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Hypoxia (environmental) After POC is broken down, this particulate matter can be turned into other dissolved organic carbon, such as carbon dioxide, bicarbonate ions, and carbonate. As much as 30% of phytoplankton can be broken down into dissolved organic carbon. When this particulate organic carbon interacts with 350 nm ultraviolet light, dissolved organic carbon is formed, removing even more oxygen from the environment in the forms of carbon dioxide, bicarbonate ions, and carbonate. Dissolved inorganic carbon is made at a rate of 2.3-6.5 mg/(m^3)day. As phytoplankton breakdown, free phosphorus and nitrogen become available in the environment, which also fosters hypoxic conditions. As the breakdown of these phytoplankton takes place, the more phosphorus turns into phosphates, and nitrogens turn into nitrates. This depletes the oxygen even more so in the environment, further creating hypoxic zones in higher quantities. As more minerals such as phosphorus and nitrogen are displaced into these aquatic systems, the growth of phytoplankton greatly increases, and after their death, hypoxic zones are formed. To combat hypoxia, it is essential to reduce the amount of land-derived nutrients reaching rivers in runoff. This can be done by improving sewage treatment and by reducing the amount of fertilizers leaching into the rivers. Alternately, this can be done by restoring natural environments along a river; marshes are particularly effective in reducing the amount of phosphorus and nitrogen (nutrients) in water | https://en.wikipedia.org/wiki?curid=30872597 |
Hypoxia (environmental) Other natural habitat-based solutions include restoration of shellfish populations, such as oysters. Oyster reefs remove nitrogen from the water column and filter out suspended solids, subsequently reducing the likelihood or extent of harmful algal blooms or anoxic conditions. Foundational work toward the idea of improving marine water quality through shellfish cultivation was conducted by Odd Lindahl et al., using mussels in Sweden. More involved than single-species shellfish cultivation, integrated multi-trophic aquaculture mimics natural marine ecosystems, relying on polyculture to improve marine water quality. Technological solutions are also possible, such as that used in the redeveloped Salford Docks area of the Manchester Ship Canal in England, where years of runoff from sewers and roads had accumulated in the slow running waters. In 2001 a compressed air injection system was introduced, which raised the oxygen levels in the water by up to 300%. The resulting improvement in water quality led to an increase in the number of invertebrate species, such as freshwater shrimp, to more than 30. Spawning and growth rates of fish species such as roach and perch also increased to such an extent that they are now amongst the highest in England. In a very short time the oxygen saturation can drop to zero when offshore blowing winds drive surface water out and anoxic depth water rises up | https://en.wikipedia.org/wiki?curid=30872597 |
Hypoxia (environmental) At the same time a decline in temperature and a rise in salinity is observed (from the longterm ecological observatory in the seas at Kiel Fjord, Germany). New approaches of long-term monitoring of oxygen regime in the ocean observe online the behavior of fish and zooplankton, which changes drastically under reduced oxygen saturations (ecoSCOPE) and already at very low levels of water pollution. | https://en.wikipedia.org/wiki?curid=30872597 |
Planets in astrology have a meaning different from the modern astronomical understanding of what a planet is. Before the age of telescopes, the night sky was thought to consist of two very similar components: fixed stars, which remained motionless in relation to each other, and "wandering stars" ( "asteres planetai"), which moved relative to the fixed stars over the course of the year. To the Greeks and the other earliest astronomers, this group consisted of the five planets visible to the naked eye and excluded Earth. Although strictly, the term "planet" applied only to those five objects, the term was latterly broadened, particularly in the Middle Ages, to include the Sun and the Moon (sometimes referred to as "Lights"), making a total of seven planets. Astrologers retain this definition today. To ancient astrologers, the planets represented the will of the gods and their direct influence upon human affairs. To modern astrologers, the planets can represent basic drives or urges in the unconscious, or energy flow regulators representing dimensions of experience. They express themselves with different qualities in the twelve signs of the zodiac and in the twelve houses. The planets are also related to each other in the form of aspects. Modern astrologers differ on the source of the correlations between planetary positions and configurations, on the one hand, and characteristics and destinies of the natives, on the other. Hone writes that the planets exert it directly through gravitation or another, unknown influence | https://en.wikipedia.org/wiki?curid=30872816 |
Planets in astrology Others hold that the planets have no direct influence in themselves, but are mirrors of basic organizing principles in the universe. In other words, the basic patterns of the universe repeat themselves everywhere, in fractal-like fashion, and "as above, so below". Therefore, the patterns that the planets make in the sky reflect the ebb and flow of basic human impulses. The planets are also associated, especially in the Chinese tradition, with the basic forces of nature. Listed below are the specific meanings and domains associated with the astrological planets since ancient times, with the main focus on the Western astrological tradition. The planets in Hindu astrology are known as the Navagraha or "nine realms". In Chinese astrology, the planets are associated with the life forces of yin and yang and the five elements, which play an important role in the Chinese form of geomancy known as Feng Shui. Astrologers differ on the signs associated with each planet's exaltation. This table shows the astrological planets (as distinct from the astronomical) and the Greek and Roman deities associated with them. In most cases, the English name for planets derives from the name of a Roman god or goddess. Also of interest is the conflation of the Roman god with a similar Greek god. In some cases, it is the same deity with two different names. Treatises on the Ptolemaic planets and their influence on people born "under their reign" appear in block book form, so-called "planet books" or "Planetenbücher" | https://en.wikipedia.org/wiki?curid=30872816 |
Planets in astrology This genre is attested in numerous manuscripts beginning in the mid 15th century in the Alemannic German area; it remained popular throughout the German Renaissance, exerting great iconographical influence far into the 17th century. These books usually list a male and a female Titan with each planet, Cronus and Rhea with Saturn, Eurymedon and Themis with Jupiter, probably Crius and Dione with Mars, Hyperion and Theia with Sun, Atlas and Phoebe with Moon, Coeus and Metis with Mercury, and Oceanus and Tethys with Venus. The qualities inherited from the planets by their children are as follows: The seven classical planets are those easily seen with the naked eye, and were thus known to ancient astrologers. They are the Moon, Mercury, Venus, The Sun, Mars, Jupiter and Saturn. Sometimes, the Sun and Moon were referred to as "the lights" or the "luminaries". Vesta and Uranus can also just be seen with the naked eye, though no ancient culture appears to have taken note of them. The Classical planets fit neatly into the theories of Aristotle and Ptolemy, they each are part of a Celestial sphere. The order of the Classical planets is determined by the rate of speed. The Moon moves the fastest and so she is considered to form the first celestial sphere above earth. Everything below the moon is part of the sublunary sphere. Mercury moves the second fastest and so he rules the next highest sphere. Next is Venus, who takes about 260 days to revolve around the Sun. Following that is the Sun, then Mars, Jupiter and Saturn | https://en.wikipedia.org/wiki?curid=30872816 |
Planets in astrology The astrological descriptions attached to the seven classical planets have been preserved since ancient times. Astrologers call the seven classical planets "the seven personal and social planets", because they are said to represent the basic human drives of every individual. The personal planets are the Sun, Moon, Mercury, Venus and Mars. The social or transpersonal planets are Jupiter and Saturn. Jupiter and Saturn are often called the first of the "transpersonal" or "transcendent" planets as they represent a transition from the inner personal planets to the outer modern, impersonal planets. The outer modern planets Uranus, Neptune and Pluto are often called the collective or transcendental planets. The following is a list of the planets and their associated characteristics. The Moon () is the ruling planet of Cancer and is exalted in Taurus. In classical Roman mythology, the Moon was Luna, at times identified with Diana. The Moon is large enough for its gravity to affect the Earth, stabilizing its orbit and producing the regular ebb and flow of the tides. The lunar day syncs up with its orbit around Earth in such a manner that the same side of the Moon always faces the Earth and the other side, known as the "far side of the Moon" faces towards space. Astrologically speaking, the Moon is associated with a person's intuition, emotional make-up, unconscious habits, rhythms, memories, moods and their ability to react and adapt to those around them | https://en.wikipedia.org/wiki?curid=30872816 |
Planets in astrology It is associated for some with the mother, maternal instincts or the urge to nurture, the home, the need for security and the past, especially early experiences and childhood. The 1st-century poet Manilius described the Moon, or "Luna", as melancholic. In medicine, the Moon is associated with the digestive system, stomach, breasts, the ovaries and menstruation (which occurs on a monthly cycle) and the pancreas. Despite Manilius's assignment, the Moon is more commonly associated with the phlegmatic humor; it ruled the animal spirits. In modern astrology, the Moon is the primary native ruler of the fourth house, but traditionally it had its joy in the twelfth house. The Moon or "Luna" is associated with Monday, the word Monday comes from the Old English word for Moon day or Moon's day, and in Romance languages, the name for Monday comes from "luna" (e.g., "luni" in Romanian, "lundi" in French, "lunes" in Spanish and "lunedi" in Italian). Dante Alighieri associated the Moon with the liberal art of grammar. In Chinese astrology, the Moon represents Yin, the passive and receptive feminine life principle. In Indian astrology, the Moon is called Chandra or Soma and represents the mind, queenship and mother. The north lunar node (called Rahu) and the south lunar node (called Ketu) are considered to be of particular importance and are given an equal place alongside the seven classical planets as part of the nine navagraha. Mercury () is the ruling planet of Gemini and is exalted in Virgo and Aquarius | https://en.wikipedia.org/wiki?curid=30872816 |
Planets in astrology In classical Roman mythology, Mercury is the messenger of the gods, noted for his speed and swiftness. Echoing this, the scorching, airless world Mercury circles the Sun on the fastest orbit of any planet. Mercury takes only 88 days to orbit the Sun, spending about 7.33 days in each sign of the zodiac. Mercury is so close to the Sun that only a brief period exists after the Sun has set where it can be seen with the naked eye, before following the Sun beyond the horizon. Astrologically speaking, Mercury represents the principles of communication, mentality, thinking patterns, rationality and reasoning, and adaptability and variability. Mercury governs schooling and education, the immediate environment of neighbors, siblings and cousins, transport over short distances, messages and forms of communication such as post, email and telephone, newspapers, journalism and writing, information gathering skills and physical dexterity. The 1st-century poet Marcus Manilius described Mercury as an inconstant, vivacious and curious planet. In medicine, Mercury is associated with the nervous system, the brain, the respiratory system, the thyroid and the sense organs. It is traditionally held to be essentially cold and dry, according to its placement in the zodiac and in any aspects to other planets. In modern astrology, Mercury is regarded as the ruler of the third house; traditionally, it had the joy in the eleventh house. Mercury is the messenger of the gods in mythology | https://en.wikipedia.org/wiki?curid=30872816 |
Planets in astrology It is the planet of day-to-day expression and relationships. Mercury's action is to take things apart and put them back together again. It is an opportunistic planet, decidedly unemotional and curious. Mercury rules over Wednesday. In Romance languages, the word for Wednesday is often similar to Mercury ("miercuri" in Romanian, "mercredi" in French, "miercoles" in Spanish and "mercoledì" in Italian). Dante Alighieri associated Mercury with the liberal art of dialectic. In Chinese astrology Mercury represents Water, the fourth element, therefore symbolizing communication, intelligence, and elegance. Venus () is the traditional ruling planet of Libra and Taurus and is exalted in Pisces. In classical Roman mythology, Venus is the goddess of love and beauty, famous for the passions she could stir among the gods. Her cults may represent the religiously legitimate charm and seduction of the divine by mortals, in contrast to the formal, contractual relations between most members of Rome's official pantheon and the state, and the unofficial, illicit manipulation of divine forces through magic. The ambivalence of her function is suggested in the etymological relationship of the root *venes- with Latin venenum (poison, venom), in the sense of "a charm, magic philtre". Venus orbits the Sun in 225 days, spending about 18.75 days in each sign of the zodiac. Venus is the second-brightest object in the night sky, the Moon being the brightest. It is usually beheld as a twin planet to Earth | https://en.wikipedia.org/wiki?curid=30872816 |
Planets in astrology Astrologically speaking, Venus is associated with the principles of harmony, beauty, refinement, affections, and the urge to sympathize and unite with others. It is involved with the desire for pleasure, comfort and ease. It governs romantic relations, marriage and business partnerships, sex (the origin of the words 'venery' and 'venereal'), the arts, fashion and social life. The 1st-century poet Marcus Manilius described Venus as generous and fecund and the lesser benefic. The planet Venus in medicine is associated with the lumbar region, the veins, parathyroids, throat and kidneys. Venus was thought to be moderately warm and moist and was associated with the phlegmatic humor. In modern astrology, Venus is the ruler of the seventh house; traditionally, it had the joy in the fourth house. Venus is the planet of Friday. In languages deriving from Latin, such as Romanian, Spanish, French, and Italian, the word for Friday often resembles the word Venus ("vineri", "viernes", "vendredi" and "venerdì" respectively). Dante Alighieri associated Venus with the liberal art of rhetoric. In Chinese astrology, Venus is associated with the element metal, which is unyielding, strong and persistent. In Indian astrology, Venus is known as Shukra and represents wealth, pleasure and reproduction. In Norse Paganism, the planet is associated to Freyja, the goddess of love, beauty and fertility. The Sun () is the ruling planet of Leo and is exalted in Aries | https://en.wikipedia.org/wiki?curid=30872816 |
