© Takashi Tsuji, RIKEN
© Takashi Tsuji, RIKEN

Scientists Grow Hairy Skin in the Lab

© Takashi Tsuji, RIKEN
© Takashi Tsuji, RIKEN

Anybody can make skin cells—in fact, you’re doing it right now. But large, transplantable sheets of skin? That’s a bit harder. Still, it’s not impossible: Japanese scientists have successfully grown sophisticated artificial skin, including hair follicles and sweat glands. Their results were published last week in the journal Science Advances

These are heady days for lab-grown tissue. In the last decade, scientists have managed to create petri-dish tear ducts, kidneys, rat legs, muscle and bone, and even beef. All of this is good news, as transplantable organs and other body parts are in high demand, but some have been harder to cook up than others. Skin, for example. 

Your hide may look simple, but there’s actually a lot going on: there are three distinct layers (the epidermis, dermis, and hypodermis, which is composed of fat and connective tissue), sweat glands, and hair follicles. For skin to be skin, it’s got to be functional, lead author Takashi Tsuji said in a press statement. "Up until now, artificial skin development has been hampered by the fact that the skin lacked the important organs, such as hair follicles and exocrine glands, which allow the skin to play its important role in regulation.”

Tsuji and his colleagues decided to start at the very beginning, before skin cells are even skin cells. They used induced pluripotent stem cells (iPS), which are adult cells that have been reprogrammed with the stem-cell-like power to grow into anything.

The researchers used chemicals to activate a gene in the cells called Wnt10b, which is known for its role in skin growth. The iPS were cultured until they grew into little clumps called embryoid bodies (EBs), then transplanted into mice. Once inside the mice, the EBs continued to develop into skin tissue. To test the tissue’s medical potential, the researchers removed the new skin from the mice and transplanted it into other mice. They found that the artificial skin settled in and continued to develop normally as three-layered skin complete with glands and follicles. They also noticed that the new skin was able to connect with nearby nerves and muscles—an essential element in any transplanted tissue. 

Bioengineered skin with hair follicles. Image credit: © Takashi Tsuji, RIKEN

The researchers say their lab-grown skin is a step toward both important medical advances and a reduction in the use of lab animals in research (despite the study's reliance on mice subjects).

“With this new technique, we have successfully grown skin that replicates the function of normal tissue,” Tsuji said. “We are coming ever closer to the dream of being able to recreate actual organs in the lab for transplantation, and also believe that tissue grown through this method could be used as an alternative to animal testing of chemicals."

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Food
New Plant-Based Coating Can Keep Your Avocados Fresh for Twice as Long
Apeel
Apeel

Thanks to a food technology startup called Apeel Sciences, eating fresh avocados will soon be a lot easier. The Bill Gates–backed company has developed a coating designed to keep avocados fresh for up to twice as long as traditional fruit, Bloomberg reports, and these long-lasting avocados will soon be available at 100 grocery stores across the Midwestern U.S. Thirty or so of the grocery stores involved in the limited rollout of the Apeel avocado will be Costcos, so feel free to buy in bulk.

Getting an avocado to a U.S. grocery store is more complicated than it sounds; the majority of avocados sold in the U.S. come from California or Mexico, making it tricky to get fruit to the Midwest or New England at just the right moment in an avocado’s life cycle.

Apeel’s coating is made of plant material—lipids and glycerolipids derived from peels, seeds, and pulp—that acts as an extra layer of protective peel on the fruit, keeping water in and oxygen out, and thus reducing spoilage. (Oxidation is the reason that your sliced avocados and apples brown after they’ve been exposed to the air for a while.) The tasteless coating comes in a powder that fruit producers mix with water and then dip their fruit into.

A side-by-side comparison of a coated and uncoated avocado after 30 days, with the uncoated avocado looking spoiled and the coated one looking fresh
Apeel

According to Apeel, coating a piece of produce in this way can keep it fresh for two to three times longer than normal without any sort of refrigeration of preservatives. This not only allows consumers a few more days to make use of their produce before it goes bad, reducing food waste, but can allow producers to ship their goods to farther-away markets without refrigeration.

Avocados are the first of Apeel's fruits to make it to market, but there are plans to debut other Apeel-coated produce varieties in the future. The company has tested its technology on apples, artichokes, mangos, and several other fruits and vegetables.

[h/t Bloomberg]

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15 Facts About the Summer Solstice
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iStock

It's the longest day of the year in the Northern Hemisphere, so soak up some of those direct sunrays (safely, of course) and celebrate the start of summer with these solstice facts.

1. THIS YEAR IT'S JUNE 21.

June 21 date against a yellow background
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The summer solstice always occurs between June 20 and June 22, but because the calendar doesn't exactly reflect the Earth's rotation, the precise time shifts slightly each year. For 2018, the sun will reach its greatest height in the sky for the Northern Hemisphere on June 21 at 6:07 a.m. Eastern Time.

2. THE SUN WILL BE DIRECTLY OVERHEAD AT THE TROPIC OF CANCER.

A vintage mapped globe showing the Tropic of Cancer
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While the entire Northern Hemisphere will see its longest day of the year on the summer solstice, the sun is only directly overhead at the Tropic of Cancer (23 degrees 27 minutes north latitude).

3. THE NAME COMES FROM THE FACT THAT THE SUN APPEARS TO STAND STILL.

Stonehenge at sunrise.
CARL DE SOUZA, AFP/Getty Images

The term "solstice" is derived from the Latin words sol (sun) and sistere (to stand still), because the sun's relative position in the sky at noon does not appear to change much during the solstice and its surrounding days. The rest of the year, the Earth's tilt on its axis—roughly 23.5 degrees—causes the sun's path in the sky to rise and fall from one day to the next.

