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There are plenty of good sources online explaining the principle behind radiocarbon dating. For instance, the wikipedia explains: During its life, a plant or animal is in equilibrium with its surroundings by exchanging carbon either with the atmosphere, or through its diet. It will therefore have the same proportion of $\ce{^14C}$ as the atmosphere, or in ...


9

There is a clear explanation and figure showing this in the following reference: Anton Gorkovskiy, Kent R. Thurber, Robert Tycko, Reed B. Wickner, PNAS 2014, 111 (43) E4615-E4622. A parallel beta sheet is one where the direction from N- to C-termini on adjacent strands run in a parallel direction (rather than antiparallel). In-register means that each ...


8

The metabolism of living creatures keeps the dynamic equilibrium of their $\ce{^{14}C/^{12}C}$ ratio with the enviromental $\ce{^{14}C/^{12}C}$ ratio via photosynthesis, breath, food and excrements. It is not just about one time building, but also about continuous recycling of the body content. Such an equilibrium means continuous resetting of the $t=0$ ...


6

This is a summary of the account by Peter Brzezinski, Professor of Biochemistry, Stockholm University, Member of the Nobel Committee for Chemistry from the Scientific Background document. [Brzezinski:] Jacques Dubochet developed methods for preparation of samples for cryo-EM studies of biomolecules in water. Joachim Frank developed methods for structural ...


5

For currents in biological systems the magnetic field is minuscule, and likely has no physiological effect. That said, magnetoencephalography is based on measuring the tiny magnetic fields created when nerves fire. Detection requires an incredibly sensitive detector, a superconducting quantum interference device (SQUID), to detect the location of the ...


2

Aspirin has a solubility of ~3 g/L. In addition from a patent by Galat [1]: Sodium aspirin is almost 1000 times as soluble in water as aspirin itself. All of the $\ce{NaOH}$ can be assumed to react with acetylsalicylic acid (aspirin) to form the sodium salt. This means the amount of solubilized sodium aspirin is roughly equal to the amount of added $\...


2

If you labeled the oxygen atoms in carbon dioxide in green and the oxgyen atoms in dioxygen in red (because they derived from photosynthesis, while $\ce{CO2}$ is used up in the Calvin cycle), you would have to add some water molecules to be able to write an equation like this: $$\ce{6C\color{limegreen}{\ce{O2}} + 12H2\color{red}{\ce{O}} -> C6H12\color{...


1

In addition to all the qualities @Karl stated (harmless, edible, overspray decomposes, etc.), such a coating would also need to stretch as the produce grows. Such a protective covering might even obviate the need for pesticides, if it were to be created. That said, there are edible wax and protein coatings to preserve produce after it's picked. ...


1

While we are alive, we are constantly replacing our molecules. With every breath cycle, you get rid of some of your carbon (CO2). With every meal, you take in new carbon (carbohydrates, proteins, lipids). The carbon in your body gets cycled as your cells die and are replaced. This replacement process stops when you die. After this, whatever carbon remains ...


1

In the United States, sucralose is sold under the brand Splenda. There is a liquid product with the food label shown below: The low calorie sweeteners in solid (powder) form containing sucralose come in different form, and they often contain sugars with calories. Here is one example: It contains glucose as the main ingredient. Nevertheless, they are ...


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