Planets in astrology In classical Greek mythology, the Sun was represented by the Titans Hyperion and Helios (Roman Sol, and later by Apollo, the god of light). The Sun is the star at the center of our solar system, around which the Earth and other planets revolve and provides us with heat and light. The arc that the Sun travels in every year, rising and setting in a slightly different place each day, is therefore in reality a reflection of the Earth's own orbit around the Sun. This arc is larger the farther north or south from the equator latitude, giving a more extreme difference between day and night and between seasons during the year. The Sun travels through the twelve signs of the zodiac on its annual journey, spending about a month in each. The Sun's position on a person's birthday therefore determines what is usually called his or her "sun" sign. However, the sun sign allotment varies between Western (sign change around 22-23 of every month) and Hindu astrology (sign change around 14-15 of every month) due the different systems of planetary calculations, following the tropical and sidereal definitions respectively. Astrologically speaking, the Sun is usually thought to represent the conscious ego, the self and its expression, personal power, pride and authority, leadership qualities and the principles of creativity, spontaneity, health and vitality, the sum of which is named the "life force". One of the first recorded references to Sun worship is from the Mesopotamian Religion and described in the Epic of Gilgamesh | https://en.wikipedia.org/wiki?curid=30872816 |
Planets in astrology The 1st-century poet Marcus Manilius in his epic, 8000-verse poem, "Astronomica", described the Sun, or "Sol", as benign and favorable. In medicine, the Sun is associated with the heart, circulatory system, and the thymus. Additionally, humans depend on the sun to produce and obtain vitamin D; an important supplement aiding the body's immune system and bone health. In Ayurveda, it rules over life-force (praan-shakti), governs bile temperament (pitta), stomach, bones and eyes. In modern astrology, the Sun is the primary native ruler of the fifth house, but traditionally it had its joy in the ninth house. The Sun is associated with Sunday. Dante Alighieri associated the Sun with the liberal art of music. In Chinese astrology, the Sun represents Yang, the active, assertive masculine life principle. Mars () is the traditional ruling planet of Aries and Scorpio and is exalted in Capricorn. Mars is the Roman god of war and bloodshed, whose symbol is a spear and shield. Both the soil of Mars and the hemoglobin of human blood are rich in iron and because of this they share its distinct deep red color. He was second in importance only to Jupiter and Saturn, due to Mars being the most prominent of the military gods worshipped by the Roman legions. Mars orbits the Sun in 687 days, spending about 57.25 days in each sign of the zodiac. It is also the first planet that orbits outside of Earth's orbit, making it the first planet that does not set along with the Sun. Mars has two permanent polar ice caps | https://en.wikipedia.org/wiki?curid=30872816 |
Planets in astrology During a pole's winter, it lies in continuous darkness, chilling the surface and causing the deposition of 25–30% of the atmosphere into slabs of CO ice (dry ice). Astrologically speaking, Mars is associated with confidence and self-assertion, aggression, confrontation, sexuality, energy, strength, ambition and impulsiveness. Mars governs sports, competitions and physical activities in general. The 1st-century poet Manilius, described the planet as ardent and as the lesser malefic. In medicine, Mars presides over the genitals, the muscular system, the gonads and adrenal glands. It was traditionally held to be hot and excessively dry and ruled the choleric humor. It was associated with fever, accidents, trauma, pain and surgery. In modern astrology, Mars is the primary native ruler of the first house. Traditionally however, Mars ruled both the third and tenth houses, and had its joy in the fifth house. While Venus tends to the overall relationship atmosphere, Mars is the passionate impulse and action, the masculine aspect, discipline, willpower and stamina. Mars is associated with Tuesday and in Romance languages the word for Tuesday often resembles Mars (in Romanian, "marţi", in Spanish, "martes", in French, "mardi" and in Italian "martedì"). The English "Tuesday" is a modernised form of "Tyr's Day", Tyr being the Germanic analogue to Mars. Dante Alighieri associated Mars with the liberal art of arithmetic. In Chinese astrology, Mars is ruled by the element fire, which is passionate, energetic and adventurous | https://en.wikipedia.org/wiki?curid=30872816 |
Planets in astrology In Indian astrology, Mars is called Mangala and represents energy, confidence and ego. Jupiter () is the traditional ruling planet of Sagittarius and Pisces and it is exalted in Cancer. In classical Roman mythology, Jupiter is the ruler of the gods and their guardian and protector, and his symbol is the thunderbolt. The Romans believed that Jupiter granted them supremacy because they had honored him more than any other people had. Jupiter was "the fount of the auspices upon which the relationship of the city with the gods rested." He personified the divine authority of Rome's highest offices, internal organization, and external relations. His image in the Republican and Imperial Capitol bore regalia associated with Rome's ancient kings and the highest consular and Imperial honours. In the same way, the planet Jupiter is the king of the other planets, a giant in size with spectacular, brightly colored clouds and intense storms. Some astronomers believe that it plays an important protecting role in using its massive gravity to capture or expel from the solar system many comets and asteroids that would otherwise threaten Earth and the inner planets. Jupiter takes 11.9 years to orbit the Sun, spending almost an earth year (361 days) in each sign of the zodiac. Furthermore, Jupiter is usually the fourth-brightest object in the sky (after the Sun, the Moon and Venus). Astrologically speaking, Jupiter is associated with the principles of growth, expansion, healing, prosperity, good fortune, and miracles | https://en.wikipedia.org/wiki?curid=30872816 |
Planets in astrology Jupiter governs long distance and foreign travel, big business and wealth, higher education, religion, and the law. It is also associated with the urge for freedom and exploration, as well with gambling and merrymaking. The 1st-century poet Manilius described Jupiter as temperate and benign, and the greater benefic. It was regarded as warm and moist in nature, and therefore favorable to life. In medicine, Jupiter is associated with the liver, pituitary gland, and the disposition of fats; it governed the sanguine humor. In modern astrology, Jupiter is the primary native ruler of the ninth house, but traditionally, Jupiter was assigned to both the second and ninth houses: the house of values and the house of beliefs, respectively, and had its joy in the second house of good luck. Jupiter is associated with Thursday, and in Romance languages, the name for Thursday often comes from Jupiter (e.g., "joi" in Romanian, "jeudi" in French, "jueves" in Spanish, and "giovedì" in Italian). Dante Alighieri associated Jupiter with the liberal art of geometry. In Chinese astrology, Jupiter is ruled by the element wood, which is patient, hard-working, and reliable. In Indian astrology, Jupiter is known as Guru or Brihaspati and is known as the 'great teacher'. Saturn () is the traditional ruling planet of Capricorn and Aquarius and is exalted in Libra | https://en.wikipedia.org/wiki?curid=30872816 |
Planets in astrology In classical Roman mythology, Saturn is the god of seeds, crops, and the harvest (agriculture), leader of the titans, father and founder of civilizations, social order, and conformity. The glyph is shaped like a scythe, but it is known as the "crescent below the cross", whereas Jupiter's glyph is the "crescent above the cross". Famous rings of the planet Saturn that enclose and surround it, reflect the idea of human limits. Saturn takes 29.5 years to orbit the Sun, spending about 2.46 years in each sign of the zodiac. During ancient Roman society, the Romans worshipped Saturn as the highest ranking and most important god among their pantheon of deities, sharing that same prestige with Jupiter. Astrologically speaking, Saturn is associated with focus, precision, nobility, ethics, civility, lofty goals, career, great achievements, dedication, authority figures, stability, virtues, productiveness, valuable hard lessons learned, destiny, structures, protective roles, balance, conservatism, and karma (reaping what you have sowed or divine cosmic justice) but with limitations, restrictions, boundaries, anxiety, tests, practicality, reality, and time. It concerns a person's sense of duty, commitment, responsibility, including their physical and emotional endurance in times of hardships. Saturn is fundamentally economical. Also represents the part of a person's concern with long-term planning or foresight. The Return of Saturn is said to mark significant events in each person's life | https://en.wikipedia.org/wiki?curid=30872816 |
Planets in astrology According to the 1st-century poet Manilius, Saturn is sad, morose, and cold, and is the greater malefic. According to Claudius Ptolemy, "Saturn is lord of the right ear, the spleen, the bladder, the phlegm, and the bones." Saturn symbolized processes and things that were dry and cold, which are necessary balancing aspects to maintain life. It governed the melancholic humor. According to Sefer Yetzirah – GRA Version – Kaplan 4:13 "He made the letter Resh king over Peace And He bound a crown to it And He combined one with another And with them He formed Saturn in the Universe Friday in the Year The left nostril in the Soul, male and female." Before the discovery of Uranus, Saturn was regarded as the ruling planet of Aquarius alongside Capricorn, which is the preceding sign. Many traditional types of astrologers refer to Saturn as the planetary ruler for both Capricorn and Aquarius. In modern astrology, it is the primary native ruler of the tenth house. In traditional Hindu astrology however, Saturn ruled both the first and eighth houses, and had its joy in the sixth house of mischief and bad luck. Saturn is associated with Saturday, which was named after the deity Saturn. Dante Alighieri associated Saturn with the liberal art of "astronomia" (astronomy and astrology). In Chinese astrology, Saturn is ruled by the element earth, which is warm, generous, and co-operative. In Indian astrology, Saturn is called Shani or "Sani", representing a noteworthy career and longevity | https://en.wikipedia.org/wiki?curid=30872816 |
Planets in astrology He is also the bringer of obstacles and hardship. Since the invention of the telescope, Western astrology has incorporated Uranus, Neptune, Ceres, Pluto, and other bodies into its methodology. The Indian and Chinese astrologies have tended to retain the ancient seven-planet system. Meanings have had to be assigned to them by modern astrologers, usually according to the major events that occurred in the world at the time of their discovery. As these astrologers are usually Western, the social and historical events they describe have an inevitable Western emphasis. Astrologers consider the "extra-Saturnian" planets to be "impersonal" or generational planets, meaning their effects are felt more across whole generations of society. Their effects in individuals depend upon how strongly they feature in that individual's birth-chart. The following are their characteristics as accepted by most astrologers. Uranus () is the modern ruling planet of Aquarius and is exalted in Scorpio. In classical Greek mythology, Uranus is the personification of the sky. The planet Uranus is very unusual among the planets in that it rotates on its side, so that it presents each of its poles to the Sun in turn during its orbit; causing both hemispheres to alternate between being bathed in light and lying in total darkness over the course of the orbit. Uranus takes 84 years to orbit the Sun, spending about 7 years in each sign of the zodiac. Uranus was discovered to be a planet only in 1781 by Sir William Herschel | https://en.wikipedia.org/wiki?curid=30872816 |
Planets in astrology Astrological interpretations associate Uranus with the principles of ingenuity, new or unconventional ideas, individuality, discoveries, electricity, inventions, democracy, and revolutions. Uranus, among all planets, most governs genius. Uranus governs societies, clubs, and any group based on humanitarian or progressive ideals. Uranus, the planet of sudden and unexpected changes, rules freedom and originality. In society, it rules radical ideas and people, as well as revolutionary events that upset established structures. Uranus is also associated with Wednesday, alongside Mercury (since Uranus is in the higher octave of Mercury). In art and literature, the discovery of Uranus coincided with the Romantic movement, which emphasized individuality and freedom of creative expression. Additionally, it is often linked to an individual's animal spirit. When it comes to medicine, Uranus is believed to be particularly associated with the sympathetic nervous system, mental disorders, breakdowns and hysteria, spasms, and cramps. Uranus is considered by modern astrologers to be the primary native ruler of the eleventh house. Neptune () is the modern ruling planet of Pisces and is exalted in Leo. In classical Roman mythology, Neptune is the god of the sea, and the deep, ocean blue color of the planet Neptune reflects this. Its glyph is taken directly from Neptune's trident, symbolizing the curve of spirit being pierced by the cross of matter. Neptune takes 165 years to orbit the Sun, spending approximately 14 years (13 | https://en.wikipedia.org/wiki?curid=30872816 |
Planets in astrology 75) in each sign of the zodiac. Neptune was discovered in 1846. Astrologically speaking, Neptune is associated with the collective consciousness, idealism, dreams/fantasy, projections, undoing/dissolution of the status quo, artistry, empathy, and illusion/confusion/vagueness on the way to discovering universal truths. Like with Venus, the planet Neptune is also associated with Friday because Neptune is the higher octave of Venus. In art, the impressionist movement began a trend away from literal representation, to one based on the subtle, changing moods of light and color. In medicine, Neptune is seen to be particularly associated with the thalamus, the spinal canal, and uncertain illnesses or neuroses. Neptune is considered by modern astrologers to be the primary ruler of the twelfth house. Pluto () is the modern ruling planet of Scorpio and is exalted in Virgo. In classical Roman mythology, Pluto is the god of the underworld who is extremely wealthy. The alchemical symbol was given to Pluto on its discovery, three centuries after alchemical practices had all but disappeared. The alchemical symbol can therefore be read as spirit over mind, transcending matter. Pluto takes 248 years to make a full circuit of the zodiac, but its progress is highly variable: it spends between 15 and 26 years in each sign | https://en.wikipedia.org/wiki?curid=30872816 |
Planets in astrology Astrologically speaking, Pluto is called "the great renewer" and is considered to represent the part of a person that destroys in order to renew by being buried, bringing intense needs and drives to the surface, and expressing them, even at the expense of the existing order. A commonly used keyword for Pluto is "transformation". It is associated with absolutes, power, extremities, transformations, evolutions, incredible feats, mass movements, and the need to cooperate or share with another if each is not to be destroyed. Pluto governs major business and enormous wealth, mining, surgery and detective work, and any enterprise that involves digging under the surface to bring the truth to light. Pluto is also associated with Tuesday, alongside Mars since Pluto is the higher octave of that planet in astrology. Its entry in Cancer in 1914, the sign in which it was later discovered, coincided with World War I. It is also associated with nuclear armament due to such weapons using plutonium, which was named after the dwarf planet. Nuclear research had its genesis in the 1930s and 40s and later gave rise to the polarized nuclear standoff of the Cold War, with the mass consumer societies of the United States and other democracies facing the totalitarian state of the USSR. The discovery of Pluto also occurred just after the birth of modern psychoanalysis, when Freud and Jung began to explore the depths of the unconscious. In real life events and culture, Pluto has been a major astrological aspect | https://en.wikipedia.org/wiki?curid=30872816 |
