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"Salvinia Effect" of Salvinia natans

Scanning electron micrograph of leaf detail of Salvinia natans, a floating fern type plant which has superhydrophobic trichomes or hairs on the upper surface of its leaves. Each of these eggbeater shaped hairs exhibits a hydrophilic tip on the top of each hydrophobic hair. The combination of a hydrophobic surface with hydrophilic tips is called the "Salvinia Effect". These air retaining surfaces are of great interest, particularly with regards to fuel consumption when applied to ships having to overcome friction produced by the drag of water on their hulls. This drag could be reduced dramatically with the "Salvinia Effect", a layer of air between the ship's hull and the water, saving vast amounts of fuel. A suggested estimated saving of 20 million tons of oil per year for just a 10% decrease in drag for shipping alone. Magnification: x372 (x122 at 10cm wide)

© POWER AND SYRED/SCIENCE PHOTO LIBRARY

Cave of Crystals, Naica Mine, Mexico

^BCave of Crystals.^b Geologist standing in the Cave of Crystals (^ICueva de los Cristales^i) in Naica Mine, Chihuahua, Mexico. The crystals are the largest known in the world, and are formed of the selenite form of gypsum (calcium sulphate). They formed over millions of years in the mineral-rich geothermally heated water that filled the caves. The crystals were discovered after the water was pumped out of the mine. The Cave of Crystals is 290 metres deep, and was discovered in 2000. Above it, 120 metres deep, is the Cave of Swords (^ICueva^i ^Ide^i ^Ilas Espadas^i), which was discovered in 1912. The crystals in this cave are smaller as its water cooled more rapidly.

© JAVIER TRUEBA/MSF/SCIENCE PHOTO LIBRARY

Dolly, the world's first adult sheep clone

^B"Dolly", the sheep clone.^b Eight month old "Dolly", the world's first sheep cloned from an adult sheep cell. She is the result of research conducted by Dr. Ian Wilmut at the Roslin Institute in Edin- burgh, Scotland. Wilmut's work involved taking an egg cell from a Scottish Blackface (SB) ewe and removing the cell nucleus. Next, an adult cell from the udder of a 6-year-old Finn Dorset ewe was cultured and then injected into the enucleated egg cell. A spark of electricity then fused the udder cell with the egg cytoplasm and stimulated the egg to grow into an embryo in the womb of a surrogate SB sheep. In 1997, Wilmut introduced to the world "Dolly", the first such sheep clone.

© PHILIPPE PLAILLY/SCIENCE PHOTO LIBRARY