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Topic Review
Ionocraft
An ionocraft or ion-propelled aircraft (commonly known as a lifter or hexalifter) is a device that uses an electrical electrohydrodynamic (EHD) phenomenon to produce thrust in the air without requiring any combustion or moving parts. The term "ionocraft" dates back to the 1960s, an era in which EHD experiments were at their peak. In its basic form, it simply consists of two parallel conductive electrodes, one in the form of a fine wire and another which may be formed out of wire grid, tubes or foil skirts with a smooth round surface. When such an arrangement is powered by high voltage (in the range of a few kilovolts), it produces thrust. The ionocraft forms part of the EHD thruster family, but is a special case in which the ionisation and accelerating stages are combined into a single stage. The device is a popular science fair project for students. It is also popular among anti-gravity or so-called "electrogravitics" proponents, due to the research of Thomas Townsend Brown, who built these devices in the 1920s and incorrectly believed that he had found a way to modify gravity using electric fields. The term "lifter" is an accurate description because it is not an anti-gravity device; rather, it produces lift using the same basic principle as a rocket, i.e. from the equal but opposite force upward generated by the driving force downward, specifically by driving the ionized air downward in the case of the ionocraft. Much like a rocket or a jet engine (it can actually be much more thrust efficient than a jet engine), the force that an ionocraft generates is consistently oriented along its own axis, regardless of the surrounding gravitational field. Claims of the device also working in a vacuum have been disproved. Ionocraft require many safety precautions due to the high voltage required for their operation; nevertheless, a large subculture has grown up around this simple EHD thrusting device and its physics are now known to a much better extent.
  • 4.0K
  • 01 Dec 2022
Topic Review
Artificial Intelligence for Digital Heritage Innovation
Artificial intelligence (AI) is a game changer in many fields, including cultural heritage. It supports the planning and preservation of heritage sites and cities, enables the creation of virtual experiences to enrich cultural tourism and engagement, supports research, and increases access and understanding of heritage objects. Despite some impressive examples, the full potential of AI for economic, social, and cultural change is not yet fully visible.
  • 4.0K
  • 27 Feb 2024
Topic Review
Materials Used for Customized Healing Abutment
A customized healing abutment is designed by modifying the size and transmucosal shape of the healing abutment to mimic the natural profile of an emerging tooth. 
  • 4.0K
  • 22 Dec 2022
Topic Review
Memory Span
In psychology and neuroscience, memory span is the longest list of items that a person can repeat back in correct order immediately after presentation on 50% of all trials. Items may include words, numbers, or letters. The task is known as digit span when numbers are used. Memory span is a common measure of working memory and short-term memory. It is also a component of cognitive ability tests such as the WAIS. Backward memory span is a more challenging variation which involves recalling items in reverse order.
  • 4.0K
  • 20 Oct 2022
Topic Review
Pseudomonas aeruginosa
Pseudomonas aeruginosa is the most frequent cause of infection among non-fermenting Gram-negative bacteria, predominantly affecting immunocompromised patients, but its pathogenic role should not be disregarded in immunocompetent patients. seudomonas aeruginosa is the most frequent cause of infection among non-fermenting Gram-negative bacteria, predominantly affecting immunocompromised patients, but its pathogenic role should not be disregarded in immunocompetent patients.
  • 4.0K
  • 21 Jan 2021
Topic Review
Ballast Contamination Mechanisms
Ballasted railway tracks constitute the major transportation grids in many countries across the globe; they convey commuters, as well as freight and bulk cargoes, between cities, mines, farmlands, and ports . The railtrack structure can be categorised into two groups: the substructure and the superstructure. The substructure comprises the subgrade, the sub-ballast, and the ballast, while the superstructure encompasses the sleepers (timber or concrete), the fastening mechanism, and the steel rails.
  • 4.0K
  • 14 Jan 2021
Topic Review
Ramp Rate Limitation of Wind Power
A run for increasing the integration of renewable energy sources in the electricity network has been seen because of the big concern about environmental issues and pollution from controllable power units. Wind power is one of the most-used renewable energy sources, and the objective of limiting the ramp rate of the power output is to produce more stable power. The studies of ramp rate limitation applied in wind power production deal with the definition and detection of this phenomenon in the real data, the methodologies used to forecast it, its application for managing grids and microgrids, the different actions aimed at physically implementing the restriction, and some of the grid code requirements used in different nations.
  • 4.0K
  • 25 Oct 2022
Topic Review
MecA (Gene)
The mecA gene is a gene found in bacterial cells which allows a bacterium to be resistant to antibiotics such as methicillin, penicillin and other penicillin-like antibiotics. The most commonly known carrier of the mecA gene is the bacterium known as Methicillin-resistant Staphylococcus aureus (MRSA). In Staphylococcus species, mecA is spread on the SCCmec genetic element. Resistant strains are responsible for many infections originating in hospitals. The mecA gene does not allow the ringlike structure of penicillin-like antibiotics to bind to the enzymes that help form the cell wall of the bacterium (transpeptidases), and hence the bacteria is able to replicate as normal. mecA is located on the staphylococcal chromosome cassette mec. The gene encodes the protein PBP2A (penicillin binding protein 2A). PBP2A has a low affinity for beta-lactam antibiotics such as methicillin and penicillin. This enables transpeptidase activity in the presence of beta-lactams, preventing them from inhibiting cell wall synthesis.
