Childhood fears are common, normal — Some behavior, such as nail biting, bed-wetting and fearfulness, may actually represent a temporary phase in normal development…. A most important finding [in a recent study] was that the fearful or anxious children, defined … as those with seven or more worries, did not seem to be in any particular psychological trouble.…Anxieties may be part of normal child development. — Science News, June 25, 1966

UPDATE
Actually, there is reason to worry about anxious children. Kids with anxiety disorders, depression or behavioral problems are especially likely to develop a range of difficulties as young adults, say researchers who conducted a long-term study published in 2015. The same goes for kids whose anxiety, mood or behavior issues cause daily problems but don’t qualify as psychiatric ailments. Problems that later dogged the study’s troubled youngsters, who grew up in rural North Carolina, included drug addiction, teenage parenthood, dropping out of high school and criminal arrests.

A mosquito’s spit can be worse than its bite alone. In some cases, the insect’s saliva makes the viral disease dengue fever more severe, a new study finds.

In mice, scientists found that mosquito spit weakened blood vessels, making them more permeable, or “leaky.” Easier exchange between the blood and tissues may help the virus spread faster — and increase the severity of disease — immunologist Michael Schmid and colleagues report online June 16 in PLOS Pathogens.

Dengue virus enters the bloodstreams of nearly 400 million people a year, through the sharp proboscises of tropical Aedes mosquitoes, which also deliver a spit-load of other molecules as they slurp a meal. There are four strains of dengue, which can cause bone and muscle aches, high fever and, in severe cases, death. Overcoming one type of dengue doesn’t protect the host from the other three strains. In fact, subsequent infections are often worse (SN: 6/15/16, p. 22).

Immune cells fight off the first dengue infection, and the body develops antibodies to that strain. But during a subsequent episode with a different variety of dengue, the antibodies from the first infection don’t kill the second — they amplify it. They pull new virus into healthy cells.

Scientists have studied this strange immune trap for three decades, “but what we didn’t know was that saliva could exacerbate it,” says Schmid, now at the University of Leuven in Belgium.
Investigating spit is important, says virologist Eva Harris of the University of California, Berkeley, a coauthor of the study. Molecules in mosquito saliva “can modify and modulate the infection process,” she says. Saliva’s role is well-studied in other viral diseases, like West Nile, but not for dengue.

Schmid’s team inoculated mice either with virus, saliva, or both virus and saliva, during primary and secondary dengue infections. In primary infections, the severity of the disease did not differ substantially between treatments. Symptoms were mild, at most. But in secondary infections, the combination of virus and saliva was lethal to more than half of the mouse population. Without the saliva, mortality was much lower.

To understand why, the researchers ran experiments to track viral spread through the circulatory system. In mouse ears, a molecule about the size of the dengue virus moved farther, and faster, when packaged with mosquito spit. And in the lab, human endothelial cells lining the inner walls of blood vessels sealed less tightly in the presence of Aedes saliva. The researchers also found that mice inoculated with virus alone could be rescued if the skin around the injection site was removed four hours later. The same procedure did not rescue mice dosed with virus and saliva.

These results should be interpreted with caution, says Duane Gubler, an infectious disease researcher at Duke University who was not involved in the study. Various environmental and genetic factors also play a role in the severity of the disease. “It’s not clear-cut,” he says.

Some bedbugs are better climbers than others, and the bloodsuckers’ climbing prowess has practical implications.

To detect and monitor bedbugs, people use an array of strategies from DIY setups to dogs. Pitfall traps, which rely on smooth inner walls to prevent escape, are highly effective for detecting and monitoring an infestation. The traps are sold around the world, but they have only been tested with common bedbugs (Cimex lectularius) — the most, well, common species in the United States.

