Tropomyosin 3

Tropomyosin alpha-3 chain is a protein that in humans is encoded by the TPM3 gene.

This gene encodes a member of the tropomyosin family of actin-binding proteins involved in the contractile system of striated and smooth muscles and the cytoskeleton of non-muscle cells. Tropomyosins are dimers of coiled-coil proteins that polymerize end-to-end along the major groove in most actin filaments. They provide stability to the filaments and regulate access of other actin-binding proteins. In muscle cells, they regulate muscle contraction by controlling the binding of myosin heads to the actin filament. Mutations in this gene result in autosomal dominant nemaline myopathy, and oncogenes formed by chromosomal translocations involving this locus are associated with cancer. Multiple transcript variants encoding different isoforms have been found for this gene.

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TPM2

β-Tropomyosin, also known as tropomyosin beta chain is a protein that in humans is encoded by the TPM2 gene. β-tropomyosin is striated muscle-specific coiled coil dimer that functions to stabilize actin filaments and regulate muscle contraction.

Structure

β-tropomyosin is roughly 32 kDa in molecular weight (284 amino acids), but multiple splice variants exist. Tropomysin is a flexible protein homodimer or heterodimer composed of two alpha-helical chains, which adopt a bent coiled coil conformation to wrap around the seven actin molecules in a functional unit of muscle. It is polymerized end to end along the two grooves of actin filaments and provides stability to the filaments. Tropomyosin dimers are composed of varying combinations of tropomyosin isoforms; human striated muscles express protein from the TPM1 (α-tropoomyosin), TPM2 (β-tropomyosin) and TPM3 (γ-tropomyosin) genes, with α-tropomyosin being the predominant isoform in striated muscle. Fast skeletal muscle and cardiac muscle contain more αα-homodimers, and slow skeletal muscle contains more ββ-homodimers. In human cardiac muscle the ratio of α-tropomyosin to β-tropomyosin is roughly 5:1. It has been shown that different combinations of tropomyosin isoforms bind troponin T with differing affinities, demonstrating that isoform combinations are used to impart a specific functional impact.

Bike

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Generic top-level domain

Generic top-level domains (gTLDs) are one of the categories of top-level domains (TLDs) maintained by the Internet Assigned Numbers Authority (IANA) for use in the Domain Name System of the Internet. A top-level domain is the last label of every fully qualified domain name. They are called generic for historic reasons; initially, they were contrasted with country-specific TLDs in RFC 920.

The core group of generic top-level domains consists of the com, info, net, and org domains. In addition, the domains biz, name, and pro are also considered generic; however, these are designated as restricted, because registrations within them require proof of eligibility within the guidelines set for each.

Historically, the group of generic top-level domains included domains, created in the early development of the domain name system, that are now sponsored by designated agencies or organizations and are restricted to specific types of registrants. Thus, domains edu, gov, int, and mil are now considered sponsored top-level domains, much like the themed top-level domains (e.g., jobs). The entire group of domains that do not have a geographic or country designation (see country-code top-level domain) is still often referred to by the term generic TLDs.

Recumbent bicycle

A recumbent bicycle is a bicycle that places the rider in a laid-back reclining position. Most recumbent riders choose this type of design for ergonomic reasons; the rider's weight is distributed comfortably over a larger area, supported by back and buttocks. On a traditional upright bicycle, the body weight rests entirely on a small portion of the sitting bones, the feet, and the hands.

Most recumbent models also have an aerodynamic advantage; the reclined, legs-forward position of the rider’s body presents a smaller frontal profile. A recumbent holds the world speed record for a bicycle, and they were banned from racing under the Union Cycliste Internationale (UCI) in 1934, and now race under the banner of the Human Powered Vehicle Association (HPVA).

Recumbents are available in a wide range of configurations, including: long to short wheelbase; large, small, or a mix of wheel sizes; overseat, underseat, or no-hands steering; and rear wheel or front wheel drive. A variant with three wheels is a recumbent tricycle.

War

War is a state of armed conflict between societies. It is generally characterized by extreme collective aggression, destruction, and usually high mortality. The set of techniques and actions used to conduct war is known as warfare. An absence of war is usually called "peace". Total war is warfare that is not restricted to purely legitimate military targets, and can result in massive civilian or other non-combatant casualties.

While some scholars see war as a universal and ancestral aspect of human nature, others argue that it is only a result of specific socio-cultural or ecological circumstances.

In 2013 war resulted in 31,000 deaths down from 72,000 deaths in 1990. The deadliest war in history, in terms of the cumulative number of deaths since its start, is the Second World War, from 1939 to 1945, with 60–85 million deaths, followed by the Mongol conquests which was greater than 41 million. Proportionally speaking, the most destructive war in modern history is the War of the Triple Alliance, which took the lives of over 60% of Paraguay's population, according to Steven Pinker. In 2003, Richard Smalley identified war as the sixth (of ten) biggest problem facing humanity for the next fifty years. War usually results in significant deterioration of infrastructure and the ecosystem, a decrease in social spending, famine, large-scale emigration from the war zone, and often the mistreatment of prisoners of war or civilians. Another byproduct of some wars is the prevalence of propaganda by some or all parties in the conflict, and increased revenues by weapons manufacturers.