  • 4.0K
  • 03 Nov 2022
Topic Review
Atomic Radii of the Elements (Data Page)
The atomic radius of a chemical element is the distance from the center of the nucleus to the outermost shell of an electron. Since the boundary is not a well-defined physical entity, there are various non-equivalent definitions of atomic radius. Depending on the definition, the term may apply only to isolated atoms, or also to atoms in condensed matter, covalently bound in molecules, or in ionized and excited states; and its value may be obtained through experimental measurements, or computed from theoretical models. Under some definitions, the value of the radius may depend on the atom's state and context. Atomic radii vary in a predictable and explicable manner across the periodic table. For instance, the radii generally decrease rightward along each period (row) of the table, from the alkali metals to the noble gases; and increase down each group (column). The radius increases sharply between the noble gas at the end of each period and the alkali metal at the beginning of the next period. These trends of the atomic radii (and of various other chemical and physical properties of the elements) can be explained by the electron shell theory of the atom; they provided important evidence for the development and confirmation of quantum theory.
  • 4.0K
  • 02 Dec 2022
Topic Review
Rabbit Meat Production
Rabbit meat could play an important role in health, the rural economy, and sustainable development. Rabbit meat has excellent nutritional features, such as high protein content, low-fat content, and a high percentage of unsaturated fatty acids, low cholesterol and sodium levels. In addition, rabbit meat production contributes to maintaining economic activities in rural marginal areas.
  • 4.0K
  • 10 Feb 2023
Topic Review
Friction Stir Processing
Friction stir processing (FSP) is a material processing technique developed in 1999 derived from friction stir welding (FSW). Developed by Mishra et al., this process utilizes localized plastic deformation by rotating a specialized pin through the working piece. 
  • 4.0K
  • 22 Sep 2021
Topic Review
Integration of Blockchain Technology with Cloud Computing
Blockchain technology’s desirable characteristics are decentralization, integrity, immutability, verification, fault tolerance, anonymity, audibility, and transparency. There are many benefits of blockchain technology concerning cloud computing, including those associated with business data handling, privacy, and encryption. 
  • 4.0K
  • 29 Nov 2022
Topic Review
Psychiatric Survivors Movement
The psychiatric survivors movement (more broadly consumer/survivor/ex-patient movement) is a diverse association of individuals who either currently access mental health services (known as consumers or service users), or who are survivors of interventions by psychiatry, or who are ex-patients of mental health services. The psychiatric survivors movement arose out of the civil rights movement of the late 1960s and early 1970s and the personal histories of psychiatric abuse experienced by some ex-patients. The key text in the intellectual development of the survivor movement, at least in the USA, was Judi Chamberlin's 1978 text, On Our Own: Patient Controlled Alternatives to the Mental Health System. Chamberlin was an ex-patient and co-founder of the Mental Patients' Liberation Front. Coalescing around the ex-patient newsletter Dendron, in late 1988 leaders from several of the main national and grassroots psychiatric survivor groups felt that an independent, human rights coalition focused on problems in the mental health system was needed. That year the Support Coalition International (SCI) was formed. SCI's first public action was to stage a counter-conference and protest in New York City , in May, 1990, at the same time as (and directly outside of) the American Psychiatric Association's annual meeting. In 2005 the SCI changed its name to MindFreedom International with David W. Oaks as its director. Common themes are "talking back to the power of psychiatry", rights protection and advocacy, and self-determination. While activists in the movement may share a collective identity to some extent, views range along a continuum from conservative to radical in relation to psychiatric treatment and levels of resistance or patienthood.
  • 4.0K
  • 23 Nov 2022
Topic Review
Glutamatergic System in Depression
Major depressive disorder (MDD) is a heterogeneous neuropsychological disorder characterized by a combination of symptoms that negatively impact the productivity and well-being of inflicted patients, including impairments in cognition, emotional regulation, memory, motor function, motivation, and possible suicidal ideation. Glutamate is the major excitatory neurotransmitter in the central nervous system. It plays an important role in several physiological functions.
  • 4.0K
  • 11 May 2022
Topic Review
Inner Core
The Earth's inner core is the Earth's innermost part. It is primarily a solid ball with a radius of about 1,220 kilometres (760 miles), which is about 70% of the Moon's radius. It is composed of an iron–nickel alloy and some other elements. The temperature at the inner core's surface is approximately 5,700 K (5,430 °C) or 9806 °F, which is about the temperature at the surface of the Sun.
