title: Ramakrishna

text: Despite initial reservations, Vivekananda became Ramakrishna's most influential follower, popularizing a modern interpretation of Indian traditions which harmonised Tantra, Yoga and Advaita Vedanta. Vivekananda established the Ramakrishna order, which eventually spread its mission posts throughout the world. Monastic disciples, who renounced their family and became the earliest monks of the Ramakrishna order, included Rakhal Chandra Ghosh (Swami Brahmananda), Kaliprasad Chandra (Swami Abhedananda), Taraknath Ghoshal (Swami Shivananda), Sashibhushan Chakravarty (Swami Ramakrishnananda), Saratchandra Chakravarty (Swami Saradananda), Tulasi Charan Dutta (Swami Nirmalananda), Gangadhar Ghatak (Swami Akhandananda), Hari Prasana (Swami Vijnanananda) Swami Turiyananda and others.


title: Ramakrishna

text: As his name spread, an ever-shifting crowd of all classes and castes visited Ramakrishna. Most of Ramakrishna's prominent disciples came between 1879 and 1885. Apart from the early members who joined the Ramakrishna Order, his chief disciples consisted of:


title: Ramakrishna

text: In preparation for monastic life, Ramakrishna ordered his monastic disciples to beg their food from door to door without distinction of caste. He gave them the saffron robe, the sign of the Sanyasi, and initiated them with "Mantra Deeksha".


title: Ramakrishna

text: In the beginning of 1885 Ramakrishna suffered from clergyman's throat, which gradually developed into throat cancer. He was moved to Shyampukur near Kolkata, where some of the best physicians of the time, including Dr. Mahendralal Sarkar, were engaged. When his condition aggravated, he was relocated to a large garden house at Cossipore on 11 December 1885.


title: Ramakrishna

text: During his last days, he was looked after by his monastic disciples and Sarada Devi. Ramakrishna was advised by the doctors to keep the strictest silence, but ignoring their advice, he incessantly conversed with visitors. According to traditional accounts, before his death, Ramakrishna transferred his spiritual powers to Vivekananda, and assured him of his avataric status. Requesting other monastic disciples to look upon Vivekananda as their leader, Ramakrishna asked Vivekananda to look after the welfare of the disciples, saying, "keep my boys together", and asked him to "teach them".


title: Ramakrishna

text: Ramakrishna's condition gradually worsened, and he died in the early morning hours of 16 August 1886 at the Cossipore garden house. According to his disciples, this was "mahasamadhi". His last word, on one account was "ma", while another states he uttered thrice, the word "Kali", before passing away.


title: Ramakrishna

text: After the death of their master, the monastic disciples led by Vivekananda formed a fellowship at a half-ruined house at Baranagar near the river Ganges, with the financial assistance of the householder disciples. This became the first Math or monastery of the disciples who constituted the first Ramakrishna Order.


title: Ramakrishna

text: Ramakrishna's religious practice and worldview, contained elements of Bhakti, Tantra and Vedanta. Ramakrishna emphasised God-realisation, stating that "To realize God is the one goal in life." Ramakrishna found that Hinduism, Christianity and Islam all move towards the same God or divine, though using different ways: "So many religions, so many paths to reach one and the same goal," namely to experience God or Divine. Ramakrishna further said, "All scriptures - the Vedas, the Puranas, the Tantras - seek Him alone and no one else." The Vedic phrase "Truth is one; only It is called by different names," became a stock phrase to express Ramakrishna's inclusivism.


title: Ramakrishna

text: Ramakrishna preferred "the duality of adoring a Divinity beyond himself to the self-annihilating immersion of nirvikalpa samadhi, and he helped "bring to the realm of Eastern energetics and realization the daemonic celebration that the human is always between a reality it has not yet attained and a reality to which it is no longer limited."


title: Ramakrishna

text: Ramakrishna is quoted in the Nikhilananda Gospel, "The devotee of God wants to eat sugar, and not to become sugar."


title: Ramakrishna

text: Max Müller portrayed Ramakrishna as, "...a Bhakta, a worshipper or lover of the deity, much more than a Gñânin or a knower." Postcolonial literary theorist Gayatri Chakravorty Spivak wrote that Ramakrishna was a "Bengali "bhakta" visionary" and that as a "bhakta", "he turned chiefly towards Kali."


title: Ramakrishna

text: Indologist Heinrich Zimmer was the first Western scholar to interpret Ramakrishna's worship of the Divine Mother as containing specifically Tantric elements. Neeval also argued that tantra played a main role in Ramakrishna's spiritual development.


title: Ramakrishna

text: The principal source for Ramakrishna's teaching is Mahendranath Gupta's "Sri Sri Ramakrishna Kathamrita", which is regarded as a Bengali classic and "the central text of the tradition". Gupta used the pen name "M", as the author of the Gospel. The text was published in five volumes from 1902 to 1932. Based on Gupta's diary notes, each of the five volumes purports to document Ramakrishna's life from 1882 to 1886.


title: Ramakrishna

text: The most popular English translation of the "Kathamrita" is "The Gospel of Sri Ramakrishna" by Swami Nikhilananda. Nikhilananda's translation rearranged the scenes in the five volumes of the "Kathamrita" into a linear sequence. Swami Nikhilananda worked with Margaret Woodrow Wilson, daughter of President Woodrow Wilson, who helped the swami to refine his literary style into "flowing American English". The mystic hymns were rendered into free verse by the American poet John Moffitt. Wilson and American mythology scholar Joseph Campbell helped edit the manuscript. Aldous Huxley wrote in his Forward to the Gospel, "...'M' produced a book unique, so far as my knowledge goes, in the literature of hagiography. Never have the casual and unstudied utterances of a great religious teacher been set down with so minute detail." Philosopher Lex Hixon writes that "The Gospel of Ramakrishna" is "spiritually authentic" and a "powerful rendering of the "Kathamrita"". Malcolm Mclean and Jeffrey Kripal both argue that the translation is unreliable, though Kripal's interpretation is criticized by Hugh Urban.


title: Ramakrishna

text: Ramakrishna's teachings were imparted in rustic Bengali, using stories and parables. These teachings made a powerful impact on Kolkata's intellectuals, despite the fact that his ideas were far removed from issues of modernism or national independence. According to contemporary reports, Ramakrishna's linguistic style was unique, even to those who spoke Bengali. It contained obscure local words and idioms from village Bengali, interspersed with philosophical Sanskrit terms and references to the Vedas, Puranas, and Tantras. For that reason, according to philosopher Lex Hixon, his speeches cannot be literally translated into English or any other language. Scholar Amiya P. Sen argued that certain terms that Ramakrishna may have used only in a metaphysical sense are being improperly invested with new, contemporaneous meanings.


title: Ramakrishna

text: Ramakrishna's primary biographers describe him as talkative. According to the biographers, Ramakrishna would reminisce for hours about his own eventful spiritual life, tell tales, explain Vedantic doctrines with extremely mundane illustrations, raise questions and answer them himself, crack jokes, sing songs, and mimic the ways of all types of worldly people, keeping the visitors enthralled. As an example of Ramakrishna's teachings and fun with his followers, here's a quote about his visit to an exhibition, “I once visited the MUSEUM There was a display of fossils: living animals had turned into stone. Just look at the power of association! Imagine what would happen if you constantly kept the company of the holy.” Mani Mallick replied (laughing): “If you would go there again we could have ten to fifteen more years of spiritual instructions.”


title: Ramakrishna

text: Ramakrishna was skilled with words and had an extraordinary style of preaching and instructing, which may have helped convey his ideas to even the most skeptical temple visitors. His speeches reportedly revealed a sense of joy and fun, but he was not at a loss when debating with intellectual philosophers. Philosopher Arindam Chakrabarti contrasted Ramakrishna's talkativeness with the Buddha's legendary reticence, and compared his teaching style to that of Socrates.


title: Ramakrishna

text: Ramakrishna taught that "yatra jiv tatra Shiv" (wherever there is a living being, there is Shiva). His teaching, "Jive daya noy, Shiv gyane jiv seba" (not kindness to living beings, but serving the living being as Shiva Himself) is considered the inspiration for the philanthropic work carried out by his chief disciple Vivekananda.


title: Ramakrishna

text: In the Kolkata scene of the mid to late nineteenth century, Ramakrishna was opinionated on the subject of Chakri. Chakri can be described as a type of low-paying servitude done by educated men—typically government or commerce-related clerical positions. On a basic level, Ramakrishna saw this system as a corrupt form of European social organisation that forced educated men to be servants not only to their bosses at the office, but also to their wives at home. What Ramakrishna saw as the primary detriment of Chakri, however, was that it forced workers into a rigid, impersonal clock-based time structure. He saw the imposition of strict adherence to each second on the watch as a roadblock to spirituality. Despite this, however, Ramakrishna demonstrated that Bhakti could be practised as an inner retreat to experience solace in the face of Western-style discipline and often discrimination in the workplace.


title: Ramakrishna

text: His spiritual movement indirectly aided nationalism, as it rejected caste distinctions and religious prejudices.


title: Ramakrishna

text: Ramakrishna is considered an important figure in the Bengali Renaissance of 19th–20th century. Several organisations have been established in his name. The Ramakrishna Math and Mission is the main organisation founded by Swami Vivekananda in 1897. The Mission conducts extensive work in health care, disaster relief, rural management, tribal welfare, elementary and higher education. The movement is considered one of the revitalisation movements of India. Amiya Sen writes that Vivekananda's "social service gospel" stemmed from direct inspiration from Ramakrishna and rests substantially on the "liminal quality" of the Master's message.


title: Ramakrishna

text: Other organisations include the Ramakrishna Vedanta Society founded by Swami Abhedananda in 1923, the Ramakrishna Sarada Math founded by a rebel group in 1929, the Ramakrishna Vivekananda Mission formed by Swami Nityananda in 1976, and the Sri Sarada Math and Ramakrishna Sarada Mission founded in 1959 as a sister organisation by the Ramakrishna Math and Mission.


