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Mosquito Magnets | Earth Wise

November 30, 2022 By EarthWise Leave a Comment

We’ve all probably had the experience of being in the great outdoors with other people and having some of them being nearly devoured by mosquitoes while others didn’t get bitten at all. It seemed like some people are mosquito magnets while others just aren’t the insects’ cup of tea, so to speak.

There have been various theories proposed over the years including such things as it being a question of blood type, or it having to do with how close one’s blood vessels are to their skin surface.

A new study by the Howard Hughes Medical Institute and the Rockefeller University has uncovered what appears to be the real explanation. According to the paper published in the journal Cell, certain body odors are the deciding factor. Every person has a unique scent profile associated with different chemicals present on their skin. The researchers found that people whose skin produces high levels of carboxylic acids are the most attractive to mosquitos.

The researchers collected scent samples from participants by having them wear silk stockings on their arms for six hours. The nylons were then cut into pieces and the pieces exposed to mosquitos. After several months of head-to-head battles between various nylon samples, the study clearly demonstrated that the samples from subjects with higher levels of carboxylic acids in the skin were far more attractive to mosquitos.

Humans produce the substance at much higher levels than other animals. There is little one can do about their own levels. Changing one’s diet or what soap they use doesn’t seem to make a difference.

Perhaps researchers can come up with some method of breaking down carboxylic acids in the skin in the future. Until such time, there are really people who are mosquito magnets.

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Some People Really Are Mosquito Magnets, and They’re Stuck That Way

Photo, posted September 4, 2014, courtesy of James Gathany / Centers for Disease Control via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Aluminum And Deodorants | Earth Wise

October 2, 2020 By EarthWise Leave a Comment

Aluminum is the third most common element in the earth’s crust. That element and its compounds are contained in numerous foods and products intended for consumers. Aluminum can occur naturally in certain foods and it can be a part of food additives. Apart from that, it is also possible for aluminum to transfer to food from packaging and tableware. We also can take in aluminum from cosmetic products like whitening toothpaste, lipsticks, particles in sunscreens, and in the form of aluminum chlorohydrate in antiperspirants.

The concern about aluminum intake is related to its effects on the nervous system, on the mental and motor development of children, and upon possible negative effects on the kidneys and bones. When aluminum is ingested via food, its toxicity is low and for healthy people, the kidneys do a good job of excreting it. However, people with chronic kidney disease may not be able to get rid of aluminum as readily and it can accumulate in the body.

Six years ago, a study looked at the amount of aluminum absorbed through the skin from the use of antiperspirants, but the data at that time was considered to be unreliable and a need for further research was identified.

Recently, the results of two new studies have been published by a German research institute that quantifies the absorption of aluminum salts through the skin. The results were that significantly less aluminum is absorbed through the skin than previously calculated and that a significant absorption of aluminum from antiperspirants is unlikely.

The total burden of aluminum from all sources can be high among some population groups, but it appears that use of aluminum-containing antiperspirants is not an important contribution to that burden.

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Aluminium in antiperspirants: Low contribution to the total intake of aluminium in humans

Photo courtesy of NutritionFacts.org.

Earth Wise is a production of WAMC Northeast Public Radio.

Sea Turtles Prospering During The Shutdown | Earth Wise

May 14, 2020 By EarthWise Leave a Comment

Our stories often discuss how human activities change the natural environment. With most of us confined to our homes, the lack of human activities is having profound effects on the environment. We are talking about some of these this week.

Seven different species of sea turtles are found in the world’s oceans and play important roles in marine ecosystems. Over time, human activities have tipped the scales against the survival of these animals. They have been hunted for their eggs, meat, skin, and shells and face habitat destruction and accidental capture in fishing gear. Their nesting grounds in beaches are constantly disturbed and endangered by human activity.

With the beaches in Florida closed in the effort to stop the spread of coronavirus, there is less plastic waste, fewer people and vehicles, and fewer artificial lights on the beach that disorient emerging turtle hatchlings. Because of all of these factors, sea turtles have been building their nests without disruptions.

In April, it was nesting season for leatherback turtles, the largest of all sea turtles. In May, loggerhead turtles arrive in Florida. Later in the summer, green turtles will arrive.

It takes about 60 days for sea turtle eggs to incubate and to hatch. During that period, lots of things can happen to a nest on an active beach – it can get trampled, people can dig it up, and artificial light can confuse the hatchlings as they try to find their way to the water. With the current shutdown, it should be a productive nesting season for sea turtles.

On the other hand, when beaches reopen, there may well be a major influx of people flocking to the beach because they have been stuck indoors for an extended period of time.

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Sea turtles are thriving as coronavirus lockdown empties Florida beaches

Photo, posted August 9, 2016, courtesy of Florida Fish and Wildlife via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

A Squid Skin Blanket

June 25, 2019 By EarthWise Leave a Comment

Ultra-lightweight space blankets have been around for a long time. Marathon runners wrap themselves in them to avoid losing body heat after a race. They are very effective, but the amount of heat that they trap is fixed. There is no way to regulate how much heat is trapped or released using a space blanket.

Researchers at the University of California, Irvine have developed a next-generation, adaptive space blanket that allows users to control their temperature. The inspiration for the design was the skins of various species of squids, octopi and cuttlefish. The ability of these aquatic creatures to camouflage themselves by rapidly changing color is due, in part, to skin cells called chromatophores that can instantly change from tiny points to flattened disks.

The Irvine researchers have developed a material that contains a layer of tiny metal islands that border each other. In the relaxed state, the islands are bunched together, and the material reflects and traps heat, much like a conventional Mylar space blanket. But when the material is stretched, the islands spread apart, which allows infrared radiation to go through and heat to escape.

The researchers envision many other applications for the novel material, including adaptable insulation for buildings and tents that can be adapted to different weather conditions. There is even the possibility of clothing that can be adjusted to suit the comfort of each person.

The new material is lightweight, easy and inexpensive to manufacture, and is durable. It can be stretched and returned to its original state thousands of times. Some day we might all be wrapping ourselves in imitation squid skins.

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Squid skin inspires creation of next-generation space blanket

Photo, posted May 29, 2005, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Natural Mosquito Repellents

June 20, 2017 By EarthWise

With summer comes mosquitoes and our desire to keep them away from us. The most common repellents are based on the chemical DEET, which unfortunately has been found to have several health and safety problems. Up to 15% of DEET is absorbed through the skin directly into the bloodstream. Diethyl-meta-toluamide, the chemical name for DEET, has been shown to have a variety of toxic effects. Fortunately, it turns out that there are some natural alternatives which may be as effective as DEET, or possibly even more effective than DEET in keeping mosquitoes away from us.

DNA Analysis of River Water

April 17, 2017 By EarthWise

DNA analysis has become commonplace and inexpensive. Millions of people have their DNA tested to learn about their origins and family connections. And the technology has spread to biological research in the form of Environmental DNA or eDNA, which is such a powerful tool that it is transforming the field of wildlife biology.