnetic field generator 2.8 billion years ago | Chinese Academy of Sciences

The scientific community previously believed that the moon had a relatively active magnetic field between 4.2 billion years ago and 3.5 billion years ago, with an intensity close to the current level of the Earth's magnetic field. The magnetic field dropped sharply about 3.1 billion years ago, and has been in a low-energy state since then. However, the previously published data on the strength of the lunar ancient magnetic field are mainly concentrated in 3 billion years ago, and data on the mid- and late-stage evolution of the lunar magnetic field have been lacking for a long time. The magnetic field information recorded by the Chang'e-6 lunar samples comes from about 2.8 billion years ago. Researchers conducted magnetic research on four millimeter-scale basalt rock chip samples and found that the lunar magnetic field rebounded about 2.8 billion years ago, which is significantly different from previous cognition. The study believes that the reason for the rebound may be that the main energy source of the "lunar magnetic field generator" changed about 2.8 billion years ago, or the initial driving mechanism was strengthened again. The researchers said that the team will conduct further research on the "lunar magnetic field generator" on this basis in the future.

US FDA updates health food standards: white bread and sweetened yogurt are not healthy

On December 19, the U.S. Food and Drug Administration (FDA) announced that it would redefine its standards for healthy foods. Only foods that meet the standards can be labeled "healthy" on the packaging to help consumers develop good eating habits. FDA data shows that more than 75% of Americans do not consume enough dairy products, fruits and vegetables, 77% consume too much saturated fat, 63% consume too much added sugar, and 90% consume too much sodium.

The FDA website announced that day that foods that can be labeled "healthy" must meet the following conditions: contain at least one type of food recommended by the U.S. Dietary Guidelines, such as fruits, vegetables, grains, skim or low-fat dairy products, and protein foods; and the content of added sugar, saturated fat, and sodium in the food does not exceed the standard. As for the specific amount of recommended food types or related ingredients that should be contained in the food, it varies depending on the specific product.

New healthy foods in the new regulations | FDA

According to the Associated Press, this is the first time that the United States has set a limit on the amount of added sugar in food that is circulated domestically. According to the new standard, some foods will not be able to be labeled "healthy" on the packaging as before, such as white bread, yogurt with too much sugar, cereals and fruit mixed drinks. Avocados, olive oil, salmon, eggs and some mixed nuts will be among the healthy foods, and even plain water can be labeled "healthy". The above new standards will take effect within 2 months, and relevant food manufacturers must make corresponding adjustments in a timely manner.

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