Your browser does not fully support modern features. Please upgrade for a smoother experience.
Subject:
All Disciplines Arts & Humanities Biology & Life Sciences Business & Economics Chemistry & Materials Science Computer Science & Mathematics Engineering Environmental & Earth Sciences Medicine & Pharmacology Physical Sciences Public Health & Healthcare Social Sciences
Sort by:
Most Viewed Latest Alphabetical (A-Z) Alphabetical (Z-A)
Filter:
All Topic Review Biography Peer Reviewed Entry Video Entry
Biography
Florian Goebel
Karl Florian Goebel (18 October 1972 — 10 September 2008) was a Germany astrophysicist attached to the Max Planck Institute for Physics in Munich. He had also been a member of DESY, a German-based research center that develops and runs several particle accelerators and detectors, most notably the ZEUS project. At the time of his death he was managing the MAGIC-II telescope project. His death
  • 1.4K
  • 27 Dec 2022
Topic Review
Aurilide Family
Aurilides are a class of depsipeptides occurring mainly in marine cyanobacteria. Members of the aurilide family have shown to exhibit strong cytotoxicity against various cancer cell lines. These compounds bear a pentapeptide, a polyketide, and an α-hydroxy ester subunit in their structure.
  • 1.4K
  • 18 Mar 2021
Biography
John S. Foster Jr.
John Stuart Foster Jr. (born September 18, 1922) is an American physicist, best known as the fourth director of Lawrence Livermore National Laboratory and as Director, Defense Research and Engineering under four Secretaries of Defense and two Presidents. Foster was born September 18, 1922 in New Haven, Connecticut. He received his Bachelor of Science degree in 1948 from McGill University, whe
  • 1.4K
  • 12 Dec 2022
Topic Review
Tumor Necrosis Factor Alpha
Tumor necrosis factor (TNF, cachexin, or cachectin; once named as tumor necrosis factor alpha or TNFα) is a cell signaling protein (cytokine) involved in systemic inflammation and is one of the cytokines that make up the acute phase reaction. It is produced chiefly by activated macrophages, although it can be produced by many other cell types such as CD4+ lymphocytes, NK cells, neutrophils, mast cells, eosinophils, and neurons. TNF is a member of the TNF superfamily, consisting of various transmembrane proteins with a homologous TNF domain. The primary role of TNF is in the regulation of immune cells. TNF, being an endogenous pyrogen, is able to induce fever, apoptotic cell death, cachexia, inflammation and to inhibit tumorigenesis and viral replication and respond to sepsis via IL1- & IL6-producing cells. Dysregulation of TNF production has been implicated in a variety of human diseases including Alzheimer's disease, cancer, major depression, psoriasis and inflammatory bowel disease (IBD). Though controversial, studies of depression and IBD are currently being linked to increased levels of TNF. Recombinant TNF is used as an immunostimulant under the INN tasonermin. TNF can be produced ectopically in the setting of malignancy and parallels parathyroid hormone both in causing secondary hypercalcemia and in the cancers with which excessive production is associated.
  • 1.4K
  • 10 Oct 2022
Topic Review
2009 Flu Pandemic Vaccine
The 2009 flu pandemic vaccines were influenza vaccines developed to protect against the pandemic H1N1/09 virus. These vaccines either contained inactivated (killed) influenza virus, or weakened live virus that could not cause influenza. The killed vaccine was injected, while the live vaccine was given as a nasal spray. Both these types of vaccine were produced by growing the virus in chicken eggs. Around three billion doses were produced, with delivery in November 2009.Cite error: Closing missing for tag providing a strong protective immune response and having similar safety profile to the usual seasonal influenza vaccine. However, about 30% of people already had some immunity to the virus, with the vaccine conferring greatest benefit on young people, since many older people are already immune through exposure to similar viruses in the past. The vaccine also provided some cross-protection against the 1918 flu pandemic strain. Early results (pre-25 December 2009) from an observational cohort of 248,000 individuals in Scotland showed the vaccine to be effective at preventing H1N1 influenza (95.0% effectiveness [95% confidence intervals 76.0–100.0%]) and influenza-related hospital admissions (64.7% [95% confidence intervals 12.0–85.8%]). Developing, testing, and manufacturing sufficient quantities of a vaccine is a process that takes many months. According to Keiji Fukuda of the World Health Organization, "There's much greater vaccine capacity than there was a few years ago, but there is not enough vaccine capacity to instantly make vaccines for the entire world's population for influenza." The nasal mist version of the vaccine started shipping on 1 October 2009.
