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Glossary of rugby union terms
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K
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Kick-off A coin is tossed and the winning captain either chooses which direction his team shall play, or elects to take the kick that starts the game. Both halves of the match are started with a drop kick from the centre-point of the halfway line. The kick must cross the opposition's 10-metre line, unless played by a member of the receiving team. The opposition are not allowed to encroach beyond the 10-metre line until the ball is kicked.If the ball does not travel 10 metres, goes straight into touch, or goes over the dead ball line at the end of the pitch, the opposing team may accept the kick, have the ball kicked off again, or have a scrum at the centre.After a score, the game is restarted from the same place under the same restrictions, with the conceding team drop-kicking the ball to the scoring team. However, in sevens, the scoring team kicks off.Kick tennis Style of play characterised by both teams repeatedly kicking from hand to the opposition, rather than running at the opposition and risking a turnover. So-called because the ball moves back and forth like in a tennis match. It is considered boring to watch and also referred to as aerial ping-pong.Knock-on Also called knock-forward. A knock-on occurs when the ball accidentally moves forward after coming into contact with the upper body of a player, and then touches either the ground or another player. It results in a scrum with the put-in to the opposition. If the ball is intentionally knocked forward it is deemed a deliberate knock-on; the opposition is rewarded with a penalty and the offending player is given a yellow card and sent to the sin bin.
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Glossary of rugby union terms
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L
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Latcher/Latching on A latcher is a player who binds himself to the ballcarrier in open play in order to add his power and weight to an attempt to break the line and gain yards. If the defence is able to stop the ballcarrier and hold him up, a maul usually forms. However latching on does not automatically create a maul.Late tackle A late tackle is a tackle executed on a player who has already passed or kicked away the ball. As it is illegal to tackle a player who does not have the ball, late tackles are penalty offences (referees allow a short margin of error where the tackler was already committed to the tackle) and if severe or reckless may result in yellow or red Cards.If a late tackle occurs after a kick and a penalty is awarded, the non-offending team has the option of taking the penalty where the ball landed.
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Glossary of rugby union terms
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L
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Line break Action by which the player with the ball gets through the opponent's defensive line without being tackled. If there is insufficient cover, or the player has support, line breaks can often lead to tries.Line-out A minimum of two players line up parallel with each other one metre apart between the five-metre and 15-metre lines. Usually, the hooker of the team in possession throws the ball in while his opposite number [may] stand in between the touchline and the five-metre line.All players not involved in the lineout, except the receiver (usually the scrum-half) must retire 10 metres.The ball must be thrown in straight down the middle of the lineout and the hooker must not cross into the field of play while throwing in. If the throw is not straight then the throw is given to the opposition or a scrum awarded.Jumpers can be lifted by their teammates below the waist, but the opposition's jumpers must not be obstructed, barged or pulled down.Line-out code It is a coded piece of information, used to communicate intentions about a line-out within one team in a match without giving information away to the other team. The advantage in line-out comes from knowing in advance how the throw will be made.Line speed The speed with which a blitz defence closes down the opposing team. A high line speed will make it difficult for the opposition to cross the gain line.Lock Locks or second-row are the players wearing shirts number 4 & 5. Locks are very tall, athletic and have an excellent standing jump along with good strength. This makes them the primary targets at line-outs. They also make good ball carriers, bashing holes in the defence around the ruck and maul. They also have to push in the rucks and mauls.
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Glossary of rugby union terms
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L
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Loose head The loose head prop is the player who takes the left hand position on the front row of the scrum. A loose head prop traditionally wears the number 1 shirt.As the loose head has considerable potential freedom of movement compared to other front row players, the loose head can attempt to play various illegal techniques to divert the push of the opposing pack and is often able to illegally interfere with the ball in the scrum using his free arm.
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Glossary of rugby union terms
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M
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Mark A mark is the place where the game will restart after a stoppage, such as where a scrum-offence or penalty offence occurred, or on the touchline where the ball went out of play (or where the ball was kicked in the case of ball-back). Marks are generally defined by the referee, or the touch judge when the ball leaves play by the touchline.Marks can also be defined by a defending player who executes a clean catch (catches the ball before it bounces or touches another player) of a ball kicked by an attacking player if the defender is standing within his/her own 22-metre zone or in-goal. To "call a mark", the player shouts "Mark!" as he/she catches the ball. The referee then awards that player a free kick which must be taken by that specific player. (If, for whatever reason, that player cannot take the kick, a scrum is awarded instead.) If the player is simply a poor kicker he/she is likely to take a 'Tap Kick' and immediately pass the ball to the fly-half or full back who will generally deliver a clearance kick.Marks can be called when the ball is cleanly caught following a kick by the opposition for any type of kick except a kick off or restart after a score. It is legal, though very unusual, to call a mark from a clean catch of a penalty kick.Maul When a ball carrier is held up (without being tackled) by both an opposing player and a player from his own team, a maul is then considered formed.The offside line becomes the last foot of the last man on each side of the maul. Players can join in only from behind that teammate. Anyone who comes in from the sides will be penalised by the referee. Hands are allowed to be used in the maul. If either team deliberately collapses the maul then that side will be penalised by the referee. (Note that from August 1, 2008, the IRB is conducting a global trial of a modification of this Law which will allow players to deliberately collapse a maul providing the collapse is achieved by pulling from above the waist.)If the ball does not come out in a timely fashion, the referee will award a scrum to the team that did not take the ball into the maul.Mauls can only exist in the field of play. Play that looks like a maul can exist within the in-goal but restrictions on entry to the maul and the need to bind on to a team member do not apply.Medical joker A player signed by a professional club as an injury replacement. The term is directly borrowed from the French joker médical and is most commonly associated with France's top league; that country has long allowed such signings.Mismatch Situation where a back is one-on-one with a forward. This favours the attacking side, as often forwards are too slow to stop backs, and backs are too small to stop forwards.Mulligrubber The mulligrubber kick is a style of kicking. A mulligrubber is directed towards the ground and forced to bounce. Often used in situations where either the ball needs to be placed in a specific position (i.e. on the try line) or to intentionally stop the opponent from being able to catch the ball on the full.
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Glossary of rugby union terms
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N
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North (to go north, to head north, etc.)In the days prior to professionalism in rugby union, players would often convert to rugby league — which was a paid sport — thereby becoming ineligible to play rugby union again. In Wales and (to a lesser extent) England, the term "to go north" referred to this change of code, an allusion to the popularity of rugby league in the north of England.Not straight Referee's call when a line-out throw or the feeding of the ball into the scrum is unfairly towards the team in possession, preventing any contest for the ball. It is punished by resetting the set piece and giving control of the ball to the opposition.Number 8 They are the players wearing shirts number 8. It is the only position that is known only by the shirt number. Number eights must have a good tactical awareness in order to coordinate scrums and ruck moves with the scrum-half. If the ball is at his feet at the back of a scrum, ruck or maul, it is normally the number eight's decision whether to pass the ball out or drive the breakdown on in order to make ground.
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Glossary of rugby union terms
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O
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Obstruction Offence whereby a player deliberately impedes an opponent who does not have the ball.Off-load pass (offload) A short pass made by a player being tackled before he reaches the ground, usually by turning to face a teammate and tossing the ball into the air for a teammate to catch.Offside A player is offside when he/she is forward of the relevant offside line i.e. between the relevant offside line and the opposing team's dead ball line.In a match, most players will be offside several times but they only become liable for penalty if they do not act to attempt to become onside (which generally means retreat downfield) or attempt to interfere with play.In open play, only the ball carrier's team (or the team that last carried or deliberately touched the ball) is bound by offside - the offside line for them is the ball. (Note every player who passes the ball backwards is offside and must attempt to retire.)An accidental offside may occur (and be penalised) if the ball carrier accidentally collides with one of his own team's players while that player is attempting to retire behind the ball (or is otherwise in an offside position).Onside A player is onside whenever he or she is behind the relevant offside line for the particular phase of play. Players who are onside take an active part in playing the game.Previously offside players may be "put onside" by the actions of other players (for example, in a kick ahead in open play, players in the kicker's team in front of the kick are offside but can be put onside by the kicker or any other team member who was onside at the time of the kick running up the pitch past them). So that players can be confident they are now onside and can take an active part in the game, the referee may shout "Onside" or "All Onside".On the full If the ball is kicked into touch without first bouncing inside the field of play it is termed as ball is kicked into touch on the full. The line-out is then taken from where the ball was kicked, except in situations where it was kicked from inside the 22.Openside The broad side of the pitch in relation to a scrum or a breakdown in play. The openside flanker is expected to cover the opposing team openside at scrum and breakdown. It is the opposite of blindside.Overlap Situation where there are more attacking players (typically backs) on one side of the field than there are defending players. An overlap can be used to manufacture a try by forcing the defenders into tackles and offloading to teammates until the defenders have run out.
