A microcontroller is a small computer on a single metal-oxide-semiconductor integrated circuit chip. In modern terminology, it is less sophisticated than, a system on a chip. A microcontroller contains one or more CPUs along with memory and programmable input/output peripherals. Program memory in the form of ferroelectric RAM, NOR flash or OTP ROM is often included on chip, as well as a small amount of RAM. Microcontrollers are designed for embedded applications, in contrast to the microprocessors used in personal computers or other general purpose applications consisting of various discrete chips. Microcontrollers are used in automatically controlled products and devices, such as automobile engine control systems, implantable medical devices, remote controls, office machines, power tools and other embedded systems. By reducing the size and cost compared to a design that uses a separate microprocessor and input/output devices, microcontrollers make it economical to digitally control more devices and processes.
Mixed signal microcontrollers are common, integrating analog components needed to control non-digital electronic systems. In the context of the internet of things, microcontrollers are an economical and popular means of data collection and actuating the physical world as edge devices; some microcontrollers may use four-bit words and operate at frequencies as low as 4 kHz, for low power consumption. They have the ability to retain functionality while waiting for an event such as a button press or other interrupt. Other microcontrollers may serve performance-critical roles, where they may need to act more like a digital signal processor, with higher clock speeds and power consumption; the origins of both the microprocessor and the microcontroller can be traced back to the invention of the MOSFET known as the MOS transistor. It was invented by Mohamed M. Atalla and Dawon Kahng at Bell Labs in 1959, first demonstrated in 1960; the same year, Atalla proposed the concept of the MOS integrated circuit, an integrated circuit chip fabricated from MOSFETs.
By 1964, MOS chips had reached higher transistor density and lower manufacturing costs than bipolar chips. MOS chips further increased in complexity at a rate predicted by Moore's law, leading to large-scale integration with hundreds of transistors on a single MOS chip by the late 1960s; the application of MOS LSI chips to computing was the basis for the first microprocessors, as engineers began recognizing that a complete computer processor could be contained on a single MOS LSI chip. The first multi-chip microprocessors, the Four-Phase Systems AL1 in 1969 and the Garrett AiResearch MP944 in 1970, were developed with multiple MOS LSI chips; the first single-chip microprocessor was the Intel 4004, released on a single MOS LSI chip in 1971. It was developed by Federico Faggin, using his silicon-gate MOS technology, along with Intel engineers Marcian Hoff and Stan Mazor, Busicom engineer Masatoshi Shima, it was followed by the 4-bit Intel 4040, the 8-bit Intel 8008, the 8-bit Intel 8080. All of these processors required several external chips to implement a working system, including memory and peripheral interface chips.
As a result, the total system cost was several hundred dollars, making it impossible to economically computerize small appliances. MOS Technology introduced sub-$100 microprocessors, the 6501 and 6502, with the chief aim of addressing this economic obstacle, but these microprocessors still required external support and peripheral chips which kept the total system cost in the hundreds of dollars. One book credits TI engineers Gary Boone and Michael Cochran with the successful creation of the first microcontroller in 1971; the result of their work was the TMS 1000, which became commercially available in 1974. It combined read-only memory, read/write memory and clock on one chip and was targeted at embedded systems. During the early-to-mid-1970s, Japanese electronics manufacturers began producing microcontrollers for automobiles, including 4-bit MCUs for in-car entertainment, automatic wipers, electronic locks, dashboard, 8-bit MCUs for engine control. In response to the existence of the single-chip TMS 1000, Intel developed a computer system on a chip optimized for control applications, the Intel 8048, with commercial parts first shipping in 1977.
It combined ROM on the same chip with a microprocessor. Among numerous applications, this chip would find its way into over one billion PC keyboards. At that time Intel's President, Luke J. Valenter, stated that the microcontroller was one of the most successful products in the company's history, he expanded the microcontroller division's budget by over 25%. Most microcontrollers at this time had concurrent variants. One had EPROM program memory, with a transparent quartz window in the lid of the package to allow it to be erased by exposure to ultraviolet light; these erasable chips were used for prototyping. The other variant was either a mask programmed ROM or a PROM variant, only programmable once. For the latter, sometimes the designation OTP was used, standing for "one-time programmable". In an OTP microcontroller, the PROM was of identical type as the EPROM, but the chip package had no quartz window; because the er
Sphingosine is an 18-carbon amino alcohol with an unsaturated hydrocarbon chain, which forms a primary part of sphingolipids, a class of cell membrane lipids that include sphingomyelin, an important phospholipid. Sphingosine can be phosphorylated in vivo via two kinases, sphingosine kinase type 1 and sphingosine kinase type 2; this leads to the formation of a potent signaling lipid. Sphingolipid metabolites, such as ceramides and sphingosine-1-phosphate, are lipid signaling molecules involved in diverse cellular processes. Sphingosine is synthesized from palmitoyl CoA and serine in a condensation required to yield dehydrosphingosine. Dehydrosphingosine is reduced by NADPH to dihydrosphingosine, oxidized by FAD to sphingosine. There is no direct route of synthesis from sphinganine to sphingosine. Sphingosine is formed via degradation of sphingolipid in the lysosome. Dimethylsphingosine Fingolimod Radin N. "Killing tumours by ceramide-induced apoptosis: a critique of available drugs". Biochem J. 371: 243–56.
Doi:10.1042/BJ20021878. PMC 1223313. PMID 12558497. Article Carter, H. E. F. J. Glick, W. P. Norris, G. E. Phillips. 1947. Biochemistry of the sphingolipides. III. Structure of sphingosine. J. Biol. Chem. 170: 285–295 Sphingosine at the US National Library of Medicine Medical Subject Headings
Sprzedaja towar 10 razy drozej powołując się na nieistniejące patenty i srodowisko naukowe. Unikaja przyjecia zwrotów towarów zakupionych na odległość. Global HELP Organization is a 501 nonprofit organization working in the area of creating and distributing healthcare information for low-resource areas.. HELP stands for "Health Education using Low-cost Publications". Founded in 2002 by pediatric orthopedist Lana and Lynn Staheli, GHO distributes information in the form of PDFs and videos online and through DVD libraries. GHO has created 85 titles in 35 languages. Clubfoot: Ponseti Management is a guide written and published by GHO on the Ponseti method of treating clubfoot. Published in 2003, the guide has been translated into 30 languages and the PDF has been downloaded over 100,000 times in 150 countries, it was included in the World Health Organization Blue Trunk Library. The HELP Guide to Cerebral Palsy provides an overview of diagnosis and management techniques for cerebral palsy; the second edition was published by GHO in 2010.
Edited by Dr. Emmanuel Ameh, Paediatric Surgery: A Comprehensive Text for Africa was published by GHO in 2010 and includes chapters from 150 contributors; the focus of the two-volume book is on pediatric surgical problems in Africa and other low-resource areas around the world. 1,000 hard copies were printed and distributed throughout Africa in 2010 and the PDF version has been downloaded over 250,000 times from the GHO website. Written in 2010, The HELP Guide to Burn Contractures in Developing Countries discusses methods of burn treatment in underserved regions. GHO has 144 videos available on their YouTube channel. Nearly 38% of GHO's online user community resides in India; the United Kingdom, Russia and New Zealand rank in the top five countries that access materials on global-help.org