  • 1.4K
  • 17 Oct 2022
Topic Review
Antioxidant Molecules from Plant Waste
The fruit, vegetable, legume, and cereal industries generate many wastes, representing an environmental pollution problem. However, these wastes are a rich source of antioxidant molecules such as terpenes, phenolic compounds, phytosterols, and bioactive peptides with potential applications mainly in the food and pharmaceutical industries, and they exhibit multiple biological properties including antidiabetic, anti-obesity, antihypertensive, anticancer, and antibacterial properties. The aforementioned has increased studies on the recovery of antioxidant compounds using green technologies to value plant waste, since they represent more efficient and sustainable processes. In this review, the main antioxidant molecules from plants are briefly described and the advantages and disadvantages of the use of conventional and green extraction technologies used for the recovery and optimization of the yield of antioxidant naturals are detailed; finally, recent studies on biological properties of antioxidant molecules extracted from plant waste are presented here.
  • 1.4K
  • 14 Mar 2021
Topic Review
Head Direction Cells
Head direction cells are type of neuron involved in spatial processing. Head direction (HD) cells are neurons found in a number of brain regions that increase their firing rates above baseline levels only when the animal's head points in a specific direction. They have been reported in rats, monkeys, mice, chinchillas and bats, but are thought to be common to all mammals, perhaps all vertebrates and perhaps even some invertebrates, and to underlie the "sense of direction". When the animal's head is facing in the cell's "preferred firing direction" these neurons fire at a steady rate (i.e., they do not show adaptation), but firing decreases back to baseline rates as the animal's head turns away from the preferred direction (usually about 45° away from this direction). HD cells are found in many brain areas, including the cortical regions of postsubiculum (also known as the dorsal presubiculum), retrosplenial cortex, and entorhinal cortex, and subcortical regions including the thalamus (the anterior dorsal and the lateral dorsal thalamic nuclei), lateral mammillary nucleus, dorsal tegmental nucleus and striatum. It is thought that the cortical head direction cells process information about the environment, while the subcortical ones process information about angular head movements. A striking characteristic of HD cells is that in most brain regions they maintain the same relative preferred firing directions, even if the animal is moved to a different room, or if landmarks are moved. This has suggested that the cells interact so as to maintain a unitary stable heading signal (see "Theoretical models"). Recently, however, a subpopulation of HD neurons has been found in the dysgranular part of retrosplenial cortex that can operate independently of the rest of the network, and which seems more responsive to environmental cues. The system is related to the place cell system, located in the hippocampus, which is mostly orientation-invariant and location-specific, whereas HD cells are mostly orientation-specific and location-invariant. However, HD cells do not require a functional hippocampus to express their head direction specificity. They depend on the vestibular system, and the firing is independent of the position of the animal's body relative to its head. Some HD cells exhibit anticipatory behaviour: the best match between HD activity and the animal's actual head direction has been found to be up to 95 ms in future. That is, activity of head direction cells predicts, 95 ms in advance, what the animal's head direction will be. This possibly reflects inputs from the motor system ("motor efference copy") preparing the network for an impending head turn. HD cells continue to fire in an organized manner during sleep, as if animals were awake. However, instead of always pointing toward the same direction—the animals are asleep and thus immobile—the neuronal "compass needle" moves constantly. In particular, during rapid eye movement sleep, a brain state rich in dreaming activity in humans and whose electrical activity is virtually indistinguishable from the waking brain, this directional signal moves as if the animal is awake: that is, HD neurons are sequentially activated, and the individual neurons representing a common direction during wake are still active, or silent, at the same time.
