title: Non-player character

text: In early and less advanced RPGs, NPCs only had monologue. Code directs the appearance of a dialogue box, floating text, cutscene, or other means of displaying the NPCs' speech or reaction to the player. NPC speeches of this kind are often designed to give an instant impression of the character of the speaker, providing character vignettes, but they may also advance the story or illuminate the world around the PC. Similar to this is the most common form of storytelling, non-branching dialogue, in which the means of displaying NPC speech are the same as above, but the player character or avatar responds to or initiates speech with NPCs. In addition to the purposes listed above, this enables development of the player character.


title: Non-player character

text: More advanced RPGs feature interactive dialogue, or branching dialogue (dialogue trees). A good example are the games produced by Black Isle Studios and White Wolf, Inc.; every one of their games is multiple-choice roleplaying. When talking to an NPC, the player is presented with a list of dialogue options, and may choose between them. Each choice may result in a different response from the NPC. These choices may affect the course of the game, as well as the conversation. At the least, they provide a reference point to the player of their character's relationship with the game world.


title: Non-player character

text: "Ultima" is an example of a game series that has advanced from non-branching ("Ultima III" and earlier) to branching dialogue (from "Ultima IV" and on). Other role-playing games with branching dialogues include "Cosmic Soldier", "Megami Tensei", "Fire Emblem", "Metal Max", "Langrisser", "SaGa", "Ogre Battle", "Chrono", "Star Ocean", "Sakura Wars", "Mass Effect", "Dragon Age", "Radiant Historia", and several "Dragon Quest" and "Final Fantasy" games.


title: Non-player character

text: Certain video game genres revolve almost entirely around interactions with non-player characters, including visual novels such as "Ace Attorney" and dating sims such as "Tokimeki Memorial", usually featuring complex branching dialogues and often presenting the player's possible responses word-for-word as the player character would say them. Games revolving around relationship-building, including visual novels, dating sims such as "Tokimeki Memorial", and some role-playing games such as "", often give choices that have a different number of associated "mood points" that influence a player character's relationship and future conversations with a non-player character. These games often feature a day-night cycle with a time scheduling system that provides context and relevance to character interactions, allowing players to choose when and if to interact with certain characters, which in turn influences their responses during later conversations.


title: Non-player character

text: On the Internet, NPC is often used as an insult to suggest that some people are unable to form thoughts or opinions of their own. Such people are often characterized as being similar to NPC Wojak, who is a grey-faced, expressionless internet meme.


title: Mister Mxyzptlk

text: Mister Mxyzptlk (, ), sometimes called Mxy, is a character who appears in DC Comics' "Superman" comic books. He is usually presented as a trickster in the classical mythological sense. Mxyzptlk possesses reality-warping powers with which he enjoys tormenting Superman or making life difficult. His portrayal has varied, with him being an outright supervillain in some media, and an antihero in others.


title: Mister Mxyzptlk

text: Mr. Mxyzptlk was created to appear in "Superman" #30 (September / October 1944), in the story "The Mysterious Mr. Mxyztplk" (the original spelling), by writer Jerry Siegel and artist Ira Yarborough. Due to publishing lag time, the character saw print first in the "Superman" daily comic strip by writer Whitney Ellsworth and artist Wayne Boring.


title: Mister Mxyzptlk

text: In most of Mxyzptlk's appearances in DC Comics, he can be stopped only by tricking him into saying or spelling his own name backwards, which will return him to his home in the fifth dimension and keep him there for a minimum of 90 days. This limitation of the character was modified in the 1986 "Crisis on Infinite Earths" reboot, upon which Mxyzptlk changes his condition to leave to a new requirement each story, such as having Superman succeed in getting him to paint his own face blue.


title: Mister Mxyzptlk

text: Mxyzptlk has appeared in various television adaptations of Superman. He appeared in the 1993 television series "", portrayed by Howie Mandel. Mxyzptlk also appeared in the 2001 television series "Smallville" played by Trent Ford. Mxyzptlk appeared in the Arrowverse television series "Supergirl" played by Peter Gadiot in the second season and by Thomas Lennon in the fifth and sixth seasons, while the late comedian Gilbert Gottfried voiced the character in several voice-acting-related projects.


title: Mister Mxyzptlk

text: Mister Mxyztplk (the original spelling) was introduced in the Golden Age as an imp from the "fifth dimension". Not being bound by physical laws, he can do things that seem to be magical. In his first appearance, Mxyztplk wreaks havoc across Metropolis by using his powers to pull all manner of pranks, first pretending he got hit by a truck and killed, then increasing his weight when the ambulance gets there and waking up to shock them. What is more, he destroys Superman's worldview of himself. Mxyztplk jumps out a window, fooling Superman into thinking Mxyztplk is committing suicide. When he appears unharmed, an astonished Superman exclaims, "I-I thought I was the only man who could fly!!". He gives the Mayor the voice of a donkey, then blows papers over the town. Mxyztplk soon tells Superman that he is a jester in his home dimension, explaining why he uses his powers to play practical jokes. But one day he found a book which told him of this world.


title: Mister Mxyzptlk

text: Originally, Mxyztplk has designs on conquering the planet for himself, but soon settles for tormenting Superman whenever he gets the opportunity. His only weaknesses are that he cannot stand being ridiculed and if he says or spells his name backwards, he is involuntarily sent back to his home dimension for a minimum of 90 days. He first gets fooled when Superman asks what the word is and the imp says he can't believe Superman would have thought him stupid enough to say "Klptzyxm"--before realizing what he has just said and being transported home. Mxyztplk often looks for ways to counter the latter weakness, but he always proves gullible enough for Superman to trick him time and time again. In the Golden Age, saying "Klptzyxm" will not only send Mxyztplk back to the fifth dimension, but also anyone else who said it. To return to his/her home dimension, one has to say one's own name backwards.


title: Mister Mxyzptlk

text: Mxyztplk originally appeared as a small bald man in a purple suit, green bow tie, and purple derby hat. This was changed to a futuristic looking orange outfit with purple trim and white hair on the sides of his head in the mid-1950s, although the bowler hat remains adapted to the new color scheme. In "Superman" #131 (1959), the spelling of Mxyztplk's name changed (by some accounts through a mistake) to "Mxyzptlk".


title: Mister Mxyzptlk

text: It was explained in the Silver Age "Superman" comics that Mister Mxyzptlk could affect Superman because Superman is susceptible to magic, which was established as a major weakness for the superhero.


title: Mister Mxyzptlk

text: When a Mxyzptlk jaunt causes a special appearance by Superman to be cancelled and children, who had done nothing to Mxyzptlk, to be disappointed, Superman himself decides to turn the tables and visit the fifth dimension, making trouble for the imp, who is running for mayor. For example, when Mxyzptlk furnishes a huge supply of food for prospective voters, he says, "Eat up, folks, the food's on me!" Superman uses super-breath to blow the food all over the imp and then chortles to the voters, "Like he said, folks – the food is on him!" The imp tries to get the Man of Steel to say "Namrepus" ("Superman" backwards) repeatedly, but when he finally succeeds, it does not work and Superman remains in the fifth dimension. Mxyzptlk ultimately loses the election, and, his mission accomplished, Superman returns to Earth by whispering "Le-Lak" (his Kryptonian birth name Kal-El backwards).


title: Mister Mxyzptlk

text: After the establishment of DC Comics' Multiverse in the 1960s, it was later explained that the purple-suited Mxyztplk lives in the fifth dimension connected to Earth-Two, and the orange-costumed Mxyzptlk in the fifth dimension connected to Earth-One. The Earth-One version is also retconned into Superboy stories as the young red-haired Master Mxyzptlk, who bedevils Superboy during his youth in Smallville. He even appears as a deus ex machina to stop the Kryptonite Kid, who was killing a helpless Superboy, so that he could continue to bedevil Superboy and, later, Superman.


title: Mister Mxyzptlk

text: A 30th-century descendant of Mxyzptlk appeared in "Adventure Comics" #310 (July 1963) with similar abilities. Much crueler than his ancestor, this version kills most of the Legion of Super-Heroes until Superboy tricks him into falling victim to the same "Kltpzyxm" weakness, reversing the effects of his magic. However, in another story from "Adventure Comics" #355 (April 1967) featuring the 30th-century Adult Legion, the brother of the cruel Mxyzptlk teams up with a descendant of Lex Luthor to save the Legionnaires from the Legion of Super-Villains and join the Legion themselves.


title: Mister Mxyzptlk

text: Alan Moore offered a radically different interpretation of the character in the 1986 two-issue story "", a possible end of the adventures of the Earth-One Superman. Mister Mxyzptlk (appearing in darker colors and looking more sinister than in the past) explains that the problem with immortality is finding ways to spend the time. He spent his first 2,000 years without moving or breathing, the next 2,000 years doing only good deeds, and the following 2,000 years being the mischievous character that he is normally portrayed as. He has now decided to try being evil, and is responsible for all of the nightmarish events in the story (also musing that after 2,000 years of evil, he may spend the next 2,000 years feeling guilty). Before attacking Superman, he reveals his true form, which is described by Lois Lane as having "height, width, depth, and a couple of other things". He is killed when Superman sends him to the Phantom Zone at the same time that Mister Mxyzptlk begins an escape to the fifth dimension by saying his name backwards voluntarily, tearing him in two. Despite having recognized that his foe was too dangerous to be stopped any other way, remorse over the killing prompts Superman to drain himself of his powers using .


title: Mister Mxyzptlk

text: Another final appearance of Mister Mxyzptlk was in the final issue of "DC Comics Presents", which shows Jor-El's discovery of the Phantom Zone. By the end of the story, the Phantom Zone, the fifth dimension and the Bizarro World are all destroyed, and Mister Mxyzptlk, infilled by power endowed by a hideously disfigured wizard who was a denizen in the Phantom Zone, is transformed into an entity not even remotely human. He then throws the dead Argo City into Metropolis, littering it with tons of kryptonite and dead Kryptonians, and announces to an exasperated and horrified Superman that this was his last jest, that he will never be able to top it, and so says farewell to Superman.


