Salicylic acid is a lipophilic monohydroxybenzoic acid, a type of phenolic acid, a beta hydroxy acid. It has the formula C7H6O3; this colorless crystalline organic acid is used in organic synthesis and functions as a plant hormone. It is derived from the metabolism of salicin. In addition to serving as an important active metabolite of aspirin, which acts in part as a prodrug to salicylic acid, it is best known for its use as a key ingredient in topical anti-acne products; the salts and esters of salicylic acid are known as salicylates. It is on the WHO Model List of Essential Medicines, the most important medications needed in a basic health system. Salicylic acid as a medication is used most to help remove the outer layer of the skin; as such, it is used to treat warts, acne, ringworm and ichthyosis. Similar to other hydroxy acids, salicylic acid is a key ingredient in many skincare products for the treatment of seborrhoeic dermatitis, psoriasis, corns, keratosis pilaris, acanthosis nigricans and warts.
Salicylic acid is used in the production of other pharmaceuticals, including 4-aminosalicylic acid and landetimide. Salicylic acid was one of the original starting materials for making acetylsalicylic acid in 1897. Bismuth subsalicylate, a salt of bismuth and salicylic acid, is the active ingredient in stomach relief aids such as Pepto-Bismol, is the main ingredient of Kaopectate and "displays anti-inflammatory action and acts as an antacid and mild antibiotic". Other derivatives include methyl salicylate used as a liniment to soothe joint and muscle pain and choline salicylate used topically to relieve the pain of mouth ulcers. Salicylic acid is used as a bactericidal and an antiseptic. Sodium salicylate is a useful phosphor in the vacuum ultraviolet spectral range, with nearly flat quantum efficiency for wavelengths between 10 and 100 nm, it fluoresces in the blue at 420 nm. It is prepared on a clean surface by spraying a saturated solution of the salt in methanol followed by evaporation. Aspirin can be prepared by the esterification of the phenolic hydroxyl group of salicylic acid with the acetyl group from acetic anhydride or acetyl chloride.
Salicylic acid directly and irreversibly inhibits the activity of both types of cyclo-oxygenases to decrease the formation of precursors of prostaglandins and thromboxanes from arachidonic acid. Salicylate may competitively inhibit prostaglandin formation. Salicylate's antirheumatic actions are a result of its anti-inflammatory mechanisms. Salicylic acid works by causing the cells of the epidermis to slough off more preventing pores from clogging up, allowing room for new cell growth. Salicylic acid inhibits the oxidation of uridine-5-diphosphoglucose competitively with nicotinamide adenosine dinucleotide and noncompetitively with UDPG, it competitively inhibits the transferring of glucuronyl group of uridine-5-phosphoglucuronic acid to the phenolic acceptor. The wound-healing retardation action of salicylates is due to its inhibitory action on mucopolysaccharide synthesis; as a topical agent and as a beta-hydroxy acid, salicylic acid is capable of penetrating and breaking down fats and lipids, causing moderate chemical burns of the skin at high concentrations.
It may damage the lining of pores if the solvent is acetone or an oil. Over-the-counter limits are set at 2% for topical preparations expected to be left on the face and 3% for those expected to be washed off, such as acne cleansers or shampoo. For wart removal, such a solution should be applied once or twice a day – more frequent use may lead to an increase in side-effects without an increase in efficacy; some people are hypersensitive to related compounds. If high concentrations of salicylic ointment are applied to a large percentage of body surface, high levels of salicylic acid can enter the blood, requiring hemodialysis to avoid further complications. Salicylic acid has the formula C6H4COOH, it is known as 2-hydroxybenzoic acid. It is poorly soluble in water. Salicylic acid is biosynthesized from the amino acid phenylalanine. In Arabidopsis thaliana it can be synthesized via a phenylalanine-independent pathway. Sodium salicylate is commercially prepared by treating sodium phenolate with carbon dioxide at high pressure and high temperature – a method known as the Kolbe-Schmitt reaction.