Planets in astrology When it comes to art, movements like Cubism and Surrealism began to de-construct the "normal" view of the world. In medicine, Pluto is seen to be associated with regenerative forces in the body involving cell formation and the reproductive system. The majority of traditional astrologers do not use Pluto as a ruling planet, but do use the planet for interpretation and predictive work, obliquely making reference to projections of influences from higher to lower dimensional spaces. Pluto is considered by modern astrologers to be the primary native ruler of the eighth house and a higher octave of Mars that functions on a collective level. Ceres () is the smallest identified dwarf planet in the solar system, but is significantly the largest object in the asteroid belt. It was discovered on 1 January 1801 by Giuseppe Piazzi, and is named after Ceres, the Roman goddess of growing plants, the harvest, and of motherly love. It was the first asteroid discovered, taking up about one-third of the entire mass of its asteroid belt. The classification of Ceres has changed more than once and has been the subject of some disagreement. Johann Elert Bode believed Ceres to be the "missing planet" he had proposed to exist between Mars and Jupiter, at a distance of 419 million km (2.8 AU) from the Sun. Ceres was assigned a planetary symbol, and remained listed as a planet in astronomy books and tables for about half a century | https://en.wikipedia.org/wiki?curid=30872816 |
Planets in astrology The 2006 debate surrounding Pluto and what constitutes a planet led to Ceres being considered for reclassification as a planet, but in the end, Ceres and Pluto were classified as the first members of the new dwarf planet category. Ceres passes through the zodiac every 4 years and 7 months, passing through a little more than 2½ signs every year. In mythology, Ceres is the Roman equivalent of the Greek goddess Demeter, and is the goddess of agriculture. The goddess (and metaphorically the planet) is also associated with the reproductive issues of an adult woman, as well as pregnancy and other major transitions in a woman's life, including the nine months of gestation time, family bonds and relationships. In the early 1800's after its discovery, , Ceres was seen as the ruling planet of Virgo. Due to its mythological connection to the harvest cycle, some modern astrologers feel Ceres should be the ruler of Taurus, however, many European astrologers see Ceres as ruling Virgo with its observed connection to the practical, being of service and assisting. Although a mother, Ceres is also the archetype of a virgin goddess which is associated with Virgo. Ceres may be epitomized by independent women who are often unmarried (since, according to myth, Ceres is an unmarried goddess who chose to become a mother without a husband or partner.) While the moon represents our ideal of "motherhood", Ceres would represent how our real and natural motherhood should be | https://en.wikipedia.org/wiki?curid=30872816 |
Planets in astrology In point of fact, Ceres is often observed in strong aspect in the synastry of parents and children as well as marriage partners' charts. Ceres, as the Goddess who has control over nature's resources and cycles, may astrologically be considered the planet of the Environment. Returning to mythology, an early environmental villain is the figure of Erysichthon, the tearer up of the earth, who cut down trees in a grove sacred to Ceres-Demeter, for which he was punished by the goddess with fearful hunger. In this sense, Ceres became an emerging archetype in the awareness of climate change in the 21st century and is entering the collective consciousness as a need to take care of our natural and irreplaceable resources. Ceres represents a leap towards a future of ecological responsibility and knowledge. As an indicator for environmental or community activism, Ceres would represent for some astrologers the wave of the future. Some asteroids such as Pallas () and Vesta (), as well as dwarf planet Ceres, can sometimes be seen with binoculars (Vesta even with the naked eye), but these were not recognized as planetary, and perhaps not even noticed, until the early 19th century. In the early 19th century, Ceres, Juno (), and the other two aforementioned asteroids were for a time regarded as planets. Although asteroids have been known to both astronomers and astrologers for more than 200 years, they are often ignored by astrologers | https://en.wikipedia.org/wiki?curid=30872816 |
Planets in astrology The tradition of some astrologers casting charts with minor planets originates with these asteroids. Since the discovery of Chiron () in the 1970s, some astrologers have been casting the new "planet", although astronomers consider it a centaur (a kind of intermediate object between comet and asteroid). In the 21st century, several new planet-sized bodies, including Sedna, Quaoar, Haumea, and Eris, have been discovered, but not yet incorporated into mainstream astrological predictions, although some more avant-garde groups have attempted to incorporate them. Some astrologers have hypothesized about the existence of unseen or undiscovered planets. In 1918, astrologer Sepharial proposed the existence of Earth's "Dark Moon" Lilith, and since then, some astrologers have been using it in their charts; though the same name is also (and now, more commonly) used in astrology to refer to the axis of the actual Moon's orbit. The 20th-century German school of astrology known as Uranian astrology also claimed that many undiscovered planets existed beyond the orbit of Neptune, giving them names such as Cupido, Hades, Zeus, Kronos, Apollon, Admetos, Vulcanus, and Poseidon, and charting their supposed orbits. These orbits have not coincided, however, with more recent discoveries by astronomers of objects beyond Neptune | https://en.wikipedia.org/wiki?curid=30872816 |
Planets in astrology Other astrologers have focused on the theory that in time, all twelve signs of the zodiac will each have their own ruler, so that another two planets have yet to be discovered; namely the "true" rulers of Taurus and Virgo. The names of the planets mentioned in this regard by some are Vulcan (ruler of Virgo) and Apollo, the Roman god of the Sun (ruler of Taurus). Another version of this theory states that the modern planets discovered so far correspond to the elements known to the ancients—air (Uranus, god of the heavens), water (Neptune, god of the sea), and fire (Pluto, god of the underworld)—which leaves the elements earth and ether (the fifth element of the fiery upper air). In other words, it is claimed that the two planets to be discovered will be named after an earth god or goddess (such as the Horae), and after Aether, the Roman and Greek god of the upper air and stars. In Western astrology, the symbolism associated with the planets also relates to the zodiac signs and houses of the horoscope in their various rulerships. For instance, the description of Mars is masculine, impulsive, and active. Aries is ruled by Mars and has a similar description, representing an active, masculine archetype. Similarly, the first house is also ruled by Mars, and deals with a person's physical health and strength, and the manner in which they project themselves | https://en.wikipedia.org/wiki?curid=30872816 |
Planets in astrology Table 1: Modern signs, houses and planetary associations "Note": The planets in the table rule the signs on the same row, and the houses do correspond with the signs on the same row (i.e. Mars rules Aries; Aries and first house share some correspondences). However, it is only modern astrology that links the planets to the houses in this order. The bulk of the tradition assigns planetary rulerships according to the ancient Chaldean astronomical order of the planets (Saturn, Jupiter, Mars, Sun, Venus, Mercury, Moon; the former order of the planets in distance from Earth geocentrically): Table 2: Traditional Chaldean houses and planetary relationships. | https://en.wikipedia.org/wiki?curid=30872816 |
De la pirotechnia De la Pirotechnia is considered to be the first printed book on metallurgy to have been published in Europe. It was written in Italian and first published in Venice in 1540. The author was Vannoccio Biringuccio, a citizen of Siena, Italy, who died before it was published. Further editions were published in 1550, 1558, 1559, and 1678, with a (sloppy) French translation by Jacques Vincent being published in 1556, 1572, and 1627. Parts were translated into Latin (by Georgius Agricola), English (Richard Eden; Peter Whitehorn) and Spanish (Bernardo Perez de Vargas) at various times in the 1550s and 1560s, generally without acknowledgement. The second book on metallurgy, "De re metallica", was written in Latin by Georgius Agricola, and published in 1556. Both "De la pirotechnia" and "De re metallica" were translated into English in the 20th century. The translation of "Pirotechnia" was by Cyril Stanley Smith, a senior chemist on the Manhattan Project, and Martha Teach Gnudi. Both books were illustrated with extensive, beautiful woodcuts. The majority of the work is devoted to the more technical aspects of metalworking (such as the mining, assaying and smelting of ores), but Biringuccio also provides insights into the humanistic philosophy of the Italian Renaissance. Alchemy is also discussed. | https://en.wikipedia.org/wiki?curid=30874214 |
Equivalent (chemistry) An equivalent (symbol: officially equiv; unofficially but often Eq) is the amount of a substance that reacts with (or is "equivalent" to) an arbitrary amount of another substance in a given chemical reaction. It is an archaic unit of measurement that was used in chemistry and the biological sciences in the era before researchers knew how to determine the chemical formula for a compound. The mass of an equivalent is called its equivalent weight. In a more formal definition, the "equivalent" is the amount of a substance needed to do one of the following: By this definition, an "equivalent" is the number of moles of an ion in a solution, multiplied by the valence of that ion. If 1 mol of NaCl and 1 mol of CaCl dissolve in a solution, there is 1 equiv Na, 2 equiv Ca, and 3 equiv Cl in that solution. (The valence of calcium is 2, so for that ion you have 1 mole and 2 equivalents.) An earlier definition, used especially for chemical elements, holds that an equivalent is the amount of a substance that will react with of hydrogen, of oxygen, or of chlorine—or that will displace any of the three. In practice, the amount of a substance in equivalents often has a very small magnitude, so, especially in medicine, it is routinely described in terms of milliequivalents (symbol: officially mequiv; unofficially but often mEq or meq), the prefix milli- denoting that the measure has been multiplied by 1000. Very often, the measure is used in terms of milliequivalents of solute per litre of solution (or milliNormal, where ) | https://en.wikipedia.org/wiki?curid=30875016 |
Equivalent (chemistry) This is especially common for measurement of compounds in biological fluids; for instance, the healthy level of potassium in the blood of a human is defined between 3.5 and 5.0 mEq/L. A certain amount of univalent ions provides the same amount of equivalents while the same amount of divalent ions provides twice the amount of equivalents. For example, 1 mmol (0.001 mol) of Na is equal 1 meq, while 1 mmol of Ca is equal 2 meq. | https://en.wikipedia.org/wiki?curid=30875016 |
Plant breeding is the science of changing the traits of plants in order to produce desired characteristics. It has been used to improve the quality of nutrition in products for humans and animals. can be accomplished through many different techniques ranging from simply selecting plants with desirable characteristics for propagation, to methods that make use of knowledge of genetics and chromosomes, to more complex molecular techniques (see cultigen and cultivar). Genes in a plant are what determine what type of qualitative or quantitative traits it will have. Plant breeders strive to create a specific outcome of plants and potentially new plant varieties. has been practiced for thousands of years, since near the beginning of human civilization. It is practiced worldwide by individuals such as gardeners and farmers, and by professional plant breeders employed by organizations such as government institutions, universities, crop-specific industry associations or research centers. International development agencies believe that breeding new crops is important for ensuring food security by developing new varieties that are higher yielding, disease resistant, drought tolerant or regionally adapted to different environments and growing conditions. started with sedentary agriculture and particularly the domestication of the first agricultural plants, a practice which is estimated to date back 9,000 to 11,000 years | https://en.wikipedia.org/wiki?curid=30876044 |
Plant breeding Initially early farmers simply selected food plants with particular desirable characteristics, and employed these as progenitors for subsequent generations, resulting in an accumulation of valuable traits over time. Grafting technology had been practiced in China before 2000 BCE. By 500 BCE grafting was well established and practiced. Gregor Mendel (1822–84) is considered the "father of genetics". His experiments with plant hybridization led to his establishing laws of inheritance. Genetics stimulated research to improve crop production through plant breeding. Modern plant breeding is applied genetics, but its scientific basis is broader, covering molecular biology, cytology, systematics, physiology, pathology, entomology, chemistry, and statistics (biometrics). It has also developed its own technology. One major technique of plant breeding is selection, the process of selectively propagating plants with desirable characteristics and eliminating or "culling" those with less desirable characteristics. Another technique is the deliberate interbreeding (crossing) of closely or distantly related individuals to produce new crop varieties or lines with desirable properties. Plants are crossbred to introduce traits/genes from one variety or line into a new genetic background. For example, a mildew-resistant pea may be crossed with a high-yielding but susceptible pea, the goal of the cross being to introduce mildew resistance without losing the high-yield characteristics | https://en.wikipedia.org/wiki?curid=30876044 |
Plant breeding Progeny from the cross would then be crossed with the high-yielding parent to ensure that the progeny were most like the high-yielding parent, (backcrossing). The progeny from that cross would then be tested for yield (selection, as described above) and mildew resistance and high-yielding resistant plants would be further developed. Plants may also be crossed with themselves to produce inbred varieties for breeding. Pollinators may be excluded through the use of pollination bags. Classical breeding relies largely on homologous recombination between chromosomes to generate genetic diversity. The classical plant breeder may also make use of a number of "in vitro" techniques such as protoplast fusion, embryo rescue or mutagenesis (see below) to generate diversity and produce hybrid plants that would not exist in nature. Traits that breeders have tried to incorporate into crop plants include: Successful commercial plant breeding concerns were founded from the late 19th century. Gartons Agricultural Plant Breeders in England was established in the 1890s by John Garton, who was one of the first to commercialize new varieties of agricultural crops created through cross-pollination. The firm's first introduction was Abundance Oat, one of the first agricultural grain varieties bred from a "controlled" cross, introduced to commerce in 1892 | https://en.wikipedia.org/wiki?curid=30876044 |