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Glossary of rugby union terms
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P
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Pack The pack is another name used for the forwards players, particularly when they are bound for a scrum.Passing A pass is to transfer a ball to a teammate by throwing it. Passes in rugby must not travel forwards. There are different varieties of pass, including the flat, direct spin pass; the short, close-quarters pop pass; and the floated pass - a long pass which an advancing player can run onto at pace.Penalty Penalties are awarded for serious infringements like dangerous play, offside and handling the ball on the ground in a ruck. Penalties are signalled by the referee with a straight arm raised in the air. Players can also receive red and yellow cards, as in Association football.The offending team must retire 10 metres (or to their goal line if closer) for both penalties and free kicks. A team can either kick for goal, tap and run the ball, take a scrum or kick directly into touch with the resulting line-out awarded to them.Penalty kick If a side commits a penalty infringement the opposition can take the option of a place kick at goal from where the infringement occurred (or, if the offence occurred when a player was in the process of kicking the ball, the non-offending team can opt to take the kick from where the ball landed which may be more advantageous). This is called a penalty kick. If successful, it is worth three points.Penalty try A penalty try awarded if the referee believes a team illegally prevented a try from probably being scored. As of 2018, penalty tries score an immediate seven points, with no conversion having to be taken. Generally a penalty try is awarded when the try-preventing offence cannot be easily attributed to a single individual, such as when a team repeatedly deliberately collapses a scrum near its own tryline. When the prevention of the try is due to an individual, a yellow card is a more common punishment.Phase A phase is the time a ball is in play between breakdowns. For example, first phase would be winning the ball at the lineout and passing to a centre who is tackled. Second phase would be winning the ball back from the ensuing breakdown and attacking again.Pitch The official name of a rugby playing field. Dimensions are 100 m long by 70 m wide.Place kick The place kick is a kicking style commonly used when kicking for goal. It typically involves placing the ball on the ground. To keep the ball in position, a mound of sand or plastic tee is sometimes used.Pop pass A very short pass.Professional foul A professional foul is a deliberate act of foul play, usually to prevent an opponent scoring. It is punishable by a yellow card.Prop They are the players wearing shirts number 1 & 3. The role of both the props is to support the hooker in the scrum and to provide support for the jumpers in the line-out. The props provide the main power in the push forward in the scrum. For this reason they need to be exceptionally big and strong.
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Glossary of rugby union terms
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R
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Red card In International matches, red cards are shown by the referee to players who have been ordered off the pitch, which results in the player being removed from the game without being replaced. This usually occurs when a player is guilty of serious foul play, or violent conduct or for committing two offences resulting in cautions (yellow cards).Red cards are also commonly used in non-international matches in precisely the same manner as in International matches but there is no regulation requiring their use. (i.e. in a domestic match, a referee may dismiss a player without actually displaying a red card.)Red zone This is a term most commonly used by coaches to describe the area of the pitch between the try line and around 22 metres out, in which it is most likely a try may be scored or conceded.Restart The kick taken from the centre line after the opposition have scored points.Round the corner kicking A style of place-kicking in which the kicker, instead of facing directly toward the goal-posts, approaches the ball from an angle and swings his kicking leg in an arc. It was first credited to Wilf Wooler in the 1930s.Ruck A ruck is formed when the ball is on the ground and two opposing players meet over the ball. The offside line becomes the last foot of the last man on each side of the ruck and players compete for the ball by attempting to drive one another from the area and to 'ruck' the ball backwards with their feet.Rucks commonly form soon after tackles, but can form anywhere in the field of play where the ball is on the ground.Handling the ball while it is in the vicinity of a ruck is a penalty offence. (Though modern practice allows a player on the ground to support the ball with his/her hands and for the player who is acting as scrum half to 'dig' for the ball once possession has been secured.)If the ball remains contested and does not come out of a ruck after about five seconds, the referee will award a scrum to the team he considers to have been moving forward in the ruck.
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Glossary of rugby union terms
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S
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Scrum The eight forwards from each team bind together and push against each other. The scrum-half from the team that has been awarded possession feeds the ball into the centre of the scrum from the side most advantageous for his hooker (which is typically the side of loose head prop).The ball must be fed straight down the middle of the tunnel and the hookers must not contest for the ball until it is put in. If they do, a free-kick is awarded for "foot up".The scrum is taken again if the ball comes straight out of the tunnel or if it collapses. If the scrum wheels (rotates) due to pushing more than 90 degrees the scrum is reformed and awarded to the other side. Pulling in an attempt to unbalance the other side or to assist in rotating the scrum is a Penalty Offence.Scrum half Also known as a half-back (especially in New Zealand), they are the players traditionally wearing shirt number 9. Scrum halves form the all-important link between the forwards and the backs. They are relatively small but with a high degree of vision, the ability to react to situations very quickly, and good handling skills.They are often the first tackler in defence and are behind every scrum, maul or ruck to get the ball out and maintain movement. They put the ball into the scrum and collect it afterwards. Scrum halves generally also act as "receiver" in the line-out to catch the ball knocked down by the forwards. (The receiver is a member of the line-out and so stands within 10 metres of it and may join the line once the ball is thrown.)Selector A person who is delegated with the task of choosing players for a team. Typically the term is used in the context of team selection for a national, county, state or provincial representative side, where the selector, or "selection panel", act under the authority of the relevant national or provincial administrative body.Set piece Collective term for the scrum, line-out and sometimes the restart.Shoeing At the breakdown a ruck commonly forms over the players involved in the tackle.Where players who are on the ground on the opposition side of the ruck do not move away quickly enough, players on their feet may be tempted to "help" them move by pushing them away with their boots.This potentially dangerous act is illegal and if done deliberately (or recklessly) may result in penalties and yellow or red cards.Short arm penalty See free kickSin bin The notional area where a player must remain for a minimum of ten minutes after being shown a yellow card. In high level games, the sin bin is monitored by the fourth official.Sipi Tau Sipi Tau is a Tongan war dance performed by the Tonga national team before each of their international matches.Siva Tau Siva Tau is a Samoan war dance performed by the Samoa national team before each of their international matches.Spear tackle A spear tackle is a dangerous tackle in which a player is picked up by the tackler and turned so that they are upside down. The tackler then drops or drives the player into the ground often head, neck or shoulder first.Spear tackles are particularly dangerous and have caused serious injury, including spinal damage, dislocations and broken bones in the shoulder or neck. On rare occasion, even death can occur.Spear tackles are taken very seriously by the various Union disciplinary committees and can result in lengthy playing bans.Stellenbosch Laws The Stellenbosch Laws were a set of experimental laws of rugby union considered by World Rugby, then known as the International Rugby Board (IRB), from 2006 to 2008. The trials ended in late 2008, with the IRB choosing to adopt roughly half of the proposed changes.
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Glossary of rugby union terms
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T
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Tackle A tackle takes place when one or more opposition players [tackler(s)] grasp onto the ball carrier and succeed in bringing/pulling him/her to ground and holding them there.Once briefly held, the tackler(s) must release the tackled player who must then him/herself immediately release or attempt to pass the ball so that play can continue.Tap kick A tap kick is a type of kick used by players at penalties or free kicks to meet the regulation that requires the ball must be kicked a visible distance before a player may pass or run with it.In a tap kick, the player momentarily releases the ball from his hands and taps it with his foot or lower leg and then quickly catches it again. The player will then generally try to run forward with the ball.Tap-tackle Despite its name, a tap tackle is a not actually a tackle as the ball carrier is brought to ground by a form of trip, is not actually held on the ground and may attempt to get up and continue to run. A tap tackle is used when a defending player is unable to get close enough to the ball carrier but is able to dive at the other player's feet and, with outstretched arm, deliver a tap or hook to the player's foot (or feet) causing the player to stumble. At speed, this will often be sufficient to bring the ball-carrier down, allowing a teammate of the tackling player to retrieve the ball or provide sufficient delay for the defending team to organise a defence.Ten Metre Law The Ten Metre Law is a form of offside which is designed to prevent injury to a defending player who attempts to catch a ball that has been kicked ahead by the attacking side.In the normal Law of Offside in open play, it is possible for an offside player to be put onside by actions of the opposing team. This ability to be put onside by a member of the opposing team does not apply if the offside player was within 10 metres along the field of a defending player waiting to catch the ball and the offside player remains offside until either he/she retreats onside or is put onside by a member of their own team.Test match International rugby union matches with full (Test) status are called Test matches.Tight Head The tight head prop is the player who takes the right-hand position on the front row of the scrum. A tight head prop traditionally wears the number 3 shirt. He is named the tight head since in the scrum he will have an opposition player bind to both his left- and right-hand sides, meaning his head is unexposed to the side of the scrum, as opposed to the loose head, whose left-hand side is exposed.TMO Television match official (TMO), commonly called the video referee.Touch Touch is the area outside and including the two touch-lines which define the sides of the playing area. As the touch-lines are not part of the playing area they are part of touch. The ball, and players carrying the ball, are not considered to be in touch until they touch the floor.Touch judge The touch judge is an official who monitors the touch-line and raises a flag if the ball (or player carrying it) goes into touch. Touch judges also stand behind the posts to confirm that a goal has been scored following a penalty kick or conversion of a try.Truck and trailer A colloquial term for an accidental obstruction. "Truck and trailer" occurs when a player carrying the ball leaves a maul, along with one or more of his teammates. Once the ball carrier leaves the maul, the maul is over, and if the ball carrier's teammates are in front of the ball carrier and prevent defending players from making a tackle, the defending team will be awarded a scrum. If the incident of truck and trailer is judged to be deliberate or the latest in a series of similar infringements, a penalty may be awarded instead.
