I Made This To Put On My Wall For Revision, But I Thought It Might Be Helpful For Some Of You Guys Too

Photographer Florent Tanet’s precarious (non-photoshopped) ‘equilibrium’ series

Molecule of the Day - DDT

Dichlorodiphenyltrichloroethane (C14H9Cl5), more commonly known as DDT, is a colourless, tasteless solid under room conditions. It was used as an insecticide during the 1940s-1970s, and gained notoriety after Rachel Carson’s 1962 book, Silent Spring, which highlighted the health and environmental effects of DDT.

DDT acts by binding to voltage-gated sodium ion channels of neurons (as seen on the left of the diagram below), causing these channels to be permanently open instead of opening only upon the arrival of an action potential. Consequently, there is a continuous influx of Na+ ions into the neuron, which triggers a series of rapid action potentials and hence neuronal impulses. This leads to rapid muscle contractions, spasms, and death.

While this effect does not occur in humans and other non-insects, it is still moderately toxic, and as been shown to be an endocrine disruptor. Therefore, chronic exposure to it can lead to tumour formation, developmental problems, and birth defects. DDT is also considered to be a possible carcinogen.

Due to the hydrophobicity of DDT, it tends to accumulate in the lipids of living organisms rather than in the environment. This results in biomagnification, in which its concentration increases upon going up the food chain, as each organism of a rung of the chain consumes multiple prey. Consequently, the usage of DDT affected the populations of many birds of prey, such as the bald eagle.

In 1962, Rachel Carson published the book Silent Spring, which highlighted the negative effects of the usage of DDT and other pesticides on the environment and biodiversity. This book was revolutionary; it sparked a heated debate on pesticides and contributed to the 1972 US ban on DDT. The world followed suit; most countries around the world now prohibit the use of DDT, except for limited disease vector control purposes, such as for malaria.

DDT is synthesised by the condensation of a molecule of chloral and 2 molecules of chlorobenzene via an electrophilic substitution reaction, producing water as a by-product.

The hairstyle of this small girl, cut short and topped with a ribbon bow, seems to date this advertisement from the early 1950s. The printer is believed to be Whitcombe & Tombs, because the poster came to the Library with other material printed by that company.

[Whitcombe & Tombs Ltd?] :Goodness! that’s tempting. Weet-bix [ca 1954?]

Eph-C-FOOD-Whitcombe-2-03

Discovering the daily life during jomon period - 縄文人の生活再現 

On this date in 1884, the first edition of what would become the Oxford English Dictionary was published under the name A New English Dictionary on Historical Principles; Founded Mainly on the Materials Collected by The Philological Society. Research for the OED had begun in 1857, when the Philological Society in London established an “Unregistered Words Committee” to find words that were either poorly defined, or absent from contemporary dictionaries. When the list of unregistered words outnumbered the amount of words found in nineteenth-century dictionaries, the group decided to write their own. The Oxford University Press agreed to publish the dictionary in 1879, and the group published the first fascicle – which covered A to Ant –in 1884 to disappointing sales. It wasn’t until 1928 that the final fascicle was published, totaling 128 fascicles in total.

In 1933, a thirteen-volume set including all fascicles and a one-volume supplement went on sale under its current name: Oxford English Dictionary – only seventy-six years in the making!

Pictured above is our well-loved copy of that historic first fascicle, which includes the preface to the dictionary and entries A through Ant. While the volume is huge and a little intimidating, it was only the beginning to what would become the most comprehensive dictionary in the English language.

Ed. James A.H. Murray. A New English Dictionary on Historical Principles; Founded Mainly on the Materials Collected by The Philological Society v. 1. Oxford: Clarendon Press, 1888. 423 M96 v. 1.

How many did you know? All worth reading more about!!

11 New Facts Science Has Revealed About The Body

1. Hundreds of genes spring to life after you die - and they keep functioning for up to four days. 

2. Livers grow by almost half during waking hours. 

3. The root cause of eczema has finally been identified.

4. We were wrong - the testes are connected to the immune system after all. 

5. The causes of hair loss and greying are linked, and for the first time, scientists have identified the cells responsible.

6. A brand new human organ has been classified - the mesentery - an organ that’s been hiding in plain sight in our digestive system this whole time.

7. An unexpected new lung function has been found - they also play a key role in blood production, with the ability to produce more than 10 million platelets (tiny blood cells) per hour.

8. Your appendix might actually be serving an important biological function- and one that our species isn’t ready to give up just yet.

9. The brain literally starts eating itself when it doesn’t get enough sleep. brain to clear a huge amount of neurons and synaptic connections away.

10. Neuroscientists have discovered a whole new role for the brain’s cerebellum - it could actually play a key role in shaping human behaviour.

11. Our gut bacteria are messing with us in ways we could never have imagined.  Neurodegenerative diseases like Parkinson’s might actually start out in the gut, rather than the brain, and there’s mounting evidence that the human microbiome could be to blame for chronic fatigue syndrome.

The Screwtape Letters C S Lewis London Geoffrey Bles - The Centenary Press 1942 - First Published February 1942, Reprinted March 1942, Reprinted March 1942

dedicated to J R R Tolkien

Molecule of the Day: VX

VX (C11H26NO2PS) is a colourless, odourless, oily liquid under room temperatures. It is a member of the V-series of nerve agents, and is an extremely potent poison - only 0.01 grams of it is needed to kill a person by skin contact. VX was recently implicated in the assassination of Kim Jong-nam, the half-brother of the North Korean leader Kim Jong-un, in Malaysia.

VX is a potent inhibitor of acetylcholinesterase, which breaks down the neurotransmitter acetylcholine into acetic acid and choline. The normal function of the enzyme is to regulate the concentration of acetylcholine within the synaptic cleft, so as to control the frequency of binding of acetylcholine to cholinergic receptors on the postsynaptic cell membrane and hence the transmission of impulses across the synapse.

Consequently, the inhibition of acetylcholinesterase results in a rapid increase in the synaptic concentration of acetylcholine, as the presynaptic knob continues to synthesise it and secrete it into the synaptic cleft. As a result, the cholinergic receptors on the postsynaptic cell membrane are continually stimulated, and a rapid series of action potentials are triggered. This results in muscle spasms and eventual paralysis, leading to death by asphyxiation due to paralysis of the diaphragm.

VX exposure is usually treated using an injection of atropine and pralidoxime. Atropine inhibits certain cholinergic receptors, reducing the binding of acetylcholine to receptors and thus the triggering of action potentials. On the other hand, one end of pralidoxime binds to acetylcholinesterase and the other binds to the phosphate group of VX, which causes the VX molecule to detach from the enzyme together with the pralidoxime molecule (see below). This restores the ability of acetylcholinesterase to hydrolyse acetylcholine, hence reducing its synaptic levels.

VX is synthesised from phosphorus trichloride over multiple steps; first, it is methylated, reacted with ethanol, then transesterified with N,N-diisopropylaminoethanol to produce QL. This is then oxidised with sulfur, and isomerised via heating to produce VX.

The anime ‘Romeo’s Blue Skies’ is based on a book about a true event which happened in the south of Switzerland unti the 19th century: young boys being sold to Milano to work there as chimney sweepers. There is also a German movie about it called ‘Die Schwarzen Brüder’ [the Black Brothers]. You can watch the trailer here