title: Mister Mxyzptlk

text: Mxyzptlk made it through the Crisis on Infinite Earths relatively unchanged, although the unpleasant nature of his pranks and the psychological effects they have on others is played up more, such as when he animated the "Daily Planet" building heedless of the occupants inside who were being violently thrown around with its movements. He also began smoking cigars, symbolic of his newer, more antagonistic nature. His first appearance in this new continuity saw him initially adopting the guise of "Ben deRoy", an omnipotent mystery man resembling the Beyonder (the former name is an anagram of the latter), who was threatening the Marvel Universe around the same time. He resumed his more familiar appearance when he was confronted by Superman.


title: Mister Mxyzptlk

text: In his first Post-"Crisis" story, Mxyzptlk played the "Name Game" with Superman, with saying or writing his name backwards sending him home. However, in his next appearance, this has no effect; the "condition" that would send him back to the fifth dimension would be anything he stated it to be for the occasion, and the act itself would not banish him, but instead be Mxyzptlk abiding by his own terms. After his first encounter with Lex Luthor taught him how to lie, Mxyzptlk began rigging his contests with false or misleading aspects to make his challenges greater. Ultimately, the stories reverted to Mxyzptlk having to say his name backwards to get him to leave.


title: Mister Mxyzptlk

text: One of Mxyzptlk's most prominent storylines in the new continuity was the "Krisis of the Krimson Kryptonite" storyline, when he provided Lex Luthor with a sample of red kryptonite that took away Superman's powers so long as Luthor never revealed to Superman that Mxyzptlk was involved. Despite Superman's lack of powers, he still risked his life to battle Mammoth and the mad scientist Thaddeus Killgrave. Eventually, the spell was lifted when Luthor told "Clark Kent" where the red kryptonite had come from, believing that he would not be breaking Mxyzptlk's rule about not letting Superman know the truth if he told Kent and Kent told Superman (in a one-page aside in this story, Mister Mxyzptlk is implied to also be the Impossible Man, spending his off-time badgering the Fantastic Four of the Marvel Universe).


title: Mister Mxyzptlk

text: Many of Mxyzptlk's later stories have a postmodern feel to them, similar to Ambush Bug, as he comments on editorial decisions, clichés of the genre, etc. This was most obvious in "Superman: The Man of Steel" #75, a pastiche of Superman's death in "Superman" (vol. 2) #75, where Mxyzptlk creates a duplicate of Doomsday. The confrontation culminates with Mxyzptlk meeting the Supreme Being, who turns out to be Mike Carlin, the then-editor of the Superman titles, who promptly brings him back to life. Although Mxyzptlk does not appear in Grant Morrison's "JLA", Morrison took advantage of certain similarities to tie Johnny Thunder's Thunderbolt and Aquaman's nemesis Qwsp to the fifth dimension, implying the dimension may be the origin for legends of djinn. This story also saw the first Post-"Crisis" appearance of Mxyzptlk's Earth-One girlfriend, Ms. Gsptlsnz (described as his "quinto-partner"; pronounced Giz-pit-lez-nez or "Gizbie" for short).


title: Mister Mxyzptlk

text: In 2001, DC published "Bizarro Comics" in which Mister Mxyzptlk fought an all-powerful entity named A who is conquering and wrecking dimensional worlds—including the 5th dimension—by use of toys and games. Mxyzptlk retains the services of a version of Bizarro who calls him Greg, and pads the story out by writing and drawing 27 off-beat stories using the DC superheroes, taking 160 pages. Bizarro is in two of them. Also of note is the depiction of Bahdnesian thunderbolts and Zook's species as native to the fifth dimension.


title: Mister Mxyzptlk

text: In "Countdown to Final Crisis", the modern Mxyzptlk claims to have always felt the need for a "public" in the third dimension and that Superman was not his first victim.


title: Mister Mxyzptlk

text: In "Young Justice" #3, Peter David showed Mxyzptlk's origins as a serious-minded researcher, who travels through time, summoned by computer-based occultists. He takes the opportunity to conduct some scholarly studies. He chooses to examine a Halloween party in Happy Harbor, focusing on the results of aging a portion of the teens and causing some of the others to frantically dance out of control. What Mxyzptlk does not know was that Robin, Superboy, and Impulse were hired by the town's adults to chaperone the party. When the boys confront Mxyzptlk, they realize that this was not the same Mxyzptlk whom Superman had regularly faced; indeed, he appears to not have even assumed the name "Mxyzptlk" at this point, regarding it as sounding like something somebody randomly typed (which is, indeed, how the character chose his name in his first Post-"Crisis" appearance). Upon discovering the chaotic future that awaits him, Mxyzptlk declares that he would dedicate his life to learning and knowledge. However, those words led to a shift in time, creating an apocalyptic world everywhere but outside the building where the Halloween party is being held. This is because Mxyzptlk was not left to annoy Superman. To avoid this, Robin, Superboy, and Impulse realize that they need to instill Mxyzptlk with his trademark wacky sense of humor.


title: Mister Mxyzptlk

text: A "Three Stooges" film is uncovered and watched via an old projector. Mxyzptlk is entertained by the comedy in the film, and tries out a Stooge-style poke in the eye on the projectionist Mick Gurk (an homage to the name "McGurk", the name used by Mxyztplk for a statue he animated in his first appearance), finding the slapstick humor to his liking. He promises that, when it is time, he will hassle Superman as he is supposed to, in honor of Superboy, Impulse, Robin, and even Mick Gurk.


title: Mister Mxyzptlk

text: Time is restored to as how it should be...mostly. Outside the civic center is an unexpected Mxyzptlk theme park, the only change to the world.


title: Mister Mxyzptlk

text: However, it appears that Mxyzptlk has forgotten this incident as the years have passed. When confronted by Superboy later on, the imp declares that he had no knowledge of his adventure with Young Justice. Whether or not this is true, or Mxyzptlk was merely playing a trick on the Boy of Steel, is never revealed.


title: Mister Mxyzptlk

text: In "Emperor Joker", a multi-issue story throughout the "Superman" titles, Mxyzptlk has his powers temporarily stolen by the Joker, who then remakes the Earth in his own image. The imp is unable to remember what to do to break the chain of events that daily culminates with Superman being dragged back to Arkham Asylum by Bizarro. Fortunately, Mxyzptlk is able to reveal the truth to Superman, who manages to find the power to break the cycle and defeat the Joker. As the Joker prepares to end existence, Superman realizes that, for all his power, the Joker still cannot erase Batman, as the Joker defines himself by his constant opposition to the Dark Knight, allowing Superman to shatter the Joker's control of reality. However, Mxyzptlk saves some of the Joker's creations and transfers them into the 'real' world, including Scorch, Gorgeous Gilly, the new Bizarro and "Ignition", a black-armored villain who first appeared in the "Emperor Joker" story, but was created by someone else (exactly who has never been revealed).


title: Mister Mxyzptlk

text: It has also been implied that Mxyzptlk sees himself as serving an important purpose, in teaching Superman not to take everything "too" seriously.


title: Mister Mxyzptlk

text: In "Adventures of Superman" #617 (2003), Mxyzptlk is reinvented as fraternal twins with an intense hatred for Superman. Amongst other things, they claim responsibility for the creation of the present-day Persuader. A year later, in "Superman Secret Files and Origins 2004" (2004), he returns to his usual self following a fellow imp in the fifth dimension combining the twins with the classic Mxyzptlk, resulting in his normal form and personality.


title: Mister Mxyzptlk

text: Mxyzptlk formed a significant part of Greg Rucka's "Ruin" storyline in "Adventures of Superman". His appearance here is similar to his Golden Age look, with the addition of a single lock of hair, resembling Superman's S-shaped forelock. This version of Mxyzptlk is less abrasive than he had been previously, and is portrayed as basically on Superman's side. The metafictional aspects of the character were also played up, as he visits the DC Comics offices in the real world, presented as fumetti.


title: Mister Mxyzptlk

text: At the same time, Mxyzptlk appeared in "Superman/Batman" #23, trying to prepare Batman and Superman for the upcoming "Infinite Crisis". The incident features alternate universe versions of Superman, Batman, and Deathstroke the Terminator and implies much chaos that was not shown, such as the planet Mogo visiting Earth to reclaim an old land mass. At the end of this storyline, Mxyzptlk indicates he has erased the knowledge of Superman's identity from Lex Luthor's mind.


title: Mister Mxyzptlk

text: After the fallout of the events of "Day of Vengeance" (and, while not mentioned, the corruption of the fifth dimension as seen in "JSA"), the removal of magic from the Earth leaves Mxyzptlk nearly powerless, wandering the streets of Metropolis and unable to remember how to pronounce the inverse of his name to return him home. Superman attempts to help him, but the two are attacked by the villain Ruin. Ruin attempts to assassinate Superman with kryptonite-based weaponry, but Mxyzptlk pushes Superman out of the way, taking a kryptonite spear to the heart and vanishing. Right before he vanishes, he seems to whisper 'kltpzyxm'.


title: Mister Mxyzptlk

text: "Action Comics Annual" #10 states that Mister Mxyzptlk was last seen 190 days ago and that his name is pronounced "Mix-Yez-Pittle-Ick" (as it was in the 1960s "Superman" CBS-TV cartoon show, mentioned previously).


title: Mister Mxyzptlk

text: Mister Mxyzptlk makes a one-page appearance in "Countdown" #31. On a walk in the fifth dimension with Gsptlsnz and his pet goldfish named Superman, he is grabbed by someone or something unknown, who then disappears with Mxy. It is later revealed in "Countdown" #23, Mxyzptlk was abducted by Superboy-Prime and imprisoned in the Source Wall. Prime has been apparently torturing the imp into helping him bring back his "perfect Earth", i.e. Earth Prime. Mxyzptlk mentions that he has been coming to Earth for centuries, and has been referred to by many names (Loki, Coyote, and Anansi). He is later sent back to his home by Annataz Arataz, the Earth-3 counterpart of Zatanna, whom Prime had also captured. Arriving in the fifth dimension, he proclaims to Gsptlsnz that he has escaped an encounter with "the Beast" (implying that the fifth dimension is aware of Superboy-Prime, who is referred to as a being of pure evil). Knowing that Superboy-Prime will kill every living soul in the fifth dimension to get revenge on him, Mxyzptlk proclaims that their dimension must be sealed off from outsiders immediately and that he can never return to Earth.


