Chemistry – Page 2 – David Bradley

My cautionary article about the dangers of mixing cleaning fluids caught the attention of TV doctor

About a year ago, just as everyone was thinking about making their own sanitisation handwash and scrubbing groceries with bleach and soapy water at the start of the pandemic, I wrote a feature article for Chemistry World to warn people not to mix bleach and other cleaning fluids. There are serious risks of generating toxic fumes, chlorine gas, and such. The article was fairly well received, I believe.

Interesting that an episode of the BBC’s Call the Midwife (S10E05), which is set in the 1960s, Â has a sub-plot where a character foolishly mixes some cleaning products…and Doctor Turner, played by the dashing Steve McGann, dashes in to warn of the dangers as the fumes billow from the bucket. I asked him on Twitter if my article had been the inspiration…this was his reply and I quote:

Ha! David, you are our primary source for all things! :-)

Thanks Steve

Vaccination NOW

TL:DR – At the time of writing, vaccination of COVID-19 was getting underway. It is still highly recommended despite the disinformation, fake news, and conspiracy theories.

In a few month’s time, the first 10 million people will have been vaccinated against covid. Within two months, 4000 of those people will have a heart attack, 4000 will have a stroke, 10000 will be diagnosed with cancer, 14000 will die.

How many of those illnesses and deaths will be due to the vaccination? None of them.

But, the antivaxxers will start to claim some of those 4000 strokes, those 10000 cancers, those 14000 deaths as being caused by the vaccine. They will be wrong to do so. Why, because if we were to start counting 10 million people from today, none of them yet vaccinated against covid, within two months, 4000 of those people will have a heart attack, 4000 will have a stroke, 10000 will be diagnosed with cancer, 14000 will die.

If you know 100 people of all different ages and demographics, then one of them will have a heart attack within the next four years, one of them will have a stroke in that time, a couple of them will be diagnosed with cancer, and in those same four years, 2-3 will actually die. That’s the statistics. If you’re one of somebody else’s 100 friends, then you could be in any of those groups. This is the normal of life, disease, and death.

In the new-normal of the covid world, we need as many people as possible to be vaccinated to quash the spread of this new virus, otherwise there will be much bigger numbers to record in all of the above.

Drug discovery scientist Derek Lowe has much more to say on this topic having built on a twitter thread from Bob Wachter (Chair, University of California San Francisco Department of Medicine).

Of course, once we’re vaccinating millions of people, there will be some side effects and there will be some effects that arise that might be caused by the vaccine or just other random effects of the human condition. The fact is though, that the morbidity and mortality rates for covid will far outstrip any side effects of adverse reactions seen in the people who get the vaccine, this much is true from the trials of thousands of people who have been tested with the vaccine already.

The antivax movement will jump on every disease, every death gleefully proclaiming that the vaccine is to blame. But, 14000 in every ten million people would die in any random two month period before we’d even heard of covid. Now, that we have covid with us that is an extra cause of death to add to our terminal list. Vaccination will minimise those extra deaths, so that hopefully none of us will lose too many of our 100 friends to this dreadful disease.

Adverse effects of hydroxychloroquine

UPDATE: If you have been prescribed this drug for another condition, do not stop taking it without consulting your GP. Your GP will have prescribed it for a good reason and will know your medical history and undertaken a risk-benefit assessment before signing your prescription. The majority of the side-effects are rare and it is generally safe to use for the approved conditions if heart problems and other underlying possible complications and contraindications have been ruled out for you.

In case you were ever stupid enough to follow Trump’s lead you would have already injected ultraviolets in your eyeballs by now to save you from Covid and maybe bathed in Domestos or sulfuric acid or both! Anyway, his latest bullshine claim is that he’s been taking the antimalarial drug hydroxychloroquine to keep Covid at bay.

Well, for starters there is no evidence that this drug acts as a prophylactic against infection with SARS CoV-2 or indeed any pathogen other than the causative agent of otherwise drug-resistant malaria. It’s primary use is in treating lupus. There was some testing done weeks ago to see whether it might work against SARS-CoV-2, it almost certainly doesn’t, there will be actual antivirals to try and some being developed as we speak.

Either way, did anyone actually do a benefit-risk balance assessment for him or has he self-medicated on a whim? I strongly suspect that he is not taking it at all and that there is some hidden agenda. As with everything else he says bullshit or otherwise a political or financial incentive is often at the front of his frothing, festering mind.

