The Mother of All Apples Is Disappearing

By John Wenz | June 8, 2017 9:49 am
Malus-sieversii

You probably haven’t eaten this fruit before, but you may have one of its descendants in your house right now. (Credit: petrOlly/Flickr)

In the wilds of Kazakhstan, there’s an unassuming tree that bears an unassuming fruit. Like many plant species, development encroaches on its usual territory while climate change makes it harder for the tree to thrive and bear healthy yields of fruit.

You probably haven’t eaten this fruit before, but you may have one of its descendants in your house right now. After all, its children have more than 7,500 varieties in an assortment of colors and tastes and textures. Read More

CATEGORIZED UNDER: Environment, Top Posts
MORE ABOUT: plants

The 4 Big Discoveries Underpinning Our Knowledge of the Universe

By Scott Bembenek | June 7, 2017 11:53 am
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Astronomers using the Hubble Space Telescope assembled a comprehensive view of the evolving universe. (Credit: NASA/ESA)

For many, science is nothing more than that class you were required to take in school. However, whether you realize it or not, science is all around us, and it impacts every aspect of our lives. And, the stories behind key scientific discoveries, though not commonly known, are truly inspiring.

So, if you want a quick refresher on how the universe works, focus on these four fascinating discoveries and the history behind them: Read More

CATEGORIZED UNDER: Space & Physics, Top Posts
MORE ABOUT: cosmology, physics

The Dark Side of Laughter

laughter

(Credit: durantelallera/Shutterstock)

When you hear someone laugh behind you, you probably picture them on the phone or with a friend – smiling and experiencing a warm, fuzzy feeling inside. Chances are just the sound of the laughter could make you smile or even laugh along. But imagine that the person laughing is just walking around alone in the street, or sitting behind you at a funeral. Suddenly, it doesn’t seem so inviting.

The truth is that laughter isn’t always positive or healthy. According to science, it can be classified into different types, ranging from genuine and spontaneous to simulated (fake), stimulated (for example by tickling), induced (by drugs) or even pathological. But the actual neural basis of laughter is still not very well known – and what we do know about it largely comes from pathological clinical cases. Read More

CATEGORIZED UNDER: Health & Medicine, Top Posts

Malaria During Pregnancy Could Bolster Babies’ Immunity

By Kim Smuga-Otto | June 5, 2017 3:27 pm
tanzanian-mother

A mother and baby from the village of Pomerini, Tanzania. It’s estimated that the disease kills 60,000 to 80,000 people there annually. (Credit: Franco Valpato/Shutterstock)

You have a bit of your mother in you, literally.

When scientists performed biopsies of young adults’ organs, they’ve found maternal cells embedded in hearts, kidneys, and liver. This phenomenon, called microchimerism, is caused by a small number of cells passing through the placenta during pregnancy. The transfer goes both ways, and scientists think it’s like a meet-and-greet between mom and fetus, preventing their immune systems from treating each other’s cells as dangerous invaders. But that doesn’t explain why these cells stick around long after birth. Read More

CATEGORIZED UNDER: Health & Medicine, Top Posts

How the Chemicals in Sunscreen Protect Our Skin

Don’t skimp on the SPF. Sabphoto via Shutterstock.com

Don’t skimp on the SPF. (Credit: Sabphoto/Shutterstock)

Kerry Hanson, University of California, Riverside

Not so long ago, people like my Aunt Muriel thought of sunburn as a necessary evil on the way to a “good base tan.” She used to slather on the baby oil while using a large reflector to bake away. Aunt Muriel’s mantra when the inevitable burn and peel appeared: Beauty has its price. The Conversation

Was she ever right about that price – but it was a lot higher than any of us at the time recognized. What sun addicts didn’t know then was that we were setting our skin up for damage to its structural proteins and DNA. Hello, wrinkles, liver spots and cancers. No matter where your complexion falls on the Fitzpatrick Skin Type scale, ultraviolet radiation (UV) from the sun or tanning beds will damage your skin.

