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Dimethylaminobenzaldehyde
''para''-Dimethylaminobenzaldehyde is an organic compound containing amine and aldehyde moieties which is used in Ehrlich's reagent and Kovac's reagent to test for indoles. The carbonyl group typically reacts with the electron rich 2-position of the indole but may also react at the C-3 or N-1 positions. It may also be used for determination of hydrazine. Ehrlich's reagent ''para''-Dimethylaminobenzaldehyde is the main ingredient in Ehrlich's reagent. It acts as a strong electrophile which reacts with the electron-rich α-carbon (2-position) of indole rings to form a blue-colored adduct. It can be used to detect the presence of indole alkaloids. Not all indole alkaloids give a colored adduct as result of steric hindrance which does not allow the reaction to proceed. Ehrlich's reagent is also used as a stain in thin layer chromatography and as a reagent to detect urobilinogen in fresh, cool urine. If a urine sample is left to oxidize in air to form urobilin the reagent wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ehrlich's Reagent
Ehrlich's reagent or Ehrlich reagent is a reagent containing ''p''-dimethylaminobenzaldehyde (DMAB) and thus can act as an indicator to presumptively identify indoles and urobilinogen. Several Ehrlich tests use the reagent in a medical test; some are drug tests and others contribute to diagnosis of various diseases or adverse drug reactions. It is named after Nobel Prize winner Paul Ehrlich who used it to distinguish typhoid from simple diarrhoea. The Ehrlich reagent works by binding to the C2 position of two indole moieties to form a resonance stabilised carbenium ion compound. Medical testing Ehrlich reagent can be used to detect urobilinogen, which can indicate jaundice or other liver-related issues. A very common Ehrlich test is a simple spot test to identify possible psychoactive compounds such as tryptamines (e.g. DMT) and ergoloids (e.g. LSD). It gives a negative test-result for 25I-NBOMe and many other non-indole-related psychoactives. The reagent will also give a pos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kovac's Reagent
Kovac's reagent is a biochemical reagent consisting of isoamyl alcohol, para-dimethylaminobenzaldehyde (DMAB), and concentrated hydrochloric acid. It is used for the diagnostical indole test, to determine the ability of the organism to split indole from the amino acid tryptophan. The indole produced yields a red complex with para-dimethylaminobenzaldehyde under the given conditions. This was invented by the Hungarian physician Nicholas Kovacs and was published in 1928. This reagent is used in the confirmation of ''E. coli'' and many other pathogenic microorganisms. See also Ehrlich's reagent is similar but uses ethyl alcohol Ethanol (abbr. EtOH; also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound. It is an alcohol with the chemical formula . Its formula can be also written as or (an ethyl group linked to a hyd ... or 1-propyl alcohol. References 2. Kovacs, N. (1928): Eine vereinfachte Methode zum Nachweis der Indolbil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amine
In chemistry, amines (, ) are compounds and functional groups that contain a basic nitrogen atom with a lone pair. Amines are formally derivatives of ammonia (), wherein one or more hydrogen atoms have been replaced by a substituent such as an alkyl or aryl group (these may respectively be called alkylamines and arylamines; amines in which both types of substituent are attached to one nitrogen atom may be called alkylarylamines). Important amines include amino acids, biogenic amines, trimethylamine, and aniline; Inorganic derivatives of ammonia are also called amines, such as monochloramine (). The substituent is called an amino group. Compounds with a nitrogen atom attached to a carbonyl group, thus having the structure , are called amides and have different chemical properties from amines. Classification of amines Amines can be classified according to the nature and number of substituents on nitrogen. Aliphatic amines contain only H and alkyl substituents. A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spectrophotometric
Spectrophotometry is a branch of electromagnetic spectroscopy concerned with the quantitative measurement of the reflection or transmission properties of a material as a function of wavelength. Spectrophotometry uses photometers, known as spectrophotometers, that can measure the intensity of a light beam at different wavelengths. Although spectrophotometry is most commonly applied to ultraviolet, visible, and infrared radiation, modern spectrophotometers can interrogate wide swaths of the electromagnetic spectrum, including x-ray, ultraviolet, visible, infrared, and/or microwave wavelengths. Overview Spectrophotometry is a tool that hinges on the quantitative analysis of molecules depending on how much light is absorbed by colored compounds. Important features of spectrophotometers are spectral bandwidth (the range of colors it can transmit through the test sample), the percentage of sample-transmission, the logarithmic range of sample-absorption, and sometimes a percentage of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sodium Citrate
Sodium citrate may refer to any of the sodium salts of citric acid (though most commonly the third): * Monosodium citrate * Disodium citrate * Trisodium citrate The three forms of salt are collectively known by the E number E331. Applications Food Sodium citrates are used as acidity regulators in food and drinks, and also as emulsifiers for oils. They enable cheeses to melt without becoming greasy. It reduces the acidity of food as well. Blood clotting inhibitor Sodium citrate is used to prevent donated blood from clotting in storage. It is also used in a laboratory, before an operation, to determine whether a person's blood is too thick and might cause a blood clot, or if the blood is too thin to safely operate. Sodium citrate is used in medical contexts as an alkalinizing agent in place of sodium bicarbonate, to neutralize excess acid in the blood and urine. Metabolic acidosis It has applications for the treatment of metabolic acidosis and chronic kidney disease. Ferr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NESFA
