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Topic Review
Naturally Occurring Hydroxycinnamic Acids
Naturally occurring hydroxycinnamic acids, namely ferulic, para-coumaric, caffeic, sinapic acids, and 3,4-dimethoxycinnamic acid are present in significant quantities in the cell wall of plants. They can make up about a third of the phenolic compounds in our diet, hence the interest in their potential biological activity and properties. Methods of synthesis and properties of natural and synthetic hydroxycinnamic acid derivatives are reviewed in detail.
  • 3.9K
  • 10 Nov 2020
Topic Review
Applications of VR
Applications of VR (also known as virtual reality) can be found in fields as diverse as entertainment, marketing, education, medicine, and many others. They provide numerous possibilities for users to explore virtual realities for various purposes.
  • 3.9K
  • 01 Dec 2022
Topic Review
Classification of Solid Oxide Fuel Cells
Solid oxide fuel cells (SOFC) are promising, environmentally friendly energy sources. Many works are devoted to the study of materials, individual aspects of SOFC operation, and the development of devices based on them. This entry attempts to cover and structure the entire spectrum of SOFC concepts and designs that currently exist.
  • 3.9K
  • 13 Apr 2022
Topic Review
Eco-efficiency
The term eco-efficiency was first proposed in 1990 by Schaltegger and Sturm. However, it was in 1991 that the World Business Council for Sustainable Development (WBCSD) was responsible for introducing one of the main concepts of eco-efficiency to the world. The term was defined as the delivery of economically competitive goods and services that meet the needs of society in terms of quality of life and that the entire process of manufacturing and availability for consumption, that is, throughout its life cycle, should have the least possible impact on the environment.
  • 3.9K
  • 13 Dec 2021
Topic Review
Philosophy of Baruch Spinoza
Baruch Spinoza's philosophy encompasses nearly every area of philosophical discourse, including metaphysics, epistemology, political philosophy, ethics, philosophy of mind, and philosophy of science. It earned Spinoza an enduring reputation as one of the most important and original thinkers of the seventeenth century. Samuel Shirley, who translated Spinoza's complete works into English, summed up the significance of Spinoza's philosophy as follows: Spinoza's philosophy is largely contained in two books: the Theologico-Political Treatise, and the Ethics. The former was published during his lifetime, but the latter, which contains the entirety of his philosophical system in its most rigorous form, was not published until after his death in 1677. The rest of the writings we have from Spinoza are either earlier, or incomplete, works expressing thoughts that were crystallized in the two aforementioned books (e.g., the Short Treatise and the Treatise on the Emendation of the Intellect), or else they are not directly concerned with Spinoza's own philosophy (e.g., The Principles of Cartesian Philosophy and The Hebrew Grammar). He also left behind many letters that help to illuminate his ideas and provide some insight into what may have been motivating his views.
  • 3.9K
  • 24 Nov 2022
Topic Review
Penguin Visual System
Penguins require vision that is adequate for both subaerial and submarine environments under a wide range of illumination. Amphibious vision is facilitated by a relatively flat cornea, the power in air varying from 10.2 dioptres (D) to 41.3 D depending on the species, and there is good evidence for emmetropia both above and below water. All penguins are trichromats with loss of rhodopsin 2, a nocturnal feature, but only deeper diving penguins have been noted to have pale oil droplets and a preponderance of rods. Conversely, the diurnal, shallow-diving little penguin has a higher ganglion cell density (28,867 cells/mm2) and f-number (3.5) than those that operate in dimmer light. In most species studied, there is some binocular overlap, but this reduces upon submergence.
  • 3.9K
  • 09 Feb 2023
Topic Review
Coenzyme A
Coenzyme A (CoA) is synthetized from pantothenic acid (commonly known as vitamin B5). The importance of CoA as a carrier of acyl residues in cell metabolism is well understood. Coenzyme A participates in more than 100 different catabolic and anabolic reactions, including those involved in the metabolism of lipids, carbohydrates, proteins, ethanol, bile acids, and xenobiotics.