As it turns out, tropical bedbugs (C. hemipterus) can easily scale the walls of pitfall traps, Chow-Yang Lee, an entomologist at Malaysia’s University of Science, and his colleagues found in lab tests. While 24 to 76 percent of tropical bedbug strains escaped traps, only 0 to 2 percent of common strains made it out. In measurements of vertical frictional force, tropical bedbugs also came out on top. Further investigation of the species’ feet revealed extra hairs on the tibial pads of tropical bugs. These may give their legs a better grip on trap walls, the researchers propose March 15 in the Journal of Economic Entomology.

Tropical bedbugs live in some regions of Africa, Australia, Japan, China and Taiwan — and have recently resurfaced in Florida.

Many babies born early spend extra time in the hospital, receiving the care of dedicated teams of doctors and nurses. For these babies, the hospital is their first home. And early experiences there, from lights to sounds to touches, may influence how babies develop.

Touches early in life in the NICU, both pleasant and not, may shape how a baby’s brain responds to gentle touches later, a new study suggests. The results, published online March 16 in Current Biology, draw attention to the importance of touch, both in type and number.

Young babies can’t see that well. But the sense of touch develops early, making it a prime way to get messages to fuzzy-eyed, pre-verbal babies. “We focused on touch because it really is some of the basis for communication between parents and child,” says study coauthor Nathalie Maitre, a neonatologist and neuroscientist at Nationwide Children’s Hospital in Columbus, Ohio.

Maitre and her colleagues studied how babies’ brains responded to a light puff of air on the palms of their hands — a “very gentle and very weak touch,” she says. They measured these responses by putting adorable, tiny electroencephalogram, or EEG, caps on the babies.

The researchers puffed babies’ hands shortly before they were sent home. Sixty-one of the babies were born early, from 24 to 36 weeks gestation. At the time of the puff experiment, they had already spent a median of 28 days in the hospital. Another group of 55 babies, born full-term, was tested in the three days after birth.

Full-term babies had a strong brain reaction to the hand puff. (This reaction was missing when researchers pointed the air nozzle away from the babies, a control that ruled out the effects of the puff’s sound.) Preterm babies had weaker brain reactions to the hand puff, the researchers found.

But the story doesn’t stop there. The researchers also looked at the number and type of touches — positive or negative — the preemies received while in the hospital.
Preemies who received a greater number of positive early touches, such as breastfeeding, skin-to-skin cuddles and massage, had stronger brain responses to the puffs than preemies who received fewer. More worryingly, preemies who had a greater number of negative touch experiences, including heel pricks, IV insertions, injections and tape removal, tended to have diminished brain responses to the puffs.

About a third of the premature babies in the study didn’t receive any positive touches that the researchers counted. Between birth and the time of the hand-puff experiment, the median number of positive touch experiences for the preemies in the study was 4. In contrast, the median number of painful procedures was 32.

The study turns up links, not cause. That means scientists can’t say whether the early touches, both positive and negative, are behind the differences in brain response. But it’s possible that early tactile experiences pattern the brain in important ways, Maitre says. If so, then the results have big implications.

Oftentimes, parents don’t have the luxury of snuggling their baby, particularly when parental leave is limited and babies are being treated far from home. Nurses, doctors and other medical professionals provide other forms of care. But anything parents, medical professionals or even volunteer cuddlers can do to shift the balance of positive and negative touches might encourage babies’ development, giving these smallest and newest of people the best start possible.

The heavy-duty material used to build bridges and sculpt skyscrapers could learn a few tricks from humble bones.

Steel’s weakness is its tendency to develop microscopic cracks that eventually make the material fracture. Repeated cycles of stress — daily rush hour traffic passing over a bridge, for example — nurture these cracks, which often aren’t apparent until the steel collapses. Bones, however, have a complex inner structure that helps them deal with stress. This structure differs depending on the scale, with tiny vertically aligned fibers building up into larger cylinders.
To mimic this variability, researchers fabricated steel with thin, alternating nanoscale layers of different crystal structures, some of which were just unstable enough to morph a bit under stress. That complicated microstructure prevented cracks from spreading in a straight line, slowing their take-over and preventing the material from collapsing, the scientists report in the March 10 Science. This experimental steel requires much more testing before it can be used in construction, says study coauthor C. Cem Tasan, a materials scientist at MIT. But the principles could be applied to other mixed-composition metals, too.

