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Dubnium
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Discovery
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24998Cf + 157N → 260105 + 4 nThese results did not confirm the JINR findings regarding the 9.4 MeV or 9.7 MeV alpha decay of 260105, leaving only 261105 as a possibly produced isotope.JINR then attempted another experiment to create element 105, published in a report in May 1970. They claimed that they had synthesized more nuclei of element 105 and that the experiment confirmed their previous work. According to the paper, the isotope produced by JINR was probably 261105, or possibly 260105. This report included an initial chemical examination: the thermal gradient version of the gas-chromatography method was applied to demonstrate that the chloride of what had formed from the SF activity nearly matched that of niobium pentachloride, rather than hafnium tetrachloride. The team identified a 2.2-second SF activity in a volatile chloride portraying eka-tantalum properties, and inferred that the source of the SF activity must have been element 105.In June 1970, JINR made improvements on their first experiment, using a purer target and reducing the intensity of transfer reactions by installing a collimator before the catcher. This time, they were able to find 9.1 MeV alpha activities with daughter isotopes identifiable as either 256103 or 257103, implying that the original isotope was either 260105 or 261105.
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Dubnium
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Discovery
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Naming controversy JINR did not propose a name after their first report claiming synthesis of element 105, which would have been the usual practice. This led LBL to believe that JINR did not have enough experimental data to back their claim. After collecting more data, JINR proposed the name bohrium (Bo) in honor of the Danish nuclear physicist Niels Bohr, a founder of the theories of atomic structure and quantum theory; they soon changed their proposal to nielsbohrium (Ns) to avoid confusion with boron. Another proposed name was dubnium. When LBL first announced their synthesis of element 105, they proposed that the new element be named hahnium (Ha) after the German chemist Otto Hahn, the "father of nuclear chemistry", thus creating an element naming controversy.In the early 1970s, both teams reported synthesis of the next element, element 106, but did not suggest names. JINR suggested establishing an international committee to clarify the discovery criteria. This proposal was accepted in 1974 and a neutral joint group formed. Neither team showed interest in resolving the conflict through a third party, so the leading scientists of LBL—Albert Ghiorso and Glenn Seaborg—traveled to Dubna in 1975 and met with the leading scientists of JINR—Georgy Flerov, Yuri Oganessian, and others—to try to resolve the conflict internally and render the neutral joint group unnecessary; after two hours of discussions, this failed. The joint neutral group never assembled to assess the claims, and the conflict remained unresolved. In 1979, IUPAC suggested systematic element names to be used as placeholders until permanent names were established; under it, element 105 would be unnilpentium, from the Latin roots un- and nil- and the Greek root pent- (meaning "one", "zero", and "five", respectively, the digits of the atomic number). Both teams ignored it as they did not wish to weaken their outstanding claims.In 1981, the Gesellschaft für Schwerionenforschung (GSI; Society for Heavy Ion Research) in Darmstadt, Hesse, West Germany, claimed synthesis of element 107; their report came out five years after the first report from JINR but with greater precision, making a more solid claim on discovery. GSI acknowledged JINR's efforts by suggesting the name nielsbohrium for the new element. JINR did not suggest a new name for element 105, stating it was more important to determine its discoverers first.
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Dubnium
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Discovery
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In 1985, the International Union of Pure and Applied Chemistry (IUPAC) and the International Union of Pure and Applied Physics (IUPAP) formed a Transfermium Working Group (TWG) to assess discoveries and establish final names for the controversial elements. The party held meetings with delegates from the three competing institutes; in 1990, they established criteria on recognition of an element, and in 1991, they finished the work on assessing discoveries and disbanded. These results were published in 1993. According to the report, the first definitely successful experiment was the April 1970 LBL experiment, closely followed by the June 1970 JINR experiment, so credit for the discovery of the element should be shared between the two teams.LBL said that the input from JINR was overrated in the review. They claimed JINR was only able to unambiguously demonstrate the synthesis of element 105 a year after they did. JINR and GSI endorsed the report.In 1994, IUPAC published a recommendation on naming the disputed elements. For element 105, they proposed joliotium (Jl) after the French physicist Frédéric Joliot-Curie, a contributor to the development of nuclear physics and chemistry; this name was originally proposed by the Soviet team for element 102, which by then had long been called nobelium. This recommendation was criticized by the American scientists for several reasons. Firstly, their suggestions were scrambled: the names rutherfordium and hahnium, originally suggested by Berkeley for elements 104 and 105, were respectively reassigned to elements 106 and 108. Secondly, elements 104 and 105 were given names favored by JINR, despite earlier recognition of LBL as an equal co-discoverer for both of them. Thirdly and most importantly, IUPAC rejected the name seaborgium for element 106, having just approved a rule that an element could not be named after a living person, even though the 1993 report had given the LBL team the sole credit for its discovery.In 1995, IUPAC abandoned the controversial rule and established a committee of national representatives aimed at finding a compromise. They suggested seaborgium for element 106 in exchange for the removal of all the other American proposals, except for the established name lawrencium for element 103. The equally entrenched name nobelium for element 102 was replaced by flerovium after Georgy Flerov, following the recognition by the 1993 report that that element had been first synthesized in Dubna. This was rejected by American scientists and the decision was retracted. The name flerovium was later used for element 114.In 1996, IUPAC held another meeting, reconsidered all names in hand, and accepted another set of recommendations; it was approved and published in 1997. Element 105 was named dubnium (Db), after Dubna in Russia, the location of the JINR; the American suggestions were used for elements 102, 103, 104, and 106. The name dubnium had been used for element 104 in the previous IUPAC recommendation. The American scientists "reluctantly" approved this decision. IUPAC pointed out that the Berkeley laboratory had already been recognized several times, in the naming of berkelium, californium, and americium, and that the acceptance of the names rutherfordium and seaborgium for elements 104 and 106 should be offset by recognizing JINR's contributions to the discovery of elements 104, 105, and 106.Even after 1997, LBL still sometimes used the name hahnium for element 105 in their own material, doing so as recently as 2014. However, the problem was resolved in the literature as Jens Volker Kratz, editor of Radiochimica Acta, refused to accept papers not using the 1997 IUPAC nomenclature.
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Dubnium
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Isotopes
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Dubnium, having an atomic number of 105, is a superheavy element; like all elements with such high atomic numbers, it is very unstable. The longest-lasting known isotope of dubnium, 268Db, has a half-life of around a day. No stable isotopes have been seen, and a 2012 calculation by JINR suggested that the half-lives of all dubnium isotopes would not significantly exceed a day. Dubnium can only be obtained by artificial production.The short half-life of dubnium limits experimentation. This is exacerbated by the fact that the most stable isotopes are the hardest to synthesize. Elements with a lower atomic number have stable isotopes with a lower neutron–proton ratio than those with higher atomic number, meaning that the target and beam nuclei that could be employed to create the superheavy element have fewer neutrons than needed to form these most stable isotopes. (Different techniques based on rapid neutron capture and transfer reactions are being considered as of the 2010s, but those based on the collision of a large and small nucleus still dominate research in the area.)Only a few atoms of 268Db can be produced in each experiment, and thus the measured lifetimes vary significantly during the process. As of 2022, following additional experiments performed at the JINR's Superheavy Element Factory (which started operations in 2019), the half-life of 268Db is measured to be 16+6−4 hours. The second most stable isotope, 270Db, has been produced in even smaller quantities: three atoms in total, with lifetimes of 33.4 h, 1.3 h, and 1.6 h. These two are the heaviest isotopes of dubnium to date, and both were produced as a result of decay of the heavier nuclei 288Mc and 294Ts rather than directly, because the experiments that yielded them were originally designed in Dubna for 48Ca beams. For its mass, 48Ca has by far the greatest neutron excess of all practically stable nuclei, both quantitative and relative, which correspondingly helps synthesize superheavy nuclei with more neutrons, but this gain is compensated by the decreased likelihood of fusion for high atomic numbers.
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Dubnium
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Predicted properties
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According to the periodic law, dubnium should belong to group 5, with vanadium, niobium, and tantalum. Several studies have investigated the properties of element 105 and found that they generally agreed with the predictions of the periodic law. Significant deviations may nevertheless occur, due to relativistic effects, which dramatically change physical properties on both atomic and macroscopic scales. These properties have remained challenging to measure for several reasons: the difficulties of production of superheavy atoms, the low rates of production, which only allows for microscopic scales, requirements for a radiochemistry laboratory to test the atoms, short half-lives of those atoms, and the presence of many unwanted activities apart from those of synthesis of superheavy atoms. So far, studies have only been performed on single atoms.
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Dubnium
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Predicted properties
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Atomic and physical A direct relativistic effect is that as the atomic numbers of elements increase, the innermost electrons begin to revolve faster around the nucleus as a result of an increase of electromagnetic attraction between an electron and a nucleus. Similar effects have been found for the outermost s orbitals (and p1/2 ones, though in dubnium they are not occupied): for example, the 7s orbital contracts by 25% in size and is stabilized by 2.6 eV.A more indirect effect is that the contracted s and p1/2 orbitals shield the charge of the nucleus more effectively, leaving less for the outer d and f electrons, which therefore move in larger orbitals. Dubnium is greatly affected by this: unlike the previous group 5 members, its 7s electrons are slightly more difficult to extract than its 6d electrons.
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Dubnium
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Predicted properties
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Another effect is the spin–orbit interaction, particularly spin–orbit splitting, which splits the 6d subshell—the azimuthal quantum number ℓ of a d shell is 2—into two subshells, with four of the ten orbitals having their ℓ lowered to 3/2 and six raised to 5/2. All ten energy levels are raised; four of them are lower than the other six. (The three 6d electrons normally occupy the lowest energy levels, 6d3/2.)A singly ionized atom of dubnium (Db+) should lose a 6d electron compared to a neutral atom; the doubly (Db2+) or triply (Db3+) ionized atoms of dubnium should eliminate 7s electrons, unlike its lighter homologs. Despite the changes, dubnium is still expected to have five valence electrons; 7p energy levels have not been shown to influence dubnium and its properties. As the 6d orbitals of dubnium are more destabilized than the 5d ones of tantalum, and Db3+ is expected to have two 6d, rather than 7s, electrons remaining, the resulting +3 oxidation state is expected to be unstable and even rarer than that of tantalum. The ionization potential of dubnium in its maximum +5 oxidation state should be slightly lower than that of tantalum and the ionic radius of dubnium should increase compared to tantalum; this has a significant effect on dubnium's chemistry.Atoms of dubnium in the solid state should arrange themselves in a body-centered cubic configuration, like the previous group 5 elements. The predicted density of dubnium is 21.6 g/cm3.
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Dubnium
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Predicted properties
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Chemical Computational chemistry is simplest in gas-phase chemistry, in which interactions between molecules may be ignored as negligible. Multiple authors have researched dubnium pentachloride; calculations show it to be consistent with the periodic laws by exhibiting the properties of a compound of a group 5 element. For example, the molecular orbital levels indicate that dubnium uses three 6d electron levels as expected. Compared to its tantalum analog, dubnium pentachloride is expected to show increased covalent character: a decrease in the effective charge on an atom and an increase in the overlap population (between orbitals of dubnium and chlorine).Calculations of solution chemistry indicate that the maximum oxidation state of dubnium, +5, will be more stable than those of niobium and tantalum and the +3 and +4 states will be less stable. The tendency towards hydrolysis of cations with the highest oxidation state should continue to decrease within group 5 but is still expected to be quite rapid. Complexation of dubnium is expected to follow group 5 trends in its richness. Calculations for hydroxo-chlorido- complexes have shown a reversal in the trends of complex formation and extraction of group 5 elements, with dubnium being more prone to do so than tantalum.