  • 3.9K
  • 15 Dec 2020
Topic Review
Legendary Salamander in Popular Culture
References to the legendary salamander in popular culture—in fiction (especially fantasy fiction), games, animation, and so on—can be categorized in three ways: as a fantastic (sometimes magical) beast with an affinity with fire, as a true fire elemental, and allusions to the salamander's fiery nature.
  • 3.9K
  • 28 Nov 2022
Topic Review
Liposomes for Drug Delivery and Their Production Methods
Liposomes are well-known nanoparticles with a non-toxic nature and the ability to incorporate both hydrophilic and hydrophobic drugs simultaneously. As modern drug delivery formulations are produced by emerging technologies, numerous advantages of liposomal drug delivery systems over conventional liposomes or free drug treatment of cancer have been reported.
  • 3.9K
  • 17 Nov 2022
Topic Review
Monotremata
Monotremes (/ˈmɒnətriːmz/) are prototherian mammals of the order Monotremata. They are one of the three groups of living mammals, along with placentals (Eutheria) and marsupials (Metatheria). Monotremes are typified by structural differences in their brains, jaws, digestive tract, reproductive tract, and other body parts compared to the more common mammalian types. In addition, they lay eggs rather than bearing live young, but, like all mammals, the female monotremes nurse their young with milk. Monotremes have been considered members of Australosphenida, a clade which contains extinct mammals from the Jurassic and Cretaceous of Madagascar, South America and Australia, though this is disputed. The only surviving examples of monotremes are all indigenous to Australia and New Guinea although there is evidence that they were once more widespread, as Monotrematum is known from the Paleocene of South America. The extant monotreme species are the platypus and four species of echidnas. There is currently some debate regarding monotreme taxonomy. The name monotreme derives from the Greek words μονός (monós 'single') and τρῆμα (trêma 'hole'), referring to the cloaca.
  • 3.9K
  • 19 Oct 2022
Topic Review Peer Reviewed
Aircraft Icing Severity Evaluation
Aircraft icing refers to the ice buildup on the surface of an aircraft flying in icing conditions. The ice accretion on the aircraft alters the original aerodynamic configuration and degrades the aerodynamic performances and may lead to unsafe flight conditions. Evaluating the flow structure, icing mechanism and consequences is of great importance to the development of an anti/deicing technique. Studies have shown computational fluid dynamics (CFD) and machine learning (ML) to be effective in predicting the ice shape and icing severity under different flight conditions. CFD solves a set of partial differential equations to obtain the air flow fields, water droplets trajectories and ice shape. ML is a branch of artificial intelligence and, based on the data, the self-improved computer algorithms can be effective in finding the nonlinear mapping relationship between the input flight conditions and the output aircraft icing severity features.
  • 3.9K
  • 13 Apr 2022
Topic Review
Capital Centre
The Capital Centre (later USAir Arena and US Airways Arena) was an indoor arena in the eastern United States, located in Landover, Maryland, east of Washington, D.C. Opened in late 1973, it closed in 1999, and was demolished in 2002. The seating capacity was 18,756 for basketball and 18,130 for hockey. The elevation at street level was approximately 160 feet (50 m) above sea level. The U.S. Census Bureau defined the land, later occupied by The Boulevard at the Capital Centre, as being in the Mitchellville census-designated place as of the 1990 U.S. Census, while in the 2000 U.S. Census the area was placed in the Lake Arbor CDP.
  • 3.9K
  • 28 Nov 2022
Topic Review
Bladder Cancer Biomarkers
The high occurrence of bladder cancer and its tendency to recur combined with lifelong surveillance make the treatment of superficial bladder cancer one of the most expensive and time-consuming. Moreover, carcinoma in situ often leads to muscle invasion with an unfavourable prognosis. Currently, invasive methods including cystoscopy and cytology remain a gold standard. The aim is to find biomarkers with the best specificity and sensitivity, allowing the treatment plan to optimise and have potential applications in clinical practice. Such non-invasive methods can be measure in human body fluids, for example, urine or serum: Cytokeratin fragments (CYFRA 21.1), Excision Repair Cross-Complementation 1 (ERCC1), Tumour Protein p53 (Tp53), Fibroblast Growth Factor Receptor 3 (FGFR3), Tumor-Associated Trypsin Inhibitor (TATI).
