Hot topic review | Dead crabs cannot be eaten; colleges and universities give out mooncakes for free?

"Hotspot Review | Major Technology Events of the Week" is a new column with pictures and texts launched by Academic Headlines, which aims to help readers quickly understand the hot technology news of the past week. Due to the limited space (and knowledge), everyone is welcome to add more~

Hi, my lovely “academic bacteria”, I am your lovely Academic King.

Last week was another "last week" that has passed.

Last week, we celebrated the Mid-Autumn Festival and Teachers’ Day on the same day. The next coincidence will be in 2041.

This Mid-Autumn Festival, you must have eaten a lot of crabs. Crabs are delicious, but don't eat those that died before being cooked , because eating dead river crabs may cause Bacillus cereus and Vibrio parahaemolyticus food poisoning;

A mixed news is that after students from the University of Science and Technology of China received a phishing email deliberately released by the school offering "Free Mooncakes for Mid-Autumn Festival", some of them were directly attacked due to their lack of relevant cybersecurity knowledge, while others were able to identify the risk in time and even launched a DDOS attack on the phishing website. It seems that cybersecurity training is very important~

But... In addition to these, what other hot news were there last week? Let's take a quick look at them together:

Experts answer: Why has the COVID-19 outbreak in China been recurring recently?

Tsinghua team achieves world's highest efficiency in flexible perovskite solar cells

A microwave oven is the key to 2-nanometer chip manufacturing?

Scientists have made new discoveries in the lunar soil of Chang'e 5

MIT new research: AlphaFold is not much better than random guessing

Progress in the study of massive star formation

When the indestructible cockroach turns into a "cyborg cockroach" ...

We are in a new geological era: the Anthropocene

· The Yangtze sturgeon is not extinct? Extinction in the wild does not mean that it does not exist in the wild

Tsinghua team reveals carbon reduction synergy benefits of China's clean air actions

Research shows that the incidence of cancer in people under 50 years old has increased dramatically worldwide . The following is a detailed version of the text, which can be read selectively.

1.Why can’t we eat dead crabs?

In this season, crabs are an indispensable delicacy on people's tables.

Some people buy cheaper dead crabs to eat because crabs are too expensive, and some unscrupulous merchants directly sell dead crabs as live crabs. However, some dead crabs cannot be eaten, and eating them by mistake may cause poisoning, such as river crabs, which are commonly known as hairy crabs.

Experts say that river crabs have high levels of free amino acids and nitrogen compounds, and their meat is relatively loose, providing favorable conditions for the growth of microorganisms. In addition, river crabs grow in silt, and the living environment is suitable for the growth of microorganisms, which leads to a high base number of total bacterial colonies inside and outside the fresh river crabs. Once a river crab dies, the content of microorganisms in its body will increase rapidly . Therefore, even if the crab has just died, it should not be eaten.

(Source: Pixabay)

Experts from the Chinese Academy of Fishery Sciences pointed out that crabs cannot be eaten after they die, mainly because the microorganisms in their bodies multiply rapidly, causing the colony count to exceed the standard. Such hairy crabs cannot be completely eliminated by home cooking methods . Eating dead crabs may cause food poisoning caused by Bacillus cereus and Vibrio parahaemolyticus.

Source: CCTV.com

2. Expert answer: Why has the COVID-19 outbreak in my country been recurring recently?

On September 9, 2022, in response to the recent situation of the new coronavirus pneumonia epidemic in China, Wu Zunyou, chief epidemiologist of the Chinese Center for Disease Control and Prevention, wrote an article stating that the recent ups and downs of the new coronavirus pneumonia epidemic in China are mainly due to the surrounding environment and mutant viruses .

In the past four waves of the COVID-19 epidemic, except for the second wave of the Delta variant strain originating from India, which was most serious in Southeast Asia, the other three waves were centered in the Americas and Europe. Regardless of the number of cases and deaths, these two regions combined accounted for more than half of the world's total.

The center of the global fifth wave of COVID-19, which is still at its peak, has shifted to the Western Pacific region. As a member of the Western Pacific region, China has been affected by the severe epidemic in neighboring countries and regions, which has put tremendous pressure on my country to "prevent imported cases from abroad." This is the main external reason for the recent severe epidemic situation in my country.

On the other hand, the emergence of the Omicron variant has made hidden transmission more common and increased the difficulty of prevention and control. As to what caused some people infected with the new coronavirus to have alternating negative and positive nucleic acid test results, it is not clear at present and further research is needed. The role of this alternating negative and positive phenomenon in "hidden transmission" also needs further research.