title: Ramakrishna

text: During the 1937 Parliament of Religions, which was held at the Ramakrishna Mission in Calcutta, Tagore acknowledged Ramakrishna as a great saint because


title: Ramakrishna

text: Max Müller, Mahatma Gandhi, Jawaharlal Nehru, Sri Aurobindo, and Leo Tolstoy have acknowledged Ramakrishna's contribution to humanity.


title: Ramakrishna

text: Ramakrishna's influence is also seen in the works of artists such as Franz Dvorak (1862–1927) and Philip Glass.


title: Ramakrishna

text: Vivekananda portrayed Ramakrishna as an Advaita Vedantin. Vivekananda's approach can be located in the historical background of Ramakrishna and Calcutta during the mid-19th century. Neevel notes that the image of Ramakrishna underwent several transformations in the writings of his prominent admirers, who changed the 'religious madman' into a calm and well-behaving proponent of Advaita Vedanta. Narasingha Sil has argued that Vivekananda revised and mythologised Ramakrishna's image after Ramakrishna's death. McDaniel notes that the Ramakrishna Mission is biased towards Advaita Vedanta, and downplays the importance of Shaktism in Ramakrishna's spirituality. Malcolm McLean argued that the Ramakrishna Movement presents "a particular kind of explanation of Ramakrishna, that he was some kind of neo-Vedantist who taught that all religions lead to the same Godhead."


title: Ramakrishna

text: Carl Olson argued that in his presentation of his master, Vivekananda had hid much of Ramakrishna's embarrassing sexual oddities from the public, because he feared that Ramakrishna would be misunderstood. Tyagananda and Vrajaprana argue that Oslon makes his "astonishing claim" based on Kripal's speculations in "Kali's Child", which they argue are unsupported by any of the source texts.


title: Ramakrishna

text: Sumit Sarkar argued that he found in the "Kathamrita" traces of a binary opposition between unlearned oral wisdom and learned literate knowledge. He argues that all of our information about Ramakrishna, a rustic near-illiterate Brahmin, comes from urban "bhadralok" devotees, "...whose texts simultaneously illuminate and transform."


title: Ramakrishna

text: Amiya Prosad Sen criticises Neevel's analysis, and writes that "it is really difficult to separate the Tantrik Ramakrishna from the Vedantic", since Vedanta and Tantra "may appear to be different in some respects", but they also "share some important postulates between them".


title: Ramakrishna

text: From his 10th or 11th year of school, trances became a common part of his life, and by his final years Ramakrishna's samadhi periods occurred almost daily. Early on, these experiences have been interpreted as epileptic seizures, an interpretation which was rejected by Ramakrishna himself.


title: Ramakrishna

text: In 1927 Romain Roland discussed with Sigmund Freud the "oceanic feeling" described by Ramakrishna. Sudhir Kakar (1991), Jeffrey Kripal (1995), and Narasingha Sil (1998), analysed Ramakrishna's mysticism and religious practices using psychoanalysis, arguing that his mystical visions, refusal to comply with ritual copulation in Tantra, "Madhura Bhava", and criticism of "Kamini-Kanchana" (women and gold) reflect homosexuality.


title: Ramakrishna

text: The dialogue on psychoanalysis and Ramakrishna began in 1927 when Sigmund Freud's friend Romain Rolland wrote to him that he should consider spiritual experiences, or "the oceanic feeling," in his psychological works. Romain Rolland described the trances and mystical states experienced by Ramakrishna and other mystics as an "'oceanic' sentiment", one which Rolland had also experienced. Rolland believed that the universal human religious emotion resembled this "oceanic sense." In his 1929 book "La vie de Ramakrishna", Rolland distinguished between the feelings of unity and eternity which Ramakrishna experienced in his mystical states and Ramakrishna's interpretation of those feelings as the goddess Kali.


title: Ramakrishna

text: In his 1991 book "The Analyst and the Mystic", Indian psychoanalyst Sudhir Kakar saw in Ramakrishna's visions a spontaneous capacity for creative experiencing. Kakar also argued that culturally relative concepts of eroticism and gender have contributed to the Western difficulty in comprehending Ramakrishna. Kakar saw Ramakrishna's seemingly bizarre acts as part of a "bhakti" path to God.


title: Ramakrishna

text: In 1995, Jeffrey J. Kripal in his controversial "", an interdisciplinary study of Ramakrishna's life "using a range of theoretical models," most notably psycho-analysis, argued that Ramakrishna's mystical experiences could be seen as symptoms of repressed homoeroticism, "legitimat[ing] Ramakrishna's religious visions by situating psychoanalytic discourse in a wider Tantric worldview. Jeffrey J. Kripal argued that Ramakrishna rejected Advaita Vedanta in favour of Shakti Tantra.


title: Ramakrishna

text: Kripal also argued in "Kali's Child" that the Ramakrishna Movement had manipulated Ramakrishna's biographical documents, that the Movement had published them in incomplete and bowdlerised editions (claiming, among other things, hiding Ramakrishna's homoerotic tendencies), and that the Movement had suppressed Ram Chandra Datta's "Srisriramakrsna Paramahamsadever Jivanavrttanta".


title: Ramakrishna

text: These views were disputed by several authors, scholars, and psychoanalysts, including Alan Roland, Kelly Aan Raab, Somnath Bhattacharyya, J.S. Hawley, and Swami Atmajnanananda, who wrote that "Jivanavrttanta" had been reprinted nine times in Bengali as of 1995.


title: Ramakrishna

text: Jeffrey Kripal translates the phrase "kamini-kanchana" as "lover and gold". The literal translation is "Women and Gold". In Ramakrishna's view, lust and greed, are obstacles to God-realization. Kripal associates his translation of the phrase with Ramakrishna's alleged disgust for women as lovers. Swami Tyagananda considered this to be a "linguistic misconstruction." Ramakrishna also cautioned his women disciples against "purusa-kanchana" ("man and gold") and Tyagananda writes that Ramakrishna used "Kamini-Kanchana" as "cautionary words" instructing his disciples to conquer the "lust "inside" the mind."


title: Ramakrishna

text: The application of psychoanalysis has further been disputed by Tyagananda and Vrajaprana as being unreliable in understanding Tantra and interpreting cross-cultural contexts in "" (2010).


title: Surface tension

text: Surface tension is the tendency of liquid surfaces at rest to shrink into the minimum surface area possible. Surface tension is what allows objects with a higher density than water such as razor blades and insects (e.g. water striders) to float on a water surface without becoming even partly submerged.


title: Surface tension

text: At liquid–air interfaces, surface tension results from the greater attraction of liquid molecules to each other (due to cohesion) than to the molecules in the air (due to adhesion).


title: Surface tension

text: There are two primary mechanisms in play. One is an inward force on the surface molecules causing the liquid to contract. Second is a tangential force parallel to the surface of the liquid. This "tangential" force is generally referred to as the surface tension. The net effect is the liquid behaves as if its surface were covered with a stretched elastic membrane. But this analogy must not be taken too far as the tension in an elastic membrane is dependent on the amount of deformation of the membrane while surface tension is an inherent property of the liquid"–"air or liquid"–"vapour interface.


title: Surface tension

text: Because of the relatively high attraction of water molecules to each other through a web of hydrogen bonds, water has a higher surface tension (72.8 millinewtons (mN) per meter at 20 °C) than most other liquids. Surface tension is an important factor in the phenomenon of capillarity.


title: Surface tension

text: Surface tension has the dimension of force per unit length, or of energy per unit area. The two are equivalent, but when referring to energy per unit of area, it is common to use the term surface energy, which is a more general term in the sense that it applies also to solids.


title: Surface tension

text: Due to the cohesive forces, a molecule located away from the surface is pulled equally in every direction by neighbouring liquid molecules, resulting in a net force of zero. The molecules at the surface do not have the "same" molecules on all sides of them and therefore are pulled inward. This creates some internal pressure and forces liquid surfaces to contract to the minimum area.


title: Surface tension

text: There is also a tension parallel to the surface at the liquid-air interface which will resist an external force, due to the cohesive nature of water molecules.


title: Surface tension

text: The forces of attraction acting between molecules of the same type are called cohesive forces, while those acting between molecules of different types are called adhesive forces. The balance between the cohesion of the liquid and its adhesion to the material of the container determines the degree of wetting, the contact angle and the shape of meniscus. When cohesion dominates (specifically, adhesion energy is less than half of cohesion energy) the wetting is low and the meniscus is convex at a vertical wall (as for mercury in a glass container). On the other hand, when adhesion dominates (adhesion energy more than half of cohesion energy) the wetting is high and the similar meniscus is concave (as in water in a glass).


title: Surface tension

text: Surface tension is responsible for the shape of liquid droplets. Although easily deformed, droplets of water tend to be pulled into a spherical shape by the imbalance in cohesive forces of the surface layer. In the absence of other forces, drops of virtually all liquids would be approximately spherical. The spherical shape minimizes the necessary "wall tension" of the surface layer according to Laplace's law.


title: Surface tension

text: Another way to view surface tension is in terms of energy. A molecule in contact with a neighbor is in a lower state of energy than if it were alone. The interior molecules have as many neighbors as they can possibly have, but the boundary molecules are missing neighbors (compared to interior molecules) and therefore have a higher energy. For the liquid to minimize its energy state, the number of higher energy boundary molecules must be minimized. The minimized number of boundary molecules results in a minimal surface area.


title: Surface tension

text: As a result of surface area minimization, a surface will assume the smoothest shape it can (mathematical proof that "smooth" shapes minimize surface area relies on use of the Euler–Lagrange equation). Since any curvature in the surface shape results in greater area, a higher energy will also result.


