« Older Entries

Anesthesia

In 1853 the Queen’s personal physician, Dr. John Snow dripped an ounce of chloroform on a handkerchief which was then held next to the royal mouth as Prince Leopold was delivered.  Her Majesty was very happy with the experience and endorsed the use of chloroform.  Many women followed suit, sometimes even naming their newborn children “Anesthesia.”

How Chocolate Won the War

Screen Shot 2016-12-16 at 10.53.30 AM

The Right Chemistry: The thermite reaction can be used in tools or weapons

grenadesThe place was Edinburgh, Scotland. The occasion, the Edinburgh Science Festival. There were a number of captivating presentations, but my biggest thrill came from looking out the hotel window. A light rail track was being constructed just outside and the workers were busy welding. My eyes popped when I saw what they were doing. I was looking at a live thermite reaction! I had talked about this reaction in class on numerous occasions and marvelled on it in videos, but had always deemed it too dangerous to perform.

A chemical reaction that produces heat is said to be “exothermic.” The most common example would be the combustion of a fuel. Light a candle and you can feel the heat that is produced. The hottest part of a flame, where the colour is a light blue, can reach a temperature of about 1400 degrees Celsius. But that is a low temperature compared to the 2500 degrees produced by the “thermite” reaction between aluminum and iron oxide. Essentially, this reaction involves the transfer of oxygen from the iron oxide to aluminum to yield aluminum oxide and metallic iron. At this high temperature, the iron is in its molten form and sets fire to any combustible material in its path, making the thermite reaction ideal for use not only in welding, but also in incendiary bombs and grenades.

Back in 1893, German chemist Hans Goldschmidt was looking for a way to produce pure metals from their ores. The classic method for extracting iron relies on heating iron oxide ore with carbon. The carbon is converted to carbon dioxide as it strips oxygen from the iron, leaving behind metallic iron. Some unreacted carbon, however, tends to contaminate the iron. Goldschmidt was looking for a way to produce iron without the use of carbon and hit upon the reaction of iron oxide with aluminum. He was impressed by the remarkable amount of heat produced and suggested that the reaction he had discovered could be used for welding. In 1899, the thermite reaction was put to a commercial use for the first time, welding tram tracks in the city of Essen.

It didn’t take long for the military to realize the potential of this extreme exothermic reaction in warfare. In 1915, the Germans terrorized England by using Zeppelins to drop incendiary bombs based on the thermite reaction. By the Second World War, the battle was on not only between Allied and German armed forces, but also between their scientists and engineers who sought to produce more effective incendiary devices. The Germans came up with the “Elektron” bomb, named after Elektron, an alloy composed of 86 per cent magnesium, 13 per cent aluminum and 1 per cent copper that was used for the casing of the bomb.

This alloy burns with a very hot flame, but requires a high temperature for ignition. The thermite reaction was up to the task. When an Elektron bomb hit the ground, a small percussion charge of gunpowder ignited a priming mixture of finely powdered magnesium and barium peroxide. This reaction produced the heat needed to ignite the thermite mix of aluminum and iron oxide, which in turn ignited the highly combustible casing. The Allies developed similar types of bombs resulting in the most destructive air raid in history, which was not Hiroshima or Nagasaki, but the firebomb raid on Tokyo in March 1945. An Allied bombing of Dresden the same year with incendiary bombs virtually destroyed the whole city. During the Second World War, the Allies dropped some 30 million 4-pound thermite bombs on Germany and another 10 million on Japan.

Thermite hand grenades were also used during the war to disable artillery pieces without the need for an explosive charge, very useful when silence was necessary to an operation. This involved inserting a thermite grenade into the breech of a weapon and then quickly closing it. The great heat produced by the thermite reaction welded the breech shut and made loading the weapon impossible. Alternatively, a thermite grenade was discharged inside the barrel of an artillery piece making it useless.

During the Vietnam war, thermite grenades found a different use. From the start of hostilities, putting a crimp into the enemy’s food supply was part of the U.S. military strategy. Since rice was a staple for the Viet Cong, destroying rice paddies was a primary goal. At first, attempts were made to blow up rice stocks and destroy paddies with hand grenades and mortars, but this proved to be maddeningly difficult. The next idea was to burn the rice paddies with thermite grenades. All this did was scatter the rice grains, which could then still be harvested. Another approach was needed.