Acidification of the product with sulfuric acid gives salicylic acid: It can be prepared by the hydrolysis of aspirin or methyl salicylate with a strong acid or base. Hippocrates, Pliny the Elder and others knew that willow bark could ease pain and reduce fevers, it was used in China to treat these conditions. This remedy is mentioned in texts from ancient Egypt and Assyria; the Cherokee and other Native Americans used an infusion of the bark for fever and other medicinal purposes. In 2014, archaeologists identified traces of salicylic acid on 7th century pottery fragments found in east central Colorado; the Reverend Edward Stone, a vicar from Chipping Norton, Engla
Food coloring, or color additive, is any dye, pigment or substance that imparts color when it is added to food or drink. They come in many forms consisting of liquids, powders and pastes. Food coloring is used both in domestic cooking. Food colorants are used in a variety of non-food applications including cosmetics, home craft projects, medical devices. People associate certain colors with certain flavors, the color of food can influence the perceived flavor in anything from candy to wine. Sometimes the aim is to simulate a color, perceived by the consumer as natural, such as adding red coloring to glacé cherries, but sometimes it is for effect, like the green ketchup that Heinz launched in 1999. Color additives are used in foods for many reasons including: To make food more attractive, appealing and informative Offset color loss due to exposure to light, temperature extremes and storage conditions Correct natural variations in color Enhance colors that occur Provide color to colorless and "fun" foods Allow consumers to identify products on sight, like candy flavors or medicine dosages The addition of colorants to foods is thought to have occurred in Egyptian cities as early as 1500 BC, when candy makers added natural extracts and wine to improve the products' appearance.
During the Middle Ages, the economy in the European countries was based on agriculture, the peasants were accustomed to producing their own food locally or trading within the village communities. Under feudalism, aesthetic aspects were not considered, at least not by the vast majority of the very poor population; this situation changed with urbanization at the beginning of the Modern Age, when trade emerged—especially the import of precious spices and colors. One of the first food laws, created in Augsburg, Germany, in 1531, concerned spices or colorants and required saffron counterfeiters to be burned. With the onset of the industrial revolution, people became dependent on foods produced by others; these new urban dwellers demanded food at low cost. Analytical chemistry was still primitive and regulations few; the adulteration of foods flourished. Heavy metal and other inorganic element-containing compounds turned out to be cheap and suitable to "restore" the color of watered-down milk and other foodstuffs, some more lurid examples being: Red lead and vermillion were used to color cheese and confectionery.
Copper arsenite was used to recolor used tea leaves for resale. It caused two deaths when used to color a dessert in 1860. Sellers at the time offered more than 80 artificial coloring agents, some invented for dyeing textiles, not foods. Thus, with potted meat and sauces taken at breakfast he would consume more or less Armenian bole, red lead, or bisulphuret of mercury. At dinner with his curry or cayenne he would run the chance of a second dose of mercury. Again his tea if mixed or green, he would not escape without the administration of a little Prussian blue... Many color additives had never been tested for toxicity or other adverse effects. Historical records show that injuries deaths, resulted from tainted colorants. In 1851, about 200 people were poisoned in England, 17 of them fatally, directly as a result of eating adulterated lozenges. In 1856, the first synthetic color, was developed by Sir William Henry Perkin and by the turn of the century, unmonitored color additives had spread through Europe and the United States in all sorts of popular foods, including ketchup, mustard and wine.
These were dubbed'coal-tar' colors because the starting materials were obtained from bituminous coal. Many synthesized dyes were easier and less costly to produce and were superior in coloring properties when compared to derived alternatives; some synthetic food colorants are diazo dyes. Diazo dyes are prepared by coupling of a diazonium compound with a second aromatic hydrocarbons; the resulting compounds contain conjugated systems that efficiently absorb light in the visible parts of the spectrum, i.e. they are colored. The attractiveness of the synthetic dyes is that their color and other attributes can be engineered by the design of the specific dyestuff; the color of the dyes can be controlled by selecting the number of azo-groups and various substituents. Yellow shades are achieved by using acetoacetanilide. Red colors are azo compounds; the pair indigo and indigo carmine exhibit the same blue color, but the former is soluble in lipids, the latter is water-soluble because it has been fitted with sulfonate functional groups.
Concerns over food safety led to numerous regulations throughout the world. German food regulations released in 1882 stipulated the exclusion of dangerous minerals such as arsenic, chromium, lead and zinc, which were used as ingredients in colorants. In contrast to today, these first laws followed the principle of a negative listing. In the United States, the Pure Food and Drug Act of 1906 reduced the permitted list of synthetic colors from 700 down to seven; the seven dyes approved were Ponceau 3R, erythrosine, indigotine (F
Clemens von Pirquet
Clemens Peter Freiherr von Pirquet was an Austrian scientist and pediatrician best known for his contributions to the fields of bacteriology and immunology. Born in Vienna, he studied theology at the University of Innsbruck and philosophy at the University of Leuven before he enrolled at the University of Graz where he became a doctor of medicine in 1900, he started practicing at the Children's Clinic in Vienna. In 1906 he noticed that patients who had received injections of horse serum or smallpox vaccine had quicker, more severe reactions to a second injection. He, along with Béla Schick, coined the word allergy to describe this hypersensitivity reaction. Soon after, the observation with smallpox led Pirquet to realize that tuberculin, which Robert Koch isolated from the bacteria that cause tuberculosis in 1890, might lead to a similar type of reaction. Charles Mantoux expanded upon Pirquet's ideas and the Mantoux test, in which tuberculin is injected into the skin, became a diagnostic test for tuberculosis in 1907.
