Interesting Excerpts -- Nanotech, Black Color

Nanotechnology: A little risky business (The Economist, Nov 22nd 2007)

In the past few years the number of consumer products claiming to use nanotechnology has dramatically grown—to almost 600 by one count....Some nanotechnology products are applied directly to the skin, as cosmetics and sunscreens. Titanium dioxide is commonly used as the white pigment in sunscreen. When it is ground into nanoparticles it can still block harmful ultraviolet radiation, but it allows visible light to pass straight though, which means modern sunscreens can appear completely transparent, while offering the same protection as the old white stuff.

Many products are now embedded with silver nanoparticles. At such small sizes, silver can have antimicrobial properties. Silver nanoparticles may come in handy wherever you want to kill germs—for instance, in things as diverse as children's dummies (comforters to Americans), teddy bears, washing machines, chopsticks and bed linen. Hence nanotechnology can be used in food production, most often as nanoparticles of silver in food-preparation equipment. The food industry is also trying to restructure ingredients at the nanoscale so as to include particles of trace metals in food supplements and to produce less-fattening foods.

Research on animals suggests that nanoparticles can even evade some of the body's natural defence systems and accumulate in the brain, cells, blood and nerves...Half of the atoms in a five-nanometre particle are on its surface, which can make it many times more toxic than expected by weight alone.

Carbon nanotubes have been used for years in industry. They have been embedded in materials like plastics to increase their toughness and provide electrical conductivity for components that are electrostatically painted. But it remains unknown, for instance, if they can enter groundwater when the products that contain them are dumped or broken up.

Painting it Black (Japan Journal, Oct., 2007)

For long, the color was a secret symbol of virility and power. Along with gold, it was the most favored color among warlords, the prime example being Oda Nobunaga (the first warlord to unify the nation), who refused to dine off anything but the blackest of lacquered tableware. In the fourteenth and fifteenth centuries women blackened their teeth, initially to emphasize their sexuality. Later, during the Edo period (1603–1867), wives dyed their teeth black as a sign of unavailability (a Japanese version of the wedding ring), though in many cases this served as the ultimate turn-on—much of Edo pornography (both art and literature) features black-teethed wives in the throes of ecstasy. Women drew the line when it came to dress however; black was too ceremonial, heavy, and laden with male aesthetics/subtexts.

The black boom of today has its roots in the revival of Japanese charcoal (sumi - 炭). Once the most ubiquitous of household supplies, Japanese charcoal (used not just for fuel but also for medication and as a purifier) had given way to mass-produced, high-tech products...