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Sam Kean [0-0] American
Rank: 102
Writer


Sam Kean is a writer in Washington, D.C. He has written for The New York Times Magazine, Mental Floss, Slate, Psychology Today, and The New Scientist. He has also published three books which discuss scientific discoveries in a narrative style. His books received positive reviews in The Wall Street Journal Library Journal, and The New York Times. He was born in Sioux Falls, South Dakota.

Medical

QuoteTagsRank
Guinea pigs are practically synonymous with experiments. Lab rats have become the workhorses of modern medicine. Genetics owes a huge debt to the humble fruit fly. There's almost no branch of the life sciences, in fact, that hasn't leaned heavily on one animal or another.
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Boron is carbon's neighbor on the periodic table, which means it can do a passable carbon impression and wriggle its way into the matrix of a diamond. But it has one fewer electron, so it can't quite form the same four perfect bonds.
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Except for certain moments - when cells are dividing, for instance - chromosomes don't form compact, countable bodies inside cells. Instead, they unravel and flop about, which makes counting chromosomes a bit like counting strands of ramen in a bowl.
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As a child in the early 1980s, I tended to talk with things in my mouth - food, dentist's tubes, balloons that would fly away, whatever - and if no one else was around, I'd talk anyway.
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Even fictional characters sometimes receive unwarranted medical opinions. Doctors have diagnosed Ebenezer Scrooge with OCD, Sherlock Holmes with autism, and Darth Vader with borderline personality disorder. Medical
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Most mutations involve typos: Something bumps a cell's elbow as it's copying DNA, and the wrong letter appears in a triplet - CAG becomes CCG.
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America was probably Europe's equal scientifically by the end of World War I and certainly surpassed it after the chaos of World War II.
107
If you had to sum up chemistry in one sentence, it might be this: Atoms need to have full shells of electrons to feel satisfied, and different elements steal, shed, or borrow different numbers of electrons to achieve a full shell.
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Genes are like the story, and DNA is the language that the story is written in.
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Brain surgery couldn't happen without the patient's own active voice to guide the work. The patient is part of the surgical team here, perhaps the most important part, and above all, that's what makes neurosurgery different.
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Aluminum is the most common metal in the earth's crust, almost twice as abundant as iron. And one common class of aluminum minerals, collectively called alum, has been in use since at least Greek and Roman times.
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People adored Element 13's color and luster, which reminded them of the sparkle of gold and silver - a brand-new precious metal. In fact, aluminum became more precious than gold and silver in the 19th century because it was harder to obtain.
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In some sense, what you might have suspected from the first day of high-school chemistry is true: The periodic table is a colossal waste of time. Nine out of every 10 atoms in the universe are hydrogen, the first element and the major constituent of stars. The other 10 percent of all atoms are helium.
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Cancer is really a DNA disease... We have these certain genes that prevent our cells from growing out of control at the expense of the body. And it's a pretty good, robust system. But if a couple of these genes fail, then that's when cancer starts, and cells start growing out of control.
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Genes work with probabilities; they don't work with certainties. So most things that you're looking at with these genetic tests, it's not like you're condemned to automatically get the disease or the syndrome. There's a lot of factors in play there.
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The more that I looked at DNA, the more I realized it was nature and nurture. It's how genes and your environment work together to produce the person you are.
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I'm kind of a sucker for the retro-diagnoses.
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Our evolution could have gone in different directions a lot of times. We could have gone extinct at some points. We might not have gotten our big brains, or Neanderthals might have made it while we did not.
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I didn't mind staying home from school and medicating myself with vanilla ice cream and chocolate sauce. Being sick always gave me another chance to break an old-fashioned mercury thermometer, too.
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Medieval alchemists, despite their lust for gold, considered mercury the most potent and poetic substance in the universe. As a child, I would have agreed with them.
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When first presented with the jumble of the periodic table, I scanned for mercury and couldn't find it. It is there - between gold, which is also dense and soft, and thallium, which is also poisonous. But the symbol for mercury, Hg, consists of two letters that don't even appear in its name.
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In a vague way, I always knew neurosurgery was different - more delicate, more difficult, more demanding. After all, we say things like, 'I'm no brain surgeon,' for a reason.
