Nerve agents, sometimes called nerve gases, are a class of organic chemicals that disrupt the mechanisms by which nerves transfer messages to organs. The disruption is caused by the blocking of acetylcholinesterase, an enzyme that catalyzes the breakdown of acetylcholine, a neurotransmitter. Poisoning by a nerve agent leads to constriction of pupils, profuse salivation and involuntary urination and defecation, with the first symptoms appearing in seconds after exposure. Death by asphyxiation or cardiac arrest may follow in minutes due to the loss of the body's control over respiratory and other muscles; some nerve agents are vaporized or aerosolized, the primary portal of entry into the body is the respiratory system. Nerve agents can be absorbed through the skin, requiring that those to be subjected to such agents wear a full body suit in addition to a respirator. Nerve agents are colorless to amber-colored, tasteless liquids that may evaporate to a gas. Agents sarin and VX are odorless. Nerve agents attack the nervous system.
All such agents function the same way resulting in cholinergic crisis: they inhibit the enzyme acetylcholinesterase, responsible for the breakdown of acetylcholine in the synapses between nerves that control muscle contraction. If the agent cannot be broken down, muscles are prevented from relaxing and they are paralyzed; this includes the muscles used for breathing. Because of this, the first symptoms appear within seconds of exposure and death can occur via asphyxiation or cardiac arrest in a few minutes. Initial symptoms following exposure to nerve agents are a runny nose, tightness in the chest, constriction of the pupils. Soon after, the victim will experience nausea and salivation; as the victim continues to lose control of bodily functions, involuntary salivation, urination, gastrointestinal pain and vomiting will be experienced. Blisters and burning of the eyes and/or lungs may occur; this phase is followed by myoclonic jerks followed by status epilepticus -type epileptic seizure. Death comes via complete respiratory depression, most via the excessive peripheral activity at the neuromuscular junction of the diaphragm.
The effects of nerve agents increase with continued exposure. Survivors of nerve agent poisoning invariably suffer chronic neurological damage and related psychiatric effects. Possible effects that can last at least up to 2–3 years after exposure include blurred vision, declined memory, hoarse voice, sleeplessness, shoulder stiffness and eye strain. In people exposed to nerve agents and erythrocyte acetylcholinesterase in the long-term are noticeably lower than normal and tend to be lower the worse the persisting symptoms are; when a functioning motor nerve is stimulated, it releases the neurotransmitter acetylcholine, which transmits the impulse to a muscle or organ. Once the impulse is sent, the enzyme acetylcholinesterase breaks down the acetylcholine in order to allow the muscle or organ to relax. Nerve agents disrupt the nervous system by inhibiting the function of the enzyme acetylcholinesterase by forming a covalent bond with its active site, where acetylcholine would be broken down. Acetylcholine thus builds up and continues to act so that any nerve impulses are continually transmitted and muscle contractions do not stop.
This same action occurs at the gland and organ levels, resulting in uncontrolled drooling, tearing of the eyes and excess production of mucus from the nose. The reaction product of the most important nerve agents, including soman, tabun and VX, with acetylcholinesterase were solved by the U. S. Army using X-ray crystallography in the 1990s; the reaction products have been confirmed subsequently using different sources of acetylcholinesterase and the related target enzyme, butyrylcholinesterase. The X-ray structures clarify important aspects of the reaction mechanism at atomic resolution and provide a key tool for antidote development. Atropine and related anticholinergic drugs act as antidotes to nerve agent poisoning because they block acetylcholine receptors, but they are poisonous in their own right; some synthetic anticholinergics, such as biperiden, may counteract the central symptoms of nerve agent poisoning better than atropine, since they pass the blood–brain barrier better than atropine.
While these drugs will save the life of a person affected by nerve agents, that person may be incapacitated or for an extended period, depending on the extent of exposure. The endpoint of atropine administration is the clearing of bronchial secretions. Atropine for field use by military personnel is loaded in an autoinjector, for ease of use in stressful conditions. Pralidoxime chloride known as 2-PAM chloride, is used as an antidote. Rather than counteracting the initial effects of the nerve agent on the nervous system as does atropine, pralidoxime chloride reactivates the poisoned enzyme by scavenging the phosphoryl group attached on the functional hydroxyl group of the enzyme. Though safer to use than atropine, it takes longer to act. Revival of acetylcholinesterase with pralidoxime chloride works more on nicotinic receptors while blocking acetylcholine receptors with atropine is more effective on muscarinic receptors. Severe cases of poisoning are treated with both drugs. Butyrylcholinesterase is under development by the U.
The 1992 Full Members' Cup final known by its sponsored name, the Zenith Data Systems Cup, was a football match which took place at Wembley Stadium on 29 March 1992. It was contested between Nottingham Southampton; the match was shown live on Sky Sports. Scot Gemmill opened the scoring for Nottingham Forest in the 15th minute with a right foot volley from the right of the penalty area. Kingsley Black got the second with a low left footed shot into the corner of the net. Southampton got one back in the 64th minute with Matt Le Tissier header from six yards out after a cross from the left. Southampton equalised six minutes when Kevin Moore headed in from six yards after a corner from the right; the match went to extra time and Scot Gemmill got the winning goal and his second with five minutes remaining when he volleyed in from six yards after a cross from the right. Des Walker collected the trophy, having taken over as captain when Stuart Pearce was substituted with an injury in the first half. Note: Flags indicate national team as defined under FIFA eligibility rules.
Players may hold more than one non-FIFA nationality
A polity is an identifiable political entity—any group of people who have a collective identity, who are organized by some form of institutionalized social relations, have a capacity to mobilize resources. A polity can be any other group of people organized for governance, the government of a country, or country subdivision. In geopolitics, a polity can be manifested in different forms such as a state, an empire, an international organization, a political organization and other identifiable, resource-manipulating organizational structures. A polity like a state does not need to be a sovereign unit; the most preeminent polities today are Westphalian states and nation-states referred to as nations. A polity encapsulates a vast multitude of organizations, many of which form the fundamental apparatus of contemporary states such as their subordinate civil and local government authorities. Polities do not need to be in control of any geographic areas, as not all political entities and governments have controlled the resources of one fixed geographic area.
The historical Steppe Empires originating from the Eurasian Steppe are the most prominent example of non-sedentary polities. These polities differ from states because of their lack of a defined territory. Empires differ from states in that their territories are not statically defined or permanently fixed and that their body politic was dynamic and fluid, it is useful to think of a polity as a political community. A polity can be defined either as a faction within a larger entity or at different times as the entity itself. For example, Kurds in Iraqi Kurdistan are parts of their own distinct polity. However, they are members of the sovereign state of Iraq, itself a polity, albeit one, much less specific and as a result much less cohesive. Therefore, it is possible for an individual to belong to more than one polity at a time. Thomas Hobbes was a significant figure in the conceptualisation of polities, in particular of states. Hobbes considered notions of the state and the body politic in his most notable work.
In previous centuries, a body politic was understood to mean "the physical person of the sovereign", i.e. emperor, monarch or dictator in monarchies and despotisms and the electorate in republics. As many polities have become more democratic in the last few centuries the body politic, where sovereignty is bestowed, has grown to a much greater size than the ruling elite such as the monarchy. In present times, it may refer to the representation of a group such as ones drawn along ethnic or gender lines. Cabinets in liberal democracies are chosen to represent the body politic. Kokutai Politeia Political system Dictionary of the History of Ideas – analogy of the body politic