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On July 22 (Monday), the main contents of the well-known foreign scientific website are as follows:

Science News website (www.sciencenews.org)

Light excitationSuperconductivityA new study has reignited the debate

superconductorBut since 2011, some scientists have claimed that certain materials can briefly exhibit superconductivity at temperatures far above the conventional limit when hit by intense, ultrashort laser pulses.

Previous studies have shown that cuprates temporarily change their reflectivity when exposed to light. This change means that the drop in resistance may last only a picosecond (a trillionth of a second). However, critics have argued that this change may be caused by other factors rather than superconductivity.

Physicist Andrea Cavalleri of the Max Planck Institute in Germany and his team recently reported in the journal Nature that the copper in the experiment released a molecule called a molecule when hit by light.magnetic field, they believe this is evidence of the Meissner effect of superconductivity. Nevertheless, the academic community has different degrees of acceptance of this conclusion and opinions are still divided.

Research had shown that light could destroy superconductivity, but the idea of ​​light-induced superconductivity was unexpected and controversial. So Cavaleri and his colleagues investigated the Meissner effect further. They focused on yttrium barium copper oxide (YBCO), a class of compounds that had previously shown signs of light-induced superconductivity.

The team used a gallium phosphide crystal next to YBCO to measure the magnetic field. They found that if YBCO becomes a superconductor, the Meissner effect will cause its internal magnetic field to be expelled. This will cause the magnetic field at the edge of the YBCO to increase in strength, as they observed.

Science Daily website (www.sciencedaily.com)

1. Cracking the code of hydrogen embrittlement: laying the foundation for better prediction of hydrogen embrittlement

When selecting materials for infrastructure projects, metals are often chosen for their durability. However, when metals are exposed to hydrogen-rich environments, they become brittle and fail. This phenomenon, known as hydrogen embrittlement, has puzzled researchers since the mid-19th century and is difficult to master due to its unpredictability. Recent research published in the journal Science Advances brings us one step closer to confidently predicting hydrogen embrittlement.

The study, a collaboration between researchers at Washington and Lee University and Texas A&M University, examined the crack formation process in Inconel 725, a nickel-based alloy known for its strength and corrosion resistance that is initially flawless and crack-free.

Several hypotheses have been proposed to explain the mechanism of hydrogen embrittlement. The results of this study show that one of the best-known hypotheses - hydrogen-enhanced local plasticity (HELP) - does not apply to this alloy.

The researchers found that plasticity (or irreversible deformation) is not uniform in the material, but localized in specific areas. The HELP hypothesis states that cracks originate in areas with the highest local plasticity. "To my knowledge, our study is the first to observe the location of crack initiation in real time and find that it does not start in the area of ​​highest local plasticity."

Tracking crack initiation in real time is crucial. When examining a sample after a crack has appeared, hydrogen has already escaped from the material, making it impossible to understand the mechanism that caused the damage.

The importance of this research is that it helps lay the foundation for better predictions of hydrogen embrittlement. As hydrogen may become a future clean energy alternative to fossil fuels, predicting this embrittlement becomes critical to prevent unexpected failures in a future hydrogen economy.

2. The causal structure determines that consciousness cannot exist in computer simulations

Can artificial intelligence develop consciousness? Dr. Wanja Wiese of the Second Institute of Philosophy at Ruhr-Universität Bochum in Germany thinks it is impossible. In a recent article published in the journal Philosophical Studies, Dr. Wiese examined the conditions required for consciousness to exist and put it in the context of the theory of consciousness.brainHe compared humans to computers. He pointed out that there are significant differences between humans and machines, especially in the organization of brain regions, memory and computational units. Dr. Wiese believes that "causal structure may be an important difference related to consciousness."

In his research, Dr. Wiese also cited the free energy principle proposed by British neuroscientist Karl Friston. This principle states that the processes that ensure the continued existence of a self-organizing system (such as an organism) can be regarded as a form of information processing. In the human body, this includes processes that regulate important parameters such as body temperature, oxygen content in the blood, and blood sugar. Similar information processing processes can also be implemented in computers, but the computer does not regulate its temperature or blood sugar level, but only simulates these processes.