Plant breeding In the early 20th century, plant breeders realized that Mendel's findings on the non-random nature of inheritance could be applied to seedling populations produced through deliberate pollinations to predict the frequencies of different types. Wheat hybrids were bred to increase the crop production of Italy during the so-called "Battle for Grain" (1925–1940). Heterosis was explained by George Harrison Shull. It describes the tendency of the progeny of a specific cross to outperform both parents. The detection of the usefulness of heterosis for plant breeding has led to the development of inbred lines that reveal a heterotic yield advantage when they are crossed. Maize was the first species where heterosis was widely used to produce hybrids. Statistical methods were also developed to analyze gene action and distinguish heritable variation from variation caused by environment. In 1933 another important breeding technique, cytoplasmic male sterility (CMS), developed in maize, was described by Marcus Morton Rhoades. CMS is a maternally inherited trait that makes the plant produce sterile pollen. This enables the production of hybrids without the need for labor-intensive detasseling. These early breeding techniques resulted in large yield increase in the United States in the early 20th century. Similar yield increases were not produced elsewhere until after World War II, the Green Revolution increased crop production in the developing world in the 1960s | https://en.wikipedia.org/wiki?curid=30876044 |
Plant breeding Following World War II a number of techniques were developed that allowed plant breeders to hybridize distantly related species, and artificially induce genetic diversity. When distantly related species are crossed, plant breeders make use of a number of plant tissue culture techniques to produce progeny from otherwise fruitless mating. Interspecific and intergeneric hybrids are produced from a cross of related species or genera that do not normally sexually reproduce with each other. These crosses are referred to as "Wide crosses". For example, the cereal triticale is a wheat and rye hybrid. The cells in the plants derived from the first generation created from the cross contained an uneven number of chromosomes and as result was sterile. The cell division inhibitor colchicine was used to double the number of chromosomes in the cell and thus allow the production of a fertile line. Failure to produce a hybrid may be due to pre- or post-fertilization incompatibility. If fertilization is possible between two species or genera, the hybrid embryo may abort before maturation. If this does occur the embryo resulting from an interspecific or intergeneric cross can sometimes be rescued and cultured to produce a whole plant. Such a method is referred to as Embryo Rescue. This technique has been used to produce new rice for Africa, an interspecific cross of Asian rice "(Oryza sativa)" and African rice "(Oryza glaberrima)". Hybrids may also be produced by a technique called protoplast fusion | https://en.wikipedia.org/wiki?curid=30876044 |
Plant breeding In this case protoplasts are fused, usually in an electric field. Viable recombinants can be regenerated in culture. Chemical mutagens like EMS and DMS, radiation and transposons are used to generate mutants with desirable traits to be bred with other cultivars – a process known as "Mutation Breeding". Classical plant breeders also generate genetic diversity within a species by exploiting a process called somaclonal variation, which occurs in plants produced from tissue culture, particularly plants derived from callus. Induced polyploidy, and the addition or removal of chromosomes using a technique called chromosome engineering may also be used. When a desirable trait has been bred into a species, a number of crosses to the favored parent are made to make the new plant as similar to the favored parent as possible. Returning to the example of the mildew resistant pea being crossed with a high-yielding but susceptible pea, to make the mildew resistant progeny of the cross most like the high-yielding parent, the progeny will be crossed back to that parent for several generations (See backcrossing ). This process removes most of the genetic contribution of the mildew resistant parent. Classical breeding is therefore a cyclical process. With classical breeding techniques, the breeder does not know exactly what genes have been introduced to the new cultivars. Some scientists therefore argue that plants produced by classical breeding methods should undergo the same safety testing regime as genetically modified plants | https://en.wikipedia.org/wiki?curid=30876044 |
Plant breeding There have been instances where plants bred using classical techniques have been unsuitable for human consumption, for example the poison solanine was unintentionally increased to unacceptable levels in certain varieties of potato through plant breeding. New potato varieties are often screened for solanine levels before reaching the marketplace. Modern plant breeding may use techniques of molecular biology to select, or in the case of genetic modification, to insert, desirable traits into plants. Application of biotechnology or molecular biology is also known as molecular breeding. Sometimes many different genes can influence a desirable trait in plant breeding. The use of tools such as molecular markers or DNA fingerprinting can map thousands of genes. This allows plant breeders to screen large populations of plants for those that possess the trait of interest. The screening is based on the presence or absence of a certain gene as determined by laboratory procedures, rather than on the visual identification of the expressed trait in the plant. The purpose of marker assisted selection, or plant genomes analysis, is to identify the location and function (phenotype) of various genes within the genome. If all of the genes are identified it leads to Genome sequence. All plants have varying sizes and lengths of genomes with genes that code for different proteins, but many are also the same | https://en.wikipedia.org/wiki?curid=30876044 |
Plant breeding If a gene's location and function is identified in one plant species, a very similar gene likely can also be found in a similar location in another species genome. Homozygous plants with desirable traits can be produced from heterozygous starting plants, if a haploid cell with the alleles for those traits can be produced, and then used to make a doubled haploid. The doubled haploid will be homozygous for the desired traits. Furthermore, two different homozygous plants created in that way can be used to produce a generation of F1 hybrid plants which have the advantages of heterozygosity and a greater range of possible traits. Thus, an individual heterozygous plant chosen for its desirable characteristics can be converted into a heterozygous variety (F1 hybrid) without the necessity of vegetative reproduction but as the result of the cross of two homozygous/doubled haploid lines derived from the originally selected plant. Using plant tissue culturing can produce haploid or double haploid plant lines and generations. This minimizes the amount of genetic diversity among that plant species in order to select for desirable traits that will increase the fitness of the individuals. Using this method decreases the need for breeding multiple generations of plants to get a generation that is homologous for the desired traits, therefore save much time in the process | https://en.wikipedia.org/wiki?curid=30876044 |
Plant breeding There are many plant tissue culturing techniques that can be used to achieve the haploid plants, but microspore culturing is currently the most promising for producing the largest numbers of them. Genetic modification of plants is achieved by adding a specific gene or genes to a plant, or by knocking down a gene with RNAi, to produce a desirable phenotype. The plants resulting from adding a gene are often referred to as transgenic plants. If for genetic modification genes of the species or of a crossable plant are used under control of their native promoter, then they are called cisgenic plants. Sometimes genetic modification can produce a plant with the desired trait or traits faster than classical breeding because the majority of the plant's genome is not altered. To genetically modify a plant, a genetic construct must be designed so that the gene to be added or removed will be expressed by the plant. To do this, a promoter to drive transcription and a termination sequence to stop transcription of the new gene, and the gene or genes of interest must be introduced to the plant. A marker for the selection of transformed plants is also included. In the laboratory, antibiotic resistance is a commonly used marker: Plants that have been successfully transformed will grow on media containing antibiotics; plants that have not been transformed will die. In some instances markers for selection are removed by backcrossing with the parent plant prior to commercial release | https://en.wikipedia.org/wiki?curid=30876044 |
Plant breeding The construct can be inserted in the plant genome by genetic recombination using the bacteria "Agrobacterium tumefaciens" or "A. rhizogenes", or by direct methods like the gene gun or microinjection. Using plant viruses to insert genetic constructs into plants is also a possibility, but the technique is limited by the host range of the virus. For example, Cauliflower mosaic virus (CaMV) only infects cauliflower and related species. Another limitation of viral vectors is that the virus is not usually passed on the progeny, so every plant has to be inoculated. The majority of commercially released transgenic plants are currently limited to plants that have introduced resistance to insect pests and herbicides. Insect resistance is achieved through incorporation of a gene from "Bacillus thuringiensis" (Bt) that encodes a protein that is toxic to some insects. For example, the cotton bollworm, a common cotton pest, feeds on Bt cotton it will ingest the toxin and die. Herbicides usually work by binding to certain plant enzymes and inhibiting their action. The enzymes that the herbicide inhibits are known as the herbicides "target site". Herbicide resistance can be engineered into crops by expressing a version of "target site" protein that is not inhibited by the herbicide. This is the method used to produce glyphosate resistant crop plants (See Glyphosate) Genetic modification can further increase yields by increasing stress tolerance to a given environment | https://en.wikipedia.org/wiki?curid=30876044 |
Plant breeding Stresses such as temperature variation, are signalled to the plant via a cascade of signalling molecules which will activate a Transcription factor to regulate Gene expression. Overexpression of particular genes involved in cold acclimation has been shown to become more resistant to freezing, which is one common cause of yield loss Genetic modification of plants that can produce pharmaceuticals (and industrial chemicals), sometimes called "pharming", is a rather radical new area of plant breeding. Modern plant breeding, whether classical or through genetic engineering, comes with issues of concern, particularly with regard to food crops. The question of whether breeding can have a negative effect on nutritional value is central in this respect. Although relatively little direct research in this area has been done, there are scientific indications that, by favoring certain aspects of a plant's development, other aspects may be retarded. A study published in the "Journal of the American College of Nutrition" in 2004, entitled "Changes in USDA Food Composition Data for 43 Garden Crops, 1950 to 1999", compared nutritional analysis of vegetables done in 1950 and in 1999, and found substantial decreases in six of 13 nutrients measured, including 6% of protein and 38% of riboflavin. Reductions in calcium, phosphorus, iron and ascorbic acid were also found | https://en.wikipedia.org/wiki?curid=30876044 |
Plant breeding The study, conducted at the Biochemical Institute, University of Texas at Austin, concluded in summary: ""We suggest that any real declines are generally most easily explained by changes in cultivated varieties between 1950 and 1999, in which there may be trade-offs between yield and nutrient content."" The debate surrounding genetically modified food during the 1990s peaked in 1999 in terms of media coverage and risk perception, and continues today – for example, ""Germany has thrown its weight behind a growing European mutiny over genetically modified crops by banning the planting of a widely grown pest-resistant corn variety."" The debate encompasses the ecological impact of genetically modified plants, the safety of genetically modified food and concepts used for safety evaluation like substantial equivalence. Such concerns are not new to plant breeding. Most countries have regulatory processes in place to help ensure that new crop varieties entering the marketplace are both safe and meet farmers' needs. Examples include variety registration, seed schemes, regulatory authorizations for GM plants, etc. Plant breeders' rights is also a major and controversial issue. Today, production of new varieties is dominated by commercial plant breeders, who seek to protect their work and collect royalties through national and international agreements based in intellectual property rights. The range of related issues is complex | https://en.wikipedia.org/wiki?curid=30876044 |
Plant breeding In the simplest terms, critics of the increasingly restrictive regulations argue that, through a combination of technical and economic pressures, commercial breeders are reducing biodiversity and significantly constraining individuals (such as farmers) from developing and trading seed on a regional level. Efforts to strengthen breeders' rights, for example, by lengthening periods of variety protection, are ongoing. When new plant breeds or cultivars are bred, they must be maintained and propagated. Some plants are propagated by asexual means while others are propagated by seeds. Seed propagated cultivars require specific control over seed source and production procedures to maintain the integrity of the plant breeds results. Isolation is necessary to prevent cross contamination with related plants or the mixing of seeds after harvesting. Isolation is normally accomplished by planting distance but in certain crops, plants are enclosed in greenhouses or cages (most commonly used when producing F1 hybrids.) Critics of organic agriculture claim it is too low-yielding to be a viable alternative to conventional agriculture. However, part of that poor performance may be the result of growing poorly adapted varieties. It is estimated that over 95% of organic agriculture is based on conventionally adapted varieties, even though the production environments found in organic vs. conventional farming systems are vastly different due to their distinctive management practices | https://en.wikipedia.org/wiki?curid=30876044 |
Plant breeding Most notably, organic farmers have fewer inputs available than conventional growers to control their production environments. Breeding varieties specifically adapted to the unique conditions of organic agriculture is critical for this sector to realize its full potential. This requires selection for traits such as: Currently, few breeding programs are directed at organic agriculture and until recently those that did address this sector have generally relied on indirect selection (i.e. selection in conventional environments for traits considered important for organic agriculture). However, because the difference between organic and conventional environments is large, a given genotype may perform very differently in each environment due to an interaction between genes and the environment (see gene-environment interaction). If this interaction is severe enough, an important trait required for the organic environment may not be revealed in the conventional environment, which can result in the selection of poorly adapted individuals. To ensure the most adapted varieties are identified, advocates of organic breeding now promote the use of direct selection (i.e. selection in the target environment) for many agronomic traits. There are many classical and modern breeding techniques that can be utilized for crop improvement in organic agriculture despite the ban on genetically modified organisms | https://en.wikipedia.org/wiki?curid=30876044 |
