This post is just going to be a really long recap of the science topics we covered during our week in Uppsala. This portion of the course is an extension of our natural science-oriented excursions in Mora, by bringing chemistry topics into focus, as well as giving us an overview of the history of science in Sweden from about the 1500s. Each day featured a scientific history lecture, followed by a presentation by a researcher, and then a few of our own brief presentations on elements that we chose during Spring Break. The week also featured presentations by researchers and a Ph.D. student, from both Uppsala University and SLU and was rounded off by a brief report on elements we chose for presentations. I’m going to focus on talking about the researchers we met. If you just want a general impression of the science during the week, you are welcome to skip to the final paragraph.
Andrew presented on Monday. Andrew is a researcher from the University of Uppsala who attended Gustavus. His work involves Type 1 diabetes, so naturally he began his presentation by talking about the biochemistry “behind” diabetes as context for how researchers are trying to cure it or reduce the amount of treatment required to combat its symptoms. Andrew is not currently working on a cure, but he is working on a treatment called “islet transplantation.” The goal of islet transportation is to reduce the dependence that Type 1 diabetes sufferers have on insulin shots, as islets (obtained from pancreases) produce insulin. I’ll go over the process as Andrew explained it to us, and then I’ll talk a bit about the results of islet transplantation.
The original procedure to obtain islets from pancreases was developed in 1965, but there have been a lot of developments since 1991 which have improved and modernized the treatment. First, a pancreas taken from a healthy organ donor must be procured. It can’t be too fatty or lean and must match the blood type of the recipient. The pancreas is dissected and pumped with an enzyme which starts to break down the pancreas, but the break-down is continued by putting the pancreas in a “shaker” that contains marbles. After the pancreas is sufficiently dissolved, the resulting liquid is put into conicals, which are centrifuged. The desired islets will appear in the bottom of the conical. Each of the islet clumps found in the conicals are combined and stored. Obviously, there are more technical aspects to the procedure, but I think that’s a pretty good summary. Anyway, the islets are implanted on the liver and then vascularized. That part is essential, because the islets will not produce insulin unless supplied with blood. The liver is chosen for the implant, because thus far it has simply proven to be the best place, and, in the words of Andrew, the liver is a “very robust organ.”
If you guessed this procedure sounds expensive, you’d be right. Currently, a proper pancreas goes for around $30,000 while the isolation procedure costs about $12,000; however, this procedure has proven to be less risky than a pancreas transplant, which is currently the most common procedure. And, in five years, an average of 10% of the islet transplant patients become insulin independent—that is, they don’t have to take separate insulin shots. I’d say this research looks very promising.
Daniel Lundberg, our host for the week in Uppsala, presented on Tuesday. Daniel graduated from Gustavus in the 90s, and went on to obtain his Ph.D. in Chemistry. In addition to organizing our week in Uppsala, Daniel functioned as a tour guide in both Stockholm and Uppsala. He focused on lecturing us on the history of science in Sweden, but his presentation involved his work with his favorite molecule, DMPU, and coordination chemistry.
So what is coordination chemistry, exactly? Well, according to Daniel, it’s “chemistry of a different kind.” But coordination chemistry is the study of the structure of molecules and how they bond together. To do this, Daniel spends a lot of time using an X-Ray Crystallography machine. In short, this machine works by “shooting” x-rays at a rotating crystal, causing the x-rays to diffract and display a pattern on a special screen behind the molecule. A researcher like Daniel can then look at the data that this machine generates in order to build a diagram of the crystal structure of the molecule. The data is a two-dimensional picture which is transformed into a three-dimensional structure using mathematics. By examining the structure of molecules, scientists can study how they might behave when bonding with other molecules. This isn’t the only method used to determine crystal structures, and there are three others that Daniel talked about which can even be combined to get a more accurate crystal diagram.
One method of determining how a molecule might bond is by looking at a particular coordination number. A coordination number is the number of ions which can fit around an atom, or in other words, the number of ligands (“arms”) around an atom. This number ranges from 2-12, and some common numbers of ligands are 4, 6, 8, and 9. The coordination number can tell a researcher how stable a particular atom might be for bonding. For example, 4 or 6 and 8 or 9 are stable. The first number of each pair refers to a crystalline (or solid) state, and the second number refers to the same substance in solution. Examples of unstable coordination numbers are 5 or 7.