title: Mister Mxyzptlk

text: In September 2011, "The New 52" rebooted DC's continuity. In this new timeline, Mxyzptlk's history is revealed as a traveling wizard in the fifth dimension who entertained the King-Thing Brpxz of Zrfff. He did so by making 333 different three-dimensional worlds, and by challenging heroes in each world, with everyone being entertained by the one hero who could win the challenges, Superman. This led to Mxyzptlk becoming the king's favorite entertainer, and winning the love of the king's daughter, Gsptlnz. However, it also caused jealousy in the now-deposed original court magician, Vyndktvx. Vyndktvx eventually went mad and tried to kill Mxyzptlk, only to kill the king instead. The instant of the murder of the king, committed with the Multispear - a hyper-weapon - reflected in the three-dimensional universe Superman inhabits as a lifelong struggle with the five-dimensional being. Mxyzptlk and his beloved wife descended to the three-dimensional universe to aid Superman in his struggle; their mortal forms perished in due time, still in the same instant in the time of their home world. There, even as he was defeated in the three-dimensional universe, Vndyktvx was arrested and imprisoned for the murder. Mxyzptlk became king and lived happily with his wife, the beautiful princess-now-queen, only to grieve as she died giving birth to their children. And so, he became the sad king that one day, the jester Mxyzptlk would come to entertain, and who would be slain by Vndyktvx in an eternal cycle.


title: Mister Mxyzptlk

text: After the "New 52" Superman died and Pre-"52" Superman took his place by the time of the "DC Rebirth" reboot, a mysterious Clark Kent appeared claiming to be the real one. Despite everyone's hesitations and the previous event that outed Clark as Superman, the new Clark had the medical records to match, and when Superman questioned Clark with a telepathic probe, Clark presented a clear history of Clark Kent as a human being who was orphaned at three months old and subsequently adopted by the Kents. Pre-"52" Lois investigates the new Clark more after getting her job back at the "Daily Planet". Clark asks Lois out on a date which she accepts, but on the date, Lois finds that Clark rented the whole place out for the night and proposed to her, scaring her out of the date. He follows Lois to her secret home and finds out about her marriage to Superman and their son, Jonathan. The next day, after spotting Clark, Superman and Lois's house and Jonathan suddenly disappear. They track Clark down to his apartment, where he reveals himself to be the pre-52 Mister Mxyzptlk, who was absent from the "New 52" universe because he was held captive by Mister Oz and used his powers to transform and brainwash himself into believing he was Clark Kent to avoid getting recaptured after escaping. His attacks on Superman are revenge for failing to notice he has been missing and he proceeds to make Lois forget about her own son. As even Lois forgets that Clark and Superman were the same person, Superman agrees to play Mister Mxyzptlk's game to try and win back the 'right' to see his son again, but although Mister Mxyzptlk attempts to change the rules and ensure his victory, Jonathan is able to fight through his Mister Mxyzptlk-created prison with the aid of unspecified spirits that are revealed to be the "New 52" versions of Superman and Lois, culminating in the creation of a new timeline where the essence of the Post-"Flashpoint" Lois and Clark are fused with their Pre-"Flashpoint" selves, so that the history of both worlds can co-exist.


title: Mister Mxyzptlk

text: Mister Mxyzptlk possesses the ability to warp reality, which has been described alternatively as the product of fifth dimensional magic or advanced technology that appears to be magical to third dimensional beings. Attendant with his abilities is the fact that Mxyzptlk himself is not limited by physical laws: he needs no sustenance such as air or water, can exist in any environment, can teleport anywhere, and is not susceptible to physical harm. His only apparent vulnerability is that whenever he speaks his name backwards, he is shunted back to the fifth dimension, and all effects of his magic vanish. This also has occurred with an indirect application of that rule; on one occasion, Mxyzptlk was banished by a backward-played tape recording of his own voice saying his name.


title: Mister Mxyzptlk

text: However, such a banishment is just a temporary deterrent: after 90 days, Mxyzptlk can again visit the third dimension at will. His reality-warping powers exist in the fifth dimension, but he exerts less control compared to the third dimension, due to the presence of other imps with the same powers.


title: Mister Mxyzptlk

text: Though easily the most powerful of Superman's recurring enemies, the scope of Mxyzptlk's true potential is limited by his personality: his gullible nature makes it easy for Superman or other individuals to trick him into saying his name backwards, and he is overall a fun-loving prankster who prefers to use his power for childish mischief and light-hearted harassment rather than malicious destruction or torment. Thus, he is more of an annoyance than a true threat.


title: Mister Mxyzptlk

text: Mxyzptlk appears in ": Year Three". He poses as the Spectre and sides with Superman and explains his motives as wanting to bring "Order" to the world, helping him against Batman's Insurgence and John Constantine's secret machinations. However, many start questioning the Spectre's sanity in following Superman, only to be quickly dealt with. In the ensuing battle against Trigon, it is revealed Mxyzptlk was posing as the Spectre all along (his long exposure to the Spectre's darkness ends up corrupting him, giving him a darker and more insane look). As he battles Trigon the reality around is altered, rendering all nearby superheroes useless. In a final attempt to stop the fierce magical battle, Doctor Fate, with help from Billy Batson, sends both Mxyzptlk, Trigon, and himself into "the Void", a place as close to death as they can be.


title: Mister Mxyzptlk

text: "" (2000) features Mxyzptlk and Bat-Mite in a battle of magic that kills almost the entire DC Universe and other worlds, at which point they laugh and agree to meet again "next Tuesday", thus revealing that the destruction is both temporary and also a regular source of entertainment for the magical pair.


title: Mister Mxyzptlk

text: In "The Brave and the Bold" #11, Superman is confronted with Ultraman, his counterpart from the Antimatter Universe which most famously housed Qward; however, they are interrupted mid-battle by Mixyezpitellik, Mxyzptlk's own Antimatter counterpart. This counterpart does not reside in Qward, but is another inhabitant of the fifth dimension; he loathes being compared to Mxyzptlk, who he refers to as a 'madcap imp'. Just as Ultraman is in every way the opposite of Superman - uncontrolled, violent, and petulant - so is Mixyezpitellik from Mxyzptlk. He appears dressed in a neat suit and carries an umbrella and wears a large fedora rather than the clownish bowler, though it is still colored purple like that of his counterpart, and refers to himself as 'a vowelled Knight of Order', suggesting that the use of vowels in the fifth dimension denotes rank. Notably, Mixyezpitellik specifically states his powers are magic-based and thus limited to some degree, as indicated by him being changed by the very nature of the matter-based reality to become more imp-like to fit into its reality structure. Mixyezpitellik's relationship with Ultraman also mirrors that between Mxyzptlk and Superman; while to Superman, Mxyzptlk is merely a mischievous annoyance who rarely makes a great impact upon him, Ultraman finds himself terrified by Mixyezpitellik's power and is thus made to act as his agent.


title: Mister Mxyzptlk

text: Mxyzptlk is the main villain in the miniseries. Here, he is disguised as the principal of Stanhope Boarding School, which Supergirl, Lena Luthor, and Belinda Zee attend. At the end of issue #5, Mxyzptlk and his henchmen (fellow teachers) reveal their true forms while laughing at the chaos they have spawned.


title: Mister Mxyzptlk

text: In the last issue of the series, it is revealed that Mxyzptlk was behind Supergirl's rocket landing in Metropolis, and almost all the catastrophes in the series, hoping to use her emotions to power a machine that would give him an unlimited amount of energy. It is even suggested that he might have been behind the destruction of Krypton in the first place, just to manipulate events to the current point. After being beaten by an omnipotent Supergirl, who is revealed to be the hand Krona saw, he retreats back to the fifth dimension, only to be banished to a two dimensional prison by his own henchmen, as punishment for "breaking the rules of the game".


title: Mister Mxyzptlk

text: Mister Mxyzptlk appears in "Superman and Batman Generations". In 1959 he was pulled from the fifth dimension along with Bat-Mite by the Epsilon Eridanites to help find a hero that would help them defeat the Bortan Empire. Two of their representatives have found two worthy candidates in the form of Superman and Batman, and they wanted Mxyzptlk to test out Bat-Mite's hero Batman to find out his worthiness, while Bat-Mite tested out Mxyzptlk's hero Superman. Eventually Superman brought the whole contest over to Gotham City, having Bat-Mite's monster fight with Mxyzptlk's. Mxyzptlk decided at that point to create one giant tentacled monster to deal with both heroes. However, both Superman and Batman decided to make themselves look like they were totally defeated and destroyed by the monster so that the Epsilon Eridanites would end up choosing both Mxyzptlk and Bat-Mite as their heroes to take care of the Bortan threat, forever removing them from bothering either Superman or Batman ever again.


title: Mister Mxyzptlk

text: Due to the phonetic difficulties in pronouncing a name spelled without vowels such as Mxyzptlk, it has been pronounced in various ways by various sources over the past four decades. On the 1967 Filmation CBS Superman animated series, it was pronounced as "Mix-yez-PITTLE-ik"; sources indicate that was the official DC Comics version of the time, furnished to the show's writers through DC Comics editor/writer E. Nelson Bridwell. During the 1980s, on the "Super Friends" cartoon, produced by Hanna-Barbera, it was approximated as "Mix-ill-plick". "Miks-yez-pit-lik" is actually a general translation and other variations have included "Mix-yez-PIT-lek", "Mix-yez-PIT-ul-ick", and "Mix-yez-pittle-ik". To further complicate matters, Mxyzptlk says himself in the 1990s of "Superman", that his name is pronounced the same as saying the words "mix, yes, spit, lick", even transforming himself into the appropriate illustrations for the words. Clark had pronounced his name as "Mix-ill-plick" before Mxyzptlk popped out of the comic and proceeded to correct him. In his appearance in the "Superman Returns" video game, Mxyzptlk proudly refers to himself as "the one and only Mr. Mix-yiz-SPIT-Lik!, straight from the fifth dimension!" "Miks-il-piti-lik" (with the "i"s pronounced only lightly) was used on "Smallville", all while the original spelling of his name was pronounced "mix-pit-tulk". This has created great confusion and even debate as to how his name is actually to be spoken.


title: Mister Mxyzptlk

text: In "Action Comics Annual" #10 (2007), "Superman's Top 10 Most Wanted" describes Mister Mxyzptlk and provides the pronunciation as "Mix-yez-pittle-ik", exactly like the 1967 animated series. So, phonetically, the pronunciation backwards would be "Kell-tipp-ZEY-skim". Confusingly, the 1967 animated series used the backwards pronunciation "Kulp-ti-mix-im". It is fair to say that producers were free to interpret the name any way they wanted, just as they routinely changed other elements of comic lore to suit their various series.