Plant breeding For instance, controlled crosses between individuals allow desirable genetic variation to be recombined and transferred to seed progeny via natural processes. Marker assisted selection can also be employed as a diagnostics tool to facilitate selection of progeny who possess the desired trait(s), greatly speeding up the breeding process. This technique has proven particularly useful for the introgression of resistance genes into new backgrounds, as well as the efficient selection of many resistance genes pyramided into a single individual. Unfortunately, molecular markers are not currently available for many important traits, especially complex ones controlled by many genes. For agriculture to thrive in the future, changes must be made to address arising global issues. These issues are the lack of arable land, increasingly harsh cropping conditions and the need to maintain food security, which involves being able to provide the world population with sufficient nutrition. Crops need to be able to mature in multiple environments to allow worldwide access, which involves solving problems including drought tolerance. It has been suggested that global solutions are achievable through the process of plant breeding, with its ability to select specific genes allowing crops to perform at a level which yields the desired results. With an increasing population, the production of food needs to increase with it | https://en.wikipedia.org/wiki?curid=30876044 |
Plant breeding It is estimated that a 70% increase in food production is needed by 2050 in order to meet the Declaration of the World Summit on Food Security. But with the degradation of agricultural land, simply planting more crops is no longer a viable option. New varieties of plants can in some cases be developed through plant breeding that generate an increase of yield without relying on an increase in land area. An example of this can be seen in Asia, where food production per capita has increased twofold. This has been achieved through not only the use of fertilisers, but through the use of better crops that have been specifically designed for the area. can contribute to global food security as it is a cost-effective tool for increasing nutritional value of forage and crops. Improvements in nutritional value for forage crops from the use of analytical chemistry and rumen fermentation technology have been recorded since 1960; this science and technology gave breeders the ability to screen thousands of samples within a small amount of time, meaning breeders could identify a high performing hybrid quicker. The main area genetic increases were made was in vitro dry matter digestibility (IVDMD) resulting in 0.7-2.5% increase, at just 1% increase in IVDMD a single Bos Taurus also known as beef cattle reported 3.2% increase in daily gains. This improvement indicates plant breeding is an essential tool in gearing future agriculture to perform at a more advanced level | https://en.wikipedia.org/wiki?curid=30876044 |
Plant breeding of hybrid crops has become extremely popular worldwide in an effort to combat the harsh environment. With long periods of drought and lack of water or nitrogen stress tolerance has become a significant part of agriculture. Plant breeders have focused on identifying crops which will ensure crops perform under these conditions; a way to achieve this is finding strains of the crop that is resistance to drought conditions with low nitrogen. It is evident from this that plant breeding is vital for future agriculture to survive as it enables farmers to produce stress resistant crops hence improving food security. In countries that experience harsh winters such as Iceland, Germany and further east in Europe, plant breeders are involved in breeding for tolerance to frost, continuous snow-cover, frost-drought (desiccation from wind and solar radiation under frost) and high moisture levels in soil in winter. Participatory plant breeding (PPB) is when farmers are involved in a crop improvement programme with opportunities to make decisions and contribute to the research process at different stages. Participatory approaches to crop improvement can also be applied when plant biotechnologies are being used for crop improvement. Local agricultural systems and genetic diversity are developed and strengthened by crop improvement, which participatory crop improvement (PCI) plays a large role. PPB is enhanced by farmers knowledge of the quality required and evaluation of target environment which affects the effectiveness of PPB. | https://en.wikipedia.org/wiki?curid=30876044 |
Unburned hydrocarbon Unburnt hydrocarbons (UHCs) are the hydrocarbons emitted after petroleum is burned in an engine. When unburnt fuel is emitted from a combustor, the emission is caused by fuel "avoiding" the flame zones. For example, in piston engines, some of the fuel-air mixture "hides" from the flame in the crevices provided by the piston ring grooves. Further, some regions of the combustion chamber may have a very weak flame, that is, they have either very fuel-lean or very fuel-rich conditions and consequently they have a low combustion temperature. These regions will cause intermediate species such as formaldehyde and alkenes to be emitted. Sometimes the term "products of incomplete combustion," or PICs, is used to describe such species. The hydrocarbon is a auspicious way to reach low NOx (nitrogen oxide) emissions in diesel engines but one of its disadvantages is drastic increasing amount of unburned hydrocarbons.<ref> | https://en.wikipedia.org/wiki?curid=30876715 |
Molecular cloning is a set of experimental methods in molecular biology that are used to assemble recombinant DNA molecules and to direct their replication within host organisms. The use of the word "cloning" refers to the fact that the method involves the replication of one molecule to produce a population of cells with identical DNA molecules. generally uses DNA sequences from two different organisms: the species that is the source of the DNA to be cloned, and the species that will serve as the living host for replication of the recombinant DNA. methods are central to many contemporary areas of modern biology and medicine. In a conventional molecular cloning experiment, the DNA to be cloned is obtained from an organism of interest, then treated with enzymes in the test tube to generate smaller DNA fragments. Subsequently, these fragments are then combined with vector DNA to generate recombinant DNA molecules. The recombinant DNA is then introduced into a host organism (typically an easy-to-grow, benign, laboratory strain of "E. coli" bacteria). This will generate a population of organisms in which recombinant DNA molecules are replicated along with the host DNA. Because they contain foreign DNA fragments, these are transgenic or genetically modified microorganisms (GMO). This process takes advantage of the fact that a single bacterial cell can be induced to take up and replicate a single recombinant DNA molecule | https://en.wikipedia.org/wiki?curid=30876867 |
Molecular cloning This single cell can then be expanded exponentially to generate a large amount of bacteria, each of which contain copies of the original recombinant molecule. Thus, both the resulting bacterial population, and the recombinant DNA molecule, are commonly referred to as "clones". Strictly speaking, "recombinant DNA" refers to DNA molecules, while "molecular cloning" refers to the experimental methods used to assemble them. The idea arose that different DNA sequences could be inserted into a plasmid and that these foreign sequences would be carried into bacteria and digested as part of the plasmid. That is, these plasmids could serve as cloning vectors to carry genes. Virtually any DNA sequence can be cloned and amplified, but there are some factors that might limit the success of the process. Examples of the DNA sequences that are difficult to clone are inverted repeats, origins of replication, centromeres and telomeres. Another characteristic that limits chances of success is large size of DNA sequence. Inserts larger than 10kbp have very limited success, but bacteriophages such as bacteriophage λ can be modified to successfully insert a sequence up to 40 kbp. Prior to the 1970s, the understanding of genetics and molecular biology was severely hampered by an inability to isolate and study individual genes from complex organisms. This changed dramatically with the advent of molecular cloning methods | https://en.wikipedia.org/wiki?curid=30876867 |
Molecular cloning Microbiologists, seeking to understand the molecular mechanisms through which bacteria restricted the growth of bacteriophage, isolated restriction endonucleases, enzymes that could cleave DNA molecules only when specific DNA sequences were encountered. They showed that restriction enzymes cleaved chromosome-length DNA molecules at specific locations, and that specific sections of the larger molecule could be purified by size fractionation. Using a second enzyme, DNA ligase, fragments generated by restriction enzymes could be joined in new combinations, termed recombinant DNA. By recombining DNA segments of interest with vector DNA, such as bacteriophage or plasmids, which naturally replicate inside bacteria, large quantities of purified recombinant DNA molecules could be produced in bacterial cultures. The first recombinant DNA molecules were generated and studied in 1972. takes advantage of the fact that the chemical structure of DNA is fundamentally the same in all living organisms. Therefore, if any segment of DNA from any organism is inserted into a DNA segment containing the molecular sequences required for DNA replication, and the resulting recombinant DNA is introduced into the organism from which the replication sequences were obtained, then the foreign DNA will be replicated along with the host cell's DNA in the transgenic organism. is similar to polymerase chain reaction (PCR) in that it permits the replication of DNA sequence | https://en.wikipedia.org/wiki?curid=30876867 |
Molecular cloning The fundamental difference between the two methods is that molecular cloning involves replication of the DNA in a living microorganism, while PCR replicates DNA in an "in vitro" solution, free of living cells. In standard molecular cloning experiments, the cloning of any DNA fragment essentially involves seven steps: (1) Choice of host organism and cloning vector, (2) Preparation of vector DNA, (3) Preparation of DNA to be cloned, (4) Creation of recombinant DNA, (5) Introduction of recombinant DNA into host organism, (6) Selection of organisms containing recombinant DNA, (7) Screening for clones with desired DNA inserts and biological properties. Although the detailed planning of the cloning can be done in any text editor, together with online utilities for e.g. PCR primer design, dedicated software exist for the purpose. Software for the purpose include for example ApE (open source), DNAStrider (open source), Serial Cloner (gratis) and Collagene (open source). Notably, the growing capacity and fidelity of DNA synthesis platforms allows for increasingly intricate designs in molecular engineering. These projects may include very long strands of novel DNA sequence and/or test entire libraries simultaneously, as opposed to of individual sequences. These shifts introduce complexity that require design to move away from the flat nucleotide-based representation and towards a higher level of abstraction. Examples of such tools are GenoCAD, Teselagen (free for academia) or GeneticConstructor (free for academics) | https://en.wikipedia.org/wiki?curid=30876867 |
Molecular cloning Although a very large number of host organisms and molecular cloning vectors are in use, the great majority of molecular cloning experiments begin with a laboratory strain of the bacterium "E. coli" ("Escherichia coli") and a plasmid cloning vector. "E. coli" and plasmid vectors are in common use because they are technically sophisticated, versatile, widely available, and offer rapid growth of recombinant organisms with minimal equipment. If the DNA to be cloned is exceptionally large (hundreds of thousands to millions of base pairs), then a bacterial artificial chromosome or yeast artificial chromosome vector is often chosen. Specialized applications may call for specialized host-vector systems. For example, if the experimentalists wish to harvest a particular protein from the recombinant organism, then an expression vector is chosen that contains appropriate signals for transcription and translation in the desired host organism. Alternatively, if replication of the DNA in different species is desired (for example, transfer of DNA from bacteria to plants), then a multiple host range vector (also termed shuttle vector) may be selected. In practice, however, specialized molecular cloning experiments usually begin with cloning into a bacterial plasmid, followed by subcloning into a specialized vector | https://en.wikipedia.org/wiki?curid=30876867 |
Molecular cloning Whatever combination of host and vector are used, the vector almost always contains four DNA segments that are critically important to its function and experimental utility: The cloning vector is treated with a restriction endonuclease to cleave the DNA at the site where foreign DNA will be inserted. The restriction enzyme is chosen to generate a configuration at the cleavage site that is compatible with the ends of the foreign DNA (see DNA end). Typically, this is done by cleaving the vector DNA and foreign DNA with the same restriction enzyme, for example EcoRI. Most modern vectors contain a variety of convenient cleavage sites that are unique within the vector molecule (so that the vector can only be cleaved at a single site) and are located within a gene (frequently beta-galactosidase) whose inactivation can be used to distinguish recombinant from non-recombinant organisms at a later step in the process. To improve the ratio of recombinant to non-recombinant organisms, the cleaved vector may be treated with an enzyme (alkaline phosphatase) that dephosphorylates the vector ends. Vector molecules with dephosphorylated ends are unable to replicate, and replication can only be restored if foreign DNA is integrated into the cleavage site. For cloning of genomic DNA, the DNA to be cloned is extracted from the organism of interest. Virtually any tissue source can be used (even tissues from extinct animals), as long as the DNA is not extensively degraded | https://en.wikipedia.org/wiki?curid=30876867 |
Molecular cloning The DNA is then purified using simple methods to remove contaminating proteins (extraction with phenol), RNA (ribonuclease) and smaller molecules (precipitation and/or chromatography). Polymerase chain reaction (PCR) methods are often used for amplification of specific DNA or RNA (RT-PCR) sequences prior to molecular cloning. DNA for cloning experiments may also be obtained from RNA using reverse transcriptase (complementary DNA or cDNA cloning), or in the form of synthetic DNA (artificial gene synthesis). cDNA cloning is usually used to obtain clones representative of the mRNA population of the cells of interest, while synthetic DNA is used to obtain any precise sequence defined by the designer. Such a designed sequence may be required when moving genes across genetic codes (for example, from the mitochrondria to the nucleus) or simply for increasing expression via codon optimization. The purified DNA is then treated with a restriction enzyme to generate fragments with ends capable of being linked to those of the vector. If necessary, short double-stranded segments of DNA ("linkers") containing desired restriction sites may be added to create end structures that are compatible with the vector. The creation of recombinant DNA is in many ways the simplest step of the molecular cloning process. DNA prepared from the vector and foreign source are simply mixed together at appropriate concentrations and exposed to an enzyme (DNA ligase) that covalently links the ends together | https://en.wikipedia.org/wiki?curid=30876867 |
