54th volume - Second edition

Study Trip Cologne & MĂźnster On Stage Visiting our Northern neighbours Science One town, four elements

Ice Cold Chemistry Chimica Acta Lugduni 54th volume - Second edition 2019-2020

Ice Cold Chemistry Praesidiaal 3 Exhilarate 4 Science 6 Study Trip 8 CDL Integraal 12 Gadget 14 Photo page 16 On Stage 18 BB 22 In de toren 26 Lijn 43 28 Education 31

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The Chimica Acta Lugduni is the magazine for the Chemisch Dispuut Leiden (CDL). Chemisch Dispuut Leiden is the study association of the bachelor Molecular Science & Technology and the master Chemistry.

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Editorial Board Christine Visser (Editor in chief)

Maartje Zweers

Lise van den Bos (Editor in chief)

Pepijn Lammers

Chemee Parree

Renate de Vreede

Joeri Schoenmakers

Sterre de Lange

Lies Levering

Jitske Hubert (QQ)

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Dear reader, This wonderful second edition of the Chimica Acta Lugduni of the year is all about Ice Cold Chemistry, which is applicable as this edition of our magazine covers most of what happened during the winter months. Also, quite some CDL members have traveled northwards for their studies, and I cannot wait to read their stories!

Even though the cold may sometimes slow things down, since the first edition of this year’s Chimica lots of magnificent activities have been organized. The AkCie has outdone themselves by organizing an amazing Christmas dinner with a spectacular afterparty in the Hut! The day after was spent in the Science Club with lots of snacks and movies and was concluded by the destination reveal of the foreign excursion by the MexCie. The trip will go to Geneva and Milan during the first week of the summer break! This is not the only trip of the year, the neighbouring countries trip (BRC) has just returned from Germany, and I hear it has been a huge success! Furthermore, the M.A.T.C.H. has ended with a great win by team The Enthalpiraten. Congratulations!

Besides keeping busy with all these activities, ‘Exhilarate’ has also worked hard on solidifying some plans from our policy plan. For instance, some of you may be reading this on a screen instead of the classical paper print. A decision that was made in the spirit of sustainability. Furthermore, there have been tours of almost all the research groups of the Leiden Institute of Chemistry (LIC). Hopefully, more students now know what types of research is conducted in our institute and are better able to make an informed decision about their further education and research projects.

I also want to make use of this platform and look ahead to some of the upcoming activities, as there are a couple of great ones coming up! For example the senior student weekend (OJW), the dies celebration weeks and the ONCS sports tournament. Besides these recreational highlights, a lot of educational or career activities are being organized as well, such as the Ladies Career Night, the CDLIFE career night and multiple lunch lectures. If you do not want to miss any of this, check the activities overview on the website regularly!

In conclusion, on behalve of the entire board, I want to wish everybody lots of success with all the tests and projects of this coming semester. Until then, enjoy this second edition of the Chimica!

Lara van der Poll h.t. praeses of the Chemisch Dispuut Leiden

Dear reader, I am very proud and happy to present you the first edition of the Chimica of 2020! This means that we are already in the second semester of this academic year and that winter is almost over.

Well, at least the astronomical winter, because it has not been truly cold the past few months.

Maybe that is why some some MST- and Chemistry students visited our nothern university neighbours for an internship or minor. Of course they enyojed their trip (read about this on page 18-20), but back in Leiden, they recieved a warm welcome home.

In the meantime, a lot of activities have been organized for those who stayed here. The M.A.T.C.H. has ended, some students went on an amazing studytrip to Germany and a lot of career events have been organised.

The second semester also brings us closer to the Dies of CDL! We are priveledged to present more information about this spectacular event. You can read about this on page 21.

Christine Visser Editor in chief Chimica Acta Lugduni

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Halfway point

The best is yet to come

On Monday, February 24th, it was time for the third general assembly of this academic year, and with that, the halfway point of the 87th board had been reached. Therefore, the first part of the evening was mostly about looking back on the past few months, the activities and the fun times everybody has had together. It was also a moment for everybody to review the first part of the year, and to learn from the mistakes that have been made. But it was also an evening of looking forward, to all the things that are yet to come.

However, first it was time for three committees to present their budgets. The Freshmen Introduction Weekend committee of 2019 started of with their final settlement for the weekend that took place last summer. And after some questions were answered, everybody agreed with the numbers that were presented. Directly following on 2019, the First Year Weekend committee 2020 presented their budget for coming summer. Also, the Foreign Excursion committee had to present their estimated budget for the trip to Geneva and Milan in July.

Following the committees, it was finally time for Sjoerd to climb the ladder and present the revised budget for the CDL. In the past few months, some money was saved on things like printing costs. That meant that some of the committees got assigned more money to organize activities. Furthermore, money has been set aside for a fifth computer for when we move to the new Gorlaeus Building.

An extra item on the agenda for this assembly was the nomination of a new honorary member of the CDL. Previously, the association counted five of these members: Theo van Heijningen, Jan Mulder, Trudie Brouwer, Jan Reedijk and Rob van Waarde.

The last of these was asked to be an honorary member in 2013 and therefore it was about time to nominate a new member. The board chose to nominate Prof. dr. E. Bouwman, someone who has showed many times that she has a heart for the students, education and the CDL. And after a voting, all attendees agreed to make Lies Bouwman our sixth honorary member.

As in every general assembly, the committees had the opportunity to give a short presentation and while most of the committees were installed in the previous general assembly, there were still a few people who were installed this evening.

The last thing that remained before the assembly was finished, was to look forward to all the activities ahead. And with our 94th Dies Natalis and the ONCS, we can in all probability say: ‘The best is yet to come’.

Jitske Hubert

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One town, four elements Since four of our own CDL students visited Scandinavia in the past couple of months, this edition’s “Science” will be about a special place in the Northern European region: the village Ytterby on the Swedish island of Resarö. Why is this place so extraordinary? And why is it particularly interesting for chemistry students?

Resarö is an island in the Stockholm archipelago, a cluster of islands roughly 60 kilometres to the east of Stockholm. On this island you will find a small village named Ytterby, which translates to “outer village”. Ytterby is famous for its rich mine.

In 1787 an army lieutenant called Carl Arrhenius discovered a black rock in the mine of Ytterby that was heavier than regular rocks. In 1792 a Finnish chemistry professor at the Royal Academy of Turku named Johan Gadolin received a sample of the black rocks to run some tests on it.[1][2] Back in those days they did not know much about chemistry at all, the periodic table did not exist yet. In fact, Lavosier had just published Figure 1 Carl Arrhenius the basis of “Traité élémentaire de chimie”, which is known to be the first chemical textbook ever made.[3] Gadolin experimented on the black rocks and identified the mineral contained a new unknown rare-earth element. An element which later became known as yttrium.[2]

Yttrium (Y) Yttrium is the first of seventeen rare earth elements that was discovered. A rare earth element is hard to find on its own, they are usually found as minerals mixed with other elements.

Unlike the name suggests, rare earth elements are actually not very rare. The mine of Ytterby alone used to contain loads of the mineral gadolinite which contains yttrium and the element is also found in the earth’s crust. Isolating pure yttrium from this mineral is not that easy,[4] which is why this

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only happened more than 35 years later by a chemist named Friedrich Wöhler. He passed chlorine gas over the mineral containing yttrium to form yttrium chloride, which was reduced to yttrium using potassium.[2] Yttrium is commonly used in white LEDs and phosphors and it is also found in other devices such as lasers used in medical and industrial applications. Yttrium complexes can be used as a Lewis acid to catalyze reactions. The most important use of yttrium is its role in high temperature superconductors as yttrium barium copper oxide. Superconductors are strong magnets used in MRIs and many other scientific instruments.[2][5][6]

Erbium (Er) Erbium and terbium were discovered in 1843 by another Swedish man named Carl. Carl Gustaf Mosander was experimenting on a sample of yttria (yttrium oxide Y2O3) and discovered the sample was actually a mixture of yttria, erbia, and terbia.

Erbium oxide is rose-colored and is sometimes used as a colorant for different materials. Erbium is used together with yttrium in lasers. These Figure 2 Carl lasers are useful because the light Gustaf Mosander does not travel through the human tissue, and therefore they are used in medical applications.

For example by dermatologists[7] and dentists,[8] when only the surface of the skin or a tooth needs to be treated.[5]

Terbium (Tb)

Mosander also discovered terbia, the oxide of terbium. Pure terbium wasn’t isolated until the advent of ion exchange techniques. Terbium is just like yttrium commonly used in white LEDs and phosphors, terbium oxide is used in green phosphors for fluorescent lamps and television tubes.[5][10] Terbium can also be used in a complex as a small and strong “single-molecule’’ magnet, which is interesting for many technological applications.[11]

Ytterbium (Yb) To finish the Ytterby elements-quartet, we have ytterbium.

