Dave Davies

The new strain of coronavirus that has killed hundreds of people in China and caused a travel lockdown of some 56 million people has been classified as a "zoonosis" because of the way it spreads from animals to humans.

Our ears are complicated, delicate instruments that largely evolved in far quieter times than the age we currently inhabit — an early world without rock concerts, loud restaurants, power tools and earbuds.

Writer David Owen describes our current age as a "deafening" one, and in his new book, Volume Control, he explains how the loud noises we live with are harming our ears.

More than 70,000 Americans died from drug overdoses last year, and a growing number of those deaths are attributed to the powerful synthetic opioid fentanyl. Journalist Ben Westhoff says the drug, while an important painkiller and anesthesia medicine in hospitals, is now killing more Americans annually as a street drug than any other in U.S. history.

Nearly 2,000 cities, towns and counties across America are currently participating in a massive multidistrict civil lawsuit against the opioid industry for damages related to the abuse of prescription pain medication. The defendants in the suit include drug manufacturers like Mallinckrodt, wholesale distributors McKesson and Cardinal Health, and pharmacy chains CVS and Walgreens.

Diver and photographer Jill Heinerth has explored unmapped, underwater caves deep in the earth, as well as the submerged crevices of an iceberg. She has seen hidden creatures and life forms that have never been exposed to the light of day.

"Since I was the smallest child, I always wanted to be an explorer — to have an opportunity to go someplace where nobody has ever been before," she says. "As an artist with my camera, it's an incredible opportunity to document these places and bring back images to share with others."

We tend to think of being asleep or awake as an either-or prospect: If you're not asleep, then you must be awake. But sleep disorder specialist and neurologist Guy Leschziner says it's not that simple.

"If one looks at the brain during sleep, we now know that actually sleep is not a static state," Leschziner says. "There are a number of different brain states that occur while we sleep."

As the cost of prescription medication soars, consumers are increasingly taking generic drugs: low-cost alternatives to brand-name medicines. Often health insurance plans require patients to switch to generics as a way of controlling costs. But journalist Katherine Eban warns that some of these medications might not be as safe, or effective, as we think.

As head of New York City's correctional health services, Dr. Homer Venters spent nine years overseeing the care of thousands of inmates in the jails on Rikers Island. Though he left Rikers in 2017, what he witnessed on the job has stayed with him.

"What's important to consider about jail settings is that they are incredibly dehumanizing, and they dehumanize the individuals who pass through them," Venters says. "There is not really a true respect for the rights of the detained."

Dr. Thomas Boyce, an emeritus professor of pediatrics and psychiatry at the University of California, San Francisco, has treated children who seem to be completely unflappable and unfazed by their surroundings — as well as those who are extremely sensitive to their environments. Over the years, he began to liken these two types of children to two very different flowers: dandelions and orchids.

When Joshua Mezrich was a medical student on the first day of surgical rotation, he was called into the operating room to witness a kidney transplant.

What he saw that day changed him.

After the donor kidney came out of ice and the clamps on it were released, he says, "it turned pink and literally, in front of my eyes, this urine just started squirting out onto the field."

By some accounts, nearly half of America's incarcerated population is mentally ill — and journalist Alisa Roth argues that most aren't getting the treatment they need.

Roth has visited jails in New York, Chicago, Los Angeles and Atlanta and a rural women's prison in Oklahoma to assess the condition of mentally ill prisoners. She says correctional officers are on the "front lines" of mental health treatment — despite the fact that they lack clinical training.

After Marine Sgt. Thomas ("TJ") Brennan was hit by the blast from a rocket-propelled grenade in Afghanistan in 2010, he suffered a traumatic brain injury that left him unable to recall much of his immediate past — including, at times, the name of his own daughter.

"When I got blown up, it erased a lot of my memories," Brennan says.