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Dubnium
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Experimental chemistry
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Experimental results of the chemistry of dubnium date back to 1974 and 1976. JINR researchers used a thermochromatographic system and concluded that the volatility of dubnium bromide was less than that of niobium bromide and about the same as that of hafnium bromide. It is not certain that the detected fission products confirmed that the parent was indeed element 105. These results may imply that dubnium behaves more like hafnium than niobium.The next studies on the chemistry of dubnium were conducted in 1988, in Berkeley. They examined whether the most stable oxidation state of dubnium in aqueous solution was +5. Dubnium was fumed twice and washed with concentrated nitric acid; sorption of dubnium on glass cover slips was then compared with that of the group 5 elements niobium and tantalum and the group 4 elements zirconium and hafnium produced under similar conditions. The group 5 elements are known to sorb on glass surfaces; the group 4 elements do not. Dubnium was confirmed as a group 5 member. Surprisingly, the behavior on extraction from mixed nitric and hydrofluoric acid solution into methyl isobutyl ketone differed between dubnium, tantalum, and niobium. Dubnium did not extract and its behavior resembled niobium more closely than tantalum, indicating that complexing behavior could not be predicted purely from simple extrapolations of trends within a group in the periodic table.This prompted further exploration of the chemical behavior of complexes of dubnium. Various labs jointly conducted thousands of repetitive chromatographic experiments between 1988 and 1993. All group 5 elements and protactinium were extracted from concentrated hydrochloric acid; after mixing with lower concentrations of hydrogen chloride, small amounts of hydrogen fluoride were added to start selective re-extraction. Dubnium showed behavior different from that of tantalum but similar to that of niobium and its pseudohomolog protactinium at concentrations of hydrogen chloride below 12 moles per liter. This similarity to the two elements suggested that the formed complex was either DbOX−4 or [Db(OH)2X4]−. After extraction experiments of dubnium from hydrogen bromide into diisobutyl carbinol (2,6-dimethylheptan-4-ol), a specific extractant for protactinium, with subsequent elutions with the hydrogen chloride/hydrogen fluoride mix as well as hydrogen chloride, dubnium was found to be less prone to extraction than either protactinium or niobium. This was explained as an increasing tendency to form non‐extractable complexes of multiple negative charges. Further experiments in 1992 confirmed the stability of the +5 state: Db(V) was shown to be extractable from cation‐exchange columns with α‐hydroxyisobutyrate, like the group 5 elements and protactinium; Db(III) and Db(IV) were not. In 1998 and 1999, new predictions suggested that dubnium would extract nearly as well as niobium and better than tantalum from halide solutions, which was later confirmed.The first isothermal gas chromatography experiments were performed in 1992 with 262Db (half-life 35 seconds). The volatilities for niobium and tantalum were similar within error limits, but dubnium appeared to be significantly less volatile. It was postulated that traces of oxygen in the system might have led to formation of DbOBr3, which was predicted to be less volatile than DbBr5. Later experiments in 1996 showed that group 5 chlorides were more volatile than the corresponding bromides, with the exception of tantalum, presumably due to formation of TaOCl3. Later volatility studies of chlorides of dubnium and niobium as a function of controlled partial pressures of oxygen showed that formation of oxychlorides and general volatility are dependent on concentrations of oxygen. The oxychlorides were shown to be less volatile than the chlorides.In 2004–05, researchers from Dubna and Livermore identified a new dubnium isotope, 268Db, as a fivefold alpha decay product of the newly created element 115. This new isotope proved to be long-lived enough to allow further chemical experimentation, with a half-life of over a day. In the 2004 experiment, a thin layer with dubnium was removed from the surface of the target and dissolved in aqua regia with tracers and a lanthanum carrier, from which various +3, +4, and +5 species were precipitated on adding ammonium hydroxide. The precipitate was washed and dissolved in hydrochloric acid, where it converted to nitrate form and was then dried on a film and counted. Mostly containing a +5 species, which was immediately assigned to dubnium, it also had a +4 species; based on that result, the team decided that additional chemical separation was needed. In 2005, the experiment was repeated, with the final product being hydroxide rather than nitrate precipitate, which was processed further in both Livermore (based on reverse phase chromatography) and Dubna (based on anion exchange chromatography). The +5 species was effectively isolated; dubnium appeared three times in tantalum-only fractions and never in niobium-only fractions. It was noted that these experiments were insufficient to draw conclusions about the general chemical profile of dubnium.In 2009, at the JAEA tandem accelerator in Japan, dubnium was processed in nitric and hydrofluoric acid solution, at concentrations where niobium forms NbOF−4 and tantalum forms TaF−6. Dubnium's behavior was close to that of niobium but not tantalum; it was thus deduced that dubnium formed DbOF−4. From the available information, it was concluded that dubnium often behaved like niobium, sometimes like protactinium, but rarely like tantalum.In 2021, the volatile heavy group 5 oxychlorides MOCl3 (M = Nb, Ta, Db) were experimentally studied at the JAEA tandem accelerator. The trend in volatilities was found to be NbOCl3 > TaOCl3 ≥ DbOCl3, so that dubnium behaves in line with periodic trends.
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Dependency grammar
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Dependency grammar
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Dependency grammar (DG) is a class of modern grammatical theories that are all based on the dependency relation (as opposed to the constituency relation of phrase structure) and that can be traced back primarily to the work of Lucien Tesnière. Dependency is the notion that linguistic units, e.g. words, are connected to each other by directed links. The (finite) verb is taken to be the structural center of clause structure. All other syntactic units (words) are either directly or indirectly connected to the verb in terms of the directed links, which are called dependencies. Dependency grammar differs from phrase structure grammar in that while it can identify phrases it tends to overlook phrasal nodes. A dependency structure is determined by the relation between a word (a head) and its dependents. Dependency structures are flatter than phrase structures in part because they lack a finite verb phrase constituent, and they are thus well suited for the analysis of languages with free word order, such as Czech or Warlpiri.
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Dependency grammar
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History
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The notion of dependencies between grammatical units has existed since the earliest recorded grammars, e.g. Pāṇini, and the dependency concept therefore arguably predates that of phrase structure by many centuries. Ibn Maḍāʾ, a 12th-century linguist from Córdoba, Andalusia, may have been the first grammarian to use the term dependency in the grammatical sense that we use it today. In early modern times, the dependency concept seems to have coexisted side by side with that of phrase structure, the latter having entered Latin, French, English and other grammars from the widespread study of term logic of antiquity. Dependency is also concretely present in the works of Sámuel Brassai (1800–1897), a Hungarian linguist, Franz Kern (1830-1894), a German philologist, and of Heimann Hariton Tiktin (1850–1936), a Romanian linguist.Modern dependency grammars, however, begin primarily with the work of Lucien Tesnière. Tesnière was a Frenchman, a polyglot, and a professor of linguistics at the universities in Strasbourg and Montpellier. His major work Éléments de syntaxe structurale was published posthumously in 1959 – he died in 1954. The basic approach to syntax he developed seems to have been seized upon independently by others in the 1960s and a number of other dependency-based grammars have gained prominence since those early works. DG has generated a lot of interest in Germany in both theoretical syntax and language pedagogy. In recent years, the great development surrounding dependency-based theories has come from computational linguistics and is due, in part, to the influential work that David Hays did in machine translation at the RAND Corporation in the 1950s and 1960s. Dependency-based systems are increasingly being used to parse natural language and generate tree banks. Interest in dependency grammar is growing at present, international conferences on dependency linguistics being a relatively recent development (Depling 2011, Depling 2013, Depling 2015, Depling 2017, Depling 2019).
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Dependency grammar
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Dependency vs. phrase structure
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Dependency is a one-to-one correspondence: for every element (e.g. word or morph) in the sentence, there is exactly one node in the structure of that sentence that corresponds to that element. The result of this one-to-one correspondence is that dependency grammars are word (or morph) grammars. All that exist are the elements and the dependencies that connect the elements into a structure. This situation should be compared with phrase structure. Phrase structure is a one-to-one-or-more correspondence, which means that, for every element in a sentence, there is one or more nodes in the structure that correspond to that element. The result of this difference is that dependency structures are minimal compared to their phrase structure counterparts, since they tend to contain many fewer nodes.
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Dependency grammar
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Dependency vs. phrase structure
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These trees illustrate two possible ways to render the dependency and phrase structure relations (see below). This dependency tree is an "ordered" tree, i.e. it reflects actual word order. Many dependency trees abstract away from linear order and focus just on hierarchical order, which means they do not show actual word order. This constituency (= phrase structure) tree follows the conventions of bare phrase structure (BPS), whereby the words themselves are employed as the node labels.
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Dependency grammar
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Dependency vs. phrase structure
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The distinction between dependency and phrase structure grammars derives in large part from the initial division of the clause. The phrase structure relation derives from an initial binary division, whereby the clause is split into a subject noun phrase (NP) and a predicate verb phrase (VP). This division is certainly present in the basic analysis of the clause that we find in the works of, for instance, Leonard Bloomfield and Noam Chomsky. Tesnière, however, argued vehemently against this binary division, preferring instead to position the verb as the root of all clause structure. Tesnière's stance was that the subject-predicate division stems from term logic and has no place in linguistics. The importance of this distinction is that if one acknowledges the initial subject-predicate division in syntax is real, then one is likely to go down the path of phrase structure grammar, while if one rejects this division, then one must consider the verb as the root of all structure, and so go down the path of dependency grammar.
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Dependency grammar
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Dependency grammars
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The following frameworks are dependency-based: Algebraic syntax Operator grammar Link grammar Functional generative description Lexicase Meaning–text theory Word grammar Extensible dependency grammar Universal DependenciesLink grammar is similar to dependency grammar, but link grammar does not include directionality between the linked words, and thus does not describe head-dependent relationships. Hybrid dependency/phrase structure grammar uses dependencies between words, but also includes dependencies between phrasal nodes – see for example the Quranic Arabic Dependency Treebank. The derivation trees of tree-adjoining grammar are dependency structures, although the full trees of TAG rendered in terms of phrase structure, so in this regard, it is not clear whether TAG should be viewed more as a dependency or phrase structure grammar.
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Dependency grammar
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Dependency grammars
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There are major differences between the grammars just listed. In this regard, the dependency relation is compatible with other major tenets of theories of grammar. Thus like phrase structure grammars, dependency grammars can be mono- or multistratal, representational or derivational, construction- or rule-based.
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Dependency grammar
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Representing dependencies
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There are various conventions that DGs employ to represent dependencies. The following schemata (in addition to the tree above and the trees further below) illustrate some of these conventions: The representations in (a–d) are trees, whereby the specific conventions employed in each tree vary. Solid lines are dependency edges and lightly dotted lines are projection lines. The only difference between tree (a) and tree (b) is that tree (a) employs the category class to label the nodes whereas tree (b) employs the words themselves as the node labels. Tree (c) is a reduced tree insofar as the string of words below and projection lines are deemed unnecessary and are hence omitted. Tree (d) abstracts away from linear order and reflects just hierarchical order. The arrow arcs in (e) are an alternative convention used to show dependencies and are favored by Word Grammar. The brackets in (f) are seldom used, but are nevertheless quite capable of reflecting the dependency hierarchy; dependents appear enclosed in more brackets than their heads. And finally, the indentations like those in (g) are another convention that is sometimes employed to indicate the hierarchy of words. Dependents are placed underneath their heads and indented. Like tree (d), the indentations in (g) abstract away from linear order.
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Dependency grammar
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Representing dependencies
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The point to these conventions is that they are just that, namely conventions. They do not influence the basic commitment to dependency as the relation that is grouping syntactic units.
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Dependency grammar
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Types of dependencies
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The dependency representations above (and further below) show syntactic dependencies. Indeed, most work in dependency grammar focuses on syntactic dependencies. Syntactic dependencies are, however, just one of three or four types of dependencies. Meaning–text theory, for instance, emphasizes the role of semantic and morphological dependencies in addition to syntactic dependencies. A fourth type, prosodic dependencies, can also be acknowledged. Distinguishing between these types of dependencies can be important, in part because if one fails to do so, the likelihood that semantic, morphological, and/or prosodic dependencies will be mistaken for syntactic dependencies is great. The following four subsections briefly sketch each of these dependency types. During the discussion, the existence of syntactic dependencies is taken for granted and used as an orientation point for establishing the nature of the other three dependency types.
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Dependency grammar
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Types of dependencies
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Semantic dependencies Semantic dependencies are understood in terms of predicates and their arguments. The arguments of a predicate are semantically dependent on that predicate. Often, semantic dependencies overlap with and point in the same direction as syntactic dependencies. At times, however, semantic dependencies can point in the opposite direction of syntactic dependencies, or they can be entirely independent of syntactic dependencies. The hierarchy of words in the following examples show standard syntactic dependencies, whereas the arrows indicate semantic dependencies: The two arguments Sam and Sally in tree (a) are dependent on the predicate likes, whereby these arguments are also syntactically dependent on likes. What this means is that the semantic and syntactic dependencies overlap and point in the same direction (down the tree). Attributive adjectives, however, are predicates that take their head noun as their argument, hence big is a predicate in tree (b) that takes bones as its one argument; the semantic dependency points up the tree and therefore runs counter to the syntactic dependency. A similar situation obtains in (c), where the preposition predicate on takes the two arguments the picture and the wall; one of these semantic dependencies points up the syntactic hierarchy, whereas the other points down it. Finally, the predicate to help in (d) takes the one argument Jim but is not directly connected to Jim in the syntactic hierarchy, which means that semantic dependency is entirely independent of the syntactic dependencies.
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Dependency grammar
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Types of dependencies
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Morphological dependencies Morphological dependencies obtain between words or parts of words. When a given word or part of a word influences the form of another word, then the latter is morphologically dependent on the former. Agreement and concord are therefore manifestations of morphological dependencies. Like semantic dependencies, morphological dependencies can overlap with and point in the same direction as syntactic dependencies, overlap with and point in the opposite direction of syntactic dependencies, or be entirely independent of syntactic dependencies. The arrows are now used to indicate morphological dependencies.