Source: Weibo @吴尊友ChinaCDC

3. Colleges and universities give away mooncakes for free? The result is unexpected...

Recently, a student from the University of Science and Technology of China posted on social media that he received an email about "receiving free mooncakes during the Mid-Autumn Festival", but after filling out the information, he did not receive the mooncakes ...

According to Upstream News, on the morning of September 8, Mr. Cheng from the Network Information Center of USTC stated that this was actually an official "activity" and "the first phishing email drill in the entire school."

Teacher Cheng revealed: "At 5:30 pm on September 7, we took advantage of the fact that everyone was relaxed after school and sent more than 40,000 emails in one hour. These emails were all targeted at teachers and students on the campus of USTC, including more than 30,000 students and more than 6,000 faculty and staff. As a result, many people were fooled. From 6:30 to 7:30 pm, the number of visitors to the phishing website reached 8,000, which greatly exceeded our expectations."

Teacher Cheng also said: "During this drill, many students filled out real information, and the largest number of them were freshmen in their first year of undergraduate studies. They are relatively lacking in relevant cybersecurity knowledge , so we will focus on providing them with cybersecurity training in the next step."

"We saw in the background that some students submitted false information, which shows that they have a sense of prevention. Some students also launched a DDOS attack on our phishing website. They also shared in the QQ group that the free shooting range has come and it would be a waste if we don't shoot. At that time, the phishing website was paralyzed. However, before this exercise, when we asked Tsinghua University for advice, they reminded us that there would definitely be student attacks, so we also took preventive measures, so in the end there was no loss of the server."

In order to prevent the phishing email drill from becoming a case of "crying wolf" and causing teachers and students to lose trust in official emails, Cheng said they adjusted the plan and left many "tells", such as email abbreviations and contact numbers. "If you are careful enough, you can see many 'tells'."

Source: Science and Technology Daily

4. Tsinghua team achieves the world's highest efficiency in flexible perovskite solar cells

Recently, Yi Chenyi's research group from the Department of Electrical Engineering at Tsinghua University proposed a strategy to reduce defects and lattice microstress in perovskite films through multifunctional additives, achieving a world record of 23.6% photoelectric conversion efficiency (PCE) for single-junction flexible perovskite solar cells .

Organic-inorganic hybrid perovskite materials have the advantages of excellent light absorption performance and low processing cost. Flexible perovskite solar cells prepared on flexible substrates have the advantages of being light, shapeable, and having a high power-to-weight ratio. They have broad application prospects in wearable electronic devices, unmanned aerial vehicles, photovoltaic building integration and other fields, and have therefore received widespread attention from academia and industry.

How to further improve the photoelectric conversion efficiency and bending resistance of flexible devices is the key to their practical application.

In this study, the research team designed a succinate additive to be added to the perovskite precursor solution to improve the quality of perovskite films and the performance of perovskite solar cells. The perovskite solar cells prepared by this method have excellent photoelectric performance, and the photoelectric conversion efficiency of rigid cell devices under AM1.5G standard illumination is as high as 25.4%.

The flexible devices prepared on the flexible substrate achieved a maximum photoelectric conversion efficiency of 23.6% (certified efficiency 22.5%), which is the highest efficiency record of single-junction flexible perovskite solar cells reported to date.

The comprehensive improvement in the efficiency and bending resistance of flexible devices shows a good prospect for the practical application of flexible perovskite solar cells.

Source: Tsinghua University

Paper link:

https://www.sciencedirect.com/science/article/pii/S2666675822001060

5. A microwave oven is the key to 2-nanometer chip manufacturing?

A Cornell University research team and its collaborators have used a modified microwave oven to overcome a major challenge facing the semiconductor industry : using traditional methods to heat highly doped materials has made it impossible to produce semiconductors with stable performance.

Semiconductor maker TSMC thought microwaves could theoretically be used to activate excess dopants. But, just as a household microwave oven sometimes heats food unevenly, previous microwave annealing setups tended to create “standing waves” that prevented uniform activation of the dopants.

To this end, TSMC worked with Hwang to selectively control where the standing waves occur through a modified microwave oven, thereby activating the dopants just right without overheating or damaging the silicon crystal.

In recent years, chipmakers have begun experimenting with a new structure in which transistors can be stacked horizontally. Microwave annealing, which makes more doped materials possible, is key to making the new structure possible.

The research team said their work is helping to manufacture the next generation of mobile phones, computers and other electronic products , and is expected to be used to manufacture semiconductor materials and electronic products produced around 2025, and even help chip manufacturers such as TSMC and Samsung shrink chip size to 2 nanometers.