Hard-boiled eggs are a dish best served cold.

When quickly reheated in a microwave and then pierced, the picnic staple can explode with a loud bang in a shower of hot, rubbery shrapnel. But this blast is far more likely to make a hot mess than hurt your hearing, according to research presented December 6 at the Acoustical Society of America meeting in New Orleans.

That distinction isn’t as odd as it might sound. In a lawsuit, a man claimed to have suffered burns and hearing damage after a microwaved, hard-boiled egg exploded in his mouth at a restaurant. Researchers from Charles M. Salter Associates, Inc. in San Francisco called as expert witnesses couldn’t find scientific papers backing up the claim that an egg could burst with enough vigor to cause hearing loss — just a lot of YouTube videos documenting eggsplosions.
So the researchers microwaved peeled hard-boiled eggs in water on high power for three minutes.

The eggs were “uncooperative,” study coauthor Anthony Nash said in a news conference. Some exploded in the microwave, while others wouldn’t explode at all. But of nearly 100 eggs tested, 28 exploded outside of the microwave after being poked with a meat thermometer. From 30 centimeters away, the sound pressure from those explosions ranged from 86 to 133 decibels.

The median sound pressure level recorded, 108 decibels, is about the same as that at an average rock concert. Continuous exposure to that noise level could damage hair cells inside ears that respond to sound. The National Institute for Occupational Safety and Health sets recommended exposure limits for sound pressures above 85 decibels, says William Murphy, a researcher at NIOSH who wasn’t part of the study. But those limits are based on daily exposure over years, he says.
A burst egg’s boom, on the other hand, lasts just milliseconds — not long enough to do much harm. “The likelihood for hearing damage from a single exploding egg was very low,” Nash said.

The lawsuit was settled out of court before Nash and his colleagues conducted the second phase of the study – considering how sound hits your ears when it’s coming from inside your mouth. An in-mouth explosion might send slightly more sound pressure to the ears, Nash says, but still probably not enough to cause lasting damage as a one-time accident.

A peeled egg probably explodes when pockets of water trapped in the yolk become superheated — hotter than the boiling temperature of water without actually bubbling, Nash suggested. When disrupted, say by a fork or a tooth, the water pockets spontaneously boil, bursting through the squishy egg white and sending bits flying. (It’s the same phenomenon that can occasionally make microwaved coffee spurt out of the mug onto your clean work clothes.)

A bigger risk than the noise might be the heat. Nash and his colleagues measured the temperature of yolks in eggs that didn’t burst. Those temperatures were, on average, 12 degrees Celsius above the surrounding water bath, which was often close to boiling.

This year, gene therapy finally became a clinical reality. The U.S. Food and Drug Administration approved two personalized treatments that engineer a patient’s own immune system to hunt down and kill cancer cells. The treatments, the first gene therapies ever approved by the FDA, work in people with certain blood cancers, even patients whose cancers haven’t responded to other treatments.

Called CAR-T cell immunotherapy (for chimeric antigen receptor T cell), one is for kids and young adults with B cell acute lymphoblastic leukemia, or ALL, approved in August (SN Online: 8/30/17). The other is for adults with non-Hodgkin lymphoma, approved in October. Other CAR-T cell therapies are in testing, including a treatment for multiple myeloma.
“It’s a completely different way of treating cancer,” says pediatric oncologist Stephan Grupp, who directs the Cancer Immunotherapy Program at the Children’s Hospital of Philadelphia. Grupp spearheaded the clinical trials of the newly approved ALL therapy, called Kymriah.

