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Topic Review
Extra (Acting)
A background actor or extra is a performer in a film, television show, stage, musical, opera or ballet production, who appears in a nonspeaking or nonsinging (silent) capacity, usually in the background (for example, in an audience or busy street scene). War films and epic films often employ background actors in large numbers: some films have featured hundreds or even thousands of paid background actors as cast members (hence the term "cast of thousands"). Likewise, grand opera can involve many background actors appearing in spectacular productions. On a film or TV set, background actors are usually referred to as "junior artist", "atmosphere", "background talent", "background performers", "background artists", "background cast members" or simply "background", while the term "extra" is rarely used. In a stage production, background actors are commonly referred to as "supernumeraries". In opera and ballet, they are called either "extras" or "supers".
  • 2.3K
  • 04 Nov 2022
Topic Review
Spacewalk
Spacewalk is open-source systems management software for system provisioning, patching and configuration licensed under the GNU GPLv2. The project was discontinued on 31 May 2020 with 2.10 being the last official release. SUSE forked the spacewalk code base in 2018 with uyuni-project.
  • 2.3K
  • 15 Nov 2022
Topic Review
Automatic Wheelchairs
Automatic wheelchairs refers to devices equipped with wheelchairs, which can move automatically. Automatic wheelchairs have evolved in terms of instrumentation and control, improving the mobility of people with physical disabilities. The different wheelchair control techniques are divided into two categories: sensor technology non-invasively placed on the user and wheelchair instrumentation.
  • 2.3K
  • 26 Nov 2020
Topic Review
Biomedical Applications of Quaternized Chitosan
The natural polymer chitosan is the second most abundant biopolymer on earth after chitin and has been extensively explored for preparation of versatile drug delivery systems. The presence of two distinct reactive functional groups (an amino group at C2, and a primary and secondary hydroxyl group at C3 and C6) of chitosan are involved in the transformation of expedient derivatives such as acylated, alkylated, carboxylated, quaternized and esterified chitosan. Amongst these, quaternized chitosan is preferred in pharmaceutical industries owing to its prominent features including superior water solubility, augmented antimicrobial actions, modified wound healing, pH-sensitive targeting, biocompatibility, and biodegradability. It has been explored in a large realm of pharmaceuticals, cosmeceuticals, and the biomedical arena. Immense classy drug delivery systems containing quaternized chitosan have been intended for tissue engineering, wound healing, gene, and vaccine delivery. 
  • 2.3K
  • 11 Aug 2021
Topic Review
Fluid Resuscitation in Sepsis
The importance of fluid resuscitation therapy during the early stages of sepsis management is a well-established principle. Current Surviving Sepsis Campaign (SSC) guidelines recommend the early administration of intravenous crystalloid fluids for sepsis-related hypotension or hyperlactatemia due to tissue hypoperfusion, within the first 3 h of resuscitation and suggest using balanced solutions (BSs) instead of normal saline (NS) for the management of patients with sepsis or septic shock.
  • 2.3K
  • 08 Jun 2023
Topic Review
Bioglass 45S5
Oxides of sodium, calcium, silicon, and phosphorus form the Na2O–CaO–SiO2–P2O5 system, of which the most famous material—Bioglass 45S5—was developed in 1969 by Professor Larry Hench. In the middle of the 1980s, Bioglass 45S5 was introduced to the market, and it stimulated many research groups to an intensive investigation of bioactive glasses and their further applications.
  • 2.3K
  • 29 Dec 2023
Topic Review
Magneto-Fluorescent Nanosystems for Biomodal Imaging
The various imaging techniques used in clinic have advantages and disadvantages. The advent of nanotechnology offers the possibility to combine several imaging agents within the same nano-object. This will allow to perform multi-imaging and thus obtain additional information during the same clinical procedure. Here, the focus are made on the potentialities of biomodal agents labeled for MRI and optical imaging. The three main associations for obtaining magneto-fluorescent objects will be presented: (1) association by covalent bonding; (2) encapsulation in matrices; (3) dispersion in nanoassemblies.
