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Topic Review
Nontuberculous Mycobacteria
Nontuberculous mycobacteria (NTM) are the additional opportunistic pathogenic mycobacterial complex groups that consists of M. avium, M. marinum, M. hemophilum, M. kansasii, M. scrofulaceum, M. gordonae, M. abscessus, M. fortuitum and M. chelonae. They do not cause TB; however, they can produce pulmonary infections, lymphadenitis, skin disease, endometritis and disseminated disease. Thus, NTM are denoted by other names such as environmental mycobacteria or mycobacteria other than tuberculosis (MOTT) and atypical mycobacteria (ATM) [1–4].
  • 2.5K
  • 06 Nov 2020
Topic Review
History of Life
The history of life on Earth traces the processes by which living and fossil organisms evolved, from the earliest emergence of life to the present day. Earth formed about 4.5 billion years ago (abbreviated as Ga, for gigaannum) and evidence suggests that life emerged prior to 3.7 Ga. Although there is some evidence of life as early as 4.1 to 4.28 Ga, it remains controversial due to the possible non-biological formation of the purported fossils. The similarities among all known present-day species indicate that they have diverged through the process of evolution from a common ancestor. Only a very small percentage of species have been identified: one estimate claims that Earth may have 1 trillion species. However, only 1.75–1.8 million have been named and 1.8 million documented in a central database. These currently living species represent less than one percent of all species that have ever lived on Earth. The earliest evidence of life comes from biogenic carbon signatures and stromatolite fossils discovered in 3.7 billion-year-old metasedimentary rocks from western Greenland. In 2015, possible "remains of biotic life" were found in 4.1 billion-year-old rocks in Western Australia. In March 2017, putative evidence of possibly the oldest forms of life on Earth was reported in the form of fossilized microorganisms discovered in hydrothermal vent precipitates in the Nuvvuagittuq Belt of Quebec, Canada, that may have lived as early as 4.28 billion years ago, not long after the oceans formed 4.4 billion years ago, and not long after the formation of the Earth 4.54 billion years ago. Microbial mats of coexisting bacteria and archaea were the dominant form of life in the early Archean Epoch and many of the major steps in early evolution are thought to have taken place in this environment. The evolution of photosynthesis, around 3.5 Ga, eventually led to a buildup of its waste product, oxygen, in the atmosphere, leading to the great oxygenation event, beginning around 2.4 Ga. The earliest evidence of eukaryotes (complex cells with organelles) dates from 1.85 Ga, and while they may have been present earlier, their diversification accelerated when they started using oxygen in their metabolism. Later, around 1.7 Ga, multicellular organisms began to appear, with differentiated cells performing specialised functions. Sexual reproduction, which involves the fusion of male and female reproductive cells (gametes) to create a zygote in a process called fertilization is, in contrast to asexual reproduction, the primary method of reproduction for the vast majority of macroscopic organisms, including almost all eukaryotes (which includes animals and plants). However the origin and evolution of sexual reproduction remain a puzzle for biologists though it did evolve from a common ancestor that was a single celled eukaryotic species. Bilateria, animals having a left and a right side that are mirror images of each other, appeared by 555 Ma (million years ago). Algae-like multicellular land plants are dated back even to about 1 billion years ago, although evidence suggests that microorganisms formed the earliest terrestrial ecosystems, at least 2.7 Ga. Microorganisms are thought to have paved the way for the inception of land plants in the Ordovician period. Land plants were so successful that they are thought to have contributed to the Late Devonian extinction event. (The long causal chain implied seems to involve the success of early tree archaeopteris (1) drew down CO2 levels, leading to global cooling and lowered sea levels, (2) roots of archeopteris fostered soil development which increased rock weathering, and the subsequent nutrient run-off may have triggered algal blooms resulting in anoxic events which caused marine-life die-offs. Marine species were the primary victims of the Late Devonian extinction.) Ediacara biota appear during the Ediacaran period, while vertebrates, along with most other modern phyla originated about 525 Ma during the Cambrian explosion. During the Permian period, synapsids, including the ancestors of mammals, dominated the land, but most of this group became extinct in the Permian–Triassic extinction event 252 Ma. During the recovery from this catastrophe, archosaurs became the most abundant land vertebrates; one archosaur group, the dinosaurs, dominated the Jurassic and Cretaceous periods. After the Cretaceous–Paleogene extinction event 66 Ma killed off the non-avian dinosaurs, mammals increased rapidly in size and diversity. Such mass extinctions may have accelerated evolution by providing opportunities for new groups of organisms to diversify.