Molecular cloning This joining reaction is often termed ligation. The resulting DNA mixture containing randomly joined ends is then ready for introduction into the host organism. DNA ligase only recognizes and acts on the ends of linear DNA molecules, usually resulting in a complex mixture of DNA molecules with randomly joined ends. The desired products (vector DNA covalently linked to foreign DNA) will be present, but other sequences (e.g. foreign DNA linked to itself, vector DNA linked to itself and higher-order combinations of vector and foreign DNA) are also usually present. This complex mixture is sorted out in subsequent steps of the cloning process, after the DNA mixture is introduced into cells. The DNA mixture, previously manipulated in vitro, is moved back into a living cell, referred to as the host organism. The methods used to get DNA into cells are varied, and the name applied to this step in the molecular cloning process will often depend upon the experimental method that is chosen (e.g. transformation, transduction, transfection, electroporation). When microorganisms are able to take up and replicate DNA from their local environment, the process is termed transformation, and cells that are in a physiological state such that they can take up DNA are said to be competent. In mammalian cell culture, the analogous process of introducing DNA into cells is commonly termed transfection | https://en.wikipedia.org/wiki?curid=30876867 |
Molecular cloning Both transformation and transfection usually require preparation of the cells through a special growth regime and chemical treatment process that will vary with the specific species and cell types that are used. Electroporation uses high voltage electrical pulses to translocate DNA across the cell membrane (and cell wall, if present). In contrast, transduction involves the packaging of DNA into virus-derived particles, and using these virus-like particles to introduce the encapsulated DNA into the cell through a process resembling viral infection. Although electroporation and transduction are highly specialized methods, they may be the most efficient methods to move DNA into cells. Whichever method is used, the introduction of recombinant DNA into the chosen host organism is usually a low efficiency process; that is, only a small fraction of the cells will actually take up DNA. Experimental scientists deal with this issue through a step of artificial genetic selection, in which cells that have not taken up DNA are selectively killed, and only those cells that can actively replicate DNA containing the selectable marker gene encoded by the vector are able to survive. When bacterial cells are used as host organisms, the selectable marker is usually a gene that confers resistance to an antibiotic that would otherwise kill the cells, typically ampicillin. Cells harboring the plasmid will survive when exposed to the antibiotic, while those that have failed to take up plasmid sequences will die | https://en.wikipedia.org/wiki?curid=30876867 |
Molecular cloning When mammalian cells (e.g. human or mouse cells) are used, a similar strategy is used, except that the marker gene (in this case typically encoded as part of the kanMX cassette) confers resistance to the antibiotic Geneticin. Modern bacterial cloning vectors (e.g. pUC19 and later derivatives including the pGEM vectors) use the blue-white screening system to distinguish colonies (clones) of transgenic cells from those that contain the parental vector (i.e. vector DNA with no recombinant sequence inserted). In these vectors, foreign DNA is inserted into a sequence that encodes an essential part of beta-galactosidase, an enzyme whose activity results in formation of a blue-colored colony on the culture medium that is used for this work. Insertion of the foreign DNA into the beta-galactosidase coding sequence disables the function of the enzyme so that colonies containing transformed DNA remain colorless (white). Therefore, experimentalists are easily able to identify and conduct further studies on transgenic bacterial clones, while ignoring those that do not contain recombinant DNA. The total population of individual clones obtained in a molecular cloning experiment is often termed a DNA library. Libraries may be highly complex (as when cloning complete genomic DNA from an organism) or relatively simple (as when moving a previously cloned DNA fragment into a different plasmid), but it is almost always necessary to examine a number of different clones to be sure that the desired DNA construct is obtained | https://en.wikipedia.org/wiki?curid=30876867 |
Molecular cloning This may be accomplished through a very wide range of experimental methods, including the use of nucleic acid hybridizations, antibody probes, polymerase chain reaction, restriction fragment analysis and/or DNA sequencing. provides scientists with an essentially unlimited quantity of any individual DNA segments derived from any genome. This material can be used for a wide range of purposes, including those in both basic and applied biological science. A few of the more important applications are summarized here. has led directly to the elucidation of the complete DNA sequence of the genomes of a very large number of species and to an exploration of genetic diversity within individual species, work that has been done mostly by determining the DNA sequence of large numbers of randomly cloned fragments of the genome, and assembling the overlapping sequences. At the level of individual genes, molecular clones are used to generate probes that are used for examining how genes are expressed, and how that expression is related to other processes in biology, including the metabolic environment, extracellular signals, development, learning, senescence and cell death. Cloned genes can also provide tools to examine the biological function and importance of individual genes, by allowing investigators to inactivate the genes, or make more subtle mutations using regional mutagenesis or site-directed mutagenesis | https://en.wikipedia.org/wiki?curid=30876867 |
Molecular cloning Genes cloned into expression vectors for functional cloning provide a means to screen for genes on the basis of the expressed protein's function. Obtaining the molecular clone of a gene can lead to the development of organisms that produce the protein product of the cloned genes, termed a recombinant protein. In practice, it is frequently more difficult to develop an organism that produces an active form of the recombinant protein in desirable quantities than it is to clone the gene. This is because the molecular signals for gene expression are complex and variable, and because protein folding, stability and transport can be very challenging. Many useful proteins are currently available as recombinant products. These include--(1) medically useful proteins whose administration can correct a defective or poorly expressed gene (e.g. recombinant factor VIII, a blood-clotting factor deficient in some forms of hemophilia, and recombinant insulin, used to treat some forms of diabetes), (2) proteins that can be administered to assist in a life-threatening emergency (e.g. tissue plasminogen activator, used to treat strokes), (3) recombinant subunit vaccines, in which a purified protein can be used to immunize patients against infectious diseases, without exposing them to the infectious agent itself (e.g. hepatitis B vaccine), and (4) recombinant proteins as standard material for diagnostic laboratory tests | https://en.wikipedia.org/wiki?curid=30876867 |
Molecular cloning Once characterized and manipulated to provide signals for appropriate expression, cloned genes may be inserted into organisms, generating transgenic organisms, also termed genetically modified organisms (GMOs). Although most GMOs are generated for purposes of basic biological research (see for example, transgenic mouse), a number of GMOs have been developed for commercial use, ranging from animals and plants that produce pharmaceuticals or other compounds (pharming), herbicide-resistant crop plants, and fluorescent tropical fish (GloFish) for home entertainment. Gene therapy involves supplying a functional gene to cells lacking that function, with the aim of correcting a genetic disorder or acquired disease. Gene therapy can be broadly divided into two categories. The first is alteration of germ cells, that is, sperm or eggs, which results in a permanent genetic change for the whole organism and subsequent generations. This “germ line gene therapy” is considered by many to be unethical in human beings. The second type of gene therapy, “somatic cell gene therapy”, is analogous to an organ transplant. In this case, one or more specific tissues are targeted by direct treatment or by removal of the tissue, addition of the therapeutic gene or genes in the laboratory, and return of the treated cells to the patient. Clinical trials of somatic cell gene therapy began in the late 1990s, mostly for the treatment of cancers and blood, liver, and lung disorders | https://en.wikipedia.org/wiki?curid=30876867 |
Molecular cloning Despite a great deal of publicity and promises, the history of human gene therapy has been characterized by relatively limited success. The effect of introducing a gene into cells often promotes only partial and/or transient relief from the symptoms of the disease being treated. Some gene therapy trial patients have suffered adverse consequences of the treatment itself, including deaths. In some cases, the adverse effects result from disruption of essential genes within the patient's genome by insertional inactivation. In others, viral vectors used for gene therapy have been contaminated with infectious virus. Nevertheless, gene therapy is still held to be a promising future area of medicine, and is an area where there is a significant level of research and development activity. | https://en.wikipedia.org/wiki?curid=30876867 |
Thermal ionization Thermal ionization, also known as surface ionization or contact ionization, is a physical process whereby the atoms are desorbed from a hot surface, and in the process are ionized. is used to make simple ion sources, for mass spectrometry and for generating ion beams. has seen extensive use in determining atomic weights, in addition to being used in many geological/nuclear applications. The likelihood of ionization is a function of the filament temperature, the work function of the filament substrate and the ionization energy of the element. This is summarised in the Saha-Langmuir equation: where Negative ionization can also occur for elements with a large electron affinity formula_9 against a surface of low work function. One application of thermal ionization is thermal ionization mass spectrometry (TIMS). In thermal ionization mass spectrometry, a chemically purified material is placed onto a filament which is then heated to high temperatures to cause some of the material to be ionized as it is thermally desorbed (boiled off) the hot filament. Filaments are generally flat pieces of metal around 1-2mm wide, 0.1mm thick, bent into an upside-down U shape and attached to two contacts that supply a current. This method is widely used in radiometric dating, where the sample is ionized under vacuum. The ions being produced at the filament are focussed into an ion beam and then passed through a magnetic field to separate them by mass | https://en.wikipedia.org/wiki?curid=30876908 |
Thermal ionization The relative abundances of different isotopes can then be measured, yielding isotope ratios. When these isotope ratios are measured by TIMS, mass-dependent fractionation occurs as species are emitted by the hot filament. Fractionation occurs due to the excitation of the sample and therefore must be corrected for accurate measurement of the isotope ratio. There are several advantages of the TIMS method. It has a simple design, is less expensive than other mass spectrometers, and produces stable ion emissions. It requires a stable power supply, and is suitable for species with a low ionization energy, such as strontium and lead. The disadvantages of this method stem from the maximum temperature achieved in thermal ionization. The hot filament reaches a temperature of less than 2500 °C, leading to the inability to create atomic ions of species with a high ionization energy, such as osmium and tungsten. Although the TIMS method can create molecular ions instead in this case, species with high ionization energy can be analyzed more effectively with MC-ICP-MS. | https://en.wikipedia.org/wiki?curid=30876908 |
Uptake hexose phosphate The Uptake of Hexose Phosphates (Uhp) is a protein system found in bacteria. It is a type of two-component sensory transduction pathway which helps bacteria react to their environment. The uhp system is composed of UhpA, UhpB, UhpC, and UhpT. UhpB and UhpC are both transmembrane proteins which form a complex with each other. UhpA is a signal protein found in the cytoplasm. UhpT is a transporter protein which facilitates the uptake of phosphorylated hexose molecules into the cell. The Uhp system uptakes phosphorylated hexose sugars into bacteria. The system is triggered by phosphorylated hexose sugars on the outside of the cell. UhpC binds to the phosphorylated hexose, which allows the phosphorylation of UhpB on one of its cytoplasmic histidines. This facilitates the phosphorylation of an aspartate on UhpA, and the phosphorylated UhpA activates the transcription of UhpT. UhpT then facilitates the transport of the phosphorylated hexose sugars into the cell. | https://en.wikipedia.org/wiki?curid=30876940 |
Anthony Stone Anthony J. Stone is a British theoretical chemist and emeritus professor in the Department of Chemistry at the University of Cambridge. Stone studied Natural Sciences at Emmanuel College, Cambridge and obtained a Ph.D. in theoretical chemistry under H. Christopher Longuet-Higgins. In 1964 he took up a position in the Department of Chemistry at the University of Cambridge, where he remained until his retirement in 2006. He is known for the Stone–Wales defect of fullerene isomers. | https://en.wikipedia.org/wiki?curid=30880775 |
EDAS was a database of alternatively spliced human genes. It doesn't seem to exist anymore. | https://en.wikipedia.org/wiki?curid=30894361 |
Exon-intron database the Exon-Intron Database (EID) is a database of spliced mRNA sequences | https://en.wikipedia.org/wiki?curid=30894489 |
ExtraTrain is a database of regulatory DNA signals located in the extragenic regions of the prokaryotic genome. | https://en.wikipedia.org/wiki?curid=30894628 |
Magnetochemistry is concerned with the magnetic properties of chemical compounds. Magnetic properties arise from the spin and orbital angular momentum of the electrons contained in a compound. Compounds are diamagnetic when they contain no unpaired electrons. Molecular compounds that contain one or more unpaired electrons are paramagnetic. The magnitude of the paramagnetism is expressed as an effective magnetic moment, μ. For first-row transition metals the magnitude of μ is, to a first approximation, a simple function of the number of unpaired electrons, the spin-only formula. In general, spin-orbit coupling causes μ to deviate from the spin-only formula. For the heavier transition metals, lanthanides and actinides, spin-orbit coupling cannot be ignored. Exchange interaction can occur in clusters and infinite lattices, resulting in ferromagnetism, antiferromagnetism or ferrimagnetism depending on the relative orientations of the individual spins. The primary measurement in magnetochemistry is magnetic susceptibility. This measures the strength of interaction on placing the substance in a magnetic field. The volume magnetic susceptibility, represented by the symbol formula_1 is defined by the relationship where, formula_3 is the magnetization of the material (the magnetic dipole moment per unit volume), measured in amperes per meter ( SI units), and formula_4 is the magnetic field strength, also measured in amperes per meter. Susceptibility is a dimensionless quantity | https://en.wikipedia.org/wiki?curid=30897833 |
