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:
Hottest Latest Alphabetical (A-Z) Alphabetical (Z-A)
Type:
All Topic Review Biography
Topic Review
Mobile DNA
Mobile DNA is DNA that able to move to new locations throughout the genome. This process of movement is often called transposion, and the mobile DNA, transposons. Some mobile DNAs move by different mechanisms to transposons, but have similarities.
  • 1.4K
  • 27 Sep 2022
Topic Review
Antioxidant Activity of Natural Products
Natural products identified with potential antioxidant activity need to be further evaluated in the cellular model. Antioxidant activity of a large number of natural products will not extrapolate its performance in the biological system, either in vitro as cellular assays or in vivo as animal model studies. Thus, it is necessary to examine the bioavailability, metabolism and mechanism of action in a living system to prove potential antioxidant activities of new natural products.
  • 1.4K
  • 09 Dec 2021
Topic Review
Cryptomeria japonica
Cryptomeria japonica, a commercially important tree throughout Asia and the Azores Archipelago (Portugal), is currently waste/by-products of wood processing that can be converted into eco-friendly and high added-value products, such as essential oils (EOs), with social, environmental and economic impacts.
  • 1.4K
  • 07 Dec 2021
Topic Review
Algal Synthesis of Metallic Nanoparticles
Metal nanoparticles (NPs) have received much attention for potential applications in medicine (mainly in oncology, radiology and infectiology), due to their intriguing chemical, electronical, catalytical, and optical properties such as surface plasmon resonance (SPR) effect. They also offer ease in controlled synthesis and surface modification (e.g., tailored properties conferred by capping/protecting agents including N-, P-, COOH-, SH-containing molecules and polymers such as thiol, disulfide, ammonium, amine, and multidentate carboxylate), which allows (i) tuning their size and shape (e.g., star-shaped and/or branched) (ii) improving their stability, monodispersity, chemical miscibility, and activity, (iii) avoiding their aggregation and oxidation over time, (iv) increasing their yield and purity. The bottom-up approach, where the metal ions are reduced in the NPs grown in the presence of capping ligands, has been widely used compared to the top-down approach. Besides the physical and chemical synthesis methods, the biological method is gaining much consideration. Indeed, several drawbacks have been reported for the synthesis of NPs via physical (e.g., irradiation, ultrasonication) and chemical (e.g., electrochemisty, reduction by chemicals such as trisodium citrate or ascorbic acid) methods (e.g., cost, and/ortoxicity due to use of hazardous solvents, low production rate, use of huge amount of energy). However, (organic or inorganic) eco-friendly NPs synthesis exhibits a sustainable, safe, and economical solution. Thereby, a relatively new trend for fast and valuable NPs synthesis from (live or dead) algae (i.e., microalgae, macroalgae and cyanobacteria) has been observed, especially because of its massive presence on the Earth's crust and their unique properties (e.g., capacity to accumulate and reduce metallic ions, fast propagation).  This work highlights affordable, fast, eco-friendly, efficient and safe strategies to produce nanoparticles for theranostic purposes. 
  • 1.4K
  • 27 Oct 2020
Topic Review
Sjögren’s Syndrome
Sjögren’s syndrome (SS) is a chronic autoimmune inflammatory disease that affects primarily older women and is characterized by irreversible damage of the exocrine glands, including tear (xerophthalmia) and salivary glands (xerostomia). Secretory glands lose their functionality due to the infiltration of immune cells, which produce cytokines and cause inflammation. Primary SS is characterized by dry syndrome with or without systemic commitment in the absence of other pathologies. Secondary SS is accompanied by other autoimmune diseases with high activation of B lymphocytes and the production of autoantibodies, including the rheumatoid factor. Other cells, such as CD4+ T cells and mast cells (MCs), participate in SS inflammation. MCs are ubiquitous, but are primarily located close to blood vessels and nerves and can be activated early in autoimmune diseases to express a wide variety of cytokines and chemokines. In the SS acute phase, MCs react by generating chemical mediators of inflammation, tumor necrosis factor (TNF), and other pro-inflammatory cytokines such as interleukin (IL)-1 and IL-33.
