Chemistry of sunscreen

Me, hiding from the sun

It’s summer time!

It’s time for longer days, walks, sea, beach, hiking and nature.

But it is also time for sunscreens.

Have you ever ask yourself how do sunscreens protect our skin from the sun? Here, you will find the answer.

Sunscreens protect from the UV light emitted from the sun. UV light is a particular kind of light of the electromagnetic spectrum.

The electromagnetic spectrum

UV light (or rays) can be divided into three sub-types:

  • UV-A : 95% of the solar UV radiation is UV-A. This kind of light caused indirect DNA damage and contributes to skin cancer,
  • UV-B: 5% of the solar UV radiation is UV-B. This kind of light causes direct DNA damage and is the major contributor to skin cancer,
  • UV-C: it is filtered by the ozonosphere and doesn’t reach the Earth.

Sunscreen lotions contain molecules which are able to block UV-A rays only, or UV-B rays only, or both of them.

Organic UV-rays blockers

Menthyl anthranilate, for example, is a great UV-A blocker, homosalate is an excellent UV-B blocker and oxybenzone is able to block both UV-A and UV-B rays.

Protect our skin is of vital importance, but the use of sunscreen has also a negative effect on the coral reef.

Oxybenzone and other chemicals of sunscreens induce the bleaching of corals, which is the first signal of their death.

The concentration of oxybenzone is so elevated in the Hawaii (0.8 – 19.2 ug/L) that the government will ban sunscreens containing oxybenzone from 2021.

What is the solution to protect both our health and the coral reef?

Inorganic UV-rays blockers

Data show that sunscreens based on inorganic minerals, such as titanium oxide and zinc oxide, seem to be the safest for the coral reef, while protecting our skin from the UV light.

References:

Danovaro et al., “Suncreens cause coral bleaching by promoting viral infections”, (2008), https://doi.org/10.1289/ehp.10966

Lee Granger and Brown: “The chemistry and HPLC analysis of chemical sunscreen filters in sunscreens and cosmetics”, (2001), https://doi.org/10.1081/JLC-100107346

Raffa et al., “Sunscreen bans: Coral reefs and skin cancer”, (2018), https://doi.org/10.1111/jcpt.12778

Compoundchem: https://www.compoundchem.com/2014/06/05/sunscreenchemicals/

Cen: https://cen.acs.org/environment/pollution/Periodic-Graphics-Sunscreen-coral-reef/97/i28

Women in STEM: dr. Tahira

dr. Tahira and her amazing hair

My 31st guest is dr. Tahira, an Italian-Pakistani biochemist, who had courage to speak up for herself!

Hi @Dr_Tahira_Anwar! First of all would you like to tell us something about you?

My name is Tahira and I was born in Rome (Italy) from Pakistani parents. My parents moved to Rome in 1978 and both me and my brother were born there. I obtained my Master of Science in Biological Sciences from Sapienza University in Rome. While working as an intern for my Master thesis in a research laboratory, I took the decision to pursue a PhD abroad. I moved to Finland and joined the University of Helsinki where, after 10 long years, I obtained a PhD in Biochemistry.

When did you start your Twitter account? How did you get the idea?

I joined Twitter in March 2020. My PhD journey was very difficult and challenging. I struggled a lot with anxiety, burnouts, panic attacks and depressive episodes. Moreover, during my last year at the University of Helsinki, I went through some wrongdoings in campus due to a PI who used me for personal benefits, damaging my work and health. I got interested in mental health and academia wrongdoings and I wanted to connect with people working on these subjects. My goal is to be more active, share my experiences and create awareness on topics that are largely connected to life in academia.

Can you tell us something about how you balance work and private life? 

I learned the hard way that keeping a healthy work-life balance is very important. When I moved to Finland, I used to work every day, weekends included. I didn’t know anyone and immersing myself into work was the only way to escape isolation. After I burned out due to high level of stress and anxiety, I started taking care of myself and my well-being. No work on weekends (except if extremely necessary), regular exercise, healthy eating, time with friends and hobbies.

During your academic studies how many women were in course? Why in your opinion?

Most of the students during my bachelor´s and master´s degrees were women. During my PhD the difference was less striking though women still were outnumbering men. Several studies have shown that women face structural biases and barriers in their STEM careers such as gender disparity in getting hired, published, funded and reaching senior positions (“How the entire scientific community can confront gender bias in the workplace”, Kathleen E. Grogan, Nature Ecology & Evolution 2019). Unfortunately, there is not enough support for women and minorities inclusion in academic environments.