title: Surface tension

text: Surface tension, represented by the symbol "γ" (alternatively "σ" or "T"), is measured in force per unit length. Its SI unit is newton per meter but the cgs unit of dyne per centimeter is also used. For example,


title: Surface tension

text: Surface tension of a liquid is the force per unit length. In the illustration on the right, the rectangular frame, composed of three unmovable sides (black) that form a "U" shape, and a fourth movable side (blue) that can slide to the right. Surface tension will pull the blue bar to the left; the force required to hold the movable side is proportional to the length of the immobile side. Thus the ratio depends only on the intrinsic properties of the liquid (composition, temperature, etc.), not on its geometry. For example, if the frame had a more complicated shape, the ratio , with the length of the movable side and the force required to stop it from sliding, is found to be the same for all shapes. We therefore define the surface tension as


title: Surface tension

text: The reason for the is that the film has two sides (two surfaces), each of which contributes equally to the force; so the force contributed by a single side is .


title: Surface tension

text: Surface tension of a liquid is the ratio of the change in the energy of the liquid to the change in the surface area of the liquid (that led to the change in energy). This can be easily related to the previous definition in terms of force: if is the force required to stop the side from "starting" to slide, then this is also the force that would keep the side in the state of "sliding at a constant speed" (by Newton's Second Law). But if the side is moving to the right (in the direction the force is applied), then the surface area of the stretched liquid is increasing while the applied force is doing work on the liquid. This means that increasing the surface area increases the energy of the film. The work done by the force in moving the side by distance is ; at the same time the total area of the film increases by (the factor of 2 is here because the liquid has two sides, two surfaces). Thus, multiplying both the numerator and the denominator of by , we get


title: Surface tension

text: This work is, by the usual arguments, interpreted as being stored as potential energy. Consequently, surface tension can be also measured in SI system as joules per square meter and in the cgs system as ergs per cm. Since mechanical systems try to find a state of minimum potential energy, a free droplet of liquid naturally assumes a spherical shape, which has the minimum surface area for a given volume.


title: Surface tension

text: The equivalence of measurement of energy per unit area to force per unit length can be proven by dimensional analysis.


title: Surface tension

text: Surface tension is visible in other common phenomena, especially when surfactants are used to decrease it:


title: Surface tension

text: If no force acts normal to a tensioned surface, the surface must remain flat. But if the pressure on one side of the surface differs from pressure on the other side, the pressure difference times surface area results in a normal force. In order for the surface tension forces to cancel the force due to pressure, the surface must be curved. The diagram shows how surface curvature of a tiny patch of surface leads to a net component of surface tension forces acting normal to the center of the patch. When all the forces are balanced, the resulting equation is known as the Young–Laplace equation:


title: Surface tension

text: The quantity in parentheses on the right hand side is in fact (twice) the mean curvature of the surface (depending on normalisation).


title: Surface tension

text: Solutions to this equation determine the shape of water drops, puddles, menisci, soap bubbles, and all other shapes determined by surface tension (such as the shape of the impressions that a water strider's feet make on the surface of a pond).


title: Surface tension

text: The table below shows how the internal pressure of a water droplet increases with decreasing radius. For not very small drops the effect is subtle, but the pressure difference becomes enormous when the drop sizes approach the molecular size. (In the limit of a single molecule the concept becomes meaningless.)


title: Surface tension

text: When an object is placed on a liquid, its weight depresses the surface, and if surface tension and downward force become equal then it is balanced by the surface tension forces on either side , which are each parallel to the water's surface at the points where it contacts the object. Notice that small movement in the body may cause the object to sink. As the angle of contact decreases, surface tension decreases. The horizontal components of the two arrows point in opposite directions, so they cancel each other, but the vertical components point in the same direction and therefore add up to balance . The object's surface must not be wettable for this to happen, and its weight must be low enough for the surface tension to support it. If denotes the mass of the needle and acceleration due to gravity, we have


title: Surface tension

text: To find the shape of the minimal surface bounded by some arbitrary shaped frame using strictly mathematical means can be a daunting task. Yet by fashioning the frame out of wire and dipping it in soap-solution, a locally minimal surface will appear in the resulting soap-film within seconds.


title: Surface tension

text: The reason for this is that the pressure difference across a fluid interface is proportional to the mean curvature, as seen in the Young–Laplace equation. For an open soap film, the pressure difference is zero, hence the mean curvature is zero, and minimal surfaces have the property of zero mean curvature.


title: Surface tension

text: The surface of any liquid is an interface between that liquid and some other medium. The top surface of a pond, for example, is an interface between the pond water and the air. Surface tension, then, is not a property of the liquid alone, but a property of the liquid's interface with another medium. If a liquid is in a container, then besides the liquid/air interface at its top surface, there is also an interface between the liquid and the walls of the container. The surface tension between the liquid and air is usually different (greater) than its surface tension with the walls of a container. And where the two surfaces meet, their geometry must be such that all forces balance.


title: Surface tension

text: Where the two surfaces meet, they form a contact angle, , which is the angle the tangent to the surface makes with the solid surface. Note that the angle is measured "through the liquid", as shown in the diagrams above. The diagram to the right shows two examples. Tension forces are shown for the liquid–air interface, the liquid–solid interface, and the solid–air interface. The example on the left is where the difference between the liquid–solid and solid–air surface tension, , is less than the liquid–air surface tension, , but is nevertheless positive, that is


title: Surface tension

text: In the diagram, both the vertical and horizontal forces must cancel exactly at the contact point, known as equilibrium. The horizontal component of is canceled by the adhesive force, .


title: Surface tension

text: The more telling balance of forces, though, is in the vertical direction. The vertical component of must exactly cancel the difference of the forces along the solid surface, .


title: Surface tension

text: This means that although the difference between the liquid–solid and solid–air surface tension, , is difficult to measure directly, it can be inferred from the liquid–air surface tension, , and the equilibrium contact angle, , which is a function of the easily measurable advancing and receding contact angles (see main article contact angle).


title: Surface tension

text: This same relationship exists in the diagram on the right. But in this case we see that because the contact angle is less than 90°, the liquid–solid/solid–air surface tension difference must be negative:


title: Surface tension

text: Observe that in the special case of a water–silver interface where the contact angle is equal to 90°, the liquid–solid/solid–air surface tension difference is exactly zero.


title: Surface tension

text: Another special case is where the contact angle is exactly 180°. Water with specially prepared Teflon approaches this. Contact angle of 180° occurs when the liquid–solid surface tension is exactly equal to the liquid–air surface tension.


title: Surface tension

text: An old style mercury barometer consists of a vertical glass tube about 1 cm in diameter partially filled with mercury, and with a vacuum (called Torricelli's vacuum) in the unfilled volume (see diagram to the right). Notice that the mercury level at the center of the tube is higher than at the edges, making the upper surface of the mercury dome-shaped. The center of mass of the entire column of mercury would be slightly lower if the top surface of the mercury were flat over the entire cross-section of the tube. But the dome-shaped top gives slightly less surface area to the entire mass of mercury. Again the two effects combine to minimize the total potential energy. Such a surface shape is known as a convex meniscus.


title: Surface tension

text: We consider the surface area of the entire mass of mercury, including the part of the surface that is in contact with the glass, because mercury does not adhere to glass at all. So the surface tension of the mercury acts over its entire surface area, including where it is in contact with the glass. If instead of glass, the tube was made out of copper, the situation would be very different. Mercury aggressively adheres to copper. So in a copper tube, the level of mercury at the center of the tube will be lower than at the edges (that is, it would be a concave meniscus). In a situation where the liquid adheres to the walls of its container, we consider the part of the fluid's surface area that is in contact with the container to have "negative" surface tension. The fluid then works to maximize the contact surface area. So in this case increasing the area in contact with the container decreases rather than increases the potential energy. That decrease is enough to compensate for the increased potential energy associated with lifting the fluid near the walls of the container.


title: Surface tension

text: If a tube is sufficiently narrow and the liquid adhesion to its walls is sufficiently strong, surface tension can draw liquid up the tube in a phenomenon known as capillary action. The height to which the column is lifted is given by Jurin's law:


title: Surface tension

text: Pouring mercury onto a horizontal flat sheet of glass results in a puddle that has a perceptible thickness. The puddle will spread out only to the point where it is a little under half a centimetre thick, and no thinner. Again this is due to the action of mercury's strong surface tension. The liquid mass flattens out because that brings as much of the mercury to as low a level as possible, but the surface tension, at the same time, is acting to reduce the total surface area. The result of the compromise is a puddle of a nearly fixed thickness.


title: Surface tension

text: The same surface tension demonstration can be done with water, lime water or even saline, but only on a surface made of a substance to which water does not adhere. Wax is such a substance. Water poured onto a smooth, flat, horizontal wax surface, say a waxed sheet of glass, will behave similarly to the mercury poured onto glass.


title: Surface tension

text: In reality, the thicknesses of the puddles will be slightly less than what is predicted by the above formula because very few surfaces have a contact angle of 180° with any liquid. When the contact angle is less than 180°, the thickness is given by:


title: Surface tension

text: For mercury on glass, = 487 dyn/cm, = 13.5 g/cm and = 140°, which gives = 0.36 cm. For water on paraffin at 25 °C, = 72 dyn/cm, = 1.0 g/cm, and = 107° which gives = 0.44 cm.


title: Surface tension

text: The formula also predicts that when the contact angle is 0°, the liquid will spread out into a micro-thin layer over the surface. Such a surface is said to be fully wettable by the liquid.


title: Surface tension

text: In day-to-day life all of us observe that a stream of water emerging from a faucet will break up into droplets, no matter how smoothly the stream is emitted from the faucet. This is due to a phenomenon called the Plateau–Rayleigh instability, which is entirely a consequence of the effects of surface tension.


title: Surface tension

text: The explanation of this instability begins with the existence of tiny perturbations in the stream. These are always present, no matter how smooth the stream is. If the perturbations are resolved into sinusoidal components, we find that some components grow with time while others decay with time. Among those that grow with time, some grow at faster rates than others. Whether a component decays or grows, and how fast it grows is entirely a function of its wave number (a measure of how many peaks and troughs per centimeter) and the radii of the original cylindrical stream.