This element was discovered by the Swiss chemist Jean Charles Galissard de Marignac in 1878, which is a lot later than the other three elements. Marignac was examining samples of gadolinite when he discovered the mineral contained yet another unknown component. Just like erbium, ytterbium is used in yttrium lasers, but the most important use of ytterbium is in high-stability atomic clocks[9]. Atomic clocks use vibrating atoms to track the time.

The ytterbium atomic clock is even more accurate than the commonly used caesium atomic clock, which Figure 3 Jean Charles means it can do even more precise [5] Galissard de Marignac measurements.

“Atomic clocks use vibrating atoms to track the time. The ytterbium atomic clock is even more accurate than the commonly used caesium atomic clock.”

So, the reason this town is so special is because it has these four rare earth elements named after it. Much later it was discovered that the gadolinite mineral from the mine of Ytterby contained even more elements, like scandium (named after Scandinavia), gadolinium (named after Johan Gadolin) and more.[5] Which makes the mine of Ytterby the riches source of elemental discoveries in the world. Of course, all these Figure 4 Johan Gadolin Ytterby elements have even more applications than described in this article and the research on the elements is still going on.

Chances are you’ve never heard of this city before reading this Science and yet it holds a scientific record for being the source of so many elements. So, if you’re ever on a trip to Sweden and have some spare time, a visit to Resarö and the mine of Ytterby is definitely worth your while!

References [1] Knutson Udd, L.; Leek, T. (2012). Ytterby gruva. Eskilstuna: Fortifikationsverket.

[2] Dinér, P. (2016). Yttrium from Ytterby. Nature Chem 8, 192. https://doi.org/10.1038/nchem.2442 [3] Lavoisier, A. L. (1789). Traité élémentaire de chimie (t. 1 (1789)). Paris: Chez Cuchet.

[4] Connelly, N. G; Damhus, T. (2005). Nomenclature of Inorganic Chemistry: IUPAC Recommendations 2005.

Cambridge: RSC Publishing.

[5] The University of Melbourne blog: Scientific Scribbles. The Ytterby Elements. (2016, October 15). Retrieved from https:// blogs.unimelb.edu.au/sciencecommunication/2016/10/15/ the-ytterby-elements/.

[6] Cotton, Simon A. (2006). “Scandium, Yttrium & the Lanthanides: Inorganic & Coordination Chemistry”.

Encyclopedia of Inorganic Chemistry.

[7] Teikemeier, G; Goldberg, D.J. (1997). Skin Resurfacing with the Erbium: YAG Laser. Dermatologic Surgery, 23: 685-687. https://doi.org/10.1111/j.1524-4725.1997.tb00389.x [8] Glenn, A. S. (2004). Erbium lasers in dentistry. Dental Clinics, Volume 48, Issue 4, 1017 – 1059. https://doi. org/10.1016/j.cden.2004.06.001 [9] Hinkley, N.; Sherman, J. A.; Phillips, N. B.; Schioppo, M., Lemke, N. D.; Beloy, K.; Pizzocaro, M.; Oates, C. W.; Ludlow, A. D. (2013) An Atomic Clock with 10–18 Instability. Science, 341, 6151, 1215-1218, 10.1126/science.1240420.

[10] Hammond, C. R. (2005). “The Elements”. In Lide, D. R. (ed.). CRC Handbook of Chemistry and Physics (86th ed.).

Boca Raton (FL): CRC Press. ISBN 978-0-8493-0486-6.

[11] Zhang, P.; Zhang, L.; Tang, J. (2015) Lanthanide single molecule magnets: progress and perspective, Dalton Trans., 2015, 44, 3923, https://doi.org/10.1039/C4DT03329A

Lise van den Bos

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Cologne & Münster This year, members of CDL left for Germany on the third of February. Every year, the BRC (the neighbouring countries trip committee) chooses several destinations in either Germany or Belgium and students can sign up for the trip. In Germany (first in Cologne then Münster) we visited several companies and institutions. During this trip there was a lot of attention for chemical innovation. The BRC is an unique opportunity to discover which companies are important for the chemical industry in Germany. We left for Germany with 23 students, the names of whom you can find below.

On the next page you can read how Maxime Brohet, treasurer of the BRC, experienced this trip.

This year’s BRC participants...

Pim van Duren Maxime brohet Chris Klomp Thomas van Roeden Cesar van Nispen Renate de Vreede Jesse Orta Martine van Rijn Sjoerd Rieken Erik Goudart Niels Jansen

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Steef van Rijen Lauren van Nijll Bjorn van der Vuurst Niels van ‘t Riet Rick Monsma Sharief Mokhtari Fleur van Loo Jitske Hubert Jasmijn van Arnhem Déan van Dijk Gabriel Stead

Hey Maxime, what was your experience being part of the BRC committee?

This year, I had the honour of being the treasurer of the BRC and there was something special about the trip this year!

For the first time in many years, we chose Germany as our destination instead of Belgium. Early in the process, we discussed going to Germany and decided to go to Cologne and Münster. We made this decision because there are some great universities and companies to visit in these cities.

Besides these professional benefits, Cologne and Münster are also very beautiful cities, so lots of potential for sightseeing.

going to the museum of beer. Upon arrival this turned out to be more of a bar than a museum, but we had a great time nonetheless. That night was spend enjoying some of the finer German beers and playing cards.

So... How did the trip go?

On Monday February third, me and my roommates woke up at around 5:30h, so we could be at Leiden Central Station at 7:00h in the morning. When we arrived, the first thing we did was congratulate Chris! He and I share a birthday so we were flooded with congratulations and well-wishes. This was fun eventhough we were quite sleep-deprived. Everyone got there in time and we took the train to Cologne.

Wednesday, we left early in the morning to visit the Max Planck Institute for plant breeding research just outside the city. In this environment everyone found their inner peace.

We got to look around the grounds and visit the greenhouses.

That afternoon we had a lecture about phloem cells in plants.

An interesting topic almost no-one knew anything about before the lecture.

That afternoon we took the train to Münster, which gave everyone a moment to catch up on some sleep! The sun was setting, our train compartment looked like the one from Harry Potter and we put some relaxing music on - everyone was feeling the good BRC energy. That night, me and some friends ate at a Nepalese restaurant at walking distance from the hostel we were staying at.

When we arrived we checked in our bags at the hostel and got straight back in the bus to go to our first company; Dralon.

Dralon is known for making polyacrylic fibers, and we got to see this up close. They gave us a fascinating tour through the factory and everyone was amazed to see these huge processes. There was a slight hiccup when one of our first year students had an allergic reaction to one of the sandwiches provided. He was rushed to the hospital and thankfully was okay again by the evening. He was able to enjoy the rest of the trip with us, something we were collectively grateful for.

That night, the group split up to eat either burgers or döner, a balanced meal for sure. The committee stayed up late taking care of some things (and of course playing cards).

On Tuesday, we spent the morning in the lovely chocolate museum. That afternoon, we let all the students roam free in Cologne. I think everyone visited the dom and had something to eat at a German bakery, two activities you can’t miss when in Cologne. That night we expanded our cultural horizon by

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The committee of 2020 Thursday we planned something really exciting; a visit to the Faculty of Chemistry of the University of Münster.

Upon arrival we enjoyed a Dutch presentation about all the activities occuring in the Centre for Soft Nanoscience. Some of the highlights of this presentation included an explanation about photochemistry and photosensitive molecules.

After an intriguing tour through the laboratories, another presentation was scheduled. This time one of the professors at the institute gave us an impromptu presentation about his research and everything there is to do in Münster.

That night was our last night in Germany, and we went out with a bang. The committee organised a Disney pubcrawl!

This resulted in way too many overdressed students crowding small bars - something we all thoroughly enjoyed. We got a lot of looks but it didn’t matter to us since we were all really excited, celebrating a successful trip.

The last day! Friday... Sjoerd gave us a tour through Münster.

We learned a lot of useless, yet entertaining facts. His bad jokes seemed to lighten the mood of the many sleep-deprived students. The rest of the day was spent roaming through Münster. In our case, spending some time in bookstores and the botanical garden. That night, we got back on the train and got to Leiden Central station at around 23:00h. This week was a rollercoaster, but every moment was enjoyed. Next year you can count me in again! Also, I came to the conclusion German beer is highly drinkable.

This year’s committee!

If you are a first year student reading this; Save the date for next year! The BRC always takes place in the February holiday and is something you don’t want to miss! Don’t forget to check the box for the BRC on the committee interest form as well. I would like to use this opportunity to thank the committee for all the hard work, I can speak on behalf of everyone when I say it was an amazing week!