title: Standing wave

text: In physics, a standing wave, also known as a stationary wave, is a wave that oscillates in time but whose peak amplitude profile does not move in space. The peak amplitude of the wave oscillations at any point in space is constant with respect to time, and the oscillations at different points throughout the wave are in phase. The locations at which the absolute value of the amplitude is minimum are called nodes, and the locations where the absolute value of the amplitude is maximum are called antinodes.


title: Standing wave

text: Standing waves were first noticed by Michael Faraday in 1831. Faraday observed standing waves on the surface of a liquid in a vibrating container. Franz Melde coined the term "standing wave" (German: "stehende Welle" or "Stehwelle") around 1860 and demonstrated the phenomenon in his classic experiment with vibrating strings.


title: Standing wave

text: This phenomenon can occur because the medium is moving in the direction opposite to the movement of the wave, or it can arise in a stationary medium as a result of interference between two waves traveling in opposite directions. The most common cause of standing waves is the phenomenon of resonance, in which standing waves occur inside a resonator due to interference between waves reflected back and forth at the resonator's resonant frequency.


title: Standing wave

text: For waves of equal amplitude traveling in opposing directions, there is on average no net propagation of energy.


title: Standing wave

text: As an example of the first type, under certain meteorological conditions standing waves form in the atmosphere in the lee of mountain ranges. Such waves are often exploited by glider pilots.


title: Standing wave

text: Standing waves and hydraulic jumps also form on fast flowing river rapids and tidal currents such as the Saltstraumen maelstrom. A requirement for this in river currents is a flowing water with shallow depth in which the inertia of the water overcomes its gravity due to the supercritical flow speed (Froude number: 1.7 – 4.5, surpassing 4.5 results in direct standing wave) and is therefore neither significantly slowed down by the obstacle nor pushed to the side. Many standing river waves are popular river surfing breaks.


title: Standing wave

text: As an example of the second type, a "standing wave" in a transmission line is a wave in which the distribution of current, voltage, or field strength is formed by the superposition of two waves of the same frequency propagating in opposite directions. The effect is a series of nodes (zero displacement) and anti-nodes (maximum displacement) at fixed points along the transmission line. Such a standing wave may be formed when a wave is transmitted into one end of a transmission line and is reflected from the other end by an impedance mismatch, "i.e.", discontinuity, such as an open circuit or a short. The failure of the line to transfer power at the standing wave frequency will usually result in attenuation distortion.


title: Standing wave

text: In practice, losses in the transmission line and other components mean that a perfect reflection and a pure standing wave are never achieved. The result is a "partial standing wave", which is a superposition of a standing wave and a traveling wave. The degree to which the wave resembles either a pure standing wave or a pure traveling wave is measured by the standing wave ratio (SWR).


title: Standing wave

text: Another example is standing waves in the open ocean formed by waves with the same wave period moving in opposite directions. These may form near storm centres, or from reflection of a swell at the shore, and are the source of microbaroms and microseisms.


title: Standing wave

text: This section considers representative one- and two-dimensional cases of standing waves. First, an example of an infinite length string shows how identical waves traveling in opposite directions interfere to produce standing waves. Next, two finite length string examples with different boundary conditions demonstrate how the boundary conditions restrict the frequencies that can form standing waves. Next, the example of sound waves in a pipe demonstrates how the same principles can be applied to longitudinal waves with analogous boundary conditions.


title: Standing wave

text: Standing waves can also occur in two- or three-dimensional resonators. With standing waves on two-dimensional membranes such as drumheads, illustrated in the animations above, the nodes become nodal lines, lines on the surface at which there is no movement, that separate regions vibrating with opposite phase. These nodal line patterns are called Chladni figures. In three-dimensional resonators, such as musical instrument sound boxes and microwave cavity resonators, there are nodal surfaces. This section includes a two-dimensional standing wave example with a rectangular boundary to illustrate how to extend the concept to higher dimensions.


title: Standing wave

text: To begin, consider a string of infinite length along the "x"-axis that is free to be stretched transversely in the "y" direction.


title: Standing wave

text: For a harmonic wave traveling to the right along the string, the string's displacement in the "y" direction as a function of position "x" and time "t" is


title: Standing wave

text: For identical right- and left-traveling waves on the same string, the total displacement of the string is the sum of "y" and "y",


title: Standing wave

text: Note that Equation () does not describe a traveling wave. At any position "x", "y"("x","t") simply oscillates in time with an amplitude that varies in the "x"-direction as formula_5. The animation at the beginning of this article depicts what is happening. As the left-traveling blue wave and right-traveling green wave interfere, they form the standing red wave that does not travel and instead oscillates in place.


title: Standing wave

text: Because the string is of infinite length, it has no boundary condition for its displacement at any point along the "x"-axis. As a result, a standing wave can form at any frequency.


title: Standing wave

text: the amplitude is always zero. These locations are called nodes. At locations on the "x"-axis that are "odd" multiples of a quarter wavelength


title: Standing wave

text: the amplitude is maximal, with a value of twice the amplitude of the right- and left-traveling waves that interfere to produce this standing wave pattern. These locations are called anti-nodes. The distance between two consecutive nodes or anti-nodes is half the wavelength, "λ"/2.


title: Standing wave

text: Next, consider a string with fixed ends at and . The string will have some damping as it is stretched by traveling waves, but assume the damping is very small. Suppose that at the fixed end a sinusoidal force is applied that drives the string up and down in the y-direction with a small amplitude at some frequency "f". In this situation, the driving force produces a right-traveling wave. That wave reflects off the right fixed end and travels back to the left, reflects again off the left fixed end and travels back to the right, and so on. Eventually, a steady state is reached where the string has identical right- and left-traveling waves as in the infinite-length case and the power dissipated by damping in the string equals the power supplied by the driving force so the waves have constant amplitude.


title: Standing wave

text: Equation () still describes the standing wave pattern that can form on this string, but now Equation () is subject to boundary conditions where at and because the string is fixed at and because we assume the driving force at the fixed end has small amplitude. Checking the values of "y" at the two ends,


title: Standing wave

text: This boundary condition is in the form of the Sturm–Liouville formulation. The latter boundary condition is satisfied when formula_10. "L" is given, so the boundary condition restricts the wavelength of the standing waves to


title: Standing wave

text: Waves can only form standing waves on this string if they have a wavelength that satisfies this relationship with "L". If waves travel with speed "v" along the string, then equivalently the frequency of the standing waves is restricted to


title: Standing wave

text: The standing wave with oscillates at the fundamental frequency and has a wavelength that is twice the length of the string. Higher integer values of "n" correspond to modes of oscillation called harmonics or overtones. Any standing wave on the string will have "n" + 1 nodes including the fixed ends and "n" anti-nodes.


title: Standing wave

text: To compare this example's nodes to the description of nodes for standing waves in the infinite length string, note that Equation () can be rewritten as


title: Standing wave

text: In this variation of the expression for the wavelength, "n" must be even. Cross multiplying we see that because "L" is a node, it is an "even" multiple of a quarter wavelength,


title: Standing wave

text: This example demonstrates a type of resonance and the frequencies that produce standing waves can be referred to as "resonant frequencies".


title: Standing wave

text: Next, consider the same string of length "L", but this time it is only fixed at . At , the string is free to move in the "y" direction. For example, the string might be tied at to a ring that can slide freely up and down a pole. The string again has small damping and is driven by a small driving force at .


title: Standing wave

text: In this case, Equation () still describes the standing wave pattern that can form on the string, and the string has the same boundary condition of at . However, at where the string can move freely there should be an anti-node with maximal amplitude of "y". Equivalently, this boundary condition of the "free end" can be stated as at , which is in the form of the Sturm–Liouville formulation. The intuition for this boundary condition at is that the motion of the "free end" will follow that of the point to its left.


title: Standing wave

text: This leads to a different set of wavelengths than in the two-fixed-ends example. Here, the wavelength of the standing waves is restricted to


title: Standing wave

text: Note that in this example "n" only takes odd values. Because "L" is an anti-node, it is an "odd" multiple of a quarter wavelength. Thus the fundamental mode in this example only has one quarter of a complete sine cycle–zero at and the first peak at –the first harmonic has three quarters of a complete sine cycle, and so on.


title: Standing wave

text: This example also demonstrates a type of resonance and the frequencies that produce standing waves are called "resonant frequencies".


title: Standing wave

text: Consider a standing wave in a pipe of length "L". The air inside the pipe serves as the medium for longitudinal sound waves traveling to the right or left through the pipe. While the transverse waves on the string from the previous examples vary in their displacement perpendicular to the direction of wave motion, the waves traveling through the air in the pipe vary in terms of their pressure and longitudinal displacement along the direction of wave motion. The wave propagates by alternately compressing and expanding air in segments of the pipe, which displaces the air slightly from its rest position and transfers energy to neighboring segments through the forces exerted by the alternating high and low air pressures. Equations resembling those for the wave on a string can be written for the change in pressure Δ"p" due to a right- or left-traveling wave in the pipe.


title: Standing wave

text: If identical right- and left-traveling waves travel through the pipe, the resulting superposition is described by the sum


title: Standing wave

text: Note that this formula for the pressure is of the same form as Equation (), so a stationary pressure wave forms that is fixed in space and oscillates in time.


title: Standing wave

text: If the end of a pipe is closed, the pressure is maximal since the closed end of the pipe exerts a force that restricts the movement of air. This corresponds to a pressure anti-node (which is a node for molecular motions, because the molecules near the closed end can't move). If the end of the pipe is open, the pressure variations are very small, corresponding to a pressure node (which is an anti-node for molecular motions, because the molecules near the open end can move freely). The exact location of the pressure node at an open end is actually slightly beyond the open end of the pipe, so the effective length of the pipe for the purpose of determining resonant frequencies is slightly longer than its physical length. This difference in length is ignored in this example. In terms of reflections, open ends partially reflect waves back into the pipe, allowing some energy to be released into the outside air. Ideally, closed ends reflect the entire wave back in the other direction.


