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Reactive oxygen species

Reactive oxygen species are chemically reactive chemical species containing oxygen. Examples include peroxides, hydroxyl radical, singlet oxygen, alpha-oxygen; the reduction of molecular oxygen produces superoxide, the precursor of most other reactive oxygen species: O2 + e− → •O−2Dismutation of superoxide produces hydrogen peroxide: 2 H+ + •O−2 + •O−2 → H2O2 + O2Hydrogen peroxide in turn may be reduced, thus forming hydroxide ion and hydroxyl radical, or reduced to water: H2O2 + e− → HO− + •OH 2 H+ + 2 e− + H2O2 → 2 H2OIn a biological context, ROS are formed as a natural byproduct of the normal metabolism of oxygen and have important roles in cell signaling and homeostasis. However, during times of environmental stress, ROS levels can increase dramatically; this may result in significant damage to cell structures. Cumulatively, this is known as oxidative stress; the production of ROS is influenced by stress factor responses in plants, these factors that increase ROS production include drought, chilling, nutrient deficiency, metal toxicity and UV-B radiation.

ROS are generated by exogenous sources such as ionizing radiation. ROS are produced during a variety of biochemical reactions within the cell and within organelles such as mitochondria and endoplasmic reticulum. Mitochondria convert energy for the cell into adenosine triphosphate; the process of ATP production in the mitochondria, called oxidative phosphorylation, involves the transport of protons across the inner mitochondrial membrane by means of the electron transport chain. In the electron transport chain, electrons are passed through a series of proteins via oxidation-reduction reactions, with each acceptor protein along the chain having a greater reduction potential than the previous; the last destination for an electron along this chain is an oxygen molecule. In normal conditions, the oxygen is reduced to produce water. Another source of ROS production is the electron transfer reactions catalyzed by the mitochondrial P450 systems in steroidogenic tissues; these P450 systems are dependent on the transfer of electrons from NADPH to P450.

During this process, some react with O2 producing superoxide. To cope with this natural source of ROS, the steroidogenic tissues and testsis, have a large concentration of antioxidants such as vitamin C and β-carotene and anti-oxidant enzymes. If too much damage is present in mitochondria, a cell undergoes programmed cell death. ROS are produced in immune cell signaling via the NOX pathway. Phagocytic cells such as neutrophils and mononuclear phagocytes produce ROS when stimulated; the formation of ROS can be stimulated by a variety of agents such as pollutants, heavy metals, smoke, xenobiotics, or radiation. Ionizing radiation can generate damaging intermediates through the interaction with water, a process termed radiolysis. Since water comprises 55–60% of the human body, the probability of radiolysis is quite high under the presence of ionizing radiation. In the process, water loses an electron and becomes reactive. Through a three-step chain reaction, water is sequentially converted to hydroxyl radical, hydrogen peroxide, superoxide radical, oxygen.

The hydroxyl radical is reactive and removes electrons from any molecule in its path, turning that molecule into a free radical and thus propagating a chain reaction. However, hydrogen peroxide is more damaging to DNA than the hydroxyl radical, since the lower reactivity of hydrogen peroxide provides enough time for the molecule to travel into the nucleus of the cell, subsequently reacting with macromolecules such as DNA. Superoxide dismutases are a class of enzymes that catalyze the dismutation of superoxide into oxygen and hydrogen peroxide; as such, they are an important antioxidant defense in nearly all cells exposed to oxygen. In mammals and most chordates, three forms of superoxide dismutase are present. SOD1 is located in the cytoplasm, SOD2 in the mitochondria and SOD3 is extracellular; the first is a dimer. SOD1 and SOD3 contain zinc ions, while SOD2 has a manganese ion in its reactive centre; the genes are located on chromosomes 21, 6, 4, respectively. The SOD-catalysed dismutation of superoxide may be written with the following half-reactions: M+ − SOD + O−2 → Mn+ − SOD + O2 Mn+ − SOD + O−2 + 2H+ → M+ − SOD + H2O2.where M = Cu.

