Category Archives: Chemistry

The dangers of acetaminophen

Recently, This American Life did an episode on how easy it is to overdose on acetaminophen (also called paracetamol in countries outside of the US). You can listen to the entire episode in the link below:

505: Use Only as Directed

What I find interesting is why this drug is so dangerous.

In the liver, there are a group of enzymes that oxidize many of the drugs and organic substances that enter your body. In fact, there are genes for 57 various types of these enzymes. These are called Cytochrome P450s.

Whenever you see warning labels like “don’t eat grapefruit with this drug,” it is usually because of the way the liver cytochromes are processing these compounds.

So, what happens when you take acetaminophen? Most of it is processed to a non-harmful compound. However, 5% of this drug is processed by a liver cytochrome known as CYP2E1. This 5% becomes a toxic compound (NAPQI). Generally, the liver can take care of this substance through a reaction with a compound known as glutathione. However, in cases of overdose, there is not enough glutathione to convert the bad NAPQI, and it hangs out in the liver and reacts with cellular membranes. Essentially, your liver cells are slowly killed.

Noncontact Atomic Force Microscope Shows Molecular Reformation

 

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High-Resolution Images of a Molecule as it Breaks and Reforms

Using a very neat technique, scientists were able to image a chemical reaction. I would suggest taking a look at the article, especially if those stick drawings of organic chemicals always intrigued you.

What this lab has done is use an atomic force microscope (AFM) to detect atoms and forces between the bonds during a chemical reaction. The resulting images through the process are fascinating.

Exploding Capacitors

What happens when you hook a capacitor to a voltage source backwards?

Explosions!

The labs were one of my favorite parts of electrical engineering. Of course building things was fun, but some of my memories of lab were of breaking/exploding/burning things. Chemists think they have all the fun, but really, it’s the electrical engineers that have all the fun. I’ve taken many chemistry labs outside of engineering. While I enjoyed making esters and beautiful dyes, the most fun shenanigans to be had existed in the electrical engineering labs.

Often times during a lab session, this odor of burnt electronics wafts through the hallways. There are many things to destroy. Capacitors, diodes, resistors—they are all fair game in an undergraduate electronics course. I’ve also tried various food items in electronic circuits as well. Marshmallows are fairly uninteresting, but if you find a nice salty watery food like a pickle, you are in for a treat. Yes, the halls of the electrical engineering wing are always filled with the faint smell of burning.

Encountering the Aurora

“Wow,” I thought to myself, as I saw the Aurora fluttering through the sky. I grabbed my camera with my shivering hand and begin to point and click numerous times. I definitely did not succeed in taking any viable pictures on my first time viewing the magnificent aurora. I didn’t succeed the second night either…

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Upon my first time seeing the Aurora, I immediately felt this ethereal connection to previous humans who had claimed the Aurora were sky spirits. My scientific brain took over as I realized I was making a spiritual connection to a chemical reaction in the sky.

What are the Aurora?

There are actually several kinds of Aurora that we can see with the human eye. The image I posted is of the green line aurora. This type of aurora is caused by an emission by an electron moving from an excited state to a lower electronic state in an oxygen atom. There are three reactions that take place to cause this electronic emission of green light.

1) Energy transfer between N2 and O

2) Dissociative recombination of O2+ + e

3) Direct excitation of atomic oxygen by ambient energetic electrons

When the earth’s magnetic field is disrupted by solar winds, ions are displaced to the lower atmosphere in excess. This influx of added ions and electrons is what cause increased chemical reactions during the aurora.

Capturing the Aurora

The photographs I took of the aurora on my first attempt were just black dark shots of nothing. I managed to get strange faint green wisp in one of the shots, but aside from that, the pictures were really just blank.

After being directed to a website about photography, and getting encouragement to try and take decent pictures, I caved and bought a new camera. It was the cheapest camera to be found that took extended exposure photographs. Alas, after increasing the exposure and sensitivity to light, I captured the aurora.

I still have a ways to go before I take stunning and crisp pictures, but it’s certainly a step away from my previous label of stunningly bad photographer.