Enter “Agent Blue,” an arsenic-based herbicide, unrelated chemically to the more infamous Agent Orange. Agent Blue affects plants by causing them to dry out, and as rice is highly dependent on water, spraying Agent Blue on rice paddies can destroy an entire field and leave it unsuitable for further planting. The U.S. used some 20 million gallons of Agent Blue during the Vietnam war, destroying thousands of acres of agricultural fields and defoliating wooded areas that the Viet Cong used to ambush American troops.

Recently, the thermite reaction made the news in a different context. Conspiracy theorists purport that it was thermite explosives planted inside the World Trade Center that brought down the twin towers in a CIA coordinated plot. They also maintain that the moon landing was faked and that the U.S. government is hiding the bodies of aliens. Some also claim that the rise of Donald Trump was engineered by a Democratic conspiracy and that on the verge of being elected he will announce “fooled you.” Wouldn’t that be something? It would trump the thermite reaction for heat generated.

Dr. Joe Schwarcz

Antimony!

antimonyPicture this. You swallow a little pill, wait until it irritates your intestines enough to expel its contents and then hunt through the expelled excrement to retrieve the pill. Why? So you can use it next time to get rid of the bad humours in your body that are making you sick. How can a pill survive passage through the digestive tract? It can, if it is made of metal, in this case, antimony. Now, don’t go asking the pharmacist for antimony pills. The scenario just described isn’t current, it was plucked out of the Middle Ages when the cure for disease was to expel “bad humours” from the body. Actually, that was not unlike the current craze of expelling unnamed toxins from the body with a variety of “cleanses,” many of which have a laxative effect.

Hopefully nobody today would be silly enough to use antimony or its compounds, because here we are talking about real toxicity. Of course they didn’t realize that in the Middle Ages; all they knew was that antimony was pretty good at evacuating the body. And not only through the rear portals. One method involved drinking wine that had been left standing overnight in a cup made of antimony. This resulted in the antimony reacting with tartaric acid in the wine to form antimony tartrate, a compound that induces vomiting. The idea of purging the body to treat illness persisted into the late stages of the 18th century. When Mozart came down with a mysterious illness, he was treated with “tartar emetic,” as antimony tartrate was commonly called. What ailment he suffered from isn’t clear, but he died within two weeks. His symptoms of intense vomiting, fever, swollen abdomen and swollen limbs are consistent with antimony poisoning. Of course, we cannot prove that antimony was responsible for Mozart’s death, he also suffered from rheumatic fever since childhood, a condition that may have led to his demise at a young age.

Mozart had always been sickly and it is well known that he had been often treated with antimony compounds by his physicians and that he even dosed himself when he didn’t feel well. It is interesting that Mozart actually believed he was being poisoned, but not by himself. He thought his musical rival Antonio Salieri was trying to do him in. Although the famous movie “Amadeus” alludes to this possibility, historical facts do not corroborate the poisoning story. Contrary to the portrayal, Salieri did not confess at the end of his life to having tried to kill Mozart.

Back in the 1990s a volatile compound of antimony known as stibine (SbH3) was accused of being responsible for crib death. The theory was that it was produced from antimony oxide added as a flame retardant to polyvinylchloride sheets. A fungus found in mattresses supposedly made this conversion possible, at least under laboratory conditions. The theory has now been dismissed because neither the fungus, nor levels of antimony in babies’ blood could be correlated with crib death.

More recently Greenpeace created a stir with a booklet entitled “A Little Story About The Monsters In Your Closet.” What sort of “monsters?” The subtitle brings them out of the closet: “Study finds hazardous chemicals in children’s clothing.” Yup, the monsters are chemicals. One that the Greenpeace study detected was antimony trioxide, present in all fabrics that have polyester as a component. No great surprise here since antimony trioxide is used as a catalyst in the production of polyester as well as a flame retardant. And it is true that antimony trioxide can be described as presenting a hazard. But hazard is not the same as risk.