The researchers believe that consciousness may be similar. If consciousness is beneficial to survival, then according to the free energy principle, the physiological processes that help the organism to maintain itself must retain traces left by conscious experience, which can be described as information processing processes called "computational correlates of consciousness." Although this is possible in computers, additional conditions may need to be met in order for computers to not only simulate but also replicate conscious experiences.

Therefore, in his article, Dr. Wiese analyzes the differences between how conscious organisms achieve the computational correlates of consciousness and how computers achieve it in simulations. He argues that most of these differences are irrelevant to consciousness. For example, unlike electronic computers, our brains are very energy-efficient, but this is unlikely to be a necessary condition for consciousness.

However, another key difference between computers and brains lies in their causal structure: in a traditional computer, data must first be loaded from memory to the central processor for processing, and then stored back to memory again. In the brain, there is no such separation, and the causal connections between various regions take different forms. Dr. Wiese believes that this may be one of the key differences between the brain and traditional computers in terms of consciousness.

Scitech Daily website (https://scitechdaily.com)

1. Not science fiction: Researchers have developed a metasurface tractor beam

Researchers at Australia's ARC Centre of Excellence for Translational Meta-Optical Systems (TMOS) have advanced the development of lightweight tractor beams that will transform non-invasive medical procedures. They have made significant progress in creating tractor beams enabled by metasurfaces. Capable of attracting particles towards them, these beams are inspired by fictional tractor beams from science fiction. In research published in the journal Acs Photonics, the team describes how they used a silicon metasurface to generate electromagnetic beams. Electromagnetic beams have previously been generated using bulky special light modulators (SLMs), but the size and weight of these systems have prevented the beams from being used in handheld devices. The metasurface is a layer of nano-patterned silicon that is just 1/2000 of a millimeter thick. The team hopes that this technology could one day be used to examine live tissue in a non-invasive way, without the risk of damaging surrounding tissue, as current methods, such as using tweezers, can do.

This particular electromagnetic beam has several advantages over previously generated electromagnetic beams, as the conditions required for the input beam are more flexible than previous beams, no SLM is required, and its size, weight, and power requirements are significantly lower than previous systems.

"The compact size and high efficiency of this device could lead to innovative future applications," the researchers said. "The ability to extract particles using metasurfaces could impact the field of biopsy by enabling less invasive methods that reduce pain."

2. Missing piece of the chronic pain puzzle? Newly discovered protein function

A research team at the Max Delbrück Center in Germany has discovered a new role for the protein PIEZO2 in promoting chronic pain hypersensitivity. The discovery offers a potential new avenue for pain medication and may shed light on why treatments focusing on voltage-gated sodium channels have performed poorly in clinical solutions. The study was published in Brain, a leading neurology journal.

The PIEZO2 protein forms ion channels in human sensory receptors. Previous studies have shown that ion channels are involved in transmitting touch sensations to the brain. People with "loss-of-function" mutations in the PIEZO2 gene are less sensitive to gentle touch or vibrations. In contrast, patients with "gain-of-function mutations" in PIEZO are often diagnosed with complex developmental disorders. But whether gain-of-function mutations are associated with mechanical hypersensitivity has never been proven.

To study this connection, the researchers created two so-called "gain of function" mice, each carrying a different version of the mutant PIEZO2 gene. Using electrophysiological methods, the researchers measured the electrical activity of sensory neurons isolated from the genetically modified mice. They found that in addition to sensitizing touch receptors as expected, the PIEZO2 gene mutation also made nociceptors - neurons that detect painful mechanical stimuli - significantly more sensitive to mechanical stimuli.

Additionally, the researchers found that nociceptors are activated by mechanical stimulation, which is usually light touch.

This study is the first to link a gain-of-function mutation in the PIEZO2 gene to a pain receptor. The findings suggest that a specific aspect of the PIEZO2 channel opening mechanism could be targeted by new pain drugs.