Researchers are developing many different versions of CAR-T cell therapies, but the basic premise is the same: Doctors remove a patient’s T cells (immune system cells that attack invaders) from a blood sample and genetically modify them to produce artificial proteins on their surfaces. Those proteins, called chimeric antigen receptors, recognize the cancer cells in the patient’s body. After the modified T cells make many copies of themselves in the lab, they’re unleashed in the patient’s bloodstream to find and kill cancer cells.
CAR-T cell therapy is particularly exciting because it works well in people whose cancers haven’t responded to other available treatments, says Renier Brentjens, an oncologist at Memorial Sloan Kettering Cancer Center in New York City. Of the 63 kids and young adults treated in a clinical trial of Kymriah, 83 percent had their cancers go into remission within three months.
Now that these therapies have been clinically approved, there’s been an “explosion of interest” in the approach, says Dario Campano, an immunopathologist at the National University Cancer Institute in Singapore. Going forward, he expects to see even more rapid progress in the technology. Fifteen years ago, Campana helped develop the chimeric antigen receptor that’s used in Kymriah today. For now, the treatments are approved for use only when other treatments have failed, but someday CAR-T cell therapy could be the first treatment doctors try, he says.

One drawback is the price. Kymriah costs $475,000 for a onetime treatment, according to Novartis, which makes Kymriah. The non-Hodgkin lymphoma treatment made by Gilead Sciences, called Yescarta, is listed at $373,000. The total price tag for treatment could be higher when the costs of dealing with side effects and complications are factored in.

The approach is approved only for blood cancers. Using CAR-T cell therapy on solid tumors will require finding ways to get the T cells past additional cellular roadblocks, Grupp says.

Have you fallen behind on your reading this year? Or maybe you’ve plowed through your must-reads and are ready for more. Science News has got you covered. Here are the staff’s picks for some of the best science books of 2017. Find detailed reviews from previous issues in the links below or in our Editors pick: Favorite books of 2017.

Against the Grain
James C. Scott

Armed with the latest archaeological research, a political anthropologist argues that the rise of civilization came at a big cost. The initial switch from hunting and gathering to agricultural states brought poor diets, labor-intensive work, outbreaks of infectious diseases and other hardships (SN: 10/14/17, p. 28). Yale Univ., $26

The Great Quake
Henry Fountain

Historical records and interviews with survivors flesh out this tale of how a massive earthquake in Alaska in 1964 provided geologists with key evidence needed to verify the theory of plate tectonics (SN: 9/16/17, p. 32). Crown, $28

Eclipse
Frank Close

More than just a primer on the science of solar eclipses, this memoir chronicles a physicist’s lifetime fascination with the celestial phenomenon and introduces readers to the quirky world of eclipse chasers (SN: 5/13/17, p. 28). Oxford Univ., $21.95

Rise of the Necrofauna
Britt Wray

Resurrecting woolly mammoths, passenger pigeons and other extinct creatures isn’t just a technological problem, as this book explains. “De-extinction” is also rife with ethical dilemmas (SN: 10/28/17, p. 28). Greystone Books, $26.95

Big Chicken
Maryn McKenna

Antibiotics transformed chicken farming, to the detriment of the birds and of human health, a journalist contends. Widespread use of the drugs fueled the industrialization of poultry production and the rise of antibiotic-resistant bacteria (SN: 9/30/17, p. 30). National Geographic, $27

Inferior
Angela Saini

A science writer makes a persuasive case that centuries of biased thinking and flawed scientific research have reinforced sexist stereotypes about women (SN: 9/2/17, p. 27). Beacon Press, $25.95

Caesar’s Last Breath
Sam Kean

Through fun historical anecdotes and lesser-known backstories of scientific greats, this entertaining book profiles the chemical elements that make up the air we breathe and traces the history of Earth’s atmosphere (SN: 7/8/17 & 7/22/17, p. 38). Little, Brown and Co., $28

Cannibalism
Bill Schutt

The grisly practice of eating your own kind turns out to be widespread in the animal kingdom, a zoologist explains in this captivating look at cannibalism (SN: 2/18/17, p. 29). Algonquin Books, $26.95

