Discover的May 2018目录

Welcome to what our editors have been calling the “provocative medicine” issue. It’s our take on three areas that tend to be inherently interesting to readers. And that’s understandable, since they’re essential parts of being alive on this planet: pain, food and sex. It’s safe to say that most Americans have witnessed or known of a relative, friend or neighbor who has battled with addiction to opioids. For many, the incredible pull begins with painkillers prescribed after surgery or other medical care. We’ll always need painkillers, so how can researchers build a drug that doesn’t hijack the body with addiction? Contributing Editor Jonathon Keats finds out. Much of the food on grocery shelves, on the other hand, is plenty engineered, designed to hook us on the sugar and fat rush.…

EVER NOTICE HOW, when you take a bath, the water sloshes around when you move? The same thing happens when you scoot a cup of liquid around on a table. That sloshing movement happens on a large scale, too, in lakes and bays. It’s called a seiche (pronounced saysh), French for “to sway back and forth.” When the weather is calm, most of these bodies of water are pretty placid. But when winds pick up, when atmospheric pressure changes quickly or even when there’s enough seismic activity like an earthquake, it pushes water around, often away from the shore. In extreme cases, water retreats for so long that many people mistake it for a tide.…

Tools that allow scientists to map the human genome quickly and cheaply have made it much easier to hunt for a connection between genes and obesity. So far, scientists have identified more than 100 DNA differences that appear to be linked to obesity. Finding the correlation between genetic makeup and obesity is straightforward: Compare a number of genomes, and see where those of overweight people match up. But the job of figuring out what those genes do, and whether they may cause obesity, is much harder. Scientists are at the early stage, and they have investigated only a small portion of the potential genetic culprits. But “a lot of them seem to be acting in the brain,” says Mark Goodarzi, an endocrinologist at Cedars-Sinai Medical Center. They’re not regulating metabolism…

Just two weeks after his 24th birthday, Lowell Observatory assistant Clyde Tombaugh spotted a dim point of light moving slowly through a background packed with stationary stars. That tiny speck would come to be known as Pluto, a name suggested by an 11-year-old English schoolgirl. Find out how Venetia Burney named a planet, beginning on page 66, and how crowded our universe is, on page 60.…

1 The first thing to know about big cats: There’s no official definition of the term big cats. 2 In the 19th century, anatomist Richard Owen separated the family Felidae into “roarers” and “purrers.” Today, based on that distinction, some definitions consider cats “big” only if they roar — that’s lions, tigers, jaguars and leopards. 3 Owen thought that the different vocalizations stem from the anatomy of the hyoid, which supports the larynx and tongue. In purrers, this structure is rigid. In roarers, it’s more flexible. 4 Asia’s snow leopards defy that neat sorting, however. Despite having a flexible hyoid, the stealthy cats that locals call “ghosts of the mountain” don’t roar. 5 Researchers now think a pad of elastic tissue on the vocal folds, present only in roarers, explains…

Shouting in the Rain (“America Looks Up,” January/February 2018) I enjoyed reading the comments from people located in various areas of the country about their experiences with August’s solar eclipse, and wanted to give my take. My husband and I traveled to Columbia, South Carolina, which was on the tail end of the path of totality. The day was incredibly cloudy, so our viewing of the sun was sporadic. Right before totality, the clouds obscured the eclipse and it even started raining. We thought for sure we would miss our chance of a lifetime. However, at the exact second of totality, the clouds parted and there it was! We all started shouting, the rain not dampening our spirits at all! Marie Underdown Conroe, Texas A Solution to Marijuana Farm Pollution (“High…

IN HIS 40-PLUS YEARS AS A DEVELOPMENTAL BIOLOGIST at the University of Iowa, David Soll studied HIV, yeast infections and white blood cells. But after his wife died from a brain tumor eight years ago, Soll set his sights on cancer. Using a 3-D software system his lab previously designed to follow cell movement, Soll began tracking human tumor cells — including from breast, skin and brain cancers — photographing them from multiple angles every 10 minutes for up to three months. By studying the 3-D images chronologically, Soll became the first person to witness tumors forming in real time. It turns out that several cancers form tumors in a similar way, and he believes that one drug, yet to be discovered, could inhibit tumor formation in all cancers. As…