The US Food and Drug Administration warns against taking this drug outside the clinical environment because it can cause serious and potentially lethal heart problems”. If you were thinking of taking inspiration from The Trunt listen to the FDA or maybe have a look at the huge list of post-approval adverse reactions and side-effects already reported for hydroxychloroquine:

Bone marrow failure, anemia, aplastic anemia, agranulocytosis, leukopenia, and thrombocytopenia, hemolysis in people with G-6-PD enzyme deficiency, Cardiomyopathy and fatal cardiac failure, ventricular arrhythmia, Vertigo, tinnitus, nystagmus, nerve deafness, deafness, eye irreversible retinopathy with retinal pigmentation changes (bull’s eye appearance), visual field defects, and visual disturbances, macular degeneration, corneal edema and opacity, nausea, vomiting, diarrhea, and abdominal pain, fatigue, liver failure, urticaria, angioedema, asthma, poor appetite, hypoglycemia, porphyria, weight loss, sensorimotor disorder, skeletal muscle myopathy or neuromyopathy leading to weakness and muscle wasting, failing tendon reflexes and abnormal nerve conduction, headache, dizziness, seizure, ataxia and dystonia, dyskinesia, and tremor, emotional problems, nervousness, irritability, nightmares, psychosis, suicidal thoughts, rash, pruritus, pigmentation disorders in skin and mucous membranes, alopecia, skin eruptions, toxic epidermal necrolysis, photosensitivity, psoriasis…

The complete, detailed list of ADRs and side-effects can be found here.

Handgel and hot cars

There’s some deceived wisdom doing the rounds about not leaving bottles of 60% alcohol hand sanitizer in your car when it’s hot because it could spontaneously burst into flames. There are pictures of the damage apparently caused by the hand gel burning through the dashboard.

This is not at all likely to happen at the temperatures you’re like to reach in the passenger compartment of a car. Moreover, if the interior of your car were to reach the necessary temperature for spontaneous combustion of hand sanitizer, that little bottle of gel is the least of your worries.

The flashpoint for 60% ethanol in water, may well be low (about 23 Celsius), but you need something to *ignite* the liquid, it won’t spontaneously burst into flames. Even petrol cannot spontaneously combust until it’s above 280 Celsius, hence the spark plugs to ignite it (an electric spark will peak at about 4500 Celsius).

However, the handgel may well get very hot and opening the lid might lead to it spurting out and scalding you. There is also the issue of putting handgel on your hands while smoking or holding a candle…that would be risky-ish.

The odour of ordure

If the manure they delivered with which you plan to fertilise your #AllotmentLife soil still smells of manure then it has not rotted down sufficiently to be a good fertiliser that won’t compromise the growth of root vegetables, such as carrots and parsnips, for instance.

I’ve not worked out exactly why, but a likely explanation is that you want root veg to probe deep and grow their tap root a long way into the soil, if the nutrients they need are near the surface and at high concentrations, then they won’t need to probe so deeply to feed the green part of the plant and to bloom so that they might reproduce. But that doesn’t really explain why if you plant carrots on soil with fresh horse manure as fertiliser they tend to bifurcate into two roots and roots with side-arms etc.

Anyway, allotmenteer friends had a delivery. The horse muck is apparently well rotted and we’re to take a dozen barrels if we want it for our own plot. Right next to that male is some bovine ordure, bullsh*t to you and me…although actually its from bullocks rather than bulls, a minor detail. It doesn’t look half as wholesome as the more pebbly horse dung though, more like a big pile of claggy brown mud full of straw. Not fun to shovel over the plot I wouldn’t have thought.

What is Esketamine?

You may have seen that an antidepressant called “Esketamine” has been approved for use in the UK. Sounds a bit like ketamine you’re thinking, and you’d be right. It is a purified form of the more well-known drug, commonly thought of as a horse tranquiliser and often used as a drug of abuse.

Many drug molecules come in two forms, what you might refer to as a left-handed and a right-handed form. When they are manufactured, both the left (known as the S) and the right (labelled R) form are produced, usually in equal quantities. Often one form, R or S is more active than the other, as is the case with the painkiller ibuprofen.

