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HandWiki is the world's largest wiki-style encyclopedia dedicated to science, technology and computing. It allows you to create and edit articles as long as you have external citations and login account. In addition, this is a content management environment that can be used for collaborative editing of original scholarly content, such as books, manuals, monographs and tutorials.

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Industrial Enyzmes
Industrial enzymes are enzymes that are commercially used in a variety of industries such as pharmaceuticals, chemical production, biofuels, food & beverage, and consumer products. Due to advancements in recent years, biocatalysis through isolated enzymes is considered more economical than use of whole cells. Enzymes may be used as a unit operation within a process to generate a desired product, or may be the product of interest. Industrial biological catalysis through enzymes has experienced rapid growth in recent years due to their ability to operate at mild conditions, and exceptional chiral and positional specificity, things that traditional chemical processes lack. Isolated enzymes are typically used in hydrolytic and isomerization reactions. Whole cells are typically used when a reaction requires a co-factor. Although co-factors may be generated in vitro, it is typically more cost-effective to use metabolically active cells.
  • 853
  • 20 Oct 2022
Topic Review
Spongy Degeneration of the Central Nervous System
Spongy degeneration of the central nervous system, also known as Canavan's disease, Van Bogaert-Bertrand type or Aspartoacylase (AspA) deficiency, is a rare autosomal recessive neurodegenerative disorder. It belongs to a group of genetic disorders known as leukodystrophies, where the growth and maintenance of myelin sheath in the central nervous system (CNS) are impaired. There are three types of spongy degeneration: infantile, congenital and juvenile, with juvenile being the most severe type. Common symptoms in infants include lack of motor skills, weak muscle tone, and macrocephaly. It may also be accompanied by difficulties in feeding and swallowing, seizures and sleep disturbances. Affected children typically die before the age of 10, but life expectancy can vary. The cause of spongy degeneration of the CNS is the mutation in a gene coding for aspartoacylase (AspA), an enzyme that hydrolyzes N-acetyl aspartic acid (NAA). In the absence of AspA, NAA accumulates and results in spongy degeneration. The exact pathophysiological causes of the disease are currently unclear, but there are developing theories. Spongy degeneration can be diagnosed with neuroimaging techniques and urine examination. There is no current treatment for spongy degeneration, but research utilising gene therapy to treat the disease is underway. Spongy degeneration is found to be more prevalent among Ashkenazi Jews, with an incidence of 1/6000 amongst this ethnic group.
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  • 20 Oct 2022
Topic Review
Blood Typing
Blood typing is a medical laboratory test used to identify the antigens on a person's red blood cells, which determine their blood type. Routine blood typing involves determining the ABO and RhD (Rh factor) type, and is performed before blood transfusions to ensure that the donor blood is compatible. It is also used to help diagnose hemolytic disease of the newborn, a condition caused by incompatibility between the blood types of a mother and her baby. ABO typing involves both identification of ABO antigens on red blood cells (forward grouping) and identification of ABO antibodies in the plasma (reverse grouping). Other blood group antigens, such as RhC/c and E/e or Kell, may be tested for in special situations. Blood typing is usually performed using serologic methods, which use reagents containing antibodies, called antisera, to identify blood group antigens. Serologic methods rely on the ability of antibodies to cause red blood cells to clump together when they bind to antigens on the cell surface, a phenomenon called agglutination. A number of serologic methods are available, ranging from manual blood typing using test tubes or slides to fully automated systems. Blood types can also be determined through genetic testing, which is used when conditions that interfere with serologic testing are present or when a high degree of accuracy in antigen identification is required. A number of conditions can cause false or inconclusive results in blood typing. When these issues affect ABO typing, they are called ABO discrepancies. ABO discrepancies must be investigated and resolved before the person's blood type is reported. There are different procedures for resolving ABO discrepancies depending on the underlying causes. Other sources of error in blood typing include the "weak D" phenomenon, in which people who are positive for the RhD antigen show weak or negative reactions when tested for RhD, and the presence of Immunoglobulin G antibodies on red blood cells, which interferes with typing for some blood group antigens.
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  • 25 Oct 2022
Topic Review
Hungarian Soviet Republic
The Hungarian Soviet Republic, literally the Republic of Councils in Hungary (Hungarian: Magyarországi Tanácsköztársaság), also known as the Hungarian Socialist Federative Soviet Republic (Hungarian: Magyarországi Szocialista Szövetséges Tanácsköztársaság) was a short-lived (133 days) communist rump state. When the Republic of Councils in Hungary was established in 1919, it controlled approximately 23% of the territory of Hungary's classic pre-World War I territories (325 411 km2). It was the successor of the first Hungarian People's Republic and lasted from only 21 March to 1 August 1919. Though the de jure leader of the Hungarian Soviet Republic was president Sándor Garbai, the de facto power was in the hands of foreign minister Béla Kun, who maintained direct contact with Lenin via radiotelegraph. It was Lenin who gave the direct orders and advice to Béla Kun via constant radio communication with the Kremlin. It was the second socialist state in the world to be formed, preceded by only the October Revolution in Russia which brought the Bolsheviks to power. The Hungarian Republic of Councils had military conflicts with the Kingdom of Romania, the Kingdom of Serbs, Croats and Slovenes and the evolving Czechoslovakia. It ended on 1 August 1919 when Hungarians sent representatives to negotiate their surrender to the Romanian forces. Due to the mistranslation, it is often referred to as "Hungarian Soviet republic" in English sources, despite the literal name "Republic of Councils in Hungary" was chosen for the purpose to avoid any strong ethnic connotation with Hungarian people, and express the Proletarian internationalist doctrine of the new Communist regime.
