Why are peanut allergies suddenly becoming more common in North America than elsewhere in the world?Posted on December 1st, 2010 No comments
Nobody gave the answer I was looking for. The answer from @jchaager is probably at least partly correct: “Parents are raising their kids in a bubble and preventing early exposure to allergens that would build up their immunity.”
The “overprotective parents” hypothesis (or “hygiene hypothesis”) of increase of allergies is probably at least partly true, but doesn’t lend itself to experimental verification. What parent would agree to raise their child in “dirty” conditions for experimental purposes? Nevertheless, there is some anecdotal support of the idea. On the other hand, there is also experimental support of the idea that exposing a child to an allergen too early may trigger an allergy rather than boost their tolerance.
Anyway, there is a biochemical and cultural cause that is hypothesized as a reason for increased peanut allergies in North America. In North America, most peanuts are roasted, rather than boiled. Boiling, as done in most of the rest of the world, neutralizes some allergens in peanuts.
One of the main allergens in peanuts is “Ara h2,” which inhibits protein digestion. Roasting peanuts makes this protein more effective at blocking protein digestion. Thus, once a person with peanut sensitivity ingests Ara h2, other undigested proteins in the peanuts cause further allergic reactions. Boiled or raw peanuts have less effective Ara h2, so are far less likely to trigger allergic reactions than roasted peanuts.
More specifically, Ara h2 inhibits the action of the enzyme trypsin in the digestive system, which normally breaks down the peptide chains in proteins, liberating the component amino acids. These undigested peptides are thought to be a contributor to the abdominal symptoms of peanut allergies.
More about peanut allergies: http://en.wikipedia.org/wiki/Peanut#Allergies
Posted on November 3rd, 2010 No comments
First correct answer was from @rozberk: Forsythia is one of very few plants which produce lactose (milk sugar) in their nectar.
The most common sugars in nectar are more typical “plant” sugars, like sucrose and fructose, or even glucose. Forsythia produces lactose, the main sugar in the milk of mammals. Few plants produce lactose.
Forsythia is a genus of striking shrubs that produce a profusion of bright yellow flowers before the leaves in early spring. (Their common name is the same as their genus name, forsythia.) Forsythia is native to East Asia, and one species, F. europaea, is native to the Balkans. Many species, cultivars, and hybrids are commonly cultivated throughout the world, and naturalized in many places.
What are some scientific explanations – none universally accepted – for the Will-o’-the-wisp phenomenon?Posted on October 20th, 2010 No comments
First correct answer was from @little_mavis: Marsh gas is one of the weak scientific explanations for “Will-o’-the-wisp.”
Will-o’-the-wisp, also called Jack-o’Lantern or ignis fatuus (Latin for “fool’s light”), is a weird ball of light often reported in marshy areas.
While reports of Will-o’-the-wisp are frequent enough and widespread enough to elicit some scientific interest, it is too rare to study well. There have been no systematic studies of Will-o’-the-wisp, but many guesses. Since it has never really been systematically studied, we can’t call anything a scientific “explanation” of Will-o’-the-wisp.
Traditional explanations of Will-o’-the-wisp revolve around someone, variously named Will, Jack, or other names, prowling with his lantern. Jack o’ Lantern or Will o’ the Wisp, in various legends is sometimes cursed and sometimes blessed, sometimes benevolent and sometimes evil, depending on the source of the legend and perhaps the mood of the storyteller.
Among the science-based guesses about Will-o’-the-wisp:
- Marsh gas ignited by phosphines, both originating from anaerobic decay.
- Barn owls in moonlight
Some features of Will-o’-the-wisp don’t fit the marsh gas or bioluminescence explantions. For instance, it is said to move in response to the observer. Sometimes it moves toward the observer, and sometimes away. A fire in marsh gas might move at random, but it would probably not be localized, and it would not appear to be interacting with the observer. However, the barn owl explanation fits fairly well with this explanation.
Barn owls have very light-colored and reflective plumage. They fly rather slowly, as all owls do, and their wings are utterly silent as they fly. They are intelligent, curious creatures that might move toward a person at night, but they wouldn’t want to get too close.
I’m rather partial to the barn owl explanation.
More about Will-o’-the-wisp: http://en.wikipedia.org/wiki/Ignis_fatuus
Our word “mummy” comes from Persian for “bitumen.” Did ancient Egyptians use bitumen for mummification?Posted on October 18th, 2010 No comments
No correct answers to this one. No, ancient Egyptians did not use bitumen for mummification, but it was once thought so.
Bitumen was erroneously thought to account for the blackened skin of mummies. In fact, it’s a natural result of dessication.
Egyptian mummification was an elaborate process, but one of the main chemicals used was salt from salt pans and dry lakebeds in the Sahara. These salt deposits consists largely of sodium carbonate decahydrate and sodium bicarbonate, a mixture often called “natron.”
Immersing a body in bitumen might preserve it for a time, but would not likely be as effective as natron. The effect might be similar to the “natural mummification” of bog mummies immersed in peaty mud and water, but not quite. Bitumen would isolate the body from oxygen, but would not be as acidic (and so not quite as hostile to bacteria) as bog water.