4. THE WORLD'S BIGGEST BONFIRE WAS PART OF A SOLSTICE CELEBRATION.

A large bonfire
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Celebrations have been held in conjunction with the solstice in cultures around the world for hundreds of years. Among these is Sankthans, or "Midsummer," which is celebrated on June 24 in Scandinavian countries. In 2016, the people of Ålesund, Norway, set a world record for the tallest bonfire with their 155.5-foot celebratory bonfire.

5. THE HOT WEATHER FOLLOWS THE SUN BY A FEW WEEKS.

Colorful picture of the sun hitting ocean waves.
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You may wonder why, if the solstice is the longest day of the year—and thus gets the most sunlight—the temperature usually doesn't reach its annual peak until a month or two later. It's because water, which makes up most of the Earth's surface, has a high specific heat, meaning it takes a while to both heat up and cool down. Because of this, the Earth's temperature takes about six weeks to catch up to the sun.

6. THOUSANDS OF PEOPLE GATHER AT STONEHENGE TO CELEBRATE.

Rollo Maughfling, the Archdruid of Glastonbury and Stonehenge, conducts a Solstice celebration service for revelers as they wait for the midsummer sunrise at Stonehenge on June 21, 2012, near Salisbury, England.
Rollo Maughfling, the Archdruid of Glastonbury and Stonehenge, conducts a Solstice celebration service for revelers as they wait for the midsummer sunrise at Stonehenge on June 21, 2012, near Salisbury, England.
Matt Cardy, Getty Images

People have long believed that Stonehenge was the site of ancient druid solstice celebrations because of the way the sun lines up with the stones on the winter and summer solstices. While there's no proven connection between Celtic solstice celebrations and Stonehenge, these days, thousands of modern pagans gather at the landmark to watch the sunrise on the solstice.

7. PAGANS CELEBRATE THE SOLSTICE WITH SYMBOLS OF FIRE AND WATER.

Arty image of fire and water colliding.
iStock

In Paganism and Wicca, Midsummer is celebrated with a festival known as Litha. In ancient Europe, the festival involved rolling giant wheels lit on fire into bodies of water to symbolize the balance between fire and water.

8. IN ANCIENT EGYPT, THE SOLSTICE HERALDED THE NEW YEAR.

Stars in the night sky.
iStock

In Ancient Egypt, the summer solstice preceded the appearance of the Sirius star, which the Egyptians believed was responsible for the annual flooding of the Nile that they relied upon for agriculture. Because of this, the Egyptian calendar was set so that the start of the year coincided with the appearance of Sirius, just after the solstice.

9. THE ANCIENT CHINESE HONORED THE YIN ON THE SOLSTICE.

Yin and yang symbol on textured sand.
iStock

In ancient China, the summer solstice was the yin to the winter solstice's yang—literally. Throughout the year, the Chinese believed, the powers of yin and yang waxed and waned in reverse proportion to each other. At the summer solstice, the influence of yang was at its height, but the celebration centered on the impending switch to yin. At the winter solstice, the opposite switch was honored.

10. IN ALASKA, THE SOLSTICE IS CELEBRATED WITH A MIDNIGHT BASEBALL GAME.

Silhouette of a baseball player.
iStock

Each year on the summer solstice, the Alaska Goldpanners of Fairbanks celebrate their status as the most northerly baseball team on the planet with a game that starts at 10:00 p.m. and stretches well into the following morning—without the need for artificial light—known as the Midnight Sun Game. The tradition originated in 1906 and was taken over by the Goldpanners in their first year of existence, 1960.

11. THE EARTH IS ACTUALLY AT ITS FARTHEST FROM THE SUN DURING THE SOLSTICE.

The Earth tilted on its axis.
iStock

You might think that because the solstice occurs in summer that it means the Earth is closest to the sun in its elliptical revolution. However, the Earth is actually closest to the sun when the Northern Hemisphere experiences winter and is farthest away during the summer solstice. The warmth of summer comes exclusively from the tilt of the Earth's axis, and not from how close it is to the sun at any given time. 

12. IRONICALLY, THE SOLSTICE MARKS A DARK TIME IN SCIENCE HISTORY.

Galileo working on a book.
Hulton Archive, Getty Images

Legend has it that it was on the summer solstice in 1633 that Galileo was forced to recant his declaration that the Earth revolves around the Sun; even with doing so, he still spent the rest of his life under house arrest.

13. AN ALTERNATIVE CALENDAR HAD AN EXTRA MONTH NAMED AFTER THE SOLSTICE.

Pages of a calendar
iStock

In 1902, a British railway system employee named Moses B. Cotsworth attempted to institute a new calendar system that would standardize the months into even four-week segments. To do so, he needed to add an extra month to the year. The additional month was inserted between June and July and named Sol because the summer solstice would always fall during this time. Despite Cotsworth's traveling campaign to promote his new calendar, it failed to catch on.

14. IN ANCIENT GREECE, THE SOLSTICE FESTIVAL MARKED A TIME OF SOCIAL EQUALITY.

Ancient Greek sculpture in stone.
iStock

The Greek festival of Kronia, which honored Cronus, the god of agriculture, coincided with the solstice. The festival was distinguished from other annual feasts and celebrations in that slaves and freemen participated in the festivities as equals.

15. ANCIENT ROME HONORED THE GODDESS VESTA ON THE SOLSTICE.

Roman statue of a vestal virgin
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In Rome, midsummer coincided with the festival of Vestalia, which honored Vesta, the Roman goddess who guarded virginity and was considered the patron of the domestic sphere. On the first day of this festival, married women were allowed to enter the temple of the Vestal virgins, from which they were barred the rest of the year.

A version of this list originally ran in 2015.

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