title: Surface tension

text: on the idea of surfaces of discontinuity. Gibbs considered the case of a sharp mathematical surface being placed somewhere within the microscopically fuzzy physical interface that exists between two homogeneous substances. Realizing that the exact choice of the surface's location was somewhat arbitrary, he left it flexible. Since the interface exists in thermal and chemical equilibrium with the substances around it (having temperature and chemical potentials ), Gibbs considered the case where the surface may have excess energy, excess entropy, and excess particles, finding the natural free energy function in this case to be formula_15, a quantity later named as the grand potential and given the symbol formula_16.


title: Surface tension

text: Considering a given subvolume formula_17 containing a surface of discontinuity, the volume is divided by the mathematical surface into two parts A and B, with volumes formula_18 and formula_19, with formula_20 exactly. Now, if the two parts A and B were homogeneous fluids (with pressures formula_21, formula_22) and remained perfectly homogeneous right up to the mathematical boundary, without any surface effects, the total grand potential of this volume would be simply formula_23. The surface effects of interest are a modification to this, and they can be all collected into a surface free energy term formula_24 so the total grand potential of the volume becomes:


title: Surface tension

text: For sufficiently macroscopic and gently curved surfaces, the surface free energy must simply be proportional to the surface area:


title: Surface tension

text: As stated above, this implies the mechanical work needed to increase a surface area "A" is , assuming the volumes on each side do not change. Thermodynamics requires that for systems held at constant chemical potential and temperature, all spontaneous changes of state are accompanied by a decrease in this free energy formula_16, that is, an increase in total entropy taking into account the possible movement of energy and particles from the surface into the surrounding fluids. From this it is easy to understand why decreasing the surface area of a mass of liquid is always spontaneous, provided it is not coupled to any other energy changes. It follows that in order to increase surface area, a certain amount of energy must be added.


title: Surface tension

text: Gibbs and other scientists have wrestled with the arbitrariness in the exact microscopic placement of the surface. For microscopic surfaces with very tight curvatures, it is not correct to assume the surface tension is independent of size, and topics like the Tolman length come into play. For a macroscopic sized surface (and planar surfaces), the surface placement does not have a significant effect on however it does have a very strong effect on the values of the surface entropy, surface excess mass densities, and surface internal energy, which are the partial derivatives of the surface tension function formula_30.


title: Surface tension

text: Gibbs emphasized that for solids, the surface free energy may be completely different from surface stress (what he called surface tension): the surface free energy is the work required to "form" the surface, while surface stress is the work required to "stretch" the surface. In the case of a two-fluid interface, there is no distinction between forming and stretching because the fluids and the surface completely replenish their nature when the surface is stretched. For a solid, stretching the surface, even elastically, results in a fundamentally changed surface. Further, the surface stress on a solid is a directional quantity (a stress tensor) while surface energy is scalar.


title: Surface tension

text: Fifteen years after Gibbs, J.D. van der Waals developed the theory of capillarity effects based on the hypothesis of a continuous variation of density. He added to the energy density the term formula_31 where "c" is the capillarity coefficient and "ρ" is the density. For the multiphase "equilibria", the results of the van der Waals approach practically coincide with the Gibbs formulae, but for modelling of the "dynamics" of phase transitions the van der Waals approach is much more convenient. The van der Waals capillarity energy is now widely used in the phase field models of multiphase flows. Such terms are also discovered in the dynamics of non-equilibrium gases.


title: Surface tension

text: The pressure inside an ideal spherical bubble can be derived from thermodynamic free energy considerations. The above free energy can be written as:


title: Surface tension

text: where formula_33 is the pressure difference between the inside (A) and outside (B) of the bubble, and formula_18 is the bubble volume. In equilibrium, , and so,


title: Surface tension

text: Surface tension is dependent on temperature. For that reason, when a value is given for the surface tension of an interface, temperature must be explicitly stated. The general trend is that surface tension decreases with the increase of temperature, reaching a value of 0 at the critical temperature. For further details see Eötvös rule. There are only empirical equations to relate surface tension and temperature:


title: Surface tension

text: Both Guggenheim–Katayama and Eötvös take into account the fact that surface tension reaches 0 at the critical temperature, whereas Ramay and Shields fails to match reality at this endpoint.


title: Surface tension

text: Solutes can have different effects on surface tension depending on the nature of the surface and the solute:


title: Surface tension

text: What complicates the effect is that a solute can exist in a different concentration at the surface of a solvent than in its bulk. This difference varies from one solute–solvent combination to another.


title: Surface tension

text: Certain assumptions are taken in its deduction, therefore Gibbs isotherm can only be applied to ideal (very dilute) solutions with two components.


title: Surface tension

text: The Clausius–Clapeyron relation leads to another equation also attributed to Kelvin, as the Kelvin equation. It explains why, because of surface tension, the vapor pressure for small droplets of liquid in suspension is greater than standard vapor pressure of that same liquid when the interface is flat. That is to say that when a liquid is forming small droplets, the equilibrium concentration of its vapor in its surroundings is greater. This arises because the pressure inside the droplet is greater than outside.


title: Surface tension

text: The effect explains supersaturation of vapors. In the absence of nucleation sites, tiny droplets must form before they can evolve into larger droplets. This requires a vapor pressure many times the vapor pressure at the phase transition point.


title: Surface tension

text: The effect can be viewed in terms of the average number of molecular neighbors of surface molecules (see diagram).


title: Surface tension

text: The effect becomes clear for very small drop sizes, as a drop of 1 nm radius has about 100 molecules inside, which is a quantity small enough to require a quantum mechanics analysis.


title: Surface tension

text: Because surface tension manifests itself in various effects, it offers a number of paths to its measurement. Which method is optimal depends upon the nature of the liquid being measured, the conditions under which its tension is to be measured, and the stability of its surface when it is deformed. An instrument that measures surface tension is called tensiometer.


title: Surface tension

text: where both and the critical temperature = 647.096 K are expressed in kelvins. The region of validity the entire vapor–liquid saturation curve, from the triple point (0.01 °C) to the critical point. It also provides reasonable results when extrapolated to metastable (supercooled) conditions, down to at least −25 °C. This formulation was originally adopted by IAPWS in 1976 and was adjusted in 1994 to conform to the International Temperature Scale of 1990.


title: Surface tension

text: The uncertainty of this formulation is given over the full range of temperature by IAPWS. For temperatures below 100 °C, the uncertainty is ±0.5%.


title: Surface tension

text: Nayar et al. published reference data for the surface tension of seawater over the salinity range of and a temperature range of at atmospheric pressure. The range of temperature and salinity encompasses both the oceanographic range and the range of conditions encountered in thermal desalination technologies. The uncertainty of the measurements varied from 0.18 to 0.37 mN/m with the average uncertainty being 0.22 mN/m.


title: Surface tension

text: where is the surface tension of seawater in mN/m, is the surface tension of water in mN/m, is the reference salinity in g/kg, and is temperature in degrees Celsius. The average absolute percentage deviation between measurements and the correlation was 0.19% while the maximum deviation is 0.60%.


title: Surface tension

text: The International Association for the Properties of Water and Steam (IAPWS) has adopted this correlation as an international standard guideline.


title: Orthopedic surgery

text: Orthopedic surgery or orthopedics (alternatively spelt orthopaedics), is the branch of surgery concerned with conditions involving the musculoskeletal system. Orthopedic surgeons use both surgical and nonsurgical means to treat musculoskeletal trauma, spine diseases, sports injuries, degenerative diseases, infections, tumors, and congenital disorders.


title: Orthopedic surgery

text: Nicholas Andry coined the word in French as "", derived from the Ancient Greek words ὀρθός "orthos" ("correct", "straight") and παιδίον "paidion" ("child"), and published "Orthopedie" (translated as "Orthopædia: Or the Art of Correcting and Preventing Deformities in Children") in 1741. The word was assimilated into English as "orthopædics"; the ligature "æ" was common in that era for "ae" in Greek- and Latin-based words. As the name implies, the discipline was initially developed with attention to children, but the correction of spinal and bone deformities in all stages of life eventually became the cornerstone of orthopedic practice.


title: Orthopedic surgery

text: As with many words derived with the "æ" ligature, simplification to either "ae" or just "e" is common, especially in North America. In the US, the majority of college, university, and residency programmes, and even the American Academy of Orthopaedic Surgeons, still use the spelling with the digraph ae, though hospitals usually use the shortened form. Elsewhere, usage is not uniform; in Canada, both spellings are acceptable; "orthopaedics" is the normal spelling in the UK in line with other fields which retain "ae".


title: Orthopedic surgery

text: Many developments in orthopedic surgery have resulted from experiences during wartime. On the battlefields of the Middle Ages, the injured were treated with bandages soaked in horses' blood, which dried to form a stiff, if unsanitary, splint.


title: Orthopedic surgery

text: Originally, the term orthopedics meant the correcting of musculoskeletal deformities in children. Nicolas Andry, a professor of medicine at the University of Paris, coined the term in the first textbook written on the subject in 1741. He advocated the use of exercise, manipulation, and splinting to treat deformities in children. His book was directed towards parents, and while some topics would be familiar to orthopedists today, it also included 'excessive sweating of the palms' and freckles.


title: Orthopedic surgery

text: Jean-André Venel established the first orthopedic institute in 1780, which was the first hospital dedicated to the treatment of children's skeletal deformities. He developed the club-foot shoe for children born with foot deformities and various methods to treat curvature of the spine.


title: Orthopedic surgery

text: Advances made in surgical technique during the 18th century, such as John Hunter's research on tendon healing and Percival Pott's work on spinal deformity steadily increased the range of new methods available for effective treatment. Robert Chessher, a pioneering British orthopedist, invented the double-inclined plane, used to treat lower-body bone fractures, in 1790. Antonius Mathijsen, a Dutch military surgeon, invented the plaster of Paris cast in 1851. Until the 1890s, though, orthopedics was still a study limited to the correction of deformity in children. One of the first surgical procedures developed was percutaneous tenotomy. This involved cutting a tendon, originally the Achilles tendon, to help treat deformities alongside bracing and exercises. In the late 1800s and first decades of the 1900s, significant controversy arose about whether orthopedics should include surgical procedures at all.