Renate de Vreede

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Jumping into the new year Jumpsquare

Chocolate lunch

At the beginning of a new term, every MST student is motivated to study hard. But after a few weeks of studying hard, we are ready for a fun and relaxing activity.

Luckily the CDL members could again count on an activity of the AkCie. This time they had planned a relaxing yet strenuous activity for us: jumping at Jumpsquare.

On Friday December 13th it was finally time for the first activity organized by the FeminiCie. The committee organized a chocolate lunch. All women (and men in a skirt or dress) were welcomed in the Science Club during lunchbreak, where you could eat anything with chocolate you could possibly think of. There were chocolate croissants, chocolate bars, chocolate spread and sprinkles, hot chocolate, brownies, cupcakes and so on…

In the end, there were almost 30 participants, who could all enjoy the chocolate and talk about the ending year just before 2020 started. The committee asked everyone to bring their own mug for the tea and hot chocolate, with the idea of sustainability in mind. It was very fun to see women of all years in the Science Club talking while enjoying the food. It was nice to see all the enthousiasm for the first activity . After everyone had caught up and was full of chocolate, the FeminiCie announced when the Ladies Career Night will be taking place; the 21st of April.

Save the date!

A large group of CDL members traveled to Rijswijk by train. But unfortunately we had to walk for a bit through the pouring rain and were therefore happy to arrive in the warm trampoline hall. We were even provided with dry socks for the jumping. These socks were provided with a non-slip layer on the bottom to make jumping and walking on socks a little safer. Then we received a safety instruction. Then the fun started.

‘‘When our time ran out, a lot of weary heads came out of the trampoline hall.’’

The trampoline hall was equipped with many different trampolines and other devices. There was a foam pit where you could practice new tricks or could try some slacklining. In addition, there was also a large inflated cushion that you could jump into from a platform. In addition to these fun devices, there were also some more challenging devices that the CDL members ventured into. There was, for example, a trapeze where few CDL members were successful. Almost everyone has also tried to jump on a wall from the trampoline. With such large variations of equipment and trampolines, everyone had a great time. The normal trampolines were also pretty busy.

A lot of tricks were practiced, explained and showed. As a result, some CDL members learned some new tricks.

When our time was up, a lot of weary heads came out of the trampoline hall. Fortunately, someone had the fantastic idea to buy ice cream and this caught on well.

Not much later we were eating ice cream with the entire group. After a nice chat, it was time for the group to head back home.

Sterre de Lange

Martine van Rijn

CollectCie lunch The first Wednesday after the Christmas break the CollectCie organized a ‘Pancakelunch’ in the Science Club. Anyone who was interested could come eat some pancakes for a few euros. It was the perfect opportunity to socialize and catch up with your friends after not seeing them for a while during the holidays. We could all share our stories about the new year’s dive (do it for the M.A.T.C.H. Points) and winter sports with each other, and the atmosphere was very cheerful.

‘‘New people kept coming in asking if they could join after all the pancakes were already sold out.’’

The lunch was a big success and everyone enjoyed the pancakes a lot. New people kept coming in asking if they could join after all the pancakes were already sold out.

All proceeds went to the charity ‘Trees for All’, a Dutch charity which protects the environment and bio-diversity by planting trees and restoring forests all over the world.

They also spread awareness about the importance of trees.

For example, they are currently reforesting the forest near the Andes in Bolivia and working with Staatsbosbeheer to repurpose 6,5 hectares from agriculture to natural forest. This way, we were also doing something for the environment!

Veerle Hoedemaker

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Christmas Dinner

Ice skating

December 16th it was finally time for the annual CDL Christmas Dinner. This is a night many CDL’ers are always looking forward to. And just like always the dinner was organized by the AkCie.

After the krokettenlunch of the EC (first year committee) it was time for their next activity, ice skating in Leiden.

On this particular day all the first-year students had an Organic Chemistry exam in the morning, so the ice skating would be a perfect way to destress and relax after concentrating for three hours straight.

But before you can go to the Christmas dinner, some preparation is needed. First of all, a beautiful Christmas outfit must be pulled out of the closet. Many guys appeared in their best suits and the women wore beautiful dresses and jumpsuits. However, some CDL members chose an outfit that was a little more original. For example, a few second year students were dressed as a Christmas tree (lights and all!). An outfit was however not the only thing the people of CDL went looking for. Dates also needed to be found before attending the Christmas dinner. Because of this there were a lot of non-CDL members present, who could enjoy their first ever CDL activity. Other CDL members chose to go with eachother. Some people even let someone else decide by participating in a Date Roulette.

After all the preparations were completed, the festive night could really begin. This year the dinner took place at Woo Ping, a Chinese restaurant in the city center of Leiden. The restaurant soon filled with nicely dressed CDL members. The restaurant was set up with long tables at which the guests could take place. The long tables came in handy, because the dinner was following a shared dining concept. This means that large platters of food are placed on the table and everyone could taste a bit of everything.

This way we could all enjoy the food together.

Following tradition, multiple people gave a speech. First up was the chairman of the AkCie, Quentin, before the first course. Second came the youngest person present, Lucie. After Lucie, the honor was given to the praeses of the CDL, Lara, to address all those present after the main course. And last but not least the oldest person present, Lennard, closed the evening with a final speech.

After the festive meal, the night was far from over. The Christmas dinner was followed by the Christmas party. So everyone left Woo Ping to go to de Hut van Ome Henne.

Here we could all dance and sing to a lot of (Christmas) hits. The next day we could all look back on a wonderful night. Thanks to the AkCie!

Wietse Saalmink

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‘‘Some people stepped on the ice like it was second nature, while other people could barely stand up on their feet.’’

After the exam the first-year students could go to the Thursday drinks to have a beverage, talk a little about the exam and enjoy a nice pizza. After a while, the group of first year students went on the bike to the ice-skating hall, where it was time to put on the ice skates and step onto the ice. Or like we say in Friesland: ‘it giet oan!’. Some people stepped on the ice like it was second nature, while other people could barely stand up on their feet.

It was a lot of fun to skate with everyone and we had an awesome time together. We played tag on the ice, had a snowball fight, skated a few rounds and tried to set a speed record at the speed meter that measured your skating speed.

At the end it was time to release your feet from the painful skates and put your shoes back on. We had a nice cup of hot chocolate with cream (koek en zopie) to end the great evening. It was a nice activity and we had a lot of fun, so EC thanks for this amazing activity!

Jorn de Vries

M.A.T.C.H. Update Last semester the M.A.T.C.H. has been busy. There were a lot of new riddles which had to be solved alongside of multiple activities at which the participating teams could score a lot of points. For example, the city game, game night and the final activity.

Game Night November 25th it was time for the game night. Multiple games were prepared for the teams at which you could score points. Some games were familiar to most, like 30 Seconds and Black Jack. There were also games in which the participants were taken out of their comfort zone a little more. For example, songs had to be portrayed and a birthday party had to be prepared (balloons had to be inflated and a cake had to be decorated) without the use of your hands. There were also some games that needed a little more thought. There were anagrams about MST that had to be solved. There was also a riddle, which the participants had all night for to solve. During all playing rounds, the participants fought hard and many points were collected.

Final activity On February 10th, the M.A.T.C.H. was almost ending.

The tournament ended with a Pub quiz with pizza.

The pub quiz consisted of questions in four different categories: history of Leiden, CDL, chemistry and about the M.A.T.C.H.. But the teams could also earn points in other ways. For example, the teams were given a puzzle piece for each weekly assignment that they had answered correctly. The teams then had to guess what the puzzle said. There was also a team name under each table. And if you sat down with your team at your own table, you earned points again.

‘‘During all playing rounds, the participants fought hard and many points were collected.’’

City game January 10th was the day of the city game. During the city game it was again the goal to collect as many points as possible. But before you could start the real game. A riddle had to be solved in the Burcht. Professor M.A.T.C.H., a dressed up Sjoerd, was also present. With the help of numbers and the elements from the periodic table, letters could be found and you could start the city game. During the city game there were two different routes through which you could collect points. First of all, you had a route where you had to search for chemical images in Leiden. In addition, you also had a route that took us past the board members and members of the M.A.T.C.H. committee.

Every time a new person arrived you could play a game to earn points. That’s how you had to recreate a molecule at Danique. During Lara’s game you had to name all the board names that are painted on the wall in the CDL office. This turned out to be very difficult because only two teams (the Incapablo’s and Haasje Over) could answer this question correctly. And there were many other games. All teams had to make sure to be back at the Burcht before the time was up. Here the teams had one last question waiting for them.