In 1909 he declined proposals to take a position at the Pasteur Institute in Paris and to become a professor at the Johns Hopkins University. In 1910 he returned to Europe taking positions in Breslau and Vienna. On 28 February 1929 his wife committed suicide with potassium cyanide. Guido von Pirquet Who Named It - Pirquet U. S. National Library of Medicine – History of medicine Arthur M. Silverstein, Clemens Freiherr von Pirquet: Explaining immune complex disease in 1906 EAACI – Clemens von Pirquet FOUNDATION Clemens von Pirquet, Allergie 1910 Huber, Benedikt, "", Wien. Klin. Wochenschr. 118, pp. 718–27, doi:10.1007/s00508-006-0712-0, PMID 17186166 Huber, Benedikt, "", Wien. Klin. Wochenschr. 118, pp. 573–9, doi:10.1007/s00508-006-0701-3, PMID 17136331 Bergmann, K C, "", MMW Fortschritte der Medizin, 148, pp. 24–5, 27, PMID 16910402 Bukantz, Samuel C, "Clemens von Pirquet and the concept of allergie", J. Allergy Clin. Immunol. 109, pp. 724–6, doi:10.1067/mai.2002.123049, PMID 11980437 Slavin, R G, "The 10th annual Clemens von Pirquet lectureship.
Clinical disorders of the nose and their relationship to allergy", Annals of Allergy, 49, pp. 123–6, PMID 7051906 Bendiner, E, "Baron von Pirquet: the aristocrat who discovered and defined allergy", Hosp. Pract. 16, pp. 137, 141, 144 passim, PMID 6800919 Wyklicky, H, "", Wiener Medizinische Wochenschrift, 130, pp. 123–5, PMID 6989119 Kapus, G, "", Orvosi Hetilap, 120, pp. 1327–30, PMID 379734 Asperger, H, "", Pädiatrie und Pädologie, 14, pp. I–II, PMID 379746 "", MMW, Münchener Medizinische Wochenschrift, 120, p. 474, 1978, PMID 347265 Székely, S, "", Orvosi Hetilap, 115, pp. 1175–7, PMID 4597514 Rapaport, H G, "Clemens von Pirquet and allergy", Annals of Allergy, 31, pp. 467–75, PMID 4588535 TREIMAN, V V, "", Sovetskaia Meditsina, 28, pp. 151–3, PMID 14290647 WAGNER, R, "CLEMENS VON PIRQUET, DISCOVERER OF THE CONCEPT OF ALLERGY", Bulletin of the New York Academy of Medicine, 40, pp. 229–35, PMC 1750523, PMID 14130490 WAGNER, R, "", Wien. Klin. Wochenschr. 75, pp. 241–3, PMID 13998265 KUNDRATITZ, K, "", Wien.
Klin. Wochenschr. 66, pp. 217–20, PMID 13169763 Prof. Pirquet an der Kinderklinik in Wien, 1928. On YouTube Clemens von Pirquet on 50 Euro Gold Coin
Los Angeles the City of Los Angeles and known by its initials L. A. is the most populous city in California, the second most populous city in the United States, after New York City, the third most populous city in North America. With an estimated population of four million, Los Angeles is the cultural and commercial center of Southern California; the city is known for its Mediterranean climate, ethnic diversity and the entertainment industry, its sprawling metropolis. Los Angeles is the largest city on the West Coast of North America. Los Angeles is in a large basin bounded by the Pacific Ocean on one side and by mountains as high as 10,000 feet on the other; the city proper, which covers about 469 square miles, is the seat of Los Angeles County, the most populated county in the country. Los Angeles is the principal city of the Los Angeles metropolitan area, the second largest in the United States after that of New York City, with a population of 13.1 million. It is part of the Los Angeles-Long Beach combined statistical area the nation's second most populous area with a 2015 estimated population of 18.7 million.