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Dependency grammar
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Types of dependencies
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The plural houses in (a) demands the plural of the demonstrative determiner, hence these appears, not this, which means there is a morphological dependency that points down the hierarchy from houses to these. The situation is reversed in (b), where the singular subject Sam demands the appearance of the agreement suffix -s on the finite verb works, which means there is a morphological dependency pointing up the hierarchy from Sam to works. The type of determiner in the German examples (c) and (d) influences the inflectional suffix that appears on the adjective alt. When the indefinite article ein is used, the strong masculine ending -er appears on the adjective. When the definite article der is used, in contrast, the weak ending -e appears on the adjective. Thus since the choice of determiner impacts the morphological form of the adjective, there is a morphological dependency pointing from the determiner to the adjective, whereby this morphological dependency is entirely independent of the syntactic dependencies. Consider further the following French sentences: The masculine subject le chien in (a) demands the masculine form of the predicative adjective blanc, whereas the feminine subject la maison demands the feminine form of this adjective. A morphological dependency that is entirely independent of the syntactic dependencies therefore points again across the syntactic hierarchy.
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Dependency grammar
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Types of dependencies
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Morphological dependencies play an important role in typological studies. Languages are classified as mostly head-marking (Sam work-s) or mostly dependent-marking (these houses), whereby most if not all languages contain at least some minor measure of both head and dependent marking.
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Dependency grammar
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Types of dependencies
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Prosodic dependencies Prosodic dependencies are acknowledged in order to accommodate the behavior of clitics. A clitic is a syntactically autonomous element that is prosodically dependent on a host. A clitic is therefore integrated into the prosody of its host, meaning that it forms a single word with its host. Prosodic dependencies exist entirely in the linear dimension (horizontal dimension), whereas standard syntactic dependencies exist in the hierarchical dimension (vertical dimension). Classic examples of clitics in English are reduced auxiliaries (e.g. -ll, -s, -ve) and the possessive marker -s. The prosodic dependencies in the following examples are indicated with the hyphen and the lack of a vertical projection line: The hyphens and lack of projection lines indicate prosodic dependencies. A hyphen that appears on the left of the clitic indicates that the clitic is prosodically dependent on the word immediately to its left (He'll, There's), whereas a hyphen that appears on the right side of the clitic (not shown here) indicates that the clitic is prosodically dependent on the word that appears immediately to its right. A given clitic is often prosodically dependent on its syntactic dependent (He'll, There's) or on its head (would've). At other times, it can depend prosodically on a word that is neither its head nor its immediate dependent (Florida's).
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Dependency grammar
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Types of dependencies
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Syntactic dependencies Syntactic dependencies are the focus of most work in DG, as stated above. How the presence and the direction of syntactic dependencies are determined is of course often open to debate. In this regard, it must be acknowledged that the validity of syntactic dependencies in the trees throughout this article is being taken for granted. However, these hierarchies are such that many DGs can largely support them, although there will certainly be points of disagreement. The basic question about how syntactic dependencies are discerned has proven difficult to answer definitively. One should acknowledge in this area, however, that the basic task of identifying and discerning the presence and direction of the syntactic dependencies of DGs is no easier or harder than determining the constituent groupings of phrase structure grammars. A variety of heuristics are employed to this end, basic tests for constituents being useful tools; the syntactic dependencies assumed in the trees in this article are grouping words together in a manner that most closely matches the results of standard permutation, substitution, and ellipsis tests for constituents. Etymological considerations also provide helpful clues about the direction of dependencies. A promising principle upon which to base the existence of syntactic dependencies is distribution. When one is striving to identify the root of a given phrase, the word that is most responsible for determining the distribution of that phrase as a whole is its root.
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Dependency grammar
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Linear order and discontinuities
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Traditionally, DGs have had a different approach to linear order (word order) than phrase structure grammars. Dependency structures are minimal compared to their phrase structure counterparts, and these minimal structures allow one to focus intently on the two ordering dimensions. Separating the vertical dimension (hierarchical order) from the horizontal dimension (linear order) is easily accomplished. This aspect of dependency structures has allowed DGs, starting with Tesnière (1959), to focus on hierarchical order in a manner that is hardly possible for phrase structure grammars. For Tesnière, linear order was secondary to hierarchical order insofar as hierarchical order preceded linear order in the mind of a speaker. The stemmas (trees) that Tesnière produced reflected this view; they abstracted away from linear order to focus almost entirely on hierarchical order. Many DGs that followed Tesnière adopted this practice, that is, they produced tree structures that reflect hierarchical order alone, e.g.
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Dependency grammar
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Linear order and discontinuities
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The traditional focus on hierarchical order generated the impression that DGs have little to say about linear order, and it has contributed to the view that DGs are particularly well-suited to examine languages with free word order. A negative result of this focus on hierarchical order, however, is that there is a dearth of DG explorations of particular word order phenomena, such as of standard discontinuities. Comprehensive dependency grammar accounts of topicalization, wh-fronting, scrambling, and extraposition are mostly absent from many established DG frameworks. This situation can be contrasted with phrase structure grammars, which have devoted tremendous effort to exploring these phenomena.
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Dependency grammar
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Linear order and discontinuities
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The nature of the dependency relation does not, however, prevent one from focusing on linear order. Dependency structures are as capable of exploring word order phenomena as phrase structures. The following trees illustrate this point; they represent one way of exploring discontinuities using dependency structures. The trees suggest the manner in which common discontinuities can be addressed. An example from German is used to illustrate a scrambling discontinuity: The a-trees on the left show projectivity violations (= crossing lines), and the b-trees on the right demonstrate one means of addressing these violations. The displaced constituent takes on a word as its head that is not its governor. The words in red mark the catena (=chain) of words that extends from the root of the displaced constituent to the governor of that constituent. Discontinuities are then explored in terms of these catenae. The limitations on topicalization, wh-fronting, scrambling, and extraposition can be explored and identified by examining the nature of the catenae involved.
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Dependency grammar
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Syntactic functions
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Traditionally, DGs have treated the syntactic functions (= grammatical functions, grammatical relations) as primitive. They posit an inventory of functions (e.g. subject, object, oblique, determiner, attribute, predicative, etc.). These functions can appear as labels on the dependencies in the tree structures, e.g.
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Dependency grammar
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Syntactic functions
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The syntactic functions in this tree are shown in green: ATTR (attribute), COMP-P (complement of preposition), COMP-TO (complement of to), DET (determiner), P-ATTR (prepositional attribute), PRED (predicative), SUBJ (subject), TO-COMP (to complement). The functions chosen and abbreviations used in the tree here are merely representative of the general stance of DGs toward the syntactic functions. The actual inventory of functions and designations employed vary from DG to DG.
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Dependency grammar
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Syntactic functions
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As a primitive of the theory, the status of these functions is very different from that in some phrase structure grammars. Traditionally, phrase structure grammars derive the syntactic functions from the constellation. For instance, the object is identified as the NP appearing inside finite VP, and the subject as the NP appearing outside of finite VP. Since DGs reject the existence of a finite VP constituent, they were never presented with the option to view the syntactic functions in this manner. The issue is a question of what comes first: traditionally, DGs take the syntactic functions to be primitive and they then derive the constellation from these functions, whereas phrase structure grammars traditionally take the constellation to be primitive and they then derive the syntactic functions from the constellation.
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Dependency grammar
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Syntactic functions
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This question about what comes first (the functions or the constellation) is not an inflexible matter. The stances of both grammar types (dependency and phrase structure) are not narrowly limited to the traditional views. Dependency and phrase structure are both fully compatible with both approaches to the syntactic functions. Indeed, monostratal systems, that are solely based on dependency or phrase structure, will likely reject the notion that the functions are derived from the constellation or that the constellation is derived from the functions. They will take both to be primitive, which means neither can be derived from the other.
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Voiced labiodental plosive
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Voiced labiodental plosive
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The voiced labiodental plosive or stop is a consonant sound produced like a [b], but with the lower lip contacting the upper teeth, as in [v]. This can be represented in the IPA as ⟨b̪⟩. A separate symbol that is sometimes seen, especially in Bantu linguistics, but not recognized by the IPA, is the db ligature ⟨ȸ⟩.
The voiced labiodental plosive is not known to be phonemic in any language. However, it does occur allophonically: In the Austronesian language Sika, this sound occurs as an allophone of the labiodental flap in careful pronunciation.The XiNkuna dialect of Tsonga has affricates, [p̪͡f] (voiceless labiodental affricate) and [b̪͡v] (voiced labiodental affricate).
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Voiced labiodental plosive
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Features
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Features of the "voiced labiodental stop": Its manner of articulation is occlusive, which means it is produced by obstructing airflow in the vocal tract. Since the consonant is also oral, with no nasal outlet, the airflow is blocked entirely, and the consonant is a plosive.
Its place of articulation is labiodental, which means it is articulated with the lower lip and the upper teeth.
Its phonation is voiced, which means the vocal cords vibrate during the articulation.
It is an oral consonant, which means air is allowed to escape through the mouth only.
It is a central consonant, which means it is produced by directing the airstream along the center of the tongue, rather than to the sides.
The airstream mechanism is pulmonic, which means it is articulated by pushing air solely with the intercostal muscles and diaphragm, as in most sounds.
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GALNT2
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GALNT2
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Polypeptide N-acetylgalactosaminyltransferase 2 is an enzyme that in humans is encoded by the GALNT2 gene.This gene encodes polypeptide N-acetylgalactosaminyltransferase 2, a member of the GalNAc-transferases family. This family transfers an N-acetyl galactosamine to the hydroxyl group of a serine or threonine residue in the first step of O-linked oligosaccharide biosynthesis. The localization site of this particular enzyme is preponderantly the trans-Golgi. Individual GalNAc-transferases have distinct activities, and initiation of O-glycosylation in a cell is regulated by a repertoire of GalNAc-transferases.
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Church bell
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Church bell
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A church bell in Christian architecture is a bell which is rung in a church for a variety of religious purposes, and can be heard outside the building. Traditionally they are used to call worshippers to the church for a communal service, and to announce the fixed times of daily Christian prayer, called the canonical hours, which number seven and are contained in breviaries. They are also rung on special occasions such as a wedding, or a funeral service. In some religious traditions they are used within the liturgy of the church service to signify to people that a particular part of the service has been reached. The ringing of church bells, in the Christian tradition, is also believed to drive out demons.The traditional European church bell (see cutaway drawing) used in Christian churches worldwide consists of a cup-shaped metal resonator with a pivoted clapper hanging inside which strikes the sides when the bell is swung. It is hung within a steeple or belltower of a church or religious building, so the sound can reach a wide area. Such bells are either fixed in position ("hung dead") or hung from a pivoted beam (the "headstock") so they can swing to and fro. A rope hangs from a lever or wheel attached to the headstock, and when the bell ringer pulls on the rope the bell swings back and forth and the clapper hits the inside, sounding the bell. Bells that are hung dead are normally sounded by hitting the sound bow with a hammer or occasionally by a rope which pulls the internal clapper against the bell.
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Church bell
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Church bell
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A church may have a single bell, or a collection of bells which are tuned to a common scale. They may be stationary and chimed, rung randomly by swinging through a small arc, or swung through a full circle to enable the high degree of control of English change ringing.
Before modern communications, church bells were a common way to call the community together for all purposes, both sacred and secular.
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Church bell
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Uses and traditions
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Call to prayer Oriental Orthodox Christians, such as Copts and Indians, use a breviary such as the Agpeya and Shehimo to pray the canonical hours seven times a day while facing in the eastward direction; church bells are tolled, especially in monasteries, to mark these seven fixed prayer times.In Christianity, some churches ring their church bells from belltowers three times a day, at 9 am, 12 pm and 3 pm to summon the Christian faithful to recite the Lord's Prayer; the injunction to pray the Lord's prayer thrice daily was given in Didache 8, 2 f., which, in turn, was influenced by the Jewish practice of praying thrice daily found in the Old Testament, specifically in Psalm 55:17, which suggests "evening and morning and at noon", and Daniel 6:10, in which the prophet Daniel prays thrice a day. The early Christians thus came to pray the Lord's Prayer at 9 am, 12 pm and 3 pm.
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Church bell
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Uses and traditions
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Many Catholic Christian churches ring their bells thrice a day, at 6 am, 12 pm, and 6 pm to call the faithful to recite the Angelus, a prayer recited in honour of the Incarnation of God.Some Protestant Christian Churches ring church bells during the congregational recitation of the Lord's Prayer, after the sermon, in order to alert those who are unable to be present to "unite themselves in spirit with the congregation".In many historic Christian Churches, church bells are also rung on All Hallows' Eve, as well as during the processions of Candlemas and Palm Sunday; the only time of the Christian Year when church bells are not rung include Maundy Thursday through the Easter Vigil. The Christian tradition of the ringing of church bells from a belltower is analogous to the Islamic tradition of the adhan from a minaret.