But at the end of the evening it was really time to make up the score and crown the winners of the M.A.T.C.H. 2019-2020. The Enthalpiraten finished in first and they won a M.A.T.C.H. mug, a bag of candy and matches. The Incapablo’s finished second and Haasje Over finished third. Unfortunately, the M.A.T.C.H. has come to an end for this year, but the teams can start training again for next year.

Niels van Silfhout

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Warm up...

When it is freezing outside everyone likes to go outside to go ice skating, build a snowman or to throw snowballs to each other.

There is only one big downside about this fun activities. Afterwards you will have very cold hands and they just will not warm up by themselves. The easiest way to warm up your hands is to take a hot shower, heat them up by using the hot tap or drink a hot cup of chocolate. Unfortunatly, sometimes all these options are not possible. If this is the case, an instant hand warmer is the way to go.

The use An instant hand warmer is a small plastic pillow with a small coin floating through a transparent liquid. If you press on the small coin, the whole liquid will slowly solidify and becomes very warm. If you now hold the hand warmer in your palm, your hand gets warm again. After a while the hand warmer will cool down but stays solid. If you put the used hand warmer in a bowl with boiling water, it liquefies. Now the hand warmer can be used again. This is a small summary how the product is used, but how does it work?

The emitting and absorption of heat In chemistry reactions can be divided in two different groups. There are endothermic and exothermic reactions.

Endothermic reactions are reactions that absorb energy, while exothermic reactions release energy.

So, in our case, the reaction that happens when the hand warmer heats up is an exothermic reaction. When the hand So, in our case, the reaction that occurs when the hand warmer heats up is an exothermic reaction. At the moment the hand warmer is put in a bowl of boiling water, it will absorb energy.

This means this reaction is an endothermic reaction.

“...the reaction that happens when the hand warmer heats up is an exothermic reaction.”

Supercooling Most of the time this type of hand warmer contains sodium-acetate tri-hydrate which is a supercooled liquid[1]. Supercooling is the process of lowering the temperature of a material under their melting point without becoming a solid. In the case of sodium-acetate that melting point is at 58°C. So, sodium-acetate will be a solid at room temperature. However, supercooled sodium-acetate is highly stable when it is melted in boiling water and then cooled down[2].

Supercooled liquids can crystallize when a small crystal nucleus is formed where the crystal can start growing.

This nucleus can be formed when work or a little particle is added. Also, when the temperature is cooled down even more it is also able to recrystallize[3].

“...so the emitted heat from the recrystallisation is absorbed by your hand. “

Super cool with a super cooling water You may have seen a movie on social media were they have a bottle of liquid water, but when they slam it on a table it completely freezes. In another video they pour the water out of the bottle and a small mountain of ice will form. This type of process is very similar to the hand warmer. The liquid water that is used in these type of videos is very pure. This way there is less chance that a nucleus is formed when the water is cooled down. This pure water is cooled down without moving it in a freezer. There is no place where the liquid water can start crystallizing, so it will stay a liquid. In other words, it will be a supercooled liquid. When the bottle of water is slamed on the table or the water is poured out a nucleus will form in the water and the crystallization will start. So, if you want to You can form super cool ice mountains with super cooled water impress your friends with a super cool trick: buy a bottle of the purest water you can find in the supermarket, put it in the freezer and just wait a few hours. After that, just slam it on the table and let minds be blown[4].

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... or cool down A small part of coin in the hand warmer is broken off when it is pressed. This small part starts the whole crystallization, which is a highly exothermic process.

On the image on the right this crystallization of sodium acetate trihydrate is shown in a round bottom flask.

As mentioned before, with an exothermic reaction heat is emitted, so the emitted heat from the crystallisation is absorbed by your hand. Subsequently, the crystallization is completed and the hand warmer stops emitting heat. When the hand warmer is added to the boiling water it melts again (heat is added so this is a endothermic reaction). Then it will become a supercooled liquid when it cools down again. Now the handwarmer can be re-used.

Joeri Schoenmakers

References [1] howdoesstuffworks. (z.d.). How do sodium-acetate heat pads work? Geraadpleegd op 10 februari 2020, van https:// home.howstuffworks.com/question290.htm [2] Dietz Jr, P. L., Brukner, J. S., & Hollingsworth, C. A. (1957). Linear crystallization velocities of sodium acetate in supersaturated solutions. The Journal of Physical Chemistry, 61(7), 944-948.

[3] Russo, J., & Tanaka, H. (2012). The microscopic pathway to crystallization in supercooled liquids. Scientific reports, 2, 505.

[4] Debenedetti, P. G. (2003). Supercooled and glassy water.

Journal of Physics: Condensed Matter, 15(45), R1669.

Instant cold pack It is nice to heat up with an instant hand warmer when you’ve finished your outside activity.

However, sometimes this outside activity didn’t go as planned and you have injured yourself. For a lot of injuries it is the best to cool it immediately, so you need some ice fast.

There are a lot of places where you can work out and don’t have a freezer nearby, so where do you need to get your ice from then? For these moments an instant cold pack is perfect!

An instant cold pack is a plastic bag which contains mostly water, sodium acetate , potassium chloride and potassium nitrate. The water and salts are separated from each other with a plastic membrane. In the water the salts are stored in a separate small bag or in little balls. When the instant cold pack is used the small bag or the little balls need to be broken.

The salts will mix with the water and dissolve. The salts in the cold pack are selected due to their high (negative) dissolving energy, causing the cold pack to cool down by a lot. In other words, the dissolving of the salts is very endothermic. The cold pack can now be applied to the injury to cool it down. [1]

“The salts in the cold pack are selected due to their high (negative) dissolving energy, causing the cold pack to cool down by a lot.”

This type of cold pack isn’t designed to be reused, so it will be thrown away after use. However, in theory it could be reused.

If the liquid from the used cold pack is heated the water will evaporate. When all the water is gone the salts will be left over and can be used in a new cold pack.

Joeri Schoenmakers

References: [1] Donnelly, W. R. (1978). U.S. Patent No. 4,081,256.

Washington, DC: U.S. Patent and Trademark Office.

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Experiencing Universities in the North

Oslo, Norway In early August I started my adventure as an Erasmus+ student at the University of Oslo (UiO) in Norway. Currently, I am doing the master Chemistry and Business Studies at Leiden University and I chose to do the 20 ECTS intended for my elective courses at a university abroad. I took Environmental Chemistry and Inorganic Structural Chemistry and I decided to do a Norwegian Language course. The way of teaching at the University of Oslo is quite similar to what I’m used to in the Netherlands, however there are less lectures (usually 2-4 hours per subject) and the subjects are a semester long. In addition, both my courses had one-hour oral exams at the end. The concept of oral examination for chemistry courses was completely new to me and that was quite exciting.

“The way of teaching at the University of Oslo is quite similar to what I’m used to in the Netherlands” Aside from studying, I decided to volunteer in the faculties coffee bar and I joined the local student volleyball club.

Norwegians are very passionate about sports and the outdoors and therefore in clubs related to this the feeling of being part of a community is really high. I met most of my Norwegian friends through the volleyball association, I met my fellow-international friends during the intro-week of UiO as they were part of the same Buddy Group as I was.

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During my five months in Norway my friends and I managed to do a lot of trips to the Fjords on the West-Coast of Norway and to Northern Norway to experience the country’s beauty.

Mostly we were lucky and had good weather, but Norway can be quite rainy too. Though, with proper clothing you can still go outdoors and enjoy nature any time you like.

The Norwegians think of it that way too according to their famous saying: “Det fins ikke dårlig vær, bare dårlige klær” which means, “There is no such thing as bad weather, only bad clothing”. Living by that rule, my friends and I did a lot of hikes because Norway is a great country for hiking.

“There is no such thing as bad weather, only bad clothing”.

However, as the days became shorter, darker and colder the trails became more and more slippery and we chose to go to Christmas markets instead. We saw the first snow in early November and all the Norwegians went out on the weekends to do some cross-country skiing. I decided to stay in Oslo for Christmas and I was asked to spend a traditional Norwegian Christmas eve with my Norwegian flat mate and her family.

That involved eating pinnekjøtt (lamb rib), one of Norway’s traditional Christmas dishes, and danced around the Christmas tree whilst singing Norwegian Christmas songs.

With that my Norway experience was complete. Norway is a great Scandinavian country both for travelling and studying!

Iris de Bruin

Stockholm, Sweden Around one year ago I arrived in Stockholm for my half year adventure of studying at another university, meeting many new people, discovering a new culture or actually many new cultures and discovering the beautiful nature of Sweden. An experience I would definitely recommend to everyone!

I studied at the university Kungliga Tekniska högskolan (KTH) where I took four courses and a Swedish language course.