Los Angeles is one of the most substantial economic engines within the United States, with a diverse economy in a broad range of professional and cultural fields. Los Angeles is famous as the home of Hollywood, a major center of the world entertainment industry. A global city, it has been ranked 6th in the Global Cities Index and 9th in the Global Economic Power Index; the Los Angeles metropolitan area has a gross metropolitan product of $1.044 trillion, making it the third-largest in the world, after the Tokyo and New York metropolitan areas. Los Angeles hosted the 1932 and 1984 Summer Olympics and will host the event for a third time in 2028; the city hosted the Miss Universe pageant twice, in 1990 and 2006, was one of 9 American cities to host the 1994 FIFA men's soccer World Cup and one of 8 to host the 1999 FIFA women's soccer World Cup, hosting the final match for both tournaments. Home to the Chumash and Tongva, Los Angeles was claimed by Juan Rodríguez Cabrillo for Spain in 1542 along with the rest of what would become Alta California.
The city was founded on September 4, 1781, by Spanish governor Felipe de Neve. It became a part of Mexico in 1821 following the Mexican War of Independence. In 1848, at the end of the Mexican–American War, Los Angeles and the rest of California were purchased as part of the Treaty of Guadalupe Hidalgo, becoming part of the United States. Los Angeles was incorporated as a municipality on April 4, 1850, five months before California achieved statehood; the discovery of oil in the 1890s brought rapid growth to the city. The completion of the Los Angeles Aqueduct in 1913, delivering water from Eastern California assured the city's continued rapid growth; the Los Angeles coastal area was settled by the Chumash tribes. A Gabrieleño settlement in the area was called iyáangẚ, meaning "poison oak place". Maritime explorer Juan Rodríguez Cabrillo claimed the area of southern California for the Spanish Empire in 1542 while on an official military exploring expedition moving north along the Pacific coast from earlier colonizing bases of New Spain in Central and South America.
Gaspar de Portolà and Franciscan missionary Juan Crespí, reached the present site of Los Angeles on August 2, 1769. In 1771, Franciscan friar Junípero Serra directed the building of the Mission San Gabriel Arcángel, the first mission in the area. On September 4, 1781, a group of forty-four settlers known as "Los Pobladores" founded the pueblo they called El Pueblo de Nuestra Señora la Reina de los Ángeles,'The Town of Our Lady the Queen of the Angels'; the present-day city has the largest Roman Catholic Archdiocese in the United States. Two-thirds of the Mexican or settlers were mestizo or mulatto, a mixture of African and European ancestry; the settlement remained a small ranch town for decades, but by 1820, the population had increased to about 650 residents. Today, the pueblo is commemorated in the historic district of Los Angeles Pueblo Plaza and Olvera Street, the oldest part of Los Angeles. New Spain achieved its independence from the Spanish Empire in 1821, the pueblo continued as a part of Mexico.
During Mexican rule, Governor Pío Pico made Los Angeles Alta California's regional capital. Mexican rule ended during the Mexican–American War: Americans took control from the Californios after a series of battles, culminating with the signing of the Treaty of Cahuenga on January 13, 1847. Railroads arrived with the completion of the transcontinental Southern Pacific line to Los Angeles in 1876 and the Santa Fe Railroad in 1885. Petroleum was discovered in the city and surrounding area in 1892, by 1923, the discoveries had helped California become the country's largest oil producer, accounting for about one-quarter of the world's petroleum output. By 1900, the population had grown to more than 102,000; the completion of the Los Angeles Aqueduct in 1913, under the supervision of William Mulholland, assured the continued growth of the city. Due to clauses in the city's charter that prevented the City of Los Angeles from selling or providing water from the aqueduct to any area outside its borders, many adjacent city and communities became compelled to annex themselves into Los Angeles.
Los Angeles created the first municipal zoning ordinance in the United States. On September 14, 1908, the Los Angeles City Council promulgated residential and industrial land use zones; the new ordinance established three residential zones of a single type, where industrial uses were
International Standard Serial Number
An International Standard Serial Number is an eight-digit serial number used to uniquely identify a serial publication, such as a magazine. The ISSN is helpful in distinguishing between serials with the same title. ISSN are used in ordering, interlibrary loans, other practices in connection with serial literature; the ISSN system was first drafted as an International Organization for Standardization international standard in 1971 and published as ISO 3297 in 1975. ISO subcommittee TC 46/SC 9 is responsible for maintaining the standard; when a serial with the same content is published in more than one media type, a different ISSN is assigned to each media type. For example, many serials are published both in electronic media; the ISSN system refers to these types as electronic ISSN, respectively. Conversely, as defined in ISO 3297:2007, every serial in the ISSN system is assigned a linking ISSN the same as the ISSN assigned to the serial in its first published medium, which links together all ISSNs assigned to the serial in every medium.