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Church bell
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Uses and traditions
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Call to worship Most Christian denominations ring church bells to call the faithful to worship, signalling the start of a mass or service of worship.
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Church bell
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Uses and traditions
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In the United Kingdom predominantly in the Anglican church, there is a strong tradition of change ringing on full-circle tower bells for about half an hour before a service. This originated from the early 17th century when bell ringers found that swinging a bell through a large arc gave more control over the time between successive strikes of the clapper. This culminated in ringing bells through a full circle, which let ringers easily produce different striking sequences; known as changes.
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Church bell
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Uses and traditions
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Exorcism of demons In Christianity, the ringing of church bells is traditionally believed to drive out demons and other unclean spirits. Inscriptions on church bells relating to this purpose of church bells, as well as the purpose of serving as a call to prayer and worship, were customary, for example "the sound of this bell vanquishes tempests, repels demons, and summons men". Some churches have several bells with the justification that "the more bells a church had, the more loudly they rang, and the greater the distance over which they could be heard, the less likely it was that evil forces would trouble the parish." Funeral and memorial ringing The ringing of a church bell in the English tradition to announce a death is called a death knell. The pattern of striking depended on the person who had died; for example in the counties of Kent and Surrey in England it was customary to ring three times three strokes for a man and three times two for a woman, with a varying usage for children. The age of the deceased was then rung out. In small settlements this could effectively identify who had just died.There were three occasions surrounding a death when bells could be rung. There was the "Passing Bell" to warn of impending death, the second the Death Knell to announce the death, and the last was the "Lych Bell", or "Corpse Bell" which was rung at the funeral as the procession approached the church. This latter is known today as the Funeral toll.
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Church bell
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Uses and traditions
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A more modern tradition where there are full-circle bells is to use "half-muffles" when sounding one bell as a tolled bell, or all the bells in change-ringing. This means a leather muffle is placed on the clapper of each bell so that there is a loud "open" strike followed by a muffled strike, which has a very sonorous and mournful effect. The tradition in the United Kingdom is that bells are only fully muffled for the death of a sovereign. A slight variant on this rule occurred in 2015 when the bones of Richard III of England were interred in Leicester Cathedral 532 years after his death.
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Church bell
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Uses and traditions
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Sanctus bells The term "Sanctus bell" traditionally referred to a bell suspended in a bell-cot at the apex of the nave roof, over the chancel arch, or hung in the church tower, in medieval churches. This bell was rung at the singing of the Sanctus and again at the elevation of the consecrated elements, to indicate to those not present in the building that the moment of consecration had been reached. The practice and the term remain in common use in many Anglican churches.
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Church bell
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Uses and traditions
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Within the body of a church the function of a sanctus bell can also be performed by a small hand bell or set of such bells (called altar bells) rung shortly before the consecration of the bread and wine into the Body and Blood of Christ and again when the consecrated elements are shown to the people. Sacring rings or "Gloria wheels" are commonly used in Catholic churches in Spain and its former colonies for this purpose.
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Church bell
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Uses and traditions
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Orthodox Church In the Eastern Orthodox Church there is a long and complex history of bell ringing, with particular bells being rung in particular ways to signify different parts of the divine services, Funeral tolls, etc. This custom is particularly sophisticated in the Russian Orthodox Church. Russian bells are usually stationary, and are sounded by pulling on a rope that is attached to the clapper so that it will strike the inside of the bell.
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Church bell
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Uses and traditions
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Victory Celebration The noon church bell tolling in Europe has a specific historical significance that has its roots in the Siege of Belgrade by the Ottomans in 1456. Initially, the bell ringing was intended as a call to prayer for the victory of the defenders of Belgrade. However, because in many European countries the news of victory arrived before the order for prayer, the ringing of the church bells was believed to be in celebration of the victory. As a result, the significance of noon bell ringing is now a commemoration of John Hunyadi's victory against the Turks.
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Church bell
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Uses and traditions
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Other uses Clock chimes Some churches have a clock chime which uses a turret clock to broadcast the time by striking the hours and sometimes the quarters. A well-known musical striking pattern is the Westminster Quarters. This is only done when the bells are stationary, and the clock mechanism actuates hammers striking on the outside of the sound-bows of the bells. In the cases of bells which are normally swung for other ringing, there is a manual lock-out mechanism which prevents the hammers from operating whilst the bells are being rung.
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Church bell
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Uses and traditions
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Warning In World War II in Great Britain, all church bells were silenced, to ring only to inform of an invasion by enemy troops. However this ban was lifted temporarily in 1942 by order of Winston Churchill. Starting with Easter Sunday, April 25, 1943, the Control of Noise (Defence) (No. 2) Order, 1943, allowed that church bells could be rung to summon worshippers to church on Sundays, Good Friday and Christmas Day. On May 27, 1943, all restrictions were removed.In the 2021 German floods it was reported that church bells were rung to warn inhabitants of coming floods. In Beyenburg in Wuppertal the last friar of Steinhaus Abbey rang the storm bells after other systems failed. Some church bells are being used in England for similar purposes.
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Church bell
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Design and ringing technique
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Christian church bells have the form of a cup-shaped cast metal resonator with a flared thickened rim, and a pivoted clapper hanging from its centre inside. It is usually mounted high in a bell tower on top of the church, so it can be heard by the surrounding community. The bell is suspended from a headstock which can swing on bearings. A rope is tied to a wheel or lever on the headstock, and hangs down to the bell ringer. To ring the bell, the ringer pulls on the rope, swinging the bell. The motion causes the clapper to strike the inside of the bell rim as it swings, thereby sounding the bell. Some bells have full-circle wheels, which is used to swing the bell through a larger arc, such as in the United Kingdom where full- circle ringing is practised.
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Church bell
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Design and ringing technique
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Bells which are not swung are "chimed", which means they are struck by an external hammer, or by a rope attached to the internal clapper, which is the tradition in Russia.
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Church bell
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Blessing of bells
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In some churches, bells are often blessed before they are hung.
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Church bell
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Blessing of bells
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In the Roman Catholic Church the name Baptism of Bells has been given to the ceremonial blessing of church bells, at least in France, since the eleventh century. It is derived from the washing of the bell with holy water by the bishop, before he anoints it with the "oil of the infirm" without and with chrism within; a fuming censer is placed under it and the bishop prays that these sacramentals of the Church may, at the sound of the bell, put the demons to flight, protect from storms, and call the faithful to prayer.
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Church bell
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History
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Before the introduction of church bells into the Christian Church, different methods were used to call the worshippers: playing trumpets, hitting wooden planks, shouting, or using a courier. In AD 604, Pope Sabinian officially sanctioned the usage of bells. These tintinnabula were made from forged metal and did not have large dimensions. Larger bells were made at the end of the 7th and during the 8th century by casting metal originating from Campania. The bells consequently took the name of campana and nola from the eponymous city in the region. This would explain the apparently erroneous attribution of the origin of church bells to Paulinus of Nola in AD 400. By the early Middle Ages, church bells became common in Europe. They were first common in northern Europe, reflecting Celtic influence, especially that of Irish missionaries. Before the use of church bells, Greek monasteries would ring a flat metal plate (see semantron) to announce services. The signa and campanae used to announce services before Irish influence may have been flat plates like the semantron rather than bells. The oldest surviving circle of bells in Great Britain is housed in St Lawrence Church, Ipswich.
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Church bell
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In literature
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The evocative sound of church bells has inspired many writers, both in poetry and prose. One example is an early poem by the English poet Letitia Elizabeth Landon entitled simply, Bells. She returned to the subject towards the end of her life in Fisher's Drawing Room Scrap Book, 1839 with The Village Bells., a poetical illustration to a picture by J. Franklin. How Soft the Music of those Village Bells.
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Church bell
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Controversies about noise
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The sound of church bells is capable of causing noise that interrupts or prevents people from sleeping. A 2013 study from the Swiss Federal Institute of Technology in Zurich found that "An estimated 2.5-3.5 percent of the population in the Canton of Zurich experiences at least one additional awakening per night due to church bell noise." It concluded that "The number of awakenings could be reduced by more than 99 percent by, for example, suspending church bell ringing between midnight and 06 h in the morning", or by "about 75 percent (...) by reducing the sound-pressure levels of bells by 5 dB."In the Netherlands, there have been lawsuits about church bell noise pollution experienced by nearby residents. The complaints are usually, but not always, raised by new local residents (or tourists who spend the night in the neighbourhood) who are not used to the noise at night or during the day. Local residents who had been used to it for longer usually retort that the newcomers "should have known this before they moved here" and that the ringing bells "belong to the local tradition", which sometimes goes back more than a hundred years.
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Ludomusicology
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Ludomusicology
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Ludomusicology (also called video game music studies or video game music research) is a field of academic research and scholarly analysis focusing on video game music, understood as the music found in video games and in related contexts. It is closely related to the fields of musicology and interactive and games audio research, and game music and audio are sometimes studied as a united phenomenon. Ludomusicology is also related to the field of game studies, as music is one element of the wider video game text and some theories on video game functions are directly relevant to music.
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Ludomusicology
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Ludomusicology
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Whereas the overarching areas of interactive and game audio research and game studies are highly interdisciplinary (ranging from interface research, neurological research, psychology and informatics to sound studies, cultural studies and media studies), ludomusicology as a subfield has been mainly driven by musicologists (albeit with an openness to interdisciplinary inquiry). Ludomusicology not only deals with music in games and music games as its subject matter, but is also interested in the ways in which games and their music have become subjects of playful engagement themselves, e.g. within the frame of fancultural practices. Additionally and more generally, game music challenges the ways in which we think about music, and subsequently how we study it.The number of anthologies and monographs dealing with the specific subject of game music and music in game culture is steadily increasing. The ludomusicological community now organizes conferences, runs subgroups within the musicological societies, and engages in discourse with scholarly colleagues in a wide range of related fields.
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Ludomusicology
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History
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Academic research on video game music began in the late 1990s, and developed through the mid 2000s. Early research on the topic often involved historical studies of game music, or comparative studies of video game music and film music (see, for instance, Zach Whalen's article "Play Along – An Approach to Videogame Music" which includes both). The study of video game music is also known by some as "ludomusicology" – a portmanteau of "ludology" (the study of games and gameplay) and "musicology" (the study and analysis of music) – a term coined independently by Guillaume Laroche and Roger Moseley.A prominent figure in early video game music and audio research is Karen Collins, who is associate professor at the University of Waterloo and Canada Research Chair in Interactive Audio at the University of Waterloo Games Institute. Her monograph Game Sound: An Introduction to the History, Theory and Practice of Video Game Music and Sound Design (MIT Press 2008) is considered a seminal work in the field, and was influential in the subsequent development of video game music studies.
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Ludomusicology
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History
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In 2012, the Ludomusicology Research Group held its inaugural conference at the University of Oxford. This was the first conference in the world to be focused specifically on video game music. In 2014 the inaugural North American Conference on Video Game Music was held at Youngstown State University. Both conferences have since been held annually, at varying locations in Europe and North America respectively.
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Ludomusicology
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History
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In late 2016, the Society for the Study of Sound and Music in Games (SSSMG) was launched by the Ludomusicology Research Group in conjunction with the organisers of the North American Conference on Video Game Music and the Audio Mostly conference. The SSSMG is the first international society dedicated to the study of video game music. In September 2017, the SSSMG announced the planned launch of a new journal dedicated to video game music and sound research, the Journal of Sound and Music in Games.
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Ludomusicology
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Areas of enquiry
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Ludomusicology examines any and all aspects of video game music and audio, some of which are described in brief here.
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Ludomusicology
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Areas of enquiry
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Interactivity Interactivity is one of the major differentiating qualities of video game music, distinguishing it from other screen media music through the incorporation of player actions. In interactive gameplay, the sound and music played by the game can respond to the actions of the player within the game. Furthermore, as video games frequently feature non-linear or multi-linear timelines, their music can be similarly multi-threaded in both its form and its experience.: 3–4 Because each player takes an independently-chosen path through the game, any player's experience of a game's music will be different (considered as a whole) to any other player's experience from the same game, even though constructed from the same basic elements. Therefore, the intent and output of the composer and the music's effect on the player (which similarly varies from player to player) must both be considered during analysis.A related concept to that of interactivity is that of immersion, which considers the ability of a video game to draw the player into a deep engagement with the game's diegetic space. Isabella van Elferen has developed a model of video game music immersion called "the ALI model", which understands player immersion to be a confluence of "musical affect, musical literacy and musical interaction": Affect: "personal investment in a given situation through memory, emotion and identification" Literacy: "fluency in hearing and interpreting... music through the fact of our frequent exposure to [it]", which builds on such literacy from other musical media Interaction: the player's reactions to music, and vice versa.