title: Orthopedic surgery

text: Examples of people who aided the development of modern orthopedic surgery were Hugh Owen Thomas, a surgeon from Wales, and his nephew, Robert Jones. Thomas became interested in orthopedics and bone-setting at a young age, and after establishing his own practice, went on to expand the field into the general treatment of fracture and other musculoskeletal problems. He advocated enforced rest as the best remedy for fractures and tuberculosis, and created the so-called "Thomas splint" to stabilize a fractured femur and prevent infection. He is also responsible for numerous other medical innovations that all carry his name: Thomas's collar to treat tuberculosis of the cervical spine, Thomas's manoeuvre, an orthopedic investigation for fracture of the hip joint, the Thomas test, a method of detecting hip deformity by having the patient lying flat in bed, and Thomas's wrench for reducing fractures, as well as an osteoclast to break and reset bones.


title: Orthopedic surgery

text: Thomas's work was not fully appreciated in his own lifetime. Only during the First World War did his techniques come to be used for injured soldiers on the battlefield. His nephew, Sir Robert Jones, had already made great advances in orthopedics in his position as surgeon-superintendent for the construction of the Manchester Ship Canal in 1888. He was responsible for the injured among the 20,000 workers, and he organized the first comprehensive accident service in the world, dividing the 36-mile site into three sections, and establishing a hospital and a string of first-aid posts in each section. He had the medical personnel trained in fracture management. He personally managed 3,000 cases and performed 300 operations in his own hospital. This position enabled him to learn new techniques and improve the standard of fracture management. Physicians from around the world came to Jones' clinic to learn his techniques. Along with Alfred Tubby, Jones founded the British Orthopedic Society in 1894.


title: Orthopedic surgery

text: During the First World War, Jones served as a Territorial Army surgeon. He observed that treatment of fractures both, at the front and in hospitals at home, was inadequate, and his efforts led to the introduction of military orthopedic hospitals. He was appointed Inspector of Military Orthopedics, with responsibility for 30,000 beds. The hospital in Ducane Road, Hammersmith, became the model for both British and American military orthopedic hospitals. His advocacy of the use of Thomas splint for the initial treatment of femoral fractures reduced mortality of compound fractures of the femur from 87% to less than 8% in the period from 1916 to 1918.


title: Orthopedic surgery

text: The use of intramedullary rods to treat fractures of the femur and tibia was pioneered by Gerhard Küntscher of Germany. This made a noticeable difference to the speed of recovery of injured German soldiers during World War II and led to more widespread adoption of intramedullary fixation of fractures in the rest of the world. Traction was the standard method of treating thigh bone fractures until the late 1970s, though, when the Harborview Medical Center group in Seattle popularized intramedullary fixation without opening up the fracture.


title: Orthopedic surgery

text: The modern total hip replacement was pioneered by Sir John Charnley, expert in tribology at Wrightington Hospital, in England in the 1960s. He found that joint surfaces could be replaced by implants cemented to the bone. His design consisted of a stainless steel, one-piece femoral stem and head, and a polyethylene acetabular component, both of which were fixed to the bone using PMMA (acrylic) bone cement. For over two decades, the Charnley low-friction arthroplasty and its derivative designs were the most-used systems in the world. This formed the basis for all modern hip implants.


title: Orthopedic surgery

text: The Exeter hip replacement system (with a slightly different stem geometry) was developed at the same time. Since Charnley, improvements have been continuous in the design and technique of joint replacement (arthroplasty) with many contributors, including W. H. Harris, the son of R. I. Harris, whose team at Harvard pioneered uncemented arthroplasty techniques with the bone bonding directly to the implant.


title: Orthopedic surgery

text: Knee replacements, using similar technology, were started by McIntosh in rheumatoid arthritis patients and later by Gunston and Marmor for osteoarthritis in the 1970s, developed by Dr. John Insall in New York using a fixed bearing system, and by Dr. Frederick Buechel and Dr. Michael Pappas using a mobile bearing system.


title: Orthopedic surgery

text: External fixation of fractures was refined by American surgeons during the Vietnam War, but a major contribution was made by Gavril Abramovich Ilizarov in the USSR. He was sent, without much orthopedic training, to look after injured Russian soldiers in Siberia in the 1950s. With no equipment, he was confronted with crippling conditions of unhealed, infected, and misaligned fractures. With the help of the local bicycle shop, he devised ring external fixators tensioned like the spokes of a bicycle. With this equipment, he achieved healing, realignment, and lengthening to a degree unheard of elsewhere. His Ilizarov apparatus is still used today as one of the distraction osteogenesis methods.


title: Orthopedic surgery

text: Modern orthopedic surgery and musculoskeletal research have sought to make surgery less invasive and to make implanted components better and more durable. On the other hand, since the emergence of the opioid epidemic, Orthopedic Surgeons have been identified as one of the highest prescribers of opioid medications. The future of Orthopedic Surgery will likely focus on finding ways for the profession to decrease prescription of opioids while still providing adequate pain control for patients.


title: Orthopedic surgery

text: In the United States, orthopedic surgeons have typically completed four years of undergraduate education and four years of medical school and earned either a Doctor of Medicine (MD) or Doctor of Osteopathic Medicine (DO) degree. Subsequently, these medical school graduates undergo residency training in orthopedic surgery. The five-year residency is a categorical orthopedic surgery training.


title: Orthopedic surgery

text: Selection for residency training in orthopedic surgery is very competitive. Roughly 700 physicians complete orthopedic residency training per year in the United States. About 10% of current orthopedic surgery residents are women; about 20% are members of minority groups. Around 20,400 actively practicing orthopedic surgeons and residents are in the United States. According to the latest Occupational Outlook Handbook (2011–2012) published by the United States Department of Labor, 3 to 4% of all practicing physicians are orthopedic surgeons.


title: Orthopedic surgery

text: Many orthopedic surgeons elect to do further training, or fellowships, after completing their residency training. Fellowship training in an orthopedic sub-specialty is typically one year in duration (sometimes two) and sometimes has a research component involved with the clinical and operative training. Examples of orthopedic subspecialty training in the United States are:


title: Orthopedic surgery

text: These specialized areas of medicine are not exclusive to orthopedic surgery. For example, hand surgery is practiced by some plastic surgeons, and spine surgery is practiced by most neurosurgeons. Additionally, some aspects of foot and ankle surgery are also practiced by board-certified doctors of podiatric medicine (DPM) in the United States. Some family practice physicians practice sports medicine, but their scope of practice is nonoperative.


title: Orthopedic surgery

text: After completion of specialty residency/registrar training, an orthopedic surgeon is then eligible for board certification by the American Board of Medical Specialties or the American Osteopathic Association Bureau of Osteopathic Specialists. Certification by the American Board of Orthopedic Surgery or the American Osteopathic Board of Orthopedic Surgery means that the orthopedic surgeon has met the specified educational, evaluation, and examination requirements of the board. The process requires successful completion of a standardized written examination followed by an oral examination focused on the surgeon's clinical and surgical performance over a 6-month period. In Canada, the certifying organization is the Royal College of Physicians and Surgeons of Canada; in Australia and New Zealand, it is the Royal Australasian College of Surgeons.


title: Orthopedic surgery

text: In the United States, specialists in hand surgery and orthopedic sports medicine may obtain a certificate of added qualifications in addition to their board primary certification by successfully completing a separate standardized examination. No additional certification process exists for the other subspecialties.


title: Orthopedic surgery

text: According to applications for board certification from 1999 to 2003, the top 25 most common procedures (in order) performed by orthopedic surgeons are:


title: Orthopedic surgery

text: A typical schedule for a practicing orthopedic surgeon involves 50–55 hours of work per week divided among clinic, surgery, various administrative duties, and possibly teaching and/or research if in an academic setting. According to the American Association of Medical Colleges in 2021, the average work week of an orthopedic surgeon was 57 hours. This is a very low estimation however, as research derived from a 2013 survey of orthopedic surgeons who self identified as "highly successful" due to their prominent positions in the field indicated average work weeks of 70 hours or more.


title: Orthopedic surgery

text: The use of arthroscopic techniques has been particularly important for injured patients. Arthroscopy was pioneered in the early 1950s by Dr. Masaki Watanabe of Japan to perform minimally invasive cartilage surgery and reconstructions of torn ligaments. Arthroscopy allows patients to recover from the surgery in a matter of days, rather than the weeks to months required by conventional, "open" surgery; it is a very popular technique. Knee arthroscopy is one of the most common operations performed by orthopedic surgeons today, and is often combined with meniscectomy or chondroplasty. The majority of upper-extremity outpatient orthopedic procedures are now performed arthroscopically.


title: Orthopedic surgery

text: Arthroplasty is an orthopedic surgery where the articular surface of a musculoskeletal joint is replaced, remodeled, or realigned by osteotomy or some other procedure. It is an elective procedure that is done to relieve pain and restore function to the joint after damage by arthritis (rheumasurgery) or some other type of trauma. As well as the standard total knee replacement surgery, the uni-compartmental knee replacement, in which only one weight-bearing surface of an arthritic knee is replaced, is a popular alternative.


title: Orthopedic surgery

text: Joint replacements are available for other joints on a variable basis, most notably the hip, shoulder, elbow, wrist, ankle, spine, and finger joints.


title: Orthopedic surgery

text: In recent years, surface replacement of joints, in particular the hip joint, has become more popular amongst younger and more active patients. This type of operation delays the need for the more traditional and less bone-conserving total hip replacement, but carries significant risks of early failure from fracture and bone death.