title: Standing wave

text: First consider a pipe that is open at both ends, for example an open organ pipe or a recorder. Given that the pressure must be zero at both open ends, the boundary conditions are analogous to the string with two fixed ends,


title: Standing wave

text: Next, consider a pipe that is open at (and therefore has a pressure node) and closed at (and therefore has a pressure anti-node). The closed "free end" boundary condition for the pressure at can be stated as , which is in the form of the Sturm–Liouville formulation. The intuition for this boundary condition at is that the pressure of the closed end will follow that of the point to its left. Examples of this setup include a bottle and a clarinet. This pipe has boundary conditions analogous to the string with only one fixed end. Its standing waves have wavelengths restricted to


title: Standing wave

text: Note that for the case where one end is closed, "n" only takes odd values just like in the case of the string fixed at only one end.


title: Standing wave

text: So far, the wave has been written in terms of its pressure as a function of position "x" and time. Alternatively, the wave can be written in terms of its longitudinal displacement of air, where air in a segment of the pipe moves back and forth slightly in the "x"-direction as the pressure varies and waves travel in either or both directions. The change in pressure Δ"p" and longitudinal displacement "s" are related as


title: Standing wave

text: where "ρ" is the density of the air. In terms of longitudinal displacement, closed ends of pipes correspond to nodes since air movement is restricted and open ends correspond to anti-nodes since the air is free to move. A similar, easier to visualize phenomenon occurs in longitudinal waves propagating along a spring.


title: Standing wave

text: We can also consider a pipe that is closed at both ends. In this case, both ends will be pressure anti-nodes or equivalently both ends will be displacement nodes. This example is analogous to the case where both ends are open, except the standing wave pattern has a phase shift along the "x"-direction to shift the location of the nodes and anti-nodes. For example, the longest wavelength that resonates–the fundamental mode–is again twice the length of the pipe, except that the ends of the pipe have pressure anti-nodes instead of pressure nodes. Between the ends there is one pressure node. In the case of two closed ends, the wavelength is again restricted to


title: Standing wave

text: A Rubens tube provides a way to visualize the pressure variations of the standing waves in a tube with two closed ends.


title: Standing wave

text: Next, consider transverse waves that can move along a two dimensional surface within a rectangular boundary of length "L" in the "x"-direction and length "L" in the "y"-direction. Examples of this type of wave are water waves in a pool or waves on a rectangular sheet that has been pulled taut. The waves displace the surface in the "z"-direction, with defined as the height of the surface when it is still.


title: Standing wave

text: This is an eigenvalue problem where the frequencies correspond to eigenvalues that then correspond to frequency-specific modes or eigenfunctions. Specifically, this is a form of the Helmholtz equation and it can be solved using separation of variables. Assume


title: Standing wave

text: This leads to two coupled ordinary differential equations. The "x" term equals a constant with respect to "x" that we can define as


title: Standing wave

text: This "x"-dependence is sinusoidal–recalling Euler's formula–with constants "A" and "B" determined by the boundary conditions. Likewise, the "y" term equals a constant with respect to "y" that we can define as


title: Standing wave

text: Multiplying these functions together and applying the inverse Fourier transform, "z"("x","y","t") is a superposition of modes where each mode is the product of sinusoidal functions for "x", "y", and "t",


title: Standing wave

text: The constants that determine the exact sinusoidal functions depend on the boundary conditions and initial conditions. To see how the boundary conditions apply, consider an example like the sheet that has been pulled taut where "z"("x","y","t") must be zero all around the rectangular boundary. For the "x" dependence, "z"("x","y","t") must vary in a way that it can be zero at both and for all values of "y" and "t". As in the one dimensional example of the string fixed at both ends, the sinusoidal function that satisfies this boundary condition is


title: Standing wave

text: If the initial conditions for "z"("x","y",0) and its time derivative "ż"("x","y",0) are chosen so the "t"-dependence is a cosine function, then standing waves for this system take the form


title: Standing wave

text: So, standing waves inside this fixed rectangular boundary oscillate in time at certain resonant frequencies parameterized by the integers "n" and "m". As they oscillate in time, they do not travel and their spatial variation is sinusoidal in both the "x"- and "y"-directions such that they satisfy the boundary conditions. The fundamental mode, and , has a single antinode in the middle of the rectangle. Varying "n" and "m" gives complicated but predictable two-dimensional patterns of nodes and antinodes inside the rectangle.


title: Standing wave

text: Note from the dispersion relation that in certain situations different modes–meaning different combinations of "n" and "m"–may resonate at the same frequency even though they have different shapes for their "x"- and "y"-dependence. For example if the boundary is square, , the modes and , and , and and all resonate at


title: Standing wave

text: Recalling that "ω" determines the eigenvalue in the Helmholtz equation above, the number of modes corresponding to each frequency relates to the frequency's multiplicity as an eigenvalue.


title: Standing wave

text: If the two oppositely moving traveling waves are not of the same amplitude, they will not cancel completely at the nodes, the points where the waves are 180° out of phase, so the amplitude of the standing wave will not be zero at the nodes, but merely a minimum. Standing wave ratio (SWR) is the ratio of the amplitude at the antinode (maximum) to the amplitude at the node (minimum). A pure standing wave will have an infinite SWR. It will also have a constant phase at any point in space (but it may undergo a 180° inversion every half cycle). A finite, non-zero SWR indicates a wave that is partially stationary and partially travelling. Such waves can be decomposed into a superposition of two waves: a travelling wave component and a stationary wave component. An SWR of one indicates that the wave does not have a stationary component – it is purely a travelling wave, since the ratio of amplitudes is equal to 1.


title: Standing wave

text: A pure standing wave does not transfer energy from the source to the destination. However, the wave is still subject to losses in the medium. Such losses will manifest as a finite SWR, indicating a travelling wave component leaving the source to supply the losses. Even though the SWR is now finite, it may still be the case that no energy reaches the destination because the travelling component is purely supplying the losses. However, in a lossless medium, a finite SWR implies a definite transfer of energy to the destination.


title: Standing wave

text: One easy example to understand standing waves is two people shaking either end of a jump rope. If they shake in sync the rope can form a regular pattern of waves oscillating up and down, with stationary points along the rope where the rope is almost still (nodes) and points where the arc of the rope is maximum (antinodes).


title: Standing wave

text: Standing waves are also observed in physical media such as strings and columns of air. Any waves traveling along the medium will reflect back when they reach the end. This effect is most noticeable in musical instruments where, at various multiples of a vibrating string or air column's natural frequency, a standing wave is created, allowing harmonics to be identified. Nodes occur at fixed ends and anti-nodes at open ends. If fixed at only one end, only odd-numbered harmonics are available. At the open end of a pipe the anti-node will not be exactly at the end as it is altered by its contact with the air and so end correction is used to place it exactly. The density of a string will affect the frequency at which harmonics will be produced; the greater the density the lower the frequency needs to be to produce a standing wave of the same harmonic.


title: Standing wave

text: Standing waves are also observed in optical media such as optical waveguides and optical cavities. Lasers use optical cavities in the form of a pair of facing mirrors, which constitute a Fabry–Pérot interferometer. The gain medium in the cavity (such as a crystal) emits light coherently, exciting standing waves of light in the cavity. The wavelength of light is very short (in the range of nanometers, 10 m) so the standing waves are microscopic in size. One use for standing light waves is to measure small distances, using optical flats.


title: Standing wave

text: Interference between X-ray beams can form an X-ray standing wave (XSW) field. Because of the short wavelength of X-rays (less than 1 nanometer), this phenomenon can be exploited for measuring atomic-scale events at material surfaces. The XSW is generated in the region where an X-ray beam interferes with a diffracted beam from a nearly perfect single crystal surface or a reflection from an X-ray mirror. By tuning the crystal geometry or X-ray wavelength, the XSW can be translated in space, causing a shift in the X-ray fluorescence or photoelectron yield from the atoms near the surface. This shift can be analyzed to pinpoint the location of a particular atomic species relative to the underlying crystal structure or mirror surface. The XSW method has been used to clarify the atomic-scale details of dopants in semiconductors, atomic and molecular adsorption on surfaces, and chemical transformations involved in catalysis.


title: Standing wave

text: Standing waves can be mechanically induced into a solid medium using resonance. One easy to understand example is two people shaking either end of a jump rope. If they shake in sync, the rope will form a regular pattern with nodes and antinodes and appear to be stationary, hence the name standing wave. Similarly a cantilever beam can have a standing wave imposed on it by applying a base excitation. In this case the free end moves the greatest distance laterally compared to any location along the beam. Such a device can be used as a sensor to track changes in frequency or phase of the resonance of the fiber. One application is as a measurement device for dimensional metrology.


title: Standing wave

text: The Faraday wave is a non-linear standing wave at the air-liquid interface induced by hydrodynamic instability. It can be used as a liquid-based template to assemble microscale materials.


title: Dark wave

text: Dark wave (also typeset as darkwave) is a music genre that emerged from the new wave and post-punk movement of the late 1970s. Dark wave compositions are largely based on minor key tonality and introspective lyrics and have been perceived as being dark, romantic and bleak, with an undertone of sorrow. The genre embraces a range of styles including cold wave, ethereal wave, gothic rock, neoclassical dark wave and neofolk.


title: Dark wave

text: In the 1980s, a subculture developed primarily in Europe alongside dark wave music, whose followers were called "wavers" or "dark wavers". In some countries such as Germany, the movement also included fans of gothic rock (so-called "trad-goths").


title: Dark wave

text: Since the 1980s, the term has been used in Europe to describe the gloomy and melancholy variant of new wave and post-punk music. At that time, the term "goth" was inseparably connected with gothic rock, whereas "dark wave" acquired a broader meaning, including music artists that were associated with gothic rock and synthesizer-based new wave music.


title: Dark wave

text: The movement spread internationally, developing such strands as ethereal wave, with bands such as Cocteau Twins, and neoclassical dark wave, initiated by the music of Dead Can Dance and In the Nursery. Simultaneously, different substyles associated with the new wave and dark wave movements started to merge and influence each other.


title: Dark wave

text: German dark wave bands were partially associated with the Neue Deutsche Welle (i.e. German new wave). Other bands, such as Malaria! and the Vyllies, added elements of chanson and cabaret music, which became known as cabaret noir (or "dark cabaret", a term popularized by U.S. dark wave label Projekt Records).


title: Dark wave

text: After the new wave and post-punk movements faded in the mid-1980s, dark wave was renewed as an underground movement. Ataraxia and The Frozen Autumn from Italy, and the French Corpus Delicti also evolved from this movement and became the leading artists of the west Romanesque scene. These bands followed a path based on the new wave and post-punk music of the 1980s.


