Triad (anatomy)

In the histology of skeletal muscle, a triad is the structure formed by a T tubule with a sarcoplasmic reticulum (SR) known as the terminal cisterna on either side. Each skeletal muscle fiber has many thousands of triads, visible in muscle fibers that have been sectioned longitudinally. (This property holds because T tubules run perpendicular to the longitudinal axis of the muscle fiber.) In mammals, triads are typically located at the A-I junction; that is, the junction between the A and I bands of the sarcomere, which is the smallest unit of a muscle fiber.

Triads form the anatomical basis of excitation-contraction coupling, whereby a stimulus excites the muscle and causes it to contract. A stimulus, in the form of positively charged current, is transmitted from the neuromuscular junction down the length of the T tubules, activating dihydropyridine receptors (DHPRs). Their activation causes 1) a negligible influx of calcium and 2) a mechanical interaction with calcium-conducting ryanodine receptors (RyRs) on the adjacent SR membrane. Activation of RyRs causes the release of calcium from the SR, which subsequently initiates a cascade of events leading to muscle contraction. These muscle contractions are caused by calcium's bonding to troponin and unmasking the binding sites covered by the troponin-tropomyosin complex on the actin myofilament and allowing the myosin cross-bridges to connect with the actin.

Luornu Durgo

Triplicate Girl (Luornu Durgo) is a fictional character, a superhero in the 30th and 31st centuries of the DC Comics Universe and a member of the Legion of Super-Heroes. She has also had the aliases Duo Damsel, Triad, Una, Duplicate Damsel and Duplicate Girl and was ranked 33rd in Comics Buyer's Guide's 100 Sexiest Women in Comics list.

Fictional character biography

Original continuity

Luornu Durgo, codenamed Triplicate Girl, first appeared in Action Comics #276, written by Jerry Siegel. A native of the planet Cargg, she could split into three identical bodies, as could all Carggites, due to the planet Cargg having three suns. Her costume consisted of a purple dress, orange cape and belt, and black boots.

She was the fourth hero to join the Legion of Super-Heroes, and its first non-founder member. Unlike her post-Zero Hour counterpart, Triad, she had brown eyes, not split purple/orange ones. For a long time, she had an unrequited crush on Superboy.

One of her three bodies was killed by Brainiac 5's killer creation Computo The Conqueror (a rogue computer) early on, and she was thereafter known as Duo Damsel. Her surviving two bodies continued to remember the trauma of experiencing her/their death, with the result that Computo was the one villain whom Duo Damsel was too frightened to confront.

Triad (sculpture)

Triad is an outdoor sculpture by German American artist Evelyn Franz, located in Laurelhurst Park in southeast Portland, Oregon.

Description and history

Originally completed in 1980 and remade in 2003, Triad was designed by Evelyn Franz, who received her Master of Fine Arts in Sculpture in 1976 from Portland State University. The abstract stainless steel sculpture was funded by CETA and is installed between Southeast 37th Avenue and Southeast Ankeny in Laurelhurst Park. According to the Regional Arts & Culture Council, which administers the work, it measures 7 feet (2.1 m), 5 inches (13 cm) x 5 feet (1.5 m), 5 inches (13 cm) x 2 feet (0.61 m), 5 inches (13 cm). The Smithsonian Institution lists the measurements as approximately 50 inches (130 cm) x 8 feet (2.4 m) x 2 feet (0.61 m). The sculpture contains no inscriptions and rests on a stainless steel base which measures approximately 16 inches (41 cm) x 80 inches (200 cm) x 30 inches (76 cm). It is part of the City of Portland and Multnomah County Public Art Collection courtesy of the Regional Arts & Culture Council.

Heiden

Heiden may refer to:

Municipalities

People

Other uses

See also

Heiden, Switzerland

Heiden is a municipality in the canton of Appenzell Ausserrhoden in Switzerland. Its Biedermeier village around the church square is listed as a heritage site of national significance.

History

Heiden is first mentioned in 1461 as guot genant Haiden.

Around 1650 Wolfhalden and Heiden could not agree about the control over the church. This led to the creation of a church in each village in 1652, making them independent.

The founder of the Red Cross, Henry Dunant, spent his last years in Heiden. The former president of the ICRC, Jakob Kellenberger, was also born in Heiden.

Geography

Heiden has an area, as of 2006, of 7.5 km² (2.9 sq mi). Of this area, 52.4% is used for agricultural purposes, while 30.6% is forested. Of the rest of the land, 16.8% is settled (buildings or roads) and the remainder (0.3%) is non-productive (rivers, glaciers or mountains).

The municipality is located in the former District of Vorderland on the Kurzenberg. It consists of the village of Heiden and several hamlets near the village.