title: Orthopedic surgery

text: One of the main problems with joint replacements is wear of the bearing surfaces of components. This can lead to damage to the surrounding bone and contribute to eventual failure of the implant. The use of alternative bearing surfaces has increased in recent years, particularly in younger patients, in an attempt to improve the wear characteristics of joint replacement components. These include ceramics and all-metal implants (as opposed to the original metal-on-plastic). The plastic chosen is usually ultra-high-molecular-weight polyethylene, which can also be altered in ways that may improve wear characteristics.


title: Orthopedic surgery

text: Between 2001 and 2016, the prevalence of musculoskeletal procedures drastically increased in the U.S, from 17.9% to 24.2% of all operating-room (OR) procedures performed during hospital stays.


title: Orthopedic surgery

text: In a study of hospitalizations in the United States in 2012, spine and joint procedures were common among all age groups except infants. Spinal fusion was one of the five most common OR procedures performed in every age group except infants younger than 1 year and adults 85 years and older. Laminectomy was common among adults aged 18–84 years. Knee arthroplasty and hip replacement were in the top five OR procedures for adults aged 45 years and older.


title: Genetic engineering

text: Genetic engineering, also called genetic modification or genetic manipulation, is the modification and manipulation of an organism's genes using technology. It is a set of technologies used to change the genetic makeup of cells, including the transfer of genes within and across species boundaries to produce improved or novel organisms. New DNA is obtained by either isolating and copying the genetic material of interest using recombinant DNA methods or by artificially synthesising the DNA. A construct is usually created and used to insert this DNA into the host organism. The first recombinant DNA molecule was made by Paul Berg in 1972 by combining DNA from the monkey virus SV40 with the lambda virus. As well as inserting genes, the process can be used to remove, or "knock out", genes. The new DNA can be inserted randomly, or targeted to a specific part of the genome.


title: Genetic engineering

text: An organism that is generated through genetic engineering is considered to be genetically modified (GM) and the resulting entity is a genetically modified organism (GMO). The first GMO was a bacterium generated by Herbert Boyer and Stanley Cohen in 1973. Rudolf Jaenisch created the first GM animal when he inserted foreign DNA into a mouse in 1974. The first company to focus on genetic engineering, Genentech, was founded in 1976 and started the production of human proteins. Genetically engineered human insulin was produced in 1978 and insulin-producing bacteria were commercialised in 1982. Genetically modified food has been sold since 1994, with the release of the Flavr Savr tomato. The Flavr Savr was engineered to have a longer shelf life, but most current GM crops are modified to increase resistance to insects and herbicides. GloFish, the first GMO designed as a pet, was sold in the United States in December 2003. In 2016 salmon modified with a growth hormone were sold.


title: Genetic engineering

text: Genetic engineering has been applied in numerous fields including research, medicine, industrial biotechnology and agriculture. In research GMOs are used to study gene function and expression through loss of function, gain of function, tracking and expression experiments. By knocking out genes responsible for certain conditions it is possible to create animal model organisms of human diseases. As well as producing hormones, vaccines and other drugs, genetic engineering has the potential to cure genetic diseases through gene therapy. The same techniques that are used to produce drugs can also have industrial applications such as producing enzymes for laundry detergent, cheeses and other products.


title: Genetic engineering

text: The rise of commercialised genetically modified crops has provided economic benefit to farmers in many different countries, but has also been the source of most of the controversy surrounding the technology. This has been present since its early use; the first field trials were destroyed by anti-GM activists. Although there is a scientific consensus that currently available food derived from GM crops poses no greater risk to human health than conventional food, critics consider GM food safety a leading concern. Gene flow, impact on non-target organisms, control of the food supply and intellectual property rights have also been raised as potential issues. These concerns have led to the development of a regulatory framework, which started in 1975. It has led to an international treaty, the Cartagena Protocol on Biosafety, that was adopted in 2000. Individual countries have developed their own regulatory systems regarding GMOs, with the most marked differences occurring between the US and Europe.


title: Genetic engineering

text: Genetic engineering is a process that alters the genetic structure of an organism by either removing or introducing DNA, or modifying existing genetic material in situ. Unlike traditional animal and plant breeding, which involves doing multiple crosses and then selecting for the organism with the desired phenotype, genetic engineering takes the gene directly from one organism and delivers it to the other. This is much faster, can be used to insert any genes from any organism (even ones from different domains) and prevents other undesirable genes from also being added.


title: Genetic engineering

text: Genetic engineering could potentially fix severe genetic disorders in humans by replacing the defective gene with a functioning one. It is an important tool in research that allows the function of specific genes to be studied. Drugs, vaccines and other products have been harvested from organisms engineered to produce them. Crops have been developed that aid food security by increasing yield, nutritional value and tolerance to environmental stresses.


title: Genetic engineering

text: The DNA can be introduced directly into the host organism or into a cell that is then fused or hybridised with the host. This relies on recombinant nucleic acid techniques to form new combinations of heritable genetic material followed by the incorporation of that material either indirectly through a vector system or directly through micro-injection, macro-injection or micro-encapsulation.


title: Genetic engineering

text: Genetic engineering does not normally include traditional breeding, in vitro fertilisation, induction of polyploidy, mutagenesis and cell fusion techniques that do not use recombinant nucleic acids or a genetically modified organism in the process. However, some broad definitions of genetic engineering include selective breeding. Cloning and stem cell research, although not considered genetic engineering, are closely related and genetic engineering can be used within them. Synthetic biology is an emerging discipline that takes genetic engineering a step further by introducing artificially synthesised material into an organism.


title: Genetic engineering

text: Plants, animals or microorganisms that have been changed through genetic engineering are termed genetically modified organisms or GMOs. If genetic material from another species is added to the host, the resulting organism is called transgenic. If genetic material from the same species or a species that can naturally breed with the host is used the resulting organism is called cisgenic. If genetic engineering is used to remove genetic material from the target organism the resulting organism is termed a knockout organism. In Europe genetic modification is synonymous with genetic engineering while within the United States of America and Canada genetic modification can also be used to refer to more conventional breeding methods.


title: Genetic engineering

text: Humans have altered the genomes of species for thousands of years through selective breeding, or artificial selection as contrasted with natural selection. More recently, mutation breeding has used exposure to chemicals or radiation to produce a high frequency of random mutations, for selective breeding purposes. Genetic engineering as the direct manipulation of DNA by humans outside breeding and mutations has only existed since the 1970s. The term "genetic engineering" was first coined by Jack Williamson in his science fiction novel "Dragon's Island", published in 1951 – one year before DNA's role in heredity was confirmed by Alfred Hershey and Martha Chase, and two years before James Watson and Francis Crick showed that the DNA molecule has a double-helix structure – though the general concept of direct genetic manipulation was explored in rudimentary form in Stanley G. Weinbaum's 1936 science fiction story "Proteus Island".


title: Genetic engineering

text: In 1972, Paul Berg created the first recombinant DNA molecules by combining DNA from the monkey virus SV40 with that of the lambda virus. In 1973 Herbert Boyer and Stanley Cohen created the first transgenic organism by inserting antibiotic resistance genes into the plasmid of an "Escherichia coli" bacterium. A year later Rudolf Jaenisch created a transgenic mouse by introducing foreign DNA into its embryo, making it the world's first transgenic animal These achievements led to concerns in the scientific community about potential risks from genetic engineering, which were first discussed in depth at the Asilomar Conference in 1975. One of the main recommendations from this meeting was that government oversight of recombinant DNA research should be established until the technology was deemed safe.


title: Genetic engineering

text: In 1976 Genentech, the first genetic engineering company, was founded by Herbert Boyer and Robert Swanson and a year later the company produced a human protein (somatostatin) in "E. coli". Genentech announced the production of genetically engineered human insulin in 1978. In 1980, the U.S. Supreme Court in the "Diamond v. Chakrabarty" case ruled that genetically altered life could be patented. The insulin produced by bacteria was approved for release by the Food and Drug Administration (FDA) in 1982.


title: Genetic engineering

text: In 1983, a biotech company, Advanced Genetic Sciences (AGS) applied for U.S. government authorisation to perform field tests with the ice-minus strain of "Pseudomonas syringae" to protect crops from frost, but environmental groups and protestors delayed the field tests for four years with legal challenges. In 1987, the ice-minus strain of "P. syringae" became the first genetically modified organism (GMO) to be released into the environment when a strawberry field and a potato field in California were sprayed with it. Both test fields were attacked by activist groups the night before the tests occurred: "The world's first trial site attracted the world's first field trasher".


title: Genetic engineering

text: The first field trials of genetically engineered plants occurred in France and the US in 1986, tobacco plants were engineered to be resistant to herbicides. The People's Republic of China was the first country to commercialise transgenic plants, introducing a virus-resistant tobacco in 1992. In 1994 Calgene attained approval to commercially release the first genetically modified food, the Flavr Savr, a tomato engineered to have a longer shelf life. In 1994, the European Union approved tobacco engineered to be resistant to the herbicide bromoxynil, making it the first genetically engineered crop commercialised in Europe. In 1995, Bt potato was approved safe by the Environmental Protection Agency, after having been approved by the FDA, making it the first pesticide producing crop to be approved in the US. In 2009 11 transgenic crops were grown commercially in 25 countries, the largest of which by area grown were the US, Brazil, Argentina, India, Canada, China, Paraguay and South Africa.


title: Genetic engineering

text: In 2010, scientists at the J. Craig Venter Institute created the first synthetic genome and inserted it into an empty bacterial cell. The resulting bacterium, named Mycoplasma laboratorium, could replicate and produce proteins. Four years later this was taken a step further when a bacterium was developed that replicated a plasmid containing a unique base pair, creating the first organism engineered to use an expanded genetic alphabet. In 2012, Jennifer Doudna and Emmanuelle Charpentier collaborated to develop the CRISPR/Cas9 system, a technique which can be used to easily and specifically alter the genome of almost any organism.