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Ludomusicology
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Areas of enquiry
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Technology Historical studies of video game music usually incorporate examinations of game music technology. Technological limitations of audio chips in early consoles and computer systems were, in many ways, instrumental in shaping the development of both the functions and aesthetics of game music. For example, Karen Collins describes how the Television Interface Adapter in the Atari 2600 created tones that could be out of tune by up to half a semitone; this led to minimal music in games for this platform, and substantial modifications to the music of ported games.: 21–23 Similarly, Melanie Fritsch observes the relative freedoms afforded to game composers by CD audio (higher quality, though limited to 79.8 minutes) and later MP3 (similar quality to CD audio but with compression minimising length restrictions), while also noting the challenges presented by writing increasingly detailed music to accompany hundreds of hours of gameplay. Another technology that has attracted significant academic attention is iMUSE, a MIDI-based system developed by LucasArts that allowed dynamic and smooth musical transitions, which were triggered by game conditions but which would occur at musically expedient (pre-designated) positions in the soundtrack.: 51–57 Ludomusicology also investigates muso-technological practices in fields surrounding video games. For example, scholarly attention is turning to chiptune, which is the creation of music using old video game or sound chip hardware (a definition which is sometimes broadened to include the imitation of the resulting aesthetic).
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Ludomusicology
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Areas of enquiry
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Composition Ludomusicology examines the composition of video game music, both in relation to and as distinct from other forms of music composition. Studies of game music compositional processes are often contributed by active composers and industry practitioners (for example, Winifred Phillips's book A Composer's Guide to Game Music, and Stephen Baysted's chapter "Palimpsest, Pragmatism and the Aesthetics of Genre Transformation: Composing the Hybrid Score to Electronic Arts' Need for Speed Shift 2: Unleashed"). A significant distinction of video game music composition is the need to incorporate the player's interactivity into the compositional process, and particularly as part of the negotiation of engagement and immersion.: 35–36 Composition is also at the nexus of creative potential and technological possibility, and throughout the development of game music (and particularly in its early phases) this has had significant effects on both compositional processes and game music aesthetics.: 35 Music video games Music video games, which use music as part of a dominant gameplay mechanism, are a focus of many ludomusicological studies. The clear relationship between music and gameplay in games like the Guitar Hero and Rock Band series facilitates the study of performance and performativity within gameplay, and provokes questions of musical ideology, performance practice and multimedia pedagogy. Kiri Miller writes that music video games feature a smaller disparity between the actions of player and avatar than is usually present in video games, and that this can encourage heightened levels of physical and musical engagement. David Roesner, Anna Paisley, and Gianna Cassidy have examined these phenomena within the classroom context, observing that music video games can inspire not only musical creativity, but the positive self-perception of musicality in students; they suggest that such effects can be used to encourage student engagement and development within both musical and non-musical curricula.
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Ludomusicology
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Areas of enquiry
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Relationship to music in other screen media Because video games are (usually) screen-based media, there are strong links between the study of game music and the study of music in other screen-based media (like film and television). Concepts such as diegesis and acousmatics, which originate in film and film audio studies, are broadly applicable to video game music analyses, often with minimal adjustment. Furthermore, there are similarities between video game and film music techniques as varying stages throughout video game music history. For example, Neil Lerner notes a relationship between music in early/silent cinema and game music aesthetics from the 1970s onwards, on the basis of "largely nonverbal communication system[s]" and "continuous musical accompaniment". Similarly, Gregor Herzfeld compares the use of high energy music in Gran Turismo to the use of rock music in action films like The Fast and the Furious, due to associations with risky and/or exciting behavior.However, it is also well noted within ludomusicological discourse that video games are very different media to film and television due to the player's interaction. Consequently, the application of concepts like diegesis does require a nuanced approach that takes the peculiarities of the video game medium into account. For example, Collins observes that linear approaches to musical analysis (such as the observation of synchronicity between musical and visual cues) fail to address the non-linear timescales that are typical of video games.: 3–4 This forms a basis of Collins's reiteration of a warning by video game theorists against "theoretical imperialism".: 5 Research methods Several academics have written about the research methods involved in ludomusicology. One of the more comprehensive of these studies is found in Tim Summers's book Understanding Video Game Music, in which Summers describes the process of "analytical play", wherein the analyst is "deliberately subverting the game's expectations of the player's actions.... At moments when game rules are tested, the architecture is often clearest. By playing experimentally (or using 'analytical play') to investigate the musical system in the game and comparing multiple play sessions, the musical mechanics of the game programming can be divined".: 35 Summers places this analytical method alongside more conventional sources of research data, both from inside the game (e.g., programmatic and musical information, the latter of which frequently involves the application of conventional musicology and music theory to the video game music text) and from texts and communities surrounding the game.: 34–50 In her monograph Performing Bytes. Musikperformances der Computerspielkultur, Melanie Fritsch proposes an overarching ludomusicological theoretical framework, building on a subject-specific concept of performance that emphasizes the relationship between the two dimensions of performance ("ausführen" and "aufführen"). This concept is used as the initial step for developing an extended vocabulary on games and computer games, rooted in the relevant discourse of Game Studies. On that basis, a game performance theory is developed that allows to analyze gameplaying as a form of performance. In the next section an introduction to the theorization about "Music as Performance", as conducted by researchers such as Nicholas Cook, Carolyn Abbate, Philip Auslander and Christopher Small, is provided. Building on an understanding of music as a performative and playful process a terminological framework is developed that allows to analyze both games and music as playful performative practices, including questions of embodiment and socio-cultural aspects. The theoretical model is applied in six case studies to demonstrate how music as a design element in games, music games, and participatory musical practices in computer game culture can be fruitfully analyzed with this terminology.
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Ludomusicology
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Groups and Conferences
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Ludomusicology Research Group The Ludomusicology Research Group is an inter-university research organisation focusing on the study of music in games, music games and music in video game culture, composed of five researchers: Melanie Fritsch, Andra Ivănescu, Michiel Kamp, Tim Summers, and Mark Sweeney. Together they organise an annual international conference held in the UK or mainland Europe. The Ludo2018 held in Leipzig, Germany, in April 2018, was the biggest Ludo-conference so far, attracting more than 80 participants from all over the world. The group was originally founded by Kamp, Summers and Sweeney in August 2011, who have also edited a collection of essays based around the study of game sound entitled Ludomusicology: Approaches to Video Game Music, published in July 2016. They also edited a double special issue of The Soundtrack and initiated a new book series called Studies in Game Sound and Music in 2017. In September 2016, Tim Summers' book Understanding Video Game Music was published by Cambridge University Press. Fritsch officially joined the group in 2016. She had edited the 2nd issue of the online journal ACT - Zeitschrift für Musik und Performance, published in July 2011 that included ludomusicological contributions written by Tim Summers, Steven Reale and Jason Brame. She had been a regular at the conferences since 2012 and published several book chapters on the topic. Ivănescu joined the group in 2021. Her monograph Popular Music and the Nostalgia Video Game was published by Palgrave Macmillan in 2019. Whereas Ivănescu, Kamp, Summers, and Sweeney have a background in Musicology, Fritsch has her background in Performance Studies.
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Ludomusicology
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Groups and Conferences
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North American Conference on Video Game Music (NACVGM) The North American Conference on Video Game Music (NACVGM) is an international conference on video game music held annually in North America since 2014. The first conference was organised by Neil Lerner, Steven Reale, and William Gibbons.
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Ludomusicology
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Groups and Conferences
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Society for the Study of Sound and Music in Games (SSSMG) In late 2016 the Society for the Study of Sound and Music in Games (SSSMG) was launched by the Ludomusicology Research Group in conjunction with the organisers of the North American Conference on Video Game Music and the Audio Mostly conference. The SSSMG has the aim of bringing together both practitioners and researchers from across the globe in order to develop the field's understanding of sound and video game music and audio. Its initial focus is the use of its website as a "hub" for communication and resource centralisation, including a video game music research bibliography (a project initially begun by the Ludomusicology Research Group).In 2018, the Journal of Sound and Music in Games was launched in collaboration with University of California Press. JSMG is a specialist journal for scholars and industry practitioners of video game music and sound. While the core audience is game music scholars, the interdisciplinary nature of the field means that the journal encourages submissions from authors who identify primarily with other fields (such as game studies, computer science, educational science, performance studies etc.), as well as practitioners (game music composers, sound designers etc.). While JSMG primarily focuses on video games, studies of music and/or sound in any form of game (for example, sports, historical games predating video games, and so on) are explicitly welcome. JSMG's principal focus is original research articles, supplemented from time-to-time by a range of other content including review articles surveying important subjects, reviews of pertinent books and games, communications with responses, and interviews. The first issue is scheduled in early 2020.
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Ludomusicology
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Groups and Conferences
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AMS Ludomusicology Study Group The Ludomusicology Study Group of the American Musicological Society was founded in 2015 and "is dedicated to facilitating academic research on music interactive media", including holding a panel on video game music as part of the annual meetings of the Society.
Ludomusicology Society of Australia (LSA) The Ludomusicology Society of Australia was launched in April 2017, during the Ludo2017 conference in Bath, UK; it aims to "offer a centralised and local professional body nurturing game music studies for academics, people in industry and game music fans alike in the Australasian region."
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Smart shop
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Smart shop
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A smart shop (or smartshop) is a retail establishment that specializes in the sale of psychoactive substances, usually including psychedelics, as well as related literature and paraphernalia. The name derives from the name "smart drugs", a class of drugs and food supplements intended to affect cognitive enhancements which are often sold in smart shops.
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Smart shop
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The rise of anonymous smart shops
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Some governments do not tolerate smart shops in any form as a part of their crime prevention. For example, the Government of the Kingdom of Sweden with its zero tolerance drug policy, does not accept physical smart shops and has shut down every known Swedish online smart shop that have been selling pure research chemicals on the visible Web. To circumvent this the usage of anonymous marketplaces through the Tor network has taken over since the establishment of Silk Road, which in contrast took the FBI two and a half years to take down for one month.
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Smart shop
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Typical products specialization
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Smart drugs Smart shops (often webshops) offer prescription-free pharmacy products such as Ritalin, Adderall, and modafinil, for example.
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Smart shop
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Typical products specialization
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Psychedelics, dissociatives, and deliriants Traditional entheogens Smart shops are best known in practice for selling whatever psychedelics, dissociatives, entactogens and deliriants local law permits. In the Netherlands, which is home to most of the smart shops in Europe, this includes Salvia divinorum, Amanita muscaria, Peyote, San Pedro cactus, Tabernanthe iboga, and various ingredients for Ayahuasca preparations. As of 1 December 2008, magic mushrooms are under stricter control in the Netherlands. Those new controls are quite controversial, because the list of banned mushrooms also contains species that have no psychoactive substances. Magic Mushroom spore prints and grow boxes are still available over the counter in the Netherlands. Psilocybin is not included in the ban and continues to be sold in smart shops nationwide in truffle form.
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Smart shop
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Typical products specialization
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The decline of designer drugs Smart shops in various countries have been known in the past to sell designer drugs: that is, synthetic substances that were not (yet) illegal. The sale of synthetic drugs not explicitly approved as food, supplements or medicines is illegal in some of them. For example, in the Netherlands it is dealt with by the relatively benign machinery of the Warenautoriteit (Commodities Authority) rather than in criminal law, as would be the case with controlled substances.
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Smart shop
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Typical products specialization
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Yet, this has made it effectively impossible to sell them in a formal retail setting, even if their production and possession is entirely legitimate. Smart shops have attempted no further marketing of synthetics since they tried to sell methylone as a "room odorizer" but were ultimately forced to pull it from their shelves in 2004, though it can still be obtained under the counter in some shops.
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Smart shop
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Typical products specialization
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Drug paraphernalia Smart shops sell many products that can be seen as complement goods to psychoactive drugs, including illegal ones. In the Netherlands, which has no drug paraphernalia laws, this is entirely legal. In particular, the sales of literature about illegal drugs or their manufacture is rarely criticized and protected by a traditional concern for free speech in local law and custom that is more pronounced than in other European nations.
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Smart shop
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Typical products specialization
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Many of the paraphernalia and complements sold in smart shops reduce, in one way or another, the harm associated with illegal drugs. For instance, reagent kits for testing the purity of ecstasy can be essential now that tablets named ecstasy can in practice contain just about anything, and often do not, in fact, contain MDMA at all. Supplements of vitamins and amino acids have been developed to mitigate specifically the damage of certain illegal drugs. Tryptophan and 5-hydroxy-tryptophan, for instance, can be used to help the body replenish serotonin levels in the brain after the use of MDMA, and vitamin supplements are appropriate for users of stimulants such as amphetamine. Vitamin B12 is depleted by recreational use of nitrous oxide, and is thereby useful.
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Smart shop
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Typical products specialization
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Smart shop is distinguished from head shops found in many countries. Head shops provide only paraphernalia, whereas smart shops usually sell at least some actual drugs. The term head shop is more common in the UK, though many British head shops sold magic mushrooms until July 2005 when the Government introduced a complete ban on magic mushrooms, putting them in the same category as heroin and crack cocaine. Many of the British head shops still sell a range of other legal highs.
