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Topic Review
Chemical Extraction of Chitosan from Shrimp Shells
The extraction of chitin and chitosan from raw shrimp wastes through three major processes: demineralization, deproteinization, and deacetylation. Chitin can be recovered from shrimp shells by removing minerals and proteins under diluted acidic and alkaline treatment, followed by a concentrated alkaline treatment to remove acetyl groups and obtain chitosan.
  • 6.3K
  • 01 Nov 2022
Topic Review
West African Lungfish (Protopterus spp.)
The west african lungfish refers to species of freshwater fishes in the genus Protopterus, belonging to the subclass Dipnoi. These fishes are notable for their unique ability to respire using both gills and lungs, a feature that has attracted considerable scientific attention due to its evolutionary significance. Native to various freshwater habitats across Africa, African lungfishes represent a lineage of sarcopterygian fishes with deep evolutionary connections to the origins of tetrapods.
  • 6.3K
  • 15 Sep 2025
Topic Review
Fruit Vinegar Production
The production of fruit vinegars as a way of making use of fruit by-products is an option widely used by the food industry, since surplus or second quality fruit can be used without compromising the quality of the final product. The acetic nature of vinegars and its subsequent impact on the organoleptic properties of the final product allows almost any type of fruit to be used for its elaboration.
  • 6.3K
  • 13 May 2021
Topic Review
Learning Styles
Learning styles refer to a range of competing and debunked theories that aim to account for differences in individuals' learning. Many theories share the proposition that humans can be classified according to their 'style' of learning, but differ in how the proposed styles should be defined, categorized and assessed.:8 A common concept is that individuals differ in how they learn.:266 The idea of individualized learning styles became popular in the 1970s, and has greatly influenced education despite the criticism that the idea has received from some researchers.:107–108 Proponents recommend that teachers have to run a needs analysis to assess the learning styles of their students and adapt their classroom methods to best fit each student's learning style. Although there is ample evidence that individuals express personal preferences for how they prefer to receive information,:108 few studies have found any validity in using learning styles in education.:267 Critics say there is no consistent evidence that identifying an individual student's learning style and teaching for specific learning styles produces better student outcomes.:33 Since 2012, Learning Styles have often been referred to as a "neuromyth" in education. There is evidence of empirical and pedagogical problems related to forcing learning tasks to "correspond to differences in a one-to-one fashion". Studies contradict the widespread "meshing hypothesis" that a student will learn best if taught in a method deemed appropriate for the student's learning style. However, a 2020 systematic review suggested that a majority (89%) of educators around the world continue to believe that the meshing hypothesis is correct. Studies further show that teachers cannot assess the learning style of their students accurately.
  • 6.3K
  • 02 Nov 2022
Topic Review
BeiDou Navigation Satellite System
The BeiDou Navigation Satellite System (BDS) is a Chinese satellite navigation system. It consists of two separate satellite constellations. The first BeiDou system, officially called the BeiDou Satellite Navigation Experimental System and also known as BeiDou-1, consists of three satellites which since 2000 has offered limited coverage and navigation services, mainly for users in China and neighboring regions. Beidou-1 was decommissioned at the end of 2012. The second generation of the system, officially called the BeiDou Navigation Satellite System (BDS) and also known as COMPASS or BeiDou-2, became operational in China in December 2011 with a partial constellation of 10 satellites in orbit. Since December 2012, it has been offering services to customers in the Asia-Pacific region. In 2015, China started the build-up of the third generation BeiDou system (BeiDou-3) in the global coverage constellation. The first BDS-3 satellite was launched on 30 March 2015. As of January 2018, nine BeiDou-3 satellites have been launched. BeiDou-3 will eventually consist of 35 satellites and is expected to provide global services upon completion in 2020. When fully completed, BeiDou will provide an alternative global navigation satellite system to the United States owned Global Positioning System (GPS), and is expected to be more accurate than the GPS. It was claimed in 2016 that BeiDou-3 will reach millimeter-level accuracy (with post-processing), which is ten times more accurate than the finest level of GPS. According to China Daily, in 2015, fifteen years after the satellite system was launched, it was generating a turnover of $31.5 billion per annum for major companies such as China Aerospace Science and Industry Corp, AutoNavi Holdings Ltd, and China North Industries Group Corp.
