The Causes of Hangovers

If you want to make two dull but reliable predictions,  one would be that the sun will still be there for us in 2017. Our star will continue to offer stability for another 5 billion years, a number as hard to imagine as the fact that France produces 4.3 billion litres of wine annually. Another sure-to-materialize prediction is that a fair number of people will overindulge in drinking alcohol on New Year’s Eve and wake up with a hangover.

hungover-gq-magazine-january-2014-hangover-06

from GQ magazine

Is alcohol the only cause of the hangover? It is its main cause,  but the severity of a hangover is correlated with a higher concentration of congeners. Congeners are minor compounds that appear in alcoholic drinks as a result of both fermentation and distillation. These include amyl alcohols, methanol, acetone, furfural and tannins.

congeners

Before examining congeners, let’s look at ethanol itself, the main active ingredient in alcoholic drinks. The common explanation as to why alcohol causes hangovers is based on the compound’s ability to cause dehydration. But the biochemistry involved seems to be more complicated than that. The best hypothesis out there is based on cytokine levels. Excessive drinking raises levels of pro-inflammatory cytokine. In general cytokines are small proteins that play important roles in cell signalling. There are receptors for cytokines in the brain, especially in the hippocampus, a structure important in forming memories, so the memory-impairment from heavy drinking could very well be linked to cytokines. In a study where cytokines’ concentration was raised by injecting patients with 0.8 nanograms of S abortus equi endotoxin per kilogram of body weight, a “global decrease of memory function was observed” .

There is also evidence that a pair of cerebral cytokines (IL-1β and IL-6) and tumour necrosis factor (TNF-α) lead to malaise similar to hangover. For example in animals, elevated levels of cytokine cause weakness, inability to concentrate, decreased appetite, reduced activity, sleepiness, and loss of interest in everyday activities such as calculus. As recently as last year , research continued to provide evidence that cytokine levels are high during hangover.

So do congeners accentuate that mechanism? It’s not known yet. But bourban, brandy and red wine have the highest concentrations of congeners ( about 30 to 55 mg per liter) and produce more severe hangovers than vodka, which is low in congeners.

I have had only one hangover in my life, over 35 years ago, and I have not been drunk since. Once we start drinking our judgement is impaired, leading us to drink more, and I don’t like to yield my control to a single type of molecule.  I’m also lucky to have had a life so far in which I want to remember more than what I want to forget, so alcohol is of little use to me. Except for a few good-tasting wines and beers, most alcoholic drinks also taste like poison.

Although no one in 2017 will find a general cure for all the different diseases labelled as cancer, I hope that more people will take prevention seriously. It’s not common knowledge that alcohol is a very dose-dependent class 1 carcinogen. For example, if women refrain from doubling the recommended maximum intake of 14 units of alcohol per week(equivalent of 1.6 bottles of 12% wine), about 30 more women per 1000 will avoid breast cancer. Men are not as sensitive to alcohol from a cancer-perspective, but they are not immune to it either. The National Cancer Institute site does a good job outlining which cancers are associated with alcohol and the amounts of drinking involved. Why alcohol is carcinogenic is probably related to

(1) the genotoxic effects of its metabolite, acetaldehyde;

(2)to its ability to raise estrogen levels ( hence its breast cancer-causing role)

(3) to the reactive nitrogen and oxygen species it produces

(4) and to its ability to act as a solvent for other carcinogens, especially those in tobacco smoke.

So avoid a hangover and reduce your chances of cancer by toasting the New Year with only a test tube’s worth of champagne!

Other Sources:

http://onlinelibrary.wiley.com/doi/10.1111/j.1530-0277.2009.01116.x/full

http://alcalc.oxfordjournals.org/content/43/2/124.full

http://dspace.library.uu.nl/handle/1874/330093

http://www.thelancet.com/journals/lanonc/article/PIIS1470-2045(06)70577-0/abstract?cc=y=

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The Physics of Snowflakes & the Spirit of Christmas

We shovel snow from our door steps because although no two snowflakes are alike, far more than two land in the same place. Rigorous shovelling helps beat the cold. and once warmed up, we can think about falling snowflakes. And if we want to be even more captivated, we can observe them.