  • 2.3K
  • 13 Oct 2021
Topic Review
Saffron for the Treatment of Human Diseases
Saffron (Crocus sativus L.) is a medicinal plant, originally cultivated in the East and Middle East, and later in some Mediterranean countries. Saffron is obtained from the stigmas of the plant. Currently, the use of saffron is undergoing a revival. The medicinal virtues of saffron, its culinary use and its high added value have led to the clarification of its phytochemical profile and its biological and therapeutic characteristics. Saffron is rich in carotenoids and terpenes. The major products of saffron are crocins and crocetin (carotenoids) deriving from zeaxanthin, pirocrocin and safranal, which give it its taste and aroma, respectively. Saffron and its major compounds have powerful antioxidant and anti-inflammatory properties in vitro and in vivo. Anti-tumor properties have also been described. 
  • 2.3K
  • 18 Feb 2022
Topic Review
Clean Development Mechanism
The Clean Development Mechanism (CDM) is one of the Flexible Mechanisms defined in the Kyoto Protocol (IPCC, 2007) that provides for emissions reduction projects which generate Certified Emission Reduction units (CERs) which may be traded in emissions trading schemes. The market crashed in 2012 when the value of credits collapsed and thousands of projects were left with unclaimed credits. The struggle about what to do with the old credits sank the 2019 COP 25 in Madrid. The CDM, defined in Article 12 of the Protocol, was intended to meet two objectives: "Annex I" parties are the countries listed in Annex I of the treaty, the industrialized countries. Non-Annex I parties are developing countries. The CDM addresses the second objective by allowing the Annex I countries to meet part of their emission reduction commitments under the Kyoto Protocol by buying Certified Emission Reduction units from CDM emission reduction projects in developing countries. Both the projects and the issue of CERs units are subject to approval to ensure that these emission reductions are real and "additional." The CDM is supervised by the CDM Executive Board (CDM EB) under the guidance of the Conference of the Parties (COP/MOP) of the United Nations Framework Convention on Climate Change (UNFCCC). The CDM allows industrialized countries to buy CERs and to invest in emission reductions where it is cheapest globally. Between 2001, which was the first year CDM projects could be registered and 7 September 2012, the CDM issued 1 billion Certified Emission Reduction units. As of 1 June 2013, 57% of all CERs had been issued for projects based on destroying either HFC-23 (38%) or N2O (19%). Carbon capture and storage (CCS) was included in the CDM carbon offsetting scheme in December 2011. However, a number of weaknesses of the CDM have been identified. Several of these issues were addressed by the new Program of Activities (PoA), which moves to approving 'bundles' of projects instead of accrediting each project individually. In 2012, the report Climate Change, Carbon Markets and the CDM: A Call to Action said governments urgently needed to address the future of the CDM. It suggested the CDM was in danger of collapse because of the low price of carbon and the failure of governments to guarantee its existence into the future. Writing on the website of the Climate & Development Knowledge Network, Yolanda Kakabadse, a member of the investigating panel for the report and founder of Fundación Futuro Latinamericano, said a strong CDM is needed to support the political consensus essential for future climate progress. "Therefore we must do everything in our hands to keep it working," she said.
  • 2.3K
  • 17 Oct 2022
Topic Review
Njangsa
The term Njangsa refers to an oily seeds tree, Ricinodendron heudelotii, found in tropical West Africa. It is also known as Munguella (Angola), Essessang (Cameroon), Bofeko (Zaire), Wama (Ghana), Okhuen (Nigeria), Kishongo (Uganda), Akpi (Côte d'Ivoire), Djansang, Essang, Ezezang and Njasang. Two varieties of the tree species are recognized R. heudelotii var. heudelotii in Ghana and R. heudelotii var. africanum in Nigeria and Westwards.
  • 2.3K
  • 01 Nov 2022
Topic Review
Liquid Crystal Elastomer
Liquid crystal elastomer (LCE) describes a class of materials that combine the elastic entropy behaviour associated with conventional elastomers with the stimuli responsive properties of anisotropic liquid crystals. LCEs consequently exhibit attributes of both elastomers and liquid crystals, but additionally have unique properties not found in either. Recent developments in LCE synthesis, as well as the understanding of the behaviour of liquid crystal elastomers—namely their mechanical, optical and responsive properties—is of significant relevance to biology and biomedicine. LCEs are abundant in nature, highlighting the potential use of LCEs in biomimetics. Their exceptional tensile properties and biocompatibility have led to research exploring their applications in artificial tissue, biological sensors and cell scaffolds by exploiting their actuation and shock absorption properties. There has also been significant recent interest in using LCEs as a model for morphogenesis.
