WikiJournal of Science/Volume 3 Issue 1
WikiJournal of Science
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VOLUME 3 (2020)
ISSUE 1
Previous issue
Author: Boris Tsirelson
Contrary to popular misconception, the question in the title is far from simple. It involves sets of numbers on the first level, sets of sets of numbers on the second level, and so on, endlessly. The infinite hierarchy of the levels involved distinguishes the concept of "definable number" from such notions as "natural number", "rational number", "algebraic number", "computable number" etc.
doi: 10.15347/WJS/2020.008
Authors: Subir Sarker, Jade Forwood, Shane Raidal
The beak and feather disease virus (BFDV) causes psittacine beak and feather disease, an often chronic and fatal disease in psittacine birds. The virus most commonly infects psittacine birds, but is also capable of infecting non-psittacine bird species in Australasia. The virus induces an immunosuppressive condition with chronic symmetrical irreversible loss of feather, as well as beak and claw deformities eventually leading to death. No specific treatment is currently commercially available for infected birds; however, a combination of quarantine and hygiene control, diagnostic testing and enhancing flock adaptive immunity is recommended to provide the most effective and sustainable control. Recent structural determination of BFDV capsid protein provides insights into the different assemblies that can be formed from one of the smallest known DNA viruses.
doi: 10.15347/WJS/2020.007
Author: Keshab Magar
E-extension is an approach to agricultural knowledge extension through electronic technologies where online platforms such as web sites, mobile applications and social media are used. Low cost and high effectiveness suggest substantial future possibilities. Nepal's rapid increase in internet usage provides the potential to employ e-extension as a valuable mechanism in the prevailing system of agriculture extension, providing direct advantages to Nepalese farmers. Access to e-extension enables timely updates to newer technologies, information and e-news, with better chances of broad discourse in Nepalese agriculture. This paper aims to document recent initiatives in current e-extension developments in Nepal. Constraints may arise from issues of user-friendliness, affordability and reliability. If promoted with innovation and considerations of actual access, e-extension can have multiple positive impacts on Nepalese agriculture in the near future.
doi: 10.15347/WJS/2020.006
Author: Jan Kameníček
On 13 October 1990, meteoroid EN131090, with an estimated mass of 44 kg, entered the Earth's atmosphere above Czechoslovakia and Poland and, after a few seconds, returned to space. Observations of such events are quite rare; this was the second recorded using scientific astronomical instruments (after the 1972 Great Daylight Fireball) and the first recorded from two distant positions, which enabled the calculation of several of its orbital characteristics. The encounter with Earth significantly changed its orbit and, to a smaller extent, some of its physical properties (mass and structure of its outer layer).
doi: 10.15347/WJS/2020.005
Authors: Deepesh Nagarajan, Neha Nanajkar
Proteins are biological polymers composed of linear chains of 20 different amino acids. The sequence of amino acids for every protein is unique, and guides its folding into intricate 3-dimensional shapes, known as protein folds. The TIM barrel is one such fold, and is characterized by an interior 8-stranded β-barrel, surrounded and enclosed by 8 α-helices. TIM barrels are named after triose phosphate isomerase (TIM), an enzyme first structurally characterized in 1975, which lends its name to the fold. TIM barrels are prevalent in all forms of life, and across diverse metabolic pathways, with over 10% of all enzymes adopting this fold. The majority of TIM barrels are thought to have evolved from a common ancestor through gene duplication and domain fusion processes. TIM barrels have been created by protein engineers using preexisting half-barrel templates and de novo, without an existing template. This review will discuss the topological, structural, evolutionary, and design characteristics of TIM barrels in detail.
doi: 10.15347/WJS/2020.004
Author: Bryan Ericksen
Virtual colony count (VCC) is a kinetic, 96-well microbiological assay originally developed to measure the activity of defensins. It has since been applied to other antimicrobial peptides including LL-37. It utilizes a method of enumerating bacteria called quantitative growth kinetics, which compares the time taken for a bacterial batch culture to reach a threshold optical density with that of a series of calibration curves. The name VCC has also been used to describe the application of quantitative growth kinetics to enumerate bacteria in cell culture infection models. Antimicrobial susceptibility testing (AST) can be done on 96-well plates by diluting the antimicrobial agent at varying concentrations in broth inoculated with bacteria and measuring the minimum inhibitory concentration that results in no growth. However, these methods cannot be used to study some membrane-active antimicrobial peptides, which are inhibited by the broth itself. The virtual colony count procedure takes advantage of this fact by first exposing bacterial cells to the active antimicrobial agent in a low-salt buffer for two hours, then simultaneously inhibiting antimicrobial activity and inducing exponential growth by adding broth. The growth kinetics of surviving cells can then be monitored using a temperature-controlled plate reader. The time taken for each growth curve to reach a threshold change in optical density is then converted into virtual survival values, which serve as a measure of antimicrobial activity. [...] doi: 10.15347/WJS/2020.003
Authors: Tyler Rushton, Sebastian Dworkin
The Grainyhead-like genes are a family of highly conserved transcription factors that are functionally and structurally homologous across a large number of vertebrate and invertebrate species. For an estimated 100 million years or more, this genetic family has been evolving alongside life to fine tune the regulation of epithelial barrier integrity during development, fine-tuning epithelial barrier establishment, maintenance and subsequent homeostasis. The three main orthologues, Grainyhead-like 1, 2 and 3, regulate numerous genetic pathways within different organisms and perform analogous roles between them, ranging from neural tube closure, wound healing, establishment of the craniofacial skeleton and repair of the epithelium. When Grainyhead-like genes are impaired, due to genetic mutations in embryogenesis, it will cause the organism to present with developmental defects that largely affect ectodermal (and sometimes also endodermal) tissues in which they are expressed. These subsequent congenital disorders, including cleft lip and exencephaly, vary greatly in their severity and impact on the quality of life for the affected individual. There is so much more to learn about the function of these genes and the more complex roles of Grainyhead-like genes are yet to be discovered.
doi: 10.15347/WJS/2020.002
Author: Iain Reid
Paranthodon (/pəˈrænθədɒn/) is a genus of extinct stegosaurian dinosaur that lived in South Africa during the Early Cretaceous, between 139 and 131 million years ago. Discovered in 1845, it was one of the first stegosaurians found. Its only remains, a partial skull and isolated teeth, were found in the Kirkwood Formation. British paleontologist Richard Owen initially identified the fragments as those of the pareiasaur Anthodon. After remaining untouched for years in the British Museum of Natural History, the partial skull was identified by South African paleontologist Robert Broom as belonging to a different genus; he named the specimen Palaeoscincus africanus. Several years later, Hungarian paleontologist Franz Nopcsa, unaware of Broom's new name, similarly concluded that it represented a new taxon, and named it Paranthodon owenii. Since Nopcsa's species name was assigned after Broom's, and Broom did not assign a new genus, both names are now synonyms of the current binomial, Paranthodon africanus. The genus name combines the Ancient Greek para (near) with the genus name Anthodon, to represent the initial referral of the remains. [...] doi: 10.15347/WJS/2020.001
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