Monthly Archives: August 2014
The chilli pepper or chilli is the fruit of plants from the genus Capsicum. The substances that give chili peppers their intensity when ingested or applied topically are capsaicin (8-methyl-N-vanillyl-6-nonenamide) and several related chemicals, collectively called capsaicinoids.
Chili peppers originated in the Americas but spread around the world and India is now the world’s largest producer, consumer and exporter of chili peppers.
When consumed, capsaicinoids bind with pain receptors in the mouth and throat that are responsible for sensing heat. Once activated by the capsaicinoids, these receptors send a message to the brain that the person has consumed something hot. The brain responds to the burning sensation by raising the heart rate, increasing perspiration and release of endorphins.
The “heat” of chili peppers was historically measured in Scoville heat units (SHU), which is a measure of the dilution of an amount of chili extract added to sugar syrup before its heat becomes undetectable to a panel of tasters; the more it has to be diluted to be undetectable, the more powerful the variety and therefore the higher the rating. The modern commonplace method for quantitative analysis of SHU rating uses high-performance liquid chromatography to directly measure the capsaicinoid content of a chili pepper variety. Pure capsaicin is a hydrophobic, colorless, odorless, and crystalline-to-waxy solid at room temperature, and measures 16,000,000 SHU.
|Chemistry of a Chilli-click to enlarge|
Capsaicin extracted from chillis is also used in pepper spray as an irritant, a form of less-lethal weapon.
Red chilies contain large amounts of vitamin C and small amounts of carotene (provitamin A). Yellow and especially green chilies (which are essentially unripe fruit) contain a considerably lower amount of both substances. In addition, peppers are a good source of most B vitamins, and vitamin B6 in particular. They are very high in potassium, magnesium, and iron. Their very high vitamin C content can also substantially increase the uptake of non-heme iron from other ingredients in a meal, such as beans and grains.
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It’s still summer – or at least it was sunny when I wrote this. Knowing the British weather it could be raining now. However rain doesn’t always stop the effects of hayfever.
Allergic rhinitis is an allergic inflammation of the nasal airways. It occurs when an allergen, such as pollen, dust or animal dander (particles of shed skin and hair) is inhaled by an individual with a sensitized immune system. In such individuals, the allergen in affected individuals is mistakenly identified as a threat and triggers the production of the antibody immunoglobulin E (IgE), which binds to mast cells and basophils containing histamine. When caused by pollens of any plants, it is called pollinosis, and, if specifically caused by grass pollens, it is known as hay fever. While symptoms resembling a cold or flu can be produced by an allergic reaction to pollen from plants and grasses it does not cause a fever.
To reduce the symptoms of hayfever science has developed a number of medications to alleviate or prevent the symptoms. A fantastic website (Compound Interest) goes into this in much more detail including the amazing infographic below.
|Click to enlarge|
Antihistamine drugs include those such as cetirizine and loratadine. They work by binding to the H1 receptors that histamine usually binds to, preventing it from inducing an inflammatory response to the allergens. As you can see from the infographic above some drugs must be taken before symptoms appear for them to be effective. Click here for a full screen image.
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|This is a simulation of the Brownian motion of a big particle (dust particle) that collides with a large set of smaller particles (molecules of a gas) which move with different velocities in different random directions.|
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BLOODHOUND SSC is a SuperSonic Car. It’s supersonic because it is designed to go faster than the speed of sound and it’s a car because it has four wheels and is under full control of its driver.
BLOODHOUND SSC is a jet and rocket powered car designed to go at 1,000 mph (just over 1,600 kph). It has a slender body of approximately 14m length with two front wheels within the body and two rear wheels mounted externally within wheel fairings. It weighs over 7 tonnes and the engines produce more than 135,000 horsepower – more than 6 times the power of all the Formula 1 cars on a starting grid put together!
The Car is a mix of car and aircraft technology, with the front half being a carbon fibre monocoque like a racing car and the back half being a metallic framework and panels like an aircraft.
Runway testing of up to 200 miles per hour (320 km/h) is scheduled to take place early 2016. Bloodhound SSC will then be tested on the Hakskeen Pan in the Mier area of the Northern Cape, South Africa where a track 12 miles (19 km) long, 2 miles (3.2 km) wide has been cleared.
The car is an amazing feat of engineering. A prototype Eurojet EJ200 jet engine developed for the Eurofighter and bound for a museum, was donated to the project. This will take the car to 300 mph (480 km/h), after which a bespoke hybrid rocket designed by Nammo will boost the car up to 1,000 miles per hour (1,609 km/h). A third engine, a 750 hp (560 kW) 2.4 Litre Cosworth CA2010 Formula 1 V8 petrol engine, is used as an auxiliary power unit and to drive the oxidiser pump for the rocket. The jet engine will provide nine tonnes of thrust and the rocket will add another 12. The supersonic car will have roughly the same power as 180 F1 cars.
The Bloodhound SSC project has a comprehensive website as below:-
They are on Twitter and regularly post updates. An example is the fascinating infographic below – 10 astounding facts about Bloodhound SSC.
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Strontium has the atomic symbol Sr and the atomic number 38. It is a soft silver-white or yellowish (when oxidised) metallic element that is even more chemically reactive than its neighbour calcium.
Strontium is a grey, silvery metal that is softer than calcium and even more reactive toward water, with which it reacts on contact to produce strontium hydroxide and hydrogen gas. Finely powdered strontium metal ignites spontaneously in air at room temperature. Most of us will be familiar with strontium because strontium salts are commonly used in fireworks and flares to give a bright (some might say blinding) red color to flames.
Strontium is named after Strontian, a village in Scotland near which the mineral was first discovered in 1790. Strontium is the 15th most abundant element on Earth, but because of its reactivity, strontium is not found roaming freely in the wild: it occurs in minerals, mostly in strontianite and celestite.
Because its nucleus is very nearly the same size as that of calcium, the body mistakenly takes up strontium and incorporates it into bones and tooth enamel in the place of calcium. Surprisingly, this is not a health problem and in fact, it can provide a health benefit. For example, in clinical trials, the drug strontium ranelate was found to aid bone growth, increase bone density, and lessen vertebral, peripheral, and hip fractures in women.
The radioactive isotope, 90Sr, is common in radioactive fallout. Since radioactive fallout doesn’t respect national borders, it falls upon all living things regardless of nationality or species, contaminating water, food and even the air that we all breathe. This isotope is quite dangerous and can cause a variety of leukæmias, bone cancer and other debilitating bone diseases. Perhaps ironically, Strontium-90 is also used to treat cancer.
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