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Topic Review
Titanium Aluminides
Titanium aluminides (TiAl) have the potential of substituting nickel-based superalloys (NBSAs) in the aerospace industries owing to their lightweight, good mechanical and oxidation properties. Functional simplicity, control of sintering parameters, exceptional sintering speeds, high reproducibility, consistency and safety are the main benefits of spark plasma sintering (SPS) over conventional methods. Though TiAl exhibit excellent high temperature properties, SPS has been employed to improve on the poor ductility at room temperature. Powder metallurgical processing techniques used to promote the formation of refined, homogeneous and contaminant-free structures, favouring improvements in ductility and other properties are discussed. This article further reviews published work on phase constituents, microstructures, alloy developments and mechanical properties of TiAl alloys produced by SPS. Finally, an overview of challenges in as far as the implementation of TiAl in industries of interest are highlighted.
  • 3.1K
  • 07 Jan 2021
Topic Review
Apocarotenoids
Carotenoid-derived apocarotenoids (CDCs) are formed by the oxidative cleavage of carbon–carbon double bonds in the carotenoid backbones either by carotenoid cleavage enzymes (CCDs) or via the exposure of carotenoids to ROS. Many of these apocarotenoids play key regulatory roles in plant development as growth simulators and inhibitors, signalling molecules, including as abscisic acid  and strigolactones, and have roles in plant defence against pathogens and herbivores. Others act as flavour and aroma compounds in fruit pericarp, flowers and seeds. The diverse variety of carotenoids (+700) means that the potential apocarotenoid products represent a significant number of natural compounds.
  • 3.1K
  • 03 Nov 2021
Topic Review
Rice Industry Value Chain and by-products valorization
The quantity of organic waste generated by agricultural sectors is continually increasing due to population growth and rising food demand. Rice is the primary consumable food in Asia. However, many stakeholders follow a linear economic model such as the “take–make–waste” concept. This linear model leads to a substantial environmental burden and the destruction of valuable resources without gaining their actual value. Because these by-products can be converted into energy generating and storage materials, and into bio-based products by cascading transformation processes within the circular economy concept, waste should be considered a central material.
  • 3.1K
  • 18 Apr 2023
Topic Review
Composting Technology of Brewer's Grains
The brewing industry is characterized by the large production of by-products. Following the fundamentals of a circular economy, several attempts to recycle brewers’ spent grain (BSG) have been investigated. However, little information is available on its use for composting.
  • 3.1K
  • 13 Jan 2021
Topic Review
Influence of Mindfulness on Men’s Sexual Activity
Mindfulness practice and mindfulness-based interventions are widely known, especially for women’s sexuality. The practice of mindfulness favours different variables of male sexuality, such as satisfaction and sexual functioning or genital self-image. Mindfulness-based interventions represent a valuable and promising contribution.
  • 3.1K
  • 06 Mar 2023
Topic Review
Byproduct Oxygen for Green Hydrogen Electrolysis
Water electrolysis for hydrogen production with renewable electricity is regularly studied. The inclusion of byproduct electrolytic oxygen capture and sale is of interest for parallel decarbonisation efforts elsewhere in the industry and could contribute to reducing green hydrogen costs. A deterministic hydrogen electrolysis system model is constructed to compare oxygen inclusion/exclusion scenarios. This uses wind and solar-PV electricity generation timeseries, a power-dependent electrolysis model to determine the energy efficiency of gas yield, and power allocation for gas post-processing energy within each hourly timestep. This maintains a fully renewable (and therefore low/zero carbon) electricity source for electrolysis and gas post-processing. The model is validated (excluding oxygen) against an existing low-cost GW-scale solar-hydrogen production scenario and an existing hydrogen production costs study with offshore wind generation at the multi-MW scale. For both comparisons, oxygen inclusion is then evaluated to demonstrate both the benefits and drawbacks of capture and utilisation, for different scenario conditions, and high parameter sensitivity can be seen regarding the price of renewable electricity.