Today, recognition of the risks posed by UV rays has motivated scientists, myself included, to study what’s going on in our cells when they’re in the sun – and devise modern ways to ward off that damage.

UV light that affects our skin has a shorter wavelength than the parts of the electromagnetic spectrum we can see. Inductiveload, NASA, CC BY-SA

UV light that affects our skin has a shorter wavelength than the parts of the electromagnetic spectrum we can see.
(Credit: Inductiveload/NASA/CC BY-SA)

What Happens When Sun Hits Skin

Sunlight is composed of packets of energy called photons. The visible colors we can see by eye are relatively harmless to our skin; it’s the sun’s ultraviolet (UV) light photons that can cause skin damage. UV light can be broken down into two categories: UVA (in the wavelength range 320-400 nanometers) and UVB (in the wavelength range 280–320 nm).

(Credit: The Conversation, CC-BY-ND)

(Credit: The Conversation, CC-BY-ND)

Our skin contains molecules that are perfectly structured to absorb the energy of UVA and UVB photons. This puts the molecule into an energetically excited state. And as the saying goes, what goes up must come down. In order to release their acquired energy, these molecules undergo chemical reactions – and in the skin that means there are biological consequences.

Interestingly, some of these effects used to be considered helpful adaptations – though we now recognize them as forms of damage. Tanning is due to the production of extra melanin pigment induced by UVA rays. Exposure to the sun also turns on the skin’s natural antioxidant network, which deactivates highly destructive reactive oxygen species (ROS) and free radicals; if left unchecked, these can cause cellular damage and oxidative stress within the skin.

We also know that UVA light penetrates deeper into the skin than UVB, destroying a structural protein called collagen. As collagen degrades, our skin loses its elasticity and smoothness, leading to wrinkles. UVA is responsible for many of the visible signs of aging, while UVB light is considered the primary source of sunburn. Think “A” for aging and “B” for burning.

DNA itself can absorb both UVA and UVB rays, causing mutations which, if unrepaired, can lead to non-melanoma (basal cell carcinoma, squamous cell carcinoma) or melanoma skin cancers. Other skin molecules pass absorbed UV energy on to those highly reactive ROS and free radicals. The resulting oxidative stress can overload the skin’s built-in antioxidant network and cause cellular damage. ROS can react with DNA, forming mutations, and with collagen, leading to wrinkles. They can also interrupt cell signaling pathways and gene expression.

The end result of all of these photoreactions is photodamage that accumulates over the course of a lifetime from repeated exposure. And – this cannot be emphasized enough – this applies to all skin types, from Type I (like Nicole Kidman) to Type VI (like Jennifer Hudson). Regardless of how much melanin we have in our skin, we can develop UV-induced skin cancers and we will all eventually see the signs of photo-induced aging in the mirror.

Filtering Photons Before Damage Is Done

The good news, of course, is that the risk of skin cancer and the visible signs of aging can be minimized by preventing overexposure to UV radiation. When you can’t avoid the sun altogether, today’s sunscreens have got your back (and all the rest of your skin too).

Sunscreens employ UV filters: molecules specifically designed to help reduce the amount of UV rays that reach through the skin surface. A film of these molecules forms a protective barrier either absorbing (chemical filters) or reflecting (physical blockers) UV photons before they can be absorbed by our DNA and other reactive molecules deeper in the skin.

(Credit: The Conversation, CC-BY-ND)

(Credit: The Conversation, CC-BY-ND)

In the United States, the Food and Drug Administration regulates sunscreens as drugs. Because we were historically most concerned with protecting against sunburn, 14 molecules that block sunburn-inducing UVB rays are approved for use. That we have just two UVA-blocking molecules available in the United States – avobenzone, a chemical filter; and zinc oxide, a physical blocker – is a testament to our more recent understanding that UVA causes trouble, not just tans.

The FDA also has enacted strict labeling requirements – most obviously about SPF (sun protection factor). On labels since 1971, SPF represents the relative time it takes for an individual to get sunburned by UVB radiation. For example, if it takes 10 minutes typically to burn, then, if used correctly, an SPF 30 sunscreen should provide 30 times that – 300 minutes of protection before sunburn.