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Glossary of rugby union terms
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T
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Try This is the primary method of scoring. A try is worth five points. It is scored when a player places the ball on the ground with downward pressure in the in-goal area between (and including) the goal-line and up to but not including dead ball line of the opposition's half. (As the goal posts and post protectors are also part of the goal-line, touching the ball down against the base of these is also a try.)There is no such thing as an "own try". If you touch the ball down in your own in-goal area, it results in a goal-line dropout or a five-metre scrum.Tunnel When a scrum is formed, the gap between the legs of the three players from each team who form the 'front row' is called the 'tunnel'.Turnover When a team concedes possession of the ball, particularly at the breakdown, they are said to have turned the ball over to the other team. This can happen due to defending players stealing the ball from an isolated attacker, counter rucking, a knock on, an intercepted pass or the ball not emerging from a maul (wherein the referee awards the scrum feed to the opposing team).Twenty two metre drop-out A drop kick is taken from behind the 22m line if a team touches down in its own in-goal area but did not carry the ball over the try line, or if the ball is kicked over the dead ball line from any other play other than the kick-off.The ball only needs to cross the line, but if it goes directly into touch a scrum is awarded to the receiving team at the centre-point of the 22m line.
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Glossary of rugby union terms
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U
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Uncontested scrum Scrum in which, due to absence of key specialist forwards through injuries or yellow cards, the safety of the scrum cannot be guaranteed. In an uncontested scrum, the players form a scrum but the two teams do not push against each other or compete for possession.Up and under An up and under, or a Garryowen kick, is a high, short punt onto or behind the defending team.Use it or lose it If a maul stops moving forward the referee will often shout "use it or lose it" to the team in possession of the ball. This means they must pass the ball within a five-second time period. If they do not, the referee will call a scrum and the team not in possession at the beginning of the maul will be given the feed.
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Glossary of rugby union terms
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V
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Video Referee Also called TMO (Television Match Official). This is the official who monitors the match in television recorded matches. He is the person who could be called upon by the referee if he is unaware of the outcome of a rugby situation. A good example is a try that is obscured from view i.e. under numerous players.
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Glossary of rugby union terms
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W
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Wheeling A scrum that has rotated through 90 degrees or more is said to have "wheeled". The referee will order the scrum to be reset, with the ball being turned over if the attacking team is deemed to have been deliberately or repeatedly wheeling the scrum.Wing The players wearing shirts numbers 11 and 14 are the left and right wingers. Wingers must be fast runners and agile in order to evade tackles and have excellent ball-handling skills in order to pass and receive the ball at pace.
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Glossary of rugby union terms
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Y
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Yellow Card In International matches, a yellow card is shown to a player who has been cautioned to indicate "temporary suspension" for repeated or deliberate infringements of the rules. The offending player is sent to the “sin bin” for at least 10 minutes while his team must play a man short. A player who is temporarily suspended cannot return to the pitch until the first break in play after his/her 10-minute suspension is completed.In domestic matches, yellow cards are commonly used in exactly the same manner as in International matches but this is not required by regulation so a referee may order the temporary suspension of a player without showing a yellow card.
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Collaboration Data Objects for Windows NT Server
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Collaboration Data Objects for Windows NT Server
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Collaboration Data Objects for Windows NT Server (CDONTS) is a component included with Microsoft's Windows NT and Windows 2000 server products. It facilitates creating and sending e-mail messages from within web application scripts, typically ASP pages. It is implemented as a COM component, and requires a locally installed SMTP server to handle mail delivery.
CDONTS was deprecated in Windows 2000, and removed completely in Windows Server 2003 in favour of a significantly improved interface, Collaboration Data Objects (CDOSYS).
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Dual cone and polar cone
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Dual cone and polar cone
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Dual cone and polar cone are closely related concepts in convex analysis, a branch of mathematics.
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Dual cone and polar cone
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Dual cone
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In a vector space The dual cone C* of a subset C in a linear space X over the reals, e.g. Euclidean space Rn, with dual space X* is the set C∗={y∈X∗:⟨y,x⟩≥0∀x∈C}, where ⟨y,x⟩ is the duality pairing between X and X*, i.e. ⟨y,x⟩=y(x) C* is always a convex cone, even if C is neither convex nor a cone.
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Dual cone and polar cone
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Dual cone
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In a topological vector space If X is a topological vector space over the real or complex numbers, then the dual cone of a subset C ⊆ X is the following set of continuous linear functionals on X: := Re for all x∈C} ,which is the polar of the set -C. No matter what C is, C′ will be a convex cone. If C ⊆ {0} then C′=X′ In a Hilbert space (internal dual cone) Alternatively, many authors define the dual cone in the context of a real Hilbert space (such as Rn equipped with the Euclidean inner product) to be what is sometimes called the internal dual cone.
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Dual cone and polar cone
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Dual cone
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internal := {y∈X:⟨y,x⟩≥0∀x∈C}.
Using this latter definition for C*, we have that when C is a cone, the following properties hold: A non-zero vector y is in C* if and only if both of the following conditions hold:y is a normal at the origin of a hyperplane that supports C.
y and C lie on the same side of that supporting hyperplane.C* is closed and convex.
C1⊆C2 implies C2∗⊆C1∗ If C has nonempty interior, then C* is pointed, i.e. C* contains no line in its entirety.
If C is a cone and the closure of C is pointed, then C* has nonempty interior.
C** is the closure of the smallest convex cone containing C (a consequence of the hyperplane separation theorem)
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Dual cone and polar cone
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Self-dual cones
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A cone C in a vector space X is said to be self-dual if X can be equipped with an inner product ⟨⋅,⋅⟩ such that the internal dual cone relative to this inner product is equal to C. Those authors who define the dual cone as the internal dual cone in a real Hilbert space usually say that a cone is self-dual if it is equal to its internal dual. This is slightly different from the above definition, which permits a change of inner product. For instance, the above definition makes a cone in Rn with ellipsoidal base self-dual, because the inner product can be changed to make the base spherical, and a cone with spherical base in Rn is equal to its internal dual.
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Dual cone and polar cone
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Self-dual cones
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The nonnegative orthant of Rn and the space of all positive semidefinite matrices are self-dual, as are the cones with ellipsoidal base (often called "spherical cones", "Lorentz cones", or sometimes "ice-cream cones"). So are all cones in R3 whose base is the convex hull of a regular polygon with an odd number of vertices. A less regular example is the cone in R3 whose base is the "house": the convex hull of a square and a point outside the square forming an equilateral triangle (of the appropriate height) with one of the sides of the square.
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Dual cone and polar cone
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Polar cone
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For a set C in X, the polar cone of C is the set Co={y∈X∗:⟨y,x⟩≤0∀x∈C}.
It can be seen that the polar cone is equal to the negative of the dual cone, i.e. Co = −C*.
For a closed convex cone C in X, the polar cone is equivalent to the polar set for C.
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Cube attack
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Cube attack
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The cube attack is a method of cryptanalysis applicable to a wide variety of symmetric-key algorithms, published by Itai Dinur and Adi Shamir in a September 2008 preprint.
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Cube attack
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Attack
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A revised version of this preprint was placed online in January 2009, and the paper has also been accepted for presentation at Eurocrypt 2009.
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Cube attack
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Attack
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A cipher is vulnerable if an output bit can be represented as a sufficiently low degree polynomial over GF(2) of key and input bits; in particular, this describes many stream ciphers based on LFSRs. DES and AES are believed to be immune to this attack. It works by summing an output bit value for all possible values of a subset of public input bits, chosen such that the resulting sum is a linear combination of secret bits; repeated application of this technique gives a set of linear relations between secret bits that can be solved to discover these bits. The authors show that if the cipher resembles a random polynomial of sufficiently low degree then such sets of public input bits will exist with high probability, and can be discovered in a precomputation phase by "black box probing" of the relationship between input and output for various choices of public and secret input bits making no use of any other information about the construction of the cipher.
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Cube attack
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Attack
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The paper presents a practical attack, which the authors have implemented and tested, on a stream cipher on which no previous known attack would be effective. Its state is a 10,000 bit LFSR with a secret dense feedback polynomial, which is filtered by an array of 1000 secret 8-bit to 1-bit S-boxes, whose input is based on secret taps into the LFSR state and whose output is XORed together. Each bit in the LFSR is initialized by a different secret dense quadratic polynomial in 10, 000 key and IV bits. The LFSR is clocked a large and secret number of times without producing any outputs, and then only the first output bit for any given IV is made available to the attacker. After a short preprocessing phase in which the attacker can query output bits for a variety of key and IV combinations, only 230 bit operations are required to discover the key for this cipher.
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Cube attack
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Attack
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The authors also claim an attack on a version of Trivium reduced to 735 initialization rounds with complexity 230, and conjecture that these techniques may extend to breaking 1100 of Trivium's 1152 initialization rounds and "maybe even the original cipher". As of December 2008 this is the best attack known against Trivium.
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Cube attack
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Attack
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The attack is, however, embroiled in two separate controversies. Firstly, Daniel J. Bernstein disputes the assertion that no previous attack on the 10,000-bit LFSR-based stream cipher existed, and claims that the attack on reduced-round Trivium "doesn't give any real reason to think that (the full) Trivium can be attacked". He claims that the Cube paper failed to cite an existing paper by Xuejia Lai detailing an attack on ciphers with small-degree polynomials, and that he believes the Cube attack to be merely a reinvention of this existing technique.