Sometimes, one form is active and the other form causes side effects. This is the case with thalidomide, although the forms are interconverted in the body so it is impossible to make a safe form of that particular drug for women who are or might get pregnant.

Standard manufacture of ketamine produces the R and the S form, (R,S)-2-(2-chlorophenyl)-2-(methylamino)cyclohexanone. The R form, interacts with additional receptors in the body that are not the chosen target of the drug and so lead to side effects. Hence, the need to produce ketamine as the S form only for use in treating depression. The drug S-ketamine, thus becomes esketamine. The S form is twice as potent as the mixture of R and S. The R form is nominally arketamine, clever naming.

Esketamine is marketed as Ketanest and Spravato, commonly used as a general anesthetic (intravenous) and now for severe, treatment-resistant depression (nasal spray). The drug acts by blocking the NMDA (N-methyl-D-aspartate) receptor in the nervous system and also acts as dopamine reuptake inhibitor. Dopamine release is associated with pleasure and feelings of reward, these feelings can, theory goes, be made to last longer if the dopamine remains active and is not “reuptaken” back into nerve cells too quickly.

Ketamine can be addictive and so can its S enantiomer, esketamine, which as mentioned has now been approved in the UK. Some physicians are concerned about its use. Addictive nature aside, there is the issue that esketamine increases glucose metabolism in the frontal cortex of the brain and this may be responsible for the more psychologically dissociative and hallucinogenic effects of esketamine. Arketamine decreases glucose metabolism in the brain and is thus reportedly more relaxing.

On balance, the ratio of benefits to risk is considered high enough that it can be safely used for some patients with severe and very debilitating forms of depression.

Footnote

The one thing I’ve not yet ascertained is whether or not the manufacture of esketamine begins with the 50:50 racemic mixture of the R and S forms and involves their separation prior to formulation of esketamine or whether the manufacturer has an enantioselective synthetic route that gives them a bigger proportion of the S form and less waste when they remove the R form prior to formulation. Luddchem pointed out a cyclodextrin paper published by Wiley here.

The (New) Elements Song

I mentioned my friend Helen Arney‘s marvellous update of the classic chemical song by Tom Lehrer a while back (December 2016). Now, the team from the Royal Society of Chemistry’s Chemistry World magazine, led by another, Ben Valsler, have crowdsourced a choir to join Helen and Waterbeach Brass (the brass band from the village eastwards across the A10 road from us here in Cottenham) to record a new rendition as we come to the finale of the International Year of the Periodic Table. It’s super!

A green moth that’s almost white

TL:DR – There are numerous green moths, they have evolved to mimic leaves and so evade predators through a simple camouflage mechanism.

The Light Emerald, is a geometer moth (its larvae are inchworms, measuring the earth). It is a delicate green, but not always, sometimes the green is stronger, sometimes it’s almost not green at all, but you can still tell that it is Campaea margaritaria. I had a very pale specimen to the scientific moth trap in June 2019 and posted a photo along with other interesting moths that were drawn to the actinic light.

A colleague, Martin Honey, on the Moths UK Flying Tonight Facebook group commented that he was aware of chemical research into the green pigment in this species and how it is known to be a less stable compound than any of the green pigments in an entirely different group of moths that sometimes have green, the noctuids, also known as the owlets.

An almost white Light Emerald, it’s green pigment has degraded

The paper is from 1994 and explains the chemistry of the Light Emerald green: The chemistry and systematic importance of the green wing pigment in emerald moths (Lepidopera: Geometridae, Geometrinae). You can read about the research here. It’s definitely something I might have written about back in the day when I was doing weekly chemistry news for New Scientist magazine and others.

The green pigment in question is called geoverdin and it is the only green pigment the moth needs. Chemically speaking it was once thought to be a bile pigment, but it turns out to actually be a derivative of the green pigment from photosynthesising plants, chlorophyll, consumed during the moth’s larval (caterpillar) stage. The researchers in the paper cited used good-old thin-layer chromatography to give the elusive moth pigment a little TLC and discern its characteristics.

Unfortunately, the team does not show the structure in their paper and a search for any other reference turns up nothing. However, I did find reference to the original PhD thesis from which the research paper was derived wherein it suggests that geoverdin is derived from neither bile pigments nor chlorophyll. I’ve contacted one of the team to find out more and will hopefully be able to update this post soon.