First the thinking part. If we want to merely predict the velocity of falling snowflakes, we already run into a complication. At least raindrops begin as spheres, and then as they grow larger, their shape approximates that of a burger bun. That affects their area and drag coefficient —numbers needed in assessing to what extent air slows down the rate of falling drops. But snowflakes are formed in a countless variety of shapes and sizes. There is far more averaging out to do.

So assume that it’s been done. We subsequently write an expression for the product of air density, the flakes’ average area, their average total drag coefficient and square of their velocity. Then we subtract that expression from the force of gravity. The difference will equal to the so-called net force, which is the product of mass and rate of change of velocity with respect to time—Newton’s Second Law.

In our differential equation, velocity appears on the equation’s two sides, one of which also has the variable of time. Isolating the variables and using appropriate substitutions allows us to integrate and solve for velocity. As the time that the snowflake falls increases, exponential terms drop out of the equation, and the flake’s terminal velocity seems to depend only on the  the snowflake’s mass and the shape -influenced and gravitational constants we mentioned earlier.

8051109Now we observe. As we stated at the onset, many snowflakes land in the same place. But only a few meters above any given spot, it is apparent that many paths lead to a common destination. Some flakes tumble; some abandon the terminal velocity we took so long to calculate, and they yield themselves to whimsical eddies. How they arrive is influenced not only by shape, mass and gravity but by sheer luck—luck due to the random, pinpoint fluctuations in temperature and pressure that affect their air space.

And these unpredictable*, forgotten, dance-like movements of deviant snowflakes open our eyes and widen our mouths. They drain our minds of thoughts of shovelling and of future slush and social conflicts. For a few moments the destinies of snowflakes is all that matters, and then we are reminded of a beautiful, non-mathematical expression in which snow is equated with Christmas.

*N.B. In reality the larger snowflakes may behave like sheets of falling paper which experience aerodynamic lift, a lift dominated by the product of linear and angular velocities. Those of you interested in computer simulations of falling snow might find this link interesting: https://www.cs.rpi.edu/~cutler/classes/advancedgraphics/S08/final_projects/fermeglia_willmore.pdf

Cosmic Origins of Atoms in a Mineral

A mineral is more pure than its parent rock. But compared to food additives, industrial compounds and pharmaceuticals, a mineral’s compound often hosts more elements. As a result it isn’t difficult to find a mineral whose atoms have a variety of cosmic origins.

Only a small percentage of elements on Earth are created in and around the planet by nuclear reactions, and even at that, they are only derivatives of atoms made elsewhere. The secondary creations result from the atmosphere’s interaction with cosmic rays, from the lithosphere’s minority of radioactive elements, from nuclear reactors and from scientific research—my favorite being the tanks that sit deep in abandoned mines collecting neutrinos from our sun and supernovae.

pezzottaite-256889

pezzottaite

So where in space did the majority of constituents of the living-geological continuum originate and by what mechanism? Let’s look at the cosmic roots of the six elements of a mineral known as pezzottaite, discovered in Madagascar and only officially recognized as a distinct mineral in 2003. Its formula is Cs(Be2Li)Al2Si6O18

Oxygen

What’s the ultimate source of oxygen? Big or small, stars spend the bulk of their time on the main sequence, a hydrogen-fusing stage that actually lasts longer for smaller stars. This is because a star’s lifetime is proportional to its mass but inversely proportional to the fourth power of its core temperature. Although small stars have less hydrogen, the smallest of the chemical elements, they also fuse it at a lower temperature from the lower force acting on its core. The product of the sequence of reactions involved in the fusion of hydrogen is helium. While helium grows as an onion-like outer-layer during its residence as a main sequence star, the temperature isn’t high enough to fuse the helium into bigger elements. But when the hydrogen fuel runs out, the star is for a while no longer in equilibrium. The outward radiative pressure isn’t there to balance out gravity, so the large force towards the star’s center “ignites” the fusion of helium and the star becomes a red giant.

red-giant

from J. Chem. Educ., 1990, 67(9), p 726

When the star’s core temperature reaches 108 K, from the diagram we see a pair of helium nuclei fusing to form an unstable beryllium nucleus, which then fuses to give us the life-essential carbon. This in turn fuses with another helium to produce oxygen. Oxygen can continue to fuse, but there are enough nuclei that remain as such. When stars, in a later stage of their evolution, either shed their outer layers either as a planetary nebula or supernova, stellar dust receives these oxygen atoms, some of which ended up in our water , skin and in our pezzottaite.