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Although it's the hub of the nervous system and the ultimate terminus of every nerve, the brain itself lacks enervation and therefore cannot feel pain.
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Brains, you see, vary a lot from person to person - they vary as much as faces do.
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X-rays revealed that some people were born without a corpus callosum, and they seemed just fine.
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No one knows quite the reason, but surgically severing the corpus callosum can reduce the rate and intensity of seizures. So in the early 1960s, a few patients with severe epilepsy had their corpus callosums cut, turning them into split-brain people.
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The brain, which is plastic when young, must be exposed to certain sights early in life, or it will remain blind to those sights forever.
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Those of us raised in modern cities tend to notice horizontal and vertical lines more quickly than lines at other orientations. In contrast, people raised in nomadic tribes do a better job noticing lines skewed at intermediate angles, since Mother Nature tends to work with a wider array of lines than most architects.
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The idea of critical windows extends beyond just vision, of course: almost every system in the brain has a critical window when it needs to experience certain stimuli, or it won't get wired up properly. The most obvious example is language: if you don't learn a language early on, it's nigh impossible to become truly fluent.
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Animal vision - including human vision - is so biased toward movement that we don't technically see stationary objects at all.
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The amygdala plays a crucial role in processing fear, and minus her two amygdalae, S.M. became unflappable. Studies of her are actually a hoot to read, since they basically consist of scientists concocting ever-more-elaborate ways of trying to scare her.
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Despite what you might guess, when monitoring your breathing, your body doesn't care whether you're inhaling enough oxygen. It cares only whether you're expelling enough carbon dioxide - that's the gas that sets off the panic button when you're suffocating.
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The amygdala is one of those brain structures that a lot of people know a little bit about, and there's a definite tendency to conflate the amygdala and the fear response itself - as if the amygdala, and the amygdala alone, 'causes' fear.
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The amygdala is indeed crucial for monitoring our environment and deciding what's worth getting worked up over. Once the amygdala determines this, however, it merely trips another circuit to actually produce the panic.
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Most people, even most doctors, learn that the placenta is a nice, tight seal that prevents anything in the mother's body from invading the fetus, and vice-versa. That's mostly true. But the placenta doesn't seal off the baby perfectly, and every so often, something slips across.
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In 'The Violinist's Thumb,' I talk about the poignancy of cells leaking across the placenta into both the mother and the child.
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Microchimeric sharing means that, even if the mother loses a child, she'll have a small memento of him or her secreted away inside her. Similarly, a bit of our mothers live on in all of us no matter how long ago Mom died.
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If stem cells divide equally, so both daughter cells look more or less the same, each one becomes another stem cell. If the split is unequal, neurons form prematurely.
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To be sure, ASPM isn't the gene responsible for building big brains - there's no such single gene. But it's critical to the process, and the primate line has almost certainly benefited from distinct changes in ASPM.
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I was reading this story about these people who suffered from brain injuries, and then their behavior changed kind of drastically afterward, and I just said to myself, 'There's no way that that can possibly be true.'
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What I find fascinating is the idea that we all have a physical brain, but we also have this mental part, and we have to figure out how they work together.
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DNA is a 'thing' - a chemical that sticks to your fingers.
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We human beings are humane in part because we can look beyond our biology.
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A long iron rod rocketed straight through the very forefront of Phineas Gage's brain. It's kind of an unusual part of the brain: you can suffer pretty severe injuries to it and often walk away from the injury. It's not a part of the brain that's necessarily vital for your biological self. But it is very important for personality.
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I think it's a natural human tendency, when you read something, you tend to read a lot of your prejudices into it. And neuroscience is like a lot of disciplines - it has fashions; things change.
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We really should be grateful to the people who participate in research and allow certain details to be published about themselves. Because if they didn't, we wouldn't have nearly the understanding of the brain that we do.
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Without a functioning hippocampus, names, dates, and other information falls straight through the mind like a sieve.
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The hippocampus helps record both types of memories initially, and it helps retain them for the medium term. The hippocampus also helps us access old personal memories in long-term storage in other parts of the brain.
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The humped bladderwort has yellow, snapdragon-like flowers, and it's actually carnivorous, capable of trapping and eating not just insects but even tadpoles and tiny fish.