title: Genetic engineering

text: Creating a GMO is a multi-step process. Genetic engineers must first choose what gene they wish to insert into the organism. This is driven by what the aim is for the resultant organism and is built on earlier research. Genetic screens can be carried out to determine potential genes and further tests then used to identify the best candidates. The development of microarrays, transcriptomics and genome sequencing has made it much easier to find suitable genes. Luck also plays its part; the Roundup Ready gene was discovered after scientists noticed a bacterium thriving in the presence of the herbicide.


title: Genetic engineering

text: The next step is to isolate the candidate gene. The cell containing the gene is opened and the DNA is purified. The gene is separated by using restriction enzymes to cut the DNA into fragments or polymerase chain reaction (PCR) to amplify up the gene segment. These segments can then be extracted through gel electrophoresis. If the chosen gene or the donor organism's genome has been well studied it may already be accessible from a genetic library. If the DNA sequence is known, but no copies of the gene are available, it can also be artificially synthesised. Once isolated the gene is ligated into a plasmid that is then inserted into a bacterium. The plasmid is replicated when the bacteria divide, ensuring unlimited copies of the gene are available. The RK2 plasmid is notable for its ability to replicate in a wide variety of single-celled organisms, which makes it suitable as a genetic engineering tool.


title: Genetic engineering

text: Before the gene is inserted into the target organism it must be combined with other genetic elements. These include a promoter and terminator region, which initiate and end transcription. A selectable marker gene is added, which in most cases confers antibiotic resistance, so researchers can easily determine which cells have been successfully transformed. The gene can also be modified at this stage for better expression or effectiveness. These manipulations are carried out using recombinant DNA techniques, such as restriction digests, ligations and molecular cloning.


title: Genetic engineering

text: There are a number of techniques used to insert genetic material into the host genome. Some bacteria can naturally take up foreign DNA. This ability can be induced in other bacteria via stress (e.g. thermal or electric shock), which increases the cell membrane's permeability to DNA; up-taken DNA can either integrate with the genome or exist as extrachromosomal DNA. DNA is generally inserted into animal cells using microinjection, where it can be injected through the cell's nuclear envelope directly into the nucleus, or through the use of viral vectors.


title: Genetic engineering

text: Plant genomes can be engineered by physical methods or by use of "Agrobacterium" for the delivery of sequences hosted in T-DNA binary vectors. In plants the DNA is often inserted using "Agrobacterium"-mediated transformation, taking advantage of the "Agrobacterium"s T-DNA sequence that allows natural insertion of genetic material into plant cells. Other methods include biolistics, where particles of gold or tungsten are coated with DNA and then shot into young plant cells, and electroporation, which involves using an electric shock to make the cell membrane permeable to plasmid DNA.


title: Genetic engineering

text: As only a single cell is transformed with genetic material, the organism must be regenerated from that single cell. In plants this is accomplished through the use of tissue culture. In animals it is necessary to ensure that the inserted DNA is present in the embryonic stem cells. Bacteria consist of a single cell and reproduce clonally so regeneration is not necessary. Selectable markers are used to easily differentiate transformed from untransformed cells. These markers are usually present in the transgenic organism, although a number of strategies have been developed that can remove the selectable marker from the mature transgenic plant.


title: Genetic engineering

text: Further testing using PCR, Southern hybridization, and DNA sequencing is conducted to confirm that an organism contains the new gene. These tests can also confirm the chromosomal location and copy number of the inserted gene. The presence of the gene does not guarantee it will be expressed at appropriate levels in the target tissue so methods that look for and measure the gene products (RNA and protein) are also used. These include northern hybridisation, quantitative RT-PCR, Western blot, immunofluorescence, ELISA and phenotypic analysis.


title: Genetic engineering

text: The new genetic material can be inserted randomly within the host genome or targeted to a specific location. The technique of gene targeting uses homologous recombination to make desired changes to a specific endogenous gene. This tends to occur at a relatively low frequency in plants and animals and generally requires the use of selectable markers. The frequency of gene targeting can be greatly enhanced through genome editing. Genome editing uses artificially engineered nucleases that create specific double-stranded breaks at desired locations in the genome, and use the cell's endogenous mechanisms to repair the induced break by the natural processes of homologous recombination and nonhomologous end-joining. There are four families of engineered nucleases: meganucleases, zinc finger nucleases, transcription activator-like effector nucleases (TALENs), and the Cas9-guideRNA system (adapted from CRISPR). TALEN and CRISPR are the two most commonly used and each has its own advantages. TALENs have greater target specificity, while CRISPR is easier to design and more efficient. In addition to enhancing gene targeting, engineered nucleases can be used to introduce mutations at endogenous genes that generate a gene knockout.


title: Genetic engineering

text: Genetic engineering has applications in medicine, research, industry and agriculture and can be used on a wide range of plants, animals and microorganisms. Bacteria, the first organisms to be genetically modified, can have plasmid DNA inserted containing new genes that code for medicines or enzymes that process food and other substrates. Plants have been modified for insect protection, herbicide resistance, virus resistance, enhanced nutrition, tolerance to environmental pressures and the production of edible vaccines. Most commercialised GMOs are insect resistant or herbicide tolerant crop plants. Genetically modified animals have been used for research, model animals and the production of agricultural or pharmaceutical products. The genetically modified animals include animals with genes knocked out, increased susceptibility to disease, hormones for extra growth and the ability to express proteins in their milk.


title: Genetic engineering

text: Genetic engineering has many applications to medicine that include the manufacturing of drugs, creation of model animals that mimic human conditions and gene therapy. One of the earliest uses of genetic engineering was to mass-produce human insulin in bacteria. This application has now been applied to human growth hormones, follicle stimulating hormones (for treating infertility), human albumin, monoclonal antibodies, antihemophilic factors, vaccines and many other drugs. Mouse hybridomas, cells fused together to create monoclonal antibodies, have been adapted through genetic engineering to create human monoclonal antibodies. Genetically engineered viruses are being developed that can still confer immunity, but lack the infectious sequences.


title: Genetic engineering

text: Genetic engineering is also used to create animal models of human diseases. Genetically modified mice are the most common genetically engineered animal model. They have been used to study and model cancer (the oncomouse), obesity, heart disease, diabetes, arthritis, substance abuse, anxiety, aging and Parkinson disease. Potential cures can be tested against these mouse models.


title: Genetic engineering

text: Gene therapy is the genetic engineering of humans, generally by replacing defective genes with effective ones. Clinical research using somatic gene therapy has been conducted with several diseases, including X-linked SCID, chronic lymphocytic leukemia (CLL), and Parkinson's disease. In 2012, Alipogene tiparvovec became the first gene therapy treatment to be approved for clinical use. In 2015 a virus was used to insert a healthy gene into the skin cells of a boy suffering from a rare skin disease, epidermolysis bullosa, in order to grow, and then graft healthy skin onto 80 percent of the boy's body which was affected by the illness.


title: Genetic engineering

text: Germline gene therapy would result in any change being inheritable, which has raised concerns within the scientific community. In 2015, CRISPR was used to edit the DNA of non-viable human embryos, leading scientists of major world academies to call for a moratorium on inheritable human genome edits. There are also concerns that the technology could be used not just for treatment, but for enhancement, modification or alteration of a human beings' appearance, adaptability, intelligence, character or behavior. The distinction between cure and enhancement can also be difficult to establish. In November 2018, He Jiankui announced that he had edited the genomes of two human embryos, to attempt to disable the "CCR5" gene, which codes for a receptor that HIV uses to enter cells. The work was widely condemned as unethical, dangerous, and premature. Currently, germline modification is banned in 40 countries. Scientists that do this type of research will often let embryos grow for a few days without allowing it to develop into a baby.


title: Genetic engineering

text: Researchers are altering the genome of pigs to induce the growth of human organs, with the aim of increasing the success of pig to human organ transplantation. Scientists are creating "gene drives", changing the genomes of mosquitoes to make them immune to malaria, and then looking to spread the genetically altered mosquitoes throughout the mosquito population in the hopes of eliminating the disease.


title: Genetic engineering

text: Genetic engineering is an important tool for natural scientists, with the creation of transgenic organisms one of the most important tools for analysis of gene function. Genes and other genetic information from a wide range of organisms can be inserted into bacteria for storage and modification, creating genetically modified bacteria in the process. Bacteria are cheap, easy to grow, clonal, multiply quickly, relatively easy to transform and can be stored at -80 °C almost indefinitely. Once a gene is isolated it can be stored inside the bacteria providing an unlimited supply for research.


title: Genetic engineering

text: Organisms are genetically engineered to discover the functions of certain genes. This could be the effect on the phenotype of the organism, where the gene is expressed or what other genes it interacts with. These experiments generally involve loss of function, gain of function, tracking and expression.


title: Genetic engineering

text: Organisms can have their cells transformed with a gene coding for a useful protein, such as an enzyme, so that they will overexpress the desired protein. Mass quantities of the protein can then be manufactured by growing the transformed organism in bioreactor equipment using industrial fermentation, and then purifying the protein. Some genes do not work well in bacteria, so yeast, insect cells or mammalian cells can also be used. These techniques are used to produce medicines such as insulin, human growth hormone, and vaccines, supplements such as tryptophan, aid in the production of food (chymosin in cheese making) and fuels. Other applications with genetically engineered bacteria could involve making them perform tasks outside their natural cycle, such as making biofuels, cleaning up oil spills, carbon and other toxic waste and detecting arsenic in drinking water. Certain genetically modified microbes can also be used in biomining and bioremediation, due to their ability to extract heavy metals from their environment and incorporate them into compounds that are more easily recoverable.


title: Genetic engineering

text: In materials science, a genetically modified virus has been used in a research laboratory as a scaffold for assembling a more environmentally friendly lithium-ion battery. Bacteria have also been engineered to function as sensors by expressing a fluorescent protein under certain environmental conditions.


title: Genetic engineering

text: One of the best-known and controversial applications of genetic engineering is the creation and use of genetically modified crops or genetically modified livestock to produce genetically modified food. Crops have been developed to increase production, increase tolerance to abiotic stresses, alter the composition of the food, or to produce novel products.