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Smart shop
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Education and information
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Smart shops have become a natural source of information about the drugs they sell. They commonly provide instruction leaflets similar to the package inserts distributed with prescription drugs, which contain information on contra-indications, side effects, and the importance of set and setting. In the Netherlands, there is relatively little formal regulation of the smart shop industry, but the natural concentration of expertise about a relatively exotic range of products in combination with the realization that closer public scrutiny and regulation are always lurking in the background have caused the smart shops to organize into an industry association that, among other things, promotes the spread of information about its wares.
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Smart shop
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Legality
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The Netherlands Legally, smart shops operate under a decision of the Hoge Raad (Supreme Court) that has declared that unprepared mushrooms and cacti are not considered "preparations" of the substances they contain, and are therefore not banned under the Opium Act or international law even if their active ingredients are.
There are some shops from the Netherlands that operate as both a smart shop and a head shop on an international level. Customers are expected to accept the responsibility to inform themselves about the local laws, import and custom regulations before ordering and to certify that the import to their country of the products ordered is legal.
As of December 1, 2008, the sale of magic mushrooms was subject to tighter control in the Netherlands.
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Smart shop
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Legality
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This legal regime is markedly different from the one that applies to cannabis products. Those are formally illegal under the Opium Act and international law, which explicitly bans the plant rather than the cannabinoids in it. Cannabis products such as marijuana and hashish can be sold and possessed only pursuant to a web of executive orders more-or-less silently assented to by parliament. The sale of magic mushrooms, on the other hand, was entirely legal and subject only to the common regulation of foodstuffs by the Warenautoriteit (Commodities Authority).
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Smart shop
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Legality
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Republic of Ireland In the Republic of Ireland, there was a sharp rise in Smart shops around the Celtic Tiger era, however, given new government legislations against psychoactive substances, Smart shops that do still operate in the Republic Of Ireland have become shops for paraphernalia and growing equipment, more comparable to a Head Shop.
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Smart shop
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Legality
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UK As with UK based head shops, both paraphernalia and "legal highs" are available from these stores, such as Salvia Divinorum-based products designed to simulate illegal drug highs such as those experienced through the use of amphetamine [speed], methamphetamine, and psychedelics [psilocybin]. Magic mushrooms were available until the government closed a loophole, effectively banning the sale of raw or prepared magic mushrooms in January 2006.
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Smart shop
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Legality
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Since the passing of the Psychoactive Substances Act 2016, the sale of any chemical substance which alters or affects mental functioning in any way is illegal. This has effectively rendered the term "smartshop" obsolete in the UK.
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Smart shop
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Legality
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Portugal In Portugal, prior to March 2013, the drug laws were very liberal, and several smartshops were opened. A chain store, called Magic Mushroom, emerged as the market leader. Shops in Portugal still sell all type of herbal incense and plant feeders. In March 2013, the Portuguese Government enacted a law making it illegal to sell psychoactive drugs, thus ending the smartshop business in the country.
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Composition of electronic cigarette aerosol
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Composition of electronic cigarette aerosol
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The chemical composition of the electronic cigarette aerosol varies across and within manufacturers. Limited data exists regarding their chemistry. However, researchers at Johns Hopkins University analyzed the vape clouds of popular brands such as Juul and Vuse, and found "nearly 2,000 chemicals, the vast majority of which are unidentified."The aerosol of e-cigarettes is generated when the e-liquid comes in contact with a coil heated to a temperature of roughly 100–250 °C (212–482 °F) within a chamber, which is thought to cause pyrolysis of the e-liquid and could also lead to decomposition of other liquid ingredients. The aerosol (mist) produced by an e-cigarette is commonly but inaccurately called vapor. E-cigarettes simulate the action of smoking, but without tobacco combustion. The e-cigarette aerosol looks like cigarette smoke to some extent. E-cigarettes do not produce aerosol between puffs. The e-cigarette aerosol usually contains propylene glycol, glycerin, nicotine, flavors, aroma transporters, and other substances. The levels of nicotine, tobacco-specific nitrosamines (TSNAs), aldehydes, metals, volatile organic compounds (VOCs), flavors, and tobacco alkaloids in e-cigarette aerosols vary greatly. The yield of chemicals found in the e-cigarette aerosol varies depending on, several factors, including the e-liquid contents, puffing rate, and the battery voltage.Metal parts of e-cigarettes in contact with the e-liquid can contaminate it with metals. Heavy metals and metal nanoparticles have been found in tiny amounts in the e-cigarette aerosol. Once aerosolized, the ingredients in the e-liquid go through chemical reactions that form new compounds not previously found in the liquid. Many chemicals, including carbonyl compounds such as formaldehyde, can inadvertently be produced when the nichrome wire (heating element) that touches the e-liquid is heated and chemically reacted with the liquid. Propylene glycol-containing liquids produced the most amounts of carbonyls in e-cigarette vapors, while in 2014 most e-cigarettes companies began using water and glycerin instead of propylene glycol for vapor production.Propylene glycol and glycerin are oxidized to create aldehydes that are also found in cigarette smoke when e-liquids are heated and aerosolized at a voltage higher than 3 V. Depending on the heating temperature, the carcinogens in the e-cigarette aerosol may surpass the levels of cigarette smoke. Reduced voltage e-cigarettes generate very low levels of formaldehyde. A Public Health England (PHE) report found "At normal settings, there was no or negligible formaldehyde release." However, this statement was contradicted by other researchers in a 2018 study. E-cigarettes can emit formaldehyde at high levels (between five and 15 times higher than what is reported for cigarette smoke) at moderate temperatures and under conditions that have been reported to be non-averse to users. As e-cigarette engineering evolves, the later-generation and "hotter" devices could expose users to greater amounts of carcinogens.
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Composition of electronic cigarette aerosol
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Background
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There is a debate on the composition, and the subsequent health burden, of tobacco smoke compared with electronic cigarette vapor. Tobacco smoke is a complex, dynamic and reactive mixture containing around 5,000 chemicals. In 2021, researchers at Johns Hopkins University analyzed the vape aerosols of popular brands such as Juul and Vuse, and found "nearly 2,000 chemicals, the vast majority of which are unidentified." E-cigarette vapor contains many of the known harmful toxicants found in traditional cigarette smoke, such as formaldehyde, cadmium, and lead, though usually at a reduced percentage.There are substances in e-cigarette vapor that are not found in tobacco smoke. Researchers are part of the conflict, with some opposing and others supporting of e-cigarette use. The public health community is divided, even polarized, over how the use of these devices will impact the tobacco epidemic. Proponents of e-cigarettes think that these devices contain merely "water vapour" in the e-cigarette aerosols, but this view is refuted by the evidence.
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Composition of electronic cigarette aerosol
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Particulate matter
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Pathogens E-liquid used in e-cigarettes have been found to be contaminated with fungi and bacteria. Nicotine-containing e-liquids are extracted from tobacco that may contain impurities. Tobacco-specific impurities such as cotinine, nicotine-N'-oxides (cis and trans isomers), and beta-nornicotyrine are believed to be the result of bacterial action or oxidation during the extracting of nicotine from tobacco.
Re-used vapes, and vape sharing Bacterial pneumonia.
Fungal pneumonia Viral pneumonia from vape sharing.SARS-CoV-2: Shared vaping devices are linked to COVID-19.
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Composition of electronic cigarette aerosol
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Particulate matter
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Chemicals E-cigarette components include a mouthpiece, a cartridge (liquid storage area), a heating element/atomizer, a microprocessor, a battery, and some of them have a LED light at the tip. They are disposable or reusable devices. Disposable ones are not rechargeable and typically cannot be refilled with a liquid. There are a diverse range of disposable and reusable devices, resulting in broad variations in their structure and their performance. Since many devices include interchangeable components, users have the ability to alter the nature of the inhaled vapor.For the majority of e-cigarettes many aspects are similar to their traditional counterparts such as giving nicotine to the user. E-cigarettes simulates the action of smoking, with a vapor that looks like cigarette smoke to some extent. E-cigarettes do not involve tobacco combustion, and they do not produce vapor between puffs. They do not produce sidestream smoke or sidestream vapor.Vapor production basically entails preprocessing, vapor generation, and postprocessing. First, the e-cigarette is activated by pressing a button or other devices switch on by an airflow sensor or other type of trigger sensor. Then, power is released to an LED, other sensors, and other parts of the device, and to a heating element or other kind of vapor generator. Subsequently, the e-liquid flows by capillary action to the heating element or other devices to the e-cigarette vapor generator. Second, the e-cigarette vapor processing entails vapor generation.The e-cigarette vapor is generated when the e-liquid is vaporized by the heating element or by other mechanical methods. The last step of vapor processing happens as the e-cigarette vapor passes through the main air passage to the user. For some advanced devices, before inhaling, the user can adjust the heating element temperature, air flow rate or other features. The liquid within the chamber of e-cigarette is heated to roughly 100-250 °C to create an aerosolized vapor. This is thought to result in pyrolysis of the e-liquid and could also lead to decomposition of other liquid ingredients. The aerosol (mist) produced by an e-cigarette is commonly but inaccurately called vapor. In physics, a vapor is a substance in the gas phase whereas an aerosol is a suspension of tiny particles of liquid, solid or both within a gas.The power output of the e-cigarette is correlated to the voltage and resistance (P = V2/R, in watts), which is one aspect that impacts the production and the amount of toxicants of e-cigarette vapors. The power generated by the heating coil is not based solely on the voltage because it also relies upon the current, and the resultant temperature of the e-liquid relies upon the power output of the heating element. The production of vapor also relies upon the boiling point of the solvent. Propylene glycol boils at 188 °C, while glycerin boils at 290 °C. The higher temperature reached by glycerin may impact the toxicants emitted by the e-cigarette. The boiling point for nicotine is 247 °C. Each e-cigarette company's designs generate different amounts of heating power.The evidence indicates that larger capacity tanks, increasing the coil temperature, and dripping configurations seem to be end user modified designs adopted by e-cigarette companies. Variable voltage e-cigarettes can raise the temperature within the device to allow users to adjust the e-cigarette vapor. No firm information is available on the temperature differences in variable voltage devices. The length of time that the e-cigarette vapor is being heated within the device also affects the e-cigarette vapor properties. When the temperature of the heating element rises, the temperature of the e-cigarette vapor in the air rises. The hotter air can support more e-liquid air density.E-cigarettes have a wide array of engineering designs. The differences in e-cigarette manufacturing materials are broad and often unknown. Concern exists over lack of quality control. E-cigarette companies often lack manufacturing standards or are non-existent. Some e-cigarettes are designed and manufactured to a high standard. The manufactured standards of e-cigarettes are not equivalent to pharmaceutical products. Improved manufacturing standards could reduce the levels of metals and other chemicals found in e-cigarette vapor. Quality control is influenced by market forces.The engineering designs typically affect the nature, number, and size of particles generated. High amounts of vapor particle deposition are believed to enter into the lungs with each puff because the particle size in e-cigarette vapors is within the respiratory range. After a puff, the inhaled vapor changes in the size distributions of particles in the lungs. This results in smaller exhaled particles. E-cigarette vapor is made up of fine and ultrafine particles of particulate matter. Vaping generates particulate matter 2.5 μm or less in diameter (PM2.5), but at notably less concentrations compared to cigarette smoke. Particle concentrations from vaping ranged from 6.6 to 85.0 μg/m3.Particle-size distributions of particulate matter from vaping differ across studies. The longer the puff duration the greater the amount of particles produced. The greater the amount of nicotine in the e-liquid the greater the amount of particles produced. Flavoring does not influence the particle emissions. The various kinds of devices such as cig-a-likes, medium-sized vaporizers, tanks, or mods may function at different voltages and temperatures. Thus, the particle size of the e-cigarette vapor can vary, due to the device used. Comparable to cigarette smoke, the particle size distribution mode of e-cigarette vapor ranged from 120 to 165 nm, with some vaping devices producing more particles than cigarette smoke.