  • 3.1K
  • 18 Jan 2024
Topic Review
Field
In physics, a field is a physical quantity, represented by a scalar, vector, or tensor, that has a value for each point in space and time. For example, on a weather map, the surface temperature is described by assigning a number to each point on the map; the temperature can be considered at a certain point in time or over some interval of time, to study the dynamics of temperature change. A surface wind map, assigning an arrow to each point on a map that describes the wind speed and direction at that point, is an example of a vector field, i.e. a 1-dimensional (rank-1) tensor field. Field theories, mathematical descriptions of how field values change in space and time, are ubiquitous in physics. For instance, the electric field is another rank-1 tensor field, while electrodynamics can be formulated in terms of two interacting vector fields at each point in spacetime, or as a single-rank 2-tensor field. In the modern framework of the quantum theory of fields, even without referring to a test particle, a field occupies space, contains energy, and its presence precludes a classical "true vacuum". This has led physicists to consider electromagnetic fields to be a physical entity, making the field concept a supporting paradigm of the edifice of modern physics. "The fact that the electromagnetic field can possess momentum and energy makes it very real ... a particle makes a field, and a field acts on another particle, and the field has such familiar properties as energy content and momentum, just as particles can have." In practice, the strength of most fields diminishes with distance, eventually becoming undetectable. For instance the strength of many relevant classical fields, such as the gravitational field in Newton's theory of gravity or the electrostatic field in classical electromagnetism, is inversely proportional to the square of the distance from the source (i.e., they follow Gauss's law). A field can be classified as a scalar field, a vector field, a spinor field or a tensor field according to whether the represented physical quantity is a scalar, a vector, a spinor, or a tensor, respectively. A field has a consistent tensorial character wherever it is defined: i.e. a field cannot be a scalar field somewhere and a vector field somewhere else. For example, the Newtonian gravitational field is a vector field: specifying its value at a point in spacetime requires three numbers, the components of the gravitational field vector at that point. Moreover, within each category (scalar, vector, tensor), a field can be either a classical field or a quantum field, depending on whether it is characterized by numbers or quantum operators respectively. In this theory an equivalent representation of field is a field particle, for instance a boson.
  • 3.1K
  • 11 Oct 2022
Topic Review
List of Years in Home Video
This page indexes the individual year in home video pages. Some years are annotated with a significant event as a reference point.
  • 3.1K
  • 21 Oct 2022
Topic Review
Global Navigation Satellite System, Datums and Mapping Accuracy
Current Global Navigation Satellite System (GNSS)-based geodetic techniques allow up to millimeter accuracy in positioning to be achieved globally, and high-precision mass-market positioning is becoming available to an accuracy of 5–10 cm.
  • 3.1K
  • 12 Oct 2023
Topic Review
Cardiac Glycosides
Cardiac glycosides (CG’s) are naturally occurring biologically active small molecules, used to diagnose a diversity of heart diseases such as congestive heart failure and cardiac arrhythmia. The story of CG’s started over 100 years ago when Sir William Withering reported the use of foxglove plant for treating “dropsy” associated with congestive heart failure and the foxglove plant (Digitalis purpurea) was still in the use for the extraction of Digoxin, a cardiac glycoside used to treat congestive heart failures (Johnson., 2012). The core structure of CGs comprises a steroid nucleus attached to a five-membered lactone ring (cardenolide) or six-membered lactone rings (bufadienolides) along with sugar moieties. Major plant-derived CGs were obtained from plant families of Apocynaceae, Scrophulariaceae, and Asparagaceae (Thevitia neriifolia, Neerium oleander, Digitalis purpurea, Digitalis lanata, Urginea maritime, and Strophanthus kombe). Structurally, all these contain a core steroid nucleus connected with sugar moiety at C3 position and lactone moiety at C17 position (Figure 1.3). The pharmacological significance of all the CG’s lies in the core steroid confirmation that contains A/B and C/D cis- portions and the properties such as pharmacokinetics and pharmacodynamics lie between the confined sugars molecules (Pongrakhananon., 2013). Apart from the plant sources, CG’s were also isolated from several animal species such as bufadienolide was isolated from frogs, and also mammalian tissues contain a cardiac glycoside which is similar to endogenous digitalis (Melero et al., 2000). Quite