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Cube attack
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Attack
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Secondly, Dinur and Shamir credit Michael Vielhaber's "Algebraic IV Differential Attack" (AIDA) as a precursor of the Cube attack. Dinur has stated at Eurocrypt 2009 that Cube generalises and improves upon AIDA. However, Vielhaber contends that the cube attack is no more than his attack under another name.
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Cube attack
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Attack
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It is, however, acknowledged by all parties involved that Cube's use of an efficient linearity test such as the BLR test results in the new attack needing less time than AIDA, although how substantial this particular change is remains in dispute. It is not the only way in which Cube and AIDA differ. Vielhaber claims, for instance, that the linear polynomials in the key bits that are obtained during the attack will be unusually sparse. He has not yet supplied evidence of this, but claims that such evidence will appear in a forthcoming paper by himself entitled "The Algebraic IV Differential Attack: AIDA Attacking the full Trivium". (It is not clear whether this alleged sparsity applies to any ciphers other than Trivium.)
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Trust fall
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Trust fall
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A trust fall is an activity in which a person deliberately falls, trusting the members of a group (spotters) to catch them. It has also at times been considered a popular team-building exercise in corporate training events.
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Trust fall
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Trust fall
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There are many variants of the trust fall. In one type, the group stands in a circle, with one person in the middle with arms folded against his chest and falls in various directions, being pushed by the group back to a standing position before falling again. In another variant, a person stands on an elevated position (such as a stage, stepping stool or tree stump) and relies on multiple people to catch them. This variant is potentially more dangerous and often leads to injuries.The trust fall was a popular activity conducted as a part of corporate team building activities. However, it fell out of favor due to the legal liabilities associated with the trust fall and the fact that it is known to cause traumatic brain injury when the catcher or catchers fail at their task. Furthermore, while the fall may establish trust in the exercise, "there is little evidence that this trust spills over into day-to-day life".
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Protocadherin 19
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Protocadherin 19
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Protocadherin 19 is a protein belonging to the protocadherin family, which is part of the large cadherin superfamily of cell-adhesion proteins. The PCDH19 gene encoding the protein is located on the long arm of the X chromosome.
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Protocadherin 19
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Clinical significance
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Mutations of the PCDH19 gene cause epilepsy-intellectual disability in females. According to a review published in 2021, PCDH19 was one of the six genes most often affected in genetic epilepsies.
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Protocadherin 19
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History
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The PCDH19 gene that encodes the protein was first cloned in 2000 by Nagase et al. In 2008, PCDH19 was identified as the gene responsible for the development of epilepsy-intellectual disability in females, and in the years that have passed since, rare cases were found of males affected by this disease.
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Austrian Centre for Electron Microscopy and Nanoanalysis
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Austrian Centre for Electron Microscopy and Nanoanalysis
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The Austrian Centre for Electron Microscopy and Nanoanalysis (short: FELMI-ZFE) is a cooperation between the Institute of Electron Microscopy and Nanoanalysis (FELMI) of the Graz University of Technology (TUG) and the Graz Centre of Electron Microscopy (ZFE), which is a member of Austrian Cooperative Research (ACR) and run by the non-profit association for the promotion of electron microscopy. It is located at the “Neue Technik Steyrergasse” campus in Graz.
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Austrian Centre for Electron Microscopy and Nanoanalysis
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Austrian Centre for Electron Microscopy and Nanoanalysis
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The FELMI-ZFE is offering both research and services, to interested partners from academia and industry, using advanced electron microscopic methods for both structural and chemical characterization.
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Austrian Centre for Electron Microscopy and Nanoanalysis
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History
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The acquisition process of the first electron microscope of the Graz University of Technology was started by a donation from industry in 1949. The next year a research group, headed by Fritz Grasenick, was established. Finally, the first electron microscope (“Übermikroskop UEM100” by Siemens & Halske) was bought in 1951 and the opening ceremony was attended by Ernst Ruska, Werner Glaser and Otto Wolf. Despite the Graz University of Technology providing rooms and infrastructure, from the very beginning supplementary income from services research provide for industry was necessary to help cover the high operating and investment cost. Due to the larger interest in measurements and the high utilization of the instrument, the group soon need to expand its personal and look to acquire need microscopes. In order to concentrate all funding sources the non-profit association for the promotion of electron microscopy (Verein zur Förderung der Elektronenmikroskopie und Feinstrukturforschung) was founded in 1959 under the direction of the governor of Styria Josef Krainer senior. The Graz Centre of Electron Microscopy (ZFE) was attached to this non-profit. The combined institutions grew over the years, where the combined role of the head of the university institute and the head of the ZFE in one person played a crucial role in the development of a tight interconnection between fundamental research and application. In 2011 the to this date most expansive and impressive acquisition was possible, a at that time worldwide unique STEM. With the ASTEM (Austrian Scanning Transmission Electron Microscope) magnification of more than one million became possible, this enables atomic resolution. In addition, with an investment volume of 4.5 Mio. Euro, the ASTEM was one of the larges scientific infrastructure investments in Austria.
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Austrian Centre for Electron Microscopy and Nanoanalysis
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Organizational structure, Research & Services
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Approximately 50 people work at the FELMI-ZFE with the number varying somewhat due to dissertations and research projects. In addition roughly 300 scientist visit the FELMI-ZFE each year.
International collaboration There are standing collaboration with approximately 30 research institutes and 140 companies. In addition, since the establishment of the ASTEM, the FELMI-ZFE is part of ESTEEM3 (Enabling Science and Technology through European Electron Microscopy), which is a network of 14 electron microscopy institutes in Europe.
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Austrian Centre for Electron Microscopy and Nanoanalysis
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Organizational structure, Research & Services
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Research & Services Five groups work on four main topics of research: Nanoanalytic of materials Functional Nanostructuring 3D and in situ measurements Polymers and biological materials Instruments Scanning electron microscopy (SEM) Transmission electron microscopy (TEM) Infrared- and Raman-microscopy (IR/Raman) Focused-Ion-Beam-Microscopy (FIB) Atomic forces microscopy (AFM) X-ray diffraction (XRD) Sample preparation Teaching and Education In the academic year 2019/2020 approximately 600 students visited lectures and lab exercises of the Institute of Electron Microscopy and Nanoanalysis. The courses offered are on the topics of fundamental physics, material analysis, electron microscopy and nano-manufacturing. In addition apprenticeships for both lab-technician and media technology are offered.
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Food group
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Food group
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A food group is a collection of foods that share similar nutritional properties or biological classifications. List of nutrition guides typically divide foods into food groups and Recommended Dietary Allowance recommend daily servings of each group for a healthy diet. In the United States for instance, USDA has described food as being in from 4 to 11 different groups.
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Food group
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Historical food groups
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The USDA promoted eight basic food groups prior to 1943, then seven basic food groups until 1956, then four food groups. A food pyramid was introduced in 1992, then MyPyramid in 2005, followed by MyPlate in 2011. Dietary guidelines were introduced in 2015 and slated to be rereleased every five years. The 2020 guidelines were to be released in Spring 2020.
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Food group
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The most common food groups
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Dairy, also called milk products and sometimes categorized with milk alternatives or meat, is typically a smaller category in nutrition guides, if present at all, and is sometimes listed apart from other food groups. Examples of dairy products include milk, butter, ghee, yogurt, cheese, cream and ice cream. The categorization of dairy as a food group with recommended daily servings has been criticized by, for example, the Harvard School of Public Health who point out that "research has shown little benefit, and considerable potential for harm, of such high dairy intakes. Moderate consumption of milk or other dairy products—one to two servings a day—is fine, and likely has some benefits for children. But it’s not essential for adults, for a host of reasons." Fruits, sometimes categorized with vegetables, include apples, oranges, bananas, berries and lemons. Fruits contain carbohydrates, mostly in the form of sugar as well as important vitamins and minerals.
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Food group
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The most common food groups
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Cereals and legumes, sometimes categorized as grains, is often the largest category in nutrition guides. Cereal examples include wheat, rice, oats, barley, bread and pasta. Legumes are also known as pulses and include beans, soy beans, lentils and chickpeas. Cereals are a good source of starch and are often categorized with other starchy food such as potatoes. Legumes are good source of essential amino acids as well as carbohydrates.
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Food group
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The most common food groups
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Meat, sometimes labelled protein and occasionally inclusive of legumes and beans, eggs, meat analogues and/or dairy, is typically a medium- to smaller-sized category in nutrition guides. Examples include chicken, fish, turkey, pork and beef.
Confections, also called sugary foods and sometimes categorized with fats and oils, is typically a very small category in nutrition guides, if present at all, and is sometimes listed apart from other food groups. Examples include candy, soft drinks, and chocolate.
Vegetables, sometimes categorized with fruit and occasionally inclusive of legumes, is typically a large category second only to grains, or sometimes equal or superior to grains, in nutrition guides. Examples include spinach, carrots, onions, and broccoli.
Water is treated in very different ways by different food guides. Some exclude the category, others list it separately from other food groups, and yet others make it the center or foundation of the guide. Water is sometimes categorized with tea, fruit juice, vegetable juice and even soup, and is typically recommended in plentiful amounts.