  • 1.4K
  • 26 Oct 2020
Topic Review
Feeding Strategy of Dead-Wood Eaters
Decomposition of wood is a very difficult process. Wood is highly resistant to decay, and it’s not very nutritious to boot. It doesn’t provide good sustenance for the decomposers that feed on it – in fact, it may even lack key elements needed for their growth, development and maturation. The only two things it’s abundant in are carbohydrates cellulose and hemicellulose, but they’re simply not enough. Nevertheless, there are daredevils who aren't afraid of starvation and even thrive in the long, dark, winding tunnels dug in dead trees. How is it possible? It’s commonly thought that it’s the symbionts that process the dead wood in order to provide sustenance for saproxylic organisms. However, according to the law of the conservation of mass, this is insufficient because the constituent atoms of nutrients cannot be created by organisms from the available biomass. Therefore, the elemental composition of wood limits the available nutrients, although symbionts are able to increase the digestibility of woody matter and synthesize important organic compounds from nutrients furnished by dead wood. The nutrients required for insects to properly develop are transported to dead wood by fungi, resulting in a rearrangement of the nutritional composition of the wood during the first few years of decay. By consuming decomposed wood that is rich in fungal tissues, the dead wood eater is able to grow, develop and reach maturity.
  • 1.4K
  • 30 Oct 2020
Topic Review
Chronic Pain
Chronic pain is an unpleasant sensory and emotional experience that persists or recurs more than three months and may extend beyond the expected time of healing. Chronic pain occurs as a part of symptoms due to an underlying medical condition or remains despite successful treatment of the condition that originally caused it.
  • 1.4K
  • 11 Aug 2021
Topic Review
Jacobsen Syndrome
Jacobsen syndrome is a condition caused by a loss of genetic material from chromosome 11. Because this deletion occurs at the end (terminus) of the long (q) arm of chromosome 11, Jacobsen syndrome is also known as 11q terminal deletion disorder.
  • 1.4K
  • 23 Dec 2020
Topic Review
Architecture and Composition of the Intestinal Flora
Intestinal microorganisms are composed of bacteria, archaea, eukaryotes, and viruses, and more than 99% of them are bacteria. Approximately 1014 bacteria are known to constitute the intestinal flora in the adult gut, and this number is 10 times the number of human somatic cells.
  • 1.4K
  • 05 Aug 2022
Topic Review
Crocodile
Crocodiles (family Crocodylidae) or true crocodiles are large semiaquatic reptiles that live throughout the tropics in Africa, Asia, the Americas and Australia . The term crocodile is sometimes used even more loosely to include all extant members of the order Crocodilia, which includes the alligators and caimans (family Alligatoridae), the gharial and false gharial (family Gavialidae) among other extinct taxa. Although they appear similar, crocodiles, alligators and the gharial belong to separate biological families. The gharial, with its narrow snout, is easier to distinguish, while morphological differences are more difficult to spot in crocodiles and alligators. The most obvious external differences are visible in the head, with crocodiles having narrower and longer heads, with a more V-shaped than a U-shaped snout compared to alligators and caimans. Another obvious trait is that the upper and lower jaws of the crocodiles are the same width, and the teeth in the lower jaw fall along the edge or outside the upper jaw when the mouth is closed; therefore, all teeth are visible, unlike an alligator, which possesses in the upper jaw small depressions into which the lower teeth fit. Also, when the crocodile's mouth is closed, the large fourth tooth in the lower jaw fits into a constriction in the upper jaw. For hard-to-distinguish specimens, the protruding tooth is the most reliable feature to define the species' family. Crocodiles have more webbing on the toes of the hind feet and can better tolerate saltwater due to specialized salt glands for filtering out salt, which are present, but non-functioning, in alligators. Another trait that separates crocodiles from other crocodilians is their much higher levels of aggression. Crocodile size, morphology, behaviour and ecology differ somewhat among species. However, they have many similarities in these areas as well. All crocodiles are semiaquatic and tend to congregate in freshwater habitats such as rivers, lakes, wetlands and sometimes in brackish water and saltwater. They are carnivorous animals, feeding mostly on vertebrates such as fish, reptiles, birds and mammals, and sometimes on invertebrates such as molluscs and crustaceans, depending on species and age. All crocodiles are tropical species that, unlike alligators, are very sensitive to cold. They separated from other crocodilians during the Eocene epoch, about 55 million years ago. Many species are at the risk of extinction, some being classified as critically endangered.
  • 1.4K
  • 17 Nov 2022
  • Page
  • of
  • 1814
Featured Entry Collections
>>

Featured Books

>>
Encyclopedia of Social Sciences
Encyclopedia of COVID-19
Encyclopedia of Fungi
Encyclopedia of Digital Society, Industry 5.0 and Smart City
Video Production Service
Feedback