Epidemiology circles back to sewage

Epidemiology, the statistical study of population health instead of a single person's health, has taken population-wide sampling to a new level—underground.

Instead of collecting data on individuals representing a subset of the population and then averaging it, the researchers let an existing piece of infrastructure do the averaging for them. This also made sure they were actually getting properly anonymized data from every single resident of the study area—because the area of study was "everybody connected to the sewer", and everybody who has one, uses the toilet.

What they were testing, specifically, was the percentage of people who took their medicine, by having the entire city collectively pee in a cup.

Opening my eyes

I was on a work trip and sitting in the lunchroom at a client site, chatting with the operators there. It was a friendly group, and we got to know each other reasonably well in our lunchtime conversations. I and one of the locals were talking about running and race training, being both runners. Another of the operators mentioned that he occasionally ran a mile at the track, and was asking about training for a 5k race, three times farther than he had run before.

Because he and I both find running more than a mile or so on the track unutterably boring (I think he hadn't run more than a mile on the track partly because he was bored, not because he was too tired to continue) I suggested that he run on the street, through the neighbourhood where he lived, so at least the scenery was a bit different. I frequently use google maps' walking directions tool to plot out a route of the distance I want to run when I'm not in the mood for an out-and-back straight line run, especially in an unfamiliar city.

He laughed and said he couldn't do that. Because he predicted a response to him being out running along the sidewalk: "Honey, call the cops! There's a black man running!" And the rest of the group laughed, because they knew it was true.

It had never in my life occurred to me to even think that somebody might call the police on me while I was out minding my own business on a training run.

White privilege: yeah, I have it.

Don't look under the hard hat

One morning, my co-worker picked up a hard hat off a chair in the site office trailer. This would normally have been a perfectly normal thing but on this day, there was a tarantula hiding in the cozy, dark, and air-conditioned cool place it had found overnight.

After a bit of surprised dancing, the tarantula was left alone. They're pretty mellow and not dangerous, and besides, we had to get to work outside in the hot.

A while later when we went back into the office, the tarantula was on the ceiling. With a hard hat minus its harness, we got the tarantula into the hard hat to put it outside. After, of course, my co-worker asked for a photo of himself with the tarantula.

The tarantulas, as scary as they look, weren't the scary ones in that area. It was the sort of place where you banged your boots around a few times before putting them on in the morning to make sure nothing had taken refuge inside.

I never had anything inside my boots, but one morning I did wake up to a scorpion on my pants.

Thawing sweets

Here's a thing that I didn't even know was a thing to wonder about:

You know the sugar maple, which produces the raw material for maple syrup by dripping sap into a bucket in the spring. Well, it turns out that it's not only a case of the sugar maple's sap being particularly sweet and thus well suited for this use. The sugar maple, along with a couple of other trees, are the only ones which drip their sap out in a way that can be usefully collected, and it is also particularly sweet.

The question, or rather questions, are:

Why only a few types of tree?

Why does this only happen during spring thaw, in certain temperature conditions?

How does this happen at all?

Some mathematicians from SFU on the west coast decided to calculate this east coast phenomenon.

Chemophobia

I've been busy lately so I haven't had time to put together any good posts. In the interim, here's some interesting reading. The first sentence describes me perfectly, but then I'm one of the group named in it as well: "It’s the number one pet peeve of just about every chemical professional I talk to: why is ‘chemical’ such a dirty word in the minds of so many people?"

Even people who have some interest in chemistry can fall prey to this. I was talking to a friend (who does have an interest in chemistry) recently and this came up, and he pulled out a few of the classics about synthesized things not being tested "enough" (even though it's been my experience that for many chemophobes there is never a level that will be "enough") using "unnatural" or "chemical" as a loose synonym for dangerous—acknowledging immediately when I pointed out that there are plenty of natural poisons, because he does know more than a little about chemistry, BUT...

It's easier to argue with strangers about this, than with friends; at least I find it so. It sucks when friends hit your pet peeves, and it's easier to walk away from strangers who do the same.

Not chemistry

Ok, this isn't chemistry, or engineering, but I think it's pretty cool.

Archaeologists found king Richard III, for real. The location and battle wounds and twisted spine were excellent clues, but the DNA test comparing the skeleton to two people descended from his sister confirmed it.

DNA testing is chemistry-related, right? Ok, this post is chemistry related after all :-)

Natural distillation

I was out snowshoeing with a friend not long ago, and ate some snow because I was thirsty. My friend made a comment about the "distilled water" taste of snow, and I suddenly realized something that, really, I've known all along—snow effectively is distilled water.

Water distillation involves vaporizing impure water, then condensing the water vapour back to a liquid. In the case of snow, water vapour in the air freezes directly into snowflake form, making them pure—distilled—water.

Raindrops, on the other hand, while they also condense out of the water vapour in the air, absorb other vapours into the drop. There are some things that absorb more easily than others, SO₂ being one of the well known pollutant related compounds that absorbs easily into water, and which makes acid rain. It's a little harder (but not impossible) to dissolve other stuff into solids.

Bouncing liquids

Never mind hydrophobic, how about "omniphobic"?

A new material—or rather, a new shape of an existing material—has been made that rejects nearly every liquid thrown at it, both oils and waters, both acids and bases. The material is a plastic, one with slightly lower surface energy than the famous PTFE (Teflon), so it has very little stick to it to begin with.

In order to make the liquids not only not stick but actually bounce right off, they changed the shape at a microscopic level so it wasn't a smooth flat surface, but a textured surface that was mostly air:

Posted with permission from J. Am. Chem. Soc., 2013, 135 (2), pp 578–581. Copyright 2012 American Chemical Society.

Inspired by: bacteria

Here's another one where nature meets engineering on a microscopic scale: tiny submarines small enough to swim through your blood vessels.

Oops, wrong link.

The submarines I'm actually talking about won't carry people, but once built they could be made to carry small doses of medicine, and directed to swim to a specific spot in your body.

The reason this merits a mention in the "nature meets engineering" category is that down at the 10\(\mu\)m scale (which is to say, 100 of these lined up end to end would only reach 1mm long) you can't just build a tiny motor and propeller and expect to have the submarine go anywhere, because at that scale, the physics of it just doesn't work. Instead, what they looked at was how creatures that are actually that small get around.

Folded Solar

Solar electrical is pretty exciting right now, I must say. After my previous post on some of the cool stuff coming up in photovoltaics I let it slide for a while and chased other cool news, but this new thing from late December really caught my attention.

I mean, solar panel stickers? Which you can apply to fabric or paper, bend them, and have them still work?

The researchers say that this technique isn't only good for solar panels but also possibly for electronic circuits, transistors, and even LCDs as well. Maybe you really could have a solar powered, electronically active jacket, including flexible display, one day. Imagine, a self-powered jacket that could show you a map of where you are, among other things.

They tested the solar panels to a bend radius of 7mm without any damage. I don't know if it would handle a crease (if on paper) very well, or crumpled-clothes type bends. From the paper, it doesn't look like they tested its bending abilities to failure.