Science Advocacy
Science Advocacy
Welcome to “chemicals and society” a new feature at UYBFS where we highlight the current understanding of the biologic effects and safety of some of the most common chemicals in today’s society.
What is vitamin A and how are people exposed to it?
“Vitamin A” is technically a group of very similar chemicals. The main forms in the body are retinal, retinol, retinyl esters, and retinoic acid. Vitamin A is required for normal development and function in all vertebrates (animals with a backbone) and some non-vertebrates (like worms and bugs). Since animals can’t make vitamin A from scratch, they require dietary sources – either from plants containing carotenes (you’ve probably heard of beta-carotene, but did you know there were alpha and gamma forms too?) or by eating other animals who had already produced vitamin A from a plant source. several forms of vitamin A (tretinoin, isotretinoin, and alitretinoin) are also FDA-approved drugs, used to treat severe acne and some rare skin cancers.
Welcome to “chemicals and society” a new feature at UYBFS where we highlight the current understanding of the biologic effects and safety of some of the most common chemicals in today’s society.
What is Nicotine and how are people exposed to it?
Nicotine is an alkaloid produced naturally by a number of plants in the night shade family, most notably the tobacco plant. People are mainly exposed to nicotine by smoking (cigarettes, cigars, pipes, smokeless tobacco), but also via vaping or e-cigarettes. Some people may be exposed to nicotine or related chemicals when using them as insecticides on crops.
What does Nicotine do?
Plants produce nicotine as an insecticide to keep insects from eating their leaves. Nicotine binds to nicotinic acetylcholine receptors (nAChRs) in the central nervous systems of insects, causing paralysis and death. In mammals, the nAChR receptor subtypes are different, and as a consequence, nicotine binds more weakly and stimulates the nervous system, causing the characteristic addictive “high” that people seek out by smoking.
Nicotine itself (sold as nicotine sulfate) can be used as a pesticide, though it is not currently sold in the U.S. Nicotine derivatives (known as neonicotinoids) are widely used as insecticides across the world. They have come under quite a bit of scrutiny lately because these insecticides are very good at killing bees – and could be one of the contributors to colony collapse disorder.
Over a year ago, I attended a seminar on the current treatments of opioid addiction. The talk was given by a physician at University of Arkansas for Medical Sciences (UAMS) in Little Rock, who has been treating opioid addicts for over 25 years at the methadone clinic. Paradoxically, opioid addiction is treated with other opioids such as naltrexone, methadone, and buprenorphine. The speaker mentioned that throughout his entire career, he has never had a patient who fully recovered from opioid addiction; however, he has had many patients who lead a fulfilling and successful life on methadone.
In 2015, prescription drugs killed more than 33,000 Americans, and half of those deaths involved a prescription opioid,1 and early August of this year, our president of the United States proclaimed that he considered the opioid epidemic a “national crisis.” (Although, as of this writing the opioid epidemic has not been formally declared a national crisis.) So, how did the problem of opioid addiction become an epidemic?Continue reading…
Welcome to Ask a Scientist, where we answer questions from our readers on a wide range of scientific topics. Got a scientific question? Drop us a line.
Is pink slime dangerous and how can I avoid it? – K.B. Chico, CA
Great question! Here’s the skinny:
“Pink slime” is a pejorative term for “lean finely textured beef” (LFTB), “finely textured beef” (FTB), or boneless lean beef trimmings (BLBT). It’s added into ground beef as a filler and to reduce the fat content of the final product. To make pink slime, boneless beef trimmings (small leftover pieces of beef) are heated, centrifuged (spun around really fast to remove the fat), frozen and crushed into a paste. To disinfect it, ammonia or citric acid treatment is often used.
The term was coined by a USDA scientist by the name of Gerald Zirnstein. He didn’t like the look of the pink slime (to be fair, almost no one does), and he objected to it being classified as meat (he was overruled by his USDA superiors). Zirnstein may have had a point – this is probably stretching the definition of meat that most of us would accept. Basically, they took some fatty pieces of meat, removed most of the fat and turned what was left into a paste in the process – I guess that’s sorta meat? More like a meat puree? Whatever you call it, there is little doubt that it is made from meat, so we’ll just call it meat and move on.
Using ammonia to disinfect the LFTB has received much of the media attention, partly because it is specifically banned from use in Canada and the European Union (EU). However, Canada and the EU allow similar products which could be described as pink slime. The citric-acid treated LFTB is used in Canada and the EU allows something called “de-sinewed meat” or “red meat paste.” These all sound gross.
Ridiculous question from the internet: Can a human get a dog pregnant?
Source of said ridiculous question: Google Autofill*
Science’s answer: Oh my God No! We are hoping this is just curiosity and nothing… more. Seriously, though – most species can not mate successfully with other species for a variety of reasons, mostly because they physically can’t, or biologically their anatomy and physiology won’t permit it. In the few cases where this is possible, the two species in question are closely related, meaning they diverged evolutionary in the relatively recent past. Here are some fun examples:
In most cases, species that can interbreed have the same number, or at least a very similar number of chromosomes. You & I, however, have 23 sets of chromosomes, while a dog has 39 (despite having fewer genes overall). From a practical chromosomal segregation standpoint, that is a dumpster fire. It just won’t work.
“Get Tinder, everyone has it!” I hear that from my peers too many times. “All you need to do is sit back, relax, and swipe!”
For those who don’t know: Tinder is a location-based social dating app that has over 50 million users worldwide1 and it works through a simple principle: look at a person’s pictures and swipe right if you’re interested, or swipe left if you’re not. On Tinder, everyone can have virtual autonomy and the opportunity to select their potential dating mates based on their pictures.
As a biologist, the big questions I have are: What do evolutionary and neurobiological theories tell us about the most common parts of the online dating process? Although culture and heritage highly influence the perception of beauty and the visual aspects of attraction, some studies suggest that our preferences may be influenced by evolutionary biology. So, let’s explore the steps from getting a match on Tinder to the actual date, and see what evolutionary and neurobiological theories can tell us about the dating process.