Hazard is the innate potential of a substance to cause harm without taking into account extent or type of exposure. Inhalation of antimony compounds in an occupational setting can be a problem, and it is correct that antimony trioxide has been classified as “suspected of causing cancer via inhalation.” But this is not relevant for the trace amounts found in fabrics. Here the issue would be migration out of the fabric and subsequent absorption. This has been extensively investigated and the amounts that are encountered are well below the established migration limits. The same applies to the trace amounts that leach out of the polyester bottles that are widely used for water and other beverages. Concentrations are less than the 5 parts per billion safety limit.

Antimony does not occur in nature in its metallic form, so where did Middle Age physicians get it? Like most metals, antimony has to be smelted from its ore, in this case antimony sulfide, also known as stibnite, a substance that has been known for thousands of years. Jezebel, the Biblical temptress is said to have used it to darken her eyebrows and stibnite was the main ingredient in “kohl” used by ancient Egyptian women in a type of mascara. Exactly who figured out that heating antimony sulfide converts it to antimony oxide, which yields metallic antimony when fired with carbon, is unknown, but if you visit the Louvre, you can see a 5000 year old vase that is made of almost pure antimony.

Today, neither metallic antimony nor its compounds have a medical use, although up to the 1970s, antimony compounds were used to treat parasitic infections like schistosomiasis. These preparations did kill the parasites, but sometimes they also dispatched the patient. Up to the early twentieth century, tartar emetic was used as a remedy, albeit an ineffective one, for alcohol abuse. The New England Journal of Medicine once reported a case of a man whose wife tried to cure him of his alcoholic habit by secretly putting tartar emetic into his orange juice. The result was a trip to the hospital with chest pains and liver toxicity. Two years later the man reported complete abstinence from alcohol. Seems antimony had taught him a lesson.

Joe Schwarcz PhD

National Bunsen Burner Day

bunsen burnerMarch 31st was National Bunsen Burner Day. Bunsen (1811-1899) should be remembered. After all, the “Bunsen Burner” is a typical symbol of chemistry. But there is more to Bunsen than just a burner.

Laboratory workers had long been plagued by sooty, hard-to-control flames and Bunsen of course knew that oxygen was necessary for combustion and that soot was the product of incomplete combustion. He therefore concluded that the secret to a clean flame lay in mixing the combustible gas with air in just the right proportion.

The prototype Bunsen burner consisted of a metal tube with strategically drilled holes through which air could enter and mix with the combustible gas flowing through the tube. A sliding metal cover allowed the operator to vary the number of open holes and thus control the character of the flame. Bunsen, however, never patented his invention. He did not believe that scientists should profit financially from their work; research was to be done for its own sake.
Why was Bunsen so interested in developing a clean flame? Because he had a passion for studying the diverse brilliant colors produced by sprinkling various substances into a fire. He had noted that throwing sodium chloride (ordinary salt) into a flame always resulted in a bright orange-yellow glow. The same color appeared if sodium bromide, or indeed any compound of sodium was cast into the flame. Other elements also produced characteristic colors. In fact Bunsen discovered the existence of the elements rubidium and cesium through the colors they produced.

Over a hundred years earlier, Newton had shown how a prism can be used to separate white light into the colors of the rainbow. Bunsen now applied this principle to separate the colors of a flame into their individual components. The spectroscope, an instrument he developed together with the physicist Kirchoff, allowed unknown substances to be identified purely by the colors they produced when heated in the flame of a Bunsen burner.

So, who cares what colors are produced in a flame? Well, just think of the glorious colors of fireworks. Or the bright red strontium flame of an emergency roadside flare. Or the yellow glow of a sodium vapor highway light. The original studies that led to these applications were painstakingly carried out by Robert Bunsen.
After having long toiled with flames and spectroscopes in the laboratory, the great man spent years writing up his work for publication. The day the manuscript was finished, he left it on his desk and went out to celebrate. When he returned, Bunsen was horrified to see a smoldering pile of ashes where his treasured treatise had been.

A flask filled with water had been next to the papers and had acted as a magnifying glass, focussing the sun’s rays and igniting the manuscript. A lesser man would have surrendered to fate at this point. But Bunsen, even at an advanced age, doggedly repeated the work and eventually published the results of his spectroscopic research so that all the world finally became aware of his burner.