Upon arrival KTH had made everything as comfortable as possible. They organized two weeks full of introduction activities were we had the opportunity to meet our fellow Erasmus students. The days were short and dark, so it was nice to spend the time together doing pub crawls, baking typical Swedish cookies, going to the sauna and several more traditional Swedish activities.

“The days were short and dark, so it was nice to spend the time together...”

had to dive into literature, use the lectures, talk to specialists and come up with a possible solution. Besides, we had to do assignments and you could decide yourself which one you wanted to do and by doing more assignments you could increase your grade. This educational system was applied to almost all my courses and really motivated me to study and dive into topics which got my interest, instead of studying the topics you have to study.

“For me the way of teaching was super motivating.”

Besides the fun studying experience, I had lots of free time to make new friends and wonderful trips. The country is so beautiful and the inhabitants of Stockholm directly made me feel at home. I did not only get to know the Swedish culture but the Erasmus program gave me the opportunity to meet many new cultures and lovely people!

Marije de Vos

Trondheim, Norway

At the same time my first courses had started. I directly figured that the courses were really differently organized at KTH than I was used to in the Netherlands, both the content of the courses and the educational system. I did a course on Biopolymers, and during this course we did not only learn about the properties of biopolymers, but we also learned about their impact on society. We looked into the current problems of plastic waste and had discussions about the consequences of the products we, as scientist, can develop.

When I was asked if I wanted to write something about my time abroad, I was immediately excited. This is because I love to talk or write about it. Last semester I studied at the NTNU, short for Norges teknisk-naturvitenskapelige universitet, in Trondheim (Norway) for my minor and this place was the perfect fit for me. I loved that I could go away every weekend, especially to spend my weekends outdoors in the nature. The university has a special offer to rent a cabin for 4 euros per person per night, which is great because a cabin trip is a good way to bond with your friends! One amazing memory is the time we were in a cabin in the mountains where we played in the snow the whole weekend, building an igloo! Besides cabin trips I made some road trips and went to some places more to the north.

“... a cabin trip is a good way to bond with your friends!”

During the same quarter I also did the course Waste Management. For me the way of teaching was super motivating. There was no exam in the end, but we had to do a project for which you could choose a topic of your own interest within waste management. For this problem you

The study load inTrondheim is the same or even a little bit lower as in Delft and Leiden. I followed the following courses with 7.5 credit each: Solar Cells and Photovoltaic Nanostructures, Molecular Modelling, Electrochemical Process and Energy Technology and Nuclear Magnetic Resonance Spectroscopy.

At the NTNU you follow the courses for one semester long and at the end there is an exam period of almost 1 month.

“... just go, experience the country and make as many trips as possible!”

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Studying abroad was amazing! I expected that it would be challenging to live abroad in a complete different environment, but it turns out it was not challenging at all. It was nice to be out of your comfortable bubble and organize and do everything on your own. I made some good friends all over the world and we already have planned our next trip together now that we are all at home again! Another thing where I am grateful for is that my English has improved so much, and that was my main reason to go abroad. If you like to hike and be in nature I really recommend to go to Norway.

If you are more a party person, than Norway is maybe not the best option. The last thing I want to say for the people who are planning to go abroad: just go, experience the country and make as many trips as possible!

Lotte Vijverberg

Helsinki, Finland Studying abroad had been my plan since I started studying MST. My love for Norway and Sweden made it clear that I wanted to study at a North European university, and I was drawn to Finland because I had never been to this country before. I decided to apply to Aalto University in Helsinki, and I am incredibly happy with this choice!

When I received the email that stated that I had been accepted to Aalto University, I was so excited! But at the same time I got a little stressed, because there is so much to arrange before departure. I had to hand in documents to international office in Delft and at Aalto, start searching for a room and pick out courses that I would like to follow. Fortunately I managed to do all of this on time, and on the 30th of August I was ready to step into the airplane to officially start my adventure in Finland.

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I was very happy to find out that an international chemistry students kickoff event took place on my first day in Helsinki.

I did not know anyone of course, so this was the perfect moment to get to know some fellow international, but also Finnish students. In the following days an orientation program was organized, so I met a lot of nice people, who I ended up spending most of my time in Finland with.

The subjects of the courses that I took varied a lot, from organic chemistry to functional inorganic chemistry, metallic material, to sustainability in environmental engineering.

Adjusting my program to my own interest was very refreshing. Even though all of the courses were from master degrees, I did not struggle with the level. The lectures were quite challenging, but the exams turned out to be very easy and it was not hard to pass the courses at all.

“The northern part of Finland is absolutely breath taking...�

Because of the relatively low level of the courses, I was able to do a lot of fun activities with my friends. We went on a large number of trips to cities in Finland, the lake region, Tallinn, Stockholm, Saint Petersburg and of course Lapland! The northern part of Finland is absolutely breath taking in the winter, and going there was an absolute must for my friends and I. We made a tour with a husky sledge, went ice fishing and spotted the northern lights!

I would absolutely recommend studying abroad to any one in doubt! It is amazing to get to know so many new international people and it is very educational to live in another environment for a while.

Maartje Zweers

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Working side-by-side with our customers, we develop value-added, customized solutions that make them more competitive. Our specialty chemical solutions combine the finest technology and ingredients with the knowledge and know-how of our highly experienced and talented team of operators, scientists and engineers.

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@AlbemarleCorp

To apply, visit albemarle.com/career

exploring the real world Visit to Suiker Unie First years excursion

the engineer, the measures Suiker Unie took to deal with the changing nitrogen regulations and diverse other cases that Suiker Unie encounters.

We as first year students were allowed to visit Suiker Unie on Friday the 20th of december 2019. Suiker Unie is a producer of granulated sugar and is one of the largest sugar producers from beets in Europe. Accompanied by the Chemisch Dispuut Leiden and the Technologisch Gezelschap we took a closer look at the factory of Suiker Unie in Dinteloord.

The excursion started with a presentation about the company Suiker Unie. Something that I found quite interesting is the emphasis that was put on sustainability. The company gives a lot of attention to the most optimal use of the sugar beets that are delivered to the factory. Besides the fact that the beets are used for the production of sugar, the residual products are used as biomass for energy.

“The tour was provided by three friendly guides who exhibited the process from sugar beet to sugar cube.�

Following the presentation we received a tour through the factory that handles the production. The tour was provided by three friendly guides who exhibited the process from sugar beet to sugar cube. The trip began where the beets were delivered to the factory. Lorries full of beets are deposited on the assembly line, after which the beets are washed and chopped to small pieces. Thereafter, these pieces are reduced to a sort of juice. Here the purification process begins. This part of the tour led us to a great number of reactors. The guides told us about the processes that are located in the various reactors and how the juice in the reactors eventually crystallizes.

After the end of the tour we got the possibility to ask questions to a chemical engineer who works for Suiker Unie.

Consequently, the group discovered more about the study of

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In general the visit was very rewarding. Personally, I found it truly wonderful to look deeper into the factory of Suiker Unie.

I would like to thank all the people involved that organized this excursion.

Yordi Beelen

Albemarle excursie Tuesday January the 14th a group of second year students gathered at the Gorlaeus building in Leiden. From here we took the bus that would bring us to Albemarle. The location we would visit is located in Amsterdam. This excursion was organized to supplement the course Introduction to Catalysis, since Albemarle produces catalysts which are used in the refinery of oils.

Upon arrival we all received a guest-badge. The group was welcomed with lunch, during which we had a talk from Eelco Vogt, the head of R&D. He told us about Albemarle as a company, what it is like to work there . During his presentation he showed us two different catalysts which are produced by the company. The catalysts are used to desulfurize the oil and also to have a higher yield of propylene and other light-weight molecules. This is of course beneficial, as these are the more demanded products in the chemical sector. It was very interesting to see how the theory we just learned at Introduction to Catalysis was brought into practice at this company.

Young Capital Next workshop It was time to put ourselves out there and to learn some new things. On friday the 22th of november an important part of our career was discussed: job application. Young Capital Next stopped by to give us a workshop where they wanted to prepare us for this difficult step. As ‘De Jeugd Van Tegenwoordig’ has told us before: “a good start is half the job”. Two enthusiastic young women helped us with short examples and gave us short training on how to give a “killer first impression”.

The first step was to Google our neighbour. This was to make ourselves conscious about the information that is readily available about us on the internet. Do you quickly encounter photographs of you partying? Those pictures of you can give an unprofessional image to the recruiter who is examining your curriculum vitae. Further they told us that a cv should not be a lot longer then one or two pages. A longer cv can give the impression that you are not able to be concise in your distribution of information. It can also indicate that you are less competent in making a distinction between important and unimportant cases. They were very clear that longer cv’s are often not read.