Paper link:

https://aip.scitation.org/doi/10.1063/5.0099083

6. Scientists have made new discoveries in the lunar soil of Chang'e 5

Research on lunar soil samples from Apollo and other sources suggests that nanophase iron particles in lunar soil are mainly formed by vapor deposition caused by meteorite and micrometeorite bombardment or reduction caused by H+ injection, the main component of solar wind. The former has been verified by a large number of lunar soil sample analyses and simulation experiment results and is widely recognized by the academic community, while the latter has so far lacked sufficient direct evidence and mechanism explanation.

The Chang'e-5 lunar soil is the first lunar return sample obtained by mankind in 44 years. It has a different sampling location, mineral composition and evolutionary history from the Apollo and Luna samples, so it may provide new evidence for exploring the formation mechanism of elemental metallic iron.

The Institute of Geochemistry, Chinese Academy of Sciences, in collaboration with Kunming University of Science and Technology, conducted an in-depth and detailed analysis of the fayalite particles in the lunar soil powder (CE5C0200YJFM00302) collected from the Chang'e-5 surface, and found reliable evidence of elemental metallic iron formed by disproportionation reactions in secondary impact craters at the submicron scale.

At the same time, theoretical calculation results show that the formation speed of the secondary impact crater is less than 3.0 km/s. The discovery and confirmation of the disproportionation reaction-induced nano-scale elemental metallic iron has revolutionized the academic community's existing understanding of the formation mechanism of elemental metallic iron in lunar soil for decades.

In addition, since low-speed impacts are widespread in the solar system, they have reference and reference significance for exploring the formation mechanism of elemental metallic iron in the surface soil of the moon, especially the permanent shadow regions at the poles, asteroids, and solid celestial bodies in the outer solar system.

Source: Institute of Geochemistry, Chinese Academy of Sciences

Paper link:

https://www.nature.com/articles/s41550-022-01763-3

7. MIT new research: AlphaFold is not much better than random guessing

In July this year, DeepMind and EMBL-EBI used AlphaFold to predict almost all known proteins on Earth, which was a major leap in the field of biology and sparked heated discussions on social media at home and abroad. However, scientists in the field of life sciences, who are "insiders", have mixed opinions on the achievements of AlphaFold.

Recently, a research team from MIT, Harvard University and the Broad Institute found in a new study that AlphaFold did not perform well in drug discovery. "In fact, their predictions were not much better than chance."

Figure | Complex protein networks in cells

In this work, the research team used protein structures generated by AlphaFold to explore whether existing models can accurately predict the interaction between bacterial proteins and antibacterial compounds.

Such simulations have been successfully used in studies that screen large numbers of compounds against a single protein target to identify those that achieve the best binding. However, when they tried to screen multiple compounds against many potential targets, AlphaFold's predictions were much less accurate.

In addition, the team found that by comparing the predictions generated by the model with the actual interactions of 12 essential proteins obtained in laboratory experiments, the model's false positive rate was similar to its true positive rate, suggesting that the model was unable to consistently identify true interactions between existing drugs and their targets.

The research team believes that "the structure predicted by AlphaFold seems to be roughly the same as the experimentally determined structure, but if we are to use AlphaFold effectively and widely in drug discovery, we need to do better in molecular docking modeling. "

Paper link:

https://www.embopress.org/doi/full/10.15252/msb.202211081

8. Progress in the study of massive star formation

During the star formation process, the conversion of atomic gas into molecular gas and the driving source of the molecular outflow are difficult to study.

Recently, the Purple Mountain Observatory and the National Astronomical Observatory of the Chinese Academy of Sciences, as well as the Three Gorges University and Hunan University of Arts and Science have cooperated to combine the FAST HI spectral line data with the molecular spectral line data of the 13.7 m millimeter-wave telescope at the Qinghai Observatory of the Purple Mountain Observatory, and use the new baseline calibration algorithm independently developed by the team. They have made a series of progress in the study of massive star formation , demonstrating the potential of collaborative observational research between FAST and the 13.7 m millimeter-wave telescope.

The magnetic centrifugal jet theory predicts that the molecular outflow is driven by high-speed HI winds, but this theory has not been proven by observations because it is challenging to detect HI winds. In low-mass star-forming regions, HI winds can drive molecular outflows. However, in high-mass star-forming regions, it is unclear whether HI winds can drive molecular outflows, where atomic hydrogen comes from, and how it is related to molecular hydrogen.

In order to detect HI stellar winds, a new baseline calibration algorithm, FFTEEC, was developed. This algorithm can minimize baseline noise and make the final spectral line sensitivity close to the theoretical level. This algorithm makes full use of the high sensitivity advantage of FAST, making FAST a powerful tool for detecting HI stellar winds.