  • 1.4K
  • 16 Nov 2022
Topic Review
Morpha
In biology, polymorphism is the occurrence of two or more clearly different morphs or forms, also referred to as alternative phenotypes, in the population of a species. To be classified as such, morphs must occupy the same habitat at the same time and belong to a panmictic population (one with random mating). Put simply, polymorphism is when there are two or more possibilities of a trait on a gene. For example, there is more than one possible trait in terms of a jaguar's skin colouring; they can be light morph or dark morph. Due to having more than one possible variation for this gene, it is termed 'polymorphism'. However, if the jaguar has only one possible trait for that gene, it would be termed "monomorphic". For example, if there was only one possible skin colour that a jaguar could have, it would be termed monomorphic. The term polyphenism can be used to clarify that the different forms arise from the same genotype. Genetic polymorphism is a term used somewhat differently by geneticists and molecular biologists to describe certain mutations in the genotype, such as single nucleotide polymorphisms that may not always correspond to a phenotype, but always corresponds to a branch in the genetic tree. See below. Polymorphism is common in nature; it is related to biodiversity, genetic variation, and adaptation. Polymorphism usually functions to retain a variety of forms in a population living in a varied environment.:126 The most common example is sexual dimorphism, which occurs in many organisms. Other examples are mimetic forms of butterflies (see mimicry), and human hemoglobin and blood types. According to the theory of evolution, polymorphism results from evolutionary processes, as does any aspect of a species. It is heritable and is modified by natural selection. In polyphenism, an individual's genetic makeup allows for different morphs, and the switch mechanism that determines which morph is shown is environmental. In genetic polymorphism, the genetic makeup determines the morph. The term polymorphism also refers to the occurrence of structurally and functionally more than two different types of individuals, called zooids, within the same organism. It is a characteristic feature of cnidarians. For example, Obelia has feeding individuals, the gastrozooids; the individuals capable of asexual reproduction only, the gonozooids, blastostyles; and free-living or sexually reproducing individuals, the medusae. Balanced polymorphism refers to the maintenance of different phenotypes in population.
  • 1.4K
  • 11 Nov 2022
Topic Review
Ethnobotany, Phytochemistry, Pharmacological Activity of Genus Malachra L.
The genus Malachra L. belongs to the family Malvaceae. It includes herbs or subshrubs of nine accepted species with approximately thirty synonyms, and it has been widely used in community folk medicine to treat health problems including inflammation, nasal obstruction, leishmaniasis, malaria, childbirth, kidney disorders, fever, respiratory tract diseases, among others.
  • 1.4K
  • 10 Nov 2022
Biography
Valeri Kubasov
Valeri Nikolayevich Kubasov (Russian: Вале́рий Никола́евич Куба́сов; 7 January 1935 – 19 February 2014) was a Soviet/Russia n cosmonaut who flew on two missions in the Soyuz programme as a flight engineer: Soyuz 6 and Soyuz 19 (the Apollo–Soyuz mission), and commanded Soyuz 36 in the Intercosmos programme. On 21 July 1975, the Soyuz 7K-TM module used for ASTP lande
  • 1.4K
  • 30 Nov 2022
Biography
Florence Wambugu
Florence Muringi Wambugu (born 23 August 1953) is a Kenyan plant pathologist and virologist. She is known for her advocacy of using biotechnology to increase food production in Africa. She attended the University of Nairobi, Kenya, where she received her Bachelor of Science in botany and zoology. She obtained her Master of Science in pathology from North Dakota State University, United States
  • 1.4K
  • 09 Dec 2022
Topic Review
Metal Allergy
Metal allergies inflame the skin after it has been in contact with metal. They are a form of allergic contact dermatitis. They are becoming more common, (As of 2021), except in areas with regulatory countermeasures. People may become sensitized to certain metals by skin contact, usually by wearing or holding consumer products (including non-metal products, like textiles and leather treated with metals), or sometimes after exposure at work. Contact with damaged skin makes sensitization more likely. Medical implants may also cause allergic reactions. Diagnosis is by patch test, a method which does not work as well for metals as it does for some other allergens. Prevention and treatment consists of avoiding the metal allergen; there is no other treatment, (As of 2021). It can be difficult to identify and avoid the allergen, because many metals are common in the environment, and some are biologically necessary to humans. Regulations have successfully reduced the rates of some metal allergies in Europe, but are not widespread. The social and economic costs of metal allergies are high. Metal allergies are type IV allergies; the metals are haptens. The toxicity of some allergenic metals may contribute to the development of allergies.