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Most organisms have loads of junk DNA - less pejoratively, noncoding DNA - cluttering their cells.
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Things look especially bleak for common killers such as diabetes and heart disease. Those ailments clearly have a genetic component. But when scientists survey genes looking for which mutations patients have in common, they come up empty.
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Despite its obscurity, probably no element on the periodic table has as colorful a history as antimony. Money, madness, poison, linguistics, charlatanism, sex - pretty much every theme that runs through the periodic table can be found in Element 51.
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The inability to trace DNA to actual diseases has serious consequences. As does the opposite problem - not being able to trace diseases back to DNA.
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Even if we never cure a single disease, the Human Genome Project and other ventures will have been worth it.
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The most profound change that genetics brings about might not be scientific at all. It might be mental and even spiritual enrichment: a more expansive sense of who we humans are, existentially, and where we came from, and how we fit with other life on earth.
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While our amplified knowledge of genetics - and the increasing precision of the field - does make it tempting to take on celebrity cases, retro-genetics can't always provide clear answers.
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The mutated Marfan gene creates a defective version of fibrillin, a protein that provides structural support for soft tissues like blood vessels. Marfan victims often die young, in fact, after their aortas grow threadbare and rupture.
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It's often meaningless to talk about a genetic trait without also discussing the environment in which that trait appears. Sometimes, genes don't work at all until the environment awakens them.
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We know that genes shape human cultures and human societies: The DNA we inherited from our ancestors makes certain foods taste better, affects the way we care for children, influences what colors we find vibrant, and contributes to our love of socializing, among other examples.
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Junk DNA - or, as scientists call it nowadays, noncoding DNA - remains a mystery: No one knows how much of it is essential for life.
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Mutations can arise anywhere in the genome, in gene DNA and noncoding DNA alike. But mutations to genes have bigger consequences: They can disable proteins and kill a creature.
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The grand saga of how humans spread across the globe will need some amendments and annotations - rendezvous here, elopements there, and the commingling of genes most everywhere.
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Geneticists in the early 1900s believed that nature - in an effort to avoid wasting precious space within chromosomes - would pack as many genes into each chromosome as possible.
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Before the Human Genome Project, most scientists assumed, based on our complex brains and behaviors, that humans must have around 100,000 genes; some estimates went as high as 150,000.
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All human beings are, in fact, born with dozens of mutations their parents lacked, and a few of those mutations could well be lethal if we didn't have two copies of every gene, so one can pick up the slack if the other malfunctions.
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Whereas recessive traits require two bad copies of a gene to become noticeable, a dominant trait expresses itself no matter what the other copy does. A benign example of dominance: If you inherit one gene for sticky wet earwax and one gene for dry earwax, the sticky earwax gene wins out every time.
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The density of space junk peaks around 620 miles up, in the middle of so-called low-Earth orbit. That's bad, because many weather, scientific, and reconnaissance satellites circle in various low-Earth orbits.
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No element gets people telling crazy stories like mercury does. People have told me tales about pharmacists waxing floors with mercury, mothers rubbing it into babies' skin to kill germs, and 10-year-olds coating dimes in it to make them shine, then blithely carrying them around in their pockets.
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Most people who have encountered mercury have done so after breaking a mercury thermometer. And many of us who saw the liquid balls of mercury scatter across a floor or countertop considered the element the most beautiful on the periodic table.
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Every glass thermometer has subtle variations in the size and shape of the bulb at the bottom and the capillary tube inside, as well as variations in the width of gradations on the side. The compounded effect of these uncertainties is that each thermometer reads temperature slightly differently.
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On a submicro scale, pure diamond is billions of billions of carbon atoms bonded to one another. If you shrunk yourself down and stood inside the diamond, you'd see nothing but carbon in a perfect pattern in every direction.
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The price of diamonds can vary greatly depending on size, cut, color, and other factors, including whether they have a history. But because of the rarity of blue boron diamonds, they often fetch more money than gems of similar quality.
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Carbon's eastern neighbor on the table, nitrogen, dresses up diamonds in pinks, yellows, oranges, and brownish tints known romantically as 'champagne.'
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Atoms of Element 118 fill an outer shell with electrons, creating a special type of element called a noble gas. Noble gases are natural turning points on the table, ending one row and pointing to the next.