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Composition of electronic cigarette aerosol
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Particulate matter
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Ingredients Exactly what the e-cigarette vapor consists of varies in composition and concentration across and within manufacturers. Limited data exists regarding their chemistry. The e-cigarette vapor usually contains propylene glycol, glycerin, nicotine, flavors, aroma transporters, and other substances. The levels of solvents and flavors are not provided on the labels of e-liquids, according to many studies.The yield of chemicals found in the e-cigarette vapor varies depending on, several factors, including the e-liquid contents, puffing rate, and the battery voltage. A 2017 review found that "Adjusting battery wattage or the inhaled airflow modifies the amount of vapor and chemical density in each puff." A high amount of e-liquid contains propylene glycol and/or glycerin.Limited but consistent data indicates that flavoring agents are at levels above the National Institute for Occupational Safety and Health safety limit. High amounts of flavoring agents have been found in e-cigarette vapors.The main chemical found in the e-cigarette vapor was propylene glycol. A 2013 study, under close to real-life conditions in an emission test chamber, using a test subject who took six forceful puffs from an e-cigarette, resulted in a high level of propylene glycol released into the air. The next greatest amount in the e-cigarette vapor was nicotine.Cig-a-likes are usually first-generation e-cigarettes, tanks are commonly second-generation e-cigarettes, tanks that let vapers adjust the voltage setting are third-generation e-cigarettes, and tanks that have the ability for sub ohm (Ω) vaping and to set temperature control limits are fourth-generation devices. Vaping nicotine using e-cigarettes differs from smoking traditional cigarettes in many ways. First-generation e-cigarettes are often designed to simulate smoking traditional cigarettes; they are low-tech vaporizers with a limited number of settings. First-generation devices usually deliver a smaller amount nicotine. Second-generation and third-generation e-cigarettes use more advanced technology; they have atomizers (i.e., heating coils that convert e-liquids into vapor) which improve nicotine dispersal and house high capacity batteries.Third-generation and fourth-generation devices represent a diverse set of products and, aesthetically, constitute the greatest departure from the traditional cigarette shape, as many are square or rectangular and feature customizable and rebuildable atomizers and batteries. Cartomizers are similar in design to atomizers; their main difference is a synthetic filler material wrapped around the heating coil. Clearomizers are now commonly available and similar to cartomizers, but they include a clear tank of a larger volume and no filler material; additionally they have a disposable head containing the coil(s) and wicks. Vaping enthusiasts often begin with a cig-a-like first-generation device and tend to move towards using a later-generation device with a larger battery.Cig-a-likes and tanks are among the most popular devices. But tanks vaporize nicotine more effectively, and there are a greater selection of flavors and levels of nicotine, and are usually used by experienced users. Under five minutes of cig-a-like vaping, blood nicotine levels can elevate to about 5 ng/ml, while under 30 minutes of using 2 mg of nicotine gum, blood nicotine levels ranged from 3–5 ng/ml. Under five minutes of using tank systems by experienced vapers, the elevation in blood nicotine level can be 3–4 times greater.Many devices lets the user use interchangeable components, which result in variations in the e-cigarette vaporized nicotine. One of the primary features of the more recent generation of devices is that they contain larger batteries and are capable of heating the liquid to a higher temperature, potentially releasing more nicotine, forming additional toxicants, and creating larger clouds of particulate matter. A 2017 review found "Many e-cig users prefer to vape at high temperatures as more aerosol is generated per puff. However, applying a high voltage to a low-resistance heating coil can easily heat e-liquids to temperatures in excess of 300 °C; temperatures sufficient to pyrolyze e-liquid components." The nicotine levels in the e-cigarette vapor greatly varies across companies. The nicotine levels in the e-cigarette vapor also varies greatly either from puff-to-puff or among devices of the same company. Nicotine intake across users using same device or liquid varies substantially. Puffing characteristics differ between smoking and vaping. Vaping typically require more 'suck' than cigarette smoking. Factors that influence the level of blood nicotine concentrations include nicotine content in a device; how well the nicotine is vapored from the liquid reservoir; and additives that may contribute to nicotine intake. Nicotine intake from vaping also relies upon the habits of the user.Other factors that influence nicotine intake include engineering designs, battery power, and vapor pH. For instance, some e-cigarettes have e-liquids that contain amounts of nicotine comparable to other companies, though the e-cigarette vapor contains far less amounts of nicotine. Puffing behavior substantially varies. New e-cigarette users tend to take shorter puffs than experienced users which may result in less nicotine intake. Among experienced users there is a wide range in puffing time. Some experienced users may not adapt to increase their puffing time. Inexperienced users vape less forcefully than experienced users.E-cigarettes share a common design, but construction variations and user alterations generate varied nicotine delivery. Lowering the heater resistance probably increases the nicotine concentration. Some 3.3 V vaping devices using low-resistance heating elements such as an ohm of 1.5, containing 36 mg/mL liquid nicotine can obtain blood nicotine levels after 10 puffs that may be higher than with traditional cigarettes. A 2015 study evaluated "a variety of factors that can influence nicotine yield and found that increasing power output from 3 to 7.5 W (an approximately 2.5-fold increase), by increasing the voltage from 3.3 to 5.2 V, led to an approximately 4- to 5-fold increase in nicotine yield." A 2015 study, using a model to approximate indoor air workplace exposure, anticipates greatly reduced exposure to nicotine from e-cigarettes than traditional cigarettes.A 2016 World Health Organization (WHO) report found "nicotine in SHA [second-hand aerosol] has been found between 10 and 115 times higher than in background air levels." A 2015 Public Health England (PHE) report concluded that e-cigarettes "release negligible levels of nicotine into ambient air". A 2016 Surgeon General of the United States report stated that the exposure to nicotine from e-cigarette vaping is not negligible and is higher than in non-smoking environments. Vaping generates more surrounding air levels of particulate matter and nicotine in indoor areas than background air levels. Extended indoor e-cigarette use in rooms that are not sufficiently ventilated could surpass occupational exposure limits to the inhaled metals.The e-cigarette vapor may also contain tiny amounts of toxicants, carcinogens, and heavy metals. The majority of toxic chemicals found in e-cigarette vapor are below 1% of the corresponding levels permissible by workplace exposure standards, but the threshold limit values for workplace exposure standards are generally much higher than levels considered satisfactory for outdoor air quality. Some chemicals from exposures to the e-cigarette vapor could be higher than workplace exposure standards. A 2018 PHE report stated that the toxicants found in e-cigarette vapor are less than 5% and the majority are less than 1% in comparison with traditional cigarettes.Although several studies have found lower levels of carcinogens in e-cigarette aerosol compared to smoke emitted by traditional cigarettes, the mainstream and second-hand e-cigarette aerosol has been found to contain at least ten chemicals that are on California's Proposition 65 list of chemicals known to cause cancer, birth defects, or other reproductive harm, including acetaldehyde, benzene, cadmium, formaldehyde, isoprene, lead, nickel, nicotine, N-Nitrosonornicotine, and toluene. Free radicals produced from frequent e-cigarette use is estimated to be greater than compared to air pollution. E-cigarette vapor can contain a range of toxicants, and since they have been be used in methods unintended by the producer such as dripping or mixing liquids, this could result in generating greater levels of toxicants."Dripping", where the liquid is dripped directly onto the atomizer, could yield a higher level of nicotine when the liquid contains nicotine, and also a higher level of chemicals may be generated from heating the other contents of the liquid, including formaldehyde. Dripping may result in higher levels of aldehydes. Considerable pyrolysis might occur during dripping. Emissions of certain compounds increased over time during use as a result of increased residues of polymerization by-products around the coil. As the devices age and get dirty, the constituents they produce may become different. Proper cleaning or more routine replacement of coils may lower emissions by preventing buildup of residual polymers.
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Composition of electronic cigarette aerosol
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Particulate matter
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E-liquid carrying agents Glycerin and/or propylene glycol is used in liquid vapes. Vapes for cloud-chasing usually don't contain other ingredients.
Glycerin Glycerin (often called vegetable glycerin, or VG) was long thought to be a safe option. However, the carcinogen formaldehyde is known as an impurity found in propylene glycol and glycerol vapor degradation.
Propylene glycol Propylene glycol (often referred to as PG).
Misc MCT oil Flavoring Flavoring are often added to e-liquids as well as dry smoke blends. There are currently over 7,700 e-liquid flavors available, most have not been laboratory tested for toxicity.There are numerous flavors (e.g., fruit, vanilla, caramel, coffee) of e-liquid available. There are also flavorings that resemble the taste of cigarettes.
Psychoactive substances Cannabinoids CBD is common in vape products. Vaped or smoked CBD heated to 250-300 C will partially be converted to THC. CBD is one among the most suspected ingredients involved in VAPI.Synthetic cannabinoids are increasingly offered in e-cigarette form as "c-liquid".
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Composition of electronic cigarette aerosol
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Particulate matter
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Nicotine E-liquids were purchased from retailers and via online for a 2013 study. The Royal College of General Practitioners stated in 2016 that "To date 42 chemicals have been detected in ENDS aerosol – though with the ENDS market being unregulated there is significant variation between devices and brands."E-liquid nicotine concentrations vary. The amount of nicotine stated on the labels of e-liquids can be very different from analyzed samples. Some e-liquids sold as nicotine-free contained nicotine, and some of them were at substantial levels. The analyzed liquids nicotine levels were between 14.8 and 87.2 mg/mL and the actual amount varied from the stated amount by as much as 50%.Possibly, 60–70% of the nicotine is vaporized. E-cigarettes without nicotine is also available. Via nicotine-containing e-cigarettes, nicotine is absorbed through the upper and lower respiratory tract. A greater amount of nicotine is possibly absorbed through oral mucosa and upper airways. The composition of the e-liquid may affect nicotine delivery. E-liquid containing glycerin and propylene glycol delivers nicotine more efficiently than a glycerin-based liquid with the same amount of nicotine. It is believed that propylene glycol vaporizes quicker than glycerin, which subsequently transports a higher amount of nicotine to the user.Vaping appears to give less nicotine per puff than cigarette smoking. Early devices typically delivered low amounts of nicotine than that of traditional cigarettes, but newer devices containing a high amount of nicotine in the liquid may deliver nicotine at amounts similar to that of traditional cigarettes. Similar to traditional cigarettes, e-cigarettes rapidly delivers nicotine to the brain. The peak concentration of nicotine delivered by e-cigarettes is comparable to that of traditional cigarettes. E-cigarettes take longer to reach peak concentration than with traditional cigarettes, but they provide nicotine to the blood quicker than nicotine inhalers. The yield of nicotine users obtain is similar to that of nicotine inhalers.Newer e-cigarette models deliver nicotine to the blood quicker than with older devices. E-cigarettes with more powerful batteries can delivery a higher level of nicotine in the e-cigarette vapor. Some research indicates that experienced e-cigarette users can obtain nicotine levels similar to that of smoking. Some vapers can obtain nicotine levels comparable to smoking, and this ability generally improves with experience. E‐cigarettes users still may be able to obtain similar blood nicotine levels compared with traditional cigarettes, particularly with experienced smokers, but it takes more time to obtain such levels.
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Composition of electronic cigarette aerosol
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Particulate matter
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By-products Metals and other content A 2020 systematic review found aluminum, antimony, arsenic, cadmium, cobalt, chromium, copper, iron, lead, manganese, nickel, selenium, tin, and zinc, possibly due to coil contact.Metal parts of e-cigarettes in contact with the e-liquid can contaminate it. The temperature of the atomizer can reach up to 500 °F. The atomizer contains metals and other parts where the liquid is kept, and an atomizer head is made of a wick and metal coil which heats the liquid. Due to this design, some metals are potentially found in the e-cigarette vapor. E-cigarette devices differ in the amount of metals in the e-cigarette vapor. This may be associated with the age of various cartridges, and also what is contained in the atomizers and coils.Usage behavior may contribute to variations in the specific metals and amounts of metals found in e-cigarette vapor. An atomizer made of plastics could react with e-liquid and leach plasticizers. The amounts and kinds of metals or other materials found in the e-cigarette vapor is based on the material and other manufacturing designs of the heating element. E-cigarettes devices can be made with ceramics, plastics, rubber, filament fibers, and foams, of which some can be found in the e-cigarette vapor.E-cigarette parts, including exposed wires, wire coatings, solder joints, electrical connectors, heating element material, and vitreous fiber wick material, account for the second significant source of substances, to which users may be exposed. Metal and silicate particles, some of which are at higher levels than in traditional cigarettes, have been detected in e-cigarette aerosol, resulting from degradation from the metal coil used to heat the solution. Other materials used are Pyrex glass rather than plastics and stainless steel rather than metal alloys.Metals and metal nanoparticles have been found in tiny amounts in e-cigarette vapor. Aluminum, antimony, barium, boron, cadmium, chromium, copper, iron, lanthanum, lead, magnesium, manganese, mercury, nickel, potassium, silicate, silver, sodium, strontium, tin, titanium, zinc, and zirconium have been found in e-cigarette vapor. Arsenic may leach from the device itself and may end up in the liquid, and then the e-cigarette vapor. Arsenic has been found in some e-liquids, and in e-cigarette vapor.Considerable differences in exposure to metals have been identified from the e-cigarettes tested, particularly metals such as cadmium, lead, and nickel. Poor quality first-generation e-cigarettes produce several metals in their vapor, in some cases the amounts were greater than with cigarette smoke. A 2013 study found metal particles in the e-cigarette vapor were at concentrations 10-50 times less than permitted in inhalation medicines.A 2018 study found significantly higher amounts of metals in e-cigarette vapor samples in comparison with the e-liquids before they came in contact with the customized e-cigarettes that were provided by everyday e-cigarette users. Lead and zinc were 2,000% higher and chromium, nickel, and tin were 600% higher. The e-cigarette vapor levels for nickel, chromium, lead, manganese surpassed occupational or environmental standards for at least 50% of the samples. The same study found 10% of the e-liquids tested contained arsenic and the amounts remained about the same as the e-cigarette vapor.The average amounts of exposure to cadmium from 1,200 e-cigarette puffs were found to be 2.6 times lower than the chronic Permissible Daily Exposure from inhalation medications, outlined by the US Pharmacopeia. One sample tested resulted in daily exposure 10% greater than chronic PDE from inhalation medications, while in four samples the amounts were comparable to outdoor air levels. Cadmium and lead have been found in the e-cigarette vapor at 2–3 times greater levels than with a nicotine inhaler. A 2015 study stated the amount of copper have been found to be six times greater than with cigarette smoke. A 2013 study stated the levels of nickel have been found to be 100 times higher than cigarette smoke.A 2014 study stated the levels of silver have been found to be at a greater amount than with cigarette smoke. Increased amounts of copper and zinc in vapor generated by some e-cigarettes may be the result of corrosion on the brass electrical connector as indicated in particulates of copper and zinc in e-liquid. In addition, a tin solder joint may be subjected to corrosion, which may result in increased amounts of tin in some e-liquids.Generally low levels of contaminates may include metals from the heating coils, solders, and wick. The metals nickel, chromium, and copper coated with silver have been used to make the normally thin-wired e-cigarette heating elements. The atomizers and heating coils possibly contain aluminum. They likely account for most of the aluminum in the e-cigarette vapor. The chromium used to make the atomizers and heating coils is probably the origin of the chromium. Copper is commonly used to make atomizers. Atomizers and heating coils commonly contain iron.Cadmium, lead, nickel, and silver originated from the heating element. Silicate particles may originate from the fiberglass wicks. Silicate nanoparticles have been found in vapors generated from the fiberglass wicks. Tin may originate from the e-cigarette solder joints. Nickel potentially found in the e-cigarette vapor may originate from the atomizer and heating coils. The nanoparticles can be produced by the heating element or by pyrolysis of chemicals directly touching the wire surface.Chromium, iron, tin, and nickel nanoparticles potentially found in the e-cigarette vapor can originate from the e-cigarette heating coils. Kanthal and nichrome are frequently used heating coils which may account for chromium and nickel in the e-cigarette vapor. Metals can originate from the "cartomizer" from the later-generation devices where an atomizer and cartridge are constructed into one unit. Metal and glass particles can be created and vaporized because of the heating of the liquid with glass fiber.