When talking about ionic radius, Daniel focused on telling us about how it’s used to determine the radius of particular atoms. In order to do that, a researcher pairs the desired atom with many different ones and repeatedly measures the ionic radius between the pair. By doing this repeatedly with other elements, the numbers can be plugged in to see what works for the sums of all the bond distances.
I suppose Daniel loves DMPU probably because it was interesting enough to be the subject of his Ph.D. thesis. He wanted to figure out the geometry of the crystal structure and coordination number of DMPU, which is a replacement solvent for the more toxic HMPA. HMPA is used in synthesizing organic compounds, and DMPUs lower coordination number makes it advantageous. But Daniel’s research also involved working on coordination chemistry with cadmium, zinc, iron, and lanthanoids (which is a group used extensively in cell phones, and their coordinating properties are what make them work so well). Daniel figured out that the elements Lu, Yt, and Et all had nearly identical coordination numbers (6 for solid, 7 for solution, except for Lu which was 6 for both). He concluded that the coordination number may be different for solutions and solids, and that one must combine crystallography techniques in order to get the best results. His paper also determined that the lanthanoid series was suitable for further coordination studies. I’ll talk more about Daniel’s role in the history lectures after I’ve talked about all the speakers.
On Wednesday, Harald presented his research on microorganisms and herbicide use on railways. Harald doesn’t have a connection to Gustavus, but he has presented to students on the Semester in Sweden trip before and is a colleague of Daniel’s at SLU. Side note: Harald has an awesome moustache. Anyway, he likes to focus on microbiology and studied herbicides simply because his graduate school adviser had a project and funding available to do it. Harald thought, “Why not?” and went ahead with it. He really seems to enjoy his work, though. He gets to do a lot of press conferences and work with Sweden’s railway management agency.
When Harald first started discussing his work, I wasn’t quite sure why he—or anyone else really—cared much for the little ecosystem that exists in the soil underneath railroad tracks. According to Harald, the microbes in the soil were not very active and dying off. The problem is that railroad companies don’t like to have plants on the tracks, or even to the sides, so railroad tracks are often sprayed with herbicides. The problem is threefold. One, since there is no plant matter which falls into the soil and decays, microbes don’t have any nutrients to grow. Secondly, herbicides can be transported in the groundwater and pollute water supplies and kill other plans unintentionally. Lastly, railroad workers have a historically higher rate of certain cancers, and some studies have attributed this to herbicide use. Harald went over a history of herbicide use on Swedish railways, noting each herbicide’s effectiveness and problems. Another issue that Harald touched on was creosote use. Creosote is a preservative used on wooden railroad sleepers which can seep into the ground. Eventually, though, creosote eventually becomes “not so bad,” according to Harald.
Anyway, an important relationship to note is that particular herbicides can be eaten (or “degraded”) very effectively by the microbes in the soil under the railroad tracks. Harald is trying different herbicides out, to see which ones offer the best combination of leeching and degradation characteristics. There are two types of growth associated with the microbes that Harald works with, those being co-metabolic and metabolic. Co-metabolic degradation means that, at first, a particular herbicide will be degraded very quickly at first, but then the degradation process will slow down significantly over time. The metabolic process means that growth of microbe populations is associated with degradation (i.e. the herbicide is used as food for the microbes). As the microbes grow, metabolic degradation means that an herbicide will be degraded very quickly. If a given patch of soil initially has very few microbes, metabolic degradation is much quicker; however, if the patch already has a lot of microbes, there is little difference between the two types of degradation. As far as leeching goes, the desired characteristic depends entirely on how quickly an herbicide degrades, and how mobile it is (how much it leeches). If a particular herbicide takes a long time to degrade (long half-life), you don’t want it to be very mobile. Conversely, if an herbicide degrades quickly (has a short half-life), it’s okay if it is really mobile. Harald did once find an herbicide which had the desired combination of leeching/mobility and degradation characteristics, but unfortunately it wasn’t actually very good at killing plants. As a final note, the leeching potential of a given herbicide expectedly depends on how much of it you use.
We know now that the health of microbiological ecosystems is very important for the degradation of herbicides, but there are still some issues that arise, even if Harald does find the perfect herbicide. The first issue arises from the way in which herbicides are applied. With repeated spraying, a given herbicide will degrade faster and faster every season. This could be problematic, especially if such herbicides are used by farmers, as eventually herbicides will not last long enough to work, requiring ever-larger doses which, as I mentioned previously, would increase the leeching potential of the herbicide and potentially “outpace” the degradation process. This means that the railroads would have the same herbicide pollution problem as before, potentially causing groundwater contamination and health problems for workers.
