Showing posts with label science. Show all posts
Showing posts with label science. Show all posts
Tuesday, May 30, 2017
Is it Important to Get Three Free and Five Free Nail Polish The Science
Is it Important to Get Three Free and Five Free Nail Polish The Science
Ive had a few questions recently about two marketing buzzphrases in the nail polish business: "Three Free" and "Five Free".
"Three Free" nail polish is advertised as nail polish without Dibutyl Phthalate, Toluene, and Formaldehyde. "Five Free" nail polish is advertised as nail polish without Dibutyl Phthalate, Toluene, Formaldehyde, Formaldehyde Resin, and Camphor.
Theres a lot of scary shit written online about all of these chemicals, but without a lot of facts backing them up. So, what are these ingredients, and do you actually need to avoid them?
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| Image Source: https://www.flickr.com/photos/stevendepolo/ |
Dibutyl Phthalate
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| Dibutyl Phthalate Image Source: http://www.drugfuture.com/Pharmacopoeia/USP32/pub/data/images/v32270/cas-84-74-2.gif |
What Is It?
DBP and other phthalates are what is known as "plasticizers". These are additives that improve the plasticity of a substance.
Why Is It In Nail Polish?
What happens when your nail polish isnt flexible? It CHIPS. DBP in nail polish gives a longer wear-time.
Why Are People Freaked Out?
Phthalates are a controversial group as a whole, and DBP is probably one of the nastier versions. It affects testicular differentiation in frogs and fetal rats, and it has been hypothesized that it might have an effect on human fetal testicular development as well. There is also some evidence that it may disrupt thyroid receptor activity.
What Does the Science Say?
As with all things, the dose makes the poison. (As does the subject, since most of you are probably not male fetuses.) DBP exposure is considered to be acceptable at a rate of 0.01 mg per kg of body weight. I cant find any specific studies that look at he exposure you would face based on typical nail polish use, so its not clear whether adults will hit that threshold.
Personally, if there is one nail polish ingredient on this list that I would skip, this is the one. Luckily, for many of you, you probably dont have to do a lot to escape it. The European Union has banned the substance in cosmetics, and the only American producer, Eastman Chemical Company, stopped manufacturing DBP in 2011 (although it is still imported by a few companies). Im currently unable to find a single major nail polish brand that is still using the substance (although if you are aware of one, feel free to leave it in the comments below).
Its also worth noting that, given the research on fetal development, it is probably more important to avoid DBP if you are pregnant.
Toluene
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| Toluene Image Source: http://upload.wikimedia.org/wikipedia/commons/thumb/2/2e/Toluol.svg/230px-Toluol.svg.png |
What Is It?
Also referred to as phenylmethane, methylbenzene, or toluol, is what makes some nail polish smell like paint thinners. It is commonly used solvent.
Why Is It In Nail Polish?
Because toluene easily dissolves a wide variety of substances, using it as a nail polish solvent gives you a smooth, attractive application.
Why Are People Freaked Out?
Inhaling high doses of toluene results in headache, nausea, dizziness, drowsiness and confusion. It is also a minor skin irritant. Very high doses may harm the kidneys.
What Does the Science Say?
At the moment, concerns mostly center around inhalation of high doses. Solvent abuse ("huffing") or high levels of exposure in an industrial environment are the most significant concerns, rather than traditional nail polish use.
"Formaldehyde"
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| Formaldehyde Image Source: http://en.wikipedia.org/wiki/File:Formaldehyde-2D.svg |
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| Methanediol Image Source: http://en.wikipedia.org/wiki/File:Methanediol-2D.png |
What Is It?
Although nail polish companies commonly talk about "formaldehyde", formaldehyde is definitely not in your nail polish for one simple reason: formaldehyde is a gas. Formaldehyde definitely is toxic to all animals, causing death at high doses. It is also a known carcinogen, causing nasal cancer in rats.
If you are applying gas to your fingernails, we are not talking about the same products.
When we talk about "formaldehyde" in nail products, were presumably talking about methanediol (also known as methylene glycol). When you add water to formaldehyde, you go from an aldehyde that is a gas to a diol (meaning there are two OH groups) that is a liquid. It is a completely different substance.
Why Is It In Nail Polish?
Formaldehyde has never been in nail polish. Methanediol is a cross-linking agent that stiffens and hardens nails. Thus, it is commonly used in nail hardeners.
Why Are People Freaked Out?
People have incorrectly conflated formaldehyde and methanediol due to cosmetic mislabeling.
