March 21, 2014

Byzantium’s secret weapon

Filed under: Europe, History — Tags: , , , — Nicholas Russon @ 07:50

Military History Now had a guest post from Κonstantinos Karatolios talking about the Byzantine secret weapon known as “Greek Fire”:

The thousand-year Byzantine Empire could not have survived through the centuries without its powerful military. But Constantinople’s mighty army and navy didn’t just keep enemies at bay, they also helped it to expand into new territories and ultimately dominate the whole of the Mediterranean for hundreds of years. Of course, while the Byzantines’ stunning battlefield success was in part a by-product of military knowledge inherited from the old Roman Empire, it was also born out of new tactics and weaponry. One example of this is Greek fire. Also known as thalassion pyr, skeyaston pyr and medikon elaion, this incendiary liquid, which could be squirted or hurled into the ranks of an enemy, was perhaps the most fearsome of all of the empire’s armaments. Its use, whether on land or sea, verges on legend and yet almost all we know about Greek fire remains clouded in mystery. We are sure of one thing however — it was used with devastating effect throughout the whole course of the Byzantine Empire.

Here are nine little known facts about Greek fire.

I think there’s a typo in the list, as it mentions the first recorded use of the weapon by Anastasios I in 541, which was actually the middle of the reign of Justinian I. Anastasios I reigned from 491 to 518.

November 27, 2013

OMG! There are scary-sounding chemicals in your Thanksgiving Dinner!

Filed under: Environment, Health, Media — Tags: , , — Nicholas Russon @ 09:23

Our American friends are about to celebrate their (weirdly late) Thanksgiving this week, so junk science food scares are also making another annual appearance. Angela Logomasini explains why you can safely ignore most of the advice you may receive about food safety this Thanksgiving:

Toxic chemicals lurk in the “typical” Thanksgiving meal, warns a green activist website. Eat organic, avoid canned food, and you might be okay, according to their advice. Fortunately, there’s no need to buy this line. In fact, the trace levels of man-made chemicals found in these foods warrant no concern and are no different from trace chemicals that appear in food naturally.

The American Council on Science and Health (ACSH) illustrates this reality best with their Holiday Dinner Menu, which outlines all the “toxic” chemicals found naturally in food. The point is, at such low levels, both the man-made and naturally occurring chemicals pose little risk. This year the ACSH puts the issue in perspective explaining:

    Toxicologists have confirmed that food naturally contains a myriad of chemicals traditionally thought of as “poisons.” Potatoes contain solanine, arsenic, and chaconine. Lima beans contain hydrogen cyanide, a classic suicide substance. Carrots contain carototoxin, a nerve poison. And nutmeg, black pepper, and carrots all contain the hallucinogenic compound myristicin. Moreover, all chemicals, whether natural or synthetic, are potential toxicants at high doses but are perfectly safe when consumed in low doses.”

Typically, these kinds of food safety scares depend on using unfamiliar scientific names of various chemicals, knowing that most peoples’ memories of high school science have long since faded away. Anything “safe” has an ordinary name, while anything “toxic” goes by a tongue-twisting science-y name that conceals far more than it reveals to non-scientists. Remember how many times the dangers of dihydrogen monoxide (DHMO) have been used to whip up support for petitions to ban the stuff (see the Material Safety Data Sheet (pdf) for it). Dihydrogen monoxide is a science-y way of describing a molecule with two hydrogen atoms and one oxygen atom … it’s another name for water, but it sounds so much more ominous that way, doesn’t it?

June 21, 2013

The healing powers of silver

Filed under: Health, Science — Tags: , , , — Nicholas Russon @ 09:01

In The Economist, some new ideas about silver:

Silver has long been known as more than bling. In the fifth century BC Hippocrates noted its ability to preserve food and water. In the late 19th century silver-nitrate eye drops were administered to newborns to prevent conjunctivitis (though this remedy has since been replaced with an antibiotic). Today silver is routinely found in wound dressings and catheters to treat or prevent infections. Yet, despite its widespread use, the source of silver’s antibacterial properties has remained shrouded in mystery.

Now Jose Morones-Ramirez, from Boston University, and colleagues think they may have cracked it. As they report in Science Translational Medicine, silver fights bacteria in a number of ways.