title: Genetic engineering

text: The first crops to be released commercially on a large scale provided protection from insect pests or tolerance to herbicides. Fungal and virus resistant crops have also been developed or are in development. This makes the insect and weed management of crops easier and can indirectly increase crop yield. GM crops that directly improve yield by accelerating growth or making the plant more hardy (by improving salt, cold or drought tolerance) are also under development. In 2016 Salmon have been genetically modified with growth hormones to reach normal adult size much faster.


title: Genetic engineering

text: GMOs have been developed that modify the quality of produce by increasing the nutritional value or providing more industrially useful qualities or quantities. The Amflora potato produces a more industrially useful blend of starches. Soybeans and canola have been genetically modified to produce more healthy oils. The first commercialised GM food was a tomato that had delayed ripening, increasing its shelf life.


title: Genetic engineering

text: Plants and animals have been engineered to produce materials they do not normally make. Pharming uses crops and animals as bioreactors to produce vaccines, drug intermediates, or the drugs themselves; the useful product is purified from the harvest and then used in the standard pharmaceutical production process. Cows and goats have been engineered to express drugs and other proteins in their milk, and in 2009 the FDA approved a drug produced in goat milk.


title: Genetic engineering

text: Genetic engineering has potential applications in conservation and natural area management. Gene transfer through viral vectors has been proposed as a means of controlling invasive species as well as vaccinating threatened fauna from disease. Transgenic trees have been suggested as a way to confer resistance to pathogens in wild populations. With the increasing risks of maladaptation in organisms as a result of climate change and other perturbations, facilitated adaptation through gene tweaking could be one solution to reducing extinction risks. Applications of genetic engineering in conservation are thus far mostly theoretical and have yet to be put into practice.


title: Genetic engineering

text: Genetic engineering is also being used to create microbial art. Some bacteria have been genetically engineered to create black and white photographs. Novelty items such as lavender-colored carnations, blue roses, and glowing fish have also been produced through genetic engineering.


title: Genetic engineering

text: The regulation of genetic engineering concerns the approaches taken by governments to assess and manage the risks associated with the development and release of GMOs. The development of a regulatory framework began in 1975, at Asilomar, California. The Asilomar meeting recommended a set of voluntary guidelines regarding the use of recombinant technology. As the technology improved the US established a committee at the Office of Science and Technology, which assigned regulatory approval of GM food to the USDA, FDA and EPA. The Cartagena Protocol on Biosafety, an international treaty that governs the transfer, handling, and use of GMOs, was adopted on 29 January 2000. One hundred and fifty-seven countries are members of the Protocol, and many use it as a reference point for their own regulations.


title: Genetic engineering

text: The legal and regulatory status of GM foods varies by country, with some nations banning or restricting them, and others permitting them with widely differing degrees of regulation. Some countries allow the import of GM food with authorisation, but either do not allow its cultivation (Russia, Norway, Israel) or have provisions for cultivation even though no GM products are yet produced (Japan, South Korea). Most countries that do not allow GMO cultivation do permit research. Some of the most marked differences occur between the US and Europe. The US policy focuses on the product (not the process), only looks at verifiable scientific risks and uses the concept of substantial equivalence. The European Union by contrast has possibly the most stringent GMO regulations in the world. All GMOs, along with irradiated food, are considered "new food" and subject to extensive, case-by-case, science-based food evaluation by the European Food Safety Authority. The criteria for authorisation fall in four broad categories: "safety", "freedom of choice", "labelling", and "traceability". The level of regulation in other countries that cultivate GMOs lie in between Europe and the United States.


title: Genetic engineering

text: One of the key issues concerning regulators is whether GM products should be labeled. The European Commission says that mandatory labeling and traceability are needed to allow for informed choice, avoid potential false advertising and facilitate the withdrawal of products if adverse effects on health or the environment are discovered. The American Medical Association and the American Association for the Advancement of Science say that absent scientific evidence of harm even voluntary labeling is misleading and will falsely alarm consumers. Labeling of GMO products in the marketplace is required in 64 countries. Labeling can be mandatory up to a threshold GM content level (which varies between countries) or voluntary. In Canada and the US labeling of GM food is voluntary, while in Europe all food (including processed food) or feed which contains greater than 0.9% of approved GMOs must be labelled.


title: Genetic engineering

text: Critics have objected to the use of genetic engineering on several grounds, including ethical, ecological and economic concerns. Many of these concerns involve GM crops and whether food produced from them is safe and what impact growing them will have on the environment. These controversies have led to litigation, international trade disputes, and protests, and to restrictive regulation of commercial products in some countries.


title: Genetic engineering

text: Accusations that scientists are "playing God" and other religious issues have been ascribed to the technology from the beginning. Other ethical issues raised include the patenting of life, the use of intellectual property rights, the level of labeling on products, control of the food supply and the objectivity of the regulatory process. Although doubts have been raised, economically most studies have found growing GM crops to be beneficial to farmers.


title: Genetic engineering

text: Gene flow between GM crops and compatible plants, along with increased use of selective herbicides, can increase the risk of "superweeds" developing. Other environmental concerns involve potential impacts on non-target organisms, including soil microbes, and an increase in secondary and resistant insect pests. Many of the environmental impacts regarding GM crops may take many years to be understood and are also evident in conventional agriculture practices. With the commercialisation of genetically modified fish there are concerns over what the environmental consequences will be if they escape.


title: Genetic engineering

text: There are three main concerns over the safety of genetically modified food: whether they may provoke an allergic reaction; whether the genes could transfer from the food into human cells; and whether the genes not approved for human consumption could outcross to other crops. There is a scientific consensus that currently available food derived from GM crops poses no greater risk to human health than conventional food, but that each GM food needs to be tested on a case-by-case basis before introduction. Nonetheless, members of the public are less likely than scientists to perceive GM foods as safe.


title: Genetic engineering

text: Genetic engineering features in many science fiction stories. Frank Herbert's novel "The White Plague" describes the deliberate use of genetic engineering to create a pathogen which specifically kills women. Another of Herbert's creations, the "Dune" series of novels, uses genetic engineering to create the powerful Tleilaxu. Few films have informed audiences about genetic engineering, with the exception of the 1978 "The Boys from Brazil" and the 1993 "Jurassic Park", both of which make use of a lesson, a demonstration, and a clip of scientific film. Genetic engineering methods are weakly represented in film; Michael Clark, writing for the Wellcome Trust, calls the portrayal of genetic engineering and biotechnology "seriously distorted" in films such as "The 6th Day". In Clark's view, the biotechnology is typically "given fantastic but visually arresting forms" while the science is either relegated to the background or fictionalised to suit a young audience.


title: Genetic engineering

text: In the 2007 video game, "BioShock", genetic engineering plays an important role in the central storyline and universe. The game takes place in the fictional underwater dystopia Rapture, in which its inhabitants possess genetic superhuman abilities after injecting themselves with “plasmids”, a serum which grants such powers. Also in the city of Rapture are “Little Sisters”, little girls who are generically engineered, as well as a side-plot in which a cabaret singer sells her foetus to genetic scientists who implant false memories into the newborn and genetically engineer it to grow into an adult.


title: Giordano Bruno

text: Giordano Bruno (; ; ; born Filippo Bruno, January or February 1548 – 17 February 1600) was an Italian philosopher, mathematician, poet, cosmological theorist, and Hermetic occultist. He is known for his cosmological theories, which conceptually extended the then novel Copernican model. He proposed that the stars were distant suns surrounded by their own planets, and he raised the possibility that these planets might foster life of their own, a cosmological position known as cosmic pluralism. He also insisted that the universe is infinite and could have no "center".


title: Giordano Bruno

text: While Bruno began as a Dominican friar, during his time in Geneva he embraced Calvinism. Bruno was later tried for heresy by the Roman Inquisition on charges of denial of several core Catholic doctrines, including eternal damnation, the Trinity, the divinity of Christ, the virginity of Mary, and transubstantiation. Bruno's pantheism was not taken lightly by the church, nor was his teaching of the transmigration of the soul (reincarnation). The Inquisition found him guilty, and he was burned at the stake in Rome's Campo de' Fiori in 1600. After his death, he gained considerable fame, being particularly celebrated by 19th- and early 20th-century commentators who regarded him as a martyr for science, although most historians agree that his heresy trial was not a response to his cosmological views but rather a response to his religious and afterlife views. However, some historians do contend that the main reason for Bruno's death was indeed his cosmological views. Bruno's case is still considered a landmark in the history of free thought and the emerging sciences.


title: Giordano Bruno

text: In addition to cosmology, Bruno also wrote extensively on the art of memory, a loosely organized group of mnemonic techniques and principles. Historian Frances Yates argues that Bruno was deeply influenced by the presocratic Empedocles, Neoplatonism, Renaissance Hermeticism, and Genesis-like legends surrounding the Hellenistic conception of Hermes Trismegistus. Other studies of Bruno have focused on his qualitative approach to mathematics and his application of the spatial concepts of geometry to language.


title: Giordano Bruno

text: Born Filippo Bruno in Nola (a "comune" in the modern-day province of Naples, in the Southern Italian region of Campania, then part of the Kingdom of Naples) in 1548, he was the son of Giovanni Bruno, a soldier, and Fraulissa Savolino. In his youth he was sent to Naples to be educated. He was tutored privately at the Augustinian monastery there, and attended public lectures at the Studium Generale. At the age of 17, he entered the Dominican Order at the monastery of San Domenico Maggiore in Naples, taking the name Giordano, after Giordano Crispo, his metaphysics tutor. He continued his studies there, completing his novitiate, and ordained a priest in 1572 at age 24. During his time in Naples, he became known for his skill with the art of memory and on one occasion traveled to Rome to demonstrate his mnemonic system before Pope Pius V and Cardinal Rebiba. In his later years, Bruno claimed that the Pope accepted his dedication to him of the lost work "On The Ark of Noah" at this time.