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Everywhere in the universe, the periodic table has the same basic structure. Even if an alien civilization's table weren't plotted out in the castle-with-turrets shape we humans favor, their spiral or pyramidal or whatever-shaped periodic table would naturally pause after 118 elements.
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Atoms consist of a positive nucleus and negative electrons flying around outside it. Electrons closest to the nucleus feel a strong negative-on-positive tug, and the bigger atoms get, the bigger the tug. In really big atoms, electrons whip around at speeds close to the speed of light.
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Polonium is, frankly, pretty useless, and no country in the world except Russia bothered to refine it by the late 2000s.
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Despite the disreputable company it keeps, bismuth is harmless. In fact, it's medicinal: Doctors prescribe it to soothe ulcers, and it's the 'bis' in hot-pink Pepto-Bismol. Overall, it seems like the most out-of-place element on the periodic table, a gentleman among scoundrels.
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When it comes to the periodic table, the United States really blew its chance to make a name for itself. If you look over a map of all the elements named for cities, states, countries, and continents, it's not surprising that European locales dominate the map.
401
After about 1940, scientists generally stopped looking for elements in nature. Instead, they had to create them by smashing smaller atoms together.
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Entrepreneurs in the United States and Europe finally figured out how to separate aluminum from minerals cheaply and also how to produce it on an industrial scale.
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Radium, discovered by Marie and Pierre Curie in 1898, was especially popular: the 'it' element of its day. Radium glows an eerie blue-green in the dark, giving off light for years without any apparent power source. People had never seen anything like it.
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Your body thinks radium is a great thing to pack into bone - where it kills some cells outright and scrambles the DNA of others, causing problems like cancer.
405
If studying the periodic table taught me nothing else, it's that the credulity of human beings for periodic table panaceas is pretty much boundless.
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The body tends to treat elements in the same column of the periodic table as equivalents.
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Many different elements can form isomers, but only a few elements on the periodic table, like hafnium, can form isomers that last more than fractions of a second - and might therefore be turned into weapons.
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Some scientists claim - although these claims are contentious - that they can form deadly isomers with simple X-rays and that hafnium can multiply the power of these X-rays to an astounding degree, converting them into gamma rays up to 250 times more potent than the X-rays.
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Among physicists and chemists, cold fusion - nuclear fusion at close to room temperature - enjoys a reputation about on par with creationism.
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There are a few elements - especially platinum and palladium - that have the amazing ability to absorb up to 900 times their own volume in hydrogen gas. To get a sense of the scale there, that's roughly equivalent to a 250-pound man swallowing something the size of a dozen African bull elephants and not gaining an inch on his waistline.
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Something funny certainly happens when palladium and platinum come into contact with hydrogen gas; it's one of the great mysteries still waiting to be solved on the periodic table. But it's quite a leap from 'something funny' to cold fusion.
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Unlike uranium, plutonium was created in an American lab in 1940, but scientists soon realized that it could produce even wilder chain reactions and even bigger explosions. In fact, fearing another country would create it, too, the American government went to great lengths to keep even the existence of plutonium a secret.
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The noble gases, which reside on the East Coast of the periodic table, are its aristocrats - detached and aloof, never bothering to interact with the rabble of common elements that make up the vast majority of the world.
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Scientists didn't discover the noble gas helium - the second most common element in the universe - on Earth until 1895. And they thought it existed in minute quantities only, until miners found a huge underground cache in Kansas in 1903.
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One theme I ran into over and over while writing about the periodic table was the future of energy and the question of which element or elements will replace carbon as king.
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Scientists have continued to tinker with different elements and have learned new ways to store and deliver energy.
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Lithium makes a fine battery because it's a scarily reactive metal. Pure lithium ignites on contact if it touches water - a flake of it would sizzle and fry on the water-rich cells of your skin.
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Over the years, humans have managed to incorporate nearly every element, light and weighty, common and obscure, into our daily lives. And given how small atoms are and how many of them there are all around us, it's almost certain that your body has at least brushed against an atom of every single natural element on the periodic table.
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Most stars just fuse hydrogen into helium, but larger stars can fuse helium into other elements. Still larger stars, in turn, fuse those elements into slightly bigger ones, and so on.
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