Glutathione

Glutathione (GSH) is an important antioxidant in plants, animals, fungi, and some bacteria and archaea, preventing damage to important cellular components caused by reactive oxygen species such as free radicals, peroxides, lipid peroxides and heavy metals. It is a tripeptide with a gamma peptide linkage between the carboxyl group of the glutamate side-chain and the amine group of cysteine (which is attached by normal peptide linkage to a glycine).

Thiol groups are reducing agents, existing at a concentration around 5 mM in animal cells. Glutathione reduces disulfide bonds formed within cytoplasmic proteins to cysteines by serving as an electron donor. In the process, glutathione is converted to its oxidized form, glutathione disulfide (GSSG), also called L-(–)-glutathione.

Once oxidized, glutathione can be reduced back by glutathione reductase, using NADPH as an electron donor. The ratio of reduced glutathione to oxidized glutathione within cells is often used as a measure of cellular toxicity.

GSh-18

The GSh-18 (Cyrillic: ГШ-18) is a 9 mm semi-automatic pistol developed by the KBP Instrument Design Bureau in Tula during the 1990s. The pistol's name is derived from its designers — Gryazev and Shipunov, and the number 18 denotes the magazine capacity.

Design details

The GSh-18 is a rotating-barrel, short recoil, locked-breech pistol with 10 locking lugs spaced equally around the barrel, the large locking surface area resulting in a strong lockup, making it suitable for high-velocity ammunition loads. The GSh-18 may be employed using standard 9x19mm Parabellum rounds, but was designed for the high velocity, Russian armour-piercing 7N31 9x19mm round. The pistol incorporates a pre-set striker.. The slide and working parts are steel, and the weapon has a polymer frame. Two different designs of grip have been observed. The magazine capacity is 18 rounds, and an additional round may be carried in the chamber. Unusually for a pistol, the magazines are of the two-position feed type, meaning the rounds feed into the chamber from alternate left and right positions in the magazine similar to most rifles, instead of the single-position feed type used by the Browning Hi-Power and derivatives, where the staggered column of rounds is compressed into a single column as they rise to the top of the magazine. Disassembly is slightly more complex, with more dismountable parts, than a typical Browning derivative, such as the SIG Sauer P226, Glock 17 or CZ-75. The magazine release is reversible for left-handed shooters and the ejector doubles as a loaded chamber indicator.

Gryazev-Shipunov GSh-6-30

The Gryazev-Shipunov GSh-6-30 (Russian: Грязев-Шипунов ГШ-6-30) is a Russian 30 mm Gatling-style aircraft-mounted and naval autocannon used by Soviet and later CIS military aircraft. The GSh-6-30 fires a 30×165mm, 390 g (13¾ oz) projectile.

Description

The GSh-6-30, designed in the early 1970s and entering service in 1975, has a six barrel design that is similar to the Gryazev-Shipunov GSh-6-23. It was based on the naval AO-18 used in the AK-630 system. Unlike most modern American rotary cannons, it is gas-operated rather than hydraulically driven, allowing it to "spin up" to maximum rate of fire more quickly, allowing more rounds to be placed on target in a short-duration burst. This makes the weapon advantageous in dogfights, where pilots often have a very small window for engaging the enemy. Ignition is electrical, as with the smaller GSh-6-23.

On the Mikoyan MiG-27 the GSh-6-30 had to be mounted obliquely to absorb recoil. The gun was noted for its high (often uncomfortable) vibration and extreme noise. The airframe vibration led to fatigue cracks in fuel tanks, numerous radio and avionics failures, the necessity of using runways with floodlights for night flights (as the landing lights would often be destroyed), tearing or jamming of the forward landing gear doors (leading to at least three crash landings), cracking of the reflector gunsight, an accidental jettisoning of the cockpit canopy and at least one case of the instrument panel falling off in flight. The weapons also dealt extensive collateral damage, as the sheer numbers of fragments from detonating shells was sufficient to damage aircraft flying within a 200 meter radius from the impact center, including the aircraft firing.