First, silver ions (as atoms stripped of some of their electrons are known) help, through a process known as the Fenton reaction, to convert hydrogen peroxide into molecules called hydroxyl radicals. Radicals are unstable and readily react with cellular components, damaging them. Indeed, an excess is thought to contribute to ageing-related illnesses in humans. However, the researchers found, concentrations of silver ions low enough to leave human cells unscathed nonetheless appear to wreak havoc on bacterial ones.

Using a dye that glows in the presence of hydroxyl radical, Dr Morones-Ramirez treated the bacterium Escherichia coli with silver nitrate (a source of silver ions). The E. coli glowed, and then promptly bit the dust. But when the bacteria were first bathed in a chemical which mops up the hydroxyl radicals, they survived. This points to silver’s effect on the production of hydroxide radicals as the explanation.

April 4, 2013

April 1st meets scientific illiteracy in Florida

Filed under: Humour, Media, USA — Tags: , , , — Nicholas Russon @ 00:01

Did you know that there is dihydrogen monoxide streaming out of the water taps in Fort Myers, Florida? Apparently a lot of radio listeners thought this was a very bad thing:

Florida country radio morning-show hosts Val St. John and Scott Fish are currently serving indefinite suspensions and possibly worse over a successful April Fools’ Day prank. They told their listeners that “dihydrogen monoxide” was coming out of the taps throughout the Fort Myers area. Dihydrogen monoxide is water.

The popular deejays are mainly in all this trouble (potentially of a felony level) because their listeners panicked so much — about the molecular makeup of their drinking water, however unwittingly — that Lee County utility officials had to issue a county-wide statement calming the fears of chemistry challenged Floridians.

February 15, 2013

A useful bit of perspective over Whinnygate

Filed under: Europe, Health — Tags: , , — Nicholas Russon @ 11:35

It’s reasonable to be concerned that your hamburger may once have raced in the Grand National, but worries about chemical contamination from the horse meat are almost certainly overblown. In fact, your health might be more at risk from the burger itself:

There is reasonable public outrage at possible criminal conspiracies to adulterate meat products with horsemeat, and additional concerns raised about the presence of the anti-inflammatory known as bute.

While not in any way questioning this concern about adulteration with a chemical compound, it is helpful to get a sense of magnitude. When bute was given as a human medicine, it was reported to be associated with a serious adverse reaction in 1 in 30,000 (over a whole course of treatment), but at a dose giving concentrations at least 4,000 times that arising from eating a diet of horse meat – see the excellent information from the Science Media Centre

So making all sorts of heroic assumptions about there being a linear-no-threshold response, we might very roughly assign a pro-rata risk of a serious event as 1 in 100,000,000 per burger.

January 10, 2013

QotD: The mild, quiet, unassuming world of high-nitrogen compounds

Filed under: Humour, Quotations, Science — Tags: , — Nicholas Russon @ 00:02

When we last checked in with the Klapötke lab at Münich, it was to highlight their accomplishments in the field of nitrotetrazole oxides. Never forget, the biggest accomplishment in such work is not blowing out the lab windows. We’re talking high-nitrogen compounds here (a specialty of Klapötke’s group), and the question is not whether such things are going to be explosive hazards. (That’s been settled by their empirical formulas, which generally look like typographical errors). The question is whether you’re going to be able to get a long enough look at the material before it realizes its dream of turning into an expanding cloud of hot nitrogen gas.

It’s time for another dispatch from the land of spiderweb-cracked blast shields and “Oh well, I never liked that fume hood, anyway”. Today we have a fine compound from this line of work, part of a series derived from N-amino azidotetrazole. The reasonable response to that statement is “Now hold it right there”, because most chemists will take one look at that name and start making get-it-away-from-me gestures. I’m one of them. To me, that structure is a flashing red warning sign on a dead-end road, but then, I suffer from a lack of vision in these matters.

But remember, N-amino azidotetrazole (I can’t even type that name without wincing) is the starting material for the work I’m talking about today. It’s a base camp, familiar territory, merely a jumping-off point in the quest for still more energetic compounds. The most alarming of them has two carbons, fourteen nitrogens, and no hydrogens at all, a formula that even Klapötke himself, who clearly has refined sensibilities when it comes to hellishly unstable chemicals, calls “exciting”. Trust me, you don’t want to be around when someone who works with azidotetrazoles comes across something “exciting”.

Derek Lowe, “Things I Won’t Work With: Azidoazide Azides, More Or Less”, In the Pipeline, 2013-01-09

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