In addition, researchers detected HI stellar winds in this region for the first time and found that HI stellar winds in massive star-forming regions are likely to drive molecular outflows, similar to the situation in low-mass star-forming regions. Further studies have shown that the abundance of HI in the stellar wind is consistent with the abundance of HINSA, which indicates that HINSA will become a physical bridge for exploring HI stellar winds and molecular outflows, and that atomic hydrogen in HI stellar winds is more likely to inherit the parent molecular cloud.

Source: Purple Mountain Observatory, Chinese Academy of Sciences

9. When the indestructible cockroach transforms into a "cyborg cockroach"...

Cockroaches, commonly known as "xiaoqiang", are a kind of strange creatures that everyone hates and wants to get rid of as soon as possible.

However, the tiny cockroach can also be used in a big way , such as being deployed in search and rescue missions or investigating dangerous places. However, the need for remote control and long-term endurance has always been an unresolved problem. Now, this idea may be about to become a reality.

A research team from the RIKEN Cluster for pioneering Research (CPR) and its collaborators have designed a system that can create remote-controlled cyborg cockroaches.

Figure｜Schematic diagram of a semi-mechanical cockroach.

It is reported that the system is equipped with a miniature wireless control module that can be charged by solar energy, which can achieve self-powering, and the ultra-thin electronic devices and flexible materials can enable the cyborg cockroach to move freely.

The research team believes that the advent of cyborg cockroaches may make it possible to use cyborg insects in real life.

Paper link:

https://www.nature.com/articles/s41528-022-00207-2

10. We are in a new geological epoch: the Anthropocene

In recent decades, human activities have disturbed the natural environment and have had a significant negative impact on humans themselves. Some scholars have proposed that the state of the Earth system today is different from the Holocene and should be in a new geological era - the "Anthropocene" , emphasizing that the impact of human activities on the Earth system is comparable to or even exceeds that of natural processes.

As human activities gradually intensified, the Earth system began to undergo accelerated changes on a global scale in the mid-20th century (around 1950 CE). This period is called the "Great Acceleration", and the International Anthropocene Working Group recommends this period as the start of the "Anthropocene". However, there is still controversy in the academic community about the start of the "Anthropocene", mainly because humans had already caused a great degree of interference to the Earth's environment through agricultural production, mineral development, settlement construction, etc., especially in China's monsoon region.

The researchers concluded that China's development history over the past 2,000 years can be divided into four historical stages :

(1) Between 2.0 and 1.0 ka, several proxy indicators (including woody pollen ratio, magnetic susceptibility, organic carbon isotopes, and lead content) at the core area sample points began to deviate significantly from the natural background due to the influence of human activities. Different sample points began to deviate at different times, indicating that human activities had local enhanced characteristics.

(2) From 1.0 ka to 1950 CE, the above indicators of the core area samples deviated significantly from the natural background, indicating that human activities in the core area had regionally enhanced, while the proxy indicators of the marginal areas remained roughly in the natural state during the same period.

(3) From 1950 to 1980 CE, organic carbon, total nitrogen and their isotopes changed significantly, with no significant difference between the core and peripheral areas, indicating that human activities in the entire region of China increased significantly. The changes in these indicators were mainly affected by agricultural and industrial activities and population growth.

(4) After 1980 CE, the changes in the above indicators further intensified, and the contents of lead, black carbon, and polycyclic aromatic hydrocarbons increased sharply, reflecting the rapid development of China's industry and the modernization of agriculture.

Figure: Four historical stages of the development of human activities in China

Among them, the synchronous changes in the core and peripheral areas of China in 1950 CE coincide with the time of the global "Great Acceleration". The boundaries of the above four periods can correspond to major historical events, and also correspond to major changes in productivity or production relations. The study suggests that transportation networks and industrialization play an important role in the regional impact of human activities.

Source: Institute of Earth Environment, Chinese Academy of Sciences

Paper link:

https://linkinghub.elsevier.com/retrieve/pii/S0048969722052482

11. Is the Yangtze sturgeon not extinct? Extinction in the wild does not mean that it does not exist in the wild

On July 21, 2022, the World Conservation Union (IUCN) updated the Red List of Threatened Species. The list shows that the Yangtze River endemic species, the Chinese sturgeon (Psephurus gladius), has become extinct, and the Yangtze River sturgeon (Acipenser dabryanus) is extinct in the wild.

However, a Yangtze sturgeon was recently trapped in a puddle on the beach at Luohuozhou Beach in Tuanfeng County, Hubei Province. After being rescued by enthusiastic citizens and fishery staff, it was successfully released into the Yangtze River. Some netizens are confused, does extinction in the wild not mean extinction?