  • 6.8K
  • 20 Oct 2022
Topic Review
AKG
AKG Acoustics (originally Akustische und Kino-Geräte Gesellschaft m.b.H., English: Acoustic and Cinema Equipment L.L.C.) is an acoustics engineering and manufacturing company. It was founded in 1947 by Dr. Rudolf Görike and Ernest Plass in Vienna, Austria. It is a part of Harman International Industries, a subsidiary of Samsung Electronics. The products currently marketed under the AKG brand mostly consist of microphones, headphones, wireless audio systems and related accessories for professional and consumer markets.
  • 2.9K
  • 20 Oct 2022
Topic Review
Electronic Ticket
An electronic ticket (commonly abbreviated as e-ticket) is the digital ticket equivalent of a paper ticket. The term is most commonly associated with airline issued tickets. Electronic ticketing for urban or rail public transport is usually referred to as travel card or transit pass. It is also used in ticketing in the entertainment industry. An electronic ticket system is a more efficient method of ticket entry, processing and marketing for companies in the airline, railways and other transport and entertainment industries.
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  • 20 Oct 2022
Topic Review
In-band On-channel
In-band on-channel (IBOC) is a hybrid method of transmitting digital radio and analog radio broadcast signals simultaneously on the same frequency. By utilizing additional digital subcarriers or sidebands, digital information is "multiplexed" on an AM or FM analog signal, thus avoiding re-allocation of the broadcast bands. However, by putting RF energy outside of the normally-defined channel, interference to adjacent channel stations is increased when using digital sidebands. The addition of the digital sidebands works better in the United States, where the FM broadcast band channels have a spacing of 200 kHz, as opposed to the 100 kHz that is normal elsewhere. The 200 kHz spacing means that in practice, stations having concurrent or adjacent coverage areas will not be spaced at less than 400 kHz. Outside of the US, spacing can be 300 kHz, which causes problems with the IBOC digital sidebands. IBOC does allow for multiple program channels, though this can entail taking some existing subcarriers off the air to make additional bandwidth available in the modulation baseband. On FM, this could eventually mean removing stereo. On AM, IBOC is incompatible with analog stereo, and any additional channels are limited to highly compressed voice, such as traffic and weather. Eventually, stations can go from hybrid mode (both analog and digital) to all-digital, by eliminating the baseband monophonic audio.
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  • 20 Oct 2022
Topic Review
Ideal Lattice Cryptography
Ideal lattices are a special class of lattices and a generalization of cyclic lattices. Ideal lattices naturally occur in many parts of number theory, but also in other areas. In particular, they have a significant place in cryptography. Micciancio defined a generalization of cyclic lattices as ideal lattices. They can be used in cryptosystems to decrease by a square root the number of parameters necessary to describe a lattice, making them more efficient. Ideal lattices are a new concept, but similar lattice classes have been used for a long time. For example cyclic lattices, a special case of ideal lattices, are used in NTRUEncrypt and NTRUSign. Ideal lattices also form the basis for quantum computer attack resistant cryptography based on the Ring Learning with Errors. These cryptosystems are provably secure under the assumption that the Shortest Vector Problem (SVP) is hard in these ideal lattices.
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  • 20 Oct 2022
Topic Review
Woodcock–Johnson Tests of Cognitive Abilities
The Woodcock–Johnson Tests of Cognitive Abilities is a set of intelligence tests first developed in 1977 by Richard Woodcock and Mary E. Bonner Johnson (although Johnson's contribution is disputed). It was revised in 1989, again in 2001, and most recently in 2014; this last version is commonly referred to as the WJ IV. They may be administered to children from age two right up to the oldest adults (with norms utilizing individuals in their 90s). The previous edition WJ III was praised for covering "a wide variety of cognitive skills".
  • 3.4K
  • 20 Oct 2022
Topic Review
Fashion Influencer
A fashion influencer is a personality that has a large number of followers on social media, creates mainly fashion content and has the power to influence the opinion and purchase behavior of others with their recommendations. Brands endorse them to attend fashion shows, parties, designer dinners and exclusive trips and to wear their clothes on social media. If a salary has been involved, the influencer may be required to label such posts as paid or sponsored content. Before social media "they would have been called 'It girls'". Business magazine Forbes identified fashion influencers as "the new celebrity endorsements". However, influencers seem to have a closer relationship with their audience than traditional celebrities. As marketers Jung von Matt, Brandnew IO and Facelift point out: "Daily interactions across multiple channels, through photos, stories or live sessions, create a form of closeness and trust" that make influencers "often more tangible than traditional celebrities".
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  • 20 Oct 2022
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