Every 40 seconds, someone in the US has a heart attack. Of course, this statistic applies only to humans. But what about other animal — do they also experience this condition?

A heart attack occurs when a blood vessel (血管) distributing oxygenated blood to the heart gets blocked and a piece of heart tissue dies from the deprivation of oxygen, according to Flavio Fenton, a professor of physics who studies both human and other animal species’ hearts. “Since animals’ hearts are very similar,” Fenton said, “most animals hearts, in principle, could have heart attacks.”

But that’s not what happened. For instance, heart attacks occur very rarely in dogs. Even the chimps, which are not only closely related to humans but also share similar risk factors for heart disease, do not have heart attacks. Even in mice and rabbits that are genetically modified to have high cholesterol (胆固醇) and blood fats for the purpose of inducing atherosclerosis and other human diseases, actual heart attacks rarely occur, according to a 2009 paper.

Despite previous reports that other animals mostly don’t have heart attacks, the truth is that there haven’t been a lot of experiments investigating this question. “You can observe that an animal has suddenly died, but very rarely would you actually look for the cause of it. We just don’t know whether they suffer heart attacks,” said Tomasz Owerkowicz, a physiologist at California State University.

But based on heart structures, researchers can make predictions about which creatures are most likely to have heart attacks. Owerkowicz and Fenton are doing such experiments on alligators (短吻鳄). “In their heart, you find the vessels; and they have spongy (海绵状的) tissues, around which there’s a lot of blood, not necessarily coming from the vessels,” Fenton said.

According to the researchers’ experiments so far, alligators don’t have heart attacks. The alligator’s heart tissue had no signs of cell death, Fenton added.

COVID-19(新冠病毒) is a threat to the very people fighting it-nurses, doctors, and other first responders, who are exposed to infected patients. Now, a team has developed two devices(设备) that could reduce their risks by sucking away infectious bacteria: a helmet to be worn by a patient,and a small tent in which a patient could be protected. The inventors hope they'll reduce the deaths among healthcare workers.

Negative-pressure rooms have been used in hospitals since the 1980s to keep airborne bacteria from spreading.But Nathan Haas says such rooms cost about$12,000. He and his colleagues wanted to develop a cheaper way to create a negative pressure environment for patients.The new devices could lower the need for negative-pressure rooms,which are rare in many parts of the world,according to Haas.

The helmet can be used when staff transport patients and the tent can protect the upper body of a bed-bound patient wearing a mask,allowing staff to perform several procedures.

“They represent a really simple solution to potentially helping reduce virus spread and increase the safety of healthcare workers, as well as patient safety,” says Ben Bassin.

When the researchers tested their devices with a healthy volunteer,they saw 97% to 99%fewer bacteria outside the devices than inside.They also tested the devices' ease of use and comfort with seven COVID-19 patients.The response from patients and staff was good, Bassin says.

But Reuben Strayer notes the tests did not prove that these devices work to protect medical staff in real-life situations. He says he wants to see independent effect, “to see if they perform as they are advertised.”

Eating a diet high in processed (加工的) food increases the risk of depression (沮丧抑郁), research suggests. What's more, people who ate plenty of vegetables, fruit and fish actually had a lower risk of depression, the University College London team found.

Data on diet among 3, 500 middle-aged civil servants were compared with their emotional state five years later, a British journal reported. They split the participants (参与者) into two types of diet--those who ate a diet largely based on whole food, which includes lots of fruit, vegetables and fish, and those who ate a mainly processed food diet, such as sweetened desserts, fried food, processed meat, refined grains and high fat dairy products. After accounting for factors such as gender, age, education, physical activity, smoking habits and chronic diseases, they found a significant difference in the future depression risk with the different diets.

Those who ate the most whole food had a 26% lower risk of future depression than those who ate the least whole food. By contrast, people with a diet high in processed food had a 58% higher risk of depression than those who ate a diet low in processed food.

Study author Dr Archana SinghManoux pointed out there was a chance the finding could be explained by a lifestyle factor they had not accounted for.

“There was a paper showing a Mediterranean diet was associated with a lower risk of depression, but the problem with that is if you live in Britain, the likelihood (可能性) of you eating a Mediterranean diet is not very high.”

Dr Andrew Mcculloch, chief executive of the Mental Health Foundation, said, "this study adds to an existing body of solid research that shows the strong links between what we eat and our mental health.”

He added people’s diets were becoming increasingly unhealthy. The UK population is consuming less nutritious, fresh produce and more saturated (含饱合脂肪酸的) fats and sugars.