Magnetochemistry For chemical applications the molar magnetic susceptibility (χ) is the preferred quantity. It is measured in m·mol (SI) or cm·mol (CGS) and is defined as where ρ is the density in kg·m (SI) or g·cm (CGS) and "M" is molar mass in kg·mol (SI) or g·mol (CGS). A variety of methods are available for the measurement of magnetic susceptibility. When an isolated atom is placed in a magnetic field there is an interaction because each electron in the atom behaves like a magnet, that is, the electron has a magnetic moment. There are two types of interaction. When the atom is present in a chemical compound its magnetic behaviour is modified by its chemical environment. Measurement of the magnetic moment can give useful chemical information. In certain crystalline materials individual magnetic moments may be aligned with each other (magnetic moment has both magnitude and direction). This gives rise to ferromagnetism, antiferromagnetism or ferrimagnetism. These are properties of the crystal as a whole, of little bearing on chemical properties. Diamagnetism is a universal property of chemical compounds, because all chemical compounds contain electron pairs. A compound in which there are no unpaired electrons is said to be diamagnetic. The effect is weak because it depends on the magnitude of the induced magnetic moment. It depends on the number of electron pairs and the chemical nature of the atoms to which they belong | https://en.wikipedia.org/wiki?curid=30897833 |
Magnetochemistry This means that the effects are additive, and a table of "diamagnetic contributions", or Pascal's constants, can be put together. With paramagnetic compounds the observed susceptibility can be adjusted by adding to it the so-called diamagnetic correction, which is the diamagnetic susceptibility calculated with the values from the table. A metal ion with a single unpaired electron, such as Cu, in a coordination complex provides the simplest illustration of the mechanism of paramagnetism. The individual metal ions are kept far apart by the ligands, so that there is no magnetic interaction between them. The system is said to be magnetically dilute. The magnetic dipoles of the atoms point in random directions. When a magnetic field is applied, first-order Zeeman splitting occurs. Atoms with spins aligned to the field slightly outnumber the atoms with non-aligned spins. In the first-order Zeeman effect the energy difference between the two states is proportional to the applied field strength. Denoting the energy difference as Δ"E", the Boltzmann distribution gives the ratio of the two populations as formula_6, where "k" is the Boltzmann constant and "T" is the temperature in kelvins. In most cases Δ"E" is much smaller than "kT" and the exponential can be expanded as 1 – Δ"E/kT". It follows from the presence of 1/"T" in this expression that the susceptibility is inversely proportional to temperature | https://en.wikipedia.org/wiki?curid=30897833 |
Magnetochemistry This is known as the Curie law and the proportionality constant, "C", is known as the Curie constant, whose value, for molar susceptibility, is calculated as where "N" is the Avogadro constant, "g" is the Landé g-factor, and μ is the Bohr magneton. In this treatment it has been assumed that the electronic ground state is not degenerate, that the magnetic susceptibility is due only to electron spin and that only the ground state is thermally populated. While some substances obey the Curie law, others obey the Curie-Weiss law. "T" is the Curie temperature. The Curie-Weiss law will apply only when the temperature is well above the Curie temperature. At temperatures below the Curie temperature the substance may become ferromagnetic. More complicated behaviour is observed with the heavier transition elements. When the Curie law is obeyed, the product of molar susceptibility and temperature is a constant. The effective magnetic moment, μ is then defined as Where C has CGS units cm mol K, μ is Where C has SI units m mol K, μ is The quantity μ is effectively dimensionless, but is often stated as in units of Bohr magneton (μ). For substances that obey the Curie law, the effective magnetic moment is independent of temperature. For other substances μ is temperature dependent, but the dependence is small if the Curie-Weiss law holds and the Curie temperature is low. Compounds which are expected to be diamagnetic may exhibit this kind of weak paramagnetism | https://en.wikipedia.org/wiki?curid=30897833 |
Magnetochemistry It arises from a second-order Zeeman effect in which additional splitting, proportional to the square of the field strength, occurs. It is difficult to observe as the compound inevitably also interacts with the magnetic field in the diamagnetic sense. Nevertheless, data are available for the permanganate ion. It is easier to observe in compounds of the heavier elements, such as uranyl compounds. Exchange interactions occur when the substance is not magnetically dilute and there are interactions between individual magnetic centres. One of the simplest systems to exhibit the result of exchange interactions is crystalline copper(II) acetate, Cu(OAc)(HO). As the formula indicates, it contains two copper(II) ions. The Cu ions are held together by four acetate ligands, each of which binds to both copper ions. Each Cu ion has a d electronic configuration, and so should have one unpaired electron. If there were a covalent bond between the copper ions, the electrons would pair up and the compound would be diamagnetic. Instead, there is an exchange interaction in which the spins of the unpaired electrons become partially aligned to each other. In fact two states are created, one with spins parallel and the other with spins opposed. The energy difference between the two states is so small their populations vary significantly with temperature. In consequence the magnetic moment varies with temperature in a sigmoidal pattern | https://en.wikipedia.org/wiki?curid=30897833 |
Magnetochemistry The state with spins opposed has lower energy, so the interaction can be classed as antiferromagnetic in this case. It is believed that this is an example of superexchange, mediated by the oxygen and carbon atoms of the acetate ligands. Other dimers and clusters exhibit exchange behaviour. Exchange interactions can act over infinite chains in one dimension, planes in two dimensions or over a whole crystal in three dimensions. These are examples of long-range magnetic ordering. They give rise to ferromagnetism, antiferromagnetism or ferrimagnetism, depending on the nature and relative orientations of the individual spins. Compounds at temperatures below the Curie temperature exhibit long-range magnetic order in the form of ferromagnetism. Another critical temperature is the Néel temperature, below which antiferromagnetism occurs. The hexahydrate of nickel chloride, NiCl·6HO, has a Néel temperature of 8.3 K. The susceptibility is a maximum at this temperature. Below the Néel temperature the susceptibility decreases and the substance becomes antiferromagnetic. The effective magnetic moment for a compound containing a transition metal ion with one or more unpaired electrons depends on the total orbital and spin angular momentum of the unpaired electrons, formula_13 and formula_14, respectively. "Total" in this context means "vector sum" | https://en.wikipedia.org/wiki?curid=30897833 |
Magnetochemistry In the approximation that the electronic states of the metal ions are determined by Russell-Saunders coupling and that spin-orbit coupling is negligible, the magnetic moment is given by Orbital angular momentum is generated when an electron in an orbital of a degenerate set of orbitals is moved to another orbital in the set by rotation. In complexes of low symmetry certain rotations are not possible. In that case the orbital angular momentum is said to be "quenched" and formula_13 is smaller than might be expected (partial quenching), or zero (complete quenching). There is complete quenching in the following cases. Note that an electron in a degenerate pair of d or d orbitals cannot rotate into the other orbital because of symmetry. When orbital angular momentum is completely quenched, formula_17 and the paramagnetism can be attributed to electron spin alone. The total spin angular momentum is simply half the number of unpaired electrons and the spin-only formula results. where "n" is the number of unpaired electrons. The spin-only formula is a good first approximation for high-spin complexes of first-row transition metals. The small deviations from the spin-only formula may result from the neglect of orbital angular momentum or of spin-orbit coupling. For example, tetrahedral d, d, d and d complexes tend to show larger deviations from the spin-only formula than octahedral complexes of the same ion, because "quenching" of the orbital contribution is less effective in the tetrahedral case | https://en.wikipedia.org/wiki?curid=30897833 |
Magnetochemistry According to crystal field theory, the "d" orbitals of a transition metal ion in an octahedal complex are split into two groups in a crystal field. If the splitting is large enough to overcome the energy needed to place electrons in the same orbital, with opposite spin, a low-spin complex will result. With one unpaired electron μ values range from 1.8 to 2.5 μ and with two unpaired electrons the range is 3.18 to 3.3 μ. Note that low-spin complexes of Fe and Co are diamagnetic. Another group of complexes that are diamagnetic are square-planar complexes of d ions such as Ni and Rh and Au. When the energy difference between the high-spin and low-spin states is comparable to kT (k is the Boltzmann constant and T the temperature) an equilibrium is established between the spin states, involving what have been called "electronic isomers". Tris-dithiocarbamato iron(III), Fe(SCNR), is a well-documented example. The effective moment varies from a typical d low-spin value of 2.25 μ at 80 K to more than 4 μ above 300 K. Crystal field splitting is larger for complexes of the heavier transition metals than for the transition metals discussed above. A consequence of this is that low-spin complexes are much more common. Spin-orbit coupling constants, ζ, are also larger and cannot be ignored, even in elementary treatments. The magnetic behaviour has been summarized, as below, together with an extensive table of data | https://en.wikipedia.org/wiki?curid=30897833 |
Magnetochemistry Russell-Saunders coupling, LS coupling, applies to the lanthanide ions, crystal field effects can be ignored, but spin-orbit coupling is not negligible. Consequently, spin and orbital angular momenta have to be combined and the calculated magnetic moment is given by In actinides spin-orbit coupling is strong and the coupling approximates to "j" "j" coupling. This means that it is difficult to calculate the effective moment. For example, uranium(IV), f, in the complex [UCl] has a measured effective moment of 2.2 μ, which includes a contribution from temperature-independent paramagnetism. Very few compounds of main group elements are paramagnetic. Notable examples include: oxygen, O; nitric oxide, NO; nitrogen dioxide, NO and chlorine dioxide, ClO. In organic chemistry, compounds with an unpaired electron are said to be free radicals. Free radicals, with some exceptions, are short-lived because one free radical will react rapidly with another, so their magnetic properties are difficult to study. However, if the radicals are well separated from each other in a dilute solution in a solid matrix, at low temperature, they can be studied by electron paramagnetic resonance (EPR). Such radicals are generated by irradiation. Extensive EPR studies have revealed much about electron delocalization in free radicals. The simulated spectrum of the CH• radical shows hyperfine splitting due to the interaction of the electron with the 3 equivalent hydrogen nuclei, each of which has a spin of 1/2 | https://en.wikipedia.org/wiki?curid=30897833 |
Magnetochemistry Spin labels are long-lived free radicals which can be inserted into organic molecules so that they can be studied by EPR. The gadolinium ion, Gd, has the f electronic configuration, with all spins parallel. Compounds of the Gd ion are the most suitable for use as a contrast agent for MRI scans. The magnetic moments of gadolinium compounds are larger than those of any transition metal ion. Gadolinium is preferred to other lanthanide ions, some of which have larger effective moments, due to its having a non-degenerate electronic ground state. For many years the nature of oxyhemoglobin, Hb-O, was highly controversial. It was found experimentally to be diamagnetic. Deoxy-hemoglobin is generally accepted to be a complex of iron in the +2 oxidation state, that is a d system with a high-spin magnetic moment near to the spin-only value of 4.9 μ. It was proposed that the iron is oxidized and the oxygen reduced to superoxide. Pairing up of electrons from Fe and O was then proposed to occur via an exchange mechanism. It has now been shown that in fact the iron(II) changes from high-spin to low-spin when an oxygen molecule donates a pair of electrons to the iron. Whereas in deoxy-hemoglobin the iron atom lies above the plane of the heme, in the low-spin complex the effective ionic radius is reduced and the iron atom lies in the heme plane. This information has an important bearing on research to find artificial oxygen carriers. Compounds of gallium(II) were unknown until quite recently | https://en.wikipedia.org/wiki?curid=30897833 |
Magnetochemistry As the atomic number of gallium is an odd number (31), Ga should have an unpaired electron. It was assumed that it would act as a free radical and have a very short lifetime. The non-existence of Ga(II) compounds was part of the so-called inert pair effect. When salts of the anion with empirical formula such as [GaCl] were synthesized they were found to be diamagnetic. This implied the formation of a Ga-Ga bond and a dimeric formula, [GaCl]. | https://en.wikipedia.org/wiki?curid=30897833 |
Federation of Analytical Chemistry and Spectroscopy Societies The or FACSS is a scientific society incorporated on June 28, 1972 with the goal of promoting research and education in analytical chemistry. The organization combined the many smaller meetings of the individual societies into an annual meeting that includes all of analytical chemistry. The meetings are intended to provide a forum for scientists to address the development of analytical chemistry, chromatography, and spectroscopy. The society's main activity is its annual conference held every fall. These conference offer plenary sessions, workshops, job fairs, oral presentations, poster presentations, and conference networking events. The conference was held internationally for the first time in 1999 when it was hosted in Vancouver, BC. The annual conference is often discussed in the journal Applied Spectroscopy, Spectroscopy Magazine, and American Pharmaceutical Reviews. At the 2011 FACSS Conference in Reno, NV, the FACSS organization changed the name of the annual conference to SciX. The first SciX Conference presented by FACSS was held in Kansas City, MO in 2012. The name change was discussed in Spectroscopy in fall 2011: . More information about the new name can be found at scixconference.org FACSS presents several awards to both students and professionals. These awards honor scientists who have made significant contributions to the field of Analytical Chemistry. The FACSS Innovation Award was started in 2011 at the Reno meeting | https://en.wikipedia.org/wiki?curid=30903129 |
Federation of Analytical Chemistry and Spectroscopy Societies Accompanying each conference, attendees receive a final program book of abstracts which includes the schedule of talks, profiles of award winners, a list of exhibitors, and much more. Copies of these final programs for all forty of the conferences held by FACSS are available for download as .pdf files from the FACSS website, under Past Events. | https://en.wikipedia.org/wiki?curid=30903129 |
Astressin-B (AST) is a nonselective corticotropin releasing hormone antagonist that reduces the synthesis of ACTH and cortisol. Reducing ACTH synthesis, it improves the sexual drive of rats under stressing conditions. In 2011, research showed that treatment with astressin-B caused the sudden growth of hair in mice bred for a propensity for stress. | https://en.wikipedia.org/wiki?curid=30908938 |