Silicon

To get silicon we need a more massive star capable of generating a red-giant-temperature and density of 500 million K and 5 million g/cm3. Under these conditions two oxygens (atomic number 8) will combine to create a silicon nucleus(atomic number 16). Fittingly some of this product and progenitor are eventually reunited on planets as sand, sandstone, quartz, clay and a wide variety of minerals that contain either silica or some form of silicate— including that of pezzottaite.

Lithium and Beryllium

A neat thing about pezzottaite is that it has two(lithium and beryllium) of three light elements that are relatively rare in the universe. The presence of each of lithium, beryllium and boron is only one billionth that of hydrogen and about a millionth of that of carbon, nitrogen and oxygen. The reason for this is that the bulk of Li, Be and B do not survive any of the stages of stellar evolution. Their fragile nature suggested they were synthesized in low-density, low-temperature environments.

galactiv

The broken line represents solar system abundance of the elements Li, Be and B. The solid line shows enrichment found in galactic cosmic rays. From J Chem Ed 1990, 67(9)p 729

One area where a high concentration of these light elements occurred was in galactic cosmic rays. This suggested that perhaps they are not being carried from elsewhere but being synthesized on the spot by the nuclear reaction between alpha particles(helium nuclei) or protons of the cosmic rays and larger elements like carbon, nitrogen and oxygen. This process is now called spallation. While other genesis-models failed to predict the exact concentrations of the isotopes, the spallation hypothesis came closest to account for the relative ratios.

cyclotron

scan from scientific American May 1987, from an article by researchers Viola and Mattheson

In the 1980s Viola and Mattheson used a cyclotron to accelerate protons and helium nuclei to the energies of cosmic rays and aimed them at targets of He, N, C and O to generate new nuclei. When the particles’ energies and speeds were analyzed, their calculated masses allowed them to identify the isotopes. Their abundance was similar to that found in galactic cosmic rays. The three reactions that created a fair amount of the lithium and beryllium in our pezzottaite are:

4He + 12C → 7Li + 2  4He + 1H (main isotope of lithium, 92.5% of what’s found on Earth)

2 4He → 6Li  + 1H + 10n

1H+ 14 N  →9Be + 4He + 2 1H

One anomaly, however, was that the amount of 7Li ( the heavier isotope) made in the cyclotron was a little lower than what’s actually found in space, suggesting that a minority of 7Li was not made in the cosmic rays but originated elsewhere. Some of the discrepancy is partly accounted for by the small amount made in the Big Bang, but in 2013, analyses of the Subaru Telescope High Dispersion Spectrograph revealed that a more significant contribution comes from novae. Smaller stars eventually become white dwarfs after passing through the red giant stage. But these remnants, if part of a binary system, could suddenly brighten from explosive nuclear reactions when material from its partner-star is pulled onto the dwarf’s surface. The nuclear reactions create a different series of elements compared to those produced in stellar interiors or during supernova explosions. One of these atypical reactions is the conversion of beryllium-7 to lithium-7 by electron capture, which lowers the atomic number without affecting the atomic mass.