  • 4.0K
  • 10 Nov 2022
Topic Review
Momo Challenge Hoax
The "Momo Challenge" was a hoax and an Internet urban legend about a nonexistent social media challenge that was spread on Facebook and other media outlets. It was reported that children and adolescents were being enticed by a user named Momo to perform a series of dangerous tasks including violent attacks, self-harm and suicide. Despite claims that the phenomenon had reached worldwide proportions in July 2018, the number of actual complaints was relatively small and no law enforcement agency has confirmed that anyone was harmed as a direct result of it. Concern and distress registered by children was primarily driven by media reports rather than as a result of "Momo", leading children's charities to view warnings against the alleged phenomenon as causing more harm than good by leading to a self-fulfilling prophecy which may encourage children to look up violent material on the Internet. The challenge was reported to become "a worldwide phenomenon" in 2018 after an Indonesian newspaper reported that it had caused a 12-year-old girl to kill herself. Awareness grew in February 2019 after the Police Service of Northern Ireland posted a public warning on Facebook, and American media personality Kim Kardashian posted on her Instagram Story pleading for YouTube to remove alleged "Momo" videos.
  • 4.0K
  • 01 Dec 2022
Topic Review
Cold Atmospheric Pressure Plasma Technology
Cold atmospheric pressure plasma (CAPP) technology has received substantial attention due to its valuable properties including operational simplicity, low running cost, and environmental friendliness. Several different gases (air, nitrogen, helium, argon) and techniques (corona discharge, dielectric barrier discharge, plasma jet) can be used to generate plasma at atmospheric pressure and low temperature. Plasma treatment is routinely used in materials science to modify the surface properties (e.g., wettability, chemical composition, adhesion) of a wide range of materials (e.g., polymers, textiles, metals, glasses). Moreover, CAPP seems to be a powerful tool for the inactivation of various pathogens (e.g., bacteria, fungi, viruses) in the food industry (e.g., food and packing material decontamination, shelf life extension), agriculture (e.g., disinfection of seeds, fertilizer, water, soil) and medicine (e.g., sterilization of medical equipment, implants). Plasma medicine also holds great promise for direct therapeutic treatments in dentistry (tooth bleaching), dermatology (atopic eczema, wound healing) and oncology (melanoma, glioblastoma).
  • 4.0K
  • 10 Jun 2021
Topic Review
Meaning
In semantics, semiotics, philosophy of language, metaphysics, and metasemantics, meaning "is a relationship between two sorts of things: signs and the kinds of things they intend, express, or signify". The types of meanings vary according to the types of the thing that is being represented. Namely: The major contemporary positions of meaning come under the following partial definitions of meaning:
  • 4.0K
  • 09 Oct 2022
Topic Review
Ionizing Radiation
The development of protective agents against harmful radiations has been a subject of investigation for decades. However, effective (ideal) radioprotectors and radiomitigators remain an unsolved problem. Because ionizing radiation-induced cellular damage is primarily attributed to free radicals, radical scavengers are promising as potential radioprotectors. Early development of such agents focused on thiol synthetic compounds, e.g., amifostine (2-(3-aminopropylamino) ethylsulfanylphosphonic acid), approved as a radioprotector by the Food and Drug Administration (FDA, USA) but for limited clinical indications and not for nonclinical uses. To date, no new chemical entity has been approved by the FDA as a radiation countermeasure for acute radiation syndrome (ARS). All FDA-approved radiation countermeasures (filgrastim, a recombinant DNA form of the naturally occurring granulocyte colony-stimulating factor, G-CSF; pegfilgrastim, a PEGylated form of the recombinant human G-CSF; sargramostim, a recombinant granulocyte macrophage colony-stimulating factor, GM-CSF) are classified as radiomitigators. No radioprotector that can be administered prior to exposure has been approved for ARS. This differentiates radioprotectors (reduce direct damage caused by radiation) and radiomitigators (minimize toxicity even after radiation has been delivered). Molecules under development with the aim of reaching clinical practice and other nonclinical applications are discussed. Assays to evaluate the biological effects of ionizing radiations are also analyzed. Ionizing radiation is the energy released by atoms in the form of electromagnetic waves (e.g., X or gamma rays) or particle radiation (alpha, beta, electrons, protons, neutrons, mesons, prions, and heavy ions) with sufficient energy to ionize atoms or molecules.
  • 4.0K
  • 23 Feb 2022
Topic Review
Melatonin: ATP Regulation in MLOs
Biomolecular condensates are membraneless organelles (MLOs) that form dynamic, chemically distinct subcellular compartments organizing macromolecules such as proteins, RNA, and DNA in unicellular prokaryotic bacteria and complex eukaryotic cells. Separated from surrounding environments, MLOs in the nucleoplasm, cytoplasm, and mitochondria assemble by liquid–liquid phase separation (LLPS) into transient, non-static, liquid-like droplets that regulate essential molecular functions. LLPS is primarily controlled by ATP-dependent post-translational modifications (PTMs) that fine-tune the balance between attractive and repulsive charge states and/or binding motifs of proteins. Aberrant phase separation due to the absence of adequate hydrotropic small molecules such as ATP can cause pathological protein aggregation in diseases such as neurodegenerative disorders. Melatonin is a potent antioxidant capable of protecting cardiolipin and membrane lipids raft domains from peroxidation to support ATPase functionality and ion channel activities that may exert a dominant influence over phase separation in biomolecular condensates during condensate coacervation or dissolution processes that are ATP-dependent. 
  • 4.0K
  • 30 Sep 2021
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