  • 1.4K
  • 28 Apr 2023
Biography
Paul Joseph Kaesberg
Paul Joseph Kaesberg (September 26, 1923 – December 24, 2010) was a German biochemist and virologist[1] who was known worldwide for his extensive research regarding small viruses.[2] His research significantly contributed to the our overall understanding of viruses today. Kaesberg is also known for discovering icosahedral-shaped viruses and for using X-rays to study viruses.[3] Paul J. Kaes
  • 1.4K
  • 27 Dec 2022
Biography
Peter Mittelstaedt
Peter Mittelstaedt pseudonym Karl Rottmann (born November 24, 1929 in Leipzig - November 21, 2014 in Erftstadt), was a German physicist, philosopher, and scientific theorist.[1][2][3] After studying physics at the universities of Jena, Bonn, and Göttingen, with a doctorate in theoretical physics in Göttingen in 1956 with Werner Heisenberg, Mittelstaedt had research stays at CERN in Geneva a
  • 1.4K
  • 16 Dec 2022
Biography
Florian Bieber
David Florian Bieber (born 4 October 1973) is a Luxembourgian political scientist, historian and professor working on inter-ethnic relations, ethnic conflict and nationalism, focusing primarily on Balkans. In 1991-1992 he studied History, Political Science, Economics and Languages at Trinity College. He received Magister degree in History and Political Science with honors on the topic “Bosn
  • 1.4K
  • 23 Dec 2022
Biography
David W. Bates
David Bates (born June 5, 1957) is an American-born physician, biomedical informatician, and professor, who is internationally renowned for his work regarding the use of health information technology (HIT) to improve the safety and quality of healthcare, in particular by using Clinical Decision Support.[1] Dr. Bates has done especially important work in the area of medication safety. He began by
  • 1.4K
  • 29 Nov 2022
Biography
Edward Trifonov
Edward Nikolayevich Trifonov (Hebrew: אדוארד טריפונוב‎, Russian: Эдуapд Тpифoнoв; b. March 31, 1937) is a Russian-born Israeli molecular biophysicist and a founder of Israeli bioinformatics. In his research, he specializes in the recognition of weak signal patterns in biological sequences and is known for his unorthodox scientific methods. He discovered the 3-bp and 10-
  • 1.4K
  • 07 Dec 2022
Biography
J. W. Dunne
John William Dunne FRAeS (2 December 1875 – 24 August 1949) was a British soldier, aeronautical engineer and philosopher. As a young man he fought in the Second Boer War, before becoming a pioneering aeroplane designer in the early years of the 20th century. Dunne worked on automatically stable aircraft, many of which were of tailless swept wing design, to achieve the first certified stable ai
  • 1.4K
  • 15 Nov 2022
Biography
Lawrence N. Shaw
Lawrence N. Shaw (August 12, 1939 – August 19, 2017) was an American physicist, curator, artist and founder of Pi Day. Shaw worked at the San Francisco science museum The Exploratorium for 33 years, performing just about every function for the museum. He was a key member of the arts and technology community in the San Francisco Bay Area. Lawrence N. Shaw was born in Washington, D.C. on Aug
  • 1.4K
  • 25 Nov 2022
Biography
Dagmar Schipanski
Dagmar Elisabeth Schipanski (born 3 September 1943) is a German physicist, academic, and politician from the State of Thuringia. Best known for 1999 nomination as President of Germany by the conservative Christian Democratic Union (CDU) and its sister party, the Christian Social Union of Bavaria (CSU), Schipanski has held a variety of political and academic roles her during four-decade-long care
  • 1.4K
  • 15 Nov 2022
  • Page
  • of
  • 68
Featured Entry Collections
>>

Featured Reprints

>>
Encyclopedia of Digital Society, Industry 5.0 and Smart City
Encyclopedia of Engineering
Encyclopedia of Social Sciences
Encyclopedia of Medieval Royal Iconography
Academic Video Service
Feedback