The New England Science Fiction Association, or NESFA, is a science fiction club centered in the New England area. It was founded in 1967, "by fans who wanted to ''do'' things in addition to socializing". NESFA is currently registered as a non-profit literary organization under IRS section 501(c)(3). The organization holds regular meetings (at their dedicated site, the NESFA Clubhouse) of and for members and other interested parties. A weekly meeting is held most Wednesday evenings, for socializing, projects, and miscellaneous business. Two weekend meetings are held every month: a Business Meeting (for administration), and the Other Meeting. The club also publishes a regular newsletter, ''Instant Message''. There are two book groups that meet on a monthly basis, as well as a monthly Game Day, and a monthly Game Night. In addition, there is a monthly Media day. This involves showings of two episodes of an anime series, two TV series episodes and a movie choice. All are science ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Filk
Filk music is a musical culture, genre, and community tied to science fiction, fantasy, and horror fandom and a type of fan labor. The genre has existed since the early 1950s and been played primarily since the mid-1970s. Etymology and definitions The term "filk" (originally a typographical error) predates 1955. (See also below.) As Interfilk's "What is it?" page demonstrates, there is no consensus on the definition of filk. Filk has been defined as what is sung or performed by the network of people who originally gathered to sing at science fiction or fantasy conventions. Another definition focuses on filking as a community of those who are interested in filk music and who form part of the social network self-identified with filking. As described later in this article, the origins of filk in science fiction conventions and its current organization emphasizes the social-network aspect of filking. The social aspect of filk as contrasted with the "performer vs. audience" d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Irish Language
Irish ( Standard Irish: ), also known as Gaelic, is a Goidelic language of the Insular Celtic branch of the Celtic language family, which is a part of the Indo-European language family. Irish is indigenous to the island of Ireland and was the population's first language until the 19th century, when English gradually became dominant, particularly in the last decades of the century. Irish is still spoken as a first language in a small number of areas of certain counties such as Cork, Donegal, Galway, and Kerry, as well as smaller areas of counties Mayo, Meath, and Waterford. It is also spoken by a larger group of habitual but non-traditional speakers, mostly in urban areas where the majority are second-language speakers. Daily users in Ireland outside the education system number around 73,000 (1.5%), and the total number of persons (aged 3 and over) who claimed they could speak Irish in April 2016 was 1,761,420, representing 39.8% of respondents. For most of recorded ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Irish Washerwoman
"The Irish Washerwoman" is a traditional jig known to have been played throughout Britain and Ireland and in North America. Although usually considered an Irish tune, some scholars claim that it is English in origin, derived from the seventeenth-century tune "Dargason". This jig was incorporated as the first movement of the ''Irish Suite'', a collection of traditional tunes arranged for orchestra by American composer Leroy Anderson in 1946. Over the years many songs have used ''The Irish Washerwoman'' tune. One of the most popularly known lyrics sung to the tune is ''McTavish Is Dead''. In popular culture The song has been used in many movies, such as ''Christmas in Connecticut'' and '' Master and Commander: The Far Side of the World''. In the ''Little House on the Prairie'' book series, Pa Ingalls plays the song on his fiddle. The Dutch group The Jumping Jewels recorded a version which reached No. 9 on the Dutch Charts. References External linksA clipof John Sheahan and An ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Java
Java (; id, Jawa, ; jv, ꦗꦮ; su, ) is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea to the north. With a population of 151.6 million people, Java is the world's List of islands by population, most populous island, home to approximately 56% of the Demographics of Indonesia, Indonesian population. Indonesia's capital city, Jakarta, is on Java's northwestern coast. Many of the best known events in Indonesian history took place on Java. It was the centre of powerful Hindu-Buddhist empires, the Islamic sultanates, and the core of the colonial Dutch East Indies. Java was also the center of the History of Indonesia, Indonesian struggle for independence during the 1930s and 1940s. Java dominates Indonesia politically, economically and culturally. Four of Indonesia's eight UNESCO world heritage sites are located in Java: Ujung Kulon National Park, Borobudur Temple, Prambanan Temple, and Sangiran Early Man Site. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frankincense
Frankincense (also known as olibanum) is an aromatic resin used in incense and perfumes, obtained from trees of the genus ''Boswellia'' in the family Burseraceae. The word is from Old French ('high-quality incense'). There are several species of ''Boswellia'' that produce true frankincense: ''Boswellia sacra'' ( syn. ''B. bhaw-dajiana'', syn. ''B. carteri''), '' B. frereana'', '' B. serrata'' (''B. thurifera'', Indian frankincense), and '' B. papyrifera''. Resin from each is available in various grades, which depend on the time of harvesting. The resin is hand-sorted for quality. Etymology and other names The English word ''frankincense'' derives from the Old French expression , meaning 'high-quality incense'. The word in Old French meant 'noble, pure'. Although named ''frank''incense, the name is not referring to the Franks. The name of frankincense in Koine Greek (the language of the New Testament): grc-koi, λίβανος, translit=lÃbanos, label=none (or grc-koi, λιΠ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Etymology
Etymology ()The New Oxford Dictionary of English (1998) – p. 633 "Etymology /ˌɛtɪˈmɒlədʒi/ the study of the class in words and the way their meanings have changed throughout time". is the study of the history of the Phonological change, form of words and, by extension, the origin and evolution of their semantic meaning across time. It is a subfield of historical linguistics, and draws upon comparative semantics, Morphology_(linguistics), morphology, semiotics, and phonetics. For languages with a long recorded history, written history, etymologists make use of texts, and texts about the language, to gather knowledge about how words were used during earlier periods, how they developed in Semantics, meaning and Phonological change, form, or when and how they Loanword, entered the language. Etymologists also apply the methods of comparative linguistics to reconstruct information about forms that are too old for any direct information to be available. By analyzing related ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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