More about mummies: http://en.wikipedia.org/wiki/Mummy#Etymology
Posted on September 28th, 2010 No comments
First correct answer was from @KessCat: Litmus is a mixture of dyes extracted from several kinds of lichen.
Many species of lichen produce the dyes used as litmus, which change color when exposed to acidic or basic solutions. Lichens from which litmus has been extracted include several different classes, orders, families, and genera.
Most litmus used today is extracted from lichens of genus Roccella, widely found in Africa but also in Europe and the Americas.
More about litmus: http://en.wikipedia.org/wiki/Litmus
We often hear that ice cream is thickened with extracts from seaweed. What cheaper source is replacing it?Posted on September 10th, 2010 No comments
This question was more confusing than I expected. Carageenan is a widely used thickener extracted from seaweed, but not the one I meant. (See, I hit on an inspiration for a question, but forgot the broader context. Yes, carageenan is the most frequently used thickener in ice cream, and it is still extracted exclusively from brown algae.)
Alginic acid, also called algin or alginate, is also extracted from seaweed and used as a thickener, and also for other purposes. It is algin which is also being produced by a cheaper process that does not involve seaweed. It’s produced by bacteria. Commercial quantities of algin are being produced by cultures of bacteria of genera Pseudomonas and Azotobacter.
Algin is used as a thickening agent and emulsifier in foods, especially in its salt forms, sodium alginate and potassium alginate. Algin salts are also used to produce gels for pharmaceuticals. Next time you take antibiotic gelcaps, they may be made by bacteria.
And if you don’t like the idea of seaweed in your ice cream, don’t worry about it! It might be bacteria instead.
More about bacterial algin: http://en.wikipedia.org/wiki/Alginic_acid
And some info about carageenan: http://en.wikipedia.org/wiki/Carageenan
Posted on September 8th, 2010 No comments
First correct answer was from @jchaager: Helium was first discovered on the sun, the only element first discovered in space.
The previously unknown element “helium” was proposed as an explanation for certain spectral emission lines found in the sun’s corona in 1868. Helium was discovered on earth (in natural gas deposits) in 1882, and confirmed to match the helium discovered on the sun.
The element “nebulium” was once proposed as an explanation of emissions from the Cat’s Eye Nebula, but they were later found to be emissions from doubly ionized oxygen.
More about helium: http://en.wikipedia.org/wiki/Helium
And about “nebulium”: http://en.wikipedia.org/wiki/Nebulium
Posted on August 24th, 2010 No comments
First correct answer was from @KessCat: The varnish tree is in same family (same genus, in fact) as poison ivy. The first really complete answer was from @Gday_Cate: The “active ingredient” (urushiol) is the same in varnish and in poison ivy. Uncured varnish causes “poison ivy” rash.
The varnish tree (Toxicodendron vernicifluum) produces resin nearly identical to the urushiol of poison ivy (T. radicans). Varnish tree lacquer can cause the same kind of rash that poison ivy causes (called “Toxicodendron dermatitis” or “Urushiol-induced contact dermatitis”).
Once cured, lacquer is no longer capable of producing a rash. Only the unpolymerized urushiol causes a rash.
There are many natural polymers with similar appearance (when cured) that are called “lacquer,” “shellac,” or “varnish.” Some natural “lacquers” and “shellacs” are made from various plants, insects, and other sources. Only urushiol from the Indian, Burmese, and Chinese varnish tree causes “poison ivy” rash.
Poison ivy could be used to make the same kind of lacquer as the varnish tree, but the art originated with Toxicodendron vernicifluum in India and China.
More about lacquer and poison ivy: http://en.wikipedia.org/wiki/Lacquer#Urushiol-based_lacquers
And more about the “poison ivy” rash: http://en.wikipedia.org/wiki/Urushiol-induced_contact_dermatitis
Posted on June 8th, 2010 No comments
First correct answer was from @KessCat (who’s on a roll): Poinsettia plants are mildly toxic at most.
Many plants in genus Euphorbia are toxic, and poinsettia leaves can cause some irritation, but they are not dangerous to most people. Like all members of this genus, poinsettia leaves contain latex, so people allergic to latex may be especially sensitive to poinsettia.
More about poinsettia: http://en.wikipedia.org/wiki/Euphorbia_pulcherrima
Posted on May 27th, 2010 No comments
No correct answers to this one. In astronomy, any element other than hydrogen and helium is called a “metal.”
In chemistry, a metal is any substance that readily gives up electrons in a chemical bonding reaction. “Substance” in this case may include an element, compound, or alloy. In common usage, “metal” usually refers to elements and alloys, and not to compounds.
As a consequence of the way metals form bonds, metals have their well-known characteristics of being shiny and being good conductors of electricity and heat.
But astronomers call any element with an atomic number greater than that of helium (2) a “metal.” In this sense, oxygen is a “metal.” Neon is a “metal.” Chlorine is a “metal.”
It is confusing, and not conducive to interdisciplinary cooperation when two scientific communities use the same term for different things. The argument is that the concept of a metal in the chemical sense is irrelevant in stars, as chemical bonds can not exist at high temps. So, why reuse a word that already has another meaning in another science? This just proves that scientists are not necessarily more logical than the rest of us.
More about the astronomical use of the term “metal”: http://en.wikipedia.org/wiki/Metal#Astronomy