a few studies have conveyed that the human body does contain a lot more CG’s in different parts. For example, the plasma membrane contains Ouabain and Proscillaridin A and human urine contains digoxin and marinobufagenin whereas human lenses consist of 19-norbufalin (Schoner and Scheiner-Bobis., 2007). In the year 1785, William Withering was the first person to use a digitalis compound from Digitalis purpurea to treat congestive heart failures. Currently, Digoxin is used for treating congestive heart failures. The mechanism of action of Digoxin is that it can inhibit the sodium-potassium pump (Na+/K+-ATPase). Living organisms maintain more percentage of K+ within the cell and less percentage of Na+. However, the scenario at the outside of the cell is quite opposite to the intracellular conditions where a high percentage of Na+ and less percentage of K+ will be maintained. Hence, there is a concentration incline that exists between the outside and inside cellular environments, which will be maintained by sodium-potassium pump. The Na+/K+-ATPase is recognized as a transmembrane protein whose functions are to maintain ionic balance in the heart tissue. Na+/K+-ATPase utilizes ATP as the whole energy source, to exchange two K+ ions inside the cell and pushes three Na+ ions outside to maintain intra cellular homeostasis. Also, Na+/K+-ATPase transports glucose and amino acids by keeping less concentration of Na+ within the cell and helps in the maintenance of electrochemical incline. The increment of the Na+ level inside the cell retort to CGs fortifies the ion exchange mechanism. This leads to the expansion of intracellular Ca2+ percentage which therefore promotes organelle instances such as myocardial contractibility, and generates optimistic inotropic effects in the heart cell with CGs (Kaplan., 2002).  
  • 3.1K
  • 12 Aug 2020
Topic Review
Continuum Robots for Medical Applications
Traditional rigid robot application in the medical field is limited due to the limited degrees of freedom caused by their material and structure. Inspired by trunk, tentacles, and snakes, continuum robot (CR) could traverse confined space, manipulate objects in complex environment, and conform to curvilinear paths in space. The continuum robot has broad prospect in surgery due to its high dexterity, which can reach circuitous areas of the body and perform precision surgery. Recently, many efforts have been done by researchers to improve the design and actuation methods of continuum robots. Several continuum robots have been applied in clinic surgical interventions and demonstrated superiorities to conventional rigid-link robots.
  • 3.1K
  • 13 Jan 2021
Topic Review
Grape Phenolics
Grapes are rich in primary and secondary metabolites. Among the secondary metabolites, polyphenolic compounds are the most abundant in grape berries. Besides their important impacts on grape and wine quality, this class of compounds has beneficial effects on human health. Due to their antioxidant activity, polyphenols and phenolic acids can act as anti-inflammatory and anticancerogenic agents, and can modulate the immune system. In grape berries, polyphenols and phenolic acids can be located in the pericarp and seeds, but distribution differs considerably among these tissues. Although some classes of polyphenols and phenolic acids are under strict genetic control, the final content is highly influenced by environmental factors, such as climate, soil, vineyard, and management. 
  • 3.1K
  • 13 Jan 2021
Topic Review
Perfume and Flavor Engineering
The Perfumery Ternary Diagram enables us to determine the dominant odor for each perfume composition.
  • 3.1K
  • 29 Jun 2021
Topic Review
Sleep Paralysis and Lucid Dreaming
Sleep paralysis and lucid dreams are two states of consciousness that are connected to rapid eye movement (REM) sleep but are defined by higher awareness in contrast to regular REM sleep. Despite these similarities, the two states differ widely in their emotional tone and their perceived controllability.
  • 3.1K
  • 23 May 2023
Topic Review
Coumarin-Based Profluorescent and Fluorescent Substrates
Activities of xenobiotic-metabolizing enzymes have been measured with various in vitro and in vivo methods, such as spectrophotometric, fluorometric, mass spectrometric and radioactivity-based techniques. In fluorescence-based assays, the reaction produces a fluorescent product from a nonfluorescent substrate or vice versa. We describe here historical highlights and current use of (pro)fluorescent coumarin derivatives in evaluating activities of the major types of xenobiotic-metabolizing enzyme systems. Traditionally coumarin substrates have been used to measure oxidative activities of cytochrome P450 (CYP) enzymes. For this purpose, profluorescent coumarins are very sensitive, but generally lack selectivity for individual CYP forms. The entry describes several new coumarin-based substrates for measuring activities of CYP and conjugating enzymes with improved selectivity.