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Food group
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Uncommon food groups
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The number of "common" food groups varies depending on who is defining them. Canada's Food Guide, which has been in continual publication since 1942 and is the second most requested government document after the income tax form in Canada, recognizes only four official food groups, listing the remainder of foods as "another". Some of these "others" include: Alcoholic beverage or Alcohol is listed apart from other food groups and recommended only for certain people in moderation by Harvard's Healthy Eating Pyramid and the University of Michigan's Healing Foods Pyramid, while Italy's food pyramid includes a half-serving of wine and beer.
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AMPTE-IRM
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AMPTE-IRM
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AMPTE-IRM, also called as AMPTE-Ion Release Module, was a Germany satellite designed and tasked to study the magnetosphere of Earth, being launched as part of the Explorer program. The AMPTE (Active Magnetospheric Particle Tracer Explorers) mission was designed to study the access of solar wind ions to the magnetosphere, the convective-diffusive transport and energization of magnetospheric particles, and the interactions of plasmas in space.
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AMPTE-IRM
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Mission
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The AMPTE-IRM is one of the three components of the international space mission AMPTE, which also included AMPTE-CCE (Charge Composition Explorer), designed by NASA, and AMPTE-UKS (United Kingsom Subsatellite), provided by the United Kingdom.
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AMPTE-IRM
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Spacecraft
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The program consisted of three spacecraft: the AMPTE-CCE, which measured in the magnetosphere the ions released by the AMPTE-IRM; and the AMPTE-UKS, which used thrusters to keep station near the AMPTE-IRM to provide two-point local measurements. The AMPTE-IRM provided multiple ion releases in the solar wind, the magnetosheath, and the magnetotail, with in situ diagnostics of each. The AMPTE-IRM spacecraft was spin-stabilized at 15 rpm. Its spin axis was initially in the ecliptic plane, but later it was adjusted with magnetic torqueing to be at right angles to the ecliptic. The power system was a 60 watts solar array with redundant batteries. There was a redundant S-band telemetry and telecommand system. Telemetry rates could be chosen between 1 and 8 kbps. For injection into the final orbit, the AMPTE-IRM carried its own kick stage. In addition to the ion releases, the instruments on board the spacecraft monitored the ambient, magnetosphere, but with the data acquisition confined to the passes that could be tracked in real time from Germany.
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AMPTE-IRM
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Launch
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AMPTE-IRM was launched with the two other satellites of the AMPTE program on 16 August 1984, at 16:48 UTC, from a Cape Canaveral launch pad by a Delta 3924 launch vehicle.
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AMPTE-IRM
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Experiments
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3-D Plasma Analyzer (30-channel, Electrons: 15 eV-30 keV; Ions: 20 eV/q-40 keV/q) The main instrument consisted of two symmetrical quadrispherical electrostatic analyzers to measure the three-dimensional distributions of electrons and ions, respectively, over 4-pi-sr during every satellite spin period (4 seconds). The energy range covered was 15 eV/Q to 30 keV/Q in 30 channels. The angular resolution was 22.5°. Moments of the measured distributions were directly computed on board. An additional retarding-potential analyzer measured the flux of electrons between approximately 0 and 25 eV.
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AMPTE-IRM
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Experiments
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Ion Release Experiment The experiment consisted of eight lithium and eight barium canisters, which were injected from the AMPTE-IRM in pairs by ground command and ignited 10 minutes after separation from the spacecraft. Each of these was either totally lithium or totally barium. A pair of Li/Ba canisters produced a total of 2.E25/7.E24 Li/Ba atoms, respectively, which were subsequently ionized by solar radiation. Li releases in the solar wind, which were carried out in August/September 1984, were to be followed by an artificial comet release of Ba ions in the dawnside magnetosheath and a number of Ba and Li releases in the geomagnetic tail. In situ diagnostics by AMPTE-IRM and AMPTE-UKS and optical observations of the clouds from the ground were followed by tracing of the ions in the inner magnetosphere by AMPTE-CCE.
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AMPTE-IRM
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Experiments
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Mass Separation Ion Spectrometer (MSIS) (H through Ba: 0.5 eV/q-14 keV/q) The instrument consisted of a retarding-potential analyzer entrance section and a toroidal electrostatic energy-per-charge analyzer, followed by a quadrispherical electrostatic analyzer with superimposed radial magnetic field for mass-per-charge analysis. The energy range covered was approximately 0 to 12 (or 24) keV/Q, with adequate mass resolution to separate the Li and Ba tracer ions. Up to eight different ion species could be analyzed simultaneously.
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AMPTE-IRM
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Experiments
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Plasma Wave Spectrometer (64 channel, E- and B-field, E-: 0.0-5.6 MHz; B-: 30 Hz-1.5 MHz) The instrument used a 42 m (138 ft) tip-to-tip antenna to measure electric fields from DC to 5 MHz and two boom-mounted search coil magnetometers to measure magnetic fields from 30 Hz to 1 MHz. The signals were analyzed by a very low frequency VLF/MF 16-channel spectrum analyzer, three VLF narrow-band swept-frequency receivers, a 60-channel high frequency HF stepped-frequency receiver, and an analog wide-band receiver.
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AMPTE-IRM
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Experiments
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Suprathermal Energy Ionic Charge Analyzer (H through Fe: 5-270 keV/q; electrons: 35-207 keV) The main instrument consisted of a curved plate electrostatic energy-per-charge analyzer followed by a 12 cm (4.7 in) time-of-flight telescope with a thin carbon foil at the front and a solid-state detector at the rear, which measured ion velocity and residual energy. The energy-per-charge range was 10 to 300 keV/Q. The mass resolution, delta M/M, ranged from 0.25 to 0.12. The instrument package also contained an electron sensor for the energy range 35 to 220 keV, provided by University of California, Berkeley.
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AMPTE-IRM
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Experiments
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Triaxial Fluxgate Magnetometer The instrument was a three-axis fluxgate magnetometer mounted on a 2 m (6 ft 7 in) boom. It had two switchable ranges (± 4 microtesla, and ± 60 microtesla) with resolutions of 0.12 and 1.8 nT, respectively and was read out at 32, 16, 8, or 4 vector samples per second, depending on the T/M rate. Signals from each sensor were also fed into four band pass filters with 5.5, 11, 22, and 44-Hz center frequencies and were read out up to two times per second.
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AMPTE-IRM
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End of mission
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The spacecraft became inoperational on 14 August 1986.
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NUN buffer
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NUN buffer
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NUN buffer is a solution that makes it possible to purify proteins located in the nucleus of eukaryotic cells. Although other procedures are available they result in loss of albumin D-box binding protein (DBP) which is unwanted if nuclear signal pathways are to be investigated. Therefore, a new extraction procedure was developed in 1993 to increase recovery of nonhistone proteins using a (NUN) solution containing 0.3 M NaCl, 1 M urea, and 1% nonionic detergent Nonidet P-40, which destabilize salt bridges, hydrogen bonds, and hydrophobic interactions, respectively; resulting in a disruption of interaction between proteins and DNA. By incubating nuclei in NUN buffer and centrifuging the solution, the supernatant will therefore contain nuclear proteins.
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NUN buffer
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NUN buffer
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NUN buffer contains: HEPES [pH 7.6], Urea, NaCl, DDT, PIC 1 & 2, 1.1% NP-40, Sodium orthovanadate, β-glycerol phosphate and water.
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Catastrophic kill
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Catastrophic kill
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A catastrophic kill, K-Kill or complete kill is damage inflicted on an armored vehicle that renders it permanently non-functional (most commonly via fire and/or an explosion).
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Catastrophic kill
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Catastrophic kill
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Among tank crewmen it is also commonly known as a brew-up, coined from the British World War II term for lighting a fire in order to brew tea. The expression arose because British troops used an old petrol tin with holes punched in the side as a makeshift stove on which to brew their tea. The flames licking out of the holes in the side of the tin resembled a burning tank, and thus the expression was coined. Typically, a catastrophic kill results in the ignition of any fuel the vehicle may be carrying as well as the detonation (cooking off, or sympathetic detonation) of its ammunition. A catastrophic kill does not necessarily preclude the survival of the vehicle's crew, although most historical casualties in armored warfare were the result of K-kills. This type of kill is also associated with the jack-in-the-box effect, where a tank's turret is blown skyward due to the overpressure of an ammunition explosion. Some tank designs employ blow-off panels, channeling such explosions outside of the vehicle, turning an otherwise catastrophic kill into a firepower kill.
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Catastrophic kill
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Catastrophic kill
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By contrast, the term knocked out refers to a vehicle which has been damaged to the point of inoperability and abandoned by its crew, but is not obviously beyond the point of repair. A knocked-out vehicle may, however, be later determined to be irreparable and written off.
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Meat on the bone
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Meat on the bone
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Meat on the bone, also called bone-in meat is meat that is sold with some or all of the bones included in the cut or portion, i.e. meat that has not been filleted. The phrase "on the bone" can also be applied to specific types of meat, most commonly ham on the bone, and to fish. Meat or fish on the bone may be cooked and served with the bones still included or the bones may be removed at some stage in the preparation.Examples of meat on the bone include T-bone steaks, chops, spare ribs, chicken leg portions and whole chicken. Examples of fish on the bone include unfilleted plaice and some cuts of salmon.
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Meat on the bone
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Meat on the bone
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Meat on the bone is used in many traditional recipes.