title: Dark wave

text: At the same time, a number of German artists developed a more theatrical style, interspersed with German poetic, metaphorical lyrics, called Neue Deutsche Todeskunst (literally "New German Death Art"). Other bands combined synthesizers with elements of neofolk and neoclassical dark wave.


title: Dark wave

text: After 1993, in the United States the term dark wave (as the one-word variant 'darkwave') became associated with the Projekt Records label, because it was adopted by label founder Sam Rosenthal after leafing through the pages of German music magazines such as Zillo, and has been used to promote and market artists from German label Hyperium Records in the U.S. (e.g. Chandeen and Love Is Colder Than Death).


title: Dark wave

text: Projekt featured bands such as Lycia, Black Tape for a Blue Girl, and Love Spirals Downwards, some of these characterized by atmospheric guitar and synth-sounds and female vocals. This style took cues from 1980s bands like Cocteau Twins and is often referred to as ethereal dark wave. Projekt has also had a long association with Attrition, who appeared on the label's earliest compilations. Joshua Gunn, a professor of communication studies at Louisiana University, described the U.S. type of dark wave music as


title: Dark wave

text: In the 2010s, a new generation of bands has rekindled the darkwave genre for a new generation of fans. The most prominent of these acts is Boy Harsher, but others include Drab Majesty, Pixel Grip, and Kontravoid. Substance is annual Darkwave and Industrial music festival occurring in Los Angeles which began in the 2010s.


title: Mortgage-backed security

text: A mortgage-backed security (MBS) is a type of asset-backed security (an 'instrument') which is secured by a mortgage or collection of mortgages. The mortgages are aggregated and sold to a group of individuals (a government agency or investment bank) that securitizes, or packages, the loans together into a security that investors can buy. Bonds securitizing mortgages are usually treated as a separate class, termed residential; another class is commercial, depending on whether the underlying asset is mortgages owned by borrowers or assets for commercial purposes ranging from office space to multi-dwelling buildings.


title: Mortgage-backed security

text: The structure of the MBS may be known as "pass-through", where the interest and principal payments from the borrower or homebuyer pass through it to the MBS holder, or it may be more complex, made up of a pool of other MBSs. Other types of MBS include collateralized mortgage obligations (CMOs, often structured as real estate mortgage investment conduits) and collateralized debt obligations (CDOs).


title: Mortgage-backed security

text: A mortgage bond is a bond backed by a pool of mortgages on a real estate asset such as a house. More generally, bonds which are secured by the pledge of specific assets are called mortgage bonds. Mortgage bonds can pay interest in either monthly, quarterly or semiannual periods. The prevalence of mortgage bonds is commonly credited to Mike Vranos.


title: Mortgage-backed security

text: The shares of subprime MBSs issued by various structures, such as CMOs, are not identical but rather issued as tranches (French for "slices"), each with a different level of priority in the debt repayment stream, giving them different levels of risk and reward. Tranches of an MBS—especially the lower-priority, higher-interest tranches—are/were often further repackaged and resold as collateralized debt obligations. These subprime MBSs issued by investment banks were a major issue in the subprime mortgage crisis of 2006–2008.


title: Mortgage-backed security

text: The total face value of an MBS decreases over time, because like mortgages, and unlike bonds, and most other fixed-income securities, the principal in an MBS is not paid back as a single payment to the bond holder at maturity but rather is paid along with the interest in each periodic payment (monthly, quarterly, etc.). This decrease in face value is measured by the MBS's "factor", the percentage of the original "face" that remains to be repaid.


title: Mortgage-backed security

text: In the United States, MBSs may be issued by structures set up by government-sponsored enterprises like Fannie Mae or Freddie Mac, or they can be "private-label", issued by structures set up by investment banks.


title: Mortgage-backed security

text: The process of securitization is complex and depends greatly on the jurisdiction within which the process is conducted. Among other things, securitization distributes risk and permits investors to choose different levels of investment and risk. The basics are:


title: Mortgage-backed security

text: While a residential mortgage-backed security (RMBS) is secured by single-family or two- to four-family real estate, a commercial mortgage-backed security (CMBS) is secured by commercial and multi-family properties, such as apartment buildings, retail or office properties, hotels, schools, industrial properties, and other commercial sites. A CMBS is usually structured as a different type of security than an RMBS.


title: Mortgage-backed security

text: These securitization trusts may be structured by government-sponsored enterprises as well as by private entities that may offer credit enhancement features to mitigate the risk of prepayment and default associated with these mortgages. Since residential mortgage holders in the United States have the option to pay more than the required monthly payment (curtailment) or to pay off the loan in its entirety (prepayment), the monthly cash flow of an MBS is not known in advance, and an MBS therefore presents a risk to investors.


title: Mortgage-backed security

text: In the United States, the most common securitization trusts are sponsored by Fannie Mae and Freddie Mac, US government-sponsored enterprises. Ginnie Mae, a US government-sponsored enterprise backed by the full faith and credit of the US government, guarantees that its investors receive timely payments but buys limited numbers of mortgage notes. Some private institutions also securitize mortgages, known as "private-label" mortgage securities. Issuances of private-label mortgage-backed securities increased dramatically from 2001 to 2007 and then ended abruptly in 2008, when real estate markets began to falter. An example of a private-label issuer is the real estate mortgage investment conduit (REMIC), a tax-structure entity usually used for CMOs; among other things, a REMIC structure avoids so-called double taxation.


title: Mortgage-backed security

text: The securitization of mortgages in the 1970s had the advantage of providing more capital for housing at a time when the demographic bulge of baby boomers created a housing shortage and inflation was undermining a traditional source of housing funding, the savings and loan associations (or thrifts), which were limited to providing uncompetitive 5.75% interest rates on savings accounts and consequently losing savers' money to money market funds. Unlike the traditional localized, inefficient mortgage market where there might be a shortage or surplus of funds at any one time, MBSs were national in scope and regionally diversified. Mortgage backed securities helped move interest rate out of the banking sector and facilitated greater specialization among financial institutions.


title: Mortgage-backed security

text: However, mortgage-backed securities may have "led inexorably to the rise of the subprime industry" and "created hidden, systemic risks". They also "undid the connection between borrowers and lenders". Historically, "less than 2% of people lost their homes to foreclosure", but with securitization, "once a lender sold a mortgage, it no longer had a stake in whether the borrower could make his or her payments."


title: Mortgage-backed security

text: Among the early examples of mortgage-backed securities in the United States were the slave mortgage bonds of the early 18th century and the farm railroad mortgage bonds of the mid-19th century which may have contributed to the panic of 1857. There was also an extensive commercial MBS market in the 1920s.


title: Mortgage-backed security

text: In June 1933, the Glass-Steagall Act was signed into law by President Franklin D. Roosevelt. This legislative initiative separated commercial banking from investment banking, providing safeguards against possible corruption with many types of investment securities (like the MBS). Even though the fixed-rate mortgage didn’t yet exist at this time, the law deemed it illegal for a banking institution to both sponsor debts and design investment vehicles or market-making tools as the selfsame entity. In other words, the Mortgage-Backed Security could probably not have existed at this time (without a little tweaking of the laws).


title: Mortgage-backed security

text: As part of the New Deal following the Great Depression, the US federal government created the Federal Housing Administration (FHA) with the National Housing Act of 1934 to assist in the construction, acquisition, and rehabilitation of residential properties. The FHA helped develop and standardize the fixed-rate mortgage as an alternative to the balloon payment mortgage by insuring them, and helped the mortgage design garner usage.


title: Mortgage-backed security

text: In 1938, the government also created the government-sponsored corporation Fannie Mae to create a liquid secondary market in these mortgages and thereby free up the loan originators to originate more loans, primarily by buying FHA-insured mortgages. As part of the Housing and Urban Development Act of 1968, Fannie Mae was split into the current Fannie Mae and Ginnie Mae to support the FHA-insured mortgages, as well as Veterans Administration (VA) and Farmers Home Administration (FmHA) insured mortgages, with the full faith and credit of the US government. In 1970, the federal government authorized Fannie Mae to purchase private mortgages—that is, those not insured by the FHA, VA, or FmHA, and created Freddie Mac to perform a role similar to that of Fannie Mae. Ginnie Mae does not invest in private mortgages.


title: Mortgage-backed security

text: Ginnie Mae guaranteed the first mortgage pass-through security of an approved lender in 1968. In 1971, Freddie Mac issued its first mortgage pass-through, called a "participation certificate", composed primarily of private mortgages. In 1981, Fannie Mae issued its first mortgage pass-through, called a "mortgage-backed security". In 1983, Freddie Mac issued the first collateralized mortgage obligation.


title: Mortgage-backed security

text: In 1960 the government enacted the Real Estate Investment Trust Act to allow the creation of the real estate investment trust (REIT) to encourage real estate investment, and in 1977 Bank of America issued the first private label pass-through. In 1983 the Federal Reserve Board amended Regulation T to allow broker-dealers to use pass-throughs as margin collateral, equivalent to over-the-counter non-convertible bonds. In 1984 the government passed the Secondary Mortgage Market Enhancement Act to improve the marketability of private label pass-throughs, which declared nationally recognized statistical rating organization AA-rated mortgage-backed securities to be legal investments equivalent to Treasury securities and other federal government bonds for federally chartered banks (such as federal savings banks and federal savings associations), state-chartered financial institutions (such as depository banks and insurance companies) unless overridden by state law before October 1991 (which 21 states did), and Department of Labor–regulated pension funds.


title: Mortgage-backed security

text: The Tax Reform Act of 1986 allowed the creation of the tax-exempt real estate mortgage investment conduit (REMIC) special purpose vehicle for the express purpose of issuing pass-throughs. The Tax Reform Act may have contributed to the savings and loan crisis of the 1980s and 1990s that resulted in the Financial Institutions Reform, Recovery and Enforcement Act of 1989, which dramatically changed the savings and loan industry and its federal regulation, encouraging loan origination.


title: Mortgage-backed security

text: Nevertheless, probably the most influential action that encouraged the subprime mortgage crisis of 2008 (other than the neglectful actions of banking institutions) was the Financial Services Moderation Act (also called the Gramm–Leach–Bliley Act). It was signed into law in 1999 by President Clinton, and allowed sole, in-house creation (by solitary banking institutions) of Mortgage-Backed Securities as investment and derivatives instruments. This legislative decision didn’t just tweak or finesse the preexisting law, it effectively repealed the Glass-Steagall Act of 1933, the only remaining statutory safeguard poised against the ensuing disaster.


