Thursday, December 18, 2014

Some Unusual, Non-UV Photochemistry

Recent articles have highlighted a couple of unusual photochemical phenomena in living animals. While your thoughts might be that the photochemistry is UV-induced, neither one does in fact depend on UV radiation.

The first was a report from a few weeks ago (Original article ($) - C & E News coverage (open access)) regarding humans that can see near-infrared (NIR) light. The researchers found that what was occurring was 2-photon absorption, a phenomenon I've discussed before (1 and 2), where 2 NIR photons, each with half the energy needed to cause a photochemical reaction, both activate the same molecule at the same time (or more accurately, within an acceptable time window). I'm not sure of the practical applications of this and I don't think I'm enabled to see NIR (I've been deep in mines with any lights on and the blackness is incredible. I never had any hints of NIR coming off my companions), but this is still pretty intriguing. I'm sure the military is already looking into applications.

Meanwhile back in the realm of the visible light, such light is usually thought of as being pretty innocuous, at least at the fluxes we experience in our normal lives. But it turns out that certain insects are susceptible to damage by blue light (open access article). These include fruitflies, mosquitoes and flour beetles. And this is not the result of exposing the critters to some souped-up light bulb that burns out 100x the normal amount of visible light. No, this was run with with fluxes that are the equivalent to those found outside the researchers lab in Japan.

Further, the researchers found that the wavelengths for maximum lethality varied with species. Maybe this is surprising for biological systems (or maybe not), but I've made the point repeatedly on this blog and in presentations that polymer degradation rates are wavelength dependent and show a peak at a unique wavelength. So this is yet another case of us duplicating nature (even if we didn't know it at the time).

I can't help but think that this might be a good part of the reason mosquitoes are never active in bright light, preferring to come out and attack in the deep woods during the day or anywhere else at night. I don't think the kill rate with blue light is fast enough to make this discovery into an effective alternative to DEET, but I know of one local organization with a $17 millions budget that should look into this for dealing with the critters here in the Twin Cities.


Previous Years

December 18, 2013 - Nitrile Gloves Are Not The Universal Glove!

December 18, 2009 - Some subtle, subtle surfaces

Tuesday, December 16, 2014

About that Night I Spent in Jail...

Ah yes, Christmas break in 1983. I remember it well. But the story starts well before that.

Some 17,000 years ago when the glaciers retreated from Minnesota for good, they had scrapped the Canadian Shield pretty thoroughly, leaving a tremendous number of lakes in the Northeastern part of Minnesota and also the Southwestern parts of Ontario. The Ojibway discovered that the area was fabulous for canoeing. Since the distances between lakes were short it was easy to carry canoes and such between them, allowing for longer trips to be made. European explorers took advantage of the same routes, as did the fur trappers that followed. While most people think that the history of western civilization in North America in the 1600's was mostly along the coasts, there were in fact trappers and others in this area some 2000 miles away from any coast. In pursuit of beaver pelts, they would travel up the St. Lawrence river, through the Great Lakes to an outpost now called Grand Portage, and then head inland via the some of the lakes I just described. The most common route went towards Lake of the Woods and this route is in fact what now forms the eastern portion Minnesota-Canadian border. [*]

Civilization never made too strong an entry into the area and so in 1978, the Boundary Waters Canoe Area Wilderness Act became law which over the course of the next few years increasingly outlawed motors in the area, known as the BWCA for short. Boats were first to be outlawed while snowmobiles could continue to operate through 1983. The locals were plenty upset about having their motorized access taken from them, although over the last decades, things have gotten better. Ely has grown and embraced the numerous tourists that come in every summer and in the other seasons as well.

In my youth, I was active in the Boy Scouts and would go wilderness camping as much as possible. Since the Boundary Waters was about 5 hours from home, my brothers and friends would go there often. Mostly in September. Due to the University of Minnesota not starting until the last week of September, we could quite our summer jobs and go canoe for a week or 10 days. Since it was after Labor day, the area was practically abandoned and best of all - no mosquitoes!

During our trip in the fall of 1983, I was with my friend Eric on Lake Kekekabic. He suggested that we ditch the canoes and walk up the hills on the south shore of the lake to see how progress was going on the new Kekekabic hiking trail. We did this and by sure luck stumbled up the Kekekabic ranger cabin. It was empty and unlocked, but that got the wheels turning...We marked the spot on our maps and began plotting. A group of us had been wanting to go camping in the winter in the Boundary Waters, so we saw this a great opportunity. The cabin was about a 1-1/2 day trip from the nearest road end, so we figured we could ski in, spend a few days at the cabin and ski back out.