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Meat on the bone
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Effect on flavor and texture
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The principal effect of cooking meat on the bone is that it alters the flavour and texture. Albumen and collagen in the bones release gelatin when boiled which adds substance to stews, stocks, soups and sauces. The bone also conducts heat within the meat so that it cooks more evenly and prevents meat drying out and shrinking during cooking.
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Meat on the bone
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Eating
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Consumption methods vary by size; smaller bones can be eaten whole, while larger ones can be broken or gnawed.
Some meat on the bone is most commonly eaten by picking it up, notably ribs and chicken (particularly wings and drumsticks). Others are primarily eaten by cutting off the meat, such as steaks, but possibly picking up and gnawing the bone when otherwise finished.
Smaller fish are often eaten whole, with the bones. Examples include whitebait of all sorts, anchovies, and smelt. In some cases the bone marrow may also be eaten, notably for beef or poultry (especially chicken), in the later case by the eater breaking or chewing off the end of a soft leg bone and sucking the marrow out.
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Meat on the bone
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Cooking
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Meat on the bone typically cooks slower than boneless meat when roasted in a joint. Individual bone-in portions such as chops also take longer to cook than their filleted equivalents.
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Meat on the bone
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Value for money
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Meat on the bone is quicker and easier to butcher as there is no filleting involved. Filleting is a skilled process that adds to labour and wastage costs as meat remaining on the bones after filleting is of low value (although it can be recovered). As a result, meat on the bone can be better value for money. However, relative value can be hard to judge as the bone part of the product is undesirable in many cultures, for larger bones are inedible. Various portions may contain a greater or lesser proportion of bone.
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Meat on the bone
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Ease of handling
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The presence of bones may make meat products more bulky, irregular in shape, and difficult to pack. Bones may make preparation and carving difficult. However, bones can sometimes be used as handles to make the meat easier to eat.
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Meat on the bone
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Import restrictions
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Foot-and-mouth disease (FMD) is a contagious disease affecting cloven-hoofed animals. Because FMD rarely infects humans but spreads rapidly among animals, it is a much greater threat to the agriculture industry than to human health.
FMD can be contracted by contact with infected meat, with meat on the bone representing a higher risk than filleted meat. As a result, import of meat on the bone remains more restricted than that of filleted meat in many countries.
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Meat on the bone
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Health issues
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Injury Meat and fish served on the bone can present a risk of accident or injury. Small, sharp fish bones are the most likely to cause injury although sharp fragments of meat bone can also cause problems. Typical injuries include bones being swallowed and becoming trapped in the throat, and bones being trapped under the tongue.Discarded bones can also present a risk of injury to pets or wild animals as some types of cooked meat bone break into sharp fragments when chewed.
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Meat on the bone
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Health issues
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BSE Bovine spongiform encephalopathy (BSE), also known as "mad cow disease", is a fatal brain disease affecting cattle. It is believed by most scientists that the disease may be transmitted to human beings who eat the brain or spinal cord of infected carcasses. In humans, it is known as new variant Creutzfeldt–Jakob disease (vCJD or nvCJD), and is also fatal.
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Meat on the bone
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Health issues
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The largest outbreak of BSE was in the United Kingdom, with several other countries affected to a lesser extent. The outbreak started in 1984, and continued into the 1990s, leading to increasing concern among governments and beef consumers as the risk to humans became known, but could not be quantified. Many countries banned or restricted the import of beef products from countries affected by BSE.
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Meat on the bone
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Health issues
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Animal brain and spinal cord had already been removed from the human and animal food chain when, in 1997, prion infection was also detected in the dorsal root ganglia within the spinal column of infected animals. As a result, beef on the bone was banned from sale in the UK as a precaution. This led to criticism that the government was overreacting. The European Union also considered banning beef and lamb on the bone. The UK ban lasted from December 1997 to December 1999, when it was lifted and the risk from beef on the bone declared negligible.
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Meat on the bone
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Use as a metaphor
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The phrase "meat on the bones" is used metaphorically to mean substance. For example, "I expect that we'll start putting some meat on the bones of regulatory reform" indicates an intention to add detail and substance to plans for regulatory reform and implies that these plans were previously only set out in broad or vague terms.
The phrase to "flesh out" relies of the same imagery in which a basic idea is likened to a skeleton or bones and the specific details of the idea to meat or flesh on that skeleton.
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Survivin
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Survivin
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Survivin, also called baculoviral inhibitor of apoptosis repeat-containing 5 or BIRC5, is a protein that, in humans, is encoded by the BIRC5 gene.Survivin is a member of the inhibitor of apoptosis (IAP) family. The survivin protein functions to inhibit caspase activation, thereby leading to negative regulation of apoptosis or programmed cell death. This has been shown by disruption of survivin induction pathways leading to increase in apoptosis and decrease in tumour growth. The survivin protein is expressed highly in most human tumours and fetal tissue, but is completely absent in terminally differentiated cells. These data suggest survivin might provide a new target for cancer therapy that would discriminate between transformed and normal cells. Survivin expression is also highly regulated by the cell cycle and is only expressed in the G2-M phase. It is known that Survivin localizes to the mitotic spindle by interaction with tubulin during mitosis and may play a contributing role in regulating mitosis. The molecular mechanisms of survivin regulation are still not well understood, but regulation of survivin seems to be linked to the p53 protein. It also is a direct target gene of the Wnt pathway and is upregulated by beta-catenin.
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Survivin
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IAP family of anti-apoptotic proteins
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Survivin is a member of the IAP family of antiapoptotic proteins. It is shown to be conserved in function across evolution as homologues of the protein are found both in vertebrates and invertebrates. The first members of the IAPs identified were from the baculovirus IAPs, Cp-IAP and Op-IAP, which bind to and inhibit caspases as a mechanism that contributes to its efficient infection and replication cycle in the host. Later, five more human IAPs that included XIAP, c-IAPl, C-IAP2, NAIP, and survivin were discovered. Survivin, like the others, was discovered by its structural homology to IAP family of proteins in human B-cell lymphoma. The human IAPs, XIAP, c-IAPl, C-IAP2 have been shown to bind to caspase-3 and -7, which are the effector caspases in the signaling pathway of apoptosis. It is not known with absolute certainty though, how the IAPs inhibit apoptosis mechanistically at the molecular level.
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Survivin
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IAP family of anti-apoptotic proteins
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A common feature that is present in all IAPs in the presence of a BIR (Baculovirus IAP Repeat, a ~70 amino acid motif) in one to three copies. It was shown by Tamm et al. that knocking out BIR2 from XIAP was enough to cause a loss of function in terms of XIAPs ability to inhibit caspases. This gives the implication that it is within these BIR motifs that contains the anti-apoptotic function of these IAPs. Survivin's one BIR domain shows a similar sequence compared to that of XIAP's BIR domains.
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Survivin
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Isoforms
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The single survivin gene can give rise to four different alternatively spliced transcripts: Survivin, which has a three-intron–four-exon structure in both the mouse and human.
Survivin-2B, which has an insertion of an alternative exon 2.
Survivin-Delta-Ex-3, which has exon 3 removed. The removal of exon 3 results in a frame shift that generates a unique carboxyl terminus with a new function. This new function may involve a nuclear localization signal. Moreover, a mitochondrial localization signal is also generated.
Survivin-3B, which has an insertion of an alternative exon 3.
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Survivin
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Structure
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A structural feature common to all IAP family proteins is that they all contain at least one baculoviral IAP repeat (BIR) domain characterized by a conserved zinc-coordinating Cys/His motif at the N-terminal half of the protein.Survivin is distinguished from other IAP family members in that it has only one BIR domain. The mice and human BIR domain of survivin are very similar structurally except for two differences that may affect function variability. The human survivin also contains an elongated C-terminal helix comprising 42 amino acids. Survivin is 16.5 kDa large and is the smallest member of the IAP family.
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Survivin
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Structure
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X-ray crystallography has shown two molecules of human survivin coming together to form a bowtie-shape dimer through a hydrophobic interface. This interface includes N-terminal residues 6-10 just before the BIR domain region and the 10 residue region connecting the BIR domain to the C-terminal helix. The structural integrity of the determined crystal structure of survivin is quite reliable, as physiological conditions were used to obtain the images.
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Survivin
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Function
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Apoptosis Apoptosis, the process of programmed cell death, involves complex signaling pathways and cascades of molecular events. This process is needed for proper development during embryonic and fetal growth where there is destruction and reconstruction of cellular structures. In adult organisms, apoptosis is needed to maintain differentiated tissue by striking the balance between proliferation and cell death. It is known that intracellular proteases called caspases degrade the cellular contents of the cell by proteolysis upon activation of the death pathway.
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Survivin
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Function
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Mammalian cells have two main pathways that lead to apoptosis.