 

Joe Schwarcz PhD

Golden Marketing

golden marketingMarketing these days is often based not on what is in a product, but rather on what it doesn’t contain. Labels scream no cholesterol, no trans fats, no gluten, no BPA, no phthalates, no parabens and the ultimate absurdity, no chemicals. Smirnoff vodka, however, is going against this trend with the introduction of Smirnoff Gold that has a hint of cinnamon flavouring and floating flakes of pure gold. The thin slivers of gold stay dispersed through the beverage, give the product a luxurious image and draw attention to the bottle on the shelf. No health claim of any kind is made but Smirnoff promises that the cinnamon flavor is all the better due to the edible gold leaf. That is highly questionable since gold has no taste and is essentially insoluble in alcohol. It adds glitter but nothing else.

No worry about consuming the gold though, it is indeed edible and has been eaten since the days of the ancient  Egyptians when it was thought to purify the body, mind and spirit. In Elizabethan England, the wealthy served meals decorated with gold leaf, and in Italy desserts decorated with gold were supposed to ward off heart disease. Alchemists searched for elixirs made of drinkable gold that would supposedly restore youth and rid the body of disease. The hope was that since gold was the eternal metal, not subject to aging in any fashion, it would transfer its anti-aging properties to whoever consumed it. They weren’t totally on the wrong track because in the twentieth century some compounds of gold were shown to have an effect on easing the pain of arthritis. Drinking Smirnoff Gold vodka may ease the pain of arthritis, but not because of the presence of any gold. Alcohol can distract from pain.

This is not the first alcoholic beverage to feature the inclusion of gold. Danziger Goldwasser, a German root and herbal liqueur which has been produced since at least 1598 features gold flakes, as does Goldschläger, a Swiss cinnamon schnapps. The name comes from the German for “gold beater,” referring to the profession of beating bars of gold into micrometer-thin sheets. There is no truth to the rumour that the gold flakes are added to the beverage to make tiny cuts in the throat for quicker absorption of alcohol. The flakes are way too thin to have any such effect. So you don’t have to worry about eating the world’s most expensive pizza at Margo’s Pizzeria in Malta where a pie decorated with gold goes for about $400 U.S.

But if you really want to go on a spending spree, seek out the 666 Burger food truck in New York where for $666 you can purchase a foie gras-stuffed Kobe patty covered in Gruyere cheese that’s been melted with champagne steam and topped with lobster, truffles, caviar, and a BBQ sauce made with Kopi Luwak coffee beans that have been pooped out the Asian palm civet. The whole thing is then served in a gold-leaf wrapper. Basically it is a sarcastic comment on the super expensive burgers available in some restaurants. So far people are not lining up for the golden burger, but the food truck sure got some golden publicity.

Joe Schwarcz PhD

It won’t grow hair on your palms or make you blind…

Happy Valentine's DayValentine’s Day is here and everyone is talking about love!  But for many people in our modern society, a fulfilling love life also involves an active and healthy sex life.  Although we have come a long way in the liberation of our minds and bodies from cultural taboos and socially imposed restrictions on our sexual attitudes and activities, we still carry with us many remnants from the past, from times when natural aspects of sexuality were frowned upon, discouraged or even demonized.  Despite our recent sexual revolution, for many of us, the topics of sex and its idiosyncrasies are still difficult ones to discuss openly because of personal embarrassment or ignorance.  It turns out that if we look at our sexual activity through a scientific lens that we may be able to better understand and even embrace our sexual enigmas.

The topic of masturbation, for example, is one of the most difficult ones for many to discuss… but it may actually play an important role in our sexual behaviour and have dramatic effects on male fertility.

The classic sociological explanation for why males (in particular) of most mammal species engage so readily and frequently in acts of masturbation is that it is just another form of playing or practice.  Playing is a common feature of juvenile mammalian life that may act as a safe means to practice the skills that will become necessary upon becoming an adult.

In this sense, masturbation may be seen as a means to hone our skills in preparation for sex, should the opportunity arise later. Additionally, masturbation may also be a by-product of the pleasure associated with the act, which itself is an evolved feature to promote engaging in sex as an essential component of propagating the species.

Whereas these preceding explanations may certainly apply, studies of a biological nature point out that masturbation also plays an important role in maintaining male fertility by ensuring that each sperm ejected during sex has the highest potential for fertilizing the available egg.

