5/5/2023 0 Comments Smaller particles![]() (Image credit: xenotar via Getty Images) (opens in new tab)Īlthough the theory was clever, it didn't immediately catch on because there was no experimental evidence for quarks. The Large Hadron Collider occupies a circular underground tunnel nearly 17 miles (27 kilometers) in circumference. The up and down doesn't really refer to anything, while the strange quark had a quantum number of strangeness of –1, hence why it is called "strange", whereas the up and down quarks have a strangeness of 0. These quarks were referred to as "up", "down" and "strange" quarks. Gell-Mann, who was ever one for cooky and memorable names, called them quarks, derived from a line in James Joyce's experimental novel, Finnegan's Wake: "Three quarks for Muster Mark!" In the novel, the quarks refer to the three children of the main character, Mr Mark. Zweig called these tiny, elementary particles "aces", but the name didn't catch on. These degrees of freedom are called multiplets, and the pattern in which these multiplets could be arranged between different particles led Gell-Mann and Zweig to believe that the particles and their multiplets could be explained if each particle was formed from two or three smaller particles. Moreover, the quantum numbers of a given particle have "degrees of freedom" - basically the range of values that these numbers can have. If a particle with a specific quantum number decays, then its by-products must add up to those quantum numbers that the decayed particle had. Quantum numbers, like strangeness, charge and spin, have to be conserved. Gell-Mann realized that there must be an unknown quantum property at work, which he named "strangeness" because of the unexpectedness of it all. Most puzzling was the existence of particles called hyperons, which were unstable and decayed very quickly, but not into the particles they were expected to decay into. This theory ultimately became known as the Standard Model, but in order to get there several vital discoveries had to be made, including that of quarks. It was a bit like botany, cataloging the various types and their properties, but what was missing was an underlying theory behind their existence. Higgs boson: The 'God Particle' explainedīy the 1950s, physicists were building up a library of known particles. Even though one has to take into account different concentrations in ambient air as well as differences in respiratory system deposition of the size fractions, the potential of coarse particles to induce pulmonary effects should not be neglected.- 10 cosmic mysteries the Large Hadron Collider could unravel Overall, coarse PM was found to have an inflammatory potential similar to fine PM on an equal mass basis. The allergic responses tended to be more associated with the organic fraction (PAH) of particles, whereas the inflammatory reactions seemed to be more associated with metals and endotoxin. The data indicate that coarse particles can induce at least as strong inflammatory responses as fine particles. In European-wide studies such as the Respiratory Allergy and Inflammation due to Air Pollution (RAIAP) study, particles have been sampled in different locations to study season- and site-dependent variations in responses particles, such as markers of inflammatory and allergic reactions in cells and animals. A single, specific component of the mineral particles, explaining the differences in response, has not been identified. The ability of the particles to generate reactive oxygen species in vitro was not correlated with either inflammatory markers or apoptosis, suggesting that other mechanisms are at play. Our studies show that mineral particle-induced apoptosis mostly seems to depend on particle size, whereas composition and surface reactivity appeared to be most important for the proinflammatory potential of the particles. Moreover, different particle characteristics appear to be involved in different biological effects in vitro. ![]() Hence, the importance of size and surface area does not override the importance of particle composition. However, correlation for variations in surface area could not account for variation in biological reactivity among particles of differential composition. Experimental studies have shown that smaller particles induce stronger biological effects than larger particles of similar composition, due to their larger surface area to mass ratio. ![]() A primary goal of current research on particle-induced health effects is to reveal the critical characteristics that determine their biological effects. ![]()
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