“Used correctly” is the key phrase. Research shows that it takes about one ounce, or basically a shot glass-sized amount of sunscreen, to cover the exposed areas of the average adult body, and a nickel-sized amount for the face and neck (more or less, depending on your body size). The majority of people apply between a quarter to a half of the recommended amounts, placing their skin at risk for sunburn and photodamage.

In addition, sunscreen efficacy decreases in the water or with sweating. To help consumers, FDA now requires sunscreens labeled “water-resistant” or “very water-resistant” to last up to 40 minutes or 80 minutes, respectively, in the water, and the American Academy of Dermatology and other medical professional groups recommend reapplication immediately after any water sports. The general rule of thumb is to reapply about every two hours and certainly after water sports or sweating

 In the U.S., the FDA regulates sunscreens available to consumers. Sheila Fitzgerald/Shutterstock.com

In the U.S., the FDA regulates sunscreens available to consumers. (Credit: Sheila Fitzgerald/Shutterstock)

What Makes A Good Sunscreen

To get high SPF values, multiple UVB UV filters are combined into a formulation based upon safety standards set by the FDA. However, the SPF doesn’t account for UVA protection. For a sunscreen to make a claim as having UVA and UVB protection and be labeled “Broad Spectrum,” it must pass FDA’s Broad Spectrum Test, where the sunscreen is hit with a large does of UVB and UVA light before its effectiveness is tested.

This pre-irradiation step was established in FDA’s 2012 sunscreen labeling rules and acknowledges something significant about UV-filters: some can be photolabile, meaning they can degrade under UV irradiation. The most famous example may be PABA. This UVB-absorbing molecule is rarely used in sunscreens today because it forms photoproducts that elicit an allergic reaction in some people.

But the Broad Spectrum Test really came into effect only once the UVA-absorbing molecule avobenzone came onto the market. Avobenzone can interact with octinoxate, a strong and widely used UVB absorber, in a way that makes avobenzone less effective against UVA photons. The UVB filter octocrylene, on the other hand, helps stabilize avobenzone so it lasts longer in its UVA-absorbing form. Additionally, you may notice on some sunscreen labels the molecule ethylhexyl methoxycrylene. It helps stabilize avobenzone even in the presence of octinoxate, and provides us with longer-lasting protection against UVA rays.

Next up in sunscreen innovation is the broadening of their mission. Because even the highest SPF sunscreens don’t block 100 percent of UV rays, the addition of antioxidants can supply a second line of protection when the skin’s natural antioxidant defenses are overloaded. Some antioxidant ingredients my colleagues and I have worked with include tocopheral acetate (Vitamin E), sodium ascorbyl phosophate (Vitamin C), and DESM. And sunscreen researchers are beginning to investigate if the absorption of other colors of light, like infrared, by skin molecules has a role to play in photodamage.

As research continues, one thing we know for certain is that protecting our DNA from UV damage, for people of every color, is synonymous with preventing skin cancers. The Skin Cancer Foundation, American Cancer Society and the American Academy of Dermatology all stress that research shows regular use of an SPF 15 or higher sunscreen prevents sunburn and reduces the risk of non-melanoma cancers by 40 percent and melanoma by 50 percent.

We can still enjoy being in the sun. Unlike my Aunt Muriel and us kids in the 1980s, we just need to use the resources available to us, from long sleeves to shade to sunscreens, in order to protect the molecules in our skin, especially our DNA, from UV damage.

 

This article was originally published on The Conversation. Read the original article.

CATEGORIZED UNDER: Health & Medicine, Top Posts
MORE ABOUT: personal health

Emerging Editing Technologies Obscure the Line Between Real and Fake

By Nathaniel Scharping | May 17, 2017 3:15 pm
Jennifer in Paradise (Credit: John Knoll)

Jennifer in Paradise (Credit: John Knoll)

The image is modest, belying the historic import of the moment. A woman on a white sand beach gazes at a distant island as waves lap at her feet — the scene is titled simply “Jennifer in Paradise.”