To set the scene for understanding the journey and fate of each individual sperm cell, a little note about testicular anatomy may be in order.  Human testes are divided up into several small compartments, within which are up to 800 tightly coiled seminiferous tubules that house the sperm cells as they are produced.  Each tubule is so tightly packed that if they were all laid out end to end, every man would have over one and a half kilometers of sperm ducts in their scrotal sac.  That’s a lot!

As the sperm are produced within the base of the tubules, they are pushed outward towards the ejaculatory duct, where they sit and wait in the epididymis for 2 weeks or so, while they fully mature to become fertile.  This process is continuous, producing hundreds of millions of sperm per day and leading to ejaculates that may contain upwards of 400 million sperm.  That’s an impressive assembly line, and it must make the epididymis a crowded place, as anyone who has seen Woody Allen’s film Everything You Wanted to Know About Sex can testify!

Once sperm are mature, however, their lifespan is quite limited, on the order of a few days to a week or so.  Given that the production of sperm originates in the testes and pushes the older sperm to the outside, after about a week those sperm waiting to be part of the next ejaculate load may actually be infertile and useless to the reproductive aspects of sexual intercourse.

It is obvious then that males that do engage in semi-regular bouts of masturbation, may actually be cleaning out the epididymis of older, less-fertile sperm and ensuring that each ejaculate contains only the most viable and fertile ones.  This would be an important evolutionary adaptation that favours successful reproduction, rather than shooting blanks, as would be the case in those males who allow a build-up and long-term storage of sperm.  Interestingly, even among males who do not regularly masturbate, their bodies have a back-up plan that helps to maintain sperm viability by spontaneously expelling old loads during sleep, in a process commonly known as nocturnal emissions.

It seems, therefore, that our bodies and minds may have been primed over evolutionary time to include masturbation into our regular sexual repertoire because of the many fertility-related advantages that it may bring to our species.

Another sexual enigma that has fueled much intrigue and speculation surrounding human sexuality relates to the role of the female orgasm. Although it is clearly associated with female sensual pleasure and may act to increase their willingness to engage in sex, thereby promoting the propagation of our species, there is strong evidence that it may also play a role in enhancing female fertility.

Scientific studies that have been capable of visualizing the internal muscular contractions during female orgasm have noted that it may actually act as a uterine-pump, actively drawing up sperm deposited into the vagina and directing it towards the uterine or Fallopian tubes, where fertilization takes place.  As such, although orgasms in women are not required to ensure fertilization during sex, they certainly act to make it more likely.  In this way, the female orgasm can be seen as another evolutionary trait in our complex range of sexual behaviours that promotes successful reproduction in our species and even has an effect on who’s fathering whom, because those men that can induce orgasms will be more successful at fertilizing eggs in the process.

Once again, evolution has primed our species to be able to make the most of our sexual encounters in such a way that a viable and successful reproduction is the most likely outcome.  Wow, being sexy is smart!

So, on this day of Love and all of its parameters, let’s not forget that the behaviours that we associate with our sexuality, mating and reproduction are all important features of being human and that these are all good reasons to celebrate with your partner (or alone) on this Valentines Day, as well as every other day of the year!

Dr. Adam Brown PhD

Love it or Hate it

cilantroWhen it comes to food, everyone has likes and dislikes. Chocolate generally gets favourable comments, spinach less so. But no flavour seems to elicit the degree of polarizing comments as that of cilantro. There are websites and Facebook groups dedicated to demonizing cilantro, likening its aroma to soap or curiously, to dead bugs.

The seeds of the cilantro plant are known as coriander and are even mentioned in the book of Exodus. Archeologists found some in King Tutankhamen’s tomb, perhaps placed there with hopes of adding some spice to the afterlife. The ancient Chinese believed there would be no need to worry about the afterlife if you consumed cilantro because the herb conferred immortality. Hippocrates used it as medicine and even today some people ascribe health benefits to the herb based on its content of antioxidants, anti-bacterial compounds and minerals. These, though, are not unique to cilantro, all plants contain varying quantities of these substances.

