By mimicking (模仿) the properties (特性) of spider silk, one of the strongest materials in nature, researchers from the University of Cambridge have created a plant-based, sustainable material which promises to replace plastic in many common household products.

Created by using a new approach for assembling plant proteins into materials which mimic silk on a molecular (分子的) level, the new material is as strong as many common plastics in use today. The energy-efficient method, which uses sustainable ingredients, results in a plastic-like film. Non-fading “structural” color can be added to the film, and it can also be used to make water-resistant coatings.

For years, Professor Tuomas Knowles from Cambridge has been researching the behavior of proteins. Much of his research has been focused on what happens when proteins misfold or “misbehave”, and how this relates to health and human disease, primarily Alzheimer’s disease. As part of the research, Knowles and his team became interested in why materials like spider silk are so strong when they have such weak molecular bonds (键). Having found that one of the key features that gives spider silk its strength is that the hydrogen bonds are arranged regularly in space and at a very high density, the researchers successfully replicated (复制) the structures found on spider silk by using soy protein isolate (SPI), a protein with a completely different composition.

“Other researchers have been working directly with silk materials as a plastic replacement, but they’re still an animal product. In a way we’ve come up with ‘vegan spider silk’— we’ve created the same material without the spider.”

“This is the culmination of something we’ve been working on for years, which is understanding how nature generates materials from proteins,” said Knowles. “We didn’t set out to solve a sustainability challenge — we were motivated by curiosity as to how to create strong materials from weak interactions.”

After the Covid-19 pandemic began early in 2020, Traverso and his colleagues turned their attention toward new ways to reduce interactions between potentially sick patients and health care workers. To that end, they worked with Boston Dynamics to create a mobile robot that could interact with patients as they waited in the emergency department. The robots were equipped with sensors that allow them to measure signs of life. The robots also carried an iPad that allowed for remote video communication with a health care provider.

This kind of robot could reduce health care workers' risk of exposure to Covid-19 and help to conserve the personal protective equipment that is needed for each interaction. However, the question still remained whether patients would accept this type of interaction.

In Traverso's study they were trying to tide that up and understand if the population accepts a solution like this one. The researchers first conducted a nationwide survey of about 1, 000 people, working with a market research company called YouGov. They asked questions regarding the acceptability of robots in health care, including whether people would be comfortable with robots performing not only classification but also other tasks such as planting a tube, or turning a patient over in bed. On average, the subjects stated that they were open to these types of interactions.

The researchers then tested one of their robots in the emergency department at Brigham and Women's Hospital last spring, when Covid-19 cases were flooding in Massachusetts. Fifty-one patients were approached in the waiting room and asked if they would be willing to participate in the study, and 41 agreed. These patients were interviewed about their symptoms via video connection, using an iPad cared by a log-like robot developed by Boston Dynamics. More than 90 percent of the participants reported that they were satisfied with the robotic system.

"For the purposes of gathering quick classification information, the patients found the experience to be similar to what they would have experienced talking to a person," Traverso says.

In 2019 air travel accounted for 2.5 percent of global carbon emissions, a number that could be more than doubled by 2050. While some airlines have started making up for their contributions to atmospheric carbon, significant cutbacks are still needed. Electric airplanes could provide the scale of transformation required, and many companies are racing to develop them. Not only would electric propulsion (推进) motors eliminate direct carbon emissions, they could reduce fuel costs by up to 90 percent, maintenance by up to 50 percent and noise by nearly 70 percent.

Cape Air, one of the largest regional airlines, expects to be among the first customers, with plans to buy the nine-passenger electric aircraft from Eviation. Cape Air’s CEO Dan Wolf has said he is interested not only in the environmental benefits but also in potential savings on operation costs. Electric motors generally have longer life spans than the hydrocarbon-fueled engines in his current aircraft; they need repairs at 20,000 hours versus 2,000.

Forward-propulsion engines are not the only ones going electric. NASA’s X-57 Maxwell electric plane, under development, replaces current wings with shorter ones that feature a set of distributed electric propellers (螺旋桨). On traditional jets, wings must be large enough to provide lift when a craft is traveling at a low speed, but the large surface area adds drag at higher speeds. Electric propellers increase lift during takeoff, allowing for smaller wings and overall higher efficiency.

For the foreseeable future, electric planes will be limited in how far they can travel. Today’s best batteries put out far less power by weight than traditional fuels: an energy density of 250 watt-hours per kilogram versus 12,000 watt-hours per kilogram for jet fuel. The batteries required for a given flight are therefore far heavier than standard fuel and take up more space. Approximately half of all flights globally are fewer than 800 kilometers, which is expected to be within the range of battery-powered electric aircraft by 2025.

Electric aviation faces cost and regulatory obstacles, but investors, corporations and governments excited by the progress of this technology are investing significantly in its development: some $250 million flowed to electric aviation start-ups between 2017 and 2019. Currently roughly 170 electric airplane projects are underway. Most electric airplanes are designed for private, corporate and commuter travel, but Airbus says it plans to have 100-passenger versions ready to fly by 2030.