4,4'-Thiodianiline (TDA) is an aromatic amine which is presumed to be carcinogenic to humans. TDA is not combustible, but when heated it may decompose to form irritating and toxic fumes. An analogue of TDA is dapsone. Sulfur is boiled in excess aniline over several hours to produce three isomers (1,1'; 1,4; 4,4') of TDA. The same journal documents syntheses of similar and overlapping compounds by Merz and Weith in 1871, and K. A. Hoffman in 1894. A study by Nietzki and Bothof shows indications that including an oxide of lead may maximize the yield of the 4,4' variant that this page refers to. TDA was used as a chemical intermediate in the production of three dyes: CI mordant yellow 16, milling red G and milling red FR, as well as the medicine Dapsone. TDA is no longer produced in the USA. TDA has caused mutations in some strains of "Salmonella typhimurium" and has caused tumors in laboratory mice and rats. | https://en.wikipedia.org/wiki?curid=30911813 |
C9H8N2O2 The molecular formula CHNO may refer to: | https://en.wikipedia.org/wiki?curid=30917217 |
C8H7N3O5 The molecular formula CHNO may refer to: | https://en.wikipedia.org/wiki?curid=30917280 |
Weld-On is a division of IPS Corporation, a manufacturer of solvent cements, primers, and cleaners for PVC, CPVC, and ABS plastic piping systems. products are commonly used for joining plastic pipes and fittings. also manufactures specialty products from repair adhesives for leaking pipes, pipe thread sealants / joint compounds, to test plugs for pipeline pressure testing. Their products are most commonly utilized in the irrigation, industrial, pool & spa, electrical conduit, and plumbing industries. Headquartered in California, has operations throughout the United States, as well as in China, and a worldwide network of sales representatives and distributors. | https://en.wikipedia.org/wiki?curid=30923636 |
Chemfluence (Consortium of Chemical Technologists) is the National level technical symposium of Department of Chemical Engineering, A C College of Technology, Anna University. Started in 1994 as a college level symposium, it is now in its 24th year of technical excellence. Paper presentations, poster presentations, guest lectures, workshops and events form an integral part of the Symposium. The symposium mainly aims at nourishing budding Chemical engineers with knowledge of core concepts and providing an opportunity to showcase their talents. With more that 20 events across 5 days, it is one of the most prestigious tech events of South India. It is also one of the very few symposiums in India to host a cultural fest in association with the University Departments. is conducted annually by Consortium of Chemical Technologists (CCT), the official student body of Department of Chemical Engineering, Anna University. Chemfluence, is a national level technical symposium ( Technical and Cultural Events ) organized annually by the Department of Chemical Engineering, A.C.Tech, Anna University every year since 1994. With an array of events spread across three days it seeks to provide a platform for dextrous Chemical Engineers across the nation to show off their technical powers and develop their full intellectual potential. With innovation as inspiration and technical knowledge as a tool, aims at bringing a complete transformation to the very grassroots of the field | https://en.wikipedia.org/wiki?curid=30928917 |
Chemfluence gives an opportunity for engineering students to look beyond their course and curriculum, to roll back their sleeves, with the technical wand in their hands and do some real magic. was started in the year 1994 by the students of The Department of Chemical Engineering, A.C.Tech, Anna University. Since then had been a massive success and been attracting more participants and has become a phenomenal hit among the events by other Chemical Engineers around the country. for the academic year 2012-2013 was conducted by Department of Chemical Engineering, from 27 February 2013 to Friday, 1 March 2013. Some of the major events conducted this year have been 2014 was a six-day technical extravaganza organised by the students of Department of Chemical Engineering from 25 February 2014 to 3 March 2014 under the theme of Energy and Environment. Several Workshops and Guest lectures were conducted to impart practical and technical knowledge to the budding Engineers. A National Conference on Energy and Environment, EECON'14 was conducted as a part of Chemfluence'14 3 March 2014. Acknowledging the mindset of budding engineers to assimilate concepts in a practical way, Chemfluence'14 gave several Workshops like As part of Chemfluence'14, the final day of the symposium was reserved for EECON'14 - the first National Conference on Energy & Environment. Being the first ever symposium to be organised in the University by the student fraternity, the conference begun with the EECON'14 souvenir release and a keynote address by Dr. G | https://en.wikipedia.org/wiki?curid=30928917 |
Chemfluence Sekaran, Chief Scientist, CLRI on handling wastes in the tanning sector at the Colin Mckenzie Auditorium. Subsequently, six paper presentation sessions and a poster presentation session were held on a plethora of topics such as Solid Waste Management, Air Pollution Control and Modeling of Environmentally benign processes. Chairpersons for the sessions were personalities high on caliber including Dr. T. Renganathan, Assistant Professor, IIT- Madras, Dr. S. Kanmani, Director, CTDT, Anna University and Dr. M. K. Gowthaman, CLRI amongst many others. for the academic year 2015-2016 was held from 18 March 2016 to 22 March 2016 based on the theme of Waste Management. GMW 2k16, A national conference on Global Management of Waste will be conducted by the organizing committee consisting of the Students and Faculties of Department of Chemical Engineering. Today’s industries are in need of innovative ideas and cost cutting techniques to increase the demands for their products in the highly competitive global market with fast depleting resources. Waste management is one of the most serious concerns in industries which needs to be tackled with highly efficient and out-of-the-box ideas that revamp the whole scenario, thus in a way, Transforming Waste into Wealth. With this in concern, ’16 has a theme of Waste Management. This year CCT has planned to conduct GMW 2k16 is the national conference on Global Management of Waste 2016 | https://en.wikipedia.org/wiki?curid=30928917 |
Chemfluence It is a nationwide congregation of engineering graduates,Research scholars and Professionals to deal with Waste Management. The aim of the conference is to generate new perspectives on ways to handle waste. Waste generation is a pressing issue. In India, 94% of waste is being dumped on land. Waste includes Municipal, Agricultural, Industrial, Electronic, Fuel Waste and Land waste. Energy can also be generated from waste. Though methods such as conversion of waste water to ethanol and Vermicomposting are available, a large scale, cost effective and feasible solution is very much required. And this is exactly what we hope to achieve through GMW 2k16. GMW 2k16 will provide a unique stage for establishing new waste management related technologies that would Reform Refuse to Riches. This year, for the first time in India, video presentation will be conducted instead of the usual Poster Presentation. It is a common occurrence in International Conferences and GMW 2k16 will follow the suit. | https://en.wikipedia.org/wiki?curid=30928917 |
Chemical Science (journal) Chemical Science is a weekly peer-reviewed scientific journal covering all aspects of chemistry. It was established in July 2010 and is published by the Royal Society of Chemistry; before 2018, it was published monthly. It won the Best New Journal 2011 award from the Association of Learned and Professional Society Publishers. The editor-in-chief is Andrew Ian Cooper (University of Liverpool). In January 2015, the journal moved to an open access publishing model. The journal is abstracted and indexed in: According to the "Journal Citation Reports", the journal has a 2018 impact factor of 9.556. | https://en.wikipedia.org/wiki?curid=30929442 |
Anthraquinone process The anthraquinone process is a process for the production of hydrogen peroxide, which was developed by BASF. The industrial production of hydrogen peroxide is based on the reduction of oxygen, as in the direct synthesis from the elements. Instead of hydrogen itself, however, a 2-alkyl-anthrahydroquinone, which is generated before from the corresponding 2-alkyl-anthraquinone by catalytic hydrogenation with palladium. Oxygen and the organic phase react under formation of the anthraquinone and hydrogen peroxide. Among other alkyl groups (R) ethyl- and tert. Butyl are used, e.g., 2-ethylanthraquinone. The hydrogen peroxide is then extracted with water and in a second step separated by fractional distillation from the water. The hydrogen peroxide accumulates as sump product. The anthraquinone acts as a catalyst, the overall reaction equation is therefore: If ozone is used instead of oxygen, dihydrogen trioxide can be produced by this method. | https://en.wikipedia.org/wiki?curid=30932321 |
List of compounds with carbon number 12 This is a partial list of molecules that contain 12 carbon atoms. | https://en.wikipedia.org/wiki?curid=30935057 |
Short-path distillation is a distillation technique that involves the distillate travelling a short distance, often only a few centimeters, and is normally done at reduced pressure. A classic example would be a distillation involving the distillate travelling from one glass bulb to another, without the need for a condenser separating the two chambers. This technique is often used for compounds which are unstable at high temperatures or to purify small amounts of compound. The advantage is that the heating temperature can be considerably lower (at reduced pressure) than the boiling point of the liquid at standard pressure, and the distillate only has to travel a short distance before condensing. A short path ensures that little compound is lost on the sides of the apparatus. The Kugelrohr is a kind of a short path distillation apparatus which often contain multiple chambers to collect distillate fractions. | https://en.wikipedia.org/wiki?curid=30942109 |
Thermoporometry and cryoporometry are methods for measuring porosity and pore-size distributions. A small region of solid melts at a lower temperature than the bulk solid, as given by the Gibbs–Thomson equation. Thus, if a liquid is imbibed into a porous material, and then frozen, the melting temperature will provide information on the pore-size distribution. The detection of the melting can be done by sensing the transient heat flows during phase transitions using differential scanning calorimetry – DSC thermoporometry, measuring the quantity of mobile liquid using nuclear magnetic resonance – NMR cryoporometry (NMRC) or measuring the amplitude of neutron scattering from the imbibed crystalline or liquid phases – ND cryoporometry (NDC). To make a thermoporometry / cryoporometry measurement, a liquid is imbibed into the porous sample, the sample cooled until all the liquid is frozen, and then warmed until all the liquid is again melted. Measurements are made of the phase changes or of the quantity of the liquid that is crystalline / liquid (depending on the measurement technique used). The techniques make use of the Gibbs–Thomson effect: small crystals of a liquid in the pores melt at a lower temperature than the bulk liquid : The melting point depression is inversely proportional to the pore size. The technique is closely related to that of use of gas adsorption to measure pore sizes but uses the Gibbs–Thomson equation rather than the Kelvin equation | https://en.wikipedia.org/wiki?curid=30950746 |
Thermoporometry and cryoporometry They are both particular cases of the Gibbs Equations (Josiah Willard Gibbs): the Kelvin equation is the constant temperature case, and the Gibbs–Thomson equation is the constant pressure case. This technique uses differential scanning calorimetry (DSC) to detect the phase changes. The signal detection relies on transient heat flows of latent heat of fusion at the phase changes, and thus the measurement can not be made arbitrarily slowly, limiting the resolution in pore size. There are also difficulties in obtaining measurements of pore volume. NMRC is a recent technique (originated in 1993) for measuring total porosity and pore size distributions. It makes use of the Gibbs–Thomson effect: small crystals of a liquid in the pores melt at a lower temperature than the bulk liquid : The melting point depression is inversely proportional to the pore size. The technique is closely related to that of use of gas adsorption to measure pore sizes but uses the Gibbs–Thomson equation rather than the Kelvin equation. They are both particular cases of the Gibbs Equations (Josiah Willard Gibbs): the Kelvin equation is the constant temperature case, and the Gibbs–Thomson equation is the constant pressure case. Nuclear magnetic resonance (NMR) may be used as a convenient method of measuring the quantity of liquid that has melted, as a function of temperature, making use of the fact that the formula_1 relaxation time in a frozen material is usually much shorter than that in a mobile liquid | https://en.wikipedia.org/wiki?curid=30950746 |
Thermoporometry and cryoporometry To make the measurement it is common to just measure the amplitude of an NMR echo at a few milliseconds delay, to ensure that all the signal from the solid has decayed. The technique was developed at the University of Kent in the UK, by Prof. John H. Strange. NMRC is based on two equations, the Gibbs–Thomson equation, that maps the melting point depression to pore size, and the Strange–Rahman–Smith equation that maps the melted signal amplitude at a particular temperature to pore volume. To make an NMR cryoporometry measurement, a liquid is imbibed into the porous sample, the sample cooled until all the liquid is frozen, and then warmed slowly, while measuring the quantity of the liquid that is liquid. Thus NMRC cryoporometry is similar to DSC thermoporosimetry, but has higher resolution, as the signal detection does not rely on transient heat flows, and the measurement can be made arbitrarily slowly. Volume calibration of the total porosity and pore-size can be good, just involving ratioing the NMR signal amplitude at a particular pore diameter to the amplitude when all the liquid (of known mass) is melted. NMRC is suitable for measuring pore diameters in the range 1 nm to about 10 µm. Note: the Gibbs-Thomson equation contains a geometric term relating to the curvature of the ice-liquid interface. This curvature may be different in different pore geometries; thus using a sol-gel calibration (~spheres) gives about a factor of two error when used with SBA-15 (cylindrical pores) | https://en.wikipedia.org/wiki?curid=30950746 |
Thermoporometry and cryoporometry Similarly the freezing and melting curvatures (typically spherical on ice intrusion, and cylindrical on ice melting), result in a difference in freezing and melting temperature even in cylindrical pores where there is no "ink-bottle" effect. It is also possible to adapt the basic NMRC experiment to provide structural resolution in spatially dependent pore size distributions, by combining NMRC with standard Magnetic resonance imaging protocols, or to provide behavioural information about the confined liquid. Modern neutron diffractometers have the capability to measure complete scattering spectra in a couple of minutes, as the temperature is ramped, enabling cryoporometry experiments to be performed. ND cryoporometry has the unique distinction of being able to monitor as a function of temperature the quantity of different crystalline phases (such as hexagonal ice and cubic ice) as well as the liquid phase, and thus can give pore-phase structural information as a function of temperature. The Gibbs–Thomson effect acts to lower both melting and freezing point, and also to raise boiling point. However, simple cooling of an all-liquid sample usually leads to a state of non-equilibrium super cooling and only eventual non-equilibrium freezing – to obtain a measurement of the equilibrium freezing event, it is necessary to first cool enough to freeze a sample with excess liquid outside the pores, then warm the sample until the liquid in the pores is all melted, but the bulk material is still frozen | https://en.wikipedia.org/wiki?curid=30950746 |
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