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Survivin
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Function
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1. Extrinsic pathway: Initiated by extrinsic ligands binding to death receptors on the surface of the cell. An example of this is the binding of tumour necrosis factor-alpha (TNF-alpha) to TNF-alpha receptor. An example of a TNF receptor is Fas (CD95), which recruits activator caspases like caspase-8 upon binding TNF at the cell surface. The activation of the initiator caspases then initiates a downstream cascade of events that results in the induction of effector caspases that function in apoptosis.2. Intrinsic pathway: This pathway is initiated by intracellular or environmental stimuli. It is focused on detecting the improper functioning of the mitochondria in the cell and, as a result, activates signaling pathways to commit suicide. The membrane permeability of the mitochondria increases and particular proteins are released into the cytoplasm that facilitates the activation of initiator caspases. The particular protein released from the mitochondria is cytochrome c. Cytochrome c then binds to Apaf-1 in the cytosol and results in the activation of initiator caspase-9. The activation of the initiator caspases then initiates a downstream cascade of events that results in the induction of effector caspases that function in apoptosis.One family of proteins called IAPs plays a role in regulating cell death by inhibiting the process. IAPs like survivin, inhibit apoptosis by physically binding to and inhibiting proper caspase function. The function of IAPs is evolutionarily conserved as Drosophila homologues of IAPs have been shown to be essential for cell survival.IAPs have been implicated in studies to have a regulatory effect on cell division. Yeast cells with knock-outs of certain IAP genes did not show problems associated with cell death, but showed defects in mitosis characterized by improper chromosome segregation or failed cytokinesis.Deletion of particular IAPs does not seem to have a profound effect on the cell-death pathway as there is a redundancy of function by the many IAPs that exist in a cell. They have been implicated, however, to play a role in maintaining an anti-apoptotic environment intracellularly. Changing the expression of particular IAPs has shown an increase in spontaneous cell death induction or increased sensitivity to death stimuli.
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Survivin
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Function
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Mechanism of action Inhibition of Bax and Fas-induced apoptosis Tamm et al. have shown that survivin inhibits both Bax and Fas-induced apoptotic pathways. The experiment involved transfecting HEK 293 cells with a Bax-encoding plasmid, which resulted in an increase in apoptosis (~7 fold) as measured by DAPI staining. They then contransfected the 293 cells with Bax-encoding plasmid and survivin-encoding plasmids. They observed that cells transfected along with the survivin showed a significant decrease in apoptosis (~3 fold). A similar result also showed for cells transfected with the Fas-overexpressing plasmid. Immunoblots were performed and confirmed that survivin does not inhibit by mechanism of preventing Bax or Fas protein from being made into fully functional proteins. Therefore, survivin should be acting somewhere downstream of the Bax or Fas signaling pathway to inhibit apoptosis through these pathways.
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Survivin
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Function
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Interaction with caspase-3 and -7 In this part of the experiment, Tamm et al. transfected 293 cells with survivin and lysed them to obtain cell lysate. The lysates were incubated with different caspase forms and survivin was immunopercipitated with anti-survivin antibody. The idea behind this is that, if survivin binds physically with the caspase it is incubated with, it will be co-precipitated along with the survivin while everything else in the lysate is washed away. The immunoprecipitates were then run on SDS-PAGE and then immunoblotted for detection of the desired caspase. If the caspase of interest was detected, it meant that it was bound to survivin in the immunoprecipitation step implicating that survivin and the particular caspase had bound beforehand. Active caspase-3 and -7 coimmunoprecipitated with survivin. The inactive proforms of caspase-3 and -7 did not bind survivin. Survivin also does not bind to active caspase-8. Caspase-3 and -7 are effector proteases whereas caspase-8 is an initiator caspase that sits more upstream in the apoptotic pathway. These results demonstrate survivin's capability to bind with particular caspases in vitro, but may not necessarily translate over to actual physiological conditions. Later, a 2001 study confirmed that human survivin tightly binds caspase-3 and -7 when expressed in E. coli.Further evidence to support the idea that survivin blocks apoptosis by directly inhibiting caspases was given by Tamm et al. 293 cells were transfected with either overexposed caspase-3 or -7 encoding plasmid and with survivin. They showed that survivin inhibited processing of these two caspases into their active forms. While survivin has been shown as mentioned above to bind to only the active forms of these caspases, it is likely here that survivin inhibits the active forms of the caspases resulting from cleaving and activating more of its own proforms. Thus, survivin acts possibly by preventing such a cascade of cleavage and activation amplification from happening resulting in decreased apoptosis.In similar manner, looking at the mitochondrial pathway of apoptosis, cytochrome c was transiently expressed in 293 cells to look at the inhibitory effects survivin had on this pathway. Although the details are not here, survivin was shown to also inhibit cytochrome c and caspase-8-induced activation of caspases.
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Survivin
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Function
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Regulation of cytokinesis While the mechanism by which survivin may regulate cell mitosis and cytokinesis is not known, the observations made on its localization during mitosis suggests strongly that it is involved in some way in the cytokinetic process.
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Survivin
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Function
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Proliferating Daoy cells were placed on a glass coverslip, fixed and stained with fluorescent antibodies for survivin and alpha-tubulin. Immunoflourescence using confocal microscopy was used to look at the localization of survivin and tubulin during the cell-cycle to look for any patterns of survivin expression. Survivin was absent in interphase, but present in the G2-M phase.During the different stages of mitosis, one could see that survivin follows a certain localization pattern. At prophase and metaphase, survivin is mainly nuclear in location. During prophase, as the chromatin condenses so that it is visible under the microscope, survivin starts to move to the centromeres. At prometaphase when the nuclear membrane dissociates and spindle microtubules cross over the nuclear region, survivin stays put at the centromeres. At metaphase, when the chromosomes align at the middle plate and are pulled with high tension to either pole by the kinetochore attachments, survivin then associates with the kinetochores. At anaphase as separation of the chromatids happens, the kinetochore microtubules shorten as the chromosomes move towards to the spindle poles and survivin also moves along to the midplate. Survivin thus accumulates at the midplate at telophase. Finally, survivin localizes to the midbody at the cleavage furrow.
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Survivin
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Function
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Interaction and localization to the mitochondria It has been shown that survivin can heterodimerize individually with the two splice variants Survivin-2B and survivin-deltaEx3. Evidence of the heterodimerization of survivin splice variants with survivin was shown with co-immunoprecipitation experiments after cotransfection with the respective survivin variants with survivin. To determine the localization of exogenously expressed survivin-2B and survivin-deltaEx3, fusion constructs of the proteins were made with GFP and HcRed respectively and Daoy cells were transfected with the plasmid constructs. Survivin was also tagged with a fluorescent protein. The fusion of the survivin variants with the fluorescent molecules allows for simple detection of cellular location by fluorescence microscopy. Survivin-2B by itself, localized to both nuclear and cytoplasmic compartments whereas survivin-deltaEx3 localized only in the nucleus. The localization of the three variants (survivin, Survivin-2B, and survivin-deltaEx3) differ, however, when cotransfected together rather than individually.To see which subcellular compartments contained the survivin splice variants complexes, fluorescent antibody markers for different organelles in the cell were employed. The assumption is that, under fluorescence microscopy, if the particular survivin complex is located in that particular cell compartment, one would observe an overlap from the fluorescence given off by the tagged survivin complex and the tagged compartment as well. Different color fluorescence is used to distinguish compartment from survivin.
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Survivin
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Function
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Endoplasmic reticulum and lyosomes: no colocalization Mitochondria and golgi: both survivin/survivin-2B and survivin/survivin-deltaEx3 colocalizeTo verify these observations, they fractionated the subcellular compartments and performed western blot analysis to definitively say that survivin complexes did indeed localize at these compartments.
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Survivin
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Function
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Role in cancer Expression in different carcinomas Survivin is known to be expressed during fetal development and across most tumour cell types, but is rarely present in normal, non-malignant adult cells. Tamm et al. showed that survivin was expressed in all 60 different human tumour lines used in the National Cancer Institute's cancer drug-screening program, with the highest levels of expression in breast and lung cancer lines and the lowest levels in renal cancers. Knowing the relative expression levels of survivin in different tumour types may prove helpful as survivin-related therapy may be administered depending on the expression level and reliance of the tumour type on survivin for resistance to apoptosis.
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Survivin
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Function
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As an oncogene Survivin can be regarded as an oncogene as its aberrant overexpression in most cancer cells contributes to their resistance to apoptotic stimuli and chemotherapeutic therapies, thus contributing to their ongoing survival.
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Survivin
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Function
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Genomic instability Most human cancers have been found to have gains and losses of chromosomes that may be due to chromosomal instability (CIN). One of the things that cause CIN is the inactivation of genes that control the proper segregation of the sister chromatids during mitosis. In gaining a better understanding of survivin's function in mitotic regulation, scientists have looked into the area of genomic instability. It is known that survivin associates with microtubules of the mitotic spindle at the start of mitosis.It has been shown in the literature that knocking out survivin in cancer cells will disrupt microtubule formation and result in polyploidy as well as massive apoptosis. It has also been shown that survivin-depleted cells exit mitosis without achieving proper chromosome alignment and then reforms single tetraploid nuclei. Further evidence also suggests that survivin is needed for sustaining mitotic arrest upon encounter with mitosis problems. The evidence mentioned above implicates that survivin plays an important regulatory role both in the progression of mitosis and sustaining mitotic arrest. This seems strange, as survivin is known to be highly upregulated in most cancer cells (that usually contain chromosome instability characteristics), and its function is that which promotes proper regulation of mitosis.