  • 2.5K
  • 18 Oct 2022
Topic Review
Internet Pornography
Internet pornography is any pornography that is accessible over the internet, primarily via websites, FTP servers peer-to-peer file sharing, or Usenet newsgroups. The availability of widespread public access to the World Wide Web in late 1990s led to the growth of internet pornography. A 2015 study finds "a big jump" in pornography viewing over the past few decades, with the largest increase occurring between people born in the 1970s and those born in the 1980s. While the study's authors note this increase is "smaller than conventional wisdom might predict," it's still quite significant. Those who were born in the 1980s onward are also the first to grow up in a world where they have access to the internet beginning in their teenage years, and this early exposure and access to internet pornography may be the primary driver of the increase. The sex and tech conference series Arse Elektronika dedicated their 2007 conference to what they call pr0nnovation. The con presented a keynote by culture theorist Mark Dery and published a reader about the subject. (As of 2018), a single company, MindGeek, owns and operates many popular pornographic websites, including video sharing services Pornhub, RedTube, and YouPorn, as well as adult film producers Brazzers, Digital Playground, Men.com, Reality Kings, and Sean Cody, among others, but does not own the websites xHamster and XVideos. It has been alleged to be a monopoly.
  • 2.5K
  • 25 Oct 2022
Topic Review
L-Twin
A V-twin engine, also called a V2 engine, is a two-cylinder piston engine where the cylinders share a common crankshaft and are arranged in a V configuration. Although widely associated with motorcycles (installed either transversely or longitudinally), V-twin engines have also been used for industrial engines and in several small cars. The V-twin design dates back to the late 1880s.
  • 2.5K
  • 28 Nov 2022
Topic Review
Pathophysiology of Sepsis
Sepsis is a life-threatening condition characterized by an uncontrolled inflammatory response to an infectious agent and its antigens. Immune cell activation against the antigens causes severe distress that mediates a strong inflammatory response in vital organs. Sepsis is responsible for a high rate of morbidity and mortality in immunosuppressed patients. 
  • 2.5K
  • 13 Mar 2023
Topic Review
Li7La3Zr2O12 (LLZO): An Overview
Li7La3Zr2O12 (LLZO) is an inorganic garnet type solid electrolyte which has proven to be one of the most promising electrolytes because of its high ionic conductivity at room temperature, low activation energy, good chemical and electrochemical stability, and wide potential window.
  • 2.5K
  • 03 Aug 2021
Topic Review
Addiction and Spending in Gacha Games
Gacha games are the most dominant games on the mobile market. These are free-to-play games with a lottery-like system, where the user pays with in-game currency to enter a draw in order to obtain the character or item they want. If a player does not obtain what he hoped for, there is the option of paying with his own money for more draws, and this is the main way to monetize the Gacha game.
  • 2.5K
  • 21 Jul 2023
Topic Review
Rhizosphere
The rhizosphere serves as a hotspot for diverse microbial activity. It is an intricate ecosystem comprising nutrient-rich soil that surrounds the plant roots, which provides a pool for plant–microbe communication. The term “Rhizomicrobiome” is defined as a microbial community that is present in the rhizosphere. A variety of microorganisms reside within the rhizosphere, including bacteria, fungi, nematodes, protists, and invertebrates. Most of the microbiome studies within the context of rhizosphere signaling have been focused on the bacteria and fungi that make up the major portion of the rhizosphere microbiome.
  • 2.5K
  • 17 May 2022
Topic Review
Battery Equalizer Circuits
In this entry, several battery equalizer circuits are reviewed and simulated. In addition, a table is presented where the main characteristics of the equalizers are summarized. These characteristics are used to assign a score to each circuit with respect to how many characteristics are similar to the ideal equalizer. Finally, a methodology is presented to compare these equalizers, taking into account the results obtained from the table.
  • 2.5K
  • 25 Nov 2020
Topic Review
Power Generation in Sewage-Water Treatment Plants
Sewage-water treatment comprehends primary, secondary, and tertiary steps to produce reusable water after removing sewage contaminants. However, a sewage-water treatment plant is typically a power and energy consumer and produces high volumes of sewage sludge mainly generated in the primary and secondary steps. The use of more efficient anaerobic digestion of sewage water with sewage sludge can produce reasonable flowrates of biogas, which is shown to be a consolidated strategy towards the energy self-sufficiency and economic feasibility of sewage-water treatment plants. Anaerobic digestion can also reduce the carbon footprint of energy sources since the biogas produced can replace fossil fuels for electricity generation. 
  • 2.5K
  • 05 May 2022
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