In this reaction the oxidation state of the metal cation oscillates between n and n + 1. Catalase, concentrated in peroxisomes located next to mitochondria, reacts with the hydrogen peroxide to catalyze the formation of water and oxygen. Glutathione peroxidase reduces hydrogen peroxide by transferring the energy of the reactive peroxides to a small sulfur-containing protein called glutathione; the sulfur contained in these enzymes acts as the reactive center, carrying reactive electrons from the peroxide to the glutathione. Peroxiredoxins degrade H2O2, within the mitochondria and nucleus. 2 H2O2 → 2 H2O + O2 2GSH + H2O2 → GS–SG + 2H2O Another type of reactive oxygen species is sing

Melkias Agustinus Pellaupessy

Melkias Agustinus Pellaupessy was an Indonesian politician born in Ambon, Dutch East Indies on May 15, 1906. At the age of 19, he entered public service as an official of the Home Department. From 1937 up to the outbreak of World War II, he held the position of Head of the Administration Division of that Department. After World War II, he served as Secretary to the Resident Commissioner of South Sulawesi. In August 1946, he became Trade Commissioner and held this position until his nomination as representative of the State of East Indonesia to Jakarta in April 1948. In August 1948, he was appointed as the Resident of the South Moluccas. In September 1949, he took part in the Round Table Conference at The Hague as a member of the Federal Consultative Assembly, representing the pro-federal faction. After returning to Indonesia from The Hague, Pellaupessy was attached as an expert in the federal affairs to the office of the Prime Minister of East Indonesia. On 25 February 1950, he was elected as the Speaker of the Senate of the United States of Indonesia and was installed on 27 February 1950.

During his term of office, Pellaupessy was sent abroad several times to represent Indonesia in international conferences. In October 1947, he went to the Netherlands to confer with official and private instances there on the economic problems with regard to the reconstruction of Indonesia. In 1947, he was appointed as the Vice Chairman of the Netherlands Delegation to the International Trade Conference in Havana. After the formation of the Natsir Cabinet, the first cabinet after the recognition of Indonesia, he was appointed as the Minister of Information, he was appointed as the State Minister in the Sukiman Cabinet. Bastiaans, W. Ch. J. Personalia, Jakarta Tim Penyusun Sejarah, Seperempat Abad Dewan Perwakilan Rakjat Republik Indonesia, Jakarta: Sekretariat DPR-GR Ministry of Information, Kami Perkenalkan, Jakarta: Archipel Printers & Editors

Hafler circuit

The Hafler circuit is a passive electronics circuit with the aim of getting derived surround sound or ambiophony from regular stereo recordings without using costly electronics. The Dynaquad system works using similar principles. Named after its early proponent audio engineer David Hafler, the circuit exploits the high amount of stereo separation in the front speakers. Using the circuit reduces this stereo separation by only about 2 dB; this type of system is called 2:2:4, since the rear channels are simulated from a two channel stereo track, with no actual extra tracks encoded. With this setup the rear speakers could be smaller and have a smaller frequency range than the front speakers; the rear sound level in a live performance recorded in stereo is reproduced about 7 dB below the front level, but audible. The rear ambient sounds and coughs from the audience are sometimes received out of phase by the stereo microphones, while sounds from the musicians are in synchronous phase. Thus, if rear speakers are fed with the difference between the stereo channels, audience noises and reverberation from the auditorium may be heard from behind the listener.

This can be most achieved by wiring two similar additional rear speakers in series between the live feeds from the stereo amplifier. Alternatively, one rear speaker can be used on its own; this is the type of quad setup used by Seeburg jukeboxes. In the early and mid-1970s, for example, Ferguson made two channel receivers with a built-in Hafler circuit. Philips had a similar circuit in their two channel receivers. Many receivers from middle price brands had such circuits, but without a volume control for the rear channels. More expensive brands had Hafler or similar circuits, because they thought such circuits increased the distortion of the sound. Most of Marantz' four channel receivers had a variable matrix called Vari-Matrix that could simulate four channel stereo from two channel sources in different ways and the listener could adapt the sound with a control; the Vari-Matrix could with good result play all matrix records. Technics by National Panasonic had a similar matrix decoder with two controls.