Cesium

To explain the origin of the final two elemental components of pezzottaite, Al and Cs we need to examine supernovae. The next avenue of evolution of large stars is a type II supernova, which briefly outshines its entire galaxy. When all fuel is spent in large stars iron is left at the stellar core and a gravitational collapse ensues. In a rapid process-set of reactions ( r-process), neutrons  are initially generated by the gravitational collapse during photodisintegration, a process where gamma causes the fission of heavier nuclei. For example here’s a sequence of reactions generating a total of 7 neutrons from a single iron nucleus:

56Fe + ϒ → 13  4He + 4 10n
4He + ϒ → 2 ‘H + 2 10n

‘H + e- →   10n + ν

Then in the actual r-process neutrons are captured to form unstable neutron-rich isotopes which then undergo beta decay and turn into elements of higher atomic number.How does this happen? A little background info: Being electrically neutral, neutrons can penetrate the positively charged nucleus, especially at low temperatures. But free-roaming neutrons are short-lived lasting only about ten minutes as one of their down-quarks becomes an upquark, a process that generates a proton, a beta particle and an antineutrino. This raises the atomic number by 1. To generate sufficient numbers of neutrons and provide a constant supply of these ephemeral neutral particles, the high-energy environment of something like a supernova is needed. For example with the provided energy, gamma will break down enough iron to generate  enough neutrons, which in turn can convert other iron atoms (atomic number 26) into heavier iron isotopes, one of which will beta-decay into cobalt (number 27). That isotope of cobalt can then absorb more neutrons and eventually undergo beta decay to create an even higher-numbered element, Ni. The isotopes created by the r-process are not the stable ones of the heavier elements. But they can later become stable ones by undergoing fission and beta decay.

Once the stellar material has been enriched with the ejection of these new atoms, subsequent generations of stars can generate other isotopes in the slow process (s -process), which also involves absorption of neutrons but at a slower rate. In a less violent environment such as that of a red giant, the absorbed neutron has time to decay into a proton so it tends to produce isotopes of medium to lower atomic numbers. For example some of  pezzottaite’s cesium 133 (atomic number 55) could have been directly produced by the breakdown of an isotope created by the r-process or it could have formed later in another generation of stars by the beta-decay of  xenon 133:

13354 Xe  →133 55 Cs +0 -1 β

As shown in the diagram below, the unstable xenon 133 isotope was in itself generated by s-process. A 5-step sequence of neutron-absorption beginning with xenon-128 took place. In an r-process environment, more neutrons would have been absorbed before beta decay would have been possible.

cesium

Illustration of the r and s processes operating in the vicinity of cesium’s neighbors. each square is a stable isotope, like that of 133 Cs. The horizontal solid arrows represent neutron capture, while the wavy diagonal arrows represent beta decay. The isotopes represented by white boxes result from either the s or r process. The blue boxes represent isotopes that result only from the r process, while the red boxes are s-only isotopes. The yellow boxes represent isotopes produced by proton capture. from https://answersingenesis.org/astronomy/solar-system/discussion-stellar-nucleosynthesis/

Aluminum

Finally we get to aluminum. Before becoming a type II supernova, there is an important set of reactions that occurs in the core of a star exceeding 8-11 solar masses. Silicon burning -reactions mainly begin with silicon(atomic number 14) and add on a helium nucleus, creating sulfur(16), argon(18), and so on until iron is formed. But above a critical temperature  explosive silicon burning photodisintegrates all nuclei and rebuilds them up during the expansion. In one of these reactions magnesium-26 captures a proton to form aluminum 27.

William Blake was right. There is indeed a world in a grain of sand—and, we may add, a universe in a mineral.

Sources:

Formation of the Chemical Elements and the Evolution &
of Our Universe, V. E. Viola Journal of Chemical Education, 1990, 67 (9)

Scientific American   Grant J. Mathews, Victor E. Viola  May, 1987

Click to access thielemann.pdf

http://subarutelescope.org/Pressrelease/2015/02/18/index.html

Click to access thielemann.pdf

http://www.aanda.org/articles/aa/full_html/2013/11/aa22599-13/aa22599-13.html

http://adsabs.harvard.edu/full/1971ApJ…166..153A

https://answersingenesis.org/astronomy/solar-system/discussion-stellar-nucleosynthesis/

https://en.wikipedia.org/wiki/Silicon-burning_process

http://abyss.uoregon.edu/~js/ast122/lectures/lec18.html

http://pages.uoregon.edu/jimbrau/astr122-2009/Notes/Exam2rev.html