Finally, on Thursday, we listened to a presentation by Julia, Daniel’s “sambo.” Perhaps you all know what that means at this point in our trip, but if it hasn’t been mentioned before or you’ve forgotten, that means that Julia and Daniel are living together but not married. Julia is currently working on a Ph.D. in analytical chemistry, and plans to apply her degree to the environmental question. Julia did not focus so much on presenting her own work, but raised awareness of environmental issues by engaging the class in calculating its carbon footprint. We collectively calculated that it would take about 7.5 earths to sustain our lifestyles! Looks like we need to make some lifestyle changes. I couldn’t find the environmental footprint calculator we used in class, but there are plenty of different ones out there which can enlighten you to your own habits. Julia also engaged in a discussion of our own habits, by having us list both our good and bad habits in order to get us thinking about simple ways we could start off with to “green” our lifestyles.
After a discussion of our own habits, we talked more about Sweden and what Sweden has done and plans to do regarding the environment. Sweden’s objectives revolve around cleaning the air, water, and soil, and to pass on an environment with most of its problem fixed to the next generation. To achieve this “generational goal,” Sweden has outlined 16 different objectives which each have benchmarks to reach by 2020. Unfortunately, most of the goals won’t be reached by 2020, but when shown the indicators for each goal (literally using arrows and smiley faces), it seemed that many situations were improving, or at least not getting any worse. A few of the goals which Sweden has outlined include improving biodiversity, protecting and restoring its ecosystems, ensuring clean groundwater and air, and reducing its climate impact.
As some of you may already be aware, Sweden has great public transportation infrastructure. Bikes are easy to ride around, and cities are concentrated enough to make them widely viable. Many people in Sweden don’t even have driver’s licenses, let alone cars. While Sweden’s public transportation system is great, it also discourages automobile use by taxing the heck out of gasoline. Gasoline has a few different types of taxes. Two examples are an emissions tax and just a simple carbon fuel tax. Many cities are now using biogas for its bus systems, which reduce emissions. And about 90% of Sweden’s heating energy comes from renewable sources. Enough waste is recycled such that garbage trucks only circulate every two or three weeks in many neighborhoods. However, there are questions raised regularly about the true efficiency of Sweden’s recycling program, which you can read about in various articles on the web. Anyway, about half of Sweden’s total energy (cars included) comes from renewable sources. So Sweden is certainly a country that is on its way to becoming carbon-neutral. Sweden ambitiously set its emission-reduction goal much higher than the EU after signing the Kyoto Protocol, an agreement which created legally-binding emission-reduction targets in 1997 (not entering into force until 2005). I suppose that in the environmental situation, its best to overreach than settle. In fact, Sweden hopes to be completely carbon-neutral by 2050, and that’s after essentially eliminating fossil fuels from its vehicle fleet by 2030. So with those stats, I’ll leave it be. Appropriate for Earth Day! I’ll wrap up this post by briefly talking about Swedish scientists and scientific history.
Time to wrap up this really long post. Each day Daniel took us through a bit of Swedish scientific history. I’m just going to make some general comments about that portion, because the thing that I took most from it wasn’t the facts, but the general sense that Sweden has been incredibly productive and important to the sciences. Not just for the well-known Nobel Foundation and Nobel Prize, but for the contributions that Swedish scientists have made, especially to chemistry. Sweden “owns” a lot of big names, particularly Scheele, Berzelius, Linnaeus, and Celsius. I don’t need to go into what these individuals have done, but I’m sure you recognize a couple of those. In fact, all four of the individuals I just named worked at Uppsala University at one point. I was incredibly impressed by the importance of this institution to the sciences. As well, Anders Ångström, a prominent physicist, was educated at Uppsala. Numerous elements were discovered in the old chemistry building on campus, and, as a science major, it was really humbling just to be walking in the same space where all these discoveries happened. Daniel kept reiterating that all these great scientists are portrayed when they’re older, and that they made all these incredible discoveries at a young age. It was an obvious hint that young people really do important work and that we shouldn’t get discouraged by thinking our intellectual prime is far off—it really puts things into perspective and makes all these great scientists seem less “intimidating” figures. In a weird way, it’s comforting. But anyway, that’s all I have to say about our science portion. I realize it was a long post, but I felt like the researchers were a highlight and deserved attention. Thanks to Daniel for a great week of learning!
-Will