  • 3.9K
  • 29 Mar 2022
Topic Review
Fused 1,5-naphthyridines
Heterocyclic nitrogen compounds, including fused 1,5-naphthyridines, have versatile applications in synthetic organic chemistry and play an important role in the field of medicinal chemistry, as many of them have a wide range of biological activities. In this review, a wide range of synthetic protocols for the construction of this scaffold are presented. For example, Friedländer, Skraup, Semmlere-Wolff, and hetero-Diels-Alder, among others, are well known classical synthetic protocols used for the construction of the main 1,5-naphthyridine scaffold. These syntheses are classified according to the nature of the cycle fused to the 1,5-naphthyridine ring: carbocycles, nitrogen heterocycles, oxygen heterocycles, and sulphur heterocycles. In addition, taking into account the aforementioned versatility of these heterocycles, their reactivity is presented as well as their use as a ligand for metal complexes formation. Finally, those fused 1,5-naphthyridines that present biological activity and optical applications, among others, are indicated.
  • 3.9K
  • 31 Aug 2020
Topic Review
Aerogel-Based Plasters
Aerogel has entered the construction field in the last two decades as a component of many insulation products, due to its high thermal performance. Aerogel-based plasters allow the matching of high thermal performance and limited thickness. This makes them suitable when retrofitting an existing building and also when restoring a heritage building. This entry presents the state of the art of the research on aerogel-based plasters as a part of the aerogel-products for the building sector.
  • 3.9K
  • 08 Dec 2020
Topic Review
Market Power
In economics, market power refers to the ability of a firm to influence the price at which it sells a product or service to increase economic profit. In other words, market power occurs if a firm does not face a perfectly elastic demand curve and can set its price (P) above marginal cost (MC) without losing sales. This indicates that the magnitude of market power is associated with the gap between P and MC at a firm's profit maximising level of output. Such propensities contradict perfectly competitive markets, where market participants have no market power, P = MC and firms earn zero economic profit. Market participants in perfectly competitive markets are consequently referred to as 'price takers', whereas market participants that exhibit market power are referred to as 'price makers' or 'price setters'. A firm with market power has the ability to individually affect either the total quantity or price in the market. This said, market power has been seen to exert more upward pressure on prices due to effects relating to Nash equilibria and profitable deviations that can be made by raising prices. Price makers face a downward-sloping demand curve and as a result, price increases lead to a lower quantity demanded. The decrease in supply creates an economic deadweight loss (DWL) and a decline in consumer surplus. This is viewed as socially undesirable and has implications for welfare and resource allocation as larger firms with high markups negatively effect labour markets by providing lower wages. Perfectly competitive markets do not exhibit such issues as firms set prices that reflect costs, which is to the benefit of the customer. As a result, many countries have antitrust or other legislation intended to limit the ability of firms to accrue market power. Such legislation often regulates mergers and sometimes introduces a judicial power to compel divestiture. Market power provides firms with the ability to engage in unilateral anti-competitive behavior. As a result, legislation recognises that firms with market power can, in some circumstances, damage the competitive process. In particular, firms with market power are accused of limit pricing, predatory pricing, holding excess capacity and strategic bundling. A firm usually has market power by having a high market share although this alone is not sufficient to establish the possession of significant market power. This is because highly concentrated markets may be contestable if there are no barriers to entry or exit. Invariably, this limits the incumbent firm's ability to raise its price above competitive levels. If no individual participant in the market has significant market power, anti-competitive conduct can only take place through collusion, or the exercise of a group of participants' collective market power. An example of which was seen in 2007, when British Airways was found to have colluded with Virgin Atlantic between 2004 and 2006, increasing their surcharges per ticket from £5 to £60. Regulators are able to assess the level of market power and dominance a firm has and measure competition through the use of several tools and indicators. Although market power is extremely difficult to measure, through the use of widely used analytical techniques such as concentration ratios, the Herfindahl-Hirschman index and the Lerner index, regulators are able to oversee and attempt to restore market competitiveness.