In the early 1970s, the words ambiophony and ambiophonic were synonymous with the words quadraphonic and four channel stereo. But around 1973 the words ambiophony and ambiophonic were used to describe simulated four channel stereo of the Hafler type. Ambiophonic could mean the so-called concert hall sound in opposite to a surround sound with instruments all around the listener; the concert hall sound means the listener hears all the instruments from the front, whereas the rear channels are used to give the listener the acoustic effect of sitting in a concert hall. Dynaquad Ambisonics Ambiophonics Azimuth co-ordinator Four-channel compact disc digital audio Matrix decoder Multitrack recording Octophonic sound

Marsden Wagner

Marsden Wagner, was a perinatologist and perinatal epidemiologist from California who served as a Director of Maternal and Child Health for the California State Health Department, Director of the University of Copenhagen-UCLA Health Research Center, Director of Women's and Children's Health for the World Health Organization. He was an outspoken supporter of midwifery. Marsden Wagner was born in 1930 in San Francisco, he studied at the University of California at Los Angeles, earning an M. D. clinical specialty training in pediatrics, perinatology and an advanced scientific degree in perinatal science. Following several years of full-time clinical practice and some years as a full-time faculty member at UCLA, he became a Director of Maternal and Child Health for the California State Health Department. After six years in Denmark as Director of the University of Copenhagen-UCLA Health Research Center, he was for 15 years Director of Women's and Children's Health for the World Health Organization, during which time he chaired the three consensus conferences convened by WHO on appropriate technology around the time of birth.

The 1985 WHO study Having a Baby in Europe, for which he was chair of the working party, was based on survey responses from 23 European countries and revealed great differences in practises. With extensive experience in maternity care in industrialized countries, including midwifery and the appropriate use of technology during pregnancy and birth, he consulted and lectured in over 50 countries and gave testimony before the US Congress, British Parliament, French National Assembly, Italian Parliament, Russian Parliament and others. Wagner was an outspoken supporter of midwifery. In a 1997 article he described how his dissatisfaction with the medical establishment developed during his graduate studies and led to his further study in public health and to his advocacy for midwives, his publications, in eleven different languages, include 131 scientific papers, 20 book chapters and 14 books, including Pursuing the Birth Machine, credited with creating a social model of birth, Creating Your Birth Plan His Born in the USA was described as a "scathing attack on professional standards of care" in The Women's Review of Books.

Marsden Wagner's former homepage at the Wayback Machine Articles by Marsden Wagner in Midwifery Today Interview on Living on Earth, March 2007 Clip from the 2008 documentary film The Business of Being Born, in which Wagner talks about Cytotec Wagner's last interview, for Midwifery Today in 2008

Alexandra Flood

Alexandra Flood is an Australian operatic soprano. Born in Cowes, Flood attended the Methodist Ladies' College and studied from 2007 until 2010 at the University of Melbourne. In 2011, she gained a Graduate Diploma of Journalism at the Royal Melbourne Institute of Technology, she continued from 2014 to 2016 at the Hochschule für Musik und Theater München. In 2014 she was awarded a Mike Walsh Fellowship. Flood was part of the 2014 Salzburg Festival's Young Singers Project and made her European stage debut there as Blonde in a production for children of Mozart's Die Entführung aus dem Serail and as Modistin in Richard Strauss's Der Rosenkavalier, her first leading role was Marguerite in May 2015 in Le petit Faust by Hervé at the Staatstheater am Gärtnerplatz, Munich. This was followed in October by the title role in Janáček's The Cunning Little Vixen for Pacific Opera, Sydney. In 2016, Flood became a Studio Artist at the Wolf Trap Opera Festival, she sang Violetta in Traviata Remixed at the Grachtenfestival in Amsterdam.