So on Boxing Day, 1983, me, two of my brothers (Mark and Paul) and 3 friends (Mike, Eric and Bill) set off for a 6-day trip, planning to come back out on New Year's Eve. We had all done winter camping before but only for short trips or 2 or 3 days. This was a much bigger undertaking. The map below shows our intended route: put in at Moose Lake, work our way over the portages to Knife Lake and then down to Kekekabic. One bonus of this route was that we could stop in to see "Knife Lake Dorothy", someone we had never met but we knew of her legend. She had run a resort on Knife Lake for decades. When the BWCA was formed, her cabin was "grandmothered" in and she was allowed to stay put until her death. (The Wikipedia article shows how much authorities kept trying to push her out, but she fought on and never conceded.) She was famous as the root beer lady, selling homemade root beer to canoeists in the summer. So we stopped by on the way out, sharing some ice cream with her that we had brought on the trip. (Yes, it was cold enough that winter to keep ice cream frozen.) She told us she wasn't overly concerned that snowmobile access ended later that week. She had lived there so long that she really didn't really rely too much on people from Ely providing supplied via snowmobile. And besides, she had a battery-powered 2-way radio if she ever got into real trouble.

We said goodby, headed on to the ranger cabin, and moved in. We got the woodburning stove going and got comfy even if the lack of electricity made it pretty dark. Breaking trail through waist-deep snow on the portages and dealing with slush on the lakes had made the trip to the cabin take the all of 3 days, so we were happy for some creature comforts. Since the trail was already broken, we figured we could make it back to the car in 2 days so we planned to break camp on the 30th. That morning, we fired up water on the camping stove for making a big batch of oatmeal. Unfortunately, in the poor light and somewhat cramped conditions, I knocked the water pot off the stove and onto the leg of Mike. Mike was only wearing his long underwear at the time...

Time to get technical and bring plastics into the discussion. Polypropylene was used back in 1983 and is stilled used to make terrific long underwear for active lifestyles as it doesn't absorb water (unlike cotton). It's also is good and insulative. If you are winter camping, that is a good thing, except when you have a couple of quarts of boiling hot water on one side and human flesh on the other. Mike got the underwear off ASAP but he had already gotten blisters and was in a good deal of pain.

After about an hour or so, we realized that Mike would have had a difficult time skiing out, so we decided Mark, Eric and Bill would ski back to Dorothy's and use her radio so that we could get Mike out on a snowmobile. I stayed behind with Mike and my brother Paul. Within a surprisingly short period, the absolute silence of the wilderness was spoiled by the sound of snowmobiles. The group had made it to Dorothy's and as luck would have it, 2 forest rangers were there talking with Dorothy and stocking her up with supplies. They took our well broken trail and got to the ranger cabin in a snap. But they also looked at Mike's leg and realized that in the rough terrain over the portages, he was not going to be well off so they made the decision to fly him out. They called in a Forest Service ski plane from Ely which arrive in a short time. The plane had room for 3 passengers, so Paul and I hopped on as well.

We got to Ely and Mike went off to the clinic for treatment. And that is when we realized we had a problem. The other three people weren't going to be coming out until tomorrow and yet Mike, Paul and I needed a place to stay that night. Ely in 1983 was not setup for overnight guests, particularly in late December. There was no room at the inn as there was no inn open for business. Afterall, who would want to stay in a motel in Ely in late December? The car was 20 miles away and even if we got there, we didn't have the keys (they other guys did). And so they put us up in the only spot they could - the jail.

The jail had 4 cells each with one bed. I still remember this horrible revulsive feeling while being shown my cell by the officer. They didn't lock the doors, but still just that feeling from seeing the bars and the toilet and the bed...I hope I never feel it again.

The next day, Mark, Eric and Bill came out off the wilderness and bailed us out picked us up. They had had a terrible last day coming out because that day, December 31st, was not only the last day that snowmobiles were ever allowed into the BWCA, but it was also the opening day for lake trout fishing, and so everyone was taking advantage of the situation. They were all heading in while our group was trying to head out.

The trip home was thankfully uneventful. Mike was ok as the burns were limited to 2nd degree and just required regular cleaning and topical antibiotics. I've seen him since and he jokes about getting into hot water fights. I still feel bad about my flying elbow causing so many problems for all of us. I've not been back to the "scene of the crime" since, but my brother Mark has. The cabin is now padlocked and there is a "No Trespassing" sign.

No surprise there. No surprise at all.



[*] The western portion of the border is a different story. The original border was based on a faulty map (it's not the first time that's happened) that showed the Mississippi river starting up in Canada when in fact it starts quite a bit further south. The border was supposed to go along the voyageurs route and then go due west from the northwestern corner of Lake of the Woods until it hit the Mississippi. The error was soon discovered and so they changed the border by drop south from that same corner of the lake to the 48th parallel, and then proceeded west to the Pacific. As a result, Minnesota is the northernmost state in the lower 48. Also as a result, there is part of the state that you cannot access by land except by going through Canada.


Previous Years

December 16, 2103 - What does EPDM stand for?