  • 3.9K
  • 19 Oct 2022
Topic Review
Entity–Component–System
Entity–component–system (ECS) is an architectural pattern that is mostly used in game development. ECS follows the composition over inheritance principle that allows greater flexibility in defining entities where every object in a game's scene is an entity (e.g. enemies, bullets, vehicles, etc.). Every Entity consists of one or more components which add behavior or functionality. Therefore, the behavior of an entity can be changed at runtime by adding or removing components. This eliminates the ambiguity problems of deep and wide inheritance hierarchies that are difficult to understand, maintain and extend. Common ECS approaches are highly compatible and often combined with data-oriented design techniques.
  • 3.9K
  • 23 Nov 2022
Topic Review
Magnetoelectric Sensors
Multiferroic magnetoelectric (ME) materials with the capability of coupling magnetization and electric polarization have been providing diverse routes towards functional devices and thus attracting ever-increasing attention. The typical device applications include sensors, energy harvesters, magnetoelectric random access memories, tunable microwave devices and ME antennas etc. Among those application scenarios, ME sensors are specifically focused in this review article. We begin with an introduction of materials development and then recent advances in ME sensors are overviewed. Engineering applications of ME sensors are followed and typical scenarios are presented. Finally, several remaining challenges and future directions from the perspective of sensor designs and real applications are included.
  • 3.9K
  • 07 Jun 2021
Topic Review
Stereolithography
Being the earliest form of Additive manufacturing, Stereolithography (SLA) fabricates 3D objects by selectively solidifying the liquid resin through photopolymerization reaction. The ability to fabricate objects with high accuracy as well as a wide variety of materials brings much attention to stereolithography. Since its invention in 1980s, SLA underwent four generations of major technological innovation over the past 40 years. These innovations have thus result in a diversifies range of stereolithography systems with dramatically improved resolution, throughput, and materials selection for creating complex 3D objects and devices. In this paper, we review the four generations stereolithography processes, which are scanning, projection, continuous and volumetric stereolithography. For each generation, representative stereolithography system configurations are also discussed in detail. In addition, other derivative technologies, such as scanning-projection, multi-material, and magnetically assisted stereolithography processes, are also included in this review.
  • 3.9K
  • 16 Sep 2020
Topic Review Peer Reviewed
SEM-PLS Approach to Green Building
Green buildings refer to buildings that decrease adverse environmental effects and maintain natural resources. They can diminish energy consumption, greenhouse gas emissions, the usage of non-renewable materials, water consumption, and waste generation while improving occupants’ health and well-being. As such, several rating tools and benchmarks have been developed worldwide to assess green building performance (GBP), including the Building Research Establishment Environmental Assessment Method (BREEAM) in the United Kingdom, German Sustainable Building Council (DGNB), Leadership in Energy and Environmental Design (LEED) in the United States and Canada, Comprehensive Assessment System for Built Environment Efficiency (CASBEE) in Japan, Green Star in Australia, Green Mark in Singapore, and Green Building Index in Malaysia. Energy management (EM) during building operation could also improve GBP. One of the best approaches to evaluating the impact of EM on GBP is by using structural equation modelling (SEM). SEM is a commanding statistical method to model testing. One of the most used SEM variance-based approaches is partial least squares (PLS), which can be implemented in the SmartPLS application. PLS-SEM uses path coefficients to determine the strength and significance of the hypothesised relationships between the latent constructs. 
  • 3.9K
  • 13 Apr 2022
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