title: Mortgage-backed security

text: Low-quality mortgage-backed securities backed by subprime mortgages in the United States caused a crisis that played a major role in the 2007–08 global financial crisis. By 2012 the market for high-quality mortgage-backed securities had recovered and was a profit center for US banks.


title: Mortgage-backed security

text: Most bonds backed by mortgages are classified as an MBS. This can be confusing, because a security derived from an MBS is also called an MBS. To distinguish the basic MBS bond from other mortgage-backed instruments, the qualifier "pass-through" is used, in the same way that "vanilla" designates an option with no special features.


title: Mortgage-backed security

text: These types are not limited to Mortgage Backed Securities. Bonds backed by mortgages but that are not MBSs can also have these subtypes.


title: Mortgage-backed security

text: The secondary mortgage market is the market where a network of lenders sell, and investors buy, existing mortgages or MBS. A large percentage of newly originated mortgages are sold by their originators into this large and liquid market where they are packaged into MBS and sold to public and private investors, including Fannie Mae, Freddie Mac, pension funds, insurance companies, mutual funds and hedge funds.


title: Mortgage-backed security

text: Because of the long-term nature of mortgages, the secondary market is an essential factor in maintaining lender liquidity. The infusion of capital from investors provides mortgage lenders such as banks, thrifts, mortgage bankers and other loan originators with a market for their loans. In addition to providing liquidity and increasing overall efficiency, the secondary market can smooth out geographic credit disparities. However, in some respects, particularly where subprime and other riskier mortgages are involved, the secondary mortgage market may exacerbate certain risks and volatility.


title: Mortgage-backed security

text: TBAs—short for "to-be-announced" securities—involve a special type of trading of mortgage-backed securities. TBAs are the most liquid and important secondary mortgage market, with volume in the trillions of dollars annually. TBAs are traded by MBS traders with notional amounts. There are settlement days when the traders have to make good on their trades. At that time, they choose fractions from various pools to make up their TBA. Only agency mortgage-backed securities trade in the TBA market. "In a TBA transaction, the parties agree on a price for delivering a given volume of Agency Pass-Through Mortgage-Backed Securities at a specified future date. The distinguishing feature of a TBA transaction is that the actual identity of the securities to be delivered at settlement is not specified on the date of execution (“Trade Date”). Instead, the parties to the trade agree on only five general parameters of the securities to be delivered: issuer, mortgage type, term, coupon, and month of settlement."


title: Mortgage-backed security

text: TBAs are critical in determining the ultimate interest rates that mortgage borrowers pay, since mortgage originators can "lock in" rates and use TBAs to hedge their exposure. TBAs are also used to hedge many non-TBA eligible mortgage products, such as hybrid ARMs and non-agency mortgages.


title: Mortgage-backed security

text: In Europe there exists a type of asset-backed bond called a covered bond, commonly known by the German term "Pfandbriefe". Covered bonds were first created in 19th-century Germany when Frankfurter Hypo began issuing mortgage covered bonds. The market has been regulated since the creation of a law governing the securities in Germany in 1900. The key difference between covered bonds and mortgage-backed or asset-backed securities is that banks that make loans and package them into covered bonds keep those loans on their books. This means that when a company with mortgage assets on its books issues the covered bond, its balance sheet grows, which would not occur if it issued an MBS, although it may still guarantee the securities payments.


title: Mortgage-backed security

text: There are many reasons for mortgage originators to finance their activities by issuing mortgage-backed securities. Mortgage-backed securities:


title: Mortgage-backed security

text: The high liquidity of most mortgage-backed securities means that an investor wishing to take a position need not deal with the difficulties of theoretical pricing described below; the price of any bond is essentially quoted at fair value, with a very narrow bid/offer spread.


title: Mortgage-backed security

text: Reasons (other than investment or speculation) for entering the market include the desire to hedge against a drop in prepayment rates (a critical business risk for any company specializing in refinancing).


title: Mortgage-backed security

text: As of the second quarter of 2011, there was about $13.7 trillion in total outstanding US mortgage debt. There were about $8.5 trillion in total US mortgage-related securities. About $7 trillion of that was securitized or guaranteed by government-sponsored enterprises or government agencies, the remaining $1.5 trillion being pooled by private mortgage conduits.


title: Mortgage-backed security

text: The weighted-average maturity (WAM) and weighted average coupon (WAC) are used for valuation of a pass-through MBS, and they form the basis for computing cash flows from that mortgage pass-through. Just as this article describes a bond as a 30-year bond with 6% coupon rate, this article describes a pass-through MBS as a $3 billion pass-through with 6% pass-through rate, a 6.5% WAC, and 340-month WAM. The pass-through rate is different from the WAC; it is the rate that the investor would receive if he/she held this pass-through MBS, and the pass-through rate is almost always less than the WAC. The difference goes to servicing costs (i.e., costs incurred in collecting the loan payments and transferring the payments to the investors.)


title: Mortgage-backed security

text: To illustrate these concepts, consider a mortgage pool with just three mortgage loans that have the following outstanding mortgage balances, mortgage rates, and months remaining to maturity:


title: Mortgage-backed security

text: The "weighted-average maturity" (WAM) of a pass-through MBS is the average of the maturities of the mortgages in the pool, weighted by their balances at the issue of the MBS. Note that this is an average across mortgages, as distinct from concepts such as weighted-average life and duration, which are averages across payments of a single loan.


title: Mortgage-backed security

text: The weightings are computed by dividing each outstanding loan amount by total amount outstanding in the mortgage pool (i.e., $900,000). These amounts are the outstanding amounts at the issuance or initiation of the MBS. The WAM for the above example is computed as follows:


title: Mortgage-backed security

text: The "weighted-average coupon" (WAC) of a pass-through MBS is the average of the coupons of the mortgages in the pool, weighted by their original balances at the issuance of the MBS. For the above example this is:


title: Mortgage-backed security

text: Pricing a "vanilla" corporate bond is based on two sources of uncertainty: default risk (credit risk) and interest rate (IR) exposure. The MBS adds a third risk: early redemption (prepayment). The number of homeowners in residential MBS securitizations who prepay increases when interest rates decrease. One reason for this phenomenon is that homeowners can refinance at a lower fixed interest rate. Commercial MBS often mitigate this risk using call protection.


title: Mortgage-backed security

text: Since these two sources of risk (IR and prepayment) are linked, solving mathematical models of MBS value is a difficult problem in finance. The level of difficulty rises with the complexity of the IR model and the sophistication of the prepayment IR dependence, to the point that no closed-form solution (i.e., one that could be written down) is widely known. In models of this type, numerical methods provide approximate theoretical prices. These are also required in most models that specify the credit risk as a stochastic function with an IR correlation. Practitioners typically use specialised Monte Carlo methods or modified Binomial Tree numerical solutions.


title: Mortgage-backed security

text: Theoretical pricing models must take into account the link between interest rates and loan prepayment speed. Mortgage prepayments are usually made because a home is sold or because the homeowner is refinancing to a new mortgage, presumably with a lower rate or shorter term. Prepayment is classified as a "risk" for the MBS investor despite the fact that they receive the money, because it tends to occur when floating rates drop and the fixed income of the bond would be more valuable (negative convexity). In other words, the proceeds received would need to be reinvested at a lower interest rate. Hence the term "prepayment risk".


title: Mortgage-backed security

text: Professional investors generally use arbitrage-pricing models to value MBS. These models deploy interest rate scenarios consistent with the current yield curve as drivers of the econometric prepayment models that models homeowner behavior as a function of projected mortgage rates. Given the market price, the model produces an option-adjusted spread, a valuation metric that takes into account the risks inherent in these complex securities.


title: Mortgage-backed security

text: There are other drivers of the prepayment function (or prepayment risk), independent of the interest rate, such as:


title: Mortgage-backed security

text: The credit risk of mortgage-backed securities depends on the likelihood of the borrower paying the promised cash flows (principal and interest) on time. The credit rating of MBS is fairly high because:


title: Mortgage-backed security

text: If the MBS was not underwritten by the original real estate and the issuer's guarantee, the rating of the bonds would be much lower. Part of the reason is the expected adverse selection against borrowers with improving credit (from MBSs pooled by initial credit quality) who would have an incentive to refinance (ultimately joining an MBS pool with a higher credit rating).


title: Mortgage-backed security

text: Because of the diversity in MBS types, there is wide variety of pricing sources. In general, the more uniform or liquid the MBS, the greater the transparency or availability of prices. Most traders and money managers use Bloomberg and Intex to analyze MBS pools and more esoteric products such as CDOs, although tools such as Citi's The Yield Book, Barclays POINT, and BlackRock's AnSer are also prevalent across Wall Street, especially for multi–asset class managers. Some institutions have also developed their own proprietary software. Tradeweb is used by the largest bond dealers (the "primaries") to transact round lots ($1 million and larger).


title: Mortgage-backed security

text: Complex structured products tend to trade less frequently and involve more negotiation. Prices for these more complicated MBSs, as well as for CMOs and CDOs, tend to be more subjective, often available only from dealers.


title: Mortgage-backed security

text: For "vanilla" or "generic" 30-year pools (issued by Fannie Mae, Freddie Mac, or Ginnie Mae) with coupons of 3.5%–7%, one can see the prices posted on a TradeWeb screen by the primaries called To Be Allocated (TBA). This is due to the actual pools not being shown. These are forward prices for the next 3 delivery months since pools have not been cut; only the issuing agency, coupon, and dollar amount are revealed. A specific pool whose characteristics are known would usually trade "TBA plus {x} ticks" or a "pay-up", depending on characteristics. These are called "specified pools", since the buyer specifies the pool characteristic he/she is willing to "pay up" for.


title: Mortgage-backed security

text: The price of an MBS pool is influenced by prepayment speed, usually measured in units of CPR or PSA. When a mortgage refinances or the borrower prepays during the month, the prepayment measurement increases.


title: Mortgage-backed security

text: If an investor has acquired a pool at a premium (>100), as is common for higher coupons, then they "are" at risk for prepayment. If the purchase price was 105, the investor loses 5 cents for every dollar prepaid, which may significantly decrease the yield. This is likely to happen as holders of higher-coupon mortgages can have a larger incentive to refinance.