  • 6.3K
  • 29 Nov 2022
Topic Review
Vascular Endothelial Growth Factors
Vascular endothelial growth factors (VEGFs) are primary regulators of blood and lymphatic vessels. Hemangiogenic VEGFs (VEGF-A, PlGF, and VEGF-B) target mostly blood vessels, while the lymphangiogenic VEGFs (VEGF-C and VEGF-D) target mostly lymphatic vessels. Blocking VEGF-A is used today to treat several types of cancer (“antiangiogenic therapy”). However, in other diseases, it would be beneficial to do the opposite, namely to increase the activity of VEGFs. For example, VEGF-A could generate new blood vessels to protect from heart disease, and VEGF-C could generate new lymphatics to counteract lymphedema. Clinical trials that tried to stimulate blood vessel growth in ischemic diseases have been disappointing so far, and the first clinical trials targeting the lymphatic vasculature have progressed to phase II. Antiangiogenic drugs targeting VEGF-A such as bevacizumab or aflibercept neutralize the growth factor directly. However, since VEGF-C and VEGF-D are produced as inactive precursors, novel drugs against the lymphangiogenic VEGFs could also target the enzymatic activation of VEGF-C and VEGF-D. Because of the delicate balance between too much and too little vascular growth, a detailed understanding of the activation of the VEGF-C and VEGF-D is needed before such concepts can be converted into safe and efficacious therapies.
  • 6.3K
  • 30 Mar 2021
Topic Review
Chemistry in Health Care
The importance of chemistry in nursing is evident in every aspect of patient care. From understanding drug interactions and diagnostic tools to interpreting biochemical data and embracing innovative technologies.
  • 6.3K
  • 31 Oct 2024
Topic Review
Euler–Mascheroni Constant
The Euler–Mascheroni constant (also called Euler's constant) is a mathematical constant recurring in analysis and number theory, usually denoted by the lowercase Greek letter gamma (γ). It is defined as the limiting difference between the harmonic series and the natural logarithm, denoted here by [math]\displaystyle{ \log: }[/math] Here, [math]\displaystyle{ \lfloor x\rfloor }[/math] represents the floor function. The numerical value of the Euler–Mascheroni constant, to 50 decimal places, is: 0.57721566490153286060651209008240243104215933593992... 
  • 6.3K
  • 02 Dec 2022
Topic Review
48,XXXY Syndrome
48,XXXY syndrome is a chromosomal condition in boys and men that causes intellectual disability, developmental delays, physical differences, and an inability to father biological children (infertility). Its signs and symptoms vary among affected individuals.
  • 6.3K
  • 23 Dec 2020
Topic Review
Corynebacterium
Corynebacterium species are frequent constituents of the normal bacterial flora of the conjunctival sac and are common as well on human skin and mucous membranes and in the intestines.
  • 6.3K
  • 18 Mar 2021
Topic Review
Effects of Exercise on the Autonomic Nervous System
The autonomic nervous system (ANS) has an important impact on health in general. In response to environmental demands, homeostatic processes are often compromised, therefore determining an increase in the sympathetic nervous system (SNS)’s functions and a decrease in the parasympathetic nervous system (PNS)’s functions.
  • 6.3K
  • 21 Feb 2022
Topic Review
The White Sea
The White Sea is a small shallow semi-closed sea in the North-West of Russia. It is strongly affected by induced tides, so the tidal motion dominates in the sea. Sea ice is seasonal and the water salinity is less than in the neighbouring Barents sea due to strong river discharge. In this entry, we focus on the sources of data on the Sea.
  • 6.3K
  • 21 Jan 2021
Topic Review
2020 Nintendo Data Leak
The 2020 Nintendo data leak, more commonly referred to as the Nintendo Gigaleak is a series of leaks of data from Japanese video game company Nintendo on the anonymous imageboard website 4chan. The releasing of data started in March 2018, but became most prominent in 2020. Nine main sets of data leaked on 4chan, ranging from game and console source code to internal documentation and development tools. The name "Gigaleak" mainly refers to the second leak on July 24, 2020, which was 3 gigabytes in size. The leaks are believed to have come either from companies contracted by Nintendo in the design of these consoles, or from individuals previously convicted of intrusion into Nintendo systems. An earlier, much smaller leak had also occurred in 2018 which had the Nintendo Space World 1997 demos for Pokémon Gold and Silver leaked. The leaks are infamous for the sheer size and the amount of internal material leaked; video game journalists have described the magnitude of the leaks as unprecedented, and suggested that they might have significant effects for emulation and to preservationists, in addition to the legal questions posed by the leak. As of May 2021, Nintendo has not made any official response.
  • 6.3K
  • 14 Oct 2022
Topic Review
Dracorex
Dracorex is a controversial dinosaur genus of the family Pachycephalosauridae, from the Late Cretaceous of North America. The type (and only known) species is Dracorex hogwartsia, meaning "dragon king of Hogwarts". This dinosaur is named for the wizard school in Harry Potter books. It is known from one nearly complete skull (the holotype TCMI 2004.17.1), as well as four cervical vertebrae: the atlas, third, eighth and ninth. These were discovered in the Hell Creek Formation in South Dakota by three amateur paleontologists from Sioux City, in the U.S. state of Iowa. The skull was subsequently donated to the Children's Museum of Indianapolis for study in 2004, and was formally described by Bob Bakker and Robert Sullivan in 2006. However, Jack Horner et al. suspect that it is a juvenile Pachycephalosaurus and an analysis of pachycephalosaur fossils by a joint team from the University of California, Berkeley and the Museum of the Rockies has questioned the validity of two named genera of pachycephalosaur, Dracorex and Stygimoloch. According to the team, specimens of Dracorex and Stygimoloch might actually represent earlier growth stages of Pachycephalosaurus. This has been supported in a 2016 analysis of the youngest Pachycephalosaurus material known, which indicates that the unique features of Dracorex represent instead ontogenetically variant features on a Pachycephalosaurus growth curve.
