You're asking a very good question and we understand some aspects of it, but not all of them, nor is there a single comprehensive theory that fully explains all aspects of memory storage and retrieval. But first, one point of clarification, most neurons are not replaced during life. Except for sensory neurons in the olfactory bulb and a sub-set of neurons in the hippocampus, the neurons we have in our brains are the same throughout our lives.

Just to get encoding/decoding out of the way, information the obtain through our sensory receptors is parceled out (primarily through the thalamus and related ganglia) to different regions of our cerebral cortex: vision (occipital lobe), somatosensory (parietal lobe), auditory (temporal lobe), higher cognitive function (frontal lobe), and movement and motor skills (cerebellum). For movement or behavior in general, the individual draws from information saved in these areas.

Now to address your question. In the cortical areas mentioned above, neurons contact other neurons at synapses (the places where neurotransmitters are released from one neuron to another to either increase (excitatory) or decrease (inhibitory) the potential of the second neuron firing. And thus it continues from neuron to neuron. When neurotransmitters repeatedly act in synapse, in addition to causing the post-synaptic neuron to fire, they elicit subtle changes both pre- and post-synaptically. Pre-synaptically, these changes include increases in the number of NT-containing vesicles formed along with enzymatic modifications to increase how much NT is released. Post-synaptically, the numbers of NT receptors increase, as do the numbers of dendrites, and other changes referred to collectively as "post-synaptic densities." Over time and many thousands of times fired, the synapse becomes "stronger" or more able to fire (a model for this is calls it long-term potentiation or LTP).

This is what happens at a single neuronal synapse and it's the fundamental "unit" of memory, however note that each neuron receives input from about 1,000 neurons and provides output to another 1,000 neurons, and there are many, many neurons in the cortices (I don't recall how many, but there's an estimate for the entire brain of 10 to the 11th power that's sometimes mentioned.

Somehow, all of these individual synaptic changes give rise to memories and learned behaviors, but alas, we don't understand the full sequence of how this processing occurs.

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Also rimonabant was removed from the market due to suicidal ideation. It's a CB1 inverse agonist that acts on the cannabanoid receptor opposite to how marijuana does with the idea being that it would suppress appetite and aid weightloss. It worked (modestly) but it also made people think about killing themselves. That got it removed from the market pretty quickly.

https://en.wikipedia.org/wiki/Rimonabant

There are several classes of drugs that are known to have depressive side effects (including some heart medications that affect ion channels, and some medications that affect hormones). Usually these are quite minor as a medication would not be approved by the FDA if depression was a major side effect.

Currently the FDA has a black box warning for suicidal ideation for SSRI's (an anti-depressant). Generally the increase in suicidal ideation occurs within a month or so of initiating treatment before the risk begins to reduce to that of someone without depression. The mechanism for this is unknown although its been proposed that there is a brief phase where the treatment increases motivation/energy before mood. There have been several critiques of the link between suicide and SSRI's with the main points being that the link exists in adolescents and children but not adults. Thus pooled analyses lose this distinction.

Suicidal ideation following anti-depressant initiation - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9178080/

Critique on the link between suicide and anti-depressant-
https://pubmed.ncbi.nlm.nih.gov/31130881/

Medications with depressive side effects - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2729620/

For those seeking help regarding suicide -
https://988lifeline.org/

It refers to all DNA, not just coding sequences.

Sequencing all the coding sequences is called whole exome sequencing.

Researcher here. Medical device companies are working on this. Continuous glucose monitors do this with interstitial fluid, and Dexcom is investigating applying these technologies for other molecules.

A big consideration is the thing you want to measure, which tissues you can access, and whether it’s an appropriate approach. Blood is accessible and a lot, but not all, of health related things are released or leaked into blood. For example Vitamin D measurement in blood is tricky.

Advil, or Ibuprofen, binds to an enzyme called cyclooxygenase (COX-1 and COX-2). It blocks the beginning of a pathway (maybe someone else can fill in this part for me) that leads to inflammation. It is a non-steroidal anti inflammatory drug (NSAID).

To begin with we would have to know what headaches are on a mechanistic level and at least when I took a neurophysiology of pain course in grad school the answer was pretty unclear.

Upfront: some of it is a very slight form of racism. Used to be called Chinese Restaurant Syndrome.

You eat about 10-20 mg of glutamate a day in a normal diet. It's in cheese, tomatoes, soy sauce, soy-anything like protein boosted meals, roasted meats - essentially it's in anything that tastes savoury.

There is no difference between MSG or naturally occurring glutamate in other foods. Your body sees those as being exactly the same. It's just normal glutamate that has been mixed with salt and dried.

Next, the science. First, MSG not been proved to to be linked to headaches. Second, there is good evidence that MSG at any concentrations has no effect on headaches.

Those are different but good stories: you can give anyone MSG and it doesn't cause migraines or headaches; If someone is susceptible to migraines or headaches, it's been shown it's not the MSG causing it.

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Wikipedia article on gun-type fission bombs..

The simple part of the gun mechanism is pushing two sub-critical lumps of U235 together to make a large enough mass to be super-critical. You could do this with your hands pushing the two lumps together and it still happens, the bullet design just makes it more efficient.

The speed of the bullet is because the super-critical chain reactions take 1 microsecond. That means you have only 1 microsecond to get the bullet to mix with the target and hopefully form something like a sphere. If the bullet is moving too slow, you get pre-detonation.

Basically, bullet too slow = the bottom blows up and wastes the remaining unreacted mass of U235 by throwing it out the top.

The bullet was hollow, but more similar to when you do the hand gesture of penis entering vagina. It kept the two lumps of material from touching for as long as possible. The hollow bullet landed on a spiked target.

Probably never because you would need an isolated population for many generations. Like 10-100 thousand years of an isolated population.

Synthetic chemistry makes the drugs and biochemistry helps understand them.

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> The recall includes the following products: Pine-Sol Scented Multi-Surface Cleaners, in Lavender Clean, Sparkling Wave and Lemon Fresh scents; CloroxPro Pine-Sol All Purpose Cleaners, in Lavender Clean, Sparkling Wave, Lemon Fresh and Orange Energy scents; and Clorox Professional Pine-Sol Lemon Fresh Cleaners.

Microbes like to eat soaps too.

The multisurface cleaners are mostly water, oils and surfactants. They are not antimicrobial.

Most of the chemicals you listed are very poor antimicrobials, IMHO they are not antimicrobial at all. They mostly work simply by being surfactants that (1) dissolve a fatty outer layer and wash off the bacteria from a surface or (2) maybe if you get lucky they lyse a really narrow class of microbes, usually just e-coli and salmonella bacteria.

Typically these products include a teeny tiny trace amount of water-based anti-microbial chemicals to keep the product shelf stable. For instance, benzyl alcohol or MIT/CIT.

It can easily be that the factory was using contaminated water and the amount of microbes exceeded the control of the antimicrobials. They factory may have had a blocked nozzle and the products either did not get enough or any antimicrobials. A worker may have messed up and put the incorrect chemical in the processing line.

Since the claim the bacteria of concern is Pseudomonas aeruginosa, IMHO that implies their factory was using ground water that became contaminated. The factory water treatment facility got contaminated or was passing, which contaminated their bottle filling equipment. In my own work history I have seen a sand filter positioned after a water treatment facility get contaminated, and nobody checked because it was not expected to ever see dirty water in the first place, so it was only noticed when during a routine stoppage and restart, the first flush of water smelled bad.