This picture, snapped by an Industrial Light and Magic employee named John Knoll while on vacation in 1987, would become the first image to be scanned and digitally altered. When Photoshop was introduced by Adobe Systems three years later, the visual world would never be the same. Today, prepackaged tools allow nearly anyone to make a sunset pop, trim five pounds or just put celebrity faces on animals. Read More

CATEGORIZED UNDER: Technology, Top Posts
MORE ABOUT: computers

Are We Ready for Robot Judges?

robot-judge

(Credit: Shutterstock)

Artificial intelligence is already helping determine your future – whether it’s your Netflix viewing preferences, your suitability for a mortgage or your compatibility with a prospective employer. But can we agree, at least for now, that having an AI determine your guilt or innocence in a court of law is a step too far?

Worryingly, it seems this may already be happening. When American Chief Justice John Roberts recently attended an event, he was asked whether he could forsee a day “when smart machines, driven with artificial intelligences, will assist with courtroom fact finding or, more controversially even, judicial decision making”. He responded: “It’s a day that’s here and it’s putting a significant strain on how the judiciary goes about doing things”. Read More

CATEGORIZED UNDER: Uncategorized

Can Math Can Save You From the Slow Line?

shutterstock_462351385

A sight we’ve all seen, but can we increase our odds of choosing the fastest line?

It seems obvious. You arrive at the checkouts and see one line is much longer than the other, so you join the shorter one. But, before long, the people in the bigger line zoom past you and you’ve barely moved toward the exit. The Conversation

When it comes to queuing, the intuitive choice is often not the fastest one. Why do lines feel like they slow down as soon as you join them? And is there a way to decide beforehand which line is really the best one to join? Mathematicians have been studying these questions for years. So can they help us spend less time waiting in line? Read More

CATEGORIZED UNDER: Space & Physics, Top Posts
MORE ABOUT: math

Is Technology Too Good for an Old-School Test of Einstein’s Relativity?

By Terena Bell | May 5, 2017 11:45 am
July 11, 2010 eclipse Image as viewed from Easter Island in the South Pacific. (Credits: Williams College Eclipse Expedition - Jay M. Pasachoff, Muzhou Lu, and Craig Malamut)

July 11, 2010 eclipse Image as viewed from Easter Island in the South Pacific. (Credits: Williams College Eclipse Expedition – Jay M. Pasachoff, Muzhou Lu, and Craig Malamut)

On Aug. 21, sky-gazers from around the world will converge in the United States as a total solar eclipse charts a path from Oregon to South Carolina. In between, on Casper Mountain in Wyoming, you’ll find Don Bruns with his telescope.

A retired physicist, Bruns is using the rare opportunity to test Albert Einstein’s general relativity like Sir Arthur Eddington, who was the first scientist to test the theory back in 1919. At that time, Newton’s law of universal gravity was still vogue, but Einstein shook the status quo by introducing his theory of general relativity, which fused concepts of time and three-dimensional space into a four-dimensional continuum called space-time. According to Einstein, gravity wasn’t a force; instead, it was a distortion in the fabric of space-time. Read More

CATEGORIZED UNDER: Space & Physics, Top Posts
MORE ABOUT: stargazing

How Tree Rings Solved a Musical Mystery

By Stephen E. Nash | May 3, 2017 10:15 am
tree-rings

Dendrochronologist Henri Grissino-Mayer and colleagues study the tree rings in the Karr-Koussevitzky double bass. Their analysis ultimately determined that the instrument was built much later than previously thought. (Credit: Henri Grissino-Mayer)

Modern science is full of surprising analytical techniques that can be used in a wide variety of remarkable circumstances.

My favorite technique is dendrochronology—the study of “tree time.” By assigning calendar-year dates to growth rings in trees, scientists can garner information relevant to an astonishing range of disciplines, including archaeology, climatology, the study of fire history, and many others. Read More

CATEGORIZED UNDER: Living World, Top Posts
MORE ABOUT: plants
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