title: Mortgage-backed security

text: Conversely, it may be advantageous to the bondholder for the borrower to prepay if the low-coupon MBS pool was bought at a discount (<100). This is due to the fact that when the borrower pays back the mortgage, he does so at "par". If an investor purchases a bond at 95 cents on the dollar, as the borrower prepays the investor gets the full dollar back, increasing their yield. However, this is less likely to occur, as borrowers with low-coupon mortgages have lower, or no, incentives to refinance.


title: Mortgage-backed security

text: The price of an MBS pool is also influenced by the loan balance. Common specifications for MBS pools are loan amount ranges that each mortgage in the pool must pass. Typically, high-premium (high-coupon) MBSs backed by mortgages with an original loan balance no larger than $85,000 command the largest pay-ups. Even though the borrower is paying an above market yield, he or she is dissuaded from refinancing a small loan balance due to the high fixed cost involved.


title: Mortgage-backed security

text: Low Loan Balance: < $85,000Mid Loan Balance: $85,000–$110,000High Loan Balance: $110,000–$150,000Super High Loan Balance: $150,000–$175,000TBA: > $175,000


title: Mortgage-backed security

text: The plurality of factors makes it difficult to calculate the value of an MBS security. Often market participants do not concur, resulting in large differences in quoted prices for the same instrument. Practitioners constantly try to improve prepayment models and hope to measure values for input variables implied by the market. Varying liquidity premiums for related instruments and changing liquidity over time make this a difficult task. One factor used to express price of an MBS security is the pool factor.


title: Mortgage-backed security

text: One critical component of the securitization system in the US market is the Mortgage Electronic Registration Systems (MERS) created in the 1990s, which created a private system wherein underlying mortgages were assigned and reassigned outside of the traditional county-level recording process. The legitimacy and overall accuracy of this alternative recording system have faced serious challenges with the onset of the mortgage crisis: as the US courts flood with foreclosure cases, the inadequacies of the MERS model are being exposed, and both local and federal governments have begun to take action through suits of their own and the refusal (in some jurisdictions) of the courts to recognize the legal authority of MERS assignments. The assignment of mortgage (deed of trust) and note (obligation to pay the debt) paperwork outside of the traditional US county courts (and without recordation fee payment) is subject to legal challenge. Legal inconsistencies in MERS originally appeared trivial, but they may reflect dysfunctionality in the entire US mortgage securitization industry.


title: Phospholipid

text: Phospholipids, are a class of lipids whose molecule has a hydrophilic "head" containing a phosphate group and two hydrophobic "tails" derived from fatty acids, joined by an alcohol residue (usually a glycerol molecule). Marine phospholipids typically have omega-3 fatty acids EPA and DHA integrated as part of the phospholipid molecule. The phosphate group can be modified with simple organic molecules such as choline, ethanolamine or serine.


title: Phospholipid

text: Phospholipids are a key component of all cell membranes. They can form lipid bilayers because of their amphiphilic characteristic. In eukaryotes, cell membranes also contain another class of lipid, sterol, interspersed among the phospholipids. The combination provides fluidity in two dimensions combined with mechanical strength against rupture. Purified phospholipids are produced commercially and have found applications in nanotechnology and materials science.


title: Phospholipid

text: The first phospholipid identified in 1847 as such in biological tissues was lecithin, or phosphatidylcholine, in the egg yolk of chickens by the French chemist and pharmacist Theodore Nicolas Gobley.


title: Phospholipid

text: The phospholipids are amphiphilic. The hydrophilic end usually contains a negatively charged phosphate group, and the hydrophobic end usually consists of two "tails" that are long fatty acid residues.


title: Phospholipid

text: In aqueous solutions, phospholipids are driven by hydrophobic interactions, which result in the fatty acid tails aggregating to minimize interactions with the water molecules. The result is often a phospholipid bilayer: a membrane that consists of two layers of oppositely oriented phospholipid molecules, with their heads exposed to the liquid on both sides, and with the tails directed into the membrane. That is the dominant structural motif of the membranes of all cells and of some other biological structures, such as vesicles or virus coatings.


title: Phospholipid

text: In biological membranes, the phospholipids often occur with other molecules (e.g., proteins, glycolipids, sterols) in a bilayer such as a cell membrane. Lipid bilayers occur when hydrophobic tails line up against one another, forming a membrane of hydrophilic heads on both sides facing the water.


title: Phospholipid

text: These specific properties allow phospholipids to play an important role in the cell membrane. Their movement can be described by the fluid mosaic model, which describes the membrane as a mosaic of lipid molecules that act as a solvent for all the substances and proteins within it, so proteins and lipid molecules are then free to diffuse laterally through the lipid matrix and migrate over the membrane. Sterols contribute to membrane fluidity by hindering the packing together of phospholipids. However, this model has now been superseded, as through the study of lipid polymorphism it is now known that the behaviour of lipids under physiological (and other) conditions is not simple.


title: Phospholipid

text: Phospholipids have been widely used to prepare liposomal, ethosomal and other nanoformulations of topical, oral and parenteral drugs for differing reasons like improved bio-availability, reduced toxicity and increased permeability across membranes. Liposomes are often composed of phosphatidylcholine-enriched phospholipids and may also contain mixed phospholipid chains with surfactant properties. The ethosomal formulation of ketoconazole using phospholipids is a promising option for transdermal delivery in fungal infections. Advances in phospholipid research lead to exploring these biomolecules and their conformations using lipidomics.


title: Phospholipid

text: Computational simulations of phospholipids are often performed using molecular dynamics with force fields such as GROMOS, CHARMM, or AMBER.


title: Phospholipid

text: Phospholipids are optically highly birefringent, i.e. their refractive index is different along their axis as opposed to perpendicular to it. Measurement of birefringence can be achieved using cross polarisers in a microscope to obtain an image of e.g. vesicle walls or using techniques such as dual polarisation interferometry to quantify lipid order or disruption in supported bilayers.


title: Phospholipid

text: There are no simple methods available for analysis of phospholipids, since the close range of polarity between different phospholipid species makes detection difficult. Oil chemists often use spectroscopy to determine total phosphorus abundance and then calculate approximate mass of phospholipids based on molecular weight of expected fatty acid species. Modern lipid profiling employs more absolute methods of analysis, with NMR spectroscopy, particularly P-NMR, while HPLC-ELSD provides relative values.


title: Phospholipid

text: Phospholipid synthesis occurs in the cytosolic side of ER membrane that is studded with proteins that act in synthesis (GPAT and LPAAT acyl transferases, phosphatase and choline phosphotransferase) and allocation (flippase and floppase). Eventually a vesicle will bud off from the ER containing phospholipids destined for the cytoplasmic cellular membrane on its exterior leaflet and phospholipids destined for the exoplasmic cellular membrane on its inner leaflet.


title: Phospholipid

text: Common sources of industrially produced phospholipids are soya, rapeseed, sunflower, chicken eggs, bovine milk, fish eggs etc. Phospholipids for gene delivery such as distearoylphosphatidylcholine, dioleoyl-3-trimethylammonium propane etc. are produced synthetically. Each source has a unique profile of individual phospholipid species, as well as fatty acids, and consequently differing applications in food, nutrition, pharmaceuticals, cosmetics and drug delivery.


title: Phospholipid

text: Some types of phospholipid can be split to produce products that function as second messengers in signal transduction. Examples include phosphatidylinositol (4,5)-bisphosphate (PIP), that can be split by the enzyme phospholipase C into inositol triphosphate (IP) and diacylglycerol (DAG), which both carry out the functions of the G type of G protein in response to various stimuli and intervene in various processes from long term depression in neurons to leukocyte signal pathways started by chemokine receptors.


title: Phospholipid

text: Phospholipids also intervene in prostaglandin signal pathways as the raw material used by lipase enzymes to produce the prostaglandin precursors. In plants they serve as the raw material to produce jasmonic acid, a plant hormone similar in structure to prostaglandins that mediates defensive responses against pathogens.


title: Phospholipid

text: Phospholipids can act as emulsifiers, enabling oils to form a colloid with water. Phospholipids are one of the components of lecithin, which is found in egg yolks, as well as being extracted from soybeans, and is used as a food additive in many products and can be purchased as a dietary supplement. Lysolecithins are typically used for water–oil emulsions like margarine, due to their higher HLB ratio.


title: Nathaniel Rateliff

text: Nathaniel David Rateliff (born October 7, 1978) is an American singer and songwriter based in Denver, Colorado, whose influences are described as folk, Americana and vintage rhythm & blues. Rateliff has performed with a backing band called the Night Sweats for an R&B side project he formed in 2013. He has released three solo albums, two solo EPs, and one album as Nathaniel Rateliff & the Wheel.


title: Nathaniel Rateliff

text: Rateliff was born in St. Louis, Missouri, on October 7, 1978. He grew up in Hermann, Missouri; learning to play the drums at age seven. As a teenager he taught himself guitar, began writing songs and, at eighteen, moved to Denver.


title: Nathaniel Rateliff

text: In 2002, Rateliff formed Born in the Flood, quickly garnering a large following in Denver and headlining local festivals like the Westword Music Showcase. In February 2007, Born in the Flood released their first full-length album "If This Thing Should Spill". Despite increasing success with Born in the Flood, Rateliff turned down an offer from Roadrunner Records, and shifted his focus to a more stripped-down, solo effort, playing somber, singer-songwriter content under his name and "Nathaniel Rateliff & the Wheel".


title: Nathaniel Rateliff

text: In 2007, while still performing with Born in the Flood, Rateliff began recording and performing more personal, somber content both solo and with BitF bandmate and lifetime collaborator Joseph Pope III (bass/guitar/vibes/organ/harmonica). The project expanded with more live performances, adding Julie Davis (upright bass/vocals), Carrie Beeder (organ/violin), James Han (keys/vibes), and Ben Desoto (drums/flute). Shortly after the breakup of Born in the Flood, Rateliff released "Desire and Dissolving Men" on Public Service Records. Nathaniel Rateliff then released "In Memory of Loss" in the USA on Rounder Records in May 2010, and then in the UK on Decca in March 2011. "In Memory of Loss" was recorded with producer Brian Deck (Iron & Wine). On September 17, 2013, Rateliff released "Falling Faster Than You Can Run" on Mod y Vi Records. On the same day he set out on a tour with The Lumineers and Dr. Dog, in support of the album.