Have you ever felt harassed or being kept apart as a scholar because you are a woman?

During my PhD at the University of Helsinki, I went through some wrongdoings where a PI in my research programme promised me a job and used me for personal benefit, damaging my work and health. I have also been a victim of sexist and racist microaggressions during my PhD in Finland. But remember, always speak up girls!

How did you become passionate about science? 

As a kid, I always wanted to become a doctor but never had the courage to try the entry test (thank you, impostor syndrome and anxiety!). In high school, I found science a very fascinating subject and I was very much into science-related movies, documentaries and exhibitions. So, here I am today, with a master’s degree in biology and a PhD in Biochemistry.

dr. Tahira in the lab

Would you like to talk briefly about your job?

I worked as a PhD researcher at the University of Helsinki and I was studying Autophagy, a process by which cells eat themselves. Autophagy is important in many physiological processes and its defects are involved in many diseases such as cancer, infectious diseases, cardiomyopathies, neurodegenerative and muscular diseases. Autophagy is highly induced during starvation allowing cells to get back nutrients by degrading the cellular cargo. I performed in vitro studies to address autophagosome biogenesis and it´s regulation during starvation. During my PhD, I also did volunteer jobs in campus, taught in courses and supervised students.

Thank you so much for your time. Lastly, can you give any advice to girls interested in STEM?

First of all, thank you for giving me the opportunity to talk about me in your platform! Whatever your dream is, any career you want to pursue, any field you want to join, just go ahead towards your goal! There is not a thing you can´t do, there is not a job that is only for boys or girls. Try things, see what you like or not, move from one subject to another, from one career to another, science does allow that! Don´t get discouraged when things don´t work, don´t be ashamed to ask for help, look for resources and connect with people that can help you walk the wonderful STEM world.

Women in STEM: Neha

The physicist Neha

Update (25th July 2020). When I asked Neha to be part of my Women in STEM series, I didn’t pay enough attention to the pronouns listed both on Instagram and on Twitter.

When the interview was published, Luc Riesbeck approached me on Twitter and pointed out my mistake.

I had no excuse. I just didn’t read the pronouns description.

I want to publicly apologize for my mistake and for my behavior, if that caused suffering to Neha or any other non-binary person.

I need to do better.

We all need to do better.

I support #NonBinary everywhere and especially #NonBinaryinSTEM.

My 30th guest is Neha, an undergrad student of Mathematics and Physics universe passionate and science communicator.

Hi @nehathemartian! First of all would you like to tell us something about you?

I’m Neha and I am 20 years old. I am currently pursuing a Mathematics and Physics undergrad degree and am an avid scientific communicator. I love the universe and hope to study supermassive blackholes in the future.

When did you start your Twitter account? How did you get the idea?

I started my Twitter with the intention to connect to more academics because I didn’t have the representation that I needed in real life. I met amazing academics who were just like me and absolutely smashing it in their respective fields and then I knew i belonged.

Can you tell us something about how you balance work and private life? 

It’s all about how you devote your time.Being a student it’s hard but what’s important is that you always keep time aside for mental wellbeing. It doesn’t have to be something fancy, just drawing or listening to music can go a long way.

During your academic studies how many women were in course? Why in your opinion?

Only a few. I never really thought about it initially but seeing how it affected my stand as someone who wasn’t a man, I realized that this has to change and that women should be seen more in man dominated STEM fields.

Have you ever felt harassed or being kept apart as a scholar because you are a woman?

I have suffered through mansplaining, condescending messages and inequality through my years. And I hope to be a part of a change that wipes this out soon.

How did you become passionate about science? 

Look up at the stars. I was in awe of them and always wanted to understand them more. I read up every space book i could find and after that I discovered the works of Carl Sagan and then there was no looking back.

Would you like to talk briefly about your job?

I currently work in a material science lab to study potential materials that are sturdy and cheap to be used as semiconductors.

Thank you so much for your time. Lastly, can you give any advice to girls interested in STEM?

If you’re passionate about something, go for it. Don’t let anyone convince you that you aren’t cut out for science.

Science is for everyone, it doesn’t see any color, sex, gender and race.

Follow Neha on Instagram and on Twitter!

Neha
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