After the talk from Eelco we had to dress up in a protective suit, security goggles, and a helmet. The next item on the programme was a tour around the site. We were split in two groups and my group first got a tour of the factory. We walked along the whole production process of the catalysts where we could see how they carried out the process on a large scale.

It was amazing to see how much they actually produce, and very interesting to actually be able to see the factory and the process from the inside.

“Here they tested the efficiency of the catalysts, and they tried to accelerate its degradation.”

The next thing on the list was your motivation letter. The focus point was a so-called “cover letter”. They showed us an example motivation letter which repeated the corresponding cv in narrative form. The way they spoke about the letter made it very clear that this was not the way to do it. The recommendation that was given is to take the chance to tell more about yourself and to give your inherent motivation.

So, what makes you yourself and why is the Job perfect for you as a person and not as an academic or skilled person.

After the informative and engaging workshop I think we all should fear less for the job application process. Because we need to think about this in a couple of years. I know for myself that I am a bit better prepared.

Sjoerd Rieken

After we had seen the factory, we swapped with the other group to take a look at the R&D facilities. Here they tested the efficiency of the catalysts, and they tried to accelerate its degradation. This research enables them to make an educated guess of how long it would last at their clients. Afterwards, the whole group had some drinks and the opportunity to talk to Eelco and ask questions.

At the end we walked together to the metro station to travel home. The company was very open and welcoming. It is exceptional that we were allowed to walk around and see the whole process, this is not something that happens at every company. All in all it was a very interesting afternoon, and a great opportunity to take a look inside a chemical company.

Marouscha Puister

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Lunch lecture on apparent sustainability I think we have all asked if winter is still coming. I certainly did multiple times. Especially with the seemingly everlasting winds in the Netherlands it is just a very long autumn. Yes, it is fair to say that climate change and our impact on this world are noticeable. The increasing awareness of these problems have an impact on the economy. So, companies are trying to get a piece of this emerging “green” market. Project Green stopped by to tell the students of the Science Faculty about how companies use marketing to influence the consumers.

Robbert-Jan Knoppers, who presented the lunch lecture, is the marketeer for Project Green. Previously his profession was utilised by heavy weight companies like Shell giving him a good insight in how these companies go to work. Since 2010 he has put his effort in improving the green market.

He started his presentation asking us who makes a decision based on sustainability at least once a week. It was interesting to see that slightly more than sixty percent of the audience does this. Supposedly about fifty percent of the general population makes those decisions from time to time, that is a lot as I say myself. No wonder companies want to influence those people. I will give an example of such later on.

Further he talked about how the impact on the environment is determined. Often the emissions of the last production process are published as the emissions of a product.

These numbers are not necessarily incorrect, but they are misleading. Products do contain embedded emissions. These are the emissions that are emitted of all processes behind the last production process. The parts and materials that arrive at the factory have likewise emissions. So, to give a true and final number to the impact of a product, one needs to do a life cycle analysis. Such an investigation explores every part of the production chain rather than the very last step. A striking company example of using numbers to appear more

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sustainable is Coca Cola. A sustainability report that Coca Cola published in 2011 tells us that they use 35 liters of water for every half liter of cola. However, the company publishes much lower numbers, one to two liters, on their websites which most of us will see.

“Often the emissions of the last production process are published as the emissions of a product. These numbers are not necessarily incorrect, but they are misleading...”

Robbert-Jan Knoppers made it clear that we need to be aware of numbers that companies show us to promote certain products. This apparent sustainability is in my opinion dangerous as it diverges us from really changing the market to a more sustainable future.

Pepijn Lammers

Research group: MolPhys Molecular Physiology is a research group at the Leiden Institute of Chemistry, headed by Prof. Mario van der Stelt. The research aim of the MolPhys group is to design, synthesize and apply new chemical tools to answer important biological and medical questions. Activity-based protein profiling, assay development, chemical proteomica and advanced molecular biology techniques are used to determine the selectivity and activity of small molecules in physiological and disease processes. The focus is on cancer, metabolic- and brain disorders.

Research According to their website the current projects of the Molecular Physiology group focus on kinases and proteins of the endocannabinoid system. In a multidisciplinary research line, they combine organic and medicinal chemistry with molecular biology and chemical biology. They use computational chemistry together with activity-based probes for compound profiling and optimization. In (inter) national collaborations with biologists and pharmacologists they test their molecules in preclinical models of disease.

Detection and modulation of endocannabinoid biosynthesis Endocannabinoids are endogenous signalling lipids that activate cannabinoid CB1-receptors. Continuous stimulation of the CB1-receptor is associated with nicotine addiction, obesity and the metabolic syndrome (all major risk factors for illness and death in Europe). The CB1-receptor antagonist rimonabant was effective in obese patients, but withdrawn from the European market due to unacceptable psychiatric side effects. This highlights the medical need to modulate the endocannabinoid system in a more specific manner. In this research line we develop assays, mass spectrometry methods and activity-based probes to determine the activity of the endocannabinoid biosynthetic enzymes. We use different lead finding strategies, including high throughput screening, to identify and optimize molecules to control the activity of the enzymes in preclinical disease models. This project is funded in part by a grant from the Dutch Research Council Chemical Sciences (NWO-CW).

Development of biomarkers for target engagement of GPCRs Cannabinoid CB1 and CB2 receptors, which are activated by Δ9-tetrahydrocannabinol (THC), the main active ingredient in marijuana, belong to the class of G-protein-coupled receptors (GPCRs). These receptors are extensively studied for their therapeutic potential. We have recently reported the identification of a new class of highly potent and selective CB2 receptor modulators, which were active in in vivo models of neuropathic pain without inducing CB1-mediated psychotropic side effects. The aim of this research line is to develop biomarkers to study target engagement of the CB2 receptor in preclinical disease models. This project is performed in collaboration with Dr. L. Heitman and funded by a grant from the Dutch Research Council Chemical Sciences (NWO-CW).

Development of selective kinase inhibitors to treat leukaemia In collaboration with the Netherlands Cancer Institute (NKI) we have identified kinase inhibitors that potentially can be used for the treatment of acute myeloid leukaemia. The goal of this project is to improve the compounds in a hit optimization program. This project is executed under the framework of the Cancer Drug Discovery Initiative, a public private partnership of Leiden University, Netherlands Cancer Institute and Pivot Park Screening Centre.

For more information about the Molecular Physiology research group check their website: https://www. universiteitleiden.nl/en/science/chemistry/molphys/research

Labtour MolPhys On January 14th the CDL organized a labtour of the Molecular Physiology (MolPhys) lab in the lunchbreak. We gathered in the Gorleaus building with a small group of people where Anthe Janssen, Postdoc at MolPhys and a former CDL member gave us a short introduction about the research group. The research of MolPhys used to be part of the Bio-organic Synthesis research group, but they split into a separate research group. After the introduction we visited the MolPhys labs. Unfortunately, we could not see the biology labs from the inside because these labs have to be very sterile, but it was still clarifying to see where the MolPhys team do their practical research. During the labtour it was emphasized that MolPhys is a very versatile research group where different fields of science meet, especially chemistry and biology.

The whole tour gave a proper overview about the research at MolPhys and what to expect if you ever choose to do an internship at this group.

Lise van den Bos

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BEP at Molecular Physiology Last year, I did my Bachelor End Project (BEP) at the research group Molecular Physiology (MolPhys). MolPhys is a very diverse group, where both MST, LST and Chemistry students can do an internship. Mario van der Stelt, professor of Molecular Physiology, leads this mixed group, where both chemical and biological research is performed. I wanted to do a lot of chemical biology in my BEP, because I wanted to know if I would like to do this kind of research. I did my research in the field of the endocannabinoid system, by testing some of the compounds other students had made.

The endocannabinoid system is a complex neuromodulatory network, located in both the peripheral and the central nervous system. The endocannabinoid system regulates among other things appetite, immune function, energy balance, learning and memory. It plays a role in for example anxiety, depression and psychiatric disorders. Understanding how the endocannabinoid system works is very valuable, to exploit the system as a therapeutic target. The endocannabinoid system consists of two receptors, CB1 and CB2, their endogenous agonists (endocannabinoids), anandamide and 2-AG, and the proteins and enzymes that regulate the endocannabinoid levels at the receptors. One of these enzymes is PLA2G4E. PLA2G4E is a membrane associated serine hydrolase, that can synthesize the precursor of anandamide. Using inhibitors, activity of PLA2G4E could be studied. By gaining a deep insight into the inhibition of PLA2G4E, more information could be gathered about possible treatments for different disease profiles.

Figure 1 Schematic overview of ABPP workflow. In the first reaction, competitor is added. In the second reaction, probe is added.