Pinpointing the Source of Opioid Prescriptions Researchers and health experts are drilling down into data to help find a solution to the country’s opioid epidemic. (For more on opioids, see page 42.) A recent review of data from 1996 to 2012 found prescriptions for the painkillers have been decreasing in emergency rooms, while doctor’s offices saw a significant uptick. This knowledge could assist policymakers on where to direct their efforts.…

A recent area of interest for obesity researchers is your gut and the bacteria that dwell there. Some research has found intriguing hints of a powerful relationship between this microbiome and your weight. In 2013, scientists transferred human gut bacteria from twins, one obese and one not, into mice. The mouse with the obese twin’s bacteria gained more weight than the other mouse. But people aren’t mice, says University of Michigan microbiologist Pat Schloss, author of a 2016 meta-analysis of multiple studies investigating the gut bacteria-obesity connection. Lab mice, for example, are bred specifically for sameness and are kept in highly controlled environments. Humans, by contrast, are nothing but chaos, and no two people are alike. In the 2016 paper, Schloss found that previous studies comparing the microbiomes of thin…

Bilsky started giving rodents drugs in the late 1980s. Early in his career, he worked with cocaine and MDMA. After repeatedly injecting rats with one of these drugs over a period of days, he used a test known as conditioned place preference to see whether they’d develop a liking for the drug: He observed whether the rats favored the part of the cage where they regularly got their fix, even when no drugs were offered. Not surprisingly, the rodents loitered there. But when Bilsky injected the rats with cocaine or MDMA and a chemical called CGS 10746B, the effect was completely different. CGS 10746B inhibits the release of dopamine in the brain. Without the exposure to dopamine, rats never developed a craving. These results make sense, according to Bilsky, when…

HOW MANY GALAXIES EXIST IN THE UNIVERSE? No one knows, but for a generation, astronomers have believed 100 billion was the answer. Now, we’ve discovered the number is likely much higher. It’s a perplexing puzzle to take on, because the universe is so large and has evolved so much over its 13.8 billion-year history. For many of us, it’s a problem that at first may seem as difficult as counting all the grains of sand on all the beaches on our planet. Like many others before and since, when I was growing up near the coast of Florida, I would often sit on the beach and admire the vast amount of sand before me. I would naturally ask myself, “How many grains of sand are there on this beach?” The…

Over the course of a decade, NASA’s Chandra X-ray Observatory spent several days trained on the Perseus galaxy cluster, about 240 million light-years away. Researchers knew they’d captured evidence of galaxies merging but didn’t understand how the process formed the pattern they were seeing. In June, a new study created this detailed image, which helped unravel the mystery. The merger was “like a gentle nudge,” says lead author Stephen Walker, and just big enough to create the hot hydrogen swirls seen here. “If it had been a much bigger crash,” Walker says, “it would have been immensely more complicated” — and possibly not as pretty.…

50 MILES About the height to which Martian dust storms can fling the planet’s water. Researchers examined over a decade’s worth of data and realized the storms ferried water vapor and ice away from the surface and up into the atmosphere. There, the sun’s ultraviolet rays broke down the vapor and ice into oxygen and hydrogen. The hydrogen then escaped the atmosphere, further dehydrating the Red Planet. 807,000 The number of people one study, based in Denmark, looked at to determine that there’s an association between developing dementia and lithium levels in drinking water. Citizens who ingested higher levels of lithium — about 0.015 milligram per liter — were less likely to develop dementia than those whose drinking water had lower levels of the metal. $3 MILLION Estimated worth of all the…

Researchers supporting what’s called the Insulin Hypothesis believe that sugar-rich beverages, as well as table sugar and refined starches, are driving dysfunction in our endocrine system, which controls metabolism and other crucial functions. These dietary carbohydrates, according to the Insulin Hypothesis, boost the body’s insulin secretion, which redirects fat to be stored in fat cells rather than used up as energy. The thinking is that high consumption of products such as SSBs leads to high levels of insulin, and that leads to high levels of fat being trapped in fat cells rather than being available as fuel for muscle and liver cells. The result is what some researchers call a state of “internal starvation” for those energy-deprived cells. The fuel is stored, so the body has fewer calories available to…