What Does the Science Say?
It is completely incorrect to conflate the dangers associated with formaldehyde with methanediol. Methanediol is considered by the FDA to be safe up to 5% concentration. Most manufacturers use levels between 0.5% and 2%, well within the safe limits. Even at higher doses, the primary concerns are skin irritation and allergies.
Formaldehyde Resin (Tosylamide/Toluenesulfonamide/TSF Resin)
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| Image source: http://theorganicsolution.files.wordpress.com/2012/09/p-toluenesulfonamide.jpg |
What Is It?
Despite the scary-sounding name, formaldehyde resin is also not the same thing as formaldehyde. Formaldehyde is used during the production of the substance, but is completely consumed by the reaction. Formaldehyde resin is a polymer, meaning the molecules stack together to make a durable film.
Why Is It In Nail Polish?
The resin helps the polish adhere to the nail, ensuring it wont peel or flake.
Why Are People Freaked Out?
Again, the word "formaldehyde" is scary.
What Does the Science Say?
Some research suggests that formaldehyde resin may be a concern for those who have significant levels of allergies or who are prone to contact dermatitis. Of course, all people should stick to painting their nails and not large chunks of their skin. Otherwise, despite the scary name, there is no evidence of harm.
Camphor
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| Camphor Image Source: http://upload.wikimedia.org/wikipedia/commons/0/02/Camphor_structure.png |
What Is It?
Camphor is a naturally-occurring chemical known for its strong scent. It has been used in European, Arabic, and Indian cuisine at various points in history. It gives a cooling feeling on the skin and is the active ingredient in Vicks VapoRub.
Why Is It In Nail Polish?
Camphor is another plasticizer, keeping your nails chip-free.
Why Are People Freaked Out?
Truly, I have no idea. Camphor is a poison when consumed in large doses. Adults typically see toxic effects after ingesting 2 g of pure camphor, with 4 g being the lethal dose.
What Does the Science Say?
Dont eat your nail polish.
What does it mean?
If you are buying standard nail polish brands in the United States or Europe and you are using them as intended (i.e. you are not eating or huffing them and youre putting them on your nail, rather than, say, your face), youre probably okay. If you have a tendency towards significant skin sensitivities (for example, if a nail polish has given you contact dermatitis in the past), you may want to be more careful around a few of these ingredients.
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Sunday, May 21, 2017
Is There Only One Right Answer A Challenge to the Teaching of Math and Science in Higher Ed
Is There Only One Right Answer A Challenge to the Teaching of Math and Science in Higher Ed
Many current promoters of MOOCs and other distance education models argue that higher education can be taught in a much more efficient way in fields like computer science, math, biology, and chemistry. According to high-tech educators, the main reason why these important disciplines can be streamlined is that there is only one right answer to questions and tests, and so a computer can easily grade these courses. On a most basic level, they claim that 2+2 will always equal 4, and thus, there is no need for creativity, critical thinking, or interactive discussions.
The problem with this logic is that it removes the STEM disciplines from any social, personal, or ethical context. In other words, students learn that math and science are impersonal, value-free fields founded on established, unchallengeable truths. While it is clear that students do need to learn basic formulas and concepts, all knowledge needs to be seen in its social and historical contexts. In fact, not only do we want students to think critically about the information they learn inside and outside of their classes, but we also need to train scientists and engineers to be innovative and creative. Moreover, with the increasing importance of issues like alternative energy, cloning, stem cell therapy, and climate change, science and math should be approached with ethical concerns front and center.
Purveyors of MOOCs like to say that online classes will not be any worse than the large lecture classes that dominate the undergraduate curriculum, and they have a point when they make this argument; however, we do not need a race to the bottom: what we need is to re-commit universities and colleges to spending resources on undergraduate instruction. Whether our goal is to compete in the global high-tech economy or train future citizens and responsible adults, higher education cannot be focused on simply transmitting and testing simplified facts and calculations. In fact, it is surprising that many of the most ardent promoters of MOOCs are themselves innovative computer scientists who think outside of the established box.
While China sends its students to American universities in order to build a creative class, it is ironic that the U.S. is seeking to dumb down its own curriculum. As I often tell my students, it is rare in life that you are confronted with one right answer or a simple multiple-choice test. Reality is far too complex for the reductive model of education that is often tied to MOOCs and a reductive vision of the STEM disciplines.
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Thursday, March 30, 2017
Islamic Golden Age of Science
Islamic Golden Age of Science
The series also features a story about Al-Khwarizmi: The father of algebra.
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