During my BEP, I did two different projects. The first experiment was the optimization of a fluorescence polarization assay. Activity based protein profiling (ABPP) is a technique used to measure the relative activity of the enzyme, using an inhibitor and a probe. First, the enzyme is incubated with a certain concentration of inhibitor. After this incubation, probe is added. The probe can react with the enzymes that still have an empty active site. A probe thus binds on the same site than the inhibitor. ABPP can be done both on gel and in a fluorescence polarization assay. When performing ABPP, different concentrations of inhibitor can be used, to create a dose response mechanism.

Figure 2 An overview of differences in emission during fluorescence polarization. When probe is bound to PLA2G4E, there is no depolarization. Probe that is not bound depolarizes the light.

Fluorescence polarization is a technique which uses polarized light. This polarized light is excited on the samples in the wells, and the fluorescence intensity of the emission is measured. When the probe is bound to the enzyme, it cannot rotate freely and therefore the polarized light will stay polarized. When the inhibitor is bound to the enzyme, the probe cannot bind and can thus rotate freely. This will cause the polarized light to depolarize. The more inhibitor is bound to the enzyme, less probe is able to bind and therefore the polarization will be lower. I optimized this assay for PLA2G4E, by adding for example detergents and other proteins to the lysate mixture to improve the solvability of the inhibitors, and to prevent them from sticking to the side of the wells. Other changes made were for example the concentration of probe that was used, or the pH values. Using this new assay, I tested some potential inhibitors for PLA2G4E on their potency.

The second experiment I have done is determining the potency of inhibitors on its family members, PLA2G4B, PLA2G4C and PLA2G4D. Because the PLA2G4 family members have a lot of structural properties in common, it is valuable to know whether the potent PLA2G4E inhibitors are selective for PLA2G4E relative to its family members.

Therefore, the most potent inhibitors found for PLA2G4E in earlier research were used to assay the potency on PLA2G4B, PLA2G4C and PLA2G4D. This experiment was done using gel ABPP. From this research, it was seen that some inhibitors are very selective, and others are not. I investigated whether structural groups would cause the inhibitor to be selective or not and from that, I could suggest new structures for inhibitors that are both potent and selective. Unfortunately, my time was running out at the group and I could not synthesize them, but that may be something for further research.

During my time at MolPhys, I have learned a lot about how chemistry can be used in biological assays, and that I really liked to combine those two. It was a nice group to work in, the atmosphere was great and of course I enjoyed doing my research there!

Danique van Workum

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Meet the CollectCie

The CollectCie is among the youngest committees of the CDL. Founded with the goal to help a good cause, each year, the members are tasked with picking out a charity and filling the year with fundraisers to raise money for said group. This year, the CollectCie has chosen the charity; Trees for All. ‘’Trees care for us, and that’s why we care for trees”. This is the motto of Trees for All, a charity focused on the planting of new trees and preservation of already existing forests.

They do this in the Netherlands and abroad, and have been doing so since 1999. Besides protecting and adding to our forests, they also offer carbon offsets of all sizes, ranging from compensating for a flight to making companies carbon neutral. They do this by calculating how much of their forests and projects are needed to compensate for your emissions.

Trees for All has planted over 170.000 trees in 2018, and over a third (60.744 to be precise) were planted in the Netherlands, and the amount of trees has increased with large amounts every year. Nearly 40.000 tons of CO₂ has been compensated for in 2018 as well. One of their older projects, reforestation in Malaysia, has been so successful that they are not allowed to plant any more trees and now nature must take over.

“Nearly 40.000 tons of CO2 has been compensated for in 2018 as well.”

This charity focuses on sustainability which is one of this years’ main focusses of the CDL board. This way the CollectCie also contributes to this goal.

With the closing of the Gorlaeus’ Cafeteria, the lunch options for students were largely limited. Because of this, the CollectCie’s first event this year was our pancake lunch. The first Wednesday after the Christmas break, 30 students came to the

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Science Club to enjoy some delicious homemade pancakes, with syrup and powdered sugar as toppings to boot! The event was a huge success, with 84 pancakes sold and over €65 made.

The CollectCie this year has four members. Danique is the QQ of the committee and oversees communication between the members and the CDL board.

The secretary, Anthonie, is in charge of all communication, both with the CDL members, and with any outside parties who the commission needs to contact. He also takes notes during the meetings.

The treasurer Mädchen takes charge of all financial matters, both with regards to expenses and proceeds.

The president, Kees, is the head of the commission. He plans and leads meetings, oversees all matters, and makes the final decision when necessitated.

The CollectCie is looking forward to more successful events in the future and hopes these will be as greatly attended as their first one. This way the CollectCie can contribute to a sustainable future by giving the money to Trees for All.

Kees Luijendijk

CollectCie over the years Last year the CollectCie raised money for the charity; Edukans. This charity focuses on better education for developing countries. The commission collected around €200.

In the academic year 2017-2018 the CollectCie raised more than €300. As charity they chose the Universitair Asyl Fonds (UAF). Since 1948 UAF supports refugee students in their studies and in finding employment in the Netherlands.

Vroeger was alles anders ...of toch niet??

Laat ik me eerst even voorstellen voor de CDL-leden die nu hun bachelor MST doen: ik ben Hilde Zwaan en ben sinds ruim een jaar studieadviseur binnen de masteropleiding Chemistry en Life Science & Technology. Maar ik was ook ruim 20 jaar geleden praeses van het CDL bestuur en mij is gevraagd om een stuk te schrijven over welke verschillen ik zie tussen het CDL van vroeger en nu. Tja, waar zal ik beginnen?

Ik was vooral in shock tijdens de CDL CoBo van 17 september 2019.

Schenkdames? (Huh?) Brassen?!! (Ik kende dat hele woord niet eens!)

Keihard tegen elkaar verenigingsliederen zingen?

In de eerste alinea is er nog een ander verschil aan de orde gekomen: de wekelijkse borrel in de Borrelbunker. Na college om 16 uur ging je direct door naar de kelder van het LCP en plofte je neer op één van de oude banken. Nu is er de wekelijkse borrel in de Science Club waar ik ook regelmatig te vinden ben. Dit is zeker ook een leuke ruimte en gezellige sfeer. Maar toch… die Borrelbunker met haar eigen wekelijkse CDL borrel en de CDL-kamer in de kelder van het LCP. Mooie tijden!

“Er is tamelijk wat veranderd. Maar ik zie nog steeds een bruisende, gezellige vereniging.”

Met onze CoBo zaten wij in ‘onze’ eigen Borrelbunker, beneden in de kelder van het LCP. Er waren wel wat zusterverenigingen aanwezig, die met een biertje, zonder zingen of brassen, ons kwamen feliciteren. Maar er waren ook wat betrokken stafleden, promovendi en andere medewerkers uit het Gorlaeus aanwezig, zoals de Kees Schoonwater van die tijd. Misschien werd het CDL-lied een keertje gezongen (of eigenlijk, het oude CDL lied: weggestemd in de historische ALV van 19 mei 1998 en officieel benoemd als “geen CDL lied”. Ten opzichte van 2020 is dit historisch omdat het huidige CDL lied “CDL is mijn dispuut” als HET officiële CDL lied werd verkozen), maar meer ook niet!

Liederen werden zeker gezongen tijdens weekendjes weg (Texel, Veluwe) of tijdens de reizen: de Belgiëreis voor tweedejaars en de buitenlandreis voor de derde- en vierdejaars. Jawel, de buitenlandreis was geen Japan, Genève of Milaan, maar - tromgeroffel - na België gingen we onze grenzen verleggen met een busreis van vijf uur in het Ruhrgebied van Duitsland (!).

Wat dat betreft, is er wel het een en ander verbeterd!

Nog een paar andere activiteiten van toen: een filmavond in een van de zalen van de schotel, een karaokeavond in een kroegje in de stad en uiteraard was er het PAC symposium.

Maar toen was het PAC een 2-daags symposium met een overnachting in een sportcomplex en een groot feest op de eerste dag. Dit had ook wel een nadeel: na veel gefeest en met weinig slaap moest je alle lezingen op de tweede dag volgen. Gelukkig was er toen ook koffie. De ONCS, excursies naar bedrijven en carrièreavonden waren er toen ook.

Uiteraard was er toen ook de Chimica maar mèt haar eigen soap “Natriumstearaat”. Een soort roddelkatern binnen de Chimica, waarbij liefdes tussen CDL-ers en laatste gossips onder fictieve namen (maar met goede beschrijvingen van uiterlijke kenmerken) aan het licht kwamen.