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Survivin
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Regulation by p53
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p53 inhibits survivin expression at the transcriptional level Wild-type p53 has been shown to repress survivin expression at the mRNA level. Using an adenovirus vector for wild-type p53, human ovarian cancer cell line 2774qw1 (which expresses mutant p53) was transfected. mRNA levels of survivin were analyzed by real-time quantitative PCR (RT-PCR) and showed time-dependent down regulation of survivin mRNA levels when the cells were infected with wild-type p53. A 3.6 fold decrease of survivin mRNA level was observed 16 hours after infection initiation and decreased 6.7 fold 24 hours after infection. Western blot results do show that there is indeed the p53 from the adenoviral vector was being expressed in the cells using antibody specific for p53. The expression of p53 levels indicative of its role in survivin repression shows that p53 started to be expressed 6 hours into infection and had its highest level at 16–24 hours. To further confirm that endogenous wild-type p53 is really causing the repression of survivin gene expression, the authors induced A549 (human lung cancer cell line with wild-type p53) and T47D (human breast cancer cell line with mutant p53) cells with DNA-damaging agent adriamycin to trigger the physiological p53 apoptotic response in these cancer cells and compare the survivin levels measured to the same cells without DNA damage induction. The A549 line, which intrinsically has functioning wild-type p53, showed significant reduction in survivin levels compared to non-induced cells. This same effect was not seen in T47D cells that carry mutant inactive p53.P53's normal function is to regulate genes that control apoptosis. As survivin is a known inhibitor of apoptosis, it can be implied that p53 repression of survivin is one mechanism by which cells can undergo apoptosis upon induction by apoptotic stimuli or signals. When survivin is over-expressed in the cell lines mentioned in the previous paragraph, apoptotic response from DNA-damaging agent adriamycin decreased in a dose-dependent manner. This suggests that down-regulation of survivin by p53 is important for p53-mediated apoptotic pathway to successfully result in apoptosis. It is known that a defining characteristic of most tumors is the over-expression of survivin and the complete loss of wild-type p53. The evidence put forth by Mirza et al. shows that there exists a link between survivin and p53 that can possibly explain a critical event that contributes to cancer progression.
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Survivin
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Regulation by p53
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p53 suppression of survivin expression In order to see whether p53 re-expression in cancer cells (that have lost p53 expression) has the suppressive effect on the promoter of the survivin gene, a luciferase reporter construct was made. The isolated survivin promoter was placed upstream of the luciferase reporter gene. In a luciferase reporter assay, if the promoter is active, the luciferase gene is transcribed and translated into a product that gives off light that can measured quantitatively and, thus, represents the activity of the promoter. This construct was transfected into cancer cells that had either wild-type or mutant p53. High luciferase activity was measured in the cells with mutant p53 and significantly lower luciferase levels were measured for cells with wild-type p53.Transfection of different cell types with wild-type p53 was associated with a strong repression of the survivin promoter. Transfection with mutant p53 was not shown to strongly repress the survivin promoter. More luciferase constructs were prepared with varying degrees of deletion from the 5' end of the survivin promoter region. At one point, there was deletion that caused the survivin levels to be indifferent to the presence of the p53 over-expression plasmid, indicating that there is a specific region proximal to the transcription start site that is needed for p53 suppression of survivin. Although it has been found that two p53 binding sites are located on the survivin gene promoter, analysis using deletions and mutations has shown that these sites are not essential to transcriptional inactivation.Instead, it is observed that modification of the chromatin inside of the promoter region may be responsible for the transcriptional repression of the survivin gene. This is explained below in the epigenetic regulation section.
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Survivin
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Regulation by p53
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Cell cycle regulation Survivin is shown to be clearly regulated by the cell cycle, as its expression is found to be dominant only in the G2/M phase. This regulation exists at the transcriptional level, as there is evidence of the presence of cell-cycle-dependent element/cell-cycle gene homology region (CDE/CHR)boxes located in the survivin promoter region. Further evidence to support this mechanism of regulation includes the evidence that surivin is poly-ubiquinated and degraded by proteasomes during interphase of the cell cycle. Moreover, survivin has been shown to localize to components of the mitotic spindle during metaphase and anaphase of mitosis. Physical association between polymerized tubulin and survivin have been shown in vitro as well. It is also shown that post-transcriptional modification of survivin involving the phosphorylation of Thr34 leads to increased protein stability in the G2/M phase of the cell cycle.It is known from Mirza et al. that repression of survivin by p53 is not a result of any cell cycle progressive regulation. The same experiment by Mirza et al. with regard to determining p53 suppression of survivin at the transcriptional level was repeated, but this time for cells arrested in different stages of the cell cycle. It was shown that, although p53 arrests the numbers of cells to different extents in different phases, the measured level of survivin mRNA and protein levels were the same across all the samples transfected with the wild-type p53. This shows that p53 acts in a cell-cycle independent manner to inhibit survivin expression.
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Survivin
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Regulation by p53
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Epigenetic and genetic regulation As observed through the literature, survivin is found to be over-expressed across many tumour types. Scientists are not sure of the mechanism that causes this abnormal over-expression of survivin; however, p53 is downregulated in almost all cancers, so it is tempting to suggest that survivin over-expression is due to p53 inactivity. Wagner et al. investigated the possible molecular mechanism involved with the over expression of survivin in acute myeloid leukemia (AML). In their experiments, they did both an epigenetic and a genetic analysis of the survivin gene promoter region in AML patients and compared the observations to what was seen in peripheral blood mononuclear cells (PBMCs) that have been shown to express no survivin. Assuming that the molecular mechanism of survivin re-expression in cancerous cells is at the transcriptional level, the authors decided to look at particular parts of the promoter region of survivin in order to see what happens in cancer cells that does not happen in normal cells that causes such a high level of survivin to be expressed. With regards to an epigenetic mechanism of survivin gene regulation, the authors measured the methylation status of the survivin promoter, since it is accepted that methylation of genes plays an important role in carcinogenesis by silencing of certain genes or vice versa. The authors used methylation specific polymerase chain reaction with bisulfite sequencing methods to measure the promoter methylation status in AML and PBMCs and found unmethylated survivin promoters in both groups. This result shows that DNA methylation status is not an important regulator of survivin re-expression during leukemogenesis. However, De Carvalho et al. performed a DNA methylation screening and identified that DNA methylation of IRAK3 plays a key role in survivin up-regulation in different types of Cancer, suggesting that epigenetic mechanisms plays an indirect role on abnormal over-expression of survivin. With regard to genetic analysis of the survivin promoter region, the isolated DNA of AML and PBMCs were treated with bisulfite, and the survivin promoter region sequence was amplified out with PCR and sequenced to look for any particular genetic changes in the DNA sequence between the two groups. Three single-nucleotide polymorphisms (SNPs) were identified and were all present both in AML patients and in healthy donors. This result suggests that the occurrence of these SNPs in the promoter region of the survivin gene also appears to be of no importance to survivin expression. However, it has not been ruled out yet that there may be other possible epigenetic mechanisms that may be responsible for a high level of survivin expression observed in cancer cells and not in normal cells. For example, the acetylation profile of the survivin promoter region can also be looked at. Different cancer and tissue types may have slight or significant differences in the way survivin expression is regulated in the cell, and, thus, the methylation status or genetic differences in the survivin promoter may be observed to be different in different tissues. Thus, further experiments assessing the epigenetic and genetic profile of different tumour types must be investigated.
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Survivin
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As a drug target
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Expression in cancer as a tool for cancer-directed therapy Survivin is known to be highly expressed in most tumour cell types and absent in normal cells, making it a good target for cancer therapy. The exploitation of survivin's over-active promoter in most cancer cell types allows for the delivery of therapeutics only in cancer cells and removed from normal cells.Small interfering RNA (siRNA) are synthetic antisense oligonucleotides to the mRNA of the gene of interest that works to silence the expression of a particular gene by its complementary binding. siRNAs, such as LY2181308, bound to the respective mRNA results in disruption of translation of that particular gene and thus the absence of that protein in the cell. Thus, the use of siRNAs has great potential to be a human therapeutic, as it can target and silence the expression of potentially any protein you want. A problem arises when siRNA expression in a cell cannot be controlled, allowing its constitutive expression to cause toxic side-effects. With regard to practical treatment of cancer, it is required to either deliver the siRNAs specifically into cancer cells or control the siRNA expression. Previous methods of siRNA therapy employ the use of siRNA sequences cloned into vectors under the control of constitutively active promoters. This causes a problem, as this model is non-specific to cancer cells and damages normal cells too. Knowing that survivin is over-expressed specifically in cancer cells and absent in normal cells, one can imply that the survivin promoter is active only in cancer cells. Thus, the exploitation of this difference between cancer cells and normal cells will allow appropriate therapy directed only at the cells in a patient that are harmful. In an experiment to demonstrate this idea, Trang et al. have created a cancer-specific vector expressing siRNA for green fluorescent protein (GFP) under the human survivin promoter. MCF7 breast cancer cells were cotransfected with this vector and a GFP-expressing vector as well. Their major finding was that MCF7 cells transfected with the siRNA vector for GFP under the survivin promoter had a significant reduction in GFP expression then the cells transfected with the siRNA vector under a cancer non-specific promoter. Moreover, normal non-cancerous cells transfected in the same way mentioned above showed no significant reduction in GFP expression. This is implying that, in normal cells, survivin promoter is not active, and, thus, the siRNA will not be expressed under an inactive survivin promoter.
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