In response to this matter, experts said that the Yangtze sturgeon discovered recently were artificially released individuals, which is a common situation and has nothing to do with the previously announced extinction of Yangtze sturgeon in the wild.

"The Yangtze sturgeon is not extinct, but extinct in the wild. That is to say, the Yangtze sturgeon no longer reproduces naturally in nature, not that there are no Yangtze sturgeons in the wild. This is a misunderstanding . Every year, they are released into the wild, so there are still some individuals in the wild. If the Yangtze sturgeon can reproduce naturally, the label of extinction in the wild can be removed."

Wei Qiwei also introduced that since the artificial release of Yangtze sturgeons in 2007, there have been many cases of accidental capture every year. The Yangtze River has not been closed for fishing, and many fish that come down from the upper reaches are hunted before they grow up. Yangtze sturgeons have not reproduced naturally, and researchers hope that through artificial release, after a few years of wild growth, the Yangtze sturgeons will eventually reproduce naturally.

Source: Red Star News

12. Tsinghua team reveals carbon reduction synergy benefits of China’s clean air actions

In recent years, China's clean air actions have promoted a significant reduction in air pollutants, and their impact on climate change has received widespread attention. Research on the impact of clean air actions on climate change mainly focuses on climate factors such as changes in radiative feedback caused by air pollution. Currently, only a few studies have calculated the carbon synergistic reduction benefits brought about by the implementation of clean air actions in key areas. No research has yet quantified the contribution of China's clean air actions to the synergistic reduction of national carbon emissions since the implementation of the "Air Pollution Prevention and Control Action Plan" in 2013 , and conducted in-depth analysis from the perspective of measures.

To address this issue, Zhang Qiang's research team from the Department of Earth System Science at Tsinghua University reviewed and sorted out five synergistic emission reduction measures in China's Clean Air Action, including elimination of obsolete production capacity, rectification of industrial coal-fired boilers, clean replacement of civilian scattered coal, rectification of "scattered and messy" and elimination of yellow-label vehicles and old vehicles. Based on the independently developed Chinese multi-scale emission inventory model, they further constructed a measure-level synergistic emission reduction effect assessment technology, and quantified the changes in energy supply and consumption structure brought about by various synergistic emission reduction measures based on the actual implementation of each province, and finally calculated the carbon emission reduction synergistic benefits generated by the Clean Air Action.

Figure | Coordinated reductions in carbon dioxide emissions from the five coordinated measures in China's Clean Air Action between 2013 and 2020

Research shows that China's clean air action involves measures to control total energy consumption, adjust energy structure and improve energy efficiency. It has promoted the transformation of China's energy system by eliminating or upgrading inefficient, highly polluting and backward combustion facilities, reduced fossil fuel consumption and produced significant carbon synergy reduction benefits.

In addition, China's clean air action has promoted the process of replacing inefficient and high-carbon energy facilities with clean and efficient energy facilities, accelerating energy efficiency improvement, energy structure transformation and industrial structure transformation. This experience of coordinated emission reduction also provides a possible transition plan for developing countries facing air pollution problems to transform to a low-carbon development path.

In the future, China still needs to further optimize its energy system and economic structure to promote the realization of the "carbon peak" and "carbon neutrality" goals, and when designing emission reduction policies, it should focus on relevant measures with significant carbon synergistic emission reduction benefits.

Source: Tsinghua University

Paper link:

https://www.nature.com/articles/s41467-022-32656-8

13. Research shows that the incidence of cancer in people under 50 is rising sharply worldwide

A study conducted by American scientists shows that the incidence of early-onset cancers (cancers diagnosed before the age of 50, including breast cancer, colon cancer, esophageal cancer, kidney cancer, liver cancer and pancreatic cancer) has increased sharply worldwide since 1990.

The researchers found that the risk increases with each generation . For example, people born in 1960 have a higher risk of developing cancer before age 50 than those born in 1950. The researchers predict that the risk will continue to climb in future generations.

Early life exposures, including diet, weight, lifestyle, environment and microbiota, have changed significantly over the past few decades. Therefore, the research team hypothesized that factors such as Western diet and lifestyle may be responsible for the prevalence of early-onset cancer.

Since the 1950s, risk factors such as highly processed foods, sugary drinks, and sedentary lifestyles have increased significantly, and researchers speculate that this is related to changes in the microbiome. "Of the 14 cancer types we studied, eight are related to the digestive system," the researchers said. "Diet directly affects microbial composition, ultimately affecting disease risk and outcomes."

Source: China Science Daily

Paper link:

https://www.nature.com/articles/s41571-022-00672-8