  • 6.3K
  • 03 Nov 2022
Topic Review
Combinatorial Peptide Library
Completely randomizing even relatively short peptides would require a library size surpassing the capacities of most platforms. Sampling the complete mutational space for peptides exceeding 8–9 residues is therefore practically impossible, and gene diversification strategies only allow for generation and subsequent interrogation of a limited subset of the entire theoretical peptide population. Directed evolution of peptides therefore strives to ascend towards peak activity through mutational steps, accumulating beneficial mutational over several generations, resulting in improved phenotype. We briefly discuss combinatorial library platforms and take an in-depth look at diversification techniques for random and focused mutagenesis. 
  • 6.3K
  • 30 Oct 2020
Topic Review
Hydrometallurgy of Lithium Batteries
Spent lithium batteries can cause pollution to the soil and seriously threaten the safety and property of people. They contain valuable metals, such as cobalt and lithium, which are nonrenewable resources, and their recycling and treatment have important economic, strategic, and environmental benefits. The hydrometallurgy process uses reagents such as hydrochloric acid (HCl), nitric acid (HNO3), sulfuric acid (H2SO4), phosphoric acid (H3PO4), organic acids, and hydrogen peroxide (H2O2) to extract and separate the cathode metals, usually operating below 100 °C, and can recover lithium in addition to the other transition metals.
  • 6.3K
  • 15 Mar 2022
Topic Review
Materials Science, Glasses
Glasses are solid amorphous materials which transform into liquids upon heating through the glass transition. The International Commission on Glass defines glass as a state of matter, usually produced when a viscous molten material is cooled rapidly to below its glass transition temperature, with insufficient time for a regular crystal lattice to form. The solid-like behaviour of glasses is separated from the liquid-like behaviour at higher temperatures by the glass transition temperature, Tg. The IUPAC Compendium on Chemical Terminology defines glass transition as a second order transition in which a supercooled melt yields, on cooling, a glassy structure. It states that below the glass-transition temperature the physical properties of glasses vary in a manner similar to those of the crystalline phase. Moreover, it is deemed that the bonding structure of glasses has the same symmetry signature in terms of Hausdorff-Besikovitch dimensionality of chemical bonds as for the crystalline materials. 
  • 6.3K
  • 09 May 2024
Biography
Thomas Townsend Brown
Thomas Townsend Brown (March 18, 1905 – October 27, 1985)[1] was an United States inventor whose research into odd electrical effects led him to believe he had discovered a connection between strong electric fields and gravity, a type of antigravity effect. Instead of being an antigravity force, what Brown observed has generally been attributed to electrohydrodynamics, the movement of charged
  • 6.3K
  • 19 Dec 2022
Topic Review
Islamic Primary Schools in the Netherlands
Because of the constitutional Freedom of education in the Netherlands, everyone can establish a school and is entitled to full state funding. There now are 52 primary Islamic schools, with around 12,500 pupils mostly of Turkish and Moroccan descent. They focus on developing an Islamic religious identity, and high educational quality and pupil achievement. Because most pupils come from socioeconomic disadvantaged backgrounds, the schools receive nearly twice as much budget than schools with a predominantly non-disadvantaged population. The existence of Islamic schools has always been controversial. Their output in terms of academic achievement is relatively high, however. In an absolute sense they achieve below the “average” Dutch school, but when compared with schools with the same disadvantaged pupil population, they achieve better. Lately, there have been problems with secondary Islamic schools in the Netherlands. As a result, several politicians propose to abolish the Freedom of education act.  
  • 6.3K
  • 03 Nov 2020
Topic Review
Electrocommunication
Electrocommunication is the communication method used by weakly-electric fish. Weakly-electric fish are a group of animals that utilize a communicating channel that is "invisible" to most other animals: electric signaling. Electric fish communicate by generating an electric field that a second individual receives with its electroreceptors. The fish interprets the message using the signal's frequencies, waveforms, delay, etc. The best studied species are two freshwater lineages- the African Mormyridae and the South American Gymnotiformes. While weakly-electric fish are the only group that have been identified to carry out both generation and reception of electric fields, other species either generate signals or receive them, but not both. Animals that either generate or receive electric fields are found only in wet or aquatic environments due to water's relatively low electrical resistance, compared to other substances (e.g. air). So far, communication between electric fish has been identified mainly to serve the purpose of conveying information such as: species courtship and biological sex motivational status (e.g. attack warning, submission, etc.) environmental conditions
  • 6.3K
  • 31 Oct 2022
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