  • 3.1K
  • 14 Jul 2020
Topic Review
Windows 9X
Windows 9x is a generic term referring to a series of Microsoft Windows computer operating systems produced from 1995 to 2000, which were based on the Windows 95 kernel and its underlying foundation of MS-DOS, both of which were updated in subsequent versions. The first version in the 9x series was Windows 95, which was succeeded by Windows 98 and then Windows Me, which was the third and last version of Windows on the 9x line, until the series was superseded by Windows XP. Windows 9x is predominantly known for its use in home desktops. In 1998, Windows made up 82% of operating system market share. Internal release versions for versions of Windows 9x are 4.x. The internal versions for Windows 95, 98, and Me are 4.0, 4.1, and 4.9, respectively. Previous MS-DOS-based versions of Windows used version numbers of 3.2 or lower. Windows NT, which was aimed at professional users such as networks and businesses, used a similar but separate version number between 3.1 and 4.0. All versions of Windows from Windows XP onwards are based on the Windows NT codebase.
  • 3.1K
  • 30 Nov 2022
Topic Review
Analysis of Point Machines and Monitoring Systems
Point machines are the actuators for railway switching and crossing systems that guide trains from one track to another. Hence, the safe and reliable behavior of point machines are pivotal for rail transportation. Scholars and researchers have attempted to deploy various kinds of sensors on point machines for anomaly detection and/or incipient fault detection using date-driven algorithms. However, challenges arise when deploying condition monitoring and fault detection to trackside point machines in practical applications. 
  • 3.1K
  • 25 Oct 2023
Topic Review
Metastatic Dissemination in Lung Carcinogenesis
The tumor microenvironment plays a key role in the progression of lung tumorigenesis, progression, and metastasis. Recent data reveal that disseminated tumor cells (DTCs) appear to play a key role in the development and progression of lung neoplasiaby driving immune system dysfunction and established immunosuppression, which is vital for evading the host immune response.
  • 3.1K
  • 11 Aug 2022
Topic Review
Anthocyanins and Vibrant Color Pigments
Anthocyanins are water-soluble vacuolar pigments that occur ubiquitously in the plant kingdom, and they are widely distributed in fruits and vegetables as glycosides, having different sugars, such as glucose, rhamnose, xylose or arabinose, attached to an aglycon nucleus. Till now have been shown to have antioxidant properties in vitro and in vivo.  This work aim to provide an up-to-date overview regarding anthocyanins as functional molecules and their chemopreventive effects on melanoma in vitro and in vivo as well as a comprehensive description of major sources of anthocyanins. Until today, numerous studies evaluated the topic of anthocyanins and various types of cancer, regarding the anthocyanins’ preventative and inhibitory effects, underlying molecular mechanisms, and such. However, there is no targeted review available regarding the anticarcinogenic effects of dietary anthocyanins on skin cancers. If diagnosed at the early stages, the survival rate of skin cancer is quite high. Nevertheless, the metastatic form has a short prognosis. In fact, the incidence of melanoma skin cancer, the type with high mortality, has increased exponentially over the last 30 years, causing the majority of skin cancer deaths. Malignant melanoma is considered a highly destructive type of skin cancer due to its particular capacity to grow and spread faster than any other type of cancers. Plants, in general, have been used in disease treatment for a long time, and medicinal plants are commonly a part of anticancer drugs on the market.
  • 3.1K
  • 23 Sep 2020
Topic Review
Glucosinolates
Glucosinolates (GSLs) are secondary plant metabolites abundantly found in plant order Brassicales. GSLs are constituted by an S-β-d-glucopyrano unit anomerically connected to O-sulfated (Z)-thiohydroximate moiety. The side-chain of the O-sulfate thiohydroximate moiety, which is derived from a different amino acid, contributes to the diversity of natural GSL, with more than 130 structures identified and validated to this day. Both the structural diversity of GSL and their biological implication in plants have been biochemically studied. While intact GSLs are biologically inactive, various products, including isothiocyanates, nitriles, epithionitriles, and cyanides obtained through enzyme-catalyzed hydrolysis of GSLs, exhibit many different biological activities, among which several therapeutic benefits have been suggested. 
  • 3.1K
  • 12 Oct 2020
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