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Composition of electronic cigarette aerosol
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Particulate matter
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Solutions Metal coils coated with microporous ceramic have been developed to protect against oxidation of metals.
Comparison of levels of metals in e-cigarette aerosol Abbreviations: EC, electronic cigarette; NM, not measured.
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Composition of electronic cigarette aerosol
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Particulate matter
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∗The findings are a comparison between e-cigarette daily usage and the regulatory limits of chronic Permissible Daily Exposure from inhalation medications outlined by the US Pharmacopeia for cadmium, chromium, copper, lead and nickel, the Minimal Risk Level outlined by the Agency for Toxic Substances and Disease Registry for manganese and the Recommended Exposure Limit outlined by the National Institute for Occupational Safety and Health for aluminum, barium, iron, tin, titanium, zinc and zirconium, referring to a daily inhalation volume of 20 m3 air and a 10-h volume of 8.3 m3; values are in μg.
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Composition of electronic cigarette aerosol
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Particulate matter
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Carbonyls and other content E-cigarette makers do not fully disclose information on the chemicals that can be released or synthesized during use. The chemicals in the e-cigarette vapor can be different than with the liquid. Once vaporized, the ingredients in the e-liquid go through chemical reactions that form new compounds not previously found in the liquid. Many chemicals including carbonyl compounds such as formaldehyde, acetaldehyde, acrolein, and glyoxal can inadvertently be produced when the nichrome wire (heating element) that touches the e-liquid is heated and chemically reacted with the liquid. Acrolein and other carbonyls have been found by in e-cigarette vapors that were created by unmodified e-cigarettes, indicating that formation of these compounds could be more common than previously thought.A 2017 review found "Increasing the battery voltage from 3.3 V to 4.8 V doubles the amount of e-liquid vapourized and increases the total aldehyde generation more than threefold, with acrolein emission increasing tenfold." A 2014 study stated that "increasing the voltage from 3.2–4.8 V resulted in a 4 to >200 times increase in the formaldehyde, acetaldehyde, and acetone levels". The amount of carbonyl compounds in e-cigarette aerosols varies substantially, not only among different brands but also among different samples of the same products, from 100-fold less than tobacco to nearly equivalent values.The propylene glycol-containing liquids produced the most amounts of carbonyls in e-cigarette aerosols. Propylene glycol could turn into propylene oxide when heated and aerosolized. Glycerin may generate acrolein when heated at hotter temperatures. Some e-cigarette products had acrolein identified in the e-cigarette vapor, at greatly lower amounts than in cigarette smoke. Several e-cigarette companies have replaced glycerin and propylene glycol with ethylene glycol. In 2014, most e-cigarettes companies began to use water and glycerin as replacement for propylene glycol.In 2015, manufacturers attempted to reduce the formation of formaldehyde and metal substances of the e-cigarette vapor by producing an e-liquid in which propylene glycol is replaced by glycerin. Acetol, beta-nicotyrine, butanal, crotonaldehyde, glyceraldehyde, glycidol, glyoxal, dihydroxyacetone, dioxolanes, lactic acid, methylglyoxal, myosmine, oxalic acid, propanal, pyruvic acid, and vinyl alcohol isomers have been found in the e-cigarette vapor. Hydroxymethylfurfural and furfural have been found in the e-cigarette vapors. The amounts of furans in the e-cigarette vapors were highly associated with power of the e-cigarette and amount of sweetener.The amount of carbonyls vary greatly among different companies and within various samples of the same e-cigarettes. Oxidants and reactive oxygen species (OX/ROS) have been found in the e-cigarette vapor. OX/ROS could react with other chemicals in the e-cigarette vapor because they are highly reactive, causing alterations its chemical composition. E-cigarette vapor have been found to contain OX/ROS at about 100 times less than with cigarette smoke. A 2018 review found e-cigarette vapor containing reactive oxygen radicals seem to be similar to levels in traditional cigarettes. Glyoxal and methylglyoxal found in e-cigarette vapors are not found in cigarette smoke.
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Composition of electronic cigarette aerosol
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Particulate matter
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Contamination with various chemicals have been identified. Some products contained trace amounts of the drugs tadalafil and rimonabant. The amount of either of these substances that is able to transfer from liquid to vapor phase is low.The nicotine impurities in the e-liquid varies greatly across companies. The levels of toxic chemicals in e-cigarette vapor is in some cases similar to that of nicotine replacement products. Tobacco-specific nitrosamines (TSNAs) such as nicotine-derived nitrosamine ketone (NNK) and N-Nitrosonornicotine (NNN) and tobacco-specific impurities have been found in the e-cigarette vapor at very low levels, comparable to amounts found in nicotine replacement products. A 2014 study that tested 12 e-cigarette devices found that most of them contained tobacco-specific nitrosamines in the e-cigarette vapor. In contrast, the one nicotine inhaler tested did not contain tobacco-specific nitrosamines.N-Nitrosoanabasine and N'-Nitrosoanatabine have been found in the e-cigarette vapor at lower levels than cigarette smoke. Tobacco-specific nitrosamines (TSNAs), nicotine-derived nitrosamine ketone (NNK), N-Nitrosonornicotine (NNN), and N′-nitrosoanatabine have been found in the e-cigarette vapor at different levels between different devices. Since e-liquid production is not rigorously regulated, some e-liquids can have amounts of impurities higher compared to limits for pharmaceutical-grade nicotine products.m-Xylene, p-Xylene, o-Xylene, ethyl acetate, ethanol, methanol, pyridine, acetylpyrazine, 2,3,5-trimethylpyrazine, octamethylcyclotetrasiloxane, catechol, m-Cresol, and o-Cresol have been found in the e-cigarette vapor. A 2017 study found that "The maximum detected concentrations of benzene, methanol, and ethanol in the samples were higher than their authorized maximum limits as residual solvents in pharmaceutical products." Trace amounts of toluene and xylene have been found in the e-cigarette vapor.Polycyclic aromatic hydrocarbons (PAHs), aldehydes, volatile organic compounds (VOCs), phenolic compounds, flavors, tobacco alkaloids, o-Methyl benzaldehyde, 1-Methyl phenanthrene, anthracene, phenanthrene, pyrene, and cresol have been found in the e-cigarette vapor. While the cause of these differing concentrations of minor tobacco alkaloids is unknown, Lisko and colleagues (2015) speculated potential reasons may derive from the e-liquid extraction process (i.e., purification and manufacturing) used to obtain nicotine from tobacco, as well as poor quality control of e-liquid products. In some studies, small quantities of VOCs including styrene have been found in the e-cigarette vapor. A 2014 study found the amounts of PAHs were above specified safe exposure limits.Low levels of isoprene, acetic acid, 2-butanodione, acetone, propanol, and diacetin, and traces of apple oil (3-methylbutyl-3-methylbutanoate) have been found in the e-cigarette vapor. Flavoring substances from roasted coffee beans have been found in the e-cigarette vapor. The aroma chemicals acetamide and cumarine have been found in the e-cigarette vapor. Acrylonitrile and ethylbenzene have been found in the e-cigarette vapor. Benzene and 1,3-Butadiene have been found in the e-cigarette vapor at many-fold lower than in cigarette smoke.Some e-cigarettes contain diacetyl and acetaldehyde in the e-cigarette vapor. Diacetyl and acetylpropionyl have been found at greater levels in the e-cigarette vapor than is accepted by the National Institute for Occupational Safety and Health, although diacetyl and acetylpropionyl are normally found at lower levels in e-cigarettes than with traditional cigarettes. A 2018 PHE report stated that diacetyl was identified at hundreds of times in lesser amounts than found in cigarette smoke. A 2016 WHO report found that acetaldehyde from second-hand vapor was between two and eight times greater compared to background air levels.
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Composition of electronic cigarette aerosol
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Particulate matter
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Formaldehyde A 2016 WHO report found that formaldehyde from second-hand vapor was around 20% greater compared to background air levels. Normal usage of e-cigarettes generates very low levels of formaldehyde. Different power settings reached significant differences in the amount of formaldehyde in the e-cigarette vapor across different devices. Later-generation e-cigarette devices can create greater amounts of carcinogens. Some later-generation e-cigarettes let users increase the volume of vapor by adjusting the battery output voltage.Depending on the heating temperature, the carcinogens in the e-cigarette vapor may surpass the levels of cigarette smoke. E-cigarettes devices using higher voltage batteries can produce carcinogens including formaldehyde at levels comparable to cigarette smoke. The later-generation and "tank-style" devices with higher voltages (5.0 V) could produce formaldehyde at comparable or greater levels than in cigarette smoke.A 2015 study hypothesized from the data that at high voltage (5.0 V), a user, "vaping at a rate of 3 mL/day, would inhale 14.4 ± 3.3 mg of formaldehyde per day in formaldehyde-releasing agents." The 2015 study used a puffing machine showed that a third-generation e-cigarette turned on to the maximum setting would create levels of formaldehyde between five and 15 times greater than with cigarette smoke. A 2015 PHE report found that high levels of formaldehyde only occurred in overheated "dry-puffing", and that "dry puffs are aversive and are avoided rather than inhaled", and "At normal settings, there was no or negligible formaldehyde release."A 2018 study confirmed e-cigarettes can emit formaldehyde at high levels more than 5 times higher than what is reported for cigarette smoke) at moderate temperatures and under conditions that have been reported to be non-averse to users. But e-cigarette users may "learn" to overcome the unpleasant taste due to elevated aldehyde formation, when the nicotine craving is high enough. High voltage e-cigarettes are capable of producing large amounts of carbonyls. Reduced voltage (3.0 V) e-cigarettes had e-cigarette aerosol levels of formaldehyde and acetaldehyde roughly 13 and 807-fold less than with cigarette smoke.
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Composition of electronic cigarette aerosol
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Chemical analysis of e-cigarette cartridges, solutions, and aerosol
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Abbreviations: TSNA, tobacco specific nitrosoamines; LC-MS, liquid chromatography-mass spectrometry; MAO-A and B, monoamineoxidase A and B; PAH, polycyclic aromatic hydrocarbons; GS-MS, gas chromatography – mass spectrometry; ICP-MS, inductively coupled plasma – mass spectrometry; CO, carbon monoxide, VOC, volatile organic compounds; UPLC-MS, ultra-performance liquid chromatography-mass spectrometry; HPLC-DAD-MMI-MS, high performance liquid chromatography-diode array detector-multi-mode ionization-mass spectrometry.
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