Dental explorer

A dental explorer or sickle probe is an instrument in dentistry commonly used in the dental armamentarium. A sharp point at the end of the explorer is used to enhance tactile sensation.

In the past it was usual for dentists to use the explorer to determine the presence of tooth decay on tooth enamel. Some dental professionals have questioned this practice in the first decade of the twenty-first century. Since enamel is demineralized in the early stages of tooth decay, the use of an explorer opens a cavity in the enamel where none existed previously. Instead, they argue that fluoride and oral hygiene should be used to remineralize the enamel and prevent it from decaying further. This debate still continues because sometimes decay can be difficult to diagnose without tactile verification. Additionally, radiographs and other products designed to identify decay (such as measuring fluorescence from a laser) help the dental professional make a final diagnosis of tooth decay.

There are various types of explorers, though the most common one is the No. 23 explorer, which is also known as a "shepherd's hook". Other types include the 3CH (also known as "cowhorn" or "pigtail") and No. 17 explorers, which are useful for the interproximal areas between teeth.

Cosmopolis XXI

Cosmopolis XXI was a late 2000s Russian concept launch vehicle billed as a space tourism vehicle, similar to Mojave Aerospace's Tier One program. Designed and built by the Myasishchev Design Bureau, it would use the M-55X launch aircraft (derived from Myasishchev M-55), and the proposed C-21 spaceplane or its successor the Explorer. It would be a TSTSO (Two-Stage to SubOrbit) launch platform.

The Explorer spaceplane is a suborbital tourist spaceplane based on the C-21 design. The plane is being developed by Space Adventures with the Russian Federal Space Agency and is designed to carry 3 passengers. It is to be air-launched by carrier aircraft from a Space Adventures spaceport. The spaceport for the Explorer is being developed with Prodea (the company of Anousheh and Amir Ansari, who funded the Ansari X-Prize) in the United Arab Emirates, the Ras Al Khaimah spaceport.

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Explorer (sternwheeler)

Explorer was a small custom made stern-wheel steamboat built for Second lieutenant Joseph Christmas Ives and used by him to carry the U. S. Army Corps of Topographical Engineers expedition to explore the Colorado River above Fort Yuma in 1858.

History

After inquiring about the cost of chartering one of the Colorado River steamboats of George Alonzo Johnson, and finding their rates too high, Lt. Ives ordered a steamboat built in 1857:

After being transported by the Panama Railroad across the Isthmus to the Pacific Ocean the Explorer was shipped again by steamship from Panama City up to San Francisco. From there expedition sailed with the parts of the steamboat on the deck of the schooner Monterey to the Colorado River Delta where it arrived November 30. There Ives oversaw its reassembly and launch on December 30, 1857 at Robinson's Landing, Baja California. David C. Robinson, owner of the landing and a pilot for George Alonzo Johnson, was made captain of the boat.

After Ives used the Explorer to ascend the Colorado River he sent it back to Fort Yuma with Richardson. There it was put up for auction and sold to George A. Johnson for $1000. He had its engine and paddle wheel removed and used it for a barge to carry firewood to steamboat landings. In 1864 it broke free from it moorings at Pilot Knob and was carried away 60 miles down river into the Delta where it sank in a slough, sometimes seen by passing steamers, until the river moved away from the location and it was hidden by the delta foliage and lost. Its wreck was found in 1929, by a survey party, in a dried up slough miles away from the new course of the river. A mere skeleton remained, its iron plates long ago removed to make comales for baking tortillas.