  • 2.3K
  • 19 Apr 2021
Topic Review
Real-Time Biomechanical Feedback Systems in Sport and Rehabilitation
Biomechanical feedback (BMF) is a treatment and body control method that uses sensors to measure a person’s physiological and physical body functions, parameters, and activities, including the ones that cannot be perceived by the human senses.
  • 2.3K
  • 12 Jul 2022
Topic Review
Annealing (Metallurgy)
In metallurgy and materials science, annealing is a heat treatment that alters the physical and sometimes chemical properties of a material to increase its ductility and reduce its hardness, making it more workable. It involves heating a material above its recrystallization temperature, maintaining a suitable temperature for an appropriate amount of time and then cooling. In annealing, atoms migrate in the crystal lattice and the number of dislocations decreases, leading to a change in ductility and hardness. As the material cools it recrystallizes. For many alloys, including carbon steel, the crystal grain size and phase composition, which ultimately determine the material properties, are dependent on the heating rate and cooling rate. Hot working or cold working after the annealing process alters the metal structure, so further heat treatments may be used to achieve the properties required. With knowledge of the composition and phase diagram, heat treatment can be used to adjust from harder and more brittle to softer and more ductile. In the case of ferrous metals, such as steel, annealing is performed by heating the material (generally until glowing) for a while and then slowly letting it cool to room temperature in still air. Copper, silver and brass can be either cooled slowly in air, or quickly by quenching in water. In this fashion, the metal is softened and prepared for further work such as shaping, stamping, or forming.
  • 2.3K
  • 09 Oct 2022
Topic Review
Bioleaching
In bioleaching, the function of the solvent is performed by microorganisms, by the action of either bacteria or fungi, as they participate in the biogeochemical cycle of minerals in direct ways by the metabolism of the microorganisms or indirectly by the products of their metabolism. Therefore, bioleaching is defined as the solubilization of metals from insoluble solid substrates.
  • 2.3K
  • 18 Jul 2023
Topic Review
Indoor Positioning System
The indoor positioning system (IPS) provides continuous real-time localization of objects or people within an enclosed space in different environments, using a network of transmitters and receivers. Indoor localization is more complex than outdoor localization because the indoor communication channel varies significantly with the environment and depends heavily on many factors, such as building structure, room layout, and construction materials.
  • 2.3K
  • 16 Dec 2022
Topic Review
Usain Bolt
Usain Bolt is a Jamaican sprinter widely regarded as the fastest human in history, holding world records in the 100 meters and 200 meters sprints. Known for his unprecedented speed, charismatic personality, and multiple Olympic gold medals, Bolt revolutionized athletics by setting new performance standards and inspiring a global audience.
  • 2.3K
  • 20 May 2025
Topic Review
Acoustic Emissions in Crack Detection
Acoustic emissions (AE) are becoming an important tool for hydraulic turbine failure detection and troubleshooting. In particular, artificial intelligence is a promising signal analysis research hotspot, and it has a great potential in the condition monitoring of hydraulic turbines using acoustic emissions as a key factor in the digitalisation process. 
  • 2.3K
  • 01 Mar 2024
Topic Review
Poplar-Type Propolis
Propolis is a resinous mixture, made by the honeybees from substances collected from tree or other plant buds, plant exudates, or resins found in the stem, branches, or leaves of different plants. 
  • 2.3K
  • 18 Jan 2021
Topic Review
List of Numerical Analysis Software
Listed here are end-user computer applications intended for use with numerical or data analysis:
  • 2.3K
  • 17 Oct 2022
Topic Review
Informal Sector Employment and Economic Growth
Originating in the context of third-world countries, the informal sector constitutes a dominant part of the economy and is identified as an untapped reservoir of opportunities in terms of employment and the entrepreneurial capabilities of developing countries; it is often called the subordinate zone of the overall economy that can play a significant role in the growth and socio-economic development of countries across the world. The informal sector accounts for almost half of the economic activities in developing countries. These activities were initially backed by the core assumptions of the classical theory that the informal economy would wither away after achieving persistent growth. However, the new view of the informal economy features it as contemporary growth that should proceed as a result of the changed economic context of countries. The prevalent feature of the informal economy around the globe provides support to the new view of informality, mentioned as a dichotomist’s approach, which indicates that the informal economy will not wither away; rather, it will be contested in an arrangement of interdependent coexistence with distinctively different conditions, notably in terms of employment arrangements.
  • 2.3K
  • 19 Oct 2022
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