She sang Serpetta in Mozart's La finta giardiniera in September at the Niedersächsische Musiktage in Hanover, Germany. Her first appearance in Poland was as Norina opposite Mariusz Kwiecień in Donizetti's Don Pasquale at Opera Krakowska in 2017, a role she reprised in 2018 at the Vorarlberger Landestheater, Austria. 2018 saw her Australian stage debut as Tell's son, Jemmy, in Rossini's William Tell for Victorian Opera, Melbourne. On the concert stage, Flood sang in Carl Orff's Carmina Burana, Vivaldi's "Gloria", Saint-Saëns' Oratorio de Noël, Handel's Messiah, Haydn's The Seasons, Vaughan Williams' A Pastoral Symphony, she sang the Edna in Jonathan Dove's church opera Tobias and the Angel with the Munich Radio Orchestra under the baton of Ulf Schirmer. Flood has won grants and awards in Australia and Germany; the actress Georgia Flood is the author Morris West her grand-uncle. Official website Profile, The Opera Foundation for Young Australians Profile, SIAA Foundation, Liechtenstein Alexandra Flood's channel on YouTube "Regnava nel silenzio" on YouTube, from Lucia di Lammermoor

Bricktown, Oklahoma City

Bricktown is an entertainment district just east of downtown Oklahoma City, United States. It was a major warehouse district; the major attractions of the district are the Chickasaw Bricktown Ballpark, the navigable Bricktown Canal, the 16-screen Harkins movie theatre. Bricktown Entertainment District includes some 50 square city blocks bounded between the Oklahoma River on the south, I-235 on the east, Deep Deuce District to the North, the Oklahoma City Central Business District to the West; the general boundary of the Bricktown Core Development District is as follows: An area bordered by the BNSF Railway. The district is administered by the Bricktown Urban Design Committee, established by the City of Oklahoma City to oversee modifications to the buildings and new construction within the district. Downtown Oklahoma City Inc. is charged with maintenance and operations of the district and oversees promotion alongside the Oklahoma City Tourism and Visitors Bureau. All entities are united with the ultimate goal of preserving Bricktown's historic'warehouse district' flavor while allowing modern entertainment, commercial and residential development to flourish.

Four railroad companies had freight operations east of the Santa Fe tracks in what is now Bricktown in the late 19th and early 20th century. The first brick structures, which were only one or two stories, appeared between 1898 and 1903. Larger brick buildings were constructed between 1903 and 1911, the tallest brick buildings were built between 1911 and 1930. Working-class houses were built nearby. Oklahoma City's first black newspaper, the Black Dispatch, was located in Bricktown at 228 E. First. In that area was the first local chapter of the National Association for the Advancement of Colored People, founded in the early 20th century to work for the civil rights of African Americans; the decline of the area began with the onset of the Great Depression, which diminished businesses in the area. The growth of eastern suburbs and subsidized highways during and after World War II attracted many residents to newer housing. Railroads restructured and freight traffic moved to trucks and highways. By 1980, Bricktown had become a cluster of abandoned buildings.

In the 1990s, mayor Ron Norick persuaded Oklahoma City residents to approve a series of tax incentives to lure new businesses, but these were not sufficient. A visit to Indianapolis, which had beat the city in a competition for a new airline maintenance plant, led him to believe that Oklahoma City needed a vibrant downtown, it lacked the range of amenities to attract more residents and visitors. Along with Greater Oklahoma City Chamber President Ray Ackerman and their staffs developed the Metropolitan Area Projects or MAPS, which approval led to the construction of the Bricktown ballpark and a tree-lined, mile-long canal through the district, as well as other projects in downtown; the ballpark opened in 1998 and the canal opened in July 1999. Water taxis carry visitors to different stops along the canal, including many restaurants and nightclubs; the district contains a number of public sculptures and murals, including a monument to the Oklahoma Land Run. The Centennial Land Run Monument, a large bronze sculpture by artist Paul Moore, is at the south end of Bricktown Canal.

It commemorates the Land Run of 1889, which marked the opening of the Unassigned Lands area to settlement. This area is now a city park, open 24 hours a day, year round, there is no admission fee. An annual Bricktown Art Festival is held in mid-July. Amtrak's Heartland Flyer service to Fort Worth departs every morning from the old Santa Fe Depot, located by the west entrance to Bricktown, returns in the evenings. Official website Case, J. I. Plow Works Building Avery Building Voices of Oklahoma interview with Ray Ackerman. First person interview conducted with Ray Ackerman on September 30, 2009. Original audio and transcript archived with Voices of Oklahoma oral history project. Bricktown Urban Design Committee