The format of the ISSN is an eight digit code, divided by a hyphen into two four-digit numbers. As an integer number, it can be represented by the first seven digits; the last code digit, which may be 0-9 or an X, is a check digit. Formally, the general form of the ISSN code can be expressed as follows: NNNN-NNNC where N is in the set, a digit character, C is in; the ISSN of the journal Hearing Research, for example, is 0378-5955, where the final 5 is the check digit, C=5. To calculate the check digit, the following algorithm may be used: Calculate the sum of the first seven digits of the ISSN multiplied by its position in the number, counting from the right—that is, 8, 7, 6, 5, 4, 3, 2, respectively: 0 ⋅ 8 + 3 ⋅ 7 + 7 ⋅ 6 + 8 ⋅ 5 + 5 ⋅ 4 + 9 ⋅ 3 + 5 ⋅ 2 = 0 + 21 + 42 + 40 + 20 + 27 + 10 = 160 The modulus 11 of this sum is calculated. For calculations, an upper case X in the check digit position indicates a check digit of 10. To confirm the check digit, calculate the sum of all eight digits of the ISSN multiplied by its position in the number, counting from the right.
The modulus 11 of the sum must be 0. There is an online ISSN checker. ISSN codes are assigned by a network of ISSN National Centres located at national libraries and coordinated by the ISSN International Centre based in Paris; the International Centre is an intergovernmental organization created in 1974 through an agreement between UNESCO and the French government. The International Centre maintains a database of all ISSNs assigned worldwide, the ISDS Register otherwise known as the ISSN Register. At the end of 2016, the ISSN Register contained records for 1,943,572 items. ISSN and ISBN codes are similar in concept. An ISBN might be assigned for particular issues of a serial, in addition to the ISSN code for the serial as a whole. An ISSN, unlike the ISBN code, is an anonymous identifier associated with a serial title, containing no information as to the publisher or its location. For this reason a new ISSN is assigned to a serial each time it undergoes a major title change. Since the ISSN applies to an entire serial a new identifier, the Serial Item and Contribution Identifier, was built on top of it to allow references to specific volumes, articles, or other identifiable components.
Separate ISSNs are needed for serials in different media. Thus, the print and electronic media versions of a serial need separate ISSNs. A CD-ROM version and a web version of a serial require different ISSNs since two different media are involved. However, the same ISSN can be used for different file formats of the same online serial; this "media-oriented identification" of serials made sense in the 1970s. In the 1990s and onward, with personal computers, better screens, the Web, it makes sense to consider only content, independent of media; this "content-oriented identification" of serials was a repressed demand during a decade, but no ISSN update or initiative occurred. A natural extension for ISSN, the unique-identification of the articles in the serials, was the main demand application. An alternative serials' contents model arrived with the indecs Content Model and its application, the digital object identifier, as ISSN-independent initiative, consolidated in the 2000s. Only in 2007, ISSN-L was defined in the
Virtual International Authority File
The Virtual International Authority File is an international authority file. It is a joint project of several national libraries and operated by the Online Computer Library Center. Discussion about having a common international authority started in the late 1990s. After a series of failed attempts to come up with a unique common authority file, the new idea was to link existing national authorities; this would present all the benefits of a common file without requiring a large investment of time and expense in the process. The project was initiated by the US Library of Congress, the German National Library and the OCLC on August 6, 2003; the Bibliothèque nationale de France joined the project on October 5, 2007. The project transitioned to being a service of the OCLC on April 4, 2012; the aim is to link the national authority files to a single virtual authority file. In this file, identical records from the different data sets are linked together. A VIAF record receives a standard data number, contains the primary "see" and "see also" records from the original records, refers to the original authority records.
The data are available for research and data exchange and sharing. Reciprocal updating uses the Open Archives Initiative Protocol for Metadata Harvesting protocol; the file numbers are being added to Wikipedia biographical articles and are incorporated into Wikidata. VIAF's clustering algorithm is run every month; as more data are added from participating libraries, clusters of authority records may coalesce or split, leading to some fluctuation in the VIAF identifier of certain authority records. Authority control Faceted Application of Subject Terminology Integrated Authority File International Standard Authority Data Number International Standard Name Identifier Wikipedia's authority control template for articles Official website VIAF at OCLC