Conclusie: er is tamelijk wat veranderd. Maar ik zie nog steeds een bruisende, gezellige vereniging. Sommige dingen veranderen gelukkig nooit. De essentie van het CDL is hetzelfde gebleven. Nog even terugkomend op de CoBo: Misschien moet ik met mijn tijd meegaan… Misschien kan ik Rob van Waarde zo ver krijgen dat we met de volgende CoBo het “geen CDL lied” gaan zingen, wat wij vaak hebben gezongen met feesten. Om de goede, oude tijd te verenigen met de huidige. Wie weet!

Hilde Zwaan

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The ice cold science of Disney’s Frozen Toy stores nowadays are flooded with Elsa and Anna action figures, movie posters, Frozen lunch boxes, Olaf onesies and many more items related to the immense popular Disney movie ‘Frozen’.

Not only children are obsessed with the new and modern Disney Princess movie, also grown-ups are part of this ice-cold hype.

However, we as scientists, watch movies with a bit of a sharper eye (respect for those who have watched Breaking Bad without discomfort). After watching Frozen multiple times, some questions started to come to mind, such as ‘how much power does Elsa really have?’, ‘do the moviemakers know the properties of H2O?’ and what about the visualization of the film?! And that’s how I can perfectly combine my two most nerdy interests: Disney movies and science.

Spoiler Alert I expect that most readers know the story of Frozen, but for those who don’t: Frozen is a story based on a fairytale of Hans Christian Anderson, the Ice Queen[1]. Anna and Elsa are princesses of the Northern Kingdom Arendelle, inspired by the Norwegian fjord Nærøyfjord. After their parents died, Elsa became Queen of Arendelle at a very young age. She also has the magical power to freeze things, but she cannot totally control her magic. The rest of the story includes a lot of ice, twelve brothers, a grumpy but handsome Scandinavian guy on a reindeer, a melting snowman and some sticky tunes. If you are interested in the whole storyline, just ask a random 9-year-old.

Power Princess One of the key scenes of the movie is the part in which Elsa accidently freezes the whole Kingdom of Arendelle.

In 2014, a master student from the University in Hamilton, Canada, calculated the amount of power required to freeze this amount of water using a Carnot refrigerator[2]. First, he calculated the mass of ice covering Arendelle by using the total surface area and estimating the density of ice-covering.

He calculated 9.9x1013 grams of ice which equals 5.5x1012 moles of ice. By using the Isobaric Molar Heat Capacity of water and the total enthalpy change, he estimated that the work required by the Carnot refrigerated needs to be 5.8x1015 Joules in order to freeze the entire fjord! This is the same amount of energy released by the Hiroshima nuclear bomb MULTIPLIED BY 115! This is almost enough to provide the Netherlands with energy for a whole year[3]. Here, I see a good solution for the rising global energy demand…

Devastating Drama

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By freezing the whole kingdom, Elsa caused both a social isolation as well as an economic disaster for the inhabitants of Arendelle, because all the ships were trapped in the fjord.

As water reaches 4°C it starts to crystalize and when it is cooled to 0°C, the density is reduced by almost 10%[4]. This means that ice will float on water, a property of H2O the moviemakers did understand, referring to the first scene

of the movie. However, later when Elsa freezes the whole kingdom and thereby trapping the ships, they ignored the expansion of ice. The expansion would cause the wooden boats to be crushed by the ice, which would make the film even more dramatic. On top of that, enchanted frozen Anna should be 10% larger than normal human Anna.

Frozen Fractals The phase transition from water to ice also leads to the formation of six-sided ice crystals with a hexagonal symmetry.

When Elsa constructs her own castle out of ice, she also makes use of this beautiful pattern. She even includes the mathematic term ‘fractal’ in her song: “My power flurries through the air into the ground My soul is spiraling in frozen fractals all around …”

When we look very closely to the animated crystals in the movie, we can indeed recognize a neat six-sided symmetric crystal structure. Looking at a real crystal, we can also identify spikes on the end of the snowflakes with a 60° angle which maintain the hexagonal structure. However, the interior spikes of Elsa’s snowflakes are much smaller and thereby do not have a hexagonal structure which invalidates the term ‘fractals’.

Fortunately, at the end of this heartwarming story, Elsa is able to thaw the whole kingdom and everyone lived happily ever after. But wait... what about Olaf?! He survives because Elsa made him his personal flurry, but how does that work? If the cloud indeed regenerates itself, perpetual motion exists, but why didn’t Elsa make Olaf out of that stuff?

Countless questions about this story remain unanswered.

However, I believe that we, as scientists, are able to reveal the secrets of Disney because we all have one shared characteristic: we never let it go (but we do like warm hugs)!

Christine Visser

References [1] Walt Disney Animation Studios, Frozen, 2013.

[2] Goldberg, A. (2014). Powering Disney’s Frozen with a Carnot refrigerator. Journal of Interdisciplinary Science Topics, 3, 1-3.

[3] Centraal Bureau voor de Statestiek. (2019, December 13). Energy balance sheet: supply, transport and consumption.

Retrieved from: https://opendata.cbs.nl/statline/#/CBS/en/ dataset/83140ENG/table?dl=A945 [4] Harvey, Allan H. (2017). Properties of Ice and Supercooled Water. CRC Handbook of Chemistry and Physics (97th ed.).

ISBN 978-1-4987-5429-3.

Education in the labs Since he second semester has already started whilst I am writing this, it is a good moment to look back at the first half of the year. Sadly, we had to say goodbye to some freshmen that had to quit MST before February. However, there is still a big group left that is working very hard to get their BSA. The second-year students have chosen their specialization; materials, synthesis or technology. Furthermore, a new group of master students started their master Chemistry or Life Science & Technology in February. Good luck to you all with your studies!

Looking back at the first semester, some usual educational events have taken place. We had two retake-trainings for the freshmen, for the courses General and Inorganic Chemistry and Organic Chemistry and Structure analysis. Research@ LIC has taken place, during which a lot of master students chose their mentor and bachelor students searched for a place to do their bachelor end project. Besides, it was a perfect opportunity for second-year students to orient on the possibilities with each specialization. Furthermore, the Master Committee organized an evening where PhD students talked about what it takes to do a PhD, what their considerations were to do a PhD and what it is like to do a PhD at the LIC. Something new this year are the labtours at the research groups of the LIC that we have organised. In the first semester, we went to visit Supramolecular & Biomaterials Chemistry (SBC), Catalysis and Surface Chemistry (CASC), Bio-organic Synthesis (Biosyn) and Molecular Physiology (MolPhys). At SBC, we not only saw interesting things, like a machine to make peptide chains or the zebrafish, but we also got more information on the types of chemistry that are used in their lab. The zebrafish are then used as models to do genetic research on human diseases. At CASC, we visited the labs of Irene Groot and Ludo Juurlink, which look a lot different than ‘normal’ labs. We learned about their work, how research on catalysis is done both on large and small scales and that a lot of the catalytic activity is determined by structural effects of the catalysts. We learned that Biosyn is a very broad and diverse group. Research is done on sugars, for example in glycobiology, but also immunology and biopolymers are fields in which they do research. During the tour at MolPhys, it was shown that it is a group where they do both chemical and biological research. They not only synthesize their inhibitors or other molecules, but they also test them using a variety of biological assays.

four labtours left. We will visit the astronomy laboratory, because, maybe unexpectedly, a lot of chemistry is done in their lab. Furthermore, we will go on tours at Biophysical Organic Chemistry (BPOC), Metals in Catalysis, Biomimetics & Inorganic Materials (MCBIM) and Theoretical Chemistry.

The curriculum of the bachelor has not changed much this year. One change is that the course Statistical Thermodynamics now includes some spectroscopy, which will no longer be given in the program of the master Chemistry.

As a result, a new core course will be added to the Energy and Sustainability track of the master Chemistry. I am very curious what the bachelor students will think of the spectroscopy part! This year, a major change has taken place in the virtual environment. The courses of the bachelor program have been moved from Blackboard to the pilot version of Brightspace of Leiden University. They are continuously working very hard to optimize this version, so that the rest of the university can also use Brightspace next year. If you have any improvement points, let me know and I will pass them through!

I would like to end this piece by saying that the college response committees (CRCs) and the program committee (PC) have worked hard to evaluate the courses of the first semester and other program related topics. Sometimes these are large subjects, but it is also about the minor things. If you have anything that you would like them to discuss, let them know or come by at the board room to discuss it with me!

Danique van Workum h.t. commissioner of education of the Chemisch Dispuut Leiden

The labtours have proved to be a great way to orient yourself on the different possibilities of doing research at the LIC. Students are able to compare the groups based on the kind of laboratories they work in, the fields and the subjects.

Furthermore, it gives them more insight in where they could do their research projects before they choose the synthesis or materials major. At the point of writing, we still have

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Photo by Lotte Vijverberg