Moths, dull, grey, night-flying insects?

Ask anyone who isn’t a moth-er to describe a moth and usually terms such as dull, grey, brown, night-flying, drab, dingy, useless are the ones that arise. Someone might go so far as to describe them as the boring relatives of butterflies. Well semantics aside, butterflies are just a sub-group of the moths, they’re all Lepidoptera, but they’re anything but useless and many of them fly during the day and are incredibly vivid and bright.

Perhaps the most vivid and bright of the British species is a moth I’d not seen until today, only in books. It is the Emperor Moth, Saturnia pavonia, the only member of the Saturniidae, the silk moths, found in the British Isles.

The males are very brightly coloured, the females a version where the colours look as if they have been desaturated. The male flies during the day, the female at night. Both male and female have a vivid spot on each fore- and hind-wing that give them the appearance of having two pairs of eyes looking back at a predator. The species is actually fairly common across the British Isles although it favours heathery heathland and open country, but that does include Fenland, of which we have plenty hereabouts.

Female Emperors [should that be Empress moths? Ed.*] exude a pheromone to alert the day-flying males to their presence and their urge to mate. The males can detect picograms of sex pheromone on the wing with their feathery antennae. Purportedly, they can sniff out a female from up to ten miles.

Other Saturniidae moths in Japan and the Americas seem to use hexadecadienals and esters of those compounds as their sex pheromones. I’m yet to find a paper that isolated and characterised the sex pheromone of S pavonia. Nevertheless, you can buy a little lure impregnated with the sex pheromone. A moth-er might hang such a lure in the garden on a sunny and breezy day in the hope of attracting an Emperor, which is what I did.

First sighting was today. He wouldn’t settleÂ and I couldn’t safely net him, so I snapped away 100+ shots and maybe got 4 where the moth is in focus and in the frame.

*There is no “Ed.” it’s just me.

Shallow questions and deep answers

@EstOdek on Twitter asked her followers a simple-seeming question

What did you want to be when you were a kid? And what are you now?

Her answer to kickstart the thread:

I wanted to be a professional rugby player or boxer. I'm now an antibody selections scientist

Well, I was born just before the Moon landings era and grew up reading every single science book I could find in the library from the space books to the dinosaurs and the sharks and whales. There was a series of novels about a team or marine biologists following the submarine passion for sharks, whales, and all the creatures of the sea. And, inspired as an 8-year old I thought I’d probably forsake being an astronaut and be a marine biologist. There was even a Marine Laboratory in the bay of my hometown of Cullercoats on the edge of Northumberland.

I don’t think I’ve ever stopped reading, always have 2-3 books on the go at once, usually a novel, and a couple of non-fiction (these days, they might be about songs, snaps, or science). By the time I got to that career-choosing age where they seem to push you along based on simply how well you pass or how badly you fail trivial memory-recall tests they call examinations, I was doing all the schools sciences – biology, chemistry, physics – and maths and the obligatory humanities ones but not music, despite getting 98% in the exam and being second in the year (I learned saxophone for a couple of terms but it used to give me headaches so I gave up. Nobody nudged me towards piano or guitar lessons, I ended up teaching myself the latter and taking a few lessons on the former when I was about 17).

Anyway, by the time O-levels came around, my biology teacher was advising me to not take that subject at A-level. So, I ended up doing maths, physics, and chemistry. The unholy trinity for boys at the time, only girls got nudged towards biology in my school for some reason. Anyway, at A-level mock exams my physics tutor was advising me to not do physics but to take chemistry at university. It feels like a shame so many years later, although I did eventually fall in love with chemistry, but it just wasn’t sharks and dinosaurs! That said, I did like all the bio and med stuff in the degree more than the inorganic content. The chemistry and all those books became the passion and as I’ve discussed several times on this blog I (obviously) became a science writer.

So, today, a close friend said they hadn’t realised that about my “career path”. I wasn’t shocked that they didn’t know, childhood passions kind of fade from memory, and although we’ve had a lot of late-night conversations where such discussion might arise, that particular one has not surfaced over a single malt.

But! Look!!!

Birds, moths, butterflies, sharks, dolphins, seals, stoats, burying beetles, bees, flowers!!!

Of course, none of this post is about regrets, you take the path you take.