Another supposed benefit is cilantro’s ability to chelate heavy metals. The term “chelate” comes from the Greek meaning “claw” and refers to compounds that have the ability to remove harmful metal ions from solution by gripping them like a claw. Some bloggers even push cilantro as an ingredient in a “detox” salad, claiming it rids the body of heavy metals. As usual, there is a kernel of truth to the claim, but that kernel is inflated with nonsense until it pops.

A few studies have shown that cilantro leaves can produce a chelating effect in water spiked with heavy metals and that cilantro can reduce absorption of lead when food tainted with it is fed to mice. But these effects are light years from a salad with cilantro accomplishing any sort of heavy metal “detoxing” in people. Such a claim would require a demonstration of there being a heavy metal problem in the first place and its reduction with cilantro. A PubMed search for “cilantro detox” yields zero entries. Similarly, there is no basis to some food faddists’ claim that “cilantro can reduce water weight, is a cancer fighter and can improve memory with its brain protecting vitamins and minerals.”

While the scientific literature provides no evidence for health benefits, it does provide clues when it comes to cilantro’s polarizing flavour. What we refer to as flavour is the sensation triggered when molecules in food encounter receptors on our taste buds and in our nasal passage. Indeed, scent is an integral part of the sensation as evidenced by cilantro haters not being bothered if they consume the herb while holding their nose.

Some forty compounds have been isolated from cilantro including a number in the aldehyde family that are mainly responsible for the aroma and taste. The composition of the seeds is somewhat different, having linalool, also found in lavender and cannabis, as a major component. It has a pleasant floral scent accounting for its use in cleaning agents, detergents and shampoos. When inhaled it can reduce stress. At least in lab rats. Rats that inhaled linalool saw a reduction in the elevated levels of white blood cells induced by stress.

It is the aldehydes in cilantro that cause some people to liken the scent to soaps and lotions because these compounds are indeed found in those products. But why only some people? One theory is that the cilantrophobes are “supertasters” and can taste compounds that others can’t. Supertasters do exist, but they react to very specific bitter compounds such as propylthiouracil, while most people taste nothing. However, there are no such compounds in cilantro and “supertasters” are no more likely to be cilantro haters than anyone else.

It seems, though, that people ho abhor cilantro may have some sort of genetic connection, if we go by an interesting study carried out by Dr. Charles Wysocki of the Monell Chemical Senses Center in Philadelphia. Taking advantage of the annual twins festival in Twinsburg, Ohio, Wysocki had identical and fraternal twins rate the scent of chopped cilantro. There were definitely lovers and haters, with identical twins almost always agreeing with their sibling, which was not the case for fraternal twins. Experiments at Monell have also separated the components of cilantro using gas chromatography and showed that while everyone can smell the “soapy” aldehydes, cilantro haters cannot smell the compounds that make the herb so attractive to its fans.

Interestingly, there is also an ethnocultural connection. A study at the University of Toronto surveyed 1639 young adults and had them rate their preference for cilantro on a 9 point scale. East Asians were the most likely to dislike cilantro with roughly 21% expressing their distaste. Caucasians were not far behind at 17%. Only 14% of those of African descent disliked the taste, followed by South Asians at 7%, Hispanics at 4% and Middle Eastern subjects at 3%. These stats roughly parallel the use of cilantro in the cuisine of these areas suggesting that there is a connection between liking cilantro and frequency of exposure.

While cilantro’s enemies would rather stick rusty needles into their eyeballs than eat the fresh herb, they normally don’t object to cilantro in cooked foods such as pesto. That’s because the herb’s flavor changes as the volatile aldehydes escape into the air when it is crushed, cooked or pureed. Cilantro fans of course crave fresh cilantro and when cooking add the herb at the end stage. As for me, I’m with Julia Child on this one. Back in 2002 she told Larry King in an interview that if she found cilantro in a dish she was served she would pick it out and throw it on the floor. I recognize, though, that there are people who would jump to catch it before it hit the ground because they just love the smell and taste of this herb that has pleased some and irritated others since biblical times.

Joe Schwarcz PhD

« Older Entries
Blog authors are solely responsible for the content of the blogs listed in the directory. Neither the content of these blogs, nor the links to other web sites, are screened, approved, reviewed or endorsed by McGill University. The text and other material on these blogs are the opinion of the specific author and are not statements of advice, opinion, or information of McGill.