December 16, 2101 - The Real Danger in Polycarbonate (it's not BPA!) and a Solution for it

December 16, 2100 - PLA that acts like ABS

Friday, December 12, 2014

Bette Midler: "She doesn't let plastic in her house"

Bette Midler was making some outlandish statements recently (it's not as if that is news), and as you might expect, plastics got in the crossfire:
"She doesn’t let plastic in her house."
That's pretty amazing. I wonder what strange materials she has in her bathroom. Start with the toilet seat. While most are plastic, wood ones are available. Having sat on bare wood toilets on more than one camping trip, I think we can safely assume that she would not subject her derriere (or the derriere of houseguests) to splinters that could be challenging to removed. But the wood can't be painted, since the paint has plastic in it. It can't have a urethane or acrylic coating either for the same reason. Shellac or another biobased coating would be a possibility. Maybe she has metal toilets with no seats such as in prisons?
I've never used such a facility (not even on that one night I spent in the Ely, MN jail [*]) but I can't imagine it would be...er,...fun.

No Bette, there is plenty of plastic in your house and you let in all kinds of it whether you realize it or not.



[*] There's a long story behind that night. It involved no illegal activity and the cell door wasn't even locked. But that's another story for another time. And come to think of it, there is a plastics angle to it. Some maybe next week...

Previous Years

December 12, 2013 - Some Goofy Thoughts on Plastic Bags Being Seized

December 12, 2011 - The Future is Clear

Wednesday, December 03, 2014

Glove choice - it does matter

I missed this over the Thanksgiving week, so I'm assuming others did too. I've been adamant over the years (1, 2 and 3) about not just grabbing the nitrile gloves because they are readily available and because of their resistance to a broad range of chemicals. That range is broad, but not broad enough. Since different polymers and rubbers are soluble (or swellable) in different solvents, you need to be prepared to use different gloves in different situations.

Jyllian Kemsley in the C & ENew Safety Zone blog reposted this photo showing what can happen with the wrong gloves are worn:
"The organic solvent dichloromethane carried 3,4-ethylenedioxypyrrole through this researcher’s nitrile gloves. The compound polymerized onto the person’s fingers, forming poly-3,4-ethylenedioxypyrrole, a blue-black conductive polymer of unknown toxicity."
(The large number of conjugated double bonds absorb the short wavelengths and give the polymer its blue/black color, typical of many conductive polymers.)

Before you glove up, either refer to the MSDS (yes, they really do have useful information at times like this) or any of the manufacturer's compatibility charts. This page has a link to most of the manufacturers (scroll down to find them). There is no excuse for these types of images to ever occur (although it is going into my archive, since I'm sure I'll be repeating this warning in future. Sadly.)

Previous Years

December 3, 2013 - Dow Chemical to Drop the Chemical, in both Word and Deed

December 3, 2012 - The Return of the "Perfect Polymer"

December 3, 2010 - Reviewing a Paper - Round 2

December 3, 2010 - Bridgestone Cutting Rubber Usage

Tuesday, December 02, 2014

Post-Thanksgiving Hangover

It was quite a Thanksgiving weekend for me, so I'm behind on a lot of things. Consequently, today's post is pretty simple and quick to get out.

  • The British website Sciencecraft published a Q & A with me on Friday. Since I'm sure many Americans were out shopping for Black Friday specials and dozing off after eating turkey sandwiches, you might have missed it. I was asked a lot of wide-ranging questions and gave back even more wide-ranging answers, so I'm sure someone will take issue with something I said.
  • It's been about 6 months since we last were told that peer reviewers are being overworked and so we're about due for another opinion piece on the matter. Sure enough, here's the latest of the same-old-screes, in Nature of all places. As I've said in the past, you could use industrial researchers, since they outnumber academic researchers by 20-to-1 or some ridiculous number and they are largely untapped. Maybe it's time for a letter to the editor.
  • I will need to dig further into this one as it looks interesting, but the Daily Mail has an article relating pasta and polymers. Not the standard comparison of spaghetti and linear polymers as you might expect, but a new pasta shape, anelloni and polymer rings. While polymeric rings are nothing new, the modeling performed for this work shows that extremely large rings become entangled and glassy. The article is pretty poorly written so I'm not going to read too much more into it until I can track down the original research report.


Previous Years

December 2, 2011 - The Teacher Can Make All the Difference

December 2, 2010 - Think It's Obvious? Prove It.

December 2, 2011 - Adieu Hercules

Wednesday, November 26, 2014

Plastics and Thanksgiving

Tomorrow is Thanksgiving Day here in the US and so it will be pretty quiet on the interwebs. Friday won't be much better as many people have that day off too. Last year at this time I blogged about the netting around turkeys and how much underappreciated that product is. If you didn't read it last year, I would suggest you take a look.

This year, I'll keep it short and just mention that the American Chemical Council's blog has a great overview of how polyurethane is used in creating the giant balloons used in the Macy's Thanksgiving Day parade. (As well as a few other examples of how polyurethanes make the day more enjoyable.) It's worth a look. And making those balloons would be one cool job to have.


Previous Years

November 26, 2012 - Fantasy Images of the Great Garbage Patch