The Lost City of the Monkey God
Douglas Preston

A journalist tags along on an archaeological expedition to search for the real-life remains of a mythological city in this rainforest adventure tale that morphs into a medical mystery (SN: 2/4/17, p. 28). Grand Central Publishing, $28

The Death and Life of the Great Lakes
Dan Egan

Invasive species, urbanization and other threats have wreaked havoc on the Great Lakes, but this book still finds some glimmers of hope in the scientists who are making headway in resuscitating the ecosystem (SN: 3/18/17, p. 30). W.W. Norton & Co., $27.95

How to Tame a Fox
Lee Alan Dugatkin and Lyudmila Trut

An experiment to replay animal domestication by selectively breeding wild silver foxes is lovingly retold, including by the researcher who has kept the project alive for nearly 60 years (SN: 5/13/17, p. 29). Univ. of Chicago, $26

Making Contact
Sarah Scoles

In the face of numerous obstacles, Jill Tarter still managed to spearhead the search for extraterrestrial intelligence for decades, as this biography recounts (SN: 8/5/17, p. 26). Pegasus Books, $27.95

A Crack in Creation
Jennifer A. Doudna and Samuel H. Sternberg

Two experts, including one of the pioneers of CRISPR/Cas9, discuss the science and ethics of gene editing. Houghton Mifflin Harcourt, $28

These book reviews contain links to Amazon.com. Science News is a participant in the Amazon Services LLC Associates Program. Please see our FAQ for more details.

Life expectancy in the United States has decreased for the second year in a row, the first back-to-back drops in more than 50 years, the U.S. Centers for Disease Control and Prevention reports.

In 2016, life expectancy at birth was 78.6 years for the U.S. population as a whole. That’s 0.1 year less than in 2015. For men, life expectancy decreased from 76.3 years in 2015 to 76.1 years in 2016, while in women it remained the same, at 81.1 years. The new data, from CDC’s National Center for Health Statistics, are published online December 21.
Heart disease was the leading cause of death for 2016, followed by cancer, unintentional injuries such as drug overdoses and car crashes, chronic lower respiratory diseases including asthma, and stroke. Rounding out the top 10 causes of death were Alzheimer’s disease, diabetes, influenza and pneumonia, kidney disease and suicide.

The overall drop in life expectancy is largely a result of an uptick in the age-adjusted death rates for unintentional injuries, Alzheimer’s disease and suicide, the report’s authors say.

Fracking wells should not go to 11. Instead, turning down the volume — that is, of water pumped underground to help retrieve oil and gas — may reduce the number of earthquakes related to hydraulic fracturing.

The amount of water pumped into fracking wells is the No. 1 factor related to earthquake occurrence at Fox Creek, a large oil and gas production site in central Canada, researchers report January 19 in Science. An injection of 10,000 cubic meters of fluid or more at a well appears to trigger a quake.
Fox Creek sits atop the Duvernay Formation, a sedimentary layer rich in oil and gas. Before December 2013, the area was earthquake-free. Since then, hundreds of earthquakes have shaken the region; most were below magnitude 4, but a magnitude 4.8 quake in 2016 temporarily shut down operations.

Previous investigations revealed that fracking well injections at the site were triggering earthquakes on an underlying fault system. But mysteries remained: For example, why didn’t the quakes didn’t start until almost three years after fracking activities began in 2010?

Ryan Schultz of the Alberta Geological Survey in Edmonton and his colleagues compared the timing and location of the earthquakes with fracking activity at 300 wells in the region.

An analysis of rates of injection, fluid pressure and fluid volume for the wells closest in proximity to the quakes revealed that, at this site, only volume was linked to the quakes. A previous study has linked the rate of wastewater disposal injections to seismic slip (SN: 7/11/15, p. 10).
As for the three-year delay, the authors say, fracking well injections tend to increase in volume over time as operations mature. So once the injection volumes reached that 10,000-cubic- meter threshold, the earthquakes began.